Exposure to microgravity during spaceflight is known to elicit orientation illusions, errors in sensory localization, postural imbalance, changes in vestibulo-spinal and vestibulo-ocular reflexes, and space motion sickness. The objective of this experiment was to investigate whether an alteration in cognitive visual-spatial processing, such as the perception of distance and size of objects, is ...

This research addresses the flame structure of single aluminum particles burning in air with the emphasis on the transition from spherically symmetric to non-symmetric combustion regime. The unique feature of this work is that free motionless aluminum particles were produced and ignited in both normal and microgravity environments. That allowed us to observe whether the particle flame non-symme...

Orthostatic intolerance (OI) is a major problem following spaceflight, and, during flight, astronauts also experience sleep restriction. We hypothesized that sleep restriction will compound the risk and severity of OI following simulated microgravity and exaggerate the renal, cardioendocrine, and cardiovascular adaptive responses to it. Nineteen healthy men were equilibrated on a constant diet,...

The effects of gravity on opposed-flow flame spread in a confined geometry were investigated experimentally in the 2.2-s drop tower at the NASA Glenn Research Center. Pure oxygen flowed through samples of 0.64-cminner-diameter polyvinyl chloride (PVC) tubing held either horizontally or vertically in a combustion chamber filled with nitrogen. The sample was ignited in normal gravity with a hot w...

Exposure to microgravity during space flight has caused astronauts experience decreased bone density, resulting from resorption by osteoclastic activation. Activation of the nuclear factor-?B ligand (RANKL) RANKL-producing cells, a known osteoclastogenesis-promoting factor, seems be induced under microgravity. However, role cells not yet been demonstrated due lack suitable in vitro organ cultur...

UNLABELLED During space flights, tadpoles of the clawed toad Xenopus laevis occasionally develop upward bended tails (tail lordosis). The tail lordosis disappears after re-entry to 1g within a couple of days. The mechanisms responsible for the induction of the tail lordosis are unknown; physical conditions such as weight de-loading or physiological factors such as decreased vestibular activity ...

Aquatic invertebrate animals such as Amphipods, Gastropods (pond snails), Ostracods and Daphnia (water flea) were placed in water-filled cylindrical vessels together with water plant (hornwort). The vessels were sealed completely and illuminated with a fluorescent lamp to activate the photosynthesis of the plant for providing oxygen within the vessels. Such ecosystem vessels, specially termed a...

Bacteria grown in space experiments under microgravity conditions have been found to undergo unique physiological responses, ranging from modified cell morphology and growth dynamics to a putative increased tolerance to antibiotics. A common theory for this behavior is the loss of gravity-driven convection processes in the orbital environment, resulting in both reduction of extracellular nutrie...

The purpose of this study was to test the hypothesis that differential autoregulation of cerebral and hindquarter arteries during simulated microgravity is mediated or modulated by differential activation of K(+) channels in vascular smooth muscle cells (VSMCs) of arteries in different anatomic regions. Sprague-Dawley rats were subjected to 1- and 4-wk tail suspension to simulate the cardiovasc...

Serious thrombotic and hemorrhagic problems or even fatalities evoked by either microgravity or hypergravity occur commonly in the world. We recently reported that platelet functions are inhibited in microgravity environments and activated under high-G conditions, which reveals the pathogenesis for gravity change-related hemorrhagic and thrombotic diseases. However, the mechanisms of platelet f...