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Microbial and heavy metal contamination in commonly consumed traditional Chinese herbal medicines

Journal of Traditional Chinese Medicine 2013年第1期33卷 119-124页

作者： Adelinesuyien Ting Yiingyng Chow weishang tan School of Science Monash University Sunway Campus Jalan Lagoon Selatan Bandar Sunway 46150 Petaling Jaya Selangor Malaysia

OBJECTIVE： The increasing popularity and widespread use of traditional Chinese herbs as alterna- tive medicine have sparked an interest in understanding their biosafety, especially in decoctions that are consumed. This study aimed to assess the level of microbial and heavy metal contamination in commonly consumed herbal medicine in Malay- sia and the effects of boiling on these contamination levels. METHODS： Four commonly consumed Chinese herbal medicine in Malaysia-＂Eight Treasure Herbal Tea＂, ＂Herbal Tea＂, Xiyangshen （Radix panacis Quin- quefolii） and Dangshen （Radix Codonopsis） were evaluated in this study. Herbal medicines were pre- pared as boiled and non-boiled decoctions, and their microbial enumeration and heavy metal detection were conducted with plate assay and atom- ic absorption spectroscopy, respectively. RESULTS： Findings revealed that herbal medicines generally had 6 Iogl0cfu/mL microbial cells and that boiling had significantly reduced microbial contaminants, where no Bacillus spp., Staphylococcus spp. and Clostridium spp. were recovered. Heavy metals such as Mn, Cu, Cd, pb, Fe and Zn were also detect- ed from all the samples, generally in low concentra- tions （〈1 mg/L） except for Mn （18.545 mg/L）. All de- coctions （after boiling） have reduced concentra- tions of Cu, while others were not significantly dif- ferent. Comparisons between samples with single and multi-herbs suggest level of microbial and metal contamination is not influenced by number of herbs in sample. CONCLUSION： Herbal medicines generally have microbial and heavy metal contaminants. However, the boiling process to generate decoctions was able to successfully reduce the number of microbes and Cu, ensuring safety of herbal medicines for consumption.

关键词： Decoction processing Drug contamination Heavy metal poisoning, nervous system Microbial consortia Drugs, Chinese herbal

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Finite Element Analysis on the Uniaxial Compressive Behavior of Concrete with Large-Size Recycled Coarse Aggregate

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Journal of Renewable Materials 2022年第3期10卷 699-720页

作者： tan Li Jianzhuang Xiao Amardeep Singh Department of Structural Engineering Tongji UniversityShanghai200092China

To model the concrete with complex internal structure of concrete with large sized aggregates the effect of internal structure on uniaxial compression behavior are ***-sized recycled aggregates behave differently in the concrete *** understand the influence on concrete matrix,a finite element model was developed to model recycled aggregate concrete composed of multiple randomly distributed irregular aggregates and cement *** model was used to calculate the effect of large-size recycled coarse aggregate(LRCA)on the strength of recycled aggregate concrete and simulate the compressive strength of cubes and *** factors such as the strength of new concrete,the strength of old concrete,the defective element content,the shape of LRCA,the incorporation ratio of LRCA and the size of LRCA that can affect the strength of concrete are analyzed in this *** showed that the influence of various factors on concrete strength are in the following desend-ing order:(i)strength of newly poured concrete;(ii)original strength of recycled aggregates;and(iii)*** can be seen that the cracking of the phase material elements starts along the bonding zones between gravel and mortar or the new and old mortar,then spreads to mortar and finally to *** cracking tendency is most significant in LRCA,which means that the fracturing is related to the fracture of the *** evaluating the variations in strength and quality of the recycled concrete,the influences on concrete strength and quality were *** results showed that the proposed concrete model with LRCA was successfully applied to studying the uniaxial compressive behavior of concrete with large-size recycled coarse aggregate.

关键词： Recycled aggregate concrete(RAC) large-size recycled coarse aggregates(LRCA) finite element simulation strength cracking

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Limit analysis of extended reach drilling in South China Sea

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petroleum Science 2009年第2期6卷 166-171页

作者： Gao Deli tan Chengjin tang Haixiong MOE Key Laboratory of petroleum Engineering China University of Petroleum Beijing 102249 China CNOOC China Limited-Shenzhen Shenzhen Guangdong 518067 China

Extended reach wells （ERws）, especially horizontal extended reach well with a high HD （horizontal displacement） to TVD （true vertical depth） ratio, represent a frontier technology and challenge the drilling limitations. Oil and gas reservoir in beaches or lakes and offshore can be effectively exploited by using extended reach drilling （ERD） technology. This paper focuses on the difficult technological problems encountered during exploiting the Liuhua 11-1 oil field in the South China Sea, China. Emphasis is on investigating the key subjects including prediction and control of open hole limit extension in offshore ERD, prediction of casing wear and its prevention and torque reduction, φ244.5mm casing running with floating collars to control drag force, and steerable drilling modes. The basic concept of limit extension in ERD is presented and the prediction method for open hole limit extension is given in this paper. A set of advanced drilling mechanics and control technology has been established and its practical results are verified by field cases. All those efforts may be significant for further investigating and practicing ERD limit theory and control technology in the future.

关键词： Extended reach drilling deep-water drilling limit analysis downhole tubular mechanics,drag and torque wellbore instability

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Linear polymer aqueous solutions in soft lubrication:From boundary to mixed lubrication

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Science China(Technological Sciences) 2013年第7期56卷 1709-1714页

作者： LIU ShuHai tan GuiBin wANG DeGuo College of Mechanical and Transportation Engineering China University of Petroleum-Beijing

In order to better understand linear polymer aqueous solutions in soft lubrication from boundary to mixed lubrication,poly(ethylene glycol) and sodium hyaluronateare used as model polymers were investigated by using UMT-2 tribometer with the ball-on-disk mode. The relationship between the master Stribeck curves of the polymer aqueous solutions and the influence factors were investigated. Experimental results indicated that soft lubrication is determined by lubricant rheological properties and surface-lubricant interactions, e.g., wetting behavior of polymer aqueous solution on tribological surfaces.

关键词： soft contact lubrication linear polymer aqueous solutions mixed lubrication boundary lubrication

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poisson-Boltzmann Solvents in Molecular Dynamics Simulations

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Communications in Computational physics 2008年第5期3卷 1010-1031页

作者： Jun wang Chunhu tan Yu-Hong tan Qiang Lu Ray Luo Department of Molecular Biology and Biochemistry University of California IrvineCA 92697-3900USA.

Recent years have witnessed significant improvement in implicit solvents based on the poisson-Boltzmann theory,whether in the forms of numerical solution or analytical *** worth noting are the improvements and revisions of those implicit solvents for stable dynamics *** these technical advancements,attentions are now.p.id to the quality of implicit solvents as compared with the more expensive explicit *** new developments in nonpolar solvents mentioned above and reviewed elsewhere will also result in more accurate simulations of *** have also touched the new challenges facing the implicit *** is how to incorporate these solvents in the emerging polarizable force *** challenges could also arise from the assumptions underlying all implicit solvents,as recently explored to couple electrostatic and nonelectrostatic components *** addition,hybrid solvents could eventually become a reality for dynamics simulation even this has been proposed in the early days of computational *** is likely that such hybrid solvents will offer the necessary accuracy,as they no longer average out the very degrees of freedom that are of interest in studies where solute/solvent coupling is crucial.

关键词： poisson-Boltzmann equation implicit solvent molecular dynamics proteins

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县域职业教育推动乡村振兴的行动逻辑、发展审思与实践路径

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职教通讯 2024年第7期 46-53页

作者：连会斌谭广兴上海开放大学金山分校山东水利职业学院水利工程系

县域职业教育在乡村建设中责任重大,其行动逻辑在于实现职业教育和乡村振兴之间的双向赋能,通过本土村落的文化彰显与乡韵塑型挖掘乡村地区的潜能,基于乡村振兴的人才回流与迭代培养解决乡村振兴的核心问题。县域职业教育未来需要将发... 详细信息

县域职业教育在乡村建设中责任重大,其行动逻辑在于实现职业教育和乡村振兴之间的双向赋能,通过本土村落的文化彰显与乡韵塑型挖掘乡村地区的潜能,基于乡村振兴的人才回流与迭代培养解决乡村振兴的核心问题。县域职业教育未来需要将发展重心转移,把握以培训为发展导向的历史契机与时代定位;将话语体系筑实,深度扎根乡村进行塑型重构并追寻行之有效的范式;实现自身治理能力内生,充分运用政策关怀与实力跃升,彰显类型底色。运用县域职业教育推动乡村振兴的实践路径在于干部人才培养的有序化与规范化、实用技能送教的现实化与持续化、特色文化振兴的针对化与可视化。

关键词：县域职业教育乡村振兴行动逻辑发展审思实践路径

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The application of C–H bond functionalization in the total syntheses of indole natural products

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Organic Chemistry Frontiers 2022年第4期9卷 1195-1210页

作者： Dong-Xing tan Fu-She Han CAS Key Lab of High-performance Synthetic Rubber and its Composite Materials Changchun Institute of Applied ChemistryChinese Academy of Sciences5625 Renmin StreetChangchunJilin 130022China

The direct functionalization of unactivated C–H bonds has been a rapidly growing field in organic chem-istry in recent years because of its indisputable advantages in bond forming reactions in terms of step and atom-... 详细信息

关键词： functionalization bonds bond

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两种草本植物对红黏土边坡的固土护坡效应

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水土保持通报 2024年第2期44卷 146-154页

作者：王连锐严亚商崇菊谭娟杨永宇贵州省水利科学研究院贵州贵阳550002 贵州省油气勘查开发工程研究院贵州贵阳550081

[目的]探讨两种草本植物对红黏土边坡的固土护坡效应,为该类型边坡、河道、大坝的生态治理提供科学参考。[方法]以红黏土边坡为研究对象,选取狗牙根和香根草作为护坡植物,通过种植试验、根系拉伸试验、直剪试验、室内模拟冲刷试验,探讨... 详细信息

[目的]探讨两种草本植物对红黏土边坡的固土护坡效应,为该类型边坡、河道、大坝的生态治理提供科学参考。[方法]以红黏土边坡为研究对象,选取狗牙根和香根草作为护坡植物,通过种植试验、根系拉伸试验、直剪试验、室内模拟冲刷试验,探讨两种草本植物的护坡效应。[结果]①种植150 d内,两种草本植物均稳定生长,根系抗拉强度持续增加;生长30~150 d,狗牙根的最大抗拉力从0.84 N增至8.59 N,香根草的最大抗拉力从4.78 N增至89.89 N。②生长120 d时,对比无根土,狗牙根根土复合体的黏聚力提升91.1%,内摩擦角提升12.45%;香根草根土复合体的黏聚力提升107.47%,内摩擦角提升12.74%。③生长150 d时,对比裸坡,狗牙根坡的径流速率降低45.02%~54.15%,产沙速率降低58.3%~93.85%,60 min累计产沙量降低81.02%;香根草坡的径流速率降低35.46%~46.48%,产沙速率降低46.8%~89.44%,60 min累计产沙量降低74.61%。[结论]两种草本植物对红黏土边坡都具有良好的固土护坡效应,香根草对土体抗剪强度的增益效果更明显,狗牙根的水土保持效果更显著。

关键词：红黏土植物护坡根系抗拉力抗剪强度水土保持

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鱼尼丁受体及以其为靶标的杀虫剂

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生物灾害科学 2024年第3期47卷 347-363页

作者：谭海军李贤贤苏州艾科尔化工科技有限公司江苏昆山215300 山东惠民中联生物科技有限公司山东济南251600

作为最大的离子通道受体蛋白,鱼尼丁受体(Ry R)主要介导生物体胞内钙离子(Ca^(2+))释放而对肌肉兴奋-收缩耦联等生命活动起关键作用。由于在昆虫和脊椎动物体内存在显著差异,Ry R成为现代杀虫剂研发的理想靶标。由此开发的以氟苯虫酰胺... 详细信息

作为最大的离子通道受体蛋白,鱼尼丁受体(Ry R)主要介导生物体胞内钙离子(Ca^(2+))释放而对肌肉兴奋-收缩耦联等生命活动起关键作用。由于在昆虫和脊椎动物体内存在显著差异,Ry R成为现代杀虫剂研发的理想靶标。由此开发的以氟苯虫酰胺和氯虫苯甲酰胺为代表的双酰胺类杀虫剂也成为最重要的杀虫剂品类之一。对Ry R及其Ca^(2+)释放通道的结构和功能进行介绍,并对以Ry R为靶标的杀虫剂(主要是双酰胺类杀虫剂)的研发背景与现状、化学合成、作用机制、生物活性、安全性、抗性、制剂及应用等进行总结,旨在为该类杀虫剂的研究、开发和应用提供指导。

关键词：鱼尼丁受体双酰胺类杀虫剂化学合成作用机制生物活性抗性

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激光增材制造网状结构金属基复合材料的研究进展

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中国有色金属学报 2024年第4期34卷 1052-1070页

作者：伍子纯刘阳李海尊谭振国唐楠宋宇峰刘筱陈宇强湖南科技大学机电工程学院湘潭411201 湖南科技大学高功效轻合金构件成形技术及耐损伤性能评价湖南省工程研究中心湘潭411201 湖南西交智造科技有限公司湘潭411100

相较于传统增强相呈均匀分布的金属基复合材料,网状结构金属基复合材料因其独特的“机械互锁”“位错钉扎”等组织结构特征,具有更优异的室温强度、高温强度、弹性模量和断裂韧性,在航天、航空等领域上具有广泛的应用前景。激光增材制... 详细信息

相较于传统增强相呈均匀分布的金属基复合材料,网状结构金属基复合材料因其独特的“机械互锁”“位错钉扎”等组织结构特征,具有更优异的室温强度、高温强度、弹性模量和断裂韧性,在航天、航空等领域上具有广泛的应用前景。激光增材制造技术可实现对网状结构的精细化调控,为网状结构金属基复合材料的进一步发展提供了新的途径。本文综述了高能量激光束诱导马兰戈尼对流作用下网状结构金属基复合材料的形成机理、影响网状结构形成的因素、不同类型网状结构的显微组织结构特征,分析了网状结构金属基复合材料的多段弯曲断裂、微孔聚集断裂等断裂机制,阐述了在霍尔−佩奇、奥罗万、泰勒、载荷传递等强化机制共同作用下的强化机理,以及独特的增强相贫、富区协同作用下的韧化机理,并对其未来的研究方向进行了展望。

关键词：网状结构激光增材制造金属基复合材料断裂机制强韧化机理

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