Syntheses and Applications of Monofluorinated Cyclopropanes

The combination of a fluorine atom and a cyclopropane ring, which both possess unique structural and chemical features, can generate new relevant building blocks for the discovery of efficient fluorinated biologically active agents. In this review, we report the different strategies to access monofluorocyclopropanes and highlight some of their attractive biological applications.     

Mass spectrometric characterization of tamoxifene metabolites in human urine utilizing different scan parameters on liquid chromatography/tandem mass spectrometry

Different liquid chromatographic/tandem mass spectrometric (LC/MS/MS) scanning techniques were considered for the characterization of tamoxifene metabolites in human urine for anti‐doping purpose. Five different LC/MS/MS scanning methods based on precursor ion scan (precursor ion scan of m/z 166, 152 and 129) and neutral loss scan (neutral loss of 72 Da and 58 Da) in positive ion mode were assessed to recognize common ions or common losses of tamoxifene metabolites. The applicability of these methods was checked first by infusion and then by the injection of solution of a mixture of reference standards of four tamoxifene metabolites available in our laboratory. The data obtained by the analyses of the mixture of the reference standards showed that the five methods used exhibited satisfactory results for all tamoxifene metabolites considered at a concentration level of 100 ng/mL, whereas the analysis of blank urine samples spiked with the same tamoxifene metabolites at the same concentration showed that the neutral loss scan of 58 Da lacked sufficient specificity and sensitivity. The limit of detection in urine of the compounds studied was in the concentration range 10–100 ng/mL, depending on the compound structure and on the selected product ion. The suitability of these approaches was checked by the analysis of urine samples collected after the administration of a single dose of 20 mg of tamoxifene. Six metabolites were detected: 4‐hydroxytamoxifene, 3,4‐dihydroxytamoxifene, 3‐hydroxy‐4‐methoxytamoxifene, N‐demethyl‐4‐hydroxytamoxifene, tamoxifene‐N‐oxide and N‐demethyl‐3‐hydroxy‐4‐methoxytamoxifene, which is in conformity to our previous work using a time‐of‐flight (TOF) mass spectrometer in full scan acquisition mode. Copyright © 2010 John Wiley & Sons, Ltd.     

Experimental Investigation of Concrete Packages for Radioactive Waste Management: Permeability and Influence of Junctions

We studied the feasibility of a concrete package for radioactive waste management in a joint program involving Andra (the French agency for radioactive waste management) and CEA (the French atomic energy commission). The package??s long-term durability and radionuclides?? containment were the major concerns. The presence of junctions between the prefabricated body and the poured-in-place lids was identified as a major weakness. The first objective of this study was to characterize the permeability of the selected concrete and of the package itself (that is to say accounting for the junctions influence). We used special specimens including a junction, and tested three different surface preparation methods. The second objective was to assess the influence of the manufacturing conditions (laboratory and industrial) on permeability.     

Frontal free‐radical photopolymerization of thick samples: Applications to LED‐induced fiber‐reinforced polymers

Free‐radical photopolymerization is scarcely used for the manufacturing of fiber‐reinforced polymers. The main issue relies on the penetration depth of light which affects the conversion degree when photopolymerizing thick samples. Consequently, this could lead to inhomogeneous polymer properties. The ability of acylphosphine oxides to photobleach under near UV irradiation makes them of great interest for the curing of thick samples. Therefore, the influence of (2,4,6‐trimethylbenzoyl) phosphine oxide on the curing of composites under LED is investigated. Although that a frontal photopolymerization process can be evidenced, it was found that full photobleaching is hardly obtained at high concentration of photoinitiator. Six layers laminates made of unidirectional fiber glass and unsaturated polyester resin were prepared. The existence of an optimal range of concentration for which the conversion of the resin is the most homogeneous throughout its thickness was pointed out, a fact that is confirmed by dynamic mechanical analysis. Interestingly, this effect is reflected in the shrinkage of the resin as shown by direct measurements or deflection experiments. Mechanical analysis was undertaken whose results correlate well with the aforementioned study, demonstrating the occurrence of a balance between the concentration of photoinitiator and the mechanical properties of the samples. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 898–906     

A two‐phase adaptive finite element method for solid–fluid coupling in complex geometries

In this paper we present a method to solve the Navier–Stokes equations in complex geometries, such as porous sands, using a finite‐element solver but without the complexity of meshing the porous space. The method is based on treating the solid boundaries as a second fluid and solving a set of equations similar to those used for multi‐fluid flow. When combined with anisotropic mesh adaptivity, it is possible to resolve complex geometries starting with an arbitrary coarse mesh. The approach is validated by comparing simulation results with available data in three test cases. In the first we simulate the flow past a cylinder. The second test case compares the pressure drop in flow through random packs of spheres with the Ergun equation. In the last case simulation results are compared with experimental data on the flow past a simplified vehicle model (Ahmed body) at high Reynolds number using large‐eddy simulation (LES). Results are in good agreement with all three reference models. Copyright © 2010 John Wiley & Sons, Ltd.