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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Исследование кинетики генерирования пероксильных радикалов потенциометрическим методом модели 2,2'-азобис(2-метилпропионамидин)дигидрохлорида : магистерская диссертация / Investigation of the kinetics of generation and inhibitory action of peroxy radicals by potentiometric method on the 2,2'-azobis (2-methylpropionamidine) dihydrochloride (AARH) model

Давлетчурина, А. Г., Davletchurina, A. G. January 2017 (has links)
The aim of this work is to study the kinetics of generation and inhibitory action of peroxy radicals by the potentiometric method on the 2,2'-azobis (2-methylpropionamidine) dihydrochloride (AAРH) model. The paper describes the causes and the effects of free radicals in the human body, the body's antioxidant system and methods for determining antioxidant / antiradical activity. In the course of the work, the kinetic parameters of the AAPH reaction with hexacyanoferrate (II) of potassium were studied by a potentiometric method. / Целью данной работы является исследование кинетики генерирования и ингибирующего действия пероксильных радикалов потенциометрическим методом на модели 2,2'-азобис(2-метилпропионамидин) дигидрохлорида (ААРН). В работе описаны причины возникновения и действия свободных радикалов в организме человека, антиоксидантная система организма и методы определения антиоксидантной/антирадикальной активности. В процессе работы исследованы кинетические параметры реакции ААРН с гексацианоферратом (II) калия потенциометрическим методом.
22

Исследование антиоксидантных свойств препаратов сочетанного действия : магистерская диссертация / Study of antioxidant properties of combined action

Борисова, М. В., Borisova, M. V. January 2021 (has links)
Целью выпускной квалификационной работы является комплексное исследование интегральных антиоксидантных параметров препаратов комбинированного действия для терапии вирусных и нейродегенеративных заболеваний. Были изучены пути образования свободных радикалов, рассмотрены антиоксидантные подходы в терапии различных заболеваний. С использованием предложенных потенциометрических методов была исследована антиоксидантная (АОЕ) и антирадикальная (АРЕ) емкость синтезированных триазолов и имидазолов, модифицированных полифенолами. АОЕ определяли потенциометрическим методом с использованием окислителя нерадикальной природы – K3[Fe(CN)6]/K4[Fe(CN)6], АРЕ оценивали потенциометрическим методом с использованием радикал-генерирующей системы 2,2´-азобис(2-метилпропионамидин) дигидрохлорида (ААРН). Стехиометрические коэффициенты ингибирования изученных триазолов принимают значения от 0 до 15, имидазолов от 0 до 5 в зависимости от количества активных групп в молекуле антиоксиданта, их расположением и с механизмом обрыва цепей на антиоксиданте. Были проведены корреляционные исследования с применением независимых спектрофотометрических методов. / Objective of the work: comprehensive study of integral antioxidant parameters of combined action drugs for the treatment of viral and neurodegenerative diseases. We have considered ways to form free radicals and antioxidant approaches in therapy of various diseases. In the process of work we investigated the antioxidant parameters adducts of triazole and imidazoles modified with polyphenols. Particularly, the determination of antioxidant capacity with oxidizing agents of a radical (2,2'-azobis (2-methylpropionamidine) dihydrochloride (AAPH)) and non-radical nature (K3[Fe(CN)6]/K4[Fe(CN)6) was performed by using the potentiometric method. Stoichiometric inhibition coefficients of the studied triazoles take values from 0 to 15, imidazoles – from 0 to 5, depending on the number of active groups in the antioxidant molecule, their location and the mechanism of chain termination on the antioxidant. Spectrophotometric studies were carried out using the reactions of the interaction of antioxidants with a stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and reagent Folin-Ciocalteu to confirm the correctness of the results.
23

Новые подходы к потенциометрическому определению антирадикальной емкости с учетом кинетических особенностей взаимодействия антиоксидантов с пероксильными радикалами : магистерская диссертация / New approaches to the potentiometric determination of the antiradical capacity, taking into account the kinetic features of the interaction of antioxidants with peroxyl radicals

Игдисанова, Д. И., Igdisanova, D. I. January 2022 (has links)
Целью выпускной квалификационной работы является разработка нового потенциометрического подхода к исследованию антирадикальных свойств соединений с учетом кинетических особенностей взаимодействия антиоксидантов с пероксильными радикалами. В работе рассмотрены причины возникновения окислительного стресса, система антиоксидантной защиты и существующие методы исследования антиоксидантных/антирадикальных свойств соединений. Разработан новый потенциометрический подход к исследованию антирадикальных свойств соединений, учитывающий кинетические особенности реакции антиоксидантов с генерируемыми пероксильными радикалами. Предложенным способом оценена константа взаимодействия с пероксильными радикалами (k3) растворов индивидуальных антиоксидантов «быстрого» и «медленного» действия. Предложен новый потенциометрический способ исследования антирадикальных свойств соединений, заключающийся в расчете площади над кривой кинетической зависимости Exp(∆E). Предложенным способом рассчитаны площади SАРЕ для «быстрых» и «медленных» антиоксидантов, в том числе с особенностью кинетики превращения. / The aim of the final qualifying work is to develop a new potentiometric approach to the study of the antiradical properties of compounds, taking into account the kinetic features of the interaction of antioxidants with peroxyl radicals. The paper considers the causes of oxidative stress, the system of antioxidant protection and existing methods for studying the antioxidant/antiradical properties of compounds. A new potentiometric approach to the study of the antiradical properties of compounds has been developed, taking into account the kinetic features of the reaction of antioxidants with generated peroxyl radicals. The proposed method estimates the constant of interaction with peroxyl radicals (k3) of solutions of individual antioxidants of "fast" and "slow" action. A new potentiometric method for studying the antiradical properties of compounds is proposed, which consists in calculating the area above the kinetic dependence curve Exp(∆E). By the proposed method, the SARE areas for "fast" and "slow" antioxidants are calculated, including those with a feature of the kinetics of transformation.
24

Biološka aktivnost i hemijski sastav ekstrakata odabranih autohtonih makrogljiva / Biological activity and chemical caracteristics  of selected extracts of  autochtonous macrofungi

Janjušević Ljiljana 18 September 2017 (has links)
<p>Prema postavljenim ciljevima u ovoj doktorskoj disertaciji sakupljeno je i&nbsp;<br />determinisano&nbsp;ukupno&nbsp;sedam&nbsp;vrsta&nbsp;autohtonih&nbsp;gljiva&nbsp;sa&nbsp;područja&nbsp;Fru&scaron;ke&nbsp;gore, Tare i&nbsp; Vr&scaron;ačkog brega, pet lignikolnih&nbsp;‐&nbsp;<em>Bjerkandera adusta</em>,&nbsp;<em>Pleurocybella&nbsp; porrigens</em>,&nbsp;St<em>ereum&nbsp;hirsutum,&nbsp;Stereum&nbsp;subtomentosum</em>&nbsp;i&nbsp;Trametes&nbsp;versicolor,&nbsp;i&nbsp;<br />dve&nbsp; terikolne&nbsp;‐&nbsp;<em>Amanita&nbsp; strobiliformis</em>&nbsp;i Hydnum repandum. Utvrđena je&nbsp; njihova&nbsp;biolo&scaron;ka&nbsp;aktivnost&nbsp;(antiradikalska,&nbsp;antioksidativna,&nbsp;antimikrobna,&nbsp;anti‐acetilholinesterazna&nbsp;i&nbsp;citotokisčna)&nbsp;spram&nbsp;hemijskog&nbsp;sastava&nbsp;njihovih&nbsp;vodenih&nbsp;<br />(H<sub>2</sub>O),&nbsp;etanolnih&nbsp;(EtOH),&nbsp;metanolnih&nbsp;(MeOH)&nbsp;i&nbsp;polisaharidnih&nbsp;(PSH)&nbsp;ekstrakata.&nbsp;<br />Analiza&nbsp;hemijskog&nbsp;sastava&nbsp;odabranih&nbsp;vrsta&nbsp;uključila&nbsp;je&nbsp;određivanje&nbsp;hemijske&nbsp;<br />karakterizacije&nbsp;PSH&nbsp;ekstrakata&nbsp;‐&nbsp;FTIR&nbsp;analizom,&nbsp;određivanje&nbsp;fenolnog&nbsp;profila&nbsp;‐&nbsp;<br />HPMC/MS‐MS,&nbsp;sadržaja&nbsp;organskih&nbsp;kiselina&nbsp;‐&nbsp;HPLC,&nbsp;sadržaja&nbsp;masnih&nbsp;kiselina&nbsp;‐&nbsp;<br />GC‐FID&nbsp;i&nbsp;sadržaja&nbsp;biogenih&nbsp;elemenata&nbsp;‐&nbsp;AAS.&nbsp;Spektrofotometrijskim&nbsp;metodama<br />određen je ukupan sadržaj proteina i ukupan sadržaj fenola i flavonoida.&nbsp;<br />Prema&nbsp;antiradikalskoj&nbsp;aktivnosti&nbsp;OH<sup>&bull; ,&nbsp;</sup>O2<sup>&bull;‐</sup>,&nbsp;OH<sup>&bull;</sup>,&nbsp;Asc<sup>&bull;</sup>,&nbsp;DPPH<sup>&bull;&nbsp;</sup> i&nbsp;ABTS<sup>&bull;+</sup>&nbsp;izdvojili&nbsp;<br />su&nbsp; se&nbsp; ekstrakti lignikolnih vrsta:&nbsp; MeOH ekstrakt vrste&nbsp;<em>P. porrigens</em>, H<sub>2</sub>O&nbsp; ekstrakt&nbsp;<em>P.&nbsp;porrigens</em>,&nbsp;MeOH&nbsp;ekstrakt&nbsp;<em>T.&nbsp;versicolor</em>,&nbsp;H<sub>2</sub>O&nbsp;ekstrakt&nbsp;<em>S.&nbsp;hirsutum, </em>MeOH&nbsp;ekstrakt&nbsp;<em>S.&nbsp;subtomentosum</em>&nbsp;i&nbsp;H<sub>2</sub>O&nbsp;ekstrakt&nbsp;<em>B.&nbsp;adusta</em>,&nbsp;navedenim&nbsp;redom.&nbsp;<br />Najjaču antioksidativnu aktivnost dobijenu FRAP i polarografskom HPMC&nbsp;<br />metodom ispoljili su PSH i H<sub>2</sub>O ekstrakti terikolne vrste&nbsp;<em>A. strobiliformis</em>.&nbsp;<br />Antimikrobna aktivnost analiziranih ekstrakata određena je ispitivanjem&nbsp;<br />antibakterijskog,&nbsp;antifungalnog&nbsp;i&nbsp;antiviralnog&nbsp;potencijala,&nbsp;pri&nbsp;čemu&nbsp;se&nbsp;izdvojila&nbsp;<br />vrsta&nbsp;<em> H.&nbsp; repandum</em>&nbsp;ispoljavajući najbolji efekat na Gram‐pozitivne i Gram‐<br />negativne bakterije i na sve analizirane fitopatogene izolate&nbsp;<em>(Fusarium&nbsp;</em>i&nbsp;<br />Alternaria)&nbsp;i<em>&nbsp;T.&nbsp;versicolor</em>&nbsp;na&nbsp;analizirani&nbsp;bakteriofag.&nbsp;Anti‐acetilholinesterazna&nbsp;<br />aktivnost određena je testovima in solid i in liquid, a najbolji procenat&nbsp;<br />inhibicije AChE ispoljili su EtOH ekstrakti vrsta&nbsp;<em>S. hirsutum</em>,&nbsp;<em>B. adusta</em>,&nbsp;<em>S</em>.&nbsp;<br /><em>subtomentosum</em>&nbsp;i&nbsp;<em>T.&nbsp;versicolor</em>.&nbsp;Citotoksična&nbsp;aktivnost&nbsp;ekstrakata&nbsp;određena&nbsp;je&nbsp;<br />MTT testom, a prema najboljoj ispoljenoj aktivnosti izdvojili su se MeOH&nbsp;<br />ekstrakt<em>&nbsp;P.&nbsp;porrigens&nbsp;</em>i&nbsp;ekstrakti<em>&nbsp;B.&nbsp;adusta</em>,&nbsp;H<sub>2</sub>O&nbsp;i&nbsp;EtOH.&nbsp;Citotoksična&nbsp;aktivnost&nbsp;<br />ovih&nbsp;lignikolnih&nbsp;vrsta&nbsp;naročito&nbsp;je&nbsp;izražena&nbsp;nakon&nbsp;72&nbsp;h.&nbsp;Na&nbsp;osnovu&nbsp;dobijenih&nbsp;<br />rezultata, gde su se istakle različite vrste i njihovi različiti ekstrakti u&nbsp;<br />primenjenim&nbsp;testovima,&nbsp;jasno&nbsp;je&nbsp;da&nbsp;biolo&scaron;ka&nbsp;aktivnost&nbsp;i&nbsp;hemijski&nbsp;sastav&nbsp;zavise&nbsp;<br />od&nbsp;porekla,&nbsp;vrste&nbsp;i&nbsp;tipa&nbsp;ekstrakta&nbsp;analiziranih&nbsp;gljiva.&nbsp;Na&nbsp;osnovu&nbsp;tipa&nbsp;rastvarača&nbsp;<br />odnosno ekstrakata vrsta, koje su pokazale najbolju aktivnost spram pomenutih&nbsp; testova i na osnovu dobijenih korelacija kao i na osnovu detektovanih jedinjenja,&nbsp; pretpostavljamo da su za ispoljene aktivnosti u najvećoj meri odgovorna fenolna&nbsp; jedinjenja&nbsp;i&nbsp;polisaharidi.&nbsp;&nbsp;<br />&nbsp;<br />Ispoljeni&nbsp;biopotencijal&nbsp;analiziranih&nbsp;vrsta&nbsp;gljiva&nbsp;upućuje&nbsp;na&nbsp;njihovu&nbsp;potencijalnu&nbsp;<br />upotrebu kao funkcionalne hrane i nutraceutika, kao i u biokontroli&nbsp;<br />fitopatogena.</p> / <p>According&nbsp; to&nbsp; the&nbsp; set&nbsp; aims&nbsp; of&nbsp; the&nbsp; presented&nbsp; PhD&nbsp; thesis,&nbsp; seven&nbsp; autochthonous fungal species from the region of Fruska Gora, Tara&nbsp; and Vr&scaron;ac Mountains were collected and determined: five lignicolous ‐ <em>Bjerkandera&nbsp; adusta,&nbsp; Pleurocybella&nbsp; porrigens,&nbsp; Stereum&nbsp; hirsutum,&nbsp; Stereum subtomentosum and Trametes versicolor</em>, and two terricolous ‐ <em>Amanita strobiliformis </em>and <em>Hydnum repandum</em>. Biological activity of these&nbsp; species&nbsp; (antiradical,&nbsp; antioxidant,&nbsp; antimicrobial,&nbsp; anti‐ acetylcholinesterase and cytotoxic) was determined in relation to the chemical composition of the extracts, aqueous (H<sub>2</sub>O), ethanolic (EtOH), methanolic (MeOH) and polysaccharide (PSH). Analysis of the chemical content of analyzed species included chemical characterization of PSH extracts&nbsp; &ndash;&nbsp; by&nbsp; FTIR&nbsp; analysis,&nbsp; determination&nbsp; of&nbsp; phenolic&nbsp; profile ‐ by HPMC/MS‐MS, content of organic acids ‐ by HPLC, fatty acid content ‐ by&nbsp; GC‐FID&nbsp; and&nbsp; content&nbsp; of&nbsp; biogenic&nbsp; elements ‐ by&nbsp; AAS. Spectrophotometric methods were applied for determination of the content of total proteins, polyphenols and flavonoids. According to the antiradical activity obtained towards OH<sup>&bull;</sup>, О2<sup>&bull;‐</sup>, OH<sup>&bull;</sup>, Asc<sup>&bull;</sup>, DPPH<sup>&bull;</sup>&nbsp;and ABTS<sup>&bull;+</sup> extracts of lignicolous species were singled out: <em>P. porrigens&nbsp;</em> (MeOH&nbsp; extract),&nbsp;<em> P.&nbsp; porrigens</em>&nbsp; (H<sub>2</sub>O&nbsp; extract),&nbsp;<em>T. versicolor</em>&nbsp;(MeOH&nbsp;&nbsp; extract),<em> S. hirsutum </em>(H<sub>2</sub>O extract), <em>S. subtomentosum</em> (MeOH extract) and&nbsp;<em>B. austa</em> (H<sub>2</sub>O&nbsp; extract),&nbsp; respectively. The&nbsp; highest antioxidant activity obtained by FRAP and the polarographic HPMC method was exhibited&nbsp; for PSH&nbsp; and&nbsp; H<sub>2</sub>O extracts of the terricolous species&nbsp;<em>A. strobiliformis</em>. The intimicrobial activity of analyzed extracts was determined by examination of antibacterial, antifungal and antiviral potentials, whereby&nbsp; the species&nbsp; <em>H.&nbsp; repandum&nbsp;</em>was separated by exhibiting the best effect on Gram‐positive&nbsp; and Gram‐negative bacteria, and all the analyzed hytopathogenic isolates (<em>Fusarium, Alternaria</em>)&nbsp; and <em>T. versicolor</em>&nbsp;against analyzed bacteriophage. Anti‐cetylcholinesterase activity was determined by tests in solid and in liquid, while the best&nbsp; percent of AChE inhibition was showed by EtOH extracts of the species <em>S. hirsutum, B. adusta, S. subtomentosum </em>and <em>T. versicolor</em>.bThe cytotoxic activity of extracts was determined by MTT assay, and according to the best activity, the MeOH extract of <em>P. porrigens</em>, and H<sub>2</sub>O and EtOH extracts of <em>B. adusta</em>&nbsp;were distinguished particularly after 72 h. Based on the results obtained, favoring different species and their different extracts in the applied tests, it is clear that the biological activity and chemical composition depend on the origin, species and type of extract of the analyzed fungi. Based on the type of solvent or extract of the species that showed the best activity in relation to the above tests and on the basis of the obtained correlations as well as on&nbsp; the basis of the detected compounds, we assume&nbsp; that&nbsp; the&nbsp; phenol compounds&nbsp; and&nbsp; polysaccharides&nbsp; are responsible for the activities performed.<br />Demonstrated bio‐potential of analyzed fungal species indicates their&nbsp; potential use as functional foods and nutraceutics, as well as in the biocontrol of phytopathogens.</p>

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