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  • 82.50  (5)
  • Experimental allergic encephalomyelitis  (3)
  • GK rat  (3)
  • Ubiquitin  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 42 (1987), S. 167-172 
    ISSN: 1432-0649
    Keywords: 82.50 ; 82.40 ; 42.60.Kg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new working molecule 1,1,1,3,3,3-hexafluoro-2-(trifluoromethyl)-propane-2-t (CF3)3CT, is reported for the isotope separation of tritium by TEA CO2-laser-induced multiphoton dissociation (MPD). Selective and efficient dissociation of (CF3)3CT was observed by irradiation at about 980 cm−1 where (CF3)3CH was nearly transparent. The critical fluence for dissociation of (CF3)3CT at 10R(28) 980.9 cm−1 was estimated to be as low as 4.6 J/cm2, which is the lowest of the tritiated halocarbons that we have ever reported. A detailed study was made of the pressure dependence of the dissociation rate constants for (CF3)3CT and (CF3)3CH to clarify the collisional effects in their MPD. The hydrogen isotope exchange between (CF3)3CH and HTO was found to be extremely rapid, which is advantageous in the practical laser separation cycle for tritium removal from water.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0649
    Keywords: 07.75 ; 33.00 ; 82.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A MultiPhoton-Ionization Time-Of-Flight Mass Spectrometry (MPI/TOFMS) apparatus was developed for real-time measurement of the uranium isotopic ratio in nascent UF5 formed by the 266 nm photolysis of effusive UF6 ( 〈 300 K, ≈ 1.3 × 10−4 Pa). The UF5 was selectively and efficiently multiphoton ionized by 532 nm radiation at appreciably low fluences ( 〈 10 J/cm2). The main ions observed, U+ and U2+, were subsequently analyzed with a TOFMS with mass resolution of 1190 to separate235U n+ and238U n+ completely. The isotopic ratio measurements showed good precision resulting from the excellent agreement which was observed between the isotopic ratios in UF5 products and those in a parent UF6 sample. These results suggested that the MPI/TOFMS method can be applied to the real-time analysis of separation factors in the molecular laser isotope separation of uranium by ionization of UF5 following the infrared photodissociation of UF6.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0649
    Keywords: 82.50 ; 82.40 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Isotope separation of tritium from deuterium in heavy water was attempted by CO2-laser-induced, highly-selective multiphoton dissociation of C2TF5 present in C2DF5. Single-step T/D separation factors exceeding 3000, 1000, and 500 were attained, respectively, for the first time with CO2 laser 10P(34) 931.0 cm−1 at 10, 20, and 30 Torr pentafluoroethane pressures at −78 °C (i.e., equivalent to 15, 30, and 45 Torr at room temperature).
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 28 (1982), S. 341-348 
    ISSN: 1432-0649
    Keywords: 82.50 ; 82.40 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Isotope separation of tritium by CO2 laser-induced multiphoton dissociation (MPD) of C2TF5 is reported for the first time. The MPD spectrum obtained for C2TF5 comprised a broad peak at about 940 cm−1 where C2HF5 was nearly transparent. The unimolecular dissociation of C2TF5 was induced with much lower laser fluence than that for CTF3, another working molecule we proposed for laser isotope separation of tritium. The mechanisms and kinetics of the dissociation of C2TF5 and C2HF5 were investigated under various experimental conditions: laser frequency, pulse energy, pulse duration, tritium concentration, sample pressure, buffer gas pressure and irradiation geometry. Single-step separation factors exceeding 500 were achieved with the most efficientP(20) line in 00o–10o0 transition at 944.2 cm−1.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0649
    Keywords: 82.50 ; 33.00
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In infrared multiphoton dissociation of supercooled UF6 irradiated with multifrequency para-H2 Raman laser beams, separation factors and contrast ratios were measured by selective multiphoton ionization of the photoproduct UF5 at 532 nm followed by time-of-flight mass spectrometric analysis. The relationship between separation factor and contrast ratio is discussed theoretically and quantitatively investigated in the experiments. From this relationship, we obtain the irradiation conditions of the laser-beam fluences for attaining a high separation factor and estimate the value of the intrinsic separation factor in multifrequency dissociation of UF6.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0533
    Keywords: Olivopontocerebellar atrophy ; Oligodendroglia ; Argyrophilic inclusion ; Ubiquitin ; Leu-7
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We described cytoplasmic inclusions in glial cells in 18 patients with olivopontocerebellar atrophy (OPCA) (multiple system atrophy, MSA). These glial inclusions showed intense argyrophilia with modified Bielschowsky's and Bodian's silver impregnation techniques, and were observed in the pons, cerebellar white matter, midbrain, medulla oblongata and basal ganglia, as well as cerebral white matter and spinal cord. None of the 54 control cases had glial argyrophilic inclusions. Immunohistochemically, these inclusions were intensely labeled by anti-ubiquitin antibody. Some of them reacted with an antibody to Rosenthal fiber (RF) protein. The cytoplasm of ubiquitinated inclusion-bearing glial cells was immunostained by anti-Leu-7 antibody, but not by anti-GFAP antibody. Ultrastructurally, the glial inclusions were composed primarily of approximately 24- to 40-nm fibrils, which were coated with osmiophilic granular material along their length in longitudinal section. These fibrils appeared as annuli in cross section. Often, a central granule approximately 5 nm in diameter was seen in the lucent lumen of a cross-sectioned fibril. The granule-coated fibrils were not seen in the glial filament-containing astrocytes. Electron microscopic examination of silver-impregnated specimens revealed that the granule-coated fibrils had strong affinity for silver. Immunoelectron microscopy using the indirect immunoperoxidase techniques with antibodies to ubiquitin and RF protein revealed that the electron-dense reaction products respective to both were located on constituents of glial inclusions. Our observation that Leu-7-positive glial cells, mainly oligodendroglial cells, had argyrophilic ubiquitinated inclusions may be of significance for the evaluation of the pathology of OPCA(MSA).
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0533
    Keywords: Olivopontocerbellar atrophy ; Argyrophilic inclusion ; Pontine nucleus ; Ubiquitin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Patients with olivopontocerebellar atrophy (OPCA) were studied, and cytoplasmic inclusions were observed in some of the remaining neurons of the pontine nuclei, nuclei reticularis tegmenti pontis and arcuate nuclei. The cytoplasmic argyrophilic inclusions were demonstrated by silver impregnation techniques such as Bielschowsky and Bodian staining. With hematoxylin and eosin stain, the inclusions were sharply demarcated and appeared pale. The inclusions were not stained by the following routine histological methods: Klüver-Barrera, phosphotungstic acid hematoxylin, Holzer, periodic acid-Schiff, Mallory azan, alcian blue, nile blue, Masson trichrome, Congo red, thioflavine S, oil red O and Sudan black B stains. Immunohistochemistry with anti-ubiquitin antiserum showed that these inclusions were ubiquitinated. However, the inclusions did not react with any of the following antibodies (Abs) or antisera: anti-phosphorylated neurofilament (NF) Ab, anti-nonphosphorylated NF Abs (160 and 200 kDa), anti-paired helical filament antiserum, anti-tau antiserum, anti-tubulin Abs (alpha and beta), anti-microtubule-associated proteins antiserum, anti-glial fibrillary acidic protein antiserum, anti-vimentin Ab, anti-desmin Ab, anti-cytokeratin Abs (low and high molecular weights), anti-actin antiserum, anti-skeletal myosin antiserum and anti-myelin basic protein Ab. Ultrastructurally, the inclusion bodies noted in OPCA were composed primarily of fibrils having a width ranging from about 24 to 40 nm, which were entirely coated with osmiophilic granular material along their whole length. They were occasionally intermingled with a few filaments about 10 nm in width. Electron microscopical examination on silver-impregnated specimens revealed that each granule-coated fibril had a great affinity for silver particles. In elucidating the pathogenesis of OPCA, it was considered to be an important neuropathological finding that some of the remaining pontine neurons affected by OPCA developed characteristic cytoplasmic argyrophilic inclusions.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0533
    Keywords: Alkaline phosphatase ; Blood-brainbarrier ; Cytochemistry ; Endothelial cell ; Experimental allergic encephalomyelitis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To investigate the functions of endothelial cell (ECs) in chronic relapsing experimental allergic encephalomyelitis (EAE), we examined ECs ultracytochemically in various stages of EAE, in conjunction with the localization of alkaline phosphatase (AP) activity. We also studied the relation between the specific localization of AP activity and pathological features at each stage. Chronic relapsing EAE was induced in strain-13 guinea pigs by inoculation with homologous myelin. Controls were inoculated with complete Freund's adjuvant. The controls showed AP activity on the luminal and abluminal surfaces of the plasmalemma, and in pinocytic vesicles and vesicular pits. The localization of AP activity in the preclinical stage of EAE was similar to that in control animals. The initial inflammatory and actively demyelinating stage with perivascular cuffs of mononuclear cells showed AP-positive reactions on the abluminal surface of the plasmalemma, and in vesicles and pits, but not on the luminal surface in many ECs. In a later stage showing relatively old plaques with perivascular accumulation of debris-containing macrophages, AP activity continued to show localization similar to that seen in the initial stage, except for the presence of AP activity on some segments of the abluminal plasmalemma. Inactive lesions with marked perivascular fibrosis showed no AP reaction products. AP activity in unaffected areas showed the same localization as that in control animals throughout the various clinical stages of EAE. These findings suggest that AP activity decreased as the inflammatory demyelination in EAE progressed. The gradual disappearance of AP activity suggests development of functional impairment of ECs.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0533
    Keywords: Werdnig-Hoffmann disease ; Extraocular muscle nuclei ; Chromatolytic neuron ; Phosphory-lated neurofilament ; Ubiquitin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The extraocular muscle nuclei in one case of Werdnig-Hoffmann disease were examined immunocytochemically using antibodies against phosphorylated neurofilament (pNF) and ubiquitin (UBQ). The oculomotor and trochlear nuclei showed several chromatolytic ballooned neurons. All ballooned neurons contained epitopes of pNF and UBQ. pNF were present mainly in the periphery of the cell in a ring-like shape and were occasionally seen in the center of some cells. On the other hand, the structures stained by the antibody to UBQ were small vesicles or granules and most of them were aggregated in the center of the cell. These distribution patterns of pNF and UBQ may be unique in Werdnig-Hoffmann disease, since similar patterns were reported in other types of neurons of Werdnig-Hoffmann disease but were not seen in two other motor neuron diseases: classical amyotrophic lateral sclerosis, and familial amyotrophic lateral sclerosis with posterior column and spinocerebellar tract involvement.
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  • 10
    ISSN: 1432-0533
    Keywords: Experimental allergic encephalomyelitis ; Blood-brain barrier ; Na+, K+-Adenosine triphosphatase ; Basal lamina ; Horseradish peroxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We induced chronic relapsing experimental allergic encephalomyelitis (EAE), and studied the ultrastructural and ultracytochemical changes of the blood-brain barrier (BBB) in the demyelinating lesions of various stages of EAE. In the chronic, inactive stage with gliosis and perivascular fibrosis, the basal lamina (BL) of the perivascular processes of astrocytes was formed only partially, and neural parenchyma was not fully separated from the perivascular mesenchymal tissues by the BL of astrocytic processes. Vascular permeability of the BBB was studied using exogenous horseradish peroxidase (HRP) as the tracer: HRP extravasation was marked during the stages of both active myelin breakdown and removal of debris, and was recognized even at the inactive stage, although the degree was reduced to a very low level. The functions of the endothelia, assessed by ouabain-sensitive, K+-dependentp-nitrophenylphosphatase activity, were impaired as EAE progressed. The decrease in HRP leakage at the inactive stage suggests the endothelial impairment of active transport of metabolites including HRP. Along with the development of infammatory demyelination in EAE, the BBB in affected areas became more and more altered, and gradual morphological and functional impairment of the BBB developed.
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