{\mathcal{N} = 2} Supersymmetric AdS4 Solutions of M-theory

We analyse the most general ${\mathcal{N} = 2}$ supersymmetric solutions of D = 11 supergravity consisting of a warped product of four-dimensional anti-de-Sitter space with a seven-dimensional Riemannian manifold Y ₇. We show that the necessary and sufficient conditions for supersymmetry can be phrased in terms of a local SU(2)-structure on Y ₇. Solutions with non-zero M2-brane charge also admit a canonical contact structure, in terms of which many physical quantities can be expressed, including the free energy and the scaling dimensions of operators dual to supersymmetric wrapped M5-branes. We show that a special class of solutions is singled out by imposing an additional symmetry, for which the problem reduces to solving a second order non-linear ODE. As well as recovering a known class of solutions, that includes the IR fixed point of a mass deformation of the ABJM theory, we also find new solutions which are dual to cubic deformations. In particular, we find a new supersymmetric warped AdS₄ × S ⁷ solution with non-trivial four-form flux.     

Copper(I)-amine metallo-organocatalyzed synthesis of carbo- and heterocyclic systems

The efficient and atom economical synthesis of 5-membered cyclic structures has been achieved through the combination of amino catalysis and metal catalysis. The discovery of a novel metallo-organocatalytic system merging the use of a catalytic copper(I) complex and a catalytic amount of cyclohexylamine allowed the room temperature preparation of a broad range of skeletons such as cyclopentanes, indanes, pyrrolidines and tetrahydrofuran, important structural cores of many biologically relevant molecules. Mechanistic studies were presented.     

Human Elastin‐Based Recombinant Biopolymers Improve Mesenchymal Stem Cell Differentiation

Elastin‐based polypeptides are a class of smart biopolymers representing an important model in the design of biomaterials. The combination of biomimetic materials with cells that have great plasticity provides a promising strategy for the realization of highly engineered cell‐based constructs for regenerative medicine and tissue repair applications. Two recombinant biopolymers inspired by human elastin are assessed as coating agents to prepare biomimetic surfaces for cell culture. These substrates are assayed for hBM MSC culture. The coated surfaces are also characterized with AFM to evaluate the topographical features of the deposited biopolymers. The results suggest that the elastin‐derived biomimetic surfaces play a stimulatory role on osteogenic differentiation of MSCs.

     

New labdane diterpenes from the stem bark of Larix laricina

Two new labdane diterpenes, cis-19-hydroxyabienol (1) and 8alpha-hydroxy-12Z,14-labdadien-19-al (2), along with another labdane described for the first time in the genus Larix, 19-acetoxy-13S-hydroxy-8(17),14-labdadiene (3) and a stilbene, 3-methoxy-3,3',5'-trihydroxystilbene (4), were isolated from the stem bark of Larch (Larix laricina). Their structures were established by standard chemical and spectroscopic methods. Compounds 2 and 3 were shown to be moderately cytotoxic against A-549, DLD-1 and normal skin fibroblast cell lines, WS1. Compound 1 was found to be selectively active against colon carcinoma cell lines, DLD-1.     

A double-stage tube furnace—acid-trapping protocol for the pre-concentration of mercury from solid samples for isotopic analysis

High-precision mercury (Hg) stable isotopic analysis requires relatively large amounts of Hg (>10 ng). Consequently, the extraction of Hg from natural samples with low Hg concentrations (<1–20 ng/g) by wet chemistry is challenging. Combustion–trapping techniques have been shown to be an appropriate alternative [1]. Here, we detail a modified off-line Hg pre-concentration protocol that is based on combustion and trapping. Hg in solid samples is thermally reduced and volatilized in a pure O₂ stream using a temperature-programmed combustion furnace. A second furnace, kept at 1,000 °C, decomposes combustion products into H₂O, CO₂, SO₂, etc. The O₂ carrier gas, including combustion products and elemental Hg, is then purged into a 40 % (v/v) acid-trapping solution. The method was optimized by assessing the variations of Hg pre-concentration efficiency and Hg isotopic compositions as a function of acid ratio, gas flow rate, and temperature ramp rate for two certified reference materials of bituminous coals. Acid ratios of 2HNO₃/1HCl (v/v), 25 mL/min O₂ flow rate, and a dynamic temperature ramp rate (15 °C/min for 25–150 and 600–900 °C; 2.5 °C/min for 150–600 °C) were found to give optimal results. Hg step-release experiments indicated that significant Hg isotopic fractionation occurred during sample combustion. However, no systematic dependence of Hg isotopic compositions on Hg recovery (81–102 %) was observed. The tested 340 samples including coal, coal-associated rocks, fly ash, bottom ash, peat, and black shale sediments with Hg concentrations varying from <5 ng/g to 10 μg/g showed that most Hg recoveries were within the acceptable range of 80–120 %. This protocol has the advantages of a short sample processing time (～3.5 h) and limited transfer of residual sample matrix into the Hg trapping solution. This in turn limits matrix interferences on the Hg reduction efficiency of the cold vapor generator used for Hg isotopic analysis.     

The Photocatalyzed Thiol-ene reaction: A New Tag to Yield Fast,Selective and reversible Paramagnetic Tagging of Proteins

Paramagnetic restraints have been used in biomolecular NMR for the last three decades to elucidate and refine biomolecular structures, but also to characterize protein-ligand interactions. A common technique to generate such restraints in proteins, which do not naturally contain a (paramagnetic) metal, consists in the attachment to the protein of a lanthanide-binding-tag (LBT). In order to design such LBTs, it is important to consider the efficiency and stability of the conjugation, the geometry of the complex (conformational exchanges and coordination) and the chemical inertness of the ligand. Here we describe a photo-catalyzed thiol-ene reaction for the cysteine-selective paramagnetic tagging of proteins. As a model, we designed an LBT with a vinyl-pyridine moiety which was used to attach our tag to the protein GB1 in fast and irreversible fashion. Our tag T1 yields magnetic susceptibility tensors of significant size with different lanthanides and has been characterized using NMR and relaxometry measurements.     

A new reaction calorimeter and calorimetric tools for safety testing at laboratory scale

Calorimetry combined with thermal analysis is an essential tool for the evaluation of thermal risks linked with chemical reactions at industrial scale. The energies of synthesis reactions or decomposition reactions as well as the heat capacities of reaction masses can be measured using such techniques. The capacity of the SETARAM differential reaction calorimeter (DRC) to determine essential safety data has been demonstrated with the measurement of heat capacities of cyclohexane and propanoic acid. Results of an industrial reaction are also presented.     

High extraction efficiency,laterally injected,light emitting diodes combining microcavities and photonic crystals

The use of photonic crystals (PCs) for realistic light emitting diodes (LEDs) is discussed, given the constraints of planar semiconductor technology. A viable route for the fabrication of high-efficiency high-brightness electrically injected LEDs is presented. The starting point is a top-emitting microcavity using a single Alox Bragg mirror. The active area is surrounded by two-dimensional PCs, namely arrays of air rods etched through the top layers; injection of the electrons is achieved through the crystals. Design rules for PCs as efficient out-couplers are detailed. The building blocks are assessed experimentally, and we show that promising results are at hand.