Hydrogen evolution from cathodically charged titanium aluminide alloy Ti–24Al–11Nb

A Ti₃Al-based titanium aluminide alloy, Ti–24Al–11Nb, was cathodically charged with hydrogen in a 5% H₂SO₄ aqueous solution for various charging times, and the formation and dissociation of the hydride, the hydrogen evolution behavior and the total hydrogen uptake were investigated mainly by means of X-ray diffractometry and thermal desorption spectroscopy (TDS). The same kind of hydride phase as observed previously in Ti–25Al alloy (hexagonal hydride) was presumably formed in the Ti–24Al–11Nb alloy after cathodic charging. No damage, such as cracks, was induced by hydrogen charging. Two kinds of TDS peaks, one probably corresponding to hydride dissociation and the other to hydrogen dissolution in the normal lattice site, were found after longer hydrogen charging. It is suggested that niobium addition to Ti₃Al-based titanium aluminide alloy may reduce hydrogen susceptibility during cathodic charging.     

Development of a calculation system for the estimation of decontamination effects

A calculation system for the estimation of decontamination effects (CDE) is developed in the present work to aid in the effective planning of decontamination procedures. This system calculates dose rate distribution before and after decontamination according to the distribution of radioactivity and the decontamination factor. A dose rate reduction factor is also used to estimate decontamination effects. Results obtained from CDE were compared with measurements and particle and heavy-ion transport code system (PHITS) simulations. The CDE successfully reproduced the measured and calculated dose rate distributions, requiring less than several seconds of calculation time.     

Experimental analyses of bismuth sample reactivity worth at Kyoto University Critical Assembly

Sample reactivity worth experiments are carried out by substituting aluminum (Al) plates for bismuth (Bi) ones at the Kyoto University Critical Assembly. At the beginning, uncertainty quantification of bismuth isotope is conducted by deterministic calculations with nuclear data library JENDL-4.0, with the use of experimental results of sample reactivity worth. Then, with the combined use of current (Bi) and previous (Pb) experimental results that demonstrate the comparative difference in the sensitivity and uncertainty of Bi and Pb isotopes, experimental results of cross-section uncertainties of Bi isotope are available for examination of neutron characteristics of Pb–Bi coolant material in the accelerator-driven system. From the experimental analyses, further uncertainty analyses by neutron transport calculations are needed for several reactions of Bi isotope, especially with the use of the covariance data of capture, elastic scattering and inelastic scattering reactions in another nuclear data library.     

Free Fatty Acid Derivative HUHS2002 Potentiates α7 ACh Receptor Responses Through Indirect Activation of CaMKII

The present study examined the effect of 4-[4-(Z)-hept-1-enyl-phenoxy] butyric acid (HUHS2002), a free fatty acid derivative, on α7 acetylcholine (ACh) receptor responses. HUHS2002 potentiated whole-cell membrane currents through α7 ACh receptors expressed in Xenopus oocytes in a concentration (1–100 nM)-dependent manner, reaching about 140 % of the original amplitude at 100 nM 50 min after a 10-min treatment. The HUHS2002 effect was prevented by KN-93, an inhibitor of Ca²⁺/calmodulin-dependent protein kinase II (CaMKII), while it was not affected by GF109203X, an inhibitor of protein kinase C (PKC), or H-89, an inhibitor of protein kinase A (PKA). In the in situ CaMKII assay using cultured rat hippocampal neurons, HUHS2002 activated CaMKII and the activation was abolished by KN-93. In the cell-free assay of protein phosphatase 1 (PP1), HUHS2002 partially inhibited PP1 activity. Taken together, these results indicate that HUHS2002 potentiates α7 ACh receptor responses by indirectly activating CaMKII, possibly via inhibition of PP1.     

An investigation of the reasons for non-compliance with FAR regulations in Tehran

The majority of the Tehran metropolitan region’s problems are associated with building contraventions, which intensified after migration from other parts of the country to the region increased. This migration coincided with a boom in the construction sector and an increase in density selling by the Tehran municipality.     

Reduction of oxide layer on various metal surfaces by atomic hydrogen treatment

The reduction of various metallic oxides was examined. Atomic hydrogen generated on a heated tungsten catalyzer was used for reduction. It was found that Cu, Ru, Nb, Mo, Rh, Pd, Ir and Pt oxides can be reduced by irradiation with atomic hydrogen. The activation energy for oxide removal was examined and it was found that the values were very small, 10^− 2 to 10^− 4 eV.     

Domain Wall Displacement is the Origin of Superior Permittivity and Piezoelectricity in BaTiO3 at Intermediate Grain Sizes

The dielectric and piezoelectric properties of ferroelectric polycrystalline materials have long been known to be strong functions of grain size and extrinsic effects such as domain wall motion. In BaTiO₃, for example, it has been observed for several decades that the piezoelectric and dielectric properties are maximized at intermediate grain sizes (≈1 μm) and different theoretical models have been introduced to describe the physical origin of this effect. Here, using in situ, high‐energy X‐ray diffraction during application of electric fields, it is shown that 90° domain wall motion during both strong (above coercive) and weak (below coercive) electric fields is greatest at these intermediate grain sizes, correlating with the enhanced permittivity and piezoelectric properties observed in BaTiO₃. This result validates the long‐standing theory in attributing the size effects in polycrystalline BaTiO₃ to domain wall displacement. It is now empirically established that a doubling or more in the piezoelectric and dielectric properties of polycrystalline ferroelectric materials can be achieved through domain wall displacement effects; such mechanisms are suggested for use in the design of new ferroelectric materials with enhanced properties.     

Prognostic significance of febrile episodes in lung cancer patients receiving chemotherapy

AIM: To evaluate the prevalence of iron overload in chronic hepatitis C and its relationship with liver histology. PATIENTS AND METHODS: Serum iron, unsaturated iron binding capacity and ferritin levels were determined in 204 consecutive anti-hepatitis C virus positive subjects, whereas hepatic iron concentration, hepatic histological grading and staging, hepatitis C virus genotypes were further assessed in a subgroup of 50 patients who underwent liver biopsy for chronic hepatitis. RESULTS: An increase in the serum markers of iron metabolism was more frequently found in subjects with aminotransferase activities above the normal range, whereas hepatic iron overload, established by direct hepatic iron determination, was found only in 9/50 (18%) patients with chronic hepatitis C. No serum iron marker could reliably predict hepatic iron stores. Patients with mild iron overload usually showed active hepatitis and fibrosis, whereas iron overload was not present in patients without fibrosis or with very mild fibrosis. Two out of nine patients with iron overload were shown to be beta thalassaemia heterozygous, and two were heterozygous carriers of a putative haemochromatosis gene mutation (His63Asp). CONCLUSIONS: Many anti-hepatitis C virus positive patients with elevated aminotransferase activities have serum ferritin levels above the normal range, but only a minority of patients with chronic hepatitis C have a mild iron overload. In chronic hepatitis C, a relationship does exist between hepatic iron content and liver fibrosis.     

Tight-binding parametrization of transition metal elements from LCAO ab initio Hamiltonians

We have performed ab initio calculations of Cu clusters using the DVM method [1]. The knowledge of the Hamiltonian matrix allows us to construct a tight-binding parameter set which reproduces the same eigenvalues. Furthermore, from the ab initio total energies, we construct an additional short-range repulsive interaction, which added to the tight-binding eigenvalues, yields the total energy. We have thus a tight-binding parametrization that allows us to perform molecular dynamics simulations of Cu clusters. We hope to use the same technique to get the tight-binding parameters of other magnetic and nonmagnetic transition metal atoms.