The recent outbreak of human infections caused by SARS-CoV-2, the third zoonotic coronavirus has raised great public health concern globally. Rapid and accurate diagnosis of this novel pathogen posts great challenges not only clinically but also technologically. Metagenomic next-generation sequencing (mNGS) and reverse-transcription PCR (RT-PCR) have been the most commonly used molecular methodologies. However, each has their own limitations. In this study, we developed an isothermal, CRISPR-based diagnostic for COVID-19 with near single-copy sensitivity. The diagnostic performances of all three technology platforms were also compared. Our study aimed to provide more insights into the molecular detection of SARS-CoV-2, and also to present a novel diagnostic option for this new emerging virus.
Abstract. Intense new particle formation (NPF) events were observed in the coastal atmosphere
during algae growth and farming season at Xiangshan gulf of the east China coast. High
nucleation-mode iodine concentrations measured by ultra-performance liquid chromatography
coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) confirmed that
the NPF events were induced by iodine species. Our study provides important information
on iodine speciation, size distributions, and its role in NPF in the context of heavy air
pollution in China's coastal areas. For the first time, we identified 5 inorganic iodine
species, 45 organic iodine compounds (35 molecular formulas), and a group of
iodide–organic adducts in aerosols. The concentrations and size distributions of iodine
species down to 10 nm were measured during the iodine-induced NPF, continental NPF, and
non-NPF days at the coastal site and compared to those at an inland site. The iodine in
the above four aerosol sample types were characterized by iodate, aromatic iodine
compounds, iodoacetic acid or iodopropenoic acid, and iodide–organic adducts,
respectively. Iodide and organic iodine compounds were found in the nucleation-mode
particles; however, it is still not clear whether they contributed to nucleation or just
new particle growth. Wild algae, as well as farmed algae, could be an important NPF
source in China's coastal areas.
Background 35 The recent outbreak of infections by the 2019 novel coronavirus (2019-nCoV), the third 36 zoonotic CoV has raised great public health concern. The demand for rapid and accurate 37 diagnosis of this novel pathogen brought significant clinical and technological challenges. 38 Currently, metagenomic next-generation sequencing (mNGS) and reverse-transcription PCR 39 (RT-PCR) are the most widely used molecular diagnostics for 2019-nCoV.40 Methods 41 2019-nCoV infections were confirmed in 52 specimens by mNGS. Genomic information was 42 analyzed and used for the design and development of an isothermal, CRISPR-based 43 diagnostic for the novel virus. The diagnostic performance of CRISPR-nCoV was assessed 44 and also compared across three technology platforms (mNGS, RT-PCR and CRISPR) 45 Results 46 2019-nCoVs sequenced in our study were conserved with the Wuhan strain, and shared 47 certain genetic similarity with SARS-CoV. A high degree of variation in the level of viral 48 All rights reserved. No reuse allowed without permission.the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The reduced human activities and associated decreases in aerosol emissions during the COVID-19 pandemic are expected to affect climate. Assuming emission changes during lockdown, back-to-work and post-lockdown stages of COVID-19, climate model simulations show a surface warming over continental regions of the Northern Hemisphere. In January-March, there was an anomalous warming of 0.05-0.15 K in eastern China, and the surface temperature increase was 0.04-0.07 K in Europe, eastern United States, and South Asia in March-May. The longer the emission reductions undergo, the warmer the climate would become. The emission reductions explain the observed temperature increases of 10-40% over eastern China relative to 2019. A southward shift of the ITCZ is also seen in the simulations. This study provides an insight into the impact of COVID-19 pandemic on global and regional climate and implications for immediate actions to mitigate fast global warming.
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