Influence of retardation effects on 2D magnetoplasmon spectrum

Within dissipationless limit the magnetic field dependence of magnetoplasmon spectrum for unbounded 2DEG system found to intersect the cyclotron resonance line, and, then approaches the frequency given by light dispersion relation. Recent experiments done for macroscopic disc-shape 2DEG systems confirm theory expectations.Comment: 2 pages,2 figure

Nomenclatural standards and genetic passports of potato cultivars bred by the Omsk Agrarian Research Center

In accordance with the International Code of Nomenclature for Cultivated Plants, five nomenclature standards were prepared for five potato сultivars* bred in the Omsk Agrarian Research Center: ‘Alena’, ‘Bylina Sibiri’, ‘Večernij Omsk’, ‘Triumf’, ‘Hozâûška’. Genetic passport of these five cultivars were carried out according to the new integrated strategy developed at VIR. According to the strategy, the plant material donated by the author of the cultivars to the VIR Herbarium was used for molecular genotyping. Genetic passports included data of allelic composition of eight chromosome specific microsatellite loci, markers of different types of organelle DNA, as well as data about diagnostic fragments of 15 markers of 11 R-genes conferring resistance to the most dangerous diseases and pests of potato: late blight, nematodes, potato X and Y viruses. Data from the developed genetic passports of five Omsk cultivars were compared to the results of genotyping of samples of the same cultivars obtained from different sources. Based on the analysis of pedigrees and genetic passports of these five cultivars we established the origin of their resistance to harmful organisms

Influence of anionic surfactant on stability of nanoparticles in aqueous solutions

Dispersion and aggregation of nanoparticles in aqueous solutions are important factors for safe and effective application of nanoparticles, for instance, in the oil industry. As conventional oil reserves are depleted, it is necessary to advance chemical enhanced oil recovery (cEOR) techniques to develop unconventional oil reservoirs. Nanoparticles modified by surfactants can be a promising reagent in cEOR. These nanomaterials can reduce interfacial tension and change the wettability of reservoir rock, which leads to an increase in oil recovery. However, the application of nanoparticles is limited by their substantial aggregation in aqueous solutions. The purpose of this work is to select nanoparticles for obtaining stable sols in water in the presence of an anionic surfactant and to optimize the conditions (pH) for further modifying the nanoparticles with the anionic surfactant. Sodium dodecyl sulfate (SDS) is used as an anionic surfactant. The aggregation of oxide and carbon nanoparticles in water and anionic surfactant solutions was studied by laser diffraction, dynamic and electrophoretic light scattering methods. Most of the studied nanoparticles in water form aggregates with bi-, three- and polymodal particle size distributions. TiO2 nanoparticles obtained by plasma dynamic synthesis form the most stable sols in anionic surfactant solutions. The range of 5–7 pH is defined as optimal for their modification with surfactants. The stability of carbon nanoparticles in aqueous solutions increases significantly in the presence of a surfactant. The obtained results form the basis for further research on the modification of marked nanoparticles in surfactant solutions

Ротационная борона для грядовых обработок посадок картофеля

It was established that quality pre-emergence cultivation of potato ridges depends on possibility of surface copying by working tools of a rotary harrow because of their vibrations. Rotary harrow design having damping devices and V-shaped spike tooth was suggested. Energy consumption evaluation depending on its speed, soil drag, operating modes and design parameters of working tools were researched. The optimal chain changing tension range was founded (100-120 H). Thus, the specific traction resistance of the newly developed harrow equaled 200-210 H/m, or 20 percent lower than that of a serial one. Data of field experiments characterizing influence of a harrow on quality of ridge cultivation and yield of potatoes were presented. It was showed that it is possible to create more favorable conditions for development and growth of potato due to use new harrow. As result potatoes yield increased by 1.2 -1.5 t/ha, or 4-6 percent. Fuel savings amounted to 12 percent.Установили, что качество довсходовой обработки гряд зависит от возможности копирования поверхности рабочими органами ротационной бороны вследствие создания ими поперечных колебаний. Предложили конструкцию ротационной бороны с демпфирующими устройствами и зубом V-образной формы. Исследовали зависимость энергоемкости бороны от скорости ее движения, сопротивления почвы, режимов работы и конструктивных параметров рабочих органов. Выявили оптимальный диапазон натяжения цепи бороны (100-120 Н). При этом удельное тяговое сопротивление разработанной бороны составило 200-210 Н/м, или на 20 процентов ниже, чем у серийной. Привели данные полевых опытов, характеризующие влияние бороны на качество обработки гряды и урожайность картофеля. Показали возможность создания более благоприятных условий для развития и роста картофеля с помощью использования новой бороны, что повысило урожайность, в сравнении с серийной бороной, на 1,2-1,5 т/га, или на 4-6 процентов. Экономия топлива составила 12 процентов

Роль 3D-моделирования в хирургии поджелудочной железы: обзор

INTRODUCTION: Surgical interventions on the pancreas are technically complex and are accompanied by a fairly large number of complications, which is largely due to the variant anatomy of the pancreas.OBJECTIVE: The aim of this paper is to evaluate the possibilities of 3D modeling in the surgical treatment of pancreatic diseases according to the literature.MATERIALS AND METHODS: Literature searched in Russian and English for the period from 2017 to 2022 in Medline/PubMed, RSCI/Elibrary, CyberLeninka, Google Scholar databases. The search was conducted on the keywords: pancreas, chronic pancreatitis, pancreatic cancer, pancreatic resection, computed tomography, 3-D modeling, 3-D reconstruction, surgical planning, surgical intervention, pancreas, chronic pancreatitis, pancreas cancer, pancreatectomy, computed tomography, 3-D modeling, 3D reconstruction, surgical planning.RESULTS: 49 publications on various aspects of the use of 3D modeling in pancreatic surgery were included in the final analysis. The diagnostic value of building three-dimensional models in assessing the resectability of pancreatic tumors, identifying individual topographic and anatomical features of the pancreatobiliary zone, which should be taken into account during surgery to avoid intra- and postoperative complications, is shown. Examples of a description based on 3D modeling of rare vascular anomalies and cysts that are not visualized according to standard computed tomography in patients who are scheduled for pancreatic surgery are presented. The importance of postoperative 3D modeling of the pancreas for assessing the adequacy of the surgical intervention and early detection of possible complications of the operation is indicated.CONCLUSION: 3D modeling is an innovative and promising diagnostic method that allows increasing the information content of standard computed tomography in pancreatic surgery. 3D models make it possible to select patients for pancreatic resection and substantiate the most optimal surgical strategy. In the future, we should expect an improvement in the results of surgical treatment of pancreatic tumors and complicated pancreatitis.ВВЕДЕНИЕ: Хирургические вмешательства на поджелудочной железе отличаются технической сложностью и сопровождаются достаточно большим количеством осложнений, что во многом обусловлено вариантой анатомией поджелудочной железы.ЦЕЛЬ: Оценить возможности 3D-моделирования при хирургическом лечении заболеваний поджелудочной железы по данным литературы.МАТЕРИАЛЫ И МЕТОДЫ: Выполнен поиск литературы на русском и английском языках за период с 2017 по 2022 гг. в базах данных Medline/PubMed, РИНЦ/Elibrary, КиберЛенинка, Google Scholar по ключевым словам: поджелудочная железа, хронический панкреатит, рак поджелудочной железы, резекция поджелудочной железы, компьютерная томография, 3D-моделирование, 3D-реконструкция, хирургическое планирование, хирургическое вмешательство, pancreas, chronic pancreatitis, pancreas cancer, pancreatectomy, computed tomography, 3D modeling, 3D reconstruction, surgical planning.РЕЗУЛЬТАТЫ: В окончательный анализ были включены 49 публикаций, посвященных различным аспектам применения 3D-моделирования в хирургии поджелудочной железы. Показана диагностическая ценность построения трехмерных моделей в оценке резектабельности опухолей поджелудочной железы, выявлении индивидуальных топографо-анатомических особенностей панкреатобилиарной зоны, которые должны учитываться во время операции во избежание интра- и послеоперационных осложнений. Представлены примеры описания на основе 3D-моделирования редких сосудистых аномалий и кист, не визуализированных по данным стандартной компьютерной томографии, у пациентов, которым планируется операция на поджелудочной железе. Обозначена значимость послеоперационного 3D-моделирования поджелудочной железы для оценки адекватности проведенного хирургического вмешательства и раннего выявления возможных осложнений операции.ЗАКЛЮЧЕНИЕ: 3D-моделирование является инновационным и перспективным методом диагностики, который позволяет повысить информативность стандартной компьютерной томографии в хирургии поджелудочной железы. 3D-модели позволяют отобрать пациентов для резекции поджелудочной железы и обосновать оптимальную хирургическую стратегию. В перспективе следует ожидать улучшение результатов хирургического лечения опухолей поджелудочной железы и осложненного панкреатит

Measuring thermoelectric transport properties of materials

In this review we discuss considerations regarding the common techniques used for measuring thermoelectric transport properties necessary for calculating the thermoelectric figure of merit, zT. Advice for improving the data quality in Seebeck coefficient, electrical resistivity, and thermal conductivity (from flash diffusivity and heat capacity) measurements are given together with methods for identifying possible erroneous data. Measurement of the Hall coefficient and calculation of the charge carrier concentration and mobility is also included due to its importance for understanding materials. It is not intended to be a complete record or comparison of all the different techniques employed in thermoelectrics. Rather, by providing an overview of common techniques and their inherent difficulties it is an aid to new researchers or students in the field. The focus is mainly on high temperature measurements but low temperature techniques are also briefly discussed

PROSPECTS FOR LOWERING DOSES DURING PREVENTIVE DIGITAL CHEST RADIOGRAPHY

Objective: to search for the possibility of lowering a dose burden on a patient during preventive chest radiography.Material and methods. The investigation was carried out in two hospitals (City Mariinsky Hospital, Saint Petersburg, Russia) and (Skane University Hospital, Malm ° ö, Sweden) in 2013–2015. The existing protocols for this type of investigation were corrected by changing the anode voltage, the thickness of complete filtration, and the refusal to use a raster to determine the optimal dose/image quality ratio.Results. The investigation showed the possibility of reducing the values of the products of the dose per area (PDA) by 47% and lowering the effective dose (ED) by 33%, by increasing the tube voltage (up to 125 or 150 kV) and decreasing the thickness of full filtration of direct beam radiation (to 3 mm Al). The refusal to use a raster could further reduce the value of PDA and ED to 75%.Conclusion. Comparison of the dose values of Russian and Swedish X-ray apparatuses showed that the absolute values of PDP and ED are 10 times lower for Swedish devices in the same modes of chest radiography. This fact can be explained by the use of various image receivers and automatic exposure control settings

Results of the clinical evaluation of the low-dose protocols of the digital linear tomography of the chest

High levels of tuberculosis morbidity in the Russian Federation lead to the extensive use of X-ray diagnostics for the tuberculosis screening and assessment of the effectiveness of treatment. Digital radiography and computed tomography are traditionally used for the diagnostics of tuberculosis. These methods are associated with significant drawbacks: low specificity for radiography, high costs per examination, significant patient doses, and limited availability for computed tomography. As an additional method for the assessment of the effectiveness of the tuberculosis treatment it is possible to use linear tomography performed on the digital X-ray units. The aim of the current study was to evaluate the possibility of utilization of the digital linear tomography for the control of the effectiveness of tuberculosis treatment in a dedicated antitubercular medical facility. The study was divided in two stages. The first stage was aimed at the assessment of the diagnostic image quality of the digital linear tomograms obtained using the previously developed low-dose imaging protocols. Image quality assessment was performed using an anthropomorphic chest phantom and dedicated imitators of the lung lesions. Image quality was assessed by the experts (radiologists) based on the developed image quality criteria. Results of the first stage of the study indicate that all low-dose protocols allow obtaining images with at least acceptable image quality. Hence it was possible to propose low-dose protocols for clinical evaluations. The second stage of the study was performed as a prospective cohort survey aimed at the evaluation of the structure of X-ray examinations, patient doses and clinical image quality of the digital linear tomograms in antitubercular early treatment center. The cohort survey included two patient samples, uniform by age and gender composition, anthropometric characteristics and structure of diagnosis. One of the samples was imaged using standard (vendor) digital linear protocols, other – using the proposed low-dose protocols. Dose data collection (measurement of dose-area product and subsequent calculation of effective dose) and expert image quality assessment was performed for each patient. The results of the second stage of the study indicate that the use of the low-dose protocols allow reducing the patient effective doses per examination up to a factor of 6–8 (0.56 – 5.9 mSv for standard protocols; 0.2 – 1.15 mSv for low-dose protocols) due to the reduction in tube current-time product (126 mean mAs and 11 mean mAs, respectively). The dose reduction is accompanied by the reduction in the image quality of the linear tomograms (from “excellent” or “good” for standard protocols to “acceptable” for low-dose protocols). However, that dose not hinder the conclusion decision and identification of pathologies. Results of the study indicate that digital linear tomography can be used for the evaluation of the dynamics of the pathological process in the lungs with the previously defined localization of the pathology. The presented low-dose protocols were implemented into radiological practice of the antitubercular early treatment center. Currently, the proposed low-dose protocols are under evaluation for the large-scale study on the base of general practice hospital