bluuebunny/crossref_metadata_2025_split huggingface dataset:
The natural volume method (NVM): Presentation and application to shallow water inviscid flows
Authors: Ata R. , Soulaïmani A. , Chinesta F. 
Published: April 2008

AbstractIn this paper a fully Lagrangian formulation is used to simulate 2D shallow water inviscid flows. The natural element method (NEM), which has been used successfully with several solid and fluid mechanics applications, is used to approximate the fluxes over Voronoi cells. This particle‐based method has shown huge potential in terms of handling problems involving large deformations. Its main advantage lies in the interpolant character of its shape function and consequently the ease it allows with respect to the imposition of Dirichlet boundary conditions.In this paper, we use the NEM collocationally, and in a Lagrangian kinematic description, in order to simulate shallow water flows that are boundary moving problems. This formulation is ultimately shown to constitute a finite‐volume methodology requiring a flux computation on Voronoi cells rather than the standard elements, in a triangular or quadrilateral mesh. St Venant equations are used as the mathematical model. These equations have discontinuous solutions that physically represent the existence of shock waves, meaning that stabilization issues have thus been considered. An artificial viscosity deduced from an analogy with Riemann solvers is introduced to upwind the scheme and therefore stabilize the method. Some inviscid bidimensional flows were used as preliminary benchmark tests, which produced decent results, leading to well‐founded hopes for the future of this method in real applications. Copyright © 2008 John Wiley & Sons, Ltd.
Low‐affinity excitatory amino acid uptake in hippocampal astrocytes: A possible role of Na+/dicarboxylate cotransporters
Authors: Talgøy Holten Aleksander , Christian Danbolt Niels , Keiko Shimamoto , Vidar Gundersen 
Published: April 2008

AbstractThe excitatory amino acid transporters (EAATs) underlie the so‐called “high affinity” uptake of glutamate, which is well characterized. In contrast, the “low‐affinity” uptake of glutamate remains poorly defined, and it has been discussed whether it may represent a mere in vitro artifact. Here we have visualized “low‐affinity” excitatory amino acid uptake sites by incubating rat hippocampal slices with the glutamate analogue D‐aspartate in the presence of PMB‐TBOA, which blocks the EAATs. After fixation of the slices, D‐aspartate taken up into the tissue was localized with the use of light microscopic immunoperoxidase and electron microscopic immunogold methods, exploiting highly specific antibodies against D‐aspartate. PMB‐TBOA blocked uptake of both low and high exogenous D‐aspartate concentrations (0.01–1.0 mM) into nerve terminals, as well as the uptake of 0.01 mM D‐aspartate into astrocytes. Interestingly, there was a residual PMB‐TBOA insensitive uptake of D‐aspartate in astrocytes at higher exogenous D‐aspartate concentrations (0.05–1.0 mM), strongly suggesting that astrocytes have “low‐affinity” uptake sites for excitatory amino acid. The PMB‐TBOA insensitive D‐aspartate uptake in astrocytes was sodium dependent and inhibited by succinate and to certain extent by homocysteate, but not by cystine or DIDS. We suggest that excitatory amino acid is transported into astrocytes in a “low‐affinity” fashion by sodium/dicarboxylate transporters. © 2008 Wiley‐Liss, Inc.
Vasoactive intestinal peptide protects against β‐amyloid‐induced neurodegeneration by inhibiting microglia activation at multiple levels
Authors: Delgado Mario , Varela Nieves , Gonzalez‐Rey Elena 
Published: April 2008

AbstractAlzheimer's disease (AD) is characterized by extracellular deposits of fibrillar β‐amyloid (Aβ) in the brain, increased microglial‐mediated inflammatory reactions in senile plaques, selective neuronal death, and cognitive deficits. The use of agents that limit microglial activation and inflammation in AD has recently emerged as an attractive therapeutic strategy for this disease. The vasoactive intestinal peptide (VIP), a widely distributed neuropeptide, has shown neuroprotective effects in acute brain damagein vivoand potent anti‐inflammatory actions in central nervous system. Here, we report that VIP inhibits Aβ‐induced neurodegeneration by indirectly inhibiting the production of a wide panel of inflammatory and neurotoxic agents by activated microglia cells. The inhibitory effect of VIP is mediated by blocking signaling through the p38 MAPK, p42/p44 MAPK, and NFkB cascades, the three major transduction pathways involved in the transcription of inflammatory mediators and the production of free radicals by Aβ‐activated microglia cells. Based on its neuroprotective action and its efficacy in inhibiting a broad range of inflammatory responses, VIP may provide a novel therapeutic approach to AD. © 2008 Wiley‐Liss, Inc.
Resting state sensorimotor functional connectivity in multiple sclerosis inversely correlates with transcallosal motor pathway transverse diffusivity
Authors: Lowe Mark J. , Beall Erik B. , Sakaie Ken E. , Koenig Katherine A. , Stone Lael , Marrie Ruth Ann , Phillips Micheal D. 
Published: April 2008

AbstractRecent studies indicate that functional connectivity using low‐frequency BOLD fluctuations (LFBFs) is reduced between the bilateral primary sensorimotor regions in multiple sclerosis. In addition, it has been shown that pathway‐dependent measures of the transverse diffusivity of water in white matter correlate with related clinical measures of functional deficit in multiple sclerosis. Taken together, these methods suggest that MRI methods can be used to probe both functional connectivity and anatomic connectivity in subjects with known white matter impairment. We report the results of a study comparing anatomic connectivity of the transcallosal motor pathway, as measured with diffusion tensor imaging (DTI) and functional connectivity of the bilateral primary sensorimotor cortices (SMC), as measured with LFBFs in the resting state. High angular resolution diffusion imaging was combined with functional MRI to define the transcallosal white matter pathway connecting the bilateral primary SMC. Maps were generated from the probabilistic tracking employed and these maps were used to calculate the mean pathway diffusion measures fractional anisotropy 〈FA〉, mean diffusivity 〈MD〉, longitudinal diffusivity 〈λ1〉, and transverse diffusivity 〈λ2〉. These were compared with LFBF‐based functional connectivity measures (Fc) obtained at rest in a cohort of 11 multiple sclerosis patients and ∼10 age‐ and gender‐matched control subjects. The correlation between 〈FA〉 and Fc for MS patients was r = −0.63, P < 0.04. The correlation between all subjects 〈λ2〉 and Fc was r = 0.42, P < 0.05. The correlation between all subjects 〈λ2〉 and Fc was r = −0.50, P < 0.02. None of the control subject correlations were significant, nor were 〈FA〉, 〈λ1〉, or 〈MD〉 significantly correlated with Fc for MS patients. This constitutes the first in vivo observation of a correlation between measures of anatomic connectivity and functional connectivity using spontaneous LFBFs. Hum Brain Mapp, 2008. © 2008 Wiley‐Liss, Inc.
Fusion core structure of the severe acute respiratory syndrome coronavirus (SARS‐CoV): In search of potent SARS‐CoV entry inhibitors
Authors: Chu Ling‐Hon Matthew , Chan Siu‐Hong , Tsai Sau‐Na , Wang Yi , Cheng Christopher Hon‐Ki , Wong Kam‐Bo , Waye Mary Miu‐Yee , Ngai Sai‐Ming 
Published: April 2008

AbstractSevere acute respiratory coronavirus (SARS‐CoV) spike (S) glycoprotein fusion core consists of a six‐helix bundle with the three C‐terminal heptad repeat (HR2) helices packed against a central coiled‐coil of the other three N‐terminal heptad repeat (HR1) helices. Each of the three peripheral HR2 helices shows prominent contacts with the hydrophobic surface of the central HR1 coiled‐coil. The concerted protein–protein interactions among the HR helices are responsible for the fusion event that leads to the release of the SARS‐CoV nucleocapsid into the target host‐cell. In this investigation, we applied recombinant protein and synthetic peptide‐based biophysical assays to characterize the biological activities of the HR helices. In a parallel experiment, we employed a HIV‐luc/SARS pseudotyped virus entry inhibition assay to screen for potent inhibitory activities on HR peptides derived from the SARS‐CoV S protein HR regions and a series of other small‐molecule drugs. Three HR peptides and five small‐molecule drugs were identified as potential inhibitors. ADS‐J1, which has been used to interfere with the fusogenesis of HIV‐1 onto CD4+ cells, demonstrated the highest HIV‐luc/SARS pseudotyped virus‐entry inhibition activity among the other small‐molecule drugs. Molecular modeling analysis suggested that ADS‐J1 may bind to the deep pocket of the hydrophobic groove on the surface of the central coiled‐coil of SARS‐CoV S HR protein and prevent the entrance of the SARS‐CoV into the host cells. J. Cell. Biochem. 104: 2335–2347, 2008. © 2008 Wiley‐Liss, Inc.
Photoionization cross sections with optimized orbital exponents within the complex basis function method
Authors: Morita Masato , Yabushita Satoshi 
Published: April 2008

AbstractWe show a new direction to expand the applicability of the complex basis function method for calculating photoionization cross sections through the imaginary part of the frequency‐dependent polarizability. Based on the variational stability of the frequency‐dependent polarizability, we made nonlinear optimizations of complex orbital exponents in basis functions representing continuum wave functions, and obtained fairly accurate results for H atom with only one or two complex basis functions particularly with dipole velocity gauge. Results were almost independent of whether Slater‐type or Gaussian‐type orbitals are used, implying the applicability to general many electron problems. The method was also applied to the 1S (1s)2 → 1P (1s)1(kp)1 cross section of He atom and the optimized complex orbital exponents were related to those of H atom through the scaling property. The nonlinear optimizations have converged smoothly and the cross sections were in excellent agreement with experiment throughout wide photon energies, which suggest the effectiveness of the approach for many‐electron systems. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008
Acute care hospital mortality of schizophrenic patients
Authors: Tokuda Yasuharu , Obara Haruo , Nakazato Nobuhiko , Stein Gerald H. 
Published: April 2008

AbstractBACKGROUND:Although schizophrenic patients have higher mortality than the general nonschizophrenic population, few studies have investigated acute care hospital mortality of schizophrenic patients.METHODS:To assess acute care hospital mortality of schizophrenic patients, we analyzed hospital mortality, the risk factors for hospital mortality, and the causes of death of schizophrenic patients admitted to an acute care hospital in Japan over an 18‐year period.RESULTS:We identified 55 deaths among 1108 schizophrenic patients, for a mortality rate of 5.0%. The overall standardized mortality ratio was 1.29 (95% CI, 0.98–1.68) compared with nonschizophrenic hospitalized patients. Significant risk factors for mortality were malignant neoplasm, cardiovascular disease, and admission through the emergency department. The leading causes of death in acute care hospitalizations were suicide (14.5%), malignant lymphoma or leukemia (10.9%), stroke (9.0%), and sepsis (7.3%).CONCLUSIONS:There was a nearly significant trend toward increased mortality of schizophrenic patients receiving acute hospital care compared with that of nonschizophrenic patients. Because suicide was the most frequent cause of death, a focus on suicide prevention is needed in this population. Journal of Hospital Medicine 2008;3:110–116. © 2008 Society of Hospital Medicine.
Innovative web‐based multimedia curriculum improves cardiac examination competency of residents
Authors: Criley Jasminka M. , Keiner Jennifer , Boker John R. , Criley Stuart R. , Warde Carole M. 
Published: April 2008

AbstractBACKGROUND:Proper diagnosis of cardiac disorders is a core competency of internists. Yet numerous studies have documented that the cardiac examination (CE) skills of physicians have declined compared with those of previous generations of physicians, attributed variously to inadequate exposure to cardiac patients and lack of skilled bedside teaching. With growing concerns about ensuring patient safety and quality of care, public and professional organizations are calling for a renewed emphasis on the teaching and evaluation of clinical skills in residency training.OBJECTIVE:The objective of the study was to determine whether Web training improves CE competency, whether residents retain what they learn, and whether a Web‐based curriculum plus clinical training is better than clinical training alone. Journal of Hospital Medicine 2008;3:124–133. © 2008 Society of Hospital Medicine.DESIGN:This was a controlled intervention study.PARTICIPANTS:The intervention group (34 internal and family medicine interns) participated in self‐directed use of a Web‐based tutorial and three 1‐hour teaching sessions taught by a hospitalist. Twenty‐five interns from the prior year served as controls.MEASUREMENTS:We assessed overall CE competency and 4 subcategories of CE competency: knowledge, audio skills, visual skills, and audio‐visual integration.RESULTS:The over mean score of the intervention group significantly improved, from 54 to 66 (P = .002). This improvement was retained (63.5, P = .05). When compared with end‐of‐year controls, the intervention group had significantly higher end‐of‐year CE scores (57 vs. 63.5, P = .05), knowledge (P = .04), and audio skills (P = .01). At the end of the academic year, all improvements were retained (P ≤ .04) except visual skills (P = .75).CONCLUSIONS:A Web‐based interactive educational program with minimal hospitalist involvement led to significant improvement in CE competence and was better than clinical training alone. © 2008 Society of Hospital Medicine.
A selective reaction of fructose bisphosphate aldolase with fluorescein isothiocyanate in chicken muscle extracts
Authors: Gehring Andrew G. , Ezzell John L. , Lebherz Herbert G. 
Published: April 2008

AbstractThe present work describes the selective covalent modification of fructose bisphosphate aldolase in crude extracts of chicken breast muscle by fluorescein 5′‐isothiocyanate (5′‐FITC) at pH 7.0 and 35°C. The modification was observed after 1 min while no other major soluble protein was labeled even after 30 min. We calculated that ca. one 5′‐FITC molecule was incorporated into each aldolase tetramer after a 30 min reaction which resulted in a minimal loss of enzyme activity. The “native” structure of aldolase was required for the selective modification by 5′‐FITC since high pH, high temperature, and ionic detergents either inhibited or prevented the reaction of 5′‐FITC with aldolase. Certain metabolites (ATP, ADP, CTP, GTP, FBP) and erythrosin B also inhibited the 5′‐FITC modification of aldolase. In contrast, F‐6‐P, AMP, NADH, and NAD+ as well as free lysine and most importantly, the 6′‐isomer of FITC exhibited no competition with 5′‐FITC for the labeling of aldolase. Alone, the 6′‐isomer of FITC did not exhibit preferential reaction when combined with aldolase. 5′‐FITC‐labeled and ‐unlabeled aldolases were not distinguished by their ability to bind to muscle myofibrils (MFs) or by their abilities to refold following reversible denaturation in urea. Structural analysis revealed that 5′‐FITC‐labeled a tryptic peptide corresponding to residues 112–134 in the primary structure of aldolase, a peptide that does not contain lysine, the amino acid believed to be the primary target of this reagent. Unlike chicken and rabbit muscle aldolases, chicken brain and liver aldolase isoforms along with several other aldolases derived from diverse biological sources did not exhibit this highly selective modification by 5′‐FITC. Copyright © 2008 John Wiley & Sons, Ltd.
Biomimetic affinity purification of cardiotoxin and its pharmacological effects on the nervous system
Authors: Dong Dexian , Liu Haoran , Xiao Qishi , Wang Ting , Liu Huaqing , Li Rongxiu 
Published: April 2008

AbstractCobra venom is a very precious natural resource. The traditional method for purification of cardiotoxin from cobra venom is a multi‐step, high cost, and low recovery procedure. By molecular modeling and docking with SYBYL software, we designed and synthesized an affinity ligand, m‐aminobenzoic acid, for high efficiency purification of this therapeutically useful Chinese cobra venom cardiotoxin. The one‐step recovery of cardiotoxin reached 64% and the purity reached 92% upon purification. The binding capacity of this synthetic ligand was 9.1 mg cardiotoxin/g moist weight gel and the affinity constant for cardiotoxin was 5.5 × 103 M−1. Unlike a natural affinity ligand, this synthetic ligand is highly stable, and has great potential for industrial scale production of cardiotoxin. In addition, we examined the effects of cardiotoxin on the nervous system in a mouse model. Results showed that cardiotoxin could maintain analgesic effects for 120 min with a dose of less than 0.06 mg/kg (2.8% of the LD50). Administration of 0.12 mg/kg cardiotoxin could improve scopolamine impairments of memory in mice. These results suggest that cardiotoxin may be a potential drug for nervous system diseases. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis and ITC characterization of novel nanoparticles constituted by poly(γ‐benzyl L‐glutamate)‐β‐cyclodextrin
Authors: Barbosa Ma. Elisa Martínez , Bouteiller Laurent , Cammas‐Marion Sandrine , Montembault Véronique , Fontaine Laurent , Ponchel Gilles 
Published: April 2008

AbstractImparting desired technological characteristics to polymeric nanoparticles requires the development of original polymers. In the present work, the synthesis and characterization of a novel PBLG‐derivative, the poly(γ‐benzyl L‐glutamate)‐β‐cyclodextrin (PBLG‐β‐CD‐50), have been carried out. Nanoparticles from either PBLG‐β‐CD‐50 polymer or from mixtures with PBLG have been prepared using a modified nanoprecipitation method. Spherically shaped nanoparticles with diameter in the range of 50–70 nm were obtained, as determined by dynamic laser light scattering and transmission electron microscopy. The presence of a surfactant in the suspension medium had almost no influence on these parameters and was not necessary to the shelf‐stability of the suspension. Further, isothermal titration microcalorimetry (ITC) experiments have been used to show unambiguously that about 20% of the cyclodextrins remain functional within the particles. Consequently, this system may be of interest when association of large amounts of hydrophobic drugs to nanoparticles is required. Copyright © 2008 John Wiley & Sons, Ltd.
Activation of the extracellular signal‐regulated kinases 1 and 2 by glial cell line‐derived neurotrophic factor and its relation to neuroprotection in a mouse model of Parkinson's disease
Authors: Lindgren Niklas , Leak Rehana K. , Carlson Kirsten M. , Smith Amanda D. , Zigmond Michael J. 
Published: April 2008

AbstractGlial cell line‐derived neurotrophic factor (GDNF) has been shown to be neuroprotective in animal models of the dopamine deficiency in Parkinson's disease. To examine the role of the extracellular signal‐regulated kinases 1 and 2 (ERK1/2) in this process, we infused a single dose of GDNF into the striatum of mice and analyzed the effect on ERK1/2 by immunohistochemistry and Western blot analysis. GDNF caused an increase in the phosphorylation of ERK1/2 both in the striatum and in tyrosine hydroxylase‐positive neurons in the substantia nigra. In the striatum, the increase in ERK1/2 phosphorylation was evident by 3 hr and persisted for at least 7 days, whereas, in the substantia nigra, an increase in phosphorylated ERK1/2 was first evident at 24 hr and persisted for at least 7 days. The increase in phosphorylated ERK1/2 was maximal at 0.45 μg GDNF at the time points examined. GDNF also protected dopamine terminals against the loss of tyrosine hydroxylase immunoreactivity normally associated with the intrastriatal administration of 6‐hydroxydopamine (0.5 μg/0.5 μl). However, this was observed only at a much higher dose of GDNF, 4.5 μg. Thus, our results suggest that the ability of GDNF to protect dopamine neurons cannot be explained solely in terms of its influence on ERK1/2 and that the role of other signaling pathways should be explored. © 2008 Wiley‐Liss, Inc.
Variability in sea‐surface temperature and winds in the tropical south‐east Atlantic Ocean and regional rainfall relationships
Authors: Hermes J. C. , Reason C. J. C. 
Published: April 2008

AbstractVariability in sea‐surface temperature (SST) and winds in the Angola Benguela frontal zone (ABFZ) in the tropical south‐east Atlantic Ocean has previously been shown to be important for regional fisheries and for seasonal rainfall anomalies over Angola/Namibia in austral summer and coastal West Africa in boreal summer. This study investigates intraseasonal variability in winds and SST over this region using QuikSCAT and tropical rainfall measuring mission (TRMM) satellite data for 1999–2004. Wavelet analyses reveal periods of relatively strong power in the 20–30 or 30–64 day frequency bands throughout the record but that there is substantial interannual variability in the occurrence of these intraseasonal oscillations. The implications of this variability for seasonal rainfall anomalies during the main rainy seasons in southern Africa (austral summer) and coastal West Africa (boreal summer) are discussed. Copyright © 2008 Royal Meteorological Society
Raman spectroscopy of ionic liquids derived from 1‐n‐butyl‐3‐methylimidazolium chloride and niobium chloride or zinc chloride mixtures
Authors: Alves Melquizedeque B. , Santos jr. Vianney O. , Soares Valerio C. D. , Suarez Paulo A. Z. , Rubim Joel C. 
Published: April 2008

AbstractAnionic species formed in mixtures of 1‐n‐butyl‐3‐methylimidazolium chloride (BMICl) with different amounts of niobium pentachloride (NbCl5) or zinc dichloride (ZnCl2) were investigated by Raman spectroscopy. In the BMICl and NbCl5 ionic mixtures the presence of the anion NbCl6− was detected for all compositions (molar fraction, X) and a mixture of this anion and the neutral Nb2Cl10 in acid ones. Two different anions were observed for basic mixtures of BMICl and ZnCl2: ZnCl42−(0 < X < 0.35) and Zn2Cl62−(X > 0.3), whereas for acidic ones three species were detected: Zn2Cl62−(X < 0.7), Zn3Cl82−(X > 0.7) and Zn4Cl102−(X > 0.7). It has also been observed that in both cases, the formation of larger anions causes a shift of the CH stretching modes to higher wavenumbers as the result of a decrease in the hydrogen bond between Cl and the hydrogens from the cation. Copyright © 2008 John Wiley & Sons, Ltd.
Chromatographic deuterium isotope effects of derivatized N‐glycans and N‐glycopeptides in a zwitterionic type of hydrophilic interaction chromatography
Authors: Takegawa Yasuhiro , Hato Megumi , Deguchi Kisaburo , Nakagawa Hiroaki , Nishimura Shin‐Ichiro 
Published: April 2008

AbstractHPLC/MS is now an essential method for the analysis of glycans and glycopeptides. A technique using ICATs is also becoming popular for their comparative/quantitative analysis based on MS signal intensities. However, the RP HPLC most often used causes “doublet” peaks of deuterium‐labeled and nonlabeled peptides, which are well known for causing the chromatographic deuterium isotope effect. Such doublet peaks are undesirable for precise comparison of MS signal intensities. This report shows that, in the zwitterionic type of hydrophilic interaction chromatography, the chromatographic deuterium isotope effect is negligibly small for N‐glycans derivatized with deuterium‐labeled 2‐aminopyridine and N‐glycopeptides derivatized with deuterium‐labeled succinic anhydride.