Search

The addition of adjunct culture has a significant impact on the quality of cheese. To screen adjunct culture with high protein hydrolysis and antioxidant capacity, this study evaluated 12 strains of lactic acid bacteria based on the acid production, protease activity, proteolysis, and antioxidant capacity. The potentially beneficial strain was used as adjunct culture to make quark cheese. The effect of adjunct culture on cheese quality was assessed by examining physicochemical indices, titration acidity changes, lactic acid bacteria count, texture alterations, and antioxidant activity during storage. Results showed that Lactobacillus kefiranofaciens XZ-54, which had a weak acid-producing capacity, high protease activity, protein hydrolysis, and antioxidant capacity, had the potential to be used as an adjunct fermenter for quark cheese. The addition of XZ-54 had no significant effect on the physicochemical parameters, hardness, and spread ability of quark cheese (P > 0. 05), and the viable counts of XZ-54 in the cheese were maintained above 107 CFU/ g during the 21-day storage period. Additionally, it significantly enhanced the DPPH free radical, ABTS cationic radical, and hydroxyl radical scavenging activities of the cheese. Therefore, Lactobacillus kefiranofaciens XZ-54 could be effectively employed as an adjunct culture in quark cheese, improving its antioxidant qualities and demonstrating significant potential for development and application. [ABSTRACT FROM AUTHOR]

Pruritus is often accompanied with bacterial infections, but the underlying mechanism is not fully understood. Although previous studies revealed that lipopolysaccharides (LPS) could directly activate TRPV4 channel and TRPV4 is involved in the generation of both acute itch and chronic itch, whether and how LPS affects TRPV4‐mediated itch sensation remains unclear. Here, we showed that LPS‐mediated TRPV4 sensitization exacerbated GSK101‐induced scratching behaviour in mice. Moreover, this effect was compromised in TLR4‐knockout mice, suggesting LPS acted through a TLR4‐dependent mechanism. Mechanistically, LPS enhanced GSK101‐evoked calcium influx in mouse ear skin cells and HEK293T cells transfected with TRPV4. Further, LPS sensitized TRPV4 channel through the intracellular TLR4‐PI3K‐AKT signalling. In summary, our study found a modulatory role of LPS in TRPV4 function and highlighted the TLR4‐TRPV4 interaction in itch signal amplification. [ABSTRACT FROM AUTHOR]

As environmental pollution continues to rise, the demand for biodegradable materials, particularly biodegradable foams, is steadily increasing. We prepared high-density foam using extended poly(butylene adipate-co-terephthalate) (E-PBAT) and poly(propylene carbonate) (PPC), with basalt fiber (BF) serving as the filler, through an extrusion process. We conducted a detailed study to investigate the impact of PPC and BF content on the foaming of E-PBAT. We conducted a detailed study on how PPC and BF content influence the foaming of E-PBAT. This investigation revealed the formation of various phase morphologies within the composites, including "island-sea," "quasi-co-continuous," and "co-continuous" structures, which, in turn, altered the cellular morphology. The BF network played a crucial role as a structural backbone, enhancing the composite material's modulus, yield strength, and rheological complex viscosity (|η*|). Additionally, fiber networks can also serve as nucleation sites to promote cell nucleation and increase cell density. A higher cell density allows for more effective force transfer when the foam experiences external pressures, thereby enhancing its mechanical properties. We also summarized the mechanisms behind the changes in phase structure and fiber content on cell morphology. This summary provides valuable guidance for research on the extrusion foaming of biodegradable materials. [ABSTRACT FROM AUTHOR]

In this study, acrylate (ACR) copolymer was used to toughen polylactide (PLA). Dynamic mechanical analysis and differential scanning calorimetry results showed that PLA was partially miscible with ACR. Isothermal crystalline behavior indicated that the incorporation of ACR significantly prevented the crystallization of PLA. The transmission electron micrograph showed that ACR was uniformly dispersed in PLA matrix. The mechanical properties of PLA could be improved by the addition of ACR. The analysis of yield stress indicated mild interfacial adhesion between PLA and ACR. Scanning electron micrograph of PLA/ACR blends revealed that the major toughening mechanism was matrix shear yield and plastic flow. Complex viscosity values of PLA/ACR blends were remarkably improved with the incorporation of ACR. Moreover, the van Gurp-Palmen plot, the rheological percolation threshold for the blends was lower than 15 wt%. The incorporation of ACR decreased the absorption coefficient (α), which was caused decreasing transmittance of PLA., INTRODUCTION Plastic materials have been widely applications in every aspect of life and industries. However, most of the conventional plastics are nonbiodegradable. Their accumulation in the environment has been a [...]

Long fibre-reinforced metal matrix composite materials, which are widely used in industry, have complex and diverse damage modes due to their structural characteristics. In this study, the progressive damage process and failure mode analysis of the SiCf/TC4 composite shafts were thoroughly investigated under single torsional loads. A bearing performance test was carried out, the damage process was monitored using acoustic emissions, and the fracture specimens were analysed using a scanning electron microscope (SME). More specifically, under reverse torque loading, the damage process was slow-varying, the interface was subjected to tensile force, and fracture occurred mostly in the form of interface cracking; further, the breaking load of the specimen was 11,812 Nm. Under forward loading, the damage process was fast-varying. The fibres were subjected to tensile forces, and the fracture form was mostly fibre fracture; the breaking load of the specimen was 10,418 Nm. Under torque loading, the first damage to the specimens appeared in the outermost layer of the composite material's reinforced section, and the initial cracking position was at the interface, expanding from the outside to the inside. Based on the principles of macro-mechanics and micro-mechanics theory, the cross-scale models were proposed, which contain the shaft with the same dimensions as the specimen and a micro-mechanics representative volume element (RVE) model. The initial interface damage load was 6552 Nm under reverse torque loading. Under forward loading, the initial interface damage load was 9108 Nm. In comparison to the acoustic emission test results, the main goal was to calculate the progressive damage process under the same conditions as the experiment, verifying the effectiveness of the cross-scale models. [ABSTRACT FROM AUTHOR]

With people's awareness of environmental protection, the requirement of eco‐quality is increasingly demanding, particularly a more profound reflection in the field of materials. Polylactic acid (PLA) is a hopeful biodegradable thermoplastic material while its adverse nature restricts the practical applications. In this work, a one‐step reactive extrusion method was adopted to improve some properties of PLA by melt blending with some active additives, including commercial epoxy‐based chain extender, that is, ADR4468 of BASF, Germany; thermoplastic polyurethane thermoplastic polyurethane (TPU) elastomer, that is, DN‐5380 of Dawn, China, and mineral nucleating agent talc, that is, AH250CL of Aihai, China. Their influences on mechanical properties and crystallization behaviors of PLA were explored, and the detailed mechanisms were also discussed. It is found that ADR chain extender played a key role in improving the strength and rigidity of the composites, and methylenediphenyl diisocyanate type TPU elastomer could significantly enhance the toughness and ductility of PLA materials, while talc had a positive impact on regulating the cooling crystallization behavior of PLA. In particular, only trace ADR4468 (0.4 wt%) could effectively enhance its tensile and flexural strengths of neat PLA by 6.3% and 13.4%, respectively. Reactive polyurethane with 5 wt% significantly improved its elongation at break by 36.5%. The micro‐sized talc‐nucleating agent enhanced the cooling crystallization degrees to 24.7% from 4.8% for PLA blended with trace chain extender. The analysis results indicated that the functional group reactions between the active additives and PLA played key roles in improving the related properties. The output has certain reference values for PLA modification strategy, and will pave a route for endowing PLA materials with specific and required nature. [ABSTRACT FROM AUTHOR]