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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Increase of plasma renin activity in male and female rabbits subjected to dysbaric conditions

The renin-angiotensin-aldosterone system may be implicated in hemodynamic alterations occurring in dysbaric disorders. This report concerns changes in plasma renin activity (PRA) induced by exposure of rabbits to a compression-decompression schedule that does not normally produce clinical manifestations of decompression sickness. The results revealed a significant increase in PRA in 19 of 23 animals following dysbaric exposure. Mean PRA rose from 1.18 ng ang I/ml hr (preexposure) to 2.40 ng ang I/ml hr (postexposure). The increase was particularly pronounced in female animals (217 percent). Asymptomatic intravascular gas bubbles (silent bubbles) were detected by gross or microscopic examination in the majority of the animals. Renin elaboration and secretion in asymptomatic dysbaric exposures may be mediated by bradykinin and/or prostaglandins released or activated in a chain reaction triggered by silent gas bubbles. This hypothesis is also applicable to increased PRA in altitude decompression. Alternatively elevation of PRA may result from decreased renal perfusion when dysbaric disorders are complicated by significant hypovolemia.

Chryssanthou, C.↗
NASA NTRS1989

Effects of simulated weightlessness and sympathectomy on maximum VO2 of male rats

The effects of simulated weightlessness (hind-limb suspension) and chemical sympathectomy (by repeated injections with guanethidine sulfate) on the maximum oxygen consumption (VO2 max) of female rats were investigated in rats assigned for 14 days to one of three groups: a head-down hind-limb suspension, a horizontal suspension with hind limbs weight bearing, or the caged control. The VO2 max values were assessed by having rats run on a treadmill enclosed in an airtight chamber. The hind-limb-suspended sympathectomized rats were found to exhibit shorter run times and lower mechanical efficiencies, compared to their presuspension values or the values from saline-injected suspended controls. On the other hand, the suspended sympathectomized rats did not demonstrate a decrease in the VO2 max values that was observed in saline-injected controls.

Woodman, C. R.↗
NASA NTRS1995

Effects of chronic elevated levels of CO2 on the concentration of blood cellular elements and plasma corticosterone in the male rat

The mean CO2 concentration on the Space Shuttle is 0.3% and has reached 0.7%, for extended periods of time. Following space flight, it has been shown that both humans and animals have significant changes in red blood cell counts (RBC) and white blood cell counts (WBC). In other studies, where no significant change did occur in the total WBC, a significant change did occur in the distribution of WBC. WBC are affected by circulating levels of glucocorticoids, which often increase when animals or humans are exposed to adverse and/or novel stimuli (e.g. elevated CO2 levels or weightlessness). The purpose of this study was to determine if elevations in CO2 concentration produce changes in total WBC and/or their distribution.

Alexander, R. A.↗
NASA NTRSDate not supplied

Baseline Assumptions and Ersatz Waste Streams for Partial Gravity Habitats with Mobile Female and Male Crew

Effective and reliable water management and recovery systems will be required to support human missions beyond the low Earth orbit (LEO) of the International Space Station (ISS). Lunar and Mars surface missions will introduce new challenges to managing water and associated waste streams from mobile crew members who are transiting between up to six living shelters in extreme environmental conditions under a range of gravity conditions. A review of baseline assumptions for the human activities and associated air and water cycles in and between transit vehicle, orbiting station, lander-ascent vehicle, surface habitat, pressurized rover, and suits is conducted. The paper updates ersatz formulations and water flow rates for the main liquid water waste streams of urine, humidity condensate, hygiene, and laundry. Emphasis is placed on the metabolic emissions partitioning between the six vehicles during a design reference mission scenario. Ersatz to represent menses are reviewed.

Dean L Muirhead↗
NASA NTRSDate not supplied

Baseline Assumptions and Ersatz Waste Streams for Partial Gravity Habitats with Mobile Female and Male Crew

Effective and reliable water management and recovery systems will be required to sup-port human missions beyond the low Earth orbit (LEO) of the International Space Station (ISS). Lunar and Mars surface missions will introduce new challenges to managing water and associated waste streams from mobile crew members who will be living in up to six shelters in extreme environmental conditions under a range of gravity conditions. A review of baseline assumptions for the human activities and associated air and water cycles in and between the transit vehicle, orbiting station, lander-ascent vehicle, surface habitat, pressurized rover, and suits is conducted. The paper reviews ersatz formulations and water flow rates for the main liquid water waste streams of urine, humidity condensate, hygiene, and laundry. Emphasis is placed on the metabolic emissions partitioning between the six habitat elements and the lunar exosphere during a design reference mission scenario.

Water Ersatz Habitat↗
NASA NTRSDate not supplied

Baseline Assumptions and Ersatz Waste Streams for Partial Gravity Habitats with Mobile Female and Male Crew

Effective and reliable water management and recovery systems will be required to sup-port human missions beyond the low Earth orbit (LEO) of the International Space Station (ISS). Lunar and Mars surface missions will introduce new challenges to managing water and associated waste streams from mobile crew members who will be living in up to six shelters in extreme environmental conditions under a range of gravity conditions. A review of baseline assumptions for the human activities and associated air and water cycles in and between the transit vehicle, orbiting station, lander-ascent vehicle, surface habitat, pressurized rover, and suits is conducted. The paper reviews ersatz formulations and water flow rates for the main liquid water waste streams of urine, humidity condensate, hygiene, and laundry. Emphasis is placed on the metabolic emissions partitioning between the six habitat elements and the lunar exosphere during a design reference mission scenario.

Water Ersatz Habitat↗
DOE OSTI2019

Comparative efficacy of valnoctamide and sec ‐butylpropylacetamide ( SPD ) in terminating nerve agent–induced seizures in pediatric rats

Summary Objectives Children and adults are likely to be among the casualties in a civilian nerve agent exposure. This study evaluated the efficacy of valnoctamide (racemic‐VCD), sec ‐butylpropylacetamide (racemic‐SPD), and phenobarbital for stopping nerve agent seizures in both immature and adult rats. Methods Female and male postnatal day ( PND ) 21, 28, and 70 (adult) rats, previously implanted with electroencephalography (EEG) electrodes were exposed to seizure‐inducing doses of the nerve agents sarin or VX and EEG was recorded continuously. Five minutes after seizure onset, animals were treated with SPD , VCD, or phenobarbital. The up‐down method was used over successive animals to determine the anticonvulsant median effective dose (ED 50 ) of the drugs. Results SPD‐ED 50 values in the VX model were the following: PND 21, 53 mg/kg (male) and 48 mg/kg (female); PND 28, 108 mg/kg (male) and 43 mg/kg (female); and PND 70, 101 mg/kg (male) and 40 mg/kg (female). SPD ‐ ED 50 values in the sarin model were the following: PND 21, 44 mg/kg (male) and 28 mg/kg (female); PND 28, 79 mg/kg (male) and 34 mg/kg (female); and PND 70, 53 mg/kg (male) and 53 mg/kg (female). VCD ‐ ED 50 values in the VX model were the following: PND 21, 34 mg/kg (male) and 43 mg/kg (female); PND 28, 165 mg/kg (male) and 59 mg/kg (female); and PND 70, 87 mg/kg (male) and 91 mg/kg (female). VCD ‐ ED 50 values in the sarin model were the following: PND 21, 45 mg/kg (male), 48 mg/kg (female); PND 28, 152 mg/kg (male) 79 mg/kg (female); and PND 70, 97 mg/kg (male) 79 mg/kg (female). Phenobarbital‐ ED 50 values in the VX model were the following: PND 21, 43 mg/kg (male) and 18 mg/kg (female); PND 28, 48 mg/kg (male) and 97 mg/kg (female). Phenobarbital‐ ED 50 values in the sarin model were the following: PND 21, 32 mg/kg (male) and 32 mg/kg (female); PND 28, 58 mg/kg (male) and 97 mg/kg (female); and PND 70, 65 mg/kg (female). Significance SPD and VCD demonstrated anticonvulsant activity in both immature and adult rats in the sarin‐ and VX ‐induced status epilepticus models. Phenobarbital was effective in immature rats, whereas in adult rats, higher doses were required that were accompanied by toxicity. Overall, significantly less drug was required to stop seizures in PND 21 animals than in the older animals, and overall, males required higher amounts of drug than females.

Haines, Kari M.↗
DOE OSTI2013

Environmental Impacts of Wind Power Development on the Population Biology of Greater Prairie-Chickens

1. We investigated the impacts of wind power development on the demography, movements, and population genetics of Greater Prairie-Chickens (Tympanuchus cupido) at three sites in northcentral and eastern Kansas for a 7-year period. Only 1 of 3 sites was developed for wind power, the 201MW Meridan Way Wind Power Facility at the Smoky Hills site in northcentral Kansas. Our project report is based on population data for prairie chickens collected during a 2-year preconstruction period (2007-2008), a 3-year postconstruction period (2009-2011) and one final year of lek surveys (2012). Where relevant, we present preconstruction data from our field studies at reference sites in the northern Flint Hills (2007-2009) and southern Flint Hills (2006-2008). 2. We addressed seven potential impacts of wind power development on prairie chickens: lek attendance, mating behavior, use of breeding habitat, fecundity rates, natal dispersal, survival rates, and population numbers. Our analyses of pre- and postconstruction impacts are based on an analysis of covariance design where we modeled population performance as a function of treatment period, distance to eventual or actual site of the nearest wind turbine, and the interaction of these factors. Our demographic and movement data from the 6-year study period at the Smoky Hills site included 23 lek sites, 251 radio-marked females monitored for 287 bird-years, and 264 nesting attempts. Our genetic data were based on genotypes of 1,760 females, males and chicks that were screened with a set of 27 microsatellite markers that were optimized in the lab. 3. In our analyses of lek attendance, the annual probability of lek persistence during the preconstruction period was ~0.9. During the postconstruction period, distance to nearest turbine did not have a significant effect on the probability of lek persistence. However, the probability of lek persistence increased from 0.69 at 0 m to 0.89 at 30 km from turbines, and most abandoned lek sites were located <5 km from turbines. Probability of lek persistence was significantly related to habitat and number of males. Leks had a higher probability of persistence in grasslands than agricultural fields, and increased from ~0.2 for leks of 5 males, to >0.9 for leks of 10 or more males. Large leks in grasslands should be a higher priority for conservation. Overall, wind power development had a weak effect on the annual probability of lek persistence. 3. We used molecular methods to investigate the mating behavior of prairie chickens. The prevailing view for lek-mating grouse is that females mate once to fertilize the clutch and that conspecific nest parasitism is rare. We found evidence that females mate multiple times to fertilize the clutch (8-18% of broods, 4-38% of chicks) and will parasitize nests of other females during egg-laying (~17% of nests). Variable rates of parentage were highest in the fragmented landscapes at the Smoky Hills field site, and were lower at the Flint Hills field site. Comparisons of the pre- and postconstruction periods showed that wind energy development did not affect the mating behaviors of prairie chickens. 4. We examined use of breeding habitats by radio-marked females and conducted separate analyses for nest site selection, and movements of females not attending nests or broods. The landscape was a mix of native prairie and agricultural habitats, and nest site selection was not random because females preferred to nest in grasslands. Nests tended to be closer to turbines during the postconstruction period and there was no evidence of behavioral avoidance of turbines by females during nest site selection. Movements of females not attending nests or broods showed that females crossed the site of the wind power development at higher rates during the preconstruction period (20%) than the postconstruction period (11%), and that movements away from turbines were more frequent during the postconstruction period. Thus, wind power development appears to affect movements in breeding habitats but not nest site selection of female prairie chickens during the breeding season. 5. We tested the effects of wind power development on five components of female fecundity: timing of clutch initiation, clutch size of first nests and renests, nest survival, and hatchability of eggs. Average date of clutch initiation was 26 April, clutch size was 12.7 and 10.6 eggs for first nests and renests, probability of nest survival was low at 0.18, but egg hatchability was high at 0.79. Wind power development had no impact on reproductive effort or nesting success, and all five components of fecundity were not related to treatment period or distance to turbine. Nest survival was the main factor limiting reproductive output of female prairie chickens and most losses were due to predation. Daily nest survival was strongly related to vegetative cover at the nest. Changes to rangeland management practices that would double nesting cover from 2.5 to 5 dm would triple the probability of nest survival from 0.17 to 0.52. Grass and forb cover had weak positive effects on daily nest survival whereas shrub cover, proximity to woodlands, and recent rainfall had negative effects. Reproductive performance of prairie chickens is low in managed rangelands in northcentral Kansas and efforts to improve range conditions and reduce predator activity would aid recovery of prairie chicken populations. 6. We used molecular methods to investigate patterns of natal dispersal in prairie chickens. High rates of nest failure limited the number of young that we could sample. Direct detections of natal dispersal were limited because survival of newly hatched chicks to become adults were low and because we were unable to detect dispersal distances outside of our study area. Direct observations of natal movements were limited and were inadequate to make conclusions about the potential impacts of wind energy development on natal dispersal. Spatial correlograms of genetic distance among males at leks were a more sensitive measure of population structure, and indicated a weak effect of wind energy development on the spatial genetic structure of prairie chickens. 7. We tested the effects of wind power development on female survival with time-to-event models, and on residual body mass of males with analyses of covariance. Distance to turbine and the interaction of distance and treatment period had no effect on female survival. Contrary to predictions of negative impacts of wind power development, the probability of female was lowest during the preconstruction period (0.274) and increased significantly during the postconstruction period (0.543). Inspection of hazard functions indicated that the difference in annual survival could be attributed to a higher risk of mortality during the lekking season in the preconstruction period. We suggest that wind power development may have improved ecological conditions for prairie chickens by disrupting the foraging behavior of diurnal raptors that kill prairie chickens at lek sites. In support of this idea, raptor kills tended to be farther from turbines during the postconstruction period whereas mammalian kills were closer. Analyses of the major causes of mortality did not support our hypothesis because the odds of raptor predation were greater after development was completed. Most mortality losses of radio-marked females were due to predation, and losses to collision mortality or harvest were rare events. Low rates of natural mortality during fall and winter imply that harvest is likely to be additive mortality in prairie chickens. Wind energy development reduced the residual body mass of male Greater Prairie-Chickens at lek sites near turbines. Low values of residual body mass could have a negative impact on individual survival or fecundity rates, or may be related to predation risk and flight performance of males displaying at open lek sites. 8. We tested for impacts of wind power development on population numbers of prairie chickens with monitoring of male numbers at leks, and with genetic measures of population structure. Lek counts indicated that wind power development did not affect the population size of prairie chickens. Peak counts of males at leks were recorded the first year after construction was completed and the highest rates of population change were observed during the interval when the wind power facility was constructed. Population numbers of prairie chickens near and distant from turbines appeared to covary in parallel, probably because bird numbers were linked by dispersal movements. Estimates of population viability based on genetic diversity, effective population size and rates of population exchange did not show annual changes and were unaffected by wind development during our study. Estimates of relatedness among males at the same and different leks suggested that wind power development has either reduced dispersal rates or changed settlement patterns, leading to higher rates of relatedness among males displaying at the same lek site. 9. Greater Prairie-Chickens were not strongly affected by wind power development in Kansas. Negative impacts of wind power development included a trend for reductions in lek persistence near turbines, behavioral avoidance of turbines by females during their breeding season movements, and changes in the genetic structure of males at leks that were consistent with reduced dispersal or recruitment rates. We found no impacts of wind power development on nest site selection, female reproductive effort or nesting success, or population numbers. Positive impacts of wind power development included an increase in female survival rates. We hypothesized that the unexpected increase in female survival was related to changes in trophic interactions and disruption of the foraging behavior of raptors that kill prairie chickens at lek site. 10. Research funding for this project included a grant from the 20% Wind by 2030 Program of the Department of Energy (this final report), and grants from the Kansas Department of Wildlife, Parks and Tourism, the National Fish and Wildlife Federation, and initial funding from the National Wind Coordinating Collaborative. Research products from data collected during the preconstruction period have included five peer-reviewed research articles and two PhD dissertations at Kansas State University. Additional manuscripts are in review for possible publication in 2013-2014.

17 WIND ENERGY↗
DOE OSTI2011

Impact of Gender, Partner Status, and Race on Locoregional Failure and Overall Survival in Head and Neck Cancer Patients in Three Radiation Therapy Oncology Group Trials

Purpose: We investigated the impact of race, in conjunction with gender and partner status, on locoregional control (LRC) and overall survival (OS) in three head and neck trials conducted by the Radiation Therapy Oncology Group (RTOG). Methods and Materials: Patients from RTOG studies 9003, 9111, and 9703 were included. Patients were stratified by treatment arms. Covariates of interest were partner status (partnered vs. non-partnered), race (white vs. non-white), and sex (female vs. male). Chi-square testing demonstrated homogeneity across treatment arms. Hazards ratio (HR) was used to estimate time to event outcome. Unadjusted and adjusted HRs were calculated for all covariates with associated 95% confidence intervals (CIs) and p values. Results: A total of 1,736 patients were analyzed. Unpartnered males had inferior OS rates compared to partnered females (adjusted HR = 1.22, 95% CI, 1.09-1.36), partnered males (adjusted HR = 1.20, 95% CI, 1.09-1.28), and unpartnered females (adjusted HR = 1.20, 95% CI, 1.09-1.32). White females had superior OS compared with white males, non-white females, and non-white males. Non-white males had inferior OS compared to white males. Partnered whites had improved OS relative to partnered non-white, unpartnered white, and unpartnered non-white patients. Unpartnered males had inferior LRC compared to partnered males (adjusted HR = 1.26, 95% CI, 1.09-1.46) and unpartnered females (adjusted HR = 1.30, 95% CI, 1.05-1.62). White females had LRC superior to non-white males and females. White males had improved LRC compared to non-white males. Partnered whites had improved LRC compared to partnered and unpartnered non-white patients. Unpartnered whites had improved LRC compared to unpartnered non-whites. Conclusions: Race, gender, and partner status had impacts on both OS and locoregional failure, both singly and in combination.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Sex-based differences in gene expression in hippocampus following postnatal lead exposure

The influence of sex as an effect modifier of childhood lead poisoning has received little systematic attention. Considering the paucity of information available concerning the interactive effects of lead and sex on the brain, the current study examined the interactive effects of lead and sex on gene expression patterns in the hippocampus, a structure involved in learning and memory. Male or female rats were fed either 1500 ppm lead-containing chow or control chow for 30 days beginning at weaning.Blood lead levels were 26.7 {+-} 2.1 {mu}g/dl and 27.1 {+-} 1.7 {mu}g/dl for females and males, respectively. The expression of 175 unique genes was differentially regulated between control male and female rats. A total of 167 unique genes were differentially expressed in response to lead in either males or females. Lead exposure had a significant effect without a significant difference between male and female responses in 77 of these genes. In another set of 71 genes, there were significant differences in male vs. female response. A third set of 30 genes was differentially expressed in opposite directions in males vs. females, with the majority of genes expressed at a lower level in females than in males. Highly differentially expressed genes in males and females following lead exposure were associated with diverse biological pathways and functions. These results show that a brief exposure to lead produced significant changes in expression of a variety of genes in the hippocampus and that the response of the brain to a given lead exposure may vary depending on sex. - Highlights: > Postnatal lead exposure has a significant effect on hippocampal gene expression patterns. > At least one set of genes was affected in opposite directions in males and females. > Differentially expressed genes were associated with diverse biological pathways.

60 APPLIED LIFE SCIENCES↗