Oxygen Generation Assembly Design for Exploration Missions

Future Exploration missions will require an Oxygen Generation Assembly (OGA) to electrolyze water to supply oxygen for crew metabolic consumption. The system design will be based on the International Space Station (ISS) OGA but with added improvements based on lessons learned during ISS operations. These improvements will reduce system weight, crew maintenance time and resupply mass from Earth while increasing reliability. Currently, the design team is investigating the feasibility of the upgrades by performing ground tests and analyses. Upgrades being considered include: redesign of the electrolysis cell stack, deletion of the hydrogen dome, replacement of the hydrogen sensors, deletion of the wastewater interface, redesign of the recirculation loop deionizing bed and redesign of the cell stack Power Supply Module. The upgrades will be first demonstrated on the ISS OGA

Advanced Oxygen Generation Assembly for Exploration Missions

Future Exploration missions will require an Oxygen Generation Assembly (OGA) to electrolyze water to supply oxygen for crew metabolic consumption. The system design will be based on the International Space Station (ISS) OGA but with added improvements based on lessons learned during ISS operations and technological advances since the original OGA was designed and built. These improvements will reduce system weight, crew maintenance time and spares mass while increasing reliability. Currently, the design team is investigating the feasibility of the upgrades by performing ground tests and analyses. Upgrades being considered include: redesign of the electrolysis cell stack, deletion of the hydrogen dome, replacement of the hydrogen sensors, deletion of the wastewater interface, redesign of the recirculation loop deionizing bed and redesign of the cell stack Power Supply Module. The upgrades will be first demonstrated on the ISS OGA

Advancing the Oxygen Generation Assembly Design to Increase Reliability and Reduce Costs for a Future Long Duration Mission

The state-of-the-art Oxygen Generation Assembly (OGA) has been reliably producing breathing oxygen for the crew aboard the International Space Station (ISS) for over eight years. Lessons learned from operating the ISS OGA have led to proposing incremental improvements to advance the baseline design for use in a future long duration mission. These improvements are intended to reduce system weight, crew maintenance time and resupply mass from Earth while increasing reliability. The proposed improvements include replacing the cell stack membrane material, deleting the nitrogen purge equipment, replacing the hydrogen sensors, deleting the wastewater interface, replacing the hydrogen dome and redesigning the cell stack power supply. The development work to date will be discussed and forward work will be outlined. Additionally, a redesigned system architecture will be proposed

Microbial Challenge Testing of Single Liquid Cathode Feed Water Electrolysis Cells for the International Space Station (ISS) Oxygen Generator Assembly (OGA)

The International Space Station (ISS) Oxygen Generator Assembly (OGA) operational performance may be adversely impacted by microbiological growth and biofilm formation over the electrolysis cell membranes. Biofilms could hinder the transport of water from the bulk fluid stream to the membranes and increase the cell resistance resulting in higher cell voltages and a shorter cell life. A microbial challenge test was performed on duplicate single liquid cathode feed electrolyzer cells to evaluate operational performance with increasing levels of a mixture of five bacteria isolated from ISS and Space Shuttle potable water systems. Baseline performance of the single water electrolysis cells was determined for approximately one month with deionized water. Monthly performance was also determined following each inoculation of the feed tank with 100, 1000, 10,000 and 100,000 cells/ml of the mixed suspension of test bacteria. Water samples from the feed tank and recirculating water loops for each cell were periodically analyzed for enumeration and speciation of bacteria and total organic carbon. While initially a concern, this test program has demonstrated that the performance of the electrolysis cell is not adversely impacted by feed water containing the five species of bacteria tested at a concentration measured as high as 1,000,000 colony forming units (CFU)/ml. This paper presents the methodologies used in the conduct of this test program along with the performance test results at each level of bacteria concentration

Biological Signature of Scotian Shelf Water Crossovers on Georges Bank During Spring 1997

Episodic crossovers of cold low salinity Scotian Shelf Water (SSW) onto the Northeast Peak of Georges Bank are a potentially important mechanism transporting plankton species, including the copepod Calanus finmarchicus and its prey and predators, onto the Bank each spring. We provide the first detailed investigation of horizontal and vertical zooplankton distributions in SSW crossovers compared to other onbank locations from three GLOBEC cruises during spring 1997. SSW crossovers are physically and biologically distinct from other Bank locations. In late spring, chlorophyll concentrations and in vivo fluorescence are elevated and light transmission is reduced in SSW, while during early spring, these parameters are more variable. SSW communities do not contain a unique zooplankton assemblage or indicator species but instead show differences in abundance and life history parameters for various taxa compared to other Bank locations. SSW has high abundances of young C. finmarchicus life history stages, almost no diel vertical migration of zooplankton, low abundances of invertebrate predators, and low fish egg abundance. Population development of C. finmarchicus in SSW lags that in adjacent water. The potential biological impact of SSW crossovers on Georges Bank varies seasonally. In April, density inversions and interleaving of SSW and non‐SSW suggest active mixing, resulting in similar community composition of SSW and adjacent non‐SSW. SSW crossovers are probably an important source to Georges Bank of young stages of C. finmarchicus in early spring. In May, after stratification strengthens, the greater differentiation between SSW plankton and elsewhere indicates that mixing between communities is more limited

Global alterations to the choroid plexus blood-CSF barrier in amyotrophic lateral sclerosis

© 2020 The Author(s). The choroid plexus (CP) is a highly vascularized structure located in the ventricles that forms the blood-CSF barrier (BCSFB) and separates the blood from the cerebrospinal fluid (CSF). In addition to its role as a physical barrier, the CP functions in CSF secretion, transport of nutrients into the central nervous system (CNS) and a gated point of entry of circulating immune cells into the CNS. Aging and neurodegeneration have been reported to affect CP morphology and function and increase protein leakage from blood to the CSF. Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease associated with both upper and lower motor neuron loss, as well as altered proteomic and metabolomic signatures in the CSF. The role of the BCSFB and the CP in ALS is unknown. Here we describe a transcriptomic and ultrastructural analysis of BCSFB and CP alterations in human postmortem tissues from ALS and non-neurologic disease controls. ALS-CP exhibited widespread disruptions in tight junctional components of the CP epithelial layer and vascular integrity. In addition, we detected loss of pericytes around ALS blood vessels, accompanied by activation of platelet aggregation markers vWF and Fibrinogen, reminiscent of vascular injury. To investigate the immune component of ALS-CP, we conducted a comprehensive analysis of cytokines and chemokine panels in CP lysates and found a significant down-regulation of M-CSF and V-CAM1 in ALS, as well as up-regulation of VEGF-A protein. This phenotype was accompanied by an infiltration of MERTK positive macrophages into the parenchyma of the ALS-CP when compared to controls. Taken together, we demonstrate widespread structural and functional disruptions of the BCSFB in human ALS increasing our understanding of the disease pathology and identifying potential new targets for ALS therapeutic development

Beef cows and calves, 1979: a summary of research

Response of fall-born calves to monensin on orchardgrass / alfalfa or tall fescue / alfalfa pastures / F. M. Byers, C. F. Parker, and R. W. Van Keuren -- Effects of forage system and breed type on the performance of fall calving cows / C. F. Parker and R. W. Van Keuren -- Forage management for beef production / R. W. Van Keuren, C. F. Parker, and E. W. Klosterman -- Breeding and management systems to optimize beef breeding herd productivity / E. W. Klosterman, R. W. Van Keuren, C. F. Parker, and F. M. Byers -- Voluntary feed intake of mature cows as related to breed type, condition, and forage quality / E. W. Klosterman, F. M. Byers, and C. F. Parker -- Weight and condition changes of pregnant beef cows wintered on corn stover stacks / G. R. Wilson, J. G. Gordon, J. H. Cline, K. M. Irvin, and E. W. Klosterman -- Estrus synchronization of beef cows and heifers with prostaglandin F2a under field conditions / G. R. Wilson, T. L. Benecke, K. M. Irvin, T. M. Ludwick, C. E. Marshall, and R. A. Wallac

Loss of Omi mitochondrial protease activity causes the neuromuscular disorder of mnd2 mutant mice

The mouse mutant mnd2 (motor neuron degeneration 2) exhibits muscle wasting, neurodegeneration, involution of the spleen and thymus, and death by 40 days of age(1,2). Degeneration of striatal neurons, with astrogliosis and microglia activation, begins at around 3 weeks of age, and other neurons are affected at later stages'. Here we have identified the mnd2 mutation as the missense mutation Ser276Cys in the protease domain of the nuclear-encoded mitochondrial serine protease Omi (also known as HtrA2 or Prss25). Protease activity of Omi is greatly reduced in tissues of mnd2 mice but is restored in mice rescued by a bacterial artificial chromosome transgene containing the wildtype Omi gene. Deletion of the PDZ domain partially restores protease activity to the inactive recombinant Omi protein carrying the Ser276Cys mutation, suggesting that the mutation impairs substrate access or binding to the active site pocket. Loss of Omi protease activity increases the susceptibility of mitochondria to induction of the permeability transition, and increases the sensitivity of mouse embryonic fibroblasts to stress-induced cell death. The neurodegeneration and juvenile lethality in mnd2 mice result from this defect in mitochondrial Omi protease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62561/1/nature02052.pd

Fall 1967

Massachusetts Turf and Lawn Grass CouncilBetter Turf Through Research and Educatio