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  • Electronic Resource  (21)
  • 1995-1999  (21)
  • 1999  (15)
  • 1995  (6)
  • 1
    Electronic Resource
    Electronic Resource
    Upconversion mechanism in Er3+-doped fluorozirconate glasses under 800 nm excitation (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 29-37 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The upconversion emission intensities of Er3+ ion around 550 and 660 nm in fluorozirconate glasses were measured under 800 nm excitation. Though energy transfer processes played an important role in upconversion mechanism at high concentration of ErF3, those have not been treated quantitatively. The energy transfer rates were calculated from the optical parameters assuming some distribution of Er3+ ions. We calculated the upconversion intensities around 550 and 660 nm by using rate equations. It was found that the dependence of upconversion emission intensities on the ErF3 concentration could be reproducible and the principal upconversion mechanism could be evaluated. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.369445
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of Yb3+ doping on upconversion emission intensity and mechanism in Er3+/Yb3+-codoped fluorozirconate glasses under 800 nm excitation (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 6143-6149 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Er3+ singly- and Er3+/Yb3+-codoped fluorozirconate glasses were prepared. The upconversion emission intensities of the Er3+ ion around both 550 and 660 nm were measured under 800 nm excitation. The absorption band of the Yb3+ ion is located around 980 nm. Though the absorption band of Yb3+ does not interact directly with the incident light at 800 nm, both upconversion intensities around 550 and 660 nm emission increased with the increasing YbF3 concentration. We calculated the upconversion intensities around 550 and 660 nm by using rate equations and evaluated the principal upconversion mechanism in Er3+ singly- and Er3+/Yb3+-codoped samples quantitatively. We also investigated the reason for the increase of the upconversion emission intensities with the codoping of Yb3+ under 800 nm excitation. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371666
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  • 3
    Electronic Resource
    Electronic Resource
    Electromyographic study of the activity of jaw depressor muscles before initiation of opening movements (1999)
    Oxford, UK : Blackwell Science Ltd
    Journal of oral rehabilitation 26 (1999), S. 0 
    Details
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The authors attempted to clarify the primary factors affecting the timing of the initial electromyographic discharges in the jaw depressor muscles (EMG onset). The changes in EMG onset in the inferior head of the lateral pterygoid (Lpt) and the anterior belly of the digastric muscles (Dig) were measured by varying duration of the open–close movement or occlusal force during the open–close–clench cycle (OCC). EMG onset tended to precede the beginning of the opening movement during OCC. The duration of opening and closing phase and the duration of occluding phase showed no significant correlation with the time-lag between EMG onset and the beginning of the opening movement (onset time).The mean EMG activity of the masseter muscle (Mm), corresponding to the occlusal force, showed a highly significant correlation with the onset time. The maximal opening velocity was highly correlated with the mean EMG activity of the jaw depressors before jaw opening. In conclusion, it was found that occlusal force is a major factor in EMG onset in the jaw depressors. It is suggested that smooth opening needs tooth contact with some degree of occlusal force.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2842.1999.00401.x
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  • 4
    Electronic Resource
    Electronic Resource
    Gravitationally redshifted emission implying an accretion disk and massive black hole in the active galaxy MCG63015 (1995)
    [s.l.] : Nature Publishing Group
    Nature 375 (1995), S. 659-661 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Recent optical and radio observations2 4 of gas motions show a large, central concentration of mass (probably a black hole) in a number of galaxies. But this gas lies beyond ~30,000 Schwarzschild radii so the characteristic signatures of the black hole itself-relativistic ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/375659a0
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  • 5
    Electronic Resource
    Electronic Resource
    Expression of CD44 variants in osteosarcoma (1999)
    Springer
    Journal of cancer research and clinical oncology 125 (1999), S. 646-652 
    Details
    ISSN: 1432-1335
    Keywords: Key words Osteosarcoma ; CD44 ; Immunohisto-chemistry ; Prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The standard form of CD44 (CD44H) is a transmembranous glycoprotein, widely distributed on a variety of human lymphoid cells, epithelial cells and tumours. CD44 has many variant forms, which are generated by alternative splicing. In recent years, CD44 has been reported to be related to the degree of tumour differentiation, tumour cell invasion, and metastasis. We investigated 44 tumour specimens in 39 patients with osteosarcoma immunochemically to analyse the expression of CD44 standard (CD44H) and variant exon-encoded gene products (CD44v3, v4, v5, v6, v7, v9, and v10). Furthermore, the relationship between CD44 expression and the clinical outcome of patients with osteosarcoma was analysed. Membrane accentuation and exclusive cytoplasmic reactivity were analysed as separate staining patterns. Tumour cells and some multinucleated giant cells were markedly stained. CD44H, v3, v4, v5, v6, v7, v9, and v10 were expressed in 85%, 49%, 54%, 59%, 46%, 5%, 28%, and 10% of the specimens respectively. The cumulative 5-year metastasis-free survival was 58% in CD44v6-negative cases and 24% in CD44v6-positive cases (P=0.046). However, the cumulative 5-year metastasis-free survival was not significantly different between cases positive and negative for other variants of CD44. Multivariate analysis (Cox proportional-hazard model) with CD44v6 expression (positive or negative), chemotherapy (intensive or non-intensive), tumour site (proximal or distal), and age (at least 30 years or less than 30 years) showed that expression of CD44v6 and chemotherapy were important prognostic factors in patients with osteosarcoma. Overexpression of CD44 isoforms containing variant v6 is correlated with poor prognosis in patients with osteosarcoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004320050329
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  • 6
    Electronic Resource
    Electronic Resource
    Senescence marker protein-30 (SMP30) enhances the calcium efflux from renal tubular epithelial cells (1999)
    Springer
    Clinical and experimental nephrology 3 (1999), S. 261-267 
    Details
    ISSN: 1437-7799
    Keywords: Key words SMP30 ; Calcium efflux ; Tubular epithelia ; Calcium pump ; Calmodulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background. Senescence marker protein-30 (SMP30), a calcium binding protein, is preferentially expressed in the renal proximal tubules and hepatocytes and is presumed to play a role in Ca2+ homeostasis. Methods. To explore its physiological functions in the tubular cells, we investigated the effect of SMP30 on Ca2+ efflux via the ATP-dependent plasma membrane calcium pump. LLC-PK1 cells were stably transfected with a cDNA encoding SMP30, and the established transfectants were subjected to ATP responses. Results. Overexpression of SMP30 significantly increased Ca2+ efflux under both basal and ATP-stimulated conditions. Inhibition of calmodulin by trifluoperazine abrogated the enhanced Ca2+ efflux, suggesting that SMP30 activated the calmodulin-dependent Ca2+ pump. It is known that Ca2+ superfluous influx induces cellular injury. Compared with mock-transfected cells, LLC-PK1 cells expressing SMP30 showed resistance to cellular death triggered by Ca2+ superfluous influx. Conclusion. These results suggest the possibility that, in renal tubular cells, endogenous SMP30 participates in Ca2+ efflux via activating the calmodulin-dependent Ca2+ pump and thereby confers resistance of the cells against injury caused by high intracellular Ca2+ concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s101570050045
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  • 7
    Electronic Resource
    Electronic Resource
    Alginate oligosaccharides modulate cell morphology, cell proliferation and collagen expression in human skin fibroblasts in vitro (1999)
    Springer
    Archives of dermatological research 291 (1999), S. 432-436 
    Details
    ISSN: 1432-069X
    Keywords: Key words Alginate oligosaccharides ; Collagen ; Human skin fibroblasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Effects of alginate oligosaccharides on cell proliferation and expression of collagen in cultured skin fibroblasts were studied. The oligosaccharides were found to suppress fibroblast proliferation to half the level in control cultures at a dose of 10 mg/ml during a period of 5 days. The inhibition was accompanied by a change in cell shape. The inhibition of cell proliferation was reversible, since depletion of these oligosaccharides led to a recovery of cell motility. Treatment of confluent cells with 10 mg/ml oligosaccharides for 5 days resulted in a reduction in collagen synthesis to one half of that in control cultures and inhibition of steady state levels of α1(I), α2(I), α1(III) and α1(VI) collagen mRNAs. These results suggest that alginate oligosaccharides are potential modulators of dermal fibroblasts and may provide a useful tool for the treatment of disorders related to abnormal collagen metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004030050434
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  • 8
    Electronic Resource
    Electronic Resource
    Overexpression of dominant negative mutant hepatocyte nuclear factor (HNF)-1α inhibits arginine-induced insulin secretion in MIN6 cells (1999)
    Springer
    Diabetologia 42 (1999), S. 887-891 
    Details
    ISSN: 1432-0428
    Keywords: Keywords MODY ; hepatocyte nuclear factor-1α ; recombinant adenovirus ; MIN6 cells ; dominant negative effect ; arginine.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. To explain the mechanisms whereby mutations in the HNF-1α gene cause insulin secretory defects. Methods. A truncated mutant HNF-1α (HNF-1α288 t) was overexpressed in hepatoma cells (HepG2) and murine insulinoma cells (MIN6) using a recombinant adenovirus system and expression of the HNF-1α target genes and insulin secretion were examined. Results. Expression of phenylalanine hydroxylase and α1-antitrypsin genes, the target genes of HNF-1α, was suppressed in HepG2 cells by overexpression of HNF-1α288 t. In MIN6 cells, overexpression of HNF-1α288 t did not change insulin secretion stimulated by glucose (5 mmol/l and 25 mmol/l) or leucine (20 mmol/l). Potentiation of insulin secretion by arginine (20 mmol/l, in the presence of 5 mmol/l or 25 mmol/l glucose) was, however, reduced (p 〈 0.0001 and p = 0.027, respectively). Similarly reduced responses were observed when stimulated with homoarginine. Expression of the cationic amino acid transporter-2 was not reduced and insulin secretory response to membrane depolarization by 50 mmol/l KCl was intact. Conclusion/interpretation. The HNF-1α288 t, which is structurally similar to the mutant HNF-1α expressed from the common MODY3 allele, P291fsinsC, exerts a dominant negative effect. Suppression of HNF-1α in MIN6 cells severely impaired potentiation of insulin secretion by arginine, whereas glucose-stimulated and leucine-stimulated insulin secretion was intact. Our findings delineate the complex nature of beta-cell failure in patients with MODY3. This cell model will be useful for further investigation of the mechanism of insulin secretory defects in these patients. [Diabetologia (1999) 42: 887–891]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250051242
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  • 9
    Electronic Resource
    Electronic Resource
    Involvement of substance P as a mediator in capsaicin-induced mouse ear oedema (1995)
    Springer
    Inflammation research 44 (1995), S. 470-474 
    Details
    ISSN: 1420-908X
    Keywords: Mouse ear oedema ; Capsaicin ; Tachyphylaxis ; Substance P ; NK1 receptor antagonist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We examined the involvement of substance P (SP) in mouse ear oedema induced by topical application of capsaicin (250 µg/ear). Reapplication of capsaicin at 4h, 24h, and 48h after initial treatment did not induce a second oedema response. Oedema induced after the second application was significantly (p〈0.01 orp〈0.001) suppressed for up to 30 days but was observed when capsaicin was applied 40 days after initial treatment. Topical pretreatment of ears with capsaicin at 4h, 24h and 48h before i.v. injection of SP (5 µg/kg) did not cause a significant inhibition of plasma extravasation in ear skin. NK1 receptor antagonists such as RP 67580 (ED50:0.19 mg/kg, i.v.), spantide II (ED50:0.33 mg/kg, i.v.), and GR 82334 (ED50:0.26 mg/kg, i.v.), inhibited capsaicin-induced ear oedema, whereas SR 48968 (2.0 mg/kg, i.v.), a NK2 receptor antagonist, had no effect. Furthermore, RP 67580 (0.5 kg/mg, i.v.) inhibited the oedema response induced by reapplication of capsaicin at 50 days after initial treatment. These results indicate that tachyphylaxis of capsaicin-induced oedema is reversible and suggest that this response may be due mainly to a reduction of SP in sensory neurones but not to any loss of responsiveness of NK1 receptors. We also conclude that SP and NK1 receptors are involved predominantly in the development of capsaicin-induced mouse ear oedema.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01837912
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  • 10
    Electronic Resource
    Electronic Resource
    Increase in the Potential of Osteoblasts to Support Bone Resorption by Osteoclasts In Vitro in Response to Roughness of Bone Surface (1999)
    Springer
    Calcified tissue international 65 (1999), S. 454-458 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Osteoclasts — Rough surface — Bone resorption — Spleen cells — Alkaline phosphatase.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. The development of the potential of osteoblasts to support bone resorption by osteoclasts in response to roughness on bone slices was examined in the co-incubation cell system of immature osteoclasts and osteoblastic cells. The immature osteoclasts, which need alkaline phospatase (ALP)-positive osteoblastic cells for bone resorption, were generated in mouse spleen cultures with 1, 25-dihydroxyvitamin D3 and prostaglandin E2. ALP-negative osteoblastic cells from mouse calvaria were incubated on rough surfaced bone slices for 3 days. The number of ALP-positive cells increased greatly on the rough surface, but little on the smooth surface. When immature osteoclasts were added and incubated for 1 more day, the resorption pit number and the total pit areas on the smooth surface were not much different from those before incubation but were approximately four times higher on the rough surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900732
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