bluuebunny/crossref_metadata_2025_split huggingface dataset:
Actin polymerization in the equatorial and postacrosomal regions of guinea pig spermatozoa during the acrosome reaction is regulated by G proteins
Authors: Delgado‐Buenrostro Norma Laura , HernÁndez‐GonzÁlez Enrique O. , Segura‐Nieto Magdalena , MÚjica Adela 
Published: November 2004

AbstractThe acrosome reaction (AR) is an exocytotic process of spermatozoa, and an absolute requirement for fertilization. During AR, actin polymerization is necessary in the equatorial and postacrosomal regions of guinea pig sperm for spermatozoa incorporation deep into the egg cytoplasm, but not for plasma membrane (PM) fusion nor the early steps of egg activation. To identify the mechanisms involved in this sperm actin polymerization, we searched for the protein members, known to be involved in a highly conserved model, that may apply to any cellular process in which de novo actin polymerization occurs from G protein activation. WASP, Arp 2/3, profilins I and II, and Cdc42, RhoA and RhoB GTPases were localized by indirect immunofluorescence (IIF) in guinea pig spermatozoa and their presence corroborated by Western blotting. WASP and profilin II were translocated to the postacrosomal region (Arp2/3 already were there) in long‐term capacitated and acrosome‐reacted spermatozoa, at the same time as actin polymerization occurred. These events were inhibited by GDP‐β‐S and promoted by lysophosphatidic acid (LPA) and GTP‐γ‐S, a small GTPase inhibitor and two activators, respectively. By immunoprecipitation, Cdc42–WASp association was identified in capacitated but not in noncapacitated gametes. Polymerized actin in the postacrosomal region is apparently anchored both to the postacrosomal perinuclear theca region and the overlying PM. Results suggest that GTPases are involved in sperm actin polymerization, in the postacrosomal region and the mechanism for polymerization might fit a previously proposed model (Mullins, 2000: Curr Opin Cell Biol 12:91–96). Mol. Reprod. Dev. 70: 198–210, 2005. © 2005 Wiley‐Liss, Inc.
Androstenedione increases cytochrome P450 aromatase messenger ribonucleic acid transcripts in nonluteinizing bovine granulosa cells
Authors: Hamel Mélanie , Vanselow Jens , Nicola Edmir S. , Price Christopher A. 
Published: November 2004

AbstractThe objective of this study was to determine if androgens regulate granulosa cell steroidogenesis at physiological doses found in small bovine follicles. Bovine granulosa cells were cultured under serum‐free conditions that permit the induction and maintenance of FSH‐dependent estradiol secretion. Increasing androstenedione concentrations from 0.1 to 1 or 10 μM significantly increased estradiol accumulation and cytochrome P450 aromatase (P450arom) mRNA abundance. No increase in progesterone accumulation or abundance of mRNA for P450 side‐chain cleavage or 3β‐hydroxysteroid dehydrogenase enzymes was observed. The addition of 0.1, 1, or 10 μM progestins or estrogens had no stimulatory effect on P450arom mRNA levels. An analysis of the 5′‐untranslated region of P450arom mRNA transcripts indicated that the majority was derived from Cyp19 ovary‐specific promoter 2, with some contribution from promoters 1.1 and 1.5. Transcripts from these three promoters were all significantly increased by androstenedione. Testosterone increased promoter 1.1 and 1.5‐derived transcripts, but only promoter 2‐derived transcripts at the highest dose tested (100 μM). Dihydrotestosterone (DHT) did not affect Cyp19 expression. Collectively, these data show that androgens may exert specific stimulatory effects on P450arom mRNA concentrations in granulosa cells. Interestingly, different androgens had different effects on Cyp19 promoter usage, suggesting differential regulation of aromatase gene expression in the developing follicle. Mol. Reprod. Dev. 70: 175–183, 2005. © 2005 Wiley‐Liss, Inc.
Matrix metalloproteinase‐2 (MMP‐2) expression and regulation by tumor necrosis factor alpha (TNFα) in the bovine corpus luteum
Authors: Zhang Bo , Yan Li , Tsang Paul C.W. , Moses Marsha A. 
Published: November 2004

AbstractAngiogenesis and tissue remodeling events in the corpus luteum (CL) are mediated by matrix metalloproteinases (MMPs). We have recently reported the cloning of bovine membrane‐type 1 metalloproteinase (MT1‐MMP) and have shown that active MT1‐MMP is correlated to MMP‐2 activity in the CL during the estrous cycle. Given the important role that MMP‐2 plays in neovascularization, we became interested in understanding the role of this enzyme in the CL, a system in which angiogenesis is exquisitely regulated in the course of its lifespan. The aims of the present study were to clone bovine MMP‐2 cDNA, to investigate its temporal and spatial expression in three stages of CL during the estrous cycle and to study its regulation by TNFα, a key cytokine regulator of CL physiology. Bovine MMP‐2 cDNA was isolated from a UNI‐ZAP II bovine capillary endothelial cell cDNA library and sequenced. This gene encoded a protein of 662 amino acids. Luteal tissues were collected from non‐lactating dairy cows on days 4, 10, and 16 of the estrous cycle. Northern and Western blotting revealed that the levels of MMP‐2 mRNA (3.1 kb) and immunoreactive pro‐MMP‐2 protein (68 kDa) did not differ (P > 0.05) in any age of CL examined. In addition to large luteal cells, MMP2 was localized to endothelial cells in all ages of CL by immunohistochemistry. Studies using in vitro luteal cell cultures showed that MMP‐2 mRNA, protein expression and activity was upregulated by TNFα in a dose‐ and time‐dependent manner. The present study suggests that MMP‐2 is predominantly produced by large luteal cells and endothelial cells, and that it plays an essential role in luteal remodeling and angiogenesis. These data also suggest that cytokines such as TNFα may modulate these processes by regulating MMP‐2 expression. Mol. Reprod. Dev. 70: 122–132, 2005. © 2005 Wiley‐Liss, Inc.
Major hazard risk assessment for existing and new facilities
Authors: Filippin Katherine (Kate) , Dreher Lachlan 
Published: November 2004

AbstractThis paper outlines a risk assessment methodology that has been developed through work with major hazard facilities, including ammonia plants in Australia, satisfying regulations equivalent to the European Seveso II Directive. The methodology is an approach for ensuring an undertaking of effectively assessing the risks associated with major hazards that will not only satisfy regulations and corporate requirements, but also, more importantly, provide a framework for sustainable business processes, by enabling the methodology to be integrated into normal business management processes. The approach enables existing management systems to be effectively incorporated into the evaluation processes. Common pitfalls encountered during the risk assessment process are also discussed. © 2004 American Institute of Chemical Engineers Process Saf Prog, 2004
Structural assessment and strengthening measures for a cantilevered road deck
Authors: Zwicky Daia , Vogel Thomas , Guidotti Nicola 
Published: November 2004

AbstractStarting from the investigation of the simple case of a cantilevered road deck, this paper attempts to demonstrate that deeper investigations of a structural safety problem may lead to significant modifications of the goals of the investigation.The assignment by the owner authority consisted of assessing the bending moments due to traffic loads, above all from axle loads, at the clamping of a cantilevered slab and to propose appropriate measures if needed. The slab carries the road deck, being the hard shoulder of the Swiss North–South motorway close to the Italian border.In a first step, the regular axle loads of the new Swiss action code are applied to calculate the inner forces by simple hand calculations. It is found that the shear resistance is noticeably more critical than the bending resistance, considering both the new Swiss structural concrete code as well as, for reasons of comparison, Eurocode 2.In a second step, the reduction of the axle loads is investigated considering actualised load models developed for the assessment of existing road bridges. It is found that applying these models achieves structural safety in large parts of the structure, but that other parts still exhibit insufficient structural safety.In the third part, the possible range of strengthening measures is investigated. It is pointed out that every strengthening method should be carefully checked for its application conditions and the corresponding consequences. Qualitative criteria are adequate to judge a specific strengthening method in a certain situation. The last part of the paper discusses the effectively executed measures.Conclusions on the application of the findings from the paper to other assessment situations are drawn.
A study on montmorillonite/polyethylene nanocomposite extrusion‐coated paperboard
Authors: Krook M. , Gällstedt M. , Hedenqvist M. S. 
Published: November 2004

AbstractExtrusion coating was used to obtain montmorillonite/polyethylene‐coated paperboard. The coating was prepared from a master batch containing maleated polyethylene, low‐density polyethylene and 32 wt.% polyvinylpyrrolidone‐surface‐modified montmorillonite clay, which was blended with different amounts of low‐density polyethylene to yield composites with 4 wt.% and 8.3 wt.% montmorillonite. X‐ray diffraction revealed that the clay stacks in the coating were more extensively intercalated than in the original surface‐modified clay. Transmission electron microscopy showed that the clay stacks were, to a large extent, separated by the high shear forces during extrusion into smaller evenly distributed entities. This was, unfortunately, achieved at the expense of the formation of a great many voids and pinholes, as revealed by transmission electron microscopy and dye staining. This had strong negative effects on the oxygen barrier properties but only a modest effect on the water vapour permeability. Tensile tests showed that the coating was always ductile and that the coating–paperboard adhesion decreased with increasing clay content. The creasability was good and unaffected by the presence of the filler in the coating. Thermogravimetry showed that the degradation temperature in air of the filled coatings were of the order of 10°C higher than that of unfilled polyethylene. Copyright © 2004 John Wiley & Sons, Ltd.
Characterization of moulded‐fibre packaging with respect to water vapour sorption and permeation at different combinations of internal and external humidity
Authors: Sørensen Gitte , Risbo Jens 
Published: November 2004

AbstractA moulded‐fibre packaging system was characterized under conditions simulating real‐life packaging of food. A steady‐state moisture flux through the moulded‐fibre packaging was generated by subjecting the system to different combinations of internal humidity [33–97% r.h. (0.33–0.97aw of contents), RH(i)] and surrounding humidity [33–97% r.h., RH(e)]. The objective was to resolve whether a hygroscopic fibre material absorbs moisture proportional to the rate of moisture transport, and the moulded‐fibre material was thus characterized with respect to accumulation of moisture in the fibre material, water vapour transmission rate (WVTR) and permeability (k/x). These steady‐state properties showed significant asymmetry depending on direction of moisture transport. When moisture was transported out of the system [RH(i) > RH(e)] the fibre material adsorbed moisture to a considerable lesser extent compared to when moisture was transported into the system [RH(i) < RH(e)], just as (k/x) increased by 15–20%. Taking both directions of moisture transport into account, the moisture content of the fibre material depended largely on surrounding humidity, even at high internal humidity. Moisture contents ranged from 5.5 g/100 g dry fibre at RH(e) 33% r.h. to 16.4–25.1 g/100 g dry fibre at RH(e) 97% r.h. The observed asymmetry was shown to derive from the experimental set‐up and not from the material itself. A minimal theory based on the various transport steps in the experimental set‐up was proposed in order to qualitatively explain this asymmetry. The rate of moisture adsorption in moulded‐fibre was described by the normalized response function H(t). Response times to reach equilibrium moisture contents were 6 and 8 h for RH(e) 33 and 53% r.h., and 40 and 41 h for RH(e) 75 and 97% r.h. Copyright © 2004 John Wiley & Sons, Ltd.
Structural characterization of methionine and leucine enkephalins by hydrogen/deuterium exchange and electrospray ionization tandem mass spectrometry
Authors: Cai Xianmei , Dass Chhabil 
Published: November 2004

AbstractConformational changes in two endogenous opioid active pentapeptides methionine enkephalin (Met‐enk) and leucine enkephalin (Leu‐enk) induced by trifluoroethanol (TFE) were identified using hydrogen/deuterium exchange (HDX), coupled with electrospray ionization (ESI) mass spectrometry. The exchange features in individual amino acid residues were characterized by acquiring tandem mass spectra of the deuterated peptides. The exact identity of the labile hydrogens involved in HDX reveals that the monomer forms of both peptides adopt an unfolded conformation in aqueous solvent, but prefer the 5→2 β‐turn secondary structure under the membrane‐mimetic environment. The ESI mass spectra of Met‐enk and Leu‐enk also reveal that the dimer structure of these peptides coexists with the monomer conformation. The extent of the dimer structure is dependent on the peptide concentration and nature of the solvent. The non‐polar solvents facilitate the dimer formation. Copyright © 2004 John Wiley & Sons, Ltd.
Mundschutz
Authors: Romeike Frank 
Published: November 2004

AbstractIn der Nacht vom 2. auf den 3. Dezember 1984 — also exakt vor zwanzig Jahren — ereignete sich im indischen Bhopal eine der größten Katastrophen in der chemischen Industrie. In einem Tochterwerk der Union Carbide Corporation explodierte ein Tank mit 40 Tonnen Methylisocyanat (MIC), die tödlichen Gase breiteten sich unmittelbar in der Atmosphäre aus. Die Zahl der Todesopfer wird mit etwa 5.000 bis 10.000 beziffert. Die Schätzungen über die Anzahl der chronisch Geschädigten schwanken zwischen 300.000 und 500.000 Menschen. Und noch immer ist das Trinkwasser verseucht. Bis heute kämpfen die Opfer um eine Entschädigung für ihre Leiden und gesundheitlichen Beeinträchtigungen. Eine Mitursache für die Katastrophe von Bhopal war unter anderem die fatalistische Einstellung der Unternehmensleitung, da „… ein paar Unfälle dann und wann […] der notwendige Preis für die Produktion”︁ seien.
Funnel plots for comparing institutional performance
Authors: Spiegelhalter David J. 
Published: November 2004

Abstract‘Funnel plots’ are recommended as a graphical aid for institutional comparisons, in which an estimate of an underlying quantity is plotted against an interpretable measure of its precision. ‘Control limits’ form a funnel around the target outcome, in a close analogy to standard Shewhart control charts. Examples are given for comparing proportions and changes in rates, assessing association between outcome and volume of cases, and dealing with over‐dispersion due to unmeasured risk factors. We conclude that funnel plots are flexible, attractively simple, and avoid spurious ranking of institutions into ‘league tables’. Copyright © 2004 John Wiley & Sons, Ltd.
The impact of diagnostic error on testing genetic association in case–control studies
Authors: Zheng Gang , Tian Xin 
Published: November 2004

AbstractIn case–control studies, subjects in the case group may be recruited from suspected patients who are diagnosed positively with disease. While many statistical methods have been developed for measurement error or misclassification of exposure variables in epidemiological studies, no studies have been reported on the effect of errors in diagnosing disease on testing genetic association in case–control studies. We study the impact of using the original Cochran–Armitage trend test assuming no diagnostic error when, in fact, cases and controls may be clinically diagnosed by an imperfect gold standard or a reference test. The type I error, sample size and asymptotic power of trend tests are examined under a family of genetic models in the presence of diagnostic error. The empirical powers of the trend tests are also compared by simulation studies under various genetic models. Published in 2004 by John Wiley & Sons, Ltd.
Bayesian inference for recurrent events data using time‐dependent frailty
Authors: Manda Samuel O. M. , Meyer Renate 
Published: November 2004

AbstractIn medical studies, we commonly encounter multiple events data such as recurrent infection or attack times in patients suffering from a given disease. A number of statistical procedures for the analysis of such data use the Cox proportional hazards model, modified to include a random effect term calledfrailtywhich summarizes the dependence of recurrent times within a subject. These unobserved random frailty effects capture subject effects that are not explained by the known covariates. They are typically modelled constant over time and are assumed to be independently and identically distributed across subjects. However, in some situations, the subject‐specific random frailty may change over time in the same manner as time‐dependent covariate effects. This paper presents a time‐dependent frailty model for recurrent failure time data in the Bayesian context and estimates it using a Markov chain Monte Carlo method. Our approach is illustrated by a data set relating to patients with chronic granulomatous disease and it is compared to the constant frailty model using the deviance information criterion. Copyright 2004 © John Wiley & Sons, Ltd.
Multi‐project software engineering analysis using systems thinking
Authors: Lee Bengee , Miller James 
Published: November 2004

AbstractSoftware organizations often have multiple projects developed concurrently, the efficient and effective management of human resources in such a situation is essential if an organization is to prosper and flourish. The article argues that to analyze it systematically, we need to explore systems thinking and dynamics. The article then develops a number of systems dynamics models that model human resources and their associated productivity in such a multi‐project environment. However, systems thinking alone lacks the capability to construct a multi‐project scheduling network. Thus, this research also investigates the integration of systems thinking with a multi‐project network constructing method, calledCritical Chain Project Managementto provide a flexible scheduling mechanism. Furthermore, in order to portray unexpected situations, scenario planning is incorporated into the system to allow project managers to explore these situations and their impact on the production processes. This unique architecture allows the project manager to identify the restraining factors in various possible scenarios, to provide feasible managerial solutions and assist with optimal planning in this complex environment. Copyright © 2004 John Wiley & Sons, Ltd.
Striking Differences in Individual Anticonvulsant Response to Phenobarbital in Rats with Spontaneous Seizures after Status Epilepticus
Authors: Brandt Claudia , Volk Holger A. , Löscher Wolfgang 
Published: November 2004

Summary:  Purpose: More than one third of patients with epilepsy have inadequate control of seizures with drug therapy, but mechanisms of intractability are largely unknown. Because of this large number of pharmacoresistant patients with epilepsy, the existing process of antiepileptic drug (AED) discovery and development must be reevaluated with a focus on preclinical models of therapy‐resistant epilepsy syndromes such as mesial temporal lobe epilepsy (TLE). However, although various rodent models of TLE are available, the pharmacoresponsiveness of most models is not well known. In the present study, we used a post–status epilepticus model of TLE to examine whether rats with spontaneous recurrent seizures (SRSs) differ in their individual responses to phenobarbital (PB). Methods: Status epilepticus was induced in Sprague–Dawley rats by prolonged electrical stimulation of the basolateral amygdala. Once the rats had developed SRSs, seizure frequency and severity were determined by continuous EEG/video recording over a 6‐week period (i.e., a predrug control period of 2 weeks, followed by PB treatment for 2 weeks, and a postdrug control period of 2 weeks). PB was administered twice daily at maximal tolerated doses. Results: Analysis of plasma drug concentrations showed that drug concentrations within the therapeutic range (10–40 μg/ml) were maintained in all rats throughout the period of treatment. In six (55%) of 11 rats, complete control of seizures was achieved, and another rat exhibited a >90% reduction of seizure frequency. These seven rats were considered responders. The remaining four (36%) rats showed either no response at all (n = 3) or only moderate reduction in seizure frequency and were therefore considered nonresponders. Plasma drug concentrations did not differ between these two groups of rats. Conclusions: These data demonstrate that, similar to patients with epilepsy, rats with SRSs markedly differ in their individual responses to AED treatment. Pharmacoresistant rats selected by prolonged drug treatment from groups of rats with SRSs may provide a unique model to study mechanisms of pharmacoresistance and to identify novel AEDs for treating seizures of patients currently not controlled with existing therapies.
Effects of Add‐on Melatonin Administration on Antioxidant Enzymes in Children with Epilepsy Taking Carbamazepine Monotherapy: A Randomized, Double‐blind, Placebo‐controlled Trial
Authors: Gupta Madhur , Gupta Yogendra Kumar , Agarwal Sarita , Aneja Satinder , Kalaivani Mani , Kohli Kamlesh 
Published: November 2004

Summary:  Purpose: Melatonin has been shown to exhibit antioxidant, antiexcitotoxic, and free radical–scavenging properties in various animal models. The study was designed to assess its effects on the blood levels of antioxidant enzymes in children with epilepsy receiving carbamazepine (CBZ). Methods: In a double‐blind, randomized, parallel‐group, placebo‐controlled trial, we assessed the effect of add‐on melatonin (6–9 mg/day for 14 days) on the antioxidant enzymes glutathione peroxidase (GPx) and glutathione reductase (GRd) in 31 children with epilepsy receiving CBZ monotherapy, who were seizure free at least for the last 6 months. The interaction of melatonin with CBZ and its active metabolite, carbamazepine‐10, 11‐epoxide (CBZ‐E), also was studied. Results: An increase in GRd activity was noted in the melatonin group as compared with a decrease of the same enzyme in the placebo group. Changes in GPx activity failed to reach statistical significance. No significant changes were found in the serum levels of CBZ and CBZ‐E in either group. Conclusions: The study suggests that melatonin exerts antioxidant activity in patients with epilepsy receiving CBZ therapy.