The article is dedicated to the 90th anniversary of Academician Esen Abikenovich Bekturov, a prominent Kazakhstani chemist who has made outstanding world contribution to physical chemistry of polymers. His scientific interests focused on the study of water-soluble and water-swelling polymers, interpolymer and polymer-metal complexes, polymeric catalysts and associates, polymeric hydrogels, molecular complexes of polymers, nanomaterials and nanotechnology are summarized in numerous monographs published in Japan, Germany, Poland, and Kazakhstan. The essay briefly reflects the life path, creativity, scientific and pedagogical activity of Professor Esen Bekturov as well as the most important and prominent publications. His role in transfer of knowledge, training of high qualified specialists, his contribution in Research and Development (R&D) recognized by numerous International and Republican awards, participation at International Conferences and Symposiums is highlighted.
{"title":"The Contribution of Professor Esen Bekturov to Physical Chemistry of Polymers","authors":"S. Kudaibergenov","doi":"10.31489/2022ch3/3-22-0","DOIUrl":"https://doi.org/10.31489/2022ch3/3-22-0","url":null,"abstract":"The article is dedicated to the 90th anniversary of Academician Esen Abikenovich Bekturov, a prominent Kazakhstani chemist who has made outstanding world contribution to physical chemistry of polymers. His scientific interests focused on the study of water-soluble and water-swelling polymers, interpolymer and polymer-metal complexes, polymeric catalysts and associates, polymeric hydrogels, molecular complexes of polymers, nanomaterials and nanotechnology are summarized in numerous monographs published in Japan, Germany, Poland, and Kazakhstan. The essay briefly reflects the life path, creativity, scientific and pedagogical activity of Professor Esen Bekturov as well as the most important and prominent publications. His role in transfer of knowledge, training of high qualified specialists, his contribution in Research and Development (R&D) recognized by numerous International and Republican awards, participation at International Conferences and Symposiums is highlighted.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83832571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.31489/2022ch4/4-22-18
R. Bhole, P.M. Karche, Y. Shinde, P. Kute, S. Gurav, R. Wavhale
The novel corona virus infection had become a global epidemic due to its rapid spread. So, there is an urgent need to treat COVID-19 patients. The aim of this research was to hypothesize and examine vitamin drug con-jugate as targeted moiety. The present scaffold may have potential role to fight against COVID-19 infection due to its antimicrobial, antioxidants and immunomodulatory activities. Here, we've highlighted the term Vit-amin Drug Conjugate as possible therapy approach for SARS-COV-2 infection. As a result, we synthesize, characterized, and evaluated a Hydroxychloroquine — Folic Acid conjugate (HCQ-FA) by esterification mechanism to provide effective treatment against SARS-CoV-2 infection by enhancing therapeutic effect through synergistic mechanism, masking undesired side effects, and improving cellular internalization. By us-ing prodrug, the efficacy and bioavailability of existing antiviral drugs could be improved. The structure of the conjugate was determined by spectroscopic data like IR, NMR, and mass spectra, which indicates that HCQ-FA conjugate formed by esteric conjugation. Molecular docking studies revealed that HCQ-FA conju-gate shows good level of docking as well as binding interaction with main protease moiety. Molecular dy-namic stimulation revealed that this conjugate shows good stability at the binding site of SARS main protease moiety and exhibits inhibitory activity against COVID-19 infection.
{"title":"Design and Synthesis of Vitamin Drug Conjugate for its Probable Potential Against SARS-COV-2 Infections","authors":"R. Bhole, P.M. Karche, Y. Shinde, P. Kute, S. Gurav, R. Wavhale","doi":"10.31489/2022ch4/4-22-18","DOIUrl":"https://doi.org/10.31489/2022ch4/4-22-18","url":null,"abstract":"The novel corona virus infection had become a global epidemic due to its rapid spread. So, there is an urgent need to treat COVID-19 patients. The aim of this research was to hypothesize and examine vitamin drug con-jugate as targeted moiety. The present scaffold may have potential role to fight against COVID-19 infection due to its antimicrobial, antioxidants and immunomodulatory activities. Here, we've highlighted the term Vit-amin Drug Conjugate as possible therapy approach for SARS-COV-2 infection. As a result, we synthesize, characterized, and evaluated a Hydroxychloroquine — Folic Acid conjugate (HCQ-FA) by esterification mechanism to provide effective treatment against SARS-CoV-2 infection by enhancing therapeutic effect through synergistic mechanism, masking undesired side effects, and improving cellular internalization. By us-ing prodrug, the efficacy and bioavailability of existing antiviral drugs could be improved. The structure of the conjugate was determined by spectroscopic data like IR, NMR, and mass spectra, which indicates that HCQ-FA conjugate formed by esteric conjugation. Molecular docking studies revealed that HCQ-FA conju-gate shows good level of docking as well as binding interaction with main protease moiety. Molecular dy-namic stimulation revealed that this conjugate shows good stability at the binding site of SARS main protease moiety and exhibits inhibitory activity against COVID-19 infection.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88034899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. M. Turdybekov, S. Ivasenko, D. M. Turdybekov, A. Makhmutova, Yury V. Gatilov, S. Adekenov
The article presents the results of a chemical study of Tanacetopsis Pjataevae, which is an endemic plant in Kazakhstan. The amount of extractive substances was obtained by extraction with chloroform from the air-dry crushed above-ground part of the plant collected in the flowering phase. Isolation of compounds was carried out by column chromatography on a column of silica gel brand KSK at a ratio of sum - carrier = 1:20. A colorless crystalline substance of the composition C15H18O4 with m.p. 189-191°C (recrystallized from diethyl ether) was found when the column was eluted with a mixture of petroleum ether-ethyl acetate (87.5:12.5). The structure of the obtained new compound (3-oxo-10β-hydroxy-5,7α(Н),6β(Н)-guai-1,11(13)-diene-6,12-olide) was established on the basis of IR, NMR analysis and mass spectra. The spatial structure was determined by the X-ray diffraction method. It has been established that the 3-oxo-10β-hydroxy-5,7α(Н),6β(Н)-guai-1,11(13)-diene-6,12- olide molecule in the crystal is disordered over two conformational states in the 6 :4 ratio. The stability of these conformers was confirmed by semi-empirical quantum-chemical calculations. It was established that the difference in the heats of formation of two conformers was 6.3 kJ/mol for a free molecule.
{"title":"solation and structure of the new sesquiterpene lactone 3-oxo-10β-hydroxy-5,7α(H),4,6β(H)-guai-1,11(13)-diene-6,12-olide","authors":"K. M. Turdybekov, S. Ivasenko, D. M. Turdybekov, A. Makhmutova, Yury V. Gatilov, S. Adekenov","doi":"10.31489/2022ch2/2-22-8","DOIUrl":"https://doi.org/10.31489/2022ch2/2-22-8","url":null,"abstract":"The article presents the results of a chemical study of Tanacetopsis Pjataevae, which is an endemic plant in Kazakhstan. The amount of extractive substances was obtained by extraction with chloroform from the air-dry crushed above-ground part of the plant collected in the flowering phase. Isolation of compounds was carried out by column chromatography on a column of silica gel brand KSK at a ratio of sum - carrier = 1:20. A colorless crystalline substance of the composition C15H18O4 with m.p. 189-191°C (recrystallized from diethyl ether) was found when the column was eluted with a mixture of petroleum ether-ethyl acetate (87.5:12.5). The structure of the obtained new compound (3-oxo-10β-hydroxy-5,7α(Н),6β(Н)-guai-1,11(13)-diene-6,12-olide) was established on the basis of IR, NMR analysis and mass spectra. The spatial structure was determined by the X-ray diffraction method. It has been established that the 3-oxo-10β-hydroxy-5,7α(Н),6β(Н)-guai-1,11(13)-diene-6,12- olide molecule in the crystal is disordered over two conformational states in the 6 :4 ratio. The stability of these conformers was confirmed by semi-empirical quantum-chemical calculations. It was established that the difference in the heats of formation of two conformers was 6.3 kJ/mol for a free molecule.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88676186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.31489/2022ch2/2-22-23
S. Chitlange, S. Chandani, S.P. S.P. Gandhi, P. Thorat, H. B. Lad
A sensitive High-performance thin-layer chromatography method was developed for simultaneous estimation of berberine, gallic acid and ursolic acid in a polyherbal blend and validated as per ICH guidelines.Polyherbal blend was prepared using widely recommended herbal plants for platelet augmentation activity viz. Carica papaya, Berberis aristata, Ocimum Sanctum and Tinospora Cordifolia. The optimized separation was obtained with TLC aluminum plates pre-coated with silica gel G60 F254 as a stationary phase and a solvent system containing Toluene : Ethyl acetate : Methanol : Formic acid (3:3:0.2:0.1 v/v/v/v). Berberine and gallic acid were found to demonstrate linearity in the range of 1μg/band – 6μg/band and ursolic acid in the range of 20 μg/band – 100 μg/band with the regression coefficient in acceptable limits. The method was also found to be specific and precise one. The accuracy of the developed method at 80 %, 100 % and 120 % levels was found to be within limits and % RSD was found to be less than 2. LOD and LOQ of all three standards were also determined. Blend was also quantified for the amount of berberine, gallic acid and ursolic acid presence and was found to be 37.8 μg, 46.1 μg and 108 μg per mg, respectively.
{"title":"Development and validation of HPTLC method for simultaneous estimation of berberine, gallic acid and ursolic acid in a polyherbal blend","authors":"S. Chitlange, S. Chandani, S.P. S.P. Gandhi, P. Thorat, H. B. Lad","doi":"10.31489/2022ch2/2-22-23","DOIUrl":"https://doi.org/10.31489/2022ch2/2-22-23","url":null,"abstract":"A sensitive High-performance thin-layer chromatography method was developed for simultaneous estimation of berberine, gallic acid and ursolic acid in a polyherbal blend and validated as per ICH guidelines.Polyherbal blend was prepared using widely recommended herbal plants for platelet augmentation activity viz. Carica papaya, Berberis aristata, Ocimum Sanctum and Tinospora Cordifolia. The optimized separation was obtained with TLC aluminum plates pre-coated with silica gel G60 F254 as a stationary phase and a solvent system containing Toluene : Ethyl acetate : Methanol : Formic acid (3:3:0.2:0.1 v/v/v/v). Berberine and gallic acid were found to demonstrate linearity in the range of 1μg/band – 6μg/band and ursolic acid in the range of 20 μg/band – 100 μg/band with the regression coefficient in acceptable limits. The method was also found to be specific and precise one. The accuracy of the developed method at 80 %, 100 % and 120 % levels was found to be within limits and % RSD was found to be less than 2. LOD and LOQ of all three standards were also determined. Blend was also quantified for the amount of berberine, gallic acid and ursolic acid presence and was found to be 37.8 μg, 46.1 μg and 108 μg per mg, respectively.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87299091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Deberdeev, A. Akhmetshina, L. K. Karimova, S. V. Grishin, D. V. Kochemasova
Liquid crystalline polymers, depending on their structure and macromolecular architecture, are found in a number of commercial applications, ranging from state-of-the-art engineering plastics to soft matter artificial muscles and microrobots. Rigid chain liquid crystalline polymers are known as indispensable materials for high technology industries. However, their relatively high costs provoke the search for novel cost-effective mesogenic monomers. In this regard, a series of aromatic oligoesters and oligoesteramides were synthesized via high-temperature polycondensation of aromatic dicarboxylic acids with 4-hydroxybenzoic acid (or 4-aminobenzoic acid) and 1,5-naphthalene diol. The structure of the synthesized compounds was identified using FTIR spectra analysis. According to polarizing microscopy observations, novel oligoester based on 4-hydroxybenzoic acid, 1,5-naptalene diol and terephthalic acid demonstrated liquid crystallinity with nemat-ic texture, whereas other samples occurred in amorphous state in case of oligoester or in crystalline state in case of oligoesteramides. A relatively wide range of mesophase existence from 120 to 290 °C was found for the thermotropic oligoester using differential scanning calorimetry. While aromatic oligoesters at the begin-ning of the degradation processes were highly stable towards heat with comparable values of Т10, which were equal to 372–378 °C, aromatic oligoesteramides started to decompose at the temperatures lower by more than 50 °C than those for oligoesters.
{"title":"Thermal Behavior of Novel Aromatic Oligoesters and Oligoesteramides","authors":"T. Deberdeev, A. Akhmetshina, L. K. Karimova, S. V. Grishin, D. V. Kochemasova","doi":"10.31489/2022ch3/3-22-5","DOIUrl":"https://doi.org/10.31489/2022ch3/3-22-5","url":null,"abstract":"Liquid crystalline polymers, depending on their structure and macromolecular architecture, are found in a number of commercial applications, ranging from state-of-the-art engineering plastics to soft matter artificial muscles and microrobots. Rigid chain liquid crystalline polymers are known as indispensable materials for high technology industries. However, their relatively high costs provoke the search for novel cost-effective mesogenic monomers. In this regard, a series of aromatic oligoesters and oligoesteramides were synthesized via high-temperature polycondensation of aromatic dicarboxylic acids with 4-hydroxybenzoic acid (or 4-aminobenzoic acid) and 1,5-naphthalene diol. The structure of the synthesized compounds was identified using FTIR spectra analysis. According to polarizing microscopy observations, novel oligoester based on 4-hydroxybenzoic acid, 1,5-naptalene diol and terephthalic acid demonstrated liquid crystallinity with nemat-ic texture, whereas other samples occurred in amorphous state in case of oligoester or in crystalline state in case of oligoesteramides. A relatively wide range of mesophase existence from 120 to 290 °C was found for the thermotropic oligoester using differential scanning calorimetry. While aromatic oligoesters at the begin-ning of the degradation processes were highly stable towards heat with comparable values of Т10, which were equal to 372–378 °C, aromatic oligoesteramides started to decompose at the temperatures lower by more than 50 °C than those for oligoesters.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87926591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.31489/2022ch2/2-22-22
G. Burkeyeva, Y. Tazhbayev, D. Muslimova, G.D. Nurseiit, L. Zhaparova
The possibility of using the copolymers on the basis of unsaturated polyesters with acrylic acid (AA) as a main component (polymeric basis) for the creation of novel highly-effective sealants and glues of domestic production was demonstrated. Polyethylene glycol maleate (p-EGM) was synthesized by step-growth polymerization of maleic anhydride with ethylene glycol using the catalyst, which shortened the process duration. A number of solutions of p-EGM with AA were obtained. Physicochemical characteristics of initial solutions were determined. Some rheological properties of the solutions of p-EGM in unsaturated carboxylic acid were studied. Radical polymerization — the process of “cold curing” of the solutions of p-EGM with AA at a room temperature was carried out. The combination of initiating system of cold curing consisting of initiator (benzoyl peroxide) and promoter (dimethylaniline) was selected and their optimal content in the initial monomer mixture was established. The main parameters of curing, namely gelation time and curing time were determined. Identification of the copolymers was performed using IR-spectroscopy. The morphology of the surfaces of cured samples of p-EGM with AA was studied using SEM. There was established the optimal composition requiring further studies as highly-filled compositional polymeric materials for using as sealants and glue basis.
{"title":"“Cold curing” of polyethylene glycol maleate with acrylic acid and some physicochemical properties of their solutions","authors":"G. Burkeyeva, Y. Tazhbayev, D. Muslimova, G.D. Nurseiit, L. Zhaparova","doi":"10.31489/2022ch2/2-22-22","DOIUrl":"https://doi.org/10.31489/2022ch2/2-22-22","url":null,"abstract":"The possibility of using the copolymers on the basis of unsaturated polyesters with acrylic acid (AA) as a main component (polymeric basis) for the creation of novel highly-effective sealants and glues of domestic production was demonstrated. Polyethylene glycol maleate (p-EGM) was synthesized by step-growth polymerization of maleic anhydride with ethylene glycol using the catalyst, which shortened the process duration. A number of solutions of p-EGM with AA were obtained. Physicochemical characteristics of initial solutions were determined. Some rheological properties of the solutions of p-EGM in unsaturated carboxylic acid were studied. Radical polymerization — the process of “cold curing” of the solutions of p-EGM with AA at a room temperature was carried out. The combination of initiating system of cold curing consisting of initiator (benzoyl peroxide) and promoter (dimethylaniline) was selected and their optimal content in the initial monomer mixture was established. The main parameters of curing, namely gelation time and curing time were determined. Identification of the copolymers was performed using IR-spectroscopy. The morphology of the surfaces of cured samples of p-EGM with AA was studied using SEM. There was established the optimal composition requiring further studies as highly-filled compositional polymeric materials for using as sealants and glue basis.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88097789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Panshina, A. Bakibaev, A.N. Guslyakov, V. Malkov
Glycoluril (2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione) and its derivatives have a special place in chemis-try of heterocyclic compounds. The macrocyclic derivatives of glycoluril, namely cucurbit[n]urils have re-cently attracted the greatest interest due to their unique properties. Cucurbit[n]urils are usually synthesized by the condensation reaction of glycoluril with paraformaldehyde using strong mineral acids as a catalyst. In this work, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) was used for the first time as a catalyst for “Green chemistry” in the synthesis of cucurbit[6]uril in an aqueous medium. The reaction of glycoluril and paraform-aldehyde in a ratio of 1: 2 with two equivalents of 1-hydroxyethylidene-1,1-diphosphonic acid as a catalyst was carried out, in which the hexamer of cucurbituril (n = 6) was obtained in 25 % yield. The clathrate of cu-curbit[6]uril with acetone was obtained by treating the cucurbituril hexamer with acetone. The reaction of glycoluril with paraformaldehyde in the presence of HEDP can be used as a competitive method for the syn-thesis of cucurbit[6]uril. The structures of the obtained compounds were proven by NMR and IR spectrosco-py methods. The phase composition of isolated crystals of cucurbit[6]uril hydrate was analyzed by the pow-der X-ray diffraction (XRD).
{"title":"Synthesis of Cucurbit[6]uril Using 1-Hydroxyethylidene-1,1-Diphosphonic Acid as a “Green Catalyst”","authors":"S. Panshina, A. Bakibaev, A.N. Guslyakov, V. Malkov","doi":"10.31489/2022ch4/4-22-3","DOIUrl":"https://doi.org/10.31489/2022ch4/4-22-3","url":null,"abstract":"Glycoluril (2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione) and its derivatives have a special place in chemis-try of heterocyclic compounds. The macrocyclic derivatives of glycoluril, namely cucurbit[n]urils have re-cently attracted the greatest interest due to their unique properties. Cucurbit[n]urils are usually synthesized by the condensation reaction of glycoluril with paraformaldehyde using strong mineral acids as a catalyst. In this work, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) was used for the first time as a catalyst for “Green chemistry” in the synthesis of cucurbit[6]uril in an aqueous medium. The reaction of glycoluril and paraform-aldehyde in a ratio of 1: 2 with two equivalents of 1-hydroxyethylidene-1,1-diphosphonic acid as a catalyst was carried out, in which the hexamer of cucurbituril (n = 6) was obtained in 25 % yield. The clathrate of cu-curbit[6]uril with acetone was obtained by treating the cucurbituril hexamer with acetone. The reaction of glycoluril with paraformaldehyde in the presence of HEDP can be used as a competitive method for the syn-thesis of cucurbit[6]uril. The structures of the obtained compounds were proven by NMR and IR spectrosco-py methods. The phase composition of isolated crystals of cucurbit[6]uril hydrate was analyzed by the pow-der X-ray diffraction (XRD).","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"67 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76430277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.31489/2022ch4/4-22-21
V. Shelkovnikov, A. Altyev, M. Fryanova
The electrochemical behavior of methionine at an electrode modified with vitamin B12 and multi-walled car-bon nanotubes has been studied in this work. A possible mechanism of redox processes occurring on the modified electrode is proposed. When the electrode is formed, vitamin B12 is fixed on the surface of a carbon-containing electrode modified with multi-walled carbon nanotubes due to adsorption. In the process of ca-thodic polarization, cobalt(III) in cobalamin is reduced to cobalt(II) to which a partially negatively-charged sulfur atom in the methionine molecule is attached due to electrostatic interactions. During anodic polariza-tion, cobalt(II) in the complex is oxidized up to Co3+, the methyl group from methionine is transferred to cobalamin, and homocysteine passes into the solution, which is proved by Raman spectra. Based on the study of the dependence of current and potential on the sweep speed, it was found that the oxidation process is not reversible, the limiting stage is adsorption, and one proton and one electron participate in the electrochemical stage. The following оptimal conditions for recording an analytical signal were selected: the background elec-trolyte is a tartrate buffer solution with pH = 4.01; the electrolysis potential is 1.6 V; the accumulation time is up to 180 s. The metrological characteristics of the procedure for determining methionine were estimated. The accuracy index did not exceed 29 %, the repeatability and intermediate precision indices did not exceed 14 % and 16 %, respectively. The range of detectable contents was (1–50)×10–7; the detection limit was 5.0×10–8 M. It was shown that a 10-fold excess of ascorbic acid, tryptophan, glycine, cysteine and tyrosine does not have a noticeable distorting effect on the procedure for determining methionine.
{"title":"Study of the Methionine Electrooxidation at an Electrode Modified with Vitamin B12 and Multi-Walled Carbon Nanotubes","authors":"V. Shelkovnikov, A. Altyev, M. Fryanova","doi":"10.31489/2022ch4/4-22-21","DOIUrl":"https://doi.org/10.31489/2022ch4/4-22-21","url":null,"abstract":"The electrochemical behavior of methionine at an electrode modified with vitamin B12 and multi-walled car-bon nanotubes has been studied in this work. A possible mechanism of redox processes occurring on the modified electrode is proposed. When the electrode is formed, vitamin B12 is fixed on the surface of a carbon-containing electrode modified with multi-walled carbon nanotubes due to adsorption. In the process of ca-thodic polarization, cobalt(III) in cobalamin is reduced to cobalt(II) to which a partially negatively-charged sulfur atom in the methionine molecule is attached due to electrostatic interactions. During anodic polariza-tion, cobalt(II) in the complex is oxidized up to Co3+, the methyl group from methionine is transferred to cobalamin, and homocysteine passes into the solution, which is proved by Raman spectra. Based on the study of the dependence of current and potential on the sweep speed, it was found that the oxidation process is not reversible, the limiting stage is adsorption, and one proton and one electron participate in the electrochemical stage. The following оptimal conditions for recording an analytical signal were selected: the background elec-trolyte is a tartrate buffer solution with pH = 4.01; the electrolysis potential is 1.6 V; the accumulation time is up to 180 s. The metrological characteristics of the procedure for determining methionine were estimated. The accuracy index did not exceed 29 %, the repeatability and intermediate precision indices did not exceed 14 % and 16 %, respectively. The range of detectable contents was (1–50)×10–7; the detection limit was 5.0×10–8 M. It was shown that a 10-fold excess of ascorbic acid, tryptophan, glycine, cysteine and tyrosine does not have a noticeable distorting effect on the procedure for determining methionine.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77429703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.31489/2022ch3/3-22-12
P. Kanabekova, A. Martin, A. Kemelbekova, G. Kulsharova
Microfluidic organs-on-chips or microphysiological systems (MPS) are promising tools that can potentially replace animal testing in drug development. MPS are platforms with microchannels seeded with certain organ cells used to emulate in vivo environments in laboratory conditions. Among them, platforms seeded with lung cells called lung-on-chip devices can evaluate the influence of toxic particles, gases, and chemicals on lung tissue in vitro. Lung-on-chip devices allow the mimicry of healthy lung conditions and a wide range of dis-eases (asthma, cancer, autoimmune, infections). This review focuses on the use of electrospun nanofiber membranes as a functional basement membrane which plays a central role in the development of lung-on-a-chip platforms. Here, we briefly introduce microfluidic devices, MPS, and lung-on-chip devices. Existing basement membrane models such as thin-film and gel-based membranes, and their challenges/disadvantages are discussed. Next, the concepts of electrospinning and nanofiber membranes are introduced. Finally, the nanofiber membranes used in lung-on-chip devices are reviewed. Implementation of different polymer mate-rials used to synthesize the nanofiber membranes and different methods for incorporation of the membrane inside the device are discussed. Electrospun nanofiber membranes provide good mechanical properties, allow transmigration of the immune cells, and withstand the physiological strain without affecting the cell viability.
{"title":"Applications of Nanofiber Membranes in Microphysiological Systems","authors":"P. Kanabekova, A. Martin, A. Kemelbekova, G. Kulsharova","doi":"10.31489/2022ch3/3-22-12","DOIUrl":"https://doi.org/10.31489/2022ch3/3-22-12","url":null,"abstract":"Microfluidic organs-on-chips or microphysiological systems (MPS) are promising tools that can potentially replace animal testing in drug development. MPS are platforms with microchannels seeded with certain organ cells used to emulate in vivo environments in laboratory conditions. Among them, platforms seeded with lung cells called lung-on-chip devices can evaluate the influence of toxic particles, gases, and chemicals on lung tissue in vitro. Lung-on-chip devices allow the mimicry of healthy lung conditions and a wide range of dis-eases (asthma, cancer, autoimmune, infections). This review focuses on the use of electrospun nanofiber membranes as a functional basement membrane which plays a central role in the development of lung-on-a-chip platforms. Here, we briefly introduce microfluidic devices, MPS, and lung-on-chip devices. Existing basement membrane models such as thin-film and gel-based membranes, and their challenges/disadvantages are discussed. Next, the concepts of electrospinning and nanofiber membranes are introduced. Finally, the nanofiber membranes used in lung-on-chip devices are reviewed. Implementation of different polymer mate-rials used to synthesize the nanofiber membranes and different methods for incorporation of the membrane inside the device are discussed. Electrospun nanofiber membranes provide good mechanical properties, allow transmigration of the immune cells, and withstand the physiological strain without affecting the cell viability.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77157493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A.A. A.A. Zhubanov, V. Bondaletov, S. Kozhabekov, A. Galymzhan
The present work aims to provide amine-modified polyethylene-acrylic acid (PEAA) copolymers as a pour point depressant (PPD) that will be evaluated for lower pour point of crude oil. For this, PEAA was amidated with butylamine and octadecylamine in the presence of xylene as a solvent at 150 °C for 10 hours to obtain copolymers PEAA/ODA and PEAA/BA. The copolymers were modified by amidation using the carboxyl groups of an ethylene-acrylic acid copolymer as reaction sites in reactions with RNH2. The resulting copoly-mers were purified and analyzed by FTIR spectroscopy. The modified PEAA copolymers were evaluated for their effectiveness as depressants for crude oils by pour point measurements at 50 ppm, 100 ppm and 200 ppm and rheological measurements at 100 ppm. The pour point measurements of the crude oil showed that octadecylamine-modified PEAA copolymer performed better than butylamine-modified and unmodified PEAA copolymer. The effectiveness of the modified copolymers compared to unmodified PEAA can be ex-plained by the polarity of the monoalkylamide groups in the peripheral substituents along the copolymer backbone, which plays a crucial role in preventing the agglomeration of wax crystals in crude oil.
{"title":"Amidation of Polyethylene-Acrylic Acid Copolymer as Pour Point Depressants for Waxy Crude Oils","authors":"A.A. A.A. Zhubanov, V. Bondaletov, S. Kozhabekov, A. Galymzhan","doi":"10.31489/2022ch3/3-22-1","DOIUrl":"https://doi.org/10.31489/2022ch3/3-22-1","url":null,"abstract":"The present work aims to provide amine-modified polyethylene-acrylic acid (PEAA) copolymers as a pour point depressant (PPD) that will be evaluated for lower pour point of crude oil. For this, PEAA was amidated with butylamine and octadecylamine in the presence of xylene as a solvent at 150 °C for 10 hours to obtain copolymers PEAA/ODA and PEAA/BA. The copolymers were modified by amidation using the carboxyl groups of an ethylene-acrylic acid copolymer as reaction sites in reactions with RNH2. The resulting copoly-mers were purified and analyzed by FTIR spectroscopy. The modified PEAA copolymers were evaluated for their effectiveness as depressants for crude oils by pour point measurements at 50 ppm, 100 ppm and 200 ppm and rheological measurements at 100 ppm. The pour point measurements of the crude oil showed that octadecylamine-modified PEAA copolymer performed better than butylamine-modified and unmodified PEAA copolymer. The effectiveness of the modified copolymers compared to unmodified PEAA can be ex-plained by the polarity of the monoalkylamide groups in the peripheral substituents along the copolymer backbone, which plays a crucial role in preventing the agglomeration of wax crystals in crude oil.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85452846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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