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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 70 (1986), S. 262-268 
    ISSN: 1432-0533
    Keywords: Meningioma ; Psammoma body ; Fine structure ; Matrix vesicle ; Matrix giant body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Psammoma bodies in meningocytic whorls were investigated by electron microscopy. In some whorls, connective tissue fibers were seen and membrane-bound vesicles were contiguous to degenerated cells. Some small vesicles, 0.1 to 0.5 μm in diameter, were outlined by plasma membrane (matrix vesicles), other larger ones, about 1 to several μm in diameter, were invested by a thick wall (matrix giant bodies). Mineralized deposits were frequent in these vesicles and occasionally large masses of mineralized connective tissue fibers (psammoma bodies) were seen. Analysis of the material in the mineralized vesicles and fibers, using an energy dispersive X-ray microanalyzer, showed that both calcium and phosphorous were evident and hydroxyapatite was substantiated using an X-ray differactometer. Psammoma body formation in the meningocytic whorls may represent degeneration in some whorls of the central cells which contain connective tissue fibers, producing cell debris such as membrane invested vesicles. Subsequently, calcification occurs in these vesicles, and the mineralization process extends to neighboring connective tissue fibers. The calcified mass forms a psammoma body.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 67 (1985), S. 219-225 
    ISSN: 1432-0533
    Keywords: Inner membrane ; Chronic subdural hematoma ; Dural border cell ; Arachnoid cell ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electron-microscopic findings of inner membranes of chronic subdural hematomas showed multilayered tiers of flattened cells. The basis characteristics of these cells were similar to dural border cells in the human dura-arachnoid interface layer. The cells covering the hematoma surface had indented nuclei with a prominent nucleolus and were abundant in enlarged rough ER, glycogen granules, lipid droplets, and caveolae. The cells in the intermediate layer had thin cytoplasmic extensions containing tonofilaments, which were oriented almost parallel to the long axis of inner membranes. The cells facing the arachnoid surface sometimes showed disintegration of cellular organelles and dissolution of nuclear chromatin. Between these cells and the tiers was an increased amount of extracellular substance, such as collagen fibrils, clastins, and finely granular material, which were often intermingled with blood pigments or fibrins, especially toward the arachnoid surface. In two of the ten cases studied, there was a syncytial mass of arachnoid cells which reinforced the arachnoid surface of inner membranes. Conceivably, a primary extravasation of blood within the dura-arachnoid interface layer may cleave a few tiers of dural border cells, which envelope the inner surface of the hematoma, proliferate, and later on form inner membranes.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 66 (1985), S. 163-166 
    ISSN: 1432-0533
    Keywords: Meningioma ; Psammoma bodies ; Perivascular area ; X-ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Psammoma bodies at the perivascular area in five cases of meningioma were examined with the electron microscope. In general, meningocytic cells invest the outer aspect of blood vessels, which are constituted by multilayered basal laminae, collagen fibers, microfibrils, and pericytes. Remnants of degenerated cells are observed in some areas of the perivascular space. Matrix vesicles and matrix giant bodies with or without mineralized deposits are also present in those areas. Energy disperisve, X-ray microanalysis evidenced the presence of both calcium and phosphorus (probably hydroxyapatite) mineralized precipitates. Production of psammoma bodies in the perivascular area may indicate that matrix vesicles and matrix giant bodies are derived from degenerated cells, which then sequestrate hydroxyapatite crystals to form psammoma bodies.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 71 (1986), S. 100-105 
    ISSN: 1432-0533
    Keywords: Ependymona ; Fine structure ; Abnormal cilia ; Giant cilia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Abnormal cilia were frequently exposed in a malignant ependymoma of the cerebellar vermis by an electron microscope study. Among these erratic cilia, compound cilia, huge axoneme with bizarre shapes, were repeatedly observed. These giant cilia commonly had random orientation of many microtubular doublets as well as complicated cavities in their granular ciliary matrix. Additionally, abnormal cilia of normal-sized axoneme showed diversified arrangement of peripheral doublets and central singlets. The formation process of these abnormal cilia is discussed.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 71 (1986), S. 19-25 
    ISSN: 1432-0533
    Keywords: Arachnoid villi ; Psammoma body ; Matrix granule ; Matrix vesicle ; Matrix mineral
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structure of the human arachnoid villi was studied to clarify the origin of psammoma bodies. Within the villous surface layer, collagen fibrils and fine granular material clustered forming microcores of variable caliber measuring up to 10 μm. An early stage of psammoma body formation was seen more frequently in these villous microcores than in the meningocytic whorls. The villous microcores contained a large number of membrane-free matrix granules as well as a small number of membranebound matrix vesicles and matrix minerals. The matrix granules were irregularly oval structures with electronlucent halo, measuring 0.05–0.70 μm in diameter. Hydroxyapatite crystals were frequently precipitated within and around the matrix granules which aggregated with calcifying matrix vesicles and matrix minerals. Numerous calcifying matrix granules were present within and around enlarging psammoma bodies. The matrix granules may serve as the principal calcification nidi of psammoma bodies in the human arachnoid villi. The possible mechanisms of matrix granule biogenesis are extrusion of preformed arachnoid cell structures or secretion of fine granular material with its extracellular assemblage.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 2764-2766 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: High-power (2.2 W) cw operation has been achieved in a (111)-oriented GaAs/AlGaAs graded-index separate-confinement-heterostructure single-quantum-well laser with the 100-μm wide stripe geometry. High differential quantum efficiency of 81% has been obtained up to ∼1.2 W, and high total power-conversion efficiency of 46% has been achieved at 1.5 W.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 89 (1985), S. 622-625 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 142-144 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Polycrystalline silicon (poly-Si) films were prepared on a fused quartz substrate at 700 °C by low-pressure chemical vapor deposition (LPCVD) and plasma-enhanced CVD (PECVD) using the same fabrication system. Poly-Si films with a strong 〈100〉 and 〈110〉 preferential orientation (P.O.) are obtained by changing the rf power for generating the plasma under the same preparation condition. The surface of the PECVD films with dominant 〈100〉 and 〈110〉 textures is very smooth in contrast with that of LPCVD films. These textures are maintained after thermal oxidation at 1000 °C, and the degree of P.O. and the grain size increase.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 406-408 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experimental results are presented for a nonreciprocal phase shift of vertically polarized waves in four-layer magneto-optic rib waveguides. The structure consists of a high refractive index nonmagnetic layer of titanium oxide on top of a magneto-optic film (a lanthanum and gallium substituted yttrium iron garnet film on a gadolinium gallium garnet substrate) to improve differential phase characteristics. The difference of phase constants for waves traveling in opposite directions is evaluated by observing the variation in the polarization coupled out of a straight waveguide when simultaneously exciting both horizontally and vertically polarized waves with equal amplitudes and phases. The phase shift difference varies with the thickness of the nonmagnetic film, and is larger than that of a previous three-layer waveguide in the overlayer thickness range 0.15–0.45 μm. The maximum phase shift obtained is 2.5 times as large as that of uncoated waveguides.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 339-341 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Fundamental characteristics of (111) oriented GaAs/AlGaAs graded-index separate-confinement-heterostructure single quantum well lasers have been compared with conventional (100) oriented lasers. In particular, the threshold current density Jth of (111) oriented lasers does not change with the well width Lz in the range of Lz=30–100 A(ring), which corresponds to an ideal extreme. The lowest Jth of 145 A/cm2 together with a high characteristic temperature T0 of 186 K in the threshold-temperature dependence has been achieved for an Lz of 40 A(ring) and a cavity length of 490 μm. The dependence of T0 on Lz showed that T0 is maximum at Lz∼60 A(ring) for both (111) and (100) oriented lasers.
    Type of Medium: Electronic Resource
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