Evaluation of Optimal Gravity Center Position of Backpack in Half-Squat Parachuting Landing / 医用生物力学

Objective To study effects of backpack gravity center position on kinetics and kinematics of lower-extremity joints in parachuting landing and evaluate the injuries. Methods Seven participants performed parachuting landing with backpack gravity center on three positions: low-back (position 1), upper-back (position 2) and abdomen (position 3). Results The peak vertical ground reaction force (GRF) with backpack on position 2 was significantly lower than that on position 1. The joint moment on sagittal plane of the hip with backpack on position 2 was significantly higher than that on position 1 and position 3. The joint energy absorption of the hip with backpack on position 2 was significantly higher than that on position 1. The angular displacement of the hip on sagittal plane with backpack on position 2 was significantly higher than that on position 1 and was significantly lower than that on position 3. The angular velocity of the hip on sagittal plane with backpack on position 2 was significantly lower than that on position 3. Conclusions Different positions of backpack gravity center could significantly influence kinetic and kinematic parameters of the hip. Backpack gravity center on upper-back position could decrease the lower-extremity injuries. The results can provide evidences for evaluating backpack gravity center and decreasing injuries in parachuting landing.

Research progress of small molecule active peptides in bone tissue engineering / 国际生物医学工程杂志

Although bone tissue has a certain ability of self-healing, bone transplantation is still needed for bone defects beyond the limit of self-healing. Calcium and phosphorus materials, such as hydroxyapatite and tricalcium phosphate, are currently common biological scaffold materials for bone repair, but these bioactive materials often lack osteoinductive activity, ability of promoting seed cell adhesion and angiogenesis. The traditional method to remedy these defects is to use growth regulators such as bone morphogenetic proteins to regulate the osteogenesis process on bioactive materials. However, these active factors often have the disadvantage of high cost and can not be used for a long time. In order to solve the above problems, a variety of small molecule active peptides were developed and played a good osteogenic effect. In this paper, a variety of common small molecule active peptides that induce osteogenesis were summarized and their research progress was reviewed.