Program to determine space vehicle response to wind turbulence

Computer program was developed as prelaunch wind monitoring tool for Saturn 5 vehicle. Program accounts for characteristic wind changes including turbulence power spectral density, wind shear, peak wind velocity, altitude, and wind direction using stored variational statistics

An estimate of the global distribution of radon emissions from the ocean

Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 31 (2004): L19104, doi:10.1029/2004GL021051.There is a need for improved estimates of the radon (222Rn) flux density from the ocean for use in the modeling and interpretation of atmospheric radon in global climate and air pollution studies. We use a modification of a frequently used model of gas transfer to generate global predictions of ocean radon flux density for each month of the year (climate averaged) on a 192 by 94 global grid. Compared with the often-used approximation of a constant radon flux from the ocean, the model's predictions indicate large variations over regions of the ocean (a factor of ten is not uncommon). For example, latitude bands near the equator and Southern Ocean are predicted to emit relatively high average radon flux compared with other latitude bands. The predicted annually-averaged flux density from the ocean is 0.0382 mBq m−2 s−1 (0.00182 atoms cm−2 s−1), smaller than some commonly-used estimates

Intrauterine growth restriction increases fetal hepatic gluconeogenic capacity and reduces messenger ribonucleic acid translation initiation and nutrient sensing in fetal liver and skeletal muscle.

Expression of key metabolic genes and proteins involved in mRNA translation, energy sensing, and glucose metabolism in liver and skeletal muscle were investigated in a late-gestation fetal sheep model of placental insufficiency intrauterine growth restriction (PI-IUGR). PI-IUGR fetuses weighed 55% less; had reduced oxygen, glucose, isoleucine, insulin, and IGF-I levels; and had 40% reduction in net branched chain amino acid uptake. In PI-IUGR skeletal muscle, levels of insulin receptor were increased 80%, whereas phosphoinositide-3 kinase (p85) and protein kinase B (AKT2) were reduced by 40%. Expression of eukaryotic initiation factor-4e was reduced 45% in liver, suggesting a unique mechanism limiting translation initiation in PI-IUGR liver. There was either no change (AMP activated kinase, mammalian target of rapamycin) or a paradoxical decrease (protein phosphatase 2A, eukaryotic initiation factor-2 alpha) in activation of major energy and cell stress sensors in PI-IUGR liver and skeletal muscle. A 13- to 20-fold increase in phosphoenolpyruvate carboxykinase and glucose 6 phosphatase mRNA expression in the PI-IUGR liver was-associated with a 3-fold increase in peroxisome proliferator-activated receptor-gamma coactivator-1 alpha mRNA and increased phosphorylation of cAMP response element binding protein. Thus PI-IUGR is-associated with reduced branched chain amino acid uptake and growth factors, yet up-regulation of proximal insulin signaling and a marked increase in the gluconeogenic pathway. Lack of activation of several energy and stress sensors in fetal liver and skeletal muscle, despite hypoxia and low energy status, suggests a novel strategy for survival in the PI-IUGR fetus but with potential maladaptive consequences for reduced nutrient sensing and insulin sensitivity in postnatal life

HySafe Standard benchmark Problem SBEP-V11: Predictions of hydrogen release and dispersion from a CGH2 bus in an underpass

One of the tasks of the HySafe Network of Excellence was the evaluation of available CFD tools and models for dispersion and combustion in selected hydrogen release scenarios identified as “standard benchmark problems” (SBEPs). This paper presents the results of the HySafe standard benchmark problem SBEP-V11. The situation considered is a high pressure hydrogen jet release from a compressed gaseous hydrogen (CGH2) bus in an underpass. The bus considered is equipped with 8 cylinders of 5 kg hydrogen each at 35 MPa storage pressure. The underpass is assumed to be of the common beam and slab type construction with I-beams spanning across the highway at 3 m centres (normal to the bus), plus cross bracing between the main beams, and light armatures parallel to the bus direction. The main goal of the present work was to evaluate the role of obstructions on the underside of the bridge deck on the dispersion patterns and assess the potential for hydrogen accumulation. Four HySafe partners participated in this benchmark, with 4 different CFD codes, ADREA-HF, CFX, FLACS and FLUENT. Four scenarios were examined in total. In the base case scenario 20 kg of hydrogen was released in the basic geometry. In Sensitivity Test 1 the release position was moved so that the hydrogen jet could hit directly the light armature on the roof of the underpass. In Sensitivity Test 2 the underside of the bridge deck was flat. In Sensitivity Test 3 the release was from one cylinder instead of four (5 kg instead of 20). The paper compares the results predicted by the four different computational approaches and attempts to identify the reasons for observed disagreements. The paper also concludes on the effects of the obstructions on the underside of the bridge deck

Impact of oxetane incorporation on the structure and stability of alpha-helical peptides

Peptide-based drugs combine advantages of larger biological therapeutics with those of small molecule drugs, but they generally display poor permeability and metabolic stability. Recently, we introduced a new type of peptide bond isostere, in which the backbone carbonyl is replaced with a 3-amino oxetane heterocycle, into short linear peptides with the aim of improving their therapeutic potential. In this study, we have explored the impact of oxetane modification on α-helical peptides to establish whether or not this modification is tolerated in this biologically important structural motif. The oxetane modification was introduced at two positions in a well-characterised helical peptide sequence, and circular dichroism and NMR spectroscopy were used to measure the resulting secondary structure content under different experimental conditions. Our data demonstrated that introduction of an oxetane into the peptide backbone results in a significant loss of helicity, regardless of where in the sequence the modification is placed. The molecular determinants of this destabilisation were then explored using steered molecular dynamics simulations, a computational method analogous to single molecule spectroscopy. Our simulations indicated that oxetane modification introduces a kink in the helical axis, alters the dihedral angles of residues up to three positions away from the modification, and disrupts the (i, i + 4) hydrogen bonding pattern characteristic of α-helices in favour of new, short-range hydrogen bonds. The detailed structural understanding provided in this work can direct future design of chemically modified peptides

Prenatal Exposure to Tobacco and Offspring Neurocognitive Development in the Healthy Start Study

Objective: To explore the associations between prenatal exposure to tobacco and neurocognitive development, in the absence of prematurity or low birth weight. Study design: We followed mother-child pairs within Healthy Start through 6 years of age. Children were born at ≥37 weeks of gestation with a birth weight of ≥2500 g. Parents completed the Third Edition Ages and Stages Questionnaire (n = 246) and children completed a subset of the National Institutes of Health Toolbox Cognition Battery (n = 200). The Ages and Stages Questionnaire domains were dichotomized as fail/monitor and pass. Maternal urinary cotinine was measured at approximately 27 weeks of gestation. Separate logistic regression models estimated associations between prenatal exposure to tobacco (cotinine below vs above the limit of detection) and the Ages and Stages Questionnaire domains. Separate linear regression models estimated associations between prenatal exposure to tobacco and fully corrected T-scores for inhibitory control, cognitive flexibility, and receptive language, as assessed by the National Institutes of Health Toolbox. A priori covariates included sex, maternal age, maternal education, daily caloric intake during pregnancy, race/ethnicity, household income, maternal psychiatric disorders, and, in secondary models, postnatal exposure to tobacco. Results: Compared with unexposed offspring, exposed offspring were more likely to receive a fail/monitor score for fine motor skills (OR, 3.9; 95% CI, 1.5-10.3) and decreased inhibitory control (B: −3.0; 95% CI, −6.1 to −0.7). After adjusting for postnatal exposure, only the association with fine motor skills persisted. Conclusions: Prenatal and postnatal exposures to tobacco may influence neurocognitive development, in the absence of preterm delivery or low birth weight. Increased developmental screening may be warranted for exposed children