Posistor blocks of protection of automatic telephone exchanges

The thermal and electrical parameters of posistor blocks or protection of automatic telephone exchanges have been investigated. A mathematical model making it possible to optimize the posistor parameters for designing protective blocks with required characteristics has been proposed. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 5, pp. 88–93, September–October, 2006.     

The effect of the initial (controlled) tonus of the arterial vessels on the correlation of arterial pressure and cardiac output during a pressor reaction to a rapid blood volume increase in rats]

A considerable decrease in pressor responses to polyglykine at an elevated arterial tone and constant increase of cardiac output occurred in anesthetised rats. Vascular and cardiac mechanisms of the interrelationship are discussed.     

A comparative study of the interaction of phosphoric acid dichlorovinyl esters with a neurotoxic esterase from the brain of hens and rats

In order to validate a rodent biochemical model of delayed neurotoxicity of organophosphates (OP) inhibition of rat and hen brain neurotoxic esterase (NTE) by some dichlorovinyl phosphates and phosphonates was studied in vitro and in vivo. It was shown that compounds investigated exhibited the similar inhibitory potency to NTE from both species in vitro, in addition rat and hen NTE showed the same sensitivity to variation of the structure of OP inhibitors. A good correlation was found between pI50 estimated with enzymes from rat and hen trains: r2 = 0.951, n = 18, p < or = 0.05. NTE activities were also measured in rat and hen brains after acute administration of various dosages of potent axonopathic compound dipropyldichlorovinyl phosphate. The results obtained indicate that difference in species susceptibility to neurotoxic action of OP, in particular the absence of ataxia in rats, is not caused by difference in target enzyme sensitivity to axonopathic organophosphates.     

Response of the receptive fields of the lateral geniculate body to temporal changes in the area of a light stimulus

Neuronal responses of the cat LGB to light spots the area of which was changing in time with different speed, were studied. All the neurons responding to switching on and off of the test spot respond to changing in time of the spot area too. The on-neurons respond to enlargening of the area while the off-neurons - to its reducing. The on- and off-responses of these fields occurred at the moment of passing of the margin of reducing (growing) spot across a certain point of neuron's receptive field. This point changed when the speed of reducing (growing) of the test spot changed.