紫云英苷抑制APP/PS1小鼠大脑皮质神经元凋亡

目的探讨紫云英苷 （AST）对APP/PS1转基因小鼠大脑皮质神经元凋亡的影响。方法将18只6月龄雄性APP/PS1转基因小鼠随机分为APP/PS1、APP/PS1+40 mg/kg AST、APP/PS1+20 mg/kg DNP （Donepezil， DNP）三组，每组各6只动物。同时另选6只同月龄C57BL/6雄性小鼠作为正常对照组 （Control）。腹腔注射给药AST，每日一次，连续给药一个月后，Tunel染色法检测APP/PS1小鼠大脑皮质内神经元凋亡情况；免疫荧光染色法检测APP/PS1小鼠大脑皮质内神经元凋亡相关蛋白Bax、Bcl-2、Caspase9、Cleaved-Caspase3表达情况；Western blot法检测APP/PS1小鼠大脑皮质内Bax、Bcl-2、Caspase9及Caspase3表达水平的变化。结果Tunel染色结果显示，40 mg/kg AST及20 mg/kg DNP均可减少APP/PS1小鼠大脑皮质内神经元凋亡，其中AST抑制效果尤为明显。免疫荧光染色结果表明，40 mg/kg AST及20 mg/kg DNP均抑制APP/PS1小鼠大脑皮质内神经元中Bax、Caspase9及Cleaved-Caspase3的表达，增加Bcl-2的表达。Western blot 结果进一步证实，40 mg/kg AST及20 mg/kg DNP均可下调APP/PS1小鼠大脑皮质内神经元Bax （P < 0.05， P < 0.05）、Caspase9 （P < 0.005， P < 0.05）及Caspase3 （P<0.000 1， P<0.000 1），上调Bcl-2 （P < 0.05， P < 0.05）。结论AST能够抑制APP/PS1小鼠大脑皮质神经元凋亡

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

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