bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of three successive antiviral treatments on viral heterogeneity in nonresponder chronic hepatitis C patients
Authors: Thelu Marie‐Ange , Brengel‐Pesce Karen , Leroy Vincent , Attuil Valérie , Drouet Emmanuel , Seigneurin Jean‐Marie , Zarski Jean‐Pierre
Published: August 2002

The purpose of the present study was to assess the viral diversity of hepatitis C virus (HCV) in six nonresponder patients during three unsuccessful treatments. These patients were treated successively with IFN‐α2a (IFN‐α) at a posology of 3.106 units (MIU) three times a week, 10 MIU three times a week, and a combination of IFN‐α (3 MIU) plus ribavirin (1,000 mg/day). However, only two chronically infected patients could be included in the study due to the persistence of HCV RNA during the three successive treatments. The viral diversity was analysed by cloning and sequencing the HVR‐1 region. The treatment of the two nonresponder patients was associated with the persistence of a wide diversity in the viral population and with the emergence of new or minor variants. Under the influence of standard doses of IFN‐α, a rearrangement of the quasispecies present was observed at this time point. No significant change in viral load or in the complexity of the quasispecies was observed. A second treatment with a high dose of IFN‐α induced a significant decrease in the associated viral load and, in one case, resulted in a radical change of the viral diversity. Administration of a combination of IFN‐α and ribavirin did not affect the evolution of the variants but was followed by the emergence of various multiple variants. These results reinforce the hypothesis of the presence of preexisting quasispecies best adapted to the host environment, and therefore resistant to any current therapy. J. Med. Virol. 65:698–705, 2001. © 2001 Wiley‐Liss, Inc.
Antibody responses against B‐cell epitopes of the hypervariable region 1 of hepatitis C virus in self‐limiting and chronic human hepatitis C followed‐up using consensus peptides
Authors: Isaguliants Maria G. , Widell Anders , Zhang Shumin M. , Sidorchuk Anna , Levi Michael , Smirnov Valerii D. , Santantonio Teresa , Diepolder Helmut M. , Pape Gerd R. , Nordenfelt Erik
Published: August 2002

A rare collection of serum samples from patients with hepatitis C virus (HCV) infection followed up from the onset of clinical symptoms was acquired. RNA corresponding to the hypervariable region 1 (HVR1) of E2 protein of HCV isolated from nine patients was reverse‐transcribed, amplified, sequenced, and HVR1 amino acid sequences were deduced. These sequences and a selection of HVR1 amino acid sequences of matching HCV genotypes from protein and translated DNA sequence databanks were used to create the HVR1 amino acid consensus. The degenerated peptides mimicking N‐ and C‐termini of the consensus were synthesized. Most (76%) of 17 patients followed up for the period from 1 week to a minimum of 7 months from the onset of acute symptoms developed antibodies reacting with peptides representing N‐ and/or C‐ termini of HVR1. Antibody recognition of the consensus HVR1 peptides indicates that the variability of HVR1 sequence on the protein level is limited with certain conserved structure(s) being untouched. A tendency was observed for a slower development of anti‐HVR1 antibody response in patients developing chronic HCV, as compared to those with self‐limiting HCV infection. J. Med. Virol. 66:204–217, 2002. © 2002 Wiley‐Liss, Inc.
HHV‐8 subtypes in South Africa: Identification of a case suggesting a novel B variant
Authors: Treurnicht Florette K. , Engelbrecht Susan , Taylor Maureen B. , Schneider Johan W. , van Rensburg Estrelita Janse
Published: August 2002

Human herpesvirus 8 (HHV‐8) has been identified as the causative agent for all forms of Kaposi's sarcoma and is also associated with the development of body cavity‐based B‐cell lymphomas and multicentric Castleman's disease. HHV‐8 genomes are now classified into five major subtypes (A–E) that reflect sequence heterogeneity in the highly variable open reading frame (ORF) K1. To identify HHV‐8 subtypes associated with different forms of Kaposi's sarcoma, we compared the ORF 26 and ORF‐K1 gene sequences from South African patients with the prototype strains of the major subtypes, as well as published sequences from other African strains. DNA prepared from Kaposi's sarcoma biopsies and/or peripheral blood lymphocytes were available from 14 patients with postrenal transplant (iatrogenic) Kaposi's sarcoma, six patients with the African endemic form, and one patient with AIDS‐related body cavity‐based B‐cell lymphoma. We identified a B2 subtype in six patients, four of whom also had a novel B5 type ORF 26 polymorphism. Two patients had B2 type patterns for both the ORF 26 and ORF‐K1 genes. The ORF‐K1 subtype A5 was identified in samples from three patients with a B3/C2 type polymorphism in the ORF 26 gene. A novel ORF‐K1 B variant strain was identified in a patient with African endemic Kaposi's sarcoma, who also had a B3/C2 class ORF 26 pattern. In 58.3% of iatrogenic Kaposi's sarcoma patients, a B5‐type ORF 26 gene sequence pattern was identified. No association was found among particular subtypes, geographical origin of patients, or clinical presentation. J. Med. Virol. 66:235–240, 2002. © 2002 Wiley‐Liss, Inc.
Routine use of real‐time quantitative PCR for laboratory diagnosis of Epstein‐Barr virus infections
Authors: Brengel‐Pesce Karen , Morand Patrice , Schmuck Anne , Bourgeat Marie‐Josette , Buisson Marlyse , Barguès Gérard , Bouzid Makhlouf , Seigneurin Jean‐Marie
Published: August 2002

Real‐time quantitative polymerase chain reaction (PCR) on the LightCycler instrument (LC‐PCR) was developed to measure the Epstein‐Barr virus (EBV) load in clinical samples. LC‐PCR detected two copies of the EBV genome per 500 ng of DNA. Its specificity was confirmed by assays in EBV‐negative cell lines, other human herpesviruses and EBV‐seronegative individuals. Excellent inter‐assay reproducibility of LC‐PCR was obtained in 43 samples (r = 0.983). LC‐PCR results were compared with a routinely used ELISA‐PCR of 150 samples and a good correlation was found (r = 0.956). A total of 88 individuals were studied, including healthy EBV‐seropositive adults (n = 32), patients with EBV‐associated disease (n = 34), and HIV‐infected patients (n = 22); 37.5% of PBMC samples from healthy individuals contained EBV DNA, while no serum sample was positive. The viral load was significantly higher in PBMCS and saliva specimens in patients recently infected with HIV (19 and 39,400 copies/μg DNA, respectively), as well as in AIDS patients (122 and 331,130 copies/μg DNA) than in the control population (0 and 35 copies/μg DNA). This study confirmed that EBV load measurement with LC‐PCR is helpful in the management of EBV‐related post‐transplantation lymphoproliferative disorders and probably of EBV‐associated primary central nervous system B‐cell lymphoma. J. Med. Virol. 66:360‐369, 2002. © 2002 Wiley‐Liss, Inc.
Cellular tropisms and co‐receptor usage of HIV‐1 isolates from vertically infected children with neurological abnormalities and rapid disease progression
Authors: McCarthy Micheline , He Jun , Auger Denise , Geffin Rebeca , Woodson Cristina , Hutto Cecelia , Wood Charles , Scott Gwendolyn
Published: August 2002

The longitudinal evolution of HIV‐1 phenotypes was studied in a cohort of six vertically infected children with early onset and rapid progression of clinical disease. Among 30 viral isolates obtained from peripheral blood, tropisms for both human blood‐derived cells (macrophages, T‐lymphocytes), and for human neural (brain‐derived) cells (microglia, astrocytes) were determined, as was chemokine co‐receptor usage. All children harbored from birth macrophage‐tropic isolates using the CCR5 co‐receptor. Two children later developed T‐cell tropic isolates with CXCR4 and CCR3 usage. While all six patients developed neurological abnormalities, only three produced neural cell tropic isolates, which used CCR5. However, early and persistent finding of both astrocyte‐ and microglia‐tropic isolates in one patient did associate with the most rapid progression to brain atrophy among the six patients. Viral phenotypic properties determined in cell culture did not specifically predict clinical features or course, and the development of AIDS did not coincide with, or depend on, the appearance T‐tropic, syncytia‐inducing viruses. J. Med. Virol. 67:1–8, 2002. © 2002 Wiley‐Liss, Inc.
Numerical modelling of anisotropy and eddy current effects in ferromagnetic laminations using a co‐energy formulation
Authors: Dupré L. R. , Van Keer R. , Melkebeek J. A. A.
Published: August 2002

The paper deals with a numerical model for the evaluation of electromagnetic fields in one steel lamination under the influence of a rotating magnetic flux, taking into account anisotropy effects. For this purpose a detailed material model, described by a differential permeability tensor, is included in the macroscopic electromagnetic field calculations in one lamination. Here, by geometrical and physical considerations, the governing Maxwell equations are reduced to a system of parabolic PDEs for the components of the magnetic field vector, under appropriate boundary and initial conditions. We present a suitable numerical approximation based upon a finite element–finite difference method, which properly takes into account the material characteristics. The study leads to a more realistic numerical modelling of the electromagnetic phenomena inside electric and magnetic conducting laminations due to anisotropy effects. Numerical results are compared with those from simplified analytical formulae. Copyright © 2001 John Wiley & Sons, Ltd.
Effect of the iron chelator desferrioxamine on manganese‐induced toxicity of rat pheochromocytoma (PC12) cells
Authors: Roth Jerome A. , Feng Li , Dolan Kevin G. , Lis Agnieszka , Garrick Michael D.
Published: August 2002

Alterations in iron levels are likely to influence the biological actions of Mn in PC12 cells, because both metals are transported via the divalent metal transporter 1 (DMT1; also Nramp2 or DCT1). Studies were performed to determine the effect of the iron chelator desferrioxamine (DfO) on Mn‐induced PC12 cell death and neuronal differentiation. Cell death almost doubled when PC12 cells were exposed for 24 hr to both DfO (10 μM) and Mn (0.3 mM) as opposed to Mn alone. DfO also stimulated Mn‐induced neuronal differentiation by enhancing the phosphorylation of both ERK1 and 2 and also attenuated the increase in caspase 3‐like activity induced by 0.3 mM Mn by approximately 50%, indicating that caspase activation, as reported previously, does not contribute to Mn‐induced PC12 cell death. DfO also affected Mn‐induced suppression of mitochondrial function as indicated by an additional 16% loss of ATP formation in PC12 cells cotreated with 0.3 mM Mn. Because sequestration of iron by DfO would be expected to lead to increased transport of Mn, studies were performed to determine whether iron inhibited Mn transport in PC12 cells. Iron inhibited 54Mn transport with an IC50 of approximately 20 μM. In addition, coincubation of DfO with Mn in PC12 cells resulted in increased expression of both the iron response element‐positive and the iron response element‐negative forms of DMT1. Taken together, these results demonstrate that iron status is likely to have a direct effect on the uptake and biological actions of Mn and probably other divalent metals that are transported by DMT1. © 2002 Wiley‐Liss, Inc.
Expression of mouse igf2 mRNA‐binding protein 3 and its implications for the developing central nervous system
Authors: Mori Hiroshi , Sakakibara Shin‐ichi , Imai Takao , Nakamura Yuki , Iijima Takatoshi , Suzuki Akira , Yuasa Yoshihiro , Takeda Masatoshi , Okano Hideyuki
Published: August 2002

Functional analyses of neural RNA‐binding proteins have focused mainly on their roles as modulators of posttranscriptional gene regulation, e.g., alternative splicing, dendritic mRNA localization, and local translation. Here we identified a mouse homologue of human IMP3, which is known to bind to and repress the translation of igf2 leader 3 mRNA. The mouse igf2 mRNA‐binding protein 3 (mIMP3) is a member of the zipcode binding protein‐1 (ZBP‐1) family previously reported in chick fibroblast cells. mIMP3 was expressed in undifferentiated neuroepithelial cells and some postmitotic neurons at early embryonic stages (E10.5–E12.5), and its expression level decreased after the midembryonic stage (E12.5) until birth. The expression profile of mIMP3 is very similar to that of mouse igf2 leader 3 mRNA. In vitro UV cross‐linking experiments showed that mIMP3 preferentially bound to igf2 leader 3 mRNA rather than igf2 leader 4 mRNA and did not bind the zipcode region of β‐actin or c‐myc mRNA. Furthermore, persistent expression of mIMP3 protein in an undifferentiated P19 cell line revealed that mIMP3 inhibited neuronal differentiation morphologically and immunohistochemically. Taken together, these observations raise the possibility that mIMP3 represses neuronal differentiation through the regulation of igf2 mRNA expression. J. Neurosci. Res. 64:132–143, 2001. © 2001 Wiley‐Liss, Inc.
Brain‐derived neurotrophic factor triggers a rapid glutamate release through increase of intracellular Ca2+ and Na+ in cultured cerebellar neurons
Authors: Numakawa T. , Matsumoto T. , Adachi N. , Yokomaku D. , Kojima M. , Takei N. , Hatanaka H.
Published: August 2002

We reported previously that BDNF induced glutamate release was dependent on intracellular Ca2+ but not extracellular Ca2+ in cerebellar neurons (Numakawa et al., 1999). It was revealed that the release was through a non‐exocytotic pathway (Takei et al., 1998; Numakawa et al., 1999). In the present study, we monitored the dynamics of intracellular Ca2+ and Na+ in cerebellar neurons, and investigated the possibility of reverse transport of glutamate mediated by BDNF. As reported, BDNF increased the intracellular Ca2+ level. We found that the Ca2+ increase induced by BDNF was completely blocked by xestospongin C, an IP3 receptor antagonist, and U‐73122, a PLC‐γ inhibitor. Xestospongin C and U‐73122 also blocked the BDNF‐dependent glutamate release, suggesting that the BDNF‐induced transient increase of Ca2+ through the activation of the PLC‐γ/ IP3 pathway was essential for the glutamate release. We found that BDNF induced a Na+ influx. This was blocked by treatment with TTX. U‐73122 and xestospongin C blocked the BDNF‐induced Na+ influx, suggesting that the Na+influx required the BDNF‐induced Ca2+ increase. Next, we examined the possibility that a co‐transporter of Na+ and glutamate was involved in the BDNF‐induced glutamate release. BDNF‐induced glutamate release was blocked by L‐trans‐pyrollidine‐2,4‐dicalboxylic acid (t‐PDC), a glutamate transporter inhibitor, whereas neither the 4‐aminopyridine (4AP)‐ nor high potassium (HK+)‐induced release was blocked by t‐PDC. In addition, DL‐threo‐β‐benzyloxyaspartate (DL‐TBOA) also blocked the BDNF‐mediated glutamate release, suggesting that reverse transport of glutamate may be involved. All the results therefore suggest that Na+‐dependent reverse transport contributes to BDNF‐mediated transmitter release through the PLC‐γ/IP3‐mediated Ca2+ signaling. J. Neurosci. Res. 66:96–108, 2001. © 2001 Wiley‐Liss, Inc.
Cannabinoid receptor agonist WIN 55,212‐2 inhibits rat cortical dialysate γ‐aminobutyric acid levels
Authors: Ferraro Luca , Tomasini Maria Cristina , Cassano Tommaso , Bebe Berta Wonjie , Siniscalchi Anna , O'Connor William Thomas , Magee Pamela , Tanganelli Sergio , Cuomo Vincenzo , Antonelli Tiziana
Published: August 2002

The effects of the cannabinoid receptor agonist WIN 55,212‐2 (0.1–5 mg/kg i.p.) on endogenous extracellular γ‐aminobutyric acid (GABA) levels in the cerebral cortex of the awake rat was investigated by using microdialysis. WIN 55,212‐2 (1 and 5 mg/kg i.p.) was associated with a concentration‐dependent decrease in dialysate GABA levels (–16% ± 4% and –26% ± 4% of basal values, respectively). The WIN 55,212‐2 (5 mg/kg i.p.) induced‐inhibition was counteracted by a dose (0.1 mg/kg i.p.) of the CB1 receptor antagonist SR141716A, which by itself was without effect on cortical GABA levels. These findings suggest that cannabinoids decrease cortical GABA levels in vivo, an action that might underlie some of the cognitive and behavioral effects of acute exposure to marijuana. J. Neurosci. Res. 66:298–302, 2001. © 2001 Wiley‐Liss, Inc.
Evaluation of 360 degree feedback ratings: relationships with each other and with performance and selection predictors
Authors: Beehr Terry A. , Ivanitskaya Lana , Hansen Curtiss P. , Erofeev Dmitry , Gudanowski David M.
Published: August 2002

Feedback from 360 degree ratings based on competency principles and used for developmental purposes was investigated for interrelationships among the ratings and for its relationships with performance and selection data. Relationships among: (1) feedback ratings from supervisors, peers, and self; (2) feedback ratings and selection test data; and (3) feedback ratings and performance appraisals on about 2000 employees of a Midwestern insurance company were examined. The 360 ratings by peers and managers were related to performance appraisals. All significant correlations of manager and peer ratings with selection tests were positive, but significant correlations of 360 degree self‐ratings with selection tests were negative. Copyright © 2001 John Wiley & Sons, Ltd.
Team reward attitude: construct development and initial validation
Authors: Shaw Jason D. , Duffy Michelle K. , Stark Eric M.
Published: August 2002

This paper reports the development of a team reward attitude construct and intial validation of a measure in a longitudinal study of team members (initial n = 566). Confirmatory factor analysis results provide support for a revised 9‐item scale in two different time periods separated by four months. The measure was positively related to other team‐related attitudes (preference for group work and perceived efficacy of teams) and locus of control, and negatively related to a proxy for ability. Implications of the research and future research directions are addressed. Copyright © 2001 John Wiley & Sons, Ltd.
A multiple motive perspective on strike propensities
Authors: Martin James E. , Sinclair Robert R.
Published: August 2002

Strike propensities refer to the extent to which union members are willing to engage in strikes. The present paper identifies four motivational explanations for individual propensity to strike: social exchange relationships between member and union, and member and company, economic circumstances, and social status. These four models complement each other, and together permit substantial integration of previous literature as well as suggesting new antecedents of strike propensities. We evaluated each model using survey data from 2548 unionized retail employees. While the economic model explained the most variance in strike propensity, each model accounted for a significant amount of unique variation in the members' strike propensities. Our organizational framework of the motivational explanations of strike propensity into four distinct but complementary motivational models and our addition of new predictor variables represent our study's major contributions. Implications for strike research and union member–union relations are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Winter temperature covariances in the middle and the lower troposphere over Europe and the North Atlantic Ocean
Authors: Lolis C.J. , Bartzokas A.
Published: August 2002

In this work, the variability and covariability of winter temperatures in the middle and the lower troposphere are studied over Europe and the North Atlantic Ocean. Temperature variations of the middle and the lower troposphere are examined in terms of (a) 500–700 hPa and 700–l000 hPa thickness and (b) air temperature on the isobaric surfaces of 500 hPa and 700 hPa. At first, factor analysis (FA) defined areas with characteristic temperature variability in each layer (and on each isobaric surface) and then, canonical correlation analysis (CCA) revealed areas in both layers (and on both isobaric surfaces) presenting common temperature variations. A temperature see‐saw between N Europe and W Asia was revealed for both layers and isobaric surfaces implying that temperature changes in these areas are vertically spread. Another well‐defined area, appearing in both analyses, is the area of the Labrador Sea and S Greenland. This region is also teleconnected to other regions, though not very clearly in every height. These temperature patterns are mainly attributed to the Eurasian (EU) and North Atlantic Oscillation (NAO) circulation patterns, which are responsible for large air mass exchanges in the area, being vertically extended in the middle and the lower troposphere. Copyright © 2001 Royal Meteorological Society
Principal modes of interannual and decadal variability of summer rainfall over South America
Authors: Zhou Jiayu , Lau K.‐M.
Published: August 2002

Using the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) product together with the Goddard Earth Observing System (GEOS) reanalysis and the National Center for Environmental Prediction (NCEP) sea‐surface temperature (SST) data, we have conducted a diagnostic study of the interannual and decadal scale variability of principal modes of summer rainfall over South America for the period 1979–1995. By filtering the annual and short (<12 months) time‐scale variations, results of empirical orthogonal function analysis show three leading modes of rainfall variation identified with interannual, decadal and long‐term variability. Together, these modes explain more than half the total variance of the filtered data.

The first mode is highly correlated with El Niño–Southern Oscillation (ENSO), showing a regional rainfall anomaly pattern largely consistent with previous results. This mode captures the summer season interannual variability, not only the Northeast Brazil drought but also its connection with excessive rainfall over Southern Brazil and the Ecuador coast in El Niño years. Another distinctive feature is the strengthening of the low‐level flow along the eastern foothills of the eastern Andes, signifying an enhancement of the South American summer monsoon in response to an El Niño anomaly.

The decadal variation displays a meridional shift of the Inter‐Tropical Convergence Zone (ITCZ), which is tied to the anomalous cross‐equatorial SST gradient over the Atlantic and the eastern Pacific. Associated with this mode is a large‐scale mass swing between polar regions and the mid‐latitudes. Over the South Atlantic and the South Pacific, the anomalous subtropical high and the associated anomalous surface wind are dynamically consistent with the distribution of local SST anomalies, suggesting the importance of atmospheric forcing at the decadal time scale.

The long‐term variation shows that since 1980 there has been a decrease of rainfall from the northwest coast to the southeast subtropical region and a southwards shift of the Atlantic ITCZ, leading to increased rainfall over northern and eastern Brazil. Possible links of this mode to the observed SST warming trend over the subtropical South Atlantic and to the interdecadal SST variation over the extratropical North Atlantic are discussed. Copyright © 2001 Royal Meteorological Society
Statistical downscaling relationships for precipitation in the Netherlands and North Germany
Authors: Beckmann Björn‐R. , Adri Buishand T.
Published: August 2002

The statistical linkage of daily precipitation to the National Centers for Environment Prediction (NCEP) reanalysis data is described for De Bilt and Maastricht (Netherlands), and for Hamburg, Hanover and Berlin (Germany), using daily data for the period 1968–97. Two separate models were used to describe the daily precipitation at a particular site: an additive logistic model for rainfall occurrence and a generalized additive model for wet‐day rainfall. Several dynamical variables and atmospheric moisture were included as predictor variables. The relative humidity at 700 hPa was considered as the moisture variable for rainfall occurrence modelling. For rainfall amount modelling, two options were compared: (i) the use of the specific humidity at 700 hPa, and (ii) the use of both the relative humidity at 700 hPa and precipitable water.

An application is given with data from a time‐dependent greenhouse gas forcing experiment using the coupled ECHAM4/OPYC3 atmosphere–ocean general circulation model for the periods 1968–97 and 2070–99. The fitted statistical relationships were used to estimate the changes in the mean number of wet days and the mean rainfall amounts for the winter and summer halves of the year at De Bilt, Hanover and Berlin. A decrease in the mean number of wet days was found. Despite this decrease, an increase in the mean seasonal rainfall amounts is predicted if specific humidity is used in the model for wet‐day rainfall. This is caused by the larger atmospheric water content in the future climate. The effect of the increased atmospheric moisture is smaller if the alternative wet‐day rainfall amount model with precipitable water and relative humidity is applied. Except for an anomalous change in mean winter rainfall at Hanover, the estimated changes from the latter model correspond quite well with those from the ECHAM4/OPYC3 model.

Despite the flexibility of generalized additive models, the rainfall amount model systematically overpredicts the mean rainfall amounts in situations where extreme rainfall could be expected. Interaction between predictor effects has to be incorporated to reduce this bias. Copyright © 2002 Royal Meteorological Society
Cobalt porphyrins immobilized on niobium(V) oxide grafted on a silica gel surface: study of the catalytic reduction of dissolved dioxygen
Authors: PESSÔA CHRISTIANA A. , GUSHIKEM YOSHITAKA
Published: August 2002

Hematoporphyrin IX, H 2 HMP , 8,13-bis(1-hydroxyethyl)-3,7,12,17-tetramethyl-21 H ,23 H -porphine-2,18-dipropionic acid and protoporphyrin IX, H 2 PP , 8,13-divinyl-3,7,12,17-tetramethyl-21 H ,23 H -porphine-2,18-dipropionic acid were efficiently immobilized on niobium oxide grafted on a silica gel surface, SiO 2/ Nb 2 O 5, by the - COO – Nb bond formed between the porphyrin carboxyl groups and the grafted Nb 2 O 5. These immobilized porphyrins, SiO 2/ Nb 2 O 5/ H 2 HMP and SiO 2/ Nb 2 O 5/ H 2 PP , were further reacted with Co (II) in dimethylformamide, resulting in SiO 2/ Nb 2 O 5/ CoHMP and SiO 2/ Nb 2 O 5/ CoPP metallated complexes. The UV-vis spectra of the solid materials showed changes of the Q-bands ( a 2 u → e g transition) upon metallation, indicating that by incorporation of Co (II) in the porphyrin ring the local symmetry changed from D2 h to D4 h . These materials, when incorporated in carbon paste electrodes, presented the property of electrocatalyzing O 2 reduction. Rotating disk experiments were performed in order to estimate the number of electrons involved in the process. It was observed that, for both modified electrodes, O 2 was reduced to water in a four-electron process. Amperometric studies showed the potentiality of both modified electrodes as sensors for the determination of dissolved dioxygen. The response time was less than 3 s. A linear response for both systems was obtained between 2 and 12 ppm.
How sensitive are river systems to climate and land‐use changes? A model‐based evaluation
Authors: Coulthard T. J. , Macklin M. G.
Published: August 2002

Simulated Holocene sediment discharges from a high‐resolution cellular model of river evolution in northern England, driven by a peat‐bog proxy climate and palynological based land‐cover record, show a very close similarity to alluviation phases evident in British river valleys. Independent validation of the model indicates that British river systems have been surprisingly sensitive to short term (ca. 102 yr) climate fluctuations, although river dynamics also have been modulated by land‐use change and sediment supply. This has important implications for understanding alluvial system evolution, establishing controlling factors and, most importantly, forecasting river response to future climate and land‐use changes. Copyright © 2001 John Wiley & Sons, Ltd.
Late Holocene dinoflagellate cysts as indicators for short‐term climate variability in the eastern Laptev Sea (Arctic Ocean)
Authors: Kunz‐Pirrung Martina , Matthiessen Jens , de Vernal Anne
Published: August 2002

A sediment sequence from the eastern Laptev Sea shelf (Siberian Arctic, Russia) has been studied for dinoflagellate cysts in order to reconstruct sea‐surface conditions during the late Holocene. Variability of assemblage composition and derived sea‐surface temperature estimates indicate that the neoglacial cooling was not a gradual climate change from 2510 to 900 cal. yr BP. Relatively stable conditions, with temperatures that were warmer than today, were punctuated by a few cooling events in summer on centennial time‐scales. During these events temperatures reached modern values. This suggests that modern conditions may have been established abruptly within a short period in the past 1000 yr, which is not documented in our record. Copyright © 2001 John Wiley & Sons, Ltd.
Isotope and disorder effects in the Raman spectra of LiHxD1−x crystals
Authors: Plekhanov V. G.
Published: August 2002

Most of the physical properties of a solid depend on its isotopic composition in some way or another. Scientific interest, technological promise and increased availability of highly enriched isotopes have led to a sharp rise in the number of experimental and theoretical studies with isotopically controlled crystals. A great number of stable isotopes and well‐developed methods for their separation have made it possible to grow crystals of C, LiH, ZnO, ZnSe, CuCl, GaN, GaAs, CdS, Cu2O, Si, Ge and α‐Sn with a controllable isotopic composition. Among these compounds, LiH possesses the largest value of the isotope effect. The great number of theoretical and experimental data suggest that the isotopic composition of a crystal lattice exerts some influence on the vibrational properties of crystals. These effects are fairly large and can be readily measured by modern experimental techniques (ultrasound, Brillouin and Raman scattering and neutron scattering). In addition, crystals of different isotopic compositions possess different Debye temperatures. This difference between an LiH crystal and its deuterated analogue exceeds a 100 K. Very pronounced and general effects of isotopic substitution are observed in phonon spectra. The scattering lines in isotopically mixed crystals are not only shifted (the shift of LO lines exceeds 100 cm−1) but are also broadened. This broadening is related to the isotopic disorder of the crystal lattice. It is shown that the degree of a change in the scattering potential is different for different isotopic mixed crystals. In the case of germanium and diamond crystals, phonon scattering is weak, which allows one to apply successfully the coherent potential approximation (CPA) for describing the shift and broadening of scattering lines. In the case of lithium hydride, the change in the scattering potential is so strong that it results in phonon localization, which is directly observed in experiments. The common nature of the isotopic and disorder effects in a wide range of crystals is emphasized. Copyright © 2001 John Wiley & Sons, Ltd.
Conformational equilibria, Raman and infrared spectra and ab initio calculations of dichloromethylmethyldichlorosilane
Authors: Aleksa V. , Gruodis A. , Powell D. L. , Klaeboe P. , Nielsen C. J. , Guirgis G. A.
Published: August 2002

The infrared spectra of dichloromethylmethyldichlorosilane (Cl2CHCH3SiCl2) were recorded in the vapour, amorphous and partly crystalline phases and when isolated in argon, nitrogen and krypton matrices at 5 K. Raman spectra of the liquid were recorded at various temperatures between 295 and 147 K. Spectra of the amorphous and annealed crystal deposited on a copper finger at 80 K were obtained. The spectra showed the existence of two conformers, anti and gauche, in the vapour and in the liquid. Approximately 12 infrared bands were reduced in intensity, and six of the same bands present in the fluid phases in the Raman spectra vanished upon crystallization. From the intensity variations of two band pairs with temperature, a ΔH° value of 0.4 ± 0.3 kJ mol−1 between the conformers was obtained in the liquid, anti being the low‐energy conformer. Small increases and decreases in the IR band intensities were observed in the matrix spectra after annealing to 32 K (nitrogen), 36 K (argon) and 50 K (krypton). The enthalpy difference between the conformers is low in the matrices, but the anti conformer had lower energy than the gauche conformer. Ab initio calculations were performed at the HF/6–311G* level and gave optimized geometries, vibrational wavenumbers and infrared and Raman intensities for the anti and gauche conformers. The conformational energy derived was 4.4 kJ mol−1 with anti being the low‐energy conformer. The dipole moments were calculated to be 1.2 and 3.1 D for the anti and gauche conformers, respectively. Correlation between the observed and calculated wavenumbers of both conformers revealed that anti was present in the crystal, and complete assignments of the spectra were carried out. Copyright © 2001 John Wiley & Sons, Ltd.
Influence of electrolytes on the structure of cysteamine monolayer on silver studied by surface‐enhanced Raman scattering
Authors: Michota Agnieszka , Kudelski Andrzej , Bukowska Jolanta
Published: August 2002

Monolayers of cysteamine (2‐aminoethanethiol) frequently work in aqueous solutions of electrolytes as linkage layers for adsorption of other molecules on metal surfaces. We determined the influence of various ions on the structure of the cysteamine monolayer with surface‐enhanced Raman scattering (SERS). The surrounding (pH, electrolytes) considerably influences the conformation of adsorbed cysteamine molecules. Direct spectral evidence of the interaction of cysteamine with an Ag surface through AgN bonds in the gauche conformation is given. It was found that chlorides and iodides significantly increase the proportion of the gauche conformer. Probably these anions additionally stabilize the gauche conformer by the formation of hydrogen bonds with NH2 groups in addition to the direct NAg bond. Raman measurements also revealed that cations, which can form strong coordination bonds with amino groups (Cu2+, Ni2+ or Co2+), change the structure of the cysteamine layer by transforming the trans into a gauche conformer. In contrast, an increase in the proportion of trans conformers is observed with increase in the concentration of H+ in the ambient electrolyte. Possible explanations for these experimental findings are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Pre‐resonance Raman excitation profile of the 3400 cm−1 mode of liquid water
Authors: Ahmad S. R. , Iles A.
Published: August 2002

The absolute differential Raman scattering cross‐section of the 3400 cm−1 symmetric vibrational mode of liquid water was measured for the excitation wavelength range 450–200 nm. Available data on the Raman cross‐section are critically reviewed. Although the values obtained by most authors at 488 nm excitation are in good agreement, the values are widely different for a few other reported excitation wavelengths. Direct comparison of these results with those measured in this work is not strictly valid owing to the large differences in experimental procedures and methods of data analysis. The excitation wavelength dependence of the Raman cross‐section (excitation profile) was fitted to a single‐term Albrecht A‐term pre‐resonance approximation formula (AATPA). A best fit was obtained for the value of the resonant state, νe = 89 100 cm−1 and the coupling constant, K = 39.2 × 10−27 cm2 (integrated). The data show consistent lower (than predicted) values for wavelengths down to about 220 nm and higher values below this. The imponderable errors in the implementation of corrections at very short wavelengths could well have given rise to a systematic error in this excitation wavelength region. Copyright © 2001 John Wiley & Sons, Ltd.
Structural effects on the vibrational behaviour of N,N′‐Diphenyl‐1,4‐phenylenediamine
Authors: Mevellec J.‐Y. , Quillard S. , Boyer M. I. , Buisson J.‐P.
Published: August 2002

A vibrational study of two crystalline forms of the N,N′‐diphenyl‐1,4‐phenylenediamine molecule is reported. This compound shows polymorphism in its solid state, i.e. either an orthorhombic or a triclinic structure is obtained depending on the conditions of crystallization. Three conformational isomers are evidenced in these structures, showing significant differences between their geometric parameters, especially their torsional angles. These observations are also supported by the vibrational features characteristic of the conformers in the crystals. Several changes are observed in the infrared absorption (ir) and Raman scattering data. This work concerns mainly the polarized Raman measurements on these two crystalline forms. A detailed analysis and a good knowledge of phenyl compounds allow a very precise assignment of the vibrational modes and also reveals the structure–properties (especially molecular conformations–vibrational properties) relationships in these systems. In particular, the effect of the crystalline arrangement and of the local symmetry between neighbouring molecules is discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Pseudo gap and its relation to anomalous features in underdoped Bi2212
Authors: Machtoub L. H. , Robinson L. , Shimoyama J. , Suemoto T. , Kishio K.
Published: August 2002

We report detailed resonance Raman investigations of the pseudo gap and the anomalous modes observed in underdoped Bi2Sr2CaCu2O8±δ. We observed similarity in the resonance profiles of the B1g 600 cm−1 peak and the A1g 630 cm−1 phonon mode, which provides strong evidence for the origin of the 600 cm−1 feature to be in some part a vibrational mode. At low temperatures we observed an increase in intensity in the feature and depletion in spectral weight. We attribute the origin of the anomalous feature to two independent components, vibrational and electronic, with coincidental overlapping. Copyright © 2001 John Wiley & Sons, Ltd.
Simultaneous preparation of SERS‐active metal colloids and plates by laser ablation
Authors: Lee Inhyung , Han Sang Woo , Kim Kwan
Published: August 2002

We prepared Ag and Au colloids by laser ablation of pure metals in water. The colloids were stable for several weeks without any extra stabilizing agents. Surface‐enhanced Raman scattering (SERS) spectra could be obtained reproducibly using these metal colloids. In addition, the SERS enhancement factors on these colloids were comparable to those on chemically prepared colloids. After the laser ablation, roughened features with holes and irregular protrudes were observed in the remaining metal plates. The roughness of the laser‐ablated plate increased as the laser pulse energy increased. The SERS spectral measurements showed that the remaining metal plate after the laser ablation could also be used as an efficient and reproducible SERS‐active substrate. Copyright © 2001 John Wiley & Sons, Ltd.
Fluorescence background suppression in Raman spectroscopy using combined Kerr gated and shifted excitation Raman difference techniques
Authors: Matousek P. , Towrie M. , Parker A. W.
Published: August 2002

An exceptionally high level of fluorescence rejection from resonance Raman spectra was achieved using a combination of two techniques, namely Kerr gated temporal rejection with shifted excitation Raman difference spectroscopy. The method was able to recover the resonance Raman spectrum from the intense fluorescence background with a signal‐to‐noise ratio at least 10 times higher than that achievable with either of the two approaches used individually. To demonstrate the effectiveness of the technique we obtained the resonance Raman spectrum of the laser dye rhodamine 6G (1 × 10−3 mol dm−3) in methanol by excitation at 532 nm and measuring under the maximum of fluorescence emission at 560–590 nm. The method reached the photon shot noise limit of the residual fluorescence providing a detection limit for Raman spectra 106 times lower than the original fluorescence intensity in an accumulation time of 800 s. A unique feature of the experiment was the way in which the optical parametric amplifier light source was configured to alternate automatically between the two excitation wavelengths using an optogalvanic mirror arrangement. The ultra‐high sensitivity of the combined approach holds great promise for selective probing of complex biological systems using resonance Raman spectroscopy. Copyright © 2002 John Wiley & Sons, Ltd.
Climbing Bridalveil Falls: organization change, process and re‐engineering
Authors: Collins David
Published: August 2002

This paper offers a metaphorical analysis of organization change, which argues that our understanding of the problems and processes of change reflects a representation of a fluxing reality, frozen by limiting assumptions.

In an attempt to break free from these restrictive assumptions the paper sets out to encourage readers to re‐imagine change in a qualitatively different manner—as the essence of organization.

Offering a comparative analysis of the contributions, the paper argues that the more conservative contribution offered by the latter offers a more faithful appreciation of the complexities of organization change.

Copyright © 2002 John Wiley & Sons, Ltd.
Cell wall polysaccharides of bush butter (Dacryodes edulis (G Don) HJ Lam) fruit pulp and their evolution during ripening
Authors: Missang Crépin Ella , Renard Cathérine M G C , Baron Alain , Drilleau Jean‐François
Published: August 2002

Cell wall material was isolated as alcohol‐insoluble solids (AIS) from bush butter endocarp tissue at different stages of ripeness. AIS were then extracted with 0.05 M CDTA followed by increasing concentrations of KOH (0.05, 1 and 4 M respectively). The chemical extractions solubilised a total of 51.6–60.6% of AIS, the yields of CDTA extracts accounting for approximately 9.6–12.2% of AIS. The extracts as well as the residues were analysed for their sugar composition and protein and starch contents. CDTA extracted the bulk of uronic acid in AIS, but the uronic acid content (after dialysis) of these extracts showed a significant decrease as the fruits ripened (from 439 to 252 mg g−1 between the first and the last degree of ripeness). Analysis of the CDTA extracts by anion exchange and size exclusion chromatography showed a gradual appearance of new pectic populations at low degrees of methylation and low molecular weights, indicating that CDTA‐soluble pectins are demethylated and depolymerised during ripening. The dilute alkali (0.05 M KOH) extracts were essentially composed of proteins in addition to a minor quantity of pectin. The 1 M KOH and principally 4 M KOH treatments led to the extraction of hemicelluloses, mainly xyloglucan‐like and mannan‐like polymers. These extracts also contained substantial amounts of protein and starch. No variation related to the degree of ripeness was visible in the sugar composition of the alkali extracts. The molecular weight distribution of the hemicelluloses did not change with the degree of ripeness. The final residues accounted for 21.4–27.3% of AIS and were mostly composed of glucose (827–908 mg g−1). All these results suggested that only CDTA‐soluble pectins were involved in bush butter fruit softening.

© 2001 Society of Chemical Industry
Fermentation characteristics, aerobic stability and ruminal degradation of ensiled pea/wheat bi‐crop forages treated with two microbial inoculants, formic acid or quebracho tannins
Authors: Salawu Mustapha B , Warren Elizabeth H , Adesogan Adegbola T
Published: August 2002

This study evaluated the effects of two commonly used microbial inoculants (Lactobacillus buchneri (LB) and Lactobacillus plantarum (LP)), formic acid (FA) and quebracho tannins (QT) on the fermentation quality, aerobic stability and in situ rumen degradation of pea/wheat bi‐crop forages. Precision‐chopped spring pea (Pisum sativum, var Magnus) and wheat (Triticum aestivum, var Axona) bi‐crops (3:1 pea/wheat ratio) harvested at a combined dry matter (DM) content of 301 g kg−1 were used for the study. The bi‐crops were conserved without (Control) or with inoculants based on lactic acid bacteria (LB (105 CFU g−1 fresh weight (FW)) or LP (106 CFU g−1 FW)), QT (16 g kg−1 FW) or FA (2.5 g kg−1 FW) in laboratory silos of 1.5 kg capacity, with each treatment being replicated six times. The pH, chemical composition, aerobic stability and in situ rumen degradation of DM, nitrogen (N) and neutral detergent fibre (NDF) after 112 days of ensilage were measured. The average pH at silo opening was 4.0, suggesting that the silages were well fermented. There were no significant effects of additive treatment on water‐soluble carbohydrate, total N, soluble N, ammonia N and NDF. Lactic acid and acetic acid were the main fermentation products. High concentrations of acetic acid were found in all the treatments, indicating a heterofermentative pathway. Although FA treatment gave the most aerobically stable silage, the Control and QT‐treated silages did not heat up by more than 1 °C until after 6 days of exposure to air. There were no effects of additives on DM degradation characteristics. However, the inoculants increased the rate of N and NDF degradation in the rumen, and both FA and QT reduced the effective and potential degradation of N.

© 2001 Society of Chemical Industry
Adhesion molecules in human pancreatic cancer*
Authors: Tempia‐Caliera Adrien A. , Horvath Laszlo Zs. , Zimmermann Arthur , Tihanyi Tibor T. , Korc Murray , Friess Helmut , Büchler Markus W.
Published: August 2002

Background and Objectives

Adhesion molecules are cell surface glycoproteins that are important in cell‐to‐cell and cell‐to‐extracellular matrix interactions. In the present study, we analyzed the adhesion molecules ICAM‐1 (intercellular adhesion molecule‐1), VCAM‐1 (vascular cell adhesion molecule‐1), and ELAM‐1 (endothelial leukocyte adhesion molecule‐1) in human pancreatic cancer.

Methods

ICAM‐1, VCAM‐1, and ELAM‐1 were analyzed in 20 pancreatic cancer specimens and 20 normal pancreatic tissues. mRNA expression encoding ICAM‐1, VCAM‐1, and ELAM‐1 was assessed with Northern blot analysis. The distribution and localization of ICAM‐1, VCAM‐1, and ELAM‐1 was determined in the pancreatic specimens by immunohistochemistry.

Results

Northern blot analysis revealed a 5.4‐fold increase of ICAM‐1 (P < 0.01) and a 3.7‐fold increase in VCAM‐1 (P < 0.01) mRNA expression in cancer samples in comparison with normal controls. In contrast, ELAM‐1 mRNA levels did not show significant differences between the cancer and the normal tissues. Immunohistochemical analysis of cancer tissues showed strong immunostaining for ICAM‐1 and VCAM‐1, and faint immunostaining for ELAM‐1 in the pancreatic cancer cells. Fibrotic or noncancerous pancreatic tissue adjacent to the cancer mass was devoid of any immunoreactivity for ICAM‐1, ELAM‐1, and VCAM‐1. In contrast, the normal pancreas exhibited no immunoreactivity of ICAM‐1, ELAM‐1, and VCAM‐1.

Conclusions

Enhanced expression of ICAM‐1 and VCAM‐1 in human pancreatic cancers suggests a role in tumor pathogenesis. The increase of these adhesion molecules might influence the detachment of cancer cells in the primary tumor, might contribute to cancer cell migration and the spread of cancer cells to distant organs, or both. J. Surg. Oncol. 2002;79:93–100. © 2002 Wiley‐Liss, Inc.