To investigate the diagnostic value of serological testing and dynamic variance of serum antibody in coronavirus disease 2019 . Methods: This study retrospectively included 43 patients with a laboratory-confirmed infection and 33 patients with a suspected infection, in whom the disease was eventually excluded. The IgM/IgG titer of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was measured by chemiluminescence immunoassay analysis. Results: Compared to molecular detection, the sensitivities of serum IgM and IgG antibodies to diagnose COVID-19 were 48.1% and 88.9%, and the specificities were 100% and 90.9%, respectively.In the COVID-19 group, the IgM-positive rate increased slightly at first and then decreased over time; in contrast, the IgGpositive rate increased to 100% and was higher than IgM at all times. The IgM-positive rate and titer were not significantly different before and after conversion to virus-negative. The IgG-positive rate was up to 90% and not significantly different before and after conversion to virus-negative. However, the median IgG titer after conversion to virus-negative was double that before, and the difference was significant. Conclusions: Viral serological testing is an effective means of diagnosis for SARS-CoV-2 infection. The positive rate and titer variance of IgG are higher than those of IgM in COVID-19.

The polar-orbiting spherical experimental satellite of China for atmospheric density detection with an altitude of ~520 km was successfully launched on 14 October 2021. Based on the dynamic inversion method for atmospheric density and the precise orbit determination data obtained by its GNSS, we inverted the orbital atmospheric density during the severe geomagnetic storm in early November 2021. In this paper, we compared the atmospheric density data obtained by the spherical satellite with the simulations of the MSISE00 and the DTM, evaluated their error distribution, and analyzed the response of the atmospheric density during the severe geomagnetic storm in the dawn–dusk orbit of 520 km altitude. The properties and the physical processes for the atmospheric density of the time evolutions in different latitudes and the global distributions during the severe geomagnetic storm were obtained. We found that the substantial disturbance enhancement and recovery of the atmospheric density of the dawn–dusk orbit have a close correlation with the geomagnetic indexes Kp and Dst. The elevation extends from the poles to the equator, and the relative variation in two hemispheres demonstrates a bimodal nearly symmetric growth structure. The maximum relative variation of the two hemispheres both occurred in the middle latitude, and, for this case, the enhancement of atmospheric density in the mid-latitude region accounted for a larger proportion. The asymmetry between the northern and southern hemispheres is demonstrated by the fact that the absolute value and absolute change in the southern hemisphere in summer are larger than those in the northern hemisphere, and the bimodal structure of the relative variation is inclined to the northern hemisphere.

Background Since the Coronavirus Disease 2019 (COVID-19) was first identified in Wuhan, China, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pathogen, the disease has been found in many countries. Considering the lack of effective drugs and rapid spread of COVID-19, we did a clinical detailed retrospective analysis of 70 discharged patients which can help us to better determine the clinical features of the disease. Method We collected demographic, epidemiological, clinical, laboratory, and chest computed tomographic (CT) data from patients’ hospital records, the time period were from hospitalization day1 to day7 and hospitalization last day. The retrospective study totally included 70 COVID-19 patients. Results The median age was 43 (IQR: 34-56) years. 41 (58.6%) patients were female, and there were 33 (47.1%) patients who were hospitalized more than 14 days. 18 (25.7%) patients were residents of Wuhan or recently travelled to Wuhan, 38 (54.3%) patients were having a close contact with the COVID-19 patients. The most common pre-existing diseases were liver disease (15.7%), hypertension (12.9%), renal disease (8.6), lung disease (5.7%). The time from illness onset to hospitalization was 4 (IQR: 2-7) days. The most common treatment regimen was Lopinavir/ritonavir (LPV) + Interferon alpha inhalation (IAI) + Arbidol. Compared with hospitalization day1, White blood cell count, C-reacting protein, Potassium, Aspartate aminotransferase, Lactate dehydrogenase, and Lactic acid were significantly different than hospitalization day-last. The median number of times a patients receiving chest computed tomography (CT) from day1 to day7 was 3 (IQR: 3-4). The typical chest computed tomographic images were patchy shadows and ground glass opacity. Conclusion Currently, there are no specific antiviral therapies for COVID-19. 70 COVID-19 patients in our study responded positively to treatment during the two-week period. For those discharged patients with abnormal results, more attention is needed in the future studies to control the transmission.