bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Molecular Structure of POSS on Gas-Molecule Diffusion Coefficients Using Molecular Dynamic Simulation
Authors: Wang Di , Zhu Peng , Wei Shuang Ying , Hu Li Jiang
Published: June 2011

Polymorphic structure of polyhedral oligomeric silsesquioxanes (POSS) derived from hydrolytic condensation of vinyltrimethoxysilane was validated by the spectral characterization, such as FTIR, UV-MALDI-TOF MS,etc. Discover module of Materials Stutio (MS) software which is a molecular dynamic simulations (MDS) program has been used to estimate the self-diffusion coefficients of small gas molecules in models of hybrid materials that validates the corresponding anticorrosion-experiment results. The models of 3D-amorphous cubic unit cells of different numbers of Si atom and hydroxyls generated during the hydrolytic condensation (T6, T7, T8, T9, T10,T8(OH)2and T8(OH)4cells), were employed to investigate self-diffusion coefficients by MDS for the N2, O2, Cl2, CO2, NO2, SO2and H2O molecules. The simulations results showed that all seven self-diffusion coefficients of N2, O2, Cl2, CO2, NO2, SO2and H2O in cells increased with the numbers of Si atoms and the generated hydroxyls. This increasing was discussed by the calculation, compared to the vinyltrimethoxysilane hybrid systems.
Interface Movement and Microstructure Evolution of Interdiffusion in the Binary Alloy Diffusion Couples
Authors: Li Yong Sheng , Yu Yan Zhou , Cheng Xiao Lin , Chen Guang
Published: June 2011

The phase field simulation of interface movement and interdiffusion microstructure in a binary diffusion couples was developed. The diffusion couples with nonequilibrium concentration for single phase or single phase and two-phase including the temperature and mobility effects were studied. It’s shown that the interface movement and the atoms diffusion direction were determined by the magnitude of relative concentration difference between the initial concentration and the equilibrium concentration, the distance of interface movement and interdiffusion flux increases as the temperature or the mobility increasing, and the large mobility makes the particles coarsening faster.
Microscopic Phase Field Study on the Site Preference of Al in Ni3V: Coordination Geometry Effect
Authors: Zhang Ming Yi , Chen Zheng , Fan Xiao Li , Wang Yong Xin , Lu Yan Li
Published: June 2011

The site occupation behavior of Al in Ni3V phase with a DO22structure in Ni75AlxV25-xalloy was studied using the microscopic phase-field model which is based on the microscopic diffusion equations. Attribute to the coordination geometry effects, the concentration of Al are non-equal on the two non-equivalent Ni sites, and Al prefers to occupy the NiⅠsites. However, the Al does not prefer to occupy both of the two Ni sites, because the Al concentration on V site is intermediately between that on NiⅠand NiⅡsite. The calculated ordering energies suggest that the site preference of alloying elements are all energetic favorable.
3D Numerical Simulation of Flow and Temperature Field in Semi-Solid Slurry Preparation by A-EMS
Authors: Tang Meng Ou , Xu Jun , Zhang Zhi Feng , Bai Yue Long
Published: June 2011

Annular electromagnetic stirring (A-EMS) process is an advanced semi-solid metal processing technology. It could avoid the effect of skin effect, increase the shear rate, reduce the temperature gradient and refine microstructures. A three-dimensional computational model sequentially coupling electromagnetic stirring with a macroscopic heat and fluid flow in A357 alloy semisolid slurry preparation by A-EMS has been developed. Comparison between microstructures of A357 alloy produced by EMS and A-EMS has been made. The results show that the annulus gap avoids the part of low magnetic induction intensity and A-EMS avoids the effect of skin effect. The annulus gap prohibits the circular flow and increases the shear flow. The circular flow is more effective than the shear flow on heat dissipation. A lower temperature difference in the stirred melt and subsequent uniformly fine microstructures were obtained as compared with the normal electromagnetic stirring.
Moleculer Dynamics Study of the Thermodynamic Shear Deformation in TiAl/Ti3Al System
Authors: Liu Yong Li , Bao Jian Zhi , Zhang Lin , Wang Shao Qing , Ye Heng Qiang
Published: June 2011

TiAl alloys have great potential because of its low density and the outstanding performance at high temperature. However, the brittleness influences its industrialization process. It is known that the macroscopic nature is greatly influenced by its microscopic structure, and the fault development plays a vital role during the material working process. The paper performed the molecular dynamics (MD) study of the thermodynamic shear deformation in TiAl/Ti3Al system to promote the understanding in this aspect. Above all, we adopt a special shear deformation model based on the experimental consideration, and conduct the optimal calculation of the related parameters. Then, a series of thermodynamic deformation simulation were carried out using the previous optimized model. The analysis of the potential variation and the structural snapshots showed that the shear deformation is related with the “stick-slip” behavior. The Ti3Al (TiAl) shows obvious (little) covariant deformation stage before the initiation of the fault transition. For Ti3Al region near the interface, the final structure is the continued FCC stacking. For TiAl, twin and SISF are observed and the block of twin is the main remnant. The atomic diffusion is locally observed in Ti3Al phase. The interface transits the energy and counterpoises the deformation between the hetero-phases.
Numerical Simulation of 300mm CZ Silicon Crystal Growth with Axial Magnetic Fields
Authors: Xu Wen Ting , Tu Hai Ling , Chang Qing , Xiao Qing Hua , Dai Xiao Lin , Liu Yun Xia , Li Zong Feng , Chang Lin , Liu Wei Da
Published: June 2011

We studied the optimization of 300mm CZ silicon crystal growth in 28 inch hot zone with axial magnetic field. The convex of melt-crystal interfaces toward to the crystal are observed in our simulations under different growth velocities (0.3mm/min, 0.5mm/min and 0.65mm/min). The convections in melt were illustrated under different growth rates and intensities of magnetic field. The growth rate of 0.5mm/min and axial magnetic fields intensity of 0.3T were recommended as an appropriate control condition.
Study on the Process Optimization of Synthesizing Co3O4 Nanoparticles by Homogeneous Precipitation Based on Support Vector Regression
Authors: Cai C.Z. , Zhu X.J. , Pei J.F. , Wang G.L.
Published: June 2011

The Co3O4 is the major raw material for fabricating lithium cobalt oxide electrode of lithium ion battery. According to the experimental dataset on grain diameter of Co3O4 nanoparticles synthesized by homogeneous precipitation under four main process parameters including the concentration of Co(NO3)2•6H2O solution, mole ratio of reactants, reaction temperature and reaction time, support vector regression (SVR) combined with particle swarm optimization (PSO) for its parameter optimization, is introduced to establish a model for estimating grain diameter of Co3O4 nanoparticles. The comparison of prediction results strongly support the prediction and generalization abilities of SVR are superior to those of multivariable gradual regression (MGR). Meanwhile, the index of grain diameter of Co3O4 nanoparticles under an independent combination of process parameters predicted by SVR model is more accurate than that by MGR model. The multi-factors analysis results based on SVR model are consistent with that of the literatures. This study suggests that SVR is a theoretical significance and potential practical value in development of smaller grain diameter of Co3O4 nanoparticles via guiding experiment.
The Simulation of Stress-Induced Phase Transition of L10 Re-Precipitation Based on Microscopic Phase-Field Model
Authors: Wang Yong Xin , Wang Yong Biao , Chen Zheng , Lu Yan Li
Published: June 2011

It is common that the pre-precipitation phase with kinetics advantage is found during non-equilibrium transformation. The continuously changed stress in the transformation increases the complication of precipitation process. The stress induces Ll0pre-precipitation phase in Ni75-Al12.5-V12.5alloy is studied by microscope phase-field model in this paper. It is particularly show that Ll2phase precipitates directly without stress. There is no Ll0phase to be found in the disordered matrix. Oppositely, Ll0phase precipitates firstly with stress, and then it turns into Ll2phase. When stress is less, either or both above situations are observed. While stress is stronger, a large range of Ll0phase precipitates firstly. Then a part of it dissolves. The rest turns into Ll2phase. The precipitation of pre-precipitation phase accelerates the precipitation process. The larger the stress and the more Ll0phase precipitation, the longer it exists and the shorter the induction period is.
Occupation and Magnetic Property of Cr Additive in L10 FePt: First-Principle Study
Authors: Shu Da Song , Shu Xiao Lin , Chen Zi Yu
Published: June 2011

The preference site and magnetic property of doped Cr atom in L10 FePt alloy are investigated by the first-principles calculations. Due to the energy of Cr located in Fe and Pt sublattice are -0.15 and 0.48 eV, respectively, the Cr atom occupying Fe site is more energetic favorable than in Pt site in L10 FePt alloy. The calculated saturation magnetizations for Cr additive replacing Fe or Pt atom in L10 FePt are 959 or 989 emu/cm3, respectively. The results are lower than that of L10 FePt (1085emu/cm3). The additive of Cr in L10 FePt will reduce the saturation magnetization.
The Relationship between Grain Boundary Character Distribution and Intergranular Corrosion Resistance of 304 Austenitic Stainless Steel
Authors: Fang Xiao Ying , Cui Xiao , Qin Cong Xiang , Wang Wei Guo
Published: June 2011

A wedge-shaped 304 austenitic stainless steel with varied thickness longitudinally was cold rolled into a flat one and then annealed at 1323K for 10 min. The grain boundary character distributions (GBCDs) in the specimen as processed were examined by the means of Electron backscatter diffraction (EBSD). The results showed that, at the regions with low pre-strains ranged from 4% to 6%, quite high fractions of S3n (n=0,1,2,3) grain boundaries and large-sized S3n (n=0,1,2,3) grain clusters are introduced compared with the regions of quite low ( less than 2.5%) or relatively high pre-strain. The surface appearance of after corrosion test reveals that grain dropping due to intergranular corrosion (IGC) is depressed and the penetration of IGC from the surface into the interior in the cross-section is arrested significantly as well in the regions with high fractions of S3n boundaries and large-sized S3n grain clusters.
Characterization of Intergranular Corrosion in Heat-Affected Zone of Low Carbon 12Cr-Ni Ferritic Stainless Steel
Authors: Zheng Huai Bei , Ye Xiao Ning , Cai Zheng , Jiang Lai Zhu , Liu Zhen Yu , Wang Guo Dong , Wang Bao Sen
Published: June 2011

Intergranular corrosion in heat-affected zone of low carbon 12Cr-Ni ferritic stainless steel was investigated by the method of practice Z in ASTM A 763-93. The microstructure of welded joint was characterized using an optical microscope and a scanning electronic microscope. Severe intergranular corrosion (IGC) was only observed in low temperature heat-affected zone (LTHAZ) adjacent to base metals at the back of the welded joints in unstabilized steel. On the other hand, IGC was not observed in the welded joints of stabilized steels. According to the analysis of microstructure, the severe IGC is attributed to both the precipitated phase along the grain boundaries inducing the presence of chromium-depleted zone and the welding residual tensile stress promoting the corrosion. Therefore, stabilized elements addition such as Ti and Nb is required in order to avoid the IGC in welded joint of these steels. Relief residual tensile stress by post weld heat treatment would also be an effective method to avoid the IGC in the welded joints of these steels.
Effect of Plate Thickness and Weld Position on Distortion and Residual Stress of Welded Structural Steel
Authors: Anis Muhammad , Winarto
Published: June 2011

Residual stresses are generated as a result of non-uniform temperature distribution during welding and particularly cooling process during fabrication of the welded parts. Residual stresses have a major effect on the overall performance of a component in service. In this instant, the residual stress in the form of angular distortion is primarily caused by shrinkage on longitudinal and transversal direction. Several single v-butt joints on structural steel plates of SS400 are investigated by using different plate thickness and welding positions (1G and 3G). GMAW method was used in the welding process. Measurement of residual stress was carried out on a plate with the thickness of 16 mm on longitudinal, transversal and normal direction by using neutron diffraction method. Results showed that the angular distortion of the welded plates increase with the increase of plate thickness. Welding by vertical position (3G position) resulted in a bigger angular distortion compared to flat position (1G position). The distribution of residual stress varied between tension and compression residual stress along welded area with the range of -10 mm to 10 mm. Measurement of residual stress on the longitudinal direction has the greatest value among two other directions.
Effect of Environmental Factors of Mannanase on Konjac Glucomannan Molecular Dimension
Authors: Long Xiao Yan , Luo Xue Gang , Bai Ju , Zhu Jia Feng
Published: June 2011

The environmental factors of mannanase konjac glucomannan (KGM) have been investigated in aqueous solution. Molecular weight (Mw) and molecular weight distribution (WMD) of the degraded KGM were measured by GPC. During the degradation process, the molecular weight of the enzymatic products decreases with reaction time, degradation reaction combining two reactions processed with different orders, while WMD broadens at first and then becomes narrow. The reduction of molecular dimension of KGM was lowered with temperature increase, but WMD increases. WMD was reduced with concentration of enzyme increase, but the reduction of molecular dimension of KGM was insignificant in the range of 2.0~6.5 u.mL-1of mannanase concentration. The results show that molecular dimension of KGM could be controlled by soft changes of reaction environment, dimension of KGM molecule could be decreased more than 100 times so as to obtain oligosaccharides, which offers the reference to reliable theoretical foundations and practical ground in exploiting KGM potential function and activity.
LDPE/EVA Modified Film Prepared by Melt Blend Method and Study of its Mechanical Performances and Barrier Property
Authors: Shi Qing Ping , Li Dong Li , Xu Wen Cai
Published: June 2011

In this study, six kinds of different films from LDPE (Low-density polyethylene) modified by EVA (Ethylene - vinyl acetate copolymer) were made, and EVA / LDPE mass ratio was 0/50, 1/49, 1/ 19 4/21, and 1/3. Influence of EVA amount on the properties of LDPE film was investigated using the Instron universal testing machine, DSC, oxygen permeability tester and breathable apparatus. The mechanical properties of the blended films showed that when the EVA content was 5%, LDPE / EVA film transverse Young's modulus increased by about 50%, and the vertical Young's modulus increased by about 56%, which is good for improving the overprint accuracy of the LDPE / EVA film. DSC analysis showed that the melt blending has no effect on the thin-film processing temperature and thermal stability, but the result indicated that the crystallinity of the blended films was lowered with the increase of EVA amount. Barrier tests showed that with the increase of EVA content, the barrier of the modified films was decreased. The polarity of the film increased with more EVA component, which would augment the surface tension of LDPE and its ink adhesion.
Mechanism of Large Elastic Modulus of Bone
Authors: Chen Bin , Yin Da Gang , Luo Ji , Yuan Quan , Fan Jing Hong
Published: June 2011

Scanning electron microscope (SEM) observation shows that fibula bone is a kind of bioceramic composite consisting of hydroxyapatite layers and protein matters. The hydroxyapatite layers are further composed of hydroxyapatite sheets. The observation also shows that the hydroxyapatite sheets possess quite large volume fraction and also have very long and thin fiber shape. The mechanism of the large volume fraction of the hydroxyapatite sheets to ensure the larger elastic modulus of the bone was investigated based on the model of the bone composite and the theory of the composite mechanics. The investigated result reveals that the large volume fraction of the hydroxyapatite sheets endows the bone with large elastic modulus.
Correlation between Microstructure and Toughness of Crab Carapace
Authors: Chen Bin , Yin Da Gang , Yuan Quan , Fan Jing Hong
Published: June 2011

Crab carapace is a kind of biomaterial in nature. It behaves favorable strength, stiffness and fracture toughness, which are closely related to its fine microstructure. The observation of scanning electron microscope (SEM) on the carapace of a Cyclodorippoidea crab shows that the carapace is a kind of natural bioceramic composite consisting of calcite crystal layers and collagen protein matrix. The observation also shows that the calcite crystal layers consist further of long and thin calcite crystal sheets and that all the calcite crystal sheets are arranged in a kind of parallel distribution. The maximum pullout energy of the calcite crystal sheets, which is closely related to the fracture toughness of the carapace, is investigated based on the representative model of the parallel distribution. It shows that the long and thin shape as well as the parallel distribution of the calcite crystal sheets enhance the maximum pullout energy and ensure the high fracture toughness of the carapace.
SEM and AFM Studies on the Surface and Cross Section Morphology of Rayon-Based Activated Carbon Fibers
Authors: Wang Guang Xue , Han Hao , Li Li Wei , Quan Hai Yu , Shi Yan Ping , Qin Wen Zhen , Lu Ping , Wu Qi Lin
Published: June 2011

The surface and cross section morphology of rayon-based carbon fibers (RCF) and the resulting rayon-based activated carbon fibers (RACF) were investigated through scanning electron microscopy and atomic force microscopy. It was found that the surface of RCF exhibited grooves and striations with the width ranging from 30 to 90 nm, and the striation distribution was about 25 bars per µm around the circumference. While on the RACF, lots of pores emerged on the surface and superficial cross section (about 1 ~ 2 µm to the surface), namely, the external section was porosity but the interior section was close-grained. It was detected that the pore sizes ranged from 50 to 550 nm and the approximate pore distribution was 10 pores in 1×1 µm2. Furthermore, the walls of pores were not smooth but consisted of continuous grains with the diameters about 30 nm.
Atomic Anti-Site Evolution during L12 Precipitation Using Microscopic Phase-Field Simulation
Authors: Liang Min Jie , Liao Hai Hong , Ding Wen Jiang , Chen Zheng
Published: June 2011

The influence of temperature on atomic site occupation probability (SOP) in L12--Ni3(Al1-xFex) has been studied using microscopic phase-field simulation for Ni3Al-Fe alloy with the lower Fe content. Microscopic phase-field kinetics model was further extended to study the temporal evolution of atomic site occupation and atomic anti-sites behavior, which was revealed in detail at the different temperatures. The results show that the size, number and the precipitation mechanism of L12phases also present obvious changes with the increase of temperature. The SOP of each atom on its right-sites decreases slowly; while the SOP of Fe atoms are far lower than those of Al atoms. On the other hand, the SOP of each atom on its anti-sites increases gradually. The formation of NiAl(Ni atoms form anti-sites on Al sites) is more easily and the formation of NiAlis more sensitive to temperature than that of FeNi(Fe atoms form anti-sites on Ni sites). Atomic site occupation will not evolve during the early stage of precipitation, which becomes more and more obvious.
Studies on the Thermodynamic and the Miscibility Gap of the Cu2O-Al2O3-SiO2 Pseudo-Ternary System
Authors: Xiao Qiu Guo , Ding Gang Cheng , Long Tang Zhong , Zhang Ming Min , Shen Shao Hua
Published: June 2011

Cu2O-Al2O3-SiO2 ternary system of given compositions can be used as a kind of thermal shock resistance sealing materials for electronic devices. So far, little systematic work was reported on the phase behavior and phase equilibrium at a high temperature, except the isothermal section of a CuO-Al2O3–SiO2 ternary system at 950 and 1150°C. We have investigated the thermodynamic behavior and the microstructure of the compositions in the miscibility gap of the Cu2O-Al2O3-SiO2 pseudo-ternary system on the basis of the reported isothermal section of this system at 1150°C based on the analyzing of the differential scanning calorimeter and the observing of the scanning electronic microscope. The eutectic point of the Cu2O-Al2O3-SiO2 pseudo-ternary system was determined by the thermal analysis. Then, the changing rule of the microstructures with different compositions was investigated. The results indicated that large differences existed among the different compositions in the miscibility gap of Cu2O-Al2O3-SiO2 ternary system.
Tensile Fracture Characteristics of Polysulfide Sealants Immersed in Oil
Authors: Ding Mei Li , Zhang Wei Fang , Hou Wei Guo , Liu Xiao
Published: June 2011

In this paper, the morphology characteristic of tensile test fracture of polysulfide sealants immersed in oil for different time was observed through scanning electron microscopy. Combined with the performance data of tensile test, the effect of oil immersion time on the properties and fracture behavior of sealant was studied. The results show that the fracture of polysulfide sealants includes rough region and flat region. After being immersed in oil, the area of rough region diminishes and the roughness of fracture decreases. Within 168h, oil immersion time has little effect on the tensile strength and elongation of sealants.
Time-Dependant Effect Evaluation of Surface Characters in Seawater of Fouling-Release Antifouling Coatings Based on Fluoro-Copolymer
Authors: Zhang Zhan Ping , Qi Yu Hong , Luo Xiao Liang
Published: June 2011

To develop new non-toxic antifouling coating, some fouling-release(FR) coatings based on fluoro-copolymer and silicone polymer were formulated. Coatings specimens were rotated in a laboratory device at different simulating speeds of a ship for some periods. The film thickness, surface roughness, water contact angle of all coatings were measured and investigated. The relationship between the performance and testing time, and the effect of simulating speed on the performance were studied and discussed. The research results show that the time spent on evaluating the performance of ship antifouling coatings was shortened. The film thickness of all coatings decreases with test time. FR antifouling coatings surface roughness increase slowly, and their surface contact angle decrease gradually with time. Increasing of the simulating speed will accelerate the surface of all the coatings trend to rougher, increase the ablation rate of the coatings and the change of water contact angle of FR coatings.
Influence of Molecular Structure on the Optical Property of POSS: a DFT Calculation Based Quantum Chemistry Calculation
Authors: Wang Di , Zhu Peng , Wei Shuang Ying , Hu Li Jiang
Published: June 2011

Polymorphic structure of polyhedral oligomeric silsesquioxanes (POSS) derived from hydrolytic condensation of vinyltrimethoxysilane was validated by the spectral characterization, such as FTIR, UV-MALDI-TOF MS, etc. The models of 3D-amorphous cubic unit cells of different numbers of Si atom and hydroxyls generated during the hydrolytic condensation and the length of the organic side chain (T6, T7, T8, T9, T10, T8(OH)2and T8(OH)4cells), as models were established with a materials visualizer module of Material Studio(MS) software. The cells were optimized the configuration and calculated energy band structure and absorption coefficient (a) with Castep module of MS which is the quantum chemistry program based on density functional theory (DFT). The calculation results showed that the band gap was reduced with the number of Si atoms in POSS increased, but the presence of hydroxyl could make a significant reduction of them. The reduction of band gap would lower the frequency of the incident light that was absorbed by the POSS and heighten the wavelength of the absorbed incident light, which was proved by the calculation results of absorption coefficient. Such reduction was discussed in comparison with the vinyltri- methoxysilane hybrid systems.
Density-Functional Investigation of Lun (n=2-14) Clusters
Authors: Zhang Chuan Hui , Pen Qi , Shen Jiang
Published: June 2011

The binding energies, ground state geometries, and electronic properties of the rare earths metal neutral Lun(n=2–14) clusters, cations, and anions have been systematically investigated by using DFT. The ground state structures of the clusters with 4 and 11 atoms are found to be magic. We get some different property comparing with Lancluster [J. Chem. Phys. 120, 5104 (2004)], which belongs to lanthanide. Lu13cluster is an icosahedral structure with magnetic moment of 1μB, the occupied states of Lu13are highly degenerated. It has largep-dhybridization, which makesPDOSpeaks value below Fermi level moving to the Fermi level.
Update on the Serum Biomarkers and Genetic Factors Associated with Safety and Efficacy of rt-PA Treatment in Acute Stroke Patients
Authors: Nafría C. , Fernández-Cadenas I. , Mendioroz M. , Domingues-Montanari S. , Hernández-Guillamón M. , Fernández-Morales J. , del Río-Espínola A. , Giralt D. , Deu L. , Delgado P. , Rosell A. , Montaner J.
Published: June 2011

An accurate understanding of the mechanisms underlying an individual's response to rt-PA treatment is critical to improve stroke patients' management. We thus reviewed the literature in order to identify biochemical and genetic factors that have been associated with safety and efficacy of rt-PA administration after stroke.
Lentiviral-Mediated shRNA Silencing of PDE4D Gene Inhibits Platelet-Derived Growth Factor-Induced Proliferation and Migration of Rat Aortic Smooth Muscle Cells
Authors: Liu Lin , Xu Xiaowei , Li Jiejie , Li Xia , Sheng Wenli
Published: June 2011

Phosphodiesterase 4D (PDE4D) is a member of the large superfamily of phosphodiesterases. PDE4D polymorphisms have been found to associate with ischemic stroke. Proliferation and migration of vascular smooth muscle cells (VSMCs) play a critical role in the pathogenesis of atherosclerosis. In this study, infection of VSMCs with lentivrius particles carrying shRNA direct against PDE4D significantly inhibited platelet-derived growth factor-induced VSMC proliferation and migration, and the inhibitory effects were not associated with global intracellular cAMP level. Our results implicate that PDE4D has an important role in VSMC proliferation and migration which may explain its genetic susceptibility to ischemic stroke.
Dicer Functions in Aquatic Species
Authors: Kitagishi Yasuko , Okumura Naoko , Yoshida Hitomi , Tateishi Chika , Nishimura Yuri , Matsuda Satoru
Published: June 2011

Dicer is an RNase III enzyme with two catalytic subunits, which catalyzes the cleavage of double-stranded RNA to small interfering RNAs and micro-RNAs, which are mainly involved in invasive nucleic acid defense and endogenous genes regulation. Dicer is abundantly expressed in embryos, indicating the importance of the protein in early embryonic development. In addition, Dicer is thought to be involved in defense mechanism against foreign nucleic acids such as viruses. This paper will mainly focus on the recent progress of Dicer-related research and discuss potential RNA interference pathways in aquatic species.
Determinants of young people’s sexual behaviour concerning HIV and AIDS in the practice population of a university health centre in Lagos, Nigeria
Authors: Ayankogbe Olayinka O. , Odusote Kofo , Omoegun Mopelola O. , Ofoha Victoria , Adedokun Ayoade , Abiola Kehinde O.
Published: June 2011

Background: AIDS has been a scourge of universities in Africa for a long time. This study was launched at ground-level to fight the dreaded disease by concentrating on young people and to counter the ignorance that surrounds the disease even in numerous African universities. This study of the student community was carried out by family doctors at the University Health Department to determine the prevalence of the determinants of young people’s reproductive health behaviour. Objectives: This study is aimed at determining young people’s sexual behaviour concerning HIV and AIDS in the practice population of a university in Lagos, Nigeria.Method: Self-administered 63-item questionnaires were distributed amongst 2000 randomly selected students of the University of Lagos, Lagos, Nigeria in September 2005, using a semistructured form of the Comprehensive Youth Survey questionnaire, developed by FOCUS (led by Pathfinder International, Futures Group International and Tulane University School of Public Health).Results: The age distribution of the respondents was designated in the age groups of 15–19 years (15.8%), 20–24 years (60.1%), 25–29 years (19.6%), 30–34 years (2.8%).Demographics of note were that 88.3% of the fathers of the respondents were literate and that 94.5% of the fathers earned more than one US $ per day. The majority of the respondents (99.1%) indicated adherence to one religious faith or the other and 58.8% believed definitely that religion shaped their attitudes about sexual intercourse and sexuality. More than half (64.0%) denied having had sex at all in the three months preceding the study. Furthermore, 68.8% affirmed that it was common amongst friends of their age to use condoms. A significant number of respondents (65.5%) thought that their friends have drunken alcohol. Almost all of the respondents (94.3%) had a positive perception of their family.Conclusion: The Programming for HIV and AIDS Reduction on university campuses in Africa should be conducted comprehensively rather than monothematically and should, take into consideration the five thematic areas of behaviour change communication amongst young people concerning their reproductive health.
Anidulafungin: Review of its Role in the Treatment of Invasive Candidiasis
Authors: de la Torre Pola , Reboli Annette C.
Published: June 2011

In 2006 a third echinocandin, anidulafungin, was approved in the USA for the treatment of candida esophagitis, candidemia, and invasive candida infections such as intra-abdominal abscesses and peritonitis in the non-neutropenic patient. Two years later it was approved in the EU for invasive candidiasis in non-neutropenic patients. Like other echinocandins, it is fungicidal against Candida species and fungistatic against Aspergillus species. It does not need adjustment for renal or hepatic insufficiency, and has no known drug interactions. Its administration is by the intravenous route only, and it is well tolerated. A steady state concentration can be achieved on day two by giving twice the maintenance dose on day one.
The use of silver nitrate for the identification of spermatozoon structure in selected mammals
Authors: Andraszek Katarzyna , Smalec Elżbieta
Published: June 2011

Andraszek, K. and Smalec, E. 2011. The use of silver nitrate for the identification of spermatozoon structure in selected mammals. Can. J. Anim. Sci. 91: 239–246. The spermatozoon is one of the most diversified cell types, and the chromatin of the haploid spermatozoon genome is essentially different from that of the somatic cell as regards its chemical composition, structure and function. Although the structure of spermatozoon chromatin has crucial importance for fertilization and embryo development, standard staining techniques are still predominantly used for identifying semen quality and the assessment of spermatozoa is most often limited to detecting irregularities in their morphological structure. The aim of the present research was to evaluate the usefulness of silver nitrate staining for assessing spermatozoon morphology and identifying spermatozoon structure. Spermatozoa isolated from testes and semen were examined. Silver nitrate staining made it possible to identify many significant details of the morphological structure of the spermatozoon and could be successfully employed in sperm morphology assessments.
Effects of short-term oilseed supplementation on reproductive performance in beef heifers
Authors: Scholljegerdes E. J. , Lekatz L. A. , Vonnahme K. A.
Published: June 2011

Scholljegerdes, E. J., Lekatz, L. A. and Vonnahme, K. A. 2011. Effects of short-term oilseed supplementation on reproductive performance in beef heifers. Can. J. Anim. Sci. 91: 221–229. The objective of this experiment was to evaluate the role of a short-term increase in linolenic acid around the timed artificial insemination (TAI) on plasma fatty acid concentrations, estrous behavior, and pregnancy. Therefore, 96 cross-bred heifers (Initial BW=394±18.1 kg) fed chopped grass hay were allotted to one of three dietary treatments: no supplement (CON); 1.8 kg head−1d−1(DM basis) of a soybean-based pellet (SOY) high in linoleic acid (C18:2n-6); or 1.5 kg head−1d−1(DM basis) of a flaxseed-based pellet (FLX) high in linolenic acid (C18:3n-3). On day −9, relative to TAI, supplementation began, and heifers received a controlled internal drug-releasing (CIDR) device and gonadotropin releasing hormone (GnRH; 100 µg). On day −2, CIDRs were removed and heifers received 25 mg prostaglandin F2α (PGF2α). Heifers were bred by TAI (day 0) 54 h after CIDR removal and received GnRH. Estrous behavior was monitored throughout the feeding period by radiotelemetry. Supplementation ended on day 18 relative to TAI. Plasma concentrations of C18:2n-6 were greater by day 0 and day 18 (P<0.001) above that of CON for both SOY and FLX with SOY being greater than (P<0.001) FLX. Likewise, C18:3n-3 was also greater for supplemented heifers by day 0 and day 18 (P<0.001). The number of heifers that did not respond to estrous synchronization was not affected by dietary treatment (P=0.61). Conception to AI was not affected by treatment (P=0.24). Overall pregnancy rates tended to be lower for FLX (P=0.08) than SOY. Conception to a TAI program was not enhanced when oilseeds were fed to beef heifers during estrous synchronization and continuing past day 18 relative to artificial insemination.
Organic Hummus in Israel: Global and Local Ingredients and Images
Authors: Grosglik Rafi
Published: June 2011

Hummus is an ancient traditional dish in Middle Eastern Cultures. In Israel it is one of the most common foods, appropriated as an icon of Israeli culture and nationality. Today, hummus is served in Israel in many restaurants, and is even distributed as a commercially packaged spread sold in supermarkets. Organic hummus – a recent version of the dish – is influenced by global trends of ethical and reflexive food consumption. Organic food is conceived as the spearhead opposing the consequences of globalization. It is customary to view it as representing locality, health, ecology and social justice. But it also embodies representations of globalism and westernism, mainly because of its integration in the global industrial system and its origin among the post-materialistic-social elite in western countries. This article deals with the encounter of the global and the local as embodied in organic hummus in Israel. Looking at the production, distribution, and consumption of this dish uncovers social and political layers embedded in it. I will argue that the global socio-economic conditions and ideas embedded in the concept of organic attached to hummus are the ones which allow – paradoxically – the imagined re-localization of the dish. Organic hummus in Israel is a dish steeped in paradoxical aspects, and therefore characterized by culinary-ideological-dissonance. Hummus is a dish that was perceived as representing rootedness, earthiness, and local simplicity, but nowadays, in its organic version, it wears an economic and symbolic framework of global values used by the Israeli westernizing elite to demonstrate a widespread-environmental cosmopolitan identity.
The Subject of Functional Foods: Accounts of Using Foods Containing Phytosterols
Authors: Weiner Kate
Published: June 2011

This paper explores the notion of the late modern or reflexive subject, for whom consumption, rationality, autonomy and a reflexive attitude to risk are said to be constitutive. Drawing on an example of ‘ordinary’ health consumption ( GRONOW and WARDE, 2001 ), the paper addresses what kinds of consumer identities emerge in people's talk about buying or eating foods containing phytosterols. These are ‘functional foods’ which are marketed on the basis that they actively lower cholesterol. Based on interviews with people who say that they buy or eat these foods, the analysis focuses on participants’ reported trajectories relating to how this came about. Participants’ accounts contain a number of explicit and implicit reasons for buying or eating the foods, which I characterise as agential, contextual, or non-agential, depending on the degree to which they draw on the agency of the actual purchaser or eater. These different types of explanations can be ordered in terms of their appeals to rationality, risk consciousness and autonomy. In agential explanations, people talk, for example, of doing something good for themselves, or experimenting with the foods. These explanations explicitly position consumers as health conscious, autonomous and rational to varying degrees. Contextual explanations drew on, for example, the role of doctors or family history in alerting people to a potential problem. These suggest both a different sense of risk consciousness, which may be prompted or contextual, and a less autonomous kind of consumer who is connected to others through a set of family and other relationships. Non-agential explanations, for example, where people attributed their consumption to others or to habit, appeal neither to the rationality, the health consciousness nor the autonomy of the actual consumer. The analysis helps to reinforce the potentially contextual or fluctuating nature of risk consciousness, and the relational and non-instrumental aspects of daily practices.
Regulating Social Research: Exploring the Implications of Extending Ethical Review Procedures in Social Research
Authors: Melrose Margaret
Published: June 2011

Reflecting on my experience of leading several qualitative research projects to investigate ‘sensitive’ topics with potentially ‘vulnerable’ participants, this paper considers the impact and consequences of increased ethical regulation in relation to my own research field and social research more generally. It argues that extending ethical regulation threatens social research in general, and specifically, threatens the study of ‘sensitive’ topics with ‘vulnerable’ populations. The consequences of increased ethical regulation may contradict its intention and place ‘vulnerable’ participants at greater risk than ‘sensitive’ research undertaken with such groups in earlier historical periods. The paper urges social researchers to act collectively, to engage with ethical regulatory regimes in order to challenge the threats they pose to scholarship, and by doing so, defend the value of social research for advancing knowledge so that our scholarship might better serve the populations we study.
Volatilizable biogenic organic compounds (VBOCs) with two dimensional gas chromatography-time of flight mass spectrometry (GC × GC-TOFMS): sampling methods, VBOC complexity, and chromatographic retention data
Authors: Pankow J. F. , Luo W. , Melnychenko A. N. , Barsanti K. C. , Isabelle L. M. , Chen C. , Guenther A. B. , Rosenstiel T. N.
Published: June 2011

Abstract. Two dimensional gas chromatography (GC × GC) with detection by time-of-flight mass spectrometry (TOFMS) was applied in the rapid analysis of air samples containing highly complex mixtures of volatilizable biogenic organic compounds (VBOCs). VBOC analytical methodologies are briefly reviewed, and optimal conditions are discussed for sampling with both adsorption/thermal desorption (ATD) cartridges and solid-phase microextraction (SPME) fibers. Air samples containing VBOC emissions from leaves of two tree species (Cedrus atlantica and Calycolpus moritzianus) were obtained by both ATD and SPME. The optimized gas chromatographic conditions utilized a 45 m, 0.25 mm I.D. low-polarity primary column (DB-VRX, 1.4 μm film) and a 1.5 m, 0.25 mm I.D. polar secondary column (Stabilwax® 0.25 μm film). Excellent separation was achieved in a 36 min temperature programmed GC × GC chromatogram. Thousands of VBOC peaks were present in the sample chromatograms; hundreds of tentative identifications by NIST mass spectral matching are provided. Very few of the tentatively identified compounds are currently available as authentic standards. Method detection limit values for a 5 l ATD sample were 3.5 pptv (10 ng m−3) for isoprene, methyl vinyl ketone, and methacrolein, and ~1.5 pptv (~10 ng m−3) for monoterpenes and sesquiterpenes. Kovats-type chromatographic retention index values on the primary column and relative retention time values on the secondary column are provided for 21 standard compounds and for 417 tentatively identified VBOCs. 19 of the 21 authentic standard compounds were found in one of the Cedrus atlantica SPME samples. In addition, easily quantifiable levels of at least 13 sesquiterpenes were found in an ATD sample obtained from a branch enclosure of Calycolpus moritzianus. Overall, the results obtained via GC × GC-TOFMS highlight an extreme, and largely uncharacterized diversity of VBOCs, consistent with the hypothesis that sesquiterpenes and other compounds beyond the current list of typically determined VBOC analytes may well be important contributors to global atmospheric levels of organic particulate matter.
Deglaciation records of 17O-excess in East Antarctica: reliable reconstruction of oceanic relative humidity from coastal sites
Authors: Winkler R. , Landais A. , Sodemann H. , Dümbgen L. , Prié F. , Masson-Delmotte V. , Stenni B. , Jouzel J.
Published: June 2011

Abstract. We measured δ17O and δ18O in two Antarctic ice cores at EPICA Dome C (EDC) and TALDICE (TD), respectively and computed 17O-excess with respect to VSMOW. The comparison of our 17O-excess data with the previous record obtained at Vostok (Landais et al., 2008) revealed differences up to 35 ppm in 17O-excess mean level and evolution for the three sites. Our data showed that the large increase depicted at Vostok (20 ppm) during the last deglaciation, is a regional and not a general pattern in the temporal distribution of 17O-excess in East Antarctica. The EDC data display an increase of 13 ppm, whereas the TD data show no significant variation from the Last Glacial Maximum (LGM) to the Early Holocene (EH). Lagrangian moisture source diagnostic revealed very different source regions for Vostok and EDC compared to TD. These findings combined with the results of a sensitivity analysis, using a Rayleigh-type isotopic model, suggest that relative humidity (RH) at the oceanic source region (OSR) are a determining factor for the spatial differences of 17O-excess in East Antarctica. However, 17O-excess in remote sites of continental Antarctica (e.g. Vostok) may be highly sensitive to local effects. Hence, we consider 17O-excess in coastal East Antarctic ice cores (TD) to be more reliable as a proxy for RH at the OSR.
Genital Schistosomiasis in European Women
Authors: Catteau Xavier , Fakhri Anass , Albert Valérie , Doukoure Brahima , Noël Jean-Christophe
Published: June 2011

Female genital schistosomiasis (FGS) is an isolated chronic form of schistosomiasis.
Although most infections occur in residents of endemic areas, it has been clearly documented that brief freshwater exposure is sufficient to establish infection; thus, travellers may also be infected. The clinical manifestations of FGS are nonspecific, and lesions may mimic any neoplastic or infectious process in the female genital tract. It is important to take a careful history and physical examination, making sure to consider travel history in endemic areas. The diagnosis is confirmed by microscopy with egg identification or by serology. The standard of care for treatment is a single dose of oral praziquantel which avoids complications and substantial morbidity. Herein, we report a rare and original case of FGS in a European woman.
Uzzah’s Rebellion
Authors: Haase Ingrid M.
Published: June 2011

After David had freed Israelite soil from the Philistine
menace, he was able to move the Ark to a more appropriate place from Abinadab's
dwelling. He wanted it in Jerusalem, his new capital, where he needed a focal
point for the Yahwistic portion of his subjects in order to counterbalance the
Jebusite symbols of the city. Some of the priests who had been associated with
the Ark throughout the generations had misgivings. Not that the Ark had to go
back to Shiloh but neither did they want it sequestered in Jerusalem and become
part of the local cult there. So during David's triumphal progress, when they
came to a place, which was acceptable according to Israelite theology of the
time, the guardians of the Ark tried to retain it there. It is not certain what
happened next, because each sentence of the various passages is obscure in its
structure and wording, but the chief of the priestly contingent dies. Eventually
this occurrence gets to be interpreted as divine intervention in favour of
David's scheme. Initially though, the incident does upset David enough for him
to abandon his plans. He deposits the sacred object in the first house that he
comes to, and it is only after he receives assurances from the remainder of the
population, that he resumes his first ambition and he brings the Ark into
Jerusalem . The name of the place though, Perez-uzzah, remains a constant
reminder to David that a break had been made in his strength, his, David's,
power. David was never able to overcome this breach, and neither was his son
Solomon.
Shalmaneser III and the Levantine States: The “Damascus
Coalition Rebellion”
Authors: Grayson A. Kirk
Published: June 2011

This article serves to promote the interaction between
biblical scholars and archaeologists as well as other specialists in ancient
Near Eastern Studies. It discusses the Western policy begun by Shalmaneser III
and its impact in the Levant in general and Israel and Judah in particular. The
Assyrians had great knowledge of, and interest in, foreign lands, their
cultures, economies, and languages. It is hard to believe that they did not,
with their disciplined structure and extensive knowledge of the world around
them, have long-range plans to which the aims of the annual campaigns, barring
emergencies, adhered.
A Rejoinder to A. Brenner, “Regulating ‘sons’ and ‘daughters’
in the Torah and in Proverbs: Some Preliminary Insights”
Authors: Landy Francis
Published: June 2011

Some comments on A. Brenner, "Regulating ‘Sons’ and
‘Daughters’ in the Torah and in Proverbs: Some Preliminary Insights."
New Studies in Chronicles: A Discussion of Two
Recently-Published Commentaries
Authors: Knowles Melody D. , Mitchell Christine , Baltzer Klaus , Ben Zvi Ehud , Schweitzer Steven J. , Wright John W. , Knoppers Gary N. , Mackenzie Steven L.
Published: June 2011

Long considered derivative and hopelessly ideological, the
book of Chronicles is re-engaging the scholarly community, as noted by a recent
spate of articles and commentaries. This article presents a panel discussion on
two of these commentaries written by Steven L. McKenzie and Gary N. Knoppers.
The original discussion was held in Philadelphia (Nov. 20, 2005), during a
session of the Chronicles-Ezra-Nehemiah Section of the Society of Biblical
Literature. Included are the presentations of Ehud Ben Zvi, John Wright, Steven
James Schweitzer and Klaus Baltzer, as well as the responses from McKenzie and
Knoppers. In addition, this article includes a review of Knoppers’ commentary by
Christine Mitchell.