Effects of flywheel resistance training on the running economy of young male well-trained distance runners.

The study aimed to investigate the effect of flywheel accentuated eccentric loading (AEL) training on the running economy (RE) of young male well-trained distance runners. Twenty-two runners participated and were randomly assigned to the flywheel (FG, n = 12) and the control group (CG, n = 10). Traditional endurance training was performed in both groups three times a week for 6-week, while traditional resistance and flywheel AEL training was added to the CG and FG respectively. Subjects performed the incremental exercise test, squat jump, and countermovement jump (CMJ) before and after training. The results showed that 1) the RE at 65% of peak oxygen consumption (VO2peak), 75% VO2peak, and 85% VO2peak improved significantly after 6 weeks of training (p < 0.01, Effect size (ES) = 0.76; p < 0.01, ES = 1.04; p < 0.01, ES = 1.85) in FG, and the RE of 85% VO2peak in FG was significantly lower than CG (p < 0.05, ES = 0.30); 2) in post-training, both squat jump (p < 0.01, ES = 0.73) and CMJ (p < 0.01, ES = 1.15) performance, eccentric utilization ratio (p < 0.04, ES = 0.44), the rate of force development (RFD) of squat jump (p < 0.05, ES = 0.46), and CMJRFD (p < 0.01, ES = 0.66) were significantly improved in FG. And there are no significant differents in CG group because it was maintain training for our participants. Our findings showed that 1) flywheel AEL training improves the muscles' explosive strength and other neuromuscular functions, and improves the athlete's running economy under 65%, 75%, and 85% VO2peak, which potentially increases endurance performance. 2) Flywheel AEL training can improve the height, RFD, and the eccentric utilization ratio of squat jump and CMJ, and other lower limb elastic potential energy indicators of the young male, well-trained distance runners.

In vivo CT imaging of gold nanoparticle-labeled exosomes in a myocardial infarction mouse model.

BACKGROUND: Acute myocardial infarction (MI) is the primary factor leading to cardiovascular diseases, which are the main causes of morbidity and mortality in developed countries. Mesenchymal stem cell (MSC)-derived exosomes have been reported to improve heart function after MI; however, the molecular mechanisms responsible for this are unknown. In vivo imaging can reveal the trafficking process and in vivo biodistribution of exosomes, which may provide an insight into the communication mechanisms and pharmacokinetics of exosomes. METHODS: Glucose modified gold nanoparticles were used to label MSC-derived exosomes, aimed at minimizing membrane damage and maintaining the integrity of the exosomes. After labeling, the exosomes were visualized by in vivo computed tomography (CT) imaging to determine the biodistribution at 4 and 24 h after injection into a MI mouse model. RESULTS: MSC-derived exosomes were successfully labeled by glucose modified gold nanoparticles and CT imaging of these labeled exosomes indicated that MSC-Exo remained in the MI area for up to 24 h after intramyocardial injection. Additionally, few MSC-Exo were observed in some other organs, particularly the liver, spleen, and kidney. CONCLUSIONS: A gentle method was used for loading GNPs into exosomes, and their successful labeling without causing aggregation was verified. In vivo CT imaging revealed the retention of MSC-Exo in the MI area, indicating their usefulness for improving heart function after infarction.

Adsorption of Pb(II) from aqueous solution by polyacrylic acid grafted magnetic chitosan nanocomposite.

A creative combination of chitosan with polyacrylic acid (PAA) improves the acidity resistance of chitosan and increases its potential in the field of adsorption. In order to facilitate recovery, magnetic nanoparticles were incorporated in CS-PAA to obtain a magnetic-CS-PAA (MCS-PAA) nanocomposite. The physical and chemical characteristics of the composite adsorbent MCS-PAA were determined by SEM, TEM, FTIR, EDX, XRD, and XPS. This environmental-friendly, magnetic, composite adsorbent showed significantly better adsorption performance than those of the individual adsorbents alone. The maximal adsorption capacity was 204.89 mg/g according to the Langmuir isotherm model, when the concentration of Pb(II) was 100 mg/L at the equilibrium time of 70 min. The main adsorption mechanism was the complexation between the carboxyl, amino, and hydroxyl groups in MCS-PAA and Pb(II). Further, introduction of PAA also improved the acid resistance of CS. The new adsorbent MCS-PAA is thus expected to facilitate a wider range of applications for chitosan in the adsorption of Pb(II).