Recently, the recurrence of positive SARS-CoV-2 viral RNA in recovered COVID-19 patients is receiving more attention. Herein we report a cohort study on the follow-up of 182 recovered patients under medical isolation observation. Twenty (10.99%) patients out of the 182 were detected to be SARS-CoV-2 RNA positive (re-positives), although none showed any clinical symptomatic recurrence, indicating that COVID-19 responds well to treatment. Patients aged under 18 years had higher re-positive rates than average, and none of the severely ill patients re-tested positive. There were no significant differences in sex between re-positives and non-re-positives. Notably, most of the re-positives turned negative in the following tests, and all of them carried antibodies against SARS-CoV-2. This indicates that they might not be infectious, although it is still important to perform regular SARS-CoV-2 RNA testing and follow-up for assessment of infectivity. The findings of this study provide information for improving the management of recovered patients, and for differentiating the follow-up of recovered patients with different risk levels. The current pneumonia epidemic (COVID-19), caused by the SARS-CoV-2 coronavirus has spread to more than 200 countries. There have been more than 8 million confirmed cases and up to 440,000 deaths (as of June 18, 2020) 1 , raising a high level of concern all over the world. Previous studies have mainly focused on the clinical and epidemiological characteristics of patients infected with SARS-CoV-2 2-4. With the increase in the number of recovered patients, follow-up and detection are particularly important. Previous studies have found that patients who have recovered from COVID-19 are still testing positive for SARS-CoV-2 5-7. A single center study reported that 7.41% of COVID-19 patients re-tested positive for SARS-CoV-2 RNA by real-time reverse transcriptase polymerase chain reaction (RT-PCR) test after discharge 8 , and this finding has challenged the current hospital discharge criteria for containing the pandemic. The present study analyzed the SARS-CoV-2 viral RNA test results in all 182 recovered COVID-19 patients in Shenzhen before April 21st during a 14-day medical isolation observation period, to provide more reference for containing the pandemic more effectively. Results Patients under 18 years old, and mild and moderately patients have a higher risk of re-testing positive. Among all the recovered and isolated patients, 182 of them satisfied the inclusion criteria of this study. They were all re-tested at least once. Eighty-four (46.2%) were males and 98 (53.8%) were females, and the average age was 46.4 ± 17.1 years (median 49 years, range 1-81 years). Thirty-nine (21.4%) had severe symptoms, and 143 (78.6%) had mild and moderate symptoms (Table 1). A few of them showed different symptoms (mild flu, allergic rhinitis, smoking-induced sore throat) during medical isolation, although COVID-19 symptoms did not recur. Twenty patients out of the 182 re-tested positive (13 females, seven m...

Recently, the recurrence of positive SARS-CoV-2 viral RNA in recovered COVID-19 patients get more attention. Here we report a cohort study on the follow up of 182 recovered patients under medical isolation observation. There are 20 (10.99 %) patients out of the 182 were detected SARS-CoV-2 RNA turned positive, but none of them shows any clinical symptomatic recurrence indicating that COVID-19 has a good prognosis. Females and young patients aged under 15 have higher re-positive rate than the average, and none of the severe patients turned re-positive. Notably, most of the re-positive cases turn negative in the followed tests, suggesting that the importance of dynamic surveillance of SARS-CoV-2 RNA for infectivity assessment.

Objective: The aim of this study was to observe the liver function recovery of COVID-19 patients after discharge. Patients and Methods: A total of 253 discharged COVID-19 patients in Shenzhen city, China were selected. The clinical characteristics of these patients were assessed. A 2-month follow-up and laboratory hematology test were performed to examine the status of patients' liver function. Results: Patients combined with liver diseases, especially fatty liver, are more likely to progress to severe condition (P<0.05). Patients in severe condition and those with liver diseases have higher rates of liver injuries during hospitalization, characterized by a significant increase in alanine aminotransferase (ALT) and aspartate aminotransferase (AST, P<0.01). The ALT, AST/ALT, gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), total protein (TP), albumin (ALB), and A/G levels showed significant differences in comparison with the control group (P<0.05, and P<0.001); and the outlier ratio of A/G, ALT, GGT and ALP of patients remained abnormal higher within 14 days after discharge (P<0.001). Liver injuries of COVID-19 patients may be related to the epidemiological characteristics, clinical indexes, basic diseases, symptoms, drug treatment during hospitalization and the complications. Indicators of liver function were correlated with cardiac function, renal function, thyroid function, lipid metabolism, glucose metabolism, immune index, leukocyte, erythrocyte, hemoglobin and platelet related indexes. The outlier ratio of TP, ALB and GLB remained extremely low throughout the follow-up period; the outlier ratio of ALT, AST and GGT decreased below 10% from a high level at 40 days after discharged. However, the outlier ratio of A/G, AST/ALT and ALP remained high during the follow-up period. Conclusions: Abnormal liver function might indicate worse recovery of COVID-19 patients. Changes in liver function should be emphasized during long-term follow-up of COVID-19 patients after hospital discharge; the necessity of employing appropriate interventions for liver function repair should be emphasized.

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In this study, Aqua-Moderate Resolution Imaging Spectroradiometer (MODIS) Collection (C6) and C6.1 Dark Target aerosol optical depth (AOD) retrievals at 3 km (DT3K) and 10 km (DT10K), Deep Blue AOD retrievals at 10 km (DB10K), and combined DT and DB (DTB) AOD retrievals at 10 km resolutions were validated from 2002 to 2014 against ground-based sunphotometer AOD measurements obtained from the Chinese aerosol remote sensing network (CARSNET). The CARSNET AOD data were obtained for sites at Mt. Waliguan (MW), Lanzhou (LZ), Ulate (UL), and Zhengzhou (ZZ) located in the Yellow River basin (YERB) region, China. Errors and agreement between satellite and ground data were reported using Pearson's correlation (R) and relative mean bias (RMB). Results showed that the DT3K C6.1 highest quality flag (QF = 3) AOD retrievals were well correlated with the sunphotometer AOD data, with an R of 0.82 and an RMB of 1.01. Overestimation and underestimation in DT AOD retrievals were observed for AOD > 1.1 and AOD < 1.1, respectively. A significant underestimation of 37% in DB10K AOD retrievals was observed across all the sites except ZZ, which was indicated by a low-value RMB (0.63). Spatial distribution maps showed high AOD values (>0.8) over the lower part of the YERB and low AOD values (<0.4) across the upstream part of the YERB. This might be due to a large number of aerosol emissions over the lower developed areas and a scarcity of aerosols over the upstream mountain areas. Overall, this study supports the use of DT10K C6.1 AOD retrievals over the western semi-arid and arid regions of the YERB and DTB10K AOD retrievals over the north-central water system and eastern plain regions of the YERB.Atmosphere 2019, 10, 426 2 of 18 climate-change assessment and air-quality monitoring, it is necessary and crucial to conduct long-term continuous aerosol observations at a regional scale [10][11][12][13].Scientists have made many efforts in establishing global and national aerosol observation networks for regular measurements of aerosol optical properties, such as the aerosol robotic network (AERONET) and the Chinese aerosol remote sensing network (CARSNET) [14]. These networks provide aerosol optical properties directly by using ground-based sunphotometers [15][16][17]. However, due to the high cost of construction and operation of ground-based sunphotometers, they are few in number at a global scale, especially in remote areas. Therefore, satellite remote sensing is expected to become an ideal technology for aerosol optical and radiation characteristic observations at regional and global levels. In recent decades, various satellite sensors including the Moderate Resolution Imaging Spectrometer (MODIS) have been used for regular aerosol monitoring [18][19][20].Recently, MODIS Collection (C6) aerosol products have been widely validated over land and ocean surfaces [21][22][23][24][25][26][27][28][29][30][31][32][33], including the Indian subcontinent [34][35][36], Southeast Asia [37], East Asia [38,39], Greece [40,41], and China [42][43][44]...

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With the outbreak and widespread of the COVID-19 pandemic, large numbers of disposable face masks (DFMs) were abandoned in the environment. This study first investigated the sorption and desorption behaviors of four antibiotics (tetracycline (TC), ciprofloxacin (CIP), sulfamethoxazole (SMX), and triclosan (TCS)) on DFMs in the freshwater and seawater. It was found that the antibiotics in the freshwater exhibited relatively higher sorption and desorption capacities on the DFMs than those in the seawater. Here the antibiotics sorption processes were greatly related to their zwitterion species while the effect of salinity on the sorption processes was negligible. However, the desorption processes were jointly dominated by solution pH and salinity, with greater desorption capacities at lower pH values and salinity. Interestingly, we found that the distribution coefficient ( K d ) of TCS (0.3947 L/g) and SMX (0.0399 L/g) on DFMs was higher than those on some microplastics in freshwater systems. The sorption affinity of the antibiotics onto the DFMs followed the order of TCS > SMX > CIP > TC, which was positively correlated with octanol-water partition coefficient (log K ow ) of the antibiotics. Besides, the sorption processes of the antibiotics onto the DFMs were mainly predominated by film diffusion and partitioning mechanism. Overall, hydrophobic interaction regulated the antibiotics sorption processes. These findings would help to evaluate the environmental behavior of DFMs and to provide the analytical framework of their role in the transport of other pollutants.