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Structural, compositional and mineralogical characterization of carbonatitic copper sulfide: Run of mine, concentrate and tailings

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International Journal of Minerals,Metallurgy and Materials 2019年第2期26卷 143-151页

作者： Kolela J Nyembwe elvis Fosso-Kankeu Frans Waanders Kasongo d Nyembwe Water Pollution Monitoring and Remediation Initiatives Research Group School of Chemical and Minerals Engineering Faculty of Engineering North-West University School of Mining Metallurgy and Chemical Engineering Faculty of Engineering and the Built Environment University of Johannesburg

The aim of this study was to determine the structural, compositional, and mineralogical composition of carbonatitic copper sulfide concentrator plant streams. Three samples, each from a different stream(run of mine(ROM), concentrate, and tailings) of a copper concentrator were characterized using various techniques, including stereomicroscopy, X-ray fluorescence, X-ray diffraction, Fourier transform infrared(FTIR) spectroscopy, scanning electron microscopy(SEM) in conjunction with energy-dispersive X-ray spectroscopy(EdS), and optical microscopy. The results reveal that each stream possesses its own unique compositional features. Carbonate minerals associated with calcite and dolomite, followed by quartz, remain the major minerals in both the ROM and tails streams. In the ROM stream, chalcopyrite appears to occur as veins within the carbonatite-hosting ore body. Mineral phase mutation was discovered in the tails stream because magnetite formerly identified in the ROM as the primary iron oxide had evolved into hematite. This metamorphosis was likely promoted by the concentration process. The concentration process was effective, upgrading the chalcopyrite content from 2 wt% in the ROM stream to 58 wt% in the concentrate stream; it was accompanied by bornite(4 wt%), anilite(3 wt%), and digenite(2.5 wt%). In addition, the concentrate stream exhibited properties distinctive from those of the other streams. The FTIR analysis showed the existence of a sulfide group related to the chalcopyrite mineral. Free chalcopyrite grains were observed in the concentrate by SEM analysis, and their mineral presence was supported by the EdS analysis results. All characterization techniques corresponded well with each other regarding the structure, chemistry, and composition of the samples.

关键词： chalcopyrite mineral characterization phase mutation concentrate streams

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稳定性氢同位素分析在牛肉产地溯源中的应用

分析化学 2009年第9期37卷 1333-1336页

作者：郭波莉魏益民 Kelly d.simon 潘家荣魏帅中国农业科学院农产品加工研究所/农业部农产品加工与质量控制重点实验室 Institute of Food Research Norwich

探讨了利用高温热解炉和同位素比率质谱仪(IRMS)联用测定肉品中稳定性氢同位素比率的方法,并利用此方法测定了我国不同地域来源脱脂牛肉、牛尾毛中氢同位素比率。分析了牛组织中氢同位素组成与地域经度、纬度及海拔高度变化的关系,以及... 详细信息

探讨了利用高温热解炉和同位素比率质谱仪(IRMS)联用测定肉品中稳定性氢同位素比率的方法,并利用此方法测定了我国不同地域来源脱脂牛肉、牛尾毛中氢同位素比率。分析了牛组织中氢同位素组成与地域经度、纬度及海拔高度变化的关系,以及稳定性氢同位素用于牛肉产地溯源的可行性。结果表明,不同地域来源牛组织中δ2H值的差异显著,其与当地饮水中氢同位素组成密切相关,而且有随着地理纬度增加而减小的趋势;牛尾毛与牛肉中δ2H值的相关性显著。稳定性氢同位素是用于牛肉产地溯源的一项很有潜力的指标,且牛肉和牛尾毛中的氢同位素组成均可反映牛来源地的信息。

关键词：牛肉产地溯源稳定性氢同位素

Assessing the Impact of Social Media on Tourism destination decision Making among Foreign Students in China

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Assessing the Impact of Social Media on Tourism Destination ...

作者： AGYAPONG elvis 中南林业科技大学

学位级别：硕士

China is growing drastically with tourism industry which is helping to boast the nation's economy and enhancing *** thesis looked into the importance of social media,which has an involvement in *** social media as a pivot which plays an important role in the fast-growing tourism and hospitality *** media provides ample opportunity for adverts,bookings,payment,feedback,and sharing of social *** study evaluated social media impact on tourism destination amongst foreign students in China through questionnaire *** show that foreign students rely on social media platforms to make important tourism related decisions amongst other *** main aim of this study is to assess the impact of social media on tourism destination decision-making by foreign students in *** of the limitless capabilities that social media provides,it is gradually transforming diverse business *** Uses and Gratification theory,a quantitative research approach was used to achieve the sole of the present study on some selected Province Universities where foreign universities students are *** doing so,Partial Least Square and Structural Equation Modeling and SPSS statistical software were used in processing the valid responses(272).The findings of the study revealed that all eight proposed hypotheses were significantly having a positive relationship with tourism destination *** means that social media in the 21st century largely contribute to tourists' decision-making within the fraternity of *** study offers several implications for theory and *** paper takes the foreign students in China as the research *** foreign students in China in this study indicated that tourists can quickly acquire information about a destination and make bookings with relative ***,all the foreign students in China in this study specified that social media increase tourist

关键词： Social media foreign students tourism tourism destination travel decision making

Sulforaphane as a Promising Natural Molecule for Cancer Prevention and Treatment

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Current Medical Science 2021年第2期41卷 250-269页

作者： Osama A.Elkashty simon d.Tran McGill Craniofacial Tissue Engineering and Stem Cells Laboratory Faculty of DentistryMcGill UniversityMontreal H3A 0G4Canada department of Oral Pathology Faculty of DentistryMansoura UniversityMansoura 35516Egypt

Tumorigenicity-inhibiting compounds have been identifled in our daily *** example,isothiocyanates(ITCs)found in cruciferous vegetables were reported to have potent cancer=prevention *** best characterized ITC is sulforaphane(SF).SF can simultaneously modulate multiple cellular targets involved in carcinogenesis,including(1)modulating carcinogen-metabolizing enzymes and blocking the action of mutagens;(2)inhibition of cell proliferation and induction of apoptosis;and(3)inhibition of neo-angiogenesis and *** targets cancer stem cells through modulation of nuclear factor kappa B(NF-κB),Sonic hedgehog(SHH),epithelial-mesenchymal transition,and Wnt/βcatenin *** chemotherapy/SF combination was tested in several studies and resulted in favorable *** its favorable toxicological profile,SF is a promising agent in cancer prevention and/or *** this article,we discuss the human metabolism of SF and its effects on cancer prevention,treatment,and targeting cancer stem cells,as well as providing a brief review of recent human clinical trials on SF.

关键词： sulforaphane isothiocyanates cancer chemoprevention antineoplastic agent

TCF7L2 rs7903146 polymorphism is associated with gastric cancer: a case-control study in the Venezuelan population

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World Journal of Gastroenterology 2016年第28期22卷 6520-6526页

作者： Keila Torres Luis Labrador elvis Valderrama Miguel Angel Chiurillo Laboratorio de Genetica Molecular 'dr. Jorge Yunis-Turbay' Decanato de Ciencias de la Salud Universidad Centroccidental Lisandro Alvarado Barquisimeto 3001 Venezuela Postgrado en Ciencias Biologicas Departamento de Biologia Celular Universidad Simon Bolivar Caracas 1081-A Venezuela departamento de Anatomia Patologia Hospital Antonio Maria Pineda-UCLA Barquisimeto 3001 Venezuela departamento de Patologia Clinica Universidade Estadual de Campinas Campinas 13083 Sao Paulo Brazil

AIM: To explore the association between TCF7L2 rs12255372 and rs7903146 single nucleotide polymorphisms (SNPs) and gastric cancer risk in Venezuelan ***: We performed a case-control study including 122 paraffin-embedded archived intestinal-type gastric cancer samples and 129 biopsies obtained by superior endoscopy from chronic gastritis patients. Gastric cancer samples were classified according the degree of carcinoma differentiation. Genomic dNA was extracted from tissues, and the two SNPs of TCF7L2 gene (rs12255372 and rs7903146) were genotyped by polymerase chain reaction-restriction fragment length polymorphism reactions. Multiple regression analysis with adjustments for age and gender were performed and best-fitting models of inheritance were determined. Statistic powers were post-hoc ***: After adjusting for age and sex the TCF7L2 rs7903146 TT genotype was associated with gastric cancer risk under the recessive genetic model (OR = 3.11, 95%CI: 1.22-7.92, P = 0.017). We further investigated the distribution of rs12255372 and rs7903146 genotypes according gastric cancer stratified by degree of differentiation, and we observed that carriers of rs7903146 T allele (CT + TT vs CC) had a significantly increased risk of moderate/well differentiated gastric cancer (dominant model, OR = 2.55, 95%CI: 1.35-4.80, P = 0.004), whereas the rs7903146 TT genotype was associated with poorly differentiated gastric cancer in the recessive model (OR = 3.65, 95%CI: 1.25-10.62, P = 0.018). We did not find association between rs12255372 SNP and the susceptibility of developing gastric ***: TCF7L2 rs7903146 polymorphism is associated with gastric cancer risk in the Venezuelan population, and could be related to determine the degree of differentiation of tumor cells.

关键词： Gastric cancer Wnt/β -catenin pathway TCF7L2 Single nucleotide polymorphism Genetic susceptibility

Optimal harvesting for a single-species population governed by Gompertz law:Influence of environmental fluctuation and limited harvesting capacity

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International Journal of Biomathematics 2019年第2期12卷 115-142页

作者： P.d.N.Srinivasu simon d.Zawka Sri Sathya Sai University for Human Excellence Navanihala Village Okali PostKamalapur Taluk Gulbarga DistrictKarnataka 585313India department of Mathematics Andhra University Visakhapatnam 530003India department of Mathematics Ar ba Minch University Arba MinchEthiopia

This work presents an optimal harvesting problem associated with a single-species population governed by Gompertz law in a seasonally fluctuating *** influence of environmental fluctuation is accommodated by choosing the coefficients in the differential equation to be periodic functions with the same period and restriction on the harvesting effort is accommodated by considering binding constraints on the control ***,a linear optimal control problem has been considered where the state dynamics is governed by Gompertz equation and the control variable is subject to the binding *** the help of maximum principle and the concept of blocked intervals,an optimal periodic solution has been obtained which is followed by the construe tion of optimal solution using the theory of most rapid *** results of the study are demonstrated through numerical simulations.

关键词： Optimal harvesting Gompertz equation seasonality binding constraint blocked intervals

Collembola communities and soil conditions in forest plantations established in an intensively managed agricultural area

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Journal of Forestry Research 2021年第5期32卷 1819-1832页

作者： István Harta Barbara simon Szergej Vinogradov dániel Winkler Institute of Environmental Science Szent István UniversityGödöllőHungary Institute of Methodology Szent István UniversityGödöllőHungary Institute of Wildlife Management and Vertebrate Zoology University of SopronSopronHungary

The challenges of a changing climate have directed greater attention to afforestation,but the effects of afforestation on soil fertility and soil biota have not been fully *** explore changes in the soil conditions in two 20-year-old forest plantations established in formerly intensively fertilized plots of agricultural land,we focused on the current developmental state of the sites that received the most fertilizer and evaluated soil properties and Collembola(springtails)*** oak(Quercus petraea)and black locust(Robinia pseudoacacia)that had been planted in the afforestation sites were assessed for differences between plantations of native and invasive *** adjacent reference associations,including forests and open habitats,were also analyzed and *** showed that the soils in the two afforested sites were similar in their properties and Collembola communities to those of the control cultivated forests,but differed from each other in pH,calcium,phosphorus,and ammonium *** available potassium and phosphorus contents in the soil of the sessile oak plantation were still high,while the soil organic matter content was adequate(SOM>2.0%)in both *** richness of Collembola ranged from 18 in the cultivated arable land to 43 in the relict *** a few species typical for forests(e.g.,Neanura muscorum,Isotomiella minor,Entomobrya muscorum)were detected in the young plantations,while species characteristic of open habitats(e.g.,Protaphorura campata,Lepidocyrtus cyaneus)occurred as *** more individuals and species of Collembola were present in the soil of young plantations than in arable fields,their community diversities were significantly lower compared to the control forest *** community diversity differed significantly also between the two plantation types(with native and non-native tree species).Mean abundance in the afforested sites was about 2.5 times higher than in the cultiv

关键词： Afforestation diversity Fertilizers Soil fauna Soil properties Springtails

Modified shear cell for characterization of the rheological behavior of particulate networks under compression

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Particuology 2020年第4期18卷 1-9页

作者： simon Hammerich Anthony d.Stickland Benjamin Radel Marco Gleiss Hermann Nirschl Institute of Mechanical Process Engineering and Mechanics Karlsruhe Institute for Technology(KIT)Strasse am Forum 876131 KarlsruheGermany Particulate Fluids Processing Centre Department of Chemical EngineeringThe University of Melbourne3010Australia

Knowledge of the rheological behavior of saturated particulate networks is crucial for every process in which a particulate network is built-up,dewatered,or transported,as in a decanter ***,difficulties arise as to how to characterize the material *** far,no standardized method or measurement device has *** this work,the requirements for a useful device are discussed,followed by the design of a modified shear cell for a Schulze ring shear tester *** and its measurement *** experiments under normal load with different sediments consisting of inorganic and organic particles whose material properties strongly affect the rheological behavior were *** results demonstrate the potential of the modified shear ***,current challenges in characterization are *** characterization possibilities of the developed shear cell are a further step toward understanding the theological behavior of liquid-saturated particulate networks.

关键词： Sediment rheology Saturated particulate network Shear cell Shear compression Rheological behavior

Nest predators, nest-site selection and nest success of the Emei Shan Liocichla(Liocichla omeiensis), a vulnerable babbler endemic to southwestern China

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Chinese Birds 2016年第3期7卷 161-166页

作者： Yiqiang Fu Benping Chen simon d.dowell Zhengwang Zhang Sichuan Institute Key Laboratory for Protecting Endangered Birds in the Southwest Mountains College of Life Sciences Leshan Normal University Laojunshan National Nature Reserve Administration North of England Zoological Society Chester Zoo Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering College of Life Sciences Beijing Normal University

Background: The Emei Shan Liocichla(Liocichla omeiensis) is a globally vulnerable babbler, endemic to southwestern China. We investigated its nest predators, nest-site selection and nest success at the Laojunshan National Nature Reserve in Sichuan, China in order to identify the precise nesting-habitat requirements of the species, and to test whether the nest-site-selection cues, preferred by the Emei Shan Liocichla, are positively associated with nest ***: We used infrared cameras to determine nest predators. We compared the microhabitat attributes between nest and random sites, as well as successful and failed nests. We used Binary Logistic Regression to determine the most important variables affecting nest-site selection of the Emei Shan Liocichla. We used the nest survival analysis in Program MARK to estimate daily nest survival rates(dSR). Nest success was calculated using the Mayfield ***: In total 56 nests were found. The dSR for all nests that contained at least one egg was 0.9564 ± 0.0091(95 % CI 0.9346–0.9711)(n = 40), while the total nest success was 27.5 %. We identified four categories of predators in 10 nest predation events, i.e. squirrels(n = 5), snakes(n = 3), raptors(n = 1) and wasps(n = 1). We found that:(1) nest predation was the primary reason for nest failure of the Emei Shan Liocichla,(2) tree cover, bamboo cover, liana abundance and distance to forest edge or gap were the most important variables affecting nest-site selection of this species, and(3) the nest-site-selection variables we measured appeared not to be positively associated with nest ***: Our findings suggest that the Emei Shan Liocichla tended to select nest sites near forest edges or gaps with good concealment and that nest-site selection by this species was nonrandom but not necessarily adaptive. Reducing forest-edge development and protecting bamboo stands should be effective for conservation of this species.

关键词： Nest predator Nest-site selection Nest success Liocichla omeiensis Laojunshan Nature Reserve