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The worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) famously known as the COVID-19 pandemic is making shocking sceneries all over the globe. The COVID-19 virus can survive on the surface of several materials and infect the person that comes in contact with that surface during the virus lifespan. Therefore, it is recommended to ensure that bacteria, microorganisms, and viruses, including COVID-19, are eliminated from food surfaces. In this work, a study has been conducted based on COMSOL Multiphysics to evaluate the temperature at micro-droplet surfaces located at different positions and locations in microwave ovens, which are used globally to reheat food. It was found that the micro-droplet surface temperature within two and a half minutes is enough to kill the bacterial and viral microorganisms on the droplet surface. As COVID cannot tolerate 70 degreeC temperature, within this time, it can be eliminated from the food surface. The time requirement can be shortened by using high-power microwave ovens.Copyright © 2022 The Authors
RESUMO
Erythrocytes of 40 patients (11 men and 29 women, average age 52.2 +/- 13.2 years), COVID-19 convalescents (within 2 - 4 months after the disease), were studied by dielectrophoresis using an electro-optical cell detection system in a nonuniform alternating electric field. Cytoflavin at a concentration of 1:30 (v:v) after incubation with erythrocytes (1,6 - 1,8 x 108/ml) for 10 minutes caused an increase by 24 - 63% on average in the share of discocytes, amplitude of deformation, speed of cell movement towards electrodes, magnitude of the dipole moment, capacity of the erythrocyte membranes, and in the polarizability at a frequency of 106 Hz and relative polarizability (p = 0.05 - 0.0001). On the contrary, a decrease by 27 - 49% on average is observed in the composite indicators of viscosity, cell rigidity, electrical conductivity, aggregation index, degree of hemolysis at different frequencies of the electric field (p = 0.05 - 0.002). A shift of the crossover frequency of erythrocytes (from the position of the frequency regions of negative and positive dielectrophoresis) to the low-frequency range is revealed (p < 0.0001). The analysis of data using the Volcano-plot method (paired and unpaired statistics) showed that the degree of erythrocyte deformation at a frequency of 0.5 . 106 Hz, relative polarizability, the position of the crossover frequency, membrane capacity and polarizability of cells at different frequencies of the electric field appeared to be the most sensitive to the action of cytoflavin. Thus, the action of cytoflavin triggers the processes optimizig the rheological properties of erythrocytes of patients underwent COVID-19 which is rather important for adequate micro- and macrocirculation of blood and allows expanding indications for the use of the drug in patients of this category. Copyright © 2022 Izdatel'stvo Meditsina. All rights reserved.
RESUMO
Objective: The purpose is to identify the peculiarities of the parameters of red blood cells (RBC) and hemostasis in patients with strokes associated with coronavirus infection. Design and method: A total of 124 patients (48.5 + 1.9 years) with impairments of cerebral circulation due to COVID-19 (confirmed by positive PCR test) had been examined. Among them, 74 patients had ischemic stroke, 25- transient ischaemic attack, 17- intracerebral hemorrhage, 8- subarachnoid hemorrhage. The parameters of hemostasis were measured by standard methods, electrical, viscoelastic parameters of RBC - by dielectrophoresis. Results: 71 patients (the 1st group) showed signs of intravascular coagulation and thrombosis: accelerated platelet-leukocyte aggregation, increased levels of coagulation products, reduced fibrinolysis activity (p = 0.001-0.04). The levels of D-dimer, fibrinogen, ESR, platelet count were higher in this group compared to the second one (p < 0.01). A moderate increase of RBC summarized rigidity, viscosity was noted. The level of RBC hemolysis was associated with platelet count (r = 0.735,p = 0.03), D-dimer (r = 0.482, p < 0.05), fibrinogen level (r = 0.374, p = 0.04). In 2nd group (53 persons), the markers of thrombosis had moderate deviations. Sharply reduced RBC deformability with increased summarized rigidity, viscosity was dominant coupled with the background of high electrical conductivity of cell membranes compared to the indicators in the 1st group (p < 0.01). There was a decrease of membrane capacity, surface charge, cell dipole moment, polarizability than those in the 1st group (p = 0.0001-0.05). A sharp decrease of RBC deformability creates obstacles to overcoming small-diameter capillaries, leading to violations of microcirculatory blood flow. RBC deformability was associated with levels of ferritin (r = 0.451, p = 0.02), HbA1c (r = 0.480, p = 0.03), uric acid (r = -0.371, p < 0.05), LDL cholesterol (r = 0.461, p = 0.02). Incubation of blood samples in vitro for 10 min with riboflavin, nicotinamide, inosine, which ensures RBC energy metabolism, restored the reduced RBC deformability (p < 0.01), altered cell morphology (p = 0.04), decreased RBC aggregation (p < 0.001). Conclusions: The revealed features of parameters of RBC hemostasis in stroke patients with coronavirus infection are associated with two independent pathogenetic mechanisms: thrombotic and hemorheologic. The thrombotic variant is due to procoagulant state and an activity of inflammation. The hemorheologic variant is caused by decrease of RBC energy metabolism, activity of enzymes.