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Abstract Reductive amination by amine dehydrogenases is a green and sustainable process that produces only water as the by-product. In this study, a continuous flow process was designed utilizing a packed bed reactor filled with co-immobilized amine dehydrogenase wh84 and glucose dehydrogenase for the highly efficient biocatalytic synthesis of chiral amino alcohols. The immobilized amine dehydrogenase wh84 exhibited better thermo-, pH and solvent stability with high activity recovery. (S)-2-aminobutan-1-ol was produced in up to 99% conversion and 99% ee in the continuous flow processes, and the space-time yields were up to 124.5 g L-1 d-1. The continuous reactions were also extended to 48 h affording up to 91.8% average conversions. This study showcased the important potential to sustainable production of chiral amino alcohols in continuous flow processes.

Beetle femur–tibial joints can bear large loads, and the joint structure plays a crucial role. Differences in living habits will lead to differences in femur–tibial joint structure, resulting in different mechanical properties. Here, we determined the structural characteristics of the femur–tibial joints of three species of beetles with different living habits. The tibia of Scarabaeidae Protaetia brevitarsis and Cetoniidae Torynorrhina fulvopilosa slide through cashew-shaped bumps on both sides of the femur in a guide rail consisting of a ring and a cone bump. The femur–tibial joint of Buprestidae Chrysodema radians is composed of a conical convex tibia and a circular concave femur. A bionic structure design was developed out based on the characteristics of the structure of the femur–tibial joints. Differences in the failure of different joint models were obtained through experiments and finite element analysis. The experimental results show that although the spherical connection model can bear low loads, it can maintain partial integrity of the structure and avoid complete failure. The cuboid connection model shows a higher load-bearing capacity, but its failure mode is irreversible deformation. As key parts of rotatable mechanisms, the bionic models have the potential for wide application in the high-load engineering field.

Dung beetle leg joints exhibit a remarkable capacity to support substantial loads, which is a capability significantly influenced by their surface microstructure. The exploration of biomimetic designs inspired by the surface microstructure of these joints holds potential for the development of efficient self-locking structures. However, there is a notable absence of research focused on the surface microstructure of dung beetle leg joints. In this study, we investigated the structural characteristics of the surface microstructures present in dung beetle leg joints, identifying the presence of fish-scale-like, brush-like, and spike-like microstructures on the tibia and femur. Utilizing these surface microstructural characteristics, we designed a self-locking structure that successfully demonstrated functionality in both the rotational direction of the structure and self-locking in the reverse direction. At a temperature of 20 °C, the biomimetic closure featuring a self-locking mechanism was capable of generating a self-locking force of 18 N. The bionic intelligent joint, characterized by its unique surface microstructure, presents significant potential applications in aerospace and various engineering domains, particularly as a critical component in folding mechanisms. This research offers innovative design concepts for folding mechanisms, such as those utilized in satellite solar panels and solar panels for asteroid probes.

As a typical insulating material, Al2O3 serves as the signal isolation device in multi-layer ceramic NOx sensors. However, the application of Al2O3-based insulating materials is limited by the co-firing compatibility between Al2O3 and yttria-stabilized zirconia (YSZ). In the present study, Al2O3 green tapes with different contents of γ-Al2O3 and SiO2–B2O3 (Si–B) are developed to promote the integration of Al2O3-based insulating material and YSZ. The sintering shrinkage of the obtained Al2O3 green tapes is greatly influenced by the ratio of γ-Al2O3 to α-Al2O3 at 1450 °C, e.g., the maximum shrinkage reaches 17.34% when the γ-Al2O3 to α-Al2O3 ratio is 1:2. The addition of Si–B greatly increases the low density of Al2O3 tapes due to the pores generated during the firing process of the ultrafine γ-Al2O3 powders. The sintering density increases to 97.1% when the Si–B content is 15 wt. %, and the sintering shrinkage reaches a relatively higher value of 17.25%. The obtained Al2O3-based insulating materials show a greatly co-firing matching performance with the YSZ green tapes. This work will contribute to further investigation of ceramic co-firing studies.

5YSZ (5 mol. %Y2O3 stabilized ZrO2) solid electrolytes play a key role in NOx sensors for their important ion conduction performance in the sensing process. In this study, the influence of sintering and test temperature on 5YSZ solid electrolytes was investigated. The 5YSZ solid electrolyte was prepared by the tape casting process, followed by the sintering process. The ionic conductivity of the 5YSZ solid electrolyte sintered at 1450 °C is higher than that of other samples. The conductivity and activation energy of grain interior and grain boundary showed opposite tendency. The performance of ion conductivity was attributed to (1) the higher test temperature being applied to the working electrolyte and accelerated transfer efficiency and (2) enhanced diffusion of oxygen ions, which increased through the formation of dense structure.

Abstract Background As a natural antibacterial cationic peptide, ε-poly-l-lysine (ε-PL) is applied as a food preservative. However, the mechanism of ε-PL against Staphylococcus aureus (S. aureus) has not been elucidated. Especially, its antimicrobial mechanism at the metabolomics has not been yet thoroughly described. Results This work aimed at clarifying the antibacterial activity and mechanism of ε-PL against S. aureus. Effects of ε-PL with different concentration on cell morphology, cell wall, and membrane integrity were investigated. Furthermore, the effect of ε-PL on metabolite properties of S. aureus was also studied. The results revealed that ε-PL disrupted the cell wall and membrane integrity of treated cells. ε-PL induced the structural change of peptidoglycan in cell wall, causing cell wall more fragile. Meanwhile, the permeability of the S. aureus cell membrane was increased by ε-PL. More importantly, ε-PL with different concentration could cause different effects on metabolic pathways of S. aureus. ε-PL with high concentration could directly restrain the central carbon metabolism. However, ε-PL with low concentration could only inhibit the glycolytic pathway. Conclusion These results showed that the antimicrobial mechanism of ε-PL against S. aureus was a synergistic action.

ε-Polylysine (ε-PL), a natural preservative with broad-spectrum antimicrobial activity, has been widely used as a green food additive, and it is now mainly produced by Streptomyces in industry. In the previous study, strain 6#-7 of high-yield ε-PL was obtained from the original strain TUST by mutagenesis. However, the biosynthesis mechanism of ε-PL in 6#-7 is still unclear. In this study, the metabolomic analyses of the biosynthesis mechanism of ε-PL in both strains are investigated. Results show that the difference in metabolisms between TUST and 6#-7 is significant. Based on the results of both metabolomic and enzymatic activities, a metabolic regulation mechanism of the high-yield strain is revealed. The transport and absorption capacity for glucose of 6#-7 is improved. The enzymatic activity benefits ε-PL synthesis, such as pyruvate kinase and aspartokinase, is strengthened. On the contrary, the activity of homoserine dehydrogenase in the branched-chain pathways is decreased. Meanwhile, the increase of trehalose, glutamic acid, etc. makes 6#-7 more resistant to ε-PL. Thus, the ability of the mutagenized strain 6#-7 to synthesize ε-PL is enhanced, and it can produce more ε-PLs compared with the original strain. For the first time, the metabolomic analysis of the biosynthesis mechanism of ε-PL in the high-yield strain 6#-7 is investigated, and a possible mechanism is then revealed. These findings provide a theoretical basis for further improving the production of ε-PL.

In recent years, polymeric hydrogels have appeared promising matrices for enzyme immobilization to design, signify and expand bio-catalysis engineering. Therefore, the development and deployment of polymeric supports in the form of hydrogels and other robust geometries are continuously growing to green the twenty-first-century bio-catalysis. Furthermore, adequately fabricated polymeric hydrogel materials offer numerous advantages that shield pristine enzymes from denaturation under harsh reaction environments. For instance, cross-linking modulation of hydrogels, distinct rheological behavior, tunable surface entities along with elasticity and mesh size, larger surface-volume area, and hydrogels’ mechanical cushioning attributes are of supreme interest makes them the ideal candidate for enzyme immobilization. Furthermore, suitable coordination of polymeric hydrogels with requisite enzyme fraction enables pronounced loading, elevated biocatalytic activity, and exceptional stability. Additionally, the unique catalytic harmony of enzyme-loaded polymeric hydrogels offers numerous applications, such as hydrogels as immobilization matrix, bio-catalysis, sensing, detection and monitoring, tissue engineering, wound healing, and drug delivery applications. In this review, we spotlight the applied perspective of enzyme-loaded polymeric hydrogels with recent and relevant examples. The work also signifies the combined use of multienzyme systems and the future directions that should be attempted in this field.

Phenylalanine ammonia lyase (PAL) is a key enzyme for production of L-phenylalanine. Currently, PAL is mainly obtained from Rhodotorula PAL However, Rhodotorula PAL exhibits poor stability, which limits its industrial application. In this study, bioimprinting cross-linked enzyme aggregates of PAL (PAL-iCLEAs) is developed by combining cross-linked enzyme aggregates technology and imprinted enzyme method. The most optimal imprinting molecule substrate is screened. Moreover, some characteristics of the PAL-iCLEAs are examined. The results show that the most suitable substrates for preparing PAL-iCLEAs is tran-cinnamic acid. The optimal temperature and pH was 50 ℃ and 10.5, respectively. In addition, PAL-iCLEAs shows good reusability, the recovery of PAL activity still remained 32% after reusing 9 times.

In this study, phenylalanine ammonia lyase (PAL) is used as model, and the cross-linked enzyme aggregates of PAL with crude-pored microspherical silica core (NH-PAL-CLEAs) are prepared. The conditions for the preparation of NH-PAL-CLEAs are optimized. Moreover, some characteristics of the NH-PAL-CLEAs are examined. The optimized conditions for preparing NH-PAL-CLEAs are as follows: 117.75 mg silica, 0.2% (v/v) glutaraldehyde and 1 mL free PAL solution (2 U). Under optimized conditions, the maximum activity recovery of NH-PAL-CLEAs reaches 25%. Compared with PAL-CLEAs, the resulting NH-PAL-CLEAs can be easily separated from the reaction mixture by natural precipitation without centrifugation and filtration treatments. Moreover, NH-PAL-CLEAs show superior operational stability. This technique not only overcomes the difficulty to recover CLEAs due to their small particle sizes and soft for many industrial applications, but also reduces production cycle and energy consumption. As a result, this technique shows superior application prospect for enzyme immobilization.

Ba0.6Sr0.4TiO3/Mg0.9Zn0.1O (BST/MZO) ceramic composites with different MZO contents were prepared by traditional ceramic process. The crystal structure, fracture surface morphology, and dielectric properties were systematically investigated. The results show that the BST/MZO ceramic composites possess diphase structure, dense, and uniform morphology. The composites have relatively low dielectric loss (in the order of 10−3) at microwave frequency. The ceramics all retain substantial tunability (more than 20% at 8 kV/mm DC field) and excellent dielectric strength (more than 19.5 kV/mm). The BST-50 wt% MZO sample has the optimal FOM value (about 256) and should be a better candidate for tunable microwave applications. [ABSTRACT FROM AUTHOR]

Objective: The present study observed the clinical outcomes of the sodium cantharidinate/vitamin B6/GP regimen in the treatment of middle-late stage Non-small-cell lung carcinoma (NSCLC). Materials and Methods: Eighty-six cases of NSCLC were selected and randomized into two groups. Forty-five cases in the treatment group were subject to 30 ml cantharidinate/vitamin B6+ GP regimen, for four 21-day cycles. Forty-one cases in the control group were subject to regular GP regimen, for four 21-day cycles. Results: The effectiveness rate was 57.8% in the treatment group and 36.6% in the control group, suggesting statistical difference (P < 0.05); life quality in the treatment group was significantly better than that in the control group (P < 0.05); the occurrence rate of the toxic/adverse effects were significantly lower in the treatment group compared with that in the control group (P < 0.05). Conclusion: Sodium cantharidinate/vitamin B6/GP regimen had fair effectiveness and synergistically improved the clinical outcomes. It lowered the toxic/adverse effects and its application is worth further investigation and promotion. [ABSTRACT FROM AUTHOR]