bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct current dielectrophoretic simulation of proteins using an array of circular insulating posts
Authors: Ivory Cornelius F. , Srivastava Soumya K. 
Published: November 2012

AbstractThis paper presents a mathematical model for the manipulation of proteins using insulator‐based dielectrophoresis (iDEP) and direct current (DC) electric fields. Simulations via COMSOL v4.1 Multiphysics® software are implemented to study the response of moderately sized proteins on a lab‐on‐a‐chip platform. The geometry of the device is incorporated in a model that solves current and mass conservation equations within an array of circular insulating silicon posts embedded in a channel. Both micro‐ and nano‐scale geometries are utilized to investigate the protein concentration distributions in the iDEP device. Our results indicate that the trapping of proteins is independent of the scale with respect to the geometry of a device as long as the applied electric field remains constant. DC voltage dependency on concentration distributions has also been explored in both micro‐ and nano‐scale device geometries. To achieve DEP trapping of the proteins, nano‐scale geometry is a better selection, as the voltage necessary to generate the required electric field (2.5 MV/cm) is 105× lower compared with the voltage required to generate the same field in the micro‐scale device.
Variations in multiscale curvature distribution and signatures of LiDAR DTM errors
Authors: Sofia Giulia , Pirotti Francesco , Tarolli Paolo 
Published: November 2012

ABSTRACTThe development of high resolution LiDAR digital terrain models (DTMs) has enabled the exploration of the statistical signature of morphology on curvature distributions. This work analyzes Minimum Curvature distributions to identify the statistical signature of two types of LiDAR‐DTM errors (outliers and striping artifacts) in the derived estimates, rather than morphology itself. The analysis shows the importance of modeling these errors correctly, in relation to the scale of analysis and DTM resolution, in order to have reliable curvature estimates. Nine DTMs of different morphological areas are considered, and grouped into a training dataset (without errors) and a test dataset (with errors). In the training dataset, the original DTMs are considered as true values; errors are then applied to these data. Minimum Curvature is computed at multiple scales from each DTM: changes in curvature distributions due only to morphology and scale are characterized from the original data; error effects are then identified from the datasets with simulated errors, and validated against the test dataset. The analysis shows that outliers and striping artifacts can be realistically simulated by heavily left tailed distributions. For DTMs without errors, the scale‐dependent change in curvature distribution is primarily controlled by real morphology. When DTMs include errors, curvature distributions become controlled by these errors, whose propagation depends on error distribution, error spatial correlation, and the scale of analysis. This study shows that the curvature distributions are impacted upon differently by striping artifacts and outliers, and that these are clearly distinguishable from the signal of morphological features: a scale‐dependent change in curvature distribution can therefore be interpreted as the signature of these specific errors, rather than morphology. Copyright © 2012 John Wiley & Sons, Ltd.
Influence of global climate change on chemical fate and bioaccumulation: The role of multimedia models
Authors: Gouin Todd , Armitage James M. , Cousins Ian T. , Muir Derek C.G. , Ng Carla A. , Reid Liisa , Tao Shu 
Published: November 2012

Abstract
Multimedia environmental fate models are valuable tools for investigating potential changes associated with global climate change, particularly because thermodynamic forcing on partitioning behavior as well as diffusive and nondiffusive exchange processes are implicitly considered. Similarly, food-web bioaccumulation models are capable of integrating the net effect of changes associated with factors such as temperature, growth rates, feeding preferences, and partitioning behavior on bioaccumulation potential. For the climate change scenarios considered in the present study, such tools indicate that alterations to exposure concentrations are typically within a factor of 2 of the baseline output. Based on an appreciation for the uncertainty in model parameters and baseline output, the authors recommend caution when interpreting or speculating on the relative importance of global climate change with respect to how changes caused by it will influence chemical fate and bioavailability. Environ. Toxicol. Chem. 2013;32:20–31. © 2012 SETAC
SPH for 3D floating bodies using variable mass particle distribution
Authors: Omidvar Pourya , Stansby Peter K. , Rogers Benedict D. 
Published: November 2012

SUMMARYA floating body with substantial heave motion is a challenging fluid–structure interaction problem for numerical simulation. In this paper we develop SPH in three dimensions to include variable particle mass distribution using an arbitrary Lagrange–Eulerian formulation with an embedded Riemann solver. A wedge or cone in initially still water is forced to move with a displacement equal to the surface elevation of a focused wave group. A two‐dimensional wedge case is used to evaluate two forms of repulsive‐force boundary condition on the body; the force depending on the normal distance from the object surface produced closer agreement with the experiment. For a three‐dimensional heaving cone the comparison between SPH and experiment shows excellent agreement for the force and free surface for motion with low peak spectral frequencies while for a higher peak frequency the agreement is reasonable in terms of phase and magnitude, but a small discrepancy appears at the troughs in the motion. Capturing the entire three‐dimensional flow field using an initially uniform particle distribution with sufficiently fine resolution requires an extremely large number of particles and consequently large computing resource. To mitigate this issue, we employ a variable mass distribution with fine resolution around the body. Using a refined mass distribution in a preselected area avoids the need for a dynamic particle refinement scheme and leads to a computational speedup of more than 600% or much improved results for a given number of particles. SPH with variable mass distribution is then applied to a single heaving‐float wave energy converter, the ‘Manchester Bobber’, in extreme waves and compared with experiments in a wave tank. The SPH simulations are presented for two cases: a single degree‐of‐freedom system with motion restricted to the vertical direction and with general motion allowing six degrees‐of‐freedom. The motion predicted for the float with general motion is in much closer agreement with experimental data than the vertically constrained system. Using variable particle mass distribution is shown to produce close agreement with a computation time 20% of that required with a uniformly fine resolution. Copyright © 2012 John Wiley & Sons, Ltd.
Electrocatalytic Oxidation of Formic Acid at Pt Modified Electrodes: Substrate Effect of Unsintered Au Nano‐Structure
Authors: Zhou R. , Yue R. , Jiang F. , Du Y. , Yang P. , Wang C. , Xu J. 
Published: November 2012

AbstractA Pt‐modified Au catalyst featured with novel layered structures and ultra‐low Pt loading has been designed and electrochemically fabricated on a glassy carbon (GC) electrode. SEM characterization suggests that as‐formed Pt/Au/GC electrode grows in a Stranski–Krastanov mode, resulting in a nearly ideal layered structure with Au at the inner layer and Pt at the outer layer. The electrocatalytic activity of the synthesized Pt/Au/GC electrode towards formic acid electrooxidation was studied, and comparative experiments with other modified electrodes (i.e., Pt/GC, Pt/Au, and Pt/Pt) were also conducted. As a result, the electrocatalytic activity of the outer‐layered Pt depends significantly on the intrinsic properties of the substrates. The prepared Pt/Au/GC electrode with Au nanoparticles modified GC as the substrate shows remarkable catalytic activity for the formic acid oxidation, much higher than that of its counterparts, Pt/GC, Pt/Au, and Pt/Pt electrodes. Additionally, the measured electrochemical impedance spectra indicate that the charge‐transfer resistance for formic acid electrooxidation on Pt/Au/GC electrode is smaller than that on other Pt modified electrodes.
The Interaction of Noble Metal With La1–xSrxMnO3 (001) Surface and Catalytic Role for Oxygen Adsorption: A Density Functional Theory Study
Authors: Zhou Y. , Lü Z. , Wei B. , Zhu X. , Yang D. , Jiang W. , Su W. 
Published: November 2012

AbstractAdsorption mechanisms of noble metals (Ag, Pd, Pt) on MnO2‐terminated (001) surface and their catalytic role for oxygen adsorption have been investigated using the first‐principles density functional theory calculations. The analysis of the adsorption energies reveals that the energetically favorable configuration for Ag and Pd adsorption is at the O site, whereas one for Pt adsorption is at the Mn site. Pt atom exhibits the largest adsorption energy, followed by Pd and Ag atoms. Both bond population and PDOS (partial density of states) analysis confirm the formation of adatom–O–Mn bonds. Adsorption is accompanied by a charge transfer between adatoms and surface atoms. Significantly, we predict that the order on the increase of O2 adsorption energy follows the Pd > Ag > Pt due to pre‐adsorbed noble metal atoms. The calculated bond length and bond population of O2 molecule demonstrate that pre‐adsorbed noble metal atoms facilitates O2 molecule dissociate to O atoms, thus contributing to the surface oxygen diffusion process. Our calculations identify an important catalytic role of noble metal in LSM‐based catalysts, which may improve electrochemical performance for SOFCs cathodes.
Proton and Protonic Species: The Hidden Face of Solid State Chemistry. How to Measure H‐Content in Materials?
Authors: Colomban Ph. 
Published: November 2012

AbstractThe first objectives of Chemistry are the description of the reactions and the determination of the composition of each compound involved in a process. Solid State Chemistry tries to establish the composition and the structure, the (micro/nano)structure as well as the relationship between composition, structure, and material properties. In the case of Hydrogen element, most of the literature data do not follow this approach: the contents of protons and associated protonic species are rarely measured. Based on the examples of proton conducting materials with different water content: (i) high (sol–gel materials), (ii) medium (polyaniline (PANI) polymer and salts), and (iii) anhydrous (protonated perovskites), we will discuss the main methods (TGA, thermal expansion, infrared and Raman spectroscopy, incoherent (elastic, quasi‐ and in‐elastic) and coherent neutron scattering, neutronography, NRA, RBS/ERDA, ERCS, etc.) able to detect/measure the proton content and/or to identify the nature of the protonic species and their interaction with the host framework: hydroxyl ion, “free” proton, physi/chemi‐sorbed water, strong H‐bonded water, proton hydrates, aquo‐hydroxycarbonates, etc. Emphasis is given to the difficulties encountered for the identification and the quantification of protonic species and the way to overcome them, in particular the discrimination between the surface and bulk moieties.
Performance Improvement of Wave‐Like PEMFC Stack with Compound Membrane Electrode Assembly
Authors: Yi P. Y. , Peng L. F. , Lai X. M. , Lin Z. Q. , Ni J. 
Published: November 2012

AbstractThe novel architecture of wave‐like proton exchange membrane fuel cell (PEMFC) stack developed in our previous work achieved peak volumetric power density and specific power of 2,715.9 W L–1 and 2,157.9 W kg–1, respectively. However, there still existed perforated bipolar plates and the carbon fiber gas diffusion layer (GDL) was easy to cause damage during the fabrication process of undulate membrane electrode assembles (MEAs). In the present study, sintered stainless steel fiber felt (SSSFF) was employed to work as metallic GDL (MGDL) and bipolar plates simultaneously. Compound membrane electrode assembles (CMEAs) with serpentine and interdigitated flow channels were designed and fabricated using stamping process. A single cell with CMEA was assembled in house and the output performance was evaluated systemically. The results indicated that the peak volumetric power density and specific power of wave‐like PEMFC single with CMEA are 5,764.0 W L–1 and 4,693.5 W kg–1 respectively. This study achieved a significant performance improvement due to the concept of CMEA and may propose a possible means to meet the DOE's 2020 technical target that volumetric power density is 2,500 W L–1 and specific power is 2,000 W kg–1 for stack.
Stabilization of Sulfonated Aromatic Polymer (SAP) Membranes Based on SPEEK‐WC for PEMFCs
Authors: Fontananova E. , Brunetti A. , Trotta F. , Biasizzo M. , Drioli E. , Barbieri G. 
Published: November 2012

AbstractIn this work dense polymer electrolyte membranes (PEM) were prepared by casting and solvent evaporation from homogeneous solutions of the sulfonated derivative of an amorphous polyetheretherketone, known as SPEEK‐WC. In order to obtain stabilized PEMs, the SPEEK‐WC membranes were modified by following three different strategies: thermal annealing, chemical cross‐linking with a diamine and blending with Nafion ionomer. Various ex situ characterizations were carried out on the modified and reference SPEEK‐WC membranes, including: ion exchange capacity, proton conductivity, liquid water uptake, counter elastic index, chemical resistance in oxidative conditions, and gas permeability. The results indicated that the first two methodologies are able to increase hydrolytic and oxidative stability of the SPEEK‐WC membranes at a temperature higher than 100 °C.
Match criteria for human cell line authentication: Where do we draw the line?
Authors: Capes‐Davis Amanda , Reid Yvonne A. , Kline Margaret C. , Storts Douglas R. , Strauss Ethan , Dirks Wilhelm G. , Drexler Hans G. , MacLeod Roderick A.F. , Sykes Gregory , Kohara Arihiro , Nakamura Yukio , Elmore Eugene , Nims Raymond W. , Alston‐Roberts Christine , Barallon Rita , Los Georgyi V. , Nardone Roland M. , Price Paul J. , Steuer Anton , Thomson Jim , Masters John R.W. , Kerrigan Liz 
Published: November 2012

AbstractContinuous human cell lines have been used extensively as models for biomedical research. In working with these cell lines, researchers are often unaware of the risk of cross‐contamination and other causes of misidentification. To reduce this risk, there is a pressing need to authenticate cell lines, comparing the sample handled in the laboratory to a previously tested sample. The American Type Culture Collection Standards Development Organization Workgroup ASN‐0002 has developed a Standard for human cell line authentication, recommending short tandem repeat (STR) profiling for authentication of human cell lines. However, there are known limitations to the technique when applied to cultured samples, including possible genetic drift with passage. In our study, a dataset of 2,279 STR profiles from four cell banks was used to assess the effectiveness of the match criteria recommended within the Standard. Of these 2,279 STR profiles, 1,157 were grouped into sets of related cell lines—duplicate holdings, legitimately related samples or misidentified cell lines. Eight core STR loci plus amelogenin were used to unequivocally authenticate 98% of these related sets. Two simple match algorithms each clearly discriminated between related and unrelated samples, with separation between related samples at ≥80% match and unrelated samples at <50% match. A small degree of overlap was noted at 50–79% match, mostly from cell lines known to display variable STR profiles. These match criteria are recommended as a simple and effective way to interpret results from STR profiling of human cell lines.
Geographical distribution and oncogenic risk association of human papillomavirus type 58 E6 and E7 sequence variations
Authors: Chan Paul K.S. , Zhang Chuqing , Park Jong‐Sup , Smith‐McCune Karen K. , Palefsky Joel M. , Giovannelli Lucia , Coutlée Francois , Hibbitts Samantha , Konno Ryo , Settheetham‐Ishida Wannapa , Chu Tang‐Yuan , Ferrera Annabelle , Alejandra Picconi María , De Marco Federico , Woo Yin‐Ling , Raiol Tainá , Piña‐Sánchez Patricia , Bae Jeong‐Hoon , Wong Martin C.S. , Chirenje Mike Z. , Magure Tsitsi , Moscicki Anna‐Barbara , Fiander Alison N. , Capra Giuseppina , Young Ki Eun , Tan Yi , Chen Zigui , Burk Robert D. , Chan Martin C.W. , Cheung Tak‐Hong , Pim David , Banks Lawrence 
Published: November 2012

AbstractHuman papillomavirus (HPV) 58 accounts for a notable proportion of cervical cancers in East Asia and parts of Latin America, but it is uncommon elsewhere. The reason for such ethnogeographical predilection is unknown. In our study, nucleotide sequences of E6 and E7 genes of 401 HPV58 isolates collected from 15 countries/cities across four continents were examined. Phylogenetic relationship, geographical distribution and risk association of nucleotide sequence variations were analyzed. We found that the E6 genes of HPV58 variants were more conserved than E7. Thus, E6 is a more appropriate target for type‐specific detection, whereas E7 is more appropriate for strain differentiation. The frequency of sequence variation varied geographically. Africa had significantly more isolates with E6‐367A (D86E) but significantly less isolates with E6‐203G, ‐245G, ‐367C (prototype‐like) than other regions (p ≤ 0.003). E7‐632T, ‐760A (T20I, G63S) was more frequently found in Asia, and E7‐793G (T74A) was more frequent in Africa (p < 0.001). Variants with T20I and G63S substitutions at E7 conferred a significantly higher risk for cervical intraepithelial neoplasia grade III and invasive cervical cancer compared to other HPV58 variants (odds ratio = 4.44, p = 0.007). In conclusion, T20I and/or G63S substitution(s) at E7 of HPV58 is/are associated with a higher risk for cervical neoplasia. These substitutions are more commonly found in Asia and the Americas, which may account for the higher disease attribution of HPV58 in these areas.
Cardioprotection by acetylcholine: A novel mechanism via mitochondrial biogenesis and function involving the PGC‐1α pathway
Authors: Sun Lei , Zhao Mei , Yu Xiao‐Jiang , Wang Hao , He Xi , Liu Jian‐Kang , Zang Wei‐Jin 
Published: November 2012

AbstractMitochondrial biogenesis disorders appear to play an essential role in cardiac dysfunction. Acetylcholine as a potential pharmacologic agent exerts cardioprotective effects. However, its direct action on mitochondria biogenesis in acute cardiac damage due to ischemia/reperfusion remains unclear. The present study determined the involvement of mitochondrial biogenesis and function in the cardiopotection of acetylcholine in H9c2 cells subjected to hypoxia/reoxygenation (H/R). Our findings demonstrated that acetylcholine treatment on the beginning of reoxygenation improved cell viability in a concentration‐dependent way. Consequently, acetylcholine inhibited the mitochondrial morphological abnormalities and caused a significant increase in mitochondrial density, mass, and mitochondrial DNA (mtDNA) copy number. Accordingly, acetylcholine enhanced ATP synthesis, membrane potentials, and activities of mitochondrial complexes in contrast to H/R alone. Furthermore, acetylcholine stimulated the transcriptional activation and protein expression of peroxisome proliferator‐activated receptor co‐activator 1 alpha (PGC‐1α, the central factor for mitochondrial biogenesis) and its downstream targets including nuclear respiration factors and mitochondrial transcription factor A. In addition, acetylcholine activated phosphorylation of AMP‐activated protein kinase (AMPK), which was located upstream of PGC‐1α. Atropine (muscarinic receptor antagonist) abolished the favorable effects of acetylcholine on mitochondria. Knockdown of PGC‐1α or AMPK by siRNA blocked acetylcholine‐induced stimulating effects on mtDNA copy number and against cell injury. In conclusion, we suggested, acetylcholine as a mitochondrial nutrient, protected against the deficient mitochondrial biogenesis and function induced by H/R injury in a cellular model through muscarinic receptor‐mediated, AMPK/PGC‐1α‐associated regulatory program, which may be of significance in elucidating a novel mechanism underlying acetylcholine‐induced cardioprotection. J. Cell. Physiol. 228: 1238–1248, 2013. © 2012 Wiley Periodicals, Inc.
Efficient nonviral gene therapy with FasL and Del1 fragments in mice
Authors: Kitano Hisataka , Mamiya Atsushi , Kokubun Shinichiro , Hidai Chiaki 
Published: November 2012

AbstractBackgroundThe expression of FasL in cancer cells is currently being explored as a potential cancer therapy. Because high levels of FasL are necessary for effective treatment, current methods typically rely on the use of highly efficient viral vectors. However, because viral vector‐based gene therapy is associated with certain risks, the development of effective nonviral routes for gene delivery would be useful. The present study aimed to improve FasL gene therapy with a nonviral vector by taking advantage of the E3 and C1 domains of Del1 protein, which induces apoptosis and localizes to the extracellular matrix.MethodsMouse explanted tumors derived from a human oral squamous cell carcinoma cell line, SCCKN, were treated with plasmids encoding FasL (pFasL), E3C1 (pE3C1), and a fusion of FasL and E3C1 (pFasL‐E3C1). The plasmids were injected locally every 7 days along with a transfection reagent, Jet‐PEI (PolyPlus‐transfection, San Marcos, CA, USA).ResultsAll mice treated with a negative control plasmid or pFasL died within 49 days. By contrast, 83% of mice treated with pFasL‐E3C1 survived longer than 49 days. Histochemical studies revealed that the fusion protein is localized to the stroma and induces apoptosis in stromal cells and adjacent parenchymal cells.ConclusionsThe results obtained in the present study suggest that the protein deposition‐based approach described, which makes use of the E3 and C1 domains of Del1, could comprise a novel method for cancer gene therapy with nonviral vectors. Copyright © 2012 John Wiley & Sons, Ltd.
The importance of lag screw position for the stabilization of trochanteric fractures with a sliding hip screw: A subject‐specific finite element study
Authors: Goffin Jérôme M. , Pankaj Pankaj , Simpson A. Hamish 
Published: November 2012

AbstractUsing finite element analysis, we compared the biomechanical performance of a CT scan‐based three‐part trochanteric fracture model (31‐A2 in the AO classification) stabilized with a sliding hip screw for nine different positions of the lag screw (3 × 3 arrangement, from anterior to posterior and from inferior to superior). Our results showed that the volume of bone susceptible to yielding in the head and neck region is the lowest for inferior positions and increases as the lag screw is moved superiorly. Overall, for this specific subject, the models less likely to lead to cut‐out are the ones corresponding to inferior middle and inferior posterior positions of the lag screw. In our study, the tip‐apex distance (TAD) was anti‐correlated with the risk of cut‐out, as quantified by the volume of bone susceptible to yielding, which suggests that a TAD >25 mm cannot be considered to be an accurate predictor of lag screw cut‐out. Further clinical studies investigating lag screw cut‐out should attempt to find more reliable predictors of cut‐out that should better reflect the biomechanics and subject‐specificity of the femoral head. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 596–600, 2013