793 research outputs found
Numerical Investigation for the Bearing Performance of the Segmental Joint with Elastic Gasket
Detailed three-dimensional numerical models considering concrete indentation, bolts, elastic gasket (EG) and sealing gasket (SG) are established for the segmental joint with gaskets, and the load tests of the joints with EG and without EG are simulated and compared. The results reveal that the bearing performance of the joint with EG is very complex. In sagging moment scenarios, it can be divided into four stages by three key points “EG starts to open”, “joint external edge starts to contact” and “EG fully opened”. In hogging moment scenarios, it can be divided into three stages by two key points “SG opened” and “EG starts to open”. The EG has a significant effect on the joint bearing performance. It can soften the joint, which leads to the result that the average bending stiffness and ultimate bearing capacity of the joint with EG are evidently smaller and weaker than those of the joint without EG. With decreasing the joint axial force, this softening effect tends to be more obvious. Besides, for the two joints, the ultimate states of the joints subject to the bending moments are both that the concrete at the joint edges yields firstly, and it is necessary to protect or strengthen the corresponding concrete
Enhanced quantum sensing with amplification and deamplification
Quantum sensing is a fundamental building block of modern technology that
employs quantum resources and creates new opportunities for precision
measurements. However, previous methods usually have a common assumption that
detection noise levels should be below the intrinsic sensitivity provided by
quantum resources. Here we report the first demonstration of Fano resonance
between coupled alkali-metal and noble gases through rapid spin-exchange
collisions. The Fano resonance gives rise to two intriguing phenomena: spin
amplification and deamplification, which serve as crucial resources for
enhanced sensing. Further we develop a novel scheme of quantum sensing enhanced
by amplification and deamplification, with relaxed requirements on the
detection noise. The coupled systems of alkali-metal and noble gases act as
amplifiers or de-amplifiers, enabling to extract small signals above the
detection noise before final detection. We demonstrate magnetic-field
measurement about 54 decibels below the photon-shot noise, which outperforms
the state-of-the-art squeezed-light technology and realizes femtotesla-level
sensitivity. Our work opens new avenues to applications in searches for
ultralight dark matter with sensitivity well beyond the supernova-observation
constraints.Comment: 7 pages, 4 figure
Cooperative Spin Amplification
Quantum amplification is recognized as a key resource for precision
measurements. However, most conventional paradigms employ an ensemble of
independent particles that usually limit the performance of quantum
amplification in gain, spectral linewidth, etc. Here we demonstrate a new
signal amplification using cooperative 129Xe nuclear spins embedded within a
feedback circuit, where the noble-gas spin coherence time is enhanced by at
least one order of magnitude. Using such a technique, magnetic field can be
substantially pre-enhanced by more than three orders and is in situ readout
with an embedded 87Rb magnetometer. We realize an ultrahigh magnetic
sensitivity of 4.0 fT/Hz that surpasses the photon-shot noise and even
below the spin-projection noise of the embedded atomic magnetometer, allowing
for exciting applications including searches for dark matter with sensitivity
well beyond supernova constraints. Our findings extend the physics of quantum
amplification to cooperative spin systems and can be generalized to a wide
variety of existing sensors, enabling a new class of cooperative quantum
sensors.Comment: 7 pages, 4 figure
Tuber indicum and T. lijiangense colonization differentially regulates plant physiological responses and mycorrhizosphere bacterial community of Castanopsis rockii seedlings
Black truffles and white truffles are widely studied around the world, but their effects on plant growth and physiological responses, and on the mycorrhizosphere bacterial community of the host plant remain unclear. Here, mycorrhizal colonization of Castanopsis rockii by Tuber indicum (Chinese black truffle) and T. lijiangense (Chinese white truffle), respectively, was induced in a greenhouse study, and their effects on host growth, physiological responses and mycorrhizosphere bacterial communities were compared. The results show that colonization of both Tuber species significantly increased leaf photosynthetic rate, leaf P concentration and mycorrhizosphere acid phosphatase activity, as well as richness of mycorrhizosphere bacterial communities of C. rockii seedlings. However, T. indicum colonization on the one hand significantly decreased tartrate content, bacterial acid phosphatase, phoC gene abundance in the mycorrhizosphere, and peroxidase (POD) activity of ectomycorrhizal root tips, but on the other hand increased mycorrhizosphere pH and superoxide dismutase (SOD) of ectomycorrhizal root tips, compared to T. lijiangense colonization. Moreover, principal coordinate and β-diversity analyses show significant differences in mycorrhizosphere bacterial community composition between T. indicum and T. lijiangese colonized C. rockii seedlings. Finally, the relative abundance of the bacterium Agromyces cerinus significantly correlated to mycorrhizosphere acid phosphatase activity and leaf P concentration, suggesting that this bacterium might play an important role in P mobilization and acquisition. Overall, these results suggest that T. indicum and T. lijiangense differently regulate their host plant’s physiological responses and mycorrhizosphere bacterial community
Improving student engagement using a video-enabled activity-based learning: an exploratory study to STEM preparatory education in UAE
Student engagement is often labelled the “holy grail of learning” (Sinatra, Heddy and Lombardi, 2015: 1). Higher education educators have been implementing different pedagogical approaches to promote active learning with the aim of improving student engagement. This paper proposes an activity -based learning approach with the use of educational video to promote student engagement. We evaluate if such an approach could improve student learning and engagement with STEM subject from three perspectives: students’ motivation, engagement, and academic performance. The main findings are in supportive of the video-enabled activity-based learning approach to promote students’ engagement within class and for future study. ANOVA tests demonstrate the significant differences in the students’ performance with the use of scientific educational videos. In addition, this UAE based exploratory case study has been conducted in the context of middle eastern students’ learning behavior which adds an interesting cultural dimension. This study contributes to knowledge and STEM educator by providing them with insightful and practical guidance on how to effectively use scientific educational video to enhance STEM education in UAE.
Origin of non-uniform plasticity in a high-strength Al-Mn-Sc based alloy produced by laser powder bed fusion
Knockout of Nr2e3 prevents rod photoreceptor differentiation and leads to selective L-/M-cone photoreceptor degeneration in zebrafish
An update on the functional roles of long non‑coding RNAs in ischemic injury (Review)
Ischemic injuries result from ischemia and hypoxia in cells. Tissues and organs receive an insufficient supply of nutrients and accumulate metabolic waste, which leads to the development of inflammation, fibrosis and a series of other issues. Ischemic injuries in the brain, heart, kidneys, lungs and other organs can cause severe adverse effects. Acute renal ischemia induces acute renal failure, heart ischemia induces myocardial infarction and cerebral ischemia induces cerebrovascular accidents, leading to loss of movement, consciousness and possibly, life-threatening disabilities. Existing evidence suggests that long non-coding RNAs (lncRNAs) are regulatory sequences involved in transcription, post-transcription, epigenetic regulation and multiple physiological processes. lncRNAs have been shown to be differentially expressed following ischemic injury, with the severity of the ischemic injury being affected by the upregulation or downregulation of certain types of lncRNA. The present review article provides an extensive summary of the functional roles of lncRNAs in ischemic injury, with a focus on the brain, heart, kidneys and lungs. The present review mainly summarizes the functional roles of lncRNA MALAT1, lncRNA MEG3, lncRNA H19, lncRNA TUG1, lncRNA NEAT1, lncRNA AK139328 and lncRNA CAREL, among which lncRNA MALAT1, in particular, plays a crucial role in ischemic injury and is currently a hot research topic
Dihydromyricetin attenuates depressive-like behaviors in mice by inhibiting the AGE-RAGE signaling pathway
Depression is a complex mental disorder, affecting approximately 280 million individuals globally. The pathobiology of depression is not fully understood, and the development of new treatments is urgently needed. Dihydromyricetin (DHM) is a natural flavanone, mainly distributed in Ampelopsis grossedentata. DHM has demonstrated a protective role against cardiovascular disease, diabetes, liver disease, cancer, kidney injury and neurodegenerative disorders. In the present study, we examined the protective effect of DHM against depression in a chronic depression mouse model induced by corticosterone (CORT). Animals exposed to CORT displayed depressive-like behaviors; DHM treatment reversed these behaviors. Network pharmacology analyses showed that DHM’s function against depression involved a wide range of targets and signaling pathways, among which the inflammation-linked targets and signaling pathways were critical. Western blotting showed that CORT-treated animals had significantly increased levels of the advanced glycation end product (AGE) and receptor of AGE (RAGE) in the hippocampus, implicating activation of the AGE-RAGE signaling pathway. Furthermore, enzyme-linked immunosorbent assay (ELISA) detected a marked increase in the production of proinflammatory cytokines, interleukin-1 beta (IL-1β), IL-6 and tumor necrosis factor-alpha (TNFα) in the hippocampus of CORT-treated mice. DHM administration significantly counteracted these CORT-induced changes. These findings suggest that protection against depression by DHM is mediated by suppression of neuroinflammation, predominantly via the AGE-RAGE signaling pathway
- …