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Stability of liposomal particles with encapsulated coumarin derivate
Get PDFCoumarin derivates possess several biological effects, including anti-inflammatory, antioxidant, anticoagulant, antitumor, insecticidal, anthelminthic, hypnotic, antifungal, and HIV protease inhibition properties [1,2]. Due to their solubility in organic solvents and insolubility in water and body fluids, their bioavailability is significantlylow. Thus, they can be encapsulated intoliposomal particles with the aim of overcoming the mentioned disadvan-tage[3]. Hence, in the present study, coumarin derivate was encapsulated in phospholipid liposomes and their stability was monitored for 60 days in terms of vesicle size, polydispersity index (PDI), zeta potential, and mobility.ExcellMater Conference 2024: Innovative Biomaterials for Novel Medical Devices, Belgrade, Serbia, April 10-12, 202
Innovative hydroxyapatite-based coatings for bone implants: A multifaceted approach
Get PDFTissue engineering strives for innovative solutions in addressing challenges associated with contemporary bone tissue implants. This study focuses on the electrophoretic deposition (EPD) of hydroxyapatite-based bioceramic composites containing antibacterial agents onto titanium surfaces. Two composite coatings, hydroxyapa-tite/chitosan (HAP/CS) and hydroxyapatite/chitosan/gentamicin (HAP/CS/Gent) were developed to combat issues such as poor adhesion, limited antibacterial potential, limited bioactivity, and potential toxicity of implant materials [1].ExcellMater Conference 2024: Innovative Biomaterials for Novel Medical Devices, Belgrade, Serbia, April 10-12, 202
Experimental, finite element and analytical characterization of hysteretic response of ductile connections with nailed angle brackets for mass timber structures
No full textEngineered wood products along with advanced processing and fabrication are pushing the limits of modern wood construction. Innovative concepts and applications facilitate the development of a new generation of structural systems. However, capacities of such systems are often governed by capabilities of the connections. This paper presents the experimental results with numerical and analytical models of angle brackets for prediction of load bearing capacity, stiffness, and ductility.
Three types of metal brackets in beam-column connections have been investigated and their performance has been studied in various loading arrangements. Detailed finite-element models of each connection have been developed to gain insights into their behavior. An analytical approach is also adopted to represent the connections. Comparison with test data suggests that
the models can reproduce results with good accuracy. The findings confirm feasibility of implementing ductile connections in practical mass timber structures
A novel source of biologically active compounds – The leaves of Serbian herbaceous peonies
No full textIn order to gain further insight into how various extraction techniques (maceration, microwave-, and ultrasound-assisted extractions) affect the chemical profile and biological activities of leaf extracts from Paeonia tenuifolia L., Paeonia peregrina Mill., and Paeonia officinalis L., this research was performed. The targeted chemical characterization of the extracts was achieved using the Ultra-High-Performance-Liquid-Chromatography-Linear-Trap-Mass-Spectrometry OrbiTrap instrumental technique, while Fourier Transform Infrared Spectroscopy was conducted to investigate the structural properties of the examined leaf extracts. According to the results, the species P. officinalis, Božurna locality as the origin of the plant material, and microwave-assisted extraction produced the maximum polyphenol yield, (491.9 ± 2.7 mg gallic acid equivalent (GAE)/mL). The ethanolic extracts exhibited moderate antioxidant activity as evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) and phosphomolybdenum tests. With MIC values of 0.125 mg/mL, the leaf extracts produced by ultrasound-assisted extraction and maceration (Deliblato sands and Bogovo gumno) had the best antibacterial activity against Pseudomonas aeruginosa and Salmonella Typhimurium. Ultrasound-assisted extraction has proven to produce the most effective antimicrobial agents. Inhibitory potential towards glucosidase, amylase, cholinesterases, and tyrosinase was evaluated in enzyme inhibition assays and molecular docking simulations. Results show that leaves of P. tenuifolia L. obtained by ultrasound-assisted extraction had the highest acetylcholinesterase and butyrylcholinesterase inhibitory activity. Namely, the complexity of the polyphenol structures, the extraction method, the used locality, and the different mechanisms of the reactions between bioactives from leaf extracts and other components (free radicals, microorganisms, and enzymes) are the main factors that influence the results of the antioxidant tests, as well as the antibacterial and enzyme-inhibitory activities of the extracts. Hydroxymethyl-phenyl pentosyl-hexoside and acetyl-hydroxyphenyl-hexoside were the first time identified in the leaf extract of the Paeonia species. Due to their proven biological activities and the confirmed existence of bioactive compounds, leaf extracts may find use in foodstuffs, functional foods, and pharmaceutical products
Tehnologija dobijanja impregniranih gaza na bazi alginata
No full textTehničko rešenje obuhvata formulaciju i tehnologiju dobijanja unapređenih gaza za tretman rana koje
su porozne, ojačane tkaninom i ne lepe se za ranu, pri tome upijaju sekret rane i regulišu njenu vlažnost,
dok kontrolisano mogu da otpuštaju različite aktivne komponente, kao što su npr. joni srebra ili cinka.
Prema tome, tehničko rešenje pripada oblasti materijali i hemijske tehnologije.Tehničko rešenje kategorije M82 - Novo tehničko rešenje (metoda) primenjeno na nacionalnom nivo
Are entrepreneurship and human capital the drivers of regional growth? Evidence from NUTS 3 sub-regions in Serbia
No full textU radu su predstavljeni različiti modeli regionalnog ekonomskog rasta prema kojima obrazovna struktura radno sposobnog stanovništva i preduzetnička aktivnost značajno doprinose unapređenju ekonomskih performansi. Takođe, analizira se uloga koju preduzetnička aktivnost i kvalitet ljudskog kapitala imaju na regionalni ekonomski rast u Republici Srbiji u periodu 2011-2020, na uzorku od 25 subregiona NUTS 3 nivoa. Rezultati ocenjivanja tri izabrana modela panela ukazuju da preduzetničke aktivnosti imaju vitalnu ulogu za rast bruto dodate vrednosti na nivou subregiona. S obzirom da glavni teorijski i brojni empirijski nalazi upućuju na to da nosioci regionalnog razvoja treba da budu preduzetnici koji poseduju odgovarajuća znanja, sposobnosti, kreativnost i veštine, preporuka za kreatore javnih politika je da kontinuirano rade na unapređenju poslovne klime i izgradnji stimulativnog preduzetničkog okruženja. Takav ambijent može podstaći visokoobrazovane pojedince da postanu ključni nosioci preduzetničkih aktivnosti.The paper presents different concepts of regional economic growth, according to which the educational structure of the working age population and entrepreneurial activity significantly contribute to the improvement of economic performance. It also analyzes the role of the entrepreneurial activity and the quality of human capital in regional economic growth in Serbia in the period from 2011 to 2020 using a sample of 25 NUTS 3 level sub-regions. The results of the evaluation of the three selected panel models indicate that entrepreneurial activities play a vital role in the growth of gross added value at the level of the sub-region. Given the fact that the main theoretical and numerous empirical findings suggest that bearers of regional development should be entrepreneurs who possess the appropriate knowledge, abilities, creativity and skills, the recommendation for the creators of public policies is to continuously work on improving the business climate and building a stimulating entrepreneurial environment. Such an environment can encourage highly educated individuals to become the key bearers of entrepreneurial activities
Novel eco-friendly sorbent derived from Acer pseudoplatanus seed for atenolol removal from pharmaceutical wastewater
No full textIn this paper, a novel sycamore maple seeds based activated carbon was synthesized, characterized and examined for sorption of atenolol from aqueous solutions. This low cost sorbent with great regeneration ability is shown to be a good option for fast uptake of atenolol in high extent due to its significant reactivity and developed mesoporous structure. For interpretation of the equilibrium data, Langmuir, Freundlich, and Temkin models were considered. All the models exhibited high fitting coefficients of determination with a contrasting vast deviation of estimated values for maximum sorption capacity towards experimental value of 93.71 mg/g. Considering kinetics, the pseudo-first and pseudo-second-order models, Elovich model, and the intraparticle diffusion model were employed for testing the experimental data. The process was shown to be fast with the greatest uptake extent in the initial 40 min from beginning of the process while equilibrium was attained after 2 h. Strong impacts of suspension pH, temperatures and sorbent dosage on the process were evidenced
Physically Crosslinked Poly(methacrylic acid)/Gelatin Hydrogels with Excellent Fatigue Resistance and Shape Memory Properties
No full textHydrogels endure various dynamic stresses, demanding robust mechanical properties. Despite significant advancements, matching hydrogels’ strength to biological tissues and plastics is often challenging without applying potentially harmful crosslinkers. Using hydrogen bonds as sacrificial bonds offers a promising strategy to produce tough, versatile hydrogels for biomedical and industrial applications. Poly(methacrylic acid) (PMA)/gelatin hydrogels were synthesized by thermally induced free-radical polymerization and crosslinked only by physical bonds, without adding any chemical crosslinker. The addition of gelatin increased the formation of hydrophobic domains in the structure of the hydrogels, which acted as permanent crosslinking points. The increase in PMA and gelatin contents generally led to a lower equilibrium water content (WC), higher thermal stability and better mechanical properties. The values of tensile strength and toughness reached up to 1.44 ± 0.17 MPa and 4.91 ± 0.51 MJ m−3, respectively, while the compressive modulus and strength reached up to 0.75 ± 0.06 MPa and 24.81 ± 5.85 MPa, respectively, with the WC being higher than 50 wt.%. The obtained values for compressive mechanical properties are comparable with super-strong hydrogels reported in the literature. In addition, hydrogels exhibited excellent fatigue resistance and biocompatibility, as well as great shape memory properties, which make them prominent candidates for a wide range of biomedical applications
STRUCTURAL ANALYSIS OF TWISTED AMIDES BASED ON THE SPIROHYDANTOIN SCAFFOLD WITH THE ANTICANCER ACTIVITY
No full textFive spirohydantoin derivatives were synthesized and analyzed by single crystal X-ray diffraction and DFT calculations (Figure 1). Compounds 1–3 and 5 crystallize as a syn conformation with respect to the ureic part (N1–C2(=O)–N3) of the hydanoin moiety, while compound 4 crystallize as an anti conformation. All compounds feature a distorted exocyclic amide bond that results from the twisting and pyramidalization of the N3 atom (Figure 2). Compound 2 with τ = 86.9° (97% of theoretical maximum) contains one of the most twisted amide bonds reported so far. The anticancer effects of the investigated compounds were evaluated against selected human cancer cell lines, as well as human normal lung fibroblasts (MRC5) cell lines. It appears that moderately distorted twisted amides with highly lipophilic substituents are the most potent within the series
OVREDNOTENJE OBNAŠANJA VARJENIH KONSTRUKCIJ V POGOJIH MALOCIKLIČNEGA UTRUJANJA
No full textWelded structures are exposed to constant variable loads during their exploitation in real conditions. A variable load affects the integrity and life of a welded structure; therefore, it is of practical importance to understand fatigue behavior, especially the behavior of welded structures under the impact of low-cycle fatigue. The effect of low-cycle fatigue is very prevalent in structures and an assessment of cyclic loading of a material entails modifications of its properties and characteristics related to the dependence of stress and strain. Since the stress-strain response during low-cycle fatigue is in the form of a hysteresis loop, this paper presents the application of one of the two most common relations for testing resistance to low-cycle fatigue, the Ramberg-Osgood relation, which is used to evaluate the behavior of a material, in this case a high-strength low-alloy steel welded joint.Varjene strukture oziroma konstrukcije so v realnih pogojih uporabe stalno obremenjene s spremenljivimi obremenitvami. Spreminjajoče se obremenitve vplivajo na integriteto in dobo trajanja varjene konstrukcije. Zato je pomembno razumeti, kako se določena konstrukcija obnaša v pogojih dinamičnega utrujanja. Še posebej občutljive so varjene konstrukcije v pogojih malocikličnega utrujanja. V teh vrstah struktur je vpliv malocikličnega utrujanja prevladujoč in ocena cikličnih obremenitev materiala zahteva modifikacije njegovih lastnosti in karakteristik, ki se nanašajo na odvisnost med napetostjo in deformacijo. Odgovor napetost-deformacija je med malocikličnim utrujanjem v obliki histerezne zanke in v tem članku avtorji predstavljajo uporabo ene od dveh najbolj splošnih enačb za testiranje malocikličnega utrujanja. To je Ramberg-Osgoodova enačba, ki se uporablja za ovrednotenje materiala in sicer v tem primeru za zvarne spoje iz malo legiranega jekla z visoko trdnostjo