BETs: Propellant less de orbiting of space debris by bare electrodynamic tethers

As a fundamental contribution to limiting the increase of debris in the Space environment, a three-year project started on 1 November 2010 financed by the European Commission under the FP-7 Space Programme. It aims at developing a universal system to be carried on board future satellites launched into low Earth orbit (LEO), to allow de-orbiting at end of life. The operational system involves a conductive tape-tether left bare of insulation to establish anodic contact with the ambient plasma as a giant Langmuir probe. The project will size the three disparate dimensions of a tape for a selected de-orbit mission and determine scaling laws to allow system design for a general mission. It will implement control laws to restrain tether dynamics in/off the orbital plane; and will carry out plasma chamber measurements and numerical simulations of tether-plasma interaction. The project also involves the design and manufacturing of subsystems: electron-ejecting plasma contactors, an electric control and power module, interface elements, tether and deployment mechanisms, tether tape/end-mass as well as current collection plus free-fall, and hypervelocity impact tests

Propellantless de orbiting of space debris by bare electrodynamic tethers

A 3-year Project started on November 1 2010, financed by the European Commision within the FP-7 Space Program, and aimed at developing an efficient de-orbit system that could be carried on board by future spacecraft launched into LEO, will be presented. The operational system will deploy a thin uninsulated tape-tether to collect electrons as a giant Langmuir probe, using no propellant/no power supply, and generating power on board. This project will involve free-fall tests, and laboratory hypervelocity-impact and tether-current tests, and design/Manufacturing of subsystems: interface elements, electric control and driving module, electron-ejecting plasma contactor, tether-deployment mechanism/end-mass, and tape samples. Preliminary results to be presented involve: i) devising criteria for sizing the three disparate tape dimensions, affecting mass, resistance, current-collection, magnetic self-field, and survivability against debris itself; ii) assessing the dynamical relevance of tether parameters in implementing control laws to limit oscillations in /off the orbital plane, where passive stability may be marginal; iii) deriving a law for bare-tape current from numerical simulations and chamber tests, taking into account ambient magnetic field, ion ram motion, and adiabatic electron trapping; iv) determining requirements on a year-dormant hollow cathode under long times/broad emission-range operation, and trading-off against use of electron thermal emission; v) determining requirements on magnetic components and power semiconductors for a control module that faces high voltage/power operation under mass/volume limitations; vi) assessing strategies to passively deploy a wide conductive tape that needs no retrieval, while avoiding jamming and ending at minimum libration; vii) evaluating the tape structure as regards conductive and dielectric materials, both lengthwise and in its cross-section, in particular to prevent arcing in triple-point junctions

An universal system to de-orbit satellites at end of life

A 3-year Project financed by the European Commission is aimed at developing a universal system to de-orbit satellites at their end of life, as a fundamental contribution to limit the increase of debris in the Space environment. The operational system involves a conductive tapetether left bare to establish anodic contact with the ambient plasma as a giant Langmuir probe. The Project will size the three disparate dimensions of a tape for a selected de-orbit mission and determine scaling laws to allow system design for a general mission. Starting at the second year, mission selection is carried out while developing numerical codes to implement control laws on tether dynamics in/off the orbital plane; performing numerical simulations and plasma chamber measurements on tether-plasma interaction; and completing design of subsystems: electronejecting plasma contactor, power module, interface elements, deployment mechanism, and tether-tape/end-mass. This will be followed by subsystems manufacturing and by currentcollection, free-fall, and hypervelocity impact tests

Plant mitochondria under pathogen attack: A sigh of relief or a last breath?

Plants constitute excellent sources for pathogen nutrition and survival. To fight against pathogen attack, higher plants have developed a sophisticated immune system responsible for pathogen recognition and activation of downstream defense responses. After pathogen perception, mitochondria play an important role in the defense strategy of the plant cell, integrating and amplifying diverse signals such as salicylic acid, nitric oxide, reactive oxygen species (ROS) or pathogen elicitors. Signals perceived by mitochondria usually impact on their normal function, destabilizing the organelle, generating changes in respiration, membrane potential and ROS production. At this stage, mitochondria produce several signals influencing the redox state of the cell and promoting changes in the expression of nuclear genes by mitochondrial retrograde regulation. At more advanced stages, they promote programmed cell death in order to avoid pathogen propagation to the whole plant. Recent evidence indicates that plants and pathogens have evolved mechanisms to modulate the immune response by acting on mitochondrial functions. In this review, we summarize knowledge about the involvement of mitochondria in different aspects of the response of plants to pathogen attack.Fil: Colombatti, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Ciencias Biológicas. Cátedra de Biología Celular y Molecular; ArgentinaFil: Gonzalez, Daniel Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Ciencias Biológicas. Cátedra de Biología Celular y Molecular; ArgentinaFil: Welchen, Elina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Ciencias Biológicas. Cátedra de Biología Celular y Molecular; Argentin

Obtenção de leite integral sem colesterol com a utilização de β-cyclodextrina

El colesterol dietario, asociado a dicha grasa, determina en un 20% la concentración del colesterol plasmático, el cual produce enfermedades coronarias y cerebrovasculares. Este porcentaje suele promover hipercolesterolemia, siendo grasa láctea muy rica en vitamina D, ácido linoleico conjugado y promotora de características texturales (cremosidad, palatabilidad) y de flavor irreemplazables, considerándose actualmente sus ácidos grasos saturados, neutros en cuanto a la generación de enfermedades coronarias y cerebrovasculares, conviniendo no extraer dicha grasa láctea. El objetivo fue optimizar la extracción de colesterol, sin extraer la grasa láctea, y evaluar la aceptabilidad de las leches obtenidas. Se investigó la extracción del colesterol en leche, con β-ciclodextrina, utilizándose un diseño experimental (2 variables: Porcentaje β-ciclodextrina y presión de homogeneización, en 3 niveles: 0,9-1,5% y 110-160 atm.). El máximo porcentaje de extracción de colesterol fue 92%. En todos los casos se obtuvo un porcentaje de extraccíon mayor al 80% lo que permite cumplir con la reglamentación vigente, respecto a que su concentración sea menor de 5 mg/100g, y permite obtener leche y productos lácteos "sin colesterol". De la evaluación sensorial se observó que el 80-85% de los evaluadores tuvo una buena y muy buena aceptación. Solo al 5-10% le disgustó el sabor dulce generado.O colesterol da dieta, que está relacionado com a gordura, determina 20% da concentração de colesterol no plasma, o que provoca  doenças cardíacas e cerebrovasculares. Essa percentagem promove a hipercolesterolemia. A gordura láctea é muito rica em vitamina A, ácido linoleico conjugado e promove características de textura (cremosidade, palatabilidade) e sabor insubstituível. Os ácidos graxos saturados da gordura láctea são considerados atualmente neutros quanto à geração de doença cardíaca e cerebrovascular, portanto, deve-se evitar a extração desses ácidos graxos da gordura láctea. O objetivo deste trabalho foi otimizar a extração de colesterol, sem extrair a gordura do leite e avaliar a aceitabilidade do leite obtido. Foi avaliado a extração do colesterol no leite, com β-ciclodextrina, utilizando-se um delineamento experimental com duas variáveis: porcentagem β-ciclodextrina e pressão de homogeneização, em 3 níveis: 0,9-1,5% e 110-160 atm. A porcentagem máxima de extração de colesterol foi de 92%. Em todos os casos, a porcentagem de extração foi superior a 80%, o que está em conformidade com a regulamentação existente, em relação a concentração do colesterol ser inferior a 5mg/100 g. Isso permite obter leite e produtos lácteos "sem colesterol". Na avaliação sensorial observou-se que 80-85% dos avaliadores aceitaram bem e muito bem o leite tratado com β-ciclodextrina . Apenas 5-10% não gostou do sabor doce gerado. 

OXR2 increases plant defense against a hemibiotrophic pathogen via the salicylic acid pathway

Arabidopsis thaliana OXIDATION RESISTANCE 2 (AtOXR2) is a mitochondrial proteinbelonging to the Oxidation Resistance (OXR) protein family, recently described in plants. Weanalyzed the impact of AtOXR2 in Arabidopsis defense mechanisms against thehemibiotrophic bacterial pathogen Pseudomonas syringae. oxr2 mutant plants are moresusceptible to infection by the pathogen and, conversely, plants over-expressing AtOXR2(oeOXR2 plants) show enhanced disease resistance. Resistance in these plants is accompaniedby higher expression of WRKY transcription factors, induction of genes involved in salicylicacid (SA) synthesis, accumulation of free SA, and overall activation of the SA-signalingpathway. Accordingly, defense phenotypes are dependent on SA-synthesis and SA-perceptionpathways, since they are lost in ics1/sid2 (isochorismate synthase 1/salicylic acid inductiondeficient 2) and npr1 (nonexpressor of pathogenesis-related genes 1) mutant backgrounds.Over-expression of AtOXR2 leads to faster and stronger oxidative burst in response to thebacterial flagellin peptide flg22. Moreover, AtOXR2 affects the nuclear localization of thetranscriptional coactivator NPR1, a master regulator of SA signaling. oeOXR2 plants haveincreased levels of total glutathione and a more oxidized cytosolic redox cellular environmentunder normal growth conditions. Therefore, AtOXR2 contributes to establishing plantprotection against infection by P. syringae acting on the activity of the SA pathway.Fil: Mencia, Regina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Céccoli, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias. Cátedra de Morfología Vegetal; ArgentinaFil: Fabro, Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Torti, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Colombatti, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Ludwig-Müller, Jutta. Technische Universität Dresden; AlemaniaFil: Alvarez, Maria Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Welchen, Elina. Technische Universität Dresden; Alemani