多囊卵巢综合征(Polycystic ovary syndrome,PCOS)是一组生殖内分泌代谢紊乱的综合征,临床以稀发排卵、高雄激素体征、胰岛素抵抗为主要特征,其中育龄期发病率高,对女性生育力造成严重不良影响。PCOS的发生发展涉及多种信号通路,腺苷酸...多囊卵巢综合征(Polycystic ovary syndrome,PCOS)是一组生殖内分泌代谢紊乱的综合征,临床以稀发排卵、高雄激素体征、胰岛素抵抗为主要特征,其中育龄期发病率高,对女性生育力造成严重不良影响。PCOS的发生发展涉及多种信号通路,腺苷酸活化蛋白激酶(AMP-activated protein kinase,AMPK)及哺乳动物雷帕霉素靶蛋白(Mammalian target of rapamycin,mTOR)作为细胞能量感受器是其中两个关键靶点。二者在PCOS各个发病部位包括下丘脑-垂体-卵巢轴、子宫内膜、脂肪与骨骼肌中发挥重要的调节作用,通过影响细胞自噬、氧化应激、炎症、线粒体功能、葡萄糖摄取等,促进卵泡的发育和成熟,改善胰岛素抵抗。近年来,中医药因其成分多样、靶点众多等优势广泛应用于临床,研究人员已对PCOS的发病以及中药治疗及改善PCOS的机制进行了大量研究,结果提示AMPK与mTOR相关通路在其中发挥关键作用。通过总结中药干预AMPK与mTOR及其相关通路治疗PCOS的研究结果,为临床治疗及基础研究提供参考。展开更多
A wide-band polarization-insensitive and wide-angle metamaterial absorber based on loaded magnetic resonators is presented.The unit cell of this absorber consists of a magnetic resonator loaded with lumped resistances...A wide-band polarization-insensitive and wide-angle metamaterial absorber based on loaded magnetic resonators is presented.The unit cell of this absorber consists of a magnetic resonator loaded with lumped resistances,a dielectric substrate and a back metal film.Theoretical and simulated results show that this absorber has a wide-band strong absorption for the incident wave from 3.87 GHz to 21.09 GHz.Simulated absorbance values under loading and unloading conditions indicate that electrocircuit's resonances are more stable than electromagnetic resonances and thus can be used to realize wide-band absorption.Simulated absorbance values under different polarization angles and different angles of incidence indicate that this absorber is polarization-insensitive and wide-angle.It may have potential applications in military fields.展开更多
China is facing severe problem of water scarcity.Agricultural sector,the main consumer of water resource,has remarkably changed its institutions on water resource deployment,due to heavy environmental pressure.As a ne...China is facing severe problem of water scarcity.Agricultural sector,the main consumer of water resource,has remarkably changed its institutions on water resource deployment,due to heavy environmental pressure.As a new and spontaneous institution,groundwater market has developed rapidly in northern China,and has impacts on waterusing behaviors and benefits of farmers.Using household survey data from Hebei and Henan in 2007,this paper attempts to pin down the development and operating of groundwater market in rural China.We focus on the monopoly and competition in the market.Empirical analysis reveals that Chinese farmers are trying to make rational decision when they compete with others in groundwater market.In general,monopoly is not fierce in Chinese rural groundwater market,with great variations among different villages and even different tubewells within one village.Tubewell costs,regulation and the density of tubewells are the main determinants that affect monopoly level of groundwater market.To make water market benefit more and more farmers of low income,corresponding policies are needed to modify its development in the future.展开更多
文摘多囊卵巢综合征(Polycystic ovary syndrome,PCOS)是一组生殖内分泌代谢紊乱的综合征,临床以稀发排卵、高雄激素体征、胰岛素抵抗为主要特征,其中育龄期发病率高,对女性生育力造成严重不良影响。PCOS的发生发展涉及多种信号通路,腺苷酸活化蛋白激酶(AMP-activated protein kinase,AMPK)及哺乳动物雷帕霉素靶蛋白(Mammalian target of rapamycin,mTOR)作为细胞能量感受器是其中两个关键靶点。二者在PCOS各个发病部位包括下丘脑-垂体-卵巢轴、子宫内膜、脂肪与骨骼肌中发挥重要的调节作用,通过影响细胞自噬、氧化应激、炎症、线粒体功能、葡萄糖摄取等,促进卵泡的发育和成熟,改善胰岛素抵抗。近年来,中医药因其成分多样、靶点众多等优势广泛应用于临床,研究人员已对PCOS的发病以及中药治疗及改善PCOS的机制进行了大量研究,结果提示AMPK与mTOR相关通路在其中发挥关键作用。通过总结中药干预AMPK与mTOR及其相关通路治疗PCOS的研究结果,为临床治疗及基础研究提供参考。
基金by the National Natural Science Foundation of China under Grant Nos 50632030,60871027,60901029 and 61071058the National Basic Research Program of China under Grant No 2009CB623306the National Natural Science Foundation of Shaanxi Province under Grant No SJ08F01.
文摘A wide-band polarization-insensitive and wide-angle metamaterial absorber based on loaded magnetic resonators is presented.The unit cell of this absorber consists of a magnetic resonator loaded with lumped resistances,a dielectric substrate and a back metal film.Theoretical and simulated results show that this absorber has a wide-band strong absorption for the incident wave from 3.87 GHz to 21.09 GHz.Simulated absorbance values under loading and unloading conditions indicate that electrocircuit's resonances are more stable than electromagnetic resonances and thus can be used to realize wide-band absorption.Simulated absorbance values under different polarization angles and different angles of incidence indicate that this absorber is polarization-insensitive and wide-angle.It may have potential applications in military fields.
基金supported by International Water Management Institute-Groundwater Governance in Asia Program(Grant No.PN-42)
文摘China is facing severe problem of water scarcity.Agricultural sector,the main consumer of water resource,has remarkably changed its institutions on water resource deployment,due to heavy environmental pressure.As a new and spontaneous institution,groundwater market has developed rapidly in northern China,and has impacts on waterusing behaviors and benefits of farmers.Using household survey data from Hebei and Henan in 2007,this paper attempts to pin down the development and operating of groundwater market in rural China.We focus on the monopoly and competition in the market.Empirical analysis reveals that Chinese farmers are trying to make rational decision when they compete with others in groundwater market.In general,monopoly is not fierce in Chinese rural groundwater market,with great variations among different villages and even different tubewells within one village.Tubewell costs,regulation and the density of tubewells are the main determinants that affect monopoly level of groundwater market.To make water market benefit more and more farmers of low income,corresponding policies are needed to modify its development in the future.
