Single-Crystal Organic Field Effect Transistors with the Hole Mobility ~ 8 cm2/Vs

We report on the fabrication and characterization of single-crystal organic p-type field-effect transistors (OFETs) with the field-effect hole mobility mu \~ 8 cm2/Vs, substantially higher than that observed in thin-film OFETs. The single-crystal devices compare favorably with thin-film OFETs not only in this respect: the mobility for the single-crystal devices is nearly independent of the gate voltage and the field effect onset is very sharp. Subthreshold slope as small as S = 0.85 V/decade has been observed for a gate insulator capacitance Ci = 2 +- 0.2 nF/cm2. This corresponds to the intrinsic subthreshold slope Si = SCi at least one order of magnitude smaller than that for the best thin-film OFETs and amorphous hydrogenated silicon (a-Si:H) devices

Diverticular disease of the sigmoid colon, complicated by a tubular intestinal fistula of the anterior abdominal wall and cicatricial stricture of the sigmoid colon (case report)

Aim of the study was to consider a clinical example of diverticular disease of the sigmoid colon, complicated by a tubular intestinal fistula of the anterior abdominal wall and cicatricial stricture of the sigmoid colon. Material and methods. Patient B., 76 years old, was admitted to the proctology department with complaints of the presence of a fistula with purulent discharge in the area of the surgical scar. Preoperative examination with MRI, colonoscopy, fistulography revealed diverticular disease of the sigmoid colon, complicated by a tubular intestinal fistula of the anterior abdominalwall and stricture of the sigmoid colon at the level of the internal opening of the fistula. Results. The operation was performed in the following volume - excision of the fistula, resection of the sigmoid colon bearing the fistula, with endto-end anastomosis in the area without diverticula

Инновационные Технологии Взаимодействия Преподавателей и Студентов в Образовательном Процессе Вуза

Based on the analysis of scientific literature and experience, the article discusses the strategic goals of developing innovative education in Russia and modern interactive technologies of interaction between teachers and students in the educational process of the university. The authors consider the leading methodological approaches (humanistic, system-activity, competence-developing, creative, technological) and methods for studying the problem of interaction between teachers and students in the holistic educational process of the university (design, simulation, monitoring, experiment). The main content of the article is devoted to the characteristics of the theory of interaction of activity subjects and practical experience of the departments of the universities of the Russian Federation. On the basis of the conceptual apparatus, the authors analyze the essence of cooperation, interaction and innovative technologies, describe their use in teaching and educating students (characteristics of the use of innovative technologies and practical recommendations for their use. It is proved that the level of university teachers’ professionalism and mastery depends on the development of their technological competence and active interaction with students and colleagues of the university departments. The experience of designing and using interactive technologies of interaction of activity subjects can be used in the educational process of the universities.Basado en el análisis de la literatura científica y la experiencia, el artículo analiza los objetivos estratégicos del desarrollo de la educación innovadora en Rusia y las modernas tecnologías interactivas de interacción entre profesores y estudiantes en el proceso educativo de la universidad. Los autores consideran los principales enfoques metodológicos (humanísticos, de actividad del sistema, de desarrollo de competencias, creativos, tecnológicos) y los métodos para estudiar el problema de la interacción entre profesores y estudiantes en el proceso educativo holístico de la universidad (diseño, simulación, monitoreo, experimentación). El contenido principal del artículo está dedicado a las características de la teoría de la interacción de los temas de actividad y la experiencia práctica de los departamentos de las universidades de la Federación Rusa. Sobre la base del aparato conceptual, los autores analizan la esencia de la cooperación, la interacción y las tecnologías innovadoras, describen su uso en la enseñanza y la educación de los estudiantes (características del uso de tecnologías innovadoras y recomendaciones prácticas para su uso. Está comprobado que el nivel El profesionalismo y la maestría de los docentes universitarios depende del desarrollo de su competencia tecnológica y de la interacción activa con estudiantes y colegas de los departamentos universitarios. La experiencia de diseñar y utilizar tecnologías interactivas de interacción de temas de actividad se puede utilizar en el proceso educativo de las universidades.В статье на основе анализа научной литературы и опыта рассматриваются стратегические цели развития инновационного образования в России и современные интерактивные технологии взаимодействия преподавателей и студентов в образовательном процессе вуза. В последующих разделах статьи раскрываются ведущие методологические подходы (гуманистический, системно-деятельностный, компетентностно-развивающий, креативный, технологический) и методы исследования проблемы взаимодействия преподавателей и студентов в целостном педагогическом процессе вуза (проектирование, моделирование, мониторинг, эксперимент). Основное содержание статьи представлено в характеристиках теории взаимодействия субъектов деятельности и практическом опыте кафедр вузов Российских Федерации. На основе понятийного аппарата раскрывается сущность сотрудничества, взаимодействия и инновационных технологий, их использования в обучении и воспитании студентов (признаки использования инновационных технологий и практические рекомендации их применения). Доказано, что уровень профессионализма и мастерства преподавателя вуза зависит от развития его технологической компетентности и от активного взаимодействия со студентами и коллегами кафедр вуза. Опыт проектирования и использования интерактивных технологий взаимодействия субъектов может быть использован в образовательном процессе вуза

The Multisensor Array Based on Grown-On-Chip Zinc Oxide Nanorod Network for Selective Discrimination of Alcohol Vapors at Sub-ppm Range

We discuss the fabrication of gas-analytical multisensor arrays based on ZnO nanorods grown via a hydrothermal route directly on a multielectrode chip. The protocol to deposit the nanorods over the chip includes the primary formation of ZnO nano-clusters over the surface and secondly the oxide hydrothermal growth in a solution that facilitates the appearance of ZnO nanorods in the high aspect ratio which comprise a network. We have tested the proof-of-concept prototype of the ZnO nanorod network-based chip heated up to 400 °C versus three alcohol vapors, ethanol, isopropanol and butanol, at approx. 0.2–5 ppm concentrations when mixed with dry air. The results indicate that the developed chip is highly sensitive to these analytes with a detection limit down to the sub-ppm range. Due to the pristine differences in ZnO nanorod network density the chip yields a vector signal which enables the discrimination of various alcohols at a reasonable degree via processing by linear discriminant analysis even at a sub-ppm concentration range suitable for practical applications

EVALUATION OF THE EFFECTIVENESS OF RING THERMAL INSULATION FOR PROTECTING A PIPELINE FROM THE HEAVING SOIL

Areas with heaving soil are one of the most complex hindrance for the design and construction of underground pipelines. Inhomogeneity of the geological structure of the base leads to irregular uplifts of soil and pipelines. At least these processes reduce the actual service life. In the worst case, frost heave can cause emergency depressurization, oil or oil products spill and natural gas emission 'into the atmosphere. At the present time, a quantitative evaluation of the of frost heaving dynamic and designing of the protection systems has low accuracy that is confirmed by a numerous accidents occurring on the pipelines every year. To investigate the interaction of pipelines with the heaving soil and the engineering protection system the authors have developed and for the first time ever applied in practice a numerical investigation procedure that allows calculating the stressstrain state of a pipeline taking into account the dynamics of heat and mass transfer and stress-strain state of the soil. The results of the article show the boundaries of applicability of ring thermal insulation for the pipeline in concrete geological conditions. Additionally it was found that in the short sections of frost heaving (length about 3 m) additional stresses from bending are 2.2 times more than in long sections (length 20 m and more). Since the exact location of heaving soil boundary is usually unknown, engineering protection must overlay a dangerous area with a significant margin on both sides to exclude unprotected sections up to 3 m in length

Physico-mechanical properties of the sinter of various chemical composition

The paper includes data on the physico-mechanical properties of sinter of various origins including density (bulk, average, and true), porosity (open and total), critical angle of repose, internal and external angles of repose measured on dropping the material down onto a horizontal surface from a steel sheet inclined by 40 , 60 , and 80 to the horizon, angle of external friction on the steel surface, the strength properties of the sinter in a cold state and after reduction at a temperature of 500 C. The investigated sinter had the following characteristics: an average density of 3.20-3.30 g/cm3; a true density of 4.43-4.57 g/cm3; an external angle of repose of 20.5-32.3 deg; a bulk porosity of 0.46-0.50 m3/m3; a degree of reduction by hydrogen at 500 C of 3.3-4.8%. It demonstrated the following strength characteristics in the cold state: IR+5 = 92.0%, D0.5-5 = 5.5%, A-0.5 = 2.5%. The strength characteristics after low-temperature reduction in hydrogen atmosphere were as follows: IR+5 = 29.80 %; D0.5-5 = 57.6 %; A-0.5 = 12.6 %. © Published under licence by IOP Publishing Ltd

The UV Effect on the Chemiresistive Response of ZnO Nanostructures to Isopropanol and Benzene at PPM Concentrations in Mixture with Dry and Wet Air

Towards the development of low-power miniature gas detectors, there is a high interest in the research of light-activated metal oxide gas sensors capable to operate at room temperature (RT). Herein, we study ZnO nanostructures grown by the electrochemical deposition method over Si/SiO$_{2}$ substrates equipped by multiple Pt electrodes to serve as on-chip gas monitors and thoroughly estimate its chemiresistive performance upon exposing to two model VOCs, isopropanol and benzene, in a wide operating temperature range, from RT to 350 °C, and LED-powered UV illumination, 380 nm wavelength; the dry air and humid-enriched, 50 rel. %, air are employed as a background. We show that the UV activation allows one to get a distinctive chemiresistive signal of the ZnO sensor to isopropanol at RT regardless of the interfering presence of H$_{2}$O vapors. On the contrary, the benzene vapors do not react with UV-illuminated ZnO at RT under dry air while the humidity’s appearance gives an opportunity to detect this gas. Still, both VOCs are well detected by the ZnO sensor under heating at a 200–350 °C range independently on additional UV exciting. We employ quantum chemical calculations to explain the differences between these two VOCs’ interactions with ZnO surface by a remarkable distinction of the binding energies characterizing single molecules, which is −0.44 eV in the case of isopropanol and −3.67 eV in the case of benzene. The full covering of a ZnO supercell by H$_{2}$O molecules taken for the effect’s estimation shifts the binding energies to −0.50 eV and −0.72 eV, respectively. This theory insight supports the experimental observation that benzene could not react with ZnO surface at RT under employed LED UV without humidity’s presence, indifference to isopropanol

Changes in somatosensory evoked potentials in rats following transient cerebral ischemia

Background. Cerebral ischemia induced by transient middle cerebral artery occlusion is one of the most popular ischemic stroke models used to evaluate drug candidates with neuroprotective properties. The possibilities of combining this model with neurophysiological techniques (e.g., electroencephalography, electrocorticography, evoked potential registration, etc.) to assess the effectiveness of novel pharmacotherapeutic strategies appear to be of great interest to current biomedical research.The aim. Identifying specific changes in somatosensory evoked potentials occurring after cerebral ischemia induced by middle cerebral artery occlusion in rats.Materials and methods. A total number of 18 white outbred male rats were randomized into 3 groups by 6 animals in each: 1) control (presumably healthy animals); 2) ischemia-30 (30-minute middle cerebral artery occlusion); 3) ischemia-45 (45-minute occlusion). At post-surgery day 7, cortical responses to sequential electrical stimulation of left and right n. ischiadicus were registered. N1, P2, N2, P3, and N3 peak latencies and amplitudes, peak-to-peak interval durations and amplitudes were calculated. Spearman’s rank correlation coefficients were used to assess the relationship between ischemia duration and evoked potential parameters, and the Chaddock scale was used to qualitatively evaluate the strength of correlations.Results. The rats subjected to cerebral ischemia demonstrated a decrease in some of the peak amplitudes of the ipsi- and contralateral somatosensory potentials evoked by n. ischiadicus stimulation. In the injured hemisphere, decreased P2 and N3 peak and P3–N3 interval amplitudes were registered ipsilaterally, and decreased P3 peak amplitudes and N2–P3 interval durations were observed contralaterally.Conclusions. The obtained data suggest that somatosensory evoked potential registration and analysis can be used to evaluate the functional state of central nerve tracts in rats subjected to cerebral ischemia

UV-Light-Tunable p-/n-Type Chemiresistive Gas Sensors Based on Quasi-1D TiS3 Nanoribbons: Detection of Isopropanol at ppm Concentrations

The growing demand of society for gas sensors for energy-efficient environmental sensing stimulates studies of new electronic materials. Here, we investigated quasi-one-dimensional titanium trisulfide (TiS(3)) crystals for possible applications in chemiresistors and on-chip multisensor arrays. TiS(3) nanoribbons were placed as a mat over a multielectrode chip to form an array of chemiresistive gas sensors. These sensors were exposed to isopropanol as a model analyte, which was mixed with air at low concentrations of 1–100 ppm that are below the Occupational Safety and Health Administration (OSHA) permissible exposure limit. The tests were performed at room temperature (RT), as well as with heating up to 110 °C, and under an ultraviolet (UV) radiation at λ = 345 nm. We found that the RT/UV conditions result in a n-type chemiresistive response to isopropanol, which seems to be governed by its redox reactions with chemisorbed oxygen species. In contrast, the RT conditions without a UV exposure produced a p-type response that is possibly caused by the enhancement of the electron transport scattering due to the analyte adsorption. By analyzing the vector signal from the entire on-chip multisensor array, we could distinguish isopropanol from benzene, both of which produced similar responses on individual sensors. We found that the heating up to 110 °C reduces both the sensitivity and selectivity of the sensor array