Fractional diffusion modeling of ion channel gating

An anomalous diffusion model for ion channel gating is put forward. This scheme is able to describe non-exponential, power-law like distributions of residence time intervals in several types of ion channels. Our method presents a generalization of the discrete diffusion model by Millhauser, Salpeter and Oswald [Proc. Natl. Acad. Sci. USA 85, 1503 (1988)] to the case of a continuous, anomalous slow conformational diffusion. The corresponding generalization is derived from a continuous time random walk composed of nearest neighbor jumps which in the scaling limit results in a fractional diffusion equation. The studied model contains three parameters only: the mean residence time, a characteristic time of conformational diffusion, and the index of subdiffusion. A tractable analytical expression for the characteristic function of the residence time distribution is obtained. In the limiting case of normal diffusion, our prior findings [Proc. Natl. Acad. Sci. USA 99, 3552 (2002)] are reproduced. Depending on the chosen parameters, the fractional diffusion model exhibits a very rich behavior of the residence time distribution with different characteristic time-regimes. Moreover, the corresponding autocorrelation function of conductance fluctuations displays nontrivial features. Our theoretical model is in good agreement with experimental data for large conductance potassium ion channels

Біотехнологічні дослідження під час розроблення функціонального продукту з пробіотичним компонентом

Aim. To develop the composition of a functional fermented product for therapeutic and preventive nutrition based on propionic acid bacteria enriched with carbohydrate-containing component – honey. Materials and methods. The study objects were a lyophilized starter of propionic acid bacteria (Propionibacterium freudenreichii subsp. shermanii), milk, honey and samples of a functional fermented product made on the basis of these components. We used physico-chemical methods (determination of titrated acidity; pH determination), microbiological methods (Koch cup method; Gram stain), technological methods (determination of the syneresis degree), and organoleptic methods (the sensory profile) in our study. The statistical processing of results was carried out using the Excel software for Windows. Results and discussion. During the experimental studies it was found that the required amount of the sowing material (starter) to obtain a product of the proper quality should be 3.75 % of the amount of the raw material (propionic acid bacteria – 106 CFU/ ml). It was proven that the optimum parameters of the main biotechnological stage of the drink preparation process were: temperature – 30 °С, time – 12 h, conditions – anaerobic. It was shown that adding 5 % of honey improved the organoleptic, physico-chemical parameters of the product, increased its biological value and reduced the time of the technological process. Conclusions. According to the results of the technological, physico-chemical, microbiological tests the composition of the fermented product based on propionic acid bacteria enriched with honey has been developed. The product developed meets the nutritional needs and is an additional source of biologically active substances; it will increase the immune status of the body and contribute to improving its overall health.Целью работы является разработка состава функционального ферментированного продукта для лечебно-профилактического питания на основе пропионовокислых бактерий, обогащенного углеводосодержащим компонентом – медом. Материалы и методы работы. Объектами исследования были лиофилизированная закваска пропионовокислых бактерий (Propionibacterium freudenreichii subsp. shermanii), молоко, мед и образцы функционального ферментированного продукта, изготовленного на основе этих компонентов. Физико-химические методы: определение титрованной кислотности; определение рН. Микробиологические методы: чашечный метод Коха; окраска по Грамму. Технологические методы: определение степени синерезиса. Органолептические способы: сенсорный профиль. Статистическую обработку результатов проводили с помощью программного обеспечения Excel для Windows. Результаты и обсуждение. В ходе экспериментальных исследований было доказано, что необходимое количество посевного материала (закваски) для получения продукта должного качества должно составлять – 3,75% от количества сырья (пропионовокислые бактерии 106 КОЕ/мл). Доказано, что оптимальными параметрами основной биотехнологической стадии процесса приготовления напитка являются: температура – 30 °С, время – 12 ч, условия – анаэробные. Показано, что добавление 5% меда улучшает органолептические, физико-химические показатели продукта, повышает биологическую ценность и сокращает время технологического процесса. Выводы. На основе технологических, физико-химических, микробиологических испытаний разработан состав ферментированного продукта на основе пропионовокислых бактерий, обогащенный медом. Разработанный продукт удовлетворяет потребности в пищевой ценности и является дополнительным источником биологически активных веществ, что повысит иммунный статус организма и будет способствовать улучшению здоровья.  Метою роботи є розроблення складу функціонального ферментованого продукту для лікувально-профілактичного харчування на основі пропіоновокислих бактерій, збагаченого вуглеводовмісним компонентом – медом. Матеріали та методи. Об’єктами дослідження були ліофілізована закваска пропіоновокислих бактерій (Propionibacterium freudenreichii subsp. shermanii), молоко, мед та зразки функціонального ферментованого продукту, виготовленого на основі цих компонентів. Фізико-хімічні методи: визначення титрованої кислотності; визначення рН. Мікробіологічні методи: чашковий метод Коха; забарвлення за Грамом. Технологічні методи: визначення ступеня синерезису. Органолептичні методи: сенсорний профіль. Статистичне обробляння результатіввиконували за допомогою програмного забезпечення Excel для Windows. Результати та їх обговорення. Під час експериментальних досліджень було доведено, що необхідна кількість посівного матеріалу (закваски) для отримання продукту належної якості має становити 3,75 % від кількості сировини (пропіоновокислі бактерії 106 КУО/мл). Оптимальними параметрами основної біотехнологічної стадії процесу приготування напою є: температура – 30 °С, час – 12 год, умови – анаеробні. Доведено, що додавання 5 % меду покращує органолептичні, фізико-хімічні показники продукту, підвищує його біологічну цінність та скорочує час технологічного процесу. Висновки. На основі технологічних, фізико-хімічних, мікробіологічних випробувань розроблено склад ферментованого продукту на основі пропіоновокислих бактерій, збагачений медом. Розроблений продукт задовольняє потреби в харчовій цінності та є додатковим джерелом біологічно активних речовин, що підвищить імунний статус організму і сприятимє покращенню здоров’я

Levy stable distributions via associated integral transform

We present a method of generation of exact and explicit forms of one-sided, heavy-tailed Levy stable probability distributions g_{\alpha}(x), 0 \leq x < \infty, 0 < \alpha < 1. We demonstrate that the knowledge of one such a distribution g_{\alpha}(x) suffices to obtain exactly g_{\alpha^{p}}(x), p=2, 3,... Similarly, from known g_{\alpha}(x) and g_{\beta}(x), 0 < \alpha, \beta < 1, we obtain g_{\alpha \beta}(x). The method is based on the construction of the integral operator, called Levy transform, which implements the above operations. For \alpha rational, \alpha = l/k with l < k, we reproduce in this manner many of the recently obtained exact results for g_{l/k}(x). This approach can be also recast as an application of the Efros theorem for generalized Laplace convolutions. It relies solely on efficient definite integration.Comment: 12 pages, typos removed, references adde

Static Solitons of the Sine-Gordon Equation and Equilibrium Vortex Structure in Josephson Junctions

The problem of vortex structure in a single Josephson junction in an external magnetic field, in the absence of transport currents, is reconsidered from a new mathematical point of view. In particular, we derive a complete set of exact analytical solutions representing all the stationary points (minima and saddle-points) of the relevant Gibbs free-energy functional. The type of these solutions is determined by explicit evaluation of the second variation of the Gibbs free-energy functional. The stable (physical) solutions minimizing the Gibbs free-energy functional form an infinite set and are labelled by a topological number Nv=0,1,2,... Mathematically, they can be interpreted as nontrivial ''vacuum'' (Nv=0) and static topological solitons (Nv=1,2,...) of the sine-Gordon equation for the phase difference in a finite spatial interval: solutions of this kind were not considered in previous literature. Physically, they represent the Meissner state (Nv=0) and Josephson vortices (Nv=1,2,...). Major properties of the new physical solutions are thoroughly discussed. An exact, closed-form analytical expression for the Gibbs free energy is derived and analyzed numerically. Unstable (saddle-point) solutions are also classified and discussed.Comment: 17 pages, 4 Postscript figure

Correlated theory of triplet photoinduced absorption in phenylene-vinylene chains

In this paper we present results of large-scale correlated calculations of triplet photoinduced absorption (PA) spectrum of oligomers of poly-(para)phenylenevinylene (PPV) containing up to five phenyl rings. In particular, the high-energy features in the triplet PA spectrum of oligo-PPVs are the focus of this study, which, so far, have not been investigated theoretically, or experimentally. The calculations were performed using the Pariser-Parr-Pople (PPP) model Hamiltonian, and many-body effects were taken into account by means of multi-reference singles-doubles configuration interaction procedure (MRSDCI), without neglecting any molecular orbitals. The computed triplet PA spectrum of oligo-PPVs exhibits rich structure consisting of alternating peaks of high and low intensities. The predicted higher energy features of the triplet spectrum can be tested in future experiments. Additionally, theoretical estimates of exciton binding energy are also presented.Comment: To appear in Phys. Rev.

Management of young professionals success in the labor market

© 2016, Econjournals. All rights reserved.The relevance of the study is determined by the new socio-cultural situation caused by the development of the information society. The purpose of the article is to identify the relationship between the general cultural competence and professional success of young professionals. The main idea of research is the theory of vocational education’s humanization. The data is given of the author’s sociological survey on the definition of the general cultural level of the students. The authors have developed the principles of management of young professional’s success in the labor market from the perspective of humanization of education. The authors have shown the need to increase the level of common cultural competence among the majority of modern college students, providing a successful self-realization in the labor market. Article Submissions may be useful for developers of the federal state educational standards at all levels of education, teachers and heads of vocational educational institutions and professional higher education institutions, sociologists dealing with youth employment and education

Prediction of infrared light emission from pi-conjugated polymers: a diagrammatic exciton basis valence bond theory

There is currently a great need for solid state lasers that emit in the infrared, as this is the operating wavelength regime for applications in telecommunications. Existing $\pi$--conjugated polymers all emit in the visible or ultraviolet, and whether or not $\pi$--conjugated polymers that emit in the infrared can be designed is an interesting challenge. On the one hand, the excited state ordering in trans-polyacetylene, the $\pi$--conjugated polymer with relatively small optical gap, is not conducive to light emission because of electron-electron interaction effects. On the other hand, excited state ordering opposite to that in trans-polyacetylene is usually obtained by chemical modification that increases the effective bond-alternation, which in turn increases the optical gap. We develop a theory of electron correlation effects in a model $\pi$-conjugated polymer that is obtained by replacing the hydrogen atoms of trans-polyacetylene with transverse conjugated groups, and show that the effective on-site correlation in this system is smaller than the bare correlation in the unsubstituted system. An optical gap in the infrared as well as excited state ordering conducive to light emission is thereby predicted upon similar structural modifications.Comment: 15 pages, 15 figures, 1 tabl

Features of modeling the formation of teaching staff competitiveness

© 2015, Review of European Studies. All right reserved. The state is interested in the formation of teaching staff competitiveness of both higher and secondary vocational education institutions, as it is associated with solving the problems of training competitive specialists for innovative production, increasing the social efficiency of organizations and institutions, economic recovery of the country. In this regard, this article reveals the specifics of modeling the process of the teaching staff competitiveness formation. Major approaches to the study of this problem were the integrative and milieu approaches, a symbiosis of which allows creating competitiveness of the teaching staff, taking into account the features of college educational environment, involving integration of educational, methodological and research activities of teachers; features of professional and interprofessional interaction between members of college teaching staff with staffs of other educational institutions, scientific research institutes, professional community. Specifics of modeling the formation of college teaching staff competitiveness consist in the set of components proposed by the authors (theoretically-methodological, functionally-targeted, substantive, procedural and productive clusters) and in their contents

A theoretical investigation of the low lying electronic structure of poly(p-phenylene vinylene)

The two-state molecular orbital model of the one-dimensional phenyl-based semiconductors is applied to poly(p-phenylene vinylene). The energies of the low-lying excited states are calculated using the density matrix renormalization group method. Calculations of both the exciton size and the charge gap show that there are both Bu and Ag excitonic levels below the band threshold. The energy of the 1Bu exciton extrapolates to 2.60 eV in the limit of infinite polymers, while the energy of the 2Ag exciton extrapolates to 2.94 eV. The calculated binding energy of the 1Bu exciton is 0.9 eV for a 13 phenylene unit chain and 0.6 eV for an infinite polymer. This is expected to decrease due to solvation effects. The lowest triplet state is calculated to be at ca. 1.6 eV, with the triplet-triplet gap being ca. 1.6 eV. A comparison between theory, and two-photon absorption and electroabsorption is made, leading to a consistent picture of the essential states responsible for most of the third-order nonlinear optical properties. An interpretation of the experimental nonlinear optical spectroscopies suggests an energy difference of ca. 0.4 eV between the vertical energy and ca. 0.8 eV between the relaxed energy, of the 1Bu exciton and the band gap, respectively.Comment: LaTeX, 19 pages, 7 eps figures included using epsf. To appear in Physical Review B, 199