Catalytic methylation of aromatic amines with formic acid as the unique carbon and hydrogen source

International audienceA novel methodology is presented for the direct methylation of amines, using formic acid as a unique source of carbon and hydrogen. Based on ruthenium(II) catalysts, the formation of the N-CH3 group proceeds via an efficient formylation/transfer hydrogenation pathwa

Determination of soot volume fraction and particle size distribution in turbulent non- premixed butane and ethylene jet flames through LII, PPS and SMPS measurements

International audienceThe present work reports soot volume fraction determined in turbulent sooting non-premixed jet flames using a Pegasor particle sensor (PPS) and also using the non-intrusive laser-induced incandescence (LII) technique. Additionally, soot particle size distribution is determined using Scanning Mobility Particle Sizer (SMPS). Turbulent flames with different fuels, namely: butane (Re = 26,000), 70% butane + 30% ethylene by volumes (Re = 20,000), and ethylene (Re = 10,000) are investigated. The axial distribution of PPS derived soot volume fraction is qualitatively in excellent agreement with that obtained using LII. The possible sources of quantitative discrepancy between soot concentration obtained through LII and that of the PPS are discussed. Axial evolution of the soot size along with the volume fraction is presented. These results form part of the proposed comprehensive database to validate advanced soot models

Proposal for a Standardization of Mathematical Function Implementation in Floating-Point Arithmetic

Some aspects of what a standard for the implementation of the mathematical functions could be are presented. Firstly, the need for such a standard is motivated. Then the proposed standard is given. The question of roundings constitutes an important part of this paper: three levels are proposed, ranging from a level relatively easy to attain (with fixed maximal relative error) up to the best quality one, with correct rounding on the whole domain of every function. We do not claim that we always suggest the right choices, or that we have thought about all relevant issues. The mere goal of this paper is to raise questions and to launch the discussion towards a standard

MPFR: A Multiple-Precision Binary Floating-Point Library With Correct Rounding

This paper presents a multiple-precision binary floating-point library, written in the ISO C language, and based on the GNU MP library. Its particularity is to extend ideas from the IEEE-754 standard to arbitrary precision, by providing correct rounding and exceptions. We demonstrate how these strong semantics are achieved | with no signicant slowdown with respect to other tools | and discuss a few applications where such a library can be useful

SPECTRAL CLUSTERING BASED PARCELLATION OF FETAL BRAIN MRI

Many neuroimaging studies are based on the idea that there are distinct brain regions that are functionally or micro-anatomically homogeneous. Obtaining such regions in an au-tomatic way is a challenging task for fetal data due to the lack of strong and consistent anatomical features at the early stages of brain development. In this paper we propose the use of an automatic approach for parcellating fetal cerebral hemi-spheric surfaces into K regions via spectral clustering. Unlike previous methods, our technique has the crucial advantage of only relying on intrinsic geometrical properties of the corti-cal surface and thus being unsupervised. Results on a data-set of fetal brain MRI acquired in utero demonstrated a convinc-ing parcellation reproducibility of the cortical surfaces across fetuses with varying gestational ages and folding magnitude

CO2_2 Conversion to Esters by Fluoride-mediated Carboxylation of Organosilanes and Halide Derivatives

International audienceThe one-step conversion of CO$_2$ to hetero-aromatic esters is presented under metal-free conditions. Using fluoride anions as promoters for C-Si bond activation, pyridyl, furanyl and thiophenyl organosilanes are successfully carboxylated with CO$_2$, in the presence of an electrophile. The mechanism of this unprecedented reaction has been elucidated based on experimental and computational results, which show a unique catalytic influence of CO$_2$ in the C-Si bond activation of pyridylsilanes. The methodology is applied to 18 different esters and it has enabled the incorporation of CO$_2$ to a polyester material, for the first time

Classical pathway activity C3c, C4 and C1-inhibitor protein reference intervals determination in EDTA plasma

Introduction: Reference intervals (RIs) for complement assays in EDTA plasma samples have not previously been published. The objectives of the present study were to validate and/or determine RIs for classical pathway (CP50) activity and C3c, C4 and C1 inhibitor protein (C1INH) assays and to assess the need for age-specific RIs in EDTA plasma. Materials and methods: We retrospectively evaluated a cohort of 387 patients attending our university hospital and known to be free of complement- modifying diseases. The need for age partitioning was assessed and RIs were calculated according to the CLSI protocol. Results: No need for age partitioning was evidenced for CP50 activity, C3c and C4 concentrations and RIs (90% CI) were calculated from the pooled data: 35.4 (33.1-37.2) to 76.3 (73.7-83.6) U/mL for CP50 activity, 0.80 (0.75-0.87) to 1.64 (1.59-1.72) g/L for C3c, and 0.12 (0.10-0.14) to 0.38 (0.36- 0.40) g/L for C4. Our results highlight a positive association between age and C1INH concentrations. We derived 3 age partitions (6 months to 30 years, 30-50 and > 50 years) and the related RIs: 0.20 (0.18-0.21) to 0.38 (0.36-0.40) g/L, 0.22 (0.20-0.24) to 0.39 (0.36-0.41) g/L and 0.25 (0.22-0.27) to 0.41 (0.40-0.43) g/L, respectively). Conclusions: The newly determined RIs for CP50 activity were higher than those provided by the manufacturer for EDTA plasma samples, whereas those for C3c and C4 RIs were similar to the values provided for serum samples. The C1INH concentration and activity were found to be associated with age and age-specific RIs are mandatory for this analyte

Reconnaître et caractériser les zones de forge sur surface décapée. Apport de la géophysique à l’étude paléométallurgique

La fouille et l’étude approfondie des sites liés à la métallurgie du fer sont relativement fréquentes. Elles sont généralement menées lorsque l’activité sidérurgique présente des dimensions importantes et que des vestiges caractéristiques sont observables. On pense, par exemple, aux sites de production de fer et à la découverte de restes de bas fourneaux ou de structures de rejet caractéristiques (ferriers). Il en est de même pour les lieux de post-réduction qui ne sont généralement étudiés q..

Elucidating dramatic ligand effects on SET processes: iron hydride versus Iron borohydride catalyzed reductive radical cyclization of unsaturated organic halides

An iron(II) borohydride complex ([(η1-H3BH)FeCl(NCCH3)4]) is employed as the precatalyst in iron-catalyzed radical cyclizations of unsaturated organic halides in the presence of NaBH4. Mechanistic investigations have established that the ligand bound to the metal center (acetonitrile versus ethylenebis(diphenylphosphine) (dppe)) plays a crucial role in the structure and reactivity of the active anionic iron(I) hydride ([HFeCl(dppe)2]−) and borohydride ([(η1-H3BH)FeCl(NCCH3)4]−) with unsaturated haloacetals. This work provides new insights into iron(I) hydride and borohydride species and their potential implication in single-electron processes