Liquid-vapor coexistence curves and critical parameters for hard-core 1:1 electrolyte models with diameter ratios lambda = sigma(-)/sigma(+) = 1 to 5.7 have been studied by fine-discretization Monte Carlo methods. Normalizing via the length scale sigma(+/-) = 1 / 2(sigma(+)+sigma(-)), relevant for the low densities in question, both T(*)(c) ( = k(B)T(c)sigma(+/-)/q(2)) and rho(*)(c) ( = rho(c)s...

Extracytoplasmic function (ECF) sigma factors constitute a diverse family of proteins, within the class of the sigma 70 subunit of RNA polymerase. Most members of the family studied to date are known to regulate gene expression in response to stress conditions. The Bacillus subtilis genome encodes at least 17 distinct sigma factors, seven of which are members of the ECF subfamily. Among these, ...

Two genes of the sigB operon, rsbU and rsbV, were deleted in an rsbU(+) strain (FDA486) to evaluate the contribution of these two genes to sigma(B) activity in Staphylococcus aureus. The sigma(B) protein level and the transcription of two sigma(B)-dependent promoters (sigB and sarA P3 transcripts) were analyzed in the constructed mutants. A deletion of the first gene (rsbU) within the sigB oper...

Extracytoplasmic function or ECF sigma factors are the most abundant class of alternative sigma factors in bacteria. Members of the rpoE subclass of ECF sigma factors are implicated in sensing stress in the cell envelope of Gram-negative bacteria and are required for virulence in many pathogens. The best-studied member of this family is rpoE from Escherichia coli, encoding the sigma(E) protein....

Sigma (sigma) receptors, initially described as a subtype of opioid receptors, are now considered unique receptors. Pharmacological studies have distinguished two types of sigma receptors, termed sigma(1) and sigma(2). Of these two subtypes, the sigma(1) receptor has been cloned in humans and rodents, and its amino acid sequence shows no homology with other mammalian proteins. Several psychoact...

Sigma-1 receptor antagonists promote antinociception in several models of pain, but the effects of sigma-1 agonists on nociception (particularly when the nociceptive system is primed) are not so well characterized; therefore we evaluated the effects of sigma-1 agonists on pain under different experimental conditions. The systemic administration of the selective sigma-1 agonists (+)-pentazocine ...

We study the distribution P(sigma) of the equivalent conductance sigma for Erdös-Rényi (ER) and scale-free (SF) weighted resistor networks with N nodes. Each link has conductance g triple bond e-ax, where x is a random number taken from a uniform distribution between 0 and 1 and the parameter a represents the strength of the disorder. We provide an iterative fast algorithm to obtain P(sigma) an...

BACKGROUND Sigma-1 receptors are involved in regulation of neuronal activities presumably through regulation of the activity of ion channels. Sigma-1 receptors also play a role in growth and metastasis of cancerous cells. Intracellular distribution of sigma-1 receptors have been linked to sphingolipid-enriched domains. RESULTS We report that in CHO-K1 cells sigma-1 receptors target to focal a...