In the present study, the performance of the liquid nitrogen frozen and thinned bovine pericardium was studied and compared with the porcine pericardium. The microstructure and mechanical properties of the bovine pericardium were observed and tested by hematoxylin-eosin (HE) staining and tensile test respectively. In all conditions, porcine pericardium was selected as a control group. The results showed that there was little difference in the performance of bovine pericardium after being frozen by liquid nitrogen. The secant modulus and ultimate strength of the thinned bovine pericardium were similar to those of porcine pericardium, however, the elastic modulus was a little higher than porcine pericardium. The study suggested that the performance of the thinned bovine pericardium was similar to those of porcine pericardium. It was easy for the thinned bovine pericardium to obtain a relatively ideal thickness and expected performance, therefore, the thinned bovine pericardium can be used as the materials of transcatheter aortic valve leaflets.
ObjectiveTo explore the epidemiological characteristics, clinical manifestations, laboratory examination and imaging findings of patients with coronavirus disease 2019 (COVID-19) outside Hubei Province in 2019.MethodsFrom January 21, 2020 to February 18, 2020, 17 patients with COVID-19 diagnosed by SARS-CoV-2 nucleic acid test in Xianyang Central Hospital of Shaanxi Province and 23 patients in Liaocheng Infectious Disease Hospital of Shandong Province were collected. The information of epidemiology, age, time of onset, first symptom, white blood cell, lymphocyte count, procalcitonin (PCT), serum amyloid protein A (SAA), C-reactive protein (CRP) and chest CT were collected and analyzed.Results40.0% of the 40 patients had a clear history of contact with Wuhan or other areas of Hubei, 60.0% had no clear exposure history, 60.0% were aggregative diseases, 40.0% were imported patients; the average visit time was (4.9±3.5) d, 35% of the patients had underlying diseases; 75.0% of the patients had fever, 7.5% of the initial symptoms were cough, 5.0% pharyngitis, 2.5% headache, and 10.0% were asymptomatic. In the laboratory examination, 77.5% of the patients' white blood cells were normal, 45.0% of the patients' lymphocyte count could be decreased, 72.5% and 55.0% of the patients' SAA and CRP increased respectively, 92.5% of the patients' PCT was normal, 92.5% of the patients were positive for the first nucleic acid test, and 72.5% of the patients' chest CT showed multiple ground glass lesions in one or both lungs, and the positive coincidence rate between the initial nucleic acid test and the chest CT test was 92.5%. 90% of the patients in the group were common type, and all patients were treated with aerosol inhalation of α-interferon combined with lopinavir/ritonavir tablets, 62.5% were treated with antibiotics and 15.0% were treated with glucocorticoid. All patients were improved and 14 patients were cured and discharged from hospital.ConclusionsSARS-COV-2 is highly contagious, family aggregation infection and asymptomatic infection may be the main mode of transmission outside Hubei Province, mild and common types are common, there are no specific changes in laboratory examination, and the condition is stable after treatment.