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  • Scanning electron microscopy
  • Springer  (107)
  • American Chemical Society
  • Wiley
  • 1985-1989  (30)
  • 1975-1979  (77)
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Lasers in medical science 1 (1986), S. 111-115 
    ISSN: 1435-604X
    Schlagwort(e): Argon laser ; Arterial microanastomosis ; Scanning electron microscopy ; Vessel re-endothelialization ; Collagenous fusion ; Vessel repair
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Physik , Technik allgemein
    Beschreibung / Inhaltsverzeichnis: Résumé Anastomoses micro-artérielles au laser argon: étude en microscopie électronique à balayage. Les auteurs réalisent au laser Argon (Coherent 900) une anastomose carotidienne terminoterminale sur une série de 50 rats Wistar de poids moyen de 260 g. Les impacts laser (en moyenne 19) sont de 300 mW de puissance et d'une durée de 5 s chacun, avec un point de focalisation de 150 μm de diamètre. On réalise sur 13 spécimens un examen en microscopie électronique à balayage. L'impact laser induit sur la paroi artérielle une lésion de 100 μm de large avec une légère nécrose de coagulation de la media et de l'adventice. La ligne de suture est re-endothélialisée dès le quatrième jour, alors qu'une fusion du collagène est observée dans les couches sousendothéliales. L'arrangement longitudinal des cellules endothéliales est retrouvé dés le dixième jour. A long terme, un réseau collagénique serré assure la résistance de la media et un endothélium normal recouvre la ligne de ‘soudure’. Les complications tel que lâchage ou anéurysmes doivent être attribuées aux inconvénients techniques du début de l'expérimentation.
    Notizen: Abstract A carotid end-to-end anastomosis was performed in 50 Wistar rats (mean weight 260 g) by means of a Coherent 900 argon laser. Laser pulses (average 19) of 300 mW power and 5 s exposure time were used, the beam being focused to form a spot of 150 μm diameter. From day 0 to day 210, 13 specimens underwent scanning electron microscope examination. The results show that the laser impact produces a wall injury of 100 μm in width with some coagulative necrosis of the media and adventitia. The line of anastomosis became re-endothelialized within four days, at which time collagen fusion was observed in the subendothelial layers. The longitudinal arrangement of the endothelial cells was restored by day 10. In the long term, a thick collagenous meshwork maintained the strength of the media, while normal endothelium covered the anastomosis. Complications such as disruption and aneurysm formation were attributed to technical problems.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 4 (1987), S. 3-7 
    ISSN: 1432-0789
    Schlagwort(e): Azospirillum lipoferum ; Mucigel ; Oryza sativa ; Root colonization ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Seedlings of rice (IR42 and IR50) were aseptically dipped into Azospirillum lipoferum strain 34H suspension under dark, and the presence of bacteria on the differentiating regions of rice roots was observed by scanning electron microscopy. The bacterium did not colonize the root tips of IR42, while it colonized this region in the case of IR50, within 24 h after inoculation. In the early stages, most of the bacteria were embedded in the ruptured mucigel below the root cap cells of IR42. Mucigel was hardly detectable in IR50. While the root hair primordia of IR50 were colonized heavily with the bacterium within 24 h, the root hairs of IR42 were colonized 48 and 72 h after inoculation. This phenomenon in relation to plant varietal differences was discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 181 (1977), S. 31-40 
    ISSN: 1432-041X
    Schlagwort(e): Cell migration ; Mesoderm ; Gastrulation ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary At the end of gastrulation, the lateral mesoderm of amphibian embryos migrates ventrally between the ectoderm and the endoderm. The present study is an examination of the morphology of the leading cells of the mesodermal sheet and of the substratum over which they move (the inner surface of the ectoderm). The cells of the leading edge of the mesoderm are generally round, with very short and narrow flattened projections in the forward direction. These projections do not have a “ruffled” morphology, regardless of whether fixation is carried out before or after the ectoderm and mesoderm are dissected away from the endoderm. The inner surface of the ectoderm is covered with fine (450–500A) filamentous extracellular material and the ectoderm cells sometimes extend cytoplasmic processes (approx. 0.1 μ wide) onto the leading surface of the mesoderm or onto adjacent ectoderm cells. These studies indicate that the morphology of cell migration in amphibians is closer to that seen inFundulus than to that characteristic of chick or mammalian cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 27 (1979), S. 33-40 
    ISSN: 1432-0827
    Schlagwort(e): Chick embryo ; Bone ; Organ culture ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The study describes the ultrastructure of the mineralized portion of chick tibiae from 10 days in ovo to 2 days post-hatch. At 10 days a single mineralized cylinder surrounds the diaphysis. On its outer surface columnar trabeculae join to form ridges parallel to the long axis of the bone. These ridges are covered by another cylinder and form the haversian canals. At 11 days vascular invasion of the marrow cavity occurs and resorption of the endosteal surface begins. This type of periosteal deposition and endosteal resorption is repeated during and subsequent to embryonic development. The mineralized portion of 10-day chick tibiae cultured for 2 days in modified BGJ medium was compared with 10-, 11-, and 12-day tibiae in ovo. Cultured tibiae were similar in length and calcium content to 11-day tibiae in ovo. The form of mineral deposited in ovo and in culture was the same, namely, aggregates of spherical mineral clusters. Differences in culture included the following: (a) few concentric cylinders were deposited as compared with tibiae in ovo; (b) trabeculae were not arranged in rows and ridges in culture; (c) osteocytic lacunae were restricted to bases of trabeculae rather than uniformly distributed as in ovo; and (d) the endosteal surface of tibiae in culture appeared etched.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 26 (1978), S. 237-241 
    ISSN: 1432-0827
    Schlagwort(e): Epiphyseal chondrocytes ; Freezefracture ; Scanning electron microscopy ; Cell processes ; Membrane particles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Chondrocytes in epiphyseal cartilage were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) using freeze-fracture techniques. Freeze-fracture replicas showed large numbers of fingerlike, 0.11–0.15 μm diameter, projections from the chondrocyte surface, with numerous 95–180 Å diameter intramembranous particles associated with both the cell membrane surface and these projections. With SEM, these cytoplasmic projections were also obvious, but appeared collapsed into clusters of globular-shaped projections on the surface of the chondrocytes. With freeze-fracture techniques, in which shrinkage artifacts were essentially eliminated, the cytoplasmic projections were often seen in intimate contact with the extracapsular matrix. However, with chondrocytes prepared by both SEM and conventional TEM, there was evidence of shrinkage, the cytoplasmic projections having little contact with the extracapsular matrix. These findings show that the cytoplasmic processes are not artifacts of tissue processing and provide morphological evidence in support of the hypothesis that matrix vesicles are of cellular origin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 25 (1978), S. 75-83 
    ISSN: 1432-0827
    Schlagwort(e): Rat ; Fluorosis ; Enamel ; Scanning electron microscopy ; Low temperature incineration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Sixteen 58-day-old male rats of Wistar strain, with a mean body weight of 179 g, were divided into two equal groups. Each group of eight animals was maintained for 70 days on drinking water, ad lib., containing no fluorine (control group) and 100 ppm of fluorine (experimental group). All specimens examined were obtained from the incisal portions of the incisors. The following types of enamel specimens were prepared for scanning electron microscopy: (1) acid-etched specimens; (2) acid-etched specimens followed by low temperature microincineration; and (3) fractured specimens. The enamel formed during high fluoride exposure showed marked hypocalcification, that is, the crystallite density in the prism core and interprismatic region was lower than that of control animals. The organic substances appeared to increase in these regions. These changes were prominent in the outer and middle enamel layers. Such changes following fluoride administration appear to indicate an inhibition of enamel maturation, that is, an inhibition of the mineral deposition and/or an inhibition of organic matrix withdrawal.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Planta 146 (1979), S. 203-210 
    ISSN: 1432-2048
    Schlagwort(e): Cellulose ; Microfibrils ; Negative staining ; Nicotiana ; Protoplasts ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A study has been made of the wall fibrils produced by tobacco protoplasts, using scanning electron microscopy in conjunction with negative staining. It has been shown that the fibres seen in scanning electron microscopy correspond to aggregates of microfibrils. These aggregates are only visible where they are lifted clear of the protoplast surface. Negative staining of fixed protoplasts shows that the aggregation of microfibrils into the fibres visible in scanning electron microscopy is probably produced by air-drying. Gentle disruption of microfibrils produces both random broken fragments and bundles of short pieces of fibrillar material about 60 nm in length. This material is present in undisrupted young walls, but not in undisrupted older walls. The microfibrils in young walls seem much more fragile and liable to breakage than those in older walls. These results are discussed in terms of the interpretation of scanning electron microscope images and the mechanism of cellulose microfibril formation by higher plants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Sexual plant reproduction 1 (1988), S. 97-102 
    ISSN: 1432-2145
    Schlagwort(e): Generative cell ; Isolation ; Scanning electron microscopy ; Immunofluorescence ; Video-enhanced microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Generative cells were isolated from the pollen grains of three angiosperm species by a method similar to that previously reported for Haemanthus katherinae (Baker). Both the external appearance and the internal structure of the isolated generative cells were observed by light and scanning electron microscopy. The dynamic changes occurring in the cells after they had been liberated from the pollen grains were recorded by video-enhanced microscopy. The distribution of microtubules in the isolated cells was revealed by immunofluorescence.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 112 (1977), S. 123-126 
    ISSN: 1432-072X
    Schlagwort(e): Bandeiraea simplicifolia ; Schizosaccharomyces pombe ; Colloidal gold ; Cytochemistry ; α-Galactomannan-lectin ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Galactomannan was localized by scanning and transmission electron microscopy on the cells and cell walls of Schizosaccharomyces pombe. The markers were prepared from colloidal gold granules labelled with an α-galactopyranosyl-binding lectin isolated from the seeds of Bandeiraea simplicifolia. Part or all of this α-galactomannan was present in the outer layer of the cell wall and was uniformly distributed even on the fission scars.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 109 (1976), S. 9-14 
    ISSN: 1432-072X
    Schlagwort(e): Candida utilis ; Saccharomyces cerevisiae ; Colloidal gold ; Cytochemistry ; Mannan ; Plasma membranes ; Scanning electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The β(1→3)glucanase of Basidiomycete QM 806 was used to prepare Saccharomyces cerevisiae and Candida utilis protoplasts. Plasma membranes isolated from S. cerevisiae contained a small amount of mannose and traces of glucose and ribose. Randomly distributed α-mannan was detected by scanning electron microscopy at the surface of prefixed protoplasts using colloidal gold labelled with Concanavalin A as a marker. C. utilis protoplasts were also marked with anti-mannan antibodies. Again the distribution of mannan was random. This experiment indicated also that plasma membrane mannan has the same immunochemical determinants as cell wall mannan. It is hypothesized that mannan is mainly located in the outer layer of plasma membranes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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