Method for Assessing the Sustainability of the Information Direction, Functioning on the Resources of the Communication Network with Failures

The article presents the main directions of the qualitative and quantitative assessment of sustainability in the field of infocommunications, shows the differences in approaches to the definition of sustainability. A method is proposed that differs from the known well-grounded application of the provisions of the theory of random impulse flows. The generalized impulse flow describes the robustness of data transmission in the information direction. The estimation method allows one to take into account both the states of the elements of a composite channel, represented by impulse flows of failures and restorations, and transient processes and sub-processes of information exchange (transmission over a communication line, switching, storage in memory, destructive influences, etc.), represented by separate impulse streams. The variability of the composition of the impulse streams makes it possible to increase the accuracy and reliability of the assessment.

Where and how does d-amphetamine act to reveal antipsychotic-induced dopamine supersensitivity in rats?

ABSTRACTAntipsychotic treatment can produce a dopamine supersensitive state. In both schizophrenia patients and rodents, this is linked to antipsychotic treatment failure. In rodents, dopamine supersensitivity is often confirmed by an exaggerated behavioural response to the indirect monoamine agonist, d-amphetamine, after discontinuation of antipsychotic treatment. Here we investigated where and how d-amphetamine acts to trigger behavioural expression of dopamine supersensitivity, as this could uncover pathophysiological mechanisms underlying this supersensitivity. First, we examined the contributions of a central increase in dopamine/monoamine activity. Haloperidol-treated rats showed a potentiated psychomotor response to systemic d-amphetamine, confirming dopamine supersensitivity. However, they showed a normal psychomotor response to an increase in ventral midbrain dopamine impulse flow or to intracerebroventricular injection of d-amphetamine. This suggests that d-amphetamine’s peripheral effects are required for a supersensitive response. Second, we determined the specific contributions of dopamine neurotransmission. The D2 agonist quinpirole, but not the D1 agonist SKF38393 or the dopamine reuptake blocker GBR12783 produced a supersensitive psychomotor response in haloperidol-treated rats. In these rats, the D1 antagonist SCH39166 decreased d-amphetamine-induced psychomotor activity, whereas the D2 antagonist sulpiride enhanced it. Thus, when d-amphetamine triggers a supersensitive response, this involves both D1- and D2-mediated transmission. Finally, we measured d-amphetamine-induced changes in D1- and D2-mediated intracellular signalling pathways in the striatum. In haloperidol-treated rats, a supersensitive response to d-amphetamine was linked to enhanced GSK3β activity and suppressed ERK1/2 activity in the nucleus accumbens, suggesting increased D2-mediated signalling. These findings provide new insights into the neurobiology of antipsychotic-evoked dopamine supersensitivity.

The influence of the numerical solver selection on the nozzle impulse flow simulation results

Numerical simulations are currently used for different applications in a various fields of science. Certain solutions are not as obvious as the others while the results can give very valuable conclusions. Computational Fluid Dynamics (CFD) is one of the tools that can be used to solve different problems related with the mass and heat transfer. Nowadays it is already known that the impulse flow simulation allows to determine pressure pulsation attenuation parameters by a given geometry. However, the nozzle shape optimization method strongly depends on the numerical results obtained from the impulse flow simulation. In commercial CFD software Ansys-Fluent the obtained results depends strongly on the chosen numerical methods, especially the spatial discretization method. This is the reason to use other software as a benchmark. Alternative software FlowVision was used to perform the impulse flow simulation for the same geometries to compare the results. As there is a different problem definition in both systems the calculations, accuracy and results differ from each other. The paper describes the numerical differences between solvers. Article contains discussion about obtained results and includes hints how to avoid mistakes when user change software, especially in solving unusual CFD problems.

Burst activation of dopamine neurons produces prolonged post-burst availability of actively released dopamine

SummaryBoth phasic and tonic modes of neurotransmission are implicated in critical functions assigned to dopamine. In learning, for example, sub-second phasic responses of ventral tegmental area (VTA) dopamine neurons to salient events serve as teaching signals, but learning is also interrupted by dopamine antagonists administered minutes after training. Our findings bridge the multiple timescales of dopamine neurotransmission by demonstrating that burst stimulation of VTA dopamine neurons produces a prolonged post-burst increase (> 20 min) of extracellular dopamine in nucleus accumbens and prefrontal cortex. This elevation is not due to spillover from the stimulation surge but depends on impulse flow-mediated dopamine release. We identified Rho-mediated internalization of dopamine transporter as a mechanism responsible for prolonged availability of actively released dopamine. These results demonstrate that phasic and tonic dopamine neurotransmission can be a continuum and may explain why both modes of signaling are critical for motivational and cognitive functions associated with dopamine.