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  • 1990-1994  (16)
  • 1960-1964  (1)
  • 1940-1944
  • 1930-1934
  • 1993  (16)
  • 1963  (1)
  • 1
    Electronic Resource
    Electronic Resource
    A novel medium-energy ion emitter for active spacecraft potential control (1993)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2293-2297 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An ion emission instrument has been developed to actively control the electrostatic surface potential of a spacecraft in orbit. Spacecraft surfaces tend to charge positive when their conductive surfaces are partially sunlit, and photoelectrons emitted, and the spacecraft is positioned outside of the very dense plasma region which is referred to as plasmasphere. A small, lightweight instrument with a lifetime of more than 104 h at a nominal emission current of 10 μA was the design goal. The ion emitter is based on the liquid metal ion source principle; a constant stream of liquified indium is evaporated from the tip of a needle and ionized; the ions are then extracted by a strong electric field. The size of the instrument is about 18 by 15 by 23 cm (length×width×height) and the entire instrument weighs about 1.9 kg and consumes 2.4 W of electrical power in the nominal emission mode. An instrument of this type is already operational on the Japanese Geotail spacecraft, while five more instruments are at the stage of flight model assembly for integration on the Russian Interball satellite and the ESA/NASA four-spacecraft Cluster mission. The Geotail instrument is functioning as expected. Preliminary results show that the ion emitter is able to reduce surface potentials of +70 V (highest value observed up to now) down to 2–4 V.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143924
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The role of hydrogen bonding in carbohydrates: molecular dynamics simulations of maltose in aqueous solution (1993)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 97 (1993), S. 958-966 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100106a024
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Screening for thyroid disorders in a working population (1993)
    Springer
    Journal of molecular medicine 71 (1993), S. 126-131 
    Details
    ISSN: 1432-1440
    Keywords: Subclinical thyroid disorders ; Sonography ; Epidemiology ; Goiter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Subclinical thyroid disorders have received increasing attention in recent years due to refined laboratory methods and a stronger emphasis on the role of preventive medicine. We performed a screening for thyroid-stimulating hormone (TSH) on 6884 persons in a working population. In cases in which TSH was not within the normal range we also measured the levels of triiodothyronine (T3), thyroxine (T4), and thyroxine-binding globulin (TBG). All persons who did not present with exclusion criteria or other nonthyroidal illnesses (n = 59) and the controls (n = 39) were submitted to thyrotropin-releasing hormone (TRH)-testing. Additionally, sonography of the thyroid was performed on 120 persons (59 subjects with abnormal hormone levels and 61 controls) to determine thyroid size and rule out morphological abnormalities. Based on the TRH test and T3, T4, and TBG measurements we found a prevalence of 0.03% (2/6884) for overt hyperthyroidism, 0.33% (23/6884) for subclinical hyperthyroidism, 0.09% (6/6884) for subclinical hypothyroidism, and 0.015% (1/6884) for overt hypothyroidism in the healthy population. In subjects with overt or subclinical hyperthyroidism the prevalence of goiters (thyroid volume 〉 18 ml in women, 〉 25 ml in men) was 28%. Of this group 48% had structural abnormalities. All persons with goiters and/or structural abnormalities were over 35 years of age. Among the euthyroid, 20% had thyroid enlargement, and the same proportion presented with structural abnormalities. There were no differences between the two age groups. In the group with overt/subclinical hypothyroidism 47% presented with structural abnormalities of the thyroid; however, none presented with thyroid enlargement. Thyroid nodules were found only in older persons (〉 〉 35 years) with euthyroidism or hypothyroidism. These data confirm the relatively high prevalence of functional and morphological abnormalities of the thyroid. An early substitution with iodine is warranted to prevent functional and morphological disorders of the thyroid in older age. People with subclinical hyperthyroid disorders must avoid exposure to iodine, which can cause an exacerbation of the disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00179993
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  • 4
    Electronic Resource
    Electronic Resource
    Internal Friction Study of the Oxygen Snoek Relaxation in NbH〈sub〉x〈/sub〉 (0〈x〈0.83) (1993)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 119-121 (Jan. 1993), p. 133-138 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/59/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.119-121.133.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    Small reduction of capsaicin-induced neurogenic inflammation in human forearm skin by the glucocorticoid prednicarbate (1993)
    Springer
    Inflammation research 38 (1993), S. C31 
    Details
    ISSN: 1420-908X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Capsaicin applied to human skin provokes a response known as neurogenic inflammation. Neuropeptides (substance P, CGRP), released from afferent C-fiber terminals and histamine, secondarily released from mast cells, are supposed to participate in this reaction. We investigated the contribution of arachidonic acid and metabolic products to neurogenic inflammation, using a potent topically applied glucocorticoid and the corresponding vehicle. Arachidonic acid is liberated from membrane phospholipids by phospholipase A2, an enzyme that can be blocked by glucocorticoids. In 12 healthy volunteers, neurogenic inflammation was induced by capsaicin 1% on both upper forearms after 16 h of topical pretreatment with either prednicarbate or vehicle. Neurogenic inflammation was assessed by laser Doppler flowmetry and by planimetry of flare sizes. Prednicarbate significantly reduced the laser Doppler flow values inside the flare responses, as well as the flare sizes themselves. These results show that to some extent glucocorticoids reduce capsaicin-induced neurogenic inflammation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01991128
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  • 6
    Electronic Resource
    Electronic Resource
    Cyclooxygenase inhibitors acetylsalicylic acid and indomethacin do not affect capsaicin-induced neurogenic inflammation in human skin (1993)
    Springer
    Inflammation research 38 (1993), S. C25 
    Details
    ISSN: 1420-908X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Neurogenic inflammation is evoked by neuropeptides released from primary afferent terminals and, presumably, by other secondarily released inflammatory mediators. This study examines whether prostaglandins might participate in the development of neurogenic inflammation in humans and whether cyclooxygenase inhibitors have any anti-inflammatory effect on this type of inflammation. In healthy volunteers, neurogenic inflammation was elicited by epicutaneously applied capsaicin (1%), after systemic pretreatment with acetylsalicylic acid, or topically applied indomethacin compared to pretreatment with saline or vehicle, respectively. The extent of neurogenic inflammation was quantified by planimetry of visible flare size and recording the increase of superficial cutaneous blood flow (SCBF) with a laser Doppler flowmeter. Capsaicin-induced flare sizes and outside SCBF (both representing neurogenically evoked inflammation) were unaffected by acetylsalicylic acid or indomethacin. Only the capsaicin-induced increase of inside SCBF was attenuated by local pretreatment with indomethacin, reflecting the participation of prostaglandins in the inflammatory response of those areas which were in direct contact with capsaicin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01991126
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  • 7
    Electronic Resource
    Electronic Resource
    The effects of phorbol ester on slowly conducting afferents of the cat's knee joint (1993)
    Springer
    Experimental brain research 92 (1993), S. 391-398 
    Details
    ISSN: 1432-1106
    Keywords: Joint afferents ; Nociception ; Transduction ; Phorbol esters ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of β -phorbol 12, 13-dibutyrate (PDBu) on the discharge properties of slowly conducting knee joint afferents (group III and group IV fibers) were studied to determine the role of protein kinase C in nociception. Extracellular single unit recordings were made from small filaments dissected from the medial articular nerve in cats anesthetized with alphachloralose. PDBu was applied intra-arterially close to the joint in concentrations of 10-6 up to 10-4 M. The afferents were classified as low-threshold and high-threshold units with regard to their sensitivity to passive noxious and innocuous movements of the knee joint. Following PDBu application, an excitation occurred in 28% of the group III and in 40% of the group IV fibers. An enhancement of responses to passive movements of the joint (sensitization) occurred in 37% of group III and 19% of group IV afferents. In summary, 37.5% of the low-threshold and 50% of the high-threshold fibers proved to be sensitive to PDBu. Most of the PDBu-positive units responded also to bradykinin, whereas only a few PDBu-positive units were sensitive to prostaglandin I2 and E2. We conclude from these results that, in a distinct population of slowly conducting joint afferents, protein kinase C is likely to be involved in the process of transduction. Thus, pain and hyperalgesia may be mediated at least partly by intracellular mechanisms that are linked to protein kinase C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229027
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    Präsynaptische Hemmung im Nucleus cuneatus der Katze (1963)
    Springer
    Pflügers Archiv 278 (1963), S. 78-79 
    Details
    ISSN: 1432-2013
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00672589
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  • 9
    Electronic Resource
    Electronic Resource
    Constants underlying frequency changes in biological rhythmic movements (1993)
    Springer
    Biological cybernetics 68 (1993), S. 421-430 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract When an animal increases or decreases the frequency of its limb motions, how should the transformation in timing be characterized? It has been hypothesized that the transformation is adiabatic, even though the biological conditions are nonconservative and non-rate-limited (Kugler and Turvey 1987). An adiabatic transformation requires that the rhythmic system's action (energy/frequency) and entropy production remain time-invariant throughout the transformation. The non-conservative adiabatic hypothesis was evaluated through an experiment on human rhythmic hand movements. On each trial, a subject began at a prescribed frequency and then, over a 30 s interval, increased (or decreased) the frequency continuously at will. For each subject, on each increasing and decreasing trial, cycle kinetic energy was a linear function of cycle frequency with a negative energy intercept. By the adiabatic hypothesis, the slope of the function defines the constant action and the intercept defines the constant dissipation — changes in cycle frequency incur no changes in energy dissipated per cycle. Slopes and intercepts were correlated suggesting a common basis for the two constants, and the variety of cycle amplitude-cycle duration relations were in agreement with the nonmonotonic, nonlinear space-time function predicted by the hypothesis. The possibilities of addressing aspects of the data through (a) muscle modeled as a continuum of Kelvin bodies with a continuous relaxation spectrum, and (b) various classes of autonomous differential equations, were discussed. Most importantly, the discussion focused on the puzzling independence of energy cost and speed exhibited by locomoting animals differing in morphology, physiology, size, and taxa. It was suggested that the independence may reflect a very general principle — adiabatic transformability of biological movement systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198774
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  • 10
    Electronic Resource
    Electronic Resource
    Boreal forests and tundra (1993)
    Springer
    Water, air & soil pollution 70 (1993), S. 39-53 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The circumpolar boreal biomes coverca. 2 109 ha of the northern hemisphere and containca. 800 Pg C in biomass, detritus, soil, and peat C pools. Current estimates indicate that the biomes are presently a net C sink of 0.54 Pg C yr−1. Biomass, detritus and soil of forest ecosystems (includingca. 419 Pg peat) containca. 709 Pg C and sequester an estimated 0.7 Pg C yr−1. Tundra and polar regions store 60–100 Pg C and may recently have become a net source of 0.17 Pg C yr−1. Forest product C pools, including landfill C derived from forest biomass, store less than 3 Pg C but increase by 0.06 Pg C yr−1. The mechanisms responsible for the present boreal forest net sink are believed to be continuing responses to past changes in the environment, notably recovery from the little ice-age, changes in forest disturbance regimes, and in some regions, nutrient inputs from air pollution. Even in the absence of climate change, the C sink strength will likely be reduced and the biome could switch to a C source. The transient response of terrestrial C storage to climate change over the next century will likely be accompanied by large C exchanges with the atmosphere, although the long-term (equilibrium) changes in terrestrial C storage in future vegetation complexes remains uncertain. This transient response results from the interaction of many (often non-linear) processes whose impacts on future C cycles remain poorly quantified. Only a small part of the boreal biome is directly affected by forest management and options for mitigating climate change impacts on C storage are therefore limited but the potential for accelerating the atmospheric C release are high.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01104987
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