Variabilidad del método Folin-Denis en la determinación de equivalentes de ácido tánico en muestras de sorgo

The purpose of this work is to evaluate the influence of some factor that condition the variability of the Folin-Denis method to determine de equivalents of tannic acid in grain of sorghum. We studied the influence of the centrifugation previous to the spectrophotometric measurement. It was also studied the most convenient refluxed time for the extraction of tannic substances. The application of centrifugation to the aqueous extract after a night rest showed highly significant differences (p< 0,01) with respect to the sample without centrifugation. Considering both procedures, we got "r" 0,997 and the equation of regressi0n responds to y = 0,0627 + 1,033 x. The coefficient of variations fluctuates between 1,94 and 5,77 % for samples without centrifugation and between 0,71 and 3,85 % for samples with centrifugation. Therefore, in order to decrease the variability of the methods it is convenient to apply a ten-minute centrifugation at 5.000 rpm to the aqueous extract. It was determined that for the refluxe time there are no differences of extraction between 2 and 5 hours, though it tends to increase as time increases. For routine determinations a 3 hours refluxe extraction is enough but 5 hours are advisable for greater precision.El propósito del presente trabajo es evaluar la influencia de algunos factores que condicionan la variabilidad del método de Folin-Denis para determinar equivalentes de ácido tánico en grano de sorgo. Se estudió la influencia de la centrifugación previa a la medición espectrofotométrica y el tiempo de reflujo más conveniente para la extracción de sustancias tánicas. La aplicación de centrifugación al extracto acuoso, previo reposo de toda la noche, mostró diferencias altamente significativas (p<0,01) con respecto al testigo sin centrifugar. Entre ambos procedimientos se obtuvo "r" = 0,997 y la ecuación de regresión responde a y = 0,0627 + 1,033 x. Los coeficientes de variación oscilaron entre 1,94 y 5,77 % para muestras sin centrifugar y 0,71 a 3,85 % con centrifugación. Por 10 tanto para disminuir la variabilidad del método conviene aplicar una centrifugación de 10 minutos a 500,0 r.p.m. al extracto acuoso. Para el tiempo de reflujo se determinó que existen diferencias de extracción entre 2 y 5 horas, aunque tiende a aumentar a medida que se incrementa el tiempo. Para determinaciones de rutina es suficiente una extracción de tres horas de reflujo, aunque para mayor precisión se recomiendan 5 horas

Variaciones del contenido de sustancias astringentes en distintos híbridos de sorgo en diferentes estados de madurez

Variation data of tannic acid equivalents in kernels of 38 grain sorghum hybrids at three different stages: solft dough, hard dough and ripening time are presented here. By means cluster annalysis four groups are differentiated. 1) With low tannin values at three stages. II) With high values at soft dough with a decreasing trend. III) Idem II but with higher values IV) High values at soft doug, low at hard dough and highest values at ripening time

Theoretical approach based on Monte-Carlo simulations to predict the cell survival following BNCT

International audienceWe present here a very preliminary work on BNCT Dosimetry. The approach is as follows:A full Monte Carlo calculation is used to separate all dose components and determine the corresponding physical dose fractions with a realistic clinical model.These dose fractions are then used as mixed fields to predict cell-survivals and RBE values for a specific cell-line, thanks to the radiobiological model NanOxTM

Design of close and open channels experiments to study molten salt flows

International audienc

Influencia del contenido de almidón dañado sobre la calidad galletitera en harinas de triticale

El objetivo del presente trabajo fue medir el contenido de almidón dañado en harinas de triticale obtenidas bajo diferentes condiciones de molienda y determinar su influencia sobre la calidad galletitera. Para ello se acondicionaron granos con distintos contenidos de humedad (12, 14 y 16%) y se obtuvieron harinas sobre las que se determinó el porcentaje de almidón dañado, el índice de retención de agua alcalina (IRAA), la capacidad de retención de carbonato de sodio (SRCcarb)y el factor galletita (FG). Los resultados mostraron que el incremento en el porcentaje de almidón dañado produjo un aumento en el índice de retención de agua alcalina y en la capacidad de retención de carbonato de sodio, pero no se observó el correspondiente deterioro de la calidad galletitera. Esta falta de asociación indica que otros factores, tales como las proteínas, no inciden en los índices de retención pero sí sobre la calidad galletitera. Es necesario profundizar el estudio sobre el efecto individual del almidón dañado, las proteínas y sus asociaciones

Thérapies par Capture Neutronique basées sur accélérateurs Accelerator Based- Neutron Capture Therapies (AB-NCT)

National audienceLe principe de la thérapie par capture neutronique est d’introduire à l’intérieur de la cellule tumorale une molécule comportant un noyau atomique (10B ou 157Gd) présentant une très grande section efficace de capture pour les neutrons thermiques, lesquels vont provoquer soit la fragmentation d’un noyau de 11B (BNCT), soit l’émission de nombreux électrons de basse énergie (électron Auger ou de conversion), ce qui crée une très forte dose locale (GdNCT). Les molécules utilisées ont une faible toxicité intrinsèque.Le développement de la NCT est très limité en comparaison d’autres thérapies (chimiothérapie, radiothérapie, hadronthérapie). Ceci est dû à la grande difficulté d’accès à des faisceaux de neutrons épithermiques (E<= 10 keV) à visée médicale. Les sources de neutrons basées sur l’utilisation d’un accélérateur (AB=accelerator based) représentent la meilleure solution maintenant accessible pour ces essais.Notre projet consiste à :• Construire, exploiter et valider la source de production de neutrons basée sur une cible de béryllium tournante. Cette cible sera en mesure de produire un flux élevé de neutrons par la réaction nucléaire: 9Be(d (1.45 MeV),n)10B ou 9Be(p (3 MeV),n).• Concevoir et construire un modérateur de neutrons.• Mettre au point les systèmes de détection pour caractériser et surveiller les champs de neutrons et la production de rayons gamma avant et pendant l’irradiation NCT.• Valider expérimentalement l’ensemble chambre-cible-modérateur avec un faisceau de 5 mA de deutons à 1,45 MeV au GANIL ou de 10 mA de protons à Saclay (IPHI).• Se focaliser sur la compréhension et l’optimisation les effets destructeurs de l’AB-NCT sur les cellules tumorales avec des expériences cellulaires et oeuf• Faire une étude de la dose biologique en NCT par simulation Monte Carlo• caractériser le potentiel d’induction de réponses immunitaires anti-tumorales• faire une étude médicale pour identifier les indications favorables à un essai de Phase 1/2

Accelerator Based Neutron Capture Therapies in France

Exposé oralInternational audienceIn France, we have started in 2015, an interdisciplinary work on AB-NCT profiting of a synergy among different research institutes: Laboratoire de Physique Subatomique et de Cosmologie de Grenoble (LPSC), the Institut Laue-Langevin (ILL) and the Institut de Physique Nucléaire de Lyon (IPNL) coming from nuclear physics, with neutron and gamma detection expertise and their medical applications, the Grenoble University Hospital (CHU) and the Institut Albert Bonniot (IAB) coming from radiobiology, biological research, and clinical experience.The main purpose of this collaboration is to enable the production of epithermal neutron fields in a hospital environment by contributing to the development of compact (accelerator based) neutron sources. In parallel, we plan to improve the understanding of the biophysical determinants of the effectiveness of treatment performing radiobiology studies by cell irradiations at the ILL and simulation modelling (see R. Delorme et al. contribution). In addition, a particular effort will be performed to understand and optimize the deleterious effects of AB-NCT on tumor cells and to characterize the potential induction of subsequent anti-tumor immune responses.Since the beginning of the project, the major realizations have been:- a rotating Be target design able to cope with 30 kW (20 mA of deuteron beam at 1.5 MeV) and on the thermal tests with an electron beam using the COMICAC facility at LPSC,- the design of a Beam Shaping Assembly (BSA) adapted to this rotating target,- the development of a neutron directional detection system to characterize and control the neutron fields before and during the NCT irradiation.We will present the fast neutron directional detector (MIMAC-FastN) able to characterize the fluence and the angular distribution of the neutron fields produced. Using a thin foil of natB inside the active volume, we can calibrate the detector with the same reaction that will be produced at the tumor level. We will show results of measurements of fast neutrons performed recently. We will present the design and thermal simulations of the original rotating target, with in situ regeneration capability, and the BSA adapted to it.All these contributions will be placed in the context of a national project profiting of know-how on high current ion sources and RFQ availabilities

Recommendations for an MSFR demonstrator pre-conceptual design

The present deliverable introduces the need for several demonstration tools before reaching the final levels of a zero power demonstrator and subsequently a power demonstrator from which an industrial prototype may be defined. Safety consideration by safety authorities should be addressed all along the demonstration process, and this should take time, more than that needed previously for older concepts. This is essential for an innovative reactor concept that has a potentially high level of intrinsic safety. Two designs have been presented for the final step of the power demonstrator. For the MSFR-like demonstrator, a rather small reactor would both fit the needs for a demonstrator and be the base for modular reactors (300MWth) with less than 2 cubic meters of fuel salt. A simplified version of such a small reactor would be a burner only reaching fissile regeneration with an additional fertile blanket. It may be the simplest prototype to build and operate. An alternative spherical core shape design has been also introduced, taking into account the strongly-coupled behavior of the reactor neutronics and thermal fluid dynamics. It is characterized by an arrangement of the fuel circuit that would still ensure good neutron economy and breeding performance, limit hot spots at walls and reduce the overall temperature of structural materials, improve the effectiveness of natural circulation under pump blockage accidents, and keep the design as simple as possible. Preliminary analyses of the pre-conceptual spherical core shape design have demonstrated such potentialities, it could be further investigated. At this point, several design and fuel composition options are still open after the EVOL-MARS collaboration. This is an illustration of the high flexibility of this concept both in terms of size and fuel composition. Proceeding further in the definition of the most suitable common demonstrator for all the foreseeable application of this concept, with priority to simplicity and compliance to the safety authority requirements will be an important next step of future international collaborations