Synergistic bactericidal effect and mechanism of ultrasound combined with Lauroyl Arginate Ethyl against Salmonella Typhimurium and its application in the preservation of onions.

In the present study, the synergistic bactericidal effect and mechanism of ultrasound (US) combined with Lauroyl Arginate Ethyl (LAE) against Salmonella Typhimurium were investigated. On this basis, the effect of US+LAE treatment on the washing of S. Typhimurium on the surface of onions and on the physical and chemical properties of onion during fresh-cutting and storage were studied. The results showed that treatment with US+LAE could significantly (P < 0.05) reduce the number of S. Typhimurium compared to US and LAE treatments alone, especially the treatment of US+LAE (230 W/cm2, 8 min, 71 µM) reduced S. Typhimurium by 8.82 log CFU/mL. Confocal laser scanning microscopy (CLSM), flow cytometry (FCM), protein and nucleic acid release and N-phenyl-l-naphthylamine (NPN) assays demonstrated that US+LAE disrupted the integrity and permeability of S. Typhimurium cell membranes. Reactive oxygen species (ROS) and malondialdehyde (MDA) assays indicated that US+LAE exacerbated oxidative stress and lipid peroxidation in cell membranes. Field emission scanning electron microscopy (FESEM) demonstrated that US+LAE treatment caused loss of cellular contents and led to cell crumpling and even lost the original cell morphology. US+LAE treatment caused a significant (P < 0.05) decrease in the number of S. Typhimurium on onions, but there was no significant (P > 0.05) effect on the color, hardness, weight and ascorbic acid content of onions. This study elucidated the synergistic antibacterial mechanism of US+LAE and verified the feasibility of bactericidal effect on the surface of onions, providing a theoretical basis for improving the safety of fresh produce in the food industry and to propose a new way to achieve the desired results.

Antibacterial effect of ultrasound and ß-citronellol against Listeria monocytogenes and its application in carrot preservation.

This study investigated the antibacterial effects of ultrasound (US), ß-citronellol (CT), and a combination of the two treatments on Listeria monocytogenes. Results showed that US or CT alone did not show apparent antibacterial effect (0.02-0.76 log CFU/mL reduction). The combined treatment showed obviously inactivate effect of L. monocytogenes, the populations of L. monocytogenes decreased by 8.93 log CFU/mL after US (253 W/cm2, 20 kHz) + 0.8 mg/mL CT treatment. US + CT treatment also had a significant (P < 0.05) antibacterial effect on isolates of L. monocytogenes from three different serotypes. In this study, the damage of US + CT on cell morphology had been observed using field emission scanning electron microscopy, while the damage to cell membranes by US + CT was observed by confocal laser scanning microscopy and flow cytometry. Meanwhile, the uptake of N-phenyl-l-naphthylamine and the absorbance at 260 and 280 nm also indicated that the combined treatment disrupted the permeability and integrity of L. monocytogenes membranes. Reactive oxygen species and malondialdehyde assays showed that US + CT exacerbated cellular oxidative stress and lipid peroxidation. In addition, the US + CT treatment reduced L. monocytogenes by 3.14-4.24 log CFU/g on the surface of carrots. Total phenolic and carotenoid contents in carrots were elevated after US + CT treatment. During storage, compared to control, US + CT did not significantly (P > 0.05) change the surface color of carrots but significantly (P < 0.05) decreased both hardness and weight, and has an impact on the sensory. This study showed that US + CT is a promising cleaning method that will provide new ideas for the preservation of fresh agricultural produce.

MXene derived Ti3C2/TiO2/Ag persistent photocatalyst with enhanced electron storage capacity for round-the-clock degradation of organic pollutant.

Persistent photocatalysis has garnered significant attention due to its ability to sustain catalytic activity in dark by storing electrons. However, the practical application of persistent photocatalysis is hindered by limited electron storage capacity. Herein, we synthesized and demonstrated that Ti3C2/TiO2/Ag persistent photocatalyst has good electron storage capability. The electron storage capacity of Ti3C2/TiO2/Ag is up to 0.125 µmol/mg, which is 2.5 times that of Ti3C2/TiO2. The enhanced electron storage capacity resulted in improved dark-reaction activity because more electrons react with oxygen to form more radicals, as evidenced by degradation experiments of various organics. Especially, persistent photocatalytic degradation of tetracycline hydrochloride by Ti3C2/TiO2/Ag was achieved under natural outdoor conditions (from 2:00p.m. to 8:00p.m.). Additionally, the aid of oxidants such as peroxymonosulfate (PMS) can further improve the dark-reaction activity. TiO2/Ti3C2/Ag/PMS system exhibits excellent efficacy in removing tetracycline hydrochloride, oxytetracycline, rhodamine b, methyl orange, and methylene blue, with removal rates reaching 79.5 %, 81.4 %, 98.9 %, 99.1 %, and 99.2 %, respectively (15 min of light-reaction and 45 min of dark-reaction). This work provides a new strategy to enhance electron storage capacity and demonstrates that decoupling of light-reaction and dark-reaction may provide a new opportunity for photocatalytic removal of pollutants around the clock.

Overcoming Catastrophic Forgetting in Continual Learning by Exploring Eigenvalues of Hessian Matrix.

Neural networks tend to suffer performance deterioration on previous tasks when they are applied to multiple tasks sequentially without access to previous data. The problem is commonly known as catastrophic forgetting, a significant challenge in continual learning (CL). To overcome the catastrophic forgetting, regularization-based CL methods construct a regularization-based term, which can be considered as the approximation loss function of previous tasks, to penalize the update of parameters. However, the rigorous theoretical analysis of regularization-based methods is limited. Therefore, we theoretically analyze the forgetting and the convergence properties of regularization-based methods. The theoretical results demonstrate that the upper bound of the forgetting has a relationship with the maximum eigenvalue of the Hessian matrix. Hence, to decrease the upper bound of the forgetting, we propose eiGenvalues ExplorAtion Regularization-based (GEAR) method, which explores the geometric properties of the approximation loss of prior tasks regarding the maximum eigenvalue. Extensive experimental results demonstrate that our method mitigates catastrophic forgetting and outperforms existing regularization-based methods.

Barriers and facilitators to implementing evidence based mental health practice in primary schools / 中国学校卫生

Objective@#To explore the facilitators and barriers of the implementation of evidence based mental health practice, in order to provide practical experience for promoting the development of evidence based mental health services in primary schools in China.@*Methods@#Semi structured interviews were conducted with 4 education bureau managers, 8 school administrators, 7 classroom teachers, and 7 treatment providers after providing evidence based practice in 10 primary schools in Henan Province, China. Data was analyzed using thematic analysis.@*Results@#Evidence based practice in primary schools faced multiple factors at the macro level, school level, and individual level. A total of 8 facilitators and 9 barriers were extracted. Among these factors, some factors were particularly striking. These included the "exclusion" of teacher title evaluation system, time conflict between practice and school schedule, stigmatization of mental health and mismatch between perceived effectiveness of services and expectations.@*Conclusion@#Evidence based mental health practice is feasible in Chinese schools. The implementation process needs to take full account of macro, school and individual multi level factors to move evidence based mental health services from theory and data to practice in China.