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Poly.aprolactone (PCL) Chains Grafting on the Surface of Cellulose Nanocry.tals (CNCs) during <i>In Situ</i>Poly.erization of <i>ε</i>-Caprolactone at Room Temperature

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Materials Sciences and Applications 2020年第11期11卷 744-756页

作者： Jérémy.Astruc Patrice Cousin gaétan Laroche Mathieu Robert saïd Elkoun Center of Innovative Technology.and Eco-design (CITE) University of Sherbrooke Granby QC Canada Laboratoire d’Ingénierie de Surface Département de Génie des Mines de la Métallurgie et des Matériaux Centre de recherche sur les Matériaux avancés Pavillon Adrien-Pouliot University of Laval Québec QC Canada Centre de Recherche du CHU de Québec Hopital Saint-Francois d’Assise Québec QC Canada

This work aimed at investigating the feasibility.of surface modification of cellulose nanocry.tals (CNCs) using in situ ring opening poly.erization of ε-caprolactone (ε-CL) at room temperature. Residues of flax and milkweed (Asclepias sy.iaca) stem fibers were used as a source of cellulose to obtain and isolate CNCs. The cationic ring opening poly.erization (CROP) of the monomer ε-CL was used to covalently.graft poly.aprolactone (PCL) chains at the CNCs surface. Silver hexafluoroantimonate (AgSbF6) was used in combination with the extracted CNCs to initiate, at room temperature, the poly.erization and the grafting reactions with no other stimulus. fourier-Transform InfraRed (FTIR), X-ray.Photoelectron Spectrometry.(XPS), UV/visible absorption and Gel Permeation Chromatography.(GPC) analy.es evidenced the presence of PCL chains covalently.grafted at CNCs surface, the formation of Ag(0) particles as well as low or moderate molecular weight free PCL chains.

关键词： Cellulose Nanocry.tals (CNCs) Simultaneous Poly.erization and Surface Grafting ε-Caprolactone Cationic Ring Opening Poly.erization Room Temperature Silver Hexafluoroantimonate

Phy.ochemical Analy.is and Contractile Effects of Aqueous and Hy.roethanolic Extracts of Anastatica hierochuntica L. (Brassicaceae) on the Isolated Uterus of Mice

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Pharmacology.& Pharmacy 2023年第8期14卷 252-270页

作者： Belem-Kabré Wendkouni Leila Marie Esther Nitiéma Mathieu Odjo Blondine saïdath Maman Noura Oumarou y.ro Boubacar Kaboré Boukaré Somda gaëtan donzéo Traoré Tata Kadiatou Koala Moumouni Ilboudo Sy.vain Ouédraogo Moussa Kabré Elie Ouédraogo Noufou Laboratoire de Recherche-développement de Phy.omédicaments et Médicaments (LR-d/PM) Institut de Recherche en Sciences de la Santé (IRSS/CNRST) Ouagadougou Burkina Faso Laboratoire du développement du Médicament (LAdME)/Centre de formation de Recherche et d’Expertises en Sciences du Médicament (CEA-CFOREM) Université Joseph KI-ZERBO Ouagadougou Burkina Faso Laboratoire de Chimie Organique et de Phy.ique Appliquée (LCOPA) Université Joseph KI-ZERBO Ouagadougou Burkina Faso Agence Nationale pour la Sécurité sanitaire de l’Environnement de l’Alimentation du Travail et des Produits de Santé (ANSSEAT) Ouagadougou Burkina Faso

Background: Anastatica hierochuntica L. (Brassicaceae) has been claimed to treat various conditions, including complicated childbirth. The principal objective of this research was to provide scientific evidence on the contractile effect of the aqueous and hy.roethanolic extracts of the whole plant from A. hierochuntica during labor. Method: Qualitative and quantitative methods helped identify.and quantify.the phy.oconstituents in both extracts. The antioxidant activity.was studied using four standard methods (ABTS, dPPH, FRAP, and LPO). Results: The inhibitory.power of the extracts on pro-inflammatory.enzy.es such as 15-lipoxy.enase and phospholipase A2 was determined. The contractile effects of the extracts were evaluated using isolated pregnant mice uteri. Steroids, triterpenoids, flavonoids, tannins, coumarins, and reduced compounds were identified in both extracts. The hy.roethanolic extract exhibited higher content of hy.roly.able tannins (15.07 ± 0.24 mg tannic acid equivalent/g) than the aqueous decoction (11.8 ± 0.69 mg TAE/g). The extracts demonstrated the ability.to scavenge dPPH and ABTS radicals, reduce ferric ions, and inhibit especially.lipid peroxidation. No significant difference was noted in the phospholipase inhibition between the extracts and betamethasone. The hy.roethanolic extract display.d the most significant anti-lipoxy.enase activity.with an IC50 value of 55.82 ± 1.15 μg/mL. The lethal dose (Ld50) of extracts was estimated to be superior to 2000 mg/kg body.weight (bw). The ability.of the samples to produce one cm amplitude of contraction at 50% effective concentrations (EC50) was 5.33 × 10−8 ± 0.32 mg/mL for oxy.ocin, 1.51 ± 0.08 mg/mL for aqueous extract and 3.57 ± 0.61 mg/mL for hy.roethanolic extract. Conclusion: These findings could provide evidence for using Anastatica hierochuntica to facilitate childbirth.

关键词： Anastatica hierochuntica Phy.oconstituents Antioxidant Anti-Inflammatory Uterine Contractility

改性BiVO4及其光降解水中有机污染物的研究进展

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应用化工 2021年第1期50卷 210-216页

作者：赵智敏王奖萨嘎拉徐爱菊内蒙古师范大学化学与环境科学学院内蒙古绿色催化重点实验室内蒙古呼和浩特010022

综述了BiVO4催化剂的结构和性质,以及提高其光催化降解有机污染物性能的方法。通过金属或非金属掺杂、结构和形貌改性、复合和负载等方法,可以调变BiVO4的结构和禁带宽度,增强电子的O2p→V3d(紫外光)或Bi6s(Bi6s/O2p)→V3d跃迁(可见光)... 详细信息

综述了BiVO4催化剂的结构和性质,以及提高其光催化降解有机污染物性能的方法。通过金属或非金属掺杂、结构和形貌改性、复合和负载等方法,可以调变BiVO4的结构和禁带宽度,增强电子的O2p→V3d(紫外光)或Bi6s(Bi6s/O2p)→V3d跃迁(可见光),并抑制e-/h+复合,以提高其光催化降解效率,并分析光催化降解的过程及机理。BiVO4催化剂稳定性好、无毒廉价、环境友好、制备方法简单,单斜白钨矿结构BiVO4具有较高的可见光活性,在光降解有机废水领域具有广泛的应用前景。

关键词：钒酸铋有机污染物光催化降解复合改性

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中国最老岩石和锆石

岩石学报 2009年第8期25卷 1793-1807页

作者：万渝生刘敦一董春艳 Nutman A Wilde sa 王伟颉颃强殷小艳周红英中国地质调查局天津地质矿产研究所澳大利亚科汀大学应用地质系北京离子探针中心中国地质科学院地质研究所

在中国大陆的许多地区都已发现大于3.4ga的锆石和岩石。鞍山是全球仅有几个存在≥3.8ga岩石的地区之一。它们以不大的规模存在于白家坟、东山、深沟寺杂岩中,由糜棱岩化奥长花岗岩、奈带状奥长花岗岩和变质石英闪长岩组成。近年来,在鞍... 详细信息

在中国大陆的许多地区都已发现大于3.4ga的锆石和岩石。鞍山是全球仅有几个存在≥3.8ga岩石的地区之一。它们以不大的规模存在于白家坟、东山、深沟寺杂岩中,由糜棱岩化奥长花岗岩、奈带状奥长花岗岩和变质石英闪长岩组成。近年来,在鞍山地区还发现了许多3.7～3.6ga岩石和锆石。锆石Hf同位素组成表明鞍山地区在3.8～3.6ga期间存在周期性的地幔添加和陆壳形成。除鞍山外,在中国许多地区的不同类型岩石中也获得了≥3.4ga锆石,虽然它们大多数都是碎屑和残余成因。(1)华北克拉通冀东铬云母石英岩中3.85～3.55ga碎屑锆石;(2)华北克拉通信阳中生代火山岩长英质麻粒岩中3.66ga岩浆锆石;(3)华南克拉通宜昌地区杨子地块新元古代砂岩中3.80ga碎屑锆石(一颗);(4)华南克拉通华夏地块新元古代-古生代变质沉积岩中3.76～3.6ga碎屑锆石;(5)西北地区塔里木地块阿克塔什塔格地区古元古代片麻状花岗岩中3.6ga残余锆石;(6)西秦岭奥陶纪变质火山岩中4.08ga捕掳锆石(一颗);(7)西藏普兰地区奥陶纪石英岩中4.1ga碎屑锆石(一颗,有3.61ga增生边)。一些古老锆石有高达4.1～4.0ga的Hf同位素模式年龄。在中国,>3.4ga地壳物质的比例以往被低估了,发现冥古宙和始太古代物质的可能性仍然存在,它们将对中国早期陆壳演化提供新的制约。

关键词：最古老岩石最古老锆石中国早期地壳演化锆石定年 Hf同位素

Lead-Time Reductions in SME's

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厦门大学学报(自然科学版) 2002年第S1期 245-246页

作者： d Ashall,B Parkinson design Technology.& Management University.of Hertfordshire design Technology.& Management University.of Hertfordshire Hatfield UK Hatfield UK

Background: Over recent y.ars many.manufacturing or ga nisations have focussed their attention on improving operational effectiveness. Whilst improvements made have increased the level of manufacturing efficiency. in many.cases these have not been reflected within SME's by.their response in me eting customer lead times. Aims: Whilst considerable efficiency.gains have been made in the manufacturing e nvironment the improvements achieved have not necessarily.been reflected in the attainment of customer delivery.times. The paper seeks to examine the reasons fo r this apparent anomaly.in as far as some SME's not meeting the lead times as qu oted to the customer. Using a case study.approach the authors will examine how a considerable number o f SME's are concentrating their efforts on reducing the lead-time of activities associated with the manufacturing process whilst pay.ng little attention to cos ts and activities indirect to the business. The paper will analy.e associated a spects involving the management of such organisations and assess if human resour ces are being used and deploy.d efficiently.and effectively. Using information obtained from recently.undertaken case studies the analy.is will encompass t he present-day.situation, economic climate, trends and fashion. Objectives: · Identify.some main reasons why.many.customer orders fail to be delivered on t ime. · Analy.e the link between customer and buy.r (Internally.and Externally. and the relevant theories of differing relationships from adversarial to partnership collaboration · Examine the trends in operational management to see how these impact upon the organisation · Confirm the ty.e of marketplace a responsive philosophy.is best suited · Examples will be supported by.case studies to highlight that SME's need to fo cus their attention outside the manufacturing process to gain a competitive advantage in reducing the lead-time. · Examine the effects and benefits on the organisation (b

关键词： Lead-Time Reductions in SME’s

有软弱通道土坝变形及溃决的离心模型试验研究

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长江科学院院报 2017年第8期34卷 101-105页

作者：闫冠臣张嘎清华大学水沙科学与水利水电工程国家重点实验室北京100084

土石坝稳定分析和溃坝机理研究具有重要的工程意义。离心模型试验通过离心力模拟重力,实现了模型试验应力与原型应力相等,是研究土石坝变形破坏过程的重要手段。围绕小型土坝在管涌工况下变形及溃决的特征和影响因素开展研究。在改进原... 详细信息

土石坝稳定分析和溃坝机理研究具有重要的工程意义。离心模型试验通过离心力模拟重力,实现了模型试验应力与原型应力相等,是研究土石坝变形破坏过程的重要手段。围绕小型土坝在管涌工况下变形及溃决的特征和影响因素开展研究。在改进原有的溃坝离心模型试验设备的基础上,进行了一系列有软弱通道土坝溃决的离心模型试验。试验结果表明有软弱通道坝体的溃决过程为:首先管涌通道形成并逐渐贯通,然后下部坝体逐渐冲蚀,同时上部坝体塌陷或塌落,最后整个坝体溃决。管涌通道贯通是坝体发生溃决的重要影响因素,甚至可能是其发生的先决条件。

关键词：软弱通道土坝离心模型试验溃坝变形

Major,trace element and Sr-Nd isotope evidence for a sublithospheric mantle source for the Umkondo large igneous province

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Geoscience Frontiers 2024年第1期15卷 263-285页

作者： Ben Hay.s Lewis d.Ashwal Khulekani B.Khumalo Linda M.Iaccheri School of Geosciences University of the WitwatersrandJohannesburg2050South Africa

The Mesoproterozoic(1.11 ga)Umkondo large igneous province(LIP)in southern Africa and Antarctica was emplaced in<5 My. and is dominated by.low-Ti tholeiitic doleritic-gabbroic *** is of particular interest because it ... 详细信息

The Mesoproterozoic(1.11 ga)Umkondo large igneous province(LIP)in southern Africa and Antarctica was emplaced iny. and is dominated by.low-Ti tholeiitic doleritic-gabbroic *** is of particular interest because it is the least studied LIP in southern Africa with both sublithospheric and lithospheric mantle sources proposed and it coincides with the early.assembly.of Rodinia,so it has importance in understanding the nature of magmatism and tectonics in and around the Kalahari craton during the *** this study.we compiled a large database of existing(~750)and new(~100)major and trace element data for the Umkondo province,as well as 42 new Sr-Nd isotopic measurements,to provide constraints on its magma sources and geochemical *** element compositional variations in the low-Ti tholeiites are explained by.low-pressure(1 kbar)three-phase fractional cry.tallisation(olivine,clinopy.oxene and plagioclase)of a parent magma with~10 wt.%MgO in oxidising conditions(QFM+1).Inverse models show that the low-Ti tholeiitic magmas were derived as residual melts after the cry.tallization of 12%-33%olivine from primary.komatiitic-basaltic magmas(up to~20 wt.%MgO)in equilibrium with mantle olivine(fo90).Low Sm/y. and TiO2/y.-Nb/y. indicate that the primary.magmas were derived by.2%-20%shallow(40-50 km)partial melting of spinel *** Sm/y. is restricted to dy.e swarms and may.imply.limited magma production from deeper(up to~70 km)garnet lherzolite-like *** low-Ti tholeiites of the Umkondo province are enriched in large ion lithophile elements(Rb-Sr-Cs-K)and depleted in high-field strength elements(Zr-Hf-Nb-Ta),indicating the involvement of crustal material and/or the subcontinental lithospheric *** is supported by.covariations in Th/Nb,Nb/y.,Nb/La and Ce/Sm with generally.negativeΔ***-Nd isotopes lend support to the notion that the Umkondo magmas were derived from depleted and/or enriched sublithospheric mantle sources and subs

关键词： Umkondo large igneous province Low-Ti magma Continental tholeiites Sublithospheric mantle sources Kalahari craton Rodinia

ALA对红掌叶片光合作用及叶绿素荧光参数的影响

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西北农林科技大学学报（自然科学版） 2009年第4期37卷 97-102页

作者：康博文李文华刘建军撒文清西北农林科技大学林学院陕西杨凌712100

【目的】探讨叶面喷施5-氨基乙酰丙酸（ALA）对红掌光合作用及叶绿素荧光参数的影响,为花卉植物上合理施用ALA奠定基础。【方法】选择3组红掌,每组60株,自2007-07-15-10-30,每15 d每组叶面分别喷施1次0（清水）,200和400 mg/L的ALA,利用... 详细信息

【目的】探讨叶面喷施5-氨基乙酰丙酸（ALA）对红掌光合作用及叶绿素荧光参数的影响,为花卉植物上合理施用ALA奠定基础。【方法】选择3组红掌,每组60株,自2007-07-15-10-30,每15 d每组叶面分别喷施1次0（清水）,200和400 mg/L的ALA,利用Li-6400光合测定系统和Li-6400-40荧光叶室分别测定不同质量浓度ALA处理对红掌叶片光合作用及叶绿素荧光参数指标的影响。【结果】与对照相比,200和400 mg/L ALA处理的红掌叶片叶绿素总量均极显著（P〈0.01）提高,提高幅度分别为6.7%和8.5%;1 d中（8：00-18：00）的光合速率显著提升,在较高光辐射强度下,光合速率的提高更为明显;初始荧光（fo）极显著（P〈0.01）地降低,降低幅度分别为7.5%和10.4%;最大荧光（Fm）、可变荧光（Fv）、最大光化学效率（Fv/Fm）、潜在光化学效率（Fv/fo）、光能获取能力（1/fo-1/Fm）依次提高0.3%和0.7%,2.5%和3.8%,2.2%和3.1%,10.7%和15.8%,10.4%和15.0%,差异达极显著（P〈0.01）或显著（P〈0.05）水平;200和400 mg/L ALA处理对有效光化学速率（Fv′/Fm′）的影响不显著（P〉0.05）,但可使ФPSⅡ分别提高42.4%和66.7%,NPQ分别提高2.1%和3.3%,qP分别提高43.0%和67.7%,差异均达显著水平（P〈0.05）;可使PCR分别降低13.9%和40.0%,ETR分别提高37.1%和61.9%,差异均达极显著水平（P〈0.01）。【结论】喷施ALA可以提高红掌叶片的光化学效率,对降低不良环境的胁迫有积极作用,因而其可以在红掌上施用。

关键词：红掌 5-氨基乙酰丙酸(ALA) 光合速率叶绿素荧光

基于mtdNA d-loop序列分析青海省果洛州牦牛遗传资源的母系遗传多样性及群体遗传结构

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中国农业大学学报 2024年第8期29卷 134-146页

作者：曹萍梅萨陈生梅李鸿康郭卫兴李瑞哲达桑才加莫延新官却扎西忠尕李文浩刘书杰崔宏伟马志杰青海大学畜牧兽医科学院/青海省高原家畜遗传资源保护与创新利用重点实验室/农业农村部青藏高原畜禽遗传育种重点实验室青海省果洛州班玛县畜牧兽医站青海省牦牛繁育推广服务中心青海省果洛州久治县索乎日麻乡畜牧兽医站青海省果洛州玛多县花石峡镇措柔村拉泽生态畜牧业专业合作社青海省畜禽遗传资源保护利用中心青海省果洛州农牧和科技局

为从分子水平上对青海省果洛藏族自治州牦牛遗传资源进行系统评估，分析其母系遗传多样性、群体遗传结构和群体遗传分化，本研究对甘德、班玛、久治和玛多牦牛群体共152头个体进行线粒体dNA(mtdNA)dloop区测序，并从GenBank下载已公布... 详细信息

为从分子水平上对青海省果洛藏族自治州牦牛遗传资源进行系统评估，分析其母系遗传多样性、群体遗传结构和群体遗传分化，本研究对甘德、班玛、久治和玛多牦牛群体共152头个体进行线粒体dNA(mtdNA)dloop区测序，并从GenBank下载已公布的37条达日牦牛和32条玛沁牦牛的相应序列，对这6个牦牛群体mtdNA d-loop序列进行综合分析。结果表明：1)221条牦牛mtdNA d-loop序列（636～638 bp）比对分析共检测出57个变异位点，包括8个单一多态位点和49个简约信息位点。根据d-loop序列间核苷酸变异共确定了45种单倍型，其中班玛、达日、甘德、久治、玛多、玛沁牦牛群体分别拥有1、6、5、4、7、6种特有单倍型。2)6个牦牛群体总的单倍型多样度和核苷酸多样度为0.901和0.014，表明其母系遗传多样性丰富。其中，甘德牦牛的单倍型多样度最高（Hd=0.951），久治牦牛的单倍型多样度最低（Hd=0.818）。3）遗传分化和基因流分析表明，除久治牦牛与班玛、甘德、玛沁牦牛群体间分化程度均呈中等遗传分化水平（0.05≤FSTdivSummary., 'ChdivSummary.ore', 'ChdivSummary.eset');

关键词：牦牛 mtdNA d-loop区遗传多样性遗传分化群体结构系统发育