bluuebunny/crossref_metadata_2025_split huggingface dataset:
Embedded turbulence model in numerical methods for hyperbolic conservation laws
Authors: Drikakis D. 
Published: September 2002

AbstractThe paper describes the use of numerical methods for hyperbolic conservation laws as an embedded turbulence modelling approach. Different Godunov‐type schemes are utilized in computations of Burgers' turbulence and a two‐dimensional mixing layer. The schemes include a total variation diminishing, characteristic‐based scheme which is developed in this paper using the flux limiter approach. The embedded turbulence modelling property of the above methods is demonstrated through coarsely resolved large eddy simulations with and without subgrid scale models. Copyright © 2002 John Wiley & Sons, Ltd.
Guaranteed‐content prediction intervals for non‐linear autoregressions
Authors: Luna Xavier de 
Published: September 2002

AbstractIn this paper we present guaranteed‐content prediction intervals for time series data. These intervals are such that their content (or coverage) is guaranteed with a given high probability. They are thus more relevant for the observed time series at hand than classical prediction intervals, whose content is guaranteed merely on average over hypothetical repetitions of the prediction process. This type of prediction inference has, however, been ignored in the time series context because of a lack of results. This gap is filled by deriving asymptotic results for a general family of autoregressive models, thereby extending existing results in non‐linear regression. The actual construction of guaranteed‐content prediction intervals directly follows from this theory. Simulated and real data are used to illustrate the practical difference between classical and guaranteed‐content prediction intervals for ARCH models. Copyright © 2001 John Wiley & Sons, Ltd.
Karyotypic similarity identified by multiplex‐FISH relates four prostate adenocarcinoma cell lines: PC‐3, PPC‐1, ALVA‐31, and ALVA‐41
Authors: Varella‐Garcia Marileila , Boomer Theresa , Miller Gary J. 
Published: September 2002

AbstractRecently developed molecular cytogenetic techniques for karyotyping are providing new and important insights regarding the chromosomal changes that occur in solid tumors. We used multiplex‐FISH to analyze four adenocarcinoma cell lines, PC‐3, PPC‐1, ALVA‐31, and ALVA‐41, in which the characterization of a large number of rearranged chromosomes was partially or substantially inconclusive by G‐banding. Although the original descriptions of these lines depict them as distinct entities established from different patients, this study demonstrates that these four lines share numerous, highly rearranged chromosomes, strongly supporting the conclusion that they are derived from the same patient material. Our analysis indicates that PPC‐1, ALVA‐31, and ALVA‐41 were derived from PC‐3 through mechanisms involving clonal progression represented by sequential changes and clonal diversion represented by differing patterns of changes. Extensive cellular heterogeneity was detected in all four lines, and most rearrangements included segments derived from multiple chromosomes. Each line also showed a set of unique derivative chromosomes. However, a limited number of metaphase cells (approximately 10) was analyzed for each line, and numerous single‐cell abnormalities were detected in all of them. Therefore, it is plausible that the number of clonal, shared, and/or unique rearrangements has been underestimated. These cell lines have been utilized as models for understanding the biology of prostate cancer and reportedly differ in their cell physiology. Rather than detracting from their value, a complete understanding of the interrelationships of these lines to one another may provide the opportunity to define the molecular changes that have led to their individual malignant phenotypes. © 2001 Wiley‐Liss, Inc.
Amplification of Mycn, Ddx1, Rrm2, and Odc1 in rat uterine endometrial carcinomas
Authors: Karlsson Åsa , Helou Khalil , Walentinsson Anna , Hedrich Hans J. , Szpirer Claude , Levan Göran 
Published: September 2002

AbstractThe BDII rat is genetically predisposed to estrogen‐dependent endometrial adenocarcinoma and represents a valuable model for this type of tumor. Tumors arising in strain crosses involving the BDII rats had previously been screened for DNA copy number changes using comparative genome hybridization (CGH). It was found that extra copies of the proximal region of rat chromosome (RNO) 6 commonly could be detected in these tumors. Based on RH‐mapping data and comparative mapping with mouse and human, seven cancer‐related genes were predicted to be situated in RNO6q14–q16. Rat PACs were isolated for the N‐myc proto‐oncogene (Mycn), apolipoprotein B (Apob), the DEAD box gene 1 (Ddx1), ornithine decarboxylase 1 (Odc1), proopiomelanocortin (Pomc1), ribonucleotide reductase, M2 polypeptide (Rrm2), and syndecan 1 (Sdc1). The localization of the genes to the region was verified by FISH (fluorescence in situ hybridization) mapping, and the detailed order among them was determined by dual‐color FISH. By Southern blot analysis, it was found that the Mycn locus was highly amplified in two out of 10 cell cultures derived from the tumors. In one of them (designated RUT30), the amplification level of Mycn was estimated at 140×. Two other genes were coamplified (Ddx1 and Rrm2) at much lower levels. Similarly, in another culture (designated RUT2), Mycn was amplified more than 40×, whereas three of the other genes (Ddx1, Rrm2, and Odc1) were coamplified at lower levels. Using FISH on metaphase chromosomes from the cell cultures analyzed, the amplified sequences were shown to be located in typical HSRs. With competitive RT‐PCR, distinct overexpression of Mycn and Ddx1 could be demonstrated in both RUT2 and RUT30. In addition, Mycn was overexpressed in two other tumors not exhibiting Mycn amplification. Taken together, our results suggest that overexpression of Mycn plays an important role in the development of endometrial cancer in the BDII rat. In humans, Mycn amplification has been reported mainly from tumors of neuronal origin. To our knowledge, this is the first report of Mycn amplification and overexpression in hormone‐dependent tumors. © 2001 Wiley‐Liss, Inc.
Methylation pattern of different regions of the MLH1 promoter and silencing of gene expression in hereditary and sporadic colorectal cancer
Authors: Menigatti Mirco , Di Gregorio Carmela , Borghi Francesca , Sala Elisa , Scarselli Alessandra , Pedroni Monica , Foroni Moira , Benatti Piero , Roncucci Luca , Ponz de Leon Maurizio , Percesepe Antonio 
Published: September 2002

AbstractNonrandom, widespread promoter methylation of tumor suppressor genes is a common mechanism of gene inactivation during tumorigenesis. We examined the methylation status of two distinct regions of the MLH1 promoter (proximal and distal to the transcription start site) and the MLH1 gene expression by methylation‐specific PCR and immunohistochemistry. A total of 72 colorectal tumors, both with (n = 51, 22 affected by hereditary nonpolyposis colorectal cancer, HNPCC, defined according to the international clinical criteria and 29 sporadic cases) and without microsatellite instability (MSI) (n = 21) were studied. Methylation was present in at least one of the two promoter regions in 86% of the sporadic MSI cases, in 33% of the cases lacking MSI, and in 23% of the HNPCC tumors. In the HNPCC cases with a known MLH1 mutation (n = 10) none of the two promoter regions was methylated. Hypermethylation in both MLH1 promoter regions was seen in 45% of the MSI sporadic cases vs. 5% of the MSI‐negative cases and 0% of the HNPCC cases. The overall concordance between the two promoter regions regarding methylation status was good (P = 0.009), but no significant correlation between methylation and suppression of the MLH1 immunohistochemical expression was found. Our data confirm that mutation and hypermethylation are mutually exclusive mechanisms in inducing mismatch repair deficiency and support the hypothesis of methylation as a process evenly distributed along the different regions of the promoter. © 2001 Wiley‐Liss, Inc.
Lithic raw material usages during the Middle Stone Age at Dakhleh Oasis, Egypt
Authors: Hawkins Alicia L. , Kleindienst Maxine R. 
Published: September 2002

AbstractDakhleh Oasis, the largest of the Egyptian Western Desert, presents an opportunity for diachronic study of lithic raw material preferences during the Middle Stone Age (MSA) of the Eastern Sahara. Archaeological aggregates and raw material sources are exposed and easily mapped. Diverse and abundant lithic raw materials derive from sandstone, shale, and limestone sources and are also found in secondary geological contexts. Three main raw materials were used, and there was strong preference for one of these: Tarawan chert. Easily available only in the north‐central oasis, this material was transported substantial distances even when other materials that were known and used by MSA peoples could be found closer at hand. There is little evidence for use of raw materials exogenous to Dakhleh Oasis. This pattern of usage does not appear to change from the older MSA units to the Aterian Dakhleh Unit. © 2002 Wiley Periodicals, Inc.
Early expression of glutamate transporter proteins in ramified microglia after controlled cortical impact injury in the rat
Authors: Van Landeghem Frank K.H. , Stover John F. , Bechmann Ingo , Brück Wolfgang , Unterberg Andreas , Bührer Christoph , Von Deimling Andreas 
Published: September 2002

AbstractTraumatic brain injury is followed by increased extracellular glutamate concentration. Uptake of glutamate is mainly mediated by the glial glutamate transporters GLAST and GLT‐1. Extent and distribution of GLAST and GLT‐1 were studied in a rat model of controlled cortical impact injury (CCII). Western Blot analysis revealed lowest levels of GLAST and GLT‐1 with a decrease by 40%–54% and 42%–49% between 24 and 72 h posttrauma. By 8 h after CCII, CSF glutamate levels were increased (10.5 μM vs. 2.56 μM in controls;P< 0.001), reaching maximum values by 48 h. A significant increase in de novo GLAST and GLT‐1 expressing ramified microglia was observed within 4 h, reached a stable level by 48 h, and remained high up to 72 h after CCII. Furthermore, ramified microglia de novo expressed the neuronal glutamate transporter EAAC1 after CCII. Following CCII, GLAST/GLT‐1 and GFAP coexpressing astrocytes were immediately reduced, reaching minimum levels within 8 h. This reduction of expression could be either due to protein downregulation or loss of astrocytes. At 72 h, a marked population of GLAST‐ and GLT‐1–positive reactive astrocytes appeared. These results support the hypothesis that reduced astrocytic GLAST and GLT‐1 protein levels following CCII contribute to evolving secondary injury. Microglia are capable of de novo expressing glutamate transporter proteins, indicating that the expression of glial and neuronal glutamate transporters is not restricted to a specific glial or neuronal lineage. Ramified microglia may play an important compensatory role in the early regulation of extracellular glutamate after CCII. GLIA 35:167–179, 2001. © 2001 Wiley‐Liss, Inc.
Effect of elevated K+, hypotonic stress, and cortical spreading depression on astrocyte swelling in GFAP‐deficient mice
Authors: Anděrová Miroslava , Kubinová Šárka , Mazel Tomáš , Chvátal Alexandr , Eliasson Camilla , Pekny Milos , Syková Eva 
Published: September 2002

AbstractGlial fibrillary acidic protein (GFAP) is the main component of intermediate filaments in astrocytes. To assess its function in astrocyte swelling, we compared astrocyte membrane properties and swelling in spinal cord slices of 8‐ to 10‐day‐old wild‐type control (GFAP+/+) and GFAP‐knockout (GFAP−/−) mice. Membrane currents and K+ accumulation around astrocytes after a depolarizing pulse were studied using the whole‐cell patch‐clamp technique. In vivo cell swelling was studied in the cortex during spreading depression (SD) in 3 to 6‐month‐old animals. Swelling‐induced changes of the extracellular space (ECS) diffusion parameters, i.e., volume fraction α and tortuosity λ, were studied by the real‐time iontophoretic tetramethylammonium (TMA+) method using TMA+‐selective microelectrodes. Morphological analysis using confocal microscopy and quantification of xy intensity profiles in a confocal plane revealed a lower density of processes in GFAP−/− astrocytes than in GFAP+/+ astrocytes. K+ accumulation evoked by membrane depolarization was lower in the vicinity of GFAP−/− astrocytes than GFAP+/+ astrocytes, suggesting the presence of a larger ECS around GFAP−/− astrocytes. Astrocyte swelling evoked by application of 50 mM K+ or by hypotonic solution (HS) produced a larger increase in [K+]e around GFAP+/+ astrocytes than around GFAP−/− astrocytes. No differences in α and λ in the spinal cord or cortex of GFAP+/+ and GFAP−/− mice were found; however, the application of either 50 mM K+ or HS in spinal cord, or SD in cortex, evoked a large decrease in α and an increase in λ in GFAP+/+ mice only. Slower swelling in GFAP−/− astrocytes indicates that GFAP and intermediate filaments play an important role in cell swelling during pathological states. GLIA 35:189–203, 2001. © 2001 Wiley‐Liss, Inc.
Electrophysiological alterations and upregulation of ATP receptors in retinal glial Müller cells from rats infected with the Borna disease virus
Authors: Pannicke Thomas , Weick Michael , Uckermann Ortrud , Wheeler‐Schilling Thomas , Fries Julia E. , Reichel Martin B. , Mohr Christopher , Stahl Tobias , Fluess Manuela , Kacza Johannes , Seeger Johannes , Richt Jürgen A. , Reichenbach Andreas 
Published: September 2002

AbstractInfection with the neurotropic Borna disease virus (BDV) causes an immune‐mediated neurological disease in a broad range of species. In addition to encephalitis, BDV‐infected Lewis rats develop a retinitis histologically characterized by the loss of most retinal neurons. By contrast, the dominating retinal macroglia, the Müller cells, do not degenerate. It is known from several models of neurodegeneration that glial cells may survive but undergo significant alterations of their physiological parameters. This prompted us to study the electrophysiology and ATP‐induced changes of intracellular Ca2+‐concentration ([Ca2+]i) in Müller cells from BDV‐infected rat retinae. Freshly isolated cells were used for whole‐cell patch‐clamp recordings. Whereas neither zero current potentials nor membrane resistances showed significant alterations, the membrane capacitance increased in cells from BDV‐infected rats during survival times of up to 8 months. This process was accompanied by a decrease in K+ current densities. Müller cells from BDV‐infected rats were characterized by expression of a prominent fast‐inactivating A‐type K+ current which was rarely found in control cells. Moreover, the number of cells displaying Na+ currents was slightly increased after BDV‐infection. ATP evoked increases in [Ca2+]i in Müller cells within retinal wholemounts of both control and BDV‐infected animals. However, the number of ATP‐responding isolated cells increased from 24% (age‐matched controls) to 78% (cells from animals ≥18 weeks after infection). We conclude that in BDV‐induced retinopathy, reactive rat Müller cells change their physiological parameters but these changes are different from those in Müller cells during proliferative vitreoretinopathy in man and rabbit. GLIA 35:213–223, 2001. © 2001 Wiley‐Liss, Inc.
Human MBP‐specific T cells regulate IL‐6 gene expression in astrocytes through cell–cell contacts and soluble factors
Authors: Colombatti Marco , Moretto Giuseppe , Tommasi Marina , Fiorini Emma , Poffe Ornella , Colombara Michaela , Tanel Raffaella , Tridente Giuseppe , Ramarli Dunia 
Published: September 2002

AbstractOne of the distinctive features of multiple sclerosis (MS) attacks is homing to the CNS of activated T cells able to orchestrate humoral and cell‐based events, resulting in immune‐mediated injury to myelin and oligodendrocytes. Of the complex interplay occurring between T cells and CNS constituents, we have examined some aspects of T‐cell interactions with astrocytes, the major components of the glial cells. Specifically, we focused on the ability of T cells to regulate the gene expression of interleukin‐6 (IL‐6) in astrocytes, based on previous evidence showing the involvement of this cytokine in CNS disorders. We found that T‐cell adhesion and T‐cell soluble factors induce IL‐6 gene expression in U251 astrocytes through distinct signaling pathways, respectively, resulting in the activation of NF‐κB and IRF‐1 transcription factors. In a search for effector molecules at the astrocyte surface, we found that α3β1 integrins play a role in NF‐κB activation induced by T‐cell contact, whereas interferon‐γ (IFN‐γ) receptors dominate in IRF‐1 induction brought about by T‐cell‐derived soluble factors. Similar phenomena were observed also in normal fetal astrocyte cultures. We therefore propose that through astrocyte induction, T cells may indirectly regulate the availability of a cytokine which is crucial in modulating fate and behavior of cell populations involved in the pathogenesis of MS inflammatory lesions. GLIA 35:224–233, 2001. © 2001 Wiley‐Liss, Inc.
Synthesis and reactions of conformational isomers of a stable selenenic acid bearing a bridged calix[6]arene framework
Authors: Goto Kei , Saiki Toshiyuki , Akine Shigehisa , Kawashima Takayuki , Okazaki Renji 
Published: September 2002

AbstractA stable selenenic acid bearing a bridged calix[6]arene framework fixed in the 1,2,3‐alternate conformation was synthesized. Its properties were compared with those of its conformational isomer fixed in the cone conformation, indicating that the reactivity of the endohedral SeOH group can be regulated by the conformation of the calix[6]arene framework. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:195–197, 2001
Thermodynamically stabilized chiral chalcogen oxides: optical resolution and stereochemistry
Authors: Taka Hideo , Matsumoto Akikuni , Shimizu Toshio , Kamigata Nobumasa 
Published: September 2002

AbstractOptical resolution of racemic selenoxides, 1a, 1b, and 1c, and telluroxide 2b, possessing an 8‐dimethylamino‐1‐naphthyl group by liquid chromatography using optically active columns afforded the corresponding enantiomerically pure stereoisomers. Absolute configurations of the optically active chalcogen oxides were assigned by comparison of their specific rotations and CD spectra with those of the sulfur analog. All of the optically active chalcogen oxides obtained were stable toward racemization in their solid states; however, selenoxides 1a and 1b and telluroxide 2b racemized in solutions. Kinetic studies of the racemization clarified that thermodynamic stabilization by intramolecular coordination of the nitrogen atom in the 8‐dimethylamino‐1‐naphthyl group to the chalcogen atom was effective to prevent the racemization. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:227–237, 2001
Acyl carbamoyl selenides and related sulfur isologues: synthesis and x‐ray structural analyses
Authors: Kageyama Hideki , Tani Kazuyasu , Kato Shinzi , Kanda Takahiro 
Published: September 2002

AbstractSelenocarboxylic acids [RC(=O)SeH] were found to readily react with aryl, acyl, and arenesulfonyl isocyanates to give the corresponding acyl carbamoyl selenides 3 [RC(=O)SeC(=O)NHR′, R′ = aryl, C6H5CO, and 4‐MeC6H4SO2] in good yields. Their tautomers [RC(=O)SeC(=NR′)OH] were also detected by 1H, 13C, and 77Se NMR spectroscopies. The structure of 3 [R = 2,6‐(MeO)2C6H3, R′ = 4‐MeC6H4] was characterized by X‐ray crystallography, which showed that this molecule is stabilized by an intramolecular hydrogen bond between the carbonyl oxygen and the NH hydrogen to form a planar six‐membered ring and by nonbonded interaction of the ortho methoxy oxygen with the carbonyl oxygen or the selenium atoms. 4‐Methoxybenzoyl and 4‐methoxythiobenzoyl N‐(4‐methylphenyl)carbamoyl sulfides (4 and 5) were shown by X‐ray crystallography to similarly have a planar intramolecular six‐membered ring formed by a hydrogen bond between the carbonyl oxygen or thiocarbonyl sulfur and NH hydrogen atoms. The tautomers [RC(=E)SC(=NR′)OH; E = O or S] of 4 and 5 also were detected spectroscopically. The reactions of 3h (R = 4‐MeOC6H4, R′ = Ph) with sodium methoxide and p‐toluidine gave sodium selenocarboxylate and the corresponding amides and urea as main products, respectively. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:250–258, 2001
Critical review of epidemiological studies of the association between smoking and non‐Hodgkin's lymphoma
Authors: Peach Hedley G. , Barnett Nicole E. 
Published: September 2002

AbstractSmoking has been suggested to increase the risk of non‐Hodgkin's lymphoma (NHL) but the results of epidemiological studies have been inconsistent. The aim of this work was to assess whether the findings of individual studies might have arisen by chance, bias or confounding and whether any associations found between smoking and NHL represent cause‐and‐effect. Reports of the association between smoking and NHL were identified from Medline. Confidence intervals on relative risks and odds ratios, use of multiple comparisons, and information on source, direction, actual existence and size of potential biases and confounding and features of any associations were abstracted. Four out of five cohort studies found no association between current smoking and NHL but three may have been biased against doing so. One found an association with follicular lymphoma but without a convincing exposure–risk gradient. The fifth found a strong association and an exposure–response gradient with ever smoking but excluded living cases from the end‐point. Only one study found an association with past smoking which lacked features of causality. Eight out of 14 case–control studies found no association between current and/or past smoking and NHL but five may have been biased against doing so. Of six positive studies, three involved multiple comparisons, the association of one became non‐significant after eliminating bias, four did not explore features of causality and one found an association only in heavy smokers, particularly under 45 years old. There are no grounds to reject the null hypothesis but associations should continue to be sought particularly in subgroups of smokers and with NHL subtypes. Copyright © 2001 John Wiley & Sons, Ltd.
Directional characteristics of radiation reflection on rough metal surfaces with description of heat transfer parameters
Authors: Makino Toshiro , Wakabayashi Hidenobu , Okada Shin‐ya 
Published: September 2002

AbstractIn this paper we clarify directional characteristics of thermal radiation reflection on rough metal surfaces and establish a technique for determining the parameters for heat transfer computation of radiation energy exchange among surfaces. Directional distribution of bidirectional reflectance ρ of surfaces of root‐mean‐square roughness Σ = 0.1 to 1 µm to the irradiation of a visible laser of wavelength λ = 0.6328 µm and to that of an infrared laser of λ = 3.39 µm is investigated experimentally. The optical roughness (Σ/λ) ranges from 0.028 to 1.27. A measure of the magnitude of specular reflection is presented. A model for describing the ρ distribution is presented, and the experimental results of the ρ distribution are analyzed quantitatively and systematically to determine the values of the specular reflection component Rs and the perfect‐diffuse reflection component Rd of the hemispherical reflectance RH, which are input parameters for radiation heat transfer computation. © 2002 Scripta Technica, Heat Trans Asian Res, 31(2): 76–88, 2002; DOI 10.1002/htj.10008