Mechanism and kinetics of thermally activated degradation of transition metal complexes with anions of polycarboxylic acids.

U disertaciji je ispitana termička stabilnost pet kompleksa prelaznih metala (Cu, Ni i Zn) sa anjonima aromatičnih polikarboksilnih kiselina: ftalne (pht), izoftalne (ipht) i piromelitne (pyr) kiseline i različitim aminskim ligandima, kao što su etilendiamin (en), bipiridin (bipy) i 2,2'-dipiridilamin (dipya). Razmatrani kompleksi [Cu2(bipy)2(pht)2]·4H2O, Na2[Cu(pht)2]·2H2O, K2[Cu(pht)2]·2H2O, [Zn(dipya)(ipht)]n i [Ni2(en)2(H2O)6(pyr)]·4H2O sintetisani su reakcijom izmene liganada. Strukture kompleksa detaljno su opisane zajedno sa uporednom analizom strukturnih karakteristika. Posebna pažnja posvećena je načinu koordinacije odgovarajućeg polikarboksilato-jona i konformaciji karboksilat-grupa koji uslovljavaju različitu dimenzionalnost (0 – 2D) ispitivanih materijala...Thermal stability of five transition metal (Cu, Ni and Zn) complexes containing the anions of aromatic polycarboxylic acids: phthalic (pht), isophthalic (ipht) and pyromellitic acid (pyr), and different amine ligands such as ethylenediamine (en), bipyridine (bipy) and 2,2'-dipyridylamine (dipya) was investigated. The examined complexes [Cu2(bipy)2(pht)2]·4H2O, Na2[Cu(pht)2]·2H2O, K2[Cu(pht)2]·2H2O, [Zn(dipya)(ipht)]n and [Ni2(en)2(H2O)6(pyr)]·4H2O were synthesized by ligand exchange reaction. Structures of the complexes are described in detail together with a comparative analysis of structural characteristics. Special attention has been devoted to the coordination mode of the corresponding polycarboxylato ion and the conformation of the carboxylate groups which cause the different dimensionality (0 – 2D) of the investigated materials..

Uticaj termičke obrade plodova paradajza na antioksidativnu aktivnost, sadržaj vitamina E, suve materije i ukupnih šećera

The objective of this study was the determination of total antioxidant activity, contents of vitamin E, sugar and total dry matter in fresh and thermally processed (dried and juiced) tomato fruits of different selected tomato lines with the aim to establish the nutritive profile and distinguish superior genotypes in order to obtain high-quality final product with more benefit to human health. Content of vitamin E, total antioxidant activity, dry matter and total sugars, in fresh and dried fruits (dried in parallel hot air dryer at 60 °C, until the final product reached the moisture lower than 10% and in tomato juice pasteurized at 100 °C, for 7 minutes) was studied. Comparative trial with 7 genotypes: one commercial variety (SP-109) and 6 selected high inbreeding generation lines (SPP, SPSM, SPRZ, SPRM-20, S-60 and SPO), was set up. Genotype SPRZ had the highest vitamin E content and total antioxidant capacity, both in fresh fruit and after the treatments. Thermal processing by drying at 60°C and pasteurization of tomato changed the level of total sugar and dry matter content. Total antioxidant activity decreased by drying, comparing to fresh fruit while the level of vitamin E decreased in juice pasteurized at high temperature (100 °C). .Cilj istraživanja je određivanje ukupne antioksidativne aktivnosti, sadržaja vitamina E, sadržaja šećera i ukupne suve materije u svežim i termički obrađenim (sušeni plodovi i sok) plodovima različitih selekcionih linija paradajza, sa ciljem utvrđivanja nutritivnog kvaliteta i izdvajanja superiornih genotipova, čijom preradom bi se dobio kvalitetniji krajnji proizvod sa pozitivnim dejstvom na ljudsko zdravlje. Ispitivani su sadržaj vitamina E, ukupna antioksidativna aktivnost, suva materija, i ukupni sadržaj šećera, kod svežih plodova, sušenih plodova (sušenje toplim vazduhom na 60 °C, do konačne vlage uzorka manje od 10%) i soka paradajza (pasterizacijom na 100 °C, u trajanju od 7 minuta). Izveden je komparativni ogled sa 7 genotipova, jedna komercijalna sorta (SP-109) i 6 selekcionisanih linija (SPP, SPSM, SPRZ, SPRM-20, S-60 I SPO) visokih generacija inbridinga. Termička obrada plodova paradajza (sušenjem na 60 °C) i pravljenjem soka dovodi do promene ukupnog sadržaja šećera i sadržaja ukupne suve materije. Ispitivanjem ukupne antioksidativne aktivnosti utvrđeno je da se ona gubi sušenjem u odnosu na svež plod, a sadržaj vitamina E se smanjio u soku koji je dobijen obradom na višim temperaturama (100 °C). Genotip SPRZ imao je najviše vrednosti za sadržaj vitamina E i ukupan antioksidativni kapacitet kako u svežem stanju tako i nakon primenjene obrade. Izborom superiornih genotipova i akumulacijom nutrijenata kroz oplemenjivačke programe, može se poboljšati kvalitet krajnjeg proizvoda i postići dobijanje prerađevina sa većim pozitivnim uticajem na zdravlje ljudi

Comparison of a tailings material and a natural sand in seismic site response analyses

This article investigates the seismic response of a tailings sand material in the context of site response analysis. The computed response is contrasted with that obtained for an equivalent deposit consisting of a well-characterised natural sand. Initially, the fundamental properties of both materials are used to interpret and compare their behaviour in the framework of Critical State Soil Mechanics (CSSM). Subsequently, both materials' monotonic and cyclic responses are calibrated for an advanced bounding surface plasticity model. Finally, the impact of different calibration approaches is examined through site response analyses under a strong motion. This process identifies fundamental differences between the two geo-materials, impacting the single elements simulations, especially the accuracy of undrained cyclic triaxial tests. The site response analyses examined herein show the impact of the calibrations adopted for both materials in terms of acceleration response spectra, displacements, and excess of pore water pressures (PWP). Although a relatively deep phreatic surface is adopted, the cyclic resistance and permeability of both materials plays a dominant role in the site response characteristics, controlling the excess PWP generation and hence the non-linear behaviour in the soil deposit. Finally, parametric studies are also conducted to explore the impact of permeability of the sands in the site response

Effect of nitrogen salts on the growth of Ceratonia siliqua L. Shoot cultures

Effects of reduced nitrogen salt nutriton on the growth, lenticel hypertrophy and anthocyanin accumulation of carob (Ceratonia siliqua L.) shoot cultures were investigated in conditions of light and darkness. Growth of shoot cultures was not significantly affected until nitrogen salts were reduced to less than ¼ of full-strength MS (Murashige and Skoog, 1962) values. Cultures in darkness were less affected and their main shoots even increased in length. Appearance of hypertrophied lenticels in light decreased, while in darkness they were absent in all treatments. Reduced nitrogen salt nutrition strongly affected anthocyanin accumulation of shoots and leaves, which greatly increased in both light and darkness. .Kod kultura izdanaka rogača ispitivani su efekti smanjenja koncentracije azotnih soli u podlozi MS mineralnog rastvora na multiplikaciju i izduživanje izdanaka, hipertrofiju lenticela i sintezu i akumulaciju antocijanina na svetlosti i u mraku. Smanjenje koncentracije N u podlozi bitno menja parametre rastenja izdanaka (multiplikaciju i izduživanje) tek na ¼ (na svetlosti) tj. 1/10 (u mraku). Hipertrofirane lenticele se ne razvijaju na etioliranim izdancima gajenim u mraku dok su kod izdanaka gajenim na svetlosti brojne. Smanjenjem koncentracije N u podlozi broj HL se smanjuje kao i njihovo akropetalno prostiranje. Sinteza i akumulacija antocijanina u izdancima i listovima rogača bila je direktno zavisna od koncentracije N u podlozi i na svetlosti i u mraku. .nul

The change of phytochemical profile in beet juice and the influence of different storage conditions during one year

Many scientific researches proved the antioxidative impact of beet and its products. The use of vegetable juices is getting more popular in human diet. The way of storage plays an important role in preservation, long life and minimal variability of phytonutrients. The storage of products, usually in inappropriate conditions, leads to additional loss of phytonutrients, which have already been decreased by processing. In this research, we studied the impact of three ways of storage of pasteurised beet juice during one year, on content of some nutrients (total sugars, vitamin C, phenols and total antioxidative capacity). Pasteurised juice was stored in three ways: in light, at room temperature, in dark, at room temperature and in dark, at temperature of 4 °C. The change of content and differences have been followed during one month and confirmed with ANOVA and Tukey's test. The lowest changes of total sugars have been recorded in storage in dark at 4 °C, while in storage in light, the sugar content increased. The losses of vitamin C during one year of storage had linear trend of decrease. Antioxidative capacity of beet juice depends on concentration of phenol compounds and loss of these parameters was similar during period of one year. The best way of storage was dark place at low temperature

In vitro shoot regeneration from seedling explants in Brassica vegetables: Red cabbage, broccoli, Savoy cabbage and cauliflower

Brassica oleracea varieties (red cabbage, broccoli, Savoy cabbage and cauliflower) were tested for their ability to regenerate shoots in vitro. Cotyledon, hypocotyl and root explants of 7 day-old seedlings were incubated on Murashige and Skoog's (MS) medium supplemented with 1 mg l-1 6-benzyladenine (BA) or 6-furfurylaminopurine (KIN) in combination with 0, 0.1, and 0.2 mg l-1 indole-3-butyric acid (IBA). Hypocotyls showed the best explants in almost all varieties tested with a minimum regeneration potential of 75% and producing 3.5-7.4 shoots per explant. The BA-supplemented media were optimal for both shoot regeneration and multiplication. Shoots rooted maximally (100%) on plant growth regulator-free MS medium containing 2% or 4% sucrose. Increased sucrose content improved plant acclimation in the greenhouse.Ispitivana je sposobnost četiri varijeteta Brassica oleracea (crveni kupus, brokoli, kelj i karfiol) da regenerišu pupoljke in vitro. Eksplantati kotiledona, hipokotila i korenova, uzetih sa 7 dana starih klijanaca, su gajeni na Murashige i Skoog (MS) hranljivoj podlozi sa dodatkom 1 mg l-1 6-benziladenina (BA) ili 6- furfurilaminopurina (KIN) u kombinaciji sa 0, 0.1, i 0.2 mg l-1 indol-3-butirične kiseline (IBA). Eksplantati hipokotila su se pokazali kao najbolji za regeneraciju kod skoro svih testiranih varijeteta sa minimalnim regenerativnim potencijalom od 75% i sa produkcijom 3.5- 7.4 pupoljaka po eksplantatu. Podloge koje su sadržale BA su bile optimalne, kako za regeneraiju pupoljaka, tako i za njihovu kasniju multiplikaciju. Maksimalan procenat oživljavanja izdanaka (100%) je postignut na MS medijumu bez dodatih regulatora rastenja, a koji je sadržao 2% ili 4% saharozu. Povećan sadržaj saharoze u medijumu za ožiljavanje uticao je na poboljšanu aklimatizaciju biljaka u stakleniku.Projekat ministarstva br. 143026 i TR-20072

Reduction in Pathogenic Biofilms by the Photoactive Composite of Bacterial Cellulose and Nanochitosan Dots under Blue and Green Light

In this study, nanochitosan dots (ChiDs) were synthesized using gamma rays and encapsulated in bacterial cellulose (BC) polymer matrix for antibiofilm potential in photodynamic therapy. The composites were analyzed for structural changes using SEM, AFM, FTIR, XRD, EPR, and porosity measurements. Additionally, ChiD release was assessed. The results showed that the chemical composition remained unaltered, but ChiD agglomerates embedded in BC changed shape (1.5–2.5 µm). Bacterial cellulose fibers became deformed and interconnected, with increased surface roughness and porosity and decreased crystallinity. No singlet oxygen formation was observed, and the total amount of released ChiD was up to 16.10%. Antibiofilm activity was higher under green light, with reductions ranging from 48 to 57% under blue light and 78 to 85% under green light. Methicillin-resistant Staphylococcus aureus was the most sensitive strain. The new photoactive composite hydrogels show promising potential for combating biofilm-related infections

Nano breathers and molecular dynamics simulations in hydrogen-bonded chains

Non-linear localization phenomena in biological lattices have attracted a steadily growing interest and their existence has been predicted in a wide range of physical settings. We investigate the non-linear proton dynamics of a hydrogen-bonded chain in a semi-classical limit using the coherent state method combined with a Holstein-Primakoff bosonic representation. We demonstrate that even a weak inherent discreteness in the hydrogen-bonded (HB) chain may drastically modify the dynamics of the non-linear system, leading to instabilities that have no analog in the continuum limit. We suggest a possible localization mechanism of polarization oscillations of protons in a hydrogen-bonded chain through modulational instability analysis. This mechanism arises due to the neighboring proton-proton interaction and coherent tunneling of protons along hydrogen bonds and/or around heavy atoms. We present a detailed analysis of modulational instability, and highlight the role of the interaction strength of neighboring protons in the process of bioenergy localization. We perform molecular dynamics simulations and demonstrate the existence of nanoscale discrete breather (DB) modes in the hydrogen-bonded chain. These highly localized and long-lived non-linear breather modes may play a functional role in targeted energy transfer in biological systems