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  • 1
    Digitale Medien
    Digitale Medien
    Performance of a materials science facility at the Photon Factory: Soft x-ray beamline BL 13C coupled with multipurpose analytical apparatus : Proceedings of the 5th international conference on synchrotron radiation instrumentation (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 1780-1782 
    Details
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The performance data of an undulator soft x-ray beamline based on the cylindrical element monochromator concept are described. Photon fluxes over 1012 photon/s 0.1% b.w. are achieved with the slit width of 100 μm at the harmonic peaks of a 13-period undulator. The maximum resolution obtained at the N K edge (E/ΔE) is ≈5000 with the slit width of 10 μm. The beamline is equipped with a multipurpose analytical instrument having a hemispherical electron analyzer and other detectors. The system is used for both x-ray photoelectron spectroscopy and x-ray absorption fine structure analyses for surface and materials science. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1145848
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  • 2
    Digitale Medien
    Digitale Medien
    Effects of broad-waveguide structure in 0.8 μm high-power InGaAsP/InGaP/AlGaAs lasers (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 1839-1841 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Systematic study on the effects of the waveguide thickness Wg has been carried out for 200-μm-wide stripe separate-confinement-heterostructure lasers in the range of Wg=0.22–1.2 μm while the width of single quantum well is kept constant at 10 nm. The internal loss αi is reduced from 1.7 to 1 cm−1 when Wg is increased from 0.22 to 1.2 μm. It is shown that αi is not determined by the free-carrier absorption of clad layers, but primarily by Γ, the optical confinement factor, most probably due to scattering at the quantum well/waveguide interfaces. The external differential quantum efficiency ηd monotonically increases with Wg for pulsed operation. By contrast, ηd is maximum at Wg=0.8 μm for continuous-wave (cw) operation. Both the threshold carrier density and the threshold temperature sensitivity increases with Wg for Wg≥0.8 μm, which decreases ηd in cw operation. When 200-μm-wide devices (20%/97% coated) were life tested at 2 W and 30 °C, the median degradation rate shows a minimal value of 3×10−6 h−1 at Wg=0.8 μm, which is 7 times smaller than that at Wg=0.22 μm. The facet temperature measured by the modulation reflectance is also minimized at Wg=0.8 μm. In broad-waveguide lasers with increasing Wg, the increase in carrier overflow competes with the reduction of optical power density, and thus self-absorption in the quantum well, which determines the optimal Wg. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.124845
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  • 3
    Digitale Medien
    Digitale Medien
    Assessment and treatment of liver disease in Japanese haemophilia patients (1998)
    Oxford, UK : Blackwell Science Ltd
    Haemophilia 4 (1998), S. 0 
    Details
    ISSN: 1365-2516
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Summary. We studied the prevalence of the hepatitis C virus (HCV), human immunodeficiency virus (HIV) and GB virus C or hepatitis G virus (GBV-C/HGV), and characteristics of infections in Japanese haemophilia patients. Haemophilia patients were highly infected with HCV (88.2%) because of frequent use of unheated blood concentrates. Analysis for HCV genotypes revealed characteristics of HCV infection in haemophilia patients. Japanese haemophilia patients were highly infected with rare genotypes in Japan: genotype 1a (26.5%), genotype 3 (14.5%) and genotype 4 (2.4%). HIV infection was observed in 32.3% of haemophilia patients. HCV quasispecies (clones) and direct sequencing were investigated in patients with a single HCV genotype in the hypervariable region 1 of HCV, which resulted in a high degree of diversity. This indicates that even a single genotype of HCV might have multiple origins. GBV-C/HGV infection was noted in 20.9% of Japanese haemophilia patients. Over 40 haemophilia patients with chronic hepatitis C have been treated with interferon alpha for 6 months at total doses of 480–720 million units. About 38% showed clearance of HCV RNA from serum. Six patients with HIV infection were included in the study and they did not show eradication of HCV from the serum. This might derive from that they had high serum HCV RNA titers and genotype 1a or 1b. Histologic assessment was performed in 36 haemophilia patients with HCV. No case showed a histologically normal liver. Hepatic fibrosis in the biopsy specimens was classified into five stages of fibrosis and compared with serum hepatic fibrosis markers. Serum hyaluronic acid mostly correlated with hepatic fibrosis (γ= 0.78, P 〈 0.0001) followed by type IV collagen (γ= 0.38, P 〈 0.05). This suggests that estimation of serum fibrosis markers might be substituted for liver biopsy in haemophilia patients.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-2516.1998.440595.x
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  • 4
    Digitale Medien
    Digitale Medien
    Fatal liver failure in haemophiliacs with HIV-induced immunodeficiency: observation of six patients (1999)
    Oxford UK : Blackwell Science Ltd
    Haemophilia 5 (1999), S. 0 
    Details
    ISSN: 1365-2516
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: We observed six cases of haemophiliacs with HIV-induced immunodeficiency who died from fatal liver failure despite the absence of evident cirrhosis. They all had the infection with hepatitis viruses (two patients with hepatitis B and D viruses and four patients with hepatitis C virus) and their CD4 counts were severely decreased. They were much younger than cirrhotic haemophiliacs without HIV. Their serum levels of hyaluronic acid and type IV collagen were lower than those in haemophiliacs with cirrhosis, and were normal. No patients had experienced symptoms or concomitant diseases characteristic of cirrhosis, such as ascites, jaundice, oesophageal/gastric varices or hepatocellular carcinoma, except for one case who had a history of mild ascites. The characteristics of this liver failure were different from liver failure resulting from cirrhosis caused by chronic hepatitis, which suggests liver failure that is specific to patients with immunodeficiency. This kind of liver failure can be a factor threatening survival in patients with HIV infection and with hepatitis virus co-infection in an immunodeficient state.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-2516.1999.t01-1-00281.x
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  • 5
    Digitale Medien
    Digitale Medien
    Effects of PACAP-VIP Hybrid Peptides on Gastric Blood Flow in Conscious Dogs (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 805 (1996), S. 0 
    Details
    ISSN: 1749-6632
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Allgemeine Naturwissenschaft
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1749-6632.1996.tb17512.x
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  • 6
    Digitale Medien
    Digitale Medien
    EFFECTS OF ANTI-PARKINSONIAN DRUGS ON NEUROBEHAVIOURAL CHANGES INDUCED BY BILATERAL 6-HYDROXYDOPAMINE LESIONS IN RATS (1999)
    Melbourne, Australia : Blackwell Science Pty
    Clinical and experimental pharmacology and physiology 26 (1999), S. 0 
    Details
    ISSN: 1440-1681
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: 1. Effects of anti-Parkinsonian drugs on neurobehavioural changes induced by bilateral lesions of dopaminergic neurons were investigated in rats.2. Dopaminergic neurons in rats were lesioned bilaterally by injection of 6-hydroxydopamine (6-OHDA; 8 μg) into the medial forebrain bundle at the level of the posterolateral hypothalamus. As a result, a decrease in locomotor activity and marked catalepsy and prolongation of grasping time were observed.3. Levodopa, talipexole, bromocriptine and theophylline dose-dependently antagonized the decrease in locomotor activity induced by bilateral 6-OHDA lesions. These drugs also showed antagonistic effects on the appearance of catalepsy and prolongation of grasping time induced by bilateral 6-OHDA lesions. In contrast, trihexyphenidyl showed no antagonizing effect on the neurobehavioural changes induced by 6-OHDA lesions at any concentration tested.4. Combined treatment with levodopa and talipexole antagonized the neurobehavioural changes induced by bilateral 6-OHDA lesions, whereas no marked changes were observed when either drug was administered separately. The same findings were noted with the simultaneous use of either levodopa (2 mg/kg) and theophylline (2 mg/kg) or talipexole (0.005 mg/kg) and theophylline (2 mg/kg).5. These results indicate that this model may be useful for estimating the effects of drugs in the treatment of Parkinson's disease.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1440-1681.1999.03051.x
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  • 7
    Digitale Medien
    Digitale Medien
    Prevention of water immersion stress-induced gastric lesions through the enhancement of nitric oxide synthase activity in rats (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Alimentary pharmacology & therapeutics 10 (1996), S. 0 
    Details
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background: Gastric mucosal microcirculation is an important factor in the protection of gastric mucosa, and nitric oxide (NO) plays a crucial role in the regulation of regional blood flow. This study was designed to evaluate the effect of cetraxate, an anti-ulcer drug, on water immersion stress-induced gastric lesions in relation to the changes in NO synthase activity. Methods: Gastric lesions were induced in rats by water immersion stress. The effects of cetraxate on NO synthase activity with or without stress was determined enzymatically. Changes in gastric mucosal prostaglandin (PG) contents with or without stress were also determined using high-performance liquid chromatography. Gastric mucosal blood flow was measured by hydrogen gas clearance technique. Results: Water immersion stress-induced gastric lesions. Cetraxate significantly mitigated the lesions but NG-monomethyl-l-arginine (l-NMMA), a specific inhibitor of NO synthase, exacerbated the lesions. The favourable effect of cetraxate was remarkably diminished by administration of l-NMMA. NO synthase activity decreased significantly by 6 h after stress. Cetraxate treatment increased NO synthase activity throughout the experiment in rats with or without stress treatment. Water immersion stress decreased all PGs detected, i.e. 6-keto-PGF1α, PGF2α PGE2 and PGD2. Cetraxate prevented stress-induced decreases in PG contents. l-NMMA showed no significant effect on PG contents. Cetraxate increased gastric mucosal blood flow significantly and l-NMMA cancelled out cetraxate-induced increase in blood flow. Conclusions: The pharmacological efficacy of anti-ulcer drugs such as cetraxate might be attributable to the enhancement of NO synthase activity resulting in an increase in gastric mucosal blood flow.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-2036.1996.tb00182.x
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  • 8
    Digitale Medien
    Digitale Medien
    Effects of FK506 on an experimental model of colitis in rats (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Alimentary pharmacology & therapeutics 9 (1995), S. 0 
    Details
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Aim: To assess the effects of FK506, a newly developed immunosuppressant, on experimental colitis in rats. Methods: Experimental colitis was induced by a single colonic instillation of hapten 2,4,6-trinitrobenzene sulphonic acid (TNB) in anaesthetized rats. Rats received 30 mg TNB dissolved in 0.25 mL of 50% ethanol, and were sacrificed on day 5 following 4 days dosing with FK506 (0.25, 0.5, 1.0, 2.0 mg/kg, s.c.) or vehicle. Mucosal prostanoid concentrations were determined using high performance liquid chromotography. Tissue myeloperoxidase activities were measured. The effects of FK506 on superoxide radical formation by neutrophils in both rats and humans were also estimated in vitro.Results: Administration of FK506 significantly reduced the colonic damage in a dose-dependent manner. Activities of myeloperoxidase and concentrations of 6-keto-prostaglandin Fl1α (6-keto-PGF1α, PGF2α and PGE2 in colonic tissue increased significantly following induction of experimental colitis, however, FK506 did not affect these changes. FK506 reduced stimulant-induced superoxide radical formation by neutrophils in rats and humans. Conclusion: FK506 decreased superoxide radical generation by neutrophils, which might contribute to the lessening of colonic damage in this model.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-2036.1995.tb00385.x
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  • 9
    Digitale Medien
    Digitale Medien
    Implication of nitric oxide synthase activity in the genesis of water immersion stress-induced gastric lesions in rats: the protective effects of FK506 (1996)
    Oxford BSL : Blackwell Science
    Alimentary pharmacology & therapeutics 10 (1996), S. 0 
    Details
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background: Nitric oxide (NO) is a potent cytoprotective substance of gastric mucosa. FK506, an immunosuppressive drug, shows anti-gastric ulcer effects equivalent to famotidine, an H2 blocker, in rats. This study was designed to evaluate the cytoprotective mechanism of FK506 on gastric mucosa in relation to the changes in NO synthase activity. Methods: Gastric lesions were induced in rats by water immersion stress. Changes in NO synthase activity during water immersion stress treatment, and effects of FK506 on NO synthase activity were determined enzymatically. Gastric mucosal interleukin (IL)-1β and IL-2 were measured by immunoradiometric assay. Gastric mucosal blood flow was measured by hydrogen gas clearance technique. Results: FK506 mitigated gastric lesions developed by water immersion stress. Stress-induced lesions were exacerbated by NG-monomethyl-L-arginine (L-NMMA), a specific inhibitor of NO synthase, while sodium nitroprusside, a NO donor, mitigated the lesions. Water immersion stress increased NO synthase activity in the early phase (0.5 h after stress treatment) and decreased it in the late phase (6 h after). Decrease in NO synthase activity in the late phase was significantly mitigated by FK506, though it did not affect changes in NO synthase activity in the early phase. Water immersion stress increased gastric mucosal IL-1β and IL-2 contents 6 h after stress treatment, and these increases were prevented by FK506. FK506 itself did not affect gastric mucosal blood flow. L-NMMA treatment significantly decreased gastric mucosal blood flow. In contrast, gastric mucosal blood flow was significantly increased by sodium nitroprusside. Conclusions: Increase in NO synthase activity might contribute to cytoprotection, and a decrease in activity might be a harmful factor for the gastric mucosa. Preservation of NO synthase activity by FK506 might be involved in FK506's protective effects on the gastric mucosa.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-2036.1996.108279000.x
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  • 10
    Digitale Medien
    Digitale Medien
    Oxidative dehydrogenation of ethane by carbon dioxide over sulfate‐modified Cr2O3/SiO2 catalysts (1999)
    Springer
    Catalysis letters 63 (1999), S. 59-64 
    Details
    ISSN: 1572-879X
    Schlagwort(e): ethane dehydrogenation ; ethylene ; CO2 ; Cr2O3 ; sulfated silica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The oxidative dehydrogenation of ethane into ethylene by carbon dioxide over unsupported Cr2O3, Cr2O3/SiO2 and a series of Cr2O3/SiO2 catalysts modified by sulfate was investigated. The results show that Cr2O3/SiO2 is an effective catalyst for dehydrogenation of ethane and CO2 in the feed promotes the catalytic activity. Sulfation of silica will influence the catalytic behavior of Cr2O3/SiO2 in dehydrogenation of ethane with carbon dioxide depending on the amount of sulfate. Cr2O3/6 wt% SO 4 2- –SiO2 catalysts exhibit an excellent performance for this reaction, giving an ethylene yield of 55% at 67% ethane conversion at 650°C. Characterizations indicate that addition of sulfate changes the bulk and surface properties of Cr2O3/SiO2, promoting the reduction of Cr6+ to Cr3+ and favoring the catalytic conversion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019084030344
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