1. Upcycling wool and feather waste into nanofibers via eco-friendly hydrothermally assisted isolation of keratin : a promising approach to tunable functionalitiesSimona Strnad, Miša Žnidarič, Mojca Škerget, Maja Čolnik, Lidija Gradišnik, Uroš Maver, Lidija Fras Zemljič, 2025, izvirni znanstveni članek Opis: Hydrothermal degradation processes are a particularly promising eco-friendly approach to keratin isolation from biomass. They, however, result in products with a broad molecular weight distribution, which can be particularly unfavorable for fiber production. In this study, we aimed to determine whether hydrothermally degraded feather and wool waste is suitable to produce nanofibers that retain the key functional properties of keratin, such as antioxidant activity and biocompatibility. Keratin/PEO blends were used for needleless electrospinning of nanofibers cross-linked with two different cross-linkers, ethylene glycol diglycidyl ether (EGDE) and pentaerythritol triacrylate (PETA), to improve their stability to water. The surface tension, pH, turbidity, zeta potential, and protein concentration of the keratin extract solutions were analyzed. The morphology of the produced nanofibers was analyzed using a scanning electron microscope, the surface chemical structure by attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR analysis), and the cross-linking success by water contact angle measurements. The antioxidant capacity and the biocompatibility of the nanofiber mats with skin cells were investigated using a 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) vitality test, respectively. The results showed that despite the unfavorable starting materials with a wide molecular mass range from 3 to 15 kDa and low average molecular weights keratin products obtained by a green hydrothermal extraction process can be used to produce nanofibers with excellent antioxidant properties and skin cell biocompatibility. The cross-linking of the nanofibers resulted in hydrophobic nanofiber surfaces; however, it impaired their biocompatibility with skin cells compared to noncross-linked nanofibers.
Ključne besede: waste chicken feathers, wool, keratin nanofibers, greene xtraction process, subcritical water, hydrothermal isolation process, electrospinning, cross-linking
Objavljeno v DKUM: 28.11.2025; Ogledov: 0; Prenosov: 4
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2. Efficient and Green Isolation of Keratin from Poultry Feathers by Subcritical WaterMojca Škerget, Maja Čolnik, Lidija Fras Zemljič, Lidija Gradišnik, Tanja Živković Semren, Blanka Tariba Lovaković, Uroš Maver, 2023, izvirni znanstveni članek Opis: The isolation of keratin from poultry feathers using subcritical water was studied in a batch reactor at temperatures (120–250 °C) and reaction times (5–75 min). The hydrolyzed product was characterized by FTIR and elemental analysis, while the molecular weight of the isolated product was determined by SDS-PAGE electrophoresis. To determine whether disulfide bond cleavage was followed by depolymerization of protein molecules to amino acids, the concentration of 27 amino acids in the hydrolysate was analyzed by GC/MS. The optimal operating parameters for obtaining a high molecular weight protein hydrolysate from poultry feathers were 180 °C and 60 min. The molecular weight of the protein hydrolysate obtained under optimal conditions ranged from 4.5 to 12 kDa, and the content of amino acids in the dried product was low (2.53% w/w). Elemental and FTIR analyses of unprocessed feathers and dried hydrolysate obtained under optimal conditions showed no significant differences in protein content and structure. Obtained hydrolysate is a colloidal solution with a tendency for particle agglomeration. Finally, a positive influence on skin fibroblast viability was observed for the hydrolysate obtained under optimal processing conditions for concentrations below 6.25 mg/mL, which makes the product interesting for various biomedical applications.
Ključne besede: poultry feathers, subcritical water hydrolysis, keratin, physico-chemical characterization, cytotoxicity
Objavljeno v DKUM: 28.11.2023; Ogledov: 456; Prenosov: 173
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3. Primerjava ogrodij Node.js za razvoj spletnih strežnikov JavascriptNejc Novak, 2018, magistrsko delo Opis: V magistrskem delu smo na podlagi pregleda dokumentacije, izvedbe eksperimenta in analize pridobljenih podatkov predstavili in primerjali sedem aktualnih ogrodij Node.js. Izbrana aktualna ogrodja so bila Express, Hapi, Loopback, Feathers, Koa, Nest in Sails. Z deskriptivno analizo smo izpostavili posebnosti ogrodij in primerjali podobnosti med njimi. Za posamezno ogrodje smo predstavlili implementacijo storitev REST, povezovanje s podatkovno bazo, avtentikacijo in avtorizacijo uporabnika ter pripravo ogrodja za izvedbo v produkcijskemu okolju. Pri implementaciji sta bila izvedena eksperimenta primerjalne analize in merjenje zmogljivosti ogrodja z obremenitvenimi testi. Ugotovljeno je bilo, da ima ogrodje Nest na podlagi teoretičnega modela najboljšo oceno med analiziranimi ogrodji. Ugotovljeno je bilo tudi, da so ogrodja, ki podpirajo več funkcionalnosti, manj zmogljiva. Za nadaljnjo delo bomo zaključili poslovno logiko tipične rešitve in izvedli eksperimenta s spremembo podatkovnega modela in implementacijo avtentikacije z računi Google. Na podlagi eksperimenta bomo izvedli analizo opravljenih sprememb v rešitvi in ugotovili, kako ogrodje vpliva na vzdrževanje programske rešitve.
Ključne besede: Node.js, ogrodja, express, koa, hapi, nest, loopback, feathers, sails, spletni, strežnik, primerjava
Objavljeno v DKUM: 08.11.2018; Ogledov: 1418; Prenosov: 268
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