22 research outputs found
Controlled Ecological Life Support Systems (CELSS) physiochemical waste management systems evaluation
Parametric data for six waste management subsystems considered for use on the Space Station are compared, i.e.: (1) dry incineration; (2) wet oxidation; (3) supercritical water oxidation; (4) vapor compression distillation; (5) thermoelectric integrated membrane evaporation system; and (6) vapor phase catalytic ammonia removal. The parameters selected for comparison are on-orbit weight and volume, resupply and return to Earth logistics, power consumption, and heat rejection. Trades studies are performed on subsystem parameters derived from the most recent literature. The Boeing Engineering Trade Study (BETS), an environmental control and life support system (ECLSS) trade study computer program developed by Boeing Aerospace Company, is used to properly size the subsystems under study. The six waste treatment subsystems modeled in this program are sized to process the wastes for a 90-day Space Station mission with an 8-person crew, and an emergency supply period of 28 days. The resulting subsystem parameters are compared not only on an individual subsystem level but also as part of an integrated ECLSS
Structural and chiroptical analysis of naturally occurring (-)-strychnine.
Structural aspects such as chemical exchange, dimerization, solvent association, nitrogen inversion and protonation status of strychnine were investigated using experimental and calculated data. The information was mainly interpreted in view of a successful determination of the absolute configuration (AC) with strychnine (base and salt) as test molecule due to its importance in chemistry. By geometry optimization a stable isomer of protonated strychnine was found with an inverted nitrogen, however, 25 kcal/mol higher in energy. It is shown that solvent association can be assumed in protic solvents such as methanol and dimerization to a small extent in polar/protic solvents. However, the monomeric structural model neglecting explicit solvent molecules still allows the correct prediction of the AC of base and hydrochloride using optical rotation and ECD data
Aminothiazole-featured pirinixic acid derivatives as dual 5-lipoxygenase and microsomal prostaglandin E2 synthase-1 inhibitors with improved potency and efficiency in vivo.
The 5-lipoxygenase inhibitor RF-22c potently suppresses leukotriene biosynthesis in cellulo and blocks bronchoconstriction and inflammation in vivo
5-Lipoxygenase (5-LO) catalyzes the first two steps in leukotriene (LT) biosynthesis. Because LTs play pivotal roles in allergy and inflammation, 5-LO represents a valuable target for anti-inflammatory drugs. Here, we investigated the molecular mechanism, the pharmacological profile, and the in vivo effectiveness of the novel 1,2-benzoquinone-featured 5-LO inhibitor RF-22c. Compound RF-22c potently inhibited 5-LO product synthesis in neutrophils and monocytes (IC50 ≥ 22 nM) and in cell-free assays (IC50 ≥ 140 nM) without affecting 12/15-LOs, cyclooxygenase (COX)-1/2, or arachidonic acid release, in a specific and reversible manner, supported by molecular docking data. Antioxidant or iron-chelating properties were not evident for RF-22c and 5-LO-regulatory cofactors like Ca2+ mobilization, ERK-1/2 activation, and 5-LO nuclear membrane translocation and interaction with 5-LO-activating protein (FLAP) were unaffected. RF-22c (0.1 mg/kg; i.p.) impaired (I) bronchoconstriction in ovalbumin-sensitized mice challenged with acetylcholine, (II) exudate formation in carrageenan-induced paw edema, and (III) zymosan-induced leukocyte infiltration in air pouches. Taken together, RF-22c is a highly selective and potent 5-LO inhibitor in intact human leukocytes with pronounced effectiveness in different models of inflammation that warrants further preclinical analysis of this agent as anti-inflammatory drug
Insight into the Electrochemical and Semiconducting Properties of Native Oxide Films on Ti Metal and Its Ti–6Al–4V Alloy in Borate Buffer Solutions
Endogenous testosterone and cortisol modulate neural responses during induced anger control
Research with violent offenders and delinquent adolescents suggests that endogenous testosterone concentrations have the strongest positive correlations with violence among men who have low concentrations of cortisol. The present study tested the hypothesis that testosterone and cortisol would similarly interact to determine neural activation in regions supporting self-regulation in response to anger provocation. Nineteen healthy Asian male participants were insulted and asked to control their anger during functional magnetic resonance imaging (fMRI). When cortisol levels were low, testosterone positively correlated with activation in the dorsolateral prefrontal cortex (dlPFC) and thalamus, but not when cortisol levels were high. During induced anger control, functional connectivity was increased between the amygdala and a top-down prefrontal cortical control network. Moreover, the amygdala-PFC connectivity was strongest among those high in testosterone and low in cortisol. This research highlights a possible neural mechanism by which testosterone and cortisol may influence anger control