儿童下气道菌群多样性及其对支气管哮喘辅助性T细胞分化机制影响研究进展

哮喘是由多种细胞(如嗜酸性粒细胞、肥大细胞、T淋巴细胞、中性粒细胞、气道上皮细胞等)和细胞组分参与的以慢性气道炎症和气道高反应性为特征的一种异质性疾病[1]。近年来哮喘发病率逐年攀升,据全球哮喘防治创议(GINA)委员会调查显示,全球约有3亿人受到哮喘困扰[2],世界卫生组织(WHO)预计至2025年全世界哮喘患者将会增至4亿人。研究发现,哮喘患者气道菌群在丰度及多样性等方面与正常人存在显著差异[3],而

LncRNA<italic>-PVT1/</italic>miR-15a<italic>/Bmi-1</italic>通路调控HGC-27胃癌细胞的体外增殖

目的探讨lncRNA-PVT1/miR-15a/Bmi-1通路在胃癌细胞体外增殖中的调控作用。方法分别研究PVT1，miR-15a及Bmi-1在HGC-27胃癌细胞体外增殖中的作用。体外培养的人胃癌细胞株HGC-27分为如下组别：①空白对照组、si-PVT1（转染PVT1 siRNA）和si-PVT1 NC（转染PVT1 siRNA scramble阴性对照）；②空白对照组、miR-15a（转染miR-15a模拟物）和miR-15a NC（转染miR-15a模拟物的阴性对照）。③空白对照组、si-Bmi-1（转染Bmi-1的siRNA）和si-Bmi-1 NC（转染Bmi-1的siRNA scramble阴性对照）。采用MTS法检测上述组别的细胞增殖情况。在抑制PVT1后检测不同组别PVT1、miR-15a和Bmi-1的表达情况。为验证miR-15a与Bmi-1之间的调节关系，将HGC-27胃癌细胞株分为3组：空白对照、miR-15a（转染miR-15a模拟物）和miR-15a NC（转染模拟物阴性对照），检测各组miR-15a和Bmi-1的表达情况。通过生物信息学网站预测PVT1 与miR-15a以及miR-15a与Bmi-1的潜在结合位点。采用双荧光素酶报告基因技术验证PVT1 与miR-15a以及miR-15a和Bmi-1之间的靶向调节关系。在前述基础上，逆向验证PVT1、miR-15a和Bmi-1三者之间的调控关系。结果抑制PVT1、Bmi-1或者过表达miR-15a后，HGC-27胃癌细胞的OD490值以及增殖率在0 h后的不同时间点均出现显著降低（P&lt; 0.01）；抑制PVT1后，Bmi-1的表达出现降低，而miR-15a表达增高（P&lt; 0.01）；转染miR-15a后，miR-15a表达升高，而Bmi-1表达出现降低（P&lt; 0.01）。与空白对照和miR-15a模拟物阴性对照组相比，PVT1以及Bmi-1野生型报告基因的萤光素酶活性在miR-15a模拟物组呈现显著降低，两者分别下降约56%和32%左右（P&lt; 0.01）。与空白对照组和si-PVT1 NC组相比，si-PVT1组PVT1和Bmi-1表达明显下降，miR-15a表达升高，在si-PVT1组加入miR-15a inhibitor之后，miR-15a表达下降，PVT1 和Bmi-1的表达降低均出现了逆转；而si-PVT1组加入miR-15a后，miR-15a表达升高，在si-PVT1组加入miR-15a之后，miR-15a表达升高，PVT1 和Bmi-1的表达出现进一步下降。结论LncRNA-PVT1能够通过靶向抑制miR-15a上调Bmi-1（lncRNA-PVT1/miR-15a/Bmi-1通路），进而促进胃癌细胞的体外增殖

刚度变化下直升机行星齿轮-转子系统非线性动力学

建立了行星齿轮-转子系统的非线性动力学模型，系统模型将内啮合刚度嵌入齿圈刚度进行建模，考虑了转子扭转效应、齿侧间隙、时变啮合刚度和综合传动误差等因素。采用分岔图、最大李雅普诺夫指数（LLE）、庞加莱截面图和相图来分析响应特征。研究齿轮与转子间扭转振动位移响应，分析了旋翼轴与传动轴扭转刚度比变化影响规律。研究发现，系统具有非线性动力学特性，通过准周期分岔和倍周期分岔进入混沌运动，获得了系统避免失稳的刚度比阈值区间。研究为直升机主减速器行星齿轮-转子系统的动力学设计和扭转振动控制提供了参考

A highly selective probe for human cytochrome P450 3A4: isoform selectivity kinetic characterization and its applications

A highly selective probe for human cytochrome P450 3A4: isoform selectivity kinetic characterization and its application

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors