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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1998

Phosphate Biomineralization of Cambrian Microorganisms

As part of a long term study of biological markers (biomarkers), we are documenting a variety of features which reflect the previous presence of living organisms. As we study meteorites and samples returned from Mars, our main clue to recognizing possible microbial material may be the presence of biomarkers rather than the organisms themselves. One class of biomarkers consists of biominerals which have either been precipitated directly by microorganisms, or whose precipitation has been influenced by the organisms. Such microbe-mediated mineral formation may include important clues to the size, shape, and environment of the microorganisms. The process of fossilization or mineralization can cause major changes in morphologies and textures of the original organisms. The study of fossilized terrestrial organisms can help provide insight into the interpretation of mineral biomarkers. This paper describes the results of investigations of microfossils in Cambrian phosphate-rich rocks (phosphorites) that were found in Khubsugul, Northern Mongolia.

McKay, David S.↗
NASA NTRS2001

Sedimentary Parameters Controlling Occurrence and Preservation of Microbial Mats in Siliciclastic Depositional Systems

Shallow-marine, siliciclastic depositional systems are governed by physical sedimentary processes. Mineral precipitation or penecontemporaneous cementation play minor roles. Today, coastal siliciclastic environments may be colonized by a variety of epibenthic, mat-forming cyanobacteria. Studies on microbial mats showed that they are not randomly distributed in modern tidal environments. Distribution and abundancy is mainly function of a particular sedimentary facies. Fine-grained sands composed of "clear" (translucent) quartz particles constitute preferred substrates for cyanobacteria. Mat-builders also favor sites characterized by moderate hydrodynamic flow regimes, which permit biomass enrichment and construction of mat fabrics without lethal burial of mat populations by fine sediments. A comparable facies relationship can be observed in ancient siliciclastic shelf successions from the terminal Neoproterozoic Nama Group, Namibia. Wrinkle structures that record microbial mats are present but sparsely distributed in mid- to inner shelf sandstones of the Nudaus Formation. The sporadic distribution of these structures reflects both the narrow ecological window that governs mat development and the distinctive taphonomic conditions needed to preserve the structures. These observations caution that statements about changing mat abundance across the Proterozoic-Cambrian boundary must be firmly rooted in paleoenvironmental and taphonomic analysis. Understanding the factors that influence the formation and preservation of microbial structures in siliciclastic regimes can facilitate exploration for biological signatures in Earth's oldest rocks. Moreover, insofar as these structures can be preserved on bedding surfaces and are not easily mimicked by physical processes, they constitute a set of biological markers that can be searched for on Mars by remotely controlled rovers.

Noffke, Nora↗
NASA NTRS1994

A molecular and isotopic study of the organic matter from the Paris Basin, France

Thirteen Liassic sedimentary rocks of increasing depth and three petroleums from the Paris Basin were studied for 13C/12C isotopic compositions and biological markers, including steranes, sterenes, methylphenanthrenes, methylanthracenes, and triaromatic steroids. The isotopic compositions of n-alkanes from mature sedimentary rocks and petroleums fall in a narrow range (2%), except for the deepest Hettangian rock and the Trias petroleum, for which the short-chain n-alkanes are enriched and depleted in 13C, respectively. Most of the molecular parameters increase over the 2000-2500 m depth range, reflecting the transformation of the organic matter at the onset of petroleum generation. In this zone, carbonate content and carbon isotopic composition of carbonates, as well as molecular parameters, are distinct for the Toarcian and Hettangian source rocks and suggest a migration of organic matter from these two formations. Two novel molecular parameters were defined for this task: one using methyltriaromatic steroids from organic extracts; the other using 1-methylphenanthrene and 2-methylanthracene from kerogen pyrolysates. The anomalous high maturity of the Dogger petroleum relative to the maturity-depth trend of the source rocks is used to estimate the minimal vertical distance of migration of the organic matter from the source rock to the reservoir.

Non-NASA Center↗
NASA NTRS1999

Alterations in endogenous circadian rhythm of core temperature in senescent Fischer 344 rats

We assessed whether alterations in endogenous circadian rhythm of core temperature (CRT) in aging rats are associated with chronological time or with a biological marker of senescence, i.e., spontaneous rapid body weight loss. CRT was measured in male Fischer 344 (F344) rats beginning at age 689 days and then continuously until death. Young rats were also monitored. The rats were housed under constant dim red light at 24-26 degrees C, and core temperature was recorded every 10 min via biotelemetry. The CRT amplitude of the body weight-stable (presenescent) old rats was significantly less than that of young rats at all analysis periods. At the onset of spontaneous rapid weight loss (senescence), all measures of endogenous CRT differed significantly from those in the presenescent period. The suprachiasmatic nucleus (a circadian pacemaker) of the senescent rats maintained its light responsiveness as determined by an increase in c-fos expression after a brief light exposure. These data demonstrate that some characteristics of the CRT are altered slowly with chronological aging, whereas others occur rapidly with the onset of senescence.

Non-NASA Center↗
NASA NTRS1997

The parathyroid hormone circadian rhythm is truly endogenous--a general clinical research center study

While circulating levels of PTH follow a diurnal pattern, it has been unclear whether these changes are truly endogenous or are dictated by external factors that themselves follow a diurnal pattern, such as sleep-wake cycles, light-dark cycles, meals, or posture. We evaluated the diurnal rhythm of PTH in 11 normal healthy male volunteers in our Intensive Physiologic Monitoring Unit. The first 36 h spent under baseline conditions were followed by 28-40 h of constant routine conditions (CR; enforced wakefulness in the strict semirecumbent position, with the consumption of hourly snacks). During baseline conditions, PTH levels followed a bimodal diurnal rhythm with an average amplitude of 4.2 pg/mL. A primary peak (t1max) occurred at 0314 h, and the secondary peak (t2max) occurred at 1726 h, whereas the primary and secondary nadirs (t1min and t2min) took place, on the average, at 1041 and 2103 h, respectively. This rhythm was preserved under CR conditions, albeit with different characteristics, thus confirming its endogenous nature. The serum ionized calcium (Cai) demonstrated a rhythm in 3 of the 5 subjects studied that varied widely between individuals and did not have any apparent relation to PTH. Urinary calcium/creatinine (UCa/Cr), phosphate/Cr (UPO4/Cr), and sodium/Cr (UNa/Cr) ratios all followed a diurnal rhythm during the baseline day. These rhythms persisted during the CR, although with different characteristics for the first two parameters, whereas that of UNa/Cr was unchanged. In general, the temporal pattern for the UCa/Cr curve was a mirror image of the PTH curve, whereas the UPO4/Cr pattern moved in parallel with the PTH curve. In conclusion, PTH levels exhibit a diurnal rhythm that persists during a CR, thereby confirming that a large component of this rhythm is an endogenous circadian rhythm. The clinical relevance of this rhythm is reflected in the associated rhythms of biological markers of PTH effect at the kidney, namely UCa/Cr and UPO4/Cr.

NASA Discipline Musculoskeletal↗
NASA NTRS2006

Ultrasonic/Sonic Driller/Corer (USDC) as a Subsurface Sampler and Sensors Platform for Planetary Exploration Applications

The search for existing or past life in the Universe is one of the most important objectives of NASA's mission. For this purpose, effective instruments that can sample and conduct in-situ astrobiology analysis are being developed. In support of this objective, a series of novel mechanisms that are driven by an Ultrasonic/Sonic actuator have been developed to probe and sample rocks, ice and soil. This mechanism is driven by an ultrasonic piezoelectric actuator that impacts a bit at sonic frequencies through the use of an intermediate free-mass. Ultrasonic/Sonic Driller/Corer (USDC) devices were made that can produce both core and powdered cuttings, operate as a sounder to emit elastic waves and serve as a platform for sensors. For planetary exploration, this mechanism has the important advantage of requiring low axial force, virtually no torque, and can be duty cycled for operation at low average power. The advantage of requiring low axial load allows overcoming a major limitation of planetary sampling in low gravity environments or when operating from lightweight robots and rovers. The ability to operate at duty cycling with low average power produces a minimum temperature rise allowing for control of the sample integrity and preventing damage to potential biological markers in the acquired sample. The development of the USDC is being pursued on various fronts ranging from analytical modeling to mechanisms improvements while considering a wide range of potential applications. While developing the analytical capability to predict and optimize its performance, efforts are made to enhance its capability to drill at higher power and high speed. Taking advantage of the fact that the bit does not require rotation, sensors (e.g., thermocouple and fiberoptics) were integrated into the bit to examine the borehole during drilling. The sounding effect of the drill was used to emit elastic waves in order to evaluate the surface characteristics of rocks. Since the USDC is driven by piezoelectric actuation mechanism it can designed to operate at extreme temperature environments from very cold as on Titan and Europa to very hot as on Venus. In this paper, a review of the latest development and applications of the USDC will be given.

sampling↗
NASA NTRS2006

'Nano' Morphology and Element Signatures of Early Life on Earth: A New Tool for Assessing Biogenicity

The relatively young technology of NanoSIMS is unlocking an exciting new level of information from organic matter in ancient sediments. We are using this technique to characterize Proterozoic organic material that is clearly biogenic as a guide for interpreting controversial organic structures in either terrestrial or extraterrestrial samples. NanoSIMS is secondary ion mass spectrometry for trace element and isotope analysis at sub-micron resolution. In 2005, Robert et al. [1] combined NanoSIMS element maps with optical microscopic imagery in an effort to develop a new method for assessing biogenicity of Precambrian structures. The ability of NanoSIMS to map simultaneously the distribution of organic elements with a 50 nm spatial resolution provides new biologic markers that could help define the timing of life s development on Earth. The current study corroborates the work of Robert et al. and builds on their study by using NanoSIMS to map C, N (as CN), S, Si and O of both excellently preserved microfossils and less well preserved, non-descript organics in Proterozoic chert from the ca. 0.8 Ga Bitter Springs Formation of Australia.

Oehler, D. Z.↗
NASA NTRS2016

Protective Effect of Pyruvate Against Radiation-Induced Damage in Collagenized Tissues

Exposure to high doses of ionizing radiation produces both acute and late effects on the collagenized tissues and have profound effects on wound healing. Because of the crucial practical importance for new radioprotective agents, our study has been focused on evaluation of the efficacy of non-toxic naturally occurring compounds to protect tissue integrity against high-dose gamma radiation. Here, we demonstrate that molecular integrity of collagen may serve as a sensitive biological marker for quantitative evaluation of molecular damage to collagenized tissue and efficacy of radioprotective agents. Increasing doses of gamma radiation (0-50kGy) result in progressive destruction of the native collagen fibrils, which provide a structural framework, strength, and proper milieu for the regenerating tissue. The strategy used in this study involved the thermodynamic specification of all structural changes in collagenized matrix of skin, aortic heart valve, and bone tissue induced by different doses and conditions of g-irradiation. This study describes a simple biophysical approach utilizing the Differential Scanning Calorimetry (DSC) to characterize the structural resistance of the aortic valve matrix exposed to different doses of g-irradiation. It allows us to identify the specific response of each constituent as well as to determine the influence of the different treatments on the characteristic parameters of protein structure. We found that pyruvate, a substance that naturally occurs in the body, provide significant protection (up to 80%) from biochemical and biomechanical damage to the collagenized tissue through the effective targeting of reactive oxygen species. The recently discovered role of pyruvate in the cell antioxidant defense to O2 oxidation, and its essential constituency in the daily human diet, indicate that the administration of pyruvate-based radioprotective formulations may provide safe and effective protection from deleterious effects of ionizing radiation.

Differential Scanning Calorimetry↗
NASA NTRS1996

Lipid biomarkers for bacterial ecosystems: studies of cultured organisms, hydrothermal environments and ancient sediments

This paper forms part of our long-term goal of using molecular structure and carbon isotopic signals preserved as hydrocarbons in ancient sediments to improve understanding of the early evolution of Earth's surface environment. We are particularly concerned with biomarkers which are informative about aerobiosis. Here, we combine bacterial biochemistry with the organic geochemistry of contemporary and ancient hydrothermal ecosystems to construct models for the nature, behaviour and preservation potential of primitive microbial communities. We use a combined molecular and isotopic approach to characterize lipids produced by cultured bacteria and test a variety of culture conditions which affect their biosynthesis. This information is then compared with lipid mixtures isolated from contemporary hot springs and evaluated for the kinds of chemical change that would accompany burial and incorporation into the sedimentary record. In this study we have shown that growth temperature does not appear to alter isotopic fractionation within the lipid classes produced by a methanotropic bacterium. We also found that cultured cyanobacteria biosynthesize diagnostic methylalkanes and dimethylalkanes with the latter only made when growing under low pCO2. In an examination of a microbial mat sample from Octopus Spring, Yellowstone National Park (USA), we could readily identify chemical structures with 13C contents which were diagnostic for the phototrophic organisms such as cyanobacteria and Chloroflexus. We could not, however, find molecular evidence for operation of a methane cycle in the particular mat samples we studied.

NASA Discipline Exobiology↗
NASA NTRS2017

Electrochemical Detection of Biological Catalysts as Signatures of Extant Life

Liquid water is the quintessential ingredient for life. Biochemistry as we know it is not possible without it. There are two places in the Solar System, other than the Earth, where liquid water is known to exist: Europa and Enceladus. Cassini’s recent discovery of Enceladus’ ocean plumes has excited the scientific community about the possibility for liquid sampling and search for life. Characteristics of life are self-sustainability, its ability to evolve, and self-enclosure. To enable these, chemical energy must be utilized, information must be stored, and enclosing membranes must be built. Many of these processes are accomplished with the use of biological catalysts. To search for life in the ocean worlds, detection of biological catalysts serves as a strong marker of biological activity and thus life.

Koehne, J. E.↗
NASA NTRS2003

A New Antibody for Category 1 Biomarker Detection

At least two questions arise in developing a life-detection strategy: What do we look for and what will positive detection tell us? Unfortunately, many 'biomarkers' are not conclusive markers of biology. For example, sugars, amino acids, polycyclic aromatic hydrocarbons (PAH) and certain bacteria-like morphologies can all be produced non-biologically. Inferences of life following the detection of several inconclusive biomarkers in one sample will always be questioned. Although DNA, RNA and proteins are excellent markers of biology, and preserved on Earth for several millions of years, their survival over longer periods of time is low. Ideally, we should target biomarkers which are both stable over time and formed exclusively from biological processes, i.e. a 'category 1' biomarker under the new classification system of Mckay. We have used antibodies to detect category 1 and other biomarkers in rock samples. Extraction takes a few minutes and analysis a few hours. We have presented use of new antibodies to detect hopanes and have shown proof of operation during martian gravity.

Maule, J.↗
DOE OSTI2021

Endothelial surface translocation of mitochondrial PDCE2 involves the non-canonical secretory autophagy pathway: Putative molecular target for radiation-guided drug delivery

Highlights: • Radiation induces ectopic endothelial surface exposure of mitochondrial PDCE2. • PDCE2 translocation is associated with late-stage inhibition of autophagic flux. • Radiation damage overloads the degradative lysosomal pathway of autophagy. • PDCE2 trafficking occurs via autophagosomes and non-canonical secretory autophagy. • Surface PDCE2 provides a novel target for radiation-guided vascular drug delivery. Radiation has been proposed as a priming agent to induce discriminatory luminal biomarkers for vascular targeting and drug delivery in disorders such as brain arteriovenous malformations and cancers. We previously observed ectopic expression of intracellular proteins such as mitochondrial PDCE2 on irradiated endothelium in animal models. In this study we examined the mechanism of PDCE2 trafficking in human endothelial cells to better understand its suitability as a vascular target. Ionizing radiation induced PDCE2 surface localization in association with accumulation of autophagosome markers (L3CB and p62) indicative of late-stage inhibition of autophagic flux. This effect was abolished in the presence of Rapamycin, an autophagy-inducer, but replicated in the presence of Bafilomycin A, an autophagy blocker. PDCE2 co-localized with lysosomal markers of the canonical degradative autophagy pathway in response to radiation but also with recycling endosomes and SNARE proteins responsible for autophagosome-plasma membrane fusion. These findings demonstrate that radiation-induced blockade of autophagic flux stimulates redirection of intracellular molecules such as PDCE2 to the cell surface via a non-canonical secretory autophagy pathway. Intracellular membrane proteins trafficked in this way could provide a unique pool of radiation biomarkers for therapeutic drug delivery.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1998

Regulation of the collagenase-3 receptor and its role in intracellular ligand processing in rat osteoblastic cells

We have previously described a specific, saturable receptor for rat collagenase-3 in the rat osteosarcoma cell line, UMR 106-01. Binding of rat collagenase-3 to this receptor is coupled to the internalization and eventual degradation of the enzyme and correlates with observed extracellular levels of the enzyme. In this study we have shown that decreased binding, internalization, and degradation of 125I-rat collagenase-3 were observed in cells after 24 h of parathyroid hormone treatment; these activities returned to control values after 48 h and were increased substantially (twice control levels) after 96 h of treatment with the hormone. Subcellular fractionation studies to identify the route of uptake and degradation of collagenase-3 localized intracellular accumulation of 125I-rat collagenase-3 initially in Golgi-associated lysosomes and later in secondary lysosomes. Maximal lysosomal accumulation of the radiolabel and stimulation of general lysosomal activity occurred after 72 h of parathyroid hormone treatment. Preventing fusion of endosomes with lysosomes (by temperature shift, colchicine, or monensin) resulted in no internalized 125I-collagenase-3 in either lysosomal fraction. Treatment of UMR cells with the above agents or ammonium chloride decreased excretion of 125I-labeled degradation products of collagenase-3. These experiments demonstrated that degradation of collagenase-3 required receptor-mediated endocytosis and sequential processing by endosomes and lysosomes. Thus, parathyroid hormone regulates the expression and synthesis of collagenase-3 as well as the abundance and functioning of the collagenase-3 receptor and the intracellular degradation of its ligand. The coordinate changes in the secretion of collagenase-3 and expression of the receptor determine the net abundance of the enzyme in the extracellular space.

NASA Discipline Musculoskeletal↗
NASA NTRS2004

Simultaneous measurement of multiple radiation-induced protein expression profiles using the Luminex(TM) system

Space flight results in the exposure of astronauts to a mixed field of radiation composed of energetic particles of varying energies, and biological indicators of space radiation exposure provides a better understanding of the associated long-term health risks. Current methods of biodosimetry have employed the use of cytogenetic analysis for biodosimetry, and more recently the advent of technological progression has led to advanced research in the use of genomic and proteomic expression profiling to simultaneously assess biomarkers of radiation exposure. We describe here the technical advantages of the Luminex(TM) 100 system relative to traditional methods and its potential as a tool to simultaneously profile multiple proteins induced by ionizing radiation. The development of such a bioassay would provide more relevant post-translational dynamics of stress response and will impart important implications in the advancement of space and other radiation contact monitoring. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

NASA Center JSC↗
NASA NTRS1992

Planar induction of anteroposterior pattern in the developing central nervous system of Xenopus laevis

It has long been thought that anteroposterior (A-P) pattern in the vertebrate central nervous system is induced in the embryo's dorsal ectoderm exclusively by signals passing vertically from underlying, patterned dorsal mesoderm. Explants from early gastrulae of the frog Xenopus laevis were prepared in which vertical contact between dorsal ectoderm and mesoderm was prevented but planar contact was maintained. In these, four position-specific neural markers (engrailed-2, Krox-20, XlHbox 1, and XlHbox 6) were expressed in the ectoderm in the same A-P order as in the embryo. Thus, planar signals alone, following a path available in the normal embryo, can induce A-P neural pattern.

NASA Discipline Developmental Biology↗
DOE OSTI2021

MiR-375 silencing attenuates pro-inflammatory macrophage response and foam cell formation by targeting KLF4

Macrophage mediated inflammation and foam cell formation play crucial roles in the development of atherosclerosis. MiR-375 is a small noncoding RNA that significantly implicated in multiple tumor regulation and has been emerged as a novel biomarker for type 2 diabetes. However, the exact role of miR-375 on macrophage activation remains unknown. In the present study, we observed that miR-375 expression showed an up-regulated expression in atherosclerotic aortas, as well as in bone marrow derived macrophages (BMDMs) and mouse peritoneal macrophages (MPMs) isolated from ApoE deficiency mice and was gradually increased followed the Ox-LDL treated time. Functionally, miR-375 inhibition significantly decreased foam cell formation accompanied by up-regulated genes expression involved in cholesterol efflux but reduced genes expression implicated in cholesterol influx. Moreover, miR-375 silencing increased resolving M2 macrophage but reduced pro-inflammatory M1 macrophage markers expression. Such above effects can be reversed by miR-375 overexpression. Mechanistically, we noticed that miR-375 knockdown promoted KLF4 expression which was required for the ameliorated effect of miR-375 silencing on macrophage activation. Importantly, the consistent results in mRNA expression of M1 and M2 markers were observed in vivo, and miR-375{sup −/−}ApoE{sup −/−} mice significant decreased atherosclerotic lesions in the whole aorta and aortic sinus. Taken together, these evidences suggested that miR-375 knockdown attenuated macrophage activation partially through activation of KLF4-dependent mechanism.

60 APPLIED LIFE SCIENCES↗
NASA NTRS2005

Bone Markers, Calcium Metabolism, and Calcium Kinetics During Extended-Duration Space Flight on the Mir Space Station

Bone loss is a current limitation for long-term space exploration. Bone markers, calcitropic hormones, and calcium kinetics of crew members on space missions of 4-6 months were evaluated. Spaceflight-induced bone loss was associated with increased bone resorption and decreased calcium absorption. INTRODUCTION: Bone loss is a significant concern for the health of astronauts on long-duration missions. Defining the time course and mechanism of these changes will aid in developing means to counteract these losses during space flight and will have relevance for other clinical situations that impair weight-bearing activity. MATERIALS AND METHODS: We report here results from two studies conducted during the Shuttle-Mir Science Program. Study 1 was an evaluation of bone and calcium biochemical markers of 13 subjects before and after long-duration (4-6 months) space missions. In study 2, stable calcium isotopes were used to evaluate calcium metabolism in six subjects before, during, and after flight. Relationships between measures of bone turnover, biochemical markers, and calcium kinetics were examined. RESULTS: Pre- and postflight study results confirmed that, after landing, bone resorption was increased, as indicated by increases in urinary calcium (p < 0.05) and collagen cross-links (N-telopeptide, pyridinoline, and deoxypyridinoline were all increased >55% above preflight levels, p < 0.001). Parathyroid hormone and vitamin D metabolites were unchanged at landing. Biochemical markers of bone formation were unchanged at landing, but 2-3 weeks later, both bone-specific alkaline phosphatase and osteocalcin were significantly (p < 0.01) increased above preflight levels. In studies conducted during flight, bone resorption markers were also significantly higher than before flight. The calcium kinetic data also validated that bone resorption was increased during flight compared with preflight values (668 +/- 130 versus 427 +/- 153 mg/day; p < 0.001) and clearly documented that true intestinal calcium absorption was significantly lower during flight compared with preflight values (233 +/- 87 versus 460 +/- 47 mg/day; p < 0.01). Weightlessness had a detrimental effect on the balance in bone turnover such that the daily difference in calcium retention during flight compared with preflight values approached 300 mg/day (-234 +/- 102 versus 63 +/- 75 mg/day; p < 0.01). CONCLUSIONS: These bone marker and calcium kinetic studies indicated that the bone loss that occurs during space flight is a consequence of increased bone resorption and decreased intestinal calcium absorption.

Bone and Bones/metabolism/pathology↗