短柄五加中抑菌活性成分研究

利用抑菌活性追踪及各种色谱方法从短柄五加(Acanthopanax brachypus)的根茎中分离得到6个黄酮类化合物,通过理化性质和波谱数据鉴定化合物的结构分别为:藿香黄酮醇(1)、汉黄芩素(2)、山奈酚-7-O-β-D-葡萄糖苷(3)、牡荆苷(4)、金丝桃苷(5)及黄芩苷(6).除化合物5外,其余5个化合物均为首次从该植物中分离得到.采用体外抑菌活性试验法测定各提取物的抑菌活性.结果表明,短柄五加乙醇提取物中的乙酸乙酯组分,尤其是化合物1、2、4和5对供试菌种显示较强的抑菌活性.     

秦岭中草药黄芩中黄酮类化合物的分离及其α-葡萄糖苷酶抑制活性研究

目的分离鉴定秦岭中草药黄芩中的黄酮类物质并研究其对α-葡萄糖苷酶的抑制活性。方法植物原料用溶剂提取,常压硅胶柱色谱及制备液相色谱分离,高分辨质谱及核磁共振波谱分析确定化合物分子结构,PNPG法测定化合物的α-葡萄糖苷酶的抑制活性。结果分离鉴定了8种黄酮类化合物,分别是汉黄芩素(1)、黄芩素(2)、汉黄芩苷(3)、千层纸素A-7-O-葡萄糖酸苷(4)、白杨素-7-O-葡萄糖酸苷(5)、黄芩苷(6)、黄芩素-6-O-葡萄糖酸苷(7)和去甲汉黄芩素-8-O-葡萄糖酸苷(8),活性实验表明化合物1和7表现出较好的α-葡萄糖苷酶的抑制活性,其IC_(50)分别为0.13mmol/L和0.25mmol/L,稍强于阳性对照阿卡波糖(IC_(50):0.42mmol/L)。结论秦岭中草药黄芩中某些黄酮类物质能够有效抑制α-葡萄糖苷酶,具有与阿卡波糖相当的降糖作用。     

秦岭中草药黄芩中黄酮类化合物的分离

目的 分离鉴定秦岭中草药黄芩中的黄酮类物质并研究其对α-葡萄糖苷酶的抑制活性.方法 植物原料用溶剂提取,常压硅胶柱色谱及制备液相色谱分离,高分辨质谱及核磁共振波谱分析确定化合物分子结构,PNPG法测定化合物的α-葡萄糖苷酶的抑制活性.结果 分离鉴定了8种黄酮类化合物,分别是汉黄芩素(1)、黄芩素(2)、汉黄芩苷(3)、千层纸素A-7-O-葡萄糖酸苷(4)、白杨素-7-O-葡萄糖酸苷(5)、黄芩苷(6)、黄芩素-6-O-葡萄糖酸苷(7)和去甲汉黄芩素-8-O-葡萄糖酸苷(8),活性实验表明化合物1和7表现出较好的α-葡萄糖苷酶的抑制活性,其IC50分别为0.13 mmol/L和0.25 mmol/L,稍强于阳性对照阿卡波糖(IC50:0.42 mmol/L).结论 秦岭中草药黄芩中某些黄酮类物质能够有效抑制α-葡萄糖苷酶,具有与阿卡波糖相当的降糖作用.     

黄芩素和黄芩苷抗氧化活性与结构关系的密度泛函理论研究

采用密度泛函理论方法对黄芩素和黄芩苷分子进行构象扫描,获得2个化合物的最低能量构象并对其进行了全优化.从分子的几何结构、酚羟基解离能BDE、绝热电离势IP、HOMO和LUMO能级以及其能级差ΔE(LUMO-HOMO)等方面分析了2个化合物的抗氧化活性与结构的关系.结果表明,C6位的酚羟基为黄芩素和黄芩苷的最大反应活性位点.在非极性溶剂中,化合物抗氧化活性取决于分子中酚羟基的脱氢能力,黄芩苷的抗氧化活性大于黄芩素的抗氧化活性.在极性溶剂中,抗氧化活性取决于分子中单电子的电离势,黄芩苷的抗氧化活性大于黄芩素的抗氧化活性.     

山茱萸中生物活性物质的分离、鉴定及其神经保护作用

研究山茱萸乙醇提取物中生物活性成分的化学组成及其对神经的保护作用。采用正相常压硅胶、Sephadex LH-20凝胶、大孔吸附树脂、闪式低压正反相硅胶和氰基、反相高压液相等色谱方法对显示具有神经保护活性的组分进行分离纯化,根据核磁共振谱、质谱,同时结合已知文献数据对比鉴定化合物结构;再采用H_2O_2诱导的SH-SY5Y细胞氧化损伤模型对分离鉴定的化合物进行体外神经保护活性测定。结果表明,从山茱萸显示神经保护活性的组分中分离鉴定了9个化合物,分别为7-β-莫诺苷(1)、7-β-O-甲基莫诺苷(2)、7-α-0-甲基莫诺苷(3)、金吉苷(4)、cornolactones D(5)、pollenfuran A(6)、threo-2,3-bis (4-hydroxy-3-methoxyphenyl)-3-ethoxypropan-1-ol (7)、5-羟甲基糠醛(8)和3,4-二-羟基苯甲酸(9);其中化合物pollenfuran A(6)和threo-2,3-bis(4-hydroxy-3-methoxyphenyl)-3-ethoxypropan-1-ol(7)为首次从山茱萸属植物中分离得到,化合物cornolactones D(5)为首次从山茱萸中分离得到;化合物7-β-莫诺苷(1)、7-β-0-甲基莫诺苷(2)、7-α-0-甲基莫诺苷(3)具有神经保护活性。     

黄芩苷纯化方法的研究

黄芩苷是从中药黄芩中提取得到的一种黄酮类化合物,具有抑菌、抗病毒、抗炎、清热等多种药理活性,如何提高其得率和纯度一直是实际生产中存在的问题。本论文从黄芩中提取、纯化出了高纯度的黄芩苷,产率为5.14%,并通过薄层层析(TLC)的方法检验其纯度,核磁共振(13C NMR)的方法鉴定了黄芩苷的结构。     

黄芩苷酯类衍生物的合成

基于前药设计原理,设计合成了6个黄芩苷酯类衍生物.黄芩苷与甲烷磺酸甲酯、甲烷磺酸乙酯反应,得到目标化合物1和2.黄芩苷与乙酸酐反应,得到化合物3,3分别与甲烷磺酸甲酯、甲烷磺酸乙酯和甲烷磺酸异丙酯反应,得到目标化合物4、5和6.化合物结构均经ESI-MS和1H NMR确证.化合物4、5和6易溶于乙酸乙酯,具有较好的脂溶性.     

满天星中的黄酮类化合物及其抗氧化活性

 对石竹科花卉植物满天星(Gypsophila elegans)进行化学成分研究,通过波谱技术鉴定化合物结构,得到6 个黄酮苷化合物,分别为2″-O-α-L-阿拉伯糖异荭草苷(1)、芹黄素-6-C--7-O-β-D-吡喃葡萄糖苷(2)、芹黄素-8-C-β-D-吡喃葡萄糖苷(3)、肥皂草苷(4)、芹黄素-7-O-槐糖苷(5)、异牡荆素-2″-O-β-D -吡喃葡萄糖苷(6).除化合物4为首次从该植物中分离得到外,其它化合物均为首次从石竹科植物中分离得到.并采用DPPH自由基清除模型对分离得到的化合物进行了抗氧化活性筛选,化合物1显示出强抗氧化活性.     

中药黄芩中4种黄酮类化合物的密度泛函理论研究

采用DFT B3LYP方法在6-311G(d)基组下优化计算了黄芩苷、黄芩素、汉黄芩苷和汉黄芩素,分别从自然电荷分布、酚羟基的解离焓及前线轨道等方面分析了它们的活性.结果表明;4个分子C5处酚羟基氢原子上的正电荷数都是最大的,所带正电荷顺序是:黄芩苷>黄芩素>汉黄芩素>汉黄芩苷;酚羟基的解离能分析得到抗氧化活性顺序与其相同;最高占据轨道和最低空轨道的能级差ΔE的顺序是:黄芩苷<汉黄芩苷<黄芩素<汉黄芩素.黄芩苷消除.OH自由基的过渡态计算得到的活化能是113.2kJ.mol-1,反应热为-1 053kJ.mol-1.各种计算数据都表明黄芩苷在这四种黄酮化合物中的活性最大,消除自由基的理论活性顺序与文献报道的顺序一致.     

基于2′，4′-二氟联苯基的新型1， 2， 4-三氮唑类化合物的合成及其抗真菌活性

依据药物分子设计原理,设计合成了以 2′, 4′-二氟代联苯基为分子骨架的新型1, 2, 4-三氮唑化合物.目标化合物分子结构经核磁共振氢谱(1H NMR )、碳谱(13C NMR)、高分辨质谱(HRMS-ESI)进行确证.测试了目标化合物的体外抗真菌活性,测试结果表明,目标化合物5d, 5e, 6a, 6b, 7c的抗真菌活性较好, 化合物5d, 6a对白色念珠菌的抑菌活性和酮康唑、氟康唑的抑菌活性相当,化合物5d, 5e, 6a, 7c对红色毛癣菌的抑菌活性接近酮康唑,优于氟康唑.     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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