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1.
扁窦形短指软珊瑚Sinularia depressa的甾醇和甾醇甙   总被引:1,自引:2,他引:1  
首次报道采自海南三亚附近海域的扁窦形短指软珊瑚Sinularia depressa Tixier-Durivault的化学成分,从中分离鉴定出5种甾醇化合物经波谱分析确定它们分别为豆甾—5—烯-3β—D—吡喃葡萄糖甙,(24S)—麦角甾-5—烯—3β,7α—二醇,柳珊瑚甾醇,此外还有胸腺嘧啶和鲨肝醇。  相似文献   

2.
从采自海南三亚附近海域的短指软珊瑚Sinularia papillosa中首次分离得共轭甾酮,经波谱分析,鉴定它们分别为(5α)-孕甾-1,20-二烯-3-酮和孕甾-1,4,20-三烯-3-酮.  相似文献   

3.
从南中国海采集的小棒短指软珊瑚Sinularia microclavata Tix-Dur中首次分离得2个氧化甾醇. 通过各种近代波谱分析方法,鉴定出它们分别为孕甾-5-烯-3-醇-20-酮(pregnenolone)(1)和9,11-开环-24-亚甲基-5α-胆甾-7-烯-3β,6α,11-三羟基-9酮(2).1和2均有较强的细胞毒活性.  相似文献   

4.
南海短指软珊瑚Sinularia sp.次生代谢物质研究   总被引:1,自引:0,他引:1  
从海南三亚附近海域采集的一种短指软珊瑚Sinularia sp.中分离到5种次生代谢产物,通过物理常数对照和波谱分析鉴定,它们分别为柳珊瑚甾醇、麦角甾-24(28)-烯-3β,5α,6β-三醇。  相似文献   

5.
格氏短指软珊瑚的次生代谢产物研究   总被引:4,自引:0,他引:4  
从海南三亚附近海域采集的格氏短指软珊瑚SinulariagrayiTix _Dur 中分离得 7种次生代谢产物。通过波谱分析鉴定它们的结构为 :(2 4s)_2 4_甲基胆甾_3β ,5α ,6 β ,2 5_四醇_2 5_单乙酸酯 ,(2 4s)_2 4_甲基胆甾_4_烯_3β ,6 β_二醇 ,柳珊瑚甾醇 ,麦角甾_5_烯_3β_醇 ,麦角甾_5 ,2 4 (2 8)_二烯_3β_醇 ,Δ4 ,5(E) ,Δ8,9(E)鞘胺醇_正十六碳酰胺 ,胸腺嘧啶。  相似文献   

6.
从中国南海海域采集的乌绿草虫软珊瑚Cespitularia cocerulea May中分离到3个化合物。经波谱分析,确定它们的化学结构为:(2S,3R,2 R,4E,8E)-N-(2-羟基-正二十碳酰基)-9-甲基-4,8-二烯-1,3-二羟基-2-氨基-十九烷(1),Δ4,5(E),Δ8,9(E)-鞘胺醇-正十六碳酰胺(2)和麦角甾-3β,5α,6β-三醇(3),其中1为新化合物。  相似文献   

7.
利用柱层析和制备薄层色谱技术研究扁缩滨珊瑚(Porites compressa Dana)的化学成分,从中分离纯化得到2个化合物:a-十八碳烷醇甘油醚(鲨肝酵)(I)、N-1-羟基甲基-2-羟基-(E,E)-3,7-十七碳二烯基十六酸酰胺(Ⅱ);同时经GC-MS鉴定6个甾醇:麦角甾烷酵、豆甾-22-烯-3β-醇、麦角甾-5-烯--3β酵、胆甾-5-烯-3β-醇、麦角甾-5,22-二烯-3β-醇和豆甾-5,22-二烯-3β-醇.  相似文献   

8.
从中国小棒短指软珊瑚(Sinularia microclavata)的天然代谢产物,分离出10个结晶化合物。本文对3β、5α、6β-三羟基,24-亚甲基胆甾烷(24-methylene cholestane-3β、5α,6β-triol),24-亚甲基胆甾醇(24-methylenecholesterol)和柳珊瑚甾醇(gorgosterol)3个化合物进行了波谱和化学分析,并推导了它们的结构。  相似文献   

9.
从中国南海软珊瑚Sarcophyton tortuosum中分离到一种新的多羟基甾醇——扭曲肉芝甾醇A(Sartortaosterol A),通过化学反应和四谱法推定其化学结构为24ξ-甲基-5α-胆甾烷-3α,6β,9α-,25-四醇-25-乙酸酯.  相似文献   

10.
首次对优美叶枝豆荚软珊瑚Lobophytum delectum的次生代谢产物进行了研究并分离鉴定出3个多羟基甾醇和1个神经酰胺。通过波谱分析、化学降解及物理常数对照等方法鉴定出它们的化学结构分别为:(24S)-麦角甾-1β,3β,5α,6β-四醇(1)、(24S)-麦角甾-3β,5α,6β,25-四醇-25-单乙酸酯(2)、(24S)-麦角甾-5-烯-3β,25-二醇(3)和N-正十六碳酰基-正十八碳-4(E),8(E)-二烯鞘胺醇(4),首次发现(1)对MgC-803(人胃癌细胞)和Cne-1(人鼻咽癌细胞)有强抑制活性,IC50值分别为1.48和1.12μg/mL。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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