399 research outputs found
Heat transfer to a gas containing a cloud of particles Final report, 1 Jun. 1962 - 31 May 1968
Radiant heat transfer to particle cloud
Heat transfer to a gas containing a cloud of particles
Heat transfer to gas containing particle clou
Testing the viability of the interacting holographic dark energy model by using combined observational constraints
Using the data coming from the new 182 Gold type Ia supernova samples, the
shift parameter of the Cosmic Microwave Background given by the three-year
Wilkinson Microwave Anisotropy Probe observations, and the baryon acoustic
oscillation measurement from the Sloan Digital Sky Survey, and lookback
time measurements, we have performed a statistical joint analysis of the
interacting holographic dark energy model. Consistent parameter estimations
show us that the interacting holographic dark energy model is a viable
candidate to explain the observed acceleration of our universe.Comment: 15 pages, 9 figures, accepted for publication in JCA
Honokiol Induces Calpain-Mediated Glucose-Regulated Protein-94 Cleavage and Apoptosis in Human Gastric Cancer Cells and Reduces Tumor Growth
Background. Honokiol, a small molecular weight natural product, has been shown to possess potent anti-neoplastic and anti-angiogenic properties. Its molecular mechanisms and the ability of anti-gastric cancer remain unknown. It has been shown that the anti-apoptotic function of the glucose-regulated proteins (GRPs) predicts that their induction in neoplastic cells can lead to cancer progression and drug resistance. We explored the effects of honokiol on the regulation of GRPs and apoptosis in human gastric cancer cells and tumor growth. Methodology and Principal Findings. Treatment of various human gastric cancer cells with honokiol led to the induction of GRP94 cleavage, but did not affect GRP78. Silencing of GRP94 by small interfering RNA (siRNA) could induce cell apoptosis. Treatment of cells with honokiol or chemotherapeutics agent etoposide enhanced the increase in apoptosis and GRP94 degradation. The calpain activity and calpain-II (m-calpain) protein (but not calpain-I (mu-calpain)) level could also be increased by honokiol. Honokiol-induced GRP94 down-regulation and apoptosis in gastric cancer cells could be reversed by siRNA targeting calpain-II and calpain inhibitors. Furthermore, the results of immunofluorescence staining and immunoprecipitation revealed a specific interaction of GRP94 with calpain-II in cells following honokiol treatment. We next observed that tumor GRP94 over-expression and tumor growth in BALB/c nude mice, which were inoculated with human gastric cancer cells MKN45, are markedly decreased by honokiol treatment. Conclusions and Significance. These results provide the first evidence that honokiol-induced calpain-II-mediated GRP94 cleavage causes human gastric cancer cell apoptosis. We further suggest that honokiol may be a possible therapeutic agent to improve clinical outcome of gastric cancer
Genome sequence of an Australian kangaroo, Macropus eugenii, provides insight into the evolution of mammalian reproduction and development.
BACKGROUND: We present the genome sequence of the tammar wallaby, Macropus eugenii, which is a member of the kangaroo family and the first representative of the iconic hopping mammals that symbolize Australia to be sequenced. The tammar has many unusual biological characteristics, including the longest period of embryonic diapause of any mammal, extremely synchronized seasonal breeding and prolonged and sophisticated lactation within a well-defined pouch. Like other marsupials, it gives birth to highly altricial young, and has a small number of very large chromosomes, making it a valuable model for genomics, reproduction and development. RESULTS: The genome has been sequenced to 2 Ă— coverage using Sanger sequencing, enhanced with additional next generation sequencing and the integration of extensive physical and linkage maps to build the genome assembly. We also sequenced the tammar transcriptome across many tissues and developmental time points. Our analyses of these data shed light on mammalian reproduction, development and genome evolution: there is innovation in reproductive and lactational genes, rapid evolution of germ cell genes, and incomplete, locus-specific X inactivation. We also observe novel retrotransposons and a highly rearranged major histocompatibility complex, with many class I genes located outside the complex. Novel microRNAs in the tammar HOX clusters uncover new potential mammalian HOX regulatory elements. CONCLUSIONS: Analyses of these resources enhance our understanding of marsupial gene evolution, identify marsupial-specific conserved non-coding elements and critical genes across a range of biological systems, including reproduction, development and immunity, and provide new insight into marsupial and mammalian biology and genome evolution
The Precarity of Progress: Implications of a Shifting Gendered Division of Labor for Relationships and Well-Being as a Function of Country-Level Gender Equality
The onset of the COVID-19 pandemic saw a shift toward a more traditional division of labor–one where women took greater
responsibility for household tasks and childcare than men. We tested whether this regressive shift was more acutely perceived
and experienced by women in countries with greater gender equality. Cross-cultural longitudinal survey data for women and
men (N = 10,238) was collected weekly during the first few months of the pandemic. Multilevel modelling analyses, based
on seven waves of data collection, indicated that a regressive shift was broadly perceived but not uniformly felt. Women and
men alike perceived a shift toward a more traditional division of household labor during the first few weeks of the pandemic.
However, this perception only undermined women’s satisfaction with their personal relationships and subjective mental health
if they lived in countries with higher levels of economic gender equality. Among women in countries with lower levels of
economic gender equality, the perceived shift predicted higher relationship satisfaction and mental health. There were no
such effects among men. Taken together, our results suggest that subjective perceptions of disempowerment, and the gender
role norms that underpin them, should be considered when examining the gendered impact of global crisis
Growth of Large-Area and Highly Crystalline MoS2 Thin Layers on Insulating Substrates
The two-dimensional layer of molybdenum disulfide (MoS2) has recently
attracted much interest due to its direct-gap property and potential
applications in optoelectronics and energy harvesting. However, the synthetic
approach to obtain high quality and large-area MoS2 atomic thin layers is still
rare. Here we report that the high temperature annealing of a thermally
decomposed ammonium thiomolybdate layer in the presence of sulfur can produce
large-area MoS2 thin layers with superior electrical performance on insulating
substrates. Spectroscopic and microscopic results reveal that the synthesized
MoS2 sheets are highly crystalline. The electron mobility of the bottom-gate
transistor devices made of the synthesized MoS2 layer is comparable with those
of the micromechanically exfoliated thin sheets from MoS2 crystals. This
synthetic approach is simple, scalable and applicable to other transition metal
dichalcogenides. Meanwhile, the obtained MoS2 films are transferable to
arbitrary substrates, providing great opportunities to make layered composites
by stacking various atomically thin layers.Comment: manuscript submitted on 11-Dec-2011, revision submitted on
16-Feb-201
Combined Simulation and Experimental Study of Large Deformation of Red Blood Cells in Microfluidic Systems
Author manuscript; available in PMC 2012 March 1.We investigate the biophysical characteristics of healthy human red blood cells (RBCs) traversing microfluidic channels with cross-sectional areas as small as 2.7 × 3 μm. We combine single RBC optical tweezers and flow experiments with corresponding simulations based on dissipative particle dynamics (DPD), and upon validation of the DPD model, predictive simulations and companion experiments are performed in order to quantify cell deformation and pressure–velocity relationships for different channel sizes and physiologically relevant temperatures. We discuss conditions associated with the shape transitions of RBCs along with the relative effects of membrane and cytosol viscosity, plasma environments, and geometry on flow through microfluidic systems at physiological temperatures. In particular, we identify a cross-sectional area threshold below which the RBC membrane properties begin to dominate its flow behavior at room temperature; at physiological temperatures this effect is less profound.Singapore-MIT Alliance for Research and TechnologyUnited States. National Institutes of Health (National Heart, Lung, and Blood Institute Award R01HL094270
Pandemic Boredom: Little Evidence That Lockdown-Related Boredom Affects Risky Public Health Behaviors Across 116 Countries
Some public officials have expressed concern that policies mandating collective public health behaviors (e.g., national/regional "lockdown ") may result in behavioral fatigue that ultimately renders such policies ineffective. Boredom, specifically, has been singled out as one potential risk factor for noncompliance. We examined whether there was empirical evidence to support this concern during the COVID-19 pandemic in a large cross-national sample of 63,336 community respondents from 116 countries. Although boredom was higher in countries with more COVID-19 cases and in countries that instituted more stringent lockdowns, such boredom did not predict longitudinal within-person decreases in social distancing behavior (or vice versa; n = 8,031) in early spring and summer of 2020. Overall, we found little evidence that changes in boredom predict individual public health behaviors (handwashing, staying home, self-quarantining, and avoiding crowds) over time, or that such behaviors had any reliable longitudinal effects on boredom itself. In summary, contrary to concerns, we found little evidence that boredom posed a public health risk during lockdown and quarantine
Diacylglycerol Kinase β Knockout Mice Exhibit Lithium-Sensitive Behavioral Abnormalities
BACKGROUND: Diacylglycerol kinase (DGK) is an enzyme that phosphorylates diacylglycerol (DG) to produce phosphatidic acid (PA). DGKβ is widely distributed in the central nervous system, such as the olfactory bulb, cerebral cortex, striatum, and hippocampus. Recent studies reported that the splice variant at the COOH-terminal of DGKβ was related to bipolar disorder, but its detailed mechanism is still unknown. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we performed behavioral tests using DGKβ knockout (KO) mice to investigate the effects of DGKβ deficits on psychomotor behavior. DGKβ KO mice exhibited some behavioral abnormalities, such as hyperactivity, reduced anxiety, and reduced depression. Additionally, hyperactivity and reduced anxiety were attenuated by the administration of the mood stabilizer, lithium, but not haloperidol, diazepam, or imipramine. Moreover, DGKβ KO mice showed impairment in Akt-glycogen synthesis kinase (GSK) 3β signaling and cortical spine formation. CONCLUSIONS/SIGNIFICANCE: These findings suggest that DGKβ KO mice exhibit lithium-sensitive behavioral abnormalities that are, at least in part, due to the impairment of Akt-GSK3β signaling and cortical spine formation
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