Objective:The hemolytic prediction model of the axial flow impeller blood pump is carried out by using a computational fluid dynamics(CFD) multiphase flow model.Methods:The hydrodynamic performance of the pump and the flow field in the pump, and the shear stress distribution are analyzed. A hemolytic prediction model based on the shear stress is built based on the calculation results. Hemolysis tests in vitro were performed 6 times with fresh bovine blood. At each time, the flow of the ventricular assist device(VAD) is 5 L/min and the outflow tract pressure is 100 mmHg(13.3kPa). According to the tests, the plasma free hemoglobin(FHB) content and the hematocrit(HCT) are measured every half hour. At the end of each experiment Normal Index of Hemolysis(NIH) is calculated.Results:The average of NIH is 0.0055 g/100L, almost identical with that obtained from the hemolytic prediction model.Conclusion:Multiphase flow model can be used for quantitative predictions of the hemolytic behavior of a VAD. This method can be applied in the selection stage of a blood pump.

Objective:To explore the epidemiological characteristics and the antibiotic resistance of Streptococcus pneumoniae isolates, and to provide the evidence for the rational use of antimicrobial agents to treat Streptococcus pneumoniae infection. Methods:The positive microbiological laboratory identification and antimicrobial susceptibility testing of Streptococcus pneumoniae from sputum of children with respiratory infections during January 2010 to December 2017 in Children′s Hospital of Soochow University were retrospectively analyzed. The positive rates of Streptococcus pneumoniae of different genders, ages, years and seasons were compared. The annual detection rates and trends of drug resistance of Streptococcus pneumoniae to penicillin, amoxicillin and cefotaxime were analyzed by Mann-Kendall trend test. The seasonal decomposition of time series was conducted to assess the association between Streptococcus pneumoniae detection rate and season. Enumeration data was compared using χ2 test. Results:Of the 88 480 sputum specimens, the total positive rate of Streptococcus pneumoniae was 10.3%(9 081/88 480). The detection rates of Streptococcus pneumoniae in children aged 0 to <0.5 years old, 0.5 to <2 years old, 2 to <3 years old, 3 to <5 years old, and 5 to <15 years old were 4.2%(1 407/33 224), 13.1%(3 191/24 390), 14.9%(2 417/16 252), 17.9%(1 474/8 246) and 9.3%(592/6 368), respectively. The difference was statistically significant ( χ2=2 421.6, P<0.01). The detection rates were 8.1%(1 321/16 306) from January to March, 10.9%(2 194/20 207) from April to June, 8.5%(2 141/25 058) from July to September, and 12.7%(3 425/26 909) from October to December. The discrepancy of positive rates in different seasons showed statistical significance ( χ2=311.5, P<0.01). During 2010 to 2017, significant decreases in antibiotic resistant rates of Streptococcus pneumoniae to penicillin, amoxicillin and cefotaxime were detected (tau=-0.93, -0.93 and -0.71, respectively, all P<0.05). Conclusions:The detection rate of Streptococcus pneumoniae in sputum of children with respiratory infections may present seasonal pattern and vary between different ages of children. The resistance to β-lactam antibiotics has declined.

Objective:To investigate the clinical efficacy of conservative and surgical treatment of testicular appendage torsion in children and to summarize the experience.Methods:The clinical data of 106 children with testicular appendage torsion admitted in Tengzhou Central People's Hospital Affiliated to Xuzhou Medical University from January 2012 to December 2018 were retrospectively analyzed. According to different therapeutic methods, all the children were divided into conservative group (25 cases) and surgical group (81 cases). The clinical efficacy was compared between the two groups.Results:106 children with testicular appendage torsion were cured. The hospitalization time [(5.61±1.04)d vs (11.32±1.89)d], pain relief time [(9.11±2.56)d vs (68.5±19.87)d], disappearance time of scrotal edema [(5.11±1.08)d vs (10.56±1.50)d] and the utility time of antibiotic [(4.89±1.32)d vs (7.06±1.26)d] in the surgical group were shorter than those in the conservative group, with statistically significant difference(all P<0.05). After 6 months of follow-up, there were no cases of recurrence and discomfort in the two groups. Conclusions:Children with testicular appendage torsion should be actively treated with surgery, which can not only significantly shorten the course of disease, but also reduce the incidence of complications and missed diagnosis. For children who with testicular appendage torsion, surgeries should be performed actively. It can significantly shorten the duration of symptoms, but also reduce the occurrence of complication and the occurrence probability of misdiagnosis.