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  • 1
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 3421-3423 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We investigated Si-doped GaN epitaxial layers on a (0001)-sapphire substrate using a HCl vapor-phase etching technique, scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. Three kinds of distinctive etch pits correspond to three different types of threading dislocations, edge, mixed, and screw types. Photoluminescence intensity increases with the decrease in the number of etch pits corresponding to mixed and screw dislocations. The number of etch pits corresponding to edge dislocations, however, did not change. We concluded, therefore, that threading dislocations having a screw-component burgers vector act as strong nonradiative centers in GaN epitaxial layers, whereas edge dislocations, which are the majority, do not act as nonradiative centers. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
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  • 2
    ISSN: 1398-9995
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Conclusions: These results indicated that TNF-α-induced p38 MAP kinase activation and p38 MAP kinase-mediated RANTES production by human pulmonary vascular endothelial cells are inversely regulated by intracellular GSH levels.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1399-3054
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Water (H2 15O) translocation from the roots to the top of rice plants (Oryza saliva L. cv. Nipponbare) was visualized over time by a positron-emitting tracer imaging system (PETIS). H2 15O flow was activated 8 min after plants were exposed to bright light (1 500 μmol m−2 s−1). When the light was subsequently removed, the flow gradually slowed and completely stopped after 12 min. In plants exposed to low light (500 μmol m−2 s−1), H2 15O flow was activated more slowly, and a higher translocation rate of H2 15O was observed in the same low light at the end of the next dark period. NaCl (80 mM) and methylmercury (1 mM) directly suppressed absorption of H2 15O by the roots, while methionine sulfoximine (1 mM), abscisic acid (10 μM) and carbonyl cyanide m-chlorophenylhydrazone (10 mM) were transported to the leaves and enhanced stomatal closure, reducing H2 15O translocation.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1365-2222
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: RANTES plays an important role in the production of allergic inflammation of the airway through its chemotactic activity for eosinophils. The cellular reduction and oxidation (redox) changes are involved in the activation of p38 mitogen-activated protein (MAP) kinase and the induction of cytokine expression. It has previously been shown that tumour necrosis factor (TNF)-MA activates p38 mitogen-activated protein (MAP) kinase to produce cytokine, including RANTES, that N-acetylcysteine (NAC) attenuates cytokine production by human bronchial epithelial cells (BECs), and that sensitivity to TNFα is inversely correlated with cellular redox state. However, a role of cellular redox regulated by intracellular glutathione (GSH) in TNFα-induced p38 MAP kinase activation and p38 MAP kinase-mediated RANTES production by human BECs has not been determined.Human BECs were exposed to NAC or buthionine sulfoximine (BSO). TNFα-induced p38 MAP kinase activation and p38 MAP kinase-mediated RANTES production by human BECs were then examined in order to clarify these issues.The results showed that: NAC attenuated TNFα-induced p38 MAP kinase activation and RANTES production; SB 203580 as the specific inhibitor of p38 MAP kinase activity attenuated TNF-α-induced RANTES production; BSO facilitated TNF-α-induced p38 MAP kinase activation and RANTES production; SB 203580 attenuated BSO-mediated facilitation of TNF-α-induced RANTES production; and the intracellular GSH increased in NAC-treated cells, whereas the intracellular GSH was reduced in BSO-treated cells.These results indicate that cellular redox regulated by GSH is critical for TNF-α-induced p38 MAP kinase activation and p38 MAP kinase-mediated RANTES production by human BECs.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1365-2222
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background Influenza virus (IV) infection causes airway inflammation; however, it has not been determined whether IV infection could catabolize arachidonic acid cascade in airway epithelial cells. In addition, the responsible intracellular signalling molecules that catabolize arachidonic acid cascade have not been determined.Objective In the present study, to clarify these issues, we examined the cyclooxygenase (COX) expression, cytosolic phospholipase A2 (cPLA2) phosphorylation and prostaglandin E2 (PGE2) release in human bronchial epithelial cells (BEC) upon IV infection, and the role of mitogen-activated protein kinase (MAPK) including extracellular signal-regulated kinase (ERK), p38 MAPK and c-Jun-NH2-terminal kinase (JNK) in catabolizing arachidonic acid cascade in BEC.Methods COX-2 expression, phosphorylation of cPLA2 and phosphorylation of ERK, JNK and p38 MAPK were determined by Western blot. The concentrations of PGE2 were determined by ELISA. PD 98059 as a specific inhibitor of MAPK kinase-1 (MEK-1), an up-stream kinase of ERK, SB 203580 as a specific inhibitor of p38 MAPK and CEP-11004 as a specific inhibitor of JNK cascade were used to investigate the role of ERK, p38 MAPK and JNK in catabolizing arachidonic acid cascade in BEC.Results The results showed that (1) IV infection increases COX-2 expression, cPLA2 phosphorylation and PGE2 release, (2) ERK, p38 MAPK and JNK were phosphorylated, (3) CEP-11004 and PD 98059 predominantly attenuated COX-2 expression and cPLA2 phosphorylation, respectively, (4) SB 203580 did not remarkably affect COX-2 expression and cPLA2 phosphorylation, and (5) each inhibitor dose-dependently attenuated PGE2 release by various extents.Conclusion These results indicate that IV infection activates three distinct MAPKs, ERK, p38 MAPK and JNK, to participate to various extents in the induction of PGE2 synthesis from arachidonic acid in BEC.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    Clinical and experimental dermatology 25 (2000), S. 0 
    ISSN: 1365-2230
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Chemotherapy-induced acral erythema (CAE) is an uncommon and distinct reaction seen in patients receiving high-dose chemotherapy. The exact pathogenic mechanisms of this disorder are still unknown. We report a 27-year-old woman who presented with red, swollen and painful macules on both palms, clinically consistent with this disease. Histological examination demonstrated vacuolar degeneration of the basal cell layer and spongiotic blisters in the epidermis, especially in the atrophied eccrine ducts and papillary oedema with mild perivascular infiltration of mononuclear and hypersegmented neutrophils. Immunohistochemistry showed that the infiltrating mononuclear cells were CD3–CD16+CD56+ leucocyte function antigen-1+, possibly natural killer cells. The eccrine ducts expressed HLA-DR and intracellular adhesion molecule-1 (ICAM-1). Our findings suggest that cell-to-cell interaction between NK cells and keratinocytes in the eccrine apparatus may induce CAE and may be involved in the pathogenesis of the skin reaction in our patient and possibly in this disease.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Oxford, UK : Munksgaard International Publishers
    Journal of periodontal research 39 (2004), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Background and objective:  It is still an open question why long junctional epithelium can proliferate and occupies the root surface following periodontal surgery or experimentally produced periodontitis, and why the epithelium repopulated once on the root surface is replaced by the connective tissue. The aim of this study is to investigate the proliferative activity of the newly formed regenerative connective tissue and long junctional epithelium during wound healing by staining argyrophilic proteins of the nucleolar organizer regions (AgNORs).Methods:  Regenerative connective tissue and long junctional epithelium were experimentally created by insertion of a rubber piece between maxillary molars of rats for 1 week. After removal of the rubber, AgNORs parameters including nuclear area (NA), AgNORs area (AA), AgNORs percentage nuclear area (APNA), AgNORs number (AN) and nuclear number (NN) in regenerative connective tissue and long junctional epithelium were measured and analyzed statistically.Results:  APNA in long junctional epithelium after 1 and 4 weeks was over two times greater than that in the regenerative connective tissue. AA in long junctional epithelium was significantly higher than in regenerative connective tissue at 1 and at 4 weeks post-treatment. AN was higher in the central portion than at the root surface except at 20 weeks. APNA and AA decreased remarkably in long junctional epithelium at 12 weeks post-treatment (approximately half at 4 weeks), whereas in regenerative connective tissue, they did not change distinctly.Conclusions:  These results imply that long junctional epithelium cannot supply sufficient epithelial cells because of their significantly low rates of proliferation, consequently long junctional epithelium becomes shorter after 12 weeks, whereas the proliferative activity of regenerative connective tissue maintains the same level of proliferation, and ultimately long junctional epithelium is replaced by regenerative connective tissue.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 7 (1974), S. 67-73 
    ISSN: 1600-5767
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Geologie und Paläontologie , Physik
    Notizen: The structure of the interstitially ordered lattice formed in zirconium–oxygen alloys has been studied with use of single-crystal data obtained by X-ray and neutron diffraction methods. The structure belongs to space group P312 and the lattice parameters a and c are related to a0 and c0 of the host hexagonal metal lattice by a = √3a0 and c = c0. The ordered arrangement of interstitial oxygen atoms is described as a regular stacking of layers parallel to the (00.1) plane with the sequence (AC)B(AC)B... which is of the same type as that of nitrogen atoms in ε-Fe2N. The occupancy probability of oxygen atoms is high for interstitial sites of the A and B types while it is low for sites of the C type. The host metal lattice is distorted in such a way that spacings of successive (00.2) planes are not the same and a hexagonal network of atoms in these planes is periodically deformed.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 30 (1974), S. 792-798 
    ISSN: 1600-5724
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Notizen: A diffraction theory is developed for diffuse scattering from disordered binary alloys with short-range order. It is based on a model of ordered microdomains embedded in a disordered matrix and interference effects between the domains are considered. There is a possibility that the fine structures of diffuse scattering as observed in the cases of Cu3Au, CuAu and Cu3Pd alloys result from the introduction of interdomain correlations. From experimental diffuse intensity values one can calculate the statistical distribution of microdomains in antiphase with one another.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1420-908X
    Schlagwort(e): Key words: Aceclofenac — 4′-Hydroxy aceclofenac — Pro-matrix metalloproteinase 1 — Pro-matrix metalloproteinase 3 — Rheumatoid synovial cell
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. Objective and Design: We examined the effects of aceclofenac and its metabolites on the production of pro-collagenase-1/pro-matrix metalloproteinase-1 (proMMP-1), pro-gelatinase A/proMMP-2, pro-stromelysin-1/proMMP-3 and tissue inhibitor of metalloproteinases-1 (TIMP-1) by rheumatoid synovial cells.¶Materials: Synovial cells were obtained from patients with rheumatoid arthritis.¶Treatment: Cultures of confluent cells were treated with interleukin-1β (IL-1β)(1 ng/ml) and/or test drugs (0.3-30 μM) for 48 h.¶Methods: Production of proMMPs and TIMP-1 was monitored by Western blotting or gelatin zymography. Prostaglandin E2 (PGE2) was measured by an enzyme immunoassay.¶Results: 4′-Hydroxy aceclofenac, a major metabolite of aceclofenac, down-regulated both basal and IL-1β-induced production of proMMP-1 and proMMP-3 at a concentration sufficient to suppress PGE2 production without modulating proMMP-2 or TIMP-1, whereas aceclofenac itself had no marked effect on the production of proMMPs.¶Conclusions: Down-regulation of proMMP-1 and proMMP-3 production by 4′-hydroxy aceclofenac may contribute to the therapeutic effect of aceclofenac on rheumatoid arthritis and osteoarthritis.
    Materialart: Digitale Medien
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