Главная
Авторизация
Фамилия
Пароль
 

Базы данных


Труды сотрудников ИБФ СО РАН - результаты поиска

Вид поиска

Область поиска
в найденном
Формат представления найденных документов:
полный информационныйкраткий
Отсортировать найденные документы по:
авторузаглавиюгоду изданиятипу документа
Поисковый запрос: (<.>K=copolymer<.>)
Общее количество найденных документов : 37
Показаны документы с 1 по 20
 1-20    21-37 
1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhila N. O., Sapozhnikova K. Yu., Kiselev E. G., Vasiliev A. D., Nemtsev I. V., Shishatskaya E. I., Volova T. G.
Заглавие : Properties of degradable polyhydroxyalkanoates (Phas) synthesized by a new strain, cupriavidus necator ibp/sfu-1, from various carbon sources
Место публикации : Polym.: MDPI, 2021. - Vol. 13, Is. 18. - Ст.3142. - ISSN 20734360 (ISSN), DOI 10.3390/polym13183142
Аннотация: The bacterial strain isolated from soil was identified as Cupriavidus necator IBP/SFU-1 and investigated as a PHA producer. The strain was found to be able to grow and synthesize PHAs under autotrophic conditions and showed a broad organotrophic potential towards different carbon sources: sugars, glycerol, fatty acids, and plant oils. The highest cell concentrations (7–8 g/L) and PHA contents were produced from oleic acid (78%), fructose, glucose, and palm oil (over 80%). The type of the carbon source influenced the PHA chemical composition and properties: when grown on oleic acid, the strain synthesized the P(3HB-co-3HV) copolymer; on plant oils, the P(3HB-co-3HV-co-3HHx) terpolymer, and on the other substrates, the P(3HB) homopolymer. The type of the carbon source influenced molecular-weight properties of PHAs: P(3HB) synthesized under autotrophic growth conditions, from CO2, had the highest number-average (290 ± 15 kDa) and weight-average (850 ± 25 kDa) molecular weights and the lowest polydispersity (2.9 ± 0.2); polymers synthesized from organic carbon sources showed increased polydispersity and reduced molecular weight. The carbon source was not found to affect the degree of crystallinity and thermal properties of the PHAs. The type of the carbon source determined not only PHA composition and molecular weight but also surface microstructure and porosity of the polymer films. The new strain can be recommended as a promising P(3HB) producer from palm oil, oleic acid, and sugars (fructose and glucose) and as a producer of P(3HB-co-3HV) from oleic acid and P(3HB-co-3HV-co-3HHx) from palm oil. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Scopus
Найти похожие
2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhila, Natalia O., Sapozhnikova, Kristina Yu, Kiselev, Evgeniy G., Vasiliev, Alexander D., Nemtsev, Ivan, V, Shishatskaya, Ekaterina, I, Volova, Tatiana G.
Заглавие : Properties of Degradable Polyhydroxyalkanoates (PHAs) Synthesized by a New Strain, Cupriavidus necator IBP/SFU-1, from Various Carbon Sources
Колич.характеристики :19 с
Коллективы : Russian FederationRussian Federation [075-15-2021-626, 220]; State Assignment of the Ministry of Science and Higher Education of the Russian Federation [FSRZ-2020-0006]
Место публикации : Polymers: MDPI, 2021. - Vol. 13, Is. 18. - Ст.3142. - ISSN 2073-4360(eISSN), DOI 10.3390/polym13183142
Примечания : Cited References:78. - This work was financially supported by Project "Agropreparations of the new generation: a strategy of construction and realization" (Agreement No 075-15-2021-626) in accordance with Resolution No 220 of the Government of the Russian Federation of 9 April 2010, "On measures designed to attract leading scientists to the Russian institutions of higher learning" (strain isolation, polymer synthesis and investigation), and by the State Assignment of the Ministry of Science and Higher Education of the Russian Federation No. FSRZ-2020-0006 (study of film properties).
Предметные рубрики: RALSTONIA-EUTROPHA
POLY(3-HYDROXYBUTYRATE) PRODUCTION
PLANT OIL
ACID
Аннотация: The bacterial strain isolated from soil was identified as Cupriavidus necator IBP/SFU-1 and investigated as a PHA producer. The strain was found to be able to grow and synthesize PHAs under autotrophic conditions and showed a broad organotrophic potential towards different carbon sources: sugars, glycerol, fatty acids, and plant oils. The highest cell concentrations (7-8 g/L) and PHA contents were produced from oleic acid (78%), fructose, glucose, and palm oil (over 80%). The type of the carbon source influenced the PHA chemical composition and properties: when grown on oleic acid, the strain synthesized the P(3HB-co-3HV) copolymer; on plant oils, the P(3HB-co-3HV-co-3HHx) terpolymer, and on the other substrates, the P(3HB) homopolymer. The type of the carbon source influenced molecular-weight properties of PHAs: P(3HB) synthesized under autotrophic growth conditions, from CO2, had the highest number-average (290 +/- 15 kDa) and weight-average (850 +/- 25 kDa) molecular weights and the lowest polydispersity (2.9 +/- 0.2); polymers synthesized from organic carbon sources showed increased polydispersity and reduced molecular weight. The carbon source was not found to affect the degree of crystallinity and thermal properties of the PHAs. The type of the carbon source determined not only PHA composition and molecular weight but also surface microstructure and porosity of the polymer films. The new strain can be recommended as a promising P(3HB) producer from palm oil, oleic acid, and sugars (fructose and glucose) and as a producer of P(3HB-co-3HV) from oleic acid and P(3HB-co-3HV-co-3HHx) from palm oil.
WOS
Найти похожие
3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T. G., Golubev A. I., Nemtsev I. V., Lukyanenko A. V., Dudaev A. E., Shishatskaya E. I.
Заглавие : Laser processing of polymer films fabricated from phas differing in their monomer composition
Место публикации : Polym.: MDPI AG, 2021. - Vol. 13, Is. 10. - Ст.1553. - ISSN 20734360 (ISSN), DOI 10.3390/polym13101553
Аннотация: The study reports results of using a CO2-laser in continuous wave (3 W; 2 m/s) and quasi-pulsed (13.5 W; 1 m/s) modes to treat films prepared by solvent casting technique from four types of polyhydroxyalkanoates (PHAs), namely poly-3-hydroxybutyrate and three copolymers of 3-hydroxybutyrate: with 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate (each second monomer constituting about 30 mol.%). The PHAs differed in their thermal and molecular weight properties and degree of crystallinity. Pristine films differed in porosity, hydrophilicity, and roughness parameters. The two modes of laser treatment altered these parameters and biocompatibility in diverse ways. Films of P(3HB) had water contact angle and surface energy of 92? and 30.8 mN/m, respectively, and average roughness of 144 nm. The water contact angle of copolymer films decreased to 80–56? and surface energy and roughness increased to 41–57 mN/m and 172–290 nm, respectively. Treatment in either mode resulted in different modifications of the films, depending on their composition and irradiation mode. Laser-treated P(3HB) films exhibited a decrease in water contact angle, which was more considerable after the treatment in the quasi-pulsed mode. Roughness parameters were changed by the treatment in both modes. Continuous wave line-by-line irradiation caused formation of sintered grooves on the film surface, which exhibited some change in water contact angle (76–80? ) and reduced roughness parameters (to 40–45 mN/m) for most films. Treatment in the quasi-pulsed raster mode resulted in the formation of pits with no pronounced sintered regions on the film surface, a more considerably decreased water contact angle (to 67–76? ), and increased roughness of most specimens. Colorimetric assay for assessing cell metabolic activity (MTT) in NIH 3T3 mouse fibroblast culture showed that the number of fibroblasts on the films treated in the continuous wave mode was somewhat lower; treatment in quasi-pulsed radiation mode caused an increase in the number of viable cells by a factor of 1.26 to 1.76, depending on PHA composition. This is an important result, offering an opportunity of targeted surface modification of PHA products aimed at preventing or facilitating cell attachment. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Scopus
Найти похожие
4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova, Tatiana G., Golubev, Alexey, I, Nemtsev, Ivan, V, Lukyanenko, Anna, V, Dudaev, Alexey E., Shishatskaya, Ekaterina, I
Заглавие : Laser Processing of Polymer Films Fabricated from PHAs Differing in Their Monomer Composition
Колич.характеристики :24 с
Коллективы : Russian Foundation for Basic Research/Regional State Autonomous Institution "Krasnoyarsk Regional Fund for the Support of Scientific and ScientificTechnical Activities" foundations [19-43-240012]; Ministry of Science and Higher Education of the Russian Federation [FSRZ-2020-0006]
Место публикации : Polymers: MDPI, 2021. - Vol. 13, Is. 10. - Ст.1553. - ISSN 2073-4360(eISSN), DOI 10.3390/polym13101553
Примечания : Cited References:87. - This work was supported by the Russian Foundation for Basic Research/Regional State Autonomous Institution "Krasnoyarsk Regional Fund for the Support of Scientific and ScientificTechnical Activities" foundations under Grant number 19-43-240012 (laser treatment and films properties) and by the State Assignment of the Ministry of Science and Higher Education of the Russian Federation No. FSRZ-2020-0006 (polymer synthesis).
Предметные рубрики: CHEMOMECHANICAL PROPERTIES
PHYSICOCHEMICAL PROPERTIES
SURFACE
Аннотация: The study reports results of using a CO2-laser in continuous wave (3 W; 2 m/s) and quasi-pulsed (13.5 W; 1 m/s) modes to treat films prepared by solvent casting technique from four types of polyhydroxyalkanoates (PHAs), namely poly-3-hydroxybutyrate and three copolymers of 3-hydroxybutyrate: with 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate (each second monomer constituting about 30 mol.%). The PHAs differed in their thermal and molecular weight properties and degree of crystallinity. Pristine films differed in porosity, hydrophilicity, and roughness parameters. The two modes of laser treatment altered these parameters and biocompatibility in diverse ways. Films of P(3HB) had water contact angle and surface energy of 92 degrees and 30.8 mN/m, respectively, and average roughness of 144 nm. The water contact angle of copolymer films decreased to 80-56 degrees and surface energy and roughness increased to 41-57 mN/m and 172-290 nm, respectively. Treatment in either mode resulted in different modifications of the films, depending on their composition and irradiation mode. Laser-treated P(3HB) films exhibited a decrease in water contact angle, which was more considerable after the treatment in the quasi-pulsed mode. Roughness parameters were changed by the treatment in both modes. Continuous wave line-by-line irradiation caused formation of sintered grooves on the film surface, which exhibited some change in water contact angle (76-80 degrees) and reduced roughness parameters (to 40-45 mN/m) for most films. Treatment in the quasi-pulsed raster mode resulted in the formation of pits with no pronounced sintered regions on the film surface, a more considerably decreased water contact angle (to 67-76 degrees), and increased roughness of most specimens. Colorimetric assay for assessing cell metabolic activity (MTT) in NIH 3T3 mouse fibroblast culture showed that the number of fibroblasts on the films treated in the continuous wave mode was somewhat lower; treatment in quasi-pulsed radiation mode caused an increase in the number of viable cells by a factor of 1.26 to 1.76, depending on PHA composition. This is an important result, offering an opportunity of targeted surface modification of PHA products aimed at preventing or facilitating cell attachment.
WOS
Найти похожие
5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kiselev E. G., Vasiliev A. D., Volova T. G.
Заглавие : Synthesis and characterization of multicomponent PHAs
Место публикации : J. Sib. Fed. Univ. - Biol.: Siberian Federal University, 2021. - Vol. 14, Is. 1. - С. 97-113. - ISSN 19971389 (ISSN), DOI 10.17516/1997-1389-0325
Примечания : Cited By :1
Аннотация: Cupriavidus necator B10646 bacterial cells were cultivated in the mode of synthesis of the reserve polyhydroxyalkanoates (PHAs) in the growth medium that contained, in addition to glucose as the main substrate, precursor substrates of the monomers of various monocarboxylic acids - salts of valeric and hexanoic acids, propionate, and ?-butyrolactone. PHA terpolymers and quaterpolymers with different compositions and proportions of monomers were synthesized, and their physicochemical properties were studied. The terpolymers were composed of monomers of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 4-hydroxybutyrate (4HB), or 3-hydroxyhexanoate (3HHx) and had the following compositions: P(3HB/3HB/4HHx) and P(3HB/3HV/4HHx). The quaterpolymers had the following composition: P(3HB/3HV/4HB/3HHx). All copolymer samples, regardless of the composition and proportions of monomers, had lower molecular weights and higher polydispersity values compared to the highly crystalline 3-hydroxybutyrate homopolymer, but retained thermal stability properties, with a difference between the melting point and thermal degradation of at least 100-110 °C. The inclusion of 3HV, 4HB, and 3HHx monomers in the C-chain of 3HB caused changes in the crystalline to amorphous phase ratio and a significant decrease in the degree of crystallinity (Cx), which depended on the type of monomers and their contents in the copolymer. The maximum decrease in Cx (9-17 %) was detected in the P(3HB/3HV/4HB) terpolymer and the P(3HB/3HV/4HB/3HHx) quaterpolymer (30-36 %). The study confirms that there is the possibility of synthesizing polymers with various compositions, including new ones, which differ significantly in their basic properties. © Siberian Federal University. All rights reserved.
Scopus
Найти похожие
6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Vijayamma, Raji, Maria, Hanna J., Thomas, Sabu, Shishatskaya, Ekaterina I., Kiselev, Evgeniy G., Nemtsev, Ivan V., Sukhanova, Anna A., Volova, Tatiana G.
Заглавие : A study of the properties and efficacy of microparticles based on P(3HB) and P(3HB/3HV) loaded with herbicides
Колич.характеристики :13 с
Коллективы : Project "Agropreparations of the new generation: a strategy of construction and realization" [074-02-2018-328]; Government of the Russian Federation [220]
Место публикации : J. Appl. Polym. Sci.: WILEY, 2021. - Ст.e51756. - Article in press. - ISSN 0021-8995, DOI 10.1002/app.51756. - ISSN 1097-4628(eISSN)
Примечания : Cited References:57. - This work was supported by Project "Agropreparations of the new generation: a strategy of construction and realization" (Agreement No 074-02-2018-328) in accordance with Resolution No 220 of the Government of the Russian Federation of April 9, 2010, "On measures designed to attract leading scientists to the Russian institutions of higher learning". Instruments of Krasnoyarsk Regional Center of Research Equipment of Federal Research Center Krasnoyarsk Science Center SB RAS were used.
Предметные рубрики: FENOXAPROP-P-ETHYL
CONTROLLED-RELEASE
BIODEGRADABLE
Аннотация: The wide use of pesticides in agriculture has caused uncontrolled distribution of these chemicals in the environment, calling for the development and investigation of new environmentally friendly formulations, which would reduce human impact on nature. In the present study, the metribuzin (MET), tribenuron-methyl (TBM), and fenoxaprop-P-ethyl (FPE) herbicides were encapsulated in microparticles of degradable microbial polymers - polyhydroxyalkanoates (PHAs) - of two types - poly-3-hydroxybutyrate [P(3HB)] and poly(3-hydroxybutyrate-co-3-hydroxyvalerate [P(3HB/3HV)]. The use of P(3HB) resulted in higher yields of microparticles (63% to 79%) and larger sizes of the particles, whose average diameter was 0.60 +/- 0.06-0.75 +/- 0.11 mu m, while the average diameter of copolymer particles varied between 0.43 +/- 0.12 and 0.55 +/- 0.05 mu m. Encapsulation efficiency was rather determined by the type of herbicide and its solubility, varying from 24.7% to 48.2%. In vitro herbicide release from microparticles to water was affected by herbicide solubility and PHA chemical composition. The readily soluble MET showed the highest release rate, and over 30 days, 64% and 78% of the encapsulated amounts were released from P(3HB) and P(3HB/3HV) microparticles, respectively. High herbicidal activity of microparticles loaded with metribuzin and tribenuron-methyl was demonstrated in the laboratory stands of the Elsholtzia ciliata weed plant.
WOS
Найти похожие
7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Vijayamma R., Maria H. J., Thomas S., Shishatskaya E. I., Kiselev E. G., Nemtsev I. V., Sukhanova A. A., Volova T. G.
Заглавие : A study of the properties and efficacy of microparticles based on P(3HB) and P(3HB/3HV) loaded with herbicides
Место публикации : J. Appl. Polym. Sci.: John Wiley and Sons Inc, 2021. - Article in press. - ISSN 00218995 (ISSN), DOI 10.1002/app.51756
Аннотация: The wide use of pesticides in agriculture has caused uncontrolled distribution of these chemicals in the environment, calling for the development and investigation of new environmentally friendly formulations, which would reduce human impact on nature. In the present study, the metribuzin (MET), tribenuron-methyl (TBM), and fenoxaprop-P-ethyl (FPE) herbicides were encapsulated in microparticles of degradable microbial polymers – polyhydroxyalkanoates (PHAs) – of two types – poly-3-hydroxybutyrate [P(3HB)] and poly(3-hydroxybutyrate-co-3-hydroxyvalerate [P(3HB/3HV)]. The use of P(3HB) resulted in higher yields of microparticles (63% to 79%) and larger sizes of the particles, whose average diameter was 0.60 ± 0.06–0.75 ± 0.11 ?m, while the average diameter of copolymer particles varied between 0.43 ± 0.12 and 0.55 ± 0.05 ?m. Encapsulation efficiency was rather determined by the type of herbicide and its solubility, varying from 24.7% to 48.2%. In vitro herbicide release from microparticles to water was affected by herbicide solubility and PHA chemical composition. The readily soluble MET showed the highest release rate, and over 30 days, 64% and 78% of the encapsulated amounts were released from P(3HB) and P(3HB/3HV) microparticles, respectively. High herbicidal activity of microparticles loaded with metribuzin and tribenuron-methyl was demonstrated in the laboratory stands of the Elsholtzia ciliata weed plant. © 2021 Wiley Periodicals LLC.
Scopus
Найти похожие
8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhila N. O., Kalacheva G. S., Fokht V. V., Bubnova S. S., Volova T. G.
Заглавие : Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by cupriavidus necator B-10646 from mixtures of oleic acid and 3-hydroxyvalerate precursors
Место публикации : J. Sib. Fed. Univ. - Biol.: Siberian Federal University, 2020. - Vol. 13, Is. 3. - С. 331-341. - ISSN 19971389 (ISSN), DOI 10.17516/1997-1389-0320
Аннотация: Polyhydroxyalkanoates have attracted much attention as biodegradable alternative to petroleum-based synthetic plastics. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] copolymer is one of the best characterized PHA copolymers because of its high commercial potential. However, commercial use of PHAs has been limited by their high price. One approach to reducing the cost of PHA production is to use inexpensive carbon sources (fatty acids, plant oils, etc.). The aim of this work was to study synthesis of P(3HB-co-3HV) by the Cupriavidus necator B-10646 bacterium grown on oleic acid and different biochemical precursors of 3HV. Bacterial cells were grown for 72 h at 30°C and 200 rpm on an incubator shaker. Salts of propionic or valeric acids were used as precursors of 3HV. The content and the composition of the polymer were determined by gas chromatography of fatty acid methyl esters. Lipids and polymer were extracted from biomass using the method of Folch. The addition of potassium propionate and valerate did not inhibit bacterial growth and polymer synthesis, the cell concentration and polymer content reaching 9.3-9.5 g/L and 80-83%, respectively. The addition of potassium valerate or propionate led to the synthesis of (P(3HB-co-3HV)) copolymer containing 21.2 and 14.3 mol% of 3HV, respectively. The number average molecular weight (Mn) of the polymer synthesized by the bacterium on oleic acid alone was 220 kDa; the polydispersity of the polymer was 3.5. The polymer synthesized in the presence of potassium valerate and propionate was characterized by a lower Mn (156-178 kDa) and a higher polydispersity of the polymer (4.4-4.9). The main fatty acids (FA) of intracellular lipids were oleic (33.26% of the total FA) and palmitic acid (27.48% of the total FA). The addition of potassium propionate or valerate did not cause any significant changes in the composition of the FA of intracellular lipids of the strain studied. This study demonstrates the ability of C. necator B-10646 to synthesize P(3HB-co-3HV) from mixtures of oleic acid and 3HV precursors. The data obtained can be used to develop and implement an economically feasible process of the P(3HB-co-3HV) production. © Siberian Federal University. All rights reserved.
Scopus
Найти похожие
9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shishatskaya E. I., Menzyanova N. G., Shumilova A. A.
Заглавие : The effect of the chemical composition and structure of polymer films made from resorbable polyhydroxyalkanoates on blood cell response
Место публикации : Int. J. Biol. Macromol.: Elsevier B.V., 2019. - Vol. 141. - С. 765-774. - ISSN 01418130 (ISSN) , DOI 10.1016/j.ijbiomac.2019.09.015
Аннотация: Four PHA types were synthesized in the culture of Cupriavidus eutrophus B-10646 under special conditions, poly(3?hydroxybutyrate) [P(3HB)] and of copolymers, which contained 3HB monomers and 4?hydroxybutyrate (4HB), 3?hydroxyvalerate (3HV), or 3?hydroxyhexanoate (3HHx). All copolymers had the Mw of about 550–670 kDa, and the homopolymer P(3HB) had a significantly higher Mw – 920 kDa. P(3HB?co?4HB) and P(3HB?co?3HHx) had the lowest Cx (42 and 49%) while P(3HB?co?3HV) and P(3HB) exhibited higher Cx values (76%). Polymer films were prepared from different PHAs. Electron microscopy showed differences in the surface microstructure of the films. Films prepared from the P(3HB) were more hydrophobic and the arithmetic mean surface roughness of 71–75 nm, than the copolymer films, which were hydrophilic (57–60°) and had considerably higher roughness (158–177 nm). Blood parameters (hemoglobin and hemolysis) and response of the cells (erythrocytes, platelets, and monocytes) were studied in experiments with blood directly contacting the surface of the films of PHAs with different compositions. Cultivation of blood cells on polymer films did not cause any adverse effects on adhesion and morphology of all cell types. Results of studying blood cell response suggested that the films made from low-crystallinity copolymers containing 4?hydroxybutyrate and 3?hydroxyhexanoate were the best for contact with blood. © 2019 Elsevier B.V.
Scopus,
Смотреть статью
Найти похожие
10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T. G., Shumilova A. A., Nikolaeva E. D., Kirichenko A. K., Shishatskaya E. I.
Заглавие : Biotechnological wound dressings based on bacterial cellulose and degradable copolymer P(3HB/4HB)
Место публикации : Int. J. Biol. Macromol.: Elsevier B.V., 2019. - Vol. 131. - С. 230-240. - ISSN 01418130 (ISSN) , DOI 10.1016/j.ijbiomac.2019.03.068
Примечания : Cited By :1
Ключевые слова (''Своб.индексиров.''): bacterial cellulose--composites--polyhydroxyalkanoates--3 hydroxybutyric acid 4 hydroxybutyric acid copolymer--actovegin--bacterial cellulose--cellulose--collagen type 1--copolymer--cytokeratin 10--cytokeratin 14--solcoseryl--unclassified drug--angiogenesis--animal cell--animal experiment--animal model--animal tissue--biochemical analysis--biocompatibility--burn--cell growth--controlled study--cutaneous parameters--differential scanning calorimetry--drug release--elemental analysis--female--fibroblast--histopathology--in vitro study--in vivo study--inflammation--mechanics--nonhuman--rat--review--wound healing--wound planimetry--x ray analysis
Аннотация: Hybrid wound dressings have been constructed using two biomaterials: bacterial cellulose (BC) and copolymer of 3-hydroxybutyric and 4-hydroxybutyric acids [P(3HB/4HB)] – a biodegradable polymer of microbial origin. Some of the experimental membranes were loaded with drugs promoting wound healing and epidermal cells differentiated from multipotent adipose-derived mesenchymal stem cells. A study has been carried out to investigate the structure and physical/mechanical properties of the membranes. The in vitro study showed that the most effective scaffolds for growing fibroblasts were composite BC/P(3HB/4HB) films loaded with actovegin. Two types of the experimental biotechnological wound dressings – BC/P(3HB/4HB)/actovegin and BC/P(3HB/4HB)/fibroblasts – were tested in vivo, on laboratory animals with model third-degree skin burns. Wound planimetry, histological examination, and biochemical and molecular methods of detecting factors of angiogenesis, inflammation, type I collagen, and keratin 10 and 14 were used to monitor wound healing. Experimental wound dressings promoted healing more effectively than VoskoPran – a commercial wound dressing. © 2019
Scopus,
Смотреть статью,
WOS
Найти похожие
11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shishatskaya, Ekaterina I., Menzyanova, Natalia G., Shumilova, Anna A.
Заглавие : The effect of the chemical composition and structure of polymer films made from resorbable polyhydroxyalkanoates on blood cell response
Колич.характеристики :11 с
Коллективы : Russian Science FoundationRussian Science Foundation (RSF) [17-15-01352]
Место публикации : Int. J. Biol. Macromol.: ELSEVIER, 2019. - Vol. 141. - С. 765-+. - ISSN 0141-8130, DOI 10.1016/j.ijbiomac.2019.09.015. - ISSN 1879-0003(eISSN)
Примечания : Cited References:57. - The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The study is supporting by the Russian Science Foundation, Project No 17-15-01352.
Предметные рубрики: 3-HYDROXYBUTYRATE
BIOCOMPATIBILITY
BIOSYNTHESIS
ADHESION
STENTS
Аннотация: Four PHA types were synthesized in the culture of Cupriavidus eutrophus B-10646 under special conditions, poly(3 hydroxybutyrate) [P(3HB)] and of copolymers, which contained 3HB monomers and 4 hydroxybutyrate (4HB), 3 hydroxyvalerate (3HV), or 3 hydroxyhexanoate (3HHx). All copolymers had the M-w of about 550-670 kDa, and the homopolymer P(3HB) had a significantly higher M-w - 920 kDa. P(3HB co 4HB) and P(3HB co 3HHx) had the lowest C-x (42 and 49%) while P(3HB co 3HV) and P(3HB) exhibited higher C-x values (76%). Polymer films were prepared from different PHAs. Electron microscopy showed differences in the surface microstructure of the films. Films prepared from the P(3HB) were more hydrophobic and the arithmetic mean surface roughness of 71-75 nm, than the copolymer films, which were hydrophilic (57-60 degrees) and had considerably higher roughness (158-177 nm). Blood parameters (hemoglobin and hemolysis) and response of the cells (erythrocytes, platelets, and monocytes) were studied in experiments with blood directly contacting the surface of the films of PHAs with different compositions. Cultivation of blood cells on polymer films did not cause any adverse effects on adhesion and morphology of all cell types. Results of studying blood cell response suggested that the films made from low-crystallinity copolymers containing 4 hydroxybutyrate and 3 hydroxyhexanoate were the best for contact with blood. (C) 2019 Elsevier B.V. All rights reserved.
WOS
Найти похожие
12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T. G., Vinogradova O. N., Zhila N. O., Kiselev E. G., Peterson I. V., Vasil’ev A. D., Sukovatyi A. G., Shishatskaya E. I.
Заглавие : Physicochemical properties of multicomponent polyhydroxyalkanoates: Novel aspects
Место публикации : Polym. Sci. Ser. A: Maik Nauka-Interperiodica Publishing, 2017. - Vol. 59, Is. 1. - С. 98-106. - ISSN 0965545X (ISSN) , DOI 10.1134/S0965545X17010163
Ключевые слова (''Своб.индексиров.''): glycols--medical problems--melting--molecular mass--monomers--polymers--chemical compositions--degree of crystallinity--degrees of crystallinity--multi-component polyhydroxyalkanoates--physicochemical property--polyhydroxyalkanoates--temperature intervals--thermal degradation temperatures--organic polymers
Аннотация: The physicochemical properties such as the degree of crystallinity and temperature and molecularmass characteristics of a number of polyhydroxyalkanoates of various chemical composition synthesized on a complex carbon substrate by bacteria Cupriavidus eutrophus В10646 have been investigated. Two-, three-, and four-component copolymer samples have different sets and ratios of monomers with various lengths of carbon chains: 3-hydroxybutyrate (3HB), 4-hydroxybutyrate (4HB), 3-hydroxyvalerate (3HV), 3-hydroxyhexanoate (3HH), 3-hydroxy-4-methyl valerate (3H4MV), and diethylene glycol (DEG). It has been shown that weight-average molar mass Мw and polydispersity vary in a wide range with no correlation existing with the composition of copolymer polyhydroxyalkanoates and that thermal stability is preserved in the temperature interval between the melting temperature and the thermal degradation temperature from 100 to 120–140°С. The composition and ratio of monomers most notably affect the degree of crystallinity of polyhydroxyalkanoates. Significant differences between the degrees of crystallinity of three- and four-component polyhydroxyalkanoates have been found for the first time. The degree of crystallinity for copolymers P(3HB/3HV/4HB) is 9–22%, and the degree of crystallinity for copolymers P(3HB/3HV/3HH) and P(3HB/3GV/3H4MV) is 41–63%; this value is close to the degree of crystallinity for diblock copolymers P(3HB)/DEG, which is 56–69%. For the four-component copolymers P(3HB/3GV/4HB/3HH), the degree of crystallinity is 30–41%. The values of Мw for the copolymers P(3HB/DEG) are inhomogeneous and the polymers contain fractions uneven with respect to molecular mass: a high-molecular-mass polymer (Мw from 2700 to 4900 kDa) and a low-molecular-mass polymer (Мw = 46–167 kDa). For the copolymers P(3HB)/DEG and P(3HB/3HV/3H4MV), two peaks are observed in the region of melting with the gap between these peaks being 4–20°С. All of the types of copolymer samples, regardless of the monomer ratio, show an increase in elongation at break against the background of a decrease in tensile stress and Young’s modulus, with these effects being pronounced to different extents. On the whole, the properties of multicomponent polyhydroxyalkanoates differ appreciably. © 2017, Pleiades Publishing, Ltd.
Scopus,
Смотреть статью,
WOS
Найти похожие
13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shishatskaya E. I., Nikolaeva E. D., Vinogradova O. N., Volova T. G.
Заглавие : Experimental wound dressings of degradable PHA for skin defect repair
Место публикации : J. Mater. Sci. Mater. Med.: Springer New York LLC, 2016. - Vol. 27, Is. 11. - ISSN 09574530 (ISSN) , DOI 10.1007/s10856-016-5776-4
Ключевые слова (''Своб.индексиров.''): biomaterials--cell culture--cells--cytology--enzyme inhibition--fibroblasts--membranes--natural polymers--nonwoven fabrics--polymer films--proteins--stem cells--weaving--electrospun membranes--extracellular matrix protein--fibroblast cells--hydroxyderivative--mesenchymal stem cell--non-woven membranes--wound dressing materials--wound healing process--tissue
Аннотация: The present study reports construction of wound dressing materials from degradable natural polymers such as hydroxy derivatives of carboxylic acids (PHAs) and 3-hydroxybutyrate/4-hydroxybutyrate [P(3HB/4HB)] as copolymer. The developed polymer films and electrospun membranes were evaluated for its wound healing properties with Grafts—elastic nonwoven membranes carrying fibroblast cells derived from adipose tissue multipotent mesenchymal stem cells. The efficacy of nonwoven membranes of P(3HB/4HB) carrying the culture of allogenic fibroblasts was assessed against model skin defects in Wistar rats. The morphological, histological and molecular studies revealed the presence of fibroblasts on dressing materials which facilitated wound healing, vascularization and regeneration. Further it was also observed that cells secreted extracellular matrix proteins which formed a layer on the surface of membranes and promoted the migration of epidermal cells from the neighboring tissues surrounding the wound. The wounds under the P(3HB/4HB) membrane carrying cells healed 1.4 times faster than the wounds under the cell-free membrane and 3.5 times faster than the wounds healing under the eschar (control).The complete wound healing process was achieved at Day 14. Thus the study highlights the importance of nonwoven membranes developed from degradable P(3HB/4HB) polymers in reducing inflammation, enhancing angiogenic properties of skin and facilitating better wound healing process. © 2016, Springer Science+Business Media New York.
Scopus,
Смотреть статью,
WOS
Найти похожие
14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T., Kiselev E., Vinogradova O., Nikolaeva E., Chistyakov A., Sukovatiy A., Shishatskaya E.
Заглавие : A glucose-utilizing strain, cupriavidus euthrophus B-10646: Growth kinetics, characterization and synthesis of multicomponent PHAs
Место публикации : PLoS ONE. - 2014. - Vol. 9, Is. 2. - ISSN 19326203 (ISSN) , DOI 10.1371/journal.pone.0087551
Ключевые слова (''Своб.индексиров.''): 3 hydroxybutyrate 3 hydroxyhexanoate 3 hydroxyvalerate copolymer--3 hydroxybutyrate 4 hydroxybutyrate 3 hydroxyvalerate copolymer--copolymer--gamma butyrolactone--glucose--hexanoic acid--poly(3 hydroxybutyric acid)--polyhydroxyalkanoic acid--polystyrene--propionic acid--unclassified drug--valeric acid--animal cell--article--bacterial growth--bacterium culture--cell adhesion--cell proliferation--crystal structure--culture optimization--cupriavidus--cupriavidus euthrophus--decomposition--elasticity--film--glucose utilization--kinetics--mechanics--melting point--mouse--nonhuman--nucleotide sequence--physical chemistry--polymerization--strength--synthesis
Аннотация: This study investigates kinetic and production parameters of a glucose-utilizing bacterial strain, C. eutrophus B-10646, and its ability to synthesize PHA terpolymers. Optimization of a number of parameters of bacterial culture (cell concentration in the inoculum, physiological activity of the inoculum, determined by the initial intracellular polymer content, and glucose concentration in the culture medium during cultivation) provided cell concentrations and PHA yields reaching 110 g/L and 80%, respectively, under two-stage batch culture conditions. Addition of precursor substrates (valerate, hexanoate, propionate, ?-butyrolactone) to the culture medium enabled synthesis of PHA terpolymers, P(3HB/3HV/4HB) and P(3HB/ 3HV/3HHx), with different composition and different molar fractions of 3HB, 3HV, 4HB, and 3HHx. Different types of PHA terpolymers synthesized by C. eutrophus B-10646 were used to prepare films, whose physicochemical and physical-mechanical properties were investigated. The properties of PHA terpolymers were significantly different from those of the P3HB homopolymer: they had much lower degrees of crystallinity and lower melting points and thermal decomposition temperatures, with the difference between these temperatures remaining practically unchanged. Films prepared from all PHA terpolymers had higher mechanical strength and elasticity than P3HB films. In spite of dissimilar surface structures, all films prepared from PHA terpolymers facilitated attachment and proliferation of mouse fibroblast NIH 3T3 cells more effectively than polystyrene and the highly crystalline P3HB. Copyright: © 2014 Volova et al.
Scopus
Найти похожие
15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Boyandin A.N., Prudnikova S.V., Karpov V.A., Ivonin V.N., Do N.L., Nguyen T.H., Le TMH, Filichev N.L., Levin A.L., Filipenko M.L., Volova T.G., Gitelson I.I.
Заглавие : Microbial degradation of polyhydroxyalkanoates in tropical soils
Место публикации : Int. Biodeterior. Biodegrad.: ELSEVIER SCI LTD, 2013. - Vol. 83. - С. 77-84. - 8. - ISSN 0964-8305, DOI 10.1016/j.ibiod.2013.04.014
Примечания : Cited References: 74. - This study was financially supported by Project "Biotechnologies of novel biomaterials" (Agreement No. 11.G34.31.0013) in accordance with Resolution No. 220 of the Government of the Russian Federation of April 9, 2010, "On measures designed to attract leading scientists to the Russian institutions of higher learning".
Предметные рубрики: POLY-BETA-HYDROXYBUTYRATE
CHAIN-LENGTH POLYHYDROXYALKANOATES
POLY(3-HYDROXYBUTYRATE) DEPOLYMERASE
COASTAL WATERS
PHA FILMS
BIODEGRADATION
BACTERIA
IDENTIFICATION
POLYESTERS
POLY(3-HYDROXYBUTYRATE-CO-3-HYDROXYVALERATE)
Ключевые слова (''Своб.индексиров.''): polyhydroxyalkanoates (phas)--biopolymers--biopolymer properties--soil biodegradation--pha degrading microorganisms
Аннотация: The integrated study addressing biodegradation of microbial linear polyesters of hydroxyalkanoic acids (polyhydroxyalkanoates, PHAs) in tropical conditions by microbial communities of Vietnamese soils was performed in locations close to Hanoi and Nha Trang, which differed in their weather conditions and microbial communities. It shows that PHA degradation in tropical soils is influenced by polymer chemical composition, specimen shape, and microbial characteristics. The homopolymer of 3-hydroxybutyric acid is degraded at higher rates than the copolymer of 3-hydroxybutyric and 3-hydroxyvaleric acids. The average rates of mass loss were 0.04-0.33% per day for films and 0.02-0.18% for compact pellets. PHA degradation was accompanied by a decrease in the polymer molecular mass and, usually, an increase in the degree of crystallinity, suggesting preferential degradation of the amorphous phase. Under the study conditions, representatives of the bacterial genera Burkholderia, Bacillus, Cupriavidus, Mycobacterium, and Nocardiopsis and such micromycetes as Acremonium, Gongronella, Paecilomyces, and Penicillium, Trichoderma have been identified as major PHA degraders. (C) 2013 Elsevier Ltd. All rights reserved.
Найти похожие
16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Boyandin A.N., Prudnikova S.V., Karpov V.A., Ivonin V.N., D? N.L., Nguy?n T.H., Le T.M.H., Filichev N.L., Levin A.L., Filipenko M.L., Volova T.G., Gitelson I.I.
Заглавие : Microbial degradation of polyhydroxyalkanoates in tropical soils
Место публикации : International Biodeterioration and Biodegradation. - 2013. - Vol. 83. - С. 77-84. - ISSN 09648305 (ISSN) , DOI 10.1016/j.ibiod.2013.04.014
Ключевые слова (''Своб.индексиров.''): biopolymer properties--biopolymers--pha degrading microorganisms--polyhydroxyalkanoates (phas)--soil biodegradation--3-hydroxybutyric acid--degree of crystallinity--hydroxyalkanoic acids--microbial characteristics--microbial degradation--polyhydroxyalkanoates--polymer molecular mass--soil biodegradations--bacteriology--biomolecules--biopolymers--microorganisms--soils--tropics--biodegradation--biodegradation--chemical composition--microbial activity--microbial community--molecular analysis--organic compound--polymer--soil degradation--soil microorganism--tropical soil
Аннотация: The integrated study addressing biodegradation of microbial linear polyesters of hydroxyalkanoic acids (polyhydroxyalkanoates, PHAs) in tropical conditions by microbial communities of Vietnamese soils was performed in locations close to Hanoi and Nha Trang, which differed in their weather conditions and microbial communities. It shows that PHA degradation in tropical soils is influenced by polymer chemical composition, specimen shape, and microbial characteristics. The homopolymer of 3-hydroxybutyric acid is degraded at higher rates than the copolymer of 3-hydroxybutyric and 3-hydroxyvaleric acids. The average rates of mass loss were 0.04-0.33% per day for films and 0.02-0.18% for compact pellets. PHA degradation was accompanied by a decrease in the polymer molecular mass and, usually, an increase in the degree of crystallinity, suggesting preferential degradation of the amorphous phase. Under the study conditions, representatives of the bacterial genera Burkholderia, Bacillus, Cupriavidus, Mycobacterium, and Nocardiopsis and such micromycetes as Acremonium, Gongronella, Paecilomyces, and Penicillium, Trichoderma have been identified as major PHA degraders. В© 2013 Elsevier Ltd.
Scopus
Найти похожие
17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T.G., Zhila N.O., Shishatskaya E.I., Mironov P.V., Vasil'Ev A.D., Sukovatyi A.G., Sinskey A.J.
Заглавие : The physicochemical properties of polyhydroxyalkanoates with different chemical structures
Место публикации : Polymer Science - Series A. - 2013. - Vol. 55, Is. 7. - С. 427-437. - ISSN 0965545X (ISSN) , DOI 10.1134/S0965545X13070080
Ключевые слова (''Своб.индексиров.''): amorphous and crystalline phasis--degrees of crystallinity--physicochemical property--poly(3-hydroxybutirate)--polyhydroxyalkanoate copolymer--temperature characteristic--thermal degradation temperatures--thermoplastic materials--copolymers--monomers--thermoplastic elastomers--structure (composition)
Аннотация: A set of polyhydroxyalkanoates are synthesized, and a comparative study of their physicochemical properties is performed. The molecular masses and polydispersities of polyhydroxyalkanoates are found to be independent of their chemical structures. It is shown that the temperature characteristics and degrees of crystallinity of polyhydroxyalkanoates are affected by the chemical compositions of the monomers and their quantitative contents in the polymers. The incorporation of 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate units into the chain of poly(3-hydroxybutyrate) decreases its melting point and thermal degradation temperature relative to these parameters of a homogeneous poly(3-hydroxybutyrate) sample (175 В± 5 C and 275 В± 5 C, respectively). The higher the content of the second monomer units in the poly(3-hydroxybutirate) chain, the greater the changes. The degrees of crystallinity of polyhydroxyalkanoate copolymers are generally lower than that of poly(3-hydroxybutyrate) (75 В± 5%). The effect on the ratio of the amorphous and crystalline phases of the copolymer samples becomes more pronounced in the series 3-hydroxy-valerate-3-hydroxyhexanoate-4- hydroxybutyrate. The prepared samples exhibit different properties ranging from rigid thermoplastic materials to engineering elastomers. В© 2013 Pleiades Publishing, Ltd.
Scopus
Найти похожие
18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shishatskaya E.I., Nikolaeva E.D., Shumilova A.A., Shabanov A.V., Volova T.G.
Заглавие : Cultivation of multipotent mesenchymal bone marrow cells on matrixes made of resorbable bioplastotan
Место публикации : Cellular Transplantation and Tissue Engineering. - 2013. - Vol. 8, Is. 1. - С. 57-65. - ISSN 1815445X (ISSN)
Ключевые слова (''Своб.индексиров.''): alkaline phosphatase--differentiation--extracellular calcium precipitates--multipotent mesenchymal stromal cells--osteopontin--resorbable bioplastotan
Аннотация: Series of cell carriers made of resorbable polyester Bioplastotan, which is a copolymer of 3- And 4-hydroxybutyric acid, are characterized in this work. With use of various technologies membranes, 3D scaffolds, and nanomatrixes formed by ultrafine fibers produced with electrostatic spinning were constructed. All types of scaffolds provide adhesion of multipotent mesenchymal stromal cells and are suitable for the cultivation and differentiation of cells in the osteoblastes, that confirmed by detection of extracellular calcium precipitates, alkaline phosphatase activity and osteopontin production in cell culture. В© Human stem cells institute, 2013.
Scopus
Найти похожие
19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Goreva A.V., Shishatskaya E.I., Volova T.G., Sinskey A.J.
Заглавие : Characterization of polymeric microparticles based on resorbable polyesters of oxyalkanoic acids as a platform for deposition and delivery of drugs
Место публикации : Polym. Sci. Ser. A: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2012. - Vol. 54, Is. 2. - С. 94-105. - 12. - ISSN 0965-545X, DOI 10.1134/S0965545X12020022
Примечания : Cited References: 33. - This work was supported by the program for Support of Leading Scientific Schools of the Russian Federation (project no. 11.G34.31.0013.2010, Biotechnology of New Biomaterials) and the program of integrated studies of the Presidium of the Siberian Branch, Russian Academy of Sciences (project no. 93).
Предметные рубрики: IN-VITRO RELEASE
POLYHYDROXYBUTYRATE MICROSPHERES
BLENDS
RIFAMPICIN
BIOCOMPATIBILITY
DEGRADATION
FORMULATION
COMPOSITE
CARRIERS
MODEL
Аннотация: The effect of the preparation technique (chemical composition of a polymer, type and method of emulsion mixing, and molecular mass of a drug) on the yield, structure, and size of microparticles obtained from resorbable polyesters of microbiological origin, polyhydroxyalkanoates, is studied. It is found that the concentration of the polymer solution and the method of emulsion mixing are the most significant factors affecting the diameter of microparticles based on polyhydroxyalkanoates; the surface structure of particles depends to a higher extent on the chemical composition of the polymer. The family of microparticles from 100-200 nm to 50-70 mu m in diameter is synthesized. It is shown that the rate of drug release from microparticles in vitro into the medium is higher in the case of 3-hydroxybutyrate copolymers with 3-hydroxyvalerate than in the case of the homopolymer of 3-hydroxybutyrate. This parameter increases with the content of 3-hydroxyvalerate units in the copolymer and the porosity and mass fraction of the drug in particles with a decrease in their sizes. For in vitro systems containing a phosphate buffer, variation in the preparation parameters makes it possible to obtain microparticles with various characteristics suitable for deposition of drugs. For microparticles obtained from polyhydroxyalkanoates and having different diameters, the mathematical description of the kinetics of drug release from the polymer matrix is provided.
Найти похожие
20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shishatskaya E.I., Nikolaeva E.D., Goreva A.V., Brigham C.J., Volova T.G., Sinskey A.J.
Заглавие : An in vivo study of pha matrices of different chemical composition: Tissue reaction and biodegradation
Место публикации : Cellular Transplantation and Tissue Engineering. - 2012. - Vol. 7, Is. 1. - С. 73-80. - ISSN 1815445X (ISSN)
Ключевые слова (''Своб.индексиров.''): degradable polymer matrices--degradation--phas--polyhydroxyalkanoates--subcutaneous implantation--tissue reaction
Аннотация: The study addresses consequences of subcutaneous implantation of film matrices prepared from different PHAs to laboratory animals. No negative effects of subcutaneous implantation of PHA matrices on physiological and biochemical characteristics of the animals were determined. Independently of the matrices composition and duration of the contact with the internal environment of the organism we did not observe any deviations in the behavior of animals, their growth and development, as well as blood functions. Response of the tissues to PHA matrices was comparable with the response to polylactide, but substantially less expressed at the earlier time periods after implantation. Tissues response to implantation of PHA of all types is characterized by short-term (up to 2 weeks) post-traumatic inflammation with formation of fibrous capsules by 30th-60th days with the thickness less than 100 microns, which get thinner down to 40-60 microns by 180th day as the result of involution. No differences in response of tissues and the whole organism were observed for the matrices produced from the homopolymer of 3-hydroxybutyric acid (P3HB), copolymers of 3-hydroxybutyric and 4-hydroxybutyric acids (P3HB/4HB), 3-hydroxybutyric acid and 3-hydroxyvalerianic acids (P3HB/3HV), 3-hydroxybutyric and 3-hydroxyhexanoate acids (P3HB/3HH). Macrophages and foreign-body giant cells actively participate in the response of the tissues to PHAs. In the studied conditions matrices from the copolymers containing 3-hydroxyhexanoate and 4 hydroxybutyrate were determined as more actively degraded PHA. The next less degraded matrices were matrices from the copolymer of P3HB/3HV and the most resistant were P3HB matrices. The slower degradation of PHA matrices was accompanied by delayed development of giantcells response. The studied PHA matrices can be placed in the following range by their degradation: P3HB/3HH - P3HB/4HB - P3HB/HV - P3HB.
Scopus
Найти похожие
 1-20    21-37 
 

Другие библиотеки

© Международная Ассоциация пользователей и разработчиков электронных библиотек и новых информационных технологий
(Ассоциация ЭБНИТ)