bluuebunny/crossref_metadata_2025 huggingface dataset:
Обобщенный метод построения канонических схем пассивных двухэлементных двухполюсников
Authors: Трохименко Ярослав Карпович
Published: December 2022

При проектировании радиотехнических схем возникает задача построения пассивных двухполюсников, свойства которых заданы положительной вещественной функцией входной проводимости или сопротивления (1).Классические методы реализации таких функций, удовлетворяющих условиям физической осуществимости пассивным двухполюсником с элементами двух типов [1], связаны с определенными классами реализующих схем и не всегда позволяют построить каноническую схему, имеющую минимальное число элементов, желательной конфигурации. Более общий метод заключается в переборе всех схем двухполюсников, начиная с простейших, до тех пор, пока не будет найдена схема, входное сопротивление которой равно заданному. В общем случае этот метод весьма трудоемок даже в случае применения электронно-вычислительных машин [2], но он может быть значительно упрощен при предварительной оценке класса канонических схем, реализующих заданную входную функцию.
Усиление ЧМ колебаний захваченным автогенератором на туннельном диоде
Authors: Скупой В. Ф.
Published: December 2022

Рассматриваемая схема (рис. 1а) состоит из колебательной системы LC, к которой в общем случае автотрансформаторно подключены нагрузка Gн, источник сигнала е = Еcosωt с внутренним сопротивлением Ri и туннельный диод. Эквивалентная схема может быть изображена, как показано на рис. 1б, где …
К вопросу о моделировании работы когерентной радиолокационной станции с помощью ультразвука
Authors: Новокшанов М. Н.
Published: December 2022

В последние годы появились сообщения о том, что радиолокационные станции (РЛС) когерентного типа при использовании специальной обработки радиолокационных сигналов, отраженных от целей, позволяют в значительной степени улучшить параметры (например, разрешающую способность по азимуту) РЛС [1, 2].Для выявления всех возможностей такого типа станций целесообразным является моделирование их работы на ультразвуке, что позволит в условиях лаборатории осуществлять широкую программу исследований без значительных экономических затрат.
К расчету широкополосных трансформаторов ультразвуковой частоты
Authors: Русин Ю. С.
Published: December 2022

Основной трудностью при проектировании широкополосных трансформаторов ШТ является обеспечение заданной частотной характеристики, т. е. заданных значений коэффициента частотных искажений на низших и высших частотах.Для обеспечения заданной (минимальной) величины частотных искажений необходимо иметь достаточно большую индуктивность первичной обмотки и достаточно малые величины паразитных параметров ШТ.Эти требования накладывают определенные условия на конструкцию трансформатора.В основу конструирования ШТ могут быть положены следующие соображения. Известно, что наименьшей величиной индуктивности рассеяния обладает обмотка, выполненная на тороидальном сердечнике при условии равномерной намотки по всему магнитопроводу. Следовательно, если на тороидальный сердечник поместить первичную и вторичную обмотки ШТ, одну сверху другой, равномерно распределив их витки по сердечнику, то такая конструкция будет обладать весьма малым рассеянием. Однако в этом случае будет иметь место значительная величина собственной емкости.
Анализ линейных телевизионных систем по критерию среднего квадрата ошибки
Authors: Миленин Н. К.
Published: December 2022

В визуальной телевизионной системе верность передачи изображений в основном зависит от степени отличия ее частотных и фазовых характеристик от тех же характеристик в идеализированной для данного стандарта телевизионной системе, т. е. неслучайных и случайных ошибок (рис. 1).
По поводу статьи проф. М. С. Неймана «О радиотехнических специальностях»
Authors: Степаненко И. П.
Published: December 2022

Дискуссии, подобные той, которую предлагает проф. М. С. Нейман, могли бы принести немалую реальную пользу, если бы в них (хотя бы на заключительном этапе) принимало участие Министерство высшего и среднего специального образования, от которого в конечном счете зависит решение таких вопросов.Прежде всего хотелось бы полностью поддержать предположение о четкой границе между инженерами и техниками, об их количественном соотношении (примерно 1:2), а также о сокращении срока обучения техников и изменении направленности их учебных планов.
К вопросу о радиотехнических специальностях
Authors: Модель З. И.
Published: December 2022

В связи со статьей М. С. Неймана мне хотелось бы высказать свои соображения по некоторым ее положениям.Разделяя полностью сказанное М. С. Нейманом о специальности инженера-радиофизика, я отмечу еще одно крупное преимущество ее подготовки в Ленинградском политехническом институте. Радиофизики, помимо основательных знаний математики и физики, имеют, как и прочие выпускники факультета радиоэлектроники ЛПИ (он выделился из физико-механического факультета), опыт самостоятельной исследовательской работы, полученный путем длительной работы над одной темой в лаборатории (помимо учебных работ по курсам) и участия в семинарах. Этот опыт следовало бы перенести на другие радиоспециальности.
От редактора
Authors: Лебедев И. В.
Published: December 2022

Настоящий номер журнала является вторым специальным выпуском, посвященным электронике сверхвысоких частот. В отличие от первого тематического выпуска (№ 1 за 1966 г.), основное внимание уделено электронным приборам СВЧ диапазона.Нынешний этап развития СВЧ электроники характеризуется, с одной стороны, чрезвычайным разнообразием методов и конкретных типов электронных приборов, используемых для генерирования, усиления и преобразования СВЧ колебаний. Требования, предъявляемые к приборам, непрерывно возрастают. Это требует дальнейшего углубленного изучения особенностей и потенциальных возможностей существующих классов приборов СВЧ, а также поисков принципиально новых решений. С другой стороны, происходит быстрое расширение сферы применения приборов СВЧ как в специальных радиоэлектронных устройствах, так и в областях науки, техники и народного хозяйства, не связанных непосредственно с радиоэлектроникой.Статьи, включенные в настоящий выпуск, в некоторой степени отражают первую из отмеченных особенностей, хотя и не охватывают ряда важных направлений. Наиболее многочисленной является группа статей, посвященных электронным приборам со скрещенными полями, в том числе приборам, использующим взаимодействие электронов с незамедленными волнами. Далее следуют статьи, в которых рассматриваются вопросы теории приборов О-типа и Е-типа, а также работы по электронно-оптическим проблемам приборов СВЧ. В конце выпуска помещены статьи по технике электронных ускорителей и по другим проблемам техники сверхвысоких частот.Большой интерес представляет развитие твердотельных генераторов и усилителей СВЧ колебаний. Эта крупная проблема, однако, выходит за рамки данного выпуска. В статьях не нашли отражения и другие существенные вопросы — миниатюризация и микроминиатюризация устройств и приборов СВЧ диапазона, прогнозирование их долговечности и повышение надежности, а также применение приборов СВЧ в биологии, медицине, химии и в других отраслях науки и техники. К числу проблем, имеющих непосредственное отношение к электронике СВЧ, но не включенных в данный выпуск, следует отнести также создание квантовых генераторов и усилителей сверхвысокочастотного и оптического диапазонов, разработку методов модуляции и демодуляции и пр. Этим вопросам редакция журнала «Известия вузов СССР — Радиоэлектроника» уделит должное внимание в последующих выпусках.
Исследование электронной проводимости приборов магнетронного типа
Authors: Соколова Л. И.
Published: December 2022

Описывается новый метод измерения зависимости отрицательной активной электронной проводимости от амплитуды СВЧ колебаний. Метод применим к генераторам с одним и двумя выводами энергии. Анализируются погрешности, присущие описываемому способу измерения электронной проводимости. Приводятся результаты экспериментальных исследований электронной проводимости импульсных многорезонаторных магнетронов 10-сантиметрового диапазона, а также (для сравнения) отражательного клистрона 3-сантиметрового диапазона.
Строфотронные усилители бегущей волны
Authors: Альтшулер Ю. Г. , Анисимов Е. В. , Шершабова М. Д.
Published: December 2022

Развита теория строфотронных усилителей прямой и обратной волны с учетом влияния обратного излучения. Проведен приближенный расчет строфотронных усилителей. Определены величины коэффициента усиления в первом и втором приближениях, оценено влияние обратного излучения на работу строфотронного усилителя. Описаны результаты экспериментальных исследований лабораторных макетов строфотронных усилителей прямой и обратной волн.
К расчету характеристик модулятора СВЧ на полупроводниковых приборах
Authors: Бова Николай Тимофеевич , Стукало П. А.
Published: December 2022

Приведен расчет комплексного коэффициента передачи для модуляторов амплитуды и фазы, представляющих ряд параллельно присоединенных к линии варакторов или p-i-n-диодов. Получены оптимальные соотношения для модулятора амплитуды на p-i-n-диодах, и для модулятора фазы на варакторах.
Расчет коэффициента усиления параметрического усилителя на лампе бегущей волны
Authors: Бессонов В. И. , Железовский Б. Е.
Published: December 2022

Наряду с применением строгих методов анализа электронно-лучевых приборов большое значение имеют приближенные методы решения. Последние могут оказаться особенно полезными для инженерных оценок параметров исследуемых приборов.В данном сообщении получены аналитические соотношения для коэффициентов усиления основного и разностного сигналов параметрического ЛБВ-усилителя, в котором накачка распространяется в виде быстрой волны пространственного заряда. Это оказалось возможным благодаря применению для расчетов метода связанных волн [1].
К теории и расчету коаксиала с внутренним проводником в виде желоба
Authors: Советов Н. М. , Кононова Л. С.
Published: December 2022

Знание волнового сопротивления коаксиала с внутренним желобковым проводником может оказаться полезным при согласовании простой коаксиальной линии с коаксиалами более сложной формы (замедляющей системой).Для расчета оптимальных согласующих переходов важно иметь аналитическое выражение волнового сопротивления. Точное решение задачи о нахождении полей и сопротивления коаксиала с внутренним желобковым проводником затруднено асимметрией задачи.
Особенности фильтрации рэлеевского параметра импульсных сигналов в присутствии помех
Authors: Амиантов И. Н. , Заболотских В. Г.
Published: December 2022

В гауссовом приближении апостериорного распределения, но на основе точного выражения для плотности вероятности перехода, получены новые алгоритмы фильтрации марковского рэлеевского параметра сигнала в дискретном времени. Результаты конкретизированы для случая выделения рэлеевской амплитуды сигнала. Синтезирована система АРУ, позволяющая выполнять оптимальные приемники для измерения неэнергетических параметров федингующих импульсных сигналов на каскадах с ограниченным динамическим диапазоном.
Статистические характеристики оптимального обнаружителя случайно пропадающих импульсных сигналов
Authors: Казаринов Ю. М. , Катиков В. М.
Published: December 2022

Анализируется оптимальный алгоритм обнаружения некогерентной импульсной последовательности с учетом случайных пропаданий отдельных импульсов сигнала. Исследуется влияние этих пропаданий на статистические характеристики обнаружителя, включающего в себя детектор огибающей с амплитудной характеристикой, оптимизированной для бинарного закона флюктуаций сигнала.
Коды, исправляющие ошибки решетчатой конфигурации
Authors: Габидулин Э. М. , Коржик В. И.
Published: December 2022

Предложена математическая модель системы параллельных каналов, подверженных действию замираний, узкополосных помех и кратковременных импульсных помех. Рассматриваются алгебраические методы кодирования в таких каналах на основе новой, не хэмминговской метрики. Получены асимптотические совпадающие верхние и нижние границы для кодового расстояния. Описан один класс оптимальных кодов.
Характеристики оптимального алгоритма обнаружения гауссовых сигналов на фоне импульсных помех для приемников с логарифмическим усилителем
Authors: Чирков Д. В.
Published: December 2022

Рассматривается задача последетекторного обнаружения гауссова сигнала на фоне гауссова шума с постоянной дисперсией и хаотической импульсной помехи (ХИП), с известной скважностью и известной амплитудой на выходе системы: логарифмический УПЧ — линейный детектор. Предлагается на основании синтеза функциональная схема оптимального приемника обнаружения и производится анализ эффективности данного алгоритма для бинарной системы обнаружения. Приводятся характеристики обнаружения и результаты моделирования на БЭСМ-6.
Применение методов спектрального анализа в антенных измерениях
Authors: Дробахин Олег Олегович , Клименко А. Д.
Published: December 2022

Описан алгоритм получения диаграмм направленности антенн по данным измерений на многих частотах в условиях антенного полигона с низкой безэховостью. Выделение сигнала прямого луча достигается использованием параметрических методов спектрального анализа. Рассмотрены вопросы калибровки. Метод проиллюстрирован результатами экспериментов.
Параметрические колебания в RC-автогенераторе с распределенными параметрами
Authors: Камбулов Виктор Федорович , Прудниченко Александр Семенович
Published: December 2022

Рассмотрен автогенератор с RC-распределенными параметрами в цепи обратной связи при гармоническом изменении сосредоточенной емкости на выходе усилителя. В случае основного параметрического резонанса (1:2) выявлены условия, при которых в генераторе в «недовозбужденном» режиме могут возникать устойчивые колебания.
Восстановление реализаций нестационарных случайных процессов по совокупности дискретных отсчетов
Authors: Казаков Владимир Александрович , Беляев Михаил Анатольевич
Published: December 2022

Проведено статистическое описание процедуры дискретизации—восстановления для нестационарных гауссовых случайных процессов. Исследованы восстанавливающие функции и зависимости ошибок восстановления для ряда примеров.
Метод анализа параметрической чувствительности электрических фильтров по характеристикам низкочастотного прототипа
Authors: Аль-Номан А. А. , Сергеев В. В.
Published: December 2022

Предложен метод расчета параметрической чувствительности электрических фильтров по соответствующим функциям низкочастотного прототипа. Получены соотношения, связывающие функции чувствительности низкочастотного прототипа и преобразованного фильтра. На конкретном примере показана эффективность данной методики.
Cementos portland ternarios elaborados con escoria granulada de alto horno molida y cenizas volantes de carbón: desempeño de resistencia a la compresión = Ternary portland cements made with ground granulated blast-furnace slag and coal fly ash: compressive strength performance
Authors: Abnelia-Rivera Rosa , Alfonso Martín Domingo , Sanjuán Miguel Ángel
Published: December 2022

Se informó que la producción mundial de cemento Portland fue de 4650 millones de toneladas en 2016. Dicha producción de cemento exige una cantidad significativa de recursos naturales y energía. Además, la producción de una tonelada de cemento Portland emite alrededor de 0,87 toneladas de dióxido de carbono. Este valor se reduciría significativamente al utilizar cementos ternarios elaborados con residuos industriales como escoria granulada de alto horno molida (GGBFS) y cenizas volantes de carbón (CFA). Además, se promueve la economía circular mediante el uso de residuos industriales (GGBFS y CFA) y se aumenta la durabilidad del hormigón en ambientes agresivos. Por el contrario, inducen un retraso en la ganancia de resistencia a la compresión como resultado de la reacción puzolánica. En este trabajo se ensayaron mezclas ternarias de cemento con proporciones GGBFS y CFA (25% y 40%) sobre morteros estándar. En consecuencia, se realizaron medidas de resistencia a la compresión a los 2, 7 y 28 días. Se discutieron las interacciones estadísticas entre GGBFS y CFA en los resultados de resistencia a la compresión de los morteros de cemento Portland ternarios.AbstractGlobal production of Portland cement was reported to be 4.65 billion tons in 2016. Such cement production demands a significant amount of natural resources and energy. Furthermore, the production of one tonne of Portland cement emits about 0.87 tons of carbon dioxide. This value would be reduced significantly by using ternary cements made with industrial wastes such as ground granulated blast-furnace slag (GGBFS) and coal fly ash (CFA). In addition, circular economy is promoted by using industrial wastes (GGBFS and CFA) and the concrete durability in aggressive environments is increased. By contrast, they induce a delay in the compressive strength gain as result of the pozzolanic reaction. In this paper, ternary cement mixes with GGBFS and CFA proportions (25% and 40%) were tested on standard mortars. Accordingly, compressive strength measures at 2, 7 and 28 days was performed. Statistical interactions between GGBFS and CFA on the compressive strength results of ternary Portland cement mortars were discussed.
A pedagogia de Célestin e Élise Freinet transpondo fronteiras (Itália, 1974-1980)
Authors: Jinzenji Mônica Yumi , Boroni Junia , André Mariana Gonçalves
Published: December 2022

Este artigo, baseado em pesquisa documental de cunho historiográfico, analisa jornais escolares produzidos por estudantes de escolas elementares da região norte da Itália no período de 1974 a 1980. Por meio dos referenciais da História da Leitura e em diálogo com os estudos em História da Educação, analisa-se o desenvolvimento e a internacionalização dessa prática educativa, proposta por Célestin e Élise Freinet desde a década de 1920; nesse processo, verifica-se o uso dos jornais como substitutos dos manuais e livros nas atividades escolares, o seu papel na integração entre a escola e as famílias, e a produção da centralidade dos estudantes como produtores de conhecimento e como sujeitos críticos das desigualdades e injustiças sociais.
El archivo y biblioteca de la Fundación Ferrer Guardia. Análisis de su fondo documental
Authors: Garau Rolandi Miguel
Published: December 2022

Este artículo repasa la vida y obra de Francisco Ferrer Guardia, dando a conocer el amplio y rico fondo documental que custodia el archivo y la biblioteca de la Fundación Ferrer Guardia de Barcelona. Esta entidad se ha dedicado a la conservación de estos materiales, donados por los descendientes de Ferrer, y a la preservación de su memoria desde su fundación en 1987. El artículo reseña la trayectoria política, social y personal del pedagogo catalán, haciendo especial hincapié en su labor editorial y sus vinculaciones con el anarquismo, a partir de su propio fondo archivístico. Asimismo, detalla las actuaciones que la Fundación ha emprendido a lo largo de sus 35 años de andadura para expandir el conocimiento sobre la figura de Ferrer entre la ciudadanía y para poner a disposición del público general y especializado su vasto fondo documental.
2-Isobutyl-3-methoxypyrazine as a Putative Male-Specific Aggregation Pheromone in Labidostomis lusitanica (Germar) (Coleoptera: Chrysomelidae)
Authors: López Sergio , Rodrigo-Gómez Sara , Fernández-Carrillo Enrique , Corbella-Martorell Cláudia , Quero Carmen
Published: December 2022

In spite of its incidence on pistachio trees, the chemical ecology of Labidostomis lusitanica (Germar) (Coleoptera: Chrysomelidae) has been neglected so far. In this work we provide the first evidence of a biologically active male-specific compound that may be promoting field aggregation. Headspace collections by solid-phase microextraction from feral males and females reported the presence of 2-isobutyl-3-methoxypyrazine exclusively on males. Electroantennographic recordings revealed that males and females responded in a dose-dependent manner to increasing stimuli of 2-isobutyl-3-methoxypyrazine, with females overall displaying a higher response than males. In dual-choice tests, both males and females showed a significant preference for the compound in comparison to a pure air stimulus. In the light of these results, the possible role of 2-isobutyl-3-methoxypyrazine as an aggregation cue in L. lusitanica is discussed.
Longitudinal Registration of Chest CT Images With Radiation-Induced Lung Disease
Authors: Lin Fan-Ya , Li Ya-Jing , Lee Chi-En , Lor Kuo-Lung , Wang Hao-Jen , Chang Yeun-Chung , Chen Chung-Ming
Published: December 2022

Longitudinal image registration of pulmonary computed tomography (PCT) images may serve as an essential tool for investigating the relationship between radiation dose distribution and the occurrence and phenotype of radiation-induced lung disease (RILD). Although numerous longitudinal registration algorithms have been developed for PCT, most similarity-based approaches are not suitable for PCT involving RILD due to the complex tissue variation between two PCT images. Moreover, conventional feature-based approaches might fail to find a sufficient number of matched pairs of feature points due to the disparate lung deformation caused by breathing and RILD. To overcome the challenges resulting from RILD, component structure coherence point drift (CSCPD) was proposed to establish a deformation model by decomposing the chest into several components and matching them with individual parameters based on coherence point drift (CPD). Moreover, a regional vascular point matching (RVPM) algorithm was proposed to generate a vascular subtree and to substantially increase the number of corresponding pairs between two images. Eventually, the components were recomposed and aligned by a thin plate spline algorithm. A performance assessment on 15 pairs of PCT images of patients with RILD yielded recall and precision values of 0.85 and 0.89 for RVPM, respectively. Moreover, the target registration error of CSCPD with RVPM (2.3 ± 1.79) was significantly better than that of conventional CPD with RVPM (2.95 ± 1.89) and conventional CPD (5.04 ± 2.87). Therefore, the proposed registration system is robust enough to address the disparate deformation of lungs with RILD, and it improves registration accuracy within the parenchyma.
The culture of care and sense of belonging as drivers of sustainability in higher education
Authors: Bizerril Marcelo Ximenes Aguiar , Arrais Antonia Adriana Mota , Silva Nayara P. Martins
Published: December 2022

The purpose of this article is to examine how a culture of care and sense of belonging are related to environmental behavior and how it can be fostered in higher education. To support this analysis, the concepts and the ways of strengthening the sense of care and belonging are discussed based on literature and experiences developed on a campus of the University of Brasilia, Brazil. The physical environment and participation tools on campus are presented, as well as the results of a survey on the perception of the academic community about the quality of life on campus, answered by 10.5% of the campus population. The quality of life on campus was rated as good or excellent by 90% of respondents. The feeling of personal responsibility in taking care of people and in the campus environment was confirmed by 41% of respondents. We relate this perception to the community's participation in outreach and sustainability programs. Sustainability policies in higher education must prioritize the promotion of a culture of care and sense of belonging. These values are essential for the humanistic education of postsecondary students in a planetary reality that must be radically transformed, aiming at the transition to sustainable societies.
Experience report: Transitions during Covid-19 Outbreak and the Day Care Centers Closure
Authors: Rengifo-Herrera Francisco José , Mietto Gabriela Sousa de Melo , Alencar Ana Carolina Corrêa
Published: December 2022

Covid-19 outbreak forced the governments around the world to decide schools closure. In Brazil this circumstance lasted almost two years because a government wrong management had been marked by delays and lack implementation of public policies. The outbreak context brought important challenges for children and their families. This paper carried out a characterization and analysis of a questionnaire to assess the perception of fifteen families about care, socialization/learning, feeding and development of autonomy in shared context with children during the pandemic in a public day care center. Results show that families faced difficulties in socializing and playing. Feeding practices and use of objects-utensils during mealtimes and care had better indicators. However, difficulties in autonomy, learning, and anxiety increased. As a conclusion, the impact of pandemic changes must be evaluated, revealing actions that the school will have to carry out in the future, especially on children's development/learning processes.
Increasing Vocabulary Resources for Primary School Students
Authors: Hasanboy Abdullayeva Nodirahon
Published: December 2022

This article explains how to explain the meaning of a word to elementary school students and how to activate a primary school dictionary.
Implementation of The Scientific Method in Students' Logical Thinking Skills in The 5th Grade Science Material of Islamic Elementary School
Authors: Rozhak Miftakhur , Nurdyansyah
Published: December 2022

In this study, the authors raised the issue of how to implement the scientific method in the logical thinking skills of students in the fifth grade science material at MI Ma'arif Kedensari. Based on the results of the interview with the fifth grade teacher, Mi Ma'arif, who said that the learning outcomes of some students in fifth grade were still below the KKM standard which should have been able to reach a score of 75, this was due to the factor of delays in students' thinking and also the less than optimal model. used by the teacher. The purpose of this study was to determine the Implementation of Scientific Methods in Students' Logical Thinking Skills in Science Subject Class V MI Ma'arif Kedensari. To achieve the objectives in this study, the research method used by the researcher is a qualitative descriptive method, in which the research method is based on valid science, and other facts that may become objects of knowledge by using observation, interview, and documentation techniques. to complete the data and information needed by researchers. The results of this study indicate that the use of scientific methods in students' logical thinking skills in learning natural science class V MI Ma'arif Kedensari has increased because when learning takes place students are able to construct knowledge by thinking and reasoning using logic to complete tasks based on knowledge and experience in daily activities and new knowledge given during discussion activities.
The Success of the Population Administration Service Program Through the e-PAK LADI Kiosk in Pasuruan Regency
Authors: Agustin Shenia , Mursyidah Lailul
Published: December 2022

This study aims to analyze and describe the effectiveness of population administration services through the e-PAK LADI Kiosk in Jatiarjo Village, Prigen District, Pasuruan Regency. This research is a qualitative descriptive study using purposive sampling informant determination technique. Techniques for collecting data are interviews, observations, documentation and literature studies. The data analysis technique uses Miles and Huberman which consists of four components, namely data collection, data reduction, data presentation and drawing conclusions. The results of this study indicate that there is a need for an increase in the number of service operators, a positive response from the community towards the e-PAK LADI Kiosk service, an increase in the number of issuance of documents such as KK, KIA and others without any fees to the community. And there are facilities and infrastructure that support the service activities of the e-PAK LADI Kiosk such as printing, paper drives, wifi and so on.
Systematic Review of Barriers and Facilitators to Complementary Feeding in Preterm Infants
Authors: Li Jun , Liu Xiyao , Zeng Lin , Zhou Qianling , Han Tongyan
Published: December 2022

Background: It has been reported that preterm infants may experience feeding difficulties in complementary food introduction. There is a lack of a comprehensive summary of the current evidence of the difficulties in complementary food introduction of preterm infants and how to intervene or solve these difficulties. So the purpose of this review is to systematically analyze the difficulties and solutions in the existing literature on it.
Methods: A literature search was conducted in PubMed, Web of Science, Cochrane library and Scopus databases for the studies about complementary feeding in preterm infants. The time range of the search was from January 2012 to December 2021. Included studies were summarized and organized into two perspectives: (1) the difficulties of complementary feeding in preterm infants; (2) related factors influencing feeding difficulties and possible interventions.
Results: A total of 6 articles were included in the systematic review ultimately. Three studies were cross-sectional study and the other three were longitudinal study. The current evidence demonstrated that feeding problems such as vomiting, gagging, food refusal, and chewing and swallowing difficulty might occur in complementary foods introduction in preterm infants. And preterm infants were more likely to experience these difficulties than full-term infants. Possible causes of these feeding difficulties include endotracheal intubation, gastric tube feeding, formula feeding, neonatal surgery, parenteral nutrition, etc. However, the available literatures do not provide specific intervention methods or guidelines to facilitate the complementary feeding in preterm infants.
Conclusions: More experiments are needed to explore appropriate interventions to solve the problems and facilitate complementary feeding in preterm infants during infancy, and promote catch-up growth and develop good eating habits for preterm infants.
Understanding the spatial heterogeneity of Covid-19 vaccination uptake: a case study of England
Authors: Chen Huanfa , Cao Yanjia , Feng Lingru , Zhao Qunshan , Torres José Rafael Verduzco
Published: December 2022

Background
The global Covid-19 pandemic has caused numerous deaths and illnesses, posing unprecedented social and economic challenges to many countries. One of the key strategies to contain the pandemic is mass vaccination programme. However, vaccination rates vary across space and socio-economic factors, and are likely to depend on the accessibility to vaccination services. There is a lack of quantitative understanding of how spatial-socio-economic factors influence the Covid-19 vaccination rates in England.
Methods
We investigated the percentage of over-18 fully vaccinated people at the small-area level across England up to 18 November 2021. We used (multiscale) geographically weighted regression to model the spatially heterogeneous relationship between vaccination rates and socio-economic determinants, including ethnic, age, economic, and accessibility factors.
Results
This study indicates that the selected model can explain 83.2% of the total variance of vaccination rates. The variables exhibiting a positive association with vaccination rates in most areas include proportion of population over 40, car ownership, average household income, and accessibility to vaccination. In contrast, population under 40, low multiple deprivation level, and black or mixed ethnicity are negatively associated with the vaccination rates.
Conclusions
Our findings indicate the importance of improving the spatial accessibility to vaccinations in developing regions and among specific population groups in order to promote Covid-19 vaccination.
Injectable bioactive copper-based metal organic framework embedded dual-crosslinked alginate hydrogel for potential antimicrobial applications
Authors: Gwon Kihak , Lee Seonhwa , Kim Youngmee , Choi Jun , Kim Sujin , Kim Sung-Jin , Hong Hye Jin , Hwang Youngmin , Mori Munemasa , Lee Do Nam
Published: December 2022

Background:
The antibiotic resistance of pathogenic microbes due to the overuse of antibiotics is a growing threat to the public health and can eventually reduce the therapeutic effects of antibiotics. Hydrogel-based systems for local delivery of antibiotics can be a solution to this problem. Metal-organic frameworks (MOFs) have received considerable interest for use as antimicrobial materials due to their high porosity, large surface area to volume, diverse structures, and tunable topologies.
Methods:
In this study, we developed MOF-encapsulated and dual (photo & chemical)-crosslinkable alginate hydrogel as an antimicrobial scaffold. We synthesized antimicrobial Cu(AZPY)-MOF using solvothermal reaction and encapsulated them in an alginate-based hydrogel via visible light photo-crosslinking and calcium ion-induced chemical-crosslinking processes.
Results:
Powder X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy confirmed the successful fabrication of Cu(AZPY)-MOF encapsulated alginate hydrogel. The mechanical strength of the dual-crosslinked hydrogels was better than that of the photo-crosslinked hydrogel. Encapsulation of Cu(AZPY)-MOF in an alginate hydrogel resulted in a further increase in the mechanical strength of the hydrogel owing to the additional interaction of alginate with Cu-MOF. Moreover, the Cu(AZPY)-MOF encapsulated alginate hydrogel exhibited excellent antibacterial and antifungal properties against two bacterial strains (i.e., MRSA and S. mutans) and one fungal strain (C. albicans) as well as negligible cytotoxicity toward MEFs.
Conclusions:
The antimicrobial agents encapsulated dual-crosslinkable alginate hydrogel developed in this study is a promising candidate for use in tissue engineering and biomedical field.
A comprehensive mechanistic model of adipocyte signaling with layers of confidence
Authors: Lövfors William , Magnusson Rasmus , Jönsson Cecilia , Gustafsson Mika , Olofsson Charlotta , Cedersund Gunnar , Nyman Elin
Published: December 2022

Adipocyte cellular signaling, normally and in type 2 diabetes, is far from fully understood. We have earlier developed detailed dynamic mathematical models for a number of well-studied, and partially overlapping, signaling pathways in adipocytes. Still, these models only cover a fraction of the total cellular response. For a broader coverage of the response, large-scale phosphoproteomic data and systems level knowledge on protein interactions are key. However, methods to combine detailed dynamic models with large-scale data, using information about the confidence of included interactions, are lacking. Here, we have created a new method where we first establish a core model by connecting our partially overlapping models of adipocyte cellular signaling with focus on: 1) lipolysis and fatty acid release, 2) glucose uptake, and 3) the release of adiponectin. We then use prior knowledge on protein interactions to identify phosphosites downstream of the core model. Using publicly available phosphoproteome data for the insulin response in adipocytes, we test if the identified downstream phosphosites can be added to the model. The additions of the downstream phosphosites are tested in a parallel pairwise approach with low computation time. We iteratively collect the accepted additions into a layer, and use the newly added layer to find new downstream phosphosites. We find that the first 15 layers (60 added phosphosites) with the highest confidence can correctly predict independent inhibitor-data (70-90 \% correct), and that this ability decrease when we add layers of decreasing confidence. In total, 60 layers (3,926 phosphosites) can be added to the model and still keep predictive ability. Finally, we use this large layered model to simulate systems-wide alterations in adipocytes in type 2 diabetes -- simulations made possible for the first time -- with the method developed herein.
What the Phub? Consequences of phone snubbing behavior at work: a mixed-method experiment
Authors: Ochs Carli , Jaunin Astride , Kosnowski Nathalie , Sauer Juergen
Published: December 2022

This mixed-method experiment aimed to investigate the impact of phubbing (i.e. ignoring someone while giving attention to one’s smartphone) on performance, first impressions, and subjective state. 93 participants took part in a simulated job interview based on the Trier Social Stress Test, composed of an interview and a mental arithmetic task. During both tasks, participants in the experimental group were repeatedly phubbed. Results of a within-session analysis revealed that participants in the experimental group performed significantly faster on a mental arithmetic task when they were not phubbed. As expected, phubbed participants judged the interviewer to be less professional and less fair than participants in the control group. Furthermore, the participants’ subjective state was affected by phubbing, with self-esteem decreasing and negative affect increasing. Lastly, a qualitative analysis of participants' responses revealed tendencies to rationalize the interviewer’s phubbing behavior. This study demonstrated negative effects of phubbing on first impressions, subjective state and objective measures of performance in a professional setting.
Nonlinear feedback, double bracket dissipation and port control of Lie-Poisson systems
Authors: Hochgerner Simon
Published: December 2022

Methods from controlled Lagrangians, double bracket dissipation and interconnection and damping assignment -- passivity based control (IDA-PBC) are used to construct nonlinear feedback controls which (asymptotically) stabilize previously unstable equilibria of Lie-Poisson Hamiltonian systems. The results are applied to find an asymptotically stabilizing control for the rotor driven satellite, and a stabilizing control for Hall magnetohydrodynamic flow.
Niche shift and global potential distribution of the invasive species Trioza erytreae, vector of the citrus Huanglongbing disease
Authors: Pérez-Bonet Sergio , López María Ángeles , Abellán Pedro
Published: December 2022

Invasive species pose a major threat to biodiversity, ecological structure of habitats and agriculture, especially in a setting of climatic change. The impact of these species also has a major role in the spread of exotic vector-borne diseases, which may cause substantial economic losses in agriculture if cultivated species are among those affected by these diseases. The African citrus psyllid, Trioza erytreae (Del Guercio), has recently become an invasive species in Europe. This species, which has been known as a pest of trees in the family Rutaceae in Africa for a long period of time, is cause for major concern by its potential effects on citrus orchards, of particular economic importance in southern European countries. Through the evaluation of macroclimatic niches occupied by invasive and native populations and the use of species distribution modelling, we have predicted the potential global geographic distribution of the species, which shows high suitability in a wide range of areas in every continent, as well as quantified and evaluated differences in the macroclimatic niches occupied by invasive and native populations of the species, demonstrating a high similarity and therefore conservatism between the climatic conditions occupied by the species in both ranges. These results provide valuable information that can be used in planning conservation actions in order to reduce risk of invasion by the species.
Up-regulation of miR-208a aggravates high-fat -diet-induced cardiomyocytes injury by targeting IRS-2/PI3K/AKT pathway
Authors: Bi Ye , Wang Yan , Wang Yao , Wang Zhibin , Sun Lan
Published: December 2022

Background: Previous studies found that the myocardial function is damaged in obese mice induced by a high-fat diet, with the increased miRNA-208a and decreased IRS-2.
Method: Herein, miR-208a(-/-) knockout and C57BL/6J wild-type mice were divided into the normal diet and high‑fat diet groups, separately. Expressions of p-IRS-2, PI3K, p-AKT, NPPA, AKT, IRS-2, MYH6, MYH7 and Glut4 were determined using immunohistochemical staining. Furthermore, western blotting was performed to identify proteins.
Cardiomyocytes were isolated from neonatal rats, and the cardiomyocytes injury model was induced by PA. CCK-8 was conducted to assess the viability of cardiomyocytes, and the glucose uptake of cardiomyocytes was measured using glucose uptake test.
Result: H&E staining revealed that the degree of hypertrophy and swelling of cardiomyocytes and cardiac fibrosis of miR208a-/- knockout mice in the high-fat diet group was significantly increased. Moreover, high levels of IRS-2, p-AKT, AKT, NPPA ,GLUT4, MYH7 and MYH6 expression in miR208a-/- knockout mice. Therefore, AKT, MYH6, IRS-2, NPPA in miR208a-/- knockout mice of high-fat diet.
In PA-treated cardiomyocytes, the viability was markedly declined and glucose uptake was significantly reduced, while the lipid accumulation and fibrosis were significantly enhanced. Most importantly, the cardiomyocytes injury induced by PA was aggravated in miR-208a-3p upregulated cardiomyocytes, but alleviated in miR-208a-3pdownregulated cardiomyocytes.
Conclusion: Our results indicate that the high expression of miR-208a promote the suppression of IRS-2/PI3K/AKT signaling pathway. Meanwhile, miR-208a-3p contributes to promoting PA-induced cardiomyocyte injury, which may be a biomarker of cardiomyocyte injury in lipotoxic cardiomyopathy.
Relationships between carboxylate-based nutrient-acquisition strategies, phosphorus-nutritional status and rare earth element accumulation in plants
Authors: Wiche Oliver , Dittrich Christine , Pourret Olivier , Monei Nthati , Heim Juliane , Lambers Hans
Published: December 2022

Background and Aims A split-root approach was used to explore how phosphorus (P) nutrition influences accumulation of rare earth elements (REE) in plant species with different P-acquisition strategies beyond the commonly explored REE-phosphate precipitation.
Methods Six species (Triticum aestivum, Brassica napus, Pisum sativum, Cicer arietinum, Lupinus albus, and Lupinus cosentinii) were cultivated with a split-root system on two sand types. Phosphorus availability was controlled on one root side by watering the plants with different P-containing solutions (100 µM P, 0 µM P). Carboxylate release and changes in pH were measured on both sides. Concentrations of nutrients, cadmium (Cd), aluminium (Al), light REE (LREE: La–Eu), and heavy REE (HREE: Gd–Lu, including Y) in roots and shoots were analyzed by ICP-MS.
Results Triticum aestivum, B. napus and C. arietinum did not respond to a low P supply with elevated carboxylate release. These species accumulated more REE when the P supply was low and higher REE concentrations were proportional to declining plant growth. However, P. sativum, L. albus and L. cosentiniiaccumulated less REE when P-supply was low. Plants that strongly acidified the rhizosphere and released low quantities of dicarboxylates accumulated more REE (with higher LREE/HREE ratios) than species that released tricarboxylates.
Conclusion Our findings suggest that REE accumulation strongly depended on rhizosphere acidification, in concert with the amount and composition of carboxylates determining the exclusion of REE-carboxylate complexes. Leaf REE signatures may be a promising indicator as a screen tool for carboxylate-based processes in the rhizosphere using an ionomic approach.
Zeolite-Y loaded chitosan nanoparticles nanocomposite as endodontic intra-canal medicament: synthesis, antimicrobial and cytotoxic activity: An in vitro study
Authors: Ibrahim Amir I. O. , Moodley Desigar , Maboza Ernest , Olivier Annette , Petrik Leslie
Published: December 2022

Objectives
To synthesize a bioactive nanocomposite intra-canal medicament using chitosan nanoparticles (Ch-Np), loaded into Zeolite-Y as a carrier, and evaluate its antimicrobial activity in the presence and absence of tissue inhibitors. Also, to evaluate its cytotoxic activity against fibroblast cells.
Materials and methods
A concentration of 3% (w/v) electrosprayed Ch-Np was mixed with Zeolite-Y in a concentration of 53.3 (w/v) and characterized using Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy Analysis (EDS). The antimicrobial activity was evaluated against Streptococcus mutans and Enterococcus faecalis using the agar diffusion test, and Time-Kill Test performed by using the broth micro-dilution technique in presence of tissue inhibitors. The cytotoxicity was evaluated against Balb/c 3T3 mouse fibroblast cells using the standard MTT assay.
Results
The mixture resulted in a white paste with a crystalline-like structure under SEM. EDS analysis showed a reduction in the anatomical percentage of Zeolite-Y, indicating cation exchange with Ch-Np. A mean diameter inhibition zones of 9.57 mm for S. mutans and 7.85 mm for E. faecalis were observed, indicating antimicrobial activity. S. mutans and E. faecalis were completely eradicated in the presence of tissue inhibitors. The Ch-Np-Zeolite nanocomposite promotes the growth of 3T3 fibroblast cells significantly (p = 0.00).
Conclusions
Zeolite-Y loaded chitosan nanoparticle nanocomposite completely eradicated S. mutans and E. faecalis even in the presence of tissue inhibitors while maintaining its biocompatibility.
Clinical relevance:
The novel Ch-Np-Zeolite nanocomposite exhibits antimicrobial activity against endodontic pathogens while maintaining its biocompatibility, providing the potential to be used as a novel intra-canal medicament.
Characterization of Aircraft Gasper Jet Flow using Computational Fluid Dynamics Method
Authors: Sriniv Vinod Kumar , Kattimani Subhaschandra , Reddy Ganga
Published: December 2022

The air distribution in cabins is primarily intended to provide occupant thermal comfort and maintain oxygen adequacy through common vents and personalized gaspers. Passengers are susceptible to disease transmission and infection if the correct ventilation systems are not implemented. A good understanding of gasper jet flow is needed, and the estimation of mean velocity and turbulence intensity are good indicators of mixing phenomenon. Gasper jet flow is simulated at isothermal conditions with a commercial numerical code using the Computational Fluid Dynamics (CFD) method. Sensitivity studies are performed to observe the influence of grid topologies and turbulence models on simulation results. A Mean velocity of the gasper jet along its centerline is compared with experimental data obtained through a hot wire anemometer, and a good correlation is achieved. Further, sensitivity studies show that the gasper flow can be precisely predicted through numerical methods, and the same can be adopted for full-fledged cabin level simulations that empower simulation-based assessments of improved gasper designs.
Geodesics, Weighted Sasaki Metric and the Tangent Bundle
Authors: Wang Jian , Wang YuDan
Published: December 2022

A geodesic on the tangent bundle of a Riemannian manifold M , equipped with the Weighted Sasaki metric, can be considered as a curve on M together with a vector field along it. Following the results of Sasaki, we investigated the curvature properties and geodesics of the tangent bundle with Weighted Sasaki metric on Riemannian manifolds. The purpose of the present article is to obtain sufficient conditions for the geodesics of the tangent bundle with Weighted Sasaki metric to be flat.
2000 MSC: 53C07, 53C22, 53C25