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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 62 (1987), S. 3785-3790 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A combination of deep level transient spectroscopy (DLTS) and electron spin resonance (ESR) measurements was used to determine the energy level of substitutional manganese in silicon. Samples of p-type silicon were subjected to a copper-manganese codiffusion. Successfully prepared samples show the typical ESR signal of substitutional manganese with a single positive charge. The Hamiltonian parameters g=2.029 and A=−62.7×10−4 cm−1 are different from those for negatively charged interstitial manganese. The DLTS measurements reveal an energy level of M1=0.39 eV above the valence-band edge for the substitutional manganese. Because of the codiffusion of Cu also the previously reported levels C1=0.098 eV, C2=0.22 eV, and C3=0.41 eV were found. The combination of ESR and DLTS results allowed a conclusive identification of the defect level M1 and provided no evidence for ordinary amphoteric or negative U behavior in the lower half of the band gap. Furthermore, isothermal and isochronal annealing experiments were performed which support the conclusion that the defect level M1 orginates from substitutional manganese in p-type silicon.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Solid State Communications 47 (1983), S. 223-226 
    ISSN: 0038-1098
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Solid State Communications 27 (1978), S. 867-871 
    ISSN: 0038-1098
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Planta 192 (1993), S. 118-124 
    ISSN: 1432-2048
    Keywords: Cell cycle ; Differentiation ; Flow cytometry ; Histone ; Proliferating cell nuclear antigen ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cell-cycle progression of germinating embryos of maize (Zea mays L.) was studied from 0 to 72 h after the start of imbibition using DNA flow cytometry on isolated nuclei, and analyses of thymidine kinase activity, histone biosynthesis and levels of proliferating cell nulcear antigen (PCNA). At the start of germination, 75% of the cells were in G1, but this population had decreased to 25% by 72 h. The concomitant increase of cells in S-phase did not occur continuously, but stepwise, indicating that during germination most of the cells enter S-phase as a partially synchronized population. Within the initial 60 h of embryo germination the cells passed through one S-phase; the start and duration of this period of replicative DNA synthesis was further substantiated by the analysis of S-phase-associated events, the biosynthesis of core histones and the enzyme activity of thymidine kinase, which both began to increase at about 12 h after the start of differentiation. Thymidine kinase fluctuated periodically during germination with a transient maximum at 30 h and a second peak at 72 h; histone biosynthesis was not detectable until 12 h after the start of germination. The levels of PCNA protein closely resembled the pattern of thymidine kinase during germination. Together with the cytometric data this allows a clear assignment of cell cycle events to different times of embryo differentiation.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-2307
    Keywords: Human Sertoli cells ; Intermediate filaments ; Cytokeratin ; Vimentin ; Desmin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The intermediate filament of mature human Sertoli cells is vimentin. A co-expression of vimentin together with cytokeratin has been demonstrated in Sertoli cells during embryonal development and under pathologic conditions in adult testes. We analysed the presence of vimentin, cytokeratin, and desmin in Sertoli cells of fetal testes (n=20), in seminiferous tubules of cryptorchid testes (n=10) and adjacent to testicular germ cell tumours (n=47) using specific monoclonal antibodies and single and double-labelling immunohistochemistry. During embryonal development prominent cytokeratin expression disappears after the 20th week of gestation. Interestingly, we also found desmin in immature intratubular Sertoli cells between weeks 11 and 14. In adult cryptorchid testes and in peritumour tubules, desmin was also prominently present in Sertoli cells in the vast majority of the cases investigated, as well as vimentin and cytokeratin co-expression. This first description of desmin immunoreactivity may shed some light on the ontogeny of human Sertoli cells and demonstrates that this cell type is able to express three types of intermediate filaments in a complex manner.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-2307
    Keywords: Carcinoids ; Bronchial carcinoids ; Intestinal carcinoids ; Chromogranin A ; Chromogranin B ; Secretogranin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Carcinoid tumours (bronchial and intestinal) were analyzed by immunoblotting for the presence of chromogranin A, B and secretogranin II. In all tumours an antigen corresponding in electrophoretic behaviour to adrenal chromogranin A was present. Lung carcinoids (3 out of 5) contained a relatively high concentration of a proteoglycan form of this antigen in addition. Chromogranin B was found in all tumours. In one and two dimensional immunoblotting it appeared identical to the corresponding adrenal antigen. Secretogranin II was also present, however concentrations (especially in intestinal carcinoids) were low and variable. Furthermore, in intestinal tumours it differed from the adrenal antigen by having a slightly higher molecular size and a more alkaline pI. Immunohistochemistry revealed that the tumour tissues stained positively for all three antigens. For secretogranin II the staining in intestinal tumours was relatively weak and quite variable. These results should provide a defined basis for immunohistochemical screening of carcinoids for the chromogranin/secretogranin antigens.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 416 (1990), S. 277-279 
    ISSN: 1432-2307
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-2307
    Keywords: Nucleolar organizer regions ; Silver staining ; Image analysis ; Cell cycle ; Proliferation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Detailed investigation of cell growth and nucleolar organizer region associated argyrophilic proteins (Ag-NORs) is necessary to asses a possible impact of Ag-NOR quantification on the diagnosis and prognosis of tumours. In this study, cellular proliferation of the transitional-cell carcinoma cell line HOK-1 was modulated over a period of 11 days by starvation and subsequent medium addition. Proliferation was determined daily by DNA flow cytometric estimation of S-phase fraction (SPF) and mitotic index (MI) calculation. The number and area of interphase Ag-NORs were quantified by automated image analysis daily and the number of Ag-NOR bearing chromosomes in metaphase was counted. In interphase nuclei, Ag-NOR area showed a highly significant correlation with SPF (p〈0.0001) whereas interphase Ag-NOR number showed significant correlation with MI (p〈0.05). A positive relationship between the number of Ag-NOR bearing chromosomes in metaphases and cellular proliferation was also observed. There is variability in Ag-NOR quantity during interphase and metaphase depending on growth conditions in vitro. Correlations of the number of interphase Ag-NORs with the MI on one hand and Ag-NOR area with SPF on the other provide further evidence that distribution and quantity of Ag-NORs are strongly influenced by the cell cycle phase within the structural-functional unit of the nucleolus.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-1963
    Keywords: Schlüsselwörter Urothelkarzinom ; Carcinoma in situ ; Harnblase ; Urinzytologie ; Key words Transitional cell carcinoma ; Carcinoma in situ ; Urinary bladder ; Urinary cytology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The surgical pathology of biopsies or electro-resection specimens taken from clinically sus-picious or overt tumors in the urinary bladder encompasses the evaluation of a few parameters. This should allow the segregation of bladder tumor patients into subgroups with distinct clinical features and biological behavior, thus providing a rationale for choos-ing the best available therapy. In essence, the pathologist’s role entails a careful morphologic assessment of the primary tumor, including evaluation of the histologic type, the growth pattern, the tumor grade, the tumor stage, and finally the presence and type of primary or tumor-associated flat intraurothelial lesions. Whereas the growth pattern of a lesion can be readily recognized, the correct grading and staging of papillary tumors are often more dependent on the complexity of the individual case and the experience of the pathologist due to the inherent subjectivity of the field and a lack of standardized criteria. These problems of intra- and interobserver variability are intimately cou-pled with the characteristics of the material, that is, bad orientation and tangential sectioning, thermal injury, crush and fixation artifacts, and limitations of the size of the samples. The correct evaluation and interpretation of flat intraurothelial lesions suffer from similar difficulties and are further complicated by a confusing categorization and terminology. Although new modalities and molec-ular approaches have been introduced in recent years in an effort to overcome some of these obstacles, morphology still remains the most effective means to assess the bio-logical behavior and prognosis of urothelial bladder cancer. The present article therefore addresses some of the diagnostically and clinically most relevant controversies and aims to give some useful hints for the evaluation of the above-mentioned morpho-logical parameters. In addition, it adds some remarks on the morphological basis and diag-nostic validity of urinary cytology in primary diagnosis and, more importantly, monitoring of bladder cancer patients.
    Notes: Zusammenfassung Der Alltag des Pathologen im Umgang mit Gewebeproben aus der Harnblase bei klinischem Tumorverdacht oder bei eindeutig verifizierten Neoplasien wird durch wenige, aber vielfach nicht einfach lösbare Fragen und Probleme bestimmt, die für den betroffenen Patienten von wesentlicher prognostischer und therapeutischer Bedeutung sind. Für urotheliale Tumoren sind dies im wesentlichen die verbindliche histologische Diagnose des Wachstumsmusters, die Feststellung von Malignitätsgrad und Stadium und die Präsenz primärer oder tumorassoziierter intraurothelialer Neoplasien bzw. deren Abgrenzung von reaktiven Urothelveränderungen. Während die Diagnose exophytischer, solid infiltrierender und flacher Urothelläsionen zumeist wenig Schwierigkeiten bereitet, unterliegen das verläßliche und reproduzierbare Grading und Staging von Urothelkarzinomen oftmals mehr der Subjektivität und Erfahrung des Befunders als nachvollziehbaren und standardisierten Kriterien. Die Art der Biopsie- bzw. Gewebeentnahme – in den meisten Fällen durch eine Elektroresektion der Läsion – macht diese Aufgaben nicht gerade leichter. Die gleichen Problemfelder ergeben sich übrigens auch für die histologische Diagnostik intraurothelialer Veränderungen, zusätzlich kompliziert durch eine verwirrende Terminologie. Der vorliegende Artikel versucht, einige dieser diagnostisch und klinisch relevanten Kontroversen aufzugreifen und zumindest für die oben genannten Bereiche praktisch nützliche Hinweise zu geben. Ergänzt wird dieser Versuch durch eine knappe Zusammenfassung der Grundlagen und Wertigkeit der Urin- und Blasenspülzytologie, die weniger in der Primärdiagnostik als vielmehr in der Nachsorge und Überwachung von Tumorpatienten ihre sinn-volle Anwendung findet.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Carbohydrate Research 145 (1985), S. 1-11 
    ISSN: 0008-6215
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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