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Bellemin-Laponnaz S.,CNRS Institute of Genetics and of Molecular and Cellular Biology | Bellemin-Laponnaz S.,University of Strasbourg | Dagorne S.,CNRS Strasbourg Institute of Chemistry
Chemical Reviews | Year: 2014

Early transition metal N-Heterocyclic carbenes (NHC) complexes in catalysis remain a field to be explored and developed taking advantage of the robustness/stability imparted to the resulting metal-based catalytically active components. Recent and promising reports on the use of early transition metal NHC complexes in homogeneous catalysis include, most notably, their ability to effectively mediate ketone hydrosilylation, olefin/cyclic esters polymerization, and olefin hydroamination reactions. Recent developments in carbene lithium compounds includevthe isolation and structural characterization of Li+ adductsvbearing abnormal NHCs. In related studies on anionic NHCs, Lavallo and co-workers visolated and characterized a number of Li salts of carborane-containing NHC anions starting from a formally monoanionic carborane N-functionalized imidazolium salt as the protio ligand. Other examples of lithium and potassium NHC compounds have been reported and typically include polydentate ligands incorporating a carbene ligand with an anionic functional group and variously functionalized monodentate NHC ligands. Source


Banhart F.,CNRS Institute of Genetics and of Molecular and Cellular Biology
Beilstein Journal of Nanotechnology | Year: 2015

Linear strings of Sp1-hybridized carbon atoms are considered as a possible phase of carbon since decades. Whereas the debate about the stability of the corresponding bulk phase carbyne continues until today, the existence of isolated chains of carbon atoms has meanwhile been corroborated experimentally. Since graphene, as the two-dimensional Sp2-bonded allotrope of carbon, has become a vast field, the question about the importance of one-dimensional carbon became of renewed interest. The present article gives an overview of the work that has been carried out on chains of carbon atoms in the past one or two decades. The review concentrates on isolated chains of carbon atoms and summarizes the experimental observations to date. While the experimental information is still very limited, many calculations of the physical and chemical properties have been published in the past years. Some of the most important theoretical studies and their importance in the present experimental situation are reviewed. © 2015 Banhart licensee Beilstein-Institut. Source


Carrado A.,CNRS Institute of Genetics and of Molecular and Cellular Biology
ACS Applied Materials and Interfaces | Year: 2010

Plasma-spray (PS) is a classical technique usually employed to cover orthopaedic titanium implant surfaces with hydroxyapatite (HA - Ca10(PO 4) 6(OH) 2). The objective of the current study is to investigate the structure and microstructure of HA plasma-spray 50 μm thick coating on titanium alloy (Ti-6Al-4 V) and residual stress due to processing in the substrate and in HA coating. The structure of the coatings was determined by high-energy synchrotron X-ray diffraction in energy dispersive (HESXRD), selected area electron diffraction (saed), Scanning Electron Microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). No impurity phases in the HA were identified by HESXRD to keep away from the decomposition of HA at high temperature. hcp phase of HA substrate was detected with slight amorphous background. FTIR spectrum of a HA powder shows a typical spectrum for HA material with the characteristic phosphate peaks for HA at wavenumbers of 1090, 1052, 963, 602, and 573 cm -1 are present. The morphology of HA powder observed by SEM exhibits grains of ca. 0.1 μmwell-adapted for cell proliferation. HA/Ti-6Al-4 V interface observed by cross-section scanning and transmission electronmicroscopy (TEM) presentsmicrocracks. Residual stresses were analyzed by sin 2 ψ X-ray diffraction method on titanium substrates and HA coating. Although the Ti substrates are in a slightly tensile residual state, the coated ones show a compressive state. © 2010 American Chemical Society. Source


Bailleul M.,CNRS Institute of Genetics and of Molecular and Cellular Biology
Applied Physics Letters | Year: 2013

We show that the propagation of microwave fields along a planar transmission line is strongly modified when a conducting film is brought close to it. The effect is attributed to the shielding of the electrical and/or magnetic microwave fields which is shown to occur over a wide range of parameters (microwave frequency, film square resistance, transverse dimensions of the waveguide). This is illustrated by finite-element electromagnetic simulations and interpreted using a distributed impedance model. We discuss the implications of this phenomenon for broadband measurements of ferromagnetic resonance realized by placing a ferromagnetic metal film above a coplanar waveguide. © 2013 AIP Publishing LLC. Source


Sexton T.,CNRS Institute of Genetics and of Molecular and Cellular Biology | Cavalli G.,Institute of Human Genetics IGH
Cell | Year: 2015

The genome must be highly compacted to fit within eukaryotic nuclei but must be accessible to the transcriptional machinery to allow appropriate expression of genes in different cell types and throughout developmental pathways. A growing body of work has shown that the genome, analogously to proteins, forms an ordered, hierarchical structure that closely correlates and may even be causally linked with regulation of functions such as transcription. This review describes our current understanding of how these functional genomic "secondary and tertiary structures" form a blueprint for global nuclear architecture and the potential they hold for understanding and manipulating genomic regulation. © 2015 Elsevier Inc. Source

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