RESUMO
As the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a grave threat to human life and health, it is essential to develop an efficient and sensitive detection method to identify infected individuals. This study described an electrode platform immunosensor to detect SARS-CoV-2-specific spike receptor-binding domain (RBD) protein based on a bare gold electrode modified with Ag-rGO nanocomposites and the biotin-streptavidin interaction system. The Ag-rGO nanocomposites was obtained by chemical synthesis and characterized by electrochemistry and scanning electron microscope (SEM). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to record the electrochemical signals in the electrode modification. The differential pulse voltammetry (DPV) results showed that the limit of detection (LOD) of the immunosensor was 7.2 fg mL−1 and the linear dynamic detection range was 0.015 ~ 158.5 pg mL−1. Furthermore, this sensitive immunosensor accurately detected RBD in artificial saliva with favorable stability, specificity, and reproducibility, indicating that it has the potential to be used as a practical method for the detection of SARS-CoV-2. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
RESUMO
The COVID-19 pandemic, and its management, is markedly impacting the management of osteoporosis as judged by access to online FRAX fracture risk assessments. Globally, access was 58% lower in April than in February 2020. Strategies to improve osteoporosis care, with greater use of fracture risk assessments, offer a partial solution. INTRODUCTION: The COVID-19 pandemic is having a significant detrimental impact on the management of chronic diseases including osteoporosis. We have quantified the global impact by examining changes in the usage of online FRAX fracture risk assessments before and after the declaration of the pandemic (11 March 2020). METHODS: The study comprised a retrospective analysis using GoogleAnalytics data on daily sessions on the FRAX® website ( www.sheffield.ac.uk/FRAX ) from November 2019 to April 2020 (main analysis period February-April 2020), and the geographical source of that activity. RESULTS: Over February-April 2020, the FRAX website recorded 460,495 sessions from 184 countries, with 210,656 sessions in February alone. In March and April, the number of sessions fell by 23.1% and 58.3% respectively, a pattern not observed over the same period in 2019. There were smaller reductions in Asia than elsewhere, partly related to earlier and less-marked nadirs in some countries (China, Taiwan, Hong Kong, South Korea and Vietnam). In Europe, the majority of countries (24/31, 77.4%) reduced usage by at least 50% in April. Seven countries showed smaller reductions (range - 2.85 to - 44.1%) including Poland, Slovakia, Czech Republic, Germany, Norway, Sweden and Finland. There was no significant relationship between the reduction in FRAX usage and measures of disease burden such as COVID-attributed deaths per million of the population. CONCLUSION: This study documents a marked global impact of the COVID-19 pandemic on the management of osteoporosis as reflected by FRAX online fracture risk assessments. The analysis suggests that impact may relate to the societal and healthcare measures taken to ameliorate the pandemic.