bluuebunny/crossref_metadata_2025_split huggingface dataset:
Addressing difficulties in using XRD intensity for structural study of thin films
Authors: Ramadan A. A. , Abd El‐Mongy A. A. , El‐Shabiny A. M. , Mater A. T. , Mostafa S. H. , El‐Sheheedy E. A. , Hashem H. M. 
Published: July 2008

AbstractThe problem of structure investigation of thin films using laboratory XRD diffraction intensities was discussed as a matter of debate. Is the variation in relative intensities of the diffraction patterns due to crystallographic preferred orientation, lattice defects or both? The answer to this question shows a discrepancy in the literatures. The present work is an attempt to propose a possible approach to judge the most probable answer. Thin films of SnO2 were prepared by spray pyrolysis technique using solution of different SnCl2 concentrations (molarity); at fixed substrate temperature and deposition time. The theoretically calculated integrated intensities together with the experimentally obtained and calculated XRD data (relative intensities, texture coefficients and profile analysis) were considered together in order to get the proper picture of the structure characteristics of the prepared films. The complete picture can be assembled by integration and correlation of all the crystallographic information that are extracted from the diffraction pattern including not only the observed intensities but also the size/strain analysis and lattice parameters. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
X‐ray diffraction refinement of the crystal structure of anosovite prepared from leucoxene
Authors: Grass V. , Istomin P. , Nazarova L. 
Published: July 2008

AbstractThe crystal structure of anosovite, (Ti1.69Al0.26Fe0.05)3+(Ti0.97Zr0.03)4+O5, prepared by carbothermal reduction of leucoxene under vacuum at 1450°C has been refined by Rietveld method using powder X‐ray diffraction data. It was found that it represents slightly monoclinically deformed pseudobrookite type structure with lattice parameters a = 9.8111 Å, b = 3.7509 Å, c = 9.9468 Å, β = 90.628°. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, characterization and crystal structure of a porous crystalline material
Authors: Zhou Chun‐Sheng , Zhang Guo‐Chun 
Published: July 2008

AbstractAn exploration of the nickel‐malate‐bpp system under hydrothermal conditions, has led to the isolation of a novel framework {[Ni(Hmal)(bpp)]·5H2O}n (1) (Hmal = malate dianion, bpp = 1,3‐bi(4‐pyridyl)propane). Single‐crystal X‐ray analyses reveal that it crystallizes in the orthorhombic space group Pccn. a = 21.141(3) Å, b = 10.4028(16) Å, c = 19.250(3) Å. The Ni(II) ions are linked into an extended helical chain via Hmal molecules. Further these chains are united together through the bridging bpp to form a 3D porous framework, which exhibits an unusual NbO‐type topological network. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cross‐sectional and surface Raman mapping of thick GaN layers
Authors: Korbutowicz R. , Tłaczała M. , Kovač J. , Irmer G. , Srnanek R. 
Published: July 2008

AbstractRaman scattering spectroscopy was utilized for investigation of the structural properties of thick GaN layers. These layers with thickness ∼ 40 μm have been grown by HVPE technique on the sapphire substrates. The investigations have been focused on the strain distribution in GaN layer cross‐section as a function of distance from an interface sapphire/GaN and mapping of the surface and of the inner layer, near the sapphire/GaN interface. From the observed phonon shifts in the Raman spectra strain differences lower than 6.4×10–4corresponding to stress differences of 240 MPa were estimated across the thick GaN epitaxial layer. The measurements exhibit that strain in the layer causes changes in the Raman spectra and allow determining the relaxation process in the crystal. The obtained results confirmed, that the mode frequencies in the measured Raman spectra in both directions (parallel or perpendicular to the growth direction) for layer thicknesses over 30 µm are comparable with typical values for bulk material and match the low strain in the structure due to relaxation processes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of reactive DC magnetron sputtered TiAlN thin films
Authors: Subramanian B. , Ashok K. , Kuppusami P. , Sanjeeviraja C. , Jayachandran M. 
Published: July 2008

AbstractThin films of about 1μm Titanium Aluminum Nitride (TiAlN) were deposited onto mild steel substrates by reactive direct current (DC) magnetron sputtering using a target consisting of equal segments of titanium and aluminum. X‐ray diffraction (XRD) analysis showed that the TiAlN phase had preferred orientations along 111 and 200 with the face‐centered cubic structure. Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) analyses indicated that the films were uniform and compact. Photoluminescence (PL) spectra reveal that TiAlN thin films are of good optical quality. Laser Raman studies revealed the presence of characteristic peaks of TiAlN at 312.5, 675, and 1187.5 cm–1. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adaptive synchronization of GLHS with unknown parameters
Authors: Wang Yan‐Wu , Guo Li‐Lin , Xiao Di , Xiao Jiang‐Wen 
Published: July 2008

AbstractIn this paper, an adaptive controller for the synchronization of two generalized Lorenz hyperchaos systems (GLHSs) is designed by using the Lyapunov method. In the synchronization schema, the parameters of the drive system are unknown and different from those of the response system. By introducing update laws for both the control coefficients and the parameters of the response system, the adaptive controller proposed in this paper is brand new compared with the former relative works. The proposed adaptive controller is feasible for any possible parameters of GLHS. Numerical simulation is carried out to verify and illustrate the analytical result. Copyright © 2008 John Wiley & Sons, Ltd.
Circuit theory of paralleling switching converters
Authors: Huang Yuehui , Tse Chi K. 
Published: July 2008

AbstractThis paper studies the various paralleling styles for dc–dc switching converters from a circuit theoretic viewpoint. The study begins with a systematic classification of the types of parallel‐connected dc–dc converters. In the classification, converters are modeled as current sources or voltage sources. From Kirchhoff's laws, the possible connection styles for paralleling current sources and voltage sources are derived, leading to the identification of three types of configurations for paralleling dc–dc converters. Then, control arrangements are classified according to the presence of current‐sharing and voltage‐regulation loops. Moreover, detailed operating principles with and without a current‐sharing loop for the three basic paralleling connections to obtain both current sharing and voltage regulation are given. Applying small‐signal analysis to the practical circuits, the inherent characteristics of each scheme are expounded. The roles of the current‐sharing loop and origins of current‐sharing errors are highlighted. Characteristics for all the schemes are obtained in terms of their performances in current sharing and voltage regulation. Finally, an experiment prototype is built to validate the analysis. The results clearly show the properties of the various paralleling schemes. Copyright © 2008 John Wiley & Sons, Ltd.
Crystal Structure, Electronic Structure, and Solid‐State Electrochemistry of Cluster Complexes of M3Se74+(M = Mo, W) with Noninnocento‐Phenanthroline and Se22–Ligands
Authors: Gushchin Artyom L. , Sokolov Maxim N. , Peresypkina Eugenia V. , Virovets Alexandr V. , Kozlova Svetlana G. , Zakharchuk Nina F. , Fedin Vladimir P. 
Published: July 2008

AbstractThe crystal, molecular, and electronic structure as well as the electrochemical behavior ofo‐phenanthroline complexes [M3Se7(o‐phen)3]X4(M = Mo, W; X = Cl, Br) were investigated. Recrystallization of [Mo3Se7(o‐phen)3]Br4from concentrated hydrochloric acid gave crystals corresponding to [Mo3(μ3‐Se)(μ2‐Se2)3(o‐phen)3]Cl4·12H2O, for which X‐ray analysis was performed. The bromide is isostructural. Solid‐state cyclic voltammetry shows that [M3Se7(o‐phen)3]Br4(M = Mo, W) undergoes reversible three‐electron reduction, which is phen‐centered with strong delocalization on the metal. DFT calculations for {[Mo3Se7(o‐phen)3]Br}3+, [Mo3Se7(o‐phen)3]4+, and {[Mo3Se7(o‐phen)3]Br}0support the correct formulation of the reduction process. Strong interactions between the Cl–or Br–and Se2ligands of the M3Se7cluster, observed in the crystal, can be described as donor–acceptor covalent bonding and are important enough to influence the redox behavior of the cluster.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Low‐Coordinate Iron Complexes Based on Bis(pyrazolyl)borate and Their Reactivity
Authors: Wagner Marit , Limberg Christian , Ziemer Burkhard 
Published: July 2008

AbstractPreparation routes for several sodium salts of diphenylbis(pyrazolyl)borates with bulky substituents are described. For a potential modelling of α‐keto‐acid‐dependent nonheme iron enzymes, mononuclear iron compounds containing those bis(pyrazolyl)borates as ligands were synthesised and structurally characterised. The iron centres are four‐coordinate (in one case only three‐coordinate) thus offering room for the binding of exogenous ligands. However, reactivity studies with carboxylates and O2 have revealed nonuniform behaviour, and the identification of a side product in one case, combined with subsequent ESI‐MS studies, demonstrated that a pronounced sensitivity of the B–N bonds towards oxo nucleophiles could be a possible reason.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A T‐Shaped μ3‐Oxido Trinuclear Iron Cluster with High Easy‐Plane Anisotropy: Structural and Magnetic Characterization
Authors: Alborés Pablo , Rentschler Eva 
Published: July 2008

AbstractThe synthesis, crystal structure and magnetochemical characterization of a new μ‐oxido trinuclear iron cluster (oldnomenclature: μ‐oxo trinuclear iron cluster), [Fe3(μ3‐O)(μ2‐CH3O)2(μ2‐CH3COO)2(phen)2Cl3], is reported. The reaction of hydrated FeCl3 with sodium acetate and 1,10‐phenanthroline in a mixture of methanol and acetonitrile afforded crystals suitable for X‐ray crystallographic determination. The new compound crystallizes in the tetragonal I41/a space group (a = b = 13.6322 Å, c = 37.3538 Å, Z = 8, V = 6941.7 Å3). The core of the complex is an isosceles triangle bridged by a μ3‐O ion with a rare T‐shaped geometry. The chloride ions are bound terminally, and the phenanthroline ligands are π‐stacked. Variable‐temperature solid‐state dc magnetization studies were carried out in the 2.0–300 K range. Data were fit with an isotropic Heisenberg spin Hamiltonian, which included an axial anisotropy (zero‐field splitting) term. Two antiferromagnetic exchange parameters for the isosceles triangle arrangement of the iron ion were needed, with values of –11.2 and –47.7 cm–1, while a positive D value of about 1.5 cm–1 was obtained. In addition, magnetization (M) vs. field (H) and temperature (T) data established an ST = 5/2 ground‐state spin. We also performed broken‐symmetry DFT calculations, which reproduced the experimental J values and the ground‐state spin well. The replacement of one Fe3+ ion by a Ga3+ ion allowed for simplification of the three‐centre problem to one treating a dinuclear exchange‐coupled system, and this afforded good computed values. To the best of our knowledge, this is the first time that this specific replacement has been applied within broken‐symmetry DFT calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis and Characterization of CoFe2O4 Hollow Spheres
Authors: Meng Yongde , Chen Dairong , Jiao Xiuling 
Published: July 2008

AbstractCoFe2O4 hollow spheres with sizes ranging from 600 nm to 1 μm were prepared through hydrothermal treatment of an aqueous solution containing glucose, ammonium iron(II) sulfate hexahydrate [(NH4)2Fe(SO4)2·6H2O], and cobalt(II) sulfate heptahydrate [CoSO4·7H2O], followed by calcination. The wall of the CoFe2O4 hollow spheres is composed of CoFe2O4 spinel nanoparticles with a size of ca. 30 nm and wall thickness of ca. 150 nm. Magnetic characterization indicates high coercivity and low saturation magnetization, which indicate potential applications as high‐density magnetic recording materials and drug carriers.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
The Use of Halide‐Substituted Anilines for the Formation of Magnesium Imides
Authors: Rood Jeffrey A. , Hinman Sondra E. , Noll Bruce C. , Henderson Kenneth W. 
Published: July 2008

AbstractThe equimolar reactions of the halide‐substituted anilines 2,4,6‐trichloroaniline (ArClNH2) and 2,3,4,5,6‐pentafluoroaniline (ArFNH2) with Bu2Mg in the appropriate solvent system results in the formation of the magnesium imide compounds [(ArClNMg·thf)4·tol] (4), [(ArClNMg·diox)4·3diox] (5), [(ArFNMg·thf)6·3C6H6] (6) and [(ArFNMg·diox)6] (7). Single‐crystal X‐ray diffraction analyses show that 4 and 5 adopt tetrameric cubane arrangements in the solid state, whereas 6 and 7 form prismatic hexameric aggregates. In comparison, reaction of 2 mol‐equiv. of ArFNH2 with Bu2Mg produces the trimeric primary amide species [{(ArFNH)6Mg3·(thf)6}·2tol·thf] (9). In addition, the serendipitous synthesis of the decametallic imide [(ArFN)9(F)2Mg10(thf)6·1.25tol] (8a) and the structural isomer [(ArFN)9(F)2Mg10(thf)6·4.5tol] (8b) were discovered during the attempted synthesis of 6. It is presumed that the formation of these unusually large cage compounds results from the partial decomposition of the imide ligand by C–F bond cleavage. The compounds 8a and 8b have similar core‐cage structures, but the orientation of their aryl groups and coordinated solvent molecules vary. The 20‐vertex Mg10N9F aggregates utilize one fluoride ion as a vertex, with a second fluoride ion encapsulated within the cage. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Nucleohomolytic Substitution at Boron: A Computational Approach
Authors: Carra Claudio , Scaiano Juan C. 
Published: July 2008

AbstractA theoretical investigation is reported on the reaction mechanism for oxygen‐centered radical attack on alkyl‐ and arylborane substrates. The model reveals how the mechanism, traditionally considered as a SH2 reaction, involves instead nucleophilic attack of the oxygen lone pair on the empty boron p orbital. The single electron on the oxygen is not directly involved in the process, however, as a result of a stereoelectronic effect: the bond aligned with the SOMO orbital is deactivated and the corresponding ligand leaves promptly as a radical species. The overall mechanism can be described as a nucleohomolytic reaction that shares many characteristics with conventional nucleophilic substitution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Copper‐Catalyzed Cross‐Coupling of Thiols with 1‐Iodo‐2‐chalcogenoalkenes
Authors: Manarin Flávia , Roehrs Juliano A. , Wilhelm Ethel A. , Zeni Gilson 
Published: July 2008

AbstractWe describe herein a new method for the synthesis of densely substituted alkenes containing chalcogenide atoms by a cross‐coupling reaction between 1‐iodo‐2‐chalcogenoalkenes and thiols using copper(I) as catalyst in a ligand‐free system. The desired cross‐coupling products were obtained in good yields and with satisfactory selectivity. The developed protocol tolerates a wide range of functional groups; the reactions of alkyl‐, benzyl‐, and arylthiols with neutral, electron‐deficient, and electron‐rich substituents on the aromatic ring were explored in the absence of any supplementary additives. In addition, the reaction proceeded cleanly under mild reaction conditions and was sensitive to the nature of the catalyst, base, and solvent.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Application and comparison of wind speed sampling methods for wind generation in reliability studies using non‐sequential Monte Carlo simulations
Authors: Vallée F. , Lobry J. , Deblecker O. 
Published: July 2008

AbstractGiven the actual context of increased dispersed generation and highly loaded lines, probabilistic methods are more and more required to take into account the stochastic behavior of electrical network components (possible spate of outages by use of the electrical network near its physical limits) in reliability studies. To implement those probabilistic methods, numerical Monte Carlo simulations are typically used and can be divided in two categories: sequential and non‐sequential techniques.This paper deals with two wind speed sampling methods adapted for non‐sequential Monte Carlo simulations, among which an original approach based on the combination of a mean statistical law (for a large geographical area like a country) and Normal distributions (to characterize smaller wind speed zones inside the country). Both proposed techniques are then applied on a self‐developed non‐sequential Monte Carlo simulation only taking into account generation units outages and load changes (hierarchical level HL‐I). Finally, the collected simulation results allow, not only, to evaluate the impact of sampling methods on the collected reliability indices but also to decide which proposed technique will lead to the most interesting situations (larger wind power fluctuations from one state to the other) for the electrical network operation management. Note that our simulations are applied to the Belgian production park. Copyright © 2008 John Wiley & Sons, Ltd.
Computational stochastic heat transfer with model uncertainties in a plasterboard submitted to fire load and experimental validation
Authors: Sakji S. , Soize C. , Heck J.‐V. 
Published: July 2008

AbstractThe paper deals with probabilistic modeling of heat transfer throughout plasterboard plates when exposed to an equivalent ISO thermal load. The proposed model takes into account data and model uncertainties. This research addresses a general need to perform robust modeling of plasterboard‐lined partition submitted to fire load. The first step of this work concerns the development of an experimental thermo physical identification data base for plasterboard. These experimental tests are carried out by the use of a bench test specially designed within the framework of this research. A computational heat transfer model is constructed using data from the literature and also the identified plasterboard thermophysical properties. The developed mean model constitutes the basis of the computational stochastic heat transfer model that has been constructed employing the nonparametric probabilistic approach. Numerical results are compared to the experimental ones. Copyright © 2008 John Wiley & Sons, Ltd.
Subventricular zone microglia possess a unique capacity for massive in vitro expansion
Authors: Marshall Gregory P. , Demir Meryem , Steindler Dennis A. , Laywell Eric D. 
Published: July 2008

AbstractMicroglia, the resident immune cells of the brain, have recently been hypothesized to play a role both in neuronal diseases and age‐related neurogenic decline, and are theorized to be modulators of adult neurogenesis. Current methods for the isolation of microglia from cultured primary brain tissue result in relatively poor yield, requiring a large tissue sample or multiple specimens to obtain a sufficient number of microglia for cell and molecular analysis. We report here a method for the repetitive isolation of microglia from established glial monolayer cultures from which it is possible to expand the initial population of microglia roughly 10,000‐fold. The expanded population expresses appropriate microglial morphology and phenotype markers, and demonstrates functionally normal phagocytosis, thus providing a high‐yield assay for the investigation and analysis of microglia from a single initial dissection of primary tissue. Furthermore, this massive expansion is limited to microglia derived from the subventricular zone as the fold expansion of isolatable microglia was found to be up to 20 times greater than cultures from other brain regions, indicating unique properties for this persistently neurogenic region. © 2008 Wiley‐Liss, Inc.
Neuroprotective effects of human mesenchymal stem cells on dopaminergic neurons through anti‐inflammatory action
Authors: Kim You‐Joung , Park Hyun‐Jung , Lee Gwang , Bang Oh Young , Ahn Young Hwan , Joe Eunhye , Kim Hyun Ok , Lee Phil Hyu 
Published: July 2008

AbstractParkinson's disease (PD) is a common, progressive neurodegenerative disorder caused by the loss of dopaminergic neurons in the substantia nigra (SN). Numerous studies have provided evidence suggesting that neuroinflammation plays an important role in the pathogenesis of PD. In this study, we used lipopolysaccharide (LPS)‐induced in vitro and in vivo inflammation models to investigate whether human mesenchymal stem cells (hMSCs) have a protective effect on the dopaminergic system through anti‐inflammatory mechanisms. The hMSC treatment significantly decreased LPS‐induced microglial activation, tumor necrosis factor (TNF)‐α, inducible nitric oxide synthase (iNOS) mRNA expression, and production of NO and TNF‐α compared with the LPS‐only treatment group. In co‐cultures of microglia and mesencephalic dopaminergic neurons, hMSC treatment significantly decreased the loss of tyrosine hydroxylase‐immunopositive (TH‐ip) cells. The hMSC treatment in rats showed that TH‐ip neuronal loss induced by LPS stimulation in the SN was considerably decreased and was clearly accompanied by a decrease in activation of microglia, as well as TNF‐α and iNOS mRNA expression and production of TNF‐α. These data suggest that hMSCs have a neuroprotective effect on dopaminergic neurons through anti‐inflammatory actions mediated by the modulation of microglial activation. Along with various trophic effects and trans‐differentiational potency, the anti‐inflammatory properties of MSCs could have major therapeutic implications in the treatment of PD. © 2008 Wiley‐Liss, Inc.
Oxidized low‐density lipoprotein induces matrix metalloproteinase‐9 expression via a p42/p44 and JNK‐dependent AP‐1 pathway in brain astrocytes
Authors: Wang Hui‐Hsin , Hsieh Hsi‐Lung , Wu Cheng‐Ying , Sun Chi‐Chin , Yang Chuen‐Mao 
Published: July 2008

AbstractUpregulation of matrix metalloproteinases (MMPs), especially MMP‐9, by oxidized low‐density lipoprotein (oxLDL) is implicated in many inflammatory diseases including brain injury. However, the signaling mechanisms underlying oxLDL‐induced MMP‐9 expression in astrocytes largely remain unknown. Here we report that oxLDL induces expression of proMMP‐9 via a MAPK‐dependent AP‐1 activation in rat brain astrocyte (RBA)‐1 cells. Results revealed by gelatin zymography, RT‐PCR, and Western blotting analyses showed that oxLDL‐induced proMMP‐9 gene expression was mediated through Akt, JNK1/2, and p42/p44 MAPK phosphorylation in RBA‐1 cells. These responses were attenuated by inhibitors of PI3K (LY294002), JNK (SP600125), and p42/p44 MAPK (PD98059), or transfection with dominant negative mutants and short hairpin RNA. Moreover, we demonstrated that AP‐1 (i.e., c‐Fos/c‐Jun) is crucial for oxLDL‐induced proMMP‐9 expression which was attenuated by pretreatment with AP‐1 inhibitor (curcumin). The regulation of MMP‐9 gene transcription by AP‐1 was confirmed by oxLDL‐stimulated MMP‐9 luciferase activity which was totally lost in cells transfected with the AP‐1 binding site‐mutatedMMP‐9promoter construct (mt‐AP1‐MMP‐9). These results suggested that oxLDL‐induced proMMP‐9 expression is mediated through PI3K/Akt, JNK1/2, and p42/p44 MAPK leading to AP‐1 activation. Understanding the regulatory mechanisms underlying oxLDL‐induced MMP‐9 expression in astrocytes might provide a new therapeutic strategy of brain injuries and diseases. © 2008 Wiley‐Liss, Inc.