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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 6298-6303 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Current filaments formed in the parameter regime of the low-temperature impurity impact ionization breakdown of p-germanium were investigated by measuring tunneling and point contact characteristics of a scanning tunneling microscope tip fixed at certain sample positions under variation of the sample voltage. The results clearly indicate that the tip current is determined by local potential variations which can be interpreted by a model for the filament taking into account the finite electric resistivity of the sample contacts. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 8 (2001), S. 3502-3505 
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The numerical large eddy simulation (LES) technique is tested on decaying magnetohydrodynamic (MHD) turbulence. The LES approach allows for a strong reduction in computational cost compared to direct numerical simulations by modeling the effects of the smallest turbulent scales instead of computing them directly. Two small-scale models of eddy-viscosity type are presented for this purpose in combination with a procedure for the self-consistent calculation of the model parameters in the course of the simulation. The method is successfully tested by comparing the obtained results to a high-resolution direct numerical simulation of decaying three-dimensional MHD turbulence. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 1150-1152 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present a procedure that locally determines the composition (from a given set of available materials) of a segmented or graded thermoelectric generator leg in order to maximize its output power to a matched load. The method is based on a new interpretation of the electrical output relation, which is organized to resemble a differential output power along the device coordinate. The procedure is applied to calculate the segment length and output power of a segmented bismuth-telluride/iron-disilicide based thermoelectric generator leg. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 1421-1423 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An integrated dc superconducting quantum interference device (SQUID) magnetometer has been fabricated using a YBa2Cu3O7−x–SrTiO3–YBa2Cu3O7−x multilayer process. The magnetometer consists of a 8.3 mm×8.6 mm pickup coil coupled inductively to a small washer-type SQUID with 9 Ω bicrystal junctions via an integrated 101/2-turn input coil. Using simple direct-coupled read-out electronics with additional positive feedback, a noise level of 9.7 fT/(square root of)Hz at 1 kHz and 53 fT/(square root of)Hz at 1 Hz was measured inside a magnetically shielded room. Due to the low noise level biomagnetic heart and brain signals with high quality and the very weak signals of the peripheral nerve system were recorded. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 15 (2001), S. 0 
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Proton pump inhibitor-based therapy including two antibiotics is the treatment of choice for Helicobacter pylori infection. Oral antibiotic treatment can lead to intestinal overgrowth of potentially pathogenic bacteria.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:To investigate the intestinal microflora before and at different times after H. pylori treatment with omeprazole, clarithromycin and metronidazole.〈section xml:id="abs1-3"〉〈title type="main"〉Methods:Bacterial growth in faecal samples from 51 patients infected with H. pylori was determined qualitatively and quantitatively. During the same period of time, stool samples from 27 H. pylori-negative controls were taken and investigated at the same intervals.〈section xml:id="abs1-4"〉〈title type="main"〉Results:The microflora of H. pylori-infected patients was different from that in H. pylori negative controls. It was characterized by a high concentration of lactobacilli, mainly Lactobacillus acidophilus. Immediately after therapy there was an increased colonization with yeasts, while the growth of lactobacilli and other species was inhibited. Clostridium difficile was cultured from three cases, but without clinical manifestations of pseudomembranous colitis. After 4 weeks of therapy, the microflora returned to normal and was not different from that of the H. pylori-negative control group.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusions:In H. pylori-positive patients the intestinal flora is characterized by an increase in growth of acid-tolerant L. acidophilus. Eradication therapy exerts only a short-term influence on intestinal flora, whereas in the long term, the intestinal microflora is restored to a pattern similar to that of the control group.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1360-0443
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: Aims  The non-benzodiazepine hypnotics zolpidem and zopiclone, which are indicated for short-term treatment of insomnia, were considered originally by physicians as almost devoid of abuse and dependence potential. Several recent publications, however, have suggested that both agents carry a significant risk of abuse. To substantiate and re-evaluate this situation, the world literature was reviewed for cases of dependence of both agents; these cases were analysed in order to identify certain underlying patterns, if evident.Methods  A systematic review based on a Medline literature search was conducted including the years 1966–2002 to assemble all available clinical case reports that were analysed for typical features of abuse and dependence according to prespecified criteria. Only case reports were of interest, and clinical studies were excluded. No limitations as to language or publication year were applied. The terms ‘zolpidem’, ‘zopiclone’ and ‘abuse’, ‘dependence’, ‘addiction’, ‘withdrawal’ and ‘intoxication’ were used to identify relevant publications. Potentially relevant citations were retrieved and assessed for inclusion independently by two authors.Results  A total of 36 cases for zolpidem were identified, most of them reported in recent years, and 22 cases for zopiclone. Both sexes were involved to a similar extent; and cases were reported in all age groups. In extreme cases, dose increases reached a factor of 30–120 above the recommended doses. The majority of patients had a history of former drug or alcohol abuse and/or other psychiatric conditions.Conclusion  On the basis of world-wide prescription numbers, which are approximately twofold higher for zolpidem (1 338 774 000 tablets from June 2001 to June 2002 in Europe, Japan and United States) than for zopiclone (664 897 000 tablets during the same period in Europe and Japan), the relative incidence of reported dependence similar for both drugs and remarkably lower than that of benzodiazepines used for the treatment of disturbed sleep. The findings offer the conclusion that zolpidem and zopiclone are relatively safe drugs. However, as both drugs are psychotropic drugs, patients with a history of abuse or dependence and those with psychiatric diseases seem to be at increased risk of abuse of these agents.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 146 (1997), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: All strains of Salmonella enterica investigated were found to carry the Salmonella enterotoxin gene (stn) as determined by PCR and hybridization studies. However, when using CHO-K1 cells for testing the toxicity of the strains, not all strains showed a toxic effect (cell elongation) on the cells or did so only at a low level. The cultivation of Salmonella in contact with epithelial cells (IEC-6) led to an increase in the production of toxin. The stn gene expression was detectable with the help of the RT-PCR after 3 h of incubation. The RNA of the strains was isolated, transcribed into cDNA (with MMLV-reverse transcriptase) and amplified using PCR. The PCR products were separated electrophoretically using a polyacrylamide gel and detected by silver staining.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: In Candida albicans wild-type cells, the β1,6-glucanase-extractable glycosylphosphatidylinositol (GPI)-dependent cell wall proteins (CWPs) account for about 88% of all covalently linked CWPs. Approximately 90% of these GPI-CWPs, including Als1p and Als3p, are attached via β1,6-glucan to β1,3-glucan. The remaining GPI-CWPs are linked through β1,6-glucan to chitin. The β1,6-glucanase-resistant protein fraction is small and consists of Pir-related CWPs, which are attached to β1,3-glucan through an alkali-labile linkage. Immunogold labelling and Western analysis, using an antiserum directed against Saccharomyces cerevisiae Pir2p/Hsp150, point to the localization of at least two differentially expressed Pir2 homologues in the cell wall of C. albicans. In mnn9Δ and pmt1Δ mutant strains, which are defective in N- and O-glycosylation of proteins respectively, we observed enhanced chitin levels together with an increased coupling of GPI-CWPs through β1,6-glucan to chitin. In these cells, the level of Pir-CWPs was slightly upregulated. A slightly increased incorporation of Pir proteins was also observed in a β1,6-glucan-deficient hemizygous kre6Δ mutant. Taken together, these observations show that C. albicans follows the same basic rules as S. cerevisiae in constructing a cell wall and indicate that a cell wall salvage mechanism is activated when Candida cells are confronted with cell wall weakening.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Different patterns of β-catenin expression in gastric carcinomas: relationship with clinicopathological parameters and prognostic outcome Aims: The cadherin–catenin complex is known to play a critical role in maintenance of cell adhesion. Additionally β-catenin (β-ct) can also take part in signal transduction and nuclear β-ct expression could be correlated with poor prognosis in several malignancies. Since, in gastric cancer, this role of β-ct is still uncertain, we investigated the expression pattern of β-ct as well as the possible prognostic role. Methods and results: β-catenin expression was immunohistochemically investigated in a retrospective series of 401 R0-resected gastric carcinomas. Out of these cases, 54 tumours (13.5%) revealed a preserved membranous β-ct expression similar to that in normal gastric mucosa. In 80 tumours β-ct expression was moderately reduced and in 117 tumours highly reduced. In 150 tumours (37.4%), no or only a weak membranous β-ct expression was found. Additionally, in 53 tumours, a strong β-ct expression could be observed in the cytoplasm with a simultaneous nuclear β-ct immunoreactivity in 17 of these 53 tumours, while nine tumours only showed nuclear immunoreactivity without cytoplasmic staining. There were no significant correlations between the degree of membranous β-ct expression or the different staining pattern (membranous vs. cytoplasmic/nuclear) and the grade of tumour differentiation, the histological tumour type according to Lauren, as well as with the prognostic parameters pT, pN category and vascular invasion. No associations could be found with tumour cell proliferation and the expression of E-cadherin, irrespectively of the different β-ct staining pattern. Univariate analysis revealed no influence on survival, either for membranous or for cytoplasmic/nuclear β-ct expression. Conclusion: Our data on 401 tumours suggest that activation of the Wnt/β-catenin signalling does also occur in a subset of gastric carcinomas. However, in gastric cancer, neither the presence of cytoplasmic/nuclear β-ct expression nor the reduction or loss of membranous β-ct expression is correlated with a specific histological tumour type, tumour progression or prognosis.
    Type of Medium: Electronic Resource
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