We have observed a new deformation-twinning mechanism using the high resolution transmission electron microscope in polycrystalline Ag films, zero-strain twinning via nucleation, and the migration of ...a Σ3{112} incoherent twin boundary (ITB). This twinning mechanism produces a near zero macroscopic strain because the net Burgers vectors either equal zero or are equivalent to a Shockley partial dislocation. This observation provides new insight into the understanding of deformation twinning and confirms a previous hypothesis: detwinning could be accomplished via the nucleation and migration of Σ3{112} ITBs. The zero-strain twinning mechanism may be unique to low staking fault energy metals with implications for their deformation behavior.
Summary Objective Hypoxia-inducible factor-2α (HIF-2α) transcriptionally upregulates Nampt in articular chondrocytes. NAMPT, which exhibits nicotinamide phosphoribosyltransferase activity, in turn ...causes osteoarthritis (OA) in mice by stimulating the expression of matrix-degrading enzymes. Here, we sought to elucidate whether HIF-2α activates the NAMPT-NAD+ -SIRT axis in chondrocytes and thereby contributes to the pathogenesis of OA. Methods Assays of NAD levels, SIRT activity, reporter gene activity, mRNA, and protein levels were conducted in primary cultured mouse articular chondrocytes. Experimental OA in mice was induced by intra-articular (IA) injection of adenovirus expressing HIF-2α (Ad- Epas1 ) or NAMPT (Ad- Nampt ). The functions of SIRT in OA were examined by IA co-injection of SIRT inhibitors or adenovirus expressing individual SIRT isoforms or shRNA targeting specific SIRT isoforms. Results HIF-2α activated the NAMPT-NAD+ -SIRT axis in chondrocytes by upregulating NAMPT, which stimulated NAD+ synthesis and thereby activated SIRT family members. The activated NAMPT-SIRT pathway, in turn, promoted HIF-2α protein stability by negatively regulating its hydroxylation and 26S proteasome-mediated degradation, resulting in increased HIF-2α transcriptional activity. Among SIRT family members (SIRT1–7), SIRT2 and SIRT4 were positively associated with HIF-2α stability and transcriptional activity in chondrocytes. This reciprocal regulation was required for the expression of catabolic matrix metalloproteinases (MMP3, MMP12, and MMP13) and OA cartilage destruction caused by IA injection of Ad- Epas1 Ad- Nampt. Conclusion The reciprocal regulation of HIF-2α and the NAMPT-NAD+ -SIRT axis in articular chondrocytes is involved in OA cartilage destruction caused by HIF-2α or NAMPT.
The prevalence of renal cell carcinoma is increasing in recent years. With the development of research, we know more about the mechanism and biological characteristics of renal cell carcinoma. ...Currently, the most used prognosis evaluation methods are clinical factors based prognostic prediction models. New drugs, typified by the checkpoint inhibitors, have achieved great success in the treatment of renal cell carcinoma, on the basis of traditional tyrosine kinase inhibitor. With recognition of more prognosis and treatment related biomarkers, directive role for the prognosis prediction and treatment options could be expected.
Objectives
Cognitive frailty was notable target for the prevention of adverse health outcomes in future. The goal of this study was to use a population-based survey to investigate cognitive frailty ...phenotypes and potentially sociodemographic factors in elderly Chinese individuals.
Design
Cross-sectional study.
Setting
General community.
Participants
A total of 5328 elderly adults (aged 60 years or older, mean age 71.36 years) enrolled in the Shanghai study of health promotion for elderly individuals with frailty.
Measurements
The 5-item FRAIL scale and the 3-item Rapid Cognitive Screen tools were used to assess physical frailty and cognitive impairment, including dementia or mild cognitive impairment (MCI). Physical frailty was diagnosed by limitations in 3 or more of the FRAIL scale domains and pre-physical frailty by 1–2 limitations. Subjective cognitive decline (SCD) and pre-MCI SCD, was diagnosed with two self-report measures based on memory and other cognitive domains in elderly adults.
Results
Of the participating individuals, 97.17% (n= 5177, female 53.4%) were eligible. Notably, 9.67%, 41.61% and 35.20% of participants were MCI, SCD and pre-MCI SCD; 35.86% and 4.41% exhibited physical pre-frailty and frailty; and 19.86% and 6.30% exhibited reversible and potential reversible cognitive frailty. Logistic regression analyses indicated that physical frailty phenotypes were significantly associated with MCI with SCD, and pre-MCI with SCD. Older single females with a high education level were more likely to exhibit the reversible cognitive frailty; and younger elderly individuals with a middle education level were at lower risk for potentially reversible cognitive frailty.
Conclusions
The prevalence of pre-physical and reversible cognitive frailty was high in elderly individuals and age was the most significant risk factor for all types of frailty phenotypes. To promote the rapid screening protocol of cognitive frailty in community-dwelling elderly is important to find high-risk population, implement effective intervention, and decrease adverse prognosis.
Rice husk (RH) has now become a source for a number of silicon compounds, including silicon carbide, silica, silicon nitride, silicon tetrachloride, zeolite, and pure silicon. The applications of ...such materials derived from rice husks are very comprehensive. The methods of synthesizing these silicon-based materials from RHs and their applications are reviewed in this paper.
Nowadays, multiple-view stereo satellite imagery has become a valuable data source for digital surface model generation and 3D reconstruction. In 2016, a well-organized multiple view stereo publicly ...benchmark for commercial satellite imagery has been released by the John Hopkins University Applied Physics Laboratory, USA. This benchmark motivates us to explore the method that can generate accurate digital surface models from a large number of high resolution satellite images. In this paper, we propose a pipeline for processing the benchmark data to digital surface models. As a pre-procedure, we filter all the possible image pairs according to the incidence angle and capture date. With the selected image pairs, the relative bias-compensated model is applied for relative orientation. After the epipolar image pairs’ generation, dense image matching and triangulation, the 3D point clouds and DSMs are acquired. The DSMs are aligned to a quasi-ground plane by the relative bias-compensated model. We apply the median filter to generate the fused point cloud and DSM. By comparing with the reference LiDAR DSM, the accuracy, the completeness and the robustness are evaluated. The results show, that the point cloud reconstructs the surface with small structures and the fused DSM generated by our pipeline is accurate and robust.
Carbon dioxide is considered an inert gas that rarely participates in atmospheric chemical reactions. Nonetheless, we show here that CO2 is involved in some important photo-oxidation reactions in the ...atmosphere through the formation of carbonate radicals (CO3⚫-). This potentially active intermediate CO3⚫- is routinely overlooked in atmospheric chemistry concerning its effect on sulfate formation. The present work demonstrates that the SO2 uptake coefficient is enhanced by 17 times on mineral dust particles driven by CO3⚫-. Importantly, upon irradiation, mineral dust particles are speculated to produce gas-phase carbonate radical ions when the atmospherically relevant concentration of CO2 presents, thereby potentially promoting external sulfate aerosol formation and oxidative potential in the atmosphere. Employing a suite of laboratory investigations of sulfate formation in the presence of carbonate radicals on the model and authentic dust particles, ground-based field measurements of sulfate and (bi)carbonate ions within ambient PM, together with density functional theory (DFT) calculations for single electron transfer processes in terms of CO3⚫--initiated S(IV) oxidation, a novel role of carbonate radical in atmospheric chemistry is elucidated.
ABSTRACT
High time resolution and accuracy are of critical importance in the studies of timing analysis and time delay localization of gamma-ray bursts (GRBs), soft gamma-ray repeaters (SGRs) and ...pulsars. The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) consisting of two micro-satellites, GECAM-A and GECAM-B, launched on 2020 December 10, is aimed at monitoring and locating X-ray and GRBs all over the sky. To achieve its scientific goals, GECAM is designed to have the highest time resolution (0.1 $\mu {\rm s}$) among all GRB detectors ever flown. Here, we make a comprehensive time calibration campaign including both on-ground and on-orbit tests to derive not only the relative time accuracy of GECAM satellites and detectors, but also the absolute time accuracy of GECAM-B. Using the on-ground calibration with a $\rm ^{22}Na$ radioactive source, we find that the relative time accuracy between GECAM-A and GECAM-B is about 0.15 $\mu {\rm s}$ (1σ). To measure the relative time accuracy between all detectors of a single GECAM satellite, cosmic-ray events detected on orbit are utilized since they could produce many secondary particles simultaneously record by multiple detectors. We find that the relative time accuracy among all detectors onboard GECAM-B is about 0.12 $\mu {\rm s}$ (1σ). Finally, we use the novel Li-CCF method to perform the absolute time calibration with Crab pulsar and SGR J1935+2154, both of which were jointly observed by GECAM-B and Fermi/GBM, and obtain that the time difference between GECAM-B and Fermi/GBM is 3.06 ± 6.04 $\mu {\rm s}$ (1σ).
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