Mask decontamination methods (model N95) for respiratory protection: a rapid review

Background N95 respiratory protection masks are used by healthcare professionals to prevent contamination from infectious microorganisms transmitted by droplets or aerosols. Methods We conducted a rapid review of the literature analyzing the effectiveness of decontamination methods for mask reuse. The database searches were carried out up to September 2020. The systematic review was conducted in a way which simplified the stages of a complete systematic review, due to the worldwide necessity for reliable fast evidences on this matter. Results A total of 563 articles were retrieved of which 48 laboratory-based studies were selected. Fifteen decontamination methods were included in the studies. A total of 19 laboratory studies used hydrogen peroxide, 21 studies used ultraviolet germicidal irradiation, 4 studies used ethylene oxide, 11 studies used dry heat, 9 studies used moist heat, 5 studies used ethanol, two studies used isopropanol solution, 11 studies used microwave oven, 10 studies used sodium hypochlorite, 7 studies used autoclave, 3 studies used an electric rice cooker, 1 study used cleaning wipes, 1 study used bar soap, 1 study used water, 1 study used multi-purpose high-level disinfection cabinet, and another 1 study used chlorine dioxide. Five methods that are promising are as follows: hydrogen peroxide vapor, ultraviolet irradiation, dry heat, wet heat/pasteurization, and microwave ovens. Conclusions We have presented the best available evidence on mask decontamination; nevertheless, its applicability is limited due to few studies on the topic and the lack of studies on real environments.

Mask decontamination methods (model N95) for respiratory protection: a rapid review

Background: N95 respiratory protection masks are used by healthcare professionals to prevent contamination from infectious microorganisms transmitted by droplets or aerosols.Methods: We conducted a rapid review of the literature analyzing the effectiveness of decontamination methods for mask reuse. The database searches were carried out up to September 2020. The systematic review was conducted in a way which simplified the stages of a complete systematic review, due to the worldwide necessity on reliable fast evidences on this matter.Results: A total of 563 articles were retrieved of which 48 laboratory-based studies were selected. Fifteen decontamination methods were included in the studies. A total of 19 laboratory studies used Hydrogen peroxide, 21 studies used ultraviolet germicidal irradiation,4 studies used ethylene oxide, 11 studies used dry heat, 9 studies used moist heat, 5 studies used ethanol, two studies used isopropanol solution, 11 studies used microwave oven, 10 studies used sodium hypochlorite, seven studies used autoclave, three studies used electric rice cooker, one study used cleaning wipes, one study used bar soap, one study used water, one study used multi-purpose high-level disinfection cabinet and another one used chlorine dioxide. Five methods promising: hydrogen peroxide vapor, ultraviolet irradiation, dry heat, wet heat/pasteurization, and microwave ovens.Conclusions: We have presented the best available evidence on masks decontamination, nevertheless, its applicability are limited due to few studies on the topic and lack of studies on real environments.

Decontamination methods for respiratory protection mask model N95: a rapid review

Background: N95 respiratory protection masks are used by healthcare professionals to prevent contamination with infectious microorganisms transmitted by droplets or aerosols.Methods: We conducted a rapid review of the literature analyzing the effectiveness of decontamination methods for mask reuse. The review was carried out in September 2020 using a simplification of the formal systematic review process, which simplified the stages of a complete systematic review, including the exclusion of an assessment of study methodology.Results: A total of 563 articles were retrieved of which 48 laboratory-based studies were selected. Fifteen decontamination methods were included in the studies. Hydrogen peroxide was evaluated by 19 laboratory studies, ultraviolet germicidal irradiation by 21, ethylene oxide by 4, dry heat by 11, moist heat by 9, ethanol by 5, isopropanol solution by 2, microwave oven by 11, sodium hypochlorite by 10, autoclave by 7, electric rice cooker by 3, cleaning wipes by 1, bar soap and water 1, multi-Purpose High-Level Disinfection Cabinet by 1 and chlorine dioxide by 1. Five methods appear promising: hydrogen peroxide vapor, ultraviolet irradiation, dry heat, wet heat/pasteurization, and microwave ovens.Conclusions: Positive results should be considered with caution as they represent a small number of studies, reflect ideal laboratory conditions, and may have limited applicability in realistic situations and for health systems.

Concomitant polymorphic forms of 3-cyclopropyl-5-(2-hydrazinylpyridin-3-yl)-1,2,4-oxadiazole

The dipharmacophore compound 3-cyclopropyl-5-(2-hydrazinylpyridin-3-yl)-1,2,4-oxadiazole, C10H11N5O, was studied on the assumption of its potential biological activity. Two concomitant polymorphs were obtained on crystallization from isopropanol solution and these were thoroughly studied. Identical conformations of the molecules are found in both structures despite the low difference in energy between the four possible conformers. The two polymorphs differ crucially with respect to their crystal structures. A centrosymmetric dimer formed due to both stacking interactions of the `head-to-tail' type and N—H...N(π) hydrogen bonds is the building unit in the triclinic structure. The dimeric building units form an isotropic packing. In the orthorhombic polymorphic structure, the molecules form stacking interactions of the `head-to-head' type, which results in their organization in a column as the primary basic structural motif. The formation of N—H...N(lone pair) hydrogen bonds between two neighbouring columns allows the formation of a double column as the main structural motif. The correct packing motifs in the two polymorphs could not be identified without calculations of the pairwise interaction energies. The triclinic structure has a higher density and a lower (by 0.60 kcal mol−1) lattice energy according to periodic calculations compared to the orthorhombic structure. This allows us to presume that the triclinic form of 3-cyclopropyl-5-(2-hydrazinylpyridin-3-yl)-1,2,4-oxadiazole is the more stable.

The Photocatalytic Activity of Zns-TiO2 on a Carbon Fiber Prepared by Chemical Bath Deposition

This research prepared a TiO2, ZnS, and ZnS-TiO2 film on a carbon fiber, to produce TiO2/C-fiber, ZnS-C-fiber, and ZnS-TiO2/C-fiber by Chemical Bath Deposition (CBD). Results show that TiO2/C-fiber consist of anatase at 2θ 25.3 o and 54.6 o, rutile at 2θ 43.5 o and a carbon characteristic peak at 2θ of 24.5 o. Meanwhile, the characteristic peaks of ZnS on ZnS-TiO2/C-fiber present at 2θ of 27.91 o and 54.58 o. TiO2/C-fiber has a band gap energy of 3.60 eV, the ZnS/C-fiber of 3.73 eV; when those two catalyst combine, the gap energy is 3.15 eV indicating the interface charge transfer between ZnS-TiO2. Photocatalytic treatment of an isopropanol solution with TiO2/C-fiber as a catalyst and under UV light radiation present results peaks at 222- 224 nm and 265 nm, indicating the electronic transition of acetone. Meanwhile, the isopropanol degradation with ZnS-TiO2/C-fiber produced a new peak at 234-237 nm. The Quantum Yield, QY, of ZnS-TiO2/C-fiber is 6.96 x 10-4, higher than TiO2/C-fiber, i.e., 0.42 x 10-4. It indicates that ZnS provides a significant role in the photocatalytic activity through a red shift of light response and decreasing electron-hole recombination.

Chitosan-Pectin-Stearic Acid Film for Controlled-Release of Curcumin

The release of curcumin from chitosan-pectin-stearic acid films was studied in the variation of the pH of the buffer solutions, the addition of ethanol in the buffer solution, the amount of loaded curcumin, the amount of stearic acids in the films. The chitosan-pectin films were prepared by addition of 1% acetic acid solution of chitosan into 1% aqueous pectin solution, followed by addition of isopropanol solution of stearic acid. The films were characterized using FT-IR spectrophotometer. The study of curcumin release was performed by soaking the film in buffer-ethanol solutions for 6hand measuring the released curcumin by UV-Vis spectrophotometer. The kinetics of releasing curcumin was analyzed using Korsmeyer-Peppas equations. The result showed that the releasing of curcumin was influenced by the amount of loaded curcumin, the amount of stearic acid in the film and buffer pH of the solution. The optimum releasing rate at buffer pH 7 in 40% ethanol solution was obtained when the amount of curcumin loaded and stearic acid were c.a. 55.5 and 136.4 mg/g film, respectively, which the curcumin release achieved 66.04%. Releasing kinetics of the curcumin followed a Korsmeyer-Peppas model with a rate constant (k) of 7.5270 and n of 0.378. The curcumin release mechanism was mainly based on the diffusion mechanism.