Objective This study aimed to explore the effect of peripheral blood mesenchymal stem cells combined with porous absorbable gelatin sponge/self assembling peptide composite scaffolds on SD rat femoral con-dyle bone defect reconstruction and provide a new strategy for the repair of bone defects. Methods 30 female SD rats,8W age,were randomly divided into 3 groups,10 every group.The group A was blank control group,group B was porous absorbable gelatin sponge/self assembling peptide composite scaffold group,and group C was periph-eral blood mesenchymal stem cells combined with porous absorbable gelatin sponge/self assembling peptide compos-ite scaffold group. The effect of osteogenesis was observed by paraffin section,hematoxylin eosin staining,X-ray examination,and Micro-CT scanning in 3 dimensional reconstruction of femoral condyle defect. Results Imaging examination showed that the experimental group had better osteogenesis effect. Histological examination showed that a lot of new bone tissue was found in group C,while only a small amount of new bone was found in the group of A and B. Conclusions The experiment shows that peripheral blood mesenchymal stem cells as the seed cells for tissue engineering,combined with porous absorbable gelatin sponge-self assembling peptide has better ability to repair bone defects,and has good application prospect,which is worthy of further research.

Microplastics refer to plastic fibers, particles, or films with a particle size less than 5 mm, and microplastics pollution has become one of the major global environmental problems. Microplastics can be exposed to the human body through ingestion, inhalation and skin contact, affecting maternal and fetal health through mechanisms such as cytotoxicity and signal transduction, energy homeostasis and metabolic disorders, immune dysfunction, and as carriers of microorganisms or toxic chemicals. The purpose of this paper is to review the physical and chemical properties of microplastics, human exposure pathways, maternal-fetal effects, and its mechanisms.

Objective To investigates the applicability of cutting balloon in the pretreatment of superficial coronary artery calcified lesions, so as to decrease the occurrence of serious consequences in the treatment of calcified lesions. Methods The effect of cutting balloon on calcified plaques with different curvatures, thickness, and length was analyzed using the finite element method, with normal balloon as a control. The thickness of calcified plaque was set to 0.3 mm and 0.4 mm, and the length was set to 2 mm and 4 mm. The calcification degree was set to 120°, 180°, 270°and 360° according to the intravenous ultrasound (IVUS) calcification severity grading, with a total of 16 types of calcified plaques. The brittle fracture module was used to simulate calcification fracture of calcified plaques, and virtual stent implantation was carried out based on pretreatment simulation. The effect of pretreatment was evaluated by calcification fracture condition and stent roundness. Results For superficial calcification lesions, in lesions less than 120°, the balloon could not remove the calcification plaque obstruction, and the stent roundness rate was 82.75%. In 180° calcified lesions with thickness of less than 0.3 mm, the calcification was broken by cutting balloon under 1 215.9 kPa expansion pressure, and the post-stent roundness rate was 74.42%; normal balloon could not cause calcification fracture under safe expansion pressure (1 418.55 kPa). In 270°calcified lesions with thickness less than 0.3 mm, the normal balloon produced 3 fractures under 1 013.25 kPa expansion pressure. The cutting balloon produced 2 fractures under 1 013.25 kPa expansion pressure, and the balloon could not fracture the circular calcified lesions with thickness of 0.3 mm. Conclusions Cutting balloon is recommended for 180°calcified lesions with thickness less than 0.3 mm, the normal balloon is recommended for 270°calcified lesions, and balloon pretreatment is not recommended for annular lesions with thickness greater than 0.3 mm.