rss_2.0Materials Sciences FeedSciendo RSS Feed for Materials Sciences Sciences Feed Effects of Gamma and Proton Radiation Exposure on Hematopoietic Cell Counts in the Ferret Model<abstract><title style='display:none'>ABSTRACT</title><p>Exposure to total-body radiation induces hematological changes, which can detriment one’s immune response to wounds and infection. Here, the decreases in blood cell counts after acute radiation doses of γ-ray or proton radiation exposure, at the doses and dose-rates expected during a solar particle event (SPE), are reported in the ferret model system. Following the exposure to γ-ray or proton radiation, the ferret peripheral total white blood cell (WBC) and lymphocyte counts decreased whereas neutrophil count increased within 3 hours. At 48 hours after irradiation, the WBC, neutrophil, and lymphocyte counts decreased in a dose-dependent manner but were not significantly affected by the radiation type (γ-rays verses protons) or dose rate (0.5 Gy/minute verses 0.5 Gy/hour). The loss of these blood cells could accompany and contribute to the physiological symptoms of the acute radiation syndrome (ARS).</p></abstract>ARTICLE2022-01-17T00:00:00.000+00:00Housing in the Animal Enclosure Module Spaceflight Hardware Increases Trabecular Bone Mass in Ground-Control Mice<abstract><title style='display:none'>ABSTRACT</title><p>During spaceflight, mice are housed in specially designed cages called the Animal Enclosure Module (AEM). Utilization of this flight hardware may affect the skeletal properties of housed animals, independent of microgravity considerations. To address this issue, we studied the effect of 13 days of AEM housing versus standard vivarium enclosure on female C57BL/6J mice (n=12/group). The effects of AEM housing were most pronounced in the trabecular compartment. AEM mice had 44% and 144% greater trabecular bone volume fraction and connectivity density, respectively, versus vivarium. A similar response was seen at the proximal humerus. We noted a decrease in proximal tibia osteoclast surface (-65%) and eroded surface (-73%) for AEM versus vivarium, while tibia trabecular mineralizing surface (MS/BS) was nearly three-fold greater. Surprisingly, there was also decreased osteoblast surface, as well as lower osteoid volume, surface, and thickness at this site. The effects of AEM housing on femur cortical bone were modest: there was greater periosteal MS/BS, with no effect at the endocortical surface, and lower femur stiffness. Taken together, we have demonstrated significant effects of AEM housing on ground control mice, particularly in the trabecular bone compartment. These findings suggest that an early increase in bone formation, perhaps due to altered behavior and loading in this unique housing environment, was followed by decreased bone formation and resorption as the animals adapted to their new environment. Characterization of spaceflight animal housing is critical to elucidating the true effects of microgravity on skeletal parameters and for the proper selection of ground-based controls.</p></abstract>ARTICLE2022-01-17T00:00:00.000+00:00Development in Altered Gravity Influences Height in<abstract><title style='display:none'>ABSTRACT</title><p>We investigated the effects of altered gravity on the life cycle of <italic>Dictyostelium discoideum</italic> after and during life-long exposure to one of three altered gravity (<italic>g)</italic> environments: (1) substrate inverted, parallel to and facing the surface of the Earth; (2) hyper-<italic>g</italic>; (3) reduced-<italic>g</italic>. To this end, we measured the height of the final stage of the life cycle, the mature spore-bearing sorocarp. Typically, the sorocarp stands erect and perpendicular to the substrate. In the case of each altered <italic>g</italic> environment, the control cultures were produced and treated identically to the experimental cultures except for the conditions of their exposure to altered <italic>g</italic>. Inverted cultures developing and growing in the same direction as the gravity vector had a mean height of 1.84 mm. Their counterpart control cultures had a mean height of 1.64 mm being therefore statistically significantly shorter. Cultures chronically exposed to a hyper (10) <italic>g</italic> environment produced sorocarps with a mean height of 1.13 mm. These were statistically significantly shorter than their 1 <italic>g</italic> controls whose mean height was 2.06 mm. Clinorotated (simulated reduced <italic>g</italic>) sorocarp heights (mean equal to 2.12 mm) were statistically significantly taller compared to their 1 <italic>g</italic> controls (mean equal to 1.79 mm). The significance level for all the statistical analyses is p &lt; 0.05. Therefore, measurements of the mature stage after life-long exposure to simulated altered gravity show that the final height of the sorocarp is ultimately determined, at least partially, by the gravity environment in which development occurs.</p></abstract>ARTICLE2022-01-17T00:00:00.000+00:00Mammalian Reproduction and Development on the International Space Station (ISS): Proceedings of the Rodent Mark III Habitat Workshop<abstract><title style='display:none'>ABSTRACT</title><p>The <italic>Mark III Rodent Habitat Workshop</italic> was held at NASA Ames Research Center on March 21-22, 2013 to prepare top-level science requirements for developing a habitat to support studies of mammalian reproduction and development on the International Space Station (ISS). This timely workshop assembled a diverse team with expertise in reproductive and developmental biology, behavior, space biosciences, habitat development, physiology, mouse genetics, veterinary medicine, rodent husbandry, flight hardware development (rodent), and spaceflight operations. Participants received overview presentations from each discipline, discussed concerns, potential risks, and risk mitigations corresponding to distinctive reproductive and developmental phases, and reviewed specific examples of research within the major space bioscience disciplines requiring a Mark III habitat<sup><xref ref-type="fn" rid="j_gsr-2013-0009_fn_001">1</xref></sup> to achieve their objectives. In this review, we present the workshop materials and products, and summarize major recommendations for defining the requirements envelope for the NASA Rodent Habitat (RH) Mark III. Development of this habitat will permit the first long duration studies of mammalian reproduction and development in space, within and across generations.</p></abstract>ARTICLE2022-01-17T00:00:00.000+00:00A Computational Study of the Mechanics of Gravity-induced Torque on Cells<abstract><title style='display:none'>ABSTRACT</title><p>In this paper we use Nace’s previous work in order to model the effects of gravity in cells and similar objects. In the presence of the gravitational field of a primary body, the gravity vector can result in numerous effects, some of which are tension, shear, and finally torque. To model the torque effect we use a complete expression for the gravitational acceleration, as this is given on the surface of a planetary body as well as in orbit around it. In particular, on the surface of the Earth the acceleration is corrected for the effect of oblateness and rotation. In the gravitational acceleration the effect of oblateness can be modeled with the inclusion of a term that contains the <italic>J</italic><sub>2</sub> harmonic coefficient, as well as a term that depends on the square of angular velocity of the Earth. In orbit the acceleration of gravity at the point of the spacecraft is a function of the orbital elements and includes, only in our case, the <italic>J</italic><sub>2</sub> harmonic since no Coriolis force is felt by the spacecraft. We derive analytical expressions and calculate the resulting torque effects for various geocentric latitudes, as well as circular and elliptical orbits of various eccentricities and inclinations. We find that elliptical polar orbits result in higher torques, and that higher eccentricities result in higher the torque effects. To any measurable extent, our results do not drastically impact any existing biophysical conclusions.</p></abstract>ARTICLE2022-01-17T00:00:00.000+00:00Preliminary Species and Media Selection for the Veggie Space Hardware<abstract><title style='display:none'>ABSTRACT</title><p>Plants will be an important component of off-Earth life support systems for food production and atmosphere recycling. “Veggie” is a small vegetable production unit designed for space flight, with a passive water delivery system. Plants can be grown in Veggie using small bags with a wicking surface containing media and fertilizer, i.e., pillows. Pillows planted with seeds can be placed on the wicking surface of the Veggie reservoir and water will wick throughout the media. Multiple small salad and herb species were grown in Veggie analog conditions using both commercial peat-based media and arcillite. Biometric measurements and microbial loads were assessed. Some species grew better in a particular media, but no general trends were apparent. Lettuce plants grew best in the blends of the peat-based and arcillite media. Microbial counts were lower on plants grown in arcillite. Four media types (peat-based mix, arcillite, and blends of the two) were tested in the rooting pillows; tests included Chinese cabbage, Swiss chard, lettuce, snow pea, and radish. Most species grew best in blends of the commercial mix and arcillite. Edible biomass production varied from 3.5-8 grams dry mass/m<sup>2</sup>/day with lettuce having the lowest biomass and Chinese cabbage highest. Radish plants showed an increasing percentage of partitioning to edible roots with increasing arcillite in the media. Pillows appear to offer a simple, effective strategy for containing rooting media and avoiding free water while growing plants in the Veggie hardware.</p></abstract>ARTICLE2022-01-17T00:00:00.000+00:00The Effects of Spaceflight on Mucin Production in the Mouse Uterus<abstract><title style='display:none'>ABSTRACT</title><p>The effects of microgravity on biological tissues are relatively unexplored, especially in regard to the mammalian female reproductive system. To begin to address this issue, the uterine tissue of female mice flown on NASA shuttle mission STS-118 was studied. Three sets of female mice, each consisting of 12 animals, were utilized in this study: flight animals, ground control animals, and baseline animals. The flight animals were housed in the Animal Enclosure Module (AEM) of the Commercial Biomedical Testing Module-2 (CBMT-2), which was a part of the payload of the shuttle’s mid-deck locker. Ground control animals were housed in ground-based AEMs, which were kept in a room specifically designed to mimic the environmental conditions of the flight units with regard to temperature, humidity, and light/dark cycles on a 48 hour delay. Baseline animals were housed in standard rodent cages at ambient temperature and humidity and a 12/12 light/dark cycle. The uterine tissue was stained using an Alcian Blue Periodic Acid Schiff staining procedure and the apical mucin layer thickness was subsequently analyzed. Analysis of the mucin layer in the uterus revealed that the thickness of the mucin layer in the flight tissue was significantly thicker that the mucin layers of the ground control and baseline tissue.</p></abstract>ARTICLE2022-01-17T00:00:00.000+00:00Spaceflight Effects and Molecular Responses in the Mouse Eye: Preliminary Observations After Shuttle Mission STS-133<abstract><title style='display:none'>ABSTRACT</title><p>Spaceflight exploration presents environmental stressors including microgravity-induced cephalad fluid shift and radiation exposure. Ocular changes leading to visual impairment in astronauts are of occupational health relevance. The effect of this complex environment on ocular morphology and function is poorly understood. Female 10-12 week-old BALB/cJ mice were assigned to a flight (FLT) group flown on shuttle mission STS-133, Animal Enclosure Module ground control group (AEM), or vivarium-housed (VIV) ground controls. Eyes were collected at 1, 5, and 7 days after landing and were fixed for histological sectioning. The contralateral eye was used for gene expression profiling by RT-qPCR. Sections were visualized by hematoxylin/eosin stain and processed for 8-hydroxy-2’-deoxyguanosine (8-OHdG), caspase-3, and glial fibrillary acidic protein (GFAP) and β-amyloid double-staining. 8-OHdG and caspase-3 immunoreactivity was increased in the retina in FLT samples at return from flight (R+1) compared to ground controls, and decreased at day 7 (R+7). β-amyloid was seen in the nerve fibers at the post-laminar region of the optic nerve in the flight samples (R+7). Expression of oxidative and cellular stress response genes was upregulated in the retina of FLT samples upon landing, followed by lower levels by R+7. These results suggest that reversible molecular damage occurs in the retina of mice exposed to spaceflight and that protective cellular pathways are induced in the retina and optic nerve in response to these changes.</p></abstract>ARTICLE2022-01-17T00:00:00.000+00:00Effects of Underwater Arm-Cranking Exercise on Cardiac Autonomic Nervous Activity<abstract><title style='display:none'>ABSTRACT</title><p>The purpose of this study was to clarify the beneficial effect of an underwater environment on heart rate (HR) and cardiac autonomic nervous activity (HF) during arm-cranking exercise. Ten healthy young men participated in this study. The arm-cranking exercise (40% peakV̇O<sub>2</sub>) was performed for 10 minutes under two conditions: in water and in air. After the exercise, a recovery phase for 30 seconds followed. Changes in HR, V̇O<sub>2</sub>, and HF did not differ between the conditions. The time constant of the heart rate decay for the first 30 seconds after exercise in the water was less than in air. The results suggest that cardiac parasympathetic nervous activity influences earlier recovery of HR after exercise in water. The results of our study suggest underwater exercise may be applied to wider areas of health management for individuals returning from space travel or sedentary patients in simulated microgravity environments.</p></abstract>ARTICLE2022-01-17T00:00:00.000+00:00Protective ability of lead corrosion products in indoor atmosphere with acetic acid vapours<abstract> <title style='display:none'>Abstract</title> <p>Lead corrosion products can undergo certain changes over the time in terms of composition. How these changes affect the corrosion of the underlying lead is an important question for protection of historical lead artefacts. In this work, we focus on characterization of changes in composition of lead corrosion products and how the composition affects corrosion of the lead substrate. Prepared model corrosion products on lead coupons were exposed to air at different relative humidity and concertation of acetic acid vapours. Composition of the corrosion products was analysed by XRD and corrosion rate was calculated from gravimetric data. Measurement of polarization resistance was implemented to get more insight into the protective ability of formate corrosion products. With lead formate covering the surface, the corrosion rate of lead coupons was minimal even in humid air with 400 ppb of acetic acid vapours. Acetic acid was however able to alter lead carbonate corrosion products resulting in increased corrosion rate.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Indoor corrosivity classification based on lead coupons<abstract> <title style='display:none'>Abstract</title> <p>Air pollution in museums, libraries, churches, and other indoor environments of cultural heritage objects was studied since 1980s. For classification of corrosivity for such type of indoor environments the ISO 11844 series was developed in 2006. In 2020 the revision of this ISO 11844 series had been finished, where lead was included as standard specimen with high sensitivity to vapour organic acids. This paper gives results of exposure of lead standard coupons in museums and other similar indoor environments together with measurement of climatic parameters and air pollution to verify the new approach.</p> </abstract>ARTICLE2021-12-30T00:00:00.000+00:00Validation of Assays for Reactive Oxygen Species and Glutathione in during Microgravity Simulation<abstract><title style='display:none'>ABSTRACT</title><p>The effects of spaceflight on yeast have high concordance with agents that induce a very low intracellular redox state and induce a massive efflux of glutathione. These results raise important issues. Can the reduced redox state during spaceflight be reproduced and modulated in ground-based simulations? Will this allow definition of unique drug pathways as a low redox potential state mirrors the electrophilic properties of mitochondria where many drugs are metabolized? Unfortunately, assays for redox status and its major cellular determinant—glutathione—are diverse and often cell-type-specific. Currently, an accepted redox probe set for yeast studies is not available. This paper validates fluorescent probes for glutathione and reactive oxygen status in yeast to support mechanistic studies of microgravity and drug metabolism. The plethora of fluorescent reagents for reactive oxygen species and glutathione makes head-to-head comparisons of all the alternatives impractical. These reagents measure the physiological milieu of reactive oxygen species and diverse thiols, rather than specific individual molecules. We report that in yeast, monochlorobimane (mBCL) and 2’,7’-dichlorodihydrofluorescein diacetate (DC-FDA) are suitable for fluorometric and flow cytometry studies of glutathione and reactive oxygen species, respectively. Both dyes have low background fluorescence, predictable loading, good retention, and are not acutely toxic to <italic>Saccharomyces cerevisiae</italic>. Both dyes show concordance with other fluorescent and biochemical assays of reactive oxygen species.</p></abstract>ARTICLE2022-01-19T00:00:00.000+00:00Microarray Identifies Transcription Factors Potentially Involved in Gravitropic Signal Transduction in Arabidopsis<abstract><title style='display:none'>ABSTRACT</title><p>Gravity is a fundamental stimulus that affects plant growth and development. The gravity persistent signal (GPS) treatment uses a cold treatment to isolate the events of signal transduction. Plants are reoriented horizontally in the dark at 4°C for 1 hour and then returned to vertical at room temperature. A gene expression microarray was designed to identify genes that are regulated during the GPS treatment. <italic>Arabidopsis thaliana</italic> var. Columbia was grown to maturity with inflorescence stems of 8-10 cm. Total mRNA was collected from inflorescence stems at 2, 4, 10, and 30 min after reorientation in the cold. cDNA was synthesized from the mRNA and then probed against an Arabidopsis gene expression array with 4 replicates per time point. Analyses presented here focus on transcription factors because of their regulatory functions in response pathways. Five transcription factors (<italic>AtAIB, WRKY18, WRKY26, WRKY33</italic>, and <italic>BT2)</italic> were selected for further study based on their expression at 4 min. Quantitative real-time polymerase chain reaction ((PCR) RT-qPCR) was performed to confirm expression seen in the microarray data. Seeds of Arabidopsis lines containing T-DNA insertions in the genes were obtained, plants bred to homozygosity, and the mutants analyzed for GPS phenotype. Mutant analysis shows significant differences in curvature of inflorescence stems between mutants and wild type.</p></abstract>ARTICLE2022-01-19T00:00:00.000+00:00Mapping by VESGEN of Wing Vein Phenotype in for Quantifying Adaptations to Space Environments<abstract><title style='display:none'>ABSTRACT</title><p>Vascular patterning is a key, genetically responsive phylogenetic classifier of tissues in major organisms flown in space, such as the wings of <italic>Drosophila melanogaster</italic> (the fruit fly), mouse retina, and leaves of <italic>Arabidopsis thaliana</italic>. Phenotypes of increasingly abnormal ectopic wing venation in the highly stereotyped <italic>Drosophila</italic> wing generated by overexpressing the <italic>H-C2</italic> construct of <italic>Notch</italic> antagonist <italic>Hairless</italic> (<xref ref-type="bibr" rid="j_gsr-2015-0011_ref_013">Johannes and Preiss, 2002</xref>) were mapped and quantified by NASA’s VESsel GENeration Analysis (VESGEN) software. By several confirming vascular parameters, the eight stereotyped wing veins remained quite constant in wild type compared to Class 5 <italic>H-C2</italic>, the most perturbed category of the H-C2 overexpression phenotypes. However, ectopic veins increased in number from 1 in the wild type, to 18 in Class 5 <italic>H-C2</italic>. We therefore demonstrate the feasibility of using VESGEN to quantify microscopic images of altered wing venation in <italic>Drosophila melanogaster</italic>. We further determined that several of the signal transduction pathways affecting wing vein patterning were altered by spaceflight, according to gene expression differences observed in our transcriptomic data from a previous shuttle flight experiment. Future studies will help characterize the extent to which these gene expression changes can cause even subtle developmental changes using model organisms, such as <italic>Drosophila</italic>. Therefore, we propose that the sensitive analyses provided by VESGEN software will not only serve as a useful tool to map the genetics of wing vein patterning for terrestrial applications, but also for future phenotypic studies with <italic>Drosophila</italic> for spaceflight missions.</p></abstract>ARTICLE2022-01-19T00:00:00.000+00:00New Insights in Plant Biology Gained from Research in Space<abstract><title style='display:none'>ABSTRACT</title><p>Recent spaceflight experiments have provided many new insights into the role of gravity in plant growth and development. Scientists have been taking seeds and plants into space for decades in an effort to understand how the stressful environment of space affects them. The resultant data have yielded significant advances in the development of advanced life-support systems for long-duration spaceflight and a better understanding of the fundamental role of gravity in directing the growth and development of plants. Experiments have improved as new spaceflight hardware and technology paved the way for progressively more insightful and rigorous plant research in space. The International Space Station (ISS) has provided an opportunity for scientists to both monitor and control their experiments in real-time. Experiments on the ISS have provided valuable insights into endogenous growth responses, light responses, and transcriptomic and proteomic changes that occur in the microgravity environment. In recent years most studies of plants in space have used <italic>Arabidopsis thaliana</italic>, but the single-celled, <italic>Ceratopteris richardii</italic> spore is also a valuable model system that has been used to understand plant gravity response. Experiments using these fern spores have revealed a dynamic and gravity-responsive trans-cell Ca<sup>2+</sup> current that directs polarization of these spores and a possible role of extracellular nucleotides in establishing or contributing to this current. As technology continues to improve, spaceflight experiments will provide many new insights into the role and effects of gravity on plant growth and development.</p></abstract>ARTICLE2022-01-19T00:00:00.000+00:00Compact Heat Rejection System Utilizing Integral Variable Heat Pipe Radiator for Space Application<abstract><title style='display:none'>ABSTRACT</title><p>In order to meet heat rejection requirements for future NASA exploration, scientific, and discovery missions, a study is being conducted for the feasibility of integral variable conductance planar heat pipe (VCPHP) technology. This represents a novel, low technology readiness level (TRL) heat rejection technology that, when developed, could operate efficiently and reliably across a wide range of thermal environments. The concept consists of a planar heat pipe whose evaporator acquires the excess thermal energy from the thermal control system and rejects it at its condenser whose outer surface acts as a radiating surface. The heat pipe is made from thermally conductive polymers in order to minimize its mass. It has a non-condensable gas that changes the active radiator surface depending on the heat load. A mathematical model of steady-state variable conductance heat pipe is developed. Two planar heat pipes are designed, fabricated, and tested to validate the theoretical model. The feasibility of the proposed VCPHP working in a space environment is discussed, based on the model.</p></abstract>ARTICLE2022-01-19T00:00:00.000+00:00Salivary Gland Protein Expression after Bion-M1 and Space Shuttle STS-135 Missions<abstract><title style='display:none'>ABSTRACT</title><p>Secretory proteins produced by salivary glands are stored in granules and released into saliva. Rodent salivary glands are a reliable experimental model because they are morphologically and functionally similar to those of humans. To determine if the effects of microgravity on secretory proteins are increased on extended flights, their expression in mouse parotid glands, morphological, immunocytochemical, and biochemical/molecular methods were employed. Acinar cells of STS-135 (13 day) and Bion-M1 (30 day) flight animals showed an increase of autophagy and apoptosis, while duct cells contained vacuoles with endocytosed proteins. In STS-135, decreases were seen in the regulatory subunit of type II protein kinase A (RII) by Western blotting, and demilune cell and parotid protein (DCPP) and α-amylase (p&lt;0.01) by immunogold labeling, while proline-rich proteins (PRPs, p&lt;0.001) and parotid secretory protein (PSP, p&lt;0.05) were increased. These results suggest microgravity effects on secretion are function-dependent. Microarray analyses showed significant changes in the expression of a number of genes, including components of the cyclic-3’,5’,-adenosine monophosphate (cyclic AMP) signaling pathway. Compared to habitat ground controls, mice from both flights exhibited altered expression of cyclic AMP-specific phosphodiesterases, adenylate cyclase isoforms, and several A-kinase anchoring proteins. Bion-M1 flight mice showed increases in gene expression for lysozyme and amylase, a decrease in PRPs, and RII expression was unchanged from control values. Secretory protein expression is altered by travel in space, representing a reversible adjustment to microgravity conditions. Ultimately, the goal is to develop a test kit using saliva — an easily obtained body fluid — to assess the physiologic effects of travel in space.</p></abstract>ARTICLE2022-01-19T00:00:00.000+00:00Comparative Toxicity of Lunar, Martian Dust Simulants, and Urban Dust in Human Skin Fibroblast Cells<abstract><title style='display:none'>ABSTRACT</title><p>The National Aeronautics and Space Administration (NASA) has plans to further their manned space exploration to Mars and possibly beyond. The potential toxicity of lunar and Martian dusts to astronauts is a big concern. Primary routes of exposure for astronauts are dermal contact, ocular contact, and inhalation. In this study, we focused on dermal contact exposure using human skin cells to investigate the cytotoxic and genotoxic effects of two fractions of lunar dust simulant (JSC-1A-vf, JSC-1A-f) and a Mars dust simulant (Mars-1A), and compared them to urban dust (urban particulate matter), as urban dust toxicity is better understood and thus, provides a good comparison. Our data show the three simulants and urban dust are cytotoxic to human skin cells. The JSC-1A-vf lunar dust simulant is more cytotoxic than the JSC-1A-f and urban dust. Urban dust cytotoxicity is similar to Mars dust simulant after 120 h exposure. All three dust simulants and urban dust show similar low genotoxicity effects. Our data suggest extraterrestrial dust can damage skin cells and may have the potential to be harmful to humans.</p></abstract>ARTICLE2022-01-19T00:00:00.000+00:00Prolonged Head-Down Posture of Bats Induces Remodeling of the Aorta<abstract><title style='display:none'>ABSTRACT</title><p>Inversion is the regular position for bats at rest, but continuous inversion was expected to reverse the gravity vector exposure from feet-ward to head-ward and present hemodynamic challenges that induce remodeling of the aorta. There is paucity of information regarding the cardiovascular structural adaptations in bats engaged in regulating cranial or caudal blood redistribution in prolonged inversion. The aim of this study was to determine aortic adaptations in bats during prolonged inversion. Forty (40) bats were captured at Iwo, Osun State, Nigeria and randomly allocated into a normal control group and three test groups (n=10/group). The inversion period was not extended in control group A, but was maintained 8 days in B, 15 days in C, and 22 days in D. At the end of each inversion period, the bats were euthanized using intramuscular injection, and tissues were processed for Haematoxylin and Eosin, Orcein, and Van Gieson staining. Histological changes in the tunica media and adventitia were quantified, and the results were analyzed statistically. The ascending aorta exhibited thickening of the media and adventitia, whereas the abdominal aorta showed thinning of these regions. The changes increased in magnitude with longer periods of inversion. The histological stains indicated alterations in smooth muscle cells, collagen, and elastin content, consistent with predicted elevated pressure in the ascending and decreased pressure in the abdominal aortae. The vascular adaptation in bats may provide insights into suspected cardiovascular changes in astronauts during long-term spaceflight.</p></abstract>ARTICLE2022-01-19T00:00:00.000+00:00The Effects of the Spaceflight Environment on the Vaginal Mucin Layer of the Mouse<abstract><title style='display:none'>ABSTRACT</title><p>It has been well documented that spaceflight has adverse effects on many tissues and systems throughout the body. Although this phenomenon is well documented, relatively little research has been done in the area of the female reproductive system. If spaceflight has harmful effects on the female reproductive system, the migration of the human species into space would be greatly compromised. The purpose of this study was to determine the effects of spaceflight on the thickness of the apical mucin layer in the vaginae of mice, as changes in this layer could have detrimental effects on sperm survival and, therefore, a profound impact on the animal’s ability to reproduce. This study examined the thickness of the vaginal mucin lining from female mice that were exposed to 13 days of spaceflight and their concomitant controls. The tissues were stained using a technique commonly used to localize and analyze mucin varieties. The tissue was qualitatively analyzed for the type of mucin produced (i.e., acidic, neutral, acidic/neutral mixture). Further, the tissue was quantitatively analyzed for the amount of mucins produced by measuring the thickness of the mucin layer. The results of this study indicate that spaceflight causes a thickening of the mucin lining of the vaginal canal. The results further indicate being housed in an Animal Enclosure Module also caused a thickening of the vaginal mucin layer — presumably due to internal cage environmental factors — but this effect was not as pronounced as that seen in the spaceflight mice.</p></abstract>ARTICLE2022-01-19T00:00:00.000+00:00en-us-1