Background In December 2019, a pneumonia caused by a novel coronavirus (SARS-CoV-2) emerged in Wuhan, China and has rapidly spread around the world since then. Aim This study aims to understand the research gaps related to COVID-19 and propose recommendations for future research. Methods We undertook a scoping review of COVID-19, comprehensively searching databases and other sources to identify literature on COVID-19 between 1 December 2019 and 6 February 2020. We analysed the sources, publication date, type and topic of the retrieved articles/studies. Results We included 249 articles in this scoping review. More than half (59.0%) were conducted in China. Guidance/guidelines and consensuses statements (n = 56; 22.5%) were the most common. Most (n = 192; 77.1%) articles were published in peer-reviewed journals, 35 (14.1%) on preprint servers and 22 (8.8%) posted online. Ten genetic studies (4.0%) focused on the origin of SARS-CoV-2 while the topics of molecular studies varied. Nine of 22 epidemiological studies focused on estimating the basic reproduction number of COVID-19 infection (R0). Of all identified guidance/guidelines (n = 35), only ten fulfilled the strict principles of evidence-based practice. The number of articles published per day increased rapidly until the end of January. Conclusion The number of articles on COVID-19 steadily increased before 6 February 2020. However, they lack diversity and are almost non-existent in some study fields, such as clinical research. The findings suggest that evidence for the development of clinical practice guidelines and public health policies will be improved when more results from clinical research becomes available.

Nickel oxide nanoparticles (Nano NiO) bears hepatotoxicity, while whether it leads to liver fibrosis remains unclear. The aim of this study was to establish the Nano NiO‐induced hepatic fibrosis model in vivo and investigate the roles of transforming growth factor β1 (TGF‐β1) in Smad pathway activation, epithelial‐mesenchymal transition (EMT) occurrence, and extracellular matrix (ECM) deposition in vitro. Male Wistar rats were exposed to 0.015, 0.06, and 0.24 mg/kg Nano NiO by intratracheal instilling twice a week for 9 weeks. HepG2 cells were treated with 100 μg/mL Nano NiO and TGF‐β1 inhibitor (SB431542) to explore the mechanism of collagen formation. Results of Masson staining as well as the elevated levels of type I collagen (Col‐I) and Col‐III suggested that Nano NiO resulted in hepatic fibrosis in rats. Furthermore, Nano NiO increased the protein expression of TGF‐β1, p‐Smad2, p‐Smad3, alpha‐smooth muscle actin (α‐SMA), matrix metalloproteinase9 (MMP9), and tissue inhibitors of metalloproteinase1 (TIMP1), while decreased the protein content of E‐cadherin and Smad7 in rat liver and HepG2 cells. Most importantly, Nano NiO‐triggered the abnormal expression of the abovementioned proteins were all alleviated by co‐treatment with SB431542, implying that TGF‐β1‐mediated Smad pathway, EMT and MMP9/TIMP1 imbalance were involved in overproduction of collagen in HepG2 cells. In conclusion, these findings indicated that Nano NiO induced hepatic fibrosis via TGF‐β1‐mediated Smad pathway activation, EMT occurrence, and ECM deposition.

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Background: The outbreak of the coronavirus disease 2019 (COVID-19) has had a massive impact on the whole world. Computed tomography (CT) has been widely used in the diagnosis of this novel pneumonia.This study aims to understand the role of CT for the diagnosis and the main imaging manifestations of patients with COVID-19.Methods: We conducted a rapid review and meta-analysis on studies about the use of chest CT for the diagnosis of COVID-19. We comprehensively searched databases and preprint servers on chest CT for patients with COVID-19 between 1 January 2020 and 31 March 2020. The primary outcome was the sensitivity of chest CT imaging. We also conducted subgroup analyses and evaluated the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.Results: A total of 103 studies with 5,673 patients were included. Using reverse transcription polymerase chain reaction (RT-PCR) results as reference, a meta-analysis based on 64 studies estimated the sensitivity of chest CT imaging in COVID-19 was 99% (95% CI, 0.97-1.00). If case reports were excluded, the sensitivity in case series was 96% (95% CI, 0.93-0.99). The sensitivity of CT scan in confirmed patients under 18 years old was only 66% (95% CI, 0.15-1.00). The most common imaging manifestation was ground-glass opacities (GGO) which was found in 75% (95% CI, 0.68-0.82) of the patients. The pooled probability of bilateral involvement was 84% (95% CI, 0.81-0.88). The most commonly involved lobes were the right lower lobe (84%, 95% CI, 0.78-0.90) and left lower lobe (81%, 95% CI, 0.74-0.87). The quality of evidence was low