A co-type ductile film with high tensile strength and fast self-healing properties for shaped fruit preservation.

Traditional petroleum-based plastics have high energy consumption, require professional equipment, are non-degradable after use, and lack antibacterial properties, making it impossible to achieve long-lasting freshness in fruits and vegetables. Herein, we report a novel co-type film-forming method with low energy consumption and without production equipment, which uses PVA-borax gel as a substrate and adds a certain proportion of CMC and TA to prepare multifunctional CMC/TA@PVA-borax composite hydrogels (CTPB). The dynamic borax ester bonding and hydrogen bonding in the CTPB hydrogel results in an ultra-high tensile strength of more than 5500% and rapid self-healing within 8 s. Interestingly, hydrogels can be arbitrarily shaped and stretched like play dough and thus can be stretched into ductile films by co-type film formation. The antimicrobial properties of the hydrogel film can be attributed to the synergistic effects of TA and borax. The mussel structure of TA allows the hydrogel film to adhere directly to different surfaces for more effective bacterial killing. In addition, the hydrogel film has a high level of biosafety and biodegradability and shows good performance in fruit storage. This study provides a convenient and low-energy method for the preparation of films, which in part reduces the increasing environmental pollution caused by petroleum-based plastics.

One-pot co-crystallized hexanal-loaded ZIF-8/quaternized chitosan film for temperature-responsive ethylene inhibition and climacteric fruit preservation.

Controlling ethylene production and microbial infection are key factors to prolong the shelf life of climacteric fruit. Herein, a nanocomposite film, hexanal-loaded ZIF-8/CS (HZCF) with "nano-barrier" structure, was developed by a one-pot co-crystallized of ZIF-8 in situ growth on quaternized chitosan (CS) and encapsulation of hexanal into ZIF-8 via microporous adsorption. The resultant film realized the temperature responsive release of hexanal via the steric hindrance and hierarchical pore structure as "nano-barrier", which can inhibit ethylene production in climacteric fruit on demand. Based on this, the maximum ethylene inhibition rate of HZCF was up to 52.6 %. Meanwhile, the film exhibits excellent antibacterial, mechanical, UV resistance and water retention properties, by virtue of the functional synergy between ZIF-8 and CS. Contributed to the multifunctional features, HZCF prolonged the shelf life of banana and mango for at least 16 days, which is 8 days longer than that of control fruit. More strikingly, HZCF is washable and biodegradable, which is expected to replace non-degradable plastic film. Thus, this study provides a convenient novel approach to simplify the encapsulation of active molecule on metal-organic frameworks (MOFs), develops a packaging material for high-efficient freshness preservation, and helps to alleviate the survival crisis caused by food waste.

Phosphate-modified cellulose/chitosan with high drug loading for effective prevention of rice leaffolder (Cnaphalocrocis medinalis) outbreaks in fields.

The continuous infestation of pests has seriously affected rice growth, yield and quality. How to reduce the use of pesticides and effectively control insect pests is a bottleneck problem. Herein, based on hydrogen bonding and electrostatic interactions, we posed a novel strategy to construct emamectin benzoate (EB) pesticide loading system using self-assembled phosphate-modified cellulose microspheres (CMP) and chitosan (CS). CMP provides more binding sites for EB loading and CS coating further enhances the carrier loading capacity up to 50.75 %, which jointly imparted pesticide photostability and pH-responsiveness. The retention capacity of EB-CMP@CS in rice growth soil reached 101.56-fold that of commercial EB, which effectively improved the absorption of pesticides during rice development. During the pest outbreak, EB-CMP@CS achieved effective pest control by increasing the pesticide content in rice stems and leaves, the control efficiency of the rice leaffolder (Cnaphalocrocis medinalis) reached 14-fold that of commercial EB, and could maintain the effective pest control effect during the booting stage of rice. Finally, EB-CMP@CS-treated paddy fields had improved yields and were free of pesticide residues in the rice grain. Therefore, EB-CMP@CS achieves effective control of rice leaffolder in paddy fields and has potential application value in green agricultural production.

Preisolation measures and clinical features for pediatric patients with suspicious COVID-19.

Background: In December 2019, many cases of COVID-19 were reported in Wuhan City, Hubei Province, China. In the following 3 months, the disease out broke in China. Preisolation measures was used to screen out COVID-19 patients in the pediatric respiratory ward of our hospital. Aims: To investigate the new measures for screening COVID-19 patients and to analyze the clinical features of children with suspicious COVID-19. Methods: A total of 50 preisolated children with suspicious COVID-19 who were admitted to our hospital in Mianyang, China, between January 28 and March 5, 2020, were included. Patients presented with fever and cough or fever accompanied by vomiting and diarrhea. A detailed epidemiological history screening was performed. A real-time reverse-transcriptase-polymerase-chain-reaction (RT-PCR) was used to detect SARS-COV-2 nucleic acid. Low-dose chest computed tomography (CT) was applied when pneumonia was suspicious. Routine blood tests were performed to rule out COVID-19. Patients' data were collected, and the basic clinical features, epidemiological history, clinical manifestations, auxiliary examination results, and outcomes were analyzed and summarized. Results: No definite cases were detected, while two patients were suspected of having COVID-19. The pathogenic results of the 50 patients mainly included Mycoplasma pneumoniae, followed by Epstein-Barr virus, and rotavirus. Thirty-five patients suffered from bronchopneumonia. The preisolated patients had similar clinical and epidemiological characteristics as patients with fever, cough, vomiting, and diarrhea. Conclusions: Preisolation measures combined with pathogen screening can minimize the risk of hospital-acquired infections by preventing patients with suspicious COVID-19 from contacting other patients before they are explicitly excluded. Clinical analysis of the patients was helpful for clinical nursing management.