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Biomedical subjects

Gloria R Leon

Publications and source records attributed to Gloria R Leon.

10 recordsLinked to original sources
PubMed2005

Finger heat flux/temperature as an indicator of thermal imbalance with application for extravehicular activity.

The designation of a simple, non-invasive, and highly precise method to monitor the thermal status of astronauts is important to enhance safety during extravehicular activities (EVA) and onboard emergencies. Finger temperature (Tfing), finger heat flux, and indices of core temperature (Tc) [rectal (Tre), ear canal (Tec)] were assessed in 3 studies involving different patterns of heat removal/insertion from/to the body by a multi-compartment liquid cooling/warming garment (LCWG). Under both uniform and nonuniform temperature conditions on the body surface, Tfing and finger heat flux were highly correlated with garment heat flux, and also highly correlated with each other. Tc responses did not adequately reflect changes in thermal balance during the ongoing process of heat insertion/removal from the body. Overall, Tfing/finger heat flux adequately reflected the initial destabilization of thermal balance, and therefore appears to have significant potential as a useful index for monitoring and maintaining thermal balance and comfort in extreme conditions in space as well as on Earth.

Adult↗
PubMed2005

Men and women in space.

The influence of gender on the social context in which work performance takes place is considered. Women in single and mixed-gender polar expedition groups reported concern for the welfare of a teammate as a significant stressor. All-male teams exhibited higher levels of competitiveness and a lesser tendency to talk about their feelings. Excerpts from expedition debriefing interviews illustrate gender-related patterns noted in extreme environments. Application of these findings for the better selection, training, and performance of mixed-gender space crews is examined. A case study approach to conducting research on crew performance is recommended, and strategies for dealing with confidentiality are discussed.

Adaptation, Psychological↗
PubMed2005

Redirection of biological heat from head to hands to support finger comfort in the cold.

INTRODUCTION: Maintaining hand comfort in the cold while sustaining optimal performance is still a challenge. There has been little research on the efficacy of transporting biological heat from the head to the hands to stabilize finger comfort, although there are notable temperature differences between these two areas in the cold. METHOD: A tubing bypass between the head and the hands was designed as an independent component in a liquid cooling/warming garment (LCWG). Seven subjects (four men, three women) were studied, comparing finger temperature (Tfing) change in two conditions: LCWG with additional bypass; and LCWG without bypass. The protocol consisted of three stages: 1) comfort stabilization, LCWG inlet water temperature 33 degrees C, water in loop in bypass condition 23 degrees C; 2) body cooling, LCWG inlet water temperature 20 degrees C; and 3) rewarming, LCWG inlet water temperature 45 degrees C. RESULTS: The time to reach the 25 degrees C Tfing discomfort criterion was significantly longer in the bypass condition (p < 0.01); Tfing was significantly higher at the same time point when Tfing of 25 degrees C was reached in the control condition (p < 0.01). CONCLUSION: The incorporation of a bypass transferring biological heat from a high to a low skin temperature area has potential to improve local finger comfort and thus increase the time personnel can work in cold environments.

Adult↗
PubMed2004

Comparison of different cooling regimes within a shortened liquid cooling/warming garment on physiological and psychological comfort during exercise.

The aim of this study was to compare the effectiveness of different cooling regime intensities to maintain physiological and subjective comfort during physical exertion levels comparable to that engaged in during extravehicular activities (EVA) in space. We studied eight subjects (six males, two females) donned in our newly developed physiologically based shortened liquid cooling/warming garment (SLCWG). Rigorous (condition 1) and mild (condition 2) water temperature cooling regimes were compared at physical exertion levels comparable to that performed during EVA to ascertain the effectiveness of a lesser intensity of cooling in maintaining thermal comfort, thus reducing energy consumption in the portable life support system. Exercise intensity was varied across stages of the session. Finger temperature, rectal temperature, and subjective perception of overall body and hand comfort were assessed. Finger temperature was significantly higher in the rigorous cooling condition and showed a consistent increase across exercise stages, likely due to the restriction of heat extraction because of the intensive cold. In the mild cooling condition, finger temperature exhibited an overall decline with cooling, indicating greater heat extraction from the body. Rectal temperature was not significantly different between conditions, and showed a steady increase over exercise stages in both rigorous and mild cooling conditions. Ratings of overall comfort were 30% higher (more positive) and more stable in mild cooling (p<0.001). The mild cooling regime was more effective than rigorous cooling in allowing the process of heat exchange to occur, thus maintaining thermal homeostasis and subjective comfort during physical exertion.

Adult↗
PubMed2004

Enhancing circulation to lower limbs during head-down tilt by warming upper body and thighs.

BACKGROUND: Long-duration spaceflight results in deconditioning of the cardiovascular system, loss of fluid volume, bone demineralization, and atrophy of skeletal muscles, particularly affecting the lower limbs. We hypothesized that it is possible to improve blood circulation to the lower extremities in simulated microgravity by forcing the blood to deliver heat to the feet through heating parts of the upper body and thighs. METHODS: In Study 1, seven men and four women were assessed in an environmental chamber with head-down tilt (HDT) at 14 degrees, wearing a newly developed shortened multi-compartment liquid cooling/warming garment (SLCWG) with local tubing networks covering parts of the head, torso, thigh, arms, and hands, with fingers, lower leg, and feet exposed. Study 2 was the same as Study 1 with a new cohort of four men and two women, and the assessment of toe blood perfusion on all subjects. Heat was applied as follows: Stage 1--SLCWG inlet water temperature 33 degrees C to stabilize comfort; Stage 2--inlet water temperature 8-10 degrees C (in combination with HDT) to reach a criterion of 25 degrees C finger temperature (Tfing); and Stage 3--inlet water temperature 45 degrees C to restore Tfing to 33 degrees C. RESULTS: Improvement of foot circulation by delivering more heat to the upper body and thighs was noted; increases in toe temperature (Ttoe) suggest enhanced perfusion. From Stage 2 to 3, there were significant increases in Ttoe (p < 0.05), a significant decrease in diastolic BP (DBP) (p < 0.05), and a significant change across stages in subjective perception of foot comfort (p < 0.001) and foot heat (p < 0.06). Further, toe blood perfusion increased significantly from Stage 2 to 3 (p < 0.05). CONCLUSIONS: Moderate partial heating of the upper body/thighs improved blood circulation in the feet in simulated microgravity by delivering heat to the lower extremities through restriction of heat exchange with the environment in the heated body parts. This technique could serve as a supplemental countermeasure for increasing blood circulation to the lower extremities.

Adult↗
PubMed2002

A 1-year, three-couple expedition as a crew analog for a Mars mission.

This study assessed the intrapersonal and interpersonal functioning of a three-couple expedition group that included a 2 1/2-year-old child which was ice-locked on a boat in the High Arctic during a major portion of the expedition. Personality assessment indicated that team members were generally well adjusted, scoring relatively higher on well-being and achievement and relatively lower on stress reactivity. Weekly mood ratings showed that the group exhibited significantly higher positive than negative affect. Reported negative events were relatively most frequent at the beginning of the Arctic stay and toward the end of the darkness period and were lowest during the initial darkness interval. The period of darkness had both a salutary and negative impact. A highly important means of coping with stress was seeking emotional support from one's partner. Selection of couples with strong bonds with their partner appears to be one viable approach for crew selection for long-duration missions.

Adaptation, Psychological↗
PubMed2002

Conscientiousness and work performance while suffering from acute mountain sickness: a case report.

A 52-yr-old male scientist who participated in a geophysical survey in Antarctica from a field camp located at 3538 m (11,600 ft) experienced specific symptoms of acute mountain sickness (AMS) by Mission Day 9, and full syndrome AMS by Mission Day 12. He was treated at the field camp and evacuated to sea level on the next available flight (Mission Day 15). The concerns of this highly conscientious individual that initial signs of illness, such as fatigue with exertion, could be misinterpreted by others as poor work performance are described. The report focuses on individual personality and group processes that could lead to nondisclosure of symptoms, and the need, particularly in long-duration missions in which evacuation is difficult or impossible, to sensitize personnel to the importance of recognizing and reporting potential health problems.

Acclimatization↗
PubMedDate not supplied

Women and couples in isolated extreme environments: applications for long-duration missions.

Expedition teams provide a number of analogs relevant to crew selection for long-duration space missions. Three groups were studied that varied in team composition. Group 1 was a two woman international dyad that traversed the Antarctic continent in 97 days. Similarities in problem solving approach, respect for each other's opinions, and a collaborative process of decision making were evident. Group 2 was composed of four women, all from different countries, engaged in a six week trek across Greenland. The most important factors in overcoming interpersonal difficulties and contributing to the successful completion of the expedition were mutual respect and motivation to maintain positive and supportive relationships. Group 3 consisted of three married couples from different countries icelocked on a boat in the High Arctic for a 9 month period. The emotional support of and ability to confide in their partner were extremely important in alleviating interpersonal tensions, and contributed to the generally effective functioning of the group. Women add an element of emotional support and help to other team members that is not as evident in all-male groups. Selection of couples with strong bonds to each other is another paradigm for crew selection for extended missions.

Antarctic Regions↗
PubMedDate not supplied

Overview of the psychosocial impact of disasters.

The psychosocial sequelae can be intense and of long duration in the aftermath of natural and technological disasters, as well as terrorist attacks. Post-traumatic stress symptoms and full syndrome disorder, depression, anxiety, somatic complaints, and excessive alcohol use have been demonstrated consistently, particularly following large-scale disasters. This paper examines the psychological research conducted at various intervals after extensive natural disasters, the Three Mile Island and Chernobyl technological accidents, and recent terrorist events in the United States. Factors predictive of the emergence of emotional distress and psychological and physical problems following a disaster also are discussed.

Disasters↗