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Wunder, C. C.

Publications and source records attributed to Wunder, C. C..

16 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Knee-ligament loading properties as influenced by gravity. I - Junction with bone of 3-G rodents

The effect of 3-G conditions on the bone-to-ligament junctions of the knee is studied in rats. Results following chronic 3-G centrifugation of rats show that their bone-to-ligament junctions exhibited a force-sustaining capacity (F) which was 95 + or - 12% of the value for the control group. However, F was actually 29 + or - 5% greater for centrifuged rats than for control rats of comparable size, as the experimental animals grew to smaller body mass. It is concluded that gravity determines part of the magnitude of F, and therefore this value will probably be weaker after development in a weightless environment.

Wunder, C. C.↗
NASA NTRS1980

Femur-bending properties as influenced by gravity. IV - Limits after high and low weight-bearing

Gravity enhances femur growth as measured in terms of strength, but shows little or even a growth-retarding effect in terms of relative brittleness, defined as the inverse of ultimate or tolerable strain. Chronic weightlessness was simulated by harness suspension or by extrapolation of results from 3-g centrifugation. Experimental results from 45 male, white rats (34-520 d old) were compared to 72 control or baseline rats (28-520 d old) with correction for age and size differences. After suspension, the youngest rats showed subnormal tolerable strains. Combined results, however, although predicting 19 + or 1% below normal strength, after a week of weightlessness, predicted less effect (1 + or - 4%) for the tolerable strain.

Wunder, C. C.↗
NASA NTRS1977

Femur-bending properties as influenced by gravity. I - Ultimate load and moment for 3-G rats

Fresh experimental bones can withstand greater bending forces and moments after 1.0 to 2.5 weeks of 3-G exposure. This appears more attributable to a 50% greater strength of bone material than to effects upon size or shape, and is most measurable for animals of 5 to 8 weeks of age. Experimental bone material seems to grow to its mature level at a younger age rather then there being so marked an effect upon the mature level itself. We simulated 3.1 G by chronic centrifugation of 66 albino rats and compared them to 63 1-G controls. Extrapolation of the simplest mathematical description of the present results to weaker, zero-G bones could be tested by a total of 60 space-based control and experimental animals. A flight of only 15 animals would be necessary for comparison to ground-based control animals. This is consistent with reports of bone demineralization during space-flight. In light of the differences in bone histology, however, extrapolation of these results to humans would be premature and, if at all applicable, are most likely to be so for children rather than adults.

Wunder, C. C.↗
NASA NTRS1974

Gravitational force as a determinant of turtle-shell growth and shape

Chronic low-gravity simulation (pedestal support, suspension by wires or foam, and/or clinostat tumbling) of 11 aquatic red-eared sliders, Pseudemys scripta elegans, and of nine box turtles, Terrapine carolina, resulted in continued but slower linear carapace growth. Decreased shell height was accompanied by drastic plastron infolding. Chronic centrifugation (1.4, 1.8, 2.8, 5, or 8.1 g) of 81 box turtles caused an eventual decrease (12% per g) in linear growth rate. No consistent decrease occurred with aquatic turtles centrifuged at below 6 g. Maximum growth of length and roundness appears near 5 g for aquatic environments and near 1 g in land environments. Present results suggest that some gravity is necessary for normal bone growth.

Wunder, C. C.↗
NASA NTRS1974

Gravitational considerations with animal rhythms

As established in the laboratory and largely confirmed by others, simulated high-g environments influence growth and development of animals as small as or smaller than baby turtles, sometimes accelerating and sometimes decelerating these processes. High-g environments result in many functional changes or adjustments in feeding, metabolism, circulation, fluid balances, and structures for support, and influence life expectancy. An assembly of equipment suitable for measuring oxygen consumption of small mammals as influenced by chronic centrifugation and/or by day-night rhythms is discussed.

Wunder, C. C.↗
NASA NTRS1973

Oxygen consumption measurements during continual centrifugation of mice.

A simple method is described for measurement of metabolism of conscious, unrestrained animals, during chronic centrifugation or other conditions of isolation (23.75 hr/day) from the investigators in an essentially normal atmospheric environment for as long as seven days. This involves telemetry of pressure changes in a metabolic chamber. At 7 G's, increased O2 intake lasting two to seven days and a decreased excursion of the day-night difference were measured for male white mice with less effect or even an opposite effect at lower fields. Base-line measurements of metabolic rate per mouse are less affected by animal size than expected from the surface area law.

Fethke, W.↗
NASA NTRS1969

Nature of pleural space of dogs

Pleural space of dogs investigated by spheres injection of varying density and diameter, discussing sedimentation velocities

Cronin, L.↗
NASA NTRS1968

Methods of simulating weightlessness.

Weightlessness simulation, discussing mechanics of biological effects, simulation of specific anticipated effects and concept of mechanical acceleration and gravity equivalent effects

Bengele, H.↗