Insight into the mechanism of high hydrostatic pressure effect on inhibitory efficiency of three natural inhibitors on polyphenol oxidase.

The development of natural inhibitors of polyphenol oxidase (PPO) is crucial in the prevention of enzymatic browning in fresh foods. However, few studies have focused on the effect of subsequent sterilization on their inhibition efficiency. This study investigated the influence and mechanism of high hydrostatic pressure (HHP) on the inhibition of PPO by epigallocatechin gallate (EGCG), cyanidin-3-O-glucoside (C3G), and ferulic acid. Results showed that under the conditions of 550 MPa/30 min, the activity of EGCG-PPO decreased to 55.92%, C3G-PPO decreased to 81.80%, whereas the activity of FA-PPO remained stable. Spectroscopic experiments displayed that HHP intensified the secondary structure transformation and fluorescence quenching of PPO. Molecular dynamics simulations revealed that at 550 MPa, the surface interaction between PPO with EGCG or C3G increased, potentially leading to a reduction in their activity. In contrast, FA-PPO demonstrated conformational stability. This study can provide a reference for the future industrial application of natural inhibitors.

Application of AI-assisted MRI for the identification of surgical target areas in pediatric hip and periarticular infections.

OBJECTIVE: To develop an AI-assisted MRI model to identify surgical target areas in pediatric hip and periarticular infections. METHODS: A retrospective study was conducted on the pediatric patients with hip and periarticular infections who underwent Magnetic Resonance Imaging(MRI)examinations from January 2010 to January 2023 in three hospitals in China. A total of 7970 axial Short Tau Inversion Recovery (STIR) images were selected, and the corresponding regions of osteomyelitis (label 1) and abscess (label 2) were labeled using the Labelme software. The images were randomly divided into training group, validation group, and test group at a ratio of 7:2:1. A Mask R-CNN model was constructed and optimized, and the performance of identifying label 1 and label 2 was evaluated using receiver operating characteristic (ROC) curves. Calculation of the average time it took for the model and specialists to process an image in the test group. Comparison of the accuracy of the model in the interpretation of MRI images with four orthopaedic surgeons, with statistical significance set at P < 0.05. RESULTS: A total of 275 patients were enrolled, comprising 197 males and 78 females, with an average age of 7.10 ± 3.59 years, ranging from 0.00 to 14.00 years. The area under curve (AUC), accuracy, sensitivity, specificity, precision, and F1 score for the model to identify label 1 were 0.810, 0.976, 0.995, 0.969, 0.922, and 0.957, respectively. The AUC, accuracy, sensitivity, specificity, precision, and F1 score for the model to identify label 2 were 0.890, 0.957, 0.969, 0.915, 0.976, and 0.972, respectively. The model demonstrated a significant speed advantage, taking only 0.2 s to process an image compared to average 10 s required by the specialists. The model identified osteomyelitis with an accuracy of 0.976 and abscess with an accuracy of 0.957, both statistically better than the four orthopaedic surgeons, P < 0.05. CONCLUSION: The Mask R-CNN model is reliable for identifying surgical target areas in pediatric hip and periarticular infections, offering a more convenient and rapid option. It can assist unexperienced physicians in pre-treatment assessments, reducing the risk of missed and misdiagnosis.

Frequency, Characteristics and Outcome of Adult Patients with Multiple Consecutive Healthcare-Associated Infections Undergoing Extracorporeal Membrane Oxygenation: A Retrospective Analysis.

BACKGROUND: Data on multiple consecutive healthcare-associated infections (HAIs) in patients undergoing extracorporeal membrane oxygenation (ECMO) are limited. We aim to identify the characteristics and outcomes of multiple, consecutive HAIs. METHODS: This retrospective cohort study included adult patients who underwent ECMO in a single cardiac intensive care unit in China from May 2015 to December 2022. The incidence, clinical characteristics, risk factors, and impact on in-hospital mortality were analyzed among patients with non-HAI, single HAI, and multiple HAIs. The pathogens and sites of each new episode of infection were evaluated and compared. RESULTS: Of 192 patients, 92 (47.92%) developed 141 separate infections, with 41 (21.35%) experiencing multiple infections during a single ECMO period. Respiratory tract infections (RTIs) constituted the majority (75.89%), and Gram-negative bacteria were the predominant pathogens (71.63%). The proportion of RTIs decreased from 86.9% in the first infection episode to 14.3% in the third (p < 0.001), while bloodstream infections increased from 10.9% to 57.1% (p < 0.001). Furthermore, from the first to the third HAI, the proportion of Gram-positive bacteria increased from 9.8% to 42.9% (p = 0.032). Prolonged ECMO duration was the only independent risk factor for multiple consecutive HAI (OR = 1.220; p < 0.001). CONCLUSIONS: The frequency of consecutive multiple HAIs during ECMO support was high, with distinct microbiological changes between initial and subsequent HAIs.

1-Methylcyclopropene and UV-C Treatment Effect on Storage Quality and Antioxidant Activity of 'Xiaobai' Apricot Fruit.

The 'Xiaobai' apricot fruit is rich in nutrients and is harvested in summer, but the high temperature limits its storage period. To promote commercial quality and extend shelf life, we investigated the effectiveness of Ultraviolet C (UV-C) combined with 1-methylcyclopropene (1-MCP) treatment on 'Xiaobai' apricot fruit stored at 4 ± 0.5 °C for 35 days. The results revealed that the combination treatment of 1-MCP and UV-C performed better than either UV-C or 1-MCP alone in fruit quality preservation. The combination treatment could delay the increase in weight loss, ethylene production, and respiration rate; retain the level of soluble solid content, firmness, titratable acid, and ascorbic acid content; promote the total phenolics and flavonoids accumulation; improve antioxidant enzyme activity and relative gene expression, and DPPH scavenging ability; and reduce MDA, H2O2, O2.- production. The combined treatment improved the quality of apricot fruit by delaying ripening and increasing antioxidant capacity. Therefore, combining UV-C and 1-MCP treatment may be an effective way to improve the post-harvest quality and extend the storage period of the 'Xiaobai' apricot fruit, which may provide insights into the preservation of 'Xiaobai' apricot fruit.

Effects of cuticular wax on the postharvest physiology in fragrant pear at different storages.

BACKGROUND: Epidermal wax is an important factor affecting the storage quality of fruits and vegetables. Previous studies have shown that the epidermal wax of fruits undergoes significant changes during storage, but there are few studies on the effects of different storage methods on the changes in waxes and the relationship with storage quality. To investigate the effect of cuticular wax on the postharvest physiology in fragrant pear, equal numbers of fragrant pear fruits were stored in room temperature storage (control), cold storage and controlled atmosphere (CA) storage environs, respectively. RESULTS: Gas chromatography-mass spectrometry analysis revealed that the prevailing compositions of cuticular wax of fragrant pear were alkanes, alkenes, alcohols, aldehydes, esters and fatty acids. Compared with the control, cold storage and CA storage significantly inhibited changes in postharvest physiology, total wax contents and wax compositions of fragrant pear, and the effects of CA storage were more pronounced than cold storage. Under different storage methods, total wax contents and wax compositions show different correlations with various physiological indicators. CONCLUSION: The results obtained in the present study indicate that cold storage and CA storage altered the fragrant pear cuticular wax contents and constituents, thus changing the postharvest physiology quality. The changes in the metabolism of wax components caused by the changes in storage environment mainly affect the changes in the hardness of fragrant pears. The present study provides a theoretical basis for the preservation and storage of fruits. © 2022 Society of Chemical Industry.

Comparative analysis of total wax content, chemical composition and crystal morphology of cuticular wax in Korla pear under different relative humidity of storage.

The cuticular wax of Korla pear stored under different relative humidity (0 ± 1 ℃, 50-55%, 70-75% and 90-95%) was examined in terms of total wax content, chemical composition and crystal morphology. The cuticular wax was composed of alkanes, olefins, fatty acids, alcohols, aldehydes, esters and terpenoids. High humidity maintained the content of total wax, alkanes and aldehydes at sufficient levels, especially C29 alkane and C18 aldehyde, which could positively regulate the quality of the pear fruits. Cuticular wax contributes to the capacity of preserving water, maintaining cell wall and delaying senescence. Scanning electron microscopy showed that wax crystals appeared as numerous platelets with irregular ovate crystals, high humidity delayed the transformation of wax structure. Taken together, high humidity delayed the ripening and aging by effectively maintaining wax, which was essential for postharvest storage and provide a reference for the production of synthetic wax for Korla pear fruits.