A Simple Model for Hydrogen-Bonding Ferroelectrics

There are some substances in which their hydrogen bonds are considered to play quite important roles in their ferroelectric or antiferroelectric phase transition. These ferroelectrics usually have large isotope effects in phase transition temperatures and we expect the physics of hydrogen bonds is closely related to the effects. We propose a simple model describing the isolated hydrogen bond. Based on quantum-mechanical analyses of this model, we study the difference between the behavior of a proton and a deuteron in hydrogen bonds

Numerical Analysis of a Model for Isolated Hydrogen Bond

Large isotope effects have been observed in various kinds of hydrogen bonded ferro / antiferroelectrics. In clariflying their origin, themodynamic properties of the hydrogen bond are of essential importance. Two numerical methods are applied to analyze the model for isolated hydrogen bond at finite temperatures and the results of excited energy levels of proton or deuteron are examined. It is found that the second excited state is not far enough from the first excited state to be neglected discussing themodynamic properties of hydrogen especially in their ordered states

Note on the Piezoelectric Constant of PbZrO(3)-PbTiO(3)(PZT)

One of the best known solid solution of perovskites is the PbTiO(3)-PbZrO(3) system which is usually abbreviated as PZT. In the phase diagram of this system, there is a drastic phase change from tetragonal to rhombohedral at the molar ratio around 50:50. The PZT crystals are widely used as a practical piezoelectric material because of its very strong piezoelectric effect near this morphotropic phase boundary. We try to explain this anomaly in piezoelectric constant by a phenomenological theory

Study on the Floatability of Mineral Particles in the Presence of Surface Active Agents I : Relation between Adsorption of the Collector Ion and the Electrokinetic Potential in Flotation

The electro-osmotic velocity, the adsorption density and the floatability of mineral particles were measured for the following systems : fluorite-sodium dodecyl benzene sulphonate, quartz-sodium dodecyl benzene sulphonate, quartz-octadecyl dimethyl benzyl ammonium chloride, scheelite-octadecyl dimethyl benzyl ammonium chloride and quartz-dodecyl ammonium acetate. The relations among the differences in the zeta-potential, the adsorption density and the floatability are discussed. As a result of this research, it was found that the difference in the zeta-potential of the mineral can be correlated with the adsorption density of the collector on the mineral surface, and that, therefore, the floatability of the mineral can be correlated with the difference in the zeta-potential

Rastreamento bacteriano nos pontos críticos de contaminação por coliformes e Escherichia coli em indústria de laticínios na região norte do estado do Paraná

Orientador : Ronaldo TamaniniMonografia (especialização) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Curso de Especialização em Gestão Agropecuária com ênfase em Inspeção de produtos de origem animalInclui referência

The Electronic Structure of C(60) Molecule -Structure of π-electron Band-

The π-electron band of C(60) molecule has been obtained by the tight binding approximation. Application of molecular orbital wave functions derived on the basis of the optimized bond orbital model gives, with simpler calculations, the results in satisfactory agreement with those of previous theoretical analyses

Sperionic Conductors and Anharmonic Lattice Vibration

Important role played by anharmonic lattice vibration in superionic conductors is pointed out. As an example, anisotropic and large anharmonic vibration of Cu ion in α-CuI crystal is discussed. A mechanism of the sublattice melting is proposed in which cooperative interaction between Cu and I ions leads to an instability in Cu sublattice

Note on Structure Parameters of Wurtzite Type Compounds

Crystal parameters of wurtzite type crystals have been investigated based on the optimized bond orbital model which is known to give the crystal structures of some III-VI compounds as the minimum of bonding energy when bond lengths are fixed. In the case of wurtzite type structures, however, it has become clear that the effect of the change in bond lengths has to be taken into account when minimizing bonding energies

Copy number loss of (src homology 2 domain containing)-transforming protein 2 (SHC2) gene: discordant loss in monozygotic twins and frequent loss in patients with multiple system atrophy

<p>Abstract</p> <p>Background</p> <p>Multiple system atrophy (MSA) is a sporadic disease. Its pathogenesis may involve multiple genetic and nongenetic factors, but its etiology remains largely unknown. We hypothesized that the genome of a patient with MSA would demonstrate copy number variations (CNVs) in the genes or genomic regions of interest. To identify genomic alterations increasing the risk for MSA, we examined a pair of monozygotic (MZ) twins discordant for the MSA phenotype and 32 patients with MSA.</p> <p>Results</p> <p>By whole-genome CNV analysis using a combination of CNV beadchip and comparative genomic hybridization (CGH)-based CNV microarrays followed by region-targeting, high-density, custom-made oligonucleotide tiling microarray analysis, we identified disease-specific copy number loss of the (Src homology 2 domain containing)-transforming protein 2 (<it>SHC2</it>) gene in the distal 350-kb subtelomeric region of 19p13.3 in the affected MZ twin and 10 of the 31 patients with MSA but not in 2 independent control populations (<it>p </it>= 1.04 × 10^-8, odds ratio = 89.8, Pearson's chi-square test).</p> <p>Conclusions</p> <p>Copy number loss of <it>SHC2 </it>strongly indicates a causal link to MSA. CNV analysis of phenotypically discordant MZ twins is a powerful tool for identifying disease-predisposing loci. Our results would enable the identification of novel diagnostic measure, therapeutic targets and better understanding of the etiology of MSA.</p