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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effect of unloading by tail-cast suspension on carbohydrate metabolism in skeletal muscle.

Henriksen, Erik John. January 1987 (has links)
The tail-cast suspension system was used as a ground-based model of weightlessness to study the effects of reduced weight-bearing (unloading) and attendant atrophy on carbohydrate metabolism in the rat soleus muscle. Changes in glycogen metabolism during unloading were biphasic. The initial phase, which took place during the first 24 hours, was characterized by increased glycogen concentrations, the result of decreased glycogenolysis. This glycogen accumulation in turn decreased the glycogen synthase activity ratio. These alterations were maintained thereafter. A similar glycogen increase was seen in the soleus unloaded by hypogravity. A rapid decline in glucose uptake also occurred during this initial phase of unloading, both in the absence and presence of insulin. During the second phase of this unloading response, beyond 24 hours, there was an increase in the sensitivity of the soleus to insulin for glucose uptake that coincided with the onset of muscle atrophy. However, this increased insulin sensitivity was not seen for glycogen synthesis, indicating differential regulation of these two processes by insulin. The enhanced insulin sensitivity likely resulted from an increase in the binding capacity for the hormone, resulting from no increased turnover of the insulin receptor during unloading. Additionally, the onset of increased insulin sensitivity coincided with a return to normal of basal glucose uptake, despite the continued unloading. When the 3-day unloaded soleus was reloaded, carbohydrate metabolism returned to normal after a triphasic response. Within two hours, the glycogen concentration decreased below control levels, due to increased glycogenolysis. During the second phase of reloading, from two to 24 hours, glycogen accumulated dramatically due to an enhanced capacity of the muscle for glycogenesis. Insulin sensitivity returned to normal by 24 hours of reloading. In the final phase, beyond 24 hours, glycogen decreased to control values. An uncoupling of the inverse relationship between glycogen and the activity ratio of glycogen synthase was seen beyond four hours of reloading. These effects of unloading and reloading were not due to systemic factors, as the extensor digitorum longus was unaffected. It is apparent that the unloaded soleus is a potent model with which to study the individual factors that regulate carbohydrate metabolism in skeletal muscle.
2

EFFECT OF SIMULATED WEIGHTLESSNESS ON VASCULAR SMOOTH MUSCLE ALPHA RECEPTOR RESPONSIVENESS DURING ACUTE ORTHOSTASIS.

Blamick, Cynthia Ann. January 1985 (has links)
No description available.
3

The biomechanical effects of bone demineralization during simulated weightlessness

Garber, Mitchell Arthur 12 1900 (has links)
No description available.
4

Effects of simulated weightlessness on skeletal muscle structure and function in the upper arm

Parcell, Allen C. January 1998 (has links)
This investigation examined the effects of 4 weeks of non-dominant arm suspension on the functional and structural characteristics of the triceps brachii muscle of 6 normo-active college age males (age: 23.3 ±0.8 yrs, height: 176.1 ±3.7 cm, weight: 75.9 ±5.8 kg). The primary intent of this study was to determine if arm suspension is an effective analogue for simulating the effects of weightlessness on human skeletal muscle. Subjects were tested 2-3 days preceding suspension in a standard arm sling and immediately following removal of the sling. To suspend the arm the sling was worn during waking hours. Subjects were allowed to remove the sling during sleep and bathing. Specific instructions were given to avoid use of the arm. Torque production (Nm) during maximal isometric extensions at 90° significantly declined (p<0.05) in response to arm suspension (53.93 ±5.07 to 47.90 ±5.92; 12%). There was no significant change (p>0.05) in the force-velocity attributes of the triceps over the other measured velocities (60, 90, 120, 180, 240, 300°/sec). Cross-sectional muscle area (CSA) of the upper arm diminished significantly (44.26 +2.66 to 42.43 ±2.54 cm2; 4%) following the 4 weeks of unloading (p<0.05). Histochemical analysis of individual muscle fibers demonstrated reductions in fiber CSA of 27 and 18% for type I and type II fibers, respectively, however these changes were not statistically significant (p>0.05). Amplitude of the IEMG signal during maximal isometric contraction of the long head of the triceps fell (p<0.05) by 21 in response to the 4 week suspension period. The changes in triceps muscle structure and function found with arm suspension are similar in magnitude and direction to data obtained from humans following exposure to real and simulated weightlessness. These findings suggest that arm suspension may provide a useful model for simulating the effects of microgravity on human skeletal muscle. / School of Physical Education
5

Human disorientation as a factor in spacecraft centrifuge design /

Howse, Christopher E. January 2002 (has links) (PDF)
Thesis (M.S. in Space Systems Operations)--Naval Postgraduate School, September 2002. / Thesis advisor(s):Stephen A. Whitmore, Sherif Michael. Includes bibliographical references. Also available online.
6

Nothing : how can some buildings have the sensatio[n] of weightlessness? An explanatory document submitted in partial fulfillment of the requirements for the degree of Master of Architecture, UNITEC [New Zealand] /

Rödel, Harry. January 2008 (has links)
Thesis (M. Arch)--Unitec New Zealand, 2008. / Includes bibliographical references (leaves 100-104).
7

Functional and morphological responses of human skeletal muscle to resistance and aerobic exercise during simulated weightlessness

Moore, Melinda Sheffield January 1997 (has links)
The conductor of a large instrumental ensemble is constantly confronted with the task of detecting and correcting rhythm and pitch performance errors in daily rehearsals. The purpose of this investigation was to design a computer-assisted instruction program for error detection skills development and then evaluate this program's effectiveness in training beginning conductors to identify rhythm and pitch errors within 2-, 3-, 4-, and 5-voice synthesized music excerpts from the existing band literature. The transfer of error detection skills from synthesized to acoustic sounds also was explored indirectly by virtue of utilizing taped excerpts from wind band performances to assess error detection skills.Subjects (N=24) in this study were drawn from the pool of undergraduate instrumental music education majors at Ball State University and were randomly assigned to control treatment groups prior to the administration of the Acoustic Error Detection Skills Inventory. Following this pretest, the treatment group used the Computer Error Detection Skills Program for approximately eight hours during an eight week treatment period. At the end of the treatment period, and control and treatment groups were administered the Acoustic Error Detection Skills Inventory posttest.The data were analyzed using a series of one-way, repeated measures analyses of variance (ANOVA) to assess pretest to posttest changes in subjects' scores on the Acoustic Error Detection Skills Inventory. Composite scores (reflecting general skill in error detection) improved significantly for the treatment group (p = .007), while the pretest to posttest gain for the control group was not statistically significant (p = .232). These results suggest that the Computer Error Detection Skills Program was effective in enhancing subjects' rhythm and pitch error detection skills and the viability of using synthesized sound sources for training was confirmed.The following recommendations were made: (1) Jazz directors need to do more listening to jazz music, (2) band directors who direct jazz programs should join IAJE, (3) jazz ensembles shouldtheir own improvisational skills, and rehearse in the fall, (4) jazz ensemble directors should develop (5) jazz ensemble directors should have their students sing their parts during rehearsals for increased learning efficiency and retention. / Human Performance Laboratory
8

Histochemical and biochemical changes in human muscle following 17 days of unilateral lower limb suspension

Short, Kevin R. January 1997 (has links)
The present study was undertaken to determine the relationship between perinatal complications and subsequent development of Attention Deficit Hyperactivity Disorder (ADHD) and other behavioral characteristics. The biological mothers of 74 children diagnosed with ADHD and 77 children displaying no characteristics of the disorder completed the Maternal Perinatal Scale (MPS), the Behavior Assessment System for Children-Parent Rating Scales (BASC-PRS), and a demographic survey. In addition, the biological mothers of 120 children with no characteristics of ADHD or any other behavior disorders completed only the MPS so that exploratory factor analysis of the MPS could be completed.Following factor analysis, stepwise discriminant analysis of the resulting five factors was utilized to explore the nature of the relationship between such perinatal factors and ADHD. Results of this analysis indicated that emotional factors, or the amount of stress encountered during pregnancy and the degree to Relationship Between Perinatal Complications 3 was planned, were the items that maximized the separation between the ADHD and Non-ADHD groups. Additional discrimination between the groups was attributed to the extent of insult or trauma to the developing fetus and the outcome of prior pregnancies. ADHD children were also found to have experienced twice as many behavioral, social, or medical problems, and were more likely to reach developmental milestones with delays.Stepwise discriminant analysis also revealed the Attention Problems and Hyperactivity scales of the BASC-PRS were most significant in differentiating between the ADHD and Non-ADHD subjects. Using the BASC-PRS resulted in approximately 90% of the total sample being correctly classified as ADHD or Non-ADHD. Canonical correlation analysis indicated that emotional factors and the general health of both the mother and the developing fetus were the best predictors of later behavioral patterns reported on the BASC-PRS. / Human Performance Laboratory
9

Mechanisms and countermeasures of microgravity-induced bone loss in vitro and in vivo model systems /

Saxena, Ritu. January 2009 (has links) (PDF)
Thesis (Ph.D.)--University of Alabama at Birmingham, 2009. / Title from PDF title page (viewed on July 19, 2010). Includes bibliographical references.
10

Pharmacokinetics and pharmacodynamics of ciprofloxacin in simulated microgravity

Schuck, Edgar Luis, January 2004 (has links)
Thesis (Ph.D.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 190 pages. Includes Vita. Includes bibliographical references.

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