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Nicholas P. Calta Dr. Jino Im Alexandra P. Rodriguez Dr. Lei Fang Dr. Daniel E. Bugaris Dr. Thomas C. Chasapis Prof. Arthur J. Freeman Prof. Mercouri G. Kanatzidis 《Angewandte Chemie (International ed. in English)》2015,54(32):9186-9191
EuIr4In2Ge4 is a new intermetallic semiconductor that adopts a non‐centrosymmetric structure in the tetragonal ${I\bar 42m}$ space group with unit cell parameters a=6.9016(5) Å and c=8.7153(9) Å. The compound features an indirect optical band gap Eg=0.26(2) eV, and electronic‐structure calculations show that the energy gap originates primarily from hybridization of the Ir 5d orbitals, with small contributions from the Ge 4p and In 5p orbitals. The strong spin–orbit coupling arising from the Ir atoms, and the lack of inversion symmetry leads to significant spin splitting, which is described by the Dresselhaus term, at both the conduction‐ and valence‐band edges. The magnetic Eu2+ ions present in the structure, which do not play a role in gap formation, order antiferromagnetically at 2.5 K. 相似文献
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The addition of lithium benzylthiolates to Nα,-formyl-α,β-dehydro-α-amino acid esters gave protected Nα-formyl-β-S-benzyl-β,β-dialkylcysteine esters. Hydrolysis and Nα-protection produced β,β-dialkyl-cysteines which can be used for peptide synthesis. 相似文献
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Radical S‐Adenosyl Methionine Epimerases: Regioselective Introduction of Diverse D‐Amino Acid Patterns into Peptide Natural Products 下载免费PDF全文
Dr. Brandon I. Morinaka Dr. Anna L. Vagstad Maximilian J. Helf Dr. Muriel Gugger Dr. Carsten Kegler Dr. Michael F. Freeman Prof. Dr. Helge B. Bode Prof. Dr. Jörn Piel 《Angewandte Chemie (International ed. in English)》2014,53(32):8503-8507
PoyD is a radical S‐adenosyl methionine epimerase that introduces multiple D ‐configured amino acids at alternating positions into the highly complex marine peptides polytheonamide A and B. This novel post‐translational modification contributes to the ability of the polytheonamides to form unimolecular minimalistic ion channels and its cytotoxic activity at picomolar levels. Using a genome mining approach we have identified additional PoyD homologues in various bacteria. Three enzymes were expressed in E. coli with their cognate as well as engineered peptide precursors and shown to introduce diverse D ‐amino acid patterns into all‐L peptides. The data reveal a family of architecturally and functionally distinct enzymes that exhibit high regioselectivity, substrate promiscuity, and irreversible action and thus provide attractive opportunities for peptide engineering. 相似文献
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The gate surfaces of ion‐sensitive field‐effect transistor (ISFET) devices were functionalized with the π‐donor units, 6‐hydroxydopamine ( 1 ) or 4‐aminothiophenol ( 2 ). Concentration of trinitrotoluene, TNT, on the gate via π‐donor‐acceptor interactions yields charge‐transfer complexes that alter the gate potential. This enables the label‐free analysis of TNT with a detection limit corresponding to 1×10?7 M. 相似文献
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R.M. Freeman F. Haas M.-P. Nicoli A. Morsad Z. Basrak 《The European Physical Journal A - Hadrons and Nuclei》1999,4(3):239-244
It has been noticed that a distinct resemblance exists at large angles among angular distributions measured for reaction
channels at the energies of some resonance-like structures in the 12C+12C and 14C+16O systems. It is pointed out that such forms are typical of a diffraction pattern of a broad band of coherent partial waves.
Received: 5 October 1998 / Revised version: 8 December 1998 相似文献
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