高原环境因素与自由基反应

高原环境是一个特殊的生态环境系统,其复杂多变的自然地理条件使移居和新进高原环境的人群或生物出现高原反应或发生“高原(山)病”。大气压低、氧分压低、太阳辐射强所导致的氧化应激反应是高原反应或高原病的主要原因之一。本文从高原气候因素与自由基反应,不同海拔高度对不同民族人群自由基反应的影响,相同海拔高度不同人群的自由基反应,海拔高度与机体抗氧化营养物质变化的关系,不同海拔高度紫外线强度与自由基反应及高原环境地球化学异常与自由基反应等6个方面,论述了高原环境因素与不同人群自由基反应的关系,不仅对探讨环境应激反应所产生的自由基反应与世居高原地区人群起源和进化有重要意义,而且对研究移居人群高原反应和高原病的预防、治疗及经济、国防建设具有现实应用价值

燃煤污染型氟中毒流行特点及氟安全阈值研究

目的　查明我国燃煤污染型氟中毒的环境流行特征 ,确定煤炭氟的安全阈值 ,为氟的环境风险评价提供科学依据。方法　现场调查和资料分析相结合。结果　燃煤污染型氟中毒的流行与地球化学环境密切相关 ,但高氟煤炭的存在是其流行的决定因素。病区居民氟斑牙患病率与煤炭氟含量之间存在线性函数关系 (r =0 .943 2 ,P <0 .0 1) ,去掉 5 %的氟斑牙诊断误差和模糊判定因素等 ,煤炭氟的安全阈值为 2 5 0 mg/kg。结论　煤炭氟含量应作为煤炭资源开采与否的一个指标。对于燃煤污染型氟中毒病人应早发现、早诊断、早治疗 ,其防治应把治病与治穷结合起

胎儿肝脏21种化学元素含量的动态变化规律及其营养生理学意义

为探索胎儿肝脏化学元素的含量及其动态变化规律和营养生理学意义 ,通过分析 4～ 10月龄胎儿肝脏 2 1个化学元素的含量并与成人比较 ,将 2 1种元素的月平均值与胎儿月龄进行相关分析、分类。结果表明 ,胎儿生长发育过程中肝脏化学元素的含量呈不均匀的非稳定状态且随月龄而变化 ,其变化趋势可区分为与月龄增长呈显著正相关、显著负相关和相关不显著 3类。呈显著正相关元素的含量在胚胎 -胎儿 -新生儿、婴幼儿期由低向高变化 ,表明母体这些元素除供胎儿整体发育所需外 ,仍可使胎儿肝脏中的这类元素含量有所增加 ;呈显著负相关的元素由高向低变化 ,使单位组织质量中元素的含量很快减少 ,增加了组织对这类元素缺乏的敏感性 ;而相关不显著的元素可能不存在营养生理问

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