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Exploring the synthesis conditions to control the morphology of gold-iron oxide heterostructures

Nano Research 2019年第8期12卷 1781-1788页

作者： Pablo Tancredi Luelc Souza da Costa Sebastian Calderon Oscar Moscoso-Londono Leandro M. Socolovsky Paulo J. Ferreira diego muraca Daniela Zanchet Marcelo Knobel Laboratory of Amorphous Solids INTECINFaculty of EngineeringUniversity of Buenos Aires - CONICETBuenos AiresCP C1063ACVArgentina Department of Inorganic Chemistry Institute of ChemistryUniversity of Campinas (UNICAMP)CP615413083-970CampinasSPBrazil Brazilian Nanotechnology National Laboratory (LNNano) Rua Giuseppe Maximo Scolfaro 10000CampinasSPBrazil International Iberian Nanotechnology Laboratory (INL) Av. Mestre Jose Veiga s/n4715-330 BragaPortugal “Gleb Wataghin” Institute of Physics University of Campinas (UNICAMP)CEP 13083-859CampinasSPBrazil Autonomous University of Manizales Antigua Estacion del FerrocarrilManizalesCP 170001Colombia Facultad Regional Santa Cruz Universidad Tecnoldgica Nacional - CIT Santa Cruz (CONICET)- Av delos Inmigrantes 555Rio GallegosSanta CruzArgentina Materials Science and Engineering Program The University of Texas at AustinAustinTexas 78712USA

Gold-iron oxide nano-heterostructures with a clear and well-defined morphology were prepared via a seed-assisted method. The synthesis process and the events of heterogeneous nucleation during the decomposition of the iron precursor were carefully studied in order to understand the mechanism of the reaction and to tailor the architecture of the fabricated heterostructures. When employing Au seeds of 3 and 5 nm, nanoparticles with a dimer-like morphology were produced due to the occurrence of a single iron oxide nucleation event. Otherwise, multi-nucleation events could be favored by two mechanisms:(i) by the incorporation of a reducing agent and the slowing down of the heating protocol, leading to a core-shell system;(ii) by the increase of the Au seed size to 8 nm, leading to a flower-like system. Further increase of the Au seed size to 12 nm using similar synthesis conditions promotes the homogeneous nucleation and growth of the iron oxide phase, without formation of heterostructures. An in-depth study was performed on the gold-iron oxide heterostructures to confirm the epitaxial growth of the oxide domain over the Au seed and to analyze the elemental distribution of the components within the heterostructures. Finally, it was found that the modification of the plasmonic properties of the Au nanoparticles are strongly influenced by the architecture of the heterostructure, with a more pronounced damping effect for the systems produced after multi-nucleation events.

关键词： nanoparticles gold-iron oxide heterostructures heterogeneous nucleation epitaxial growth HR-microscopy

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MINIMIZING EXCITATION LIGHT LEAKAGE AND MAXIMIZING MEASUREMENT SENSITIVITY FOR MOLECULAR IMAGING WITH NEAR-INFRARED FLUORESCENCE

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Journal of Innovative Optical Health Sciences 2011年第3期4卷 301-307页

作者： BANGHE ZHU EVA M.SEVICK-muraca Center for Molecular Imaging The Brown Foundation Institute of Molecular Medicine The University of Texas Health Science Center at Houston Houston TX 77030USA

Near-infraredfluorescence(NIRF)imaging involves the separation of weakfluorescence signals from backscattered excitation *** measurement sensitivity of current NIRF imaging systems is limited by the excitation light leakage through *** this contribution,the authors demonstrate that the excitation light leakage can be suppressed upon using appropriatefilter combination and *** excitation light leakage and measurement sensitivity were assessed and compared in this study by computing the transmission ratios of excitation to emission light collected and the signal-to-noise ratios in well-controlled phantom studies with differentfilter combinations and *** appropriatefilter combinations and permutations,we observe as much as two orders of magnitude reduction in the transmission ratio and higher signal-to-noise ratio.

关键词： Molecular imaging fluorescence opticalfilter excitation light leakage noise floor

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Effect of Heat Loss on Laminar Flamelet Species Concentration

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Journal of Thermal Science 2016年第5期25卷 418-423页

作者： Marco Boccanera diego Lentini Dipartimento di Ingegneria Meccanica e Aerospaziale Sapienza Università di Roma

The effects of heat loss on the structure of laminar flamelets,which are the constitutive elements of turbulent flames under the most common operating conditions,are investigated for typical aeronautical gas-turbine operating conditions at *** magnitude of heat loss is quantified via the "enthalpy defect" measured with respect to an adiabatic flame.A procedure to generate laminar flamelets with an assigned enthalpy defect at the boundaries is devised and applied to nonpremixed propane/air flames,as propane reproduces the essential features of higher hydrocarbon *** is found,contrary to commonly held beliefs,that the enthalpy defect has a significant effect on the concentration not only of minor species,but also of main reaction *** effects are found in general to be more pronounced for fuel-rich *** impact is anticipated on the formation rate of nitric *** effects of scalar dissipation rate are also discussed.

关键词： Turbulent Combustion Heat Transfer Laminar Flamelets Hydrocarbon Combustion Aeroengines Gas Turbines

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Nerve growth factor catches copper in neuronal inning

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Neural Regeneration Research 2020年第4期15卷 665-666页

作者： diego La Mendola Department of Pharmacy University of Pisa

The physiological effect of neurotrophic factors and their role in Alzheimer’s disease(AD):Neurotrophins(NTs)are a family of homologues proteins that play an essential role in neuronal cells growth,survival and *** proteins include the nerve growth factor(NGF),the brain derived neurotrophic factor(BDNF),NT-3 and NT-3,also known as NT-4/5.

关键词： Alzheimer copper differentiation.

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Two methodological approaches to assess the seismic vulnerability of masonry bridges

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Journal of Traffic and Transportation Engineering(English Edition) 2019年第1期6卷 49-64页

作者： diego Maria Barbieri Department of Civil and Environmental Engineering Norwegian University of Science and Technology Department of Civil Constructional and Environmental Engineering Sapienza University of Rome

This work describes the seismic vulnerability assessment of a railway masonry arch *** conservation state is initially investigated by means of a thorough field and laboratory test campaign, comprising destructive and non-destructive tests. Two different methods are used to evaluate the bridge seismic vulnerability. The first method adopts a deterministic approach and corresponds to a single non-linear static analysis, performed as described in the Eurocodes. The second method employs a probabilistic approach and considers the variability of the involved mechanical parameters(structure geometry and properties of the building materials) and seismic parameters(intensity of the action and site conditions). This method associates the probabilistic values of ground acceleration exceedance to the estimated seismic vulnerability. This is shown by means of fragility curves, which allow to take into consideration the uncertainty of the various components involved in the definition of the seismic vulnerability and display the seismic damage scenarios. Currently no code requires to perform this calculation procedure. In addition,this work compares the values of masonry mechanical properties specified in the Eurocodes with those obtained in an extensive investigation campaign involving more than one hundred masonry bridges. Compressive strength and longitudinal elasticity modulus are the relevant mechanical parameters investigated. The outcomes of this research can contribute to the development of a more efficient maintenance system of the masonry bridges belonging to the railway network. This has an important role when it comes to establishing the priority order of assets intervention.

关键词： Railway masonry arch bridge Bridge maintenance and conservation Masonry mechanical parameters Non-linear static analysis Seismic fragility Finite element analysis

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Preclinical characterization and validation of a dual-labeled trastuzumab-based imaging agent for diagnosing breast cancer

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Chinese Journal of Cancer Research 2015年第1期27卷 74-82页

作者： Xuejuan Wang Melissa B. Aldrich Milton V. Marshall Eva M. Sevick-muraca Department of Nuclear Medicine Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education) Peking University Cancer Hospital & Institute Division of Molecular Imaging The Brown Foundation Institute of Molecular Medicine University of Texas Health Science Center at Houston

Objective： The combination of both nuclear and fluorescent reporters provides unique opportunities for noninvasive nuclear imaging with subsequent fluorescence image-guided resection and pathology. Our objective was to synthesize and optimize a dual-labeled trastuzumab-based imaging agent that can be used to validate an optical imaging agent with potential use in identifying tumor metastases in human epidermal growth factor receptor 2 （HER2） positive breast cancer patients. Methods： [111In]-DTPA-trastuzumab-IRDye 800 was synthesized by a three-step procedure. Purity, stability, immunoreactivity, internalization and biodistribution were explored in HER2＋ SKBR-3 cells. Biodistribution of [111In]-DTPA-trastuzumab-IRDye 800 was performed in a SKBR-3 xenograft model. Results： [111In]-DTPA-trastuzumab-IRDye 800 demonstrated high purity by both chemical and fluorometric determinations. Both flow cytometry and the Lindmo assay demonstrated a high binding affinity of [111In]-DTPA-trastuzumab-IRDye 800 to HER2-overexpressing cells. The dual-labeled conjugate was stable in PBS, but not in serum after 24 h at 37 ℃. Larger molecules （〉150 kD） were seen after a 24 h-incubation in human serum. Biodistribution studies revealed tumor-specific accumulation of [111In]-DTPA- trastuzumab-IRDye 800 in SKBR-3 tumors, and tumor uptakes at 24 and 48 h were （12.42±1.72）% and （9.96±1.05） %, respectively, following intravenous administration. The tumor-to-muscle ratio was 9.13±1.68 at 24 h, and increased to 12.79±2.13 at 48 h. Liver and kidney showed marked uptake of the dual-labeled imaging agent. Conclusions： [111In]-DTPA-trastuzumab-IRDye 800 is an effective diagnostic biomarker that can be used to validate dual-labeled, molecularly targeted imaging agents and can allow these agents to be translated into clinical practice for identifying HER2＋ lesions.

关键词： Dual-labeling trastuzumab human epidermal growth factor receptor 2 (HER2) near-infrared opticalimaging (NIR optical imaging) radioimmunoscintigraphy

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Orbit orientation in didelphid marsupials （Didelphimorphia： Didelphidae）

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Current Zoology 2017年第4期63卷 403-415页

作者： Patricia PILATTI diego ASTUA Laboratorio de Mastozoologia Departamento de Zoologia Universidade Federal de Pernambuco. Av. Prof. Moraes Rego S/N Cidade Universitaria Recife PE 50670-901 Brazil

Usually considered a morphologically conservative group, didelphid marsupials present consider- able variation in ecology and body size, some of which were shown to relate to morphological structures. Thus, changes on orbit morphology are likely and could be related to that variation. We calculated orbit orientation in 873 specimens of 16 Didelphidae genera yielding estimates of orbits convergence （their position relative to midsagittal line） and verticality （their position relative to frontal plane）. We then compared similarities in these variables across taxa to ecological, morpho- logical and phylogenetic data to evaluate the influencing factors on orbit orientation in didelphids. We found an inverse relation between convergence and verticality. Didelphids orbits have low ver- ticality but are highly convergent, yet orbit orientation differs significantly between taxa, and that variation is related to morphological aspects of the cranium. Rostral variables are the only morpho- logical features correlated with orbit orientation： increasing snout length yields more convergent orbits, whereas increase on snout breadth imply in more vertical orbits. Size and encephalization quotients are uncorrelated with orbit orientation. Among ecological data, diet showed significant correlation whereas locomotion is the factor that less affects the position of orbits. Phylogeny is uncorrelated to any orbital parameters measured. Ecological factors seemingly play a more import- ant role on orbit orientation than previously expected, and differentiation on orbit orientation seems to be more functional than inherited. Thus, despite the apparent homogeneity on didelphid morphology, there is subtle morphological variability that may be directly related to feeding behavior.

关键词： convergence Didelphidae frontation orbit orientation verticality.

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An Integrated Approach for Optimal Design of Micro Gas Turbine Combustors

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Journal of Thermal Science 2009年第2期18卷 173-184页

作者： Luca Fuligno diego Micheli Carlo Poloni EnginSoft s.p.a. Dipartimento di Ingegneria Meccanica Universita degli Studi di Trieste Dipartimento

The present work presents an approach for the optimized design of small gas turbine combustors, that integrates a0-D code, CFD analyses and an advanced game theory multi-objective optimization algorithm. The output of the0-D code is a baseline design of the combustor, given the required fuel characteristics, the basic geometry (tubularor annular) and the combustion concept (i.e. lean premixed primary zone or diffusive processes). For the optimizationof the baseline design a simplified parametric CAD/mesher model is then defined and submitted to a CFDcode. Free parameters of the optimization process are position and size of the liner hole arrays, their total area andthe shape of the exit duct, while different objectives are the minimization of NOx emissions, pressure losses andcombustor exit Pattern Factor. A 3D simulation of the optimized geometry completes the design procedure. As afirst demonstrative example, the integrated design process was applied to a tubular combustion chamber with alean premixed primary zone for a recuperative methane-fuelled small gas turbine of the 100 kW class.

关键词： micro gas turbine combustor optimized design

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Correlation of powder flow properties to interparticle interactions at ambient and high temperatures

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Particuology 2014年第1期12卷 90-99页

作者： Igino Tomasetta diego Barletta Massimo Poletto Dipartimento di Ingegneria Industriale Università degli Studi di Salerno

A combination of a continuum approach and a particleparticle approach to describe the multiscale nature of the mechanical properties of bulk solids may be beneficial to scientific and engineering applica tions. In this paper, a procedure is proposed to estimate the interparticle forces beginning with the bulk flow properties as measured with standardized techniques. In particular, the relationship between inter particle forces and bulk solid tensile strength is adopted based on the microscale approaches of Rumpf （1970） and Molerus （1975）. The flow properties of fluid cracking catalyst （FCC）, corundum and glass bead powders were all characterized with a modified Schulze ring shear cell capable of operating at tempera tures up to 500 ~C. The powder test conditions were selected such that the van der Waals forces were the most significant particleparticle interactions. The model equations describe two cases, in which either elastic or plastic deformation of the contact points is assumed. The results indicate that the model pro vides the correct order of magnitude for the values of the tensile strength when proper values for the mean curvature radius at the contact points are taken into account. A sensitivity analysis for the main parameters in the model was performed. This analysis indicated that the assumption of plastic deforma tion at contact surfaces coupled with a decrease in porosity justified an increase of the tensile strength with consolidation stress. Furthermore, the effect of temperature on the measured flow behavior can be explained as a change in the strength of the material.

关键词： Shear testingYield locusvan der Waals forcelnterparticle interactionsPowder consolidationHigh temperature

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A comparison between powder flow property testers

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Particuology 2017年第3期15卷 10-20页

作者： Hamid Salehi diego Barletta Massimo Poletto Dipartimento di lngegneria lndustriale Universita degli Studi di Salerno Via Giovanni Paolo II 132 84084 Fisciano SA Italy

In this work, three different shear testers-the Jenike shear cell tester, the Schulze ring shear tester, and the Brookfield powder flow tester-were compared in terms of the raw shear stress time series, yield loci points, angle of internal friction, cohesion, and unconfined yield strength. The three different powders of dolomitic lime, calcium lactate, and calcium carbonate were used for these comparisons. These three powders were characterized into different flowability classes using the ]enike classification, wherein dolomitic lime falls into the cohesive range, calcium lactate falls into the free-flowing range, and calcium carbonate falls into the very cohesive range. Results showed that the best agreement between the testers was found with moderately cohesive powders such as dolomitic lime. Furthermore, the free-flowing material tends to produce more consistent data between the three testers in terms of shear stresses and yield loci. It should be noted that the pre-shear data of free-flowing powder obtained by the Jenike shear cell must be appropriately interpreted. The largest differences between the testers are found with calcium carbonate, which is a highly compressible powder. The ways in which a high powder compressibility can differently affect the results obtained with the different testers were discussed.

关键词： Powder flow property Shear tester Flowability Jenike tester Schulze tester Brookfield powder flow tester

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