Synthesis of Novel Iono- and Photochromic Spiropyrans Derived from 6,7-Dihydroxy-8-Formyl-4-Methyl-2H-Chromene-2-One

Novel photochromic spiropyrans (SPPs) containing 6′-hydroxy group were synthesized and their spectral properties as well as abilities for complexation with metal ions studied. In solutions they exist as equilibrium mixture of spirocyclic (A) and merocyanine (B) isomers. The largest content of merocyanine form was found for the derivative with an electron-donating methyl group in position 5 of hetaryl fragment. The irradiation of SPPs in acetonitrile shifts the equilibrium to the B form. Similar effect causes the addition of metal cations due to formation of colored complexes with merocyanine isomers

Menstrual function and mental health of medical students during the COVID-19 pandemic: a continuous cross-sectional study

Aim. To assess the impact of new coronavirus infection (NCI) and COVID-19 vaccination on menstrual function in comparison with the frequency of depressive disorders during the COVID-19 pandemic among female students of a medical university. Materials and methods. Data for a continuous transverse (cross-sectional) study were obtained using an online survey. The questions included demographics, characteristics of menstrual function, the history of COVID-19 and vaccinations against it, and the standard CES-D (Center for Epidemiologic Studies Depression Scale) questionnaire. The survey included 1.879 female medical students. The exclusion criteria were age under 18 and over 25 years, hormonal contraceptives, pregnancy, childbirth during the last year, and vaccination after COVID-19. After applying the exclusion criteria, three study groups were formed. Group 1 included female students with a history of NCI (n=140), group 2 included students with no history of NCI, who were initially vaccinated against COVID-19 (n=647), group 3 (control group) included unvaccinated students with no history of NCI (n=55). Results. There were no differences in the prevalence of changes in menstrual function in female students after the NCI (49.3%) and after COVID-19 vaccination (39.6%) compared to the control group (43.6%); p=0.477. The rate of depression in the overall study cohort was 43.3%, without any significant differences between the study groups. Significant predictors of changes in menstrual function during the pandemic were marriage (odds ratio OR 2.33 [1.513.61]), depression (OR 1.72 [1.282.3]), a history of menstrual dysfunction (OR 1.5 [0.121.99]), and later menarche (OR 1.76 [1.023.04]). Multivariate analysis did not show the significance of the history of NCI and vaccination as factors of menstrual dysfunction (OR 1.61 [0.892.90] and OR 0.91 [0.591.41], respectively). Conclusion. During the COVID-19 pandemic, female medical students reported frequent changes in menstrual function and depressive disorders. During the pandemic, the most significant predictors of menstrual disorders in female students were depression, a history of menstrual dysfunction, and marriage. A multicenter prospective study is necessary to clarify the mechanisms of the pandemic's impact on menstrual function

Albiglutide and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease (Harmony Outcomes): a double-blind, randomised placebo-controlled trial

Background: Glucagon-like peptide 1 receptor agonists differ in chemical structure, duration of action, and in their effects on clinical outcomes. The cardiovascular effects of once-weekly albiglutide in type 2 diabetes are unknown. We aimed to determine the safety and efficacy of albiglutide in preventing cardiovascular death, myocardial infarction, or stroke. Methods: We did a double-blind, randomised, placebo-controlled trial in 610 sites across 28 countries. We randomly assigned patients aged 40 years and older with type 2 diabetes and cardiovascular disease (at a 1:1 ratio) to groups that either received a subcutaneous injection of albiglutide (30–50 mg, based on glycaemic response and tolerability) or of a matched volume of placebo once a week, in addition to their standard care. Investigators used an interactive voice or web response system to obtain treatment assignment, and patients and all study investigators were masked to their treatment allocation. We hypothesised that albiglutide would be non-inferior to placebo for the primary outcome of the first occurrence of cardiovascular death, myocardial infarction, or stroke, which was assessed in the intention-to-treat population. If non-inferiority was confirmed by an upper limit of the 95% CI for a hazard ratio of less than 1·30, closed testing for superiority was prespecified. This study is registered with ClinicalTrials.gov, number NCT02465515. Findings: Patients were screened between July 1, 2015, and Nov 24, 2016. 10 793 patients were screened and 9463 participants were enrolled and randomly assigned to groups: 4731 patients were assigned to receive albiglutide and 4732 patients to receive placebo. On Nov 8, 2017, it was determined that 611 primary endpoints and a median follow-up of at least 1·5 years had accrued, and participants returned for a final visit and discontinuation from study treatment; the last patient visit was on March 12, 2018. These 9463 patients, the intention-to-treat population, were evaluated for a median duration of 1·6 years and were assessed for the primary outcome. The primary composite outcome occurred in 338 (7%) of 4731 patients at an incidence rate of 4·6 events per 100 person-years in the albiglutide group and in 428 (9%) of 4732 patients at an incidence rate of 5·9 events per 100 person-years in the placebo group (hazard ratio 0·78, 95% CI 0·68–0·90), which indicated that albiglutide was superior to placebo (p<0·0001 for non-inferiority; p=0·0006 for superiority). The incidence of acute pancreatitis (ten patients in the albiglutide group and seven patients in the placebo group), pancreatic cancer (six patients in the albiglutide group and five patients in the placebo group), medullary thyroid carcinoma (zero patients in both groups), and other serious adverse events did not differ between the two groups. There were three (<1%) deaths in the placebo group that were assessed by investigators, who were masked to study drug assignment, to be treatment-related and two (<1%) deaths in the albiglutide group. Interpretation: In patients with type 2 diabetes and cardiovascular disease, albiglutide was superior to placebo with respect to major adverse cardiovascular events. Evidence-based glucagon-like peptide 1 receptor agonists should therefore be considered as part of a comprehensive strategy to reduce the risk of cardiovascular events in patients with type 2 diabetes. Funding: GlaxoSmithKline

Using Screencasts in Computer Science Classes at a Technical University

The information technologies applications in various fields of human activity are developing exponentially now. The article considers possibility of using screencasting in a computer science course at a technical university. Screencast is a video that contains a record of actions performed on a computer with the author’s comments. The advantages and disadvantages of this technology in the learning process are considered. It is noted that the technology of on-screen video is distinguished by information richness and strong emotional effect on the student. The application of screencasting in computer science classes at the Tomsk Polytechnic University using the mathematical package MathCad, which has the means to solve all kinds of problems associated with symbolic operations, is presented. The motivation for this study is to increase the student learning process effectiveness. Therefore, the objectives of the study are: to study the possibility of screencasting in the student learning process organization, to study the possibility of using this technology during studying a computer science course, to find out how effectively this method allows to master knowledge in the relevant discipline. The results of study using this technology and the traditional method are analyzed. It is shown that the use of screencasting allows to improve the test results in comparison with the group trained by the traditional method

Scaling Law of THz Yield from Two-Color Femtosecond Filament for Fixed Pump Power

In 3D + time numerical simulations, we study the wavelength scaling law for the energy of terahertz (THz) radiation emitted from a two-color femtosecond filament, which forms during cofocusing into air the fundamental and second harmonics of the laser pulse. In our simulations, the central wavelength of the fundamental harmonic varied from 0.8 to 8 μm and the numerical aperture varied from 0.006 to 0.03. While the harmonics and supercontinuum development are not extreme, so the harmonics spectra are clearly separated, the energy of the generated THz radiation is proportional to the oscillation energy of the electrons, which grows as the squared pump wavelength, and the total number of free electrons in the filament, which decreases quasi-exponentially with the pump wavelength. As a result, the scaling law for the THz energy on the pump wavelength is nonmonotonic with the maximum at 1.6–4 μm depending on the focusing conditions

Scaling Law of THz Yield from Two-Color Femtosecond Filament for Fixed Pump Power

In 3D + time numerical simulations, we study the wavelength scaling law for the energy of terahertz (THz) radiation emitted from a two-color femtosecond filament, which forms during cofocusing into air the fundamental and second harmonics of the laser pulse. In our simulations, the central wavelength of the fundamental harmonic varied from 0.8 to 8 μm and the numerical aperture varied from 0.006 to 0.03. While the harmonics and supercontinuum development are not extreme, so the harmonics spectra are clearly separated, the energy of the generated THz radiation is proportional to the oscillation energy of the electrons, which grows as the squared pump wavelength, and the total number of free electrons in the filament, which decreases quasi-exponentially with the pump wavelength. As a result, the scaling law for the THz energy on the pump wavelength is nonmonotonic with the maximum at 1.6–4 μm depending on the focusing conditions

Obuchenie bol'nykh sakharnym diabetom: psikhologicheskiy analiz

В настоящее время во всем мире лечебно-профилактическая помощь больным сахарным диабетом (СД) оказывается преимущественно в амбулаторных условиях. Известно, что эффективность лечения больных СД в большой мере обеспечивает обучение принципам управления заболеванием. Обучение больных хроническими заболеваниями является развитой научной и практической областью медицины, регламентированной рекомендациями ВОЗ. Для обучения применяют специально разработанные структурированные программы, доказавшие свою эффективность в рамках контролируемых исследований. В деле обучения необходимо профессиональное участие психологов, и, повидимому, значительный потенциал эффективности обучения больных диабетом заключен в развитии и совершенствовании психологического подхода к этому процессу

Author's personal copy A comparison of numerical and analytical radiative-transfer solutions for plane albedo of natural waters

a b s t r a c t Several numerical and analytical solutions of the radiative transfer equation (RTE) were compared for plane albedo in a problem of solar light reflection by sea water. The study incorporated the simplest case-a semi-infinite one-dimensional plane-parallel absorbing and scattering homogeneous layer illuminated by a monodirectional light beam. Inelastic processes (such as Raman scattering and fluorescence), polarization and air-water surface refraction-reflection effects, were not considered. Algorithms were based on the invariant imbedding method and two different variants of the discrete ordinate method (DOM). Calculations were performed using parameters across all possible ranges (single-scattering albedo o 0 and refracted solar zenith angle y 1 ), but with a special emphasis on natural waters. All computations were made for two scattering phase functions, which included an almost isotropic Rayleigh phase function and strongly anisotropic double-peaked Fournier-Forand-Mobley phase function. Models were validated using quasi-single-scattering (QSSA) and exponential approximations, which represent the extreme cases of o 0 -0 and o 0 -1, respectively. All methods yielded relative differences within 1.8% for modeled natural waters. An analysis of plane albedo behavior resulted in the development of a new extended QSSA approximation, which when applied in conjunction with the extended Hapke approximation developed earlier, resulted in a maximum relative error of 2.7%. The study results demonstrated that for practical applications, the estimation of inherent optical properties from observed reflectance can best be achieved using an extended Hapke approximation

Potential energy surfaces of adsorption and migration of transition metal atoms on nanoporus materials: The case of nanoporus bigraphene and G-C3N4

Abstract First-row transition metal (TM) atoms adsorption and migration on nanoporus 2D materials like bigraphene with double vacancies and g-C3N4 as the active sites for TM nanocluster’s growth was studied within the framework of density functional theory. Both thermodynamic and kinetic aspects of composite synthesis were discussed. It was found that potential barriers of adatom’s migration from bigraphene’s outer surface to the interlayer space through the double vacancy are rather low values. High potential barriers of TM migration along the carbon plane prevents TM clusterization due to enhanced chemical activity of double vacancies which gives a possibility to capture the surface adatoms. As was shown for the monolayer graphene, the decrease of vacancies concentration reduces the barrier of adatom migration along the surface while the second graphene sheet in bigraphene stabilizes the structure. The behavior of TM-atom regarding g-CN2 and g-CN1 nanosheets was investigated. Potential energy surfaces were obtained and discussed. The migration barriers were found surmountable that means high probability of migration of TM adatoms to global minima and formation of TM vacancies. Comparison of barriers values with Boltzmann factor demonstrated that just standalone temperature fluctuations cannot initiate structural transitions. The properties of designed structures can be of interest of catalysts and biosensors for biomedical applications

Low-Frequency Content of THz Emission from Two-Color Femtosecond Filament

We experimentally investigate the low-frequency (below 1 THz) spectral content of broadband terahertz (THz) emission from two-color femtosecond filament formed by the 2.7-mJ, 40-fs, 800+400-nm pulse focused into air. For incoherent detection, we screened the Golay cell by the bandpass filters and measured the THz angular distributions at the selected frequencies ν=0.5, 1, 2 and 3 THz. The measured distributions of THz fluence were integrated over the forward hemisphere taking into account the transmittance of the filters, thus providing the estimation of spectral power at the frequencies studied. The spectral power decreases monotonically with the frequency increasing from 0.5 to 3 THz, thus showing that the maximum of THz spectrum is attained at ν≤0.5 THz. The THz waveform measured by electro-optical sampling (EOS) based on ZnTe crystal and transformed into the spectral domain shows that there exists the local maximum of the THz spectral power at ν≈1 THz. This disagrees with monotonic decrease of THz spectral power obtained from the filter-based measurements. We have introduced the correction to the spectral power reconstructed from EOS measurements. This correction takes into account different focal spot size for different THz frequencies contained in the broadband electromagnetic pulse. The corrected EOS spectral power is in semi-quantitative agreement with the one measured by a set of filters