Ablation Modeling of Ares-I Upper State Thermal Protection System Using Thermal Desktop

The thermal protection system (TPS) for the Ares-I Upper Stage will be based on Space Transportation System External Tank (ET) and Solid Rocket Booster (SRB) heritage materials. These TPS materials were qualified via hot gas testing that simulated ascent and re-entry aerothermodynamic convective heating environments. From this data, the recession rates due to ablation were characterized and used in thermal modeling for sizing the thickness required to maintain structural substrate temperatures. At Marshall Space Flight Center (MSFC), the in-house code ABL is currently used to predict TPS ablation and substrate temperatures as a FORTRAN application integrated within SINDA/G. This paper describes a comparison of the new ablation utility in Thermal Desktop and SINDA/FLUINT with the heritage ABL code and empirical test data which serves as the validation of the Thermal Desktop software for use on the design of the Ares-I Upper Stage project

Direct binding of phosphatidylglycerol at specific sites modulates desensitization of a ligand-gated ion channel

Pentameric ligand-gated ion channels (pLGICs) are essential determinants of synaptic transmission, and are modulated by specific lipids including anionic phospholipids. The exact modulatory effect of anionic phospholipids in pLGICs and the mechanism of this effect are not well understood. Using native mass spectrometry, coarse-grained molecular dynamics simulations and functional assays, we show that the anionic phospholipid, 1-palmitoyl-2-oleoyl phosphatidylglycerol (POPG), preferentially binds to and stabilizes the pLGIC, Erwinia ligand-gated ion channel (ELIC), and decreases ELIC desensitization. Mutations of five arginines located in the interfacial regions of the transmembrane domain (TMD) reduce POPG binding, and a subset of these mutations increase ELIC desensitization. In contrast, a mutation that decreases ELIC desensitization, increases POPG binding. The results support a mechanism by which POPG stabilizes the open state of ELIC relative to the desensitized state by direct binding at specific sites

Smoke-Free Men: Competing and Connecting to Quit

Purpose: The purpose of this study was to explore gender-related factors that motivate and support men’s smoking reduction and cessation to inform effective men-centered interventions. Approach or Design: Focus group design using a semi-structured interview guide. Setting: Three communities in British Columbia, Canada. Participants: A total of 56 men who currently smoked and were interested in reducing or quitting or had quit. Intervention: N/A. Methods: Data collected in 6 focus group discussions were transcribed and analyzed in accord with principles of thematic qualitative methods. Results: We report the results across 4 interconnected themes: (1) the fight to quit takes several rounds, (2) the motivation of supportive competition, (3) challenges and benefits of connecting with smoke-free peers, and (4) playing up the physical and financial gains. Conclusions: Masculine-based perspectives positioned quitting alongside fighting for self-control, competing, connecting, physical prowess, and having extra cash as motivating components of programs to engage men in efforts to be smoke-free. It may be worthwhile to consider the inclusion of gain-framed and benefit-focused messaging in programs that support men’s tobacco cessation

Atomic and Molecular Opacities for Brown Dwarf and Giant Planet Atmospheres

We present a comprehensive description of the theory and practice of opacity calculations from the infrared to the ultraviolet needed to generate models of the atmospheres of brown dwarfs and extrasolar giant planets. Methods for using existing line lists and spectroscopic databases in disparate formats are presented and plots of the resulting absorptive opacities versus wavelength for the most important molecules and atoms at representative temperature/pressure points are provided. Electronic, ro-vibrational, bound-free, bound-bound, free-free, and collision-induced transitions and monochromatic opacities are derived, discussed, and analyzed. The species addressed include the alkali metals, iron, heavy metal oxides, metal hydrides, $H_2$, $H_2O$, $CH_4$, $CO$, $NH_3$, $H_2S$, $PH_3$, and representative grains. [Abridged]Comment: 28 pages of text, plus 22 figures, accepted to the Astrophysical Journal Supplement Series, replaced with more compact emulateapj versio

Simple iterative construction of the optimized effective potential for orbital functionals, including exact exchange

For exchange-correlation functionals that depend explicitly on the Kohn-Sham orbitals, the potential V_{\mathrm{xc}\sigma}(\re) must be obtained as the solution of the optimized effective potential (OEP) integral equation. This is very demanding and has limited the use of orbital functionals like exact exchange. We demonstrate that the OEP can be obtained iteratively by solving a system of partial differential equations instead of an integral equation. This amounts to calculating the orbital shifts that exactify the Krieger-Li-Iafrate (KLI) approximation. Unoccupied orbitals do not need to be calculated. Accuracy and efficiency of the method are shown for atoms and clusters using the exact exchange energy. Counter-intuitive asymptotic limits of the exact OEP, not accessible from previous constructions, are presented.Comment: Physical Review Letters, accepted for publication. 4 pages, 1 figur

Low Temperature Opacities

Previous computations of low temperature Rosseland and Planck mean opacities from Alexander & Ferguson (1994) are updated and expanded. The new computations include a more complete equation of state with more grain species and updated optical constants. Grains are now explicitly included in thermal equilibrium in the equation of state calculation, which allows for a much wider range of grain compositions to be accurately included than was previously the case. The inclusion of high temperature condensates such as Al$_2$O$_3$ and CaTiO$_3$ significantly affects the total opacity over a narrow range of temperatures before the appearance of the first silicate grains. The new opacity tables are tabulated for temperatures ranging from 30000 K to 500 K with gas densities from 10$^{-4}$ g cm$^{-3}$ to 10$^{-19}$ g cm$^{-3}$. Comparisons with previous Rosseland mean opacity calculations are discussed. At high temperatures, the agreement with OPAL and Opacity Project is quite good. Comparisons at lower temperatures are more divergent as a result of differences in molecular and grain physics included in different calculations. The computation of Planck mean opacities performed with the opacity sampling method are shown to require a very large number of opacity sampling wavelength points; previously published results obtained with fewer wavelength points are shown to be significantly in error. Methods for requesting or obtaining the new tables are provided.Comment: 39 pages with 12 figures. To be published in ApJ, April 200

Tetrahydrofurandiols (THF-diols), Leukotoxindiols (LTX-diols), and Endocrine Disruption in Rats

BACKGROUND: Ground corncob animal bedding and corn food products contain substances that disrupt endocrine function in rats. The disruptors were identified as isomeric mixtures of tetrahydrofurandiols (THF-diols; 9,12-oxy-10,13-dihydroxyoctadecanoic acid and 10,13-oxy-9,12-dihydroxyoctadecanoic acid) and leukotoxindiols (LTX-diols; 9,10-dihydroxy-12-octadecenoic acid and 12,13-dihydroxy-9-octadecenoic acid). The authentic compounds blocked sexual behavior in male rats and estrous cyclicity in female rats at oral doses of 2 ppm. OBJECTIVES: To define the lowest observed adverse effect level (LOAEL) for the THF-diols and LTX-diols in rats, we examined the nature of their interaction (additive or synergistic) and quantified the concentration of THF-diols in rat tissues. METHODS: Adult male and female rats were provided drinking solutions containing various doses of THF-diols and/or LTX-diols, and we evaluated their effects on male sexual behavior and female estrous cyclicity. Tissues were collected for THF-diol determination by gas chromatography–mass spectrometry. RESULTS: The LOAEL for THF-diols and LTX-diols for blocking estrous cyclicity was 0.5–1.0 ppm and 0.2–0.5 ppm, respectively. Higher concentrations (1–2 ppm) of THF-diols were required to block male sexual behavior. Combination studies with subthreshold doses of 0.05 ppm THF-diols plus 0.05 ppm LTX-diols revealed that their effects on estrous cyclicity were not synergistic. We were unable to detect THF-diols in tissues from rats treated with 10 ppm of the compounds, suggesting that metabolism may be involved. DISCUSSION: THF-diols, LTX-diols, and/or their metabolites likely act additively to disrupt endocrine function in male and female rats at concentrations (0.5–1 ppm) that are 200-fold lower than those of classical phytoestrogen endocrine disruptors

The HAT TRICK programme for improving physical activity, healthy eating and connectedness among overweight, inactive men: Study protocol of a pragmatic feasibility trial

Introduction  Physical activity, healthy eating and maintaining a healthy weight are associated with reduced risk of cardiovascular disease, type 2 diabetes and cancer and with improved mental health. Despite these benefits, many men do not meet recommended physical activity guidelines and have poor eating behaviours. Many health promotion programmes hold little appeal to men and consequently fail to influence men's health practices. HAT TRICK was designed as a 12-week face-to-face, gender-sensitised intervention for overweight and inactive men focusing on physical activity, healthy eating and social connectedness and was delivered in collaboration with a major junior Canadian ice hockey team (age range 16-20 years). The programme was implemented and evaluated to assess its feasibility. This article describes the intervention design and study protocol of HAT TRICK.  Methods and analysis  HAT TRICK participants (n=60) were men age 35 years, residing in the Okanagan Region of British Columbia, who accumulate 150 min of moderate to vigorous physical activity a week, with a body mass index of >25 kg/m 2 and a pant waist size of >38'. Each 90 min weekly session included targeted health education and theory-guided behavioural change techniques, as well as a progressive (ie, an increase in duration and intensity) group physical activity component. Outcome measures were collected at baseline, 12 weeks and 9 months and included the following: objectively measured anthropometrics, blood pressure, heart rate, physical activity and sedentary behaviour, as well as self-reported physical activity, sedentary behaviour, diet, smoking, alcohol consumption, sleep habits, risk of depression, health-related quality of life and social connectedness. Programme feasibility data (eg, recruitment, satisfaction, adherence, content delivery) were assessed at 12 weeks via interviews and self-report.  Ethics and dissemination  Ethical approval was obtained from the University of British Columbia Okanagan Behavioural Research Ethics Board (reference no H1600736). Study findings will be disseminated through academic meetings, peer-reviewed publication, web-based podcasts, social media, plain language summaries and co-delivered community presentations.  Trial registration number  ISRCTN43361357,Pre results

PCA-based lung motion model

Organ motion induced by respiration may cause clinically significant targeting errors and greatly degrade the effectiveness of conformal radiotherapy. It is therefore crucial to be able to model respiratory motion accurately. A recently proposed lung motion model based on principal component analysis (PCA) has been shown to be promising on a few patients. However, there is still a need to understand the underlying reason why it works. In this paper, we present a much deeper and detailed analysis of the PCA-based lung motion model. We provide the theoretical justification of the effectiveness of PCA in modeling lung motion. We also prove that under certain conditions, the PCA motion model is equivalent to 5D motion model, which is based on physiology and anatomy of the lung. The modeling power of PCA model was tested on clinical data and the average 3D error was found to be below 1 mm.Comment: 4 pages, 1 figure. submitted to International Conference on the use of Computers in Radiation Therapy 201