169,736 research outputs found

    Dynamics of secretion

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    In this short review, kinetic aspects of exocytosis are discussed. A special emphasis is put on recent data that highlight dynamic differences between neurotransmission and other forms of secretion

    Transforming activity of DNA extracted from BKV-transformed hamster cells after passages in culture

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    Primary fetal rat fibroblasts (FRF cells) were transfected with DNA extracted from BKV-transformed hamster kidney cells at low passage after transformation (HKBKlp cells) and at high passage after transformation (HKBKhp cells). Two transformed rat cell lines were obtained, FRF-DNA-HKBKlp cells and FRF-DNA-HKBKhp cells, transformed by DNA extracted from HKBKlp cells and HKBKhp cells, respectively. They were characterized by a number of biological properties and by tumorigenicity and metastatic ability in newborn hamsters. The two transformed FRF cell lines exhibited exactly inverted properties in comparison with HKBK cells, in particular FRF-DNA-HKBKlp cells showed a low level of nuclear T antigen and a diffuse appearance of TSTA at the cell surface, whereas FRF-DNA-HKBKhp cells demonstrated a high level of T antigen and the capping of TSTA in the cell membrane. The tumorigencity and the metastatic ability were greater with FRF-DNA-HKBKlp cells, while FRF-DNA-HKBKhp cells appeared to be less tumorigenic and metastatic in newborn hamsters

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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