Identification and Comparative Analysis of Alkaloids by Inversion Voltammetry Method

2019 ◽  
pp. 113-121
Author(s):  
V.A. Semenova ◽  
E.M. Petrenko
Keyword(s):  
Electronic Tongue ◽  
Small Mass ◽  
Test System ◽  
Complex Compounds ◽  
Electrochemical Test ◽  
Form Complex ◽  
New Approach ◽  
Psychotropic Substances ◽  
Detection And Identification ◽  
Inversion Voltammetry

The alkaloids concurrent detection and identification in the samples by the method of multisensory inversion voltammetry is the purpose of the work. To achieve this goal, the proposed method has been substantiated, the composition of the electrochemical test system has been optimized taking into account the specifics of the detected substances, and informative signs that characterize the presence of alkaloids in the studied sample have been found. A new approach, consisting in the use of an electrochemical multisensor test system in the form of a solution containing a set of metal ions that can form complex compounds with organic substances, has been developed and scientifically approved. The results showed that each organic substance has a different effect on the electrochemical behavior of the multisensory test system. The use of such a test system made it possible to model the principle currently defined by the term "Electronic tongue". An electronic database has been prepared according to the results of the electroanalytical studies, which made it possible to identify the detected substance by comparing it with analyzed sample. The proposed electrochemical method, which is based on multisensor inversion voltammetry, allows the detection and identification of both narcotic drugs and psychotropic substances with high confidence for a small mass of the sample.

Determination of the Concentration of Organic Compounds using an Electrochemical Test System

2019 ◽  
pp. 117-123
Author(s):  
N.V. Lukovtseva ◽  
V.A. Semenova ◽  
V.P. Lukovtsev ◽  
K.N. Bobov ◽  
E.M. Petrenko
Keyword(s):  
Organic Matter ◽  
Organic Compounds ◽  
Experimental Studies ◽  
Test System ◽  
Organic Substances ◽  
Vector Representation ◽  
Electrochemical Test ◽  
Specific Test ◽  
Form Complex ◽  
The Difference

The research paper looks at the possibility of using an electrochemical test system to determine the concentration of organic compounds. The experiments were based on the fact that each class of organic substances required a specific test system. Since we were interested in sulfurcontaining organic compounds, the electrochemical test system was a solution containing cations of zinc, gallium, and copper. These metals can form complex compounds with sulfur-containing organic substances. When inserted into such a test system, organic substances of this class significantly alter its electrochemical behavior, which is reflected in stripping voltammograms. The experimental procedure and software made it possible to obtain the required number of parameters, which enabled a multisensory analysis on a single working (indicative) electrode. The stripping voltammograms recorded before and after addition of organic matter to the electrochemical test system were digitized; then one voltammogram (recorded when the test system contained no admixtures) was deducted from the other one (recorded when organic matter was added to the test system). The resulting difference curve was divided into segments; experiments showed that the number of segments should not exceed 20 or 30. These digitized curved sections were integrated in order to obtain a set of informative parameters, which can be viewed as a set of vectors, i.e., a multi-dimensional vector representation of each analyte. To visualize the results of the electroanalytical study, we represent the multidimensional image of organic substances of various concentrations as a number of vectors arranged in a circlel; the number of vectors corresponds to the number of sections of the difference curves in each experiment. The results show that the length of the vectors characterizing the difference curves decreases as the concentration of the analyzed organic matter decreases. In the limit, the curve visualizing organic matter with zero concentration takes the form of a circle, which indicates that there are no deviations from the stripping voltammogram of the electrochemical test system. Therefore, it can be concluded that the electrochemical test system can be certainly used for determining the concentration of organic compounds, producing quite reliable estimated results. This conclusion is confirmed by comparing the vector representation of analytes with the vector representations of organic substances of different concentrations, which constitute the database containing the results of experimental studies. Such a comparison is given in the form of a histogram reflecting the degree of proximity of the vector representation of the analyzed organic matter to substances from the database based on an estimate of Euclidean distances between the corresponding multidimensional vectors.

scholarly journals Electrochemical Test System for Analysis of Sulfur-Containing Organic Substances

2019 ◽  
pp. 88-95 ◽  
Author(s):  
V.P. Lukovtsev ◽  
N.V. Lukovtseva ◽  
V.A. Semenova
Keyword(s):  
Organic Compounds ◽  
Test System ◽  
Oil Refining ◽  
Organic Substances ◽  
Electrochemical Test ◽  
Form Complex ◽  
Experimental Data Processing ◽  
Study Results ◽  
Vector Representations ◽  
Sulfur Containing

The paper discusses selection of a set of metals for an electrochemical test system used for the detection of sulfur-containing organic substances. Analytical studies of organic sulfur compounds are very important since these compounds are widely used in medicine, biology, oil refining industry, etc. Quantitative determination and identification of sulfur-containing substances is essential for solving environmental problems. The electrochemical test system for analysis of organic substances is a solution containing a set of cations of various metals that have the ability to form complex compounds with analytes. Thereby, a single electrode can be used to carry out electrochemical multisensory analysis because metal cations play the role of sensors. Thus, there is no need to use a set of several working (indicator) electrodes, the number of which determines the number of informative parameters. Since sets of metals for test systems may slightly differ from each other, we need to select an optimal set for a specific problem. According to the study results, a set of metals for sulfur-containing organic substances consists of zinc, gallium and copper. The test system composed of these metals gives reliable results of electroanalytical determination of organic compounds of this class. The expediency of using such a test system is confirmed by comparative estimation of the Euclidean distances between the vector representations of the analytes and sulfur-containing organic compounds presented in the previously created database. Software for experimental data processing, visualization, and comparative analysis of the vector representations and the database components is developed.

scholarly journals New N-(oxazolylmethyl)-thiazolidinedione Active against Candida albicans Biofilm: Potential Als Proteins Inhibitors

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2522 ◽  
Author(s):  
Gabriel Marc ◽  
Cătălin Araniciu ◽  
Smaranda Oniga ◽  
Laurian Vlase ◽  
Adrian Pîrnău ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Infection Prevention ◽  
Public Health Problem ◽  
Opportunistic Pathogen ◽  
Surface Proteins ◽  
Form Complex ◽  
New Approach ◽  
New Class ◽  
New Compounds

C. albicans is the most frequently occurring fungal pathogen, and is becoming an increasing public health problem, especially in the context of increased microbial resistance. This opportunistic pathogen is characterized by a versatility explained mainly by its ability to form complex biofilm structures that lead to enhanced virulence and antibiotic resistance. In this context, a review of the known C. albicans biofilm formation inhibitors were performed and a new N-(oxazolylmethyl)-thiazolidinedione scaffold was constructed. 16 new compounds were synthesized and characterized in order to confirm their proposed structures. A general antimicrobial screening against Gram-positive and Gram-negative bacteria, as well as fungi, was performed and revealed that the compounds do not have direct antimicrobial activity. The anti-biofilm activity evaluation confirmed the compounds act as selective inhibitors of C. albicans biofilm formation. In an effort to substantiate this biologic profile, we used in silico investigations which suggest that the compounds could act by binding, and thus obstructing the functions of, the C. albicans Als surface proteins, especially Als1, Als3, Als5 and Als6. Considering the well documented role of Als1 and Als3 in biofilm formation, our new class of compounds that target these proteins could represent a new approach in C. albicans infection prevention and management.

Polarization of Ti6Al4V alloy in NaBr electrolyte and surface fractal analysis

2016 ◽  
Vol 232 (7) ◽  
pp. 602-609
Author(s):  
Yafeng He ◽  
Wenzhuang Lu ◽  
Weiming Gan ◽  
Jianshe Zhao ◽  
Dunwen Zuo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Titanium Alloy ◽  
Electrochemical Machining ◽  
Test System ◽  
Surface Topology ◽  
Electrochemical Test ◽  
Polarization Characteristics ◽  
The Relationship ◽  
Scanning Electron

Electrochemical machining is a promising method for titanium alloy processing. The polarization characteristics of Ti6Al4V were studied in detail in order to provide a deeper understanding of this method. The polarization curve of the alloy, which shows the relationship between current density and potential under an external electric field, was obtained in NaBr electrolyte at three different concentrations in a three-electrode electrochemical test system. The surface topography of the polarization zone and pits was examined by scanning electron microscopy, and their fractal features were calculated by the picture point cover method. The results show that Ti6Al4V in the more concentrated electrolyte has higher dissolution rate, lower decomposition potential, and more uniform surface topology in the polarization areas.

Approximate Velocities in Mixed Exact-Approximate Position Synthesis of Planar Mechanisms

1999 ◽  
Vol 123 (3) ◽  
pp. 388-394 ◽  
Author(s):  
Jennifer E. Holte ◽  
Thomas R. Chase ◽  
Arthur G. Erdman
Keyword(s):  
Two Dimensional ◽  
Computer Implementation ◽  
Motion Generation ◽  
Planar Mechanisms ◽  
Form Complex ◽  
New Approach ◽  
Realistic Representation ◽  
Velocity Constraints ◽  
Position Synthesis ◽  
Exact Positions

A new approach to the synthesis of planar linkage mechanisms with approximate velocity constraints is proposed. The paper presents the first closed-form complex-number dyad solution to the ground pivot specification problem for two precision positions with velocity specified at one of the positions. The solution is then manipulated in order to add approximate velocity constraints to design methods for two exact positions and an unlimited number of approximate positions. The approximate position and velocity constraints facilitate more realistic representation of design objectives. Solution spaces are presented using two-dimensional ground-pivot maps. Computer implementation of the proposed methodologies would allow designers with little or no knowledge of the synthesis techniques to interactively explore maps of solutions for four-bar motion generation.

scholarly journals REDUCTION OF TRUE POWER LOSS BY IMPROVED ALGORITHM

2018 ◽  
Vol 6 (8) ◽  
pp. 105-113
Author(s):  
K. Lenin
Keyword(s):  
Optimization Algorithm ◽  
Power Loss ◽  
Reactive Power ◽  
Test System ◽  
New Approach ◽  
Real Power ◽  
Brain Storm Optimization ◽  
Course Of Action ◽  
Simulation Results ◽  
Power Problem

This paper proposes Improved Brain Storm Optimization (IBSO) algorithm is used for solving reactive power problem. predictably, optimization algorithm stimulated by human being inspired problem-solving procedure should be highly developed than the optimization algorithms enthused by collective deeds of ants, bee, etc. In this paper, a new Improved brain storm optimization algorithm defined, which was stimulated by the human brainstorming course of action. In the projected Improved Brain Storm Optimization (IBSO) algorithm, the vibrant clustering strategy is used to perk up the k-means clustering process & exchange of information wrap all ideas in the clusters to accomplish suitable searching capability. This new approach leads to wonderful results with little computational efforts. In order to evaluate the efficiency of the proposed Improved Brain Storm Optimization (IBSO) algorithm, has been tested standard IEEE 30 bus test system and compared to other standard reported algorithms. Simulation results show that Improved Brain Storm Optimization (IBSO) algorithm is superior to other algorithms in reducing the real power loss.

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