bluuebunny/crossref_metadata_2025_split huggingface dataset:
Highly crosslinked poly(styrene‐co‐divinylbenzene) microspheres prepared by precipitation polymerization: Effects of the polymerization parameters on the characteristics of the particles
Authors: Cui Hengli , Chen Hou , Qu Rongjun , Wang Chunhua , Sun Changmei , Zhou Wenying , Yu Mengmeng , Jiang Hongyan 
Published: December 2008

AbstractHighly crosslinked poly(styrene‐co‐divinylbenzene) microspheres with a 1.0–2.5‐μm diameter were prepared by precipitation polymerization in neat acetonitrile. The effects of various polymerization parameters such as the monomer and initiator concentration, comonomer composition, and cosolvents on the properties of the resulting particles were studied. The particle diameter increased with the monomer concentration, whereas the particle size distribution remained almost constant. The resulting yield of the particles reached 41.1% when 6 wt % 2,2′‐azobisisobutyronitrile (based on the total monomer) was used as the initiator. The styrene fraction in the monomer composition and toluene fraction in the solvent mixture also significantly affected the morphology and size of the resulting particles. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Aqueous deposited copolymerization of acrylonitrile and itaconic acid
Authors: Zhao Yaqi , Wang Chengguo , Wang Yanxiang , Zhu Bo 
Published: December 2008

AbstractAqueous deposited copolymerization reactions of acrylonitrile (AN) with itaconic acid (IA) were carried out in deionized water at 60°C with a single water‐soluble initiator. High‐molecular‐weight polyacrylonitrile (PAN) copolymers were acquired by adjustment of technical polymerization parameters. When the amount of IA in the feed reached 2 wt %, the conversion of the polymerization reaction, intrinsic viscosity, and viscosity‐average molecular weight all achieved their maximum values, whereas the molecular weight distribution achieved its minimum value. The AN/IA reactivity ratios, calculated with Q–e schemes (where Q and e are measures of the reactivity and polarity, respectively), agreed well with those determined with the Fineman–Ross and Kelen–Tüdõs methods. The thermal properties and structural characteristics of the PAN polymers were measured with differential scanning calorimetry and Fourier transform infrared spectroscopy. The introduction of IA into the polymerization system was found to be propitious for the preoxidation of the PAN polymers, and the characteristic absorption bands of CN, CO, or OH existed in the polymer main chains. With an increase in the required amount of IA in the polymerization system, the exothermic figure of the exotherms became broader, and the intensity of the CO and OH absorption bands became stronger. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Developmental course of EphA4 cellular and subcellular localization in the postnatal rat hippocampus
Authors: Tremblay Marie‐Ève , Riad Mustapha , Chierzi Sabrina , Murai Keith K. , Pasquale Elena B. , Doucet Guy 
Published: December 2008

AbstractFrom embryonic development to adulthood, the EphA4 receptor and several of its ephrin‐A or ‐B ligands are expressed in the hippocampus, where they presumably play distinct roles at different developmental stages. To help clarify these diverse roles in the assembly and function of the hippocampus, we examined the cellular and subcellular localization of EphA4 in postnatal rat hippocampus by light and electron microscopic immunocytochemistry. On postnatal day (P) 1, the EphA4 immunostaining was robust in most layers of CA1, CA3, and dentate gyrus and then decreased gradually, until P21, especially in the cell body layers. At the ultrastructural level, focal spots of EphA4 immunoreactivity were detected all over the plasma membrane of pyramidal and granule cells, between P1 and P14, from the perikarya to the dendritic and axonal extremities, including growth cones and filopodia. This cell surface immunoreactivity then became restricted to the synapse‐associated dendritic spines and axon terminals by P21. In astrocytes, the EphA4 immunolabeling showed a similar cell surface redistribution, from the perikarya and large processes at P1–P7, to small perisynaptic processes at P14–P21. In both cell types, spots of EphA4 immunoreactivity were also detected, with an incidence decreasing with maturation, on the endoplasmic reticulum, Golgi apparatus, and vesicles, organelles involved in protein synthesis, posttranslational modifications, and transport. The cell surface evolution of EphA4 localization in neuronal and glial cells is consistent with successive involvements in the developmental movements of cell bodies first, followed by process outgrowth and guidance, synaptogenesis, and finally synaptic maintenance and plasticity. J. Comp. Neurol. 512:798–813, 2009. © 2008 Wiley‐Liss, Inc.
Character impact odorants from Brassicaceae by aroma extract dilution analysis (AEDA): Brassica cretica and Brassica insularis
Authors: Breme Katharina , Langle Stéphane , Fernandez Xavier , Meierhenrich Uwe J. , Brevard Hugues , Joulain Daniel 
Published: December 2008

AbstractVolatile extracts of two wild cabbages, Brassica cretica and Brassica insularis, were studied by GC–MS, GC/FID, and GC–olfactometry/aroma extract dilution analysis (GC–O/AEDA). Major compounds were 3‐butenyl cyanide (70% of the total GC/FID area) and 3‐butenyl isothiocyanate (29%) in B. cretica and 2‐phenylethyl cyanide (53%) and 2‐phenylethyl isothiocyanate (21%) in B. insularis. AEDA revealed the impact of five heteroatomic trace compounds (diacetyl, methional, furfuryl thiol, 1‐octen‐3‐one and skatole) with moderate to high flavour dilution (FD) factors that were detected only due to GC–O analyses. Copyright © 2008 John Wiley & Sons, Ltd.
Aggression is related to frontal serotonin‐1A receptor distribution as revealed by PET in healthy subjects
Authors: Witte A. Veronica , Flöel Agnes , Stein Patrycja , Savli Markus , Mien Leonhard‐Key , Wadsak Wolfgang , Spindelegger Christoph , Moser Ulrike , Fink Martin , Hahn Andreas , Mitterhauser Markus , Kletter Kurt , Kasper Siegfried , Lanzenberger Rupert 
Published: December 2008

AbstractObjectives: Various studies indicate that serotonin regulates impulsivity and the inhibitory control of aggression. Aggression is also known to be modified by sex hormones, which exert influence on serotonergic neurotransmission. The present study aimed to elucidate potential interactions between human aggression, the inhibitory serotonergic 5‐HT1Areceptor, and sex hormones.Experimental Design: Thirty‐three healthy volunteers (16 women, aged 26.24 ± 5.5 yr) completed a validated questionnaire incorporating five dimensions of aggression. Subsequently, all subjects underwent positron emission tomography with the radioligand [carbonyl‐11C]WAY‐100635 to quantify 5‐HT1Abinding potentials (BPNDs) in the prefrontal cortex, limbic areas, and midbrain. Also, plasma levels of testosterone, 17ß‐estradiol and sex hormone‐binding globulin (SHBG) were measured. Relations between aggression scores, regional 5‐HT1ABPNDs, and hormone levels were analyzed using correlations, multivariate analyses of variance, and linear regressions.Principal Observations: Statistical analyses revealed higher 5‐HT1Areceptor BPNDs in subjects exhibiting higher aggression scores in prefrontal (allP< 0.041) and anterior cingulate cortices (P= 0.016). More aggressive subjects were also characterized by lower SHBG levels (P= 0.015). Moreover, higher SHBG levels were associated with lower 5‐HT1ABPNDs in frontal (P= 0.048) and cingulate cortices (allP< 0.013) and in the amygdala (P= 0.03).Conclusions:The present study provides first‐time evidence for a specific interrelation between the 5‐HT1Areceptor distribution, sex hormones, and aggression in humans. Our findings point to a reduced down‐stream control due to higher amounts or activities of frontal 5‐HT1Areceptors in more aggressive subjects, which is presumably modulated by sex hormones. Hum Brain Mapp 30:2558–2570, 2009. © 2008 Wiley‐Liss, Inc.
Epstein‐Barr virus and the pathogenesis of Burkitt's lymphoma: More questions than answers
Authors: Bornkamm Georg W. 
Published: December 2008

AbstractBurkitt's lymphoma (BL) was first described as a clinical entity in children in Central Africa by Denis Burkitt in 1958. The particular epidemiological features of this tumor initiated the search for a virus as the causative agent and led to the discovery of Epstein‐Barr virus (EBV) by Epstein and coworkers in 1964. It became apparent in the seventies and eighties that the tumor is not restricted to Central Africa, but occurs with lesser incidence all over the world (sporadic BL) and is also particularly frequent in HIV infected individuals, and that not all BL cases are associated with EBV: about 95% of the cases in Central Africa, 40 to 50% of the cases in HIV‐infected individuals and 10 to 20% of the sporadic cases harbour the viral information and express at least one viral antigen (EBNA1) and a number of non‐coding viral RNAs. In contrast, all BL cases regardless of their geographical origin exhibit one of three c‐myc/Ig chromosomal translocations leading to the activation of the c‐myc gene as a crucial event in the development of this disease. Although epidemiological evidence clearly points to a role of the virus in the African cases, the role of EBV in the pathogenesis of BL has remained largely elusive. This review summarizes current concepts and ideas how EBV might contribute to the development of BL in the light of the progress made in the last decade and discusses the problems of the experimental systems available to test such hypotheses. © 2008 Wiley‐Liss, Inc.
Computational chemistry study of 3D‐structure‐function relationships for enzymes based on Markov models for protein electrostatic, HINT, and van der Waals potentials
Authors: Concu Riccardo , Podda Gianni , Uriarte Eugenio , González‐Díaz Humberto 
Published: December 2008

AbstractIn a significant work, Dobson and Doig (J Mol Biol 2003, 330, 771) illustrated protein prediction as enzymatic or not from spatial structure without resorting to alignments. They used 52 protein features and a nonlinear support vector machine model to classify more than 1000 proteins collected from the PDB with a 77% overall accuracy. The most useful features were: the secondary‐structure content, the amino acid frequencies, the number of disulphide bonds, and the largest cleft size. Working on the same dataset used by D&D, in this article we reported a good and simple model, based on the Markov chain models (MCM), to classify protein 3D structures as enzymatic or not, taking into consideration the spatial structure without resorting to alignments. Here we define, for the first time, a general MCM to calculate the electrostatic potential, molecular vibrations, van der Waals (vdw) interactions, and hydrophobic interactions (HINT) and use them in comparative studies of potential fields and/or protein function prediction. The dataset is composed of 1371 proteins divided into 689 enzymes and 682 nonenzymes, all proteins were collected from the PDB. The best model we found was a linear model carried out with the linear discriminant analysis; it was able to classify 74.18% of the proteins using only two electrostatic potentials. In the work described here, we define 3D‐HINT potentials (μk) and use them for the first time to derive a classifier for protein enzymes. We analyzed ROC curves, domain of applicability, parametric assumptions, desirability maps, and also tested other nonlinear artificial neural network models which did not improve the linear model. In closing, this MCM allows a fast calculation and comparison of different potentials deriving into accurate protein 3D structure‐function relationships, notably simpler than the previous. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009
Efficiency and productivity growth in hotel industry
Authors: Barros Carlos Pestana , Peypoch Nicolas , Solonandrasana Bernardin 
Published: December 2008

AbstractThis paper analyses the relative efficiency and productivity of a representative sample of Portuguese hotels by using the directional distance function and the Luenberger productivity indicator. The key advantage of this approach is that both input contraction and output expansion are considered. The model generates hotel efficiency scores, ranking the hotels in the sample. We conclude that both inputs and outputs play a major role in hotel efficiency. Therefore, we suggest an alteration of management procedures in order to enable efficiency to be increased, based on an effective enhanced‐incentive policy and taking into account the small hotel characteristics of the sample. Copyright © 2008 John Wiley & Sons, Ltd.
Sex differences in time to task failure and blood flow for an intermittent isometric fatiguing contraction
Authors: Hunter Sandra K. , Griffith Erin E. , Schlachter Kristine M. , Kufahl Tim D. 
Published: December 2008

AbstractThe purpose of this study was to compare the time to task failure, postcontraction hyperemia, and vascular conductance of young men and women for a submaximal intermittent fatiguing contraction performed with the handgrip muscles. Twenty men and 20 women (mean ± SD: 22 ± 4 years) performed an isometric contraction at 50% of maximal voluntary contraction (MVC) (6‐s contraction, 4‐s rest) until task failure. Forearm venous occlusion plethysmography was used to estimate the peak blood flow (after 10‐min occlusion) and blood flow at rest after 6‐s submaximal contractions of varying intensities, and during an intermittent fatiguing contraction at 1‐min intervals and task failure. The time to task failure was longer for the women compared with the men (408 ± 205 s vs. 297 ± 57 s, P < 0.05). Postcontraction hyperemia and vascular conductance were greater for men than for women after nonfatiguing 6‐s submaximal contractions performed at 20%, 40%, 50%, 60%, and 80% of MVC force (P < 0.05). In contrast, hyperemia and vascular conductance were similar for both genders when measured at 50 s into the fatiguing contraction, at each minute thereafter, and at task failure. Regression analysis indicated that the rate of electromyographic activity and perceived exertion were the significant predictors of the time to task failure. The longer time to task failure for women compared with men for an intermittent fatiguing contraction with handgrip muscles was not explained by postcontraction hyperemia or vascular conductance with fatigue. © 2008 Wiley Periodicals, Inc. Muscle Nerve 39: 42–53, 2009
Evaluation of distal symmetric polyneuropathy: The role of autonomic testing, nerve biopsy, and skin biopsy (an evidence‐based review)
Authors: England J.D. , Gronseth G.S. , Franklin G. , Carter G.T. , Kinsella L.J. , Cohen J.A. , Asbury A.K. , Szigeti K. , Lupski J.R. , Latov N. , Lewis R.A. , Low P.A. , Fisher M.A. , Herrmann D. , Howard J.F. , Lauria G. , Miller R.G. , Polydefkis M. , Sumner A.J. ,   American Academy of Neurology,   American Association of Neuromuscular and Electrodiagnostic Medicine,   American Academy of Physical Medicine and Rehabilitation
Published: December 2008

AbstractDistal symmetric polyneuropathy (DSP) is the most common variety of neuropathy. Since the evaluation of this disorder is not standardized, the available literature was reviewed to provide evidence‐based guidelines regarding the role of autonomic testing, nerve biopsy, and skin biopsy for the assessment of polyneuropathy. A literature review using MEDLINE, EMBASE, Science Citation Index, and Current Contents was performed to identify the best evidence regarding the evaluation of polyneuropathy published between 1980 and March 2007. Articles were classified according to a four‐tiered level of evidence scheme and recommendations were based on the level of evidence. (1) Autonomic testing may be considered in the evaluation of patients with polyneuropathy to document autonomic nervous system dysfunction (Level B). Such testing should be considered especially for the evaluation of suspected autonomic neuropathy (Level B) and distal small fiber sensory polyneuropathy (SFSN) (Level C). A battery of validated tests is recommended to achieve the highest diagnostic accuracy (Level B). (2) Nerve biopsy is generally accepted as useful in the evaluation of certain neuropathies as in patients with suspected amyloid neuropathy, mononeuropathy multiplex due to vasculitis, or with atypical forms of chronic inflammatory demyelinating polyneuropathy (CIDP). However, the literature is insufficient to provide a recommendation regarding when a nerve biopsy may be useful in the evaluation of DSP (Level U). (3) Skin biopsy is a validated technique for determining intraepidermal nerve fiber (IENF) density and may be considered for the diagnosis of DSP, particularly SFSN (Level C). There is a need for additional prospective studies to define more exact guidelines for the evaluation of polyneuropathy. Muscle Nerve 39: 106–115, 2009
An ADI Petrov–Galerkin method with quadrature for parabolic problems
Authors: Bialecki B. , Ganesh M. , Mustapha K. 
Published: December 2008

AbstractWe propose and analyze a fully discrete Laplace modified alternating direction implicit quadrature Petrov–Galerkin (ADI‐QPG) method for solving parabolic initial‐boundary value problems on rectangular domains. We prove optimal order convergence results for a restricted class of the associated elliptic operator and demonstrate accuracy of our scheme with numerical experiments for some parabolic problems with variable coefficients.© 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
An efficient TVD‐WENO method for conservation laws
Authors: Zahran Yousef Hashem 
Published: December 2008

AbstractIn this article, we present a high‐resolution hybrid scheme for solving hyperbolic conservation laws in one and two dimensions. In this scheme, we use a cheap fourth order total variation diminishing (TVD) scheme for smooth region and expensive seventh order weighted nonoscillatory (WENO) scheme near discontinuities. To distinguish between the smooth parts and discontinuities, we use an efficient adaptive multiresolution technique. For time integration, we use the third order TVD Runge‐Kutta scheme. The accuracy of the resulting hybrid high order scheme is comparable with these of WENO, but with significant decrease of the CPU cost. Numerical demonstrates that the proposed scheme is comparable to the high order WENO scheme and superior to the fourth order TVD scheme. Our scheme has the added advantage of simplicity and computational efficiency. Numerical tests are presented which show the robustness and effectiveness of the proposed scheme.© 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
A secular equation for the Jacobian matrix of certain multispecies kinematic flow models
Authors: Donat Rosa , Mulet Pep 
Published: December 2008

AbstractMultispecies kinematic flow models lead to nonlinear systems of conservation laws with a possibly large number of unknowns, the concentrations or the densities of the different species. In recent years, the hyperbolic character of several of these models has been analyzed by considering the characteristic polynomial of the Jacobian matrix of the system. This analysis can be considerably simplified by realizing that the fluxes in these models have a particular algebraic structure that can be exploited within a systematic algebraic framework. The framework can serve to determine the eigenvalues, and even the eigenvectors, of the Jacobian matrix of the system, which allows the use of characteristic‐based high‐resolution shock capturing schemes in numerical simulations.© 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010
Influence of alkoxy tail length and unbalanced mesogenic core on phase behavior of mesogen‐jacketed liquid crystalline polymers
Authors: Chen Si , Zhang Lan‐Ying , Gao Long‐Cheng , Chen Xiao‐Fang , Fan Xing‐He , Shen Zhihao , Zhou Qi‐Feng 
Published: December 2008

AbstractWhen the flexible terminal substituent changes from butoxy to hexyloxy or longer, smectic C (SC) liquid crystalline phase was firstly reported to develop from a kind of mesogen‐jacketed liquid crystalline polymer (MJLCP) whose mesogenic side groups are unbalancedly bonded to the main chain without spacers. A series of MJLCPs, poly[4,4′‐bis(4‐alkoxyphenyl)‐2‐vinylbiphenyl(carboxide)] (nC2Vp, n is the number of the carbons in the alkoxy groups, n = 2, 4, 6, 8, 10, and 12) were designed and synthesized successfully via free radical polymerization. The molecular weights of the polymers were characterized with gel permeation chromatography, and the liquid crystalline properties were investigated by differential scanning calorimetry, polarized light microscopy experiments, and 1D, 2D wide‐angle X‐ray diffraction. Comparing with the butoxy analog, the polymer with unbalanced mesogenic core and shorter flexible substituents (n = 2, 4) keeps the same smectic A (SA) phase, but other polymers with longer terminal flexible substituents (n = 6, 8, 10, and 12) can develop into a well‐defined SC phase instead of SA phase. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 505–514, 2009
Dendrimers in thiol‐ene crosslinked networks and the effect of subsequent generations on thermoset properties
Authors: Nilsson Camilla , Malmström Eva , Johansson Mats , Trey Stacy M. 
Published: December 2008

AbstractA series of well‐defined allyl‐ether functionalized polyester dendrimers has been synthesized via the divergent approach using traditional esterification reactions. Two commercially available trifunctional thiols, trimethylolpropane tri(3‐mercaptopropanoate) (TRIS) and ethoxylated trimethylolpropane tri(3‐mercaptopropanoate) (ETTMP), were incorporated with the dendrimers into the thiol‐ene polymer networks. The thiol‐ene reactions were conducted at room temperature and cured by UV light without the addition of photoinitiatior. Highly crosslinked films were obtained and characterized with respect to mechanical (DMA) and thermal (DSC and TGA) properties. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 589–601, 2009
An unusually small dimer interface is observed in all available crystal structures of cytosolic sulfotransferases
Authors: Weitzner Brian , Meehan Thomas , Xu Qifang , Dunbrack Roland L. 
Published: December 2008

AbstractCytosolic sulfotransferases catalyze the sulfonation of hormones, metabolites, and xenobiotics. Many of these proteins have been shown to form homodimers and heterodimers. An unusually small dimer interface was previously identified by Petrotchenko et al. (FEBS Lett 2001;490:39–43) by cross‐linking, protease digestion, and mass spectrometry and verified by site‐directed mutagenesis. Analysis of the crystal packing interfaces in all 28 available crystal structures consisting of 17 crystal forms shows that this interface occurs in all of them. With a small number of exceptions, the publicly available databases of biological assemblies contain either monomers or incorrect dimers. Even crystal structures of mouse SULT1E1, which is a monomer in solution, contain the common dimeric interface, although distorted and missing two important salt bridges. Proteins 2009. © 2008 Wiley‐Liss, Inc.