bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving work outcomes in audit firms: the mediating role of perceived organizational support
Authors: Barrainkua Aroztegi Itsaso , Aldazabal Etxeberria M. Edurne , Espinosa-Pike Marcela
Published: July 2024

This study analyses the influence of role overload on organizational commitment and job satisfaction in audit firms, as well as the mediating role of perceived organizational support on these job outcomes. This study is based on 122 survey responses from Spanish auditors. The results show that role overload has a negative relationship with organizational commitment and job satisfaction. Moreover, our findings demonstrate that perceived organizational support mediates both the relationship between role overload and organizational commitment, and the relationship between role overload and job satisfaction. To the best of our knowledge, this is the first study to analyse the role played by organizational support in the relationship between role overload and auditors’ critical work outcomes. Time constraints and heavy workloads are often perceived as inherent features of an auditor’s job. This particular organizational context makes it necessary to identify variables within a firm’s purview, such as organizational support, which may contribute to mitigating the negative effect of role overload on auditors’ job attitudes.

Este estudio analiza la influencia de la sobrecarga de trabajo en el compromiso organizativo y la satisfacción laboral en las firmas de auditoría, así como el papel mediador del apoyo percibido por la organización en las actitudes laborales de los auditores. Este estudio se basa en una encuesta realizada a 122 auditores españoles. Los resultados muestran que la sobrecarga de trabajo tiene una relación negativa con el compromiso organizativo y la satisfacción laboral. Asimismo, nuestros resultados demuestran que el apoyo percibido por la organización media el efecto negativo de la sobrecarga de trabajo tanto en el compromiso organizativo como en la satisfacción laboral. Este es el primer estudio que analiza el papel del apoyo percibido por la organización en la relación entre la sobrecarga de trabajo y las actitudes laborales de los auditores. Las limitaciones de tiempo y el exceso de trabajo a menudo se perciben como características inherentes del trabajo de un auditor. El particular contexto organizativo de la auditoría resalta la importancia de identificar variables, tales como el apoyo percibido por la organización, que se encuentren dentro del marco de actuación de las firmas de auditoría y que pueden contribuir a mitigar el efecto negativo de la sobrecarga de trabajo en las actitudes laborales de los auditores.
MATHEMATICAL MODELING AND EVALUATION OF THERMODYNAMIC PERFECTION OF A CHEMICAL REACTOR
Authors: Andreev Aleksandr S. , Aksenchik Konstantin V.
Published: July 2024

The development of a formalized mathematical model for quantitative and qualitative assessment of the thermodynamic perfection of a gas chemical reactor is described in the article. The reactor was considered as an energy technology system, that is, in the unity of the transformation of matter and energy. Mathematical modeling and evaluation of the thermodynamic perfection of a chemical reactor is generalized to a class of known chemically active gas systems characteristic of ammonia synthesis, sulfur dioxide oxidation, methanol synthesis, nitric oxide oxidation, etc. The equilibrium degree of transformation of a substance and exergy are taken as the determining parameters for modeling and evaluating the thermodynamic perfection of a chemical reactor. These parameters are functions of temperature and reflect the opposing tendencies of the process when it changes, the evaluation of which allows us to quantify the finding of the maximum exergy in the coordinates (E-T) when justifying the optimal temperatures of the process. The model was tested on a specific example of a sulfur dioxide oxidation reactor in the production of sulfuric acid. The public Octave programming environment was used for computer modeling. The developed mathematical model is recommended to be used in the operational preparation and optimization of the initial data for the design of gas reactors. The mathematical model can be supplemented with a mathematical model developed by the authors earlier for quantifying the current profile of the degrees of transformation of the target component of a chemically active reactive gas mixture in the course of its movement in a polytropic tubular reactor of the "pipe in a pipe" type. After testing and setting up the model in practice, it can be used in an automated control system for chemical reactors, including when creating adaptive control systems.
For citation:
Andreev A.S., Aksenchik K.V. Mathematical modeling and evaluation of thermodynamic perfection of a chemical reactor. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 5. P. 114-120. DOI: 10.6060/ivkkt.20246705.6964.
INVESTIGATION OF SOLVATION IN LITHIUM PERCHLORATE -PROPYLENE CARBONATE-DIMETHYL CARBONATE SYSTEM BY RAMAN SPECTROSCOPY
Authors: Rabadanov Kamil Sh. , Malik M.Gafurov Malik M. , Akhmedov Magomed A. , Rabadanova Dzhennet I. , Magomedova Asiyat G.
Published: July 2024

The difference of solvent properties can significantly affect the solvation phenomena in individual and, especially, in mixed solutions. In particular, it can be assumed that in mixed solvents, i.e. in systems with intermediate dielectric permittivity (mixtures of linear and cyclic carbonic acid esters), cations will bind molecules of linear esters more strongly and bind molecules of cyclic esters more weakly than it takes place in individual solvents. In the present work the Raman spectra of lithium perchlorate solvents in propylene carbonate (PC), dimethyl carbonate (DMC) and their mixture in a wide range of salt concentrations are studied. It is shown that the solvation effects of the cation are clearly traced in the region of symmetric ring vibrations (~690-730 cm-1) of propylene carbonate and in the region of deformation vibrations of CCA (~520 cm-1) of dimethyl carbonate. These effects are also evident in the mixed solvent. The so-called method of differential spectroscopy was used to judge the structural changes of mixed-solvent systems. It consisted in constructing spectra of lithium salt solutions in mixed solvents, additive sum of spectra of lithium salt solutions in PC and DMC, as well as their difference (differential spectra). The analysis of differential spectra allows us to conclude that in systems with mixed solvent there is a weakening of interaction of propylene carbonate molecules with ions, and there is a preferential solvation of cations and anions by dimethyl carbonate molecules. Also, unlike propylene carbonate, dimethyl carbonate solvates perchlorate ions, which follows from the line contour changes in the region of CH3-group vibrations (2970 cm-1) solvation of anions is also observed in the mixed solvent.
For citation:
Rabadanov K.Sh., Gafurov M.M., Akhmedov M.A., Rabadanova D.I., Magomedova A.G. Investigation of solvation in lithium perchlorate -propylene carbonate-dimethyl carbonate system by raman spectroscopy. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 5. P. 36-42. DOI: 10.6060/ivkkt.20246705.6967.
INTERACTION OF (4E)-3-ALKYL(BENZYL)AMINO-4-(HYDROXYIMINO)NAPHTHALENE-1(4H)-ONES WITH 2,2-DIHYDROXY-1,3-INDANEDIONE
Authors: Gornostaev Leonid M. , Rudenko Daria S. , Kirik Sergey D. , Krasnov Vyacheslav I.
Published: July 2024

Many natural and synthetic quinone, including naphthoquinone derivatives, have some valuable properties. They are known as dyes, antibiotics, vitamins, and antioxidants. Some naphthoquinone derivatives act as cytostatic and antitumor reagents. However, the reduction of the quinoid fragment to the semiquinone radical and, as a consequence, the formation of toxic anion radicals, makes these substances cardiotoxic. The replacement of one or both carbonyl groups with the imino fragment can be one of the ways to solve this problem because iminoquinones have a weak redox cycle. This paper presents the results of the MTT test (primary screening for antitumor activity) of some 3-arylamino-1,4-naphthoquinone-4-oximes which were synthesized earlier. It has been shown that (4E)-4-(hydroxyimino)-3-(p-ethoxyphenylamino)naphtho-1(4H)-one and (4E)-4-(hydroxyimino)-3-(p-tolylamino)naphtho-1(4H)-one are most active against the colon adenocarcinoma and chronic myeloid leukemia in the tumor cell lines, respectively. We have performed the oximation reaction of 2-alkyl(benzyl)amino-1,4-naphthoquinones with hydroxylamine in ethanol to obtain a series of (4E)-3-alkyl(benzyl)amino-4-(hydroxyimino)naphthalene-1(4H)-ones. The reactions of synthesized products with 2,2-dihydroxy-1,3-indanedione (ninhydrin) have been studied under various conditions, i.e., in acetic acid under moderate heating and in dimethyl sulfoxide in the presence of methanesulfonic acid at different temperatures. It has been demonstrated that the interaction of (4E)-3-alkyl(benzyl)amino-4-(hydroxyimino)naphthalene-1(4H)-ones with ninhydrin in acetic acid leads to (6E)-5-alkyl(benzyl)amino-6-гhudroxyimino-4b,11b-dihydroxy-4b,5-dihydrobenzo[f]indeno[1,2-b]indol-11,12(6H,11bH)-diones. More severe conditions (dimethyl sulfoxide, methanesulfonic acid, and heating) leads to a mixture of products, the main of which are 1–alkyl-3'H-spiro[benzo[f]indole-2,1’-isobenzofuran]-3,3’,4,9(1H)-tetraones and 13-alkyl(benzyl)benzo[f]isochromeno[4,3-b]indole-5,7,12(13H)-triones. The yields of the products depend on the chosen temperature regime of the reaction. The structure of all synthesized compounds is confirmed by the physico-chemical methods, i.e., 1H and 13C NMR spectroscopy, IR spectroscopy, high-resolution mass spectrometry, spectrophotometry and elemental analysis.
For citation:
Gornostaev L.M., Rudenko D.S., Kirik S.D., Krasnov V.I. Interaction of (4E)-3-alkyl(benzyl)amino-4-(hydroxyimino)naphthalene-1(4H)-ones with 2,2-dihydroxy-1,3-indanedione. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 5. P. 24-35. DOI: 10.6060/ivkkt.20246705.7015.
INFLUENCE OF HEAT TREATMENT ON THE CORROSION PROPERTIES OF WE43 MAGNESIUM ALLOY DOPED WITH RARE EARTH ELEMENTS
Authors: Paspelau Andrei V. , Kasach Aliaksandr A. , Kurilo Irina I. , Tsyganov Aleksandr R.
Published: July 2024

This paper investigates the impact of heat treatment (T5) on the structure of magnesium alloy WE43. The study employs physicochemical research methods, including scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray phase analysis.  The results indicate that the surface of WE43 alloy exhibits a reticulated microstructure consisting of α-Mg and β-Mg phases that contain rare-earth elements (Y - up to 3.7 wt.%; Nd - up to 1.1 wt.%). The microstructure of heat-treated alloy WE43-T5 comprises of α-Mg phase and evenly distributed phases of globular and plate-like forms. The studied samples exhibit contrasting regions related to metallic phases of alloying elements (Mg41Nd5, Mg12Nd, Mg5Gd, MgY, Mg24Y5). The corrosion behavior of WE43 and WE43-T5 alloys was studied in model solutions that simulate the bone tissue environment using a set of electrochemical methods. The solutions used were Hank's solution with a pH of 7.4 and acidified Hank's solution with a pH of 5.0, which corresponds to the injured state of bone tissue. The study focused on the effects of heat treatment on the corrosion of magnesium alloys. The study found that the heat treatment process of magnesium alloy WE43 reduced the corrosion rate by 4.4 times and 2.7 times in Hank's solutions with pH 7.4 and pH 5.0, respectively. The exponential values n1 and n2 are shown to be in the range 0.81 to 0.97. Values close to 1 indicate that the constant phase element models the impedance of the distributed capacitive element. Heat treatment results in a 2.5-fold increase in the polarization resistance of the WE43 alloy in Hank's solution (pH=7.4). However, in Hank's solution (pH=5.0), the polarization resistance of the heat-treated alloy decreases by 68%. The Rp values of WE43 and WE43-T5 samples in Hank's solution (pH=5.0) are similar.
For citation:
Paspelau A.V., Kasach A.A., Kurilo I.I., Tsyganov А.Р. Influence of heat treatment on the corrosion properties of we43 magnesium alloy doped with rare earth elements. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 5. P. 128-135. DOI: 10.6060/ivkkt.20246705.7076.
OPTIMIZATION OF THE SYNTHESIS METHOD FOR VITAMIN A NANOEMULSIONS
Authors: Gvozdenko Alexey A. , Blinov Andrey V. , Golik Alexey B. , Rekhman Zafar A. , Kolodkin Maxim A. , Oblogin Yaroslav A. , Kuznetsov Egor S.
Published: July 2024

The article presents the results of optimizing the procedure for the synthesis of vitamin A nanoemulsions. For the synthesis of nanoemulsions, vitamin A and Tween 80 were mixed, distilled water was added to the resulting mixture and mixed with a dispersant. To optimize the method for synthesizing vitamin A nanoemulsions, a multifactorial experiment was carried out, which included 4 input parameters. As input parameters, we considered the stirring speed, stirring time, the content of the dispersed phase, the content of fat-soluble vitamin A in the dispersed phase. The average hydrodynamic radius of vitamin A micelles was used as an output parameter. As a result of the studies, ternary surfaces of the dependence of the average hydrodynamic radius of vitamin A micelles on the parameters of nanoemulsion synthesis were obtained. It was found that all samples have a monomodal size distribution. The analysis of the data obtained made it possible to establish that the average hydrodynamic radius of vitamin A micelles is significantly affected by all the studied parameters. The optimal parameters for the synthesis of vitamin A nanoemulsions have been established: stirring speed (ν) - from 17000 to 22500 rpm, mixing time (τ) - from 180 to 270 s, content of the dispersed phase (ω (dispersed phase) - from 1 to 4%, the content of fat-soluble vitamin A in the dispersed phase (ω (vitamin A)) is from 50 to 70%. The nanoemulsion sample obtained with these parameters has an average hydrodynamic micelle radius of 62 ± 13 nm.
For citation:
Gvozdenko A.A., Blinov A.V., Golik A.B., Rekhman Z.A., Kolodkin M.A., Oblogin Y.A., Kuznetsov E.S. Optimization of the synthesis method for vitamin A nanoemulsions. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 6. P. 94-99. DOI: 10.6060/ivkkt.20246706.6966.
PREDICTION OF ELECTROCHEMICAL PROCESSES OF LOCAL DISSOLUTION OF STAINLESS STEELS. PART 2. ANALYTICAL AND SIMULATION MODELING OF PROCESS DYNAMICS
Authors: Vinogradova Svetlana S.
Published: July 2024

To analyze the process of pitting corrosion, a state graph was used, which displays the possible states of local dissolution of chromium-nickel steels, taking into account the additional state "unstable passivation of macropitting". The developed analytical model for calculating the process before the formation of stable pitting is based on homogeneous Markov chains. The calculation of conditional probabilities of system changes from one possible state to another determines the time in the VisualStudio 2010 environment on the platform of NetFramework using the C# programming language. A comparison of the calculation of states with “unstable passivation of macropitting” (UPM) and without it allowed us to establish for stainless steels (12X18N10T, 10X17N13M2T, 08X22N6T) that the formation time of stable pitting taking into account UPM is less than the formation time without it, but more for 08X22N6T steel, which is due to the increased chromium content in its composition. A simulation model (SM) has been created, which is based on the Monte Carlo method, in which a random number generator is used to implement random processes of local dissolution due to SM, a sequence of states in which the system is located before its transition to a stable state is obtained. Also, due to this model, it became possible to consider the change in the potential of the system in the process of local dissolution of the studied steels. The use of two modeling approaches taking into account the state of the UPM allowed us to establish that IT is better consistent with experimental results both on a quantitative and qualitative level. An algorithm for selecting the values of the mode parameters is proposed, which became the basis for predicting the formation of macropitting processes.
For citation:
Vinogradova S.S. Prediction of electrochemical processes of local dissolution of stainless steels Part 2. Analytical and simulation modeling of process dynamics. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 6. P. 119-126. DOI: 10.6060/ivkkt.20246706.6972.
STUDY OF THE INFLUENCE OF MODIFIERS ON THE HYDRATION OF CEMENT BY THE METHOD OF ISOTHERMAL CALORIMETRY
Authors: Usacheva Tatiana R. , Krainova Anastasia A. , Vinogradova Lyubov A. , Oganyan Violetta V. , Kokurina Galina N. , Myshenkov Mikhail S. , Anufrikov Yuri A. , Shasherina Anna Yu. , Adamtsevich Alexey O.
Published: July 2024

The effect of modifiers on the hydration of cements was studied by isothermal calorimetry. Thermochemical experiments were carried out using a TAM III isothermal calorimeter (TA Instruments). For the TAM III calorimeter, a method was developed for conducting experiments on monitoring the thermal activity of solid-phase samples with the possibility of repeated use of steel ampoules with a volume of 20 ml. The processes of hydration of Portland cement grade CEM I 42.5B D0 LLC "Holcim Rus" without a modifier and with modifiers polycarboxylate type S (POLYPLAST LLC and «Glass Powder) were studied. Heat release thermograms were recorded, which showed good reproducibility of the results and their similarity with those available in the literature for similar studies carried out according to standard methods using a TAM AIR isothermal calorimeter (TA Instruments). This indicates the reliability of the obtained data and the possibility of using the method proposed in this article to study the processes of hydration of cements. The maximum heat release on the thermograms of samples with a polycarboxylate modifier is observed approximately 20 h after the start of heat release monitoring. Samples without the modifier and with the glass powder modifier show the maximum heat release approximately 10 h after the start of the experiment. Analysis of the results showed that the presence of modifiers leads to increased heat release during cement hydration in relation to its initial composition. Accordingly, it takes less time to complete hydration. However, it is also necessary to take into account the possible risks of violation of the technological modes of operation of the corresponding equipment due to excessive heat release during the hydration of modified cements.
For citation:
Usacheva T.R., Krainova A.A., Vinogradova L.A., Oganyan V.V., Kokurina G.N., Myshenkov M.S., Anufrikov Yu.A., Shasherina A.Yu., Adamtsevich A.O. Study of the influence of modifiers on the hydration of cement by the method of isothermal calorimetry. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 6. P. 88-93. DOI: 10.6060/ivkkt.20246706.6979.
SYNTHESIS OF POLYACRYLAMIDE HYDROGELS WITH PORPHYRIN FRAGMENTS IN THE SIDE CHAIN IN THE PRESENCE OF IMIDAZOLIUM IONIC LIQUIDS
Authors: Pechnikova Nadezhda L. , Smirnov Alexander S. , Lyubimtsev Alexey V. , Aleksandriiskiy Victor V. , Ageeva Tatyana A.
Published: July 2024

The acrylamide hydrogels containing the porphyrin fragments have been obtained by radical polymerization in a solution. The synthesis has been carried out in the presence of imidazolium ionic liquids with length of the alkyl substituent in the imidazolium ring from C4 to C8. The influence of the used ionic liquids on the structure and some properties of the resulting porphyrin-containing acrylamide hydrogels has been established. The addition of an ionic liquid with a different length of the alkyl substituent into the reaction system can influence the structural changes that occur with the porphyrin comonomer during copolymerization with acrylamide. The formation of bacteriochlorin-like structures is inhibited in the presence of an ionic liquid in the reaction medium. This effect is most noticeable when using an imidazolium ionic liquid with a C8 alkyl substituent length. Hydrogels synthesized in the presence of ionic liquids have lower specific surface area compared to ones obtained without the use of ionic liquids. The lowest specific surface area values were shown by hydrogels synthesized using 1-octyl-3-methylimidazolium bromide. It was also found that the introduction of ionic liquid into the reaction mixture can contribute to both increase and decrease in the numerical values of the sorption characteristics of the resulting hydrogels, depending on the length of the alkyl substituent in the imidazolium ring and a porphyrin : acrylamide ratio. Hydrogels synthesized using 1-hexyl-3-methylimidazolium bromide and 1-octyl-3-methylimidazolium bromide at an initial porphyrin : acrylamide ratio of 1:20 have the highest degree of swelling. Varying the ratio of the initial monomers and the structure of the imidazolium ionic liquid during the copolymerization process allows to control the physicochemical characteristics of the resulting porphyrin-containing hydrogels, which can be useful for solving various applied problems.
For citation:
Pechnikova N.L., Smirnov A.S., Lyubimtsev A.V., Aleksandriiskiy V.V., Ageeva T.A. Synthesis of polyacrylamide hydrogels with porphyrin fragments in the side chain in the presence of imidazolium ionic liquids. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 6. P. 73-79. DOI: 10.6060/ivkkt.20246706.7053.
COMPLEX TITANIUM-CONTAINING REAGENTS IN WASTEWATER TREATMENT PROCESSES OF THE FISHING INDUSTRY
Authors: Kuzin Evgeniy N.
Published: July 2024

The issues of removing nutrients from wastewater from various industries have recently received more and more attention. Traditional coagulants based on aluminum and iron salts can effectively remove phosphate ions from water, but these reagents are not effective against ammonium ions. As part of the work done, the possibility of using complex titanium-containing coagulants in the processes of dephosphatization of wastewater from the fish processing industry was considered. It has been proven that the use of magnesium titanium reagents makes it possible to carry out the coprecipitation of ammonium and phosphate ions in the form of the complex compound of magnesium ammonium phosphate (struvite) with high efficiency. To implement the purification process, a 10–20% stoichiometric excess of magnesium compounds from the calculated value is required, while the efficiency of precipitation of ammonium compounds exceeds 50%, and phosphate anion 95%. The optimal pH range for the process of coprecipitation of ammonium and phosphate ions in the form of a complex compound is 10.0 – 10.5. The results of studies conducted on real water from a fish processing plant demonstrated the increased efficiency of complex titanium-containing reagents compared to traditional coagulants based on aluminum, iron and magnesium salts. The possibility of using magnesium-containing waste from the production of refractory materials has been established both as a precursor for the production of complex coagulants and as an individual reagent. It has been proven that the use of complex titanium-containing reagents makes it possible to significantly intensify the processes of sedimentation (15%) and filtration (20%) of coagulation sludge. The use of complex reagents will significantly increase the level of environmental safety of production and reduce the anthropogenic load on the hydrosphere.
For citation:
Kuzin E.N. Complex titanium-containing reagents in wastewater treatment processes of the fishing industry. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 127-135. DOI: 10.6060/ivkkt.20246707.6997.
SYNTHESIS AND STUDY OF THE OPTICAL PROPERTIES OF THE COLLOIDAL FORM OF IRON WITH RIBOFLAVIN AND L-LYSINE
Authors: Blinov Andrey V. , Golik Alexey B. , Rekhman Zafar A. , Gvozdenko Alexey A. , Kolodkin Maxim A. , Bakholdina Tamara N.
Published: July 2024

This paper presents the results of the development and study of a colloidal complex of the essential microelement iron with vitamin B2 riboflavin and the essential amino acid L-lysine. As a result, a method for obtaining a colloidal vitamin-microelement-amino acid complex has been developed, which is carried out in 2 stages. As a result of computer quantum chemical modeling, the most optimal configuration for the interaction of the components of the colloidal complex was determined. Namely, it was found that the connection of riboflavin with the iron ion occurs through oxygen at C4 and nitrogen N3, and lysine binds to the iron ion through the carboxo and amino group in α- position. The optical characteristics of the resulting compound were studied. From an analysis of the absorption spectrum of a 0.001% aqueous solution of an iron complex with riboflavin and L-lysine, the presence of 4 maxima in the spectrum with positions at 222, 265, 374 and 436 nm was established. In the spectrum, the absorption maximum at a wavelength of 436 nm corresponds to the auxochromic amino group; its hypsochromic shift by 20 nm relative to the absorption spectrum of pure riboflavin confirms the formed bond of the amino group with the iron ion in the complex molecule. The fluorescence maximum is located at a wavelength of 522 nm, which corresponds to intense green-yellow fluorescence in both a solution of pure riboflavin and a colloidal iron complex with riboflavin and L-lysine. Analysis of the histogram of the size distribution of micelles of the complex showed the presence of one phase with a size of about 96 nm, which allows us to define the resulting iron complex with riboflavin and the amino acid L-lysine as a colloidal system.
For citation:
Blinov A.V., Golik A.B., Rekhman Z.A., Gvozdenko A.A., Kolodkin M.A., Bakholdina T.N. Synthesis and study of the optical properties of the colloidal form of iron with riboflavin and L-lysine. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 96-102. DOI: 10.6060/ivkkt.20246707.6999.
STUDYING THE THERMOCHEMICAL CHARACTERISTICS OF SINTERING WITH ALKALI CONCENTRATE FROM WASTE COPPER TAILINGS
Authors: Karimova Lyutsiya M. , Kairalapov Yerlan T. , Makasheva Guldana K. , Kharchenko Yelena M.
Published: July 2024

A long period of deposit development leads to a reduction in the volume of balance reserves of ores, while the volume of accumulation of waste (tailings) from mining and processing production increases. In connection with this, an urgent problem is the processing of waste tailings, which can serve as an additional source of commercial products of non-ferrous metals. The set objectives can be achieved by implementing comprehensive extraction of valuable components, reducing fuel, and energy costs at the stage of low-temperature sintering to produce white soot (grade BS-100). In order to determine the amount of heat of chemical reactions during sintering of rough copper concentrate with sodium hydroxide, thermochemical calculations were carried out. For the research, we used rough copper concentrate with a copper content of 4.40% and silver of 77.03 g/t. An equation has been obtained for calculating the heat of chemical reactions of rough concentrate sintering. According to this equation, the greatest contribution to the heat release is provided by the iron content (60%), three times less and equally (19%) - copper and silicon and about 0.2% is absorbed by aluminum. The thermal effect of sintering will be -920.45 kW·h/t of concentrate. From the heat balance of sintering it follows that with an alkali consumption of up to 200% of the mass of the concentrate. The heat of chemical reactions will be sufficient for the autogeneity of the process. Research has been carried out on sintering the concentrate with alkali in the temperature range of 250-500 °C and obtaining white soot from a productive leaching solution with the extraction of 60% silicon. White soot (mSiO2·nH2O) was isolated by two-stage carbonization of a silicate solution with carbon dioxide in a recirculation system with further washing of the precipitate with a solution of sulfuric acid.
For citation:
Karimova L.M., Kairalapov Ye.T., Makascheva G.K., Kharchenko Ye.M. Studying the thermochemical characteristics of sintering with alkali concentrate from waste copper tailings. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 72-79. DOI: 10.6060/ivkkt.20246707.7004.
INTERACTION OF L-CARNOSINE WITH NICOTINIC AND ISONICOTINIC ACIDS IN AQUEOUS SOLUTIONS AT 298.15 K
Authors: Tyunina Elena Yu. , Mezhevoi Igor N. , Barannikov Vladimir P.
Published: July 2024

Understanding the mechanism of interaction of drugs with proteins has drawn attention of numerous researchers. The thermodynamic investigations of liquid-phase systems containing peptide and drug make it possible to determine the nature and driving forces of the interaction between them. In this work, we present results of interaction study of peptide L-carnosine (Car), as model of polypeptide chains in protein, with isonicotinic and nicotinic acids, as the drug models, in aqueous solution using calorimetric method. Calorimetric measurements of the enthalpy of L-carnosine dissolution in water and aqueous solutions with two isomers of pyridine carboxylic acid additives were performed on an ampoule-type isoperibolic dissolution calorimeter at 298.15 K. The error of measuring single heat effects was below 0.2%. The relative combined uncertainty in the measurements of the enthalpies of dissolution was not more than 0.7%. Based on the obtained experimental data and the using the HEAT computer program, the thermodynamic parameters (lgKc, ΔcG, ΔcH, ΔcS) of the complex formation between the reagents were calculated. A comparison of the affinity of peptide to interaction with nicotinic acid and isonicotinic acid was carried out. It is shown that the interaction of L-carnosine with isonicotinic acid leads to the formation of a more stable complex than with nicotinic acid. This fact may be mainly explained by the changing of ionic state of the reagents in solution and the predominance of the zwitterionic forms of isonicotinic acid in compared with nicotinic acid. The data obtained reveal the presence of molecular complexes between Car and isomers of pyridine carboxylic acid with 1:2 stoichiometry in aqueous solutions. The complexes of Car with the isonicotinic acid are mainly enthalpically stabilized, while those of Car with nicotinic acid are stabilized by both enthalpic and entropic contributions to the free Gibbs energy. The main interactions in complexes stabilization are believed to be electrostatic forces and hydrogen bonds formation between peptide and pyridine monocarboxylic acids.
For citation:
Tyunina E.Yu., Mezhevoi I.N., Barannikov V.P. Interaction of L-carnosine with nicotinic and isonicotinic acids in aqueous solutions at 298.15 K. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 48-54. DOI: 10.6060/ivkkt.20246707.7010.
CORROSION INHIBITION BEHAVIOUR OF CUSTARD APPLE LEAVES AND ACACIA CONCINNA EXTRACT ON MILD STEEL IN ACIDIC MEDIA: ADSORPTION AND THERMODYNAMIC STUDY
Authors: Shinde Jitendra Kisan , Puri Ravindra Gulab , Meshram Pawan Devidas , Sirsam Rajkumar Shankarrao
Published: July 2024

Custard apple leaves extract (CALE) was tested to evaluate corrosion inhibition efficiency for mild steel under acidic medium. The test metal substrate was collected over a period of 24 hr of contacting with acid to determine the corrosion inhibition efficiency (CIE) and corrosion rate (CR) using the Gravimetric analysis. The findings of the study were applied to examine the adsorption behavior and thermodynamic characteristics for CALE as a potential corrosion inhibitor in acidic environment. Mild steel exhibited the highest corrosion rate in the absence of a corrosion inhibitor in a 0.5 M sulphuric acid solution. However, the rate of corrosion was observed to decrease gradually with increase in CALE concentration (0.4–2.0 g/l). The similar trend was noted at the experimental temperature range of 298-328 K. Adsorption behavior was investigated using the Langmuir, Temkin, Freundlich, and Flory Huggins adsorption isotherm models. The Temkin adsorption isotherm model provides the best fit to the experimental data. Besides, the negative values of Gibb’s free energy of adsorption (ΔGad) reveal strong evidence for the spontaneous nature of CALE adsorption on mild steel surface. The increase in activation energy (Ea) from 35.05 kJ/mol in the blank test solution to 68.03 kJ/mol at 2.0 g/l concentration of CALE indicates the formation of a protective film of inhibitor molecules on the metal surface. Adsorption enthalpy values (∆H=31.28-73.79 kJ/mol) over the concentration range (0-2.0g/l of CALE) implies physical adsorption, whereas negative entropy values (ΔS) suggests free movement of inhibitor molecules in the bulk solution. Additionally, a synergistic effect was demonstrated in lowering the corrosion rate by combining Acacia concinna extract (ACE, 0.1-0.3 g/l) with CALE, thereby enhancing the overall corrosion inhibition efficiency.
For citation:
Jitendra Kisan Shinde, Ravindra Gulab Puri, Pawan Devidas Meshram, Rajkumar Shankarrao Sirsam Corrosion inhibition behaviour of Custard apple leaves and Acacia concinna extract on mild steel in acidic media: adsorption and thermodynamic study. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 119-126. DOI: 10.6060/ivkkt.20246707.7038.
DESTRUCTION OF VITAMIN B12 DURING INTERACTION WITH ACTIVE OXYGEN SPECIES
Authors: Erina Alina A. , Borodulin Vladimir B. , Dereven’kov Ilia A. , Makarov Sergei V. , Ischenko Anatoliy A.
Published: July 2024

One of the most attractive molecular systems in the world of chemistry and medicine is vitamin B12, which was originally discovered as a factor against deficiency (pernicious) anemia. Deficiency of this essential vitamin leads to a decrease in the number of red blood cells in the blood and a drop in hemoglobin levels. The article provides a brief overview of the processes leading to the destruction of vitamin B12 caused by hypoxia, the action hypochlorous acid, superoxide anion radical, hydrogen peroxide, hydroxyl radical, peroxynitrite. Under conditions of hypoxia, oxygen transport in the electron transport chain may be disrupted, resulting in the reduction of oxygen on ubiquinone to a superoxide radical under the action of electrons that have not reached cytochrome oxidase. Oxidative stress develops, during which oxygen-containing radicals are formed, which can cause irreversible changes in the vitamin and lead to loss of biological activity. Hydrogen peroxide formed as a result of step-by-step protonation of the formed superoxide-anion radicals can act as such oxidants. Hydrogen peroxide, in turn, is capable of reacting with metals of variable oxidation state to form a reactive hydroxyl radical, producing the Fenton reaction. In addition, hypochlorous acid formed by the enzyme myeloperoxidase in the presence of hydrogen peroxide and chloride anion, as well as peroxynitrite, an active oxidant obtained by reacting the superoxide–anion radical with nitrogen (II) oxide, can act as oxidants. The latter is produced in large quantities under hypoxia conditions due to an increase in the activity of endothelial nitric oxide synthetase. The publications devoted to the influence of various oxidants on the stability of vitamin B12 are considered.
For citation:
Erina A.A., Borodulin V.B., Dereven’kov I.A., Makarov S.V., Ischenko A.A. Destruction of vitamin B12 during interaction with active oxygen species. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 6-18. DOI: 10.6060/ivkkt.20246707.7043.
COMPOSTAGEM DE RESÍDUOS DA PRODUÇÃO AGRÍCOLA DE CAFÉ E MILHO COMO FORMA DE ESTRATÉGIA DE CONSERVAÇÃO DO SOLO: UM ESTUDO DE CASO NO MUNICÍPIO DE LINHARES, ESPÍRITO SANTO
Authors: Dos Santos Goncalves Ana Karolyne , Anderson Fellipe Santana Silva  , Amanda Soares Zambelli Ferretti
Published: July 2024

A população do Espírito Santo, atualmente em torno de 3,8 milhões, deve alcançar 4,9 milhões até2060. Esse crescimento populacional, aliado ao aumento no consumo, pode levar à degradaçãoirreversível do solo, especialmente em culturas essenciais como café e milho. A produção de cafésolúvel gerou US$108 milhões em 2022, representando 19,4% das exportações brasileiras de cafésolúvel, enquanto a produção de milho pode crescer 33,8% na safra 2022/23. No entanto, essasculturas sofrem com a erosão causada por práticas agrícolas intensivas, tais como a monocultura e ouso excessivo de maquinário pesado. A reutilização dos resíduos agrícolas através da compostagemoferece uma solução sustentável, melhorando as características físicas, químicas e biológicas do solo.O principal objetivo deste estudo é demonstrar como a compostagem pode se constituir de uma técnicafinanceiramente acessível e eficaz na manutenção e melhoria do solo em culturas de café e milho noEspírito Santo, visando mitigar os efeitos da erosão. Para isso, foi realizada uma pesquisa bibliográficasobre compostagem e sua aplicação na nutrição e preservação do solo. Também foram realizadaspesquisas de campo em fazendas de Córrego Farias, Linhares, Espírito Santo, onde foram observadasmelhorias no solo e aumento da produtividade após a compostagem de resíduos agrícolas. Acompostagem de resíduos de café e milho é uma prática eficiente para a reciclagem orgânica e apreservação do solo. A casca de café pode controlar pragas, conservar umidade e fornecer nutrientesessenciais, enquanto os caules secos de milho funcionam como cobertura morta, adicionandonutrientes e protegendo o solo. A compostagem melhora a estrutura do solo, aumenta a retenção deágua e fornece nutrientes, resultando em uma maior produtividade das culturas. Além disso, reduz oscustos com fertilizantes químicos e atrai consumidores conscientes de práticas sustentáveis.
PLANEJAMENTO ORÇAMENTÁRIO E A IMPREVISIBILIDADE DE DOENÇAS RARAS
Authors: Ana Paula Rodrigues dos Santos  , Marques Mikaelly , Gustavo Chalegre Pelisson
Published: July 2024

O presente estudo enfatizará o custeio de doenças raras no âmbito do Sistema Único de Saúde (SUS) e a imprevisibilidade quantitativa de novos portadores, gerando impacto orçamentário aos cofres públicos. O levantamento é meramente em caráter exploratório, abordando o contingenciamento de despesas excedentes. Desse modo, evidência que as inúmeras ações judiciais procedentes impondo ao poder executivo a cobertura de tratamento ocasionará a realocação de verbas, gerando assim a imperiosidade do planejamento orçamentário para esses gastos imprevisíveis. Outrossim, muitos tem-se a saúde como um dos direitos fundamentais absoluto, no entanto, embora sua imprescindibilidade a condição humana, nem um direito fundamental é absoluto, nem mesmo a vida, podendo ocorrer a sua relativização em detrimento dos direitos transindividuais ou da impossibilidade de custeio. Noutra banda, o aumento da produção de medicamentos em âmbito nacional reduziria o alto custo do tratamento de doenças raras, contudo a implementação de novas tecnologias e insumos no país carece de aval da CONITEC (Comissão Nacional de Incorporação de Tecnologias no Sistema Único de Saúde), sofrendo ponderações e consequentemente a morosidade na implementação de novas terapias.
Comparative investigation of genetic diversity in garden pea (Pisum sativum var. hortense L.) for yield and yield attributing characters
Authors: Gautam Keshav K , Moharana DP , Singh Vikas , Syamal MM
Published: July 2024

Pisum sativum var. hortense L., the garden pea or green pea, belongs to the legume family, viz., fabaceae It is acool season vegetable crop cultivated worldwide mainly for its immature seeds and pods for vegetable purpose as well as for various processed products. Being one of the world’s oldest crops, it was domesticated over 9000 years ago and has been produced in association with cereals since that time (McPhee 2003).
Performance of advanced breeding lines of green-long brinjal for resistance to bacterial wilt disease resistance, yield and quality attributes
Authors: Sahana KP , Kattegoudar Jyothi , Lingaiah HB , Sangeetha CG , Prashanth SJ , Padmanabha K , Ugalat Jayashree
Published: July 2024

Brinjal (Solanum melongena L.) is well known as eggplant or aubergine belongs to the family Solanaceae and is one of the major indigenous vegetable crops grown in India. The name eggplant is derived from the shape of the fruit of mostof the varieties, which are white in colour and similar to the shape of chicken eggs. Eggplant is a perennial, warm weather crop however grown commercially as an annual crop.
Genetic variability studies in tomato (Solanum lycopersicum L.) under ecofriendly management
Authors: Chabbi Vijayakumar , Gupta Rakesh Kumar , Kumar Sanjeev , Kumar Manoj
Published: July 2024

Twenty genotypes of tomato were evaluated for yield, quality and other traits under eco-friendly management. Analysis of variance revealed that highly significant differences among genotypes for all the traits. High magnitude of phenotypic coefficients of variation and genotypic coefficients of variation were observed for traits including fruit yield per plant, plant height and number of fruits per plant. High heritability coupled with high genetic advance estimates were observed for number of fruits perplant, plant height and fruit yield per plant. Fruit yield/planthad positive and highly significant correlation with number of fruits/ plant, fruit weight, fruit shape index and number of primary branches/plant indicating these traits are important yield components. Whereas, negative andsignificant association with days to 50% flowering, leaf curl and fruit borer incidence, ascorbic acid content and thickness. Maximum positive and direct effect towards fruit yield/plant was exerted by average fruit weight, number of fruits per plant, leaf curl incidence and plant height. Few genotypes with high yield and other useful traits were identified for future under eco-friendly management.
Combining ability analysis for yield and quality traits in ridge gourd (Luffa acutangula L. Roxb.)
Authors: Chittora Akshay , Kaushik RA , Ameta KD
Published: July 2024

The investigation was carried out to study combining ability in ridge gourd through line × tester analysis in which 11 lines were crossed with 3 testers to get 33 F1 hybrids. These 33 F1s along with 14 parents were evaluated in Randomized Block Design with three replications under four environments consisting of two locations and two seasons during 2016-17. The parents DRG-3, DRG-5, DRG-15 and Konkan Harita were good general combiners for fruit yield, fruit quality and yield attributing traits and therefore, these are proposed for their further utilization in hybrid breeding programme. Hybrids DRG-15 × Konkan Harita and DRG-3 × Konkan Harita exhibited good specific combining ability for yield per plant and yield contributing characters like number of fruits per plant, fruit weight and fruit diameter. These superior combinations can be further promoted to be utilized as hybrids.
Field screening of F3 and F4 generations of tomato for combined resistance to bacterial wilt and tomato leaf curl virus (ToLCV) diseases
Authors: Dheemanth TL , Kumar PG Sadhan , Nazeem PA , Mathew K , Reddy M Amaranatha
Published: July 2024

The study was carried out with the objective of developing tomato genotypes with combined resistance to bacterial wiltand tomato leaf curl virus. Selfed progeny of five F2 segregants having resistance to both these diseases were screened during 2012-2013 to identify the segregants having the combined resistance. Twenty-two F3 segregants were obtained with combined resistance and the selfed progeny of these plants were raised in bacterial wilt sick field during 2013-2014. A total of 35 F4 segregants having combined resistance were identified. The yield of these F4 plants has ranged from 107 -1447 g and average fruit weight variedfrom 30-86 g. The identified lines were promising to develop tomato varieties with combined resistance to bacterial wilt and ToLCV.
Impact of pre-storage seed invigoration in ash gourd [Benincasa hispida (Thunb.) Cogn.]
Authors: S Athmaja , Francies Rose Mary , Bastian Dijee , George Sarah T , K Anita Cherian
Published: July 2024

Ash gourd is widely cultivated as a vegetable crop in Kerala. In the state, prolonging seed longevity is a major concern as the prevailing hot humid conditions accelerates deterioration of seeds leading to rapid loss of viability during storage. Seed deterioration due toageing is indeed inevitable and irreversible phenomenon, the best that can be done is to lower its rate (Coolbear 1995). It is reported that seed priming technology helps in rapid and uniform germination and emergence of seeds and impart a great tolerance to adverse environmental conditions (Heydecker et al. 1973).
Screening tomato genotypes for resistance against collar rot disease caused by Alternaria solani Sorauer
Authors: Yerasu Suresh Reddy , Murugan Loganathan , HC Prasanna , Singh Arpita
Published: July 2024

Alternaria solani is a soil borne pathogen causing heavy losses to tomato (Solanum lycopersicum L) crop worldwide. It causes early blight symptoms on foliage, collar rot symptom at basal stem region of seedlings, stem lesions on stem of adult plants and fruit rot symptoms on fruits. In comparison to early blight, collar rot screening and differentiating genotype into different resistance classes isrelatively easy. To identify collar rot resistant genotypes thirty tomato accessions of the ICAR-Indian Institute of Vegetable Research, Varanasi, gene bank was screened by inoculating the pathogen under screen house conditions. Three genotypes including two tomato wild species LA 2325(S. neorickii) and WIR 3928 (yellow fruited wild species), and an advanced breeding line H-88-78-1 showed immune reaction to collar rot with zero mean disease severity index. The identified lines are being used as a source of resistance to A. solani to develop disease resistant cultivars.
Mulching and different levels of nitrogen and phosphorus improve yield and quality attributes of broccoli (Brassica oleracea var. italica) and physicochemical property of soil
Authors: Verma Veerendra Kumar , Jha Anjani Kumar , Verma Bibhash Chandra , Chaudhuri Priyajit , Nonglait David
Published: July 2024

A field experiment was conducted on broccoli (Brassica oleracea var. italic) hybrid Puspa during rabi season of 2013-14 to 2015-16 under the mid-hills of Meghalaya. The effect of mulching, different levels of nitrogen and phosphorous on the physicochemical properties of soil, yield and quality attributes of broccoli were studied. The treatments were consisting of nine nutrient combinationshaving three doses of N (Urea) and P2O5 (SSP) with and without mulching. The experiment was conducted in factorial randomized block design with three replications. The observations were recorded for growth, yield and quality attributes of plants and physicochemical properties of soil. All the growth, yield and quality attributes except vitamin-C and â-carotene increases with the increase in dosage of N and P fertilization under mulching condition. The results of mulching also have shown significant improvement in soil fertility parameters as well as yield and quality attributing traits. The treatment comprises of mulch (10 t/ha) + FYM (10 t/ha) + N120P80K60 gave higher gross plant weight (0.8 kg), marketable head weight (0.41 kg) and yield (16.6 t/ha) over the other treatments, could be recommended for the growers of the north eastern region for higher yield (18.4%) and profit.