Laser cladding of high-performance CPM tool steels on hardened HI3 hot-work tool steel for automotive tooling applications - Chen, Jianyin; Xue, Lijue (Supplemental Proceedings: Materials Processing and Interfaces, Volume 1, 2012)
Keywords: laser cladding; CPM tool steels; H13 tool steel; tooling

Observation of mass-independent fractionation in MC-ICPMS and its implication for accurate isotope ratio measurements - Yang, L.; Mester, Z.; Sturgeon, R. E.; Meija, J. (Geophysical Research Abstracts, 2012)
Today, MC-ICPMS has become a powerful research tool for the high precision isotope ratio measurements with over five-hundred papers published annually in the past several years1-2. However, MC-ICPMS suffers approximately tenfold larger bias (up to 25 % for lithium3) in isotope amount ratio measurements as compared to thermal ionization mass spectrometry (TIMS). This bias needs to be properly corrected in order to obtain accurate isotope amount ratio measurements. The choice of the fractionation law to calibrate (correct) measured isotope ratios is crucial in isotope science. Over the last decades, the Russell law mass bias correction model (Eq. 1)4 which is applicable only for mass-dependent fractionation and assumes identical mass bias for both the calibrator and measurand elements, has become a standard curriculum in isotope ratio measurements. However, it has been reported that not only mass bias is different for different elements but also that the mass bias is different for different isotope pairs of a same element5-6. Mass-independent fractionation in MC-ICPMS has been observed for elements such as Nd, W and Cd5-7. Ri,j = ri,j(mi/mj)-f (1) Here Ri,j = n(iE)/n(jE), ri,j is the measured (uncorrected) isotope ratio and E is the element of interest, f is the fractionation function and mi,mj are the nuclide masses. In this talk, recent research results on MIF observed for Ge, Hg and Pb in MC-MCP in our group8 will be presented and its implication for Russell law mass bias correction for isotope amount ratio measurements will be presented and discussed.

Cerebral ischemia induced proteomic alterations: consequences for the synapse and organelles - Costain, Willard J.; Haqqani, Arsalan S.; Rasquinha, Ingrid; Giguere, Marie-Soleil; Slinn, Jacqueline (Advances in the Preclinical Study of Ischemic Stroke, 2012)

Addressing the challenge of inspecting buried nuclear piping in nuclear power plants - Angell, Peter; Wang, Sheng-Hui; Simon, Phil; Kleinfelder, Hank; Garrity, Kevin; Sisk, Elizabeth (ASME 2012 Pressure Vessels and Piping Conference: Volume 1, Codes and Standards, 2012)
Similar to many other industries, nuclear power plants (NPPs) have many kilometres of buried pipe that is not readily accessible for direct inspection. Given the nature of the systems, the nuclear industry experiences additional challenges as many services run in the same area, leading to what is described as a “spaghetti bowl” of piping. As a result, the traditional indirect, over the line, inspection practices developed for the oil and gas industry have not always been successfully applied at nuclear power plants. To address this issue, a collaborative Electric Power Research Institute/CANDU Owners Group (EPRI/COG) research project was established with Mears Group Inc. and Atomic Energy of Canada Limited (AECL) Nuclear Laboratories. In this program, initial testing of four methods was carried out at the Mears Group Inc, test site that had been modified with additional grounding systems to simulate a nuclear power plant. This was followed by testing of the same methods at the AECL Nuclear Laboratories Chalk River site. This paper will discuss the results of those studies and present some of the findings that were made that can help to overcome the challenges faced by Nuclear Power Plants.

Unsupervised data analysis methods used in qualitative and quantitative metabolomics and metabonomics - Cuperlovic-culf, Miroslava (Systemic Approaches in Bioinformatics and Computational Systems Biology, 2012)
Metabolomics or metababonomics is one of the major high throughput analysis methods that endeavors holistic measurement of metabolic profiles of biological systems. Data analysis approaches in metabolomics can broadly be divided into qualitative – analysis of spectral data and quantitative – analysis of individual metabolite concentrations. In this work, the author will demonstrate the benefits and limitations of different unsupervised analysis tools currently utilized in qualitative and quantitative metabolomics data analysis. Following a detailed literature review outlining different applications of unsupervised methods in metabolomics, the author shows examples of an application of the major previously utilized unsupervised analysis methods. The testing of these methods was performed using qualitative as well as corresponding quantitative metabolite data derived to represent a large set of 2,000 objects. Spectra of mixtures were obtained from different combinations of experimental NMR measurements of 13 prevalent metabolites at five different groups of concentrations representing different phenotypes. The analysis shows advantages and disadvantages of standard tools when applied specifically to metabolomics.

Abstract 2532: integrated therapeutic antibody development at the National Research Council of Canada - Jaramillo, Maria Luz; O'connor-McCourt, Maureen (Cancer Research, 2012)
Advances in genomics and antibody engineering have enabled the development of an innovative class of targeted therapies to provide new treatment options for diseases with significant unmet medical needs such as cancer. Therapeutic antibodies represent one of the fastest growing classes of medications with sales anticipated to exceed $30 billion globally by 2012. The NRC has built a chain of cutting edge technology platforms needed to discover, engineer and produce therapeutic monoclonal antibodies with the goal of partnering with industrial and academic centers to advance research and development of this important class of therapeutics. Target Identification- To establish and validate the technology platform, tumor targets for candidate therapeutic antibody production were identified using a combination of proteomics, transcriptomics and bioinformatic approaches. Out of these lists, approximately 40 tumor targets were selected (known therapeutic antibody targets were excluded), and over 2,000 antibodies of mouse and camelid origin were then generated against these targets. Antibody generation- Once identified, the recombinant target protein of interest can be produced using the NRC's high efficiency cell expression platforms in CHO or HEK293 cells and purified protein used for immunization or panning. For targets which are difficult to express or purify, the capabilities for direct immunization with plasmid DNA constructs provides another option. Clone selection is carried out by ELISA and typically 50 antibodies/target are identified for further characterization. Antibody characterization and validation- The affinities of the antibodies are determined by SPR biosensor analysis. Reverse phase protein arrays and Western blot analysis on protein mixes and cell lines allow the characterization of the specificity of the antibodies. Epitope mapping can be carried out so that representative antibodies from each epitope bin can be selected for further validation in appropriate cell-based assays (many of which are established at NRC) and animal models. Therapeutic antibody Optimization, Bioprocessing and Biomanufacturing- Therapeutic antibodies selected for development can be further optimized using antibody engineering technologies to humanize them and/or modify their glycosylation patterns to improve their effector function, pharmacokinetics, solubility and stability as well as reduce their immunogenicity. The NRC platform for large scale protein production has the capacity to manufacture up to 13.5 g of commercial grade antibody using serum free, low endotoxin media in a cGMP certified CHO cell line which is ready for transfer to CMOs or other industrial partners.

Application of metabolomics in drug discovery, development and theranostics - Cuperlovic-Culf, Miroslava; S. Culf, Adrian; Jr Morin, Pier; Touaibia, Mohamed (Current Metabolomics, 2012)
High throughput analysis of metabolites combined with systems biology is opening new opportunities in medical research and clinical applications. Investigation of metabolic phenotype and metabolic requirements of a disease opens new avenues for treatments. Analysis of metabolic changes in patients and in disease models following treatments provides new methods for investigation of therapeutic response. Combined examination of disease metabolic characteristics and treatment response provides markers for personalization of therapies. Metabolomics finds itself at an increasingly important junction in all of these applications. In this review, we will explore the advantages of combining metabolomics with systems biology to optimize the drug discovery process via in-depth analysis of biological systems and novel metabolism- targeted therapeutics. Assessment of efficacy and specificity of drugs that directly or indirectly target metabolism through analyses of metabolic changes will also be presented. Finally, we will highlight examples of metabolic biomarkers explored as promising theranostics and theranostic imaging tools aimed at therapy optimization and combined therapy and diagnostics. The focus of this review will be directed towards cancer, however, the overarching ideas as well as experimental and analysis approaches are easily transferable to other applications. In cancer research, metabolism is once again raising interest due to a better appreciation of the significance of altered metabolic phenotype in cancer development and progression. Investigation of metabolic changes in cancer following drug applications and identification of clinically relevant metabolic markers for particular cancer subtypes are becoming increasingly appreciated in treatment development and will be explored in this review.
Keywords: bioreactors; drug discovery; drug testing; fluxomics; metabolomics; theragnostics imaging; theragnostics treatment planning; systems biology

Oilseed crop productivity under salt stress - Nayidu, Naghabushana; Bollina, Venkatesh; Kagale, Sateesh (Ecophysiology and Responses of Plants under Salt Stress, 2012)
Agricultural production around the world, especially where it mainly depends on irrigation, is confronted with serious challenges of coping with soil salinity conditions as well as saline irrigation water. Soil salinity is increasing regularly throughout the world and has become a great menace for agriculture. About 800 million hectares of the world land are salt-affected, of which 397 million hectares are saline and 434 million hectares sodic. Soil salinity adversely affects crop growth and productivity. In oilseed crops, salt stress affects both vegetative and reproductive growth stages by reducing growth, delaying the onset of flowering, reducing the quantum of reproductive structures and delaying the maturation processes, ultimately leading to diminished crop yield. Additionally, it affects production of several enzymes leading to the reduction of glycerides and modification of the fatty acid profile, important quality determinants of seed oil. Thus, salt stress has become a major factor affecting oilseed production worldwide. Here, we have reviewed the effects of salt stress on growth and productivity of oilseed crops. Additionally, different strategies employed by crop plants against salt stress as well as research reports describing genetic and transgenic approaches designed for improving plants ability to overcome salt stress are discussed.
Keywords: Plant breeding; Plant genetics; Plant physiology

Advances in microspore culture technology: a biotechnological tool for the improvement of medicinal plants - Ferrie, Alison M. R. (Biotechnology for Medicinal Plants, 2012)
Doubled haploidy techniques are well established for some species and are routinely used for practical application and basic research. Haploid/doubled haploid plants can be produced via a number of ways although the in vitro methods of androgenesis (culture of the male gametophyte) or gynogenesis (culture of the female gametophyte) are the most common. For medicinal plants, very little genetic improvement has been undertaken when compared to major crop species. However, callus, embryos, and doubled haploid plants have been produced in several medicinal species using a range of media formulations and culture conditions. This chapter focuses on doubled haploid production from the male gametophyte and the factors influencing this response.Doubled haploidy methodology would be beneficial for medicinal species as uniform, homozygous, true breeding lines would be available for growers. Uniformity in plants and in the active ingredient is very important for regulatory standards and for those conducting clinical trials.
Keywords: Plant Physiology; Cell culture; Biotechnology; Pharmacology; Toxicology

Effect of nanoparticles on electrolytes and electrode/electrolyte interface - Salem, Nuha; Abu-Lebdeh, Yaser (Nanotechnology for Lithium-Ion Batteries, 2012)
The addition of nano-sized inorganic fillers such as SiO2 to solid and liquid electrolytes to enhance their electrochemical and physical properties has been recently the focus of great deal of research. In this chapter, we review the work done in this area where various types of nanoparticles including ceramics and clay were used as additives to electrolytes commonly used in lithium-ion batteries research such as polymer electrolytes (gel and solid form), ionic and organic liquid electrolytes and plastic crystals.

Combination of High Spatial Resolution LII and LOSA measurements for determination of soot volume fraction and PAH concentration in laminar diffusion flames - Leschowski, M.; Thomson, K.; Clavel, D.; Snelling, D.; Schulz, C.; Smallwood, G. (Laser-induced Incandescence 2012, 2012)
Presented at poster session
Présentée à la séance de présentation par affiches, session

Carbon-supported iridium catalyst for reduction of chlorate ions with hydrogen in concentrated solutions of sodium chloride - Kuznetsova, Lidia I.; Kuznetsova, Nina I.; Koscheev, Sergei V.; Zaikovski, Vladimir I.; Lisitsyn, Alexander S.; Kaprielova, Ksenia M.; Kirillova, Natalia V.; Twardowski, Zbigniev (Applied Catalysis A: General, 2012)
In production of chlorine by electrolysis of NaCl, chlorate is formed as by-product and must be removed. The back conversion of ClO3− to Cl− via catalytic reduction with H2 on Ir catalyst in NaCl brine has been studied. The catalysts contained 0.5–5 wt.% of Ir and were prepared via impregnation of mesoporous carbon support (Sibunit™) with solutions of IrCl3·xHCl·yH2O or H2IrCl6 and reduction in flowing H2 at 400 or 500 °C. The Ir/C samples have been characterized with CO adsorption, XPS and HRTEM. The rate of ClO3− reduction in concentrated solutions of NaCl was found dependent on pH (in the range 2–6), content of Ir in the catalyst, dispersion and distribution of Ir on the support. The best properties have been shown by 5%Ir/C catalyst which was prepared with H2IrCl6 as the metal precursor and contained small Ir particles (∼1.5 nm in diameter) located inside the cavities of carbon globules. Stable catalytic performance in multiple successive runs has been achieved.

Study of true stress-strain curve after necking for application in ductile fracture criteria in tube hydroforming of aerospace material - Saboori, M.; Champliaud, H.; Gholipour, J.; Gakwaya, A.; Savoie, J.; Wanjara, P. (Key Engineering Materials, 2012)
The increased demand for weight reduction and manufacture of complex shapes with tube hydroforming (THF) requires more accurate material models to achieve highly reliable results from simulations. Conventional flow behaviours of materials implemented in commercial finite element (FE) software are not capable of describing accurately the material behaviour after localization. Utilization of the stress-strain data after necking can improve the quality of the FE analysis by employing realistic data for extrapolating the stress-strain curve. In this paper, the objective was to develop a simple tool that can determine the true stress-strain curve after necking in order to predict the material behaviour of aerospace alloys such as stainless steel 321 (SS321). Standard uniaxial tensile tests (ASME E8M-04) were performed to determine the true stress-strain before necking. A weighted-average method and a new hardening equation were proposed to extend the curve after necking.
Keywords: Work hardening law; Material behaviour; Weighted average method; Diffuse necking

Increasing the hydroformability of stainless steel 321 by multistep processing - Anderson, Melissa; Bocher, Philippe; Gholipour, Javad; Jahazi, Mohammad; Savoie, Jean; Wanjara, Priti (Steel Research Journal, 2012)
The application of the tube hydroforming process for the manufacture of aerospace components is relatively new and challenging due to the limited formability of high strength alloys used for aerospace applications. A multistep forming process, including intermediate heat treatment steps, has been proposed as a viable solution for increasing the hydroformability of these alloys. Interrupted free expansion tests were used in this study to emulate the multistep forming. Initially, free expansion tests were performed up to the burst point to determine the maximum pressure. An automated 3D deformation measurement system, ARAMIS®, was used to measure the strain distribution along the tube length as well as to measure the bulge height (expansion) as a function of time. Based on the strain distribution results obtained from ARAMIS®, a pause pressure corresponding to about 80% of the burst or maximum pressure was selected as the interruption point of the free expansion test in order to apply a softening heat treatment to restore the formability of the material. After this free expansion and softening cycle, the tube was then hydroformed up to the burst point.The results indicated that the inclusion of an intermediate heat treatment before the second forming step increased the expansion from 9.5 mm to 12 mm, a 26% increase. Interestingly, in addition to the higher expansion, the pressure required to reach a specific level of expansion was reduced by half due to the softening effect of the intermediate heat treatment and thinning of the tubes from the first forming step.
Keywords: Stainless steel; multistep forming; free expansion tests; heat treatment; tube hydroforming

The GALEX Ultraviolet Virgo Cluster Survey (GUViCS) II. Constraints on star formation in ram-pressure stripped gas - Bossier, S.; Boselli, A.; Duc, P.-A.; Cortese, L.; van Driel, W.; Heinis, S.; Voyer, E.; Cucciati, O.; Ferrarese, L.; Côté, P.; Cuillandre, J.-C.; Gwyn, S.D.J.; et al. (Astronomy and Astrophysics, 2012)
Context. Several galaxies in the Virgo cluster are known to have large H i gas tails related to a recent ram-pressure stripping event. The Virgo cluster has been extensively observed at 1539 Å in the far-ultraviolet for the GALEX Ultraviolet Virgo Cluster Survey (GUViCS), and in the optical for the Next Generation Virgo Survey (NGVS), allowing a study of the stellar emission potentially associated with the gas tails of 8 cluster members. On the theoretical side, models of ram-pressure stripping events have started to include the physics of star formation. Aims. We aim to provide quantitative constraints on the amount of star formation taking place in the ram-pressure stripped gas, mainly on the basis of the far-UV emission found in the GUViCS images in relation with the gas content of the tails. Methods. We have performed three comparisons of the young stars emission with the gas column density: visual, pixel-by-pixel, and global. We have compared our results to other observational and theoretical studies. Results. We find that the level of star formation taking place in the gas stripped from galaxies by ram-pressure is low with respect to the available amount of gas. Star formation is lower by at least a factor 10 compared to the predictions of the Schmidt Law as determined in regular spiral galaxy disks. It is also lower than measured in dwarfs galaxies and the outer regions of spirals, and than predicted by some numerical simulations. We provide constraints on the star formation efficiency in the ram-pressure stripped gas tails, and compare these with current models.
Keywords: galaxies; Virgo; star formation; astronomy

Nanofabrication: techniques and principles - Stepanova, Maria; Dew, Steven (Springer International Publishing, 2012)
Intended to update scientists and engineers on the current state of the art in a variety of key techniques used extensively in the fabrication of structures at the nanoscale. The present work covers the essential technologies for creating sub 25 nm features lithographically, depositing layers with nanometer control, and etching patterns and structures at the nanoscale. A distinguishing feature of this book is a focus not on extension of microelectronics fabrication, but rather on techniques applicable for building NEMS, biosensors, nanomaterials, photonic crystals, and other novel devices and structures that will revolutionize society in the coming years.

Preface - Stepanova, Maria; Dew, Steven (Nanofabrication: Techniques and Principles, 2012)

Rescue of beta-amyloid–induced alterations in cerebrovascular protein expression by pioglitazone in APP mice: Link to functional recovery in the cerebrovasculature - Badhwar, Aman; Brown, R.; Delaney, Christie; Stanimirovic, D.B.; Haqqani, Arsalan; Hamel, Edith (Alzheimer's and Dementia, 2012)
Cerebrovascular dysfunction appears prior to Aβ-plaque deposition and measurable mnemonic impairment in Alzheimer's disease (AD) patients and amyloid precursor protein (APP)-expressing transgenic mice. The soluble, highly toxic Aβ-fragment generated from the amyloidogenic processing of APP is likely the primary instigator of chronic cerebrovascular insufficiency in APP mice. We recently demonstrated that the PPAR-gamma agonist, pioglitazone, is a potent drug for reversing cerebrovascular impairment at all stages of Aβ-induced pathology in APP mice. Our aims are to (a) characterize the effect of Aβ-overproduction on the cerebrovascular proteome of APP mice; (b) determine the extent to which pioglitazone rescues the Aβ-altered cerebrovascular proteome; and (c) determine the link between protein expression rescue by pioglitazone and functional recovery in the cerebrovasculature.
Keywords: Alzheimer's disease; amyloid precursor protein mice; pioglitazone; cerebrovascular impairment

Quantitative proteomics of Alzheimer's-like cerebral vasculature in TGF-ß1 overexpressing mice and its perturbation by pioglitazone - Badwar, Aman; Stanimirovic, D.B.; Haqqani, Arsalan; Hamel, Edith (Alzheimer's and Dementia, 2012)
Elevation of transforming growth factor-beta 1 (TGFβ1), a key extracellular matrix regulator, has been documented in the brain and cerebral vasculature of Alzheimer's disease (AD) patients. Transgenic mice overexpressing TGFβ1 in the brain (TGF mice) develop AD-like vascular structural changes, impaired vasomotricity, and compromised neurovascular coupling. We have demonstrated that cerebrovascular dysfunction in both aged and young TGF mice is normalized by the peroxisome proliferator-activated receptor-γ agonist pioglitazone. Our aims are to (a) characterize the cerebrovascular proteome of TGF mice and its perturbation by pioglitazone using label-free mass spectrometry-based quantitative proteomics, and (b) identify proteins that orchestrate pioglitazone-mediated recovery of cerebrovascular function.
Keywords: TGF-ß1; Alzheimer's disease; cerebral vasculature; brain

Imaging blood–brain barrier dysfunction in animal disease models - Wunder, Andreas; Schoknecht, Karl; Stanimirovic, Danica B.; Prager, Ofer; Chassidim, Yoash (Epilepsia, 2012)
The blood–brain barrier (BBB) is a highly complex structure, which separates the extracellular fluid of the central nervous system (CNS) from the blood of CNS vessels. A wide range of neurologic conditions, including stroke, epilepsy, Alzheimer’s disease, and brain tumors, are associated with perturbations of the BBB that contribute to their pathology. The common consequence of a BBB dysfunction is increased permeability, leading to extravasation of plasma constituents and vasogenic brain edema. The BBB impairment can persist for long periods, being involved in secondary inflammation and neuronal dysfunction, thus contributing to disease pathogenesis. Therefore, reliable imaging of the BBB impairment is of major importance in both clinical management of brain diseases and in experimental research. From landmark studies by Ehrlich and Goldman, the use of dyes (probes) has played a critical role in understanding BBB functions. In recent years methodologic advances in morphologic and functional brain imaging have provided insight into cellular and molecular interactions underlying BBB dysfunction in animal disease models. These imaging techniques, which range from in situ staining to noninvasive in vivo imaging, have different spatial resolution, sensitivity, and capacity for quantitative and kinetic measures of the BBB impairment. Despite significant advances, the translation of these techniques into clinical applications remains slow. This review outlines key recent advances in imaging techniques that have contributed to the understanding of BBB dysfunction in disease and discusses major obstacles and opportunities to advance these techniques into the clinical realm.
Keywords: Blood–brain barrier; Fluorescence imaging; Magnetic resonance imaging; Nuclear imaging

Impact of initial surface parameters on the final quality of laser micro-polished surfaces - Chow, Michael; Bordatchev, Evgueni V.; Knopf, George K. (Proceedings of SPIE 8248, 2012)
Laser micro-polishing (LμP) is a new laser-based microfabrication technology for improving surface quality during a finishing operation and for producing parts and surfaces with near-optical surface quality. The LμP process uses low power laser energy to melt a thin layer of material on the previously machined surface. The polishing effect is achieved as the molten material in the laser-material interaction zone flows from the elevated regions to the local minimum due to surface tension. This flow of molten material then forms a thin ultra-smooth layer on the top surface. The LμP is a complex thermo-dynamic process where the melting, flow and redistribution of molten material is significantly influenced by a variety of process parameters related to the laser, the travel motions and the material. The goal of this study is to analyze the impact of initial surface parameters on the final surface quality. Ball-end micromilling was used for preparing initial surface of samples from H13 tool steel that were polished using a Q-switched Nd:YAG laser. The height and width of micromilled scallops (waviness) were identified as dominant parameter affecting the quality of the LμPed surface. By adjusting process parameters, the Ra value of a surface, having a waviness period of 33 μm and a peak-to-valley value of 5.9 μm, was reduced from 499 nm to 301 nm, improving the final surface quality by 39.7%.

Supplement to the NBC 2010 : Intent Statements - Canadian Commission on Building and Fire Codes, National Research Council of Canada (2012)
Keywords: Codes and guides

Characterization of triangulation-based 3D imaging systems using certified artifacts - Beraldin, Jean-Angelo; Carrier, Benjamin; MacKinnon, David; Cournoyer, Luc (NCSL International Measure: The Journal of Measurement Science, 2012)
A set of test procedures and certified artifacts to characterize the capability of short-range triangulation-based threedimensional (3D) imaging systems are presented. The approach consists of scanning metallic and coated glass certified artifacts in which the uncertainties in the associated characteristic reference values are smaller than the measurement uncertainties produced by the system under test (SUT). The artifacts were grouped on the same plate for portability. To define a set of test procedures that is practical, simple to perform and easy to understand, we utilized a terminology that is well-known in the manufacturing field, i.e., geometric dimensioning and tolerancing (GD&T). The National Research Council Portable Characterization Target (NRC-PCT) is specifically designed for the characterization of systems with depths of field from 50 mm to 500 mm. Tests were performed to validate the capability of the NRC-PCT. This paper presents these results, along with some basic information on 3D imaging systems.

Predicting the fire-resistance of cross-laminated timber assemblies - Craft, S.T.; Desjardins, R.; Bénichou, Noureddine (2012)
This research aims to address two primary objectives which will support the North American adoption of CLT (cross-laminated timber). First, a generic calculation method for determining the fire-resistance of CLT assemblies is needed to enable producers to manufacture a number of different configurations of panels without the need to run a large number of full-scale fire tests. Second, the CLT assemblies chosen for testing have been identified as the most likely configurations to be used thereby providing test data to support the claims of fire-resistance to help satisfy the authority having jurisdiction. (...)
Keywords: fire resistance; cross-laminated timber assemblies

The impact of post-fire earthquakes on FRP-strengthened concrete structural systems - Bénichou, Noureddine; Mostafaei, Hossein; Green, Mark; Bisby, Luke; Kodur, Venkatesh (6th International Conference on Advanced Materials in Bridges and Structures 2012 (ACMBS-VI 2012), 2012)
This paper presents the results of a research project to study the structural fire resistance of FRP-strengthened concrete members under fire exposure. The items presented in this paper are: 1) Some of the results of an experimental program, conducted at NRC, on FRP-strengthened RC columns exposed to standard fires; 2) The numerical fire simulation models that were developed to predict the heat transfer behavior of FRP-strengthened RC columns during fire exposure; 3) the recommendations for design guidance for FRP-strengthened RC structures in fire. The paper also presents the impact of lateral loading on structural columns after fire to assess the effectiveness of structural resistance of fire-damaged FRP-strengthened building elements in case of an earthquake.
Keywords: FRP-strengthened concrete; fire resistance; heat transfer; structural resistance

Performance in fire of fibre reinforced polymer strengthened concrete beams and columns: recent recent and implications for design - Green, Mark F.; Hollingshead, Kevin; Benichou, Noureddine (Proceedings of the 7th International Conference on Structures in Fire, 2012)
This paper considers the fire performance of concrete beams and columns that have been strengthened with fibre reinforced polymers (FRPs). Results from four recent full-scale tests are presented. A newly developed type of insultation was employed and the thickness of the insulation (15 to 20 mm) was approximately half that provided in earlier tests. All of the members survived four hours of fire exposure. A conceptual model for design is also presented. Further research needed to fully develop the conceptual model to a more practical design tool is outlined.
Keywords: fire; fibre reinforced polymers; concrete; strengthening; repair; rehabilitation

Performance of displacement ventilation in Canadian schools: field studies - Ouazia, B.; MacDonald, I.A.; Tardif, M.; Thompson, A.; Booth, D.G. (2012)
Displacement ventilation systems take a fundamentally different approach to space conditioning than the systems found in the majority of commercial buildings, which currently use a fully mixed and dilution approach to ventilation. Displacement ventilation (DV) is an alternate air distribution method for commercial spaces, in particular schools. 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. A series of field studies in existing Canadian schools were carried out during the heating season over the last three years. This paper presents results from field studies conducted in schools designed for displacement ventilation with a perimeter radiant heating system. We measured several aspects of the performance of a DV systems installed in schools located in different parts of the country. The results show that the measured contaminant removal effectiveness was higher than that provided in previous studies for heating mode. In addition, key predictors of thermal comfort are also generally within limits set by ASHRAE standards. The results of these field studies provide some evidence of thermal comfort and IAQ-related benefits of DV in cold climate. However, before general conclusions are drawn, the benefits need to be confirmed in other studies.

Air change effectiveness with displacement ventilation in heating season - MacDonald, Iain; Ouazia, B.; Thompson, A.J.L.; Booth, D. (2012)

Historical time-domain: data archives, processing, and distribution - Grindlay, Jonathan E.; Griffin, R. Elizabeth (New horizons in time-domain astronomy: proceedings of the 285th Symposium of the International Astronomical Union held in Oxford, United Kingdom September 19 - 23, 2011, 2012)
The workshop on Historical Time-Domain Astronomy (TDA) was attended by a near-capacity gathering of ~30 people. From information provided in turn by those present, an up-to-date overview was created of available plate archives, progress in their digitization, the extent of actual processing of those data, and plans for data distribution. Several recommendations were made for prioritising the processing and distribution of historical TDA data.

Distributed H∞ control of dynamically coupled segmented telescope mirrors: design and simulation - Ulutas, Baris; Kerley, Daniel; Dunn, Jennifer; Suleman, Afzal; Park, Edward J. (Mechatronics, 2012)
Next generation telescopes are to employ segmented mirrors to realize extremely large primary mirror surfaces. For example, one of the current next generation large telescope projects, the Thirty Meter Telescope (TMT), will employ a 30 m primary mirror with 492 segments. With the high degree of segmentation, control of these segments against external disturbances to maintain the parabolic mirror shape becomes a challenging task. In this paper, a preliminary study of H ∞ control of the segmented primary mirror is presented. Both spatially-invariant distributed and centralized H ∞ controllers are designed for a proof-of-concept 37-segment system model. In our proposed mirror design, the segments are dynamically coupled through a uniform support structure, which is modeled using the finite element method. In addition, the segments have the coupled control objective of maintaining the overall mirror shape to allow the highest possible image resolution. A spatially-invariant distributed model is obtained by using a finite element model of the 7-segment system. The resulting model is then used to synthesize a spatially-invariant distributed controller, and is expanded to obtain the 37-segment system by interconnecting the distributed model in a honeycomb-like pattern. The simulation results of the distributed controller is presented and compared with the results from the centralized H ∞ controller applied to the 37-segment model. It is shown that both centralized and spatially-invariant distributed controllers satisfy the imaging performance requirements. © 2011 Elsevier Ltd. All rights reserved.
Keywords: Control objectives; Design and simulation; Distributed control; Distributed controller; Distributed models; External disturbances; Finite element models; Imaging performance; Large telescopes; Mirror design; Mirror shape; Parabolic mirrors; Segmented primary mirrors; Segmented telescope; Spatially-invariant; Support structures; System models; Thirty Meter Telescope; Distributed parameter control systems; Finite element method; Image resolution; Optical telescopes

Preface - Lockwood, D. J.; Mascher, P. (ECS Meeting Abstracts: 221st ECS Meeting, 2012)

Preface - Taylor, E. J.; Bock, C.; Inman, M.; Malek, K. (ECS Meeting Abstracts: Honolulu PRiME 2012, 2012)

Preface - Bock, C.; Leddy, J. (ECS Meeting Abstracts: 220th ECS Meeting, 2012)

Characterization of individual multifunctional nanoobjects with restricted geometry - Harnagea, C.; Azodi, M.; Nechache, R.; Cojocaru, C.-V.; Buscaglia, V.; Buscaglia, M. T.; Nanni, P.; Rosei, F.; Pignolet, A. (Phase Transitions, 2012)
Anisotropic nanostructures such as nanowires (NWs)/nanotubes and nanometer-sized islands are the subject of intense research efforts due to several interesting phenomena observed to occur in confined geometries with a high aspect ratio and/or reduced size. Understanding and controlling the mechanical and electromechanical behaviors of these nanostructures are crucial for the practical implementation of such building blocks as active or passive components in nanodevices. Recent progresses toward the characterization of individual one-dimensional (NWs and nanotubes) and two-dimensional (islands) functional nanoscale objects of piezoelectric and ferroelectric (BaTiO3, Bi 4Ti3O12 (BiT), and NaNbO3) and multiferroics (BiFeO3 and Bi2FeCrO6 (BFCO)) are presented. These nanoobjects have been characterized using scanning probe microscopy-based techniques, combined with various modulation schemes for enhanced sensing capabilities. The most remarkable results include: ferroelectricity of NaNbO3/Nb2O5 nanotube heterostructures, negative piezoelectric coefficient in highly anisotropic BiT mesoscopic rods, and preservation of the multiferroic character of epitaxial BFCO nanoislands. © 2013 Copyright Taylor and Francis Group, LLC.
Keywords: Anisotropic nanostructures; Bismuth ferrites; Bismuth titanate; Electromechanical behavior; Ferroelectric nanostructures; Piezoelectric coefficient; Piezoresponse force microscopy; Restricted geometries; Anisotropy; Aspect ratio; Barium titanate; Bismuth; Ferroelectricity; Nanowires; Niobium oxide; Piezoelectricity; Scanning probe microscopy; Nanotubes

HMDB 3.0-The Human Metabolome Database in 2013 - Wishart, David S.; Jewison, Timothy; Guo, An Chi; Wilson, Michael; Knox, Craig; Liu, Yifeng; Djoumbou, Yannick; Mandal, Rupasri; Aziat, Farid; Dong, Edison; Bouatra, Souhaila; Sinelnikov, Igor; et al. (Nucleic Acids Research, 2012)
The Human Metabolome Database (HMDB) (www. hmdb.ca) is a resource dedicated to providing scientists with the most current and comprehensive coverage of the human metabolome. Since its first release in 2007, the HMDB has been used to facilitate research for nearly 1000 published studies in metabolomics, clinical biochemistry and systems biology. The most recent release of HMDB (version 3.0) has been significantly expanded and enhanced over the 2009 release (version 2.0). In particular, the number of annotated metabolite entries has grown from 6500 to more than 40000 (a 600% increase). This enormous expansion is a result of the inclusion of both 'detected' metabolites (those with measured concentrations or experimental confirmation of their existence) and 'expected' metabolites (those for which biochemical pathways are known or human intake/exposure is frequent but the compound has yet to be detected in the body). The latest release also has greatly increased the number of metabolites with biofluid or tissue concentration data, the number of compounds with reference spectra and the number of data fields per entry. In addition to this expansion in data quantity, new database visualization tools and new data content have been added or enhanced. These include better spectral viewing tools, more powerful chemical substructure searches, an improved chemical taxonomy and better, more interactive pathway maps. This article describes these enhancements to the HMDB, which was previously featured in the 2009 NAR Database Issue. (Note to referees, HMDB 3.0 will go live on 18 September 2012.)

ECMDB: The E. coli Metabolome Database - Guo, An Chi; Jewison, Timothy; Wilson, Michael; Liu, Yifeng; Knox, Craig; Djoumbou, Yannick; Lo, Patrick; Mandal, Rupasri; Krishnamurthy, Ram; Wishart, David S. (Nucleic Acids Research, 2012)
The Escherichia coli Metabolome Database (ECMDB, http://www.ecmdb.ca) is a comprehensively annotated metabolomic database containing detailed information about the metabolome of E. coli (K-12). Modelled closely on the Human and Yeast Metabolome Databases, the ECMDB contains >2600 metabolites with links to ∼1500 different genes and proteins, including enzymes and transporters. The information in the ECMDB has been collected from dozens of textbooks, journal articles and electronic databases. Each metabolite entry in the ECMDB contains an average of 75 separate data fields, including comprehensive compound descriptions, names and synonyms, chemical taxonomy, compound structural and physicochemical data, bacterial growth conditions and substrates, reactions, pathway information, enzyme data, gene/protein sequence data and numerous hyperlinks to images, references and other public databases. The ECMDB also includes an extensive collection of intracellular metabolite concentration data compiled from our own work as well as other published metabolomic studies. This information is further supplemented with thousands of fully assigned reference nuclear magnetic resonance and mass spectrometry spectra obtained from pure E. coli metabolites that we (and others) have collected. Extensive searching, relational querying and data browsing tools are also provided that support text, chemical structure, spectral, molecular weight and gene/protein sequence queries. Because of E. coli's importance as a model organism for biologists and as a biofactory for industry, we believe this kind of database could have considerable appeal not only to metabolomics researchers but also to molecular biologists, systems biologists and individuals in the biotechnology industry. © The Author(s) 2012.
Keywords: bacterial enzyme; bacterial protein; amino acid sequence; bacterial gene; bacterial growth; bacterial metabolism; bacterial strain; bioinformatics; carbon nuclear magnetic resonance; chemical structure; Escherichia coli; factual database; gene sequence; mass spectrometry; metabolite; metabolome; molecular weight; proton nuclear magnetic resonance; Databases, Genetic; Escherichia coli K12; Escherichia coli Proteins

Unearthing foundations of a cosmic cathedral: searching the stars for M33's halo - Cockcroft, Robert; McConnachie, Alan W.; Harris, William E.; Ibata, Rodrigo; Irwin, Mike J.; Ferguson, Annette M. N.; Fardal, Mark A.; Babul, Arif; Chapman, Scott C.; Lewis, Geraint F.; Martin, Nicolas F.; Puzia, Thomas H. (Monthly Notices of the Royal Astronomical Society, 2012)
We use data from the Pan-Andromeda Archaeological Survey to search for evidence of an extended halo component belonging to M33 (the Triangulum Galaxy).We identify a population of red giant branch (RGB) stars at large radii fromM33's disc whose connection to the recently discovered extended 'disc substructure' is ambiguous, and which may represent a 'bona fide' halo component. After first correcting for contamination from the Milky Way foreground population and misidentified background galaxies, we average the radial density of RGB candidate stars over circular annuli centred on the galaxy and away from the disc substructure. We find evidence of a low-luminosity, centrally concentrated component that is everywhere in our data fainter than μV ~ 33 mag arcsec-2. The scalelength of this feature is not well constrained by our data, but it appears to be of the order of rexp ~20 kpc; there isweak evidence to suggest that it is not azimuthally symmetric. Inspection of the overall colour-magnitude diagram for this region that specifically clips out the disc substructure reveals that this residual RGB population is consistent with an old population with a photometric metallicity of around [Fe/H] ~ -2 dex, but some residual contamination from the disc substructure appears to remain. We discuss the likelihood that our findings represent a bona fide halo in M33, rather than extended emission from the disc substructure. We interpret our findings in terms of an upper limit to M33's halo that is a fewper cent of its total luminosity, although its actual luminosity is likely much less. © 2012 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Generalised canonical-isokinetic ensemble: speeding up multiscale molecular dynamics and coupling with 3D molecular theory of solvation - Omelyan, Igor; Kovalenko, Andriy (Molecular Simulation, 2012)
We have proposed a new canonical-isokinetic ensemble for efficient sampling of conformational space in molecular dynamics (MD) simulations which leads to the optimised isokinetic Nosé-Hoover (OIN) chain algorithm for atomic and molecular systems. We applied OIN to multiple time step (MTS) MD simulations of the rigid and flexible models of water to demonstrate its advantage over the standard canonical, isokinetic and canonical-isokinetic ensembles. With the stabilising effect of OIN thermostatting in MTS-MD, gigantic outer time steps up to picoseconds can be employed to accurately calculate equilibrium and conformational properties. Furthermore, we developed the atomic version of OIN for MTS-MD of a biomolecule in a solvent potential of mean force obtained at sequential MD steps by using the molecular theory of solvation, aka three-dimensional reference interaction site model with the Kovalenko-Hirata closure (3D-RISM-KH). The solvation forces are obtained analytically by converging the 3D-RISM-KH integral equations once per several OIN outer time steps, and are calculated in between by using solvation force-coordinate extrapolation (SFCE) in the subspace of previous successive solutions to 3D-RISM-KH. For illustration, we applied the multiscale OIN/SFCE/3D-RISM-KH algorithm to a fully flexible model of alanine dipeptide in aqueous solution. Although the computational rate of solvent sampling in OIN/SFCE/3D-RISM-KH is already 20 times faster than standard MD with explicit solvent, further substantial acceleration of sampling stems from making solute evolution steps in a statistically averaged potential of mean force obtained from 3D-RISM-KH. The latter efficiently samples the phase space for essential events with rare statistics such as exchange and localisation of solvent and ligand molecules in confined spaces, pockets and at binding sites of the solute macromolecule, as distinct from MD with explicit solvent which requires enormous computational time and number of steps in such cases. © 2013 Taylor & Francis Group, LLC.
Keywords: Alanine dipeptides; Computational time; Confined space; Conformational properties; Conformational space; Efficient sampling; Explicit solvents; Flexible model; Ligand molecules; Localisation; MD simulation; Molecular dynamics simulations; Molecular systems; Molecular theory of solvation; Multiple time step; Multiscales; Phase spaces; Picoseconds; Potential of mean force; Reference interaction site models; Solvation forces; Time step; Algorithms; Amino acids; Conformations; Phase space methods; Solvents; Three dimensional computer graphics

Biomolecule delivery into canola protoplasts by centrifuging cells with microbubbles - He, Chuan; Gu, Quanrong; Huang, Min; Xing, James; Chen, Jie (FEBS Letters, 2012)
We have successfully delivered FITC and FITC-Dextran (70, 250 kDa) into canola protoplasts by centrifuging cells with different amounts of microbubbles at variable centrifuge speed. The efficiency is around 90%, while cell viability remains high. Confocal microscopy images show that both FITC and FITC-Dextran are scattered inside the cytoplasm and the cell nucleus. Pores are observed on canola protoplast cell membranes and cell walls when centrifuged with microbubbles, while the membrane of cells centrifuged alone remain intact and smooth. We hypothesize that the collision between the microbubbles and cells or the bursting of microbubbles are the main reasons for the formation of these pores. Biomaterials can diffuse into the cells once the pathway is created. © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Keywords: fluorescein isothiocyanate dextran; cell membrane; cell nucleus; cell transport; cell viability; cell wall; confocal microscopy; cytoplasm; flow cytometry; microbubble; protoplast; Biological Transport; Brassica; Cell Survival; Centrifugation; Cytological Techniques; Diffusion; Drug Delivery Systems; Fluorescein-5-isothiocyanate; Microbubbles; Protoplasts; Brassica napus var. napus

Direct spectroscopic monitoring of conductance switching in polythiophene memory devices - Shoute, Lian C. T.; Wu, Yiliang; McCreery, Richard L. (Electrochimica Acta, 2012)
A large number of nonvolatile memory devices have been reported with both inorganic and organic components, and many of these involve changes in device resistance between a high conductivity "ON" state and a low conductivity "OFF" state. The mechanism of memory action in many of these devices is uncertain, and may be based on many phenomena, including redox reactions, metal filament formation, charge storage in "floating gates", and redistribution of oxide vacancies. We report here a Raman spectroscopic probe of organic polymer memory devices which permits direct monitoring of the doping state and conductivity of polythiophene in a 3-terminal device. The polymer conductance is controlled by voltage pulses between the source and gate electrodes in FET geometry, while the conductance state is read out by a separate circuit between source and drain. The conductance was directly correlated with the Raman determination of the density of polarons in the polymer film, which was shown to control both the "electroforming" process and the conductance switching in working memory devices. The polymer conductance change requires a redox counter-reaction at the gate electrode, and atmospheric effects on performance indicate that water and oxygen reduction are involved. The observations are consistent with a redox process between the gate and source electrodes which modulates the polaron concentration and source-drain conductivity. This mechanism provides a framework for optimization of the device by changing its composition and geometry, particularly the identity of the redox counter-reaction and control of ion mobility. © 2012 Elsevier Ltd. All rights reserved.
Keywords: Solid state redox; Poly-thiophene; Atmospheric effects; Conductance switching; Mechanism of memory; Non-volatile memory; Nonvolatile memory devices; Raman spectroscopic; Spectroscopic monitoring; Electrolytic reduction; Molecular electronics; Nonvolatile storage; Organic polymers; Polarons; Polymer films; Redox reactions; Refractory metal compounds; Semiconductor doping

Flux engineering for indium tin oxide nanotree crystal alignment and height-dependent branch orientation - Beaudry, Allan L.; Laforge, Joshua M.; Tucker, Ryan T.; Li, Peng; Taschuk, Michael T.; Brett, Michael J. (Crystal Growth and Design, 2012)
Single-crystal indium tin oxide (ITO) nanotrees with engineered trunk and branch orientations are grown using a recently reported technique combining vapor-liquid-solid growth and glancing angle deposition (VLS-GLAD). In this work, three unique capabilities of VLS-GLAD are demonstrated for the first time: (i) nanotrees are aligned without epitaxy, (ii) branches can be placed on select faces of the nanotree trunk, and (iii) branch orientation can be modified along the height of nanotrees. VLS-GLAD uses a collimated obliquely incident vapor flux to place material on desired growth surfaces, resulting in preferential branch growth on the sides of the nanotree trunk exposed to the flux at the time of nucleation. Dynamic control of the azimuthal orientation of the flux relative to a growing nanotree enables the preferential orientation of branches to be modulated along the height of the nanotree, which we have demonstrated with both continuous and discrete substrate rotation schemes. An electron diffraction investigation confirms that the nanotrees can be considered as a single crystal, with continuity of the crystal structure across the trunk-branch interface. Crystal texture of the films is characterized by X-ray diffraction pole figures. By limiting the flux to discrete positions, the films develop both out-of-plane and in-plane crystal alignment (biaxial texture). We interpret the in-plane orientation as the result of competitive growth, which leads to evolutionary selection of similarly oriented structures. Control over in-plane nanotree crystal alignment and height-dependent branch orientation should increase the achievable complexity in three-dimensional nanowire architectures. © 2012 American Chemical Society.
Keywords: Azimuthal orientation; Biaxial textures; Competitive growth; Crystal texture; Dynamic controls; Glancing Angle Deposition; Growth surfaces; In-plane orientation; Indium tin oxide; Nanotrees; Oriented structure; Out-of-plane; Pole figure; Preferential orientation; Substrate rotation; Vapor fluxes; Vapor-liquid-solid growth; Alignment; Indium compounds; Nanowires; Vapors; X-ray diffraction; Crystal orientation

Label-free impedimetric immunosensor for ultrasensitive detection of cancer marker Murine double minute 2 in brain tissue - Elshafey, Reda; Tlili, Chaker; Abulrob, Abedelnasser; Tavares, Ana C.; Zourob, Mohammed (Biosensors and Bioelectronics, 2012)
The detection of cancer biomarkers is as important tool for the diagnosis and prognosis of cancer such as brain cancer. Murine double minute 2 (MDM2) has been widely studied as prognostic marker for brain tumor. Here we describe development of a new sensitive label free impedimetric immunosensor for the detection of MDM2 based on cysteamine self assembled monolayers on a clean polycrystalline Au electrode surface. The amine-modified electrodes were further functionalized with antibody using homobifunctional 1,4-phenylene diisothiocyanate (PDITC) linker. The assembly processes of the immunosensor had been monitored with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques using Fe(CN)6^3-/4- solution as redox probe. The impedance changes upon binding of MDM2 protein to the sensor surface was utilized for the detection of MDM2. The increase in relative electron-transfer resistance (ΔR/R0%) values was linearly proportional to the concentration of tumor marker MDM2 in the wide dynamic range of 1pg/ml-1μg/ml. The limit of detection was 0.29pg/ml in phosphate buffer saline (PBS) and 1.3pg/ml in mouse brain tissue homogenate, respectively. The immunosensor showed a good performance in comparison with ELISA for the analysis of the MDM2 in the cancerous mouse brain tissue homogenates. Moreover, the immunosensor had a good selectivity against epidermal growth factor receptor (EGFR) protein, long-storage stability and reproducibility. It might be become a promising assay for clinical diagnosis and early detection of tumors. © 2012 Elsevier B.V..
Keywords: MDM2; Cancer biomarker; Brain tissue; Cysteamine; Immunosensor; 1,4-phenylene diisothiocyanate; Electrochemical impedance spectroscopy

Millimeter emission structure in the first alma image of the AU Mic debris disk - MacGregor, Meredith A.; Wilner, David .J.; Rosenfeld, Katherine A.; Andrews, Sean M.; Matthews, Brenda; Hughes, A. Meredith; Booth, Mark; Chiang, Eugene; Graham, James R.; Kalas, Paul; Kennedy, Grant; Sibthorpe, Bruce (The Astrophysical Journal Letters, 2012)
We present 1.3 mm ALMA Cycle 0 observations of the edge-on debris disk around the nearby, ∼10 Myr old, M-type star AU Mic. These observations obtain 0.″6 (6 AU) resolution and reveal two distinct emission components: (1) the previously known dust belt that extends to a radius of 40 AU and (2) a newly recognized central peak that remains unresolved. The cold dust belt of mass ∼1 MMoon is resolved in the radial direction with a rising emission profile that peaks sharply at the location of the outer edge of the "birth ring" of planetesimals hypothesized to explain the midplane scattered light gradients. No significant asymmetries are discerned in the structure or position of this dust belt. The central peak identified in the ALMA image is ∼6 times brighter than the stellar photosphere, which indicates an additional emission process in the inner regions of the system. Emission from a stellar corona or activity may contribute, but the observations show no signs of temporal variations characteristic of radio-wave flares. We suggest that this central component may be dominated by dust emission from an inner planetesimal belt of mass ∼0.01 MMoon, consistent with a lack of emission shortward of 25 μm and a location ≲3 AU from the star. Future millimeter observations can test this assertion, as an inner dust belt should be readily separated from the central star at higher angular resolution. © 2013. The American Astronomical Society. All rights reserved.

Semantic distance measures with distributional profiles of coarse-grained concepts - Hirst, Graeme; Mohammad, Saif (Modeling, Learning, and Processing of Text Technological Data Structures, 2012)
Although semantic distance measures are applied to words in textual tasks such as building lexical chains, semantic distance is really a property of concepts, not words. After discussing the limitations of measures based solely on lexical resources such as WordNet or solely on distributional data from text corpora, we present a hybrid measure of semantic distance based on distributional profiles of concepts that we infer from corpora. We use only a very coarse-grained inventory of concepts - each category of a published thesaurus is taken as a single concept - and yet we obtain results on basic semantic-distance tasks that are better than those of methods that use only distributional data and are generally as good as those that use fine-grained WordNet-based measures. Because the measure is based on naturally occurring text, it is able to find word pairs that stand in non-classical relationships not found in WordNet. It can be applied cross-lingually, using a thesaurus in one language to measure semantic distance between words in another. In addition, we show the use of the method in determining the degree of antonymy of word pairs.

Plasma actuation control of boundary layer flashback in lean premixed combustor - Versailles, Philippe; Chishty, Wajid Ali; Vo, Huu Duc (Proceedings of the ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. Volume 2: Combustion, Fuels and Emissions, Parts A and B, 2012)
Dry low emissions premixed combustion systems have the ability to give larger NOx emissions reduction in comparison to diffusion type of combustors. However, these systems are prone to flashback because the fuel and oxidizers are mixed upstream of the combustion chamber. This is particularly true for premixed systems burning high-reactivity fuels due to their higher flame speed. Flashback is undesirable in gas turbines because it leads to overheating and failure of fuel nozzles and premixing sections. Recently, a novel application of Plasma Actuation through non-thermal Dielectric Barrier Discharge has been shown to significantly delay flashback in the core flow along the axis of the premixer. Building on this successful endeavour, efforts were directed to prove the effectiveness of the control method in situations where flashback was triggered in the boundary layer. Results show that the current application delays the occurrence of flashback in the boundary layer of the premixer to higher equivalence ratios. Improvements in the combustor operability margin of 10 to 14% when burning natural gas-air mixtures, and of about 3.5% when replacing the fuel by an equimolar mixture of natural gas and hydrogen, were achieved. It was found that the proposed application of plasma actuation is even more efficient in preventing flashback in the boundary layer than in the core flow.
Keywords: Dielectric barrier discharges; Emissions reduction; Equimolar mixtures; Equivalence ratios; Lean premixed combustors; Natural gas-air mixture; Novel applications; Premixed combustion; Boundary layers; Combustion; Combustion chambers; Combustors; Emission control; Exhibitions; Fuels; Mixtures; Natural gas; Gas turbines

Erosion resistance of titania co-doped yttria stabilized zirconia - O'Brien, Adam; Huang, Xiao; Yang, Q. (Proceedings of the ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. Volume 5: Manufacturing Materials and Metallurgy; Marine; Microturbines and Small Turbomachinery; Supercritical CO2 Power Cycles, 2012)
The standard yttria-stabilized zirconia (YSZ) has been used as thermal barrier coatings (TBCs) in the hot sections of gas turbine engines for several decades. To achieve further improvement to the thermal insulation capability of current TBCs, doping of alternative oxides to zirconia or co-doping of oxides to YSZ has been employed. In our previous study, it has been shown that doping of 7YSZ with titania (TiO2) reduces thermal conductivity of 7YSZ substantially. As TBCs are susceptible to various failure mechanisms, in this study the erosion resistance of TiYSZ at high impingement speed and angle is evaluated along with measurements of hardness (H) and elastic modulus (E). Specimens with 5 different TiO2 doping amounts (5%, 7.5%, 10%, 12.5% and 15%) are fabricated using plasma spraying and high temperature sintering. The erosion test results show that sample with 5% TiO2 (5TiYSZ) suffers the most erosion damage at high impingement angle due to brittle fracture while 10-15TiYSZ samples exhibit less brittle erosion damage which leads to lower erosion rates under the same test condition. When comparing the erosion rates (defined as the loss of sample mass per mass unit of abrasive particles) to the hardness values, they were found to follow the same trend. The addition of TiO2 (10-15 wt%) had the effect of reducing the erosion rate of 7YSZ at high impingement angle.
Keywords: Abrasive particles; Erosion resistance; Failure mechanism; High-temperature sintering; Impingement angle; Thermal barrier coating (TBCs); Thermal insulation capabilities; Yttria-stabilized zirconias (YSZ); Brittle fracture; Exhibitions; Gas turbines; Hardness; Plasma spraying; Thermal barrier coatings; Thermal conductivity; Titanium dioxide; Yttria stabilized zirconia; Zirconia; Erosion

Evaluation of the impact of alternative fuel use on the emissions and performance of a service-exposed T56 engine - Chalmers, Jennifer L. Y.; Davison, Craig R.; Chishty, Wajid A.; Bird, Jeff W.; Chan, Tak; Barton, Peter; Dagenais, Rod; Pham, Vinh; Poitras, Pierre (Proceedings of the ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. Volume 1: Aircraft Engine; Ceramics; Coal, Biomass and Alternative Fuels; Controls, Diagnostics and Instrumentation, 2012)
Alternative fuel sources are becoming an operational reality; these fuels have the potential to reduce emissions, improve combustion characteristics and to increase fuel supply security. A test with a T56 turboprop engine was performed to demonstrate that a CHEFA/JP8 (Camelina Hydroprocessed Ester and Fatty Acids and standard JP8) fuel blend would meet operational requirements. The primary test objective was to assess whether a fuel change had an immediate impact on the engine condition, performance, emissions or vibration characteristics. This paper presents test results comparing engine performance with JP8 and a 50/50 blend of JP8 and CHEFA. Comparison runs were conducted before and after a 20 hour ground durability test with the CHEFA fuel blend. A nearly time-expired, nacelle-dressed T56 on an outdoor test stand was tested. The engine was equipped with minimallyintrusive non-standard pressure, temperature and emissions monitoring equipment, and a field vibration assessment suite in addition to the standard flight instrumentation. This paper discusses the test plan, data acquisition methods, results and data repeatability. The performance and emissions results are compared to the changes predicted theoretically from the fuel properties. Observations from the borescope inspections before, during and after the 20 hour durability test are also presented. The lessons learned in this test could be applied to future fuel or process-change tests, and the results provide a performance baseline for engine health assessment. Copyright © 2012 by Her Majesty the Queen in Right of Canada
Keywords: Borescope inspection; Combustion characteristics; Emissions monitoring; Engine performance; Flight instrumentations; Operational requirements; Performance and emissions; Vibration characteristics; Alternative fuels; Engines; Exhibitions; Gas turbines; Durability

Morphology control and nanoscale patterning of small molecule organic thin films - Van Dijken, Jaron G.; Wu, Nathanael L.-W.; Fleischauer, Michael D.; Buriak, Jillian M.; Brett, Michael J. (Organic Photonics V, 2012)
We present methods for nanostructuring organic thin films for organic photovoltaic (OPV) devices. Using the glancing angle deposition (GLAD) technique, we fabricate a variety of columnar morphologies of metal phthalocyanine (MPc) materials that can be used as structured donor layers in OPV devices. We leverage this capability with block copolymer surface patterning techniques to achieve perfectly periodic columnar arrays while providing additional control over column dimensions, spacing, and density. Our investigation employs hexagonal seed patterns of platinum on silicon and we vary the seed spacing between 40 nm and 60 nm. We find that pattern resemblance begins to fade when the film thickness exceeds the seed spacing. We compare the film evolution between vertical post and slanted post morphologies, and use advanced substrate motion techniques to constrain column diameters. We conclude by addressing the compatibility of surface patterning with device fabrication. Patterned ITO surfaces and SiO 2 seed patterns are shown.
Keywords: Additional control; Column dimensions; Columnar arrays; Columnar morphology; Device fabrications; Donor layers; Film evolution; Glancing Angle Deposition; Glancing angle deposition technique; Metalphthalocyanines; Morphology control; Motion techniques; Nano-structuring; Nanoscale patterning; Organic photovoltaic devices; Organic photovoltaics; Organic thin films; Patterned ITO; Seed spacing; Small molecules; Surface patterning; Vertical posts; Zinc phthalocyanines; Block copolymers; Lithography; Morphology; Photovoltaic effects; Platinum; Silicon oxides; Surfaces; Thin films; Zinc compounds; Vapor deposition

Statistical-mechanical, molecular theory of boundary conditions for liquid flow at nanostructured surfaces and in confined geometries - Kovalenko, A. (Procedia Engineering, 2012)

Multiple regression analysis of the impact of track geometry on wheel-rail forces - Huang, W.; Liu, Y.; Preston-Thomas, J. (2012 Joint Rail Conference, JRC 2012, 2012)
One of the fundamental keys to improving track safety standards is to establish a strong correlation between track geometry variations and wheel-rail force parameters that are indicators of vehicle-track safety performance. In this study, wheel-rail forces were collected during field tests of a loaded lumber car and an empty tank car. Computer models of the two tested freight cars were built, and the models were calibrated using field test results. The computer models were then used to evaluate the impact of varying track geometry parameters on track safety using the maximum single wheel L/V ratio, maximum truck side L/V ratio, and minimum vertical wheel load ratio. It was confirmed again that the correlations between these force parameters and any individual geometry parameter were weak. With further investigation, it was found that much better correlation can be achieved using multiple regression techniques to define each wheel-rail force parameter as a function of all track geometry parameters combined together. Expressions of the maximum truck side L/V ratio, maximum single wheel L/V ratio, and minimum vertical wheel load ratio were obtained as functions of curvature, cross level, alignment, gauge, and cant deficiency using multiple regression analysis. Copyright © 2012 by ASME.

Genetic characterization of Escherichia coli O157:H7 strains isolated from the one-humped camel (Camelus dromedarius) by using microarray DNA technology - Salehi, T.Z.; Tonelli, A.; Mazza, A.; Staji, H.; Badagliacca, P.; Tamai, I.A.; Jamshidi, R.; Harel, J.; Lelli, R.; Masson, L. (Molecular Biotechnology, 2012)
From the Camelidae family members, several serotypes of Escherichia coli (E. coli) have recently been isolated from diarrhoeic and non-diarrhoeic faecal samples. To date Shiga toxin-producing E. coli (STEC) strains have never been typed in one-humped camel (Camelus dromedarius). In the present study, two E. coli O157:H7 strains isolated from sick dromedaries were investigated. Virulence gene profiles were determined using a custom E. coli virulence DNA microarray, composed of 70-mer oligonucleotide probes targeting 264 virulence or related genes of known E. coli pathotypes. Both strains displayed positive hybridization signals for the Locus of enterocyte effacement (LEE) gene probes (ler, eae, espA, espB, tir genes), two Shiga toxin probes (stx1 and stx2), the O157 O-antigen specific probe, various virulence plasmid (pO157) probes like katP in addition to other accessory virulence genes characterized in STEC.
Keywords: bacterial DNA; virulence factor; animal; animal disease; article; bacterial gene; camel; classification; DNA microarray; Escherichia coli infection; Escherichia coli O157; feces; genetics; isolation and purification; methodology; microbiology; Animals; Camels; DNA, Bacterial; Escherichia coli Infections; Escherichia coli O157; Feces; Genes, Bacterial; Oligonucleotide Array Sequence Analysis; Virulence Factors

Load monitoring of aerospace structures using micro-electro-mechanical systems (MEMS) - Martinez, M.; Rocha, B.; Li, M.; Shi, G.; Beltempo, A.; Rutledge, R.; Yanishevsky, M. (ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2012, 2012)
The National Research Council of Canada has developed Structural Health Monitoring (SHM) test platforms for load and damage monitoring, sensor system testing and validation. One of the SHM platform consists of two 2.25 meter long, simple cantilever aluminium beams that provide a perfect scenario for evaluating the capability of a load monitoring system to measure bending, torsion and shear loads. In addition to static and quasi-static loading procedures, these structures can be fatigue loaded using a realistic aircraft usage spectrum while SHM and load monitoring systems are assessed for their performance and accuracy. In this study, Micro-Electro-Mechanical Systems (MEMS), consisting of triads of gyroscopes, accelerometers and magnetometers, were used to compute changes in angles at discrete stations along the structure. A Least Squares based algorithm was developed for polynomial fitting of the different data obtained from the MEMS installed in several spatial locations of the structure. The angles obtained from the MEMS sensors were fitted with a second, third and/or fourth order degree polynomial surface, enabling the calculation of displacements at every point. The use of a novel Kalman filter architecture was evaluated for an accurate angle and subsequent displacement estimation. The outputs of the newly developed algorithms were then compared to the displacements obtained from the Linear Variable Displacement Transducers (LVDT) connected to the structures. The determination of the best Least Squares based polynomial fit order enabled the application of derivative operators with enough accuracy to permit the calculation of strains along the structure. The calculated strain values were subsequently compared to the measurements obtained from reference strain gauges installed at different locations on the structure. This new approach for load monitoring was able to provide accurate estimates of applied strains and loads. Copyright © 2012 by Her Majesty The Queen in Right of Canada.

Sorption of CO2/CH4 mixtures in PIM-1 and PTMSP membrjanes: Experimental data at 35°C and modeling - Vopicka, O.; De Angelis, M.G.; Sarti, G.C.; Du, N.; Li, N.; Guiver, M.D. (Procedia Engineering, 2012)

The effect of motion on wind tunnel drag measurement for athletes - D'Auteuil, A.; Larose, G.L.; Zan, S.J. (Procedia Engineering, 2012)
To optimize the reduction of the drag area coefficient of a speed skater, mannequins in static positions wearing suits were tested in the NRC 2m × 3m Wind Tunnel to find the lowest drag for a given range of speeds. The results obtained from this study can only be interpreted and applied to a speed skater if the aerodynamic drag coefficient is not affected significantly by the motion of the skater. It has been assumed that, for a representative cadence or frequency of oscillation of a speed skater lower than 1 Hz which is representative of the motion in a race, the aerodynamics could be considered quasi-stationary. The quasi-steady state is defined by the flow that developed around the body and the wake both governing the aerodynamic drag compared to the contribution of the low frequency of oscillation of the body. To verify this hypothesis and to determine to what extent the quasi-steady assumption is valid for a human body in a speed skating position, a study was carried out in a wind tunnel using a moving life-size mannequin. A mechanism was devised so that a mannequin in a sidepush position could be oscillated to mimic the sinusoidal path of a speed skater. The amplitude of motion was kept constant and the frequencies of oscillation and wind speeds were changed to cover the equivalent of 500 m to 10,000 m races. The experiments have revealed that the variations of the drag area coefficient with wind speed were similar for static positions and for cases where the mannequin was oscillating at frequencies lower than 0.67 Hz or for a period of rotation of 1.5 s. The drag reduction occurred at the same wind speeds for the static and dynamic cases. This paper presents details of the experiments and a summary of the main findings. © 2012 Published by Elsevier Ltd.

A molecular simulation study of Pt stability on oxidized carbon nanoparticles - Ban, Shuai; Malek, Kourosh; Huang, Cheng (Journal of Power Sources, 2012)
Molecular simulation is used to model the structural change of carbon nanoparticles in terms of total mass loss during the oxidation process. The density changes as well as simulation snapshots suggest a location-dependent gasification, particularly taking place in the core of the carbon particles. A graphitic shell structure of degraded carbon particles obtained from our simulations is in agreement with experimental observations. In addition, the shrinkage of graphitic crystallites near the carbon surface leads to the formation of micropores, the volume of which increases with the oxidation level. On the basis of this carbon model, the stability of Pt nanoparticles is investigated for various temperatures and roughnesses of the carbon surface. Simulation results show that migration and coalescence of Pt particles indeed occur, but at a low rate. In particular, detachment and transport of small Pt clusters were observed from simulation snapshots, supporting the argument that the transport of molecular Pt species occurs on carbon surface. The thermal activation plays a key role in the deformation of the Pt crystal structure. During simulations, both the size and surface of Pt particles increase at elevated temperature, i.e. 600 °C. However, only a few of the surface Pt atoms may contribute to the catalytic performance due to their site-dependent reactivity.
Keywords: Molecular dynamics; Carbon black; Pt degradation; Fuel cells

Pulsed laser deposition of vanadium-doped manganese oxide thin films for supercapacitor applications - Yang, Dongfang (Journal of Power Sources, 2012)
Thin films of vanadium-doped crystalline Mn2O3 and amorphous MnOx have been grown by the pulsed laser deposition (PLD) process on silicon wafer and stainless steel substrates at different substrate temperatures and oxygen gas pressures. It was found that V-doping level as low as 3.2 atm. % can transform the crystal structure of a crystalline Mn 2O3 film into a crystalline MnO2 film. V-doping (up to 10 atm. %) has significantly lowered the specific capacitance of the crystalline Mn2O3 films. However, V-doped amorphous MnOx films did significantly increase the specific capacitance at high CV scan rate as compared with the un-doped MnOx films and the specific capacitance of V-doped amorphous films increased linearly with the V atomic percentage. At high scan rate of 100 mV s-¹, 9.7 atm. % V-doped MnOx film reached a high specific capacitance value of 95 F g-#185; indicating that V-doped amorphous MnOx is good candidate active materials for high energy supercapacitors. The results prove that elemental doping can significantly change the electrochemical properties of MnOx films.
Keywords: Electrochemical capacitor; Supercapacitor; Pulsed laser deposition; Vanadium doping; Manganese oxides; Thin films

Troubleshooting the rabbit ferric chloride-induced arterial model of thrombosis to assess in vivo efficacy of antithrombotic drugs - Couture, L.; Richer, L. P.; Mercier, M.; Hélie, C.; Lehoux, D.; Hossain, S. M. (Journal of Pharmacological and Toxicological Methods, 2012)
Introduction: The FeCl3-induced arterial model of thrombosis is one of the most widely used animal models to assess arterial efficacy of new antithrombotic drug candidates. This model is well-established in rodents but in a less extent in the rabbit. In this work, we present a methodology for a rabbit FeCl3-induced arterial model of thrombosis derived from our troubleshooting which allows the generation of reliable efficacy data for new antithrombotic drug candidates. Methods: Rabbits were administered with heparin 4.5U/kg/min, argatroban 10μg/kg/min or saline by intravenous infusion. The blood flow was monitored using a Doppler flow probe. The time from the application of FeCl3 to the recorded zero blood flow was defined as the time to occlusion, with a maximum recording time of 60min post-FeCl3 application. After 30min of infusion, thrombosis was induced by wrapping a FeCl3-saturated filter paper around the carotid artery caudal to the flow probe. Animals were subject to exclusion criteria based on the visual aspect of the artery FeCl3-induced injury and based on changes in blood flow upon FeCl3 application. Results: Following the application of FeCl3, a mean time to occlusion for saline, heparin and argatroban of 24.3±1.8, 52.5±4.8 and 53.5±4.5min was obtained, respectively. Mean time to occlusion for heparin and argatroban administered groups was significantly different when compared to the saline-treated group (p<0.05). These results for the test compounds represent approximately 80% of the maximum possible prolongation. Discussion: The rabbit FeCl3-induced arterial model of thrombosis presented in this paper derived from our troubleshooting is sensitive and reproducible for the generation of accurate and reliable efficacy data in the assessment of new antithrombotic agents in preclinical drug development. © 2012.
Keywords: Antithrombotic drug; Blood flow; Ferric chloride; Methods; Rabbit; Time to occlusion

Dynamics of brain structure and cognitive function in the Alzheimer's disease neuroimaging initiative - Song, Xiaowei; Mitnitski, Arnold; Zhang, Ningnannan; Chen, Wei; Rockwood, Kenneth (Journal of Neurology, Neurosurgery and Psychiatry, 2012)
Background: On average, cognition declines as people age, but improvement can also occur. Objective: To evaluate the dynamics of age-related changes in brain structure and cognitive function in patients with mild Alzheimer's disease (AD) and mild cognitive impairment (MCI) and in healthy control (HC) older adults. Methods: High-resolution 3-Tesla MRI and clinical data were obtained from the Alzheimer's Disease Neuroimaging Initiative in 187 subjects (a cohort aged 55-91 years; AD=43, MCI=84, HC=60). At 24 months, 151 people had clinical and 128 had MRI follow-up. Brain structure was assessed using the Medial Temporal Atrophy Scale (MTAS) and the Brain Atrophy and Lesion Index (BALI). Cognition was assessed using the Mini-Mental State Examination (MMSE) and the Alzheimer Disease Assessment Scale-cognitive subscale (ADAS-cog). Responsiveness was tested. Changes were analysed using a multistate dynamic model, adjusted for age, gender, ApoE4 genotype and vascular risk factors. Results: Over 2 years, decline in brain structure and cognition predominated, each showing detectable effect sizes (Cohen's d=0.33 for MTAS, 0.32 for BALI, 0.41 for MMSE, 0.38 for ADAS-cog; standard response mean=0.71, 0.69, 0.50 and 0.47, respectively). Structural improvement was observed (10.2% in BALI and 0.8% in MTAS), as was cognitive improvement (23.2% MMSE, 27.2% ADAS-cog). Most people (66.7%) whose BALI score improved also improved in either the MMSE or ADAS-cog. No patient with MCI whose MTAS or BALI improved converted to AD. Conclusions: Despite average decline in brain structure, improvement was observed and related to cognition and MCI-AD conversion. Ageing-related brain changes reflect a dynamic process.

Evaluation of systematic shifts for the 88Sr+ 445-THz reference transition at the 10-17 level using the NRC next generation ion trap system - Madej, A. A.; Dubé, P.; Zhou, Z.; Bernard, J. E. (2012 Conference on Precision Electromagnetic Measurements, 2012)
We describe receent progress in the establishment of a versatile and reliable optical frequency standard whose performance in evaluated accuracy and stability exceeds that of the current realization of the SI second. The 445-THz reference transition in a single, trapped, and laser cooled ion of 88Sr⁺ suspended using a miniature RF endcap trap system in the new trap have been reduced to the 2 x 10⁻¹⁷ level for each of the scalar Stak shifts and the time dilation shifts. Studies indicate that such shifts remain stable over several hours. An identical trap system was constructed to evaluate the electrode heating effects of the shift will be limited by the current knowledge of the scalar polarizabilities of the upper and lower states of the reference transition, currently at the 2 x 10⁻¹⁷ level.
Keywords: Clocks; frequency control; ions; lasers; precision mesurements; spectroscopy; start effect; strontium

Exchange, correlation, and the effective mass m* of electrons in two-dimensional layers calculated via a DFT-based classical map - Dharma-Wardana, M. W. C. (International Journal of Quantum Chemistry, 2012)
Density functional theory uses the electron density n(r), instead of the electronic wavefunction. We side-step the kinetic energy functional by constructing a thermodynamically equivalent classical map (CM). A classical Coulomb fluid whose zeroth-order pair-distribution function (PDF) g 0(r) that agrees with the quantum g0, and interacting via a "Pauli exclusion potential" reproduces the thermodynamics of the electron fluid, when the classical-fluid temperature Tcf is chosen optimally. This Tcf is chosen so that the correlation energy of the classical fluid is the Kohn-Sham correlation energy. Then, the PDFs of the classical fluid closely agree with the PDFs of the two-dimensional (2D) and 3D uniform electron systems. Can we calculate sensitive Fermi-liquid properties (e.g., quasiparticle mass m*, Landé g-factor) of interacting electrons via this CM? Given the wide interest in the effective mass m* of electrons in 2D layers, we chose the 2D system for this study. Analytical and numerical results are used to define a partially regularized m* valid to logarithmic accuracy in the sense of Landau for the Hartree-Fock (H-F) approximation. The resulting H-F m* decreases linearly with the electron-disk radius rs. The m* including correlation is calculated via a physically transparent formula. This uses the CM of the 2D PDF and its finite-T exchange-correlation free energy Fxc(T). Our results for m* fall well within the results from recent quantum Monte-Carlo simulations at T = 0, and other theoretical and experimental results.
Keywords: 2-D systems; 2D layer; Classical fluids; Correlation energy; DFT-based; Effective mass; Electron fluid; Electron systems; Electronic wave functions; Energy functionals; Exchange-correlations; Fermi-liquid properties; Finite temperatures; G factors; Hartree-fock; Interacting electrons; Kohn shams; Landau-fermi liquids; Pair distribution functions; Pauli exclusion; Quantum Monte Carlo simulations; Quasi particles; D region; Density functional theory; Intelligent systems; Kinetics; Thermodynamics

Smart gold nanoparticles enhance killing effect on cancer cells - Song, Kun; Xu, Peng; Meng, Yongde; Geng, Feng; Li, Jie; Li, Zhao; Xing, James; Chen, Jie; Kong, Beihua (International Journal of Oncology, 2012)
The present study explored the cellular uptake dynamics, the subcellular location and the internalization mechanisms of gold nanoparticles (GNPs) and glucose-capped GNPs (Glu-GNPs). The cancer radiotherapy-enhancing effects of GNPs were also evaluated. We synthesized the GNPs and Glu-GNPs by the seeding technique. The effects on cellular uptake and the radiosensitizing effect induced by GNPs and Glu-GNPs at lower doses were investigated using two human cancer cell lines (HeLa and MCF-7). The intracellular location of the nanoparticles was analyzed by transmission electron microscopy (TEM). Analysis of cellular apoptosis following GNP-based radiotherapy was performed by flow cytometry and TUNEL assay. Cancer cells took up more Glu-GNPs than naked GNPs and the uptake curve showed size- and cell-dependent uptake. GNPs were mainly located in the cytoplasm and endocytosis is the mechanism behind the internalization of GNPs and Glu-GNPs. Lower doses of GNPs and Glu-GNPs still enhanced the killing effect using X-ray irradiation, although the apoptotic rate was not altered. The results presented in this study provide evidence that Glu-GNPs may have a bright future in tumor-targeted diagnosis and treatment.
Keywords: glucose capped gold nanoparticle; radiosensitizing agent; unclassified drug; antineoplastic activity; apoptosis; cancer radiotherapy; cell killing; cellular distribution; comparative study; controlled study; cytoplasm; drug effect; drug uptake; endocytosis; flow cytometry; human cell; internalization; nick end labeling; radiosensitization; transmission electron microscopy; X irradiation

Alzheimer's disease: An update of the roles of receptors, astrocytes and primary cilia (Review) - Armato, Ubaldo; Chakravarthy, Balu; Pacchiana, Raffaella; Whitfield, James F. (International Journal of Molecular Medicine, 2012)
The pathophysiological mechanisms underlying the onset and inexorable progression of the late-onset form of Alzheimer's disease (AD) are still the object of controversy. This review takes stock of some most recent advancements of this field concerning the complex roles played by the amyloid-β (Aβ)-binding p75 neurotrophin receptor (p75NTR) and calcium-sensing receptor (CaSR) and by the primary cilia in AD. Apart from their physiological roles, p75NTR is more intensely expressed in the hippocampus of human AD brains and Aβ-bound p75NTR triggers cell death, whereas Aβ-bound CaSR signalling induces the de novo synthesis and release of nitric oxide (NO), vascular endothelial growth factor (VEGF)-A and Aβ peptides (Aβs), particularly on the part of normal adult human astrocytes. The latter effect could significantly increase the pool of Aβ-and NO-producing nerve cells favouring the progressive spread of a self-sustaining and self-reinforcing 'infectious' mechanism of neural and vascular (i.e. blood-brain barrier) cell damage. Interestingly, primary cilia concentrate p75NTR receptors in their membranes and are abnormally structured/damaged in transgenic (Tg) AD-model mice, which could impact on the adult neurogenesis occurring in the dentate gyrus's subgranular zone (SGZ) that is necessary for new memory encoding, thereby favouring typical AD cognitive decline. Altogether, these findings may pave the way to novel therapeutic approaches to AD, particularly in its mild cognitive impairment (MCI) and pre-MCI stages of development.
Keywords: amyloid beta protein; amyloid beta-peptides; calcium sensing receptor; glial fibrillary acidic protein; guanosine triphosphate cyclohydrolase I; inducible nitric oxide synthase; neurotrophin receptor p75; protein Patched; protein tyrosine kinase A; smoothened protein; somatomedin C receptor; sonic hedgehog protein; tetrahydrobiopterin; vasculotropin A; cell damage; ciliary body; dentate gyrus; enzyme activity; granule cell; intracellular signaling; mild cognitive impairment; nerve cell necrosis; nerve cell primary cilia; neural stem cell; neuroblastoma cell; protein expression; protein phosphorylation; signal transduction; cell Death; dentate gyrus; hippocampus; neurogenesis; neurons; receptor, nerve growth factor; receptors, calcium-sensing; signal transduction

Curvature analysis to differentiate magnetic sources for geologic mapping - Lee, Madeline; Morris, William; Leblanc, George; Harris, Jeff (Geophysical Prospecting, 2012)
Curvature of a surface is typically applied in seismic data interpretation; however this work outlines its application to a potential field, specifically aeromagnetic data. The curvature of a magnetic grid (from point data) is calculated by fitting a quadratic surface within a moving window at each grid node. The overall and directional curvatures calculated within this window provide insight into the geometry of the magnetic grid surface and causative sources. Curvature analysis is an in-depth study of both qualitative (graphically) and quantitative (statistically) approaches. This analysis involved the calculation of full, profile and plan curvatures. The magnitude, sign and relative ratios enable the user to define source location and geometry and also discriminate source type; for example, differentiation between a fault and normal polarity dyke. The reliability of the analysis is refined when a priori geological knowledge is available and basic statistics are considered. By allotting a weighting scheme to various statistical populations (e.g., standard deviation), increased detail is extracted on the different lithologies and structures represented by the data set. Furthermore, the curvature's behaviour is analogous to derivative calculation (vertical, horizontal and tilt) by producing a zero value at the source edge and either a local maxima or minima over the source. Application prior to semi-automated methods may help identify correct indices necessary for identification of magnetic sources. Curvature analysis is successfully applied to an aeromagnetic data set over the 2.6-1.85 Ga Paleoproterozoic Wopmay orogen, Northwest Territories, Canada. This area has undergone regional and local-scale faulting and is host to multiple generations of dyke swarms. As the area has been extensively mapped, this data set proved to be an ideal test site.
Keywords: Magnetics; Potential Field; Signal Processing; Data Processing

A comparative life cycle assessment of diesel and compressed natural gas powered refuse collection vehicles in a Canadian city - Rose, Lars; Hussain, Mohammed; Ahmed, Syed; Malek, Kourosh; Costanzo, Robert; Kjeang, Erik (Energy Policy, 2012)
Consumers and organizations worldwide are searching for low-carbon alternatives to conventional gasoline and diesel vehicles to reduce greenhouse gas (GHG) emissions and their impact on the environment. A comprehensive technique used to estimate overall cost and environmental impact of vehicles is known as life cycle assessment (LCA). In this article, a comparative LCA of diesel and compressed natural gas (CNG) powered heavy duty refuse collection vehicles (RCVs) is conducted. The analysis utilizes real-time operational data obtained from the City of Surrey in British Columbia, Canada. The impact of the two alternative vehicles is assessed from various points in their life. No net gain in energy use is found when a diesel powered RCV is replaced by a CNG powered RCV. However, significant reductions (approximately 24% CO2-equivalent) in GHG and criteria air contaminant (CAC) emissions are obtained. Moreover, fuel cost estimations based on 2011 price levels and a 5-year lifetime for both RCVs reveal that considerable cost savings may be achieved by switching to CNG vehicles. Thus, CNG RCVs are not only favorable in terms of reduced climate change impact but also cost effective compared to conventional diesel RCVs, and provide a viable and realistic near-term strategy for cities and municipalities to reduce GHG emissions.
Keywords: Life cycle assessment (LCA); Compressed natural gas (CNG); Refuse collection vehicle (RCV)

Charging and discharging electrochemical supercapacitors in the presence of both parallel leakage process and electrochemical decomposition of solvent - Ban, Shuai; Zhang, Jiujun; Zhang, Lei; Tsay, Ken; Song, Datong; Zou, Xinfu (Electrochimica Acta, 2012)
Simple models for electrochemical supercapacitors are developed to describe the charge-discharge behaviors in the presence of both voltage-independent parallel leakage process and electrochemical decomposition of solvent. The models are validated by experimental data collected using a symmetric two-electrode test cell with carbon powder as the electrode layer material and stainless steel as the current collector.
Keywords: Electrochemical supercapacitor; Charge and discharge; Parallel leakage; Self-discharging; Solvent decomposition

Crowdsourcing a word-emotion association lexicon - Mohammad, Saif M.; Turney, Peter D. (Computational Intelligence, 2012)
Even though considerable attention has been given to the polarity of words (positive and negative) and the creation of large polarity lexicons, research in emotion analysis has had to rely on limited and small emotion lexicons. In this paper, we show how the combined strength and wisdom of the crowds can be used to generate a large, high-quality, word-emotion and word-polarity association lexicon quickly and inexpensively. We enumerate the challenges in emotion annotation in a crowdsourcing scenario and propose solutions to address them. Most notably, in addition to questions about emotions associated with terms, we show how the inclusion of a word choice question can discourage malicious data entry, help to identify instances where the annotator may not be familiar with the target term (allowing us to reject such annotations), and help to obtain annotations at sense level (rather than at word level). We conducted experiments on how to formulate the emotion-annotation questions, and show that asking if a term is associated with an emotion leads to markedly higher interannotator agreement than that obtained by asking if a term evokes an emotion.
Keywords: affect; Crowdsourcing; emotion lexicon; emotions; Mechanical turks; polarity lexicon; Semantic orientation; Sentiment analysis; Artificial intelligence; Computational methods; Semantics

Ecotoxicity of xanthene dyes and a non-chlorinated bisphenol in soil - Ritchie, Ellyn E.; Princz, Juliska I.; Robidoux, Pierre Yves; Scroggins, Rick P. (Chemosphere, 2012)
Soil eco-toxicity testing was conducted in support of Canada's Chemical Management Plan (CMP) to fill data gaps for organic chemicals known to primarily partition to soil, and of which the persistence and inherent toxicity are uncertain. Two compounds representative of specific classes of chemicals: non-chlorinated bisphenols containing an -OH group (4,4'-methylenebis(2,6-di-tert-butylphenol (Binox)) and xanthene dyes (2',4',5',7'-tetrabromo-4,5,6,7-tetrachloro-3',6'-dihydroxy-, disodium salt (Phloxine B), 2',4',5',7'-tetrabromofluorescein (TBF), 4',5'-dibromofluorescein (DBF), and 4,5,6,7-tetrachlorofluorescein (TCF)) were evaluated. The effect of these substances on plant growth (Elymus lanceolatus and Trifolium pratense) and soil invertebrate survival and reproduction (Folsomia candida and Eisenia andrei) were assessed using a field-collected sandy soil. Binox was persistent throughout testing (up to 63d) with an average recovery of 77±2.9% at test end. Binox was not toxic to plants (IC50s>1076mgkg-¹) or E. andrei (IC50s>2651mgkg-¹); however, a significant reduction in F. candida adult survival and reproduction (IC50=89 (44-149) mgkg-¹) was evident. Phloxine B was also persistent throughout testing, with an average recovery of 82±3.0% at test end. Phloxine B was significantly more toxic than Binox, with significant reductions in plant root growth (IC50s≥11mgkg-¹) and invertebrate reproduction (IC50s≥22mgkg-¹). DBF toxicity was not significantly different from that of Phloxine B for plant root growth (IC50s≥30mgkg-¹), but was significantly less toxic for shoot growth (IC50s≥1758mgkg-¹), and invertebrate adult survival (IC50s≥2291mgkg-¹) and reproduction (IC50s≥451mgkg-¹). A comparison between all four xanthene dyes was completed using F. candida, with the degree of toxicity in the order of Phloxine B≥TBF~DBF>TCF. The results from these studies will contribute to data gaps for poorly understood chemicals (and chemical groupings) under review for environmental risk assessments, and will aid in the validation of model predictions used to characterize the fate and effects of these substances in soil environments.

Quantification of strain through linear dichroism in the Si 1s edge X-ray absorption spectra of strained Si1-xGex thin films - Cao, W.; Masnadi, M.; Eger, S.; Martinson, M.; Xiao, Q.-F.; Hu, Y.-F.; Baribeau, J.-M.; Woicik, J. C.; Hitchcock, A. P.; Urquhart, S. G. (Applied Surface Science, 2012)
We have quantitatively measured the angle dependence in the Silicon 1s X-ray absorption spectra of strained Si1-xGex thin films prepared by epitaxial growth on Si(1 0 0) substrates, through surface sensitive total electron yield detection. The linear dichroism difference extracted from these angle dependent X-ray absorption spectra is proportional to the degree of strain, as measured separately by Raman spectroscopy. This quantitative relationship provides a means to measure the compressive strain in Si 1-xGex thin films. This strain-dependent X-ray absorption spectroscopy has the potential to realize a semiconductor strain metrology through high spatial resolution X-ray spectromicroscopy.
Keywords: Angle dependence; Angle-dependent; Compressive strain; High spatial resolution; Linear dichroism; NEXAFS; Si(1 0 0); Silicon-germanium alloys; Strain metrology; Strain-dependent; Strained-Si; Total electron yield; X-ray absorption spectrum; X-ray spectromicroscopy; Absorption spectra; Dichroism; Epitaxial growth; Germanium; Germanium alloys; Raman spectroscopy; Strain; Thin films; X ray absorption spectroscopy; Silicon

Ti4O7 supported Ru@Pt core-shell catalyst for CO-tolerance in PEM fuel cell hydrogen oxidation reaction - Zhang, Lei; Kim, Jenny; Zhang, Jiujun; Nan, Feihong; Gauquelin, Nicolas; Botton, Gianluigi A.; He, Ping; Bashyam, Rajesh; Knights, Shanna (Applied Energy, 2012)
A new method is developed for synthesizing Ti4O7 supported Ru@Pt core-shell catalyst (Ru@Pt/Ti4O7) through pyrolysis followed by microwave irradiation. The purpose is to improve the Ru durability of PtRu from core-shell structure and strong bonding to Ti4O7 oxide. In this method, the first step is to co-reduce the mixture of ruthenium precursor and TiO2 in a H2 reducing atmosphere under heat-treatment to obtain a Ru core on Ti4O7 support, and the second step is to create a shell of platinum via microwave irradiation. Energy dispersive X-ray spectrometry, X-ray Diffraction, High-resolution Scanning Transmission Electron Microscopy with the high-angle annular dark-field method and Electron Energy-Loss Spectroscopy are used to demonstrate that this catalyst with larger particles has a core-shell structure with a Ru core and a Pt shell. Electrochemical measurements show Ru@Pt/Ti4O7 catalyst has a higher CO-tolerance capability than that of PtRu/C alloy catalyst.
Keywords: Alloy catalyst; Carbon monoxide tolerance; Core shell structure; Electrochemical measurements; Energy dispersive X-ray spectrometry; High resolution; High-angle annular dark fields; Hydrogen oxidation reaction; Reducing atmosphere; Ruthenium precursors; Scanning transmission electron microscopy; TiO; Electrocatalysts; Electron energy loss spectroscopy; Platinum alloys; Proton exchange membrane fuel cells (PEMFC); Shells (structures); Titanium dioxide; X ray diffraction; Ruthenium alloys; catalysis; catalyst; electrochemical method; irradiance; microwave radiation; pyrolysis

Biological and physicochemical wastewater treatment processes reduce the prevalence of virulent Escherichia coli - Frigon, Dominic; Biswal, Basanta Kumar; Mazza, Alberto; Masson, Luke; Gehr, Ronald (Applied and Environmental Microbiology, 2012)
Effluents discharged from wastewater treatment plants are possible sources of pathogenic bacteria, including Escherichia coli, in the freshwater environment, and determining the possible selection of pathogens is important. This study evaluated the impact of activated sludge and physicochemical wastewater treatment processes on the prevalence of potentially virulent E. coli. A total of 719 E. coli isolates collected from four municipal plants in Québec before and after treatment were characterized by using a customized DNA microarray to determine the impact of treatment processes on the frequency of specific pathotypes and virulence genes. The percentages of potentially pathogenic E. coli isolates in the plant influents varied between 26 and 51%, and in the effluents, the percentages were 14 to 31%, for a reduction observed at all plants ranging between 14 and 45%. Pathotypes associated with extraintestinal pathogenic E. coli (ExPEC) were the most abundant at three of the four plants and represented 24% of all isolates, while intestinal pathogenic E. coli pathotypes (IPEC) represented 10% of the isolates. At the plant where ExPEC isolates were not the most abundant, a large number of isolates were classified as both ExPEC and IPEC; overall, 6% of the isolates were classified in both groups, with the majority being from the same plant. The reduction of the proportion of pathogenic E. coli could not be explained by the preferential loss of one virulence gene or one type of virulence factor; however, the quinolone resistance gene (qnrS) appears to enhance the loss of virulence genes, suggesting a mechanism involving the loss of pathogenicity islands.
Keywords: After-treatment; DNA micro-array; E. coli; Freshwater environments; Pathogenic bacterium; Pathogenic E. coli; Quinolones; Resistance genes; Treatment process; Virulence factors; Virulence gene; Wastewater treatment plants; Wastewater treatment process; Activated sludge process; Effluents; Pathogens; microbial activity; physicochemical property; genetics; genotype; isolation and purification; microarray analysis; water management; DNA, Bacterial; Genotype; Microarray Analysis; Waste Water; Water Purification

Low-pressure synthesis and characterization of hydrogen-filled ice Ic - Kumar, Rajnish; Klug, Dennis D.; Ratcliffe, Christopher I.; Tulk, Christopher A.; Ripmeester, John .A. (Angewandte Chemie - International Edition, 2012)
A hydrogen storage material: When vapor-deposited amorphous ice is exposed to a low pressure (about 12 MPa) of hydrogen at 140 K a hydrogen-filled cubic ice results (see picture). Calculations suggest that this material has the potential for hydrogen storage with a capacity of 10 wt % hydrogen at full loading.
Keywords: Amorphous ice; Clathrates; Cubic ice; Hydrogen storage materials; Low pressures; Hydrates; Loading; Vapors

Determination of trace elements in fluoropolymers after microwave-induced combustion - Flores, Erico M. M.; Muller, Edson I.; Duarte, Fabio A.; Grinberg, Patricia; Sturgeon, Ralph E. (Analytical Chemistry, 2012)
An effective approach to the digestion of fluoropolymers for the determination of Ag, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, and Ni impurities has been developed using microwave-induced combustion (MIC) in closed quartz vessels pressurized with oxygen. Samples that were examined included the following: polytetrafluorethylene (PTFE); polytetrafluoroethylene with an additional modifier, perfluoropropylvinylether (PTFE-TFM); and fluorinated ethylene propylene (FEP). A quartz device was used as a sample holder, and the influence of the absorber solution was evaluated. Determination of trace elements was performed by inductively coupled plasma-optical emission and mass spectrometry. Neutron activation analysis (NAA) was used for validation purposes. Results were also compared to those obtained using microwave-assisted acid extraction in high-pressure closed systems. Dilute nitric acid (5 mol L-1), which was selected as the absorbing medium, was used to reflux the sample for 5 min after the combustion. Using these conditions, agreement for all analytes was better than 98% when compared to values determined by NAA. The residual carbon content in the digests was lower than 1%, illustrating the high efficiency of the method. Up to 8 samples could be digested within 30 min using MIC, providing a suitable throughput, taking into account the inertness of such samples.
Keywords: Absorbing medium; Acid extraction; Analytes; Closed systems; Fluorinated ethylene propylene; Inductively-coupled; Microwave-assisted; Microwave-induced combustion; Residual carbon; Sample holders; Combustion; Inductively coupled plasma; Manganese; Mass spectrometry; Nitric acid; Quartz; Fluorine containing polymers; politef; silicon dioxide; microwave radiation; neutron; Mass Spectrometry; Microwaves; Neutrons; Nitric Acid; Polytetrafluoroethylene; Quartz; Trace Elements

Novel ethyl-derivatization approach for the determination of fluoride by headspace gas chromatography/mass spectrometry - Pagliano, Enea; Meija, Juris; Ding, Jianfu; Sturgeon, Ralph E.; D'Ulivo, Alessandro; Mester, Zoltán (Analytical Chemistry, 2012)
We report a novel derivatization chemistry for determination of fluoride based on the batch reaction of fluoride ions with triethyloxonium tetrachloroferrate(III) in a closed vessel to yield fluoroethane. Gaseous fluoroethane was readily separated from the matrix, sampled from the headspace, and determined by gas chromatography/mass spectrometry. The method was validated using rainwater certified reference material (IRMM CA408) and subsequently applied to the determination of fluoride in various matrixes, including tap water, seawater, and urine. An instrumental limit of detection of 3.2 μg/L with a linear range up to 50 mg/L was achieved. The proposed derivatization is a one-step reaction, requires no organic solvents, and is safe, as the derivatizing agent is nonvolatile. Determination of fluoride is affected by common fluoride-complexing agents, such as Al(III) and Fe(III). The effect of large amounts of these interferences was studied, and the adverse effect of these ions was eliminated by use of the method of standard additions.
Keywords: Adverse effect; Batch reactions; Certified reference materials; Closed vessels; Derivatizations; Fluoride ion; Gas chromatography/Mass spectrometry; Headspace gas chromatography; Headspaces; Limit of detection; Linear range; Non-volatile; One-step reactions; Standard addition; Tap water; Tetrachloroferrate; Chromatography; Iron compounds; Organic solvents; Seawater; Spectrometry

Guest editorial: medical near infrared spectroscopy 35 years after the discovery - Ferrari, Marco; Norris, Karl H.; Sowa, Michael G. (Journal of Near Infrared Spectroscopy, 2012)

New radio observations of the Moon at L band - Zhang, Xi-Zheng; Gray, Andrew; Su, Yan; Li, Jun-Duo; Landecker, Tom; Zhang, Hong-Bo; Li, Chun-Lai (Research in Astronomy and Astrophysics, 2012)
We present results of new radio observations of the Moon at L band with the synthesis telescope of the Dominion Radio Astrophysical Observatory Synthesis Telescope. The resolution and temperature sensitivity of the observations are 159″ × 87″ and 1.7K, respectively. The main results are: (1) the lunar brightness temperature averaged over the whole disk is about 233 K while the average brightness temperature for the four quadrants are 228.1K (NE), 239.7K (NW), 233.9K (SW) and 228.8K (SE). The observations reveal large temperature and spatial variations on the Moon for the first time. The highest brightness temperature is about 257 K and it is located along the lunar equator, to the west. The total uncertainty is about 5% due to the absolute accuracy of the fluxes of the primary calibrators; (2) the total degree of polarization is about 6%. Both polarization intensity and degree of polarization increase from the disk's center to the limb, and the distribution of the degree of polarization along the limb is not uniform; (3) the new data are used to study the properties of regolith, such as dielectric constant and thickness distribution. The results show that the lunar regolith's thickness increases from the NW (mare area) to the SE (highland area) regions on the lunar surface.

SSOS: A moving-object image search tool for asteroid precovery - Gwyn, Stephen D. J.; Hill, Norman; Kavelaars, J. J. (Publications of the Astronomical Society of the Pacific, 2012)
It is very difficult to find archival images of solar system objects. While regular archive searches can find images at a fixed location, they cannot find images of moving targets. Archival images have become increasingly useful to extragalactic and stellar astronomers the last few years, but until now, solar system researchers have been at a disadvantage in this respect. The Solar System Object Search (SSOS) at the Canadian Astronomy Data Centre allows users to search for images of moving objects. SSOS accepts as input either a list of observations, an object designation, a set of orbital elements, or a user-generated ephemeris for an object. It then searches for images containing that object over a range of dates. The user is then presented with a list of images containing that object from a variety of archives. Initially created to search the CFHT MegaCam archive, SSOS has been extended to other telescope archives, including Gemini, Subaru/SuprimeCam, HST, several ESO instruments, and the SDSS, for a total of 6.5 million images.

Observations, analysis, and spectroscopic classification of HO piscium: a bright shallow-contact binary with G- and M-type components - Samec, Ronald G.; Smith, Paul M.; Robb, Russell; Faulkner, Danny R.; Van Hamme, W. (Publications of the Astronomical Society of the Pacific, 2012)
We present a spectrum and a photometric analysis of the newly discovered, high-amplitude, solartype, eclipsing binary HO Piscium. A spectroscopic identification, a period study, q-search, and a simultaneous UBVR cI c light-curve solution are presented. The spectra and our photometric solution indicate that HO Psc is a W-typeWUMa shallow-contact (fill-out ~8%) binary system. The primary component has a G6V spectral type with an apparently precontact spectral type of M2V for the secondary component. The small fill-out indicates that the system has not yet achieved thermal contact and thus has recently come into physical contact. This may mean that this solar-type binary system has not attained its ~0:4 mass ratio via a long period of magnetic braking, as would normally be assumed.

Probing the mass assembly of massive nearby galaxies with deep imaging - Duc, P.-A.; Cuillandre, J.-C.; Alatalo, K.; Blitz, L.; Bois, M.; Bournaud, F.; Bureau, M.; Cappellari, M.; Côté, P.; Davies, R. L.; Davis, T. A.; De Zeeuw, P. T.; et al. (The intriguing life of massive galaxies, 2012)
According to a popular scenario supported by numerical models, the mass assembly and growth of massive galaxies, in particular the Early-Type Galaxies (ETGs), is, below a redshift of 1, mainly due to the accretion of multiple gas-poor satellites. In order to get observational evidence of the role played by minor dry mergers, we are obtaining extremely deep optical images of a complete volume limited sample of nearby ETGs. These observations, done with the CFHT as part of the ATLAS3D, NGVS and MATLAS projects, reach a stunning 28.5 - 29 mag.arcsec-2 surface brightness limit in the g' band. They allow us to detect the relics of past collisions such as faint stellar tidal tails as well as the very extended stellar halos which keep the memory of the last episodes of galactic accretion. Images and preliminary results from this on-going survey are presented, in particular a possible correlation between the fine structure index (which parametrizes the amount of tidal perturbation) of the ETGs, their stellar mass, effective radius and gas content.

Behaviour of fibre reinforced polymer-strengthened T-beams and slabs in fire - Adelzadeh, Masoud; Green, Mark F.; Bénichou, Noureddine (Proceedings of the Institution of Civil Engineers: Structures and Buildings, 2012)
This paper presents experimental and numerical results of intermediate-scale and full-scale fire tests conducted on flexurally strengthened reinforced concrete members. Two full-scale reinforced concrete T-beams and two intermediate-scale slabs were strengthened in flexure with carbon fibre reinforced polymer sheets or plates and insulated with a layer of spray-on material. T-beams and slabs were then exposed to a standard fire. T-beams were loaded to their service load. Deflections and temperatures were measured during the tests. A numerical finite-difference/volume heat transfer model was used to simulate the temperature field inside the section. The validity of the numerical model was verified by comparing the predicted temperatures with those recorded during the fire test. Fire test results show that fire endurances of more than 4 h can be achieved using an appropriate insulation system.
Keywords: Carbon fibre reinforced polymer; Fibre reinforced; Finite difference; Fire endurances; Fire engineering; Fire tests; Heat transfer model; Insulation system; Numerical results; Reinforced concrete member; Service loads; Standard fire; T beams; Carbon fibers; Concrete construction; Fiber reinforced plastics; Patient rehabilitation; Reinforced concrete; Flammability testing; concrete structure; experimental study; finite difference method; fire behavior; heat transfer; high temperature; insulation; numerical model; polymer; reinforced concrete; structural component; temperature effect

Hydrodynamic impacts of tidal power lagoons in the Bay of Fundy - Cousineau, Julien; Nistor, Ioan; Cornett, Andrew (Proceedings of the 33rd International Conference on Coastal Engineering 2012, 2012)
The Bay of Fundy (BoF) in eastern Canada has long been recognised as one of the world's premier locations for the development of tidal power generating systems, since it has some of the world's largest tidal ranges. Several proposals have been made in recent years to find economical ways to harness the power of these extremely high tides, including constructing one or more tidal power lagoons in the upper part of the Bay. The tidal power lagoon concept involves temporarily storing seawater behind an impoundment dike and generating power by gradually releasing the impounded seawater through conventional low-head hydroelectric turbines. A tidal power lagoon will inherently modify the tides and tidal currents in the vicinity of the lagoon, and possibly induce effects that may be felt throughout the entire BoF and Gulf of Maine. The nature of these hydrodynamic impacts will likely depend on the size of the tidal lagoon, its location, and its method of operation. It is important to have reliable estimates of these potential impacts, since any changes in tidal hydrodynamics caused by a tidal lagoon may upset ecosystems that are well adapted to existing conditions. The scale and character of the potential hydrodynamic impacts due to tidal power lagoons operating in the BoF have not been previously investigated. This paper presents the results of study in which a 2D (depth-averaged) hydrodynamic model based on the TELEMAC modelling system was developed and applied to analyze, predict, and quantify the potential changes in tidal hydrodynamics (water levels, tidal range, circulation patterns and tidal currents) throughout the Bay of Fundy and Gulf of Maine due to the presence of a single tidal lagoon and multiple lagoons operating at various locations in the upper BoF. The sensitivity to changes in lagoon type, size, location, the number of lagoons, and their operating mode was also investigated and established. The final purpose of this novel study is to assist with decisions concerning the development of the vast tidal energy resources available in the Bay of Fundy, Canada.
Keywords: Bay of Fundy; Circulation patterns; Hydrodynamic impacts; Hydrodynamic model; Power generating systems; Reliable estimates; Renewable energies; Tidal lagoon; Coastal engineering; Energy resources; Hydraulic structures; Hydrodynamics; Numerical models; Ocean currents; Seawater; Tidal power; Tides; Water levels; Lakes

A critical evaluation of turbulence modeling in a model combustor - Jiang, Leiyong (Proceedings of the ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. Volume 1: Aircraft Engine; Ceramics; Coal, Biomass and Alternative Fuels; Controls, Diagnostics and Instrumentation, 2012)
Based on the previous benchmark studies on combustion, scalar transfer and radiation models, a critical evaluation of turbulence models in a propane-air diffusion flame combustor with interior and exterior conjugate heat transfers has been performed. Results obtained from six turbulence models are presented and compared in detail with a comprehensive database obtained from a series of experimental measurements. It is found that the Reynolds stress model (RSM), a second moment closure, is superior over the five popular eddy-viscosity two-equation models. Although the main flow patterns are captured by all six turbulence models, only the RSM is able to successfully predict the lengths of both recirculation zones and give fairly accurate predictions for mean velocity, temperature, CO2 and CO mole fractions, as well as turbulence kinetic energy in the combustor chamber. In addition, the realizable k-ε (Rk-ε) model illustrates better performance than four other two-equation models and can provide comparable results to those from the RSM for the configuration and operating conditions considered in the present study. Copyright © 2012 by ASME.
Keywords: Accurate prediction; Conjugate heat transfer; Critical evaluation; Diffusion flame combustors; Operating condition; Reynolds stress models; Second-moment closures; Turbulence kinetic energy; Exhibitions; Gas turbines; Kinetics; Turbulence models; Combustors

Effects of scalloping on the mixing mechanisms of forced mixers with highly swirling core flow - Wright, Alex; Lei, Zhijun; Mahallati, Ali; Cunningham, Mark; Militzer, Julio (Proceedings of the ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. Volume 1: Aircraft Engine; Ceramics; Coal, Biomass and Alternative Fuels; Controls, Diagnostics and Instrumentation, 2012)
This paper presents a detailed experimental and computational investigation of the effects of scalloping on the mixing mechanisms of a scaled 12-lobe turbofan mixer. Scalloping was achieved by eliminating approximately 70% of the lobe sidewall area. Measurements were made downstream of the mixer in a co-annular wind tunnel and the simulations were carried out using an unstructured RANS solver, Numeca FINE/Hexa, with k-ω SST model. In the core flow, the swirl angle was varied from 0° to 30°. At high swirl angles, a three-dimensional separation bubble was formed on the lobe's suction surface penetration region and resulted in the generation of a vortex at the lobe valley. The valley vortex quickly dissipated downstream. Most of the swirl was removed by the lobes, but scalloping allowed residual swirl to persist downstream of the mixer. The interaction of the swirling flow and the vortices resulted in improved mixing rates for the scalloped mixer. Inlet swirl up to 10° provided improved mixing rates, reduced pressure loss and thrust loss for both mixers. High inlet swirl resulted in improved mixing but produced higher pressure and thrust losses as compared to the zero swirl case. At high swirl, the scalloped mixer resulted in better mixing and lower pressure losses than the unscalloped mixer, but at the expense of reduced thrust.
Keywords: Computational investigation; Inlet swirls; Lower pressures; Mixing mechanisms; Reduced pressure; Separation bubble; Suction surfaces; Swirl angles; Computer simulation; Exhibitions; Gas turbines; Mixing; Molluscs; Vortex flow; Mixers (machinery)

Tribological behaviours of titanium nitride and chromium nitride based PVD coating systems - Cai, F.; Huang, Xiao; Yang, Q.; Nagy, Doug (Proceedings of the ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. Volume 5: Manufacturing Materials and Metallurgy; Marine; Microturbines and Small Turbomachinery; Supercritical CO2 Power Cycles, 2012)
This study investigates the effects of the deposition process and coating composition on microstructural and tribological properties of TiN and CrN based coating systems. Coatings were produced using various PVD based processes - electron beam (EB), cathodic arc (CA) and plasma enhanced magnetron sputtering (PEMS). All coated samples were evaluated for their composition, microstructure and surface morphology. Coating mechanical properties such as hardness, Young's modulus and coefficient of friction were also studied and related to their microstructures, wear and erosion resistances. It was found that hardness (H), Young's modulus (E) and coefficient of friction had impact on both wear and erosion rates. In particular, the H3/E2 ratio was inversely proportional to the specific wear rate. For erosion behaviour, higher H3/E2 ratios relate to lower erosion rates at low impingement angles; whereas higher H3/E2 ratios relate to higher erosion rates at high impingement angles.
Keywords: Coating compositions; Coefficient of frictions; CrN-based coatings; Erosion resistance; Plasma enhanced magnetron sputtering; Specific wear rates; Tribological behaviour; Tribological properties; Amorphous films; Elastic moduli; Exhibitions; Friction; Gas turbines; Hardness; Microstructure; Protective coatings; Titanium nitride; Tribology; Erosion

On advanced estimation techniques for exoplanet detection and characterization using ground-based coronagraphs - Lawson, Peter R.; Poyneer, Lisa; Barrett, Harrison; Frazin, Richard; Caucci, Luca; Devaney, Nicholas; Furenlid, Lars; Gładysz, Szymon; Guyon, Olivier; Krist, John; Maire, Jérôme; Marois, Christian; et al. (Adaptive Optics Systems III, 2012)
The direct imaging of planets around nearby stars is exceedingly difficult. Only about 14 exoplanets have been imaged to date that have masses less than 13 times that of Jupiter. The next generation of planet-finding coronagraphs, including VLT-SPHERE, the Gemini Planet Imager, Palomar P1640, and Subaru HiCIAO have predicted contrast performance of roughly a thousand times less than would be needed to detect Earth-like planets. In this paper we review the state of the art in exoplanet imaging, most notably the method of Locally Optimized Combination of Images (LOCI), and we investigate the potential of improving the detectability of faint exoplanets through the use of advanced statistical methods based on the concepts of the ideal observer and the Hotelling observer. We propose a formal comparison of techniques using a blind data challenge with an evaluation of performance using the Receiver Operating Characteristic (ROC) and Localization ROC (LROC) curves. We place particular emphasis on the understanding and modeling of realistic sources of measurement noise in ground-based AO-corrected coronagraphs. The work reported in this paper is the result of interactions between the co-authors during a week-long workshop on exoplanet imaging that was held in Squaw Valley, California, in March of 2012.
Keywords: Coronagraphs; Data challenges; Detectability; Direct imaging; Earth-like planets; Estimation techniques; Exo-planets; Ground based; Hotelling observers; Ideal observers; Instrumentation; Jupiters; Localization rocs; Measurement Noise; Receiver operating characteristics; State of the art; Adaptive optics; Planets

Final opto-mechanical design of Raven, a MOAO science demonstrator for Subaru - Lardière, Olivier; Nash, Reston; Markes, J.-P.; Andersen, Dave; Bradley, Colin; Blain, Célia; Desmarais, Ronald; Gamroth, Darryl; Ito, Meguru; Jackson, Kate; Lach, Przemek; Pham, Laurie (Adaptive Optics Systems III, 2012)
Raven is a Multi-Object Adaptive Optics (MOAO) technical and scientific demonstrator which will be used on the Subaru telescope with the IRCS spectrograph. The optical and mechanical designs are finalised and the system is now being integrated in the lab at UVic. Raven features three open-loop wavefront sensors (WFS) patrolling a 3.5' field of regard, one on-axis LGS WFS, two science channels each equipped with a pick-off arm, an 11x11 actuator deformable mirror, a closed-loop WFS for calibration and performance comparison and an image rotator. This paper presents in detail the optical design and its performance, as well as the mechanical design.
Keywords: Closed-loop; Deformable mirrors; Field of regard; Image rotator; Mechanical design; Multiobject; On-sky demonstrator; Opto-mechanical design; Performance comparison; Pick-off; Subaru telescopes; Wave front sensors; Adaptive optics; Analog differential analyzers; Optical design; Electric appliances

SPIRou @ CFHT: spectrograph optical design - Thibault, Simon; Rabou, Patrick; Donati, Jean-Francois; Desaulniers, Pierre; Dallaire, Xavier; Artigau, Etienne; Pepe, Francesco; Micheau, Yoan; Vallée, Philippe; Barrick, Greg; Reshetov, Vlad; Hernandez, Olivier; et al. (Ground-based and Airborne Instrumentation for Astronomy IV, 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 (eight) papers at this conference. In this paper we focus on the lens design of the optical spectrograph. The SPIROU spectrograph is a near infrared fiber fed double pass cross dispersed spectrograph. The cryogenic spectrograph is connected with the Cassegrain unit by the two science fibers. It is also fed by the fiber coming from the calibration box and RV reference module of the instrument. It includes 2 off-axis parabolas (1 in double pass), an echelle grating, a train of cross disperser prisms (in double pass), a flat folding mirror, a refractive camera and a detector. This paper describes the optical design of the spectrograph unit and estimates the performances. In particular, the echelle grating options are discussed as the goal grating is not available from the market. © 2012 SPIE.
Keywords: CFHT; Echelle gratings; High precision; Near-IR; Spectropolarimetry; Astronomy; Cryogenics; Diffraction gratings; Infrared devices; Instruments; Spectrographs

Introduction to the CFHT Legacy Survey final release (CFHTLS T0007) - Cuillandre, Jean-Charles; Withington, Kanoa; Hudelot, Patrick; Goranova, Yuliana; McCracken, Henry; Magnard, Frédéric; Mellier, Yannick; Regnault, Nicolas; Bétoule, Marc; Aussel, Hervé; Kavelaars, J. J.; Fernique, Pierre; et al. (Observatory Operations: Strategies, Processes, and Systems IV, 2012)
The Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) is a high impact scientific program which will see its final official release open to the world in 2012. That release will seal the legacy aspect of the survey which has already produced a large collection of scientific articles with topics ranging from cosmology to the Solar system. The survey core science was focused on dark energy and dark matter: the full realization of the scientific potential of the data set gathered between 2003 and 2009 with the MegaCam wide-field imager mounted at the CFHT prime focus is almost complete with the Supernovae Legacy Survey (SNLS) team preparing its third and last release (SNLS5), and the CFHTLenS team planning the release based around the cosmic shear survey later this year. While the data processing center TERAPIX offered to the CFHTLS scientific community regular releases over the course of the survey in its data acquisition phase (T0001-T0006), the final release took three years to refine in order to produce a pristine data collection photometrically calibrated at better than the percent both internally and externally over the total survey surface of 155 square degrees in all five photometric bands (u*, g', r', i', z'). This final release, called T0007, benefits from the various advances in photometric calibration MegaCam has benefited through the joint effort between SNLS and CFHT to calibrate MegaCam at levels unexplored for an optical wide-field imager. T0007 stacks and catalogs produced by TERAPIX will be made available to the world at CADC while the CDS will offer a full integration of the release in its VO tools from VizieR to Aladin. The photometric redshifts have been produced to be released in phase with the survey. This proceeding is a general introduction to the survey and aims at presenting its final release in broad terms.
Keywords: CdS; Cosmic shear; Curation; Dark energy; Dark matter; Data collection; Data sets; Full integration; High impact; In-phase; Optical; Photometric calibration; Prime-focus; Processing center; Red shift; Team planning; Virtual observatory; Wide-field imager; Buildings; Calibration; Data acquisition; Observatories; Photometry; Solar system; Surveys

Woofer-tweeter adaptive optics in very strong turbulence using a magnetic-liquid deformable mirror - Brousseau, Denis; Véran, Jean-Pierre; Thibault, Simon; Borra, Ermanno F.; F.-Boivin, Simon (Adaptive Optics Systems III, 2012)
We present progress towards the development of a woofer-tweeter adaptive optics (AO) system using the first 37 actuators of a 91-actuator magnetic-liquid deformable mirror (MLDM) and a magnetic 97-actuator DM from ALPAO. The MLDM, which has both very large single-actuator and inter-actuator strokes, but a low bandwidth, is used as woofer, whereas the high bandwidth and lower stroke ALPAO DM is used as tweeter. The ALPAO DM should improve the bandwidth of the MLDM while the MLDM will allow correction of strong aberrations.
Keywords: Adaptive optics systems; Deformable mirrors; High bandwidth; Low-bandwidth; Strong turbulence; Actuators; Adaptive optics; Bandwidth; Laser pulses; Loudspeakers; Liquids

Review of small-angle coronagraphic techniques in the wake of ground-based second-generation adaptive optics systems - Mawet, Dimitri; Pueyo, Laurent; Lawson, Peter; Mugnier, Laurent; Traub, Wesley; Boccaletti, Anthony; Trauger, John T.; Gladysz, Szymon; Serabyn, Eugene; Milli, Julien; Belikov, Ruslan; Kasper, Markus; et al. (Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, 2012)
Small-angle coronagraphy is technically and scientifically appealing because it enables the use of smaller telescopes, allows covering wider wavelength ranges, and potentially increases the yield and completeness of circumstellar environment - exoplanets and disks - detection and characterization campaigns. However, opening up this new parameter space is challenging. Here we will review the four posts of high contrast imaging and their intricate interactions at very small angles (within the first 4 resolution elements from the star). The four posts are: choice of coronagraph, optimized wavefront control, observing strategy, and post-processing methods. After detailing each of the four foundations, we will present the lessons learned from the 10+ years of operations of zeroth and first-generation adaptive optics systems. We will then tentatively show how informative the current integration of second-generation adaptive optics system is, and which lessons can already be drawn from this fresh experience. Then, we will review the current state of the art, by presenting world record contrasts obtained in the framework of technological demonstrations for space-based exoplanet imaging and characterization mission concepts. Finally, we will conclude by emphasizing the importance of the cross-breeding between techniques developed for both ground-based and space-based projects, which is relevant for future high contrast imaging instruments and facilities in space or on the ground.
Keywords: Coronagraphy; High contrast imaging; Observing strategy; Post processing; Working angle; Instruments; Millimeter waves; Space telescopes; Adaptive optics

High-contrast imaging in the Hyades with snapshot LOCI - Morzinski, Katie M.; Macintosh, Bruce A.; Close, Laird M.; Marois, Christian; Konopacky, Quinn; Patience, Jenny (Adaptive Optics Systems III, 2012)
To image faint substellar companions obscured by the stellar halo and speckles, scattered light from the bright primary star must be removed in hardware or software. We apply the "locally-optimized combination of images" (LOCI) algorithm to 1-minute Keck Observatory snapshots of GKM dwarfs in the Hyades using source diversity to determine the most likely PSF. We obtain a mean contrast of 10-2 at 0.″01, 10-4 at <1″, and 10-5 at 5″. New brown dwarf and low-mass stellar companions to Hyades primaries are found in a third of the 84 targeted systems. This campaign shows the efficacy of LOCI on snapshot imaging as well as on bright wide binaries with off-axis LOCI, reaching contrasts sufficient for imaging 625-Myr late-L/early-T dwarfs purely in post-processing.
Keywords: Brown dwarfs; High contrast imaging; Hyades; Image diversity; LOCI; PSF; Adaptive optics; Stars; Image processing

Ultra violet imaging telescope (UVIT) on ASTROSAT - Kumar, Amit; Ghosh, S. K.; Hutchings, J.; Kamath, P. U.; Kathiravan, S.; Mahesh, P. K.; Murthy, J.; Nagbhushana, S.; Pati, A. K.; Rao, M. N.; Rao, N. K.; Sriram, S.; et al. (Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray, 2012)
The Ultra Violet Imaging Telescope on ASTROSAT Satellite mission is a suite of Far Ultra Violet (FUV: 130 - 180 nm), Near Ultra Violet (NUV: 200 - 300 nm) and Visible band (VIS: 320-550nm) imagers. ASTROSAT is the multiwavelength mission of ISRO. UVIT will image the sky simultaneously in three channels with a field of view diameter of ̃ 28 arcminutes and an angular resolution < 1.8". Two identical co-Aligned telescopes (T1, T2) of Ritchey-Chretien configuration (Primary mirror of ̃375 mm diameter) collect the celestial radiation and feed the detector systems via a selectable filter on a filter wheel mechanism; gratings are available in the filter wheels of FUV and NUV channels for slitless low-resolution spectroscopy. The photon-counting detector system for each of the 3 channels is generically identical. one of the telescopes images in the FUV channel, while the other images in NUV and VIS channels via a beamsplitter. Images from the VIS channel are principally used for measuring drift, used in construction of images on the ground by shift and add, and to reconstruct absolute aspect of the images. Adequate baffling has been provided for reducing the scattered background from the Sun, earth albedo and other bright objects. The one-Time opening mechanical cover on each telescope also works as a Sun-shield after deployment. We will present the overall (mechanical, optical and electrical) design of the payload. © 2012 SPIE.
Keywords: Angular resolution; CMOS STAR250; Detector systems; Earth albedo; Field of views; Filter wheel; Multiwavelength; Photon counting; Primary mirrors; Satellite mission; Shift-and-add; Sun-shield; Three channel; UV; Visible band; Detectors; Gamma rays; Space telescopes; Optical telescopes

SPICES: a 1.5-m space coronagraph for spectro-polarimetric characterization of cold exoplanets - Maire, Anne-Lise; Boccaletti, Anthony; Schneider, Jean; Galicher, Raphaël; Baudoz, Pierre; Stam, Daphne; Traub, Wesley; Lagage, Pierre-Olivier; Gratton, Raffaele (Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, 2012)
The study of the physico-chemical properties of wide-separated exoplanets (> 1 AU) is a major goal of highcontrast imaging techniques. SPICES (Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems) is a project of space coronagraph dedicated to the spectro-polarimetric analysis of gas and ice giant planets, super-Earths and circumstellar disks in visible light at a spectral resolution of about 40. After recalling the science cases of the mission, we describe the optical design and the critical subsystems of the instrument. We then discuss the SPICES performance that we derived from numerical simulations.
Keywords: Circumstellar disks; Exo-planets; High angular resolutions; High contrast imaging; Ice giants; Integral field; Physicochemical property; Visible light; Chemical properties; Imaging techniques; Instruments; Millimeter waves; Optical design; Polarimeters; Space telescopes; Food products

SPIRou @CFHT: design of the instrument control system - Barrick, Gregory A.; Vermuelen, Tom; Baratchart, Sébastien; Reshetov, Vladimir A.; Wang, Shiang-Yu; Dolon, François; Hernandez, Olivier; Pepe, Francesco; Bouchy, François; Dunn, Jennifer; Dupieux, Michel; Gallou, Gérard; et al. (Software and Cyberinfrastructure for Astronomy II, 2012)
SPIRou is a near-IR (0.98-2.35μm), echelle spectropolarimeter / high precision velocimeter being designed as a next-generation instrument for the 3.6m Canada-France-Hawaii Telescope on Mauna Kea, Hawaii, with the main goals of detecting Earth-like planets around low-mass stars and magnetic fields of forming stars. The unique scientific and technical capabilities of SPIRou are described in a series of eight companion papers. In this paper, the means of controlling the instrument are discussed. Most of the instrument control is fairly normal, using off-the-shelf components where possible and reusing already available code for these components. Some aspects, however, are more challenging. In particular, the paper will focus on the challenges of doing fast (50 Hz) guiding with 30 mas repeatability using the object being observed as a reference and on thermally stabilizing a large optical bench to a very high precision (∼1 mK).
Keywords: CFHT; Control-command; Fast guiding; High precision; Near-IR; Spectropolarimetry; Thermal control; Tip-tilt; Algorithms; Stars; Velocity measurement; Velocimeters

TMT NFIRAOS: adaptive optics for the Thirty Meter Telescope - Herriot, Glen; Andersen, David; Atwood, Jenny; Byrnes, Peter; Boucher, Marc-André; Boyer, Corinne; Caputa, Kris; Correia, Carlos; Dunn, Jennifer; Ellerbroek, Brent; Fitzsimmons, Joeleff; Gilles, Luc; et al. (Adaptive Optics Systems III, 2012)
NFIRAOS is the first-light adaptive optics system planned for the Thirty Meter Telescope, and is being designed at the National Research Council of Canada's Herzberg Institute of Astrophysics. NFIRAOS is a laser guide star multi-conjugate adaptive optics system - a practical approach to providing diffraction limited image quality in the NIR over a 30" field of view, with high sky coverage. This will enable a wide range of TMT science that depends upon the large corrected field of view and high precision astrometry and photometry. We review recent progress developing the design and conducting performance estimates for NFIRAOS.
Keywords: Conducting performance; Diffraction limited; Field of views; First-light adaptive optics system; High precision; Laser guide star; Multi-conjugate adaptive optics systems; NFIRAOS; Sky coverage; Optical telescopes

Tip/Tilt point spread function reconstruction for laser guide star multi conjugate adaptive optics - Gilles, L.; Correia, C.; Véran, J.P.; Wang, L.; Ellerbroek, B. L. (Adaptive Optics Systems III, 2012)
In adaptive optics systems employing laser guide stars, the tip/tilt contribution to the long exposure point spread function must be estimated separately from the high-order tip/tilt removed point spread function because this component is estimated separately from a single or multiple low-order natural guide star wavefront sensors. This paper investigates this problem for laser guide star multi conjugate adaptive optics. The approach is based on the scheme developed by Flicker in 2003 [1], and consists in post-processing the measurement covariance matrix of multiple low-order natural guide star wavefront sensors controlling tip/tilt and tilt anisoplanatism. An innovative simulation model based "balanced" algorithm is introduced to capture error terms not accounted for in Flicker's algorithm. Sample enclosed energy results for the Thirty Meter Telescope multi conjugate adaptive optics system demonstrate the superiority of the balanced method and call for further analytical work and experimental validation.
Keywords: Anisoplanatism; Capture error; Experimental validations; High-order; Multi-conjugate adaptive optics systems; Natural guide star; Point spread function reconstruction; Post processing; Simulation model; Thirty Meter Telescope; Wave front sensors; Algorithms; Atmospheric turbulence; Computer simulation; Covariance matrix; Lasers; Optical transfer function; Sensors; Stars; Wavefronts

Status of the Raven MOAO science demonstrator - Andersen, David R.; Bradley, C.; Lardière, O.; Blain, C.; Correia, C.; Desmarais, R.; Gamroth, D.; Ito, M.; Jackson, K.; Lach, P.; Nash, R.; Pham, L.; et al. (Adaptive Optics Systems III, 2012)
Raven is a Multi-Object Adaptive Optics (MOAO) scientific demonstrator which will be used on-sky at the Subaru observatory. Raven is currently being built at the University of Victoria AO Lab. In this paper, we present an overview of the final Raven design and then describe lab tests involving prototypes of Raven subsystems. The final design includes three open loop wavefront sensors (WFSs), a laser guide star WFS and two figure/truth WFSs. Two science channels, each containing a deformable mirror (DM), feed light to the Subaru IRCS spectrograph. Central to the Raven MOAO system is a Calibration Unit (CU) which contains multiple sources, a telescope simulator including two rotating phase screens and a ground layer DM that can be used to calibrate and test Raven. We are working with the Raven CU and open loop WFSs to test and validate our open loop calibration and alignment techniques.
Keywords: Alignment technique; Calibration unit; Deformable mirrors; Ground layer; Laser guide star; Multiobject; Multiple source; Phase screen; Wave front sensors; Calibration; Electric appliances; Adaptive optics

The Gemini Planet Imager: integration and test - Macintosh, Bruce A.; Anthony, Andre; Atwood, Jennifer; Barriga, Nicolas; Bauman, Brian; Caputa, Kris; Chilcote, Jeffery; Dillon, Daren; Doyon, René; Dunn, Jennifer; Gavel, Donald T.; Galvez, Ramon; et al. (Ground-based and Airborne Instrumentation for Astronomy IV, 2012)
The Gemini Planet Imager is a next-generation instrument for the direct detection and characterization of young warm exoplanets, designed to be an order of magnitude more sensitive than existing facilities. It combines a 1700-actuator adaptive optics system, an apodized-pupil Lyot coronagraph, a precision interferometric infrared wavefront sensor, and a integral field spectrograph. All hardware and software subsystems are now complete and undergoing integration and test at UC Santa Cruz. We will present test results on each subsystem and the results of end-to-end testing. In laboratory testing, GPI has achieved a raw contrast (without post-processing) of 10-6 5σ at 0.4'', and with multiwavelength speckle suppression, 2x10^-7 at the same separation.
Keywords: Adaptive optics systems; Coronagraphy; Direct detection; Exo-planets; Extra solar planets; Hardware and software; Integral field spectrograph; Laboratory testing; Lyot coronagraphs; Multiwavelength; Post processing; Speckle suppression; Wave front sensors; Adaptive optics; Astronomy; Instruments; Software testing

Atmospheric characterization of cold exoplanets with a 1.5-m space coronagraph - Maire, Anne-Lise; Galicher, Raphaël; Boccaletti, Anthony; Baudoz, Pierre; Schneider, Jean; Cahoy, Kerri; Stam, Daphne; Traub, Wesley (Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, 2012)
Several small space coronagraphs have been proposed to characterize cold exoplanets in reected light. Studies have mainly focused on technical feasibility because of the huge star/planet ux ratio to achieve in the close-in stellar environment (108-1010 at 0.2). However, the main interest of such instruments, the analysis of planet properties, has remained highly unexplored so far. We performed numerical simulations to assess the ability of a small space coronagraph to retrieve spectra of mature Jupiters, Neptunes and super-Earths under realistic assumptions. We describe our assumptions: exoplanetary atmosphere models, instrument numerical simulation and observing conditions. Then, we define a criterion and use it to determine the required exposure times to measure several planet parameters from their spectra (separation, metallicity, cloud and surface coverages) for particular cases. Finally, we attempt to define a parameter space of the potential targets. In the case of a solar-type star, we show that a small coronagraph can characterize the spectral properties of a 2-AU Jupiter up to 10 pc and the cloud and surface coverage of super-Earths in the habitable zone for a few stars within 4{5 pc. Potentially, SPICES could perform analysis of a hypothetical Earth-size planet around α Cen A and B.
Keywords: Atmosphere models; Atmospheric characterization; Exo-planets; High angular resolutions; High contrast imaging; Integral field; Jupiters; Metallicities; Parameter spaces; Potential targets; Solar type stars; Spectral properties; Surface coverages; Technical feasibility; Computer simulation; Imaging techniques; Instruments; Millimeter waves; Space telescopes; Stars; Earth (planet)

SPIRou @CFHT: Fiber links and pupil slicer - Micheau, Yoan; Bouchy, François; Pepe, Francesco; Chazelas, Bruno; Kouach, Driss; Parès, Laurent; Donati, Jean-François; Barrick, Gregory; Rabou, Patrick; Thibault, Simon; Saddlemyer, Leslie; Perruchot, Sandrine; et al. (Ground-based and Airborne Instrumentation for Astronomy IV, 2012)
SPIRou is a near-IR (0.98-2.35μm), echelle spectropolarimeter / high precision velocimeter being designed as a next-generation instrument for the 3.6m Canada-France-Hawaii Telescope on Mauna Kea, Hawaii, with the main goal of detecting Earth-like planets around low mass stars and magnetic fields of forming stars. The unique scientific and technical capabilities of SPIRou are described in a series of seven companion papers. In this paper, the fiber links which connects the polarimeter unit to the cryogenic spectrograph unit (35 meter apart) are described. The pupil slicer which forms a slit compatible with the spectrograph entrance specifications is also discussed in this paper. Some challenging aspects are presented. In particular this paper will focus on the manufacturing of 35 meter fibers with a very low loss attenuation (< 13dB/km) in the non-usual fiber spectral domain from 0.98 μm to 2.35 μm. Other aspects as the scrambling performance of the fiber links to reach high accuracy radial velocity measurements (1m/s) and the design of the pupil slicer exposed at a cryogenic and vacuum environment will be discussed.
Keywords: CFHT; Fluoride fibers; FRD; High precision; Pupil slicer; Scrambling; Spectropolarimetry; Cryogenics; Spectrographs; Stars; Velocimeters; Velocity measurement; Fibers

'Imaka: working towards very wide-field of view AO - Chun, M.; Lai, O.; Cuillandre, J.-C.; Richer, H.; Toomey, D.; Salmon, D.; Carlberg, R.; Andersen, D.; Burgarella, D.; Ho, K.; Pazder, J.; Bertin, E. (Adaptive Optics Systems III, 2012)
Ground-layer adaptive optics (GLAO) has the potential to dramatically increase the efficiency and capabilities of existing ground-based telescopes over a broad range of astronomical science. Recent studies of the optical turbulence above several astronomical sites (e.g. Mauna Kea, Paranal, and Antarctica) show that GLAO can be extended to fields of view of several tens of arcminutes in diameter, larger than previously thought, with angular resolutions close to the free-atmosphere seeing. This is a pivotal result since GLAO science cases benefit from the largest possible corrected fields of view. The corrected areal field of a GLAO system is potentially 2-3 orders of magnitude larger than has been demonstrated to date. The 'Imaka team is working toward an instrument that takes advantage of the one-degree field afforded by Mauna Kea. In this paper we summarize the design/simulation work to date along with our plan to develop an instrument that reaches for this wide field of view. © 2012 SPIE.
Keywords: Angular resolution; Antarctica; Fields of views; Ground-based telescopes; Ground-layer adaptive optics; Optical turbulence; Orders of magnitude; Paranal; Wide field imaging; Wide field of view; Wide-field; Engineering; Molecular physics; Adaptive optics

TMT DMs final design and advanced prototyping results at Cilas - Sinquin, Jean-Christophe; Bastard, Arnaud; Boyer, Corinne; Cornette, Sébastien; Cousty, Raphaël; Ellerbroek, Brent; Gilbert, Xavier; Gourdet, Benoit; Grasser, Régis; Groeninck, Denis; Guillemard, Claude; Herriot, Glen; et al. (Adaptive Optics Systems III, 2012)
In order to prepare for the construction phase of the two Deformable Mirrors (DMs), which will be used in the Thirty Meter Telescope (TMT) first light Adaptive Optics (AO) system, Cilas has advanced the design of these two large size piezo DMs and has manufactured and tested a scaled demonstration prototype. The work done allowed significant reduction of the risks related to the demanding specifications of the TMT DMs; the main issues were: (i) Large pupil (up to 370 mm) and high order (up to 76x76); (ii) Relatively low operational temperature (DMs working at -30°C); (iii) New piezo material. It is important to develop such a prototype to take into account these three specifications all together (dimension, low temperature and new piezo material). The new prototype is a 6x60 actuators and has the same characteristics as the future TMT DMs. In this paper, we give the conclusions of the work through the presentation of the following items: (i) Design and finite element analysis of the two DMs and prototype; (ii) Test results obtained with the prototype with validation of the finite element analysis and compliance with the TMT AO specifications; (iii) Special focus on thermal behavior, actuator reliability and shape at rest stability. © 2012 SPIE.
Keywords: Adaptive optics systems; Construction phase; Deformable mirrors; Low temperatures; Operational temperature; Piezomaterials; Piezostack actuators; SAM; Thermal behaviors; Thirty Meter Telescope; Actuators; Adaptive optics; Finite element method; Laser pulses; Metal drawing; Specifications

Improved red sensitivity deep depletion e2v devices for the Gemini North GMOS instrument - Roth, Katherine C.; Kleinman, Scot J.; Chiboucas, Kristin; Schiavon, Ricardo; Hanna, Kevin; Rippa, Mathew; White, John K.; Walls, Brian; Yamasaki, Chris; Murowinski, Richard; Labrie, Kathleen; Gimeno, German; et al. (Ground-based and Airborne Instrumentation for Astronomy IV, 2012)
The GMOS-N instrument was upgraded with new CCDs in October 2011, improving the instrument sensitivity at both red and blue wavelengths. The deep depletion devices are manufactured by e2v (42-90 with multi-layer 3 coating) and extend the useful wavelength range of GMOS-N to 0.98 microns (compared to 0.94 microns previously). These detectors also exhibit much lower fringing than the original EEV detectors that had been in use since GMOS-N was commissioned in 2002. All other characteristics of the new detectors (readout speed, pixel size and format, detector controller, noise, gain) are similar to the original CCDs. Operating the new detectors in all amps mode (2 per CCD) has effectively improved the readout speed by a factor of 2. The new devices were selected to provide a quick and relatively simply upgrade route while technical issues with the Hamamatsu devices, originally planned for the upgrade, were investigated and resolved. We discuss the rationale for this interim upgrade, the upgrade process and attending issues. The new detectors have been used for science since November 2011. We present commissioning results illustrating the resulting gain in sensitivity over the original detector package. Gemini is still committed to installing Hamamatsu devices, which will further extend the useful wavelength range of GMOS to 1.03 microns, in both North and South GMOS instruments. We discuss the status of the Hamamatsu project and the current planned schedule for these future upgrades.
Keywords: Blue wavelength; CCDs; Deep depletion; e2v; GMOS; Hamamatsu; New detectors; Pixel size; Wavelength ranges

Test results for the Gemini Planet Imager data reduction pipeline - Maire, Jérôme; Perrin, Marshall D.; Doyon, René; Chilcote, Jeffrey; Larkin, James E.; Weiss, Jason L.; Marois, Christian; Konopacky, Quinn M.; Millar-Blanchaer, Maxwell; Graham, James R.; Dunn, Jennifer; Galicher, Raphael; et al. (Software and Cyberinfrastructure for Astronomy II, 2012)
The Gemini Planet Imager (GPI) is a new facility instrument for the Gemini Observatory designed to detect and characterize planets and debris disks orbiting nearby stars; its science camera is a near infrared integral field spectrograph. We have developed a data pipeline for this instrument, which will be made publicly available to the community. The GPI data reduction pipeline (DRP) incorporates all necessary image reduction and calibration steps for high contrast imaging in both the spectral and polarimetric modes, including datacube generation, wavelength solution, astrometric and photometric calibrations, and speckle suppression via ADI and SSDI algorithms. It is implemented in IDL as a flexible modular system, and includes both command line and graphical interface tools including a customized viewer for GPI datacubes. This GPI data reduction pipeline is currently working very well, and is in use daily processing data during the instrument's ongoing integration and test period at UC Santa Cruz. Here we summarize the results from recent pipeline tests, and present reductions of instrument test data taken with GPI. We will continue to refine and improve these tools throughout the rest of GPI's testing and commissioning, and they will be released to the community, including both IDL source code and compiled versions that can be used without an IDL license.
Keywords: Command line; Data cube; Debris disk; Exo-planets; Flexible modular; High contrast imaging; Image reduction; Integral field spectrograph; Near Infrared; Photometric calibration; Pipeline tests; Source codes; Speckle suppression; Calibration; Data processing; Instruments

Design and test results of the calibration unit for the MOAO demonstrator RAVEN - Lavigne, J.-F.; Lamontagne, F.; Anctil, G.; Wang, M.; Tremblay, M.; Lardiere, O.; Nash, R.; Andersen, D.; Savard, M.; Côté, P.; Bradley, C.H.; Châteauneuf, F. (Adaptive Optics Systems III, 2012)
INO has designed, assembled and tested the Raven Multi-Object Adaptive Optics demonstrator calibration unit. This sub-system consists in a telescope simulator that will allow aligning Raven's components during its integration, testing its Adaptive Optics performances in the laboratory and at the telescope, and calibrating the Adaptive Optics system by building the interaction matrix and measuring the non-common path aberrations. The system is presented with the challenges that needed to be overcome during the design and integration phases. The system test results are also presented and compared to the model predictions.
Keywords: Adaptive optics systems; Calibration unit; Illumination system; Interaction matrices; Model prediction; Multiobject; Subaru telescopes; System test; Calibration; Optical design; Optical telescopes

Understanding charge dynamics in silicon dangling bond structures for nanoscale devices - Livadaru, L.; Pitters, J. L.; Taucer, M.; Wolkow, R. A. (Nanotechnology 2012: Technical Proceedings of the 2012 NSTI Nanotechnology Conference and Expo. Volume 1: Advanced materials, CNTs, particles, films and composites, 2012)
A dangling bond (DB) on a silicon surface atomic has been found to behave as an atomic-scale quantum dot. This opens up the possibility of using DBs as building blocks for novel electronic structures, pushing the ultimate limits of nanoscale devices. Examples include: artificial molecules, nanowires, and alternate computing architectures such as the Quantum-Dot Cellular Automata (QCA). We study theoretically various aspects of DB structures on an H-terminated 2x1 Si(001) surface, which are of primary interest for the advancement of any device architecture: (i) The "diatomic" artificial DB molecule, composed of two tunnel-coupled DBs; its coherence and polarization properties in different ionic states; its potential as a charge qubit. (ii) The interaction of such DB structures with external control electrodes and manipulators, including the interaction with a scanning tunneling microscopy (STM) probe.
Keywords: Artificial molecule; Atomic scale; Building blockes; Charge dynamics; Charge qubits; Computing architecture; Device architectures; Electron dynamics; External control; Ionic state; Nanoscale device; Polarization properties; Quantum-dot cellular automata; Si(001) surfaces; Silicon dangling bonds; Silicon surfaces; Dynamics; Electronic structure; Fluidics; Molecules; Nanowires; Scanning tunneling microscopy; Sequential machines; Nanotechnology

Comprehensive microscopy analysis of Au/Ag nanoclusters on silica nanospheres - Qian, H.; Shen, W.-Z.; Cui, K.; Cho, J.-Y.; Fenniri, H. (Nanotechnology 2012: Technical Proceedings of the 2012 NSTI Nanotechnology Conference and Expo. Volume 1: Advanced materials, CNTs, particles, films and composites, 2012)
Gold/silver (Au/Ag) bimetallic nanoclusters (shell) on silica (Au/Ag @ SiO 2) were synthesized by layer-by-layer technique. By adjusting the mole ratio of Au and Ag, the bimetallic alloy on the SiO 2 nanoshpere surface posseses tunable surface plasmon resonance. Several transmission electron microscopy (TEM) techniques have been applied to characterize the structure and morphology of the bimetallic nanoclusters, including scanning transmission electron microscopy (STEM) tomography, high angle angular dark field (HAADF) imaging, energy dispersive X-ray (EDX) spectoscopy, high resolution TEM (HRTEM) and electron diffraction (ED). The results revealed the Au/Ag alloy nanoclusters were interconnected on the surface of SiO 2 nanospheres with the nanoscale roughess varied with the mole ratio of Au and Ag.
Keywords: Bimetallic nanoclusters; ED; HAADF; HRTEM; STEM; Energy dispersive spectroscopy; Films; Nanotechnology; Silica; Silver alloys; Transmission electron microscopy; Nanocomposite films

Synthesis, characterization and viscoelastic properties of nanocrystalline cellulose grafted with poly(N-isopropylacrylamide) - Hemraz, U. D; Danumah, C.; Lu, A.; Boluk, Y. (Nanotechnology 2012: Technical Proceedings of the 2012 NSTI Nanotechnology Conference and Expo. Volume 1: Advanced materials, CNTs, particles, films and composites, 2012)
Nanocrystalline cellulose (NCC) was grafted with the thermo-responsive polymer poly(N-isopropylacrylamide) (Nipaam) via living radical polymerization. Various techniques were used to characterize the physical, chemical, morphological and thermal properties of the resulting material. The viscoelastic properties and the stability of the functionalized NCC were compared to the unmodified NCC using rheometry. The shear viscosity of the NCC suspension decreased slightly with an increase in temperature from 20°C to 45°C, indicating a stable system. The storage modulus and shear viscosity values both exhibited a burst increase at about 32.5°C, which is assigned to be the lower critical solution temperature (LCST) of poly(Nipaam). This indicates the successful functionalization of Nipaam polymer chains on NCC. In addition, the thermodynamic property of poly(Nipaam) also prevailed on the grafted NCC.
Keywords: Functionalizations; Functionalized; Living radical polymerization; Lower critical solution temperature; N-isopropylacrylamides; Nanocrystalline cellulose; Polymer chains; Polymer grafting; Resulting materials; Rheometry; Stable systems; Thermoresponsive polymer; Viscoelastic properties; Viscosity value; Acrylic monomers; Cellulose derivatives; Grafting (chemical); Living polymerization; Polymers; Rheology; Shear viscosity; Thermodynamic properties; Viscoelasticity; Nanocomposite films; Copolymerization; Low Temperature; Polyacrylics; Thin Films

Nanocomposites of nanocrystalline cellulose for biosensor applications - Incani, V.; Danumah, C.; Boluk, Y. (Nanotechnology 2012: Technical Proceedings of the 2012 NSTI Nanotechnology Conference and Expo. Volume 3: Bio Sensors, Instruments, Medical, Environment and Energy, 2012)
In this work, we describe the use of a composite material made of a renewable source and metallic nanoparticles for biosensing applications. NCC is a product isolated from natural cellulose fibers, which is of approx. 100 nm long and 10 nm wide in size. We augmented the surface area and chemical affinity of NCC by optimally dressing it with gold nanoparticles (AuNP). The deposition of AuNP on NCC was controlled by using cationic Polyethylenimine (PEI). AuNPs were thio-funtionalized prior to enzyme immobilization and the enzyme (glucose oxidase) was conjugated on the composite by carbodiimide (EDC)/NHS coupling. Using UV-visible and fluorescence spectroscopy in the presence of a specific substrate we monitored the activity of the immobilized enzymes, and its efficiency was compared with that of the enzyme in free form. Our results using FT-IR and SEM show that thiol-AuNPs were attached to the surface of NCC. The enzymes activity were measured and quantified using different kit assays and proved that the enzymes were attached to the support and maintained their activity.
Keywords: Biosensing applications; Biosensor applications; Carbodiimides; Cationic polyethylenimine; Chemical affinities; Enzymes activity; Freeforms; Gold nanoparticles; Immobilized enzyme; Its efficiencies; Metallic nanoparticles; Nanocrystalline cellulose; Natural cellulose fibers; Renewable sources; Surface area; UV-visible; Biosensors; Cellulose derivatives; Exhibitions; Fluorescence spectroscopy; Glucose oxidase; Glucose sensors; Medical nanotechnology; Metal nanoparticles; Nanocomposites; Nanotechnology; Sensors; Enzyme immobilization; Cellulose Derivatives; Enzymes; Glucose; Gold Compounds; Sensors

Multiscale modeling of the structure and thermodynamics of chemically modified NCC for rational design of NCC-based nanocomposites, gels, and foams - Stoyanov, Stanislav R.; Lyubimova, O.; Cuervo, J. E.; Gusarov, S.; Kobryn, A. E.; Blinov, N.; Kovalenko, A. (TAPPI International Conference on Nanotechnology for Renewable Materials 2012, 2012)

Cationic liposome-mediated CXCR4 gene delivery into hematopoietic stem/progenitor cells: implications for clinical transplantation and gene therapy - Gul-Uludag, Hilal; Xu, Peng; Marquez-Curtis, Leah A.; Xing, James; Janowska-Wieczorek, Anna; Chen, Jie (Stem Cells and Development, 2012)
The chemokine stromal cell-derived factor (SDF)-1α/CXCL12 and its receptor CXC chemokine receptor 4 (CXCR4) play a crucial role in the homing/engraftment and retention of hematopoietic stem/progenitor cells (HSPCs) in the bone marrow. It has been shown using the viral gene transfer technique that CXCR4 overexpression on human CD34+ HSPC significantly improves their engraftment in murine models. However, clinical trials with gene therapy have revealed safety concerns related to the immunogenicity of the viral carriers, due to the random integration of viral genes into the host genome. Therefore, a method for CXCR4 gene delivery into HSPC that is safe, nonviral, and highly efficient is needed to improve clinical transplantation and gene therapies. In this work, we investigated the nonviral CXCR4 gene delivery into HSPC using the cationic liposome agent IBAfect. We used CD34+ cells from cord blood and the models of immature hematopoietic cells expressing CD34 antigen, namely, leukemic cell lines KG-1a and KG-1. Transfection efficiency was determined by flow cytometric analysis 12, 24, 48, and 72 h after transfection, and the viability of cells analyzed by trypan blue exclusion and MTS assays. The functional response of CXCR4-transfected HSPC toward an SDF-1α gradient was determined by chemotaxis assay. We found that ∼25% transfection is achieved for KG-1a and KG-1 cells and 20% for HSPC, and that the viability of CXCR4-transfected HSPC is not significantly altered. More importantly, overexpression of CXCR4 using IBAfect significantly increased the chemotaxis of KG-1 cells and HSPC toward SDF-1α. However, we tested 2 other commercially available cationic liposomes (Lipofectamine 2000 and 1,2-dioleoyl-3- trimethylammonium-propane [DOTAP]) in parallel, and we found that they failed to deliver the CXCR4 gene into cells under the same conditions. These results suggest that IBAfect-mediated in vitro gene delivery to overexpress CXCR4 on HSPC is a safe and efficient technique with great potential for improving the efficacy of HSPC transplantation and gene therapy protocols.
Keywords: CD34 antigen; chemokine receptor CXCR4; liposome; stromal cell derived factor 1alpha; cell migration; cell viability; chemotaxis; cytotoxicity; flow cytometry; gene overexpression; genetic transfection; hematopoietic stem cell; in vitro gene transfer; priority journal; Antigens, CD34; Cell Survival; Cells, Cultured; Chemokine CXCL12; Hematopoietic Stem Cell Transplantation; Hematopoietic Stem Cells; Humans; Liposomes; Receptors, CXCR4; Recombinant Proteins; Transfection; Murinae

Wavefront sensing and correction with the Gemini Planet Imager - Thomas, S.; Poyneer, L.; Savransky, D.; Macintosh, B.; Hartung, M.; Dillon, D.; Gavel, D.; Dunn, Jennifer; Wallace, K.; Palmer, D.; De Rosa, Robert (Adaptive Optics Systems III, 2012)
High-contrast imaging is a growing observational technique aimed at discovering and characterizing extrasolar planets. The Gemini Planet Imager (GPI) is designed to achieve contrast ratios of 10-6 - 10 -7 and requires unprecedented wavefront correction and coronagraphic control of diffraction. GPI is a facility instrument now undergoing integration and testing and is scheduled for first light on the 8-m Gemini South telescope towards the end of 2012. In this paper, we focus on the wavefront sensing and correction aspects of the instrument. To measure the wavefront, GPI combines a Shack-Hartmann wavefront sensor and a high-accuracy infrared interferometric wavefront calibration system. The Shack-Hartmann wavefront sensor uses 1700 subapertures to precisely sample the wavefront at 1.5 kHz and features a spatial filter to prevent aliasing. The wavefront calibration system measures the slower temporal frequency errors as well as non-common path aberrations. The wavefront correction is performed using a two-stage adaptive optics system employing a 9x9 piezoelectric deformable mirror and a 43x43 actuators MEMS deformable mirror operating in a woofer-tweeter configuration. Finally, an image sharpening technique is used to further increase the contrast of the final image. In this paper, we describe the three wavefront sensing methods and how we combine their respective information to achieve the best possible contrast.
Keywords: Adaptive optics systems; Aliasing; Calibration system; Contrast ratio; Deformable mirrors; Extra solar planets; Extrasolar planet detection; Extreme adaptive optics; High contrast imaging; High-accuracy; Image sharpening; MEMS deformable mirror; Shack-Hartmann wavefront sensors; Spatial filters; Sub-apertures; Temporal frequency; Wave-front sensing; Wavefront correction; Adaptive optics; Calibration; Instrument testing; Interferometry; Piezoelectric actuators; Wavefronts

Assembly, integration, and verification (AIV) in ALMA: reries processing of array elements - Lopez, Bernhard; Jager, Rieks; Whyborn, Nicholas D.; Knee, Lewis B. G.; McMullin, Joseph P. (Modeling, Systems Engineering, and Project Management for Astronomy V, 2012)
The Atacama Large Millimeter/submillimeter Array (ALMA) is a joint project between astronomical organizations in Europe, North America, and East Asia, in collaboration with the Republic of Chile. ALMA will consist of at least 54 twelve-meter antennas and 12 seven-meter antennas operating as an aperture synthesis array in the (sub)millimeter wavelength range. It is the responsibility of ALMA AIV to deliver the fully assembled, integrated, and verified antennas (array elements) to the telescope array. After an initial phase of infrastructure setup AIV activities began when the first ALMA antenna and subsystems became available in mid 2008. During the second semester of 2009 a project-wide effort was made to put in operation a first 3-antenna interferometer at the Array Operations Site (AOS). In 2010 the AIV focus was the transition from event-driven activities towards routine series production. Also, due to the ramp-up of operations activities, AIV underwent an organizational change from an autonomous department into a project within a strong matrix management structure. When the subsystem deliveries stabilized in early 2011, steady-state series processing could be achieved in an efficient and reliable manner. The challenge today is to maintain this production pace until completion towards the end of 2013. This paper describes the way ALMA AIV evolved successfully from the initial phase to the present steady-state of array element series processing. It elaborates on the different project phases and their relationships, presents processing statistics, illustrates the lessons learned and relevant best practices, and concludes with an outlook of the path towards completion.
Keywords: Aperture synthesis; Atacama large millimeter/submillimeter array; East Asia; Joint projects; Matrix management; Millimeter wavelength; Project phasis; Series production; Telescope arrays; Assembly; Astronomy; Integration; Verification; Antennas

Optical calibration and testing of the E-ELT M4 adaptive mirror - Spanò, P.; Bianco, A.; Briguglio, R.; Cecconi, M.; Miglietta, L.; Molinari, E.; Pariani, G.; Riccardi, A.; Riva, M.; Tresoldi, D.; Xompero, M.; Zerbi, F. (Adaptive Optics Systems III, 2012)
Innovative optical interferometry test setups and control software techniques have been proposed for the E-ELT M4 adaptive optics mirror. The system is composed of three sub-systems: a CGH-based optical test tower, delivering a 1.5-m collimated beam, for fast simultaneous acquisition of large areas; a stitching interferometer, to calibrate at higher spatial frequencies, on smaller areas; and an optical piston sensor to remove differential piston and tilt between adjacent mirror segments.
Keywords: Interferometry, CGH, stitching, piston sensor, ELTs

FLAMINGOS-2: the facility near-infrared wide-field imager and multi-object spectrograph for Gemini - Eikenberry, Stephen; Bandyopadhyay, Reba; Bennett, J. Greg; Bessoff, Aaron; Branch, Matt; Charcos, Miguel; Corley, Richard; Dewitt, Curtis; Eriksen, John-David; Elston, Richard; Frommeyer, Skip; Gonzalez, Anthony; et al. (Ground-based and Airborne Instrumentation for Astronomy IV, 2012)
We report on the design, on-sky performance, and status of the FLAMINGOS-2 instrument - the fully-cryogenic facility near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048x2048-pixel HAWAII-2 0.9-2.4 μm detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object laser-machined plates or 3 long slits for spectroscopy over a 6x2-arcminute field of view, and selectable grisms provide resolutions from ∼1300 to ∼3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi-Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3x1-arcminute field with high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On-Instrument WaveFront Sensor subsystems. We also present the on-sky performance measured during acceptance testing in 2009, as well as current status of the project and future plans.
Keywords: Band pass; Detector arrays; Field of views; High spatial resolution; Multi-conjugate adaptive optics systems; Multi-object spectrograph; Near Infrared; Wave front sensors; Wheel mechanism; Wide-field imager; Infrared devices; Optical systems; Spectrographs; Pixels

The Next Generation of the Canada-France-Hawaii Telescope: science requirements and survey strategies - McConnachie, Alan; Côté, Patrick; Crampton, David; Devost, Daniel; Simons, Doug; Szeto, Kei (Ground-based and Airborne Telescopes IV, 2012)
A concept study is underway to upgrade the existing 3.6 meter Canada-France-Hawaii Telescope (CFHT) to a 10 meter class, wide-field, dedicated, spectroscopic facility, which will be the sole astronomical resource capable of obtaining deep, spectroscopic follow-up data to the wealth of photometric and astrometric surveys planned for the next decade, and which is designed to tackle driving science questions on the formation of the Milky Way galaxy and the characterization and nature of dark energy. This unique facility will operate at low (R ∼ 2000), intermediate (R ∼ 6000) and high (R ∼ 20000) resolutions over the wavelength range 370 ≤ λ ≤ 1300nm, and will obtain up to 3200 simultaneous spectra per pointing over a 1.5 square degree field. Unlike all other proposed or planned wide field spectroscopic facilities, this "Next Generation CFHT" will combine the power of a 10m aperture with exquisite observing conditions and a mandate for dedicated spectroscopic studies to enable transformative science programs in fields as diverse as exoplanetary host characterization, the interstellar medium, stars and stellar astrophysics, the Milky Way galaxy, the Local Group, nearby galaxies and clusters, galaxy evolution, the inter-galactic medium, dark energy and cosmology. A new collaboration must be formed to make this necessary facility into a reality, and currently nearly 60 scientists from 11 different communities - Australia, Brazil, Canada, China, France, Hawaii, India, Japan, South Korea, Taiwan, USA - are involved in defining the science requirements and survey strategies. Here, we discuss the origins of this project, its motivations, the key science and its flow-down requirements. An accompanying article describes the technical studies completed to date. The final concept study will be submitted to the CFHT Board and Science Advisory Committee in Fall 2012, with first light for the facility aiming to be in the early 2020s.
Keywords: Dark energy; Galaxy evolution; Interstellar mediums; Milky way galaxy; Stellar astrophysics; Wavelength ranges; Wide field; Airborne telescopes; Optical telescopes; Spectroscopic analysis; Spectroscopy; Surveys; Galaxies

Performance of the integral field spectrograph for the Gemini Planet Imager - Chilcote, Jeffrey K.; Larkin, James E.; Maire, Jérôme; Perrin, Marshall D.; Fitzgerald, Michael P.; Doyon, René; Thibault, Simon; Bauman, Brian; Macintosh, Bruce A.; Graham, James R.; Saddlemyer, Les (Ground-based and Airborne Instrumentation for Astronomy IV, 2012)
We present performance results, from in-lab testing, of the Integral Field Spectrograph (IFS) for the Gemini Planet Imager (GPI). GPI is a facility class instrument for the Gemini Observatory with the primary goal of directly detecting young Jovian planets. The GPI IFS is based on concepts from the OSIRIS instrument at Keck and utilizes an infrared transmissive lenslet array to sample a rectangular 2.8 x 2.8 arcsecond field of view. The IFS provides low-resolution spectra across five bands between 1 and 2.5 μm. Alternatively, the dispersing element can be replaced with a Wollaston prism to provide broadband polarimetry across the same five filter bands. The IFS construction was based at the University of California, Los Angeles in collaboration with the Université de Montréal, Immervision and Lawrence Livermore National Laboratory. During its construction, we encountered an unusual noise source from microphonic pickup by the Hawaii-2RG detector. We describe this noise and how we eliminated it through vibration isolation. The IFS has passed its preship review and was shipped to University of California, Santa Cruz at the end of 2011 for integration with the remaining sub-systems of GPI. The IFS has been integrated with the rest of GPI and is delivering high quality spectral datacubes of GPI's coronagraphic field.
Keywords: Extra solar planets; Field of views; HAWAII-2RG; High quality; Integral field spectrograph; Jovian planets; Lawrence livermore national laboratories; Lenslet array; Noise source; Vibration isolations; Wollaston prism; Polarimeters

Interpretation of atomic motion in flexible molecules: accelerating molecular dynamics simulations - Omelyan, Igor; Kovalenko, Andriy (Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 2012)
We propose a new approach to split up the velocities of atoms of flexible molecules into translational, rotational, and vibrational components. As a result, the kinetic energy of the system can easily be expressed in terms of only three parts related to the above components. This is distinct from the standard Eckart method, where the cumbersome Coriolis contribution to the kinetic energy appears additionally. The absence of such a contribution within the proposed approach allows us to readily extend the microcanonical multiple-time-step dynamics of flexible molecules to the canonical-isokinetic Nosé-Hoover chain ensemble by explicitly integrating the translational, orientational, and vibrational motion. The previous extensions dealt exclusively with translational degrees of freedom of separate atoms, leading to a limitation on the size of the outer time step of 100 femtoseconds. We show on molecular dynamics simulations of the flexible TIP3P water model that the new canonical-isokinetic formulation gives a possibility to significantly overcome this limitation. In particular, huge outer time steps of order from a few hundred femtoseconds up to several picoseconds can now be employed to study conformational properties without loss of accuracy.
Keywords: Conformational properties; Coriolis; Femtoseconds; Molecular dynamics simulations; Multiple time step; Picoseconds; Time step; Translational degrees of freedoms; Vibrational components; Vibrational motions; Water models; Degrees of freedom (mechanics); Kinetic energy; Molecular dynamics; Molecules; Atoms

Nanoelectromechanical devices in a fluidic environment - Svitelskiy, Oleksiy; Sauer, Vince; Vick, Douglass; Cheng, Kar-Mun; Liu, Ning; Freeman, Mark R.; Hiebert, Wayne K. (Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 2012)
We present a comprehensive study of nanoelectromechanical systems in pressurized fluids. Resonant responses and quality factors are monitored in five different gases and one liquid, in pressures ranging from vacuum to 20 MPa, in order to evaluate theoretical models of device-fluid interactions at the nanoscale. The traditional Newell picture of microresonator damping in different pressure regimes is found to be inadequate in describing nanoresonators in general. Damping at intermediate pressure ranges is better physically characterized by a Weissenberg number (which compares oscillation frequencies with fluid relaxation rates) than a Knudsen number (which compares mean free paths with device widths) and most adequately described by the Yakhot and Colosqui model. At high-pressure ranges, two models are found to give good agreement with data: the phenomenological model of vibrating spheres and the Sader and Bhiladvala model for the viscous regime. The latter is also successful in explicitly predicting pressure-dependent behavior of the viscous mass load and damping. We observe significant increases in damping due to the squeezed film (SF) of gas between the device and substrate as well as due to undercut (an unavoidable artifact of the standard fabrication technique); correcting the shape of the devices with a focused ion beam allows us to differentiate these two factors. Application of the SF model accounts well for additional damping at high pressures while only qualitatively agreeing at lower pressures. The extensive data collected allow additional insight into fundamental processes underlying fluid damping at the nanoscale, particularly in the intermediate- and high-pressure regimes.
Keywords: Fabrication technique; Fluid damping; High pressure; Intermediate pressures; Knudsen numbers; Lower pressures; Mass load; Mean free path; Micro resonators; Nano scale; Nanoresonators; Oscillation frequency; Phenomenological models; Pressure regime; Quality factors; Relaxation rates; Resonant response; Theoretical models; Weissenberg number; Nanotechnology; Damping

Exploring the cell uptake mechanism of phospholipid and polyethylene glycol coated gold nanoparticles - Hao, Yuzhi; Yang, Xiaoyang; Song, Steven; Huang, Min; He, Chuan; Cui, Mingyang; Chen, Jie (Nanotechnology, 2012)
Recently, there has been a lot of interest in using gold nanoparticles (GNPs) for biomedical applications due to their biocompatibility. To increase GNP cell uptake and circulation half-life, and to improve its bio-distribution invivo, we chose to coat GNPs with 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1- rac-glycerol) (sodium salt) (POPG) and polyethylene glycol (PEG). Two different methods were used to synthesize POPG-GNPs or PEG-GNPs, but the resulting nanoparticle sizes and morphologies were similar. Under the same incubation conditions, POPG-GNPs can be uptaken quicker than PEG-GNPs by cellsspecifically, the maximum uptake was 8h versus 16h after incubation. In addition, the uptake amount of POPG-GNPs was more than that of PEG-GNPs. The uptake processes were confirmed by SEM and TEM images. The main reason for the greater uptake of POPG-GNPs can be attributed to the structural similarities between the POPG coating and the cell membrane as well as GNP aggregation.
Keywords: Biodistributions; Biomedical applications; Cell uptake; In-vivo; Nanoparticle sizes; SEM and TEM; Sodium salt; Structural similarity; Biocompatibility; Cell membranes; Thermoplastics; Polyethylene glycols; 1 palmitoyl 2 oleoylglycero 3 phosphoglycerol; 1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; macrogol derivative; metal nanoparticles; phosphatidylglycerol; cell death; drug effect; endocytosis; tumor cell line; ultrastructure; Phosphatidylglycerols; Polyethylene Glycols

Indium tin oxide nanowhisker morphology control by vapour-liquid-solid glancing angle deposition - Beaudry, A. L.; Tucker, R. T.; Laforge, J. M.; Taschuk, M. T.; Brett, M. J. (Nanotechnology, 2012)
A new growth technique for indium tin oxide nanowhiskers with increased control over feature size and spacing is reported. The technique is based on a unique combination of self-catalysed vapour-liquid-solid (VLS) growth and glancing angle deposition (GLAD). This VLSGLAD technique provides enhanced control over nanowhisker morphology as the effect of typical VLS growth parameters (e.g.flux rate, temperature) is amplified at large deposition angles characteristic of GLAD. Spatial modulation of the collimated growth flux controls trunk width, number and orientation of branches, and overall nanowhisker density. Here we report the influence of growth conditions (including deposition angle, flux rate, nominal pitch and substrate temperature) on nanowhisker morphology, with specific focus on the effect of large deposition angles. Sheet resistance and transmission of the films were measured to characterize their performance as transparent conductive oxides. Hybrid nanostructured films grown in this study include high surface area nanowhiskers protruding from a conductive film, ideal for transparent conductive electrode applications.
Keywords: Deposition angle; Feature sizes; Flux rates; Glancing angle deposition; Growth conditions; Growth flux; Growth techniques; High surface area; Indium tin oxide; Morphology control; Nanostructured Films; Spatial modulations; Substrate temperature; Transparent conductive; Transparent conductive oxides; VLS growth; Crystal whiskers; Indium compounds; Liquids; Morphology; Nanowhiskers; Tin; Tin oxides; Conductive films

Reactive fillers based on SWCNTs functionalized with matrix-based moieties for the production of epoxy composites with superior and tunable properties - González-Domínguez, Jose M.; Martínez-Rubí, Yadienka; Díez-Pascual, Ana M.; Ansón-Casaos, A.; Gómez-Fatou, Marian; Simard, Benoit; Martínez, M. Teresa (Nanotechnology, 2012)
Composite materials based on epoxy matrix and single-walled carbon nanotubes (SWCNTs) are able to exhibit outstanding improvements in physical properties when using a tailored covalent functionalization with matrix-based moieties containing terminal amines or epoxide rings. The proper choice of grafted moiety and integration protocol makes it feasible to tune the composite physical properties. At 0.5wt% SWCNT loading, these composites exhibit up to 65% improvement in storage modulus, 91% improvement in tensile strength, and 65% improvement in toughness. A 15°C increase in the glass transition temperature relative to the parent matrix was also achieved. This suggests that a highly improved interfacial bonding between matrix and filler, coupled to improved dispersion, are achieved. The degradation temperatures show an upshift in the range of 4060°C, which indicates superior thermal performance. Electrical conductivity ranges from 10 13 to 10 3Scm 1, which also shows the possibility of tuning the insulating or conductive behaviour of the composites. The chemical affinity of the functionalization moieties with the matrix and the unchanged molecular structure at the SWCNT/matrix interface are responsible for such improvements.
Keywords: Chemical affinities; Covalent functionalizations; Degradation temperatures; Electrical conductivity; Epoxy composite; Epoxy matrices; Functionalizations; Functionalized; Grafted moieties; Interfacial bonding; Reactive fillers; Thermal Performance; Tunable properties; Electric conductivity; Loading; Physical properties; Single-walled carbon nanotubes (SWCN); Fillers

Pharmacokinetic and toxicological evaluation of multi-functional thiol-6-fluoro-6-deoxy-d-glucose gold nanoparticles in vivo - Roa, Wilson; Xiong, Yeping; Chen, Jie; Yang, Xiaoyan; Song, Kun; Yang, Xiaohong; Kong, Beihua; Wilson, John; Xing, James Z. (Nanotechnology, 2012)
We synthesized a novel, multi-functional, radiosensitizing agent by covalently linking 6-fluoro-6-deoxy-d-glucose (6-FDG) to gold nanoparticles (6-FDG-GNPs) via a thiol functional group. We then assessed the bio-distribution and pharmacokinetic properties of 6-FDG-GNPs in vivo using a murine model. At 2h, following intravenous injection of 6-FDG-GNPs into the murine model, approximately 30% of the 6-FDG-GNPs were distributed to three major organs: the liver, the spleen and the kidney. PEGylation of the 6-FDG-GNPs was found to significantly improve the bio-distribution of 6-FDG-GNPs by avoiding unintentional uptake into these organs, while simultaneously doubling the cellular uptake of GNPs in implanted breast MCF-7 adenocarcinoma. When combined with radiation, PEG-6-FDG-GNPs were found to increase the apoptosis of the MCF-7 breast adenocarinoma cells by radiation both in vitro and in vivo. Pharmacokinetic data indicate that GNPs reach their maximal concentrations at a time window of two to four hours post-injection, during which optimal radiation efficiency can be achieved. PEG-6-FDG-GNPs are thus novel nanoparticles that preferentially accumulate in targeted cancer cells where they act as potent radiosensitizing agents. Future research will aim to substitute the 18F atom into the 6-FDG molecule so that the PEG-6-FDG-GNPs can also function as radiotracers for use in positron emission tomography scanning to aid cancer diagnosis and image guided radiation therapy planning.

Spatial matter density mapping of the STAGES Abell A901/2 supercluster field with 3D lensing - Simon, P.; Heymans, C.; Schrabback, T.; Taylor, A. N.; Gray, M. E.; van Waerbeke, L.; Wolf, C.; Bacon, D.; Barden, M.; Böhm, A.; Häußler, B.; Jahnke, K.; et al. (Monthly Notices of the Royal Astronomical Society, 2012)
We present weak lensing data from the Hubble Space Telescope(HST)/Space Telescope A901/902 Galaxy Evolution Survey (STAGES) survey to study the three-dimensional spatial distribution of matter and galaxies in the Abell 901/902 supercluster complex. Our method improves over the existing 3D lensing mapping techniques by calibrating and removing redshift bias and accounting for the effects of the radial elongation of 3D structures. We also include the first detailed noise analysis of a 3D lensing map, showing that even with deep HST-quality data, only the most massive structures, for example M 200≳ 10 15M ⊙h -1 at z∼ 0.8, can be resolved in 3D with any reasonable redshift accuracy (Δz≈ 0.15). We compare the lensing map to the stellar mass distribution and find luminous counterparts for all mass peaks detected with a peak significance >3σ. We see structures in and behind the z= 0.165 foreground supercluster, finding structure directly behind the A901b cluster at z∼ 0.6 and also behind the south-west (SW) group at z∼ 0.7. This 3D structure viewed in projection has no significant impact on recent mass estimates of A901b or the SW group components SWa and SWb.

The star formation history and dust content in the far outer disc of M31 - Bernard, Edouard J.; Ferguson, Annette M. N.; Barker, Michael K.; Hidalgo, Sebastien L.; Ibata, Rodrigo A.; Irwin, Michael J.; Lewis, Geraint F.; McConnachie, Alan W.; Monelli, Matteo; Chapman, Scott C. (Monthly Notices of the Royal Astronomical Society, 2012)
We present a detailed analysis of two fields located 26kpc (∼5 radial scalelengths) from the centre of M31 along the south-west semimajor axis of the disc. One field samples the major axis populations - the Outer Disc field - while the other is offset by ∼18arcmin and samples the warp in the stellar disc - the warp field. The colour-magnitude diagrams (CMDs) based on Hubble Space Telescope Advanced Camera for Surveys imaging reach old main-sequence turn-offs (∼12.5Gyr). We apply the CMD-fitting technique to the warp field to reconstruct the star formation history (SFH). We find that after undergoing roughly constant star formation until about 4.5Gyr ago, there was a rapid decline in activity and then a ∼1.5Gyr lull, followed by a strong burst lasting 1.5Gyr and responsible for 25 per cent of the total stellar mass in this field. This burst appears to be accompanied by a decline in global metallicity which could be a signature of the inflow of metal-poor gas. The onset of the burst (∼3Gyr ago) corresponds to the last close passage of M31 and M33 as predicted by detailed N-body modelling, and may have been triggered by this event. We reprocess the deep M33 outer disc field data of Barker et al. in order to compare consistently derived SFHs. This reveals a similar duration burst that is exactly coeval with that seen in the M31 warp field, lending further support to the interaction hypothesis. We reliably trace star formation as far back as 12-13Gyr ago in the outer disc of M31, while the onset of star formation occurred about 2Gyr later in M33, with median stellar ages of 7.5 and 4.5Gyr, respectively. The complex SFHs derived, as well as the smoothly varying age-metallicity relations, suggest that the stellar populations observed in the far outer discs of both galaxies have largely formed in situ rather than migrated from smaller galactocentric radii. The strong differential reddening affecting the CMD of the Outer Disc field prevents derivation of the SFH using the same method. Instead, we quantify this reddening and find that the fine-scale distribution of dust precisely follows that of the Hi gas. This indicates that the outer Hi disc of M31 contains a substantial amount of dust and therefore suggests significant metal enrichment in these parts, consistent with inferences from our CMD analysis.

Variable stars in the Cetus dwarf spheroidal galaxy: population gradients and connections with the star formation history - Monelli, M.; Bernard, E. J.; Gallart, C.; Fiorentino, G.; Drozdovsky, I.; Aparicio, A.; Bono, G.; Cassisi, S.; Skillman, E. D.; Stetson, P. B. (Monthly Notices of the Royal Astronomical Society, 2012)
We investigate the variable star content of the isolated, Local Group, dwarf spheroidal (dSph) galaxy Cetus. Multi-epoch, wide-field images collected with the Very Large Telescope/Visible Multiobject Spectrograph camera allowed us to detect 638 variable stars (630 RRLyrae stars and eight anomalous Cepheids), 475 of which are new detections. We present a full catalogue of periods, amplitudes and mean magnitudes. Motivated by the recent discovery that the pulsational properties of the RRLyrae stars in the Tucana dSph revealed the presence of a metallicity gradient within the oldest (>rsim10Gyr old) stellar populations, we investigated the possibility of an analogous effect in Cetus. We found that, despite the obvious radial gradient in the horizontal branch and red giant branch morphologies, both becoming bluer on average for increasing distance from the centre of Cetus, the properties of the RRLyrae stars are homogeneous within the investigated area (out to r∼ 15arcmin), with no significant evidence of a radial gradient. We discuss this in connection with the star formation history previously derived for the two galaxies. The observed differences between these two systems show that even systems this small show a variety of early evolutionary histories. These differences could be due to different merger or accretion histories.

The structure of star clusters in the outer halo of M31 - Tanvir, N. R.; Mackey, A. D.; Ferguson, A. M. N.; Huxor, A.; Read, J. I.; Lewis, G. F.; Irwin, M. J.; Chapman, S.; Ibata, R.; Wilkinson, M. I.; McConnachie, A. W.; Martin, N. F.; et al. (Monthly Notices of the Royal Astronomical Society, 2012)
We present a structural analysis of halo star clusters in M31 based on deep Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) imaging. The clusters in our sample span a range in galactocentric projected distance from 13 to 100kpc and thus reside in rather remote environments. Ten of the clusters are classical globulars, whilst four are from the Huxor et al. population of extended, old clusters. For most clusters, contamination by M31 halo stars is slight, and so the profiles can be mapped reliably to large radial distances from their centres. We find that the extended clusters are well fit by analytic King profiles with ∼20 parsec core radii and ∼100 parsec photometric tidal radii, or by Sérsic profiles of index ∼1 (i.e. approximately exponential). Most of the classical globulars also have large photometric tidal radii in the range 50-100 parsec; however, the King profile is a less good fit in some cases, particularly at small radii. We find 60 percent of the classical globular clusters exhibit cuspy cores which are reasonably well described by Sérsic profiles of index ∼2-6. Our analysis also reinforces the finding that luminous classical globulars, with half-light radii <10 parsec, are present out to radii of at least 100kpc in M31, which is in contrast to the situation in the Milky Way where such clusters (other than the unusual object NGC 2419) are absent beyond 40kpc.

GALAPAGOS: from pixels to parameters - Barden, Marco; Häußler, Boris; Peng, Chien Y.; McIntosh, Daniel H.; Guo, Yicheng (Monthly Notices of the Royal Astronomical Society, 2012)
To automate source detection, two-dimensional light profile Sérsic modelling and catalogue compilation in large survey applications, we introduce a new code Galaxy Analysis over Large Areas: Parameter Assessment by galfitting Objects from SExtractor (galapagos). Based on a single set-up, galapagos can process a complete set of survey images. It detects sources in the data, estimates a local sky background, cuts postage stamp images for all sources, prepares object masks, performs Sérsic fitting including neighbours and compiles all objects in a final output catalogue. For the initial source detection, galapagos applies SExtractor, while galfit is incorporated for modelling Sérsic profiles. It measures the background sky involved in the Sérsic fitting by means of a flux growth curve. galapagos determines postage stamp sizes based on SExtractor shape parameters. In order to obtain precise model parameters, galapagos incorporates a complex sorting mechanism and makes use of modern CPU's multiplexing capabilities. It combines SExtractor and galfit data in a single output table. When incorporating information from overlapping tiles, galapagos automatically removes multiple entries from identical sources. galapagos is programmed in the Interactive Data Language (idl). We test the stability and the ability to properly recover structural parameters extensively with artificial image simulations. Moreover, we apply galapagos successfully to the STAGES data set. For one-orbit Hubble Space Telescope data, a single 2.2-GHz CPU processes about 1000 primary sources per 24h. Note that galapagos results depend critically on the user-defined parameter set-up. This paper provides useful guidelines to help the user make sensible choices.

Magnetic field, differential rotation and activity of the hot-Jupiter-hosting star HD 179949 - Fares, R.; Donati, J.-F.; Moutou, C.; Jardine, M.; Cameron, A. C.; Lanza, A. F.; Bohlender, D.; Dieters, S.; Martínez Fiorenzano, A. F.; Maggio, A.; Pagano, I.; Shkolnik, E. L. (Monthly Notices of the Royal Astronomical Society, 2012)
HD 179949 is an F8V star, orbited by a giant planet at ∼8 Rblack star every 3.092514 d. The system was reported to undergo episodes of stellar activity enhancement modulated by the orbital period, interpreted as caused by star-planet interactions (SPIs). One possible cause of SPIs is the large-scale magnetic field of the host star in which the close-in giant planet orbits. In this paper we present spectropolarimetric observations of HD 179949 during two observing campaigns (2009 September and 2007 June). We detect a weak large-scale magnetic field of a few gauss at the surface of the star. The field configuration is mainly poloidal at both observing epochs. The star is found to rotate differentially, with a surface rotation shear of dΩ= 0.216 ± 0.061 rad d-¹, corresponding to equatorial and polar rotation periods of 7.62 ± 0.07 and 10.3 ± 0.8d, respectively. The coronal field estimated by extrapolating the surface maps resembles a dipole tilted at ∼70°. We also find that the chromospheric activity of HD 179949 is mainly modulated by the rotation of the star, with two clear maxima per rotation period as expected from a highly tilted magnetosphere. In 2009 September, we find that the activity of HD 179949 shows hints of low-amplitude fluctuations with a period close to the beat period of the system.

The Volume-limited A-Star (VAST) survey - II. Orbital motion monitoring of A-type star multiples - De Rosa, R. J.; Patience, J.; Vigan, A.; Wilson, P. A.; Schneider, A.; Mcconnell, N.J.; Wiktorowicz, S. J.; Marois, C.; Song, I.; Macintosh, B.; Graham, J. R.; Bessell, M. S.; et al. (Monthly Notices of the Royal Astronomical Society, 2012)
As a part of our ongoing Volume-limited A-Star (VAST) adaptive optics survey, we have obtained observations of 26 binary systems with projected separations <100 au, 13 of which have sufficient historical measurements to allow for refinement of their orbital elements. For each system with an estimated orbit, the dynamical system mass obtained was compared with the system mass estimated from mass-magnitude relations. Discrepancies between the dynamical and theoretical system mass can be explained by the presence of a previously unresolved spectroscopic component or by a non-solar metallicity of the system. Using this approach to infer the presence of additional companions, a lower limit to the fraction of binaries, triples and quadruples can be estimated as 39, 46 and 15per cent for systems with at least one companion within 100 au. The fraction of multiple systems with three or more components shows a relative increase compared to the fraction for solar-type primaries resolved in previous volume-limited surveys. The observations have also revealed a pair of potentially young (<100Myr) M dwarf companions, which would make an ideal benchmark for the theoretical models during the pre-main-sequence contraction phase for M dwarfs. In addition to those systems with orbit fits, we report 13 systems for which further orbital monitoring observations are required, 11 of which are newly resolved as a part of the VAST survey.

Herschel imaging of 61Vir: implications for the prevalence of debris in low-mass planetary systems - Wyatt, M. C.; Kennedy, G.; Sibthorpe, B.; Moro-Martín, A.; Lestrade, J.-F.; Ivison, R.J.; Matthews, B.; Udry, S.; Greaves, J. S.; Kalas, P.; Lawler, S.; Su, K. Y. L.; et al. (Monthly Notices of the Royal Astronomical Society, 2012)
This paper describes Herschel observations of the nearby (8.5pc) G5V multi-exoplanet host star 61Vir at 70, 100, 160, 250, 350 and 500m carried out as part of the DEBRIS survey. These observations reveal emission that is significantly extended out to a distance of >15arcsec with a morphology that can be fitted by a nearly edge-on (77° inclination) radially broad (from 30au out to at least 100au) debris disc of fractional luminosity 2.7 × 10^-5, with two additional (presumably unrelated) sources nearby that become more prominent at longer wavelengths. Chance alignment with a background object seen at 1.4GHz provides potential for confusion, however, the star's 1.4 arcsec yr-¹ proper motion allows archival Spitzer 70m images to confirm that what we are interpreting as disc emission really is circumstellar. Although the exact shape of the disc's inner edge is not well constrained, the region inside 30au must be significantly depleted in planetesimals. This is readily explained if there are additional planets outside those already known (i.e. in the 0.5-30au region), but is also consistent with collisional erosion. We also find tentative evidence that the presence of detectable debris around nearby stars correlates with the presence of the lowest mass planets that are detectable in current radial velocity surveys. Out of an unbiased sample of the nearest 60G stars, 11 are known to have planets, of which six (including 61Vir) have planets that are all less massive than Saturn, and four of these have evidence for debris. The debris towards one of these planet hosts (HD20794) is reported here for the first time. This fraction (4/6) is higher than that expected for nearby field stars (15per cent), and implies that systems that form low-mass planets are also able to retain bright debris discs. We suggest that this correlation could arise because such planetary systems are dynamically stable and include regions that are populated with planetesimals in the formation process where the planetesimals can remain unperturbed over Gyr time-scales.

Theoretical investigation of planar square carbon allotrope and its hydrogenation - Pujari, Bhalchandra S.; Tokarev, Andrey; Saraf, Deepashri A. (Journal of Physics: Condensed Matter, 2012)
Using density functional theory we investigate a novel carbon allotrope SqC: a square planar material that can be more than tetracoordinated. Carbon atoms in this 2D square Bravais lattice form an unusual five-center four-electron bond with neighboring four carbon atoms (tetracoordination). Such an electron-deficient bonding leaves an empty orbital which enables penta- or hexa-coordinated carbon atom. Indeed, our simulations demonstrate such penta- and hexa-coordinated configurations upon partial and complete hydrogenation, respectively. Surprisingly, in all the forms SqC shows the metallic character. SqC has the binding energy of 6.7eV and it also satisfies the Born stability criteria. Yet our phonon calculations show that it may only be considered as quasi-stable.

Testing the limits: America's Cup performance evaluations - Pallard, Robert (Journal of Ocean Technology, 2012)
The National Research Council-Institute for Ocean Technology (NRC-IOT) is Canada's national centre for ocean technology research and development. It was established in 1985 to support the development of innovative technologies in the private sector and to assist oceans-related public initiatives. The Institute's capability is unique to the nation - no other organization offers the combination of knowledge, experience and world-class facilities. Research is conducted on technologies for use in ocean observation, marine safety, Arctic operations and performance evaluation. Major facilities operated by the Institute include a 200-metre Towing Tank, a 75-metre by 32-metre Offshore Engineering Basin, and a 90-metre Ice Tank, the longest in the world. In this essay, author Robert Pallard talks about America's Cup testing that took place at the Institute over a 16-year period.

Infrared spectroscopy of nearby radio active elliptical galaxies - Mould, Jeremy; Reynolds, Tristan; Readhead, Tony; Floyd, David; Jannuzi, Buell; Cotter, Garret; Ferrarese, Laura; Matthews, Keith; Atlee, David; Brown, Michael (The Astrophysical Journal: Supplement Series, 2012)
In preparation for a study of their circumnuclear gas we have surveyed 60% of a complete sample of elliptical galaxies within 75 Mpc that are radio sources. Some 20% of our nuclear spectra have infrared emission lines, mostly Paschen lines, Brackett γ, and [Fe II]. We consider the influence of radio power and black hole mass in relation to the spectra. Access to the spectra is provided here as a community resource.

Discovery of the host cluster for the fundamental Cepheid calibrator zeta Geminorum - Majaess, D.; Turner, D.; Gieren, W.; Balam, D.; Lane, D. (The Astrophysical Journal Letters, 2012)
New and existing CORAVEL, UBVJHKs, HST, HIP/Tycho, ARO, KPNO, and DAO observations imply that the fundamental Cepheid calibrator ζ Gem is a cluster member. The following parameters were inferred for ζGem from cluster membership and are tied to new spectral classifications (DAO) established for 26 nearby stars (e.g., HD53588/B7.5IV, HD54692/B9.5IV): E B-V = 0.02 ± 0.02, log τ = 7.85 ± 0.15, and d = 355 ± 15 pc. The mean distance to ζ Gem from cluster membership and six recent estimates (e.g., IRSB) is d=363 ± 9(σx)±26(σ) pc. The results presented here support the color-excess and HST parallax derived for the Cepheid by Benedict et al. Forthcoming precise proper motions (DASCH) and Chandra/XMM-Newton observations of the broader field may be employed to identify cluster members, bolster the cluster's existence, and provide stronger constraints on the Cepheid's fundamental parameters. © 2012. The American Astronomical Society. All rights reserved.

Molecular tracers of turbulent shocks in giant molecular clouds - Pon, A.; Johnstone, D.; Kaufman, M. J. (The Astrophysical Journal, 2012)
Giant molecular clouds contain supersonic turbulence and simulations of magnetohydrodynamic turbulence show that these supersonic motions decay in roughly a crossing time, which is less than the estimated lifetimes of molecular clouds. Such a situation requires a significant release of energy. We run models of C-type shocks propagating into gas with densities around 10 3cm -3 at velocities of a fewkms -1, appropriate for the ambient conditions inside of a molecular cloud, to determine which species and transitions dominate the cooling and radiative energy release associated with shock cooling of turbulent molecular clouds. We find that these shocks dissipate their energy primarily through CO rotational transitions and by compressing pre-existing magnetic fields. We present model spectra for these shocks, and by combining these models with estimates for the rate of turbulent energy dissipation, we show that shock emission should dominate over emission from unshocked gas for mid to high rotational transitions (J > 5) of CO. We also find that the turbulent energy dissipation rate is roughly equivalent to the cosmic-ray heating rate and that the ambipolar diffusion heating rate may be significant, especially in shocked gas.

The resolved structure and dynamics of an isolated dwarf galaxy: a VLT and Keck spectroscopic survey of WLM - Leaman, Ryan; Venn, Kim A.; Brooks, Alyson M.; Battaglia, Giuseppina; Cole, Andrew A.; Ibata, Rodrigo A.; Irwin, Mike J.; McConnachie, Alan W.; Mendel, J. Trevor; Tolstoy, Eline (The Astrophysical Journal, 2012)
We present spectroscopic data for 180 red giant branch (RGB) stars in the isolated dwarf irregular galaxy Wolf-Lundmark-Mellote (WLM). Observations of the calcium II triplet lines in spectra of RGB stars covering the entire galaxy were obtained with FORS2 at the Very Large Telescope and DEIMOS on Keck II, allowing us to derive velocities, metallicities, and ages for the stars. With accompanying photometric and radio data we have measured the structural parameters of the stellar and gaseous populations over the full galaxy. The stellar populations show an intrinsically thick configuration with 0.39 ≤ q 0 ≤ 0.57. The stellar rotation in WLM is measured to be 17 ± 1 km s-¹; however, the ratio of rotation to pressure support for the stars is V/σ 1, in contrast to the gas, whose ratio is seven times larger. This, along with the structural data and alignment of the kinematic and photometric axes, suggests we are viewing WLM as a highly inclined oblate spheroid. Stellar rotation curves, corrected for asymmetric drift, are used to compute a dynamical mass of (4.3 ± 0.3) × 10^8 M ☉ at the half-light radius (r h = 1656 ± 49pc). The stellar velocity dispersion increases with stellar age in a manner consistent with giant molecular cloud and substructure interactions producing the heating in WLM. Coupled with WLM's isolation, this suggests that the extended vertical structure of its stellar and gaseous components and increase in stellar velocity dispersion with age are due to internal feedback, rather than tidally driven evolution. These represent some of the first observational results from an isolated Local Group dwarf galaxy that can offer important constraints on how strongly internal feedback and secular processes modulate star formation and dynamical evolution in low-mass isolated objects. © 2012 The American Astronomical Society. All rights reserved.

Anchoring the distance scale VIA X-ray/infrared data for Cepheid clusters: SU Cas - Majaess, D.; Turner, D. G.; Gallo, L.; Gieren, W.; Bonatto, C.; Lane, D.J.; Balam, D.; Berdnikov, L. (The Astrophysical Journal, 2012)
New X-ray (XMM-Newton) and JHK s (Observatoire du Mont-Mégantic) observations for members of the star cluster Alessi 95, which Turner etal. discovered hosts the classical Cepheid SU Cas, were used in tandem with UCAC3 (proper motion) and Two Micron All Sky Survey observations to determine precise cluster parameters: E(J - H) = 0.08 ± 0.02 and d = 405 ± 15 pc. The ensuing consensus among cluster, pulsation, and trigonometric distances (d=414±5((σx)±10((σ) pc) places SU Cas in a select group of nearby fundamental Cepheid calibrators (δ Cep, ζ Gem). High-resolution X-ray observations may be employed to expand that sample as the data proved pertinent for identifying numerous stars associated with SU Cas. Acquiring X-ray observations of additional fields may foster efforts to refine Cepheid calibrations used to constrain H 0.

Aspect ratio dependence of the free-fall time for non-spherical symmetries - Pon, Andy; Toalá, Jesús A.; Johnstone, Doug; Vázquez-Semadeni, Enrique; Heitsch, Fabian; Gómez, Gilberto C. (The Astrophysical Journal, 2012)
We investigate the collapse of non-spherical substructures, such as sheets and filaments, which are ubiquitous in molecular clouds. Such non-spherical substructures collapse homologously in their interiors but are influenced by an edge effect that causes their edges to be preferentially accelerated. We analytically compute the homologous collapse timescales of the interiors of uniform-density, self-gravitating filaments and find that the homologous collapse timescale scales linearly with the aspect ratio. The characteristic timescale for an edge-driven collapse mode in a filament, however, is shown to have a square-root dependence on the aspect ratio. For both filaments and circular sheets, we find that selective edge acceleration becomes more important with increasing aspect ratio. In general, we find that lower dimensional objects and objects with larger aspect ratios have longer collapse timescales. We show that estimates for star formation rates, based upon gas densities, can be overestimated by an order of magnitude if the geometry of a cloud is not taken into account.
Keywords: ISM: clouds; ISM: structure; stars: formation

A Bayesian approach to locating the red giant branch tip magnitude. II. Distances to the satellites of M31 - Conn, A. R.; Ibata, R. A.; Lewis, G. F.; Parker, Q. A.; Zucker, D. B.; Martin, N. F.; McConnachie, A. W.; Irwin, M. J.; Tanvir, N.; Fardal, M. A.; Ferguson, A. M. N.; Chapman, S. C.; et al. (The Astrophysical Journal, 2012)
In "A Bayesian Approach to Locating the Red Giant Branch Tip Magnitude (Part I)," a new technique was introduced for obtaining distances using the tip of the red giant branch (TRGB) standard candle. Here we describe a useful complement to the technique with the potential to further reduce the uncertainty in our distance measurements by incorporating a matched-filter weighting scheme into the model likelihood calculations. In this scheme, stars are weighted according to their probability of being true object members. We then re-test our modified algorithm using random-realization artificial data to verify the validity of the generated posterior probability distributions (PPDs) and proceed to apply the algorithm to the satellite system of M31, culminating in a three-dimensional view of the system. Further to the distributions thus obtained, we apply a satellite-specific prior on the satellite distances to weight the resulting distance posterior distributions, based on the halo density profile. Thus in a single publication, using a single method, a comprehensive coverage of the distances to the companion galaxies of M31 is presented, encompassing the dwarf spheroidals Andromedas I-III, V, IX-XXVII, and XXX along with NGC147, NGC185, M33, and M31 itself. Of these, the distances to Andromedas XXIV-XXVII and Andromeda XXX have never before been derived using the TRGB. Object distances are determined from high-resolution tip magnitude posterior distributions generated using the Markov Chain Monte Carlo technique and associated sampling of these distributions to take into account uncertainties in foreground extinction and the absolute magnitude of the TRGB as well as photometric errors. The distance PPDs obtained for each object both with and without the aforementioned prior are made available to the reader in tabular form. The large object coverage takes advantage of the unprecedented size and photometric depth of the Pan-Andromeda Archaeological Survey. Finally, a preliminary investigation into the satellite density distribution within the halo is made using the obtained distance distributions. For simplicity, this investigation assumes a single power law for the density as a function of radius, with the slope of this power law examined for several subsets of the entire satellite sample.

Filamentary star formation: observing the evolution toward flattened envelopes - Lee, Katherine; Looney, Leslie; Johnstone, Doug; Tobin, John (The Astrophysical Journal, 2012)
Filamentary structures are ubiquitous from large-scale molecular clouds (a few parsecs) to small-scale circumstellar envelopes around Class 0 sources (∼1000 AU to ∼0.1 pc). In particular, recent observations with the Herschel Space Observatory emphasize the importance of large-scale filaments (a few parsecs) and star formation. The small-scale flattened envelopes around Class 0 sources are reminiscent of the large-scale filaments. We propose an observationally derived scenario for filamentary star formation that describes the evolution of filaments as part of the process for formation of cores and circumstellar envelopes. If such a scenario is correct, small-scale filamentary structures (0.1 pc in length) with higher densities embedded in starless cores should exist, although to date almost all the interferometers have failed to observe such structures. We perform synthetic observations of filaments at the prestellar stage by modeling the known Class 0 flattened envelope in L1157 using both the Combined Array for Research in Millimeter-wave Astronomy (CARMA) and the Atacama Large Millimeter/Submillimeter Array (ALMA). We show that with reasonable estimates for the column density through the flattened envelope, the CARMA D array at 3 mm wavelengths is not able to detect such filamentary structure, so previous studies would not have detected them. However, the substructures may be detected with the CARMA D+E array at 3 mm and the CARMA E array at 1 mm as a result of more appropriate resolution and sensitivity. ALMA is also capable of detecting the substructures and showing the structures in detail compared to the CARMA results with its unprecedented sensitivity. Such detection will confirm the new proposed paradigm of non-spherical star formation.

The Canada-France-Hawaii telescope legacy survey: stacked images and catalogs - Gwyn, Stephen D. J. (The Astronomical Journal, 2012)
This paper describes the image stacks and catalogs of the Canada-France-Hawaii Telescope Legacy Survey produced using the MegaPipe data pipeline at the Canadian Astronomy Data Centre. The Legacy Survey is divided into two parts. The Deep Survey consists of four fields each of 1 deg^2, with magnitude limits (50% completeness for point sources) of u = 27.5, g = 27.9, r = 27.7, i = 27.4, and z = 26.2. It contains 1.6 × 10^6 sources. The Wide Survey consists of 150 deg^2 split over four fields, with magnitude limits of u = 26.0, g = 26.5, r = 25.9, i = 25.7, and z = 24.6. It contains 3 × 10^7 sources. This paper describes the calibration, image stacking, and catalog generation process. The images and catalogs are available on the web through several interfaces: normal image and text file catalog downloads, a "Google Sky" interface, an image cutout service, and a catalog database query service. © 2012. National Research Council Canada. All rights reserved.

The observed properties of dwarf galaxies in and around the Local Group - McConnachie, Alan W. (The Astronomical Journal, 2012)
Positional, structural, and dynamical parameters for all dwarf galaxies in and around the Local Group are presented, and various aspects of our observational understanding of this volume-limited sample are discussed. Over 100 nearby galaxies that have distance estimates reliably placing them within 3Mpc of the Sun are identified. This distance threshold samples dwarfs in a large range of environments, from the satellite systems of the MW and M31, to the quasi-isolated dwarfs in the outer regions of the Local Group, to the numerous isolated galaxies that are found in its surroundings. It extends to, but does not include, the galaxies associated with the next nearest groups, such as Maffei, Sculptor, and IC 342. Our basic knowledge of this important galactic subset and their resolved stellar populations will continue to improve dramatically over the coming years with existing and future observational capabilities, and they will continue to provide the most detailed information available on numerous aspects of dwarf galaxy formation and evolution. Basic observational parameters, such as distances, velocities, magnitudes, mean metallicities, as well as structural and dynamical characteristics, are collated, homogenized (as far as possible), and presented in tables that will be continually updated to provide a convenient and current online resource. As well as discussing the provenance of the tabulated values and possible uncertainties affecting their usage, the membership and spatial extent of the MW sub-group, M31 sub-group, and the Local Group are explored. The morphological diversity of the entire sample and notable sub-groups is discussed, and timescales are derived for the Local Group members in the context of their orbital/interaction histories. The scaling relations and mean stellar metallicity trends defined by the dwarfs are presented, and the origin of a possible "floor" in central surface brightness (and, more speculatively, stellar mean metallicity) at faint magnitudes is considered. © 2012. National Research Council Canada. All rights reserved.

Alternative proton exchange membranes by chain-growth polymerization - Tsang, E. M. W.; Holdcroft, S. (Polymer Science: A Comprehensive Reference, 2012)
Polymer microstructure and morphology are critical to the design of proton exchange membranes for fuel cells, as are synthetic methodologies for accessing well-defined polymers with controlled architectures and molecular weights. In this chapter, the synthesis of vinyl-based polymers bearing strong acid groups is considered, together with ion aggregation, phase separation, water sorption, and proton conductivity. Proton-conducting polymers are distinguished according to their microstructure into subheadings of random, block, and graft copolymers. The formation, dimensions, and connectivity of ionic pathways are consistently found to play a profound role in determining both water sorption and proton conductivity. This chapter addresses the significant research that has been carried out to obtain a more comprehensive understanding of relationships between polymer architecture, morphology, and electrolytic properties.

Characterization of genes encoding for acquired bacitracin resistance in Clostridium perfringens - Charlebois, Audrey; Jalbert, Louis-Alexandre; Harel, Josée; Masson, Luke; Archambault, Marie (PLoS ONE, 2012)
Phenotypic bacitracin resistance has been reported in Clostridium perfringens. However, the genes responsible for the resistance have not yet been characterized. Ninety-nine C. perfringens isolates recovered from broilers and turkeys were tested for phenotypic bacitracin resistance. Bacitracin MIC90 (>256 μg/ml) was identical for both turkey and chicken isolates; whereas MIC50 was higher in turkey isolates (6 μg/ml) than in chicken isolates (3 μg/ml). Twenty-four of the 99 isolates showed high-level bacitracin resistance (MIC breakpoint >256 μg/ml) and the genes encoding for this resistance were characterized in C. perfringens c1261_A strain using primer walking. Sequence analysis and percentages of amino acid identity revealed putative genes encoding for both an ABC transporter and an overproduced undecaprenol kinase in C. perfringens c1261_A strain. These two mechanisms were shown to be both encoded by the putative bcrABD operon under the control of a regulatory gene, bcrR. Efflux pump inhibitor thioridazine was shown to increase significantly the susceptibility of strain c1261_A to bacitracin. Upstream and downstream from the bcr cluster was an IS1216-like element, which may play a role in the dissemination of this resistance determinant. Pulsed-field gel electrophoresis with prior double digestion with I-CeuI/MluI enzymes followed by hybridization analyses revealed that the bacitracin resistance genes bcrABDR were located on the chromosome. Semi-quantitative RT-PCR demonstrated that this gene cluster is expressed under bacitracin stress. Microarray analysis revealed the presence of these genes in all bacitracin resistant strains. This study reports the discovery of genes encoding for a putative ABC transporter and an overproduced undecaprenol kinase associated with high-level bacitracin resistance in C. perfringens isolates from turkeys and broiler chickens.
Keywords: ABC transporter; bacitracin; phosphotransferase; thioridazine; undecaprenol kinase; amino acid sequence; antibiotic resistance; bacterial strain; bacterium isolate; bcrABDR gene; bcrR gene; broiler; Clostridium perfringens; gene cluster; gene identification; gene location; gene overexpression; gene sequence; microarray analysis; minimum inhibitory concentration; morphological trait; nucleotide sequence; operon; pulsed field gel electrophoresis; quantitative study; regulator gene; reverse transcription polymerase chain reaction; Clostridium perfringens; Drug Resistance, Microbial; Electrophoresis, Gel, Pulsed-Field; Genes, Bacterial; Microbial Sensitivity Tests; Molecular Sequence Data; Nucleic Acid Hybridization; Oligonucleotide Array Sequence Analysis; Plasmids; Clostridium perfringens; Gallus gallus

Dry etching of copper phthalocyanine thin films: Effects on morphology and surface stoichiometry - Van Dijken, Jaron G.; Brett, Michael J. (Molecules, 2012)
We investigate the evolution of copper phthalocyanine thin films as they are etched with argon plasma. Significant morphological changes occur as a result of the ion bombardment; a planar surface quickly becomes an array of nanopillars which are less than 20 nm in diameter. The changes in morphology are independent of plasma power, which controls the etch rate only. Analysis by X-ray photoelectron spectroscopy shows that surface concentrations of copper and oxygen increase with etch time, while carbon and nitrogen are depleted. Despite these changes in surface stoichiometry, we observe no effect on the work function. The absorbance and X-ray diffraction spectra show no changes other than the peaks diminishing with etch time. These findings have important implications for organic photovoltaic devices which seek nanopillar thin films of metal phthalocyanine materials as an optimal structure.
Keywords: carbon; copper; indole derivative; nitrogen; organometallic compound; oxygen; phthalocyanine copper; article; chemistry; gas laser; surface property; X ray photoelectron spectroscopy; Carbon; Copper; Indoles; Lasers, Gas; Nitrogen; Organometallic Compounds; Oxygen; Photoelectron Spectroscopy; Surface Properties

Specific energy as a characterizing parameter for laser welded Ti-5Al-5V-5Mo-3Cr alloy - Shariff, Tasneem; Cao, Xinjin; Chromik, Richard; Gholipour Baradari, Javad; Wanjara, Priti; Cuddy, Jonathan; Birur, Anand (THERMEC 2011 : International conference on processing and manufacturing of advanced materials : processing, fabrication, properties, applications, 2012)
In this study, specific energy was calculated and correlated with the geometries, defects, microstructures, hardness values and tensile properties of the laser welded Ti-5553 alloy. It was found that specific energy is a good parameter to characterize the laser welding process.
Keywords: Hardness values; ND : YAG lasers; Specific energy; Ti-5553; Welding process; Alloys; Cerium alloys; Chromium alloys; Molybdenum; Neodymium lasers; Titanium; Vanadium; Welding; Titanium alloys; Neodymium lasers

Nanostructured YSZ thin film for application as electrolyte in an electrode supported SOFC - Halmenschlager, Cibele Melo; KorbRoberto, Maita De Angelis; Neagu, Roberto; Bergmann, Carlos Pérez; Malfatti, Célia de Fraga (Advanced powder technology VIII : selected, peer reviewed papers from the eighth Latin American Conference on Powder Technology, November 6-9, 2011, Florianópolis, Brazil, 2012)
The development of solid oxide fuel cell with thin film concepts for an electrode supported design based on the yttria-stabilized zirconia has demonstrated favourable results due to its high chemistry stability in oxidization and environment reduction. The spray pyrolysis process was investigated in order to obtain dense thin films of YSZ on different substrates. The precursor solution was obtained by zirconium and yttrium salt dissolutions in a mixture of water and glycerine in several ratios to study the solvent influence. The substrate was initially heated at 600 °C and during the deposition it ranged from 260-350°C, finishing at a fast increase in temperature of 600°C. The heat treatment was carried out in four different temperatures: 700 °C, 750 °C, 800 °C, and 900 °. The precursors were characterized by thermal analysis. The microstructures of the films were studied using scanning electron microscopy and X-ray diffraction. The results obtained showed that the films obtained were crystalline before the heat treatment process and have shown ionic conductivity above 800°C.
Keywords: Dense thin films; Different substrates; Heat treatment process; Nano-structured; Oxidization; Precursor solutions; Pyrolysis process; Salt dissolution; Solvent influence; YSZ thin films; Glycerol; Scanning electron microscopy; Solid oxide fuel cells (SOFC); Spray pyrolysis; Thermoanalysis; X ray diffraction; Yttria stabilized zirconia; Yttrium; Zirconia; Zirconium; Vapor deposition

Study of the interaction of polymethylmethacrylate fragments with methyl isobutyl ketone and isopropyl alcohol - Mohammad, Mohammad Ali; Poulose Santo, Kolattukudy; Dew, Steven K.; Stepanova, Maria (Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, 2012)
Exposure of polymethylmethacrylate (PMMA) during electron beam lithography (EBL) produces small polymer fragments that dissolve rapidly during the development process. The resist dissolution behavior varies greatly depending on the nature of the developer (solvent) and therefore influences the selection of the EBL parameters, such as dose (sensitivity). A molecular scale examination of the development process is necessary to elucidate the resist-developer interaction mechanisms. In this work, the authors investigate the interaction of short PMMA chains (containing up to 10 MMA units) with common developer components methyl isobutyl ketone (MIBK) and isopropyl alcohol (IPA). For this purpose, the authors conduct molecular dynamics simulations using the Accelrys Materials Studio package. The simulation results were used to characterize the mixtures in the spirit of the Flory-Huggins theory of polymers and also to extract the diffusivities. The authors found that the behavior of PMMA fragments differed considerably in MIBK as compared with IPA. PMMA fragments containing more than three monomers exhibit stronger attractive interaction with MIBK. For all fragment sizes simulated, the diffusivity of PMMA fragments is 60-160 higher in MIBK as well. Similarly, the authors observed differences in the gyration radii. The authors conclude that the kinetic factor seems to be more significant as compared to affinity factor when accounting for differences in exposure sensitivities due to developer selection.
Keywords: Development process; Dissolution behavior; Exposure sensitivity; Flory-Huggins theory; Fragment sizes; Gyration radii; Interaction mechanisms; Isopropyl alcohols; Kinetic factors; Materials Studio; Methyl isobutyl ketone; Molecular dynamics simulations; Molecular scale; Polymer fragments; Electron beam lithography; Ketones; Molecular dynamics; Organic compounds; Polyesters; Polymers; Acrylic monomers

Metal oxide morphology in argon-assisted glancing angle deposition - Sorge, J. B.; Taschuk, M. T.; Wakefield, N. G.; Sit, J. C.; Brett, M. J. (Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, 2012)
Glancing angle deposition (GLAD) is a thin film deposition technique capable of fabricating columnar architectures such as posts, helices, and chevrons with control over nanoscale film features. Argon bombardment during deposition modifies the GLAD process, producing films with new morphologies which have shown promise for sensing and photonic devices. The authors report modification of column tilt angle, film density, and specific surface area for 12 different metal oxide and fluoride film materials deposited using Ar-assisted GLAD. For the vapor flux/ion beam geometry and materials studied here, with increasing argon flux, the column tilt increases, film density increases, and specific surface area decreases. With a better understanding of the nature of property modification and the mechanisms responsible, the Ar-assisted deposition process can be more effectively targeted towards specific applications, including birefringent thin films or photonic crystal square spirals. © 2012 American Vacuum Society.
Keywords: Argon flux; Beam geometry; Birefringent thin films; Columnar architectures; Deposition process; Film density; Film materials; Glancing Angle Deposition; Metal oxides; Nanoscale films; Thin-film deposition technique; Tilt angle; Vapor fluxes; Metallic compounds; Photonic crystals; Specific surface area; Morphology

Nanopillar ITO electrodes via argon plasma etching - Van Dijken, Jaron G.; Brett, Michael J. (Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, 2012)
The authors demonstrate the formation of vertically aligned indium tin oxide (ITO) nanopillars by exposing planar ITO films to Ar plasma, the conditions of which determine the size, spacing, and aspect ratio of the pillars. Annealing in air and forming gas is used to recover and optimize the optical transmittance and electrical conductivity of the nanopillar films. The final product is an ITO film whose superior optical transmittance and strong electrical conductivity combine with its robust columnar morphology and processing scalability to make it suitable for use in highly absorbing organic solar cells.
Keywords: Ar plasmas; Argon plasma etching; Columnar morphology; Electrical conductivity; Forming gas; Indium tin oxide; ITO electrodes; ITO films; Nanopillars; Organic solar cell; Vertically aligned; Electric conductivity; Opacity; Tin oxides; Nanostructures

FITC delivery into plant cells using magnetic single-walled carbon nanotubes - Hao, Yuzhi; Yang, Xiaoyan; Shi, Yongzhong; Xing, James; Marowitch, Janet; Chen, Jianmin; Chen, Jie (Journal of Nanoscience and Nanotechnology, 2012)
In this paper, fluoresce in isothiocyanate (FITC) was covalently bonded with magnetic single-walled carbon nanotubes (mSWCNTs) that were purified using our previous method. To demonstrate our design, mSWCNT-FITC was delivered into plant cells (canola and carrot cells) driven by external magnetic forces. From FACS results, the FITC delivery efficiency was about 100% for both two canola and carrot protoplasts, which were further confirmed by the confocal and sectional TEM images. Some mSWCNTs were found trapped both inside the endosomes of canola protoplast and outside endosome near the nuclear membrane of carrot protoplast according to the sectional TEM images. All results showed that mSWCNT is a good delivery carrier for biomolecules.
Keywords: Covalently bonded; Endosomes; FITC Delivery; Fluorescein isothiocyanate; Magnetic force; Magnetic Single-Walled Carbon Nanotubes (SWCNTs); Nuclear membranes; Plant cells; Protoplast of Canola and Carrot; TEM images; Cell membranes; Plant cell culture; Single-walled carbon nanotubes (SWCN)

Magnetic gold nanoparticles: synthesis, characterization and its application in the delivery of FITC into KG-1 cells - Hao, Yuzhi; Song, Steven; Yang, Xiaoyan; Xing, James; Chen, Jie (Journal of Nanoscience and Nanotechnology, 2012)
In this article, we report a new method\-a sonication method to disperse iron oxide nanoparticles into smaller nanoparticles and make gold ions absorb onto the surface or trapped in the micropores of the iron oxide nanoparticles using sonication action. By using quick reduction of ascorbic acid and post-HCl solution treatment, gold covered magnetic nanoparticles (mGNPs) with spherical morphology and uniform size were synthesized in a water solution. The size of the mGNPs was found to be 20-30 nm. Some ideal mGNPs possessed a core-shell structure. The mGNPs were non-cytotoxic and mGNP-fluorescein isothiocyanate (FITC) can enter KG-1 cells when driven by an external magnetic force, which was confirmed by confocal imaging. The confocal image also showed the FITC inside the KG-1 cells was near the nucleus. The fluorescein isothiocyanate (FITC) delivery efficiency is about 100% according to the flow cytometry results.
Keywords: Confocal imaging; Core shell structure; Iron oxide nanoparticle; Isothiocyanates; Magnetic force; Magnetic nanoparticles; Micropores; Solution treatments; Sonication method; Spherical morphologies; Flow cytometry; Metal nanoparticles; Organic acids; Synthesis (chemical); fluorescein isothiocyanate; atomic force microscopy; confocal microscopy; fluorescence microscopy

Silicon nanowire core aluminum shell coaxial nanocomposites for lithium ion battery anodes grown with and without a TiN interlayer - Memarzadeh, Elmira L.; Kalisvaart, W. Peter; Kohandehghan, Alireza; Zahiri, Beniamin; Holt, Chris M. B.; Mitlin, David (Journal of Materials Chemistry, 2012)
We investigated the effect of aluminum coating layers and of the support growth substrates on the electrochemical performance of silicon nanowires (SiNWs) used as negative electrodes in lithium ion battery half-cells. Extensive TEM and SEM analysis was utilized to detail the cycling induced morphology changes in both the Al-SiNW nanocomposites and in the baseline SiNWs. We observed an improved cycling performance in the Si nanowires that were coated with 3 and 8 wt.% aluminum. After 50 cycles, both the bare and the 3 wt.% Al coated nanowires retained 2600 mAh/g capacity. However beyond 50 cycles, the coated nanowires showed higher capacity as well as better capacity retention with respect to the first cycle. Our hypothesis is that the nanoscale yet continuous electrochemically active aluminum shell places the Si nanowires in compression, reducing the magnitude of their cracking/disintegration and the subsequent loss of electrical contact with the electrode. We combined impedance spectroscopy with microscopy analysis to demonstrate how the Al coating affects the solid electrolyte interface (SEI). A similar thickness alumina (Al 2O 3) coating, grown via atomic layer deposition (ALD), was shown not to be as effective in reducing the long-term capacity loss. We demonstrate that an electrically conducting TiN barrier layer present between the nanowires and the underlying stainless steel current collector leads to a higher specific capacity during cycling and a significantly improved coulombic efficiency. Using TiN the irreversible capacity loss was only 6.9% from the initial 3581 mAh/g, while the first discharge (lithiation) capacity loss was only 4%. This is one of the best combinations reported in literature.
Keywords: Al coatings; Barrier layers; Capacity loss; Capacity retention; Coulombic efficiency; Current collector; Cycling performance; Electrical contacts; Electrochemical performance; First cycle; First discharge; Growth substrates; Impedance spectroscopy; Irreversible capacity loss; Lithiation; Lithium-ion battery; Morphology changes; SEM analysis; Silicon nanowires; Solid electrolyte interfaces; Specific capacities; Alumina; Atomic layer deposition; Electrochemical electrodes; Lithium batteries; Lithium compounds; Nanocomposites; Solid electrolytes; Tinning; Titanium nitride

Microelectronic-sensing assay to detect presence of Verotoxins in human faecal samples - Xing, J. Z.; Zhu, L.; Huang, B.; Chen, J.; Gabos, S. (Journal of Applied Microbiology, 2012)
Aims: To develop a novel Vero cell assay that implements a real-time cell electronic sensing (RT-CES) system for the determination of the presence of verotoxin-producing Escherichia coli (VTEC). The assay overcomes the major drawbacks in conventional Vero cell assay, for example, labour-intensive and time-consuming. Methods and Results: Cells were grown onto the surfaces of microelectronic sensors that are integrated into the bottom surfaces of the microtiter plate. Cellular viability was monitored in real-time and quantified based on changes in the sensor's electrical impedance. For cell viability measurement, the data generated on the RT-CES system correlated well with those obtained by the Vero cell assay for Verotoxins. To assess cytotoxicity, test cells growing on microelectronic sensors were treated with either supernatant from pure cultures, or stool samples. The specific neutralizing antibodies of VT1 and VT2 were used to identify specific toxins in the samples. Conclusions: The RT-CES assay provides a sensitive measurement comparable to conventional crystal violet assay. The assay has been successfully and specifically used to identify VTEC in human faecal samples. Significance and Impact of the Study: The RT-CES assay significantly shortens the testing time from 48 to 72h required by the crystal violet assay to only 15h with automated operation.
Keywords: Escherichia coli; real-time cell electronic sensing assay; vero cell assay; verotoxin assay

Study of development processes for ZEP-520 as a high-resolution positive and negative tone electron beam lithography resist - Mohammad, Mohammad Ali; Koshelev, Kirill; Fito, Taras; Zheng, David Ai Zhi; Stepanova, Maria; Dew, Steven (Japanese Journal of Applied Physics, 2012)
ZEP brand electron beam resists are well-known for their high sensitivity and etch durability. The various performance metrics such as sensitivity, contrast, and resolution of ZEP resist depend strongly on the development process. In this work, we investigate the development of ZEP-520 resist through contrast curves, dense gratings, and surface roughness measurements using three different classes of developer systems of varying solvation strength, ZED-N50, methyl isobutyl ketone (MIBK): isopropyl alcohol (IPA) 1:3, and IPA: H 2O 7:3, at the ambient temperature (22 °C) and cold (°15 °C) development conditions. In order to provide a deeper insight into the ZEP development process, we propose a novel kinetic model of dissolution for ZEP, and develop an efficient analytical method that allows determining the microscopic parameters of ZEP dissolution based on experimental contrast curves. We also observe experimentally and characterize the negative tone behavior of ZEP for dense grating patterning and compare its performance with positive tone behavior.
Keywords: Analytical method; Dense gratings; Development process; Electron beam resist; High resolution; High sensitivity; Isopropyl alcohols; Kinetic models; Methyl isobutyl ketone; Microscopic parameter; Negative tones; Performance metrics; Positive tone; Electron beams; Ketones; Dissolution

Linking the chemistry and physics of electronic charge transfer in insulators: theory and experiment - Veregin, Richard P. N.; Hawkins, Michael S.; Li, Qingbin; Gusarov, Sergey; Kovalenko, Andriy (NIP28 : 28th international conference on digital printing technologies : technical program and proceedings : Digital fabrication 2012, 2012)
The surface states model is successful in predicting many salient features of charge transfer in insulative materials, which is critical to electrophotography. This paper will discuss how the surface chemistry controls the physics, the chemical potentials, and how it fits the surface states model. The interrelationship of acid-base Ka/Kb values of the materials in contact, measured by IGC (inverse gas chromatography), the HOMO (highest occupied molecular orbitals) and LUMO (lowest unoccupied molecular orbitals) and their excited states calculated using DFT (density functional theory) quantum mechanical modeling, the chemical potentials measured by the Kelvin method, and triboelectric charging data are studied. It will be shown that a precursor complex of the contacting materials, prior to the charge transfer event, can be calculated by DFT to predict both qualitatively and quantitatively triboelectric charging. The work focuses on PTFE, Kynar and PMMA polymers, as well as silica, titania and alumina.
Keywords: Electronic charges; Electrophotography; Highest occupied molecular orbital; Inverse gas chromatography; Lowest unoccupied molecular orbital; Precursor complexes; Quantum-mechanical modeling; Triboelectric charging; Alumina; Chemical potential; Density functional theory; Gas chromatography; Molecular orbitals; Photography; Quantum theory; Silica; Surface chemistry; Surface states; Charge transfer

Multi-platform characterization of the human cerebrospinal fluid metabolome: a comprehensive and quantitative update - Mandal, Rupasri; Guo, An Chi; Chaudhary, Kruti K.; Liu, Philip; Yallou, Faizath S.; Dong, Edison; Aziat, Farid; Wishart, David S. (Genome Medicine, 2012)
Background: Human cerebral spinal fluid (CSF) is known to be a rich source of small molecule biomarkers for neurological and neurodegenerative diseases. In 2007, we conducted a comprehensive metabolomic study and performed a detailed literature review on metabolites that could be detected (via metabolomics or other techniques) in CSF. A total of 308 detectable metabolites were identified, of which only 23% were shown to be routinely identifiable or quantifiable with the metabolomics technologies available at that time. The continuing advancement in analytical technologies along with the growing interest in CSF metabolomics has led us to re-visit the human CSF metabolome and to re-assess both its size and the level of coverage than can be achieved with today's technologies.Methods: We used five analytical platforms, including nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), direct flow injection-mass spectrometry (DFI-MS/MS) and inductively coupled plasmas-mass spectrometry (ICP-MS) to perform quantitative metabolomics on multiple human CSF samples. This experimental work was complemented with an extensive literature review to acquire additional information on reported CSF compounds, their concentrations and their disease associations.Results: NMR, GC-MS and LC-MS methods allowed the identification and quantification of 70 CSF metabolites (as previously reported). DFI-MS/MS allowed the quantification of 78 metabolites (6 acylcarnitines, 13 amino acids, hexose, 42 phosphatidylcholines, 2 lyso-phosphatidylcholines and 14 sphingolipids), while ICP-MS provided quantitative results for 33 metal ions in CSF. Literature analysis led to the identification of 57 more metabolites. In total, 476 compounds have now been confirmed to exist in human CSF.Conclusions: The use of improved metabolomic and other analytical techniques has led to a 54% increase in the known size of the human CSF metabolome over the past 5 years. Commonly available metabolomic methods, when combined, can now routinely identify and quantify 36% of the 'detectable' human CSF metabolome. Our experimental works measured 78 new metabolites that, as per our knowledge, have not been reported to be present in human CSF. An updated CSF metabolome database containing the complete set of 476 human CSF compounds, their concentrations, related literature references and links to their known disease associations is freely available at the CSF metabolome database.
Keywords: acylcarnitine; amino acid; hexose; lyso phosphatidylcholine derivative; phosphatidylcholine; sphingolipid; unclassified drug; article; cerebrospinal fluid; direct flow injection mass spectrometry; human; liquid chromatography; mass fragmentography; mass spectrometry; metabolite; metabolome; nuclear magnetic resonance; priority journal

Mode suppressing packaging for 50 GHz cryogenic low-noise amplifiers - Henke, Doug; Jiang, Frank; Claude, Stéphane (Microwave Conference (EuMC), 2012 42nd European, 2012)
Hybrid cryogenic low-noise amplifiers are often enclosed in a metallic housing with several bias channels. Strict machining tolerance is necessary for solid clamping of the lid to avoid degradation in performance. A new packaging is proposed by applying photonic bandgap (PBG) structures; which greatly relaxes the tolerance on clamping' results in natural bias channels' suppresses higher order modes' and creates wide open access for assembly.
Keywords: Higher-order modes; Open Access; Photonic band-gap structures; Photonic bandgap (PBG); Cryogenics; Microwave amplifiers; Microwaves; Millimeter wave devices; Packaging; Periodic structures; Spontaneous emission; Low noise amplifiers

Ultrafast carrier dynamics in silicon nanocrystal films - Titova, Lyubov V.; Cocker, Tyler L.; Wang, Xiongyao; Meldrum, Al; Hegmann, Frank A. (Nanoscale Luminescent Materials 2, 2012)
We have applied time-resolved THz spectroscopy to probe the transient photoexcited carrier dynamics and THz conductivity in Si nanocrystal films with varying silicon volume filling fractions and nanocrystal sizes on picosecond time scales. The THz conductivity reveals microscopic carrier motion with significant interface scattering within nanocrystals as well as percolative transport between nanocrystals. The time variation of the THz conductivity is analyzed within the framework of the Drude-Smith model, an extension of the Drude model that characterizes carrier localization in nanostructured materials. Below the percolation threshold, transport between nanocrystals is inhibited and photoexcited carriers are localized within individual nanocrystals. These films also exhibit efficient optical emission. In films with Si filling fractions above the percolation threshold, photoluminescence is suppressed and a transition from long-range inter-nanocrystal transport immediately after photoexcitation to increased carrier localization over a 50 ps time scale due to accumulation of charges at interface defect sites is observed.
Keywords: Carrier localization; Drude models; Filling fractions; Interface defects; Interface scattering; Nanocrystal sizes; Optical emissions; Percolation thresholds; Photoexcited carriers; Picosecond time scale; Si nanocrystal; Silicon nanocrystals; Thz spectroscopy; Time variations; Time-resolved; Time-scales; Ultrafast carrier dynamics; Nanocrystals; Nanotechnology; Optical waveguides; Percolation (computer storage); Percolation (fluids); Photoexcitation; Silicon; Interfaces (materials)

Molecular theory of solvation and electrical double layer in nanoporous carbon electrodes - Kovalenko, Andriy (Electrochemical capacitors, fundamentals to applications, 2012)
Electrical double layer (EDL) in a nanoporous electrode is very different from a planar electrochemical capacitor. The statistical-mechanical, molecular theory of solvation structure and thermodynamics (a.k.a. RISM-KH) is an essential part of multiscale methodology properly accounting for environment effects and chemical specificities of nanosystems in solution. Its generalization to solutions sorbed in disordered nanoporous materials using the replica method for statistical mechanics of quenched-annealed systems, replica RISM-KH-VM theory, provides full microscopic details of the solvation structure and thermodynamics as well as the electrochemical properties averaged over the thermal motion of sorbed solution and over quenched morphology of host nanoporous material. The replica RISM-KH-VM theory reveals the molecular mechanisms and driving forces of sorption of electrolyte solution in a nanoporous carbon electrode which are drastically different from the electrical double layer in electrolyte solution at a planar electrode. These include nanoporous confinement morphology and external charge, size and chemical specificities of solvent and electrolyte, osmotic forces, the internal EDL at the surface of nanopores and the external EDL at the contact with bulk solution. The interplay of these factors determines the efficiency of an electrosorption cell and the specific capacitance of the electrochemical supercapacitor.
Keywords: Electrical double layers; Electrochemical capacitor; Electrochemical supercapacitor; Electrolyte solutions; Molecular theory of solvation; Nano-porous materials; Nanoporous carbon electrode; Quenched-annealed systems; Capacitors; Electric properties; Electrochemical electrodes; Morphology; Nanopores; Plasma interactions; Porous materials; Solvation; Statistical mechanics; Thermodynamics; Electrolytes

Real-time monitoring of adherent Vero cell density and apoptosis in bioreactor processes - Petiot, Emma; El-Wajgali, Amal; Esteban, Geoffrey; Gény, Cécile; Pinton, Hervé; Marc, Annie (Cytotechnology, 2012)
This study proposes an easy to use in situ device, based on multi-frequency permittivity measurements, tomonitor the growth and death ofattached Vero cells cultivated on microporous microcarriers, without any cell sampling. Vero cell densities were on-line quantified up to 10 6 cell mL -1. Some parameters which could potentially impact Vero cell morphological and physiological states were assessed through different culture operating conditions, such as media formulation or medium feed-harvest during cell growth phase. A new methodofinsitu cell death detection with dielectric spectroscopy was also successfully implemented. Thus, through permittivity frequency scanning, major rises of the apoptotic cell population in bioreactor cultures were detected by monitoring the characteristic frequency of the cell population, f c, which is one of the culture dielectric parameters. Both cell density quantification and cell apoptosis detection are strategic information in cell-based production processes as they are involved in major events of the process, suchasscale-uporchoice of the viral infection conditions. This new application of dielectric spectroscopy to adherent cell culture processes makes it a very promising tool for risk-mitigation strategy in industrial processes. Therefore, our results contribute to the development of Process Analytical Technology in cell-based industrial processes.
Keywords: apoptosis; in situ monitoring; cell density; Multi-frequency permittivity; Adherent Vero cell

Efficient and rapid uptake of magnetic carbon nanotubes into human monocytic cells: implications for cell-based cancer gene therapy - Gul-Uludag, Hilal; Lu, Weibing; Xu, Peng; Xing, James; Chen, Jie (Biotechnology Letters, 2012)
Monocyte-based gene therapies in cancer have been hampered by either the resistance of these cells to non-viral molecular delivery methods or their poor trafficking to the tumor site after their ex vivo manipulations. Magnetic nanoparticles (MNP)-loaded genetically engineered monocytes can efficiently delivered to tumor site by external magnetic field, but they are not ideal delivery tools due to their spherical shape. Hence, we have investigated the cellular uptake efficiency and cytotoxicity of fluorescein isothiocyanate (FITC)-labelled magnetic carbon nanotubes (FITC-mCNT) in human monocytic leukemia cell line THP-1 for application in cell-based gene therapy against cancer. Uptake of FITC-mCNT into THP-1 cells reached 100% only 1 h after the delivery. Confocal imaging confirmed that FITC-mCNT entered the cell cytoplasm and even into the nucleus. FITC-mCNT uptake did not compromise cell viability. This delivery system might therefore enhance cell-based cancer gene therapies.
Keywords: Cancer; Cellular and nuclear uptake; Fluorescein isothiocyanate; Gene therapies; Magnetic carbon nanotubes; Monocytic leukemia cells

Evolution in the volumetric type Ia supernova rate from the supernova legacy survey - Perrett, K.; Sullivan, M.; Conley, A.; González-Gaitán, S.; Carlberg, R.; Fouchez, D.; Ripoche, P.; Neill, J. D.; Astier, P.; Balam, D.; Balland, C.; Basa, S.; et al. (Astronomical Journal, 2012)
We present a measurement of the volumetric Type Ia supernova (SN Ia) rate (SNR Ia) as a function of redshift for the first four years of data from the Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). This analysis includes 286 spectroscopically confirmed and more than 400 additional photometrically identified SNe Ia within the redshift range 0.1 ≤ z ≤ 1.1. The volumetric SNR Ia evolution is consistent with a rise to z 1.0 that follows a power law of the form (1+z) α, with α = 2.11 ± 0.28. This evolutionary trend in the SNLS rates is slightly shallower than that of the cosmic star formation history (SFH) over the same redshift range. We combine the SNLS rate measurements with those from other surveys that complement the SNLS redshift range, and fit various simple SN Ia delay-time distribution (DTD) models to the combined data. A simple power-law model for the DTD (i.e., t -β) yields values from β = 0.98 ± 0.05 to β = 1.15 ± 0.08 depending on the parameterization of the cosmic SFH. A two-component model, where SNR Ia is dependent on stellar mass (M stellar) and star formation rate (SFR) as SNR Ia(z) = A × M stellar(z) + B × SFR(z), yields the coefficients A = (1.9 ± 0.1) × 10 -14 SNe yr -1 M -1 ⊙ and B = (3.3 ± 0.2) × 10 -4 SNe yr -1 (M ⊙ yr -1) -1. More general two-component models also fit the data well, but single Gaussian or exponential DTDs provide significantly poorer matches. Finally, we split the SNLS sample into two populations by the light-curve width (stretch), and show that the general behavior in the rates of faster-declining SNe Ia (0.8 ≤ s < 1.0) is similar, within our measurement errors, to that of the slower objects (1.0 ≤ s < 1.3) out to z 0.8. © © 2012. The American Astronomical Society. All rights reserved..

Sky coverage modeling for the whole sky for laser guide star multiconjugate adaptive optics - Wang, Lianqi; Andersen, David; Ellerbroek, Brent (Applied Optics, 2012)
The scientific productivity of laser guide star adaptive optics systems strongly depends on the sky coverage, which describes the probability of finding natural guide stars for the tip/tilt wavefront sensor(s) to achieve a certain performance. Knowledge of the sky coverage is also important for astronomers planning their observations. In this paper, we present an efficient method to compute the sky coverage for the laser guide star multiconjugate adaptive optics system, the Narrow Field Infrared Adaptive Optics System (NFIRAOS), being designed for the Thirty Meter Telescope project.We show that NFIRAOS can achieve more than 70% sky coverage over most of the accessible sky with the requirement of 191 nm total rms wavefront.
Keywords: Laser guide star adaptive optics; Multi-conjugate adaptive optics systems; Natural guide star; Sky coverage; Thirty Meter Telescope; Wave front sensors; Wavefronts

Naturally aspirating isokinetic total water content probe: pre-flight wind tunnel testing and design modifications - Davison, Craig R.; Rutke, Tim; Strapp, J. Walter; Ratvasky, Thomas P.; Emery, Edward F. (4th AIAA Atmospheric and Space Environments Conference, 2012)

Photonic crystal paddle nanocavities for optomechanical torsion sensing - Wu, Marcelo; Hryciw, Aaron C.; Khanaliloo, Behzad; Freeman, Mark R.; Davis, John P.; Barclay, Paul E. (2012 Conference on Lasers and Electro-Optics (CLEO), 2012)
Photonic crystal nanocavities with suspended central elements suitable for optomechanical detection of torsional forces are designed and fabricated. This "floating" low mass nanocavity may be mechanically coupled to nanomagnetic structures.
Keywords: Crystal nanocavities; Low mass; Nano-cavities; Optomechanical; Torsional forces; Lasers; Photonic crystals

Effective g-factor in high-mobility InGaAs/InP quantum well - Wei, Lai-Ming; Zhou, Yuan-Ming; Yu, Guo-Lin; Gao, Kuang-Hong; Liu, Xin-Zhi; Lin, Tie; Guo, Shao-Ling; Dai, Ning; Chu, Jun-Hao; Austing, David Guy (Acta Physica Sinica, 2012)
High-mobility In 0.53Ga 0.47As/InP quantum well is fabricated by the chemical beam epitaxy technique. Clear Shubnikov-de Hass (SdH) oscillation and beating pattern due to zero-field spin splitting are observed by magnetotransport measurements at low temperature. We use an analytical method, involving the simultaneous fitting of fast Fourier transform spectra of SdH oscillations at different tilted fields, to extract the effective g-factor.

A rapid fuzzy optimisation approach to multiple sources water blending problem in water distribution systems - Peng, Wei; Mayorga, Rene V.; Imran, Syed (Urban Water Journal, 2012)
This paper proposes a Fuzzy Response Surface Optimisation (FRSO) approach for the water blending problem of multiple sources to maintain the water quality in water distribution systems. In the proposed approach, instead of the more precise and complicated nonlinear equations, the response surface models are used to describe the harmful reaction kinetics. The objectives of this study are to minimise the harmful reactions in the water network. A fuzzy linear programming using the min-operator approach is applied to handle the multiple objectives. Due to the FRSO only containing quadratic models, this approach is easy to apply and the optimisation is performed rapidly. Hence, the FRSO can be used to dynamically estimate the optimal blending ratios of water coming from multiple sources. Finally, a case study and two comparisons demonstrate the FRSO's advantages as to computational efficiency and simultaneous optimisation.
Keywords: water quality, water blend, multi-objective, fuzzy linear programming, response surface method

The effect of overlap percentage on surface quality in laser polishing of AISI H13 tool steel - Hafiz, Abdullah Khalid; Bordatchev, Evgueni; Tutunea-Fatan, Remus (40th North American Manufacturing Research Conference 2012: Notre Dame, Indiana, USA, 4-8 June 2012., 2012)
Polishing by laser beam radiation is a novel technique used to modify the initial surface geometry in order to achieve a desired level of surface finish. The performance of laser polishing (LP) is determined by its process parameters, whose optimum combination is essential for the achievement of the best possible surface quality. In this regard, the overlap percentage is one of the important LP settings, which indicates the level of the overlap between two consecutive polishing tracks. In the current study, the effects of overlap percentage were experimentally investigated in the context of AISI H13 tool steel LP operations. Four surface areas were polished using four different overlap percentages but the same applied energy density. The improvement of surface quality was measured by average spatial surface roughness and material ratio function. The surface quality improvement was also analyzed by means of statistical analysis using the autospectrum and the transfer functions. Finally, the polished area created by the optimum overlap from the aforementioned analyses was further processed by an additional level of LP improving a total average surface roughness from 1.59 μm to 0.18 μm (89% improvement).
Keywords: AISI H13; Energy density; Laser polishing; Overlap percentage; Surface waviness; Industrial research; Lasers; Manufacture; Polishing; Surface roughness; Tool steel; Transfer functions; Surface properties

The roles of diffusion factors in electrochemical corrosion of TiN and CrN (CrSiCN) coated mild steel and stainless steel - Cai, Feng; Yang, Qi; Huang, Xiao (TMS 2012, 141st Annual Meeting & Exhibition, Supplemental Proceedings. Volume 1, Materials Processing and Interfaces, 2012)
Applying noble coatings on steel components is an effective solution to preventing corrosion attacks. However, through-coating defects, such as pin holes, voids and growth defects play a detrimental role in the degradation of a coating-substrate system. Through the defects, corrosive media are able to reach the metal substrate, initializing pitting corrosion and eventually resulting in coating failure. This research studies the correlation between coating defects and corrosion behavior of the TiN and CrN (CrSiCN) coated mild steel and stainless steel. Electrochemical impedance technique is used to reveal the corrosion behavior. The results revealed that in a coating-substrate system, two critical factors controlling the corrosion resistance, the effective diffusion coefficient and diffusion layer thickness, which are found to be related to coating microstructure. Denser and thicker coating structures result in lower effective diffusion coefficients and greater effective diffusion layer thickness, and demonstrate high electrochemical impedance and resistance to electrochemical corrosion.
Keywords: PVD coating, coating defect, corrosion, electrochemical impedance, EIS

Toxicological effects of functionalized single-walled carbon nanotubes (SWCNTs) on embryonic zebrafish (Danio rerio) - Felix, L.; Martinez-Rubi, Y.; Simard, B.; Goss, G. (Nanotechnology 2012: Technical Proceedings of the 2012 NSTI Nanotechnology Conference and Expo. Volume 3: Bio Sensors, Instruments, Medical, Environment and Energy, 2012)
Since their discovery in 1993, single-walled carbon nanotubes (SWCNTs) have played an integral role in nanotechnology and have been extensively studied due to their unique structural, electrical and mechanical properties. Chemical functionalization and coating of SWCNTs can improve their solubility in water and organic solvents to allow use in solution-based techniques and extend range of applications. We tested 1) aqueous lignin-wrapped 10-20nm and 2) carboxy-functionalized 10-20 nm SWCNTs, manufactured by the National Research Council - Steacie Institute for Molecular Sciences (NRC-SIMS), to determine the effect of different degrees of solubility. To determine the toxicological effect, we exposed zebrafish (Danio rerio) embryos over a 72-hour period to a range (1, 10, 50, 100 and 200mg/L) of functionalized and un-functionalized SWCNTs as a paired control following Organization for Economic Co-Operation and Development (OECD) guidelines. Toxicological endpoints such as lethality, hatch inhibition and changes in gene expression were measured. While preliminary results show no significant difference in survival and hatch compared to control, effects may occur at the molecular level. Our goal was to determine the toxicological effects of different degrees of functionalized SWCNTs at whole animal and molecular levels.
Keywords: Aquatic animals; Aquatic ecosystem; Chemical functionalization; Nanotoxicology; Potential indicators; Pristine materials; Sublethal effects; Toxicological effects; Medical nanotechnology

Applications of amniotic membrane and fluid in stem cell biology and regenerative medicine - Rennie, Kerry; Gruslin, Andrée; Hengstschläger, Markus; Pei, Duanqing; Cai, Jinglei; Nikaido, Toshio; Bani-Yaghoub, Mahmud (Stem Cells International, 2012)
The amniotic membrane (AM) and amniotic fluid (AF) have a long history of use in surgical and prenatal diagnostic applications, respectively. In addition, the discovery of cell populations in AM and AF which are widely accessible, nontumorigenic and capable of differentiating into a variety of cell types has stimulated a flurry of research aimed at characterizing the cells and evaluating their potential utility in regenerative medicine. While a major focus of research has been the use of amniotic membrane and fluid in tissue engineering and cell replacement, AM- and AF-derived cells may also have capabilities in protecting and stimulating the repair of injured tissues via paracrine actions, and acting as vectors for biodelivery of exogenous factors to treat injury and diseases. Much progress has been made since the discovery of AM and AF cells with stem cell characteristics nearly a decade ago, but there remain a number of problematic issues stemming from the inherent heterogeneity of these cells as well as inconsistencies in isolation and culturing methods which must be addressed to advance the field towards the development of cell-based therapies. Here, we provide an overview of the recent progress and future perspectives in the use of AM- and AF-derived cells for therapeutic applications.
Keywords: 5' nucleotidase; beta1 integrin; endoglin; epidermal growth factor; fibroblast growth factor; Hermes antigen; octamer transcription factor 4; scatter factor; stage specific embryo antigen 4; Thy 1 antigen; tissue scaffold; transcription factor NANOG; transcription factor Sox2; transforming growth factor; acute kidney tubule necrosis; amnion; amnion fluid; bladder injury; brain injury; brain ischemia; cell differentiation; cell transplantation; diabetes mellitus; diaphragm hernia; heart failure; heart infarction; human; leg ischemia; liver cirrhosis; nonhuman; paracrine signaling; Parkinson disease; priority journal; protein expression; pulmonary hypertension; regenerative medicine; review; sciatic nerve injury; skin defect; skin graft; spinal muscular atrophy; stem cell transplantation; therapy effect; tissue engineering; tissue repair

The coordinated radio and infrared survey for high-mass star formation (The CORNISH Survey). I. Survey design - Hoare, M. G.; Purcell, C. R.; Churchwell, E. B.; Diamond, P.; Cotton, W. D.; Chandler, C. J.; Smethurst, S.; Kurtz, S. E.; Mundy, L. G.; Dougherty, S. M.; Fender, R. P.; Fuller, G. A.; et al. (Publications of the Astronomical Society of the Pacific, 2012)
We describe the motivation, design, and implementation of the CORNISH survey, an arcsecondresolution radio continuum survey of the inner galactic plane at 5 GHz using the Very Large Array (VLA). It is a blind survey coordinated with the northern Spitzer GLIMPSE I region covering 10° < l < 65° and |b| < 1° at similar resolution. We discuss in detail the strategy that we employed to control the shape of the synthesised beam across this survey, which covers a wide range of fairly low declinations. Two snapshots separated by 4 h kept the beam elongation to less that 1.5 over 75% of the survey area and less than 2 over 98% of the survey. The prime scientific motivation is to provide an unbiased survey for ultra-compact H II regions to study this key phase in massive star formation. A sensitivity around 2 mJy will allow the automatic distinction between radio-loud and radio-quiet mid- IR sources found in the Spitzer surveys. This survey has many legacy applications beyond star formation, including evolved stars, active stars and binaries, and extragalactic sources. The CORNISH survey for compact ionized sources complements other Galactic plane surveys that target diffuse and nonthermal sources, as well as atomic and molecular phases to build up a complete picture of the interstellar medium in the Galaxy.

Flow control in an aggressive inter-turbine duct using low profile vortex generators - Zhang, Yanfeng; Hu, Shuzhen; Zhang, Xue Feng; Benner, Michael; Vlasic, Edward (Turbomachinery, 2012)
This paper presents the experimental investigation of the flow in an aggressive inter-turbine duct (AITD). The goal is to improve the understanding of the flow mechanisms within the AITD and of the underlying physics of lowprofile vortex generators (LPVGs). The flow structures in the AITD are dominated by counter-rotating vortices and boundary layer separations in both the casing and hub regions. At the first bend of the AITD, the casing boundary layer separates in a 3D mode because of the upstream wakes; this is followed by a massive 2D boundary layer separation. Due to the effect of the radial pressure gradient at the first bend, the streamwise vorticity generated by the casing 3D separation stays close to the casing endwall, and later mixes with the casing counter-rotating vortices formed at the second bend. By using LPVGs with different configurations installed on the casing, the casing boundary layer separation is significantly reduced. The streamwise vortices generated by the LPVGs have the potential to generate another pair of counter-rotating vortices at the AITD second bend, which help to delay/prevent the boundary layer separation. Therefore, the total pressure loss in the AITD was significantly reduced.
Keywords: Boundary-layer separation; Casing boundary layer; Counter-rotating vortices; Experimental investigations; Flow mechanisms; Streamwise vortices; Total-pressure loss; Vortex generators; Boundary layers; Ducts; Three dimensional; Transport aircraft; Vortex flow; Gas turbines

Determination of steady state gas turbine operation - Davison, Craig R. (ASME Turbo Expo 2012: Turbine Technical Conference and Exposition, 2012)
Repeatable measurement of engine performance requires the system to be near steady state. A technique is presented to assess how close engine operation is to steady state. It estimates the rate of change of the assessed parameter across the sample time and provides an associated confidence interval. This allows a minimum amount of test time to characterize performance and provides consistent criteria to assess steady state. The technique can either be used online to determine when to take a steady state point or to find the optimal sample from a given data set. To make the technique feasible during testing a recursive method is developed to minimize the computational time. The technique is demonstrated on known functions with random noise to benchmark its capabilities. This is followed by a demonstration on test data from a small turbo jet engine operated in an altitude facility, a turboprop on an outdoor test stand and an after-burning turbofan in an indoor test cell.
Keywords: Computational time; Confidence interval; Engine operations; Engine performance; Indoor test cells; Optimal samples; Recursive methods; Turbine operation; Exhibitions; Jet engines; Gas turbines

Novel controller design demonstration for vibration alleviation of helicopter rotor blades - Ulker, Fatma D.; Nitzscheb, Fred (Active and Passive Smart Structures and Integrated Systems 2012, 2012)
This paper presents an advanced controller design methodology for vibration alleviation of helicopter rotor systems. Particularly, vibration alleviation in a forward ight regime where the rotor blades experience periodically varying aerodynamic loading was investigated. Controller synthesis was carried out under the time-periodic H 2 and H∞ framework and the synthesis problem was solved based on both periodic Riccati and Linear Matrix Inequality (LMI) formulations. The closed-loop stability was analyzed using Floquet-Lyapunov theory, and the controller's performance was validated by closed-loop high-fidelity aeroelastic simulations. To validate the controller's performance an actively controlled trailing edge ap strategy was implemented. Computational cost was compared for both formulations.
Keywords: Advanced controller; Aero-elastic simulations; Aerodynamic loading; Closed loop stability; Computational costs; Controller designs; Controller synthesis; Helicopter vibration control; High fidelity; Linear matrix inequality formulations; Periodic Riccati equation; Synthesis problems; Trailing edges; Integrated control; Linear matrix inequalities; Riccati equations; Turbomachine blades

Rotary wing brown-out symbology: the DVEST test - Jennings, Sion A.; Holst, Peter; Craig, Gregory; Cheung, Bob (Head- and Helmet-Mounted Displays XVII; and Display Technologies and Applications for Defense, Security, and Avionics VI, 2012)
Military helicopter operations encounter degraded visual environments (DVE) on a regular basis. A DVE exists when conditions of low visibility, including those caused by rotor downwash in sand/dust ("brown-out"), snow ("whiteout"/ snowball) or water, obscure both horizon and terrain features. DVE conditions have contributed to the loss of numerous helicopter crews and vehicles in desert operations, including a CH-146 crash during take-off. In Canadian helicopter operations over the past 25 years, "snowball" related events (2 accidents and 54 incidents) outnumbered brown-out related events. A NATO Task Group suggested that specific landing symbology systems could provide an immediate short-term solution that will improve situation awareness and reduce the occurrence of mishaps. This paper describes two symbology systems that were developed and the planned evaluation of these under the Degraded Visual Environment Solution for TacHel (DVEST) Program.
Keywords: Brown-out; Helicopter operation; Low visibility; Night vision goggles; Rotary wing; Short-term solutions; Situation awareness; Symbology; Task groups; Terrain features; Visual environments; Accidents; Helmet mounted displays; Landing; Military helicopters; Visibility; Helicopter services

Water ingress detection in honeycomb sandwich panels by passive infrared thermography using a high-resolution thermal imaging camera - Ibarra-Castanedo, C.; Brault, L.; Marcotte, F.; Genest, M.; Farley, V.; Maldague, X. (Thermosense: Thermal Infrared Applications XXXIV, 2012)
Water ingress in honeycomb structures is of great concern for the civil and military aerospace industries. Pressure and temperature variations during take-off and landing produce considerable stress on aircraft structures, promoting moisture ingress (by diffusion through fibers or by direct ingress through voids, cracks or unsealed joints) into the core. The presence of water (or other fluids such as kerosene, hydraulic fluid and de-icing agents) in any of its forms (gas vapor, liquid or ice) promotes corrosion, cell breakage, and induce composite layer delaminations and skin disbonds. In this study, testing specimens were produced from unserviceable parts from military aircraft. In order to simulate atmospheric conditions during landing, selected core areas were filled with measured quantities of water and then frozen in a cold chamber. The specimens were then removed from the chamber and monitored for over 20 minutes as they warm up using a cooled high-resolution infrared camera. Results have shown that detection and quantification of water ingress on honeycomb sandwich structures by passive infrared thermography is possible using a HD mid-wave infrared cameras for volumes of water as low as 0.2 ml and from a distance as far as 20 m from the target.
Keywords: Aircraft structure; Atmospheric conditions; Composite layer; Core area; De-icing agents; High resolution; Honeycomb sandwich panels; Honeycomb sandwich structure; Infra-red cameras; Mid wave infrared (MWIR); Military aerospace industry; Moisture ingress; Presence of water; Pressure and temperature; Thermal imaging cameras; Water ingress detection; Aerospace industry; Aircraft manufacture; Airframes; Diffusion in liquids; Honeycomb structures; Infrared devices; Infrared radiation; Landing; Nanocomposite films; Sandwich structures; Temperature indicating cameras; Vapors; Thermography (imaging)

CASTOR: the cosmological advanced survey telescope for optical and ultraviolet research - Côte, Patrick; Scott, Alan; Balogh, Michael; Buckingham, Ron; Aldridge, David; Carlberg, Ray; Chen, Weiguo; Dupuis, Jean; Evans, Clinton; Drissen, Laurent; Fraser, Wes; Grandmont, Frederic; et al. (Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, 2012)
The Cosmological Advanced Survey Telescope for Optical and UV Research (CASTOR) is a proposed CSA mission that would make a unique, powerful, and lasting contribution to astrophysics by providing panoramic, high-resolution imaging in the UV/optical (0.15 { 0.55 μm) spectral region. This versatile ̀smallSAT'-class mission would far surpass any ground-based optical telescope in terms of angular resolution, and would provide ultra-deep imaging in three broad filters to supplement longer-wavelength data from planned international dark energy missions (Euclid, WFIRST) as well as from the ground-based Large Synoptic Survey Telescope (LSST). Combining the largest focal plane ever own in space, with an innovative optical design that delivers HST-quality images over a field two orders of magnitude larger than Hubble Space Telescope (HST), CASTOR would image about 1/8th of the sky to a (u-band) depth ̃1 magnitude fainter than will be possible with LSST even after a decade of operations. No planned or proposed astronomical facility would exceed CASTOR in its potential for discovery at these wavelengths.
Keywords: Angular resolution; Dark energy; Focal Plane; Ground based; High-resolution imaging; Hubble space telescopes; Large synoptic survey telescopes; Orders of magnitude; Spectral region; Ultra-violet; Astrophysics; Millimeter waves; Optical design; Space telescopes; Surveys; Optical telescopes

Reference design of deformable mirror electronics for ELT systems - Caputa, Kris; Herriot, Glen; Niebergal, Joel; Zielinski, Adam (Adaptive Optics Systems III, 2012)
One of the first ELT AO systems to be deployed will be NFIRAOS of the Thirty Meter Telescope (TMT). NFIRAOS is currently being designed at the National Research Council of Canada's Herzberg Institute of Astrophysics (HIA). NFIRAOS incorporates deformable mirrors with much larger number of actuators than in current AO systems. To aid the procurement of electronics for NFIRAOS DMs, a reference design is under way at the HIA. We have designed the overall architecture, defined a command communication interface and developed a compact and cost-efficient high voltage amplifier suitable for duplicating in 7673 copies for driving the two NFIRAOS DMs.
Keywords: Deformable mirrors; ELT; High voltage amplifier; NFIRAOS; TMT; Astrophysics; Piezoelectric actuators; Voltage regulators; Laser pulses

Maximization of signal-to-noise ratio in optical coherence tomography using a depth-dependent matched filter - Boroomand, Ameneh; Smith, Michael S. D.; Popescu, Dan P.; Sowa, Michael; Sherif, Sherif S. (Photonics North 2012, 2012)
We discuss and demonstrate the dependence of noise on the signal in time-domain optical coherence tomography (TD-OCT). We then derive a depth-dependent matched filter to maximize the signal-to-noise ratio at every pixel in a depth-scan (A-scan). We use an empirical estimate of the second order statistics of the noise in OCT images of vascular tissue to implement a depth-dependent filter that is matched to these images. The application of our filter results in an average increase of signal-to-noise ratio of about 7 dB compared to a simple averaging operation. Our filter is not specific to time-domain OCT, but it is applicable to other types of OCT systems.
Keywords: Depth dependents; Empirical estimate; OCT images; Second order statistics; Time domain; Vascular tissue; Matched filters; Signal to noise ratio; Tissue; Optical tomography

Towards the simultaneous monitoring of load and damage in aircraft structures using fiber Bragg grating sensors - Xiao, Gaozhi; Guo, Honglei; Mrad, Nezih; Rocha, Bruno; Sun, Zhigang (OFS2012 22nd International Conference on Optical Fiber Sensors, 2012)
Load monitoring and damage detection are the two critical aspects of aircraft structural health monitoring (SHM). The load monitoring is achieved by detecting the local strain changes while the damage detection is generally accomplished by the monitoring of acoustic signal changes. It would be ideal that a single sensor can perform both tasks simultaneously. This paper reports the demonstration of using fiber Bragg gratings to monitor load and acoustic signal applied on a simulated aircraft structure. The results clearly show that a single fiber Bragg grating sensor with short grating length has the potential to perform both tasks simultaneously.

Ukpik: testbed for a miniaturized robotic astronomical observatory on a High Arctic mountain - Steinbring, Eric; Leckie, Brian; Hardy, Tim; Caputa, Kris; Fletcher, Murray (Ground-based and Airborne Telescopes IV, 2012)
Mountains along the northwestern coast of Ellesmere Island, Canada, possess the highest peaks nearest the Pole. This geography, combined with an atmospheric thermal inversion restricted to below ∼1000 m during much of the long arctic night, provides excellent opportunities for uninterrupted cloud-free astronomy - provided the challenges of these incredibly remote locations can be overcome. We present a miniaturized robotic observatory for deployment on a High Arctic mountaintop. This system tested the operability of precise optical instruments during winter, and the logistics of installation and maintenance during summer. It is called Ukpik after the Inuktitut name for the snowy owl, and was deployed at two sites accessible only by helicopter, each north of 82 degrees latitude; one on rock at 1100 m elevation and another on a glacier at 1600 m. The instrument suite included at first an all-sky-viewing camera, with the later addition of a small telescope to monitor Polaris, both protected by a retractable weather-proof enclosure. Expanding this to include a narrow-field drift-scanning camera for studying extra-solar planet transits was also investigated, but not implemented. An unique restriction was that all had to be run on batteries recharged primarily by a wind turbine. Supplementary power came from a methanol fuel-cell electrical generator. Communications were via the Iridium satellite network. The system design, and lessons learned from three years of operation are discussed, along with prospects for time-domain astronomy from isolated, high-elevation polar mountaintops.

Opacity measurements at Summit Camp on Greenland and PEARL in Northern Canada with a 225 GHz tipping radiometer - Asada, Keiichi; Martin-Cocher, Pierre L.; Chen, Chien-Ping; Matsushita, Satoki; Chen, Ming-Tang; Huang, Yau-De; Inoue, Makoto; Ho, Paul T. P.; Paine, Scott N.; Steinbring, Eric (Ground-based and Airborne Telescopes IV, 2012)
We report the first measurements of 225 GHz atmospheric opacity at Summit Camp (Latitude 72°.57 N; Longitude 38°.46 W; Altitude 3250 m) in Greenland and the Polar Environment Atmospheric Research Laboratory (PEARL: Latitude 80°.05 N; Longitude 86°.42 W; Altitude 600 m) in Northern Canada with a tipping radiometer. Summit Camp and PEARL are research stations mostly interested in meteorology and geophysics, and they are potentially excellent sites for astronomical observations at sub-millimeter wavelength. We purchased a tipping radiometer from Radiometer Physics GmbH. After a test run at the summit of Mauna Kea, Hawaii, the radiometer was deployed to PEARL in February 2011, and relocated to Summit Camp in August 2011. The atmospheric opacity has been monitored from February 14th to May 10th, 2011 at PEARL and since August 2011 at Summit Camp. The median values of the measured opacity at PEARL ranged from 0.11 in February to 0.19 in May; Summit Camp varied in the range from 0.04 to 0.18 between August 2011 and May 2012. Summit Camp in Greenland is expected to be an excellent site for sub-millimeter and Terahertz astronomy, and we plan to set up there a 12-m telescope for VLBI and single-dish observations.

Haptics-based immersive telerobotic system for improvised explosive device disposal: Are two hands better than one? - Erickson, David; Lacheray, Hervé; Lambert, Jason Michel; Mantegh, Iraj; Crymble, Derry; Daly, John; Zhao, Yan (Unmanned Systems Technology XIV, 2012)
State-of-the-art robotic explosive ordnance disposal robotics have not, in general, adopted recent advances in control technology and man-machine interfaces and lag many years behind academia. This paper describes the Haptics-based Immersive Telerobotic System project investigating an immersive telepresence envrionment incorporating advanced vehicle control systems, Augmented immersive sensory feedback, dynamic 3D visual information, and haptic feedback for explosive ordnance disposal operators. The project aim is to provide operatiors a more sophisticated interface and expand sensory input to perform complex tasks to defeat improvised explosive devices successfully. The introduction of haptics and immersive teleprescence has the potential to shift the way teleprescence systems work for explosive ordnance disposal tasks or more widely for first responders scenarios involving remote unmanned ground vehicles.

On the use of a compact optical fiber sensor system in aircraft structural health monitoring - Mrad, Nezih; Guo, Honglei; Xiao, Gaozhi; Rocha, Bruno; Sun, Zhigang (Photonic Applications for Aerospace, Transportation, and Harsh Environment III, 2012)
Structural Health Monitoring (SHM) has been identified as an area of significant potential for advanced aircraft maintenance programs that ensure continued airworthiness, enhanced operational safety and reduced life cycle cost. Several sensors and sensory systems have been developed for the implementation of such health monitoring capability. Among a wide range of developed technologies, fiber optic sensor technology, in particular fiber Bragg grating based emerged as one of the most promising for aircraft structural applications. This paper is set to explore the suitability of using a new Fiber Bragg Grating sensor (FBG) system developed for operation in two modes, low and high speed sensing modes, respectively. The suitability of the system for potential use in aircraft load monitoring and damage detection applications has been demonstrated. Results from FBG sensor system were in good agreement with results from conventional resistive strain gauges, validating this capability for load monitoring. For damage detection, the FBG sensor system was able to detect acoustic waves generated 52 inches (1.32 m) away. The initial results, obtained in a full stale experimentation, demonstrate the potential of using FBG sensors for both load monitoring and damage detection in aircraft environment.

TMT adaptive optics program status report - Ellerbroek, Brent L.; Adkins, Sean M.; Andersen, David R.; Atwood, Jenny; Bastard, Arnaud; Bo, Yong; Boucher, Marc-Andre; Boyer, Corinne; Byrnes, Peter W. G.; Caputa, Kris; Chen, Shanqiu; Correia, Carlos; et al. (Adaptive Optics Systems III, 2012)
We provide an update on the development of the first light adaptive optics systems for the Thirty Meter Telescope (TMT) over the past two years. The first light AO facility for TMT consists of the Narrow Field Infra-Red AO System (NFIRAOS) and the associated Laser Guide Star Facility (LGSF). This order 60 x 60 laser guide star (LGS) multi-conjugate AO (MCAO) architecture will provide uniform, diffraction-limited performance in the J, H, and K bands over 17-30 arc sec diameter fields with 50 per cent sky coverage at the galactic pole, as is required to support TMT science cases. Both NFIRAOS and the LGSF have successfully completed design reviews during the last twelve months. We also report on recent progress in AO component prototyping, control algorithm development, and system performance analysis. © 2012 SPIE.

Characterizing near-infrared sky brightness in the Canadian high arctic - Sivanandam, Suresh; Graham, James R.; Abraham, Roberto; Tekatch, Anthony; Steinbring, Eric; Ngan, Wayne; Welch, Doug L.; Law, Nicholas M. (Ground-based and Airborne Instrumentation for Astronomy IV, 2012)
We present the first measurements of the near-infrared (NIR), specifically the J-band, sky background in the Canadian High Arctic. There has been considerable recent interest in the development of an astronomical observatory in Ellesmere Island; initial site testing has shown promise for a world-class site. Encouragement for our study came from sky background measurements on the high Antarctic glacial plateau in winter that showed markedly lower NIR emission when compared to good mid-latitude astronomical sites due to reduced emission from the Meinel bands, i.e. hydroxyl radical (OH) airglow lines. This is possibly a Polar effuect and may also be present in the High Arctic. To test this hypothesis, we carried out an experiment which measured the the J-band sky brightness in the High Arctic during winter. We constructed a zenith-pointing, J-band photometer, and installed it at the Polar Environment Atmospheric Research Laboratory (PEARL) near Eureka, Nunavut (latitude: 80° N). We present the design of our ruggedized photometer and our results from our short PEARL observing campaign in February 2012. Taken over a period of four days, our measurements indicate that the J-band sky brightness varies between 15:5-15:9 mag arcsec2; with a measurement uncertainty of 0.15 mag. The uncertainty is entirely dominated by systematic errors present in our radiometric calibration. On our best night, we measured a fairly consistent sky brightness of 15:8 ± 0:15 mag arcsec2: This is not corrected for atmospheric extinction, which is typically < 0:1 mag in the J-band on a good night. The measured sky brightness is comparable to an excellent mid-latitude site, but is not as dark as claimed by the Antarctic measurements. We discuss possible explanations of why we do not see as dark skies as in the Antarctic. Future winter-long sky brightness measurements are anticipated to obtain the necessary statistics to make a proper comparison with the Antarctic measurements.

A Fresnel propagation analysis of NFIRAOS/IRIS high-contrast exoplanet imaging capabilities - Marois, Christian; Véran, Jean-Pierre; Correia, Carlos (Adaptive Optics Systems III, 2012)
The thirty meter telescope (TMT) has the potential to find new planetary systems and to study them in greater details. It could also possibly image super-Earth planets around the closest stars or still accreting distant protoplanets around stars in very young star forming regions. Since no first generation dedicated exoplanet finding instrument has been selected for the TMT, initial direct exoplanet imaging will have to rely on the NFIRAOS facility adaptive optics (AO) system and IRIS spectro-imaging near-infrared (NIR) camera. End-to-end Fresnel NFIRAOS simulations are presented using their current optical designs to evaluate the system multi-wavelength high-contrast imaging capabilities. Long exposures have been simulated using the expected AO-corrected phase screens and the estimated speckle lifetime. It is shown that NFIRAOS/IRIS may achieve contrasts close to the Gemini planet imager (GPI, an optimized NIR planet-finding instrument that will soon be installed on the Gemini South 8-m telescope), but needs to rely on multi-wavelength processing (by a factor 50) to achieve that goal, a challenging requirement. Without a coronograph and a better treatment of the in-band static speckle noise, it is unlikely that NFIRAOS/IRIS will be able to achieve GPI-like contrasts at very small inner working angles, which is potentially accessible with a large 30-meter telescope. However, TMT, with its bigger aperture and better angular resolution, along with the current NFIRAOS/IRIS designs, should be able to acquire higher SNR spectra and achieve three times better astrometric accuracy than GPI for medium to bright planets, resulting in better atmospheric characterization and faster orbital parameter determination of a sample of GPI planets.

Polymer Nanomechanics - Li, J. K.; Li, I. T. S.; Walker, G. C.; Sullan, R. M. A.; Zou, S.; Sun, Y. (Polymer Science: A Comprehensive Reference, 2012)
The objective of studying the nanoscale mechanical properties and behavior of polymers is to understand how polymeric organized nanostructures respond to forces applied in tension, in compression, and even during fracture. The body of work presented in this review is primarily from our laboratories and covers a breadth of systems and techniques, including atomic force microscopy-based indentation studies on substrate-supported polymeric thin films, microscale hydrogels, force-mapping studies on lipid bilayers, and the mechanics of hydrophobic polymer hydration by single-molecule extension. The elastic response, the contribution of mechanical restructuring, viscosity, and other dissipative effects, as well as interfacial forces, are investigated.
Keywords: Adhesion; Atomic force microscopy; Elasticity; Force curve; Force mapping; Hydrophobic hydration; Indentation; Interfacial energy; Microgels; Planar-supported lipid bilayers; Polymer mechanics; Single-molecule force spectroscopy; Viscoelasticity; Young’s modulus

Guillain-Barré syndrome-related Campylobacter jejuni in Bangladesh: ganglioside mimicry and cross-reactive antibodies - Islam, Zhahirul; Gilbert, Michel; Mohammad, Quazi D.; Klaij, Kevin; Li, Jianjun; van Rijs, Wouter; Tio-Gillen, Anne P.; Talukder, Kaisar A.; Willison, Hugh J.; van Belkum, Alex; Endtz, Hubert P.; Jacobs, Bart C. (PLoS ONE, 2012)
Background: Campylobacter jejuni is the predominant antecedent infection in Guillain-Barré syndrome (GBS). Molecular mimicry and cross-reactive immune responses to C. jejuni lipo-oligosaccharides (LOS) precipitate the development of GBS, although this mechanism has not been established in patients from developing countries. We determined the carbohydrate mimicry between C. jejuni LOS and gangliosides, and the cross-reactive antibody response in patients with GBS in Bangladesh. Methodology: Sera from 97 GBS patients, and 120 neurological and family controls were tested for antibody reactivity against LOS from C. jejuni isolates from GBS patients in Bangladesh (BD-07, BD-39, BD-10, BD-67 and BD-94) by enzyme-linked immunosorbent assay (ELISA). Cross-reactivity to LOS was determined by ELISA. The LOS outer core structures of C. jejuni strains associated with GBS/MFS were determined by mass spectrometry. Principle Findings: IgG antibodies to LOS from C. jejuni BD-07, BD-39, BD-10, and BD-67 IgG antibodies were found in serum from 56%, 58%, 14% and 15% of GBS patients respectively, as compared to very low frequency (<3%) in controls (p<0.001). Monoclonal antibodies specific for GM1 and GD1a reacted strongly with LOS from the C. jejuni strains (BD-07 and BD-39). Mass spectrometry analysis confirmed the presence of GM1 and GD1a carbohydrate mimics in the LOS from C. jejuni BD-07 and BD-39. Both BD-10 and BD-67 express the same LOS outer core, which appears to be a novel structure displaying GA2 and GD3 mimicry. Up to 90-100% of serum reactivity to gangliosides in two patients (DK-07 and DK-39) was inhibited by 50 μg/ml of LOS from the autologous C. jejuni isolates. However, patient DK-07 developed an anti-GD1a immune response while patient DK-39 developed an anti-GM1 immune response. Conclusion: Carbohydrate mimicry between C. jejuni LOS and gangliosides, and cross-reactive serum antibody precipitate the majority of GBS cases in Bangladesh.
Keywords: antibodies; Campylobacter; enzyme-linked immunoassays; immune response; glycosyltransferases; molecular mimicry; monoclonal antibodies; serology

Ultrafast photocurrent measurement of the escape time of electrons and holes from carbon nanotube p-i-n photodiodes - Gabor, Nathaniel M.; Zhong, Zhaohui; Bosnick, Ken; McEuen, Paul L. (Physical Review Letters, 2012)
Ultrafast photocurrent measurements are performed on individual carbon nanotube p-i-n photodiodes. The photocurrent response to subpicosecond pulses separated by a variable time delay Δt shows strong photocurrent suppression when two pulses overlap (Δt=0). The picosecond-scale decay time of photocurrent suppression scales inversely with the applied bias VSD, and is twice as long for photon energy above the second subband E22 as compared to lower energy. The observed photocurrent behavior is well described by an escape time model that accounts for carrier effective mass.
Keywords: Applied bias; Carrier effective mass; Decay time; Electrons and holes; Escape time; Lower energies; Photocurrent measurement; Photocurrent response; Photon energy; Pin photodiode; Sub-bands; Subpicosecond pulse; Ultra-fast; Variable time delay; Carbon nanotubes; Photodiodes; Photocurrents

Electron-ion and ion-ion potentials for modeling warm dense matter: applications to laser-heated or shock-compressed Al and Si - Dharma-Wardana, M. W. C. (Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 2012)
The pair interactions Uij(r) determine the thermodynamics and linear transport properties of matter via the pair-distribution functions (PDFs), i.e., gij(r). Great simplicity is achieved if Uij(r) could be directly used to predict material properties via classical simulations, avoiding many-body wave functions. Warm dense matter (WDM) is encountered in quasiequilibria where the electron temperature Te differs from the ion temperature Ti, as in laser-heated or in shock-compressed matter. The electron PDFs g ee(r) as perturbed by the ions are used to evaluate fully nonlocal exchange-correlation corrections to the free energy, using hydrogen as an example. Electron-ion potentials for ions with a bound core are discussed with Al and Si as examples, for WDM with Te≠Ti, and valid for times shorter than the electron-ion relaxation time. In some cases the potentials develop attractive regions and then become repulsive and "Yukawa-like" for higher Te. These results clarify the origin of initial phonon hardening and rapid release. Pair potentials for shock-heated WDM show that phonon hardening would not occur in most such systems. Defining meaningful quasiequilibrium static transport coefficients consistent with the dynamic values is addressed. There seems to be no meaningful "static conductivity" obtainable by extrapolating experimental or theoretical σ(ω,Ti,Te) to ω→0, unless Ti→Te as well. Illustrative calculations of quasistatic resistivities R(Ti,Te) of laser-heated as well as shock-heated aluminum and silicon are presented using our pseudopotentials, pair potentials, and classical integral equations. The quasistatic resistivities display clear differences in their temperature evolutions, but are not the strict ω→0 limits of the dynamic values.
Keywords: Attractive Region; Classical simulation; Electron ions; Exchange-correlation correction; Higher T; Ion temperature; Many body wave functions; Material property; Nonlocal; Pair distribution functions; Pair interactions; Pair potential; Phonon hardening; Pseudopotentials; Quasi-equilibrium; Quasi-static; Rapid release; Static conductivity; Temperature evolution; Transport coefficient; Warm dense matters; Aluminum; Electron temperature; Electrons; Hardening; Hydrogen; Phonons; Silicon; Thermodynamics; Transport properties; Wave plasma interactions

Structural phase transitions in Si under hydrostatic and uniaxial compression - Yao, Yansun; Klug, Dennis D. (Physical Review B - Condensed Matter and Materials Physics, 2012)
Phase transitions induced by hydrostatic and uniaxial compression of Si are examined using a density functional-based metadynamics method. A metastable Cmcm structure is predicted to form under hydrostatic compression at 300 K in the pressure range near 20 GPa. Enthalpy calculations indicate that this new phase of Si is energetically competitive with the other Si structures found in this pressure range. This phase is shown to be dynamically stable, with a structure closely related to that of the β-Sn and Imma structures previously identified in experiments. Uniaxial compression at 15 GPa and 300 K obtained simple hexagonal Imma and β-Sn structures. The low energy barrier for the formation of the Cmcm structure from the diamond ambient pressure form suggests that this structure may be seen in experiment with the proper experimental conditions.

Coherent exchange and double beam splitter oscillations in a triple quantum dot - Aers, G. C.; Studenikin, S. A.; Granger, G.; Kam, A.; Zawadzki, P.; Wasilewski, Z. R.; Sachrajda, A. S. (Physical Review B - Condensed Matter and Materials Physics, 2012)
Recent experiments with an electrostatically gated structure demonstrated coherent oscillations, involving all three spins of a linear triple dot system. In a combined experimental and theoretical study, we demonstrate coherent doublet/doublet exchange oscillations, leading to arbitrary rotation on the relevant Bloch sphere, and we reveal an interplay between exchange and hyperfine-driven "double coherent beam splitter" oscillations.

High-pressure phases of lithium borohydride LiBH4: a first-principles study - Yao, Yansun; Klug, Dennis D. (Physical Review B - Condensed Matter and Materials Physics, 2012)
High-pressure phase transformations in LiBH 4 were theoretically investigated using first-principles density functional methods. A series of pressure-induced structural transformations are predicted in LiBH 4, as Pnma (phase II) → I4 1/acd (phase III) → NaCl type (phase V) → NiAs type (phase VI) → polymeric forms. The calculated pressures for the II → III transition and the III → V transition are 0.9 and 27 GPa, respectively, and both agree very well with recent experimental observations. A B1-B8 transformation becomes more favored at higher pressure, and this results in a distorted NiAs structure of LiBH 4. Denoted as phase VI, the distorted NiAs structure is the lowest enthalpy phase of LiBH 4 above 60 GPa and confirmed to be dynamically stable by phonon calculations. The ionic character and band gap of the phase VI decreases with increasing pressure. At still higher pressures, the extended structures formed by polymeric BH 4 layers intercalated by Liδ + cations may exist, and these represent the metallic forms of LiBH 4. Published by the American Physical Society.

Nonlinear magnetotransport phenomena in high-mobility two-dimensional electrons in InGaAs/InP and GaAs/AlGaAs - Studenikin, S. A.; Granger, G.; Kam, A.; Sachrajda, A. S.; Wasilewski, Z. R.; Poole, P. J. (Physical Review B - Condensed Matter and Materials Physics, 2012)
This paper reports on the observation and analysis of magnetotransport phenomena in the nonlinear differential resistance rxx=dVxx/dI of high-mobility In xGa 1-xAs/InP and GaAs/Al xGa 1-xAs Hall bar samples driven by direct current I dc. Specifically, it is observed that Shubnikov-de Haas (SdH) oscillations at large filling factors invert their phase at sufficiently large values of Idc. This phase inversion is explained as being due to an electron heating effect. In the quantum Hall effect regime the rxx oscillations transform into diamond-shaped patterns with different slopes corresponding to odd and even filling factors. The diamond-shaped features at odd filling factors can be used as a probe to determine spin energy gaps. A zero current anomaly (ZCA) which manifests itself as a narrow dip in the rxx(Idc) characteristics at zero current is also observed. The ZCA effect strongly depends upon temperature, vanishing above 1 K while the transport diamonds persist to higher temperatures. The transport diamonds and ZCA are fully reproduced in a higher mobility GaAs/AlGaAs Hall bar structure confirming that these phenomena reflect intrinsic properties of two-dimensional systems.

Microwave-induced resistance oscillations in tilted magnetic fields - Bogan, A.; Hatke, A. T.; Studenikin, S. A.; Sachrajda, A.; Zudov, M. A.; Pfeiffer, L. N.; West, K. W. (Physical Review B - Condensed Matter and Materials Physics, 2012)
We have studied the effect of an in-plane magnetic field on microwave-induced resistance oscillations in a high mobility two-dimensional electron system. We have found that the oscillation amplitude decays exponentially with an in-plane component of the magnetic field B1. While these findings cannot be accounted for by existing theories, our analysis suggests that the decay can be explained by a B1-induced correction to the quantum scattering rate, which is quadratic in B1.

Molecular alignment and orientation with a hybrid Raman scattering technique - Bustard, Philip J.; Lausten, R.; Sussman, Benjamin J. (Physical Review A - Atomic, Molecular, and Optical Physics, 2012)
We demonstrate a scheme for the preparation of molecular alignment and angular momentum orientation using a hybrid combination of two limits of Raman scattering. First a weak, impulsive pump pulse initializes the system via the nonresonant dynamic Stark effect. Then, having overcome the influence of the vacuum fluctuations, an amplification pulse selectively enhances the initial coherences by transient stimulated Raman scattering, generating alignment and angular momentum orientation of molecular hydrogen. The amplitude and phase of the resulting coherent dynamics are experimentally probed, indicating an amplification factor of 4.5. An analytic theory is developed to model the dynamics.
Keywords: Amplification factors; Analytic theory; Angular momentum orientation; Coherent dynamics; Molecular hydrogen; Nonresonant dynamic Stark effects; Physical societies; Pump pulse; Scattering techniques; Vacuum fluctuations; Amplification; Angular momentum; Optical pumping

Highly tolerant tunable waveguide polarization rotator scheme - Alonso-Ramos, C.; Halir, R.; Ortega-Moñux, A.; Cheben, P.; Vivien, L.; Molina-Fernández, Í.; Marris-Morini, D.; Janz, S.; Xu, D.-X.; Schmid, J. (Optics Letters, 2012)
Integrated polarization rotators are known to exhibit stringent fabrication tolerances, which severely handicap their practical application. Here we present a general polarization rotator scheme that enables both the compensation of fabrication errors and wavelength tunability. The scheme is described analytically, and a condition for perfect polarization conversion is established. Simulations of a silicon-on-insulator polarization rotator show polarization extinction ratios in excess of 40 dB even in the presence of large fabrication errors that in a conventional rotator configuration degrade the extinction ratio to below 5 dB. Additionally, wavelength tuning over ±30 nm is shown.
Keywords: Extinction ratios; Fabrication errors; Fabrication tolerances; Polarization conversion; Polarization extinction ratio; Polarization rotator; Silicon on insulator; Tunable wave-guides; Wavelength tunability; Wavelength tuning; Errors; Fabrication; Optical communication