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Effects of hurricane forward speed and approach angle on storm surges:an idealized numerical experiment 预览
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作者 Chenguang Zhang Chunyan Li 《海洋学报:英文版》 SCIE CAS CSCD 2019年第7期48-56,共9页
The effects of hurricane forward speed(V)and approach angle(θ)on storm surge are important and a systematic investigation covering possible and continuous ranges of these parameters has not been done before.Here we p... The effects of hurricane forward speed(V)and approach angle(θ)on storm surge are important and a systematic investigation covering possible and continuous ranges of these parameters has not been done before.Here we present such a study with a numerical experiment using the Finite Volume Community Ocean Model(FVCOM).The hurricane track is simplified as a straight line,such that V andθfully define the motion of the hurricane.The maximum surge is contributed by both free waves and a forced storm surge wave moving with the hurricane.Among the free waves,Kelvin-type waves can only propagate in the down-coast direction.Simulations show that those waves can only have a significant positive storm surge when the hurricane velocity has a down-coast component.The optimal values of V andθthat maximize the storm surge in an idealized semi-circular ocean basin are functions of the bathymetry.For a constant bathymetry,the maximum surge occurs when the hurricane approaches the coast from the normal direction when the free wave generation is minimal;for a stepped bathymetry,the maximum surge occurs at a certain acute approach angle which maximizes the duration of persistent wind forcing;a step-like bathymetry with a sloped shelf is similar to the stepped bathymetry,with the added possibility of landfall resonance when the free and forced waves are moving at about the same velocity.For other cases,the storm surge is smaller,given other parameters(hurricane size,maximum wind speed,etc.)unchanged. 展开更多
关键词 storm SURGE experiments FVCOM HURRICANE forward speed APPROACH ANGLE KELVIN waves forced and free SURGE interactions
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A biotrophic fungal infection of the great burnet Sanguisorba officinalis indirectly affects caterpillar performance of the endangered scarce large blue butterfly Phengaris teleius
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作者 Ewa B. Sliwinska Ratal Martyka +2 位作者 Miroslaw Martyka Mariusz Cichon Piotr Tryjanowski 《昆虫科学:英文版》 SCIE CAS CSCD 2019年第3期555-568,共14页
Interactions between ecological communities of herbivores and microbes are commonly mediated by a shared plant. A tripartite interaction between a pathogenic fungus-host plant-herbivorous insect is an example of such ... Interactions between ecological communities of herbivores and microbes are commonly mediated by a shared plant. A tripartite interaction between a pathogenic fungus-host plant-herbivorous insect is an example of such mutual influences. In such a system a fungal pathogen commonly has a negative influence on the morphology and biochemistry of the host plant, with consequences for insect herbivore performance. Here we studied whether the biotrophic fbngus Podosphaera ferruginea, attacking the great burnet Sanguisorba officinalis, affects caterpillar performance of the endangered scarce large blue butterfly Phengaris teleius. Our results showed that the pathogenic ftmgus affected the number and size of inflorescences produced by food-plants and, more importantly, had in direct, plant-mediated effects on the abun dance, body mass and immune response of caterpillars. Specifically, we found the relationship between caterpillar abundance and variability in inflorescence size on a plant to be positive among healthy food-plants, and negative among infected food-plants. Caterpillars that fed on healthy food-plants were smaller than those that fed on infected food-plants in one studied season, while there was no such difference in the other season. We observed the relationship between caterpillar immune response and the proportion of infected great burnets within a habitat patch to be positive when caterpillars fed on healthy food-plants, and negative when caterpillars fed on infected food-plants. Our results suggest that this biotrophic fungal infection of the great burnet may impose a significant indirect influence on P. teleius caterpillar performance with potential consequences for the population dynamics and structure of this endangered butterfly. 展开更多
关键词 host plant INSECT HERBIVORE Maculinea teleius Podosphaera ferruginea powdery MILDEW TRIPARTITE interactions
Wide bandwidth acoustic transmission via coiled-up metamaterial with impedance matching layers
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作者 Xiao Jia Yang Li +2 位作者 Yinghao Zhou Minghui Hong Ming Yan 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第6期37-44,共8页
Many acoustic metamaterials suffer from a narrow bandwidth transmission because of the impedance mismatch at the airmetamaterial interface. In this paper, a two-dimensional impedance-matched metamaterial with broadban... Many acoustic metamaterials suffer from a narrow bandwidth transmission because of the impedance mismatch at the airmetamaterial interface. In this paper, a two-dimensional impedance-matched metamaterial with broadband transmission performance is investigated. The impedance matching layer is introduced for a gradient variation of effective impedance from the inlet of the unit to the outlet. The effective medium theory and corresponding effective model are used to explain the underlying mechanism. The improved energy transmission of our designs is demonstrated by experiment and numerical simulation within a broad frequency bandwidth over 6 kHz. Our impedance-matched design can be used to enhance sound absorption, which is expected to present improved acoustic performance in the applications of acoustic damper and muffler. 展开更多
关键词 general linear ACOUSTICS structural ACOUSTICS and vibration acoustical measurements and INSTRUMENTATION wavestructure INTERACTIONS
Effects of Main-chain and Chain-ends on the Organogelation of Stearoyl Appended Pendant Valine Based Polymers
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作者 Mridula Nandi Swagata Pan +1 位作者 Dipannita Ghosh Priyadarsi De 《高分子科学:英文版》 SCIE CAS CSCD 2019年第9期903-911,共9页
In this work, we investigated the effect of hydrophobic interactions between the polymeric backbone and chain-end groups on the self-assembly pathway of stearoyl appended side-chain valine (Val)-based poly(methacrylat... In this work, we investigated the effect of hydrophobic interactions between the polymeric backbone and chain-end groups on the self-assembly pathway of stearoyl appended side-chain valine (Val)-based poly(methacrylate/acrylate) homopolymers in different organic hydrocarbons. Gelation studies conducted revealed that while polymers with polyacrylate as backbone induces gelation in several organic hydrocarbons, polymers with polymethacrylate in the main-chain significantly hinders macroscopic gelation. Morphology of the organogels was analysed by field emission scanning electron microscopy (FESEM), and mechanical strengths of the organogels were determined by rheological measurements. Reversible addition-fragmentation chain transfer (RAFT) polymerization chain transfer agents (CTA)s,[R1 —S—C=(S)—S—R2] with different —Ri and — R2 groups, have been employed to study the effect of structural variation at the chain-end on macroscopic assembly mechanism. We found that the additional interactions between terminal groups via hydrogenbonding or n-n stacking interactions or both help to build up the self-assembly pathway and thereby produces mechanically stable organogels. 展开更多
关键词 Organogelation HYDROPHOBIC interactions Poly (methacrylate/aery late) BACKBONE RAFT polymerization Self-assembly
Design and synthesis of self-included pillar[5]arene-based bis-[1]rotaxanes
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作者 Mengjun Wang Xusheng Du +5 位作者 Huasheng Tian Qiong Jia Rong Deng Yahan Cui Chunyu Wang Kamel Meguellati 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第2期345-348,共4页
Two strategies for the design of new pillar[5]arene-based mechanically self-interlocked molecules (MSMs) are reported here. The first strategy is based on the construction of an intermediate pseudo[1]rotaxane followed... Two strategies for the design of new pillar[5]arene-based mechanically self-interlocked molecules (MSMs) are reported here. The first strategy is based on the construction of an intermediate pseudo[1]rotaxane followed by the desired bis-[l]rotaxane. The other one is based on the construction of the desired bis-[1]rotaxane directly via a condensation reaction through host-guest interactions between a mono-functionalized pillar[5]arene and the axle. The newly synthesized bis-[1]rotaxane BR was characterized by 1H NMR, 13C NMR, 2D NMRs (1H-13C HSQC,1H-1H COSY and NOESY) and LC-ESI-MS,which indicated compound BR displayed an self-interlocked structure in CDCl3. Surprisingly, the results of SEM, TEM and DLS showed that the compound BR could assemble into spherical nanoparticles in MeOH. 展开更多
关键词 arene rotaxane Host-guest interactions Supramolecular architectures Self-assembly
MicroRNA-135a Modulates Hepatitis C Virus Genome Replication through Downregulation of Host Antiviral Factors
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作者 Catherine Sodroski Brianna Lowey +2 位作者 Laura Hertz T. Jake Liang Qisheng Li 《中国病毒学:英文版》 CAS CSCD 2019年第2期197-210,共14页
Cellular microRNAs(miRNAs) have been shown to modulate HCV infection via directly acting on the viral genome or indirectly through targeting the virus-associated host factors. Recently we generated a comprehensive map... Cellular microRNAs(miRNAs) have been shown to modulate HCV infection via directly acting on the viral genome or indirectly through targeting the virus-associated host factors. Recently we generated a comprehensive map of HCV–miRNA interactions through genome-wide miRNA functional screens and transcriptomics analyses. Many previously unappreciated cellular miRNAs were identified to be involved in HCV infection, including miR-135a, a human cancerrelated miRNA. In the present study, we investigated the role of miR-135a in regulating HCV life cycle and showed that it preferentially enhances viral genome replication. Bioinformatics-based integrative analyses and subsequent functional assays revealed three antiviral host factors, including receptor interacting serine/threonine kinase 2(RIPK2), myeloid differentiation primary response 88(MYD88), and C-X-C motif chemokine ligand 12(CXCL12), as bona fide targets of miR-135a. These genes have been shown to inhibit HCV infection at the RNA replication stage. Our data demonstrated that repression of key host restriction factors mediated the proviral effect of miR-135a on HCV propagation. In addition,miR-135a hepatic abundance is upregulated by HCV infection in both cultured hepatocytes and human liver, likely mediating a more favorable environment for viral replication and possibly contributing to HCV-induced liver malignancy.These results provide novel insights into HCV–host interactions and unveil molecular pathways linking miRNA biology to HCV pathogenesis. 展开更多
关键词 Hepatitis C virus (HCV) GENOME REPLICATION Virus-host interactions miR-135a ANTIVIRAL factors
植物多酚与蛋白质互作机制表征方法研究进展 预览
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作者 李春翼 田勇 +4 位作者 杨雅轩 李苇舟 赵吉春 李富华 明建 《食品与发酵工业》 CAS CSCD 北大核心 2019年第13期262-268,共7页
多酚化合物是食物中对人体健康有促进作用的功能活性成分,其功能作用的发挥与食物中其他营养成分(如蛋白质、多糖)之间的相互作用密切相关。为深入研究食品加工过程中功能营养成分的相互作用与变化,本文综述了多酚与蛋白质的相互作用机... 多酚化合物是食物中对人体健康有促进作用的功能活性成分,其功能作用的发挥与食物中其他营养成分(如蛋白质、多糖)之间的相互作用密切相关。为深入研究食品加工过程中功能营养成分的相互作用与变化,本文综述了多酚与蛋白质的相互作用机制及表征方法,包括荧光光谱法、傅里叶变换红外光谱法、拉曼光谱法、圆二色谱、等温滴定量热法、核磁共振法、原子力显微镜、激光扫描共聚焦显微镜、分子对接和分子动态模拟等。多酚与蛋白质之间的相互作用主要是氢键、疏水相互作用、静电相互作用和范德华力,应用多种表征方法可全面地解析植物多酚与蛋白质相互作用机制。 展开更多
关键词 多酚 蛋白质 相互作用 表征方法
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Systems Biology of Plant-Microbiome Interactions
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作者 Patricia A.Rodriguez Michael Rothballer +3 位作者 Soumitra Paul Chowdhury Thomas Nussbaumer Caroline Gutjahr Pascal Falter-Braun 《分子植物:英文版》 SCIE CAS CSCD 2019年第6期804-821,共18页
In natural environments,plants are exposed to diverse microbiota that they interact with in complex ways.While plant-pathogen interactions have been intensely studied to understand defense mechanisms in plants,many mi... In natural environments,plants are exposed to diverse microbiota that they interact with in complex ways.While plant-pathogen interactions have been intensely studied to understand defense mechanisms in plants,many microbes and microbial communities can have substantial beneficial effects on their plant host.Such beneficial effects include improved acquisition of nutrients,accelerated growth,resilience against pathogens,and improved resistance against abiotic stress conditions such as heat,drought,and salinity.However,the beneficial effects of bacterial strains or consortia on their host are often cultivar and species specific,posing an obstacle to their general application.Remarkably,many of the signals that trigger plant immune responses are molecularly highly similar and often identical in pathogenic and beneficial microbes.Thus,it is unclear what determines the outcome of a particular microbe-host interaction and which factors enable plants to distinguish beneficials from pathogens.To unravel the complex network of genetic,microbial,and metabolic interactions,including the signaling events mediating microbe-host interactions,comprehensive quantitative systems biology approaches will be needed. 展开更多
关键词 PLANT systems biology PLANT MICROBIOME microbial COMMUNITIES SynComs microbe-host INTERACTIONS
竞争型非线性介质中艾里-高斯光束交互作用的调控 预览
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作者 陈卫军 宋德 +3 位作者 李野 王新 秦旭磊 刘春阳 《物理学报》 SCIE EI CAS CSCD 北大核心 2019年第9期164-171,共8页
基于分步傅里叶法研究了艾里-高斯光束在三次聚焦和五次散焦竞争型非线性介质中交互作用的调控.结果表明:当入射角度为零时,同相位艾里-高斯光束相互吸引,五次散焦非线性强度较弱时,可形成周期逐渐缩短的呼吸孤子或强度不变的孤子.五次... 基于分步傅里叶法研究了艾里-高斯光束在三次聚焦和五次散焦竞争型非线性介质中交互作用的调控.结果表明:当入射角度为零时,同相位艾里-高斯光束相互吸引,五次散焦非线性强度较弱时,可形成周期逐渐缩短的呼吸孤子或强度不变的孤子.五次散焦非线性强度较强时,呼吸孤子的平均宽度变大甚至出现光束分叉现象,形成孤子对.反相位艾里-高斯光束相互排斥,排斥力随五次散焦非线性强度单调递增.当入射角度不为零时,通过控制光束入射角度的正负和初始间距.同相位和反相位艾里-高斯光束交互作用时可以同时表现出相互吸引和排斥的现象. 展开更多
关键词 竞争型非线性 艾里-高斯光束 交互作用 光场调控
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微藻-细菌共生体系在废水处理中的应用
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作者 皮永蕊 吕永红 +3 位作者 柳莹 唐永政 高丽 包木太 《微生物学报》 CAS CSCD 北大核心 2019年第6期1188-1196,共9页
在微藻-细菌协同共生的过程中,藻类光合作用释放的氧气被异养微生物利用来矿化水体中的污染物,细菌呼吸为藻类提供二氧化碳作为碳源。近年来,藻类-细菌协同共生体系在污水处理中的应用得到了广泛的研究。本文重点综述了菌藻协同共生体... 在微藻-细菌协同共生的过程中,藻类光合作用释放的氧气被异养微生物利用来矿化水体中的污染物,细菌呼吸为藻类提供二氧化碳作为碳源。近年来,藻类-细菌协同共生体系在污水处理中的应用得到了广泛的研究。本文重点综述了菌藻协同共生体系中微藻与细菌之间的三种相互作用,以及菌藻协同共生体系在废水处理中的应用。菌藻协同共生体系中的微藻与细菌通过营养交换、信号转导及基因转移等相互作用实现共赢。该体系广泛用于处理富营养化、重金属、药物、多环芳烃(polycyclic aromatic hydrocarbons,PAHs)、石油烃化合物等难降解的有机污染的水体。对于氮、磷等营养物质的去除,其主要机理涉及同化作用、厌氧氨氧化作用、硝化与反硝化作用、磷酸化作用等。对重金属、药物、石油烃化合物及其他有机化合物的去除机制主要是生物吸附、生物富集及细胞内外的生物降解。 展开更多
关键词 微藻-细菌 相互作用 营养物 重金属 药物污染物 石油烃
Ring current proton scattering by low-frequency magnetosonic waves 预览
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作者 Jiang Yu Jing Wang Jun Cui 《地球与行星物理:英文版》 CSCD 2019年第4期365-372,共8页
Magnetosonic (MS) waves are believed to have the ability to affect the dynamics of ring current protons both inside and outside the plasmasphere. However, previous studies have focused primarily on the effect of high-... Magnetosonic (MS) waves are believed to have the ability to affect the dynamics of ring current protons both inside and outside the plasmasphere. However, previous studies have focused primarily on the effect of high-frequency MS waves (f > 20 Hz) on ring current protons. In this study, we investigate interactions between ring current protons and low-frequency MS waves (< 20 Hz) inside the plasmasphere. We find that low-frequency MS waves can effectively accelerate < 20 keV ring current protons on time scales from several hours to a day, and their scattering efficiency is comparable to that due to high-frequency MS waves (>20 Hz), from which we infer that omitting the effect of low-frequency MS waves will considerably underestimate proton depletion at middle pitch angles and proton enhancement at large pitch angles. Therefore, ring current proton modeling should take into account the effects of both low- and highfrequency MS waves. 展开更多
关键词 magnetosonic WAVES ring current PROTONS wave-particle INTERACTIONS PROTON distribution EVOLUTIONS
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Recent progress and challenges in screening and characterization of UGT1A1 inhibitors
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作者 Xia Lv Yangliu Xia +3 位作者 Moshe Finel Jingjing Wu Guangbo Ge Ling Yang 《药学学报:英文版》 CSCD 2019年第2期258-278,共21页
Uridine-diphosphate glucuronosyltransferase 1 A1(UGT1 A1) is an important conjugative enzyme in mammals that is responsible for the conjugation and detoxification of both endogenous and xenobiotic compounds. Strong in... Uridine-diphosphate glucuronosyltransferase 1 A1(UGT1 A1) is an important conjugative enzyme in mammals that is responsible for the conjugation and detoxification of both endogenous and xenobiotic compounds. Strong inhibition of UGT1 A1 may trigger adverse drug/herb–drug interactions, or result in metabolic disorders of endobiotic metabolism. Therefore, both the US Food and Drug Administration(FDA)and the European Medicines Agency(EMA) have recommended assaying the inhibitory potential of drugs under development on the human UGT1 A1 prior to approval. This review focuses on the significance,progress and challenges in discovery and characterization of UGT1 A1 inhibitors. Recent advances in the development of UGT1 A1 probes and their application for screening UGT1 A1 inhibitors are summarized and discussed in this review for the first time. Furthermore, a long list of UGT1 A1 inhibitors, including information on their inhibition potency, inhibition mode, and affinity, has been prepared and analyzed. Challenges and future directions in this field are highlighted in the final section. The information and knowledge that are presented in this review provide guidance for rational use of drugs/herbs in order to avoid the occurrence of adverse effects via UGT1 A1 inhibition, as well as presenting methods for rapid screening and characterization of UGT1 A1 inhibitors and for facilitating investigations on UGT1 A1–ligand interactions. 展开更多
关键词 UGT1A1 INHIBITORS Drug/herbdrug INTERACTIONS Probe SUBSTRATES HIGH-THROUGHPUT SCREENING
Dipole-dipole interactions enhance non-Markovianity and protect information against dissipation
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作者 Munsif Jan 许小冶 +4 位作者 王琴琴 陈哲 韩永建 李传锋 郭光灿 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第9期100-106,共7页
Preserving non-Markovianity and quantum entanglement from decoherence effect is of theoretical and practical significance in the quantum information processing technologies.In this context, we study a system S that is... Preserving non-Markovianity and quantum entanglement from decoherence effect is of theoretical and practical significance in the quantum information processing technologies.In this context, we study a system S that is initially correlated with an ancilla A, which interacts with the environment E via an amplitude damping channel.We also consider dipole-dipole interactions(DDIs) between the system and ancilla, which are responsible for strong correlations.We investigate the impact of DDIs and detuning on the non-Markovianity and information exchange in different environments.We show that DDIs are not only better than detuning at protecting the information(without destroying the memory effect) but also induce memory by causing a transition from Markovian to non-Markovian dynamics.In contrast, although detuning also protects the information, it causes a transition from non-Markovian to the Markovian dynamics.In addition, we demonstrate that the non-Markovianity grows with increasing DDI strength and diminishes with increasing detuning.We also show that the effects of negative detuning and DDIs can cancel out each other, causing a certain loss of coherence and information. 展开更多
关键词 DECOHERENCE non-Markovianity dipole-dipole interactions ENTANGLEMENT
Interaction of diabatic processes, large-scale eddies and the mean atmospheric circulation over the Atlantic, Arctic and Eurasia 预览
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作者 Ralf JAISER Dorthe HANDORF Klaus DETHLOFF 《极地科学进展:英文版》 CSCD 2019年第2期81-92,共12页
In the last decade, the atmospheric part of the climate system experienced a shift from pronounced zonal to stronger meridional flow configurations and regionally diverse changes and trends. The climate system shows c... In the last decade, the atmospheric part of the climate system experienced a shift from pronounced zonal to stronger meridional flow configurations and regionally diverse changes and trends. The climate system shows complex interactions and nonlinear behavior, manifested in global warming, rising ocean temperatures and the retreat of Arctic sea ice. Although atmospheric trends and changes are observed, underlying processes are not well understood. In this study we diagnose the interaction of large-scale atmospheric eddies and the mean flow with respect to diabatic heating and cooling processes that impact on the atmospheric advection of heat. For this purpose, three-dimensional Eliassen-Palm flux theory is used in combination with an analysis of the thermodynamic equation, diabatic heating and cooling and heat advection. The most recent decades of observed winter climate are evaluated in terms of climatology and trends over the Atlantic, Arctic and Eurasia. The change of the atmospheric circulation and related processes differ between early and late winter. In early winter, the interaction of macro-turbulent eddies with the mean flow is inhibited at the Atlantic jet stream entrance region and atmospheric heat is meridionally advected into the Arctic, both related to strong high pressure anomalies. In late winter, these anomalies are inverted and a negative phase of the Arctic Oscillation with a more wavy mean flow and a tendency towards stronger meridionalization is observed. 展开更多
关键词 diabatic heating heat advection wave-mean flow interactions North ATLANTIC OSCILLATION ARCTIC OSCILLATION sea ice climate change ARCTIC Amplification polar-mid-latitude linkages
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Drug interactions of dipeptidyl peptidase 4 inhibitors involving CYP enzymes and P-gp efflux pump 预览
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作者 Naina Mohamed Pakkir Maideen 《世界荟萃分析杂志》 2019年第4期156-161,共6页
Dipeptidyl peptidase 4 (DPP4) inhibitors are oral antidiabetic drugs approved to manage type 2 diabetes mellitus. Saxagliptin is a substrate of CYP3A4/5 enzymes while other DPP4 inhibitors such as sitagliptin, linagli... Dipeptidyl peptidase 4 (DPP4) inhibitors are oral antidiabetic drugs approved to manage type 2 diabetes mellitus. Saxagliptin is a substrate of CYP3A4/5 enzymes while other DPP4 inhibitors such as sitagliptin, linagliptin, gemigliptin and teneligliptin are weak substrates of CYP3A4. DPP4 inhibitors have also been identified as substrates of P-gp. Hence, the drugs inhibiting or inducing CYP3A4/5 enzymes and/or P-gp can alter the pharmacokinetics of DPP4 inhibitors. This review is aimed to identify the drugs interacting with DPP4 inhibitors. The plasma concentrations of saxagliptin have been reported to be increased significantly by the concomitant administration of ketoconazole or diltiazem while no significant interactions between various DPP4 inhibitors and drugs like warfarin, digoxin or cyclosporine have been identified. 展开更多
关键词 Drug interactions SITAGLIPTIN SAXAGLIPTIN LINAGLIPTIN Gemigliptin Teneligliptin VILDAGLIPTIN Anagliptin CYP3A4 P-GP EFFLUX pump
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离子强度对胶原与4-硫酸软骨素间相互作用的影响(续)
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作者 田荟琳 刘国兴 李国英 《中国皮革》 CAS 2019年第6期17-23,37共8页
胶原与硫酸较骨素(CS)间相互作用力的研究具有重要的生理意义和病理意义,采用差示扫描量热法(DSC)和二维红外分析(2D1R)研究离子强度对胶原与4-硫酸软骨素(CSA)间相互作用力的影响。DSC结果表明:相同胶原/CSA质量比下,共混物热稳定性随... 胶原与硫酸较骨素(CS)间相互作用力的研究具有重要的生理意义和病理意义,采用差示扫描量热法(DSC)和二维红外分析(2D1R)研究离子强度对胶原与4-硫酸软骨素(CSA)间相互作用力的影响。DSC结果表明:相同胶原/CSA质量比下,共混物热稳定性随着离子强度的增加而降低;相同离子强度下,共混物热稳定性随着CSA量的增加而增强.2DIR结果表明:CSA含量小于50%时,离子强度影响胶原与CSA间相互作用的强度和种类;离子强度为0.2mol/kg时,胶原分子与CSA间存在氢键作用和静电相互作用;进一步增加离子强度,胶原分子带正电荷的基团与CSA离子化的硫酸根基团和竣酸根基团间的静电作用消失,仅存在胶原分子与CSA间的氢键作用。CSA含量大于50%时,离子强度仅影响胶原分子与CSA间相互作用的强度;离子强度增至0.3~0.4mol/kg时,胶原分子与CSA间均存在静电作用及氢键作用。随着溶液离子强度的增加,胶原与CSA间相互作用的强度均随之减弱。 展开更多
关键词 胶原 4-硫酸软骨素 相互作用 二维红外相关分析 离子强度
沥青质分子聚集体的聚集内因 预览
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作者 蔡新恒 龙军 +4 位作者 任强 董明 王威 田松柏 刘泽龙 《石油学报(石油加工)》 EI CAS CSCD 北大核心 2019年第5期920-928,共9页
运用量子力学、分子动力学等方法,研究沥青质分子聚集体形成过程的分子构型变化、能量变化以及电子分布情况。结果表明:沥青质分子形成聚集体过程中形变能很小,沥青质分子发生形变不是沥青质聚集体形成的决定因素,但为沥青质分子聚集进... 运用量子力学、分子动力学等方法,研究沥青质分子聚集体形成过程的分子构型变化、能量变化以及电子分布情况。结果表明:沥青质分子形成聚集体过程中形变能很小,沥青质分子发生形变不是沥青质聚集体形成的决定因素,但为沥青质分子聚集进而形成聚集体提供基础,沥青质分子具有很强的本征聚集活性;沥青质分子间相互作用能很大,是沥青质分子聚集体形成的决定因素,其中,属于分子间固有属性的范德华力及泡利排斥作用之和相对较小,与沥青质分子结构特征相关的π-π相互作用及氢键作用之和很大,表明由沥青质分子的大芳环体系和多杂原子的结构特征引起的π-π相互作用及氢键作用是导致形成沥青质分子聚集体的主要原因;在所研究体系中,金属卟啉分子与含吡啶氮的沥青质分子通过π-π相互作用而非轴向配位作用形成聚集体。 展开更多
关键词 沥青质 分子聚集体 分子模拟 Π-Π作用 氢键
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Phosphorous-Modified Carbon Nanotube-Supported Pt Nanoparticles for Propane Dehydrogenation Reaction 预览
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作者 Liu Jie Liu Changcheng +1 位作者 Da Zhijian Zheng Huidong 《中国炼油与石油化工:英文版》 SCIE CAS 2019年第1期7-14,共8页
The sintering of Pt nanoparticles is one of the main reasons for catalyst deactivation during the high-temperature propane dehydrogenation(PDH) reaction. Promoters and supports have been introduced to prolong the cata... The sintering of Pt nanoparticles is one of the main reasons for catalyst deactivation during the high-temperature propane dehydrogenation(PDH) reaction. Promoters and supports have been introduced to prolong the catalyst life.However, it is still necessary to develop novel catalysts with robust stability. Herein, the phosphorus-modified carbon nanotube-supported Pt nanoparticles were employed for the PDH process. Phosphorus modification improves the Pt dispersion, effectively promoting the activity of Pt/P-CNTs. Additionally, the phosphorus-modified CNTs can interact strongly with Pt nanoparticles by improving the electron transfer or hybridization, stabilizing Pt nanoparticles from agglomeration, and significantly enhancing the catalyst stability. 展开更多
关键词 PROPANE DEHYDROGENATION phosphorus-modified carbon NANOTUBES PLATINUM catalyst strong metal-support interactions
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Turbulence and suspended sediment processes in the Garonne Rivertidal bore in November 2016 预览
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作者 David Reungoat Xinqian Leng Hubert Chanson 《国际泥沙研究:英文版》 SCIE 2019年第5期496-508,共13页
A tidal bore is a water discontinuity at the leading edge of a ood tide wave in estuaries with a large tidal range and funneling topography. New measurements were done in the Garonne River tidal bore on 14 15 November... A tidal bore is a water discontinuity at the leading edge of a ood tide wave in estuaries with a large tidal range and funneling topography. New measurements were done in the Garonne River tidal bore on 14 15 November 2016, at a site previously investigated between 2010 and 2015. The data focused on long, continuous, high-frequency records of instantaneous velocity and suspended sediment con- centration (SSC) estimate for several hours during the late ebb, tidal bore passage and ood tide. The bore passage drastically modi ed the ow eld, with very intense turbulent and sediment mixing. This was evidenced with large and rapid uctuations of both velocity and Reynolds stress, as well as large SSCs during the ood tide. Granulometry data indicated larger grain sizes of suspended sediment in water samples compared to sediment bed material, with a broader distribution, shortly after the tidal bore. The tidal bore induced a sudden suspended sediment ux reversal and a large increase in suspended sedi- ment ux magnitude. The time-variations of turbulent velocity and suspended sediment properties indicated large uctuations throughout the entire data set. The ratio of integral time scales of SSC to velocity in the x-direction was on average TE,SSC/TE,x 0.16 during the late ebb tide, compared to TE,SSC/ TE,x 0.09 during the late ood tide. The results imply different time scales between turbulent velocities and suspended sediment concentrations. 展开更多
关键词 TIDAL BORE Garonne RIVER HYDRODYNAMICS Suspended SEDIMENT Field observations Turbulence-sediment suspension interactions
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Measuring relic abundance of minimal dark matter at hadron colliders
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作者 QingHong Cao Ti Gong +1 位作者 KePan Xie Zhen Zhang 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第8期55-74,共20页
We consider the special case that the dark matter(DM) candidate is not detected in direct-detection programs when the experimental sensitivity reaches the neutrino flux background.In such circumstance the DM searches ... We consider the special case that the dark matter(DM) candidate is not detected in direct-detection programs when the experimental sensitivity reaches the neutrino flux background.In such circumstance the DM searches at the colliders impose constraints on the DM relic abundance if the DM candidate is a WIMPs type.Specifically,we consider the triplet(quintet and septet) DMs in the framework of minimal DM model and explore the potential of discovering the DM candidate in the mono-jet,mono-photon and vector boson fusion channels at the Large Hadron Collider(LHC) and future 100 TeV hadron collider.If the DM candidate in such a scenario is discovered at the LHC,then additional DM candidates are needed to explain the observed relic abundance.On the other hand,null results in those DM searching programs at the colliders give rise to lower limits of DM relic abundance. 展开更多
关键词 DARK matter electro WEAK interactions HADRON COLLIDERS
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