Objective To optimize the hemodynamics of a disk blood pump in children. Method We used the computational fluid dynamics technology to simulate the flow in a pediatric blood pump numerically, and finally analyzed the results for deep study about the thrombosis and hemolysis produced in it, to improve the design according to the results of the flow field analysis. Results We calculated results between the flow rate and the pressure elevation at different rotational speed: 2 500 rpm, 3 000 rpm, and 4 000 rpm, respectively. Under each rotational speed, it was selected five different discharge outlet boundary conditions. The simulation results conformed to the experimental data. The increased pressure of the blood pump was effective. But the phenomenon of flow separation was increased the at blade surface in the low speed region. The maximum wall shear stress was maintained within 100 Pa. Conclusion The design of disc blood pump has a good fluid dynamic performance. And the flow line is fluent, the probability of thrombosis and hemolysis occurred is in the range of control. But the phenomenon of flow separation is appeared. There is a room to improve.
The purpose of this paper is to report the research and design of control system of magnetic coupling centrifugal blood pump in our laboratory, and to briefly describe the structure of the magnetic coupling centrifugal blood pump and principles of the body circulation model. The performance of blood pump is not only related to materials and structure, but also depends on the control algorithm. We studied the algorithm about motor current double-loop control for brushless DC motor. In order to make the algorithm adjust parameter change in different situations, we used the self-tuning fuzzy PI control algorithm and gave the details about how to design fuzzy rules. We mainly used Matlab Simulink to simulate the motor control system to test the performance of algorithm, and briefly introduced how to implement these algorithms in hardware system. Finally, by building the platform and conducting experiments, we proved that self-tuning fuzzy PI control algorithm could greatly improve both dynamic and static performance of blood pump and make the motor speed and the blood pump flow stable and adjustable.
ObjectiveTo reveal the true value of plasma detection of epidermal growth factor receptor (EGFR) mutation for early-stage non-small cell lung cancer (NSCLC) gene diagnosis and to predict survival prognosis. MethodsTissue samples of positive EGFR mutations by using amplification refractory mutation system (ARMS) method were surgically resected from 198 patients with stage I-IV NSCLC between February 2014 and June 2015 in Tangdu hospital. Paired blood samples were collected before surgery. And the cellfree DNA (cfDNA) in plasma was extracted, plasma EGFR mutations were detected by real-time polymerase chain reaction (PCR). Concentration of cfDNA was measured by ultraviolet spectrophotometry. Follow-up observation for stage ⅢA patients was put into force after surgery. Kaplan-Meire was used in survival analysis. ResultsThe sensitivity of EGFR mutation for the 198 paired tissues and plasma samples was 17.2%.The sensitivity was positively correlated with TNM stage and negatively correlated with tumor differentiation. The sensitivity of sage ⅢA was 33.3%, significantly higher than that of the patients at stage ⅠA (1.6%, P=0.000) and stage ⅠB (7.9%, P=0.004). The sensitivity of poor differentiation was 36.8%, significantly higher than that of high differentiation (0.0%, P=0.000) and moderate differentiation (15.7%, P=0.010). There was no correlation between plasma cfDNA concentration and patient characteristics. Survival analysis showed that plasma detection was a vital factor for predicting postoperative survival prognosis of stage ⅢA patients (P=0.014). ConclusionTissue samples cannot be replaced by plasma samples for epidermal growth factor receptor (EGFR) mutation test in early-stage NSCLC patients, currently. When the sensitivity increases dramatically in the plasma samples of stage ⅢA NSCLC and poor differentiation tumor, we recommend using plasma detection for gene diagnosis, dynamic monitoring of EGFR mutations in stage ⅢA or poorly differentiated tumors, especially in NSCLC patients whose tissue samples cannot be obtained by surgery. And plasma EGFR detection is a valuable method of forecasting survival prognosis for locally advanced NSCLC patients.