1,203 research outputs found
A High-Order Unifying Discontinuous Formulation for the Navier-Stokes Equations on 3D Mixed Grids
This is the published version. Copyright 2011 © EDP SciencesThe newly developed unifying discontinuous formulation named the correction procedure via reconstruction (CPR) for conservation laws is extended to solve the Navier-Stokes equations for 3D mixed grids. In the current development, tetrahedrons and triangular prisms are considered. The CPR method can unify several popular high order methods including the discontinuous Galerkin and the spectral volume methods into a more efficient differential form. By selecting the solution points to coincide with the flux points, solution reconstruction can be completely avoided. Accuracy studies confirmed that the optimal order of accuracy can be achieved with the method. Several benchmark test cases are computed by solving the Euler and compressible Navier-Stokes equations to demonstrate its performance
A Modified KNN Algorithm for Activity Recognition in Smart Home
Nowadays, more and more elderly people cannot take care of themselves, and feel uncomfortable in daily activities. Smart home systems can help to improve daily life of elderly people. A smart home can bring residents a more comfortable living environment by recognizing the daily activities automatically. In this paper, in order to improve the accuracy of activity recognition in smart homes, we conduct some improvements in data preprocess and recognition phase, and more importantly, a novel sensor segmentation method and a modified KNN algorithm are proposed. The segmentation algorithm employs segment sensor data into fragments based on predefined activity knowledge, and then the proposed modified KNN algorithm uses center distances as a measure for classification. We also conduct comprehensive experiments, and the results demonstrate that the proposed method outperforms the other classifiers
SMA observations of C2H in High-Mass Star Forming Regions
CH is a representative hydrocarbon that is abundant and ubiquitous in the
interstellar medium (ISM). To study its chemical properties, we present
Submillimeter Array (SMA) observations of the CH and HCN
transitions and the 1.1 mm continuum emission toward four OB
cluster-forming regions, AFGL 490, ON 1, W33 Main, and G10.6-0.4, which cover a
bolometric luminosity range of 10--10 . We found that
on large scales, the CH emission traces the dense molecular envelope.
However, for all observed sources, the peaks of CH emission are offset by
several times times 10 AU from the peaks of 1.1 mm continuum emission,
where the most luminous stars are located. By comparing the distribution and
profiles of CH hyperfine lines and the 1.1 mm continuum emission, we find
that the CH column density (and abundance) around the 1.1 mm continuum
peaks is lower than those in the ambient gas envelope. Chemical models suggest
that CH might be transformed to other species owing to increased
temperature and density; thus, its reduced abundance could be the signpost of
the heated molecular gas in the 10 AU vicinity around the embedded
high-mass stars. Our results support such theoretical prediction for centrally
embedded -- OB star-forming cores, while future
higher-resolution observations are required to examine the CH
transformation around the localized sites of high-mass star formation.Comment: 10 pages, 6 figures. ApJ accepted. Comments welcom
Role of adiponectin/phosphatidylinositol 3-kinase/protein kinase B signaling pathway on limb ischemic preconditioning on myocardial protection
The adiponectin/phosphatidylinositol 3-kinase/protein kinase B (ADP/PI3k/Akt) signal transduction pathway has an important role in promoting cell survival. This study was designed to determine if the ADP/PI3K/Akt signaling pathway has a role in the mechanism of ischemia–reperfusion injury in vivo. Sprague–Dawley rats were divided into five groups of six: Group A was the sham group, group B was the myocardial ischemia–reperfusion injury (MIRI) group; the left anterior descending coronary artery (LAD) was ligated and, after 30 min of ischemia, reperfusion was conducted for 120 min, group C was the limb ischemia preconditioning (LIPC) group; the femoral artery was blocked continuously for 5 min, and sustainable reperfusion was carried out for 5 min, and this procedure was repeated thrice. The MIRI experiment was carried out on the fourth day after consecutive preconditioning for 3 days. The surgical procedure was the same as with the MIRI model. Group D was the LY294002 pretreatment group: 15 min before reperfusion, ischemic rats underwent pretreatment with LY294002. The final group was the LIPC+LY294002 group; after limb ischemia preconditioning, rats underwent LY294002 pretreatment 15 min before reperfusion. Expression of ADP and adiponectin receptor 1 (ADPR1) messenger ribonucleic acid (mRNA), PI3k and p-Akt protein increased significantly in the myocardial tissue of the LIPC group in comparison with that in the sham group. This finding suggests that limb ischemic preconditioning increased the expression of ADP in the myocardial tissue of rats with myocardial ischemia–reperfusion injury. It also demonstrated that ADP activated PI3k by the ADP/PI3k/Akt signaling pathway to increase the phosphorylation of the effector protein Akt.Key words: Limb ischemic preconditioning, ischemia–reperfusion injury, phosphatidylinositol 3-kinase (PI3k), protein kinase (p-Akt), signal transduction
Tramadol Pretreatment Enhances Ketamine-Induced Antidepressant Effects and Increases Mammalian Target of Rapamycin in Rat Hippocampus and Prefrontal Cortex
Several lines of evidence have demonstrated that acute administration of ketamine elicits fast-acting antidepressant effects. Moreover, tramadol also has potential antidepressant effects. The aim of this study was to investigate the effects of pretreatment with tramadol on ketamine-induced antidepressant activity and was to determine the expression of mammalian target of rapamycin (mTOR) in rat hippocampus and prefrontal cortex. Rats were intraperitoneally administrated with ketamine at the dose of 10 mg/kg or saline 1 h before the second episode of the forced swimming test (FST). Tramadol or saline was intraperitoneally pretreated 30 min before the former administration of ketamine or saline. The locomotor activity and the immobility time of FST were both measured. After that, rats were sacrificed to determine the expression of mTOR in hippocampus and prefrontal cortex. Tramadol at the dose of 5 mg/kg administrated alone did not elicit the antidepressant effects. More importantly, pretreatment with tramadol enhanced the ketamine-induced antidepressant effects and upregulated the expression of mTOR in rat hippocampus and prefrontal cortex. Pretreatment with tramadol enhances the ketamine-induced antidepressant effects, which is associated with the increased expression of mTOR in rat hippocampus and prefrontal cortex
Peripheral Leukocytapheresis Attenuates Acute Lung Injury Induced by Lipopolysaccharide In Vivo
The mortality of acute lung injury and acute respiratory distress syndrome (ALI/ARDS) remains high and efforts for prevention and treatments have shown little improvement over the past decades. The present study investigated the efficacy and mechanism of leukocytapheresis (LCAP) to partially eliminate peripheral neutrophils and attenuate lipopolysaccharide (LPS)-induced lung injury in dogs. A total of 24 healthy male mongrel dogs were enrolled and randomly divided into LPS, LCAP and LCAP-sham groups. All animals were injected with LPS to induce endotoxemia. The serum levels of leucocytes, neutrophil elastase, arterial blood gas, nuclear factor-kappa B (NF-κB) subunit p65 in lung tissues were measured. The histopathology and parenchyma apoptosis of lung tissues were examined. We found that 7, 3, and 7 animals in the LPS, LCAP, and sham-LCAP groups, respectively, developed ALI 36 h after LPS infusion. The levels of NF-κB p65 in lung tissue, neutrophils and elastase in blood, decreased significantly following LCAP. LCAP also alleviated apoptosis, and NF-κB p65 in lung tissues. Collectively, our results show that partial removal of leucocytes from peripheral blood decreases elastase level in serum. This, in turn, attenuates lung injuries and may potentially decrease the incidence of ALI
miR394 and its target gene LCR are involved in cold stress response in Arabidopsis
AbstractMicroRNA394 (miR394) and its target gene LEAF CURLING RESPONSIVENESS (LCR) are known to mediate plant growth and development. However, whether miR394 and LCR regulate plant adaptation to low temperature has not been investigated. Here, we showed that miR394a overexpressing (35S::MIR394a) plants and a LCR loss of function lcr mutant exhibited more tolerance to cold stress (4 to −11°C), whereas LCR overexpressing (35S::m5LCR) plants displayed a cold hypersensitive phenotype as compared to wild-type. Both 35S::MIR394a and lcr plants accumulated more proline and total soluble sugars under cold stress (4°C) than wild-type. Furthermore, a lower rate of electrolyte leakage was observed in 35S::MIR394a and lcr plants. These results indicated that the physiological response was changed due to the expression of miR394. However, a contrasting phenotype was found in LCR overexpressing plants. Analysis of the cold-responsive genes revealed that transcripts of CBF1, CBF2 and CBF3 (C-repeat/dehydration binding factor) were increased in the 35S::MIR394a plants relative to the wild-type, suggesting that miR394-regulated cold tolerance was involved in the CBF-dependent cold responsive pathway. Taken together, our results showed that both miR394 and its target gene LCR are involved in plant response to low temperature
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