17 research outputs found

    Evidence of a cubic iron sub-lattice in t-CuFe2O4 demonstrated by X-ray Absorption Fine Structure

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    Copper ferrite, belonging to the wide and technologically relevant class of spinel ferrites, was grown in the form of t-CuFe2O4 nanocrystals within a porous matrix of silica in the form of either an aerogel or a xerogel, and com-pared to a bulk sample. Extended X-ray absorption fine structure (EXAFS) spectroscopy revealed the presence of two different sub-lattices within the crystal structure of t-CuFe2O4, one tetragonal and one cubic, defined by the Cu2+ and Fe3+ ions respectively. Our investigation provides evidence that the Jahn-Teller distortion, which occurs on the Cu2+ ions located in octahedral sites, does not affect the coordination geometry of the Fe3+ ions, regardless of their location in octahedral or tetrahedral sites

    Involvement of multiple aluminium exclusion mechanisms in aluminium tolerance in wheat

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    The goal of this study was to determine if Al-chelators other than malate are released from root apices and are involved in Al-tolerance in different wheat (Triticum aestivum L.) genotypes. Also we wanted to establish if root exudates contribute to increases in rhizosphere pH around the root tip. In seedlings of Al-tolerant Atlas, we have documented a constitutive phosphate exudation from the root apex. Because phosphate can complex Al and bind protons, it could play an important role in Al tolerance, both via complexation of Al3+ and by contributing to the alkalinization of rhizosphere pH observed at the apex of Atlas. This study suggests that in wheat, Al-tolerance can be mediated by multiple exclusion mechanisms controlled by different genes

    Crystallization behaviour of TiO2−ZrO2TiO_{2}-ZrO_{2} composite nanoparticles

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    To investigate tumor vascularity by dual source volume perfusion computed tomography (VPCT) in advanced lung adenocarcinoma with positive EGFR-mutant and determine whether any of the VPCT parameters would predict the tumor response to gefitinib.Twelve patients (5 males and 7 females, Median age: 53 years, range: 36 - 69 years) with advanced lung adenocarcinoma received VPCT scan. All patients with positive EGFR-mutant were confirmed by pathological biopsy. After a 6-week therapy of gefitinib, VPCT was repeated and the short-term effect evaluated by the RECIST criteria. The VPCT parameters (blood volume, blood flow and permeability surface) of 12 patients were compared with their differentiation grade and short-term effect.Short-term effects were poor in those cases in whom BF increased after a 6-week of targeted therapy (P = 0.030). BF and PS at pre-therapy were negatively correlated with differentiation grade (r = -0.603, -0.694, P = 0.038, 0.012). There was a negative correlation between the rate of BF decline and differentiation grade (r = -0.686, P = 0.029); a negative correlation existed between the trend of BF and RECIST criteria (r = -0.707, P = 0.010). But there was no significant correlation with differentiation grade (P = 0.059). If the BF decline was considered effective, the dual source VPCT could predict the effect of RECIST criteria. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of VPCT was 100%, 66.7%, 83.3%, 75% and 100% respectively.Dual source VPCT of advanced lung adenocarcinoma can assess effectively tumor vascularity and perfusion changes after the therapy of gefitinib. It is important in evaluating the response of targeted therapy in lung cancer

    IDEA: interface dynamics and energetics algorithm

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    IDEA, interface dynamics and energetics algorithm, was implemented, in FORTRAN, under different operating systems to mimic dynamics and energetics of elementary events involved in interfacial processes. The code included a parallel elaboration scheme in which both the stochastic and the deterministic components, involved in the developed physical model, worked simultaneously. IDEA also embodied an optionally running VISUAL subroutine, showing the dynamic energy changes caused by the surface events, e.g., occurring at the gas-solid interface. Monte Carlo and ordinary differential equation system subroutines were employed in a synergistic way to drive the occurrence of the elementary events and to manage the implied energy flows, respectively. Biphase processes, namely isothermal and isobaric adsorption of carbon monoxide on nickel, palladium, and platinum surfaces, were first studied to test the capability of the code in modeling real frames. On the whole, the simulated results showed that IDEA could reproduce the inner characteristics of the studied systems and predict properties not yet experimentally investigated

    Do root exudates exert more influence on rhizosphere bacterial community structure than other rhizodeposits?

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    Root exudates are credited with having a major influence on the structure of rhizosphere bacterial communities. However, evidence indicates that direct influence of root exudates on bacterial communities is limited to small spatiotemporal windows surrounding root apices. Furthermore, root exudates are modified upon assimilation by microorganisms, prior to rerelease into the rhizosphere. Also, many of the compounds that dominate root exudates are ubiquitous in the rhizosphere and arise from microbial metabolites and rhizodeposits other than exudates. Consequently, rhizosphere carbon pools associated with regions of roots other than apices are unlikely to be dominated by root exudates. Thus, it is important to consider all carbon pools in the rhizosphere as potential drivers of microbial community structure. This has implications for the distribution of rhizosphere bacteria and should factor as an important consideration in the development of effective strategies for managing beneficial plant-microbe interactions
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