No abstract

Introduction: Knowledge is limited on the virologic course of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, particularly the time taken for viral clearance and the optimal time to discontinue isolation. This study aims to identify the clinical and demographic factors influencing the time taken for viral clearance in patients with COVID-19 to determine the optimal isolation period. Methods: This two-center retrospective observational cohort study was conducted between March 1 and June 31, 2020. Patients with COVID-19, which was confirmed by real-time reverse transcription polymerase chain reaction, were included. Data were extracted from medical records. The positive duration, which was defined as the period from the day of symptom onset to the negative conversion day, was assessed using a generalized linear model. Results: We included 63 patients. The mean positive duration was 20 days. The positive duration was significantly shorter for patients younger than 30 years of age and those between 30 and 60 years of age than for patients older than 60 years of age. We observed a more scattered distribution of the positive duration in older patients than in younger patients. Conclusions: Younger patients who recovered from COVID-19 took less time to clear SARS-CoV-2 than older patients; thus, a classification of the isolation periods based on age could be considered. A uniform viral clearance period for older patients may be difficult to determine because of biases such as underlying medical conditions. Further surveillance measures are recommended to determine the viral clearance time and the optimal isolation period.

No abstract

No abstract

No abstract

A thermodynamic analysis of the Pu U B ternary system has been carried out using the CALPHAD method. The formation energies of the boride phases MB 2 , MB 4 , MB 12 of this system obtained from first principles calculation were utilized to compensate for the lack of experimental information on the phase boundaries and thermodynamic properties of this system. The optimized thermodynamic parameters reproduced the characteristic features of binary phase diagrams quite well. The liquidus surface and isothermal sections were calculated. According to the calculated results, the liquidus temperature was raised with increasing B content.

No abstract