bluuebunny/crossref_metadata_2025_split huggingface dataset:
Virtual analogue simulation of semiconductor lasers and photon transport transistors
Authors: Cheung W. N. 
Published: August 2002

AbstractA behavioural modelling method is described for investigating various characteristics of single‐mode semiconductor lasers. The method is based on the rate equations associated with the device, and simulation is carried out using circuit analogues implemented on the software platform of PSpice. As illustrations of the method, simulation results including light‐current characteristics, charge number clamping, modulation response and transient behaviour of a typical laser diode are given. The virtual analogue simulation method has been applied to predict the behaviour of a class of opto‐electronic devices called photon transport transistors formed with appropriate current feedback to the laser diode. The results indicate that the PTT has an increased damping and a higher modulation sensitivity brought about by its current gain. In the use for driving laser diodes the PTT may result in improved pulse modulation characteristics. Copyright © 2001 John Wiley & Sons, Ltd.
ST8Sia IV mRNA corresponds with the biosynthesis of α2,8sialyl polymers but not oligomers in rat oligodendrocytes
Authors: Stoykova Lidia I. , Beesley Jacqueline S. , Grinspan Judith B. , Glick Mary Catherine 
Published: August 2002

AbstractAs oligodendrocytes mature they progress through a series of distinct differentiation steps characterized by the expression of specific markers. One such marker, polysialic acid found on the neural cell adhesion molecule (NCAM), is detected by antibodies and is present on progenitor oligodendrocytes, but is not detected to the same extent on mature oligodendrocytes. Two closely related polysialyltransferases, ST8Sia II (STX) and ST8Sia IV (PST) have been cloned previously and shown to synthesize polysialic acid on NCAM and other glycoproteins. To determine whether or not polyα2,8sialyltransferases are downregulated during the differentiation of oligodendrocytes, the enzyme activity and expression of ST8Sia II and ST8Sia IV mRNA at two stages of maturation in JS12/1 and JS3/16 oligodendrocytes were examined. Differentiation in both oligodendroglial cell lines was accompanied by more than a 50% reduction in the biosynthesis of polymers of α2,8sialic acid when fetuin was used as substrate. Most interestingly, extracts of JS12/1 mature cells synthesized 60% more short oligomers of α2,8sialic acid than the progenitor cells, whereas JS3/16 mature cells synthesized barely detectable amounts of the short oligomers. Transcripts for ST8Sia IV mRNA were present in both JS12/1 and JS3/16 and were reduced when the biosynthesis was markedly reduced. In contrast ST8Sia II mRNA was barely detectable in JS3/16 cells and although detectable in JS12/1 cells, there was no clear modulation with maturation. These results were supported by the examination of the brains of rats from embryonic to Day 21 ages. The enzyme activity and mRNA experiments show that polyα2,8sialyltransferase itself is down regulated to cause the reduction in sialyl polymers on mature oligodendrocytes. Moreover, ST8Sia IV is responsible for the polysialylation of NCAM in oligodendrocytes. J. Neurosci. Res. 66:497–505, 2001. © 2001 Wiley‐Liss, Inc.
Developmental changes in the protein composition of sphingolipid‐ and cholesterol‐enriched membrane domains of rat cerebellar granule cells
Authors: Palestini Paola , Botto Laura , Guzzi Francesca , Calvi Chiara , Ravasi Daniela , Masserini Massimo , Pitto Marina 
Published: August 2002

AbstractThe biological role of cell membrane domains has been investigated in a number of eukariotic cells, but less attention has been paid to the neuron. In the present investigation, we assessed the changes in lipid and protein composition of detergent‐resistant membrane fractions prepared from cultured rat cerebellar granule cells, during differentiation and maturation in vitro. At any stage of the cell life, low‐density, detergent‐resistant fractions, characterised by the specific presence of prion protein, were enriched in glycolipids, cholesterol, and sphingomyelin. The enrichment in sphingomyelin was developmentally regulated, increasing continuously during cell differentiation and maturation. Concerning proteins, domains were enriched in Fyn and TAG‐1, which present exclusively within this fraction at any stage of cell culture, and in GAP‐43, mainly during the differentiation stage. On the other side, proteins affecting signal transduction and cytoskeleton‐related proteins (heterotrimeric G‐proteins, protein kinase C, MARCKS, tubulin), were not enriched within detergent‐resistant fractions during cell differentiation, but were recovered within this fraction in mature neurons. These results indicate that during different cellular life stages, specific proteins are recruited within detergent‐resistant membrane domains of the neuron and suggest their involvement in specific physiological phenomena (differentiation, maturation and/or aging). © 2002 Wiley‐Liss, Inc.
Plasma membrane calcium ATPase plays a role in reducing Ca2+‐mediated cytotoxicity in PC12 cells
Authors: Garcia Michael L. , Usachev Yuriy M. , Thayer Stanley A. , Strehler Emanuel E. , Windebank Anthony J. 
Published: August 2002

AbstractIn many cell types, cell death induced by a variety of insults is accompanied by an increase in intracellular calcium. The Ca2+ homeostatic mechanisms affected by such insults, however, have not been fully determined. Recent evidence indicates that kainic acid‐induced seizures alter plasma membrane calcium ATPase mRNA expression within vulnerable hippocampal cell populations before the onset of cell death. We examined the effects of altering plasma membrane calcium ATPase expression on cell vulnerability in rat pheochromocytoma 12 cells. Pheochromocytoma 12 cells are vulnerable to Ca2+ overload induced by the Ca2+ ionophore A23187. Reverse transcriptase‐PCR and Western blot data indicated that plasma membrane calcium ATPase isoform 4b constitutes a major calcium pump isoform in the pheochromocytoma 12 cells. Therefore, permanently transfected pheochromocytoma 12‐derived cell lines were established that either over‐expressed plasma membrane calcium ATPase isoform 4b, or suppressed the expression of the endogenous plasma membrane calcium ATPase isoform 4. Over‐expressing clones were less vulnerable to Ca2+‐mediated cell death induced by A23187 whereas “antisense” clones were considerably more susceptible. These data indicate that regulation of plasma membrane calcium ATPase expression may be critical to cellular survival when cells are exposed to pathological increases in intracellular calcium. J. Neurosci. Res. 64:661–669, 2001. © 2001 Wiley‐Liss, Inc.
Juxtaposition of descriptions of Raman and resonance Raman scattering by classical and mixed quantum– classical theories
Authors: Morozov V. A. , Dubina Yu. M. 
Published: August 2002

AbstractRaman scattering (RS) is described by a classical model for molecular electronic and nuclear subsystems coupled by one of the simplest cubic non‐linear couplings. The corresponding system of classical non‐linear equations for the motion of electrons and nuclei of a molecule in an electric field of low‐intensity incident light is compared with the system of equations for a mixed quantum– classical model that describes the quantum dynamics of a two‐state electronic molecular subsystem and classical dynamics of a nuclear subsystem of the molecule. Here the classical dynamics are defined by the Born– Oppenheimer quadratic potential with consideration of the equilibrium position shift of the nuclei when an electronic subsystem transition from the basic state to the excited state occurs. A simple relationship, for which non‐resonance RS line intensities for both models of molecule are nearly equal, was established between the shift and the parameter characterizing the effectiveness of the coupling of electronic and nuclear oscillators in the classical molecule's model. Capabilities for comparing the description of resonance Raman scattering by the considered models and the question of the occurrence of a background in resonance RS spectra due to non‐linear coupling between electronic and nuclear subsystems of the molecule are also examined. Copyright © 2001 John Wiley & Sons, Ltd.
Computed vibrational wavenumbers in ammonium fluoride crystals
Authors: Alavi A. , Lynden‐Bell R. M. , Brown R. J. C. 
Published: August 2002

AbstractThe vibrational wavenumbers of crystalline ammonium fluoride were calculated using the density functional method. The results support the experimental conclusions that the symmetric stretching mode in NH4F lies at a higher wavenumber than the asymmetric stretch, that these wavenumbers are reversed in ND4F and that the librational wavenumbers lie at ∼560 cm–1. Copyright © 2001 John Wiley & Sons, Ltd.
Vibrational spectra of barium formate crystal
Authors: Liu Jianjun , Wang Yufang , Lan Guoxiang , Zheng Jimin 
Published: August 2002

AbstractThe Raman spectra of barium formate were investigated at room temperature and liquid nitrogen temperature and the infrared absorption and reflection spectra at room temperature. The presence of two crystallographically non‐equivalent sets of formate ions in the lattice results in the doubling of the internal modes in the vibrational spectra. The observed high‐wavenumber vibrational bands are assigned to the internal vibrations of formate ions. Copyright © 2001 John Wiley & Sons, Ltd.
Internet firms: what strategic changes have to be managed?
Authors: Barrow Colin 
Published: August 2002

Abstract

Considerable faith has been placed by investors in the economic wealth to be created by the application of Internet technology. The scramble for a place on the Internet bandwagon has diverted risk capital from other types of industry and seduced key staff to leave old economy jobs in droves to join dot.com start ups at lower salary levels.

This article seeks to demonstrate that quoted Internet firms are for the most part seriously overvalued and that this will impose the need for large‐scale change early in a firm's life.

It explores the strength and robustness of the strategies that underpin Internet valuations and what major areas of change are likely to be faced.

The article should be seen as work in progress. Research into Internet firms is still in its infancy. Few Internet firms have gone through their whole life cycle, so evaluating success and failure is inevitably tentative. However, some patterns are emerging which indicate areas worthy of future exploration. This paper seeks to signpost some of those areas.

Copyright © 2001 John Wiley & Sons, Ltd.
Effects of gas composition in modified atmosphere packaging on the meat quality of Spanish Manchega lamb
Authors: Vergara Herminia , Gallego Laureano 
Published: August 2002

AbstractThe effects of four types of packaging atmosphere, each with a different gas composition (20–80% CO2), on the meat quality of Spanish Manchega lamb were examined in order to suggest a gas composition for optimal preservation. Meat quality was assessed by pH, colour (L*,a* and b* values), water‐holding capacity (WHC), cooking loss (CL) and shear force (SF). Gas composition affected all parameters except L* and SF. The pH values decreased significantly in samples packed with 80% CO2 but remained constant in the other groups. The b* values were lower in samples packed without O2 than in the other groups and increased with time. However, the a* values decreased in all groups with time. Samples packed in low‐CO2 atmosphere tended to lose more water (ie to have less WHC and show more CL). The SF values decreased with time, and similar values of this parameter were observed for all treatments.© 2001 Society of Chemical Industry
Ex vivo sentinel lymph node biopsy in colorectal cancer: A feasibility study
Authors: Fitzgerald T.L. , Khalifa M.A. , Al Zahrani M. , Law C.H.L. , Smith A.J. 
Published: August 2002

AbstractBackground and ObjectivesSentinel lymph node (SLN) biopsy may improve staging of colorectal cancer. We tested the feasibility of ex vivo SLN dissection.Materials and MethodsPatients undergoing resection of a primary colorectal cancer were included in this study. SLN identification involved ex vivo injection of 1 cc isosulfan blue dye subserosally in the colon or submucosally in the rectum on a separate field. SLNs were cut at 2 mm intervals. Three hematoxylin and eosin‐stained (HE) sections were prepared in addition to a middle level for cytokeratin immunostaining.ResultsTwenty‐six patients with varying tumor location and stage were enrolled and the SLN was identified in 88% (23/26) cases. Three failures occurred in patients with rectal cancer. The average number of SLN harvested was 2.5. The status of the nodal basin was accurately predicted in 91% (21/23) of patients. Two false negative sentinel lymph nodes were harvested in 2 of 3 patients with stage III/IV colorectal cancer. The SLN upstaged 2 patients as a result of HE stained step sections (n = 1) and immunostaining (n = 1).ConclusionsThis data suggests that ex vivo SLN biopsy is feasible in colorectal cancer. Although ex vivo SLN biopsy does not alter the lymphatic dissection, it may upstage a subset of patients. The ex vivo technique may be less applicable in rectal cancer and false negative results may occur. J. Surg. Oncol. 2002;80:27–32. © 2002 Wiley‐Liss, Inc.
Photodecomposition of iodopentanes in air: Product distributions from the self‐reactions of n‐pentyl peroxyl radicals
Authors: Heimann Gerald , Benkelberg Heinz‐Jürgen , Böge Olaf , Warneck Peter 
Published: August 2002

AbstractProduct distributions from the 254‐nm photooxidation of the three iodopentane isomers were explored as a technique for studying the self‐reactions of individual pentyl peroxyl radicals (in air at ambient temperature and pressure). Pentanols and the associated carbonyl compounds (pentanal or pentanones) were major products as expected. Other major products resulted from the isomerization of pentan‐1‐oxyl and pentan‐2‐oxyl radicals, but their nature could not be identified. Minor products were alcohols and carbonyl compounds arising from the decomposition of pentoxyl radicals. Diols and mixed hydroxycarbonyl compounds from cross‐combination reactions were essentially absent, in contrast to expectation. The observed product distributions were evaluated to derive branching ratios for the radical‐preserving pathways of the self‐reactions, 0.42 ±0.17, 0.46 ± 0.10, 0.39 ± 0.08, for pentan‐1‐yl peroxyl, pentan‐2‐yl peroxyl, and pentan‐3‐yl peroxyl, respectively. Rate coefficients derived for the decomposition of the corresponding pentoxyl radicals, relative to their reaction with oxygen, are (5.1 ± 0.5) × 1018, (1.0 ± 0.2) × 1018, and (3.2 ± 0.3) × 1018 molecule cm−3, respectively. Rate constants for the isomerization of pentan‐1‐oxyl and pentan‐2‐oxyl were estimated from the contributions of isomerization products to the total amounts of products as (4.0 ± 1.1) × 105 s−1 and (1.0 ± 2.0) × 105 s−1, respectively. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 34: 126–138, 2002
Kinetics of liquid phase synthesis of ethyl tert‐butyl ether from tert‐butyl alcohol and ethanol catalyzed by β‐zeolite supported on monolith
Authors: Assabumrungrat S. , Kiatkittipong W. , Sevitoon N. , Praserthdam P. , Goto S. 
Published: August 2002

AbstractThis paper compared the performance of β‐zeolite and Amberlyst‐15 catalysts on a liquid phase synthesis of ethyl tert‐butyl ether (ETBE) from ethanol (EtOH) and tert‐butyl alcohol (TBA) β‐Zeolite was synthesized and deposited on monolith support. Its structure was confirmed by an XRD measurement and its composition was analyzed by an XRF measurement. It was found that even though the catalytic activity of β‐zeolite was lower than that of Amberlyst‐15, the selectivity of ETBE was much higher than that of Amberlyst‐15, resulting in almost the same level of ETBE yield. The dehydration of TBA to isobutene (IB) was the major side reaction. The kinetic study of the reaction catalyzed by β‐zeolite supported on monolith was carried out by using a semibatch reactor. The effect of external mass transfer was investigated by varying stirring speeds. The activity‐based rate expressions were developed taking into account of water inhibition. Three temperature levels of 323, 333, and 343 K were performed in the study to obtain the parameters in the Arrhenius's equation and the Van't Hoff's equation. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 292–299, 2002
Modeling regional electric power markets and market power
Authors: Cope III Robert F. , Dismukes David E. , Cope Rachelle F. 
Published: August 2002

AbstractThis paper develops a nonlinear, mathematical programming model for estimating production decisions in an open access, regional power market. Our approach allows one to estimate competitive power market equilibrium prices, which in turn offers empirical conclusions about marginal generation facilities, transmission interconnection congestion, and most importantly, load pockets and market power. Sensitivity analyses are conducted by subjecting the model to changes in production costs, peak hour demand, power imports, and transmission interconnection price assumptions. We then consider the issue of a firm's ability to exercise market power and the implications it may have on regional equilibrium power prices. The Louisiana power market is used as a case study for our work. Copyright © 2001 John Wiley & Sons, Ltd.
Validation for tremor quantification of an electromagnetic tracking device
Authors: O'Suilleabhain Padraig E. , Dewey Richard B. 
Published: August 2002

AbstractAn electromagnetic tracking system was used to record arm motion in subjects with Parkinson's disease (n = 23), essential tremor (n = 28) or without neurological disease (n = 4). Tremor magnitude was calculated by averaging the three‐dimensional displacement of individual tremor bursts. Tremor magnitude calculated in this manner was quite closely correlated with a clinician's estimate (r = 0.88 and 0.86 for Parkinsonian and essential tremors, respectively) and was reproducible (r = 0.93 for repeated recordings). The accuracy of the device and algorithm was confirmed by mechanically generating oscillations of known magnitudes and frequencies. This device is adaptable for quantifying different types of tremors and its accuracy is easy to verify. Because position rather than acceleration is tracked, tremor amplitude can be stated in readily comprehensible units. © 2001 Movement Disorder Society.
Permanent cerebellar toxicity of cytosine arabinoside (Ara C) in a young woman
Authors: Friedman Joseph H. , Shetty Neetha 
Published: August 2002

AbstractThis report provides the first videotape example of a patient with permanent cerebellar ataxia from high dose cytosine arabinoside. This case was unusual in that the patient was young, the effects are seemingly permanent and severe, and corticospinal tract damage also occurred. Early recognition to stop drug administration remains the only method to reduce risk.
Familial paroxysmal exercise‐induced dyskinesia, epilepsy, and mental retardation in a family with autosomal dominant inheritance
Authors: Perniola T. , Margari L. , de Iaco M.G. , Presicci A. , Ventura P. , Ferrannini E. , Illiceto G. 
Published: August 2002

AbstractOnly few sporadic and familial cases of paroxysmal exercise‐induced dyskinesia (PED) have been described in literature. PED associated with familial epilepsy has been rarely reported. We describe a family in which six members in different generations were affected by a long‐lasting PED, with childhood onset in five cases. Fasting and stress were also precipitating factors. All the subjects, moreover, showed epileptic seizures during childhood and adolescence. In addition, in all cases a condition of mild mental retardation was also documented, associated in some cases, with irritable and impulsive behaviour. Clinical, neurophysiological, neuroimaging and neuropsychological findings were reported. The homogeneous recurrence of this particular clinical picture in members of three generations emphasised a common genetic basis. In our patients, PED is transmitted as an autosomal dominant trait, with age‐dependent penetrance, without evidence of genetic anticipation. The neurophysiological findings suggest a condition of hyperexcitability in the muscular and brain membrane, due to a ion channels disorder. © 2001 Movement Disorder Society.
Neurostimulation of the ventral intermediate thalamic nucleus in inherited myoclonus‐dystonia Syndrome
Authors: Trottenberg Thomas , Meissner Wassilios , Arnold Guy , Einhaupl Karl‐Max , Kupsch Andreas , Kabus Christian , Funk Thomas 
Published: August 2002

AbstractWe report on the effects of bilateral neurostimulation of the ventral intermediate thalamic nucleus (VIM) in a patient with medically intractable and progressing inherited myoclonus dystonia syndrome (IMDS). Postoperatively, the patient improved by approximately 80% on the modified version of a myoclonus score without any significant change in the dystonic symptoms. This suggests that neurostimulation of the VIM may be an effective treatment for myoclonus in pharmacologically intractable IMDS. © 2001 Movement Disorder Society.
Delayed penile replantation after prolonged warm ischemia
Authors: Mosahebi Afshin , Butterworth Mark , Knight Ross , Berger Leslie , Kaisary Amir , Butler Peter E.M. 
Published: August 2002

AbstractWe report a case of microsurgical replantation of traumatic self‐amputation of penis after prolonged warm ischemia as a result of delayed presentation. At 12 weeks postoperative follow‐up evaluation, the patient exhibited good urinary flow, spontaneous erection, and a normal response to pharmacological stimulation. © 2001 Wiley‐Liss, Inc. MICROSURGERY 21:52–54 2001
Non‐classical boundary value problems of elastostatics and hydrostatics on Lipschitz domains
Authors: Mitrea Dorina 
Published: August 2002

AbstractThe main goal of this paper is to undertake a systematic study of the Stokes and Lamé systems with non‐classical boundary conditions in arbitrary Lipschitz subdomains of R3. These include prescribing 〈n, u〉 in concert with n×curl u on the boundary of the domain in question. Copyright © 2001 John Wiley & Sons, Ltd.
Design of optical filters using uniaxial dielectric gratings for arbitrary light polarization
Authors: Costa João Crisóstomo Weyl A. , Giarola Attílio José , Lisboa da Silva Nildsen Fernando 
Published: August 2002

AbstractThe main objective of this paper is to show that, with the use of a one‐dimensional grating, having uniaxial dielectric anisotropy, it is possible to change the frequency of the maximum reflection transmission peak of an incident wave with a TM polarization, while maintaining the corresponding frequency of an incident TE wave fixed, without the need to change the grating geometry. This will allow the design of optical filters that are independent of the incident light polarization. A rigorous modal theory is used, such that the fields propagating in the various regions of the structure are represented as a summation of infinite models. It is shown that polarization independence is achieved by conveniently choosing the value of the grating dielectric ratio anisotropy ratio εxx/εzz. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 86–89, 2001.
Determining the RF resistance and Q‐factor of air‐core inductors
Authors: Gross Shay , Weller Thomas 
Published: August 2002

AbstractAir‐core inductors are large‐body, low‐loss components that find frequent use in circuits such as RF power amplifier matching networks. The physical attributes of the inductors make loss characterization using standard commercial instruments (e.g., impedance analyzers or resonant coaxial lines) problematic. In this paper, a resistance and quality factor extraction technique based on low‐impedance microstrip test fixtures is demonstrated at frequencies near 800 MHz. It is shown that an inductor resistance on the order of 0.1–1 Ω can be accurately determined. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 89–93, 2001.