1,341 research outputs found
The research on the performance of linear ultrasonic motor under different temperature
Linear ultrasonic motor (LUSM) is a new type of driver. LUSM has many advantages, so it is taken seriously in aeronautics and astronautics. But, because of the deficiency of studies on the performance of LUSM in abnormal temperature, it’s necessary to do research on the performance of LUSM in different ambient temperature, to confirm whether it can work under abnormal temperature and how it works. In this research, we use V type LUSM (VLUSM) as the test object, owing to that VLUSM is one basic type of linear ultrasonic motor. When doing research, we pay close attention to the moment of force and the rotation rate of VLUSM, to discover how much they change in abnormal temperature environment. This research compares all datum partitioned by different temperature, and uses figures to show the tendency of those mechanical properties in abnormal temperature. At the same time, we explain the changing by means of theories. Finally, through detailed experimental demonstration, we believe that as the temperature rises, both moment of force and rotation rate of VLUSM increase, and we can also conclude that VLUSM can work normally under abnormal temperature environment
Adiponectin protects against paraquat-induced lung injury by attenuating oxidative/nitrative stress.
The specific mechanisms underlying paraquat (PQ)-induced lung injury remain unknown, which limits understanding of its cytotoxic potential. Although oxidative stress has been established as an important mechanism underlying PQ toxicity, multiple antioxidants have proven ineffective in attenuating the deleterious effects of PQ. Adiponectin, which shows anti-oxidative and antinitrative effects, may have the potential to reduce PQ-mediated injury. The present study determined the protective action of globular domain adiponectin (gAd) on PQ-induced lung injury, and attempted to elucidate the underlying mechanism or mechanisms of action. BALB/c mice were administered PQ, with and without 12 or 36 h of gAd pre-treatment. The pulmonary oxidative/nitrative status was assessed by measuring pulmonary O2(•-), superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO) and 8-hydroxy-2-dydeoxy guanosine (8-OHdG) production, and blood 3-Nitrotyrosine (3-NT). At a dose of 20 mg/kg, PQ markedly increased O2(•-), SOD, MDA, NO and 8-OHdG production 3 h post-administration, but did not significantly increase 3-NT levels until 12 h. gAd inhibited these changes in a dose-dependent manner, via transient activation of MDA, followed by attenuation of MDA formation from 6 h onwards. Histological analysis demonstrated that gAd decreased interstitial edema and inflammatory cell infiltration. These results suggest that gAd protects against PQ-induced lung injury by mitigating oxidative/nitrative stress. Furthermore, gAd may be a potential therapeutic agent for PQ-induced lung injury, and further pharmacological studies are therefore warranted
The research on the performance of linear ultrasonic motor under different temperature
Linear ultrasonic motor (LUSM) is a new type of driver. LUSM has many advantages, so it is taken seriously in aeronautics and astronautics. But, because of the deficiency of studies on the performance of LUSM in abnormal temperature, it’s necessary to do research on the performance of LUSM in different ambient temperature, to confirm whether it can work under abnormal temperature and how it works. In this research, we use V type LUSM (VLUSM) as the test object, owing to that VLUSM is one basic type of linear ultrasonic motor. When doing research, we pay close attention to the moment of force and the rotation rate of VLUSM, to discover how much they change in abnormal temperature environment. This research compares all datum partitioned by different temperature, and uses figures to show the tendency of those mechanical properties in abnormal temperature. At the same time, we explain the changing by means of theories. Finally, through detailed experimental demonstration, we believe that as the temperature rises, both moment of force and rotation rate of VLUSM increase, and we can also conclude that VLUSM can work normally under abnormal temperature environment
Changes in Climate Extremes and Catastrophic Events in the Mongolian Plateau from 1951 to 2012
AbstractThe spatiotemporal changes in 21 indices of extreme temperature and precipitation for the Mongolian Plateau from 1951 to 2012 were investigated on the basis of daily temperature and precipitation data from 70 meteorological stations. Changes in catastrophic events, such as droughts, floods, and snowstorms, were also investigated for the same period. The correlations between catastrophic events and the extreme indices were examined. The results show that the Mongolian Plateau experienced an asymmetric warming trend. Both the cold extremes and warm extremes showed greater warming at night than in the daytime. The spatial changes in significant trends showed a good homogeneity and consistency in Inner Mongolia. Changes in the precipitation extremes were not as obvious as those in the temperature extremes. The spatial distributions in changes of precipitation extremes were complex. A decreasing trend was shown for total precipitation from west to east as based on the spatial distribution of decadal trends. Drought was the most serious extreme disaster, and prolonged drought for longer than 3 yr occurred about every 7–11 yr. An increasing trend in the disaster area was apparent for flood events from 1951 to 2012. A decreasing trend was observed for the maximum depth of snowfall from 1951 to 2012, with a decreased average maximum depth of 10 mm from the 1990s.</jats:p
Eucomic acid methanol monosolvate
In the crystal structure of the title compound [systematic name: 2-hyÂdroxy-2-(4-hyÂdroxyÂbenzÂyl)butaneÂdioic acid methanol monosolvate], C11H12O6·CH3OH, the dihedral angles between the planes of the carboxyl groups and the benzene ring are 51.23 (9) and 87.97 (9)°. InterÂmolecular O—H⋯O hydrogen-bonding interÂactions involving the hyÂdroxy and carbÂoxyÂlic acid groups and the methanol solvent molÂecule give a three-dimensional structure
Gemcitabine enhances cell invasion via activating HAb18G/CD147-EGFR-pSTAT3 signaling
Pancreatic cancer, one of the most lethal cancers, has very poor 5-year survival partly due to gemcitabine resistance. Recently, it was reported that chemotherapeutic agents may act as stressors to induce adaptive responses and to promote chemoresistance in cancer cells. During long-term drug treatment, the minority of cancer cells survive and acquire an epithelial-mesenchymal transition phenotype with increased chemo-resistance and metastasis. However, the short-term response of most cancer cells remains unclear. This study aimed to investigate the short-term response of pancreatic cancer cells to gemcitabine stress and to explore the corresponding mechanism. Our results showed that gemcitabine treatment for 24 hours enhanced pancreatic cancer cell invasion. In gemcitabine-treated cells, HAb18G/CD147 was up-regulated; and HAb18G/CD147 down-regulation or inhibition attenuated gemcitabine-enhanced invasion. Mechanistically, HAb18G/CD147 promoted gemcitabine-enhanced invasion by activating the EGFR (epidermal growth factor receptor)-STAT3 (signal transducer and activator of transcription 3) signaling pathway. Inhibition of EGFR-STAT3 signaling counteracted gemcitabine-enhanced invasion, and which relied on HAb18G/CD147 levels. In pancreatic cancer tissues, EGFR was highly expressed and positively correlated with HAb18G/CD147. These data indicate that pancreatic cancer cells enhance cell invasion via activating HAb18G/CD147-EGFR-pSTAT3 signaling. Our findings suggest that inhibiting HAb18G/CD147 is a potential strategy for overcoming drug stress-associated resistance in pancreatic cancer
Seeing Differently, Acting Similarly: Imitation Learning with Heterogeneous Observations
In many real-world imitation learning tasks, the demonstrator and the learner
have to act in different but full observation spaces. This situation generates
significant obstacles for existing imitation learning approaches to work, even
when they are combined with traditional space adaptation techniques. The main
challenge lies in bridging expert's occupancy measures to learner's dynamically
changing occupancy measures under the different observation spaces. In this
work, we model the above learning problem as Heterogeneous Observations
Imitation Learning (HOIL). We propose the Importance Weighting with REjection
(IWRE) algorithm based on the techniques of importance-weighting, learning with
rejection, and active querying to solve the key challenge of occupancy measure
matching. Experimental results show that IWRE can successfully solve HOIL
tasks, including the challenging task of transforming the vision-based
demonstrations to random access memory (RAM)-based policies under the Atari
domain.Comment: 17 pages, 25 figure
- …