Light-induced transmission nonlinearities in gallium selenide

The intensity of a He–Ne laser (633 nm, 5 mW) transmitted by different GaSe samples is observed to change in correlation with a Nd-yttrium–aluminum–garnet laser pulse (532 nm, 7.8 ns, 3 mJ) which excites them. Such time response has been attributed to a nonlinear optical effect, i.e., a decrease in the refractive index due to the exciton screening by the photogenerated carriers. A calculation of the absorption coefficient and refractive index at different carrier concentrations has led to a reconstruction of transmittance transients which fully agree with the experimental data at different incident intensities and [email protected] ; [email protected] ; [email protected] ; [email protected]

Photoelectrochemical behavior of the ternary heterostructured systems CdS/WO3/TiO2

In this article, we report the results of comparative studies of photoelectrochemical behavior of the binary CdS/TiO2 and WO3/TiO2 and ternary CdS/WO3/TiO2 heterostructures based on titania nanotube and planar structures. Physical–chemical characterization by XRD, XPS, and electron microscopy methods together with electrochemical impedance spectroscopy measurements confirm a successful formation of heterostructured electrodes, both nanotube-based and planar. The results of photoelectrochemical studies of the heterostructures demonstrate a significant difference in their behavior depending on the structure geometry and the character of the formed heterojunctions. It is concluded that nanotube-based heterostructure electrodes can be characterized by a stochastic set of different heterojunctions while planar systems demonstrate well-ordered heterojunctions with a strictly defined electron transfer direction. Particularly, we demonstrate the possibility of the realization of Z-scheme of photoexcitation and charge separation in ternary planar systems under visible light irradiation

Minimally Invasive Treatment of Benign Thyroid Nodules

Background. Nodular goitre is the commonest pathology of thyroid gland. According to published evidence, the endemic prevalence of iodine deficiency varies within 19–76 % population. The high rates and lack of symptoms at progressive nodules growth warrant the development of effective organ-preserving treatments. Imaging techniques for local precision targeting of individual lesions enable maximum-preserving interventions at thyroid tissue. Today’s world experience of percutaneous ethanol sclerotherapy and radiofrequency ablation is adequate. However, there exist no clear indications for sclerotherapy and radiofrequency ablation, and their consecutive use has not been assessed.Materials and methods. We analyse minimally invasive organ-preserving treatments of benign thyroid nodules (ethanol sclerotherapy, RFA) in 63 patients at the outpatient and general surgery units of BSMU Clinic and MEGI Medical Centre, Ufa, during February 2019 — December 2020.Results and discussion. Ethanol sclerotherapy was highly effective in 46.5 % patients, as evident from discontinued nodule’s blood supply in CDI and B-mode ultrasound, which remained stable in 10.5 % and restored after 3–4 weeks in 25 % patients. Sclerotherapy in colloid goitre was efficient only in 37.5 % patients. Ethanol sclerotherapy was RFA-followed in 25.4 % patients. RFA was favoured at a low-effective sclerotherapy providing for a weak positive dynamics of nodule size, local parietal blood flow preservation and intranodular vessels recanalisation at re-examination.Conclusion. Sclerotherapy was high-effective in cystic nodules. Radiofrequency ablation can be considered most adequate for treating solid nodules. RFA-followed sclerotherapy is a rational choice in treatment of large cystic nodules (>5 cm3 )

Мини-инвазивные способы лечения доброкачественных узлов щитовидной железы

Background. Nodular goitre is the commonest pathology of thyroid gland. According to published evidence, the endemic prevalence of iodine deficiency varies within 19–76 % population. The high rates and lack of symptoms at progressive nodules growth warrant the development of effective organ-preserving treatments. Imaging techniques for local precision targeting of individual lesions enable maximum-preserving interventions at thyroid tissue. Today’s world experience of percutaneous ethanol sclerotherapy and radiofrequency ablation is adequate. However, there exist no clear indications for sclerotherapy and radiofrequency ablation, and their consecutive use has not been assessed.Materials and methods. We analyse minimally invasive organ-preserving treatments of benign thyroid nodules (ethanol sclerotherapy, RFA) in 63 patients at the outpatient and general surgery units of BSMU Clinic and MEGI Medical Centre, Ufa, during February 2019 — December 2020.Results and discussion. Ethanol sclerotherapy was highly effective in 46.5 % patients, as evident from discontinued nodule’s blood supply in CDI and B-mode ultrasound, which remained stable in 10.5 % and restored after 3–4 weeks in 25 % patients. Sclerotherapy in colloid goitre was efficient only in 37.5 % patients. Ethanol sclerotherapy was RFA-followed in 25.4 % patients. RFA was favoured at a low-effective sclerotherapy providing for a weak positive dynamics of nodule size, local parietal blood flow preservation and intranodular vessels recanalisation at re-examination.Conclusion. Sclerotherapy was high-effective in cystic nodules. Radiofrequency ablation can be considered most adequate for treating solid nodules. RFA-followed sclerotherapy is a rational choice in treatment of large cystic nodules (>5 cm3 ). Введение. Самой распространенной патологией щитовидной железы является узловой зоб. Встречаемость йододефицита в  эндемических регионах варьирует, по литературным данным, от 19  до 76  % населения. Высокая распространенность, бессимптомное течение с прогрессирующим ростом узлов диктуют необходимость выработки эффективных органосохраняющих методов лечения. Имея визуализирующие способы локального прецизионного воздействия на отдельные патологически измененные структуры, можно выполнять вмешательства с максимальным сохранением неизмененной ткани щитовидной железы. На сегодня в мире уже накоплен достаточный опыт применения чрескожной склеротерапии этанолом и радиочастотной абляции (РЧА). Однако не разработаны четкие показания к применению склеротерапии и радиочастотной абляции и не оценена возможность последовательного их применения.Материалы и методы. В работе представлен анализ лечения доброкачественных узлов щитовидной железы мини-инвазивными органосохраняющими методами (этаноловая склеротерапия, РЧА) у 63 пациентов, проведенными на базе амбулаторного отделения и отделения общей хирургии Клиники Башкирского государственного медицинского института и медицинского центра «МЕГИ», г. Уфа, в период с февраля 2019 до декабря 2020 г.Результаты и обсуждение. Применение этаноловой склеротерапии было высокоэффективным у  46,5  % пациентов, оценку проводили по нарушению питания узла в виде исчезновения кровотока при УЗД исследовании в режиме ЦДК и B-flow, которое отмечалось в 10,5 % случаев — стабильное и в 25 % отмечено восстановление кровотока спустя 3–4 недели. При склеротерапии узлов с признаками организации коллоида эффективность отмечена только у 37,5 % пациентов. У 25,4 % исследуемых после этаноловой склеротерапии была проведена последующая РЧА. Решение в пользу РЧА было принято при малоэффективном курсе склеротерапии в виде слабой положительной динамики размеров узла, сохранения пристеночных локусов кровотока и реканализации внутринодулярных сосудов при повторном осмотре.Заключение. Высокая эффективность склерозирующей терапии отмечалась при кистозном характере узла. В лечении узлов, имеющих солидный характер, лучшим методом следует признать радиочастотную деструкцию. При лечении кистозно-трансформированных узлов больших размеров (более 5 см3 ) рационально проведение сеансов склеротерапии перед РЧА.

Combined Effects of Screening and Band Gap Renormalization on the Energy of Optical Transitions in ZnO and GaN

The energy positions of the optical transitions in both GaN and ZnO were investigated when the samples were excited simultaneously with a HeCd laser and an Ar+ ion laser. The increased number of free electrons excited by the Ar+ ion laser will effectively screen both the free exciton and bound exciton transitions, resulting in a blueshift. The increased number of free electrons also produces many-body effects, which lead to a reduction of the band gap energy and thus a redshift. The resultant of screening and renormalization results in a redshift of the optical transitions in ZnO but a nearly vanishing shift in GaN

Robot-assisted removal of the orbital tumor (from practice)

The implementation of robotic surgery, in particular the da Vinci surgical system, is one of the biggest breakthroughs in surgery since the invention of anesthesia, and represents the most significant achievement in minimally invasive surgery of this decade. If the use of the da Vinchi robotic system in pelvic surgery has long been the gold standard, the use of this system in surgery of the base of the skull and sinuses is quite rare and is currently more experimental. Due to the lack of description in the domestic and foreign literature, it seems interesting to us to demonstrate the clinical observation of a patient with an orbital tumor