Résumé
OBJECTIVE: To study the algorithm of four-parameter logistic regression and apply the model in the potency calibration of bacterial endotoxin standard. METHODS: The potency of endotoxin reference standard was estimated by a novel monocyte activation test,HL60-IL6 assay.The endotoxin national standard was set as standard, while the endotoxin working standard was set as test. The four-parameter logistic model was fitted by the method of nonlinear least squares when observations of standard or sample solutions were plotted against endotoxin concentration. The algorithm was performed by C Language, the RESULTS: of which were compared by those of softmax, R Language as well as Microsoft Office Excel. RESULTS The estimated parameters as well as estimated potency were parallel between the four statistical tools. The goodness-of-fit were all over 0.99.The variance was within 0.1%. CONCLUSION: The four-parameter logistic model can be established by the four statistical tools. Researchers can select a suitable tool according to demands.
Résumé
It is very important for pulmonary disease treatment to monitor the pulmonary function continuously. In this paper, the hardware of electrical impedance tomography (EIT) system is designed, and simulative model of human thorax is established for image reconstruction based on Landweber pre-iteration method. Compared with linear back projection, the method above results in the better image reconstruction with little trailing and increased speed of real-time reconstruction.