Protective prototype-Beta and Delta-Omicron chimeric RBD-dimer vaccines against SARS-CoV-2.

Breakthrough infections by SARS-CoV-2 variants become the global challenge for pandemic control. Previously, we developed the protein subunit vaccine ZF2001 based on the dimeric receptor-binding domain (RBD) of prototype SARS-CoV-2. Here, we developed a chimeric RBD-dimer vaccine approach to adapt SARS-CoV-2 variants. A prototype-Beta chimeric RBD-dimer was first designed to adapt the resistant Beta variant. Compared with its homotypic forms, the chimeric vaccine elicited broader sera neutralization of variants and conferred better protection in mice. The protection of the chimeric vaccine was further verified in macaques. This approach was generalized to develop Delta-Omicron chimeric RBD-dimer to adapt the currently prevalent variants. Again, the chimeric vaccine elicited broader sera neutralization of SARS-CoV-2 variants and conferred better protection against challenge by either Delta or Omicron SARS-CoV-2 in mice. The chimeric approach is applicable for rapid updating of immunogens, and our data supported the use of variant-adapted multivalent vaccine against circulating and emerging variants.

Influence of Online Merging Offline Method on University Students' Active Learning Through Learning Satisfaction.

Students' active learning behavior determines learning performance. In post-COVID-19 period, Online Merging Offline (OMO) method become a common way of university students' learning. However, at present, there are few studies in active learning behavior in the OMO mode. Combined with learning satisfaction and Technology Acceptance Model (TAM), this paper proposes an Online Active Learning (OAL) Model to predict the influencing factors of college students' active learning behavior and then analyzes the differences between OMO model and pure online model by multi-group analysis (MGA) based on the model. The designed questionnaire was distributed, and a total of 498 valid questionnaires were collected. Using SmartPLS to analyze partial least squares structural equation modeling (PLS-SEM) and MGA, it is found that: (1) there are differences in the influencing factors of active learning between OMO and pure online model; the moderating effect of learning complaint in OMO mode is not established, and social isolation and age does not affect active learning in OMO mode; (2) learning quality, perceived ease of use, expectation, perceived usefulness, and social isolation indirectly affect active learning through learning satisfaction in both OMO model and pure online model; (3) learning satisfaction is an important mediating variable affecting active learning; and (4) learning complaints will negatively regulate the relationship between learning satisfaction and active learning only in pure online model. According to these findings, the paper provides theoretical and practical implementation suggestions implications for OMO teaching and OAL to ensure the expected learning outcome.

Do Playfulness and University Support Facilitate the Adoption of Online Education in a Crisis? COVID-19 as a Case Study Based on the Technology Acceptance Model

A large number of universities worldwide are paying more and more attention to the application and exploration of online education. As the group with the most significant number of online education users, their participation attitude and participation intention directly determine the teaching performance of online education. This research will incorporate playfulness teaching and scenario variables that reflect the universities’ ability to respond to emergencies. Based on the technology acceptance model, this research proposes an integrated research model of online education participation intention to investigate university students’ online education participation intention to reveal the key factors and mechanisms that affect online education participation intention. A structural equation model of participation intention is constructed, and 342 valid samples are obtained by questionnaire survey. The empirical results of PLS-SEM show that: (1) students’ participation attitude positively affects their participation intention;(2) the perceived ease of use and usefulness positively affect their participation attitude, and the perceived usefulness and ease of use affect their participation intention through the complete mediation of participation attitude;(3) the perceived playfulness does not have a significant impact on participation attitude but has a positive impact on participation intention;(4) the innovative discovery university support positively moderates the relationship between participation attitude and intention during such emergencies. The research found that improving students’ attitudes toward participation, perceived ease of use, usefulness, playfulness, and strengthening university support are all helpful to optimize students’ participation intention in online education. At the same time, it also explored operability suggestions for improving the quality of online education and optimizing future education.

Media exposure predicts acute stress and probable acute stress disorder during the early COVID-19 outbreak in China.

BACKGROUND: The COVID-19 has led to unprecedented psychological stress on the general public. However, the associations between media exposure to COVID-19 and acute stress responses have not been explored during the early COVID-19 outbreak in China. METHODS: An online survey was conducted to investigate the relationships between media exposure to COVID-19 and acute stress responses, and to recognize associated predictors of acute stress responses on a sample of 1,450 Chinese citizens from February 3 to February 10, 2020. Media exposure questionnaire related to COVID-19 was developed to assess media exposure time, media exposure forms and media exposure content. The Stanford Acute Stress Reaction Questionnaire (SASRQ) was used to measure acute stress responses, including continuous acute stress symptom scores and the risk of probable acute stress disorder (ASD). A series of regression analyses were conducted. RESULTS: Longer media exposure time and social media use were associated with higher acute stress and probable ASD. Viewing the situation of infected patients was associated with higher acute stress, whereas viewing the latest news about pandemic data was associated with lower odds of probable ASD. Being females, living in Hubei Province, someone close to them diagnosed with COVID-19, history of mental illness, recent adverse life events and previous collective trauma exposure were risk factors for acute stress responses. CONCLUSIONS: These findings confirmed the associations between indirect media exposure to pandemic events and acute stress responses. The governments should be aware of the negative impacts of disaster-related media exposure and implement appropriate interventions to promote psychological well-being following pandemic events.

A combined abiotic oxidation-precipitation process for rapid As removal from high-As(III)-Mn(II) acid mine drainage and low As-leaching solid products

A combination process of Fenton-like and catalytic Mn(II) oxidation via molecular oxygen-induced abio-oxidation of As(III)-Mn(II)-rich acid mine drainage (AMD) is developed to rapidly and efficiently remove As and obtain low As-leaching solids in this study. The effect of pH, temperature, oxygen flow rate and neutralization reagent on As removal was investigated. The results showed that pH was important to As removal efficiency, which achieved maximum in 0.25-2 h, but decreased from ∼100 % to ∼92.6 % with the increase of pH 5-9. pH, temperature and oxygen flow rate played key roles in As(III) oxidation. The increase of As(III) oxidized from 16.8 to 67.1% to 98.6-99.0 % occurred as increasing the pH 5-9, 25-95 °C and oxygen flow rate of 0-2.4 L min-1. NaOH or Ca(OH)2 as base was less important to As removal. The mechanism involved Fenton-like reaction between Fe(II) and O2 for produced Fe(III) (oxy)hydroxide association with As(III + V) and Mn(II), catalytic Mn(II) oxidation for the formation of Mn(III, IV) oxides, and further As(III) oxidation by Mn(III, IV) oxides. As-bearing six-line ferrihydrite was the main solid product for low As-leaching fixation. pH 8, 95 °C and oxygen flow rate of 1.6 L min-1 were optimal for As removal.