bluuebunny/crossref_metadata_2025_split huggingface dataset:
The oxidation of uranium(IV) ions by nitrous acid in 30% tri-butyl phosphate
Authors: Koltunov V. S. , Taylor Robin J. , Marchenko V. I. , Savilova O. A. , Dvoeglazov K. N. 
Published: July 2004

SummaryThe kinetics of the oxidation of U(IV) ions by nitrous acid in a 30% TBP solution have been determined. The rate equation was found to be:-d[U(IV)]/dt=k2a([U(IV)][HNO2][HNO3][H2O])/([HNO3]2+β3[HNO3][H2O]+β4[H2O]2),where,k2a=0.405±0.055 M-1min-1at 55 °C (β3≈0.08;β4≈0.007) and the activation energy wasE=112±17 kJ mol-1. The reaction mechanism appeared to involve interaction with the 1sthydrolysis product of U(IV)–UOH3+. The data is compared with a previous study of the nitric acid oxidation of U(IV) in 30% TBP. This reaction is autocatalytic due to the formation of nitrous acid during the reaction. The kinetics of the decomposition of HNO2in 30% TBP (in the absence of U(IV)) have also been reported.
Anion-exchange behavior of Mo and W as homologs of Sg (element 106) in HCl and HNO3 as well as in mixed HCl-HF and HNO3-HF solutions
Authors: Kronenberg A. , Mohapatra P. K. , Kratz Jens Volker , Pfrepper G. , Pfrepper R. 
Published: July 2004

Summary
We have determined K
d values for Mo and W in batch experiments on various anion-exchange resins in HCl and HNO3 as well as in mixed HCl-HF and HNO3-HF solutions in order to create a data base and to select optimum conditions for the determination of K
d values of Sg (element 106) in a future on-line experiment using continuous chromatography with the multi-column technique (MCT). Their influence by hydrolysis and fluoride complexation is discussed and the average charge of the complexes is determined from slope analyses. It is shown that the selectivity of anion exchangers for the Mo- and W complexes and, thus, the separation factors between them, depend strongly on the choice of the functional group of the anion-exchange resin.
Determination of trace element concentration in infant head hair of Rawalpindi/Islamabad area using INAA technique
Authors: Zaidi Jamshed H. , Gill K. P. 
Published: July 2004

Summary
The concentration of 18 minor and trace elements (essential, toxic and nonessential) in infant head hair was determined. The data provide the base-line values of these elements in head hair of infants of low- and medium-income group subjects. The statistical results show that there are significant correlations between some elements such as: Ca-Zn, Ca-Fe, Mg-Ca, Mg-Mn and Mg-Fe. The results obtained have been compared with the data reported in the literature. Our data show compatibility of elemental contents of infant head hair with those from some of the other geological regions but also deviate in some cases.
Habitat Use by Middle Mississippi River Pallid Sturgeon
Authors: Hurley Keith L. , Sheehan Robert J. , Heidinger Roy C. , Wills Paul S. , Clevenstine Bob 
Published: July 2004

AbstractLittle is known about the habitat preferences and needs of pallid sturgeon Scaphirhynchus albus, which was federally listed as endangered in 1990. To learn more about habitat use and selection by pallid sturgeon, sonic transmitters were surgically implanted in 27 individuals from the middle Mississippi River. Study fish were located 184 times (1–23 times/individual) from November 1995 to December 1999. Of the seven macrohabitats identified, pallid sturgeon were found most often in main‐channel habitats (39% of all relocations) and main‐channel border habitats (26%); the between‐wing‐dam habitats were used less often (14%). Strauss's linear selectivity index (Li) values indicated that study fish exhibited positive selection for the main‐channel border, downstream island tips, between‐wing‐dam, and wing‐dam‐tip habitats; they showed negative selection for main‐channel, downstream of wing dams, and upstream of wing dam habitats. Comparison of Li values for four temperature ranges and three daily mean discharge ranges revealed little change in habitat selection due to temperature or discharge. Habitat use patterns also were similar across seasons and discharge regimes, except during spring months when between‐wing‐dam habitats saw greater use and main‐channel and main‐channel border habitat use declined. These changes may have been a response to high river stages associated with spring flooding, which may create favorable feeding areas in the between‐wing‐dam habitats. Enhancement and restoration of habitat diversity, particularly downstream island tip and between‐wing‐dam habitats, may be necessary for the recovery of pallid sturgeon in the middle Mississippi River.
Fundamentgestaltung und Sohlspannungsberechnung mit Optimierungsmethoden und Tabellenkalkulation
Authors: Mark Peter 
Published: July 2004

AbstractEs werden Optimierungsaufgaben aus den Gleichgewichtsbeziehungen zwischen einwirkenden Schnittgrößen und widerstehenden Sohlspannungen sowie Geometrie‐ und Spannungsrandbedingungen formuliert, um Fundamentflächen in Abhängigkeit von gegebenen Einwirkungen und veränderbaren Geometriefreiwerten bestmöglich in Form, Größe und Lage einzustellen. Die Optimierungsaufgaben werden mit praxisüblichen Tabellenkalkulationsprogrammen unter Verwendung numerischer Optimierungsverfahren und numerischer Integration der innerhalb der Gleichgewichtsbeziehungen enthaltenen Flächenintegrale gelöst. Ein Beispiel zeigt die praktische Anwendung.
Comparison of Fixed and Fluidized Activated Carbon Beds for Removal of Organic Vapors
Authors: Agranovski I.E. , Moustafa S. , Braddock R.D. 
Published: July 2004

AbstractActivated carbons are commonly used for removal of organic vapors from exhaust air streams. Two configurations, including fixed and fluidized carbon beds are usually employed in industry to meet various requirements of the industrial process which is being used. This paper investigates the performance of such configurations and provides a comparative analysis. It was found that for thin carbon layers, the fixed bed performs more efficiently with the difference exceeding 15 % for the layers with the thickness less than 15 mm. This difference is decreasing with increase of the layer thickness and becomes less than 5 % for the beds thicker than 100 mm. Considering various advantages of the fluidized beds over fixed beds, including lower resistance to the gas flow, excellent gas distribution and minimal possibility of clogging in case of existence of alien particles in the gas, they are recommended for use with the minimal thickness of the layer to be larger than 100 mm.
Antioxidant properties of polyphenol‐containing extract from soybean fermented with Saccharomyces cerevisiae
Authors: Romero Ana M. , Doval Mirtha M. , Sturla Mario A. , Judis Maria A. 
Published: July 2004

AbstractThe antioxidant properties and total phenolic compounds of soybean extract fermented with Saccharomyces cerevisiae during 24 h were evaluated. Total polyphenolic compounds extracted in ethanol/water (1:1) solution were 789.54 mg/g dry extract, and flavonoids were 169.47 mg quercetin equivalents/g of dry extract. Reducing power (91.18%) and DPPH scavenging (79.30% at 4‐times diluted) were excellent, and so high as BHA, 92.17% and 73.8% respectively, while superoxide anion scavenging showed poor inhibition (4876 equivalent SOD U/g). Antioxidant activity in linoleic acid/water emulsion system of fermented extract measured as peroxide formation inhibition at 37 °C was the strongest (95.62%), while it exerted a moderate inhibition for conjugated dienes and thiobarbituric acid reactive substances (64.77% and 54.33%). At 80 °C the antioxidant activity assayed at a higher concentration was less effective (29.35% on CD; 74.58% on PV and 35.04% on TBARS).
Fourth‐order accurate compact‐difference discretization method for Helmholtz and incompressible Navier–Stokes equations
Authors: Steijl R. , Hoeijmakers H. W. M. 
Published: July 2004

AbstractA fourth‐order accurate solution method for the three‐dimensional Helmholtz equations is described that is based on a compact finite‐difference stencil for the Laplace operator. Similar discretization methods for the Poisson equation have been presented by various researchers for Dirichlet boundary conditions. Here, the complicated issue of imposing Neumann boundary conditions is described in detail. The method is then applied to model Helmholtz problems to verify the accuracy of the discretization method. The implementation of the solution method is also described. The Helmholtz solver is used as the basis for a fourth‐order accurate solver for the incompressible Navier–Stokes equations. Numerical results obtained with this Navier–Stokes solver for the temporal evolution of a three‐dimensional instability in a counter‐rotating vortex pair are discussed. The time‐accurate Navier–Stokes simulations show the resolving properties of the developed discretization method and the correct prediction of the initial growth rate of the three‐dimensional instability in the vortex pair. Copyright © 2004 John Wiley & Sons, Ltd.
Glial modulation of synaptic transmission in culture
Authors: Araque Alfonso , Perea Gertrudis 
Published: July 2004

AbstractAccumulating evidence has demonstrated the existence of bidirectional communication between glial cells and neurons, indicating an important active role of glia in the physiology of the nervous system. Neurotransmitters released by presynaptic terminals during synaptic activity increase intracellular Ca2+ concentration in adjacent glial cells. In turn, activated glia may release different transmitters that can feed back to neuronal synaptic elements, regulating the postsynaptic neuronal excitability and modulating neurotransmitter release from presynaptic terminals. As a consequence of this evidence, a new concept of the synaptic physiology, the tripartite synapse, has been proposed, in which glial cells play an active role as dynamic regulatory elements in neurotransmission. In the present article we review evidence showing the ability of astrocytes to modulate synaptic transmission directly, with the focus on studies performed on cell culture preparations, which have been proved extremely useful in the characterization of molecular and cellular processes involved in astrocyte‐mediated neuromodulation. © 2004 Wiley‐Liss, Inc.
Glial modulation of synaptic transmission: Insights from the supraoptic nucleus of the hypothalamus
Authors: Oliet Stéphane H.R. , Piet Richard , Poulain Dominique A. , Theodosis Dionysia T. 
Published: July 2004

AbstractAstrocytes clear synaptically released glutamate from the extracellular space through high‐affinity transporters present on their plasma membrane. By controlling the extracellular level of the main excitatory transmitter in the central nervous system, astrocytes thus contribute prominently to the regulation of overall cellular excitability and synaptic information processing. We recently investigated the influence of the glial environment on glutamatergic and GABAergic neurotransmission in the supraoptic nucleus of the rat hypothalamus under physiological conditions such as lactation that significantly reduce astrocytic coverage of its neurons. By performing electrophysiological analyses on this unique model of dynamic neuronal‐glial interactions, we have been able to show that the fine astrocytic processes normally enwrapping synapses serve two important functions. First, they govern the level of activation of presynaptic metabotropic glutamate receptors on glutamatergic terminals, thereby regulating synaptic efficacy at excitatory synapses. Second, they act as a physical and functional barrier to diffusion in the extracellular space, limiting spillover of glutamate and other neuroactive substances and therefore contributing to the regulation of heterosynaptic transmission and intercellular communication. © 2004 Wiley‐Liss, Inc.
Glial modulation of synaptic transmission in the hippocampus
Authors: Volterra Andrea , Steinhäuser Christian 
Published: July 2004

AbstractFor many years, astrocytes and oligodendrocytes were considered the inert partners of neurons in the central nervous system (CNS), but several recent studies have dramatically challenged this view. Glial cells express a large number of different voltage‐ and ligand‐gated ion channels (Verkhratsky and Steinhäuser. Brain Res Rev 32:380–412, 2000) as well as G‐protein‐coupled receptors (Verkhratsky et al. Physiol Rev 78:99–141, 1998)—machinery necessary to sense and respond to neuronal activity. These findings raised the fundamental question as to whether glial receptors are stimulated under physiological conditions, and what sorts of events are triggered by such activation. During the early 1990s, P. Haydon and colleagues made the seminal observation that [Ca2+]i rises in cultured astrocytes are associated with the release of glutamate, which suggested that astrocytes respond to activation and play active modulatory roles in intercellular communication (Parpura et al. Nature 369:744–747, 1994). Subsequent studies performed in situ confirmed and extended this initial observation. In this review, we will focus specifically on the hippocampus and sum up evidence of bidirectional communication between astrocytes and neurons emerging from recent studies using acute slice preparations. © 2004 Wiley‐Liss, Inc.
Role for glia in synaptogenesis
Authors: Ullian Erik M. , Christopherson Karen S. , Barres Ben A. 
Published: July 2004

AbstractNearly one‐half of the cells in a human brain are astrocytes, but the function of these little cells remains a great mystery. Astrocytes form an intimate association with synapses throughout the adult CNS, where they help regulate ion and neurotransmitter concentrations. Recent in vitro studies, however, have found that astrocytes also exert powerful control over the number of CNS synapses that form, are essential for postsynaptic function, and are required for synaptic stability and maintenance. Moreover, recent studies increasingly implicate astrocytes in vivo as participants in activity‐dependent structural and functional synaptic changes throughout the nervous system. Taken together, these data force us to rethink the role of glia. We propose that astrocytes should not be viewed primarily as support cells, but rather as cells that actively control the structural and functional plasticity of synapses in developing and adult organisms. © 2004 Wiley‐Liss, Inc.
The prevalence of depressive symptoms among elderly Chinese private nursing home residents in Hong Kong
Authors: Lun Chow Eddie Siu , Hei Kong Bernard Ming , Po Wong Mike Tak , Draper Brian , Lin Ka Leung , Sabrina Ho Shuk Kuen , Por Wong Chun 
Published: July 2004

AbstractBackgroundPrivately‐owned Nursing homes (PNH) in Hong Kong present a unique setting of institutional care where elderly with the whole spectrum of health status live together.ObjectivesThis cross‐sectional descriptive study aimed to determine the prevalence of significant depressive symptoms in a group of Cantonese‐speaking Chinese private nursing home elderly living in Hong Kong, and to identify associated psychosocial and health factors.Methodological ResultsTwo hundred and forty five residents fulfilled the inclusion criteria. Using the Chinese version of the Geriatric Depression Scale—Short Form (GDS‐SF), we detected significant depressive symptoms in 29% of subjects. Univariate analysis revealed some associated socio‐economic risk factors including current non‐Comprehensive Social Security Assistance (CSSA) recipients, education levels and low abilities for social activities. Low vision, swallowing difficulties and low levels of basic activities of daily living (BADL) as reflected by the total Modified Barthel Index of less than 61 were important health predictors. Depression was also associated with features of self‐perception of financial inadequacy, life dissatisfaction, poor self‐perceived health, poor attitudes towards living arrangement and suicidal thoughts. Stepwise logistic regression identified swallowing problems, current non‐CSSA recipient and low BADL ability as independent risk factors.ConclusionThe high prevalence of depressive symptoms in the nursing home elderly requires the attention of Government authorities, health care and social service providers. Copyright © 2004 John Wiley & Sons, Ltd.
Targeting human Ep‐CAM in transgenic mice by anti‐idiotype and antigen based vaccines
Authors: Mosolits Szilvia , Campbell Fiona , Litvinov Sergey V. , Fagerberg Jan , Crowe J. Scott , Mellstedt Håkan , Ellis Jonathan H. 
Published: July 2004

AbstractAnti‐idiotypic antibodies (anti‐Id) as surrogate TAAs have been shown to induce immunity against tumours in animals and humans. SM262 is a human monoclonal anti‐Id raised against MAb 17‐1A recognising Ep‐CAM. Plasmids encoding the variable regions of SM262 with either murine or human Fc regions, both with and without fusion to GM‐CSF were constructed. DNA was delivered by gene gun to C57BL/6 (wt) mice and mice expressing the transgene for human Ep‐CAM (tg). The immunogenicity of anti‐Id DNA constructs, anti‐Id protein and Ep‐CAM DNA vaccines was compared. SM262 plasmids induced antibodies (Abs) inhibiting MAb 17‐1A binding to SM262 as well as recognising Ep‐CAM in wt and tg mice. Fusion to GM‐CSF evoked significantly higher Ab titres, whereas a xenogeneic Fc region had no significant effect. The highest Ab titres were elicited by protein immunisation. The original Ag was superior as compared to the anti‐Id vaccines in wt but not tg mice in terms of Ab induction. A weak Ep‐CAM‐specific cytotoxic response was induced in wt but not tg mice. The data suggest that B cell tolerance to Ep‐CAM can be circumvented by anti‐Id DNA, anti‐Id protein as well as Ep‐CAM DNA immunisation. Fusion of GM‐CSF to anti‐Id increased the magnitude of the immune response with no requirement of a foreign Fc domain. Furthermore, no superiority of Ep‐CAM as compared to anti‐Id DNA vaccine was noted in tg mice and protein immunisation induced a more potent humoral response than DNA. The results might have implications for the design of future vaccine trials using Ep‐CAM as a target structure. © 2004 Wiley‐Liss, Inc.
Life stages and reproductive components of the Marmorkrebs (marbled crayfish), the first parthenogenetic decapod crustacean
Authors: Vogt Günter , Tolley Laura , Scholtz Gerhard 
Published: July 2004

AbstractRecently, we briefly reported on the first case of parthenogenesis in the decapod Crustacea which was found in the Marmorkrebs or marbled crayfish, a cambarid species of unknown geographic origin and species identity. Curiously, this animal is known only from aquarium populations, where it explosively propagates. By means of light and electron microscopic techniques we have now investigated the reproductive components of this crayfish, using more than 100 specimens ranging from hatchling to repeatedly spawned adult. Additionally, we documented its principal life stages. Our results revealed that the external sexual characters and also the gonads of the marbled crayfish are purely female, making this fast‐reproducing species a good model for investigating female reproductive features in crayfish. Testicular tissues, ovotestes, or male gonoducts, gonopores, or gonopods were never found, either in small juveniles or large adult specimens, confirming the parthenogenetic nature of this crayfish. Parthenogenesis may have arisen spontaneously or by interspecific hybridization since Wolbachia‐like feminizing microorganisms were not found in the ovaries. The external sexual characters of the marbled crayfish are first recognized in Stage 4 juveniles and are structurally complete ∼2 months after hatching in specimens of ∼2 cm total length. In the same life stage the ovary is fully differentiated as well, although the oocytes are in previtellogenic and primary vitellogenic stages only. The architecture of the mature ovary and also the synchronous maturation of cohorts of primary vitellogenic oocytes by secondary vitellogenesis are in general agreement with data published on ovaries of bisexual crayfish. New results were obtained with respect to the muscular nature of the ovarian envelope and its extensive proliferation after the first spawning, the distribution of hemal sinuses in the ovarian envelope and in the interstitium around the oogenetic pouches, the high transport activity of the follicle cells, and the colonization of oogenetic pouches by previtellogenic oocytes that originate in the germaria. Investigation of the nuclei of oocytes in the germaria and oogenetic pouches revealed no signs of meiosis, as usually found in females of bisexual decapods, suggesting that parthenogenesis in the marbled crayfish might be an apomictic thelytoky. The detection of new rickettsial and coccidian infections in the ovary and further organs raises fears that the marbled crayfish might endanger native European species by transmission of pathogens once escaped into the wild. J. Morphol. 261:286–311, 2004. © 2004 Wiley‐Liss, Inc.
Excurrent duct system of the male turtle Chrysemys picta
Authors: Holmes Hilary J. , Gist Daniel H. 
Published: July 2004

AbstractThe epididymis and efferent duct system of the turtle Chrysemys picta were examined. Seminiferous tubules are drained by a series of ducts that form a rete exterior to the tunica albuginea. The rete is located lateral to the testis and consists of anastamosing tubules of varying diameters, lined by a simple epithelium consisting of squamous to cuboidal cells. The rete is highly vascularized. A series of tubules (efferent ductules) connect the rete to the epididymis proper. The efferent ductules are highly convoluted, running between the epididymal tubules and are of varying diameters. The simple columnar epithelium lining these tubules possesses tight junctions, with every third or fourth cell possessing long cilia that protrude into the lumen. The cytoplasm of these epithelial cells contains abundant mitochondria. In the central portion of the efferent ductule, epithelial cells possess granules that appear to be secreted into the lumen by an apocrine process. The epididymis proper is a single, long, highly convoluted tubule that receives efferent ductules along its entire length. It is lined by a pseudostratified epithelium containing several cell types. The most abundant cell (vesicular cell) lacks cilia, but has a darkly staining apical border due to numerous small vesicles immediately beneath the luminal membrane. The small vesicles appear to fuse with each other basally to form larger vesicles. These cells appear to have an absorptive function, and occasionally sperm are embedded in their cytoplasm. The second‐most abundant cell is a basal cell found along the basement membrane. The number of these cells fluctuates throughout the year, being most abundant in late summer and early fall. A small narrow cell with an oval nucleus and darkly staining cytoplasm, extending from the basement membrane to the apical surface, is present in small numbers, particularly in the caudal regions of the epididymis. This cell is frequently found in association with another narrow cell having a rounded nucleus and abundant mitochondria in its cytoplasm. J. Morphol. 261:312–322, 2004. © 2004 Wiley‐Liss, Inc.