With the spread of COVID-19 in China at the beginning of 2020, MOOCs, as a kind of currently popular online learning resource, have played a dominant role in higher education field. However, chiefly focusing on teaching organization and learning process in MOOCs, previous studies have paid inadequate attention to lecturers’ discourse. In order to provide some useful views on this issue, this study investigates EFL lecturers’ metadiscourse in Chinese university MOOCs to sketch its distinctive pattern across course types. Based on a self-built corpus, this research adopted interpersonal model as theoretical foundation and analyzed the frequency and functions of metadiscourse by AntConc 3.5.7 and IBM SPSS 23. Findings suggest that specific educational context in MOOCs leads to low frequency of metadiscourse and its use is mainly aimed at the enhancement of intelligibility, reliability, and interactivity. Besides, course types with different knowledge structures also exert certain influence on metadiscourse usage. Course types focusing on procedural knowledge (i.e. the knowledge related to practical process) tend to apply metadiscourse to enhance intelligibility and interactivity, while the ones stressing declarative knowledge (i.e. the knowledge related to explicit facts) attach more importance to reliability. Lastly, the paper concludes with implications for EFL lecturers’ metadiscourse in Chinese university MOOCs.The coronavirus disease 2019 (COVID-19) pandemic reached Kenya in March 2020 with the initial cases reported in the capital city Nairobi and in the coastal area Mombasa. As reported by the World Health Organization, the outbreak of COVID-19 has spread across the world, killed many, collapsed economies and changed the way people live since it was first reported in Wuhan, China, in the end of 2019. As at the end of December 2020, it had led to over 2.8 million confirmed cases in Africa with over 67 thousand deaths. The trend poses a huge threat to global public health. Understanding the early transmission dynamics of the infection and evaluating the effectiveness of control measures is crucial for assessing the potential for sustained transmission to occur in new areas. We employed a SEIHCRD mathematical transmission model with reported Kenyan data on cases of COVID-19 to estimate how transmission varies over time. The model is concise in structure, and successfully captures the course of the COVID-19 outbreak, and thus sheds light on understanding the trends of the outbreak. The next generation matrix approach was adopted to calculate the basic reproduction number (R0) from the model to assess the factors driving the infection. The model illustrates the effect of mass testing on COVID-19 as well as individual self initiated behavioral change. The results have significant impact on the management of COVID-19 and implementation of prevention policies. The results from the model analysis shows that aggressive and effective mass testing as well as individual self initiated behaviour change play a big role in getting rid of the COVID-19 epidemic otherwise the rate of infection will continue to increase despite the increased rate of recovery.Severe acquired respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly spread worldwide and acquired multiple mutations in its genome. Orf3a, an accessory protein encoded by the genome of SARS-CoV-2, plays a significant role in viral infection and pathogenesis. BGB-16673 mw In the present in-silico study, 15,928 sequences of Orf3a reported worldwide were compared to identify variations in this protein. Our analysis revealed the occurrence of mutations at 173 residues of Orf3a protein. Subsequently, protein modelling was performed that revealed twelve mutations which can considerably affect the stability of Orf3a. Among the 12 mutations, three mutations (Y160H, D210Y and S171L) also lead to alterations in secondary structure and protein disorder parameters of the Orf3a protein. Further, we used predictive tools to identify five promising epitopes of B-cells, which resides in the mutated regions of Orf3a. Altogether, our study sheds light on the variations occurring in Orf3a that might contribute to alteration in protein structure and function.The development of a safe and effective SARS-CoV-2 vaccine is a public health priority. We designed subunit vaccine candidates using self-assembling ferritin nanoparticles displaying one of two multimerized SARS-CoV-2 spikes full-length ectodomain (S-Fer) or a C-terminal 70 amino-acid deletion (SΔC-Fer). Ferritin is an attractive nanoparticle platform for production of vaccines, and ferritin-based vaccines have been investigated in humans in two separate clinical trials. We confirmed proper folding and antigenicity of spike on the surface of ferritin by cryo-EM and binding to conformation-specific monoclonal antibodies. After a single immunization of mice with either of the two spike ferritin particles, a lentiviral SARS-CoV-2 pseudovirus assay revealed mean neutralizing antibody titers at least 2-fold greater than those in convalescent plasma from COVID-19 patients. Additionally, a single dose of SΔC-Fer elicited significantly higher neutralizing responses as compared to immunization with the spike receptor binding domain (RBD) monomer or spike ectodomain trimer alone. After a second dose, mice immunized with SΔC-Fer exhibited higher neutralizing titers than all other groups. Taken together, these results demonstrate that multivalent presentation of SARS-CoV-2 spike on ferritin can notably enhance elicitation of neutralizing antibodies, thus constituting a viable strategy for single-dose vaccination against COVID-19.Recent efforts to repurpose drugs to combat COVID-19 have identified Remdesivir as a candidate. It acts on the RNA-dependent, RNA polymerase (RdRp) of the SARS-CoV-2 virus, a protein complex responsible for mediating replication of the virus’s genome. However, its exact action mechanism, and that of other nucleotide analogue inhibitors, is not known. In this study, we examine at the molecular level the interaction of this drug and that of similar nucleotide analogue inhibitors, ribavirin and favilavir, by relying on atomistic molecular simulations and advanced sampling. By analyzing the binding free energies of these different drugs, it is found that all of them bind strongly at the active site. Surprisingly, however, ribavirin and favilavir do not bind the nucleotide on the complementary strand as effectively and seem to act by a different mechanism than remdesivir. Remdesivir exhibits similar binding interactions to the natural base adenine. Moreover, by analyzing remdesivir at downstream positions of the RNA, we also find that, consistent with a “delayed” termination mechanism, additional nucleotides can be incorporated after remdesivir is added, and its highly polar 1′-cyano group induces a set of conformational changes that can affect the normal RdRp complex function.