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  • Weitere Quellen  (510)
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  • FLUID MECHANICS AND HEAT TRANSFER  (327)
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  • 1
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    Solution adaptive grid generation (1983)
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    Publikationsdatum: 2011-08-19
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 2; p 651-68
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  • 2
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    Navier-Stokes solution for quasi-three dimensional flow (1983)
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    Publikationsdatum: 2011-08-19
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 1; p 329-33
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  • 3
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    Vectorized, implicit Navier-Stokes solver for 2-D incompressible flows (1983)
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    Publikationsdatum: 2011-08-19
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 1; p 273-31
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  • 4
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    Clebsch velocity decomposition for rotational conical flows (1983)
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    Publikationsdatum: 2011-08-19
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 1; p 183-19
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  • 5
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    Influence of convection on the growth of crystals from solution (1983)
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    Publikationsdatum: 2011-08-19
    Beschreibung: This is a review of the influence of convection on the growth of crystals from solution. The growth rate is increased by convection up to the point where interface kinetics becomes rate controlling. Compositional inhomogeneity and morphological instability (inclusion formation) are probably worse for gentle convection than for either no convection or for vigorous stirring. Stirring, particularly of crystal suspensions, can cause an orders of magnitude increase in the rate of formation of new crystals. This is called 'secondary nucleation'.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Journal of Crystal Growth (ISSN 0022-0248); 65; 133-142
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  • 6
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    The effects of hypergravity on the rate of antibody formation in the rat (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: This experiment was designed to measure the immune response in acutely stressed and chronically centrifuged hyper-G-adapted male rats. Rats were exposed to 2.1 and 3.1 G. Acutely stressed animals were injected with sheep red blood cells (SRBC) on the day of inital exposure to hyper-G, and were chronically centrifuged for 10 to 15 days after immunization. Hyper-G-adapted rats were chronically centrifuged for 28 days prior to antigen injection and for 21 days after injection. Booster injections were given and serum samples taken at intervals from 3 to 9 days after the initial and booster injections. Antigen dose, injected ip, ranged between 1.35 x 10 to the 6th and 1.38 x 10 to the 9th SRBC/100 g. body weight. Pair-fed and ad libitum fed noncentrifuged controls were used. No significant differences in anti-SRBC antibody titers were found between centrifuged and control animals, although there were some changes in WBC counts and a significant increase in adrenal-gland size in acutely stressed animals.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Physiologist, Supplement (ISSN 0031-9376); 26; S-135
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  • 7
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    The effects of immobilization on cortical bone in monkeys (M. nemestrina) (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Rhesus and pigtail monkeys were restrained for up to seven months in a hypogravic-hypodynamic environment for the purpose of studying the osteoporotic process and its reversibility, particularly in relation to humans. In vivo bending, radiography and tomography are among the techniques that were used. Bone deterioration within one month was detectable only in histological preparation, where resorption and subsequent cavity formation were demonstrated in addition to demineralization of the remaining hard tissue. Norland bone mineral analysis showed the greatest bone demineralization in the proximal tibia (23 percent to 31 percent after six months restraint), recovery did not even necessarily occur after 15 months. The largest bone stiffness decrease was 36 to 40 percent after a six months restraint; normal bending properties but not mineral content were restored after 8-1/2 months. Contrary to earlier studies, it is concluded that bone recovery, though a lengthy process, is possible: cortical bone in the tibia required 40 months.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Physiologist, Supplement (ISSN 0031-9376); 26; S-115
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  • 8
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    The production of turbulent stress in a shear flow by irrotational fluctuations (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Attention is given to the way in which external turbulence affects an initially turbulence-free region in which there is a mean velocity gradient. External turbulence induces irrotational fluctuations in the sheared region which interact with the shear to produce rotational velocity fluctuations and mean Reynolds stresses. Since the actual front between the initial external turbulence and the shear flow is a randomly contorted surface, the turbulence near the front is intermittent, and is presently included in the form of a simple statistical model. In wind tunnel tests, turbulent shear stress was found to grow from zero to significant values in the interaction region. Observed stress magnitude and extent agrees with predictions, and it is concluded that turbulent stresses can be produced by irrotational fluctuations in a region of mean shear.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Journal of Fluid Mechanics (ISSN 0022-1120); 137; 307-329
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  • 9
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    Viscous thermocapillary convection at high Marangoni number (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: A liquid, contained in a quarter plane, undergoes steady motion due to thermocapillary forcing on its upper boundary, a free surface separating the liquid from a passive gas. The rigid vertical sidewall has a strip whose temperature is elevated compared with the liquid at infinity. A boudnary-layer analysis is performed that is valid for large Marangoni numbers M and Prandtl numbers P. It is found that the Nusselt number N for the horizontal heat transport satisfies N proportional to min (M to the 1 2/7/power, M to the 1 1/5/power, M to the 1 1/10/power) Generalizations are discussed.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Journal of Fluid Mechanics (ISSN 0022-1120); 135; 175-188
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  • 10
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    On the evolutionary constraint surface of hydra (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Food consumption, body size, and budding rate were measured simultaneously in isolated individual hydra of six strains. For each individual hydra the three measurements define a point in the three dimensional space with axes: food consumption, budding rate, and body size. These points lie on a single surface, regardless of species. Floating rate and incidence of sexuality map onto this surface. It is suggested that this surface is an example of a general class of evolutionary constraint surfaces derived from the conjunction of evolutinary theory and the theory of ecological resource budgets. These constraint surfaces correspond to microevolutionary domains.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Biological Bulletin (ISSN 0006-3185); 165; 305-320
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  • 11
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    Stagnation-point ablation of carbonaceous flat disks. II Experiment (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Six flat-disk models made of carbon-carbon and carbon-phenolic materials were launched in an argon-filled track-range facility to test ablation characteristics in a radiation-dominated, massive-blowing environment. The shock standoff distances deduced from the shadowgraphs agree with theoretical predictions during the earlier portion of the flight, while the wall temperatures determined by the image-converter photographs agree with predictions during the later portion. The measured surface recessions exceed the calculated values by about 60 percent for carbon-phenolic and 30 percent for carbon-carbon. The discrepancies are attributed to spallation. The measured char thicknesses agree with theoretical predictions.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: AIAA Journal (ISSN 0001-1452); 21; 1748-175
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  • 12
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    Continuation in a parameter - Experience with viscous and free surface flows (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The results of modifications in continuation methods applied to obtain solutions to the Navier-Stokes systems of equations for incompressible, two-dimensional, steady flows are reported. It is shown that parameter continuation permits prediction of accurate, initial estimates for iterative processing of nonlinear finite difference and finite element equations of motions. The new parameter steps are derived from values of the preceding parameter steps. The accuracy of the estimates is ensured with appropriate choices of the step size. The continuation predictor/iterative corrector is demonstrated to trace the branches of parameter space along which steady flow states are found, and techniques are available for tracing multiply branching paths. The techniques are applied to solving the Navier-Stokes equations for flow through a rotating square channel, the formation of a falling liquid curtain, and gyrostatic equilibria of rotating cylindrical drops.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
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  • 13
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    Modeling of transient two-component flow using a four-point implicit method (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The four-point, centered implicit scheme that is extensively used in open channel flow simulation is shown to be applicable to rapid and slow pressure transient problems in conduits with nearly single phase and two-phase flows. It is only necessary to choose the proper weighting factor value, theta, of the Courant number. For rapid pressure transients such as waterhammer, the implicit method can yield reasonable results with limited numerical dispersion and attenuation if theta is only slightly greater than the critical value of 0.5. For slower pressure gradients in single and two-phase flows, reasonable numerical solutions may be achieved for Courant number values as high as 20.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
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  • 14
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    The production of turbulent stress in a shear flow by irrotational fluctuations (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: This paper examines, both theoretically and experimentally, the effect produced by irrotational fluctuations, associated with a nearby turbulent field, in a region where the turbulence is initially very low but where there is a mean shear. Calculations are based on rapid distortion theory and experiments use linearized hot wire anemometers in an open circuit wind tunnel. Turbulent shear stress is observed to grow from zero to significant values in the interaction region. The magnitude and extent of this observed shear stress agree reasonably well with predictions of the analysis, when intermittency effects are included. It is concluded that turbulent stresses can be produced by irrotational fluctuations in a region of mean shear and that this effect can be estimated using rapid distortion theory if the overall strain ratio is not large.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
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  • 15
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    A modified Dodge algorithm for the parabolized Navier-Stokes equations and compressible duct flows (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: A revised version of Dodge's split-velocity method for numerical calculation of compressible duct flow was developed. The revision incorporates balancing of mass flow rates on each marching step in order to maintain front-to-back continuity during the calculation. The (checkerboard) zebra algorithm is applied to solution of the three dimensional continuity equation in conservative form. A second-order A-stable linear multistep method is employed in effecting a marching solution of the parabolized momentum equations. A checkerboard iteration is used to solve the resulting implicit nonlinear systems of finite-difference equations which govern stepwise transition. Qualitative agreement with analytical predictions and experimental results was obtained for some flows with well-known solutions. Previously announced in STAR as N82-16363
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: International Journal for Numerical Methods in Fluids (ISSN 0271-2091); 3; 493-506
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  • 16
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    Accuracy of approximations to the Navier-Stokes equations (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The systems of truncated differential equations that have been proposed to reduce the complexity and large computational costs of solutions to the full Navier-Stokes equations are considered. These systems are computationally efficient and capture all the physically relevant behavior. The systems follow a certain hierarchy: (1) the classical boundary-layer equations with specified edge properties (usually the streamwise pressure distribution); (2) the coupled boundary-layer/inviscid equations; (3) the so-called thin-layer equations that discard streamwise diffusion; and (4) the Navier-Stokes equations. Consideration is given to each of these approximations applied to an incompressible, laminar-separating flow at low and moderate Reynolds numbers. It is pointed out that for any flow or region of flow for which viscous-inviscid interaction effects are small, classical boundary-layer equations will provide a satisfactory description of the viscous flow at a fraction of the computational cost of any higher approximations.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: AIAA Journal (ISSN 0001-1452); 21; 1759
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  • 17
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    Growth of Goertler vortices in compressible boundary layers along curved surfaces (1983)
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    Publikationsdatum: 2011-08-19
    Beschreibung: An investigation of the growth of the three-dimensional, counter-rotating, longitudinal type vortices is considered in two-dimensional laminar compressible boundary-layer flow. The basic approximation of the disturbance equations that includes the terms due to boundary layer growth is considered and solved numerically. These terms are shown to have large local effects near the neutral stability region. The study shows that the instability of the boundary layer with respect to the three-dimensional vortices sets in at higher Goertler number as Mach number increases. Also the maximum amplitude ratio of the vortices is reduced by about 20 percent as Mach number increases from 0 to 5.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Journal of Engineering and Applied Sciences (ISSN 0191-9539); 2; 3, 19; 213-238
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  • 18
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    The significance of gravity on biological systems (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Ground based and spaceborne (Biosatellite) research into the effects of hypogravity on biological systems is summarized. A concept of sensitivity to gravity is defined: sensitivity = dR/dQ x 1/standard deviation of R, where R is the measured biological response to a quantitative stimulus, Q. Detection and transformation of gravity information by the organism are discussed. The role of an uncommon gravity force environment as stimulus for physiologic adaptations, rather than stress, is introduced.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: ESA Space Biol. with Emphasis on Cell and Develop. Biol.; p 3-9
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  • 19
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    Finite element calculation of buoyancy-driven convection near a melt/solid phase boundary (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Two iterative schemes based on the mixed finite element method are developed for analyzing steady natural convection in a melt adjacent to its solid phase. The simplest method decouples the calculation of the field variables and the shape of the melt/solid interface into two interlocked iterations that are performed successively. The second method uses Newton's iteration to solve simultaneously for both types of unknowns and has a quadratic convergence rate. Results for a model problem of melt and solid in a cylindrical ampoule show the Newton algorithm to be a factor of three more efficient.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
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  • 20
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    Neural mechanisms of motion sickness (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The possibility that there might be a neuro-homoral cerebrospinal fluid link in motion sickness was directly tested by blocking the flow of CSF from the third into the fourth ventricle in cats. Evidence obtained thus far is consistent with the hypothesis. Cats with demonstrably sound plugs did not vomit in response to an accelerative motion sickness stimulus, whereas cats with imperfect 'leaky' plugs vomited with little or no delay in latency. Althoough there are several putative candidates, the identification of a humoral motion sickness substance is a matter of conjecture.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
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  • 21
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    Fine-structural changes in the midgut of old Drosophila melanogaster (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Senescent fine-structural changes in the midgut of Drosophila melanogaster are investigated. A large number of midgut mitochondria in old flies exhibit nodular cristae and a tubular system located perpendicular to the normal cristae orientation. Anterior intestinal cells show a senescent accumulation of age pigment, either with a surrounding two-unit membrane or without any membrane. The predominant localization of enlarged mitochondria and pigment in the luminal gut region may be related to the polarized metabolism of the intestinal cells. Findings concur with previous observations of dense-body accumulations and support the theory that mitochondria are involved in the aging of fixed post-mitotic cells. Demonstrated by statistical analyses is that mitochondrial size increase is related to mitochondrial variation increase.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Mechanisms of Ageing and Development (ISSN 0047-6374); 23; 265-276
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  • 22
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    Glucocorticoid sensitivity, disuse, and the regulation of muscle mass (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: A new noninvasive immobilization procedure to be used on rats has been developed to study immobilization-induced muscle hypersensitivity to normal glucocorticoid concentration, subsequent muscle atrophy, and atrophy recovery. The immobilization procedure involves encasing the hind limb in a light-weight plasticlike cast (10 percent the usual plaster weight), completely resistant to animal gnawing. The effects of right-angle immobilization of the ankle on the slow fiber soleus, and the fast fiber extensor digitorum longus, resemble the effects of weightlessness. The increased concentration of glucocorticoid receptor sites in immobilized and denervated muscle is discussed, along with the chronic loss of muscle mass that occurs in practically all dystrophies. It is concluded that lack of mechanical work in a zero gravity environment is a major cause of glucocorticoid hypersensitivity in the body's musculature.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Physiologist, Supplement (ISSN 0031-9376); 26; S-92
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  • 23
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    Hyperthermic effects of centrally injected (D-ALA2, N-ME-PHE4, MET-(0)5-OL)-enkephalin (FK 33-824) in rabbits and guinea-pigs (1983)
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    Publikationsdatum: 2011-08-18
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Neuropharmacology (ISSN 0028-3908); 22; 10, 1
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  • 24
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    Multiple-grid convergence acceleration of viscous and inviscid flow computations (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: A multiple-grid algorithm for use in efficiently obtaining steady solution to the Euler and Navier-Stokes equations is presented. The convergence of a simple, explicit fine-grid solution procedure is accelerated on a sequence of successively coarser grids by a coarse-grid information propagation method which rapidly eliminates transients from the computational domain. This use of multiple-gridding to increase the convergence rate results is substantially reduced work requirements for the numerical solution of a wide range of flow problems. Computational results are presented for subsonic and transonic inviscid flows and for laminar and turbulent, attached and separated, subsonic viscous flows. Work reduction factors as large as eight, in comparison to the basic fine-grid algorithm, were obtained. Possibilities for further performance improvement are discussed. Previously announced in STAR as N83-21847
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Applied Mathematics and Computation (ISSN 0096-3003); 13; 375-398
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  • 25
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    Metabolic alkalosis during immobilization in monkeys (M. nemestrina) (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The systemic and renal acid-base response of monkeys during ten weeks of immobilization was studied. By three weeks of immobilization, arterial pH and bicarbonate concentrations were elevated (chronic metabolic alkalosis). Net urinary acid excretion increased in immobilized animals. Urinary bicarbonate excretion decreased during the first three weeks of immobilization, and then returned to control levels. Sustained increases in urinary ammonium excretion were seen throughout the time duration of immobilization. Neither potassium depletion nor hypokalemia was observed. Most parameters returned promptly to the normal range during the first week of recovery. Factors tentatively associated with changes in acid-base status of monkeys include contraction of extracellular fluid volume, retention of bicarbonate, increased acid excretion, and possible participation of extrarenal buffers.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Calcified Tissue International (ISSN 0008-0594); 35; 472-476
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  • 26
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    Effect of confinement in small space flight size cages on insulin sensitivity of exercise-trained rats (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The effect of confinement in small cages (simulating the size to be used in future space Shuttle missions) on insulin sensitivity was studied in rats having an increased insulin sensitivity due to exercise training prior to confinement. Oral glucose tolerance tests (OGTT) were given to both control and exercise-trained rats before and after placement in the small cages for 7 days. The insulin resistance was assessed by the product of the area of the insulin and glucose curves of the OGTT (IG index). Results show that the values obtained before confinement were one-half as high in exercise-trained rats as those in control rats, reflecting an increased sensitivity to insulin with exercise training. After 7 days confinement, the IG index was found to be not significantly different from initial values for both control and exercise-trained rats. These findings suggest that increased insulin sensitivity in exercise-trained rats persists 7 days after cessation of running activity. The data also indicate that exercise training, before flight, may be beneficial in minimizing the loss of insulin sensitivity expected with decreased use of gravity dependent muscles during exposure to hypogravity in space flight.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Aviation, Space and Environmental Medicine (ISSN 0095-0562); 54; Oct. 198
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  • 27
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    Rapid purification of fluorescent enzymes by ultrafiltration (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: In order to expedite the preparation of fluorescently tagged enzymes for histo-cyctochemistry, a previously developed method employing gel column purification was compared with a more rapid modern technique using the Millipore Immersible CX-ultrafilter. Microscopic evaluation of the resulting conjugates showed comparable products. Much time and effort is saved using the new technique.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Preparative Biochemistry (ISSN 0032-7484); 13; 1, 19; 1983
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  • 28
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    Removal of histological sections from glass for electron microscopy - Use of Quetol 651 resin and heat (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: A number of approaches have been used to separate stained conventional histological sections from glass slides in preparation for a study with the electron microscope. However, in each reported case some problems were encountered with respect to the separation process. The present investigation is concerned with the use of the epoxy resin Quetol 651 as an embedding medium for this procedure, taking into account the simple application of heat (62-64 C) for performing the separation step. After the tissue has been removed from the glass by the considered technique, it is thin sectioned, and stained with uranyl acetate-lead citrate.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Stain Technology (ISSN 0038-9153); 58; 1, 19; 1983
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  • 29
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    Effect of variable thermal conductivity on isotherms in Bridgman growth (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: A change in thermal conductivity associated with melting or solidification can have a profound influence on the isotherms near the solidification interface if the material is being directionally solidified in an ampoule whose walls carry a substantial portion of the heat. This analysis was prompted by a recent discovery that the thermal conductivity of Hg(1-x)CD(x)Te increased dramatically as the material is heated above the solidus curve. An illustrative example is shown in which the sample is approximated as an infinite cylinder with constant but diffferent thermal properties in the solid and melt. The boundary conditions are fixed on the surface by a conductive ampoule in a two-zone Bridgman furnace with an adiabatic region separating the two zones. The effect of the adiabatic zone in this case is to intensify the curvature of the interface rather than to lessen it.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Journal of Crystal Growth (ISSN 0022-0248); 61; Apr
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  • 30
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    Effect of spaceflight on the non-weight-bearing bones of rat skeleton (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The effects of weightlessness on the integrated growth and remodeling of nonweight-bearing bones (the mandibles, teeth, and ribs) were studied. Rats prelabeled with tetracycline to mark the surfaces of bone and tooth formation were subjected to spaceflight conditions for 18.5 days, followed by further injections of tetracycline on days 6 and 29 postflight.Results show that spaceflight conditions did not alter the rate of periosteal bone formation in the ribs and regions of the mandibles covered by masticatory muscles, although bone formation-calcification rates were found to be impaired at those sites in the jaw that had no contiguous muscle (molar region). The remodeling activity on the alveolar bone around the buccal roots of the molar teeth was found to be significantly reduced. While total Ca, P, and hydroxyproline concentrations in the jaws, incisors, and ribs were normal after spaceflight, it was determined that weightless conditions caused a delay in the maturation of bone mineral and matrix in the jaws. These anomalies were found to be corrected by 29 days postflight. These results indicate that most of the nonweight-bearing bones of the rat skeleton are at risk to the effects of weightlessness.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: American Journal of Physiology; Regulatory, Interactive and Comparative Physiology (ISSN 0363-6119); 13; March 19
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  • 31
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    Removal of histological sections from glass for electron microscopy - Use of Quetol 651 resin and heat (1983)
    In:  Other Sources
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    Publikationsdatum: 2011-08-18
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Stain Technology (ISSN 0038-9153); 58; 1, 19; 1983
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  • 32
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    Settling of fixed erythrocyte suspension droplets (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: It is pointed out that when particles behave collectively rather than individually, the fractionation of micron-size particles on the basis of size, density, and surface characteristics by centrifugation and electrophoresis is hindered. The formation and sedimentation of droplets containing particles represent an extreme example of collective behavior and pose a major problem for these separation methods when large quantities of particles need to be fractionated. Experiments are described that measure droplet sizes and settling rates for a variety of particles and droplets. Expressions relating the particle concentration in a drop to measurable quantities of the fluids and particles are developed. The number of particles in each droplet is then estimated, together with the effective droplet density. Red blood cells from different animals fixed in glutaraldehyde provide model particle groups.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Biorheology (ISSN 0006-355X); 20; 2, 19; 1983
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  • 33
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    Analysis of coolant entrance boundary shape of porous region to control cooling along exit boundary (1983)
    In:  Other Sources
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    Publikationsdatum: 2011-08-18
    Beschreibung: A cooled porous region has a plane surface exposed to a specified spatially varying heat flux. The coolant leaves the region through this surface, and it is desired to control the flow distribution to maintain a specified uniform surface temperature. This is accomplished by having the coolant entrance surface shaped to provide in the region the necessary variation of path length and, hence, flow resistance. The surface shape at the coolant entrance is found by solving a Cauchy boundary value problem. An exact solution is obtained that will deal with a wide variety of heating distributions for both two- and three-dimensional shapes.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: ASME, Transactions, Journal of Heat Transfer (ISSN 0022-1481); 105; Aug. 198
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  • 34
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    Tibial changes in experimental disuse osteoporosis in the monkey (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The mechanical properties and structural changes in the monkey tibia with disuse osteoporosis and during subsequent recovery are investigated. Bone mending stiffness is evaluated in relation to microscopic changes in cortical bone and Norland bone mineral analysis. Restraint in the semireclined position is found to produce regional losses of bone most obviously in the anterior-proximal tibiae. After six months of restraint, the greatest losses of bone mineral in the proximal tibiae range from 23 percent to 31 percent; the largest changes in bone stiffness range from 36 percent to 40 percent. Approximately eight and one-half months of recovery are required to restore the normal bending properties. Even after 15 months of recovery, however, the bone mineral content does not necessarily return to normal levels. Histologically, resorption cavities in cortical bone are seen within one month of restraint; by two and one-half months of restraint there are large resorption cavities subperiosteally, endosteally, and intracortically. After 15 months of recovery, the cortex consists mainly of first-generation haversian systems. After 40 months, the cortex appears normal, with numerous secondary and tertiary generations of haversian systems.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Calcified Tissue International (ISSN 0008-0594); 35; 1983
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  • 35
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    Peptide and non-peptide opioid-induced hyperthermia in rabbits (1983)
    In:  Other Sources
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    Publikationsdatum: 2011-08-18
    Beschreibung: The intracerebroventricular administration of prototype nonpeptide opioid receptor (mu, kappa, and sigma) agonists, morphine, ketocyclazocine, and N-allyl-normetazocine was found to induce hyperthermia in rabbits. The similar administration of peptide opioids like beta-endorphin (BE), methionine-enkephalin (ME), and its synthetic analogue D-ala2-methionine-enkephalinamide (DAME) was also found to cause hyperthermia. Results indicate that only the liver-like transport system is important to the ventricular inactivation of BE and DAME. Prostaglandins and norepinephrine were determined not to be involved in peptide and nonpeptide opioid-induced hyperthermia. In addition, cAMP was not required since a phosphodiesterase inhibitor, theophylline, did not accentuate the hyperthermia due to peptide and nonpeptide opioids. Naloxone-sensitive receptors were found to be involved in the induction of hyperthermia by morphine, BE, ME, and DAME since naloxone attenuated them. However, the hyperthermic response to ketocyclazocine and N-allyl-normetazocine was not antagonized by naloxone.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Brain Research (ISSN 0006-8993); 265; 1983
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  • 36
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    Numerical solutions for spin-up from rest in a cylinder (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: A set of three-dimensional flow-field data for the region around a cylinder impulsively spun-up from rest was derived with a numerical model based on the Navier-Stokes equations. Laser-Doppler anemometer data in the azimuthal direction was employed to test the model predictions, and data was developed for a flowfield with Ekman numbers from 9.18/1,000,000 to 9.18/10,000. The contributions of inviscid and viscous terms were determined as functions of radius and time. It was found that immediately after start-up viscous diffusion is the dominant factor, which is replaced by nonlinear radial advection. The Coriolis force dominates in the later stages of spin-up. The inward radial flow is a maximum near the front, where the vertical velocity is small, but features strong radial gradients, as it does at the edge of the Ekman layer.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Journal of Fluid Mechanics; 127; Feb. 198
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    Stabilization of the yeast desaturase system by low levels of oxygen (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The stability of particulate palmitoyl-CoA desaturase preparations from anaerobically grown yeast cells was increased by exposure to low levels of oxygen. The stabilizing effect of oxygen may be based upon the increased amounts of palmitoleic acid and ergosterol that become available to the cells. These results suggest the evolutinary appearance of this system at a time when atmospheric oxygen was at a low level.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Origins of Life (ISSN 0302-1688); 13; March 19
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  • 38
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    Role of metabolic rate and DNA-repair in Drosophila aging Implications for the mitochondrial mutation theory of aging (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The notion that injury to mitochondrial DNA is a cause of intrinsic aging was tested by correlating the different respiration rates of several wild strains of Drosophila melanogaster with the life-spans. Respiration rate and aging in a mutant of D. melanogaster deficient in postreplication repair were also investigated. In agreement with the rate of living theory, there was an inverse relation between oxygen consumption and median life-span in flies having normal DNA repair. The mutant showed an abnormally low life-span as compared to the controls and also exhibited significant deficiency in mating fitness and a depressed metabolic rate. Therefore, the short life-span of the mutant may be due to the congenital condition rather than to accelerated aging.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Experimental Gerontology (ISSN 0531-5565); 18; 1983
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  • 39
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    Procedure for generating ground wind environments for Shuttle liftoff studies (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Ground-wind environments for Monte Carlo simulations of Space Shuttle liftoff at KSC are developed. Input parameters include randomly selected 18.3-m-altitude peak wind speed (from which mean wind profile and turbulence intensity are calculated), randomly selected mean wind direction, and longitudinal and lateral turbulence components obtained from the Shuttle-simulation turbulence tapes (SSTT: Tatom et al., 1982). The steps in the simulation of turbulence time histories and horizontal wind fields are listed. It is found that separate statistical analysis of each hour-season pair, applying data on the time fraction of occurrence of peak winds and wind directions at KSC, will be necessary to interpret simulation results consistently.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Journal of Spacecraft and Rockets (ISSN 0022-4560); 20; July-Aug
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  • 40
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    The evolution of Tollmien-Schlichting waves near a leading edge (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The method of matched asymptotic expansions is used to study the generation of Tollmien-Schlichting waves by free-stream disturbances incident on a flat-plate boundary layer. Near the leading edge, the motion is governed by the unsteady boundary-layer equation, while farther downstream it is governed (to lowest order) by the Orr-Sommerfeld equation with slowly varying coefficients. It is shown that there is an overlap domain where the Tollmien-Schlichting wave solutions to the Orr-Sommerfeld equation and appropriate asymptotic solutions of the unsteady boundary-layer equation match, in the matched-asymptotic-expansion sense. The analysis explains how long-wavelength free-stream disturbances can generate Tollmien-Schlichting waves of much shorter wavelength. It also leads to a set of scaling laws for the asymptotic structure of the unsteady boundary layer.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Journal of Fluid Mechanics; 127; Feb. 198
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  • 41
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    Comparative effect of lunar fines and terrestrtrial ash on the growth of a blue-green alga and germinating radish seeds (1983)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: Although it is understood that photosynthetic organisms will be required as components of a closed ecological life support system (CELSS) for a manned lunar based, a basic problem is to identify organisms best capable of utilizing lunar regolith materials. Also, there is need to determine what nutrient supplements have to be added to lunar soils, and at what levels in order to promote high bio-mass production.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: NASA. Johnson (Lydon B.) Space Center The 1983 NASA/ASEE Summer Faculty Fellowship Research Program Research Reports; NASA. Johnson (Lydo
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  • 42
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    Sparger system for MMH-helium vents (1983)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: Based on a calculated vent flow rate and MMH concentration, a TI-59 program was run to determine total sparger hole area for a given sparger inlet pressure. Hole diameter is determined from a mass transfer analysis in the holding tank to achieve complete capture of MMH. In addition, based on oxidation kinetics and vapor pressure data, MMh atmospheric concentrations are determined 2 ft above the holding tank.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: The 1983 NASA(ASEE Summer Faculty Fellowship Research Program Research Reports; 17 p
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  • 43
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    An analysis of cryotrap heat exchanger performance test data (400 area) and recommendations for a system to handle Apollo RCS engines (1983)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: The current arrangement of a Platecoil heat exchanger which uses LN2 on the inside of parallel tubes, in counter flow to the test cell engine exhaust gases which are drawn through a box surrounding the plates by the existing vacuum blowers is examined. As a result of inadequate performance and special test data it was decided to redesign the system to accommodate an Apollo RCS engine.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: The 1983 NASA(ASEE Summer Faculty Fellowship Research Program Research Reports; 15 p
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  • 44
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    Interaction between Escherichia coli and lunar fines (1983)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: A sample of mature lunar fines (10084.151) was solubilized to a high degree (about 17 percent) by the chelating agent salicylic acid (0.01. M). The neutralized (pH adjusted to 7.0) leachate was found to inhibit the growth of Escherichia coli (ATCC 259922) in a minimial mineral salts glucose medium; however, the inhibition was somewhat less than that caused by neutralized salicylic acid alone. The presence of lunar fines in the minimal medium was highly stimulatory to growth of E. coli following an early inhibitory response. The bacterium survived less well in the lunar leachate than in distilled water, no doubt because of the salicylate. It was concluded that the sample of lunar soil tested has nutritional value to E. coli and that certain products of fermentation helped to solubilize the lunar soil.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: NASA. Johnson (Lyndon B.) Space Center The 1983 NASA/ASEE Summer Faculty Fellowship Research Program Research Reports; NASA. Johnson (Lynd
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  • 45
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    The scanning electron microscope as a tool in space biology (1983)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: Normal erythrocytes are disc-shaped and are referred to here descriptively as discocytes. Several morphologically variant forms occur nomally but in rather small amounts, usually less than one percent of total. It has been shown though, that spiculed variant forms referred to as echinocytes are generated in significant amounts at zero g. Normal red cells have been stressed in vitro in an effort to duplicate the observed discocyte-echinocyte transformation at zero g. The significance of this transformation to extended stay in space and some of the plausible reasons for this transformation are discussed.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: NASA. Johnson (Lyndon B.) Space Center The 1983 NASA/ASEE Summer Faculty Fellowship Research Program Research Reports; NASA. Johnson (Lynd
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  • 46
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    Jet array impingement heat transfer characteristics (1983)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: Two dimensional arrays of circular air jets impinging on a heat transfer surface parallel to the jet orifice plate are considered. The jet flow, after impingement, is constrained to exit in a single direction along the channel formed by the jet orifice plate and the heat transfer surface. In addition to the crossflow which originates from the jets following impingement, an initial crossflow is present which approaches the array through an upstream extension of the channel. The configurations considered are intended to model the impingement cooled midchord region of gas turbine airfoils in cases where an initial crossflow is also present. A major objective is determination of the effect of initial crossflow air temperature relative to jet array air temperature on impingement surface heat fluxes.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: NASA. Lewis Research Center Turbine Eng. Hot Sect. Technol. (HOST); p 117-128
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  • 47
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    Coolant passage heat transfer with rotation. A progress report on the computational aspects (1983)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: Turbine airfoils are subjected to increasingly higher heat loads which escalate the cooling requirements in order to satisfy life goals for the component materials. If turbine efficiency is to be maintained, however, cooling requirements should be as low as possible. To keep the quantity of cooling air bounded, a more efficient internal cooling scheme must be developed. One approach is to employ airfoils with multipass cooling passages that contain devices to augment internal heat transfer while limiting pressure drop. Design experience with multipass cooling passage airfoils has shown that a surplus of cooling air must be provided as a margin of safety. This increased cooling air leads to a performance penalty. Reliable methods for predicting the internal thermal and aerodynamic performance of multipass cooling passage airfoils would reduce or eliminate the need for the safety margin of surplus cooling air. The objective of the program is to develop and verify improved analytical methods that will form the basis for design technology which will result in efficient turbine components with improved durability without sacrificing performance. The objective will be met by: (1) establishing a comprehensive experimental data base that can form the basis of an empirical design system; (2) developing computational fluid dynamic techniques; and (3) analyzing the information in the data base with both phenomenological modeling and mathematical modeling to derive a suitable design and analysis procedure.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: NASA. Lewis Research Center Turbine Eng. Hot Sect. Technol. (HOST); p 111-116
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  • 48
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    Calcium Ions, Stores, and Modulators: What Is the Gravity Receptor Connection? (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-10
    Beschreibung: The effect of weightlessness on gravireceptors is considered in an effort to shed light on the etiology of space motion sickness. The structures of the gravireceptors (crystals and neuroepithelium) are examined to determine the role piezoelectricity plays.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 147-164
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  • 49
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    The Plasma Membrane Calcium Pump (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-10
    Beschreibung: Three aspect of cellular calcium metabolism in animal cells was discussed including the importance of the plasma membrane in calcium homeostasis, experiments dealing with the actual mechanism of the calcium pump, and the function of the pump in relationship to the mitochondria and to the function of calmodulin in the intact cell.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 165-179
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    Measurement and Control of Free Calcium Inside Small Intact Cells (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-10
    Beschreibung: The use of dye to measure intracellular free calcium concentration was discussed. Difficulty in measuring the calcium is caused by two problems: the small amount of calcium available for testing, and the selectivity to bind calcium at 100 nanomolar excludes substances from entering the cell.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 200-217
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    Role of Calmodulin in Cell Proliferation (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-10
    Beschreibung: Calmodulin levels were found to increase as cells enter plateau. The data suggest that the cells are exiting the cell cycle late in the G sub 1 phase, or that the calmodulin levels in plateau cells are uncoupled to progression into S phase in plateau cells. Upon release, calmodulin levels rapidly decrease. Following this decrease, there is a increase prior to S phase.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 218-232
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    Polarity of the Amphibian Egg (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-10
    Beschreibung: Amphibian egg polarity and the mechanism which generates the polarity is addressed. Of particular concern is the question of whether the activation rotation which responds to gravity is a prerequisite for normal development.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 133-141
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    A Study of Accretion in Compact Sources: Disk Precession and Jet Helicity (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-11
    Beschreibung: The effect of adiabatic expansion on the propagation and growth of helical twisting on a supersonic jet is investigated. Cooling of the jet material increases the jet's Mach number and increases the jet's density relative to that of the external medium. This has the effect of decreasing the maximum rate of growth and increasing the maximally unstable wavelength relative to the jet's radius. Propagation effects cause the wavelength of helical waves to change at a rate different from that of the maximally unstable wavelength with the result that the characteristic wavelength of helical twisting is not equal to this wavelength. The most rapidly growing helical wave will have a wavelength as much as a factor of 2 different from the instantaneous maximally unstable wavelength.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Res. Rept.: 1983 NASA(ASEE Summer Faculty Fellowship Program; 39 p
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    A Preliminary Survey of Plankton and Periphyton in the Turn Barge Canal and Basin Area of Kennedy Space Center, Florida (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-11
    Beschreibung: While thirty-seven species of various groups of organisms were identified at the five stations at KSC, further sampling is needed to further enumerate and identify phytoplankton and periphyton for the long term monitoring program and assessment for a probable polygeneration site. Thallophyta, Cyanophyta coccoid and Chrysophyta pennate were the dominant organisms. Chlorobium was the most abundant Thallophyta. Pennate diatoms were larger and more abundant at station one. The absence of Skeletonema costatum was surprising. Stations four and five appear to be acid marsh swales. Rhabdoderma lineare, a Cyanophyta coccoid found in acid lakes, was abundant in stations four and five.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Alabama Univ. Res. Rept.: 1983 NASA(ASEE Summer Faculty Fellowship program; 26 p
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    Summary of Study Group Session Discussions (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-11
    Beschreibung: The relationship between gravitational physiology and calcium metabolism is examined. The role of gravity on the problems of bone response, low gravity environments, calcium in plants, and the potential in animal systems for alterations in nerve and muscle function as variations in extracellular calcium levels occurred are discussed. Innovative materials for experiments on interactions between calcium and gravity, experiments that could utilize ionospheres or calcium-measuring dyes, and specific gravity calcium experiments are also addressed.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 245-288
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    Controls of Intracellular Communication Mediated by Gap Junctions (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-11
    Beschreibung: Experiments were done using aequorin and no increase in aequorin luminescence during acidification adequate to uncouple cells was seen. The pH sensitivity of the conductance of the perfused membrane was essentially the same as that observed with intracellular pH microelectrodes.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 233-244
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    Local Calcium Entry and the Guidance of Growth (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-11
    Beschreibung: The role of calcium in developing cells is illustrated. The Fucus egg, a brown algae is used to describe this phenomenom. Results of local calcium entry and forced calcium entry into the eggs are given.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 69-82
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    Role of Calcium and Calmodulin in Plant Cell Regulation (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-11
    Beschreibung: The role of calcium and calmodulin in plant cell regulation is discussed. Experiments are done to discover the level of calcium in plants and animals. The effect of intracellular calcium on photosynthesis is discussed.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 57-68
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    Intracellular Calcium Receptors: Calmodulin and Related Proteins (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-11
    Beschreibung: Studies on intracellular calcium receptors, calmodulin and related proteins were carried out. Calcium binding proteins, like calmodulin fall into a class of proteins that are predominantly intracellular and reversibly bind calcium with dissociation constants in the micromolar to nanomolar range. Calcium regulation of these proteins appears to be due to localized increases in calcium concentrations in the cytoplasm. The main thrust of the research is concerned with purifying and characterizing the calcium receptors and trying to elucidate mechanistically how they are involved in cellular responses.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 44-56
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    Calcium Modulation of Plant Plasma Membrane-Bound Atpase Activities (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-11
    Beschreibung: The kinetic properties of barley enzyme are discussed and compared with those of other plants. Possibilities for calcium transport in the plasma membrane by proton pump and ATPase-dependent calcium pumps are explored. Topics covered include the ph phase of the enzyme; high affinity of barley for calcium; temperature dependence, activation enthalpy, and the types of ATPase catalytic sites. Attention is given to lipids which are both screened and bound by calcium. Studies show that barley has a calmodulin activated ATPase that is found in the presence of magnesium and calcium.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 28-43
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    Calcium and Mitosis (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-11
    Beschreibung: Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 14-27
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    Gravitational Study of the Central Nervous System (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-10
    Beschreibung: A series of experiments conducted at 1G are discussed with reference to the role of calcium ions in information processing by the central nervous system. A technique is described which allows thin sections of a mammalian hippocampus to be isolated while maintaining neural activity. Two experiments carried out in hypergravic fields are also addressed; one investigating altered stimulation in the auditory system, the other determining temperature regulation responses in hypergravic fields.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 127-132
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    A Numerical Investigation of the Multiple Vortex Phenomenon: Vortex Number and Structure as a Function of Swirl Ratio (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-12
    Beschreibung: A numerical investigation of the multiple vortex phenomenon (MVP) for tornado like flows is conducted to determine the conditions for when a vortex becomes unstable and divides into smaller subsidiary vortices, as well as to determine the structure of these vortices. A three dimensional numerical model developed by Rotunno (1983) is utilized which has been demonstrated to successfully simulate MVP with properties observed both in natural as well as laboratory tornado like vortices. The MVP is generated for several swirl ratio conditions in order to determine the number of vortices generated for those flow configurations. These results are then compared to experimental measurements to validate the numerical model. The number of vortices produced is consistent with observational results made in the Purdue tornado vortex chamber. Furthermore, horizontal and vertical cross sections are taken through the vortices to determine the structure of MVP. Preliminary results indicate that tangential velocities within these smaller asymmetric vortices increase by 20% over values observed in a single axisymmetric vortex at the same swirl ratio.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Alabama Univ. Res. Rept.: 1983 NASA(ASEE Summer Faculty Fellowship Program; 28 p
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    Developing Higher Plant Systems in Space (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-10
    Beschreibung: The effects of hypogravity and microgravity environments on plant cells are discussed. Experiments on embryos of carrots are discussed. Simulation and spacecraft environments were used in experiments.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Texas Univ. The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 83-96
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    Evidence for a Regulatory Role of Calcium in Gravitropism (1983)
    In:  CASI
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    Publikationsdatum: 2014-09-10
    Beschreibung: Experiments conducted to determine the cellular basis of gravitropism, the phenomenon of calcium migration following gravitropic stimulation, and the preferential accumulation of calcium in cells are described. Results of autoradiographic studies of cross sections of oat, and the pryoantimony precipitation of calcium in situ are discussed. It was found that the movement of calcium during gravimetric stimulation is a redistribution of calcium from the vacuolar regions into the cells walls. This movement requires precipitation of a calcium ATPase. The control of calcium ATPase by calmodulin and whether chlorpromazine is binding to calmodulin in plants are considered.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: The Regulatory Functions of Calcium and the Potential Role of Calcium in Mediating Gravitational Responses in Cells and Tissues; p 2-13
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    A comparative study of time-marching and space-marching numerical methods (1983)
    In:  Other Sources
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    Publikationsdatum: 2011-08-18
    Beschreibung: Menees (1981) has conducted an evaluation of three different flowfield codes for the Jupiter entry conditions. However, a comparison of the codes has been made difficult by the fact that the three codes use different solution procedures, different computational mesh sizes, and a different convergence criterion. There are also other differences. For an objective evaluation of the different numerical solution methods employed by the codes, it would be desirable to select a simple no-blowing perfect-gas flowfield case for which the turbulent models are well established. The present investigation is concerned with the results of such a study. It is found that the choice of the numerical method is rather problem dependent. The time-marching and the space-marching method provide both comparable results if care is taken in selecting the appropriate mesh size near the body surface.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: AIAA Journal; 21; Jan. 198
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    On the structure of wall-bounded turbulent flows (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The variable-interval time-averaging (VITA) technique developed by Blackwelder and Kaplan is applied to data obtained from large-eddy simulation of turbulent channel flow in an investigation of the organized structures associated with the bursting phenomenon in the near-wall region. Conditionally averaged velocities, shear stress, pressure, and vorticity are discussed in conjunction with the bursting phenomenon detected by the VITA technique. The conditionally averaged pressure reveals that the ejection process is associated with a localized adverse pressure gradient. In the plane perpendicular to the flow direction, the conditionally averaged vorticity field indicates that a pair of counterrotating streamwise vorticity is being lifted through the ejection process. Previously announced in STAR as N83-17832.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Physics of Fluids (ISSN 0031-9171); 26; Aug. 198
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    Hyperthermic responses to central injections of some peptide and non-peptide opioids in the guinea-pig (1983)
    In:  Other Sources
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    Publikationsdatum: 2011-08-18
    Beschreibung: The intracerebroventricular administration of prototype nonpeptide opioid receptor (mu, kappa, and sigma) agonists, morphine, ketocyclazocine, and N-allyl normetazocine and an agonist at both kappa and sigma receptors, pentazocine, was found to induce hyperthermia in guinea pigs. The similar administration of peptide opioids like beta endorphin, methionine endkephalin, leucine endkephaline, and several of their synthetic analogues was also found to cause hyperthermia. Only the liver-like transport system of the three anion transport systems (iodide, hippurate, and liver-like) present in the choroid plexus was determined to be important to the central inactivation of beta-endorphin and two synthetic analogues. Prostaglandins and norepinephrine (NE) as well as cAMP were not involved in peptide and nonpeptide opioid-induced hyperthermia. Naloxone-sensitive receptors were found to be involved in the induction of hyperthermia by morphine and beta-endorphin, while hyperthermic responses to ketocyclazocine, N-allyl normetazocine, pentazocine, Met-enkephalin, Leu-enkephalin, and two of the synthetic analogues were not antagonized by nalozone. The lack of antagonism of naloxone on pyrogen, arachidonic acid, PGE2, dibutyryl cAMP, and NE-induced hyperthermia shows that endogenous opioid peptides are not likely to be central mediators of the hyperthermia induced by these agents.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Neuropharmacology (ISSN 0028-3908); 22; 5, 19; 1983
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    Coherent structures - Reality and myth (1983)
    In:  Other Sources
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    Publikationsdatum: 2011-08-18
    Beschreibung: Large-scale coherent structures (CS) in turbulent shear flows are characterized, reviewing recent theoretical and experimental investigations. The use of computers as a research tool and the flow-visualization experimental technique are introduced, CS are defined, the history of their discovery is traced, and their main characteristics are listed. Topics discussed and illustrated include the initial condition of the free shear layer, triple and double decomposition, topological features of CS, detection and eduction of CS, phase alignment via cross correlation, induced versus natural structures, the bursting phenomenon, turbulent spot, streaks, bursting frequency, the axisymmetric mixing layer, vortex pairing in an axisymmetric jet, CS and jet noise, broadband noise amplification via pure-tone excitation, CS interaction in a plane-jet near field, the Taylor hypothesis applied to CS, negative production, and the validity of the Reynolds-number similarity hypothesis. It is found that the coherent Reynolds stress, vorticity, and production are not much greater than the time-averaged values for fully developed flows with significant incoherent turbulence, suggesting that the importance of CS may have been exaggerated in some recent studies.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Physics of Fluids (ISSN 0031-9171); 26; 2816-285
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    Effects of nitric oxide and nitrogen dioxide on bacterial growth (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: While it is generally thought that the bactericidal effects of NO and NO2 derive from their reaction with water to form nitrous and nitric acids (Shank et al., 1962), this appears to be true only at high concentrations. The data presented here suggest that at low NO and NO2 concentrations, acids are not present in high enough concentrations to act as toxic agents. Reference is made to a study by Grant et al. (1979), which found that exposing acid forest soil to 1 ppm of NO2 did not cause the soil pH to drop. The results presented here show that at low concentrations of NO and NO2, the NO is bacteriostatic for some organisms and not for others, whereas NO2 may protect some bacteria from the inhibitory effects of NO. Since it has been shown that bacteria can divide while airborne (Dimmick et al., 1979), the present results suggest that NO at the low concentrations found in the atmosphere can select for resistant bacteria in the air and affect the viable airborne bacterial population.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Applied and Environmental Microbiology (ISSN 0099-2240); 198-202
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    Oxygen requirements for formation and activity of the squalene expoxidase in Saccharomyces cerevisiae (1983)
    In:  Other Sources
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    Publikationsdatum: 2011-08-18
    Beschreibung: The effect of oxygen on squalene epoxidase activity in Saccharomyces cerevisiae was investigated. In cells grown in standing cultures, the epoxidase was localized mainly in the 'mitochondrial' fraction. Upon aeration, enzyme activity increased and the newly formed enzyme was associated with the 'microsomal' fraction. At 0.03 percent (vol/vol) oxygen, epoxidase levels doubled, whereas the ergosterol level was only slightly increased. Cycloheximide inhibited the increase in epoxidase under these conditions. An apparent K sub m for oxygen of 0.38 percent (vol/vol) was determined from a crude particulate preparation for the epoxidase.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Journal of Bacteriology (ISSN 0021-9193); 488-492
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    Stagnation-point ablation of carbonaceous flat disks. I Theory (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The process of ablation is calculated for the stagnation region of a flat disk in a radiation-dominated, massive-blowing environment produced in a ballistic range filled with argon. Flow environments are determined by solving the boundary-layer equations while radiative transfer is calculated through a line-by-line spectral computation. The resulting wall heat-transfer rates are coupled with an existing material's response code to determine surface recession and char thickness. The calculation is performed for six 5-cm-diam models made of carbon-phenolic and carbon-carbon composite launched in the Track-G facility at the Arnold Engineering Development Center. Significant surface recessions are predicted to occur for these models due mostly to radiative heating.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: AIAA Journal (ISSN 0001-1452); 21; 1588-159
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    A spectral numerical method for the Navier-Stokes equations with applications to Taylor-Couette flow (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: A new spectral method for solving the incompressible Navier-Stokes equations in a plane channel and between concentric cylinders is presented. The method uses spectral expansions which inherently satisfy the boundary conditions and the continuity equation and yield banded matrices which are efficiently solved at each time step. In addition, the number of dependent variables is reduced, resulting in a reduction in computer memory requirements. Several test problems have been computed for the channel flow and for flow between concentric cylinders, including Taylor-Couette flow with axisymmetric Taylor vortices and wavy vortices. In all cases, agreement with available experimental and theoretical results is very good.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Journal of Computational Physics (ISSN 0021-9991); 52; 524-544
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    IPE 7 (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: A description is given of the collection and treatment of samples of Prochloron cells. The cells of Prochloron were obtained and prepared in the following way. Colonies of the symbiotic host, the giant didemnid ascidian Lissoclinum patella, were collected at low-tide level on reef-flat sand between Kamori Island and Koror, Palau, Western Caroline Islands. The animal colonies were taken, immersed in sea water, to an 8,000-litre holding tank and kept with constantly running sea water at 30 deg. Individual colonies were picked clean of contaminants, rinsed in sea water buffered with 40 nM or 100 mM Tris buffer at pH 8.4, and squeezed by hand to express the algal cells from the cloacal atria. The algae were received in about an equal volume of the same buffered sea water; this neutralized the acids liberated by the bruised ascidians and thereby maintained the Ph high enough to keep the algal cells green. The Prochloron cells were washed twice with buffered sea water and concentrated by centrifugation at about 50 g for 90 seconds. Microscopic examination revealed that contamination by animal host cells or bacteria was negligible (much less than 1%).
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Prochloron Res.; 2 p
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    Prochloron-ascidian symbioses: Photosynthetic potential and productivity (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The chlorophyll content of didemnid asidians with symbiotic algae (Prochloron) from oligotropic tropical marine waters around Palau, Western Carolin Islands is discussed. Several species contain as much chlorophyll per unit dry weight as many herbaceous crop plants and more than do other symbiotic associations such as lichens, green Hydra, etc. Their chlorphyllA/B ratios (3-9) were generally much lighter than those of angiosperms (2-4). Where they abound, Prochloron - ascidian symbiosis could make a major contribution to the productivity, especially in localized areas of tropical marine waters characterized by low nutrient levels and high irradiance.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Prochloron Res.; 11 p
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    Prochloron on synaptula (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: It is reported that, for the first time, Prochloron cells were found associated with an animal other than a colonial ascidian-namely, a synaptid holothurian, Snaptula lamperti. This occurance brings into question the supposedly obligate nature of the association of this problematic algae with didemnids and their allies.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Prochloron Res.; 8 p
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    A comparative study of the fatty acid composition of prochloron lipids (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The chemical analysis of lipids of Prochloron isolated from several hosts is discussed. The object was to determine whether differences in lipid composition could be used to characterize organisms from different sources. Major lipid components are given. An analysis of fatty acid composition of individual lipids slowed a distinctive disstribution of fatty acids. While present results do not justify the use of fatty acid content in the taxonomy of Prochlon, the variations found in the lipids of cells from the same host harvested from different areas, or at different times in the same area, suggest that a study of the effects of temperature and light intensity on lipid composition would be rewarding.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Scripps Institution of Oceanography Prochloron Res.; 10 p
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    Report of prochloron research, IPE-7 (Palau, February 1982) (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Various aspects of Prochloron research are discussed. At suitable low-tide periods about 5-6 new sites were surveyed as possible convenient sources of symbiotic didemnids. The Kanori Channel site peviously surveyed during IPE-VI remains by far the best, in terms of species, quantities and accessibility. Prochloron from the six major species of symbiotic didemnids was compared serum, cell size and vacuolation, etc. Tadpoles from Lissoclinum patella colonies were observed emerging from cloacal apertures; about 400 were collected. All but 4 carried a girdle of symbiotic Prochloron cells (about 40,000 per larva). Observations were made on cell viability indicated that a marked increase in protoplasm viscosity of the cell contents was associated with cell death. Living cells, in 5 microlitres of buffered sea water under a coverslip, when pressed with a 2 kg weight for 10 seconds, attempts made to culture Prochloron in sea-water media.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Prochloron Res.; 4 p
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    Report of Prochloron research (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The goal was to assay enzynes in situ in Prochloron, and to prepare active enzyme preparations for future use. In addition, photosynthesis as an indicator of whole cell viability was measured. This indicator was used to monitor extended survival of Prochloron cells after their removal from the host animal.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Scipps Institution of Oceanography Prochloron Res.; 3 p
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    Prochloron expedition (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The purpose was to prepare Prochloron phototsynthetic membranes for the isolation of the two major chlorophyll-proteins, the p700-chlorophyll a protein and the light harvesting chlorophyll a/b-protein, using SDS-polyacrylamide get electrophoreses. The prepared proteins (purified) were examined for their cross-reactivity to polyclonal antibodies prepared from higher plant proteins. In addition, material was prepared for electron microscopy, and isolation of the DNA for determination of its general complexity (COT analysis) and similarity to barley chloroplast DNA and Anabaena DNA by using restriction-endonuclease analysis Kleinschmidt spreads of the DNA were in the electron microscope to identify and measure the extent and size of the circular DNA.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Scripps Institution of Oceanography Prochloron Res.; 3 p
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    Chlorophyll and carotenoid pigments of prochloron (prochlorophyta) (1983)
    In:  Other Sources
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    Publikationsdatum: 2011-08-18
    Beschreibung: High-performance liquid chromatography (HPLC) with a gradient-elution technique was utilized to separate and quantify chlorophylls a and b as well as major carotenoid pigments present in freeze-dried preprations of prochloron-didemnid associations and in Prochloron cells separated from host colonies. Results confirm earlier spectrophotometric evidence for both chlorophylls a and b in this prokaryote. Chlorophyll a:b ratios range from 4.14 to 19.71; generally good agreement was found between ratios determined in isolated cell preprations and in symbiotic colonies (in hospite). These values are 1.5 to 5-fold higher than ratios determined in a variety of eukaryotic green plants. The carotenoids in Prochloron are quantitatively and qualitatively similar to those found in various freshwater and marine blue-green algae (cyanopbytes) from high-light environments. However, Prochloron differs from cyanophytes by the absence of myxoxanthophyll and related glycosidic carotenoids. It pigment characteristics are considered sufficiently different from those of cyanophytes to justify its assignment to a separate algal division.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Prochloron Res.; 17 p
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  • 82
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    Prochloron (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: A review is given of the research problems associated with Prochloron. Two questions are discussed in detail. Did prochlorophytes arise in independently off cyanophytes, or did one of these classes arise from the other? If eukaryotic chlorophytes originated by symbiogenesis, might their plastids have arisen from symbiotic, endophytic prochlorophyte-like ancestors?
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Prochloron Res.; 17 p
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  • 83
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    Diurnal rhythm in the cell-division frequency of prochloron (prochlorophyta) in nature (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Frequencies of cell division stages in suspensions of Prochloron cells, expressed at regular intervals throughout a natural day-night cycle from several colonies of four species of host didemnid, are given. The proportion of dividing cells of Prochloron living symbiotically in colonies of a didemnid, Diplosoma virens, rises from about 4% during the night (20.00-04.00 hrs.) to about 13% in the morning (0,.00-12.00 hrs.), and then falls again in the afternoon. Similiar, though less pronounced, changes were observed among Prochloron cells in two other symbiotic didemnids, Lissoclinum patella and L. voeltzkowi.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Prochloron Res.; 13 p
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  • 84
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    Techniques for the inorganic analysis in a controlled ecological life support system (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Sample preparation, instrumental analysis, a direct injection device for IC/ICP interfacing, a hydraulic jet bend impaction device, monodisperse aerosol generator, and low gravity environments are discussed.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Inorgan. Anal. in a Controlled Ecol. Life Support System; 12 p
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  • 85
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    Standard research materials: Feces and urine (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Preparation of the standard research materials, preparation of the samples for analysis, elemental analysis, composition of standard research materials, and methodology are discussed.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Inorg. Anal. in a Controlled Ecol. Life Support System; 9 p
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  • 86
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    Prochloron expedition (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Prochloron requires a source of N. It can obtain this from its didemnid symbiont as NH (sub4) or amino acids or both. It may obtain it from sea water as do free-living algae (FAA), but this is not likely to be the major source due to diomass consideration.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Prochloron Res.; 2 p
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  • 87
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    Numerical computation of transonic flow governed by the full-potential equation (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Basic concepts associated with the numerical solution of elliptic partial differential equations are introduced, and procedures used to solve the full potential equation for transonic flow fields are discussed. Governing equations, classical relaxation schemes and concepts regarding transonic, full potential equation algorithms are covered. The equation transformation and grid generation procedures; full potential spatial differencing schemes; full potential iteration schemes, emphasizing convergence acceleration; and three dimensional applications are presented.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Von Karman Inst. for Fluid Dynamics Computational Fluid Dyn., Vol. 2; 110 p
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  • 88
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    A modified Dodge algorithm for the parabolized Navier-Stokes equations and compressible duct flows (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: A revised version of Dodge's split-velocity method for numerical calculation of compressible duct flow has been developed. The revision incorporates balancing of massflow rates on each marching step in order to maintain front-to-back continuity during the calculation. Qualitative agreement with analytical predictions and experimental results has been obtained for some flows with well-known solutions.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
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  • 89
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    Boundary conditions for the solution of compressible Navier-Stokes equations by an implicit factored method (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: A method is presented for formulating the boundary conditions in implicit finite-difference form needed for obtaining solutions to the compressible Navier-Stokes equations by the Beam and Warming implicit factored method. The usefulness of the method was demonstrated (a) by establishing the boundary conditions applicable to the analysis of the flow inside an axisymmetric piston-cylinder configuration and (b) by calculating velocities and mass fractions inside the cylinder for different geometries and different operating conditions. Stability, selection of time step and grid sizes, and computer time requirements are discussed in reference to the piston-cylinder problem analyzed.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Journal of Computational Physics (ISSN 0021-9991); 52; 54-79
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  • 90
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    Computation of transonic viscous-inviscid interacting flow (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Transonic viscous-inviscid interaction is considered using the Euler and inverse compressible turbulent boundary-layer equations. Certain improvements in the inverse boundary-layer method are mentioned, along with experiences in using various Runge-Kutta schemes to solve the Euler equations. Numerical conditions imposed on the Euler equations at a surface for viscous-inviscid interaction using the method of equivalent sources are developed, and numerical solutions are presented and compared with experimental data to illustrate essential points. Previously announced in STAR N83-17829
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
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  • 91
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    Application of the alternating direction implicit method to the computation of time-dependent compressible convective flows (1983)
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    Publikationsdatum: 2011-08-18
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
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  • 92
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    Aspects of a penalty finite element algorithm for the turbulent three-dimensional parabolic Navier-Stokes equations (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The formal derivation of the three-dimensional parabolic Navier-Stokes equations for subsonic turbulent flow is reviewed. A penalty finite element algorithm is established for numerical solution of the sixteen dependent variable system. Key numerical results are summarized documenting applications in various problem definitions.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
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  • 93
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    Research on the adaptation of skeletal muscle to hypogravity Past and future directions (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The results of previous research on the cellular effects of microgravity on rat tissue are reviewed and areas of future necessary research are identified. The rats were flown on board Cosmos 605, 782, and 936. Postflight tissue analyses revealed increases in connective tissue cells and focal disruption of muscle fibers due to the microgravity environment of space. Evidence has been found for muscular and neural changes occurring as a result of reentry stresses. It is suggested that a data base be established for quantizing muscle function with electromyography, measurements of force output, and length measurement. The data can serve as a reference for comparisons with data obtained in orbiting laboratories such as the Spacelab. The experiments will have a goal of defining and preventing the mechanism of neuromuscular atrophy.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: (ISSN 0273-1177)
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  • 94
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    Finite element computational fluid mechanics (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Finite element analysis as applied to the broad spectrum of computational fluid mechanics is analyzed. The finite element solution methodology is derived, developed, and applied directly to the differential equation systems governing classes of problems in fluid mechanics. The heat conduction equation is used to reveal the essence and elegance of finite element theory, including higher order accuracy and convergence. The algorithm is extended to the pervasive nonlinearity of the Navier-Stokes equations. A specific fluid mechanics problem class is analyzed with an even mix of theory and applications, including turbulence closure and the solution of turbulent flows.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
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  • 95
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    Changes in total body calcium balance with exercise in the rat (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: The purpose of this study was to evaluate the effect of deconditioning on the total body calcium in rats. Two separate experiments were performed using female Sprague-Dawley rats, 187-266 days of age. Total body calcium was measured in experimental and control rats during and following several weeks of voluntary exercise. The slope from the least-squares fit of total body calcium with time was used to obtain an average calcium balance for each animal during each study period. In both groups, the exercised rats had a significantly decreased calcium balance after cessation of exercise, whereas no significant change was seen in nonexercised controls. In both groups, the exercised animals gained calcium at a significantly greater rate than controls. The findings indicate that while exercised rats may gain calcium at a faster rate compared with nonexercising controls, the rate of gain following cessation of exercise is less than in the controls.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology (ISSN 0161-7567); 55; July 198
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  • 96
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    Morphological and convective instabilities during solidification (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Linear stability theory is employed in the present analysis of flow stability between two vertical, infinite, rigid coaxial cylinders at different temperatures. These calculations have been prompted by, and are found to be in general agreement with, experiments on succinonitrile. A long, vertical cylinder sample of this material was heated so that a vertical melt annulus formed between the coaxial heater and the surrounding crystal/melt interface. Above a critical Grashof number of about 200, a helical crystal/melt interface formed which steadily rotated about the cylinder axis and whose wave speed was several orders of magnitude lower than the base flow velocity.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: (ISSN 0273-1177)
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  • 97
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    Negatively supercoiled simian virus 40 DNA contains Z-DNA segments within transcriptional enhancer sequences (1983)
    In:  Other Sources
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    Publikationsdatum: 2011-08-18
    Beschreibung: Three 8-base pair (bp) segments of alternating purine-pyrimidine from the simian virus 40 enhancer region form Z-DNA on negative supercoiling; minichromosome DNase I-hypersensitive sites determined by others bracket these three segments. A survey of transcriptional enhancer sequences reveals a pattern of potential Z-DNA-forming regions which occur in pairs 50-80 bp apart. This may influence local chromatin structure and may be related to transcriptional activation.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: Nature (ISSN 0028-0836); 303; June 23
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  • 98
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    Effect of spaceflight on periosteal bone formation in rats (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Male Wistar rats were placed in orbit for 18.5 days aboard the Soviet COSMOS 1129 biological satellite. Tetracycline was administered before and after spaceflight to label areas of bone formation. An inhibition of periosteal bone formation occurred during spaceflight in the tibial and humeral diaphyses, but this defect was corrected during the postflight period. The increased extent of arrest lines at these skeletal sites suggested that periosteal bone formation may have even ceased during spaceflight. The rib exhibited a small but nonsignificant decrease in periosteal bone formation. Endosteal bone resorption was not affected markedly by spaceflight conditions. The observed inhibition of periosteal bone formation may be a result of mechanical unloading, but endocrine factors cannot be ruled out.
    Schlagwort(e): LIFE SCIENCES (GENERAL)
    Materialart: American Journal of Physiology (ISSN 0002-9513); 244; 1983
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  • 99
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    Mode propagation in nonuniform circular ducts with potential flow (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: Previously cited in issue 07, p. 969, Accession no. A82-20290
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: (ISSN 0001-1452)
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  • 100
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    The evolution of Tollmien-Schlichting waves near a leading edge. II - Numerical determination of amplitudes (1983)
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    Publikationsdatum: 2011-08-18
    Beschreibung: In the first part of this investigation, Goldstein (1983) has shown that the amplitude of the spatially growing Tollmien-Schlichting wave generated by a time-harmonic free-stream disturbance is related to the coefficient multiplying the lowest-order asymptotic eigensolution of the unsteady boundary-layer equation. In the present study, a numerical solution of the unsteady boundary-layer equation is used to relate the amplitude of the asymptotic eigensolution, and consequently of the Tollmien-Schlichting wave, to that of the imposed free-stream disturbance for the special case of a uniformly pulsating stream. It is pointed out that the ideas of this study can be extended to other, more complex bodies and free-stream oscillations.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: Journal of Fluid Mechanics (ISSN 0022-1120); 129; April 19
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