Synergistic antimicrobial effect of lactocin AL705 and nisin combined with organic acid salts against Listeria innocua 7 in broth and a hard cheese

The effectiveness of antimicrobial mixtures against Listeria innocua 7, used as a L. monocytogenes surrogate, was investigated in broth and a food system. Synergistic effects were found for nisin (Nis), potassium sorbate (PS), calcium propionate (CP) and sodium lactate (SL), Nis + PS being the most effective binary mixture that exhibited listericidal activity in broth. To assess the effect of adding lactocin AL705 (AL705) to Nis + organic acid salt combinations, tridimensional isobolograms were generated. Sub-MIC combinations of the antimicrobials exerted bactericidal activity against L. innocua 7 after AL705 addition to the binary mixtures. However, when applied on Sardo cheese contaminated with L. innocua 7 (initial inoculum 4.45 ± 0.06 CFU g⁻¹), only Nis + PS + AL705 produced count reductions respect to the control, reaching 3.04 ± 0.35 CFU g⁻¹ counts after 15 days at 15 °C. Ternary combinations containing AL705 showed potential to reduce antimicrobial usages for L. innocua 7 inhibition.     

Effect of gas-phase tortuosity on the mechanical properties of low-density polyolefin open-cell foams at low- and high-strain rates

This paper describes the mechanical behavior in compression, at both low- and high-strain rates, of several low-density open-cell polyolefin-based foams with different gas phase interconnectivities and different levels of gas-phase tortuosity. The mechanical properties of the open-cell polyolefin foams have been compared with two different references: an open-cell low tortuous foam based on flexible polyurethane and closed-cell polyolefin foams. One the one hand, at low-strain rates, it has been observed that the mechanical performance is controlled by the open-cell content and the properties of the polymeric matrix, being the influence of tortuosity small. On the other hand, the influence of the level of tortuosity is critical to high-strain rates. In fact, it has been demonstrated that open-cell polyolefin foams with high tortuosity (HT) present an unexpected mechanical behavior, showing excellent mechanical properties, which are even similar to that of closed-cell polyolefin materials with the same chemical composition. Therefore, low-density polyolefin foams with HT have a unique mechanical performance strongly influenced by the strain rate. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48468.     

Tuning the pH-responsiveness capability of poly(acrylic acid-co-itaconic acid)/NaOH hydrogel: Design,swelling, and rust removal evaluation

The swelling behavior of poly(acrylic acid-co-itaconic acid)/NaOH hydrogel as well as its ability for iron and copper rust removal was studied and established for the first time. Through an experimental design, the influence of the synthesis parameters on hydrogel response was determined. It was found that pH-responsiveness dependence of hydrogel determines its application. In alkaline media, the hydrogel acted as superabsorbent, while in acidic, the most outstanding property was its pickling capability that allowed to clean carbon steel and copper metallic surfaces. Infrared, thermogravimetry, and scanning electron microscopy were performed to determine copolymer formation, thermal properties, and morphology. Metallic crystallographic phases formed during the corrosion processes were determined by X-ray diffractometer. Hydrogel adhesiveness followed by diffusion and dissolution of metal oxides species was identified as the main steps in the rust removal mechanism. This method offers a new, environmentally friendly perspective to eliminate corrosion from metallic surfaces compared with traditional strategies. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48403.     

Determination of tylosin in milk samples by poly(ethylene terephthalate)-based molecularly imprinted polymer

Poly(ethylene terephthalate)-based molecularly imprinted polymers (MIPs) were synthesized, and their recognition capability was evaluated. Adsorption isotherm was described by the Langmuir model and the maximum adsorption capacity of MIP_Ty reached 172.4 mg g⁻¹ in water at pH 6.2. A recognition coefficient of 1.17 was obtained. A solid-phase extraction cartridge was manufactured and its behavior was evaluated for tylosin extraction from aqueous and milk samples. An off-line SPE-UV method was applied. An acceptable linearity was obtained in the range of 1–20 μg ml⁻¹ and the average recovery at three spike levels in milk samples was higher than 92%. The limit of quantification was 2.6 × 10⁻² μg ml⁻¹. The manufactured SPE cartridge has a great potential for clean-up processes in complex media. The cartridge offers a fast and sensitive option to the existing sorbents for extracting this drug from milk samples.     

Assessing plausibility of scientific claims to support high-quality content in digital collections

International Journal on Digital Libraries - This paper presents a formalization and extension of a novel approach to support high-quality content in digital libraries. Building on the concept of...