Solutions based on polymer-like micelles of ionic surfactants attract the attention of scientists as stimuli-responsive systems that can transform from a low-viscosity Newtonian fluid to a ...viscoelastic solution having a viscosity of up to 10 kPa s and an elastic response. The shape of micelles and their length are determined by the balance of hydrophobic and electrostatic interactions; therefore, the use of various low molecular weight substances or functional nanoparticles as additives can significantly change the rheological properties of such solutions and impart new stimuli-responsive properties to them. This review presents the most commonly used methods for controlling the properties of multicomponent solutions of wormlike surfactant micelles, including nanocomposite systems. Modern areas of practical application of such systems and prospects for their development are described.
In the south of the Russian Far East, a new promising type of source of strategic and critically important metals (titanium, gold, platinum, niobium, hafnium, copper, antimony, etc.) has been ...discovered: these are complex ores and placers that are spatially and genetically related to the Late Mesozoic (Cenomanian?) synorogenic intrusions of ultramafic–mafic rocks of the Sikhote-Alin orogenic belt. One example is the Ariadnensky massif of ultramafic, mafic and granitoid rocks with gold-titanium mineralization in its mafic part, gold-antimony mineralization at the exocontact, and gold-copper mineralization in the circum-intrusive zone. The main mineralogical and geochemical features of these ore formations have been determined. The typomorphic properties of native gold from ultramafic rocks have been revealed. It is shown that mantle and crustal processes were involved in the formation of different types of ore. The materials we obtained provide new opportunities for the reassessment of potential of strategic metal resources in Primorye.
Cerebral ischemia, and, as a result, insult, attacks up to 15 million people yearly in the world. In this connection, the development of effective preventive programs and methods of therapy has ...become one of the most urgent problems in modern angiology and pharmacology. The cytoprotective action of taxifolin (TAX) in ischemia is well known, but its limitations are also known due to its poor solubility and low capacity to pass through the hematoencephalic barrier. Molecular mechanisms underlying the protective effect of TAX in complex systems such as the brain remain poorly understood. It is known that the main cell types of the brain are neurons, astrocytes, and microglia, which regulate the activity of each other through neuroglial interactions. In this work, a comparative study of cytoprotective mechanisms of the effect of TAX and its new water-soluble form aqua taxifolin (aqTAX) was performed on cultured brain cells under ischemia-like conditions (oxygen-glucose deprivation (OGD)) followed by the reoxygenation of the culture medium. The concentration dependences of the protective effects of both taxifolin forms were determined using fluorescence microscopy, PCR analysis, and vitality tests. It was found that TAX began to effectively inhibit necrosis and the late stages of apoptosis in the concentration range of 30-100 µg/mL, with aqTAX in the range of 10-30 µg/mL. At the level of gene expression, aqTAX affected a larger number of genes than TAX; enhanced the basic and OGD/R-induced expression of genes encoding ROS-scavenging proteins with a higher efficiency, as well as anti-inflammatory and antiapoptotic proteins; and lowered the level of excitatory glutamate receptors. As a result, aqTAX significantly inhibited the OGD-induced increase in the Ca
levels in the cytosol (Ca
) in neurons and astrocytes under ischemic conditions. After a 40 min preincubation of cells with aqTAX under hypoxic conditions, these Ca
signals were completely inhibited, resulting in an almost complete suppression of necrotic death of cerebral cortical cells, which was not observed with the use of classical TAX.
We construct polynomial quantization (a variant of quantization in the spirit of Berezin) on para-Hermitian symmetric spaces. For that we use two approaches: (a) using a reproducing function, (b) ...using an “overgroup”. Also we show that the multiplication of symbols is an action of an overalgebra.
The results of the research of the conditions of the purification of the natural graphite with the usage of the processes of the hydrodifluoride technology are given. The interaction of the major ...impurity elements of the concentrate with NH4HF2 resulting in the formation of the complex fluorine ammonium salts and simple fluorides is established to occur during processing of the graphite concentrate with ammonium hydrodifluoride. Conducting the fluoridization with usage of 20% of surplus of NH4HF2 has been found to allow reaching the complete fluoridization of the impurity components which are present in the graphite. The complex fluorine ammonium salts and the fluorides of alkaline metals have appeared to be removed from fluoridated concentrate by means of the water leaching.
The rheological properties of hydrogels of a natural polysaccharide sodium alginate and small amount of clay nanotubes of halloysite were investigated. Changes of rheological properties during the ...transition from a semidiluted polymer solution to a hydrogel upon cross-linking by calcium ions were shown. In the gel state, the samples have a yield stress, and their viscosity decreases with the shear rate, but the properties are quickly recovered after the load removal. It was discovered that the addition of up to 0.3 vol % nanotubes of natural clay halloysite leads to an increase by several times of a storage modulus and a yield stress of the hydrogels. At the same time, the practically important properties of shear thinning and the rapid recovery of properties after the load removing make the nanocomposite hydrogels of alginate and halloysite nanotubes promising for use as ink for extrusion 3D printing.
A method for the coherent combining of two femtosecond laser beams based on acousto-optic interaction is proposed. Experimental studies have shown the possibility of forming a stationary interference ...pattern of two beams at the output of an acousto-optic cell when the ultrasound frequency coincides with the intermode interval in the femtosecond radiation spectrum. The intensity distribution between the two output beams is controlled by the amplitude and phase of the radio signal supplied to the acousto-optic cell.
Automata theory is one of the branches of mathematical cybernetics, that studies information transducers that arise in many applied problems. The major objective of automata theory is to develop ...methods by which one can describe and analyze the dynamic behavior of discrete systems. Depending on study tasks, automata are considered, for which the set of states and the set of output signals are equipped with additional mathematical structures preserved by the transition and output functions of automata. In this paper, we investigate automata over graphs and call them graphic automata. For graphs
a universal graphic automaton
is the universally attracted object in the category of graphic automata, for which the set of states is equipped with the structure of the graph
and the set of output signals is equipped with the structure of the graph
. The input signal semigroup of the universal graphic automaton is
. It may be considered as a derived algebraic system of the mathematical object
. It is common knowledge that properties of the semigroup are closely interconnected with properties of the algebraic structure of the automaton. This suggests that universal graphic automata may be researched using their input signal semigroups. In this article, we investigate the concrete characterization problem of graphic automata over reflexive graphs. The main result of our study states necessary and sufficient conditions for an automaton to be a universal graphic automaton over reflexive graphs.
The basic features of mineralogy and geochemistry of the gold-ilmenite placers, which are spatially and genetically associated with the Ariadnoye intrusion of ultrabasites (the right bank of the ...Ussuri River), are provided. The composition of platinum and gold was studied, and a complex of associated high-tech metals was revealed. It has been established that ultrabasites acted as the main supplier of useful components into the placers. Insightful mineralogical and geochemical studies of ore-bearing intrusions of ultrabasites of the Sikhote-Alin orogenic belt will expand the prospects for the raw material base of strategic metals in the southern part of the Far East.
•The bulk acoustic wave reflection from the crystal face influence on its structure.•The TeO2 acoustic anisotropy influence before the ultrasound beam reflection is low.•Low anisotropy before the ...reflection allows to form fairly homogeneous acoustic field.
Ultrasound wave reflection from one of the crystal faces is the convenient way to arouse the acoustic beam with a desired propagation direction in acousto-optic cells with collinear and quasi-collinear interaction geometries. The reflection process effects on the ultrasound field amplitude and phase structure. The method to simulate the reflected finite ultrasound beam structure in the case of acoustically anisotropic media is presented in this paper. The investigation is carried on the example of two quasi-collinear acousto-optic cells fabricated on the base of tellurium dioxide crystal. The cells have special geometry that allows to obtain extremely long acousto-optic interaction length and to achieve unprecedented spectral resolution. The influence of reflection process in the acousto-optic diffraction characteristics was also examined.
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