Search

This study presents the development of fibers with favorable properties for biodegradable wound dressings made from the Ecovio® (EC) polymer blend, composed of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT), incorporated with tea tree essential oil (TTE). TTE presented antimicrobial activity against Pseudomonas aeruginosa and Staphylococcus aureus, achieving minimal inhibitory concentrations (MIC) of 15 and 7.5 mg/mL, respectively. The TTE was mixed with EC in a binary chloroform and formic acid (85/15 v/v) mixture. The EC/TTE fibers were characterized by differential scanning calorimetry (DSC), Fourier-transform infrared with attenuated total reflectance (FTIR-ATR), and X-ray photoelectron spectroscopy (XPS), confirming the TTE in the fibers. The tests showed that TTE (0.5, 1.0, or 1.5 mL) improved the polymer blend's electrospinnability, leading to bead-free, homogenous, and smaller fiber diameters. TTE (1.5 mL or 75 w% concerning the EC) leads to homogeneous fibers with an average diameter of 278 ± 59 nm. TTE (75 w%) increased the wettability of the EC fibers from 120 ± 2° to 69 ± 1°. Preliminary bacterial adhesion and proliferation assays demonstrated that the EC/TTE fibers have anti-adhesive activity and demonstrate greater toxicity, which seems more toxic against P. aeruginosa than S. aureus after 24 h of incubation. Fluorescence and coagulation kinetics tests performed with human blood indicated that the EC/TTE fibers accelerate blood coagulation. The EC/TTE fibers exhibit promising chemical and biological properties (in vitro) for developing wound dressings. [ABSTRACT FROM AUTHOR]

Fungi (Neolentinus lepideus, Nl, and Trametes versicolor, Tv) impart wood rot, leading to economic and environmental issues. To overcome this issue, toxic chemicals are commonly employed for wood preservation, impacting the environment and human health. Surface coatings based on antimicrobial chitosan (CS) of high molar mass (145 × 105 Da) were tested as wood preservation agents using an innovative strategy involving ultra-pressurizing CS solutions to deposit organic coatings on wood samples. Before coating deposition, the antifungal activity of CS in diluted acetic acid (AcOOH) solutions was evaluated against the rot fungi models Neolentinus lepideus (Nl) and Trametes versicolor (Tv). CS effectively inhibited fungal growth, particularly in solutions with concentrations equal to or higher than 0.125 mg/mL. Wood samples (Eucalyptus sp. and Pinus sp.) were then coated with CS under ultra-pressurization at 70 bar. The polymeric coating deposition on wood was confirmed through X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM) images, and water contact angle measurements. Infrared spectroscopy (FTIR) spectra of the uncoated and coated samples suggested that CS does not penetrate the bulk of the wood samples due to its high molar mass but penetrates in the surface pores, leading to its impregnation in wood samples. Coated and uncoated wood samples were exposed to fungi (Tv and Nl) for 12 weeks. In vivo testing revealed that Tv and Nl fungi did not grow on wood samples coated with CS, whereas the fungi proliferated on uncoated samples. CS of high molar mass has film-forming properties, leading to a thin hydrophobic film on the wood surface (water contact angle of 118°). This effect is mainly attributed to the high molar mass of CS and the hydrogen bonding interactions established between CS chains and cellulose. This hydrophobic film prevents water interaction, resulting in a stable coating with insignificant leaching of CS after the stability test. The CS coating can offer a sustainable strategy to prevent wood degradation, overcoming the disadvantages of toxic chemicals often used as wood preservative agents. [ABSTRACT FROM AUTHOR]

This study presents fibers based on methacrylic acid–methyl methacrylate (Eudragit L100) as Cu(II) adsorbents, resulting in antimicrobial complexes. Eudragit L100, an anionic copolymer synthesized by radical polymerization, was electrospun in dimethylformamide (DMF) and ethanol (EtOH). The electrospinning process was optimized through a 22-factorial design, with independent variables (copolymer concentration and EtOH/DMF volume ratio) and three repetitions at the central point. The smallest average fiber diameter (259 ± 53 nm) was obtained at 14% w/v Eudragit L100 and 80/20 EtOH/DMF volume ratio. The fibers were characterized using scanning electron microscopy (SEM), infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR), and differential scanning calorimetry (DSC). The pseudo-second-order mechanism explained the kinetic adsorption toward Cu(II). The fibers exhibited a maximum adsorption capacity (qe) of 43.70 mg/g. The DSC analysis confirmed the Cu(II) absorption, indicating complexation between metallic ions and copolymer networks. The complexed fibers showed a lower degree of swelling than the non-complexed fibers. The complexed fibers exhibited bacteriostatic activity against Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. This study successfully optimized the electrospinning process to produce thin fibers based on Eudragit L100 for potential applications as adsorbents for Cu(II) ions in aqueous media and for controlling bacterial growth. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the influence a finishing diet containing natural additives fed for 94 days on animal performance, carcass, and meat quality characteristics of crossbred bulls (1/2 Angus × 1/2 Nellore). Forty-eight bulls (initial BW 318 ± 4.7 kg and initial age 22 months) were used in a completely randomised design. Bulls were fed one of four diets: (1) CON – Control; (2) CCO – addition of 4 g/animal.day of a mix of essential oils from castor bean and cashew; (3) MIX – addition of 4 g/animal.day of a mix of essential oils (oregano oils, castor bean, cashew); (4) YST – addition of 4 g/animal.day of yeast. Bulls were finished in feedlot (in individual pens) and slaughtered at an average weight of 469 ± 6.7 kg. Final BW, hot carcass weight and average daily gain were greater (P < 0.05) in MIX diet than in the three other diets. However, DM intake, G : F, fat thickness, longissimus muscle area, marbling, and meat colour were similar (P > 0.05) among the four diets. The carcass conformation score was higher (P < 0.05) for bulls that were fed with the YST diet and similar for the three other diets. Meat from CCO had a reduced (P < 0.05) cooking loss when compared with CON diet. Shear force from MIX diet had lesser values (P < 0.05) than meat from YST diet, and it was similar among CON and CCO diets. There was no diet effect (P > 0.05) on lipid oxidation, moisture, ash, and total lipids contents. C14:0, C14:1 n-9, C16:0, C18:1 n-9, C18:1 n-7 and C18:3 n-6 fatty acids in intramuscular fat from the longissimus muscle were affected by the inclusion of additives in the diets. SFA, MUFA, PUFA, n -3 and n -6 fatty acid percentages, and the ratios PUFA : SFA and n -6 : n -3 were similar (P > 0.05) among diets. In conclusion, adding a mix of oregano, castor bean, and cashew oils in the diet improved the performance of the bulls, but meat characteristics did not significantly change. Natural additives can modulate ruminal fermentation on high energetic density diets. The aim of this work was to study the effect of essential oils and yeast inclusion on cattle diets. Addition of natural compounds (oregano, castor bean, cashew oils and yeast) improved bull performance, without changing significantly meat characteristics. Natural additives could be an alternative for ionophores substitution. [ABSTRACT FROM AUTHOR]

BACKGROUND The aim of this work was to improve the nutritional quality of Nile tilapia meat through enriched diets with conjugated isomers of linolenic acid from tung oil. The transfer process of conjugated fatty acids ( CFAs) into fish muscle tissue was evaluated by gas chromatography-flame ionization detection ( GC-FID) and easy ambient sonic-spray ionization mass spectrometry ( EASI-MS). RESULTS The results showed that conjugated fatty acids were transferred from enriched diet for muscle tissue of Nile tilapia. Conjugated linoleic acids biosynthesis from conjugated linolenic acids was also observed after 10 days. Other important fatty acids such as docosahexaenoic ( DHA), eicosapentaenoic ( EPA) and arachidonic ( AA) acids were also identified over time; however, DHA showed the highest concentration when compared with EPA and AA compounds. CONCLUSION Therefore, the nutritional quality of Nile tilapia was improved through feeding with enriched diets. The ingestion of these fish may contribute to reaching adequate levels of daily CFA consumption. Furthermore, other important substances which play an important role in human metabolism, such as EPA, DHA and AA, can also be ingested together with CFA. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract The transesterification of frying waste oil for biodiesel synthesis can provide crude glycerol contaminated by aldehydes, ketones, methyl esters, heavy metals, anions, and other impurities. This fact has become an environmental problem being a huge challenge to recovery the glycerol from biodiesel synthesis by using frying oil as feedstock. This study depicts a novel strategy to treat residual glycerol produced from the frying oil transesterification. Crude glycerol is subjected to one pre-purification process by using a cationic and condensed tannin derivative (a functionalized polymer with amino moieties in its structure). This polymer is used as an efficient coagulant/flocculant agent. After pre-purification step, the glycerol is purified following treatments by ion exchange resins and water evaporation. Glycerol-based samples (crude, purified and a standard) are characterized through chromatography-mass spectroscopy, atomic absorption spectrometry, infrared spectroscopy, and nuclear magnetic resonance (1H and 13C). The impurity content based on aldehydes, methyl esters, chloride and, heavy metals are significantly reduced/removed, imparting purified glycerol of technical grade (~95 wt% purity). So, by combining both cationic tannin derivative and ion exchange resins, we can treat the crude glycerol obtained from the frying oil transesterification, following an eco-friendly and more economical process. Highlights • Frying oil transesterification produces a complex crude glycerol mixture. • A cationic tannin-based polymer is efficient for promoting flocculation. • The flocculation plays an essential role in the treatment of crude glycerol. • Glycerol of technical grade is obtained by using ion exchange resins. [ABSTRACT FROM AUTHOR]

Ecovio® is a hydrophobic, biodegradable, and synthetic polymer blend composed of poly(butylene adipate- co -terephthalate) and poly(acid lactic) polyesters. It is soluble in solvents of low polarity, being a challenge to obtaining thin and homogeneous electrospun Ecovio® fibers. Ecovio® blend solutions do not have electrospinnability due to the low viscosity and electrical conductivity. For overcoming this disadvantage, Ecovio® and Tween 20 were associated with a binary 85/15 chloroform/formic acid mixture. The formic acid (15 vol%) and Tween 20 (1.0 v% concerning the total solution volume) increased the Ecovio® electrospinnability, promoting thin fibers (average diameter of 253 nm). Tween 20 (1.0% v/v) reduced the surface tension from 29.50 to 28.92 mN/cm and increased the electrical conductivity and viscosity from 0.85 to 2.03 μS/cm and 26.02–27.13 mPa s. The solution parameters were adjusted, imparting Ecovio® solution electrospinnability. The Tween 20 induced a wettable fiber surface that immediately absorbed a water droplet after contact, reducing the water contact angle from 125° on Ecovio® fiber (488 nm) to 0° on Ecovio®/Tween 20 fiber (253 nm). The wettable Ecovio®/Tween 20 fiber adsorbed silver ions (Ag+) from an aqueous solution, promoting a reinforced (Elastic modulus of 2136 MPa) and wettable composite fiber after Ag + reduction. The determined Ag0 content was 8 μg per composite fiber gram. Ecovio®/Tween 20 fibers stabilized the AgNPs, imparting anti-adhesive and antimicrobial properties against Staphylococcus aureus (S. aureus) and Escherichia coli. The composite filter removed bacteria from water (S. aureus at 107 CFU/mL), reaching a removal efficiency of 99.99% in the first filtration. The biodegradable and antimicrobial composite filter can replace conventional harsh chemicals that treat water, including drinking water contaminated with bacteria. [Display omitted] • Tween 20 and formic acid improved the electrospinnability of polymer blends. • Tween 20 promoted wettable surfaces that adsorb Ag + ions. • The Ag + ions are reduced, imparting a composite filter. • The AgNPs reinforced the filter, supporting an elastic modulus of 2136 MPa. • The antimicrobial filter removed bacteria (99.99%) from water at 107 CFU/mL. [ABSTRACT FROM AUTHOR]