Wheat lines, suffering structural rearrangements between wheat-1BS and rye-1RS chromosomes, display differential patterns of magnesium accumulation

Poster no. 238Two near isogenic lines, designated as 1RS and 1RW, resulting from the recombination of the rye (Secale cereale) chromosome 1RS with chromosome 1BS of bread wheat (Triticum aestivum), differ in a relatively small region of that short chromosome arm. We have recently reported that chromosome rearrangements in this region imply modifications in the dosage of some genes (including OPRIII codifying an enzyme involved in jasmonic acid (JA) biosynthesis pathway). This dosage difference confer differential drought resistance in a way primarily associated to the capacity of roots for soil exploration. An emerging question is whether or not those rearrangements also differentially influence plant mineral nutrition. In the present study we analyzed the ionome of 1RS and 1RW, which unveiled the existence of relevant differences in the distribution of magnesium (Mg) between the shoot and the root of these lines. Following this observation, we explored the physiological and molecular determinants of differential magnesium accumulation observed.Instituto de Recursos BiológicosFil: Gualano, L.D. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Tecnológico Chascomús; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Moriconi, Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Tecnológico Chascomús; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Tranquilli, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Santa-María, Guillermo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Tecnológico Chascomús; Argentina. Universidad Nacional de San Martín; Argentin

Enhanced solar driven photocatalytic removal of antibiotics from aquaculture effluents by TiO2/carbon quantum dot composites

Aquaculture exploitation is associated with the consumption of antibiotics, such as sulfadiazine (SDZ), sulfamethoxazole (SMX) and trimethoprim (TMP), the latter two being also vastly used to treat bacterial infections in humans. Consequently, and given that aquaculture wastewater treatments are not actually designed for the removal of antibiotics, they are ubiquitous in aquaculture effluents, which sets the risk of bacterial resistance. To face the need for an efficient and sustainable treatment to remove these antibiotics from the referred effluents, carbon quantum dots (CQDs) were produced, incorporated into titanium dioxide (TiO2), and evaluated for solar driven photodegradation of SDZ, SMX and TMP. Eleven different materials were synthesized and tested for their photocatalytic activity in phosphate buffer solution (PBS) and synthetic sea salts (SSS), used as synthetic matrices to simulate fresh and brackish water, respectively. Upon selection of the most efficient photocatalyst for each antibiotic and matrix, kinetic results demonstrated that its use allowed for remarkable reductions of SDZ, SMX and TMP half-life times (t1/2) in both matrices (between 19 and 68 times). Therefore, the application of the here synthesized photocatalysts for the advanced treatment of aquaculture effluents is promising, allowing for a green solar driven removal of antibiotics.publishe

First-Principles Study on Peierls Instability in Infinite Single-Row Al Wires

We present the relation between the atomic and spin-electronic structures of infinite single-row atomic wires made of Al atoms during their elongation using first-principles molecular-dynamics simulations. Our study reveals that the Peierls transition indeed occurs in the wire with magnetic ordering: it ruptures to form a trimerized structure with antiferromagnetic ordering and changes from a conductor to an insulator just before forming a linear wire of equally-spaced atoms. The formation of the trimerized wire is discussed in terms of the behavior of the $\sigma$-symmetry bands of the Al wire.Comment: 10 pages, 4 figure

Quasilocal equilibrium condition for black ring

We use the conservation of the renormalized boundary stress-energy tensor to obtain the equilibrium condition for a general (thin or fat) black ring solution. We also investigate the role of the spatial stress in the thermodynamics of deformation within the quasilocal formalism of Brown and York and discuss the relation with other methods. In particular, we discuss the quantum statistical relation for the unbalanced black ring solution.Comment: v2: refs. added, matches the published versio

Density functional method for nonequilibrium electron transport

We describe an ab initio method for calculating the electronic structure, electronic transport, and forces acting on the atoms, for atomic scale systems connected to semi-infinite electrodes and with an applied voltage bias. Our method is based on the density functional theory (DFT) as implemented in the well tested Siesta approach (which uses non-local norm-conserving pseudopotentials to describe the effect of the core electrons, and linear combination of finite-range numerical atomic orbitals to describe the valence states). We fully deal with the atomistic structure of the whole system, treating both the contact and the electrodes on the same footing. The effect of the finite bias (including selfconsistency and the solution of the electrostatic problem) is taken into account using nonequilibrium Green's functions. We relate the nonequilibrium Green's function expressions to the more transparent scheme involving the scattering states. As an illustration, the method is applied to three systems where we are able to compare our results to earlier ab initio DFT calculations or experiments, and we point out differences between this method and existing schemes. The systems considered are: (1) single atom carbon wires connected to aluminum electrodes with extended or finite cross section, (2) single atom gold wires, and finally (3) large carbon nanotube systems with point defects.Comment: 18 pages, 23 figure