(Mis)Information on Digital Platforms: Quantitative and Qualitative Analysis of Content From Twitter and Sina Weibo in the COVID-19 Pandemic.

Background: Misinformation about COVID-19 on social media has presented challenges to public health authorities during the pandemic. This paper leverages qualitative and quantitative content analysis on cross-platform, cross-national discourse and misinformation in the context of COVID-19. Specifically, we investigated COVID-19-related content on Twitter and Sina Weibo-the largest microblogging sites in the United States and China, respectively.

Quantitative relationship between the structures and properties of VOCs and SOA formation on the surfaces of acidic aerosol particles.

In this research, all the efforts, based on a series of molecular dynamics simulations on the interfacial process between VOC-contaminated air and acidic sulfate, were made to find how the structures and properties of VOCs are related to the formation of SOAs. The experimental fractional aerosol coefficients (FACs) were used to quantify the SOA formation and 14 VOC species were chosen based on the atmosphere inventory and the FAC magnitude. Finally, the quantitative relationship (QR) was found through the FAC as a function of the two variables the total valid interactions (Tg) and the diffusion coefficient (D), with R square 0.

New insights into the formation mechanism of gold nanoparticles using dopamine as a reducing agent.

Dopamine (DA), a simplified mimic of mussel proteins, can be employed as a reductant in the preparation of Au nanoparticles (AuNPs) due to its inherent catechol building block. The widely accepted mechanism of AuNP formation using DA as the reductant assumes that the reduction of Au(III) ions involves the two-electron oxidation of DA, where the corresponding phenol and phenolates serve as the reductive species to yield quinone. We herein report a novel insight into the mechanism of formation of AuNPs using DA as the reductant.

[Cerebrosides isolated from Arisaema flavum].

Silica gel, Sephadex LH-20, and reverse phase (C-18) column chromatography were used for the research of chemical constituents occurred in Arisaema flavum(Forsk.) Schott. The structures were elucidated by comparison physico-chemical properties and NMR spectroscopic data with those of known compounds.

Dereplication of known pregnane glycosides and structural characterization of novel pregnanes in Marsdenia tenacissima by high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry.

In the search for novel natural products in plants, particularly those with potential bioactivity, it is important to efficiently distinguish novel compounds from previously isolated, known compounds, a process known as dereplication. In this study, electrospray ionization-multiple stage tandem mass spectrometry (ESI-MS(n)) was used to study the behaviour of 12 pregnane glycosides and genins previously isolated from Marsdenia tenacissima, a traditional Chinese medicinal plant, as a basis for dereplication of compounds in a plant extract. In addition to [M + Na](+) and [M + NH(4)](+) ions, a characteristic [M-glycosyl + H](+) ion was observed in full-scan mode with in-source fragmentation.