bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of in vivo lymphocyte proliferation between allogeneic and xenogeneic heart transplantation in mice
Authors: Kellersmann Richard , Kellersmann Anne , Thiede Arnulf , Ulrichs Karin 
Published: October 2003

AbstractThere are controversial in vitro data comparing the strength of the cellular immune response between allogeneic and xenogeneic stimulator/responder combinations. The present study therefore compares in vivo lymphocyte proliferation using heart transplantation (HTx) models in mice. Heterotopic HTx into BALB/c mice was performed using donor organs from mice (BALB/c and C57BL/6) or Lewis rats. Intraperitoneally given bromodeoxyuridine (BrdU) was incorporated into the DNA and was subsequently analyzed by flow cytometry. On postoperative days 3 and 5, proliferation of splenocytes, CD4+ T‐lymphocytes, and CD19+ B‐lymphocytes was significantly higher after xenogeneic than after allogeneic and isogeneic HTx. No significant difference was observed when proliferation of CD8+ lymphocytes was determined. The increased in vivo proliferation after xenotransplantation may reflect an earlier and probably stronger cellular immune response compared to allogeneic transplantation. The higher CD4+ lymphocyte proliferation underscores the importance of this cell population in xenograft rejection. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:498–502 2003
Optimization of a metastasizing human gastric cancer model in nude mice
Authors: Illert Bertram , Otto Christoph , Braendlein Stephanie , Thiede Arnulf , Timmermann Wolfgang 
Published: October 2003

AbstractOur purpose was to optimize the surgical orthotopic implantation (SOI) technique to create a reproducible gastric cancer model in nude mice with stable tumor growth and metastasizing course. We performed xenotransplantation of primary human tumor specimens from patients with gastric cancer (series 1) and orthotopic transplantation of tumor specimens originating from the gastric cancer cell line 23132/87 (series 2). All specimens were transplanted using microsurgical techniques. The two series were compared with regard to tumor growth rates and kinetics, development of metastases, and induction of minimal residual disease (MRD), as determined by histology and PCR techniques. In series 1 mice, the tumor growth rate was slow; in series 2 mice, it was both fast and reproducible. Unlike animals in series 1, animals in series 2 developed metastases and MRD. In conclusion, the optimized SOI technique presented here represents a reproducible and reliably metastasizing gastric cancer model. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:508–512 2003
Processable photonic polymers with controllable properties
Authors: Kallitsis J. K. , Andreopoulou A. K. 
Published: October 2003

AbstractA series of polyethers consisting of a conjugated segment connected with a nonconjugated spacer were synthesized and characterized. On the basis of the chemical structure of the conjugated moiety, controllable light emission was obtained. The thermal properties were influenced from the structure of the conjugated segment, the type of substituents used, and the length of the flexible spacer used. Additionally, coil‐rod‐coil block copolymers having conjugated segments as the rod block were prepared with atom transfer radical polymerization of α,ω‐modified conjugated oligomers. The optical properties of these copolymers were examined with respect to their aggregation behavior. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2485–2491, 2003
Negative differential mobility in pentacene
Authors: Conwell E. M. , Basko D. M. 
Published: October 2003

AbstractDespite narrow bands and large energy gaps, which result in a negligible number of intrinsic carriers, high‐quality molecular crystals, such as pentacene and naphthalene, show high mobilities at low temperatures. As a result, injected carriers can have their “temperature” increased by easily attainable electric fields. Their mobility is then expected to decrease with an increasing field, both because of the increased scattering rate and the increase in the effective mass due to the nonparabolicity of the energy bands. Using Poisson's equation, we investigate the effect on the current voltage characteristic of the mobility decrease being so steep over some field range that the drift velocity (vd) decreases with an increasing field; that is, the sample displays negative differential mobility (NDM) over that range. NDM is expected for samples in which the effective mass increases. We find that, with increasing voltage, V, after the Ohm's law region, there is a region in which J ∝ V2, as expected for a space‐charge‐limited value of J. When V is large enough to cause heating of the carriers, J increases less rapidly than V2, tending toward a linear dependence on V in the hot carrier region. Thus, V/J tends to saturate at high fields. It is shown that the data of Schön et al. for pentacene, when properly interpreted, show saturation of V/J rather than that of vd, as they claimed. The direct measurement of vd versus the field by the time‐of‐flight method for naphthalene at low temperatures by Warta and Karl was interpreted by them as indicating saturation of vd. We point out that the determination of vd by the time‐of‐flight method in a situation with varying mass and trapping is not straightforward. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2595–2600, 2003
Energy transfer and triplet exciton confinement in polymeric electrophosphorescent devices
Authors: Chen Fang‐Chung , Chang Shun‐Chi , He Gufeng , Pyo Seungmoon , Yang Yang , Kurotaki Masayuki , Kido Junji 
Published: October 2003

AbstractEnergy transfer and triplet exciton confinement in polymer/phosphorescent dopant systems have been investigated. Various combinations of host‐guest systems have been studied, consisting of two host polymers, poly(vinylcarbazole) (PVK) and poly[9,9‐bis(octyl)‐fluorene‐2,7‐diyl] (PF), blended with five different phosphorescent iridium complexes with different triplet energy levels. These combinations of hosts and dopants provide an ideal situation for studying the movement of triplet excitons between the host polymers and dopants. The excitons either can be confined at the dopant sites or can flow to the host polymers, subject to the relative position of the triplet energy levels of the material. For PF, because of its low triplet energy level, the exciton can flow back from the dopants to PF when the dopant has a higher triplet energy and subsequently quench the device efficiency. In contrast, efficient electrophosphorescence has been observed in doped PVK films because of the high triplet energy level of PVK. Better energy transfer from PVK to the dopants, as well as triplet exciton confinement on the dopants, leads to higher device performance than found in PF devices. Efficiencies as high as 16, 8.0, and 2.6 cd/A for green, yellow, and red emissions, respectively, can be achieved when PVK is selected as the host polymer. The results in this study show that the energy transfer and triplet exciton confinement have a pronounced influence on the device performance. In addition, this study also provides material design and selection rules for the efficient phosphorescent polymer light‐emitting diodes. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2681–2690, 2003
Thermoelectric power of sulphur at high pressure up to 40 GPa
Authors: Shchennikov Vladimir V. , Ovsyannikov Sergey V. 
Published: October 2003

AbstractFrom the thermoelectric power S measurements on sulphur at high pressure P, a hole‐type electrical conductivity has been established above 25 GPa. A correlation of the pressure dependence of S with the previously published optical reflectance data has been found. The positive value of S and its decrease with pressure have shown the similarity of the electron structure of sulphur and its neighbours from Group VI – Te and Se. However, a negative magnetoresistance (MR) established at P ≈ 30 GPa points to low mobility of holes and implies an indirect semiconductor gap for sulphur in contrast to the direct gap for Te and Se in the vicinity of the semiconductor–metal phase transition.
Modelling and simulation of multi‐phase effects on X‐ray elasticity constants
Authors: Fréour S. , Gloaguen D. , François M. , Guillén R. 
Published: October 2003

AbstractThis paper deals with the calculation of X‐ray Elasticity Constants (XEC) of phases embedded in multi‐phase polycrystals. A three scales (macroscopic, pseudo‐macroscopic, mesoscopic) model based on the classical self‐consistent formalism is developed in order to analyse multi‐phase effects on XEC values. Simulations are performed for cubic or hexagonal crystallographic structure phases embedded in several two‐phases materials. In fact, it is demonstrated that XEC vary with the macroscopic stiffness of the whole polycrystal. In consequence, the constants of one particular phase depend on the elastic behaviour and the volume fraction of all the phases constituting the material. Now, XEC play a leading role in pseudo‐macroscopic stresses determination by X‐Ray Diffraction (XRD) methods. In this work, a quantitative analysis of the multi‐phase effects on stresses determination by XRD methods was performed. Numerical results will be compared and discussed.
Electronic structure of CeBa2Cu3O7
Authors: Łuszczek M. , Laskowski R. 
Published: October 2003

AbstractThe linearized augmented plane wave (LAPW) method was used for spin‐polarized self‐consistent electronic structure calculations of CeBa2Cu3O7 (not synthesized as a single phase yet) and compared with three other members of the ReBa2Cu3O7 (denoted as Re123) family of compounds: Y123 (superconducting), Nd123 (superconducting) and Pr123 (potentially‐superconducting). The obtained band structures are qualitatively similar. We hypothesize that the spin‐split band structure observed in Pr123 and Ce123 could indicate the potential off‐stoichiometry, substitutional defects and as a consequence the suppression of superconductivity in the former, and the failure of single phase synthesis in the last system.
First‐principle simulations of the electronic structure of copper‐based oxide superconductors
Authors: Yutoh Y. , Sugihara S. 
Published: October 2003

AbstractThe relationship between the transition temperature (Tc) of an oxide superconductor and strain has been studied by means of experiments, with a focus an specimens that include an interface between a superconductor and a substrate. In the current study, we performed calculations on the bulk and the surface in order to investigate the electronic structures of the above systems. We calculated the electronic structure of La2CuO4 bulk by employment of three‐dimensional boundary conditions and that of a La2CuO4 surface by employment of two‐dimensional boundary conditions. The results for the bulk indicate that a relationship exists between the lattice parameters and Tc of La2CuO4. We discuss the calculated results for the bulk and surface on the basis of the results of investigation of the differences in electronic structures. The results indicate that the surface retained the electronic structures of the bulk.
ESD thresholds for KCl
Authors: Gołek F. 
Published: October 2003

AbstractElectron stimulated desorption (ESD) energy thresholds for thin KCl layers are measured relative to the target current onset. The applied procedure allow to correct electron beam energy for the contact potential difference in the system. The results show that the energy threshold for ESD of cations and anions (or neutral Cl) coincides with the fundamental absorption edge. The measured threshold energies are about 20 eV for Cl+ and about 8 eV for K+ and Cl (or Cl−) ESD. The 20 eV threshold for Cl+ signal confirms the involvement of an Auger transition in positive halogen ion emission while the 8 eV threshold for the other species is consistent with the so‐called “defect‐mediated desorption” model of ESD. It is proposed that the near surface lattice instability induced by electronic transition results in a local heating capable of ejecting constituent ion or neutral atom.
Origin of electron spin resonance in La0.7Ca0.3MnO3
Authors: Joh Keon Woo , Lee Chang Hoon , Lee Cheol Eui , Jeong Yoon Hee 
Published: October 2003

AbstractAn electron spin resonance study was carried out for a La0.7Ca0.3MnO3 bulk sample above the ferromagnetic ordering temperature. From careful analysis on the ESR parameters, it is shown that itinerant spins interacting with magnetic spin clusters in bottleneck regime are responsible for the ESR signals.
Ecological considerations support color physicalism
Authors: Clark James J. 
Published: October 2003

AbstractWe argue that any theory of color physicalism must include consideration of ecological interactions. Ecological and sensorimotor contingencies resulting from relative surface motion and observer motion give rise to measurable effects on the spectrum of light reflecting from surfaces. These contingencies define invariant manifolds in a sensory-spatial space, which is the physical underpinning of all subjective color experiences.
True color only exists in the eye of the observer
Authors: Cornelissen Frans W. , Brenner Eli , Smeets Jeroen 
Published: October 2003

AbstractThe colors we perceive are the outcome of an attempt to meaningfully order the spectral information from the environment. These colors are not the result of a straightforward mapping of a physical property to a sensation, but arise from an interaction between our environment and our visual system. Thus, although one may infer from a surface’ reflectance characteristics that it will be perceived as “colored,” true colors only arise by virtue of the interaction of the reflected light with the eye (and brain) of an observer.
Mechanisms of disrupted language comprehension in schizophrenia
Authors: Condray Ruth , Steinhauer Stuart R. 
Published: October 2003

AbstractMechanisms that contribute to perceptual processing dysfunction in schizophrenia were examined by Phillips & Silverstein, and formulated as involving disruptions in both local and higher-level coordination of signals. We agree that dysfunction in the coordination of cognitive functions (disconnection) is also indicated for many of the linguistic processing deficits documented for schizophrenia. We suggest, however, that it may be necessary to add a timing mechanism to the theoretical account.
Orange laser beams are not illusory: The need for a plurality of “real” color ontologies
Authors: Decock Lieven , van Brakel Jaap 
Published: October 2003

AbstractReflectance physicalism only provides a partial picture of the ontology of color. Byrne & Hilbert’ account is unsatisfactory because the replacement of reflectance functions by productance functions is ad hoc, unclear, and only leads to new problems. Furthermore, the effects of color contrast and differences in illumination are not really taken seriously: Too many “real” colors are tacitly dismissed as illusory, and this for arbitrary reasons. We claim that there cannot be an all-embracing ontology for color.
Productance physicalism and a posteriori necessity
Authors: Dedrick Don 
Published: October 2003

AbstractThe problem of nonreflectors perceived as colored is the central problem for Byrne & Hilbert's (B&H's) physicalism. Vision scientists and other interested parties need to consider the motivation for their account of “productance physicalism.” Is B&H's theory motivated by scientific concerns or by philosophical interests intended to preserve a physicalist account of color as a posteriori necessary?
Cognitive coordination deficits: A necessary but not sufficient factor in the development of schizophrenia
Authors: Gooding Diane C. , Braun Jacqueline G. 
Published: October 2003

AbstractThe Phillips & Silverstein model of NMDA-mediated coordination deficits provides a useful heuristic for the study of schizophrenic cognition. However, the model does not specifically account for the development of schizophrenia-spectrum disorders. The P&S model is compared to Meehl's seminal model of schizotaxia, schizotypy, and schizophrenia, as well as the model of schizophrenic cognitive dysfunction posited by McCarley and colleagues.
Parallels between hearing and seeing support physicalism
Authors: Handel Stephen , Erickson Molly L. 
Published: October 2003

AbstractThere are 2,000 hair cells in the cochlea, but only three cones in the retina. This disparity can be understood in terms of the differences between the physical characteristics of the auditory signal (discrete excitations and resonances requiring many narrowly tuned receptors) and those of the visual signal (smooth daylight excitations and reflectances requiring only a few broadly tuned receptors). We argue that this match supports the physicalism of color and timbre.
Theory of mind in schizophrenia: Damaged module or deficit in cognitive coordination?
Authors: Leiser David , Bonshtein Udi 
Published: October 2003

AbstractSchizophrenics exhibit a deficit in theory of mind (ToM), but an intact theory of biology (ToB). One explanation is that ToM relies on an independent module that is selectively damaged. Phillips & Silverstein's analyses suggest an alternative: ToM requires the type of coordination that is impaired in schizophrenia, whereas ToB is spared because this type of coordination is not involved.
Hue magnitudes and Revelation
Authors: Kulvicki John 
Published: October 2003

AbstractRevelation, the thesis that the full intrinsic nature of colors is revealed to us by color experiences, is false in Byrne & Hilbert's (B&H's) view, but in an interesting and nonobvious way. I show what would make Revelation true, given B&H's account of colors, and then show why that situation fails to obtain, and why that is interesting.
No blind schizophrenics: Are NMDA-receptor dynamics involved?
Authors: Sanders Glenn S. , Platek Steven M. , Gallup Gordon G. 
Published: October 2003

AbstractNumerous searches have failed to identify a single co-occurrence of total blindness and schizophrenia. Evidence that blindness causes loss of certain NMDA-receptor functions is balanced by reports of compensatory gains. Connections between visual and anterior cingulate NMDA-receptor systems may help to explain how blindness could protect against schizophrenia.
Spatial position and perceived color of objects
Authors: Nijhawan Romi 
Published: October 2003

AbstractVisual percepts are called veridical when a “real” object can be identified as their cause, and illusions otherwise. The perceived position and color of a flashed object may be called veridical or illusory depending on which viewpoint one adopts. Since “reality” is assumed to be fixed (independent of viewpoint) in the definition of veridicality (or illusion), this suggests that “perceived” position and color are not properties of “real” objects.
Reflectance-to-color mappings depend critically on spatial context
Authors: Rudd Michael E. 
Published: October 2003

AbstractIn visual science, color is usually regarded as a subjective phenomenon. The relationship between the specific color experiences that are evoked by a visual scene and the physical properties of the surfaces viewed in that scene are complex and highly dependent on spatial context. There is no simple correspondence between experienced color and a stable class of physical reflectances.
GCHap: fast MLEs for haplotype frequencies by gene counting
Authors: Thomas Alun 
Published: October 2003

Abstract
Summary: GCHap quickly finds maximum likelihood estimates (MLEs) of frequencies of haplotypes given genotype information on a random sample of individuals. It uses the gene counting method but by excluding haplotypes with zero MLE at an early stage, this implementation uses many orders of magnitude less space and time than naive implementations. A second program, ApproxGCHap, is provided to give alternate estimates for data sets with large numbers of loci or large amounts of missing genotypes.
Availability: The Java classes and Javadocs pages for GCHap can be obtained from bioinformatics.med.utah.edu/~alun
Intersect: identification and visualization of overlaps in database search results
Authors: Pegg Scott C.-H. , Novak Walter R. P. , Babbitt Patricia C. 
Published: October 2003

Abstract
Summary: The determination of distant evolutionary relationships remains an important biological problem, and distant homologs often appear in statistically insignificant regions of sequence similarity searches. Intersect is a computer program designed to identify and visualize the overlaps between sets of sequences reported by multiple database searches. This capability extends the usefulness of database search results and aids researchers in identifying the individual sequences that best bridge sequence families and superfamilies.
Availability: The Intersect program is available from the Babbitt laboratory website at http://www.babbittlab.ucsf.edu/software/intersect
Modes and clustering for time-warped gene expression profile data
Authors: Liu Xueli , Müller Hans-Georg 
Published: October 2003

Abstract
Motivation: The study of the dynamics of regulatory processes has led to increased interest for the analysis of temporal gene expression level data. To address the dynamics of regulation, expression data are collected repeatedly over time. It is difficult to statistically represent the resulting high-dimensional data. When regulatory processes determine gene expression, time-warping is likely to be present, i.e. the sample of gene expression trajectories reflects variation not only in terms of the expression amplitudes, but also in terms of the temporal structure of gene expression.
Results: A non-parametric time-synchronized iterative mean updating technique is proposed to find an overall representation that corresponds to a mode of a sample of expression profiles, viewed as a random sample in function space. The proposed algorithm explores the application of previous work of Hall and Heckman to genome-wide expression data and provides an extension that includes random time-warping with the aim to synchronize timescales across genes. The proposed algorithm is universally applicable for the construction of modes for functional data with time-warping. We demonstrate the construction of mode functions for a sample of Drosophila gene expression data. The algorithm can be applied to define clusters among the observed trajectories of gene expression, without any kind of prior non-time-warped clustering, as illustrated in the numerical example.
A computational pipeline for protein structure prediction and analysis at genome scale
Authors: Shah Manesh , Passovets Sergei , Kim Dongsup , Ellrott Kyle , Wang Li , Vokler Inna , LoCascio Philip , Xu Dong , Xu Ying 
Published: October 2003

Abstract
Motivation: Experimental techniques alone cannot keep up with the production rate of protein sequences, while computational techniques for protein structure predictions have matured to such a level to provide reliable structural characterization of proteins at large scale. Integration of multiple computational tools for protein structure prediction can complement experimental techniques.
Results: We present an automated pipeline for protein structure prediction. The centerpiece of the pipeline is our threading-based protein structure prediction system PROSPECT. The pipeline consists of a dozen tools for identification of protein domains and signal peptide, protein triage to determine the protein type (membrane or globular), protein fold recognition, generation of atomic structural models, prediction result validation, etc. Different processing and prediction branches are determined automatically by a prediction pipeline manager based on identified characteristics of the protein. The pipeline has been implemented to run in a heterogeneous computational environment as a client/server system with a web interface. Genome-scale applications on Caenorhabditis elegans, Pyrococcus furiosus and three cyanobacterial genomes are presented.
Availability: The pipeline is available at http://compbio.ornl.gov/proteinpipeline/