Indoor simulation training system for brain-controlled wheelchair based on steady-state visual evoked potentials / 生物医学工程学杂志

Brain-controlled wheelchair (BCW) is one of the important applications of brain-computer interface (BCI) technology. The present research shows that simulation control training is of great significance for the application of BCW. In order to improve the BCW control ability of users and promote the application of BCW under the condition of safety, this paper builds an indoor simulation training system based on the steady-state visual evoked potentials for BCW. The system includes visual stimulus paradigm design and implementation, electroencephalogram acquisition and processing, indoor simulation environment modeling, path planning, and simulation wheelchair control, etc. To test the performance of the system, a training experiment involving three kinds of indoor path-control tasks is designed and 10 subjects were recruited for the 5-day training experiment. By comparing the results before and after the training experiment, it was found that the average number of commands in Task 1, Task 2, and Task 3 decreased by 29.5%, 21.4%, and 25.4%, respectively ( < 0.001). And the average number of commands used by the subjects to complete all tasks decreased by 25.4% ( < 0.001). The experimental results show that the training of subjects through the indoor simulation training system built in this paper can improve their proficiency and efficiency of BCW control to a certain extent, which verifies the practicability of the system and provides an effective assistant method to promote the indoor application of BCW.

ASSESSMENT OF IRON BIOAVAILABILITY OF IRON BIOFORTIFIED MAIZE USING IN VITRO DIGESTION/CACO-2 CELL CULTURE MODEL / 营养学报

Objective To assess iron bioavailability of three iron-biofortified maizes using an in vitro digestion/ Caco-2 cell culture model. Method Three maize varieties rich in iron (Zhongtie 2, 3 and 4) and two maize varieties with lower content of iron (Zhengda 818 and 619) were pulverized, and the content of iron and phosphorus in each maize variety was measured. After digestion the iron bioavailability per g food was determined by using Caco-2 cell ferritin formation per mg cell protein as indicator. Results The iron content (33.250 mg/kg), iron bioavailability and the iron bioavailability per g food of Zhongtie 2 maize was the highest among all varieties, but its phosphorus content was lower. The maize varieties with the next higher iron bioavailability were Zhongtie 3 and Zhengda 818, and the lowest was Zhengda 619. Conclusion Zhongtie 2 maize contained the hightest content and bioavailability of iron,so it was optimal to use for the following human trials.