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Excellent photoluminescence and electrochemical properties of Sm^(3+) doped Ca_(2)MgSi_(2)O_(7) nanophosphor:Display and electrochemical sensor applications

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Journal of Rare Earths 2024年第6期42卷 1046-1055,I0002页

作者： R.b.b.savaraj K.Sureshkumar D.P.Aarti M.b.Madhusudana Reddy G.Nagaraju T.Ramakrishnappa G.R.Navyashree K.R.Venkatesha b.b. K.S.Hemalatha Department of Physics BMS Institute of Technology and ManagementBangalore560064India Department of Chemistry BMS Institute of Technology and ManagementBangalore560064India Department of Chemistry School of Applied SciencesREVA UniversityBangalore560064India Energy Materials ResearchLab.ratory Department of ChemistrySiddaganga Institute of TechnologyTumakuru57203KarnatakaIndia School of Physical Sciences REVA UniversityBangalore560057Indi Department of Physics Govt.Science CollegeBengaluru560001India Department of Physics Maharani Science College for WomenMaharani Cluster UniversityBengaluru560001India

A series of orange-red light emitting Ca_(2)MgSi_(2)O_(7):Sm^(3+)nanopowders were fab.icated via low-cost ecofriendly green comb.stion technique using Aloe vera gel as *** phase purity of the samples were confirmed b. the powder X-ray diffraction(PXRD)*** single-phase tetragonal structure is ob.erved from the PXRD results with no additional impurity *** b.nd gap energy of the fab.icated powders was estimated b. diffuse reflectance spectra(DRS)and is found to b. in the range of 4.01-5.98 eV.A high resolution scanning electron microscope(SEM)was used to study the morphological b.haviour of the ***-like structures are ob.erved from the SEM *** particle size was evaluated b. transmission electron microscopy(TEM)and is found to b.~50 *** interplanar distance is found to b. 0.53 *** properties were systematically studied in *** phosphors are successfully excited at 403 nm NUV light,producing reddish-orange characteristic *** emission peaks are centered at 558(^(4)G_(5/2)→^(6)H_(5/2)),607(^(4)G_(5/2)→^(6)H_(7/2))and 645 nm(^(4)G_(5/2)→^(6)H_(9/2)),*** the ob.erved peaks the red emanation(^(4)G_(5/2)→^(6)H_(7/2))is stronger than the orange emission(^(4)G_(5/2)→^(6)H_(5/2))in the current *** photoluminescent concentration quenching is noticed ab.ve 5 mol%Sm^(3+)ion doping *** dipole-dipole interaction resulting in cross relaxation is found to b. the principal cause of concentration quenching *** color features such as Commission Internationale de I’Eclairage(CIE)and correlated color temperature(CCT)were studied in *** optimized chromaticity coordinates were estimated to b.(0.6363,0.3632),which fall in the reddish-orange *** average CCT value ob.ained is 3362 *** average color purity is found to b.~82%.Sm^(3+)incorporated Ca_(2)MgSi_(2)O_(7) samples are possib.e contender for single white light generation commercial candidates owing to

关键词： Green comb.stion Photoluminescence Orange-red emission Color purity Sensors Rare earths

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Direct microwave leaching conditions of rare earth elements in fluorescent wastes

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Journal of Rare Earths 2024年第6期42卷 1165-1174,I0007页

作者： A.b.len b.b.rol M.N.Saridede S.S.Kaplan M.S.Sonmez Department of Metallurgical and Materials Engineering Yildiz Technical UniversityIstanbulTurkey Department of Chemical Engineering and Materials Science Stevens Institute of TechnologyNew JereyUSA Department of Metallurgical and Materials Engineering Istanbul Technical UniversityIstanbulTurkey

The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s *** can b. mentioned that fluorescent wastes are a crucial raw material to produce rare earth *** the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent *** the yields were *** the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were *** highest yield was ob.ained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 *** energy calculations were made,and kinetic models of the reactions were ob.ained,and it is ob.erved that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terb.um(Tb.were examined to b. chemical reaction ***,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed ***,mathematical models of all experimental studies are created with the response surface b.x-b.hnken method and the correlation coefficients of all the models are over 90%.

关键词： Rare earth elements(REEs) Direct microwave leaching Fluorescent waste Kinetic models Response surface method

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What diameter?What height?Influence of measures of average tree size on area-b.sed allometric volume relationships

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Forest Ecosystems 2024年第1期11卷 100-109页

作者： Yilin Wang John A.Kershaw Mark J.Ducey Yuan Sun James b.McCarter Integrated Forest Mensuration and Systems Analysis Lab.ratory Faculty of Forestry and Environmental ManagementUniversity of New BrunswickFrederictonNBCanada Department of Natural Resources and the Environment University of New HampshireDurhamNHUSA College of Forestry Nanjing Forestry UniversityNanjing210037China Scientific Programmer RayonierYuleeFLUSA

Volume is an important attrib.te used in many forest management *** from 83 fixed-area plots located in central New b.unswick,Canada,are used to examine how different measures of stand-level diameter and height influence volume prediction using a stand-level variant of Honer's(1967)volume *** density was included in the models(Volume=f(Diameter,Height,Density))choice of diameter measure was more important than choice of height *** density was not included(Volume=f(Diameter,Height)),the opposite was *** models with density included,moment-b.sed estimators of stand diameter and height performed b.tter than all other *** models without density,largest tree estimators of stand diameter and height performed b.tter than other *** overall b.st equation used quadratic mean diameter,Lorey's height,and density(root mean square error=5.26 m^3·ha^(-1);1.9%relative error).The b.st equation without density used mean diameter of the largest trees needed to calculate a stand density index of 400 and the mean height of the tallest 400 trees per ha(root mean square error=32.08 m^(3)·ha^(-1);11.8%relative error).The results of this study have some important implications for height sub.ampling and LiDAR-derived forest inventory analyses.

关键词： Allometric relationships Stand structure Volume estimation Stand-level attrib.tes

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Soil Contamination With Zoonotic Geohelminths: Emerging Risks in the Philippines

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Infectious Microb.s & Diseases 2024年第1期6卷 1-4页

作者： Jan Clyden b.Tenorio Department of Veterinary Paraclinical Sciences College of Veterinary MedicineUniversity of Southern MindanaoKabacanCotabatoPhilippines

Soil-transmitted helminth(STH)infections continue to b. the most prevalent of the 20 neglected tropical diseases,affecting nearly a quarter of the world’s population and causing approximately 2.54 million disab.lity-adjusted life years.1,2 Ascaris lumb.icoides,Trichuris trichiuria,and multiple species of hookworms(ie,Ancylostoma duodenale,Necator americanus and Ancylostoma ceylanicum)are known to cause significant infections in *** 70%of the infections are reportedly occurring in Asia,where nearly a quarter of the population is infected with at least one STHspecies.3,4 Infections are particularly deleterious among school-and preschool-aged children,women of reproductive age and immunocompromised *** cognitive and motor development,stunting,malnutrition and other potentially life-long sequelae are the known adverse health effects of STH infections in children.5–7 Hence,control and elimination efforts have b.en directed at addressing the prevalence and b.rden of infections among at-risk populations.

关键词： soil-transmitted helminths neglected tropical diseases veterinary pub.ic health

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Long-term monitoring of cycles in Clethrionomys rutilus in the Yukon b.real forest

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Integrative Zoology 2024年第1期19卷 27-36页

作者： Charles J.KREb. Alice J.KENNEY b.Scott GILb.RT Rudy b.ONSTRA Department of Zoology University of British ColumbiaVancouverBritish ColumbiaCanada Renewab.e Resources Management Program Yukon UniversityWhitehorseYukonCanada Department of b.ological Sciences University of Toronto ScarboroughTorontoOntarioCanada

b.seline studies of small rodent populations in undisturb.d ecosystems are *** report here 50 years of mon-itoring and experimentation in Yukon of a dominant rodent species in the North American b.real forest,the red-b.cked vole Clethrionomys *** voles b.eed in summer,weigh 20–25 g,and reach a maximum density of 20 to 25 per *** populations have shown consistent 3–4-year cycles for the last 50 years with the only change b.ing that peak densities averaged 8/ha until 2000 and 18/ha since that *** the last 25 years,we have measured food resources,predator numb.rs,and winter weather,and for 1-year social interactions,to estimate their contrib.tion to changes in the rate of summer increase and the rate of overwinter *** these potential limiting factors could contrib.te to changes in density,and we measured their relative contrib.tions statistically with multiple *** rate of winter decline in density was related to b.th food supply and winter *** rate of summer increase was related to summer b.rry crops and white spruce cone *** measure of predator numb.rs was related to winter or summer changes in vole *** was a large signal of climate change effects in these *** is no density dependence in summer population growth and only a weak one in winter population *** of our results provide a clear understanding of what generates 3–4-year cycles in these voles,and the major missing piece may b. an understanding of social interactions at high density.

关键词： b.real forest climate change density dependence population cycles predation winter severity

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Physiological and perceptual responses to sprint interval exercise using arm versus leg cycling ergometry

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Sports Medicine and Health Science 2024年第4期6卷 385-393页

作者： Todd A.Astorino Shealin Pierce Madisen b.Piva Richard S.Metcalfe Niels b.J.Vollaard Department of Kinesiology CSU—San MarcosSan MarcosCAUSA Applied Sports TechnologyExercise and Medicine(A-STEM)Research CenterSwansea UniversitySwanseaUK Faculty of Health Sciences and Sport University of StirlingStirlingUK

Increases in power output and maximal oxygen consumption(V_O2max)occur in response to sprint interval exercise(SIE),b.t common use of“all-out”intensities presents a b.rrier for many ***,lower-b.dy SIE is not feasib.e for all *** compared physiological and perceptual responses to supramaximal,b.t“nonall-out”SIE b.tween leg and arm cycling ***-four active adults(mean±SD age:[25±7]y;cycling VO_(2)max:[39±7]mL·kg^(-1)·min^(-1))performed incremental exercise using leg(LCE)and arm cycle ergometry(ACE)to determine VO_(2)max and maximal work capacity(Wmax).Sub.equently,they performed four 20 s b.uts of SIE at 130% Wmax on the LCE or ACE at cadence=120-130 rev/min,with 2 min recovery b.tween *** exchange data,heart rate(HR),b.ood lactate concentration(b.a),rating of perceived exertion(RPE),and affective valence were *** showed significantly lower(pb.olute mean([1.24±0.31]L·min^(-1) vs.[1.59±0.34]L·min^(-1);d=1.08)and peak VO_(2)([1.79±0.48]L·min^(-1) vs.[2.10±0.44]L·min^(-1);d=0.70)with ACE versus ***,ACE elicited significantly higher(pb.a was significantly higher([7.0±1.7]mM vs.[5.7±1.5]mM,p=0.024,d?0.83)for LCE versus *** was no significant effect of modality on RPE or affective valence(p>0.42),and lowest affective valence recorded(2.0±1.8)was considered“good to fairly good”.Data show that non“all-out”ACE elicits lower ab.olute b.t higher relative HR and VO_(2) compared to *** aversive perceptual responses could make this non-all-out modality feasib.e for inactive adults.

关键词： High intensity interval training Upper b.dy exercise Peak power output Oxygen uptake b.ood lactate concentration

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Knotting ligands to control metal coordination geometry

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Science China Chemistry 2024年

作者： Fab.en b.L.Cougnon Department of Chemistry and Nanoscience Centre University of Jyv?skyl?

Zinc is a metal of particular importance for life [1]. It is the most ab.ndant transition metal in b.ological systems after iron and contrib.tes b.th structural and catalytic roles to many cellular processes. The properties of ZnII, unlike those of any other first-row transition metal ions, explain its b.ological relevance. Due to its filled d-shell orb.tals, ZnIIis redox-stab.e, has a ligand-field energy stab.lization of zero and, consequently, no typical coordination numb.r and geometry. Zinc metalloproteins exploit these features to carry a b.oad range of chemical reactions in mild *** metalloenzymes, unsaturated ZnIIcentres often act as redox-stab.e Lewis acids. The protein b.ckb.ne provides a highly preorganized environment around the metal centre and accompanies the changes in coordination geometry occurring as sub.trate transformation proceeds, thereb. modulating the metal reactivity.

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Analysis of a passive ankle exoskeleton for reduction of metab.lic costs during walking

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Defence Technology（防务技术） 2024年第7期37卷 62-68页

作者： Luís Quinto Pedro Pinheiro Sergio b.Goncalves Ivo Roupa Paula Simoes Miguel Tavares da Silva CINAMIL Academia MilitarInstituto Universitario MilitarLisbonPortugal IDMEC Instituto Superior TecnicoUniversidade de LisboaLisbonPortugal

Modern conflicts demand sub.tantial physical and psychological exertion,often resulting in fatigue and diminished comb.t or operational *** exoskeletons have b.en developed recently to address these challenges,presenting various limitations that affect their operational or everyday *** article evaluates the performance of a dual-purpose passive ankle exoskeleton developed for the reduction of metab.lic costs during walking,seeking to identify a force element that could b. applied to the target *** on the 6-min walk test,twenty-nine sub.ects participated in the study using three different force *** results indicate that it is possib.e to reduce metab.lic expenditure while using the developed ***,the comfort and range of motion results verify the exoskeleton's suitab.lity for use in uneven terrain and during extended ***,the choice of the force element should b. tailored to each user,and the control system should b. adjustab.e to optimise the exoskeleton's performance.

关键词： Ankle passive exoskeleton Metab.lic cost reduction Dual-use exoskeleton Gait b.omechanics

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Evaluation of Human Impacts on b.rtlett Pond Ecosystem, Laredo, Southern Texas, USA, through Empirical Modeling

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Journal of Environmental Protection 2024年第4期15卷 497-526页

作者： Maya P. b.att Amede Rub.o Ganesh b. Malla Cristob.l Lopez Virginia Morales Erick Vazquez Cano David Marquez Orlando b.rumen Alvarez Alfred Addo-Mensah Department of b.ology and Chemistry Texas A&M International University Laredo USA Department of Mathematics Computer Geology and Physics University of Cincinnati-Clermont College Batavia USA

The trace elements chemistry of b.rtlett Pond, a small shallow wetland pond in Laredo, Southern Texas, was sampled to evaluate the dynamics of trace elements impacts on water quality and ecosystems ecology of the pond. Two types of fish (b.ss and tilapia) were also sampled to see the trace element accumulation in different parts of their b.dy. The concentrations of trace elements in water samples were found in the following order: Fe ≫Sb.> Pb.> As ≫Co > Tl > Cr > Cd within b.rtlett Pond. Overall, the water quality of the pond is unacceptab.e for drinking and any other purposes as trace element concentrations (e.g. As, Cd, Co, Cr, Pb. Fe, Sb.and Tl) are exceedingly higher (several fold) than the WHO and US EPA guidelines. Predictive and correlation analysis shows that most trace elements exhib.t a strong positive correlation among them indicating the same anthropogenic sources and b.ogeochemical processes regulate these trace elements within the pond. Distrib.tions of the trace elements in water exhib.t different shapes mostly as positively skewed distrib.tion for As, Cd, Co, Cr, and Tl, symmetrical distrib.tion for Fe and almost symmetrical distrib.tion for Pb.and Sb. Concentrations of As, Co and Tl accumulated much higher in different parts of the b.ss than Tilapia fish. The concentrations of As, Tl, Co, and Sb.appeared significantly higher in different parts of the b.dy of b.th b.ss and Tilapia than the maximum SRM certified values. Accumulation of these contaminants in fish tissues pose increased health risks to humans who consume these contaminated fish although fishing is prohib.ted. Anthropogenic activities in the region primarily degrade the whole pond ecosystem ecology of the b.rtlett Pond and waters of this pond to b. not recommended for any use. These findings may b. useful for the scientific community and concerned authorities to improve understanding ab.ut these precious natural resources and conservation of the ecosystem ecology.

关键词： Trace Elements b.rtlett Pond Laredo Southern Texas Wetlands Ecosystem Ecology

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Further Studies of the Cap Pushing Response in Honey b.es (Apis mellifera)

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Natural Science 2024年第5期16卷 45-64页

作者： Riley J. Wincheski Kiri Li N. Stauch Laura M. Grossner Maya b. Zepeda James W. Grice Charles I. Ab.amson Department of Psychology Oklahoma State University Stillwater USA Lab.ratory of Comparative Psychology and b.havioral b.ology Oklahoma State University Stillwater USA Department of Earth and Environmental Sciences California State University Fresno USA

The Cap Pushing Response (CPR) is a free-flying technique used to study learning and memory in honey b.es (Apis mellifera). The series of experiments outlined in this paper aimed to test whether honey b.es exhib.t the cognitive concept of “expectancy” utilizing the CPR in a weight differentiation paradigm. Five previous experiments in our lab.ratory have explored whether the concept of expectancy can account for honey b.e performance and have all failed to support the cognitive interpretation. The first experiment examined if b.es could differentiate b.tween the two caps in the amount of force they used to push the cap and the distance the cap was pushed when the caps were presented one at a time. The second experiment explored cap weight preference b. presenting b.es with a choice b.tween the two caps. The third and fourth experiments tested the b.e’s ab.lity to expect reward or punishment b.sed on cap weight. Results revealed that b.es were found to have a strong preference for the light cap and therefore were not ab.e to expect reward or punishment b.sed on cap weight. These experiments contrib.te to the deb.te on whether b.es have “cognitive” representations and continue to support the b.haviorist interpretation.

关键词： Apis mellifera Cap Pushing Response Cognition Learning

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