Studies on the metal-nuclotide (Co-5′IMP,Co-5′GMP) interaction via mössbauer emission spectroscopy and magnetic susceptibility measurements

By means of⁵⁷Co Mössbauer emission spectroscopy and magnetic susceptibility measurements, the local symmetries and electronic structure of the Co(II) ions in the Co-5IMO and Co-5GMP complexes in the hydrated and dehydrated forms have been determined.     

Investigating 3He diffusion NMR in the lungs using finite difference simulations and in vivo PGSE experiments

Finite difference simulations have been used to model (3)He gas diffusion in simulated lung tissue. The technique has the advantage that a wide range of structural models and diffusion-sensitizing gradient waveforms can be investigated, for which analytical methods would otherwise be virtually impossible. Results from simulations and in vivo pulsed-gradient-spin-echo (PGSE) experiments show that the apparent diffusion coefficient (ADC) is a function of diffusion time and gradient strength, and suggests diffusion is locally anisotropic. The simulations have been compared to recent work on an analytical model that characterizes lung tissue as a series of independent cylinders. The results presented may have clinical implications for (3)He ADC measurements in assessing lung diseases such as chronic-obstructive-pulmonary-disease.     

Synthesis of VO2 (B) nanorods for Li battery application

Vanadium dioxide nanorods were synthesized through a hydrothermal reaction from V₂O₅ xerogel, poly(vinyl pyrrolidone) (PVP) and lithium perchlorate (LiClO₄). The prepared samples were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical discharge–charge cycling in lithium battery. SEM images reveal the nanorods to have dimensions on the order of 1–3 μm in length and 10–50 nm in diameter. The measured initial discharge capacity of the lithium battery with a cathode made of VO₂ (B) nanorods was 152 mA h/g.     

Effective potentials in the Lifshitz scalar field theory

We study the one-loop effective potentials of the four-dimensional Lifshitz scalar field theory with the particular anisotropic scaling z=2, and the mass and the coupling constants renormalization are performed whereas the finite counterterm is just needed for the highest order of the coupling because of the mild UV divergence. Finally, we investigate whether the critical temperature for the symmetry breaking can exist or not in this approximation.     

Extreme-value dependence: An application to exchange rate markets

Extreme value theory (EVT) focuses on modeling the tail behavior of a loss distribution using only extreme values rather than the whole data set. For a sample of 10 countries with dirty/free float regimes, we investigate whether paired currencies exhibit a pattern of asymptotic dependence. That is, whether an extremely large appreciation or depreciation in the nominal exchange rate of one country might transmit to another. In general, after controlling for volatility clustering and inertia in returns, we do not find evidence of extreme-value dependence between paired exchange rates. However, for asymptotic-independent paired returns, we find that tail dependency of exchange rates is stronger under large appreciations than under large depreciations.     

The adsorption of oxygen on Cu(210)

The system Cu(210)-O₂ has been examined using LEED and AES, combined with optical simulation of diffraction patterns to investigate the detailed structure of the adsorbed layer. Exposure at 300 K and 5 × 10^?9 Torr resulted in LEED patterns showing pronounced streaks. The corresponding structures are believed to require an adsorption mechanism in which O₂ dissociation can occur only at a limited number of surface sites and in which O atoms after dissociation diffuse over quite large distances (?10 nm) before becoming chemisorbed. Heating these structures to 500–600 K produced a sharp (2 × 1) pattern; this step is thought to involve equilibration of the adsorbed layer. Further combinations of exposure (?1 × 10^?6Torr) and heating (up to 500 K) resulted in a series of (2 × 1) and (3 × 1) patterns, while heating to 800 K at any stage of the oxygen interaction regenerated the clean surface.