MicroRNAs as regulators in plant metal toxicity response

Metal toxicity is a major stress affecting crop production. This includes metals that are essential for plants (copper, iron, zinc, manganese), and non-essential metals (cadmium, aluminum, cobalt, mercury). A primary common effect of high concentrations of metal such as aluminum, copper, cadmium, or mercury is root growth inhibition. Metal toxicity triggers the accumulation of reactive oxygen species leading to damage of lipids, proteins, and DNA. The plants response to metal toxicity involves several biological processes that require fine and precise regulation at transcriptional and post-transcriptional levels. MicroRNAs (miRNAs) are 21 nucleotide non-coding RNAs that regulate gene expression at the post-transcriptional level. A miRNA, incorporated into a RNA-induced silencing complex, promotes cleavage of its target mRNA that is recognized by an almost perfect base complementarity. In plants, miRNA regulation is involved in development and also in biotic and abiotic stress responses. We review novel advances in identifying miRNAs related to metal toxicity responses and their potential role according to their targets. Most of the targets for plant metal-responsive miRNAs are transcription factors. Information about metal-responsive miRNAs in different plants points to important regulatory roles of miR319, miR390, miR393, and miR398. The target of miR319 is the TCP transcription factor, implicated in growth control. miR390 exerts its action through the biogenesis of trans-acting small interference RNAs that, in turn, regulate auxin responsive factors. miR393 targets the auxin receptors TIR1/AFBs and a bHLH transcription factor. Increasing evidence points to the crucial role of miR398 and its targets Cu/Zn superoxide dismutases in the control of the oxidative stress generated after high copper or iron exposure

Enkapsulacija askorbinske kiseline u hidrofobnom silikagelu

Self-assembled hybrid organo-silica sol-gel materials are rapidly expanding for newand novel applications. The microporous solid silica matrix was used as a carrier for the controlled release of ascorbic acid (AA), selected as cargo molecule. One-step synthesis procedure was optimized for the preparation of silica–molecule composites by using tetraethoxysilane and methyltrimethoxysilane as precursors. The hydrophobic silica xerogel matrices were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction. Specific surface area and porosity parameters were determined by Brunauer-Emmett-Teller (BET) technique and the matrix surface morphology by scanning electron microscopy (SEM). The observed release pattern could be interesting for the development of AA-fortified food and for use in food packaging.Hibridni, organsko-silikatni sol-gel materijal sve se više primjenjuje u prehrambenoj industriji. Stoga je kao nosač za kontrolirano otpuštanje askorbinske kiseline upotrijebljen mikroporozni čvrsti silikatni matriks. Optimirana je jednostupanjska sinteza kojom su dobiveni silikatni kompoziti uz pomoć prekurzora: tetraetoksisilana i metiltrimetoksisilana. Matriksi su hidrofobnog silikagela okarakterizirani Fourier transformiranom infracrvenom spektroskopijom (FTIR) i difrakcijom X-zraka. Specifična površina i poroznost matriksa ispitane su Brunaer-Emmett-Teller (BET) metodom, dok su morfološka svojstva površine matriksa određena skenirajućim elektronskim mikroskopom (SEM). Utvrđeno je da se askorbinska kiselina ovako može upotrijebiti za proizvodnju hrane s dodanom vrijednošću, te za pakiranje prehrambenih proizvoda

Enkapsulacija askorbinske kiseline u hidrofobnom silikagelu

Self-assembled hybrid organo-silica sol-gel materials are rapidly expanding for newand novel applications. The microporous solid silica matrix was used as a carrier for the controlled release of ascorbic acid (AA), selected as cargo molecule. One-step synthesis procedure was optimized for the preparation of silica–molecule composites by using tetraethoxysilane and methyltrimethoxysilane as precursors. The hydrophobic silica xerogel matrices were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction. Specific surface area and porosity parameters were determined by Brunauer-Emmett-Teller (BET) technique and the matrix surface morphology by scanning electron microscopy (SEM). The observed release pattern could be interesting for the development of AA-fortified food and for use in food packaging.Hibridni, organsko-silikatni sol-gel materijal sve se više primjenjuje u prehrambenoj industriji. Stoga je kao nosač za kontrolirano otpuštanje askorbinske kiseline upotrijebljen mikroporozni čvrsti silikatni matriks. Optimirana je jednostupanjska sinteza kojom su dobiveni silikatni kompoziti uz pomoć prekurzora: tetraetoksisilana i metiltrimetoksisilana. Matriksi su hidrofobnog silikagela okarakterizirani Fourier transformiranom infracrvenom spektroskopijom (FTIR) i difrakcijom X-zraka. Specifična površina i poroznost matriksa ispitane su Brunaer-Emmett-Teller (BET) metodom, dok su morfološka svojstva površine matriksa određena skenirajućim elektronskim mikroskopom (SEM). Utvrđeno je da se askorbinska kiselina ovako može upotrijebiti za proizvodnju hrane s dodanom vrijednošću, te za pakiranje prehrambenih proizvoda

Colector solar plano de policarbonato alveolar

Se construyó y ensayó un colector solar plano para calentamiento de agua constituido por una placa de policarbonato alveolar con una de sus caras pintada de negro. Las celdas de la placa hacen de conductos para la circulación del agua. Se obtuvieron experimentalmente las curvas de eficiencia para dos configuraciones de la placa: con la superficie negra hacia arriba, recibiendo la radiación y con la superficie negra hacia abajo, incidiendo la radiación sobre la superficie transparente del policarbonato.It was built and tested a flat plate solar collector for water heating constituted by a policarbonate structured sheet with one of their faces painted of black. The cells of the plate constitute the conduits for where the water circulates. They were experimentally obtained the curves of efficiency for two configurations of the plate: with the black surface up, receiving the radiation and with the black surface down, impacting the radiation on the transparent surface of the plate.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Colector solar plano de policarbonato alveolar

Se construyó y ensayó un colector solar plano para calentamiento de agua constituido por una placa de policarbonato alveolar con una de sus caras pintada de negro. Las celdas de la placa hacen de conductos para la circulación del agua. Se obtuvieron experimentalmente las curvas de eficiencia para dos configuraciones de la placa: con la superficie negra hacia arriba, recibiendo la radiación y con la superficie negra hacia abajo, incidiendo la radiación sobre la superficie transparente del policarbonato.It was built and tested a flat plate solar collector for water heating constituted by a policarbonate structured sheet with one of their faces painted of black. The cells of the plate constitute the conduits for where the water circulates. They were experimentally obtained the curves of efficiency for two configurations of the plate: with the black surface up, receiving the radiation and with the black surface down, impacting the radiation on the transparent surface of the plate.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Colector solar plano de policarbonato alveolar

Se construyó y ensayó un colector solar plano para calentamiento de agua constituido por una placa de policarbonato alveolar con una de sus caras pintada de negro. Las celdas de la placa hacen de conductos para la circulación del agua. Se obtuvieron experimentalmente las curvas de eficiencia para dos configuraciones de la placa: con la superficie negra hacia arriba, recibiendo la radiación y con la superficie negra hacia abajo, incidiendo la radiación sobre la superficie transparente del policarbonato.It was built and tested a flat plate solar collector for water heating constituted by a policarbonate structured sheet with one of their faces painted of black. The cells of the plate constitute the conduits for where the water circulates. They were experimentally obtained the curves of efficiency for two configurations of the plate: with the black surface up, receiving the radiation and with the black surface down, impacting the radiation on the transparent surface of the plate.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Hydrodynamic identification of NAUTILUS FOWT platform from small scale tests

A small-scale tank test campaign of the NAUTILUS offshore wind floating semisub-mersible platform was held at the Ifremer Deep Water Basin within the framework of the MaRINET 2 project. The support structure consists in four stabilized columns on a square pontoon supporting a generic 8-MW wind turbine. The tests were carried out at 1:36 Froude scale in parked conditions, and the mooring system was modelled as a set of aerial mooring springs providing a nonlinear stiffness. The hydrodynamic characterization of the floater from experimental data was tackled by using traditional techniques in naval architecture), as well as approaches derived from operational modal analysis in the frequency domain, such as the Sub Space Identification—Covariance (SSI-COV) method. The validity of this approach and its potential application to the identification of such kind of structures is discussed against the results of a more traditional technique based on the fitting of decay tests

Aperture effects on the oxygen abundance determinations from CALIFA data

This paper aims at providing aperture corrections for emission lines in a sample of spiral galaxies from the Calar Alto Legacy Integral Field Area Survey (CALIFA) database. In particular, we explore the behavior of the log([OIII]5007/Hbeta)/([NII]6583/Halpha) (O3N2) and log[NII]6583/Halpha (N2) flux ratios since they are closely connected to different empirical calibrations of the oxygen abundances in star forming galaxies. We compute median growth curves of Halpha, Halpha/Hbeta, O3N2 and N2 up to 2.5R_50 and 1.5 disk R_eff. The growth curves simulate the effect of observing galaxies through apertures of varying radii. The median growth curve of the Halpha/Hbeta ratio monotonically decreases from the center towards larger radii, showing for small apertures a maximum value of ~10% larger than the integrated one. The median growth curve of N2 shows a similar behavior, decreasing from the center towards larger radii. No strong dependence is seen with the inclination, morphological type and stellar mass for these growth curves. Finally, the median growth curve of O3N2 increases monotonically with radius. However, at small radii it shows systematically higher values for galaxies of earlier morphological types and for high stellar mass galaxies. Applying our aperture corrections to a sample of galaxies from the SDSS survey at 0.02<=z<=0.3 shows that the average difference between fiber-based and aperture corrected oxygen abundances, for different galaxy stellar mass and redshift ranges, reaches typically to ~11%, depending on the abundance calibration used. This average difference is found to be systematically biased, though still within the typical uncertainties of oxygen abundances derived from empirical calibrations. Caution must be exercised when using observations of galaxies for small radii (e.g. below 0.5R_eff) given the high dispersion shown around the median growth curves.Comment: Accepted for publication in Ap

Surface shape resonances in lamellar metallic gratings

The specular reflectivity of lamellar gratings of gold with grooves 0.5 microns wide separated by a distance of 3.5 microns was measured on the 2000 cm$^{-1}$ - 7000 cm$^{-1}$ spectral range for p-polarized light. For the first time, experimental evidence of the excitation of electromagnetic surface shape resonances for optical frequencies is given. In these resonances the electric field is highly localized inside the grooves and is almost zero in all other regions. For grooves of depth equal to 0.6 microns, we have analyzed one of these modes whose wavelength (3.3 microns) is much greater than the lateral dimension of the grooves.Comment: 4 pages (LaTex), 5 postscript figures, to be published in Physical Review Letter