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  • Articles: DFG German National Licenses  (12)
  • 1990-1994  (12)
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  • Articles: DFG German National Licenses  (12)
Material
Year
  • 1
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 5428-5434 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Optical emission spectroscopy has been established as a valuable method for the analysis of broad oxygen ion beams. The ion beams used for reactive ion-beam etching have been investigated in the energy range of 300–1500 eV. From survey spectra O+2 molecules and neutral O atoms are identified as main emitting species. Concerning the occurrence of emission lines the beam spectrum resembles that obtained from an O2 rf plasma. The intensity ratios however are strongly different within both spectra. Whereas electron impact is the main source for electronic excitation in ordinary etch plasmas, heavy particle collisions are suggested to play an important role in the investigated ion beams. Beam-induced emissions of atomic oxygen neutrals were recorded at high resolution of 0.1 A(ring). The O emission lines were found to be triple peaked. One peak at the unshifted wavelength and two Doppler-shifted peaks could be resolved. The absolute values of the wavelength shifts are well correlated to the energies of the initial ions extracted from the ion source by a grid optics. Besides slow atoms, atoms moving with the full beam energy as defined by the ion extraction conditions and with only half the beam energy are detected. The observed Doppler structure is attributed to charge exchange and dissociative collisions taking place in the gas phase.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 7517-7520 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In a reactive ion beam etching system, gas phase collision processes in the reaction chamber were identified from the energy distributions of positive ions originating from source plasmas with O2, SF6, and CF4 as feed gases. The ion energy distributions are determined by a quadrupole mass spectrometer for main beam energies below 500 eV at typical working pressures in the reaction chamber of 1–10×10−2 Pa. Besides near thermal ions a considerable amount of high energy fragmentation products were detected for a number of primary molecular ions. The relative intensities of these products compared to the parent ions suggest a non-negligible influence of gas phase dissociation processes on the etch or deposition characteristics of molecular ion beams and the resulting properties of surfaces treated under elevated working pressure conditions.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 2393-2393 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Broad low-energy ion beams in the energy range of 0.2 to 1.5 keV originating from a filament source with argon as feed gas have been analyzed by high-resolution emission spectroscopy. The Doppler structure of Ar+ emissions reveals the existence of different velocity classes. Besides slow ions and ions possessing the main beam energy, electronically excited Ar+ ions with twice the main beam energy are detected which are attributed to a single-electron capture process in Ar++/Ar collisions. As a preliminary result from a reactive beam extracted from a microwave CF4 source, plasma fast F atoms are detected which are attributed to charge exchange and dissociative collisions in the process chamber.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 3063-3067 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Broad ion beams in the energy range of 0.2 to 1.5 keV originating from a filament source with argon as feed gas have been analyzed by high-resolution emission spectroscopy. The Doppler structure of Ar+ emissions reveals the existence of different velocity classes. Besides slow ions and ions possessing the main beam energy, electronically excited Ar+ ions with twice the main beam energy are detected which are attributed to a single-electron capture process in Ar++/Ar collisions. As a preliminary result from a reactive beam extracted from a microwave CF4 source plasma fast F atoms are detected which are attributed to charge exchange and dissociative collisions in the process chamber.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1520-6025
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 3635-3640 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The behavior of CF2 radicals in CF4/O2 plasmas has been studied as a function of the oxygen partial pressure in an rf reactor with 13.56 MHz, 30 W, and 40 mTorr total pressure. The CF2 ground and excited states were detected by the CF2 (A-X) band spectra applying laser-induced fluorescence and optical emission spectroscopy, respectively. Adding oxygen to the CF4 feed gas, the intensity of the CF2 signals in both spectra showed similar decrease. No evidence is found for a simple correlation between the neutral CF2 densities and the CF+2 ions measured by quadrupole mass spectrometry. Electron densities and temperatures were evaluated to be slightly above 8×109 cm−3 and ∼5 eV, respectively. A simplified model, which takes into account different excitation paths, suggests that direct electron impact of the CF2 ground state species was the dominant mechanism for the population of the electronically excited state. Absolute CF2 and O concentrations depending on the oxygen feed could be estimated. We obtained CF2 densities between 2×1013 and 2×1012 cm−3, when the oxygen concentration increases from 2% to 23%. The corresponding O densities varied from 1012 to 6×1013 cm−3.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology ecology 8 (1991), S. 0 
    ISSN: 1574-6941
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 85 (1991), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract By degrading the settlement inducer gamma-aminobutyric acid (GABA), bacteria may affect the larval settlement of sedentary marine invertebrates. Nearly one third of bacterial isolates from surfaces suitable for abalone (Haliotis) settlement were able to grow on GABA as sole carbon source. Compared with similar compounds, GABA was a good source of carbon, nitrogen and energy, and it was utilized concomitantly with glucose. GABA-metabolizing enzymes were constitutive in Pseudomonas fluorescens and inducible in Aeromonas hydrophila. High-affinity (Km: 20–50 μM) and low-affinity (Km: 7–9 mM) uptake systems were produced in response to low and high GABA concentrations, respectively, in the growth medium. Within the ecologically significant temperature range (12–24°C), specific GABA degradation rates varied 2.5-fold in young cells of P. fluorescens. This organism los its ability to degrade GABA during the stationary phase. The results suggest that marine bacteria have the potential to affect invertebrate larval settlement by removing GABA from the settlement habitat.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1439-0973
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die geringe Ansprechrate der Lyme-Arthritis auch bei intravenöser und hochdosierter Gabe von Penicillin G hat das Interesse an neueren Antibiotika zur Behandlung der Lyme-Borreliose im Spätstadium erhöht. Wie schon auf Grund vorliegender In-vitro-Daten zur Empfindlichkeit vonBorrelia burgdorferi erwartet werden konnte, sind Cephalosporine der dritten Generation sehr viel effektiver als Penicillin G. In der hier vorgestellten randomisierten prospektiven Untersuchung wurde deshalb Cefotaxim in einer Dosierung von 2 × 3 g täglich mit Penicillin G in einer Dosierung von 2 × 10 Mega-Einheiten verglichen. 135 Patienten, bei denen eine definierte klinische Symptomatik im Sinne einer Stadium-3-Borreliose für mindestens sechs Monate bestanden hatte und bei denen Antikörper gegenB. burgdorferi nachweisbar waren, wurden in die Studie aufgenommen. Die Patienten wurden 24 Monate nachbeobachtet und im Abstand von drei Monaten reevaluiert. Die mit Cefotaxim behandelten Patienten zeigten ein signifikant besseres Therapieergebnis. Während in der Penicillin-Gruppe nur 61,3% der Patienten eine Voll- oder Teilremission ihrer Beschwerden zeigten, konnte dies bei der Cefotaxim-Gruppe bei 87,9% der Patienten erreicht werden (p=0,002). Parallel zum klinischen Effekt war ein Absinken der Antikörpertiter im Immunfluoreszenztest zu beobachten. Herxheimer-artige Reaktionen waren bei 20% der Patienten der Penicillin-Gruppe und bei 40,5% der Patienten der Cefotaxim-Gruppe zu beobachten. Diese Reaktion kann als Hinweis auf ein Ansprechen der Therapie gewertet werden.
    Notes: Summary The low responsiveness of Lyme arthritis to high dose intravenous penicillin G therapy has evoked the demand for new drugs for the treatment of late stage borreliosis. As can be deduced fromin vitro susceptibility data, third generation cephalosporins are far more effective onBorrelia burgdorferi spirochetes than penicillin G. The study presented here was designed to compare cefotaxime at a dosage of 2 × 3 g/day with penicillin G at a dosage of 2 × 10 megaunits/day, for ten days in a prospective randomized trial. A total of 135 patients were included in the study. They were diagnosed to suffer from late stage Lyme borreliosis on the basis of defined clinical symptoms compatible with stage three borreliosis manifestations of at least six months' duration and positive antibody titers againstB. burgdorferi. Final outcomes were recorded after a 24 month post-treatment observation period with re-examination at three-month-intervals. Cefortaxime proved to be significantly superior to penicillin G with 87.9% versus 61.3% of treatments resulting in full or incomplete remission of symptoms (p=0.002). Clinical remission was accompanied by declining antibody titers. Herxheimer-like reactions were observed in 20% of the patients of the penicillin group and in 40.5% of the patients of the cefotaxime group and may be interpreted as an indication of a response to therapy.
    Type of Medium: Electronic Resource
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