Numerical solution of the stochastic neural field equation with applications to working memory

The main goal of the present work is to investigate the effect of noise in some neural fields, used to simulate working memory processes. The underlying mathematical model is a stochastic integro-differential equation. In order to approximate this equation we apply a numerical scheme which uses the Galerkin method for the space discretization. In this way we obtain a system of stochastic differential equations, which are then approximated in two different ways, using the Euler–Maruyama and the Itô–Taylor methods. We apply this numerical scheme to explain how a population of cortical neurons may encode in its firing pattern simultaneously the nature and time of sequential stimulus events. Numerical examples are presented and their results are discussed.The authors acknowledge the financial support of the Portuguese FCT (Fundacao para a Ciencia e Tecnologia), Portugal, through projects UIDB/04621/2020, UIDP/04621/2020 (IST), UIDB/00013/2020, UIDP/00013/2020 (UMinho) and PTDC/MAT-APL/31393/2017. The authors are also grateful to the reviewers for their careful reading of the text and helpful suggestions that contributed to the improvement of the article

Polymorphism of the renin-angiotensin system genes and endothelial NO-synthase gene in obese patients with arterial hypertension

The review is dedicated to relationships between the blood pressure and body mass. Endothelial dysfunction and imbalance of neurohumoral systems, namely, the pathological increase in the activity of the renin-angiotensin system, in combination with obesity are the main mechanisms of the of the hypertonic disease pathogenesis. Here we discuss the research on polymorphism of the renin angiotensinic system genes and the endothelial synthase nitric oxide gene. The difficulty lies in the correct assessment of associations of alleles which have clinical significance. It is essential to determine precisely the associations of gene polymorphisms in the hypertonic disease with obesity. This provides an opportunity to identify new personified approaches to the treatment of patients with this complex pathology. Keywordsendothelial nitric oxide synthase, renin-angiotensin system, gene polymorphism, hypertonic disease, obesityУ статті представлений клінічно встановлений взаємозв'язок підвищеного артеріального тиску зі збільшенням маси тіла. Показано, що ендотеліальна дисфункція і дисбаланс нейро-гуморальних систем, а саме патологічне підвищення активності ренін-ангіотензинової системи, виступають провідними механізмами патогенезу гіпертонічної хвороби в поєднанні з ожирінням. Даний огляд літератури присвячений інтерпретації наукових досліджень в області поліморфізму генів ренін ангіотензинової сиcтеми і гена ендотеліальної синтази оксиду азоту. Складність полягає в правильній оцінці асоціацій алелей, які мають клінічне значення. Особливо важливо завжди точно визначати асоціації поліморфізму генів при гіпертонічній хворобі з ожирінням. Інформація про подібні асоціації і зв'язки надає можливість для пошуку нових тактик і мішеней впливу, що розвиває персоніфіковані підходи до терапії пацієнтів з даною комплексною патологією.В статье представлены данные о взаимосвязи повышения уровня артериального давления и увеличения массы тела. Показано, что эндотелиальная дисфункция и дисбаланс нейрогуморальных систем, а именно патологическое повышение активности ренин-ангиотензиновой системы выступают ведущими механизмами патогенеза гипертонической болезни в сочетании с ожирением. Данный обзор литературы посвящён интерпретации научных изысканий в области полиморфизма генов ренин ангиотензиновой сиcтемы и гена эндотелиальной синтазы оксида азота. Трудность заключается в правильной оценке ассоциаций аллелей, которые имеют клиническое значение. Особенно важно точное определение ассоциаций полиморфизма генов при гипертонической болезни с ожирением. Информация о подобных ассоциациях и связях предоставляет возможности для поиска новых тактик и мишеней для воздействия, что развивает персонифицированные подходы к терапии пациентов с данной комплексной патологией

Hydrogenation of CO in the Presence of Fe-Containing Materials Based on Carbon Supports

Hydrothermal carbonization of lignin was used to prepare a precursor of a carbon-containing support to obtain supported iron-containing catalysts for the hydrogenation of carbon monoxide. In the paper, the possibility of forming a carbon support prone to the deposition of metal ions was investigated. Deep structural transformations occurring in the polymer matrix of lignin were demonstrated by FTIR spectroscopy. The thermal stability of the support material was determined by thermal analysis in the region up to 400 °C. The formation of magnetite nanoparticles with a size of about 7‒8 nm at the stage of preliminary calcination of the metal-carbon system was shown by X-ray diffraction analysis (XRD). It was found that the resulting systems have high activity comparable to the activity of the system based on activated carbon: the conversion of carbon monoxide reached 98%, the yield of C5+ hydrocarbons reached 72 g/m3

INCREASING THE RELIABILITY OF THE INFORMATION-MEASURING AND CONTROL SYSTEM OF THE ELECTRIC DRIVE OF LASER INSTALLATIONS

Background. The actual directions of development of an adjustable electric drive are considered – increasing the efficiency of information-measuring and control systems. Materials and methods. The need to improve the methods of control of an adjustable electric drive is shown by a comparative analysis of information-measuring and control systems of electric drives in order to improve reliability indicators. The principle of operation of the information- measuring and control system of the electric drive with increased reliability indicators is considered. Results and conclusions. A comparative calculation of the reliability of electric drives based on the vector and proposed control methods

New Approaches to the Application of DART Mass Spectrometry Coupled with Planar Chromatography for the Analysis of Mixtures of Organic Compounds

A desorption cell for TLC/DART mass spectrometry is developed. An analysis of mixtures of pharmaceutical substances has shown that the proposed approach can improve the sensitivity of the method and achieve the reproducibility of the recorded mass spectra and selected ion chromatograms. © 2017, Pleiades Publishing, Ltd

New Approaches to the Application of DART Mass Spectrometry Coupled with Planar Chromatography for the Analysis of Mixtures of Organic Compounds

A desorption cell for TLC/DART mass spectrometry is developed. An analysis of mixtures of pharmaceutical substances has shown that the proposed approach can improve the sensitivity of the method and achieve the reproducibility of the recorded mass spectra and selected ion chromatograms. © 2017, Pleiades Publishing, Ltd

Transformations of tetrahydro-pyrido[4,3-d]pyrimidines [b]-condensed with isoxazole, thiazole, thiadiazole, and triazole units under the action of activated alkynes

It has been established that 5-vinyl-substituted (N-R,N-vinylaminomethyl) isoxazolo(thiazolo, thiadiazolo)pyrimidines are formed when tetrahydropyrido[3, 4-d]pyrimidines, annelated with isoxazole, thiazole, and thiadiazole units are treated with terminal alkynes as a result of opening of the tetrahydropyridine ring. 7-Methoxymethyl-substituted [N-R,N-(dimethoxycarbonylvinyl)]aminoethyl- isoxazolo- and thiazolopyrimi-dines were obtained by reaction with dimethyl acetylenedicarboxylate (ADCE). Triazolo-pyrimidoazocine was obtained for the first time from tetrahydrotriazolopyrimidine and methyl propiolate. © 2008 Springer Science+Business Media, Inc

2-Alkyl-4-oxohexahydropyrimido[4,5-d]- and -[5,4-d]azocines

It has been established that 2-R-4-oxotetrahydropyrido[4,3-d]pyrimidines, under the action of activated alkynes in methanol, form a mixture of 2-R-4-oxohexahydropyrimido[4,5-d]azocines and products of decomposition of the tetrahydropyridine ring, the 2-R-5-methoxymethyl-4-oxo-6-vinylaminoethyl- pyrimidines. Tetrahydropyrido[3,4-d]pyrimidine, isomeric at the junction of the pyrimidine and tetrahydropyridine rings, forms only the corresponding pyrimido[5,4-d]azocine, the product of expansion, under the action of methyl propiolate. © 2011 Springer Science+Business Media, Inc

Transformations of tetrahydropyrido[4′,3′:4,5]thieno[2,3-d] pyrimidin-4(3H)-ones in the presence of alkynes bearing electron-withdrawing substituents

Tetrahydropyrido[4′,3′:4,5]thieno[2,3-d]pyrimidines in the presence of activated alkynes were transformed into mixtures of pyrimido[5′,4′:4,5]thieno[3,2-d]azocines and spiro[pyridine-4, 5′-thieno[2,3-d]pyrimidines]. © 2012 Springer Science+Business Media New York