bluuebunny/crossref_metadata_2025_split huggingface dataset:
Penalized likelihood approach to estimate a smooth mean curve on longitudinal data
Authors: Jacqmin‐Gadda Hélène , Joly Pierre , Commenges Daniel , Binquet Christine , Chêne Geneviève 
Published: October 2002

AbstractThis paper aims to propose a penalized likelihood approach to estimate a smooth mean curve for the evolution with time of a Gaussian variable taking into account the correlation structure of longitudinal data. The model is an extension of the mixed effects linear model including an unspecified function of timef(t). The estimatorf̂(t) is defined as the solution of the maximization of the penalized likelihood and is approximated on a basis of cubic M‐spline with a reduced number of knots. We present modifications of four criteria (cross‐validation, generalized cross‐validation, T of Rice, Akaike's criterion) to estimate the smoothing parameter when data are correlated; these four criteria gave very similar results in the simulation study. The simulation study showed also the superiority of the Bayesian confidence bands of the mean curve over the frequentist ones. We develop empirical Bayes estimates of subject‐specific deviations. This approach was applied to study the progression of CD4+ lymphocyte counts in a cohort of HIV patients treated with protease inhibitors. Copyright © 2002 John Wiley & Sons, Ltd.
HARTEX—a safe real‐time kernel for distributed computer control systems
Authors: Angelov C. K. , Ivanov I. E. , Burns A. 
Published: October 2002

AbstractA hard real‐time kernel is presented for distributed computer control systems (DCCS), highlighting a number of novel features, such as integrated scheduling of hard and soft real‐time tasks as well as tasks and resources; high‐performance time management supporting safe DCCS operation in a hard real‐time environment; synchronization and communication featuring event notification via vector semaphores and transparent communication through implicit (content‐oriented) message addressing. Conventional queues have been substituted by Boolean vectors and vector processing techniques throughout the kernel, resulting in efficient and highly deterministic behaviour, which is characterized by very low overhead and constant execution time of kernel operations, independent of the number of tasks involved. Copyright © 2001 John Wiley & Sons, Ltd.
A security scheme for Aglets
Authors: Ono Kouichi , Tai Hideki 
Published: October 2002

AbstractAglets, a framework and runtime platform for mobile agents developed by the IBM Tokyo Research Laboratory, is an advanced system of mobile agents written in Java, and is already used in some commercial applications. Using mobile agent technologies provides potential benefits to applications, but they also pose security threats to those applications. These threats not only come as malicious agents, but also in the form of malicious hosts. In this paper we introduce security features against these threats. Access control and message protection can prevent attacks by malicious agents. Server authentication allows agents to avoid movement to malicious hosts and blocks suspicious agents coming from malicious hosts. Copyright © 2002 John Wiley & Sons, Ltd.
Eternal—a component‐based framework for transparent fault‐tolerant CORBA
Authors: Narasimhan P. , Moser L. E. , Melliar‐Smith P. M. 
Published: October 2002

AbstractEnterprises are increasingly involved in worldwide round‐the‐clock e‐commerce and e‐business, which requires them to be operational 24 hours per day, 7 days per week. With outages leading to loss of revenue, reputation and customers, fault tolerance becomes increasingly important. By mixing the fault tolerance logic into the application logic, existing fault tolerance practices render applications more complex, more prone to errors, and more difficult to maintain and build. The Eternal system is a component‐based middleware framework that provides transparent fault tolerance for enterprise applications, and that ensures continuous$24\times7$operation without requiring special skills of the application programmers. The Eternal system implements the new Fault‐Tolerant CORBA standard. Copyright © 2002 John Wiley & Sons, Ltd.
Spatial and temporal profile of haloperidol‐induced immediate‐early gene expression and phosphoCREB binding in the dorsal and ventral striatum of amphetamine‐sensitized rats
Authors: Hsieh Huei‐Ching , Li Hui‐Yun , Lin Ming‐Yu , Chiou Ya‐Fen , Lin Shao‐Yun , Wong Chung‐Hung , Chen Jin‐Chung 
Published: October 2002

AbstractTo determine if D2 dopamine receptor‐mediated nuclear signaling is altered during the development of amphetamine sensitization, we examined the expression of immediate‐early gene (IEG) products, Fos, Jun, and Fos‐related antigen (FRA), in both controls and amphetamine‐sensitized rats after a challenge with the D2 antagonist haloperidol. When chronic saline‐ or amphetamine (5 mg/kg, i.p. for 14 days)‐treated rats were challenged with 2 mg/kg haloperidol at withdrawal day 3 (w3), more 35‐kDa FRA was induced in the ventral striatum of the control group than in the amphetamine‐treated rats. In contrast, more Jun and 35‐kDa FRA were expressed in the ventral striatum of the amphetamine‐treated group than in the controls when haloperidol was given at w10. Topographical analyses indicate that the decrease in FRA immunoreactive neuronal density in amphetamine‐treated rats at w3 were located in the dorsolateral caudate/putamen and the nucleus accumbens shell and core subregions. Conversely, the increase in Jun‐immunoreactive neurons in amphetamine‐treated rats at w10 was observed in the dorsolateral caudate/putamen; in the case of the FRAs, the increase was observed in the nucleus accumbens shell. In addition, the time‐dependent profile of IEG expression paralleled the activation of an upstream regulator, cAMP‐response element binding protein, in the ventral striatum after haloperidol treatment. These neurochemical changes may be associated with behavioral plasticity, since amphetamine‐treated rats displayed a lower amount of locomotor activity when exposed to a novel environment at w3, but had recovered at w10. Overall, the current study reveals that there is a distinct temporal and spatial profile of haloperidol‐induced IEG expression and/or CREB phosphorylation in amphetamine‐treated rats, suggesting that there is a critical transition between the early and late withdrawal periods. Synapse 45:230–244, 2002. © 2002 Wiley‐Liss, Inc.
Microcystin‐producing cyanobacteria in recreational waters in southwestern Germany
Authors: Frank Christian A. P. 
Published: October 2002

AbstractToxin‐forming species of freshwater cyanobacteria have been detected in all parts of Germany. Because of the high number of lakes (more than 2000) in Baden‐Württemberg, in southwestern Germany, only a representative selection of lakes (155) was intensively monitored for mass development of cyanobacteria and the formation of toxins in 1999. Nutrients, dominant algal species, chlorophyll, and toxins were determined from waters with cyanobacterial blooms. Toxin analyses were performed using HPLC, the PP1 inhibition test, and the microcystin ELISA. In 45% of the monitored lakes, the phytoplankton assemblage consisted mainly of cyanobacteria; in an additional 24% of the lakes cyanobacteria were detected. More than 26% of the lakes contained toxigenic cyanobacteria. The highest amount of microcystins detected outside scum areas was 11–560 μg/L. In relation to biomass, cyanobacteria contained up to 1100 μg/g dry matter and up to 2.6 μg/μg Chl a. The dominant form of microcystin detected was microcystin‐LR, one of the most toxic known microcystins. The results of the present study have been used to develop a stepwise monitoring scheme for lakes with permanent cyanobacterial populations to protect human health and livestock. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 361–366, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10068
Carbon disulfide cytotoxicity on cultured cardiac myocytes of rats
Authors: Tan Xiaodong , Peng Xiaoxia , Wang Yongdi , Wang Fuyuan , Joyeux Michel , Hartemann Philippe 
Published: October 2002

AbstractAlthough epidemiological studies have suggested that carbon disulfide produces cardiovascular effects in occupationally exposed workers, little is known about its cellular mechanism. The purpose of the present study was to evaluate the functional and histological effects on cardiac myocytes cultured under a condition of carbon disulfide exposure. Cardiac myocytes were isolated from neonatal rat ventricles by trypsin, dispersed and cultured for 3 days in a full Dulbecco's Modified Eagle Medium containing 2% calf serum. Then the myocytes (106 myocytes/mL) were incubated with carbon disulfide at concentrations of 0, 20, 40, and 80 μmol/mL for 24 h. The beating arrest rate of myocytes for each group was examined, succinodehydrogenase (SDH) activity in the myocardial cells was assessed using a cytochemical method, and a morphological examination was performed. We found that the beating arrest rate of cardiac myocytes increased with increasing exposure levels. Vacuolization and pseudopodia could be seen in the cytoplasm of the exposed group. SDH activity decreased with increasing exposure levels. The results suggest that CS2 has a direct and dose‐dependent cytotoxic effect. The biochemical mechanism may be a reduction of the availability of energy (adenosine triphosphate) to cardiac myocytes, resulting in a decrease of contractility by lack of energy. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 324–328, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10070
Possible allelopathic effects of cyanotoxins, with reference to microcystin‐LR, in aquatic ecosystems
Authors: Pflugmacher Stephan 
Published: October 2002

AbstractDuring recent years a shift from macrophyte‐dominated to more phytoplankton‐dominated lakes has been correlated to the process of eutrophication. The existence of numerous substances exhibiting allelopathic effects on the growth of algae has been shown in different aquatic macrophytes (e.g., Myriophyllum spicatum) and is thought to be an important mechanism in stabilizing the macrophyte‐dominated clear‐water state of a lake. A few recent studies have shown that algae themselves can produce special substances inhibiting growth or photosynthetic processes in other algae. A well‐known cyanobacterial secondary metabolite, microcystin‐LR, was tested for its allelopathic power on aquatic macrophytes such as Ceratophyllum demersum and Myriophyllum spicatum, resulting in growth inhibition, reduction in photosynthetic oxygen production, and changes in pigment pattern. This shows that microcystin‐LR has a possible role as an allelopathic infochemical. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 407–413, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10071
Rotational augmentation of horizontal axis wind turbine blade aerodynamic response
Authors: Schreck S. , Robinson M. 
Published: October 2002

AbstractSurface pressure data were acquired using the NREL Unsteady Aerodynamics Experiment, a full‐scale horizontal axis wind turbine, which was erected in the NASA Ames 80 ft × 120 ft wind tunnel. Data were collected first for a stationary blade and then for a rotating blade with the rotor disc at zero yaw. Analyses compared aerodynamic forces and surface pressure distributions under rotating conditions against analogous baseline data acquired from the stationary blade. This comparison allowed rotational modifications to blade aerodynamics to be characterized in detail. Rotating conditions were seen to dramatically amplify aerodynamic forces and radically alter surface pressure distributions. These and subsequent findings will more fully reveal the structures and interactions responsible for these flow field enhancements and help establish the basis for formalizing comprehension in physics‐based models. Copyright © 2002 John Wiley & Sons, Ltd.
Homing at an extragenic locus mediated by VDE (PI‐SceI) in Saccharomyces cerevisiae
Authors: Nogami Satoru , Fukuda Tomoyuki , Nagai Yuri , Yabe Shizu , Sugiura Masako , Mizutani Ryuta , Satow Yoshinori , Anraku Yasuhiro , Ohya Yoshikazu 
Published: October 2002

AbstractPI‐SceI (VDE), a homing endonuclease with protein splicing activity, is a genomic parasite in the VMA1 gene of Saccharomyces cerevisiae. In a heterozygous diploid of the VDE‐less VMA1 allele and a VDE‐containing VMA1 allele, VDE specifically cleaves its recognition sequence (VRS) in the VDE‐less VMA1 allele at meiosis, followed by ‘homing’, i.e. a conversion to a VDE‐containing allele. We found that upon VDE expression, homing of a marker gene at an extragenic locus occurs only when a 45 bp element containing the VRS is inserted at its allelic site, while mutants of VDE with no endonuclease activity lack authentic extragenic homing activity. Thus, both the VRS and VDE are required for homing. Insertion of the VRS in a homozygous diploid significantly lowered the spore germination ability, indicating that a template for gene repair at its allelic locus is essential for efficient homing and survival of yeast cells. Copyright © 2002 John Wiley & Sons, Ltd.
Duikers: Native food composition, micronutrient assessment, and implications for improving captive diets
Authors: Dierenfeld Ellen S. , Mueller Pamela J. , Hall Mary Beth 
Published: October 2002

AbstractThis review summarizes and contrasts published information on the proximate chemical composition of native fruits and leaves eaten by duikers, and adds new data concerning the soluble carbohydrate, mineral, and tannin content of duiker foods. Information on circulating plasma concentrations of minerals and the fat‐soluble vitamins A and E is also summarized in relation to free‐ranging vs. zoo‐held duikers and differences in the nutrient content of their respective diets. In nature, duikers consume diets containing low starch (in general <0.1% of dry matter (DM)) and moderate‐to‐high fiber (averaging 32% DM) and protein (fruits <10%, leaves <20% DM) levels, and do not avoid foodstuffs containing tannins. Native food samples were considered low to marginal in calcium (Ca) and phosphorus (P) content compared with domestic ruminant dietary requirements, but Ca levels were generally two‐ to threefold higher than P concentrations. Diets fed to duikers in captivity are often low in fiber and tannin content, and high in starch and protein, as well as low in Ca relative to P (compared with native plants), which may lead to nutrient imbalances and health problems. Plasma alpha‐tocopherol values measured in zoo duikers ranged from 0.4 to 8.3 μg/ml, and were less variable in free‐ranging animals (1.7–7.0 μg/ml). Retinol values did not differ among duiker species or between sample populations, and were within normal ranges (0.2–0.7 μg/ml) expected for herbivores. Domestic hoofstock appear to be suitable physiological models for evaluating fat‐soluble vitamin status, but mineral homeostasis appears to differ in duikers. Free‐ranging duikers have somewhat higher Ca, and lower P concentrations compared with captive‐held individuals, and inverse Ca:P ratios and copper (Cu) deficiency have been reported in captive duikers—both conditions in which captive diet may play a key role. A frugivorous browser pellet/diet that incorporates the findings summarized here, and better duplicates the chemical complement described for native foods eaten by duikers, may provide health benefits to these small concentrate selectors. Zoo Biol 21:185–196, 2002. © 2002 Wiley‐Liss, Inc.
Stimulation of DNA synthesis in skin fibroblasts by human hepatocyte growth factor/scatter factor.
Authors: Kataoka Hirotoshi , Gohda Eiichi , Matsunaga Tetsuhiko , Ishii Takehisa , Hara Hiroto , Yamamoto Itaru 
Published: October 2002

AbstractThe effect of hepatocyte growth factor/scatter factor (HGF/SF) on the proliferation of human skin fibroblasts was examined. At concentrations above 1.0 ng/ml, both native and recombinant human HGF/SF stimulated the DNA synthesis determined by [3H]thymidine incorporation, which was completely inhibited by an anti‐human HGF/SF monoclonal antibody. The maximal DNA synthesis in the treated cells was nearly twice that in untreated cells. HGF/SF also caused an increase in the labelling index, DNA content and cell number. The effect of HGF/SF was more than additive to the maximal effect of insulin and epidermal growth factor, other mitogens for the fibroblasts. These results indicate that human skin fibroblasts are sensitive to the mitogenic action of HGF/SF.
No change in bone‐specific alkaline phosphatase activities in cultured rat osteoblastic cells under L‐ascorbate and β‐glycerophosphate‐induced mineralization
Authors: Chak C. W. , Lee K. M. , Leung K. S. , Fung K. P. 
Published: October 2002

AbstractMineralization occurred both in fetal rat calvarial cells and UMR 106 osteoblastic cells when they were cultured in medium containing L‐ascorbate and β‐glycerophosphate as evidenced by von Kóssa staining as well as deposition of calcium ions and inorganic phosphate in the cells. When compared with corresponding non‐mineralized cell cultures, both the mineralized cultures of calvarial cells and UMR 106 cells did not exhibit any change in intracellular bone‐specific alkaline phosphatase activities which were measured by wheatgerm lectin precipitation method. Our results support the hypothesis that mineralization may not exert any direct negative feedback on matrix protein synthesis in osteoblasts during bone formation.
TISSUE TRANSGLUTAMINASE EXPRESSION IN QUAIL EPIPHYSEAL CHONDROCYTES
Authors: Gionti Elisa , Sanchez Massimo , Arcella Antonietta , Pontarelli Gianfranco , Tavassi Simona , Gentile Vittorio , Cozzolino Anna , Porta Raffaele 
Published: October 2002

Tissue transglutaminase (tTGase) is a GTP‐binding Ca2+‐dependent enzyme which catalyses the post‐translational modification via ∍(γ‐glutamyl)lysine bridges. The physiological role of tTGase is not fully understood. It has been shown that in cartilage the expression of tTGase correlates with terminal differentiation of chondrocytes. Recent evidence suggests that the GTP‐binding activity of tTGase may play a role in the control of cell cycle progression thus explaining some of the suggested roles for the enzyme.tTGase activity is present in primary cultures of epiphyseal chondrocytes and increases transiently upon retinoic acid (RA) treatment. Increase in enzyme activity occurs upon RA addition and is accompanied by a parallel increase in protein and mRNA levels. Stimulation of tTGase expression by RA correlates with suppression of cell growth and occurs independently of cell adhesion and cell differentiation.tTGase expression is not observed in MC2, a permanent chondrocyte cell line derived from retrovirus infected chondrocytes. RA treatment fails to activate tTGase expression in MC2 cells and to completely suppress cell proliferation.Our findings lend support to the idea that tTGase might play a role in non‐dividing cultured chondrocytes.
DECREASED INTRACELLULAR PROTEOLYSIS CORRELATES WITH THE MAINTENANCE OF A SPECIFIC ISOENZYME OF CYTOCHROME P‐450
Authors: Evans Peter J. 
Published: October 2002

AbstractThe rates of intracellular protein degradation, of identically labelled populations of proteins, were compared in hepatocytes cultured at 37° (on an adsorbed collagen layer) and in cells preserved on gelatin gels at 10°C. The half‐lives of the long‐lived proteins were 35.4±8.6h (N=4) and 692.9±216.9h (N=4) respectively. Proteolysis was substantially decreased at 10°C but the rate of decrease remained constant. Hepatocytes rapidly removed resorufin from the culture medium. The resorufin was not being conjugated or accumulated within the cells. Dicumarol, a potent inhibitor of quinone oxidoreductase, at high concentration (500μm) caused only a 72% decrease in the utilization of resorufin. The microsomal detoxifying enzyme, cytochrome P‐450 1A1 remained at a constant level in the preserved hepatocyte monolayers. The results of this study strongly favour storing hepatocytes at 10°C rather than at 4° or 37°C.
Unstable Behavior of the Laurentide Ice Sheet over Deforming Sediment and Its Implications for Climate Change
Authors: Clark Peter U. 
Published: October 2002

AbstractGeologic records of fluctuations of the Laurentide ice sheet margin following the most recent glacial maximum (ca.20,00014C yr B.P.) identify fundamental differences in ice-sheet behavior depending on subglacial bed conditions. Rapid and irregular icemargin fluctuations occurred only over areas of deforming sediment, indicating nonclimatic forcing controlled by the inherent instability of coupled ice sheet-deforming sediment dynamics. In contrast, largely uninterrupted ice-margin retreat with no evidence of significant readvance occurred over rigid-bed areas, indicating stable behavior. Unstable ice-sheet behavior was most pronounced from 15,000 until 10,00014C yr B.P., by which time most of the ice margin had retreated onto a rigid bed. Unstable ice-sheet behavior would have been an integral component in controlling variable fluxes of icebergs and meltwater, as well as meltwater routing, to the North Atlantic, thus affecting thermohaline circulation. The abrupt climate oscillations in the North Atlantic region that ended at 10,00014C yr B.P. may thus have their origin in the inherently unstable behavior of the Laurentide ice sheet overriding deforming sediment.
Paleoecological Studies of a Holocene Lacustrine Record from the Kangerlussuaq (Søndre Strømfjord) Region of West Greenland
Authors: Eisner Wendy R. , Törnqvist Torbjörn E. , Koster Eduard A. , Bennike Ole , van Leeuwen Jacqueline F.N. 
Published: October 2002

AbstractA lacustrine sediment record from the Kangerlussuaq region, West Greenland, has resulted in a pollen, macrofossil, and sediment stratigraphy that encompasses the last 500014C yr. Deglaciation of the area and subsequent development of a nearby floodplain occurred before 5000 yr B.P. Since that time eolian sand and silt deposition appear to have been continuous, with a significant increase ca. 100014C yr B.P. Pollen analysis shows little change in the character of the vegetation throughout the record. Fluctuations in herb pollen taxa indicate changes in the extent and development of eolian sand sheets. The oldest pollen zone records relatively little pollen accumulation and low taxa diversity. This is followed by a zone of high pollen accumulation, presumably a phase of highest vegetation density, from 4400 to 340014C yr B.P. Thereafter, declining pollen accumulation rates reveal a gradual environmental deterioration. Macrofossil analyses record significant limnological changes, with an early eutrophic phase followed by a masotrophic phase and a reversal to more eutrophic conditions in the final phase. The preserved record illustrates the interactions of deglaciation, eolian activity, regional vegetation, and limnological change.