<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Publishing DTD v1.3 20210610//EN" "JATS-journalpublishing1-3.dtd">
<article article-type="research-article" dtd-version="1.3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="ru"><front><journal-meta><journal-id journal-id-type="publisher-id">vuzbiochemi</journal-id><journal-title-group><journal-title xml:lang="ru">Известия вузов. Прикладная химия и биотехнология</journal-title><trans-title-group xml:lang="en"><trans-title>Proceedings of Universities. Applied Chemistry and Biotechnology</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">2227-2925</issn><issn pub-type="epub">2500-1558</issn><publisher><publisher-name>ИРНИТУ</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.21285/2227-2925-2023-13-3-333-339</article-id><article-id custom-type="edn" pub-id-type="custom">BUTVBX</article-id><article-id custom-type="elpub" pub-id-type="custom">vuzbiochemi-1067</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>ХИМИЧЕСКИЕ НАУКИ</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="en"><subject>CHEMICAL SCIENCES</subject></subj-group></article-categories><title-group><article-title>Синтез п-аминопиридинметакрилата, его гомополимеризация и свойства</article-title><trans-title-group xml:lang="en"><trans-title>Synthesis, homopolymerization and properties of p-aminopyridine methacrylate</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-6278-1047</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Вахабова</surname><given-names>В. Э.</given-names></name><name name-style="western" xml:lang="en"><surname>Vakhabova</surname><given-names>V. E.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Ваxабова Вусала Энам гызы - научный сотрудник, диссертант.</p><p>Az5004, Сумгаит, ул. С. Вургуна, 124</p></bio><bio xml:lang="en"><p>Vusala E. Vakhabova - Researcher, Dissertation Student.</p><p>124, S. Vurgun St., Az5004, Sumgait</p></bio><email xlink:type="simple">vusalavahabova@gmail.com</email><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-2613-4459</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Гулиев</surname><given-names>К. Г.</given-names></name><name name-style="western" xml:lang="en"><surname>Guliev</surname><given-names>K. G.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Гулиев Казым Гафар оглы - доктор химических наук, доцент, исполнительный директор.</p><p>Az5004, Сумгаит, ул. С. Вургуна, 124</p></bio><bio xml:lang="en"><p>Kazym G. Guliev - Dr. Sci. (Chemistry), Associate Professor, Executive Director.</p><p>124, S. Vurgun St., Az5004, Sumgait</p></bio><email xlink:type="simple">ipoma@science.az</email><xref ref-type="aff" rid="aff-1"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="ru"><institution>Институт полимерных материалов Министерства науки и образования Азербайджанской Республики</institution><country>Азербайджан</country></aff><aff xml:lang="en"><institution>Institute of Polymer Materials of the Ministry of Science and Education of the Republic of Azerbaijan</institution><country>Azerbaijan</country></aff></aff-alternatives><pub-date pub-type="collection"><year>2023</year></pub-date><pub-date pub-type="epub"><day>29</day><month>09</month><year>2023</year></pub-date><volume>13</volume><issue>3</issue><fpage>333</fpage><lpage>339</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Вахабова В.Э., Гулиев К.Г., 2023</copyright-statement><copyright-year>2023</copyright-year><copyright-holder xml:lang="ru">Вахабова В.Э., Гулиев К.Г.</copyright-holder><copyright-holder xml:lang="en">Vakhabova V.E., Guliev K.G.</copyright-holder><license xml:lang="ru" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>Данная работа распространяется под лицензией Creative Commons Attribution 4.0.</license-p></license><license xml:lang="en" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>This work is licensed under a Creative Commons Attribution 4.0 License.</license-p></license></permissions><self-uri xlink:href="https://vuzbiochemi.elpub.ru/jour/article/view/1067">https://vuzbiochemi.elpub.ru/jour/article/view/1067</self-uri><abstract><p>Впервые взаимодействием п-аминопиридина с метакрилоилхлоридом получен п-аминопиридинметакрилат. Методами ИКи ЯМР-спектроскопии доказана его структура. Проведена радикальная гомополимеризация синтезированного п-аминопиридинметакрилата как в массе, так и в растворе бензола (инициатор – динитрил азобисизомасляной кислоты), изучены закономерности процесса. Исследование радикальной полимеризации п-аминопиридинметакрилата показало, что процесс полимеризации в найденных условиях протекает без образования побочных реакций и индукционного периода с максимальным выходом 92%. Было обнаружено, что п-аминопиридинметакрилат при радикальной полимеризации ведет себя как более активный мономер по сравнению с метилметакрилатом. Структура полученного мономера и полимера исследована методами ИКи ЯМР-спектроскопии. На основании данных ИКи ЯМР-спектров установлено, что процесс полимеризации протекает по двойной связи, а заместители остаются незатронутыми в боковой макроцепи. Исследование процесса полимеризации синтезированного мономера в массе показало, что он протекает с автоускорением. Начало автоускорения начинается при ~25%-м превращении мономера в процессе полимеризации, что согласуется с литературными данными. Выявлено, что полимеризация п-аминопиридинметакрилата протекает со скоростью, превосходящей скорость полимеризации метилметакрилата. Вероятно, этот факт связан с влиянием заместителя в мономере на электронное состояние всей молекулы, в результате чего изменяется электронная плотность винильной группы, а растущий радикал стабилизируется с заместителем–М-эффектом. Выявлено, что синтезированный полимер обладает высокими антимикробными свойствами.</p></abstract><trans-abstract xml:lang="en"><p>For the first time, p-aminopyridine methacrylate was synthesized by a reaction between p-aminopyridine and methacryloyl chloride. IR and NMR spectroscopy сonfirmed the obtained compound structure. Radical homopolymerization of synthesized p-aminopyridine methacrylate was carried out either in bulk or in benzene solution (initiator – AIBN). The study of radical polymerization regularities of p-aminopyridine methacrylate discovered no side reactions and induction period of the reported process under the created conditions with a maximum yield of 92%. It was found that p-aminopyridine methacrylate is a more reactive monomer in radical polymerization as compared to methyl methacrylate. The structure of the obtained monomer and polymer was investigated by IR and NMR spectroscopy. Based on these data, the polymerization proceeds by a double bond, with substituents in the side macro chain remaining unreacted. The study of the synthesized monomer polymerization in the bulk indicated the presence of the gel effect. The autoacceleration begins at ~25% monomer conversion during the polymerization process, which agrees with the literature data. It was discovered that the polymerization of p-aminopyridine methacrylate proceeds at a rate higher than that of methyl methacrylate. This observation is likely to be connected with the substituent contribution to the electronic state of the entire monomer molecule. Hence, the electron density of the vinyl group changes and the growing radical becomes stabilized with the substituent –M-effect. The polymer synthesized possesses high antimicrobial properties.</p></trans-abstract><kwd-group xml:lang="ru"><kwd>п-аминопиридин</kwd><kwd>метакрилат</kwd><kwd>гомополимеризация</kwd><kwd>антимикробность</kwd><kwd>метакрилоилхлорид</kwd><kwd>радикальная полимеризация</kwd></kwd-group><kwd-group xml:lang="en"><kwd>p-aminopyridine</kwd><kwd>methacrylate</kwd><kwd>homopolymerization</kwd><kwd>antimicrobial properties</kwd><kwd>methacryloyl chloride</kwd><kwd>radical polymerization</kwd></kwd-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Frommeyer M., Bergander K., Steinbuchel A. Guanidination of soluble lysine-rich cyanophycin yields a homoarginine-containing polyamide // Applied and Environmental Microbiology. 2014. Vol. 80, no. 8. P. 2381–2389. https://doi.org/10.1128/AEM.04013-13.</mixed-citation><mixed-citation xml:lang="en">Frommeyer M., Bergander K., Steinbuchel A. Guanidination of soluble lysine-rich cyanophycin yields a homoarginine-containing polyamide. Applied and Environmental Microbiology. 2014;80(8):2381-2389. https://doi.org/10.1128/AEM.04013-13.</mixed-citation></citation-alternatives></ref><ref id="cit2"><label>2</label><citation-alternatives><mixed-citation xml:lang="ru">Сивов Н.А., Клещева Н.А., Валуев И.Л., Валуев Л.И. Биоцидные сополимеры метакрилоилгуанидин гидрохлорида с метакриламидом и диаллилдиметиламмоний хлоридом//Высокомолекулярны есоединения (серия Б). 2021. Т. 63. N 5. P. 340−344. https://doi.org/10.31857/S2308113921050132.</mixed-citation><mixed-citation xml:lang="en">Sivov N.A., Kleshcheva N.A., Valuev I.L., Valuev L.I. Biocidal copolymers of methacryloylguanidine hydrochloride with methacrylamide and diallyldimethylammonium chloride. Vysokomolekuljarnye soedinenija (serija B) = Polymer Science, Series B. 2021;63(5):531-535. (In Russian). https://doi.org/10.31857/S2308113921050132.</mixed-citation></citation-alternatives></ref><ref id="cit3"><label>3</label><citation-alternatives><mixed-citation xml:lang="ru">Chen A., Er G., Zhang Ch., Tang J., Alam M., Hang T.T., et al. Antimicrobial anilinium polymers: the properties of poly(N,N-dimethylaminophenylenemethacrylamide) in solution and as coatings // Journal of Polymer Science. Part A: Polymer Chemistry. 2019. Vol. 57, no. 18. P. 1908–1921. https://doi.org/10.1002/pola.29314.</mixed-citation><mixed-citation xml:lang="en">Chen A., Er G., Zhang Ch., Tang J., Alam M., Hang T.T., et al. Antimicrobial anilinium polymers: the properties of poly(N,N-dimethylaminophenylenemethacrylamide) in solution and as coatings. Journal of Polymer Science. Part A: Polymer Chemistry. 2019;57(18):19081921. https://doi.org/10.1002/pola.29314.</mixed-citation></citation-alternatives></ref><ref id="cit4"><label>4</label><citation-alternatives><mixed-citation xml:lang="ru">Малкандуев Ю.А., Хаширова С.Ю., Сарбашева А.И., Байдаева М.Х., Мартыненко А.И., Попова Н.И. [и др.]. Структура гуанидинсодержащих (со)полимеров и их биоцидные и токсические свойства // Известия вузов. Северо-кавказский регион. Серия: Естественные науки. 2012. N 2. C. 71−75. EDN: OXHTSD.</mixed-citation><mixed-citation xml:lang="en">MalkanduevYu.A.,KhashirovaS.Yu.,Sarbasheva A.I., Baydaeva M.K., Martynenko A.I., Popova N.I., et al. Structure of guanidine containing (co) polymers and their biocide and toxic properties. Izvestija vuzov. Severo-kavkazskij region. Serija: Estestvennye nauki = Bulletin of Higher Educational Institutions. North Caucasus Region. Natural Sciences. 2012;(2):71-75. (In Russian). EDN: OXHTSD.</mixed-citation></citation-alternatives></ref><ref id="cit5"><label>5</label><citation-alternatives><mixed-citation xml:lang="ru">Мусаев Ю.И., Мусаева Э.Б., Киржинова И.Х. Новые соединения на основе гуанидина и аминогуанидина // Фундаментальные исследования. 2011. N 12. C. 143−146. EDN: OFYRLN.</mixed-citation><mixed-citation xml:lang="en">Musaev Y.I., Musaeva E.B., Kirzhinova I.K. NOVEL Compositions on the basis of guanidine and aminoguanidine. Fundamental’nye issledovanija. 2011;(12):143-146. (In Russian). EDN: OFYRLN.</mixed-citation></citation-alternatives></ref><ref id="cit6"><label>6</label><citation-alternatives><mixed-citation xml:lang="ru">Kanth S., Puttaiahgowda Y.M., Nagaraja A., Bukva M. Recent advances in development of poly (dimethylaminoethyl methacrylate) antimicrobial polymers // European Polymer Journal. 2022. Vol. 163. P. 110930. https://doi.org/10.1016/j.eurpolymj.2021.110930.</mixed-citation><mixed-citation xml:lang="en">Kanth S., Puttaiahgowda Y.M., Nagaraja A., Bukva M. Recent advances in development of poly (dimethylaminoethyl methacrylate) antimicrobial polymers. European Polymer Journal. 2022;163:110930. https://doi.org/10.1016/j.eurpolymj.2021.110930.</mixed-citation></citation-alternatives></ref><ref id="cit7"><label>7</label><citation-alternatives><mixed-citation xml:lang="ru">Tolosa J., Heras G.S., Carrión B., Segura T., Páez P.L., de Lera-Garrido F.J., et al. Structure-activity relationships for poly(phenylene)vinylene derivatives as antibacterial agents // Chemistry Select. 2018. Vol. 3. P. 7327. https://doi.org/10.1002/slct.201801287.</mixed-citation><mixed-citation xml:lang="en">Tolosa J., Heras G.S., Carrión B., Segura T., Páez P.L., de Lera-Garrido F.J., et al. Structure-activity relationships for poly(phenylene)vinylene derivatives as antibacterial agents. Chemistry Select. 2018;3:7327. https://doi.org/10.1002/slct.201801287.</mixed-citation></citation-alternatives></ref><ref id="cit8"><label>8</label><citation-alternatives><mixed-citation xml:lang="ru">Bazanov D.R., Pervushin N.V., Savitskaya V.Yu., Anikina L.V., Proskurnina M.V., Lozinskaya N.A., et al. 2,4,5-Tris(alkoxyaryl)imidazoline derivatives as potent scaffold for novel p53-MDM2 interaction inhibitors: design, synthesis, and biological evaluation // Bioorganic and Medicinal Chemistry Letters. 2019. Vol. 29, no. 16. P. 2364–2368. https://doi.org/10.1016/j.bmcl.2019.06.007.</mixed-citation><mixed-citation xml:lang="en">Bazanov D.R., Pervushin N.V., Savitskaya V.Yu., Anikina L.V., Proskurnina M.V., Lozinskaya N.A., et al. 2,4,5-Tris(alkoxyaryl)imidazoline derivatives as potent scaffold for novel p53-MDM2 interaction inhibitors: design, synthesis, and biological evaluation. Bioorganic and Medicinal Chemistry Letters. 2019;29(16):2364-2368. https://doi.org/10.1016/j.bmcl.2019.06.007.</mixed-citation></citation-alternatives></ref><ref id="cit9"><label>9</label><citation-alternatives><mixed-citation xml:lang="ru">Лавров Н.А. Синтез, модификация и применение медицинских полимеров на основе N-винилсукцинимида (обзор) // Известия Санкт-Петербургского технологического института (Технического университета). 2018. N 46. C. 68–75. EDN: YTDYAP.</mixed-citation><mixed-citation xml:lang="en">Lavrov N.A. Synthesis, modification and use of medical polymers based on n-vinylsuccinimide (review). Izvestija Sankt-Peterburgskogo tehnologicheskogo instituta (Tehnicheskogo universiteta). 2018;(46):68-75. (In Russian). EDN: YTDYAP.</mixed-citation></citation-alternatives></ref><ref id="cit10"><label>10</label><citation-alternatives><mixed-citation xml:lang="ru">Yang Y., Cai Z., Huang Z., Tang X., Zhang X. Antimicrobial cationic polymers: from structural design to functional control // Polymer Journal. 2018. Vol. 50. P. 33–44. https://doi.org/10.1038/pj.2017.72.</mixed-citation><mixed-citation xml:lang="en">Yang Y., Cai Z., Huang Z., Tang X., Zhang X. Antimicrobial cationic polymers: from structural design to functional control. Polymer Journal. 2018;50:33-44. https://doi.org/10.1038/pj.2017.72.</mixed-citation></citation-alternatives></ref><ref id="cit11"><label>11</label><citation-alternatives><mixed-citation xml:lang="ru">Шальнова Л.И., Лавров Н.А. Получение и перспективы применения сополимеров гидразида N-винилсукцинаминовой кислоты как носителя биофункциональных веществ направленного действия // Пластические массы. 2019. N 9-10. C. 8–10. EDN: HSURLT. https://doi.org/10.35164/0554-2901-2019-9-10-8-10.</mixed-citation><mixed-citation xml:lang="en">Shal’nova L.I., Lavrov N.A. Obtaining and prospects for the use of hydrazide N-vinylsuccinamic acid copolymers as a carrier of biofunctional substances with directional effect. Plasticheskie massy. 2019; (9-10):8-10. (In Russian). EDN: HSURLT. https://doi.org/10.35164/0554-2901-2019-9-10-8-10.</mixed-citation></citation-alternatives></ref><ref id="cit12"><label>12</label><citation-alternatives><mixed-citation xml:lang="ru">Gingasu D., Mindru I., Patron L., Ianculescu A., Vasile E., Marinescu G., et al. Synthesis and characterization of chitosan-coated cobalt ferrite nanoparticles and their antimicrobial activity // Journal of Inorganic and Organometallic Polymers and Materials. 2018. Vol. 28, no. 5. P. 1932–1941. https://doi.org/10.1007/s10904-018-0870-3.</mixed-citation><mixed-citation xml:lang="en">Gingasu D., Mindru I., Patron L., Ianculescu A., Vasile E., Marinescu G., et al. Synthesis and characterization of chitosan-coated cobalt ferrite nanoparticles and their antimicrobial activity. Journal of Inorganic and Organometallic Polymers and Materials. 2018;28(5):1932-1941. https://doi.org/10.1007/s10904-018-0870-3.</mixed-citation></citation-alternatives></ref><ref id="cit13"><label>13</label><citation-alternatives><mixed-citation xml:lang="ru">Lee D., Lee Y.M., Jeong Ch., Lee J., Kim W.J. Bioreducible guanidinylated polyethylenimine for efficient gene delivery // ChemMedChem. 2014. Vol. 9, no. 12. P. 2718–2724. https://doi.org/10.1002/cmdc.201402293.</mixed-citation><mixed-citation xml:lang="en">Lee D., Lee Y.M., Jeong Ch., Lee J., Kim W.J. Bioreducible guanidinylated polyethylenimine for efficient gene delivery. ChemMedChem. 2014;9(12):2718-2724. https://doi.org/10.1002/cmdc.201402293.</mixed-citation></citation-alternatives></ref><ref id="cit14"><label>14</label><citation-alternatives><mixed-citation xml:lang="ru">Menyashev M.R., Gerasin V.A., Guseva M.A., Merekalova N.D., Martynenko A.I., Sivov N.A. trans-Polyisoprene-based modified flaky silicates and nanocomposites with biocidal properties // Polymer Science, Series B: Chemistry. 2016. Vol. 58, no. 2. P. 226–234. https://doi.org/10.1134/S1560090416020032.</mixed-citation><mixed-citation xml:lang="en">Menyashev M.R., Gerasin V.A., Guseva M.A., Merekalova N.D., Martynenko A.I., Sivov N.A. trans-Polyisoprene-based modified flaky silicates and nanocomposites with biocidal properties. Polymer Science, Series B: Chemistry. 2016;58(2):226-234. https://doi.org/10.1134/S1560090416020032.</mixed-citation></citation-alternatives></ref><ref id="cit15"><label>15</label><citation-alternatives><mixed-citation xml:lang="ru">Tashiroa T. Antibacterial and bacterium adsorbing macromolecules // Macromolecular Materials and Engineering. 2001. Vol. 286, no. 2. P. 63–87. https://doi.org/10.1002/14392054(20010201)286:2&lt;63::AID-MAME63&gt;3.0.CO;2-H.</mixed-citation><mixed-citation xml:lang="en">Tashiroa T. Antibacterial and bacterium adsorbing macromolecules. Macromolecular Materials and Engineering. 2001;286(2):63-87. https://doi.org/10.1002/14392054(20010201)286:2&lt;63::AID-MAME63&gt;3.0.CO;2-H.</mixed-citation></citation-alternatives></ref><ref id="cit16"><label>16</label><citation-alternatives><mixed-citation xml:lang="ru">Muñoz-Bonilla A., Cerrada M.L., Fernández-Garsía M. Polymeric materials with antimicrobial activity: from synthesis to applications. RSC Publishing, 2014. P. 1–21.</mixed-citation><mixed-citation xml:lang="en">Muñoz-Bonilla A., Cerrada M.L., Fernández-Garsía M. Polymeric materials with antimicrobial activity: from synthesis to applications. RSC Publishing; 2014, p. 1-21.</mixed-citation></citation-alternatives></ref><ref id="cit17"><label>17</label><citation-alternatives><mixed-citation xml:lang="ru">Chambers H.F., De Leo F.R. Waves of resistance: Staphylococcus aureus in the antibiotic era // Nature Review Microbiology. 2009. Vol. 7, no. 9. P. 629–641. https://doi.org/10.1038/nrmicro2200.</mixed-citation><mixed-citation xml:lang="en">Chambers H.F., De Leo F.R. Waves of resistance: Staphylococcus aureus in the antibiotic era. Nature Review Microbiology. 2009;7(9):629-641. https://doi.org/10.1038/nrmicro2200.</mixed-citation></citation-alternatives></ref><ref id="cit18"><label>18</label><citation-alternatives><mixed-citation xml:lang="ru">Гембицкий П.А., Воинцева И.И. Полимерный биоцидный препарат полигексаметиленгуанидин. Запорожье: Полиграф, 1998. 42 с.</mixed-citation><mixed-citation xml:lang="en">Gembickij P.A., Voinceva I.I. Polymer biocydia polygexamethylenguanidine. Zaporozh’e: Poligraf; 1998, 42 p. (In Russian).</mixed-citation></citation-alternatives></ref><ref id="cit19"><label>19</label><citation-alternatives><mixed-citation xml:lang="ru">Menyashev M.R., Gerasin V.A., Martynenko A.I., Kleshcheva N.A., Popova N.I., Sivov N.A. Features of reactions of radical (co)polymerization of methacryloylguanidine trifluoroacetate in various solvents // Polymer Science, Series B: Chemistry. 2017. Vol. 59, no. 6. P. 650–654. https://doi.org/10.1134/S1560090417060057.</mixed-citation><mixed-citation xml:lang="en">Menyashev M.R., Gerasin V.A., Martynenko A.I., Kleshcheva N.A., Popova N.I., Sivov N.A. Features of reactions of radical (co)polymerization of methacryloylguanidine trifluoroacetate in various solvents. Polymer Science, Series B: Chemistry. 2017;59(6):650-654. https://doi.org/10.1134/S1560090417060057.</mixed-citation></citation-alternatives></ref><ref id="cit20"><label>20</label><citation-alternatives><mixed-citation xml:lang="ru">Лачинов М.Б., Королев Б.А., Древаль В.Е., Череп Е.И., Зубов В.П., Кабанов В.А. Связь автоускорения при радикальной полимеризации // Высокомолекулярные соединения. 1982. Т. 24А. N 10. С. 2220–2226.</mixed-citation><mixed-citation xml:lang="en">Lachinov M.B., Korolev B.A., Dreval’ V.E., Cherep E.I., Zubov V.P., Kabanov V.A. The connection of auto performance in radical polymerization. Vysokomolekuljarnye soedinenija. 1982;24А(10):2220-2226. (In Russian).</mixed-citation></citation-alternatives></ref></ref-list><fn-group><fn fn-type="conflict"><p>The authors declare that there are no conflicts of interest present.</p></fn></fn-group></back></article>
