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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Abacus 16 (1980), S. 0 
    ISSN: 1467-6281
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Economics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    R & D management 11 (1981), S. 0 
    ISSN: 1467-9310
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Economics
    Notes: Respondents claimed that European effort on basic research rnay have so diminished that the long-term competitiveness of its industries is endangered. They saw a major role for the Commission in redressing this imbalance. There was little support for Commission sponsorship of applied industrial research. Some respondents felt that this could even be counter-productive by diluting effort in areas seen as important by industrial management. A role was seen for the commission in supporting more research on the legislative context and general environment in which industry operates (‘contextual research’). The need for such research imposes a growing burden on industry and diverts scarce resources from work directly related to competitiveness.A study sponsored by the Commission of the European Communities aimed to identify the types of R & D activity in aid of European industry that the Commission might support over the next three or four years. The findings are based on interviews with senior managers from some fifty firms, representing eight sectors of manufacturing industry in five European countries.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 383 (1982), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 4 (1981), S. 317-331 
    ISSN: 0148-7280
    Keywords: spermatogenesis ; plasma membrane proteins ; cell surface iodination ; Two-dimensional electrophoresis ; mouse ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Cell surface polypeptides of mouse pachytene spermatocytes and round spermatids (steps 1-8) have been iodinated using 1,2,3,6,tetracholoro-3α, 6α-diphenylglycouril (IODOGEN). Labeled proteins have been assayed using two-dimensional polyacrylamide electrophoresis and radioautography. Purified plasma membranes, prepared from both spermatocytes and spermatids after the iodination of intact cells, exhibit 25-30 polypeptides which label reproducibly. No significant qualitative differences are noted in the labeled polypeptide map obtained from each of the purified cell types. Iodinated proteins range in molecular weight from greater than 100k daltons to approximately 40k daltons. The isoelectric points of labeled constituents range from pI 5.7 to 7.2. Three polypeptides represent the major iodinated species: p 94/5.8, p 75/5.9, and p 53/7.1. Comparison with total plasma membrane constituents assayed using Coomassie brilliant blue indicates that many of the radioactively labeled proteins are not present in quantities sufficient to allow ready detection without isotopic techniques. As a result, many of the proteins identified autoradiographically represent newly described surface components of mouse pachytene spermatocytes and round spermatids. The preparation of purified plasma membrane fractions prior to electrophoresis ensures that all iodinated species are in fact cell surface components. Furthermore, experiments designed to assess the vectorial nature of the IODOGEN-catalyzed labeling procedure suggest that most, if not all, of the iodinated species are exposed on the external side of the cell plasma membrane. Therefore, these studies have (1) identified hitherto unrecognized plasma membrane components of mouse pachytene spermatocytes and round spermatids and (2) provided the first available biochemical data concerning the molecular orientation of particular proteins in the surface membranes of developing mouse spermatogenic cells.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 4 (1981), S. 487-498 
    ISSN: 0148-7280
    Keywords: testis ; human ; cell separation ; germ cells ; spermatocytes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Normal adult human testis has been separated using a combination of mechanical and enzymatic procedures to yield a suspension of viable single cells. The predominant cell types comprising this suspension are as follows: primary pachytene spermatocytes (7% of total cells), round spermatids (17%), residual bodies and condensing spermatids (31%), and Leydig cells (15%). Separated human germ cells viewed by Nomarski differential interference microscopy closely resemble mouse spermatogenic cells in relative size and appearance. Isolation of an enriched population of human pachytene spermatocytes has been achieved using unit gravity sedimentation (STA-PUT) according to protocols originally developed for murine tissue. Pachytene cells are enriched to 75% and are contaminated only with Leydig cells and binucleated spermatid symplasts. Ultrastructural examination of isolated human pachytene spermatocytes indicates that these cells, as well as isolated round spermatids, exhibit a normal in situ morphology. Spermatocytes, for example, show numerous synaptonemal complexes, nuclear pores, annulate lamellae, and dictyosome-like saccules. Round spermatids after isolation exhibit peripheral mitochondria, annulate lamellae, developing acrosomes, and other morphological features characteristic of early spermiogenesis. Therefore, enriched populations of human spermatogenic cells seem suitable for analysis using immunofluorescent, autoradiographic, or serological methods. In particular, isolated human spermatocytes should be useful for the analysis of molecular events involved in meiosis and should facilitate investigations concerning the pathophysiology of certain human infertility conditions.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 7 (1983), S. 227-239 
    ISSN: 0148-7280
    Keywords: testis ; human ; spermatogenic cells ; two-dimensional electrophoresis ; marker proteins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Highly homogeneous populations of human pachytene spetmatocytes and round spermatids have been obtained from normal adult testis using unit gravity (STA-PUT) sedimentation. Contaminating Leydig cells have been removed by density centrifugation in discontinuous Percoll gradients to yield resultant germ cell purities of 90-95% for pachytene spermatocytes and 89-96% for round spermatids. The total cellular polypeptide composition of separated human germ cells has been analyzed by two-dimensional polyacrylamide gel electrophoresis to compare 1) human and mouse pachytene spermatocytes (species specificity), 2) samples of human spermatocytes obtained from different individuals (allo specificity), and 3) pachytene spermatocytes and round spermatids from the same patients (stage specificity). Mouse and human germ cells have been found to exhibit extensive homology, but identified marker proteins limited to human spermatocytes include a group of polypeptides at p45/5.9 as well as a protein at p67/5.2. Proteins unique to mouse germ cells include component p65/5.5. Comparisons between different preparations of human pachytene spermatocytes have revealed about 90% electrophoretic homology, but some striking allotypic variations have been noted including the proteins at p45/5.9. Finally, presumptive stage-specific spermatogenic cell markers have been identified including the p45/5.9 polypeptides that are present only in human spermatocytes. Although the physiological roles of particular marker proteins have not yet been determined, the present findings indicate that purified spermatogenic cell populations may be analyzed biochemically to identify constituents important in the regulation of sperm development in man.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Fire and Materials 8 (1984), S. 55-56 
    ISSN: 0308-0501
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Fire and Materials 6 (1982), S. 161-162 
    ISSN: 0308-0501
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Fire and Materials 7 (1983), S. 96-97 
    ISSN: 0308-0501
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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