Factores de riesgo y supervivencia libre de tumor en pacientes con trasplante renal de cadáver

[Background] There is an agreement in the fact that cancer incidence in transplant recipients increases at a rate disproportionately greater than in the general population. Several clinical studies have identified cancer risk factors, such as age, male gender, tobacco, UV radiation, viral infections, previous malignancies, intensity and duration of immunosuppressive therapies, HLA matches and time in waiting list.

Characterization of a putative grapevine Zn transporter, VvZIP3, suggests its involvement in early reproductive development in Vitis vinifera L

Gonzalez, E (reprint author), Univ Talca, Inst Biol Vegetal & Biotecnol, Talca, Chile.Background: Zinc (Zn) deficiency is one of the most widespread mineral nutritional problems that affect normal development in plants. Because Zn cannot passively diffuse across cell membranes, it must be transported into intracellular compartments for all biological processes where Zn is required. Several members of the Zinc-regulated transporters, Iron-regulated transporter-like Protein (ZIP) gene family have been characterized in plants, and have shown to be involved in metal uptake and transport. This study describes the first putative Zn transporter in grapevine. Unravelling its function may explain an important symptom of Zn deficiency in grapevines, which is the production of clusters with fewer and usually smaller berries than normal. Results: We identified and characterized a putative Zn transporter from berries of Vitis vinifera L., named VvZIP3. Compared to other members of the ZIP family identified in the Vitis vinifera L. genome, VvZIP3 is mainly expressed in reproductive tissue - specifically in developing flowers - which correlates with the high Zn accumulation in these organs. Contrary to this, the low expression of VvZIP3 in parthenocarpic berries shows a relationship with the lower Zn accumulation in this tissue than in normal seeded berries where its expression is induced by Zn. The predicted protein sequence indicates strong similarity with several members of the ZIP family from Arabidopsis thaliana and other species. Moreover, VvZIP3 complemented the growth defect of a yeast Zn-uptake mutant, ZHY3, and is localized in the plasma membrane of plant cells, suggesting that VvZIP3 has the function of a Zn uptake transporter. Conclusions: Our results suggest that VvZIP3 encodes a putative plasma membrane Zn transporter protein member of the ZIP gene family that might play a role in Zn uptake and distribution during the early reproductive development in Vitis vinifera L., indicating that the availability of this micronutrient may be relevant for reproductive development

Nanostructured Thermoelectric Chalcogenides

Thermoelectric materials are outstanding to transform temperature differences directly and reversibly into electrical voltage. Exploiting waste heat recovery as a source of power generation could help towards energy sustainability. Recently, the SnSe semiconductor was identified, in single-crystal form, as a mid-temperature thermoelectric material with record high figure of merit, high power factor and surprisingly low thermal conductivity. We describe the preparation of polycrystals of alloys of SnSe obtained by arc-melting; a rapid synthesis that results in strongly nanostructured samples with low thermal conductivity, advantageous for thermoelectricity, approaching the amorphous limit, around 0.3–0.5 W/mK. An initial screening of novel samples Sn1−xMxSe, by alloying with 3d and 4d transition metals such as M = Mn, Y, Ag, Mo, Cd or Au, provides for a means to optimize the power factor. M=Mo, Ag, with excellent values, are described in detail with characterization by x-ray powder diffraction (XRD), scanning electron microscopy (SEM), and electronic and thermal transport measurements. Rietveld analysis of XRD data demonstrates near-perfect stoichiometries of the above-mentioned alloys. SEM analysis shows stacking of nanosized sheets, with large surfaces parallel to layered slabs. An apparatus was developed for the simultaneous measurement of the Seebeck coefficient and electric conductivity at elevated temperatures

Structural evolution, optical gap and thermoelectric properties of CH3NH3SnBr3 hybrid perovskite, prepared by mechanochemistry

Direct bandgap semiconductors of the hybrid-perovskite family CH3NH3PbX3 (X = I, Br, Cl) exhibit outstanding light absorption properties and are the materials of choice for solar energy applications. As an alternative to poisonous Pb, tin-containing perovskites would show a lower effective mass thus exhibiting a higher charge carrier mobility. An auspicious candidate is CH3NH3SnBr3, with an estimated band gap of 1.902 eV, anticipating applications in photovoltaic devices for the visible to ultra-violet wavelength region. We describe that this perovskite can be prepared by ball milling in a straightforward way, yielding specimens with a superior crystallinity. A structural investigation from synchrotron X-ray powder diffraction (SXRD) data was essential to revisit the successive phase transitions this compound experiences down to 120 K, guided by specific heat capacity and DSC measurements. From the cubic structure identified at RT and 270 K, there is a gradual evolution of the patterns, analysed as a phase admixture between the cubic and the low-symmetry phase present at 160 K. This corresponds to an orthorhombic Pmc21 superstructure; this acentric space group enables polarization along the c-axis where there is a twofold screw axis, evidenced in the distribution of Sn-Br distances. Furthermore, there are two conspicuous changes in the orthorhombic framework, yet keeping the Pmc21 space group, which agree with the main calorimetric events (observed at 224 and 147 K). We interpret these changes as an interplay between the tilting of the SnBr6 octahedra of the inorganic framework and the breaking and reconstruction of H-bond interactions with the organic CH3NH+3 unit. The stereochemical effect of the lone electron pair of the Sn2+ ion is clear in the SnBr6 octahedral distortion. Diffuse reflectance UV/Vis spectroscopy yields an optical gap of ∼2.1 eV, in agreement with ab- initio calculations. A Seebeck coefficient of ∼2000 μV K-1 is determined near RT, which is one order of magnitude higher than those reported for other halide perovskites.Fil: Lopez, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; Argentina. Instituto de Ciencia de Materiales de Madrid; EspañaFil: Abia, Carmen. Institut Laue Langevin; Francia. Instituto de Ciencia de Materiales de Madrid; EspañaFil: Gainza, Javier. Instituto de Ciencia de Materiales de Madrid; EspañaFil: Kayser, Paula. Instituto de Ciencia de Materiales de Madrid; EspañaFil: Nemes, Norbert. Instituto de Ciencia de Materiales de Madrid; EspañaFil: Dura, Oscar J.. Universidad de Castilla-La Mancha; EspañaFil: Martinez, Jose L.. Instituto de Ciencia de Materiales de Madrid; EspañaFil: Fernandez Diaz, Maria Teresa. Institut Laue Langevin; FranciaFil: Alvarez Galvan, M. Consuelo. Consejo Superior de Investigaciones Científicas; EspañaFil: Alonso, José Antonio. Instituto de Ciencia de Materiales de Madrid; Españ