Kinetic coefficients of semiconductor superlattice are obtained from the Boltzmann transport equation with Bhatnagar-Gross-Krook (BGK) collision term and Poisson equation. Using the universal ...analytic procedure, we found kinetic coefficient in the quasistatic limit starting from the exact solution of the Boltzmann transport equation. It is shown that the Einstein relation for the diffusion coefficient is applicable only for weak fields and it is not valid in the general case. As a consequence, a drift-diffusion model of miniband transport in the case of strong dc and ac fields should be corrected, taking into account the kinetic coefficients obtained from the Boltzmann equation.
The study of the features of the clinical course of pregnancy, childbirth in women who have had COVID-19 at different periods of gestation is relevant, especially in the context of a modern pandemic. ...Purpose of work. To determine the features of the clinical course of pregnancy, childbirth in women with COVID-19 at different periods of gestation. Materials and methods. 57 women who were ill with Covid-19 at different stages of pregnancy were examined. Results and discussion. The peculiarities of the clinical course of pregnancy, childbirth in women who have undergone Covid-19 diseases in the 1st trimesterinclude the syndrome of threatened abortion (73.6 %), placental dysfunction (100%), fetal growth retardation syndrome (42.9 %); in the second trimester - syndrome of threatened premature birth (55.6 %), placental dysfunction (100 %), amniotic fluid pathology (63.2 %); in the third trimester - anemia - in 100 %, antenatal fetal distress - in 42.1 %, pareclampsia - in 47.4 %, pathological blood loss - in 26.3 %. Conclusions. The course of pregnancy and childbirth in women who have undergone COVID-19 diseases in different trimesters of gestation have certain clinical features. Gestational complications in women who were ill in the early stages of the first trimester include the syndrome of threatened abortion, spontaneous abortion, missed abortion, premature birth in the second trimester, fetal growth retardation syndrome in the second and third trimesters. The gestational complications in women who were ill in the second trimester include the syndrome of threatened abortion, premature birth, pathology of amniotic fluid (amniotic fluid of «black» color), the phenomenon of angiitis in the abdominal cavity, placental dysfunction, fetal growth retardation syndrome, distress fetus, antenatal fetal death. The gestational complications in women who were ill in the third trimester include the syndrome of threatened premature birth, placental dysfunction, and fetal distress.
The association between vitamin D deficiency and the severity of COVID-19 is currently being actively discussed around the world.
The aim of this study was to assess the prevalence of vitamin D ...insufficiency and deficiency and compare it with the incidence rates of SARS-CoV-2 in eight Federal Districts of the Russian Federation.
We included 304,564 patients (234,716 women; 77,1%) with serum 25(OH)D levels results performed September 2019 through October 2020.
Only 112,877 people (37.1%) had a normal serum 25(OH)D level, others had a deficiency. Vitamin D insufficiency and deficiency was presented with the same frequency in women and men, and no differences were found depending on the geographical location and age in subjects from 18 to 74 years old. However, subjects over 75 years more often had vitamin D deficiency, while subjects under 18 years had normal levels in over 50% cases. In addition, 21,506 patients were tested for SARS-CoV-2 by PCR with further comparison of results with serum 25(OH)D level. The SARS-CoV-2 positivity rate was detected in 3,193 subjects, negative in 18,313. There were no differences in the morbidity in a vitamin D deficiency and a normal level. Thus, 14.8% subjects had positive PCR rates among vitamin D deficiency patients (4,978 tests), 14.9% when 25(OD)D level was from 20 to 30 ng/ml (7,542 tests), 15.0% among those who had 25(OH)D 30- 50 ng/ml (6,622 tests), and 13.9% when vitamin D was more than 50 ng/ml (4,612 tests).
There was no association between the COVID-19 incidence and vitamin D status in different regions of Russia. Although the nutrient deficiency persists in all regions and is most often diagnosed in people over 75 years old.
In gel-filtration of Cl. perfringens type A toxin on Sephadex F-100 and F-50 there was revealed relationship between the leukotoxic activity and a high-molecular component. A method of ion-exchange ...chromatography on a column with DEAE-Sephadex A-25 from the Cl. perfringens toxin there were obtained 8 fractions 3 of which possessed a marked leukotoxic activity: the capacity to destroy neutrophils in the Svejcar and Vancurik test and to-depress the phagocytic activity of leukocytes. Lecithinase and lethal activity was revealed in one of these fractions only. Leukotoxic fractions differed by the capacity to destroy neutrophils and to decrease their phagocytic activity.
PDF
