Réactivité de l’acide déhydroacétique hydrogené en c5-c6 : obtention des pyrano-1,5-benzodiazépines différemment substituées et de la structure enaminone

A number of 1,5-benzodiazepines derivatives 4 were obtained via the interaction of dehydroacetic acid hydrogenated at C₅-C₆, orthophenylenediamines and aromatic aldehydes. The interpretation of the results is enriched by a study of the electronic effects of the DHA hydrogenated at C₅-C₆. Accordingly, it leads us to obtain the original structure cynnamoyle 5.     

Targeting the proangiogenic VEGF-VEGFR protein-protein interface with drug-like compounds by in silico and in vitro screening

Protein-protein interactions play a central role in medicine, and their modulation with small organic compounds remains an enormous challenge. Because it has been noted that the macromolecular complexes modulated to date have a relatively pronounced binding cavity at the interface, we decided to perform screening experiments over the vascular endothelial growth factor receptor (VEGFR), a validated target for antiangiogenic treatments with a very flat interface. We focused the study on the VEGFR-1 D2 domain, and 20 active compounds were identified. These small compounds contained a (3-carboxy-2-ureido)thiophen unit and had IC₅₀ values in the low micromolar range. The most potent compound inhibited the VEGF-induced VEGFR-1 transduction pathways. Our findings suggest that our best hit may be a promising scaffold to probe this macromolecular complex and for the development of treatments of VEGFR-1-dependent diseases.     

Chemical composition and biological potential of seed oil and leaf extracts of Henophyton deserti Coss. & Durieu

Henophyton deserti was characterized in respect to its chemical composition, antioxidant potential and antimicrobial activity. Fourteen compounds were identified by LC/MS, GC/MS, and GC in leaf and seed extracts. Total flavonoids ranged between 45.66 and 181.2 mg QE g^?1 and 2.03 and 38.95 mg QE g^?1 dry weight (dw) in leaf and seed polar extracts, respectively. Rutin, Kaempferol 3-rutinoside, Diosmetin 7-O-Glucoside, and Acacetin 7-O-Glucoside flavonoids were tentatively identified in this plant. The profile of seed fatty acids revealed oleic acid (C18:1, 27%), linoleic acid (C18:2, 12%) and linolenic acid (C18:3, 17%). The highest antioxidant activities of 85.2% and 67.5% were obtained with methanol and ethyl acetate leaf extracts. All H. deserti extracts were active against at least one of the tested bacteria, leaf ethyl acetate extract showed the lowest MIC of 0.156 mg ml^?1. Only seed ethyl acetate extract showed antifungal activity with a MIC of 2.5 mg ml^?1.     

Synthesis and crystal structure determination of yttrium ultraphosphate YP5O14

The crystal structure of monoclinic YP₅O₁₄ (space group C2/c, a=12.919(2) Å, b=12.796(4) Å, c=12.457(2) Å, β=91.30(1)°, Z=8) has been refined from single-crystal X-ray diffraction data. Full-matrix least-squares refinement on F² using 2249 independent reflections for 183 refinable parameters results in a final R value of 0.027 (ωR=0.069). The structure is isotypic with HoP₅O₁₄. This structure is built up from infinite layers of PO₄ tetrahedra linked through isolated YO₈ polyhedra. The three-dimensional cohesion of the framework results from Y-O-P bridges. This crystal structure refinement leads to the calculated X-ray diffraction powder pattern of this monoclinic polymorph, which has been the starting point of a thorough study of the solid-state synthesis of this ultraphosphate. This investigation further leads to a better outstanding of features observed during the synthesis of powdered samples. The thermal behavior of this ultraphosphate has been studied by DTA and TGA analyses. The infrared and Raman spectroscopic characterizations have been carried out on polycrystalline samples. The luminescence properties of the Eu³⁺ ion incorporated in the monoclinic C2/c polymorph of YP₅O₁₄ as local structural probe show that in YP₅O₁₄: 5% Eu³⁺ sample, the Eu³⁺ ions are distributed over the two Y³⁺ crystallographic sites of C₂ symmetry of this structure.     

Micromechanical modelling and simulation of chopped random fiber reinforced polymer composites with progressive debonding damage

The aim of the present paper is to provide a quantitative prediction of the elastic-damage behaviour of randomly oriented fiber polymer composites. A constitutive model based on micromechanical considerations is presented. The nucleation and growth of voids induced by progressive fiber debonding is combined with the constitutive relationship. Failure resulting of excessive damage accumulation is captured by a critical void volume criterion and a vanishing element technique. Experimentally, damage accumulation in random glass fiber–polyester composites was monitored by a videoextensometry technique able to control the local strain rate. Good agreement of model predictions with experimental data is pointed out. The model was implemented into a finite element program and numerical applications on composite structures (a tensile specimen and a plate containing a central hole) are presented to illustrate the capability of the approach. Digital image correlation method was also used to measure the full-field strain in a notched specimen under tensile loading. The simulated results compared favourably with those obtained from experiments.     

Sequential MCR/Fisher indolization strategy for the construction of polycyclic carbazole derivatives

A one-pot method for the synthesis of novel polycyclic carbazole derivatives from readily available starting materials using a sequential multicomponent reaction/Fisher indolization strategy is described.     

Join-Irreducible Boolean Functions

This paper is a contribution to the study of a quasi-order on the set Ω of Boolean functions, the simple minor quasi-order. We look at the join-irreducible members of the resulting poset [(W)\tilde]\tilde{\Omega}. Using a two-way correspondence between Boolean functions and hypergraphs, join-irreducibility translates into a combinatorial property of hypergraphs. We observe that among Steiner systems, those which yield join-irreducible members of [(W)\tilde]\tilde{\Omega} are the − 2-monomorphic Steiner systems. We also describe the graphs which correspond to join-irreducible members of [(W)\tilde]\tilde{\Omega}.     

Etude du polymorphisme des orthophosphates de lithium et de zinc

A partial study of the Li₂O-P₂O₅ and ZnO-P₂O₅ binary diagrams led to establishment of the polymorphism of Li₃PO₄ and of Zn₃(PO₄)₂. Three crystalline forms were found for Li₃PO₄, differring from one another only on the cation distribution at the tetrahedral sites of the almost hexagonal compact arrangement of the anions. Li₃PO₄ differs from the isostructural compounds Li₃VO₄ and Li₃AsO₄ in its irreversible transformation at low temperature. Zn₃(PO₄)₂ is dimorphic, with a reversible transformation. It displays a slight non-stoichiometry through a ZnO deficiency.

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Zusammenfassung Aufgrund einer teilweisen Untersuchung der binären Diagramme von Li₂O-P₂O₅ und ZnO-P₂O₅ konnte der Polymorphismus der Verbindungen Li₃PO₄ und Zn₃(PO₄)₂ näher beschrieben werden. Für Lithiumorthophosphat wurden drei kristalline Formen gefunden. Sie unterscheiden sich voneinander nur in der Kationenverteilung in den tetraedrischen Gebilden der fast hexagonal kompakten Anordnung der Anionen. Li₃PO₄ unterscheidet sich von den isostrukturellen Verbindungen Li₃VO₄ und Li₃AsO₄ durch seinen irreversiblen Übergang bei niedriger Temperatur. Zinkorthophosphat ist dimorph und zeigt eine reversiblen Umwandlung. Es weist wegen ZnO-Mangels eine geringe Abweichung von der stöchiometrischen Zusammensetzung auf.

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In situ 3D Synchrotron Laminography Assessment of Edge Fracture in Dual-Phase Steels: Quantitative and Numerical Analysis

The mechanical performance of automotive structures made of advanced high strength steels (AHSS) is often seen reduced by the presence of cut edges. An attempt is made to assess and quantify the initial damage state and the damage evolution during mechanical testing of a punched edge and a machined edge via a recently developed 3D imaging technique called synchrotron radiation computed laminography. This technique allows us to observe damage in regions of interest in thin sheet-like objects at micrometer resolution. In terms of new experimental mechanics, steel sheets having sizes and mechanical boundary conditions of engineering relevance can be tested for the first time with in situ 3D damage observation and quantification. It is found for the investigated DP600 steel that the fracture zone of the punched edge is rough and that needle-shape voids at the surface and in the bulk follow ferrite-martensite flow lines. During mechanical in situ testing the needle voids grow from the fracture zone surface and coalesce with the sheared zone. In contrast, during in situ mechanical testing of a machined edge the damage starts away from the edge (～800μm) where substantial necking has occurred. Three-dimensional image analysis was performed to quantify the initial damage and its evolution. These data can be used as input and validation data for micromechanical damage models. To interpret the experimental findings in terms of mechanical fields, combined surface digital image correlation and 3D finite element analysis were carried out using an elasto-plastic constitutive law of the investigated DP steel. The stress triaxiality and the accumulated plastic strain were calculated in order to understand the influence of the edge profile and the hardening of the cutting-affected zone on the mechanical fields.