A Peptide-Based Magnetic Chemiluminescence Enzyme Immunoassay for Serological Diagnosis of Coronavirus Disease 2019.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel ß-coronavirus, causes severe pneumonia and has spread throughout the globe rapidly. The disease associated with SARS-CoV-2 infection is named coronavirus disease 2019 (COVID-19). To date, real-time reverse-transcription polymerase chain reaction (RT-PCR) is the only test able to confirm this infection. However, the accuracy of RT-PCR depends on several factors; variations in these factors might significantly lower the sensitivity of detection. METHODS: In this study, we developed a peptide-based luminescent immunoassay that detected immunoglobulin (Ig)G and IgM. The assay cutoff value was determined by evaluating the sera from healthy and infected patients for pathogens other than SARS-CoV-2. RESULTS: To evaluate assay performance, we detected IgG and IgM in the sera from confirmed patients. The positive rate of IgG and IgM was 71.4% and 57.2%, respectively. CONCLUSIONS: Therefore, combining our immunoassay with real-time RT-PCR might enhance the diagnostic accuracy of COVID-19.

An Internal-State-Variable-Based Continuous Dynamic Recrystallization Model for Thermally Deformed TC18 Alloy.

Continuous dynamic recrystallization (CDRX) is widely acknowledged to occur during hot forming and plays a significant role in microstructure development in alloys with moderate to high stacking fault energy. In this work, the flow stress and CDRX behaviors of the TC18 alloy subjected to hot deformation across a wide range of processing conditions are studied. It is observed that deformation leads to the formation of new low-angle grain boundaries (LAGBs). Subgrains rotate by absorbing dislocations, resulting in an increase in LAGB misorientation and the transition of some LAGBs into high-angle grain boundaries (HAGBs). The HAGBs migrate within the material, assimilating the (sub)grain boundaries. Subsequently, an internal state variable (ISV)-based CDRX model is developed, incorporating parameters such as the dislocation density, adiabatic temperature rise, subgrain rotation, LAGB area, HAGB area, and LAGB misorientation angle distribution. The values of the correlation coefficient (R), relative average absolute error (RAAE), and root-mean-square error (RMSE) between the anticipated true stress and measured stress are 0.989, 6.69%, and 4.78 MPa, respectively. The predicted outcomes demonstrate good agreement with experimental findings. The evolving trends of the subgrain boundary area under various conditions are quantitatively analyzed by assessing the changes in dynamic recovery (DRV)-eliminated dislocations and misorientation angles. Moreover, the ISV-based model accurately predicts the decreases in grain and crystallite sizes with higher strain rates and lower temperatures. The projected outcomes also indicate a transition from a stable and coarse-grained microstructure to a continuously recrystallized substructure.

The clinical and immunological features of pediatric COVID-19 patients in China.

In December 2019, the corona virus disease 2019 (COVID-19) caused by novel coronavirus (SARS-CoV-2) emerged in Wuhan, China and rapidly spread worldwide. Few information on clinical features and immunological profile of COVID-19 in paediatrics. The clinical features and treatment outcomes of twelve paediatric patients confirmed as COVID-19 were analyzed. The immunological features of children patients was investigated and compared with twenty adult patients. The median age was 14.5-years (range from 0.64 to 17), and six of the patients were male. The average incubation period was 8 days. Clinically, cough (9/12, 75%) and fever (7/12, 58.3%) were the most common symptoms. Four patients (33.3%) had diarrhea during the disease. As to the immune profile, children had higher amount of total T cell, CD8+ T cell and B cell but lower CRP levels than adults (P < 0.05). Ground-glass opacity (GGO) and local patchy shadowing were the typical radiological findings on chest CT scan. All patients received antiviral and symptomatic treatment and the symptom relieved in 3-4 days after admitted to hospital. The paediatric patients showed mild symptom but with longer incubation period. Children infected with SARS-CoV-2 had different immune profile with higher T cell amount and low inflammatory factors level, which might ascribed to the mild clinical symptom. We advise that nucleic acid test or examination of serum IgM/IgG antibodies against SARS-CoV-2 should be taken for children with exposure history regardless of clinical symptom.

Antibody responses to SARS-CoV-2 in patients with COVID-19.

We report acute antibody responses to SARS-CoV-2 in 285 patients with COVID-19. Within 19 days after symptom onset, 100% of patients tested positive for antiviral immunoglobulin-G (IgG). Seroconversion for IgG and IgM occurred simultaneously or sequentially. Both IgG and IgM titers plateaued within 6 days after seroconversion. Serological testing may be helpful for the diagnosis of suspected patients with negative RT-PCR results and for the identification of asymptomatic infections.

The natural history of chronic hepatitis B: a retrospective study.

OBJECTIVE: To clarify the natural history of chronic hepatitis B so as to evaluate its long-term therapeutic outcome of the patients and the efficacy of antiviral drugs. METHODS: A cohort of 183 biopsy-proven chronic hepatitis B patients (mean age of 31.75+/-8.03 years, male/female ratio: 152:31) and 247 controls were followed up retrospectively for 11.81+/-4.08 years. This study was focused on long-term clinical outcome including the rates of liver cirrhosis, hepatocellular carcinoma and death, apart from the long-term effect of antiviral drugs and prognostic factors. RESULTS: In the 183 chronic hepatitis B patients, 22 (12.02%) developed liver cirrhosis, 12 (6.56%) developed hepatocellular carcinoma, and 20 (10.93%) died. The 5-, 10- and 15-year survival rates were 97.27%, 91.62%, and 84.47%, respectively. The 5-, 10- and 15-year incidence rates of HCC were 0, 3.19%, and 11.56%, respectively. In the 247 controls, 6 (2.43%) died; none of them developed cirrhosis or HCC. The rates of death, liver cirrhosis, and HCC in the hepatitis B patients were markedly different (P<0.005) compared with the controls. The overall mortality of hepatitis B patients was 4.5-fold higher than the general population. Cox multiple regression analysis showed that old age, severe histological injury, and positive HBeAg were closely related to liver cirrhosis; old age, severe histological injury, and male were major factors leading to death. The independent variable of predicted HCC was not found. CONCLUSION: The long-term outcome of hepatitis B patients is poor and the efficacy of antiviral drugs needs further study.

[Long-term health-related quality of life in chronic hepatitis B patients].

OBJECTIVE: To evaluate their long-term outcome and the efficacy and economic significance of antiviral drugs by investigating the long-term health-related quality of life (HQL) in chronic hepatitis B (CHB) patients. METHODS: The HQL of 101 CHB patients with biopsy-proven 6 to 18 years ago and 105 persons of general population as control was studied with revised SF-36 questionnaire. RESULTS: The HQL in CHB patients was lower than that in general population in physical functioning, role physical, general health, mental health, and specific symptoms (mu > or = 2.10, P<0.05). CONCLUSIONS: The long-term HQL in chronic hepatitis B patients is poor.