Effect of different structural parameters of filter rod on mechanical properties of new vena cava filter / 生物医学工程学杂志

The dynamic analysis of the implantation process of a new vena cava filter was carried out by finite element analysis method to reveal the influence of the angle, length, width and thickness of the filter rod on its mechanical properties and the inner wall of the blood vessel. The results showed that the high-stress and high-strain areas of the filter were mainly concentrated in the connection between the filter rod and the filter wire. With the increase of the angle of the filter rod, the maximum equivalent stress and the maximum elastic strain on the filter wall decreased, while the maximum equivalent stress on the vascular wall increased. With the increase of the length of the filter rod, the maximum equivalent stress and strain peak of the filter wall increased, but the maximum equivalent stress of the vessel wall decreased. With the increase of the width and thickness of the filter rod, the maximum equivalent stress of the filter wall, the maximum elastic strain and the maximum equivalent stress of the vessel wall all showed an upward trend. The static safety factor of all filter models was greater than 1, and the structure after implantation was safe and reliable. The results of this study are expected to provide a theoretical basis for the structural optimization and deformation mechanism of the new type vena cava filter.

Deformation mechanisms and compactibility of directly compressible excipients using induction tablet press / 中国药学杂志

OBJECTIVE: To study deformation behaviors of directly compressed materials using induction tableting machine. METHODS: Eighteen types of materials, which were widely used in tablet production, were selected and compressed. Their deformation behaviors and compactability were investigated by applying classic methods involving compression models, mechanical energy and elastic stretch. RESULTS: Cellulose and copovidone with lower Py and E were ranked in high TS interval; starches with lower Py, high FES and Esp, and larger E values than cellulose, were ranked in inferior TS interval; polyols and lactose materials resembling cellulose powders in appearance of Esp and Py, were of higher E values than that of the latter and mostly ranked in intermediate interval; mineral materials with highest Py and E were ranked in inferior TS interval. CONCLUSION: Copovidone and cellulose derivatives display good plastic deformation and compactability whereas Ac-Di-Sol SD711 mainly deform elastically; starch derivatives primarily undergo plastic deformation during compaction but with high FES and relatively poor compactability; polyols and lactose materials exhibit brittle characteristics during loading and the former consolidating better; mineral materials show great resistance to break and deform and have relatively high elastic recovery.