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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 3095-3101 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Complexing of 5dn impurities from supersaturated solutions in silicon occurs during thermal processing at intermediate temperatures subsequent to fast or retarded quenching. Doping of silicon with 5dn transition-metal ions in a wet chlorine-containing atmosphere provides the formation of various complex defects, which differ from those formed after doping under protecting conditions. As an example a 6-platinum cluster of trigonal symmetry is presented. The analysis of electron-paramagnetic-resonance data uniquely reveals six geometrically equivalent platinum ions strongly interacting with probably two silicon atoms. A tentative model assumes the introduction of hydrogen during the high-temperature surface reaction. Passivation of the platinum acceptors might be the condition for the formation of the clusters at intermediate temperatures. The formation of similar clusters at appropriate temperatures would explain the higher thermal stability of high-temperature passivation, recently reported.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 3435-3444 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A monoclinic 1-platinum defect recently detected was investigated more thoroughly by electron paramagnetic resonance (EPR). The defect is one of the dominating defects in platinum doped silicon. With a perfect reproducibility it is observed in samples prepared from n-type silicon as well as from p-type silicon, in float zone (FZ) silicon as well as in Czochralski (Cz) silicon. Its concentration varies with the conditions of preparation and nearly reaches that of isolated substitutional platinum in Cz silicon annealed for 2 h at 540 °C after quenching from the temperature of platinum diffusion. Because of its concentration which in Cz-Si exceeds that in FZ-Si the defect is assumed to be oxygen-related though a hyperfine structure with 17O could not be resolved. The defect causes a level close to the valence band. This is concluded from variations of the Fermi level and from a discussion of the spin Hamiltonian parameters. In photo-EPR experiments the defect is coupled to recently detected acceptorlike self-interstitial related defects (SIRDs); their level position turns out to be near-midgap. These defects belong to the lifetime limiting defects in Pt-doped Si. © 1996 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 82 (1997), S. 3456-3461 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this article, we report about complexes in silicon investigated by electron paramagnetic resonance (EPR). In silicon doped with C and Pt we detected two different complexes: cr-1Pt (cr: carbon-related, 1Pt: one Pt atom) and cr-3Pt. The complexes have similar EPR properties. They show a trigonal symmetry with effective g-values geff,⊥=2g⊥(approximate)4 and geff,||=g||(approximate)2 (g⊥, g|| true g-values). The g-values can be explained by a spin Hamiltonian with large fine-structure energy (electron spin S=3/2) and smaller Zeeman interaction. The participation of platinum in the complexes is proved by the hyperfine interaction. From experiments with varying carbon concentration we conclude that the complexes contain carbon. Atomistic models based on the Watkins vacancy-model for substitutional Pt were developed. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz 43 (2000), S. 770-776 
    ISSN: 1437-1588
    Keywords: Schlüsselwörter Gastroenteritisviren ; Hepatitis-A-Virus ; Hepatitis-E-Virus ; infektiöse Diarrhö ; lebensmittelübertragende Viren ; Norwalk/Norwalk-like Viren ; Rotavirus ; Virusübertragung ; Keywords Gastroenteritis viruses ; Hepatitis A virus ; Hepatitis E virus ; Infectious diarrhoea ; Foodborne viruses ; Norwalk/Norwalk-like viruses ; Rotavirus ; Virus transmission
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Until the 1970s, diagnostic methods for infectious diarrhoea were limited to bacteria and parasites, and the causative agent could be identified only in a few cases. But the causes of major foodborne diseases include bacteria, parasites and viruses as well. Unlike bacteria, viruses cannot multiply outside of their specific host. They remain infectious especially in conditions, such as refrigeration, designed to maintain good food quality. Viruses transmitted via food include the hepatitis-inducing viruses A and E, the gastroenteritis viruses e. g. Norwalk and Norwalk-like viruses, Rota- and Astrovirus, Adenovirus and some of the Enteroviruses. Foodborne viruses are transmitted enterically. They are shed by faeces or during vomiting and infect by being ingested (faecal-oral, aerogene-oral). Due to the very high infectivity most of the outbreaks were reported for institutional settings like schools, children's day-care and geriatric facilities and hospitals. Proper conditions of hygiene, and exclusion of sick persons from handling food are important preventive measures to avoid faecal contamination of food.
    Notes: Zusammenfassung Bis in die 70er Jahre war die Diagnostik von infektiösen Diarrhöen auf den Nachweis von Bakterien und Parasiten beschränkt, und auslösende Erreger konnten nur in einigen Fällen ermittelt werden. Verbesserte Nachweismethoden zeigten, dass Lebensmittelinfektionen neben Bakterien und Parasiten zu einem großen Teil durch virale Erreger hervorgerufen werden können. Im Gegensatz zu den Bakterien können sich Viren nicht außerhalb eines lebenden Wirtes vermehren, bleiben aber besonders unter gekühlter Lagerhaltung lange Zeit infektiös. Zu den Lebensmittel-übertragbaren Viren gehören das Hepatitis A- und E-Virus, Gastroenteritisviren wie die Norwalk/Norwalk-like, Rota- und Astroviren, aber auch Adenoviren sowie einige Enteroviren. Ihre Verbreitung erfolgt auf fäkal-oralem bzw. aerogen-oralem Weg. Aufgrund ihrer hohen Infektiosität kann es besonders in Gemeinschaftseinrichtungen wie Schulen, Kindertagesstätten, in Alten- und Pflegeheimen sowie in Krankenhäusern zu Massenausbrüchen kommen. Um eine fäkale Verunreinigung von Lebensmitteln zu vermeiden, ist die exakte Einhaltung von Hygienevorschriften und der Ausschluss von erkrankten Personen von der Lebensmittelbereitung besonders wichtig.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1440
    Keywords: Nicotine ; Metabolism ; Lung ; Liver ; Phenobarbital ; Cytochrome P-450
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The metabolic fate of cotinine, the major metabolite of nicotine, was studied in phenobarbital-induced and non-induced isolated perfused rat lung and liver and in isolated hepatocytes of rats and mice. The non-induced lung tissue showed low cotinine metabolizing capacity while the perfused liver was approximately four times more active. After phenobarbital pretreatment the metabolism of cotinine was increased eight-fold in the intact liver. A substantial increase in cotinine metabolism was also found in isolated hepatocytes from PB-induced rats and in cultured mouse hepatocytes grown in a medium supplemented with PB. This was paralleled by an increased formation of cotinine-N-oxide which could be inhibited by 100 μM metyrapone. In contrast, the pulmonary elimination of cotinine was not affected by PB. A dominant role of primary N-oxidation of nicotine compared to C-oxidation was apparent in non-induced rat liver. After PB treatment the rate of nicotine-N′-oxide formation dropped markedly while the cotinine related pathways were increased causing an inversion of the N- to C-oxidation ratio. In the lung, cotinine formation was the preferred metabolic pathway of nicotine already in non-induced organs. The pattern of nicotine metabolites was not altered by PB induction. In conscious PB-induced rats receiving nicotine orally or intravenously, 3′-hydroxycotinine was found as the main urinary metabolite of nicotine while only a small fraction was excreted as cotinine-N-oxide. This discrepancy between the profile of nicotine metabolites in perfused liver and lung and in the urine in vivo indicates that extrahepatic organs other than the lung may be important sites of cotinine metabolism.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 69-70 (Aug. 1999), p. 209-214 
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 32-33 (Dec. 1993), p. 207-212 
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 6-7 (Jan. 1989), p. 329-334 
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 143-147 (Oct. 1993), p. 1659-0 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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