Radiation-chemical synthesis of thermo- and pH-sensitive antibacterial silver/poly(N-isopropilacrylamide-co-itaconic acid) nanocomposites.

U okviru ove doktorske disertacije izvedena je radijaciono-hemijska sinteza i karakterizacija novih nanokompozita na bazi umreţenih polimernih matrica N-izopropilakrilamida (NiPAAm) i itakonske kiseline (IK) i nanočestica srebra (Ag/P(NiPAAm/IK)). Za sintezu nanokompozita je korišćena radiolitička metoda koja omogućava umreţavanje i fino podešavanje svojstava nosača tj. polimerne matrice, ali i formiranje nanočestica srebra ţeljenih svojstava unutar polimerne matrice (in situ sinteza). Radiolitička metoda sinteze je izvedena pod dejstvom gama zračenja na kobaltnom (60Co) izvoru. Sintetisani uzorci su podvrgnuti detaljnoj fizičko-hemijskoj karakterizaciji u cilju dobijanja informacija o polimernim matricama kao nosačima i nanočesticama srebra kao nanopuniocima, ali i u cilju ispitivanja njihovog sinergističkog dejstva u nanokompozitnim sistemima. Morfologija umreţenih sistema je ispitana primenom skenirajuće elektronske mikroskopije (SEM) i mikro kompjuterizovane topografije (mikro-CT), a studija bubrenja praćenjem kinetike bubrenja u medijumima različitih pH-vrednosti i temperature, pri čemu su simulirani fiziološki uslovi. Utvrđeno je da prisustvo itakonske kiseline i inkorporacija nanočestica srebra utiču na morfologiju nanokompozita, parametre polimerne mreţe, kao i na kapacitet bubrenja. Optička svojstva nanokompozita su ispitana metodom spektroskopije u ultraljubičastoj i vidljivoj oblasti spektra (UV-Vis) i teorijskim modelovanjem primenom MiePlot 3.4 programskog paketa čiji je algoritam zasnovan na Mie-ovoj teoriji. U apsorpcionim spektrima je zapaţena karakteristična plazmonska apsorpcija sa maksimumom u opsegu od 390 nm do 412 nm, dok je modelovanjem određeno da se vrednost prečnika nanočestica srebra kreće između 6,8 nm i 16,2 nm...In this study, radiation-chemical synthesis and characterization of the novel nanocomposite systems based on silver nanoparticles (AgNPs) and crosslinked copolymer matrix of N-isopropylacrylamide (NiPAAm) and itaconic acid (IA) (Ag/P(NiPAAm/IA)) were performed. Radiolytic method, which is used for synthesis, enables fine tuning of properties of polymer matrix as a carrier, as well as formation of the silver nanoparticles with desired properties within polymer matrix (in situ synthesis). The radiolytic synthesis method is carried out by gamma irradiation at a cobalt (60Co) radiation facility. Synthesized samples were undergo to detailed physico-chemical characterization in order to obtain information about polymer matrix as a carrier and silver nanoparticles as a nanofillers, but also to examine their synergistic effects in the nanocomposite systems. Morphology of the crosslinked systems was performed by scanning electron microscopy (SEM) and micro computerized topography (micro-CT), while swelling study was performed by monitoring the swelling kinetics in the swelling media with different pH and temperature, i.e. in simulated physiological conditions. It has been shown that the addition of itaconic acid and incorporation of AgNPs have influences on the morphology, network parameters as well as on the swelling capacity. The optical properties of the nanocomposites were investigated by ultraviolet–visible spectroscopy (UV-Vis) and theoretical modeling using MiePlot 3.4 software package, with algorithm based on Mie's theory. Obtained absorption spectra exhibit the characteristic plasmon peak with maxima between 390 nm and 412 nm, while the modeling has shown that the mean size of the silver nanoparticles was in the range between 6.8 nm and 16.2 nm..

Društvene promene, Bolonjski proces i treća misija Univerziteta u Srbiji

The expectations that the society and its different segments have from the university are influenced by historical circumstances and social, economic, political and cultural environment as the widest context within which the university interacts with its surroundings. Having this in mind, this paper aims to identify and analyze the explicit and implicit needs articulated by different social actors towards Serbian universities. This is done with an understanding that these needs arise in the context of comprehensive and deep social (economic, cultural, political) transition. The ‘third mission’ of the university, which includes the university participation in economic development as well as in building the civil society and democratic values, is considered to be especially important in the transition period. However, this mission is least present in practice given the fact that Serbian universities are so overburdened by other new roles in scientific research and education that they do not manage to systematically and strategically formulate their tasks within this new mission.Očekivanja koje društvo i različiti segmenti društva imaju od univerziteta uslovljena su istorijskim okolnostima i društvenim, ekonomskim, političkim i kulturnim ambijentom kao najširim kontekstom unutar kog univerzitet stupa u interakcije sa okruženjem. Imajući ovo u vidu, u radu se uočavaju i analiziraju eksplicitne i implicitne potrebe koje različiti društveni akteri artikulišu prema univerzitetima u Srbiji, uz razumevanje da ove potrebe nastaju u okolnostima sveobuhvatne i duboke društvene (ekonomske, kulturne, političke) tranzicije. Konstatuje se da je 'treća misija' univerziteta, koja se ogleda u učešću univerziteta u ekonomskom razvoju i u izgradnji civilnog društva i demokratskih vrednosti, posebno važna u tranzicionom periodu. Međutim, ona je najmanje zastupljena pošto su univerziteti previše opterećeni drugim novim zadacima u nauci i nastavi da bi sistematično i strateški formulisali svoju ulogu u okviru ove nove misije

Bukom protiv diktature: borba za simboličko predstavljanje

U ovom radu analiziramo proces (političkog) predstavljanja iz ugla simbola kao subjekata reprezentacije. Fokusirajući se na slučaj protesta Bukom protiv diktature održanog širom Srbije na proleće 2020. godine, istražujemo kako simboli zauzimaju ulogu predstavnika, kako se kreiraju i menjaju značenja simbola i kako ovi procesi utiču na kreiranje identiteta predstavljenih, nas i Drugih. Za razliku od tradicionalnog politikološkog razumevanja simboličkog predstavljanja kao statičnog i pasivnog, u radu pokazujemo da su značenja simbola promenjiva, da nastaju i menjaju se kao rezultat odnosa moći, ubeđivanja i osporavanja. Koristeći metodu analize predstavničkih tvrdnji, simboličko predstavljanje tokom građanskih protesta analiziramo kroz medijsko izveštavanje o protestu na podacima prikupljenim u vodećim dnevnim i nedeljnim novinama u periodu od 24.04. do 08.05.2020. godine. Rad predstavlja doprinos novijoj literaturi o predstavljanju koja političko predstavljanje vidi kao dinamičnu i relacionu aktivnost koja se odigrava ne samo u formalnim predstavničkim institucijama, već i u civilnom društvu

Media images of the 5 October overthrow: between contestation and indifference

Poglavlje analizira medijske diskurse o Petom oktobru u poslednjih dvadeset godina. U radu se fokusiramo na tekstove objavljene povodom godišnjica Petog oktobra u dva dnevna lista, Blicu i Večernjim novostima. U analizi uočavamo tri osnovna diskursa: 1) diskurs o propuštenim šansama i izneverenim očekivanjima; 2) diskurs o (revolucionarnom?) karakteru promena, i 3) diskurs zaborava i povratka devedesetih. Nalazi takođe ukazuju na dinamiku u odnosima između stranaka starog režima i stranaka pobedničke koalicije DOS, kao i na promenu odnosa stranaka i aktera civilnog društva bez kojih Peti oktobar nije bio moguć. Poglavlje pokazuje kako jedan snažan simbol relativno brzo prelazi put od „zvezde vodilje” do simbola izneverenih očekivanja i davnoprošlog vremena, ali i postaje „prazni označitelj”.This chapter explores the media discourses about the 5 October Over- throw in Serbia in the last twenty years. We focus on the articles published in relation to the 5 October commemoration dates in two daily newspapers Blic and Večernje novosti. in the analysis, we observe three main discourses: 1) a discourse on missed opportunities and betrayed expectations; 2) discourse on the (revolutionary?) character of the changes; and 3) the discourse of indifference and the return of the 1990s. The findings also point to the dynamics in the relations between the parties of the old regime and the parties of the winning DOS coalition, as well as the change in relations between parties and civil society actors without which the 5 October would not have been possible. The chapter demonstrates how a strong symbol may easily shift from the “leading star” to the symbol of betrayed expectations and the past, but also become an “empty signifier”

Quality perception and willingness to pay: The case of red wine with health-beneficial effects

This paper attempts to identify consumers' preferences toward red wine quality cues and willingness to pay (WTP) for wine with health-beneficial effects, thus clarifying the complex process of purchasing habits and patterns. The data were analyzed using structural equation modeling. The findings from a case study conducted in Serbia show that consumer health-effect consciousness and household income are significant predictors of their WTP. On the other hand, health-conscious consumers are more inclined to intrinsic quality cues, while those who are willing to pay a higher price for a bottle of red wine are prone to extrinsic wine quality cues

Quality perception and willingness to pay: The case of red wine with health-beneficial effects

This paper attempts to identify consumers' preferences toward red wine quality cues and willingness to pay (WTP) for wine with health-beneficial effects, thus clarifying the complex process of purchasing habits and patterns. The data were analyzed using structural equation modeling. The findings from a case study conducted in Serbia show that consumer health-effect consciousness and household income are significant predictors of their WTP. On the other hand, health-conscious consumers are more inclined to intrinsic quality cues, while those who are willing to pay a higher price for a bottle of red wine are prone to extrinsic wine quality cues

Antioksidativni učinak fenolnih tvari u ekstraktima pitomog kestena (Castanea sativa Mill.)

Using electron paramagnetic resonance (EPR) spectroscopy, antioxidant properties of chestnut extracts have been investigated as a source of phenolic compounds. In addition to their high antioxidant activities against hydroxyl and organic free (DPPH) radicals, phenolics showed to be potent protectors of membranes from lipid peroxidation. To the best of our knowledge, the ability of an antioxidant to overcome body’s refractory response towards antioxidant supplementation has been examined for the first time. The water soluble extracts obtained from leaves, catkins, and outer brown peel of Castanea sativa Mill. showed high antioxidant activity in scavenging ·OH and DPPH radical. All extracts, except for sweet chestnut catkins, showed the ability to protect liposomes from peroxidation. Phenolic compounds, as active antioxidants, have the ability to enter and protect cell membranes from lipid peroxidation, thus overcoming the body’s refractory response to the antioxidant supplements in the diet. It is shown that phenolics are easily accessible natural antioxidants that can be used as food supplements or for the treatment of pathophysiological conditions related to oxidative stress.Primjenom elektronske paramagnetske rezonantne spektroskopije ispitana su antioksidativna svojstva ekstrakata kestena kao izvora fenolnih spojeva. Osim velikog antioksidativnog učinka na hidroksilne i DPPH radikale, fenolne tvari imaju i sposobnost zaštite staničnih membrana od lipidne peroksidacije. Prema spoznajama autora, po prvi je put ispitana sposobnost antioksidansa da bi se nadvladao tzv. refraktorni odgovor organizma na dijetetske antioksidativne suplemente. U vodi otopljeni ekstrakti lišća, rese i vanjske smeđe kore pitomog kestena (Castanea sativa Mill) imaju veliku sposobnost uklanjanja ·OH i DPPH radikala. Svi ekstrakti, osim ekstrakta resa kestena, sposobni su zaštititi liposome od peroksidacije. Ugradnjom fenolnih spojeva, kao aktivnih antioksidansa, u lipidni dvosloj stanične membrane sprečava se lipidna peroksidacija, čime se može nadvladati tzv. refraktorni odgovor organizma pri dodavanju antioksidativnih suplemenata hrani. Može se zaključiti da su fenolni spojevi lako dostupni prirodni antioksidansi koji bi mogli poslužiti kao dodatak prehrani i sredstvo za ublažavanje posljedica oksidativnog stresa