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Electrospun poly(ε-caprolactone) nanofiber mats with gallic acid and glucosamine sulfate for cartilage repair
No full textCartilage defects are a common clinical problem, and tissue engineering has become a promising
approach for cartilage regeneration because of its high efficiency [1]. The goal of this research was the development of
poly(ε-caprolactone) (PCL) nanofiber mats with incorporated active substances gallic acid (GA) and glucosamine sulfate
(GAS) as an unexplored alternative for cartilage repairExcellMater Conference 2024: Innovative Biomaterials for Novel Medical Devices, Belgrade, Serbia, April 10-12, 202
Cavitation erosion of samples based on cordierite-talc ceramics
No full textIn the paper, the cavitation resistance of cordierite samples with the addition of 10%, 15% and 20% talc, sintered at 1200⁰ C, was investigated. The ultrasonic vibration method with a stationary sample according to the ASTM G32 standard was applied. The formation and development of damage to the surface of the samples was monitored using a scanning electron microscope and the level of damage to the surface of the samples was quantified using image analysis. The change in the mass of the samples as a function of the cavitation time was monitored to determine the cavitation rate. By measuring the mass loss and morphological analysis of the pits formed on the surface of the sintered samples of the cordierite-talc ceramics, the mechanism of degradation and resistance to the effect of cavitation was monitored. The obtained results were compared with the results of earlier tests of cavitation resistance of sintered cordierite samples. The addition of talc in the mixture with cordierite significantly improved cavitation resistance of the sintered material compared to sintered pure cordierite. The tests were done to see the potential application of this material in hydrodynamic conditions, especially because of the strong corrosion resistance of these refractory materials
Mechanical properties of immersed Kevlar/PVB composites with ZnO nanoparticles
No full textThe Kevlar fabric composites are widely applied for body armor and vehicle armor structures.
In this study, the specimens were produced of the Kevlar fabrics impregnated with
10 wt.% poly (vinyl butyral)/ethanol solution which contained the ZnO nanoparticles in
different concentrations (1 wt.% or 2 wt.% in relation to poly (vinyl butyral), PVB). The
two-layered Kevlar/PVB composite samples were fabricated by hot compression.
In accordance with the ISO 62 standard, the square Kevlar/PVB composite specimens were
immersed for the water uptake measurements. The tensile and flexural properties of the
Kevlar/PVB specimens were examined in compliance with the ASTM D 3039 and ASTM D
790-03 standards, respectively. The specimens that had been submerged in distilled water
at 40 ◦C for eight weeks were compared to the dry specimens in terms of their tensile and
bending characteristics.
The addition of ZnO nanoparticles significantly improved the tensile strength and tensile
modulus of the dry Kevlar/PVB specimens. In contrast to the tensile test results, the dry
specimens with no nanoparticles exhibited the superior flexural qualities (strength and modulus)
because of the better bonding between their two impregnated fabric layers.
When compared to their dry counterparts, the tensile and bending properties of every immersed
Kevlar/PVB composite specimen showed some lower values
Novel diphenyltin(IV) complexes with carboxylato N-functionalized 2-quinolone ligands: Synthesis, characterization and in vitro anticancer studies
No full textThree new diphenyltin(IV) complexes, bis(3-(4-methyl-2-oxoquinolinyl-1(2H)-yl)propanoato)diphenyltin(IV)
(1), bis(2-(4-methyl-2-oxoquinolin-1(2H)-yl)ethanoato)diphenyltin(IV) (2), and bis(2-(4-hydroxy-2-oxoquinolin1(2H)-yl)ethanoato)diphenyltin(IV) (3), were synthesized and characterized by elemental microanalysis, FT-IR
spectroscopy, and multinuclear (
1
H, 13C and 119Sn) NMR spectroscopy. Crystal structure of ligand precursor,
2-(4-methyl-2-oxoquinolinyl-1-(2H)-yl)acetic acid (HL2), has been determined by X-ray diffraction studies.
Asymmetric bidentate coordination of the carboxylato ligands and skew trapezoidal structures are assumed for
the synthesized complexes. In vitro anticancer activity of the synthesized diphenyltin(IV) complexes was evaluated against three human: MCF-7 (breast adenocarcinoma), A375 (melanoma), HCT116 (colorectal carcinoma),
and three mouse tumor cell lines: 4T1 (breast carcinoma), B16 (melanoma), CT26 (colon carcinoma) using MTT
and CV assays. The IC50 values fall in the range from 0.1 to 3.7 μM. Flow cytometric analysis and fluorescent
microscopy suggest that complex 1 induces caspase-dependent apoptosis followed with strong blockade of cell
division in HCT116 cells. Since complex 1 showed ROS/RNS scavenging potential mentioned cytotoxicity was
not connected with oxidative stress
Black cumin essential oil as a valuable source of bioactive compounds: Evaluation of the conventional vs. modern extraction technique
No full textWithin this investigation, the effect of conventional and sophisticated extraction method was evaluated on the chemical composition of black cumin seeds (Nigella sativa L.) essential oils and their bioactive characteristics. Soxhlet extraction at 60 °C by hexane (SEH) and petroleum ether (SEP) was adopted as traditionally used technique, while the supercritical extraction with CO2 (SFE), under the pressure of 10 MPa and temperature of 40 °C, was performed as a modern method, expected to overcome the drawbacks of the conventional solvent extraction. The results showed that SFE enabled up to ten times higher extraction yields, compared to essential oils derived after Soxhlet extraction, however, the bioactive compounds content, such as polyphenols, flavonoids and carotenoids, were extracted in higher quantities in the oil from Soxhlet extraction performance. Thereby, the strongest antioxidant agent was found to be the essential oil obtained from SEP, followed by the oil from SFE and oil obtained from SEH, respectively. The GC-MS analysis revealed that the content of thymoquinone was the highest in the essential oil from SEP (69.58%), and the obtained values are among the highest reported within the available literature data. Also, this oil sample contained about eleven times higher thymoquinone quantities than the essential oil obtained by SFE, which was mostly constituted of a methyl linoleate, a fatty acid methyl ester of linoleic acid. In addition, the essential oil from SEP exerted a value added antimicrobial properties, where it was found to be particularly effective in suppression of the Gram-positive bacteria growth
Adsorption-desorption efficiency and reusability of modified fly ash in removing azo dyes
No full textEfikasnost modifikovanog letećeg pepela za uklanjanje azo-boja i mogućnost njegove
ponovne upotrebe utvrđeni su kroz cikluse adsorpcije i desorpcije. Adsorbenti su
okarakterisani standardnim metodama, FTIR i SEM. Ispitivanje efikasnosti adsorpcije
pokazalo je da su modifikovani materijali efikasniji u uklanjanju metilen plavog, kristalno
ljubičastog i briljantno zelenog u poređenju sa sirovim letećim pepelom. Desorpcija
metilenskog plavog sa materijala nakon adsorpcije ispitivana je korišćenjem različitih
organskih rastvarača (metanol, etanol, etil-acetat), pri čemu je etanol izabran kao
najefikasniji. Ponovna upotreba modifikovanog letećeg pepela ispitana je u tri ciklusa
procesa adsorpcije i desorpcije. Utvrđeno je da se termički modifikovana smeša letećeg
pepela i NaOH može koristiti kao efikasan adsorbent za uklanjanje odabranih azo-boja.The efficiency of modified fly ash for the removal of azo dyes and its reuse cycles were determined through adsorption-desorption tests. The adsorbents were characterized using standard methods, FTIR, and SEM. The adsorption test showed that the modified materials were more effective in removing methylene blue, crystal violet, and brilliant green compared to raw fly ash. The desorption of methylene blue from the material was investigated using different organic solvents (methanol, ethanol, ethyl acetate), with ethanol being the most effective. The reuse of modified fly ash was investigated over three cycles of adsorption and desorption processes. It was found that a thermally modified mixture of fly ash and NaOH can be used as an effective adsorbent for the removal of selected azo dyes
Correction to: The influence of exploration activities of a potential lithium mine to the environment in Western Serbia (Scientific Reports, (2024), 14, 1, (17090), 10.1038/s41598-024-68072-9)
No full textCorrection to: Scientific Reportshttps://doi.org/10.1038/s41598-024-68072-9, published online 24 July 2024 The original version of this Article contained errors. Original Ref 10 was not appropriate reference to support the statement where it was cited. It is therefore now replaced by a new Ref 10, and new Ref 11 and 12 are further added to support this statement. As a result, in the Introduction, “The easiest and least environmentally damaging method of exploiting lithium is from brines, while exploitation from ore rocks has severe environmental consequences10.” now reads: “The easiest and least environmentally damaging method of exploiting lithium is from brines, while exploitation from ore rocks has severe environmental consequences10,11, 12.” and in References, “10. Liu, W., Agusdinata, D. B. & Myint, S. W. Spatiotemporal patterns of lithium mining and environmental degradation in the Atacama Salt Flat, Chile. Int. J. Appl. Earth Obs. Geoinf. 80, 145–156 (2019).” now reads: “10. Songyan Jiang, Ling Zhang, Fengying Li, Hui Hua, Xin Liu, Zengwei Yuan, Huijun Wu, Environmental impacts of lithium production showing the importance of primary data of upstream process in life-cycle assessment. Journal of Environmental Management 262 (2020) 110253. https://doi.org/10.1016/j.jenvman.2020.110253” New Ref 11 and 12 are: 11. Guozeng Gu, Tianming Gao, Sustainable production of lithium salts extraction from ores in China: Cleaner production assessment. Resources Policy 74 (2021) 102261. https://doi.org/10.1016/j.resourpol.2021.102261. 12. Shayan Khakmardan, Maximilian Rolinck, Felipe Cerdas, Christoph Herrmann, Damien Giurco, Robert Crawford, Wen Li, Comparative Life Cycle Assessment of Lithium Mining, Extraction, and Refining Technologies: a Global Perspective. 30th CIRP Life Cycle Engineering Conference. Procedia CIRP 116 (2023) 606–611. https://doi.org/10.1016/j.procir.2023.02.102. All subsequent references were re-ordered accordingly. Secondly, as a result of a mix-up with data sources the special coverage of the Jadar project was incorrectly estimated. Additionally, one of the numbers was given incorrectly due to a typo. This is now corrected using original Ref 28 (now Ref 30) as a sole source of information. In ‘Ecological risk assessment of the Jadar lithium mine in Western Serbia’, “The preliminary estimated spatial coverage of the Jadar project is between 2031 and 2431 ha, with 533 ha of land expected to be destroyed during the initial phase of the project implementation. Of the land to be destroyed, 203 ha are forests, and 317 ha is arable land.” now reads: “The preliminary estimated spatial coverage of the Jadar project is 2031, with 533 ha of land expected to be destroyed during the initial phase of the project implementation. Of the land to be destroyed, 206.5 ha are forests, and 173 ha is arable land.” Additionally, original Ref 27 was incorrectly used in the same section. It was now removed – original Ref 31 (now Ref 33) cited at the end of the paragraph supports it in its entirety. As a result, in ‘Ecological risk assessment of the Jadar lithium mine in Western Serbia’, “The planned “Jadar” project is expected to cause significant habitat destruction and fragmentation, resulting in severe negative impacts on the living world, including several hundred plant and animal species. Among these species, 145 have protected and strictly protected status27. The project would also threaten the isolated eastern enclave of T. scorodonia, a sub-Atlantic species located more than 600 km away from the nearest western population. Additionally, the rare fern Dryopteris and 20 other rare species would disappear from the site of the planned tailings lands, as reported by Krizmanić et al. in 202131.” now reads: “The planned “Jadar” project is expected to cause significant habitat destruction and fragmentation, resulting in severe negative impacts on the living world, including several hundred plant and animal species. Among these species, 145 have protected and strictly protected status. The project would also threaten the isolated eastern enclave of T. scorodonia, a sub-Atlantic species located more than 600 km away from the nearest western population. Additionally, the rare fern Dryopteris and 20 other rare species would disappear from the site of the planned tailings lands, as reported by Krizmanić et al. in 202133.” Incorrect annual production tonnages were used when discussing the previous feasibility study. In ‘Eco‑chemical risk of jadarite mining and lithium extraction’, “Based on a feasibility study45, the annual production of Li2CO3 would be 50,000 t/year, and B(OH)3 production would reach 248,000 t/year.” now reads: “Based on a feasibility study47, the annual production of Li2CO3 would be 58,000 t/year, and B(OH)3 production would reach 286,000 t/year.” Additionally, in the same section, “We predict that with the mine opening, in addition to the presented problems that will multiply, new problems would arise due to pond tailings the company plans to place next to the two torrential rivers Korenita and Jadar and also in Štavica River valley uphill from the lithium boron mine and ore processing plant.“ now reads “We predict that with the mine opening, in addition to the presented problems that will multiply, new problems would arise due to tailings the company plans to place next to the two torrential rivers Korenita and Jadar and also in Štavica River valley uphill from the lithium boron mine and ore processing plant. The landfill in Štavica river would block river’s free flow and create a pond.” In ‘Socio‑environmental risks of Rio‑Tinto’s jadarite mining project in Serbia’, “During the initial stages of the proposed mining project, some residents allowed sample drilling on their properties without realizing that their land was located on the planned tailings pond.” now reads: “During the initial stages of the proposed mining project, some residents allowed sample drilling on their properties without realizing that their land was located on the planned tailings.” In original Ref 31 (now Ref 33), an initial of one of the authors was incorrect: “Anđelković, A.” in the author list now reads “Anđelković, M”. Finally, in the Supplemental Information 1, a methodological description of the sample collection and preparation, ICP-OES measurements, and calibration was also included (as a result, SI file contains new References 4–10; subsequent references were re-ordered accordingly). The original version of this Article and the associated supplementary materials were corrected.Correction to: [https://doi.org/10.1038/s41598-024-68072-9]Correction to: [https://technorep.tmf.bg.ac.rs/handle/123456789/7580
Microwave Irradiation as a Powerful Tool for Isolating Isoflavones from Soybean Flour
No full textThe use of microwave irradiation energy for isolating bioactive compounds from plantmaterials has gained popularity due to its ability to penetrate cells and facilitate extraction ofintracellular materials, with the added benefits of minimal or no use of organic solvents. Thisis particularly significant due to the possibility of using extracts in the food and pharmaceuticalindustries. The aim of this work is to examine the effect of microwave irradiation on the extraction ofthree of the most important isoflavones from soybean flour, glycitin, genistin, and daidzin, as well astheir aglycones, glycitein, genistein, and daidzein. By varying the extraction time, temperature, andmicrowave power, we have established the optimal parameters (irradiation power of 75 W for 5 min)for the most efficient extraction of individual isoflavones. Compared to conventional macerationand ultrasound-assisted extraction, the total phenol content of the extracts increased from 3.66 to9.16 mg GAE/g dw and from 4.67 to 9.16 mg GAE/g dw, respectively. The total flavonoid contentincreased from 0.38 to 0.83 mg CE/g dw and from 0.48 to 0.83 mg CE/g dw, and the antioxidantactivity increased from 96.54 to 185.04 μmol TE/g dw and from 158.57 to 185.04 μmol TE/g dw, butalso from 21.97 to 37.16 μmol Fe2+/g dw and from 30.13 to 37.16 μmol Fe2+/g dw. The positivecorrelation between microwave extraction and increased levels of total phenols, flavonoids, andantioxidant activity demonstrates the method’s effectiveness in producing bioactive compounds.Considering the growing recognition of glycitein’s potential role in medical and pharmaceuticalapplications, microwave-assisted extraction under optimized conditions has proven highly efficient
Fotodegradacija tiofanat-metila pod dejstvom svetlosti koja imitira sunčevo zračenje korišćenjem novih kompozitnih fotokatalizatora
No full textThis work aimed to investigate the influence of modified titanium(IV) oxide by different nanosized particles on photocatalytic capacity to decompose the chosen organic pollutant under simulated sunlight. For that purpose, rutile-phased titanium(IV) oxide (r-TiO2) was decorated with iron vanadate (FeVO4/r-TiO2) and vanadium-substituted goethite (Fe1-xVxOOH/r-TiO2). The obtained composites were characterized by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X ray powder diffraction, Brunauer-Emmett-Teller, Fourier transform infrared spectroscopy – attenuated total reflectance and ultraviolet–visible diffuse reflectance spectroscopy techniques. Both synthesized photocatalysts showed higher photoactivity than the base r-TiO2 for the degradation of the target contaminant-thiophanate-methyl (2.5 h vs. 5 h). During the tests, parameters like the irradiation time, catalysts amount, and pesticide concentration were systematically investigated. Furthermore, photocatalysts were applied in multicycle degradation tests for examining their effectiveness during exploitation time. Monitoring of the removal rate was performed both by UV/visible spectrometry and high-performance liquid chromatography (HPLC). In order to prove completion of fungicide degradation chemical oxygen demand was measured in the course of the photocatalytic experiment. The final concentration of the observed contaminant in treated samples was under the prescribed legislative level. The fabricated materials displayed great reliability, durability and photocatalytic activity representing good potentials for implementing this process in real wastewater treatment plants. © 2024, Association of the Chemical Engineers of Serbia. All rights reserved.Ovaj rad ima za cilj da prikaže uticaj prisustva nanočestica na površini titanijum (IV) oksida na fotokatalitički kapacitet razlaganja prisutnog organskog polutanta pod dejstvom simulirane sunčeve svetlosti. U tu svrhu, površina rutil titanijum (IV) oksida (r-TiO2) dekorisana je železo vanadatom (FeVO4/r-TiO2) i vanadijumom supstituisanim getitom (Fe1-xVxOOH/r-TiO2). Dobijeni kompoziti su okarakterisani primenom skenirajuće elektronske mikroskopije u emisionom polju uz energetsku disperzionu spektroskopiju, difrakcije X-zraka na sprašenim uzorcima, adsorpcijom azota na tački ključanja primenom Brunauer-Emet-Teler metodologije, infracrvene spektroskopije sa Furijeovom transformacijom u modu smanjene totalne refleksije i spektroskopije difuzne refleksije ultraljubičastovidljivog zračenja. Oba fotokatalizatora su pokazala veću fotoaktivnost od komercijalnog r-TiO2 za degradaciju tiofanat-metila (2,5 h umesto 5 h). Tokom ispitivanja ispitivani su faktori kao što su vreme zračenja, količina katalizatora i koncentracija pesticida. Takođe, fotokatalizatori su primenjeni u uzastopnim višecikličnim testovima degradacije da bi se ispitala njihova efikasnost tokom dužeg vremena eksploatacije. Praćenje brzine uklanjanja vršeno je pomoću spektrometrije ultraljubičastog/vidljivog zračenja i tečne hromatografije visokih performansi. Pomoćni alat za proveru potpunosti razgradnje fungicida jeste određivanje hemijske potrošnje kiseonika nakon svake faze tretmana. Koncentracija posmatrane zagađujuće materije u tretiranim uzorcima je ispod propisanog zakonskog nivoa. Pripremljeni materijali su pokazali veliku stabilnost, postojanost i fotokatalitičku aktivnost što predstavlja dobru osnovu za primenu ovog procesa u realnim postrojenjima za prečišćavanje otpadnih voda
Fractal Analysis and Microstructure Development PVDF Based Multifunctional Material
No full textPolyvinylidene fluoride (PVDF) is a novel gel polymer electrolyte alternative which can reduce the risk of irreversible failure in lithium-ion batteries (LIB) [1]. PVDF matrix structures which exhibit inter-crosslinking networks have previously demonstrated favorable thermal and mechanical properties for LIB applications [2]. PVDF based multifunctional material is attracting a great scientific interest due to its excellent piezoelectric, pyroelectric and ferroelectric properties. Such as, its properties strongly depend on synthesis procedures and obtained microstructures. In this research, porous structure and cross-linking patterns of PVDF were prepared by electrospinning method and it has been found that these microstructures can have fractal structure. Fractal analysis can be used as a powerful tool for describing structural and functional properties of these this material. Because of that, in this research we have used different fractal methods for the reconstructions of various PVDF microstructure morphologies. Fractal analysis has been performed by using scanning electron microscope micrographs and computational modeling tools. Theory of Iterated Function Systems and Voronoi tessellation, have been used for modeling PVDF porous structures. A Python algorithm was created to determine the distribution of pore areas in SEM micrographs. Algorithm’s distribution of calculated pore surface areas were compared with measured pore surface areas and fractal reconstructions of different morphologies and their connection with functional properties were analyzed