ABSTRACT
Objective To investigate the plantar force characteristics during human walking and running under different gravity environment. Methods Seven healthy male volunteers walked and ran in vertical position on a weight-loss suspension treadmill under simulated Mars gravity (1/3 G) and lunar gravity (1/6 G), and traditional earth gravity (1 G) respectively at three different velocities (3, 7 and 10 km/h). During the exercise, parameters such as stance phase, plantar force, and gait balance in gait cycle were analyzed by using the F-scan insole pressure distribution measurement system. Results At the same velocity during a gait cycle, the contact phase was significantly shorter with the decrease of gravity, but the swing phase was significantly longer (P0.05). The peak and average plantar force, force integrity were significantly reduced with the decrease of gravity. Under normal gravity, the increase of velocity could lead to an obvious increase in peak and average plantar force and an obvious decrease in force integrity. While under simulated lunar and Mars gravity, no significant changes were found in plantar force (P>0.05). Under the three gravities, the ratio of vertical impact was quite different in between (P<0.05), but no significant difference was found in the phase symmetry index. Conclusions As compared to normal gravity environment, parameters benefiting for skeleton and muscle function such as plantar force and contact phase were found to be much smaller under low gravity environment, indicating the necessity of considering these factors when designing countermeasures or exercise prescriptions for space flight so as to sustain the astronaut’s normal function of skeleton and muscle.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the target deliver of Cisplatin to oral carcinoma tissues by intravenous injection of Cisplatin loaded polylactic acid- polyethylene glycol nanoparticles (CDDP-PLA-PEG-NP).</p><p><b>METHODS</b>CDDP-PLA-PEG-NP was prepared by the emulsion-solvent evaporation method. The buccal cancer model was established in 64 golden hamsters, which were divided randomly into two groups for 32 animals in each group, CDDP-PLA-PEG-NP (6.6 mg/kg) and CDDP (1 mg/kg) were respectively injected into mice tail vein. At 0.083, 0.5, 1, 2, 4, 6, 12, 24 h after drug administration. 4 animals in each group were sacrificed and CDDP concentration in the plasma and tumor were determined by high performance liquid chromatography. Targeting ability was evaluated by targeting index (TI), selectivity index (SI) and relative extraction efficiency (re).</p><p><b>RESULTS</b>The average diameter of CDDP-PLA-PEG-NP was (143.2 +/- 1.8) nm. The diameter distribution was from 103.5 nm to 175.8 nm. Drug loading and embedding ratio were (15.2 +/- 0.9) %, (89.0 +/- 0.8) % respectively. Values of TI and SI are more than 1 at 8 time points. The area under CDDP concentration-time curve of oral carcinoma tissues in CDDP-PLA-PEG-NP group was 10.36 times as many as that in CDDP group.</p><p><b>CONCLUSION</b>CDDP-PLA-PEG-NP can specifically deliver CDDP to oral carcinoma tissues by vein injection. Stealth anticancer nano-particle system can be regarded as a valuable drug deliver system to treat oral carcinoma.</p>