[en] Part One, entitled, Potential Inhibitors of Inosine Monophosphate (IMP) Dehydrogenase: Synthesis and Stereochemical Assignments for a Class of C-Nucleosides, concerns the synthesis, stereochemical assignments, and biological evaluation of a pair of α, β-D-arabinofuranosyl analogues of tiazofurin. The target nucleosides were synthesized from 2,3,5-tri-O-benzyl-1-O-(p-nitrobenzoyl)-D-arabinofuranose. Stereochemical assignments in the series were made on the basis of ¹H and ¹³C NMR spectroscopy, two-dimensional (2D FT) NMR, as well as by circular dichroism (CD) spectroscopy. In Part Two, entitled, Substrates of Inhibitors of Enzymes of the Phosphatidylinositol Pathway: Analogues of myo-Inositol, A number of deoxy- and deoxyhalogenocyclitols were synthesized as potential substrates or inhibitors of the primary enzymes of the phosphatidylinositol pathway. Part Three, Synthesis of [2'-¹⁸O]- and [3'-¹⁸O]-Adenosine and Ara-A as Well as an Investigation of Their ¹⁸O-Induced ¹³C NMR Chemical Shifts, involves the synthesis and characterization of the title compounds

[en] The expected radioactive ion production rate for a 200 MeV/u 400 kW driver linac using four different production methods is discussed. For each isotope the optimum method is identified and the rate is calculated based on different model assumptions, empirical observation and extrapolations. The results are compared to the rates expected for a 550 MeV proton driver machine with a beam power of 50 kW, as well as the full RIA facility with a 400 MeV/u 400 kW production linac

[en] Modification of natural graphite has recently moved into the focus of methods to prepare anode materials for lithium ion batteries. Here we report a treatment method for the modification of a common natural graphite employing oxidative solutions. Four solutions based on H₂O₂, Ce(SO₄)₂, HNO₃ and (NH₄)₂S₂O₈ were employed; their effects were investigated with X-ray photoelectron spectroscopy, thermogravimmetric and differential thermal analysis, high resolution electron microscopy and measurement of electrochemical capacity. All oxidants resulted in marked improvements of reversible capacity, columbic efficiency in the first cycle and cycling behavior due to elimination of some imperfections with high activities towards lithium such as carbon chains, edge carbon atoms and sp³-hybridized carbon atoms, creation of more micropores/nano-channels, modification of the surface of natural graphite with a coverage of a dense layer of oxides, and improvement in stability of graphite structure. Effects of the oxidative solutions on electrochemical performance of natural graphite are compared

[en] Using a simplified Eliashberg formulation in which we keep only that part of the susceptibility which is separable and of d_x²-y² symmetry in the pairing channel and keep the isotropic part in the renormalization channel, we have calculated the ac conductivity in the superconducting state. At zero temperature, in the clean limit, we find a finite amount of absorption at any frequency, however small, although it is substantially reduced over its normal-state value. Besides this boson-assisted absorption, when impurities are added a new channel is opened up in which momentum is given up to the impurity system and absorption proceeds directly through the creation of a hole-particle pair. Born and unitary impurity scattering are considered. 12 refs., 2 figs

[en] Using the completed anisotropic Eliashberg equations valid for layered compounds, the authors calculated numerically the temperature-dependent nuclear magnetic resonance rate. The calculations fully include anisotropy, and quasiparticle damping effects represent an extension of previous work in which anisotropy was included approximately through an ansatz. The calculations largely confirm previous work which showed reasonable agreement

[en] The results of a systematic study of the structure and transport properties of the series of compounds La(1-x)Yb(x)BCO (x in the range of 0.05-0.95) are presented. The X-ray patterns revealed that the compounds La(1-x)Yb(x)BCO were single-phase orthorhombically distorted layered perovskites for x less than 0.9. For Yb fractions greater than 90 percent, extra unidentified peaks, whose intensities grew with further increases in x, appeared when 2(theta) was in the range of 29-32 deg. 14 references

[en] Sm₂O₃ was compressed at room temperature up to 44.0 GPa and then decompressed back to ambient pressure. In situ X-ray diffraction was used to monitor the structural changes in the sample. A cubic to hexagonal phase transformation was observed in Sm₂O₃ for the first time. After decompression back to ambient pressure, the hexagonal phase was not quenchable and transformed to a monoclinic phase. Ab initio Density-Functional-Theory (DFT) calculations were performed to obtain theoretical data for comparison with the experimental results and elucidation of the transformation mechanism. A possible phase transformation mechanism that is consistent with the experimental results and theoretical calculations is proposed.

[en] A model where electrons propagate freely in a two-dimensional plane and hop in the third direction perpendicular to the planes is used to study the properties of superconductors with a layered structure. Solving the full anisotropic Eliashberg equations based on our model and using a Fermi Surface Harmonic expansion, we found that anisotropy can have a large influence on critical temperature (Tc), specific heat, temperature dependence of London penetration depth λ_L(T), etc. though its effect becomes less significant as the coupling strength is increased. (orig.)

[en] In an Eliashberg superconductor at zero temperature, there is a clear gap edge as well as phonon structure in the quasiparticle density of states at an energy equal to the gap plus the phonon energy. Here we study how gap and phonon structure shift and get altered with finite temperature and with the introduction of anisotropy when dealing with a layered structure as in the copper oxides. For moderate coupling, gap and phonon structure follow closely the usual BCS temperature variation of the gap, but this no longer holds in very strong coupling where the concept of gap is lost as temperature is increased

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