Optical transitions in magnetoelectric Ga0.6Fe1.4O3 from 0.73 to 6.45 eV

The optical properties of polycrystalline Ga0.6Fe1.4O3 bulk are determined by spectroscopic ellipsometry from 0.73 to 6.45 eV. Complex dielectric function epsilon = epsilon(1) + i epsilon(2) spectra are obtained from the multilayer analysis. The ellipsometric data exhibit numerous optical structures, and the transition energies are accurately obtained by analyzing the second-energy derivatives of the data. The origins of the optical structures are explained in terms of Fe3+ ligand field transitions and ligand-to-metal charge transfer transitions. (C) 2012 American Vacuum Society. [http://dx.doi.org/10.1116/1.4721649

Reduced leakage currents and possible charge carriers tuning in Mg-doped Ga0.6Fe1.4O3 thin films

Ga0.6Fe1.4O3 is predicted to be magnetoelectric with non zero magnetization at room temperature. However, in thin films, electric properties are overshadowed by strong leakage currents. In this Letter, we show that Mg doping in Ga0.6Fe1.4O3 thin films grown by pulsed laser deposition allows decreasing the leakage current density by four orders of magnitude and might simultaneously allow tuning the carriers' nature. These results suggest the possibility to develop a new class of material exhibiting room temperature magnetization, tunable transport properties, and magnetoelectric properties. (C) 2012 American Institute of Physics.This work was supported by the CNRS PICS program #5733 and the Leading Foreign Research Institute Recruitment Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (MEST) (2011-00267)

Atomic Resolution Cryo-EM Structure Of A Nativelike CENP-A Nucleosome Aided By An Antibody Fragment

Genomic DNA in eukaryotes is organized into chromatin through association with core histones to form nucleosomes, each distinguished by their DNA sequences and histone variants. Here, we used a single-chain antibody fragment (scFv) derived from the anti-nucleosome antibody mAb PL2-6 to stabilize human CENP-A nucleosome containing a native α-satellite DNA and solved its structure by the cryo-electron microscopy (cryo-EM) to 2.6 Å resolution. In comparison, the corresponding cryo-EM structure of the free CENP-A nucleosome could only reach 3.4 Å resolution. We find that scFv binds to a conserved acidic patch on the histone H2A-H2B dimer without perturbing the nucleosome structure. Our results provide an atomic resolution cryo-EM structure of a nucleosome and insight into the structure and function of the CENP-A nucleosome. The scFv approach is applicable to the structural determination of other native-like nucleosomes with distinct DNA sequences

Highlights of the DNA cutters:a short history of the restriction enzymes

In the early 1950’s, ‘host-controlled variation in bacterial viruses’ was reported as a non-hereditary phenomenon: one cycle of viral growth on certain bacterial hosts affected the ability of progeny virus to grow on other hosts by either restricting or enlarging their host range. Unlike mutation, this change was reversible, and one cycle of growth in the previous host returned the virus to its original form. These simple observations heralded the discovery of the endonuclease and methyltransferase activities of what are now termed Type I, II, III and IV DNA restriction-modification systems. The Type II restriction enzymes (e.g. EcoRI) gave rise to recombinant DNA technology that has transformed molecular biology and medicine. This review traces the discovery of restriction enzymes and their continuing impact on molecular biology and medicine

Low temperature sintering of the binary complex perovskite oxides xBa(Zn1/3Ta2/3)O3+(1−x)Ba(Mg1/3Ta2/3)O3

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Low temperature sintering of B2O3/LiNO3 added BaMg1/3Ta2/3O3 ceramics

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