The Frog in Space (FRIS) experiment onboard Space Station Mir: final report and follow-on studies.
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The "Frog in Space" (FRIS) experiment marked a major step for Japanese space life science, on the occasion of the first space flight of a Japanese cosmonaut. At the core of FRIS were six Japanese tree frogs, Hyla japonica, flown on Space Station Mir for 8 days in 1990. The behavior of these frogs was observed and recorded under microgravity. The frogs took up a "parachuting" posture when drifting in a free volume on Mir. When perched on surfaces, they typically sat with their heads bent backward. Such a peculiar posture, after long exposure to microgravity, is discussed in light of motion sickness in amphibians. Histological examinations and other studies were made on the specimens upon recovery. Some organs, such as the liver and the vertebra, showed changes as a result of space flight; others were unaffected. Studies that followed FRIS have been conducted to prepare for a second FRIS on the International Space Station. Interspecific diversity in the behavioral reactions of anurans to changes in acceleration is the major focus of these investigations. The ultimate goal of this research is to better understand how organisms have adapted to gravity through their evolution on earth. (+info)
Semicircular canal-otolith organ interaction during off-vertical axis rotation in humans.
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The aim of this study was to examine the interaction of signals from the semicircular canals and the otolith organs during off-vertical axis rotation (OVAR). We recorded horizontal eye position using electro-oculography in 22 young normal human subjects and stimulated the vestibulo-ocular reflex with both constant velocity trapezoids and sinusoidal yaw rotations, using both earth-vertical axis rotation (EVAR) and OVAR. We found that per-rotatory long vestibulo-ocular reflex (VOR) time constants during velocity trapezoids were shorter for OVAR than for EVAR, suggesting a reduction in the efficacy of the velocity storage system during OVAR. However, when we tested with very-low-frequency sinusoids (0.01 Hz and below), the phase lead of the VOR re head velocity was smaller during OVAR than EVAR, suggesting a longer time constant and enhanced efficacy of velocity storage during OVAR. These rotational responses can be explained by two competing influences of signals from the otolith organs, one that diminishes the effectiveness of velocity storage and another that contributes to an estimate of head velocity. (+info)
Studies of vehicular padding materials.
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The Federal Motor Vehicle Safety Standard 571.201 discusses occupant protection with interior impacts of vehicles. Rule making by the National Highway Traffic Safety Administration (NHTSA) has identified padding for potential injury reduction in vehicles. In these studies, head injury mitigation with padding on vehicular roll bars and brush bars was evaluated. Studies were conducted with free falling Hybrid 50% male head form drops on the forehead and side of the head and a 5% female head. Marked reductions in angular acceleration, as well as Head Injury Criterions (HIC), were observed when compared to unpadded roll bars and brush bars. (+info)
Comparison of real world side impact/rollover collisions with and without thorax airbag/head protection system: a first field experience study.
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After the introduction of the Thorax Airbag (TA) and the Head Protection System (HPS) by BMW there has been a significant reduction of injuries in real-world collisions. Comparison of similar collisions (in-depth collision analyses) of vehicles with and without HPS/TA indicates that the effectiveness of the system was credible. Minor injuries (AIS 1) increase while serious injuries (AIS 3+) are reduced. Based on the limited cases available, a proper statistical sampling could not be achieved at this time, however the results are to be understood as indicative of a trend. (+info)
Ocular injuries due to projectile impacts.
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An animal model has been developed using enucleated porcine eyes to evaluate ocular trauma. The eyes were pressurized to approximately 18 mmHg and mounted in a container with a 10% gelatin mixture. The corneas of sixteen pressurized eyes were impacted by a blunt metal projectile (mass of 2.6 gm, 3.5 gm or 45.5 gm) at velocities of 4.0 to 38.1 m/s. The impacted eyes were evaluated by an ophthalmologist. A numerical classification scheme was used to categorize the severity of the ocular injury. A chi-squared test indicates that the injury level is associated with the kinetic energy (KE) and not the momentum of the projectile. The enucleated eyes began to experience lens dislocations when the KE of the projectile was approximately 0.75 Nm, and retinal injuries when the KE was approximately 1.20 Nm. (+info)
Human maxilla bone response to 30 degrees oriented impacts and comparison with frontal bone impacts.
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The aims of this study were to compare the responses of human maxilla and frontal bones under 30 degrees-oriented impacts. Maxilla and frontal bones of the same subject were impacted by a guided horizontal steel cylinder. Linear acceleration time histories and force time histories were plotted and corridors were proposed for maxilla bone response. Sensitivity of head dynamics in regard to impact energy level and localization showed the protection of the intracranial contents by the facial bones crushing. Injury risk curves were established for impact on frontal bone, showing a 50% risk injury for impact energy of 265 J or impact force of 7500 N. (+info)
Rib fracture patterns and radiologic detection--a restraint-based comparison.
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This paper presents a study of the rib fracture patterns generated in simulated frontal collisions and the visibility of the rib fractures on plain film radiographs. Using 29 cadaver subjects, rib fractures were identified on oblique, lateral, and anteroposterior chest films by five radiologists independently and were compared with fractures found during a detailed necropsy. Physical, geometric, and experimental factors demonstrated an influence on the ability of a radiologist to identify rib fractures on an x-ray. Specifically, the restraint system configuration, the total number of fractures, the circumferential location of the fracture, the rib number, and the aspect (right or left) affected fracture identification. The results verify that torso belt loading produces rib fractures generally located along the path of the belt whereas superimposed airbag loading results in a more distributed and posterolateral fracture pattern. A higher proportion of rib fractures was identified on x-ray for occupants restrained by only a belt (44% of fractures) than for occupants restrained by both a belt and an airbag (24% of fractures). Overall, less than 40% of the rib fractures were detected upon an initial examination of radiographs. After being provided with the location of all fractures, detection increased to 49%. On average, occult rib fractures resulted in an average underreporting of injury severity of more than one AIS level. (+info)
Driver and right-front passenger restraint system interaction, injury potential, and thoracic injury prediction.
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Restrained driver and right-front passenger kinematics and injury outcome in frontal collisions are compared using FARS data and human cadaver sled tests. The FARS data indicate that a frontal airbag may provide greater benefit for a passenger than for a driver. The thoracic injuries sustained by passenger subjects restrained by a force-limited, pretensioned belt and airbag are evaluated, and kinematics are compared to driver-side subjects. The injury-predictive ability of existing thoracic injury criteria is evaluated for passenger-side occupants. Driver and passenger kinematic differences are identified and the implications are discussed. The chest acceleration of the passenger-side subjects exhibited a bimodal profile with an initial (and global) maximum before the subject loaded the airbag. A second acceleration peak occurred as the subject loaded both the belt and the airbag. A similarly restrained driver-side subject loaded the belt and airbag concurrently at the time of peak chest acceleration and therefore did not exhibit this bimodal chest acceleration. (+info)