Advanced biostack: experiment 1 ES 027 on Spacelab-1.

The radiobiological properties of the heavy ions of cosmic radiation were investigated on Spacelab 1 by use of biostacks, monolayers of biological test organisms sandwiched between thin foils of different types of nuclear track detectors. Biostacks were exposed to cosmic radiation at several locations with different shielding environments in the module and on the pallet. Evaluations of the physical and biological components of the experiment to date indicate that in general they survived the spaceflight in good condition. Dosimetric data are presented for the different shielding environments.     

Microorganisms and biomolecules in space environment experiment ES 029 on Spacelab-1.

Bacterial spores are proper test organisms for studying problems of space biology and exobiology. During the Spacelab 1 mission, studies on the limiting factors for survival of Bacillus subtilis spores in free space have been performed. An exposure tray on the pallet of Spacelab 1 accomodated 316 samples of dry spores for treatment with space vacuum and/or the following selected wavelengths of solar UV: > 170 nm, 220 nm, 240nm, 260nm and 280 nm. After recovery, inactivation, mutation induction, reparability, and photochemical damages in DNA and protein have been studied. The results contribute to the understanding of the mechanisms of increased UV sensitivity of bacterial spores in vacuo and to a better assessment of the chance of survival of resistant forms in space and of interplanetary transfer of life.     

Radiation effects in nematodes: results from IML-1 experiments.

The nematode Caenorhabditis elegans was exposed to natural space radiation using the ESA Biorack facility aboard Spacelab on International Microgravity Laboratory 1, STS-42. For the major experimental objective dormant animals were suspended in buffer or on agar or immobilized next to CR-39 plastic nuclear track detectors to correlate fluence of HZE particles with genetic events. This configuration was used to isolate mutations in a set of 350 essential genes as well as in the unc-22 structural gene. From flight samples 13 mutants in the unc-22 gene were isolated along with 53 lethal mutations from autosomal regions balanced by a translocation eT1(III;V). Preliminary analysis suggests that mutants from worms correlated with specific cosmic ray tracks may have a higher proportion of rearrangements than those isolated from tube cultures on a randomly sampled basis. Right sample mutation rate was approximately 8-fold higher than ground controls which exhibited laboratory spontaneous frequencies.     

Changes in operational procedures to improve spaceflight experiments in plant biology in the European Modular Cultivation System

The microgravity environment aboard orbiting spacecraft has provided a unique laboratory to explore topics in basic plant biology as well as applied research on the use of plants in bioregenerative life support systems. Our group has utilized the European Modular Cultivation System (EMCS) aboard the International Space Station (ISS) to study plant growth, development, tropisms, and gene expression in a series of spaceflight experiments. The most current project performed on the ISS was termed Seedling Growth-1 (SG-1) which builds on the previous TROPI (for tropisms) experiments performed in 2006 and 2010. Major technical and operational changes in SG-1 (launched in March 2013) compared to the TROPI experiments include: (1) improvements in lighting conditions within the EMCS to optimize the environment for phototropism studies, (2) the use of infrared illumination to provide high-quality images of the seedlings, (3) modifications in procedures used in flight to improve the focus and overall quality of the images, and (4) changes in the atmospheric conditions in the EMCS incubator. In SG-1, a novel red-light-based phototropism in roots and hypocotyls of seedlings that was noted in TROPI was confirmed and now can be more precisely characterized based on the improvements in procedures. The lessons learned from sequential experiments in the TROPI hardware provide insights to other researchers developing space experiments in plant biology.     

Progress in European CELSS activities.

The European CELSS activities started in the late 1970's with system analysis and feasibility studies of Biological Life Support Systems (BLSS). Since then the European efforts have continued in two major directions: as a series of individual development tasks like the Environmental Life Support System and the Solar Plant Growth Facility, and in parallel hereto as overall coordination and planning activities for life support system long term needs definition and payload definition for COLUMBUS utilization. The early initiations for CELSS came from the industry side in Europe, but since then planning and hardware feasibility analyses have been initiated also from customer/agency side. Despite this, it is still to early to state that a "CELSS-programme" as a "concerted" effort has been agreed upon in Europe. However, the general CELSS objectives have been accepted as planning and possible development goals for the European effort for manned space activities, and as experimental planning topics in the life sciences community for the next decades.     

Telescience testbed for biomedical experiments in space morphological and physiological experiments of rat musculoskeletal system.

As the second telescience testbed experiment we were examined sophisticated processes of biomedical experiment, such as an implantation of a transmitter into the hamster's abdominal cavity, non-stressful blood sampling, large amount of blood collection, muscle extirpation and biopsy from the hamsters on February 6-8, 1990. To make clear the differences between successful results obtained by an experienced hand and by a non-experienced one, three operators were selected for three successive experimental days; an engineer who had never experienced any biological experiment, a non-biology student, who experienced on biological experiments, and a veterinary surgeon. Surgical procedures need much experiences on maneuvering and understanding of theory to shorten the elapse time. Especially for a non-experienced hand, graphic instructions were much helpful to understand and to maneuver the procedures. Continuous recordings of ECG from a operator and PIs were of an advantage to grasp an extent of the mental strain, which was compared with their reports requested after end of each experimental day. The mental strain was not related to degrees of scientific achievement, but showed faithfully difficulty of each experimental procedure. Training effects on PIs in successive experimental days were found in their instructions for the operator to let understand the procedures.     

Allometry in vestibular responses of anurans

Frogs and toads turn either their heads or bodies opposite to angular accelerations applied around the yaw axis. Thresholds exist for the minimum angular acceleration that induces this vestibulomotor response in individual frogs. These thresholds were recorded for several anuran species that cover a broad range of sizes and life styles. Interspecific variation in the magnitude of the thresholds, which correlated with the ecology and behavior of the species, was documented. Also an allometric relationship was observed between this threshold and body size; the larger the frog, the lower the threshold. In many species, the threshold value for reflexive vestibulomotor responses to angular acceleration was proportional to the -0.4 (+/-0.2) power of body mass. Physical dimensions of the semicircular canals determine, in part, vestibular sensitivity to angular acceleration. Hence changes with growth in the semicircular canals are believed to contribute to the slope of -0.4. The biological significance of this allometry in vestibular responses is discussed and compared to trends in vestibular sensitivity and semicircular canal morphology of other vertebrate classes.     

The low energy gamma-ray experiments on GRO in perspective

The NASA Gamma-Ray Observatory, GRO, will carry two instruments for low energy gamma-ray astronomy. The ‘Oriented Scintillation Spectrometer Experiment - OSSE’ represents the latest step in the evolution of collimated detectors. A large detection area, simultaneous source and background observation and rigorous control over systematic errors yield significant improvements in sensitivity over earlier instruments. The ‘Imaging Compton Telescope - COMPTEL’ brings the proven concept of the Compton telescope to the state of the art level. Position sensitive scintillation detectors make it possible to generate sky images with a resolution of about 2° over a f.o.v. of about 1 sr. The complementary nature of these two experiments promises a first in-depth exploration of the sky in a wavelength range which covers the transition from the X-ray sky to the apparently unrelated high energy gamma-ray sky. Possible directions of further evolution of these experiments will be discussed.     

Plasma wave observations during electron gun experiments on ISEE-1

The ISEE-1 electron guns were operated during the final orbits of ISEE-1 in 1987 in tests designed to study the stimulation of plasma waves. The guns were operated in modes which varied from 10-μA, at 10-eV, to 100-μA at 45-eV. Experiments were run on inbound orbits, while moving from the solar wind into perigee on the dusk side. A broadband emission was generally found from 0.1–10-kHz (e.g. below the plasma frequency). Next, a strong signal was typically induced at about 80-kHz, well above the ambient plasma frequency. This is interpreted as being the plasma frequency associated with the “beam” electrons. There were occasionally intensifications of the naturally occurring signals at the electron cyclotron frequency and the electron plasma frequency (or upper hybrid resonance).     

Influence of gravitoinertial force on vestibular nystagmus in man observed in a centrifuge.

The influence of gravity load on the vestibular system in man was investigated in a centrifuge operating on the free swing principle. The vertical vestibular nystagmus induced by acceleration to 3G was analyzed and compared with reference measurements during 1G. Our data indicate that the effects of increased gravity load include a prolonged decay time constant of upbeat nystagmus and a subject-dependent persisting upbeat nystagmus. In an attempt to explain these findings, an extension of the velocity storage model is proposed, with gravity as a second stimulus function in addition to angular acceleration.     

Preparations for CELSS flight experiments with wheat.

We are planning a short-term experiment with Superdwarf wheat on the U.S. Space Shuttle and a seed-to-seed experiment on the Russian Space Station Mir. The goals of both experiments are to observe effects of microgravity on developmental steps in the life cycle and to measure photosynthesis, respiration, and transpiration by monitoring gas exchange. This requires somewhat different hardware development for the two experiments. Ground-based research aims to understand plant responses to the environments in the space growth chambers that we will use (after some modification): the Plant Growth Unit (PGU) on the shuttle and units called Svet, Svetoblock 2, or Oasis on Mir. Low irradiance levels (100 to 250 micromoles m-2 s-1 at best) pose a particular problem. Water and nutrient supply are also potentially limiting factors, especially in the long-term experiment. Our ground-based studies emphasize responses to low light levels (50 to 400 micromoles m-2 s-1); results show that all developmental steps are delayed by low light compared with plants at 400 micromoles m-2 s-1. We are also testing various rooting substrates for the shuttle experiment. A 1:1:1 mixture of peat:perlite:vermiculite appears to be the best choice.     

Large-size space laboratory for biological orbit experiments.

The study of space factors on living systems has great interest and long-term experiments during orbital flight will be important tool for increasing our knowledge. Realization of such experiments is limited by constraints of modern space stations. A new technology of large-size space laboratory for biological experiments has been developed on the basis of polymerization techniques. Using this technique there are no limits of form and size of laboratory for a space station that will permit long term experiments on Earth orbit with plants and animals in sufficient volume for creation of closed self-regulating ecological systems. The technology is based on experiments of the behavior of polymer materials in simulated free space conditions during the reaction of polymerization. The influences of space vacuum, sharp temperature changes and space plasma generated by galactic rays and Sun irradiation on chemical reaction were evaluated in their impact on liquid organic materials in laboratory conditions. The results of our study shows, that the chemical reaction is sensitive to such space factors. But we believe that the technology of polymerization could be used for the creation of space biological laboratories in Earth orbit in the near future.     

Cellular changes in microgravity and the design of space radiation experiments.

Cell metabolism, secretion and cell-cell interactions can be altered during space flight. Early radiobiology experiments have demonstrated synergistic effects of radiation and microgravity as indicated by increased mutagenesis, increased chromosome aberrations, inhibited development, and retarded growth. Microgravity-induced changes in immune cell functions include reduced blastogenesis and cell-mediated, delayed-type hypersensitivity responses, increased cytokine secretions, but inhibited cytotoxic effects and macrophage differentiation. These effects are important because of the high radiosensitivity of immune cells. It is difficult to compare ground studies with space radiation biology experiments because of the complexity of the space radiation environment, types of radiation damage and repair mechanisms. Altered intracellular functions and molecular mechanisms must be considered in the design and interpretation of space radiation experiments. Critical steps in radiocarcinogenesis could be affected. New cell systems and hardware are needed to determine the biological effectiveness of the low dose rate, isotropic, multispectral space radiation and the potential usefulness of radioprotectants during space flight.     

Chairman's introduction: mechanisms, models and experiments in space radiation research.

Radiation risk estimate in space is a moral obligation and a scientific challenge requiring the combined efforts of physicists and biologists. This introductory paper presents some thoughts about problems to be solved and the possible directions of research. It stresses the necessity of cooperation across disciplines and the combination of space and ground based investigations.     

A quantitative assay of biologically important compounds in simulated primitive Earth experiments.

A CH4-N2-H2OV gas mixture was subjected to a high voltage (20 kV), high frequency (0.3 MHz) electric discharge. The energy input in the electric discharge was varied from 0.016 to 3.048 MJ mol-1. The chemical yields (G), expressed as the number of molecules formed or destroyed per 100 eV of energy input were calculated for several products. The G values calculated at the lowest energy input were (-CH4) = 6.48; (-N2) = 2.51; (C2H2) = 1.16; (HCN) = 0.215; (CH3CHO) = 0.115; (CH3CH2CHO) = 0.00161; (CH3(CH2)2CHO) = 0.0165; ((CH2CO2H)2) = 0.0000339; (CH4 --> Solid material) = 0.196; (N2 --> Solid material) = 0.00355. This is the first report in prebiotic studies in which the G values of various products in electric discharge experiments are determined. This type of study is needed in order to get a better insight into the relative role of electric discharges on the primitive Earth.     

Adaptations of the vestibular system to short and long-term exposures to altered gravity.

Long-term space flight creates unique environmental conditions to which the vestibular system must adapt for optimal survival of a given organism. The development and maintenance of vestibular connections are controlled by environmental gravitational stimulation as well as genetically controlled molecular interactions. This paper describes the effects of hypergravity on axonal growth and dendritic morphology, respectively. Two aspects of this vestibular adaptation are examined: (1) How does long-term exposure to hypergravity affect the development of vestibular axons? (2) How does short-term exposure to extremely rapid changes in gravity, such as those that occur during shuttle launch and landing, affect dendrites of the vestibulocerebellar system? To study the effects of longterm exposures to altered gravity, embryonic rats that developed in hypergravity were compared to microgravity-exposed and control rats. Examination of the vestibular projections from epithelia devoted to linear and angular acceleration revealed that the terminal fields segregate differently in rat embryos that gestated in each of the gravitational environments.To study the effects of short-term exposures to altered gravity, mice were exposed briefly to strong vestibular stimuli and the vestibulocerebellum was examined for any resulting morphological changes. My data show that these stimuli cause intense vestibular excitation of cerebellar Purkinje cells, which induce up-regulation of clathrin-mediated endocytosis and other morphological changes that are comparable to those seen in long-term depression. This system provides a basis for studying how the vestibular environment can modify cerebellar function, allowing animals to adapt to new environments.     

法兰西新海上游击手——法国展示下一代欧洲多功能护卫舰

法国舰艇建造局（DCN）展示了Gowind-200型系列轻型护卫舰模型，这其实就是欧洲多功能护卫舰通用型的缩小版。21世纪以来．欧洲海军作战思想朝向联合作战、濒海作战、由海上来和支援陆上作战的发展，海军武备也朝着运应新作战思想的需要发展。欧洲新型驱逐舰和护卫舰独领风骚．如英，法、意联合研制的“地平线”级驱逐舰、挪威“内森”级护卫舰、西班牙F100“巴赞”级护卫舰及德国F124“萨克森”级护卫舰等。     

Microgravity (STS-90 Neurolab-Mission) influences synapse formation in a vestibular nucleus of fish brain.

Synapse counting was undertaken by conventional electron microscopy in primary vestibular integration centers (i.e., Nucleus descendens, Nd, and Nucleus magnocellularis, Nm, of the brainstem Area octavolateralis) and in the diencephalic visual Nucleus corticalis (Nc) of spaceflown neonate swordtail fish Xiphophorus helleri as well as in 1 g control siblings. Spaceflight (16 days microgravity, STS-90 Neurolab-Mission) yielded an increase in synaptic contacts only within the vestibular Nd indicating that lack of input resulted in compensation processes. No effect of microgravity, however, was observed in the visual Nc and in the vestibular Nm which is situated in the close vicinity of the Nd. In contrast to the latter, the Nm does not receive exclusively vestibular input, but inputs from the lateral line as well, possibly providing sufficient input at microgravity.     

Growth of plants at reduced pressures: experiments in wheat-technological advantages and constraints.

Procedures and results are presented concerning the growth of wheat plants with variable partial pressures of O2 and N2. Data demonstrate that some growth occurs in pressures as low as 0.1 atmosphere. The growth was similar or higher at 200 mb (0.2 atmosphere) than in normal atmosphere but the development was different. Advantages of the low pressure cultivation, especially in the absence of nitrogen, are discussed, including better ratio volume/mass of plant cultivation module; lower losses of gases by leakage; easier management of photosynthetic oxygen produced by plants.