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Frank Tappe Christian Schwickert Stefan Linsinger Rainer P?ttgen 《Monatshefte für Chemie / Chemical Monthly》2011,15(2):1087-1095
Abstract
The series of rare earth metal (RE)-rich intermetallics RE 4 TAl and RE 4 TIn (T = Ru, Rh, Ir) were synthesized by induction melting of the elements in sealed tantalum tubes. These compounds crystallize with the cubic Gd4RhIn-type structure, space group F[`4]3mF\bar{4}3m. The structures of eight crystals (including the isotypic compounds Ce4RuMg and Ce4RuCd) have been refined from X-ray single-crystal diffractometer data. The structures are composed of condensed RE 6 T trigonal prisms which form a rigid network with adamantane-like topology. Large cavities within these networks are filled with empty RE 6 octahedra and Al4, In4, Mg4, or Cd4 tetrahedra, respectively. Some of the RE 4 TAl and RE 4 TIn show small homogeneity ranges that result from small degrees of Al/T and In/T mixing on the 16e sites. All cerium compounds show small anomalies in the plots of the cell volumes. This is confirmed by temperature-dependent magnetic susceptibility measurements. Ce4RuMg, Ce4RuCd, Ce4RuAl, and Ce4RuIn show intermediate cerium valence and no magnetic ordering down to 3 K. Ce4RhAl shows essentially trivalent cerium. 相似文献995.
Christian Heller Martin Schwentenwein Günter Russmüller Thomas Koch Doris Moser Christian Schopper Franz Varga Jürgen Stampfl Robert Liska 《Journal of polymer science. Part A, Polymer chemistry》2011,49(3):650-661
The last decade has seen a remarkable interest in the use of biocompatible and biodegradable polymers as scaffolds for tissue engineering. The fabrication of 3D scaffolds by lithography‐based additive manufacturing technology (AMT) represents an appealing approach. As poly(lactic acid), the state of the art biocompatible and biodegradable material, cannot be processed by these photopolymerization‐based techniques, it has so far been necessary to use selected (meth)acrylates. By developing new photopolymers based on vinyl carbonates and vinyl carbamates as a reactive group we have been able to avoid most of the disadvantages of classical (meth)acrylate‐based photopolymers. The new generation of biocompatible monomers show low cytotoxicity, have good storage stability, and are sufficiently photoreactive to be structured by lithography based AMT. The mechanical properties and rates of degradation of the polymers can be easily tuned over a broad range. Degradation results in the formation of nonacidic and nontoxic degradation products of low molecular weight that can be easily transported within the human body. Initial in vivo tests showed significant osseointegration of the 3D cellular scaffolds and no signs of implant rejection. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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Béatrice Roy Isabelle LefebvreJean-Yves Puy Christian Périgaud 《Tetrahedron letters》2011,52(12):1250-1252
We report on the first solution synthesis of lamivudine 5′-diphosphate in both high yield and purity. Efficient synthesis of lamivudine 5′-monophosphate was obtained through lamivudine H-phosphonate oxidation by (−)-(8,8-dichlorocamphorylsulfonyl)oxaziridine.Diphosphorylation was performed by nucleophilic substitution of the phosphorimidazolate derivative of lamivudine. HPLC coupled with UV or MS detection was found to be an invaluable tool for the follow-up of phosphorylation reactions. 相似文献
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