Masks for COVID-19.

Sustainable solutions on fabricating and using a face mask to block the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread during this coronavirus pandemic of 2019 (COVID-19) are required as society is directed by the World Health Organization (WHO) toward wearing it, resulting in an increasingly huge demand with over 4 000 000 000 masks used per day globally. Herein, various new mask technologies and advanced materials are reviewed to deal with critical shortages, cross-infection, and secondary transmission risk of masks. A number of countries have used cloth masks and 3D-printed masks as substitutes, whose filtration efficiencies can be improved by using nanofibers or mixing other polymers into them. Since 2020, researchers continue to improve the performance of masks by adding various functionalities, for example using metal nanoparticles and herbal extracts to inactivate pathogens, using graphene to make masks photothermal and superhydrophobic, and using triboelectric nanogenerator (TENG) to prolong mask lifetime. The recent advances in material technology have led to the development of antimicrobial coatings, which are introduced in this review. When incorporated into masks, these advanced materials and technologies can aid in the prevention of secondary transmission of the virus.

Discussion on China's anti-epidemic response based on the Protocol on Prevention and Control of Coronavirus Disease 2019 from Chinese Authority.

Eight versions of the Protocol on Prevention and Control of Coronavirus Disease 2019 (COVID-19) (the Protocol) were issued successively by the Chinese authority to guide the local responses since the first COVID-19 case appeared in Wuhan, China. This study aimed to investigate the evolution of the overall strategy and specific measures in these Protocols, and several recommendations were provided after analysing China's response to the epidemic resurgence. As a result, we found a gradual expanding trend in case surveillance, early screening, and epidemiological investigation, as well as a progressively rigorous tendency in isolation measures and close contact management. With the Protocol's guidance, China had achieved success in several recent fights against domestic COVID-19 resurgences. The city lockdown and multiple city-wide nucleic acid tests adopted were deemed necessary in COVID-19 resurgence's battle. Besides, the large-scale distance centralised quarantine, which is, quarantine in a purpose-built isolation station away from communities where people under quarantine lived, was promoted in rural areas. China's anti-epidemic achievements provide ideas for the global battle against COVID-19.

High-gravity-driven process intensified approach toward Mn2+ doped Zn2GeO4 nanophosphors for deep-ultraviolet detecting

Deep-ultraviolet (DUV) light devices are receiving widely attention due to their potential use in sterilization and water purification, in particularly, during the COVID-19 pandemic. Photoluminescence detectors that demonstrate the existence of DUV light invisible to our eyes are of importance. Herein, we propose a process intensified approach via high-gravity reactive precipitation combined with hydrothermal synthesis for production of Mn2+ doped zinc orthogermanate (Zn2GeO4: Mn2+) nanophosphors for deep-ultraviolet detecting. The rotating packed bed (RPB) was used as the reactor for process intensification of the reactive precipitation and the whole processing time was significantly reduced. The Zn2GeO4: Mn2+ phosphors show green emission upon ultraviolet or near ultraviolet excitation. In optimized conditions, the products show a sub-microrod morphology with average size of about 200 nm. Under the excitation of 254 nm light, the Zn2GeO4: Mn2+ nanophosphors exhibit bright green emission at peak wavelength of 535 nm.

Can Masks Be Reused After Hot Water Decontamination During the COVID-19 Pandemic?

Masks have become one of the most indispensable pieces of personal protective equipment and are important strategic products during the coronavirus disease 2019 (COVID-19) pandemic. Due to the huge mask demand-supply gap all over the world, the development of user-friendly technologies and methods is urgently needed to effectively extend the service time of masks. In this article, we report a very simple approach for the decontamination of masks for multiple reuse during the COVID-19 pandemic. Used masks were soaked in hot water at a temperature greater than 56 °C for 30 min, based on a recommended method to kill COVID-19 virus by the National Health Commission of the People's Republic of China. The masks were then dried using an ordinary household hair dryer to recharge the masks with electrostatic charge to recover their filtration function (the so-called "hot water decontamination + charge regeneration" method). Three kinds of typical masks (disposable medical masks, surgical masks, and KN95-grade masks) were treated and tested. The filtration efficiencies of the regenerated masks were almost maintained and met the requirements of the respective standards. These findings should have important implications for the reuse of polypropylene masks during the COVID-19 pandemic. The performance evolution of masks during human wear was further studied, and a company (Zhejiang Runtu Co., Ltd.) applied this method to enable their workers to extend the use of masks. Mask use at the company was reduced from one mask per day per person to one mask every three days per person, and 122 500 masks were saved during the period from 20 February to 30 March 2020. Furthermore, a new method for detection of faulty masks based on the penetrant inspection of fluorescent nanoparticles was established, which may provide scientific guidance and technical methods for the future development of reusable masks, structural optimization, and the formulation of comprehensive performance evaluation standards.