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前线轨道在黄铜矿捕收剂开发中的应用 被引量:33
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作者 孙伟 杨帆 +2 位作者 胡岳华 何国勇 刘文莉 《中国有色金属学报》 EI CAS CSCD 北大核心 2009年第8期1524-1532,共9页
利用量子化学软件GW03和FUJISTU CAChe计算黄原酸甲酸酯类、乙氧羰基硫氨酯类黄铜矿捕收剂的前线轨道的性质—HOMO能量、HOMO形状以及药剂组成原子的HOMO密度,并结合这两类药剂的浮选结果研究这些量化参数与药剂选择性之间的联系,探讨... 利用量子化学软件GW03和FUJISTU CAChe计算黄原酸甲酸酯类、乙氧羰基硫氨酯类黄铜矿捕收剂的前线轨道的性质—HOMO能量、HOMO形状以及药剂组成原子的HOMO密度,并结合这两类药剂的浮选结果研究这些量化参数与药剂选择性之间的联系,探讨这些参数作为选择黄铜矿捕收剂判据的可行性。结果表明:对于同种类型的捕收剂,其选择性与HOMO能量呈线性关系,依据HOMO能量能较准确地预测这两种捕收剂的选择性能;对于不同种类的捕收剂,通过对HOMO形状以及组成原子的HOMO密度的讨论可知,乙氧羰基硫氨酯类捕收剂的选择性能要比黄原酸甲酸酯类捕收剂的强。因此,这3项参数综合起来可以评价黄铜矿捕收剂的选择性能。 展开更多
关键词 homo 浮选捕收剂 黄原酸甲酸酯 乙氧羰基硫氨酯 黄铜矿
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甲烷在外场作用下的光激发特性研究 被引量:27
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作者 徐国亮 朱正和 +1 位作者 马美仲 谢安东 《物理学报》 SCIE EI CAS CSCD 北大核心 2005年第7期3087-3093,共7页
采用密度泛函B3LYP和组态相互作用方法在6311++G水平上计算了甲烷从基态到前六个激发态的跃迁波长,振子强度,自发辐射系数An0和吸收系数B0n(n=1—6).同时研究了外电场对甲烷分子的激发态的影响规律.结果表明,随外电场强度增大,系统总能... 采用密度泛函B3LYP和组态相互作用方法在6311++G水平上计算了甲烷从基态到前六个激发态的跃迁波长,振子强度,自发辐射系数An0和吸收系数B0n(n=1—6).同时研究了外电场对甲烷分子的激发态的影响规律.结果表明,随外电场强度增大,系统总能量变化较小,同时最高占据轨道HOMO与最低空轨道LUMO的能隙gaps变小,费米能级Fermilevels略有下降.甲烷基态(X~1A1)在外场作用下,易于向高激发态产生跃迁. 展开更多
关键词 外场作用 特性研究 光激发 自发辐射系数 最高占据轨道 B3LYP 跃迁波长 作用方法 密度泛函 振子强度 影响规律 甲烷分子 吸收系数 电场强度 能量变化 LUMO homo 费米能级 高激发态 外电场 基态 能隙
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Climate indexes of phytoliths from Homo erectus' cave deposits in Nanjing 被引量:17
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作者 Weiming Wang Jinling Liu Xiaodan Zhou 《Chinese Science Bulletin》 SCIE EI CAS 2003年第18期2005-2009,共4页
A study on phytoliths and their climate indexes is carried out from Homo erectus?cave deposits in HuluCave, Nanjing. Evidence shows that phytolith assemblages of the cave deposits are dominated by the cold resistant t... A study on phytoliths and their climate indexes is carried out from Homo erectus?cave deposits in HuluCave, Nanjing. Evidence shows that phytolith assemblages of the cave deposits are dominated by the cold resistant types with a lower warm index, reflecting an overall cold inclined climate. This possibly connects the cave deposits with glacial climate to a great extent, which is in accordance with thenorthern fauna revealed by fossil mammals and temperateclimate indicated by pollen assemblages. According to the distributional state of the phytoliths and their climate in-dexes on 4 profiles in the cave, it is revealed that profiles Ⅰand Ⅱ display certain cold/warm, and dry/wet fluctuations; profile Ⅲ shows a humid and cold condition with the high-est humility in the cave deposits; while profile Ⅳ indicates a possible quick accumulating process because of its stableclimate indexes except for its bottom and top. 展开更多
关键词 CLIMATE indexes PHYTOLITHS NANJING homo erectus CAVE deposits.
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4种儿茶素生物活性密度泛函理论的研究 被引量:13
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作者 吕庆章 王珂芳 +2 位作者 牛静 李小娟 卢雁 《计算机与应用化学》 CAS CSCD 北大核心 2008年第12期1526-1530,共5页
绿茶中的4种儿茶素EGCG,ECG,EGC,和EC具有抗氧化、抗癌等生物活性,对人体健康有很好的保护作用。分子的抗氧化机制主要通过酚羟基的抽氢反应直接消除自由基。本文利用密度泛函(DFT)B3LYP法在6-31G^*基组下计算了这4个分子,分别... 绿茶中的4种儿茶素EGCG,ECG,EGC,和EC具有抗氧化、抗癌等生物活性,对人体健康有很好的保护作用。分子的抗氧化机制主要通过酚羟基的抽氢反应直接消除自由基。本文利用密度泛函(DFT)B3LYP法在6-31G^*基组下计算了这4个分子,分别从分子的电荷分布、4个分子与失去带最大正电荷的酚羟基氢原子形成自由基反应的生成热之差(AHOF)、最高占据轨道、最高占据轨道和最低空轨道的能级差等方面分析儿茶素消除自由基的机理。结果表明在4个儿茶素分子中带最大正电荷的氢原子,在不同的酚羟基上。EGCG和EGC分子中位于B环的4'位酚羟基上,ECG分子中位于D环的4"位酚羟基上,EC分子中位于B环的3'位酚羟基上;4个分子中其氢所带正电荷的大小顺序是EGCG〉ECG〉EGC〉EC,与文献记载的消除自由基活性顺序一致;从AHOF可以看出,儿茶素消除自由基的反应活性与酚羟基的个数和失去氢原子后形成内氢键的个数有关;另外,最高占据轨道和最低空轨道的能级差在一定程度上也反映4个分子的活性。 展开更多
关键词 儿茶素 自由基 密度泛函 电荷分布 △HOF 最高占据轨道 能级差
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记陕西长武晚更新世人牙及共生哺乳动物化石 被引量:11
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作者 黄万波 郑绍华 《人类学学报》 1982年第1期14-17,共4页
1972年10月,作者在陇东进行第四纪哺乳动物和地层考察期间,在陕西省长武县城关附近的窑头沟及鸭儿沟观察了几个晚更新世地层剖面,并且在这些剖面的中、下部灰色砂质土及砂砾层找到了许多石器和少量哺乳动物化石。此外,还获得了一枚化石... 1972年10月,作者在陇东进行第四纪哺乳动物和地层考察期间,在陕西省长武县城关附近的窑头沟及鸭儿沟观察了几个晚更新世地层剖面,并且在这些剖面的中、下部灰色砂质土及砂砾层找到了许多石器和少量哺乳动物化石。此外,还获得了一枚化石智人牙齿。通过这些材料的简单记述(石器材料将另文发表),作者希望对黄土高原晚更新世哺乳动物和地层时代的认识有所帮助。 展开更多
关键词 智人 地层 动物群
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前线轨道理论在化学中的应用 被引量:6
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作者 刘衍贞 《潍坊学院学报》 2002年第2期42-44,共3页
前线轨道理论认为 :分子在反应过程中是分子轨道起变化 ,优先起作用的是前线轨道 ,即分子中的最高被电子占有分子轨道 (HOMO)和最低空分子轨道 (LUMO) 。
关键词 前线轨道理论 homo 最高被占轨道 LUMO 最低空轨道 对称性匹配 对称性禁阻 化学
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咪唑啉酮类化合物的量子化学研究 被引量:7
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作者 王瑾玲 孙命 +2 位作者 苏华庆 翟秀红 缪方明 《计算机与应用化学》 CAS CSCD 1999年第4期272-274,279,共4页
采用 P M3 方法对灭草烟分子的4 种构象进行了量子化学计算, 进一步证实了模板分子构象的正确性;计算了19 种5取代咪唑啉酮化合物的原子净电荷、前线分子轨道能级分布, 讨论了它们可能的活性部位, 为咪唑啉酮类除草剂的合... 采用 P M3 方法对灭草烟分子的4 种构象进行了量子化学计算, 进一步证实了模板分子构象的正确性;计算了19 种5取代咪唑啉酮化合物的原子净电荷、前线分子轨道能级分布, 讨论了它们可能的活性部位, 为咪唑啉酮类除草剂的合理设计提供了良好的理论基础。 展开更多
关键词 咪唑啉酮化合物 量子化学 除草剂
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从赤裸生命到荣耀政治——浅论阿甘本homo sacer思想的发展谱系 被引量:9
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作者 蓝江 《黑龙江社会科学》 CSSCI 2014年第4期1-10,共10页
在阿甘本的著作中,homo sacer是其最难理解的概念之一。1995年阿甘本最初提出了homo sacer概念,这一概念具有双重例外的特殊含义,以及其在例外状态下的存在模式。阿甘本近期的新著作主要有《语言的圣礼》《王国与荣耀》《业主》等,进一... 在阿甘本的著作中,homo sacer是其最难理解的概念之一。1995年阿甘本最初提出了homo sacer概念,这一概念具有双重例外的特殊含义,以及其在例外状态下的存在模式。阿甘本近期的新著作主要有《语言的圣礼》《王国与荣耀》《业主》等,进一步考察这些著作,从而梳理阿甘本从早期的对政治纯粹生命性的关怀,以及更为深入地从中世纪直到近代脉络中找寻到剖析homo sacer得以生成内在于西方文化和政治核心处的奥秘,具有现实的学术意义。 展开更多
关键词 homo sace 赤裸生命 荣耀政治 阿甘本
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Prediction of the Photofading of Selected Derivatives of 5-(4-X-Phenylazo)-3-Cyano-1-(H or Ethyl)-6-Hydroxy-4-Methyl-2-Pyridone: Theoretical Studies, Comparison of AM1 and PM3 Methods
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作者 Krzysztof Wojciechowski Lucjan Szuster 《Computational Chemistry》 CAS 2024年第2期25-56,共32页
We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic (O2•−) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of d... We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic (O2•−) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of durability and the probability of their formation. We performed the light fastness calculations of the monoazopyridone dyes. Using the semi-empirical methods of quantum chemistry AM1 and PM3, the reactivity indicators of superdelocalisability (SrE(N)) and the electron density distribution in ground state on the highest occupied HOMO orbital and the lowest unoccupied excited state LUMO in 2-pyridone phenylazo derivatives were calculated. Superdelocalisability coefficients enable the stability to oxidising agents of various chemical molecules depending on the tautomeric forms in which they may occur. The results of the electron density calculations at the HOMO and LUMO boundary orbitals allow to determine the tendency to electrophilic attack with singlet oxygen 1O2 or nucleophilic attack of the superoxide anion O2•−on a specific atom in the molecule. The structure of the dyes was optimised with MM+, MD and AM1 or PM3 until a constant energy value was achieved with a convergence criterion of 0.01 kcal/mol. 展开更多
关键词 Photochemical Degradation AM1 and PM3 Methods Boundary Orbitals Electron Densities Electrophilic and Nucleophilic Reaction homo and LUMO Orbitals
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含有芘基团的电致发光材料的研究进展 被引量:5
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作者 薛震 高昌轩 +1 位作者 卢明宝 张玉祥 《广州化工》 CAS 2010年第2期31-34,共4页
综述了近几年芘的衍生物在有机电致发光中的研究情况,展示了一些新结构并做了分析,总结了含芘基团电致发光材料的优点和缺点,并指出了芘的衍生物在有机电致发光材料中的应用前景。
关键词 homo LUMO OLED
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TIMS U-series ages of speleothems from the Tangshan caves, Nanjing 被引量:5
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作者 Yongjin Wang Cheng Hai +3 位作者 Conglun Luo Yingfei Xia Jiangying Wu Jun Chen 《Chinese Science Bulletin》 SCIE EI CAS 1999年第21期1987-1991,共5页
U-series ages of a set of speleothem samples from the two caves near Tangshan Town, Nanjing, determined by thermal ionization mass spectrometry (TIMS), range from older than 500 KaBP to around 20 kaBP. These dated spe... U-series ages of a set of speleothem samples from the two caves near Tangshan Town, Nanjing, determined by thermal ionization mass spectrometry (TIMS), range from older than 500 KaBP to around 20 kaBP. These dated speleothems with unequivocal stratigraphic layers in cave sediments provide basic data to establish a geochronologic sequence for the 展开更多
关键词 SPELEOTHEM U-SERIES age homo erectus Nanjing.
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Homo Faber Scapegoated, or Apocalyptic Artificial Intelligence: Rethinking the Technological Singularity Concept From the Synergetic Historicism Position
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作者 Irina Gennadievna Mikailova 《Journal of Philosophy Study》 2023年第11期496-506,共11页
The article is focused on discussing a new methodological approach to the study on specifics of transferring human beings to the posthuman cyber society.The approach in question assists in rethinking interconnected pr... The article is focused on discussing a new methodological approach to the study on specifics of transferring human beings to the posthuman cyber society.The approach in question assists in rethinking interconnected problems both of human origins in the universe and mankind’s digital future.And,besides,such an approach allows to deal with self-organising interconversions between the poles of the cardinal dual opposition of the Global Noosphere Brain and the Artificial General Intelligence.Herewith such phenomena of digital social life as Global Digitalisation,Digital Immortality,Mindcloning,and Technological Zombification being the constituents of Technological Singularity Concept,are rethought as paving the way for oncoming Posthuman Digital Era.This concept is evidently exemplified by a bifurcation resulting in two alternatives to be chosen by human beings,to wit,either to be undergone Mindcloning and become digitally immortal or being destroyed by powerful intelligent machines.The investigation in question is based on such a progressive methodology as the Law of Self-Organizing Ideals,as well as on the Method of Dual Oppositions.Rethinking interrelationships between the problem of a sense of social history and the meaning-of-life of local societies members which any intelligent machine is devoid of permits to substantiate specific regularities of Self-Transforming Homo Faber into Homo Digitalis and Technological Zombies ready to be transferred to posthuman cyberspace. 展开更多
关键词 Law of Self-Organising Ideals dual oppositions homo Faber homo Digitalis Technological Singularity Artificial General Intelligence cyber society cyberspace Mindcloning mindware mindfiles Synergetic Historicism
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Electronic structure and flotation behavior of monoclinic and hexagonal pyrrhotite 被引量:6
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作者 赵翠华 吴伯增 陈建华 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第2期466-471,共6页
Electronic structures of monoclinic and hexagonal pyrrhotite were studied using density functional theory method,together with their flotation behavior. The main contribution of monoclinic pyrrhotite is mainly from Fe... Electronic structures of monoclinic and hexagonal pyrrhotite were studied using density functional theory method,together with their flotation behavior. The main contribution of monoclinic pyrrhotite is mainly from Fe 3d, while that of hexagonal pyrrhotite is from Fe 3d, Fe 3p and S 3s. The hexagonal pyrrhotite is more reactive than monoclinic pyrrhotite because of large density of states near the Fermi level. The hexagonal pyrrhotite shows antiferromagnetism. S—Fe bonds mainly exist in monoclinic pyrrhotite as the covalent bonds, while hexagonal pyrrhotite has no covalency. The main contributions of higest occupied molecular orbital(HOMO) and lowest unoccupied molecular obital(LUMO) for monoclinic pyrrhotite come from S and Fe. The main contribution of HOMO for hexagonal pyrrhotite comes from Fe, while that of LUMO comes from S. The coefficient of Fe atom is much larger than that of S atom of HOMO for hexagonal pyrrhotite, which contributes to the adsorption of Ca OH+ on the surface of hexagonal pyrrhotite when there is lime. As a result, lime has the inhibitory effect on the floatation of hexagonal pyrrhotite and the coefficient of Fe is very close to that of S for monoclinic pyrrhotite. Therefore, the existence of S prevents the adsorption of Ca OH+on the surface of monoclinic pyrrhotite, which leads to less inhibitory effect on the flotation of monoclinic pyrrhotite. 展开更多
关键词 monoclinic pyrrhotite hexagonal pyrrhotite electronic structure flotation behavior density functional theory
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苯乙烯与苯酚反应的前线轨道理论分析 被引量:4
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作者 何伟平 黄菊 +1 位作者 王德堂 刘晓静 《原子与分子物理学报》 北大核心 2017年第2期231-237,共7页
采用密度泛函理论的M062X方法和6-311G(d,p)基组,对苯乙烯与苯酚的反应进行了分子轨道理论计算.通过讨论反应过程中各分子的最高占据轨道(HOMO)和最低空轨道(LUMO),预测了化学反应的方向和相应的反应产物.经过前线轨道理论分析,得出苯... 采用密度泛函理论的M062X方法和6-311G(d,p)基组,对苯乙烯与苯酚的反应进行了分子轨道理论计算.通过讨论反应过程中各分子的最高占据轨道(HOMO)和最低空轨道(LUMO),预测了化学反应的方向和相应的反应产物.经过前线轨道理论分析,得出苯乙烯与苯酚反应的关键步骤是形成苯乙烯基碳正离子,反应中H+起到催化作用;反应产物主要有4-(1-苯基乙基)苯酚、2-(1-苯基乙基)苯酚、2,4-双-(1-苯基乙基)苯酚、2,4,6-三-(1-苯基乙基)苯酚(SP-3)、1,3-二苯基丁烯和4-(1,2-二苯丙基)苯酚. 展开更多
关键词 苯乙烯 苯酚 化学反应 前线轨道 homo LUMO
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Electronic properties of 2D materials and their junctions
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作者 Taposhree Dutta Neha Yadav +8 位作者 Yongling Wu Gary J.Cheng Xiu Liang Seeram Ramakrishna Aoussaj Sbai Rajeev Gupta Aniruddha Mondal Zheng Hongyu Ashish Yadav 《Nano Materials Science》 EI CAS CSCD 2024年第1期1-23,共23页
With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific community.Despite tremendous advancements in exploratory research on 2... With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific community.Despite tremendous advancements in exploratory research on 2D materials,knowledge of 2D electrical transport and carrier dynamics still in its infancy.Thus,here we highlighted the electrical characteristics of 2D materials with electronic band structure,electronic transport,dielectric constant,carriers mobility.The atomic thinness of 2D materials makes substantially scaled field-effect transistors(FETs)with reduced short-channel effects conceivable,even though strong carrier mobility required for high performance,low-voltage device operations.We also discussed here about factors affecting 2D materials which easily enhanced the activity of those materials for various applications.Presently,Those 2D materials used in state-of-the-art electrical and optoelectronic devices because of the extensive nature of their electronic band structure.2D materials offer unprecedented freedom for the design of novel p-n junction device topologies in contrast to conventional bulk semiconductors.We also,describe the numerous 2D p-n junctions,such as homo junction and hetero junction including mixed dimensional junctions.Finally,we talked about the problems and potential for the future. 展开更多
关键词 2D materials Electrical properties p-n junctions Mixed hereto junctions homo junctions Electrical transport
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最高已占轨道电子分布图在亲电取代定位规律中的应用 被引量:6
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作者 王文峰 丁开宁 +1 位作者 李奕 李俊篯 《化学教育》 CAS 2005年第7期60-62,共3页
影响芳环亲电取代定位规律的因素中,除了总π电子密度大小以外,芳环HOMO电子在各个C上的密度分布也是一个重要因素。本文采用B3LYP方法计算了3个芳香化合物的HOMO电子密度图,定性解释了它们的亲电取代定位效应。
关键词 亲电取代 定位规律 分布图 B3LYP方法 应用 轨道 芳香化合物 电子密度 密度分布 homo 定位效应 定性解释 密度图 芳环 π
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Computational interaction analysis of organophosphorus pesticides with different metabolic proteins in humans 被引量:3
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作者 Amit Kumar Sharma Karuna Gaur +1 位作者 Rajeev Kumar Tiwari Mulayam Singh Gaur 《The Journal of Biomedical Research》 CAS 2011年第5期335-347,共13页
Pesticides have the potential to leave harmful effects on humans, animals, other living organisms, and the environment. Several human metabolic proteins inhibited after exposure to organophosphorus pesticides absorbed... Pesticides have the potential to leave harmful effects on humans, animals, other living organisms, and the environment. Several human metabolic proteins inhibited after exposure to organophosphorus pesticides absorbed through the skin, inhalation, eyes and oral mucosa, are most important targets for this interaction study. The crystal structure of five different proteins, PDBIDs: 3LII, 3NXU, 4GTU, 2XJ1 and 1YXA in Homo sapiens (H. sapiens), interact with organophosphorus pesticides at the molecular level. The 3-D structures were found to be of good quality and validated through PROCHECK, ERRAT and ProSA servers. The results show that the binding energy is maximum -45.21 relative units of cytochrome P450 protein with phosmet pesticide. In terms of H-bonding, methyl parathion and parathion with acetylcholinesterase protein, parathion, methylparathion and phosmet with protein kinase C show the highest interaction. We conclude that these organophosphorus pesticides are more toxic and inhibit enzymatic activity by interrupting the metabolic pathways in H. sapiens. 展开更多
关键词 DOCKING organophosphorus pesticides comparative analysis MODELING toxicity analysis acetylcholinesterases homo sapiens
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Gene polymorphisms associated with sudden decreases in heart rate during extensive peritoneal lavage with distilled water after gastrectomy 被引量:1
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作者 Shuang Yao Yan Yuan +2 位作者 Jun Zhang Yang Yu Guang-Hua Luo 《World Journal of Gastrointestinal Surgery》 SCIE 2023年第10期2154-2170,共17页
BACKGROUND Our previous study found that the telomerase-associated protein 1(TEP1,rs938886 and rs1713449)and homo sapiens RecQ like helicase 5(RECQL5,rs820196)single nucleotide polymorphisms(SNPs)were associated with ... BACKGROUND Our previous study found that the telomerase-associated protein 1(TEP1,rs938886 and rs1713449)and homo sapiens RecQ like helicase 5(RECQL5,rs820196)single nucleotide polymorphisms(SNPs)were associated with changes in heart rate(HR)≥30%during peritoneal lavage with distilled water after gastrectomy.This study established a single tube method for detecting these three SNPs using two-dimensional(2D)polymerase chain reaction(PCR),and investigated whether SNP-SNP and SNP-environment interactions increase the risk of high HR variability(HRV).AIM To investigate whether genotypes,genetic patterns,SNP-SNP and SNP-environment interactions were associated with HRV.METHODS 2D PCR was used to establish a single-tube method to detect TEP1 rs938886 and rs1713449 and RECQL5 rs820196,and the results were compared with those of sanger sequencing.After adjusting for confounders such as age,sex,smoking,hypertension,and thyroid dysfunction,a nonconditional logistic regression model was used to assess the associations between the genotypes and the genetic patterns(codominant,dominant,overdominant,recessive,and additive)of the three SNPs and a risk≥15%or≥30%of a sudden drop in HR during postoperative peritoneal lavage in patients with gastric cancer.Gene-gene and geneenvironment interactions were analyzed using generalized multifactor dimensionality reduction.RESULTS The coincidence rate between the 2D PCR and sequencing was 100%.When the HRV cutoff value was 15%,the patients with the RECQL5(rs820196)TC genotype had a higher risk of high HRV than those who had the TT genotype(odds ratio=1.97;95%CI:1.05-3.70;P=0.045).Under the codominant and overdominant models,the TC genotype of RECQL5(rs820196)was associated with a higher risk of HR decrease relative to the TT and TT+CC genotypes(P=0.031 and 0.016,respectively).When the HRV cutoff value was 30%,patients carrying the GC-TC genotypes of rs938886 and rs820196 showed a higher HRV risk when compared with the GG–TT genotype carriers(P=0.01).In the three-factor model of rs 展开更多
关键词 homo sapiens RecQ like helicase 5 Telomerase-associated protein 1 Polymorphism Peritoneal lavage Heart rate variability Two-dimensional polymerase chain reaction
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O-glycosyltransferases from Homo sapiens contributes to the biosynthesis of Glycyrrhetic Acid 3-O-mono-β-D-glucuronide and Glycyrrhizin in Saccharomyces cerevisiae 被引量:5
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作者 Ke Xu Yu-jia Zhao +5 位作者 Nadeem Ahmad Jing-nan Wang Bo Lv Ying Wang Jun Ge Chun Li 《Synthetic and Systems Biotechnology》 SCIE 2021年第3期173-179,共7页
Glycyrrhizin(GL)and Glycyrrhetic Acid 3-O-mono-β-D-glucuronide(GAMG)are the typical triterpenoid glycosides found in the root of licorice,a popular medicinal plant that exhibits diverse physiological effects and phar... Glycyrrhizin(GL)and Glycyrrhetic Acid 3-O-mono-β-D-glucuronide(GAMG)are the typical triterpenoid glycosides found in the root of licorice,a popular medicinal plant that exhibits diverse physiological effects and pharmacological manifestations.However,only few reports are available on the glycosylation enzymes involved in the biosynthesis of these valuable compounds with low conversion yield so far.In mammals,glycosyltransferases are involved in the phase II metabolism and may provide new solutions for us to engineer microbial strains to produce high valued compounds due to the substrate promiscuity of these glycosyltransferases.In this study,we mined the genomic databases of mammals and evaluated 22 candidate genes of O-glycosyltransferases by analyzing their catalytic potential for O-glycosylation of the native substrate,glycyrrhetinic acid(GA)for its glycodiversification.Out of 22 selected glycosyltransferases,only UGT1A1 exhibited high catalytic performance for biosynthesis of the key licorice compounds GL and GAMG.Molecular docking results proposed that the enzymatic activity of UGT1A1 was likely owing to the stable hydrogen bonding interactions and favorite conformations between the amino acid residues around substrate channels(P82~R85)and substrates.Furthermore,the complete biosynthesis pathway of GL was reconstructed in Saccharomyces cerevisiae for the first time,resulting in the production of 5.98±0.47 mg/L and 2.31±0.21 mg/L of GL and GAMG,respectively. 展开更多
关键词 O-glycosyltransferase homo sapiens Glycyrrhizin(GL) Saccharomyces cerevisiae Glycyrrhetic Acid 3-O-mono-β-D-glucuronide(GAMG)
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烯烃催化加氢反应的讨论 被引量:2
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作者 梁丽华 《松辽学刊(自然科学版)》 2000年第1期56-56,59,共2页
本文用前线轨道理论讨论烯烃在催化剂存在下的加氢反应 。
关键词 前线轨道理论 烯烃 催化剂 加氢反应 顺式加成
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