Background:Since the pandemic outbreak of coronavirus disease 2019 (COVID-19), the health system capacity in highly endemic areas has been overwhelmed. Approaches to efficient management are urgently needed. We aimed to develop and validate a score for early prediction of clinical deterioration of COVID-19 patients.
Our understanding of the protective immunity, particularly the long-term dynamics of neutralizing antibody (NAbs) response to SARS-CoV-2, is currently limited. We enrolled a cohort of 545 COVID-19 patients from Hubei, China, who were followed up up to 7 months, and determined the dynamics of NAbs to SARS-CoV-2 by using a surrogate virus neutralization test (sVNT). In our validation study, sVNT IC50 titers and the neutralization rate measured at a single dilution (1:20) were well correlated with FRNT titers (r = 0.85 and 0.84, respectively). The median time to seroconversion of NAbs was 5.5 days post onset of symptoms. The rate of positive sVNT was 52% in the first week, reached 100% in the third week, and remained above 97% till 6 months post onset. Quantitatively, NAbs peaked in the fourth week and only a quarter of patients had an estimated peak titer of >1000. NAbs declined with a half-time of 61 days (95% CI: 49–80 days) within the first two months, and the decay deaccelerated to a half-time of 104 days (95% CI: 86–130 days) afterward. The peak levels of NAbs were positively associated with severity of COVID-19 and age, while negatively associated with serum albumin levels. The observation that the low-moderate peak neutralizing activity and fast decay of NAbs in most naturally infected individuals called for caution in evaluating the feasibility of antibody-based therapy and vaccine durability. NAbs response positively correlated with disease severity, warning for the possibility of repeat infection in patients with mild COVID-19.
The ceramic printing and dyeing waste-water was treated by catalytic wet oxidation. The catalytic oxidation reaction was carried out under the conditions of 50 mg/L metal ion concentration, 180 °C of reaction temperature, 2.5 MPa of oxygen partial pressure and 500 rpm of stirring speed, and the time of catalytic oxidation was set at 90 min. Comparing the effect of structural auxiliaries and blank group on COD removal rate of effluent, the structural auxiliaries have no effect on effluent, that is, no catalytic effect; Comparing the blank group without adding catalyst, the copper nitrate has the highest cod removal rate of 72.5% for waste-water, so it can be used as the best homogeneous catalyst to treat waste-water. The order of catalytic effect from high to low is: Cu(NO3)2 > CuSO4 > Fe(NO3)3 > Fe2(SO4)3 > Co(NO3)2 > Cr(NO3)3 > Ni(NO3)2 > AgNO3 > Zr(NO3)4. Among the nine types of homogeneous catalysts, the most effective Cu(NO3)2•H2O catalyst treated the ceramic printing and dyeing waste-water, the COD decreased from 3775 mg/L to 1038 mg/L and the COD removal rate reached 72.5%, when the catalyst was not added under the same operating conditions. The COD removal rate of water samples was increased by 32.9%.
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