Urchin-like trimanganese tetroxide (Mn3O4) particles were synthesized through a simple and gentle method, and characterized by XRD, XPS, FTIR, SEM, TEM, and UV-vis absorption. The intrinsic enzyme-like activity of urchin-like Mn3O4 particles was evaluated by 3, 3', 5, 5'-tetramethylbenzidine (TMB) in the absence of H2O2. The optimization of experiment conditions of urchin-like Mn3O4 particles on the oxidase-like activity was further investigated. It was exhibited that urchin-like Mn3O4 particles were best-performing with a highly oxidase-like catalytic activity in the model reaction. Due to the selective inhibition of glutathione (GSH) on the high oxidase-like activity of urchin-like Mn3O4 particles, a selective and sensitive colorimetric assay for GSH had been established. The method exhibited linear relationship over the GSH concentration range from 0.1 mu M to 30 mu M, with a low detection limit of 20.0 nM and a rapid response of less than 3 min. Based on high specificity of GSH inhibition, urchin-like Mn3O4 particles could be used to detect GSH concentration in human serum samples. [GRAPHICS]

Since December 2019, Coronavirus Disease 2019 (COVID-19) has emerged as a global pandemic. We aimed to investigate the clinical characteristics and analyzed the risk factors for prolonged viral RNA shedding. We retrospectively collected data from 112 hospitalized COVID-19 patients in a single center in Wuhan, China. Factors associated with prolonged viral RNA shedding (>= 28 days) were investigated. Forty-nine (43.8%) patients had prolonged viral RNA shedding. Patients with prolonged viral shedding were older and had a higher rate of hypertension. Proinflammatory cytokines, including interleukin-2R (IL-2R) and tumor necrosis factor-alpha (TNF-alpha), were significantly elevated in patients with prolonged viral shedding. Multivariate analysis revealed that hypertension, older age, lymphopenia and elevated serum IL-2R were independent risk factors for prolonged viral shedding. This comprehensive investigation revealed the distinct characteristics between patients with or without prolonged viral RNA shedding. Hypertension, older age, lymphopenia and high levels of proinflammatory cytokines may be correlated with prolonged viral shedding.