56 research outputs found

    Orientational Order-Disorder Effects in Molecular Crystals as Evidenced by Low-Frequency Raman Spectra

    Get PDF
    The studies of reorientational motions of molecules in crystals of organic compounds by low-frequency Raman spectroscopy are briefly reported. Some examples illustrate the efficiency of the investigation of order-disorder phenomena in organic crystals by the temperature dependence of low-frequency vibrational spectra combined with simultaneous calculations of the molecular dynamics by the atom-atom potentials (AAP) method. The conditions have been determined which are necessary in order to affect the low-frequency Raman spectra by anisotropy of molecular reorientations in crystals

    Postsynaptic GABA(B) receptors contribute to the termination of Giant Depolarizing Potentials in CA3 neonatal rat hippocampus

    Get PDF
    © 2017 Khalilov, Minlebaev, Mukhtarov, Juzekaeva and Khazipov. During development, hippocampal CA3 network generates recurrent population bursts, so-called Giant Depolarizing Potentials (GDPs). GDPs are characterized by synchronous depolarization and firing of CA3 pyramidal cells followed by afterhyperpolarization (GDP-AHP). Here, we explored the properties of GDP-AHP in CA3 pyramidal cells using gramicidin perforated patch clamp recordings from neonatal rat hippocampal slices. We found that GDP-AHP occurs independently of whether CA3 pyramidal cells fire action potentials (APs) or remain silent during GDPs. However, the amplitude of GDP-AHP increased with the number of APs the cells fired during GDPs. The reversal potential of the GDP-AHP was close to the potassium equilibrium potential. During voltage-clamp recordings, current-voltage relationships of the postsynaptic currents activated during GDP-AHP were characterized by reversal near the potassium equilibrium potential and inward rectification, similar to the responses evoked by the GABA(B) receptor agonists. Finally, the GABA(B) receptor antagonist CGP55845 strongly reduced GDP-AHP and prolonged GDPs, eventually transforming them to the interictal and ictal-like discharges. Together, our findings suggest that the GDP-AHP involves two mechanisms: (i) postsynaptic GABA(B) receptor activated potassium currents, which are activated independently on whether the cell fires or not during GDPs; and (ii) activity-dependent, likely calcium activated potassium currents, whose contribution to the GDP-AHP is dependent on the amount of firing during GDPs. We propose that these two complementary inhibitory postsynaptic mechanisms cooperate in the termination of GDP

    Frequency of malaria and glucose-6-phosphate dehydrogenase deficiency in Tajikistan

    Get PDF
    BACKGROUND: During the Soviet era, malaria was close to eradication in Tajikistan. Since the early 1990s, the disease has been on the rise and has become endemic in large areas of southern and western Tajikistan. The standard national treatment for Plasmodium vivax is based on primaquine. This entails the risk of severe haemolysis for patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Seasonal and geographical distribution patterns as well as G6PD deficiency frequency were analysed with a view to improve understanding of the current malaria situation in Tajikistan. METHODS: Spatial and seasonal distribution was analysed, applying a risk model that included key environmental factors such as temperature and the availability of mosquito breeding sites. The frequency of G6PD deficiency was studied at the health service level, including a cross-sectional sample of 382 adult men. RESULTS: Analysis revealed high rates of malaria transmission in most districts of the southern province of Khatlon, as well as in some zones in the northern province of Sughd. Three categories of risk areas were identified: (i) zones at relatively high malaria risk with high current incidence rates, where malaria control and prevention measures should be taken at all stages of the transmission cycle; (ii) zones at relatively high malaria risk with low current incidence rates, where malaria prevention measures are recommended; and (iii) zones at intermediate or low malaria risk with low current incidence rates where no particular measures appear necessary. The average prevalence of G6PD deficiency was 2.1% with apparent differences between ethnic groups and geographical regions. CONCLUSION: The study clearly indicates that malaria is a serious health issue in specific regions of Tajikistan. Transmission is mainly determined by temperature. Consequently, locations at lower altitude are more malaria-prone. G6PD deficiency frequency is too moderate to require fundamental changes in standard national treatment of cases of P. vivax

    Solar activity impact on the Earth’s upper atmosphere

    Get PDF
    The paper describes results of the studies devoted to the solar activity impact on the Earth’s upper atmosphere and ionosphere, conducted within the frame of COST ES0803 Action. Aim: The aim of the paper is to represent results coming from different research groups in a unified form, aligning their specific topics into the general context of the subject. Methods: The methods used in the paper are based on data-driven analysis. Specific databases are used for spectrum analysis, empirical modeling, electron density profile reconstruction, and forecasting techniques. Results: Results are grouped in three sections: Medium- and long-term ionospheric response to the changes in solar and geomag- netic activity, storm-time ionospheric response to the solar and geomagnetic forcing, and modeling and forecasting techniques. Section 1 contains five subsections with results on 27-day response of low-latitude ionosphere to solar extreme-ultraviolet (EUV) radiation, response to the recurrent geomagnetic storms, long-term trends in the upper atmosphere, latitudinal dependence of total electron content on EUV changes, and statistical analysis of ionospheric behavior during prolonged period of solar activity. Section 2 contains a study of ionospheric variations induced by recurrent CIR-driven storm, a case-study of polar cap absorption due to an intense CME, and a statistical study of geographic distribution of so-called E-layer dominated ionosphere. Section 3 comprises empirical models for describing and forecasting TEC, the F-layer critical frequency foF2, and the height of maximum plasma density. A study evaluates the usefulness of effective sunspot number in specifying the ionosphere state. An original method is presented, which retrieves the basic thermospheric parameters from ionospheric sounding data

    Demarcation of the Boundaries of the Central Asian Desert Natural Focus of Plague of Kazakhstan and Monitoring the Areal of the Main Carrier, <I>Rhombomys opimus</I>

    Get PDF
    The aim of the study was to clarify the boundaries of the Central Asian natural plague focus of Kazakhstan and the modern boundaries of the areal of the great gerbil (Rhombomys opimus) in order to improve epizootiological monitoring and increase the effectiveness of preventive (anti-epidemic) measures.Materials and methods. Data from the epizootiological monitoring of the great gerbil populations in 14 autonomous foci of the Central Asian desert natural plague focus in the Republic of Kazakhstan between 2010 and 2020 were used for the analysis. An epizootiologic survey of an area of 875350 km2 was carried out. When processing the data, epidemiological, epizootiological, statistical research methods, as well as GIS technologies were used.Results and discussion. An increase in the total area of the Central Asian desert natural plague focus of the Republic of Kazakhstan by 79710 km2 (9.98 %) has been established for the period of 1990–2020. It is noted that the change in the area of plague-enzootic territory was a consequence of the ever changing areal of the main carrier of plague pathogen – the great gerbil – under the influence of climatic and anthropogenic factors. The most significant changes were found in the southeastern part of the plague-enzootic territory, including those for the Betpakdala (50 %), Balkhash (34.3 %), Taukum (13.3 %) and Mojynkum (0.32 %) autonomous foci. The area of the Aryskum-Dariyalyktakyr autonomous focus decreased by 2100 km2 (4 %). In 2000–2002, new Alakol’sky and Ili intermountain autonomous foci with a total area of 26759 km2 were discovered. It is shown that due to the regression of the Aral Sea, the areal of the great girbil expanded and the area of the North Aral and Kyzylkum natural plague foci increased by 10500 km2 (29.2 %) and 560 km2 (0.4%), respectively. The areas of the Aral-Karakum and UralEmba desert autonomous foci, on the contrary, decreased by 2000 km2 (2.6 %) and 12300 km2 (17.6 %), respectively. Passportization and landscape-epizootiologic zoning of the territory of the Central Asian desert natural plague focus of the Republic of Kazakhstan has been completed

    Клиническая эффективность и безопасность применения ингаляционного простациклина у больных с инфекцией, вызванной SARS-CoV-2 (проспективное сравнительное исследование)

    Get PDF
    Aim. In this study we evaluated clinical effectiveness and safety of nebulized prostacyclin in patients with Novel Coronavirus Disease (SARS-CoV-2). Materials and methods: We have included 44 male patients with moderate PCR confirmed SARS-CoV-2 infection in this study. Control group consisted of 23 patients treated with nebulized prostacyclin (PGI2). besides standard therapy. We compared intensiveness and duration of infectious intoxication syndrome, duration of fever, cough as well as SpO2 level, complete blood count and chemokine status values. Results: Statistically significant difference in duration of fever, cough, intensiveness and duration of infectious intoxication syndrome were observed. Lymphocyte and platelet counts were significantly higher in control group We have also noticed significantly lower level of proinflammatory mediators and C4-complement component in control group. Only 1 adverse effect associated with inhaled prostacyclin was reported. Conclusion. Nebulized prostacyclin showed therapeutic efficacy and good safety profile in adults with moderate COVID-19.Цель: оценка клинической эффективности и безопасность ингаляционного простациклина у пациентов с новой коронавирусной инфекцией (SARS-CoV-2). Материалы и методы: в исследование были включены 44 пациента мужского пола с подтвержденной новой коронавирусной инфекцией среднетяжелого течения. Опытную группу составили 23 пациента, которым, помимо стандартной терапии, был назначен ингаляционный простациклин (PGI2). Клиническая эффективность илопроста была оценена по длительности и выраженности общеинфекционных синдромов (интоксикации, лихорадки), длительности кашля, уровню насыщения крови кислородом, значениям параметров общеклинического анализа крови, показателю иммунологического статуса пациентов. Результаты: получено статистически значимое снижение длительности лихорадки, продолжительности кашля, выраженности и длительности синдрома общей инфекционной интоксикации в опытной группе. Также отмечено, что у этих пациентов средние значения количества лимфоцитов, тромбоцитов достоверно увеличивалось, а значение СОЭ снижалось. Средние значения провоспалительных цитокинов, хемокинов, а также С4-компонента комплемента были статистически значимо ниже, чем у больных COVID-19 в группе сравнения. Нежелательные реакции, связанные с инга ляционной терапией простациклином, были отмечены в 1 наблюдении. Заключение: показана терапевтическая эффективность и хороший профиль безопасности ингаляционного простациклина у пациентов с COVID-19 средней степени тяжести

    Global Dynamics of the MLT

    Full text link

    Postsynaptic GABA(B) receptors contribute to the termination of Giant Depolarizing Potentials in CA3 neonatal rat hippocampus

    No full text
    © 2017 Khalilov, Minlebaev, Mukhtarov, Juzekaeva and Khazipov. During development, hippocampal CA3 network generates recurrent population bursts, so-called Giant Depolarizing Potentials (GDPs). GDPs are characterized by synchronous depolarization and firing of CA3 pyramidal cells followed by afterhyperpolarization (GDP-AHP). Here, we explored the properties of GDP-AHP in CA3 pyramidal cells using gramicidin perforated patch clamp recordings from neonatal rat hippocampal slices. We found that GDP-AHP occurs independently of whether CA3 pyramidal cells fire action potentials (APs) or remain silent during GDPs. However, the amplitude of GDP-AHP increased with the number of APs the cells fired during GDPs. The reversal potential of the GDP-AHP was close to the potassium equilibrium potential. During voltage-clamp recordings, current-voltage relationships of the postsynaptic currents activated during GDP-AHP were characterized by reversal near the potassium equilibrium potential and inward rectification, similar to the responses evoked by the GABA(B) receptor agonists. Finally, the GABA(B) receptor antagonist CGP55845 strongly reduced GDP-AHP and prolonged GDPs, eventually transforming them to the interictal and ictal-like discharges. Together, our findings suggest that the GDP-AHP involves two mechanisms: (i) postsynaptic GABA(B) receptor activated potassium currents, which are activated independently on whether the cell fires or not during GDPs; and (ii) activity-dependent, likely calcium activated potassium currents, whose contribution to the GDP-AHP is dependent on the amount of firing during GDPs. We propose that these two complementary inhibitory postsynaptic mechanisms cooperate in the termination of GDP
    corecore