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release rate kinetics of corrosion inhibitor loaded halloysite nanotube-based anticorrosion coatings on magnesium alloy AZ91D

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Journal of Magnesium and Alloys 2021年第1期9卷 202-215页

作者： Swapnil H.Adsul Uday D.Bagale Shirish H.Sonawane R.Subasri Centre for Sol-Gel Coatings International Advanced Research Centre for Powder Metallurgy and New Materials(ARCI)BalapurHyderabad 500005Telangana StateIndia Department of Food and Biotechnology South Ural State UniversityChelyabinsk 454080Russia Department of Chemical Engineering National Institute of TechnologyWarangal 506004Telangana StateIndia

Halloysite nanotubes were used as nanocontainers to hold corrosion inhibitors such as Ce^(3+)-Zr^(4+),2-mercaptobenzothiazole and 8-hydroxyquinoline in their *** acid assisted etching of the nanotubes was carried out with a view to increase the lumen diameter and thereby,increase the amount of loading of the corrosion *** morphology of as-received and etched halloysite nanotubes was ob-served using TEM *** loading of corrosion inhibitors was confirmed using SEM-EDS and BET *** microcapsules were used as capping agents for the ends of the loaded HNTs following which,they were dispersed into a hybrid sol-gel silica *** coating method was used to generate coatings on AZ91D substrates followed by heat treatment at 130℃ for 1 *** release rate kinetics of corrosion inhibitors from as-received and etched nanotubes was investigated in buffer solutions of 3.5 wt%NaCl at different *** release mechanism of corrosion inhibitors from the HNT lumen was validated using various semi-empirical *** were also evaluated for their corrosion protection ability using electrochemical techniques after exposure to 3.5 wt%NaCl solution for 120 *** generated using Ce^(3+)-Zr^(4+)loaded into as-received halloysite nanotubes have shown more effective corrosion protection when compared to other corrosion inhibitors after 120 h exposure to the corrosive medium.

关键词： Sol-gel coating Halloysite nanotubes Corrosion inhibitors release rate Magnesium alloy AZ91D

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release kinetics of vanadium from vanadium titano-magnetite：The effects of pH, dissolved oxygen, temperature and foreign ions

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Journal of Environmental Sciences 2018年第2期30卷 298-305页

作者： Xingyun Hu Yuyan Yue Xianjia Peng National Engineering Laboratory for Industrial Wastewater Treatment Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Beijing Key Laboratory of Industrial Wastewater Treatment and Resource Recovery Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China University of Chinese Academy of Sciences Beijing 100190 China School of Environment Henan Normal University Xinxiang 453007 China

As part of a broader study of the environmental geochemistry behavior of vanadium（V）, the release kinetics of V from the dissolution of natural vanadium titano-magnetite under environmentally relevant conditions was investigated. In both the acidic and basic domains, the V release rate was found to be proportional to fractional powers of hydrogen ion and dissolved oxygen activities. The dependence of the rate on dissolved oxygen can also be described in terms of the Langmuir adsorption model. The empirical rate equation is given by： r= k′α（H＋）α（Kα（O2））/（1＋Kα（O2）） where, α = 0.099–0.265, k′ = 3.2 × 10-6–1.7 × 10-5, K =2.7 × 104–3.9 × 104 mol/L in acid solution（pH 4.1）, and α =-0.494-（-0.527）, k′ = 2.0 × 104–2.5 × 10-11, and K = 4.1 × 103–6.5 × 103 mol/L in basic solution（pH 8.8） at 20°C. Based on the effect of temperature on the release rate of V, the activation energies of minerals at p H 8.8 were determined to be 148–235 k J/mol, suggesting that the dissolution of vanadium titano-magnetite is a surface-controlled process. The presence of Na＋, Ca2＋, Mg2＋, K＋, NO3-, Cl-, SO42-and CO32-was found to accelerate the V release rates. This study improves the understanding of both the V pollution risk in some mine areas and the fate of V in the environment.

关键词： Vanadium release rate Hydrogen ion Dissolved oxygen

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Fabrication and Properties of Multilayer Chitosan Membrane Loaded with Tinidazole

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Journal of Wuhan University of Technology(Materials Science) 2007年第1期22卷 102-107页

作者：洪华刘昌胜 Engineering Research Center of Biomedical Materials under Ministry of Education East China University of Science and Technology

With the aim of providing effective periodontal disease therapeutic method, multilayer membranes which were loaded with drug for guided tissue regeneration were prepared using an immerseprecipitation phase inversion technique. Single layer, bi-layer and tri-layer membranes were fabricated with chitosan used as cartier and tinidazole as medicine model which was loaded on the membrane. The influence of layer on structure and properties of membrane were studied by SEM, UV spectrophotometer and mechanical test. Drug release properties of three types of layer membranes were also investigated. The results showed that release rate could be slown down in both bi-layer and tri-layer membranes （to 11 days and 14 days respectively） and tri-layer membrane lasted the longest. After a process of rapid release, the concentration of tinidazole which was released by the membrane was maintained at an efficient dosage level. Compared with single layer and bi- layer membranes, we found tri-layer membrane could play a role in controlling low-rate drug release especially at the early stage of release, and keep an efficient dosage at affected part for a long period of time. The loss of drug which loaded on membrane decreased from 84.6% for single layer to 13.04% for tri-layer. The mechanical strength of three types of membrane were detected and showed that it could meet the requiremens of clinical practice. The membranes especially with tri-layer could be more valuable in application.

关键词： chitosan membrane multilayer drug loss release rate

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Factors influencing the drug release from calcium phosphate cements

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Bioactive Materials 2022年第1期7卷 341-363页

作者： Marco Fosca Julietta V.Rau Vuk Uskokovi Istituto di Struttura della Materia Consiglio Nazionale delle Ricerche(ISM-CNR)Via del Fosso del Cavaliere 10000133RomeItaly I.M.Sechenov First Moscow State Medical University Institute of PharmacyDepartment of AnalyticalPhysical and Colloid ChemistryTrubetskaya 8build.2119991MoscowRussia Advanced Materials and Nanobiotechnology Laboratory TardigradeNano LLCIrvineCA 92604United States

Thanks to their biocompatibility,biodegradability,injectability and self-setting properties,calcium phosphate cements(CPCs)have been the most economical and effective biomaterials of choice for use as bone void *** have also been extensively used as drug delivery carriers owing to their ability to provide for a steady release of various organic molecules aiding the regeneration of defective bone,including primarily antibiotics and growth *** review provides a systematic compilation of studies that reported on the controlled release of drugs from CPCs in the last 25 *** chemical,compositional and microstructural characteristics of these systems through which the control of the release rates and mechanisms could be achieved have been *** doing so,the effects of(i)the chemistry of the matrix,(ii)porosity,(iii)additives,(iv)drug types,(v)drug concentrations,(vi)drug loading methods and(vii)release media have been distinguished and discussed *** specificities of in vivo release of drugs from CPCs have been reviewed,*** the kinetic and mechanistic correlations between the CPC properties and the drug release is a prerequisite for the design of bone void fillers with drug release profiles precisely tailored to the application area and the clinical *** goal of this review has been to shed light on these fundamental correlations.

关键词： Calcium phosphate cements Drug release release rate Antibiotics release Bone fillers

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An Experimental Study on Major Element release from the Sediments in the Changjiang(Yangtze River) Estuary

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Journal of Ocean University of China 2015年第3期14卷 417-424页

作者： GUO Yanwei YANG Shouye State Key Laboratory of Marine Geology Tongji University

With the enhanced warming and acidification of global ocean, whether and to what extent the naturally-weathered flu- vial sediment into the sea can release elements and thus influence the geochemical process and ecosystem of global ocean remain to be resolved. In this contribution, an experimental study was carried out to examine the release rates of major elements （Ca, K, Mg and AI） from the surface sediments in the Changjiang （Yangtze River） Estuary under the pH values of 4.0, 6.0 and 7.0. The two stud- ied sediments consist primarily of quartz, plagioclase, calcite and clay minerals, with the BET （Brunauer, Emmett and Teller） surface areas of 61.7m2g-1 and 23.1 m2g-1. Major elements of Ca, K, Mg and A1 show different release rates under different solution pH values. With the decreasing solution pH, the release rates of Ca and K increase obviously, while the release rates of Mg and A1 in- crease with the initial solution pH varying from 6.0 to 7.0. The different release rates of these elements are closely related to the original mineral composition of the sediments and the reaction kinetics. Based on the experimental observation, quartz and clay min- erals that have low dissolution rates may dominate the major element release to the aqueous phase. This study reveals that the en- hancing ocean acidification could cause considerable release of major elements from natural terrigenous sediments into the ambient marine environment, which has to be considered carefully in the future study on global change.

关键词： Changiiang Estuary major elements release rate pH value sediment

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Improved method for nondestructive measurement of dynamic pollen source strength from transgenic crops using sonic anemometer

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International Journal of Agricultural and Biological Engineering 2009年第1期2卷 33-39页

作者： Junming Wang Xiusheng Yang Department of Plant and Environmental Sciences New Mexico State UniversityLas CrucesNM 88003-8003USA Department of Natural Resources and the Environment University of ConnecticutStorrsCT 06268-4087USA

Pollen-mediated gene flow from transgenic crops is a concern of the scientific community as well as the general *** lack is a nondestructive method to measure dynamic(hourly or shorter time period)source pollen release rate(source strength)from these *** paper reports an improved method using Rotorod concentration samplers and sticky slides,together with a fast response sonic anemometer,for measuring source strength from transgenic corn *** measurements were made during the pollination season of 2001 at the Agronomy Research Farm,University of Connecticut,Storrs,*** were analyzed and used to estimate the pollen source strength of the corn crops at hourly time steps by considering both atmospheric transport and gravitational deposition *** of the calculation and assumptions of the method are *** from this study demonstrate that this method is sufficiently robust for use in estimating pollen source strength of transgenic crops with heavy pollen grains in assessing gene flow risks associated with field production of transgenic crops.

关键词： corn pollen gene flow release rate source strength transgenic crops

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缓慢释放孕酮宫内节育器的体内释药研究及对垂体—卵巢轴影响的探讨

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中华生殖与避孕杂志 1986年第3期 14-19页

作者：张美云郭泉清潘家骧严隽鸿上海第二医学院附属第三人民医院

本文依据雌性家兔及人体内使用9%乙烯醋酸乙烯(9%Ethylene Vinyl Acetate,简称EVA)共聚物作为释药系统,含一定量孕酮的宫内节育器,经过使用不同时间后分别取出测定剩余的孕酮量,观察本释药系统在体内的药物释放情况。测定结果证明家兔... 详细信息

本文依据雌性家兔及人体内使用9%乙烯醋酸乙烯(9%Ethylene Vinyl Acetate,简称EVA)共聚物作为释药系统,含一定量孕酮的宫内节育器,经过使用不同时间后分别取出测定剩余的孕酮量,观察本释药系统在体内的药物释放情况。测定结果证明家兔体内释放符合零级动力学,即恒速释放,释放速度为46.6μg/cm~2/天。在人体内也达到恒速释放,释药速度为29μg/cm~2/天。此外对四名育龄妇女进行上环前一个周期及上环后九个月至一年的基础体温、宫颈粘液、阴道脱落细胞成熟指数及血清促黄体生成激素、促卵泡激素、雌二醇和孕酮的放射免疫测定的系统纵向观察,结果证明受试者上环后每个周期均有排卵,释放孕酮量为29μg/cm~2/天的宫内节育器对机体垂体-卵巢轴无显著影响。

关键词： Progesterone Intrauterine delivery system release rate Pituitary-ovarian axis

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Research on Fluorine release of coal and clay used by residents in Zhaotong Fluorosis areas,Yunnan Province

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Journal of Coal Science & Engineering(China) 2010年第1期16卷 78-81页

作者： LI Hui-jie Research Center for Environmental Remediations and Resources Engineering Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The Fluorine release rate of coal, clay of different Fluorine content, and coal mixed with clay used by resident households were studied by using the ion selective electrode （ISE） and solidoid balance methods, and the degree of influence on Fluorine pollu- tion generated by coal and clay was analyzed according to the proportion characteristics of coal used by resident households. The results show that the Fluorine release rate of coal is more than 95% during combustion; The Fluorine release rate of clay is more than 99%; The Fluorine release rate of coal mixed with clay is between 56.44% and 96.64%, and the average value is 76.68%. The clay as a binder for fine coal is one important source of Fluorine pollution caused by coal-combustion in Zhaotong, Yunnan Province. When the Fluorine content of coal is less than 80 mg/kg, the F[uodne amount released from clay （in which Fluorine content is more than 530 mg/kg） is more than 50% of the total Fluorine amount released from coal and clay during coal-combustion. The Fluorine amount released from clay （in which Fluorine content is more than 1 000 mg/kg） is more than 70% of total Fluorine amount released from coal and clay during coal-combustion.

关键词： Zhaotong source of Fluorine pollution release rate clay of different content

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Influence of Preparation Factors on the Sustained release of Nifedipine from Eudragit RL/RS Microspheres

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Journal of Chinese Pharmaceutical Sciences 1997年第4期6卷 31-38页

作者：傅崇东蒋雪涛胡晋红张万国第二军医大学药学院药剂教研室第二军医大学长海医院药剂科

Sustained release Eudragit RL/RS microspheres encapsulating nifedipine were prepared using the acetone/liquid paraffin emulsion solvent evaporation method. The influence of different preparation factors on release of the drug in vitro was investigated. The release rate of nifedipine from the microspheres increased with increasing Eudragit RL/RS ratio and stirring rate during the preparation, and with decreasing the polymer concentration of internal phase and microsphere size. It was found that a linear relationship existed between the microsphere size and the time of 50% drug release. The drug release rate increased with increasing nifedipine content from 4.2 to 16.7% and was more rapid than the dissolution rate of pure nifedipine particles. However, the release rate of the microspheres with 26.6% drug content decreased significantly and was slower than the dissolution rate of pure drug particles. This was attributed mainly to the nifedipine dispersion state in the microspheres as confirmed by the differential thermal analysis and X ray diffraction study, which showed that nifedipine was present in an amorphous or molecular state in the microspheres with 4.2, 9.4 and 16.7% drug, whereas partly in the crystalline state in the microspheres with 26.6% drug. The amounts released for less than 70% nifedipine can be fitted to Higuchi square root of time model, independent of polymer ratio, drug content and microsphere size.

关键词： Sustained release microspheres Nifedipine Eudragit RL/RS release rate

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Protective Effects of Rumen Protected Choline in Dairy Cows

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Animal Husbandry and Feed Science 2010年第4期2卷 26-28,31页

作者： XIAO Jin GAO Yan-xia CAO Yu-feng LI Qiu-feng LI Jian-guo College of Animal Science and Technology Agricultural University of Hebei Baoding 071000 China

Choline is a necessary nutrient for dairy cows and contributes to milk yield, but most of dietary choline can be degraded by the microorganisms in rumen. Rumen protected choline （RPC） has been developed to protect choline from degradation. To screen stable RPC, choline chloride was coated with acrylic resin no. IV, chitosan and the mixture containing the two lagging covers by fluidized bed coating technology, respectively. Their stability was evaluated in vitro and in situ. The results showed that release rate of RPC coated with acrylic resin no. IV and chitosan was the lowest in rumen and pH 6.6 buffer. And its effective protection rate reached 62.04% in rumen. Therefore, RPC coated with acrylic resin no. IV and chitosan has good stability and protection efficacy in rumen, and it can be used in practice to supply effective choline for the ruminant.

关键词： Rumen protected choline Holstein cows release rate

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