Search results for "DEPENDENCE"

P50 sensory gating and smoking in the general population

2011

P50 gating is a major functional biomarker in research on schizophrenia and other psychiatric conditions with high smoking prevalence. It is used as endophenotype for studying nicotinic systems genetics and as surrogate endpoint measure for drug development of nicotinic agonists. Surprisingly, little is known about P50 gating in the general population and the relationship to smoking-related characteristics. In this multicenter study at six academic institutions throughout Germany, n = 907 never-smokers (NS < 20 cigarettes/lifetime), n = 463 light smokers (LS) with Fagerstrom Test for Nicotine Dependence (FTND) ≥ 4 and n = 353 heavy smokers (HS, FTND < 4) were randomly selected from the gene…

Association of ADH4 genetic variants with alcohol dependence risk and related phenotypes: results from a larger multicenter association study

2011

Genetic variants of the alcohol-metabolizing enzyme ADH4, located on chromosome 4q22-4q23, have been related to alcohol dependence (AD) risk in previous research. The aim of this association study in a large multicenter sample of alcohol-dependent individuals and controls is to confirm ADH4 single nucleotide polymorphism (SNP) and haplotype association with AD and relevant related phenotypes. One thousand, six hundred and twenty-two (1622) inpatient subjects and 1469 control subjects with DSM-IV. AD from four addiction treatment centres were included. Characteristics of AD and related phenotypes including alcohol withdrawal, Cloninger's type I and II and first ages of drinking, regular drin…

Effects on arterial blood pressure of the methanol extracts from differentTeucriumspecies

1997

Methanol extracts of the leaves and stems of two Teucrium species (T. pumillum L. and T. buxifolium L.) have been tested for their effects on resting arterial blood pressure. Both T. pumillum L. and T. buxifolium L. extracts reduced mean arterial blood pressure in a dose dependent manner when administered i.v. to urethane anaesthetized normotensive rats. © 1997 John Wiley & Sons, Ltd.

Pressure Dependence of the Low-Frequency Dielectric Constant in III-VI Semiconductors

1999

In this work we report on the pressure dependence of the low-frequency dielectric constant parallel to the c-axis (e∥) in GaS, GaSe, and InSe as obtained from direct capacitance measurements. A large increase of e∥ with pressure has been observed. The pressure change of the lattice polarizability along the c-axis is calculated in the framework of a rigid-ion model from the change of the angle of the anion–cation bond with respect to the layer plane, which results in a slight increase of the lattice contribution. Consequently, the pressure behaviour of e∥ is proposed to arise from the large increase of the electronic polarizability along the c-axis. This is explained through a decrease of th…

Phase transitions in modified Na 1/2 Bi 1/2 TiO 3 ‐SrTiO 3 solid solutions

2009

Continuous transfer from relaxor to normal ferroelectric phase transition is found in Na1/2Bi1/2TiO3-SrTiO3-PbTiO3 if concentration of PbTiO3 increases. The relaxor properties in NBT solid solutions are described by the power law and Vogel-Fulcher relationship, and concentration dependence of the relevant parameters is discussed. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Phase Transitions in Na1/2Bi1/2TiO3-SrTiO3-PbTiO3Solid Solutions

2010

All sequential steps of transfer from relaxor to normal ferroelectric phase transition are found in Na1/2Bi1/2TiO3-SrTiO3-PbTiO3 if concentration of PbTiO3 increases. The relaxor properties in Na1/2Bi1/2TiO3-SrTiO3-PbTiO3 solid solutions are described by the power law and Vogel-Fulcher relationship. Concentration dependence of the relevant parameters is discussed. Stability of relaxor and ferroelectric phases is discussed by analyzing behaviour of critical electric fields.

Density-functional study of pressure-induced phase transitions and electronic properties of Zn2V2O7

2021

We report a study of the high-pressure behavior of the structural and electronic properties of Zn2V2O7 by means of first-principle calculations using the CRYSTAL code. Three different approaches have been used, finding that the Becke–Lee–Yang–Parr functional is the one that best describes Zn2V2O7. The reported calculations contribute to the understanding of previous published experiments. They support the existence of three phase transitions for pressures smaller than 6 GPa. The crystal structure of the different high-pressure phases is reported. We have also made a systematic study of the electronic band-structure, determining the band-gap and its pressure dependence for the different poly…

Comment on “Molybdenum sound velocity and shear modulus softening under shock compression”

2015

In this Comment we discuss recent results presented by Nguyen et al. on shock compressed molybdenum up to 438 GPa [Phys. Rev. B 89, 174109 (2014)]. The aim of Nguyen's article is to show that there is no phase transition near 210 GPa. We propose instead an interpretation of their data that this material shows the onset of partial melting along the Hugoniot at $240(20)\phantom{\rule{0.28em}{0ex}}\mathrm{GPa}$, which is evident from abrupt changes in the pressure dependence of the shear modulus. This interpretation may solve the significant controversy in the melting slopes derived from shock and static experiments.

IS MEANING WITHOUT ACTUALLY EXISTING REFERENCE NATURALIZABLE?

1995

Luminescence Efficiency of Si/SiO 2 Nanoparticles Produced by Laser Ablation

2019

Photoluminescence properties of Si(core)/SiO 2 (shell) nanoparticles produced by pulsed laser ablation in aqueous solution are investigated with the purpose to highlight the microscopic processes that govern the emission brightness and stability. Time resolved spectra evidence that these systems emit a µs decaying band centered around 1.95 eV, that is associated with the radiative recombination of quantum-confined excitons generated in the Si nanocrystalline core. Both the quantum efficiency and the stability of this emission are strongly dependent on the pH level of the solution, that is changed after the laser ablation is performed. They enhance in acid environment because of the H + pass…