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Characteristics of sea seawater battery with magnesium alloy AZ63 and a rechargeable composite positive electrode based on polypyrrole and silver chloride
No full textAqueous seawater batteries hold significant promise for different applications.
However, the instability of cathode materials limits their widespread application. This study presents the development of a new hybrid cell featuring a novel
rechargeable composite positive electrode that is prepared using the functionalized carbon felt (FCF), electrochemically synthesized polypyrrole (PPy), which is
coated with silver chloride (AgCl) by a modified successive ion layer adsorption
and reaction (SILAR) technique. The FCF/PPy–AgCl cathode demonstrated good
electrochemical and electrical characteristics. During charge, oxidizing (doping
with chloride anions) of PPy and oxidation of Ag to AgCl, while during discharge,
the dedoping of PPy and reduction of AgCl to metallic Ag occurred. Combined
with an AZ63 (aluminum-zinc) magnesium alloy that behaves as a classical primary cell anode during discharge, and a hydrogen-evolving electrode during
charge, the hybrid cell exhibited high specific power at high discharge rates.
At low discharge rates, the oxygen reduction reaction occurred, and significant
energy output can be achieved. It is estimated that under cycling with a relatively
high rate of ~1.8Q, a capacity fade of 30% occurred after ~175 charge/discharge
cycles. The possible application of the AZ63 | 3.5% NaCl | FCF/PPy–AgCl cell
for life-saving boats and as short-term power sources for monitoring shallow
seawater quality, with proposed electronic components and working algorithm,
is discussed. By utilizing seawater as a sustainable electrolyte and eco-friendly
materials, this system demonstrates a novel approach to energy storage systems
Role of Cholesterol in Modifying the Physical and Stability Properties of Liposomes and In Vitro Release of VitaminB12
No full textCholesterol has garnered significant attention in research due to its role in the
structure and the fluidity/rigidity of phospholipid membranes. This property makes it an
essential component in liposome formulation. Finding the right ratio of phospholipid-tocholesterolis important for making a liposome formulation that is stable and functional.
This study involved the investigation of various mass ratios between phospholipid and
cholesterol. The resulting formulations were characterized in terms of mean particle size,
size distribution, and ζ potential. It was observed that as the cholesterol content increased,
the mean particle size also increased, with the stability of the suspensions improving up to
a certain point, after which stability decreased. The optimal phospholipid-to-cholesterol
ratio of 5:1 was identified and chosen for subsequent studies on the encapsulation of
vitamin B12. The vitamin was encapsulated in the liposomes in the amount of 37%, and
the controlled release of vitamin B12 under gastrointestinal conditions was demonstrated
using the liposomes as a carrier.The IX International Congress “Engineering, Environment and Materials in Process Industry”—EEM2025, 2-4 April 2025, Bijeljina, Bosnia and Herzegovin
Mineral Content of Honey from Serbia: Analysis of Essential and Toxic Elements
No full textHoney is a natural, sweet, and complex substance produced by honey bees from nectar collected from various plants. After processing, nectar is stored in wax honeycombs, forming honey, which contains several hundred chemical compounds responsible for its diverse biological activities. Traditionally consumed as a nutritious food, honey also exhibits antimicrobial, antioxidant, anti-inflammatory, immunomodulatory, antitumor, and probiotic effects, making it significant for both nutritional and therapeutic purposes. In this study, the mineral composition of honey was analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES) to determine the concentrations of micro- and macroelements, some of which are essential for human health, while others are potentially toxic even at low levels. More than 20 elements were quantified, including Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Ni, P, Pb, S, Se, Sr, and Zn. Six honey samples from different geographical regions available on the Serbian market were examined: three domestic samples collected from small family farms and three purchased from retail outlets. Due to the complex honey matrix, sample preparation involved dry digestion with mineral acids to enable efficient metal extraction. Cluster analysis was applied to investigate the relationship between the elemental composition and the geographical origin of honey, providing insights into honey quality, authenticity, and potential health risks associated with toxic element content
Optimization of Milling Process Parameters for Waste Plum Stones for Their Sustainable Application
No full textThe impact of milling process parameters on the physicochemical properties of waste plum stones was investigated to enable their further utilization as a functional material. The experiments were conducted using a planetary ball mill, with variations in milling duration (1–3 h), the ball-to-powder ratio (bpr) (10:1 and 20:1), and the rotation speed (250 and 500 rpm). Transformations of material in a function of process parameters were assessed by XRD, FTIR, and SEM analysis, revealing differences in particle size distribution, functional group composition, and surface morphology. Optimization of milling process parameters was focused on promoting fine particle formation and surface activation without causing significant material degradation. The best result was achieved with the PS-M10 sample, processed at a speed of 500 rpm and a bpr of 20:1 during a short milling time of 1 h. The milled sample demonstrated promising potential for further applications, particularly for heavy metal ion (Pb2+ and Cu2+) removal from aqueous solutions through adsorption
Radical Scavenging Activity of Silymarin Encapsulated in Liposomal Vesicles: Impact of UV Irradiation and Lyophilization
No full textThe radical scavenging activity of silymarin-loaded liposomes after different technological processes (UV irradiation and lyophilization) was investigated using DPPH and ABTS assays. Using the DPPH method, the antioxidant capacity of pure silymarin was 84.03%, while it was lower after encapsulation in liposomes; it was 81.63% after the formulation, 81.15% after UV irradiation, and 79.85% after lyophilization. The anti-ABTS potential was 3.04 µmol Trolox equivalent (TE)/mL for silymarin, 1.68 µmol TE/mL after the liposome preparation, 1.52 µmol TE/mL after UV irradiation, and 2.02 µmol TE/mL after lyophilization. UV irradiation did not cause significant changes in the antioxidant potential of liposomes, while the ABTS scavenging activity was higher after lyophilization. Considering that the two used antioxidant assays are based on different reactions, the obtained data provide a good insight into the overall antioxidant activity of silymarin-loaded liposomes.The IX International Congress “Engineering, Environment and Materials in Process Industry”—EEM2025, 2-4 April 2025, Bijeljina, Bosnia and Herzegovin
Modularni alat za izradu hladnjaka postupkom zavarivanja trenjem alatom
No full textPrikazani pronalazak, modularni alat za izradu hladnjaka postupkom zavarivanja trenjem alatom kao predmetom pronalaska, odnosi se na konstrukciono rešenje alata za proizvodnju neprekidnog tunela unutar ploče od aluminijuma primenom postupka zavarivanja trenjem alatom. Modularni alat se sastoji od međusobno spojenih trna (17) alata, tela (10) alata sa čelom (3), dva aksijalno radijalna ležaja (11,13), čaure (12) i sigurnosnog prstena (15). Trna alata (17) se sastoji od čvrsto spojenih gornjeg dela (16) trna alata za stezanje u mašini i nošenje tela alata (10)s a čelom (3) i donjeg dela (9) trna alata koji na svom slobodnom kraju poseduje desnu zavojnicu (4) iznad koje je u njemu izveden žleb (5). U donjem delu tela (10) alata su izvedeni jedan prolazni aksijalni otvor za prihvat donjeg dela (9) trna alata i dva radijana otvora (2,8,) u čijoj neposrednoj blizini se nalazi čelo (3) tela (10) alata. Čelo (3) tela (10) alata svojim pritiskom na gornju površinu (1) radne ploče (6) obezbeđuje ravnu i glatku površinu zavarenog spoja i kvalitetan zavareni spoj iznad obrazovanog tunela (7), što je uslov za proizvodnju ispravnih hladnjaka bez curenja.Broj prijave: MP-2025/0013Broj i datum rešenja o priznanju prava: 2025/4262 26.05.202
Exposure and Toxicity Factors in Health Risk Assessment of Heavy Metal(loid)s in Water
No full textHeavy metal(loid) (HM) contamination in water arises from various anthropogenic activities and natural processes, posing risks to human health through ingestion and dermal absorption. Although numerous studies have assessed health risks associated with HMs in water, inconsistencies in the selection of exposure and toxicity factors limit comparability and reliability across studies. To address this gap, the aim of this review was to provide a comprehensive synthesis of exposure and toxicity factors used in health risk assessment (HRA) of HMs in water. The objectives were to evaluate the variability in ingestion, body weight, exposure duration and frequency, and dermal contact parameters, as well as in reference doses and cancer slope factors and to propose standardized values and statistical distributions for more consistent risk estimation. A systematic search of the Scopus database retrieved 806 studies, from which highly cited articles (≥100 citations) and recent publications (2023–2025) were prioritized for analysis. The findings revealed substantial variability in factors and showed that probabilistic approaches, particularly Monte Carlo simulation, were increasingly applied and provided more reliable estimates than traditional deterministic methods. The highest agreement was observed for exposure frequency for ingestion (365 days/year) and skin surface area (18,000 cm2), each applied in 75.5% of cases. By identifying inconsistencies in current practices and proposing standardized exposure and toxicity values and distributions for water, this review is expected to offer practical recommendations to improve the robustness, reliability, and comparability of HRAs, ultimately informing more effective policy-making and water management practices
Optical, Structural, and Biological Characteristics of Rapid-Sintered Multichromatic Zirconia
No full textTo overcome the esthetic limitations of dental monolithic zirconia restorations, multichromatic systems were developed to combine improved structural integrity with a natural shade gradient that mimics the optical properties of natural teeth. In response to the clinical demand for time-efficient, i.e., chairside fabrication of zirconia restorations, rapid sintering protocols have become necessary to adjust clinical efficiency along with material performance. This study addresses the challenges of a rapid sintering protocol related to optical performance and phase transformation of the final restoration and the zirconia–cell interaction. Methods: The influence of a rapid sintering protocol on the color stability of the final dental restoration was evaluated by the CIE L*a*b* color space. Phase transformation was assessed through X-ray diffraction analysis. Cellular behavior was evaluated by measuring wettability, the material’s surface energy, and a cell mitochondrial activity assay on human gingival fibroblasts. Results: Optical measurements demonstrated that the total color change in all layers after rapid sintering was above the perceptibility threshold (ΔE* > 1.2), while only the polished enamel layer (ΔE* = 3.01) exceeded the acceptability threshold (ΔE* > 2.7), resulting in a clinically perceptible mismatch. Results of X-ray diffraction analysis, performed for fixed occupancy at Z0.935Y0.065O0.984, revealed that rapid sintering caused a decrease in the cubic (C-) phase and an increase in the total amount of tetragonal (T-) phases. Conventionally sintered zirconia consists of 54% tetragonal (T-) and 46% cubic (C-) phase, whereas in the speed-sintered specimens, an additional T1 phase was detected (T = 49%; T1 = 27%), along with a reduced cubic fraction (C = 24%). Additionally, a small amount of the monoclinic (M) phase is noticed. Although glazing as a surface finishing procedure resulted in increased hydrophilicity, both polished and glazed surface-treated specimens showed statistically comparable cell adhesion and proliferation (p > 0.05). Conclusions: Rapid sintering induced perceptible color changes only in the enamel layer of multichromatic zirconia, suggesting that even layer-specific alterations may have an impact on the overall esthetic outcome of the final prosthetic restoration. Five times higher heating and cooling rates caused difficulty in reaching equilibrium, leading to changes in lattice parameters and the formation of the metastable T1 phase
Valorizacija sporednih proizvoda industrije čaja koprive kroz inovativnu zelenu ekstrakciju i fermentaciju za primenu u funkcionalној hrani
No full textRazličiti sektori prehrambene industrije stvaraju značajnu količinu otpada , što predstavlja ozbiljan problem ako se njime ne upravlja na pravi način. Nusproizvodi industrije biljnog čaja koji ostaju nakon sušenja i sečenja bogati su bioaktivnim jedinjenjima kao što su polifenoli, flavonoidi, fenolne kiseline itd., međutim, nedovoljno iskorišćeni. Otprilike 10–40% (u zavisnosti od biljne vrste) ukupne prerađene sirovine u proizvodnji biljnog filter čaja su nusproizvodi u obliku pulvisa. Kopriva (Urtica dioica) je važan deo ljudske ishrane i najčešće se koristi za lečenje hiperplazije prostate, hiperglikemije, alergija, anemije itd., zbog svog raznovrsnog hemijskog profila. Pošto je kopriva bogata polifenolima uključujući flavonoide i fenolne kiseline, vitamine, minerale itd., očekuje se da može biti dobar supstrat za biotransformaciju bakterija mlečne kiseline. Optimizovana prerada, uključujući ekstrakciju i biotransformaciju, može pretvoriti ove nusproizvode u vredne izvore biološki aktivnih jedinjenja za funkcionalnu primenu u hrani. Ova studija upoređuje inovativne metode valorizacije nusproizvoda koprive u skladu sa principima kružne bioekonomije. Zelene tehnike, uključujući ultrazvučnu i ekstrakciju uz pomoć netermalne plazme, korišćene su za efikasan oporavak bioaktivnih jedinjenja iz nusproizvoda koprive.
Upoređeni su i proučavani tretmani i rastvarači (mešavine voda i voda/etanol) kako bi se ispitala njihova selektivnost prema antioksidativnim jedinjenjima koja su pogodni kao supstrati za biotransformacije. Ekstrakti su korišćeni kao supstrati za rast Ligilactibacillus salivarius ATCC 11741, soja bakterija mlečne kiseline sa probiotičkim potencijalom. Ekstrakti su liofilizovani i kasnije rekonstituisani vodom, da bi se dobio medijum na bazi vode za rast L. salivarius. Procenjivane su antioksidativne aktivnosti, ABTS, DPPH i ukupni fenolni sadržaj, kao i rast L. salivarius. Dalje, biotransformacija vodenih ekstrakata fermentacijom sa L. salivarius je potvrđena HPLC analizom. Fermentacija je poboljšala kvalitet ekstrakta povećanjem koncentracije fenolnih jedinjenja, i to kofeinske kiseline (44%), hlorogenske kiseline (35%) i derivata kafeinske kiseline (44%), uz održavanje visoke stope rasta ispitivanog mikroorganizma. DPPH test je pokazao visoku aktivnost od 234 trolok ek/g dm u fermentisani ekstraktima ekstrahovani termalnom plazmom. Iako se netermalna plazma u nekim slučajevima koristi u antimikrobne svrhe, L. salivarius je pokazao visoki rast i u ekstraktima exstrahovanim netermalnom plazmom i u ekstraktima estrahovanim uz asistenciju ultrazvukom. Fermentacija sa L. salivarius bila je direktno povezana sa povećanjem koncentracije biološki aktivnih jedinjenja, što otvara nove mogućnosti za biotransformaciju ekstrakata, potencijalno i sa drugim bakterijama mlečne kiseline za dobijanje novih specifičnih proizvoda fermentacije.
Fermentisani vodeni ekstrakti su pokazali značajan potencijal kao simbiotici sa antioksidativnim i postbiotičkim svojstvima. Stabilnost fermentisanih ekstrakata treba dalje ispitati kako bi se predložio najbolji put za njihovu eksploataciju, ali povećana biološka aktivnost sugeriše da bi njihova primena mogla da se proteže od funkcionalne hrane do dijetetskih suplemenata i kozmetičkih sastojaka.Različiti sektori prehrambene industrije stvaraju značajnu količinu otpada, što predstavlja ozbiljan problem ako
se njime ne upravlja na pravi način. Sporedni proizvodi industrije biljnog čaja koji ostaju nakon sušenja i sečenja
bogati su bioaktivnim jedinjenjima kao što su polifenoli, flavonoidi, fenolne kiseline itd., međutim, nedovoljno
iskorišćeni. Otprilike 10–40% (u zavisnosti od biljne vrste) ukupne prerađene sirovine u proizvodnji biljnog
filter čaja su sporedni proizvodi u obliku pulvisa. Kopriva (Urtica dioica) je važan deo ljudske ishrane i najčešće
se koristi za lečenje hiperplazije prostate, hiperglikemije, alergija, anemije itd., zbog svog raznovrsnog
hemijskog profila. Pošto je kopriva bogata polifenolima uključujući flavonoide i fenolne kiseline, vitamine,
minerale itd., očekuje se da može biti dobar supstrat za biotransformaciju bakterija mlečne kiseline.
Optimizovana prerada, uključujući ekstrakciju i biotransformaciju, može pretvoriti ove nusproizvode u vredne
izvore biološki aktivnih jedinjenja za funkcionalnu primenu u hrani. Ova studija upoređuje inovativne metode
valorizacije nusproizvoda koprive u skladu sa principima kružne bioekonomije. Zelene tehnike, uključujući
ultrazvučnu i ekstrakciju uz pomoć netermalne plazme, korišćene su za efikasan oporavak bioaktivnih jedinjenja
iz nusproizvoda koprive.
Upoređeni su i proučavani tretmani i rastvarači (mešavine voda i voda/etanol) kako bi se ispitala njihova
selektivnost prema antioksidativnim jedinjenjima koja su pogodni kao supstrati za biotransformacije. Ekstrakti
su korišćeni kao supstrati za rast Ligilactibacillus salivarius ATCC 11741, soja bakterija mlečne kiseline sa
probiotičkim potencijalom. Ekstrakti su liofilizovani i kasnije rekonstituisani vodom, da bi se dobio medijum na
bazi vode za rast L. salivarius. Procenjivane su antioksidativne aktivnosti, ABTS, DPPH i ukupni fenolni
sadržaj, kao i rast L. salivarius. Dalje, biotransformacija vodenih ekstrakata fermentacijom sa L. salivarius je
potvrđena HPLC analizom. Fermentacija je poboljšala kvalitet ekstrakta povećanjem koncentracije fenolnih
jedinjenja, i to kofeinske kiseline (44%), hlorogenske kiseline (35%) i derivata kafeinske kiseline (44%), uz
održavanje visoke stope rasta ispitivanog mikroorganizma. DPPH test je pokazao visoku aktivnost od 234 trolok
ek/g dm u fermentisanim ekstraktima dobijenim primenom netermalne plazme. Iako se netermalna plazma u
nekim slučajevima koristi u antimikrobne svrhe, L. salivarius je pokazao visoki rast i u ekstraktima dobijenim uz
primenu netermalne plazme i u ekstraktima ekstrahovanim uz asistenciju ultrazvukom. Fermentacija sa L.
salivarius bila je direktno povezana sa povećanjem koncentracije biološki aktivnih jedinjenja, što otvara nove
mogućnosti za biotransformaciju ekstrakata, potencijalno i sa drugim bakterijama mlečne kiseline za dobijanje
novih specifičnih proizvoda fermentacije.
Fermentisani vodeni ekstrakti su pokazali značajan potencijal kao simbiotici sa antioksidativnim i postbiotičkim
svojstvima. Stabilnost fermentisanih ekstrakata treba dalje ispitati kako bi se predložio najbolji put za njihovu
eksploataciju, ali povećana biološka aktivnost sugeriše da bi njihova primena mogla da se proteže od
funkcionalne hrane do dijetetskih suplemenata i kozmetičkih sastojaka
Подготовка, карактеризација, атсорпција и проценка на антимикробната активност на зеолити функционализирани со силан
No full textIn this work, the preparation and comparative analysis of two adsorbents based on silane-modified natural and synthetic zeolite for adsorbing silver ions from aqueous solutions and the assessment of the possibility of their application as antibacterial agents against two strainsof bacteria was conducted. (3-Aminopropyl) triethoxysilane (APTES) was employed for modification, the presence of which in the ob-tained samples was verified by thermal andBrunauer-Emmett-Teller (BET) analysis, as well as infrared spectroscopy. Kinetic analysis indicated that the silver adsorption process followed the Lagergren pseu-do-second-order model, while the data fit best with the Freundlich isotherm, indicating multilayer adsorp-tion on the heterogeneous surface. The maximum adsorption capacities for silver ions were measured at 89.49 mg/g for natural and 61.19 mg/g for synthetic beta zeolite. The higher silver binding capacity was observed in natural zeolite, which ledto the conclusion that the key role in silver binding was played by exchangeable cations in the structure of this starting material and that the dominant mechanism was ion exchange. Both materials exhibited good antibacterial properties against Gram-negative Escherichia coliand the Gram-positive Staphylococcus aureus. These findings demonstrated the potential of APTES-modified zeolites as efficient adsorbents for silver ion removal and as antibacterial agents, paving the way for applications in water purification and antimicrobial technologiesВо оваа студија е извршена подготовка и споредбена анализа на два атсорбента базирани на природен и синтетички зеолит модифицирансо силан за атсорпција на сребрени јони од водни раствори, како и проценка на можноста за нивна примена како антимикробнисредства против два сојабактерии. За модификација беше користен (3-аминопропил)триетоксисилан (APTES), чие присуство во добиените примероци беше потврдено со термална анализа, Brunauer-Emmett-Teller –ова (BET) анализа и инфрацрвена спектроскопија. Кинетичката анализа укажа дека процесот на атсорпција на сребро се одвива според псевдо-втор ред на Lagergren, додека податоците најдобро се вклопуваат со изотерма на Freundlich, што укажува на повеќеслојна атсорпција на хетерогена површина. Максималните капацитети за атсорпција на сребрени јони изнесуваа 89,49 mg/g за природниот и 61,19 mg/g за синтетичкиот бета-зеолит. Поголемата способност за врзување на сребро беше забележана кај природниот зеолит, што доведе до заклучок дека клучна улога во врзувањето на сребро играат изменливите катјони во структурата на овој почетен материјал и дека доминантен механизам е јонската измена. И двата материјала покажаа добри антимикробни својства против Грам-негативната Escherichia coliи Грам-позитивниотStaphylococcus aureus. Овие наоди ја потврдуваат можноста за примена на зеолити модифициранисо APTES како ефикасни атсорбенти за отстранување на сребрени јони и како антимикробни средства, отворајќи пат за нивна употреба запрочистување на вода и во антимикробни технологии