bluuebunny/crossref_metadata_2025_split huggingface dataset:
α‐Tocopheryl phosphate – An active lipid mediator?
Authors: Zingg Jean‐Marc , Meydani Mohsen , Azzi Angelo 
Published: February 2010

AbstractThe vitamin E (α‐tocopherol, αT) derivative, α‐tocopheryl phosphate (αTP), is detectable in small amounts in plasma, tissues, and cultured cells. Studies done in vitro and in vivo suggest that αT can become phosphorylated and αTP dephosphorylated, suggesting the existence of enzyme(s) with αT kinase or αTP phosphatase activity, respectively. As a supplement in animal studies, αTP can reach plasma concentrations similar to αT and only a part is dephosphorylated; thus, αTP may act both as pro‐vitamin E, but also as phosphorylated form of vitamin E with possibly novel regulatory activities. Many effects of αTP have been described: in the test tube αTP modulates the activity of several enzymes; in cell culture αTP affects proliferation, apoptosis, signal transduction, and gene expression; in animal studies αTP prevents atherosclerosis, ischemia/reperfusion injury, and induces hippocampal long‐term potentiation. At the molecular level, αTP may act as a cofactor for enzymes, as an active lipid mediator similar to other phosphorylated lipids, or indirectly by altering membrane characteristics such as lipid rafts, fluidity, and curvature. In this review, the molecular and cellular activities of αTP are examined and the possible functions of αTP as a natural compound, cofactor and active lipid mediator involved in signal transduction and gene expression discussed.
Tautomerism and isotopic multiplets in the 13C NMR spectra of partially deuterated 3‐arylpyrimido[4,5‐c]pyridazine‐5,7(6H,8H)‐diones and their sulfur analogs—evidence for elucidation of the structure backbone and tautomeric forms
Authors: Rimaz Mehdi , Noroozi Pesyan Nader , Khalafy Jabbar 
Published: February 2010

AbstractThe tautomerism of the synthesized 3‐arylpyrimido[4,5‐c]pyridazine‐5,7(6H,8H)‐diones (1a–d) and 3‐aryl‐7‐thioxo‐7,8‐dihydro‐6H‐pyrimido[4,5‐c]pyridazine‐5‐ones (2a–d) was studied in dimethyl sulfoxide (DMSO)‐d6. 1H NMR spectra of 1a–d showed a clustered water molecule in the structure backbone that is attached by strong intermolecular H bonding. The relation between the temperature and H bonding of the clustered water molecule with 1a was also studied as representative. The relation between the electronegativity (χ) of the substituent on phenyl ring and the chemical shifts of clustered water protons in 1a–d was also studied. All of 1a–d and also 2d compounds existed in lactam (I) form, whereas 2a–c compounds have two distinguished tautomers in DMSO‐d6 [lactam (I) and lactim (II) forms]. The solvent‐substrate proton exchange was examined in compounds 1a–d and 2a–d by adding one drop of D2O. All compounds (except 1d) showed proton/deuterium exchange of the clustered water protons in DMSO by adding one drop of D2O. Some compounds (but not all of them) that are easily soluble in DMSO‐d6 containing D2O showed isotopic splitting (β‐isotope effect) in their 13C NMR spectra. Among them, compound 1a was the best evidence to help the spectral assignments and structure determination of predominant tautomer by carbon‐13 splitting (β‐isotope effect). Copyright © 2010 John Wiley & Sons, Ltd.
Validation of an incremental motor unit number estimation technique in rabbits
Authors: David William S. , Goyal Namita , Henry Francis P. , Baldassari Laura E. , Redmond Robert W. 
Published: February 2010

AbstractMotor unit number estimation (MUNE) allows for quantitative assessment of functional motor units in a nerve. Several techniques have been applied to human studies. Although MUNE has been performed in animals to study neurological disorders, reproducibility has not been addressed. We analyzed the test–retest reproducibility of an incremental MUNE technique in rabbits and performed histological correlation. A peroneal MUNE was performed in 9 rabbits on two occasions separated by 30 days. MUNE was then performed on 18 rabbits prior to euthanize. A count of total fibers and a second count of large myelinated fibers were performed on nerve cross‐sections. Test–retest reproducibility revealed an intraclass correlation coefficient (ICC) of 0.75. The average test–retest relative difference was 26.6%. Comparison of MUNE and histomorphometrical counts revealed a correlation coefficient (r) of 0.21 (total fiber counts) and 0.27 (large fibers). Although incremental MUNE has a high degree of reproducibility in rabbits, there is poor correlation with histological fiber counts. Muscle Nerve, 2010
Effects of prolonged repetitive stimulation of median, ulnar and peroneal nerves
Authors: Baumann Fusun , Henderson Robert D. , Tremayne Fred , Hutchinson Nicole , McCombe Pamela A. 
Published: February 2010

AbstractIt is important to know the effects of prolonged repetitive nerve stimulation (RNS) when it is used in neurophysiological studies. RNS with up to 100 supramaximal stimuli was given to the median, ulnar, and peroneal nerves of normal subjects and the ulnar nerves of subjects with early amyotrophic lateral sclerosis (ALS), recording evoked compound muscle action potentials (CMAPs). In all nerves, there was a decline in the CMAP area and a decrease in CMAP duration. For the peroneal nerve there was a decline in the CMAP amplitude, but a similar decline was not seen in the median or ulnar nerves. Cooling of the muscles resulted in decrement of both the amplitude and area with RNS. In ALS subjects, CMAP amplitude and area both declined after RNS of the ulnar nerve. In this study we describe the changes in CMAP with prolonged RNS among commonly tested normal nerves. Our findings have important implications with regard to RNS. Muscle Nerve, 2010
Branched‐chain amino acids protect against dexamethasone‐induced soleus muscle atrophy in rats
Authors: Yamamoto Daisuke , Maki Taiki , Herningtyas Elizabeth Henny , Ikeshita Nobuko , Shibahara Hiromi , Sugiyama Yuka , Nakanishi Shiho , Iida Keiji , Iguchi Genzo , Takahashi Yutaka , Kaji Hidesuke , Chihara Kazuo , Okimura Yasuhiko 
Published: February 2010

AbstractWe investigated the utility of branched‐chain amino acids (BCAA) in dexamethasone‐induced muscle atrophy. Dexamethasone (600 μg/kg, intraperitoneally) and/or BCAA (600 mg/kg, orally) were administered for 5 days in rats, and the effect of BCAA on dexamethasone‐induced muscle atrophy was evaluated. Dexamethasone decreased total protein concentration of rat soleus muscles. Concomitant administration of BCAA reversed the decrease. Dexamethasone decreased mean cross‐sectional area of soleus muscle fibers, which was reversed by BCAA. Dexamethasone increased atrogin‐1 expression, which has been reported to play a pivotal role in muscle atrophy. The increased expression of atrogin‐1 mRNA was significantly attenuated by BCAA. Furthermore, dexamethasone‐induced conversion from microtubule‐associated protein 1 light chain 3 (LC3)‐I to LC3‐II, which is an indicator of autophagy, was blocked by BCAA. These findings suggest that BCAA decreased protein breakdown to prevent muscle atrophy. BCAA administration appears to be useful for prevention of steroid myopathy. Muscle Nerve, 2010
Sinusoidal oscillations radiating from a cylindrical source in thermal conduction or groundwater flow: Closed‐form solutions
Authors: Saucier Antoine , Frappier Clément , Chapuis Robert P. 
Published: February 2010

AbstractThe diffusion equation governs thermal conduction and groundwater flow phenomena. In this paper, we study the two‐dimensional radial propagation of a sinusoidal perturbation radiating from a cylindrical source within an infinite slab of homogeneous material. The solution of this problem has several applications. For instance, it can be used to determine the hydraulic diffusivity of the subsurface based on measurements of the hydraulic head around a vertical well during its development. For thermal problems, it can be used to determine the thermal diffusivity based on measurements of the temperature distribution around a cylindrical heat source generating a sinusoidal power per unit length. In this paper, we present a comprehensive analytical solution of this problem and we compare these solutions with numerical solutions. Two approximate analytical solutions, which can be relevant in practice, are also presented. Finally, we give an upper bound for the survival time of the transient part of the solution and we provide an estimate of the radius of influence of the sinusoidal solicitation. Copyright © 2010 John Wiley & Sons, Ltd.
Time‐scale analysis in unsaturated porous media under external wave loads
Authors: Xiao Heng , Young Yin Lu , Prévost Jean H. 
Published: February 2010

AbstractExtreme waves caused by tsunamis and storm surges can lead to soil failures in the near‐shore region, which may have severe impact on coastal environments and communities. Multiphase flows in deformable porous media involve several coupled processes and multiple time scales, which are challenging for numerical simulations. The objective of this study is to investigate the roles of the various processes and their interactions in multiphase flows in unsaturated soils under external wave loading, via theoretical time‐scale analysis and numerical simulations. A coupled geomechanics–multiphase flow model based on conservation laws is used. Theoretical analysis based on coupled and decoupled models demonstrates that transient and steady‐state responses are governed by pore pressure diffusion and saturation front propagation, respectively, and that the two processes are essentially decoupled. Numerical simulations suggest that the compressibility of the pore fluids and the deformation of the soil skeleton are important when the transient responses of the media are of concern, while the steady‐state responses are not sensitive to these factors. The responses obtained from the fully coupled numerical simulations are explained by a simplified time‐scale analysis based on coupled and decoupled models. Copyright © 2010 John Wiley & Sons, Ltd.
Constitutive modeling of unsaturated aggregated soils
Authors: Koliji A. , Laloui L. , Vulliet L. 
Published: February 2010

AbstractA coupled water retention–mechanical constitutive model for unsaturated aggregated soils is presented here. Based on the multi‐scale experimental results, the model incorporates the inter‐particle bonding, fabric and partial saturation effects in a single framework. It is formulated within the framework of hardening elasto‐plasticity and is based on the critical state concept. Prior to model validation, we evaluate the model parameters and propose determination procedures for the main new parameters. Finally, the model is examined for its capability in simulating the experimental results of aggregated and bonded soils. Results of these simulations show that the model addresses the most features arising from the combined effects of soil structure and partial saturation. Copyright © 2010 John Wiley & Sons, Ltd.
Smooth particle hydrodynamics simulations of low Reynolds number flows through porous media
Authors: Holmes David W. , Williams John R. , Tilke Peter 
Published: February 2010

AbstractIn this paper, a three‐dimensional smooth particle hydrodynamics (SPH) simulator for modeling grain scale fluid flow in porous media is presented. The versatility of the SPH method has driven its use in increasingly complex areas of flow analysis, including the characterization of flow through permeable rock for both groundwater and petroleum reservoir research. SPH provides the means to model complex multi‐phase flows through such media; however, acceptance of the methodology has been hampered by the apparent lack of actual verification within the literature, particulary in the three‐dimensional case. In this paper, the accuracy of SPH is addressed via a comparison to the previously recognized benchmarks of authors such as Sangani and Acrivos (Int. J. Multiphase Flow1982;8(4): 343–360), Zick and Homsy (J. Fluid Mech.1982;115:13–26) and Larson and Higdon (Phys. Fluids A1989;1(1):38–46) for the well‐defined classical problems of flow through idealized two‐ and three‐dimensional porous media. The accuracy of results for such low Reynolds number flows is highly dependent on the implementation of no‐slip boundary conditions. A new, robust and numerically efficient, method for implementing such boundaries in SPH is presented. Simulation results for friction coefficient and permeability are shown to agree well with the available benchmarks. Copyright © 2010 John Wiley & Sons, Ltd.
On the impact of the scheme for solving the higher dimensional equation in coupled population balance systems
Authors: John Volker , Roland Michael 
Published: February 2010

AbstractPopulation balance systems are models for processes in nature and industry that lead to a coupled system of equations (Navier–Stokes equations, transport equations, etc.) where the equations are defined in domains with different dimensions. This paper will study the impact of using different schemes for solving the three‐dimensional (3D) equation of a precipitation process in a two‐dimensional flow domain. The numerical schemes for the 3D equation are assessed with respect to the median of the volume fraction of the particle size distribution and the computational costs. It turns out that in the case of a structured flow field with small variations in time all schemes give qualitatively the same results. For a highly time‐ dependent flow field, the evolution of the median of the volume fraction differs considerably between first order and higher order schemes. Copyright © 2010 John Wiley & Sons, Ltd.
A geometric integral formulation for eddy‐currents
Authors: Codecasa L. , Specogna R. , Trevisan F. 
Published: February 2010

AbstractIn the computational electromagnetism community it is known how the differential formulation of an eddy‐current problem, can be translated into a finite dimensional system of equations involving circulations and fluxes, by means of the so‐called Discrete Geometric Approach. This is done by exploiting the geometric structure behind Maxwell's equations. In this paper, we will show how the same Discrete Geometric Approach can be profitably used also to discretize an eddy‐current problem formulated in an integral way.We rely on a purely geometric definition of a novel set of face vector basis functions that we use to construct the discrete counterparts—matrices—of both the Ohm's constitutive relation and of the integral relation between the magnetic vector potential and the eddy‐current density vector. The symmetry and positive‐definiteness of such matrices will be demonstrated and their geometric structure will be apparent. Copyright © 2010 John Wiley & Sons, Ltd.
Polymerization of trimethylene carbonate in aqueous solutions: Reaction mechanism and characterization
Authors: Okada Takao , Imamura Yukari , Matsuda Takehisa 
Published: February 2010

AbstractPolymerization of a trimethylene carbonate (TMC) in an aqueous solution was investigated by gel permeation chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance. The polymerization reaction proceeded rapidly in the aqueous solution and high conversion was achieved in a relatively short time. 1,3‐Propanediol (PPD) formed by hydrolysis of TMC was used as the initiator. The TMC oligomer obtained by ring‐opening polymerization had a TMC unit backbone with terminal 3‐hydroxypropyl groups at both chain ends. The oligomer underwent transesterification reaction with elimination of PPD, resulting in a gradual increase in the molecular weight of the product. The molecular weight was affected by the concentration of TMC. The thermal properties of the polymers were investigated by differential scanning calorimetry. Polymers within the molecular weight (Mn) range from 6.0 × 103 to 2.3 × 104 g/mol crystallized, and endothermic peaks corresponding to the melting temperature were observed. The glass transition temperature increased with the molecular weight of the polymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1485–1492, 2010
Stereospecific styrene polymerization and ethylene–styrene copolymerization with titanocenes containing a pendant amine donor
Authors: Son Kyung‐Sun , Waymouth Robert M. 
Published: February 2010

AbstractA series of monocyclopentadienyl titanium complexes containing a pendant amine donor on a Cp group (A = CpTiCl3, B = CpNTiCl3, C = CpNTiCl2TEMPO, for Cp = C5H5, CpN = C5H4CH2CH2N(CH3)2, and TEMPO = 2,2,6,6‐tetramethylpiperidine‐N‐oxyl) are investigated for styrene homopolymerization and ethylene–styrene (ES) copolymerization. When activated by methylaluminoxane at 70 °C, complexes with the amine group (B and C) are active for styrene homopolymerization and afford syndiotactic polystyrene (sPS). The copolymerizations of ethylene and styrene with B and C yield high‐molecular weight ES copolymer, whereas complex A yields mixtures of sPS and polyethylene, revealing the critical role that the pendant amine has on the polymerization behavior of the complexes. Fractionation, NMR, and DSC analyses of the ES copolymers generated from B and C suggest that they contain sPS. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1579–1585, 2010
A new titanium (IV) complex bearing phenoxyimine‐fluorene ligand and its use as catalyst for ethylene homo‐ and copolymerization
Authors: Zhong Liang , Cui Kun , Xie Peng , Chen Jian‐Zhuang , Ma Zhi 
Published: February 2010

AbstractA new titanium (IV) complex bearing phenoxyimine‐fluorene ligand was prepared and its behaviors in ethylene homo‐ and copolymerization with 1‐hexene, 1‐octene, and norbornene in the presence of modified methylaluminoxane (MMAO) were studied respectively. The effects of various polymerization conditions including polymerization temperature, ethylene pressure and the concentration of comonomer on the catalytic activities and properties of the resultant polymer were investigated. The broad molecular weight distribution of resulting polymer indicated that the multiple active species were formed during polymerization. Such complex showed good catalytic activities in ethylene homo‐ and copolymerizations and good capabilities of incorporating various comonomers into polyethylene backbone. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1617–1621, 2010
Controlled synthesis and functionalization of PEGylated methacrylates bearing cyclic carbonate pendant groups
Authors: Jana Satyasankar , Yu Han , Parthiban Anbanandam , Chai Christina L.L. 
Published: February 2010

AbstractHomopolymer bearing cyclic carbonate (CC) group, ABA type triblock copolymers, and (AC)B(AC) type terpolymers with statistical arrangement of A and C monomers bearing side chain CC groups are reported here. Difunctional poly(ethylene glycol) macroinitiators (PEGMIs) were prepared from PEG of three different molecular weights. PEGMIs were subsequently used for the preparation of polymers bearing CC pendant groups from cyclic carbonate methacrylate (CCMA) under atom transfer radical polymerization to yield polymers with low polydispersity index. Homopolymer and ABA type triblock copolymers were obtained by polymerizing CCMA monomer and (AC)B(AC) type statistical terpolymers were obtained when methyl methacrylate was included as a comonomer. No polymer was obtained when styrene was used as comonomer. The cyclic carbonate groups were subjected to ring‐opening reaction with monoamine to yield side chain hydroxyurethane polymers with increased solubility and diamines to yield crosslinked insoluble materials. Changes in wettability characteristics were studied by following the water contact angle of the polymers before and after ring‐opening reaction involving the cyclic carbonate pendant group. The polymers which composed of electrolyte in the form of PEG and coordinating species in the form of pendant cyclic carbonate groups showed conductivity in the range of 2–5 × 10−6 Scm−1 at 23 °C after doping with lithium bis(trifluoromethane)sulfonimide as characterized by impedance spectroscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1622–1632, 2010
Synthesis of poly(vinyl ether) polyols with pendant oxyethylene chains and properties of hydrophilic, thermo‐responsive polyurethanes prepared therefrom
Authors: Hashimoto Tamotsu , Takahashi Ayumi , Urushisaki Michio , Sakaguchi Toshikazu 
Published: February 2010

AbstractHydroxy‐terminated telechelic poly(vinyl ether)s with pendant oxyethylene chains were synthesized by the reaction of the CH3CH(OCOCH3)O[CH2]4OCH(OCOCH3)CH3/Et1.5AlCl1.5/THF‐based bifunctional living cationic polymers of 2‐methoxyethyl vinyl ether (MOVE), 2‐ethoxyethyl vinyl ether (EOVE), and 2‐(2‐methoxyethoxy)ethyl vinyl ether (MOEOVE) with water and the subsequent reduction of the aldehyde polymer terminals with NaBH4. The obtained poly(vinyl ether) polyols were reacted with an equimolar amount of toluene diisocyanates [a mixture of 2,4‐ (80%) and 2,6‐ (20%) isomers] to give water‐soluble polyurethanes. The aqueous solutions of these polyurethanes caused thermally induced precipitation at a particular temperature depending on the sort of the thermosensitive poly(vinyl ether) segments containing oxyethylene side chains. These polyurethanes also function as polymeric surfactants, lowered the surface tension of their aqueous solutions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1641–1648, 2010
Chitosan/silver nanoparticles composite: Molecular relaxations investigation by dynamic mechanical analysis and impedance spectroscopy
Authors: González‐Campos J. Betzabe , Prokhorov Evgen , Luna‐Bárcenas Gabriel , Sanchez Isaac C. , Lara‐Romero Javier , Mendoza‐Duarte M. E. , Villaseñor Francisco , Guevara‐Olvera Lorenzo 
Published: February 2010

AbstractBy impedance spectroscopy, Gonzalez‐Campos et al. J Polym Sci Part B: Polym Phys 2009, 47, 932–943, reported the first evidence of a glass transition in a polysaccharide. To gain a better understanding on the molecular relaxations in polysaccharides, we study composites of chitosan (CS)/silver nanoparticles (AgnP) films by dynamic mechanical analysis (DMA) and dielectric spectroscopy in the 2–250 °C temperature range. CS/AgnP films conductivity increases in two orders of magnitude in comparison with pristine CS. Three relaxation processes ascribed to the α‐relaxation, σ‐relaxation, and degradation process have been observed for the first time. Molecular dynamics and conductivity strongly depends on moisture content; since a plasticizing effect on the glass transition temperature is observed, similarly the increase in AgnP weight percent leads to a glass transition temperature decrease and also increases CS thermal stability. Infrared spectroscopy analysis reveals the AgnPs interaction with OH, NH2, CO.NH2, and COC groups implying an evident redistribution of the vibration bands for these groups. These new bonds affects the molecular dynamics of the CS chain bearing important changes in relaxations processes when compared CS/AgnP composite with pristine CS. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 739–748, 2010