University of Lorraine

About: University of Lorraine is a education organization based out in Nancy, France. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 11942 authors who have published 25010 publications receiving 425227 citations. The organization is also known as: Lorraine University.

The Central Atlantic Magmatic Province (CAMP): A Review

Abstract: The Central Atlantic magmatic province (CAMP) consists of basic rocks emplaced as shallow intrusions and erupted in large lava flow fields over a land surface area in excess of 10 million km2 on the supercontinent Pangaea at about 201 Ma. The peak activity of the CAMP straddled the Triassic-Jurassic boundary and probably lasted less than 1 million years, while late activity went on for several Ma more into the Sinemurian. Emission of carbon and sulfur from the CAMP magmas and from intruded sediments probably caused extinctions at the end-Triassic. Intrusive rocks are represented by isolated dykes up to 800 km-long, by dense dyke swarms and by extremely voluminous sills and a few layered intrusions. Lava fields were erupted as short-lived pulses and can be traced over distances of several hundred km within sedimentary basins. They consist of either compound or simple pahoehoe flows. Globally, the intrusive and effusive rocks are estimated to represent an original magmatic volume of at least 3 million km3. Herein we subdivide the CAMP basalts for the first time into six main geochemical groups, five represented by low-Ti and one by high-Ti rocks. Except for one low-Ti group, which is ubiquitous throughout the entire province, all other groups occur in relatively restricted areas and their compositions probably reflect contamination from the local continental lithosphere. Major and trace elements and Sr-Nd-Pb-Os isotopic compositions indicate that the basaltic magmas had an enriched composition compared to Mid-Ocean Ridge basalts and different from Atlantic Ocean Island basalts. The enriched composition of CAMP basalts is only in part attributable to crustal contamination. It also probably requires subducted upper and lower continental crust material that enriched the shallow upper mantle from which CAMP basalts were generated. A contribution from a deep mantle-plume is not required by geochemical and thermometric data, but it remains unclear what other possible heat source caused mantle melting on the scale required to form CAMP.

The iron-sulfur cluster assembly machineries in plants: current knowledge and open questions

Abstract: Many metabolic pathways and cellular processes occurring in most sub-cellular compartments depend on the functioning of iron-sulfur (Fe-S) proteins, whose cofactors are assembled through dedicated protein machineries. Recent advances have been made in the knowledge of the functions of individual components through a combination of genetic, biochemical and structural approaches, primarily in prokaryotes and non-plant eukaryotes. Whereas most of the components of these machineries are conserved between kingdoms, their complexity is likely increased in plants owing to the presence of additional assembly proteins and to the existence of expanded families for several assembly proteins. This review focuses on the new actors discovered in the past few years, such as glutaredoxin, BOLA and NEET proteins as well as MIP18, MMS19, TAH18, DRE2 for the cytosolic machinery, which are integrated into a model for the plant Fe-S cluster biogenesis systems. It also discusses a few issues currently subjected to an intense debate such as the role of the mitochondrial frataxin and of glutaredoxins, the functional separation between scaffold, carrier and iron-delivery proteins and the crosstalk existing between different organelles.

Gas-phase hydrodeoxygenation of guaiacol over iron-based catalysts. Effect of gases composition, iron load and supports (silica and activated carbon)

Abstract: Fe/SiO2 is shown to be a selective catalyst for guaiacol hydrodeoxygenation (HDO). Guaiacol is used as a model compound to study the conversion of lignin pyrolysis vapours into aromatics (benzene, phenols). The effect of each individual gas present in a pyrolysis gas (H2, CO, CO2, H2O, CH4) on the selectivity of a 10 wt% Fe/SiO2 catalyst is studied (673 K, atmospheric pressure, 50 mol% H2, 1/WHSV = 0.6 gcat h/ggua). The speciation of the iron phase (metallic (α-Fe), carbide (Fe5C2), oxide (Fe3O4), and super-paramagnetic) in spent catalysts is revealed by XRD and Mossbauer spectroscopy as a function of gases composition. At least 3 types of carbonaceous deposit were evidenced by TPO analysis. TEM observations showed that iron particles size is not markedly affected by the reaction and that carbon deposit mainly occurs in the vicinity of iron particles. When all the gases except methane (Guaiacol + H2 + CO + CO2 + H2O) are simultaneously in the feed stream, the conditions are still sufficiently reducing to maintain the activity of the catalyst (66% of benzene and toluene carbon yield, 7.5 gcat h/ggua). The effects of support (silica or activated carbon-AC) and iron loading (5, 10, 15 wt% Fe/SiO2) were also studied. 10 wt% Fe/AC has a higher selectivity in phenol and cresols production than Fe/SiO2. Active sites and reaction mechanisms are discussed.