The Analyses of High Infectivity Mechanism of SARS-CoV-2 and Its Variants

SARS-CoV-2 has high infectivity and some of its variants have higher transmissibility. To explore the high infectivity mechanism, the charge distributions of SARS-CoV, SARS-CoV-2, and variants of concern were calculated through a series of net charge calculation formulas. The results showed that the SARS-CoV-2 spike protein had more positive charges than that of SARS-CoV. Further results showed that the variants had similar but higher positive charges than preexisting SARS-CoV-2. In particular, the Delta variant had the greatest increase in positive charges in S1 resulting in the highest infectivity. In particular, the S1 positive charge increased greatly in the Delta variant. The S1 positive charge increased, and due to the large negative charge of angiotensin-converting enzyme-2 (ACE2), this resulted in a large increase in Coulomb’s force between S1 and ACE2. This finding agrees with the expectation that the positive charges in the spike protein result in more negative charges on SARS-CoV-2 antibodies than that of SARS-CoV. Thus, the infectivity of a novel SARS-CoV-2 variant may be evaluated preliminarily by calculating the charge distribution.

Transformations of actinides fission product yields due to post scission emission of nuclear particles:232Th

The "many ensembles" method was proposed to investigate the influence of nuclear particles' post-scission emission on mass and charge distributions of fission products. The post scission approximation had been used; each of these ensembles consists of the fission fragments after emission of chains of different lengths, both the beta (±β) particles and neutrons. The theory allows one to find the most probable two fragment clusters of fission products and study their evolution after the post-scission emission of nuclear particles. The isotope ²³²Th was chosen as an example, the fission fragments of which are intensively studied in the experiment. It is shown that the post-scission emission of nuclear particles eventually leads to the convergence of the asymmetric peaks, which looks like enhanced symmetric fission mode over asymmetric one for fission product yields. A comparison of the theoretical results and experimental data for the ²³²Th fission fragments indicates their satisfactory matching.