Thin films of organic molecular crystals (OMC) possessing type B lattice: spatial structure of dibenzotetraazaannulene film is related to its thickness

Diffractometric and optical measurements showed that at considerable (>200 oK) difference between sublimation temperature and substrate one dibenzotetraazaannulene forms well oriented films structure of which depends on their thickness. This phenomena was explained by assuming that the temperature gradient inside the film can be changed during the evaporation. Therewith, both diffusion processes in clusters and the restructurization of small crystallites were suggested to be important components of OMC film formation mechanism

Methods of cluster analysis in sensor engineering: advantages and faults

We consider the crisp and fuzzy partitioning techniques of cluster analysis bearing in mind their application for classification of data obtained with chemical sensor arrays. The advantage of the cluster analysis techniques is existence of a parameter S(i). This parameter gives quantitative efficiency of classification and can be used as optimization criterion for sensor system as a whole as well as the measurement procedure. The crisp and fuzzy techniques give practically the same result when analyzing the data that cluster uniquely. It is shown that big value of the parameter S(i) is not sufficient for adequate data partitioning into cluster in more complicated cases, and the results of clusterization for the above techniques may diverge. In this case, one should apply both techniques concurrently, checking the correctness of partitioning into clusters against the principal component analysis

Multisensor systems for gas analysis: optimization of arrays for classification of pharmaceutical products

In the present work, the use of the cluster analysis method in the “fuzzy logic” concept for the optimization of the cross-selective sensor arrays (“electronic nose”, EN) is considered. This approach enables to purposefully form the sensor arrays with definite chemical functionality optimized for the solution of the specific applied problems. The criteria of the optimization of the sensor response, number and type of the sensor elements are considered with the goal to improve the classification of widely used pharmaceutical products. The optimization of EN array in the kinetic mode and selection of the most informative part of the sensor response enabled to reduce the analysis time, and also the number of sensors in array, to improve the discriminatory capability of the whole array. Being based on the analysis of response kinetic peculiarities, the physical mechanisms determining the peculiarities of adsorption-desorption processes at the interface have been considered

Raman and Photoluminescence Study of ZnO Films Grown by Chemical Method

In this paper phonon and emission properties of ZnO films grown by metalorganic chemical vapour deposition (MOCVD) at ambient pressure and by molecular beam epitaxy (MBE) are investigated using Raman and photoluminescence (PL) spectroscopy. It is shown that high-frequency shift of non-polar phonon modes corresponds to elastic compressive strain in the plane parallel to c-axis and is equal to 3.2×10−3 and 2.2×10−3 for ZnO film grown by MOCVD and MBE, respectively. The possibility of obtaining highquality ZnO films grown by MOCVD was demonstrated. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3501

A biosensor approach to probe the structure and function of the adsorbed proteins: fibrinogen at the gold surface

The kinetics of adsorption and surface structure of adsorbed layers of the human fibrinogen on the gold surface, determined by Surface Plasmon Resonance (SPR) and Atomic Force Microscopy (AFM) analysis, was employed to probe the lateral distribution and preferred orientation of protein molecules within the monolayer. In this study, special sets of immunoassays are presented for fibrinogen adsorption/conformation analysis. The results show that kinetic parameters of antigen-antibody interactions are directly related to the interfacial conformation of fibrinogen molecules. Various interfacial structures of adsorbed fibrinogen aggregates, namely single, bi- and three- molecular aggregates, were obtained using a combination of AFM imaging and SPR analysis. Adsorption of fibrinogen onto the surface of polycrystalline gold is a complex process including surface-induced unfolding, local self-assembly and adsorption, occurring concurrently with – and on the time scale of – each other. This result confirmed the utility of the proposed approach for detecting the spatial distribution and biofunctional properties of specific proteins adsorbed from biological liquids in biosensors.Просторовий розподіл та переважна орієнтація молекул білків у моношарі досліджена з застосуванням кінетики поверхневого плазмонного резонансу (ППР) та мікроскопії атомних сил (МАС) підчас адсорбції фібріногену людини на поверхню золота. У роботі проведена серія специфічних імунних реакцій щоб проаналізувати адсорбційно-конформаційний стан плівок фібріногену. Отримані результати демонструють прямий звўязок кінетичних параметрів реакції антиген-антитіло з конформацією фібріногену на межі розподілу. Застосування МАС і ППР аналізів дало можливість визначити одно-, двух- та трьох молекулярні структурні сполуки фібріногену на межі розподілу. Адсорбція фібріногену на поверхню полікрісталічного золота - це складний процес, що містить: розгортання, стимульоване поверхнею, само-збирання та адсорбцію, які відбуваються конкурентно у часі. Цей результат підтверджує перспективу запропонованого підходу у біосенсорній техніці для визначення просторового розподілу та біофункціональних властивостей специфічних білків, які адсорбуються з біологічних рідин.Пространственное распределение и преимущественная ориентация молекул белков в монослое изучена с использованием кинетики поверхностного плазмонного резонанса (ППР) и микроскопии атомных сил (МАС) при адсорбции фибриногена человека на поверхность золота. В работе проведена серия специфических имунных реакций для адсорбционо-конформационного анализа пленок фибриногена. Полученные результаты демонстрируют прямую связь кинетических параметров реакции антиген-антитело с конформацией фибриногена на границе раздела. Применение МАК и ППР анализов позволило определить одно-, двух и трех-молекулярные сочетания фибриногена на границе раздела. Адсорбция фибриногена на поверхность поликристаллического золота является сложным процессом, включающим, разворачивание, стимулируемое поверхностью, само-сборку и адсорбцию, происходящим конкурентно во времени. Этот результат подтверждает перспективу предлагаемого подхода в биосенсорной технике для определения пространственного распределения и биофункциональных свойств специфических белков, адсорбируемых из биологических жидкостей

CD150-mediated Akt signalling pathway in normal and malignant B cells

Aim of this article is to study upstream and downstream events in CD150-mediated Akt signaling pathway in normal human B cells, EBV-transformed lymphoblastoid (LCL) and malignant Hodgkin’s lymphoma (HL) B cell lines

Supernova neutrino detection in NOvA

The NOvA long-baseline neutrino experiment uses a pair of large, segmented, liquid-scintillator calorimeters to study neutrino oscillations, using GeV-scale neutrinos from the Fermilab NuMI beam. These detectors are also sensitive to the flux of neutrinos which are emitted during a core-collapse supernova through inverse beta decay interactions on carbon at energies of O(10 MeV). This signature provides a means to study the dominant mode of energy release for a core-collapse supernova occurring in our galaxy. We describe the data-driven software trigger system developed and employed by the NOvA experiment to identify and record neutrino data from nearby galactic supernovae. This technique has been used by NOvA to self-trigger on potential core-collapse supernovae in our galaxy, with an estimated sensitivity reaching out to 10 kpc distance while achieving a detection efficiency of 23% to 49% for supernovae from progenitor stars with masses of 9.6 M☉ to 27 M☉, respectively

Digital aroma technology for chemical sensing: temporal chemical images of complex mixtures

The reliability of Electronic nose applications is mainly based on the sensitivity, repeatability and discernment properties of the sensors composing the array. Due to nature of the chosen sensitive layers, the sensors are particularly suitable to classify environments in which compounds with various chemical functionality play a key role. This article is focusing on the novel strategy aimed at the improving the quality and quantity of chemical information from the sensing instruments based on incorporation kinetic aspects of the array response for perfect formation and improved discrimination of chemical images of the probes. We describe a procedure for reducing both time response and number of elements of gas sensor arrays based on principal component analysis (PCA). Thus, digital aroma technology may be used not only as background for formation of chemical images using intelligent sensor massifs but as well as effective experimental tools for characterization and selection coatings with desired chemical functionality by using time-resolved pattern recognition

Dispersion of natural modes in a many-layer planar system

We derive the recurrence dispersion equations for natural modes of a many-layer planar system. As an illustration a five-layer planar system is considered, and solutions for guided-wave polaritons of such a system are found. The behavior and peculiarities of these solutions are analyzed