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  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 596-598 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The energy relaxation process of electrons in GaAs/AlGaAs multiple-quantum-well structures is investigated by time-resolved photoluminescence measurement using an up-conversion technique. The relaxation time becomes shorter as the well width becomes narrower. This means that the two-dimensional nature of electrons plays an important role in energy relaxation. In addition, the intersubband relaxation process is studied under several excitation conditions. The relaxation rate from the n=2 to the n=1 subband is found to be 1.2 ps, which is in good agreement with theoretical calculations.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 293-299 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Time-of-flight and photoluminescence measurements are performed for p-GaAs samples at room temperature to investigate minority electron transport properties under high electric field. Reduction of drift velocity, absence of negative differential resistance, and thermally nonequilibrium states between electrons and holes were observed. These features were different from those for majority electrons and indicate strong dependence on hole concentration. Through studies of the energy loss rate and energy and momentum relaxation times, and by performing Monte Carlo calculations including electron-hole interaction, it is clarified that the energy and momentum transfers by electron-hole interaction have significant effects on minority electron transport property.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 56 (1990), S. 824-826 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Using the time-of-flight method, the drift velocity for minority electrons in highly doped p-GaAs was successfully measured at room temperature. The obtained velocity electric field relationships indicate that the velocity does not decrease but slightly increases and then saturates with increasing hole concentration above 1×1019 cm−3. Such behavior is well explained by the effects of degeneracy, which reduces the electron-hole interaction, and the hole distribution function dependence on electric field from the Monte Carlo calculation.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 2310-2312 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Time-of-flight measurements using a picosecond pulsed laser are made for a p-AlGaAs/GaAs/AlGaAs double heterostructure to successfully obtain the velocity-electric field relationship for photoexcited electrons at room temperature. In the high electric field region, velocity enhancements are observed, which have never been reported until now. Possible mechanisms, which attribute to the velocity enhancement, are also discussed.
    Materialart: Digitale Medien
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  • 5
    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: The hyperplastic changes observed in Helicobacter pylori-associated gastritis have been considered to increase the risk of gastric cancer. The aim of this study was to determine whether cyclooxygenase-2 is involved in the hyperplastic changes in mice infected with H. pylori.〈section xml:id="abs1-2"〉〈title type="main"〉Methods:Seven-week-old, male C57BL/6 mice (n=40) were inoculated with the Sydney strain of H. pylori. Control mice (n=40) were treated with vehicle only. Half of the infected and control mice were fed an experimental diet containing etodolac (10 mg/kg/day) from 1 week after inoculation until the end of the experiment. The thickness of gastric pits, COX-2 mRNA and protein levels, and prostaglandin E2 (PGE2) levels in the gastric mucosa were determined before and 12, and 24 weeks after inoculation.〈section xml:id="abs1-3"〉〈title type="main"〉Results:The thickness of gastric pits, COX-2 mRNA and protein levels, and PGE2 levels were significantly increased at 24 weeks after inoculation of H. pylori compared with the control groups. Treatment with etodolac resulted in significant decreases in PGE2 production and in the thickness of gastric pits in the infected groups at 24 weeks after inoculation.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions:Our findings suggest that COX-2 is involved in the development of hyperplastic gastritis caused by H. pylori infection via the production of PGE2.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background : Proton-pump inhibitors, such as lansoprazole, are metabolized in the liver by CYP2C19 and cannot inhibit acid sufficiently in homozygous extensive metabolizers of CYP2C19.Aim : To examine whether famotidine would increase the cure rates of Helicobacter pylori infection by a standard triple therapy.Methods : A total of 177 H. pylori-positive patients were randomly assigned to either lansoprazole 30 mg b.d., clarithromycin 200 mg b.d. and amoxicillin 750 mg b.d. for 1 week (LCA group; n = 89) or famotidine 20 mg b.d., lansoprazole 30 mg b.d., clarithromycin 200 mg b.d. and amoxicillin 750 mg b.d. for 1 week (FLCA group; n = 88). Famotidine was administered after lunch and before sleep, and the others were after breakfast and dinner. CYP2C19 genotypes were determined by a polymerase chain reaction restriction fragment length polymorphism (PCR–RFLP) method.Results : In the LCA group, the eradication rates for homozygous extensive metabolizers, heterozygous extensive metabolizers, and poor metabolizers were 63%, 87%, and 100%, respectively (P = 0.014). Those in the FLCA group were 85%, 85%, and 100%, respectively (N.S.). The cure rate for homozygous extensive metabolizers in the FLCA group was significantly higher than that in the LCA group (P = 0.035).Conclusion : Famotidine improves the cure rate of H. pylori infection by a triple therapy in CYP2C19 homozygous extensive metabolizers patients.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 18 (2003), S. 0 
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
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  • 8
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The acid inhibitory effect of lansoprazole depends on the S-mephenytoin 4′-hydroxylase (CYP2C19) genotype status. The effect of famotidine is independent of this genotype.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:To investigate the acid inhibitory effects of lansoprazole vs. famotidine during the daytime and night-time with reference to different CYP2C19 genotypes.〈section xml:id="abs1-3"〉〈title type="main"〉Methods:Fifteen healthy volunteers were given 20 mg famotidine twice a day or 30 mg lansoprazole once a day for 8 days. On post-dose day 8, 24-h intragastric pH monitoring was performed.〈section xml:id="abs1-4"〉〈title type="main"〉Results:During the daytime, the intragastric pH with lansoprazole was significantly higher than that with famotidine in the heterozygous extensive metabolizer group, whereas no significant difference was observed in the homozygous extensive metabolizer group. During the night-time, the intragastric pH with famotidine was quite similar to that with lansoprazole in the heterozygous extensive metabolizer and poor metabolizer groups. However, during the night-time, the intragastric pH with famotidine was significantly higher than that with lansoprazole in the homozygous extensive metabolizer group.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusions:An insufficient acid inhibition by lansoprazole during the night-time in the homozygous extensive metabolizer group could be compensated for by famotidine. CYP2C19 genotype testing appears to be useful for predicting the optimal acid inhibitory drug treatment collated with circadian intragastric pH change.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford UK : Blackwell Science Ltd.
    Alimentary pharmacology & therapeutics 16 (2002), S. 0 
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: To investigate the effects of Helicobacter pylori infection and eradication on nutrition.〈section xml:id="abs1-2"〉〈title type="main"〉Methods:The body weight, height, blood pressure, gastric juice pH and fasting serum levels of glucose, total protein, albumin, total cholesterol and triglyceride were measured in H. pylori-positive and H. pylori-negative subjects, and the effect of eradication of H. pylori on these parameters was determined. The development of gastro-oesophageal reflux disease after treatment was also examined. Eight patients underwent a pancreatic function test before and after H. pylori eradication therapy.〈section xml:id="abs1-3"〉〈title type="main"〉Results:The incidence of hypoproteinaemia in H. pylori-positive subjects was significantly higher than that in H. pylori-negative subjects. After eradication of H. pylori, the gastric juice pH values were significantly decreased, and the body weight and serum levels of total cholesterol, total protein and albumin were significantly increased. The incidence of hyperlipidaemia significantly increased and that of hypoproteinaemia significantly decreased in the group with eradication. Pancreatic function improved significantly after eradication of H. pylori. No significant changes in these parameters were observed in the group without eradication. Obese patients had a higher risk of the development of gastro-oesophageal reflux disease after eradication of H. pylori infection.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions:The eradication of H. pylori appears to improve some nutritional parameters.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1095-8649
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Myxobolus artus infection of carp is reported for the first time from Japan. In most cases, it took the form of interfibrillar pseudocysts in the skeletal muscle, some showing abnormal growth, imperfect encapsulation of the parasite by the host connective tissue and irregular development of the ectoplasm. Such atypical pseudocysts probably ruptured before the completion of sporogenesis, causing lysis of adjacent muscle fibres. Intrafibrillar pseudocysts were also present. After spore formation was complete or atypical pseudocytes were ruptured host reaction was initiated. Spores were phagocytosed and transported to the melanomacrophage centres in the kidney, liver, spleen etc. Phagocytosed spores were also observed in the capillaries and epithelial tissues of various organs, suggesting that the spores were transported there from the skeletal muscle through the host vascular system. They are thought to be discharged from the host through the skin and intestine.
    Materialart: Digitale Medien
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