hydrate shell
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2021 ◽  
Vol 12 (5) ◽  
pp. 7102-7110

The formation of fibrin clots determines the characteristics of blood plasma coagulation. It is known that small molecules like nitrogen and carbon monoxides have a toxic effect at high concentrations due to the competitive binding to hemoglobin, preventing further oxygen transfer. The mechanisms of intoxication with these gases have been extensively studied in the literature, but there is little information on their effects on other vital processes. In particular, blood coagulation parameters have not been studied, although prolonged exposure to relatively low concentrations of gases can cause significant pathological changes. In this paper, the characteristics of the fibrin-polymer after coagulation of a blood plasma sample under conditions of pretreatment with gases were studied using FTIR-spectroscopy. The changes in the vibrations of individual bonds and fragments in the Amide I and Amide B regions are shown and analyzed. It was established that at concentrations of CO exceeding the endogenous levels, the connector α-helix unfolds and β-structures form, leading to the loss of part of the hydrate shell, the formation of a fibrin clot with a disordered structure of higher density due to an increase in its hydrophobicity. For cases where samples were treated with NO gas, the degree of aggregation of the fibrin clot from plasma incubated with nitroglycerin was one-quarter less than the original, the proportion of α-helices was not reduced, and there were no disordered structures in the clot. This may indicate a lower clot density and probably easier lysis of the one.


Author(s):  
Ludger Klimek ◽  
Natalija Novak ◽  
Beatriz Cabanillas ◽  
Marek Jutel ◽  
Jean Bousquet ◽  
...  

Following the emergency use authorization of the vaccine mRNA-1273 on 18th December 2020 in the US and the vaccine BNT162b2 one week earlier, two mRNA vaccines are in currently used for the prevention of coronavirus disease 2019 (COVID-19). Phase 3 pivotal trials on both vaccines excluded individuals with a history of allergy to vaccine components. Immediately after the initiation of vaccination in the United Kingdom, Canada, and in the US, anaphylactic reactions have been reported. While the culprit trigger requires investigation, initial reports suggested the excipient polyethylene glycol 2000 (PEG-2000), which is contained in both vaccines as PEG-micellar carrier system as the potential culprit. Surface PEG chains form a hydrate shell to increase stability and prevent opsonization. Allergic reactions to such PEG-ylated lipids are rarely IgE-mediated, but may result from complement activation-related pseudoallergy (CARPA) that has been described to similar liposomes. In addition, mRNA-1273 also contains tromethamine (trometamol), which has been reported to cause anaphylaxis to e.g. gadolinium-based or iodinated contrast media. Skin prick-, intradermal-, epicutaneous- tests, in vitro sIgE assessment, evaluation of sIgG/IgM, as well as basophil activation test are in use to demonstrate allergic reactions to various components of the vaccines.


Author(s):  
Jin Zhang ◽  
An Chen ◽  
Menglan Duan

In order to master the microscopic growth mechanism of natural gas hydrate, a series of experiments were carried out using a high-pressure hydrate flow loop. The microscopic physical information of the growth of hydrates in the emulsion system is captured by advanced microscopic equipment and the phenomena of the experiments show that: 1) not all water droplets instantaneously generate a hydrate shell, but only a few of the water droplets gradually generate a hydrate shell when reaching the conditions of the hydrate formation; and 2) the coalescence and shear do occur in the hydrate formation process, and the distribution of hydrate particle size has changed.


Author(s):  
Mikhail F. Butman ◽  
Natalya V. Filatova ◽  
Galina P. Kozlovskaya

Here are discussed some results to use oxyethylidenediphosphonic acid (OEDPA) and various additives as a deflocculant composition for controlling the rheological properties of a ceramic suspension. According to the results of determining thixotropy, it was found that a complex thinner based on soda and OEDPA is the most effective. It is desirable to replace a portion of the soda with liquid glass. By the full factorial experiment method, it was established the optimal composition of the components of the complex thinner. The proposed thinner is highly effective in a wide range of OEDPA, soda, and liquid glass concentrations. The resulting suspensions have stable, high structural–mechanical properties. A mathematical model describing the effect of the composition of the thinner on the viscosity and thixotropy of the suspension is presented. The effect of the diluent on the mechanical properties of the molded dried and fired samples was determined. The addition of OEDPA to the thinner significantly lowers the rheological parameters and the rheological properties of the suspensions approach the rheological properties of Newtonian systems. It was found that OEDPA lowers the mass buildup rate, which can be increased by lowering the moisture content in the suspension, which makes it possible to increase the post-casting and -drying density of the samples. The introduction of this additive leads to an increase in the hydrate shell around the clayey particle and an increase in the stability of the suspension, but the increase in the ζ - potential in comparison with the production additive is very small. The mechanism of action of a complex additive is proposed, including ion-exchange, complexation and chemisorption. An increase in the strength and density of dry and calcinated clay samples as well as a decrease in the shrinkage and porosity are observed. The complex additive makes it possible to optimize the technology at the stages of casting slip and to decrease the number of parts rejected during molding, drying and firing.


2020 ◽  
Vol 108 (5) ◽  
pp. 375-382
Author(s):  
Julia V. Kondakova ◽  
Christina D. Khoroshilova ◽  
Alexey B. Sazonov

AbstractDistribution of tritium between vapor and lithium chloride aqueous solutions at 30–80 °C has been studied with the aid of vacuum distillation technique. “Positive” H/T VPIE (separation ratio increases with solute concentration) was observed. This ratio depends linearly on the salt molality and decreases with temperature. The results are in agreement with theoretical estimates of “free” water – hydrate shell H/T isotope equilibrium constants done with DFT force field calculations and harmonic oscillator quantum statistics. Found growth of the separation ratio may be practically important for developing extractive distillation process to remove tritium from technological solutions and liquid wastes of nuclear industry.


2019 ◽  
Vol 207 ◽  
pp. 1-16 ◽  
Author(s):  
Baojiang Sun ◽  
Zheng Liu ◽  
Zhiyuan Wang ◽  
Litao Chen ◽  
Hao Li ◽  
...  

Author(s):  
Mykola Shatalov

As a result of the analysis of space, geological and tectonic information, it was established that the true causes of natural ecolymnological disasters in Cameroon in 1984 and 1986 were modern fault-block tectonic movements, which are closely associated with seismic and geodynamics in one of the sections of the “living” Adamawa Mountains. The main cause of catastrophes must be considered the activation of endogenous processes occurring in the mantle and the tectonosphere of the Earth. Cosmo- and rotogenesis of the planet Earth, in the near-surface parts of the Earth’s crust of the Adamava mountain segment, led to intensive mountain-building and heat exchange processes, the causes and mechanism of which are closely associated with the rise of abnormally hot magmatic material and gas-liquid fluids containing CO2 from the mantle. Favorable transport routes for heat and mass transfer in the Earth’s lithosphere are volcanic channels, as well as the orthogonal and diagonal network of deep faults. At the same time, volcanic channels should be considered as unique drain pipes of our planet. The lethal carbon dioxide ejected from the depths of Lakes Nyos and Monun is mainly a differentiate of igneous melts, and the latter, in turn, have mantle “roots” extending to a depth of 200–300 km. The volcano-crater lakes Nios and Monun are confined to the nodes of the intersection of “living” deep faults, revealing the deep horizons of the planet, where in magmatic foci CO2 is predominant as products of differentiation. The author proposed a mechanism for the formation of a solid gas hydrate shell, a relatively tightly sealed volcanic crater. This giant gas hydrate plug prevented the gradual-passive circulation, i. e. outflow of CO2 into the hydrosphere and atmosphere coming from deep and intermediate magmatic foci. So, under the gas hydrate shell of the lakes Nios and Monun, a large amount of CO2 accumulated. Explosive emissions of significant amounts of lethal gas could appear only with the geodynamic activation of the earth’s crust, where these unique volcano-crater lakes are located. Seismotectonic processes contributed to the destruction of the gas hydrate shell and the breakthrough of CO2 through fractures, cracks and through the water membrane to the surface. Emissions of gases on the volcano-crater lakes Nyos and Monun are the brightest example (indicator) of the Earth’s carbon dioxide-deep degassing.


2019 ◽  
Vol 97 (6) ◽  
pp. 1953-1960 ◽  
Author(s):  
Xiaohui Sun ◽  
Andi Xia ◽  
Baojiang Sun ◽  
Youqiang Liao ◽  
Zhiyuan Wang ◽  
...  

2019 ◽  
Vol 14 (2) ◽  
pp. 142-147
Author(s):  
S.R. Kildibaeva ◽  
E.T. Dalinskij ◽  
G.R. Kildibaeva

The paper deals with the case of damage to the underwater pipeline through which oil and associated gas are transported. The process of oil and gas migration is described by the flow of a multiphase submerged jet. At the initial moment, the temperature of the incoming hydrocarbons, their initial velocity, the temperature of the surrounding water, the depth of the pipeline is known. The paper considers two cases of different initial parameters of hydrocarbon outflow from the pipeline. In the first case, the thermobaric environmental conditions correspond to the conditions of hydrate formation and stable existence. Such a case corresponds to the conditions of the hydrocarbons flow in the Gulf of Mexico. In the second case, hydrate is not formed. Such flows correspond to the cases of oil transportation through pipelines in the Baltic sea (for example, Nord stream–2). The process of hydrate formation will be characterized by the following dynamics of the bubble: first, it will be completely gas, then a hydrate shell (composite bubble) will begin to form on its surface, then the bubble will become completely hydrate, which will be the final stage. The integral Lagrangian control volume method will be considered for modeling the dynamics of hydrocarbon jet propagation. According to this method, the jet is considered as a sequence of elementary volumes. When modeling the jet flow, the laws of conservation of mass, momentum and energy for the components included in the control volume are taken into account. The equations are used taking into account the possible formation of hydrate. Thermophysical characteristics of hydrocarbons coming from the damaged pipeline for cases of deep-water and shallow-water pipeline laying are obtained. The trajectories of hydrocarbon migration, the dependence of the jet temperature and density on the vertical coordinate are analyzed.


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