Investigation of DNA denaturation in Peyrard-Bishop-Dauxois model by molecular dynamics method

The phase transition of $(PolyA/PolyT)_{100}$ duplex into the denaturated state is studied in the Peyrard-Bishop-Dauxois model by the method of direct molecular-dynamical modeling. The temperature dependencies of the total energy and heat capacity of the duplex are calculated. The approach applied can be used to calculate the statistical properties of the duplexes of any length and nucleotide composition.Comment: 6 pages, 4 figure

A mortal case of coronavirus disease in a pregnant diabetic woman. Clinical case

Pregnant women are very susceptible to coronavirus infection. Gestational diabetes mellitus is severe comorbidity and a serious risk factor for lethal outcomes. We report a mortal case of coronavirus disease (COVID-19) associated with bilateral pneumonia and systemic inflammatory response syndrome in a pregnant woman with gestational diabetes mellitus. Patient was admitted to the hospital at 31 weeks of gestation with COVID-19 bilateral pneumonia. Anti-inflammatory, antiviral, antibacterial and immunomodulatory treatment was started. She received per os favipiravir 200 mg, azithromycin 500 mg, enfluvir 75 mg, plaquenil 200 mg, and ceftriaxone 1 g intravenously, piperacillin 4.5 g intravenously, methylprednisolone 40 mg intramuscular, enoxaparin 0.6 subcutaneously. The doses of insulin were changed. But maternal status became worse in several hours. Oxygen saturation dropped to 80%. Patient was intubated and connected to the artificial lung ventilator. The cesarean was performed. The preterm born baby with early neonatal sepsis diseased the next day. The treatment could not counteract an inflammatory storm. Despite intensive resuscitation, the woman diseased. The fatal case of COVID-19 was associated with coexisted gestational diabetes mellitus and late admission to the hospital. The COVID-19 patients with gestational diabetes mellitus are at higher risk of severe pneumonia, systemic inflammatory response and carbohydrate metabolism decompensation. Oxidative stress caused by bilateral pneumonia initiated the chain of tissue injury-related reactions. The fat tissue is an additional source of free radicals and proinflammatory cytokines. Progression of the proinflammatory scenario enhanced multiple organ failure. We have found signs of acute pulmonary, hepatic, and renal insufficiency. The unresponsiveness to treatment contributed to systemic inflammatory response and maternal deterioration. Further investigations are necessary to improve outcomes in COVID-19 during pregnancy

Delayed neurological maturation is a cause for distress during fetal growth restriction

Theory of fetal programming contributes to a better understanding of the relationship of many human diseases with antenatal period pathology. Regulatory impact of nervous system is of great importance. Fetal growth restriction (FGR) is a convenient model for investigation of the abnormalities of fetal neurodevelopment. Fetal heart rate variability is a well-known approach for fetal autonomic function detection. The aim of the study was to detect several patterns of autonomic nervous regulation in FGR complicated by fetal distress or without fetal distress. Materials and methods. Totally 64 patients at 26–28 weeks of gestation were enrolled. 23 patients had normal fetal growth and were included in the Group I (control). 20 pregnant women with FGR without fetal distress were observed in Group II. 21 patients with FGR and fetal distress were included in Group III. Fetal heart rate variability and conventional cardiotocographic patterns were obtained from the RR-interval time series registered from the maternal abdominal wall via non-invasive fetal electrocardiography. Results. Suppression of the total level of heart rate variability with sympathetic overactivity was found in FGR. The maximal growth of sympathovagal balance was found in Group III. Fetal deterioration was associated with an increased quantity of decelerations, reduced level of accelerations, and decreased of short term variations and low term variations. But a decelerative pattern before 26 weeks of gestation was normal. Therefore fetal autonomic malfunction could be a result of persistent neurological immaturity in FGR. The approach based on the monitoring of fetal autonomic maturity in the diagnosing of its well-being should be tested in further studies. Conclusion. Fetal heart rate variability variables and beat-to-beat variations parameters could be the sensitive markers of neurological maturation and good predictors for fetal deterioration

Operator method in solving non-linear equations of the Hartree-Fock type

The operator method is used to construct the solutions of the problem of the polaron in the strong coupling limit and of the helium atom on the basis of the Hartree-Fock equation. $E_0=-0.1085128052\alpha^2$ is obtained for the polaron ground-state energy. Energies for 2s- and 3s-states are also calculated. The other excited states are briefly discussed.Comment: 7 page

Building Heat-insulating Materials Based on the Products of the Transesterification of Polyethylene Terephthalate and Dibutyltin Dilaurate

In this paper, we offered a technological basis for production of heat-insulating polyurethane materials based on the aromatic polyester - the product of transesterification of polyethylene terephthalate and corrective additive - dibutyltin dilaurate. Also, we presented the formulation and properties of the developed polyurethanes

Glass-filled polyurethane materials produced by fiber composite spraying

© 2017, Allerton Press, Inc. By using polymer composites in auto parts, the vehicle mass may be considerably reduced, with improvement in the dynamic properties and load capacity of the vehicle and also in its fuel consumption and tailpipe emissions. In the present work, recommendations are made for improving the performance of glassfilled polyurethane materials produced by fiber composite spraying. To that end, the thermal stability, impact strength, high-temperature strength, and Shore D hardness are determined in accordance with Technical Specifications TU 2292-010-14682925–2014. The sound absorption and UV resistance of the composites are also determined