bluuebunny/crossref_metadata_2025_split huggingface dataset:
NMR Investigation of the Dihydrogen‐Bonding and Proton‐Transfer Equilibria between the Hydrido Carbonyl Anion [HRe2(CO)9]− and Fluorinated Alcohols
Authors: Donghi Daniela , Beringhelli Tiziana , D'Alfonso Giuseppe , Mondini Marta 
Published: November 2005

AbstractThe interaction of fluorinated alcohols with the anionic hydrido complex [HRe2(CO)9]− (1) has been investigated by NMR spectroscopy. According to the acidic strength of the alcohols, the interaction may result not only in the formation of dihydrogen‐bonded ROH⋅⋅⋅[HRe2(CO)9]− adducts 2, but also in proton transfer to give the neutral species [H2Re2(CO)9] (3). With the weaker acid trifluoroethanol (TFE) evidence for the occurrence of the dihydrogen‐bonding equilibrium was obtained by 2D 1H NOESY. The dependence of the hydride chemical shift on TFE concentration at different temperatures provided values for the constants of this equilibrium, from which the thermodynamic parameters were evaluated as ΔH°=−2.6(2) kcal mol−1, ΔS°=−9.3(2) cal mol−1 K−1. This corresponds to a rather low basicity factor (Ej=0.64). Variable‐temperature T1 measurements allowed the proton–hydride distance in adduct 2 a to be estimated (1.80 Å). In the presence of hexafluoroisopropyl alcohol (HFIP) simultaneous occurrence of both dihydrogen‐bonding and proton‐transfer equilibria was observed, and the equilibria shifted versus the protonated product 3 with increasing HFIP concentration and decreasing temperature. Reversible proton transfer between the alcohol and the hydrido complex occurs on the NMR timescale, as revealed by a 2D 1H EXSY experiment at 240 K. For the more acidic perfluoro‐tert‐butyl alcohol (PFTB) the protonation equilibrium was further shifted to the right. Thermal instability of 3 prevented the acquisition of accurate thermodynamic data for these equilibria. The occurrence of the proton‐transfer processes (in spite of the unfavorable pKa values) can be explained by the formation of homoconjugated RO⋅⋅⋅HOR− pairs which stabilize the alcoholate anions.
Water Dynamics in Ionomer Membranes by Field‐Cycling NMR Relaxometry
Authors: Perrin J.‐C. , Lyonnard S. , Guillermo A. , Levitz P. 
Published: November 2005

AbstractThe water dynamics of two types of ionomer membranes, the Nafion® and sulfonated polyimides, have been investigated by field‐cycling nuclear magnetic relaxation. This technique, applied to samples prepared at different water content, allows to characterize the proton motion at the time scale of the microsecond. The polyimides appear to behave as standard porous materials, whereas in the Nafion®, we have observed two different dynamical regimes related to a complex swelling process.
Non Linear State Space Modelling of a PEMFC
Authors: Hernandez A. , Hissel D. , Outbib R. 
Published: November 2005

AbstractThis paper will present a reduced input non linear state space model which describes the dynamic performance of a Proton Exchange Membrane air‐hydrogen fuel cell (PEMFC). The mathematical model is based mainly on gases physical behaviour, which leads to reactants partial pressure evolution within the channels. In order to obtain a more realistic model, liquid water formation within the fuel cell channels; and its influence on the fuel cell voltage is considered from a probabilistic approach. Model simulations under dynamic charge conditions are validated using results obtained from experiments done with a 500 W fuel cell existing in our laboratory (L2ES).
Technological advances in MRI measurement of brain perfusion
Authors: Duyn Jeff H. , van Gelderen Peter , Talagala Lalith , Koretsky Alan , de Zwart Jacco A. 
Published: November 2005

AbstractMeasurement of brain perfusion using arterial spin labeling (ASL) or dynamic susceptibility contrast (DSC) based MRI has many potential important clinical applications. However, the clinical application of perfusion MRI has been limited by a number of factors, including a relatively poor spatial resolution, limited volume coverage, and low signal‐to‐noise ratio (SNR). It is difficult to improve any of these aspects because both ASL and DSC methods require rapid image acquisition. In this report, recent methodological developments are discussed that alleviate some of these limitations and make perfusion MRI more suitable for clinical application. In particular, the availability of high magnetic field strength systems, increased gradient performance, the use of RF coil arrays and parallel imaging, and increasing pulse sequence efficiency allow for increased image acquisition speed and improved SNR. The use of parallel imaging facilitates the trade‐off of SNR for increases in spatial resolution. As a demonstration, we obtained DSC and ASL perfusion images at 3.0 T and 7.0 T with multichannel RF coils and parallel imaging, which allowed us to obtain high‐quality images with in‐plane voxel sizes of 1.5 × 1.5 mm2. J. Magn. Reson. Imaging 2005. Published 2005 Wiley‐Liss, Inc.
Quantification of cerebral perfusion using arterial spin labeling: Two‐compartment models
Authors: Parkes Laura M. 
Published: November 2005

AbstractOne of the advantages of arterial spin labeling (ASL) techniques over other techniques for measuring cerebral perfusion is that with ASL it is possible to achieve accurate quantification. This is particularly useful in the field of functional imaging, where accurate measurements of perfusion change can help untangle the complex physiological changes that occur following neuronal activation. However, the linearity of the perfusion estimate over a wide range of perfusion values may be more important than absolute values. For several years, single‐compartment models have dominated the literature, and it has been assumed that the labeled water diffuses freely throughout the tissue voxel. However, recent work, as summarized in this review, has shown that this assumption is inaccurate and leads to an overestimation of perfusion at low perfusion rates, and an underestimation at high rates. The inclusion of restricted permeability of the capillary wall to water in a two‐compartment model offers improved quantification. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.
Perfusion‐based fMRI: Insights from animal models
Authors: Silva Afonso C. 
Published: November 2005

AbstractModern functional neuroimaging techniques, including functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and optical imaging of intrinsic signals (OIS), rely on a tight coupling between neural activity and cerebral blood flow (CBF) to visualize brain activity using CBF as a surrogate marker. Because CBF is a uniquely defined physiological parameter, fMRI techniques based on CBF contrast have the advantage of being specific to tissue signal change, and the potential to provide more direct and quantitative measures of brain activation than blood oxygenation level‐dependent (BOLD)‐ or cerebral blood volume (CBV)‐based techniques. The changes in CBF elicited by increased neural activity are an excellent index of the magnitude of electrical activity. Increases in CBF are more closely localized to the foci of increased electrical activity, and occur more promptly to the stimulus than BOLD‐ or CBV‐based contrast. In addition, CBF‐based fMRI is less affected by confounds from venous drainage common to BOLD. Animal studies of brain activation have yielded considerable insights into the advantages of CBF‐based fMRI. Based on results provided by animal studies, CBF fMRI may offer a means of better assessing the magnitude, spatial extent, and temporal response of neural activity, and may be more specific to tissue state. These properties are expected to be particularly useful for longitudinal and quantitative fMRI studies. J. Magn. Reson. Imaging 2005. Published 2005 Wiley‐Liss, Inc.
The effect of chronic inflammatory condition of the bladder and estrogen replacement therapy on bladder functions and histology in surgically menopause and chronic cystitis induced rats
Authors: Çayan Selahittin , Canpolat Bülent , Çayan Filiz , Yιlmaz Necat , Kartal Akif , Oǧuz İzzet , Akbay Erdem 
Published: November 2005

AbstractAimsWe investigated the effect of chronic inflammatory condition of the bladder and estrogen replacement therapy on bladder function and histological changes in surgically menopause and chronic cystitis induced rats.MethodsThe study included 36 female Sprague–Dawley rats, divided into five groups. After bilateral ovariectomy, chronic cystitis was induced by intravesical instillation of HCl, and then group 1 (n = 8) received nasal estrogen, and group 2 (n = 8) received oral estrogen replacement therapy. Group 3 (n = 7) underwent ovariectomy and chronic cystitis, but no replacement therapy. Group 4 (n = 7) had only ovariectomy. Group 5 (n = 6) was taken as sham group. The rats were sacrificed after 60 days, and cystometric study and histological findings were compared among the groups.ResultsThe mean maximal bladder capacity and compliance revealed significant decreases in group 3 and 4 compared with group 5, and significant increases in group 1 and 2 compared with group 3. Histological findings showed significant increases in the mast cells and leukocyte infiltration of group 3 and 4 compared with group 5, and significant decreases in the mast cells and leukocyte infiltration of group 1 and 2 compared with group 3.ConclusionsThis experimental menopause and chronic cystitis model showed that bladder function and histology might deteriorate much more with chronic cystitis in postmenopausal period. This is the first study in the literature to report that chronic inflammatory bladder occurring after menopause can be improved by estrogen replacement therapy. Neurourol. Urodynam. © 2005 Wiley‐Liss, Inc.
Free convection and radiation characteristics for a vertical plate embedded in a porous medium
Authors: Badruddin Irfan Anjum , Zainal Z. A. , Aswatha Narayana P. A. , Seetharamu K. N. , Siew Lam Weng 
Published: November 2005

AbstractSteady two‐dimensional free convection flow due to combined effect of radiation and convection through a porous medium bounded by a vertical infinite plate is considered. The behaviour of Darcy and non‐Darcy flow is investigated. The flow of water through different porous media under different environmental conditions is discussed. Effect of four non‐dimensional parameters, i.e. Prandtl number (Pr), modified Grashof number (G), permeability parameter (K) and radiation parameter (N) has been studied. Effect of these parameters on Nusselt number is analysed. Copyright © 2005 John Wiley & Sons, Ltd.
Polyaniline nanotubes: conditions of formation
Authors: Konyushenko Elena N , Stejskal Jaroslav , Šeděnková Ivana , Trchová Miroslava , Sapurina Irina , Cieslar Miroslav , Prokeš Jan 
Published: November 2005

AbstractThe courses of aniline oxidation with ammonium peroxydisulfate in aqueous solutions of strong (sulfuric) and in weak (acetic) acids, followed by temperature and acidity changes, are different. In solutions of sulfuric acid, granular polyaniline (PANI) was produced; in solutions of acetic acid, PANI nanotubes were obtained. The external diameter of the nanotubes was 100–300 nm, the internal cavity 20–100 nm, and the length extended to several micrometres. The morphology of PANI, granular or tubular, depends on the acidity conditions during the reaction rather than on the chemical nature of the acid. PANI nanotubes were also produced when aniline was oxidized in the absence of any acid. The bulk conductivity of PANI prepared in solutions of acetic acid was 0.08–0.27 S cm−1, depending on the acid concentration. Protonated PANI prepared in sulfuric and acetic acids were deprotonated with ammonium hydroxide to obtain PANI bases and the ammonium salt of the protonating acid. FTIR spectroscopy showed the differences in the molecular structure of the PANI bases. Irrespective of whether the polymerization was performed in solutions of sulfuric or acetic acid, PANI had hydrogen sulfate counter‐ions only. The PANI morphology is thus not controlled by the nature of counter‐ions. The acidity of the reaction medium determines the protonation of monomer, oligomer and polymer species. The chemistry of aniline oxidation is likely to be affected especially by the protonation of an intermediate in the pernigraniline form. It is proposed that, in the course of aniline oxidation, pH‐dependent self‐assembly of aniline oligomers predetermines the final PANI morphology. Copyright © 2005 Society of Chemical Industry
Dexamethasone has pro‐apoptotic effects on non‐activated fresh peripheral blood mononuclear cells
Authors: Totino Paulo Renato Rivas , Riccio Evelyn Kety Pratt , Corte‐Real Suzana , Daniel‐Ribeiro Cláudio Tadeu , Ferreira‐da‐Cruz Maria de Fátima 
Published: November 2005

AbstractApoptosis is a physiological method of cell death commonly referred to as programmed cell death. However, non‐apoptotic programmed cell death, such as autophagy and programmed necrosis, has been characterized by morphological criteria. In view of the human therapeutic use of DEX, and considering that no difference in the number and/or affinity of glucocorticoid receptors in activated and non‐activated lymphocytes has been reported, we decided to evaluate the effect of DEX on fresh peripheral blood mononuclear cells (PBMC). Transmission electron microscopy showed that DEX can significantly induce apoptosis in non‐activated PBMC. It was also observed by transmission electron microscopy that, independently of DEX treatment, PBMC also died by a process marked by extreme vacuolization and increase in cellular volume; these cells were erroneously classified as viable by flow cytometry using the 7‐AAD assay. It is concluded that the DEX pro‐apoptotic effect is not restricted to activated PBMC and, therefore, DEX‐induced apoptosis could play either homeostatic (activated PBMC) or immunosuppressive (non‐activated PBMC) roles.
Stimulative effects of insulin on Toxoplasma gondii replication in 3T3‐L1 cells
Authors: Zhu Sha , Lai De‐Hua , Li San‐Qiang , Lun Zhao‐Rong 
Published: November 2005

AbstractThe influence of insulin and 2‐deoxy‐glucose (d‐glucose) on the intracellular protozoan Toxoplasma gondii replication in 3T3‐L1 cells was investigated. Insulin and d‐glucose had a dose‐responsive mitogenic effect on intracellular T. gondii replication and development in 3T3‐L1 cells. Insulin concentrations between 10−2 and 10−1 μg/ml combination of 4.5 g/l d‐glucose in DMEM medium gave maximum stimulus to T. gondii replication. The number of tachyzoites increased rapidly, with the growth peaking typically on day 3 or 4 of culture, and then declining quickly. However, insulin, in the absence of d‐glucose, had comparably less effect on T. gondii growth than two of their combination. d‐glucose concentrations significantly affected the tachyzoite replication and appear to be indispensable for maintaining the host 3T3‐L1 cells.
Clinical determinants of poor six‐minute walk test performance in patients with left ventricular systolic dysfunction and no major structural heart disease
Authors: Ingle L. , Rigby A.S. , Nabb S. , Jones P.K. , Clark A.L. , Cleland J.G.F. 
Published: November 2005

AbstractBackground:The clinical determinants of six‐minute walk test (6‐MWT) performance in patients with left ventricular systolic dysfunction (LVSD) have rarely been investigated, and it is not clear whether they differ from patients referred for the assessment of symptoms of heart failure who do not have major structural heart disease (MSHD).Methods and Results:571 patients with LVSD enrolled in a chronic disease management programme (79% male; mean age 71±10 years; BMI 28±5) completed a 6‐MWT with a mean distance 337±103 m. 688 patients referred with suspected heart failure but in whom MSHD was excluded (49% male; mean age 70±11 years; BMI 28±6) had a mean 6‐MWT distance of 391±106 m (P<0.001 compared to patients with LVSD). Relationships with walking distance were determined by calculating odds ratios (ORs) with 95% confidence intervals (CIs) for walking ≤300 versus >300 m. In patients with LVSD, predictors of poor walking distance (≤300 m) included age ≥75 years (OR=4.0, 95% CI=2.4–6.4); low BMI (<20) (OR=3.4, 95% CI=1.6–7.3); anaemia (OR=2.8, 95% CI=1.8–4.2); resting heart rate >80 beats min−1 (OR=2.2, 95% CI=1.3–3.5); and being female (OR=2.0, 95% CI=1.3–3.0). Serum creatinine and NT‐proBNP showed dose–response effects, as did self‐perceived feelings of depression and anxiety. Determinants of 6‐MWT in patients without MSHD were similar including age ≥75 years (OR=6.0, 95% CI=3.4–10.4), anaemia (OR=2.8, 95% CI=1.6–4.9), resting HR >80 beats min−1 (OR=2.5, 95% CI=1.4–4.4) and being female (OR=1.6, 95% CI=1.9–2.4). NT‐proBNP and self‐perceived feelings of depression and anxiety also showed dose–response effects.Conclusion:The determinants of poor 6‐MWT performance depend on physical–cardiovascular and non‐cardiovascular, and psychological factors. Clinical predictors for poor walking performance are similar for patients with LVSD and without MSHD.
The target strength of Antarctic krill (Euphausia superba) measured by the split-beam method in a small tank at 70 kHz
Authors: Amakasu Kazuo , Furusawa Masahiko 
Published: November 2005

Abstract
The target strengths (TS) of Antarctic krill (Euphausia superba) were measured at 70 kHz aboard the research and training vessel “Umitaka-maru” of Tokyo University of Marine Science and Technology in February 2003 during a Southern Ocean survey. The systematic variations of TS vs. the incident angle of the ensonified wave, henceforth called TS-patterns, were successfully measured for 12 live Antarctic krill. These measurements were compared with the theoretical TS-patterns predicted by the Distorted-Wave Born Approximation-based deformed-cylinder model (DWBA model). While there was good agreement near the main lobe, the measurements were higher than the model predictions in the side-lobe regions; this is consistent with the observations of others. Several possible causes of this discrepancy such as the bending of abdomen and scattering from pleopods were examined, but no single factor was identified as the cause. Rather, it is likely that the discrepancy is a result of a combination of several factors.
Reproductive biology and abundance of the white-dotted skate, Bathyraja albomaculata, in the Southwest Atlantic
Authors: Ruocco Natalia L. , Lucifora Luis O. , Díaz de Astarloa Juan M. , Wöhler Otto 
Published: November 2005

AbstractSize at maturity, sexual dimorphism, gonad development, and abundance of white-dotted skate, Bathyraja albomaculata, were assessed along its geographic range in the Southwest Atlantic, from Uruguay to Tierra del Fuego (Argentina). In all, 291 specimens from eight research cruises conducted between 1998 and 2003 were examined. Length–mass relationships were sexually dimorphic, adult females being significantly heavier than males of the same length. The largest female observed was 762 mm total length (LT), and 50% maturity (LT50) was attained at 653 mm LT. The largest male was 732 mm LT, and male LT50 was 628 mm LT. Female and male LT50 were not significantly different and were about 86% of observed maximum size, similar to other Bathyraja species. The lack of sexual dimorphism in size at maturity and the slight difference in maximum size between sexes support the hypothesis of relaxation of selection for large female size in oviparous elasmobranchs. Liver size was not sexually dimorphic. Mature female gonads were symmetrical in terms of mass, and similar in ovarian follicle number and size. Females carried egg cases in April, September, and October, consistent with previous observations around the Islas Malvinas and suggesting year-round egg laying. Bathyraja albomaculata was most abundant on the outer continental shelf and slope between 36°30′S and 45°S (northern area). In contrast, it was generally absent between 48°S and 52°S (southern area), a region where it was formerly reported as abundant. These differences are coincident with the development of a fishery targeting skates in the southern area, whereas in the north B. albomaculata taken as bycatch are mostly discarded alive.
Histological analysis invalidates macroscopically determined maturity ogives of the Kattegat cod (Gadus morhua) and suggests new proxies for estimating maturity status of individual fish
Authors: Vitale F. , Svedäng H. , Cardinale M. 
Published: November 2005

Abstract
Assessment and management of fish populations currently rely on correct estimation of the spawning-stock biomass (SSB), which is based on accurate maturity ogives of the population. Although maturity ogives are usually calculated through macroscopic evaluation of the gonads, histology is generally considered to be more accurate. Here we show that the macroscopic analysis consistently overestimates the proportion of mature females for all age classes in Kattegat cod. The resulting bias showed minimum values for all age classes about a month before the spawning season. Consequently, estimation of the incidence of maturation in females several months before or after the spawning season can only be accurate using histological techniques. Further, the observed bias was used to reconstruct a historical data set of maturity ogives of Kattegat cod. The results showed that female spawning biomass (FSB) might have been overestimated by up to 35%. However, as histological analysis is considered a laborious procedure, proxies of maturity status were sought. It was indicated that the gonadosomatic and hepatosomatic indices may serve as robust proxies for discriminating mature females from immature, thus greatly enhancing the accuracy of the macroscopic maturity evaluation of cod gonads when histological analysis is lacking.
Attitudes toward the discontinuation of female genital cutting among men and women in Guinea
Authors: Gage A.J. , Van Rossem R. 
Published: November 2005

AbstractObjectiveTo investigate socioeconomic correlates of and gender differences in attitudinal support for the discontinuation of FGC in Guinea.MethodData from structured interviews of men aged 15–59 and women aged 15–49 years in the 1999 Demographic and Health Survey and multiple logistic regression methods were used to examine the relationship of socioeconomic factors and gender to attitudinal support for the discontinuation of FGC.ResultMore than 9 out of 10 women had undergone FGC. Attitudinal support for FGC discontinuation was more prevalent among men than women. The odds of supporting the discontinuation of FGC were negatively related to beliefs in social approval of and religious support for FGC and its enhancement of women's marriageability, the number of perceived advantages of FGC, and women's low socioeconomic status.ConclusionCommunity education, improvements in women's socioeconomic status and traditional and religious leader involvement would be critical for FGC eradication.