Molecular epidemiology of the first wave of severe acute respiratory syndrome coronavirus 2 infection in Thailand in 2020
SCIENTIFIC REPORTS
Authors: Puenpa, Jiratchaya; Suwannakarn, Kamol; Chansaenroj, Jira; Nilyanimit, Pornjarim; Yorsaeng, Ritthideach; Auphimai, Chompoonut; Kitphati, Rungrueng; Mungaomklang, Anek; Kongklieng, Amornmas; Chirathaworn, Chintana; Wanlapakorn, Nasamon; Poovorawan, Yong
Abstract
The coronavirus disease 2019 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a major global concern. Several SARS-CoV-2 gene mutations have been reported. In the current study associations between SARS-CoV-2 gene variation and exposure history during the first wave of the outbreak in Thailand between January and May 2020 were investigated. Forty samples were collected at different time points during the outbreak, and parts of the SARS-CoV-2 genome sequence were used to assess genomic variation patterns. The phylogenetics of the 40 samples were clustered into L, GH, GR, O and T types. T types were predominant in Bangkok during the first local outbreak centered at a boxing stadium and entertainment venues in March 2020. Imported cases were infected with various types, including L, GH, GR and O. In southern Thailand introductions of different genotypes were identified at different times. No clinical parameters were significantly associated with differences in genotype. The results indicated local transmission (type T, Spike protein (A829T)) and imported cases (types L, GH, GR and O) during the first wave in Thailand. Genetic and epidemiological data may contribute to national policy formulation, transmission tracking and the implementation of measures to control viral spread.
Nafion-Endowed Graphene Super-Anticorrosion Performance
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
Authors: Ding, Jiheng; Liu, Panlin; Zhou, Min; Yu, Haibin
Abstract
Application of graphene (Gr)-reinforced green waterborne epoxy (WEP) coatings faces two major challenges: one is the usage of hydrophilic dispersants that can weaken the interactions between emulsifiers/WEP, resulting in demulsification of the WEP matrix, and the other is the "corrosion promotion activity (CPA)" originated from the high electric conductivity of Gr itself, which restricts the long-term anticorrosion capability. Herein, effective electrostatic-driven exfoliation of graphite into few-layer functionalized Gr nanosheets (nGNSs) was achieved, in which the strong interaction between Nafion (NA) and graphite caused a high yield of 65% under liquid sonication. Due to the surface-protective function of NA, the as-exfoliated nGNSs exhibited good electrical insulation and self-assemble parallelly in the WEP matrix. Electrochemical results confirmed that the nGNSs/WEP coatings displayed extraordinary and durable corrosion protection for carbon steel substrates. With the addition of only 0.3 wt % nGNSs, the corrosion rate of the WEP coatings reduced by 450 times after 120 days of immersion in 3.5 wt % NaCl(aq). Furthermore, scratch experiments clearly verified that the reduced graphene oxide (rGO) had a typical CPA effect but the nGNSs did not. All of these results suggested that the nGNSs provide an appealing approach toward the preparation and application of graphene-based coatings, with great implications for high-performance anticorrosion of WEP coatings.