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At least 145 records · Page 8Linked to original sources
PubMed1991

Oculomotor function during space flight and susceptibility to space motion sickness.

Horizontal vestibulo-ocular reflex (VOR) and saccadic eye movements (SEM) were studied in 18 subjects before and during five Space Shuttle missions to evaluate the effects of weightlessness and correlations between results and susceptibility to and actual presence of space motion sickness (SMS). Active sinusoidal head oscillation was the stimulus for VOR tests with vision (VVOR), with eyes shaded (VOR-ES), and VOR suppression (VOR-S). Eye movements were recorded by electrooculography and head position by a potentiometer. No pathological nystagmus or other abnormal eye movements were seen. No significant in-flight changes were seen in the gain, phase shift or waveform of VVOR, VOR-ES, or VOR-S. Statistically significant increases in saccadic latency and decreases in saccadic velocity were seen, with no change in saccadic accuracy. Preflight differences between SMS susceptible and non-susceptible subjects were noted only in VOR-S, with less complete suppression in susceptible subjects, a finding also seen in flight. During flight, VVOR gain was significantly increased in three non-affected subjects. Saccades of SMS-affected subjects showed increased latency and velocity and decreased accuracy compared to saccades of unaffected subjects.

Adult↗
PubMed2004

Maximum geometrical hindrance to diffusion in brain extracellular space surrounding uniformly spaced convex cells.

Brain extracellular space (ECS) constitutes a porous medium in which diffusion is subject to hindrance, described by tortuosity, lambda = (D/D*)1/2, where D is the free diffusion coefficient and D* is the effective diffusion coefficient in brain. Experiments show that lambda is typically 1.6 in normal brain tissue although variations occur in specialized brain regions. In contrast, different theoretical models of cellular assemblies give ambiguous results: they either predict lambda-values similar to experimental data or indicate values of about 1.2. Here we constructed three different ECS geometries involving tens of thousands of cells and performed Monte Carlo simulation of 3-D diffusion. We conclude that the geometrical hindrance in the ECS surrounding uniformly spaced convex cells is independent of the cell shape and only depends on the volume fraction alpha (the ratio of the ECS volume to the whole tissue volume). This dependence can be described by the relation lambda = ((3-alpha)/2)1/2, indicating that the geometrical hindrance in such ECS cannot account for lambda > 1.225. Reasons for the discrepancy between the theoretical and experimental tortuosity values are discussed.

Brain↗
PubMed2002

Crickets in space: morphological, physiological and behavioral alterations induced by space flight and hypergravity.

"Crickets in Space" was a Neurolab experiment by which the balance between genetic programs and the gravitational environment for the development of a gravity sensitive neuronal system was studied. The model character of crickets was justified by their external gravity receptors, identified position-sensitive interneurons (PSI) and gravity-related compensatory head response, and by the specific relation of this behavior to neuronal arousal systems activated by locomotion. These advantages allowed to study the impact of modified gravity on cellular processes in a complex organism. Eggs, 1st, 4th and 6th stage larvae of Acheta domesticus were used. Post-flight experiments revealed a low susceptibility of the behavior to micro- and hypergravity while the physiology of the PSI was significantly affected. Immunocytological investigations revealed a stage-dependent sensitivity of thoracic GABAergic motoneurons to 3 g-conditions concerning their soma sizes but not their topographical arrangement. The morphology of neuromuscular junctions was not affected by 3 g-hypergravity. Peptidergic neurons from cerebral sensorimotor centers revealed no significant modifications by microgravity (micro g). The contrary physiological and behavioral results indicate a facilitation of 1 g-readaptation originating from accessory gravity, proprioceptive and visual sense organs. Absence of anatomical modifications point to an effective time window of micro g or 3 g-expo-sure related to the period of neuronal proliferation. The analysis of basic mechanisms of how animals and man adapt to altered gravitational conditions will profit from a continuation of the project "Crickets in Space".

Adaptation, Physiological↗
PubMed2002

Dose equivalents inside the MIR Space Station measured by the combination of CR-39 plates and TLDs and their comparison with those on Space Shuttle STS-79, -84 and -91 missions.

In 1997, four dosimeter packages, each of which contains two CR-39 plates and 18 TLDs (Mg2SiO4:Tb), were placed inside the MIR Space Station and flew on an orbit with an inclination angle of 51.6 degrees and an altitude of approximately 400 km for 40 days. We estimated the absorbed doses, dose equivalents and effective quality factors during the flight by combining CR-39 data and TLD data. We then compared these results to those obtained with the same analysis method from the dosimeter packages on board Space Shuttle missions STS-79, -84 and -91 that flew along the same orbit. Finally, the differences between our results and those obtained by another group using passive dosimeters on the MIR are discussed.

Cosmic Radiation↗
PubMed1977

Auditory-visual interactions and the correspondence between perceived auditory space and perceived visual space.

Changes in the physical rate of a clicking or fluttering sound caused changes in the rate at which a simultaneously viewed light appears to flicker, even though the physical flicker rate remains constant. Perceived flicker rate increases in response to a rate of change of flicker frequency, and this auditory 'driving' does not depend on whether the auditory and visual sources have the same location. Visual evoked potentials do not correlate with 'driving'. Thus, the effect of auditory flutter upon perceived visual frequency is not due to the properties of Morrell-type bimodal neurons, nor does it reflect the activities of neurons responsible for maintaining correspondence between perceived auditory space and perceived visual space. The effect is possibly due to modification of a subjective criterion rather than, as previously suggested, to the entrainment or time-locking of physiological signals in the visual pathway.

Auditory Perception↗
PubMed1987

A model of the extradural space and a reappraisal of the extradural space pressure.

A model is described which was used to study the genesis of the pressure in the extradural space. It consists of a Perspex outer tube, with perforations covered with rubber septa to allow the insertion of needles, and Paul's tubing on the inside, representing the dura mater. The Paul's tubing is filled with water through a constant head of pressure apparatus. The response of the model to the insertion of an extradural needle and the reproduction of various clinical phenomena are described. The pressure in the extradural space is discussed in relation to the performance of the model.

Epidural Space↗
PubMed2005

Men are more accurate than women in aiming at targets in both near space and extrapersonal space.

Men excel at motor tasks requiring aiming accuracy whereas women excel at different tasks requiring fine motor skill. However, these tasks are confounded with proximity to the body, as fine motor tasks are performed proximally and aiming tasks are directed at distal targets. As such, it is not known whether the male advantage on tasks requiring aiming accuracy is because men have better aim or is better in the proximal domain in which the task is usually presented. 18 men (M age = 20.6 yr., SD = 3.0) and 20 women (M age = 18.7 yr., SD = 0.9) performed 2 tasks of extrapersonal aiming accuracy (>2 m away), 2 tasks of aiming accuracy performed in near space (< 1 m from them), and a task of fine motor skill. Men outperformed women on both the extrapersonal aiming tasks, and women outperformed men on the task of fine motor skill. However, a male advantage was observed for one of the aiming tasks performed in near space, suggesting that the male advantage for aiming accuracy does not result from proximity.

Adolescent↗
PubMedDate not supplied

Communicatory routes connecting the middle ear, the inner ear and the subarachnoid space via perineural space.

Twenty-one rabbits received injection of Indian ink into the stylomastoid foramen. Observation of the serial sections of their temporal bones revealed Indian ink infiltration into the subarachnoid space, along the facial nerve, the auricular branch of the vagus nerve and the tympanic nerve. Along the acoustic nerve, the infiltration was found as far as the fundus of the internal auditory meatus. In some cases, however, Indian ink reached the subarachnoid space and infiltrated into the scala tympani, scala vestibuli and around the saccule by way of the cochlear aqueduct. These routes are suspected to be a course of spreading infection or tumor cells.

Animals↗
PubMed1985

From space exploration to utilization of the space perspective, environment, and materials. The 1985 Harvey Cushing oration.

As a planetary geologist, the author has analyzed results of the various space missions. Based upon this knowledge, he examines the benefits for mankind to be derived from exploration of the solar system. Findings from Venus and Mars have a bearing on Earth's history and geological make-up and climate. Plans to utilize the Moon's minerals and gases are being considered, and the possibility of capturing asteroids as a source of materials has been suggested. The author expresses the hope of peaceful cooperation in space among the major industrialized nations.

History, 20th Century↗
PubMed1991

Our experience in the evaluation of the thermal comfort during the space flight and in the simulated space environment.

The paper presents the results of the mathematical modelling the effects of hypogravity on the heat output by the spontaneous convection. The theoretical considerations were completed by the experiments "HEAT EXCHANGE 1" performed on the biosatellite "KOSMOS 936". In the second experiment "HEAT EXCHANGE 2" accomplished on the board of the space laboratory "SALYUT 6" was studied the effect of the microgravity on the thermal state of a man during the space flight. Direct measurement in weightlessness prowed the capacity of the developed electric dynamic katathermometer to check directly the effect of the microgravity on the heat output by the spontaneous convection. The role of the heat partition impairment's in man as by the microgravity, so by the inadequate forced convection are clearly expressed in changes of the skin temperature and the subjective feeling of the cosmonaut's thermal comfort. The experimental extension of the elaborated methods for the flexible adjustment of the thermal environment to the actual physiological needs of man and suggestions for the further investigation are outlined.

Body Temperature Regulation↗
PubMed1984

Measurement of Aggregation of Red Cells in space--a project for the NASA space shuttle.

Progress is described on the advanced stages in design of an instrument for the study of red blood cell aggregation and blood viscosity under near-zero gravity conditions. This paper gives a brief review of the experiment and its background and a description of the design of the instrument intended for space conditions. Summaries are given of solutions to some problems peculiar to a space experiment, particularly blood storage, microscope focusing, experiment control and data acquisition.

Blood Sedimentation↗
PubMed1993

Fungi in space--literature survey on fungi used for space research.

A complete review of the scientific literature on experiments involving fungi in space is presented. This review begins with balloon experiments around 1935 which carried fungal spores, rocket experiments in the 1950's and 60's, satellite and moon expeditions, long-time orbit experiments and Spacelab missions in the 1980's and 90's. All these missions were aimed at examining the influence of cosmic radiation and weightlessness on genetic, physiological, and morphogenetic processes. During the 2nd German Spacelab mission (D-2, April/May 1993), the experiment FUNGI provided the facilities to cultivate higher basidiomycetes over a period of 10 d in orbit, document gravimorphogenesis and chemically fix fruiting bodies under weightlessness for subsequent ultrastructural analysis. This review shows the necessity of space travel for research on the graviperception of higher fungi and demonstrates the novelty of the experiment FUNGI performed within the framework of the D-2 mission.

Cosmic Radiation↗
PubMed2001

Enhanced green fluorescent protein (EGFP) for space radiation research using mammalian cells in the International Space Station.

In the endeavour to assess radiation risks for humans in space the concerted action of all stimuli (e.g. radiation and microgravity) has to be known already at a cellular level. The introduction of reporter genes into mammalian cells which allows the visualisation of modified gene expression levels, signal transduction rates and cell metabolism activities will supply basic information on the cellular response to space radiation. The cloning of the gene for green fluorescent protein (GFP) from the jellyfish Aequorea victoria and its subsequent expression in heterologous systems has established GFP as a unique genetic reporter system for use in a variety of organisms. Unlike other reporters, GFP fluorescence emerges in the absence of substrates or cofactors and allows for non-invasive monitoring in living and in paraformaldehyde-fixed cells. Enhancement of wild-type GFP by human codon optimisation and fluorophore mutation (EGFP) resulted in higher expression levels in mammalian cells and brighter fluorescence. The suitability of EGFP for gene expression studies to be performed on the ISS is shown for recombinant mammalian cells in response to UVC exposure.

Animals↗
PubMed2002

[Chronology of the International Space Station and the Centrifuge: actions taken by Japanese Society for Biological Sciences in Space].

History of the International Space Station (ISS) since its beginning in the early 1980's is shortly summarized. The programmatic objective has been converted several times under many changes in political, economical and social agenda at both domestic and global level. The Centrifuge issue after the cost over-run of the ISS in 2001 is a good case to ask the core subjects and the program concept again. Japanese Society for Biological Sciences in Space has taken several actions for the Centrifuge.

Centrifugation↗
PubMedDate not supplied

["From the original vacuum to space, from space to inhabited spot, from inhabited spot to the black hole"].

There is a surprising analogy between the processes explaining the apparition of the universe as material from the vacuum and the processes explaining the apparition of the human being in that universe: they are a spontaneous rupture of symmetry, which cancels the non determination and the infinite transversability of the vacuum, and in the same way, they determine the animal space, which is infinitely open and turn it into a definite place as sense. The constitution of a mirror phenomenon allows the apparition of particles or allows the human being to say: "I". That is why the human being is a repeat of the origin of matter, creating a symmetrical world as image, a world at the same time different and identical in a simultaneity that gives rise to the word and turns the sense of space into the sense of place.

Humans↗
PubMed2002

Combined k-space q-space pulsed ESR imaging: mapping of restricted diffusion in (FA)(2)PF(6).

A (FA)(2)PF(6) crystal from the family of the quasi-one-dimensional organic conductors was selectively damaged by a beam of Helium ions with a slitted mask placed in the beam's trajectory. Pulsed ESR density weighted imaging of the damaged crystal revealed the appearance of regions where the ESR signal was absent. The one-dimensional motion of the charge carriers was thus restricted to the undamaged sections. The local charge carrier spin dynamics in these restricted areas was probed by combined k-space q-space pulsed ESR imaging. The local expected appearance of the restricted pulsed gradient spin echo (PGSE) "diffusive diffraction" effect is shown. The position of the diffraction minima is compatible with the density imaging results.

Journal Article↗