Study of the component composition of organic matter of the East Pre-Caucasian basin rocks based on the results of lithological, petrophysical and geochemical studies

This study introduces results of lithological, petrophysical and geochemical investigation of Lower Cretaceous (K1) and Middle Jurassic (J2a-b) rocks of East Pre-Caucasian basin. According to pyrolytic and bituminological studies method of separate determination of kerogen and bitumen concentration been developed. In accordance with this method differentiation of organic matter components in different lithotypes of rocks been described. Also relationship between bitumen and kerogen concentrations been revealed. The majority of samples have poor to fair organic richness and poor source potential. Kerogen type is commonly presented by type III and stages of maturity characterized by stages PC3 to MC3. Bitumen compounds have low concentrations of asphaltenes and aromatic hydrocarbons and mainly contains light and heavy resins. Based on petrophysical and geochemical studies a close relationship between the concentration of organic carbon and the weight concentration of potassium nuclides was obtained. This relationship indicates that kerogen in the sediments under consideration is associated with clay minerals, which is also confirmed by the mineral composition of the rocks.

Arrays of solid contact potentiometric sensors for separate determination of some cephalosporin antibiotics

Arrays of potentiometric sensors including developed solid-contact unmodified and modified sensors based on tetradecylammonium associates with complex compounds of silver (1) and some β-lactam antibiotics (cefazoline, cefuroxime, cefotaxime (n = 3 – 6)) are proposed; polyaniline and copper oxide being modifiers. The main electroanalytic properties of the sensors are determined (the range of the determined concentrations in antibiotic solutions 1 × 10–4 – 0.1 M, 46.3 < S < 48, Cmin = n × 10–5 М, response time 4 – 10 sec, potential drift 4 – 6 mV/day, service life — 2 months). It is shown that modification of the membrane surfaces brings the steepness of the electrode functions to Nernst-values for single-charged ions of the antibiotics under study; reduces the response time and the detection limits, the linearity intervals of the electrode functions being the same. The potentiometric selectivity coefficients of unmodified and modified sensors based on different electrode active components (EAC) to the studied cephalosporins in the presence of interfering antibiotics are close to unity; cross sensitivity parameters for the considered sensors (the average slope of the electrode function of the sensor Sav, the unselectivity factor F, and the reproducibility factor K) are 46.3 < S (mV/pC) < 48; 0.85 < F < 0.90; 144 < K < 170, respectively. Application of sensors in the multisensory analysis of model mixtures of cephalosporin antibiotics is shown. Method of artificial neural networks (ANN) is used for processing of analytical signals. The correctness of the determination is carried out using «spike tests» on the reference model mixtures (the relative error of the determination does not exceed 12 %).

“Electronic tongue” multi-systems for the separate determination of cefotaxime and cefazoline

Electroanalytical properties of unmodified and modified by polyaniline and by CuO nanoparticles solid-contact potentiometric sensors which are based on associates of tetradecylammonium with complex compounds of silver (I) with cephuroxime, cephotaxime and cephazoline Ag(β-lac)2TDA in solutions of corresponding antibiotics were studied. It was revealed that Ag(β-lac)2TDA –based sensors had no specificity to the basic ion but showed sensitivity to other cephalosporins. Taking into account the potentiometric selectivity coefficients and cross-sensitivity parameters of sensors based on different electrode-active components, their use for creating «electronic tongue» multi-sensor systems was shown. Arrays of low-selective potentiometric sensors were created for separate determination of cephazoline and cephotaxime in two-component model mixtures at concentration intervals of 2,5·10-4 – 0,01 М. The method of artificial neural networks was used for processing analytical signals (the relative error of determination not exceeding 13%).

Radioligand binding assay for the simultaneous determination of β1- and β2-adrenergic receptors in human blood cells

Во многих тканях и клетках человека присутствуют как β1-, так и β2-адренорецепторы, информация о содержании и динамике поведения кото- рых часто является клинически значимой. В настоящем исследовании предложена методика раздельного определения обоих типов адреноре- цепторов на основе радиолигандного анализа с использованием 125I-йодоцианопиндолола, включающая проведение трех измерений: 1) без лигандов-конкурентов; 2) в присутствии селективного лиганда ICI 118,551 (0,25 мкМ); 3) в присутствии двух селективных лигандов ICI 118,551 и CGP 20712 (по 0,25 мкМ каждого). Методика протестирована на модельной системе из двух трансгенных линий клеток с экспрессией реком- бинантных β1- и β2-адренорецепторов. При соотношении количества β1-адренорецепторов к β2-адренорецепторам 1:10 погрешность измере- ния составляет около 15%. Анализ 9 клеточных линий, представляющих различные типы клеток крови, показал наличие β2-адренорецепторов в клетках Daudi, Raji, Dami, K-562, HL-60, U-937 и THP-1 и их отсутствие в Т-лимфоцитарных клетках Jurkat и MOLT-4. β1-адренорецепторы достоверно зарегистрированы лишь в клетках THP-1 моноцитарного происхождения. В остальных клетках, за исключением линии Dami, их количество оказалось ниже порога детекции, оцениваемого на уровне 250 молекул на клетку. Измерения, выполненные на мононуклеарных клетках периферической крови здоровых доноров, продемонстрировали присутствие β2-адренорецепторов в диапазоне от 1000 до 2500 моле- кул на клетку, тогда как содержание β1-адренорецепторов во всех случаях находилось на грани или за гранью порога детекции. По-видимому, изучение β1-адренорецепторов в дальнейшем следует проводить на отдельных фракциях клеток крови, в частности на фракции моноцитов β1- and β2-adrenergic receptors are presented in various human tissues and cells, while the information of their content and dynamic behavior is oftenly considered as clinically significant. In this study, a method for the separate determination of both types of adrenoceptors based on radioligand binding analysis using 125I iodocyanopindolol is proposed, comprising three measurements: 1) without competing ligands; 2) in the presence of selective ligand ICI 118,551 (0.25 μM); 3) in the presence of two selective ligands ICI 118,551 and CGP 20712 (0.25 μM each). The technique was tested on a model system of two transgenic cell lines with the expression of recombinant β1- and β2-adrenergic receptors. If the ratio of the number of β1-adrenergic receptors to β2-adrenergic receptors is 1:10, the measurement error is about 15%. Analysis of 9 cell lines representing different types of blood cells showed the presence of β2-adrenergic receptors in Daudi, Raji, Dami, K-562, HL-60, U-937 and THP-1 cells and their absence in Jurkat and MOLT-4 cells. β1-adrenergic receptors are reliably registered only in THP-1 cells of monocytic origin. In the remaining cell lines, with the exception of Dami, the number of β1-adrenergic receptors was found below the detection limit, estimated as 250 molecules per cell. Measurements performed on the peripheral blood mononuclear cells of healthy donors showed the presence of β2-adrenergic receptors in the range from 1000 to 2500 molecules per cell, while the content of β1-adrenergic receptors in all cases appeared to be on the border or beyond the detection limit. Apparently, further study of β1-adrenergic receptors should be performed on the blood cells isolated fractions, on monocytes in particular

Optimization of the Conditions for Determining 2,4-D and Deltamethrin by HPLC

The paper presents the results of optimizing the conditions for the chromatographic determination of 2,4-dichlorophenoxyacetic acid and deltamethrin for two capillary columns (Supelcosil LC-18, Kromasil C-18). The modes of individual chromatography of pesticides were selected. The use of the isocratic elution mode in the joint presence of 2,4-dichlorophenoxyacetic acid and deltamethrin was shown and experimentally proved to be invalid. Three options were proposed for the conditions of the gradient mode of the separate detection of analytes in a mixture. The developed technique for the chromatographic separate determination of 2,4-D and deltamethrin with their joint presence was tested via analysis of river water and potato samples.

High-sensitive separate determination of the group of triazine pesticides in drinking water by the method of high performance liquid chromatography with tandem mass-spectrometrical detection

Introduction. The modern highly sensitive methods of controlling substances that affect humans in real environmental conditions are necessary to adequately assess the quality and chemical safety of drinking water, including pesticides used in agriculture for the destruction of weeds and pests. The aim of the work was to improve the sensitivity of existing techniques for the determination of triazine pesticides in their joint presence to control drinking and bottled water. Material and methods. The studies were performed using a chromatography mass-spectrometric system including a liquid chromatography with tandem mass-spectrometric triple quadrupole detector. Results. The influence of various factors on the extraction of triazine pesticides from water has been studied, the chromatographic and detection conditions have been optimized. Linearity in the range of 0.1 - 10 μg / dm3 is proved. The limits of detection and quantitative determination of triazine pesticides in drinking water are established in accordance with hygienic standards. Discussion. The procedure allows separate determination of triazine pesticides when they are co-located in concentrations at and below the corresponding MPC values in drinking and bottled water. The method allows reliably determining the target compounds without the use of hard-to-reach deuterated reference materials. To improve the reliability of the method, as an internal standard it is recommended to use one of the compounds studied, which is not a widely used pesticide, for example, propazine, with mandatory control of the initial matrix for its content. Conclusion. A highly sensitive method for the separate determination of a group of triazine pesticides (simazine, atrazine, propazine, prometrin, metribuzin, metamitron) was developed with their joint presence in drinking water with sensitivity at or below the corresponding hygienic standards.

High-sensitive separate determination of the group of triazine pesticides in drinking water by the method of high performance liquid chromatography with tandem mass-spectrometrical detection

Introduction. The modern highly sensitive methods of controlling substances that affect humans in real environmental conditions are necessary to adequately assess the quality and chemical safety of drinking water, including pesticides used in agriculture for the destruction of weeds and pests. The aim of the work was to improve the sensitivity of existing techniques for the determination of triazine pesticides in their joint presence to control drinking and bottled water. Material and methods. The studies were performed using a chromatography mass-spectrometric system including a liquid chromatography with tandem mass-spectrometric triple quadrupole detector. Results. The influence of various factors on the extraction of triazine pesticides from water has been studied, the chromatographic and detection conditions have been optimized. Linearity in the range of 0.1 - 10 μg / dm3 is proved. The limits of detection and quantitative determination of triazine pesticides in drinking water are established in accordance with hygienic standards. Discussion. The procedure allows separate determination of triazine pesticides when they are co-located in concentrations at and below the corresponding MPC values in drinking and bottled water. The method allows reliably determining the target compounds without the use of hard-to-reach deuterated reference materials. To improve the reliability of the method, as an internal standard it is recommended to use one of the compounds studied, which is not a widely used pesticide, for example, propazine, with mandatory control of the initial matrix for its content. Conclusion. A highly sensitive method for the separate determination of a group of triazine pesticides (simazine, atrazine, propazine, prometrin, metribuzin, metamitron) was developed with their joint presence in drinking water with sensitivity at or below the corresponding hygienic standards.

Application of Neural Networks in the Problem of Quantitative Analysis of Air Composition

Purpose of reseach is to develop a method for generating training data to enable the use of artificial neural networks (ANN) method in gas analyzer systems. The problem of increasing the accuracy of separate determination of gas concentrations in multicomponent mixtures under conditions of environmental parameters changes is considered. It is proposed to increase the accuracy of determining target gas concentrations by using the ANN method for joint processing of sensor signals.Methods: Training data for the neural network were generated using numerical experiments and mathematical simulation methods. To assess the accuracy of training, the standard deviation (SD) was used and the relative error was calculated. ANN training and research were conducted in the MATLAB environment (the Neural Networks Toolbox application). When developing mathematical models of gas sensors, the theory of electrical circuits, electronic theory of chemisorption and the adsorption theory of heterogeneous catalysis were applied.Results: A method for generating training data sets using mathematical models of gas sensors is described. The proposed training method has been tested on a specific task, in particular, a decision-making device based on ANN for a four-component gas analyzer has been developed. The efficiency of using neural networks for tuning out from the mutual cross-sensitivity of sensors was evaluated.Conclusion: A method for generating training data using simulation models is proposed, which allows automazing the process of training, research, choosing the architecture and structure of ANN and their testing. The method was tested. Based on the analysis of the obtained errors, conclusions are made about the efficiency of using neural networks to reduce errors caused by cross sensitivity at different concentrations of the main and interfering gases.

Coupling of Reactive Power Planning for Operation and Voltage Stability Enhancement

The ongoing decommissioning of conventional power plants decreases the installed reactive power reserves for voltage control in transmission grids. Hence, an efficient planning of compensation devices substituting this lack of reactive power is required. Grid operators must allocate these devices for steady-state voltage control and for dynamic voltage control ensuring voltage stability. A separate determination of this static and dynamic VAR demand, however, fails to exploit synergies and disregards that VAR compensation in steady-state reduces the reserves for dynamic compensation. This paper proposes a coupled determination of the system static and dynamic VAR demand. An optimisation method applying mixed-integer programming identifies an efficient allocation and portfolio consisting of different compensation technologies. It includes constraints for voltage limits during steady-state and contingencies as well as for long-term voltage stability. Results emphasise that the method identifies an efficient portfolio for various operation and fault scenarios, while providing the required voltage stability margin.

Coupling of Reactive Power Planning for Operation and Voltage Stability Enhancement

The ongoing decommissioning of conventional power plants decreases the installed reactive power reserves for voltage control in transmission grids. Hence, an efficient planning of compensation devices substituting this lack of reactive power is required. Grid operators must allocate these devices for steady-state voltage control and for dynamic voltage control ensuring voltage stability. A separate determination of this static and dynamic VAR demand, however, fails to exploit synergies and disregards that VAR compensation in steady-state reduces the reserves for dynamic compensation. This paper proposes a coupled determination of the system static and dynamic VAR demand. An optimisation method applying mixed-integer programming identifies an efficient allocation and portfolio consisting of different compensation technologies. It includes constraints for voltage limits during steady-state and contingencies as well as for long-term voltage stability. Results emphasise that the method identifies an efficient portfolio for various operation and fault scenarios, while providing the required voltage stability margin.