Impregnación del hormigón por resinas acrílicas

Not availableEl Jefe de la Sección de aplicaciones en el Centro de Estudios e Investigaciones del Hormigón CERIB, francés, el Ing. F. Dutruel ha publicado en la revista "Bétons Industriéis", (número 43 de 1973) la primera parte de un extenso e interesante estudio sobre las técnicas más convenientes para conseguir una impregnación acrílica del hormigón capaz de proporcionar la defensa más eficaz y el incremento de resistencias posible. El interés de esta cuestión así como la magnífica exposición del Ing. Dutruel justifica la publicación de un amplio resumen que mueva a los interesados en estos trabajos a leer el original, que pueden solicitar del Servicio de información de nuestro Instituto o consultarlo en la biblioteca del mismo

Producción ovina en la mesopotamia argentina : acciones y políticas desarrolladas para el sector

Dutruel, Florencia Josefina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal. Cátedra de Ovinotecnia. Buenos Aires, Argentina.De Caro, Adriana E. J. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal. Cátedra de Ovinotecnia. Buenos Aires, Argentina.45-53La producción ovina en la Argentina experimentó un declive en las últimas décadas debido principalmente a factores del mercado internacional y a la falta de políticas públicas de apoyo, llevando a la disminución en las cabezas en todo el país. No obstante, a partir del 2002 se evidencia un leve crecimiento en algunas regiones como la mesopotámica. En este trabajo, se analiza el sector ovino en Entre Ríos y Corrientes con la mirada en las políticas públicas y su impacto, caracterizando la actividad, su evolución y los principales acontecimientos (2003-2017). Las políticas públicas en esas provincias están dirigidas hacia los pequeños y medianos productores, cuyas majadas representan una actividad secundaria o complementaria; y se orientan a corregir falencias en la cadena de producción como: información poco sistematizada e incompleta, faena informal, falta de volumen de producción, estacionalidad marcada y productores con poco conocimiento sobre tecnologías de manejo adecuadas. La Ley Ovina es la de mayor impacto por su difusión y elección por parte de los productores, manteniéndose vigente en el tiempo. En menor grado, programas como PROLANA y Cambio Rural, han colaborado con su desempeño, al igual que los grupos de trabajo y la formación de cooperativas. En ambas provincias se debe trabajar para fortalecer la actividad con la participación del sector público y de los productores; y aun cuando la producción ovina se presenta como secundaria, las políticas y acciones orientadas específicamente al sector resultan herramientas que orientan al productor ovino hacia una actividad rentable

Expérimentation de systèmes viticoles à faible usage d’intrants phytosanitaires en Val de Loire.

Ce numéro est constitué d’articles de synthèse des projets DEPHY EXPE publiés à l’occasion du colloque national DEPHY, qui s’est déroulé les 13 et 14 novembre 2018 à la Cité des Sciences et de l'Industrie (Paris). Nous vous invitons à découvrir le bilan et les enseignements des 21 projets conduits sur la période 2012-2017.The EcoViti Val de Loire project evaluated various viticulture systems during 6 years. One system wasbased on a combination of already assessed practices (at the time of design), a second one on theimpact of the pruning system on diseases susceptibility, and the last on the association of grapevineand roses. These systems led to significant TFI reductions, with sometimes some drawbacks in terms ofyield. They also allowed to show the importance of the transition period in system experimentations, andthe interest to lead these experimentations from the plantation for perennial crops. The time for thesystem to get back in balance is not to be underestimated, even a plant as plastic as grapevine takesseveral years ti adapt to a change in pruning or soil management.Le projet EcoViti Val de Loire a évalué trois systèmes de culture viticoles pendant 6 ans. Le premiersystème était basé sur la combinaison de pratiques déjà éprouvées au moment du lancement du projet,un second sur l’impact du mode de taille de la vigne sur la sensibilité aux maladies, et le dernier surl’association de vigne et rosiers. Ces divers systèmes ont permis des réductions significatives d’IFT,avec parfois des revers, en termes de rendement notamment. Ils ont également mis en évidence lanécessité de prendre en compte la phase de transition dans les essais systèmes, et l’intérêt de menerles essais systèmes en culture pérenne dès la plantation. En effet, le temps de rééquilibrage d’uneplante pérenne n’est pas à sous-estimer, et même une plante aussi plastique que la vigne met plusieursannées pour s’adapter à une modification de taille ou de mode d’entretien du sol

Balancing Specificity and Promiscuity in Enzyme Evolution: Multidimensional Activity Transitions in the Alkaline Phosphatase Superfamily

Highly proficient, promiscuous enzymes can be springboards for functional evolution, able to avoid loss of function during adaptation by their capacity to promote multiple reactions. We employ systematic comparative study of structure, sequence and substrate specificity to track the evolution of specificity and reactivity between promiscuous members of clades of the alkaline phosphatase (AP) superfamily. Construction of a phylogenetic tree of protein sequences maps out the likely transition zone between arylsulfatases (ASs) and phosphonate monoester hydrolases (PMHs). Kinetic analysis shows that all enzymes characterized have four chemically distinct phospho- and sulfoesterase activities, with rate accelerations ranging from 1011-1017-fold for their primary and 109-1012-fold for their promiscuous reactions, suggesting that catalytic promiscuity is widespread in the AP-superfamily. This functional characterization and crystallography reveal a novel class of ASs that is so similar in sequence to known PMHs that it had not been recognized as having diverged in function. Based on analysis of snapshots of catalytic promiscuity ‘in transition’ we develop possible models that would allow functional evolution and determine scenarios for trade-off between multiple activities. For the new ASs we observe largely invariant substrate specificity that would facilitate the transition from ASs to PMHs via trade-off-free molecular exaptation, i.e. evolution without initial loss of primary activity and specificity toward the original substrate. This ability to bypass low activity generalists provides a molecular solution to avoid adaptive conflict.BBSR

TRANSVAC workshop on standardisation and harmonisation of analytical platforms for HIV, TB and malaria vaccines: 'how can big data help?'.

High-throughput analyses of RNA and protein expression are increasingly used for better understanding of vaccine-induced immunity and protection against infectious disease. With an increasing number of vaccine candidates in clinical development, it is timely to consider standardisation and harmonisation of sample collection, storage and analysis to ensure results of highest quality from these precious samples. These challenges were discussed by a group of international experts during a workshop organised by TRANSVAC, a European Commission-funded Research Infrastructure project. The main conclusions were: Platforms are rarely standardised for use in preclinical and clinical studies. Coordinated efforts should continue to harmonise the experimental set up of these studies, as well as the establishment of internal standards and controls. This will ensure comparability, efficiency and feasibility of the global analyses performed on preclinical and clinical data sets

Del currículo monocultural a la Didáctica de las Emergencias

El escrito entre sus manos intenta desarrollar un itinerario intelectual de doble entrada sobrela enseñanza en la Facultad de Trabajo Social de la Universidad Nacional de Entre Ríos: enprimera instancia, es una invitación a establecer una reflexión téorico-experiencial en torno ala producción de carácter epistemológico que Boaventura de Sousa Santos ha construido en losúltimos treinta años; en segunda instancia, es un ejercicio de argumentación a los fines de imaginaresa educación que aún no sabemos cómo nombrar: una educación donde los procesos deenseñanza sean entendidos como prácticas sociales de investigación/acción en vistas a moderaruna ecología de saberes. A medio camino, ambas se enlazan en el relato de una experiencia, elvoluntariado universitario «Produciendo Encuentros»

Early post-contrast T1 mapping yields maximal discriminatory capacity for detection of cardiac amyloid - influence of temporal T1 differences on MOLLI imaging

Background: Myocardial T1 mapping is increasingly used to diagnose and quantify disease burden in patients with known or suspected cardiac amyloid. Optimal timing for diagnostic application of T1 mapping is not established. Methods: Myocardial T1 mapping was performed in two cohorts - (1) "amyloid +" subjects, defined by biopsy-proven systemic amyloid with associated remodeling suggestive of cardiac involvement (left ventricular [LV] hypertrophy and/or atrial dilation); (2) normative controls without risk factors for amyloid or cardiovascular disease. CMR (1.5T) included 2 components - cine-CMR (SSFP) for cardiac structure/function, and T1 mapping for myocardial tissue characterization. T1 mapping was performed using a conventional modified look locker inversion recovery (MOLLI) sequence (flip angle = 30°; matrix 256 × 128; parallel imaging reduction factor =1.5; linear view ordering; 6 Kaiser-Bessel ramp preparation; 17 heart beat acquisition), with T1 calculated using an established formula (T1 = T1* (B/A-1), T1*, A, and B obtained via three-parameter exponential fit). To test time dependent differences in myocardial T1, MOLLI was acquired at sequential time points (3,5,10,14, 20 minutes) following intravenous administration of gadolinium (0.2 mmol/kg). Results: 10 subjects (5 amyloid, 5 controls) were studied (44 ± 21 years, 40% male); all amyloid affected subjects had biopsy-confirmed disease (4 light chain type, 1 transthyretin). Amyloid subjects had higher LV mass (200 ± 34 vs. 101 ± 34 gm, p = 0.004), lower myocardial contraction fraction (32 ± 8 vs. 88 ± 27, p = 0.002), and larger left atrial area (26 ± 5 vs. 18 ± 5 cm2, p = 0.03) than controls, but similar LV end-diastolic volume (120 ± 24 vs. 133 ± 45 ml, p = 0.61), stroke volume (66 ± 10 vs. 86 ± 30 ml, p = 0.20), and LVEF (56 ± 10 vs. 65 ± 4%, p = 0.11). MOLLI was successfully acquired in all subjects at each time point: T1 differed significantly (all p ≤ 0.05) between amyloid and control groups at all times (Figure 1). However, magnitude of difference temporally decreased following gadolinium administration (Figure 2): T1 differences between patients and controls were maximal at 3 minutes post-contrast (135 ± 15 vs. 310 ± 61 msec, p = 0.004) with progressive decrements thereafter, as evidenced by 57% relative difference between groups at 3 minutes and only a 36% difference at 20 minutes following gadolinium infusion. Figure 1 Mean +/- standard deviation T1 times for healthy controls and amyloid patients Mean +/- standard deviation T1 times for healthy controls and amyloid patients. Figure 2 Percentage T1 difference relative to the healthy mean T1 time Percentage T1 difference relative to the healthy mean T1 time. Conclusions: MOLLI-quantified myocardial T1 yields maximal difference between amyloid-affected subjects and normative controls within 3 minutes following gadolinium administration. Increased magnitude of T1 difference early post contrast may relate to altered gadolinium contrast kinetics due to amyloid-associated increases in cardiac extracellular volume, and/or pulse-sequence aspects of the MOLLI approach. Current findings support use of early post-contrast MOLLI T1 mapping for identification of cardiac amyloid. Funding: M. Cooper was supported by NSF GFRP DGE-0707428. J. Weinsaft was supported by NIH K23HL102249-01

Silencing of WNK2 is associated with upregulation of MMP2 and JNK in gliomas

Matrix metalloproteinases (MMPs) are proteolytic enzymes that degrade extracellular matrix (ECM), thus assisting invasion. Upregulation of MMPs, frequently reported in gliomas, is associated with aggressive behavior. WNK2 is a tumor suppressor gene expressed in normal brain, and silenced by promoter methylation in gliomas. Patients without WNK2 exhibited poor prognosis, and its downregulation was associated with increased glioma cell invasion. Here we showed that MMP2 expression and activity are increased in glioma cell lines that do not express WNK2. Also, WNK2 inhibited JNK, a process associated with decreasing levels of MMP2. Thus, WNK2 promoter methylation and silencing in gliomas is associated with increased JNK activation and MMP2 expression and activity, thus explaining in part tumor cell invasion potential.This work was supported by a Portuguese Foundation for Science and Technology (FCT) projects PTDC/SAU-TOX/114549/2009, and PTDC-SAU-ONC/112511/2009. AMC is a Post-doc Fellow (PTDC/SAU-TOX/114549/2009), and FP is a PhD Fellow (SFRH/BD/81369/2011) from FCT. OM is a Post-doc Fellow from QREN (UMINHO/BPD/32/2013). MJO is an Investigator FCT recipient