ZnMn2O4 nanoparticles synthesized by a hydrothermal method as an anode material for Li-ion batteries - Courtel, Fabrice M.; Abu-Lebdeh, Yaser; Davidson, Isobel J. (Electrochimica Acta, 2012)
ZnMn2O4 nanoparticles prepared by a hydrothermal synthesis were evaluated as anode material for Li-ion batteries. XRD measurements showed that a ZnMn2O4 I41/amd tetragonal spinel structure was obtained with crystallite sizes ≤5 nm. TEM micrographs showed that particles of about 5 nm in diameter were synthesized. Li/ZnMn2O4 half cell battery cycling showed that the nanoparticles, using lithium salt of carboxymethylcellulose as binder, give a high capacity of 430 mAh g−¹ when cycled 100 times at C/10.
Keywords: ZnMn2O4; Hydrothermal; Li-ion batteries; Nanoparticles; Anode material

Titanium carbide and its core-shelled derivative TiC@TiO2 as catalyst supports for proton exchange membrane fuel cells - Ignaszak, Anna; Song, Chaojie; Zhu, Weimin; Zhang, Jiujun; Bauer, Alex; Baker, Ryan; Neburchilov, Vladimir; Ye, Siyu; Campbell, Stephen (Electrochimica Acta, 2012)
Both TiC and core-shelled TiC@TiO2 are investigated as catalyst supports for proton exchange membrane fuel cells (PEMFCs). TiC is thermally stable, possesses both low solubility in sulphuric acid and high electronic conductivity. However, TiC undergoes irreversible electrochemical oxidation in dilute perchloric acid and the operating potential range of 0–1.2 VRHE. TiC@TiO2 core–shell composite is found to be more stable than TiC. Both these materials are used as supports for Pt and Pt–Pd alloy catalysts (Pt/TiC, Pt3Pd/TiC and Pt3Pd/TiC@TiO2) and are synthesized by microwave-assisted polyol process. The catalytic activities of both Pt3Pd/TiC and Pt3Pd/TiC@TiO2 toward the oxygen reduction reaction (ORR) are much higher than those for Pt/TiC. Accelerated durability tests show that TiC supported catalysts are not electrochemically stable. The corresponding TiC@TiO2 supported catalyst is more stable than that supported by TiC, indicating that with a protective oxide layer on the TiC core, TiC@TiO2 is a promising PEMFC catalyst support.
Keywords: Catalyst support; Titanium carbide; Core–shell structure; Pt and Pt–Pd alloy catalysts; Proton exchange membrane fuel cells

Experimental measurement of effective diffusion coefficient of gas diffusion layer/microporous layer in PEM fuel cells - Chan, Carl; Zamel, Nada; Li, Xianguo; Shen, Jun (Electrochimica Acta, 2012)
Accuracy in the effective diffusion coefficient of the gas diffusion layer (GDL)/microporous layer (MPL) is important to accurately predict the mass transport limitations for high current density operation of polymer electrolyte membrane (PEM) fuel cells. All the previous studies regarding mass transport limitations were limited to pure GDLs, and experimental analysis of the impact of the MPL on the overall diffusion in the porous GDL is still lacking. A modified Loschmidt cell with an oxygen–nitrogen mixture is used in this work to determine the effect of MPL on the effective diffusion coefficients. It is found that Knudsen effects play a dominant role in the diffusion through the MPL where pore diameters are less than 1 μm. Experimental results show that the effective diffusion coefficient of the MPL is only about 21% that of its GDL substrate and Knudsen diffusion accounts for 80% of the effective diffusion coefficient of the GDL with MPL measured in this study. No existing correlations can correlate the effective diffusion coefficient with significant Knudsen contribution.
Keywords: Diffusion; Porous media; Fuel cell; Carbon paper; Gas diffusion layer; Microporous layer; Diffusion coefficient; Knudsen effect; Loschmidt cell

Cyclic oxidation behavior of a beta gamma powder metallurgy TiAl–4Nb–3Mn alloy coated with a NiCrAlY coating - Kim, D.J.; Seo, D.Y.; Huang, X.; Yang, Q.; Kim, Y.-W. (Surface and Coatings Technology, 2012)
A new beta gamma TiAl–4Nb–3Mn alloy was synthesized by powder metallurgy (PM) and coated with NiCrAlY powder by Air Plasma Spray (APS). The cyclic oxidation behavior of the coated beta gamma alloy was investigated between room temperature and 1000 °C for up to 800 cycles. During cyclic oxidation testing, a TiN layer formed at the interface between NiCrAlY and TiAl–4Nb–3Mn and the thickness of the TiN layer increased with the number of cycles. The outward Ti diffusion also resulted in the formation of titanium oxides on the coating top surface after 630 cycles. Inward diffusion of Ni led to the formation of an inner diffusion zone containing NiAlTi and a mixture of NiAlTi + TiAl. Due to the spallation of coating scales on the circumferential surface, weight loss was observed after 120 cycles although both the top and bottom surfaces of the specimens remain in contact with the substrate until 800 cycles. Due to inward and outward diffusion, half of the NiCrAlY coating was consumed after 800 cycles suggesting the need for diffusion barrier coating at the interface between the NiCrAlY coating and the TiAl–4Nb–3Mn alloy.
Keywords: Titanium aluminide; Beta gamma alloys; NiCrAlY; Plasma spray; Powder metallurgy; Cyclic oxidation

Effects of electrode layer composition/thickness and electrolyte concentration on both specific capacitance and energy density of supercapacitor - Tsay, Keh-Chyun; Zhang, Lei; Zhang, Jiujun (Electrochimica Acta, 2012)
In this paper, the effects of several experimental conditions, such as electrode layer binder content, conducting carbon content, electrode layer thickness, as well as electrolyte concentration, on both the specific capacitance and energy density of a BP2000 carbon-based supercapacitor are investigated using both cyclic voltammetry and a galvanic charging–discharging curve. The electrode layer studied contains Super C45 carbon as the conducting additive, PTFE as the binder, and Na2SO4 as the aqueous electrolyte, respectively. With the purpose of optimizing the electrode layer structure, 15 wt% of Super C45 and 5 wt% of PTFE in the electrode layer with a thickness of 100 μm, are found to be the best composition in terms of improving both specific capacitance and energy density. Regarding the effect of electrolyte concentration in the range of 0.1–1.0 M, 0.5 M of Na2SO4 gives the best performance.

Diffusion abnormality maps in demyelinating disease: correlations with clinical scores - Onu, Mihaela; Roceanu, Adina; Sboto-Frankenstein, Uta; Bendic, Robert; Tarta, Eugen; Preoteasa, Florentin; Bajenaru, Ovidiu (European Journal of Radiology, 2012)
Background and purpose - Magnetic resonance imaging (MRI) has been explored as a noninvasive tool to assess pathology in multiple sclerosis (MS) patients. However, the correlation between classical MRI measures and physical disability is modest in MS. The diffusion tensor imaging (DTI) MRI technique holds particular promise in this regard. The present study shows brain regions where FA and individual diffusivities abnormalities are present and check their correlations with physical disability clinical scores. Methods - Eight patients and 12 matched healthy controls were recruited. The Multiple Sclerosis Functional Composite was administered. For MR-DTI acquisitions, a Genesis Signa 1.5T MR system, an EP/SE scanning sequence, 25 gradient directions were used. Results - Tract Based Spatial Statistics (TBSS) group comparisons showed reduced FA and increased individual diffusivities in several brain regions in patients. Significant correlations were found between FA and: EDSS, 9-HPT(NON)DOM and 25FW score; between λ2 and: P100 (r&l), 9-HPT(NON)DOM and 25FW; between λ3 and: 9-HPT(NON)DOM and 25FW score. Conclusions - Fractional anisotropy and individual radial diffusivities proved to be important markers of motor disabilities in MS patients when the disease duration mean and the disability scores values range are relatively high.
Keywords: Diffusion tensor imaging; TBSS; Multiple sclerosis

Single domain antibody against carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) inhibits proliferation, migration, invasion and angiogenesis of pancreatic cancer cells - Cheng, Tsai-Mu; Murad, Yanal M.; Chang, Chia-Ching; Yang, Ming-Chi; Baral, Toya Nath; Cowan, Aaron; Tseng, Shin-Hua; Wong, Andrew; Mackenzie, Roger; Shieh, Dar-Bin; Zhang, Jianbing (European Journal of Cancer, 2012)
Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) is over-expressed in pancreatic cancer cells, and it is associated with the progression of pancreatic cancer. We tested a single domain antibody (sdAb) targeting CEACAM6, 2A3, which was isolated previously from a llama immune library, and an Fc conjugated version of this sdAb, to determine how they affect the pancreatic cancer cell line BxPC3. We also compared the effects of the antibodies to gemcitabine. Gemcitabine and 2A3 slowed down cancer cell proliferation. However, only 2A3 retarded cancer cell invasion, angiogenesis within the cancer mass and BxPC3 cell MMP-9 activity, three features important for tumour growth and metastasis. The IC50s for 2A3, 2A3-Fc and gemcitabine were determined as 6.5 μM, 8 μM and 12 nM, respectively. While the 2A3 antibody inhibited MMP-9 activity by 33% compared to non-treated control cells, gemcitabine failed to inhibit MMP-9 activity. Moreover, 2A3 and 2A3-Fc inhibited invasion of BxPC3 by 73% compared to non-treated cells. When conditioned media that were produced using 2A3- or 2A3-Fc-treated BxPC3 cells were used in a capillary formation assay, the capillary length was reduced by 21% and 49%, respectively. Therefore 2A3 is an ideal candidate for treating tumours that over-express CEACAM6.
Keywords: CEACAM6; Single domain antibodies; Pancreatic cancer; Gemcitabine; Angiogenesis; MMP-9; BxPC3

An upper limit on the lateral vacancy diffusion length in diamond - Orwa, J. O.; Ganesan, K.; Newnham, J.; Santori, C.; Barclay, P.; Fu, K. M. C.; Beausoleil, R. G.; Aharonovich, I.; Fairchild, B. A.; Olivero, P.; Greentree, A. D.; Prawer, S. (Diamond and Related Materials, 2012)
Ion implantation is widely used to modify the structural, electrical and optical properties of materials. By appropriate masking, this technique can be used to define nano- and micro-structures. However, depending on the type of mask used, experiments have shown that vacancy-related substrate modification can be inferred tens of micrometers away from the edge of the mask used to define the implanted region. This could be due to fast diffusion of vacancies from the implanted area during annealing or to a geometric effect related to ion scattering around the mask edges. For quantum and single-atom devices, stray ion damage can be deleterious and must be minimized. In order to profile the distribution of implantation-induced damage, we have used the nitrogen-vacancy color center as a sensitive marker for vacancy concentration and distribution following MeV He ion implantation into diamond and annealing. Results show that helium atoms implanted through a mask clamped to the diamond surface are scattered underneath the mask to distances in the range of tens of micrometers from the mask edge. Implantation through a lithographically defined and deposited mask, with no spacing between the mask and the substrate, significantly reduces the scattering to ≤ 5 μm but does not eliminate it. These scattering distances are much larger than the theoretically estimated vacancy diffusion distance of ~ 260 nm under similar conditions. This paper shows that diffusion, upon annealing, of vacancies created by ion implantation in diamond, is limited, and the appearance of vacancies many tens of micrometers from the edge of the mask is due to scattering effects.
Keywords: Ion implantation; Annealing; Vacancy diffusion; Scattering

A bench scale study of removal of cyclohexane and naphtha components from water by membrane air-stripping process - Mahmud, Hassan; Kumar, Ashwani (Desalination, 2012)
Removal of hazardous chemicals such as cyclohexane and naphtha components from water with air-stripping (MAS) technique using a polypropylene microporous hollow fiber module is reported. The mass transfer of these organics through the membrane from the water on the feed side to the air stream on the permeate side was evaluated under different experimental conditions in a batch system. Removal of cyclohexane as well as naphtha components by MAS process for the investigated experimental conditions appears to be promising. It was observed in separate experiments that the concentrations of cyclohexane and naphtha components in water were significantly reduced by the MAS process.
Keywords: Cyclohexane; Naphtha; Organics removal; Hollow fiber; Contactor; Membrane air stripping

Effect of hormone implantation on cryopreservation of Atlantic halibut (Hippoglossus hippoglossus L.) sperm - Ding, Fuhong; Milley, Joyce E.; Rommens, Melissa; Li, Jun; Lei, Jilin; Lall, Santosh P. (Cryobiology, 2012)
Hormone implantation is widely applied in halibut (Hippoglossus hippoglossus L.) aquaculture to extend the sperm production season of broodstock males. The ability to combine this technique with cryopreservation would increase sperm availability, thereby improving reproduction success and facilitating gene management. In this paper, the cryopreservation ability of sperm from hormone-treated males was examined at three times post-implantation and compared with that of sperm from males that were not hormone-treated. All sperm samples were cryopreserved using the same method. The effectiveness of these techniques was assessed by examining the fertilization rate and motility of thawed sperm. The spermotocrit and concentration of fresh sperm samples were measured to reveal the effect of hormone implantation on sperm characteristics. The reported results indicate that hormone implantation did not affect cryopreservation efficiency. The fertilization rate resulting from thawed sperm of hormone-treated males showed no significant difference from that of untreated males or from fresh sperm. A significant positive relationship was demonstrated between the spermatocrit and concentration of sperm; and a significant decrease of spermatocrit was found in sperm collected from hormone-treated males 14 days post-implantation. No significant linear relationship between spermotocrit and fertilization rate of thawed sperm was shown.
Keywords: Atlantic halibut (Hippoglossus hippoglossus L.); Hormone (GnRHa); Cryopreservation; Spermotocrit; Fertilization

Electronic structure of a single MoS2 monolayer - Kadantsev, Eugene S.; Hawrylak, Pawel (Solid State Communications, 2012)
The electronic structure of a single MoS2 monolayer is investigated with all electron first-principles calculations based on Kohn Sham Density Functional Theory and variational treatment of spin–orbital coupling. The topologies of the valence band maximum and conduction band minimum are explored over the whole Brillouin zone. The single MoS2 monolayer is confirmed to be a direct band gap semiconductor. The projected density of states (PDOS) of a single monolayer is calculated and compared to that of bulk MoS2. The effective masses and the orbital character of the band edges at high-symmetry points of the Brillouin zone are determined. The spin-splittings of the conduction band minimum (CBMIN) and valence band maximum (VBMAX) are calculated over the whole Brillouin zone. It is found that the maximum spin-splitting of VBMAX is attained at the K point of the Brillouin zone and is responsible for the experimentally observed splitting between the A1 and B1 excitons.
Keywords: Nanostructures; Electronic band structure; Optical properties; Electronic transport

Temperature coefficients of the refractive index for hydrocarbons and binary mixtures - Wen, Qing; Shen, Jun; Shi, Zheng; Dy, Eben; Michaelian, Kirk H.; Fairbridge, Craig; Astrath, Nelson G. C.; Rohling, Jurandir H.; Baesso, Mauro L. (Chemical Physics Letters, 2012)
Temperature coefficients of the refractive index (dn/dT) for nine hydrocarbons and two sets of binary mixtures were investigated in this work. The measured −dn/dT values for the pure hydrocarbons were found to be inversely proportional to their molar volumes (Vm) and molecular weights (M). Experimental data for binary mixtures show that −dn/dT varies linearly with volume and mass fractions, consistent with theory derived from the linear relationships of −dn/dT with 1/Vm and 1/M for individual hydrocarbons. This study should aid the interpretation of the observed correlations of dn/dT with physical and combustion properties of diesel fuels.

Angle-resolved XPS study of carbon steel passivity and chloride-induced depassivation in simulated concrete pore solution - Ghods, P.; Isgor, O. Burkan; Bensebaa, F.; Kingston, D. (Corrosion Science, 2012)
The passivity and chloride-induced depassivation of carbon steel in simulated concrete pore (CP) solution (pH = 13.3) was investigated using angle-resolved X-ray photoelectron spectroscopy (XPS). After full passivation, the thickness of the oxide film on steel specimens was approximately 5 nm. The oxide films close to the steel substrate were mainly composed of protective Fe(II) oxides while near the free surface the film consisted mostly of Fe(III) oxides. The addition of chloride to the CP solution decreased the thickness of the oxide film and changed its stoichiometry such that near the film/substrate interface the Fe(II)/Fe(III) decreased.
Keywords: Steel reinforced concrete; XPS; Passive films; Passivity

Statistical modelling of the coupled effect of mix design and rebar spacing on restricted flow characteristics of SCC - Ammar, Yahia; Kamal, Khayat H.; Mohammed, Sayed (Construction and Building Materials, 2012)
Self-consolidating concrete (SCC) is designed to exhibit high deformability and stability to maintain homogenous suspension of coarse aggregate particles in the mortar during flow to ensure adequate passing ability of the concrete through restricted areas and the filling of the formwork without any consolidation. Proper deformability and uniform suspension of coarse aggregate particles in the matrix are key parameters to ensure successful casting and adequate in situ performance. The required flow properties of concrete are affected by the rheological properties of the mixture and the characteristics of the cast element, including the level of reinforcement. The mixture proportioning of SCC involves tailoring several mixture parameters to achieve adequate stability and reduce the risk of arching of solid particles and blockage at the vicinity of closely spaced obstacles which is required to ensure proper passing ability and flow characteristics. The objective of this study is to evaluate the coupled effect of mixture parameters and density of reinforcement on flow characteristics of SCC using a statistical design approach. This study seeks to model the coupled effect of the content of supplementary cementitious materials (SCMs), coarse aggregate volume (CA), and density of reinforcement on flowability, passing ability, and filling capacity of SCC. The comparison between predicted and measured responses determined on eight mixtures indicates the accuracy of the established models to describe the effect of the independent variables on the flow behavior of SCC through restricted sections. The derived models show that the flow rate of SCC in the presence of reinforcement is dominated by the content of SCM and clear spacing between the reinforcement. On the other hand, the SCM content is shown to have a three-time greater effect on plastic viscosity than the relative volume of coarse aggregate. Trade-offs between rheological parameters, clear spacing, and flow of SCC in the presence of obstacles showed that for a given clear spacing, higher viscosity and lower yield stress values resulted in higher flow time of concrete. For clear spacing between obstacles of 30 mm, SCC mixtures with plastic viscosity lower than 50 Pa s and yield stress of 45 Pa are shown to ensure proper passing ability.
Keywords: Filling ability; Rheology; Self-consolidating concrete; Statistical design; Restricted flow

Improvement in dynamic properties of laminated MWCNT-polystyrene composite beams via an integrated numerical–experimental approach - Rokni, Hossein; Milani, Abbas S.; Seethaler, Rudolf J.; Stoeffler, Karen (Composite Structures, 2012)
A new concept for the optimization of dynamic behavior of laminated nanocomposites is introduced where fiber orientation factor in continuous fiber-reinforced composites is replaced by different wt.% of carbon nanotubes (CNTs) in each layer. First, at a design concept level, an optimum distribution of multi-walled CNTs (MWCNTs) through the thickness of a typical cantilever beam is sought to achieve its highest fundamental natural frequency for a given weight percent of MWCNTs. This is done using a finite element (FE) model in ABAQUS along with a user-defined Python code. Next, based on the obtained optimum distribution, actual laminated MWCNT/polystyrene (PS) composite beams were fabricated and their effective stiffness, fundamental natural frequencies and damping ratios were measured through static deflection and free vibration tests. It was found that the optimum distribution of MWCNTs resulted in an increase of 21.9% and 10.4% in the effective Young’s modulus and the fundamental damped natural frequency values, respectively, which were almost two-fold higher than those of a beam with a uniform MWCNT distribution. In addition, compared to a pure polymer beam, 38.9% and 27.8% improvements in the damping ratio of the uniformly and optimally distributed MWCNT polymer composite beams were achieved.
Keywords: Structural composites; Carbon nanotubes; Vibration behavior; Testing and modeling

Buckling of conical composite shells - Shadmehri, F.; Hoa, S. V.; Hojjati, M. (Composite Structures, 2012)
A semi-analytical approach is proposed to obtain the linear buckling response of conical composite shells under axial compression load. A first order shear deformation shell theory along with linear strain–displacement relations is assumed. Using the principle of minimum total potential energy, the governing equilibrium equations are found and Ritz method is applied to solve them. Parametric study is performed by finding the effect of cone angle and fiber orientation on the critical buckling load of the conical composite shells.
Keywords: Conical shells; Composite structures; Buckling analysis

Study on laser welding of AA1100-16vol.% B4C metal–matrix composites - Guo, J.; Gougeon, P.; Chen, X.-G. (Composites Part B: Engineering, 2012)
Laser welding of AA1100-16 vol.% B4C metal–matrix composites was explored in the study. It was found that most B4C particles were decomposed and that needle-like AlB2 and Al3BC phases were substantially formed during the welding process without filler. Consequently, a joint efficiency of 63% (UTS) was obtained. The addition of Ti with 150 μm thick foil increased the joint efficiency to 75% due to the decrease of needle-like phase formations. On the other hand, the addition of Ti with filler wire did not show significant tensile property improvement due to the Ti segregation and microstructure inhomogeneity in the weld zone. The fracture surfaces of laser welded joints were investigated to understand the fracture mechanisms.
Keywords: Metal–matrix composites (MMCs); Microstructure; Mechanical properties; Joints/joining; Al–B4C

The development of a conductive carbon nanotube (CNT) network in CNT/polypropylene composite films during biaxial stretching - Shen, Jiabin; Champagne, Michel F.; Yang, Zhi; Yu, Qin; Gendron, Richard; Guo, Shaoyun (Composites Part A: Applied Science and Manufacturing, 2012)
Two developing stages of conducting network in carbon nanotube (CNT)/polypropylene composite films were found during simultaneous biaxial (SIB) stretching and sequential biaxial (SEB) stretching. The electrical resistivity was first increased up to 10¹¹ Ω cm with the extension of the films, regardless of the stretching modes. Once further stretched to 3.5 × 3.5, the SIB- and SEB-stretched films showed reduction of their resistivity of six and eight orders of magnitude, respectively. Microscopic observations revealed that specimens stretching in SEB mode promoted the elongation of CNTs and their clusters, which was apparently more effective for reconnecting adjacent particles and fabricating a new conducting network
Keywords: Polymer–matrix composites (PMCs); Electrical properties

Processing and properties of PEEK/glass fiber laminates: effect of addition of single-walled carbon nanotubes - Ashrafi, Behnam; Díez-Pascual, Ana M.; Johnson, Leon; Genest, Marc; Hind, Simon; Martinez-Rubi, Yadienka; González-Domínguez, Jose M.; Teresa martínez, M.; Simard, Benoit; Gómez-Fatou, Marián A.; Johnston, Andrew (Composites Part A: Applied Science and Manufacturing, 2012)
This work focuses on the effects of the introduction of unwrapped and wrapped single-walled carbon nanotubes (SWCNTs) on the quality (i.e. void content) and a range of different properties of polyether ether ketone (PEEK)/glass fiber (GF) laminates fabricated through hot-compression processing. The quality of the developed multiscale laminates was evaluated by non-destructive inspection techniques (ultrasonic C-scan and thermography), density measurements as well as optical and scanning electron microscopy analyses. The in-plane and transverse thermal and electrical conductivities as well as Short-Beam-Shear (SBS) strength were measured at different locations within each composite panel. It was found that the addition of SWCNT can have a considerable influence on the porosity of manufactured laminates. In summary, while unwrapped SWCNT generally improved the thermal and electrical properties of the PEEK/GF laminates, composites incorporating compatibilizer exhibited the lowest porosity, the highest electrical conductivity and mechanical properties.
Keywords: Nano-structures; Laminates; Physical properties; Thermoplastic resin

Novel wear-resistant materials – Carbon fiber reinforced low-carbon Stellite alloy composites - Khoddamzadeh, A.; Liu, R.; Liang, M.; Yang, Q. (Composites Part A: Applied Science and Manufacturing, 2012)
This paper reports the design and development of a class of new composite materials, which are low-carbon Stellite alloy matrices reinforced with carbon fibers. The focus of the research is to compare the different effects of carbon fibers versus carbides on Stellite alloys. Stellite 25 was selected as the matrix because of its very low carbon content (0.1 wt.%), thus minimal carbide volume fraction. The composite specimens are fabricated using the hot isostatic pressing and sintering techniques. The microstructures of the specimens are examined with optical microscopy in order to identify the possible carbide formation from the carbon fibers. The material characterization of the specimens is achieved through hardness test, sliding wear test and corrosion test. These novel materials exhibit superior properties compared to existing Stellite alloys and are expected to spawn a new generation of materials used for high temperature, severe corrosion, and wear resistant applications in various industries.
Keywords: Metal–matrix composites (MMCs); Carbon fiber; Wear; Corrosion

Poly(phenylene sulphide) and poly(ether ether ketone) composites reinforced with single-walled carbon nanotube buckypaper: II – mechanical properties, electrical and thermal conductivity - Díez-Pascual, Ana M.; Guan, Jingwen; Simard, Benoit; Gómez-Fatou, Marián A. (Composites Part A: Applied Science and Manufacturing, 2012)
The mechanical properties, electrical and thermal conductivity of single-walled carbon nanotube (SWCNT) buckypaper (BP) embedded in poly(ether ether ketone) (PEEK) or poly(phenylene sulphide) (PPS) matrices were investigated. Dynamic mechanical analysis demonstrated a significant increase in the storage modulus and glass transition temperature of the polymers, indicating strong SWCNT–matrix interfacial adhesion. The composites showed improved stiffness and strength, as revealed by tensile and flexural tests, while their ductility and toughness moderately decreased. Exceptional enhancements in the electrical and thermal conductivity of PPS and PEEK were found. Their Young’s moduli and thermal conductivities were compared with the predictions of theoretical models. This investigation indicates that SWCNT-BPs possess great potential to improve the performance of thermoplastics and satisfy a wide variety of demands in multi-disciplinary technological applications.
Keywords: Polymer–matrix composites (PMCs); Carbon nanotube buckypaper; Electrical properties; Mechanical testing

Poly(phenylene sulphide) and poly(ether ether ketone) composites reinforced with single-walled carbon nanotube buckypaper: I – structure, thermal stability and crystallization behaviour - Díez-pascual, Ana M.; Guan, Jingwen; Simard, Benoit; Gómez-fatou, Marián A. (Composites Part A: Applied Science and Manufacturing, 2012)
Single-walled carbon nanotube (SWCNT) buckypaper (BP) reinforced-poly(phenylene sulphide) (PPS) and poly(ether ether ketone) (PEEK) composite laminates were manufactured through hot-press processing. Scanning and transmission electron microscopies were used for morphological characterization and qualitative evaluation of the impregnation degree of the BP. The thermal stability, resin and void content of the composites were evaluated through thermogravimetric analysis; a strong increase in the degradation temperatures of the polymers was found. Raman spectra revealed the existence of strong filler–matrix interactions. The glass transition temperature, crystallization and melting behaviour of the composites were investigated through differential scanning calorimetry and their crystalline structure was analyzed by wide angle X-ray diffraction. This investigation confirms that SWCNT-BPs can be used to fabricate high-loading CNT/thermoplastic composites with improved thermal properties.
Keywords: Thermoplastic resin; Carbon nanotube buckypaper; Thermal properties; Electron microscopy

A fuzzy matchmaking approach for Semantic Web Services with application to collaborative material selection - Liu, Min; Shen, Weiming; Hao, Qi; Yan, Junwei; Bai, Li (Computers in Industry, 2012)
A critical step in the process of reusing existing WSDL-specified services for building web-based applications is the discovery of potentially relevant services. However, the category-based service discovery, such as UDDI, is clearly insufficient. Semantic Web Services, augmenting Web service descriptions using Semantic Web technology, were introduced to facilitate the publication, discovery, and execution of Web services at the semantic level. Semantic matchmaker enhances the capability of UDDI service registries in the Semantic Web Services architecture and it is able to recognize various degrees of matching for Web services. Based on the Semantic Web Service framework, semantic matchmaker, specification matching and probabilistic matching, this paper proposes a fuzzy matchmaking approach for Semantic Web Services to support a more automated and veracious service discovery process in collaborative manufacturing environments. In the proposed approach, the membership function is set up on the semantic information annotated on WSDL specification of a web service, and the similarity of service objects is evaluated by the similarity degree of service attributes. A collaborative material selection case study in the die casting process for thermoelectric fan housing is used to illustrate the proposed approach.
Keywords: Semantic Web Services; Similarity; Matchmaking; Fuzzy-set; Material selection

A comprehensive analysis of the morphology of first-year sea ice ridges - Strub-Klein, Lucie; Sudom, Denise (Cold Regions Science and Technology, 2012)
A review of the morphological properties of over 300 full-scale floating first-year sea ice ridges has been made, including measurements from 1971 until the present time. Ridges were examined from the Bering and Chukchi Seas, Beaufort Sea, Svalbard waters, Barents Sea and Russian Arctic Ocean for the Arctic regions; and from the Canadian East Coast, Baltic Sea, Sea of Azov, Caspian Sea and Offshore Sakhalin for the Subarctic (or temperate) regions. Grounded ridges were excluded. A wide catalogue comprising the ridge thicknesses (sail, keel and consolidated layer), widths and angles as well as the macroporosity and the block dimensions is provided. The maximum sail height was found to be 8 m (offshore Sakhalin), and the mean peak sail height was 2.0 m, based on 356 profiles. The mean peak keel depth is 8.0 m, based on 321 profiles. The relationship between the maximum sail height, hs, and the maximum keel depth, hk, for all ridges is best described by the power equation hk = 5.11hs0.69. The correlation differs depending on the region. For Arctic ridges a linear relationship was found to be the best fit (hk = 3.84hs), while for the Subarctic ridges a power relationship (hk = 6.14hs0.53) best fit the data. The ratio of maximum keel to maximum sail is 5.17 on average (based on 308 values), and has also been calculated for each region mentioned above. Arctic ridges generally have a lower keel-to-sail ratio than those in Subarctic regions. The statistical distribution of keel-to-sail ratios is best represented by a gamma distribution. The average sail and keel widths were 12 and 36 m, respectively. The relationships between the sail and keel widths and other geometrical parameters were also determined. Variation of sail and keel thicknesses within individual ridges has been compared with the variability of all ridges. Ridge cross-sectional geometry can vary greatly along the length of a ridge, even over a short distance. A study was made on sail block thicknesses, and it was found that they correlate well with the sail height with a square root model. The typical macroporosity for a first-year ice ridge is 22% (based on 58 values) with an average sail macroporosity of 18% (based on 49 values) and average keel rubble macroporosity of 20% (based on 44 values). The average ridge consolidated layer thickness was 1.36 m based on 118 values. The variation of the consolidated layer was examined, and it was found that the layer tends to grow evenly with time over the width of the ridge cross section. A greater spacing between the measurements seemed to affect the variation, as it decreased with an increasing distance between each borehole. A statistical analysis based on 377 measurements of the consolidated layer of ridges in the Barents Sea showed that the gamma distribution well describes the distribution of the consolidated layer thicknesses in that area.
Keywords: First-year ridges; Ratios; Block dimensions; Macroporosity; Consolidated layer

On borehole indentor (BHI) measurements and analysis - Sinha, Nirmal K.; Shkhinek, Karl; Smirnov, Victor (Cold Regions Science and Technology, 2012)
In situ measurements on stress–indentation curves conducted with the National Research Council (NRC), Canada and the Arctic and Antarctic Research Institute (ARRI), Russia borehole indentors (BHI) are analyzed and classified. This establishes harmony with laboratory observations on stress–strain diagrams and some compatibility with the recommendations (ISO/DIS 19906) on estimating uniaxial ice strengths from BHI strengths. The analysis is devoted mainly to consider the influence of local ice conditions and the indentation rates on the pressure–indentation curves. Simultaneous records of the acoustic emission (AE) detected by accelerometers installed on the ice surface, within 1.5 m of the indentation plate, indicated that major cracks are nucleated at the ice/plate interface. Microstructural analysis of the indented ice confirmed this important conclusion in addition to revealing recrystallization as well as healing activities in the indented ice. An attempt, with extremely limited success, has been made in applying conventional ice failure criteria for predicting the observed stress–indentation curves. Phenomenologically, however, a power-law between the indentation-rate and upper-yield strength exhibits the same rate sensitivity (about 3) usually obtained for strain-rate dependence of uniaxial strengths. Numerical solutions of the rate-sensitive indentation processes must be developed (as has successfully been achieved for uniaxial tests) on microstructure-property based mathematical (rheological) model that includes the effects of the rate-dependent kinetics of deformation, microcracking and crack-enhanced creep. Premature brittle fractures are contact problems and modeling must consider the nucleation of cracks in ice at the ice/plate contact surface.
Keywords: Ice strength; In-situ; Borehole indentor; Failure classification; Acoustic-emissions; Microstructural analysis

Advanced MR imaging techniques and characterization of residual anatomy - Stroman, P. W.; Bosma, R. L.; Kornelsen, J.; Lawrence-Dewar, J.; Wheeler-Kingshott, C.; Cadotte, D.; Fehlings, M. G. (Clinical Neurology and Neurosurgery, 2012)
Advances in technology in recent decades have contributed to rapid developments in non-invasive methods for imaging human anatomy, and advanced imaging methods are now one of the primary tools for clinical diagnosis after neurological trauma or disease. Here we review the current and upcoming capabilities of one of the most rapidly developing methods, magnetic resonance imaging (MRI). The underlying theory is introduced so that the reasons for the strengths, weaknesses, and future expectations of this method, can be explained. Current techniques for imaging anatomical changes, inflammation, and changes in white matter, axonal integrity, blood flow and function, are reviewed. Applications for specific purposes of assessing traumatic injury in the brain or spinal cord, and for multiple-sclerosis are also presented, and are used as examples of how the advanced techniques are being used in practice.
Keywords: Magnetic resonance imaging (MRI); Clinical applications; Functional MRI; Diffusion tensor imaging; Perfusion; Relaxation times; Multiple sclerosis; Traumatic brain injury

Application of a new procedure for the optimization of variable thickness drawing of aluminium tubes - Bihamta, R.; Bui, Q. H.; Guillot, M.; D’Amours, G.; Rahem, A.; Fafard, M. (CIRP Journal of Manufacturing Science and Technology, 2012)
The application of aluminium tubes, especially with variation of thickness, in the structures of various transportation devices like cars and bicycles makes it a point of interest for various designers. In this paper, the variable thickness tube drawing process was studied with a newly developed procedure to evaluate the effect of tools geometries on the maximum possible tube deformation. The procedure applies the desired variation in the design variables (die angle, mandrel angle, and die fillet radius) and the required adjustments and changes in the geometries with the aid of an in-house code automatically. Based on the optimized results, a die and a mandrel were built to verify numerical results in variable thickness tube drawing. The numerical results were compared with the experiments in the prototype machine, which was designed by this group, and acceptable agreements were observed.
Keywords: Optimization; Finite element method; Metal forming; Tool design; Tube drawing; AA6063

Upward- or downward-breaking cones in ice : which one should you use? - Barker, A.; Sayed, M. (Cold Regions Engineering 2012 : Sustainable Infrastructure Development in a Changing Cold Environment, 2012)
As an ice sheet impinges on the surface of a cone, flexural (or bending) failure is likely to take place. That ice failure mode causes substantially lower forces than the case of compressive failure, which would take place if ice is to encounter a vertical structure. Some designs further adopt inverted cones, as downward-breaking of ice may produce lower forces. The present study employs a numerical model of ice dynamics in order to predict ice failure patterns, ice clearing around the structure, and forces on the structure. Performance of the model is validated against tests done in the Esso Resources Canada Ltd. ice basin during 1989 and 1990. The paper then proceeds to examine a test case representing a pier of the Confederation Bridge. The results are compared to available observations. Simulations also examine the role of the slope of the cone and the case of ice failure against inverted cones. Comparison of downward-breaking and upward-breaking indicate that the slope plays a role. For a relatively steep slope of 52°, the downward-breaking cone experiences a substantially lower force than the upward-breaking cone. For a gentler 40° slope, the downward- and upward-breaking cones experienced similar values of peak ice forces. The results have applications for bridge pier and offshore wind turbine tower designs, offshore oil and gas exploration and production structures, and standards development, such as the ISO 19906 Arctic Offshore Structures standard, which also has applications for temperate regions.
Keywords: Ice; Conical structures; Numerical simulations; Confederation Bridge; downward ice breaking

Characterization and optimization of orbital drilling of woven carbon fiber reinforced epoxy laminates - Sadek, A.; Meshreki, M.; Attia, M. H. (CIRP Annals - Manufacturing Technology, 2012)
The emerging process of orbital drilling (OD) can greatly reduce or eliminate the defects associated with the drilling of composites; e.g., delamination, and thermal damage. The effects of the OD process parameters on the hole quality attributes were established in the form of machinability maps; an aspect that has not been reported before. The results showed significant enhancement in the hole quality compared to conventional drilling, due to the reduced axial force and cutting temperature, resulting from the redistribution of the load exerted by cutting edges and the cooling effect of the unstable rotational air flow in the tool-workpiece annular gap.
Keywords: Drilling; Composite; Defect

Polarity-adjustable reversed phase ultrathin-layer chromatography - Hall, J. Z.; Taschuk, M. T.; Brett, M. J. (Journal of Chromatography A, 2012)
Reversed phase thin layer chromatography (TLC) or high performance thin layer chromatography (HPTLC) plates modified with C18, C8 or C2 to provide the silica-gel stationary phase with different polarities are available on the market, however, reversed phase plates with tunable polarity have not been reported. Given the limited variety of reversed phase plates, mobile phase composition optimization is necessary to obtain better separation of analytes with similar characteristics, which is often a time consuming step. We present polarity-adjustable reversed phase ultrathin-layer chromatography (UTLC) plates, which simplifies the mobile phase screening process and greatly expands the selection of reversed phase plates. The plates were fabricated on glass substrates with SiO2 nanopillars deposited using the glancing angle deposition (GLAD) technique. SiO2 nanopillars were functionalized with octadecyltrichlorosilane to generate a super hydrophobic stationary phase. Unlike commercial silica-gel based stationary phases, the isolated nanopillar architecture presented here exposes a high surface area to post-fabrication surface treatments. In our work, an O2 plasma treatment at different powers, pressures and exposure times was used to shorten the silane carbon chain and introduce COOH groups to the surface, producing plates with finely tunable polarities. Separation of a model dye mixture of Sudan blue and Sudan IV confirmed the tuning of surface polarities by measurement of retention behavior changes. The dye elution order reversed as a result of the change in surface polarity. When the same plasma treatment process was tested on commercial reversed phase plates, separation behavior did not change because the disordered and tortuous silica gel restricts the accessible surface area. Plasma treatment of GLAD structures with highly accessible surfaces improved control over interfacial properties, producing better reverse phase separations.
Keywords: Glancing angle deposition; UTLC; Reversed phase

Analysis of pseudomonas quinolone signal and other bacterial signalling molecules using capillaries coated with highly charged polyelectrolyte monolayers and boron doped diamond electrode - Zhou, Lin; Reen, F. Jerry; O’Gara, Fergal; McSweeney, Christina M.; Clarke, Sarah L.; Glennon, Jeremy D.; Luong, John H. T.; McGlacken, Gerard P. (Journal of Chromatography A, 2012)
Coated capillary electrophoresis equipped with a boron doped diamond (BDD) electrode was developed for analysis of chemically synthesised 2-heptyl-3-hydroxy-4-quinolone (HHQ), 2-heptyl-3-hydroxy-4-quinolone (PQS), and 2-methyl analogues. Detection was then extended to biological samples. PQS and its biological precursor, HHQ, are two key regulators of bacterial cooperative behaviour known as quorum sensing in the nosocomial pathogen Pseudomonas aeruginosa. The fused silica capillary was coated with a thin layer of poly (diallyldimethylammonium) chloride to reverse the electroosmosis, allowing fast migration of PQS and HHQ with improved selectivity. The four model compounds were baseline resolved using a 50 mM H3PO4–Tris, pH 2.0 buffer with 20% (v/v) acetonitrile as buffer additive. With an injection time of 3 s, the detection limits of four analytes ranging from 60 to 100 nM (S/N = 3) were observed when the BDD electrode was poised at +1.5 V vs. 3 M Ag/AgCl. As expected, no PQS or HHQ was detected from the supernatant of the P. aeruginosa (pqsA) mutant. A concentration of HHQ of 247 μM was detected from the supernatant of the pqsH mutant, which catalyses the conversion of HHQ to PQS in the presence of molecular oxygen by monooxygenase. The separation and detection scheme was applicable to follow the conversion of HHQ to PQS in P. aeruginosa when entering the stationary phase of growth. The results obtained by coated capillary electrophoresis with BDD detection were validated and compared well with LC–MS data.
Keywords: Capillary electrophoresis; PQS; HHQ; Biomarker detection

Time resolved chromatograms in ultra-thin layer chromatography - Oko, A. J.; Jim, S. R.; Taschuk, M. T.; Brett, M. J. (Journal of Chromatography A, 2012)
Ultrathin-layer chromatography (UTLC) is a recently developed analytical method intended for compact, rapid separations of nanolitre analyte volumes. Optimizing this method's performance requires new measurement techniques compatible with the millimetre length scales and rapid separation dynamics observed in UTLC. We have designed, implemented and characterized a measurement system which records UTLC separations in full color with 32 μm spatial resolution and 33 ms temporal resolution. Our code analyzes multiple tracks per plate, filters analyte spots by color, and automatically generates time-resolved figures of merit. The instrument presented here captures a wealth of information from a UTLC separation, and should provide insight into UTLC physics and improved analytical performance.
Keywords: Planar chromatography; Ultrathin-layer chromatography; Time resolved thin layer chromatography; Real-time analysis; Automated color-filtered chromatograms

Tunable thick polymer coatings for on-chip electrophoretic protein and peptide separation - He, Mei; Zeng, Yong; Jemere, Abebaw B.; Harrison, D. Jed (Journal of Chromatography A, 2012)
We report a variety of procedures for fabricating confinement-induced polymer coatings, used to eliminate non-specific protein adsorption and to control electroosmotic flow for microchip capillary electrophoresis. The coating strategy generates relatively thick polymer wall coatings (100–700 nm) and can easily be tuned by adjusting the monomer concentration. 2-hydroxyethyl methacrylate (HEMA) polymer coating, photopatterned in microfluidic channels, effectively reduced protein non-specific adsorption and rendered high efficiency (N/m = ∼3 × 10^6) for protein separation. The coating strategy provides rapid and effective means to create robust wall coatings, with the ability to photograft various surface chemistries onto the coating. [2-(methacryloyloxy) ethyl] trimethylammonium chloride grafted HEMA coated channels showed high durability and reproducibility for generating EOF (RSD = 2.6%, n = 64) over a period of 15 days. Sulfobetaine methacrylate grafted HEMA coated channels allowed separation of BSA digest, 15 peaks resolved in 25 s, with an average N/m of 4 × 10^5.
Keywords: Microfluidics; Thick polymer coating; Capillary electrophoresis; Open-tubular electrochromatography

Proton exchange in acid–base complexes induced by reaction coordinates with heavy atom motions - Alavi, Saman; Taghikhani, Mahdi (Chemical Physics, 2012)
We extend previous work on nitric acid–ammonia and nitric acid–alkylamine complexes to illustrate that proton exchange reaction coordinates involve the rocking motion of the base moiety in many double hydrogen-bonded gas phase strong acid–strong base complexes. The complexes studied involve the biologically and atmospherically relevant glycine, formic, acetic, propionic, and sulfuric acids with ammonia/alkylamine bases. In these complexes, the magnitude of the imaginary frequencies associated with the proton exchange transition states are <400 cm−1. This contrasts with widely studied proton exchange reactions between symmetric carboxylic acid dimers or asymmetric DNA base pair and their analogs where the reaction coordinate is localized in proton motions and the magnitude of the imaginary frequencies for the transition states are >1100 cm−1. Calculations on complexes of these acids with water are performed for comparison. Variations of normal vibration modes along the reaction coordinate in the complexes are described.
Keywords: Proton exchange reactions; Acid–base complexes; Atmospheric acid–base complexes; Acid–water complexes; Electronic structure calculations

The dissolution mechanism of sulphur in hydrous silicate melts. I: Assessment of analytical techniques in determining the sulphur speciation in iron-free to iron-poor glasses - Klimm, Kevin; Kohn, Simon C.; O'Dell, Luke A.; Botcharnikov, Roman E.; Smith, Mark E. (Chemical Geology, 2012)
S K-edge XANES, λ (SKα) wavelength shift, 33S MAS NMR and Raman spectroscopy have been applied to a series of experimentally synthesised hydrous sulphur bearing silicate glasses to determine the oxidation state of sulphur dissolved in the glass. Glasses investigated include soda–lime glass (SLG), K2Si4O9 (KSG) and albitic (Albite) and trondhjemitic (TROND) glass compositions. The four spectroscopic techniques are compared with each other to investigate the applicability of each technique as a method to determine the sulphur oxidation state and structural aspects of sulphur dissolution in silicate melts. XANES and Raman spectroscopy provide the most comprehensive information on the S-speciation and S6 + and S2 − (plus S4 + in the case of XANES) can be detected. XANES allows detection of S-species at lower concentrations (< 50 ppm) than all the other methods. NMR also allows direct determination of S6 + and S2 − in the glasses. However, signal loss in NMR prevents both S6 + and S2 − to be detected simultaneously even in samples where the presence of both species can be confirmed using XANES and Raman. Measuring the λ (SKα) wavelength shift does not provide direct constraints on the S-species in silicate glasses but can be used to determine the S6 +/ΣS when corrected for beam damage. λ (SKα) wavelength shift determination works best for S and Fe-rich glasses because in Fe-free hydrous glasses and at low S contents significant beam damage is observed, requiring an intensive correction procedure to account for changes of S6 +/ΣS during electron beam exposure. The other techniques show either no (NMR and Raman) or minimal (XANES) beam damage that can be easily avoided by moving the sample during spectra acquisition. The linear combination of XANES spectra of glasses containing either only S2 − or S6 + provides direct constraints on the S6 +/ΣS of glasses containing a mixture of S2 − and S6 +. In addition the Raman intensities of bands related to S6 + and S2 − can also be used to quantify S6 +/ΣS and determined values are in good agreement with those obtained by XANES at least for S contents of > 150 ppm. XANES and Raman both show that the dissolution of S2 − is different in Fe-free and Fe-bearing hydrous glasses. In Fe-free glasses S2 − is present as SH− and H2S whereas Fe–S complexes are observed in the presence of Fe.
Keywords: S K-edge XANES; λ (SKα) wavelength shift; 33S MAS NMR; Raman spectroscopy; Sulphur oxidation state; Silicate glass

Enhanced rate of gas hydrate formation in a fixed bed column filled with sand compared to a stirred vessel - Linga, Praveen; Daraboina, Nagu; Ripmeester, John A.; Englezos, Peter (Chemical Engineering Science, 2012)
The performance of two gas/liquid contact modes was evaluated in relation to the rate of gas hydrate formation. Hydrate formation experiments were conducted for several gas mixtures relevant to natural gas hydrate formation in the earth (CH4, CH4/C3H8, CH4/C2H6 and CH4/C2H6/C3H8) and two CO2 capture and storage (CO2, CO2/H2/C3H8). One set of experiments was conducted in a bed of silica sand, saturated with water (fixed fed column) while the other experiment was conducted in a stirred vessel for each gas/gas mixture. Both sets of experiments were conducted at a constant temperature. The rate of hydrate formation is customarily correlated with the rate of gas consumption. The results show that the rate of hydrate formation in the fixed bed column is significantly greater and thereby resulted in a higher percent of water conversion to hydrate in lesser reaction time for all the systems studied.
Keywords: Carbon dioxide; Natural gas; Gas hydrates; Enhanced kinetics; Porous media; Mass transfer

Probabilistic modeling of chloride-induced corrosion in concrete structures using first- and second-order reliability methods - Saassouh, Bassem; Lounis, Zoubir (Cement and Concrete Composites, 2012)
Concrete structures are subjected to chloride-induced corrosion that can lead to shortened service life. Reliable predictions of life cycle performance of concrete structures are critical to the optimization of their life cycle design and maintenance to minimize their life cycle costs. This paper presents two simplified semi-analytical probabilistic models based on the first- and second-order reliability methods to model the uncertainty of the key parameters including surface chloride concentration, chloride threshold, cover depth and diffusion coefficient, which govern the chloride ingress into concrete and corrosion of reinforcing steel. A case study of a reinforced concrete highway bridge deck is used to illustrate the capability and efficiency of these simplified probabilistic models in modeling the uncertainty and predicting the time-dependent probability of corrosion. The models enable to quantify the impact of the different governing parameters on probability of corrosion and service life, which can be used to develop cost-effective management strategies.
Keywords: Chloride ingress; Corrosion initiation; Uncertainty modeling; First- and second-order reliability methods; Importance factor; Probability of corrosion

Fine limestone additions to regulate setting in high volume fly ash mixtures - Bentz, Dale P.; Sato, Taijiro; de la Varga, Igor; Weiss, W. Jason (Cement and Concrete Composites, 2012)
High volume fly ash (HVFA) concrete mixtures are being considered more frequently due to their cost and sustainability advantages. While the long term performance of these HVFA concretes typically meets or exceeds that of conventional concretes, their early age performance is often characterized by excessive retardation of the hydration reactions, delayed setting times, and low strengths. Extending an HVFA mixture to a ternary blend that incorporates a fine limestone powder may provide a viable solution to these deficiencies, particularly the hydration retardation and setting issues. In this paper, a nano-limestone powder and two other limestone fillers of increasing median particle size (4.4 μm and 16.4 μm) are investigated for their propensity to accelerate early age reactions and reduce setting times in a Class C fly ash/cement blend. The fineness of the limestone has measurable effects on its efficacy in accelerating hydration and decreasing setting times. Companion specimens prepared with a fine silica powder suggest that the fine limestone may act favorably through both a physical and a chemical mechanism. Isothermal calorimetry and Vicat needle penetration measurements on pastes are accompanied by strength measurements on mortars, to verify that the limestone powder substitutions are not negatively impacting strength development. A linear relationship with a reasonable correlation is found to exist between 1 d and 7 d compressive strengths of mortars and their accompanying cumulative heat release values as determined using isothermal calorimetry.
Keywords: Blended cement; High volume fly ash; Isothermal calorimetry; Limestone; Particle size; Setting; Strength; Ternary blend

Flocculation of bacteria by depletion interactions due to rod-shaped cellulose nanocrystals - Sun, Xiaohui; Danumah, Christophe; Liu, Yang; Boluk, Yaman (Chemical Engineering Journal, 2012)
We report depletion induced flocculation and phase separation of bacteria due to the presence of rod-shaped nanoparticles by using confocal laser microscopy and turbidity measurements. To investigate the depletion effect of rod shaped nanoparticles in bacteria systems, cellulose nanocrystals with length, L = 90 ± 10 nm, diameter, D = 8 ± 1 nm and zeta potential of 51.5 ± 0.8 mV was used. The flocculation of the Gram-negative bacterium Pseudomanas aeruginosa (average length = 1.2 μm, width = 0.2 μm) was tested. The zeta potential of P. aeruginosa suspended in 10 mM NaCl was −29.84 ± 0.6 mV. Bacterial flocculation was observed at the CNC concentration of less than 0.1% due to the depletion effect. We conclude from our results that rod shaped nanoparticles are very effective for the depletion flocculation of colloidal size bacteria and that phase separation of bacteria can occur at very low concentrations of rodlike CNC particles.
Keywords: Flocculation; Bacteria; Depletion; Cellulose nanocrystals

Highly active Pt–Ru nanowire network catalysts for the methanol oxidation reaction - Li, Bing; Higgins, Drew C.; Zhu, Shaomin; Li, Hui; Wang, Haijiang; Ma, Jianxin; Chen, Zhongwei (Catalysis Communications, 2012)
Platinum–ruthenium alloy nanowire networks (Pt–Ru NWNs) have been successfully synthesized by a surfactant assisted soft template strategy, involving the chemical reduction of platinum and ruthenium complexes using sodium borohydride. These materials are investigated as methanol oxidation reaction (MOR) catalysts for fuel cell applications and were found to display exemplary MOR activity and CO tolerance through cyclic voltammetry (CV) testing. Pt–Ru-NWNs investigated in this work are proposed as promising anode replacements to traditional Pt–Ru catalysts in direct methanol fuel cells.
Keywords: DMFC; Nanowire networks; Pt–Ru; Methanol oxidation reaction; Electrocatalyst

The structural diversity of lipopolysaccharide expressed by non-typeable Haemophilus influenzae strains 1158 and 1159 - Vitiazeva, Varvara; Li, Jianjun; Hood, Derek W.; Moxon, E. Richard; Schweda, Elke K. H. (Carbohydrate Research, 2012)
A heterogeneous population of glycoforms expressed by NTHi strains 1158 and 1159 has been elucidated using NMR spectroscopy and capillary electrophoresis coupled to electrospray ionization mass spectrometry (CE-ESI-MS) on O-deacylated LPS (LPS-OH) and core oligosaccharide (OS) materials, as well as HPLC-ESI-MSn on dephosphorylated and methylated OS samples. The most abundant glycoform contained a disaccharide chain: PCho→7)-D-α-D-Hepp-(1→6)-β-D-Glcp linked to HepI from the common structural element of H. influenzae LPS: L-α-D-HepIIIp-(1→2)-[PEtn→6]-L-α-D-HepIIp-(1→3)-L-α-D-HepIp-(1→5)-[PPEtn→4]-α-Kdop-(2→6)-lipid A. Phosphocholine (PCho) was found at two positions in the LPS glycoforms; PCho substituted the 6-position of β-D-Glcp attached to HepIII and was also located at a novel position linked to D-α-D-Hepp; this latter position was determined by structural analysis of LPS from a 1158lpsA mutant strain. Additionally, HPLC-ESI-MSn experiments indicated glycoforms that have chain elongation from HepII, this was found only in glycoforms, which lack the additional heptose in the outer core region. Structural details of these glycoforms were confirmed by analyses of LPS from a 1158losB2 mutant strain; the losB2 gene is required for addition of the d,d-Hep to the outer core region in strain 1158.
Keywords: Haemophilus influenzae, Lipopolysaccharide, Globotetraose, Sialyllactose, Phosphocholine

Plausible transition states for glycosylation reactions - Whitfield, Dennis M. (Carbohydrate Research, 2012)
The Transition State (TS) for any chemical glycosylation reaction is not known with certainty. Both experimental and computational approaches have been limited due to the complexity of the problem. This work describes a preliminary computational ionization approach using density functional theory calculations to arrive at hypothetical TSs. The new TSs contain the glycosyl donor as anomeric triflates, the acceptor as methanol, some CH2Cl2 molecules, and a Li+ ion promoter. In this computational approach all glycosylations are disassociative in that the C-1–OTf bond length is greater then 2 Å before any nucleophilic attack. All nucleophilic attack requires some preassociation of the nucleophile with examples of the pre-attack complexation to donor oxygens. These hypothetical models are intended to guide both experimental and computational approaches to finding TSs for glycosylation reactions that can be used to optimize stereoselectivity of glycosylation.
Keywords: Glycosylation; Transition states; Density functional theory; Oxacarbenium ion

Evaluation of the regioselective delactonization of tri-sialic acid lactone by in-solution molecular dynamics simulation - Chen, Chien-Sheng; Yu, Yi-Ping; Hsu, Chun-Hua; Zou, Wei; Fang, Jim-Min; Wu, Shih-Hsiung (Carbohydrate Research, 2012)
An approximate model for the delactonization of tri-sialic acid lactone is presented with two water-layers that led to neutral hydrolysis of δ-lactone. The hydrolytic reactivity was studied with a 10-ns in-solution molecular dynamics simulation. The initial step of this hydrolysis involves a reactant water nucleophile complex via a proton transfer with another water molecule. Therefore, the probability of water molecules localized at the hydrolytic center correlates to the hydrolysis of δ-lactone. The stepwise delactonization of α2,8-(NeuAc)3 lactone results/resulted from water concentration discrepancy near the carbonyl carbon of lactones in two water oxygen⋯carbonyl carbon shells, and the distances of Odouble bondC⋯Owater layers were 2.8 Å and 5.1 Å. Based on in-solution molecular dynamics study, the motion of water molecules over the re-face of the carbonyl groups was used for the quantitative description of the residence probability, p, whose value is 0.11 for lactone I and 0.33 for lactone II. The geometric criteria used to determine the residence statistics are (1) the distance of water–oxygen⋯carbonyl carbon in less than 5.1 Å and (2) the cone angle, θ, of carbonyl Odouble bondC⋯Owater in the range of 85–115°. As expected, a higher residence probability at lactone II led to its faster hydrolysis. Both the radial g(r) and angular p(θ) pair distribution functions of water oxygen and carbonyl groups of lactones ensure a better surrounding hydration encounter for lactone II. In contrast, water molecules around lactone I are deduced due to a steric hindrance by the turn structure of α2,8-(NeuAc)3 lactone.
Keywords: Sialic acid; Lactone; Regioselectivity; Reactant complex; Molecular dynamics

Structural characterization of surface glycans from Clostridium difficile - Reid, Christopher W.; Vinogradov, Evgeny; Li, Jianjun; Jarrell, Harold C.; Logan, Susan M.; Brisson, Jean-Robert (Carbohydrate Research, 2012)
Whole-cell high-resolution magic angle spinning (HR-MAS) NMR was employed to survey the surface polysaccharides of a group of clinical and environmental isolates of Clostridium difficile. Results indicated that a highly conserved surface polysaccharide profile among all strains studied. Multiple additional peaks in the anomeric region were also observed which prompted further investigation. Structural characterization of the isolated surface polysaccharides from two strains confirmed the presence of the conserved water soluble polysaccharide originally described by Ganeshapillai et al. which was composed of a hexaglycosyl phosphate repeat consisting of [→6)-β-D-Glcp-(1-3)-β-D-GalpNAc-(1-4)-α-D-Glcp-(1-4)-[β-D-Glcp(1-3]-β-D-GalpNAc-(1-3)-α-D-Manp-(1-P→]. In addition, analysis of phenol soluble polysaccharides revealed a similarly conserved lipoteichoic acid (LTA) which could be detected on whole cells by HR-MAS NMR. Conventional NMR and mass spectrometry analysis indicated that the structure of this LTA consisted of the repeat unit [→6)-α-D-GlcpNAc-(1-3)-[→P-6]-α-D-GlcpNAc-(1-2)-D-GroA] where GroA is glyceric acid. The repeating units were linked by a phosphodiester bridge between C-6 of the two GlcNAc residues (6-P-6). A minor component consisted of GlcpN-(1-3) instead of GlcpNAc-(1-3) in the repeat unit. Through a 6–6 phosphodiester bridge this polymer was linked to →6)-β-D-Glcp-(1-6)-β-D-Glcp-(1-6)-β-D-Glcp-(1-1)-Gro, with glycerol (Gro) substituted by fatty acids. This is the first report of the utility of HR-MAS NMR in the examination of surface carbohydrates of Gram positive bacteria and identification of a novel LTA structure from Clostridium difficile.
Keywords: Clostridium difficile; Lipocarbohydrate; Lipoteichoic acid; Capsular polysaccharide; High-resolution magic angle spinning (HR-MAS) NMR

Identification of the methyl phosphate substituent at the non-reducing terminal mannose residue of the O-specific polysaccharides of Klebsiella pneumoniae O3, Hafnia alvei PCM 1223 and Escherichia coli O9/O9a LPS - Kubler-Kielb, Joanna; Whitfield, Chris; Katzenellenbogen, Ewa; Vinogradov, Evgeny (Carbohydrate Research, 2012)
O-specific polysaccharides of Gram-negative bacteria are synthesized by two different mechanisms: polymerization of the pre-formed O-repeating unit or sequential addition of the monosaccharides to the growing polysaccharide chain. In the second case, growth of the polymer can be further subdivided into two groups depending on the presence or absence of a special monosaccharide or non-sugar substituent that terminates the glycan. A family of polymannose O-polysaccharides provides prototypes for the chain terminating process. Polysaccharides of Klebsiella pneumoniae O3, Hafnia alvei PCM 1223, and Escherichia coli O9 have the same penta-mannose repeating unit. E. coli O9a has tetra-mannose repeat and this structure can be produced by mutants of E. coli O9. The mechanism of biosynthesis of H. alvei 1223 O-polysaccharide has not been reported. Here we show that all above polysaccharides contain the same modification at the non-reducing end; presence of a methyl phosphate group at O-3 of α-mannopyranose, that serves as the signal for termination of the chain elongation.
Keywords: Hafnia; Klebsiella; LPS; Methyl phosphate; O-specific polysaccharide

Thermal and electrical conductivity of array-spun multi-walled carbon nanotube yarns - Jakubinek, Michael B.; Johnson, Michel B.; White, Mary Anne; Jayasinghe, Chaminda; Li, Ge; Cho, Wondong; Schulz, Mark J.; Shanov, Vesselin (Carbon, 2012)
The electrical resistivity of CNT yarns of diameters 10–34 μm, spun from multi-walled carbon nanotube arrays, have been determined from 2 to 300 K in magnetic fields up to 9 T. The magnetoresistance is large and negative at low temperatures. The thermal conductivity also has been determined, by parallel thermal conductance, from 5 to 300 K. The room-temperature thermal conductivity of the 10 μm yarn is (60 ± 20) W m−¹ K−¹, the highest measured result for a CNT yarn to date. The thermal and electrical conductivities both decrease with increasing yarn diameter, which is attributed to structural differences that vary with the yarn diameter.

Zero peak housing: exploring the possibility of eliminating electrical draws from houses during periods of high demand on the electrical grid - Pietila, Andrea; Beausoleil-Morrison, Ian; Newsham, Guy R. (Building and Environment, 2012)
Residential buildings constitute one of the largest demands for electricity. Although the contribution of air-conditioning to total energy use is quite small in many climates, this end-use can place a disproportionate demand upon the central electrical generation, transmission, and distribution system, particularly in the late afternoon of hot summer days. Even in some heating dominated climates, these can be the times of system-wide peak demand, and it is common for electrical systems (such as in Ontario, Canada) to meet marginal demands during these peak periods using generators fired by GHG-intensive fuels (coal and natural gas). The viability of achieving a zero peak house (ZPH)—a house that draws no electricity from the grid during system-wide peak periods—has been assessed via detailed building performance simulations using a case study house based upon a tract-built design in Toronto, Ontario, Canada. It was found that 41%–51% of the goal of eliminating electricity consumption during the summer Ontario on-peak period (11h00 to 17h00 during weekdays from May 1 through October 31) could be achieved through a combination of architectural, control, efficiency, and occupant behaviour measures. It was also found that the remaining demand for electricity could be completely eliminated using realistically sized photovoltaic and battery systems for on-site generation and storage of electricity.
Keywords: Zero peak housing; Electric loads; Housing; Air-conditioning (cooling)

Development and application of a protocol to evaluate impact of duct cleaning on IAQ of office buildings - Zuraimi, M. S.; Magee, Robert; Nilsson, Gregory (Building and Environment, 2012)
Field investigations reporting increased airborne particles concentrations after ventilation duct cleaning (DC) and emissions of biocides following its use in DC highlight a need to protect building occupants from possible exposures to these harmful pollutants. A new protocol was developed to include tests for assessing duct surface cleanliness and harmful airborne pollutant concentrations associated with DC. Two office buildings undergoing DC were chosen to demonstrate the protocol application. The new protocol was tested for surface cleanliness assessment using a combination of visual inspection and a vacuum test method wherever possible. For airborne pollutant concentration assessments, indoor air exposures to total particle, fungi and VOCs were measured. The test application demonstrates that it is possible to determine harmful airborne pollutant concentration levels attributed to DC activities while still maintaining industrial performance standards of surface cleanliness.
Keywords: Duct cleaning; Test protocol; Airborne; Biocides; Particles; Surface cleanliness

Long-term hygrothermal performance of white and black roofs in North American climates - Saber, Hamed H.; Swinton, Michael C.; Kalinger, Peter; Paroli, Ralph M. (Building and Environment, 2012)
When solar radiation hits a roof surface, a part of solar energy is reflected and part is absorbed. The absorbed part of solar energy results in an increase of the surface temperature of the roof. Cool reflective (white) roofs use bright surfaces to reflect a significant portion of the incident short-wave solar radiation, which lowers the surface temperature compared to conventional (black) roofs with bituminous membrane. As such, white roofs help reduce the urban heat island effect during the summer. The question is “do white roofs lead to moisture-related problems in northern and southern climates?” To help answer this question, numerical simulations were conducted to compare the hygrothermal performance of a single kind of white and black roofs under different outdoor and indoor conditions. The outdoor conditions are obtained from the weather database of the National Research Council of Canada, Institute for Research in Construction (NRC–IRC). The indoor conditions are taken based on the European standard (EN 15026) and ASHRAE recommendations for conditioned space. The type of roofs considered in this study is Modified-Bitumen (MOD-BIT) roofing systems. The numerical simulations were conducted for the outdoor climate of Toronto (ON), Montreal (QC), St John’s (NL), Saskatoon (SK), Seattle (WA), Wilmington (NC) and Phoenix (AZ). Results showed that for the outdoor climates of St John’s and Saskatoon, the white roofs could lead to longer-term moisture-related problems. However, for the outdoor climates of Toronto, Montreal, Seattle, Wilmington and Phoenix, buildings with white roofs were shown to have a low risk of experiencing moisture damage. Also, buildings with white roofs in these locations were predicted to show a net yearly energy savings compared to buildings with black roofs.
Keywords: White cool roof; Black roof; Energy savings; Moisture accumulation; Hygrothermal modelling; Modified-Bitumen (MOD-BIT) roof

2-BFI ameliorates EAE-induced mouse spinal cord damage: effective therapeutic time window and possible mechanisms - Li, Fang; Zhang, Zheng-Xue; Liu, Yin-Feng; Xu, Hui-Gin; Hou, Sheng-Tao; Zheng, Rong-Yuan (Brain Research, 2012)
Our previous studies showed that ligands to type 2 imidazoline receptors (I2R), including 2-(2-Benzofuranyl)-2-imidazoline (2-BFI) and Idazoxan, were effective in reducing spinal cord inflammation caused by experimental autoimmune encephalomyelitis (EAE). In the present study, we determined the effective therapeutic time window of 2-BFI and found that administration of 2-BFI in mice before the appearance of ascending flaccid paralysis (1–10 days post immunization), but not during the period when neurological deficits occurred (11–20 days post immunization), significantly ameliorated EAE-induced neurobehavioral deficits, reduced the infiltration of inflammatory cells into the spinal cord, and reduced the level of demyelination. More interestingly, giving 2-BFI during 1–10 days post immunization selectively suppressed IL-17 levels in the peripheral blood, which strongly suggests that IL-17 may be a good early marker to indicate EAE progression and that 2-BFI may target CD4+ T lymphocytes, especially Th17 cells to reduce IL-17 expression. Collectively, these studies led us to envisage that 2-BFI can be a useful drug to treat multiple sclerosis (MS) when used in combination with an early indicator of MS progression, such as IL-17.
Keywords: EAE; 2-BFI; Inflammatory cytokines; IL-17; IFN-γ; IL-10; Multiple sclerosis; Therapeutic time window

The structures of three metabolites of the algal hepatotoxin okadaic acid produced by oxidation with human cytochrome P450 - Liu, Li; Guo, Fujiang; Crain, Sheila; Quilliam, Michael A.; Wang, Xiaotang; Rein, Kathleen S. (Bioorganic & Medicinal Chemistry, 2012)
Four metabolites of okadaic acid were generated by incubation with human recombinant cytochrome P450 3A4. The structures of two of the four metabolites have been determined by MS/MS experiments and 1D and 2D NMR methods using 94 and 133 μg of each metabolite. The structure of a third metabolite was determined by oxidation to a metabolite of known structure. Like okadaic acid, the metabolites are inhibitors of protein phosphatase PP2A. Although one of the metabolites does have an α,β unsaturated carbonyl with the potential to form adducts with an active site cysteine, all of the metabolites are reversible inhibitors of PP2A.
Keywords: Okadaic acid; Dinoflagellate; Algal toxin; Xenobiotic metabolism; Cytochrome P450

Switchable hydrophilicity solvents for lipid extraction from microalgae for biofuel production - Boyd, Alaina R.; Champagne, Pascale; Mcginn, Patrick J.; Macdougall, Karen M.; Melanson, Jeremy E.; Jessop, Philip G. (Bioresource Technology, 2012)
A switchable hydrophilicity solvent (SHS) was studied for its effectiveness at extracting lipids from freeze-dried samples of Botryococcus braunii microalgae. The SHS N,N-dimethylcyclohexylamine extracted up to 22 wt.% crude lipid relative to the freeze-dried cell weight. The solvent was removed from the extract with water saturated with carbon dioxide at atmospheric pressure and recovered from the water upon de-carbonation of the mixture. Liquid chromatography–mass spectrometry (LC–MS) showed that the extracted lipids contained high concentrations of long chain tri-, di- and mono-acylglycerols, no phospholipids, and only 4–8% of residual solvent. Unlike extractions with conventional organic solvents, this new method requires neither distillation nor the use of volatile, flammable or chlorinated organic solvents.
Keywords: Switchable solvents; Microalgae; Botryococcus braunii; Lipids; Biofuel

Reduction of the immunostainable length of the hippocampal dentate granule cells’ primary cilia in 3xAD-transgenic mice producing human Aβ1-42 and tau - Chakravarthy, Balu; Gaudet, Chantal; Ménard, Michel; Brown, Leslie; Atkinson, Trevor; Laferla, Frank M.; Ito, Shingo; Armato, Ubaldo; Dal Prà, Ilaria; Whitfield, James (Biochemical and Biophysical Research Communications, 2012)
The hippocampal dentate gyrus is one of the two sites of continuous neurogenesis in adult rodents and humans. Virtually all dentate granule cells have a single immobile cilium with a microtubule spine or axoneme covered with a specialized cell membrane loaded with receptors such as the somatostatin receptor 3 (SSTR3), and the p75 neurotrophin receptor (p75NTR). The signals from these receptors have been reported to stimulate neuroprogenitor proliferation and the post-mitotic maturation of newborn granule cells into functioning granule cells. We have found that in 6–24-months-old triple transgenic Alzheimer’s disease model mice (3xTg-AD) producing both Aβ1-42 and the mutant human tau protein tauP301L, the dentate granule cells still had immunostainable SSTR3- and p75NTR-bearing cilia but they were only half the length of the immunostained cilia in the corresponding wild-type mice. However, the immunostainable length of the granule cell cilia was not reduced either in 2xTg-AD mice accumulating large amounts of Aβ1-42 or in mice accumulating only a mutant human tau protein. Thus it appears that a combination of Aβ1-42 and tau protein accumulation affects the levels of functionally important receptors in 3xTg-AD mice. These observations raise the important possibility that structural and functional changes in granule cell cilia might have a role in AD.
Keywords: Alzheimer’s disease; Dentate granule cells; Primary cilium; p75NTR; Somatostatin receptor 3 (SSTR3); 3xTg-AD mice

Neurovascular protection conferred by 2-BFI treatment during rat cerebral ischemia - Han, Zhao; Cheng, Zhao-Hui; Liu, Shuang; Yang, Jin-Long; Xiao, Mei-Juan; Zheng, Rong-Yuan; Hou, Sheng-Tao (Biochemical and Biophysical Research Communications, 2012)
Stroke is caused by vascular dysfunction and currently there are no effective therapeutics to stroke induced brain damage. In contrast to an intense emphasis on neuroprotection, relatively few studies have addressed means of vascular protection in cerebral ischemia. Here we discovered that the ligand to immidazolin receptor, 2-BFI, not only provided potent neuroprotection during middle cerebral artery occlusion in rat, which confirmed our previous reports, but also protected the integrity of the cerebral vasculature. Treatment with 2-BFI twice daily after the occlusion of the middle cerebral artery for 14 d significantly improved the neurological deficits, reduced brain infarction, and importantly, protected the cerebral vasculature as evidenced by the increased expression of an endothelial marker, von Willebrand factor, and better preservation of the cerebral vasculature, as viewed under a confocal microscope on rat brain perfused with FITC-labeled dextran. These results indicated that 2-BFI contributes to protection of neurovasculature. Understanding the molecular mechanisms could eventually lead to development of more effective therapies for stroke.
Keywords: Focal cerebral ischemia; 2-(2-Benzofu-ranyl)-2-imidazoline; 2-BFI; Middle cerebral artery occlusion model; FITC-dextran

Identification of protein kinase C inhibitory activity associated with a polypeptide isolated from a phage display system with homology to PCM-1, the pericentriolar material-1 protein - Chakravarthy, Balu; Ménard, Michel; Brown, Leslie; Atkinson, Trevor; Whitfield, James (Biochemical and Biophysical Research Communications, 2012)
We had previously identified a protein kinase C (PKC) inhibitor in murine neuroblastoma cells (Chakravarthy et al. [1]). Similar PKC inhibitory activity was also found in adult rat brain. Using polyclonal antibodies raised against the partially purified PKC inhibitor from rat brain as bait, we isolated a putative brain PKC inhibitor using a T-7 phage display system expressing human brain cDNA library. After enriching the phage population expressing the putative PKC inhibitor with four rounds of biopanning using ELISA and in vitro PKC binding assays, we identified a phage clone that expressed a product with significant PKC inhibitory activity. We have cloned and expressed this cDNA in a bacterial system and purified the recombinant protein. This polypeptide (174 amino acids) is highly homologous to a region of the 228-kDa PCM-1, the human pericentriolar material 1 protein. We have mapped this polypeptide’s PKC-inhibitory domain and shown its PKC inhibitory activity in vitro. However, it will need to be determined whether the full-length PCM-1 protein possesses PKC inhibitory activity in vivo, and if so, how this might contribute to PCM-1’s recently demonstrated roles in ciliogenesis and neurogenesis.
Keywords: Protein kinase C (PKC); Inhibitor; Phage display; Pericentriolar material-1 (PCM-1) protein

Ethyl-eicosapentaenoate (E-EPA) attenuates motor impairments and inflammation in the MPTP-probenecid mouse model of Parkinson's disease - Luchtman, D. W.; Meng, Q.; Song, C. (Behavioural Brain Research, 2012)
Parkinson's disease (PD) is a neurodegenerative disorder, characterized by hypokinesia, but also mood and cognitive disorders. Neuropathologically, PD involves loss of nigrostriatal dopamine (DA) and secondary non-dopaminergic abnormalities. Inflammation may contribute to PD pathogenesis, evident by increased production of pro-inflammatory cytokines. PD onset has been positively associated with dietary intake of omega-(n)-6 polyunsaturated fatty acids (PUFA). On the other hand, omega-(n)-3 PUFA may benefit PD. One of these n-3 PUFA, eicosapentaenoic acid (EPA), is a neuroprotective lipid with anti-inflammatory properties, but its neuroprotective effects in PD are unknown. Thus, we presently tested the hypothesis that EPA can protect against behavioral impairments, neurodegeneration and inflammation in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-probenecid (MPTP-P) mouse model of PD. MPTP-P injections caused hypokinesia in the rotorod and pole test, hyperactivity in the open field, and impaired mice on the cued version (procedural memory) of the Morris water maze. MPTP-P caused a loss of nigrostriatal DA and altered neurochemistry in the frontal cortex and hippocampus. Furthermore, striatal levels of pro-inflammatory cytokines were increased, while the brain n-3/n-6 lipid profile remained unaltered. Feeding mice a 0.8% ethyl-eicosapentaenoate (E-EPA) diet prior to MPTP-P injections increased brain EPA and docosapentaenoic acid (DPA) but not docosahexaenoic acid (DHA) or n-6 PUFA. The diet attenuated the hypokinesia induced by MPTP-P and ameliorated the procedural memory deficit. E-EPA also suppressed the production of pro-inflammatory cytokines. However, E-EPA did not prevent nigrostriatal DA loss. Based on this partial protective effect of E-EPA, further testing may be warranted.
Keywords: Parkinson's disease; 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Eicosapentaenoic acid; Behavior; Neurotransmitters; Inflammation

Phthalocyanine tetrasulfonates bind to multiple sites on natively-folded prion protein - Dee, Derek R.; Gupta, Amar Nath; Anikovskiy, Max; Sosova, Iveta; Grandi, Elena; Rivera, Laura; Vincent, Abhilash; Brigley, Angela M.; Petersen, Nils O.; Woodside, Michael T. (Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics, 2012)
The phthalocyanine tetrasulfonates (PcTS), a class of cyclic tetrapyrroles, bind to the mammalian prion protein, PrP. Remarkably, they can act as anti-scrapie agents to prevent the formation and spread of infectious, misfolded PrP. While the effects of phthalocyanines on the diseased state have been investigated, the interaction between PcTS and PrP has not yet been extensively characterized. Here we use multiple, complementary assays (surface plasmon resonance, isothermal titration calorimetry, fluorescence correlation spectroscopy, and tryptophan fluorescence quenching) to characterize the binding of PcTS to natively-folded hamster PrP(90–232), in order to determine binding constants, ligand stoichiometry, influence of buffer ionic strength, and the effects of chelated metal ions. We found that binding strength depends strongly on chelated metal ions, with Al³+ -PcTS binding the weakest and free-base PcTS the strongest of the three types tested (Al³+, Zn²+, and free-base). Buffer ionic strength also affected the binding, with Kd increasing along with salt concentration. The binding isotherms indicated the presence of at least two different binding sites with micromolar affinities and a total stoichiometry of ~ 4–5 PcTS molecules per PrP molecule.
Keywords: Prion protein; Phthalocyanine tetrasulfonate; Ligand binding; ITC; SPR; Fluorescence correlation spectroscopy

Composition of the mitochondrial electron transport chain in Acanthamoeba castellanii: structural and evolutionary insights - Gawryluk, Ryan M. R.; Chisholm, Kenneth A.; Pinto, Devanand M.; Gray, Michael W. (Biochimica et Biophysica Acta (BBA) - Bioenergetics, 2012)
The mitochondrion, derived in evolution from an α-proteobacterial progenitor, plays a key metabolic role in eukaryotes. Mitochondria house the electron transport chain (ETC) that couples oxidation of organic substrates and electron transfer to proton pumping and synthesis of ATP. The ETC comprises several multiprotein enzyme complexes, all of which have counterparts in bacteria. However, mitochondrial ETC assemblies from animals, plants and fungi are generally more complex than their bacterial counterparts, with a number of ‘supernumerary’ subunits appearing early in eukaryotic evolution. Little is known, however, about the ETC of unicellular eukaryotes (protists), which are key to understanding the evolution of mitochondria and the ETC. We present an analysis of the ETC proteome from Acanthamoeba castellanii, an ecologically, medically and evolutionarily important member of Amoebozoa (sister to Opisthokonta). Data obtained from tandem mass spectrometric (MS/MS) analyses of purified mitochondria as well as ETC complexes isolated via blue native polyacrylamide gel electrophoresis are combined with the results of bioinformatic queries of sequence databases. Our bioinformatic analyses have identified most of the ETC subunits found in other eukaryotes, confirming and extending previous observations. The assignment of proteins as ETC subunits by MS/MS provides important insights into the primary structures of ETC proteins and makes possible, through the use of sensitive profile-based similarity searches, the identification of novel constituents of the ETC along with the annotation of highly divergent but phylogenetically conserved ETC subunits.
Keywords: Mitochondrion; Protist; Electron transport chain; Mass spectrometry

A loosely coupled system integration approach for decision support in facility management and maintenance - Shen, Weiming; Hao, Qi; Xue, Yunjiao (Automation in Construction, 2012)
With the objective of providing the best decision support to facility management and maintenance, this paper presents an agent-based, serviced-oriented approach for integrating data, information, and knowledge captured and accumulated during the entire facility lifecycle from its project planning, design, construction, material/component/equipment procurement, to operation and maintenance. All data/information/knowledge sources and hardware/software applications are loosely integrated through agent-based web services, either proactive or reactive, to provide decision support over all stages of the facility lifecycle, and particularly to optimize facility operations and maintenance. Case studies have been conducted with proof-of-concept prototype implementations to validate the proposed approach.
Keywords: Facility lifecycle information integration; Facility management and maintenance; Decision support; Service-oriented architecture; Software agents

Comparison of standards for predicting ice forces on arctic offshore structures - Frederking, Robert (The Proceedings of the Tenth (2012) ISOPE Pacific/Asia Offshore Mechanics Symposium, 2012)
Ice force predictions using the ISO 19906 Arctic offshore structures standard and three national standards have been compared for structures offshore Sakhalin. A multi-leg structure with leg diameters 18 and 24 m subjected to several design ice conditions, level ice 1.2 m, rafted ice 3.5 m and a first year ridge keel 21 m deep was evaluated. ISO 19906 is the most complete and transparent standard in providing guidance. It incorporates guidance on ice strength from the Russian standard, and ice thickness and geometry effects from the Canadian standard. Further guidance is still needed for multi-leg structures.
Keywords: ice structure interaction; ice forces; offshore structures standards

Frailty and survival of older Chinese adults in urban and rural areas: Results from the Beijing Longitudinal Study of Aging - Yu, Pulin; Song, Xiaowei; Shi, Jing; Mitnitski, Arnold; Tang, Zhe; Fang, Xianghua; Rockwood, Kenneth (Archives of Gerontology and Geriatrics, 2012)
Differences in frailty between rural and urban older adults have been demonstrated in developed countries. It is not understood how the apparently greater differences in living conditions between different types of regions in China may affect health and outcomes of older Chinese adults. Here, a frailty index (FI) based on the accumulation of health deficits was used to investigate health and survival differences in older Chinese men and women. We studied rural (n = 1121) and urban (n = 2136) older adults (55–97 years old) in the Beijing Longitudinal Study of Aging (BLSA), of whom 48.9% (rural) and 35.4% (urban) died over 8 years of follow-up. The FI was generated from 35 self-reported health deficits. The mean FI increased exponentially with age (r² = 0.87) and was higher in women than in men. The death rate increased significantly with increases in the FI, but women showed a lower death rate than did men. The mean FI in urban older adults (0.12 ± 0.10) was lower than that in their rural counterparts (0.14 ± 0.12, p < 0.001). Urban dwellers showed better survival compared with their counterparts in the rural areas. Adjusted by age, sex, and education level, the hazard ratio for death for each increment of the FI was 1.28 for urban people and 1.27 for rural people. Chinese urban dwellers showed better health and survival than rural dwelling older adults. The FI readily summarized health and mortality differences among different geographic regions, reflecting the impact of the environment, socioeconomics, and medical services on deficit accumulation and on survival.
Keywords: Aging; Frailty index; Geographic areas; Rural; Urban; China; Frailty

Effect of strain and ploidy on growth performance of Atlantic salmon, Salmo salar, following seawater transfer - Sacobie, Charles F. D.; Glebe, Brian D.; Barbeau, Myriam A.; Lall, Santosh P.; Benfey, Tillmann J. (Aquaculture, 2012)
This study examined the effects of strain and ploidy on the growth of Atlantic salmon Salmo salar post-smolts in a 12-week tank trial, using specific growth rate (SGR), condition factor (CF) and plasma insulin-like growth factor I (IGF-I) as indicators of growth. Five strain/ploidy combinations (“populations”) were evaluated: triploids of two domesticated strains (Canadian-origin “Cascade” and Norwegian-origin “Mowi”) and diploids of the same Mowi strain, a top-performing Bay of Fundy commercial strain derived from St. John River stock (SJR, New Brunswick, Canada) and SJR wild origin. All fish were individually PIT-tagged and then reared in 150 L tanks (3 tanks per population), with individual size measurements recorded every 4 weeks. Wild SJR diploids consistently had the highest SGR, higher even than their domesticated counterparts, and triploid Cascades had the lowest. Ploidy did not affect the SGR of Mowi fish, which tended to be intermediate between wild and domesticated SJR diploids. CF at the end of the study followed a similar pattern, with wild and commercial SJR diploids having the highest CF, followed by diploid Mowi, triploid Mowi and triploid Cascade fish. Plasma IGF-I levels increased from the initial sampling to the end of the growth trial for all populations except the commercial SJR diploids, which maintained the highest levels throughout the study. The observations that (a) there can be significant variation among strains for triploid SGR and (b) some wild strains can outperform their domesticated counterparts as diploids, at least under experimental conditions, provide important information to salmon farmers on the successful use of triploids and the need for continued research into broodstock development.
Keywords: Triploidy; Atlantic salmon; Insulin-like growth factor-I; Wild and farmed salmon; Mowi; St. John River; Cascade

Water condensation on superhydrophobic aluminum surfaces with different low-surface-energy coatings - Yin, Long; Wang, Yuanyi; Ding, Jianfu; Wang, Qingjun; Chen, Qingmin (Applied Surface Science, 2012)
In this work, we have fabricated superhydrophobic aluminum surfaces by a facile chemical etching method. Surface morphology and composition were studied by using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). To comparatively investigate the effect of environmental factors on superhydrophobic behaviors of surfaces with different low-surface-energy coatings under controllable condensation conditions, contact and sliding angles were measured from −10 °C to 30 °C under relative humidity (RH) of 30, 60 and 90%, respectively. The calculation of the solid–liquid contact area fraction quantitatively explained the increased wettability characterized by descending contact angle and ascending sliding angle under low temperature and high humidity, and indicated a transition of the equilibrium state from Cassie–Baxter to Wenzel on rough surfaces. The wettability restoration test showed that the loss of superhydrophobicity during condensation could be recovered completely after a drying process at room temperature.
Keywords: Superhydrophobic; Condensation; Contact angle; Sliding angle; Surface temperature; Relative humidity

Measurement of 56Fe activity produced in inelastic scattering of neutrons created by cosmic muons in an iron shield - Krmar, M.; Jovančević, N.; Nikolić, D. (Applied Radiation and Isotopes, 2012)
We report on the study of the intensities of several gamma lines emitted after the inelastic scattering of neutrons in 56Fe. Neutrons were produced via nuclear processes induced by cosmic muons in the 20 tons massive iron cube placed at the Earth's surface and used as a passive shield for the HPGe detector. Relative intensities of detected gamma lines are compared with the results collected in the same iron shield by the use of the 252Cf neutrons. Assessment against the published data from neutron scattering experiments at energies up to 14 MeV is also provided. It allowed us to infer the qualitative information about the average energy of muon-created neutrons in the iron shield.
Keywords: Low background γ spectroscopy; Background radiation; Muon-induced nuclear reactions; Inelastic neutron scattering; Cosmic muons

Numerical estimation of the effective electrical conductivity in carbon paper diffusion media - Zamel, Nada; Li, Xianguo; Shen, Jun (Applied Energy, 2012)
The transport of electrons through the gas diffusion layer (GDL) of polymer electrolyte membrane (PEM) fuel cells has a significant impact on the optimal design and operation of PEM fuel cells and is directly affected by the anisotropic nature of the carbon paper material. In this study, a three-dimensional reconstruction of the GDL is used to numerically estimate the directional dependent effective electrical conductivity of the layer for various porosity values. The distribution of the fibers in the through-plane direction results in high electrical resistivity; hence, decreasing the overall effective electrical conductivity in this direction. This finding is in agreement with measured experimental data. Further, using the numerical results of this study, two mathematical expressions were proposed for the calculation of the effective electrical conductivity of the carbon paper GDL. Finally, the tortuosity factor was evaluated as 1.7 and 3.4 in the in- and through-plane directions, respectively.
Keywords: Effective electrical conductivity; Gas diffusion layer; PEM fuel cells; Carbon paper

Using pyridine as nitrogen-rich precursor to synthesize Co-N-S/C non-noble metal electrocatalysts for oxygen reduction reaction - Qiao, Jinli; Xu, Li; Ding, Lei; Zhang, Lei; Baker, Ryan; Dai, Xianfeng; Zhang, Jiujun (Applied Catalysis B: Environmental, 2012)
The development of non-noble metal catalysts is of great interest due to their significant potential application in both fuel cell systems and metal–air batteries, particularly when considering long term commercial deployment. In this regard, novel Co-N-S/C non-noble metal catalysts supported on carbon, are synthesized in this study using a solvent-milling method followed by heat-treatment at elevated temperatures. Pyridine is used as the nitrogen-rich ligand for Co-Nx precursor complex formation. The morphology and composition of the catalyst are characterized by X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM) as well as X-ray photoelectron spectroscopy (XPS). Several catalysts containing different amounts of Co are also synthesized. The optimal Co content is found to be in the range of 10–15 wt% nominal, in terms of catalytic oxygen reduction reaction (ORR) activity. This catalyst shows high electroactivity for the ORR with a high stability in alkaline media. Using rotating disk electrode measurements, and Koutechy–Levich analysis, the overall electron transfer number in the catalyzed ORR is found to be 3.8–4.0, suggesting the catalyzed ORR is a four-electron transfer process from O2 to H2O.
Keywords: Non-noble metal catalysts; Cobalt; Pyridine; Oxygen reduction reaction; Fuel cells; Metal–air batteries

Effects of edge screens on the absorption of blocks of theatre chairs - Choi, YoungJi; Bradley, John S.; Jeong, DaeUp (Applied Acoustics, 2012)
This paper reports new measurement results investigating the use of screens around samples of theatre chairs to minimize edge effects when measuring theatre chair absorption in reverberation chambers. The absorption measurements included both full scale and scale model measurements in reverberation chambers and a model recital hall. The use of screens has been proposed to better approximate the sound absorption of the larger blocks of chairs in auditoria. The method of measuring the absorption of blocks of chairs with screens around their edges and located in the corner of a reverberation chamber did not give results indicative of the values obtained for larger areas in auditoria. The addition of screens around samples of chairs did not eliminate the variation of absorption coefficients with perimeter/area ratio. The results of extrapolations from measurements of blocks of screened chairs to infinite samples gave lower absorption coefficients than found for blocks of unscreened chairs. The absorption of chairs in large performance halls can best be predicted using the P/A method to extrapolate from reverberation chamber measurements of smaller samples of unscreened chairs, with a range of P/A values, to the larger samples and lower P/A ratios of blocks of chairs typical of performance spaces.
Keywords: Absorption coefficients; Theatre chairs; Edge effects; Screens; Perimeter to area ratio

Degradation and drug release in calcium polyphosphate bioceramics: An MRI-based characterization - Bray, J. M.; Filiaggi, M. J.; Bowen, C. V.; Beyea, S. D. (Acta Biomaterialia, 2012)
Degradable, bioceramic bone implants made of calcium polyphosphate (CPP) hold potential for controlled release of therapeutic agents in the treatment of localized bone disease. Magnetic resonance imaging techniques for non-invasively mapping fluid distribution, T1 and T2 relaxation times and the apparent diffusion coefficient were performed in conjunction with a drug elution protocol to resolve free and bound water components within the material microstructure in two CPP formulations (G1 and G2). The T2 maps provided the most accurate estimates of free and bound water, and showed that G1 disks contained a detectable free water component at all times, with drug release dominated by a Fickian diffusion mechanism. Drug release from G2 disks was characterized by a combined diffusional/structural relaxation mechanism, which may be related to the gradual infiltration of a free water component associated with swelling and/or chemical degradation.
Keywords: Magnetic resonance imaging; Controlled release; Calcium polyphosphate; Bioceramics

Review of standards for ice forces on port structures - Frederking, R. (Cold Regions Engineering 2012 (15th International Conference on Cold Regions Engineering), 2012)
Port structures in cold regions generally take the form of large caisson structures or piled structures. There are limited standards for such structures, so the following standards for highway bridges and offshore structures were assessed for application in specifying ice forces on port structures; CSA-S6 Canadian Highway Bridge Design Code, ISO 19906 Arctic offshore structures, CSA-S471 General requirements, design criteria, the environment, and loads, API Recommended Practice 2N Planning, Designing, and Constructing Structures and Pipelines for Arctic Conditions (1995), and Russia’s SNiP 2.06.04-82* Loads and Effects on Hydrotechnical Structures. The ice condition considered was level ice 0.2 to 2 m thick. Three typical structures were evaluated; 1 m diameter pile, 4 m diameter structure and a 50 m wide structure. CSA S6 was found to be best suited for small pile structures (~1 m dia.). For slightly larger structures (~4 m dia.), CSA S6 was the best choice, but ISO 19906 and CSA S471 could be used for ice thickness greater than 1.2 m. Finally, for wide structures CSA S471 was most suitable, but ISO 19906 or API RP 2N could be used for ice thickness greater than 0.6 m and up to 2 m.
Keywords: Ice forces; standards; structures

Evaluation of Calanus finmarchicus copepod meal in practical diets for juvenile Atlantic halibut (Hippoglossus hippoglossus) - Colombo-Hixson, S. M.; Olsen, R. E.; Tibbetts, S. M.; Lall, S. P. (Aquaculture Nutrition, 2012)
The copepod, Calanus finmarchicus, has potential as a new ingredient in practical feeds for marine fish. Two experiments were conducted to evaluate the nutritional value of C. finmarchicus meals when fed to juvenile Atlantic halibut. The first study determined protein, lipid and energy digestibility coefficients of four C. finmarchicus meals prepared under different processing conditions. The second study evaluated growth and nutrient utilization efficiency of juveniles fed diets containing varying proportions of fish meal, plant meals and C. finmarchicus meal. Moisture, ash, protein, lipid and gross energy contents of the C. finmarchicus meals were 28–93, 74–138, 505–648, 123–269 g kg-¹, and 21–26 MJ kg-¹, respectively. Protein, lipid and energy digestibilities of C. finmarchicus meals were 91–99%, 90–95% and 90–99%. The digestibilities significantly decreased for the Calanus meals processed at higher temperatures. During the growth study, halibut fed a diet containing 240 g kg-¹ C. finmarchicus meal had significantly higher weight gain and growth rate than all other groups. Nitrogen and energy retention efficiencies ranged between 35–45% and 33–43%, and were significantly higher for fish fed 160–240 g kg-¹ C. finmarchicus meal than for fish fed plant protein and control diets. The results indicate that growth and nutrient utilization efficiency are improved in Atlantic halibut fed diets supplemented with C. finmarchicus meal.
Keywords: Atlantic halibut; Calanus finmarchicus; digestibility; protein; zooplankton

Gravitational collapse of rectangular granular piles - Babaei, M. H.; Dabros, T.; Savage, S. B. (Proceedings of the 2012 COMSOL Conference, 2012)
In this study, the dam-break type two-dimensional gravitational collapse of rectangular granular piles in air was numerically studied. The frictional behavior of the material was based on the von Mises model with the Mohr-Coulomb yield surface leading to pressure and strain-rate-dependence of shear viscosity. The governing equations of the problem were solved using the COMSOL two-phase flow CFD Module with the level-set method used for accurate tracking of interfaces. This model successfully captured the stable heaps formed at the end of the collapse. The evolutions of shape and velocity field for collapsing piles of two different initial pile orientations (aspect ratios) were investigated. The comparison of the final shapes of the collapsed piles was in accordance with the experimental measurements available in the literature.
Keywords: gravitational collapse; granular pile; two-phase flow; von Mises yield function; Mohr-Coulomb yield surface; CFD

The binomial distribution of hydrogen and deuterium in arsanes, diarsanes, and triarsanes generated from As(Ιιι)/[BHnD4-n]− and the effect of trace amounts of Rh(Ιιι) ions - Pagliano, Enea; D’Ulivo, Alessandro; Mester, Zoltán; Sturgeon, Ralph E.; Meija, Juris (Journal of The American Society for Mass Spectrometry, 2012)
Recent studies of the formation of arsane in the borohydride/arsenate reaction demonstrate the occurrence of condensation cascades whereby small quantities of di- and triarsanes are formed. In this study, the isotopic composition of these di- and triarsanes was examined using deuterium labelled borohydrides. A statistical model was employed to construct the mass spectra of all diarsane and triarsane isotopologues (As2H n D4-n and As3H n D5-n) from the mass spectra of isotopically pure compounds (As2H4, As2D4, As3H5, and As3D5). Subsequent deconvolution of the experimental mixed spectra shows that incorporation of hydrogen closely follows the binomial distribution, in accord with arsane formation. The H/D distribution in arsane, diarsane, and triarsane isotopologues is binomial in the absence of any interference. However, this is significantly altered by the presence of some transition metals; presented here, for the first time, are the effects of Rh(Ιιι). The presence of Rh(Ιιι) in the As(Ιιι)/[BD4]− system entails the incorporation of hydrogen into the arsanes arising from the solvent, altering the expected binomial H/D distribution.
Keywords: hydride generation; statistical modeling; arsane, diarsane and triarsane; mechanistic interference

Iodination on tyrosine residues during oxidation with sodium periodate in solid phase extraction of N-linked glycopeptides - Cohen, Alejandro M.; Kostyleva, Ripsik; Chisholm, Kenneth A.; Pinto, Devanand M. (Journal of The American Society for Mass Spectrometry, 2012)
Solid-phase extraction of N-linked glycopeptides (SPEG) using hydrazide-modified supports has become a common sample preparation procedure in glycoproteomic experiments. We demonstrate that iodination of tyrosine residues occur in SPEG as a side reaction during an oxidation step with sodium periodate. MS/MS analysis of oxidized bovine serum albumin and carbonic anhydrase digests revealed a characteristic shift of m/z 125.9 on all y and b fragment ions containing the modified tyrosine residues. Selected reaction monitoring (SRM) measurements showed that the peak intensity from of the iodinated peptides increased during the course of oxidation. After an hour of oxidation, SRM analysis revealed that the strongest signal from an iodinated peptide was approximately one-tenth of the intensity of the corresponding unmodified peptide. Iodinated tyrosine residues were also identified in serum samples subjected to SPEG and analyzed by LC-ESI-MS/MS. We recommend assessing this side reaction by including iodotyrosine as a variable modification when performing database searches on SPEG experiments. For SRM-based acquisitions, we encourage the avoidance of tyrosine-containing glycopeptides or, if this is not practical, monitoring transitions that contain the potential modified iodinated tyrosine residue to monitor the presence of the iodinated form of the glycopeptide.
Keywords: Glycoproteomics; Iodination; N-linked glycoproteins; Hydrazide modified solid phase extraction; Oxidation; Sodium periodate

Expression of recombinant Atlantic salmon serum C-type lectin in Drosophila melanogaster Schneider 2 cells - Uribe, Elke; Venkatesan, Meenakshi; Rose, David R.; Ewart, Kathryn Vanya (Cytotechnology, 2012)
The Atlantic salmon (Salmo salar) serum lectin (SSL) is a soluble C-type lectin that binds bacteria, including salmon pathogens. This lectin is a cysteine-rich oligomeric protein. Consequently, a Drosophila melanogaster expression system was evaluated for use in expressing SSL. A cDNA encoding SSL was cloned into a vector designed to express it as a fusion protein with a hexahistidine tag, under the control of the Drosophila methallothionein promoter. The resulting construct was stably transfected into Drosophila S2 cells. After CdCl2 induction, transfected S2 cells secreted recombinant SSL into the cell culture medium. A cell line derived from stably transformed polyclonal cell populations expressing SSL was used for large-scale expression of SSL. Recombinant SSL was purified from the culture medium using a two-step purification scheme involving affinity binding to yeast cells and metal-affinity chromatography. Although yields of SSL were very low, correct folding and functionality of the recombinant SSL purified in this manner was demonstrated by its ability to bind to Aeromonas salmonicida. Therefore, Drosophila S2 cells may be an ideal system for the production of SSL if yields can be increased.
Keywords: Atlantic salmon; C-type lectin; Drosophila; Innate immunity; Protein expression; Protein purification; Salmo salar

Effect of Si and Fe doping on calcium phosphate glass fibre reinforced polycaprolactone bone analogous composites - Mohammadi, M. Shah; Ahmed, I.; Muja, N.; Almeida, S.; Rudd, C. D.; Bureau, M. N.; Nazhat, S. N. (Acta Biomaterialia, 2012)
Reinforcing biodegradable polymers with phosphate-based glass fibres (PGF) is of interest for bone repair and regeneration. In addition to increasing the mechanical properties, PGF can also release bioinorganics, as they are water soluble, a property that may be controllably translated into a fully degradable composite. Herein, the effect of Si and Fe on the solubility of calcium-containing phosphate-based glasses (PG) in the system (50P2O5–40CaO–(10 − x)SiO2−xFe2O3, where x = 0, 5 and 10 mol.%) were investigated. On replacing SiO2 with Fe2O3, there was an increase in the glass transition temperature and density of the PG, suggesting greater crosslinking of the phosphate chains. This significantly reduced the dissolution rates of degradation and ion release. Two PG formulations, 50P2O5–40CaO–10Fe2O3 (Fe10) and 50P2O5–40CaO–5Fe2O3–5SiO2 (Fe5Si5), were melt drawn into fibres and randomly incorporated into polycaprolactone (PCL). Initially, the flexural strength and modulus significantly increased with PGF incorporation. In deionized water, PCL–Fe5Si5 displayed a significantly greater weight loss and ion release compared with PCL–Fe10. In simulated body fluid, brushite was formed only on the surface of PCL–Fe5Si5. Dynamic mechanical analysis in phosphate buffered saline (PBS) at 37 °C revealed that the PCL–Fe10 storage modulus (E′) was unchanged up to day 7, whereas the onset of PCL–Fe5Si5 E′ decrease occurred at day 4. At longer-term ageing in PBS, PCL–Fe5Si5 flexural strength and modulus decreased significantly. MC3T3-E1 preosteoblasts seeded onto PCL–PGF grew up to day 7 in culture. PGF can be used to control the properties of biodegradable composites for potential application as bone fracture fixation devices.
Keywords: Phosphate-based glass fibres; Biodegradable composites; Bioactivity; Preosteoblast; Tissue engineering

Engineered peptides with enzymatically cleavable domains for controlling the release of model protein drug from “soft” nanoparticles - Singh, Harsh Deep; Bushnak, Ibraheem; Unsworth, Larry D. (Acta Biomaterialia, 2012)
Matrix metalloproteinase-2 (MMP-2) is an endopeptidase that has been shown to be present in high concentrations during most tissue remodeling events, including disease states like active tumor sites, thus making it an attractive molecule for use in effecting local delivery of therapeutic molecules. Moreover, the use of non-toxic and biodegradable nanoparticles for controlled drug delivery is highly sought after. To this end, bovine serum albumin (BSA) nanoparticles (NPs) were stabilized with coatings formed using domains of varying sensitivity to MMP-2, viz. K6GPQG/IASQK6 and K6HPVG/LLARK6, lysine residues being used to facilitate peptide immobilization to the BSA NPs via electrostatic interactions, and peptide domains that have a high (HPVG/LLAR) and low (GPQG/IASQ) MMP-2 cleavage rate. The MMP-2-induced cleavage rates of these two domains (the position of action being noted with a “/”) have differing kinetics that can be used to provide a novel mechanism for facilitating the controlled release of molecules where local concentrations of MMP-2 are high. It was found that both surface concentration and cleavage domain type influenced the release of the model drug (BSA) from these NPs. This stratagem may provide a novel pathway for developing multi-functional coatings for controlling the local delivery of therapeutics at sites where the presence of various enzymes exist as a function of tissue state.
Keywords: BSA; Coacervation; Engineered peptide; MMP-2; Controlled release strategy

TEM analysis of the microstructure in TiF3-catalyzed and pure MgH2 during the hydrogen storage cycling - Danaie, Mohsen; Mitlin, David (Acta Materialia, 2012)
We utilized transmission electron microscopy (TEM) analysis, with a cryogenically cooled sample stage, to detail the microstructure of partially transformed pure and titanium fluoride-catalyzed magnesium hydride powder during hydrogenation cycling. The TiF3-catalyzed MgH2 powder demonstrated excellent hydrogen storage kinetics at various temperatures, whereas the uncatalyzed MgH2 showed significant degradation in both kinetics and capacity. TEM analysis on the partially hydrogen absorbed and partially desorbed pure Mg(MgH2) revealed a large fraction of particles that were either not transformed at all or were completely transformed. On the other hand, in the MgH2+TiF3 system it was much easier to identify regions with both the hydride and the metal phase coexisting in the same particle. This enabled us to establish the metal hydride orientation relationship (OR) during hydrogen absorption. The OR was determined to be (1 1 0)MgH2 || (−1 1 0 −1)Mg and [−1 1 1]MgH2 || [0 1 −1 1]Mg. During absorption the number density of the hydride nuclei does not show a dramatic increase due the presence of TiF3. Conversely, during desorption the TiF3 catalyst substantially increases the number of the newly formed Mg crystallites, which display a strong texture correlation with respect to the parent MgH2 phase. Titanium fluoride also promotes extensive twinning in the hydride phase.
Keywords: Hydrogen storage; Magnesium hydride; Transmission electron microscopy

InP-based quantum dot lasers - Poole, Philip (Advances in Semiconductor Lasers, 2012)
Quantum dot-based lasers have long been predicted to have interesting properties as well as performance advantages over more conventional quantum well-based devices. The development of InP-based quantum dot lasers for use in the 1.55 μm wavelength range is discussed here. The growth of high-quality quantum dots in this wavelength range is first described, followed by their use for laser-type applications. The performance of simple Fabry–Perot lasers is discussed with demonstrations of their high-speed dynamics and advantages for amplifier applications. The large spectra bandwidth of the gain and fast dynamics are used to produce record short pulse widths and high-repetition rate mode-locked lasers. The quantum dot gain medium is also demonstrated to have interesting properties for single frequency lasers, with very narrow linewidths and high side-mode suppression ratios. Although still in its infancy, InP-based quantum dot lasers are already demonstrating high performance as well as novel characteristics.
Keywords: Laser; Quantum dot; InP; InAs; Mode locked; Semiconductor optical amplifier

A TEM based study of the microstructure during room temperature and low temperature hydrogen storage cycling in MgH2 promoted by Nb–V - Tan, XueHai; Zahiri, Beniamin; Holt, Chris M. B.; Kubis, Alan; Mitlin, David (Acta Materialia, 2012)
Magnesium hydride combined with a new bimetallic Nb–V catalyst displays remarkably rapid and stable low temperature (200 °C) hydrogen storage kinetics, even after 500 full volumetric absorption/desorption cycles. The system is also able to fairly rapidly absorb hydrogen at room temperature at a pressure of 1 bar. This unprecedented absorption behavior was demonstrated for 20 cycles. We employed extensive cryo-stage transmission electron microscopy (TEM) analysis on fully and partially sorbed materials to provide insight into the rapid Mg to MgH2 phase transformation. After extended cycling of what was initially a 1.5 μm thick fully dense alloy film, the sample structure becomes analogous to that of a weakly agglomerated nanocomposite powder. The cycled Mg–V–Nb structure consists of a dense distribution of catalytic Nb–V nanocrystallites covering the surfaces of larger Mg and MgH2 particles. The partially absorbed 20 °C and 200 °C microstructures both show this morphology. TEM results combined with Johnson–Mehl–Avrami-type kinetic analysis point to the surface catalyst distribution and stability against coarsening as being a key influence on the two-stage hydriding kinetics. Remarkably, the mean size of the Nb0.5V0.5H nanocrystallites stays essentially invariant throughout cycling; it is 3 nm after 45 cycles and 4 nm after 500 cycles. A mechanistic description is provided for the cycling-induced microstructural evolution in the ternary alloy as well as in the binary baselines.
Keywords: Hydrogen storage; Magnesium hydride; TEM; Microstructure; Catalyst

Monogalactosyldiacylglycerols, potent nitric oxide inhibitors from the marine microalga Tetraselmis chui - Banskota, Arjun H.; Gallant, Pamela; Stefanova, Roumiana; Melanson, Ronald; O'Leary, Stephen J. B. (Natural Product Research, 2012)
Methanolic extracts of some marine and freshwater microalgae were tested for their nitric oxide (NO) inhibitory activity on lipopolysaccharide-induced NO production in RAW264.7 macrophage cells. Among the tested extracts, Tetraselmis chui extract showed the strongest NO inhibitory activity, thus selected for further study. NO inhibitory activity guided isolation led to identification of two monogalactosyldiacylglycerols (MGDGs) (2S)-1-O-(6Z,9Z,12Z,15Z-octadecatetranoyl)-2-O-(4Z,7Z,10Z,13Z-hexadecatetranoyl)-3-O-β-D-galactopyranosylglycerol (1) and (2S)-1-O-(9Z,12Z,15Z-octadecatrinoyl)-2-O-(4Z,7Z,10Z,13Z-hexadecatetranoyl)-3-O-β-D-galactopyranosylglycerol (2) from the MeOH extract of T. chui. The stereo-chemistry of 1 was elucidated by classical degradation method. MGDGs 1 and 2 showed strong NO inhibitory activity compared to NG-methyl-L-arginine acetate salt, a well known NO inhibitor used as a positive control. Isolated MGDGs suppressed NO production through down-regulation of inducible NO synthase protein. A structure activity relationship study suggested that the polyunsaturated fatty acids of the MGDGs are responsible for NO inhibition. Moreover, increasing unsaturation on the fatty acid side chains enhanced the NO inhibitory potency of the MGDGs.
Keywords: monogalactosyldiacylglycerol; nitric oxide; Tetraselmis chui; iNOS; microalgae; galactolipid; glycolipid

Nitric oxide inhibitory activity of monogalactosylmonoacylglycerols from a freshwater microalgae Chlorella sorokiniana - Banskota, Arjun H.; Stefanova, Roumiana; Gallant, Pamela; Osborne, Jane A.; Melanson, Ronald; O'Leary, Stephen J. B. (Natural Product Research, 2012)
Chemical investigation of the freshwater microalgae Chlorella sorokiniana led to the isolation of a new monogalactosylmonoacylglycerol, namely, (2S)-1-O-(7Z,10Z-hexadecadienoyl)-3-O-β-D-galactopyranosylglycerol (1) together with a known glycolipid (2S)-1-O-(7Z,10Z,13Z-hexadecatrienoyl)-3-O-β-D-galactopyranosylglycerol (2). Both monogalactosylmonoacylglycerols showed dose-dependent nitric oxide (NO) inhibitory activity against lipopolysaccharide-induced NO production in RAW264.7 macrophage cells suggesting their possible use as anti-inflammatory agents.
Keywords: monogalactosylmonoacylglycerol; nitric oxide; Chlorella sorokiniana; microalgae

Linear friction welding of a near-β titanium alloy - Dalgaard, E.; Wanjara, P.; Gholipour, J.; Cao, X.; Jonas, J. J. (Acta Materialia, 2012)
The linear friction welding (LFW) behaviour of near-β titanium alloy Ti–5Al–5V–5Mo–3Cr (Ti-5553) was investigated by varying the processing conditions of frequency and axial pressure. The examined mechanical properties of the welded material included microhardness and tensile properties. The maximum strains experienced by the material during LFW for each set of welding parameters were estimated based on the process parameters and then evaluated using Aramis, a three-dimensional optical deformation measurement system. The LFWed Ti-5553 was examined with electron backscatter diffraction techniques to relate the texture and phase changes to the thermomechanical conditions. Characterisation of the welds included analysis of the microstructural features of the weld region and the thermomechanically affected zone in relation to the parent material.
Keywords: Linear friction welding; Ti-5553; Microstructure; Tensile properties

Improve accuracy and sensibility in glycan structure prediction by matching glycan isotope abundance - Xu, Guang; Liu, Xin; Liu, Qing yan; Zhou, Yanhong; Li, Jianjun (Analytica Chimica Acta, 2012)
Mass Spectrometry (MS) is a powerful technique for the determination of glycan structures and is capable of providing qualitative and quantitative information. Recent development in computational method offers an opportunity to use glycan structure databases and de novo algorithms for extracting valuable information from MS or MS/MS data. However, detecting low-intensity peaks that are buried in noisy data sets is still a challenge and an algorithm for accurate prediction and annotation of glycan structures from MS data is highly desirable. The present study describes a novel algorithm for glycan structure prediction by matching glycan isotope abundance (mGIA), which takes isotope masses, abundances, and spacing into account. We constructed a comprehensive database containing 808 glycan compositions and their corresponding isotope abundance. Unlike most previously reported methods, not only did we take into count the m/z values of the peaks but also their corresponding logarithmic Euclidean distance of the calculated and detected isotope vectors. Evaluation against a linear classifier, obtained by training mGIA algorithm with datasets of three different human tissue samples from Consortium for Functional Glycomics (CFG) in association with Support Vector Machine (SVM), was proposed to improve the accuracy of automatic glycan structure annotation. In addition, an effective data preprocessing procedure, including baseline subtraction, smoothing, peak centroiding and composition matching for extracting correct isotope profiles from MS data was incorporated. The algorithm was validated by analyzing the mouse kidney MS data from CFG, resulting in the identification of 6 more glycan compositions than the previous annotation and significant improvement of detection of weaker peaks compared with the algorithm previously reported.
Keywords: Bioinformatics; Glycan; Isotope; Mass spectrometry

Mapping of sulfur metabolic pathway by LC Orbitrap mass spectrometry - Rao, Yulan; McCooeye, Margaret; Mester, Zoltán (Analytica Chimica Acta, 2012)
For the first time a liquid chromatography method with high resolution mass spectrometric detection has been developed for the simultaneous determination all key metabolites of the sulfur pathway in yeast, including all thiolic (cysteine (Cys), homocysteine (HCys), glutathione (GSH), cysteinyl-glycine (Cys-Gly), γ-glutamyl-cysteine (Glu-Cys)) and non-thiolic compounds (methionine (Met), s-adenosyl-methionine (AdoMet), s-adenosyl-homocysteine (AdoHcy), and cystathionine (Cysta)). The developed assay also permits the speciation and selective determination of reduced, oxidized and protein bound fractions of all of the five thiols. Iodoacetic acid (IAA) was chosen as the derivatizing reagent. Thiols were extracted from sub-mg quantities of yeast using hot 75% ethanol. The detection limits were in the range of 1–12 nmol L−¹ for standard solution (high femotomole, absolute), except AdoMet (116 nmol L−¹), which was unstable. In freshly harvested yeast, most of the thiols were in the reduced forms and low levels of protein-bound GSH and Glu-Cys were found. In a selenium enriched yeast, the thiols were mainly in the oxidized forms, and a significant amount of protein-bound Cys, HCys, GSH, Cys-Gly and Glu-Cys were found. The method was also applied to the metabolic study of the adaptive response of Saccharomyces cerevisiae to hydrogen peroxide, cadmium, and arsenite, and the change in concentration of thiols in the sulfur pathway was monitored over a period of 4 h.
Keywords: Thiol; Yeast; LTQ-Orbitrap mass spectrometry; Oxidative stress; Metabolic study

Resolution-enhanced native acidic gel electrophoresis: a method for resolving, sizing, and quantifying prion protein oligomers - Ladner, Carol L.; Wishart, David S. (Analytical Biochemistry, 2012)
The formation of β-sheet-rich prion protein (PrPβ) oligomers from native or cellular PrPc is thought to be a key step in the development of prion diseases. To assist in this characterization process we have developed a rapid and remarkably high resolution gel electrophoresis technique called RENAGE (resolution-enhanced native acidic gel electrophoresis) for separating, sizing, and quantifying oligomeric PrPβ complexes. PrPβ oligomers formed via either urea/salt or acid conversion can be resolved by RENAGE into a clear set of oligomeric bands differing by just one subunit. Calibration of the size of the PrPβ oligomer bands was made possible with a cross-linked mouse PrP90–232 ladder (1- to 11-mer) generated using ruthenium bipyridyl-based photoinduced cross-linking of unmodified proteins (PICUP). This PrP PICUP ladder allowed the size and abundance of PrPβ oligomers formed from urea/salt and acid conversion to be determined. This distribution consists of 7-, 8-, 9-, 10-, and 11-mers, with the most abundant species being the 8-mer. The high-resolution separation afforded by RENAGE has allowed us to investigate distinctive size and population changes in PrPβ oligomers formed under various conversion conditions, with various construct lengths, from various species or in the presence of anti-prion compounds.
Keywords: Prion; Electrophoresis; Oligomer; Cross-linking

Bioactive glass 45S5 powders: effect of synthesis route and resultant surface chemistry and crystallinity on protein adsorption from human plasma - Bahniuk, Markian S.; Pirayesh, Hamidreza; Singh, Harsh D.; Nychka, John A.; Unsworth, Larry D. (Biointerphases, 2012)
Despite its medical applications, the mechanisms responsible for the osseointegration of bioactive glass (45S5) have yet to be fully understood. Evidence suggests that the strongest predictor for osseointegration of bioactive glasses, and ceramics, with bone tissue as the formation of an apatitic calcium phosphate layer atop the implanted material, with osteoblasts being the main mediator for new bone formation. Most have tried to understand the formation of this apatitic calcium phosphate layer, and other bioresponses between the host and bioactive glass 45S5 using Simulated Body Fluid; a solution containing ion concentrations similar to that found in human plasma without the presence of proteins. However, it is likely that cell attachment is probably largely mediated via the adsorbed protein layer. Plasma protein adsorption at the tissue bioactive glass interface has been largely overlooked. Herein, we compare crystalline and amorphous bioactive glass 45S5, in both melt-derived as well as sol–gel forms. Thus, allowing for a detailed understanding of both the role of crystallinity and powder morphology on surface ions, and plasma protein adsorption. It was found that sol–gel 45S5 powders, regardless of crystallinity, adsorbed 3–5 times as much protein as the crystalline melt-derived counterpart, as well as a greater variety of plasma proteins. The devitrification of melt-cast 45S5 resulted in only small differences in the amount and variety of the adsorbed proteome. Surface properties, and not material crystallinity, play a role in directing protein adsorption phenomena for bioactive glasses given the differences found between crystalline melt-cast 45S5 and sol–gel derived 45S5.

And mortality in older Chinese adults: results from the Beijing longitudinal study of aging - Fang, X.; Shi, J.; Song, X.; Mitnitski, A.; Tang, Z.; Wang, C.; Yu, P.; Rockwood, Kenneth (The journal of nutrition, health & aging, 2012)
Objectives: Falls are well known to be associated with adverse health outcomes, especially when complicated by fracture. Falls are more common in people who are frail and readily related to several items in the frailty phenotype. Less is known about the relationship between falls and frailty defined as deficit accumulation. Our objective was to investigate the relationship between falls, fractures, and frailty based on deficit accumulation. Design: Representative cohort study, with 8 year follow-up. Setting: The Beijing Longitudinal Study of Aging (BLSA). Participants: 3,257 Chinese people aged 55+ years at baseline. Measurements: A frailty index (FI) was constructed using 33 health deficits, but excluding falls and fractures. The rates of falls, fractures and death as a function of age and the FI were analyzed. Multivariable models evaluated the relationships between frailty and the risk of recurrent falls, fractures, and mortality adjusting for age, sex, and education. Self or informant reported fall and fracture data were verified against participants’ health records. Results: Of 3,257 participants at baseline (1992), 360 people (11.1%) reported a history of falls, and 238 (7.3%) reported fractures. By eight years, 1,155 people had died (35.3%). The FI was associated with an increased risk of recurrent falls (OR=1.54; 95% confidence interval (CI)=1.34–1.76), fractures (OR=1.07; 95% CI=0.94–1.22), and death (OR=1.50, 95% CI=1.41–1.60). The FI showed a significant effect on mortality in a multivariate Cox regression model (Hazard Rate=1.29, 95% CI=1.25–1.33). When adjusted for the FI, neither falls nor fractures were associated with mortality. Conclusion: Falls and fractures were common in older Chinese adults, and associated with frailty. Only frailty was independently associated with death.
Keywords: aging; falls; fractures; frailty index; mortality

Graphene-nickel cobaltite nanocomposite asymmetrical supercapacitor with commercial level mass loading - Wang, Huanlei; Holt, Chris M. B.; Li, Zhi; Tan, Xuehai; Amirkhiz, Babak Shalchi; Xu, Zhanwei; Olsen, Brian C.; Stephenson, Tyler; Mitlin, David (Nano Research, 2012)
A high performance asymmetric electrochemical supercapacitor with a mass loading of 10 mg·cm–² on each planar electrode has been fabricated by using a graphene–nickel cobaltite nanocomposite (GNCC) as a positive electrode and commercial activated carbon (AC) as a negative electrode. Due to the rich number of faradaic reactions on the nickel cobaltite, the GNCC positive electrode shows significantly higher capacitance (618 F·g-¹) than graphene–Co3O4 (340 F∙g-¹) and graphene–NiO (375 F∙g-¹) nanocomposites synthesized under identical conditions. More importantly, graphene greatly enhances the conductivity of nickel cobaltite and allows the positive electrode to charge/discharge at scan rates similar to commercial AC negative electrodes. This improves both the energy density and power density of the asymmetric cell. The asymmetric cell composed of 10 mg GNCC and 30 mg AC displayed an energy density in the range of 19.5 Wh∙kg-¹ with an operational voltage of 1.4 V. At high sweep rate, the system is capable of delivering an energy density of 7.6 Wh∙kg-¹ at a power density of about 5600 W∙kg-¹. Cycling results demonstrate that the capacitance of the cell increases to 116% of the original value after the first 1600 cycles due to a progressive activation of the electrode, and maintains 102% of the initial value after 10000 cycles
Keywords: Graphene; nickel cobaltite (NiCo2O4); supercapacitor; energy density; power density

Scaling of flexural and compressive ice failure - Jordaan, Ian; Taylor, Rocky; Derradji-Aouat, Ahmed (Volume 6 : Materials Technology; Polar and Arctic Sciences and Technology; Petroleum Technology Symposium, 2012)
Physical model tests are a powerful means of obtaining solutions to a variety of engineering problems. The applications in hydraulics and aerospace engineering are prominent, where the use of similitude and dimensionless numbers is well developed. The first step is to understand the mechanics of the process. In the case of ice, the theory has not been developed to the same degree as in fluid mechanics. The use of scale models in test basins has often focused on resistance to ship motion and on flexural failure of the ice. This has been reasonably well addressed. The properties of the model ice have often been modified to permit scaling of flexural strength as well as elastic modulus to achieve appropriate behaviour. Extension of testing to situations where ice fails in compression or combined flexure and crushing leads to additional complication. At low rates of loading, ice creeps and also demonstrates enhanced rates of creep if the stress is sufficient to cause damage (microstructural change) in the ice. At higher rates of loading, fracture processes result in a localization of loading, and in the formation of high-pressure zones, which have their own special failure process. In the paper a review of scaled ice testing is given, with associated mechanics including flexural failure. This is followed by a discussion of the failure processes in compression and related mechanics such as creep, damage and fracture. Suggestions as to scaling of these processes are made. An important aspect that is considered is the randomness of ice loads as measured in the full scale. Modelling this aspect and determination of appropriate extreme values is discussed. The Weibull modulus is suggested as an appropriate parameter.
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Keywords: Ice; Failure

Applicability of non-linear versus linear fractional abundance calibration plots for the quantitative determination of triacylglycerol regioisomers by tandem mass spectrometry - Ramaley, Louis; Cubero Herrera, Lisandra; Melanson, Jeremy E. (Rapid Communications in Mass Spectrometry, 2012)
RATIONALE: Regioisomeric analysis of triacylglycerols is important in understanding lipid biochemistry and the involvement of lipids in disease and nutrition. The use of calibration plots employing fractional abundances provides a simple and rapid method for such analyses. These plots are believed to be linear, but evidence exists for non-linearity. The behavior of such plots needs to be understood to allow for proper interpretation of regioisomeric data. METHODS: Solutions of ﬁve regioisomer pairs were prepared from pure standards and used to construct calibration plots using triple-stage tandem mass spectrometry (MS³) with electrospray ionization (ESIMS³) and cationization by lithium ions. The data were taken by direct infusion with an AB SCIEX QTRAP 2000 QqLIT mass spectrometer. RESULTS: Non-linear calibration plots were observed for the four isomer pairs containing the polyunsaturated eicosapentaenoic (20:5) and docosahexaenoic (22:6) acids paired with palmitic acid (16:0) or myristic acid (14:0), while the pair including palmitic and stearic (18:0) acids provided a linear plot. A non-linear model was developed for these plots and then veriﬁed experimentally. CONCLUSIONS: The fractional abundance calibration plots used in regioisomeric analysis of triacylglycerols are intrinsically non-linear, but may appear linear if the scatter in data points obscures the curvature, if the curvature is slight, or if the response factors for the two isomers in the regioisomer pair are similar. Therefore, linearity should not be assumed for these types of measurements until conﬁrmed experimentally.

Plasma protein profiles of neonatal pigs before and after suckling - Huang, Yanyun; Olson, Douglas J.; Gordon, John R.; Middleton, Dorothy M.; Simko, Elemir (Canadian Journal of Veterinary Research, 2012)
Absorption of colostral proteins ingested by neonatal piglets within 24 to 36 h after birth is generally considered to be nonselective. Nevertheless, the transfer of colostral proteins, except immunoglubulins, from gut to bloodstream after natural suckling is still poorly characterized. The purpose of this study was to investigate the changes in 2-dimensional electrophoretic plasma protein profiles of neonatal piglets before and after suckling, in order to characterize the gastrointestinal absorption of colostral proteins into the neonatal bloodstream. As expected, the most significant change in plasma after suckling is the presence of a large amount of immunoglobulin. However, while the concentration of a few proteins was mildly increased in post-suckling plasma, the evidence of absorption of colostral non-immunoglobulin proteins by neonatal piglets was not detected in this study.

Induction and identification of hexadecaploid of Pinellia ternate - He, LiangYan; Ding, Zhishan; Jiang, Fusheng; Jin, Bo; Li, Weiping; Ding, Xinghong; Sun, Jinyue; Lv, Guiyuan (Euphytica, 2012)
Pinellia ternate (Thunb.) Breit (Araceae) is an important Chinese medicinal herb. In order to obtain the hexadecaploid plants of P. ternate with improved medicinal qualities, the shoot tips from in vitro-grown plants were treated with colchicine at various concentrations for different time to double the chromosome number. We obtained highest (42.5%) frequency of morphological variation when the tips were treated with 0.1% colchicine for 48 h. The putative hexadecaploid plants showed characteristics such as larger and thicker leaves, deeper green leaf color, stouter petiole, larger stomata, lower density of stomata across the lower epidermis of leaves and increased numbers of chloroplasts per stomata guard cell. Further analysis by ﬂow cytometry and chromosome counting conﬁrmed seven out of 129 were hexadecaploids. Besides, the growth rate (GR) of PLBs in hexadecaploid plants was 10.49% (increase rate in 1 day), 1.6 times higher than that of octoploid plants and the alkaloid content of PLBs in hexadecaploid plants was 0.0794%, 1.8 times higher than that of octoploid plant. The results indicated that we have established a successful procedure for development and propagation of hexadecaploid of P. ternate with higher GR and alkaloid content.
Keywords: Alkaloid; Colchicine; Flow cytometry; Hexadecaploid; Morphological characterization; Pinellia ternate

Design and optimization for strength and integrity of tidal turbine rotor blades - Liu, Pengfei; Veitch, Brian (Energy, 2012)
Tidal turbine rotor blade fractures and failures have resulted in substantial damage and hence cost of repair and recovery. The present work presents a rotor blade design and optimization method to address the blade structural strength design problem. The generic procedure is applicable to both turbine rotors and propellers. The optimization method seeks an optimum blade thickness distribution across the span with a prescribed constant safety factor for all the blade sections. This optimization procedure serves two purposes: while maintaining the required structural strength and integrity for an ultimate inflow speed, it aims to reduce the material to a minimum and to maintain power generation efficiency or improve the hydrodynamic efficiency. The value of the chosen minimum safety factor depends on the actual working conditions of the turbine in which the sectional peak loading and frequency are used: the harsher the environment, the larger the required safety factor. An engineering software tool with both hydrodynamic and structural capabilities was required to predict the instantaneous loading acting on all the blade sections, as well as the strength of a local blade section with a given blade geometry and chosen material. A time-domain, 3D unsteady panel method was then implemented based on a marine propeller software tool and used to perform the optimization. A 3-blade 20-m tidal turbine that was prototyped in parallel with the current work for the Bay of Fundy was used as an example for optimization. The optimum thickness distribution for a required safety factor at the ultimate possible inflow speed resulted in 37.6% saving in blade material. The blade thickness and distribution as a function of a maximum inflow speed of 6 m/s is also presented. The blade material used in the example was taken as nickel–aluminium–bronze (NAB) but the procedure was developed to be applicable to propeller or turbine blades of basically any material.
Keywords: Turbine structure; Turbine blade failure; Turbine design optimization; Bay of Fundy; HATT (horizontal axis tidal turbine); Renewable energy

Prototyping a series of bi-directional horizontal axis tidal turbines for optimum energy conversion - Liu, Pengfei; Bose, Neil (Applied Energy, 2012)
A series of bi-directional horizontal axis tidal turbine (HATT) rotors was prototyped. The geometry and motion parameters of the turbine series cover a wide range of tidal turbine operating conditions targeted to the tidal flow speed probability distribution of the Bay of Fundy, NS Canada. A generic yet novel wind/tidal turbine rotor design and optimization procedure was developed and used for the optimization process. In the process, optimum annual energy production, as a benchmark, was obtained and used for comparison by taking into account both rotor hydrodynamic power production performance characteristics and annual tidal inflow speed probability distribution. The diameter of the full-scale bi-directional HATT rotor series developed is 20-m. Optimum values of various variables were obtained for maximum annual energy production. These optimum values include: uniform pitch-diameter-ratio (p/D) distributions, nominal pitch values with different curve forms of non-uniform p/D distributions, shaft rotational speeds under fixed rotor diameter, diameter at fixed tip-speed-ratio (TSR), a combination of optimum shaft speeds at corresponding inflow speeds and optimum uniform p/D distribution at a fixed rotor diameter, number of rotor blades at fixed chord length, rotor solidity at fixed number of blades, and the combination of number of blades and solidity for both optimum constant pitch distribution and optimum linear pitch distribution. For the 20-m bi-directional HATT, a substantial improvement in power coefficient Cpow was obtained, from 0.28, as a result of the primary optimization process (for both optimum uniform p/D distribution and shaft speed n), to the final maximum of 0.43. This corresponds to a 56% increase in annual energy production of 1230 MW h, from 2188 to 3418 MW h, an improved energy production equivalent to the energy generated from 600 tonnes of coal (at 2 kW h per 1 kg coal from a standard thermal power plant). The annual energy production from the optimized 20-m bi-directional HATT before the deduction of mechanical and electrical conversion loses, is 3418 MW h, equivalent to the electric energy generated from 1550 tonnes of coal.
Keywords: Turbine design and optimization; Turbine aerodynamics and hydrodynamics; Bay of Fundy; HATT; Tidal turbine; Tidal power

Remote ice detection equipment — RIDE - Gagnon, R. E.; Groves, J.; Pearson, W. (Cold Regions Science and Technology, 2012)
A new instrument for remote ice detection and thickness measurement is described. It incorporates two optically based technologies that give it capability to measure the thickness of clear or foggy layers of solid or liquid on surfaces. The device is capable of measurements on moving surfaces such as wind turbines, and aircraft propellers and rotors. Details of the prototype are presented along with thickness data acquired during two test programs, one study on clear ice layers where measurements were obtained from a distance of ~ 15 m and the other on foggy ice layers at a distance of approximately 13 m.
Keywords: Remote ice detection; Rime and glaze ice; Icing layer thickness measurement

An explanation for the Molikpaq May 12, 1986 event - Gagnon, R. E. (Cold Regions Science and Technology, 2012)
The ice crushing induced vibration and so-called lock-in behavior exhibited by the Molikpaq structure during a test case event that occurred on May 12, 1986 has been explained in terms of ice spalling, and associated sawtooth load and displacement patterns, and resonance of the coupled structure–ice system where the mass and spring constant associated with the ice sheet are variable ‘effective’ quantities that depend on the ice sheet speed. Spalling at the ice edge contact zone plays a key role since the spalling frequency is directly proportional to the speed of the ice sheet towards the structure. Two modes of spalling are described for this particular event. One mode, called system resonant capped (SRC) spalling, causes loading and displacement that is similar to classic high-amplitude sawtooth loading and displacement and occurs at spalling frequencies in the vicinity of, or less than, the resonant frequency of the structure–ice system. In the present case the SRC spalling appears to be at the system resonant frequency. The other spalling mode is lowdisplacement– amplitude erratic spalling that is characterized by temporal unevenness and unevenness in the magnitude of consecutive displacement sawteeth. This type of spalling occurs at an average spalling frequency of about 4 Hz, which is substantially higher than the SRC spalling frequency range. For the analysis rough estimates for the variation of the effective mass and effective spring constant of the ice sheet throughout a range of spalling frequency were determined numerically. This treatment predicts that, for ice with similar properties as the May 12 event at least, sawtooth loading of the structure that causes structural oscillations is inevitable when an expansive ice sheet crushes against it. Potential means of significantly reducing the amplitude of the load and displacement oscillations by influencing fundamental spalling characteristics using blade-like spall initiators installed on the structure faces at the ice level are discussed.
Keywords: Ice-induced vibration; Lock-in; Ice spalling frequency; Molikpaq structure; Ice spalling modes; Lock-in mitigation

Numerical simulations of a tanker collision with a bergy bit incorporating hydrodynamics, a validated ice model and damage to the vessel - Gagnon, R. E.; Wang, J. (Cold Regions Science and Technology, 2012)
Numerical simulations of a collision between a loaded tanker and a bergy bit have been conducted using LSDyna ™ software. The simulations incorporated hydrodynamics, via LS-Dyna's ALE formulation, and a validated crushable foam ice model. The major portion of the vessel was treated as a rigid body and a section of the hull, located on the starboard side of the forward bow where the ice contact occurred, was modeled as typical ship grillage that could deform and sustain damage as a result of the collision. Strategies for dealing with the highly varying mesh densities needed for the simulations are discussed as well as load and pressure distribution on the grillage throughout the course of the collision. Realistic movement of the bergy bit due to the vessel's bow wave prior to contact with the ice was observed and the damage to the grillage resembled published results from actual grillage damage tests in the lab. A load measurement from the lab tests compared reasonably well with a rough estimate from the simulation. The collision eventually ruptured the hull in a ripping fashion resembling documented incidents of vessel impacts with ice masses.
Keywords: Bergy bit collision; Numerical simulation; Ship damage

An explanation of ice-crushing induced vibrational lock-in using the Molikpaq May 12, 1986 event as a test case - Gagnon, R. E. (Ice Research for a Sustainable Environment, the 21st IAHR International Symposium on Ice, 2012)
The ice crushing induced vibration and so-called lock-in behavior exhibited by the Molikpaq structure during a test case event that occurred on May 12, 1986 has been explained in terms of ice spalling, and associated sawtooth load patterns, and resonance of the coupled structure-ice system where the mass and spring constant associated with the ice sheet are variable ‘effective’ quantities that depend on the ice sheet speed. Spalling at the ice edge contact zone plays a key role since the spalling frequency is directly proportional to the speed of the ice sheet towards the structure. Two modes of spalling are described for this particular event. One mode, called system resonant capped (SRC) spalling, causes loading that is similar to classic high-amplitude sawtooth loading and occurs at spalling frequencies in the vicinity of, or less than, the resonant frequency of the structure-ice system. In the present case the SRC spalling appears to be at the system resonant frequency. The other spalling mode is low-amplitude erratic spalling that is characterized by temporal unevenness and unevenness in the magnitude of consecutive load sawteeth. This type of spalling occurs at an average spalling frequency of about 4 Hz, which is substantially higher than the SRC spalling frequency range. For the analysis rough estimates for the variation of the effective mass and effective spring constant of the ice sheet throughout a range of spalling frequency were determined numerically. This treatment predicts that, for ice with similar properties as the May 12 event at least, sawtooth loading of the structure that cause structural oscillations are inevitable when an expansive ice sheet crushes against it. Potential means of significantly reducing the amplitude of the load oscillations by influencing fundamental spalling characteristics using blade-like spall initiators installed on the structure faces at the ice level are discussed.

Fundamentals of membrane processes - Kumar, Ashwani; Zhang, Tian C.; Surampalli, Roa Y.; Vigneswaran, Saravanamuthu; Tyagi, R. D.; Ong, Say Leong; Kao, C. M. (Membrane Technology and Environmental Applications, 2012)
This chapter describes all important aspects of a membrane-based separation process. After a brief introduction properties of membrane materials and their relevance for gaseous and liquid separation are described in details including the specific information relevant for gas-vapour, reverse osmosis, nanofiltration, ultrafiltration and microfiltration processes. Currently used separation models based on solution diffusion and pore flow are described for different type of membrane processes including the applicable mathematical equations. Use and potential application of Computational Fluid Dynamics techniques in developing improved products and enriching understanding of flow behaviour, has also been included. The Chapter closes with a brief description of future directions in membrane technology and its industrial applications.

Overexpression of AtOGG1, a DNA glycosylase/AP lyase, enhances seed longevity and abiotic stress tolerance in Arabidopsis - Chen, Huhui; Chu, Pu; Zhou, Yuliang; Li, Yin; Liu, Jun; Dung, Yu; Tsang, Edward W. T.; Jiang, Liwen; Wu, Keqiang; Huang, Shangzhi (Journal of Experimental Botany, 2012)
Reactive oxygen species (ROS) are toxic by-products generated continuously during seed desiccation, storage, and germination, resulting in seed deterioration and therefore decreased seed longevity. The toxicity of ROS is due to their indiscriminate reactivity with almost any constituent of the cell, such as lipids, proteins, and DNA. The damage to the genome induced by ROS has been recognized as an important cause of seed deterioration. A prominent DNA lesion induced by ROS is 7,8-dihydro-8-oxoguanine (8-oxo-G), which can form base pairs with adenine instead of cytosine during DNA replication and leads to GC→TA transversions. In Arabidopsis, AtOGG1 is a DNA glycosylase/apurinic/apyrimidinic (AP) lyase that is involved in base excision repair for eliminating 8-oxo-G from DNA. In this study, the functions of AtOGG1 were elaborated. The transcript of AtOGG1 was detected in seeds, and it was strongly up-regulated during seed desiccation and imbibition. Analysis of transformed Arabidopsis protoplasts demonstrated that AtOGG1–yellow fluorescent protein fusion protein localized to the nucleus. Overexpression of AtOGG1 in Arabidopsis enhanced seed resistance to controlled deterioration treatment. In addition, the content of 8-hydroxy-2′-deoxyguanosine (8-oxo-dG) in transgenic seeds was reduced compared to wild-type seeds, indicating a DNA damage-repair function of AtOGG1 in vivo. Furthermore, transgenic seeds exhibited increased germination ability under abiotic stresses such as methyl viologen, NaCl, mannitol, and high temperatures. Taken together, our results demonstrated that overexpression of AtOGG1 in Arabidopsis enhances seed longevity and abiotic stress tolerance.
Keywords: 8-oxo-G; Abiotic stress; AtOGG1; Controlled deterioration treatment; DNA damage and repair; Seed longevity

Peroxisomal Alanine : Glyoxylate Aminotransferase AGT1 is indispensable for appressorium function of the rice blast pathogen, Magnaporthe oryzae - Bhadauria, Vijai; Banniza, Sabine; Vandenberg, Albert; Selvaraj, Gopalan; Wei, Yangdou (PLoS ONE, 2012)
The role of β-oxidation and the glyoxylate cycle in fungal pathogenesis is well documented. However, an ambiguity still remains over their interaction in peroxisomes to facilitate fungal pathogenicity and virulence. In this report, we characterize a gene encoding an alanine, glyoxylate aminotransferase 1 (AGT1) in Magnaporthe oryzae, the causative agent of rice blast disease, and demonstrate that AGT1 is required for pathogenicity of M. oryzae. Targeted deletion of AGT1 resulted in the failure of penetration via appressoria; therefore, mutants lacking the gene were unable to induce blast symptoms on the hosts rice and barley. This penetration failure may be associated with a disruption in lipid mobilization during conidial germination as turgor generation in the appressorium requires mobilization of lipid reserves from the conidium. Analysis of enhanced green fluorescent protein expression using the transcriptional and translational fusion with the AGT1 promoter and open reading frame, respectively, revealed that AGT1 expressed constitutively in all in vitro grown cell types and during in planta colonization, and localized in peroxisomes. Peroxisomal localization was further confirmed by colocalization with red fluorescent protein fused with the peroxisomal targeting signal 1. Surprisingly, conidia produced by the Δagt1 mutant were unable to form appressoria on artificial inductive surfaces, even after prolonged incubation. When supplemented with nicotinamide adenine dinucleotide (NAD+)+pyruvate, appressorium formation was restored on an artificial inductive surface. Taken together, our data indicate that AGT1-dependent pyruvate formation by transferring an amino group of alanine to glyoxylate, an intermediate of the glyoxylate cycle is required for lipid mobilization and utilization. This pyruvate can be converted to non-fermentable carbon sources, which may require reoxidation of NADH generated by the β-oxidation of fatty acids to NAD+ in peroxisomes. Therefore, it may provide a means to maintain redox homeostasis in appressoria.
Keywords: Gene Expression Regulation, Fungal; Glyoxylates; Hordeum; Magnaporthe; NAD; Oryza sativa; Oxidation-Reduction; Peroxisomes; Plant Diseases; Protein Transport; Pyruvic Acid; Sequence Deletion; Surface Properties; Transaminases

Fatty acid composition of developing sea buckthorn (Hippophae rhamnoides L.) Berry and the Transcriptome of the mature seed - Fatima, Tahira; Snyder, Crystal L.; Schroeder, William R.; Cram, Dustin; Datla, Raju; Wishart, David; Weselake, Randall J.; Krishna, Priti (PLoS ONE, 2012)
Background: Sea buckthorn (Hippophae rhamnoides L.) is a hardy, fruit-producing plant known historically for its medicinal and nutraceutical properties. The most recognized product of sea buckthorn is its fruit oil, composed of seed oil that is rich in essential fatty acids, linoleic (18:2ω-6) and α-linolenic (18:3ω-3) acids, and pulp oil that contains high levels of monounsaturated palmitoleic acid (16:1ω-7). Sea buckthorn is fast gaining popularity as a source of functional food and nutraceuticals, but currently has few genomic resources; therefore, we explored the fatty acid composition of Canadian-grown cultivars (ssp. mongolica) and the sea buckthorn seed transcriptome using the 454 GS FLX sequencing technology. Results: GC-MS profiling of fatty acids in seeds and pulp of berries indicated that the seed oil contained linoleic and α-linolenic acids at 33-36% and 30-36%, respectively, while the pulp oil contained palmitoleic acid at 32-42%. 454 sequencing of sea buckthorn cDNA collections from mature seeds yielded 500,392 sequence reads, which identified 89,141 putative unigenes represented by 37,482 contigs and 51,659 singletons. Functional annotation by Gene Ontology and computational prediction of metabolic pathways indicated that primary metabolism (protein>nucleic acid>carbohydrate>lipid) and fatty acid and lipid biosynthesis pathways were highly represented categories. Sea buckthorn sequences related to fatty acid biosynthesis genes in Arabidopsis were identified, and a subset of these was examined for transcript expression at four developing stages of the berry. Conclusion: This study provides the first comprehensive genomic resources represented by expressed sequences for sea buckthorn, and demonstrates that the seed oil of Canadian-grown sea buckthorn cultivars contains high levels of linoleic acid and α-linolenic acid in a close to 1:1 ratio, which is beneficial for human health. These data provide the foundation for further studies on sea buckthorn oil, the enzymes involved in its biosynthesis, and the genes involved in the general hardiness of sea buckthorn against environmental conditions.
Keywords: alpha-Linolenic Acid; Base Sequence; Biosynthetic Pathways; Fatty Acids; Fatty Acids, Monounsaturated; Fruit; Gas Chromatography-Mass Spectrometry; Gene Expression Profiling; Gene Library; Hippophae; Linoleic Acid; Molecular Sequence Data; Plant Oils; RNA-Directed DNA Polymerase; Saskatchewan; Seeds; Sequence Analysis, DNA; Transcriptome

Developments in signal processing and interpretation in laser tapping - Perton, M.; Neron, C.; Blouin, A.; Monchalin, J.-P. (Review Of Progress In Quantitative Nondestructive Evaluation, 2012)
A novel technique, called laser-tapping, based on the thermoelastic excitation by laser like laser-ultrasonics has been previously introduced for inspecting honeycomb and foam core structures. If the top skin is delaminated or detached from the substrate, the detached layer is driven into vibration. The interpretation of the vibrations in terms of Lamb wave resonances is first discussed for a flat bottom hole configuration and then used to determine appropriate signal processing for samples such as honeycomb structures.
Keywords: Laser-ultrasound; Laser tapping; Tapping; Disbond; Honeycomb structures

In vitro cytotoxicity and genotoxicity studies of titanium dioxide (TiO2) nanoparticles in Chinese hamster lung fibroblast cells - Hamzeh, Mahsa; Sunahara, Geoffrey I. (Toxicology in Vitro, 2012)
There are increasing safety concerns about the development and abundant use of nanoparticles. The unique physical and chemical characteristics of titanium dioxide (TiO2) nanoparticles result in different chemical and biological activities compared to their larger micron-sized counterparts, and can subsequently play an important role in influencing toxicity. Therefore, our objective was to investigate the cytotoxicity and genotoxicity of commercially available TiO2 nanoparticles with respect to their selected physicochemical properties, as well as the role of surface coating of these nanoparticles. While all types of tested TiO2 samples decrease cell viability in a mass-based concentration- and size-dependent manner, the polyacrylate-coated nano-TiO2 product was only cytotoxic at higher concentrations. A similar pattern of response was observed for induction of apoptosis/necrosis, and no DNA damage was detected in the polyacrylate-coated nano-TiO2 model. Given the increasing production of TiO2 nanoparticles, toxicological studies should take into account the physiochemical properties of these nanoparticles that may help researchers to develop new nanoparticles with minimum toxicity.
Keywords: Nanotoxicology; Surface modification; Cell death; Oxidative stress; DNA damage; Comet assay; Flow cytometry

Intravascular optical coherence tomography to characterize tissue deformation during angioplasty : preliminary experiments with artery phantoms - Azarnoush, Hamed; Vergnole, Sébastien; Pazos, Valérie; Bisaillon, Charles-Étienne; Boulet, Benoit; Lamouche, Guy (Journal of Biomedical Optics, 2012)
We explored the potential of intravascular optical coherence tomography (IVOCT) to assess deformation during angioplasty balloon inflation. Using a semi-compliant balloon and artery phantoms, we considered two experimental scenarios. The goal for the first scenario was to investigate if variation in the elasticity of the structure surrounding the balloon could be sensed by IVOCT monitoring. In this scenario, we used three single-layer phantoms with various mechanical properties. Image analysis was performed to extract the inner and outer diameters of the phantoms at various pressures. The goal for the second scenario was twofold. First, we investigated the IVOCT capability to monitor a more complex balloon inflation process. The balloon was in a folded state prior to inflation. This allowed studying two stages of deformation: during balloon unfolding and during balloon expansion. Second, we investigated IVOCT capability to monitor the deformation in a three-layer phantom used to better mimic a true artery. So, not only were the IVOCT images processed to provide the inner and outer diameters of the phantom, but the layer thicknesses were also determined. In both scenarios, IVOCT monitoring revealed to be very efficient in providing relevant information about the phantom deformation during balloon inflation.
Keywords: Angioplasty; Optical coherence tomography; Tissue characterization

Improved isolation procedure for azaspiracids from shellfish, structural elucidation of azaspiracid-6, and stability studies - Kilcoyne, Jane; Keogh, Adela; Clancy, Ger; LeBlanc, Patricia; Burton, Ian; Quilliam, Michael A.; Hess, Philipp; Miles, Christopher O. (Journal of Agricultural and Food Chemistry, 2012)
Azaspiracids are a group of lipophilic polyether toxins produced by the small dinoflagellate Azadinium spinosum. They may accumulate in shellfish and can result in illnesses when consumed by humans. Research into analytical methods, chemistry, metabolism, and toxicology of azaspiracids has been severely constrained by the scarcity of high-purity azaspiracids. Consequently, since their discovery in 1995, considerable efforts have been made to develop methods for the isolation of azaspiracids in sufficient amounts and purities for toxicological studies, in addition to the preparation of standard reference materials. A seven-step procedure was improved for the isolation of azaspiracids-1–3 (1, 2, and 3) increasing recoveries 2-fold as compared to previous methods and leading to isolation of sufficiently purified azaspiracid-6 (6) for structural determination by NMR spectroscopy. The procedure, which involved a series of partitioning and column chromatography steps, was performed on 500 g of Mytilus edulis hepatopancreas tissue containing 14 mg of 1. Overall yields of 1 (52%), 2 (43%), 3 (43%), and 6 (38%) were good, and purities were confirmed by NMR spectroscopy. The structure of 6 was determined by one- and two-dimensional NMR spectroscopy and mass spectrometry. The stability of 6 relative to 1 was also assessed in three solvents in a short-term study that demonstrated the greatest stability in aqueous acetonitrile.
Keywords: acid; stability; NMR; mass spectrometry; purification

Transcriptome profiling and methyl homeostasis of an Arabidopsis mutant deficient in S-adenosylhomocysteine hydrolase1 (SAHH1) - Ouyang, Bo; Fei, Zhangjun; Joung, Je-Gun; Kolenovsky, Allan; Koh, Chushin; Nowak, Jacek; Caplan, Allan; Keller, Wilfred A.; Cui, Yuhai; Cutler, Adrian J.; Tsang, Edward W. T. (Plant Molecular Biology, 2012)
Transcriptome profiling was conducted to detect genes whose expression is significantly changed in an Arabidopsis mutant deficient in S-adenosylhomocysteine hydrolase1 (SAHH1) during early seedling development when mutant phenotypes could be clearly observed. A total of 2,040 differentially expressed genes were identified, representing approximately 6.7 % of the 30,385 DNA oligonucleotide targets on the microarray. Among these differential expressed genes, many were mapped to pathways essential to plant growth and development including those of primary, secondary and hormone metabolisms. A significant proportion of up-regulated genes encoded transposable elements which were mapped to the centromeric and pericentromeric regions of the Arabidopsis chromosomes that were analyzed. A number of down-regulated genes were found to be involved in root hair formation, which might have contributed to the root hair defective phenotype of the mutant. Analysis of genes encoding transposable elements and those associating with root hair development indicated that these genes were highly co-expressed during seedling development. Despite SAHH1 deficiency, the expression of genes encoding methyltransferase remained largely unchanged in the sahh1 mutant. Bisulfite sequencing analysis of the transposable elements and the FWA gene revealed that their sequences in the mutant were deficient of 5-methylcytosines. Analysis of mutant genomic DNA using restriction endonucleases that were unable to cut methylated DNA suggested a genome-wide hypomethylation had occurred in the mutant. These results indicated that SAHH1 plays a critical role in methyl homeostasis, and its deficiency is a major contributing factor to the change of global gene expression, metabolic pathways and activation of transposable elements in the sahh1 mutant.
Keywords: Seedling development; microarray; S-adenosylethionine; methyltransferase; Methyl homeostasis; transposons; root hair

Identification of olivetolic acid cyclase from Cannabis sativa reveals a unique catalytic route to plant polyketides - Gagne, Steve J.; Stout, Jake M.; Liu, Enwu; Boubakir, Zakia; Clark, Shawn M.; Page, Jonathan E. (Proceedings of the National Academy of Sciences of the United States of America, 2012)
Δ9-Tetrahydrocannabinol (THC) and other cannabinoids are responsible for the psychoactive and medicinal properties of Cannabis sativa L. (marijuana). The first intermediate in the cannabinoid biosynthetic pathway is proposed to be olivetolic acid (OA), an alkylresorcinolic acid that forms the polyketide nucleus of the cannabinoids. OA has been postulated to be synthesized by a type III polyketide synthase (PKS) enzyme, but so far type III PKSs from cannabis have been shown to produce catalytic byproducts instead of OA. We analyzed the transcriptome of glandular trichomes from female cannabis flowers, which are the primary site of cannabinoid biosynthesis, and searched for polyketide cyclase-like enzymes that could assist in OA cyclization. Here, we show that a type III PKS (tetraketide synthase) from cannabis trichomes requires the presence of a polyketide cyclase enzyme, olivetolic acid cyclase (OAC), which catalyzes a C2–C7 intramolecular aldol condensation with carboxylate retention to form OA. OAC is a dimeric α+β barrel (DABB) protein that is structurally similar to polyketide cyclases from Streptomyces species. OAC transcript is present at high levels in glandular trichomes, an expression profile that parallels other cannabinoid pathway enzymes. Our identification of OAC both clarifies the cannabinoid pathway and demonstrates unexpected evolutionary parallels between polyketide biosynthesis in plants and bacteria. In addition, the widespread occurrence of DABB proteins in plants suggests that polyketide cyclases may play an overlooked role in generating plant chemical diversity.
Keywords: Natural products; phytocannabinoid; terpenophenolic; aldolase; ferredoxin-like

Alanine : Glyoxylate aminotransferase 1 is required for mobilization and utilization of triglycerides during infection process of the rice blast pathogen, Magnaporthe oryzae - Bhadauria, Vijai; Banniza, Sabine; Vandenberg, Albert; Selvaraj, Gopalan; Wei, Yangdou (Plant Signaling & Behavior, 2012)
The rice blast pathogen, Magnaporthe oryzae has been widely used as a model pathogen to study plant infection-related fungal morphogenesis, such as penetration via appressorium and plant-microbe interactions at the molecular level. Previously, we identified a gene encoding peroxisomal alanine: glyoxylate aminotransferase 1 (AGT1) in M. oryzae and demonstrated that the AGT1 was indispensable for pathogenicity. The AGT1 knockout mutants were unable to penetrate the host plants, such as rice and barley, and therefore were non-pathogenic. The inability of ∆Moagt1 mutants to penetrate the susceptible plants was likely due to the disruption in coordination of the β-oxidation and the glyoxylate cycle resulted from a blockage in lipid droplet mobilization and eventually utilization during conidial germination and appressorium morphogenesis, respectively. Here, we further demonstrate the role of AGT1 in lipid mobilization by in vitro germination assays and confocal microscopy.
Keywords: Pathogenicity; conidia; appressorium; lipid; AGT1

Doubled haploidy as a tool in ornamental breeding - Ferrie, A. M. R. (XXIV International Eucarpia Symposium Section Ornamentals: Ornamental Breeding Worldwide, 2012)
Haploidy/doubled haploidy methodology is commonly used in many agronomically important crops to speed the development of new cultivars. There are a number of advantages in using haploidy technology in both practical application (varietal development, mutagenesis, transformation) and basic research (genomics, biochemical, and physiological studies). Haploid plants are commonly produced using one of four methods: culture of anthers or microspores (androgenesis), culture of unfertilized ovules (gynogenesis), interspecific or intergeneric crosses followed by chromosome elimination, and by pollination with irradiated pollen. The most efficient method depends on the species. In many species, the culture of isolated microspores or anthers is the most frequently used method of haploid production. With this method, every microspore is potentially capable of regenerating into a viable embryo and each plant would therefore represent the variation which exists in the population of microspores. Plant regeneration occurs either by direct embryogenesis or through callus formation followed by embryogenesis or organogenesis. There are a number of factors influencing embryogenesis from anther/microspores or ovaries/ovules including genotype, donor plant growth conditions, stage of explant development, composition of the culture medium, and environmental conditions during culture. The frequency of embryo production will depend on whether or not these conditions are optimal and varies depending on the species. Compared to some agronomic species, there has been very little work on doubled haploidy in ornamental species despite the potential benefits.
Keywords: Androgenesis; gynogenesis; microspore embryogenesis

Identification and quantification of Cyclolinopeptides in five flaxseed cultivars - Gui, Bo; Shim, Youn Young; Datla, Raju S. S.; Covello, Patrick S.; Stone, Sandra L.; Reaney, Martin J. T. (Journal of Agricultural and Food Chemistry, 2012)
Cyclolinopeptides are a group of naturally occurring hydrophobic cyclic peptides found in flaxseed and flax oil that have immunosuppressive activity. This study describes the measurement of flaxseed cyclolinopeptide concentrations using an internal standard HPLC method. In addition, the concentration of cyclolinopeptides in the seed of Canadian flax cultivars grown at two locations over two years is reported. The data are consistent with the formation of flaxseed cyclolinopeptides from two ribosome-derived precursors. Each precursor protein includes the sequences corresponding to three cyclolinopeptides from which those cyclolinopeptides are presumably derived by precursor processing. The concentrations of cyclolinopeptides C and E, which are encoded by the same gene sequence, are highly correlated, and the concentrations of cyclolinopeptides D, F, and G, which are encoded by a second gene sequence, are also highly correlated. The strong correlation between the cyclolinopeptides arising from the same gene may prove to be important in understanding how peptide concentration is controlled. Additional research may lead to approaches to improve flax either as a platform for peptide production or as a source of oil with improved drying properties and flavor.
Keywords: cyclolinopeptide; HPLC quantification; flaxseed cultivars; environment interaction

Arabidopsis mutant sk156 reveals complex regulation of SPL15 in a miR156-controlled gene network - Wei, Shu; Gruber, Margaret Y.; Yu, Bianyun; Gao, Ming-Jun; Khachatourians, George G.; Hegedus, Dwayne D.; Parkin, Isobel A. P.; Hannoufa, Abdelali (BMC Plant Biology, 2012)
Background: The Arabidopsis microRNA156 (miR156) regulates 11 members of the SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL) family by base pairing to complementary target mRNAs. Each SPL gene further regulates a set of other genes; thus, miR156 controls numerous genes through a complex gene regulation network. Increased axillary branching occurs in transgenic Arabidopsis overexpressing miR156b, similar to that observed in loss-of-function max3 and max4 mutants with lesions in carotenoid cleavage dioxygenases. Arabidopsis miR156b was found to enhance carotenoid levels and reproductive shoot branching when expressed in Brassica napus, suggesting a link between miR156b expression and carotenoid metabolism. However, details of the miR156 regulatory network of SPL genes related to carotenoid metabolism are not known. Results: In this study, an Arabidopsis T-DNA enhancer mutant, sk156, was identified due to its altered branching and trichome morphology and increased seed carotenoid levels compared to wild type (WT) ecovar Columbia. Enhanced miR156b expression due to the 35S enhancers present on the T-DNA insert was responsible for these phenotypes. Constitutive and leaf primodium-specific expression of a miR156-insensitive (mutated) SPL15 (SPL15m) largely restored WT seed carotenoid levels and plant morphology when expressed in sk156. The Arabidopsis native miR156-sensitive SPL15 (SPL15n) and SPL15m driven by a native SPL15 promoter did not restore the WT phenotype in sk156. Our findings suggest that SPL15 function is somewhat redundant with other SPL family members, which collectively affect plant phenotypes. Moreover, substantially decreased miR156b transcript levels in sk156 expressing SPL15m, together with the presence of multiple repeats of SPL-binding GTAC core sequence close to the miR156b transcription start site, suggested feedback regulation of miR156b expression by SPL15. This was supported by the demonstration of specific in vitro interaction between DNA-binding SBP domain of SPL15 and the proximal promoter sequence of miR156b. Conclusions: Enhanced miR156b expression in sk156 leads to the mutant phenotype including carotenoid levels in the seed through suppression of SPL15 and other SPL target genes. Moreover, SPL15 has a regulatory role not only for downstream components, but also for its own upstream regulator miR156b.
Keywords: Arabidopsis; Brassica napus

MicroRNA–mediated repression of the seed maturation program during vegetative development in Arabidopsis - Tang, Xurong; Bian, Shaomin; Tang, Mingjuan; Lu, Qing; Li, Shengben; Liu, Xigang; Tian, Gang; Nguyen, Vi; Tsang, Edward W. T.; Wang, Aiming; Rothstein, Steven J.; Chen, Xuemei; et al. (PLoS Genetics, 2012)
The seed maturation program only occurs during late embryogenesis, and repression of the program is pivotal for seedling development. However, the mechanism through which this repression is achieved in vegetative tissues is poorly understood. Here we report a microRNA (miRNA)–mediated repression mechanism operating in leaves. To understand the repression of the embryonic program in seedlings, we have conducted a genetic screen using a seed maturation gene reporter transgenic line in Arabidopsis (Arabidopsis thaliana) for the isolation of mutants that ectopically express seed maturation genes in leaves. One of the mutants identified from the screen is a weak allele of ARGONAUTE1 (AGO1) that encodes an effector protein for small RNAs. We first show that it is the defect in the accumulation of miRNAs rather than other small RNAs that causes the ectopic seed gene expression in ago1. We then demonstrate that overexpression of miR166 suppresses the derepression of the seed gene reporter in ago1 and that, conversely, the specific loss of miR166 causes ectopic expression of seed maturation genes. Further, we show that ectopic expression of miR166 targets, type III homeodomain-leucine zipper (HD-ZIPIII) genes PHABULOSA (PHB) and PHAVOLUTA (PHV), is sufficient to activate seed maturation genes in vegetative tissues. Lastly, we show that PHB binds the promoter of LEAFY COTYLEDON2 (LEC2), which encodes a master regulator of seed maturation. Therefore, this study establishes a core module composed of a miRNA, its target genes (PHB and PHV), and the direct target of PHB (LEC2) as an underlying mechanism that keeps the seed maturation program off during vegetative development.
Keywords: allele; Arabidopsis; argonaute 1 gene; article; bioaccumulation; controlled study; gene function; gene interaction; gene isolation; gene loss; gene overexpression; gene repression; genetic code; genetic screening; PHABULOSA gene; PHAVOLUTA gene; plant gene; plant leaf; reporter gene; seed development; transgenic plant; vegetative growth; argonaute 1 protein; microRNA; microRNA 166; small untranslated RNA; unclassified drug

Genome-wide comparative analysis of Annexin superfamily in plants - Jami, Sravan Kumar; Clark, Greg B.; Ayele, Belay T.; Ashe, Paula; Kirti, Pulugurtha Bharadwaja (PLoS ONE, 2012)
Most annexins are calcium-dependent, phospholipid-binding proteins with suggested functions in response to environmental stresses and signaling during plant growth and development. They have previously been identified and characterized in Arabidopsis and rice, and constitute a multigene family in plants. In this study, we performed a comparative analysis of annexin gene families in the sequenced genomes of Viridiplantae ranging from unicellular green algae to multicellular plants, and identified 149 genes. Phylogenetic studies of these deduced annexins classified them into nine different arbitrary groups. The occurrence and distribution of bona fide type II calcium binding sites within the four annexin domains were found to be different in each of these groups. Analysis of chromosomal distribution of annexin genes in rice, Arabidopsis and poplar revealed their localization on various chromosomes with some members also found on duplicated chromosomal segments leading to gene family expansion. Analysis of gene structure suggests sequential or differential loss of introns during the evolution of land plant annexin genes. Intron positions and phases are well conserved in annexin genes from representative genomes ranging from Physcomitrella to higher plants. The occurrence of alternative motifs such as K/R/HGD was found to be overlapping or at the mutated regions of the type II calcium binding sites indicating potential functional divergence in certain plant annexins. This study provides a basis for further functional analysis and characterization of annexin multigene families in the plant lineage.
Keywords: annexin gene; Arabidopsis; article; binding site; calcium binding; comparative study; gene duplication; gene identification; gene location; gene loss; gene sequence; genetic association; genetic variability; green alga; intron; molecular phylogeny; nonhuman; phylogenetic tree; plant evolution; plant gene; plant genome; protein domain; rice; structure analysis

Maple sap and syrup are a rich source of abscisic acid with potential benefits to health - Desjardins, Y.; Ratti, C.; Zaharia, I.; Abrams, S. (XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Emerging Health Topics in Fruits and Vegetables, 2012)
For centuries maple sap and syrup have been a staple of North-American native people and are consumed now-a-days throughout the world as edulcoration produce and natural sweeteners. Apart from sugar, the natural sap contains minerals, oligosaccharides, some proteins, polyphenols and phytohormones. The sap and processed syrup are rich in abscisic acid (ABA) and its oxidation metabolites phaseic acid and dihydrophaseic acid depicting a strong oxidative inactivation of ABA prior to bud break. Actually, phaseic acid and dihydrophaseic acid account for almost 90% of this class of molecules, while ABA account for less to 10% of this sesquiterpenoid in the sap and syrup. The high titer of ABA and ABA metabolites may be associated to reduction in chronic diseases.
Keywords: Acer saccharum; sugar maple; phytohormones; sap; syrup; diabetes; HPLC-MS

Gene expression analysis in microdissected shoot meristems of Brassica napus microspore-derived embryos with altered SHOOTMERISTEMLESS levels - Elhiti, Mohamed; Wally, Owen S. D.; Belmonte, Mark F.; Chan, Ainsley; Cao, Yongguo; Xiang, Daoquan; Datla, Raju; Stasolla, Claudio (Planta, 2012)
Altered expression of Brassica napus (Bn) SHOOTMERISTEMLESS (STM) affects the morphology and behaviour of microspore-derived embryos (MDEs). While down-regulation of BnSTM repressed the formation of the shoot meristem (SAM) and reduced the number of Brassica MDEs able to regenerate viable plants at germination, over-expression of BnSTM enhanced the structure of the SAM and improved regeneration frequency. Within dissected SAMs, the induction of BnSTM up-regulated the expression of many transcription factors (TFs) some of which directly involved in the formation of the meristem, i.e. CUP-SHAPED COTYLEDON1 and WUSCHEL, and regulatory components of the antioxidant response, hormone signalling, and cell wall synthesis and modiﬁcation. Opposite expression patterns for some of these genes were observed in the SAMs of MDEs down-regulating BnSTM. Altered expression of BnSTM affected transcription of cell wall and lignin biosynthetic genes. The expression of PHENYLALANINE AMMONIA LYASE2, CINNAMATE 4-4HYDROXYLASE, and CINNAMYL ALCOHOL DEHYDROGENASE were repressed in SAMs over-expressing BnSTM. Since lignin formation is a feature of irreversible cell differentiation, these results suggest that one way in which BnSTM promotes indeterminate cell fate may be by preventing the expression of components of biochemical pathways involved in the accumulation of lignin in the meristematic cells. Overall, these studies provide evidence for a novel function of BnSTM in enhancing the quality of in vitro produced meristems, and propose that this gene can be used as a potential target to improve regeneration of cultured embryos.
Keywords: Brassica; gene expression; microarray; microspore-derived embryos; shoot apical meristem

Overexpression of a novel biotrophy-specific colletotrichum truncatum Effector, CtNUDIX, in hemibiotrophic fungal phytopathogens causes incompatibility with their host plants - Bhadauria, Vijai; Banniza, Sabine; Vandenberg, Albert; Selvaraj, Gopalan; Wei, Yangdou (Eukaryotic Cell, 2012)
The hemibiotrophic fungus Colletotrichum truncatum causes anthracnose disease on lentils and a few other grain legumes. It shows initial symptomless intracellular growth, where colonized host cells remain viable (biotrophy), and then switches to necrotrophic growth, killing the colonized host plant tissues. Here, we report a novel effector gene, CtNUDIX, from C. truncatum that is exclusively expressed during the late biotrophic phase (before the switch to necrotrophy) and elicits a hypersensitive response (HR)-like cell death in tobacco leaves transiently expressing the effector. CtNUDIX homologs, which contain a signal peptide and a Nudix hydrolase domain, may be unique to hemibiotrophic fungal and fungus-like plant pathogens. CtNUDIX lacking a signal peptide or a Nudix motif failed to induce cell death in tobacco. Expression of CtNUDIX:eGFP in tobacco suggested that the fusion protein might act on the host cell plasma membrane. Overexpression of CtNUDIX in C. truncatum and the rice blast pathogen, Magnaporthe oryzae, resulted in incompatibility with the hosts lentil and barley, respectively, by causing an HR-like response in infected host cells associated with the biotrophic invasive hyphae. These results suggest that C. truncatum and possibly M. oryzae elicit cell death to signal the transition from biotrophy to necrotrophy.

The multigene family of lysophosphatidate acyltransferase (LPAT)-related enzymes in Ricinus communis. Cloning and molecular characterization of two LPAT genes that are expressed in castor seeds - Arroyo-Caro, José María; Chileh, Tarik; Kazachkov, Michael; Zou, Jitao; Alonso, Diego López; García-Maroto, Federico (Plant Science, 2012)
The multigene family encoding proteins related to lysophosphatidyl-acyltransferases (LPATs) has been analyzed in the castor plant Ricinus communis. Among them, two genes designated RcLPAT2 and RcLPATB, encoding proteins with LPAT activity and expressed in the developing seed, have been cloned and characterized in some detail. RcLPAT2 groups with well characterized members of the so-called A-class LPATs and it shows a generalized expression pattern in the plant and along seed development. Enzymatic assays of RcLPAT2 indicate a preference for ricinoleoyl-CoA over other fatty acid thioesters when ricinoleoyl-LPA is used as the acyl acceptor, while oleoyl-CoA is the preferred substrate when oleoyl-LPA is employed. RcLPATB groups with B-class LPAT enzymes described as seed speciﬁc and selective for unusual fatty acids. However, RcLPATB exhibit a broad speciﬁcity on the acyl-CoAs, with saturated fatty acids (12:0–16:0) being the preferred substrates. RcLPATB is upregulated coinciding with seed triacylglycerol accumulation, but its expression is not restricted to the seed. These results are discussed in the light of a possible role for LPAT isoenzymes in the channelling of ricinoleic acid into castor bean triacylglycerol.
Keywords: Ricinus communis; castor plant; lipid biosythesis; phosphatidic acid; lysophosphatidate acyltransferase; LPAT

Stable and recyclable Au25 clusters for the reduction of 4-nitrophenol - Shivhare, Atal; Ambrose, Stephen J.; Zhang, Haixia; Purves, Randy W.; Scott, Robert W. J. (Chemical Communications, 2012)
Thiol-stabilized Au₂₅L₁₈ monolayer protected clusters (MPCs) were found to be active for the reduction of 4-nitrophenol. Results suggest that these MPCs are stable catalysts and do not lose their structural integrity during the catalytic process. High stability under the reaction conditions enables the recyclability of these MPCs.
Keywords: 4 nitrophenol; gold; thiol derivative; article; catalyst; chemical reaction; reaction analysis; reduction; structure analysis

Involvement of Arabidopsis acyl-coenzyme A desaturase-like2 (At2g31360) in the biosynthesis of the very-long-chain monounsaturated fatty acid components of membrane lipids - Smith, Mark A.; Dauk, Melanie; Ramadan, Hussein; Yang, Hui; Seamons, Laura E.; Haslam, Richard P.; Beaudoin, Frédéric; Ramirez-Erosa, Irving; Forseille, Li (Plant Physiology, 2012)
The Arabidopsis (Arabidopsis thaliana) acyl-coenzyme A (CoA) desaturase-like (ADS) gene family contains nine genes encoding fatty acid desaturase-like proteins. The biological function of only one member of the family, fatty acid desaturase5 (AtADS3/ FAD5, At3g15850), is known, and this gene encodes the plastidic palmitoyl-monogalactosyldiacylglycerol D7 desaturase. We cloned seven members of the gene family that are predicted not to have a chloroplast transit peptide and expressed them in the yeast Saccharomyces cerevisiae. All seven have previously undescribed desaturase activity on very-long-chain fatty acid (VLCFA) substrates and exhibit diverse regiospeciﬁcity, catalyzing introduction of double bonds relative to the methyl end of the molecule (n-x) at n-6 (AtADS4, At1g06350), n-7 (AtADS1.3, At1g06100 and AtADS4.2, At1g06360), n-9 (AtADS1, At1g06080 and AtADS2, At2g31360) or D9 (relative to the carboxyl end of the molecule) positions (AtADS1.2, At1g06090 and AtADS1.4, At1g06120). Through forward and reverse genetics it was shown that AtADS2 is involved in the synthesis of the 24:1(n-9) and 26:1(n-9) components (X:Y, where X is chain length and Y is number of double bonds) of seed lipids, sphingolipids, and the membrane phospholipids phosphatidylserine, and phosphatidylethanolamine. Plants deﬁcient in AtADS2 expression showed no obvious phenotype when grown under normal growing conditions, but showed an almost complete loss of phosphatidylethanolamine (42:4), phosphatidylserine(42:4), dihydroxy-monohexosylceramide(42:2)-2, trihydroxy-monohexosylceramide(42:2)-3, and trihydroxy-glycosylinositolphosphoceramide(42:2)-3, lipid species that contain the VLCFA 24:1(n-9), and trihydroxyglycosylinositolphosphoceramide(44:2)-3, a lipid containing 26:1(n-9). Acyl-CoA proﬁling of these plants revealed a major reduction in 24:1-CoA and a small reduction in 26:1-CoA. Overexpression of AtADS2 resulted in a substantial increase in the percentage of glycerolipid and sphingolipids species containing 24:1 and a dramatic increase in the percentage of very-long-chain monounsaturated fatty acids in the acyl-CoA pool. Plants deﬁcient in AtADS1 expression had reduced levels of 26:1(n-9) in seed lipids, but no signiﬁcant changes in leaf phospholipids or sphingolipids were observed. These ﬁndings indicate that the 24-carbon and 26-carbon monounsaturated VLCFAs of Arabidopsis result primarily from VLCFA desaturation, rather than by elongation of long chain monounsaturated fatty acids.

Differential metabolite profiles and salinity tolerance between two genetically related brown-seeded and yellow-seeded Brassica carinata lines - Canam, Thomas; Li, Xiang; Holowachuk, Jennifer; Yu, Min; Xia, Jianguo; Mandal, Rupasri; Krishnamurthy, Ramanarayan; Bouatra, Souhaila; Sinelnikov, Igor; Yu, Bianyun; Grenkow, Larry; Wishart, David S.; et al. (Plant Science, 2012)
Brassica carinata (Ethiopian mustard) has previously been identiﬁed as a potential crop species suitable for marginal land in the North American prairies due to its relatively high salt tolerance. Two genetically related B. carinata lines with brown-seeded (BS) and yellow-seeded (YS) phenotypes were assessed for their tolerance to sodium sulfate. Speciﬁcally, each line was greenhouse-grown under 0, 50 and 100 mM of salt, and analyzed after four weeks and eight weeks of treatment. Generally, the height of the BS line was greater than the YS line under both salt treatments, indicating enhanced salt tolerance of the BS line. NMR-based metabolite proﬁling and PCA analyses indicated a more pronounced shift in key stem metabolites after four weeks of treatment with the YS line compared to the BS line. For example, tryptophan and formate levels increased in the YS line after four weeks of 100 mM salt treatment, while proline and threonine levels varied uniquely compared to other metabolites of the lines. Together, the data indicate that the brown-seeded line has greater sodium tolerance than the yellow-seed line, provide clues to the biochemical underpinnings for the phenotypic variation, and highlight the utility of B. carinata as a bioreﬁnery crop for saline land.
Keywords: Biorefinery; Brassica carinata; Ethiopian mustard; marginal land; Na₂SO₄ tolerance; stress metabolism

Evaluation of macrozone dimensions by ultrasound and EBSD techniques - Moreau, André; Toubal, Lotfi; Bocher, Philippe; Humbert, Michel; Uta, Elena; Gey, Nathalie (Materials Characterization, 2012)
Titanium alloys are known to have texture heterogeneities, i.e. regions much larger than the grain dimensions, where the local orientation distribution of the grains differs from one region to the next. The electron backscattering diffraction (EBSD) technique is the method of choice to characterize these macro regions, which are called macrozones. Qualitatively, the images obtained by EBSD show that these macrozones may be larger or smaller, elongated or equiaxed. However, often no well-defined boundaries are observed between the macrozones and it is very hard to obtain objective and quantitative estimates of the macrozone dimensions from these data. In the present work, we present a novel, non-destruction ultrasonic technique that provides objective and quantitative characteristic dimensions of the macrozones. The obtained dimensions are based on the spatial autocorrelation function of fluctuations in the sound velocity. Thus, a pragmatic definition of macrozone dimensions naturally arises from the ultrasonic measurement. This paper has three objectives: 1) to disclose the novel, non-destructive ultrasonic technique to measure macrozone dimensions; 2) to propose a quantitative and objective definition of macrozone dimensions adapted to and arising from the ultrasonic measurement, and which is also applicable to the orientation data obtained by EBSD; and 3) to compare the macrozone dimensions obtained using the two techniques on two samples of the near-alpha titanium alloy IMI834. In addition, it was observed that macrozones may present a semi-periodical arrangement.
Keywords: Macrozone; Ultrasound; Titanium; EBSD; Texture; Correlation

Poly(arylene ether) electrolyte membranes bearing aliphatic-chain-linked sulfophenyl pendant groups - Zhang, Qiang; Liu, Baijun; Hu, Wei; Xu, Wan; Jiang, Zhenhua; Xing, Wei; Guiver, Michael D. (Journal of Membrane Science, 2012)
Two series of novel side-chain-acid poly(arylene ether)s bearing aliphatic-chain-linked sulfophenyl pendants are synthesized by direct polycondensation reactions derived from a new sulfonated difluoro-monomer, sodium 4-(3--(4-(2,6-difluorobenzoyl)phenoxy)propoxy)benzenesulfonate. The sulfonation content is readily controlled by adjusting the feed ratios of sulfonated and unsulfonated monomers. The obtained polymers exhibit considerably reduced dimensional swelling and good proton conductivities. It is found that the cyano-functionalized poly(arylene ether)s exhibit lower water uptake and dimensional swelling in comparison with the corresponding SPAE series. SPAEK-3 with an ion exchange capacity of 1.5 mequiv g(-1) has proton conductivity of 0.12 S cm(-1) and water swelling ratio of only 26% at 100 degrees Celsius. Importantly, obvious hydrophobic/hydrophilic phase separation morphology is observed, which may be highly related with their good proton transport ability.
Keywords: Poly(arylene ether)s; Proton exchange membranes; Morphology; Fuel cells

Performance and stability of proton conducting solid oxide fuel cells based on yttrium-doped barium cerate-zirconate thin-film electrolyte - Yoo, Yeong; Lim, Nguon (Journal of Power Sources, 2012)
The high performance anode supported single cells, comprising of BSCF (Ba0.5Sr0.5Co0.8Fe0.2O3−δ)-BCZY (Ba0.98Ce0.6Zr0.2Y0.2O3−δ)//BCZY//NiO–BCZY have been fabricated by wet powder spraying and co-firing for depositing 10–15 μm thin film electrolytes on pre-sintered NiO–BCZY anode discs. The open circuit voltages of single cells were around 1.12–1.13 V at 600 °C indicating negligible gas leakage or mixed conduction through the electrolyte. The maximum power density of 493 mW cm−2 was obtained at 600 °C and 0.7 V under humid air as the oxidant gas and humid 75% H2 in N2 (2.76% H2O) as the fuel gas at a gas flow rate of 100 ml min−1. The area specific resistance of an anode supported button cell of BSCF–BCZY//BCZY//NiO–BCZY in fuel cell mode was about 0.46 Ω cm2 and in the electrolysis mode was 0.26 Ω cm2 at 600 °C, indicating high efficiency, reversible SOFCs. The single cell performance was stable for over 600 h at 600 °C. The stability of BCZY electrolyte in water-containing atmospheres was investigated by exposing sintered BCZY pellets to humid air (2.76% H2O) at 200 °C for 24 h or soaking them in boiling water for 3 h.
Keywords: Yttrium-doped barium cerate-zirconate; Proton conducting SOFCs; Stability; Thin-film electrolyte; Reversible SOFCs

A clustered sulfonated poly(ether sulfone) based on a new fluorene-based bisphenol monomer - Wang, Chenyi; Shin, Dong Won; Lee, So Young; Kang, Na Rae; Robertson, Gilles P.; Lee, Young Moo; Guiver, Michael D. (Journal of Materials Chemistry, 2012)
A new fluorene-based bisphenol monomer containing two pendant phenyl groups, 9,9-bis(3-phenyl-4-hydroxy)phenyl-fluorene, was readily synthesized in high yield by a one-step reaction from inexpensive starting materials. A series of poly(ether sulfone)s with clustered sulfonic acid groups was prepared for fuel cell applications by polycondensation of the new monomer with bis(4-hydroxyphenyl)sulfone and bis(4-fluorophenyl)sulfone, followed by sulfonation exclusively on the fluorene rings and pendant phenyl rings, using concentrated sulfuric acid at room temperature. The sulfonated polymers gave tough, flexible, and transparent membranes by solvent casting. The ionic exchange capacity (IEC), water-uptake, dimensional stabilities, mechanical properties, thermal and oxidative stabilities as well as proton conductivities and single fuel cell properties of the membranes were investigated. The membranes with high IEC values show high proton transport properties, and their proton conductivities exhibit lower dependence on relative humidity compared with typical aromatic ion exchange membranes. 4-SPES-38 with an IEC value of 2.23 mequiv. g−1 displays comparable fuel cell performance with Nafion 212 under low humidity conditions.

Morphological transformation during cross-linking of a highly sulfonated poly(phenylene sulfide nitrile) random copolymer - Lee, So Young; Kang, Na Rae; Shin, Dong Won; Lee, Chang Hyun; Lee, Kwan-Soo; Guiver, Michael D.; Li, Nanwen; Lee, Young Moo (Energy and Environmental Science, 2012)
We present a new approach of morphological transformation for effective proton transport within ionomers, even at partially hydrated states. Highly sulfonated poly(phenylene sulfide nitrile) (XESPSN) random network copolymers were synthesized as alternatives to state-of-the-art perfluorinated polymers such as Nafion®. A combination of thermal annealing and cross-linking, which was conducted at 250 °C by simple trimerisation of ethynyl groups at the chain termini, results in a morphological transformation. The resulting nanophase separation between the hydrophilic and hydrophobic domains forms well-connected hydrophilic nanochannels for dramatically enhanced proton conduction, even at partially hydrated conditions. For instance, the proton conductivity of XESPSN60 was 160% higher than that of Nafion® 212 at 80 °C and 50% relative humidity. The water uptake and dimensional swelling were also reduced and mechanical properties and oxidative stability were improved after three-dimensional network formation. The fuel cell performance of XESPSN membranes exhibited a significantly higher maximum power density than that of Nafion® 212 under partially hydrated environments.

Proton-conducting membranes from poly(ether sulfone)s grafted with sulfoalkylamine - Wang, Chenyi; Lee, So Young; Shin, Dong Won; Kang, Na Rae; Lee, Young Moo; Guiver, Michael D. (Journal of Membrane Science, 2012)
Highly sulfonated poly(ether sulfone)s with densely populated flexible acid side chains were prepared for fuel cell applications by polycondensation of 3,3'-dihydroxybenzidine with bis(4-fluorophenyl)sulfone and 4,4′-biphenol, followed by postsulfonation using 1,4-butanesultone at room temperature. The sulfonated polymers gave tough, flexible, and transparent membranes by solvent casting. The membranes had high ion exchange capacity (IEC) values (2.47–2.95 mequiv/g) and displayed good proton conductivities in the range of 13.90–20.90×10−2 and 1.08–2.21×10−2 S/cm at 95% and 35% relative humidity (RH) (80 °C), respectively. In particular, the S-PES-55 membrane with the highest IEC value showed higher or comparable proton conductivity than that of Nafion 212 in the range of 35–95% RH. The morphologies of these membranes were investigated by TEM analysis, which exhibited well-connected hydrophilic channels due to their high IEC values and densely populated flexible acid side chains. In contrast with many reported highly sulfonated polymers, the membranes showed good dimensional stability regardless of their high IEC values.
Keywords: Sulfonated polymer; High IEC values; Proton conductivity; Proton exchange membrane

Target of Rapamycin signaling regulates metabolism, growth, and life span in Arabidopsis - Ren, Maozhi; Venglat, Prakash; Qiu, Shuqing; Feng, Li; Cao, Yongguo; Wang, Edwin; Xiang, Daoquan; Wang, Jinghe; Alexander, Danny; Chalivendra, Subbaiah; Logan, David; Mattoo, Autar; et al. (The Plant Cell, 2012)
Target of Rapamycin (TOR) is a major nutrition and energy sensor that regulates growth and life span in yeast and animals. In plants, growth and life span are intertwined not only with nutrient acquisition from the soil and nutrition generation via photosynthesis but also with their unique modes of development and differentiation. How TOR functions in these processes has not yet been determined. To gain further insights, rapamycin-sensitive transgenic Arabidopsis thaliana lines (BP12) expressing yeast FK506 Binding Protein12 were developed. Inhibition of TOR in BP12 plants by rapamycin resulted in slower overall root, leaf, and shoot growth and development leading to poor nutrient uptake and light energy utilization. Experimental limitation of nutrient availability and light energy supply in wild-type Arabidopsis produced phenotypes observed with TOR knockdown plants, indicating a link between TOR signaling and nutrition/light energy status. Genetic and physiological studies together with RNA sequencing and metabolite analysis of TOR-suppressed lines revealed that TOR regulates development and life span in Arabidopsis by restructuring cell growth, carbon and nitrogen metabolism, gene expression, and rRNA and protein synthesis. Gain- and loss-of-function Ribosomal Protein S6 (RPS6) mutants additionally show that TOR function involves RPS6-mediated nutrition and light-dependent growth and life span in Arabidopsis.

Construction of genetic linkage map and mapping of QTL for seed color in Brassica rapa - Kebede, Berisso; Cheema, Kuljit; Greenshields, David L.; Li, Changxi; Selvaraj, Gopalan; Rahman, Habibur (Genome, 2012)
A genetic linkage map of Brassica rapa L. was constructed using recombinant inbred lines (RILs) derived from a cross between yellow-seeded cultivar Sampad and a yellowish brown seeded inbred line 3-0026.027. The RILs were evaluated for seed color under three conditions: ﬁeld plot, greenhouse, and controlled growth chambers. Variation for seed color in the RILs ranged from yellow, like yellow sarson, to dark brown/black even though neither parent had shown brown/black colored seeds. One major QTL (SCA9-2) and one minor QTL (SCA9-1) on linkage group (LG) A9 and two minor QTL (SCA3-1, SCA5-1) on LG A3 and LG A5, respectively, were detected. These collectively explained about 67% of the total phenotypic variance. SCA9-2 mapped in the middle of LG A9, explained about 55% phenotypic variance, and consistently expressed in all environments. The second QTL on LG A9 was ~70 cM away from SCA9-2, suggesting that independent assortment of these QTLs is possible. A digenic epistatic interaction was found between the two main effect QTL on LG A9; and the epistasis X environment interaction was nonsigniﬁcant, suggesting stability of the interaction across the environments. The QTL effect on LG A9 was validated using simple sequence repeat (SSR) markers from the two QTL regions of this LG on a B₁S₁ population (F₁ backcrossed to Sampad followed by self-pollination) segregating for brown and yellow seed color, and on their self-pollinated progenies (B₁S₂). The SSR markers from the QTL region SCA9-2 showed a stronger linkage association with seed color as compared with the marker from SCA9-1. This suggests that the QTL SCA9-2 is the major determinant of seed color in the A genome of B. rapa.
Keywords: Brassica rapa; yellow sarson; seed color; linkage map; QTL mapping; Brassica rapa; yellow sarson; couleur des graines; carte génétique; cartographie QTL

Simulation of membrane-based CO2 capture in a coal-fired power plant - Shao, Pinghai; Dal-Cin, Mauro M.; Guiver, Michael D.; Kumar, Ashwani (Journal of Membrane Science, 2012)
A two-stage membrane process is designed for CO2 capture from coal-fired power plants. Vacuum operation on the permeate side of the membrane is the preferred option to reduce the power demand for compressing the huge feed volume. The energy recovered from the CO2-depleted emission stream and the energy consumed for post-capture CO2 liquefaction are considered in this simulation study. A numerical modeling of the membrane process and a brief description on assessing both the capital and operating costs of the process are provided. It is found that the membrane area requirement is dominated by recovery of the lower concentrations of CO2 in the tail portion of the flue gas stream. Process optimizations allowing the minimal CO2 capture cost or minimal power demand indicate that current membrane technology is promising for flue gas CO2 capture, assuming a permeance of 1000 GPU and CO2/N2 selectivity of 30. The potential of membrane technology for CO2 capture was also explored by using membranes with a CO2/N2 selectivity of 50 and 200.
Keywords: Mebrane; Permeance; Selectivity; CO2 capture; Flue gas; Capital and operating cost; Process optimization; Power demand; Liquefaction: cost of energy

Ordered alloy formation for Pt3Fe/C, PtFe/C and Pt5.75Fe5.75Cuy/CO2-reduction electro-catalysts - Chen, L.; Bock, C.; Mercier, P. H. J.; Macdougall, B. R. (Electrochimica Acta, 2012)
Carbon supported Pt3Fe, PtFe and Pt5.75Fe5.75Cu catalysts are prepared via the impregnation of Fe and/or Cu-nitrate precursor salts onto a preformed nano-sized Pt/C catalyst. They are referred to as Pt3Fe/C, PtFe/C and Pt5.75Fe5.75Cu/C catalysts and the subscripts refer to the nominal Pt, Fe and Cu atomic ratios. The final catalysts are obtained by annealing the impregnated samples in a H2 enriched atmosphere. Pt5.75Fe6.75/C, Pt5.75Cu6.75/C and Pt5.75Fe5.75Cu2/C catalysts were also made. The as-prepared catalysts are characterized using X-ray diffraction, transmission electron microscopy, standard electrochemical methods and probed for the electrochemical O2 reduction reaction (orr). Rietveld analyses reveal that [Fm-3m] Pt, cubic [Pm-3m] Pt3Fe and tetragonal [P4/mmm] PtFe structure types are made. In case of the Pt5.75Fe5.75Cu/C catalyst, a nano-sized carbon-supported single-phase catalyst of [P4/mmm] structure is found to be made at 800 °C, with Pt and Fe ordered on separate lattice planes, while Cu is distributed randomly onto both Pt and Fe atomic planes. The PtFe/C equivalent catalyst contains in addition a separate Fe phase as well as a slightly disordered [P4/mmm] phase. Pt5.75Cu6.75/C forms a disordered cubic [Fm-3m] alloy structure. The activity toward the orr was measured after 70 potential cycling, which can cause beneficial changes to the catalysts. In case of the specific orr activity, a dependence on the catalyst series is observed as follows: Pt5.75Fe5.75Cu/C [P4/mmm] > PtFe/C [P4/mmm] > Pt3Fe/C [Pm-3 m] ≈ Pt5.75Cu6.75/C [Fm-3m] > Pt/C [Fm-3m]. The highest orr mass activities are also found for the Pt5.75Fe5.75Cu/C and subsequently for the PtFe/C catalysts. Estimated orr activities are well within the range reported in the literature. In fact the specific orr activities compare to results reported for so called de-alloyed catalyst that are among the highest orr mass activities reported in the recent literature.
Keywords: PEMFCs; O2 electro-reduction catalyst; Alloy formation; Ordered alloys; Rietveld fitting

Poly(arylene ether sulfone) proton exchange membranes with flexible acid side chains - Wang, Chenyi; Shin, Dong Won; Lee, So Young; Kang, Na Rae; Lee, Young Moo; Guiver, Michael D. (Journal of Membrane Science, 2012)
New monomers containing two or four pendent methoxyphenyl groups were synthesized by bromination of bis(4-fluorophenyl)sulfone, followed by Suzuki coupling with 4-methoxybenzeneboronic acid. Copoly(arylene ether sulfone)s containing methoxypheynl groups (2-MPAES-xx and 4-MPAES-xx) based on the corresponding monomers were prepared by aromatic nucleophilic substitution (SNAr) polycondensation. After demethylation of the methoxy group to the reactive hydroxyl group, the respective side chain-type sulfonated copolymers (2-MPAES-xx and 4-MPAES-xx) were obtained by sulfobutylation. Flexible and tough membranes having good mechanical strength were obtained by solution casting of all copolymers. The sulfonated copolymers with two or four pendent sulfobutoxyphenyl groups had high proton conductivities in the range of 0.108-0.258 S/cm for 2-SPAES-xx and 0.135-0.194 S/cm for 4-SPAES-xx at 80 degrees Celsius, respectively. The methanol permeabilities of these membranes were in the range of 1.59 x 10(-7) - 4.69 x 10(-7) cm(2)/s, which is much lower than Nafion® (15.5 x 10(-7) cm(2)/s). 2-SPAES-xxand 4-SPAES-xx display comparatively better balance between proton conductivity and water swelling than the analogous poly(arylene ether sulfone)s containing pendent sulfophenyl groups. A combination of high proton conductivities, low water uptake, and low methanol permeabilities for some of the obtained copolymers indicated that they have some of the requisite properties for proton exchange membranes in fuel cell applications.
Keywords: Sulfonated poly(arylene ether sulfone); Polymer electrolyte membranes; Proton conductivity; Dimensional stability

Design and economics of a hybrid membrane–temperature swing adsorption process for upgrading biogas - Shao, Pinghai; Dal-cin, Mauro; Kumar, Ashwani; Li, Haibin; Singh, Davinder Paul (Journal of Membrane Science, 2012)
Processing biogas from wastewater digesters allows recovery of valuable methane and reduction in green house gas emissions. A two-stage membrane process, coupled with a temperature-swing-adsorption (TSA) as pre-treatment, was designed to generate pipeline quality methane. To improve methane recovery and process energy efficiency, the non-product streams of the membrane process were recycled and the permeate of the first membrane stage was maintained at a given pressure as the driving force for second membrane stage. The membrane process design was optimized by minimizing the objective function; the overall processing cost. It was found the membrane approach excels the PSA for producing pipeline quality methane (97% purity) in terms of methane recovery, processing cost and lower emissions. A techno-economic analysis showed that the payback time for an operation processing 200 Nm(3)/h of biogas was 6.8 months.
Keywords: Process design and optimization; Hollow fiber membrane; Pressure ratio; Recycling; Biogas emission; Capital and operating cost; Economic analysis

An experimental investigation of HCCI combustion stability using n-heptane - Li, Hailin; Neill, W. Stuart; Chippior, Wallace L. (Journal of Energy Resources Technology, 2012)
The combustion stability of a single-cylinder homogeneous charge compression ignition (HCCI) engine operated with n-heptane was experimentally investigated over a range of engine speeds (N), intake temperatures and pressures, compression ratios (CR), air/fuel ratios (AFR), and exhaust gas recirculation (EGR) rates. These parameters were varied to alter the combustion phasing from an overly advanced condition where engine knock occurred to an overly retarded condition where incomplete combustion was observed with excessive emissions of carbon monoxide (CO) and unburned hydrocarbons (UHC). The combustion stability was quantified by the coefficients of variation in indicated mean effective pressure (COVimep ) and peak cylinder pressure (COVPmax ). Cycle-to-cycle variations in the HCCI combustion behavior of this engine were shown to depend strongly on the combustion phasing, defined in this study as the crank angle position where 50% of the energy was released (CA50). In general, combustion instability increased significantly when the combustion phasing was overly retarded. The combustion phasing was limited to conditions where the COVimep was 5% or less as engine operation became difficult to control beyond this point. Based on the experimental data, the combustion phasing limit was approximately a linear function of the amount of fuel inducted in each cycle. Stable HCCI combustion could be obtained with progressively retarded combustion phasing as the fuel flow rate increased. In comparison, stable HCCI combustion was only obtained under very advanced combustion phasing for low load operating conditions. Investigation of the experimental data reveals that the cyclic variations in HCCI combustion were due to cycle-to-cycle variations in total heat release (THR). The combustion completeness of the previous cycle affected the in-cylinder bulk mixture conditions and resultant heat release process of the following engine cycle.
Keywords: HCCI; Combustion stability; Combustion phasing; Fuel flow rate

The Chaperonin-60 universal target is a barcode for bacteria that enables de novo assembly of metagenomic sequence data - Links, Matthew G.; Dumonceaux, Tim J.; Hemmingsen, Sean M.; Hill, Janet E. (PLoS ONE, 2012)
Barcoding with molecular sequences is widely used to catalogue eukaryotic biodiversity. Studies investigating the community dynamics of microbes have relied heavily on gene-centric metagenomic profiling using two genes (16S rRNA and cpn60) to identify and track Bacteria. While there have been criteria formalized for barcoding of eukaryotes, these criteria have not been used to evaluate gene targets for other domains of life. Using the framework of the International Barcode of Life we evaluated DNA barcodes for Bacteria. Candidates from the 16S rRNA gene and the protein coding cpn60 gene were evaluated. Within complete bacterial genomes in the public domain representing 983 species from 21 phyla, the largest difference between median pairwise inter- and intra-specific distances (“barcode gap”) was found from cpn60. Distribution of sequence diversity along the ~555 bp cpn60 target region was remarkably uniform. The barcode gap of the cpn60 universal target facilitated the faithful de novo assembly of full-length operational taxonomic units from pyrosequencing data from a synthetic microbial community. Analysis supported the recognition of both 16S rRNA and cpn60 as DNA barcodes for Bacteria. The cpn60 universal target was found to have a much larger barcode gap than 16S rRNA suggesting cpn60 as a preferred barcode for Bacteria. A large barcode gap for cpn60 provided a robust target for species-level characterization of data. The assembly of consensus sequences for barcodes was shown to be a reliable method for the identification and tracking of novel microbes in metagenomic studies.
Keywords: Amplicon; article; bacterial gene; bacterial genome; bacterium detection; cnp60 gene; DNA barcoding; Escherichia coli; gene sequence; gene targeting; genetic code; genetic identification; genetic organization; genetic variability; metagenomics; microbial community; nonhuman; pyrosequencing; RNA gene

Enhancement of biological mass spectrometry by using separations based on changes in ion mobility (FAIMS and DMS) - Purves, Randy W. (Analytical and Bioanalytical Chemistry, 2012)
Analysis of complex biological samples for lowlevel analytes by liquid chromatography–tandem mass spectrometry (LC–MS/MS) often requires additional selectivity. Differential mobility techniques (FAIMS and DMS) have been shown to enhance LC–MS/MS analyses by separating ions in the gas-phase on a millisecond timescale by use of a mechanism that is complementary to both liquid chromatography and mass spectrometry. In this overview, a simplified description of the operation of these devices is given and an example presented that illustrates the utility of FAIMS (DMS) for solving a challenging analytical assay. Important recent advances in the field, including work with gas modifiers, are presented, along with an outlook for the technology.
Keywords: Bioanalytical methods; biological samples; HPLC; mass spectrometry; FAIMS; DMS

Characterization of novel Triacylglycerol Estolides from the seed oil of Mallotus philippensis and Trewia nudiflora - Smith, Mark A.; Zhang, Haixia; Forseille, Li; Purves, Randy W. (Lipids, 2012)
Triacylglycerol estolides have been reported as components of the seed oil of a number of plant species and are generally associated with the presence of fatty acids containing hydroxyl groups. We have used MALDI-TOF MS to examine the intact acylglycerol species present in the seed oils of two plants that produce kamlolenic acid (18-hydroxy-D9cis,11trans,13trans-octadecatrienoic acid). Mallotus philippensis and Trewia nudiﬂora were both shown to produce seed oil rich in TAG-estolides. Analysis by MALDI-TOF MS/MS demonstrated that the TAG-estolides had a structure different to that previously proposed after enzymatic digestion of the oil. Acylglycerols containing up to 14 fatty acids were detected but fatty acid estolides were only present in a single position on the glycerol backbone, with predominantly non-hydroxyl fatty acids in the remaining two positions. Increased numbers of fatty acids per glycerol backbone were accounted for by the presence of fatty acid estolides containing a correspondingly greater number of fatty acids. For example, acylglycerols containing seven fatty acids had a fatty acid estolide of ﬁve fatty acids at one position on the glycerol backbone. Both capped and uncapped fatty acid estolides, with a free hydroxyl group, were present, with capped fatty acid estolides being more abundant in T. nudiﬂora and uncapped fatty acid estolides in M. philippensis.
Keywords: Triacylglycerol; Estolide; Seed oil; Kamlolenic acid; Mallotus philippensis; Trewia nudiflora; Conjugated fatty acids; MALDI-TOF MS

Metabolic interactions between the Lands Cycle and the Kennedy Pathway of Glycerolipid synthesis in Arabidopsis developing seeds - Wang, Liping; Shen, Wenyun; Kazachkov, Michael; Chen, Guanqun; Chen, Qilin; Carlsson, Anders S.; Stymne, Sten; Weselake, Randall J.; Zou, Jitao (The Plant Cell, 2012)
It has been widely accepted that the primary function of the Lands cycle is to provide a route for acyl remodeling to modify fatty acid (FA) composition of phospholipids derived from the Kennedy pathway. Lysophosphatidylcholine acyltransferase (LPCAT) is an evolutionarily conserved key enzyme in the Lands cycle. In this study, we provide direct evidence that the Arabidopsis thaliana LPCATs, LPCAT1 and LPCAT2, participate in the Lands cycle in developing seeds. In spite of a substantially reduced initial rate of nascent FA incorporation into phosphatidylcholine (PC), the PC level in the double mutant lpcat1 lpcat2-2 remained unchanged. LPCAT deﬁciency triggered a compensatory response of de novo PC synthesis and a concomitant acceleration of PC turnover that were attributable at least in part to PC deacylation. Acyl-CoA proﬁle analysis revealed complicated metabolic alterations rather than merely reduced acyl group shufﬂing from PC in the mutant. Shifts in FA stereospeciﬁc distribution in triacylglycerol of the mutant seed suggested a preferential retention of saturated acyl chains at the stereospeciﬁc numbering (sn)-1 position from PC and likely a channeling of lysophosphatidic acid, derived from PC, into the Kennedy pathway. Our study thus illustrates an intricate relationship between the Lands cycle and the Kennedy pathway.

Regulation of Phytohormone biosynthesis and accumulation in Arabidopsis following treatment with commercial extract from the marine Macroalga Ascophyllum nodosum - Wally, Owen S. D.; Critchley, Alan T.; Hiltz, David; Craigie, James S.; Han, Xiumei; Zaharia, L. Irina; Abrams, Suzanne R.; Prithiviraj, Balakrishnan (Journal of Plant Growth Regulation, 2012)
Seaweeds and their extracts have been used for centuries in agriculture to improve plant growth and impart stress tolerance. There has been historical evidence that phytohormones present in seaweeds lead to these effects, but questions of this mode of action have always been raised. By quantifying phytohormones in seaweed extracts coupled with the use of phytohormone biosynthetic and insensitive mutants, we conclude that the phytohormone levels present within the extracts are insufﬁcient to cause signiﬁcant effects in plants when extracts are applied at recommended rates. However, components within seaweed extracts may modulate innate pathways for the biosynthesis of phytohormones in plants. Phytohormone proﬁles of plant tissue extracts were analyzed following root application of a commercial seaweed extract produced from Ascophyllum nodosum (ANE) to in vitro-grown Arabidopsis plants. We found an increase in total concentration of cytokinins (CKs), in particular, of trans-zeatin-type CKs, 24 and 96 h after ANE application, with an increase in cis-zeatintype CKs observed at 144 h. Concomitantly, increases in abscisic acid (ABA) and ABA catabolite levels were observed whereas auxin levels were reduced. Additionally, the proﬁle of transcripts revealed that CK biosynthetic genes were upregulated, whereas the CK catabolic genes were repressed at 24 and 96 h following ANE application. Not surprisingly, the transcripts of ABA biosynthetic genes were increased whereas the auxin biosynthetic genes were repressed. These corroborated ﬁndings are the ﬁrst to help explain the underlying physiological beneﬁts derived from the application of ANE to plants.
Keywords: Abscisic acid; arabidopsis; Ascosphyllum nodosum; Auxins; Cytokinins; gene expression; Phytohormones

Analysis of expressed sequence tags in Brassica napus cotyledons damaged by crucifer flea beetle feeding - Gruber, Margaret; Wu, Limin; Links, Matthew; Gjetvaj, Branimir; Durkin, Johnathan; Lewis, Christopher; Sharpe, Andrew; Lydiate, Derek; Hegedus, Dwayne (Genome, 2012)
The molecular basis of canola (Brassica napus L.) susceptibility to the crucifer flea beetle (FB, Phyllotreta cruciferae Goeze) was investigated by comparing transcript representation in FB-damaged and undamaged cotyledons. The B. napus cotyledon transcriptome increased and diversified substantially after FB feeding damage. Twenty-two genes encoding proteins with unknown function, six encoding proteins involved in signaling, and a gene encoding a B-box zinc finger transcription factor were moderately or strongly changed in representation with FB feeding damage. Zinc finger and calciumdependent genes formed the largest portion of transcription factors and signaling factors with changes in representation. Six genes with unknown function, one transcription factor, and one signaling gene specific to the FB-damaged library were co-represented in a FB-damaged leaf library. Out of 188 transcription factor and signaling gene families screened for “early” expression changes, 16 showed changes in expression within 8 h. Four of these early factors were zinc finger genes with representation only in the FB-damaged cotyledon. These genes are now available to test their potential at initiating or specifying cotyledon responses to crucifer FB feeding.
Keywords: Brassica napus; cotyledon EST representation; flea beetle Phyllotreta; host plant molecular response; Brassica napus; catalogue d'EST chez le cotylédon; altise des crucifères Phyllotetra; réponses moléculaires de l'hôte

Aerobic mineralization of Nitroguanidine by Variovorax strain VC1 isolated from soil - Perreault, Nancy N.; Halasz, Annamaria; Manno, Dominic; Thiboutot, Sonia; Ampleman, Guy; Hawari, Jalal (Environmental Science & Technology, 2012)
Nitroguanidine (NQ) is an energetic materialthat is used as a key ingredient of triple-base propellants and is currently being considered as a TNT replacement in explosive formulations. NQ was eﬃciently degraded in aerobic microcosms when a carbon source was added. NQ persisted in unamended microcosms or under anaerobic conditions. An aerobic NQ-degrading bacterium, Variovorax strain VC1, was isolated from soil microcosms containing NQ as the sole nitrogen source. NQ degradation was inhibited in the presence of a more favorable source of nitrogen. Resting cells of VC1 degraded NQ eﬀectively (54 μmol h⁻¹g⁻¹ protein) giving NH₃ (50.0%), nitrous oxide (N₂O) (48.5%) and CO₂ (100%). Disappearance of NQ was accompanied by the formation of a key intermediate product that we identiﬁed as nitrourea by comparison with a reference material. Nitrourea is unstable in water and suﬀered both biotic and abiotic decomposition to eventually give NH₃, N₂O, and CO₂. However, we were unable to detect urea. Based on products distribution and reaction stoichiometry, we suggested that degradation of NQ, O₂NN≕C(NH₂)₂, might involve initial enzymatic hydroxylation of the imine, ⋯C≕N⋯ bond, leading ﬁrst to the formation of the unstable α-hydroxynitroamine intermediate, O₂NNHC(OH)-(NH₂)₂, whose decomposition in water should lead to the formation of NH₃, N₂O, and CO₂.NQ biodegradation was induced by nitroguanidine itself, L-arginine, and creatinine, all being iminic compounds containing a guanidine group. This ﬁrst description of NQ mineralization by a bacterial isolate demonstrates the potential for eﬃcient microbial remediation of NQ in soil.
Keywords: A-carbon; aerobic mineralization; bacterial isolates; intermediate product; L-Arginine; nitrogen sources; Nitroguanidine; Nitrous oxide; reaction stoichiometry; reference material; resting cells; soil microcosms

Environmental characterization of military training ranges for munitions-related contaminants : understanding and minizing the environmental impacts of live-fire training - Thiboutot, Sonia; Ampleman, Guy; Brochu, Sylvie; Diaz, Emmanuela; Poulin, I.; Martel, Richard; Al-Hawari, Jalal; Sunahara, Geoffrey I.; Walsh, Michael R.; Walsh, Marianne E.; Jenkins, T. F. (International Journal of Energetic Materials and Chemical Propulsion, 2012)
An important R&D effort was dedicated to the characterization of ranges and training areas and to the study of the environmental fate and the ecotoxicological impacts of munitions constituents in the last 20 years in Canada and the United States. Major environmental issues were identified, and the sources of munitions constituents in training ranges are better understood. Protocols were developed for collecting representative soil samples and their effective processing. In the last years, a large effort was dedicated to the measurement of the mass of munitions constituents deposited both at target impact areas and at firing positions, which led to a good estimation of source terms of contaminants. In Canadian ranges and training areas, efforts were also dedicated to characterize both surface and subsurface aquifers and geology, and detailed hydrogeological and geological mapping. All the data acquired over the last years have been used to build hazards and vulnerability maps, which can be combined to draw risk maps that represent great assets from a risk-management perspective. The next step is the development of environmentally sound solutions that will sustain military training and maintain force readiness. In order to achieve that goal, efforts are committed to the modification of actual live-firing activities to minimize their environmental adverse impacts. Finally, Canada is aiming at developing greener and insensitive munitions that will ease the environmental pressure. This paper is a summary of what has been done in North America toward understanding and minimizing the environmental footprint of munitions.
Keywords: Characterization; munitions; unexploded ordnances; live fire; training ranges; environmental impact; deposition rate; munitions constituents; fate; ecotoxicology; hydrogeology; explosives; propellants

The substrate-bound crystal structure of a Baeyer–Villiger monooxygenase exhibits a Criegee-like conformation - Yachnin, Brahm J.; Sprules, Tara; McEvoy, Michelle B.; Lau, Peter C. K.; Berghuis, Albert M. (Journal of the American Chemical Society, 2012)
The Baeyer–Villiger monooxygenases (BVMOs) are a family of bacterial flavoproteins that catalyze the synthetically useful Baeyer–Villiger oxidation reaction. This involves the conversion of ketones into esters or cyclic ketones into lactones by introducing an oxygen atom adjacent to the carbonyl group. The BVMOs offer exquisite regio- and enantiospecificity while acting on a wide range of substrates. They use only NADPH and oxygen as cosubstrates, and produce only NADP+ and water as byproducts, making them environmentally attractive for industrial purposes. Here, we report the first crystal structure of a BVMO, cyclohexanone monooxygenase (CHMO) from Rhodococcus sp. HI-31 in complex with its substrate, cyclohexanone, as well as NADP+ and FAD, to 2.4 Å resolution. This structure shows a drastic rotation of the NADP+ cofactor in comparison to previously reported NADP+-bound structures, as the nicotinamide moiety is no longer positioned above the flavin ring. Instead, the substrate, cyclohexanone, is found at this location, in an appropriate position for the formation of the Criegee intermediate. The rotation of NADP+ permits the substrate to gain access to the reactive flavin peroxyanion intermediate while preventing it from diffusing out of the active site. The structure thus reveals the conformation of the enzyme during the key catalytic step. CHMO is proposed to undergo a series of conformational changes to gradually move the substrate from the solvent, via binding in a solvent excluded pocket that dictates the enzyme’s chemospecificity, to a location above the flavin–peroxide adduct where catalysis occurs.
Keywords: Active site; Baeyer Villiger oxidation; Baeyer-Villiger monooxygenases; bound structure; Carbonyl groups; cofactors; conformational change; cosubstrates; cyclic ketones; cyclohexanon monooxygenase; cyclohexanones; enantiospecificity; Oxygen atom; Rhodococcus sp; substrate-bound

Pretreating mixed anaerobic communities from different sources : correlating the hydrogen yield with hydrogenase activity and microbial diversity - Pendyala, Brahmaiah; Chaganti, Subba Rao; Lalman, Jerald A.; Shanmugam, Saravanan R.; Heath, Daniel D.; Lau, Peter C. K. (International Journal of Hydrogen Energy, 2012)
In this study, granular and ﬂocculated anaerobic mixed cultures were pretreated using heat, shock loading, acid, alkali, linoleic acid (LA) and 2-bromoethane sulphonic acid (BESA). Under mesophilic conditions (37°C) and an initial pH value of 6.0, higher H₂ yields were observed for the ﬂocculated cultures when compared to the granular cultures. The maximum yield for granular cultures treated acid, BESA or LA were statistically the same. Butyric acid fermentation was dominant in a majority of the treated cultures. The maximum hydrogenase evolution speciﬁc activity (ESA) (124 ± 8 Ue mg VSS⁻¹) at 37°C correlated with the maximum H₂ yield for the LA treated ﬂocculated cultures (1.69 ± 0.18 mol mol⁻¹ glucose). The microbial diversity data clearly showed that the low H₂ yield in the granular cultures was due to the lower proportion of H₂ producers. A principle component analysis (PCA) revealed that the LA treated ﬂocculated and granular cultures were grouped together and showed more diversity in comparison to other pretreatment methods.
Keywords: Mixed anaerobic cultures; hydrogen; hydrogenase activity; T-RFLP; microbial diversity; pretreatment

Catalysis using gold nanoparticles decorated on nanocrystalline cellulose - Lam, Edmond; Hrapovic, Sabahudin; Majid, Ehsan; Chong, Jonathan H.; Luong, John H. T. (Nanoscale, 2012)
A novel nanocomposite was prepared by deposition of carbonate-stabilized Au nanoparticles (AuNPs) onto the surface of poly(diallyldimethyl ammonium chloride) (PDDA)-coated carboxylated nanocrystalline cellulose (NCC). The hybrid material possessed AuNPs (1.45% by weight) with an average diameter of 2.95 ± 0.06 nm. The catalytic activity of AuNP/PDDA/NCC for reducing 4-nitrophenol to 4-aminophenol was compared to other Au-supported composites. An activation energy of 69.2 kJ mol⁻¹ was obtained for the reaction. Indeed, the reaction rate constant k of (5.1 ± 0.2) x 10⁻³ s⁻¹ was comparable to the benchmark literature value obtained using AuNPs (<5 nm in diameter) decorated on a network of crystalline cellulose ﬁbers. Our strategy promotes the use of natural resources to prepare reusable hybrid inorganic–organic materials for important reactions with facilitated product isolation/puriﬁcation.
Keywords: 4-aminophenols; 4-Nitrophenol; Ammonium chloride; Au nanoparticle; Average diameter; Crystalline cellulose; Gold Nanoparticles; Hybrid inorganic-organic; Nanocrystalline cellulose; Product isolation

Laser shockwave technique for characterization of nuclear fuel plate interfaces - Perton, M.; Lévesque, D.; Monchalin, J.-P.; Lord, M.; Smith, J. A.; Rabin, B. H. (Review of Progress in Qualitative Nondestructive Evaluation, 2012)
The US National Nuclear Security Agency is tasked with minimizing the worldwide use of high-enriched uranium. One aspect of that effort is the conversion of research reactors to monolithic fuel plates of low-enriched uranium. The manufacturing process includes hot isostatic press bonding of an aluminum cladding to the fuel foil. The Laser Shockwave Technique (LST) is here evaluated for characterizing the interface strength of fuel plates using depleted Uranium/Mo foils. LST is a non-contact method that uses lasers for the generation and detection of large amplitude acoustic waves and is therefore well adapted to the quality assurance of this process. Preliminary results show a clear signature of well-bonded and debonded interfaces and the method is able to classify/rank the bond strength of fuel plates prepared under different HIP conditions.
Keywords: Laser ultrasonics; Shock waves; Adhesion testing; Nuclear fuel plate

Real-time monitoring of combustion instability in a homogeneous charge compression ignition (HCCI) engine using cycle-by-cycle exhaust temperature measurements - Gardiner, David P.; Neill, W. Stuart; Chippior, Wallace L. (Proceedings of the 2012 Fall Technical Conference of the ASME Internal Combustion Engine Division (ICEF2012), 2012)
This paper describes an experimental study concerning the feasibility of monitoring the combustion instability levels of an HCCI engine based upon cycle-by-cycle exhaust temperature measurements. The test engine was a single cylinder, four-stroke, variable compression ratio Cooperative Fuel Research (CFR) engine coupled to an eddy current dynamometer. A rugged exhaust temerature sensor equipped with special signal processing circuitry was installed near the engine exhaust port. Reference measurements were provided by a laboratory grade, water-cooled cylinder pressure transducer. The cylinder pressure measurements were used to calculate the Coefficient of Variation of Indicated Mean Effective Pressure (COV of IMEP) for each operating condition tested. Experiments with the HCCI engine confirmed that cycle-by-cycle variations in exhaust temperature were present, and were of sufficient magnitude to be captured for processing as high fidelity signal waveforms. There was a good correlation between the variability of the exhaust temperature signal and the COV of IMEP throughout the operating range that was evaluated. The correlation was particularly strong at the low levels of COV of IMEP (2-3%), where production engines would typically operate. A real-time combustion instability signal was obtained from cycle-by-cycle exhaust temperature measurements, and used to provide feedback to the fuel injection control system. Closed loop operation of the HCCI engine was achieved in which the engine was operated as lean as possible while maintaining the COV level at or near 2.5%.

Soot formation in a laminar ethylene/air diffusion flame at pressures from 1 to 8atm - Guo, Hongsheng; Gu, Zhongzhu; Thomson, Kevin A.; Smallwood, Gregory J.; Baksh, Fazil F. (Proceedings of the Combustion Institute, 2012)
The effect of pressure on soot formation in a laminar ethylene/air coflow diffusion flame was investigated by experiments and numerical simulation at pressures from 1 to 8 atm. Soot volume fraction was measured by the diffuse-light two-dimensional line-of-sight attenuation optical diagnostic method and calculated by moments model and a relatively detailed gas phase chemistry. The numerical model successfully captured the variation of soot volume fraction with increasing pressure. The detailed analysis of numerical simulation results suggests that although the rates of all soot formation sub-processes increase with increasing pressure, the rates of increase of these sub-processes differ, with that of PAH condensation being the fastest, followed by those of inception and acetylene addition, respectively. At atmosphere pressure, acetylene addition contributes most to soot formation in terms of the overall formed soot mass, while the contribution of PAH condensation significantly increases at high pressures. The variation in the soot formation mechanism is due to the different increase rates of the mole concentrations and formation of several key species that significantly affect soot inception, acetylene addition and PAH condensation.
Keywords: Soot; PAH; Laminar diffusion flame; High pressure

ThermoPoD : a reliability study on active infrared thermography for the inspection of composite materials - Duan, Yuxia; Servais, Pierre; Genest, Marc; Ibarra-Castanedo, Clemente; Maldague, Xavier P. V. (Journal of Mechanical Science and Technology, 2012)
In this study, a Probability of Detection (PoD) experimental study was carried out in the framework of a Belgian-Quebec/Canada collaborative research project called ThermoPoD. Experiments were implemented on a Carbon Fiber Reinforced Plastic (CFRP) specimen with embedded material simulating delamination. For active infrared thermography, different heating sources (optical or ultrasound), heating forms (pulsed or lock-in), and data processing methods, such as Fourier Transform, Thermal Signal Reconstruction, Wavelet Transform, Differential Absolute Contrast, and Principal Component Thermography are of interest. In the present study, the effects of various data processing methods on PoD curves are compared.
Keywords: CFRP; composite material; data processing; infrared thermography; PoD; reliability

The crack growth behavior of Incoloy 800H under fatigue and dwell-fatigue conditions at elevated temperature - Kim, D. J.; Seo, D. Y.; Tsang, J.; Yang, W. J.; Lee, J. H.; Saari, H.; Seok, C. S. (Journal of Mechanical Science and Technology, 2012)
Fatigue crack growth rate (FCGR) tests with different load ratios and dwell-fatigue crack growth rate (DFCGR) tests with different dwell times were conducted at 750°C for Incoloy 800H. As the load ratio increases from 0.1 to 0.5, the crack growth rate increased and the transition ΔK value from region I to region II (Paris regime) shifted leftward. In DFCGR tests with dwell time of 10 and 30 seconds, the Paris regime started at relatively lower ΔK level and the crack grew much faster than in FCGR tests. However, the crack growth rates between the 10 sec and 30 sec dwell times were relatively similar. The higher crack growth rates in the DFCGR tests compared to FCGR tests was associated with the reduction of the M23C6 precipitates in the vicinity of the advancing crack by the Cr depletion, suggesting the crack propagation in DFCGR conditions was environmentally assisted. The crack growth rate was controlled by trans-granular mode regardless of the dwell time because the dwell time was not enough to cause creep damage.
Keywords: fatigue; dwell-fatigue; crack growth rate; trans-granular; oxidation

The effect of microstructure on creep behavior of a powder metallurgy (PM) beta gamma alloy - Seo, D. Y.; Sawatzky, T.; Saari, H.; Kim, D. J.; Au, P.; Seok, C. S. (Journal of Mechanical Science and Technology, 2012)
Pre-alloyed beta gamma titanium aluminide powder with a nominal composition of TiAl-2Nb-2Mo (G2) is consolidated by hot isostatic pressing. After consolidation, a step cooled heat treatment is performed to homogenize the material and produce a fully lamellar microstructure. Various aging heat treatments are then performed to form interfacial beta phase precipitates along lamellar interfaces. The step cooled heat treatment produces a relatively fine microstructure with an average lamellar grain size of 40 μm. The aging heat treatments generate beta phase precipitates along lamellar grain boundaries as well as along lamellar interfaces, and result in limited lamellar degradation and grain growth. However, coarse intergranular grains consisting of beta and gamma grains form during aging. Constant load tensile creep tests are performed on step cooled heat treated and aged specimens. Primary creep resistance, generally, improves with aging time, even with interfacial precipitation, and the limited lamellar degradation occurs with aging. However, total creep life of aged samples decreases with aging time. The microstructures of the tested specimens are characterized and related to the creep behaviour of the TiAl-2Nb-2Mo alloy in the un-aged and aged conditions.
Keywords: beta gamma TiAl alloy; beta phase; creep; powder metallurgy

Transformative research : definitions, approaches and consequences - Trevors, J. T.; Pollack, Gerald H.; Saier, Milton H.; Masson, Luke (Theory in Biosciences, 2012)
In this perspective a definition of transformative research (TR) is proposed and discussed. We define TR as that which “transforms” or causes a major change in thought patterns concerning an area of scientific endeavor. This type of research is often elusive, requires different approaches and sometimes depends on a bit of luck. TR concerns intangibles such as human intuition, serendipity, unpredictable events, implausible hypotheses, a well-prepared mind and often interpersonal communications. Examples are provided to illustrate how TR may unfold. Contributions it makes to basic and applied humanistic knowledge are highlighted.
Keywords: biosciences; transformative research; future science; humanistic knowledge; intuitive thought; implementation; scholarship; scientifc method; profound discoveries

Cell culture tracking by multivariate analysis of raw LCMS data - Michaud, François-Thomas; Havugimana, Pierre Claver; Duchesne, Carl; Sanschagrin, François; Bernier, Alice; Lévesque, Roger C.; Garnier, Alain (Applied Biochemistry and Biotechnology, 2012)
Liquid chromatography mass spectrometry (LCMS) is a powerful technique that could serve to rapidly characterize cell culture protein expression profile and be used as a process monitoring and control tool. However, this application is often hampered by both the sample proteome and the LCMS signal complexities as well as the variability of this signal. To alleviate this problem, culture samples are usually extensively fractionated and pretreated before being analyzed by top-end instruments. Such an approach precludes LCMS usage for routine on-line or at-line application. In this work, by applying multivariate analysis (MA) directly on raw LCMS signals, we were able to extract relevant information from cell culture samples that were simply lyzed. By using the recombinant adenovirus production process as a model, we were able to follow the accumulation of the three major proteins produced, identified their accumulation dynamics, and draw useful conclusions from these results. The combination of LCMS and MA provides a simple, rapid, and precise means to monitor cell culture.
Keywords: LCMS; multivariate analysis; protein production; virus production; cell culture monitoring

Assessment of titanium aluminide alloys for high-temperature nuclear structural applications - Zhu, Hanliang; Wei, Tao; Carr, David; Harrison, Robert; Edwards, Lyndon; Hoffelner, Wolfgang; Seo, Dongyi; Maruyama, Kouichi (JOM, 2012)
Titanium aluminide (TiAl) alloys exhibit high specific strength, low density, good oxidation, corrosion, and creep resistance at elevated temperatures, making them good candidate materials for aerospace and automotive applications. TiAl alloys also show excellent radiation resistance and low neutron activation, and they can be developed to have various microstructures, allowing different combinations of properties for various extreme environments. Hence, TiAl alloys may be used in advanced nuclear systems as high-temperature structural materials. Moreover, TiAl alloys are good materials to be used for fundamental studies on microstructural effects on irradiation behavior of advanced nuclear structural materials. This article reviews the microstructure, creep, radiation, and oxidation properties of TiAl alloys in comparison with other nuclear structural materials to assess the potential of TiAl alloys as candidate structural materials for future nuclear applications.

Laser cladding of CPM tool steels on hardened H13 hot-work steel for low-cost high-performance automotive tooling - Chen, J.; Xue, L. (JOM, 2012)
This paper summarizes our research on laser cladding of high-vanadium CPM® tool steels (3V, 9V, and 15V) onto the surfaces of low-cost hardened H13 hot-work tool steel to substantially enhance resistance against abrasive wear. The results provide great potential for fabricating high-performance automotive tooling (including molds and dies) at affordable cost. The microstructure and hardness development of the laser-clad tool steels so obtained are presented as well.

Biosynthesis of long chain polyunsaturated fatty acids in the marine Ichthyosporean Sphaeroforma arctica - Vrinten, Patricia; Mavraganis, Ioannis; Qiu, Xiao; Senger, Toralf (Lipids, 2012)
Sphaeroforma arctica is a unique, recently discovered marine protist belonging to a group falling close to the yeast/animal border. S. arctica is found in cold environments, and accordingly has a fatty acid composition containing a high proportion of very long chain polyunsaturated fatty acids, including the ω3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA). Two elongases and five desaturases, representing the complete set of enzymes necessary for the synthesis of DHA from oleic acid, were isolated from this species and characterized in yeast. One elongase showed high conversion rates on a wide range of 18 and 20 carbon substrates, and was capable of sequential elongation reactions. The second elongase had a strong preference for the 20-carbon fatty acids EPA and arachidonic acid, with over 80 % of EPA converted to docosapentaenoic acid (DPA) in the heterologous yeast host. The isolation of a Δ8-desaturase, along with the detection of eicosadienoic acid in S. arctica cultures indicated that this species uses the alternate Δ8-pathway for the synthesis of long-chain polyunsaturated fatty acids. S. arctica also carried a Δ4-desaturase that proved to be very active in the production of DHA from DPA. Finally, a long chain acyl-CoA synthetase from S. arctica improved DHA uptake in the heterologous yeast host and led to an improvement in desaturation and elongation efficiencies.
Keywords: Sphaeroforma arctica; Desaturase; Elongase; Very long chain polyunsaturated fatty acids

Failure analysis of cast iron trunk main in Cleveland, Ohio - Rajani, Balvant; Lewandowski, John; Margevicius, Alex (Journal of Failure Analysis and Prevention, 2012)
This article describes the failure analyses of a 30”-diameter cast iron main that failed suddenly at the bell–spigot joint in Cleveland, Ohio in March 2008. The main had been operating largely without problems since its installation in 1880. The failure was analyzed using three models developed previously, each of which considered a specific failure mechanism candidate, namely (a) operational load or static analysis, (b) joint failure due to ground movement (settlement), and (c) fatigue failure. Operational load analysis clearly showed that while the factor of safety was significantly reduced in the presence of a concrete vault installed in 2002 just above the pipe, the margin of safety was still sufficient for the main to have performed safely. Ground movement analysis of the jointed pipe showed that the construction of the concrete vault above the joint of the 30”-cast iron main subjected the joint to rotation, which might have ultimately cracked the bell leading to failure. Under this circumstance, two failure scenarios are possible: namely, (a) additional rotation was large enough to cause the bell to split, or (b) additional rotation was sufficient to induce a minor crack in the bell but fatigue (repeated) loading caused the crack to grow over time until the combination of crack length and loading was sufficient to cause the bell to eventually split. The color differences along the fracture surfaces indicated that the fracture occurred in two distinct stages. This observation suggests that the second scenario is more plausible than the first.
Keywords: Cast iron mains; Failure analysis; Failure mechanism; Bell–spigot joint

Influence of thermal cycle frequency on the TGO growth and cracking behaviors of an APS-TBC - Chen, W. R.; Wu, X.; Dudzinski, D. (Journal of Thermal Spray Technology, 2012)
The durability of thermal barrier coatings (TBCs) is controlled by fracture near the interface between the ceramic topcoat and the metallic bond coat, where a layer of thermally grown oxide (TGO) forms during service exposure. In the present work, the inﬂuence of thermal cycle frequency on the oxidation performance, in terms of TGO growth and cracking behavior, of an air-plasma-sprayed (APS) Co-32Ni-21Cr-8Al-0.5Y (wt.%) bond coat was studied. The results show that while TGO growth exhibited an initial parabolic growth behavior followed by an accelerated growth stage, higher cycle frequency resulted in a faster TGO growth and a higher crack propagation rate. It is found that a power-law relationship exists between the maximum crack length and the TGO thickness, which is independent of the cycle frequency. This relationship may warrant a TBC life prediction methodology based on the maximum crack length criterion.
Keywords: cracking, holding time, TBC, TGO growth, thermal cycling

Effect of pulsed laser ablation and continuous laser heating on the adhesion and cohesion of cold sprayed Ti-6Al-4V coatings - Perton, M.; Costil, S.; Wong, W.; Poirier, D.; Irissou, E.; Legoux, J.-G.; Blouin, A.; Yue, S. (Journal of Thermal Spray Technology, 2012)
The individual and cumulative effects of in situ pulsed laser ablation and continuous laser pre-heating on adhesion and cohesion strength of cold sprayed Ti-6Al-4V coatings are investigated. Laser beams were coupled to a cold spray gun in order to ablate and pre-heat the substrate surface a few milliseconds prior to the impact of the spray particles. Cohesion and adhesion strength were evaluated by scratch test, standard ASTM C633 pull test and laser shock (LASAT) technique. The effects of laser ablation before and during cold spray operations were investigated. Results demonstrate that laser ablation of the substrate before cold spraying led to a smooth surface which improved adhesion strength. However, when laser ablation was maintained throughout the cold spray process, i.e., in between the coating layers, a reduction of cohesion and adhesion was observed. These negative effects were circumvented when laser ablation and laser pre-heating were combined.
Keywords: adhesion strength; cold spray; continuous laser pre-heating; gas dynamic spray; kinetic spray; LASAT; pulsed laser ablation; surface preparation; Ti-6Al-4V

Optimization of plasma spray process using statistical methods - Gao, F.; Huang, X.; Liu, R.; Yang, Q. (Journal of Thermal Spray Technology, 2012)
The microstructure features of coatings produced by a plasma spray process are affected significantly by the process parameters such as powder size, spray gun nozzle size, total plasma gas flow, ratio of H2 + N2 over total gas flow, and so on. This article presents a study of the effects of these parameters on the microstructure (porosity, formation of crack, unmelted particle and oxide phase) of NiCrAlY coatings deposited by the Mettech Axial III™ System. A Taguchi array is used to design the spraying process parameters. The results of the microstructure evaluation are used to generate regression equations for the prediction of coating microstructure based on process parameters. The results predicted from the regression equations are in good agreement with the experimental results according to a confidence level of 0.95. Among the parameters examined, the powder size and the ratio of H2 + N2 over total gas flow rate are the most significant parameters affecting the occurrence of crack, porosity, unmelted particle and oxide. Within the range of the designed process parameters, lower powder size and higher ratio of H2 + N2 over total gas flow rate lead to less cracks, pores, unmelted particles but more oxides. Nozzle size has marginal influence on oxides which increase with nozzle size. Gas flow rate has no direct influence on any coating feature evaluated with the range of variation.
Keywords: axial injection; crack; NiCrAlY coating; oxide; plasma spray; porosity; process optimization; regression equation; Taguchi method; unmelted particle

Development of the process index for NiCrAlY coatings with the Mettech Axial III™ System - Gao, Feng; Yang, Qi; Huang, Xiao; Liu, Rong (Journal of Materials Engineering and Performance, 2012)
NiCrAlY coatings were deposited using the Mettech Axial III™ plasma spray system. The microstructural features of the coatings, such as the porosity, crack, un-melted particle, and oxide content, were analyzed to investigate the effects of the spray process parameters on these features. Two Taguchi arrays were used to examine the effects of the spray process parameters such as powder size, ratio of (H2 + N2) gas flow over total gas flow, current, spray-gun nozzle size, and spray distance, on the microstructural features of the coatings. The results from statistical analysis are used to create regression equations to predict the microstructural features of the coatings. In the regression equations, a process index (PI) is used as a complex variable incorporating a number of process parameters. The results from an additional set of experiments are used to verify the validity of the regression equations. It has been demonstrated that the equations correlate well with the results from the subsequent set of experiments. It is concluded from this study that the PI can be used to categorize coating qualities with respect to the extent of crack, porosity, unmelted particle, and oxide content in the coating. These equations can also serve as an initial step in developing process parameters by means of the Mettech Axial III™ System.
Keywords: cracks; Mettech Axial III; oxides; pores; process index; regression equations; spray parameters; Taguchi arrays; unmelted particles

A true-stress creep model based on deformation mechanisms for polycrystalline materials - Wu, Xijia; Williams, Steve; Gong, Diguang (Journal of Materials Engineering and Performance, 2012)
A true-stress creep model has been developed based on well-recognized deformation mechanisms, i.e., dislocation glide, dislocation climb, and grain boundary sliding. The model provides a physics-based description of the entire creep deformation process with regards to the strain-time history (primary, secondary, and tertiary creep), rupture strain and lifetime, which finds good agreement with experimental observations for Waspaloy. A deformation-mechanism map is constructed for Waspaloy, and a creep failure criterion is defined by the dominant deformation mechanisms leading to intergranular/transgranular fracture. Thus, the model is a self-consistent tool for creep life prediction.
Keywords: creep; creep life prediction; deformation mechanism

Effect of Mn, Si, and cooling rate on the formation of iron-rich intermetallics in 206 Al-Cu cast alloys - Liu, K.; Cao, X.; Chen, X.-G. (Metallurgical and Materials Transactions B, 2012)
The solidification structures of commercial 206 Al-Cu cast alloys with 0.15 pct Fe have been studied using thermal analysis (TA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and electron backscattered diffraction (EBSD). The EBSD results have shown that there are two iron-rich intermetallics: Chinese script α-Fe and platelet-like β-Fe. The addition of either Mn or Si has helped to promote the formation of α-Fe and hinder the precipitate of β-Fe. The combined addition of both Mn and Si is even more effective than the individual addition of either Mn or Si. The full solidification sequence of the 206 cast alloy has been established. The volume percent and formation temperature increase for α-Fe but decrease for β-Fe with increasing cooling rate. The platelet β-Fe can be effectively suppressed in 206 cast alloys by controlling the alloy chemistry and cooling rate. A casting process map is proposed to correlate the Mn and Si contents with cooling rates for the 206 cast alloys.

Effect of postweld heat treatment on microstructure, hardness, and tensile properties of laser-welded Ti-6Al-4V - Kabir, Abu Syed H.; Cao, Xinjin; Gholipour, Javad; Wanjara, Priti; Cuddy, Jonathan; Birur, Anand; Medraj, Mamoun (Metallurgical and Materials Transactions A, 2012)
The effects of postweld heat treatment (PWHT) on 3.2-mm- and 5.1-mm-thick Ti-6Al-4V butt joints welded using a continuous wave (CW) 4-kW Nd:YAG laser welding machine were investigated in terms of microstructural transformations, welding defects, and hardness, as well as global and local tensile properties. Two postweld heat treatments, i.e., stress-relief annealing (SRA) and solution heat treatment followed by aging (STA), were performed and the weld qualities were compared with the as-welded condition. A digital image correlation technique was used to determine the global tensile behavior for the transverse welding samples. The local tensile properties including yield strength and maximum strain were determined, for the first time, for the laser-welded Ti-6Al-4V. The mechanical properties, including hardness and the global and local tensile properties, were correlated to the microstructure and defects in the as-welded, SRA, and STA conditions.

A new iron-rich intermetallic-Al m Fe phase in Al-4.6Cu-0.5Fe cast alloy - Liu, K.; Cao, X.; Chen, X.-G. (Metallurgical and Materials Transactions A, 2012)
A new iron-rich intermetallic, Al m Fe, is observed, for the first time, in the important A206 (Al-4.6Cu-0.5Fe) cast alloy and identified using electron backscattered diffraction (EBSD) and a transmission electron microscope (TEM). Results show that Chinese script Al m Fe can precipitate as the dominant iron-rich intermetallic at high iron content (0.5 wt pct) and low cooling rate (0.2 K/s). EBSD and TEM results confirmed that Al m Fe has body-centered-tetragonal structure with an average m of approximately 4.2.

Electronic and optical properties of semiconductor and graphene quantum dots - Sheng, Wei-dong; Korkusinski, Marek; Güçlü, Alev Devrim; Zielinski, Michal; Potasz, Pawel; Kadantsev, Eugene S.; Voznyy, Oleksandr; Hawrylak, Pawel (Frontiers of Physics, 2012)
Our recent work on the electronic and optical properties of semiconductor and graphene quantum dots is reviewed. For strained self-assembled InAs quantum dots on GaAs or InP substrate atomic positions and strain distribution are described using valence-force field approach and continuous elasticity theory. The strain is coupled with the effective mass, k · p, effective bond-orbital and atomistic tight-binding models for the description of the conduction and valence band states. The single-particle states are used as input to the calculation of optical properties, with electron-electron interactions included via configuration interaction (CI) method. This methodology is used to describe multiexciton complexes in quantum dot lasers, and in particular the hidden symmetry as the underlying principle of multiexciton energy levels, manipulating emission from biexcitons for entangled photon pairs, and optical control and detection of electron spins using gates. The self-assembled quantum dots are compared with graphene quantum dots, one carbon atom-thick nanostructures. It is shown that the control of size, shape and character of the edge of graphene dots allows to manipulate simultaneously the electronic, optical, and magnetic properties in a single material system.
Keywords: quantum dots; electronic structure; multiexciton; graphene; magnetis

Conversion of lignin to aromatic-based chemicals (L-chems) and biofuels (L-fuels) - Beauchet, R.; Monteil-Rivera, F.; Lavoie, J. M. (Bioresource Technology, 2012)
Conversion of lignin into chemicals and biofuels was performed using the commercial Kraft lignin, Indulin AT. Lignin was depolymerised in an aqueous alkaline solution using a continuous ﬂow reactor generating four fractions. First is the gas fraction (mainly CO₂), the second includes methanol, acetic acid and formic acid, thus deﬁned as small organic compounds and third one (up to 19.1 wt.% of lignin) is mostly composed of aromatic monomers. The fourth fraction (45–70 wt.%) contains oligomers (polyaromatic molecules) and modiﬁed lignin. Pyrocatechol was the most abundant product at high severities (315°C) with selectivity up to 25.8%. ³¹P NMR showed the loss of almost all aliphatic OH groups and apparition of catechol groups during depolymerisation.
Keywords: Lignin; depolymerisation; monomers; oligomers; biofuel

Glutathione, glutathione S-transferase, and glutathione conjugates, complementary markers of oxidative stress in aquatic biota - Hellou, Jocelyne; Ross, Neil W.; Moon, Thomas W. (Environmental Science and Pollution Research, 2012)
Contaminants are ubiquitous in the environment and their impacts are of increasing concern due to human population expansion and the generation of deleterious effects in aquatic species. Oxidative stress can result from the presence of persistent organic pollutants, metals, pesticides, toxins, pharmaceuticals, and nanomaterials, as well as changes in temperature or oxygen in water, the examined species, with differences in age, sex, or reproductive cycle of an individual. The antioxidant role of glutathione (GSH), accompanied by the formation of its disulfide dimer, GSSG, and metabolites in response to chemical stress, are highlighted in this review along with, to some extent, that of glutathione S-transferase (GST). The available literature concerning the use and analysis of these markers will be discussed, focusing on studies of aquatic organisms. The inclusion of GST within the suite of biomarkers used to assess the effects of xenobiotics is recommended to complement that of lipid peroxidation and mixed function oxygenation. Combining the analysis of GSH, GSSG, and conjugates would be beneficial in pinpointing the role of contaminants within the plethora of causes that could lead to the toxic effects of reactive oxygen species.
Keywords: antioxidants; oxidative stress; conjugates; metabolites; glutathione; review; analyses; integration of biomarkers

Probing inhibitory effects of nanocrystalline cellulose: inhibition versus surface charge - Male, Keith B.; Leung, C. W.; Montes, Johnny; Kamen, Amine; Luong, John H. T. (Nanoscale, 2012)
NCC derived from different biomass sources was probed for its plausible cytotoxicity by electric cell-substrate impedance sensing (ECIS). Two different cell lines, Spodoptera frugiperda Sƒ9 insect cells and Chinese hamster lung fibroblast V79, were exposed to NCC and their spreading and viability were monitored and quantified by ECIS. Based on the 50%-inhibition concentration (ECIS₅₀), none of the NCC produced was judged to have any significant cytotoxicity on these two cell lines. However, NCC derived from flax exhibited the most pronounced inhibition on Sƒ9 compared to hemp and celluslose powder. NCCs from flax and hemp pre-treated with pectate lyase were also less inhibitory than NCCs prepared from untreated flax and hemp. Results also suggested a correlation between the inhibitory effect and the carboxylic acid contents on the NCC.

Green strategy guided by Raman spectroscopy for the synthesis of ammonium carboxylated nanocrystalline cellulose and the recovery of byproducts - Lam, Edmond; Leung, Alfred C. W.; Liu, Yali; Majid, Ehsan; Hrapovic, Sabahudin; Male, Keith B.; Luong, John H. T. (ACS Sustainable Chemistry & Engineering, 2012)
A one-pot green procedure for the treatment of cellulosic biomass with ammonium persulfate (APS) was developed for the synthesis of highly crystalline carboxylated nanocrystalline cellulose (NCC–COOH), an emerging nanomaterial with a plethora of diversified applications. Raman spectroscopy proved applicable for monitoring the fate of APS and its two byproducts during the production of NCC–COOH from microcrystalline cellulose (MCC). The two main byproducts were then identified and quantified as ammonium sulfate (AS) and H₂SO₄ with the latter accounted for 60% of the total sulfate ions in solution. On the basis of such findings, one-step neutralization of H₂SO₄ and NCC with NH₄OH immediately after reaction was implemented for the formation of additional AS, followed by its quantitative recovery by precipitation. This was a very effective and critical step in waste stream management and cost reduction for the large scale production of NCC. In addition, the process resulted in highly crystalline NCC with COO⁻NH₄⁺ groups, a nanomaterial with improved dispersion and thermal characteristics over NCC with COOH and COO⁻Na⁺ groups.
Keywords: Nanocrystalline cellulose; Raman spectroscopy; persulfate; sulfate; sulfuric acid

Integration of deep transcript and targeted metabolite profiles for eight cultivars of opium poppy - Desgagné-Penix, Isabel; Farrow, Scott C.; Cram, Dustin; Nowak, Jacek; Facchini, Peter J. (Plant Molecular Biology, 2012)
Recent advances in DNA sequencing technology and analytical mass spectrometry are providing unprecedented opportunities to develop the functional genomics resources required to investigate complex biological processes in non-model plants. Opium poppy produces a wide variety of benzylisoquinoline alkaloids (BIAs), including the pharmaceutical compounds codeine, morphine, noscapine and papaverine. A functional genomics platform to identify novel BIA biosynthetic and regulatory genes in opium poppy has been established based on the differential metabolite profile of eight selected cultivars. Stem cDNA libraries from each of the eight opium poppy cultivars were subjected to 454 pyrosequencing and searchable expressed sequence tag databases were created from the assembled reads. These deep and integrated metabolite and transcript databases provide a nearly complete representation of the genetic and metabolic variances responsible for the differential occurrence of specific BIAs in each cultivar as demonstrated using the biochemically well characterized pathway from tyrosine to morphine. Similar correlations between the occurrence of specific transcripts and alkaloids effectively reveals candidate genes encoding uncharacterized biosynthetic enzymes as shown using cytochromes P450 potentially involved in the formation of papaverine and noscapine.
Keywords: 454 Pyrosequencing; Benzylisoquinoline alkaloid; Opium poppy; Metabolite proﬁling; Transcriptomic

A molecular and proteomic investigation of proteins rapidly released from triticale pollen upon hydration - Zaidi, Mohsin A.; O’Leary, Stephen; Wu, Shaobo; Gleddie, Steve; Eudes, François; Laroche, André; Robert, Laurian S. (Plant Molecular Biology, 2012)
Analysis of Triticale (×Triticosecale Wittmack cv. AC Alta) mature pollen proteins quickly released upon hydration was performed using two-dimensional gel electrophoresis followed by mass spectrometry. A total of 17 distinct protein families were identified and these included expansins, profilins, and various enzymes, many of which are pollen allergens. The corresponding genes were obtained and expression studies revealed that the majority of these genes were only expressed in developing anthers and pollen. Some genes including glucanase, glutathione peroxidase, glutaredoxin, and a profilin were found to be widely expressed in different reproductive and vegetative tissues. Group 11 pollen allergens, polygalacturonase, and actin depolymerizing factor were characterized for the first time in the Triticeae. This study represents a distinctive combination of proteomic and molecular analyses of the major cereal pollen proteins released upon hydration and therefore at the forefront of pollen-stigma interactions.
Keywords: Triticale; pollen; tapetum; allergens; proteome; pollen hydration

Noninvasive cell-based impedance spectroscopy for real-time probing inhibitory effects of Graphene derivatives - Male, Keith B.; Lam, Edmond; Montes, Johnny; Luong, John H. T. (ACS Applied Materials & Interfaces, 2012)
Three water-dispersible graphene derivatives, graphene oxide (GO), sulfonated graphene oxide (SGO), and sulfonated graphene (SG), were prepared and probed for their plausible cytotoxicity by non-invasive electric cell-substrate impedance sensing (ECIS). With Spodoptera frugiperda Sƒ9 insect cells adhered on gold microelectrodes as an active interface, it is feasible to monitor changes in impedance upon exposure to different graphene derivatives. Sƒ9 insect cells were then exposed to different concentrations of graphene derivatives and their spreading and viability were monitored and quantified by ECIS in real-time. On the basis of the 50% inhibition concentration (ECIS₅₀), none of the graphene derivatives were judged to have any significant cytotoxicity with respect to the chosen cell line as the ECIS₅₀ values were all above 100 μg/mL. However, all graphene derivatives exhibited inhibitory effects on the Sƒ9 response at the cell spreading level with the following order: SG (ECIS₅₀ = 121 ± 8 μg/mL), SGO (ECIS₅₀ = 151 ± 9 μg/mL), and GO (ECIS₅₀ = 232 ± 27 μg/mL), reflecting differences observed in their ζ-potential and surface area. The presence of phenyl sulfonyl groups in SGO and SG improves their aqueous dispersity which enables these materials to have a greater inhibitory effect on Sƒ9 insect cells in comparison to GO. Such results were corroborated well with the cell count and viability by the Trypan Blue exclusion assay.
Keywords: Graphene; cytotoxicity; electric cell-substrate impedance sensing; insect cells; viability assay

Quantiﬁcation of superparamagnetic iron oxide with large dynamic range using TurboSPI - Rioux, James A.; Brewer, Kimberly D.; Beyea, Steven D.; Bowen, Chris V. (Journal of Magnetic Resonance, 2012)
This work proposes the use of TurboSPI, a multi-echo single point imaging sequence, for the quantiﬁcation of labeled cells containing moderate to high concentrations of iron oxide contrast agent. At each kspace location, TurboSPI acquires several hundred time points during a spin echo, permitting reliable relaxation rate mapping of large-R*₂ materials. An automatic calibration routine optimizes image quality by promoting coherent alignment of spin and stimulated echoes throughout the multi-echo train, and this calibration is sufﬁciently robust for in vivo applications. In vitro relaxation rate measurements of SPIO-loaded cervical cancer cells exhibit behavior consistent with theoretical predictions of the static dephasing regime in the spin echo case; the relaxivity measured with TurboSPI was 10.47 ± 2.3 s⁻¹/mG, comparable to the theoretical value of 10.78 s⁻¹/mG. Similar measurements of micron-sized iron oxide particles (0.96 µm and 1.63 µm diameter) show a reduced relaxivity of 8.06 ± 0.68 s⁻¹/mG and 7.13 ± 0.31 s⁻¹/mG respectively, indicating that the static dephasing criterion was not met. Nonetheless, accurate quantiﬁcation of such particles is demonstrated up to R*₂ = 900 s⁻¹, with a potentially higher upper limit for loaded cells having a more favorable R'₂:R₂ ratio. Based on the cells used in this study, reliable quantiﬁcation of cells loaded with 10 pg of iron per cell should be possible up to a density of 27 million cells/mL. Such quantiﬁcation will be of crucial importance to the development of longitudinal monitoring for cellular therapy and other procedures using iron-labeled cells
Keywords: Quantification; relaxometry; single point imaging; iron oxide; static dephasing

Magnetic resonance microscopy for assessment of morphological changes in hydrating hydroxypropylmethyl cellulose matrix tablets in situ - Kulinowski, Piotr; Młynarczyk, Anna; Dorożyński, Przemysław; Jasiński, Krzysztof; Gruwel, Marco L. H.; Tomanek, Bogusław; Węglarz, Władysław P. (Pharmaceutical Research, 2012)
Purpose To resolve contradictions found in morphology of hydrating hydroxypropylmethyl cellulose (HPMC) matrix as studied using Magnetic Resonance Imaging (MRI) techniques. Until now, two approaches were used in the literature: either two or three regions that differ in physicochemical properties were identified. Methods Multiparametric, spatially and temporally resolved T2 MR relaxometry in situ was applied to study the hydration progress in HPMC matrix tablets using a 11.7 T MRI system. Two spin-echo based pulse sequences—one of them designed to specifically study short T2 signals—were used. Results Two components in the T2 decay envelope were estimated and spatial distributions of their parameters, i.e. amplitudes and T2 values, were obtained. Based on the data, five different regions and their temporal evolution were identified: dry glassy, hydrated solid like, two interface layers and gel layer. The regions were found to be separated by four evolving fronts identified as penetration, full hydration, total gelification and apparent erosion. Conclusions The MRI results showed morphological details of the hydrating HPMC matrices matching compound theoretical models. The proposed method will allow for adequate evaluation of controlled release polymeric matrix systems loaded with drug substances of different solubility.
Keywords: controlled release; hydroxypropylmethyl cellulose (HPMC); pharmaceutical magnetic resonance imaging (MRI); swellable matrix tablets; T2 magnetic resonance relaxometry

Cyclic oxidation and interdiffusion behaviour of a NiCrAlY coated powder metallurgy beta gamma TiAl–2Nb–2Mo alloy - Kim, D. J.; Huang, X.; Seo, D. Y.; Kim, Y.-W. (Oxidation of Metals, 2012)
A new beta-gamma TiAl–2Nb–2Mo alloy was synthesized using powder metallurgy process and coated with NiCrAlY by air plasma spray technique. The cyclic oxidation behaviour of the coated beta-gamma alloy was investigated at 1,000 °C for up to 800 cycles. During cyclic oxidation testing, titanium nitride layer was found to form at the interface between NiCrAlY and TiAl–2Nb–2Mo and the thickness of the titanium nitride layer increased with oxidation cycles. Additionally, outward diffusion of Ti from the beta-gamma substrate caused the formation of titanium oxides on the coating surface after 630 cycles. Inward diffusion of Ni from NiCrAlY led to the formation of an inner diffusion zone containing NiAlTi and mixture of NiAlTi + TiAl. Due to the spallation of coating scales on the circumferential surface of the button specimens, weight loss was observed after 120 cycles; however, NiCrAlY coating on both top and bottom surfaces of the specimens remained in contact with the substrate for up to 800 cycles. Due to the inward and outward diffusion of various elements, one third of the NiCrAlY coating was consumed after 800 cycles, which suggests the need for diffusion barrier coating at the interface between the NiCrAlY coating and the TiAl–2Nb–2Mo alloy.
Keywords: beta gamma alloy; NiCrAlY coating; powder metallurgy; cyclic oxidation

Picosecond all-optical switching using nonlinear Mach–Zehnder with silicon subwavelength grating and photonic wire arms - Glesk, I.; Bock, P. J.; Cheben, P.; Schmid, J. H.; Lapointe, J.; Janz, S. (Optical and Quantum Electronics, 2012)
We investigate the picosecond switching capabilities of a planar waveguide interferometric photonic device when used for all-optical wavelength conversion of one picosecond pulses. Our device comprises a subwavelength grating waveguide arm and a photonic wire waveguide arm in a Mach–Zehnder configuration, fabricated on the silicon-on-insulator material platform. No detrimental effects of pulse broadening for transient pulses were observed.
Keywords: integrated picosecond all-optical switch; diffraction gratings; subwavelength structures; all-optical switching device

Development of a Fourier-transform waveguide spectrometer for space applications - Florjańczyk, Mirosław; Alonso-Ramos, Carlos; Bock, Przemek; Bogdanov, Alexei; Cheben, Pavel; Molina-Fernández, Íñigo; Janz, Siegfried; Lamontagne, Boris; Ortega-Moñux, Alejandro; Scott, Alan; Sinclair, Kenneth; Solheim, Brian; et al. (Optical and Quantum Electronics, 2012)
We describe the development of a waveguide Fourier-transform spectrometer for space-borne high-resolution sensing. A prototype device is designed to monitor the water vapor absorption band near 1,364 nm with a resolution of 0.05 nm. It has no moving parts and is based on a unique concept of arrayed interferometers implemented in silicon-on-insulator planar waveguide chip. The optical input is formed by many independent waveguides, providing a significantly increased light gathering capability (étendue) compared to single-waveguide input configurations. Enhancements of the spectrometer capabilities are achieved by stacking planar waveguide layers and by using surface gratings to couple light into the waveguides.
Keywords: spectrometers and spectroscopic instrumentation; planar waveguides; Fourier transform spectroscopy

Grating couplers for thick SOI rib waveguides - Alonso-Ramos, C.; Ortega-Moñux, A.; Molina-Fernández, I.; Cheben, P.; Zavargo-Peche, L.; Halir, R.; Janz, S.; Xu, D.-X.; Kim, N.; Lamontagne, B. (Optical and Quantum Electronics, 2012)
The use of grating couplers in high index contrast waveguides like silicon on insulator (SOI) offers several advantages over other coupling approaches, including better alignment tolerances and allowing for wafer-scale testing. The grating couplers were developed for nanometric SOI waveguides (Si-wires), and recently also for micrometric rib waveguides. In this paper we review our work in fiber-to-chip grating couplers for thick SOI rib waveguides, where a coupling efficiency of −2.2 dB was demonstrated experimentally. We also discuss the use of grating couplers to improve optical throughput (étendue) of a planar waveguide Fourier-Transform (FT) spectrometer implemented in thick rib waveguides.
Keywords: grating coupler; planar waveguide; rib waveguide; SOI; FT spectrometer

Single etch grating couplers for mass fabrication with DUV lithography - Halir, R.; Zavargo-Peche, L.; Xu, D.-X.; Cheben, P.; Ma, R.; Schmid, J. H.; Janz, S.; Densmore, A.; Ortega-Moñux, A.; Molina-Fernández, Í.; Fournier, M.; Fédeli, J.-M. (Optical and Quantum Electronics, 2012)
Surface grating couplers enable efficient coupling of light between optical fibers and planar waveguide circuits. While traditional grating designs require two etch steps for efficient coupling to silicon-on-insulator waveguides, recently proposed subwavelength structured gratings can achieve the same coupling efficiencies with a single etch step, thereby significantly reducing fabrication complexity. Here we demonstrate that such couplers can be fabricated on a large scale with ultra-violet lithography, achieving a 5 dB coupling efficiency at 1,550 nm. Through both simulations and experiments we give physical insight on how pattern fidelity impacts the performance of these couplers, and propose strategies to deal with inevitable process variations.
Keywords: fiber-to-chip grating coupler; deep ultraviolet lithography; single etch process

Fast light-emitting silicon-germanium nanostructures for optical interconnects - Lockwood, D. J.; Tsybeskov, L. (Optical and Quantum Electronics, 2012)
Epitaxially-grown Si/SiGe quantum dot complexes produce efﬁcient photoluminescence and electroluminescence in the desired spectral range of 1.3–1.6µm. The latest progress in our understanding of the physics of carrier recombination in Si/SiGe nanostructures is reviewed, and a new route toward CMOS compatible light emitters is proposed.
Keywords: silicon; germanium; dots; photoluminescence; electroluminescence

A model for deployment of a freefall lifeboat from a moving ramp into waves - Raman-Nair, W.; White, M. (Multibody System Dynamics, 2012)
The equations of motion of a freefall lifeboat are formulated using Kane’s method. Deployment from a moving ramp is assumed to occur in a known plane and a 2D model suffices. A segmented approach is used to model ramp contact. A separate 3D model is presented for the water entry phase. The hydrodynamic loads at water entry are also modeled using a segmented approach. The equations are solved numerically using a standard Runge–Kutta MATLAB routine.
Keywords: freefall lifeboat; moving ramp; water entry; Kane`s equation

Introgression of Brassica rapa subsp. sylvestris blackleg resistance into B. napus - Yu, F.; Lydiate, D. J.; Gugel, R. K.; Sharpe, A. G.; Rimmer, S. R. (Molecular Breeding, 2012)
Blackleg, caused by Leptosphaeria maculans, is one of the most economically important diseases of Brassica napus worldwide. Two blackleg resistance genes, LepR1 and LepR2, from B. rapa subsp. sylvestris (BRS) were previously identified. To transfer LepR1 and LepR2 from BRS into B. napus, interspecific hybridizations were made between the two species to form allotriploids. Analysis of microsatellite markers in two BC1 populations, WT3BC1 and WT4BC1, indicated that segregation fit a 1:1 ratio for BRS and non-BRS alleles on the A-genome linkage groups N2 and N10, the locations of LepR1 and LepR2, respectively. However, recombination frequencies in the allotriploid BC1 populations were at least twice those in the amphidiploid. The number of C-genome chromosomes in the BC1 plants was determined through marker analysis, which indicated averages of 5.9 and 5.0 per plant in the WT3BC1 and WT4BC1 populations, respectively. Two L. maculans isolates, WA51 and pl87-41, were used to differentiate plants carrying resistance genes LepR1 and LepR2. Surprisingly, only 4.0 and 16.6 % of the plants were resistant to isolates WA51 and pl87-41, respectively, in the WT3BC1 population, while 17.9 and 33.3 % of the plants were resistant to these isolates, respectively, in the WT4BC1 population. No association of resistance to isolate WA51 or pl87-41 with linkage group N2 or N10 was found. Based on cotyledon resistance and marker-assisted selection (MAS), BC1 plant WT4-4, which carried a resistance gene similar to LepR1, herein designated LepR1′, and BC2S1 plant WT3-21-25-9, which carried LepR2′, were identified. These plants were successively backcrossed with B. napus and MAS was employed in each generation to reduce non-resistance alleles associated with the BRS genome and to recover the full complement of C-genome chromosomes, resulting in highly blackleg-resistant B. napus lines.
Keywords: Brassica napus; Brassica rapa; Leptosphaeria maculans; molecular mapping; marker-assisted selectio

The sorption behaviors in PLLA-CO2 system and its effect on foam morphology - Liao, Xia; Nawaby, Arghavan V. (Journal of Polymer Research, 2012)
The sorption behavior, physical properties, and foam morphologies in poly(L-lactic acid) (PLLA)-CO2 system were studied in this paper. The solubility and diffusion coefficient of CO2 in PLLA in the range of 0 °C to 45 °C and pressure up to 5.5 MPa were investigated. The diffusion coefficients were analyzed to determine the plasticization glass transition temperature (T g ) of the PLLA-CO2 systems. The data of T g s of PLLA at various CO2 pressures demonstrated that PLLA-CO2 system exhibited a retrograde vitrification behavior, which has never been reported on semi-crystalline polymer-gas system by systematic measurement of solubility data. The sorption curves of PLLA at certain temperatures and pressures exhibited a characteristic keen which indicated the rejection of CO2 from the polymer matrix due to CO2-induced crystallization. The fundamental understanding of PLLA-CO2 interactions was utilized to control the CO2 solubility and crystallinity in PLLA thus the physical properties, in order to develop various unique foam structures.
Keywords: Poly(L-lactic acid) (PLLA); CO2; Retrograde behavior; crystallization; foam morphology

Resolution-by-proxy : a simple measure for assessing and comparing the overall quality of NMR protein structures - Berjanskii, Mark; Zhou, Jianjun; Liang, Yongjie; Lin, Guohui; Wishart, David S. (Journal of Biomolecular NMR, 2012)
In protein X-ray crystallography, resolution is often used as a good indicator of structural quality. Diffraction resolution of protein crystals correlates well with the number of X-ray observables that are used in structure generation and, therefore, with protein coordinate errors. In protein NMR, there is no parameter identical to X-ray resolution. Instead, resolution is often used as a synonym of NMR model quality. Resolution of NMR structures is often deduced from ensemble precision, torsion angle normality and number of distance restraints per residue. The lack of common techniques to assess the resolution of X-ray and NMR structures complicates the comparison of structures solved by these two methods. This problem is sometimes approached by calculating “equivalent resolution” from structure quality metrics. However, existing protocols do not offer a comprehensive assessment of protein structure as they calculate equivalent resolution from a relatively small number (<5) of protein parameters. Here, we report a development of a protocol that calculates equivalent resolution from 25 measurable protein features. This new method offers better performance (correlation coefficient of 0.92, mean absolute error of 0.28 Å) than existing predictors of equivalent resolution. Because the method uses coordinate data as a proxy for X-ray diffraction data, we call this measure “Resolution-by-Proxy” or ResProx. We demonstrate that ResProx can be used to identify under-restrained, poorly refined or inaccurate NMR structures, and can discover structural defects that the other equivalent resolution methods cannot detect.
Keywords: protein; structure; quality; NMR; x-ray resolution

Supported and unsupported platinum catalysts prepared by a one-step dry deposition method and their oxygen reduction reactivity in acidic media - Roller, Justin; Neagu, Roberto; Orfino, Frank; Maric, Radenka (Journal of Materials Science, 2012)
The present study examines the physical and electrochemical properties of platinum particles generated by a combustion method for use in oxygen reduction on the cathode side of a proton exchange fuel cell (PEMFC). This method employs a one-step, open-atmosphere, and dry deposition technique called reactive spray deposition technology (RSDT). The objective of this study is to characterize the intrinsic activity of the platinum produced for incorporation into low-loading cathode electrodes in high performing membrane electrode assemblies (MEA). The process allows for independent real-time control of the carbon, platinum, and ionomer ratios in the final electrode. In this research work we examine the oxygen reduction reaction via a rotating disk three electrode set-up to understand the intrinsic activity of the as-sprayed platinum as well as platinum condensed onto a carbon support. The mass and specific activities were measured in a 0.1 M perchloric acid electrolyte under different deposition conditions and loading was verified by atomic emission spectroscopy inductively coupled plasma (AES-ICP). Microscopy results indicate that the platinum particle sizes are 5 nm (σ = 2.8 nm) in diameter while TEM and XRD show that the platinum generated by the process is pure and crystalline without bulk oxides or precursor material present. The initial rotating disk electrode result shows that the RSDT technique is capable of producing catalysts with an oxygen reduction mass activity at 0.9 V of 200 mA/mgPt rotating at 1600 rpm and 30 °C. The electrochemically active surface area approaches 120 m2/g for the platinum, carbon, and ionomer samples and the unsupported sample with only platinum has an active area of 92 m2/g. The rather larger surface area of the unsupported sample exists when the platinum is deposited as a highly porous nanostructured layer that allows for high penetration of reactant.

Precipitation of iron-rich intermetallic phases in Al-4.6Cu-0.5Fe-0.5Mn cast alloy - Liu, K.; Cao, X.; Chen, X.-G. (Journal of Materials Science, 2012)
The solidification of Al-4.6Cu-0.5Fe-0.5Mn (206 type) cast alloy has been studied using Thermal Analysis, Differential Scanning Calorimeter, Scanning Electron Microscopy, Electron Back-Scattered Diffraction (EBSD), and Transmission Electron Microscopy (TEM). It is interesting to note that an iron-rich intermetallic phase, Al3(FeMn), is experimentally observed to be dominantly present in the fully solidified cast structure of the experimental 206 cast alloy, in addition to β-Fe (Al7Cu2(FeMn)/Al7Cu2Fe) phase. Al3(FeMn) phase is formed through a eutectic reaction approximately at 640 °C during solidification, possibly resulting from the phase selection and segregation of Fe in liquid Al. The presence of the Al3(FeMn) phase has been confirmed by both EBSD and TEM. It is also found that both β-Fe and Al6(FeMn) are possible to nucleate on Al3(FeMn), as confirmed by the calculated low planar disregistries. The possible solidification reactions have been established for 206-type cast alloy at 0.5%Fe.

Adhesive surface interactions of cellulose nanocrystals from different sources - Lahiji, Roya R.; Boluk, Yaman; McDermott, Mark (Journal of Materials Science, 2012)
Adhesion plays an important role in the final properties of nanocomposites. This study explored the surface interaction of cellulose nanocrystals (CNCs) and the effect of CNC sources on adhesion between individual CNCs and the Si tip of an AFM cantilever using a force mapping technique called FMap. The adhesion between CNCs and a Si tip from five different sources has been studied: cotton, Whatman filter paper, hemp, softwood chemical kraft pulp, and softwood-dissolving pulp (alistaple). Mica was used as the background substrate to act as an internal standard. This study’s findings suggest that adhesion is not the same for all CNCs. Transmission electron microscopy and atomic force microscopy were used to determine the size and shape of each CNC. The experimental quantitative data showed that adhesion between CNCs and the Si tip has a close correlation with the diameter of the CNCs. X-ray photoelectron spectroscopy confirmed the presence of sulfate groups on the surface of the CNCs and a correlation between adhesion and surface chemistry of the CNCs was observed.

Five new galactolipids from the freshwater microalga Porphyridium aerugineum and their nitric oxide inhibitory activity - Banskota, Arjun H.; Stefanova, Roumiana; Sperker, Sandra; Melanson, Ronald; Osborne, Jane A.; O’Leary, Stephen J. B. (Journal of Applied Phycology, 2012)
Chemical investigation of the freshwater rhodophyte microalga Porphyridium aerugineum led to the isolation of five new galactolipids, namely, (2S)-1-O-eicosapentaenoyl-2-O-arachidonoyl-3-O-β-d-galactopyranosylglycerol (1), (2S)-1-O-eicosapentaenoyl-2-O-linoleoyl-3-O-β-d-galactopyranosylglycerol (2), (2S)-1-O-arachidoyl-2-O-palmitoyl-3-O-(β-d-galactopyranosyl-6-1α-d-galactopyranosyl)-glycerol (6), (2S)-1-O-eicosapentaenoyl-2-O-arachidoyl-3-O-(β-d-galactopyranosyl-6-1α-d-galactopyranosyl)-glycerol (7), and (2S)-1-O-eicosapentaenoyl-2-O-linoleoyl-3-O-(β-d-galactopyranosyl-6-1α-d-galactopyranosyl)-glycerol (8) together with five known galactolipids. The stereo-structures of all new galactolipids were elucidated by spectroscopic analyses and both enzymatic and chemical degradation methods. This is the first report of galactolipids from P. aerugineum. The newly isolated galactolipids showed strong and dose-dependent nitric oxide (NO) inhibitory activity against lipopolysaccharide-induced NO production in RAW264.7 macrophage cells. Both galactolipids 1 and 2 possessed stronger NO inhibitory activity than N G-methyl-l-arginine acetate salt, a well-known NO inhibitor used as a positive control. Further study suggested that these galactolipids inhibit NO production through downregulation of inducible nitric oxide synthase expression.
Keywords: Porphyridium aerugineum; rhodophyta; galactolipid; monogalactosyldiacylglycerol (MGDG); digalactosyldiacylglycerol (DGDG); nitric oxide; inducible nitric oxide synthase

Small molecules containing hetero-bicyclic ring systems compete with UDP-Glc for binding to WaaG glycosyltransferase - Landström, Jens; Persson, Karina; Rademacher, Christoph; Lundborg, Magnus; Wakarchuk, Warren; Peters, Thomas; Widmalm, Göran (Glycoconjugate Journal, 2012)
The α-1,3-glucosyltransferase WaaG is involved in the synthesis of the core region of lipopolysaccharides in E. coli. A fragment-based screening for inhibitors of the WaaG glycosyltrasferase donor site has been performed using NMR spectroscopy. Docking simulations were performed for three of the compounds of the fragment library that had shown binding activity towards WaaG and yielded 3D models for the respective complexes. The three ligands share a hetero-bicyclic ring system as a common structural motif and they compete with UDP-Glc for binding. Interestingly, one of the compounds promoted binding of uridine to WaaG, as seen from STD NMR titrations, suggesting a different binding mode for this ligand. We propose these compounds as scaffolds for the design of selective high-affinity inhibitors of WaaG. Binding of natural substrates, enzymatic activity and donor substrate selectivity were also investigated by NMR spectroscopy. Molecular dynamics simulations of WaaG were carried out with and without bound UDP and revealed structural changes compared to the crystal structure and also variations in flexibility for some amino acid residues between the two WaaG systems studied.
Keywords: glycosyltransferase; inhibitor; NMR; molecular modeling; screening

Fire resistance of wood truss floor assemblies - Sultan, Mohamed A. (Fire Technology, 2012)
This paper presents and discusses the factors that affect the fire resistance performance of lightweight wood truss floor assemblies protected with two layers of Type X gypsum board ceiling finishes. Fifteen full-scale fire resistance floor experiments were conducted using the CAN/ULC S-101 fire resistance standard which is similar to the ASTM E119. Parameters investigated in this study include the effects of insulation installation in floor cavity, insulation type, wood truss spacing, resilient channel installation, resilient channel spacing, wood truss width, wood truss chord orientation, wood truss web type, wood truss connection type and adding concrete topping above the sub-floor. The impact of these parameters on the fire resistance performance of the wood truss floor assemblies is discussed. The fire resistance of wood truss floors appears to be essentially governed by the wood trusses’ spacing for direct application of gypsum board to wood truss framing, insulation type and resilient channel installation and spacing. Other parameters are of secondary importance.
Keywords: wood truss; floor assemblies; fire resistance; insulation; resilient channel; concrete topping

Evaluation of the onset of flashover in room fire experiments - Poulsen, Annemarie; Bwalya, Alex; Jomaas, Grunde (Fire Technology, 2012)
Two series of full scale room fire tests comprising 16 experiments are used for a study of the onset of flashover. The fire loads were varied and represented seven different commercial applications and two non-combustible linings with significantly different thermal inertia were used. The test results showed that by lowering the thermal inertia and thereby lowering the heat loss from the room and at the same time increasing the thermal feedback, a thermal runaway occurred before significant fire spread; but only for objects composed of a mixture of plastic/rubber/textiles and wood/celluloses. In these cases the onset of thermal runaway was found to occur at room temperatures in the range 300°C to 420°C, supporting that the room temperature at the onset of thermal runaway is strongly dependent on the thermal inertia. It also shows that the onset of thermal runaway cannot in all cases implicitly be predicted by the traditional flashover temperature criterion of 500°C to 600°C. For fire loads composed of pure wood/celluloses the onset of flashover occurred about the same time as fire spread irrespectively of linings and at significantly higher room temperatures (725°C). This can be explained by flammability parameters making wood/celluloses less sensitive to thermal feedback.
Keywords: flashover; room fire experiments; thermal runaway; thermal feedback; thermal inertia

Interaction between alkaline earth cations and oxo ligands : a DFT study of the affinity of Mg2+ for carbonyl ligands - Moreira da Costa, Leonardo; Stoyanov, Stanislav R.; Walkimar de M. Carneiro, José (Journal of Molecular Modeling, 2012)
The affinities of Mg2+ for various substituted carbonyl ligands were determined at the DFT (B3LYP/6-31+G(d)) and semi-empirical (PM6) levels of theory. Two sets of carbonyl ligands were studied: monosubstituted [aldehydes R–CHO and RPh–CHO] and homodisubstituted [ketones R2C=O and (RPh)2C=O], where R = NH2, OCH3, OH, CH3, H, F, Cl, Br, CN, or NO2). In the (RPh)2CO case, the R group was bonded to the para position of a phenyl ring. The enthalpies of interaction between the ligands and a pentaaquomagnesium(II) complex were calculated to determine the affinity of each ligand for the Mg2+ cation and to correlate with geometrical and electronic parameters. These parameters exhibited the same trends for all of the ligands studied, showing that the affinity of Mg2+ for electron-donating ligands is higher than its affinity for electron-withdrawing ligands. In the complexes, electron-donating groups increase both the electrostatic and the covalent components of the Mg–ligand interaction. This behavior correlates with the Mg–O(carbonyl) distance and the ligand electron-donor strength.
Keywords: Magnesium cation; Substituent effect; DFT; Interaction enthalpy

GQ1b-seronegative Fisher syndrome: clinical features and new serological markers - Koga, Michiaki; Gilbert, Michel; Takahashi, Masaki; Li, Jianjun; Hirata, Koichi; Kanda, Takashi; Yuki, Nobuhiro (Journal of Neurology, 2012)
IgG anti-GQ1b antibodies are a powerful serological marker for the diagnosis of Fisher syndrome (FS), but little is known regarding serological markers in FS patients that do not have the autoantibodies. The authors analyzed IgG antibodies against gangliosides other than GQ1b, ganglioside complexes, and ganglioside-like lipo-oligosaccharide (LOS) of Campylobacter jejuni isolates from FS patients. We identified 24 (12%) patients with GQ1b-seronegative FS among 207 FS patients who had been referred to our laboratory for anti-ganglioside antibody testing. Patients with GQ1b-seronegative FS were male and had a history of antecedent gastrointestinal illness more frequently than FS patients with IgG anti-GQ1b antibodies. Other clinical features during the illness were not distinguishing for GQ1b-seronegative FS. Four (17%) of 24 patients with GQ1b-seronegative FS had IgG antibodies against single gangliosides such as GM1b, GD1a, or GT1a. Antibodies against GM1 and GT1a complex were detected in four GQ1b-seronegative FS patients, three of whom did not have antibodies against single gangliosides. Mass spectrometry analysis showed that C. jejuni isolates from FS patients had GD1c-, GalNAc-GM1b-, or GalNAc-GD1c-like LOS, and not GQ1b-like LOS, highlighting the utility of examining serum antibodies against these ganglioside mimics in GQ1b-seronegative FS patients. Seven (29%) had IgG antibodies against the LOS from C. jejuni strains expressing GD1c-, GalNAc-GM1b-, or GalNAc-GD1c-like LOS. These findings suggest that IgG antibodies against GM1b, GD1c, GalNAc-GM1b, and ganglioside complexes are serological markers for GQ1b-seronegative Fisher syndrome.
Keywords: Fisher syndrome; Anti-GQ1b antibody; Campylobacter jejuni; Ganglioside complex; Lipooligosaccharide

Superhydrophobic surfaces fabricated by spray-coating micelle solutions of comb copolymers - Cui, Zhe; Ding, Jianfu; Scoles, Ludmila; Wang, Qingjun; Chen, Qingmin (Colloid and Polymer Science, 2012)
A series of comb copolymers (poly(arylene alkylene ether) (FPAE)-polystyrene (PS)) with a highly fluorinated FPAE main chain and narrow dispersed PS-grafted chains have been prepared. They are used to prepare micelle solutions in methanol/acetone (M/A) mixed solvents which are good for the FPAE main chains and poor for the PS-grafted chains. In these solutions, the PS-grafted chains form the cores and the FPAE main chains form the corona layers of micelle particles. Uniform micelle particles are achieved because of the narrow molecular weight dispersion of the PS chain length. The micelle solutions are spray-coated onto glass substrates to fabricate hydrophobic surfaces. It is found that the stability of the micelle particles increases with the length of the PS-grafted chains, which further influences the morphology and hydrophobicity of the spray-coated films. The effects of the M/A ratio and the copolymer concentration on the morphology and hydrophobicity of the coating surfaces are also studied. The results prove that a binary nano/microsurface structure is important to achieve a superhydrophobic surface with a low contact angle hysteresis. This binary structure is formed from conglomeration of micelle particles by spray coating the micelle solutions. The best sample reported in this paper has a static contact angle of 163° and a sliding angle of 5.9°. This fabrication procedure is facile, less time consuming, and easily applicable for large-scale surface treatment.
Keywords: Superhydrophobic; Micelle particles; Comb copolymer; Fluorinated polyether; Polystyrene

Nanoscale laser-induced forward transfer through patterned Cr films - Sametoglu, V.; Sauer, V.; Tsui, Y. Y. (Applied Physics A, 2012)
The resolution enhancement of laser-induced forward transfer (LIFT) is investigated through the pre-patterning of Cr on the donor substrate. 85 nm dots are first patterned on a microscope slide, and an 800 nm wavelength and 130 fs pulse laser with a beam waist of ∼9 μm is used to transfer the Cr dots to an acceptor substrate. The threshold fluence is found to be ∼0.15 the threshold fluence of a similar continuous film, which is thought to be due to the fact that no force is needed to tear away Cr from the film itself, unlike in a continuous film experiment. Since the volume of the material limits the transfer feature sizes instead of the laser parameters, as in a continuous film system, minimum transferable feature diameters are significantly lower compared to the continuous film case. Also, the transferred feature diameters are not dependent on the laser parameters, so the diameters are consistent across a wide range of fluences. The force per unit area generated by the laser at threshold fluence is estimated to be ∼3 GPa, which is consistent with previous results in the literature. The simplified model that our pre-patterned Cr LIFT experiment represents would make it an ideal case for benchmarking molecular dynamics simulations of femtosecond laser ablation.

Pulsed laser deposition of uniform semiconductor nanodot arrays - Gupta, Manisha; Sauer, Vincent; Tsui, Ying Yin (Applied Physics A, 2012)
Uniform arrays of silicon (Si), gallium arsenide (GaAs) and zinc oxide (ZnO) nanodots have been deposited using Pulsed Laser Deposition (PLD) technique combined with a contact mask consisting of nano-holes fabricated by E-beam lithography (EBL). These nanocrystalline semiconductor nanodots have been deposited by PLD on Si and GaAs substrates at room temperature. Characterization of the nanodots has been carried out using different techniques including X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), Auger Electron Spectroscopy (AES), and Raman spectroscopy. This work demonstrates a novel technique for deposition of uniform array of semiconductor nanostructures using a contact mask at room temperature for photonic applications.

Direct observation of low-temperature catalytic decomposition of H3BO3 shell in core/shell Ni/H3BO3 nanoparticles - Zhang, X. F.; Guan, P. F.; Dong, X. L. (Applied Physics A, 2012)
Decomposition of H3BO3 to B2O3 in core/shell Ni/H3BO3 nanoparticles was in situ recorded by transmission electron microscope as the irradiation time. The direct observation provides compelling evidence of the synergetic effect of the Ni core and the H3BO3 shell, revealing the catalytic mechanisms of metal nanostructures that induce the decomposition at 124 °C, lower than the bulk counterpart at 300 °C. This phenomenon can be theoretically explained by considering the weakening of B–O bond at the Ni–H3BO3 interface, and has important implications in understanding the lubricant behavior of H3BO3 in frictional wear.

High-dielectric losses in stabilized γ-iron/graphite nanocomposites - Zhang, X. F.; Guan, P. F.; Medwig, J.; Dong, X. L. (Applied Physics A, 2012)
γ-iron and γ-iron/graphite nanoparticles were synthesized by a non-equilibrium cooling arc-discharge method. Experimental extinction spectra exhibit unexpected dielectric resonance of γ-iron nanoparticles at the microwave frequency, presenting the first metallic nanostructure of the high-dielectric loss. We further construct a multi-dielectric loss structure, with the enhanced dielectric loss factor of 0.7–0.9, by encapsulating the γ-iron into onion-like graphite nanoshells.

An evaluation of several in-lake restoration techniques to improve the water quality problem (eutrophication) of Saint-Augustin Lake, Quebec, Canada - Galvez-Cloutier, Rosa; Saminathan, Sumathi K. M.; Boillot, Clotilde; Triffaut-Bouchet, Gaëlle; Bourget, Alexandre; Soumis-Dugas, Gabriel (Environmental Management, 2012)
Increasing phosphorus (P) content and decreasing water quality of Saint-Augustin Lake, Quebec City, Canada, has led to implementation of an Integrated Watershed Management Plan to restore the lake. As a part of the plan, the effects of different restoration techniques on lake water quality and biological community (i.e., biological compatibility) were assessed during an isolated water enclosure study and laboratory microcosm assay, respectively. The restoration techniques include: (i) coagulation of P by alum only (20 mg L−1), (ii) active capping of sediments using a calcite layer of 10 cm, and (iii) a complete method involving both alum coagulation and calcite capping. The results showed that the total P (TP) was greatly decreased (76–95 %) by alum + calcite, followed by calcite only (59–84 %). Secchi depth was 106 % greater and chlorophyll a concentrations were declined by 19–78 % in the enclosure which received both alum and calcite. Results of the biological compatibility test showed that total phytoplankton biomass declined by 31 % in microcosms composed of alum + calcite. No significant (P > 0.05) toxic effect was found on the survival of Daphnia magna and Hyalella azteca in both alum only and alum + calcite microcosms. Although the alum + calcite technique impaired the survival of Chironomus riparius, the midge emergence was much higher compared to alum only and control. Overall, the alum + calcite application was effective in controlling P release from sediment and lowering water column P concentrations, and thus improving the water quality and aquatic life of Saint-Augustin Lake. However, the TP concentrations are still higher than the critical limit (20 μg L−1) for aquatic life and the water column remained in the eutrophic state even after treatment. Increased TP concentrations, to higher than ambient levels of the lake, in the water column of all four enclosures, due to bioturbation artefact triggered by the platform installation, likely cause insufficient dosages of alum and/or calcite applied and reduced their effectiveness.
Keywords: eutrophication; phosphorus; integrated watershed management plan; restoration technique; water quality; microcosm assay tests