Background: We compared the temporal changes of immunoglobulin M (IgM), IgG, and IgA antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleoprotein (N), spike 1 subunit (S1), and receptor-binding domain (RBD), and neutralizing antibodies (NAbs) against SARS-CoV-2 in patients with coronavirus disease 2019 (COVID-19) to understand the humoral immunity in COVID-19 patients for developing drugs and vaccines for COVID-19. Methods: A total of five confirmed COVID-19 cases in Nissan Tamagawa Hospital in early August 2020 were recruited in this study. Using a fully automated chemiluminescence immunoassay analyzer, we measured the levels of IgG, IgA, and IgM against SARS-CoV-2 N, S1, and RBD and NAbs against SARS-CoV-2 in COVID-19 patients' sera acquired multiple times in individuals from 0 to 76 days after symptom onset.Results: IgG levels against SARS-CoV-2 structural proteins increased over time in all cases but IgM and IgA levels against SARS-CoV-2 showed different increasing trends

The ‘subsurface disposal’ concept has been proposed for relatively higher-activity low-level waste (LLW) in Japan. This concept includes a low-permeability layer (LPL) made of bentonite material and a low-diffusion layer (LDL) made of dense cementitious material. The influence of gas generation and migration on the mechanical stability of the engineered barrier system (EBS) is one of the issues for long-term performance assessment of the disposal facility. In this study, coupled hydromechanical modelling and analyses are carried out in order to evaluate the mechanical stability of the system. Two gas generation rate cases are simulated: (1) a reference case; and (2) a conservative case. It is found from the analyses that the tensile stress developed in the cementitious components due to accumulated gas pressure is lower than the tensile strength of the materials, and that stress developed in the LPL remains compressive apart from at the interface between the LPL and the LDL, which suggests that opening could occur at the interface. These results indicate that the gas pressure would not mechanically damage the EBS of the subsurface disposal even if a relatively high gas generation rate were assumed.

ObjectivesTo compare the temporal changes of IgM, IgG, and IgA antibodies against the SARS-CoV-2 nucleoprotein, S1 subunit, and receptor binding domain and neutralizing antibodies (NAbs) against SARS-CoV-2 in patients with COVID-19.MethodsA total of five patients in Nissan Tamagawa Hospital, Tokyo, Japan confirmed COVID-19 from August 8, 2020 to August 14, 2020 were investigated. Serum samples were acquired multiple times from 0 to 76 days after symptom onset. Using a fully automated CLIA analyzer, we measured the levels of IgG, IgA, and IgM against the SARS-CoV-2 N, S1, and RBD and NAbs against SARS-CoV-2.ResultsThe levels of IgG antibodies against SARS-CoV-2 structural proteins increased over time in all cases but IgM and IgA levels against SARS-CoV-2 showed different increasing trends among individuals in the early stage. In particular, we observed IgA antibodies increasing before IgG and IgM in 3/5 cases. The NAb levels against SARS-CoV-2 increased and kept above 10 AU/mL more than around 70 days after symptom onset in all cases. Furthermore, in the early stage, NAb levels were more than cut off value in 4/5 COVID-19 patients some of whose antibodies against RBD didn’t exceed 10 AU/mL.ConclusionsOur findings indicate that patients with COVID-19 should be examined for IgG, IgA and IgM antibodies against SARS-CoV-2 structural proteins and NAbs against SARS-CoV-2 in addition to conventional antibody testing methods for SARS-CoV-2 (IgG and IgM kits) to analyze the diversity of patients’ immune mechanisms.