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Mathematics ; 11(5):1186, 2023.
Article in English | ProQuest Central | ID: covidwho-2254821


Exploring the hedging ability of precious metals through a novel perspective is crucial for better investment. This investigation applies the wavelet technique to study the complicated correlation between global economic policy uncertainty (GEPU) and the prices of precious metals. The empirical outcomes suggest that GEPU exerts positive influences on the prices of precious metals, indicating that precious metals could hedge against global economic policy uncertainty, which is supported by the inter-temporal capital asset pricing model (ICAPM). Among them, gold is better for long-term investment than silver, which is more suitable for the short run in recent years, while platinum's hedging ability is virtually non-existent after the global trade wars. Conversely, the positive influences from gold price on GEPU underline that the gold market plays a prospective role in the situation of economic policies worldwide, which does not exist in the silver market. Besides, the effects of platinum price on GEPU change from positive to negative, suggesting that the underlying cause of its forward-looking effect on GEPU alters from the investment value to the industrial one. In the context of the increasing instability of global economic policies, the above conclusions could offer significant lessons to both investors and governments.

researchsquare; 2022.


The ongoing coronavirus disease pandemic has fostered major advances in vaccination technologies; however, there are urgent needs of mucosal immune responses and single-dose, non-invasive administration. Here, we develop a SARS-CoV-2 vaccine for single-dose, dry-powder aerosol inhalation that induces potent systemic and mucosal immune responses. Our vaccine encapsulates proteinaceous cholera toxin B subunit-assembled nanoparticles displaying the SARS-CoV-2 RBD antigen (R-CNP) within microcapsules of optimal aerodynamic size, and such unique nano-micro coupled structure supports efficient alveoli delivery, sustained R-CNP release, and antigen presenting cell uptake, which are favorable for invocation of immune responses. Moreover, our vaccine successfully induces robust serological IgG and secretory IgA production, collectively conferring effective protection from SARS-CoV-2 challenge (including pseudovirus and the authentic virus) in mice, hamsters, and non-human primates. Finally, we also demonstrate a “mosaic iteration” of our vaccine that co-displays ancestral and Omicron’s antigens, thus extending the breadth of antibody response against co-circulating strains and transmission of Omicron variant. These findings support our inhalable vaccine as a promising candidate to prevent SARS-CoV-2 infection, disease, and transmission.

researchsquare; 2022.


Given that COVID-19 continues to wreak havoc around the world, it is imperative to search for a conserved region involved in viral infection so that effective vaccines can be developed to prevent the virus from rapid mutations. We have established a twelve-fragment library of recombinant proteins covering the entire region of spike protein of both SARS-CoV-2 and SARS-CoV from E. coli. IgGs from murine antisera specifically against six spike protein fragments of SARS-CoV-2 were produced, purified, and characterized. We found that one specific IgG against the fusion process region, named COVID19-SF5, serologically cross-reacted with all twelve S-protein fragments. COVID19-SF5, with amino acid sequences from 880 to 1084, specifically bound to VERO-E6 and BEAS-2B cells, with Kd values of 449.1 ± 21.41 and 381.9 ± 31.53 nM, and IC50 values of 761.2 ± 28.2 nM and 862.4 ± 32.1 nM, respectively. In addition, COVID19-SF5 greatly enhanced binding of the full-length CHO cell-derived spike protein to the host cells in a concentration-dependent manner. Furthermore, COVID19-SF5 and its IgGs inhibited the infection of the host cells by pseudovirus. The combined data from our studies reveal that COVID19-SF5, a novel cell-binding fragment, may contain a common region(s) for mediating viral binding during infection. Our studies also provide valuable insights into how virus variants may evade host immune recognition. Significantly, the observation that the IgGs against COVID19-SF5 possesses a cross-reactivity to all other fragments of S protein suggests that it is possible to develop universal neutralizing monoclonal antibodies to curb rapid mutations of COVID-19. 

Emerging Markets, Finance & Trade ; 56(15):3588-3598, 2020.
Article in English | ProQuest Central | ID: covidwho-977303


COVID-19 has had a worldwide impact. The consensus is that the sudden pause of global production and the shrinking international trade will contract the global economy. This study explores the short-term impact of the COVID-19 shock on global value chains (GVC), especially considering China’s production-capacity damage. Findings suggest that downstream countries and sectors suffer more from China’s production disruption than upstream ones. The Most impacted countries are the United States, South Korea, Japan, and Germany;while the most-affected sectors include electronic and optical equipment, textiles, machinery, manufacturing, and wholesale trade. It is found that China is too important in GVC to be substituted for in the current world economy.

biorxiv; 2020.
Preprint in English | bioRxiv | ID: ppzbmed-10.1101.2020.07.15.205211


The COVID-19 pandemic has taken a significant toll on people worldwide, and there are currently no specific antivirus drugs or vaccines. We report herein a therapeutic based on catalase, an antioxidant enzyme that can effectively breakdown hydrogen peroxide and minimize the downstream reactive oxygen species, which are excessively produced resulting from the infection and inflammatory process. Catalase assists to regulate production of cytokines, protect oxidative injury, and repress replication of SARS-CoV-2, as demonstrated in human leukocytes and alveolar epithelial cells, and rhesus macaques, without noticeable toxicity. Such a therapeutic can be readily manufactured at low cost as a potential treatment for COVID-19.