目的综述B类I型清道夫受体(scavenger receptor class B type I,SR-BI)基因表达上调剂的研究进展。方法查阅近年来国内外相关文献29篇,对其进行归纳总结和分析。结果 SR-BI是高密度脂蛋白(high density lipoprotein,HDL)受体,能选择性...目的综述B类I型清道夫受体(scavenger receptor class B type I,SR-BI)基因表达上调剂的研究进展。方法查阅近年来国内外相关文献29篇,对其进行归纳总结和分析。结果 SR-BI是高密度脂蛋白(high density lipoprotein,HDL)受体,能选择性介导胆固醇和HDL颗粒中胆固醇酯的吸收,在HDL的代谢中起重要作用。提高SR-BI基因表达,可促进胆固醇外流,降低血浆胆固醇水平,因此SR-BI基因表达上调剂有望成为新型抗动脉粥样硬化药物。许多报道的天然或合成小分子化合物具有SR-BI基因表达上调活性,有进一步研究价值。结论已报道的化合物虽然活性值不高,直接作为SR-BI基因表达上调剂候选药物应用较为困难,但以其为先导化合物,进行结构优化,对发现新的结构新颖、活性显著的SR-BI基因表达上调剂有重要意义。展开更多
Barium metaborate (BaB 2O 4) exists in two forms the high temperature for m α phase and the low temperature form β phase,with the phase transition poi nt at around 925℃.The low temperature phase (β BBO) is an exce...Barium metaborate (BaB 2O 4) exists in two forms the high temperature for m α phase and the low temperature form β phase,with the phase transition poi nt at around 925℃.The low temperature phase (β BBO) is an excellent NLO cryst al for UV region,while the high temperature one (α BBO) is known as a good bir efringent material.α BBO crystal possesses better transparency in the ultravio let region compared with commonly used YVO 4 and CaCO 3 crystals.However,due t o phase transition problem,it is difficult to grow single α BBO crystals by D CZ method,which restricts its wider application.α BBO crystal usually cracks upon cooling resulted from phase transition to β phase.Therefore,it is difficult to grow β BBO single crystals directly from pure BaB 2O 4 mel t;however,to grow single crystals of α BBO is not easy,either. Our recent experiments showed that one could avoid cracking of α BBO cryst als by Sr 2+ doping.This minute amount of Sr 2+ plays the role of structure stabilizer,which inhibits structural reconstruction. In this way,Sr 2+ d op ed BBO single crystals do not subject to phase transition from 925℃ down to roo m temperature. We have mow successfully grown out α BBO single crystals 30mm in diameter by D CZ method from Sr x Ba 1- x BO 4 melt with Sr concentration 0.3 0 .5%.The ratation rate is 10 15r/min,pulling speed is 1 2mm/h.Preliminary tests revealed that its structure and physic chemical properties were almost identic al to those grown from pure melts.These Sr 2+ doped α BBO crystals are no w being widely used in optical isolators.展开更多
重庆中坝遗址地层Rb、Sr、Hg及TOC研究表明:Rb、Sr和Rb/Sr值较好地反映了约4250 a B.P.以来气候变化过程,主要干冷期可与敦德冰川δ18O曲线谷值、湖光岩沉积物磁化率和Ti曲线峰值、以及大气14C浓度峰值和太阳活动水平较长期变化的低谷对...重庆中坝遗址地层Rb、Sr、Hg及TOC研究表明:Rb、Sr和Rb/Sr值较好地反映了约4250 a B.P.以来气候变化过程,主要干冷期可与敦德冰川δ18O曲线谷值、湖光岩沉积物磁化率和Ti曲线峰值、以及大气14C浓度峰值和太阳活动水平较长期变化的低谷对比,反映出地层中Rb、Sr不易受人类活动干扰的特性。结合考古遗存对比还发现,Hg、P、Ca、Mg和TOC记录了该遗址约4250 a B.P.以来人类活动的三个不同演变阶段。进一步研究认为,盐业遗址的衰落可能与洪水事件。展开更多
文摘目的综述B类I型清道夫受体(scavenger receptor class B type I,SR-BI)基因表达上调剂的研究进展。方法查阅近年来国内外相关文献29篇,对其进行归纳总结和分析。结果 SR-BI是高密度脂蛋白(high density lipoprotein,HDL)受体,能选择性介导胆固醇和HDL颗粒中胆固醇酯的吸收,在HDL的代谢中起重要作用。提高SR-BI基因表达,可促进胆固醇外流,降低血浆胆固醇水平,因此SR-BI基因表达上调剂有望成为新型抗动脉粥样硬化药物。许多报道的天然或合成小分子化合物具有SR-BI基因表达上调活性,有进一步研究价值。结论已报道的化合物虽然活性值不高,直接作为SR-BI基因表达上调剂候选药物应用较为困难,但以其为先导化合物,进行结构优化,对发现新的结构新颖、活性显著的SR-BI基因表达上调剂有重要意义。
文摘Barium metaborate (BaB 2O 4) exists in two forms the high temperature for m α phase and the low temperature form β phase,with the phase transition poi nt at around 925℃.The low temperature phase (β BBO) is an excellent NLO cryst al for UV region,while the high temperature one (α BBO) is known as a good bir efringent material.α BBO crystal possesses better transparency in the ultravio let region compared with commonly used YVO 4 and CaCO 3 crystals.However,due t o phase transition problem,it is difficult to grow single α BBO crystals by D CZ method,which restricts its wider application.α BBO crystal usually cracks upon cooling resulted from phase transition to β phase.Therefore,it is difficult to grow β BBO single crystals directly from pure BaB 2O 4 mel t;however,to grow single crystals of α BBO is not easy,either. Our recent experiments showed that one could avoid cracking of α BBO cryst als by Sr 2+ doping.This minute amount of Sr 2+ plays the role of structure stabilizer,which inhibits structural reconstruction. In this way,Sr 2+ d op ed BBO single crystals do not subject to phase transition from 925℃ down to roo m temperature. We have mow successfully grown out α BBO single crystals 30mm in diameter by D CZ method from Sr x Ba 1- x BO 4 melt with Sr concentration 0.3 0 .5%.The ratation rate is 10 15r/min,pulling speed is 1 2mm/h.Preliminary tests revealed that its structure and physic chemical properties were almost identic al to those grown from pure melts.These Sr 2+ doped α BBO crystals are no w being widely used in optical isolators.
基金supported by the Base to Clinical and Scientific Research Cooperation fund of Capital Medical University(15JL67)the High-tech personnel training grant from Beijing Health System(2015-3-104)the Beijing municipal education commission on science and technology plan projects(KM201610025021)
文摘重庆中坝遗址地层Rb、Sr、Hg及TOC研究表明:Rb、Sr和Rb/Sr值较好地反映了约4250 a B.P.以来气候变化过程,主要干冷期可与敦德冰川δ18O曲线谷值、湖光岩沉积物磁化率和Ti曲线峰值、以及大气14C浓度峰值和太阳活动水平较长期变化的低谷对比,反映出地层中Rb、Sr不易受人类活动干扰的特性。结合考古遗存对比还发现,Hg、P、Ca、Mg和TOC记录了该遗址约4250 a B.P.以来人类活动的三个不同演变阶段。进一步研究认为,盐业遗址的衰落可能与洪水事件。
