1,346 research outputs found

    Autoradiographic Study of the Turnover of Chromatin-Associated Phospholipids in Vicia Faba L.

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    SUMMARYAutoradiographic data from labelling studies on the incorporation of [14C] ethanolamine into nuclear phospholipids of meristem cells from roots of Vicia faba indicated the presence of a continuous labelling pattern for the nuclear membrane throughout the cell cycle. In contrast, a periodic labelling pattern was observed in chromatin of interphase nuclei which closely paralleled the synthesis pattern for DNA. This corroborated biochemical data from previously published studies of hepatocyte nuclear membranes and chromatin

    Life Products of Stars

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    We attempt to document complete energetic transactions of stars in their life. We calculate photon and neutrino energies that are produced from stars in their each phase of evolution from 1 to 8 M_sun, using the state-of-the-art stellar evolution code, tracing the evolution continuously from pre-main sequence gravitational contraction to white dwarfs. We also catalogue gravitational and thermal energies and helium, and heavier elements that are stored in stars and those ejected into interstellar space in each evolutionary phase.Comment: 26 pages, including 8 figures and 3 tables. Submitted to ApJ

    Improvement of EAF efficiency through an integrated control of scrap melting and slag characteristics

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    Several innovations have been introduced into the EAF system during the last decades. The improvementof energy efficiency and production rates are probably related to a correct integration of the different systemsand to a correct design of the scrap charges as a function of the production rate, of the metal lossesand of the energy consumption that are considered an optimal compromise to fulfil a correct economicbalance for the melting, decarburation and dephosphoration operation. In order to achieve the aim of anenergetic advanced model has been developed through the integration of the energy model of electric andchemical sources with the ones treating the metal bath oxidation and the foaming behaviour of the slags

    INFLUENCE OF THE THERMO-MECHANICAL PROCESSES ON THE FORMATION OF THICK CYLINDRICAL COMPONENTS FORMED BY DIFFERENT TECHNOLOGIES: HOT ROLLING, COLD BENDING, FORGING.

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    The production of thick cylinders in steels covers a significant role for the production of pressure vessels andother components applied in energy and chemical applications. The thermo-mechanical process performedon the products strongly affects the final properties, because the induced crystallographic textures are verydifferent. In the case of hot rolled and forging the forming operation takes place at high temperature but theinduced deformation pattern is very different. In the three points cold bending operation the cold deformationis associated with annealing processes which produce other crystallographic patterns and the relatedmechanical anisotropy. In this study a critical evaluation of the features and properties of the final productsobtained through these different technological routes has been realized

    Progressive Dysphasic Dementia with Bucco-Facial Apraxia: A Case Report

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    A patient with progressive dementia, prominent non-fluent aphasia and signs of frontal lobe involvement, was evaluated by neuropsychological testing, magnetic resonance imaging (MRI) and high resolution single photon emission tomography (SPET). The presence of severe bucco-facial apraxia, associated with spared imitation of limb movements, correlated well with a marked reduction of cerebral perfusion in the left fronto-temporal cortex. This case emphasizes the usefulness of SPET as a valuable alternative to PET for the diagnosis of conditions, such as progressive neuropsychological syndromes, where a coupled reduction of metabolism and blood flow can be expected

    Removal of metallic elements from real wastewater using zebra mussel bio-filtration process

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    The metallic element pollution is a serious environmental problem but still unsolved since these contaminants are released mainly by human activity, reaching all the environmental compartments. Traditional wastewater treatment plants are very efficient in removing metallic elements only when their concentration is in the order of mg/L, but are not able to remove them until \u3bcg/L, as it would be needed to cope with the water quality standards in low flow receptors. Therefore, the aim of our study was to evaluate the potential removal of some recalcitrant metallic elements to the classical treatments, by the natural process of bio-filtration performed by the invasive zebra mussel (Dreissena polymorpha). For this purpose we built a pilot-plant at the Milano-Nosedo wastewater treatment plant, where we placed about 40,000 D. polymorpha specimens appointed to the wastewater bio-filtration. The metallic element removal due to zebra mussel activity was evaluated in the treated wastewater with a plasma optical emission spectrometry (ICP-OES). Data obtained in these experiments showed an encouraging metallic element removal due to D. polymorpha activity; in particular, the total abatement (100%) of Cr after one day of bio-filtration exposure is remarkable. Therefore, this study encourages further research related with the use of bivalves as a new tool for the wastewater depuration process; in this regard, the contaminated mollusks used in the bio-filtration could be incinerated or stored in special landfills, as is also the case of traditional sewage sludge

    Intriguing C–H⋯Cu interactions in bis-(phenanthroline)Cu(I) redox mediators for dye-sensitized solar cells

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    We have synthesized and characterized a series of bis-(phenanthroline) Cu(I) complexes of interest as redox mediators for dye-sensitized solar cells. This study led to the discovery of intriguing anagostic interactions between the hydrogen atom and the copper center as evidenced by X-ray diffraction studies on a single crystal. Remarkably, an anagostic interaction was found between a H atom of a methyl group and a copper sit

    Wideband magnetic losses and their interpretation in HGO steel sheets

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    The magnetic properties of high-permeability grain-oriented (HGO) Fe-Si sheets have been investigated in the frequency range 1 Hz-10 kHz, with attention devoted to the role of thickness on the behavior of the magnetic losses and the phenomenology of skin effect. The study is focused on the wideband response of 0.174 mm and 0.289 mm thick sheets, comparatively tested at peak polarization values ranging between 0.25 T and 1.7 T. The experiments associate fluxmetric measurements with direct Kerr observations of the dynamics of the domain walls. A picture of the magnetization process comes to light, where the dynamics of the flux reversal takes hold under increasing frequencies through the motion of increasingly bowed 180 degrees walls, eventually merging at the sheet surface for a fraction of the semi-period. This effect can be consistently predicted, starting from the Kerrbased knowledge of the equilibrium wall spacing, by the numerical modeling of the motion of an extended array of 180 degrees domain walls, subjected to the balanced action of the applied and eddy current fields, and the elastic reaction of the bowed walls. This model can be incorporated into the general concept of loss separation, by calculating the classical loss component through the solution of the Maxwell's diffusion equation under a magnetic constitutive law identified with the normal DC curve. The numerical domain wall model and the loss decomposition consistently predict that the excess loss component, playing a major role in these grain-oriented materials at power frequencies, tends to disappear in the upper induction-frequency corner
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