Microbial detection and monitoring in advanced life support systems like the international space station

Potentially pathogenic microbes and so-called technophiles may form a serious threat in advanced life support systems, such as the International Space Station (ISS). They not only pose a threat to the health of the crew, but also to the technical equipment and materials of the space station. The development of fast and easy to use molecular detection and quantification methods for application in manned spacecraft is therefore desirable and may also be valuable for applications on Earth. In this paper we present the preliminary results of the SAMPLE experiment in which we performed molecular microbial analysis on environmental samples of the ISS as part of an ESA-MAP project.     

Computer simulation of carbon nanotube pull-out from polymer by the molecular dynamics method

The influence of the polymer matrix density, chemical cross-links in the interface, and geometrical defect in the carbon nanotubes (CNTs) on the CNT pull-out from polymer has been analyzed by the molecular dynamics simulation. The interfacial shear strength (ISS) has also been estimated with the change of total potential energy. In the simulation, the crystalline polyethylene matrix is set up in a hexagonal array with the polymer chains parallel to the CNT axis. First, we investigate the effect of the polymer matrix density on the ISS by changing the distance between the chains. Simulated results show that the ISS increases with the increase of matrix density. Next, we examine the cross-link effect on the ISS by adding polyethylene cross-links in the interface. Here, an energy based switching criterion addressing cross-links traveling on the CNT has been proposed. It is found that the presence of cross-links and the cross-link positions affect the ISS. Finally, pentagon–heptagon defect, which reduces the tensile strength of the CNT and has been experimentally observed by Hashimoto et al. [Hashimoto A, Suenaga K, Gloter A, Urita K, Iijima S. Direct evidence for atomic defects in graphene layers. Nature 2004;430:870–3], has been addressed as a geometrical defect in the CNT. When cross-links are present between the CNT and the polymer, this defect reduces the ISS due to the improper connections of cross-links around this defective region.     

Development of perforation hole detection system for space debris impact

There is no effective protective measure against space debris between 1 and 10 cm in diameter. Debris in this size range can perforate the pressurized walls in the International Space Station (ISS). According to the current ISS operating procedures, crews must escape from a punctured module at once. However prompt detection of the perforation hole location is difficult in the current state of the ISS. Therefore it is important to install a detection system to the locate perforation hole on a space structure for both the quick decision of escape direction and repair location. In this study, we propose a perforation hole detection system for space debris impact. This system uses a resistance film attached to the pressurized wall as an area sensor. The effectiveness of this detection system was verified by numerical analysis and pseudo-perforation hole tests but also hypervelocity impact tests.     

NASA utilization of ISS -past, present and future

Construction of International Space Station (ISS) began in 1998, with permanent human occupancy commencing in late 2000. The first NASA research experiment reached ISS in September 2000. The February 2001 launch of the US Laboratory Destiny enabled the gradual outfitting of the module with research facilities and heralded the start of continuous research operations in March 2001. Initially, the NASA utilization program consisted of basic and applied peer-reviewed research in a variety of research disciplines. Between March 2001 and June 2002, as assembly of the station continued, Destiny was outfitted with seven research racks, launched on the Space Shuttle, to support the planned investigations, also transported to and from ISS on the Shuttle. The Columbia accident in February 2003 grounded the Shuttle fleet for more than two years, during which time NASA relied on Russian vehicles for transportation of research material. This along with the reduction of the ISS crew size from three to two, dramatically impacted the research conducted. The January 2004 announcement of the Vision for Space Exploration significantly altered the focus of NASA’s ISS utilization program toward developing medical countermeasures and using ISS as a technology testbed for exploration missions. The resumption of Shuttle flights in July 2005 also resumed the outfitting of Destiny with research racks, with the subsequent return of ISS crew size to three and resumption of ISS assembly. In late 2007-early 2008, we will see the addition of the European Columbus module, with its five research racks and two external payloads, followed by the Japanese Kibo pressurized modules, with two research racks, and the Canadian dexterous robotic arm. Subsequent Shuttle flights will deliver more NASA racks, the Japanese external pay-load platform and NASA external payloads while Japanese H-II Transfer Vehicles (HTV) will deliver racks and external pay-loads. Significant international collaboration is anticipated. Sometime in 2009, the infrastructure should be in place to enable the ISS crew size to increase to six, expanding the capability to conduct research. With the retirement of the Space Shuttle in late 2010, NASA will once again rely on partner vehicles for transportation until a commercial transportation system and the Crew Exploration Vehicle are in place early in the next decade.     

Vibrational effect on thermal diffusion under different microgravity environments

Microgravity environments may provide perspective platforms for studying the phenomenon of thermal diffusion. It is, however, noted that the residual microaccelerations (g-jitters) in space laboratories may affect the accuracy of experiments due to convections that they induce. An appropriate interpretation of experimental results from the Space relies on a thorough understanding of the influence of g-jitters on thermal diffusion. In this paper, we have modelled the thermal diffusion process under different microgravity environments using measured g-jitter data onboard the International Space Station (ISS) and FOTON-12. The fluid system consists of a rectangular cavity filled with a ternary mixture of methane, n-butane and dodecane (50∶20∶30 mol%). A lateral heating condition is applied. Various case scenarios have been studied with respect to different locations in the ISS and FOTON; and a detailed analysis is made in comparison with the ideal zero gravity (0-g) scenario. It is found that the diffusion process is only slightly affected by the g-jitters in both platforms. Recommendations are made according to the findings from this study for the improvement of the accuracy of diffusion experiments in Space.     

Survival of microorganisms representing the three Domains of life inside the International Space Station

The present work was mainly focused to study the response of representative non pathogenic microorganisms to the environment inside the space vehicle at different mission stages (10, 56, and 226 days) within the frame of the Italian ENEIDE mission, from Feb to Oct 2005. Microorganisms were chosen according to their phylogenetic position and cell structures; they were representatives of the three taxonomic domains and belonged to different ecosystems (food, soil, intestinal tract, plants, deep-sea). They were the followings: Thermococcus guaymasensis (Domain Archaea); Saccharomyces cerevisiae (Domain Eucarya); Escherichia coli, Bacillus subtilis, Lactobacillus acidophilus, Enterococcus faecium, Pseudomonas fluorescens, and Rhizobium tropici (Domain Bacteria). As main environmental parameters we were interested in: a) space radiations; b) microgravity; c) temperature. The response of microorganisms was investigated in terms of survival rates, cell structure modifications, and genomic damages. The survival of cells was affected by both radiation doses and intrinsec cell features. As expected, only samples kept on the ISS for 226 days showed significant levels of mortality. Asfar as regard the effect on cell structures, these samples showed also remarkable morphological changes, particularly for Escherichia coli, Enterococcus faecium, and Saccharomyces cerevisiae. The data collected allowed to get new insights into the biological traits of microorganisms exposed to space environment during the flight on a spacecraft. Moreover, the result obtained may be important for the improvement of human conditions aboard space vehicles (nutraceuticals for astronauts and disinfections of ISS modules) and also for the potential development of closed systems devoted to vegetable productions and organic recycling.     

The relationship between body weight and risk of death and serious injury in motor vehicle crashes

We sought to investigate the effect of increased body weight on the risk of death and serious injury to occupants in motor vehicle crashes. We employed a retrospective cohort study design utilizing data from the National Automotive Sampling System, Crashworthiness Data System (CDS), 1993-1996. Subjects in the study included occupants involved in tow-away crashes of passenger cars, light trucks, vans and sport utility vehicles. Two outcomes were analyzed: death within 30 days of the crash and injury severity score (ISS). Two exposures were considered: occupant body weight and body mass index (BMI; kg/m2). Occupant weight was available on 27263 subjects (76%) in the CDS database. Mortality was 0.67%. Increased body weight was associated with increased risk of mortality and increased risk of severe injury. The odds ratio for death was 1.013 (95% CI: 1.007, 1.018) for each kilogram increase in body weight. The odds ratio for sustaining an injury with ISS > or = 9 was 1.008 (95% CI: 1.004, 1.011) for each kilogram increase in body weight. After adjustment for potentially confounding variables (age, gender, seatbelt use, seat position and vehicle curbweight), the significant relationship between occupant weight and mortality persisted. After adjustment, the relationship between occupant weight and ISS was present, although less marked. Similar trends were found when BMI was analyzed as the exposure. In conclusion, increased occupant body weight is associated with increased mortality in automobile crashes. This is probably due in part to increased co-morbid factors in the more overweight occupants. However, it is possibly also due to an increased severity of injury in these occupants. These findings may have implications for vehicle safety design, as well as for transport safety policy.     

玻璃纤维增强聚丙烯复合材料界面结合的研究 1. 界面剪切强度

利用单丝临界断裂长度法研究了玻璃纤维(GF) 与聚丙烯(PP) 的界面结合, 发现在纤维 与基体均未作任何处理以前, PP 与GF 的界面剪切强度( ISS) 只有2. 75M Pa。在GF 经偶联剂处 理情况下, 若在PP 中加入0. 3% 不饱和芳香酰亚胺, ISS 增至4. 42M Pa 提高60%。酸酐改性PP 的使用, 可使ISS 达9. 20M Pa, 提高233. 9%。这一方法不仅可以准确判断PP 与GF 界面结合的 优劣, 而且可以为最终的复合材料设计提供可靠依据。      

Developing an integrating biological dosimeter for spaceflight

Exposure to harmful radiation is one of the major threats to human beings in outer-space; however, the biological consequences of long term exposure are not well understood. It would be useful to have a means of measuring the effect of space radiation on a living organism during space flights. We conducted a pilot project as part of the International Caenorhabditis elegans Experiment First Flight (ICE-First) project on the International Space Station (ISS). Using a mutational capture system, the eT1 balancer, along with other mutation detection systems, we analyzed the mutational effects of the 11 day mission. Upon recovery, classical genetic approaches and comparative genomic hybridization (CGH) microarrays were used to isolate and characterize mutant strains. Although in this short period of time, as expected no increase in mutational background was observed, we were able to demonstrate the potential of this system for longer-term measurement of biological damage. A sixmonth exposure experiment using the same system is currently in progress on the ISS. The relative simplicity and robustness of this model system demonstrate its potential for use as a biological dosimeter.     

Self-propagating combustion synthesis of intermetallic matrix composites in the ISS

Combustion Synthesis experiments have been performed on the ISS (International Space Station) during the Belgian taxi-flight mission ODISSEA in November 2002, in the framework of the ESA-coordinated project COSMIC (Combustion Synthesis under Microgravity Conditions). The main objective of the experiments was to investigate the general physico-chemical mechanisms of combustion synthesis processes and the formation of products microstructure. Within the combustion zone, a number of gravity-dependent phenomena occur, while other phenomena are masked by gravity. Under certain conditions, gravity-dependent secondary processes may also occur in the heat-affected zone after combustion. To study the influence of gravity, a specially dedicated reactor ensemble was designed and used in the Microgravity Science Glovebox (MSG) onboard the ISS. In this work, the experiment design is first discussed in terms of the experimental functionality and reactor ensemble integration in the MSG. To investigate microstructure formation, a sample constituted by a cylindrical portion followed by a conical one, the latter being inserted inside a massive copper block, is used. The experiment focused on the synthesis of intermetallic matrix composites (IMCs) based on the Al-Ti-B system. Depending on the composition, different intermetallic compounds (TiAl and TiAl₃) can be formed as matrix phase while TiB2 represents the reinforcing particulate phase. During the ISS mission, six samples with a relatively high green density of 65%TD have successfully been processed. The influence of the composition on the combustion process will be examined.     

Hyperspectral Imager for the Coastal Ocean: instrument description and first images

The Hyperspectral Imager for the Coastal Ocean (HICO) is the first spaceborne hyperspectral sensor designed specifically for the coastal ocean and estuarial, riverine, or other shallow-water areas. The HICO generates hyperspectral images, primarily over the 400-900 nm spectral range, with a ground sample distance of ≈90 m (at nadir) and a high signal-to-noise ratio. The HICO is now operating on the International Space Station (ISS). Its cross-track and along-track fields of view are 42 km (at nadir) and 192 km, respectively, for a total scene area of 8000 km(2). The HICO is an innovative prototype sensor that builds on extensive experience with airborne sensors and makes extensive use of commercial off-the-shelf components to build a space sensor at a small fraction of the usual cost and time. Here we describe the instrument's design and characterization and present early images from the ISS.     

我国外来入侵种福寿螺分子生物学研究进展

福寿螺是一类恶性外来入侵生物,自20世纪80年代初引种并入侵我国以来,对我国农作物生产和水生生态系统造成了严重的危害.我国已报道的福寿螺入侵种类包括Pomacea canaliculata和P.insularum两种,这两种福寿螺也是东南亚、南亚和北美等多国的入侵种类.这两种福寿螺近年来在世界范围内得到了广泛的研究,现综述这两种福寿螺分子生物学的研究进展,包括种类的分子鉴定、分子系统学及蛋白基因的研究等,并对其分子生物学研究和应用进行了讨论和展望.     

Drosophila GENE Experiment in the Spanish Soyuz Mission to the ISS: II. Effects of the Containment Constraints

In the GENE experiment performed during an 11-day Soyuz Mission to the International Space Station (ISS), we intended to determine if microgravity affects Drosophila metamorphosis processes. Control experiments were performed including a 1g ground control parallel to the ISS flight samples and a Random Position Machine microgravity simulated control. A preliminary analysis of the results indicates that five hundred to one thousand genes change their expression profiles depending on the cut-off levels selected. Especially affected among them are the mitochondrial ones (an example with the respiratory chain is presented). We show here that there is a synergic effect of the constraints introduced to meet the requirements of the space experiment (mainly, a cold step and the use of hermetically closed Type-I containers). The cold transport step to the launch site was introduced to slow down the pupal development. The hermetically closed Type I containers were required to ensure the containment of the fixative (acetone) in the experiment. As shown here, the oxygen concentration inside the container was not optimal but fully compatible with pupal development. It is highly likely that such combined environmental effects will become a common finding in these types of studies as they become more complicated and extensive. They could open the way to understand how the gene expression patterns and the actual phenotypes can adjust to the environment. These findings indicate the importance of a vigorous ground based program in support of real microgravity experiments. Only then we can utilize the ISS in order to understand the consequences of the modified environment in outer space on living organisms.     

Mathematical foundations of the immersed finite element method

In this paper, we propose an immersed solid system (ISS) method to efficiently treat the fluid–structure interaction (FSI) problems. Augmenting a fluid in the moving solid domain, we introduce a volumetric force to obtain the correct dynamics for both the fluid and the structure. We further define an Euler–Lagrange mapping to describe the motion of the immersed solid. A weak formulation (WF) is then constructed and shown to be equivalent to both the FSI and the ISS under certain regularity assumptions. The weak formulation (WF) may be computed numerically by an implicit algorithm with the finite element method, and the streamline upwind/Petrov–Galerkin method. Compared with the successful immersed boundary method (IBM) by Peskin and co-workers (J Comput Phys 160:705–719, 2000; Acta Numerica 11:479–517, 2002; SIAM J Sci Stat Comput 13(6):1361–1376, 1992) the ISS method applies to more general geometries with non-uniform grids and avoids the inaccuracy in approximating the Dirac delta function     

Injury severity scoring: a comparison of early clinical versus discharge diagnosis

The Abbreviated Injury Scale (AIS) and the Injury Severity Score (ISS) are objective means of assessing injury. Accepted methodology involves retrospective scoring of injury based on discharge diagnoses. Recently, early clinical scoring, supplemented by review at discharge, has been introduced. A prospective study was instituted to compare these methodologies. Four hundred sixty consecutive victims of blunt trauma were scored using both clinical and retrospective methodologies by independent, blinded observers. Of these, 333 patients had a change in ISS, 174 with a change of greater than four points. The population mean ISS remained unchanged; however, paired values were significantly different (p less than .03). We conclude that either methodology is applicable for studies of large populations of trauma victims. When accurate individual AIS or ISS scoring is required, the clinical method combined with discharge review is most appropriate.     

The SCD – Stem Cell Differentiation ESA Project: Preparatory Work for the Spaceflight Mission

Due to spaceflight, astronauts experience serious, weightlessness-induced bone loss because of an unbalanced process of bone remodeling that involves bone marrow mesenchymal stem cells (BMSCs), as well as osteoblasts, osteocytes, and osteoclasts. The effects of microgravity on osteo-cells have been extensively studied, but it is only recently that consideration has been given to the role of BMSCs. Previous researches indicated that human BMSCs cultured in simulated microgravity (sim-μg) alter their proliferation and differentiation. The spaceflight opportunities for biomedical experiments are rare and suffer from a number of operative constraints that could bias the validity of the experiment itself, but remain a unique opportunity to confirm and explain the effects due to microgravity, that are only partially activated/detectable in simulated conditions. For this reason, we carefully prepared the SCD – STEM CELLS DIFFERENTIATION experiment, selected by the European Space Agency (ESA) and now on the International Space Station (ISS). Here we present the preparatory studies performed on ground to adapt the project to the spaceflight constraints in terms of culture conditions, fixation and storage of human BMSCs in space aiming at satisfying the biological requirements mandatory to retrieve suitable samples for post-flight analyses. We expect to understand better the molecular mechanisms governing human BMSC growth and differentiation hoping to outline new countermeasures against astronaut bone loss.     

Shear failure characterization of time–temperature sensitive interfaces

Poor interlayer bonding can lead to early failures and thus to a reduction in service life of bituminous pavements. For this reason, it is important to identify the parameters influencing the interlayer shear failure and to characterize their effect by means of laboratory test. In particular, this study is focussed on the effects of test temperature and deformation rate on the interlayer shear strength (ISS) of double-layered asphalt concrete specimens. First, the ISS was measured at temperatures ranging from 0 °C to 30 °C and deformation rates ranging from 0.5 mm/min to 9 mm/min using the Ancona Shear Testing Research and Analysis (ASTRA) device. Then the experimental data were analyzed using a two-stage statistical modelling approach. In the first stage, the variation of ISS versus deformation rate, at each testing temperature, was modelled using both a power-law and a logarithmic function. In the investigated range of deformation rate, the models allowed to estimate the mean ISS with residual standard error varying from 0.062 MPa to 0.128 MPa. Moreover, the linear regression coefficients, which measure the influence of the deformation rate on ISS, changed with temperature. In the second stage, both temperature and deformation rate were used as joint predictors of ISS by using an approach based on the superposition of their effects. Results showed that the time–temperature superposition approach is applicable and a sigmoid-shaped master curve for ISS was obtained. The proposed approach was validated by using ISS measurements obtained on the same materials with different test devices.     

SCD – Stem Cell Differentiation Toward Osteoblast Onboard the International Space Station

Microgravity produces a variety of physical, chemical, and biological cues leading to an intricate and largely unresolved network of mechanosensitive molecules, transduction pathways, oxidative stress-related responses, and adaptations. The bone loss observed in astronauts and animal models after spaceflight is attributable to alterations in the bone tissue formation that depends on the continuous remodelling through the activities of bone-resorbing osteoclasts of hematopoietic lineage and bone-forming osteoblast of mesenchymal origin. Focusing on osteogenic differentiation, we present the results of the ”SCD - Stem Cells Differentiation” experiment, aiming to determine how human bone marrow stem cells (hBMSCs) react to a prolonged (approx. 2 weeks) exposure to microgravity in terms of growth, and differentiation when treated with a physiological osteo-inducer as 1,25-dihydroxy vitamin D (Vit D3). The experiment was selected by the European Space Agency and transferred to ISS with the Soyuz-TMA- 16M (ISS 42S). It was carefully prepared because experiments performed on ISS remain a uniquely exceptional means of clarifying the microgravitational effects on osteogenesis, often only partially activated and detectable under simulated conditions. Because of the substantial reduction in calcification observed (about 50% inflight vs. on-ground control), we looked at significantly affected pathways in hBMSCs grown in microgravity vs. on-ground controls. Genome-wide expression changes were assessed via microarray and next generation sequencing (NGS) and integrated with exosomal mi-RNA measurements. Multi-scale pathway analysis of the omics datasets revealed evidence of cell cycle arrest, occurring with a number of osteogenic gene markers, but without indications of adipogenesis, senescence and/or apoptosis.     

Vicarious calibrations of HICO data acquired from the International Space Station

The Hyperspectral Imager for the Coastal Ocean (HICO) presently onboard the International Space Station (ISS) is an imaging spectrometer designed for remote sensing of coastal waters. The instrument is not equipped with any onboard spectral and radiometric calibration devices. Here we describe vicarious calibration techniques that have been used in converting the HICO raw digital numbers to calibrated radiances. The spectral calibration is based on matching atmospheric water vapor and oxygen absorption bands and extraterrestrial solar lines. The radiometric calibration is based on comparisons between HICO and the EOS/MODIS data measured over homogeneous desert areas and on spectral reflectance properties of coral reefs and water clouds. Improvements to the present vicarious calibration techniques are possible as we gain more in-depth understanding of the HICO laboratory calibration data and the ISS HICO data in the future.     

Maintenance, reliability and policies for orbital space station life support systems

The performance of productive work on space missions is critical to sustaining a human presence on orbital space stations (OSS), the Moon, or Mars. Available time for productive work has potentially been impacted on past OSS missions by underestimating the crew time needed to maintain systems, such as the Environmental Control and Life Support System (ECLSS). To determine the cause of this apparent disconnect between the design and operation of an OSS, documented crew time for maintenance was collected from the three Skylab missions and Increments 4–8 on the International Space Station (ISS), and the data was contrasted to terrestrial facility maintenance norms. The results of the ISS analysis showed that for four operational and seven functional categories, the largest deviation of 60.4% over the design time was caused by three of the four operational categories not being quantitatively included in the design documents. In a cross category analysis, 35.3% of the crew time was found to have been used to repair air and waste handling systems. The air system required additional crew time for maintenance due to a greater than expected failure rate and resultant increased time needed for repairs. Therefore, it appears that the disconnect between the design time and actual operations for ECLSS maintenance on ISS was caused by excluding non-repair activities from the estimates and experiencing greater than expected technology maintenance requirements. Based on these ISS and Skylab analyses, future OSS designs (and possibly lunar and Martian missions as well) should consider 3.0–3.3 h/day for crews of 2 to 3 as a baseline of crew time needed for ECLSS maintenance.