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  • 1
    Digitale Medien
    Digitale Medien
    Mixing enhancement in a lobed injector (1997)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 9 (1997), S. 667-678 
    Details
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: An experimental investigation of the non-reactive mixing processes associated with a lobed fuel injector in a coflowing air stream is presented. The lobed fuel injector is a device which generates streamwise vorticity, producing high strain rates which can enhance the mixing of reactants while delaying ignition in a controlled manner. The lobed injectors examined in the present study consist of two corrugated plates between which a fuel surrogate, CO2, is injected into coflowing air. Acetone is seeded in the CO2 supply as a fuel marker. Comparison of two alternative lobed injector geometries is made with a straight fuel injector to determine net differences in mixing and strain fields due to streamwise vorticity generation. Planar laser-induced fluorescence (PLIF) of the seeded acetone yields two-dimensional images of the scalar concentration field at various downstream locations, from which local mixing and scalar dissipation rates are computed. It is found that the lobed injector geometry can enhance molecular mixing and create a highly strained flowfield, and that the strain rates generated by scalar energy dissipation can potentially delay ignition in a reacting flowfield. © 1997 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.869224
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  • 2
    Digitale Medien
    Digitale Medien
    Laser Raman scattering measurements of differential molecular diffusion in nonreacting turbulent jets of H2/CO2 mixing with air (1995)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 7 (1995), S. 1455-1466 
    Details
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: In this paper we report measurements of differential diffusion in nonreacting jet flows. Pulsed laser Raman scattering spectroscopy is used to measure species concentrations in nonreacting jets of H2/CO2 into air over a range of Reynolds numbers from 1000 to 64 000. Measurements are also made in strained laminar opposed flows of H2/CO2 against air, where differential diffusion effects on relative species concentrations are observed to be independent of strain rate. In laminar opposed flows and in a laminar jet (Re=1000), measurements of average species concentrations show significant differential diffusion effects. In jet flows of higher Reynolds numbers, only instantaneous species concentrations are affected by differential diffusion; measured species concentrations are the same, on average, as the species concentrations that would have been observed if all species diffusivities were equal. Instantaneous differential diffusion effects in turbulent jets are quantified by the variance of a differential diffusion variable z, where z is the difference between the normalized mole fractions of H2 and CO2 (and normalization refers to dividing each species mole fraction by the mole fraction of that species in pure jet fluid). Measurements show that zRMS diminishes with increasing Reynolds number. Histograms of z show negative skewness in the low Reynolds number jet. At higher Reynolds numbers the histograms become more symmetric, although asymmetries do remain at higher Reynolds numbers in the data obtained near the jet edge, where there is an interface between jet fluid and coflowing air. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.868532
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  • 3
    Digitale Medien
    Digitale Medien
    Investigation of substrate-dependent nucleation of plasma-deposited microcrystalline silicon on glass and silicon substrates using atomic force microscopy (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 6041-6046 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: In order to define mechanisms for pulsed-gas plasma enhanced substrate-selective deposition of silicon, the initial stages of microcrystalline silicon (μc-Si) growth by plasma enhanced chemical vapor deposition on both c-Si and glass substrates were investigated by means of atomic force microscopy (AFM) and reflective high energy electron diffraction (RHEED). Differences in initial substrate morphology were reflected in significant differences in film surface morphology in the early stages of growth. AFM images and rms roughness measurements indicated that the initial growth on the c-Si substrate was three dimensional in character. On glass, the initial Si deposits were much more irregular in shape and the tallest features extended over wider areas than the initial deposits on c-Si. The character of the initial growth on glass was partly obscured by the roughness of the substrate, but the appearance of the initial Si deposits suggested a flatter and more two-dimensional character on glass than on c-Si. As the Si deposition progressed, the films on the different substrates developed similar morphology with increasing thickness. On the c-Si substrate, surface coverage was nearly complete at 50 Å. RHEED analysis of the films grown on c-Si revealed the presence of amorphous structure in the early stages of film growth, which began to transition to a randomly oriented μc-Si structure after 40–50 Å of growth. Observed differences in nucleation affirm and clarify proposed mechanisms and limitations for plasma enhanced selective μc-Si deposition. © 1997 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.366471
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  • 4
    Digitale Medien
    Digitale Medien
    Differentiation of Δ4-3-Ketosteroids and Δ1,4-3-Ketosteroids with Isonicotinic Acid Hydrazide (1959)
    s.l. : American Chemical Society
    Analytical chemistry 31 (1959), S. 102-105 
    Details
    ISSN: 1520-6882
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ac60145a020
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  • 5
    Digitale Medien
    Digitale Medien
    Quantitative Application of Kiliani Reaction (1951)
    s.l. : American Chemical Society
    Analytical chemistry 23 (1951), S. 1244-1247 
    Details
    ISSN: 1520-6882
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ac60057a010
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  • 6
    Digitale Medien
    Digitale Medien
    THE DISPOSITION OF [24-3H]CEREBROSTEROL IN DEVELOPING RAT BRAIN (1975)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 25 (1975), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: —The uptake into subcellular fractions of developing rat brain in vivo of intracerebrally injected [4-14C]cholesterol, [24-3H]cerebrosterol, and [24-3H]24-epicerebrosterol was measured for periods up to 30 days following administration. [4-14C]cholesterol was accumulated rapidly in nuclei, nerve endings, and microsomes, more slowly in myelin and mitochondria. [24-3H]cerebrosterol was accumulated rapidly in myelin, nerve endings, and microsomes, more slowly in nuclei and mitochondria. The uptake of [24-3H]24-epicerebrosterol was essentially the same as that of [24-3H]cerebrosterol. Ratios of radioactivities of [24-3H]cerebrosterol and [4-14C]cholesterol accentuated the early accumulation of [24-3H]cerebrosterol in myelin, nerve endings, and microsomes, and declining 3H:14C ratios disclosed the rapid elimination of [24-3H]cerebrosterol and [24-3H]24-epicerebrosterol relative to [4-14C]cholesterol in nerve endings and microsomes. The data suggest that the removal of [24-3H]cerebrosterol from brain results from an enzymic metabolism of the sterol, therefore that cerebrosterol exists in brain in a dynamic state of biosynthesis and catabolism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1471-4159.1975.tb04385.x
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  • 7
    Digitale Medien
    Digitale Medien
    The Response of the Lung to Foreign Compounds that Produce Free Radicals (1986)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physiology 48 (1986), S. 681-692 
    Details
    ISSN: 0066-4278
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Medizin , Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.ph.48.030186.003341
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  • 8
    Digitale Medien
    Digitale Medien
    Morphological and biochemical correlates of chemical induced injury in the lung (1986)
    Springer
    Archives of toxicology 58 (1986), S. 214-218 
    Details
    ISSN: 1432-0738
    Schlagwort(e): Lung damage by chemicals ; Lung damage, cell specificity in ; Lung damage, mechanisms of toxicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We have reviewed some of the factors which contribute to lung damage by various toxicants. These include disposition of the chemical, its metabolism, individual cell type susceptibility and the potential for the tissue to repair. We have discussed the use of biochemical parameters to measure the functional activity of individual cell types in order to predict the damage to specific cell types and concluded that careful morphological analysis of lung tissue is likely to provide a more sensitive and informative measure of specific cell type injury. However, in order to investigate the mechanism of toxicity of pulmonary toxicants it is essential to establish the primary biochemical event that leads to cell damage and morphological change. The importance of separating the relevant biochemical change(s) from the cascade of biochemical events associated with dead and dying cells and the reparative response of the lung is emphasised.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00297108
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  • 9
    Digitale Medien
    Digitale Medien
    From toxicological problem to therapeutic use: The discovery of the mode of action of 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC), its toxicology and development as a drug (1998)
    Springer
    Journal of inherited metabolic disease 21 (1998), S. 498-506 
    Details
    ISSN: 1573-2665
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract NTBC is a triketone with herbicidal activity that has been shown to have a novel mode of action by inhibiting the enzyme 4-hydroxyphenylpyruvate dioxygenase in plants. Early studies on the toxicity of this compound found that rats treated with NTBC developed corneal lesions. Investigations aimed at understanding the mechanistic basis for the ocular toxicity discovered that the rats developed tyrosinaemia and excreted large amounts of 4-hydroxyphenylpyruvate and 4-hydroxyphenyllactate, owing to inhibition of the hepatic enzyme 4-hydroxyphenylpyruvate dioxygenase. The corneal lesions resemble those seen when rats are fed a diet supplemented with tyrosine, leading us to conclude that the ocular toxicity seen with NTBC is a consequence of a marked and sustained tyrosinaemia. Studies in collaboration with Professor Sven Lindstedt showed that NTBC was a potent inhibitor of purified human liver 4-hydroxyphenylpyruvate dioxygenase. This interaction lead to the concept of using NTBC to treat patients with tyrosinaemia type 1, to block or reduce the formation of toxic metabolites such as succinylacetoacetate in the liver. Zeneca Agrochemicals and Zeneca Pharmaceuticals made NTBC available for clinical use and, with the approval of the Swedish Medical Products Agency, a seriously ill child with an acute form of tyrosinaemia type 1 was successfully treated in February 1991. Subsequently, other children with this inborn error of metabolism in Sweden and other countries have been treated with NTBC. The drug is now available to those in need via Swedish Orphan AB.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1005458703363
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  • 10
    Digitale Medien
    Digitale Medien
    Determination of long-lived actinides in soil leachates by inductively coupled plasma-mass spectrometry (1995)
    Springer
    Journal of radioanalytical and nuclear chemistry 194 (1995), S. 133-139 
    Details
    ISSN: 1588-2780
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik
    Notizen: Abstract Inductively coupled plasma-mass spectrometry (ICP-MS) was used to concurrently determine multiple long-lived (t1/2〉104 y) actinide isotopes in soil leachates. Ultrasonic nebulization was found to maximize instrument sensitivity. Instrument detection limits for actinides in solution ranged from 50 mBq L−1 (239Pu) to 2μBq L−1 (235U). Hydride adducts of232Th and238U interfered with the determinations of233U and239Pu; thus, extraction chromatography was used to concentrate the analytes and separate uranium from the other actinides in advance of mass spectrometric determination. Alpha spectrometric determinations of230Th,239Pu, and the234U/238U activity ratio in soil leachates compared well with ICP-MS determinations; however, there were some small systematic differences (ca. 10%) between ICP-MS and α-spectrometric determinations of234U and238U activities. These differences were attributed to the use of different isotope dilution spikes for ICP-MS and α-spectrometry.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02037619
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