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  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 1225-1232 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Low-temperature photoluminescence (PL) spectra were investigated for CuAlSe2 epilayers grown on GaAs(001) substrates by means of low-pressure metalorganic chemical-vapor deposition. PL properties were studied with relation to metalorganic precursors used for the growth. High-quality undoped epilayers exhibited PL peaks related to a free exciton (2.739 eV) and a bound exciton (2.677 eV). The other undoped epilayers exhibited PL bands at 2.3, 2.4, and 2.5 eV originating from donor-acceptor (D-A) pair recombinations. Some of them were found to have a common activation energy for the thermal quenching of 50±10 meV. The PL spectrum changed drastically by impurity doping. Intense green emissions at 2.51 and 2.43 eV were observed in Zn and Mg-doped epilayers, respectively, which were interpreted as D-A pair recombinations based on the dependencies of the PL spectra on excitation intensity, decay time, and temperature. The donor and the acceptor activation energies (ED and EA) were estimated to be 110 and 230 meV, respectively, for the Zn-related D-A pair emission at 2.51 eV. Similarly, ED and EA for CuAlSe2:Mg were estimated to be 140±10 and 270±10 meV, respectively. Furthermore, D-A pair recombinations between 2.3 and 2.5 eV for CuAlSe2:I were studied. CuAlSe2 was proven to be a promising material for short-wavelength visible-light-emitting devices. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 3338-3345 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: CuAlxGa1−xSe2 alloy layers were successfully grown on GaAs(001) by low-pressure metalorganic vapor phase epitaxy. The distribution coefficient of Al was unity. All alloy layers had their c-axis normal to the substrate plane. Exciton resonance energies were determined as a function of x by means of photoreflectance measurements. A quadratic dependence of exciton energies on x was confirmed. The spin-orbit splittings of the epilayers were approximately the same as that of bulk crystals. The magnitudes of crystal-field splittings were larger than that of bulk crystals, and this was explained in terms of residual tensile biaxial strain in the epilayers. The color of the low-temperature photoluminescence (PL) changed from red to crimson, orange, yellow, green, and bluish-purple with increasing x. A peak due to a free-to-acceptor transition was dominant in the PL spectra of the alloy layers. The acceptor ionization energy increased with increasing x, and the result may reflect an increase of the hole effective mass. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Chester : International Union of Crystallography (IUCr)
    Journal of synchrotron radiation 5 (1998), S. 1013-1015 
    ISSN: 1600-5775
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Geologie und Paläontologie , Physik
    Notizen: An experimental system for polarized soft X-ray Raman scattering spectroscopy has been constructed. The soft X-ray spectrometer is based on the Rowland circle geometry with a holographic spherical grating. Three types of gratings are used to cover the energy range from 18 eV to 1200 eV. According to a ray-trace simulation, the resolution is expected to be 200 meV at 700 eV by using a 10 µm slit width. The polarized and depolarized soft X-ray Raman scattering spectra can be measured by rotating the soft X-ray spectrometer around the axis of the incident beam. Preliminary measurements of polarized and depolarized spectra were accomplished at undulator beamline BL-2C of the Photon Factory.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 30 (1974), S. 1452-1459 
    ISSN: 1600-5740
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 30 (1974), S. 726-730 
    ISSN: 1600-5740
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 27 (1971), S. 785-786 
    ISSN: 1420-9071
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Résumé A cause du comportement des indices polygraphiques et surtout du fait de provocation par des stimuli d'éveil, on conclut que le grincement des dents pendant le sommeil se manifeste comme une sorte de réaction d'éveil.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Chester : International Union of Crystallography (IUCr)
    Journal of synchrotron radiation 4 (1997), S. 256-260 
    ISSN: 1600-5775
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Geologie und Paläontologie , Physik
    Notizen: The soft X-ray emission spectra of Si and cubic boron nitride (cBN) are compared in the Si2p- and B1s-core exciton regions because inversion symmetry is lost and the band gap is extremely large for cBN although both crystal structures are very similar. The background in the soft X-ray emission spectrum of Si is much larger than that for cBN but becomes extremely weak as the excitation energy becomes low and the Raman process becomes dominant compared with the fluorescence process. The background is found to be mainly formed by electron excitation from the valence band to the conduction band. The Raman spectrum is similar to the absorption spectrum in cBN, while those of Si are quite different from each other. It is shown that the centrosymmetry is important in the selection rule of Raman scattering. In resonant Raman scattering the selection rule partly breaks down due to the lattice relaxation process that emits an ungerade phonon in the intermediate state.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1420-908X
    Schlagwort(e): Granulocyte colony-stimulating factor ; Neutrophil migration ; Complement ; Kinin ; Cyclo-oxygenase-2
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Administration of human recombinant granulocyte colony-stimulating factor (G-CSF, 100 μg/kg/day, s.c) to rats for 4 days significantly increased circulating neutrophil counts (by 1130%), together with an increase in mononuclear leukocyte counts (by 119%). Infiltrated pleural neutrophil counts in G-CSF-treated rats (G-CSF-r) 5h after the intrapleural injection of zymosanactivated serum were significantly higher (by 155%) than those in control rats (Vehicle-r). In carrageenin-induced pleurisy, counts of infiltrated pleural neutrophils in G-CSF-r 5 and 7h after carrageenin were significantly higher (by 119% and 116%) than those in Vehicle-r. G-CSF treatment increased the volume of pleural exudate and the plasma exudation rate by 122% and 226%, compared to values in Vehicle-r 5h after carrageenin. Cobra venom factor (75 μg/kg, i.v.) significantly reduced pleural neutrophil migration in G-CSF-r (by 53%) and Vehicle-r (by 49%). Bromelain (10 mg/kg, i.v.) and aspirin (100 mg/kg, p.o.) reduced pleural neutrophil migration and reduced exudate volume and plasma exudation. Intrapleural bradykinin-(1–5) and prostaglandin E2 levels were significantly higher in G-CSF-r than in Vehicle-r. The increased neutrophil migration in G-CSF-r may be atributed to enhanced activation of the complement system facilitated by increased plasma exudation due to bradykinin and prostaglandins.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Inflammation research 47 (1998), S. 107-111 
    ISSN: 1420-908X
    Schlagwort(e): Key words: Carrageenin pleurisy — NS-398 — Proliferative inflammation — Angiogenesis — Gastric ulcer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. Cyclooxygenase (COX)-2 was induced in an acute exudative inflammatory model (rat carrageenin-induced pleurisy) in which prostaglandin E2, 6-keto-prostaglandin F1α, and thromboxane B2 were generated in the pleural fluid. Selective COX-2 inhibitors, such as NS-398, inhibited the plasma exudation and generation of prostaglandin E2, but not that of thromboxane B2 and 6-keto-prostaglandin F1α, in the pleural fluid. In proliferative inflammatory models, COX-2 was induced, and selective COX-2 inhibitors suppressed granuloma formation, particularly, microvessel formation. COX-2 was induced during angiogenesis in a sponge model implanted into skin of rat, and the COX-2 inhibitor suppressed the angiogenesis. As induction of COX-2 was reported in osteoblasts, COX-2 was involved in most characteristic responses of acute exudative inflammation, granuloma formation, bone resorption, and pain in rheumatoid arthritis. The prevention of these COX-2 responses provides a rationale for the effectiveness of COX-2 inhibitors in the treatment of rheumatoid arthritis.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1432-8798
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary.  We analyzed 57 HIV-1 isolates from Cameroon and the Republic of Congo, with respect to the env C2V3 and/or the pol integrase regions. The results indicated that the topology of the pol tree correlated well with that of the env tree for four clusters of subtype D, F G and H, suggesting that these trees reflect the true evolution of the overall genome structures of these subtypes. However, of 22 Cameroonian isolates that were classified as subtype A based on env, 20 of them diverged in their pol sequence into two lineages that were completely different from the prototypical subtype A, tentatively designated as subtypes A1 and A2. The subtype A1 isolates (6 out of 22) were related in their env C2V3 regions with prototypical subtype A strain, but in their pol regions, they formed an independent cluster that diverged from known HIV-1 subtypes so far reported (except for subtypes I and J). The subtype A2 isolates (14 out of 22), which represent the major epidemic type of HIV-1 in Cameroon, clustered distinctly in both the env and pol trees with the recently described A/G mosaic strains from Nigeria and Djibouti. These two lineages were not spreading in the neighboring Republic of Congo.
    Materialart: Digitale Medien
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