Background: Almost a year after the outbreak of coronavirus disease 2019 (COVID-19), many hospitalized COVID-19 patients have recovered. However, little is known about the long-term follow-up (> 2 months) of discharged patients. Methods: This study enrolled 527 discharged COVID-19 patients from 05 February to 11 March 2020. Basic characteristics, imaging features, nucleic acid detection results, and antibody levels of these patients were retrospectively reviewed. Results: Of the 527 discharged patients, 32 (6.1%) had re-detectable positive (RP) nucleic acid results for SARS-CoV-2 during follow-up examinations, with 11 and four detections entailing stool samples and anal swabs, respectively, rather than respiratory samples. Juveniles were more susceptible to "infection recurrence" than other age groups, with shorter time spans for re-detectable positive (RP) RNA tests (an average of 8.8 days [6.0-9.0 days]), while the reverse was true for the middle-aged group (17.5 days on average [14.0-17.5 days]). Similar improvements in the imaging features of both RP and no RP (NRP) groups were observed. Negative antibody detections in patients at 3 and 6 months after discharge were 14.2% and 25.0%, respectively. Cases evidencing negative antibodies were more common among juvenile patients (40% vs. 15.6%, P = 0.03) 6 months post-discharge. Conclusions: A total of 6.1% of 527 discharged patients showed RP status, which may be easier to be identified from stool samples than from other samples. Given the dropping rate of SARS-CoV-2 antibodies, reinfection may happen, especially in juvenile patients (aged < 18 years). These findings have implications for the long-term management of recovered COVID-19 patients.
Since the early march of 2020, higher education institutions around the world shut down quickly because of the outbreak of covid-19. This article addresses China’s response to this unprecedented pandemic in terms of a nationwide school closure. This article introduces how Chinese higher institutions use different strategies to launch online education under the initiative entitled “Ensuring Learning Undisrupted when Classes are Disrupted” from the Ministry of Education. The article also provides brief introduction on China’s online education initiative in a global context. Concerns of online education discussed in this article include equitable access to online education, challenges of curriculum design, and academic integrity. Practical suggestions are therefore offered based on North American experience. Finally, this article concludes the critical impact of online education on Chinese higher institutions during and even after this pandemic.
Purpose
The objective of this work is to characterize and quantify the impact of respiratory-induced prostate motion.
Methods and Materials
Real-time intrafraction motion is observed with the Calypso 4-dimensional nonradioactive electromagnetic tracking system (Calypso Medical Technologies, Inc. Seattle, Washington). We report the results from a total of 1024 fractions from 31 prostate cancer patients. Wavelet transform was used to decompose the signal to extract and isolate the respiratory-induced prostate motion from the total prostate displacement.
Results
Our results show that the average respiratory motion larger than 0.5 mm can be observed in 68% of the fractions. Fewer than 1% of the patients showed average respiratory motion of less than 0.2 mm, whereas 99% of the patients showed average respiratory-induced motion ranging between 0.2 and 2 mm. The maximum respiratory range of motion of 3 mm or greater was seen in only 25% of the fractions. In addition, about 2% patients showed anxiety, indicated by a breathing frequency above 24 times per minute.
Conclusions
Prostate motion is influenced by respiration in most fractions. Real-time intrafraction data are sensitive enough to measure the impact of respiration by use of wavelet decomposition methods. Although the average respiratory amplitude observed in this study is small, this technique provides a tool that can be useful if one moves to smaller treatment margins (≤5 mm). This also opens ups the possibility of being able to develop patient specific margins, knowing that prostate motion is not unpredictable.
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