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  • Digitale Medien  (6)
  • 2005-2009
  • 2000-2004  (6)
  • 2001  (6)
Materialart
  • Digitale Medien  (6)
Erscheinungszeitraum
  • 2005-2009
  • 2000-2004  (6)
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 3157-3162 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: In this paper the temperature/pressure dependence of the refractive index of liquid water is analyzed using the two-state outer-neighbor mixed bonding structural model. So far, this theoretical model has been successful in reproducing, usually within the experimental uncertainty, the temperature/pressure dependence of the density, the viscosity, and the oxygen–oxygen pair correlation functions, in addition to the isothermal compressibility and isotope effects of this important substance. The philosophy of the present paper is to use the high accuracy of refractive index measurements to further test this model. It is shown that a very simple linear dependence with respect to temperature and pressure of the specific refractions LI and LII of the two contributing structural components in this two-state model is sufficient to give better than 5-decimal-point agreement with the experimental refractive index data at low pressures and temperatures between about −10 °C and +70 °C. The maximum in the refractive index between −5 °C and +5 °C is reproduced to an even better precision. Generally better than 4-decimal-point accuracy is achieved for higher pressures, where the experimental data are less accurately known. The pressure dependence considered here also allows the calculation of the isothermal piezo-optic coefficient as a function of temperature, which exhibits a minimum near 50 °C. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 115 (2001), S. 7796-7797 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: The valid range of the emphasized experimental data and need, in very precise comparisons, to compensate for the very small temperature shifts resulting from revisions in the accepted standard for the International Temperature Scale over the years, are acknowledged. However, it is emphasized that these corrections do not invalidate the approach and that the physical motivation underlying the mixture model analysis leads to physically meaningful fitting parameters; a result not found in any previous treatment. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 15 (2001), S. 0 
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Previous studies have shown that intragastric administration of unfractionated heparin enhances gastric ulcer healing in rats. As the large molecule of heparin may be partially degraded in the upper gastrointestinal tract, it is likely that fragments of heparin, derived from the unfractionated parent compound, are involved in the anti-ulcer action in the stomach. Therefore, it is possible that low molecular weight heparin may have a similar ulcer healing effect.〈section xml:id="abs1-2"〉〈title type="main"〉Methods:Male Sprague–Dawley rats with acetic acid-induced gastric ulcers were given a 3.0-kDa low molecular weight heparin (0.6–6.0 mg/kg) intravenously or intragastrically once daily for 4 days. Ulcer healing, mucosal histological changes, angiogenesis and gastric mucus production both in vivo and in vitro were determined. The bleeding time was measured to indicate the anticoagulation activity.〈section xml:id="abs1-3"〉〈title type="main"〉Results:Both intravenous and intragastric low molecular weight heparin dose dependently accelerated gastric ulcer healing, which was accompanied by a significant increase in mucosal regeneration and proliferation, angiogenesis and mucus content in the stomach. The drug also stimulated the mucus production in MKN-28 cells. Drug administration by either route did not alter the bleeding time in rats.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions:A 3.0-kDa low molecular weight heparin possesses an ulcer healing effect similar to that of unfractionated heparin in the stomach of the rat. This smaller molecular drug is superior to the unfractionated form, does not affect the coagulation activity and may show better absorption in the gastrointestinal tract.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science, Ltd
    Aquaculture research 32 (2001), S. 0 
    ISSN: 1365-2109
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Significant efforts should be devoted to reducing waste outputs from aquaculture operations in order to lower the environmental impacts of aquaculture in many parts of the world. Since most aquaculture wastes are ultimately from dietary origin, reduction of waste outputs should first be through improvements of diet formulation and feeding strategies. The first step in the production of feeds producing less solid waste is to eliminate poorly digestible ingredients (such as whole grain or grain by-products used as binders and fillers in the feed formulae) and to use highly digestible ingredients with good binding properties. Further reduction of solid waste can then be achieved through careful selection of the ingredients to improve apparent digestibility and the nutrient balance of the feed. Nitrogen waste outputs can be reduced through the reduction of the digestible protein to digestible energy (DP/DE) ratio of the diet. Phosphorus waste outputs can be reduced through careful selection of the ingredients and optimization of the digestible phosphorus content of the diet to meet the requirement of the fish but avoid greatly exceeding this required level. Finally, feeding practices that minimize feed wastage should be adopted since feed wastage can have a very significant impact on waste outputs from fish culture operations.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Helicobacteria pylori infection of gastroduodenal mucosa is strongly associated with gastritis and peptic ulcer disease. The aims of the present study were to compare the gastroduodenal mucosal levels of epidermal growth factor (EGF) and its receptor (EGFR) among H. pylori-negative controls and H. pylori infected patients with chronic active gastritis or gastroduodenal ulcer before and after H. pylori eradication.〈section xml:id="abs1-2"〉〈title type="main"〉Methods:The protein levels of EGF in mucosal tissues and saliva were determined by a solid-phase enzyme-linked immunosorbent assay (ELISA). Repeat transcription-polymerase chain reaction and the following polymerase chain reaction ELISA were employed to examine the mucosal EGFR mRNA expression.〈section xml:id="abs1-3"〉〈title type="main"〉Results:Mucosal injury and H. pylori infection increased EGF protein levels and EGFR mRNA expression in the antral mucosa. The concentration of EGF in saliva was not affected by mucosal damage or H. pylori infection. Successful H. pylori eradication normalized the EGFR mRNA back to its basal level 6 weeks after treatment. However, after unsuccessful eradication their high levels in the antrum persisted. All patients experienced ulcer healing after drug treatment, regardless of H. pylori eradication.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions:Mucosal damage increased the expression of EGF protein and EGFR mRNA in the gastric mucosa. H. pylori could induce the expression of EGFR but not the EGF in the antral mucosa. The expression of EGFR could be a contributing factor for ulcer healing in patients with H. pylori infection.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Diversity in metronidazole susceptibility and genotypes of Helicobacter pylori have been reported with varying results in different areas.〈section xml:id="abs1-2"〉〈title type="main"〉Aims:To investigate the prevalence of multiple strain infection in a symptomatic Chinese population and to determine the metronidazole susceptibility pattern and genotypic characteristics of these infecting strains.〈section xml:id="abs1-3"〉〈title type="main"〉Methods:Gastric biopsies from antrum, body and cardia were taken during upper endoscopy in symptomatic patients referred to our department. Pooled cultures and single colony isolates were obtained and tested for metronidazole susceptibility and random amplified polymorphic DNA (RAPD) fingerprint patterns.〈section xml:id="abs1-4"〉〈title type="main"〉Results:A total of 461 isolates were successfully cultured from 46 patients. Fifty-seven per cent of subjects had metronidazole-resistant strains. Among them, 77% carried a mixture of sensitive and resistant strains, non-uniformly distributed in the gastric mucosa. Mixed genotypes were found by RAPD typing in 24% of subjects. These did not correlate with the metronidazole susceptibility/resistance pattern.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusion: H. pylori infections with mixed metronidazole sensitive/resistant strains and mixed genotypes are common in Hong Kong. This makes it prudent to use bacterial strains from several biopsy sites when testing for traits such as drug resistance or virulence in relation to disease.
    Materialart: Digitale Medien
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