Negative magneto-resistance of electron gas in a quantum well with parabolic potential

We have studied the electrical conductivity of the electron gas in parallel electric and magnetic fields directed along the plane of a parabolic quantum well (across the profile of the potential). We found a general expression for the electrical conductivity applicable for any magnitudes of the magnetic field and the degree of degeneration of the electron gas. A new mechanism of generation of the negative magnetoresistance has been revealed. It has been shown that in a parabolic quantum well with a non-degenerated electron gas the negative magnetoresistance results from spin splitting of the levels of the size quantization.Comment: 15 pages, 3 figure

Изменения ЭЭГ и БИС индекса во время ингаляционной анестезии у детей

Objective: to estimate bispectral (BIS) index and electroencephalographic (EEG) changes during anesthesia with halothane, sevoflurane, and a successive combination of sevoflurane and isoflurane, by taking into account age. Subjects and methods. Sixty children aged 3 to 17 years, who had undergone elective surgery, were randomized to 3 groups of 20 children each: 1) halothane anesthesia; 2) sevoflurane anesthesia; and 3) a successive combination of sevoflurane and isoflurane. A 1:1 oxygen-nitrous oxide mixture was used for anesthesia in all the groups. EEG (using a 6-channel computer-assisted encephalograph) and bispectral index (XP version) was continuously recorded throughout the anesthesia, except the transition to isoflurane in Group 3. Results. In the halothane group, EEG displayed a gradual reduction in basic rhythm, an increase in slow activity with the rhythm being recovered on emergence. The BIS index changed from 96—99 to 19—36 with a spike of up to 80—87 on emergence. In Groups 2 and 3 where the induction of anesthesia used sevoflurane, EEG recorded a pointed а-rhythm, increased amplitude, and rhythm synchronization. The BIS value changed from 96—99 to 19—37. In Group 2, it was 30 to 40 on anesthesia maintenance and up to 82—87 on emergence. In Group 3, the isofluorane anesthesia stage changed EEC patterns towards rhythm synchronization and gave rise to slow fluctuations in all leads. The BIS index was 30—39 on anesthesia maintenance and 80—86 on emergence. Conclusion. EEC and BIS index monitoring values corresponded to the clinical course and depth of anesthesia. The comparison of the clinical data of the course of anesthesia and the values of EEG and BIS monitoring could lead to the conclusion that BIS technology might be of informative value in children. Key words: inhalation anesthesia, electroencephalography, BIS monitoring, isoflurane, sevoflurane, halothane.Цель исследования — оценить биспектральный (БИС) индекс и электроэнцефалографические (ЭЭГ) изменения во время анестезии галотаном, севофлураном и последовательной комбинации севофлурана и изофлурана с учетом возраста. Материал и методы. 60 детей от 3-х до 17-и лет, которым проводили плановые операции, были произвольно включены в 3-е группы (в количестве 20 в каждой группе): 1-я — с анестезией галотаном; 2-я — с анестезией севофлу-раном; и 3-я — с последовательной комбинацией севофлурана и изофлурана. Для анестезии во всех группах использовалась кислородно-закисная смесь в отношении 1:1. Регистрацию ЭЭГ (6-канальный компьютерный энцефалограф) и индекса БИС (версия XP) проводили непрерывно в течение всей анестезии, кроме момента перехода на изофлуран в 3-й группе. Результаты. В группе пациентов с анестезией галотаном на ЭЭГ регистрировалась постепенная редукция основного ритма, увеличение медленной активности с восстановлением ритма при пробуждении. Индекс БИС изменялся с 96—99 до 19—36 с подъемом до 80—87 при пробуждении. Во 2-й и 3-й группах, где для вводной анестезии применялся севофлуран, на ЭЭГ регистрировался заостренный а-ритм, увеличение амплитуды, синхронизация ритма. Значение БИС изменялось с 96—99 до 19—37. При поддержании во 2-й группе БИС устанавливался на уровне от 30 до 40. При пробуждении — от 82 до 87. На этапе анестезии с изофлураном в 3-й группе ЭЭГ картина изменялась в сторону синхронизации ритма и появления медленных колебаний во всех отведениях. Индекс БИС составил 30—39 при поддержании анестезии и 80—86 при пробуждении. Заключение. Во всех исследуемых группах показатели мониторинга ЭЭГ и БИС индекса соответствовали клиническому течению и глубине анестезии. Сопоставление клинических данных течения анестезии и показателей ЭЭГ и БИС мониторинга позволило сделать вывод о том, что технология БИС может быть информативна у детей. Ключевые слова: ингаляционная анестезия, электроэнцефалография, БИС мониторинг, изофлуран, севофлуран, галотан

Ethnic minority disparities in progression and mortality of pre-dialysis chronic kidney disease : a systematic scoping review

Background: There are a growing number of studies on ethnic differences in progression and mortality for pre-dialysis chronic kidney disease (CKD), but this literature has yet to be synthesised, particularly for studies on mortality. Methods: This scoping review synthesized existing literature on ethnic differences in progression and mortality for adults with pre-dialysis CKD, explored factors contributing to these differences, and identified gaps in the literature. A comprehensive search strategy using search terms for ethnicity and CKD was taken to identify potentially relevant studies. Nine databases were searched from 1992 to June 2017, with an updated search in February 2020. Results: 8059 articles were identified and screened. Fifty-five studies (2 systematic review, 7 non-systematic reviews, and 46 individual studies) were included in this review. Most were US studies and compared African-American/Afro-Caribbean and Caucasian populations, and fewer studies assessed outcomes for Hispanics and Asians. Most studies reported higher risk of CKD progression in Afro-Caribbean/African-Americans, Hispanics, and Asians, lower risk of mortality for Asians, and mixed findings on risk of mortality for Afro-Caribbean/African-Americans and Hispanics, compared to Caucasians. Biological factors such as hypertension, diabetes, and cardiovascular disease contributed to increased risk of progression for ethnic minorities but did not increase risk of mortality in these groups. Conclusions: Higher rates of renal replacement therapy among ethnic minorities may be partly due to increased risk of progression and reduced mortality in these groups. The review identifies gaps in the literature and highlights a need for a more structured approach by researchers that would allow higher confidence in single studies and better harmonization of data across studies to advance our understanding of CKD progression and mortality

Forecasting of an environmental setting by the designed program of a computer of detection of chemical interactions

In the article are adduced a technique of detection of chemical interactions between n-components participating in processes and the operational procedure with the designed program of a computer at forecasting an environmental setting

Changes in EEG and Bispectral Index in Children during Inhalation Anesthesia

Objective: to estimate bispectral (BIS) index and electroencephalographic (EEG) changes during anesthesia with halothane, sevoflurane, and a successive combination of sevoflurane and isoflurane, by taking into account age. Subjects and methods. Sixty children aged 3 to 17 years, who had undergone elective surgery, were randomized to 3 groups of 20 children each: 1) halothane anesthesia; 2) sevoflurane anesthesia; and 3) a successive combination of sevoflurane and isoflurane. A 1:1 oxygen-nitrous oxide mixture was used for anesthesia in all the groups. EEG (using a 6-channel computer-assisted encephalograph) and bispectral index (XP version) was continuously recorded throughout the anesthesia, except the transition to isoflurane in Group 3. Results. In the halothane group, EEG displayed a gradual reduction in basic rhythm, an increase in slow activity with the rhythm being recovered on emergence. The BIS index changed from 96—99 to 19—36 with a spike of up to 80—87 on emergence. In Groups 2 and 3 where the induction of anesthesia used sevoflurane, EEG recorded a pointed а-rhythm, increased amplitude, and rhythm synchronization. The BIS value changed from 96—99 to 19—37. In Group 2, it was 30 to 40 on anesthesia maintenance and up to 82—87 on emergence. In Group 3, the isofluorane anesthesia stage changed EEC patterns towards rhythm synchronization and gave rise to slow fluctuations in all leads. The BIS index was 30—39 on anesthesia maintenance and 80—86 on emergence. Conclusion. EEC and BIS index monitoring values corresponded to the clinical course and depth of anesthesia. The comparison of the clinical data of the course of anesthesia and the values of EEG and BIS monitoring could lead to the conclusion that BIS technology might be of informative value in children. Key words: inhalation anesthesia, electroencephalography, BIS monitoring, isoflurane, sevoflurane, halothane

Epicardial fat volume is inversely correlated with the degree of diastolic dysfunction and outcome in patients with heart failure with preserved ejection fraction

Recent scholarship has shed light on the relationship between the Spanish Monarchy and the Safavid Persian Empire in the sixteenth and seventeenth centuries. Over the last twenty years, historians have outlined the strong diplomatic links between ‘the Sophi’ and ‘His Catholic Majesty’. The foundations of this relationship were set down during the reign of Shah Abbas I. This diplomatic relationship was of considerable strategic importance, being conceived of as part of a coherent military and ..