科创中国

目的 观察红景天对模拟不同海拔高度缺氧的大鼠视网膜组织形态以及缺氧诱导因子(HIF)表达的影响.方法 成年雌性Sprague Dawley大鼠48只随机分为干预组和对照组,每组24只.干预组大鼠按10 ml/lg的剂量腹腔注射大珠红景天注射液,对照组大鼠按相同剂量注射生理盐水.注射后1h,两组随机选取6只大鼠分别饲养于氧分压为17.6、14.7、11.3、7.4 kPa的高原环境模拟实验舱,室内模拟的海拔高度分别为1500、3000、5000、8000 m.饲养后6h摘除大鼠眼球作石蜡切片.采用苏木精伊红染色观察大鼠视网膜病理形态的改变,免疫组织化学染色观察大鼠视网膜中HIF-1α、p53的表达.分析HIF-1α与p53表达的相关性.结果 对照组大鼠视网膜各层组织水肿疏松,视网膜厚度增加,层次排列紊乱,神经节细胞肿胀变性,可见核固缩溶解及细胞数量减少;随着模拟的海拔高度增加,其视网膜病理形态改变越明显.干预组大鼠视网膜组织形态改变特点同对照组,改变程度轻于对照组.对照组大鼠视网膜中HIF-1α、p53表达主要位于神经节细胞层和内核层;随着模拟的海拔高度增加,HIF-1α、p53表达也增加.与对照组比较,干预组大鼠视网膜中HIF-1α表达增加,p53表达降低,差异均有统计学意义(P<0.05).相关性分析结果显示,HIF-1α与p53的表达呈正相关(r=0.984 6,P<0.05).结论 红景天能改善模拟高海拔缺氧所致的大鼠视网膜组织病理损害,其作用机制可能与上调HIF-1α表达、下调p53表达有关.

在户外运动时,驴友们面临的首要问题就是天气的变化,尤其是到一些高海拔地区,很可能在一天内经历风、雨、雹、雪4种天气的变化,因此对衣着的要求格外高,防风、透气、保暖等功能,一个都不能少.但是,在选购户外运动服装时,除了要关注其功能外,更重要的是实用.

香格里拉是一个充满神秘与传奇的地方,这里蕴藏着世界上最为丰富的植物资源.香格里拉境内的地势北高南低,地形呈纵深切割之势,海拔高差极为悬殊,最高的梅里雪山海拔可达6740米,而最低谷的海拔却仅1486米,

随着气候变暖及种植业结构的调整,青海省东部冬小麦的种植不断向高海拔地区扩展,为勘定小麦条锈菌在青海冬麦区的越冬情况,2008-2012年以青海省民和、乐都、尖扎、化隆、循化、贵德等地为试点,按照海拔梯度设立观测圃进行定点越冬观察.结果表明,一般年份小麦条锈菌在青海省东部地区海拔1 777~2 233 m均可越冬.不同年份间条锈菌能否越冬及越冬率的高低差异很大,当1月份平均气温在-8.0℃以下时,条锈菌在所有区域均不能越冬;当1月份平均气温在-5.0℃以上时,条锈菌能够越冬.此外,1-3月的降水量对小麦条锈菌的越冬也有影响.不同海拔地区条锈菌的越冬率存在一定差异,总趋势是海拔越低病菌越冬率越高,海拔越高病菌越冬率越低.

In order to compare the two species' flight performance over the exposed and windy Falsterbo Peninsula, where thermal conditions seldomly are very favorable, we used tracking radar to study flight parameters of sparrowhawks Accipiter ni- sus and common buzzards Buteo buteo during autumn migration. The results showed a clear difference between sparrowhawks and common buzzards in their flight altitudes and speeds, and in the wind conditions they encountered. Common buzzards had higher flight altitudes and were more selective of wind. Flight altitude was negatively related to the wind speed, which was most pronounced for common buzzards. Sparrowhawks had higher mean air- and cross-country speeds than common buzzards. Air- speed was negatively related, whereas ground and cross-country speeds were positively related to the tailwind component for both raptors. The differences between sparrowhawks and buzzards could to a large degree be explained by a larger dependence on thermal soaring among the common buzzards; a strategy associated with selectivity for favourable thermal and wind conditions during migratory flight. An additional important explanation for the interspecific differences was the habit of the sparrowhawks to combine migratory flight with hunting for prey, which makes it prone to fly at lower altitudes and use flapping flight to a much larger degree than common buzzards which do not forage during their migratory passage of the Falsterbo Peninsula [Current Zoo- logy 60(5): 670-679, 2014].