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"Kozlov, A. S."
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Molecular diversity of spider venom
Spider venom, a factor that has played a decisive role in the evolution of one of the most successful groups of living organisms, is reviewed. Unique molecular diversity of venom components including substances of variable structure (from simple low molecular weight compounds to large multidomain proteins) with different functions is considered. Special attention is given to the structure, properties, and biosynthesis of toxins of polypeptide nature.
Journal Article
Target Cell-Specific Modulation of Neuronal Activity by Astrocytes
Interaction between astrocytes and neurons enriches the behavior of brain circuits. By releasing glutamate and ATP, astrocytes can directly excite neurons and modulate synaptic transmission. In the rat olfactory bulb, we demonstrate that the release of GABA by astrocytes causes long-lasting and synchronous inhibition of mitral and granule cells. In addition, astrocytes release glutamate, leading to a selective activation of granule-cell NMDA receptors. Thus, by releasing excitatory and inhibitory neurotransmitters, astrocytes exert a complex modulatory control on the olfactory network.
Journal Article
Laser Activation of Oxygen in Aerated Solvents. Measurement of the Absorption Spectra of Oxygen Dissolved in Aerated Solvents under Natural Conditions
The results of authors’ studies of the photochemical activity and phosphorescence of oxygen molecules upon direct laser excitation of oxygen in aerated organic solvents and water have been shortly summarized. The absorption spectra of oxygen dissolved in these media at normal pressure and temperature have been obtained in the spectral range of 600–1300 nm. The information received is of fundamental importance for spectroscopy of molecular oxygen and elucidation of the role of oxygen as a photoreceptor triggering the biological action of laser radiation.
Journal Article
Air–Oxygen Blenders for Mechanical Ventilators: A Literature Review
Respiratory diseases are one of the most common causes of death in the world and this recent COVID-19 pandemic is a key example. Problems such as infections, in general, affect many people and depending on the form of transmission they can spread throughout the world and weaken thousands of people. Two examples are severe acute respiratory syndrome and the recent coronavirus disease. These diseases have mild and severe forms, in which patients gravely affected need ventilatory support. The equipment that serves as a basis for operation of the mechanical ventilator is the air–oxygen blender, responsible for carrying out the air–oxygen mixture in the proper proportions ensuring constant supply. New blender models are described in the literature together with applications of control techniques, such as Proportional, Integrative and Derivative (PID); Fuzzy; and Adaptive. The results obtained from the literature show a significant improvement in patient care when using automatic controls instead of manual adjustment, increasing the safety and accuracy of the treatment. This study presents a deep review of the state of the art in air–oxygen benders, identifies the most relevant characteristics, performs a comparison study considering the most relevant available solutions, and identifies open research directions in the topic.
Journal Article
Complex experiment on studying the microphysical, chemical, and optical properties of aerosol particles and estimating the contribution of atmospheric aerosol-to-earth radiation budget
The primary objective of this complex aerosol experiment was the measurement of microphysical, chemical, and optical properties of aerosol particles in the surface air layer and free atmosphere. The measurement data were used to retrieve the whole set of aerosol optical parameters, necessary for radiation calculations. Three measurement cycles were performed within the experiment during 2013: in spring, when the aerosol generation is maximal; in summer (July), when atmospheric boundary layer altitude and, hence, mixing layer altitude are maximal; and in late summer/early autumn, during the period of nucleation of secondary particles. Thus, independently obtained data on the optical, meteorological, and microphysical parameters of the atmosphere allow intercalibration and inter-complement of the data and thereby provide for qualitatively new information which explains the physical nature of the processes that form the vertical structure of the aerosol field.
Journal Article
Model Developing for Simulation of Multidroplet Dynamics in Water-in-Oil Emulsions under the Action of Electric Field
Accurate modeling of emulsion behavior in electric fields is essential to understand the electric-field-assisted water removal from crude oil. While most models focus on droplet pairs using various methods or on the entire emulsion using population balance models (PBM), the present work develops an intermediate model that uses the discrete element method (DEM) to calculate the trajectories of many droplets and the collision statistics within an emulsion. This intermediate model is necessary both for prioritizing studies of pairwise interactions and for calculating collision frequencies for PBM in the future. In this study, a preliminary version of the model was implemented that takes into account dipole-dipole interactions between droplets and their coalescence. The problem of trajectory divergence was addressed and it was demonstrated that the accuracy of the model can be assessed by analyzing the changes in the statistical distributions of the angles between the centerline connecting the colliding droplets and the electric field direction. In addition, the obtained statistics on collision parameters can be used for a more detailed study of pair interactions of droplets in an electric field.
Journal Article
TRPA1 Channel as a Regulator of Neurogenic Inflammation and Pain: Structure, Function, Role in Pathophysiology, and Therapeutic Potential of Ligands
TRPA1 is a cation channel located on the plasma membrane of many types of human and animal cells, including skin sensory neurons and epithelial cells of the intestine, lungs, urinary bladder, etc. TRPA1 is the major chemosensor that also responds to thermal and mechanical stimuli. Substances that activate TRPA1, e.g., allyl isothiocyanates (pungent components of mustard, horseradish, and wasabi), cinnamaldehyde from cinnamon, organosulfur compounds from garlic and onion, tear gas, acrolein and crotonaldehyde from cigarette smoke, etc., cause burning, mechanical and thermal hypersensitivity, cough, eye irritation, sneezing, mucus secretion, and neurogenic inflammation. An increased activity of TRPA1 leads to the emergence of chronic pruritus and allergic dermatitis and is associated with episodic pain syndrome, a hereditary disease characterized by episodes of debilitating pain triggered by stress. TRPA1 is now considered as one of the targets for developing new anti-inflammatory and analgesic drugs. This review summarizes information on the structure, function, and physiological role of this channel, as well as describes known TRPA1 ligands and their significance as therapeutic agents in the treatment of inflammation-associated pain.
Journal Article
Detonability of Suspensions of Explosives in Nitromethane
The detonability of mixtures of solid and liquid explosives (explosive suspensions) has been little studied although they are part of plastisol and paste explosive compositions widely used in practice. This paper presents an experimental study of the critical detonation diameters of suspensions of PETN, RDX, HMX, and FOX-7 of various dispersity (specific surface area 350–7000 cm
2
/g) in nitromethane. The concentration of crystalline explosives in suspensions was 3–60% (wt.). Suspensions were prepared using a vibrovacuum method. The sedimentation stability and homogeneity of suspensions were ensured by their thickening with a small addition of aerosil (2.0–2.5%). Charges of suspensions were prepared in thin-walled polyethylene terephthalate tubes of various diameter. Thus, the critical detonation diameter of explosive suspensions was determined for practically unconfined charges. The dependences of the critical detonation diameter of suspensions on the volume fraction of solid explosives have the same nearly S-shaped form. The effect of the dispersity of explosives on these dependences was shown. The obtained dependences for suspensions of solid explosives in nitromethane were compared with similar experimental dependences for other explosive systems: solutions of liquid explosives in nitromethane, solutions of solid explosives in nitromethane, binary mixtures of finely dispersed solid explosives, binary mixtures of coarsely and finely dispersed explosives, and compositions containing mixtures of coarsely and finely dispersed explosives and an inert binder. It was found that the dependences for the suspensions are similar to those for binary mixtures of coarsely-dispersed and micron-sized explosives and compositions based on these mixtures (distinct heterogeneous systems).
Journal Article
Differential Gain of THz Radiation in Crystalline Quartz in the Field of Pump Wave
We theoretically considered the possibility to exploit nonlinear Fabry–Pérot interferometers to differential gain of terahertz radiation in the field of a pump wave of the same frequency. It is shown that in a mirrorless nonlinear Fabry–Pérot interferometer, that consists of a crystalline quartz plate and which reflection is determined by Fresnel reflectivity only, the regime of maximal differential gain of radiation with central frequency at 1 THz can be observed at the plate thickness of near 1 mm and radiation intensity of 10
8
W cm
–2
order.
Journal Article