Polarization-independent grating coupler for micrometric silicon rib waveguides - Alonso-Ramos, C.; Zavargo-Peche, L.; Ortega-Moñux, A.; Halir, R.; Molina-Fernández, I.; Cheben, P. (Optics Letters, 2012)
Grating couplers are a promising approach to implement efficient fiber-chip coupling. However, their strong polarization dependence makes dual-polarization operation challenging. In this Letter we propose, for the first time, a polarization-independent grating coupler for thick rib silicon-on-insulator (SOI) waveguides. Coupling efficiency is optimized by designing the grating pitch and duty cycle, without varying the bottom oxide thickness, which significantly simplifies practical implementation. Directivity of the grating coupler is enhanced by a high reflectivity layer under the bottom oxide after the selective removal of the Si substrate. Dual-polarization coupling efficiency of -2.8 dB is shown.
Keywords: Coupling efficiency; Directivity; Dual-polarizations; Duty cycles; Fiber chip coupling; Grating couplers; Grating pitch; High reflectivity; Oxide thickness; Polarization dependence; Polarization-independent; Practical implementation; Selective removal; Si substrates; Silicon on insulator waveguide; Silicon rib waveguides; Waveguides; Polarization

Measurement of the transverse electric field profile of light by a self-referencing method with direct phase determination - Bamber, C.; Sutherland, B.; Patel, A.; Stewart, C.; Lundeen, J. S. (Optics Express, 2012)
We present a method for measuring the transverse electric field profile of a beam of light which allows for direct phase retrieval. The measured values correspond, within a normalization constant, to the real and imaginary parts of the electric field in a plane normal to the direction of propagation. This technique represents a self-referencing method for probing the wavefront characteristics of light.

Slowing light down by low magnetic fields: pulse delay by transient spectral hole-burning in ruby - Riesen, Hans; Rebane, Aleksander K.; Szabo, Alex; Carceller, Ivana (Optics Express, 2012)
We report on the observation of slow light induced by transient spectral hole-burning in a solidthat is based on excited-state population storage. Experiments were conducted in the R1-line (2E-4A2 transition) of a 2.3 mm thick pink ruby (Al2O3:Cr(III) 130 ppm). Importantlythe pulse delay can be controlled by the application of a low external magnetic field B||c≪9 mT and delays of up to 11 ns with minimal pulse distortion are observed for ∼55 ns Gaussian pulses. The delay corresponds to a group velocity value of ∼c/1400. The experiment is very well modelled by linear spectral filter theory and the results indicate the possibility of using transient hole-burning based slow light experiments as a spectroscopic technique.
Keywords: External magnetic field; Gaussian pulse; Group velocities; Hole burning; Linear spectral; Low magnetic fields; Pulse delay; Pulse distortion; Spectral-hole burning; Spectroscopic technique; Chromium compounds; Magnetic fields; Ruby; Slow light; Computer simulation; Radiation scattering; Refractometry

Hadamard multiplexing in laser ultrasonics - Rousseau, Guy; Blouin, Alain (Optics Express, 2012)
In state-of-the-art laser ultrasonics (LU), the signal-to-noise ratio (SNR) is limited by the shot noise of the detected laser radiation. Further improving the SNR then requires averaging multiple signals or increasing generation and/or detection laser intensities. The former strategy is time consuming and the latter leads to surface damages. For signal-independent limiting noises, Hadamard multiplexing increases the SNR by averaging multiple signals in parallel using a single detector. Here we consider the use of Hadamard multiplexing in LU for the non-contact ultrasonic inspection of materials. By using 31 element Hadamard masks to modulate the spatial intensity distribution of the generation laser beam, the measured SNR is improved by a factor 2.8, in good agreement with the expected multiplexing or Fellgett advantage. In contrast to many other applications of Hadamard multiplexing, the SNR is improved for shot-noise-limited measurements since the shot noise level is independent of the signal in LU. The Hadamard multiplexing of the detection laser beam is also considered but can only lead to a throughput or Jacquinot advantage. However, for pulse-echo LU, the Hadamard multiplexing of both generation and detection laser beams allows using the synthetic aperture focusing technique (SAFT).
Keywords: Hadamard multiplexing; Laser intensities; Laser ultrasonics; Non-contact ultrasonic inspection; Pulse echoes; Shot-noise level; Signaltonoise ratio (SNR); Spatial intensity distribution; Surface damages; Synthetic aperture focusing techniques; Chemical detection; Detectors; Laser beams; Shot noise; Signal detection; Signal to noise ratio

Simultaneous retrieval of fluidic refractive index and surface adsorbed molecular film thickness using silicon wire waveguide biosensors - Atsumi, Yuki; Xu, Dan-Xia; Delâge, André; Schmid, Jens H.; Vachon, Martin; Cheben, Pavel; Janz, Siegfried; Nishiyama, Nobuhiko; Arai, Shigehisa (Optics Express, 2012)
For silicon wire based ring resonator biosensors, we investigate the simultaneous retrieval of changes in the fluidic refractive index Δn c and surface adsorbed molecular film thickness ΔdF. This can be achieved by monitoring the resonance shifts of the sensors operating in the TE and TM polarizations at the same time. Although this procedure is straightforward in principle, significant retrieval errors can be introduced due to deviations in the sensor waveguide cross-sections from their nominal values in the range commonly encountered for silicon photonic wire devices. We propose a method of determining the fabricated waveguide size using the group indices derived from measured free spectral range (FSR) of the resonators. We further demonstrate that using experimentally measured group index values, the waveguide size can be determined to accuracies of ± 2 nm in width and ± 1 nm in height. By using this procedure, Δn c and ΔdF can be obtained to a precision of within 10% of the true values using optically measurable parameters, improving the retrieval accuracy by more than 3 times.

NeuroTouch: a physics-based virtual simulator for cranial microneurosurgery training - Delorme, Sébastien; Laroche, Denis; DiRaddo, Robert; F. Del Maestro, Rolando (Neurosurgery, 2012)
BACKGROUND: A virtual reality neurosurgery simulator with haptic feedback may help in the training and assessment of technical skills requiring the use of tactile and visual cues. OBJECTIVE: To develop a simulator for craniotomy-based procedures with haptic and graphics feedback for implementation by universities and hospitals in the neurosurgery training curriculum. METHODS: NeuroTouch was developed by a team of more than 50 experts from the National Research Council Canada in collaboration with surgeons from more than 20 teaching hospitals across Canada. Its main components are a stereovision system, bimanual haptic tool manipulators, and a high-end computer. The simulation software engine runs 3 processes for computing graphics, haptics, and mechanics. Training tasks were built from magnetic resonance imaging scans of patients with brain tumors. RESULTS: Two training tasks were implemented for practicing skills with 3 different surgical tools. In the tumor-debulking task, the objective is complete tumor removal without removing normal tissue, using the regular surgical aspirator (suction) and the ultrasonic aspirator. The objective of the tumor cauterization task is to remove a vascularized tumor with an aspirator while controlling blood loss using bipolar electrocautery. CONCLUSION: NeuroTouch prototypes have been set up in 7 teaching hospitals across Canada, to be used for beta testing and validation and evaluated for integration in a neurosurgery training curriculum.
Keywords: Computer simulation, Craniotomy, Neurosurgery, Teaching, Training

Tailored SWCNT functionalization optimized for compatibility with epoxy matrices - Martinez-Rubi, Y.; Gonzalez-Dominguez, J. M.; Ansón-Casaos, A.; Kingston, C. T.; Daroszewska, M.; Barnes, M.; Hubert, P.; Cattin, C.; Martinez, M. T.; Simard, B. (Nanotechnology, 2012)
We have modified single walled carbon nanotubes (SWCNTs) with well defined matrix-based architectures to improve interface interaction in SWCNT/epoxy composites. The hardener and two pre-synthesized oligomers containing epoxy and hardener moieties were covalently attached to the SWCNT walls by insitu diazonium or carboxylic coupling reactions. In this way, SWCNTs bearing amine or epoxide-terminated fragments of different molecular weights, which resemble the chemical structure of the cured resin, were synthesized. A combination of characterization techniques such as Raman and infrared absorption (FTIR) spectroscopy, elemental analysis and coupled thermogravimetry-FTIR spectroscopy were used to identify both the functional groups and degree of functionalization of SWCNTs synthesized by the laser ablation and arc-discharge methods. Depending on the type of reaction employed for the chemical functionalization and the molecular weight of the attached fragment, it was possible to control the degree of functionalization and the electronic properties of the functionalized SWCNTs. Improved dispersion of SWCNTs in the epoxy matrix was achieved by direct integration without using solvents, as observed from optical microscopy and rheology measurements of the SWCNT/epoxy mixtures. Composite materials using these fillers are expected to exhibit improved properties while preserving the thermosetting architecture. © 2012 IOP Publishing Ltd.
Keywords: Arc-discharge method; Characterization techniques; Chemical functionalization; Coupling reaction; Direct integration; Epoxy matrices; FTIR; Interface interaction; Rheology measurement; Chemical bonds; Electronic properties; Functional groups; Molecular weight; Oligomers; Optical microscopy; Thermogravimetric analysis; Thermosets; Fourier transform infrared spectroscopy

Interplay between crystal phase purity and radial growth in InP nanowires - Poole, P. J.; Dalacu, D.; Wu, X.; Lapointe, J.; Mnaymneh, K. (Nanotechnology, 2012)
The interplay between crystal phase purity and radial growth in InP nanowires is investigated. By modifying the growth rate and V/III ratio, regions of high or low stacking fault density can be controllably introduced into wurtzite nanowires. It is found that regions with high stacking fault density encourage radial growth. Through careful choice of growth conditions pure wurtzite InP nanowires are then grown which exhibit narrow 4.2K photoluminescence linewidths of 3.7meV at 1.490meV, and no evidence of emission related to stacking faults or zincblende insertions.
Keywords: Condensed matter: electrical, magnetic and optical; Semiconductors; Surfaces, interfaces and thin films; Condensed matter: structural, mechanical & thermal; Nanoscale science and low-D systems

HR5907: discovery of the most rapidly rotating magnetic early B-type star by the MiMeS Collaboration - Grunhut, J. H.; Rivinius, T.; Wade, G. A.; Townsend, R. H. D.; Marcolino, W. L. F.; Bohlender, D. A.; Szeifert, T.; Petit, V.; Matthews, J. M.; Rowe, J. F.; Moffat, A. F. J.; Kallinger, T.; et al. (Monthly Notices of the Royal Astronomical Society, 2012)
We report the discovery and analysis of a very strong magnetic field in the rapidly rotating early B-type star HR5907, based on observations obtained as part of the Magnetism in Massive Stars (MiMeS) project. We infer a rotation period of 0.508276 +0.000015 -0.000012d from photometric and Hα EW measurements, making this the shortest period, non-degenerate, magnetic massive star known to date. From the comparison of IUE UV and optical spectroscopy with LTE bruce/kylie models we find a solid-angle integrated, uniform black-body temperature of 17000 ± 1000K, a projected rotational velocity of 290 ± 10kms -1, an equatorial radius of 3.1 ± 0.2R ⊙, a stellar mass of 5.5 ± 0.5M ⊙, and an inclination angle of the rotation axis to our line-of-sight of 70 ± 10°. Our measurements of the longitudinal magnetic field, which vary between -500 and -2000G, phase coherently with the rotation period and imply a surface dipole field strength of ∼15.7kG. On the other hand, from fits to mean Least-Squares Deconvolved Stokes V line profiles we infer a dipole field strength of ∼10.4kG. This disagreement may result from a magnetic configuration more complex than our model, and/or from the non-uniform helium surface abundance distribution. In either case we obtain a magnetic obliquity nearly aligned with the rotation axis Our optical spectroscopy also shows weak variability in carbon, silicon and nitrogen lines. The emission variability in hydrogen Balmer and Paschen lines indicates the presence of a dense, highly structured magnetosphere, interpreted as a centrifugally supported, magnetically confined circumstellar disc. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.

Coplanar circumbinary debris discs - Kennedy, G. M.; Wyatt, M. C.; Sibthorpe, B.; Phillips, N. M.; Matthews, B. C.; Greaves, J. S. (Monthly Notices of the Royal Astronomical Society, 2012)
We present resolved Herschel images of circumbinary debris discs in the α CrB (HD 139006) and β Tri (HD13161) systems. By modelling their structure, we find that both discs are consistent with being aligned with the binary orbital planes. Though secular perturbations from the binary can bring the disc into alignment, in both cases the alignment time at the distances at which the disc is resolved is greater than the stellar age, so we conclude that the coplanarity was primordial. Neither disc can be modelled as a narrow ring, requiring extended radial distributions. To satisfy both the Herschel and mid-infrared images of the α CrB disc, we construct a model that extends from 1 to 300 au, whose radial profile is broadly consistent with a picture where planetesimal collisions are excited by secular perturbations from the binary. However, this model is also consistent with stirring by other mechanisms, such as the formation of Pluto-sized objects. The β Tri disc is modelled as a disc that extends from 50 to 400 au. A model with depleted (rather than empty) inner regions also reproduces the observations and is consistent with binary and other stirring mechanisms. As part of the modelling process, we find that the Herschel PACS (Photodetector and Array Camera & Spectrometer) beam varies by as much as 10 per cent at 70 μm and a few per cent at 100 μm. The 70 μm variation can therefore hinder image interpretation, particularly for poorly resolved objects. The number of systems in which circumbinary debris disc orientations have been compared with the binary plane is now 4. More systems are needed, but a picture in which discs around very close binaries (α CrB, β Tri and HD 98800, with periods of a few weeks to a year) are aligned, and discs around wider binaries (99 Her, with a period of 50 yr) are misaligned, may be emerging. This picture is qualitatively consistent with the expectation that the protoplanetary discs from which the debris emerged are more likely to be aligned if their binaries have shorter periods.

SiMPE: 7th Workshop on speech and sound in mobile and pervasive environments - Nanavati, Amit A.; Rajput, Nitendra; Rudnicky, Alexander; Turunen, Markku; Sandholm, Thomas; Munteanu, Cosmin; Penn, Gerald (MobileHCI'12 - Companion Proceedings of the 14th International Conference on Human Computer Interaction with Mobile Devices and Services, 2012)
The SiMPE workshop series started in 2006 [2] with the goal of enabling speech processing on mobile and embedded devices to meet the challenges of pervasive environments (such as noise) and leveraging the context they offer (such as location). SiMPE 2010 and 2011 brought together researchers from the speech and the HCI communities. Multimodality got more attention in SiMPE 2008 than it had received in the previous years. In SiMPE 2007, the focus was on developing regions. Speech User interaction in cars was a focus area in 2009. With SiMPE 2012, the 7th in the series, we hope to explore the area of speech along with sound. When using the mobile in an eyes-free manner, it is natural and convenient to hear about notifications and events. The arrival of an SMS has used a very simple sound based notification for a long time now. The technologies underlying speech processing and sound processing are quite different and these communities have been working mostly independent of each other. And yet, for multimodal interactions on the mobile, it is perhaps natural to ask whether and how speech and sound can be mixed and used more effectively and naturally.
Keywords: Audio interaction; Developing regions; Embedded device; Multi-Modal Interactions; Multi-modality; Pervasive environments; Previous year; Sound processing; User interaction; Acoustic waves; Human computer interaction; Mobile computing; Mobile devices; Speech processing; Ubiquitous computing; Audio acoustics

Reconciling Planck constant determinations via watt balance and enriched-silicon measurements at NRC Canada - Steele, A. G.; Meija, J.; Sanchez, C. A.; Yang, L.; Wood, B. M.; Sturgeon, R. E.; Mester, Z.; Inglis, A. D. (Metrologia, 2012)
The next revision to the International System of Units will emphasize the relationship between the base units (kilogram, metre, second, ampere, kelvin, candela and mole) and fundamental constants of nature (the speed of light, c, the Planck constant, h, the elementary charge, e, the Boltzmann constant, k B, the Avogadro constant, N A, etc). The redefinition cannot proceed without consistency between two complementary metrological approaches to measuring h: a 'physics' approach, using watt balances and the equivalence principle between electrical and mechanical force, and a 'chemistry' approach that can be viewed as determining the mass of a single atom of silicon. We report the first high precision physics and chemistry results that agree within 12 parts per billion: h (watt balance) = 6.626 070 63(43) × 10 -34Js and h(silicon) = 6.626 070 55(21) × 10 -34Js. When combined with values determined by other metrology laboratories, this work helps to constrain our knowledge of h to 20 parts per billion, moving us closer to a redefinition of the metric system used around the world. © 2012 BIPM & IOP Publishing Ltd.
Keywords: Avogadro constant; Boltzmann constants; Elementary charge; Equivalence principles; Fundamental constants; High precision; Mechanical force; Parts per billion; Planck constants; Single atoms; Watt balance; Engineering; Metallurgical engineering; Metric system

Investigation of low-temperature fixed points by an international star intercomparison of sealed triple-point cells - Fellmuth, B.; Wolber, L.; Head, D. I.; Hermier, Y.; Hill, K. D.; Nakano, T.; Pavese, F.; Peruzzi, A.; Rusby, R. L.; Shkraba, V.; Steele, A. G.; Steur, P. P. M.; et al. (Metrologia, 2012)
An overview of the results of an international star intercomparison of low-temperature fixed points is given. Between 1997 and 2005, 68 sealed triple-point cells (STPCs) of the twelve laboratories represented by the authors were investigated at PTB. The STPCs are used to realize the triple points of hydrogen, neon, oxygen and argon as defining fixed points of the International Temperature Scale of 1990, ITS-90. The melting curves (MCs) of all STPCs have been measured on the same experimental equipment, adhering strictly to a single measurement program. This protocol enables separation of the effects influencing the MCs and direct comparison of the thermal behaviour of the STPCs, which are quite different with respect to design, age, gas source and filling technology. In the paper, special emphasis is given to the spread of the liquidus-point temperatures and to the uncertainty of their determination. Connections between the star intercomparison and completed and ongoing international activities are also discussed. © 2012 BIPM & IOP Publishing Ltd.
Keywords: Experimental equipments; Filling technologies; Fixed points; Gas sources; Intercomparisons; International Temperature Scale of 1990; Low temperatures; Measurement programs; Melting curves; Thermal behaviours; Triple points; Argon; Hydrogen; Neon; Stars; Temperature; Source separation

The 8th international comparison of absolute gravimeters 2009: the first key comparison (CCM.G-K1) in the field of absolute gravimetry - Jiang, Z.; Pálinkáš, V.; Arias, F.E.; Liard, J.; Merlet, S.; Wilmes, H.; Vitushkin, L.; Robertsson, L.; Tisserand, L.; Pereira Dos Santos, F.; Bodart, Q.; Falk, R.; et al. (Metrologia, 2012)
The 8th International Comparison of Absolute Gravimeters (ICAG2009) took place at the headquarters of the International Bureau of Weights and Measures (BIPM) from September to October 2009. It was the first ICAG organized as a key comparison in the framework of the CIPM Mutual Recognition Arrangement of the International Committee for Weights and Measures (CIPM MRA) (CIPM 1999). ICAG2009 was composed of a Key Comparison (KC) as defined by the CIPM MRA, organized by the Consultative Committee for Mass and Related Quantities (CCM) and designated as CCM.G-K1. Participating gravimeters and their operators came from national metrology institutes (NMIs) or their designated institutes (DIs) as defined by the CIPM MRA. A Pilot Study (PS) was run in parallel in order to include gravimeters and their operators from other institutes which, while not signatories of the CIPM MRA, nevertheless play important roles in international gravimetry measurements. The aim of the CIPM MRA is to have international acceptance of the measurement capabilities of the participating institutes in various fields of metrology. The results of CCM.G-K1 thus constitute an accurate and consistent gravity reference traceable to the SI (International System of Units), which can be used as the global basis for geodetic, geophysical and metrological observations of gravity. The measurements performed afterwards by the KC participants can be referred to the international metrological reference, i.e. they are SI-traceable. The ICAG2009 was complemented by a number of associated measurements: the Relative Gravity Campaign (RGC2009), high-precision levelling and an accurate gravity survey in support of the BIPM watt balance project. The major measurements took place at the BIPM between July and October 2009. Altogether 24 institutes with 22 absolute gravimeters (one of the 22 AGs was ultimately withdrawn) and nine relative gravimeters participated in the ICAG/RGC campaign. This paper is focused on the absolute gravity campaign. We review the history of the ICAGs and present the organization, data processing and the final results of the ICAG2009. After almost thirty years of hosting eight successive ICAGs, the CIPM decided to transfer the responsibility for piloting the future ICAGs to NMIs, although maintaining a supervisory role through its Consultative Committee for Mass and Related Quantities. © 2012 BIPM & IOP Publishing Ltd.
Keywords: Absolute gravimeter; Absolute gravimetry; Absolute gravity; CIPM MRA; Gravity survey; High-precision; International Committee for Weights and Measures; International comparison; Key comparison; Mutual recognition arrangements; National metrology institutes; Pilot studies; Watt balance; Data processing; Metric system; Gravimeters

Humidity effects on calibrations of radiation therapy electrometers - Downton, B.; Walker, S. (Medical Physics, 2012)
Purpose: To eliminate variation in electrometer calibration results caused by high humidity and suboptimal connectors on the standard capacitors and to implement hardware that prevents overloading of the input stage of electrometers during calibration. Methods: A humidity-controlled cabinet was installed to provide a low-humidity environment for the standard capacitors. All of the coaxial BNC connections were replaced with Triax (TRB) connectors with the exception of the output from the voltage source. A three-stage RC filter with cascaded RC low-pass sections was designed and tested. Results: The installation of the humidity cabinet resulted in a major improvement in the stability and reproducibility of the electrometer calibration system. For the three years since this upgrade, the Ionizing Radiation Standards (IRS) electrometer calibration results have been consistent regardless of the ambient relative humidity in the lab. The connector replacements improved grounding in the calibration circuit. The three-stage filter allows the voltage at the output to rise in an S-shaped waveform, resulting in a smooth rise of the current through the isolation resistor from zero and back again, with no abrupt transition. For the filter design chosen, 99.99 of the charge is delivered within 6 s. Conclusions: A three-way improvement to the calibration measurement system was successful in eliminating the observed variations, resulting in an electrometer calibration measurement system that is unaffected by humidity and allowing reliable year-round calibrations of any electrometer encountered since the implementation of these changes.
Keywords: article; calibration; computer assisted radiotherapy; electric capacitance; equipment; equipment design; humidity; instrumentation; radiometry; reproducibility; sensitivity and specificity; standard; static electricity; Calibration; Electric Capacitance; Equipment Design; Equipment Failure Analysis; Humidity; Radiometry; Radiotherapy, Conformal; Reproducibility of Results; Sensitivity and Specificity; Static Electricity

Comment on "linearization of dose-response curve of the radiochromic film dosimetry system" [Med. Phys. 39 (8), 4850-4857 (2012)] - Bouchard, Hugo; McEwen, Malcolm (Medical Physics, 2012)
Keywords: film dosimeter; human; letter; methodology; standard; Film Dosimetry; Humans

Improved Arabic-to-English statistical machine translation by reordering post-verbal subjects for word alignment - Carpuat, Marine; Marton, Yuval; Habash, Nizar (Machine Translation, 2012)
We study challenges raised by the order of Arabic verbs and their subjects in statistical machine translation (SMT). We show that the boundaries of post-verbal subjects (VS) are hard to detect accurately, even with a state-of-the-art Arabic dependency parser. In addition, VS constructions have highly ambiguous reordering patterns when translated to English, and these patterns are very different for matrix (main clause) VS and non-matrix (subordinate clause) VS. Based on this analysis, we propose a novel method for leveraging VS information in SMT: we reorder VS constructions into pre-verbal (SV) order for word alignment. Unlike previous approaches to source-side reordering, phrase extraction and decoding are performed using the original Arabic word order. This strategy significantly improves BLEU and TER scores, even on a strong large-scale baseline. Limiting reordering to matrix VS yields further improvements.
Keywords: Statistical machine translation; Reordering; VS; Post-verbal subjects; Matrix subject; Subject detection; Word alignment; Dependency parsing

An automatic network-extraction algorithm applied to magnetic survey data for the identification and extraction of geologic lineaments - Lee, Madeline; Morris, William; Harris, Jeff; Leblanc, George (Leading Edge (Tulsa, OK), 2012)
Lineament analysis is commonly undertaken by interpreting a wide range of geoscientific data to delineate geologic structures. These structures include faults, fractures, dykes, and lithological contacts, which provide information for geologic mapping and mineral and energy exploration. We offer a simple automatic lineament analysis method that combines the principles of peak-identification algorithms typically used in geophysical data interpretation and a GIS drainage "network-extraction" algorithm commonly applied to a topographic surface. We apply this network-extraction process to a magnetic surface (grid) rather than a topographic one. The GIS approach calculates the curvature of a surface to determine whether a specific coordinate is at a minimum (trough). A simple quadratic surface is computed for a moving 3 × 3 window to determine if the local surface has the form of a dipping plane (or a trough). Continuity of troughs between adjacent kernels defines lineaments that typically correspond to streamflow pathways when analysis is carried out on a topographic surface. On a magnetic anomaly map surface, network extraction identifies magnetic lows that may represent faults that have undergone magnetite (depletion) alteration, or dykes with predominantly reversed polarity remanence. As network extraction is designed to locate troughs, it is possible to isolate normally magnetized dykes by inverting the values of a magnetic data set by to produce ridges. This modified ridge analysis method is successfully applied to three synthetic data sets, showing that network extraction offers the principal benefits of continuity in solutions to produce polylines (over isolated ridge solutions), automation for consistency and reliability, and optional amplitude thresholding. © 2012 Society of Exploration Geophysicists.
Keywords: Amplitude thresholding; Energy exploration; Geologic mapping; Geologic structures; Geophysical data; Geoscientific data; Lineament analysis; Local surfaces; Magnetic anomalies; Magnetic data; Magnetic surfaces; Magnetic surveys; Polylines; Quadratic surfaces; Ridge analysis; Synthetic datasets; Data processing; Geographic information systems; Geological surveys; Lithology; Magnetic polarity; Reliability analysis

Improvement of color information in the generation of 3D models of real objects using range intensity images - Takahama, Toru; Inomata, Ryo; Terabayashi, Kenji; Umeda, Kazunori; Godin, Guy (Key Engineering Materials, 2012)
Texture mapping on scanned objects, which is the method to map color images on a 3D geometric model measured by a range image sensor, is often used for constructing a realistic 3D model. Color images are affected by the illumination conditions. Therefore, discontinuities of seams occur when simply applying texture mapping. In this paper, we propose a method for correcting the discontinuities using a range intensity image. A range intensity image is a kind of intensity image that is related to the reflectance ratio of the measured points, simultaneously acquired with a range image using an active range sensor. The method estimates the color information that is not affected by the lighting environment using multiple color images and a range intensity image. As a result, the method is effective to construct a 3D model with seamless color images. The effectiveness of the correction method is illustrated by experiments with real-world objects.
Keywords: 3D models; colour image; rage intensity image; texture mapping

A robust optimization approach for real-time multiple source drinking water blending problem - Peng, Wei; Mayorga, Rene V.; Imran, Syed (Journal of Water Supply: Research and Technology - AQUA, 2012)
Although many optimization methods can be applied to real-time multiple source drinking water blending problems, the field still lacks an approach to rapidly produce a robust optimal solution by simultaneously optimizing multiple objectives. This paper develops a fuzzy multiple response surface methodology (FMRSM) to achieve this objective. In the FMRSM, experimental data are fitted to mean response surface models while the residuals (the error between the predicted response of the mean model and the measured data of the real system) are fitted to standard deviation models. Fuzzy linear programming using the min-operator approach is applied to optimize the multiple objectives. Six scenarios are designed based on data from a real-time multiple source drinking water blending operation. The results show the FMRSM is a robust, computationally efficient optimization approach. The FMRSM could be extended to other real-time multi-objective non-linear optimization problems. © IWA Publishing 2012.
Keywords: fuzzy optimization; multi-objective; real-time operation; robust optimum; water quality

Electrochemical testing of ultraporous membranes as separators in mild aqueous supercapacitors - Laforgue, Alexis; Robitaille, Lucie (Journal of the Electrochemical Society, 2012)
Several commercially available separators as well as novel ultraporous electrospun nonwovens were evaluated in mild aqueous supercapacitor cells, using conventional electrochemical techniques. A special laboratory test-cell was designed and fabricated to accurately control the pressure applied to the stack. It was shown that the separator layer not only affects the equivalent series resistance (ESR) of the cell (high frequency range) but has also an influence on its time constant (medium frequency range). Both ESR and time constant were found to be directly proportional to the separator thickness. Higher porosity and higher pore size were found to lead to better performance, especially at higher power demand. The electrospun separators outperformed the other separator structures in a disruptive manner, most probably due to a synergetic effect of higher porosity and higher pore size. © 2012 The Electrochemical Society.
Keywords: Better performance; Electrochemical techniques; Electrochemical testing; Equivalent series resistance; Frequency ranges; Medium-frequency range; Super capacitor; Synergetic effect; Capacitors; Electric resistance; Pore size; Separators

Volume stability of calcium sulfoaluminate phases - Khoshnazar, Rahil; Beaudoin, James J.; Alizadeh, Rouhollah; Raki, Laila (Journal of the American Ceramic Society, 2012)
The volume stability of calcium sulfoaluminate phases exposed to water, lime, and gypsum environments was investigated. The length changes of compacted specimens of synthetic monosulfate and ettringite were monitored in distilled water, lime-saturated water, gypsum-saturated water, and saturated water vapor. The X-ray diffraction analysis was also performed on the samples to assess the changes in the crystalline structure of each phase. Evidence was provided in support of the significant role of dissolution of monosulfate and ettringite, and the leaching of their constituent ions, on the expansion of these phases. © 2012 The American Ceramic Society.
Keywords: Constituent ions; Crystalline structure; Distilled water; Ettringites; Saturated water; Sulfoaluminate; Volume stability; Gypsum; Leaching; X ray diffraction analysis; Lime

Rim-rotor rotary ramjet engine, part 1: structural design and experimental validation - Rancourt, David; Picard, Mathieu; Denninger, Marc; Plante, Jean-Sébastien; Chen, Jihua; Yousefpour, Ali (Journal of Propulsion and Power, 2012)
The rim-rotor rotary-ramjet engine (R4E) is a new propulsion-system design with the potential to significantly improve power density and reduce complexity of conventional gas turbines, thus making it an interesting alternative for future transportation and stationary power systems. This paper presents the structural design and an experiment validation of a proof-of-concept prototype that can sustain 560 m=s (200 krpm) and transient combustion, which is initiated by an integrated-ignition system.Ahigh-strength carbon-polyetheretherketone (PEEK) composite winding is used around the ramjet blades to support the high g load and includes the flame holder. A6.5-cm prototype is spun up to 188 krpm at rim temperature, reaching 473-K for short periods without failure or rotordynamics issues. Several ignitions and high-temperature combustion of 1 s were achieved at 80,000 rpm. High-combustion temperature for 1 s led to the failure of turbine blades. Total and partial failures of the rim rotor demonstrated the concept safety, as all projections were contained without important damage. Copyright © 2012 by the authors. Published by the American Institute of Aeronautics and Astronautics, Inc.
Keywords: Experimental validations; Flame holder; G-loads; High-temperature combustion; Partial failure; Power densities; Proof of concept; Rotor-dynamics; Short periods; Stationary power systems; Turbine blade; Ethers; Structural design; Ignition

Data intensive high energy physics analysis in a distributed cloud - Charbonneau, A.; Agarwal, A.; Anderson, M.; Armstrong, P.; Fransham, K.; Gable, I.; Harris, D.; Impey, R.; Leavett-Brown, C.; Paterson, M.; Podaima, W.; Sobie, R.J.; et al. (Journal of Physics: Conference Series, 2012)
We show that distributed Infrastructure-as-a-Service (IaaS) compute clouds can be effectively used for the analysis of high energy physics data. We have designed a distributed cloud system that works with any application using large input data sets requiring a high throughput computing environment. The system uses IaaS-enabled science and commercial clusters in Canada and the United States. We describe the process in which a user prepares an analysis virtual machine (VM) and submits batch jobs to a central scheduler. The system boots the user-specific VM on one of the IaaS clouds, runs the jobs and returns the output to the user. The user application accesses a central database for calibration data during the execution of the application. Similarly, the data is located in a central location and streamed by the running application. The system can easily run one hundred simultaneous jobs in an efficient manner and should scale to many hundreds and possibly thousands of user jobs. © IOP Publishing Ltd.
Keywords: Batch jobs; Calibration data; Cloud systems; Data intensive; High-throughput computing; Input datas; Running applications; System use; Virtual machines; Physics; High energy physics

Measuring the switching current of a superconducting single electron transistor in a tunable dissipative environment - Meng, S.; Yaraskavitch, L.; Sachrajda, A. S.; Kycia, J. B. (Journal of Physics: Conference Series, 2012)
We experimentally investigated the switching current Isw of a superconducting single electron transistor (sSET), with competitive Josephson coupling energy EJ and charging energy Ec, in an in situ tunable dissipative environment. At low temperature, averaged Isw shows a clear 1e periodic function of gate induced charge on the island. The relative contrast of this oscillation increases when EJ/Ec is lowered. Increasing dissipation reduce the quantum fluctuations of the phase across the sSET, leading to an increased Isw. © Published under licence by IOP Publishing Ltd.
Keywords: Charging energies; Induced charges; Josephson coupling energies; Low temperatures; Periodic function; Quantum fluctuation; Superconducting single-electron transistors; Switching currents; Low temperature effects; Low temperature engineering; Quantum electronics; Superconductivity; Single electron transistors

Attosecond control of electron correlations in one-photon ionization and recombination - Patchkovskii, Serguei; Smirnova, Olga; Spanner, Michael (Journal of Physics B: Atomic, Molecular and Optical Physics, 2012)
Electron-electron interactions in multielectron systems may cause multiple ionic channels to contribute to amplitudes of ionization or radiative recombination, giving rise to interfering pathways to the same final state. These channels are not individually observable in standard weak-field experiments, where they all contribute to the same final-state resolved cross section. We show how one can use strong laser fields to control the timing of electronelectron interactions. We demonstrate that the relative phases of the direct and correlation channels can be manipulated by a strong infrared field, permitting experimental separation of the individual contributions. The control phase can be calibrated using the attosecond streak camera. The required control conditions are achieved at the rising edge of the giant resonance in the Xe atom.
Keywords: Attoseconds; Control phase; Cross section; Final state; Giant resonances; Infrared field; Interfering pathways; Ionic channels; Multielectron system; Radiative recombination; Relative phasis; Strong laser field; Photoionization

Molecular-frame photoelectron angular distributions - Lucchese, Robert R.; Stolow, Albert (Journal of Physics B: Atomic, Molecular and Optical Physics, 2012)

Preconditioning induces tolerance by suppressing glutamate release in neuron culture ischemia models - Tauskela, Joseph S.; Aylsworth, Amy; Hewitt, Melissa; Brunette, Eric; Mealing, Geoffrey A. R. (Journal of Neurochemistry, 2012)
This study determined how preconditioned neurons responded to oxygen-glucose deprivation (OGD) to result in neuroprotection instead of neurotoxicity. Neurons preconditioned using chronically elevated synaptic activity displayed suppressed elevations in extracellular glutamate ([glutamateex]) and intracellular Ca²+ (Ca²+ in) during OGD. The glutamate uptake inhibitor TBOA induced neurotoxicity, but at a longer OGD duration for preconditioned cultures, suggestive of delayed up-regulation of transporter activity relative to non-preconditioned cultures. This delay was attributed to a critically attenuated release of glutamate, based on tolerance observed against insults mimicking key neurotoxic signaling during OGD (OGD-mimetics). Specifically, in the presence of TBOA, preconditioned neurons displayed potent protection to the OGD-mimetics: ouabain (a Na+/K+ ATPase inhibitor), high 55 mM KCl extracellular buffer (plasma membrane depolarization), veratridine (a Na+ ionophore), and paraquat (intracellular superoxide producer), which correlated with suppressed [glutamateex] elevations in the former two insults. Tolerance by preconditioning was reversed by manipulations that increased [glutamateex], such as by exposure to TBOA or GABAA receptor agonists during OGD, or by exposure to exogenous NMDA or glutamate. Pre-synaptic suppression of neuronal glutamate release by preconditioning, possibly via suppressed exocytic release, represents a key convergence point in neuroprotection during exposure to OGD and OGD-mimetics. © 2012 National Research Council Canada. Journal of Neurochemistry © 2012 International Society for Neurochemistry.
Keywords: excitotoxicity; glutamate; neuroprotection; preconditioning; synaptic scaling; tolerance

Development of an analytical microbial consortia method for enhancing performance monitoring at aerobic wastewater treatment plants - Razban, Behrooz; Nelson, Kristina Y.; McMartin, Dena W.; Cullimore, D. Roy; Wall, Michelle; Wang, Dunling (Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering, 2012)
An analytical method to produce profiles of bacterial biomass fatty acid methyl esters (FAME) was developed employing rapid agitation followed by static incubation (RASI) using selective media of wastewater microbial communities. The results were compiled to produce a unique library for comparison and performance analysis at a Wastewater Treatment Plant (WWTP). A total of 146 samples from the aerated WWTP, comprising 73 samples of each secondary and tertiary effluent, were included analyzed. For comparison purposes, all samples were evaluated via a similarity index (SI) with secondary effluents producing an SI of 0.88 with 2.7% variation and tertiary samples producing an SI 0.86 with 5.0% variation. The results also highlighted significant differences between the fatty acid profiles of the tertiary and secondary effluents indicating considerable shifts in the bacterial community profile between these treatment phases. The WWTP performance results using this method were highly replicable and reproducible indicating that the protocol has potential as a performance-monitoring tool for aerated WWTPs. The results quickly and accurately reflect shifts in dominant bacterial communities that result when processes operations and performance change. © 2012 Copyright Taylor and Francis Group, LLC.
Keywords: FAME, microbial consortia, process monitoring, aerobic wastewater treatment

Automatically creating design models from 3D anthropometry data - Wuhrer, Stefanie; Shu, Chang; Bose, Prosenjit (Journal of Computing and Information Science in Engineering, 2012)
When designing a product that needs to fit the human shape, designers often use a small set of 3D models, called design models, either in physical or digital form, as representative shapes to cover the shape variabilities of the population for which the products are designed. Until recently, the process of creating these models has been an art involving manual interaction and empirical guesswork. The availability of the 3D anthropometric databases provides an opportunity to create design models optimally. In this paper, we propose a novel way to use 3D anthropometric databases to generate design models that represent a given population for design applications such as the sizing of garments and gear. We generate the representative shapes by solving a covering problem in a parameter space. Well-known techniques in computational geometry are used to solve this problem. We demonstrate the method using examples in designing glasses and helmets. © 2012 American Society of Mechanical Engineers.
Keywords: 3D anthropometry; 3D models; Covering problems; Design applications; Design models; Digital forms; Manual interaction; Parameter spaces; Anthropometry; Computational geometry; Product design; Three dimensional computer graphics

Similitude study on bending stiffness and behavior of composite tubes - Derisi, Bijan; Hoa, Suong; Hojjati, Mehdi (Journal of Composite Materials, 2012)
A procedure to design a composite tube that matches the flexural stiffness, load-carrying capacity, and energy absorption of an aluminum tube while subjected to bending load is of interest. The large deformation and energy absorption requirements are fulfilled through the progressive failure of the plies of suitable fiber orientations across the thickness of the tube. The layer wise nature of the composite tubes and cylindrical anisotropy, however, has impeded obtaining a simple closed-form solution for calculating the flexural stiffness. Available analytical solutions are mainly a complex set of equations, which should be solved simultaneously. In addition, the boundary and interface conditions between the adjacent plies must be satisfied. This article presents a straightforward simulation technique for this purpose. First, the tube is correlated to a corresponding composite sandwich panel, the flexural stiffness of which is obtained by the classical laminate theory. Then an analogous aluminum sandwich panel is designed and is correlated to a so-called 'equivalent' aluminum tube. The bending stiffness of the composite tube is shown to be the same as that of its equivalent aluminum tube. As a result, a complex problem of cylindrical anisotropy is mapped into a Cartesian coordinate system and solved via the classical laminate theory. The accuracy of the technique is verified by experimental work and analytical solutions. The agreement between the three methods is shown. © 2011 The Author(s).
Keywords: composite tube; flexural stiffness; large deformation; thermoplastics; progressive failure

Series-coupled triple quantum dot molecules - Amaha, Shinichi; Hatano, Tsuyoshi; Izumida, Wataru; Teraoka, Soichiro; Ono, Keiji; Kono, Kimitoshi; Tarucha, Seigo; Aers, Geof; Gupta, James; Austing, Guy (Japanese Journal of Applied Physics, 2012)
We present the electronic properties of a triple quantum dot molecule embedded inside a sub-micron mesa, made from a quadruple-barrier triplequantum- well structure, and surrounded by a single gate electrode. We outline the design principles of the quadruple-barrier triple-quantum-well structure and calculate the energy of the three lowest states as a function of center well thickness. We observe regular and irregular shaped Coulomb diamond regions similar to those for double quantum dot devices. Variation in the Coulomb blockade region shape is introduced by fluctuation in the offset energies between the quantum dots likely associated with device processing and random impurity potential in the material. We also present Coulomb blockade patterns calculated with a constant interaction model for sequential tunneling through the three series-coupled quantum dots. © 2012 The Japan Society of Applied Physics.
Keywords: Coulomb diamonds; Design Principles; Device processing; Double-quantum dot device; Interaction model; Random impurities; Region shape; Sequential tunneling; Single gates; Submicron; Triple quantum; Well structure; Well thickness; Coulomb blockade; Electronic properties; Semiconductor device structures; Semiconductor quantum dots

Impact behavior of thin thermoplastic composites dependant on manufacturing parameters and layup - Wedekind, Max; Khoun, Loleï; Krempl, Peter; Baier, Horst; Hubert, Pascal (International SAMPE Technical Conference, 2012)
The amount of structural application of carbon composites has grown massively in the last years. Carbon composites are known to provide superior performance with regard to their specific strength and stiffness. One of the major drawbacks, limiting the fields of application and defining knock down factors, is their sensitivity for impact damages. Thermoplastic resin systems are known to provide a better performance on impact behavior compared to thermoset resin systems. Within this paper, an investigation on the impact behavior of carbon composite plates with PEEK resin system is presented. The impact performance is derived by measurement of damage size, penetration depth and residual strength. For structural applications, composites provide the possibility to take use of tailored mechanical properties of laminates, like strength and stiffness by defining specific stacking sequences. Since the impact performance is also affected by the layup, different laminate configurations, starting from low in plane stiffness up to high stiffness, were investigated. Particularly for lightweight applications thin laminates are relevant. To provide the capability to determine the post impact compressive strength of thin plates, avoiding premature failure caused by buckling, a modified test bed for compression after impact test has been developed. Furthermore, within this work the influence of different manufacturing parameters on the impact performance and material properties was investigated, thus allowing an optimized manufacturing process with regard to cost and performance.
Keywords: Carbon composite plates; Carbon composites; Compression after impact tests; Damage size; High stiffness; Impact behavior; Impact damages; Impact performance; In-plane stiffness; Laminate configuration; Lightweight application; Manufacturing parameters; Manufacturing process; Material property; Premature failures; Residual strength; Resin systems; Specific strength; Stacking sequence; Structural applications; Thermoplastic composite; Thermoset resin; Thin plate; Buckling; Composite materials; Equipment testing; Exhibitions; Laminates; Manufacture; Plates (structural components); Resins; Thermosets; Stiffness

Enhanced fire resistance of cellulosic fibers for green polymer composites - Ngo, Tri-Dung; Ton-That, Minh-Tan; Hu, Wei (International SAMPE Technical Conference, 2012)
The incorporation of renewable resources in composite materials is a viable means to reduce environmental impact and support sustainability development in the composites industry. Cellulosic fiber polymer composites have received very much attraction for different industrial applications because of its low density and the renewable ability. However, the uses of cellulosic fibers in the composite are limited in many applications that require fire resistance due to their flammability and their low thermal resistance. This paper reports an innovative and sustainable treatment approaches to retard the burning of cellulosic fibers for composite production in which a minimum amount of non-toxic and low cost inorganic chemicals have been used. Different types of reacting minerals and different treatment parameters have been investigated in order to determine the most cost-effective treatment solution. The cellulosic fibers obtained from this approach become self-extinguished while there is no negative effect on fiber strength. The composite with the treated cellulosic fibers also shows their good fire resistance with minor effect on the mechanical properties. Thus this solution will open the door for the use of the cellulosic fibers in composites for applications where fire resistance is an important issue, particularly in aerospace, transportation, and construction.
Keywords: Cellulosic fibers; Cellulose fibers; Different treatments; Fiber strength; Green polymers; Polymer composite; Renewable resource; Sustainable treatments; Composite materials; Composites; Environmental impact; Fire resistance; Thermal resistance; Inorganic chemicals; Mechanical properties

Field study assessment of the performance of displacement air distribution in a canadian school during the heating season - Ouazia, Boualem; Macdonald, Iain; Tardif, Michel; Thompson, Alexandra; Booth, Daniel (International Journal of Ventilation, 2012)
Stratified ventilation systems use a fundamentally different approach to supply heated or cooled air through a building than the 'fully mixed and dilution' ventilation systems found in the majority of non-residential buildings. Stratified air distribution creates a non-uniform environment in terms of temperature and pollutant distribution, and acceptable conditions in the occupied zone. Previous research has shown that this type of system works well for regions where buildings require year-round cooling. However there are a growing number of buildings using this approach in Canada, where buildings require heating during winter months. This paper presents results from a field study conducted in a school equipped with a displacement ventilation system. The results show that the measured contaminant removal efficiency (based on CO 2 measurements) resulting from displacement ventilation in this case is better than that was predicted in previous studies for displacement ventilation under heating operation. In addition, key predictors of thermal comfort (the measured vertical air temperature difference and draft rating at ankle and head height) are also generally within the limits set by applicable ASHRAE standards.
Keywords: stratified ventilation; Contaminant removal; Displacement ventilation system; IAQ; Pollutant distribution; Carbon dioxide; Hot water heating; Thermal comfort

Encounters with vortices in a turbine nozzle passage - Gostelow, J. P.; Mahallati, A.; Carscallen, W. E.; Rona, A. (International Journal of Rotating Machinery, 2012)
Experiments were conducted on the flow through a transonic turbine cascade. Secondary flows and a wide range of vortex types were encountered, including horseshoe vortices, shock-induced passage vortices, and streamwise vortices on the suction surface. In the separation region on the suction surface, a large rollup of passage vorticity occurred. The blunt leading edge gave rise to strong horseshoe vortices and secondary flows. The suction surface had a strong convex curvature over the forward portion and was quite flat further downstream. Surface flow visualization was performed and this convex surface displayed coherent streamwise vorticity. At subsonic speeds, strong von Kármán vortex shedding resulted in a substantial base pressure deficit. For these conditions, time-resolved measurements were made of the Eckert-Weise energy separation in the blade wake. At transonic speeds, exotic shedding modes were observed. These phenomena all occurred in experiments on the flow around one particular turbine nozzle vane in a linear cascade. © 2012 J. P. Gostelow et al.
Keywords: Base pressure; Blade wake; Blunt leading edges; Convex curvatures; Convex surfaces; Energy separations; Flowthrough; Horseshoe vortices; Linear cascade; Passage vortex; Separation regions; Shedding modes; Streamwise vortices; Subsonic speed; Suction surfaces; Surface flow visualization; Time resolved measurement; Transonic speed; Transonic turbine cascade; Turbine nozzles; Flow visualization; Secondary flow; Turbine components; Vorticity; Wakes; Vortex flow

Characterization of the formation of nickel-rich areas in PM steels and their effect on mechanical properties - Tougas, B.; Blais, C.; Larouche, M.; Chagnon, F.; Pelletier, S. (International Journal of Powder Metallurgy, 2012)
Admixed chemical elements may lead to the formation of heterogeneous microstruc-tures in sintered steels. This is due primarily to low bulk-diffusion coefficients at conventional sintering tem peratures. For powder met allurgy (PM) steels, admixed nickel is well known to produce such heterogeneous microstructures where the element is not distributed evenly upon sintering, resulting in the formation of nickel-rich areas (NRAsj. In contrast, the principal mechanisms of nickel diffusion in PM steels are often misunderstood. This work presents a new approach to measure the bulk-diffusion coefficients of nickel in PM steels in order to determine the sintering conditions required to maximize its homogeneity in a steel matrix. Also, the influence of the local concentration of nickel on sintered microstructures is discussed. The characterization approach presented here could be used to characterize the diffusion of other alloying elements in PM steels, either admixed as elemental powders or introduced via master alloys.

Functionalised silica nanoparticles stable in serum-containing medium efficiently deliver siRNA targeting HIV-1 co-receptor CXCR4 in mammalian cells - Kell, Arnold J.; Barnes, Michael L.; Slater, Kathryn; Lavigne, Carole (International Journal of Nano and Biomaterials, 2012)
The development of non-viral DNA delivery systems using nanomaterials has attracted much research interest for its potential in biomedicine. However, for these new nanocarriers to be successfully used in therapeutic applications they have to overcome many barriers. Here, we report the development and characterisation of polyethyleneimine-modified tetramethylrhodamine-doped silica nanoparticles as a vehicle to deliver siRNA in the presence of serum. We have demonstrated that polyethyleneiminemodified tetramethylrhodamine-doped silica nanoparticles bind and protect siRNA against nuclease degradation and facilitate cellular uptake and intracellular delivery of the siRNA in HeLa-derived TZM-bl cells. The nanoparticles can penetrate TMZ-bl cells at concentrations as low as 1 μg/mL and can escape the lysosomal and endosomal cavities. Following delivery, the nanoparticles release active siRNA targeting the co-receptor CXCR4 for HIV-1 to achieve reduction in the targeted mRNA and protein expression. These nanoparticles are also non-toxic for the cells and are capable of carrying out all of these functions in the presence of serum, a characteristic that is critical if such nanoparticles are to be employed in any type of in vivo application. Copyright © 2012 Inderscience Enterprises Ltd.
Keywords: Cellular uptake; CXCR4; Dye-doped silica nanoparticles; HIV-1 co-receptor; Serum-containing medium; siRNA delivery; Drug therapy; Genetic engineering; Nanoparticles; Nanostructured materials; chemokine receptor CXCR4; messenger RNA; nanoparticle; nuclease; polyethyleneimine; silicon dioxide; small interfering RNA; tetramethylrhodamine doped silica nanoparticle; cell viability; cellular distribution; chemical binding; endosome; enzyme degradation; gene silencing; human cell; Human immunodeficiency virus 1; lysosome; mammal cell; nonviral gene delivery system; protein expression; RNA binding; RNA degradation

Mechanical properties of aluminium-copper B206 alloys with iron and silicon additions - Kamga, H. K.; Larouche, D.; Bournane, M.; Rahem, A. (International Journal of Cast Metals Research, 2012)
Mechanical properties of B206 aluminium alloys with additions of iron and silicon were studied to investigate the combined effect of these additions on tensile strengths and ductility. Properties are highly influenced by the iron to silicon ratio and the nominal concentration of the single elements. The best properties were obtained with both a ratio close to one and low concentrations of iron and silicon. Present experimental results show that it is possible to multiply by two or three the present limit of 0·1 wt-%Fe in these alloys at natural aging (T4) and still obtain the minimum of 7% elongation required by the automotive industry. At artificial aging (T7), it will be very difficult however to reach the 7% elongation with ~0·2 wt-%Fe and 0·2 wt-%Si, while this seems impossible with ~0·3 wt-%Fe and 0·3 wt-%Si. It was found that macrosegregation of Cu in the gage section of the ASTM B108 test bars is responsible for an enrichment of 0·8-0·9 wt-%of this element in the test zone. This has produced microstructures saturated in Cu with little Al 2Cu phase remaining after the solution heat treatment. Owing to the low amount of this phase and the round shape of the particles, the remaining Al 2Cu phase did not have a significant impact on the ductility. One benefit of working with a Cu saturated microstructure is that one can estimate the true temperature of the solution heat treatment by conducting a post-analysis of Cu content in the dendrites. This should be helpful to reduce the variability in properties and to improve the temperature distribution in heat treating furnaces.
A. Rahem was affiliated with the NRC Aluminium Technology Centre at time of publication.
Keywords: B206; Intermetallics; Ductility; Macrosegregation; Quality index

Diffractive and subwavelength grating couplers for microphotonic waveguides - Cheben, P.; Schmid, J. H.; Ramos, C. A.; Halir, R.; Zavargo-Peche, L.; Lapointe, J.; Bock, P.; Xu, D.-X.; Janz, S.; Ortega-Monux, A.; Molina-Fernandez, I.; Ma, R.; et al. (ICTON 2012: 14th International Conference on Transparent Optical Networks, 2012)
We review our advances in diffractive and subwavelength grating coupler structures for microphotonic waveguides. We present a subwavelength grating fiber-chip edge coupler with a loss as low as 0.9 dB and with minimal wavelength dependence over a broad wavelength range exceeding 200 nm. We also present fiber-to-chip surface grating couplers based on subwavelength effective medium. The effective medium refractive index is engineered to control the strength of the grating and thereby maximize coupling efficiency, while mitigating back reflections at the same time. We analyze the fabrication tolerances of the coupler, which are of particular relevance for large scale photonic fabrication. Furthermore, we present the first grating coupler for micrometric silicon rib waveguides, which is particularly challenging since the coupler waveguide region is multimode. We experimentally demonstrate grating couplers in 1.5 μm thick silicon ridge waveguides with a coupling efficiency of 2.2 dB and a 3 dB bandwidth of 40 nm. An inverse taper is used to match the fundamental mode of the interconnection waveguide with the optimum grating coupler excitation field, with negligible higher order mode excitation. The coupler was fabricated using i-line stepper lithography and single etch step. © 2012 IEEE.
Keywords: 3 dB bandwidth; Back reflection; Coupling efficiency; Effective medium; Excitation field; Fabrication tolerances; Fundamental modes; Grating couplers; Higher-order modes; I-line steppers; Microphotonic waveguides; Multimodes; Silicon rib waveguides; Single etch; Sub-wave length grating; Sub-wavelength; Surface grating; Wavelength dependence; Wavelength ranges; Fabrication; Refractive index; Ridge waveguides; Transparent optical networks; Waveguides

Methodology for determination of ice management efficiency - Vachon, Guy; Sayed, Mohamed; Kubat, Ivana (International Conference and Exhibition on Performance of Ships and Structures in Ice 2012, ICETECH 2012, 2012)
The paper describes a methodology for evaluating the effectiveness of ice management (IM) operations, which is part of a larger effort aimed at developing efficient IM systems. Ice dynamics simulations are used to determine ice forces on an assumed structure. The simulations examine the role of variables that can be altered by IM operations such as floe size, ice confinement and ice pressure. The results provide means for quantifying the benefits from icebreaking operations, which is a needed input for the design and optimization of IM systems. Ongoing work employs related techniques to determine icebreaking requirements and IM efficiency. Copyright ©2012 ICETECH 12. All rights reserved.
Keywords: Design and optimization; Floe sizes; Ice cover; Ice dynamics; Ice forces; Ice management; Exhibitions; Meteorological problems; Ships; Vehicle performance; Ice

Quantifying ice pressure conditions and predicting the risk of ship besetting - Kubat, Ivana; Babaei, M. Hossein; Sayed, Mohamed (International Conference and Exhibition on Performance of Ships and Structures in Ice 2012, ICETECH 2012, 2012)
The risks of ship besetting under ice pressure are examined. Hindcasts of ice dynamics examine the conditions that led to the besetting of two vessels in the Gulf of St. Lawrence on 9 March 2005. The analysis examines the distributions of potentially significant variables such as pressure (mean normal stress), ridge thickness and strain rates. A criterion for assessing the risk of besetting was then proposed. A preliminary parametric study was also done in order to illustrate a method for predicting the risk of besetting under different ice and environmental forcing conditions. Copyright ©2012 ICETECH 12. All rights reserved.
Keywords: Besetting; Environmental forcing; Hindcasts; Ice dynamics; Normal stress; Parametric study; Pressure conditions; Significant variables; Exhibitions; Risk assessment; Ships; Vehicle performance; Ice

Numerical simulations of ice interaction with a moored structure - Sayed, Mohamed; Kubat, Ivana; Wright, Brian; Iyerusalimskiy, Aleksandr; Phadke, Amal; Hall, Brenda (International Conference and Exhibition on Performance of Ships and Structures in Ice 2012, ICETECH 2012, 2012)
Numerical simulations are carried out to represent the historical data of ice interaction with the Kulluk during the 1980s. Three dimensional simulations include dynamics of the ice cover and the response of the mooring system. The results give modes of ice accumulation, clearing and ice forces. Depth-averaged simulations consider larger zones of the ice cover to examine a range of conditions that were observed during the past operation of the Kulluk in the Beaufort Sea. The simulations evaluate the effects of managed ice cover characteristics such as floe sizes and confinement. Predicted forces are compared to the historical record of measurements. Copyright © 2012 ICETECH 12. All rights reserved.
Keywords: Floe sizes; Historical records; Ice accumulation; Ice forces; Ice interactions; Kulluk; Moored structures; Three dimensional simulations; Computer simulation; Exhibitions; Meteorological problems; Mooring; Numerical models; Ships; Vehicle performance; Ice

Strength and pressure profiles from conical ice crushing experiments - Gudimetla, P. S. Reddy; Colbourne, Bruce; Daley, Claude; Bruneau, Stephen E.; Gagnon, Robert (International Conference and Exhibition on Performance of Ships and Structures in Ice 2012, ICETECH 2012, 2012)
Experimental procedures for obtaining the crushing strength and pressure profiles of cone shaped ice samples are presented. These experiments were conducted as the part of the STePS2 (Sustainable Technology for Polar Ships and Structures) research project at Memorial University, St. John's, Canada. An objective of this project is to study the response of a full size structural grillage for both quasi-static and dynamic ice loading. To prepare for the structural tests, both 1/4 m dia. and 1m dia. conical ice samples are being crushed against a rigid high-resolution pressure panel in quasi-static conditions. Data from the tests on the pressure panel will help to set the conditions for the later quasi-static and dynamic experiments on the steel grillage. Contact pressure profiles are obtained at each time step during the experiments. The pressure profiles obtained reveal the shape and variability of the high pressure zones that develop during ice-structure contact. The paper describes the experimental procedure including; making the ice samples, shaping the samples, crushing tests and data analysis. Preliminary experimental data from both small cones (i.e., 25 cm diameter) and large cones (i.e., 1 m diameter) tests are provided in this paper. Copyright ©2012 ICETECH 12. All rights reserved.
Keywords: Experimental apparatus; Ice loads; Pressure area relationships

Wireless sensor network reliability and security in factory automation: a survey - Islam, Kamrul; Shen, Weiming; Wang, Xianbin (IEEE Transactions on Systems, Man and Cybernetics Part C: Applications and Reviews, 2012)
Industries can benefit a lot from integrating sensors in industrial plants, structures, machinery, shop floors, and other critical places and utilizing their sensing and monitoring power, communicating and processing abilities to deliver sensed information. Proper use of wireless sensor networks (WSNs) can lower the rate of catastrophic failures, and improve the efficiency and productivity of factory operations. Ensuring reliability and providing adequate security in these crucial services provided by WSNs will reinforce their acceptability as a viable and dependable technology in the factory and industrial domain. In this paper, we examine the reliability and security challenges of WSNs and survey their practicality for industrial adoption. We discuss the unique characteristics that distinguish the factory environment from the rest, elaborate on security and reliability issues with their respective solution measures, and analyze the existing WSN architectures and standards. A number of challenges and interesting research issues have emerged from this study and have been reported for further investigation. © 1998-2012 IEEE.
Keywords: Cryptography; Factory automation; Reliability; Security; Wireless sensor networks (WSNs)

Evaluation of high density pixellated crystal blocks with SiPM readout as candidates for PET/MR detectors in a small animal PET insert - Thompson, C. J.; Goertzen, A. L.; Berg, E. J.; Retiere, F.; Kozlowski, P.; Ryner, L.; Stortz, G.; Sossi, V. (IEEE Transactions on Nuclear Science, 2012)
Arrays of silicon photo-multipliers (SiPMs) are good candidates for the readout of detectors in PET/MR inserts due to their high packing density, efficiency, low bias voltage and insensitivity to magnetic fields. We tested two dual-layer blocks of pixellated lutetium oxy-orthosilicate (LYSO) coupled to SensL 4× 4 SiPM arrays in terms of their ability to resolve all elements using resolvability index (RI) defined by the FWHM of the crystal response function divided by the separation. Our crystal blocks had 49 1.67×1.67×6.0 mm 3 crystals on the bottom layer and 36 1.67× 1.67× 4.0 mm 3 crystals in the top layer (offset by 1/2 of the crystal pitch). All 85 crystals were well resolved: RI= 0.46 compared with RI = 0.41 for a conventional pre-clinical PET scanner's block with 40% lower crystal density. A pair of crystal blocks mounted on translation stages scanned a 0.25 mm 22Na source in 60 0.25 mm steps with the detectors angulated as if there were 16 blocks in a ring. The FWHM of the coincidence response function near the centre of the field of view was 1.31 mm and FWTM was 2.7 mm with the detectors separated by 200 mm. © 2012 IEEE.
Keywords: Bottom layers; Crystal block; Crystal density; Crystal response; Dual layer; Field of views; High density; High packing density; Low bias voltage; Lutetium oxyorthosilicate; PET scanner; Pixellated crystals; Pre-clinical; Response functions; Silicon photomultiplier; Small animal PET; Small animal PET scanners; Translation stage; Detectors; Photomultipliers; Polyethylene terephthalates; Positron emission tomography; Separation; Sodium; Silicon detectors

Quantitative radiolabeled biomolecule detection using a functionalized CMOS sensor - Griffin, R. H.; Mozenson, O.; Beking, M.; DeRosa, M. C.; Lopinski, Gregory (Greg); Tarr, N. G. (Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2012 IEEE, 2012)
For the first time a CMOS imager has been used to detect the presence of radiolabeled target biomolecules captured on a functionalized surface. Using aptamer functionalization the system successfully detected 32P labeled adenosine triphosphate (ATP) at concentrations well below those typically associated with fluorescence-based sensor architectures. The system has also demonstrated its amenability to multiplexed biomolecule detection. Geant4, a Monte Carlo toolkit for simulating the passage of radiation through matter, was used to analyze the detector. Radiolabel detection offers the potential for direct quantitative measurement of bound biomolecules which is advantageous compared to the use of fluorescent tags. © 2012 IEEE.
Keywords: Aptamers; Biomolecule detection; CMOS imagers; Geant4; Radiolabel; Adenosinetriphosphate; CMOS integrated circuits; Detectors; Fluorescence; Medical imaging; Nuclear physics; Radioactive tracers; Biomolecules

A field portable neutron spectrometer based on the Bonner Sphere Principles - Dubeau, Jacques; Hakmana Witharana, S. Sanjeewa; Atanackovic, Jovica; Yonkeu, André; Matysiak, Witold; Waker, Anthony J.; Ibrahim, Aslam; Archambault, John Paul (Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2012 IEEE, 2012)
The Bonner Sphere Spectrometer (BSS) has been used since 1960 for the determination of neutron energy spectra ranging from 25 meV to 20 MeV. Although some researchers have taken full sets of Bonner spheres inside nuclear power plants for field measurements, the volume and mass of the whole device have usually limited its use to laboratories and to calibration and reference facilities. The instrument presented here operates under the same principles of the Bonner spheres, except that different amounts of moderator around a thermal neutron detector are configured by adding or removing cylindrical shells. For this reason it is called the Nested Neutron Spectrometer (NNS). Thus, only the mass and volume equivalent to a single Bonner sphere need to be carried in the field. The reconfiguration of the moderator is very quick, leading to a reduced setup time. The instrument can then easily be used in the workplace and the measured spectra allow the calculation of the ambient dose equivalent rate, without the inherent inaccuracies of REM meters. The focus of this paper is the design principles of the NNS, laboratory test results and field measurements. Measurements were obtained using radionuclide neutron sources, mono-energetic neutrons from accelerators and from neutrons around the containment of a nuclear power reactor. Results are very similar for the NNS and BSS, with the former being much easier to use in the field. © 2012 IEEE.
Keywords: Calibration; Neutron detection; Scintillation counters; Ambient dose equivalent rate; Bonner sphere spectrometer; Cylindrical shell; Design Principles; Field measurement; Mono-energetic neutrons; Nuclear power reactors; Thermal neutron detectors; Measurements; Medical imaging; Moderators; Neutron sources; Neutron spectrometers; Nuclear physics; Nuclear power plants; Spectrometers; Spheres

Evaluation of very highly pixellated crystal blocks with SiPM readout as candidates for PET/MR detectors in a small animal PET insert - Thompson, Christopher J.; Goertzen, Andrew L.; Kozlowski, Poitr; Retiere, Fabrice; Stortz, Greg; Sossi, Vesna; Zhang, Xuezhu (Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2012 IEEE, 2012)
Arrays of silicon photo-multipliers (SiPMs) are good candidates for the readout of detectors in PET MR inserts due to their high packing density, efficiency, low bias voltage and insensitivity to magnetic fields. In this study we report the readout performance of SensL SiPM arrays in terms of their ability to resolve all elements of pixellated lutetium oxyorthosilicate (LYSO) crystals their energy resolution, and coincidence response function. Two SensL SPMarray-4 were used as light sensors. Two LYSO crystal blocks consisting of a arrays of 8×8 1.2 mm × 1.2 mm × 6.0 mm crystals on the lower layer and 7×7 1.2 mm × 1.2 mm × 4.0 mm crystals on the upper layer (which is offset by 1/2 the crystal width) were mounted on the SensL arrays. A second study was performed with single layer arrays of 8×8 1.2 mm × 1.2 mm × 10.0 mm crystals. All of the crystals in the dual layer block were easily identified with a peak to valley ratio of 7.2 while the single layer blocks had a peak to valley ratio of 11.2. The crystal dots were more uniformly spaced in the dual layer arrays suggesting that the inter-layer connection affords some useful light sharing. The average energy resolution for all 113 crystals was 16.3±2.3%. The coincidence response to a 0.25 mm Na-22 source in plastic was 0.97 ±0.12 mm for normally incident gamma rays with the detectors 120 mm apart. These results indicate that it should be possible to achieve a spatial resolution of about one millimetre near the center of the field of view. © 2012 IEEE.
Keywords: positron emission tomography; silicon photo-multiplier; small animal PET insert for MRI scanner

Metallic environmental effect on RF-based energy transmission - Liu, Guocheng; Mrad, Nezih; Xiao, George; Li, Zhenzhong; Ban, Dayan (IEEE Antennas and Wireless Propagation Letters, 2012)
Radio frequency (RF)-based energy transmission enables controllable and simultaneous power delivery to wireless sensors. In such applications, RF energy transmission is likely to be affected by highly conductive (metallic) environments. Understanding metal's influence on power delivery will help improve practical implementation. This letter studies the behavior of RF energy transmission in selected scenarios by measuring return loss and peak received power. Visualized energy flow is simulated to obtain the direct picture of such scenarios. The simulation results are consistent with conclusions drawn from experimental results measured using return loss and peak received power. © 2011 IEEE.
Keywords: Antenna, radio frequency (RF), wireless energy transmission, wireless sensor networks

The Listeria monocytogenes serotype 4b autolysin IspC has N-acetylglucosaminidase activity - Ronholm, Jennifer; Wang, Linru; Hayashi, Ikue; Sugai, Motoyuki; Zhang, Zhiyi; Cao, Xudong; Lin, Min (Glycobiology, 2012)
IspC is a novel peptidoglycan (PG) hydrolase that is conserved in Listeria monocytogenes serotype 4b strains and is involved in virulence. The aim of this study was to establish the hydrolytic bond specificity of IspC. Purified L. monocytogenes peptidoglycan was digested by recombinant IspC and the resulting muropeptides were separated by reverse phase high-performance liquid chromatography. The structure of each muropeptide was determined using matrix-assisted laser desorption ionization (MALDI)-time-of-flight mass spectrometry in combination with MALDI-post-source decay mass spectrometry. The structure of muropeptides resulting from IspC-mediated hydrolysis indicated that IspC has N-acetylglucosaminidase activity. These muropeptides also had a high proportion of N-acetylated glucosamine residues. To determine whether IspC is more effective at hydrolysing N-acetylated peptidoglycan than de-N-acetylated peptidoglycan, a peptidoglycan deacetylase (PgdA) in-frame deletion mutant was created. This mutant was shown to have fully N-acetylated peptidoglycan and was more susceptible to hydrolysis by IspC when compared with the partially de-N-acetylated wild-type peptidoglycan. This indicates that IspC is more efficient when hydrolysing a fully N-acetylated peptidoglycan substrate. The finding that IspC acts as an N-acetylglucosaminidase is consistent with its categorization, based on amino acid sequence, as a member of the GH73 family. As with other members of this family, de-N-acetylation seems to be an important mechanism for regulating the activity of IspC. © 2012 The Author.
Keywords: N-acetylglucosaminidase; N-acetylation; IspC; peptidoglycan; Listeria monocytogenes

Unraveling the complexity of deep gas accumulations with three-dimensional multimodal CARS microscopy - Burruss, Robert C.; Slepkov, Aaron D.; Pegoraro, Adrian F.; Stolow, Albert (Geology, 2012)
The origin of natural gas accumulations in thermally mature basins is poorly understood. Unraveling complex contributions from hydrocarbon cracking, mixing, redox alteration, and deeper sources requires analysis of gases trapped during specifi c periods of basin history. Fluid inclusions can provide such samples, but their unambiguous characterization is challenging. Here we show that three-dimensional (3-D) multimodal nonlinear optical microscopy of geologic materials allows mapping and molecular identifi cation of trapped methane and water using coherent anti-Stokes Raman scattering, imaging of crystallographic features using second harmonic generation, and identifi cation of higher hydrocarbons using twophoton excited fl uorescence. Spatially resolved, molecule-specifi c characterization of fl uid inclusions will improve models of natural gas generation, migration, and accumulation. We believe that these broadly applicable methods will potentially transform the characterization of geological materials. © 2012 Geological Society of America.
Keywords: Coherent anti-Stokes Raman scattering; Deep gas; Fluid inclusion; Gas generation; Geological materials; Higher hydrocarbons; Hydrocarbon cracking; Multi-modal; Nonlinear optical microscopy; Origin of natural gas; Spatially resolved; Two-photon excited; C (programming language); Coherent scattering; Methane; Mineralogy; Natural gas; Nonlinear optics; Optical microscopy; Organic compounds; Positive ions; Raman spectroscopy; Three dimensional; Characterization; fluid inclusion; geoaccumulation; hydrocarbon generation; three-dimensional modeling

Broadband 100 GHz Substrate-Integrated Waveguide couplers with irregularly shaped via holes for higher-order mode suppression - Dousset, David; Bornemann, Jens; Daigle, Maxime; Claude, Stéphane; Wu, Ke (Microwave Conference (EuMC), 2012 42nd European, 2012)
This paper introduces a 3 dB and a 23 dB coupler in Substrate-Integrated Waveguide (SIW) technology for future applications in radio astronomy instrumentation. In order to meet the often challenging specifications of such equipment in terms of both operating frequency and bandwidth, via holes of irregular shape are used to suppress higher-order mode excitation commonly observed in waveguide couplers. Prototypes have been manufactured and measured. For the 23 dB SIW coupler, measurements across the 85-115 GHz band show an isolation level higher than 35 dB, an average insertion loss of 3.75 dB, a coupling factor of 27 dB and a reflection coefficient better than -16.7 dB. The phase difference between the direct and coupled ports is 94.3°±2. 3°. In the 83-111 GHz band and in the case of the 3 dB coupler, isolation is higher than 20 dB, insertion losses are 4.2 dB±0.6 dB, and the reflection coefficient is better than -16.6 dB. The phase difference between the direct and coupled ports is 94.2°±2.1°. © 2012 EUROPEAN MICROWAVE ASSOC.
Keywords: Substrate integrated waveguide (SIW) technology, multi-branch couplers, H-plane couplers, millimeter-wave couplers

The unexpected connection: serendipity and human mediation in networked learning - Kop, Rita (Educational Technology and Society, 2012)
Major changes on the Web in recent years have contributed to an abundance of information for people to harness in their learning. Emerging technologies have instigated the need for critical literacies to support learners on open online networks in the mastering of critical information gathering during their learning journeys. This paper will argue that people will have to adapt to using information in a new way and will advocate the movement by learners into and inside information streams on open online networks. Their own control and aggregation of information, preferably through human mediation, should provide information not only relevant to their learning, but also slightly unexpected. We will highlight why this serendipity is important in a learning context and also take three emerging technologies under the loupe; recommenders, RSS and microbloggers,and their effectiveness in supporting serendipitous learning on open online networks. © International Forum of Educational Technology & Society (IFETS).

(Invited) A "cook's tour" of two decades of research into the optical properties of nanostructured silicon materials - Lockwood, David J. (Pits and Pores 5: A Symposium in Honor of David Lockwood, 2012)
Amongst a number of diverse approaches to engineering efficient light emission in silicon nanostructures, one system that has received considerable attention has been Si/SiO2 quantum wells. Engineering such structures has not been easy, because to observe the desired quantum confinement effects, the quantum well thickness has to be less than 5 nm. Nevertheless, such ultra thin structures have now been produced by a variety of techniques. The SiO 2 layers are amorphous, but the silicon layers can range from amorphous through nanocrystalline to single-crystal form. The fundamental band gap of the quantum wells has been measured primarily by optical techniques and strong confinement effects have been observed. A detailed comparison is made between theoretical and experimental determinations of the band gap in Si/SiO2 quantum wells. The review article is prefaced with a historical account of the Pits and Pores Symposium series and a personal academic history of the author. © The Electrochemical Society.
Keywords: Experimental determination; Fundamental band gap; Historical account; Nanostructured silicon; Quantum confinement effects; Silicon nano structures; Strong confinement; Ultra-thin structures; Energy gap; Nanocrystalline silicon; Semiconductor quantum wells; Silicon oxides; Amorphous silicon

Surface layers in alkaline media: nickel hydrides on metallic nickel electrodes - Hall, David S.; Bock, Christina; MacDougall, Barry R. (Corrosion, Passivity, and Energy: A Symposium in Honor of Digby D. Macdonald, 2012)
Hydrogen generation by water electrolysis is a renewable method of producing fuel and industrial feedstock. Ni-based H2-evolution catalysts in alkaline media are low-cost alternatives to the noblemetal- based electrode materials used in acidic media. However, Ni cathodes show a significant decrease in their hydrogen evolution reaction (HER) activity after several hours of electrolysis. We consider the source of electrode deactivation on smooth metallic Ni electrodes by cyclic voltammetry (CV), galvanostatic and potentiostatic polarization, and X-ray diffraction (XRD). Below the reversible hydrogen electrode (RHE) potential, H atoms incorporate deep into the electrode material. Under industrial conditions, i.e., concentrated NaOH/KOH solutions and large cathodic current densities, α-NiHx and β-NiH x can form at the electrode surface. © The Electrochemical Society.
Keywords: Cathodic current density; Hydrogen evolution reactions; Hydrogen generations; Industrial conditions; Industrial feedstock; Potentiostatic polarization; Reversible hydrogen electrodes; Water electrolysis; Cathodes; Corrosion; Cyclic voltammetry; Hydrogen production; X ray diffraction

Food and interaction design: designing for food in everyday life - Comber, Rob; Ganglbauer, Eva; Choi, Jaz Hee-jeong; Hoonhout, Jettie; Rogers, Yvonne; O'Hara, Kenton; Maitland, Julie (CHI '12 Extended Abstracts on Human Factors in Computing Systems, 2012)
Food and interaction design presents an interesting challenge to the HCI community in attending to the pervasive nature of food, the socio-cultural differences in food practices and a changing global foodscape. To design for meaningful and positive interactions it is essential to identify daily food practices and the opportunities for the design of technology to support such practices. This workshop brings together a community of researchers and practitioners in human-food interaction to attend to the practical and theoretical difficulties in designing for human-food interactions in everyday life. Through a practical field study and workshop we explore themes of food experiences, health and wellbeing, sustainability and alternative food cultures. © 2012 Authors.
Keywords: alternative food cultures; Field studies; human-food-interaction; Interaction design; Positive interaction; Wellbeing; Food products; Health; Psychology computing; Sustainable development; Human engineering

Special issue on advances in high temperature joining of materials - Wanjara, Priti; Brochu, Mathieu; Farfard, Mario (Canadian Metallurgical Quarterly, 2012)

Joining of AA1100-16 vol.-%B4C metal matrix composite using laser welding and friction stir welding - Guo, J.; Gougeon, P.; Nadeau, F.; Chen, X.-G. (Canadian Metallurgical Quarterly, 2012)
This work investigated the weldability of AA1100-16B 4C (vol.-%) metal matrix composite using laser welding and friction stir welding (FSW). The microstructure and mechanical properties of joints produced by two welding techniques were compared. For laser welding, a large amount of brittle needle-like phases, together with some residues of B 4C particles were observed in the fusion zone of the joint. The use of Ti filler can improve the microstructure and increase the joint efficiency from 63 to 75%. On the other hand, the FSW, being a solid state welding technique, was interesting as it minimised the formation of brittle intermetallic phases. In addition, the breakage of B 4C particles and the grain refinement of the matrix were observed in the weld zone. The FSW joints show superior mechanical properties than the laser welded joints. Up to 100% joint efficiency can be achieved by FSW for annealed AA1100-16B 4C materials. © 2012 Canadian Institute of Mining, Metallurgy and Petroleum.
Keywords: Friction stir welding; Intermetallic phases; Laser welding; Mechanical properties; Metal matrix composites; Microstructure

Adipose tissue houses different subtypes of stem cells - Stillwell, Chris; Wang, Fei; Xiang, Bo; Deng, Jixian; Kashour, Tarek; Liu, Hongyu; Freed, Darren; Arora, Rakesh C.; Tian, Ganghong (Canadian Journal of Physiology and Pharmacology, 2012)
Adipose tissue stromal fraction (ASF) contains multipotent cells capable of differentiation towards several lineages and may be used for the treatment of various degenerative diseases. However, the multipotent cells within ASF have not been fully characterized. In this study we have attempted to characterize stem cells in the ASF obtained through serial dilution. Five single-cell clones were studied. It was found that the single-cell clones exhibited slight but significant differences in proliferative capacity and differentiation potential. We conclude that ASF houses different subtypes of stem cells.
Keywords: adipose tissue, stem cells, differentiation, proliferation

Characterization of the type III secretion associated low calcium response genes of Vibrio parahaemolyticus RIMD2210633 - Sarty, Darren; Baker, Noel T.; Thomson, Euan L.; Rafuse, Cheryl; Ebanks, Roger O.; Graham, Lori L.; Thomas, Nikhil A. (Canadian Journal of Microbiology, 2012)
Vcio parahaemolyticus T3SS-1 substrates have been identified, although many predicted substrates (based on homologies) remain undetected in secreted fractions and therefore uncharacterized. We have experimentally developed and optimized a secretion assay protocol allowing for reliable and reproducible detection of V. parahaemolyticus T3SS-1 secreted proteins within culture supernatants. The presence of magnesium and absence of calcium were critical factors in promoting type III secretion of protein substrates. Proteomic approaches identified known V. parahaemolyticus secreted effectors in addition to previously unidentified proteins. Isogenic mutants in putative low calcium response genes were generated, and experiments further implicated the genes in secretion and V. parahaemolyticus-mediated host-cell cytotoxicity during infection. These approaches should be valuable towards future detailed genetic and biochemical analyses of T3SS-1 in V. parahaemolyticus.
Keywords: type III secretion, calcium, effector, cytotoxicity

Prediction of lateral spread displacement: data-driven approaches - Liu, Zheng; Tesfamariam, Solomon (Bulletin of Earthquake Engineering, 2012)
Site seismic hazard (SSH) is an integral component of seismic risk assessment of engineered structures. The SSH encompasses the effect of ground shaking, landslide, and liquefaction. Discernment of liquefaction and lateral spreading vulnerability is a complex and nonlinear procedure that is influenced by model and parameter uncertainty. In this study, nine different data-driven models were investigated to predict the lateral spread displacement over a free-face and ground-slope conditions. These models include: multivariate adaptive regression splines, generalized additive model, neural networks, generalized linear model, robust regression, regression tree, support vector machine, projection pursuit, and random forest. The results demonstrate efficacy of the proposed models for lateral spreading estimation and in general, the random forest showed a better prediction. Sensitivity analysis is also performed to identify parameters that contribute to the model variability. © 2012 Crown Copyright.
Keywords: machine learning; Data-driven model; Lateral spread displacements; Non-parametric regression

Infrared optical imaging of matrix metalloproteinases (MMPs) up regulation following ischemia reperfusion is ameliorated by hypothermia - Barber, Philip A.; Rushforth, David; Agrawal, Smriti; Tuor, Ursula I. (BMC Neuroscience, 2012)
Background: We investigated the use of a new MMP activatable probe MMPSense™ 750 FAST (MMPSense750) for in-vivo visualization of early MMP activity in ischemic stroke. Following middle cerebral artery occlusion (MCAO) optical imaging was performed. Near-infrared (NIR) fluorescent images of MMPSense activation were acquired using an Olympus fluorescent microscope, 1.25x objective, a CCD camera and an appropriate filter cube for detecting the activated probe with peak excitation and emission at 749 and 775 nm, respectively. Images were acquired starting at 2 or 24 hours after reperfusion over the ipsilateral and contralateral cortex before and for 3 hours after, MMPSense750 was injected.Results: Increased intensities ipsilaterally were observed following MMPSense750 injection with ischemic injury but not in sham animals. There were significant ipsilateral and contralateral differences at 15 minutes (P <0.05) in early ischemic reperfusion and at time 0 in 24 hours post ischemia (P <0.05) which persisted at 180 minutes in both these groups (P <0.01), but not following sham surgery. The increase in ipsilateral signal intensity was attenuated by hypothermia. These observations corresponded with a significant increase in the total MMP-9 protein levels, 5 and 24 hours following ischemia reperfusion (P <0.05) and their reduction by hypothermia.Conclusions: Matrix-metalloproteinase upregulation in ischemia reperfusion can be imaged acutely in-vivo with NIRF using MMPSense750. Hypothermia attenuated both the optical increase in intensity after MMPSense750 and the increase in MMP-9 protein expression supporting the proof of concept that NIRF imaging using MMPSense can be used to assess potential therapeutic strategies for stroke treatment.
Keywords: gelatinase B; brain cortex; brain ischemia; brain surgery; enzyme activity; fluorescence microscopy; hypothermia; image processing; in vivo study; infrared radiation; middle cerebral artery occlusion; reperfusion injury; Cerebral Cortex; Enzyme-Linked Immunosorbent Assay; Functional Laterality; Infarction, Middle Cerebral Artery; Infrared Rays; Laser-Doppler Flowmetry; Metalloproteases; Molecular Probes; Up-Regulation

Low-intensity pulsed ultrasound-mediated stimulation of hematopoietic stem/progenitor cell viability, proliferation and differentiation in vitro - Xu, Peng; Gul-Uludag, Hilal; Ang, Woon T.; Yang, Xiaoyan; Huang, Min; Marquez-Curtis, Leah; McGann, Locksley; Janowska-Wieczorek, Anna; Xing, James; Swanson, Eric; Chen, Jie (Biotechnology Letters, 2012)
Low-intensity pulsed ultrasound (LIPUS) stimulated the viability, proliferation and differentiation of hematopoietic stem/progenitor cells (HSPC) from fresh and cryopreserved peripheral blood leukapheresis product, as well as cord blood when applied for 10 min each day for 4 days. Cell viability, proliferation and differentiation were assessed on day 5 by viable cell counting, MTS proliferation assay, flow cytometry, and colony-forming unit assay. LIPUS stimulation: (i) enhanced the proliferation of fresh HSPC and maintained the viability of cryopreserved HSPC in vitro; (ii) did not affect the percentage of CD34 + and CD14 + cells; and (iii) enhanced burst-forming unit-erythroid colony formation. Hence, we suggest that this novel LIPUS stimulation approach might enhance the efficacy of clinical transplantation and cellular therapies using HSPC. © 2012 Springer Science+Business Media B.V.

Integration of optical components on-chip for scattering and fluorescence detection in an optofluidic device - Watts, Benjamin R.; Zhang, Zhiyi; Xu, Chang-Qing; Cao, Xudong; Lin, Min (Biomedical Optics Express, 2012)
An optofluidic device is demonstrated with photonic components integrated onto the chip for use in fluorescence and scatter detection and counting applications. The device is fabricated by integrating the optical and fluidic components in a single functional layer. Optical excitation on-chip is accomplished via a waveguide integrated with a system of lenses that reforms the geometry of the beam in the microfluidic channel into a specific shape that is more suitable for reliable detection. Separate counting tests by detecting fluorescence and scattered signals from 2.5 and 6.0 μm beads were performed and found to show detection reliability comparable to that of conventional means of excitation and an improvement over other microchip-based designs. © 2012 Optical Society of America.
Keywords: Fluidic components; Fluorescence detection; Functional layer; Microfluidic channel; On chips; Optical components; Optofluidic devices; Photonic components; Reliable detection; Photoexcitation; Fluorescence

Spray in cross flow of a rotary atomizer - Choi, Seong Man; Yun, Sangsig; Jeong, Han Jin; Corber, Andrew (Atomization and Sprays, 2012)
This paper presents an experimental investigation of fuel sprays generated by a rotary atomizer exposed to a cross flow of air. The effects of two variables, the rotational speed and cross-flow velocity, on the droplet sizes were studied. The rotary atomizer was driven at speeds up to 15,000 rpm with a fuel flow rate of 15 kg/h and cross flow from 10 to 150 m/s. For any given rotational speed, the fuel droplet sizes decreased as the air cross flow increased, reaching an almost constant value of about 8 μm at 150 m/s cross-flow velocity. At cross-flow velocities less than about 50 m/s, the fuel droplet sizes decreased as the rotational speed increased. However, at a cross-flow velocity greater than 100 m/s, the fuel droplet sizes did not changed significantly as the rotational speed increased. Of the two variables studied, each influenced the droplet size differently in a certain cross-flow velocity region. The rotational speed influenced the droplet size at relatively low cross-flow velocity. By exceeding a cross-flow velocity of 75 m/s, the dynamic effect of high-speed cross flow became dominant. This effect can be generalized to the Weber number based on the orifice diameter and the non-dimensional droplet size. In this correlation, the following three distinct spray regimes were identified according to the Weber number based on orifice diameter: rotation dominant, intermediate, and cross flow dominant. © 2012 by Begell House, Inc.
Keywords: Cross flows; Malvern; Rotary atomizers; Spray; Weber numbers; Drops; Fuel systems; Orifices; Speed; Surface mount technology; Flow velocity

Spatial drop behavior of a rotary atomizer in a cross flow - Choi, Seong Man; Yun, Sangsig; Jeong, Han Jin; Corber, Andrew (Atomization and Sprays, 2012)
This paper presents an investigation of the spatial droplet distribution around a rotary atomizer in an air cross flow. The droplet size, velocity, and spray distribution were measured using a phase Doppler particle analyzer system. The spray was photographed using a high-speed camera. The rotary atomizer was driven at speeds of 5000 rpm, 10,000 rpm, and 15,000 rpm. The fuel flow rate was held constant at 15 kg/h, and the air cross-flow velocities varied from 25 m/s to 150 m/s. The overall spray shape was observed to shrink toward the axis of rotation with increasing cross-flow speeds. High-speed visualization showed that the injected ligaments disintegrate into fairly large droplets and spread out in the radial direction at lower cross-flow velocities. At higher cross-flow speeds, the injected ligaments are abruptly deflected and broken up in the downstream direction close to the surface of the atomizer and are mixed with the cross-flow air stream immediately. The axial velocity profile indicates that a strong recirculation zone is formed just below the rotating nozzle. A high tangential velocity is shown to exist close to the injection point. Further downstream, the radial velocity component is shown to be dominant, while the tangential velocity becomes weak. The axial velocities show similar trends for the same cross-flow velocities, as the droplets follow the dominant air stream formed by the cross flow regardless of rotational speed. Near the injection orifice, relatively larger droplets are concentrated in a narrow region close to the radius of the atomizer. As the liquid jet travels downstream, the droplets are dispersed by the cross flow and distributed over a wider area. The cross flow influences the Sauter mean diameter directly; however, the rotational speed of the nozzle only has a large effect on the spray at slower cross-flow conditions. This injector design is shown to have a circumferential uniformity of ±4 μm, making it an acceptable choice for combustion applications. © 2012 by Begell House, Inc.
Keywords: Cross flows; High-speed visualization; PDPA; Phase Doppler particle analyzer; Rotary atomizers; Sauter mean diameter (SMD); Spray; Tangential velocities; Atomizers; Computational fluid dynamics; Drops; Flow velocity; Surface mount technology; Spray nozzles

Submillimeter polarization of Galactic clouds: a comparison of 350 μm and 850 μm data - Vaillancourt, John E.; Matthews, Brenda C. (The Astrophysical Journal: Supplement Series, 2012)
The Hertz and SCUBA polarimeters, working at 350 μm and 850 μm, respectively, have measured the polarized emission in scores of Galactic clouds. Of the clouds in each data set, 17 were mapped by both instruments with good polarization signal-to-noise ratios. We present maps of each of these 17 clouds comparing the dual-wavelength polarization amplitudes and position angles at the same spatial locations. In total number of clouds compared, this is a four-fold increase over previous work. Across the entire data set real position angle differences are seen between wavelengths. While the distribution of φ(850)-φ(350) is centered near zero (near-equal angles), 64% of data points with high polarization signal-to-noise (P ≥ 3σ p) have |φ(850)-φ(350)| > 10°. Of those data with small changes in position angle (≤10°) the median ratio of the polarization amplitudes is P(850)/P(350) = 1.7 ± 0.6. This value is consistent with previous work performed on smaller samples and models that require mixtures of different grain properties and polarization efficiencies. Along with the polarization data we have also compiled the intensity data at both wavelengths; we find a trend of decreasing polarization with increasing 850-to-350 μm intensity ratio. All the polarization and intensity data presented here (1699 points in total) are available in electronic format. © 2012. The American Astronomical Society. All rights reserved.

On the central helium-burning variable stars of the LeoI dwarf spheroidal galaxy - Fiorentino, G.; Stetson, P. B.; Monelli, M.; Bono, G.; Bernard, E. J.; Pietrinferni, A. (The Astrophysical Journal Letters, 2012)
We present a study of short-period, central helium-burning variable stars in the Local Group dwarf spheroidal galaxy LeoI, including 106 RR Lyrae stars and 51 Cepheids. So far, this is the largest sample of Cepheids and the largest Cepheids to RR Lyrae ratio found in such a kind of galaxy. Comparison with other Local Group dwarf spheroidals, Carina and Fornax, shows that the period distribution of RR Lyrae stars is quite similar, suggesting similar properties of the parent populations, whereas the Cepheid period distribution in LeoI peaks at longer periods (P ∼ 1.26days instead of ∼0.5days) and spans over a broader range, from 0.5 to 1.78days. Evolutionary and pulsation predictions indicate, assuming a mean metallicity peaked within -1.5 ≲ [Fe/H] ≲ -1.3, that the current sample of LeoI Cepheids traces a unique mix of anomalous Cepheids (blue extent of the red-clump, partially electron-degenerate central helium-burning stars) and short-period classical Cepheids (blue-loop, quiescent central helium-burning stars). Current evolutionary prescriptions also indicate that the transition mass between the two different groups of stars is M HeF ∼2.1 M ⊙, and it is constant for stars metal-poorer than [Fe/H] ∼-0.7. Finally, we briefly outline the different implications of the current findings on the star formation history of LeoI. © 2012. The American Astronomical Society. All rights reserved.

The small-scale physical structure and fragmentation difference of two embedded intermediate-mass protostars in Orion - van Kempen, T.A.; Longmore, S. N.; Johnstone, D.; Pillai, T.; Fuente, A. (The Astrophysical Journal, 2012)
Intermediate-mass (IM) protostars, the bridge between the very common solar-like protostars and the more massive, but rarer, O and B stars, can only be studied at high physical spatial resolutions in a handful of clouds. In this paper, we present and analyze the continuum results from an observing campaign at the Submillimeter Array (SMA) targeting two well-studied IM protostars in Orion, NGC2071 and L1641 S3 MMS 1. The extended SMA (eSMA) probes structure at angular resolutions up to 02, revealing protostellar disks on scales of 200AU. Continuum flux measurements on these scales indicate that a significant amount of mass, a few tens of M ⊙, is present. Envelope, stellar, and disk masses are derived using compact, extended, and eSMA configurations and compared against spectral energy distribution fitting models. We hypothesize that fragmentation into three components occurred within NGC2071 at an early time, when the envelopes were less than 10% of their current masses, e.g., <0.5 M ⊙. No fragmentation occurred for L1641 S3 MMS 1. For NGC2071, evidence is given that the bulk of the envelope material currently around each source was accreted after the initial fragmentation. In addition, about 30% of the total core mass is not yet associated to one of the three sources. A global accretion model is favored and a potential accretion history of NGC2071 is presented. It is shown that the relatively low level of fragmentation in NGC2071 was stifled compared to the expected fragmentation from a Jeans argument. Similarly, the lack of fragmentation in L1641 S3 MMS 1 is likely due to similar arguments. © 2012. The American Astronomical Society. All rights reserved..

Different evolutionary stages in the massive star-forming region W3 main complex - Wang, Yuan; Beuther, Henrik; Zhang, Qizhou; Bik, Arjan; Rodón, Javier A.; Jiang, Zhibo; Fallscheer, Cassandra (The Astrophysical Journal, 2012)
We observed three high-mass star-forming regions in the W3 high-mass star formation complex with the Submillimeter Array and IRAM 30m telescope. These regions, i.e., W3 SMS1 (W3 IRS5), SMS2 (W3 IRS4) and SMS3, are in different evolutionary stages and are located within the same large-scale environment, which allows us to study rotation and outflows as well as chemical properties in an evolutionary sense. While we find multiple millimeter continuum sources toward all regions, these three subregions exhibit different dynamical and chemical properties, which indicate that they are in different evolutionary stages. Even within each subregion, massive cores of different ages are found, e.g., in SMS2, sub-sources from the most evolved ultracompact H II region to potential starless cores exist within 30,000 AU of each other. Outflows and rotational structures are found in SMS1 and SMS2. Evidence for interactions between the molecular cloud and the H II regions is found in the 13CO channel maps, which may indicate triggered star formation. © 2012. The American Astronomical Society. All rights reserved..

Size of the Vela pulsar's emission region at 18 cm wavelength - Gwinn, C. R.; Johnson, M. D.; Reynolds, J. E.; Jauncey, D. L.; Tzioumis, A. K.; Hirabayashi, H.; Kobayashi, H.; Murata, Y.; Edwards, P. G.; Dougherty, S.; Carlson, B.; del Rizzo, D.; et al. (The Astrophysical Journal, 2012)
We present measurements of the linear diameter of the emission region of the Vela pulsar at observing wavelength λ = 18 cm. We infer the diameter as a function of pulse phase from the distribution of visibility on the Mopra-Tidbinbilla baseline. As we demonstrate, in the presence of strong scintillation, finite size of the emission region produces a characteristic W-shaped signature in the projection of the visibility distribution onto the real axis. This modification involves heightened probability density near the mean amplitude, decreased probability to either side, and a return to the zero-size distribution beyond. We observe this signature with high statistical significance, as compared with the best-fitting zero-size model, in many regions of pulse phase. We find that the equivalent FWHM of the pulsar's emission region decreases from more than 400 km early in the pulse to near zero at the peak of the pulse and then increases again to approximately 800 km near the trailing edge. We discuss possible systematic effects and compare our work with previous results. © © 2012. The American Astronomical Society. All rights reserved..

Noise in the cross-power spectrum of the Vela pulsar - Gwinn, C. R.; Johnson, M. D.; Reynolds, J. E.; Jauncey, D. L.; Tzioumis, A. K.; Dougherty, S.; Carlson, B.; Del Rizzo, D.; Hirabayashi, H.; Kobayashi, H.; Murata, Y.; Edwards, P. G.; et al. (The Astrophysical Journal, 2012)
We compare the noise in interferometric measurements of the Vela pulsar from ground- and space-based antennas with theoretical predictions. The noise depends on both the flux density and the interferometric phase of the source. Because the Vela pulsar is bright and scintillating, these comparisons extend into both the low and high signal-to-noise regimes. Furthermore, our diversity of baselines explores the full range of variation in interferometric phase. We find excellent agreement between theoretical expectations and our estimates of noise among samples within the characteristic scintillation scales. Namely, the noise is drawn from an elliptical Gaussian distribution in the complex plane, centered on the signal. The major axis, aligned with the signal phase, varies quadratically with the signal, while the minor axis, at quadrature, varies with the same linear coefficients. For weak signal, the noise approaches a circular Gaussian distribution. Both the variance and covariance of the noise are also affected by artifacts of digitization and correlation. In particular, we show that gating introduces correlations between nearby spectral channels. © © 2012. The American Astronomical Society. All rights reserved..

The young open clusters King 12, NGC 7788, and NGC 7790: pre-main-sequence stars and extended stellar halos - Davidge, T. J. (The Astrophysical Journal, 2012)
The stellar contents of the open clusters King 12, NGC 7788, and NGC 7790 are investigated using MegaCam images. Comparisons with isochrones yield an age <20 Myr for King 12, 20-40 Myr for NGC 7788, and 60-80 Myr for NGC 7790 based on the properties of stars near the main-sequence turnoff (MSTO) in each cluster. The reddening of NGC 7788 is much larger than previously estimated. The luminosity functions (LFs) of King 12 and NGC 7788 show breaks that are attributed to the onset of pre-main-sequence (PMS) objects, and comparisons with models of PMS evolution yield ages that are consistent with those measured from stars near the MSTO. In contrast, the r′ LF of main-sequence stars in NGC 7790 is matched to r′ = 20 by a model that is based on the solar neighborhood mass function. The structural properties of all three clusters are investigated by examining the two-point angular correlation function of blue main-sequence stars. King 12 and NGC 7788 are each surrounded by a stellar halo that extends out to a radius of 5 arcmin (∼3.4 pc). It is suggested that these halos form in response to large-scale mass ejection early in the evolution of the clusters, as predicted by models. In contrast, blue main-sequence stars in NGC 7790 are traced out to a radius of ∼7.5 arcmin (∼5.5 pc), with no evidence of a halo. It is suggested that all three clusters may have originated in the same star-forming complex, but not in the same giant molecular cloud. © 2012. The American Astronomical Society. All rights reserved..

Deep Hubble Space Telescope imaging in NGC 6397: stellar dynamics - Heyl, J. S.; Richer, H.; Anderson, J.; Fahlman, G.; Dotter, A.; Hurley, J.; Kalirai, J.; Rich, R. M.; Shara, M.; Stetson, P.; Woodley, K. A.; Zurek, D. (The Astrophysical Journal, 2012)
Multi-epoch observations with the Advanced Camera for Surveys on the Hubble Space Telescope provide a unique and comprehensive probe of stellar dynamics within NGC 6397. We are able to confront analytic models of the globular cluster with the observed stellar proper motions. The measured proper motions probe well along the main sequence from 0.8 to below 0.1 M as well as white dwarfs younger than 1 Gyr. The observed field lies just beyond the half-light radius where standard models of globular cluster dynamics (e.g., based on a lowered Maxwellian phase-space distribution) make very robust predictions for the stellar proper motions as a function of mass. The observed proper motions show no evidence for anisotropy in the velocity distribution; furthermore, the observations agree in detail with a straightforward model of the stellar distribution function. We do not find any evidence that the young white dwarfs have received a natal kick in contradiction with earlier results. Using the observed proper motions of the main-sequence stars, we obtain a kinematic estimate of the distance to NGC 6397 of 2.2+0.5 - 0.7 kpc and a mass of the cluster of 1.1 ± 0.1 × 105 M at the photometric distance of 2.53 kpc. One of the main-sequence stars appears to travel on a trajectory that will escape the cluster, yielding an estimate of the evaporation timescale, over which the number of stars in the cluster decreases by a factor of e, of about 3 Gyr. The proper motions of the youngest white dwarfs appear to resemble those of the most massive main-sequence stars, providing the first direct constraint on the relaxation time of the stars in a globular cluster of greater than or about 0.7 Gyr. © 2012. The American Astronomical Society. All rights reserved..

A new reddening law for M4 - Hendricks, Benjamin; Stetson, Peter B.; VandenBerg, Don A.; Dall'Ora, Massimo (The Astronomical Journal, 2012)
We have used a combination of broadband near-infrared and optical Johnson-Cousins photometry to study the dust properties in the line of sight to the Galactic globular cluster M4. We have investigated the reddening effects in terms of absolute strength and variation across the cluster field, as well as the shape of the reddening law defined by the type of dust. All three aspects had been poorly defined for this system and, consequently, there has been controversy about the absolute distance to this globular cluster, which is closest to the Sun. Here, we determine the ratio of absolute to selective extinction (R V) in the line of sight toward M4, which is known to be a useful indicator for the type of dust and therefore characterizes the applicable reddening law. Our method is independent of age assumptions and appears to be significantly more precise and accurate than previous approaches. We obtain A V /E(B - V) = 3.76 ± 0.07 (random error) for the dust in the line of sight to M4 for our set of filters. That corresponds to a dust-type parameter R V = 3.62 ± 0.07 in the Cardelli et al. reddening law. With this value, the distance to M4 is found to be 1.80 ± 0.05 kpc, corresponding to a true distance modulus of (m - M) 0 = 11.28 ± 0.06 (random error). A reddening map for M4 has been created, which reveals a spatial differential reddening of δE(B - V) ≥ 0.2 mag across the field within 10′ around the cluster center; this is about 50% of the total mean reddening, which we have determined to be E(B - V) = 0.37 ± 0.01. In order to provide accurate zero points for the extinction coefficients of our photometric filters, we investigated the impact of stellar parameters such as temperature, surface gravity, and metallicity on the extinction properties and the necessary corrections in different bandpasses. Using both synthetic ATLAS9 spectra and observed spectral energy distributions, we found similarly sized effects for the range of temperature and surface gravity typical of globular cluster stars: each causes a change of about 3% in the necessary correction factor for each filter combination. Interestingly, variations in the metallicity cause effects of the same order when the assumed value is changed from the solar metallicity ([Fe/H] = 0.0) to [Fe/H] = -2.5. The systematic differences between the reddening corrections for a typical main-sequence turnoff star in a metal poor globular cluster and a Vega-like star are even stronger (5%). We compared the results from synthetic spectra to those obtained with observed spectral energy distributions and found significant differences for temperatures lower than 5000 K. We have attributed these discrepancies to the inadequate treatment of some molecular bands in the B filter within the ATLAS9 models. Fortunately, these differences do not affect the principal astrophysical conclusions in this study, which are based on stars hotter than 5000K. From our calculations, we provide extinction zero points for Johnson-Cousins and Two Micron All Sky Survey filters, spanning a wide range of stellar parameters and dust types. These extinction tables are suited for accurate, object-specific extinction corrections. © 2012. The American Astronomical Society. All rights reserved.

Contaminant removal effectiveness of displacement ventilation systems during heating season: summary results from three field studies - Ouazia, Boualem; Thompson, Alexandra; Macdonald, Iain; Booth, Daniel; Tardif, Michel (ASHRAE Transactions, 2012)
A series of field studies on the performance of displacement ventilation (DV) were carried out in schools across Canada during the heating season over the last three years. Indoor air quality was evaluated using the IAQ index Contaminant Removal Effectiveness (CRE) based on carbon dioxide concentrations for three schools equipped with DV systems. Results from the three field studies have shown values of CRE to be higher than 0.7 (ventilation effectiveness specified in ASHRAE 62.1-2007 when DV systems are used for heating, with ceiling return). The measured CRE in the three schools was often greater than 1.0 even in the middle of the heating season. The results show that as long as the supply air is cooler than the room air, DV system works well in achieving good contaminant stratification and ventilation effectiveness in the space when combined with a perimeter heating system. ©2012 ASHRAE.
Keywords: Carbon dioxide concentrations; Contaminant removal; Displacement ventilation; Displacement ventilation system; Field studies; Heating season; Heating system; Indoor air quality; Room air; Ventilation effectiveness; Carbon dioxide; Heating; Indoor air pollution; Societies and institutions; Ventilation

Thermopiezoelectric response of a one-dimensional functionally graded piezoelectric medium to a moving heat source-a review - Chen, Zengtao; Akbarzadeh, Hamid; Babaei, Hossein (New trends in mechatronics and materials engineering: selected, peer reviewed papers from the 2011 international conference on mechatronics and materials engineering (ICMME 2011), 2012)
The multi-physics of piezoelectric materials under different environmental conditions has been an active research subject for a few decades. Particularly, the thermoelastic behaviour of smart materials and structures is of great importance to their reliability in different applications. Traditionally, the Fourier heat conduction theory was introduced in dealing with the thermoelastic reactions of smart materials and structures. This may lead to reasonable analyses and useful guidelines in design of smart structures, especially when no severe thermal gradient is involved. However, when a severe thermal gradient is indeed involved in the service environment of a smart structure, the analysing results based on the Fourier heat conduction theory is unrealistic and usually rendered useless. Non-Fourier heat conduction theories have been introduced in the thermoelastic analysis of smart materials and structures in recent years and resulted in reasonable results. In this paper, we review the recent results of a thermopiezoelectric problem of a one-dimensional (1-D), finite length, functionally graded medium excited by a moving heat source using both the Fourier and Non-Fourier heat conduction theories. Numerical examples are displayed to illustrate the effects of non-homogeneity index, length and thermal relaxation time on the results. © (2012) Trans Tech Publications, Switzerland.
Keywords: Environmental conditions; Finite length; Fourier heat conduction; Functionally graded; Moving heat sources; Multi-physics; Non-Fourier heat conduction theory; Nonhomogeneity; Numerical example; Piezoelectric medium; Research subjects; Service environment; Smart materials and structures; Thermal relaxation time; Thermoelastic analysis; Thermoelastics; Thermopiezoelectric; Functionally graded materials; Heat conduction; Intelligent materials; MEMS; Piezoelectric materials; Thermal gradients; Thermal stress; Thermoelasticity; Fourier transforms

Vibration analysis based feature extraction for bearing fault detection - Liu, Jie; Yang, Chunsheng; Lou, Qingfeng (Applied sciences and engineering: modern topics in manufacturing and designing: selected, peer reviewed papers from the International conference on mechanical science and engineering (ICMSE 2012), 2012)
Rolling element bearings are widely used in various rotary machines. Most rotary machine failures are attributed to unexpected bearing faults. Accordingly, reliable bearing fault detection is critically needed in industries to prevent these machines' performance degradation, malfunction, or even catastrophic failures. Feature extraction plays an important role in bearing fault detection and significant research efforts have thus far been devoted to this subject from both academia and industry. This paper intends to provide a brief review of the recent developments in feature extraction for bearing fault detection, and the focus will be placed on the advances in methods for dealing with the nonstationary characteristics of bearing fault signatures. © (2012) Trans Tech Publications, Switzerland.
Keywords: Bearing fault detection; Bearing fault signature; Catastrophic failures; Health condition; Nonstationary; Performance degradation; Research efforts; Rolling Element Bearing; Rotary machine; Bearings (structural); Condition monitoring; Fault detection; Rotating machinery; Signal processing; Vibration analysis; Feature extraction

Next-generation sequencing of microbial communities in the athabasca river and its tributaries in relation to oil sands mining activities - Yergeau, Etienne; Lawrence, John R.; Sanschagrin, Sylvie; Waiser, Marley J.; Korber, Darren R.; Greer, Charles W. (Applied and Environmental Microbiology, 2012)
The Athabasca oil sands deposit is the largest reservoir of crude bitumen in the world. Recently, the soaring demand for oil and the availability of modern bitumen extraction technology have heightened exploitation of this reservoir and the potential unintended consequences of pollution in the Athabasca River. The main objective of the present study was to evaluate the potential impacts of oil sands mining on neighboring aquatic microbial community structure. Microbial communities were sampled from sediments in the Athabasca River and its tributaries as well as in oil sands tailings ponds. Bacterial and archaeal 16S rRNA genes were amplified and sequenced using next-generation sequencing technology (454 and Ion Torrent). Sediments were also analyzed for a variety of chemical and physical characteristics. Microbial communities in the fine tailings of the tailings ponds were strikingly distinct from those in the Athabasca River and tributary sediments. Microbial communities in sediments taken close to tailings ponds were more similar to those in the fine tailings of the tailings ponds than to the ones from sediments further away. Additionally, bacterial diversity was significantly lower in tailings pond sediments. Several taxonomic groups of Bacteria and Archaea showed significant correlations with the concentrations of different contaminants, highlighting their potential as bioindicators. We also extensively validated Ion Torrent sequencing in the context of environmental studies by comparing Ion Torrent and 454 data sets and by analyzing control samples. © 2012, American Society for Microbiology.
Keywords: 16S rRNA gene; Aquatic microbial communities; Archaea; Archaeal; Athabasca; Athabasca oil sands; Bacterial diversity; Bitumen extraction; Environmental studies; Microbial communities; Oil sands mining; Oil sands tailings; Tailings pond; Bituminous materials; Microorganisms; Oil sands; Ore tailings; RNA; Sedimentology; sediments; RNA 16S; bioindicator; fluvial deposit; physicochemical property; prokaryote; river pollution; species diversity; archaeon; bacterium; biodiversity; DNA sequence; environmental monitoring; genetics; high throughput sequencing; microbial consortium; microbiology; oil and gas field; oil spill; water pollutant; Oil and Gas Fields; Petroleum Pollution; Rivers; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Water Pollutants, Chemical; Alberta; Athabasca River; Canada; Archaea; Bacteria (microorganisms)

Subjective fidelity assessment of rotorcraft training simulators - Timson, Emma; Perfect, Philip; White, Mark; Padfield, Gareth D.; Erdos, Robert; Gubbels, Arthur W. (68th American Helicopter Society international annual forum 2012 : Fort Worth, Texas, USA, 1-3 May 2012., 2012)
This paper describes the potential applications of a Simulation Fidelity Rating (SFR) scale, to support the subjective assessment of rotorcraft training simulators. In this paper, the SFR scale has been used to examine pilot sensitivity and subsequent task strategy adaptation to simulator transport delay variations in the Precision Hover manoeuvre. The current FAA AC 120-63 and JAR-FSTD H simulator qualification standards requires a transport delay of no more than 100ms to meet the most stringent Level D criteria. The study has highlighted that the majority of the evaluation pilots indicated that transport delays of this order would compromise the utility of the simulator to provide training for the Precision Hover manoeuvre. For an additional 100ms transport delay, the pilot's SFRs ranged from Level 1 fidelity (simulation fit for purpose) to Level 3 fidelity (simulation not fit for purpose). The factors influencing the SFRs awarded, and their impact on the application of the SFR scale, are discussed in this paper. The methodology detailed in this paper has potential for more objective quantification of the utility of rotorcraft training simulators. Copyright ©2012 by the American Helicopter Society Inc. All rights reserved.
Keywords: Level-1; Potential applications; Qualification standards; Simulation fidelity; Subjective assessments; Task strategy; Training simulator; Transport delay; Helicopter rotors; Helicopters; Rotors; Simulators

The atomic structure of deuterated boyleite ZnSO4·4D2O, ilesite MnSO4·4D2O, and bianchite ZnSO4·6D2O - Anderson, Jennifer L.; Peterson, Ronald C.; Swainson, Ian (American Mineralogist, 2012)
Deuterated boyleite ZnSO 44D 2O, was synthesized and the atomic structure, including D positions, was successfully refined in a combined histogram neutron diffraction refinement. The cell dimensions for boyleite are a = 5.9144(2), b = 13.5665(4), c = 7.8924(2) Å, and β = 90.668(2)° with space group P2 1/n and Z = 4. The atomic structure including D positions of the isostructural mineral ilesite, MnSO 4·4D 2O, was refined and the cell dimensions are a = 5.9753(1), b = 13.8186(3), c = 8.0461(1) Å, and β = 90.826(2)°. Deuterated bianchite ZnSO 4·6D 2O was synthesized and the atomic structure, including D positions, was successfully refined with a unit cell of a = 9.969(1), b = 7. 2441(7), c = 24.249(3) Å, and β = 98.488(5)° in space group C2/c and Z = 8. A comparison of the hydrogen bonding in M 2+SO 4·4D 2O with that in M 2+SO 4·6D 2O shows that bifurcated hydrogen bonds are common in the tetrahydrate sulfates but nonexistent in the hexahydrate structures. This is a result of the packing constraints of the rings of the sulfate and metal-containing octahedra in the tetrahydrates. In the hexahydrate sulfates there is no direct linkage between the sulfate and metal-containing octahedra and hydrogen bonds are optimized without packing constraints, and no bifurcated hydrogen bonds are observed.
Keywords: chemical bonding; crystal structure; crystallography; neutron diffraction; sulfate group

A hybrid fuzzy logic proportional-integral-derivative and conventional on-off controller for morphing wing actuation using shape memory alloy: part 1, morphing system mechanisms and controller architecture design - Grigorie, T. L.; Botez, R. M.; Popov, A. V.; Mamou, M.; Mébarki, Y. (The Aeronautical Journal, 2012)
The present paper describes the design of a hybrid actuation control concept, a fuzzy logic proportional-integral-derivative plus a conventional on-off controller, for a new morphing mechanism using smart materials as actuators, which were made from shape memory alloys (SMA). The research work described here was developed for the open loop phase of a morphing wing system, whose primary goal was to reduce the wing drag by delaying the transition (from laminar to fully turbulent flows) position toward the wing trailing edge. The designed controller drives the actuation system equipped with SMA actuators to modify the flexible upper wing skin surface. The designed controller was also included, as an internal loop, in the closed loop architecture of the morphing wing system, based on the pressure information received from the flexible skin mounted pressure sensors and on the estimation of the transition location. The controller's purposes were established following a comprehensive presentation of the morphing wing system architecture and requirements. The strong nonlinearities of the SMA actuators' characteristics and the system requirements led to the choice of a hybrid controller architecture as a combination of a bi-positional on-off controller and a fuzzy logic controller (FLC). In the chosen architecture, the controller would behave as a switch between the SMA cooling and heating phases, situations where the output current is 0A or is controlled by the FLC. In the design phase, a proportional-integral-derivative scheme was chosen for the FLC. The input-output mapping of the fuzzy model was designed, taking account of the system's error and its change in error, and a final architecture for the hybrid controller was obtained. The shapes chosen for the inputs' membership functions were s-function, π-function, and z-function, and product fuzzy inference and the center average defuzzifier were applied (Sugeno).
Keywords: Actuation systems; Closed loop architecture; Controller architectures; Defuzzifiers; Design phase; Fuzzy logic controllers; Fuzzy models; Hybrid actuation; Hybrid controller; Input-output mapping; Internal loops; Morphing; Morphing wings; Open loops; Output current; Proportional integral derivatives; S-function; Skin surfaces; SMA actuators; Strong nonlinearity; System architectures; Transition locations; Wing trailing edge; Fuzzy logic; Membership functions; Microactuators; Proportional control systems; Shape memory effect; Flexible wings

A hybrid fuzzy logic proportional-integral-derivative and conventional on-off controller for morphing wing actuation using shape memory alloy: part 2, controller implementation and validation - Grigorie, Teodor Lucian; Botez, Ruxandra Mihaela; Popov, Andrei Vladimir; Mamou, Mahmoud; Mébarki, Youssef (The Aeronautical Journal, 2012)
The paper presents the numerical and experimental validation of a hybrid actuation control concept - fuzzy logic proportional-integral-derivative (PID) plus conventional on-off - for a new morphing wing mechanism, using smart materials made of shape memory alloy (SMA) as actuators. After a presentation of the hybrid controller architecture that was adopted in the Part 1, this paper focuses on its implementation, simulation and validation. The PID on-off controller was numerically and experimentally implemented using the Matlab/Simulink software. Following preliminary numerical simulations which were conducted to tune the controller, an experimental validation was performed. To implement the controller on the physical model, two programmable switching power supplies (AMREL SPS100-33) and a Quanser Q8 data acquisition card were used. The data acquisition inputs were two signals from linear variable differential transformer potentiometers, indicating the positions of the actuators, and six signals from thermocouples installed on the SMA wires. The acquisition board's output channels were used to control power supplies in order to obtain the desired skin deflections. The experimental validation utilised an experimental bench test in laboratory conditions in the absence of aerodynamic forces, and a wind-tunnel test for different actuation commands. Simultaneously, the optimised aerofoils were experimentally validated with the theoreticallydetermined aerofoils obtained earlier. Both the transition point real time position detection and visualisation were realised in wind tunnel tests.
Keywords: Aerodynamic forces; Controller implementation; Data acquisition cards; Experimental bench; Experimental validations; Hybrid actuation; Hybrid controller; Laboratory conditions; Linear variable differential transformer; Matlab/Simulink software; Morphing wings; Output channels; Physical model; Position detection; Power supply; Proportional integral derivatives; Simulation and validation; SMA wire; Switching power supplies; Transition point; Wind tunnel tests; Actuators; Aerodynamics; Data acquisition; Electric power supplies to apparatus; Fuzzy logic; Power electronics; Shape memory effect; Thermocouples; Visualization; Voltage dividers; Proportional control systems

Exploring how social media can enhance the teaching of action research - Carroll, Fiona; Jenkins, Alyson; Woodward, Clare; Kop, Rita; Jenkins, Emrys (Action Research, 2012)
Action research has an extensive history of being used to improve teaching and learning in many different professional settings, for example, schools, colleges, universities health and social care services. Educational action research embodies a process that necessitates honesty and openness and which lends itself to the betterment of one's practice; in the current e-learning climate, where education is rapidly changing and the role and practice of the educator is evolving yet uncertain, action research has never been more valuable. This article explores and presents how social media have been used to enhance the teaching of action research and also how students gained an understanding, appreciation and an evolving experience of action research. Exploring the intricate relationships between action research, new technologies and the learning that took place during an Understanding Action Research module, this article is written from the perspective that the module team was interested in ensuring that students acquired a fully rounded understanding of action research in order to utilize it in the improvement of their own practice. © The Author(s) 2011 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

The flight dynamics of Tapejara, a pterosaur from the early cretaceous of Brazil with a large cranial crest - Chatterjee, Sankar; Templin, R. Jack (Acta Geologica Sinica - English Edition, 2012)
Tapejara wellnhoferi, a small azhdarchoid pterodactyloid from the Early Cretaceous Santana Formation of Brazil, provides critical information about the aerodynamic function of its spectacular head crest. The cranial crests in pterodactyloids were sexually dimorphic and are thought to have evolved in adult males in response to female mate choice. However, the location of cranial crests in front of the center of gravity would create instability in the yaw axis during flight and may seem like a handicap. Vertically aligned webbed feet probably suppressed the yawing rotations and instability from the crest. Here we show that the crest functioned as a front rudder to make agile turn and mediate flight control. A computer simulation model suggests that Tapejara had a large excess of muscle power available above the power required for continuous flapping flight. It could easily takeoff from a perch, ground, or water surface and land safely on the ground. It was an excellent glider with a gliding angle close to 4° and a cruising speed of 27 km/h. Tapejara could soar efficiently on the windward side of cliffs or circle on rising thermals over tropical waters for efficient long-distance flight. Various control surfaces in the wings of Tapejara analogous to the slat, aileron, elevator, fin, rudder, and horizontal stabilizer of an aircraft made pterodactyloids versatile flyers.
Keywords: aerodynamics; cliff; computer simulation; Cretaceous; feather; female behavior; flight activity; functional morphology; gravity field; mate choice; paleontology; pterosaur; sexual dimorphism; wing morphology; Brazil; Pterodactyloidea; Tapejara

A comparative study on mechanical and electrical properties of SWCNT-modified epoxy resins and their end-use applications - Ashrafi, Behnam; Jakubinek, Michael B.; Martinez-Rubi, Yadienka; Simard, Benoit; Johnston, Andrew (53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference 2012, 2012)
In this work, the influence of SWCNTs on electrical and mechanical performance of two epoxy resins was studied. In the first study, a small quantity of SWCNTs (0.125 wt%) was incorporated into a high-temperature aerospace-grade epoxy. After the modification with SWCNTs, the correlation between bulk properties of this epoxy (electrical conductivity and Mode I fracture toughness) and the properties of epoxy/glass fiber laminates (inplane/ transverse electrical conductivity and Mode I interlaminar fracture toughness) was investigated. It was found that the electrical property improvements of nano-modified laminates exceeded those of bulk SWCNT-modified epoxy. On the other hand, the fracture toughness improvement of bulk epoxy after the addition of SWCNTs did not translate into interlaminar properties enhancement, possibly due to reduction of the nano-modified resin's ability to interact with glass fiber mats. In the second study, the mechanical and electrical performance of a SWCNT-modified epoxy adhesive was studied for aluminum-to-aluminum bonding. It was found that the integration of 1 wt% SWCNTs can considerably improve joint Mode I fracture toughness by ~ 35% due to mechanisms such as crack bridging. The electrical resistance of the bondline was also consistent with the electrical conductivity of SWCNT-modified adhesive films (~10-3 S/m), but somewhat lower than the bulk electrical conductivity measured on thicker samples. © 2012 by Canada National Research Council.
Keywords: Electrical conductivity; Electrical resistances; Interlaminar fracture toughness; Interlaminar properties; Mechanical and electrical; Mechanical and electrical properties; Mechanical performance; Mode-i fracture toughness; Aluminum; Epoxy resins; Fracture toughness; Resins; Structural dynamics; Electric conductivity

Thermocapillary migration of a deformable droplet - Samareh, B.; Mostaghimi, J.; Moreau, C. (6th International Conference on Thermal Engineering Theory and Applications, 2012)
In the present study a parallel three dimensional Volume of Fluid (VOF) method is developed to simulate Marangoni force in immiscible fluids with variable surface tension. Conservation equations are solved based on cell-averaged one-field volume tracking scheme. Evaluating the convective term in the energy equation along the boundary between the fluids highly depends on the position and orientation of the interface; hence, using average cell values simply ignores the interface shape and leads to computational uncertainty. As a remedy to this issue, the original idea behind the volume tracking method is used not only to advect mass and momentum but also energy across cells. To verify the proposed algorithm, results are compared against theoretically predicted thermocapillary migration velocity of a droplet at the limit of zero Marangoni number. However, at relatively high Marangoni numbers, thermal boundary layers are very thin and challenging to resolve. To demonstrate the capabilities of the heat transfer module, simulation of a Fluorinert droplet moving in silicon oil under applied temperature gradient in microgravity is compared against the available experimental results and the migration velocity of the droplet is reported.
Keywords: Computational uncertainties; Conservation equations; Energy equation; Fluorinert; Immiscible fluids; Interface shape; Interfacial heat transfer; Marangoni force; Marangoni numbers; Migration velocity; Silicon oil; Thermal boundary layer; Thermocapillary migration; Three-dimensional volume; Tracking scheme; Variable surface tension; Volume tracking method; Capillary flow; Heat transfer; Surface tension; Thermoanalysis; Drops

Particle size effects on ice crystal accretion - Knezevici, Daniel C.; Fuleki, Dan; Currie, Tom C.; MacLeod, James D. (4th AIAA Atmospheric and Space Environments Conference 2012, 2012)
This paper describes the commissioning of a new test apparatus intended to simulate an inner-compressor duct bleed slot. It also identifies, for the first time, that ice crystal particle size plays an important role in the ice crystal phenomenon. Data and sample images of accretion are presented for wet bulb temperatures near freezing. The effect of wet bulb temperature and particle size on the natural melting of ice crystals is investigated. In addition, the erosion of surface accretion by ice crystal particles is discussed. © 2012 by Her Majesty the Queen in Right of Canada. Published by the American Institute of Aeronautics and Astronautics, Inc.
Keywords: Ice crystals; Particle size effect; Test apparatus; Wet bulb temperature; Particle size; Phase transitions; Ice

Wake vortex encounter aircraft and underwing pod loads - Brown, Anthony P. (4th AIAA Atmospheric and Space Environments Conference 2012, 2012)
THE NRC CT-133 aircraft has been used for wake turbulence research, over a period of five years. More recently, underwing sensor pod development has been completed, for the conduct of jet aircraft emission flight research, with the intention of being able to fully measure various aspects of emissions holistically, over the whole of the aircraft wake regimes. Critical airworthiness issues included the loads that the aircraft and pods would be subjected to, in the wake turbulence regimes of wakes, and the trailing-pair wake vortex regime in particular. NRC CT-133 wake turbulence data without the pods has been analysed and transformed to the pod CG locations, and resulting reactions derived for the pod mounting rack attachment bolt locations, the critical loading points. The resulting pod mounting rack attachment bolt loads have been parametrically related for wake turbulence parameters. When installed, the pods were fitted with accelerometers and accelerations measured, from which loads have been derived. These loads have been compared with those estimated for wake vortex encounter data without the pods. The pods mounting bolts loads were within the airworthiness safety limit. © 2012 by The Crown in Right of Canada. Published by the American Institute of Aeronautics and Astronautics, Inc.
Keywords: Aircraft emissions; Aircraft wakes; Critical loading; Flight research; Pod development; Safety limits; Wake turbulence; Wake vortex; Aircraft; Atmospheric thermodynamics; Bolts; Loading; Mountings; Turbulence; Wakes

Aviation emissions index derivation methodologies from flight data, including black carbon and aerosols - Brown, Anthony P.; Bastian, Matthew; Smallwood, Greg; O'Brien, Jason (4th AIAA Atmospheric and Space Environments Conference 2012, 2012)
The NRC has undertaken aviation emissions flight research. Principally aimed at Heavy and Super Jet Transports, the project has applied the NRC T-33 to measure condensation nuclei (CN), black carbon (BC), volatile organic compounds (VOC) and oxides of nitrogen (NOy) from aircraft flying enroute at high altitude. Most recently, the T-33 and flight profiles, developed under the research, have been applied to the comparative measurement of jet biofuel emissions. During the course of the project, techniques have been developed, for the derivation of estimated Emission Indices (EI) of pollutant species, measured on the ground (during taxy, departure or arrival runway operations) or inflight. In particular, if the jet engine exhaust jet streams were very young, air temperature measurements were used to correlate to empirically modeled turbulent jet mixing fluid dynamics, thereby deriving the applicable dilution factors (DF) to apply to the measured concentrations. For exhaust plumes which were not very young (i.e. not in a state of turbulent mixing, but rather in a state of turbulent or quiescent diffusion), flight data has involved techniques for the full cross-sectional measurement of wakes, including jet wake and wake vortex regimes. Not only has this captured the nature of wake structures under very strong static and dynamic influences, but permitted the measurement of aerosol emission index numbers directly. © 2012 by The Crown in Right of Canada. Published by the American Institute of Aeronautics and Astronautics, Inc.
Keywords: Aerosol emissions; Air temperature measurement; Comparative measurements; Condensation nuclei; Oxides of nitrogen; Pollutant species; Runway operations; Volatile organic compound (VOC); Aerosols; Aviation; Exhaust systems (engine); Jet engines; Temperature measurement; Volatile organic compounds; Wakes; Atmospheric thermodynamics

Fundamental study of mixed-phase icing with application to ice crystal accretion in aircraft jet engines - Currie, Thomas C.; Struk, Peter M.; Tsao, Jen-Ching; Fuleki, Dan; Knezevici, Daniel C. (4th AIAA Atmospheric and Space Environments Conference 2012, 2012)
This paper describes experiments performed in an altitude chamber at the National Research Council of Canada (NRC) as the first phase of a joint NRC/NASA program investigating ice crystal accretion in aero engines. The principal objective was to explore the effect of wet bulb temperature Twb (dependent on air temperature, humidity and pressure) on accretion behavior, since preliminary results published in an earlier paper indicated that well-adhered accretions are only possible at Twb<0°C, when water in an impinging mixedphase flow can freeze to a surface. To assess the accretion sensitivity to Twb, the symmetrical airfoil used in the previous work was tested at pressures of 44.8 kPa and 93kPa, usually at 0.25 Mach number, over a range of freestream liquid water and ice water concentrations, total air temperatures and humidity levels. Twb was typically maintained at +2°C or -2°C, based on dry total conditions (i.e. without ice or water injection). Total air temperature was >0°C in all tests. The limited test results confirmed that accretion behavior is very sensitive to Twb, which is in turn strongly related to pressure since evaporative cooling increases with decreasing pressure. Humidity and total temperature did not appear to have an independent effect on accretion behavior. Accretions, often resembling glaze ice, formed at Twb<0°C, when freestream water would freeze on the test airfoil without ice crystals present in the freestream. At Twb>0°C ice deposits were observed to be slushy, poorly adhered and shed frequently. The size of such deposits appeared to be a non-linear function of the freestream ice water content (IWC), becoming much larger at high IWC. © 2012 by National Research Council of Canada. Published by the American Institute of Aeronautics and Astronautics, Inc.
Keywords: Aircraft jet engines; Evaporative cooling; Fundamental studies; Ice water content; National Research Council of Canada; Nonlinear functions; Total temperatures; Wet bulb temperature; Airfoils; Atmospheric humidity; Atmospheric temperature; Deposits; Evaporative cooling systems; Functions; Jet engines; Ice

Inflight cold-soaked fuel frost observations and analysis - Brown, Anthony P. (4th AIAA Atmospheric and Space Environments Conference 2012, 2012)
Observations of occurrences of inflight cold-soaked fuel frost (CSFF) on the wings of jet transport aircraft are presented and discussed, together with weather observational records. Although potentially rare occurrences, it would appear that such inflight frost deposition is not unique. Nor are the aerodynamic characteristics of jet transport wings protected in any way, from the roughness effect of inflight frost deposition. © 2012 by The Crown in Right of Canada. Published by the American Institute of Aeronautics and Astronautics, Inc.
Keywords: Aerodynamic characteristics; Frost deposition; Jet transports; Roughness effects; Deposition; Transport aircraft

Icing wind tunnel tests of a contaminated supercritical anti-iced wing section during simulated take-off - Phase 2 - Clark, Catherine; MacMaster, Marc (4th AIAA Atmospheric and Space Environments Conference 2012, 2012)
Icing wind tunnel tests were conducted at the National Research Council Canada's 3 m x 6 m Propulsion and Icing Wind Tunnel (PIWT) located in Ottawa, Ontario, Canada early in 2011 and 2012. These tests were a continuation of the work performed in 2010 on a generic supercritical airfoil representative of a regional-jet type aircraft wing section. Tests nominally consisted of coating the wing with de/anti-icing fluid, applying various levels of precipitation (e.g., snow, ice pellets, freezing rain, or combinations thereof), and simulating a take-off condition in the wind tunnel by accelerating the wind speed and pitching the wing through a desired pitch-profile. The wing performance was evaluated primarily by the measured lift-loss relative to the lift generated by a clean wing. The second phase of testing consisted of test cases similar to the 2010 tests in order to expand the scope of the data sets at various temperatures, while also investigating the effects of the rotation speed and ramp time on lift-loss and the effects of fluids and precipitation on stall. The experimental results were used as guidance for regulators in determining holdover and allowance times for aircraft operating in winter precipitation. © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
Keywords: Freezing rain; National Research Council; Ontario , Canada; Rotation speed; Supercritical; Supercritical airfoils; Wind tunnel tests; Winter precipitation; Rain; Takeoff; Wind stress; Wings; Wind tunnels

Trailing vortex formation by lifting-line field induction and centrifugal stability analyses - Brown, Anthony P. (4th AIAA Atmospheric and Space Environments Conference 2012, 2012)
Analyses of Wake Vortex formation and downstream development have been conducted, using mutual field induction calculations of the shed vorticity sheet. In order to illustrate and compare the formation and downstream development of wingtip vortices, the analyses were conducted for two widely-different cases of spanwise distribution of bound-vorticity. Termed inboard and outboard distributions, the loadings were nearly triangular and rectangular, respectively. For development analysis, Biot-Savart field calculations were conducted for the induced velocity field, and hence displacement of the elements of the shed vorticity sheet. Although an induced field calculation does not represent all fluid-element forces (in particular, the expansion pressure field) and thus, might over-estimate core radius for example), the comparative calculations provided results of interest, regarding the properties of developed wingtip vortices, such as core radius, span location, core asymmetry and peak velocity location. Following this and with reference to the NRC flight measurements of small, intense vortex elements with peaks greater than potential vortex peaks, centrifugal stability analysis is conducted, using a number of models: (1) the developed vortices for the outboard loading case were stimulated with, and released from, radial forcing; (2) a physical model of the centrifugal balance between inertia and pressure forces was examined by time-wise solution of the equations of elemental equations of motion, and (3) the Euler equations in axisymmetric, cylindrical coordinate form were numerically, spatiotemporally solved for excess-velocity vortex profiles. An example of resultant radial flow behaviour is compared to flight data. © 2012 by The Crown in Right of Canada. Published by the American Institute of Aeronautics and Astronautics, Inc.
Keywords: Centrifugal stabilities; Cylindrical coordinates; Expansion pressure; Field calculation; Flight measurements; Induced velocity; Potential vortex; Spanwise distribution; Centrifugation; Euler equations; Loading; Velocity; Vorticity; Vortex flow

Enroute flight data of wake vortex core profiles and properties from yawed traverses - Brown, Anthony P.; Bastian, Matthew (4th AIAA Atmospheric and Space Environments Conference 2012, 2012)
Over the period 2006 to 2012, the NRC enroute wake vortex flight research project has measured vortex core profiles and properties, during numerous traverses of the vortex cores generated by Heavy and Super Category jet transports, flying enroute in cruise. The vortex core traverses were conducted by the NRC T-33 and were all initiated in-trail, with the T-33 flight-path being parallel to the vortex core axis generally vortex core entries were made in the vortex core six o-clock position. Core traverses took 3/4 to 11/4 seconds, over which the T-33 flew along the vortex axis a distance of 200-300 metres, and 4-20 m across the cores, amounting to traverse angles of 2-4° The vortex core profile symmetry and/or constancy over such a small traverse angle was ascertained, by comparing the advancing and retreating segments (to the closest point-of-approach, CPA) of the profiles. Often the implied symmetry/constancy was good, sometimes it wasn't small, very energetic secondary and tertiary vortex segments were encountered only to or from the CPA, on either the advancing or retreating segment only. In particular, they made identification of vortex core funnel segments difficult. In 2011, yaw traverses of vortex cores were conducted, entering the cores at angles of yaw to the vortex axial direction, of 1530° and/or angles of pitch of c.5° so that the cores were traversed over much smaller axial distances than intrail traverses. The analyses of the flight data from these yaw core-traverses is presented. © 2012 by The Crown in Right of Canada. Published by the American Institute of Aeronautics and Astronautics, Inc.
Keywords: Axial direction; Axial distance; Flight data; Flight research; Jet transports; Tertiary vortex; Vortex axis; Vortex cores; Flight paths; Wakes; Vortex flow

On reducing low frequency impact sound transmission in wood framed construction - Zeitler, Berndt; Sabourin, Ivan; Schoenwald, Stefan; Wenzke, Erik (41st International Congress and Exposition on Noise Control Engineering 2012 (INTER-NOISE 2012), 2012)
In an effort to generate design details for wood framed construction that meet the very stringent Korean Code requirements, solutions to reduce low frequency impact sound were developed. This paper presents these design details and the approach taken to develop them, which involved a parametric study of direct impact sound insulation followed by a flanking study. Results of the direct sound insulation study focus on the effects of topping and ceiling designs, whereas the flanking study focuses on the significance of flanking on the overall impact sound transmission between two rooms, one above the other, and on how a topping affects direct and flanking impact sound transmission differently. Copyright © (2012) by the Institute of Noise Control Engineering (INCE).
Keywords: Code requirements; Direct impact; Impact sound; Impact sound transmissions; Parametric study; Acoustic wave transmission; Acoustic waves; Architectural acoustics; Design; Wooden construction

Classification and effect of floor treatment on wood frame construction - Zeitler, Berndt; Schoenwald, Stefan; King, Frances (41st International Congress and Exposition on Noise Control Engineering 2012 (INTER-NOISE 2012), 2012)
Several recent NRC studies have investigated the change of sound insulation of lightweight framed floors, due to the addition of floor treatments (toppings and coverings). In this paper, a method to classify floor treatments as globally reacting or locally reacting is presented. A floor treatment that is locally reacting affects only the injected power and not the propagation of structure-borne sound to and through a junction. In this case, the floor treatment affects direct and all flanking sound transmission paths the same, for all path directions. A globally reacting floor treatment affects sound transmission in different paths differently, since it alters both the power injected, and the path itself. In this study lightweight wood frame floors were considered, where for globally reacting floor treatments, orientation of the floor treatment relative to the joists orientation are important parameters for their effectiveness. Several floor treatments (two toppings and six coverings) were measured and classified as locally or globally reacting, and effects are compared. Most of the floor treatments improved sound insulation, but two worsened it.
Keywords: Flanking sounds; Injected power; Sound transmission; Structure borne sound; Wood frame; Wood frame construction; Acoustic wave transmission; Architectural acoustics; Floors

Innovative moisture/icing-resistant flush air data system - Hui, Kenneth (28th Congress of the International Council of the Aeronautical Sciences 2012 (ICAS 2012), 2012)
Bombardier Aerospace contracted the Flight Research Laboratory of the National Research Council of Canada (NRC) to develop a Flush Air Data System (FADS) capable of operation following transit through adverse weather conditions for use on Bombardier's test aircraft. The NRC's existing FADS design was modified to incorporate water traps at the inlet of each of the four pressure ports to prevent moisture ingestion into the pressure lines. A heating system was designed to reduce moisture condensation in the pressure lines. After fabrication of the final prototype was completed, experimental bench tests were performed to demonstrate that the FADS had met the performance requirements for flight through adverse conditions and that the system was safe for flight. The FADS was then sent to Bombardier Flight Test Centre and installed on a Bombardier Global 5000 aircraft for flight testing. To evaluate the FADS performance, manoeuvres were performed where the FADS was exposed to adverse weather conditions; the FADS angle of attack and angle of sideslip measurements were unaffected by these conditions during the tests. The FADS was calibrated using NRC's GPS-based Simultaneous Calibration of Air Data Systems (SCADS) technique by developing angle of attack and angle of sideslip calibration coefficients. The calibration coefficients were then validated across the aircraft's flight envelope and weather requirements. From the results of the bench tests and flight tests, it was concluded that the new FADS was able to measure angles of attack and sideslip after flight through adverse weather conditions accurately. © NRC Canada 2012.
Keywords: Air data; Bombardier aerospaces; Calibration coefficients; Flush air data systems; Moisture condensation; National Research Council of Canada; Performance requirements; Simultaneous calibration; Angle of attack; Angle of attack indicators; Calibration; Meteorology; Moisture; Research laboratories; Aircraft

Numerical simulations of self-sustained aeroelastic oscillations at low Reynolds numbers - Yuan, Weixing; Wang, Baoyuan; Poirel, Dominique (28th Congress of the International Council of the Aeronautical Sciences 2012 (ICAS 2012), 2012)
By coupling a two-degree-of-freedom structural model with an in-house incompressible code, numerical simulations were performed for a NACA 0012 airfoil undergoing self-sustained oscillations. As observed in experiments, the numerical simulations confirmed the presence of the pitch-heave limit-cycle oscillations of the airfoil at transitional Reynolds numbers, as a result of the nonlinear low-Re aerodynamics. The computed results revealed that the pitch motion of the pitch-heave limit-cycle oscillations at Rec < 80,000 was mainly maintained by the pitching moment feeding energy from the flow to the airfoil, while the pitch motion is believed to be sustained through the coupling with the second degree of freedom in heave at Rec > 80,000. Both pitch and heave motions were bounded by the pitching moment at ultimate pitch angles to a limit-cycle oscillation.
Keywords: Aeroelastic oscillations; Degree of freedom; Limit cycle oscillations; Low Reynolds number; Low-Reaerodynamics; Self-sustained oscillations; Structural models; Two-degree-of-freedom; Aerodynamics; Airfoils; Computer simulation; Model structures; Reynolds number; Aeroelasticity

Paraphrasing for style - Xu, Wei; Ritter, Alan; Dolan, William B.; Grishman, Ralph; Cherry, Colin (COLING 2012, 24th International Conference on Computational Linguistics, Proceedings of the Conference: Technical Papers, 2012)
We present initial investigation into the task of paraphrasing language while targeting a particular writing style. The plays of William Shakespeare and their modern translations are used as a testbed for evaluating paraphrase systems targeting a specific style of writing. We show that even with a relatively small amount of parallel training data, it is possible to learn paraphrase models which capture stylistic phenomena, and these models outperform baselines based on dictionaries and out-of-domain parallel text. In addition we present an initial investigation into automatic evaluation metrics for paraphrasing writing style. To the best of our knowledge this is the first work to investigate the task of paraphrasing text with the goal of targeting a specific style of writing. © 2012 The COLING.
Keywords: Automatic evaluation; Parallel text; Parallel training; Paraphrase; Shakespeare; Writing style; Computational linguistics

A benchmark analysis of Canadian clean technology commercialization accelerators - Malek, Kourosh; Maine, Elicia; McCarthy, Ian (PICMET '12 : Portland International Center for Management of Engineering and Technology, proceedings, Technology Management for Emerging Technologies, 2012)
Although the size of the Canadian clean energy market is small, high R&D capacity and clean-tech ventures delivering emerging clean energy technologies could potentially make Canada a global leader in supplying direct products, services and infrastructure to clean energy markets. Technology commercialization centres are of vital importance in facilitating and accelerating the transfer of academic and applied research to create and support technology-based ventures. However, there is a lack of clarity around the governance, performance, operation, and business model of such organizations. In order to develop and implement the best business practices for Clean Energy Commercialization Accelerators (CECAs), this paper explores different business operational models which were adopted by different non-profit clean energy commercialization organizations. A two-stage approach was employed. In the first stage, over fifteen organizations (including twelve non-profit organizations and three university research parks) in Canada, the U.S., and Europe were selected for benchmark analysis. Four distinct business operational models emerge based upon an in-depth analysis: incubation focused, technology-enabled, market-enabled, and strategic partnership. Thereafter, a typology of organizations is proposed, based on four discriminating models: governance, finance, operation, and revenue. This typological analysis is then employed to unravel best business practices for CECAs, in view of governance structure, management practice, community impacts, overall business model and performance, strategic plan, and operation. © 2012 IEEE..
Keywords: Applied research; Benchmark analysis; Business models; Business practices; Clean energy; Clean energy technology; Clean technologies; Direct product; Governance structures; In-depth analysis; Management practices; Non profit organizations; Non-profit; Operational model; Strategic partnership; Strategic plan; Technology commercializations; Technology-based; University research; Commerce; Industrial management; Profitability; Societies and institutions; Technology

Ecological validity and the evaluation of speech summarization quality - McCallum, Anthony; Penn, Gerald; Munteanu, Cosmin; Zhu, Xiaodan (Spoken Language Technology Workshop (SLT), 2012 IEEE, 2012)
There is little evidence of widespread adoption of speech summarization systems. This may be due in part to the fact that the natural language heuristics used to generate summaries are often optimized with respect to a class of evaluation measures that, while computationally and experimentally inexpensive, rely on subjectively selected gold standards against which automatically generated summaries are scored. This evaluation protocol does not take into account the usefulness of a summary in assisting the listener in achieving his or her goal. In this paper we study how current measures and methods for evaluating summarization systems compare to human-centric evaluation criteria. For this, we have designed and conducted an ecologically valid evaluation that determines the value of a summary when embedded in a task, rather than how closely a summary resembles a gold standard. The results of our evaluation demonstrate that in the domain of lecture summarization, the well-known baseline of maximal marginal relevance [1] is statistically significantly worse than human-generated extractive summaries, and even worse than having no summary at all in a simple quiz-taking task. Priming seems to have no statistically significant effect on the usefulness of the human summaries. This is interesting because priming had been proposed as a technique for increasing kappa scores and/or maintaining goal orientation among summary authors. In addition, our results suggest that ROUGE scores, regardless of whether they are derived from numerically-ranked reference data or ecologically valid human-extracted summaries, may not always be reliable as inexpensive proxies for task-embedded evaluations. In fact, under some conditions, relying exclusively on ROUGE may lead to scoring human-generated summaries very favourably even when a task-embedded score calls their usefulness into question relative to using no summaries at all. © 2012 IEEE.
Keywords: Automatically generated; Ecological validity; Evaluation criteria; Evaluation measures; Evaluation protocol; Goal orientations; Gold standards; Human-centric; NAtural language processing; Natural languages; Reference data; Speech summarization; Summarization systems; Gold; Human computer interaction; Natural language processing systems; Speech analysis; Speech recognition; Quality control

25Mg Solid-state NMR: A sensitive probe of adsorbing guest molecules on a metal center in metal-organic framework CPO-27-Mg - Xu, Jun; Terskikh, Victor V.; Huang, Yining (The Journal of Physical Chemistry Letters, 2012)
Metal-organic frameworks (MOFs) have excellent adsorption capability. To understand their adsorptive properties requires detailed information on the host-guest interaction. The information on MOF desolvation (or activation) is also crucial because the very first step of many applications requires removal of the solvent molecules occluded inside of the pores. Unfortunately, such information is not always available from powder XRD data. Solid-state NMR is an excellent complementary technique to XRD. CPO-27-Mg is a MOF with unusual adsorption ability. The adsorption involves a direct interaction between Mg and guest species. Herein, we present, for the first time, a natural abundance 25Mg solid-state NMR study of CPO-27-Mg at an ultrahigh magnetic field of 21.1 T. The results provide new physical insights into the effects of dehydration/rehydration and adsorption of guest species on the Mg local environment.
Keywords: Adsorption ability; Adsorption capability; Adsorptive properties; Desolvation; Direct interactions; Guest molecules; Guest species; Host guest interactions; Local environments; Metal centers; Metal organic framework; Natural abundance; Powder XRD; Sensitive probe; Solid state NMR; Solvent molecules; Ultra-high magnetic fields; XRD; Adsorption; Crystalline materials; Java programming language; Solid state physics; Nuclear magnetic resonance spectroscopy

The horizontal branch of NGC1851: constraints from its RR Lyrae variables - Kunder, Andrea; Salaris, Maurizio; Cassisi, Santi; De Propris, Roberto; Walker, Alistair; Stetson, Peter B.; Catelan, Márcio; Amigo, Pía (Astronomical Journal, 2012)
We use the pulsational properties of the RR Lyrae variables in the globular cluster NGC1851 to obtain detailed constraints of the various sub-stellar populations present along its horizontal branch. On the basis of detailed synthetic horizontal branch modeling, we find that minor helium variations (Y ∼ 0.248-0.280) are able to reproduce the observed periods and amplitudes of the RR Lyrae variables, as well as the frequency of fundamental and first-overtone RR Lyrae stars. Comparison of number ratios among the blue and red horizontal branch components and the two observed subgiant branches also suggest that the RR Lyrae variables originated from the progeny of the bright subgiant branch. The RR Lyrae variables with slightly enhanced helium (Y ∼ 0.270-0.280) have longer periods at a given amplitude, as is seen with Oosterhoff II (OoII) RR Lyrae variables, whereas the RRLyrae variables with Y ∼ 0.248-0.270 have shorter periods, exhibiting properties of Oosterhoff I (OoI) variables. This correlation does suggest that the pulsational properties of RR Lyrae stars can be very useful for tracing the various subpopulations and can provide suitable constraints on the multiple population phenomenon. It appears to be of great interest to explore whether this conclusion can be generalized to other globular clusters hosting multiple populations.

Entangling the motion of diamonds at room temperature - Sprague, Michael R.; Lee, K. C.; Sussman, Ben J.; Nunn, Josh; Langford, Nathan K.; Jin, Xian-Min; Champion, Tessa; Michelberger, Patrick; Reim, Klaus F.; England, Duncan G.; Jaksch, Dieter; Walmsley, Ian A. (2012 Conference on Lasers and Electro-Optics, CLEO 2012, 2012)
We demonstrate entanglement between the vibrational mode of two macroscopic, spatially-separated diamonds at room temperature with ultrashort pulses and a far-off-resonant Raman interaction. © 2012 OSA.
Keywords: Raman interactions; Room temperature; Vibrational modes; Lasers

BSA nanoparticles for siRNA delivery: Coating effects on nanoparticle properties, plasma protein adsorption, and in vitro siRNA delivery - Yogasundaram, H.; Bahniuk, M.S.; Singh, H.-D.; Aliabadi, H.M.; Uludaǧ, H.; Unsworth, L.D. (International Journal of Biomaterials, 2012)
Developing vehicles for the delivery of therapeutic molecules, like siRNA, is an area of active research. Nanoparticles composed of bovine serum albumin, stabilized via the adsorption of poly-L-lysine (PLL), have been shown to be potentially inert drug-delivery vehicles. With the primary goal of reducing nonspecific protein adsorption, the effect of using comb-type structures of poly(ethylene glycol) (1 kDa, PEG) units conjugated to PLL (4.2 and 24 kDa) on BSA-NP properties, apparent siRNA release rate, cell viability, and cell uptake were evaluated. PEGylated PLL coatings resulted in NPs with ζ-potentials close to neutral. Incubation with platelet-poor plasma showed the composition of the adsorbed proteome was similar for all systems. siRNA was effectively encapsulated and released in a sustained manner from all NPs. With 4.2 kDa PLL, cellular uptake was not affected by the presence of PEG, but PEG coating inhibited uptake with 24 kDa PLL NPs. Moreover, 24 kDa PLL systems were cytotoxic and this cytotoxicity was diminished upon PEG incorporation. The overall results identified a BSA-NP coating structure that provided effective siRNA encapsulation while reducing ζ-potential, protein adsorption, and cytotoxicity, necessary attributes for in vivo application of drug-delivery vehicles. Copyright © 2012 Haran Yogasundaram et al.

Powder processing and coating heat treatment on cold sprayed Ti-6Al-4V alloy - Wong, W.; Irissou, E.; Legoux, J.G.; Vo, P.; Yue, S. (Materials Science Forum, 2012)
This study investigates the effect of powder processing on powder flowability, compact ability, and the heat treatment of the resulting coatings on the mechanical properties of cold gas dynamic sprayed Ti-6Al-4V alloy. Nitrogen gas was used throughout the coating deposition process. Propellant gas temperature and pressure were attuned to maximize particle impact velocity. Three powder processing conditions were used in this study: as received (AR), low-energy ball milled (BM), and argon atmosphere heat treated (HT). Results showed coating porosities of around 6 to 7%, regardless of the feedstock powder used or the heat treatment performed. It was observed at 600 and 800°C anneals that a coating hardness reduction occurred, possibly due to static recovery and recrystallization, with minor sintering possibly occurring at the 800°C anneals. In addition, micro tensile tests showed an increase in cohesion strength at higher heat treatment temperatures. © 2012 Trans Tech Publications, Switzerland.
Keywords: Argon atmospheres; Ball-milled; Coating deposition; Coating hardness; Coating porosity; Cohesion strength; Cold spray; Feedstock powders; Heat treatment temperature; Low energies; Micro tensile tests; Nitrogen gas; Particle impact velocities; Powder flowability; Powder processing; Propellant gas; Static recovery; Ti-6al-4v; Ti-6Al-4V alloy; Aluminum; Argon; Cerium alloys; Heat treatment; Mechanical properties; Nitrogen; Powder coatings; Sintering; Sprayed coatings; Tensile strength; Tensile testing; Titanium alloys; Vanadium; Vanadium alloys; Aluminum coatings

How starless are starless cores? - Schnee, S.; Di Francesco, J.; Enoch, M.; Friesen, R.; Johnstone, D.; Sadavoy, S. (The Astrophysical Journal, 2012)
In this paper, we present the results of Combined Array for Research in Millimeter-wave Astronomy continuum and spectral line observations of the dense core Per-Bolo 45. Although this core has previously been classified as starless, we find evidence for an outflow and conclude that Per-Bolo 45 is actually an embedded, low-luminosity protostar. We discuss the impact of newly discovered, low-luminosity, embedded objects in the Perseus molecular cloud on starless core and protostar lifetimes. We estimate that the starless core lifetime has been overestimated by 4%-18% and the Class 0/I protostellar lifetime has been underestimated by 5%-20%. Given the relatively large systematic uncertainties involved in these calculations, variations on the order of 10% do not significantly change either core lifetimes or the expected protostellar luminosity function. Finally, we suggest that high-resolution (sub)millimeter surveys of known cores lacking near-infrared and mid-infrared emission are necessary to make an accurate census of starless cores. © 2012. The American Astronomical Society. All rights reserved.

Initial conditions for star formation in clusters: Physical and kinematical structure of the starless core Oph A-N6 - Bourke, T.L.; Myers, P.C.; Caselli, P.; Di Francesco, J.; Belloche, A.; Plume, R.; Wilner, D.J. (The Astrophysical Journal, 2012)
We present high spatial (<300AU) and spectral (0.07kms -1) resolution Submillimeter Array observations of the dense starless cluster core Oph A-N6 in the 1mm dust continuum and the 3-2 line of N 2H + and N 2D +. The dust continuum observations reveal a compact source not seen in single-dish observations, of size 1000AU and mass 0.005-0.01 M. The combined line and single-dish observations reveal a core of size 3000 × 1400AU elongated in a NW-SE direction, with almost no variation in either line width nor line center velocity across the map, and very small non-thermal motions. The deuterium fraction has a peak value of 0.15 and is >0.05 over much of the core. The N 2H + column density profile across the major axis of Oph A-N6 is well represented by an isothermal cylinder, with temperature 20K, peak density 7.1 × 10 6cm -3, and N 2H + abundance 2.7 × 10 -10. The mass of Oph A-N6 is estimated to be 0.29 M , compared to a value of 0.18 M from the isothermal cylinder analysis, and 0.63 M for the critical mass for fragmentation of an isothermal cylinder. Compared to isolated low-mass cores, Oph A-N6 shows similar narrow line widths and small velocity variation, with a deuterium fraction similar to "evolved" dense cores. It is significantly smaller than isolated cores, with larger peak column and volume density. The available evidence suggests that Oph A-N6 has formed through the fragmentation of the Oph A filament and is the precursor to a low-mass star. The dust continuum emission suggests that it may already have begun to form a star. © 2012. The American Astronomical Society. All rights reserved.

On Liquation and Liquid Phase Oxidation during Linear Friction Welding of Nickel-Base IN738 and CMSX Superalloys - Amegadzie, M.Y.; Ola, O.T.; Ojo, O.A.; Wanjara, P.; Chaturvedi, M.C. (Superalloys 2012, 2012)
A systematic study of the microstructural response of conventionally cast IN 738 and single crystal CMSX 486 superalloys during linear friction welding was performed. The results revealed that, aside from a significant liquation of various phases that occurred during joining, continuous oxide films formed on the weld lines in both materials. The weld line oxides consisted of aluminum-rich and hafnium-base oxides in IN 738 and CMSX 486 superalloys, respectively, which can be deleterious to the mechanical properties of the weld joint. Gleeble thermo-mechanical simulation showed that the oxides were produced by the oxidation of some liquid exposed to atmospheric oxygen at the mating surfaces of the work pieces. A practicable method of eliminating liquid phase oxidation during linear friction welding of nickel-base superalloys is discussed. © 2012 The Minerals, Metals, & Materials Society. All rights reserved.

POEs for green buildings - Birt, B.J.; Newsham, G.R.; Veitch, J.A.; Arsenault, C. (Lighting Design and Application: LD and A, 2012)

Neutron diffraction analysis of phase precipitation in solidification of hypereutectic Al-Si alloys with the addition of Cu and Mg - Sediako, D.; Kasprzak, W. (TMS Light Metals, 2012)
A good understanding of the kinetics of evolution of solid phases during solidification of hypereutectic aluminum alloys is a key factor in controlling the as-cast microstructure and, in turn, enhancing the service properties of industrial alloys. A study was performed to evaluate the solidification kinetics for two hypereutectic Al-19%Si alloys with the addition of 3%Cu and 3%Cu+1%Mg. This study included thermodynamic calculations of the solidification process using the FactSage™ 6.2 software package, as well as experimental thermal analysis, and neutron diffraction. The study revealed kinetics of solid Al, solid Si, Al 2CU, and Mg 2Si evolution, as well as an individual effect of Cu and Mg alloying additions on the solidification path of the Al-Si system.
Keywords: Alloying additions; As cast microstructure; FactSage; Hypereutectic Al-Si alloys; Hypereutectic aluminum-silicon alloys; Industrial alloys; Key factors; Neutron diffraction analysis; Phase precipitations; Service properties; Si alloys; Solid phasis; Solid-phase; Solidification kinetics; Solidification process; Thermodynamic calculations; Aluminum; Aluminum alloys; Binary alloys; Exhibitions; Kinetics; Neutron diffraction; Precipitation (chemical); Silicon; Silicon alloys; Thermoanalysis; Solidification

Microstructures, mechanical properties, and erosion resistance of unbalanced magnetron sputtering deposited TiN/VN nano-structured coatings - Yang, Q.; Bielawski, M.; McKellar, R.C. (Metallography, Microstructure, and Analysis, 2012)
Nano-structured TiN/VN coatings with a range of bi-layer periods from 3. 4 to 11. 0 nm were deposited on ferromagnetic 410 stainless steel (410SS) and non-ferromagnetic Ti-6Al-4V titanium alloy substrates using an Unbalanced Magnetron Sputtering (UMS) technique; the microstructure, mechanical properties, and erosion performance of the as-sputtered coating were evaluated. While the surface morphologies of the coatings on these two substrates were different, the XRD measurements complemented by a texture evaluation through pole figures indicated that the preferred orientations of the TiN/VN coatings on 410SS and Ti-6Al-4V were also dissimilar. A nano-mechanical indentation technique was used to determine hardness and Young's modulus, and it was found that these parameters varied with superlattice bi-layer period and were dependent on the type of substrate material. Furthermore, the erosion resistances of the TiN/VN coatings were markedly higher than the bare substrate counterparts, and were influenced by the substrate type. Specifically, the differences in the microstructures and properties of the coatings were attributed to the difference in ion flux during the UMS deposition due to the dissimilar magnetic properties of the substrate materials. © 2012 Springer Science+Business Media, LLC and ASM International.
Keywords: Aerospace; Bi-layer; Erosion resistance; Ion fluxes; Microstructures and properties; Nano-structured; Nanostructured coatings; Non-ferromagnetic; Pole figure; Preferred orientations; Substrate material; Substrate types; Surface engineering; Ti-6al-4v; Ti-6al-4v titanium alloys; Unbalanced magnetron sputtering; XRD measurements; Young's Modulus; Aluminum coatings; Coatings; Deposits; Dissimilar materials; Elastic moduli; Erosion; Ferromagnetic materials; Ferromagnetism; Indentation; Magnetic properties; Microstructure; Titanium alloys; Tribology; Substrates

Cell surface glycoproteins from Thermoplasma acidophilum are modified with an N-linked glycan containing 6-C-sulfofucose - Vinogradov, E.; Deschatelets, L.; Lamoureux, M.; Patel, G.B.; Tremblay, T.-L.; Robotham, A.; Goneau, M.-F.; Cummings-Lorbetskie, C.; Watson, D.C.; Brisson, J.-R.; Kelly, J.F.; Gilbert, M. (Glycobiology, 2012)
Thermoplasma acidophilum is a thermoacidophilic archaeon that grows optimally at pH 2 and 59°C. This extremophile is remarkable by the absence of a cell wall or an S-layer. Treating the cells with Triton X-100 at pH 3 allowed the extraction of all of the cell surface glycoproteins while keeping cells intact. The extracted glycoproteins were partially purified by cation-exchange chromatography, and we identified five glycoproteins by N-terminal sequencing and mass spectrometry of in-gel tryptic digests. These glycoproteins are positive for periodic acid-Schiff staining, have a high content of Asn including a large number in the Asn-X-Ser/Thr sequon and have apparent masses that are 34-48 larger than the masses deduced from their amino acid sequences. The pooled glycoproteins were digested with proteinase K and the purified glycopeptides were analyzed by NMR. Structural determination showed that the carbohydrate part was represented by two structures in nearly equal amounts, differing by the presence of one terminal mannose residue. The larger glycan chain consists of eight residues: six hexoses, one heptose and one sugar with an unusual residue mass of 226 Da which was identified as 6-deoxy-6-C-sulfo-d-galactose (6-C-sulfo-d-fucose). Mass spectrometry analyses of the peptides obtained by trypsin and chymotrypsin digestion confirmed the principal structures to be those determined by NMR and identified 14 glycopeptides derived from the main glycoprotein, Ta0280, all containing the Asn-X-Ser/Thr sequons. Thermoplasma acidophilum appears to have a "general" protein N-glycosylation system that targets a number of cell surface proteins. © 2012 The Author.
Keywords: Thermoplasma; glycoprotein; N-linked glycan; sulfofucose

Selecting the polarization in silicon photonic wire components - Xu, Dan-Xia; Delâge, André; Schmid, Jens H.; Ma, Rubin; Wang, Shurui; Lapointe, Jean; Vachon, Martin; Cheben, Pavel; Janz, Siegfried (SPIE - International Society for Optical Engineering. Proceedings, 2012)
Silicon photonic wire waveguides are usually highly birefringent, so they are generally designed to operate for one particular polarization. For commonly used waveguides with a silicon thickness of 220 nm, TE polarization is preferred since TM is only weakly guided. For waveguides with a silicon thickness larger than 250 nm, both TE and TM polarizations have been employed. Overall, the choice of polarization has largely appeared arbitrary. In this presentation we review the pertinent polarization-dependent waveguide properties, including losses, back-reflection, polarization conversion and fabrication tolerances, with the intent to suggest guidelines for choosing the proper polarization. Through experimental evidence, we show that TM polarization has several important advantages and can support high performance resonators with a radius down to 2 μm. © 2012 SPIE.
Keywords: Polarization conversion; Polarization diversity; Polarization independence; Ring resonator; Silicon photonics; Birefringence; Directional couplers; Optical waveguides; Photonic devices; Waveguides; Polarization

A comparison of the mechanical design of fiber feeds for GRACES and GHOS - Anthony, A.; Hill, A.; Pazder, J.; Szeto, K.; Halman, M.; Tollestrup, E.; Barrick, G. (SPIE - International Society for Optical Engineering. Proceedings, 2012)
The instrument group of the Herzberg Institute of Astrophysics has been commissioned by the Gemini Observatory to participate in a competitive conceptual design study for a new Gemini High-Resolution Optical Spectrograph (GHOS). Concurrently this same group is working in partnership with both the Gemini and CFH Telescopes to design the Gemini Remote Access to CFHT ESPaDOnS Spectrograph, (GRACES). Both these instruments will use a fiber feed allowing light received by the Gemini telescope to be processed via remotely positioned instruments. This paper will explore the similarities and differences in requirements, inherent challenges, concepts, design solutions and areas of concept sharing. © 2012 SPIE.
Keywords: Design solutions; Focal ratio degradation; Gemini telescopes; High resolution; Mechanical design; Optical spectrograph; Remote access; Astrophysics; Conceptual design; Optical telescopes; Optics; Spectrographs; Telescopes; Fibers

Self-induced thermal nonlinearities in InGaAsP microtubes at telecom wavelengths - Tian, Z.; Bianucci, P.; Dastjerdi, M.H.T.; Mi, Z.; Poole, P.J.; Plant, D.V. (2012 Conference on Lasers and Electro-Optics, CLEO 2012, 2012)
We demonstrate, for the first time, dynamical thermal effects in InGaAsP microtubes at telecom wavelengths. Such effect can be avoided or exploited for passive or active applications by choosing appropriate resonance wavelengths. © 2012 OSA.
Keywords: Active application; InGaAsP; Micro-tubes; Resonance wavelengths; Telecom wavelengths; Thermal nonlinearities; Lasers

Probing the experimental phonon dispersion of graphene using 12C and 13C isotopes - Bernard, S.; Whiteway, E.; Yu, V.; Austing, D.G.; Hilke, M. (Physical Review B - Condensed Matter and Materials Physics, 2012)
Using very uniform large-scale chemical vapor deposition grown graphene transferred onto silicon, we were able to identify 15 distinct Raman lines associated with graphene monolayers. This was possible thanks to a combination of different carbon isotopes and different Raman laser energies and extensive averaging without increasing the laser power. This allowed us to obtain a detailed experimental phonon dispersion relation for many points in the Brillouin zone. We further identified a D+D′ peak corresponding to a double-phonon process involving both an inter- and intravalley phonon. © 2012 American Physical Society.

Band engineering in nanowires: Ab initio model of band edges modified by (111) biaxial strain in group IIIA-VA semiconductors - Kadantsev, E.S.; Zieliński, M.; Hawrylak, P. (Physical Review B - Condensed Matter and Materials Physics, 2012)
Quantum dots in nanowires grow on a (111) substrate and it is expected that the modifications of the band structure due to a biaxial strain in the (111) crystallographic plane will determine the confinement of charge carriers in these systems. In this work, we develop an ab initio methodology for the determination of biaxial strain-modified band energies on an absolute energy scale due to a strain in an arbitrary crystallographic plane and apply it to calculate the evolution of band edges in group IIIA-VA zinc-blende semiconductors (InP, InAs, and GaAs) under the (111) biaxial strain. The absolute hydrostatic deformation potentials, a prerequisite for the accurate calculation of the strain-modified band energies within our scheme, are determined. The strain tensor for an InAs dot grown on a (111) GaAs substrate is calculated and the importance of the (111) biaxial strain is demonstrated. The strained band offsets in InAs under a compressive biaxial strain in the (001) and (111) crystallographic planes as well as the local band structure in a InAs/GaAs dot indicates a stronger confinement of holes in the (111) case. ©2012 American Physical Society.

Stable expression of chimeric heavy chain antibodies in CHO cells - Agrawal, V.; Slivac, I.; Perret, S.; Bisson, L.; St-Laurent, G.; Murad, Y.; Zhang, J.; Durocher, Y. (Methods in Molecular Biology, 2012)
Camelid single domain antibodies fused to noncamelid Fc regions, also called chimeric heavy chain antibodies (cHCAb), offer great potential as therapeutic and diagnostic candidates due to their relatively small size (80 kDa) and intact Fc. In this chapter, we describe two approaches, limiting dilution and minipools, for generating nonamplified Chinese hamster ovary cell lines stably expressing cHCAb in suspension and serum-free cultures using a stringent antibiotic selection. Neither of the protocols necessitates the acquisition or implementation of expensive automated infrastructures and thus could be applied in any lab with minimal cell culture setup. The given protocol allows the isolation of stable clones capable of generating up to 100 mg/L of antibody in batch mode performed in shaker flasks. © 2012 Springer Science+Business Media, LLC.
Keywords: antibiotic g 418; blasticidin S; chimeric antibody; chimeric heavy chain antibody; hygromycin B; phleomycin; plasmid vector; polyethyleneimine; puromycin; unclassified drug; hybrid protein; immunoglobulin heavy chain; monoclonal antibody; animal cell; antibody production; article; CHO cell; cloning; controlled study; culture technique; drug activity; genetic transfection; heavy chain; nonhuman; priority journal; protein expression; suspension cell culture; toxicity; animal; gene expression; gene order; gene vector; genetics; hamster; isolation and purification; metabolism; Animals; Antibodies, Monoclonal; CHO Cells; Cricetinae; Gene Expression; Gene Order; Genetic Vectors; Immunoglobulin Heavy Chains; Recombinant Fusion Proteins; Transfection

Sr+88 445-THz single-ion reference at the 10 -17 level via control and cancellation of systematic uncertainties and its measurement against the SI second - Madej, Alan A.; Dubé, Pierre; Zhou, Zichao; Bernard, John E.; Gertsvolf, Marina (Physical Review Letters, 2012)
We describe experiments and measurements on a trapped and laser-cooled single ion of Sr+88 which, when probed on its reference 5sS1/22→4dD5/22 transition at 445THz, provides an optical frequency standard of evaluated accuracy outperforming the current realization of the SI second. Studies are presented showing that micromotion-associated shifts of the standard can be reduced to the 10 -18 level and uncertainties in the blackbody-induced shifts for the current system are at the low 10 -17 level due to the relatively well-known polarizability of the strontium ion system and careful choice of the trap structure. The current evaluated systematic shifts for the ion transition are at a fractional uncertainty of 2×10 -17. An absolute frequency measurement performed over a two-month period relative to a maser referenced to the SI second via Global Positioning System time transfer has determined the center frequency for the transition at ν SD= 444779044095485.5±0.9Hz (1σ).
Keywords: Absolute frequency measurements; Center frequency; Ion transition; Laser-cooled; Optical frequency standard; Polarizabilities; Single ion; Strontium ion; Systematic uncertainties; Time transfer; Frequency standards; Ions; Strontium; Uncertainty analysis

High speed routing of woven carbon fiber reinforced epoxy laminates - Meshreki, M.; Sadek, A.; Attia, M.H. (ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 2012)
Little is known about the high speed routing of Carbon Fiber Reinforced Polymers (CFRP). Most of the work in the literature has focused on the drilling of CFRP. In this paper, an extensive experimental study has been conducted to better understand the dynamic, tribological, and thermal characteristics of high speed milling of CFRPs, in the range of 10,000 to 40,000 rpm (200 to 800 m/min, for 6.35 mm end-mill). The material used was a quasi-isotropic laminate comprising 35 plies of woven graphite epoxy. The tool wear was investigated on the flank and the rake faces. The machined slots were characterized in terms of straightness errors, dimensional errors, surface roughness, and delamination. The tool over-hang controls the tool dynamics, in this high speed range, and significantly affect various quality attributes of the produced holes; roughness, dimensional errors, and straightness. Similar trends were observed for the forces and the temperatures, whereby there is a given speed at which they reach a minimum and then they start to increase for higher speeds. The machining force and temperature trends with varying speeds and feeds are controlled by the chip load, the specific cutting pressures, and the effect of the frictional forces. The increased tool wear was found to directly affect the cutting forces and consequently lead to high delamination and surface roughness. The milled surface quality was mainly controlled by the feed rate. Limited surface delamination was observed due to the low axial forces associated with the routing process. Copyright © 2012 by ASME.
Keywords: Carbon fiber reinforced; Carbon fiber reinforced polymer; Quality attributes; Quasiisotropic laminates; Specific cutting pressure; Straightness errors; Temperature trends; Thermal characteristics; Carbon fiber reinforced plastics; Delamination; Errors; Laminates; Mechanical engineering; Milling (machining); Quality control; Surface roughness; Tools; Wear of materials; Weaving; Speed

Perforated metal sheets as gas diffusion layers for proton exchange membrane fuel cells - Blanco, M.; Wilkinson, D.P.; Wang, H. (Electrochemical and Solid-State Letters, 2012)
The use of perforated metal sheets as engineered gas diffusion layers (GDL) in proton exchange membrane (PEM) fuel cells was investigated. The effect of different thicknesses, perforation diameter, and in-plane diffusion capabilities were analyzed along with freestanding microporous layers in order to improve gas and water transport. Although these structured GDLs are in an early stage of development, they provide baseline performance at lower current densities, and may already have potential for some specific applications. In addition, the design, manufacturing, and modeling processes with predictive capability can be improved due to their simplified nature. © 2011 The Electrochemical Society.
Keywords: Base-line performance; Gas diffusion layers; In-plane diffusion; Metal sheets; Microporous layers; Modeling process; Predictive capabilities; Water transport; Proton exchange membrane fuel cells (PEMFC); Protons; Sheet metal; Diffusion in gases

Induced currents in the quantum Hall regime: Energy storage, persistence, and I-V characteristics - Smith, M.J.; Usher, A.; Williams, C.D.H.; Shytov, A.; Sachrajda, A.S.; Kam, A.; Wasilewski, Z.R. (Physical Review B - Condensed Matter and Materials Physics, 2012)
Induced currents associated with the quantum Hall effect are studied in the temperature range 39mK to 1.6K, and at Landau-level filling factors ν=1,2,3,4, and 6, using torsion-balance magnetometry. A quantitative link is demonstrated between (nonlinear induced current) vs (inducing electromotive force) curves, and the subexponential decay of the induced current in a static magnetic field. The energy storage in the induced currents is reexamined with the conclusion that the predominant mechanism for storage is inductive, through the mutual inductance between the sample and the magnet, not capacitive as previous reports have assumed. The temperature dependencies of the currents are consistent with previous models, except for a low-temperature saturation at filling factors ν=1 and ν=2, which we attribute to electron heating. © 2012 American Physical Society.

Mechanical property-porosity relationships of layered calcium silicate hydrate phases - Pourbeik, P.; Beaudoin, J.J.; Alizadeh, R.; Raki, L. (Materials and Structures/Materiaux et Constructions, 2012)
Dynamic mechanical analysis measurements were made on the following calcium-silicate- hydrate systems: 1.4 nm tobermorite (T), jennite (J), synthetic C-S-H (C/S = 0.80, 1.20 and 1.50) and cement paste. The age of the cement paste varied from 3 days to 45 years. Plots of storage modulus versus porosity were constructed for all these materials. The non-uniqueness of the curves is discussed with reference to Taylor's analysis of strength-porosity curves and the influence of particle type, density and crystallinity. Additional insights regarding the practical application of T-J and T-CH nanostructural models for the C-S-H nanostructure in hydrated cements is provided. © 2012 RILEM.

Evaluation of sealed joint performance for the selection of sealants suitable for use in autoclaved lightweight concrete panels - Miyauchi, H.; Lacasse, M. A.; Murata, S.; Enomoto, N.; Tanak, K. (ASTM Special Technical Publication, 2012)
The strength of autoclaved lightweight concrete (ALC) is evidently lower than that of normal concrete. Therefore, when movement occurs at a sealed joint between ALC panels, the sealant is required to deform and remain intact without damaging the ALC substrate. However, there is currently not sufficient information to permit evaluation of the expected performance of sealants applied to ALC substrates. In this study, static and dynamic tests were carried out in order to obtain an index that could be used to select the modulus of a sealant that can be expected to provide long-term performance when applied to an ALC substrate. To develop this index, an initial study was carried out in order to clarify actual joint movement between ALC panels of buildings; the expansion and contraction at the joint were measured, and shear joint movement was calculated based on the expected story-to-story drift of an external wall due to earthquake loads. Thereafter, in a subsequent stage of the study, five types of two-component polyurethane sealant products, of different elastic modulus, were subjected to tensile and shear tests from which the relationship between stress and the type of joint fracture was determined. The results from these tests revealed that when the stress is greater than 0.6 to 0.7 N/mm2, the ALC substrate is more easily fractured than the sealant. In a final stage of the study, the cyclic fatigue resistance of the same two-component sealants was evaluated using tensile and shear fatigue tests. Results from the fatigue tests indicated that the high modulus sealants lost adhesion from the ALC substrate at an early stage in the test. As well, the fatigue resistance of test specimens with joints having three-sided adhesion was lower than that of specimens having normally configured joints with adhesion on two sides of the sealant. Therefore, on the basis of results derived from all the studies, it was determined that a suitable sealant for use on ALC substrates is a sealant having a low modulus that is applied in the normal fashion as a two-sided joint. Copyright © 2012 by ASTM International.
Keywords: Earthquake load; Expansion and contraction; External walls; Joint fracture; Joint movement; Joint performance; Lightweight concrete panel; Long term performance; Low modulus; Modulus; Normal concretes; Sealant products; Shear joints; Shear tests; Static and dynamic; Test specimens; Two-component; Wall panels; Adhesion; Adhesives; Concrete slabs; Construction; Durability; Fatigue of materials; Fatigue testing; Fracture; Precast concrete; Substrates; Walls (structural partitions); Sealants

Feasibility of infrared spectroscopy with pattern recognition techniques to identify a subpopulation of mares at risk of producing foals diagnosed with failure of transfer of passive immunity - Riley, C.; Mcclure, J.; Low-Ying, S.; Dolenko, B.; Somorjai, R.; Shaw, R. (Australian Veterinary Journal, 2012)
Objective: To assess the feasibility of a serum-based test using infrared spectroscopy to identify a subpopulation of mares at risk of producing foals susceptible to failure of passive transfer of immunity (FPT) because of mare-associated factors. Materials and methods: Serum was collected from post-parturient mares (n = 126) and their foals at 24-72h of age. A radial immunodiffusion IgG test was used to determine each foal's serum IgG concentration. Infrared absorbance spectra of dam sera were collected in the wave number range of 400-4000cm-1. Following data preprocessing, pattern recognition techniques were used to identify spectroscopic information capable of distinguishing between mares with FPT foals and those with normal foals. The sensitivity and specificity of infrared spectroscopy to detect risk-positive mares were calculated. Results: Five wave number regions were identified as optimal for distinguishing between the two groups of mares: 740.9-785.2cm-1, 796.8-816.0cm-1, 970.4-993.5cm-1, 1371.6-1406.3cm-1 and 1632.0-1659.0cm-1. Based upon the infrared spectroscopic information within these discriminatory subregions, the spectra provided the risk status of the mares with a classification success rate of 81.0%. The sensitivity of the classification system was 85.7% and specificity was 80.0%. Conclusion: This preliminary study demonstrates that infrared spectra of dam serum have the potential to provide the basis for a new periparturient screening method for a subpopulation of mares at risk of having a foal susceptible to FPT. Further development may provide an economic and rapid technique for the pre-parturient assessment of mares. © 2012 The Authors. Australian Veterinary Journal © 2012 Australian Veterinary Association.
Keywords: immunoglobulin G; animal; animal disease; article; blood; feasibility study; female; horse; horse disease; immunology; infrared spectroscopy; methodology; newborn; passive immunization; physiology; puerperium; sensitivity and specificity; Animals; Animals, Newborn; Feasibility Studies; Female; Horse Diseases; Horses; Immunity, Maternally-Acquired; Immunization, Passive; Immunoglobulin G; Postpartum Period; Sensitivity and Specificity; Spectroscopy, Fourier Transform Infrared

CliFin: A web-based geographical information system for time dependant point of care localization in New Brunswick, Canada - Tulpan, D.; Mancuso, M.; Durand, G.; Regoui, C.; Belliveau, L. (International Journal of Healthcare Information Systems and Informatics, 2012)
Over the past decade, the development of web-based Geographic Information Systems (GIS) for health has grown quite rapidly due to an increased need of data integration and spatial visualization. One GIS growth area in health is the construction of map-based applications that provide information on health care resources. Such applications are typically used as standard tools by public health departments, public health policy and research organizations, hospitals and health insurance organizations to provide public access to health care resources. This paper presents the design and development process of Clinic Finder (CliFin) - an open-access web-based GIS application relying on the Google Maps technology and providing access to a database with point of care facilities across the Province of New Brunswick, Canada. The uniqueness of CliFin consists in the implementation of a time-frame dependent search and results trimming approach, which allows users to identify clinics and hospitals open at any given time. The users are also encouraged to contribute with schedule updates and new point of care information to further develop CliFin's database and its accuracy. The combination of GIS visualization capabilities, database management, user involvement in database update and the time-frame dependence of search results, confers CliFin increased practicality, especially in situations of crisis such as natural disasters. Copyright © 2012, IGI Global.
Keywords: Canada; Clinic Finder (CliFin); New Brunswick; Point of care; Web servers; Database systems; Health; Health care; Health insurance; Hospitals; Public health; Visualization; Websites; Geographic information systems

Rolled-up 1.55 μm semiconductor quantum dot tube lasers - Mi, Z.; Bianucci, P.; Tavakoli-Dastjerdi, M.H.; Mukherjee, S.; Djavid, M.; Poole, P.J. (ECS Transactions, 2012)
We report on the fabrication and characterization of InGaAsP/InAs quantum dot rolled-up tubes as well as the achievement of a semiconductor tube laser at ∼ 1.55 μn. The optically pumped tube laser operates in continuous wave at liquid nitrogen temperature and shows an ultra-low threshold of ∼1.26 μW. ©The Electrochemical Society.
Keywords: Continuous Wave; InGaAsP; Liquid nitrogen temperature; Optically pumped; Ultra-low threshold; Nanotechnology; Pumping (laser); Semiconductor lasers; Semiconductor quantum dots; Tubes (components); Optically pumped lasers

Mid-IR broadband quantum cascade laser frequency-comb - Hugi, A.; Blaser, S.; Liu, H.C.; Faist, J. (2012 Conference on Lasers and Electro-Optics, CLEO 2012, 2012)
We show a free-running broadband QCL emitting a frequency-comb of 490 nm at 7μm whose spectral phase signature resembles to the one of a frequency-modulate laser. Beatnote-linewidths as narrow as f < 10Hz are measured. © 2012 OSA.
Keywords: Phase signature; Quantum cascade lasers; Lasers

The JCMT Nearby Galaxies Legacy Survey - VIII. CO data and the L CO(3-2)-L FIR correlation in the SINGS sample - Wilson, C.D.; Warren, B.E.; Israel, F.P.; Serjeant, S.; Attewell, D.; Bendo, G.J.; Butner, H.M.; Chanial, P.; Clements, D.L.; Golding, J.; Heesen, V.; Irwin, J.; et al. (Monthly Notices of the Royal Astronomical Society, 2012)
The James Clerk Maxwell Telescope Nearby Galaxies Legacy Survey (NGLS) comprises an Hi-selected sample of 155 galaxies spanning all morphological types with distances less than 25Mpc. We describe the scientific goals of the survey, the sample selection and the observing strategy. We also present an atlas and analysis of the CO J=3 - 2 maps for the 47 galaxies in the NGLS which are also part of the Spitzer Infrared Nearby Galaxies Survey. We find a wide range of molecular gas mass fractions in the galaxies in this sample and explore the correlation of the far-infrared luminosity, which traces star formation, with the CO luminosity, which traces the molecular gas mass. By comparing the NGLS data with merging galaxies at low and high redshift, which have also been observed in the CO J=3 - 2 line, we show that the correlation of far-infrared and CO luminosity shows a significant trend with luminosity. This trend is consistent with a molecular gas depletion time which is more than an order of magnitude faster in the merger galaxies than in nearby normal galaxies. We also find a strong correlation of the L FIR/L CO(3-2) ratio with the atomic-to-molecular gas mass ratio. This correlation suggests that some of the far-infrared emission originates from dust associated with atomic gas and that its contribution is particularly important in galaxies where most of the gas is in the atomic phase. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.

Microbial characteristics and influence factors during anaerobic fermentation for biohydrogen production from CO - Zhao, Y.; Liu, Z.; Liu, F.; Guiot, S.R. (Chinese Journal of Applied and Environmental Biology, 2012)
The biohydrogen production from anaerobic fermentation was studied with thermophilic bacterium Carboxydothermus hydrogenoformans using carbon monoxide (CO) dissolved in fermentation broth as the substrate. Bacterium growth model, decay efficient and the maximum specific growth rate were observed based on the experimental study of biomass growing, flocculation and microbial characteristics. The results indicated the feasibility of continuous anaerobic fermentation for hydrogen production from CO with C. hydrogenoformans due to its good hydrogen yield and flocculation ability. Furthermore, by investigating the effect of procedure parameters during CO fermentation, the optimal feed/microorganism was proposed and the maximum CO concentration was observed to avoid CO inhibition which was the key factor to consider in the study of continuous biohydrogen production from CO fermentation.
Keywords: Bacteria (microorganisms); Carboxydothermus hydrogenoformans

Review of tools for friction stir welding and processing - Zhang, Y.N.; Cao, X.; Larose, S.; Wanjara, P. (Canadian Metallurgical Quarterly, 2012)
Friction stir welding (FSW) is a novel green manufacturing technique due to its energy efficiency and environmental friendliness. This solid state joining process involves a rotating tool consisting of a shoulder and/or a probe. The shoulder applies a downward pressure to the workpiece surface, constrains the plasticised material around the probe, generates heat through the friction and causes plastic deformation in a relatively thin layer under the bottom surface of the shoulder. The rotating probe mainly drags along, plasticises, and mixes the adjacent material in the stir zone, creating a joint without fusion. Friction stir processing (FSP), a variant of FSW, has been developed to manufacture composites, locally eliminate casting defects, refine microstructure and/or improve the associated mechanical and physical properties including strength, ductility, fatigue, creep, formability and corrosion resistance. However, major challenges such as tool design and wear currently limit the use of FSW/P for manufacturing applications, particularly for high melting temperature or high strength alloys. In this review, the FSW/P tools are briefly summarised in terms of the tool types, shapes, dimensions, materials and wear behaviours. © 2012 Crown in Right of Canada.
Keywords: Bottom surfaces; Casting defect; Downward pressure; Environmental friendliness; Friction stir processing; Green manufacturing technique; Manufacturing applications; Mechanical and physical properties; Solid-state joining; Stir zones; Thin layers; Tool designs; Work pieces; Corrosion resistance; Energy efficiency; Friction stir welding; Gas welding; Joining; Mechanical properties; Probes; Shoulders (road); Tools; Processing

CAM-based planning, programming and execution of large-scale machining operations by a robot-mounted gantry system - Lambert, J.M.; de Montigny, M.; Perron, C. (SAE International Journal of Materials and Manufacturing, 2012)
This paper examines issues related to planning, programming and execution of machining operations by a robot in the context of machining large parts with complex geometries by a gantry-mounted robotic system. Parts were created from surface data in a CAD/CAM environment. The same environment was used to generate tool paths using a conventional machine tool approach. These paths were converted to robot trajectories and validated using mathematical kinematic models of the robotic system. Validation was performed according to various criteria related to process performance. Associated robot programs were then automatically generated. The manufacturing cell was progressively integrated according to requirements resulting from iterative process characterization. A metrology-based calibration procedure was designed that considerably improved the system's positioning precision. A custom user interface for online process monitoring was created as well as online cell program management capabilities to accommodate the large quantity of trajectory information. The system went from conceptual, to prototype-level to full production mode, thereby covering several Manufacturing Readiness Levels (MRL). The various strategies used in planning the process and programming the system demonstrate the viability of CAM-based approach for robot machining path generation without resorting to the use of OLP packages for validation of program generation. This could create a shift in the dependency on robotic specialists, allowing machine tool experts to carry about the programming of robot machining cells using the conventional machine tool approach.
Keywords: Automatically generated; Cad/cams; Calibration procedure; Complex geometries; Conventional machines; Gantry system; Iterative process; Kinematic model; Machining operations; On-line process monitoring; Path generation; Positioning precision; Process performance; Production modes; Program generation; Program management; Robot machining; Robot programs; Robot trajectory; Robotic systems; Surface data; Toolpaths; Trajectory information; Cams; Machining centers; Process monitoring; Robotics; Robots; User interfaces; Robot programming

Structures of merkel cell polyomavirus VP1 complexes define a sialic acid binding site required for infection - Neu, U.; Hengel, H.; Blaum, B.S.; Schowalter, R.M.; Macejak, D.; Gilbert, M.; Wakarchuk, W.W.; Imamura, A.; Ando, H.; Kiso, M.; Arnberg, N.; Garcea, R.L.; et al. (PLoS Pathogens, 2012)
The recently discovered human Merkel cell polyomavirus (MCPyV or MCV) causes the aggressive Merkel cell carcinoma (MCC) in the skin of immunocompromised individuals. Conflicting reports suggest that cellular glycans containing sialic acid (Neu5Ac) may play a role in MCPyV infectious entry. To address this question, we solved X-ray structures of the MCPyV major capsid protein VP1 both alone and in complex with several sialylated oligosaccharides. A shallow binding site on the apical surface of the VP1 capsomer recognizes the disaccharide Neu5Ac-α2,3-Gal through a complex network of interactions. MCPyV engages Neu5Ac in an orientation and with contacts that differ markedly from those observed in other polyomavirus complexes with sialylated receptors. Mutations in the Neu5Ac binding site abolish MCPyV infection, highlighting the relevance of the Neu5Ac interaction for MCPyV entry. Our study thus provides a powerful platform for the development of MCPyV-specific vaccines and antivirals. Interestingly, engagement of sialic acid does not interfere with initial attachment of MCPyV to cells, consistent with a previous proposal that attachment is mediated by a class of non-sialylated carbohydrates called glycosaminoglycans. Our results therefore suggest a model in which sialylated glycans serve as secondary, post-attachment co-receptors during MCPyV infectious entry. Since cell-surface glycans typically serve as primary attachment receptors for many viruses, we identify here a new role for glycans in mediating, and perhaps even modulating, post-attachment entry processes.
Keywords: glycosaminoglycan; protein VP1; sialic acid; capsid protein; glycosaminoglycan; n acetylneuraminic acid; oligosaccharide; virus DNA; virus receptor; VP1 protein, polyomavirus; article; binding site; cell adhesion; complex formation; crystallization; epitope mapping; ligand binding; merkel cell polyomavirus; mutagenesis; nonhuman; nucleotide sequence; protein expression; protein purification; protein structure; virus attachment; virus entry; virus morphology; virus mutation; cell line; chemical structure; chemistry; genetics; human; metabolism; mutation; physiology; polyomavirus infection; protein conformation; virology; X ray crystallography; Miridae; Polyomavirus; Binding Sites; Capsid Proteins; Cell Line; Crystallography, X-Ray; DNA, Viral; Epitope Mapping; Glycosaminoglycans; Humans; Merkel cell polyomavirus; Models, Molecular; Mutation; N-Acetylneuraminic Acid; Oligosaccharides; Polyomavirus Infections; Protein Conformation; Receptors, Virus; Virus Attachment; Virus Internalization

Effect of dietary protein level and source on digestive proteolytic enzyme activity in juvenile Senegalese sole, Solea senegalensis Kaup 1850 - Rodiles, A.; Santigosa, E.; Herrera, M.; Hachero-Cruzado, I.; Cordero, M.L.; Martínez-Llorens, S.; Lall, S.P.; Alarcón, F.J. (Aquaculture International, 2012)
The effect of dietary protein level and protein source on growth and proteolytic activity of juvenile Solea senegalensis was studied. In Experiment 1, fish were fed on four experimental diets containing increased protein levels (36, 46, 56 and 67%). In Experiment 2, Senegalese soles were fed on five diets with partial substitution of fish meal by soybean meal, soybean protein concentrate, soybean protein isolate, wheat gluten meal or pea protein concentrate. Results prove that growth and proteolytic activity in the distal intestine of fish were affected by the quantitative increase in dietary protein. The origin of protein source used in the elaboration of experimental diets affected both the amount and composition of the alkaline proteases secreted into the intestinal lumen; however, it did not decrease animal growth. Juvenile Senegalese sole showed capability to modulate digestive protease secretion when the concentration and/or source of dietary protein were modified. Quantity and quality of dietary protein affected protein hydrolysis in Senegalese sole intestine. This study establishes that 30% fish meal protein can be replaced by soybean derivatives without affecting intestinal proteases. Replacement with wheat gluten meal or pea protein concentrate should be taken cautiously, but further research is needed to establish whether growth performance and digestive enzyme physiology of Senegalese sole are affected by plant protein-supplemented diets in a long-term trial. © 2012 Springer Science+Business Media B.V.
Keywords: diet; enzyme activity; flatfish; food supplementation; growth response; hydrolysis; inhibitor; juvenile; physiology; protein; soybean; Animalia; Glycine max; Pisum sativum; Solea senegalensis; Soleidae; Triticum aestivum

Induction of tolerogenic dendritic cells by IL-6-secreting CT26 colon carcinoma - Alshamsan, A. (Immunopharmacology and Immunotoxicology, 2012)
One scenario by which tumors escape immune recognition is the constitutive activation of signal transducer and activator of transcription 3 (STAT3). This transcription factor mediates the production of tumor-derived factors that negatively influence target immune cells, such as dendritic cells, and polarize them toward immune-tolerance also through the induction of STAT3 activation. In the current study, the effect of p-STAT3-positive murine colon carcinoma cell line (CT26) on bone marrow-derived DCs was examined. The results showed a remarkable increase in p-STAT3 in dendritic cells (DCs) only after CT26-CM incubation. The induction of p-STAT3 in CT26-CM exposed DCs was attributed at least in part to the high levels of interleukin-6 secreted by CT26 in culture. This was also accompanied by a significant reduction in the response to the immunostimulatory adjuvant lipopolysaccharide by lowering the expression of co-stimulatory molecules CD86 and CD40. Taken together, the results suggest an inhibitory effect of CT26 colon carcinoma on DC maturation through induction of STAT3 phosphorylation. Therefore, tumor-induced p-STAT3 in DCs can be seen as a promising target for colon cancer immunotherapy. © 2012 Informa Healthcare USA, Inc.
Keywords: CD40 antigen; CD86 antigen; interleukin 6; lipopolysaccharide; STAT3 protein; animal cell; animal tissue; article; bone marrow; cancer cell culture; cancer immunotherapy; cell lineage; cell maturation; colon carcinoma; dendritic cell; down regulation; flow cytometry; mouse; nonhuman; priority journal; protein phosphorylation; Animals; Antigens, CD40; Antigens, CD86; Cell Line, Tumor; Colonic Neoplasms; Dendritic Cells; Immune Tolerance; Immunotherapy; Interleukin-6; Mice; Mice, Inbred BALB C; Neoplasm Proteins; NIH 3T3 Cells; Phosphorylation; STAT3 Transcription Factor; Murinae

Characterization of the lipopolysaccharide from Pasteurella multocida Heddleston serovar 9: Identification of a proposed bi-functional dTDP-3-acetamido-3,6-dideoxy-α-D-glucose biosynthesis enzyme - Harper, M.; St. Michael, F.; Vinogradov, E.; John, M.; Boyce, J.D.; Adler, B.; Cox, A.D. (Glycobiology, 2012)
Pasteurella multocida strains are classified into 16 different lipopolysaccharide (LPS) serovars using the Heddleston serotyping scheme. Ongoing studies in our laboratories on the LPS aim to determine the core oligosaccharide (OS) structures expressed by each of the Heddleston type strains and identify the genes and transferases required for the biosynthesis of the serovar-specific OSs. In this study, we have determined the core OS of the LPS expressed by the Heddleston serovar 9 type strain, P2095. Structural information was established by a combination of monosaccharide and methylation analyses, nuclear magnetic resonance spectroscopy and mass spectrometry revealing the following structure: The serovar 9 OS contains an inner core that is conserved among P. multocida strains with an elaborate outer core extension containing rhamnose (Rha), a D-glycero-D-manno isomer of heptose, and the unusual deoxyamino sugar, 3-acetamido-3,6-dideoxy-d-glucose (Qui3NAc). Genetic analyses of the LPS outer core biosynthesis locus revealed that in addition to the glycosyltransferases predicted to transfer the sugars to the nascent LPS molecule, the locus also contained the complete set of genes required for the biosynthesis of the nucleotide sugar donors dTDP-Rha and dTDP-Qui3NAc. One of the genes identified as part of the dTDP-Qui3NAc biosynthesis pathway, qdtD, encodes a proposed bi-functional enzyme with N-terminal amino acid identity to dTDP-4-oxo-6-deoxy-d-glucose-3,4-oxoisomerase and C-terminal amino acid identity to dTDP-3-oxo-6-deoxy-D-glucose transacetylase. © The Author 2011. Published by Oxford University Press. All rights reserved.
Keywords: 3 acetamido 3,6 dideoxy alpha dextro glucose; bacterium lipopolysaccharide; glucose derivative; glycosyltransferase; heptose; monosaccharide; rhamnose; thymidine diphosphate; unclassified drug; amino terminal sequence; article; bacterial gene; bacterial genetics; bacterial strain; carbohydrate analysis; carboxy terminal sequence; controlled study; genetic analysis; gluconeogenesis; mass spectrometry; methylation; nonhuman; nuclear magnetic resonance spectroscopy; nucleotide sequence; Pasteurella multocida; Pasteurella multocida serovar 9; priority journal; qdtD gene; Amino Acid Sequence; Bacterial Proteins; Carbohydrate Conformation; Carbohydrate Sequence; Deoxy Sugars; Genes, Bacterial; Genetic Loci; Glycosyltransferases; Lipopolysaccharides; Mass Spectrometry; Molecular Sequence Data; Pasteurella multocida; Sequence Homology, Amino Acid; Thymine Nucleotides; Pasteurella multocida

Dual-source swept-source optical coherence tomography reconstructed on integrated spectrum - Chang, S.; Mao, Y.; Flueraru, C. (International Journal of Optics, 2012)
Dual-source swept-source optical coherence tomography (DS-SSOCT) has two individual sources with different central wavelengths, linewidth, and bandwidths. Because of the difference between the two sources, the individually reconstructed tomograms from each source have different aspect ratio, which makes the comparison and integration difficult. We report a method to merge two sets of DS-SSOCT raw data in a common spectrum, on which both data have the same spectrum density and a correct separation. The reconstructed tomographic image can seamlessly integrate the two bands of OCT data together. The final image has higher axial resolution and richer spectroscopic information than any of the individually reconstructed tomography image. Copyright © 2012 Shoude Chang et al.

Real-time control of angioplasty balloon inflation based on feedback from intravascular optical coherence tomography: Experimental validation on an excised heart and a beating heart model - Azarnoush, H.; Vergnole, S.; Boulet, B.; Sowa, M.; Lamouche, G. (IEEE Transactions on Biomedical Engineering, 2012)
We report on real-time control of balloon inflation inside porcine arteries. In the first step, experiments were done in a coronary artery of an excised heart. In the second step, experiments were done in a beating heart setup providing conditions very close to in vivo conditions without the complications. A programmable syringe pump was used to inflate a compliant balloon in arteries, while intravascular optical coherence tomography (IVOCT) monitoring was performed. In a feedback loop, IVOCT images were processed to provide the balloon diameter values in real time to control the pump action in order to achieve a target diameter. In different experiments, various flow rates and target diameters were used. In the excised heart experiment, there was good convergence to target diameters resulting in a satisfactory balloon inflation control. In the beating heart experiment, there were oscillations in the diameter values due to cyclic arterial contractions. In these experiments, the control system maintained diameter averages satisfactorily close to predetermined target values. Real-time control of balloon inflation could not only provide a safer outcome for angioplasty procedures, but could also provide additional information for diagnostics since it implicitly provides information about the artery response to the inflation process. © 1964-2012 IEEE.
Keywords: Angioplasty; Balloon inflation; Beating heart; Coronary arteries; Experimental validations; Feed-back loop; In-vivo; Inflation process; Intravascular; Programmable syringe pump; Real time; Target values; Balloons; Control; Experiments; Optical tomography; Real time control; Heart; animal experiment; artery constriction; article; balloon catheter; control system; controlled study; feedback system; flow rate; heart beat; heart surgery; nonhuman; optical coherence tomography; percutaneous transluminal angioplasty; syringe; Algorithms; Angioplasty, Balloon; Animals; Feedback; Heart; Models, Cardiovascular; Pressure; Swine; Tomography, Optical Coherence

Soot emission measurement in flares by Sky-LOSA: Reduction of uncertainty in field measurements - Devillers, R.W.; Thomson, K.A.; Johnson, M.R. (Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA, 2012)
Sky-LOSA, an extension of Line-of-Sight Attenuation (LOSA) that is commonly used in laboratory-scale experiments for soot concentration measurements, was applied to a small flare in Poza Rica, Mexico. An average soot emission rate of 057 g/sec was obtained from 1.5 min of data. The uncertainty associated to velocity measurement was studied. Using a single ensemble averaged velocity in place of instantaneous velocity measurements synchronized with transmissivity measurements led to a 13% underestimation of the average soot emission rate. Uncertainty associated with integration along the optical axis was 7%. Sky-LOSA remains promising for investigation of particulate matter emissions in flares. This is an abstract of a paper presented at the 105th AWMA Annual Conference and Exhibition (San Antonio, TX 6/19-22/2012).

From laterally modulated two-dimensional electron gas towards artificial graphene - Nádvorník, L.; Orlita, M.; Goncharuk, N.A.; Smrčka, L.; Novák, V.; Jurka, V.; Hruška, K.; Výborný, Z.; Wasilewski, Z.R.; Potemski, M.; Výborný, K. (New Journal of Physics, 2012)
Cyclotron resonance has been measured in far-infrared transmission of GaAs/Al xGa 1-xAs heterostructures with an etched trigonal lateral superlattice intended to mimic graphene with lattice constant of the order of 100 nm (about 1000 times larger than that of natural graphene). Nonlinear dependence of the resonance position on magnetic field was observed, as well as its splitting into several modes. Our explanation, based on a perturbative calculation, describes the observed phenomena as a weak effect of the lateral potential on the twodimensional electron gas. Using this approach, we found a correlation between parameters of the lateral patterning and the created effective potential and obtained thus insights into how the electronic miniband structure has been tuned. The miniband dispersion was calculated using a simplified model and allowed us to formulate four basic criteria that have to be satisfied to reach graphene-like physics in such systems. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.
Keywords: Effective potentials; Far-infrared; GaAs; Lateral patterning; Lateral superlattice; Miniband structures; Minibands; Nonlinear dependence; Perturbative calculations; Resonance position; Electron gas; Magnetic fields; Graphene

Optical simulation and fabrication of periodic triangular gratings for the enhancement of photovoltaic solar panels - Dey, R.; Bordatchev, E.V.; Tauhiduzzaman, M.; Reshef, H. (SPIE - International Society for Optical Engineering. Proceedings, 2012)
The solar energy industry strives to produce more and more efficient and yet cost effective photovoltaic (PV) panels. Integration of specific micro/nano optical structures on the top surface of the PV panels is one of the efficient ways to increase their PV performance through enhancing light trapping and in-coupling. In this study, periodic triangular gratings (PTGs) in polymethyl methacrylate (PMMA) were numerically simulated and optimized. The goal of this study is to enhance the ability of solar panels to convert maximum obtainable amount of solar energy by improving the optical in-coupling of light to PV material. Initial optical simulation results shown that a flat PV panel (without any enhancing micro-optical structures) exhibits an average incident light power of 0.327 W over a range of the incident light angles between 15° and 90°. Introduction of the PTG allows capturing the incoming sunlight and reflecting it back onto the PV material for a second or more chances for absorption and conversion into electricity. The light trapping and redirection is achieved through the total internal reflection (TIR) phenomenon. Geometry of the PTG was initially optimized with respect to an incident sunlight orientation of 15°, 30°, 45°, 60°, 75°, and 90°. Optical performance of the particular optimized PTGs was analyzed over daylight conditions and several optical parameters, such as average incident power and intensity, were calculated when sunlight orientation angle was changing from 15° to 90°. By adding the PTG optimized for 15° incidents light, an average incident power of 0.342 W was achieved (4.6% improvement of optical performance). Functional PTG prototypes were fabricated with optical surface quality (below 10 nm R a). The simulation results allow understanding how the overall daytime photovoltaic performance of solar panels can be improved. © 2012 SPIE.
Keywords: Cost effective; Energy industry; Incident light; Incident light power; Incident power; Light-trapping; Micro-optical structure; Optical parameter; Optical performance; Optical simulation; Optical structures; Optical surfaces; Orientation angles; Photovoltaic; Photovoltaic panels; Photovoltaic performance; PV panel; PV performance; Solar panels; Top surface; Total internal reflections; Triangular gratings; Computer simulation; Microfabrication; Optimization; Photonic devices; Photovoltaic cells; Refractive index; Solar concentrators; Photovoltaic effects

The central blue straggler population in four outer-halo globular clusters - Beccari, G.; Lützgendorf, N.; Olczak, C.; Ferraro, F.R.; Lanzoni, B.; Carraro, G.; Stetson, P.B.; Sollima, A.; Boffin, H.M.J. (The Astrophysical Journal, 2012)
Using Hubble Space Telescope/Wide Field Planetary Camera 2 data, we have performed a comparative study of the Blue Straggler Star (BSS) populations in the central regions of the globular clusters (GCs) AM 1, Eridanus, Palomar 3, and Palomar 4. Located at distances R GC > 50kpc from the Galactic center, these are (together with Palomar 14 and NGC2419) the most distant clusters in the halo. We determine their color-magnitude diagrams and centers of gravity. The four clusters turn out to have similar ages (10.5-11Gyr), significantly smaller than those of the inner-halo globulars, and similar metallicities. By exploiting wide-field ground-based data, we build the most extended radial density profiles from resolved star counts ever published for these systems. These are well reproduced by isotropic King models of relatively low concentration. BSSs appear to be significantly more centrally segregated than red giants in all GCs, in agreement with the estimated core and half-mass relaxation times which are smaller than the cluster ages. Assuming that this is a signature of mass segregation, we conclude that AM 1 and Eridanus are slightly dynamically more evolved than Pal 3 and Pal 4. © 2012. The American Astronomical Society. All rights reserved.

Evolution of space charges and conductivity with dc aging of polyethylene-synthetic and natural clay composites - Abou-Dakka, M. (Journal of Nanomaterials, 2012)
The evolution of the space charge and conductivity with DC poling of two types of polypropylene-(PP-) based nanocomposites (PNCs) was investigated. The PNCs were manufactured with different concentrations of synthetic and natural organoclays. The optimal concentrations of nanofiller that can efficiently mitigate the space charge with DC aging time were 2-wt% for PP-natural-clay and between 2 and 4 wt% for the PP-synthetic-clay. Above these percentages charge transport through overlapping of nanoparticles can occur due to the interaction zone of double layers formed at the nanoparticle/host material interfaces. Under DC field the overlapping increases the conductivity of PNCs and minimizes the benefit of incorporating nanofillers into PP. The total charge stored in unfilled PP increased continuously with time reaching a maximum around 5000 h before decreasing but it also changed slightly in all filled specimens. It was perceived that the smaller the size of nanofiller platelets the more efficient the charge mitigation. The conductivity of specimens containing 6 wt% of natural clay and 8 wt% of synthetic clay reached ≈6 times the level of the unfilled PP. This observation could be related and due to the crossing of the percolation threshold for these composites. © 2012 Mahmoud Abou-Dakka.
Keywords: Aging time; DC field; Double layers; Interaction zone; Material interfaces; Nano-fillers; Nanofiller; Natural clays; Optimal concentration; Organoclays; Percolation thresholds; Synthetic clays; Total charge; Interfaces (materials); Polypropylenes; Thermoplastics

Thermo-mechanical properties of 5-harness satin fabric composites - Khoun, L.; Challagulla, K.; Hubert, P. (Journal of Composite Materials, 2012)
The use of woven textile reinforcements in composite structures increased significantly in the past decades due to their interesting properties over unidirectional fibres. Therefore, the prediction of the thermo-mechanical properties of woven fabric composites is essential from a design and manufacturing standpoint. A micromechanical approach based on finite element method that utilizes three-dimensional unit cell was applied to predict the effective properties of a periodic woven fabric composite material. Using the resin processing properties models such as cure kinetics, shrinkage, glass transition temperature and elastic modulus models, the development of the periodic woven fabric composite material thermo-mechanical properties, as the cure progresses was predicted. The residual strains and stresses generated in the composite unit cell during the cure were also predicted and linked with the development of the material properties. The effective properties of the cured woven fabric composite material were compared to the one of an equivalent cross-ply composite material to verify the validity of neglecting the fibre waviness while modelling woven fabric composite. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
Keywords: Cross-ply; cure; Cure kinetics; Cure progress; Effective property; Elastic properties; Fabric composites; Material property; Micromechanical approach; Residual strains; Resin processing; Thermomechanical properties; Three-dimensional units; Unit cells; Woven fabric composites; Woven textiles; Biomechanics; Composite materials; Composite micromechanics; Curing; Elasticity; Finite element method; Micromechanics; Structural design; Weaving

A VL single-domain antibody library shows a high-propensity to yield non-aggregating binders - Hussack, G.; Keklikian, A.; Alsughayyir, J.; Hanifi-Moghaddam, P.; Arbabi-Ghahroudi, M.; Van Faassen, H.; Hou, S.T.; Sad, S.; MacKenzie, R.; Tanha, J. (Protein Engineering, Design and Selection, 2012)
A synthetic human VL phage display library, created by the randomization of all complementarity-determining regions (CDRs) in a V L scaffold, was panned against three test antigens to determine the propensity of the library to yield non-aggregating binders. A total of 22 binders were isolated against the test antigens and the majority (20) were monomeric. Thus, human VL repertoires provide an efficient source of non-aggregating binders and represent an attractive alternative to human V H repertoires, which are notorious for containing high proportions of aggregating species. Moreover, the solubility of VLs, in contrast to VHs, appears much less CDR dependent. © The Author 2012. Published by Oxford University Press.
Keywords: Antibody library; Complementarity-determining regions; non-aggregating; Phage display libraries; Single domains; Antibodies; Antigens; Scaffolds; Binders; antibody; bacterial antigen; bacterial protein; bacterial toxin; immunoglobulin light chain; single chain fragment variable antibody; toxB protein, Clostridium difficile; antibody library; antigen expression; article; codon; controlled study; dissociation; enzyme linked immunosorbent assay; human; polyacrylamide gel electrophoresis; priority journal; scanning electron microscopy; solubility; amino acid sequence; antibody affinity; chemistry; genetics; metabolism; molecular cloning; molecular genetics; nucleotide sequence; peptide library; protein binding; Amino Acid Sequence; Antibody Affinity; Antigens, Bacterial; Bacterial Proteins; Bacterial Toxins; Base Sequence; Cloning, Molecular; Enzyme-Linked Immunosorbent Assay; Humans; Immunoglobulin Light Chains; Molecular Sequence Data; Peptide Library; Protein Binding; Single-Chain Antibodies

Mitigation of transient meteor events in sodium layer by TMT NFIRAOS - Herriot, G.; Irvin, C. (SPIE - International Society for Optical Engineering. Proceedings, 2012)
NFIRAOS Small meteors usually burn up near the bottom of the sodium layer. Meteor trails can lead to temporary dramatic changes in the altitude of the sodium layer. This altitude change is very rapid, typically over 1 second, and after some unpredictable period of 10-20 seconds, can transition back to the nominal mean altitude also in about 1 second. The altitude change is very drastic and can jump by up to 1 km which, on the face of it, would cause 4 micrometers defocus errors on LGS WFS measurements for a 30-m telescope, unless properly tracked. Measurements by the UBC Lidar detected ~20 meteor trails / hour, and of these, 1-2 are significant events. We report on a full end-to-end Simulink simulation for TMT NFIRAOS including: meteor events measured by the UBC Lidar; on-instrument NGS focus sensor running at 90 Hz (median sky coverage frame rate); optimal temporal blending with LGS WFS focus measurements; LGS WFS centroiding matched filter update and Truth WFS update very 3s; full trombone servo model including non-linear focus range vs stage position. We optimized our control architecture and traded off motor power dissipation versus residual wavefront error and Shack-Hartmann spot displacement and found range tracking errors induce 12 nm WFE in normal conditions and brief (1s) jumps of 30-80 nm WFE at the beginning and ending of meteor transients. © 2012 SPIE.
Keywords: Burn up; Centroiding; Control architecture; Defocus; Focus measurement; Focus sensors; Frame rate; Meteor trails; Meteors; NFIRAOS; Normal condition; Shack-Hartmann; Simulink simulations; Sky coverage; Sodium layer; Spot displacement; TMT; Tracking errors; Wavefront errors; Blending; Computer simulation; Errors; Ionization of gases; Magnetohydrodynamics; Optical radar; Optimization; Sodium; Electric appliances

ALMA band 3 cartridge maintenance plan - Yeung, K.; Seifried, K.; Randolph, W. (SPIE - International Society for Optical Engineering. Proceedings, 2012)
Under the "Memorandum of Understanding between the National Radio Astronomy Observatory (NRAO)/Associated Universities Incorporated (AUI), Herzberg Institute of Astrophysics (HIA) and the University of Calgary related to Canadian ALMA Construction Phase Work Packages", HIA is committed to deliver a suite of seventy-three Band 3 100 GHz receiver cartridges to the ALMA Project. After the acceptance of each cartridge at the Front End Integration Centers, HIA is responsible to perform any post-delivery maintenance, repair or rework of the cartridges for a warranty period of up to one year. This paper defines a framework for the maintenance and repair services for the Band 3 cartridges after the post-delivery warranty period has expired. © 2012 SPIE.
Keywords: 100 GHz; Construction phase; Front end; Maintenance and operation; Maintenance plans; Memorandum of understanding; Repair services; Test systems; University of Calgary; Warranty period; Work packages; Astrophysics; Project management; Radio astronomy; Repair; Systems engineering; Projectiles

Evidence for a non-universal stellar initial mass function in low-redshift high-density early-type galaxies - Dutton, A.A.; Mendel, J.T.; Simard, L. (Monthly Notices of the Royal Astronomical Society: Letters, 2012)
We determine an absolute calibration of stellar mass-to-light ratios for the densest ≃3 per cent of early-type galaxies in the local Universe (redshift z ≃ 0.08) from Sloan Digital Sky Survey (SDSS) Data Release 7. This sample of ~4000 galaxies has, assuming a Chabrier initial mass function (IMF), effective stellar surface densities Σe > 2500M ⊙ pc -2, stellar population synthesis (SPS) stellar masses log10(M SPS/M ⊙) < 10.8 and aperture velocity dispersions of σap = 168 +37 -34 km s -1 (68 per cent range). In contrast to typical early-type galaxies, we show that these dense early-type galaxies follow the virial Fundamental Plane, which suggests that mass follows light. With the additional assumption that any dark matter does not follow the light, the dynamical masses of dense galaxies provide a direct measurement of stellar masses. Our dynamical masses (M dyn), obtained from the spherical Jeans equations, are only weakly sensitive to the choice of anisotropy (β) due to the relatively large aperture of the SDSS fibre for these galaxies: R ap - 1.5R e. Assuming isotropic orbits (β = 0), we find a median log10(M dyn/M SPS) = 0.233 ± 0.003, consistent with a Salpeter IMF, while more bottom-heavy IMFs and standard MilkyWay IMFs are strongly disfavoured. Our results are consistent with, but do not require, a dependence of the IMF on dynamical mass or velocity dispersion. We find evidence for a colour dependence to the IMF such that redder galaxies have heavier IMFs with Mdyn/MSPS α (g - r) 1.13 ±0.09. This may reflect a more fundamental dependence of the IMF on the age or metallicity of a stellar population, or the density at which the stars formed. © 2012 The Authors. Monthly Notices of the Royal Astronomical Society © 2012 RAS.

Characteristics of gadolinia-doped ceria films deposited by spray pyrolysis - Halmenschlager, C.M.; Neagu, R.; De Fraga Malfatti, C.; Bergmann, C.P. (Materials Science and Technology Conference and Exhibition 2012, MS and T 2012, 2012)
Nowadays the challenges on SOFC are to find a way to produce good quality electrolyte, which does not need sintering at high temperature. This work presents the results of a process optimization applied to gadolinia-doped ceria thin films deposited by spray pyrolysis (SP). The aim of this work was to achieve thin, dense, and continuous CGO coatings, which may serve as electrolyte for SOFC. Dense substrates were used as substrates for the deposition. Cerium ammonium nitrate and gadolinium acetylacetonate were used as precursors' salts. Parameters such as gas flow, liquid flow and temperature were studied. Controlling these parameters, thin, dense, crack-free films could be produced on dense and porous substrates. X-ray diffraction (XRD) analysis showed that the films were crystalline after the deposition without requiring post-deposition heat treatment. Van der Pauw technique showed that the produced films have good conductivity, suitable for use as intermediate temperature solid oxide fuel cell electrolytes.
Keywords: Acetylacetonates; Cerium ammonium nitrates; Gadolinia doped ceria; Gadolinium doped ceria; Intermediate temperature solid oxide fuel cell; Porous substrates; Postdeposition heat treatment; Van der Pauw technique; Deposits; Electrolytes; Exhibitions; Gadolinium; Ionic conductivity; Materials science; Optimization; Sintering; Solid oxide fuel cells (SOFC); Spray pyrolysis; Thermal spraying; Thin films; Vapor deposition

Fast light-emitting silicon-germanium nanostructures - Lockwood, D.J.; Wu, X.; Baribeau, J.-M.; Modi, N.; Tsybeskov, L. (ECS Transactions, 2012)
Epitaxially-grown three-dimensional Si/SiGe nanostructures produce photoluminescence and electroluminescence in the desired spectral range of 1.3-1.6 μm. We show that by controlling and modifying such Ge-rich SiGe nanoclusters during growth it is possible to fabricate very fast and hence more efficient SiGe light-emitting devices. Models for the physics of carrier recombination in these Si/SiGe nanostructures are presented, and a new route toward CMOS compatible light emitters is proposed. ©The Electrochemical Society.
Keywords: Carrier recombination; CMOS Compatible; Light emitters; Light emitting devices; Si/SiGe; Silicon Germanium; Spectral range; Germanium; Silicon alloys; Nanostructures

Acoustic upgrades to wind tunnels at the National Research Council Canada - Syms, G.F. (18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference), 2012)
Airframe noise is growing a concern for aircraft manufacturers, operators and commu- nities. The ability to determine the location and strength of noise sources on an aircraft or its components allows noise reduction strategies to be developed which can have sig- nificant impact on the overall noise signature of the aircraft. Phased-microphone array measurement technologies have become an effective tool in noise source localization for aerospace configurations. With the growing national need to address airframe noise is- sues, the National Research Council Canada upgraded two of its wind tunnels to provide a better acoustic environment to make phased-array measurements. The first facility to be upgraded in 2009 was the 0.9m 3/4-open jet low speed research tunnel in which the original metal turning vanes on the corners bounding the test section were replaced with vanes lined with acoustic foam. This reduced the background noise in the test section by 5 - 10dB depending upon the frequency with little reduction in maximum tunnel speed. The second facility to receive an acoustic treatment was the 2m x 3m closed circuit tunnel in 2011. For this facility, an acoustic liner was developed for the test section which allowed the microphones to be recessed out of the flow and decreased the reverberant nature of the hard-walled tunnel. All walls of the tunnel were covered with acoustic foam-filled boxes covered with a stainless steel mesh. This reduced the background noise measured by the recessed microphone array by 15 - 20dB compared to a flush mounted array. In each up-graded facility, an aeroacoustic test of a two-wheel main landing gear of a business jet was carried out (the first at 1/3rd-scale and the second at full scale). Results in the large tunnel show accurate noise source localization with repeatability of 0.15dB for the loudest source and 0.25dB for the second loudest noise source. The two successful wind tunnel entries show the effectiveness of the two wind tunnel acoustic upgrades. © 2012 by Government of Canada.
Keywords: Acoustic environment; Acoustic treatment; Aerospace configurations; Aircraft manufacturers; Array measurements; National Research Council; Reduction strategy; Stainless steel mesh; Aeroacoustics; Aircraft; Airframes; Landing gear (aircraft); Microphones; Noise abatement; Research; Structural frames; Wind tunnels; Acoustic noise

Cyclic voltammetry of Zn/Zn(II) couple in dicyanamide anion and bis-(trifluoromethylsulfonyl)imide anion based ionic liquids - Xu, M.; Ivey, D.G.; Qu, W.; Xie, Z.; Bing, Y.H. (ECS Transactions, 2012)
The electrochemistry of a Zn/Zn(II) couple was studied and compared in four kinds of room temperature ionic liquids (RTILs) (1-butyl-1-methylpyrrolidinium dicyanamide (BMP-DCA), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide (EMI-TFSI), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (BMP-TFSI) and 1-methyl-1-pentylpyrrolidinium bis(trifluoromethanesulfonyl)imide (MPP-TFSI)), with the aim of screening desirable RTILs as replacements for traditional aqueous electrolytes for Zn rechargeable batteries. Cyclic voltammetry was used to study the reversibility and cyclability of Zn redox in each RTIL. The morphology of Zn deposits prepared from each RTIL was characterized by scanning electron microscopy. The results show that Zn redox has the best cyclability in the DCA-based RTIL, with the Zn deposit morphology characterized by finely dispersed rods composed of granular Zn particles (∼50-100 nm in size). In TFSI-based ionic liquids, the Zn/Zn(II) couple reaction had a higher current density than that in the DCA-based ionic liquid, implying different electron transfer processes. BMP-DCA and EMI-TFSI are promising RTILs worthy of further investigation. © The Electrochemical Society.
Keywords: Aqueous electrolyte; Bis(trifluoromethane sulfonyl)imide; Dicyanamide; Dicyanamide anion; Electron transfer process; Room temperature ionic liquids; Zn deposits; Zn particles; Cyclic voltammetry; Deposits; Morphology; Particles (particulate matter); Scanning electron microscopy; Zinc; Zinc deposits; Ionic liquids

A high-resolution study of the H I-H 2 transition across the perseus molecular cloud - Lee, M.-Y.; Stanimirović, S.; Douglas, K.A.; Knee, L.B.G.; Di Francesco, J.; Gibson, S.J.; Begum, A.; Grcevich, J.; Heiles, C.; Korpela, E.J.; Leroy, A.K.; Peek, J.E.G.; et al. (The Astrophysical Journal, 2012)
To investigate the fundamental principles of H 2 formation in a giant molecular cloud, we derive the H I and H 2 surface density (Σ H I and Σ H2) images of the Perseus molecular cloud on sub-pc scales (0.4pc). We use the far-infrared data from the Improved Reprocessing of the IRAS Survey and the V-band extinction image provided by the COMPLETE Survey to estimate the dust column density image of Perseus. In combination with the H I data from the Galactic Arecibo L-band Feed Array H I Survey and an estimate of the local dust-to-gas ratio, we then derive the Σ H2 distribution across Perseus. We find a relatively uniform Σ H I6-8 Mpc -2 for both dark and star-forming regions, suggesting a minimum H I surface density required to shield H 2 against photodissociation. As a result, a remarkably tight and consistent relation is found between Σ H2/Σ H I and Σ H I + Σ H2. The transition between the H I- and H 2-dominated regions occurs at N(H I) + 2N(H 2) (8-14)× 10 20cm -2. Our findings are consistent with predictions for H 2 formation in equilibrium, suggesting that turbulence may not be of primary importance for H 2 formation. However, the importance of a warm neutral medium for H 2 shielding, an internal radiation field, and the timescale of H 2 formation still remain as open questions. We also compare H 2 and CO distributions and estimate the fraction of "CO-dark" gas, f DG 0.3. While significant spatial variations of f DG are found, we do not find a clear correlation with the mean V-band extinction. © 2012. The American Astronomical Society. All rights reserved..

Proton Conductivity of Aromatic Polymers - Liu, B.; Guiver, M.D. (Solid State Proton Conductors: Properties and Applications in Fuel Cells, 2012)

Microstructure and high temperature tensile properties of wide gap brazed cobalt based superalloy X-40 - Henhoeffer, T.; Huang, X.; Yand, S.; Au, P.; Nagy, D. (Energy Materials: Materials Science and Engineering for Energy Systems, 2012)
Wide gap brazing (WGB) of X-40 cobalt based superalloy was conducted in this study using BNi-9 braze alloy with X-40 and IN738 additive alloys. A groove was machined into X-40 bars with a nominal width of 6?35 mm before filler application. Following brazing at 1200°C for 15 min, the microstructure of the as brazed joints was examined using SEM, EDS and nanoindentation technique. Both WGB joints with X-40 and IN783 additive alloys contained primary matrix phase in addition to a number of boron containing phases which assumed either eutectic or discrete forms. Nanoindention testing revealed that these boron containing phases exhibited hardness values several times higher than the base alloy and matrix phase contributing to the embrittlement of the braze joint. Porosity was also observed in both types of WGB braze joints, the degree of which was greatest in the braze joints with IN738 additive alloy. Tensile testing at 950uC showed that the yield strength of both WGB joints was higher than that of the baseline specimens while the ultimate tensile strength of the WGB joints was lower than that of the baseline X-40. The ductility of the WGB joints was significantly inferior to that of the baseline X-40, particularly for WGB with IN 738 additive alloy. © 2010 Institute of Materials, Minerals and Mining.
Keywords: Cobalt-based superalloy; High temperature tensile properties; IN738; Microstructure characterisation; Nanoindentation techniques; Ultimate tensile strength; Wide-gap brazing; X-40; Boron; Cerium alloys; Cobalt; Gas turbines; High temperature properties; Microstructure; Superalloys; Tensile strength; Tensile testing; Brazing

Compression moulding of discontinuous-fibre carbon/PEEK composites: Study of mechanical properties - Selezneva, M.; Picher-Martel, G.-P.; Landry, B.; Trudel-Boucher, D.; Roy, S.; Khoun, L.; Hojjati, M.; Lessard, L.; Hubert, P. (International SAMPE Technical Conference, 2012)
A new multi-disciplinary study is being conducted to systematically evaluate, characterize and model the moulding process and mechanical properties of composites manufactured fro mrandomly-oriented carbon/PEEK chopped strips. The heterogeneous meso-structure of this material is expected to give rise to unique material behaviour, which is not entirely accounted for in the current ASTM standards for mechanical testing. This paper presents results of a sensitivity study aimed to evaluate the dependence of measured properties on the size of the coupon gauge section. Coupons of different widths (12.5 - 50 mm) were cut from compression moulded flat panels of randomly oriented chopped strips 25 mm in length and were subjected to quasi-static tensile loading. Results did not show any noticeable effect of the coupon width on the measured properties. Tensile strength and stiffness were found to be substantially lower than those of quasi-isotropic continuous fiber laminates, 59 % and 26 % lower, respectively.
Keywords: ASTM Standards; Carbon/PEEK; Flat panel; Material behaviour; Measured properties; Mesostructures; Moulding process; Multi-disciplinary; Properties of composites; Quasi-static; Sensitivity studies; Tensile loading; Compression molding; Exhibitions; Mechanical testing; Mechanical properties

Term MRI for small preterm babies: Do parents really want to know and why has nobody asked them? - Pearce, R.; Baardsnes, J. (Acta Paediatrica, International Journal of Paediatrics, 2012)
Keywords: carbon dioxide; nitrous oxide; bacterial infection; blood transfusion; brain hemorrhage; case report; cerebellum injury; child; family stress; female; gestational age; human; infant; intestine perforation; mycosis; newborn intensive care; newborn mortality; nuclear magnetic resonance imaging; parental attitude; patient education; personal experience; positive end expiratory pressure; prematurity; preschool child; priority journal; review; septic shock; ventilator; Brain Injuries; Cerebellar Cortex; Cerebral Hemorrhage; Female; Health Knowledge, Attitudes, Practice; Humans; Infant, Newborn; Infant, Premature; Infant, Premature, Diseases; Infection; Intensive Care Units, Neonatal; Magnetic Resonance Imaging; Parents; Prognosis; Shock, Septic; Twins

Probabilistic risk analysis for aircraft structures with limited in-service damages - Liao, M.; Bombardier, Y.; Renaud, G. (28th Congress of the International Council of the Aeronautical Sciences 2012, ICAS 2012, 2012)
This paper presents some recent results of NRC research on risk assessment for aircraft structures. First, this paper briefly reviews the Canadian Forces (CF) risk assessment requirements related to aircraft structural life assessment. Because the single flight probability of failure (SFPOF) (instantaneous failure rate) is an important parameter used in aircraft risk assessment, a critical review of different SFPOF definitions and calculations is presented. As the size of the CF aircraft fleet is relatively small, one common issue encountered during risk assessment is that only a limited number of inservice damage findings are available. Several methods are discussed for preparing input data, especially the initial crack size distribution (ICSD), from small samples for structural risk analysis. To demonstrate one of the in-service damage based methods, a risk analysis case study is presented, in which limited in-service damage findings were used to calculate the SFPOF at a wing location, in support of the CF risk-based decision-making on maintenance actions and the operational life limit.
Keywords: Aircraft structure; CP-140; Damage tolerance analysis; Maintenance Action; Operational life; Probabilistic risk analysis; Probability of failure; Structural risks; Aerodynamics; Aircraft; Aircraft manufacture; Airframes; Fits and tolerances; Risk analysis; Risk assessment; Location based services

The resonant trans-Neptunian populations - Gladman, B.; Lawler, S.M.; Petit, J.-M.; Kavelaars, J.; Jones, R.L.; Parker, J.W.; Van Laerhoven, C.; Nicholson, P.; Rousselot, P.; Bieryla, A.; Ashby, M.L.N. (Astronomical Journal, 2012)
The trans-Neptunian objects (TNOs) trapped in mean-motion resonances with Neptune were likely emplaced there during planet migration late in the giant-planet formation process. We perform detailed modeling of the resonant objects detected in the Canada-France Ecliptic Plane Survey (CFEPS) in order to provide population estimates and, for some resonances, constrain the complex internal orbital element distribution. Detection biases play a critical role because phase relationships with Neptune make object discovery more likely at certain longitudes. This paper discusses the 3:2, 5:2, 2:1, 3:1, 5:1, 4:3, 5:3, 7:3, 5:4, and 7:4 mean-motion resonances, all of which had CFEPS detections, along with our upper limit on 1:1 Neptune Trojans (which is consistent with their small population estimated elsewhere). For the plutinos (TNOs in the 3:2 resonance) we refine the orbital element distribution given by Kavelaars et al. in 2009 and show that steep H-magnitude distributions (N(H)10 αH, with α = 0.8-0.9) are favored in the range H g = 8-9, and confirm that this resonance does not share the inclination distribution of the classical Kuiper Belt. We give the first population estimate for the 5:2 resonance and find that, to within the uncertainties, the population is equal to that of the 3:2 (≃13,000 TNOs with H g < 9.16), whereas the 2:1 population is smaller by a factor of 3-4 compared to the other two resonances. We also measure significant populations inhabiting the 4:3, 5:3, 7:3, 5:4, 7:4, 3:1, and 5:1 resonances, with H g < 9.16 (D > 100km) populations in the thousands. We compare our intrinsic population and orbital element distributions with several published models of resonant-TNO production; the most striking discrepancy is that resonances beyond the 2:1 are in reality more heavily populated than in published models. © 2012. The American Astronomical Society. All rights reserved.

Electronic properties of gated triangular graphene quantum dots: Magnetism, correlations, and geometrical effects - Potasz, P.; Güçlü, A.D.; Wójs, A.; Hawrylak, P. (Physical Review B - Condensed Matter and Materials Physics, 2012)
We present a theory of electronic properties of gated triangular graphene quantum dots with zigzag edges as a function of size and carrier density. We focus on electronic correlations, spin, and geometrical effects using a combination of atomistic tight-binding, Hartree-Fock, and configuration interaction methods (TB+HF+CI), including long-range Coulomb interactions. The single-particle energy spectrum of triangular dots with zigzag edges exhibits a degenerate shell at the Fermi level with a degeneracy N edge proportional to the edge size. We determine the effect of the electron-electron interactions on the ground state, the total spin, and the excitation spectrum as a function of a shell filling and the degeneracy of the shell using TB+HF+CI for N edge<12 and approximate CI method for N edge≥12. For a half-filled neutral shell we find spin-polarized ground state for structures up to N=500 atoms in agreement with previous ab initio and mean-field calculations and in agreement with Lieb's theorem for a Hubbard model on a bipartite lattice. Adding a single electron leads to the complete spin depolarization for N edge≤9. For larger structures, the spin depolarization is shown to occur at different filling factors. Away from half-fillings excess electrons(holes) are shown to form Wigner-like spin-polarized triangular molecules corresponding to large gaps in the excitation spectrum. The validity of conclusions is assessed by a comparison of results obtained from different levels of approximations. While for the charge-neutral system all methods give qualitatively similar results, away from the charge neutrality an inclusion of all Coulomb scattering terms is necessary to produce results presented here. © 2012 American Physical Society.

Stearoyl-CoA desaturase activity modulates the activation of epidermal growth factor receptor in human lung cancer cells - Nashed, M.; Chisholm, J.W.; Ariel Igal, R. (Experimental Biology and Medicine, 2012)
Stearoyl-CoA desaturase-1 (SCD1), the main enzyme that converts saturated fatty acids into monounsaturated fatty acids, is a key factor in the mechanisms of cancer cell proliferation, survival and tumorigenesis. Evidence indicates that SCD1 activity regulates these events in part by targeting the phosphatidylinositol-3 phosphate kinase/Akt and Ras/extracellular signalregulated kinase (ERK) pathways, but the molecular mechanisms remain unknown. We now show that in H460 lung cancer cells, the suppression of SCD activity with CVT-11127, a specific small molecule SCD inhibitor, impairs the ligand-induced phosphorylation of epidermal growth factor (EGF) receptor, causing the inactivation of its downstream targets Akt, ERK and mammalian target of rapamycin. Importantly, the mitogenic response to EGF was markedly defective in SCD-depleted cancer cells. The inactivation of EGF receptor (EGFR) promoted by SCD inhibition may be caused by perturbations in the lipid microenvironment surrounding the receptor, since we detected significant alterations in the lateral mobility of plasma lipid microdomains. Finally, incubation of lung cancer cells with SCD blockers potentiated the antigrowth effect of gefitinib, an EGFR inhibitor employed in cancer treatment. Altogether, our data indicate that SCD activity may control cancer cell metabolism, proliferation and survival by modulating the EGFR→Akt/ERK signaling platforms. Our studies also suggest a value for SCD inhibitors as novel pharmacological agents in lung cancer, one of the most common and lethal forms of cancer for which therapeutic options remain very limited. © 2008 Society for Experimental Biology and Medicine.
Keywords: acyl coenzyme A desaturase 1; acyl coenzyme A desaturase inhibitor; cvt 11127; enzyme inhibitor; epidermal growth factor receptor; gefitinib; mammalian target of rapamycin; mitogen activated protein kinase; monounsaturated fatty acid; protein kinase B; saturated fatty acid; unclassified drug; article; cancer cell; cell membrane; cell metabolism; cell proliferation; cell survival; controlled study; cytotoxicity; drug effect; drug potentiation; drug sensitivity; enzyme activity; enzyme inhibition; human; human cell; lipid blood level; lung cancer; microenvironment; mitogenesis; protein phosphorylation; Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cell Transformation, Neoplastic; Extracellular Signal-Regulated MAP Kinases; Humans; Lung Neoplasms; MAP Kinase Signaling System; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Quinazolines; Receptor, Epidermal Growth Factor; Stearoyl-CoA Desaturase; TOR Serine-Threonine Kinases; Mammalia

Cryogenic mechanical design: SPIROU spectrograph - Reshetov, V.; Herriot, G.; Thibault, S.; Désaulniers, P.; Saddlemyer, L.; Loop, D. (SPIE - International Society for Optical Engineering. Proceedings, 2012)
This paper presents an overview of the PDR level mechanical and opto-mechanical design of the cryogenic spectrograph unit of the nIR spectropolarimeter (SPIROU) proposed as a new-generation instrument for CFHT. The design is driven by the need for high thermo-mechanical stability in terms of the radial velocity (RV) of 1 m/s during one night, with the requirement for thermal stability set at 1 mK/24 hours. This paper describes stress-free design of the cryogenic optical mounts, mechanical design of the custom-build cryostat, mechanical design of the optical bench, and thermal design for 1 mK thermal stability. The thermal budget was calculated using lumped-mass model thermal analysis, implemented in Modelica multi-domain modeling language. Discussion of thermal control options to achieve 1 mK thermal stability is included. © 2012 SPIE.
Keywords: Mechanical design; Modelica; Multi-domain modeling; Optical Bench; Optical Mounts; Opto-mechanical design; Radial velocity; Spectropolarimeters; Thermal budget; Thermal control; Thermal designs; Thermomechanical stability; Astronomy; Design; Infrared spectrographs; Instruments; Spectrographs; Thermoanalysis; Thermodynamic stability; Cryogenics

Feasibility studies to upgrade the Canada-France-Hawaii Telescope site for the Next Generation Canada-France-Hawaii Telescope - Szeto, K.; Angers, M.; Breckenridge, C.; Bauman, S.; Loewen, N.; Loop, D.; McConnachie, A.; Pazder, J.; Salmon, D.; Spano, P.; Stiemer, S.; Veillet, C. (SPIE - International Society for Optical Engineering. Proceedings, 2012)
The Next Generation Canada-France-Hawaii Telescope is a dedicated, 10m aperture, wide-field, fiber-fed multi-object spectroscopic facility proposed as an upgrade to the existing Canada-France-Hawaii Telescope on the summit of Mauna Kea. The Next Generation Canada-France-Hawaii Telescope baseline concept assumes the new facility is built on the existing Canada-France-Hawaii Telescope telescope pier and enclosure pier and occupies the same three dimensional exterior "footprint". Three technical studies have been planned to examine the validity of these assumptions. The technical studies are executed in series as they represent technical decision points in a logical sequence. The three technical studies in succession are: 1. Telescope Pier Study - Load Capacity and Structural Interface, 2. Enclosure Fixed Base Study - Telescope and Enclosure Configuration and Load Capacity and 3. Aero- Thermal Study - Dome Thermal Seeing and Air Flow Attenuation over the Enclosure Aperture Opening. The paper outlines the baseline facility (telescope, spectrograph and enclosure) concept and the status of these studies, and discusses the proposed telescope and enclosure configuration in terms of the redevelopment assumptions. A consolidated feasibility study report will be submitted to the CFHT Board and Science Advisory Committee in the Fall of 2012, with first light for the facility aiming to be in the early 2020s. © 2012 SPIE.
Keywords: ACI; Advisory committee; Air flow; AISC; ASCE; Baseline concepts; Dome seeing; Feasibility studies; Fixed base; Load capacity; Logical sequences; Multiobject; Structural interface; Technical decision; Technical study; Thermal study; Wide-field; Airborne telescopes; Computational fluid dynamics; Domes; Enclosures; Piers; Planning; Optical telescopes

Wind uplift performance of composite metal roof assemblies - Baskaran, A.; Molleti, S.; Ko, S.; Shoemaker, L. (Journal of Architectural Engineering, 2012)
A common factor in roof failures is wind forces, which inflict considerable damage every year, even to new roof structures. Metal roofs are a popular low-sloped roof assembly. On the basis of their layout, metal roofs can be categorized as either composite or noncomposite assemblies. In North American practice, five main test procedures - ASTM E1592, ANSI/FM 4474, UL 580, UL 1817, and CSA A123.21-04 - are used to determine the wind uplift performance of metal roofs. The fundamental differences between these test protocols lie in the way they represent wind effects on the performance of metal roofing systems. Of the five, CSA A 123.21-04 is the only one that assesses the wind uplift resistance under dynamic wind load conditions. To evaluate the wind uplift performance of noncomposite and composite metal roofing assemblies, eight assemblies with two different types of panels - SNAP-IT and MR-24 - were tested by using the CSA A123.21-04 dynamic test protocol. By relating air intrusion characteristics of the subsurface components to panel behavior, this paper shows how composite assemblies resist wind uplift pressures better than noncomposite assemblies. This paper reveals that increased air intrusion resistance of the sub surface components in composite assemblies results in increased suction resistance, decreased panel deflection, decreased stress on the panels, and increased wind uplift resistance. © 2012 American Society of Civil Engineers.
Keywords: Air intrusion; Composite assembly; Dynamic tests; Dynamic wind loads; Metal roofing system; Non-composite; Panel deflection; Wind uplift resistance; Composite materials; Metals; Roofs; Testing; Wind effects; Surface resistance

Radiation shielding materials and radiation scatter effects for interventional radiology (IR) physicians - McCaffrey, J.P.; Tessier, F.; Shen, H. (Medical Physics, 2012)
Purpose: To measure the attenuation effectiveness and minimize the weight of new non-Pb radiation shielding materials used for radiation protection by interventional radiology (IR) physicians, to compare the accuracy of the different standard measurement geometries of these materials, and to determine x-ray qualities that correspond to the scattered radiation that IR physicians typically encounter. Methods: Radiation attenuation capabilities of non-Pb materials were investigated. Typically, most studies of non-Pb materials have focused on the attenuating properties of metal powders. In this study, layers of materials incorporating non-Pb powdered compounds such as Bi2O 3, Gd2O3, and BaSO4 were measured individually, as bilayers, and as a Bi2O3-loaded hand cream. Attenuation measurements were performed in narrow-beam (fluorescence excluded) and broad beam (fluorescence included) geometries, demonstrating that these different geometries provided significantly different results. The Monte Carlo (MC) program EGSnrc was used to calculate the resulting spectra after attenuation by radiation shielding materials, and scattered x-ray spectra after 90° scattering of eight ASTM Standard primary x-ray beams. Surrogate x-ray qualities that corresponded to these scattered spectra were tabulated. Results: Radiation shielding materials incorporating Bi2O3 were found to provide equivalent or superior attenuation compared with commercial Pb-based and non-Pb materials across the 60-130 kVp energy range. Measurements were made for single layers of the Bi2O3 compound and for bilayers where the ordering was low atomic number (Z) layer closest to x-ray sourcehigh Z (Bi2O3) layer farthest from the x-ray source. Narrow-beam Standard test methods which do not include the contribution from fluorescence overestimated the attenuating capabilities of Pb and non-Pb materials. Measurements of a newly developed, quick-drying, and easily removable Bi2O3-loaded hand cream demonstrated better attenuation capabilities than commercial Bi2O3-loaded gloves. Scattered radiation measurements and MC simulations illustrated that the spectra resulting from 90° scattering of primary x-ray beam qualities can be approximated by surrogate x-ray qualities which are more representative of the radiation actually encountered by IR physicians. A table of surrogate qualities of the eight ASTM F2547-06 Standard qualities was compiled. Conclusions: New non-Pb compound materials, particularly single layers or bilayers incorporating Bi2O3, can reduce the weight of radiation protection materials while providing equivalent or better protection compared to Pb-based materials. Attenuation measurements in geometries that exclude the contribution from fluorescence substantially underestimate the quantity of transmitted radiation. A new Bi2O3-loaded hand cream demonstrated a novel and effective approach for hand protection. Standard testing protocols for radiation protection materials used by IR physicians specify a wider kVp range than is necessary. A more realistic range would acknowledge the lower kVp resulting from scatter and allow IR physicians to confidently utilize lighter-weight materials while still receiving adequate protection. Standards protocols incorporating the adjustments described in this work would maintain the safety of IR personnel and lessen the physical repercussions of long hours wearing unnecessarily heavy radiation protection garments. © 2012 American Association of Physicists in Medicine.
Keywords: article; equipment; equipment design; human; instrumentation; interventional radiology; materials; materials testing; methodology; physician; radiation injury; radiation protection; radiation scattering; Equipment Design; Equipment Failure Analysis; Humans; Manufactured Materials; Materials Testing; Physicians; Radiation Injuries; Radiation Protection; Radiography, Interventional; Scattering, Radiation

An analysis of the rapidly rotating Bp star HD 133880 - Bailey, J.D.; Grunhut, J.; Shultz, M.; Wade, G.; Landstreet, J.D.; Bohlender, D.; Lim, J.; Wong, K.; Drake, S.; Linsky, J. (Monthly Notices of the Royal Astronomical Society, 2012)
HD 133880 is a rapidly rotating chemically peculiar B-type (Bp) star (vsini≃ 103kms -1) and is host to one of the strongest magnetic fields of any Ap/Bp star. A member of the Upper Centaurus Lupus association, it is a star with a well-determined age of 16Myr. 12 new spectra, four of which are polarimetric, obtained from the FEROS, ESPaDOnS and HARPS instruments, provide sufficient material from which to re-evaluate the magnetic field and obtain a first approximation to the atmospheric abundance distributions of He, O, Mg, Si, Ti, Cr, Fe, Ni, Pr and Nd. An abundance analysis was carried out using zeeman, a program which synthesizes spectral line profiles for stars with permeating magnetic fields. The magnetic field structure was characterized by a colinear multipole expansion from the observed variations of the longitudinal and surface fields with rotational phase. Both magnetic hemispheres are clearly visible during the stellar rotation, and thus a three-ring abundance distribution model encompassing both magnetic poles and magnetic equator with equal spans in colatitude was adopted. Using the new magnetic field measurements and optical photometry together with previously published data, we refine the period of HD 133880 to P= 0.877476 ± 0.000009d. Our simple axisymmetric magnetic field model is based on a predominantly quadrupolar component that roughly describes the field variations. Using spectrum synthesis, we derived mean abundances for O, Mg, Si, Ti, Cr, Fe and Pr. All elements, except Mg, are overabundant compared to the Sun. Mg appears to be approximately uniform over the stellar surface, while all other elements are more abundant in the negative magnetic hemisphere than in the positive magnetic hemisphere. In contrast to most Ap/Bp stars which show an underabundance in O, in HD 133880 this element is clearly overabundant compared to the solar abundance ratio. In studying the Hα and Paschen lines in the optical spectra, we could not unambiguously detect information about the magnetosphere of HD 133880. However, radio emission data at both 3 and 6cm suggest that the magnetospheric plasma is held in rigid rotation with the star by the magnetic field and further supported against collapse by the rapid rotation. Subtle differences in the shapes of the optically thick radio light curves at 3 and 6cm suggest that the large-scale magnetic field is not fully axisymmetric at large distances from the star. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.

Metabolic consequences of hepatic steatosis in overweight and obese adolescents - Wicklow, B.A.; Wittmeier, K.D.M.; MacIntosh, A.C.; Sellers, E.A.C.; Ryner, L.; Serrai, H.; Dean, H.J.; McGavock, J.M. (Diabetes Care, 2012)
OBJECTIVE - To test the hypothesis that hepatic steatosis is associated with risk factors for type 2 diabetes in overweight and obese youth, mediated by cardiorespiratory fitness. RESEARCH DESIGN AND METHODS - This was a cross-sectional study comparing insulin sensitivity between 30 overweight and obese adolescents with hepatic steatosis, 68 overweight and obese adolescents without hepatic steatosis, and 11 healthy weight adolescents without hepatic steatosis. Cardiorespiratory fitness was determined by a graded maximal exercise test on a cycle ergometer. Secondary outcomes included presence of metabolic syndrome and glucose response to a 75-g oral glucose challenge. RESULTS - The presence of hepatic steatosis was associated with 55%lower insulin sensitivity (P = 0.02) and a twofold greater prevalence of metabolic syndrome (P = 0.001). Differences in insulin sensitivity (3.5 vs. 4.5 mU · kg -1 · min -1, P = 0.03), prevalence of metabolic syndrome (48 vs. 20%, P = 0.03), and glucose area under the curve (816 vs. 710, P = 0.04) remained between groups after matching for age, sex, and visceral fat. The association between hepatic steatosis and insulin sensitivity (β = -0.24, t = -2.29, P < 0.025), metabolic syndrome (β = -0.54, t = -5.8, P < 0.001), and glucose area under the curve (β = 0.33, t = 3.3, P < 0.001) was independent of visceral and whole-body adiposity. Cardiorespiratory fitness was not associated with hepatic steatosis, insulin sensitivity, or presence of metabolic syndrome. CONCLUSIONS - Hepatic steatosis is associated with type 2 diabetes risk factors independent of cardiorespiratory fitness, whole-body adiposity, and visceral fat mass. © 2012 by the American Diabetes Association.
Keywords: alanine aminotransferase; aspartate aminotransferase; glucose; high density lipoprotein; low density lipoprotein; triacylglycerol; adolescent; adult; article; body fat; cardiorespiratory fitness; controlled study; cross-sectional study; disease association; dysglycemia; dyslipidemia; fatty liver; female; fitness; glucose blood level; glucose intolerance; human; insulin blood level; insulin release; insulin sensitivity; intraabdominal fat; major clinical study; male; metabolic syndrome X; non insulin dependent diabetes mellitus; obesity; outcome assessment; physical activity; prevalence; risk factor; triacylglycerol blood level; waist circumference; Adolescent; Body Fat Distribution; Case-Control Studies; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Fatty Liver; Female; Humans; Insulin Resistance; Lipids; Male; Obesity; Overweight; Risk Factors

Vimentin participates in microglia activation and neurotoxicity in cerebral ischemia - Jiang, S.X.; Slinn, J.; Aylsworth, A.; Hou, S.T. (Journal of Neurochemistry, 2012)
Microglia are the 'immune cells' of the brain and their activation plays a vital role in the pathogenesis of many neurodegenerative diseases. Activated microglia produce high levels of pro-inflammatory factors, such as TNFα, causing neurotoxicity. Here we show that vimentin played a key role in controlling microglia activation and neurotoxicity during cerebral ischemia. Deletion of vimentin expression significantly impaired microglia activation in response to LPS in vitro and transient focal cerebral ischemia in vivo. Reintroduction of the functional vimentin gene back into vimentin knockout microglia restored their response to LPS. More importantly, impairment of microglia activation significantly protected brain from cerebral ischemia-induced neurotoxicity. Collectively, we demonstrate a previously unknown function of vimentin in controlling microglia activation. Microglia activation plays an important role in many neurodegenerative diseases. Here we show that impaired vimentin expression significantly reduced microglia activation in response to LPS in vitro and cerebral ischemia in vivo. These studies demonstrate a unknown function of vimentin in controlling microglia activation and neurotoxicity during cerebral ischemia. © 2012 National Research Council Canada & The Authors. Journal of Neurochemistry © 2012 International Society for Neurochemistry.
Keywords: lipopolysaccharide; tumor necrosis factor; vimentin; animal cell; animal experiment; animal model; animal tissue; article; brain infarction size; brain ischemia; cell activation; cell isolation; controlled study; gene deletion; gene expression regulation; gene overexpression; immunofluorescence; in vitro study; in vivo study; microglia; mouse; neuroprotection; neurotoxicity; nonhuman; priority journal; protein analysis; protein expression; protein function; signal transduction; Animals; Blotting, Western; Brain; Brain Ischemia; Cell Separation; Fluorescent Antibody Technique, Indirect; Image Processing, Computer-Assisted; In Situ Nick-End Labeling; Infarction, Middle Cerebral Artery; Ischemic Attack, Transient; Lipopolysaccharides; Macrophage Activation; Mice; Mice, Inbred C57BL; Mice, Knockout; Microglia; Microscopy, Confocal; Nervous System Diseases; Plasmids; Reperfusion Injury; Tetracycline; Vimentin

Procedure for direct measurement of general quantum states using weak measurement - Lundeen, J.S.; Bamber, C. (Physical Review Letters, 2012)
Recent work by Lundeen et al. directly measured the wave function by weakly measuring a variable followed by a normal (i.e., "strong") measurement of the complementary variable. We generalize this method to mixed states by considering the weak measurement of various products of these observables, thereby providing the density matrix an operational definition in terms of a procedure for its direct measurement. The method only requires measurements in two bases and can be performed in situ, determining the quantum state without destroying it. © 2012 American Physical Society.
Keywords: Density matrix; Direct measurement; In-situ; Mixed state; Operational definition; Quantum state; Weak measurements; Measurements; Quantum optics; Quantum theory

Laser cladding of high-performance CPM tool steels on hardened H13 hot-work tool steel for automotive tooling applications - Chen, J.; Xue, L. (TMS Annual Meeting, 2012)
This paper summarizes our work on laser cladding of high-vanadium carbide CPM tool steels (3V, 9V and 15V) onto hardened chromium hot-work AISI H13 tool steel with a hardness of HRc 50-55 in order to substantially enhance abrasive wear resistance, which provides a great potential for fabricating high-performance automotive tooling at affordable cost.
Keywords: AISI H13; H13 tool steel; Tooling; Carbides; Chromium; Hardening; Interfaces (materials); Laser cladding; Vanadium

Experimental results on wavefront correction using the self-coherent camera - Mas, M.; Baudoz, P.; Mazoyer, J.; Galicher, R.; Rousset, G. (SPIE - International Society for Optical Engineering. Proceedings, 2012)
The Self-Coherent Camera is dedicated to the direct detection of exoplanets. This instrument can be used as a focal plane wavefront sensor to measure static aberrations that induce speckles on the detector, which prevents the detection of faint companions. The Self-Coherent Camera creates a reference beam in the Lyot stop pupil plane in order to spatially modulate the speckle pattern with Fizeau fringes. We can then estimate for wavefront aberrations upstream of the coronagraphic mask and correct for them using a deformable mirror. Currently, the Self-Coherent Camera is combined with a deformable mirror located in the pupil plane upstream of a Four-Quadrant Phase Mask Coronagraph. In this paper, we present the formalism that explains how the Self-Coherent Camera encodes speckles and how we estimate the wavefront aberrations directly from the science image. We present numerical simulation results on speckle suppression in the focal plane. Then, we give experimental results on wavefront correction on our optical bench using a 32x32 actuators deformable mirror. We show that we can improve the contrast in the focal plane by a factor of more than 100 in the PSF wings up to 12λ/D. © 2012 SPIE.
Keywords: Coronagraphy; High angular resolutions; High contrast imaging; Instrumentation; Wavefront correction; Aberrations; Astronomy; Cameras; Computer simulation; Detectors; Focusing; Speckle; Wavefronts

Spin-forbidden Helium I transition rates - Morton, D.C.; Drake, G.W.F. (Journal of Physics: Conference Series, 2012)
We have calculated spin-forbidden transition rates in neutral helium using the spin-orbit and spin-other-orbit Breit-Pauli operators.
Keywords: Spin orbits; Spin other orbits; Transition rates; Physics; Helium

Non-contact photoacoustic tomography and ultrasonography for tissue imaging - Rousseau, G.; Blouin, A.; Monchalin, J.-P. (Biomedical Optics Express, 2012)
The detection of ultrasound in photoacoustic tomography (PAT) and ultrasonography (US) usually relies on ultrasonic transducers in contact with the biological tissue. This is a major drawback for important potential applications such as surgery and small animal imaging. Here we report the use of remote optical detection, as used in industrial laser-ultrasonics, to detect ultrasound in biological tissues. This strategy enables non-contact implementation of PAT and US without exceeding laser exposure safety limits. The method uses suitably shaped laser pulses and a confocal Fabry-Perot interferometer in differential configuration to reach quantum-limited sensitivity. Endogenous and exogenous inclusions exhibiting optical and acoustic contrasts were detected ex vivo in chicken breast and calf brain specimens. Inclusions down to 0.5 mm in size were detected at depths well exceeding 1 cm. The method could significantly expand the scope of applications of PAT and US in biomedical imaging. © 2011 Optical Society of America.
Keywords: Biological tissues; Biomedical imaging; Chicken breast; Confocal Fabry Perot interferometer; Differential configuration; Ex-vivo; Laser exposure; Laser ultrasonics; Non-contact; Optical detection; Photoacoustic tomography; Potential applications; Safety limits; Scope of application; Shaped laser pulse; Small animal imaging; Tissue imaging; Animals; Bioacoustics; Laser safety; Medical imaging; Tissue; Ultrasonic applications; Ultrasonic transducers; Ultrasonics; Ultrasonography; Photoacoustic effect; Animalia; Columba

Bacteriophages with the ability to degrade uropathogenic Escherichia Coli biofilms - Chibeu, A.; Lingohr, E.J.; Masson, L.; Manges, A.; Harel, J.; Ackermann, H.-W.; Kropinski, A.M.; Boerlin, P. (Viruses, 2012)
Escherichia coli-associated urinary tract infections (UTIs) are among the most common bacterial infections in humans. UTIs are usually managed with antibiotic therapy, but over the years, antibiotic-resistant strains of uropathogenic E. coli (UPEC) have emerged. The formation of biofilms further complicates the treatment of these infections by making them resistant to killing by the host immune system as well as by antibiotics. This has encouraged research into therapy using bacteriophages (phages) as a supplement or substitute for antibiotics. In this study we characterized 253 UPEC in terms of their biofilm-forming capabilities, serotype, and antimicrobial resistance. Three phages were then isolated (vB_EcoP_ACG-C91, vB_EcoM_ACG-C40 and vB_EcoS_ACG-M12) which were able to lyse 80.5% of a subset (42) of the UPEC strains able to form biofilms. Correlation was established between phage sensitivity and specific serotypes of the UPEC strains. The phages' genome sequences were determined and resulted in classification of vB_EcoP_ACG-C91 as a SP6likevirus, vB_EcoM_ACG-C40 as a T4likevirus and vB_EcoS_ACG-M12 as T1likevirus. We assessed the ability of the three phages to eradicate the established biofilm of one of the UPEC strains used in the study. All phages significantly reduced the biofilm within 2-12 h of incubation. © 2012 by the authors; licensee MDPI, Basel, Switzerland.
Keywords: amoxicillin plus clavulanic acid; ampicillin; cefoxitin; ceftiofur; ceftriaxone; chloramphenicol; ciprofloxacin; cotrimoxazole; kanamycin; nalidixic acid; streptomycin; sulfafurazole; tetracycline; antibiotic resistance; antibiotic sensitivity; article; bacterial genome; bacterial strain; bacterial virulence; bacteriophage; bacterium isolate; biofilm; controlled study; DNA sequence; genetic variability; nonhuman; nucleotide sequence; serotype; uropathogenic Escherichia coli; Anti-Bacterial Agents; Bacteriolysis; Biofilms; Coliphages; DNA, Viral; Female; Genome, Viral; Genotype; Humans; Microbial Sensitivity Tests; Molecular Sequence Data; Sequence Analysis, DNA; Serotyping; Uropathogenic Escherichia coli; Bacteria (microorganisms); Escherichia coli

Alessi 95 and the short-period Cepheid SU Cassiopeiae - Turner, D.G.; Majaess, D.J.; Lane, D.J.; Balam, D.D.; Gieren, W.P.; Storm, J.; Forbes, D.W.; Havlen, R.J.; Alessi, B. (Monthly Notices of the Royal Astronomical Society, 2012)
The parameters for the newly discovered open cluster Alessi 95 are established on the basis of available photometric and spectroscopic data, in conjunction with new observations. Colour excesses for spectroscopically observed B- and A-type stars near SU Cas follow a reddening relation described by E(U-B)/E(B-V) = 0.83 + 0.02E(B-V), implying a value of R=A V/E(B-V) ≃ 2.8 for the associated dust. Alessi 95 has a mean reddening of E(B-V)(B0) = 0.35 ± 0.02s.e., an intrinsic distance modulus of V 0-M V= 8.16 ± 0.04s.e. (±0.21s.d.), d= 429 ± 8pc, and an estimated age of 10 8.2yr from zero-age main sequence (ZAMS) fitting of available UBV, CCD BV, NOMAD, and Two Micron All Sky Survey JHK s observations of cluster stars. SU Cas is a likely cluster member, with an inferred space reddening of E(B-V) = 0.33 ± 0.02 and a luminosity of 〈M V〉=-3.15 ± 0.07s.e., consistent with overtone pulsation (P FM= 2.75d), as also implied by the Cepheid's light-curve parameters, rate of period increase and Hipparcos parallaxes for cluster stars. There is excellent agreement of the distance estimates for SU Cas inferred from cluster ZAMS fitting, its pulsation parallax derived from the infrared surface brightness technique and Hipparcos parallaxes, which all agree to within a few per cent. © 2012 The Authors. Monthly Notices of the Royal Astronomical Society © 2012 RAS.

More on the narrowing of impact broadened radio recombination lines at high principal quantum number - Bell, M.B. (Astrophysics and Space Science, 2012)
Recently Alexander and Gulyaev have suggested that the apparent decrease in impact broadening of radio recombination lines seen at high principal quantum number n may be a product of the data reduction process, possibly resulting from the presence of noise on the telescope spectra that is not present on the calculated comparison spectra. This is an interesting proposal. However, there are serious problems with their analysis that need to be pointed out. Perhaps the most important of these is the fact that for principal quantum numbers below n=200, where the widths are not in question, their processed generated profile widths do not fit the widths of the processed lines obtained at the telescope. After processing, the halfwidths of the generated and telescope profiles must agree below n=200 if we are to believe that the processed generated linewidths above n=200 are meaningful. Theirs do not. Furthermore, we find that after applying the linewidth reduction factors found by Alexander and Gulyaev for their noise added profiles to our generated profiles to simulate their noise adding effect, the processed widths we obtain still do not come close to explaining the narrowing seen in the telescope lines for n values in the range 200 < n < 250. It is concluded that what is needed to solve this mystery is a completely new approach using a different observing technique instead of simply a further manipulation of the frequency-switched data. © 2012 Springer Science+Business Media B.V.

Performance of dynamic azimuthing podded propulsor - Akinturk, A.; Islam, M.F.; Veitch, B.; Liu, P. (International Shipbuilding Progress, 2012)
This paper presents results and analyses of an experimental study into the effects of static and dynamic azimuthing conditions on the propulsive characteristics of a puller podded unit in open water. The model propulsor was instrumented to measure thrust and torque of the propeller, three orthogonal forces and moments on the unit, rotational speed of the propeller, azimuthing angle and azimuthing rate. The model was first tested over a range of advance coefficients at various static azimuthing angles in the range of-180° to 180°. These tests were followed by tests in which the azimuthing angle was varied dynamically at certain azimuthing rate and propeller rotational speed. A comparative study of the performance coefficients at static and dynamic azimuthing conditions in the range of-180° to 180° is presented. The performance coefficients of the propeller and the pod unit showed a strong dependence on the propeller loading and azimuthing angle. The coefficients in static azimuthing conditions fit well with a 10th order polynomial fit of the data obtained in the dynamic azimuthing condition in the corresponding azimuthing angles and advance coefficient. An uncertainty analysis of the measurements is also presented. © 2012-IOS Press and the authors. All rights reserved.
Keywords: Azimuthing; Comparative studies; Experimental studies; Global forces; Open water; Order polynomials; Performance coefficients; Podded propulsors; Propulsive performance; Propulsors; Rotational speed; Static and dynamic; Thrust and torques; Loading; Uncertainty analysis; Propellers

Germline ablation of SMUG1 DNA glycosylase causes loss of 5-hydroxymethyluracil-and UNG-backup uracil-excision activities and increases cancer predisposition of Ung-/-Msh2-/- mice - Kemmerich, K.; Dingler, F.A.; Rada, C.; Neuberger, M.S. (Nucleic Acids Research, 2012)
Deamination of cytosine (C), 5-methylcytosine (mC) and 5- hydroxymethylcytosine (hmC) occurs spontaneously in mammalian DNA with several hundred deaminations occurring in each cell every day. The resulting potentially mutagenic mispairs of uracil (U), thymine (T) or 5-hydroxymethyluracil (hmU) with guanine (G) are substrates for repair by various DNA glycosylases. Here,weshowthat targetedinactivation of the mouse Smug1 DNA glycosylase gene is sufficient to ablate nearly all hmU-DNA excision activity as judged by assay of tissue extracts from knockout mice as well as by the resistance of their embryo fibroblasts to 5-hydroxymethyldeoxyuridine toxicity. Inactivation of Smug1 when combined with inactivation of the Ung uracil-DNA glycosylase gene leads to a loss of nearly all detectable uracil excision activity. Thus, SMUG1 is the dominant glycosylase responsible for hmU-excision in mice as well as the major UNG-backup for U-excision. Both Smug1-knockout and Smug1/Ung-double knockout mice breed normally and remain apparently healthy beyond 1 year of age. However, combined deficiency in SMUG1 and UNG exacerbates the cancer predisposition of Msh2-/- mice suggesting that when both base excision and mismatch repair pathways are defective, the mutagenic effects of spontaneous cytosine deamination are sufficient to increase cancer incidence but do not preclude mouse development. © 2012 The Author(s).
Keywords: 5 hydroxymethyluracil; DNA glycosyltransferase; protein SMUG1; protein UNG; unclassified drug; uracil; animal cell; animal tissue; article; cancer susceptibility; controlled study; deamination; embryo; enzyme activity; gene; gene inactivation; knockout mouse; male; mouse; MSH2 gene; nonhuman; priority journal; SMUG1 gene; ung gene; Animals; beta-Galactosidase; Cell Line; DNA Repair; Fibroblasts; Fluorouracil; Gene Targeting; Genetic Predisposition to Disease; Longevity; Mice; Mice, Inbred C57BL; Mice, Knockout; MutS Homolog 2 Protein; Neoplasms, Experimental; Pentoxyl; Thymidine; Uracil-DNA Glycosidase; Mammalia; Mus

Correction of instrumental mass discrimination for isotope ratio determination with multi-collector inductively coupled plasma mass spectrometry - Meija, Juris; Yang, Lu; Mester, Zoltán; Sturgeon, Ralph E. (Isotopic Analysis: Fundamentals and Applications Using ICP-MS, 2012)
Keywords: Inductively coupled plasma mass spectrometry; multi-collector; isotope ratio; instrumental mass discrimination; calibration; double spike. uncertainty

π/2-Angle yao graphs are spanners - Bose, P.; Damian, M.; DouÏeb, K.; O'Rourke, J.; Seamone, B.; Smid, M.; Wuhrer, S. (International Journal of Computational Geometry and Applications, 2012)
We show that the Yao graph Y 4 in the L 2 metric is a spanner with stretch factor 8√2(26 + 23√2 ). Enroute to this, we also show that the Yao graph Y ∞4 in the L ∞ metric is a plane spanner with stretch factor 8. © 2012 World Scientific Publishing Company.

The effect of nozzle shape and configuration on bubble formation in a liquid cross flow - Jobehdar, M.H.; Gadallah, A.H.; Siddiqui, K.; Chishty, W.A. (American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM, 2012)
Gas injection into a liquid cross flow from a nozzle causes bubble formations which have potential applications in industry such as chemical plants, waste water treatment and bio- and nuclear-reactors. The purpose of this study is to experimentally investigate the effects of nozzle shape and configuration with respect to the liquid cross-flow direction, on the bubbly flow characteristics such as bubble formation, detached bubble size and frequency at different gas and liquid flow rates. The experiments were conducted in a Plexiglas two-dimensional rig using a high speed camera. High speed imaging and an image processing algorithm were used to track each individual bubble and to quantify the bubble growth as well as the detachment frequency and the bubble velocity. Back light shadowgraphy which utilizes a low intensity diffuse light source to illuminate the background was used to image bubbles. Nozzles were mounted in the test section which was designed such that the flow in this section has a two-dimensional profile. The results showed that the bubble size increases with an increase in GLR (gas to liquid flow rates ratio). Furthermore, the bubble formations and detached bubble size were strongly influenced by the nozzle shape and configuration. Copyright © 2012 by ASME.
Keywords: Bubble velocities; Cross-flow direction; Gas and liquid flows; Gas to liquids; High speed imaging; Image processing algorithm; Low-intensity; Two-dimensional profiles; Bubble formation; Chemical plants; Flow rate; Heat transfer; High speed cameras; Image processing; Light sources; Microchannels; Nozzles; Two dimensional; Liquids

Use of filler wire for laser welding of Ti-6Al-4V - Kabir, A.S.H.; Cao, X.; Wanjara, P.; Cuddy, J.; Birur, A.; Medraj, M. (Canadian Metallurgical Quarterly, 2012)
Owing to the high specific strength and excellent corrosion resistance, Ti-6Al-4V has been widely applied in aerospace industries. In this study, the welding performance of 3·2 and 5·1 mm thick Ti-6Al-4V sheets was studied using a 4 kW continuous wave Nd:YAG laser. It is found that the use of filler wire, matching the parent metal composition, can bridge the joint gap and produce full penetrated welds up to a width of 0·6 mm without cracking. The laser welds were characterised in terms of the bead geometry, defects, microstructures and hardness. With increasing joint gap, the percent porosity area increased, reaching just over 1% of the fusion zone area at a gap width of 0·6 mm for the 3·2 and 5·1 mm thick sheets. The maximum underfill depth in the Ti-6Al-4V laser welds was about 5%or 7%of the sheet thickness for the 3·2 and5·2 mmthick materials, respectively, meeting the AWS D17-1 specification. The microindentation hardness was maximum in the fusion zone and sharply decreased through the heat affected zone until reaching the base metal value. © 2012 Crown in Right of Canada.
Keywords: Base metals; Bead geometry; Continuous Wave; Excellent corrosion resistances; Filler addition; Filler wire; Fusion zones; Gap widths; High specific strength; Joint gap; Laser welds; Microindentation hardness; ND : YAG lasers; Parent metal; Sheet thickness; Thick sheets; Ti alloys; Ti-6al-4v; Underfills; Aerospace industry; Aluminum; Corrosion resistance; Hardness; Laser beam welding; Mechanical properties; Microstructure; Titanium alloys; Welds; Neodymium lasers

Luminosities of barred and unbarred S0 galaxies - Van Den Bergh, S. (The Astrophysical Journal, 2012)
Lenticular galaxies with M B < -21.5 are almost exclusively unbarred, whereas both barred and unbarred objects occur at fainter luminosity levels. This effect is observed both for objects classified in blue light, and for those that were classified in the infrared. This result suggests that the most luminous (massive) S0 galaxies find it difficult to form bars. As a result, the mean luminosity of unbarred lenticular galaxies in both B and IR light is observed to be 0.4mag brighter than that of barred lenticulars. A small contribution to the observed luminosity difference that is found between SA0 and SB0 galaxies may also be due to the fact that there is an asymmetry between the effects of small classification errors on SA0 and SB0 galaxies. An elliptical (E) galaxy might be misclassified as a lenticular (S0) or an S0 as an E. However, an E will never be misclassified as an SB0, nor will an SB0 ever be called an E. This asymmetry is important because E galaxies are typically twice as luminous as S0 galaxies. The present results suggest that the evolution of luminous lenticular galaxies may be closely linked to that of elliptical galaxies, whereas fainter lenticulars might be more closely associated with ram-pressure stripped spiral galaxies. Finally, it is pointed out that fine details of the galaxy formation process might account for some of the differences between the classifications of the same galaxy by individual competent morphologists. © 2012. The American Astronomical Society. All rights reserved..

Continuous-wave operation of type-I GaSb-based narrow ridge waveguide lasers near 3254nm - Gupta, J.A.; Barrios, P.J.; Bezinger, A.; Waldron, P. (2012 Conference on Lasers and Electro-Optics, CLEO 2012, 2012)
Narrow ridge waveguide (5um) laser diodes were fabricated using type-I InGaAsSb/AlInGaAsSb quantum well active regions on GaSb. The devices operate in continuous-wave mode near 3254nm with a total light output of 7.4mW at 20°C (uncoated facets). © 2012 OSA.
Keywords: Active regions; Continuous wave modes; Continuous wave operation; InGaAsSb; Light output; Ridge waveguide lasers; Gallium alloys; Lasers; Ridge waveguides; Quantum well lasers

In vivo open-bore MRI reveals region- and sub-arc-specific lengthening of the unloaded human posterior cruciate ligament - King, A.J.; Deng, Q.; Tyson, R.; Sharp, J.C.; Matwiy, J.; Tomanek, B.; Dunn, J.F. (PLoS ONE, 2012)
Open-bore MRI scanners allow joint soft tissue to be imaged over a large, uninterrupted range of flexion. Using an open-bore scanner, 3D para-sagittal images of the posterior cruciate ligament (PCL) were collected from seven healthy subjects in unloaded, recumbent knee extension and flexion. PCL length was measured from one 2D MRI slice partition per flexion angle, per subject. The anterior surface of the PCL lengthened significantly between extension and flexion (p<0.001). Conversely, the posterior surface did not. Changes were not due to the PCL moving relative to the 2D slice partition; measurements made from 3D reconstructions, which compensated for PCL movement, did not differ significantly from measurements made from 2D slice partitions. In a second experiment, videos of knee flexion were made by imaging two subjects at several flexion angles. Videos allowed soft tissue tracking; examples are included. In a third experiment, unloaded knees of seven healthy, recumbent subjects were imaged at extension and at 40°, 70°, 90°, 100°, 110° and 120° flexion. The distance between PCL attachments increased between extension and 100°, and then decreased (p<0.001). The anterior surface of the PCL lengthened over the flexion angles measured (p<0.01). The posterior surface of the PCL lengthened between extension and 40° and then shortened (p<0.001). Both attachment separation and anterior surface length increased dramatically between extension and 40°, but varied less afterwards. Results indicate that PCL dynamics differ between terminal extension and active function sub-arcs. Also, attachment separation cannot predict the lengthening of all parts of the PCL, nor can lengthening of one part of the PCL predict the lengthening of another part. A potential connection between lengthening and loading is discussed. We conclude that low-field MRI can assess ligament lengthening during flexion, and that the dynamics of the PCL for any given region and sub-arc should be measured directly. © 2012 King et al.
Keywords: adult; article; controlled study; eye tracking; female; human; human experiment; human tissue; image analysis; image reconstruction; in vivo study; knee; knee extension; knee function; knee ligament; ligament lengthening; male; movement (physiology); musculoskeletal system parameters; normal human; nuclear magnetic resonance imaging; nuclear magnetic resonance scanner; open bore nuclear magnetic resonance imaging; partition coefficient; soft tissue; videorecording; Adult; Biomechanics; Female; Humans; Knee; Knee Joint; Magnetic Resonance Imaging; Posterior Cruciate Ligament; Video Recording

A model of ice friction for an inclined incising slider - Lozowski, E.P.; Szilder, K.; Maw, S. (Proceedings of the International Offshore and Polar Engineering Conference, 2012)
The FAST 2.0 model of ice friction was developed for a vertically oriented speed skate. The model is therefore left-right symmetrical about a vertical plane parallel to the sliding direction. It describes ice friction at sliding velocities sufficiently high to produce a lubricating layer of meltwater, which completely separates the ice and slider surfaces. Friction results from ploughing a groove in the ice and from the shear stress in the lubricating Couette flow. The model takes into account frictional melting, heat conduction into the ice and the lateral squeeze flow of the lubricating liquid. Here we present a new, numerical model, FAST 2.0i, which calculates ice friction for an inclined runner that is incising into the ice. Specifically, we consider an inclined speed skate blade and we use it to predict the variation of ice friction during a typical skating stroke. The model results compare favorably with in situ measurements. Copyright © 2012 by the International Society of Offshore and Polar Engineers (ISOPE).
Keywords: Couette flows; Frictional melting; Ice friction; In-situ measurement; Model results; Sliding direction; Sliding velocities; Squeeze flow; Theory; Vertical plane; Friction; Lubrication; Models; Physics; Recreational facilities; Ice

North American symposium on laser induced breakdown spectroscopy (NASLIBS): Introduction to feature issue - Singh, J.P.; Almirall, J.; Sabsabi, M.; Miziolek, A.W. (Applied Optics, 2012)
This feature issue highlights the topics of the 2011 North American Symposium on Laser Induced Breakdown Spectroscopy (NASLIBS). These include LIBS application to Security and Forensic, Biomedical and Environmental, Liquid Analysis and Fundamentals of LIBS, Instrumentation/Commercialization, Fusion with LIBS, and New Frontiers. © 2012 Optical Society of America.
Keywords: editorial; environmental monitoring; equipment design; instrumentation; laser; methodology; organization; spectroscopy; Congresses as Topic; Environmental Monitoring; Equipment Design; Lasers; Spectrum Analysis; North American; Optics; Molecular physics

Brain tumor surgery with 3-dimensional surface navigation - Mert, A.; Buehler, K.; Sutherland, G.R.; Tomanek, B.; Widhalm, G.; Kasprian, G.; Knosp, E.; Wolfsberger, S. (Neurosurgery, 2012)
BACKGROUND:: Precise lesion localization is necessary for neurosurgical procedures not only during the operative approach, but also during the preoperative planning phase. OBJECTIVE:: To evaluate the advantages of 3-dimensional (3-D) brain surface visualization over conventional 2-dimensional (2-D) magnetic resonance images for surgical planning and intraoperative guidance in brain tumor surgery. METHODS:: Preoperative 3-D brain surface visualization was performed with neurosurgical planning software in 77 cases (58 gliomas, 7 cavernomas, 6 meningiomas, and 6 metastasis). Direct intraoperative navigation on the 3-D brain surface was additionally performed in the last 20 cases with a neurosurgical navigation system. For brain surface reconstruction, patient-specific anatomy was obtained from MR imaging and brain volume was extracted with skull stripping or watershed algorithms, respectively. Three-dimensional visualization was performed by direct volume rendering in both systems. To assess the value of 3-D brain surface visualization for topographic lesion localization, a multiple-choice test was developed. To assess accuracy and reliability of 3-D brain surface visualization for intraoperative orientation, we topographically correlated superficial vessels and gyral anatomy on 3-D brain models with intraoperative images. RESULTS:: The rate of correct lesion localization with 3-D was significantly higher (P = .001, χ), while being significantly less time consuming (P < .001, χ) compared with 2-D images. Intraoperatively, visual correlation was found between the 3-D images, superficial vessels, and gyral anatomy. CONCLUSION:: The proposed method of 3-D brain surface visualization is fast, clinically reliable for preoperative anatomic lesion localization and patient-specific planning, and, together with navigation, improves intraoperative orientation in brain tumor surgery and is relatively independent of brain shift. © 2012 by the Congress of Neurological Surgeons.
Keywords: article; brain metastasis; brain size; brain tumor; cancer surgery; cavernoma; controlled study; glioma; human; intermethod comparison; major clinical study; meningioma; nuclear magnetic resonance imaging; preoperative evaluation; priority journal; three dimensional imaging; treatment planning; Algorithms; Brain Neoplasms; Humans; Imaging, Three-Dimensional; Neuronavigation; Software

Comparison of the computational NMR chemical shifts of choline with the experimental data - Alcorn, C.; Cuperlovic-Culf, M.; Ghandi, K. (Journal of Physics: Conference Series, 2012)
One of the main biological markers of the presence of cancer in living patients is an over-expression of total choline (tCho), which is the sum of free choline and its derivatives. 1H Magnetic Resonance Spectroscopy, or H-MRS, enables the quantification of tCho via its proton spectra, and thus has the potential to be a diagnostic tool for the presence of cancer and an accurate early indicator of the response of cancer to treatment. However, it remains difficult to quantify individual choline derivatives, since they share a large structural similarity ((CH 3) 3-N +-CH 2-CH 2-O-), of which the strongest signal detectable by MRS is that of the choline "head group": the three methyl groups bonded to the nitrogen. This work used ACENet, a high performance computing system, to attempt to model the NMR parameters of choline derivatives, with the focus of this report being free choline. Optimized structures were determined using Density Functional Theory and the B3LYP electron correlation functional. The Polarizable Continuum Model was used to evaluate solvent effects. The Gauge-Invariant Atomic Orbital method was found to be the superior method for calculating the NMR parameters of cholines. © IOP Publishing Ltd.
Keywords: Atomic orbital; Biological markers; Correlation functionals; Diagnostic tools; Experimental data; Head groups; High performance computing systems; Methyl group; NMR chemical shifts; Optimized structures; Over-expression; Polarizable continuum model; Proton spectra; Solvent effects; Structural similarity; Continuum mechanics; Functional groups; Magnetic resonance spectroscopy; Quantum chemistry; Diseases

Application of single-domain antibodies in tumor histochemistry - Maik, K.T.; MacKenzie, C.R. (Methods in Molecular Biology, 2012)
High avidity, pentameric, single-domain antibodies, oligomerized through the B subunit of verotoxin, are excellent immunohistochemical reagents. The resulting molecules are termed pentabodies. Here, we describe the immunostaining of tissue sections with ES1, a pentabody recognizing CEACAM6 which is overexpressed in several cancers. The advantages of pentabodies, compared to conventional antibody reagents, in immunohistochemical studies are highlighted. © 2012 Springer Science+Business Media, LLC.
Keywords: carcinoembryonic antigen related cell adhesion molecule 6; nanobody; pentabody ES1; unclassified drug; antibody specificity; antigen expression; article; cancer tissue; embedding; human; human tissue; immunohistochemistry; immunoreactivity; lung carcinoma; priority journal; procedures; sensitivity and specificity; tissue microarray; tissue section; cytochemistry; metabolism; methodology; neoplasm; pathology; Histocytochemistry; Humans; Neoplasms; Single-Domain Antibodies

Assessment of combustor working environments - Jiang, L.; Corber, A. (International Journal of Aerospace Engineering, 2012)
In order to assess the remaining life of gas turbine critical components, it is vital to accurately define the aerothermodynamic working environments and service histories. As a part of a major multidisciplinary collaboration program, a benchmark modeling on a practical gas turbine combustor is successfully carried out, and the two-phase, steady, turbulent, compressible, reacting flow fields at both cruise and takeoff are obtained. The results show the complicated flow features inside the combustor. The airflow over each flow element of the combustor can or liner is not evenly distributed, and considerable variations, ±25, around the average values, are observed. It is more important to note that the temperatures at the combustor can and cooling wiggle strips vary significantly, which can significantly affect fatigue life of engine critical components. The present study suggests that to develop an adequate aerothermodynamics tool, it is necessary to carry out a further systematic study, including validation of numerical results, simulations at typical engine operating conditions, and development of simple correlations between engine operating conditions and component working environments. As an ultimate goal, the cost and time of gas turbine engine fleet management must be significantly reduced. © 2012 Leiyong Jiang and Andrew Corber.
Keywords: Critical component; Engine operating conditions; Gas turbine combustor; Multi-disciplinary collaborations; Numerical results; Reacting flow field; Systematic study; Working environment; Engines; Fatigue of materials; Fleet operations; Flow fields; Gas turbines; Thermodynamics; Combustors

Semiautomated panning of naive camelidae libraries and selection of single-domain antibodies against peptide antigens - Kumaran, J.; MacKenzie, C.R.; Arbabi-Ghahroudi, M. (Methods in Molecular Biology, 2012)
With the identification of vast numbers of novel proteins through genomic and proteomic initiatives, the need for efficient processes to characterize and target them has increased. Antibodies are naturally designed molecules that can fulfill this need, and in vitro methodologies for isolating them from either immune or naïve sources have been extensively developed. However, access to pure protein antigens for screening purposes is a major hurdle due to the limitations associated with recombinant production of eukaryotic proteins. Consequently, rational peptide design based on proteomic methodologies such as protein modeling, secondary sequence prediction, and hydrophobicity/ hydrophilicity prediction, in combination with other bioinformatics data, is being explored as a viable solution to isolate specific antibodies against difficult antigens. Single-domain antibodies are becoming the ideal antibody format due to their structural advantages and ease of production compared to conventional antibodies and antibody fragments derived from conventional antibodies. For screening purposes, phage display technology is a well-established technique. With this technique, a repertoire of antibody fragments can be displayed on the surface of filamentous phages (f1, fd, M13) followed by screening against various antigenic targets. Furthermore, the technique can be expanded to a high-throughput scale using a magnetic-based, in-solution panning protocol which allows for the screening of multiple target antigens simultaneously. In this chapter, we describe a semiautomated panning method to screen a naïve Camelidae library against rationally designed peptide antigens, followed by preliminary characterization of isolated binders. © 2012 Springer Science+Business Media, LLC.
Keywords: antigen; nanobody; peptide antigen; unclassified drug; peptide; antibody library; antigen binding; antigen expression; antigen purification; article; Artiodactyla; biopanning; Camelidae; controlled study; epitope mapping; nonhuman; phage display; priority journal; protein protein interaction; screening test; semiautomated panning method; animal; antibody affinity; Artiodactyla; cell surface display; chemistry; genetics; immunology; isolation and purification; laboratory automation; methodology; peptide library; Animals; Antibody Affinity; Antigens; Automation, Laboratory; Camelids, New World; Cell Surface Display Techniques; Peptide Library; Peptides; Single-Domain Antibodies

VLBI for Gravity Probe B. I. overview - Shapiro, I.I.; Bartel, N.; Bietenholz, M.F.; Lebach, D.E.; Lestrade, J.-F.; Ransom, R.R.; Ratner, M.I. (Astrophysical Journal, Supplement Series, 2012)
We describe the NASA/Stanford gyroscope relativity mission, Gravity Probe B (GP-B), and provide an overview of the following series of six astrometric and astrophysical papers that report on our radio observations and analyses made in support of this mission. The main goal of this 8.5year program of differential very long baseline interferometry astrometry was to determine the proper motion of the guide star of the GP-B mission, the RS CVn binary IM Pegasi (IM Peg; HR 8703). This proper motion is determined with respect to compact, extragalactic reference sources. The results are -20.833 ± 0.090masyr -1 and -27.267 ± 0.095masyr -1 for, respectively, the right ascension and declination, in local Cartesian coordinates, of IM Peg's proper motion, and 10.370 ± 0.074mas (i.e., 96.43 ± 0.69pc) for its parallax (and distance). Each quoted uncertainty is meant to represent an 70% confidence interval that includes the estimated contribution from systematic error. These results are accurate enough not to discernibly degrade the GP-B estimates of its gyroscopes' relativistic precessions: the frame-dragging and geodetic effects. © 2012. The American Astronomical Society. All rights reserved..

SN-38 loaded polymeric micelles to enhance cancer therapy - Gu, Q.; Xing, J.Z.; Huang, M.; He, C.; Chen, J. (Nanotechnology, 2012)
7-Ethyl-10-hydroxycamptothecin (SN-38) loaded poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (Pluronic F-108) and poly(ethylene glycol)-block-poly("-caprolactone) (PEG-b-PCL) nanoparticles were successfully prepared by a modified film hydration method and characterized by scanning electric microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and dynamic light scattering (DLS). Satisfactory drug loading of 20.73 ± 0.66% and a high encapsulation efficiency of 83:83 ± 1:32% were achieved. The SN-38 nanoparticles (SN-38 NPs) can completely disperse into a phosphate buffered saline (PBS) medium to produce a clear aqueous suspension that remains stable for up to three days. Total drug releases were 67.91% and 91.09% after 24 h in a PBS or fetal bovine serum (FBS) medium. Half maximal inhibitory concentration (IC50) tests of SN-38 and SN-38 NPs on A549 lung cells produced results of 200.0±14.9 ng ml -1 and 80.0±4.6 ng ml -1, respectively. Similarly, IC50 tests of SN-38 and SN-38 NPs on MCF-7 breast cells yielded results of 16.0 ± 0.7 ng ml -1 and 8.0 ± 0.5 ng ml -1, respectively. These in vitro IC 50 studies show significant (p < 0.01) enhancement of the SN-38 NP drug efficiency in killing cancer cells in comparison to the free drug SN-38 control. All the materials used for this nanoformulation are approved by the US FDA, with the virtue of extremely low toxicity to normal cells. © 2012 IOP Publishing Ltd.
Keywords: Aqueous suspensions; Cancer cells; Cancer therapy; Caprolactone; Drug loading; Drug release; Encapsulation efficiency; Fetal bovine serum; Hydration method; In-vitro; Inhibitory concentration; Low toxicity; Lung cells; Modified film; Phosphate-buffered salines; Pluronics; Polymeric micelle; Propylene glycols; Transmission electron microscopy (TEM); Atomic force microscopy; Dynamic light scattering; Encapsulation; Loading; Nanoparticles; Transmission electron microscopy; Polyethylene glycols; antineoplastic agent; camptothecin; drug derivative; irinotecan; nanocapsule; apoptosis; article; cell survival; chemistry; diffusion; drug effect; experimental neoplasm; human; metabolism; micelle; tumor cell culture; Antineoplastic Agents, Phytogenic; Apoptosis; Camptothecin; Cell Survival; Diffusion; Humans; Micelles; Nanocapsules; Neoplasms, Experimental; Tumor Cells, Cultured

Testing large flats with computer generated holograms - Pariani, G.; Tresoldi, D.; Spanò, P.; Bianco, A. (Modern Technologies in Space- and Ground-Based Telescopes and Instrumentation II, 2012)
We describe the optical test of a large flat based on a spherical mirror and a dedicated CGH. The spherical mirror, which can be accurately manufactured and tested in absolute way, allows to obtain a quasi collimated light beam, and the hologram performs the residual wavefront correction. Alignment tools for the spherical mirror and the hologram itself are encoded in the CGH. Sensitivity to fabrication errors and alignment has been evaluated. Tests to verify the effectiveness of our approach are now under execution. © 2012 SPIE.
Keywords: CGH; Collimated light; Computer generated holograms; Fabrication errors; Flat mirrors; Optical test; Spherical mirror; Test; Wavefront correction; Alignment; Computer generated holography; Holograms; Interferometers; Mirrors; Optical telescopes; Spheres; Telescopes; Optical testing

A multi-point ultrasonic detection approach to fretting crack detection in an aircraft component - Wu, K.-T.; Sun, Z.; Jen, C.-K.; Blouin, A.; Mrad, N.; Bélanger, H. (Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2012, 2012)
A naturally cracked aircraft stabilizer former has been examined. By using surface shear horizontal diagnostic acoustic waves and a multi-point detection approach, a fretting crack, 0.2-inch long, 0.03-inch deep and at 0.06-inch to a rivet hole has been clearly identified. The proposed approach provides a simple way to interpret sensor output without imposing demanding transducer performance requirements. © 2012 SPIE.
Keywords: Aircraft components; Aircraft stabilizers; Detection approach; Performance requirements; Rivet hole; Sensor output; Shear horizontal waves; Surface shear; Ultrasonic detection; Acoustics; Aerospace engineering; Crack detection; Nondestructive examination; Optical engineering; Shear flow; Ultrasonic testing; Fretting corrosion

SPIRou @ CFHT: Data reduction software and simulation tools - Artigau, É.; Bouchy, F.; Delfosse, X.; Bonfils, X.; Donati, J.-F.; Figueira, P.; Thanjavur, K.; Lafrenière, D.; Doyon, R.; Surace, C.; Moutou, C.; Boisse, I.; et al. (SPIE - International Society for Optical Engineering. Proceedings, 2012)
SPIRou is a near-infrared, echelle spectropolarimeter/velocimeter under design for the 3.6m Canada-France-Hawaii Telescope (CFHT) on Mauna Kea, Hawaii. The unique scientific capabilities and technical design features are described in the accompanying papers at this conference. In this paper we focus on the data reduction software (DRS) and the data simulation tool. The SPIRou DRS builds upon the experience of the existing SOPHIE, HARPS and ESPADONS spectrographs; class-leaders instruments for high-precision RV measurements and spectropolarimetry. While SPIRou shares many characteristics with these instruments, moving to the near-infrared domain brings specific data-processing challenges: the presence of a large number of telluric absorption lines, strong emission sky lines, thermal background, science arrays with poorer cosmetics, etc. In order for the DRS to be fully functional for SPIRou's first light in 2015, we developed a data simulation tool that incorporates numerous instrumental and observational effects. We present an overview of the DRS and the simulation tool architectures. © 2012 SPIE.
Keywords: Absorption lines; Data simulation; Echelle; Exo-planets; High-precision; Instrumentation; Near Infrared; Near-infrared domains; Reduction software; Spectropolarimeters; Spectropolarimetry; Technical design; Thermal background; Astronomy; Data processing; Data reduction; Infrared devices; Instruments; Polarimeters; Spectroscopy; Tools