The novel coronavirus SARS‐CoV‐2 has prompted a worldwide pandemic and poses a great threat to public safety and global economies. Most present personal protective equipment (PPE) used to intercept pathogenic microorganisms is deficient in biocidal properties. Herein, we present green nanofibers with effective antibacterial and antiviral activities that can provide sustainable bioprotection by continuously producing reactive oxygen species (ROS). The superiority of the design is that the nanofibers can absorb and store visible light energy and maintain the activity under light or dark environment. Moreover, the nanofibers can uninterruptedly release ROS in the absence of an external hydrogen donor, acting as a biocide under all weather conditions. A facile spraying method is proposed to rapidly deploy the functional nanofibers to existing PPE, such as protective suits and masks. The modified PPE exhibit stable ROS production, excellent capacity for storing activity potential, long‐term durability, and high bactericidal (>99.9%) and viricidal (>99.999%) efficacies.
speed airflow scouring. Accordingly, the thermal protection system (TPS) must be applied on their surface to cope with the integrated heat load accumulated during flight. [2] The lightweight nature of TPS is critical in addressing the criteria for ultralong-range combat military weapons with high sound speeds and load capacities while considering the production cost in check. Kistler of Stanford University first proposed the concept of aerogel in 1931, [3] which was fabricated by exchanging the liquid in a wet gel by gas whilst guaranteeing that the internal structure did not collapse, becoming one of the lightest solid materials known to date. The abundance of internal nanoscale pore size and highly tortuous pore structure determine aerogel's excellent thermally insulation performance, with the thermal conductivity as low as 0.005 W m −1 K −1 . [4] NASA pioneered the use of aerogels as efficient insulating materials on several Mars rovers and spacecraft parts, such as the insulation assembly of Rover Mars batteries, the outer surface of vehicle decelerators, [5] etc., and is also advancing their application in extra-vehicular insulating suits. [6] Oxide ceramic aerogels have currently been the most rapidly developed in high-temperature insulation; however, due to the restrictions of crystallization-induced pulverization, large thermal expansion, and relatively low operating temperatures, for example, SiO 2 (650 °C), [7] ZrO 2 (1100 °C), [8] Al 2 O 3 (1300 °C), [9] and mullite (1400 °C), these aerogels and their composites suffer from severe strength deterioration and catastrophic structural failure during significant temperature gradient changes or long-term high-temperature exposure. [10] Conversely, carbon aerogels (CAs) maintain their mesoporous structure despite heat treatment over 2500 °C under a vacuum or inert atmosphere, showing favorable thermal stability at ultra-high temperatures. [11] In addition, they also have a much higher specific extinction coefficient (190 m 2 kg −1 ) than others (e.g., SiO 2 aerogel with 20 m 2 kg −1 ), which leads to lower radiative thermal conductivities. [12] Therefore, CAs are anticipated to be up-and-coming candidates for the TPS of hypersonic vehicles in conditions of severe heat flow density and ultra-high temperatures.The terms of CAs initially referred to carbonaceous substances that exist as 3D monoliths macroscopically and
Abstract. The objective of the present study was to evaluate the feasibility of using model drug metoprolol succinate (MS) as a pore former to modify the initial lag phase (i.e., a slow or non-release phase in the first 1-2 h) associated with the drug release from coated pellets. MS-layered cores with high drug-layering efficiency (97% w/w) were first prepared by spraying a highly concentrated drug aqueous solution (60% w/w, 70°C) on non-pareils without using other binders. The presence of MS in ethylcellulose (EC) coating solution significantly improved the coating process by reducing pellets sticking, which often occurs during organic coating. There may be a maximum physical compatibility of MS with EC, and the physical state of the drug in the functional coating layer of EC/MS (80:20) was simultaneously crystalline and noncrystalline (amorphous or solid molecule solution). The lag phase associated with hydroxypropylcellulose (HPC) as a pore former was not observed when MS was used as a pore former. The drug release from EC/ MS-coated pellets was pH independent, inversely proportional to the coating levels, and directly related to the pore former levels. The functional coating layer with MS as a pore former was not completely stabilized without curing. Curing at 60°C for 1 day could substantially improve the stability of EC/MScoated pellets. The physical state of the drug in the free film of EC/MS (85:15) changed partially from amorphous to crystal when cured at 60°C for 1 day, which should be attributed to the incompatibility of the drug with EC.
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