Compatibility testing of spacecraft materials and spacestorable liquid propellants

Compatibility data for aluminum alloy 2219-T87 and titanium alloy Ti-6Al-4V were obtained while these alloys were exposed to both liquid and vapor fluorine and FLOX at -320 F + or -10 F. These data were obtained using a new low cost compatibility method which incorporates totally sealed containers and double dogbone test specimens and propellants in the simultaneous exposure to vapor and liquid phases. The compatibility investigation covered a storage period in excess of one year. Pitting was more severe in the 2219-T87 aluminum alloy than in the Ti-6Al-4V titanium alloy for both fluorine and FLOX exposure. The degree of chemical attack is more severe in the presence of FLOX than in fluorine and phase. The mechanical properties of the two alloys were not affected by storage in either of the two propellants

A plan for a material compatibility program for oxygen difluoride (OF sub 2) and diborane (B sub 2 H sub 2) liquid propellants

Evaluation of metallic and nonmetallic construction material performance and reliability after long storage in OF2 and B2H

Long term storage test of titanium material with liquid fluorine propellant

The compatibility of 6AL-4V Ti with propellant grade GF2 and LF2 at 77 K for up to 3 years was investigated. Titanium double coupons, annealed or heat treated, with 16 or 64 RMS finishes, were immersed in F2 in individual Pyrex capsules and stored under LN2 for 29 and 39 months. Pre and post immersion tests were performed on the propellant and coupons. Chemical analysis of the propellant did not reveal any significant changes due to titanium corrosion. Gravimetric, visual, microscopic, and metallurgical examination with pitting analysis did not reveal gross corrosion of the titanium although pitting appears to be greater after 39 months exposure. The increase in pit size and number raises the possibility of unpredictable crack propagation instability. Fracture toughness tests are necessary to define this possibility

Compatibility testing of spacecraft materials and space-storable liquid propellants

Compatibility measurements were made for aluminum 2219-T87 alloy and titanium 6Al-4V alloy in the presence of liquid fluorine and flox. Results of post test characterization after exposure durations of 61 and 70 weeks are presented. Results of the total test program are analyzed

Evaluation of the stock structure of cobia (Rachycentron canadum) in the southeastern United States by using dart-tag and genetics data

Available tag-recapture and population genetics data for cobia (Rachycentron canadum) in the south-eastern United States were evaluated to provide information on population structure and determine the geographic boundary between stocks in the Gulf of Mexico and the Atlantic Ocean. The movements of 1750 cobia were evaluated on the basis of assigned tagging and recapture zones. Genetic samples from an additional 2796 cobia collected during the presumed spawning season were genotyped at 10 microsatellite loci, and standard population genetic statistical analyses were applied to the resulting sample data set. Tag- recapture results indicate that cobia tagged south of Cape Canaveral, Florida, primarily move between that area and the Gulf of Mexico and that cobia tagged north of Georgia have little interaction with the area south of Cape Canaveral. Cobia tagged at Cape Canaveral distributed widely throughout the entire southeastern coast of the United States. Genetic analysis results agree, indicating separate stocks that occur from Texas through Hobe Sound on the east coast of Florida and from Savannah, Georgia, to the Chesapeake Bay in Virgina, with distinct genetic groupings within the Atlantic Ocean stock. The results indicate a transition area that occurs from Cape Canaveral through northern Georgia, and additional data from this region are necessary to further refine the stock boundary

Ulcerative colitis mucosal transcriptomes reveal mitochondriopathy and personalized mechanisms underlying disease severity and treatment response

© 2019, The Author(s). Molecular mechanisms driving disease course and response to therapy in ulcerative colitis (UC) are not well understood. Here, we use RNAseq to define pre-treatment rectal gene expression, and fecal microbiota profiles, in 206 pediatric UC patients receiving standardised therapy. We validate our key findings in adult and paediatric UC cohorts of 408 participants. We observe a marked suppression of mitochondrial genes and function across cohorts in active UC, and that increasing disease severity is notable for enrichment of adenoma/adenocarcinoma and innate immune genes. A subset of severity genes improves prediction of corticosteroid-induced remission in the discovery cohort; this gene signature is also associated with response to anti-TNFα and anti-α 4 β 7 integrin in adults. The severity and therapeutic response gene signatures were in turn associated with shifts in microbes previously implicated in mucosal homeostasis. Our data provide insights into UC pathogenesis, and may prioritise future therapies for nonresponders to current approaches

Quantum Big Bang without fine-tuning in a toy-model

The question of possible physics before Big Bang (or after Big Crunch) is addressed via a schematic non-covariant simulation of the loss of observability of the Universe. Our model is drastically simplified by the reduction of its degrees of freedom to the mere finite number. The Hilbert space of states is then allowed time-dependent and singular at the critical time $t=t_c$. This option circumvents several traditional theoretical difficulties in a way illustrated via solvable examples. In particular, the unitary evolution of our toy-model quantum Universe is shown interruptible, without any fine-tuning, at the instant of its bang or collapse $t= t_c$.Comment: 20 pp., 1 fig., invited talk for the conference "10th Workshop on Quantization, Dualities and Integrable Systems" (April 22 - 24, 2011), http://qdis.emu.edu.tr/index.htm

Population genetics of Cobia (Rachycentron canadum): implications for fishery management along the coast of the southeastern United States

Cobia (Rachycentron canadum) is a pelagic, migratory species with a transoceanic distribution in tropical and subtropical waters. Recreational fishing pressure on Cobia in the United States has increased substantially during the last decade, especially in areas of its annual inshore aggregations, making this species potentially susceptible to overfishing. Although Cobia along the Atlantic and Gulf coasts of the southeastern United States are currently managed as a single fishery, the genetic composition of Cobias in these areas is unclear. On the basis of a robust microsatellite data set from collections along the U.S. Atlantic coast (2008–09), offshore groups were genetically homogenous. However, the 2 sampled inshore aggregations (South Carolina and Virginia) were genetically distinct from each other, as well as from the offshore group. The recapture of stocked fish within their release estuary 2 years after release indicates that some degree of estuarine fidelity occurs within these inshore aggregations and supports the detection of their unique genetic structure at the population level. These results complement the observed high site fidelity of Cobias in South Carolina and support a recent study that confirms that Cobia spawn in the inshore aggregations. Our increased understanding of Cobia life history will be beneficial for determining the appropriate scale of fishery management for Cobia

Tag-reporting levels for red drum (Sciaenops ocellatus) caught by anglers in South Carolina and Georgia estuaries

A total of 1784 legal-size (≥356 mm TL) hatchery-produced red drum (Sciaenops ocellatus) were tagged and released to estimate tag-reporting levels of recreational anglers in South Carolina (SC) and Georgia (GA). Twelve groups of legal-size fish (~150 fish/ group) were released. Half of the fish of each group were tagged with an external tag with the message “reward” and the other half of the fish were implanted with tags with the message “$100 reward.” These fish were released into two estuaries in each state (n=4); three replicate groups were released at different sites within each estuary (n=12). From results obtained in previous tag return experiments conducted by wildlife and fisheries biologists, it was hypothesized that reporting would be maximized at a reward level of$100/tag. Reporting level for the “reward”tags was estimated by dividing the number of “reward” tags returned by the number of “$100 reward” tags returned. The cumulative return level for both tag messages was 22.7 (±1.9)$100 reward” tags were returned. This finding indicates that only 56.7% of the fish captured with “reward” tags were reported in SC. The pattern was similar for GA where 19.1 (±10.6)% of “reward” message tags were returned as compared with 30.1 (±15.6)% for “$100 reward” message tags. This difference yielded a reporting level of 63% for “reward” tags in GA. Currently, 50% is used as the estimate for the angler reporting level in population models for red drum and a number of other coastal finfish species in the South Atlantic region of the United States. Based on results of our study, the commonly used reporting estimate may result in an overestimate of angler exploitation for red drum

Long ncRNA Landscape in the Ileum of Treatment-Naive Early-Onset Crohn Disease.

Long noncoding RNAs (lncRNA) are key regulators of gene transcription and many show tissue-specific expression. We previously defined a novel inflammatory and metabolic ileal gene signature in treatment-naive pediatric Crohn disease (CD). We now extend our analyses to include potential regulatory lncRNA.Using RNAseq, we systematically profiled lncRNAs and protein-coding gene expression in 177 ileal biopsies. Co-expression analysis was used to identify functions and tissue-specific expression. RNA in situ hybridization was used to validate expression. Real-time polymerase chain reaction was used to test lncRNA regulation by IL-1β in Caco-2 enterocytes.We characterize widespread dysregulation of 459 lncRNAs in the ileum of CD patients. Using only the lncRNA in discovery and independent validation cohorts showed patient classification as accurate as the protein-coding genes, linking lncRNA to CD pathogenesis. Co-expression and functional annotation enrichment analyses across several tissues and cell types 1showed that the upregulated LINC01272 is associated with a myeloid pro-inflammatory signature, whereas the downregulated HNF4A-AS1 exhibits association with an epithelial metabolic signature. We confirmed tissue-specific expression in biopsies using in situ hybridization, and validated regulation of prioritized lncRNA upon IL-1β exposure in differentiated Caco-2 cells. Finally, we identified significant correlations between LINC01272 and HNF4A-AS1 expression and more severe mucosal injury.We systematically define differentially expressed lncRNA in the ileum of newly diagnosed pediatric CD. We show lncRNA utility to correctly classify disease or healthy states and demonstrate their regulation in response to an inflammatory signal. These lncRNAs, after mechanistic exploration, may serve as potential new tissue-specific targets for RNA-based interventions