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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 64 (1995), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Human immunodeficiency virus (HIV)-1-associated dementia is a frequent consequence of HIV infection and is associated with neuronal deficits. Increased concentrations of the kynurenine pathway metabolites 3-hydroxykynurenine (3-HK) and quinolinic acid (QA) may contribute to this neuronal damage. We measured 3-HK concentrations and the activity of its catabolising enzyme, 3-hydroxykynureninase, in postmortem brain tissue from eight controls and 32 HIV-positive patients, including a group that exhibited dementia. 3-HK concentrations were significantly increased (over threefold) in the HIV-positive group when compared with controls. This increase was greater in those patients with dementia, but it was still apparent in the nondemented cases. 3-Hydroxykynureninase activity was significantly increased in the HIV-infected group compared with the control values. The effect was apparent in both nondementia and dementia cases, although the latter showed a slightly greater increase. The 3-HK content increase is thus unrelated to a reduction in activity of this enzyme and is likely to reflect an overall increase in the kynurenic metabolic pathway. Elevated levels of the neurotoxin 3-HK may contribute to the neuronal deficits underlying HIV-associated dementia.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 27 (1905), S. 1512-1514 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 28 (1906), S. 1220-1222 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 28 (1906), S. 1222-1229 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A 2 mm scattering diagnostic used to study density fluctuations of the electron cyclotron resonance heated plasma in the Advanced Toroidal Facility is described. A four-channel flexible antenna design was chosen to monitor fluctuations within the wave number range of 3〈k⊥〈20 cm−1 and to locate the scattering volume anywhere in the stellarator minor cross section. Special attention was paid to the system calibration and to the normalization of the k spectra. Analysis of the diagnostic noise showed that the main source of spurious signal was a scattering from high-level edge turbulence driven by the second-harmonic radiation from the gyrotron used for plasma heating. This spurious signal was suppressed using waveguide filters and rearrangement of the microwave circuit elements. Evidence in support of direct scattering from a well-defined plasma volume was found. Good correlation of the scattered waves' intensity with the density scale length was observed. Use of a dual-homodyne circuit configuration made is possible to determine that the plasma density fluctuations were propagating in the electron diamagnetic direction. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A 2 mm scattering diagnostic used to study density fluctuations of the electron cyclotron resonance heated plasma in the Advanced Toroidal Facility is described. A four-channel flexible antenna design was chosen to monitor fluctuations within the wave number range of 3〈k⊥〈20 cm−1 and to locate the scattering volume anywhere in the stellarator minor cross section. Special attention was paid to the system calibration and to the normalization of the k spectra. Analysis of the diagnostic noise showed that the main source of spurious signal was a scattering from high-level edge turbulence driven by the second-harmonic radiation from the gyrotron used for plasma heating. This spurious signal was suppressed using waveguide filters and rearrangement of the microwave circuit elements. Evidence in support of direct scattering from a well-defined plasma volume was found. Good correlation of the scattered waves' intensity with the density scale length was observed. Use of a dual-homodyne circuit configuration made is possible to determine that the plasma density fluctuations were propagating in the electron diamagnetic direction. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Density fluctuations in low-collisionality, low-beta (β∼0.1%), currentless plasmas produced with electron cyclotron heating (ECH) in the Advanced Toroidal Facility (ATF) torsatron [Fusion Technol. 10, 179 (1986)] have been studied using a 2 mm microwave scattering diagnostic. Pulsed gas puffing is used to produce transient steepening of the density profile from its typically flat shape; this leads to growth in the density fluctuations when the temperature and density gradients both point in the same direction in the confinement region. The wave number spectra of the fluctuations that appear during this perturbation have a maximum at higher k⊥ρs (∼1) than is typically seen in tokamaks. The in–out asymmetry of the fluctuations along the major radius correlates with the distribution of confined trapped particles expected for the ATF magnetic field geometry. During the perturbation, the relative level of the density fluctuations in the confinement region (integrated over normalized minor radii ρ from 0.5 to 0.85) increases from ñ/n∼1% when the density profile is flat to ñ/n∼3% when the density profile is steepened. These observations are in qualitative agreement with theoretical expectations for helical dissipative trapped-electron modes (DTEMs), which are drift-wave instabilities associated with particle trapping in the helical stellarator field; they suggest that trapped-electron instabilities may play a role in constraining the shape of the density profile in ATF, but have little effect on global energy confinement. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1365-2095
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: In order to enhance growth, survival and quality during early juvenile stages of marine fish it is important to avoid lipid oxidation problems that are known to cause pathologies and disease. The aim of the present study was to characterize and compare the antioxidant systems in juvenile marine fish of commercial importance in European aquaculture, namely turbot (Scophthalmus maximus), halibut (Hippoglossus hippoglossus) and gilthead sea bream (Sparus aurata). The experiment investigated the interaction of the dietary antioxidant micronutrient, vitamin E, with antioxidant defence systems. Fish were fed with diets of identical unsaturation index supplemented with graded amounts of vitamin E. The relationships between dietary and subsequent tissue vitamin E levels were determined as well as the effects of vitamin E supplementation on lipid and fatty acid compositions of both liver and whole fish, on the activities of the liver antioxidant defence enzymes, and on the levels of liver and whole body lipid peroxidation products, malondialdehyde (thiobarbituric acid reactive substances, TBARS) and isoprostanes. Growth and survival was only significantly affected in sea bream where feeding the diet with the lowest vitamin E resulted in decreased survival and growth. A gradation was observed in tissue vitamin E and polyunsaturated fatty acid (PUFA)/vitamin E levels in response to dietary vitamin E levels in all species. The activities of the main radical scavenging enzymes in the liver, catalase, superoxide dismutase and glutathione peroxidase generally reflected dietary and tissue vitamin E levels being highest in fish fed with the lowest level of vitamin E. The indicators of lipid peroxidation gave consistent results in all three species, generally being highest in fish fed with the unsupplemented diet and generally lowest in fish fed with the diet with highest vitamin E. In this respect, isoprostane levels generally paralleled TBARS levels supporting their value as indicators of oxidative stress in fish. Overall the relationships observed were logical in that decreased dietary vitamin E led to decreased levels of tissue vitamin E, and generally higher activities of the liver antioxidant enzymes and higher levels of lipid peroxides.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Anaesthesia 55 (2000), S. 0 
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Anaesthesia 55 (2000), S. 0 
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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