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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 421-424 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The existence of long-range potential fluctuations (PF) in compensated semiconductors results from the nonuniform distribution of ionized impurities, and it was observed that PF can be erased when the material is submitted to a critical field, the value of which depends on the sample. Data on the temperature and time dependence of the discharge current of a semi-insulating GaAs crystal, which has been submitted to a critical field, are reported. The discharge current decreases with a time constant equal to the reverse of the electron emission coefficient of deep centers brought out of equilibrium by the external field. Not only the activation energy of the emission coefficient, but also the density of the deep center species responsible for the discharge current, can be determined from the data. In the case of the GaAs sample studied in this paper, the observed discharge current results from the return to equilibrium of the Cr acceptor center HL1.
    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 60 (1986), S. 1059-1064 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Data on ac and dc field dependence of the conductivity of semi-insulating GaAs crystals are reported. The existence of long-range potential fluctuations in these samples has been previously reported. Field-enhanced conductivity results from the decrease of the maximum depth of the wells due to barrier lowering, up to a critical field at which the effect of potential fluctuations disappears. The transient behavior is also discussed.
    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 58 (1985), S. 2646-2650 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Complex conductivity measurements of unannealed and annealed semi-insulating GaAs crystals are reported. A model of fluctuations of well-defined magnitude superimposed to a Gaussian distribution accounts for the σac ∝ ω2 dependence observed above 106 Hz in some unannealed samples. The effect of annealing on the magnitude of long-range potential fluctuations and on the average carrier density is analyzed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford : Blackwell Science Ltd
    Anaesthesia 54 (1999), S. 0 
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0021-9673
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of environmental contamination and toxicology 60 (1998), S. 944-948 
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    International journal of colorectal disease 12 (1997), S. 342-343 
    ISSN: 1432-1262
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-1262
    Keywords: Key words Fat clearance ; Immunohistochemistry ; Colorectal carcinoma ; Prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Afin d'évaluer la signification de micrométastases en relation avec le taux de survie, les pièces opératoires de 48 patients porteurs d'un cancer colorectal ont été analysées après clearance de la graisse périrectale. Le nombre et la taille des ganglions lymphatiques contenant des métastases et la signification de ces micrométastases en relation avec la survie des patients ont été déterminés. Nous avons trouvé que la majorité des métastases lymphatiques (71.8%) avaient 5 mm ou moins de diamètre et que leur taille n'avait pas d'effet sur la survie. Des colorations immunohistochimiques des ganglions lymphatiques ont révélé que 15 des 25 patients diagnostiqués comme présentant un cancer au stade B de Dukes sur des colorations de routine contenaient en fait des micrométastases et que 86% de celles-ci mesuraient moins de 5 mm de diamètre. La survie de ce sous-groupe a été considérablement plus mauvaise que celle de patients au stade B de Dukes sans micrométastases. Aucun des trois patients à un stade A de Dukes ne présentait de micrométastases. Etant donné que la plupart des métastases et micrométastases surviennent sur des ganglions lymphatiques de 5 mm et moins et que ces dernières peuvent aisément être méconnues lors d'examens de routine, nous proposons que la clearance de la graisse périrectale et une analyse immunohistochimique de routine des cancers au stade de Dukes B améliorent la prédiction de survie des patients opérés d'un cancer colorectal.
    Notes: Abstract To evaluate the significance of micrometastases in relation to survival rate, specimens from 48 colorectal carcinoma patients were analysed after fat clearance. The number and size of the lymph nodes harbouring metastases and the significance of micrometastases for patients' survival were assessed. We found that although the majority of metastatic lymph nodes (71.8%) were 5 mm or less in diameter, their size had no effect on survival. Immunohistochemical staining of lymph nodes revealed that 15 of 25 patients with Dukes' stage B diagnosed by routine staining had micrometastases, 86% of these lymph nodes being less than 5 mm in diameter. The survival rate of this subgroup was found to be considerably poorer than that of Dukes' stage B patients with no micrometastases. None of the three patients with Dukes' stage A carcinoma had micrometastases. Since most of the metastases and micrometastases occur in lymph nodes of 5 mm and less and can be easily missed by routine examination, we suggest that fat clearance and routine immunohistochemical analysis of Dukes' stage B improve the prediction of outcome of colorectal cancer patients.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 106 (1986), S. 55-63 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Extraction of WO 4 2− and ReO 4 − by Adogen-381, tricaprylmethylammonium chloride, Hyamine 10-X, trioctylphosphine oxide or dibenzylsulphoxide in xylene from HNO3, HCl or H2SO4 acid medium was investigated. Based on the separation factors obtained, the separation of ReO 4 − from WO 4 2− was elucidated. ReO 4 − was separated from WO 4 2− in high radiochemical purity: 〉99.9% by three successive extractions and strippings using Adogen-381 from HCl or HNO3 acid medium.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 23 (1987), S. 83-85 
    ISSN: 1612-1112
    Keywords: Capillary gas chromatography ; Amino acid enantiomers ; Fluoroesters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An optimum gas chromatographic separation of all protein amino acids in one run on capillaries coated with Chirasil-Val is difficult to achieve. Overlap of enantiomers of different amino acids may occur because the relative retention times depend upon the overall polarity of the stationary phase, the film thickness and the actual temperature programm. Employment of different derivatives formed by esterification with isopropanol, n-propanol, isobutanol and n-butanol and by acylation with trifluoroacetic, pentafluoropropionic and heptafluorobutyric anhydrides yields patterns of relative elution of all amino acid enantiomers. Thus, even critical pairs of amino acid enantiomers can be separated or shifted in their relative retention times. All amino acid enantiomers can be separated and quantitatively estimated.
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