ABSTRACT
To facilitate noninvasive diagnosis of anemia, high-performance and portable near infrared (NIR) spectrometer for human blood constituents was designed and fabricated based on linear variable filter (LVF).Meanwhile, the performance of support vector regression (SVR) model for quantitative analysis of human hemoglobin (Hb) was investigated.Spectral data were collected noninvasively from 100 volunteers by self-designed LVF-NIR spectrometer, then divided into calibration set, validation set 1 and 2.To establish a robust SVR model, grid search method was applied to optimize the penalty parameter and kernel function parameter c=5.28, g=0.33.Then, Hb levels in the validation 1 and 2 sets were quantitatively analyzed.The results showed that the root mean square error of prediction (RMSEP) were 10.20 g/L and 10.85 g/L, respectively, and the relative RMSEP (R-RMSEP) were 6.85% and 7.48%, respectively.The results indicated that the SVR model had high prediction accuracy to Hb level and adaptability to different samples, and could satisfy the requirements of clinical measurement.Based on the SVR algorithm, the self-designed LVF-NIR spectrometer has a wide application prospect in the field of non-invasive anemia diagnosis.
ABSTRACT
A portable device for long-term monitoring of oxygen uptake without discomfort has been developed based on a flow-through principle. The oxygen content of the exhaust gas was kept constant by a servo-controlled blower, so that the flow rate was essentially proportional to the oxygen uptake. This system was evaluated by both a bench test and in exercising human subjects. The limiting current-type oxygen sensor used this portable device produced results which were in good agreement those obtained using a zirconia oxygen sensor (r= 0.999), and stable values were obtained for at least 15 h. The response time for a stepped oxygen change was 4 s. The air flow rate produced by the blower was proportional to the supplied voltage. The results using a time-of-flight flowmeter were highly correlated with those for a hot-wire anemometer (r=0, 999) . The oxygen uptake of exercising human subjects measured with this portable device showed good agreement with that obtained by a conventional oxygen monitor (r=0.973 for cycle ergometer, r=0, 932 for treadmill) . This portable device was able to measure oxygen uptake in subjects during daily activities, and also while driving a car, without disturbance.