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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry 42 (1950), S. 2241-2248 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 60 (1989), S. 1129-1139 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An electrically heated wire-mesh apparatus for pyrolysis studies has been developed which uses computer-driven feedback control for the heating system and thus can apply virtually any time-temperature history to the sample. Internal components are water cooled to prevent heat buildup during long runs. Using this system, coal pyrolysis has been studied at heating rates from 0.1 to about 5000 K/s and temperatures up to 1000 °C. Alternating current is used for heating; this allows the thermocouples to be attached directly to the sample holder and also makes power regulation relatively simple. For atmospheric-pressure experiments, a gas sweep can be forced through the sample holder to remove products from the heated zone and also to concentrate them in a trap which can be removed from the apparatus and weighed to establish tar yields directly. Although the design is optimized for atmospheric-pressure operation, relatively simple modifications allow operation under vacuum or at pressures of up to 160 bars in inert gas or hydrogen. The apparatus has been used to investigate a number of phenomena in coal pyrolysis and, most significantly, has demonstrated the existence of a heating-rate effect which is independent of reactor geometry.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 26 (1976), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— Ataxic and non-ataxic lambs reared under field conditions which gave rise to low copper status were treated with copper intravenously. Untreated ataxic animals served as controls. The neurotransmitter amines, dopamine, norepinephrine and serotonin, were determined in the anterior and posterior regions of the brain stem. Dopamine levels in the anterior region, including the corpus striatum, were significantly lower in the untreated animals than in those treated with copper. Norepinephrine levels were also lower but serotonin concentrations were not different. Plasma amine oxidase activity was markedly higher in the copper treated animals but monoamine oxidase activity in brain stem homogenates was not significantly affected. The monoamine oxidase activity in cortical and cerebellar homogenates was significantly lower in the treated animals than in the untreated animals.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Clinical and experimental pharmacology and physiology 10 (1983), S. 0 
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. The possibility that serotonin (5HT) nerve endings in the dorsomedial medulla oblongata participate in the control of blood pressure was investigated in stroke-prone hypertensive rats and in normotensive rats.2. 5HT nerves were destroyed by injecting 5,7-dihydroxytryptamine bilaterally into the solitary tract nucleus. Immunohistochemical and biochemical examination revealed a selective loss of 5HT nerves throughout the dorsomedial medulla with little damage in adjacent regions.3. Arterial blood pressure and heart rate, measured at daily intervals, were similar in lesioned and sham-operated normotensive rats. However, in the hypertensive rats, blood pressure was substantially elevated at 6-9 days after the lesions compared with sham operations. There were no accompanying changes in heart rate.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1546-1718
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Oculocutaneous albinism (OCA) is a genetically heterogeneous hypopigmentation disorder. One of the two major autosomal recessive forms involves the tyrosinase gene (OCA1), while the other form (OCA2) has recently been associated with alterations of the P gene on chromosome 15. OCA2 is about twice ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 233 (1971), S. 491-492 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] There is little evidence that (d) and (e) are significant except possibly in isolated cases, whereas (c) is probably important only at the start of the corrosion process due to the eventual formation of protective sulphide films in the presence of free sulphide ion6. Much support for (a), the ...
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 71 (1970), S. 196-198 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The abnormally high resistance of certain marine strains of the sulphate-reducing bacteria to the bacteriostatic effects of cetyltrimethylammonium bromide (CTAB) has been studied. A strain of the NaCl-requiring species Desulfovibrio salexigens and a halotolerant strain of D. desulfuricans both showed a marked increase in resistance to CTAB (about one-hundredfold for the former organism) with increasing salinity of the growth medium: this was attributed to enhanced micelle formation by CTAB in presence of NaCl.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 276 (1984), S. 313-316 
    ISSN: 1432-069X
    Keywords: Tyrosine uptake ; Human hairbulbs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A method for measuring tyrosine uptake by human hairbulbs was developed to further characterize the process of melanin formation in human tissue. Uptake was determined by incubating fresh anagen hairbulbs in 14C-tyrosine in HEPES-Tris buffer containing cycloheximide and catalase. Uptake for 11 normally pigmented subjects with brown, black, blond and red hair ranged from 295 cpm/24h per hairbulb for hairbulbs from a blond subject to 6661 cpm/24h per hairbuld for hairbulbs from a red-haired subject. Hairbulbs from a type IIA (tyrosinase-positive) oculocutaneous albino and an uptake of 2995 cpm/24 h per hairbulb. White hairbulbs had an uptake of 265 cpm/ 24h per hairbulb. There was a good correlation (r=0.86) between the level of uptake and the level of tyrosinase (tyrosine hydroxylase) activity when these values were compared for ten subjects. Uptake was reduced with the inhibition of tyrosinase activity. Uptake was also reduced with low incubation temperatures (4° and 21°C) and with the addition of unlabeled tyrosine to the incubation. From 14% to 19% of the 14C-tyrosine that was taken up could be extracted as 14C-melanin. These results show that the uptake of tyrosine as determined by this experimental method is dependent on the presence of melanocytes and tyrosinase, is quantitatively related to the level of tyrosinase activity, and appears to be a metabolic process. Type IIA albino hairbulb melanocytes appear able, to transport adequate amounts of substrate.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Experiments in fluids 13 (1992), S. 305-314 
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A boundary-layer transition study on a sharp, 5° half-angle cone at various angles of attack was conducted at Mach 3.5. Transition data were obtained with and without significantly reduced freestream acoustic disturbance levels. A progressive downstream and upstream motion of the transition front on the windward and leeward rays, respectively, of the cone with angle of attack was observed for the high noise level data in agreement with data trends obtained in conventional (“noisy”) wind tunnels. However, the downstream movement was not observed to the same degree for the low noise level data in the present study. Transition believed to be crossflow dominated was found to be less receptive to freestream acoustic disturbances than first-mode (Tollmien-Schlichting) dominated transition. The previously-developed crossflow transition Reynolds number criterion, χ tr,max ≈200, was found to be inadequate for the current case. An improved criterion is offered, which includes compressibility and flow-geometry effects.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Space science reviews 70 (1994), S. 421-446 
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Auroral images acquired by satellite instrumentation have proven to be a crucial component of the scientific equiry into the physical processes of the Earth's magnetosphere. TheFreja mission provided an opportunity to extend these measurements into the temporal and spatial regime commonly associated with ground-based optical imagers. Employing the basic procedure used successfully in theViking program allowed image repetition rates of 6 s to be achieved with simultaneous exposure of all pixels within the field-of-view. Typical exposure times of 0.3 s required development of an improved image intensifier system and operational requirements resulted in image formats covering approximately one-third of a spin. Simultaneously exposing two broad-band UV cameras, the instrument generates in its normal operational mode 264.6 kbytes per image pair. Results from initial operations confirm the design approach and suggest such imagers can be routinely included on challenging low cost missions such asFreja.
    Type of Medium: Electronic Resource
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