Micro-holographic methods for sub-micrometer grating fabrication in fused silica with UV femtosecond laser

The optical layouts incorporating binary phase diffractive grating and a standard micro-objective were used for femtosecond microfabrication of periodical structures in fused silica. Two beams, generated in Talbot type interferometer, interfered on a surface and in the bulk of the sample. The method suggested allows better control over the transverse size of the grating pitch, and thus control the reflection strength of the waveguide or fibre grating. We present the examples of direct inscription of the sub-micrometer periodical structures using a 267 nm femtosecond laser radiation

Point-by-point inscription of 250-nm-period structure in bulk fused silica by tightly-focused femtosecond UV pulses: experiment and numerical modeling

By conducting point-by-point inscription in a continuously moving slab of a pure fused silica at the optimal depth (170 μm depth below the surface), we have fabricated a 250-nm-period nanostructure with 30 nJ, 300 fs, 1 kHz pulses from frequency-tripled Ti:sapphire laser. This is the smallest value for the inscribed period yet reported, and has been achieved with radical improvement in the quality of the inscribed nanostructures in comparison with previous reports. The performed numerical modeling confirms the obtained experimental results

β\beta-BaB2_2O4_4 deep UV monolithic walk-off compensating tandem

The generation of watt-level cw narrow-linewidth sources at specific deep UV wavelengths corresponding to atomic cooling transitions usually employs external cavity-enhanced second-harmonic generation (SHG) of moderate-power visible lasers in birefringent materials. In this work, we investigate a novel approach to cw deep-UV generation by employing the low-loss BBO in a monolithic walkoff-compensating structure [Zondy {\it{et al}}, J. Opt. Soc. Am. B {\bf{20}} (2003) 1675] to simultaneously enhance the effective nonlinear coefficient while minimizing the UV beam ellipticity under tight focusing. As a preliminary step to cavity-enhanced operation, and in order to apprehend the design difficulties stemming from the extremely low acceptance angle of BBO, we investigate and analyze the single-pass performance of a $L_c=8$mm monolithic walk-off compensating structure made of 2 optically-contacted BBO plates cut for type-I critically phase-matched SHG of a cw $\lambda=570.4$nm dye laser. As compared with a bulk crystal of identical length, a sharp UV efficiency enhancement factor of 1.65 has been evidenced with the tandem structure, but at $\sim-1$nm from the targeted fundamental wavelength, highlighting the sensitivity of this technique when applied to a highly birefringent material such as BBO. Solutions to angle cut residual errors are identified so as to match accurately more complex periodic-tandem structure performance to any target UV wavelength, opening the prospect for high-power, good beam quality deep UV cw laser sources for atom cooling and trapping.Comment: 21 pages, 8 figures, to appear in Opt. Commu

Chronic constipation among medical students

In the course of the work, the results of a questionnaire survey of 81 students of a medical university aged 18 to 26 years were analyzed. Constipation was detected in 8 (7.5%) respondents, among whom women predominated (7 people, or 87.5%). Regularity of food intake, daily intake of dietary fiber and adequate water intake did not have a statistically significant difference in persons with and without constipation.В ходе работы были проанализированы результаты анкетирования 81 студента медицинского университета в возрасте от 18 до 26 лет. Запоры выявлены у 8 (7,5%) респондентов, среди которых преобладали женщины (7 человек, или 87,5%). Регулярность приема пищи, ежедневное употребление пищевой клетчатки и достаточное потребление воды не имели статистической достоверной разницы у лиц, имеющих запоры и без ни

Hygienic assessment of radiation safety indicators in the educational case of USMA

The article presents the results of the sanitary-hygienic assessment of the radiation situation in the educational case of USMA; measures for the organization of radiation safety under the influence of natural sources of ionizing radiation in the premises of residential and public buildings are presented.В статье изложены результаты санитарно-гигиенической оценки радиационной обстановки учебного корпуса УГМУ; представлены меры радиационной безопасности при воздействии природных источников ионизирующего излучения в помещениях жилых и общественных зданий

A 750 mW, continuous-wave, solid-state laser source at 313 nm for cooling and manipulating trapped 9Be+ ions

We present a solid-state laser system that generates 750 mW of continuous-wave single-frequency output at 313 nm. Sum-frequency generation with fiber lasers at 1550 nm and 1051 nm produces up to 2 W at 626 nm. This visible light is then converted to UV by cavity-enhanced second-harmonic generation. The laser output can be tuned over a 495 GHz range, which includes the 9Be+ laser cooling and repumping transitions. This is the first report of a narrow-linewidth laser system with sufficient power to perform fault-tolerant quantum-gate operations with trapped 9Be+ ions by use of stimulated Raman transitions.Comment: 9 pages, 4 figure

Analysis of adherence to the measures of non-specific prevention of coronavirus infection by students of the Ural State Medical University based on a questionnaire

The article analyzes the results of a survey of students of the Faculty of Medicine of the Ural State Medical University on the topic of adherence to non-specific prophylaxis of coronavirus infection.В статье проанализированы результаты анкетирования студентов медико-профилактического факультета Уральского государственного медицинского университета на тему приверженности неспецифической профилактики коронавирусной инфекции

Гемодинамические нарушения в фетоплацентарном комплексе при инфицировании вирусом гриппа

Мета роботи – ультразвукове дослідження фетоплацентарного комплексу у вагітних із перенесеною під час вагітності чи наявною грипозною інфекцією. Матеріали та методи. Обстежили 102 вагітні. Здійснена ультразвукова діагностика стану фетоплацентарного комплексу, матково-плацентарного, плодово-плацентарного кровотоку методом доплерографії. Результати. У вагітних із перенесеною під час вагітності або наявною грипозною інфекцією в І триместрі локальний гіпертонус виявлений у 60,8 % вагітних, часткове відшарування хоріону – у 7,8 %, локалізація плодового яйця в нижніх відділах матки – у 48,0 %. У ІІ триместрі загальний гіпертонус виявлений у 71,6 % спостережень, низька плацентація – у 58,8 %, плацентарна дисфункція – у 100 %, передчасне дозрівання плаценти – у 43,1 %, гіпотрофія, гіпертрофія плаценти – у 54,9 %; 41,2 % відповідно, багатоводдя – у 32,4 %, маловоддя – у 16,7 %, часткове відшарування плаценти – у 24,5 %, загроза пізнього викидня – у 31,4 %, загроза передчасних пологів – у 36,3 %, синдром затримки росту плода – в 52,9 %. У ІІІ триместрі загальний гіпертонус виявлений у 72,5 % спостережень, часткове відшарування плаценти – у 27,5 %, низька плацентація – в 48,0 %, плацентарна дисфункція – у 100 %, передчасне дозрівання плаценти та гіпотрофія плаценти – у 45,1 % та 56,9 % відповідно, гіпертрофія – у 44,1 %, багатоводдя – у 37,3 %, маловоддя – у 17,6 %, синдром затримки росту плода – у 59,8 %. Порушення матково-плацентарного кровотоку діагностовані в 52,9 %, плодово-плацентарного кровотоку – у 70,6 %, гострий дистрес плода – у 29,4 %, хронічний дистрес плода – в 70,6 %. Висновки. Ультразвукове дослідження фетоплацентарного комплексу у вагітних із перенесеною під час вагітності або наявною грипозною інфекцією показало, що перебіг вагітності супроводжується високою частотою акушерських і перинатальних ускладнень та дає змогу своєчасно виявити наявність загрози їхньому розвитку.The aim of the work was to carry out of ultrasound examination of a feto-placental complex in pregnant women who were infected with influenza or infected with influenza at the time of examination. Materials and Methods. 102 pregnant women were examined. Ultrasound diagnostics of a feto-placental complex, utero-placental, feto-placental blood circulation state has been done by the method dopplerography. Results. In the first trimester the local hypertonia was revealed in 60.8 % of pregnant women, partial detachment of chorion – in 7.8 %, ovum localization in the bottom departments of uterus – in 48.0 %. In second trimester the general hypertonia was revealed in 71.6 % of monitoring, low placentation – in 58.8 %, placental dysfunction – in 100 %, premature maturation of placenta – in 43.1 %hypotrophy and hypertrophy of placenta – in 54.9 % and 41.2 % respectively; hydramnion and oligoamnios – in 32.4 % and 16.7 % respectively, partial placental abruption – in 24.5 %, risk of late-term abortion – in 31.4 %, threat of preterm birth – in 36.3 %, fetal growth retardation syndrome – in 52.9 %. In the third trimester the general hypertonia was revealed in 72.5 % of monitoring, partial placental abruption – in 27.5 %, low placentation – in 48.0 %, placental dysfunction – in 100 %, premature maturation of placenta and hypotrophy of placenta – in 45.1 % and 56.9 % respectively, hypertrophy of placenta – in 44.1 %, hydramnion and oligoamnios – in 37.3 % and 17.6 %, fetal growth retardation syndrome – in 59.8 %. Disturbance of utero-placental blood circulation was diagnosed in 52.9 % of cases, feto-placental blood circulation – in 70.6 %, acute fetal distress – in 29.4 %, chronic fetal distress – in 70.6 %. Conclusions. Ultrasound examination of feto-placental complex in pregnant women who were infected with influenza or infected with influenza at the time of examination has shown that the pregnancy was accompanied by high frequency of obstetric and perinatal complications. This method permits to reveal the risk of complications development timely