Understand Research Hotspots Surrounding COVID-19 and Other Coronavirus Infections Using Topic Modeling

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a virus that causes severe respiratory illness in humans, which results in global outbreak of novel coronavirus disease (COVID-19) currently. This study aimed to evaluate the characteristics of publications involving coronaviruses as well as COVID-19 by using topic modeling. MethodsWe extracted all abstracts and retained the most informative words from the COVID-19 Open Research Dataset, which contains 35,092 pieces of coronavirus related literature published up to March 20, 2020. Using Latent Dirichlet Allocation modeling, we trained a topic model from the corpus, analyzed the semantic relationships between topics and compared the topic distribution between COVID-19 and other CoV infections. ResultsEight topics emerged overall: clinical characterization, pathogenesis research, therapeutics research, epidemiological study, virus transmission, vaccines research, virus diagnostics, and viral genomics. It was observed that current COVID-19 research puts more emphasis on clinical characterization, epidemiological study, and virus transmission. In contrast, topics about diagnostics, therapeutics, vaccines, genomics and pathogenesis only account for less than 10% or even 4% of all the COVID-19 publications, much lower than those of other CoV infections. ConclusionsThese results identified knowledge gaps in the area of COVID-19 and offered directions for future research.

Magnetic resonance imaging of nude mice model injected in USPIO-PEG-sLeX in vivo / 实用放射学杂志

Objective To explore the value of the molecular probe USPIO-PEG-sLeX on nasopharyngeal carcinoma xenograft in nude mice.Methods The USPIO nanoparticles was synthesized by physical deposition method,and which was modified by PEG to synthesize USPIO-PEG-sLeX .The nude mice of nasopharyngeal carcinoma xenograft were divided into experimental and control groups.USPIO-PEG-sLeX and USPIO-PEG were injected into nude mice of experimental and control groups by caudal vein,respectively.MR T2 mapping imaging was scanned before and after the injection,and analyzed the changes of T2 values between experimental and control groups. Results USPIO-PEG-sLeX had a good representation.The non-enhanced T2 values between control and experimental group had no statistical significance (P >0.05).However,T2 values of the mice in two groups before and after injections were statistically significant (P <0.05);and T2 values of experimental group were much lower than that of the control group after the injection,additionally,the difference of enhanced rate between the two groups was statistically significant (P <0.05).Conclusion USPIO-PEG-sLeX magnetic nanoparticles is potential to be a targeted contrast agent to ELAM-1 expression of nasopharyngeal carcinoma,and can be valuable in non-invasive dynamic monitoring the expression of ELAM-1.