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  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 5632-5634 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have found a new electron trap state in Si-doped AlxGa1−xAs by deep level transient spectroscopy and constant temperature capacitance transient measurements under strong light illumination. This new trap is shallower than the DX center associated with Si impurity in that its emission and capture activation energies are equal to 0.20±0.05 and 0.17±0.05 eV, respectively. Its maximum concentration is comparable to the concentration of the DX center. Possible origins of this new trap and its relationship to the DX center are discussed.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 51 (1987), S. 349-351 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Deep centers induced by hydrostatic pressure in GaAs:Si have been studied by deep level transient spectroscopy and constant temperature capacitance transient techniques. The capture behavior of these centers has been studied in detail and found to be consistent with the multiphonon emission theory. The pressure coefficients of the ionization energy and the barrier height are consistent with the large lattice relaxation model proposed by D. V. Lang and R. A. Logan [Phys. Rev. Lett. 39, 635 (1977)].
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 1195-1197 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The pressure dependence of the DX center in Ga1−xAlxAs :Te has been studied in two samples with x=0.15 and 0.35, respectively. The pressure coefficients of the activation energies for both emission and capture were found to change sign when the band gap of GaAlAs changes from direct to indirect. These results, together with previous experiments, suggested that electrons can be emitted from and capture into the DX centers via both L and X valleys.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 1344-1346 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We found that, when boron was introduced into GaAs:Si, the deep donors induced by pressure exceeding 20 kbar reported previously by M. Mizuta, M. Tachikawa, H. Kukimoto, and S. Minomura [J. Appl. Phys. 24, L143 (1985)] disappeared while new donor levels with reduced binding energies and capture barrier heights appeared. It is proposed that B atoms paired up with Si donor atoms and the resultant change in the short-range potential of the Si donor atoms depressed the capture barrier height of the pressure-induced deep donor.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 974-976 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The Schottky barrier height at the Pt/GaAs interface has been measured as a function of pressure using a diamond anvil cell. The Schottky barrier height was found to shift to higher energy with a linear pressure coefficient of 11 meV/kbar, which is equal to the pressure coefficient of the fundamental gap of GaAs and with a nonlinear coefficient of −0.26 meV/kbar2. These results are discussed in terms of defect models which have been proposed to explain the Fermi level pinning in Schottky barriers.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish diseases 11 (1988), S. 0 
    ISSN: 1365-2761
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
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  • 7
    ISSN: 1365-2133
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background  Punctate palmoplantar keratoderma (PPK) is a rare autosomal dominant cutaneous disorder characterized by numerous hyperkeratotic papules distributed on the palms and soles. Two loci for punctate PPK were recently found to be located on 8q24.13–8q24.21 and 15q22–15q24. However, no genes for this disease have been identified to date.Objectives  To refine the previously mapped regions and to identify the disease gene locus in a four-generation Chinese family with punctate PPK.Methods  Genetic linkage analysis was carried out in this family using microsatellite markers on chromosomes 8q and 15q. Two-point linkage analysis was performed using Linkage programs version 5·10 and the haplotype was constructed using Cyrillic version 2·02 software.Results  We failed to confirm our previous locus at 8q24.13–8q24.21, but significant evidence for linkage was observed in the region of 15q with a maximum two-point LOD score of 5·38 at D15S153 (θ = 0·00). Haplotype analysis localized the punctate PPK locus within the region defined by D15S651 and D15S988. This region overlaps by 5·06 cM with the previously reported punctate PPK region.Conclusions  This study refines a disease gene causing punctate PPK to a 5·06-cM interval at 15q22.2–15q22.31.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 21 (2005), S. 0 
    ISSN: 1460-9568
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The present study focuses on the nicotine-induced modulation of mRNA and protein expression of a number of genes involved in glutamatergic synaptic transmission in rat brain over different time periods of exposure. A subchronic (3 days) but not the chronic (7 or 14 days) administration of nicotine resulted in the up-regulation of Homer2a/b mRNA in the amygdala while in the ventral tegmental area (VTA) no change in expression of either Homer2a/b or Homer1b/c was observed. Although the increase in Homer2a/b mRNA was not translated into the protein level in the amygdala, a slight but significant up-regulation of Homer1b/c protein was observed in the same region at day 3. Both Homer forms were up-regulated at the protein level in the VTA at day 3. In the nucleus accumbens, 14 days of nicotine treatment up-regulated mRNA of Homer2b/c by 68.2% (P 〈 0.05), while the short form Homer1a gene was down-regulated by 65.0% at day 3 (P 〈 0.05). In regard to other components of the glutamatergic signalling, we identified an acute and intermittent increase in the mRNA and protein levels of mGluR1 and mGluR5 in the amygdala. In the VTA, however, the effects of nicotine on mGluR mRNA expression were long-lasting but rather specific to mGluR1. Nevertheless, mGluR1 protein levels in the VTA area were up-regulated only at day 3, as in the amygdala. These data provide further evidence for the involvement of nicotine in the glutamatergic neuronal synaptic activity in vivo, suggesting a role for the newly identified Homer proteins in this paradigm.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    Clinical and experimental dermatology 30 (2005), S. 0 
    ISSN: 1365-2230
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Very few articles have aimed to illuminate the clinical profiles of vitiligo in China. We conducted this retrospective survey involving 4118 outpatients with vitiligo in order to identify the differences among various clinical types of vitiligo and their associated disorders. Completed questionnaires (3742) were validated and analysed. Of this large cohort, 1565 (41.8%) individuals presented vitiligo vulgaris, followed by focal, segmental, acrofacial, and universal, in that order. The mean age of vitiligo onset was 18.88 years. More than 60% of the patients were affected before 20 years of age. Patients with segmental vitiligo were affected earlier than those with other types of vitiligo (15.55 years; (P 〈 0.001). More than 74% of the patients presented with focal vitiligo at onset. After 3–5 years, 99% of active vitiligo was worse and shifted from one clinical type to another. However, there was no transformation between acrofacial vitiligo and segmental vitiligo. Compared with the general population, the patients with vitiligo were more likely to be affected by rheumatoid arthritis (P 〈 0.01), ichthyosis (P 〈 0.01), chronic urticaria (P 〈 0.01), or alopecia areata (P 〈 0.01).
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Oxford, UK : Munksgaard International Publishers
    Allergy 60 (2005), S. 0 
    ISSN: 1398-9995
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background:  Prominent infiltration of eosinophils into the airway mucosa and release of inflammatory mediators upon their adhesion onto airway epithelial cells are the immunopathogical mechanisms of allergic asthma.Objective:  We investigated the effect of normal and paraformaldyhyde-fixed human eosinophils on BEAS-2B cells, a human bronchial epithelial cell line, for the release of inflammatory cytokine interleukin (IL)-6.Methods:  Interleukin-6 in cell culture supernatant, protein amount of p38 mitogen-activated protein kinase (MAPK), and nuclear factor-κB (NF-κB) activity in BEAS-2B cells were analyzed by Western blot and enzyme-linked immunosorbent assay (ELISA). IL-6 gene expression was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR), and p38 MAPK activity and inhibitor (I)κB-α induction were evaluated by Western blot.Results:  Co-culture of BEAS-2B cells and eosinophils induced a significant elevation of IL-6 expression in BEAS-2B cells. Interaction of eosinophils and BEAS-2B cells led to a marked induction in phospho-p38 MAPK, phospho-IκB-α and activity of NF-κB in BEAS-2B cells. NF-κB inhibitor BAY 11-7082 and p38 MAPK inhibitor SB 203580 significantly decreased IL-6 release in a co-culture of BEAS-2B cells and eosinophils. Fixed human eosinophils were able to maintain their ability to induce IL-6 release in co-culture, activate p38 MAPK and NK-κB, and up-regulate IL-6 gene expression in BEAS-2B cells.Conclusions:  These data indicate that the interaction of eosinophils and bronchial epithelial cells plays an important role in airway inflammation, at least partly, via IL-6 induction.
    Materialart: Digitale Medien
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