Light- and electric-field-induced first-order orientation transitions in a dendrimer-doped nematic liquid crystal.

Interaction of light and ac electric fields with a nematic liquid crystal (NLC) doped with nanosized second-generation carbosilane codendrimers containing terminal azobenzene fragments has been studied. A first-order Freedericksz transition in the linearly polarized light, accompanied by an intrinsic bistability in a wide region, was observed. An additional ac electric field decreases the light-induced Freedericksz transition threshold and narrows the bistability region.

Lead in residential soil and dust in a mining and smelting district in northern Armenia: a pilot study.

This pilot study of sources of lead exposure in residential settings was conducted in a mining and smelting district in northern Armenia. Samples of exterior soil and dust and interior house dust were collected in and around apartment buildings in Alaverdi where the country's largest polymetallic smelter is located, and in nearby mining towns of Aghtala and Shamlugh. The NITON XL-723 Multi-Element XRF analyzer was used for lead testing.

Mediator mechanisms of cathinone effects on animal behaviour.

The effect of cathinone on the visual differentiation of cats was investigated by the method of defense conditioned reflexes. It was found that cathinone decreases the differentiation of both the short-term and prolonged visual stimuli. These effects of cathinone increase when the serotoninergic system is activated and decrease under dopaminergic system activation.