Anti-Osteoporosis Effects Induced by Retinoic Acid in Mice of Hexane Extract from Raw and Processed Polygonum multiflorum

研究生、制首乌正己烷提取物对维甲酸致小鼠骨质疏松的防治作用,并探讨其主要作用机制。采用维甲酸(105 mg·kg~(-1))致小鼠骨质疏松模型,生首乌正己烷提取物高、低剂量组48、24 mg·kg~(-1),清蒸制首乌正己烷提取物高、低剂量组48、24 mg·kg~(-1),黑豆制何首乌正己烷提取物高、低剂量组48、24 mg·kg~(-1),灌胃给药,2周后以比色法测定血清钙、磷含量和碱性磷酸酶(ALP)、抗酒石酸酸性磷酸酶(TRAP)活性,竞争放射免疫法测定血清中骨钙素(BGP)和雌二醇(E2)含量,取股骨进行骨组织形态学观察。结果表明:维甲酸可引起高转换型骨质疏松,与模型组比较,生、制首乌各剂量组可显著升高s-E2的水平(P <0.05),降低s-ALP、s-TRAP和s-BGP的水平(P<0.05,P<0.01);生、制首乌各组与模型组比较,骨组织形态均有不同程度的改善,骨小梁数明显增加。从以上结果可知,生、制首乌正己烷提取物对维甲酸致小鼠骨质疏松有明显的治疗作用,其机制可能与减缓雌激素水平降低,抑制骨高转换有关

大功率分动器润滑散热系统的设计与试验研究

大功率分动器作为某多轴超重型底盘传动系统的关键部件,具有传递转矩大、转速高、环境温差大等特点,单纯依靠飞溅润滑和自然风冷散热已无法满足多轴超重型底盘高机动性、高越野性和极限环境温度的使用需求,需采用强制润滑系统对分动器内部各产热点尤其是轴承位置进行润滑。因此,首先建立了传动部件各产热点的功率热能模型,通过热平衡条件估计各润滑点和总体的流量需求,然后建立液压仿真分析模型,设计匹配润滑系统管路;同时,针对动力传动系统功率大,自然风冷散热无法满足分动器热平衡要求的问题,通过计算分动器的表面风速、散热表面积评估分动器箱体自身的散热能力,并根据散热量需求匹配外置的风冷散热器和风扇。最后,通过台架和跑车试验,验证了所设计的大功率分动器强制润滑散热系统能够满足某多轴超重型底盘的各项使用要求

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