RESUMEN
BACKGROUND: We designed an exercise system in which the user is accompanied by a virtual partner (VP) and tested bodyweight squat performance with different interactive VP features to explore the comprehensive impact of these VP features on the individual's exercise level (EL) and exercise perception. METHODS: This experiment used three interactive features of VP, including body movement (BM), eye gaze (EG), and sports performance (SP), as independent variables, and the exercise level (EL), subjective exercise enjoyment, attitude toward the team formed with the VP, and local muscle fatigue degree of the exerciser as observational indicators. We designed a 2 (with or without VP's BM) × 2 (with or without VP's EG) × 2 (with or without VP's SP) within-participants factorial experiment. A total of 40 college students were invited to complete 320 groups of experiments. RESULTS: (1) Regarding EL, the main effects of BM and SP were significant (p < 0.001). The pairwise interaction effects of the three independent variables on EL were all significant (p < 0.05). (2) Regarding exercise perception, the main effects of BM (p < 0.001) and EG (p < 0.001) on subjective exercise enjoyment were significant. The main effect of BM on the attitude toward the sports team formed with the VP was significant (p < 0.001). The interaction effect of BM and SP on the attitude toward the sports team formed with the VP was significant (p < 0.001). (3) Regarding the degree of local muscle fatigue, the main effects of BM, EG, and SP and their interaction effects were not significant (p > 0.05). CONCLUSION: BM and EG from the VP elevate EL and exercise perception during squat exercises, while the VP with SP inhibited the EL and harmed exercise perception. The conclusions of this study can provide references to guide the interactive design of VP-accompanied exercise systems.
RESUMEN
Lead ions are heavy metal ions that are extremely harmful to the human body and ecological environment. They can cause irreversible damage to the human nervous system and blood system at low concentrations. It is very important to develop a simple, rapid, and sensitive detection method of Pb2+. Solution-gated graphene transistors (SGGTs) have been widely studied in recent years due to their ultra-high sensitivity in chemical sensing. Herein, we have demonstrated a sensitive sensor of Pb2+ based on the SGGTs through the glutathione gate modification. When Pb2+ are added into the electrolyte solution, the electrical double layer capacitance near the gate electrode changes because Pb2+ can be strongly chelated, leading to the channel current change. The detection of Pb2+ can be realized. The detection limit of sensors for Pb2+ can reach 1 × 10-18 M, and the response time is about 1 s. The channel current change and the logarithm of Pb2+ concentration exhibit a good linear relationship in the concentration range of 1 × 10-18 and 1 × 10-6 M. Because the glutathione molecule can well recognize Pb2+, the devices also demonstrate good selectivity to Pb2+. Compared with the convention detection, our method shows easy operation, high sensitivity, and high selectivity. Therefore, it has great potential in the analysis of trace samples for health and environment monitoring.
