A Brief (If Insular) History of the Human Genome Project

Michael Morgan reviews Drawing the Map of Life, an American journalist's view of the international sequencing effort

Local electronic structure in MgB2 from 12B β-NMR

We performed β-NMR spectroscopic studies on 12B which was implanted into MgB2 to get insight into the local electronic structure of this high-temperature superconducting material. By measuring electric field gradients we probed the electronic charge distribution anisotropy around boron in this solid and thus obtained experimental information about the bonding by p electrons. Besides the absolute value, the sign of the electric field gradient was also experimentally determined. By comparison with quantum chemical calculations, some of which were performed in the present work, and with results from conventional NMR spectroscopy on 11B we were able to identify regular boron lattice sites as well as interstitial sites. © 2007 The American Physical Society

The Adsorption of H2O on TiO2 and SnO2(110) Studied by First-Principles Calculations

First-principles calculations based on density functional theory and the pseudopotential method have been used to investigate the energetics of H$_2$O adsorption on the (110) surface of TiO$_2$ and SnO$_2$. Full relaxation of all atomic positions is performed on slab systems with periodic boundary conditions, and the cases of full and half coverage are studied. Both molecular and dissociative (H$_2$O $\rightarrow$ OH$^-$ + H$^+$) adsorption are treated, and allowance is made for relaxation of the adsorbed species to unsymmetrical configurations. It is found that for both TiO$_2$ and SnO$_2$ an unsymmetrical dissociated configuration is the most stable. The symmetrical molecularly adsorbed configuration is unstable with respect to lowering of symmetry, and is separated from the fully dissociated configuration by at most a very small energy barrier. The calculated dissociative adsorption energies for TiO$_2$ and SnO$_2$ are in reasonable agreement with the results of thermal desorption experiments. Calculated total and local electronic densities of states for dissociatively and molecularly adsorbed configurations are presented and their relation with experimental UPS spectra is discussed

The translation, validity and reliability of the German version of the Fremantle Back Awareness Questionnaire

Background: The Fremantle Back Awareness Questionnaire (FreBAQ) claims to assess disrupted self-perception of the back. The aim of this study was to develop a German version of the Fre-BAQ (FreBAQ-G) and assess its test-retest reliability, its known-groups validity and its convergent validity with another purported measure of back perception. Methods: The FreBaQ-G was translated following international guidelines for the transcultural adaptation of questionnaires. Thirty-five patients with non-specific CLBP and 48 healthy participants were recruited. Assessor one administered the FreBAQ-G to each patient with CLBP on two separate days to quantify intra-observer reliability. Assessor two administered the FreBaQ-G to each patient on day 1. The scores were compared to those obtained by assessor one on day 1 to assess inter-observer reliability. Known-groups validity was quantified by comparing the FreBAQ-G score between patients and healthy controls. To assess convergent validity, patient\u27s FreBAQ-G scores were correlated to their two-point discrimination (TPD) scores. Results: Intra- and Inter-observer reliability were both moderate with ICC3.1 = 0.88 (95%CI: 0.77 to 0.94) and 0.89 (95%CI: 0.79 to 0.94), respectively. Intra- and inter-observer limits of agreement (LoA) were 6.2 (95%CI: 5.0±8.1) and 6.0 (4.8±7.8), respectively. The adjusted mean difference between patients and controls was 5.4 (95%CI: 3.0 to 7.8, p\u3c0.01). Patient\u27s FreBAQ-G scores were not associated with TPD thresholds (Pearson\u27s r = -0.05, p = 0.79). Conclusions: The FreBAQ-G demonstrated a degree of reliability and known-groups validity. Interpretation of patient level data should be performed with caution because the LoA were substantial. It did not demonstrate convergent validity against TPD. Floor effects of some items of the FreBAQ-G may have influenced the validity and reliability results. The clinimetric properties of the FreBAQ-G require further investigation as a simple measure of disrupted self-perception of the back before firm recommendations on its use can be made

Electronic structure of the MO oxides (M=Mg, Ca, Ti, V) in the GW approximation

The quasiparticle band structures of nonmagnetic monoxides, MO (M=Mg, Ca, Ti, and V), are calculated by the GW approximation. The band gap and the width of occupied oxygen 2p states in insulating MgO and CaO agree with experimental observation. In metallic TiO and VO, conduction bands originated from metal 3d states become narrower. Then the partial densities of transition metal e_g and t_2g states show an enhanced dip between the two. The effects of static screening and dynamical correlation are discussed in detail in comparison with the results of the Hartree-Fock approximation and the static Coulomb hole plus screened exchange approximation. The d-d Coulomb interaction is shown to be very much reduced by on-site and off-site d-electron screening in TiO and VO. The dielectric function and the energy loss spectrum are also presented and discussed in detail.Comment: 10 pages, 5 figure

Metal-insulator and magnetic transition of NiO at high pressures

Published versio

Unravelling ultraslow lithium-ion diffusion in γ-LiAlO2 : experiments with tracers, neutrons, and charge carriers

Lithium aluminum oxide (γ-LiAlO2) has been discussed and used for various applications, e.g., as electrode coating, membrane, or tritium breeder material. Although lithium-ion diffusion in this solid is essential for these purposes, it is still not sufficiently understood on the microscopic scale. Herein, we not only summarize and assess the available studies on diffusion in different crystalline forms of γ-LiAlO2, but also complement them with tracer-diffusion experiments on (001)- and conductivity spectroscopy on (100)-oriented single crystals, yielding activation energies of 1.20(5) and 1.12(1) eV, respectively. Scrutinous crystal-chemical considerations, Voronoi–Dirichlet partitioning, and Hirshfeld surface analysis are employed to identify possible diffusion pathways. The one-particle potential, as derived from high-temperature powder neutron diffraction data presented as well, reveals the major path to be strongly curved and to run between adjacent lithium positions with a migration barrier of 0.72(5) eV. This finding is substantiated by comparison with recently published computational results. For the first time, a complete model for lithium-ion diffusion in γ-LiAlO2, consistent with all available data, is presented.DFG, FOR 1277, Mobilität von Lithiumionen in Festkörpern (molife