bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acceleration of the GAMESS‐UK electronic structure package on graphical processing units
Authors: Wilkinson Karl A. , Sherwood Paul , Guest Martyn F. , Naidoo Kevin J. 
Published: May 2011

AbstractThe approach used to calculate the two‐electron integral by many electronic structure packages including generalized atomic and molecular electronic structure system‐UK has been designed for CPU‐based compute units. We redesigned the two‐electron compute algorithm for acceleration on a graphical processing unit (GPU). We report the acceleration strategy and illustrate it on the (ss|ss) type integrals. This strategy is general for Fortran‐based codes and uses the Accelerator compiler from Portland Group International and GPU‐based accelerators from Nvidia. The evaluation of (ss|ss) type integrals within calculations using Hartree Fock ab initio methods and density functional theory are accelerated by single and quad GPU hardware systems by factors of 43 and 153, respectively. The overall speedup for a single self consistent field cycle is at least a factor of eight times faster on a single GPU compared with that of a single CPU. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
The syntheses and in vitro biotransformation studies of [14C]apixaban, a highly potent, selective, efficacious and orally bioavailable inhibitor of blood coagulation Factor Xa
Authors: Maxwell Brad D. , Tran Scott B. , Chen Shiang‐Yuan , Zhang Donglu , Chen Bang‐Chi , Zhang Huiping , Bonacorsi Samuel J. 
Published: May 2011

AbstractApixaban is a potent inhibitor of blood coagulation Factor Xa in the late stages of development. [14C]apixaban was synthesized with the 14C label in the two different lactam ring systems within the molecule for various in vitro and in vivo metabolism studies. A nine‐step synthesis of [14C]apixaban, 10, with the label in the central lactam ring was completed in 14% overall yield. A second synthesis of [14C]apixaban, 14, with the 14C label in the outer lactam ring was completed in three steps in a 14% overall yield. No significant differences were observed between the metabolite profiles of 10 and 14, [14C]apixaban, from both rat and human hepatocyte or microsomal incubations. Copyright © 2011 John Wiley & Sons, Ltd.
Prevalence and clinical significance of hepatitis D virus co‐infection in patients with chronic hepatitis B in Korea
Authors: Kim Hyoung Su , Kim Sung Jun , Park Hye Won , Shin Woon Geon , Kim Kyung Ho , Lee Jin Heon , Kim Hak Yang , Jang Myoung Kuk 
Published: May 2011

AbstractHepatitis D virus (HDV) infection can cause severe acute and chronic liver disease in patients infected with hepatitis B virus (HBV). Despite the significant decline in the global HDV infection, it remains a major health concern in some countries. This study aimed to investigate the prevalence and clinical features of HDV co‐infection in patients with chronic HBV infection in Korea, where HBV infection is endemic. Nine hundred forty patients [median age, 48 (18–94) years; men, 64.5%] infected chronically with HBV were enrolled consecutively. All patients who were positive for hepatitis B surface antigen (HBsAg) for at least 6 months and were tested for anti‐HDV. A portion of the HDV delta antigen was amplified, sequenced, and subjected to molecular and phylogenetic analysis using sera from the patients who were anti‐HDV positive. Clinical features and virologic markers were evaluated. Inactive HBsAg carriers, chronic hepatitis B, cirrhosis and hepatocellular carcinoma accounted for 29.5%, 44.7%, 17.9%, and 8.0%, respectively. Only three patients were positive for anti‐HDV, corresponding to a 0.32% positive rate. All patients who were positive for anti‐HDV were inactive HBsAg carriers. HDV RNA could be amplified by PCR from the sera of two patients. Phylogenetic analysis showed that both carried HDV genotype 1. In conclusion, the prevalence of HDV infection is very low (0.32%) in Korea. All HDVs were genotype 1 and detected in inactive HBsAg carriers. Therefore, HDV co‐infection may not have a significant clinical impact in Korean patients with chronic HBV infection. J. Med. Virol. 83:1172–1177, 2011. © 2011 Wiley‐Liss, Inc.
Reversible inhibition of hydrogen peroxide elimination by calcium in brain mitochondria
Authors: Tretter Laszlo , Biagioni Angeli Emanuela , Ardestani Mohammad Reza , Goracci Gianfrancesco , Adam‐Vizi Vera 
Published: May 2011

AbstractIn the present work, the Ca2+ dependence of mitochondrial H2O2 elimination was investigated. Mitochondria isolated from guinea pig brain were energized by glutamate and malate and incubated with micromolar concentrations of Ca2+ in the presence of ADP, preventing permeability transition pore formation. After the completion of Ca2+ uptake, mitochondria were challenged with H2O2 (5 μM), then at various time points residual H2O2 was determined using the Amplex red method and compared with that in mitochondria incubated with H2O2 without Ca2+ addition. Dose‐dependent inhibition of H2O2 elimination by Ca2+ was detected, which was prevented by the Ca2+‐uptake inhibitor Ru 360. Stimulation of Ca2+ release from Ca2+ ‐loaded mitochondria by a combined addition of Ru 360 and Na+ decreased the Ca2+‐evoked inhibition of H2O2 removal. After Ca2+ uptake (50 μM), mitochondrial aconitase activity was found to be decreased, which was partially attributable to the impaired elimination of endogenously produced reactive oxygen species. We found that the effects of Ca2+ and H2O2 on the activity of aconitase were additive. These results confirm that Ca2+ inhibits elimination of H2O2 in mitochondria and demonstrate that this effect is concentration dependent and reversible. The phenomenon described here can play a role in the modulation of ROS handling under conditions involving excessive cellular Ca2+ load. © 2011 Wiley‐Liss, Inc.
The “B Space” of mitochondrial phosphorylation
Authors: Chinopoulos Christos 
Published: May 2011

AbstractIt was recently shown that, in progressively depolarizing mitochondria, the F0‐F1 ATP synthase and the adenine nucleotide translocase (ANT) may change directionality independently from each other (Chinopoulos et al. [2010] FASEB J. 24:2405). When the membrane potentials at which these two molecular entities reverse directionality, termed reversal potential (Erev), are plotted as a function of matrix ATP/ADP ratio, an area of the plot is bracketed by the Erev_ATPase and the Erev_ANT, which we call “B space”. Both reversal potentials are dynamic, in that they depend on the fluctuating values of the participating reactants; however, Erev_ATPase is almost always more negative than Erev_ANT. Here we review the conditions that define the boundaries of the “B space”. Emphasis is placed on the role of matrix substrate‐level phosphorylation, because during metabolic compromise this mechanism could maintain mitochondrial membrane potential and prevent the influx of cytosolic ATP destined for hydrolysis by the reversed F0‐F1 ATP synthase. © 2011 Wiley‐Liss, Inc.
An insight into the mechanism of CEC separation of template analogues on a norepinephrine‐imprinted monolith
Authors: Huang Bao‐Yu , Chen Yu‐Cheng , Liu Chuen‐Ying 
Published: May 2011

AbstractA monolith molecularly imprinted polymer (MIP) column was prepared from template (−)‐norepinephrine, functional monomer (itaconic acid), and a cross‐linker (either ethylene glycol dimethacrylate or divinylbenzene) in porogen N,N‐dimethylformamide. Understanding the molecular recognition of a template using an MIP seems feasible. However, it is hard to explain the recognition properties of their analogues on an MIP. The separation mechanism was investigated with the addition of charged surfactants, native and derivatised β‐cyclodextrin (β‐CD), achiral crown ether, etc. to determine the retention behaviour of the template analogues. The addition of organic modifiers and the adjustment of separation conditions were used to manipulate the selectivity. No chiral recognition was observed under most of the test conditions except the experiment with the charged β‐CD on the divinylbenzene‐MIP column. The different experimental conditions led to differences in the mobilities of the analytes and resulted in remarkable enantiomeric separation of the template. We confirmed the presence of mixed‐mode selectivity of the stationary phase based on hydrogen bonding, hydroelectric and hydrophobic interactions, and the electrophoretic mode.
Method for removing hypopharyngeal salivary bypass tubes
Authors: Kejner Alexandra E. , Rosenthal Eben L. 
Published: May 2011

AbstractObjective:To describe a novel method for the removal of the salivary bypass tube (SBT) that precludes the need for extraction under general anesthesia.Study Design:Retrospective case series.Methods/Technique:Patients who had undergone laryngectomy/laryngopharyngectomy with subsequent development of pharyngocutaneous fistula and intraoperative placement of a salivary bypass tube were included in this series. The tubes were removed at the bedside or in clinic utilizing a Fogarty‐type method over a Foley catheter.Results:Three patients underwent removal of hypopharyngeal salivary bypass tubes 1 to 2 weeks after placement. Inflation of the Foley catheter within the lumen of the salivary bypass tube facilitated successful removal without the need for additional procedures. All three patients required only topical anesthetic and tolerated the procedure with minimal discomfort.Conclusions:Compared to current methods, this technique is cost‐effective and time‐efficient while not compromising patient safety or comfort. Laryngoscope, 2011
Chain‐Length‐Dependent Termination in Radical Polymerization of Acrylates
Authors: Barth Johannes , Buback Michael , Russell Gregory T. , Smolne Sebastian 
Published: May 2011

AbstractThe technique of SPPLP EPR, which is single‐pulse pulsed‐laser polymerization (SPPLP) in conjunction with electron paramagnetic resonance (EPR) spectroscopy, is used to carry out a detailed investigation of secondary (chain‐end) radical termination of acrylates. Measurements are performed on methyl acrylate, n‐butyl acrylate, and dodecyl acrylate in bulk and in toluene solution at −40 °C. The reason for the low temperature is to avoid formation of mid‐chain radicals (MCRs), a complicating factor that has imparted ambiguity to the results of previous studies of this nature. Consistent with these previous studies, composite‐model behavior for chain‐length‐dependent termination (CLDT) rate coefficients, $k_{{\rm t}}^{i,i} $, is found in this work. However, lower and more reasonable values of αs, the exponent for variation of $k_{{\rm t}}^{i,i} $ at short chain lengths, are found in the present study. Most likely this is because of the absence of MCRs, thereby validating the methodology of this work. Family‐type termination behavior is observed, with the following average parameter values adequately describing all results, regardless of acrylate or the presence of toluene: αs  = 0.79, αl = 0.21 (long chains) and ic ≈ 30 (crossover chain length). All indications are that these values carry over to termination of acrylate chain‐end radicals at higher, more practical temperatures. Further, these values largely make sense in terms of what is understood about the physical meaning of the parameters. Variation of the rate coefficient for termination between monomeric radicals, $k_{{\rm t}}^{{\rm 1,1}} $, is found to be well described by the simple Smoluchowski and Stokes–Einstein equations. This allows easy prediction of $k_{{\rm t}}^{{\rm 1,1}} $ for different alkyl acrylates, solvent, and temperature. Through all this the unrivalled power of SPPLP EPR for measuring and understanding (chain‐length‐dependent) termination rate coefficients shines through. magnified image
Morphology Development in Relation to the Ternary Phase Diagram of Biodegradable PDLLA/PCL/PEO Blends
Authors: Buddhiranon Sasiwimon , Kim Namil , Kyu Thein 
Published: May 2011

AbstractThe morphology phase diagram of biodegradable polymer blends of PDLLA, PCL, and PEO is presented and discussed. The phase diagram of PCL/high‐molecular‐weight PDLLA mixtures reveals an hour‐glass phase diagram. Upon lowering the molecular weight of PDLLA, a combined LCST/UCST develops that is intersected by the melting transition curve of PCL. The observed liquid/liquid phase separation and crystal/isotropic phase transition are compared with the theoretical liquidus/solidus curves obtained by solving the combined Flory‐Huggins and phase‐field free energies self‐consistently. A similar study is extended to the binary phase diagrams of PEO/PDLLA and PCL/PEO. Of particular interest is that the prism‐type phase diagram of the ternary blends provides a complete description of the overall phase behavior. magnified image
Tailoring the Degree of Polymerization of Low Molecular Weight Cellulose
Authors: Meiland Marcel , Liebert Tim , Heinze Thomas 
Published: May 2011

AbstractThe degradation of cellulose to lmw samples with $\overline {DP} _{{\rm w}} $ varying from 15 to 130 is investigated. Cellulose samples prepared from the hydrolysis of regenerated cellulose fibers in dilute HCl possess $\overline {DP} _{{\rm w}} $ = 50. Applying homogenous degradation of microcrystalline cellulose in H3PO4 at RT for 3 weeks, samples with $\overline {DP} _{{\rm w}} $ = 35 and a PDI of 1.58 are obtained. Decreasing the hydrolysis temperature to 8 °C results in lmw cellulose with $\overline {DP} _{{\rm w}} $ > 70. Fractionation in DMA/LiCl provides samples with $\overline {DP} _{{\rm w}} $ = 12 to 130, together with a narrow molecular weight distribution. Detailed structural analysis by 2D NMR spectroscopy reveals that the prepared lmw celluloses are suitable as mimics for cellulose. magnified image
Extrusion Foaming of Poly (lactic acid)/Soy Protein Concentrate Blends
Authors: Liu Bo , Jiang Long , Zhang Jinwen 
Published: May 2011

AbstractPoly(lactic acid) (PLA) and soy protein concentrate (SPC) were compounded using poly(2‐ethyl‐2‐oxazoline) as compatibilizer by twin‐screw extrusion, and the resulting blends were foamed by a chemical blowing agent (CBA) using the same extruder. Effects of foaming temperature and CBA content on cell density and foam density were investigated. Polymeric methylene diphenyl diisocyanate (pMDI) as a co‐compatibilizer was added prior to foaming extrusion and its effects on foam morphology and properties were also studied. The results showed that cell density and foam density were greatly influenced by foaming temperature and CBA content. Using the strong interfacial modifier pMDI in PLA/SPC blends resulted in high‐cell density and low‐foam density when CBA concentration was low. magnified image
Self‐supporting Polymer from a POSS Derivative
Authors: Cheng Chih‐Chia , Yen Ying‐Chieh , Chang Feng‐Chih 
Published: May 2011

AbstractA new polyhedral oligomeric silsesquioxane macromer, octakis[N‐(6‐aminopyridin‐2‐yl)undecanamide‐10‐dimethyl‐siloxy]silsesquioxane (POSS‐C11‐Py), containing eight diaminopyridine arms, is able to self‐assemble to form a physically crosslinked polymer‐like structure with good mechanical properties (tensile strength = 46.1 MPa, tensile modulus = 0.58 GPa, elongation = 49.3%) through quadruple hydrogen bonding interactions between these arms. POSS‐C11‐Py is the first organic/inorganic supermolecule possessing polymer‐like mechanical properties as a result of self‐complementary interactions, providing a potential route toward the design and fabrication of polymer‐like supramolecular materials. magnified image
Three dimensional modelling of fibrous materials and experimental validation
Authors: Curto J.M.R. , Conceição E.L.T. , Portugal A.T.G. , Simões R.M.S. 
Published: May 2011

AbstractThis article presents a computational model and some simulation results for fibrous materials such as paper. To obtain a better understanding of the influence of fibre properties on the paper structure a novel paper model was developed. This is a physically based model where paper is formed by the sequential deposition of individual fibres. The model intends to capture key papermaking fibre properties like morphology, flexibility, and collapse and process operations such as fibre deposition, network forming or densification. This model is a step forward in transverse paper modelling. In fact, it is a three dimensional model that includes the fibre microstructure, that is, lumen and fibre wall thickness, with a resolution up to 0.05 μm. To test the model validity and predictive capability, laboratory hand sheets were used to study the network formation of an office paper, mainly produced from Eucalyptus globulus bleached Kraft pulp. This paper was characterized via an experimental design that included factors such as raw material and beating degree. The resulting porous structure was characterized and the mechanical performance was assessed. The computational simulation was used to investigate the relative influence of fibre properties such as fibre flexibility, dimensions and collapsibility. The developed multiscale model gave realistic predictions and enabled us to link fibre microstructure and paper properties.
Experimental study of silicone‐epoxy dual adhesive joints for high temperature aerospace applications
Authors: Marques E.A.S. , Magalhães D.N.M. , da Silva L.F.M. 
Published: May 2011

AbstractAdhesive bonding is extensively used in aerospace applications. Some of the most important aerospace applications are in heat shields intended to protect metallic structures from extreme heat. Many heat shields are bonded with RTV silicone based adhesives, which have excellent resistance to high temperature but very low strength. This work proposes and studies three alternative configurations to these adhesive layers. One configuration with RTV silicone only (RTV106), one with only a high temperature epoxy (XN1244) and finally another configuration introducing both adhesives in the same joint (mixed joint). Experimental specimens and a testing device intended to simulate the loads on an actual heat shield were manufactured. These specimens were subjected to loading and tested until failure at both low and high temperatures. It was demonstrated that while the RTV silicone joints lose strength at 100°C, the epoxy and mixed joints are able to retain most of their strength. The mixed joint is also able to withstand large values of displacement at relatively high forces, indicating excellent capabilities at absorbing directed energy. The improvements and advantages deriving from the use of these alternative configurations are described and compared.
Tensile test of lead zirconate titanate (PZT)/Platinum (Pt) thin film
Authors: Park J.‐H. , Bae H.‐Y. , Oh Y.‐R. , Kim Y.‐J. , Kim H.Y. , Huh Y.‐H. 
Published: May 2011

AbstractThis paper presents the results of tensile tests for lead zirconate titanate (PZT)/Platinum (Pt) thin films of 2.15 μm thickness in atmospheric air at room temperature. An axial loading tester developed by the authors was used for the tests. The tester was equipped with a load cell with a maximum capacity of 0.5 N and a non‐contact position measuring system based on the principle of capacitance micrometry. Furthermore, the tester was equipped with a CCD (charge‐coupled device) system for measuring the displacement of the gage length. Specimens with three different widths (50, 100 and 150 μm) were fabricated to study the size (width of specimen) effects. The elastic moduli of the specimens with 50, 100 and 150 μm width were 72.8 ± 3.7, 75.0 ± 1.3, 73.3 ± 1.8 GPa, respectively. In addition, the ultimate tensile strength of the specimens with 50, 100 and 150 μm width were 263.4 ± 21.1, 238.6 ± 4.5, 221.1 ± 13.9 MPa, respectively. It was observed that the width of specimen has little effect on the elastic modulus of PZT/Pt thin films but has an effect on the ultimate tensile strength of PZT/Pt thin films and the ultimate tensile strength decreases as the width increases. It was assumed that the scatter in the ultimate tensile strength of 50 μm width was attributed to delamination of PZT/Pt layers before the fracture in the tensile test. The 0.2% offset yield strength could not be measured because the PZT/Pt thin film is very brittle.
Uric acid as a potential disease modifier in patients with multiple system atrophy
Authors: Lee Ji E. , Song Sook K. , Sohn Young H. , Lee Phil Hyu 
Published: May 2011

AbstractBackground:Recent studies have suggested that mitochondrial dysfunction and oxidative stress play a key role in the pathogenesis of multiple system atrophy.Methods:We evaluated the influence of serum uric acid levels on disease progression in 52 patients with multiple system atrophy using changes in the annualized Unified Multiple System Atrophy Rating Scale scores.Results:The mean annualized Unified Multiple System Atrophy Rating Scale changes were significantly lower in patients with the highest uric acid quartile compared with those with the lowest quartile (8.4 ± 5.1 vs 20.2 ± 16.0, P = .038). Serum uric acid levels had a significant negative correlation with the annualized Unified Multiple System Atrophy Rating Scale changes (r = −0.40, P = .004). Multiple linear regression analysis showed that only serum uric acid concentration was significantly correlated with the annualized Unified Multiple System Atrophy Rating Scale changes (β = −2.687, P = .011).Conclusions:These data suggest that serum uric acid may act as a potential disease modifier in multiple system atrophy. © 2011 Movement Disorder Society
Error analysis for hybrid Trefftz methods coupling traction conditions in linear elastostatics
Authors: Li Zi‐Cai 
Published: May 2011

AbstractFor linear elastostatics, the Lagrange multiplier to couple the displacement (i.e., Dirichlet) condition is well known in mathematics community, but the Lagrange multiplier to couple the traction (i.e., Neumann) condition is popular for elasticity problems by the Trefftz method in engineering community, which is called the Hybrid Trefftz method (HTM). However, there has not been any analysis for these Lagrange multipliers to couple the traction condition so far. New error analysis of the HTM for elasticity problems is explored in this paper, to derive error bounds with the optimal convergence rates. Numerical experiments are reported to support this analysis. The error analysis of the HTM for linear elastostatics is the main aim of this paper. In this paper, the collocation Trefftz method (CTM) without a multiplier is also introduced, accompanied with error analysis. Numerical comparisons are made for HTM and CTM using fundamental solutions (FS) and particular solutions (PS). The error analysis and numerical computations show that the accuracy of the HTM is equivalent to that of the CTM, but the stability of the CTM is good. For elasticity and other complicated problems, the simplicity of algorithms and programming grants the CTM a remarkable advantage. More numerical comparisons show that using PS is more efficient than using FS in both HTM and CTM. However, since the optimal convergence rates are the most important criterion in evaluation of numerical methods, the global performance of the HTM is as good as that of the CTM. The comparisons of HTM and CTM using FS and PS are the next aim of this article. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2011