Resumen El vino tinto variedad Vitis vinifera L. cv Tannat en los últimos años ha tomado relevancia por su alta concentración de polifenoles, esto le podría significar un rol protector sobre el genoma disminuyendo la formación de lesiones oxidativas. Los efectos a nivel celular de las radiaciones ionizantes en blancos como el ADN, componentes de cascadas de transducción de señales, resultan en lesiones letales, mutagénicas y recombinogénicas y en retardos en el ciclo celular. Se utilizó como modelo eucariota poblaciones de Saccharomyces cerevisiae en fase exponencial expuestas a radiación gamma (200 Gy) en presencia, o ausencia, de vino Tannat (10 % v/v) o de ácido tánico (60 µg/mL). Se estimaron las probabilidades de sobrevida y frecuencia mutagénica en distintas condiciones. Las muestras celulares expuestas a radiación ionizante presentaron una fracción de sobrevida de 0.21 ± 0.02 mientras que en las muestras irradiadas en presencia de vino Tannat o de ácido tánico la fracción de sobrevida fue de 0.33 ± 0.03 y 0.30 ± 0.03 respectivamente. Se observó en las poblaciones irradiadas un aumento significativo de la probabilidad de mutagénesis. En el caso de los tratamientos combinados se observó que la frecuencia mutagénica fue significativamente menor (gamma Tannat: 33%, gamma ácido tánico: 45% ). Estos resultados preliminares podrían indicar radioprotección moderada por parte de los compuestos estudiados, efecto que podría explicarse por las interacciones redox del ácido tánico y polifenoles contenidos en el vino con los radicales libres formados por las radiaciones ionizantes, además de la activación de vías de reparación genómica.

Abstract The red wine variety Vitis vinifera L. cv Tannat in recent years has gained relevance due to its high concentration of polyphenols, this could mean a protective role on the genome, reducing the formation of oxidative lesions. The effects at the cellular level of ionizing radiation on targets such as DNA, components of signal transduction cascades, result in lethal, mutagenic and recombinogenic lesions and delays in the cell cycle. Exponential phase populations of Saccharomyces cerevisiae exposed to gamma radiation (200 Gy) in the presence or absence of Tannat wine (10% v / v) or tannic acid (60 µg / ml) were used as a eukaryotic model. The probabilities of survival and mutagenic frequency in different conditions were estimated. Cellular samples exposed to ionizing radiation presented a survival fraction of 0.21 ± 0.02, while in samples irradiated in the presence of Tannat wine or tannic acid, the survival fraction was 0.33 ± 0.03 and 0.30 ± 0.03 respectively. A significant increase in the probability of mutagenesis was observed in irradiated populations. In the case of the combined treatments, it was observed that the mutagenic frequency was significantly lower (Tannat gamma: 33%, Tannic acid gamma: 45%). These preliminary results could indicate moderate radioprotection by the compounds studied, an effect that could be explained by the redox interactions of tannic acid and polyphenols contained in wine with the free radicals formed by ionizing radiation, in addition to the activation of genomic repair pathways.

Resumo A variedade de vinho tinto Vitis vinifera L. cv Tannat nos últimos anos tem ganhado relevância devido à sua alta concentração de polifenóis, o que pode significar um papel protetor do genoma, reduzindo a formação de lesões oxidativas. Os efeitos no nível celular da radiação ionizante em alvos como o DNA, componentes de cascatas de transdução de sinal, resultam em lesões letais, mutagênicas e recombinogênicas e atrasos no ciclo celular. Populações de fase exponencial de Saccharomyces cerevisiae expostas à radiação gama (200 Gy) na presença ou ausência de vinho Tannat (10% v / v) ou ácido tânico (60 µg / ml) foram utilizadas como modelo eucariótico. Foram estimadas as probabilidades de sobrevivência e frequência mutagênica em diferentes condições. As amostras celulares expostas à radiação ionizante apresentaram uma fração de sobrevivência de 0,21 ± 0,02, enquanto nas amostras irradiadas na presença de vinho Tannat ou ácido tânico, a fração de sobrevivência foi de 0,33 ± 0,03 e 0,30 ± 0,03, respectivamente. Um aumento significativo na probabilidade de mutagênese foi observado nas populações irradiadas. No caso dos tratamentos combinados, observou-se que a frequência mutagênica foi significativamente menor (Tannat gama: 33%, ácido tânico gama: 45%). Esses resultados preliminares podem indicar radioproteção moderada pelos compostos estudados, efeito que pode ser explicado pelas interações redox do ácido tânico e polifenóis contidos no vinho com os radicais livres formados pela radiação ionizante, além da ativação de vias de reparo genômico.

DNA repair pathways, cell cycle checkpoints, and redox protection systems are essential factors for securing genomic stability. The aim of the present study was to analyze the effect of Ilex paraguariensis (Ip) infusion and one of its polyphenolic components rutin on cellular and molecular damage induced by ionizing radiation. Ip is a beverage drank by most inhabitants of Argentina, Paraguay, Southern Brazil, and Uruguay. The yeast Saccharomyces cerevisiae (SC7Klys 2-3) was used as the eukaryotic model. Exponentially growing cells were exposed to gamma rays (γ) in the presence or absence of Ip or rutin. The concentrations used simulated those found in the habitual infusion. Surviving fractions, mutation frequency, and DNA double-strand breaks (DSB) were determined after treatments. A significant increase in surviving fractions after gamma irradiation was observed following combined exposure to γ+R, or γ+Ip. Upon these concomitant treatments, mutation and DSB frequency decreased significantly. In the mutant strain deficient in MEC1, a significant increase in γ sensitivity and a low effect of rutin on γ-induced chromosomal fragmentation was observed. Results were interpreted in the framework of a model of interaction between radiation-induced free radicals, DNA repair pathways, and checkpoint controls, where the DNA damage that induced activation of MEC1 nodal point of the network could be modulated by Ip components including rutin. Furthermore, ionizing radiation-induced redox cascades can be interrupted by rutin potential and other protectors contained in Ip.

Abstract A model to describe the interaction between a spherical permanent magnet and a square superconductor in the mixed state was elaborated. The proposal is based on image dipole ideas as is the case of the Frozen dipole model that has been used in the literature. More precisely, a frozen dipole was put in the center of the superconducting sample; this dipole “was born" when the first critical field was reached in that position. This led to the attractive force magnet-superconductor in the penetrated-field state. In the description of the Meissner state, the demagnetizing field was not included in the calculation. Both vertical and horizontal forces are discussed.

The change in electrical resistance due to mechanical deformation of carbon nanotube (CNT)/polymer composites can be rationalized in terms of two main effects: i) changes in the composite electrical resistivity due to changes in the CNT network configuration, and ii) deformation of the CNTs themselves. The contribution of CNT dimensional changes (ii) to the piezoresistivity of CNT/polymer composites is investigated here. A model based on a representative volume element which describes the CNT geometrical contribution to the composite electromechanical response (piezoresistivity) in terms of the CNT and matrix deformations is proposed. Finite element analysis is performed to correlate the macroscale composite strain to the individual CNT strain. The CNT geometric contribution to the piezoresistivity of the composite is quantified for a range of matrix elastic modulus and different CNT orientations. Based on the model predictions and previous experimental results, it is estimated that the contribution of the CNT deformation to the composite piezoresistivity is only about 5%, indicating that the dominant effect in the piezoresistivity of CNT/polymer composites is the change in the CNT network configuration.

The magnetic field of a permanent magnet is calculated analytically for different geometries. The cases of a sphere, cone, cylinder, ring and rectangular prism are studied. The calculation on the axis of symmetry is presented in every case. For magnets with cylindrical symmetry, we propose an approach based on an expansion in Legendre polynomials to obtain the field at points off the axis. The case of a cylinder magnet was analyzed with this method by calculating the force between two magnets of this shape. Experimental results are presented too, showing a nice agreement with theory.

The maximum force between a permanent magnet and a superconductor in the Meissner state has been calculated. The calculation was performed assuming the superconductor to be a perfect diamagnet and neglecting the London penetration depth. The resulting force takes into account the geometric dimensions of both the magnet and the superconductor. This constitutes an important improvement for the description of the maximum force attainable in these systems. The method can be applied in cases with azimuthal symmetry.

Se calculó la máxima fuerza entre un imán permanente y un superconductor en el estado Meissner. El cálculo se realizó suponiendo que el superconductor es un diamagneto perfecto y despreciando la longitud de penetración de London. La fuerza resultante toma en cuenta las dimensiones geométricas tanto del imán como del superconductor. Esto constituye una mejora importante para la descripción de la máxima fuerza obtenible en estos sistemas. El método puede ser aplicado en casos con simetría azimutal.

In the course of a phytochemical study of L. mollis Cav. the previously reported compounds patuletin-7-O-glucoside 1, 12-hydroxy-13-en-xanthorrhizol 2, 11-en-13-hydroxy-xanthorrhizol 3, xanthorrhizol 4, 12,13-epoxy-xanthorrhizol 5, and 1-α-angeloyloxycarotol 6, were isolated. The EtOH extract of the aerial parts showed selective phytotoxic effects on S.halepense. Compounds 2 and 3 exhibited potent herbicidal activity on S. halepense. Additionally, at all assayed doses, compound 2 affected drastically the root growth.

Un estudio de la química y de la actividad fitotóxica de L.mollis Cav. permitió el aislamiento de seis compuestos conocidos patuletina-7-O-glucósido 1, 12-hidroxi-13-en-xanthorrhizol 2, 11-en-13-hidroxi-xanthorrhizol 3, xanthorrhizol 4, 12,13-epoxi-xanthorrhizol 5 y 1-α-angeloiloxicarotol 6. El extracto etanólico de las partes aéreas de L. mollis mostró actividad fitotóxica selectiva en S. halepense. Los compuestos 2 y 3 exhibieron potente actividad herbicida frente a S. halepense. El compuesto 2 afectó drásticamente el crecimiento radicular de esta especie a todas las dosis ensayadas.

7,3'-dimethylquercetin 1, 7,3,3'-trimethylquercetin 2, 7,3,4'-trimethylquercetin 3 and quercetin 4 were isolated from aerial parts of Gutierrezia repens (Asteraceae). The structures of 1, 2 and 3 were determined mainly on the basis of 2D NMR data. Their ¹H NMR spectra in CDCl3 and Me2CO-d6 are compared and discussed. The 13C NMR spectra of these compounds are given here for the first time.

7,3'-dimetilquercetina 1, 7,3,3'-trimetilquercetina 2, 7,3,4'-trimetilquercetina 3 y quercetina 4 fueron aislados de las partes aéreas de Gutierrezia repens (Asteraceae). Las estructuras de 1, 2 y 3 fueron determinadas principalmente por espectroscopía 2D RMN. Sus espectros de RMN ¹H en CDCl3 y Me2CO-d6 son comparados y discutidos. En este trabajo informamos por primera vez, los espectros de RMN 13C de los flavonoides metilados.

La fasciolosis humana es una entidad poco frecuente reportada previamente 8 veces en Venezuela, de personas provenientes del centro y los estados occidentales. Se presenta el caso de un paciente masculino de 25 años, natural y procedente del Estado Bolívar, donde practica equitación y supervisa tareas de corral del ganado equino y bovino. La enfermedad actual se inicia con diarreas desde los 14 años, acompañada de persistente eosinofilia. ELISA e "Immunoblot", resultaron francamente positivos al antígeno de excreción- secreción de Fasciola hepática. Ante persistente dolor epigástrico, se practicó eco-endoscopia, resultando en la visualización de dilatación quística del ducto pancreático con una estructura interna probablemente correspondiente a un parásito. El examen parasitológico del contenido duodenal y heces reportó huevos de Fasciola hepática en este último material. Se administró tratamiento con Bithionol luego de lo cual disminuyó la eosinofilia y hubo franca mejoría clínica. Es el primer caso de fasciolosis humana proveniente del sureste del país, donde la fasciolosis bovina o humana no había sido descrita y en el cual además, ocurrió una localización ectópica pancreática de difícil diagnóstico clínico.

Human fasciolosis in Venezuela is an infrequent disease, reported only 8 times previously in persons coming from the center and the western states of the country. The case of a 25 years old masculine patient from Bolivar State, where he practices equitation and supervises tasks of corral of equine and bovine cattle is reported. The disease began with diarrhea at 14 years old, accompanied by persistent eosinofilia. ELISA and "Immunoblot" were strongly positive to excretion-secretion Fasciola hepatica antigen. Given the presence of persistent epigastric pain, echo-endoscopy was practiced, resulting in the visualization of cyst expansion of the pancreatic duct with an internal structure probably corresponding to a parasite. The parasitologic examination of the duodenal content and feces reported Fasciola hepatica eggs this last material. After treatment with Bithionol, eosinofilia diminished and there was frank clinical improvement. It is the first case of human fasciolosis of the southeastern part of the country, where bovine or human fasciolosis had not been described in which additionally, an ectopic pancreatic location of difficult clinical diagnosis occurred.