Dimensionality Effect in Quasi-One-Dimensional Mott Insulators

We examine the effect of interchain hopping on the quasi-one-dimensional Hubbard model at half filling. Treating interactions within the weak-coupling perturbation theory, we derive two-loop renormalization-group equations for vertices and self energies. It is shown that the Mott gap is suppressed for weak interchain hopping, while it is enhanced for strong interchain hopping.     

Enhanced charge localization in the organic alloys [(TMTSF)1 − x(TMTTF)x]2ReO4

We present a study of the organic alloys [(TMTSF)_{1 − x}(TMTTF)_x]₂ReO₄. They exhibit an enhanced charge localization and a strong decrease of the (,,) anion ordering (AO) transition temperature. Contrary to the (TMTDTSF)₂ReO₄ salt, this behavior does not interpolate that of the x = 0 and x = 1 pure compounds. It is ascribed to the presence of a 4k_F site charge density wave due to the alternate order of the organic molecules, which weakened the 2k_F bond response function of the one-dimensional electron gas.     

(TM)2X organic superconductors: Interplay between 1-D charge localization and higher dimensionality cross-over

A survey of transport and magnetic properties of the (TM)₂X series together with a recent investigation in high magnetic fields shows that the charge localization occurring at low temperature in a 1-D half-filled band is suppressed by the 1-D to 2-D (3-D) cross-over in selenium compounds. However, a localization around 30 K in the non-ordered phase can be reactivated by the application of a high transverse magnetic field. The intermediate (strong) coupling limit is valid for the spin degree of freedom whereas the charge is governed by the strength of the Umklapp scattering varying by a large factor from sulfur to selenium compounds and under pressure.     

Overexpression of MID2 suppresses the profilin-deficient phenotype of yeast cells

Profilin-deficient Saccharomyces cerevisiae cells show abnormal growth, actin localization, chitin deposition, bud formation and cytokinesis. Previous studies have also revealed a synthetic lethality between pfy1 and late secretory mutants, suggesting a role for profilin in intracellular transport. In this work, we document further the secretion defect associated with the pfy1delta mutant. Electron microscopic observations reveal an accumulation of glycoproteins in the bud and in the mother cell. The MATa, pfy1delta cells mate as well as wild-type cells, while the mating efficiency of MAT alpha, pfy1delta cells is reduced. Pulse-chase experiments demonstrate an accumulation of the 19 kDa alpha-factor precursor and delayed secretion of the mature alpha-factor. The TGN protein Kex2p is the principal enzyme responsible for the endoproteolytic cleavage of the alpha-factor precursor. An immunofluorescence detection of Kex2p shows an altered localization in pfy1delta cells. Instead of a discrete punctate distribution, the enzyme is dispersed throughout the cytoplasm. A high-copy-number plasmid containing MID2, which encodes a potential transmembrane protein involved in cell cycle control, suppresses the abnormal growth, actin distribution, alpha-factor maturation and the accumulation of intracellular membranous structures in pfy1delta cells.     

Job strain and evolution of mental health among nurses.

The objective of this 2nd phase of a 2-year study among female nurses was to provide further empirical validation of the demands-control and social support model. The association of job strain with psychological problems and the potential modifying role of social support at work were examined. A questionnaire was sent at the workplace to 1,741 nurses. The same associations were found between psychological demands, decision latitude, and a combination of the 2 with psychological distress and emotional exhaustion for current exposure and for cumulative exposure. Social support had a direct effect on these psychological symptoms but did not modify their association with job strain. Longitudinal and prospective data are needed to study the occurrence and persistence of health problems when exposure is maintained or retrieved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Determination of the active-layer temperature near the channel of GaAs MESFET''s

A technique is proposed by which the self-heating in the channel of a GaAs field-effect transistor (FET) can be determined using the temperature dependent shift of the optical absorption edge. This shift can be observed by measuring either the wavelength dependent photovoltage at the gate or the photoconduction at the drain terminal of the transistor. The electric field dependent shift was found to be negligible. An empirical equation was used to fit the experimental data for six different transistors. This result was then used to calculate the channel temperature.