bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved bounds for sampling contingency tables
Authors: Morris Ben J. 
Published: October 2002

AbstractWe study the problem of sampling contingency tables (nonnegative integer matrices with specified row and column sums) uniformly at random. We give an algorithm which runs in polynomial time provided that the row sums ri and the column sums cj satisfy ri = Ω(n3/2m log m), and cj = Ω(m3/2n log n). This algorithm is based on a reduction to continuous sampling from a convex set. The same approach was taken by Dyer, Kannan, and Mount in previous work. However, the algorithm we present is simpler and has weaker requirements on the row and column sums. © 2002 Wiley Periodicals, Inc. Random Struct. Alg., 21: 135–146, 2002
Use of differential charging to analyse microscopic specimens of Azolla leaves by XPS
Authors: Genet Michel J. , Jacques Christine , Mozes Nava , Hove Charles Van , Lejeune André , Rouxhet Paul G. 
Published: October 2002

AbstractCavity cuticles that surround the bacterial symbionts residing in the leaf cavities of the aquatic fern Azolla and Azolla leaf cuticle on the epidermis outside the cavity (outer cuticle) were submitted to XPS analysis. Differential charging enabled the signals of the microscopic sample and the support signals to be differentiated. The cavity cuticle has a composition similar to cutin. In comparison with the outer cuticle, it is characterized by a lower concentration of aliphatic chains and a higher concentration of oxygen‐containing functions. This has implications in term of solute transport between the leaf and the bacteria. Copyright © 2002 John Wiley & Sons, Ltd.
Sample size and power determination for clustered repeated measurements
Authors: Liu Aiyi , Shih W. J. , Gehan E. 
Published: October 2002

AbstractIt is common in epidemiological and clinical studies that each subject has repeated measurements on a single common variable, while the subjects are also ‘clustered’. To compute sample size or power of a test, we have to consider two types of correlation: correlation among repeated measurements within the same subject, and correlation among subjects in the same cluster. We develop, based on generalized estimating equations, procedures for computing sample size and power with clustered repeated measurements. Explicit formulae are derived for comparing two means, two slopes and two proportions, under several simple correlation structures. Copyright © 2002 John Wiley & Sons, Ltd. abstract
Perspectives on differences in perceived external stress: a study of women and men with coronary heart disease
Authors: Hallman Tina , Perski Aleksander , Burell Gunilla , Lisspers Jan , Setterlind Sven 
Published: October 2002

AbstractFocuses on diversities among women and men are rare, and few studies have focused on gender differences in psychosocial factors and coronary heart disease. The present study is one of a series in which a wide range of psychosocial factors will be analysed with a focus on women. We compared women with men as regards the impact of educational level and occupational position on differences in perceived external stress. A questionnaire (The Stress Profile) was answered by 538 rehabilitation participants (97 women, 441 men), and a reference group (5308 women, 5177 men), aged 40–65 years. Generally, women reported a higher value of perceived external stress than men. Most interesting, however, are the patterns of differences that emerged when women and men were compared in different subgroups. Women with upper secondary school education and women in white‐collar positions reported significantly higher levels of perceived external stress than men in the respective groups. When using common multivariate methods and adjusting for gender a great deal of information can be lost, and adjusting for gender makes it more difficult to find the true effect of exposures. It is only by regarding women and men separately that it is possible to link their very different working conditions and experience of stress to different health effects and vice versa. Copyright © 2002 John Wiley & Sons, Ltd.
Assessment of subjective stress in the municipal police force of the city of Rome
Authors: Pancheri P. , Martini A. , Tarsitani L. , Rosati M. V. , Biondi M. , Tomei F. 
Published: October 2002

AbstractThe aim of the study was to perform a dimensional assessment of subjective stress in the Municipal Police of the City of Rome. We assessed two random samples of 590 traffic police and 590 clerical police officers of both sexes for subjective stress through the administration of the ‘Rapid Stress‐Assessment Scale’ (RSA), a self‐rated tool; subjects completed the questionnaire during a non‐working day. Subsequently, from each sample we randomly included two subsamples of 115 subjects each, to whom we administered the RSA at the beginning and at the end of their shift. Significant differences between traffic and clerical police officers were found in the RSA total score, which was higher among traffic agents. Traffic police officers were found significantly more often in the ‘high stress class’. Gender differences analysis showed higher scores among women. The analysis of the subsample of 230 persons showed a significantly greater degree of the RSA ‘depression’ cluster at the end of the shift only in traffic police officers. The assessment of over‐the‐counter drug use (NSAID, analgesics, etc.) showed that, among police officers habitually using such drugs, only the traffic police subgroup scored higher on the RSA. Our results could be taken to mean that the stress response of Municipal Police officers who work outdoors is more maladaptive than that of officers working in the office; this could be compatible with the existence of different occupational stressors between the two groups. Copyright © 2002 John Wiley & Sons, Ltd.
An evolutionary perspective on strategic group emergence: a genetic algorithm‐based model
Authors: Lee Jeho , Lee Kyungmook , Rho Sangkyu 
Published: October 2002

AbstractWe develop a simulation model to examine conditions under which strategic groups emerge and their performance difference persists. In our model, mobility barriers, strategic interactions among high performers, dynamic capabilities (the mechanisms that allow winners to continue to survive), and boundary of rivalry are put together to derive their joint implications for the evolution of strategic groups. Not surprisingly, our model behavior shows that mobility barriers and strategic interactions play an important role in sustaining intergroup performance difference. However, the extremely high level of mobility barriers is shown to impede the emergence of strategic groups. We also find that dynamic capabilities and boundary of rivalry are as essential as mobility barriers in understanding the emergence and stability of strategic groups. When dynamic capabilities are absent or when rivalry is extended over firms with dissimilar strategies, strategic groups are less likely to exist. These findings can serve as a guideline for empirical research to probe why strategic groups exist sometimes and why they do not at other times. Copyright © 2002 John Wiley & Sons, Ltd.
Bytecode verification on Java smart cards
Authors: Leroy Xavier 
Published: October 2002

AbstractThis article presents a novel approach to the problem of bytecode verification for Java Card applets. By relying on prior off‐card bytecode transformations, we simplify the bytecode verifier and reduce its memory requirements to the point where it can be embedded on a smart card, thus increasing significantly the security of post‐issuance downloading of applets on Java Cards. This article describes the on‐card verification algorithm and the off‐card code transformations, and evaluates experimentally their impact on applet code size. Copyright © 2002 John Wiley & Sons, Ltd.
Extending North Atlantic oscillation reconstructions back to 1500
Authors: Luterbacher J. , Xoplaki E. , Dietrich D. , Jones P. D. , Davies T. D. , Portis D. , Gonzalez‐Rouco J. F. , von Storch H. , Gyalistras D. , Casty C. , Wanner H. 
Published: October 2002

AbstractMonthly (1659–1995) and seasonal (1500–1658) North Atlantic Oscillation (NAO) indices were estimated using instrumental and documentary proxy predictors from Eurasia. Uncertainty estimates were calculated for the reconstructions, and the variability of the 500‐year winter NAO has been assessed. The late twentieth century NAO extremes are within the range of variability during earlier centuries. Copyright © 2003 Royal Meteorological Society.
Analysis of spindle microtubule organization in untreated and taxol‐treated PtK1 cells.
Authors: Snyder Judith A. , Mullins J. Michael 
Published: October 2002

AbstractTaxol, a microtubule stabilizing agent, has been used to study changes in spindle microtubule organization during mitosis. PtK1 cells have been treated with 5 μg/ml taxol for brief periods to determine its effect on spindle architecture. During prophase taxol induces microtubules to aggregate, particularly evident in the region between the nucleus and cell periphery. Taxol induces astral microtubule formation in prometaphase and metaphase cells concomitant with a reduction in spindle length. At anaphase taxol induces an increase in length in astral microtubules and reduces microtubule length in the interzone. Taxol‐treated telophase cells show a reduction in the rate of furrowing and astral microtubules lack a discrete focus and are arranged more diffusely on the surface of the nuclear envelope. In summary, taxol treatment of cells prior to anaphase produces an increase in astral microtubules, a reduction in kinetochore microtubules and a decrease in spindle length. Brief taxol treatments during anaphase through early G1 promotes stabilization of microtubules, an increase in the length of astral microtubules and a delayed rate of cytokinesis.
Bovine lactoferrin in involuting mammary tissue
Authors: Hurley W. L. , Rejman J. J. 
Published: October 2002

AbstractBovine lactoferrin in involuting mammary tissue was identified by immunohistochemistry and tissue explant culture. Immunoreactive lactoferrin was associated with mammary epithelial cells. Immunostaining for lactoferrin increased during involution, in contrast to declining immunostaining of epithelia for the milk‐specific protein β‐lactoglobulin. Immunostaining for lactoferrin also was observed at the basal region of alveolar epithelia, perhaps in association with basement membrane components. Lactoferrin was preferentially synthesized in involuting mammary tissue compared with lactating tissue. Synthesis of lactoferrin in the involuting mammary gland occurs despite the apparent decline in synthesis of milk‐specific proteins.
Acid phosphatase activity in the larval salivary glands of developing Drosophila melanogaster.
Authors: Jones Helen E. , Bowen Ivor D. 
Published: October 2002

AbstractBoth the biochemical profile and the optical and fine structural localization of acid phosphatase activity in the larval salivary glands of developing Drosophila melanogaster is described. Biochemically, acid phosphatase shows peak activity in the glands of feeding larvae, followed by a marked decline. Directly preceding the onset of cell histolysis however, enzyme activity increases 1.5 fold and is maintained at this level. Histochemically, acid phosphatase activity initially appears as discrete point or lysosomal sources. As development proceeds, an intense and diffuse form of enzyme is seen, accompanying an extremely vacuolated cytoplasm. Ultrastructurally, the enzyme is located in lysosomes, Golgi elements, multivesicular bodies and both within, and on the extracisternal surface of the rough endoplasmic reticulum. This extracisternal or cytosolic form appears directly preceding cell lysis and eventually shows a comprehensive cellular distribution. Large numbers of acid phosphatase positive haemocytes are attached to the basal glandular surface at all developmental stages. In morphologically intact gland cells, discrete extracisternal enzyme activity appears associated with local areas of degradation.
Cell surface binding of colloidal iron and Limax flavus agglutinin compared by X‐ray microanalysis.
Authors: Thomas N. , Evans P. M. , Gwynn Ap I. 
Published: October 2002

AbstractThe surface characteristics of tumour cells and T‐cell hybridoma variants were examined by quantitative X‐ray microanalysis using metal‐based probes. Comparisons of populations of cells differing in invasive potential revealed differences in the binding of positive colloidal iron hydroxide, a general probe for anionic sites. Substantial differences between populations were also detected by the binding of Limax flavus agglutinin, which was used in conjunction with fetuin‐gold as a specific marker for sialic acid.
Production of the metastatic phenotype by DNA transfection in a rat mammary model.
Authors: Davies Barry R. , Barraclough Roger , Davies Michael P. A. , Rudland Philip S. 
Published: October 2002

AbstractA syngeneic, immunocompetent rat mammary model has been employed to investigate the molecular basis of the metastatic phenotype. Transfection of the benign rat mammary epithelial cell line Rama 37 with the gene for p9Ka; a small, rat, calcium‐binding protein or DNA from metastatic human cell lines derived from a primary breast carcinoma or a pleural effusion yields transfectants with metastatic capabilities. Transfection of DNA from a benign human mammary cell line, a plasmid containing a cDNA for the human basic fibroblast growth factor (bFGF) gene, or the oncogene EJ‐ras‐1, fails to yield any transfectants expressing the metastatic phenotype.
Metal‐binding proteins in eggs of various sea urchin species.
Authors: Scudiero R. , Capasso C. , De Prisco P. P. , Capasso A. , Filosa S. , Parisi E. 
Published: October 2002

AbstractMetallothionein presence and amount were determined in the unfertilized eggs of six sea urchin species by silver saturation assay and gel‐chromatography of cell extracts. The results showed high levels of metallothionein in the egg cytoplasm of the two Mediterranean species Paracentrotus lividus and Sphaerechinus granularis. No metallothionein was found either in the eggs of Arbacia lixula, or in those of the three Eastern species Strongylocentrotus intermedius, Temnopleurus hardwickii and Clypeaster japonicus. However, the extracts of the latter three species revealed the presence of zinc bound in a macromolecular form, thus suggesting the existence of metal‐binding proteins distinct from metallothioneins.
Dystrophin does not influence regular cytoskeletal architecture but is required for contractile performance in smooth muscle aortic cells.
Authors: Harricane Marie‐Cécile , Febris Eric , Lees Delphine , Prades Catherine , Travo Pierre , Mornet Dominique 
Published: October 2002

ABSTRACTCultured vascular smooth muscle cells express distinct histological phenotypes due to a contractile to synthetic stage transition. In this study, we compared the behaviour of cultured aortic smooth muscle cells from young normal and mdx mice. Morphological, immunobiochemical, immunocytochemical analyses and contraction studies of these cells demonstrated that (i) the cell cytoskeleton in mdx mice is not affected by the absence of dystrophin since proteins such as caldesmon, a‐actin, and vinculin are expressed similarly in normal mice, (ii) utrophin (or dystrophin‐related protein) overexpression does not compensate for the physiological and functional role of the lacking dystrophin. These data suggested that dystrophin and utrophin cannot substitute one another and may play different or complementary roles within smooth muscle cells.
Proliferation of human leukemic pre‐B cells induced by human bone marrow stromal cells and murine fibroblasts.
Authors: Buske Christian , Hiddemann Wolfgang , Wörmann Bernhard 
Published: October 2002

ABSTRACTAim of the study was the establishment of a standardized in vitro culture system for studies on proliferation and differentiation of human leukemic pre ‐ B cells. Coincubation with human stromal cells led to a significantly higher proliferation of the cytokine ‐ sensitive leukemic pre ‐ B cell line BLIN‐1. Clones from the murine fibroblast cell line L929 provided identical results. Coincubation with the murine cells also resulted in a significantly higher numbers of viable cells in 5 of 8 patient samples with newly diagnosed B lineage ALL. The results show that in vitro bone marrow stromal cells can be substituted by murine fibroblasts and form the basis for a simpler and more reproducible assay system.
On interleukins 4, 6 and 10 and their interrelationship with immunoglobulins G and M in common variable immunodeficiency.
Authors: Fritsch A. , Junker U. , Vogelsang H. , Jager L. 
Published: October 2002

ABSTRACTFollowing culture of human peripheral blood mononuclear cells (PBMNC) from 25 normal donors and 15 patients with common variable immunodeficiencv (CVID), we were unable to identify any IL10‐defective patients. Clear‐cut effects of IL4 could be demonstrated in controls, while in CVID all effects are less pronounced. While in both controls and CVID baseline levels of 1L6, IgG and IgM were found to be correlated, this was altered by the addition of either IL4 or Poke Weed Mitogen (PWM). We therefore conclude that the inability of PBMNC to produce IL10 is not the cause of CVID in our patients. In CVID, the regulating circuitry triggered by IL4 remains principally intact, however, some subgroups of CVID behave significantly differently.
Secretory proteins and growth factors of the baboon (Papio anubis) uterus: potential roles in pregnancy.
Authors: Fazleabas Asgerally T. , Hild‐Petito Sheri , Verhage Harold G. 
Published: October 2002

SummaryThe primate endometrium undergoes distinct morphological changes during the menstrual cycle. These alterations are regulated by the steroid hormones, estrogen and progesterone. Several lines of evidence suggest that some of these hormonally induced changes may be modulated by growth factors. Our studies have focused on characterizing the secretory activity of the uterine endometrium associated with these hormonally regulated morphological changes during the menstrual cycle and pregnancy in the baboon. Additionally, we have also attempted to study the regulation of specific growth factors and their receptors. In this review we present evidence to indicate that growth factor receptors for insulin‐like growth factor‐I (IGF‐I) and epidermal growth factor (EGF), and secretory proteins, insulin‐like growth factor binding protein‐1 (IGFBP‐1) and retinol binding protein (RBP), which are present in the glandular epithelium during the menstrual cycle, undergo cell‐specific changes in gene expression at the implantation site during pregnancy. We postulate that these alterations in growth factor receptor and secretory protein expression are conceptus modulated and may play important regulatory roles during trophoblast invasion and decidualization.
Insulin treatment (hormonal imprinting) increases the insulin production of the unicellular Tetrahymena long term. Is there a simultaneous formation of hormone receptor and hormone?
Authors: Csaba G. , Kovács P. 
Published: October 2002

AbstractInsulin treatment of Tetrahymena pyriformis resulted in a long‐lasting increase in the insulin content of the cells. After about 200 generations, insulin levels significantly higher than in the control were demonstrated by using a quantitative immunocytochemical method. Although the insulin content fluctuated from day to day, it was always higher in the insulin pre‐treated (imprinted) cells than in the controls. The results emphasise the simultaneous stimulation of hormone and receptor formation by hormonal imprinting.
Keratinocyte growth factor
Authors: Rubin Jeffrey S. , Bottaro Donald P. , Chedid Marcio , Miki Toru , Ron Dina , Cheon Hyae‐Gyeong , Taylor William G. , Fortney Emma , Sakata Hiromi , Finch Paul W. , LaRochelle William J. 
Published: October 2002

ABSTRACTKeratinocyte growth factor (KGF) is a member of the heparin‐binding fibroblast growth factor family (FGF‐7) with a distinctive pattern of target‐cell specificity. Studies performed in cell culture suggested that KGF was mitogenically active only on epithelial cells, albeit from a variety of tissues. In contrast, KGF was produced solely by cells of mesenchymal origin, leading to the hypothesis that it might function as a paracrine mediator of mesenchymal‐epithelial communication. Biochemical analysis and molecular cloning established that the KGF receptor (KGFR) was a tyrosine kinase isoform encoded by the fgfr‐2 gene. Many detailed investigations of KGF and KGFR expression in whole tissue and cell lines largely substantiated the pattern initially perceived in vitro of mesenchymal and epithelial distribution, respectively. Moreover, functional assays in organ culture and in vivo and studies of KGF regulation by sex sterorid hormones reinforced the idea that KGF acts predominantly on epithelial cells to elicit a variety of responses including proliferation, migration and morphogenesis.
Activation of macrophage‐like cells by multiple grooved substrata. Topographical control of cell behaviour.
Authors: Wójciak‐Stothard Beata , Madeja Zbigniew , Korohoda Wlodzimierz , Curtis Adam , Wilkinson Christopher 
Published: October 2002

AbstractWe studied the influence of substrata topography on the behaviour of murine P388D1 macrophage cell line. Cells were plated on plain fused silica substrata or substrata with microfabricated grooves of varying depth and width. Cell spread area, elongation, orientation and F‐actin content were measured on plain substratum and 6 sets of gratings. The speed and persistence of cell movement were also studied.We found that patterned substrata substantially activated cell spreading and elongation and significantly increased the persistence and speed of cell movement, shallow grooves being more effective than deep ones. The contact of cells with micropatterned substrata significantly increased the F‐actin content in cells. The sensitivity of LPS (lipopolisaccharide) stimulated and unstimulated macrophages to topographical cues was also compared.
Germ line chimera produced by transfer of cultured chick primordial germ cells.
Authors: Chang Il‐Kuk , Yoshiki Atsushi , Kusakabe Moriaki , Tajima Atsushi , Chikamune Tateki , Naito Mitsuru , Ohno Tadao 
Published: October 2002

AbstractIntrinsic primordial germ cells (PGCs) from stage 27 (5‐day‐old) chick embryonic germinal ridges were cultured in vitro for a further 5 days, and shown to proliferate on stroma cells derived from the germinal ridge. To determine whether these cultured PGCs could colonize and contribute to the germ‐line, PGCs were isolated by gentle pipetting, labeled with PKH26 fluorescent dye and injected into the blood stream of stage 17 (2.5‐day‐old) chick embryos. The recipient embryos were incubated until they reached stage 28. Thin sections of these embryos were analysed by fluorescent confocal laser microscopy. These analyses showed that the labeled donor PGCs had migrated into the germinal ridges of the recipient embryos, and transplanted PGCs had undergone at least 3‐7 divisions. These results suggest that PGCs that had passed far beyond the migration stage in vivo were still able to migrate, colonize and proliferate in recipient chick embryonic gonads.