The hyperon mean free paths in the relativistic mean field

The $\Lambda$- and $\Xi^-$-hyperon mean free paths in nuclei are firstly calculated in the relativistic mean field (RMF) theory. The real parts of the optical potential are derived from the RMF approach, while the imaginary parts are obtained from those of nucleons with the relations: $U^{\mathrm{IY}}_{\mathrm{S}} = \alpha_{\sigma \mathrm{Y}}\cdot U_{\mathrm{S}}^{\mathrm{IN}}$ and $U^{\mathrm{IY}}_{\mathrm{V}} = \alpha_{\omega \mathrm{Y}}\cdot U_{\mathrm{V}}^{\mathrm{IN}}$ . With the assumption, the depth of the imaginary potential for $\Xi^-$ is $W_{\Xi}\simeq-$ 3.5 MeV, and for $\Lambda$ is $W_{\Lambda}\simeq-$ 7 MeV at low incident energy. We find that, the hyperon mean free path decreases with the increase of the hyperon incident energies, from 200 MeV to 800 MeV; and in the interior of the nuclei, the mean free path is about $2\sim 3$ fm for $\Lambda$, and about $4\sim 8$ fm for $\Xi^-$, depending on the hyperon incident energy.Comment: 5 figures, 6 page

Evolution of river regimes in the Mekong River basin over 8 decades and the role of dams in recent hydrological extremes

Flow regimes in major global river systems are undergoing rapid alterations due to unprecedented stress from climate change and human activities. The Mekong River basin (MRB) was, until recently, among the last major global rivers relatively unaltered by humans, but this has been changing alarmingly in the last decade due to booming dam construction. Numerous studies have examined the MRB's flood pulse and its alterations in recent years. However, a mechanistic quantification at the basin scale attributing these changes to either climatic or human drivers is lacking. Here, we present the first results of the basin-wide changes in natural hydrological regimes in the MRB over the past 8 decades and the impacts of dams in recent decades by examining 83 years (1940–2022) of river regime characteristics simulated by a river–floodplain hydrodynamic model that includes 126 major dams in the MRB. Results indicate that, while the Mekong River's flow has shown substantial decadal trends and variabilities, the operation of dams in recent years has been causing a fundamental shift in the seasonal volume and timing of river flow and extreme hydrological conditions. Even though the dam-induced impacts have been small so far and most pronounced in areas directly downstream of major dams, dams are intensifying the natural variations in the Mekong's mainstream wet-season flow. Further, the additional 65 dams commissioned since 2010 have exacerbated drought conditions by substantially delaying the MRB's wet-season onset, especially in recent years (e.g., 2019 and 2020), when the natural wet-season durations are already shorter than in normal years. Further, dams have shifted by up to 20 % of the mainstream annual volume between the dry and wet seasons in recent years. While this has a minimal impact on the MRB's annual flow volume, the flood occurrence in many major areas of Tonlé Sap and the Mekong Delta has been largely altered. This study provides critical insights into the long-term hydrological variabilities and impacts of dams on the Mekong River's flow regimes, which can help improve water resource management in light of intensifying hydrological extremes.</p

Anti-hyperlipidemic effect of flavone-rich Belamcanda chinensis (L.) DC. (Iridaceae) leaf extract in ICR mice fed high-fat diet

Purpose: To assess the anti-hyperlidemic effect of flavone-rich B. chinensis leaf extract (HTP) in ICR mice fed a high-fat diet.Methods: HTP (100, 200 and 400 mg/kg) were orally administered to ICR mice fed high-fat diet for 7 weeks. Blood glucose, as well as serum and hepatic levels of lipids were determined at the end of the experiment. Phosphorylation of adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK) and protein level of peroxisome proliferator-activated receptor α (PPARα) were analyzed by Western blot and enzyme-linked immunosorbent assay (ELISA) kit, respectively.Results: Treatment with HTP significantly decreased peri-epididymal fat weight (p &lt; 0.01 and p &lt; 0.05 for 200 and 100 mg/kg, respectively), lowered serum and hepatic lipid, and decreased glucose area under curve (AUC) in oral glucose tolerance test (p &lt; 0.01 for 200 mg/kg). Western blot and ELISA analysis showed that administration of HTP (200 mg/kg) significantly increased AMPK (p &lt; 0.05) phosphorylation and PPARα expression in liver (p &lt; 0.05).Conclusion: HTP can alleviate hyperlipidemia, at least in part, by up-regulation of AMPK and PPARα.Keywords: Belamcanda chinensis, Flavone, Hyperlipidemia, Adenosine 5′-monophosphate-activated protein kinase, Peroxisome proliferator activated receptor-alpha, Glucose toleranc

Understanding the critical role of boundary conditions in meso-scale finite element simulation of braided composites

A reasonable boundary condition for the meso-scale finite element (FE) simulation of textile composites is necessary for model validation against experiments, which is sometimes over-simplified for saving computation time. This paper examines the influence of boundary conditions on the global stress–strain response and deformation pattern, as well as the local damage and failure characters, through systematically comparison studies of numerical results against experimental results under different loading conditions. The results suggest that reasonable application of periodic boundary conditions can effectively improve the calculation efficiency, and the employment of symmetric boundary conditions along the loading direction will cause the undesired strain concentration and premature damage at the loading edges of the model. Besides, extra constraints along the thickness direction may restrain the normal out-of-plane deformation of the braided composites and thereby cause an overestimation of the transverse strengths. Graphical abstract: [Figure not available: see fulltext.]

Synchronized and Desynchronized Phases of Exciton-Polariton Condensates in the Presence of Disorder

Condensation of exciton-polaritons in semiconductor microcavities takes place despite in plane disorder. Below the critical density the inhomogeneity of the potential seen by the polaritons strongly limits the spatial extension of the ground state. Above the critical density, in presence of weak disorder, this limitation is spontaneously overcome by the non linear interaction, resulting in an extended synchronized phase. This mechanism is clearly evidenced by spatial and spectral studies, coupled to interferometric measurements. In case of strong disorder, several non phase-locked (independent) condensates can be evidenced. The transition from synchronized phase to desynchronized phase is addressed considering multiple realizations of the disorder.Comment: 11 pages, 4 figures,corrected typos, added figure

Photocatalytic Nitrogen Reduction by Ti₃C₂ MXene Derived Oxygen Vacancy‐Rich C/TiO₂

In this work, oxygen vacancy‐rich C/TiO_{2} (OV‐C/TiO_{2}) samples are prepared by a one‐step calcination approach using Ti_{3}C_{2} MXene as the precursor, and used for the photocatalytic N_{2} reduction. The NH_{3} yields of all the prepared OV‐C/TiO_{2} samples exceed those achieved on commercial anatase TiO_{2} and P25, with both H_{2}O and CH_{3}OH as the proton sources. Among them, the OV‐C/TiO_{2}‐600 offers the remarkable NH3 synthesis rates, which are 41.00 µmol g^{−1} h^{−1} (with CH_{3}OH as the proton source). The photocurrent and fluorescence spectra show that OV‐C/TiO_{2}‐600 exhibit the highest generation/separation rate and longest lifetime of photocarriers among all the prepared samples. ESR and TPD experiments confirm much more efficient chemisoption of N_{2} on the surface of the prepared OV‐C/TiO_{2}‐600 than that on the surface of the commercial anatase TiO_{2}. Moreover, DFT calculations further demonstrate that N2 conversion to NH_{3} through a Gibbs free energy release leading alternating pathway with a low energy barriers, on the oxygen vacancy on TiO_{2} surface

The cystic fibrosis transmembrane conductance regulator impedes proteolytic stimulation of the epithelial Na+ channel

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) that prevent its proper folding and trafficking to the apical membrane of epithelial cells. Absence of cAMP-mediated Cl- secretion in CF airways causes poorly hydrated airway surfaces in CF patients, and this condition is exacerbated by excessive Na+ absorption. The mechanistic link between missing CFTR and increased Na+ absorption in airway epithelia has remained elusive, although substantial evidence implicates hyperactivity of the epithelial Na+ channel (ENaC). ENaC is known to be activated by selective endoproteolysis of the extracellular domains of its α- and γ-subunits, and it was recently reported that ENaC and CFTR physically associate in mammalian cells. We confirmed this interaction in oocytes by co-immunoprecipitation and found that ENaC associated with wild-type CFTR was protected from proteolytic cleavage and stimulation of open probability. In contrast, ΔF508 CFTR, the most common mutant protein in CF patients, failed to protect ENaC from proteolytic cleavage and stimulation. In normal airway epithelial cells, ENaC was contained in the anti-CFTR immunoprecipitate. In CF airway epithelial cultures, the proportion of full-length to total α-ENaC protein signal was consistently reduced compared with normal cultures. Our results identify limiting proteolytic cleavage of ENaC as a mechanism by which CFTR down-regulates Na+ absorption

Silicon-based III-V quantum-dot laser for silicon photonics

Monolithic III-V materials grown on Si is a promising platform for silicon photonics. Here, by investigating the laser performance of two conventional III-V quantum structures on Si, namely quantumdots and quantum-well, we unambiguously demonstrate the excellence and suitability of quantum-dots over quantum-well in silicon-based laser structure and reveal the physical mechanisms underneath, which is attributed to the better tolerance characteristic of quantum-dots for optically detrimental defects. Our work shows that monolithic III-V quantum-dot lasers on Si are the most promising light source for silicon photonics technology

Interference Mitigation for the GPS Receiver Utilizing the Cyclic Spectral Analysis and RR-MSWF Algorithm

A method utilizing the cyclic spectral analysis (CSA) and reduced-rank multistage Wiener filtering (RR-MSWF) algorithm to mitigate the interference for the GPS receiver is proposed. In many cases, interference from adjacent channel or from cochannel overlaps on the weak global positioning system (GPS) signal in both time and frequency domains, and it is hard to mitigate this kind of strong interference with the conventional filtering techniques. While with the proposed method given in the paper, we can mitigate the interference effectively. The general process of the proposed method is that first we get the cyclic frequencies (CFs) of the strong interference by CSA of the received GPS signal. And then with the obtained CFs of the interference, we use the blind adaptive frequency shift (BA-FRESH) filter to get the principal process of mitigating the strong interference and separating the weak GPS signal. Finally by utilizing the efficient RR-MSWF algorithm to implement the BA-FRESH filtering, we can mitigate the strong interference effectively and hence improve the performance of the GPS receiver