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Les effluents d’élevage ou de l’industrie agroalimentaire, tels que les lisiers, les jus d’ensilage ou les lactosérums, sont des milieux très agressifs pour les ouvrages agricoles en béton. En effet, ces effluents contiennent des bactéries et des acides organiques, deux agents potentiellement agressifs pour la matrice cimentaire. Les objectifs de cet article sont de caractériser les attaques associées à chacun des vecteurs agressifs et de déduire les paramètres de composition des liants favorisant leur durabilité en milieu agricole et agroalimentaire. Des éprouvettes de pâte de ciment ont été immergées dans trois types de solutions : un mélange d’acides organiques, afin d’analyser l’attaque associée à la partie acide des effluents, un lisier et un lactosérum de façon à analyser, pour ces effluents aux pH sensiblement différents, l’effet spécifique des bactéries dans la dégradation. Les modifications chimiques et minéralogiques ont été explorées par des analyses par microsonde électronique et diffraction des rayons X, associées à des observations au microscope électronique à balayage. Les résultats montrent que l’attaque associée à la partie acide des effluents se traduit par une décalcification quasi-totale de la matrice cimentaire, la zone dégradée étant constituée d’un squelette silicoalumineux quasi-amorphe. L’influence de la présence des bactéries sur les modes de dégradation et sur les cinétiques d’altération dépend grandement du pH de l’effluent.

The evaluation of lower gastrointestinal bleeding (LGIB) often involves the collaborative efforts of the gastroenterologist, radiologist, and surgeon. Efforts to localize the acute LGIB have traditionally involved colonoscopy, technetium-labeled red blood cell (RBC) scintigraphy, angiography, or a combination of these modalities. The sensitivity of each method of diagnosis is limited, with the most common cause of a negative study the spontaneous cessation of hemorrhage. Other technical factors include vasospasm, lack of adequate contrast volume or exposure time, a venous bleeding source, and a large surface bleeding area. We report the use of multidetector computed tomography (MDCT), or CT-angiography (CT-A), in the initial evaluation of LGIB, and speculate on the incorporation of this technique into a diagnostic algorithm to treat LGIB. MDCT may offer a very sensitive means to evaluate the source of acute LGIB, while avoiding some of the morbidity and intense resource use of contrast angiography, and may provide unique morphologic information regarding the type of pathology. Screening with the more rapid and available MDCT, followed by either directed therapeutic angiography or surgical management, may represent a reasonable algorithm for the early evaluation and management of acute LGIB in which an active bleeding source is strongly suspected.

Breeding and agrofood effluents, such as liquid manure, silage effluents or lactoserum, are very aggressive environments for agricultural infrastructure made of concrete. Indeed, these effluents contain two types of aggressive vectors: some identified bacteria and several organic acids. This research aims to analyze the mechanisms of chemical and biological attacks on concrete immersed in these effluents. The results are used to identify the compositional parameters of cements that influence their durability in agricultural and agrofood environments. Cement paste specimens were immersed in three types of aggressive solutions. First, a mixture of five organic acids found in liquid manure was used in order to analyse the attack linked with the acidic part of the effluents. Then, two real effluents, liquid manure and lactoserum, were used in order to analyse the specific effect of the bacteria in the alteration. These effluents are characterized by two different ranges of pH. Chemical and mineralogical modifications were explored by electron microprobe, X-ray diffraction analyses, and scanning electron microscopy observations. The degradation of the matrix occurs by almost total decalcification and the probable formation of a silica gel. The influence of the presence of the bacteria on the alteration mechanisms and kinetics greatly depends on the pH of the effluents. Les effluents d??levage ou de l?industrie agroalimentaire, tels que les lisiers, les jus d?ensilage ou les lactos?rums, sont des milieux tr?s agressifs pour les ouvrages agricoles en b?ton. En effet, ces effluents contiennent des bact?ries et des acides organiques, deux agents potentiellement agressifs pour la matrice cimentaire. Les objectifs de cet article sont de caract?riser les attaques associ?es ? chacun des vecteurs agressifs et de d?duire les param?tres de composition des liants favorisant leur durabilit? en milieu agricole et agroalimentaire. Des ?prouvettes de p?te de ciment ont ?t? immerg?es dans trois types de solutions?: un m?lange d?acides organiques, afin d?analyser l?attaque associ?e ? la partie acide des effluents, un lisier et un lactos?rum de fa?on ? analyser, pour ces effluents aux pH sensiblement diff?rents, l?effet sp?cifique des bact?ries dans la d?gradation. Les modifications chimiques et min?ralogiques ont ?t? explor?es par des analyses par microsonde ?lectronique et diffraction des rayons X, associ?es ? des observations au microscope ?lectronique ? balayage. Les r?sultats montrent que l?attaque associ?e ? la partie acide des effluents se traduit par une d?calcification quasi-totale de la matrice cimentaire, la zone d?grad?e ?tant constitu?e d?un squelette silicoalumineux quasi-amorphe. L?influence de la pr?sence des bact?ries sur les modes de d?gradation et sur les cin?tiques d?alt?ration d?pend grandement du pH de l?effluent.

Two series of analogues of riluzole, a blocker of excitatory amino acid mediated neurotransmission, have been synthesized: monosubstituted 2-benzothiazolamines and 3-substituted derivatives. Of all the compounds prepared in the first series, only 2-benzothiazolamines bearing alkyl, polyfluoroalkyl, or polyfluoroalkoxy substituents in the 6-position showed potent anticonvulsant activity against administration of glutamic acid in rats. The most active compounds displaying in vivo “antiglutamate” activity were the 6-OCF3 (riluzole), 6-OCF2CF3, 6-CF3, and 6-CF2CF3 substituted derivatives with ED50 values between 2.5 and 3.2 mg/kg i.p. Among the second series of variously substituted benzothiazolines, compounds as active as riluzole or up to 3 times more potent were identified in two series: benzothiazolines bearing a β-dialkylaminoethyl moiety and compounds with an alkylthioalkyl chain and their corresponding sulfoxides and sulfones. The most potent derivatives were 2-imino-3-(2-methylthio)- and 2-imino-3-(2-methylsulfinyl)-ethyl-6-trifluoromethoxybenzothiazolines (61 and 64, ED50 = 1.0 and 1.1 mg/kg i.p., respectively). In addition, intraperitoneal administration of some of the best benzothiazolines protected mice from mortality produced by hypobaric hypoxia.

Abstract: The Rogaland anorthosite province (S. Norway) contains numerous Fe-Ti oxide deposits, including the second most important ilmenite deposit in the world, the Tellnes deposit. The largest deposits are located in the na-Sira anorthosite massif. Others occur in the Hland-Helleren anorthosite massif, particularly along the deformed contact with the Egersund-Ogna massif, where they were previously considered formed by metasomatic processes. All deposits are now regarded as magmatic. The structure, mineralogy and geochemistry of 11 selected Fe-Ti deposits (Tellnes, Storgangen, Blfjell, Laksedal, Kydlandsvatn, Kagnuden, Rdemyr, Hestnes, Eigery, Svnes, and Jerneld) are discussed in light of recent models proposed for the origin of Rogaland anorthosites and related rocks. Massif-type anorthosites result from the diapiric uprise of a plagioclase crystal mush which crystallized along a large P–T interval. Except for Tellnes, which is related to a post-deformation dyke, the Fe-Ti deposits in anorthosite massifs have been deformed by this movement during and after their crystallization. The differentiation process of the jotunitic parental magma has built up cumulates in the Bjerkreim-Sokndal layered intrusion and liquids in the Tellnes dyke and other jotunitic intrusions. Ilmenite is a liquidus mineral immediately after plagioclase in the sequence of crystallization of these jotunites, its interstitial character in the rocks resulting from subsolidus recrystallization. Ilmenite can thus accumulate early in the evolution of jotunitic magmas. This feature, together with high contents in Cr, V, Mg and Ni, links the Jerneld, Blfjell and Svnes deposits (type␣1) to the early evolution of a jotunitic magma. In the Bjerkreim-Sokndal intrusion, magnetite can appear with ilmenite at the very beginning of the sequence of crystallization, but normally crystallizes after orthopyroxene and before clinopyroxene and apatite. The early appearance of magnetite is a characteristic feature of type 2 deposits (Tellnes, Storgangen, Kydlandsvatn, Rdemyr I) and suggests conditions similar to the early magnetite cumulates in the Bjerkreim-Sokndal intrusion. Evidence of layering further favours gravity-controlled sorting processes to concentrate the oxides. Large-scale subsolidus segregation of the oxides due to high-temperature deformation can further concentrate these minerals in silicate-absent meter-sized masses. Type 3 deposits (Rdemyr II, Kagnuden, Hestnes and Eigery) could be derived from the more evolved stages of differentiation, as indicated by high REE in apatite, high Ti and Zn in magnetite and relatively low Cr, V, Mg, Ni contents in both oxides. The Cr content in both oxide minerals is however higher than in the equivalent cumulates of the Bjerkreim-Sokndal intrusion. Although immiscibility as the mechanism of enrichment leading to silicate-absent oxide-apatite veins, as in Hestnes and Eigery, cannot be precluded, there is no direct evidence in the veins, nor has any structural or geochemical evidence of immiscibility ever been found in jotunite dykes and Fe-Ti-P-rich rocks. Further investigations on the influence of subsolidus exchange of elements between the two oxides are needed to improve the use of trace elements as differentiation indexes.

Abstract: Two major monzonoritic dykes occur in the Egersund-Ogna anorthositic massif (S.W. Norway): the Lomland dyke, which varies from norite to monzonite, and the Vettaland ferronoritic dyke. They are characterized by high Fe, Ti and P contents, low SiO2, variable K2O (0.5%–4.5%) and high Fe/Mg ratios. Small variations in REE distribution are observed inside the Lomland dyke [La/Yb=12; LREE ca. 150–180 (chondrite-normalized values), neutral to slightly positive Eu anomaly]. Part of the Vettaland dyke is severely depleted in Zr, Rb and REE and shows a positive Eu anomaly. All rocks are depleted in U and Th, and show very low Cr and Ni contents, as well as high Sr contents (400–600 ppm). Variation within the Lomland dyke is satisfactorily ex-plained through subtraction of an apatite-bearing noritic cumulate. The role of apatite is predominant in controlling the REE behaviour. Eutectic partial melting of a Fe-rich noritic cumulate (containing apatite) under low pH2O conditions is suggested for the Vettaland dyke by REE modelling. Sr isotopic initial ratios are different in Lomland (ca. 0.708) and Vettaland (ca. 0.706) dykes. These values preclude direct derivation from the mantle as well as comagmatic relationship with anorthosite. Contamination of a mantle derived magma by deep crustal material or anatexis of the LIL depleted lower crust is compatible with the low U and Th contents, and with the Pb isotopic ratios. The Vettaland partial melting process is extended to all monzonoritic types, the necessary heat being provided by the high temperature anorthositic crystal mush.

Fe-sulfides associated with Belgian Pb-Zn vein deposits have been analysed by DC arc spectrometry and XRF for Tl, Ni, Co, Mn, Zn, Pb, Ge, Cd, and As. They show high Tl contents (from >30 ppm upt to 6800 ppm) and Co:Ni ratios <1. These features permit to distinguish them from Fe-sulfides of sedimentary and high temperature occurrences. The Tl distribution in a botryoidal marcasite of Vedrin (average Tl content of 0.68%) has been investigated by ion microprobe. It displays a pattern similar to colloform texture. Principal component analysis shows that the behaviour of Tl is partly controlled by a factor opposing Tl to all other elements. This is interpreted as reflecting the influence of sorption mechanisms by contrast with direct precipitation. Tl and the other elements are not considered of magmatic origin because no acidic magmatism is known during or after Variscan times. Extraction from sedimentary rocks by hydrothermal brines is favoured.

Abstract: More than 200 specimens from different occurrences of the Rogaland igneous complex and surrounding granulite facies metamorphic rocks (S. W. Norway) have been analysed by a direct non-destructive proton induced gamma-ray emission (PIGE) technique. The fluorine contents vary from <25 ppm to 3500 ppm. There is a good correlation between the concentration of fluorine and that of phosphorus for igneous rocks, suggesting a control of apatite on the F content. In metamorphic rocks, amphibole and biotite besides apatite are the principal cencentrators of fluorine indicating that fluorine in the system is controlled by granulite facies metamorphism conditions.

Composition of cement hydration products in concretes made with two condensed silica fumes, three pulverized fly ashes (PFA), and one ground granulated blast furnace slag, and stored at 38°C and 100% relative humidity for 3 years was analyzed using an electron probe microanalyzer. The pore solution expression method was also applied on pastes to analyze the composition of the pore water. The mean CaO/SiO 2 (C/S) mole ration of hydrates in the ordinary Portland cement (OPC) control concrete was 2.05. In blended concretes, this ratio decreased to between 1.24 and 1.46, however with no clear distinction from one supplementary cementing material (SCM) type to another. All blended pastes except the one with the very alkalirich PFA tested showed a drop in the alkali concentration of the pore solution compared with the control paste. Mass balance calculations indicated that lower C/S hydrates produced in the presence of SCM can contain much more alkali than OPC hydrates, provided that more alkali is available. These SCMs may decrease the alkalinity and the pH of the pore solution, and reduce expansion due to alkali silica reactivity.

La méthode de résonance de spin électronique est utilisée pour déterminer l'influence du poids moléculaire des ADN sur le rendement en radicaux libres, lorsque ce composé, en phase solide, est soumis à l'action du rayonnement x. On montre que le rendement en cause est d'autant plus faible que le poids moléculaire est élevé, et cette corrélation est également vérifiée dans les cas du polyéthylène et du polyacrylonitrile.D'autre part, une comparaison des rendements en radicaux libres formés dans les nucléotides et les ADN de différentes dimensions conduit à inférer l'existence d'une sélection radiochimique de ces derniers, au cours de leur évolution moléculaire dans la phase prébiotique. On suggère que ce phénomène pourrait s'identifier à l'un des facteurs régissant les hauts poids moléculaires que l'on observe in vivo.

SOME years ago, Duchesne1suggested that the greater the degree of delocalization of π-electrons, the greater the radio-resistance of solid phase compounds of aromatic type. This was verified by radiolytic yield measurements, using quadrupole spectroscopy and electron spin resonance methods2. B. Pullman3developed similar views in the special field of biomolecules, with particular emphasis on nucleic acid bases, but using molecular resonance energy instead of diamagnetic anisotropy, as had been used, previously, to measure the delocalization effect.

IT is known that spectroscopic data are in agreement only with a series of discrete values for the dissociation energy of carbon monoxide (Dco) and therefore also for the heat of sublimation of carbon (Lc)

IN 1955, Duchesne and Monfils1discovered absorption lines in the frequency-range of 30 Mc./sec. in the sodium salts of deoxyribonucleic acid and nucleo-protein of yeast and of ribonucleic acid of Escherichia coli, all in the dry state, when these substances were inserted in the condenser of a super-regenerative oscillator.