bluuebunny/crossref_metadata_2025 huggingface dataset:
The antioxidant (−)-epigallocatechin-3-gallate inhibits activated hepatic stellate cell growth and suppresses acetaldehyde-induced gene expression
Authors: CHEN Anping , ZHANG Li , XU Jianye , TANG Jun
Published: February 2003

Activated hepatic stellate cells (HSC) are the primary source of excessive production of extracellular matrix during liver fibrogenesis. Although the underlying mechanisms remain incompletely understood, it is widely accepted that oxidative stress plays a critical role in liver fibrogenesis. Suppression of HSC growth and activation, as well as induction of apoptosis, have been proposed as therapeutic strategies for treatment and prevention of this disease. In the present report, we elucidated, for the first time, effects of the antioxidant (—)-epigallocatechin-3-gallate (EGCG), a major (and the most active) component of green tea extracts, on cultured HSC growth and activation. Our results revealed that EGCG significantly inhibited cultured HSC growth by inducing cell cycle arrest and apoptosis in a dose- and time-dependent manner. In addition, EGCG markedly suppressed the activation of cultured HSC as demonstrated by blocking transforming growth factor-β signal transduction and by inhibiting the expression of α1(I) collagen, fibronectin and α-smooth muscle actin genes induced by acetaldehyde, the most active metabolite of ethanol. Furthermore, EGCG reacted differently in the inhibition of nuclear factor-κB activity between cultured HSC with or without acetaldehyde stimulation. Taken together, our results indicated that EGCG was a novel and effective inhibitor for activated HSC growth and activation in vitro. Further studies are necessary to evaluate the effect of this polyphenol in prevention of quiescent HSC activation in vivo, and to further elucidate the underlying mechanisms.
Superoxide-dependent consumption of nitric oxide in biological media may confound in vitro experiments
Authors: KEYNES Robert G. , GRIFFITHS Charmaine , GARTHWAITE John
Published: February 2003

NO functions ubiquitously as a biological messenger but has also been implicated in various pathologies, a role supported by many reports that exogenous or endogenous NO can kill cells in tissue culture. In the course of experiments aimed at examining the toxicity of exogenous NO towards cultured cells, we found that most of the NO delivered using a NONOate (diazeniumdiolate) donor was removed by reaction with the tissue-culture medium. Two NO-consuming ingredients were identified: Hepes buffer and, under laboratory lighting, the vitamin riboflavin. In each case, the loss of NO was reversed by the addition of superoxide dismutase. The effect of Hepes was observed over a range of NONOate concentrations (producing up to 1μM NO). Furthermore, from measurements of soluble guanylate cyclase activity, Hepes-dependent NO consumption remained significant at the low nanomolar NO concentrations relevant to physiological NO signalling. The combination of Hepes and riboflavin (in the light) acted synergistically to the extent that, instead of a steady-state concentration of about 1μM being generated, NO was undetectable (<10nM). Again, the consumption could be inhibited by superoxide dismutase. A scheme is proposed whereby a ‘vicious cycle’ of superoxide radical (O2•-) formation occurs as a result of oxidation of Hepes to its radical species, fuelled by the subsequent reaction of O2•- with NO to form peroxynitrite (ONOO-). The inadvertent production of ONOO- and other reactive species in biological media, or the associated loss of NO, may contribute to the adverse effects, or otherwise, of NO in vitro.
Bax oligomerization in mitochondrial membranes requires tBid (caspase-8-cleaved Bid) and a mitochondrial protein
Authors: ROUCOU Xavier , MONTESSUIT Sylvie , ANTONSSON Bruno , MARTINOU Jean-Claude
Published: February 2003

In response to various apoptotic stimuli, Bax, a pro-apoptotic member of the Bcl-2 family, is oligomerized and permeabilizes the mitochondrial outer membrane to apoptogenic factors, including cytochrome c. Bax oligomerization can also be induced by incubating isolated mitochondria containing endogenous Bax with recombinant tBid (caspase-8-cleaved Bid) in vitro. The mechanism by which Bax oligomerizes under these conditions is still unknown. To address this question, recombinant human full-length Bax was purified as a monomeric protein. Bax failed to oligomerize spontaneously in isolated mitochondria or in liposomes composed of either cardiolipin or lipids extracted from mitochondria. However, in the presence of tBid, the protein formed large complexes in mitochondrial membranes and induced the release of cytochrome c. tBid also induced Bax oligomerization in isolated mitochondrial outer membranes, but not in other membranes, such as plasma membranes or microsomes. Moreover, tBid-induced Bax oligomerization was inhibited when mitochondria were pretreated with protease K. The presence of the voltage-dependent anion channel was not required either for Bax oligomerization or for Bax-induced cytochrome c release. Finally, Bax oligomerization was reconstituted in proteoliposomes made from mitochondrial membrane proteins. These findings imply that tBid is necessary but not sufficient for Bax oligomerization; a mitochondrial protein is also required.
Solution structure and topology of the N-terminal membrane anchor domain of a microsomal cytochrome P450: prostaglandin I2 synthase
Authors: RUAN Ke-He , SO Shui-Ping , ZHENG Weida , WU Jiaxin , LI Dawei , KUNG Jennifer
Published: February 2003

The three-dimensional structure of a synthetic peptide corresponding to the N-terminal membrane anchor domain (residues 1—25) of prostaglandin I2 synthase (also known as cytochrome P450 8A1), an eicosanoid-synthesizing microsomal cytochrome P450, has been determined by two-dimensional 1H NMR spectroscopy in trifluoroethanol and dodecylphosphocholine which mimic the hydrophobic membrane environment. A combination of two-dimensional NMR experiments, including NOESY, TOCSY and double-quantum-filtered COSY, was used to obtain complete 1H NMR assignments for the peptide. Using the NOE data obtained from the assignments and simulated annealing calculations, the N-terminal membrane domain reveals a bent-shaped structure comprised of an initial helix (residues 3—11), followed by a turn (residues 12—16) and a further atypical helix (residues 17—23). The hydrophobic side chains of the helix and turn segments (residues 1—20) are proposed to interact with the hydrocarbon interior of the phospholipid bilayer of the endoplasmic reticulum (ER) membrane. The hydrophilic side chains of residues 21—25 (Arg-Arg-Arg-Thr-Arg) point away from the hydrophobic residues 1—20 and are expected to be exposed to the aqueous environment on the cytoplasmic side of the ER membrane. The distance between residues 1 and 20 is approx. 20Å (1Å = 0.1nm), less than the thickness of a lipid bilayer. This indicates that the N-terminal membrane anchor domain of prostaglandin I2 synthase does not penetrate the ER membrane.
Monitoring of apoptosis of HL60 cells by Fourier-transform infrared spectroscopy
Authors: GASPARRI Fabio , MUZIO Marta
Published: February 2003

Fourier-transform infrared (FTIR) spectroscopy is a vibrational technique that gives information on the chemical composition of a sample, providing a ‘molecular fingerprint’ of it. It is a powerful approach to study intact cells. The aim of the present study was to analyse and quantify apoptotic cells by using a FTIR approach based on attenuated total reflection (ATR). We incubated human HL60 leukaemic cells with camptothecin, a cytotoxic drug, and monitored apoptosis induction over a period of time. Several ATR—FTIR spectral changes occurred during the apoptotic process. In particular, we observed that the apoptotic index was inversely correlated with the spectral area in the region 1200—900cm-1, assigned to the absorption of nucleic acids. We therefore propose that ATR—FTIR spectral features may be used as a diagnostic marker of apoptotic cells.
Effects of osmolarity, ions and compatible osmolytes on cell-free protein synthesis
Authors: BRIGOTTI Maurizio , PETRONINI Pier Giorgio , CARNICELLI Domenica , ALFIERI Roberta R. , BONELLI Mara A. , BORGHETTI Angelo F. , WHEELER Kenneth P.
Published: February 2003

To mimic what might happen in cells exposed to hypertonicity, the effects of increased osmolarity and ionic strength on cell-free protein synthesis have been examined. Translation of globin mRNA by rabbit reticulocyte lysate decreased by 30—60% when osmolality was increased from 0.35 to 0.53osmol/kg of water by the addition of NaCl, KCl, CH3CO2Na or CH3CO2K. In contrast, equivalent additions of the compatible osmolytes betaine or myo-inositol caused a 40—50% increase in the rate of translation, whereas amino acids (50—135mM) that are transported via system A had no significant effect. Addition of 75mM KCl caused a dramatic fall in the amount of the 43S pre-initiation complex, whereas it was totally preserved when osmolarity was similarly increased by the addition of 150mM betaine. The formation of a non-enzymic initiation complex between rabbit [3H]Phe-tRNA, poly(U) and the 80S ribosomes was unaffected by the addition of 75mM NaCl or KCl, but translation of the complex decreased by 70%. Density-gradient centrifugation of reticulocyte extracts translating endogenous mRNA revealed that addition of 150mM betaine had no effect, whereas addition of 75mM KCl caused a marked decrease in the polysome peak, concomitant with an increase in the proportion of 80S ribosomes and ribosomal subunits, even when elongation was inhibited with fragment A of diphtheria toxin. These results are consistent with the notion that both initiation and elongation are inhibited by unusually high concentrations of inorganic ions, but not by the compatible osmolytes betaine or myo-inositol.
Disruption of the SHM2 gene, encoding one of two serine hydroxymethyltransferase isoenzymes, reduces the flux from glycine to serine in Ashbya gossypii
Authors: SCHLÜPEN Christina , SANTOS Maria A. , WEBER Ulrike , GRAAF Albert de , REVUELTA José L. , STAHMANN K.-Peter
Published: February 2003

Riboflavin overproduction in the ascomycete Ashbya gossypii is limited by glycine, a precursor of purine biosynthesis, and therefore an indicator of glycine metabolism. Disruption of the SHM2 gene, encoding a serine hydroxymethyltransferase, resulted in a significant increase in riboflavin productivity. Determination of the enzyme's specific activity revealed a reduction from 3m-units/mg of protein to 0.5m-unit/mg protein. The remaining activity was due to an isoenzyme encoded by SHM1, which is probably mitochondrial. A hypothesis proposed to account for the enhanced riboflavin overproduction of SHM2-disrupted mutants was that the flux from glycine to serine was reduced, thus leading to an elevated supply with the riboflavin precursor glycine. Evidence for the correctness of that hypothesis was obtained from 13C-labelling experiments. When 500μM 99% [1-13C]threonine was fed, more than 50% of the label was detected in C-1 of glycine resulting from threonine aldolase activity. More than 30% labelling determined in C-1 of serine can be explained by serine synthesis via serine hydroxymethyltransferase. Knockout of SHM1 had no detectable effect on serine labelling, but disruption of SHM2 led to a decrease in serine (2—5%) and an increase in glycine (59—67%) labelling, indicating a changed carbon flux.
Protein kinase B/Akt is essential for the insulin- but not progesterone-stimulated resumption of meiosis in Xenopus oocytes
Authors: ANDERSEN Carsten B. , SAKAUE Hiroshi , NEDACHI Taku , KOVACINA Kristina S. , CLAYBERGER Carol , CONTI Marco , ROTH Richard A.
Published: February 2003

In the present study, we have characterized the Xenopus Akt expressed in oocytes from the African clawed frog Xenopus laevis and tested whether its activity is required for the insulin- and progesterone-stimulated resumption of meiosis. A cDNA encoding the Xenopus Akt was isolated and sequenced, and its expression in the Xenopus oocyte was confirmed by reverse transcription PCR and Northern blotting. Using phosphospecific antibodies and enzyme assays, a large and rapid activation of the Xenopus Akt was observed upon insulin stimulation of the oocytes. In contrast, progesterone caused a modest activation of this kinase with a slower time course. To test whether the activation of Akt was required in the stimulation of the resumption of meiosis, we have utilized two independent approaches: a functional dominant negative Akt mutant and an inhibitory monoclonal antibody. Both the mutant Akt, as well as the inhibitory monoclonal antibody, completely blocked the insulin-stimulated resumption of meiosis. In contrast, both treatments only partially inhibited (by approx. 30%) the progesterone-stimulated resumption of meiosis when submaximal doses of this hormone were utilized. These data demonstrate a crucial role for Akt in the insulin-stimulated cell cycle progression of Xenopus oocytes, whereas Akt may have an ancillary function in progesterone signalling.
Characterization of the Aalpha and Abeta subunit isoforms of protein phosphatase 2A: differences in expression, subunit interaction, and evolution
Authors: ZHOU Jin , PHAM Huong T. , RUEDIGER Ralf , WALTER Gernot
Published: February 2003

Protein phosphatase 2A (PP2A) is very versatile owing to a large number of regulatory subunits and its ability to interact with numerous other proteins. The regulatory A subunit exists as two closely related isoforms designated Aα and Aβ. Mutations have been found in both isoforms in a variety of human cancers. Although Aα has been intensely studied, little is known about Aβ. We generated Aβ-specific antibodies and determined the cell cycle expression, subcellular distribution, and metabolic stability of Aβ in comparison with Aα. Both forms were expressed at constant levels throughout the cell cycle, but Aα was expressed at a much higher level than Aβ. Both forms were found predominantly in the cytoplasm, and both had a half-life of approx. 10h. However, Aα and Aβ differed substantially in their expression patterns in normal tissues and in tumour cell lines. Whereas Aα was expressed at similarly high levels in all tissues and cell lines, Aβ expression varied greatly. In addition, in vivo studies with epitope-tagged Aα and Aβ subunits demonstrated that Aβ is a markedly weaker binder of regulatory B and catalytic C subunits than Aα. Construction of phylogenetic trees revealed that the conservation of Aα during the evolution of mammals is extraordinarily high in comparison with both Aβ and cytochrome c, suggesting that Aα is involved in more protein—protein interactions than Aβ. We also measured the binding of polyoma virus middle tumour antigen and simian virus 40 (SV40) small tumour antigen to Aα and Aβ. Whereas both isoforms bound polyoma virus middle tumour antigen equally well, only Aα bound SV40 small tumour antigen.
Glucagon-like peptide-1 mobilizes intracellular Ca2+ and stimulates mitochondrial ATP synthesis in pancreatic MIN6 beta-cells
Authors: TSUBOI Takashi , SILVA XAVIER Gabriela da , HOLZ George G. , JOUAVILLE Laurence S. , THOMAS Andrew P. , RUTTER Guy A.
Published: February 2003

Glucagon-like peptide-1 (GLP-1) is a potent regulator of glucose-stimulated insulin secretion whose mechanisms of action are only partly understood. In the present paper, we show that at low (3mM) glucose concentrations, GLP-1 increases the free intramitochondrial concentrations of both Ca2+ ([Ca2+]m), and ATP ([ATP]m) in clonal MIN6 β-cells. Suggesting that cAMP-mediated release of Ca2+ from intracellular stores is responsible for these effects, increases in [ATP]m that were induced by GLP-1 were completely blocked by the Rp isomer of adenosine-3′,5′-cyclic monophosphothioate (Rp-cAMPS), or by chelation of intracellular Ca2+. Furthermore, inhibition of Ins(1,4,5)P3 (IP3) receptors with xestospongin C, or application of ryanodine, partially inhibited GLP-1-induced [ATP]m increases, and the simultaneous blockade of both IP3 and ryanodine receptors (RyR) completely eliminated the rise in [ATP]m. GLP-1 appeared to prompt Ca2+-induced Ca2+ release through IP3 receptors via a protein kinase A (PKA)-mediated phosphorylation event, since ryanodine-insensitive [ATP]m increases were abrogated with the PKA inhibitor, H89. In contrast, the effects of GLP-1 on RyR-mediated [ATP]m increases were apparently mediated by the cAMP-regulated guanine nucleotide exchange factor cAMP-GEFII, since xestospongin C-insensitive [ATP]m increases were blocked by a dominant-negative form of cAMP-GEFII (G114E,G422D). Taken together, these results demonstrate that GLP-1 potentiates glucose-stimulated insulin release in part via the mobilization of intracellular Ca2+, and the stimulation of mitochondrial ATP synthesis.
Involvement of phospholipase D in insulin-like growth factor-I-induced activation of extracellular signal-regulated kinase, but not phosphoinositide 3-kinase or Akt, in Chinese hamster ovary cells
Authors: BANNO Yoshiko , TAKUWA Yoh , YAMADA Momoko , TAKUWA Noriko , OHGUCHI Kenji , HARA Akira , NOZAWA Yoshinori
Published: February 2003

Available evidence suggests the involvement of phospholipase D (PLD) in cell proliferation and survival. Phosphoinositide 3-kinase (PI 3-kinase)/Akt and extracellular signal-regulated kinases (ERKs) are signalling molecules that have essential roles in cell proliferation and survival. We previously demonstrated that sphingosine 1-phosphate (S1P)-induced PLD activation via the G-protein-coupled receptor endothelial differentiation gene (EDG) 3/S1P3 was involved in S1P-induced stimulation of PI 3-kinase and Akt. In the present study, we examined the involvement of two PLD isozymes, PLD1 and PLD2, in insulin-like growth factor (IGF)-I receptor tyrosine kinase-mediated stimulation of PI 3-kinase/Akt and ERKs. IGF-I and to a lesser degree S1P stimulated PI 3-kinase activity in Chinese hamster ovary cells overexpressing EDG3/S1P3. IGF-I-induced ERK phosphorylation was suppressed by butan-1-ol, but not butan-2-ol, whereas no effect of butanol was observed in IGF-I-induced Akt activation in S1P3-overexpressing Chinese hamster ovary cells. Overexpression of wild-type PLD1 and PLD2 substantially potentiated S1P-, but not IGF-I-, induced activation of PI 3-kinase and Akt, whereas overexpression of the catalytically inactive mutant of PLD1 or PLD2 did not affect the responses to either agonist. On the other hand, overexpression of wild-type PLD1 and PLD2 potentiated IGF-I- and, to much smaller extents, S1P-induced ERK stimulation. ERK activation by IGF-I as well as S1P was dependent on Ras, but Akt activation by IGF-I was not dependent on Ras. These results suggest that PLDs are involved in growth factor regulation of at least two signalling pathways, PI 3-kinase/Akt and ERKs, depending on the class of cell-surface receptors.
Sulphoacetaldehyde acetyltransferase yields acetyl phosphate: purification from Alcaligenes defragrans and gene clusters in taurine degradation
Authors: RUFF Jürgen , DENGER Karin , COOK Alasdair M.
Published: February 2003

The facultatively anaerobic bacterium Alcaligenes defragrans NKNTAU was found to oxidize taurine (2-aminoethanesulphonate) with nitrate as the terminal electron acceptor. Taurine was transaminated to 2-sulphoacetaldehyde. This was not converted into sulphite and acetate by a ‘sulphoacetaldehyde sulpho-lyase’ (EC 4.4.1.12), but into sulphite and acetyl phosphate, which was identified by three methods. The enzyme, which required the addition of phosphate, thiamin diphosphate and Mg2+ ions for activity, was renamed sulphoacetaldehyde acetyltransferase (Xsc; EC 2.3.1.-). Inducible Xsc was expressed at high levels, and a three-step 11-fold purification yielded an essentially homogeneous soluble protein, which was a homotetramer in its native form; the molecular mass of the subunit was found to be between about 63kDa (SDS/PAGE) and 65.3kDa (matrix-assisted laser-desorption ionization—time-of-flight MS). The N-terminal and two internal amino acid sequences were determined, and PCR primers were generated. The xsc gene was amplified and sequenced; the derived molecular mass of the processed protein was 65.0kDa. The downstream gene presumably encoded the inducible phosphate acetyltransferase (Pta) found in crude extracts. The desulphonative enzymes ('EC 4.4.1.12') from Achromobacter xylosoxidans NCIMB 10751 and Desulfonispora thiosulfatigenes GKNTAU were shown to be Xscs. We detected at least three subclasses of xsc in Proteobacteria and in Gram-positive bacteria, and they comprised a distinct group within the acetohydroxyacid synthase supergene family. Genome sequencing data revealed xsc genes in Burkholderia fungorum (80% sequence identity) and Sinorhizobium meliloti (61%) with closely linked pta genes. Different patterns of regulation for the transport and dissimilation of taurine were hypothesized for S. meliloti and B. fungorum.
Cloning and characterization of multiple human polyamine oxidase splice variants that code for isoenzymes with different biochemical characteristics
Authors: MURRAY-STEWART Tracy , WANG Yanlin , DEVEREUX Wendy , CASERO Robert A.
Published: February 2003

The recently cloned and characterized human polyamine oxidase (PAOh1) potentially represents a new class of catabolic enzymes in the mammalian polyamine metabolic pathway capable of the efficient oxidation of polyamines. Here the discovery of three additional human PAO splice variants is reported, and the data support the fact that the human PAO gene codes for at least four isoenzymes, each of which exhibit distinctive biochemical characteristics, suggesting the existence of additional levels of complexity in polyamine catabolism.
Tension at the Nexus of the Global and Local: Culture, Property, and Marine Aquaculture in Hawai'i
Authors: Suryanata Krisnawati , Umemoto Karen N
Published: February 2003

Technological development in open-ocean mariculture has opened up the possibility of a new growth industry for Hawai'i, yet its introduction has not been without controversy. Marine aquaculture requires changes in property institutions that govern the ocean space, a key resource for marine aquaculture. This paper examines initial opposition to ocean leasing as a way of under-standing the contradictory technical and societal demands of a technological project. We incorporate insights from agrofood studies that emphasize the importance of building networks if the industry is to succeed within the globalized food systems. We argue that comprehensive and synthetic analysis at the ‘front end’ of a technological project is critical to identify strategic issues that need to be addressed; and that insights from planning literature bring in potential tools for organizing actions to negotiate the tension and to (re)contextualize a technological project such as this.
Love Thy Neighbourhood—Rethinking the Politics of Scale and Walsall's Struggle for Neighbourhood Democracy
Authors: Whitehead Mark
Published: February 2003

Despite its apparent irrelevance as a scale or space of sociocultural organisation, the neighbourhood is back on the political agenda. At an international level, the neighbourhood—or, more specifically, the ‘global neighbourhood'—is being promoted as a moral space through which to manage the complex economic, political, and ecological problems of the planet. Mirroring this process at a national level, in the United Kingdom the neighbourhood has been rediscovered and now provides the parameters through which a range of antipoverty, welfare, and local democracy programmes are being delivered. In light of its contemporary political popularity, this paper presents a critical reanalysis of the concept of the neighbourhood. In particular, the analysis explores the ideological and political uses of the ideal of neighbourhood, and how these processes relate to a particular ‘politics of scale'. In order to unpack the various politics of scales associated with the neighbourhood, the analysis combines theories of scale with Lefebvre's work on the production of space. Drawing on these theoretical insights and the case of neighbourhood politics in the town of Walsall in the United Kingdom, I explore the political narratives and practices through which the neighbourhood scale is produced and contested, and question the ability of neighbourhoods, as they are currently being constructed in the United Kingdom, to offer locally empowering scales of political and social organisation.
Agro-Food System Restructuring and the Geographic Concentration of US Swine Production
Authors: Welsh Rick , Hubbell Bryan , Carpentier Chantal Line
Published: February 2003

The US swine industry has dramatically reorganized over the last two decades. Economic concentration in the slaughter sector has increased and hog production has consolidated economically and geographically. Increases in the geographic concentration of hog production have led to water pollution through spills and leakage from high numbers of very large manure storage lagoons centered within limited areas, such as a few counties. The global restructuring of agro-food systems has promoted the development of intensive and concentrated livestock production. However, national, state and local institutions, and dynamics have also influenced the structure of geographic concentration of hog production. Using state-level and national-level time series data from 1975–1996, we find that national-level increases in concentration in the hog-processing sector are positively associated with geographic concentration of production within states. However, we also find that state, and even local, government policy can mitigate, or worsen, the geographic concentration of hog production.
Homeless Mobility, Institutional Settings, and the New Poverty Management
Authors: DeVerteuil Geoffrey
Published: February 2003

Poverty management involves organized responses by elites and/or the state to contain potentially disruptive populations. As a result of global, national, and institutional compressions, the new poverty management tends to circulate these populations, especially the mentally disabled, across an array of unrelated and frequently institutional settings. This restructuring of interactions between mobility and institutional settings, in the form of institutionalized cycling, has yet to be investigated for other potentially vulnerable groups, such as single homeless women. Using a convenience sample of twenty-five women at a shelter in Central Los Angeles, I seek to understand their residential patterns, identify evidence of institutionalized cycling through a fivefold typology, and to elucidate the personal and structural factors behind why some women were prone to institutionalized cycling whereas others were not. Results point to highly uneven evidence of institutionalized cycling across the sample, with the most obvious impacts in the institutional cycler and institutionally accommodated categories.
The Life Course and Residential Mobility in British Housing Markets
Authors: Clark William A V , Huang Youqin
Published: February 2003

There is a substantial research literature on residential mobility in general, and the role of housing space in triggering moves in particular. The authors extend that research to mobility in British housing markets, using data from the British Household Panel Survey. They confirm the applicability of the general residential mobility model and also confirm the value both of pooled cross-sectional and of true longitudinal models of residential change. Age, tenure, and room stress (housing-space requirements) are found to be significant predictors of moving. In addition, the life course ‘triggers' of marital-status change and, in some situations, birth of a child play important roles in moving within housing markets in the United Kingdom. The same model, with somewhat lower levels of fit, is also significant for the London region. Variables that measure the desire to move and neighborhood satisfaction also play a role in predicting local moves: those who like their neighborhood are generally less likely to move. The results offer support for the view that residential mobility is a demographically driven process which also reflects the connection with neighborhood contexts.
Nonoptimal Levels of Suburbanization
Authors: Graves Philip E
Published: February 2003

Suburbanization has many causes, among which is the attempt to relocate to acquire a more desirable vector of local public goods. The traditional economists' procedure for valuing public goods involves vertical aggregation of marginal willingness to pay, at a given income level. This approach is flawed by failing to recognize that individuals will not work for goods that cannot be acquired individually with higher incomes. There will be a parallel input market failure any time there is a public good output market failure, thus the ‘given income’ of the traditional valuation method is too low. Hence, traditional valuation methods result in underprovision of local public goods (for example, parks, safety, education, and environmental quality) at the urban centers. As a consequence, there will be nonoptimally large levels of suburban sprawl with substantial resulting welfare loss.
A brief introduction to training prisoners within the British justice system in practical catering skills
Authors: Goodger Anthony
Published: February 2003

This paper provides a synopsis of the training of prisoners in HM prisons in Great Britain in catering skills. Experience of participants in various catering courses is detailed.
The effect of four Nigerian wheat flours on the loaf volume and sensory quality of bread
Authors: Keswet L.M. , Ayo J.A. , Bello C.B.
Published: February 2003

Four Nigerian wheat flours were purchased in Bauchi and Jos central markets. A preliminary survey of Nigerian bread, using a questionnaire, was carried out within the Bauchi metropolis. The four flours were used to produce bread, the volume index and sensory quality of the products were assessed and the data subjected to analysis of variance, p ≤q 0.05. A very high percentage of those examined (90.2 percent) consume bread, though only 52.2 percent do so regularly. Softness, sweet taste, and the slight brown colour of these bread qualities were given greater preference. The proximate analysis of these wheat flours range from 12.59‐12.81 (moisture), 12.36‐14.20 (crude protein), 1.40‐2.40 (crude fibre), 1.57‐1.72 (lipids), 0.79‐0.81 (ash), 0.34‐0.44 (calcium), 0.07‐0.08 (phosphorous). The volume index of the breads produced are 3.8, 3.6, 3.45 and 3. The sensory quality (colour, texture, flavour) were significantly affected, p ≤q 0.05, by the variety of the wheat flour.
Towards a framework for operations management in e‐commerce
Authors: da Silveira Giovani J.C.
Published: February 2003

This paper identifies areas of distinctive competence in the operations function of e‐commerce companies. Exploratory case studies were conducted in five e‐commerce companies in Argentina. The distinctive competencies that emerged were divided into three sets referring to upstream, downstream, and structural areas and integrated into a framework of the general e‐commerce process. The findings suggest that operations‐based competitiveness in e‐commerce requires the development of a series of distinctive competencies, that those competencies are often related and mutually supportive, and that there is usually a linkage between distinctive competencies in e‐commerce operations and the business strategy.
Some moderating effects on the service quality‐customer retention link
Authors: Ranaweera Chatura , Neely Andy
Published: February 2003

This paper presents a holistic model of customer retention incorporating service quality perceptions, price perceptions, customer indifference and inertia. Data from a large‐scale postal survey of telephone users in England showed that perceptions of service quality have a direct linear relationship with customer retention even in mass services with low customer contact. Price perceptions and customer indifference too were found to have a direct linear effect on retention. Furthermore, it was also seen how both price perceptions and customer indifference moderated the relationship between service quality perceptions and customer retention. A linear relationship between inertia and customer retention was not found. Furthermore, there was evidence to indicate that inertia was a relatively unstable condition and that reliance by service providers on inertia to retain customers could indeed be a risky strategy.
Management development: in search of a new role?
Authors: Kirkbride Paul S.
Published: February 2003

This paper argues, based on academic research as well as personal experience, that management development (MD) functions are not always utilising their resources, either in terms of people or time, effectively. They are perceived to spend large amounts of their time on “administrative” or “welfare” aspects of the role whilst neglecting some of the more strategic issues or roles. Using a model of HR roles, we explore the potential roles for the MD function, analysing exactly what each role would imply for MD activities. We conclude by suggesting that MD is in many cases in danger of becoming left behind as the rest of the HR function moves onto more strategic concerns. Thus the challenge is to forge a more strategic role, either as a strategic business partner or as a change agent.
Using value equations to analyse exchanges
Authors: Blois Keith
Published: February 2003

The concept of exchange is considered and the insights that this provides are combined with Day’s concept of customer value equations to propose that there is also a need to evaluate the supplier’s value equation. Examples of how both customer and supplier value equations might be used by a supplier to further its understanding of the relationships which it has with customers are discussed.
The internationalization of US Internet portals: does it fit the process model of internationalization?
Authors: Kim Daekwan
Published: February 2003

Although the theory of the gradual internationalization of firms has been widely studied and supported by researchers, very little is known about the internationalization of electronic commerce firms. This study conducted a case study on Yahoo! Inc., AOL, Lycos, and AltaVista. Spearman correlation and Kendall’s tau analyses along with two proxy psychic distance indices were deployed to investigate whether the gradual internationalization theory can be applied to electronic commerce firms. The results reveal that the gradual internationalization of Internet firms is better supported by the sociocultural distance index than the cultural distance index. Some implications of findings are also discussed along with other characteristics of the internationalization of the Internet portal firms.
Improving workplace material handling through consolidation of cribs and a dispatching system
Authors: Das Biman , Garcia‐Diaz Alberto
Published: February 2003

The lost time arising from travelling and waiting of the production operators and manufacturing inspectors at the tool and gauge crib counters can be considerable in a large manufacturing plant. This travelling and waiting time can be eliminated or minimized by consolidating the tool and gauge cribs near the master crib, extending the totebox system and providing a dispatching system. In the proposed system the tools and gauges will be delivered at the workstation by the dispatchers. The new system would improve the utilization of the tool and gauge crib attendant’s time and reduce the tool and gauge inventory. The case problem revealed that a net annual labor cost saving of about $320,600 and a saving of $242,100 from the reduction of tool and gauge inventory could be achieved. The additional floor space requirement would be about 1,700sq. ft and the implementation cost would be about $144,500.
Manufacturing reengineering in a tubular radiator production plant
Authors: Caputo Antonio C. , Pelagagge Pacifico M.
Published: February 2003

Describes the reengineering of a production line for household heating tubular radiators, assuming as a reference scenario the facility of one of the leading Italian manufacturers. After a preliminary characterization of products and manufacturing process, a thorough analysis of the production system has been carried out in order to highlight current problems and improvement strategies in the light of lean manufacturing concepts. Subsequently, suggests some corrective actions and also assesses their expected effectiveness in economic terms. In particular, improvement possibilities have been found in the areas of internal logistics through streamlining of materials flow and layout modifications, as well as process quality increase. Reengineering activities are especially aimed towards layout optimization mainly by resorting to a U‐shaped cell‐based architecture. Further, the reduction of rework percentage during the assembly phase has been pursued by properly modifying the operations sequence and through integration of a new automated testing station in the production line.
Strategies for agility: an evolutionary and configurational approach
Authors: McCarthy Ian , Tsinopoulos Christos
Published: February 2003

Configurational theory can significantly enhance understanding of organisational strategy and diversity. Despite this, there have been limited efforts to examine the value and utility of configurational research as a method for realising manufacturing strategies. This paper introduces a strategic management framework based on configurational theory and an evolutionary classification method (cladistics). Focusing on agile manufacturing concepts, the framework provides a system for collecting and organising information on manufacturing routines and capabilities. This facilitates the processes of strategic analysis, strategic choice and strategic information.
Quality management practice in semiconductor manufacturing industries – empirical studies in Taiwan
Authors: Yang Taho , Chen Mu‐Chen , Su Chao‐Ton
Published: February 2003

Semiconductor manufacturing is in the spotlight of the global manufacturing industries. Quality management is strategically and tactically important for gaining a competitive advantage. Since Taiwan’s semiconductor industry is one of the major suppliers of global semiconductor products, its quality management practice has a global impact. This research was conducted based on a proven measurement instrument for quality management practices including eight critical factors and 63 measuring items. Data were analyzed with respect to their reliability, mean rank, consistency, and correlation. Analysis results revealed insights into managers’ perception of quality management practices in the semiconductor industries.
Dynamic scheduling of flexible manufacturing systems using neural networks and inductive learning
Authors: Priore Paolo , de la Fuente David , Pino Rau´l , Puente Javier
Published: February 2003

Dispatching rules are usually applied dynamically to schedule jobs in flexible manufacturing systems. Despite their frequent use, one of the drawbacks that they display is that the state the manufacturing system is in dictates the level of performance of the rule. As no rule is better than all the other rules for all system states, it would be highly desirable to know which rule is the most appropriate for each given condition, and to this end this paper proposes a scheduling approach that employs inductive learning and backpropagation neural networks. Using these latter techniques, and by analysing the earlier performance of the system, “scheduling knowledge” is obtained whereby the right dispatching rule at each particular moment can be determined. A module that generates new control attributes is also designed in order to improve the “scheduling knowledge” that is obtained. Simulation results show that the proposed approach leads to significant performance improvements over existing dispatching rules.
LOOP VARIABLES IN STRING THEORY
Authors: SATHIAPALAN B.
Published: February 2003

The loop variable approach is a proposal for a gauge-invariant generalization of the sigma-model renormalization group method of obtaining equations of motion in string theory. The basic guiding principle is space–time gauge invariance rather than world sheet properties. In essence it is a version of Wilson's exact renormalization group equation for the world sheet theory. It involves all the massive modes and is defined with a finite world sheet cutoff, which allows one to go off the mass-shell. On shell the tree amplitudes of string theory are reproduced. The equations are gauge-invariant off shell also. This paper is a self-contained discussion of the loop variable approach as well as its connection with the Wilsonian RG.
PHOTON EXCHANGE IN NUCLEUS–NUCLEUS COLLISIONS
Authors: BERTULANI CARLOS A.
Published: February 2003

The strong electromagnetic fields in peripheral heavy ion collisions give rise to photon–photon and photon–nucleus interactions. I present a general survey of the photon–photon and photon-hadron physics accessible in these collisions. Among these processes I discuss the nuclear fragmentation through the excitation of giant resonances, the Coulomb dissociation method for application in nuclear astrophysics, and the production of particles.
MATTER FIELDS FROM A DECAYING BACKGROUND Λ VACUUM
Authors: MBONYE MANASSE R.
Published: February 2003

We suggest an alternative framework for interpreting the current state of the visible universe. Our approach is based on a dynamical "cosmological constant" and the starting point is that a decaying vacuum produces matter. By assuming inflation and big bang nucleosynthesis we can solve for the present fractional densities of matter Ωm,0 and vacuum ΩΛ,0 in terms of only one parameter which we call the vacuum domination crossing redshift, zc. We put constraints on zc to obtain a universe that is presently vacuum dominated and with characteristic densities consistent with observations. The model points to the possible existence of newly formed dark matter in the inter-cluster voids. We argue that some of this matter could be accreting onto clusters through the latter's long range gravitational potentials. If so, then cluster dark matter halos may not manifest clear cut-offs in their radial density profiles. Furthermore, if a substantial amount of this newly produced matter has already drained onto the clusters, then the CMB power spectrum may favor lower dark matter density values than is currently observed bound in the clusters. A final feature of our approach relates to the combined effect of the matter production by a decaying vacuum and the different rates at which matter and the vacuum will dilute with the scale factor. Such combinations may create conditions for a universe in which the vacuum and matter densities dilute and evolve towards comparable amplitudes. In this sense the model offers a natural and conceptually simple explanation to the coincidence problem. It also suggests that the universe may be stable to vacuum-induced runaway accelerations.
HADRON PRODUCTION IN NEUTRINO–NUCLEON INTERACTIONS AT HIGH ENERGIES
Authors: HUSSEIN M. T. , HASSAN N. M. , ELHARBI W.
Published: February 2003

The multi-particle productions in neutrino–nucleon collisions at high energy are investigated through the analysis of the data of the experiment CERN-WA-025 at neutrino energy less than 260 GeV and the experiments FNAL-616 and FNAL-701 at energy range 120–250 GeV. The general features of these experiments are used as base to build a hypothetical model that views the reaction through a Feynman diagram of two vertices. The first of which concerns the weak interaction between the neutrino and the quark constituents of the nucleon. At the second vertex, a strong color field is assumed to play the role of particle production, which depend on the momentum transferred from the first vertex. The wave functions of the nucleon constituent quarks are determined using the variation method and relevant boundary conditions are applied to calculate the deep inelastic cross sections of the virtual diagram.
ELECTRONIC BOUND STATES IN PARITY-PRESERVING QED3 APPLIED TO HIGH-Tc CUPRATE SUPERCONDUCTORS
Authors: CHRISTIANSEN H. R. , DEL CIMA O. M. , FERREIRA M. M. , HELAYËL-NETO J. A.
Published: February 2003

We consider a parity-preserving QED 3 model with spontaneous breaking of the gauge symmetry as a framework for the evaluation of the electron–electron interaction potential underlying high-T c superconductivity. The fact that the resulting potential, -CsK0(Mr), is non-confining and "weak" (in the sense of Kato) strongly suggests the mechanism of pair-condensation. This potential, compatible with an s-wave order parameter, is then applied to the Schrödinger equation for the sake of numerical calculations, thereby enforcing the existence of bound states. The results worked out by means of our theoretical framework are checked by considering a number of phenomenological data extracted from different copper oxide superconductors. The agreement may motivate a deeper analysis of our model viewing an application to quasiplanar cuprate superconductors. The data analyzed here suggest an energy scale of 1–10 meV for the breaking of the U(1)-symmetry.
EQUIVALENCE BETWEEN DIFFERENT CLASSICAL TREATMENTS OF THE O(N) NONLINEAR SIGMA MODEL AND THEIR FUNCTIONAL SCHRÖDINGER EQUATIONS
Authors: DERIGLAZOV A. A. , OLIVEIRA W. , OLIVEIRA-NETO G.
Published: February 2003

In this work we derive the Hamiltonian formalism of the O(N) nonlinear sigma model in its original version as a second-class constrained field theory and then as a first-class constrained field theory. We treat the model as a second-class constrained field theory by two different methods: the unconstrained and the Dirac second-class formalisms. We show that the Hamiltonians for all these versions of the model are equivalent. Then, for a particular factor-ordering choice, we write the functional Schrödinger equation for each derived Hamiltonian. We show that they are all identical which justifies our factor-ordering choice and opens the way for a future quantization of the model via the functional Schrödinger representation.
RIGHT-HANDED MAJORANA NEUTRINO MASS MATRICES FOR GENERATING BIMAXIMAL MIXINGS IN DEGENERATE AND INVERTED MODELS OF NEUTRINOS
Authors: PATGIRI MAHADEV , NIMAI SINGH N.
Published: February 2003

An attempt is made to generate the bimaximal mixings of the three species of neutrinos from the textures of the right-handed Majorana neutrino mass matrices. We extend our earlier work in this paper for the generation of the nearly degenerate as well as the inverted hierarchical models of the left-handed Majorana neutrino mass matrices using the non-diagonal textures of the right-handed Majorana neutrino mass matrices and the diagonal form of Dirac neutrino mass matrices, within the framework of the see-saw mechanism in a model independent way. Such Majorana neutrino mass models are important in explaining the recently reported result on the neutrinoless double beta decay (0νββ) experiment, together with the earlier established data on LMA MSW solar and atmospheric neutrino oscillations.
ORDER FROM DISORDER: THE ROLE OF NOISE IN CREATIVE PROCESSES. A SPECIAL ISSUE ON GAME THEORY AND EVOLUTIONARY PROCESSES – OVERVIEW
Authors: ABBOTT DEREK , DAVIES PAUL C. W. , SHALIZI COSMA R.
Published: February 2003

The importance of applying game theory to the evolution of information in the presence of noise has recently become widely recognized. This Special Issue addresses the theme of spontaneously emergent order in both classical and quantum systems subject to external noise, and includes papers directly related to game theory or the development of supporting techniques. In the following editorial overview we examine the broader context of the subject, including the tension between the destructive and creative aspects of noise, and foreshadow the significance of some of the subsequent papers in the volume.
Fabrication of Ordered Macroporous Structures Based on Hetero-Coagulation Process Using Nanoparticle as Building Blocks
Authors: Tang Fengqiu , Fudouzi Hiroshi , Uchikoshi Tetsuo , Awane Toru , Sakka Yoshio
Published: February 2003

A simple method based on hetero-coagulation process for the preparation of well-defined ordered macroporous inorganic materials from nanoparticles and spherical polymer templates is reported.