bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of methylammonium tetrachlorocuprate (II) dihydrate crystals
Authors: Amirthaganesan G. , Kandhaswamy M. A. , Dhandapani M. 
Published: June 2007

AbstractSingle crystals of methylammonium tetrachlorocuprate (II) dihydrate were obtained by slow evaporation method at room temperature. The crystals were characterized through powder XRD, thermogravimetric (TG‐DTA), low temperature DSC studies and FTIR and far IR spectra. While the powder XRD confirms the crystallinity of the compound, the TG and DTA studies confirm the formation of the compound in the stoichiometric ratio and the presence of two water molecules of crystallization. The low temperature DSC study indicates a thermal anomaly at ‐3°C. The ordering of CH3NH3 group at low temperature causes phase transitions in the compound. The IR spectra characterize the various chemical bonding and water molecules in the compound. Laser Raman spectral studies under progress would help understand the mechanism of phase transitions at low temperatures. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical and electrical studies on spray deposited ZnO thin films
Authors: Sahay P. P. , Tewari S. , Nath R. K. 
Published: June 2007

AbstractZnO thin films were prepared by spray pyrolytic decomposition of zinc acetate onto a glass substrate. These films were analyzed for the optical and electrical properties. Optical studies show that in these films the electronic transition is of the direct transition type. The optical energy gap for the films of different thicknesses is estimated to be in the range 2.98 – 3.09 eV. Electrical studies indicate that the films exhibit thermally activated electronic conduction and the activation energies are found to be dependent on the film thickness. The complex impedance measurements were carried out over a wide range of frequencies at room temperature (300 K). All the impedance spectra contain only a single arc, but the arc has a non‐zero intersection with the real axis in the high frequency region. Also, the arc has its centre lying below with the real axis which indicates the multirelaxation behavior of the films. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of Mg/Er co‐doping on the principal laser parameters of LiNbO3 crystals
Authors: Sun Liang , Yu Haitao , Lv Qiang , Guo Fengyun , Li Hongtao , Cai Wei , Xu Yuheng , Zhao Liancheng 
Published: June 2007

AbstractMg: Er: LiNbO3 crystals were grown by the Czochralski technique with various concentrations of MgO = 2 mol%, 4 mol%, 6 mol% and the fixed concentration of Er2O3= 1 mol% in the melt, and the 8 mol%Mg: 1 mol%Er: LiNbO3 crystal was fabricated by the Czochralski technique with special technology process. The crystals were treated by polarization, reduction and oxidation. The segregation coefficients of Mg2+ and Er3+ in Mg: Er: LiNbO3 crystals were measured by X‐ray fluorescence spectrograph, as well as the crystal's defect structure and optical properties were analyzed by the UV‐Vis, IR and fluorescent spectroscopy. The pump wavelength and the surge wavelength were determined. Using m‐line method tested optical damage resistance of those crystals, the results show that photodamage threshold of Mg: Er: LiNbO3 crystals are higher than that of Er: LiNbO3 crystal, and the oxidation treat could enhance the photodamage resistant ability of crystals while the reduction treat could depress the ability. The optical damage resistance of 8 mol%Mg: 1 mol%Er: LiNbO3 crystal was the strongest among the samples, which was two orders magnitude higher than that of 1 mol%Er: LiNbO3 crystal. The dependence of the optical properties on defect structure of Mg: Er: LiNbO3 crystals was discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermodynamic Functions for Plasmas Beyond Montroll Ward
Authors: Kraeft W.‐D. , Vorberger J. , Gericke D. O. , Schlanges M. 
Published: June 2007

AbstractWe present an approach to the equation of state of fully ionized plasmas with any coupling strength. For this reason we go beyond the Montroll‐Ward contribution. The latter describes the thermodynamic functions at any degeneracy, but it only includes terms up to the order e4 with respect to the coupling strength. Therefore, we combine the Montroll‐Ward contribution and the corresponding exchange contribution up to the order e4 with classical hypernetted chain (HNC) calculations. The improvements made by the application of quantum pseudo‐potentials in the latter approach are discussed. Furthermore, a detailed analysis shows which terms must be omitted in the combined approach since they are included in both the Montroll‐Ward and the classical HNC contribution. Results for a hydrogen plasma are finally compared with simulation data and other theoretical results. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effective Polarization Potential and Scattering Processes in a Partially Ionized Plasma
Authors: Ramazanov T. S. , Dzhumagulova K.N. , Omarbakiyeva Y.A. , Röpke G. 
Published: June 2007

AbstractElastic cross sections of electrons on atoms were investigated in the framework of a pseudopotential interaction model. Within a partial wave expansion, the scattering phase shifts are determined, and total and differential cross sections were obtained. The bremsstrahlung cross section for electron collisions with neutral atoms is evaluated. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shell Structure of Yukawa Balls
Authors: Baumgartner H. , Kählert H. , Golobnychiy V. , Henning C. , Käding S. , Melzer A. , Bonitz M. 
Published: June 2007

AbstractSpherical crystals continue to attract increasing interest in many fields, including trapped ions and dusty plasmas. These strongly coupled systems are excellent objects to study fundamental interactions and interesting correlation phenomena while they are relatively easy to realize and observe. Experiments and simulations show a spherical arrangement in nested shells. This work discusses new experimental and simulation results for small systems (N ≤ 54) as well as the influence of temperature and charge fluctuations on the shell populations. Finally, the cluster configurations are compared with an analytical shell model which is able to predict shell populations and energies for larger clusters. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shift of Cl Kαand KβLines in Laser Produced Dense Plasmas
Authors: Sengebusch A. , Glenzer S. H. , Kritcher A. L. , Reinholz H. , Röpke G. 
Published: June 2007

AbstractThe features of chlorine K‐lines have been investigated to develop X‐ray probes for Compton scattering on warm dense plasmas. The shapes of these spectral lines have been studied at different laser energies by irradiation of thin saran foils by an intense ultra‐short‐pulse laser beam. The observed positions of Kαand Kβlines undergo a red shift due to a laser induced plasma environment. With increasing intensities the shift changes direction and turns into a blue shift caused by a higher contribution of K‐transitions occuring in further excited or ionized atoms. A theoretical approach based on the self‐consistent ion sphere model is outlined to describe this inversion. Plasma polarization effects are taken into account as well as different ionization stages of the X‐ray emitter within a warm dense plasma. Calculations using an improved ion sphere ansatz show good agreement with observations of the line shifts. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hypernetted Chain Calculations for Two‐Component Plasmas
Authors: Schwarz V. , Bornath Th. , Kraeft W.‐D. , Glenzer S. H. , Höll A. , Redmer R. 
Published: June 2007

AbstractWe have performed HNC calculations for dense beryllium plasma as studied experimentally using x‐ray Thomson scattering, recently. We treated non‐equilibrium situations with different electron and ion temperatures which are relevant in pump‐probe experiments on ultra‐short time scales. To consider quantum effects adequately, we used effective pair potentials to describe the interactions. Results are compared with classical as well as quantum corrected Debye model calculations. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Hall Effect in Dense Noble Gas Plasmas
Authors: Adams J. R. , Reinholz H. , Redmer R. , Shilkin N. S. , Mintsev V. B. , Gryaznov V. K. 
Published: June 2007

AbstractIn recent years, noble gas plasmas in magnetic fields have been investigated. Experimental results for the Hall coefficient have been made available. We compare these with results calculated using linear response theory in the Zubarev formalism. In this work, we investigate the possibility of using Hall voltage measurements to determine the electron concentration of partially ionized plasmas. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystallization in Mass‐Asymmetric Electron‐Hole Bilayers
Authors: Ludwig P. , Filinov A. , Lozovik Yu. E. , Stolz H. , Bonitz M. 
Published: June 2007

AbstractWe consider a mass‐asymmetric electron and hole bilayer. Electron and hole Coulomb correlations and electron and hole quantum effects are treated on first principles by path integral Monte Carlo methods. For a fixed layer separation we vary the mass ratio M of holes and electrons between 1 and 100 and analyze the structural changes in the system. While, for the chosen density, the electrons are in a nearly homogeneous state, the hole arrangement changes from homogeneous to localized, with increasing M, which is verified for both, mesoscopic bilayers in a parabolic trap and for a macroscopic system. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of the Ion Temperature in a Plasma Created by Optical Field Ionization
Authors: Maynard G. , Lambert F. , Andreev N. , Robillar B. , Boudaa A. , Clerouin J. , Cros B. , Lenglet A. , Mocek T. , Sebban S. 
Published: June 2007

AbstractThe evolution with time of the ion temperature of a xenon gas during and after the irradiation with a high intensity laser beam is determined. The processes taken into account are (i) direct interaction with the laser beam, (ii) binary collisions with hot electrons, (iii) contribution with the electrostatic wakefield, (iv) hydrodynamic expansion and (v) transfer of potential to kinetic energy among the plasma ions. It is shown that, because the ions are strongly coupled, the last process is by far the most efficient one. Using the One Component Plasma (OCP) model, a simple analytical formula for the ion temperature at equilibrium is obtained. Application of this work to the development of soft x‐ray laser sources is stressed out. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Free‐Electron Generation in Laser‐Irradiated Dielectrics
Authors: Rethfeld B. 
Published: June 2007

AbstractWhen transparent solids are irradiated with laser or particle beams an electron‐hole plasma may be generated, which consists of free electrons in the conduction band of the solid and holes in the valence band. If the electron density reaches values close to the critical plasma density (at which the plasma frequency of the free electron gas equals the laser frequency), the dielectric becomes highly absorbing. The large energy transfer to the solid leads to dielectric breakdown and further to phase transitions and ablation. We compare different models describing the temporal evolution of the free‐electron density under laser irradiation. The role of different ionization processes is investigated in dependence on laser pulse duration and intensity. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transgenic mice expressing a dual, CRE‐inducible reporter for the analysis of axon guidance and synaptogenesis
Authors: Badaloni Aurora , Bonanomi Dario , Albieri Ilaria , Givogri Irene , Bongarzone Ernesto , Valtorta Flavia , Consalez G. Giacomo 
Published: June 2007

AbstractImproved and modular tools are needed for the neuroanatomical dissection of CNS axonal tracts, and to study the cell‐intrinsic and cell‐extrinsic cues that govern their assembly and plasticity. Here we describe a general purpose transgenic tracer that can be used to visualize axonal tracts and synaptic terminals in any region of the embryonic neural tube or postnatal CNS, on any wild type or mutant genetic background. The construct permits CRE‐inducible expression of a dicistronic axonal marker encoding two surface reporter proteins: a farnesylated GFP and the human Placental Alkaline Phosphatase (PLAP). Both proteins localize alongside the neuronal surface, permitting the concomitant detection of cell body, neurites, and presynaptic and postsynaptic sites in the same neuron. This provides a CRE‐inducible dual system for imaging neural circuits in vivo, and to study their assembly and remodeling in cultured neurons, neural stem cells, and tissue explants derived from the reporter line. Unlike existing lines, this reporter does not encode a ubiquitously expressed, floxable LacZ gene, permitting the simultaneous analysis of beta galactosidase activity in mutant lines. genesis 45:405–412, 2007. © 2007 Wiley‐Liss, Inc.
Completeness, conservation and error in SPH for fluids
Authors: Vaughan G. L. , Healy T. R. , Bryan K. R. , Sneyd A. D. , Gorman R. M. 
Published: June 2007

AbstractSmoothed particle hydrodynamics (SPH) is becoming increasingly common in the numerical simulation of complex fluid flows and an understanding of the errors is necessary. Recent advances have established techniques for ensuring completeness conditions (low‐order polynomials are interpolated exactly) are enforced when estimating property gradients, but the consequences on errors have not been investigated. Here, we present an expression for the error in an SPH estimate, accounting for completeness, an expression that applies to SPH generally. We revisit the derivation of the SPH equations for fluids, paying particular attention to the conservation principles. We find that a common method for enforcing completeness violates a property required of the kernel gradients, namely that gradients with respect the two position variables be equal and opposite. In such models this means conservation principles are not enforced and we present results that show this. As an aside we show the summation interpolant for density is a solution of, and may be used in the place of, the discretized, symmetrized continuity equation. Finally, we examine two examples of discretization errors, namely numerical boundary layers and the existence of crystallized states. Copyright © 2007 John Wiley & Sons, Ltd.
Simulation of transient gas flow at pipe‐to‐pipe intersections
Authors: Herty Michael , Seaïd Mohammed 
Published: June 2007

AbstractWe numerically investigate a well‐established mathematical model for gas flow in pipeline networks. The emphasis is given to the description of coupling conditions at pipe‐to‐pipe intersections. The accurate prediction of these coupling conditions is essential in order to achieve good performance and reliable numerical simulations of network simulations. Nowadays, a variety of theoretical results for a reduced geometry exists. We conduct a numerical simulation of the two‐dimensional representation at a pipe intersection. The results are used for verification and comparison with known theoretical results. High‐order and non‐oscillatory discretizations are used for solving the governing equations of gas flow. Verifications are conducted for two types of junctions to analyse the most adequate coupling conditions. Copyright © 2007 John Wiley & Sons, Ltd.
A simple high‐resolution advection scheme
Authors: Mingham C. G. , Causon D. M. 
Published: June 2007

AbstractA simple, robust, mass‐conserving numerical scheme for solving the linear advection equation is described. The scheme can estimate peak solution values accurately even in regions where spatial gradients are high. Such situations present a severe challenge to classical numerical algorithms. Attention is restricted to the case of pure advection in one and two dimensions since this is where past numerical problems have arisen. The authors' scheme is of the Godunov type and is second‐order in space and time. The required cell interface fluxes are obtained by MUSCL interpolation and the exact solution of a degenerate Riemann problem. Second‐order accuracy in time is achieved via a Runge–Kutta predictor–corrector sequence. The scheme is explicit and expressed in finite volume form for ease of implementation on a boundary‐conforming grid. Benchmark test problems in one and two dimensions are used to illustrate the high‐spatial accuracy of the method and its applicability to non‐uniform grids. Copyright © 2007 John Wiley & Sons, Ltd.
Identifying technically efficient fishing vessels: a non‐empty, minimal subset approach
Authors: Flores‐Lagunes Alfonso , Horrace William C. , Schnier Kurt E. 
Published: June 2007

AbstractStochastic frontier models are often employed to estimate fishing vessel technical efficiency. Under certain assumptions, these models yield efficiency measures that are means of truncated normal distributions. We argue that these measures are flawed, and use the results of Horrace (2005) to estimate efficiency for 39 vessels in the Northeast Atlantic herring fleet, based on each vessel's probability of being efficient. We develop a subset selection technique to identify groups of efficient vessels at pre‐specified probability levels. When homogeneous production is assumed, inferential inconsistencies exist between our methods and the methods of ranking the means of the technical inefficiency distributions for each vessel. When production is allowed to be heterogeneous, these inconsistencies are mitigated. Copyright © 2007 John Wiley & Sons, Ltd.
Phylogenetic relationships of Danio within the order Cypriniformes: a framework for comparative and evolutionary studies of a model species
Authors: Mayden Richard L. , Tang Kevin L. , Conway Kevin W. , Freyhof Jörg , Chamberlain Sarah , Haskins Miranda , Schneider Leah , Sudkamp Mitchell , Wood Robert M. , Agnew Mary , Bufalino Angelo , Sulaiman Zohrah , Miya Masaki , Saitoh Kenji , He Shunping 
Published: June 2007

AbstractThe evolutionary relationships of species of Danio and the monophyly and phylogenetic placement of the genus within the family Cyprinidae and subfamily Rasborinae provide fundamentally important phyloinformatics necessary for direct evaluations of an array of pertinent questions in modern comparative biology. Although the genus Danio is not one of the most diverse within the family, Danio rerio is one of the most important model species in biology. Many investigations have used this species or presumed close relatives to address specific questions that have lasting impact on the hypothesis and theory of development in vertebrates. Largely lacking from this approach has been a holistic picture of the exact phylogenetic or evolutionary relationships of this species and its close relatives. One thing that has been learned over the previous century is that many organismal attributes (e.g., developmental pathways, ecologies, behaviors, speciation) are historically constrained and their origins and functions are best explained via a phylogenetic approach. Herein, we provide a molecular evaluation of the phylogenetic placement of the model species Danio rerio within the genus Danio and among hypothesized closely related species and genera. Our analysis is derived from data using two nuclear genes (RAG1, rhodopsin) and five mitochondrial genes (ND4, ND4L, ND5, COI, cyt b) evaluated using parsimony, maximum likelihood, and Bayesian analyses. The family Cyprinidae is resolved as monophyletic but the subfamily Rasborinae (priority over Danioinae) is an unnatural assemblage. Danio is identified as a monophyletic group sister to a clade inclusive of the genera Chela, Microrasbora, Devario, and Inlecypris, not Devario nor Esomus as hypothesized in previous studies. Danio rerio is sister to D. kyathit among the species of Danio evaluated in this analysis. Microrasbora and Rasbora are non‐monophyletic assemblages; however, Boraras is monophyletic. J. Exp. Zool. (Mol. Dev. Evol.) 308B:642–654, 2007. © 2007 Wiley‐Liss, Inc.
Temporal and spatial profiles of cell loss after spinal cord injury: Reduction by a metalloporphyrin
Authors: Ling Xiang , Liu Danxia 
Published: June 2007

AbstractThis study presents quantitative temporal and spatial profiles of neuronal loss and apoptosis following a contusion spinal cord injury (50 g · cm). The profiles were evaluated by counting the cresol violet–stained surviving cells and the total number of TUNEL‐positive cells and of TUNEL‐positive neurons in sections 0– 4 mm from the epicenter and 1, 6, 12, 24, 48, and 72 hr and 1 week postinjury. We demonstrated that neurons continue to disappear over 1 week postinjury and that neuronal loss shifts to areas longer distances from the epicenter over time. TUNEL‐positive cells in both gray and white matter appeared after 6 hr, gradually increased to a peak level after 48 hr, and declined by 72 hr postinjury. TUNEL‐positive neurons peaked earlier and were present for 1 week, although the total number of neurons was reduced significantly by the end of the week. The neuronal loss and apoptosis were partially prevented by a metalloporphyrin [Mn(III) tetrakis (4‐benzoic acid) porphyrin (MnTBAP)]. We demonstrated that MnTBAP (10 and 50 mg/kg, given intraperitoneally) significantly reduced neuronal death in the sections 1–2.5 mm rostral and 1 mm caudal from the epicenter compared with that in the vehicle‐treated group, suggesting MnTBAP is more effective in the sections rostral than in those caudal to the epicenter. MnTBAP (10 mg/kg) significantly reduced the number of TUNEL‐positive neurons in the sections 1 mm caudal from the epicenter. Our profiles provide a database for pharmacological intervention, and our results on MnTBAP treatment support an important role for antioxidant therapy in spinal cord injury. © 2007 Wiley‐Liss, Inc.
Signaling through C5aR is not involved in basal neurogenesis
Authors: Bogestål Yalda Rahpeymai , Barnum Scott R. , Smith Peter L.P. , Mattisson Victor , Pekny Milos , Pekna Marcela 
Published: June 2007

AbstractThe complement system, an important part of the innate immune system, provides protection against invading pathogens, in part through its proinflammatory activities. Although most complement proteins are synthesized locally in the brain and the relevant complement receptors are expressed on resident brain cells, little is known about brain‐specific role(s) of the complement system. C3a and C5a, complement‐derived peptides with anaphylatoxic properties, have been implicated in noninflammatory functions, such as tissue regeneration and neuroprotection. Recently, we have shown that signaling through C3a receptor (C3aR) is involved in the regulation of neurogenesis. In the present study, we assessed basal neurogenesis in mice lacking C5a receptor (C5aR–/–) and mice expressing C3a and C5a, respectively in the CNS under the control of glial fibrillary acidic protein (GFAP) promoter (C3a/GFAP and C5a/GFAP, respectively) and thus without the requirement for complement activation. We did not observe any difference among C5aR–/–, C3a/GFAP and C5a/GFAP mice and their respective controls in the number of newly formed neuroblasts and newly formed neurons in the subventricular zone (SVZ) of lateral ventricles and hippocampal dentate gyrus, the two neurogenic niches in the adult brain, or the olfactory bulb, the final destination of new neurons formed in the SVZ. Our results indicate that signaling through C5aR is not involved in basal neurogenesis in adult mice and that basal neurogenesis in adult C3a/GFAP and C5a/GFAP mice is not altered. © 2007 Wiley‐Liss, Inc.