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  • 1
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The effect of thermal-diffusion charge on the x-ray energy response of silicon surface-barrier (SSB) detectors have generally been ignored; consequently, the SSB response has been believed to be analyzed using the thickness of the depletion layer alone. Our new theory on the SSB x-ray response [J. Appl. Phys. 72, 3363 (1992)] was prepared for addressing recent confusion on plasma x-ray analyses using SSB detectors [Rev. Sci. Instrum. 59, 1380 (1988); 61, 693 (1990); 63, 4850 (1992)]. This approach was made under the assumption of a dominant contribution of the diffusion-charge signal in the vicinity of the x-ray incident location because of the strong reduction of the x-ray produced charge within the thermal-diffusion length. In this report, the comparison between this approximation (having an approximated solution) and the exact numerical calculation (using an integral form) is carried out. Necessity and importance of such three-dimensional treatments for the data analyses as well as the design of multichannel semiconductor-array detectors developed for plasma x-ray tomography diagnostics are highlighted. Furthermore, for the total diffusing-charge amount, the calculated results from our theory and the values using the comment from Donolato agree well within the accuracy of 1%.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: An analytical method based on a new theoretical model for the x-ray energy responses of silicon surface-barrier (SSB) detectors has been proposed. This method may address a recent confusing issue in the x-ray detection characteristics of SSB semiconductor detectors; that is, the x-ray responses of SSB detectors as well as p-i-n diodes used in underbiased operations were recently found to be contrary to the commonly held belief that the x-ray sensitivity of an SSB detector is determined by the thickness of the depletion layer. The model presented includes a signal contribution from thermally diffusing charge that is created in the field-free substrate region within a diffusion length from the depletion layer along with a signal contribution from charge created in the depletion layer. This model predicts a large signal contribution from the charge-diffusion effect on the SSB responses to high-energy x rays. Formulas and calculated results supporting SSB calibration data have been represented. These analytical methods might be developed to apply the analyses and predictions of energy responses of various types of silicon detectors including p-i-n diodes as well as charge-coupled devices.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 1694-1699 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Tomographic reconstructions of x-ray emission from hot electrons have been carried out in the thermal barrier region of the GAMMA 10 plasmas. Here, the first application of two sets of the 50-channel microchannel plates have been performed using their detailed calibration data as a function of x-ray energy and incident angle [Rev. Sci. Instrum. 59, 256 (1988); 59, 2453 (1988); 60, 368 (1989)]. The x-ray reconstructed signals under standard thermal barrier operating conditions indicate a good axisymmetric radial profile peaked on the magnetic axis. This symmetric profile is important for preventing the formation of a local anisotropic electric field, which may cause particle confinement degradation, and its peaking profile is desirable for thermal barrier potential formation in the core plasma region. When we have relocated the second-harmonic electron cyclotron layers (ω=2Ωe) in two different ways (moving them out radially, or axially away from the midplane), tomographic reconstructions show hollow x-ray profiles in both cases. These may be formed due to the E×B rotations of the hot electrons produced near ω=2Ωe . These applications of x-ray tomography to two-dimensional radial profile observations along with the axial x-ray profile measurement give information that the production mechanism of these hot electrons is ascribed to second-harmonic electron cyclotron heating.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 2566-2570 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The characteristics of microchannel plates (MCPs) for x-ray detection have been investigated with continuous x-ray energy variation using synchrotron radiation in the XUV and soft x-ray region (from 60 to 600 eV). The current response data have shown x-ray absorption fine structure (EXAFS or XANES) near the oxygen K absorption edge as well as a jump structure near the silicon L edge; these structures are explained by the surface composition of channel walls (SiO2). The data show that the surface layer of a microchannel is essential for x-ray detection by MCPs in this energy range. The precise current response curve has been completed for the wide x-ray energy range from 0.06 to 82 keV combined with the previously reported data [Kondoh et al., Rev. Sci. Instrum. 59, 252 (1988); Cho et al., ibid. 59, 2453 (1988); Yamaguchi et al., ibid. 60, 368, 2307 (1989)].
    Materialart: Digitale Medien
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  • 5
    ISSN: 1432-8798
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A region of the human cytomegalovirus genome (corresponding to nt 17973-19945 of strain AD169) was analyzed by restriction fragment length polymorphism. Rsa I digestion of the region showed 20 distinct patterns in agarose gel electrophoresis.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1432-0533
    Schlagwort(e): Membranous lipodystrophy ; Thalamic degeneration ; Neuropathology ; Autopsy ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An autopsied case of membranous lipodystrophy (Nasu-Hakola disease, NHD) with thalamic degeneration was reported. A 34-year-old Japanese man was diagnosed as having NHD by bone biopsy prior to the onset of clinical symptoms. His maternal grandfather and paternal grandmother are cousins, but this family history is negative for NHD. He developed frontal lobe syndrome at the age of 35 with progressive dementia, and died of acute renal failure at the age of 46. Gross inspection of the brain detected atrophy and softening of the cerebral white matter, predominantly in the frontal lobe. Microscopically, numerous spheroids, predominant fibrillary gliosis with less prominent demyelination “dissociation glio-myélinique” and scanty sudanophilic lipid droplets were observed, indicating the sclerosing type of NHD. An unusual pathological finding in this case was selective involvement of the thalamic nuclei with preservation of the other gray matter except for focal cortical necrosis. The topography of the affected thalamic nuclei is similar to that of systemic thalamus degeneration. An association with thalamic degeneration in NHD has not been previously reported. The present case suggests that NHD also affects the thalamus.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 46 (1994), S. 367-369 
    ISSN: 1432-1041
    Schlagwort(e): Clotiazepam ; Schizophrenia ; benzodiazepine derivative ; auditory hallucinations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Abstract We report that high doses of the benzodiazepine derivative, clotiazepam, given in addition to standard neuroleptics often exert a minor beneficial effect on long-lasting, neuroleptic resistant auditory hallucinations in chronic schizophrenic patients of the residual type.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1432-0584
    Schlagwort(e): Extramedullary tumor ; Malignant lymphoma ; Granulocytic sarcoma ; GPIIb- and GPIIIa-positive leukemia cell line
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A 25-year-old man noted swelling of the right cervical lymph nodes in October 1983. Diagnosis of malignant lymphoma was made on the basis of pathological examination of biopsies. Despite both chemotherapy and irradiation treatment, blast cells appeared in the peripheral blood and bone marrow in April 1984. Immunophenotypic analysis demonstrated that the blasts in the patient's peripheral blood expressed CD13, CD33, CD41a, and no markers for T or B lymphocytes, suggesting that he had been suffering from megakaryocytic sarcoma. We established a new cell line derived from the blasts in the peripheral blood, designated KH184. KH184 cells expressed glycoprotein (GP) Ib (CD42b) and GPIIb/IIIa (CD41a), while platelet peroxidase (PPO) activity was negative in an ultrastructural study. Both Northern blot and flow cytometric analysis of surface antigens and DNA content revealed that treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) did not induce the maturation of these cells. Various cytokines such as interleukin 3 (IL-3), interleukin 6 (IL-6), and leukemia inhibitory factor (LIF) had no effect in promoting the growth of KH184 cells. KH184 cells expressing CD41a seem to possess unusual characteristics. KH184 cells, human GPIIb- and GPIIIa-positive leukemia cells, which lack response to TPA-induced differentiaton, provide a new and unique model for the characterization of factors that are implicated in the terminal differentiation of megakaryocytes, and should aid in studies of the mechanism underlying the occurrence of megakaryocytic sarcoma.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Neocortex ; GABA ; Kindling ; Rabbits
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary To investigate how GABAergic function affects seizure development, the effects of a GABA antagonist, bicuculline, on neocortical and hippocampal kindling were examined in chronically prepared rabbits. Kindling-inducing stimulations consisted of stimulus trains repeated at 5-min interstimulus intervals to produce so-called “rapid kindling”. The changes in after-discharge (AD) durations induced by each of 15 trials of stimulus trains per session were compared before and 30 min after i.p. injection of bicuculline solution (2 mg/kg) in each of three kindling groups consisting of 5 rabbits each, i.e. visual cortical, motor cortical and hippocampal kindling groups. In the visual cortex and to a less extent, the motor cortex kindling groups, the AD durations were shortened after bicuculline injection and did not show the progressive prolongation seen before the injection. In contrast, the hippocampal kindling group showed a further marked prolongation of the AD durations after the injection. The bicuculline-induced blockade of neocortical kindling suggests facilitative GABAergic action on seizure development, while the drug-induced enhancement of hippocampal kindling reflects the known inhibitory GABAergic action.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurology 237 (1990), S. 372-375 
    ISSN: 1432-1459
    Schlagwort(e): Epilepsy ; Single photon emission computed tomography ; N-Isopropyl-(iodine 123) p-iodoamphetamine ; Regional cerebral blood flow
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Single photon emission computed tomography (SPECT) brain scans with N-isopropyl-(iodine 123) p-iodoamphetamine (123I-IMP) were performed three times in interictal periods in a 35-year-old man with intractable frontal lobe epilepsy and normal X-ray CT findings. The first scan showed decreased 123I-IMP uptake in the right frontal lobe. This abnormal image was regarded as the primary focus of his epilepsy on the basis of its regional agreement with focal epileptic discharges on EEGs. In the second scan, he showed normal imaging, while the third scan showed the same abnormal image as before, in the right frontal lobe. The frequency of his clinical seizures was almost unchanged during the intervals between scans and further EEGs recorded soon after each scan showed almost no changes in the basic activities and frequency of the epileptic discharges. Such fluctuations in SPECT brain imaging suggest that the severity of functional inactivation underlying the focal hypoperfusion image as an epileptic focus may fluctuate considerably in the interictal state with no relation to the clinical features of epilepsy.
    Materialart: Digitale Medien
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