bluuebunny/crossref_metadata_2025_split huggingface dataset:
The self‐organization of the European Information Society: The case of “biotechnology”
Authors: Leydesdorff Loet , Heimeriks Gaston 
Published: August 2002

AbstractFields of technoscience like biotechnology develop in a network mode: disciplinary insights from different backgrounds are recombined as competing innovation systems are continuously reshaped. The ongoing process of integration at the European level generates an additional network of transnational collaborations. Using the title words of scientific publications in five core journals of biotechnology, multivariate analysis is used to distinguish between the intellectual organization of the publications in terms of title words and the institutional network in terms of addresses of documents. The interaction among the representation of intellectual space in terms of words and co‐words, and the potentially European network system is compared with the document sets with American and Japanese addresses. The European system can also be decomposed in terms of the contributions of member states. Whereas a European vocabulary can be made visible at the global level, this communality disappears by this decomposition. The network effect at the European level can be considered as institutional more than cognitive.
A reliability semi‐Markov model involving geometric processes
Authors: Pérez‐Ocón Rafael , Torres‐Castro Inmaculada 
Published: August 2002

AbstractWe consider a semi‐Markov process that models the repair and maintenance of a repairable system in steady state. The operating and repair times are independent random variables with general distributions. Failures can be caused by an external source or by an internal source. Some failures are repairable and others are not. After a repairable failure, the system is not as good as new and our model reflects that. At a non‐repairable failure, the system is replaced by a new one. We assume that external failures occur according to a Poisson process. Moreover, there is an upper limit N of repairs, it is replaced by a new system at the next failure, regardless of its type. Operational and repair times are affected by multiplicative rates, so they follow geometric processes. For this system, the stationary distribution and performance measures as well as the availability and the rate of occurrence of different types of failures in stationary state are calculated. Copyright © 2002 John Wiley & Sons, Ltd.
Absence of pharmacokinetic interaction between orally co‐administered naproxen sodium and diphenhydramine hydrochloride
Authors: Toothaker R.D. , Barker S.H. , Gillen M.V. , Helsinger S.A. , Kindberg C.G. , Hunt T.L. , Powell J.H. 
Published: August 2002

AbstractThe potential for a pharmacokinetic interaction between naproxen and diphenhydramine was examined in a randomized three‐way crossover design with a 1‐week washout between dosing. Single oral doses of 220 mg of naproxen sodium and 50 mg of diphenhydramine hydrochloride were given separately and together to 30 healthy male and female subjects. Heparinized blood samples obtained for 48 h postdose were assayed for plasma naproxen and diphenhydramine concentrations using validated high‐performance liquid chromatography (HPLC) and gas chromatography (GC) assay methods, respectively. The area under the plasma concentration–time curve (AUC), maximum plasma concentrations (Cmax), time of Cmax (Tmax) and terminal exponential half‐life (t1/2,z), were analysed for significant treatment differences by analysis of variance (ANOVA). Based on absence of significant treatment effects on AUC and Cmax, single‐dose oral co‐administration of 220 mg of naproxen sodium with 50 mg of diphenhydramine hydrochloride does not alter the pharmacokinetics of either naproxen or diphenhydramine. Significant treatment differences seen for naproxen Tmax (0.3 h, males only) and diphenhydramine t1/2,z (0.8 h, females only) were minor and are unlikely to have therapeutic consequences. Thus, efficacy and safety of concomitant naproxen and diphenhydramine should not be altered due to a pharmacokinetic interaction. Copyright © 2000 John Wiley & Sons, Ltd.
Linezolid absolute bioavailability and the effect of food on oral bioavailability
Authors: Welshman Ian R. , Sisson Theresa A. , Jungbluth Gail L. , Stalker Dennis J. , Hopkins Nancy K. 
Published: August 2002

AbstractLinezolid is a novel oxazolidinone antibiotic that has a spectrum of activity encompassing a variety of Gram‐positive bacteria. The objectives of this study were twofold: (1) to compare the absorption of linezolid tablets given immediately following a high‐fat meal with the absorption of tablets administered while fasting, and (2) to assess the bioavailability of a 375‐mg oral dose given while fasting relative to a 375‐mg dose of linezolid sterile solution given intravenously. Venous blood samples were taken over the 48 h following the single dose administration of both the oral and intravenous (IV) treatment. Samples were subsequently frozen for the determination of linezolid concentrations by HPLC. The only statistically significant difference between the fasted and the fed treatment was in peak plasma concentration, with the mean Cmax for fasted subjects being 23% greater than that for subjects after consumption of a high‐fat meal. Comparable AUC0–∞ values were measured under both conditions, indicating that the overall extent of absorption is the same. Therefore, the difference in Cmax, while statistically significant, should not affect the therapeutic efficacy of linezolid when it is administered with food. There were no statistically significant differences in AUC0–∞, CL or half‐life between the fasted oral treatment and the intravenous treatment. As expected, Cmax was statistically different between the two treatments. However, the mean absolute bioavailability (F) of the tablet, using the IV sterile solution as the reference treatment, was 103% (±20%). Copyright © 2001 John Wiley & Sons, Ltd.
The same but different: an empirical investigation of the reducibility principle
Authors: Budescu David V. , Fischer Ilan 
Published: August 2002

AbstractAccording to classical utility theory the valuation of any lottery should depend only on its outcomes and their respective probabilities, and should not be affected by the nature, complexity and structure of the chance mechanism. Previous research has documented systematic violations of this principle. For example, most subjects prefer lotteries in which the payoffs are contingent on the joint occurrence of multiple (high probability) events to simple lotteries, and lotteries in which the earlier stages offer higher probabilities than the later stages. We review the various violations of this principle and suggest a classification into two major types associated with misunderstanding of chance mechanisms and attitude towards the chance mechanism and process. In the present study 40 subjects were presented with 30 pairs of binary gambles. In any given pair the lotteries had identical outcomes and equal ‘reduced’ probabilities (and thus equal expected values). However, the chance mechanisms varied along a variety of factors such as the size of the sample space, the number of stages, temporal ordering, order of probabilities, their transparency and time constraints. Half the subjects saw lotteries involving gains and the other half considered only losses. After choosing one lottery in each pair, the subjects were asked to explain and justify their choices. The findings revealed systematic violations of the reducibility principle: subjects displayed a preference for lotteries with larger sample spaces, and for lotteries that allow quicker resolutions in the earlier stages. A clear distinction between some patterns of preferences in the gains and loss domains was revealed. In gambles involvinggainssubjects preferred to have the highest probability on the first stage (and the lowest probability on the last stage), but displayed the opposite preferences forlosses. A content analysis of the subjects' stated reasons for their choices identified eight major categories. The most frequently invoked were hope, fun, simplicity, stress and time. Copyright © 2001 John Wiley & Sons, Ltd.
Effects of exposure to low level radiofrequency fields on acetylcholine release in hippocampus of freely moving rats
Authors: Testylier G. , Tonduli L. , Malabiau R. , Debouzy J.C. 
Published: August 2002

AbstractSome central cholinergic effects have been reported in animals after acute exposure to radiofrequency electromagnetic field at low intensity. We studied acetylcholine (ACh) release in the brain of freely moving rats exposed for 1 h during the day to a 2.45 GHz continuous wave radiofrequency field (RF) (2 or 4 mW/cm2) or exposed for 1 or 14 h during the night to a 800 MHz field modulated at 32 Hz (AM 200 mW/cm2). Measurements were performed by microdialysis using a membrane implanted through the upper CA1 region of the hippocampus. After irradiation with the 2.45 GHz RF, rats exposed at 2 mW/cm2 did not show a significant modification of Ach release, whereas those exposed at 4 mW/cm2 showed a significant 40% decrease in mean ACh release from hippocampus. This decrease was maximal at 5 h post exposure. Exposure to the 800 MHz RF for 1 h did not cause any significant effect, but exposure for 14 hrs induced a significant 43% decrease in ACh release during the period 11 p.m.–4 a.m. compared to control rats. In the control group we observed an increase of ACh release at the beginning of the night, which was linked to the waking period of rats. This normal increase was disturbed in rats exposed overnight to the 800 MHz RF. This work indicates that neurochemical modification of the hippocampal cholinergic system can be observed during and after an exposure to low intensity RF. Bioelectromagnetics 23:249–255, 2002. © 2002 Wiley‐Liss, Inc.
Modulatory effects of static magnetic fields on blood pressure in rabbits
Authors: Okano Hideyuki , Ohkubo Chiyoji 
Published: August 2002

AbstractAcute effects of locally applied static magnetic fields (SMF) on pharmacologically altered blood pressure (BP) in a central artery of the ear lobe of a conscious rabbit were evaluated. Hypotensive and vasodilator actions were induced by a Ca2+ channel blocker, nicardipine (NIC). Hypertensive and vasoconstrictive actions were induced by a nitric oxide synthase (NOS) inhibitor, Nω‐nitro‐L‐arginine methyl ester (L‐NAME). The hemodynamic changes in the artery exposed to SMF were measured continuously and analyzed by penetrating microphotoelectric plethysmography (MPPG). Concurrently, BP changes in a central artery contralateral to that of the exposed ear lobe were monitored. SMF intensity was 1 mT and the duration of exposure was 30 min. A total of 180 experimental trials were carried out in 34 healthy adult male rabbits weighing 2.6–3.8 kg. Six experimental procedures were chosen at random: (1) sham exposure without pharmacological treatment; (2) SMF exposure alone; (3) decreased BP induced by a single intravenous (iv) bolus injection of NIC (100 μM/kg) without SMF exposure; (4) decreased BP induced by injection of NIC with SMF exposure; (5) increased BP induced by a constant iv infusion of L‐NAME (10 mM/kg/h) without SMF exposure; (6) increased BP induced by infusion of L‐NAME with SMF exposure. The results demonstrated that SMF significantly reduced the vasodilatation with enhanced vasomotion and antagonized the reduction of BP via NIC‐blocked Ca2+ channels in vascular smooth muscle cells. In addition, SMF significantly attenuated the vasoconstriction and suppressed the elevation of BP via NOS inhibition in vascular endothelial cells and/or central nervous system neurons. These results suggest that these modulatory effects of SMF on BP might, in part, involve a feedback control system for alteration in NOS activity in conjunction with modulation of Ca2+ dynamics. Bioelectromagnetics 22:408–418, 2001. © 2001 Wiley‐Liss, Inc.
Cytogenetic damage in human lymphocytes following GMSK phase modulated microwave exposure
Authors: d'Ambrosio Guglielmo , Massa Rita , Scarfi Maria Rosaria , Zeni Olga 
Published: August 2002

AbstractThe present study investigated, using in vitro experiments on human lymphocytes, whether exposure to a microwave frequency used for mobile communication, either unmodulated or in presence of phase only modulation, can cause modification of cell proliferation kinetics and/or genotoxic effects, by evaluating the cytokinesis block proliferation index and the micronucleus frequency. In the GSM 1800 mobile communication systems the field is both phase (Gaussian minimum shift keying, GMSK) and amplitude (time domain multiple access, TDMA) modulated. The present study investigated only the effects of phase modulation, and no amplitude modulation was applied. Human peripheral blood cultures were exposed to 1.748 GHz, either continuous wave (CW) or phase only modulated wave (GMSK), for 15 min. The maximum specific absorption rate (∼5 W/kg) was higher than that occurring in the head of mobile phone users; however, no changes were found in cell proliferation kinetics after exposure to either CW or GMSK fields. As far as genotoxicity is concerned, the micronucleus frequency result was not affected by CW exposure; however, a statistically significant micronucleus effect was found following exposure to phase modulated field. These results would suggest a genotoxic power of the phase modulation per se. Bioelectromagnetics 23:7–13, 2002. © 2002 Wiley‐Liss, Inc.
The “tale” of UmuD and its role in SOS mutagenesis†
Authors: Gonzalez Martín , Woodgate Roger 
Published: August 2002

AbstractRecently, the Escherichia coli umuD and umuC genes have been shown to encode E. coli's fifth DNA polymerase, pol V (consisting of a heterotrimer of UmuD′2C). The main function of pol V appears to be the bypass of DNA lesions that would otherwise block replication by pols I–IV. This process is error‐prone and leads to a striking increase in mutations at sites of DNA damage. While the enzymatic properties of pol V are now only beginning to be fully appreciated, a great deal is known about how E. coli regulates the intracellular levels of the Umu proteins so that the lesion‐bypassing activity of pol V is available to help cells survive the deleterious consequences of DNA damage, yet keeps any unwarranted activity on undamaged templates to a minimum. Our review summarizes the multiple restrictions imposed upon pol V, so as to limit its activity in vivo and, in particular, highlights the pivotal role that the N‐terminal tail of UmuD plays in regulating SOS mutagenesis. BioEssays 24:141–148, 2002. Published 2002 Wiley Periodicals, Inc.
Intrinsic DNA bends: an organizer of local chromatin structure for transcription
Authors: Ohyama Takashi 
Published: August 2002

AbstractDNA with a curved trajectory of its helix axis is called bent DNA, or curved DNA. Interestingly, biologically important DNA regions often contain this structure, irrespective of the origin of DNA. In the last decade, considerable progress has been made in clarifying one role of bent DNA in prokaryotic transcription and its mechanism of action. However, the role of bent DNA in eukaryotic transcription remains unclear. Our recent study raises the possibility that bent DNA is implicated in the “functional packaging” of transcriptional regulatory regions into chromatin. In this article, I review recent progress in bent DNA research in eukaryotic transcription, and summarize the history of bent DNA research and several subjects relevant to this theme. Finally, I propose a hypothesis that bent DNA structures that mimic a negative supercoil, or have a right‐handed superhelical writhe, organize local chromatin infrastructure to help the very first interaction between cis‐acting DNA elements and activators that trigger transcription. BioEssays 23:708–715, 2001. © 2001 John Wiley & Sons, Inc.
Effect of aqueous cigarette smoke extract on the chemiluminescence kinetics of polymorphonuclear leukocytes and on their glycolytic and phagocytic activity
Authors: Zappacosta Bruno , Persichilli Silvia , Minucci Angelo , Stasio Enrico Di , Carlino Paola , Pagliari Gabriella , Giardina Bruno , Sole Pasquale De 
Published: August 2002

AbstractWater‐soluble extracts of cigarette smoke are easily formed in some body compartments, such as saliva or fluid lining alveolar spaces, and can act on both cellular and extracellular compartments. In this paper we have analysed the effect of aqueous smoke extract on some metabolic and functional aspects of polymorphonuclear leukocytes. In particular, the following cellular aspects were studied: chemiluminescence, glycolysis, membrane fluidity and microscopic interaction with zymosan particles. While chemiluminescence and glycolytic activity are highly inhibited, no effect of smoke extract on membrane fluidity was observed. Moreover, the response of luminol‐dependent chemiluminescence was significantly delayed, while that of lucigenin‐dependent chemiluminescence was anticipated. Furthermore, the phagocytic ability of neutrophils pretreated with aqueous smoke extract was also significantly hindered. All these results might indicate that the finely tuned activity of polymorphonuclear leukocytes is somehow hampered by the aqueous extract of cigarette smoke in a way which makes these cells less effective against bacteria and more noxious towards surrounding tissues. Copyright © 2001 John Wiley & Sons, Ltd.
Optical and IR absorption as probe of dynamics of heme proteins
Authors: Stavrov Solomon S. , Wright Wayne W. , Vanderkooi Jane M. , Fidy Judit , Kaposi Andras D. 
Published: August 2002

AbstractThe spectroscopy of horseradish peroxidase with and without the substrate analogue benzohydroxamic acid (BHA) was monitored in different solvents as a function of the temperature in the interval from 10 to 300 K. Thermal broadening of the Q(0,0) optical absorption band arises mainly from interaction of the electronic π → π transition with the heme vibrations. In contrast, the width of the IR absorption band of CO bound to heme is controlled by the coupling of the CO transition moment to the electric field of the protein matrix. The IR bandwidth of the substrate free enzyme in the glycerol/H2O solvent hardly changes in the glassy matrix and strongly increases upon heating above the glass transition. Heating of the same enzyme in the trehalose/H2O glass considerably broadens the band. The binding of the substrate strongly diminishes the temperature broadening of the CO band. This result is consistent with the view that the BHA strongly reduces the amplitude of vibrations of the heme pocket environment. Unusually strong thermal broadening of the CO band above the glass transition is interpreted to be caused by thermal population of a very flexible excited conformational substate. The thermal broadening of the same band in the trehalose glass is caused by an increase of the protein vibrational amplitude in each of the conformational substates, their population being independent of the temperature in the glassy matrix. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 255–258, 2002
Modeling of the structure in aqueous solution of the exopolysaccharide produced by Lactobacillus helveticus 766
Authors: Faber Elisabeth J. , van Kuik J. Albert , Kamerling Johannis P. , Vliegenthart Johannes F. G. 
Published: August 2002

AbstractA method is described for constructing a conformational model in water of a heteropolysaccharide built up from repeating units, and is applied to the exopolysaccharide produced by Lactobacillus helveticus 766. The molecular modeling method is based on energy minima, obtained from molecular mechanics calculations of each of the constituting disaccharide fragments of the repeating unit in vacuo, as starting points. Subsequently, adaptive umbrella sampling of the potential of mean force is applied to extract rotamer populations of glycosidic dihedral angles of oligosaccharide fragments in solution. From these analyses, the most probable conformations are constructed for the hexasaccharide‐repeating unit of the polysaccharide. After exploring the conformational space of each of the individual structures by molecular dynamics simulations, the different repeating unit conformations are used as building blocks for the generation of oligo‐ and polysaccharide models, by using a polysaccharide building program. The created models of the exopolysaccharide produced by L. helveticus 766 exhibit a flexible twisted secondary structure and tend to adopt a random coil conformation as tertiary structure. © 2002 John Wiley & Sons, Inc. Biopolymers 63: 66–76, 2002
Cell cycle‐dependent protein secretion by Saccharomyces cerevisiae
Authors: Frykman Scott , Srienc Friedrich 
Published: August 2002

AbstractSynchronized Saccharomyces cerevisiae cell populations were used to examine secretion rates of a heterologous protein as a function of cell cycle position. The synchronization procedure had a profound effect on the type and quality of data obtained. When cell synchrony was induced by cell cycle‐arresting drugs, a significant physiological perturbation of cells was observed that obscured representative secretion data. In contrast, synchronization with centrifugal elutriation resulted in synchronized first‐generation daughter cells with undetectable perturbation of the physiological state. The synchronized cells did not secrete significant amounts of protein until they reached cell division, suggesting that the secretion process in these cells is strongly cell cycle dependent. However, the maximum secretion rate of the synchronized culture (7–14 molecules/cell/second) was significantly lower than that of an asynchronous culture (29–51 molecules/cell/second). This result indicates that young daughter cells isolated in the synchronization process exhibit different protein secretion behavior than older mother cells that are absent in the synchronized cell population but present in the asynchronous culture. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 259–268, 2001.
Analysis of an engineered sulfate reduction pathway and cadmium precipitation on the cell surface
Authors: Wang Clifford L. , Clark Douglas S. , Keasling Jay D. 
Published: August 2002

AbstractWe previously have genetically engineered an aerobic sulfate reduction pathway in Escherichia coli for the generation of hydrogen sulfide and demonstrated the pathway's utility in the precipitation of cadmium. To engineer the pathway, the assimilatory sulfate reduction pathway was modified so that cysteine was overproduced. Excess cysteine was then converted by cysteine desulfhydrase to an abundance of hydrogen sulfide, which then reacted with aqueous cadmium to form cadmium sulfide. In this study, observations of various E. coli clones were combined with an analysis of kinetic and transport phenomena. This analysis revealed that cysteine production is the rate‐limiting step in the engineered pathway and provided an explanation for the phenomenon of cell surface precipitation. An analytical model showed that cadmium sulfide must form at the cell surface because the rate of cadmium sulfide formation is extremely fast and the rate of sulfide transport is relatively slow. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 285–291, 2001.