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Results for “Solubility”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

DFT studies of the electron density distribution and donor-acceptor interactions in water-soluble aminohydroximate metallamacrocyclic Ca{sup II} and Y{sup III} complexes

The topology of the electron density and the nature of donor-acceptor interactions in copper-based glycinehydroximate metallamacrocycles bearing calcium(II) and yttrium(III) have been studied for the first time in terms of the density functional theory (DFT). The DFT calculations at the M06/Def2-TZVP level were performed taking into account non-specific (PCM) and specific solvation. Quantitative estimations of the donor-acceptor interactions and topological properties of the electron density were obtained. According to them, the thermodynamic stability of the yttrium complex is higher than that of the calcium analog. The calculated values of the Gibbs energy changes indicate the spontaneous substitution of Ca{sup 2+} by Y{sup 3+} in the metallamacrocycle in an aqueous medium.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

The Thermoelectric Properties and Solubility Limit of CuFeS 2(1-x) Se 2x

CuFeS 2 is an earth-abundant material with a potential for use in thermoelectric power generation. It is an n-type semiconductor with a small band gap, a large thermopower, and a low electrical resistivity. Previous studies have focused on the electrical properties and doping the material, to some success. In this study, we investigate the effects of selenium substitution on the sulfur site in an attempt to lower thermal conductivity while maintaining good electrical properties. Here, our results shows that selenium substitution is an effective method of improving zT through a large increase in power factor, and works well for reducing thermal conductivity at room temperature, but is not as effective in this regard at higher temperatures.

chalcopyrite↗
DOE OSTI2014

Quantization of soluble classical constrained systems

The derivation of the brackets among coordinates and momenta for classical constrained systems is a necessary step toward their quantization. Here we present a new approach for the determination of the classical brackets which does neither require Dirac’s formalism nor the symplectic method of Faddeev and Jackiw. This approach is based on the computation of the brackets between the constants of integration of the exact solutions of the equations of motion. From them all brackets of the dynamical variables of the system can be deduced in a straightforward way.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Soluble FLT-1 rules placental destiny

Highlights: • Placenta previa is an obstetric complication which can cause massive hemorrhage. • Some pregnant women recover from placenta previa due to a phenomenon called “migration” of the placenta. • The sFLT-1 expression level is locally high in the caudal part of the human placenta in patients with placenta previa. • In mice, sFlt-1 expression level was significantly increased by ablation of uterine arteries. • Our study suggests that “migration” of the placenta is derived from placental degeneration and sFlt-1 plays an important role in placental degeneration. Placenta previa is an abnormality in which the placenta covers the internal uterine os, and it can cause serious morbidity and mortality in both mother and fetus due to catastrophic hemorrhage. Some pregnant women recover from placenta previa due to a phenomenon called “migration.” However, the mechanism of “migration” of the placenta has not been elucidated.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Sesaminol diglucoside, a water-soluble lignan from sesame seeds induces brown fat thermogenesis in mice

Highlights: • Aqueous extract of black sesame seeds induces brown fat thermogenesis in mice. • SDG purified from the aqueous sesame extract prevents weight gain in HFD fed mice. • SDG induces brown fat thermogenesis through β3-adrenergic receptors. Brown adipose tissue (BAT) is the site of non-shivering thermogenesis in mammals, wherein energy is dissipated as heat. We observed that aqueous extract of black sesame seed triggers an increase in the expression of Uncoupling Protein 1 (UCP1) in brown adipocytes from mice. The active component from the extract was purified and identified to be sesaminol diglucoside (SDG). SDG treatment decreased mass of white fat pads and serum glucose levels and increased UCP1 levels in BAT thereby protecting mice against high fat induced weight gain. Further in silico and in vitro studies revealed that these effects are due to the agonist like behaviour of SDG towards beta 3 adrenergic receptors (β3-AR). Together, our results suggest that SDG induces BAT mediated thermogenesis through β3-AR and protects mice against diet-induced obesity.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

Water-soluble drug partitioning and adsorption in HEMA/MAA hydrogels

Two-photon confocal microscopy and back extraction with UV/Vis-absorption spectrophotometry quantify equilibrium partition coefficients, k, for six prototypical drugs in five soft-contact-lens-material hydrogels over a range of water contents from 40 to 92%. Partition coefficients were obtained for acetazolamide, caffeine, hydrocortisone, Oregon Green 488, sodium fluorescein, and theophylline in 2-hydroxyethyl methacrylate/methacrylic acid (HEMA/MAA, pK a ≈ 5.2) copolymer hydrogels as functions of composition, aqueous pH (2 and 7.4), and salinity. At pH 2, the hydrogels are nonionic, whereas at pH 7.4, hydrogels are anionic due to MAA ionization. Solute adsorption on and nonspecific electrostatic interaction with the polymer matrix are pronounced. To express deviation from ideal partitioning, we define an enhancement or exclusion factor, E≡k/φ 1 , where φ 1 is hydrogel water volume fraction. All solutes exhibit E>1 in 100wt % HEMA hydrogels owing to strong specific adsorption to HEMA strands. For all solutes, E significantly decreases upon incorporation of anionic MAA into the hydrogel due to lack of adsorption onto charged MAA moieties. For dianionic sodium fluorescein and Oregon Green 488, and partially ionized monoanionic acetazolamide at pH 7.4, however, the decrease in E is more severe than that for similar-sized nonionic solutes. Conversely, at pH 2, E generally increases with addition of the nonionic MAA copolymer due to strong preferential adsorption to the uncharged carboxylic-acid group of MAA. For all cases, we quantitatively predict enhancement factors for the six drugs using only independently obtained parameters. In dilute solution for solute i , E i is conveniently expressed as a product of individual enhancement factors for size exclusion (E$_i^{ex}$), electrostatic interaction (E$_i^{el}$), and specific adsorption (E$_i^{ad}$):E$_i$≡E$_i^{ex}$E$_i^{el}$E$_i^{ad}$. Finally, to obtain the individual enhancement factors, we employ an extended Ogston mesh-size distribution for Eiex; Donnan equilibrium for E$_i^{el}$; and Henry's law characterizing specific adsorption to the polymer chains for E$_i^{ad}$. Predicted enhancement factors are in excellent agreement with experiment.

back extraction↗