153 research outputs found
The Differentiation and Analysis of Pivotal Construction and Similar Syntactic Constructions
Since the appearance of “pivotal construction”, scholars have always questioned its existence and wanted to classify it into the category of other syntactic constructions. Therefore, it is necessary to make a more detailed distinction between the pivotal construction and the other similar syntactic constructions. Generally, the pivotal construction can be abbreviated as N1 + V1 + N2 + V2, which is the same as in other syntactic constructions or sentence patterns: subject-predicate structure as the object construction, serial predicate construction, fused serial predicate and pivotal construction. In this paper, syntax combined with semantics, these four simple sentence patterns (syntactic constructions) are taken as examples and analyzed in detail. Finally, we draw a conclusion that N1, V1, N2, V2 have complex relationship on the syntactic structure. Meanwhile, through the semantic analysis and classification of V1, we make a clear distinction of V1 in the four types of simple sentence patterns and the relationship between V1 and V2 is clearly differentiated
Application of Benchtop NMR for Metabolomics Study Using Feces of Mice with DSS-Induced Colitis
Nuclear magnetic resonance (NMR)-based metabolomics, which comprehensively measures metabolites in biological systems and investigates their response to various perturbations, is widely used in research to identify biomarkers and investigate the pathogenesis of underlying diseases. However, further applications of high-field superconducting NMR for medical purposes and field research are restricted by its high cost and low accessibility. In this study, we applied a low-field, benchtop NMR spectrometer (60 MHz) employing a permanent magnet to characterize the alterations in the metabolic profile of fecal extracts obtained from dextran sodium sulfate (DSS)-induced ulcerative colitis model mice and compared them with the data acquired from high-field NMR (800 MHz). Nineteen metabolites were assigned to the 60 MHz 1H NMR spectra. Non-targeted multivariate analysis successfully discriminated the DSS-induced group from the healthy control group and showed high comparability with high-field NMR. In addition, the concentration of acetate, identified as a metabolite with characteristic behavior, could be accurately quantified using a generalized Lorentzian curve fitting method based on the 60 MHz NMR spectra.journal articl
Wall shear stress and its role in atherosclerosis
Atherosclerosis (AS) is the major form of cardiovascular disease and the leading cause of morbidity and mortality in countries around the world. Atherosclerosis combines the interactions of systemic risk factors, haemodynamic factors, and biological factors, in which biomechanical and biochemical cues strongly regulate the process of atherosclerosis. The development of atherosclerosis is directly related to hemodynamic disorders and is the most important parameter in the biomechanics of atherosclerosis. The complex blood flow in arteries forms rich WSS vectorial features, including the newly proposed WSS topological skeleton to identify and classify the WSS fixed points and manifolds in complex vascular geometries. The onset of plaque usually occurs in the low WSS area, and the plaque development alters the local WSS topography. low WSS promotes atherosclerosis, while high WSS prevents atherosclerosis. Upon further progression of plaques, high WSS is associated with the formation of vulnerable plaque phenotype. Different types of shear stress can lead to focal differences in plaque composition and to spatial variations in the susceptibility to plaque rupture, atherosclerosis progression and thrombus formation. WSS can potentially gain insight into the initial lesions of AS and the vulnerable phenotype that gradually develops over time. The characteristics of WSS are studied through computational fluid dynamics (CFD) modeling. With the continuous improvement of computer performance-cost ratio, WSS as one of the effective parameters for early diagnosis of atherosclerosis has become a reality and will be worth actively promoting in clinical practice. The research on the pathogenesis of atherosclerosis based on WSS is gradually an academic consensus. This article will comprehensively review the systemic risk factors, hemodynamics and biological factors involved in the formation of atherosclerosis, and combine the application of CFD in hemodynamics, focusing on the mechanism of WSS and the complex interactions between WSS and plaque biological factors. It is expected to lay a foundation for revealing the pathophysiological mechanisms related to abnormal WSS in the progression and transformation of human atherosclerotic plaques
Atrial Fibrillation Follow-up Investigation to Recover Memory and Learning Trial (AFFIRMING): Rationale and Design of a Multi-center, Double-blind, Randomized Controlled Trial
Background: People with atrial fibrillation (AF) have elevated risk of developing cognitive impairment. At present, there is a dearth of randomized controlled trials investigating cognitive impairment management in patients with AF. The Atrial Fibrillation Follow-up Investigation to Recover Memory and learning (AFFIRMING) study is aimed at evaluating the potential for computerized cognitive training to improve cognitive function in patients with AF. Methods: The study is a multi-center, double-blind, randomized controlled study using a 1:1 parallel design. A total of 200 patients with AF and mild cognitive decline without dementia are planned to be recruited. The intervention group will use the adaptive training software with changes in difficulty, whereas the positive control group will use basic training software with minimal or no variation in difficulty level. At the end of 12 weeks, the participants will be unblinded, and the positive control group will stop training. The intervention group will be rerandomized 1:1 to stop training or continue training. All participants will be followed up until 24 weeks. The primary endpoint is the proportion of the improvement of the global cognitive function at week 12 compared with baseline, using the Basic Cognitive Ability Test (BCAT)
Celastrol targets mitochondrial respiratory chain complex I to induce reactive oxygen species-dependent cytotoxicity in tumor cells
<p>Abstract</p> <p>Background</p> <p>Celastrol is an active ingredient of the traditional Chinese medicinal plant <it>Tripterygium Wilfordii</it>, which exhibits significant antitumor activity in different cancer models <it>in vitro </it>and <it>in vivo</it>; however, the lack of information on the target and mechanism of action of this compound have impeded its clinical application. In this study, we sought to determine the mode of action of celastrol by focusing on the processes that mediate its anticancer activity.</p> <p>Methods</p> <p>The downregulation of heat shock protein 90 (HSP90) client proteins, phosphorylation of c-Jun NH2-terminal kinase (JNK), and cleavage of PARP, caspase 9 and caspase 3 were detected by western blotting. The accumulation of reactive oxygen species (ROS) was analyzed by flow cytometry and fluorescence microscopy. Cell cycle progression, mitochondrial membrane potential (MMP) and apoptosis were determined by flow cytometry. Absorption spectroscopy was used to determine the activity of mitochondrial respiratory chain (MRC) complexes.</p> <p>Results</p> <p>Celastrol induced ROS accumulation, G2-M phase blockage, apoptosis and necrosis in H1299 and HepG2 cells in a dose-dependent manner. N-acetylcysteine (NAC), an antioxidative agent, inhibited celastrol-induced ROS accumulation and cytotoxicity. JNK phosphorylation induced by celastrol was suppressed by NAC and JNK inhibitor SP600125 (SP). Moreover, SP significantly inhibited celastrol-induced loss of MMP, cleavage of PARP, caspase 9 and caspase 3, mitochondrial translocation of Bad, cytoplasmic release of cytochrome c, and cell death. However, SP did not inhibit celastrol-induced ROS accumulation. Celastrol downregulated HSP90 client proteins but did not disrupt the interaction between HSP90 and cdc37. NAC completely inhibited celastrol-induced decrease of HSP90 client proteins, catalase and thioredoxin. The activity of MRC complex I was completely inhibited in H1299 cells treated with 6 ÎĽM celastrol in the absence and presence of NAC. Moreover, the inhibition of MRC complex I activity preceded ROS accumulation in H1299 cells after celastrol treatment.</p> <p>Conclusion</p> <p>We identified ROS as the key intermediate for celastrol-induced cytotoxicity. JNK was activated by celastrol-induced ROS accumulation and then initiated mitochondrial-mediated apoptosis. Celastrol induced the downregulation of HSP90 client proteins through ROS accumulation and facilitated ROS accumulation by inhibiting MRC complex I activity. These results identify a novel target for celastrol-induced anticancer activity and define its mode of action.</p
Real-time Monitoring for the Next Core-Collapse Supernova in JUNO
Core-collapse supernova (CCSN) is one of the most energetic astrophysical
events in the Universe. The early and prompt detection of neutrinos before
(pre-SN) and during the SN burst is a unique opportunity to realize the
multi-messenger observation of the CCSN events. In this work, we describe the
monitoring concept and present the sensitivity of the system to the pre-SN and
SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is
a 20 kton liquid scintillator detector under construction in South China. The
real-time monitoring system is designed with both the prompt monitors on the
electronic board and online monitors at the data acquisition stage, in order to
ensure both the alert speed and alert coverage of progenitor stars. By assuming
a false alert rate of 1 per year, this monitoring system can be sensitive to
the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos
up to about 370 (360) kpc for a progenitor mass of 30 for the case
of normal (inverted) mass ordering. The pointing ability of the CCSN is
evaluated by using the accumulated event anisotropy of the inverse beta decay
interactions from pre-SN or SN neutrinos, which, along with the early alert,
can play important roles for the followup multi-messenger observations of the
next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure
Detection of the Diffuse Supernova Neutrino Background with JUNO
As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO
Potential of Core-Collapse Supernova Neutrino Detection at JUNO
JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve
Enhanced CuAl<sub>2</sub>O<sub>4</sub> Catalytic Activity via Alkalinization Treatment toward High CO<sub>2</sub> Conversion during Reverse Water Gas Shift Reaction
CO2 catalytic conversion to CO would likely be an important part of CO2 mitigation and utilization. In this work, CuAl2O4 was developed with a spinel structure that acts as an active and stable catalyst for this reaction. Here, the fundamental characteristics of CuAl2O4 catalyst were studied to understand the catalytic mechanism for the Reverse Water Gas Shift reaction. Based on the catalytic mechanism, the CuAl2O4 catalyst was found to have exceptional catalytic activity due to the high dispersion of copper on its surface, and it could have higher catalytic activity by increasing the oxygen vacancies on the surface of the catalyst via alkalinization treatment. By combining with XPS spectra, the relationship between the Raman mode and the oxygen vacancy structure on the CuAl2O4 surface was proved. Through these studies, it was proved that alkalinization treatment can regulate the oxygen vacancies on the surface of the catalyst and thus enhance the catalytic activity
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