组织外植块对培养的鸡胚背根节神经突起生长的影响

为了解神经元的发育和周围组织的关系,本文分别用:(1) 10天鸡胚背根节与10天鸡胚心脏、皮肤、角膜、骨骼肌、肠、大脑、脊髓外植块联合培养;(2) 不同时期的鸡角膜与不同胚龄的鸡胚背根节联合培养;(3) 10天鸡胚背根节与雏鸡角膜内、外层联合培养。用于联合培养的背根节和组织外植块均按Maximow双盖片法种植在涂有鼠尾胶原的盖玻片上,两者相距1.5mm。外植块大小约0.5×1×1mm~3。培养48小时后取出固定,用改良的Bodian蛋白银法浸镀染色,在低倍镜下对神经突起进行半定量计数。 实验结果表明鸡胚心脏,皮肤和角膜外植块对背根节神经突起生长具较强的促进作用且对生长方向有明显诱导作用;骨骼肌、肠和大脑对神经突起生长也有不同程度促进作用,但脊髓却无明显作用。14、16、18天鸡胚角膜对8、10、12、14天鸡胚背根节神经突起生长有明显促进作用;12、14天鸡胚背根节在各时期角膜作用下神经突起生长都较丰富。含上皮层的雏鸡角膜外植块促进背根节神经突起生长的作用比含内皮层的角膜外植块要强

骨髓间充质干细胞向肌管状结构分化的动态

【目的】探讨5-氮胞苷体外诱导骨髓间充质干细胞（MSCs）向心肌细胞分化的最佳条件和体外分化的过程。【方法】体外培养Sprague-Dawley（SD）大鼠的MSCs，传代至P3、P6或P12；用5-氮胞苷诱导，比较不同诱导浓度组、不同诱导时间组和不同体重动物组MSCs的分化率，观察诱导后细胞分化过程中形态学的变化，并且用cardiactroponinⅠ、desmin和α-sarcomeric actin抗体鉴定分化的心肌样细胞。【结果】P12代较P3或P6代骨髓MSCs易向心肌样细胞分化并融合成肌管样结构。经10μmol／L的5-氮胞苷诱导24h后细胞分化率为（27±2．5）％，20μmol／L的5-氮胞苷诱导24h后细胞分化率为（17±2．2）%，其它诱导浓度和诱导时间均不能诱导细胞分化；50g（幼年鼠）体重组细胞分化率为（27±2．8）％，150g（成年鼠）体重组细胞分化率为（15±2．9）％，各组的差异有统计学意义。【结论】5-氮胞苷诱导MSCs向心肌样细胞分化并融合成肌管样结构，年幼的SD大鼠MSCs易向心肌样细胞分化

褪黑激素对新生大鼠神经干细胞向神经元样细胞分化的影响

【目的】探讨褪黑激素对体外培养新生大鼠神经干细胞分化的影响。【方法】从新生SD 大鼠室管膜下区分离依 赖碱性成纤维细胞生长因子(bFGF)和表皮细胞生长因子(EGF)生存的神经干细胞进行培养, 原代及子代细胞鉴定后用于实 验。实验细胞均在无生长因子而含10 mL/ L 胎牛血清条件下培养, 经褪黑激素或Luzindole 作用1 周后做免疫组织化学染色, 比较Map2 阳性细胞出现率。【结果】①依赖bFGF 和EGF 生长的神经干细胞体外呈集落样生长, 表达抗原蛋白巢蛋白 (Nestin), 无生长因子培养基中可分化形成胶质原纤维酸性蛋白(GFAP)、S100 蛋白、微管相关蛋白(Map2)阳性细胞。②褪黑 激素能够提高Map2 阳性细胞生成率(23.45 %, 21.82 %)(P <0.01)。③褪黑激素膜受体竞争性阻断剂Luzindole 可阻断高 浓度(100 μmol/ L)褪黑激素促神经干细胞分化作用, 但不能抑制低浓度褪黑激素(10 nmol/ L)的作用。【结论】褪黑激素能促 进神经干细胞向神经元样细胞分化, 不同浓度褪黑激素可能存在不同的作用机制

他莫昔芬诱导C6胶质瘤细胞凋亡及其作用机制

【目的】探讨他莫昔芬（TAM）对C6胶质瘤细胞凋亡的影响及其可能的作用机制。【方法】①TAM经不 同浓度、不同时间处理C6胶质瘤细胞后，用台盼蓝染色法检测细胞死亡现象，DAPI组化染色观察凋亡细胞核形 态，DNA阶梯法和FACS检测细胞凋亡，Westernblot法分析PKCα磷酸化水平。②PKCα特异性抑制剂Go6976与 TAM联合处理C6胶质瘤细胞后，DNA阶梯法和FACS检测C6胶质瘤细胞凋亡。【结果】①TAM能诱导C6胶质瘤 细胞死亡，且与TAM浓度、TAM处理时间呈正相关；TAM组可见典型的细胞凋亡的形态学变化（如核固缩）和明显 的DNA梯度条带； C6胶质瘤细胞凋亡率和PKCα磷酸化水平具有TAM浓度依赖性和时间依赖性。②Go6976与 TAM联合处理C6胶质瘤细胞后，可进一步促进TAM诱导的C6胶质瘤细胞凋亡。【结论】TAM能诱导C6胶质瘤细 胞凋亡，且PKCα参与介导TAM诱导的C6胶质瘤细胞凋亡。该研究可为临床神经胶质瘤的治疗提供实验依据

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^

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