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  • 1
    ISSN: 1432-1238
    Keywords: Key words Cardiopulmonary bypass ; Gastrointestinal permeability ; Dopexamine ; Dopamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective: To compare the effects of dopexamine and dopamine on the mucosal permeability of the gastrointestinal tract (GIT). Design: Prospective, randomised clinical trial. Setting: Intensive care unit of a postgraduate teaching hospital, London, England. Patients: Thirty patients undergoing elective surgery involving cardiopulmonary bypass, performed by a single surgeon. Interventions: Patients were randomly assigned to receive either dopexamine 2.0 μg/kg per min or dopamine 2.5 μg/kg per min for the duration of the study period. Measurements and main results: Hemodynamic parameters and gastric intramucosal pH (pHi) were measured at intervals throughout the study. GIT permeability was measured once, post-operatively, using the ratio of absorbed lactulose to L-rhamnose. The groups were similar with respect to demographics, pre- and post-operative risk factors. The lactulose/rhamnose ratio was (mean ± SEM) 0.44 ± 0.10 in the dopexamine group vs 0.65 ± 0.08 in that receiving dopamine (p 〈 0.05). The dopexamine group had a significantly higher oxygen delivery preoperatively (479.5 ± 32.0 ml/min per m2 vs 344.4 ± 23.9 ml/min per m2 for dopamine, p 〈 0.01), but no other significant differences emerged between the groups. Conclusions: Compared to dopamine, dopexamine reduces GIT permeability following surgery involving cardiopulmonary bypass. The mechanism of this effect remains unclear.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Bradford : Emerald
    Employee relations 18 (1996), S. 9-19 
    ISSN: 0142-5455
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Economics
    Notes: Describes the utility of supply chain partnerships as a mechanism for the diffusion of change in employee relations. Uses case study and survey evidence to explain the means by which this can be achieved. Examines data relating to both customer and supplier organizations in the manufacturing sector. Concludes that the customer-supplier relationship can act as an agent of change in human resource management, particularly as they do not need to be artificially created, and can reach "peripheral" as well as "core" firms. Suggests that the local economic development agencies may be able to encourage the formation of networks of organizations in a particular industry and promote the spread of innovations in employee relations in this way.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1617-4623
    Keywords: Key words Cleavage and polyadenylation specificity factor ; Cleavage stimulation factor ; Drosophila melanogaster ; mRNA processing ; Additional sex combs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Processing of the 3′ end of mRNA precursors depends on several proteins. The multisubunit cleavage and polyadenylation specificity factor (CPSF) is required for cleavage of the mRNA precursor as well as polyadenylation. CPSF interacts with the cleavage stimulatory factor complex (CstF), and this interaction increases the specificity of binding. Following cleavage downstream of the AAUAAA site, CPSF and poly(A) polymerase (PAP) are required for efficient polyadenylation. Recently, it has been shown that 160-kDa subunit of CPSF interacts directly with the 77-kDa subunit of CstF, which is homologous to the product encoded by the Drosophila gene su(f), and with PAP. Here we report the cloning and characterization of a Drosophila homologue of CPSF-160. The 1329-amino acid dCPSF protein exhibits about 45% and 20% sequence identity, respectively, to its mammalian and yeast counterparts over its entire length. We show that the CPSF homologue is expressed throughout development and that CPSF is essential for viability. Mutations in the cpsf gene did not alter the phenotype of homozygous su(f) mutations, suggesting that, for most genes, processing of 3′ termini is not sensitive to small changes in cpsf and su(f) dosage.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1617-4623
    Keywords: Key words Polycomb group ; Trithorax group ; Homeotic mutations ; Drosophila melanogaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The protein products of Polycomb group (PcG) and trithorax group (trxG) genes are required for the maintenance of the transcriptionally repressed and active states, respectively, of the homeotic genes. Mutations in PcG genes produce gain-of-function (posterior) homeotic transformations, while mutations in trxG genes produce loss-of-function (anterior) homeotic transformations. Double mutant combinations between a PcG gene and a trxG gene suppress the homeotic transformations seen with either mutation alone, suggesting that PcG and trxG genes act antagonistically. The PcG gene Additional sex combs (Asx) is interesting because one mutant allele, Asx P1 , causes both anterior and posterior homeotic transformations. Asx P1 and other Asx mutations were crossed to mutations in the PcG gene Polycomb (Pc) and the trxG gene trithorax (trx). Asx alleles enhance both PcG and trxG homeotic transformations, showing that Asx is required for both the activation and the repression of homeotic loci. Asx also shows strong allele-specific interactions with the PcG genes Pc and super sex combs (sxc). Together, these data indicate that there are functional interactions between Asx, Pc and sxc in vivo. ASX may interact with a PcG complex containing PC and SXC and mediate activation versus repression at target loci, perhaps by interacting directly with the TRX protein.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 56 (1999), S. 807-816 
    ISSN: 1420-9071
    Keywords: Key words. Yeast; aging; senescence; helicase; silencing; nucleolus; metabolism; retrograde signaling.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The molecular mechanisms of aging are most fully understood for the budding yeast Saccharomyces cerevisiae. Recent advances in our understanding of aging in this organism have enabled researchers to answer some fundamental questions about the aging process. Is aging due to a multitude of ‘mechanisms’ or can there be a key few? Can we design single-gene mutations that will prolong life? Can we prolong life whilst maintaining health and fecundity? The various contributing factors to yeast longevity, uncovered thus far, fall into three classes: DNA metabolism, heterochromatin, and metabolic activity. However, these separate classes may actually represent different aspects of the same aging mechanism based on genome stability. This review examines the recent advances in our understanding of yeast aging and discusses their relevance, if any, to the human condition.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    International journal of computer vision 18 (1996), S. 77-91 
    ISSN: 1573-1405
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper presents a means of segmenting planar regions from two views of a scene using point correspondences. The initial selection of groups of coplanar points is performed on the basis of conservation of two five point projective invariants (groups for which this invariant is conserved are assumed to be coplanar). The five point correspondences are used to estimate a projectivity which is used to predict the change in position of other points assuming they lie on the same plane as the original four. The variance in any points new position is then used to define a distance threshold between actual and predicted position which is used as a coplanarity test to find extended planar regions. If two distinct planar regions can be found then a novel motion direction estimator suggests itself. The projection of the line of intersection of two planes in an image may also be recovered. An analytical error model is derived which relates image uncertainty in a corner's position to genuine perpendicular height of a point above a given plane in the world. The model may be used for example to predict the performance of given stereo ground plane prediction system or a monocular drivable region detection system on and AGV. The model may also be used in reverse to determine the camera resolution required if a vehicle in motion is to resolve obstacles of a given height a given distance from it.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 17 (1997), S. 203-205 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract T c data are reported for powders of cation-stoichiometric Bi2Sr2CaCu2Oδ and for nonstoichiometric samples based on the three mechanisms Bi⇄Sr, Sr⇄Ca and Sr vacancy. For each, the T c values depend critically on the final oxygen contents, which were varied by heating samples in either O2 or N2 at different temperatures. Stoichiometric Bi2Sr2CaCu2Oδ has the highest T c, 92 K, obtained after heating in O2 at ∼ 820 °C. Heating in O2 at lower temperatures gives rise to overdoping and T c decreases to 60 K. The other cation compositions show a smaller maximum T c but also less reduction in T c on overdoping. Under-doped samples, with reduced T c values were obtained on heating in N2. These data, together with selected literature results, lead to a unified picture of the variation of T c with cation composition and oxygen content.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Spark-plasma-sintering (SPS) has been applied to BaTiO3 to prepare dense ceramics consisting of submicrometre-sized powder. Relatively dense (typically 97% of the theoretical X-ray density) pellets with an average grain size remaining similar to that of the starting powder, approximately 0.6 μm, were obtained by the SPS process. Fixed frequency (1 kHz) measurements show the room temperature permittivity of SPS ceramics to be relatively high, approximately 3500, and at least double the value of conventionally sintered ceramics, approximately 1500. Alternating current (a.c.) impedance spectroscopy measurements show that SPS is an effective process to reduce the influence of intergranular (grain boundary) effects on the permittivity and direct current (d.c.) resistance characteristics of BaTiO3 ceramics substantially.
    Type of Medium: Electronic Resource
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