2,390 research outputs found

    Circular dichroism simulated spectra of chiral gold nanoclusters: A dipole approximation

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    Circular dichroism (CD) spectra of chiral bare and thiol-passivated gold nanoclusters have been calculated within the dipole approximation. The calculated CD spectra show features that allow us to distinguish between clusters with different indexes of chirality. The main factor responsible of the differences in the CD lineshapes is the distribution of interatomic distances that characterize the chiral cluster geometry. These results provide theoretical support for the quantification of chirality and its measurement, using the CD lineshapes of chiral metal nanoclusters.Comment: 3 pages + 4 figure

    Soil pollution assessment in the Baia Mare area after partial closure of ore processing activities

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    The paper presents the assessment of the soil pollution with Cu, Pb and Zn in the Baia Mare area, historically polluted with metals resulted from mining and processing of non-ferrous ores. Despite the closure of mines and reducing the activity related to ore processing, Baia Mare is still a highly polluted site with Pb, Cu and Zn. The Tessier extraction scheme carried out on soil samples recently collected revealed the residual fraction as dominant for all three metals, followed by the reducible fraction bound to Fe and Mn oxides. The exchangeable fraction, considered as the most mobile fraction and that bound to carbonates, which can be mobilized under acidic conditions, were lower. The presence of the oxidisable metal fraction was also observed

    Three-Dimensional (3D) Printed Microneedles for Microencapsulated Cell Extrusion

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    Cell-hydrogel based therapies offer great promise for wound healing. The specific aim of this study was to assess the viability of human hepatocellular carcinoma (HepG2) cells immobilized in atomized alginate capsules (3.5% (w/v) alginate, d = 225 µm ± 24.5 µm) post-extrusion through a three-dimensional (3D) printed methacrylate-based custom hollow microneedle assembly (circular array of 13 conical frusta) fabricated using stereolithography. With a jetting reliability of 80%, the solvent-sterilized device with a root mean square roughness of 158 nm at the extrusion nozzle tip (d = 325 μm) was operated at a flowrate of 12 mL/min. There was no significant difference between the viability of the sheared and control samples for extrusion times of 2 h (p = 0.14, α = 0.05) and 24 h (p = 0.5, α = 0.05) post-atomization. Factoring the increase in extrusion yield from 21.2% to 56.4% attributed to hydrogel bioerosion quantifiable by a loss in resilience from 5470 (J/m3) to 3250 (J/m3), there was no significant difference in percentage relative payload (p = 0.2628, α = 0.05) when extrusion occurred 24 h (12.2 ± 4.9%) when compared to 2 h (9.9 ± 2.8%) post-atomization. Results from this paper highlight the feasibility of encapsulated cell extrusion, specifically protection from shear, through a hollow microneedle assembly reported for the first time in literature

    Perception of Sunflecks by the UV-B Photoreceptor UV RESISTANCE LOCUS8

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    Sunflecks, transient patches of light that penetrate through gaps in the canopy and transiently interrupt shade, are eco-physiologically and agriculturally important sources of energy for carbon gain, but our molecular understanding of how plant organs perceive and respond to sunflecks through photoreceptors remains limited. The UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8) is a recent addition to the list of plant photosensory receptors, and we have made considerable advances in our understanding of the physiology and molecular mechanisms of action of UVR8 and its signaling pathway. However, the function of UVR8 in the natural environment is poorly understood. Here, we show that the UVR8 dimer/monomer ratio responds quantitatively and reversibly to the intensity of sunflecks that interrupt shade in the field. Sunflecks reduced hypocotyl growth and increased CHALCONE SYNTHASE (CHS) and ELONGATED HYPOCOTYL5 gene expression and CHS protein abundance in wild-type Arabidopsis (Arabidopsis thaliana) seedlings, but the uvr8 mutant was impaired in these responses. UVR8 was also required for normal nuclear dynamics of CONSTITUTIVELY PHOTOMORPHOGENIC1. We propose that UVR8 plays an important role in the plant perception of and response to sunflecks.Fil: Moriconi, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Binkert, Melanie. Universidad de Ginebra; SuizaFil: Costigliolo Rojas, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Sellaro, Romina Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Ulm, Roman. Universidad de Ginebra. Facultad de Ciencias; SuizaFil: Casal, Jorge José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

    CodeWeave: Exploring Fine-Grained Mobility of Code

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    This paper explores the range of constructs and issues facing the designer of mobile code systems which allow for the unit of mobility to be finer-grained than that of execution. Mobile UNITY, a notation and proof logic for mobile computing, provides for this research a clean abstract setting, i.e., unconstrained by compilation and performance considerations traditionally associated with programming language design. Within the context of Mobile UNITY, we take the extreme view that every line of code and every variable declaration is potentially mobile, i.e., it may be duplicated and/or moved from one program contxt to another on the same host or across the network. We also assume that complex code systems may move with equal ease. The result is CodeWeave, a model for abstract exploration of new forms of code mobility prior to their integration into programming systems and middleware

    REMOVAL OF CU2+ IONS FROM AQUEOUS SOLUTIONS USING NANNOCHLOROPSIS OCULATA BIOMASS

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    The aim of this study was to investigate the capacity of Nannochloropsis oculata biomass for Cu2+ ions removal from aqueous solutions. The initial concentrations of Cu2+ ions used to determine the maximum amount of Cu2+ ions adsorbed onto Nannochloropsis oculata biomass varied from 10 mg/L to 50 mg/L. The experimental data were analysed using Langmuir, Freundlich, and Dubinin-Radushkevisch isotherm models. The correlation regression coefficients show that the biosorption process can be well defined by the Langmuir equation.  From the Dubinin-Radushkevich isotherm the mean free energy was calculated to be 10 kJ/mol, which indicates that Cu2+ ions biosorption is characterized by a chemical process

    Wood - a renewable resource for production of sugar and biofuel

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    Albies Alba wood samples were subjected to autohydrolysis extraction at different severities (180, 190 and 200°C), delignification with sodium chloride, and acid hydrolysis of pretreated and delignified substrates. After autohydrolysis pre-treatment under selected operation conditions, cellulose and lignin, in solid phases, and liquors containing hemicellulose products (monosaccharides, oligosaccharides and inhibitory compounds) have been obtained. The purpose of this study is to obtain glucose by autohydrolysis, delignification and acid hydrolysis of fir wood. Fir wood was pretreated at 180, 190 and 200 °C for 5, 10 and 15 minutes, followed by delignification with sodium chloride and acid hydrolysis. The acid hydrolysis of pretreated material and pretreated-delignified material was hydrolyzed using H2SO4 in two stages of impregnation with acid. The results show that elimination of hemicellulose by autohydrolysis pretreatment and lignin by delignification method improve acid hydrolysis yield
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