Desflurane Selectively Suppresses Long-latency Cortical Neuronal Response to Flash in the Rat

Background—The effect of inhalational anesthetics on sensory-evoked unit activity in the cerebral cortex has been controversial. Desflurane has desirable properties for in vivo neurophysiologic studies but its effect on cortical neuronal activity and neuronal responsiveness is not known. We studied the effect of desflurane on resting and visual evoked unit activity in rat visual cortex in vivo. Methods—Desflurane was administered to adult albino rats at steady-state concentrations at 2%, 4%, 6% and 8%. Flashes from a light emitting diode were delivered to the left eye at 5-second intervals. Extracellular unit activity within the right visual cortex was recorded using a 49-electrode array. Individual units were identified using principal components analysis. Results—At 2% desflurane 578 active units were found. Of these, 75% increased their firing rate in response to flash. Most responses contained early (0–100ms) and late (150–1000ms) components. With increasing desflurane concentration, the number of units active at baseline decreased (−13%), the number of early responding units increased (+31%), and number of late responding units decreased (−15%). Simultaneously, baseline firing rate decreased (−77%), the early response was unchanged, and the late response decreased (−60%). Conclusions—The results indicate that visual cortex neurons remain responsive to flash stimulation under desflurane anesthesia but the long-latency component of their response is attenuated in a concentration-dependent manner. Suppression of the long-latency response may be related to a loss of cortico-cortical feedback and loss of consciousness

Modelling of free positron states in TiHx

Electron energy structure, positron spectrum and positron characteristics of a-Ti and a-TiH[0.125] were calculated. Self-consistent calculations of the band structure were performed by the linear muffin-tin orbital method in the atomic sphere approximation. Modelling has been made on low content of hydrogen into a-Ti with expanded close-packed hexagonal cell inclusive 8 titanium atoms. Variation of sphere radiuses permitted to consider anisotropy and spherical symmetry of potential. Positron potential and positron wave function were calculated on a base of self-consistent electron density. Then positron probability of existence into TiHx lattice and lifetime were founded. Theoretical calculation indicated a satisfactory agreement of positron characteristics absolute values with the experimental data is achieved but the tendency of values with hydrogen defects increasing is not. The reason of divergence is discussed. On the basis of experimental data and theoretical calculations it was shown that different hydrogen atom states demonstrate the different influence in the lifetime spectra

Influence of Evaluation System on Effectiveness of Foreign Students' Mathematical Education

This paper studies the problems of improving the quality of mathematics education of foreign students in Tomsk Polytechnic University. We found out that changes in the evaluation system had provided students progress in studying math. The effectiveness of point rating system introduction is proved according to statistics over the last 5 years. The research involved the application of mathematical statistics, correlation analysis and variance analysis methods. Influence of different evaluation systems on the final grade is shown. We worked out that the studying time started to be used more rationally and the students’ activity increased during the term. Observational results showed a higher level of motivation, orderliness and responsibility. Assessment of the permanent knowledge confirmed the expected results

Особливості змісту професійної підготовки фахівців сфери фізичної культури та спорту щодо роботи з особами з інвалідністю

Актуальність. Ураховуючи сучасні тенденції розвитку суспільства, науки та практики, від сучасного спеціаліста з вищою освітою вимагається наявність низки нових якостей у його науковій, педагогічній і виробничій діяльності, яка пов’язана з набуттям системних, комплексних знань та вміння використовувати їх у своїй спеціальності й в організації різноманітних соціальних відносин, зокрема з особами з інвалідністю. Завдання роботи: 1) проаналізувати зміст професійної підготовки фахівців сфери фізичної культури та спорту щодо роботи з особами з інвалідністю у вищих навчальних закладах України та світу; 2) визначити особливості впровадження дисципліни «Адаптивний спорт» у структуру фахової підготовки студентів Національного університету фізичного виховання і спорту України; 3) з’ясувати основні напрями подальшого вдосконалення навчальної дисципліни «Адаптивний спорт» у структурі підготовки студентів вищих навчальних закладів спортивного профілю. Методи дослідження – аналіз й узагальнення літератури, інформаційних ресурсів мережі Інтернет; програмно-нормативних документів; компаративний метод; абстрагування, логіко-теоретичний аналіз, контент-аналіз. Результати роботи. Профільні навчальні заклади спортивної галузі намагаються враховуючи сучасні тенденції, забезпечувати збільшення обсягу та поліпшення якості знань у сфері фізкультурно-оздоровчої й спортивної роботи людей з інвалідністю, надання можливості їх практичного використання, що дає змогу готувати випускників нової формації. Висновки. Підготовка студентів, які спроможні працювати з особами з інвалідністю, ведеться в різних вищих навчальних закладах України, проте сьогодні спеціальність фахівця з адаптивної фізичної культури й спорту законодавчо не затверджена, хоча попит на таких спеціалістів значний. Серед основних напрямів удосконалення дисципліни «Адаптивний спорт» потрібно виділити такі: кадрове забезпечення; міжнародне співробітництво; наукове та інформаційне забезпечення; формування гуманістично орієнтованих фахівців

Project activity in the formation of subject competencies

The project-based learning has long established itself as one of the most stimulating methods of mastering the educational program. However, to study in depth of mathematical disciplines, project tasks must be specifically formulated for the topic being studied. The purpose of this work is to study the methodological relationship between the declared projects and the studied topic of mathematics, as well as a comparative analysis of the results of the development of three mathematical disciplines using the project method and without it. The work on the projects has been carried out for three years at our university and it is aimed at activating the independent cognitive activity of students. In 2018-2019, these were applied and educational projects, the topics for which were selected by teachers. In 2019-2020, students were given the right to independently choose a project topic based on their scientific interests and develop it. In one experimental group, students had the opportunity to consult with the teacher to find a solution to the project problem, in the other such an opportunity was not available. The results of both groups were roughly the same. The conclusion that we came to as a result of this work: project activity increases the horizons of students and allows us to see interdisciplinary connections. Project activity is more effective only if the student works closely with the teacher

Antimalarial Therapy Selection for Quinolone Resistance among Escherichia coli in the Absence of Quinolone Exposure, in Tropical South America

BACKGROUND: Bacterial resistance to antibiotics is thought to develop only in the presence of antibiotic pressure. Here we show evidence to suggest that fluoroquinolone resistance in Escherichia coli has developed in the absence of fluoroquinolone use. METHODS: Over 4 years, outreach clinic attendees in one moderately remote and five very remote villages in rural Guyana were surveyed for the presence of rectal carriage of ciprofloxacin-resistant gram-negative bacilli (GNB). Drinking water was tested for the presence of resistant GNB by culture, and the presence of antibacterial agents and chloroquine by HPLC. The development of ciprofloxacin resistance in E. coli was examined after serial exposure to chloroquine. Patient and laboratory isolates of E. coli resistant to ciprofloxacin were assessed by PCR-sequencing for quinolone-resistance-determining-region (QRDR) mutations. RESULTS: In the very remote villages, 4.8% of patients carried ciprofloxacin-resistant E. coli with QRDR mutations despite no local availability of quinolones. However, there had been extensive local use of chloroquine, with higher prevalence of resistance seen in the villages shortly after a Plasmodium vivax epidemic (p<0.01). Antibacterial agents were not found in the drinking water, but chloroquine was demonstrated to be present. Chloroquine was found to inhibit the growth of E. coli in vitro. Replica plating demonstrated that 2-step QRDR mutations could be induced in E. coli in response to chloroquine. CONCLUSIONS: In these remote communities, the heavy use of chloroquine to treat malaria likely selected for ciprofloxacin resistance in E. coli. This may be an important public health problem in malarious areas

Non-Parametric Time-Series Analysis of Cortical Gamma Functional Connectivity Under General Anesthesia

The overall goal of my research is to better understand the mechanism of general anesthesia on the central nervous system with a special reference to the loss of consciousness. Studying the effects of anesthesia on sensory perception and consciousness necessitates the examination of the spatio-temporal distribution of neural events in the primary sensory and association cortical brain regions. In this study, I applied non-parametric spectral and information-theoretic time-series analyses to quantify concentration-dependent effect of general anesthetics on spontaneous and visually evoked local field potentials in rat primary visual (Vl), parietal association (PTA), and frontal (FR) cortices. I focused on gamma (20-60 Hz) frequency components of the local field potentials as these oscillations have been suggested to play a role in the mechanism underlying consciousness [l]. The importance of the selected cortical regions in visual awareness, selective attention and working memory has been previously demonstrated [2]. The loss of righting reflex, a generally accepted behavioral index of loss of consciousness in rat [3], was assessed simultaneously with the electrophysiological recordings in rat in awake and steady state graded levels of anesthesia bracketing the point of loss of consciousness. In an attempt to reveal a unitary component of the anesthetic action producing unconsciousness, I used three general anesthetic agents halothane, isoflurane, and desflurane. These anesthetic agents belong to the family of inhalational anesthetics but have slightly different chemical structures and potencies

Non-parametric time-series analysis of cortical gamma functional connectivity under general anesthesia

I seek to understand the mechanism of anesthetic ablation of consciousness. Gamma (20-60 Hz) oscillations in cortical neuronal activity have been associated with neural processes supporting conscious perception and action (Engel et al. 2001. Trends Cogn Sci ). In my dissertation, I examined the effect of volatile anesthetics halothane, isoflurane, and desflurane on spontaneous and visually evoked gamma activity in rat primary visual cortex. I also investigated the question whether these anesthetics at doses that produce unconsciousness may interfere with the exchange of information encoded in gamma oscillations between frontal and posterior regions. Spontaneous and event-related local field potentials to sixty light flashes presented every five seconds, were recorded with chronically implanted bipolar intracortical electrodes from rat primary visual, parietal association, and frontal cortical regions in the waking state and at increasing concentrations of halothane (0-2%), isoflurane (0-2%), and desflurane (0-10%). Also, the loss of righting reflex--a generally accepted behavioral index of the loss of consciousness in rat--was assessed as a function of steady-state graded anesthetic concentrations. The local field potentials were band-pass filtered at gamma frequencies. Thomson\u27s Multitaper power spectral analysis and wavelet decomposition were used to estimate gamma power and capture its temporal and spectral variations at the time scale of neuronal communication. Transfer entropy was calculated from wavelet-transformed flash-induced gamma oscillations to quantify feedforward and feedback information exchange among primary visual, parietal association, and frontal cortices. I showed that the three anesthetic agents studied augmented gamma power at the anesthetic concentrations producing unconsciousness. Since gamma power was not reduced even at surgical anesthetic levels, this finding suggested that gamma power alone is not a correlate of volatile anesthetic-induced loss of consciousness. On the other hand, I showed that halothane, isoflurane, and desflurane selectively decreased information transfer of the feedback projection at 50 Hz more than that of the feedforward projection between frontal and posterior cortical regions at similar anesthetic concentrations. This finding supports the role of cortical feedback projection in consciousness, and suggests that the disruption of information transfer at 50 Hz along the feedback projection is a likely neurophysiological correlate of the anesthetic-induced unconsciousness

The new meaning of hybrid learning during the pandemic

The pandemic sought the international educational community with a choice: to stop the educational process until better times or to find alternative approaches to the educational process. We offer one of the variants of the educational process, which we call the hybrid form, putting a new meaning into this concept. We are considering combining on-line students with face-to-face students. Of course, the new form found can not do without the support of e-learning. Here we offer a new approach that develops computational skills, supported by STACK simulators. Thus, the purpose of this paper is to discuss a new form of the educational process and a comparative analysis of the rating results of teaching mathematics in the classical approach and using STACK simulators