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Thermodynamic and experimental studies on removal of calcium and sulfate ions from recycling water of complex sulfide flotation operations

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Transactions of Nonferrous Metals Society of China 2021年第10期31卷 3116-3127页

作者： elvis BUSTOS-FLORES Martha Araceli ELIZONDO-ÁLVAREZ Alejandro URIBE-SALAS Department of Metallurgical Engineering CINVESTAV-IPNUnidad Saltillo25900Ramos ArizpeCoahuilaMexico

A chemical method for removing calcium sulfate saturated solutions(0.016 mol/L CaSO_(4))using barium chloride(BaCl_(2)∙2h_(2)O)and sodium phosphate(Na_(3)PO_(4))was experimentally *** main interest is to remove these ions from the solution through the precipitation of two solid species:sulfate(SO_(4)^(2−))as barite(BaSO4),and calcium(Ca^(2+))as hydroxyapatite(Ca_(5)(PO_(4))_(3)Oh).Additionally,a solid/liquid separation method(i.e.,flotation)was explored,using oleic acid and dodecylamine as *** results show that,the chemical treatment of saturated solutions at 60℃,ph 11.5 and using 3.9 g/L BaCl_(2)·2h_(2)O and 1.6 g/L Na_(3)PO_(4),promotes the precipitation of barium sulfate and calcium-deficient hydroxyapatite(Ca_(10−x)(hPO_(4))_(x)(PO_(4))_(6−x)(Oh)_(2−x)),with residual concentrations of calcium and sulfate below 0.10 and 5 mg/L,*** residual calcium concentration increases to 28 mg/L when using the same amount of reactants,at temperature and ph values below those *** highest flotation recovery of hydroxyapatite with oleic acid at ph 9.5 was about 80%,while that of barite floated with dodecylamine at ph 6.5 was about 90%.

关键词： calcium sulfate dodecylamine oleic acid barite hydroxyapatite flotation separation

ph-dependent leaching mechanism of carbonatitic chalcopyrite in ferric sulfate solution

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Transactions of Nonferrous Metals Society of China 2021年第7期31卷 2139-2152页

作者： kolela J NYEMBWE elvis FOSSO-kANkEU Frans WAANDERS Martin MkANDAWIRE Water Pollution Monitoring and Remediation Initiatives Research Group School of Chemical and Minerals EngineeringFaculty of EngineeringNorth-West UniversitySouth Africa Department of Chemistry School of Science and TechnologyCape Breton UniversityCanada

The dissolution of a carbonatitic chalcopyrite(CuFeS2)was studied in h_(2)SO_(4)−Fe_(2)(SO_(4))_(3)−FeSO_(4)−h_(2)O at varying ph values(0.5−2.5)and 25℃ for 12 *** were conducted with a size fraction of 53−75μ*** Cu recoveries,below 15%,were observed in all ph *** results from the XRD,SEM−EDS,and optical microscopic(OM)analyses of the residues indicated that the dissolution proceeded through the formation of transient ***_(3.39)Fe_(0.61)S_(4) and Cu_(2)S were the intermediate phases at ph 0.5 and 1.0,respectively,whereas Cu_(5)FeS_(4) was the major mineral at ph 1.5 and *** thermodynamic modelling predicted the sequential formation of CuFeS_(2)→Cu_(5)FeS_(4)→Cu_(2)S→*** soluble intermediates were Cu_(5)FeS_(4) and Cu2S,whilst,CuS and Cu_(3.39)Fe_(0.61)S_(4) were the refractory phases,supporting their cumulating behaviour throughout the *** obtained results suggest that the formation of CuS and Cu_(3.39)Fe_(0.61)S_(4) could contribute to the passive film formed during CuFeS_(2) leaching.

关键词： chalcopyrite carbonatite chemical leaching leaching mechanism intermediate phase thermodynamic behavior

In vivo antiplasmodial and in vitro antioxidant property of stem bark extracts of haematostaphis barteri

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Asian Pacific Journal of Tropical Biomedicine 2015年第6期5卷 444-448页

作者： Johnson Nyarko Boampong Akua Afryie karikari elvis Ofori Ameyaw Department of Biomedical and Forensic Sciences University of Cape Coast

Objective: To evaluate the antimalarial and antioxidant properties of stem bark extracts of haematostaphis barteri(h. barteri).Methods: The prophylactic activity of the plant was performed by dosing mice with sulfadoxine-pyrimethamine(1.2 mg/kg), aqueous extract(30, 100, 300 mg/kg) and dichloromethane/methanol(D/M)(30, 100, 300 mg/kg) extracts of h. barteri for 3 days. On the 4th day, the mice were inoculated with Plasmodium berghei. The parasite density was estimated for each mouse 72 h post-parasite inoculation. The curative activity of the plant was also performed by inoculating mice with Plasmodium berghei. Three days later, they were treated with artemether-lumefantrine(4 mg/kg), aqueous and D/M extracts of h. barteri stem bark for 5 days. The in vitro antioxidant property of the aqueous extract was determined by using the reducing power, nitric oxide and total antioxidant capacity assays. Results: The aqueous extract exerted significant(P hylactic antimalarial activities. The D/M extract exhibited significant curative(P hylactic antiplasmodial ef ect. The aqueous extract exhibited in vitro antioxidant property with IC50’s of(0.930 ± 0.021) mg/mL,(0.800 ± 0.001) mg/mL and(0.22 ± 0.05) mg/mL in the total antioxidant capacity, reducing power and nitric oxide assays. histological assessment of the liver of aqueous and D/M treated animals did not reveal any sign of ***: h. barteri is not toxic which exerted significant curative antiplasmodial ef ects but the prophylactic property was however fraction dependent. The mechanism of the antiplasmodial activity of h. barteri may partly be mediated by its antioxidant property.

关键词： Malaria Parasitemia haematostaphis barteri Antioxidants Phytochemicals

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全球疫情大流行:如何更好应对?

英国医学杂志中文版 2019年第1期22卷 9-13页

作者： Jennifer Leigh Gabrielle Fitzgerald elvis Garcia Suerie Moon 唐咸艳(译) 周红霞(校) hazard T h Chan School of Public health BostonMA USA Panorama Global SeattleWashington USA Global health Centre Graduate Institute of Geneva Switzerland 广西医科大学公共卫生学院广西医科大学外国语学院

Jennifer Leigh及同行们报告说,尽管已经发起了多项倡议以提高全球应对重大疫情暴发的能力,但现实存在的差距仍令人担忧。

关键词：疫情暴发大流行

Synthesis, Molecular Structure and Antibacterial Activity of Benzylmethyl-4-Methyl-3-Thiosemicarbazone

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International Journal of Organic Chemistry 2017年第2期7卷 83-90页

作者： James A. Mbah Godfred A. Ayimele elvis N. Eyonganyoh Emmanuel N. Nfor Department of Chemistry University of Buea Buea Cameroon

A novel Schiff base, benzylmethyl-4-methyl-3-thiosemicarbazone (BMM) de-rived from benzylmethylketone and 4-methylthiosemicarbazide was synthe-sized and characterized by elemental analysis, spectroscopic methods (IR, 1h NMR, 13C NMR) and physical means. The single crystal structure analysis of the Schiff base reveals that it crystallizes in a monoclinic system in the P21/c space group. BMM revealed moderate antibacterial activity on three bacterial strains with diameter zone of inhibition of 16 mm (E. coli), 14 mm (k. pneumonia) and 13 mm (S. epider-midis) compared with the standard drug, ciprofloxacin.

关键词： Benzylmethyl-4-Methyl-3-Thiosemicarbazone Antibacterial Activity Crystal Structure

Time to integrate“One health Approach”into nanoplastic research

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Eco-Environment & health 2023年第1期2卷 18-20页

作者： Mohamed helal Nanna B.hartmann Farhan R.khan elvis Genbo Xu Department of Biology University of Southern DenmarkOdense5230Denmark Department of Environmental and Resource Engineering Technical University of Denmark2800 Kgs.LyngbyDenmark Norwegian Research Centre(NORCE) Nygårdsporten 112NO-5008BergenNorway

Large-scale production of plastics began in the 1950s followed by an onset of exponential growth,leading to its current widespread and dominant *** this,no holistic risk assessment has yet been made on the health and environmental impacts of plastics,their degradation products,or their constituent *** entering the environment,plastics undergo structural,chemical,and functional transformations,leading to the creation of microplastics and nanoplastics[1,2,3].Environmental exposure to microplastics and nanoplastics becomes inevitable,causing direct human dietary exposure.

关键词： plastics integrate spite

Effect of crude methanol leaf extract ofCombretum racemosum on histamine-stimulated gastric secretion in rats

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Journal of Coastal Life Medicine 2017年第2期5卷 77-81页

作者： Chukwugozie Nwachukwu Okwuosa Nkiruka Chinonyelum Azubike Daniel Chukwu Nwachukwu Augustine Chukwudum Onuba elvis Neba Shu Department of Medical Laboratory Sciences Faculty of Health Sciences and TechnologyCollege of MedicineUniversity of NigeriaEnuguNigeria Department of Physiology Faculty of Basic Medical SciencesUniversity of NigeriaEnuguNigeria Department of Veterinary Surgery Faculty of Veterinary MedicineUniversity of NigeriaEnuguNigeria Department of Pharmacology and Therapeutics Faculty of Medical SciencesCollege of MedicineUniversity of NigeriaEnuguNigeria

Objective:To investigate the effect of crude methanolic extract of Combretum racemosum (C. racemosum) leaves on histamine-stimulated gastric secretion in rats. Methods: Phytochemical and acute toxicity tests were performed. Anti-secretory activity of C. racemosum extract was investigated in pyloric ligated rats administered histamine. Gastric juice was collected from all the animals and the volume, titratable acidity, ph and mucus content were measured. The effect of C. racemosum extract on calcium chloride induced contractions of the guinea-pig ileum suspended in high potassium, calcium-deficient depolarizing solution was investigated. The h2 receptor antagonistic potency was also evaluated using the isolated non-gravid rat uterus. Results:Phytochemistry revealed the presence of abundant amounts of saponins and moderate amounts of glycosides, terpenoids, proteins, reducing sugar, resins, alkaloids, flavonoids and carbohydrates. The oral LD50 of the extract was greater than 8000 mg/kg body weight in mice. Pretreatment of pyloric ligated rats with C. racemosum prior to histamine administration significantly reduced (P he volume of gastric juice and titratable acidity, and significantly increased (P h and gastric mucus when compared to the negative control. Both doses ofC. racemosum protected rats significantly (P histamine-induced ulceration.C. racemosum potently inhibited contractions evoked by calcium chloride in a dose-dependent and reversible manner with an IC50 of 1132μg/*** also antagonized the relaxant effect of histamine on the isolated rat uterus in a manner comparable to cimetidine. Conclusions: The leaves of C. racemosum possess gastric anti-secretory and anti-ulcer effects and justify its use in traditional medicine in South-East Nigeria for the treatment of peptic ulcer disease.

关键词： Combretum racemosum Anti-secretory activity h2 receptor Titratable acidity CaCl2 ph

某矿低成本细粒级尾砂捕收用新型胶束剂材料工业应用可行性研究

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某矿低成本细粒级尾砂捕收用新型胶束剂材料工业应用可行性研究

作者：梁浩坚（elvis Leung）广州大学

学位级别：硕士

尾矿库无法退库一直是制约国内外矿山扩大生产规模,实现可持续性开采过程中的首要问题。目前国内外应用于实际工业生产的尾矿处理方法主要是絮凝剂结合浓密机,圆盘过滤机等机械,实现尾矿中的水砂分离,从而达到水资源回用、尾矿颗粒充填... 详细信息

尾矿库无法退库一直是制约国内外矿山扩大生产规模,实现可持续性开采过程中的首要问题。目前国内外应用于实际工业生产的尾矿处理方法主要是絮凝剂结合浓密机,圆盘过滤机等机械,实现尾矿中的水砂分离,从而达到水资源回用、尾矿颗粒充填再利用。而水砂分离程度低、资源回收效率低是当下国内外矿山所面临的主要技术难题。以我国南方某铅锌矿为例,近3年(2017年～2019年)该矿山选矿厂尾矿产量平均为原矿石的40%,尾矿中粗粒级尾砂(即分级尾砂)回收率平均为45%,而尾矿中约有55%的细粒级尾砂(19μm以下尾矿颗粒)排往尾矿库,一年约产生200万吨无法利用的尾矿。面临全国尾矿库退库的环保任务,当前的尾砂回收率远远无法达到要求。因此从提高水砂分离效率角度出发,结合课题组前期研发胶束剂材料及矿山现有生产条件,开展关于新型低成本细粒级尾砂捕收用新型胶束剂材料工业应用可行性研究具有重要的战略意义。本文以我国南方某铅锌矿细粒级尾砂捕收用新型胶束剂材料工业应用研究的重点科研项目为依托,以课题组前期研发的新型胶束剂(成分主要为混凝剂羟基铝与助凝剂聚丙烯酰胺、聚合氯化铝铁)为基础,通过分析尾矿的物理化学特性及室内可行性实验,从理论上验证其替代某矿山现用絮凝剂的可能性及可行性。随后通过室内实验结合工业现场实验的方式探索出胶束剂工业生产最优可调使用浓度为0.1g/L(0.1%)、最优可调使用用量为15ml/L、最优给料浓度为12%。并从沉淀效果(沉淀速度,沉淀干重)及上清液水质(COD、p h、ORP)两个维度研究胶束剂在工业生产环境中的实际应用效果,研究证明课题组胶束剂在实际生产中能有效提高细粒级尾矿的回收率,同时能为矿山提供大量可用清水,适用于矿山日常生产。最后通过分析材料成本、清水回用节省成本、尾矿库运营成本三个方面研究胶束剂应用所能带来的经济红利。本文主要研究内容及结论如下:(1)实验前期通过引入X射线衍射仪(XRD)、X射线荧光光谱分析仪(XRF)、分析30m浓密机尾砂浆料的化学性质,引入激光粒度分析仪对30m浓密机尾砂浆料的物理性质进行微观分析。确定三种尾砂浆料主要含有硝酸离子NO2-,NO3-及硫酸离子SO2-矿浆整体呈弱碱性且铅锌含量均低于1%。通过水分析(水筛)实验进一步确定30m浓密机给料浆料,03尾砂及全尾砂的19μm以下粒径分布情况。明确了30m浓密机矿浆中19μm以下微粒占比大于90%。提出一种矿山尾砂沉淀专用胶束剂,其配方组合为:混凝剂(羟基铝)53%、助凝剂1(聚丙烯酰胺)27%、助凝剂2(聚合氯化铝铁)15%、复合添加剂5%。结合其物化性能分析结果,得出结论,三类尾砂物理化学性质均有利于胶束剂(絮凝剂)发挥作用。胶束剂具备应用于尾砂捕获的可能性。(2)开展课题组胶束剂处理30m浓密机尾砂给料料浆的可行性实验。确认室内试验环境中胶束剂最优使用浓度为0.1g/L(0.1%)。同时证实了胶束剂在沉淀速度,沉淀效果(沉淀干重,沉淀污泥体积)及上清液p h值、COD及ORP指标方面均较某矿现用絮凝剂尾砂有明显优势,具备替代絮凝剂的可行性。(3)于现场开展胶束剂现场确认实验,为工业实验做准备。确认实验旨在排除30m浓密机矿浆水浓度变化及样品新鲜程度两大变量对胶束剂应用效果产生的影响,并进一步验证胶束剂相较于现用絮凝剂应用于工业生产时具备优势。结合室内可行性实验结果于矿山实验室现场进一步确认胶束剂浓度0.1g/L(0.1%)为工业试验可调最优浓度,15ml/L为工业试验可调最优用量,给料浓度12%为胶束剂工业应用最优给料浓度。(4)开展胶束剂工业应用实验。通过工业实验对比胶束剂与絮凝剂应用于实际工业生产的效果。得出结论为:胶束剂在使用浓度为0.1g/L(0.1%)、药剂用量为15ml/1000ml(15ml/L)、给料平均浓度12%时能有效提高尾砂总产量10%,提高细粒级尾砂产量33%;上清液水质方面,在同样药剂浓度及用量下,使用胶束剂后获得的上清液在感官,微观悬浮物检测数据及COD数据三方面优于该铅锌矿现用絮凝剂,证明了胶束剂工业应用适用性。(5)进一步开展胶束剂沉淀回收利用于井下充填的效果研究。结合当地水泥厂生产的42.5R水泥及03尾砂,于工业生产系统进行现场充填实验并在-750m矿井下取样制作试块,测试多组试块的3天,7天及28天立方体抗压强度数据。得出结论:在水泥变频55hz,灰砂比1:4情况下,混合胶束剂沉淀所得细粒级尾砂后的03尾砂作为骨料的充填体较03尾砂混合絮凝剂沉淀作为骨料的充填体在强度上具有明显优势。虽依然无法达到3天3Mpa的要求,但从3天强度来看相较03尾砂混合絮凝剂沉淀骨料对照组拥有78%的提升。可见胶束剂沉淀的细粒级尾砂和03尾砂混合作为充填骨料进行充填的工业应用具有一定意义,可进行推广应用。(6)结合某铅锌矿现用絮凝剂

关键词：某铅锌矿新型矿山胶束剂尾砂处理低成本尾矿库工业应用

Intestinal epithelial cell turnover is an adaptive response to diet-induced enteritis in Atlantic salmon(Salmo salar L)

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Intestinal epithelial cell turnover is an adaptive response ...