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Amphiphilic dendronized homopolymers

2001年全国沉积学大会

作者： Li Yong , Philip A.Allen , Xu Qiang and A.L.Densmore(l.institute of Sedimentary geology, chengdu University of Technology, chengdu, 610059.P.R.china 2.institute of geology,department of earth science, sonneggstrasse 5,eth zentrum,ch-8092 zurich, switzerland 3.chengdu institute of geology and Mineral Resources,chengdu, 610082, P.R. china)

＜正＞ Longmen Shah foreland basin is one of typical foreland basin along eastern margin of Tibetan Plateau. The tectono-stratigraphic evolution of the foreland basin, which lies at western flanks of Yangtze Craton can be divided two major stages: a cratonic stage characterized by the deposition of platform carbonates on the western Yangtze Craton during Sinian-middle Triassic times, a Late Triassic to Quaternary foreland basin stage characterized by marine--continental clastic sedimentation. Depending on sedimentary characteristic in strata section of outcrop, sedimentary mapping, borehole and seismic reflection profile, the Late Triassic-Quaternary stratigraphy with more than 10000m in Longmen Shan foreland basin has been divided into six

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science china chemistry 2010年第12期53卷 2509-2519页

作者： LI Wen 1 & ZHANG AFang 1,2 1 institute of Polymers,department of Materials,eth zurich,Wolfgang-Pauli-Str.10,8093 zurich,switzerland 2 department of Polymer Materials,College of Materials science and Engineering,Shanghai University,Shanghai 201800,china institute of Polymers Department of Materials ETH Zurich Zurich Switzerland department of Polymer Materials College of Materials Science and Engineering Shanghai University Shanghai China

A series of second generation of amphiphilic dendronized homopolymers are efficiently synthesized,and their thermoresponsiveness in aqueous solutions and secondary structures in methanol solutions are *** polymers are constructed in each repeat unit with various generations of hydrophobic 4-aminoproline and hydrophilic oligoethylene glycol (OEG)-based dendrons,and their over-all hydrophilicity is tuned by varying these dendron *** with or without the first generation of proline dendron show good water solubility at room temperature,but exhibit typical thermoresponsive behaviors at elevated temperatures as characterized by turbidity measurements using UV-vis spectroscopy,while the polymer with the secondary generation of proline dendron is not soluble in *** polymers show ordered secondary structures as evidenced by the optical rotation and circular dichroism ***,assembly of these amphiphilic homopolymers into porous films via breath figure (BF) technique is described,and polymer structures are found to show significant influence on the morphology of porous film.

关键词： amphiphilic polymer dendronized polymer dendritic macromolecule supramolecular structure

Bile acids,gut microbiota,and therapeutic insights in hepatocellular carcinoma

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Cancer Biology & Medicine 2024年第2期21卷 144-162页

作者： Yang Song Harry ch Lau Xiang Zhang Jun Yu institute of Digestive Disease and department of Medicine and Therapeutics State Key Laboratory of Digestive DiseaseLi Ka Shing Institute of Health SciencesCUHK Shenzhen Research InstituteThe Chinese University of Hong KongHong KongChina department of Gastroenterology Zhongshan Hospital Xiamen UniversityXiamen 361004China

Hepatocellular carcinoma(HCC)is a prevalent and aggressive liver *** interplay between bile acids(BAs)and the gut microbiota has emerged as a critical factor in HCC development and *** normal conditions,BA metabolism is tightly regulated through a bidirectional interplay between gut microorganisms and *** gut microbiota plays a critical role in BA metabolism,and BAs are endogenous signaling molecules that help maintain liver and intestinal *** note,dysbiotic changes in the gut microbiota during pathogenesis and cancer development can disrupt BA homeostasis,thereby leading to liver inflammation and fibrosis,and ultimately contributing to HCC ***,understanding the intricate interplay between BAs and the gut microbiota is crucial for elucidating the mechanisms underlying *** this review,we comprehensively explore the roles and functions of BA metabolism,with a focus on the interactions between BAs and gut microorganisms in ***,therapeutic strategies targeting BA metabolism and the gut microbiota are discussed,including the use of BA agonists/antagonists,probiotic/prebiotic and dietary interventions,fecal microbiota transplantation,and engineered *** summary,understanding the complex BA-microbiota crosstalk can provide valuable insights into HCC development and facilitate the development of innovative therapeutic approaches for liver malignancy.

关键词： Bile acid gut microbiota hepatocellular carcinoma therapeutics microbiota modulation

Phosphine/Benzocyclone-based Neutral Nickel Catalysts for ethylene Polymerization and Copolymerization with Polar Monomers

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chinese Journal of Polymer science 2024年第2期42卷 202-212,I0007页

作者： Fei Wang Li Pan Vladislav A.Tuskaev Svetlana ch.Gagieva Yue-Sheng Li Tianjin Key Lab of Composite&Functional Materials School of Material Science and EngineeringTianjin UniversityTianjin300072China department of chemistry Lomonosov Moscow State UniversityRussian Federation InstitutionLeninskie Gory 1Moscow119991Russian Federation A N Nesmeyanov institute of Organoelement Compounds Russian Academy of SciencesVavilova st.28Moscow119991Russian Federation

The efficient copolymerization of olefin with polar monomers using nickel-based catalysts presents a longstanding challenge. In this contribution, three phosphine-benzocyclone ligands and corresponding neutral nickel catalysts(Ni1: Ar = Ph;Ni2: Ar = 2-(C_(6)H_(5))C_(6)H_(4);Ni3: Ar = 2-[2',6'-(Me O)_(2)-C_(6)H3]C_(6)H_(4)) were prepared and applied for the ethylene polymerization and copolymerization with polar monomers without any cocatalyst. The bulky substituent groups in complexes Ni2 and Ni3 contributed to high catalytic activities(up to 7.24×10^(6) and 9.04×10^(6)g·mol Ni^(-1)·h^(-1), respectively), and produced high-molecular-weight polyethylene(Mw up to 545.7 k Da). Complex Ni3 exhibited high activities for ethylene polymerization at the level of 10^(6) g·mol Ni^(-1)·h^(-1) across a wide range from 30 ℃ to 120 ℃, exhibiting excellent high temperature tolerance. These nickel complexes were also effectively employed in the copolymerization of ethylene with methyl acrylate, ethyl acrylate, butyl acrylate and lauryl acrylate, producing copolymers with high molecular weights(Mw up to 80.5 k Da) and high polar monomer incorporation(up to 8.2 mol%). Microstructure analyses revealed that the introduction of large sterically hindered substituents facilitated the incorporation of polar functional units into the polymer backbone. This study demonstrates the potential of these nickel-based catalysts for efficient copolymerization of olefin with polar monomers.

关键词： Neutral nickel catalyst ethylene polymerization Copolymerization Polar acrylate monomers

The microtine distribution and its environmental significance since the Middle Pleistocene in Zhangping Caves of the Qinling Mountains

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science china earth sciences 2008年第2期51卷 294-299页

作者： LI YongXiang1 & XUE XiangXu1,2 1 State Key Laboratory of Continental Dynamics, department of geology, Northwest University, institute of Cenozoic geology and Environment, Xi’an 710069, china 2.institute of earth Environment, State Key Laboratory of Loess and Quaternary geology, chinese Academy of sciences, Xi’an 710075, china State Key Laboratory of Continental Dynamics Department of Geology Northwest University Institute of Cenozoic Geology and Environment institute of earth Environment State Key Laboratory of Loess and Quaternary Geology Chinese Academy of Sciences

Three microtine species are recovered from the Zhangping Caves of the Qingling Mountains, namely Microtus oeconomus, Caryomys inez and Caryomys eva. They are climate-sensitive ones with different ecological habits, therefore their distribution well corresponds to environmental variations. Statistical comparison of the distribution of fossil microtines and their counterparts nowadays displays that the climate variation of the studied area and its contiguity since the middle Pleistocene are: warm and humid at 493 ka ago, cool and humid at 259 ka ago―cold and humid at 205 ka ago―cool and humid at 28 ka ago, and warm and dry at present.

关键词： environmental variation since Middle Pleistocene microtine fossils Zhangping Caves of the Qinling Mountains

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咖啡因的科学共识

中国食品学报 2024年第6期24卷 498-504页

作者：中国食品科学技术学会北京100048

咖啡因是一种常见于咖啡、茶叶和可可等植物中的天然活性成分,作为功能添加成分已在国际食品领域广泛应用多年,适量摄入有助于健康人群提高注意力,促进运动能力,缓解疲劳。国内外相关食品安全监管机构一致认为,咖啡因虽在日常饮食中的... 详细信息

咖啡因是一种常见于咖啡、茶叶和可可等植物中的天然活性成分,作为功能添加成分已在国际食品领域广泛应用多年,适量摄入有助于健康人群提高注意力,促进运动能力,缓解疲劳。国内外相关食品安全监管机构一致认为,咖啡因虽在日常饮食中的摄入是安全的,但需关注个体差异、摄入量以及频率。许多国家和地区已对咖啡因在食品中的应用制定了严格的应用限量和标识规定。为进一步提升大众对咖啡因的科学认知,消除对咖啡因的偏见,推动咖啡因在相关食品产业的合理应用,中国食品科学技术学会组织食品科学、公共卫生、食品安全与食品营养等领域专家与相关产业界代表,通过现场咨询、文献检索、专题研讨等形式和方法,经广泛讨论形成咖啡因的科学共识,以推动咖啡因在我国的规范使用。

关键词：咖啡因健康益处摄入量应用管理

Genesis of excess argon in phengite and significance of ^(40)Ar-^(39)Ar age spectra for omphacite:A case study on UHP eclogite of South Dabie Terrain,china

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chinese science Bulletin 2000年第15期45卷 1345-1351页

作者： WANG Songshan, GE Ningjie, SANG Haiqing & QIU Ji1. institute of geology and Geophysics, chinese Academy of sciences, Beijing 100029, china 2. department of earth and Space science, University of science and Technology of china, Hefei 230026, china Correspondence should be addressed to Wang Songshan institute of geology and Geophysics Chinese Academy of Sciences Beijing China department of earth and Space science University of Science and Technology of China Hefei China

The Ar-Ar dating of phengite and omphacite in ultrahigh-pressure (UHP) eclogite of Bixiling and Hengchong in the South Dabie Terrain shows that the content range of excess argon is as high as (0.4-1.3)×10 8 mol· g 1. The genesis of the excess argon is discussed. The Ar-Ar age spectra of omphacite could not support the opinion that the UHP metamorphism occurred in Caledon epoch and pre-Caledon epoch.

关键词： South Dabie Terrain ultrahigh-pressure metamorphics phengite omphacite excess argon.

Carbon isotopic characteristics and their genetic relationships for individual lipids in plants and sediments from a marsh sedimentary environment

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science china earth sciences 2005年第8期48卷 1203-1210页

作者： DUAN Yi1, ZHANG Hui1, ZHENG chaoyang1, WU Baoxiang1 & ZHENG Guodong2 1. Lanzhou institute of geology, chinese Academy of sciences, Lanzhou 730000, china 2. department of earth & Planetary System science, Graduate School of science, Hiroshima University, Higashi-Hiroshima 739-85Japan Lanzhou institute of geology Chinese Academy of Sciences Lanzhou China department of earth & Planetary System science Graduate School of Science Hiroshima University Higashi-Hiroshima Japan

The carbon isotopes of individual lipids in herbaceous plants and tree leaves in Ruoergai marsh were measured by the GC-IRMS analytical technique in order to understand the inherent relationships of carbon isotopes between sedimentary and plant lipids from typical marsh environment. The analytical results show that the carbon isotopic compositions of n-alkanes in different kinds of plants differ significantly. Mean δ 13C values of n-alkanes in her-baceous plants (?32.2‰―?36.9‰) are 3.3‰ lower than those in woody plant (?27.2‰― ?35.0‰). The carbon isotopic compositions of fatty acids in organisms (?30.3‰― ?36.2‰) are very similar to those of n-alkanes and the δ 13C values for unsaturated fatty acids are within the range of those for saturated fatty acids. The differences in δ 13C values between plant lipids are obvious and range from 2.4‰ to 7.8‰. It is observed that the carbon isotopic compositions of sedimentary lipids are closely related to those of plant lipids. The carbon isotopic compositions (?27.0‰―?36.9‰) of n-alkanes, ≥C16 fatty acids, n-alkanols, sterols and n-alkanones in the sediments are similar to those of plant lipids and the carbon isotopic compositions of short-chain sedimentary lipids are similar to those of long-chain sedimentary homologues. These indicate that the sedimentary lipids are derived from high plants. However, the δ 13C values of C14:0 and C15:0 fatty acids in the sediments are lighter than those of the same carbon number saturated homologues in plants, reflecting the genetic features partially derived from bacteria. These data provide scientific evidence for carbon isotope-applied research of individual lipids.

关键词： marsh environment, plants, sediments, individual lipids, carbon isotopic compositions, genetic relationships.

Glacial-Interglacial Atmospheric CO_2 change——The Glacial Burial Hypothesis

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Advances in Atmospheric sciences 2003年第5期20卷 677-693页

作者： Ning ZENG department of Meteorology and earth System science Interdisciplinary Center, University of Maryland, USA department of Meteorology and earth System science Interdisciplinary Center University of Maryland

Organic carbon buried under the great ice sheets of the Northern Hemisphere is suggested to be the missing link in the atmospheric CO2 change over the glacial-interglacial cycles. At glaciation, the advancement of continental ice sheets buries vegetation and soil carbon accumulated during warmer periods. At deglaciation, this burial carbon is released back into the atmosphere. In a simulation over two glacial-interglacial cycles using a synchronously coupled atmosphere-land-ocean carbon model forced by reconstructed climate change, it is found that there is a 547-Gt terrestrial carbon release from glacial maximum to interglacial, resulting in a 60-Gt (about 30-ppmv) increase in the atmospheric CO2, with the remainder absorbed by the ocean in a scenario in which ocean acts as a passive buffer. This is in contrast to previous estimates of a land uptake at deglaciation. This carbon source originates from glacial burial, continental shelf, and other land areas in response to changes in ice cover, sea level, and climate. The input of light isotope enriched terrestrial carbon causes atmospheric δ13C to drop by about 0.3‰ at deglaciation, followed by a rapid rise towards a high interglacial value in response to oceanic warming and regrowth on land. Together with other ocean based mechanisms such as change in ocean temperature, the glacial burial hypothesis may offer a full explanation of the observed 80–100-ppmv atmospheric CO2 change.

关键词： atmospheric CO2 ice age glacial burial hypothesis climate

On　the　Mechanism　of　Coal　Mine　Shaft　Damage　Caused　by　Subsidence　in　Xuhuai　Area,Southeast　china

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Communications in Nonlinear science and Numerical Simulation 1997年第2期2卷 19-22+24页

作者： Siwen BI, Xiangdong LOU + & Bing XU + (department of geology, Peking University, Beijing, of china) +(institute of geology chinese Academy of science, People’s Republic of china) department of geology Peking University Beijing 100871 China institute of geology Chinese Academy of Science Beijing China

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关键词： shaft damage caused subsidence numerical modeling