Despite the increasing use of copper in C-H functionalizations, the Cu-catalyzed direct deuteration of C-H bonds remains a significant challenge due to its inherent low reactivity in inverse C-H bond reconstruction. In this paper, a novel strategy had been developed to reverse the copper-catalyzed concerted metalation-deprotonation process by inhibiting the unexpected disproportionation of Cu(II) to Cu(III). Picolinic acid was identified as a powerful ligand for facilitating this H/D exchange with DO as deuterium source, and its inhibition activity was supported by preliminary control experiments and DFT studies.
View Article and Find Full Text PDFCOVID-19 transmission models have conferred great value in informing public health understanding, planning, and response. However, the pandemic also demonstrated the infeasibility of basing public health decision-making on transmission models with pre-set assumptions. No matter how favourably evidenced when built, a model with fixed assumptions is challenged by numerous factors that are difficult to predict.
View Article and Find Full Text PDFBackground: The use of social media data provides an opportunity to complement traditional influenza and COVID-19 surveillance methods for the detection and control of outbreaks and informing public health interventions.
Objective: The first aim of this study is to investigate the degree to which Twitter users disclose health experiences related to influenza and COVID-19 that could be indicative of recent plausible influenza cases or symptomatic COVID-19 infections. Second, we seek to use the Twitter datasets to train and evaluate the classification performance of Bidirectional Encoder Representations from Transformers (BERT) and variant language models in the context of influenza and COVID-19 infection detection.
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