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Ractopamine up take by alfalfa (medicago sativa) and wheat (Triticum aestivum) from soil

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Journal of Environmental Sciences 2015年第8期27卷 86-92页

作者： Weilin l.Shelver Thomas m.DeSutter USDA-ARS Biosciences Research laboratory Department of Soil Science North Dakota State University

Ractopamine is a beta adrenergic agonist used as a growth promoter in swine, cattle and turkeys. To test whether ractopamine has the potential to accumulate in plants grown in contaminated soil, a greenhouse study was conducted with alfalfa（medicago sativa） and wheat（Triticum aestivum） grown in two soils having different concentrations of organic matter（1.3% and 2.1%）, amended with 0, 0.5, and 10 μg/g of ractopamine. Plant growth ranged from 2.7 to 8.8 g dry weight（dw） for alfalfa, and 8.7 to 40 g dw for wheat and was generally greater in the higher organic matter content soil. The uptake of ractopamine in plant tissues ranged from non-detectable to 897 ng/g and was strongly dependent on soil ractopamine concentration across soil and plant tissue. When adjusted to the total fortified quantities, the amount of ractopamine taken up by the plant tissue was low, 〈 0.01% for either soil.

关键词： Ractopamine Plant uptake Environment Foodsafety

Do concentrations in eggs and liver tissue tell the same story of temporal trends of mercury in high Arctic seabirds?

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Journal of Environmental Sciences 2018年第6期30卷 65-72页

作者： mark l.mallory Birgit m.Braune Biology Department Acadia University Environment and Climate Change Canada National Wildlife Research Centre Carleton University

mercury（Hg） remains a key contaminant of concern in Arctic biota, and monitoring of Hg concentrations in seabird tissues will be an effective approach to track the effects of implementing the minamata Convention. We examined trends in total Hg（THg） in liver and egg tissues of two Arctic seabirds, thick-billed murres（Uria lomvia） and northern fulmars（Fulmarus glacialis）, between 1976 and 2013 to assess whether both tissues showed similar patterns of Hg change. Hepatic THg was consistently higher than egg THg, and both species had similar egg THg concentrations, but fulmars had higher hepatic THg than *** THg concentrations showed more relative variation through time than *** suggest that egg THg better reflects exposure of birds to THg in local, Arctic prey,whereas liver THg may incorporate longer term, year-round THg exposure. Additional analysis of THg distribution in Arctic seabirds post-laying would help inform interpretation of long-term trends.

关键词： Canada Fulmarus glacialis Northern fulmar Thick-billed murre Uria lomvia

Spent coffee grounds as a renewable source of energy: An analysis of bulk powder flowability

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Particuology 2019年第2期17卷 92-100页

作者： l. massaro Sousa m.C. Ferreira Drying Center for Pastes Suspensions and Seeds. Chemical Engineering Department Federal University of Sao Carlos. P.O. Box 676 13565-905 Sao Carlos Brazil

The main use for spent coffee grounds (SCG) produced in the soluble coffee industry is thermal energy generation in the industry itself. The SCG are processed using operations that are strongly dependent on powder flow behavior. In this study, we evaluated two classical flowability in dices of non-consolidated SCG powders: the angle of repose (AoR), and the Hausner ratio (HR). The influences of the mean particle diameter, particle size distribution (PSD), and water content on the AoR and HR values of SCG were analyzed for powders with a mean particle size range of 225-550 μm. For powders with a mean particle size close to 350 μm and for mixtures containing more than 40% fine particles, the HR (>1.35) and AoR (>45 °) values were characteristic of poor flowability. The AoR was sensitive to the powder PSD, and powders with similar mean particle sizes had higher AoR values when the PSD was larger. For powders w让h water contents up to 50%, the flowability indices were not greatly affected by the water content. A modified linear-mixture packing model was used to predict the packed bed void fractions for binary and ternary mixtures of the three base powders. The model was used to construct a ternary diagram to estimate the HR values of the mixtures. An equation was fitted to correlate HR and AoR. The proposed diagram and the equation provide insight into flow behavior and could be used for process design of industrial plants that handle SCG.

关键词： Spent coffee ground Biomass Flowability Hausner ratio Angle of repose

DNS in evolution of vorticity and sign relationship in wake transition of a circular cylinder:(pure)mode A

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Acta mechanica Sinica 2019年第6期35卷 1131-1149页

作者： l.m.lin Z.R.Tan Key laboratory for mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Navigation Wuhan University of TechnologyWuhan 430063China Hubei Key laboratory of Inland Shipping Technology Wuhan University of TechnologyWuhan 430063China

In the present paper,the spatio-temporal evolution of vorticity in the first wake instability,i.e.,(pure)mode A,is investigated in order to understand the wake vortex dynamics and sign relationships among vorticity *** numerical simulation(DNS)for the flow past a circular cylinder is performed,typically at a Reynolds number of 200,in the three-dimensional(3-D)wake *** to characteristics of time histories of fluid forces,three different stages are identified as the computational transition,the initial stage and fully developed *** the second initial stage,the original two-dimensional spanwise vortices become obviously three-dimensional associated with the streamwise or vertical vorticity intensified up to about *** a matter of fact,these additional vorticities,caused by the intrinsic 3-D instability,are already generated firstly on cylinder surfaces early in the computational transition,indicating that the three-dimensionality appeared early near the *** evolution of additional components of vorticity with features the same as mode A shows that(pure)mode A can be already formed in the late computational *** careful analysis of the vorticity field on the front surface,in the shear layers and near wake at typical times,two sign laws are *** illustrate intrinsic relationships among three vorticity components,irrelevant to the wavelength or Fourier mode and Reynolds number in(pure)mode *** importantly,the origin of streamwise vortices is found and explained by a new physical mechanism based on the theory of vortex-induced *** a result,the whole process of formation and shedding vortices with these vorticities is firstly and completely *** characteristics are presented in detail.

关键词： Wake transition Circular cylinder Vorticity mode A Sign law

mechanical stress and deformation analyses of pressurized cylindrical shells based on a higher-order modeling

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Defence Technology（防务技术） 2023年第2期20卷 24-33页

作者： S.mannani l.Collini m.Arefi Department of Solid mechanic Faculty of Mechanical EngineeringUniversity of KashanKashan87317-51167Iran Department of Engineering and Architecture University of ParmaParco Area Delle Scienze 181/A43124ParmaItaly

In this research,mechanical stress,static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are *** kinematic relations are developed based on higherorder sinusoidal shear deformation *** stretching formulation is accounted for more accurate *** total transverse deflection is divided into bending,shear and thickness stretching parts in which the third term is responsible for change of deflection along the thickness *** axisymmetric formulations are derived through principle of virtual work.A parametric study is presented to investigate variation of stress and strain components along the thickness and longitudinal *** explore effect of thickness stretching model on the static results,a comparison between the present results with the available results of literature is *** an important output,effect of micro-scale parameter is studied on the static stress and strain distribution.

关键词： Principle of virtual work Thickness-stretched and shear deformable model Stress and strain analyses Cylindrical pressure vessel

Cr（V）involvementin the toxicity pathway of testicular damage

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Asian Journal of Andrology 2002年第2期4卷 153-155页

作者： m.l.Pereira T.m.Santos 等 DepartmentofBiology Departmentofchemistry UniversityofAveriro3810－193AveiroPortugal

Aim: The functional integrity of the blood-testis barrier (BTB) in male mice exposed to Cr(V) was studied in order to clarify the mechanism underlying testicular injury. methods: Adult male mice were subcutaneously injected repeated doses of 8.02 mmol (0.5 ml) of Cr/*** for 5 days. Animals receiving a similar volume of bis(hydroxyethyl)-aminotris(hydroxymethyl)methane buffer (BT) were used as controls. The animals were sacrificed on day 6 and small fragments of seminiferous tubules, approximately 8-10 mm length, were incised and sutured at both ends. They were exposed in vitro to horseradish peroxidase-containing culture medium for 10 minutes. Tissues were then fixed and processed for ultrastructural studies. Results: Controls and Cr(V)-treated group resulted in the uptake of the tracer by Sertoli cells. However, the major finding consisted in the permeability of the BTB only in the Cr(V)-group, as evidenced by the presence of the tracer within the junctions between the neighbouring Sertoli cells. Conclusion: The BTB is disrupted in mice submitted to Cr(V). The permeability of the BTB is a crucial feature to be investigated for the understanding of lesions within the seminiferous tubule.

关键词： Blood-testis barrier Cr(V) Horseradish peroxidase Integrity Spermatogenesis

Numerical modelling Point-to-Plane of Negative Corona Discharge in N_2 Under Non-Uniform Electric Field

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Plasma Science and Technology 2015年第6期17卷 469-474页

作者： A.K.FEROUANI m.lEmERINI l.mERAD m.HOUAlEF Ecole Préparatoire en Sciences et Techniques Département de Physique lPT Université A.BelkaidFaculté des SciencesDépartement de Physique Ecole Préparatoire en Sciences et Techniques Département de Maths

The paper presents a simulation model of the negative corona discharge in N2 under various pressures. The simulated discharge is of a negative point-to-plane mass type, with an inter-electrode separation distance of 20 mm and a symmetry about the axis of discharge. This simulation investigates the behavior of the neutral density and temperature for different pressures in the range of 0.1-10.0 bar. The spatial and temporal evolution of the neutral gas is analyzed based upon the equations of continuity, momentum and energy in a two-dimensional cylindrical geometry model. For that geometry of the system, the FCT （Flux Corrected Transport） technique was adopted. The results show that the pressure plays a significant role of the neutrals dynamics.

关键词： DC corona discharge FCT method numerical simulation

Colloidal(Gd0.98Nd0.02)2O3 nanothermometers operating in a cell culture medium within the first and second biological windows

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Journal of Rare Earths 2020年第5期38卷 483-491页

作者： m.l.Debasu H.Oliveira J.Rocha l.D.Carlos Department of Physics CICECO-Aveiro Institute of MaterilsUniversidade de Aveiro3810-193AveiroPortugal Department of Chemistry CICECO-Aveiro Institute of MaterialsUniversidade de Aveiro3810-193AveiroPortugal Department of Biology CESAMLaboratory of Biotechnology and CytomicsUniversidade de Aveiro3810-193AveiroPortugal

Non-contact,self-referenced and near-infrared luminescent nanothermometers have been recognized as emerging tools in the fields of nanomedicine and nanotechnology due to their great capability of precise temperature readout at the nanoscale and real-time deep-tissue ***,the development of multifunctional and biocompatible luminescent nanothermometers operating within the optically transparent biological windows with high thermal sensitivity(>2.0%/K)remains ***,we present(Gd0.98Nd0.02)2O3 nanothermometers operated effectively within the first and second biological windows upon continuous-wave laser diode excitation at 808 *** thermometric parameters are defined by the relative changes in the emission intensities originating from the two Stark components of the 4 F3/2 level(R2 and R1)to the 4 I9/2(900-1000 nm),4 I11/2(1035-1155 nm)and 4 I13/2(1300-1450 nm)*** thermo metric parameters are evaluated for colloidal samples in a cell culture medium and powder samples,and the highest thermal sensitivity(2.18%/K at 298 K)is attained for the former in the first biological window(both the excitation and emission in the 800-965 nm range).The repeatability and temperature uncertainty are 99%and 1.2 K,*** nanothermometers are biocompatible with human mNT-1 melanoma and HaCaT cells for 24 h of exposure and nanoparticle concentration up to 0.400 mg/ml,showing their potential for applications in nanomedicine,e.g.,intracellular imaging and temperature mapping.

关键词： Gd2O3 Nd3^+-doped nanoparticles luminescent nanothermometry Thermal sensitivity Cytotoxicity of nanoparticles Rare earths

Resistance of full-scale beams against close-in *** modeling and field tests

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Defence Technology（防务技术） 2024年第10期40卷 35-47页

作者： A.Prado A.Alañón R.Castedo A.P.Santos l.m.lópez m.Chiquito m.Bermejo C.Oggeri Escuela Politécnica Superior dé Avila Universidad de SalamancaÁvila05003Spain E.T.S.I.minas y Energía Universidad Politecnica de MadridMadrid28003Spain Department of Engineering Aviation and TechnologySaint Louis UniversityMadrid28003Spain Department of Environment Land and Infrastructure Engineering(DIATI)Politecnico di TorinoTorino10129Italy

This paper explores the performances of a finite element simulation including four concrete models applied to a full-scale reinforced concrete beam subjected to blast loading. Field test data has been used to compare model results for each case. The numerical modelling has been, carried out using the suitable code lS-DYNA. This code integrates blast load routine(CONWEP) for the explosive description and four different material models for the concrete including: Karagozian & Case Concrete, Winfrith, Continuous Surface Cap model and Riedel-Hiermaier-Thoma models, with concrete meshing based on 10, 15, and 20 mm. Six full-scale beams were tested: four of them used for the initial calibration of the numerical model and two more tests at lower scaled distances. For calibration, field data obtained employing pressure and accelerometers transducers were compared with the results derived from the numerical simulation. Damage surfaces and the shape of rupture in the beams have been used as references for comparison. Influence of the meshing on accelerations has been put in evidence and for some models the shape and size of the damage in the beams produced maximum differences around 15%. In all cases, the variations between material and mesh models are shown and discussed.

关键词： Blast test Numerical simulation lS-DYNA Concrete model mesh effect Full-scale beams