575 research outputs found
High temperature properties of sodium, potassium, and cesium thirteenth progress report
Thermophysical properties of sodium, potassium, and cesium at high temperatures - density of liquid potassium and vapor pressure of cesiu
Ambiguous Loss Feelings Amongst Caregivers of Operation Enduring Freedom Veterans
This quantitative study compares the possible relationship between ambiguous loss and the stress level of caregivers of Operation Enduring Freedom (OEF) veterans who served in combat. Injured servicemembers need caregivers to assist them in caring for their physical and mental health needs. This study examined whether there is a relationship between the perceived ambiguous loss among caregivers of OEF injured veterans and the stress level experienced by caregivers. The theoretical framework for this study is the ambiguous loss theory. The methodology used to test the hypothesis is a quantitative correlational design to compare ambiguous loss variables amongst caregivers of injured OEF veterans. The independent variable is the ambiguous loss of sense of physical presence but the psychological absence. The dependent variable is stress. The control variable is the perceived stress level of caregivers of OEF-injured veterans. The hypothesis was tested using the linear regression test. Stress is increased due to caregivers’ perception of ambiguous loss resulting from the injured veterans’ continued physical presence, but the psychological absence was substantiated. The Pearson Correlation test displayed a correlation between ambiguous loss and stress. This study contributes to understanding caregivers, military/veteran caregivers, and veterans’ stress and coping. Positive social change can be affected through resiliency skill-based resources for caregivers
A Study of Space Station Contamination Effects
A workshop was held with the specific objective of reviewing the state-of-knowledge regarding Space Station contamination, the extent to which the various categories of contamination can be predicted, and the extent to which the predicted levels would interfere with onboard scientific investigations or space station functions. The papers presented at the workshop are compiled and address the following topics: natural environment, plasma electromagnetic environment, optical environment, particulate environment, spacecraft contamination, surface physics processes, laboratory experiments and vented chemicals/contaminants
High-temperature properties of cesium
High temperature properties of cesium - density and vapor pressure of liquid cesium, and saturation and superheat properties of cesium vapo
Cell-specific discrimination of desmosterol and desmosterol mimetics confers selective regulation of LXR and SREBP in macrophages.
Activation of liver X receptors (LXRs) with synthetic agonists promotes reverse cholesterol transport and protects against atherosclerosis in mouse models. Most synthetic LXR agonists also cause marked hypertriglyceridemia by inducing the expression of sterol regulatory element-binding protein (SREBP)1c and downstream genes that drive fatty acid biosynthesis. Recent studies demonstrated that desmosterol, an intermediate in the cholesterol biosynthetic pathway that suppresses SREBP processing by binding to SCAP, also binds and activates LXRs and is the most abundant LXR ligand in macrophage foam cells. Here we explore the potential of increasing endogenous desmosterol production or mimicking its activity as a means of inducing LXR activity while simultaneously suppressing SREBP1c-induced hypertriglyceridemia. Unexpectedly, while desmosterol strongly activated LXR target genes and suppressed SREBP pathways in mouse and human macrophages, it had almost no activity in mouse or human hepatocytes in vitro. We further demonstrate that sterol-based selective modulators of LXRs have biochemical and transcriptional properties predicted of desmosterol mimetics and selectively regulate LXR function in macrophages in vitro and in vivo. These studies thereby reveal cell-specific discrimination of endogenous and synthetic regulators of LXRs and SREBPs, providing a molecular basis for dissociation of LXR functions in macrophages from those in the liver that lead to hypertriglyceridemia
Pay What You Want as a Marketing Strategy in Monopolistic and Competitive Markets
Pay What You Want (PWYW) can be an attractive marketing strategy to price discriminate between fair-minded and selfish customers, to fully penetrate a market without giving away the product for free, and to undercut competitors that use posted prices. We report on laboratory experiments that identify causal factors determining the willingness of buyers to pay voluntarily under PWYW. Furthermore, to see how competition affects the viability of PWYW, we implement markets in which a PWYW seller competes with a traditional seller. Finally, we endogenize the market structure and let sellers choose their pricing strategy. The experimental results show that outcome-based social preferences and strategic considerations to keep the seller in the market can explain why and how much buyers pay voluntarily to a PWYW seller. We find that PWYW can be viable in isolation, but it is less successful as a competitive strategy because it does not drive traditional posted-price sellers out of the market. Instead, the existence of a posted-price competitor reduces buyers’ payments and prevents the PWYW seller from fully penetrating the market. If given the choice, the majority of sellers opt for setting a posted price rather than a PWYW pricing. We discuss the implications of these results for the use of PWYW as a marketing strategy
Semiconductor thermal and electrical properties decoupled by localized phonon resonances
Thermoelectric materials convert heat into electricity through thermally
driven charge transport in solids, or vice versa for cooling. To be competitive
with conventional energy-generation technologies, a thermoelectric material
must possess the properties of both an electrical conductor and a thermal
insulator. However, these properties are normally mutually exclusive because of
the interconnection of the scattering mechanisms for charge carriers and
phonons. Recent theoretical investigations on sub-device scales have revealed
that silicon membranes covered by nanopillars exhibit a multitude of local
phonon resonances, spanning the full spectrum, that couple with the
heat-carrying phonons in the membrane and collectively cause a reduction in the
in-plane thermal conductivitywhile, in principle, not affecting the
electrical properties because the nanopillars are external to the pathway of
voltage generation and charge transport. Here this effect is demonstrated
experimentally for the first time by investigating device-scale suspended
silicon membranes with GaN nanopillars grown on the surface. The nanopillars
cause up to 21 % reduction in the thermal conductivity while the electrical
conductivity and the Seebeck coefficient remain unaffected, thus demonstrating
an unprecedented decoupling in the semiconductor's thermoelectric properties.
The measured thermal conductivity behavior for coalesced nanopillars and
corresponding lattice-dynamics calculations provide further evidence that the
reductions are mechanistically tied to the phonon resonances. This finding
breaks a longstanding trade-off between competing properties in
thermoelectricity and paves the way for engineered high-efficiency solid-state
energy recovery and cooling
Tissue damage drives co-localization of NF-kappa B, Smad3, and Nrf2 to direct Rev-erb sensitive wound repair in mouse macrophages
Although macrophages can be polarized to distinct phenotypes in vitro with individual ligands, in vivo they encounter multiple signals that control their varied functions in homeostasis, immunity, and disease. Here, we identify roles of Rev-erb nuclear receptors in regulating responses of mouse macrophages to complex tissue damage signals and wound repair. Rather than reinforcing a specific program of macrophage polarization, Rev-erbs repress subsets of genes that are activated by TLR ligands, IL4, TGF beta, and damage-associated molecular patterns (DAMPS). Unexpectedly, a complex damage signal promotes co-localization of NF-kappa B, Smad3, and Nrf2 at Rev-erb-sensitive enhancers and drives expression of genes characteristic of multiple polarization states in the same cells. Rev-erb-sensitive enhancers thereby integrate multiple damage-activated signaling pathways to promote a wound repair phenotype
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