Low Earth orbital atomic oxygen environmental simulation facility for space materials evaluation

Simulation of low Earth orbit atomic oxygen for accelerated exposure in ground-based facilities is necessary for the durability evaluation of space power system component materials for Space Station Freedom (SSF) and future missions. A facility developed at the National Aeronautics and Space Administrations's (NASA) Lewis Research Center provides accelerated rates of exposure to a directed or scattered oxygen beam, vacuum ultraviolet (VUV) radiation, and offers in-situ optical characterization. The facility utilizes an electron-cyclotron resonance (ECR) plasma source to generate a low energy oxygen beam. Total hemispherical spectral reflectance of samples can be measured in situ over the wavelength range of 250 to 2500 nm. Deuterium lamps provide VUV radiation intensity levels in the 115 to 200 nm range of three to five equivalent suns. Retarding potential analyses show distributed ion energies below 30 electron volts (eV) for the operating conditions most suited for high flux, low energy testing. Peak ion energies are below the sputter threshold energy (approximately 30 eV) of the protective coatings on polymers that are evaluated in the facility, thus allowing long duration exposure without sputter erosion. Neutral species are expected to be at thermal energies of approximately .04 eV to .1 eV. The maximum effective flux level based on polyimide Kapton mass loss is 4.4 x 10 exp 6 atoms/((sq. cm)*s), thus providing a highly accelerated testing capability

The effects of simulated low Earth orbit environments on spacecraft thermal control coatings

Candidate Space Station Freedom radiator coatings including Z-93, YB-71, anodized aluminum and SiO(x) coated silvered Teflon have been characterized for optical properties degradation upon exposure to environments containing atomic oxygen, vacuum ultraviolet (VUV) radiation, and/or silicone contamination. YB-71 coating showed a blue-gray discoloration, which has not been observed in space, upon exposure in atomic oxygen facilities which also provide exaggerated VUV radiation. This is evidence that damage mechanisms occur in these ground laboratory facilities which are different from those which occur in space. Radiator coatings exposed to an electron cyclotron resonance (ECR) atomic oxygen source in the presence of silicone-containing samples showed severe darkening from the intense VUV radiation provided by the ECR and from silicone contamination. Samples exposed to atomic oxygen from the ECR source and to VUV lamps, simultaneously, with in situ reflectance measurement, showed that significantly greater degradation occurred when samples received line-of-site ECR beam exposure than when samples were exposed to atomic oxygen scattered off of quartz surfaces without line-of-site view of the ECR beam. For white paints, exposure to air following atomic oxygen/VUV exposure reversed the darkening due to VUV damage. This illustrates the importance of in situ reflectance measurement

Extreme summer heat in Phoenix, Arizona (USA) under global climate change (2041-2070)

Summer extreme heat events in the arid Phoenix, Arizona (USA) metropolitan region for the period 2041-2070 are projected based on the ensemble of ten climate models from the North American Regional Climate Change Assessment Program for the SRES A2 greenhouse gas emissions scenario by the Intergovernmental Panel on Climate Change. Extreme heat events are identified by measures related to two thresholds of the maximum daily air temperature distribution for the historical reference period 1971-2000. Comparing this reference period to the model ensemble-mean, the frequency of extreme heat events is projected to increase by a factor of six to 1.9 events per summer and the average number of event days per year is projected to increase by a factor of 14. The inter-model range for the average number of EHE days per summer is larger for the projected climate, 10.6 to 42.2 days, than for simulations of the past climate simulations (1.5 to 2.4 days).Projektionen für extreme Hitzeereignisse in den Sommermonaten in Phoenix, Arizona (USA) wurden für den Zeitraum 2041-2070 unter der Annahme des SRES A2 Treibhausgasemissionsszenarios des Intergovernmental Panel on Climate Change erstellt. Dafür wurden Simulationsergebnisse eines Ensembles von zehn Klimamodellen ausgewertet, die im Rahmen des North American Regional Climate Change Assessment Programmes angewendet wurden. Die extremen Hitzeereignisse wurden mit Hilfe von Kriterien bestimmt, die auf Schwellenwerttemperaturen für die maximalen täglichen Lufttemperaturen für die Referenzperiode 1971-2000 beruhen. In der Zukunft versechsfacht sich im Ensemblemittel die Häufigkeit der Extremereignisse (~ 1.9 Ereignisse pro Sommer) im Vergleich zum Referenzzeitraum mit einer vierzehnfachen mittleren Anzahl der Hitzetage pro Sommer. Dabei vergrößert sich die Schwankungsbreite der Modelle bezüglich der mittleren Anzahl der Hitzetage pro Sommer in der Zukunft gegenüber der der Vergangenheit von 1.5-2.4 auf 10.6-42.2

Many Disease-Associated Variants of hTERT Retain High Telomerase Enzymatic Activity

Mutations in the gene for telomerase reverse transcriptase (hTERT) are associated with diseases including dyskeratosis congenita, aplastic anemia, pulmonary fibrosis and cancer. Understanding the molecular basis of these telomerase-associated diseases requires dependable quantitative measurements of telomerase enzyme activity. Furthermore, recent findings that the human POT1-TPP1 chromosome end-binding protein complex stimulates telomerase activity and processivity provide incentive for testing variant telomerases in the presence of these factors. In the present work, we compare multiple disease-associated hTERT variants reconstituted with the RNA subunit hTR in two systems (rabbit reticulocyte lysates and human cell lines) with respect to telomerase enzymatic activity, processivity and activation by telomere proteins. Surprisingly, many of the previously reported disease-associated hTERTalleles give near-normal telomerase enzyme activity. It is possible that a small deficit in telomerase activity is sufficient to cause telomere shortening over many years. Alternatively, mutations may perturb functions such as the recruitment of telomerase to telomeres, which are essential in vivo but not revealed by simple enzyme assays

Localization of Minoxidil Sulfotransferase in Rat Liver and the Outer Root Sheath of Anagen Pelage and Vibrissa Follicles

The precise biochemical mechanism and site(s) of action by which minoxidil stimulates hair growth are not yet clear. Minoxidil sulfate is the active metabolite of minoxidil, with regard to smooth muscle vasodilation and hair growth. Formation of minoxidil sulfate is catalyzed by specific PAPS-dependent sulfotransferase(s) and minoxidil-sulfating activities have been previously reported to be present in liver and hair follicles. One of these minoxidil-sulfating enzymes has been purified from rat liver (rat minoxidil sulfotransferase, MST) and a rabbit anti-MST antibody has been prepared. Using this anti-MST antibody, we have immunohistochernically localized minoxidil sulfotransferase in the liver and anagen hair follicles from rat. In rat pelage and vibrissa follicles, this enzyme is localized within the cytoplasm of epithelial cells in the lower outer root sheath. Although the immunolocalization of MST might not necessarily correlate with the MST activity known to be present in anagen follicles, the results of this study strongly suggest that the lower outer root sheath of the hair follicle may serve as a site for the sulfation of topically applied minoxidil

Genomes and Virulence Factors of Novel Bacterial Pathogens Causing Bleaching Disease in the Marine Red Alga Delisea pulchra

Nautella sp. R11, a member of the marine Roseobacter clade, causes a bleaching disease in the temperate-marine red macroalga, Delisea pulchra. To begin to elucidate the molecular mechanisms underpinning the ability of Nautella sp. R11 to colonize, invade and induce bleaching of D. pulchra, we sequenced and analyzed its genome. The genome encodes several factors such as adhesion mechanisms, systems for the transport of algal metabolites, enzymes that confer resistance to oxidative stress, cytolysins, and global regulatory mechanisms that may allow for the switch of Nautella sp. R11 to a pathogenic lifestyle. Many virulence effectors common in phytopathogenic bacteria are also found in the R11 genome, such as the plant hormone indole acetic acid, cellulose fibrils, succinoglycan and nodulation protein L. Comparative genomics with non-pathogenic Roseobacter strains and a newly identified pathogen, Phaeobacter sp. LSS9, revealed a patchy distribution of putative virulence factors in all genomes, but also led to the identification of a quorum sensing (QS) dependent transcriptional regulator that was unique to pathogenic Roseobacter strains. This observation supports the model that a combination of virulence factors and QS-dependent regulatory mechanisms enables indigenous members of the host alga's epiphytic microbial community to switch to a pathogenic lifestyle, especially under environmental conditions when innate host defence mechanisms are compromised

Effect of charted mental illness on reperfusion therapy in hospitalized patients with an acute myocardial infarction in Florida

Patients with mental illness carry risk factors that predispose them to excess cardiovascular mortality from an acute myocardial infarction (AMI) compared to the general population. The aim of this study was to determine if patients with AMI and charted mental illness (CMI) received less reperfusion therapy following an AMI, compared to AMI patients without CMI in a recent sample population from Florida. A secondary analysis of data was conducted using the Florida Agency for Health Care Administration (FL-AHCA) hospital discharge registry. Adults hospitalized with an AMI from 01/01/2010 to 12/31/2015 were included for the analysis. The dependent variable was administration of reperfusion therapy (thrombolytic, percutaneous coronary intervention [PCI], and coronary artery bypass graft [CABG]), and the independent variable was the presence of CMI (depression, schizophrenia, and bipolar disorder). Multivariate logistic regression models were used to test the association controlling for age, gender, ethnicity, race, health insurance, and comorbidities. The database included 61,614 adults (31.3% women) hospitalized with AMI in Florida. The CMI population comprised of 1036 patients (1.7%) who were on average 5 years younger than non-CMI (60.2 ±12.8 versus 65.2 ±14.1; P \u3c .001). Compared with patients without CMI, patients with CMI had higher proportions of women, governmental health insurance holders, and those with more comorbidities. The adjusted odds ratio indicated that patients with CMI were 30% less likely to receive reperfusion therapy compared with those without CMI (OR = 0.7; 95% CI = 0.6–0.8). Within the AMI population including those with and without CMI, women were 23% less likely to receive therapy than men; blacks were 26% less likely to receive reperfusion therapy than whites; and those holding government health insurances were between 20% and 40% less likely to receive reperfusion therapy than those with private health insurance. Patients with AMI and CMI were statistically significantly less likely to receive reperfusion therapy compared with patients without CMI. These findings highlight the need to implement AMI management care aimed to reduce disparities among medically vulnerable patients (those with CMI, women, blacks, and those with governmental health insurance)

In Vivo Fluorescence-Based Endoscopic Detection of Colon Dysplasia in the Mouse Using a Novel Peptide Probe

Colorectal cancer (CRC) is a major cause of cancer-related deaths in much of the world. Most CRCs arise from pre-malignant (dysplastic) lesions, such as adenomatous polyps, and current endoscopic screening approaches with white light do not detect all dysplastic lesions. Thus, new strategies to identify such lesions, including non-polypoid lesions, are needed. We aim to identify and validate novel peptides that specifically target dysplastic colonic epithelium in vivo. We used phage display to identify a novel peptide that binds to dysplastic colonic mucosa in vivo in a genetically engineered mouse model of colo-rectal tumorigenesis, based on somatic Apc (adenomatous polyposis coli) gene inactivation. Binding was confirmed using confocal microscopy on biopsied adenomas and excised adenomas incubated with peptide ex vivo. Studies of mice where a mutant Kras allele was somatically activated in the colon to generate hyperplastic epithelium were also performed for comparison. Several rounds of in vivo T7 library biopanning isolated a peptide, QPIHPNNM. The fluorescent-labeled peptide bound to dysplastic lesions on endoscopic analysis. Quantitative assessment revealed the fluorescent-labeled peptide (target/background: 2.17±0.61) binds ∼2-fold greater to the colonic adenomas when compared to the control peptide (target/background: 1.14±0.15), p<0.01. The peptide did not bind to the non-dysplastic (hyperplastic) epithelium of the Kras mice. This work is first to image fluorescence-labeled peptide binding in vivo that is specific towards colonic dysplasia on wide-area surveillance. This finding highlights an innovative strategy for targeted detection to localize pre-malignant lesions that can be generalized to the epithelium of hollow organs