Primer informe de virus infectando cártamo en Argentina

PosterEl cártamo (Carthamus tinctorius L.) es una oleaginosa anual de ciclo inverno-primaveral, adaptada a condiciones de aridez y reconocida por la calidad de su aceite. En Argentina el cártamo se cultiva principalmente en la región del noroeste, y en Buenos Aires y La Pampa en menor medida. Aunque se han informado varios virus infectando esta especie, en Argentina no existen reportes al respecto. En plantaciones experimentales de cártamo realizadas en Bahía Blanca, provincia de Buenos Aires, en el año 2019 se muestrearon plantas con mosaico, necrosis y deformación en distintos órganos, que en algunos casos terminó con la muerte de la planta (Fig. 1). El objetivo fue identificar al agente causal de los síntomas observados.Instituto de Patología VegetalFil: Cabrera Mederos, Dariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Cabrera Mederos, Dariel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Cerrotta, A. Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS). Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lindström, L.I. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Trucco, Veronica Milagros. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Trucco, Veronica Milagros. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Castellanos Collazo, Onias. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Giolitti, Fabian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Giolitti, Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); Argentin

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Thermal double donor annihilation and oxygen precipitation at around 650°C in Czochralski-grown Si: Local vibrational mode studies

We have used local vibrational mode (LVM) spectroscopy to monitor the formation of oxygen-related thermal double donors (TDDs) at 450°C and their annihilation at 650°C in carbon-lean Czochralski-grown (Cz-) Si crystals. A few samples were treated at 650°C under high hydrostatic pressure. It is found that the annihilation of TDDs at 650°C results not only in a partial recovery of the interstitial oxygen, but also in the appearance of a number of new O-related LVM bands in the range 990-1110 cm-1. The positions of these lines and their shapes are identical to those observed for Cz-Si irradiated with electrons or neutrons and annealed at 600-700°C. Since the lines appear upon annealing out of V O3 and V O4 defects in irradiated samples, they are suggested to arise from V Om (m>4) complexes. In both kinds of samples, pre-annealed and pre-irradiated, the new LVM bands disappear upon prolonged annealing at 650°C while enhanced oxygen precipitation occurs. The V Om defects are suggested to serve as nuclei for oxygen precipitates developing at around 650°C. High hydrostatic pressure is found to enhance further (up to 4-5 times) the oxygen precipitation process at 650°C in the samples pre-annealed at 450°C. © 2005 IOP Publishing Ltd

Divacancy-oxygen and trivacancy-oxygen complexes in silicon: Local vibrational mode studies

Fourier transform infrared absorption spectroscopy was used to study the evolution of multivacancy-oxygen-related defects in the temperature range 200-300 °C in Czochralski-grown Si samples irradiated with MeV electrons or neutrons. A clear correlation between disappearance of the divacancy (V 2) related absorption band at 2767 cm-1 and appearance of two absorption bands positioned at 833.4 and 842.4 cm-1 at 20 K (at 825.7 and 839.1 cm-1 at room temperature) has been found. Both these two emerging bands have previously been assigned to a divacancy-oxygen defect formed via interaction of mobile V2 with interstitial oxygen (O i) atoms. The present study shows, however, that the two bands arise from different defects since the ratio of their intensities depends on the type of irradiation. The 842.4 cm-1 band is much more pronounced in neutron irradiated samples and we argue that it is related to a trivacancy-oxygen defect (V3O) formed via interaction of mobile V3 with Oi atoms or/and interaction of mobile V 2 with VO defects. © (2010) Trans Tech Publications

Trivacancy-oxygen complex in silicon: Local vibrational mode characterization

FTIR study of the evolution of multivacancy-oxygen-related defects in the temperature range 100-350 °C in Czochralski-grown Si samples irradiated with different particles (10 MeV electrons and 5 MeV neutrons) has been carried out. Appearance of two absorption bands positioned at 833.4 and 842.4 cm-1 has been found upon annealing of the divacancy related absorption band at 2767 cm-1. The 833.4 cm-1 band is assigned to a divacancy-oxygen defect. The 842.4 cm-1 band is much more pronounced in neutron irradiated samples and we argue that it is related to a trivacancy-oxygen defect formed via interaction of mobile V3 with Oi atoms. © 2009 Elsevier B.V. All rights reserved

VOn (n>3) defects in irradiated and heat-treated silicon

Local vibrational mode (LVM) spectroscopy has been used to study the evolution of vacancy-oxygen-related defects (VOn) in the temperature range 300-700°C in carbon-lean Cz-Si samples irradiated with MeV electrons or neutrons. New experimental data confirming an attribution of the absorption bands at 910, 976 and 1105 cm-1 to the VO3 complex are obtained. In particular, a correlated generation Of VO3 and the oxygen trimer is observed upon irradiation of CzSi crystals in the temperature range 300-400°C. Strong evidence for the assignment of the bands at 991 and 1014 cm-1 to a VO4 defect is presented. The lines are found to develop very efficiently in the VO2 containing materials enriched with the oxygen dimer. In such materials the formation of VO 4 is enhanced due to occurrence of the reaction O 2i+VO2 ⇒ VO4. Annealing of the VO 3 and VO4 defects at T > 550C °C is found to result in the appearance of new defects giving rise to a number of O-related LVM bands in the range 990-1110 cm-1. These bands are suggested to arise from VO5 and/or VO6 defects. Similar bands also appear upon the annihilation of oxygen-related thermal double donors at 650°C in Cz-Si crystals pre-annealed at 450°C

Stable hydrogen pair trapped at carbon impurities in silicon

Local mode spectroscopy and ab initio modeling are used to investigate two trigonal defects found in carbon rich Si into which H had been in-diffused. Isotopic shifts with D and 13C are reported along with the effect of uniaxial stress. Ab-initio modeling studies suggest that the two defects are two forms of the CH2* complex where one of the two hydrogen atoms lies at an anti-bonding site attached to C or Si respectively. The two structures are nearly degenerate and possesess vibrational modes in good agreement with those observed experimentally. The defects are energetically favorable in comparison with separated Cs and H2 in Si and may represent aggregation sites for hydrogen.Validerad; 2003; 20070223 (kani)</p