OBJECTIVE: To study the self-tapping performance test method of self-tapping bone screws based on the YY/T 1505 standard. METHODS: With reference to the method of YY/T 1505, various factors affecting the self-tapping force test was optimised, and the self-tapping force judgment method was improved. RESULTS: The experimental results showed that the self-tapping force obtained by the improved self-tapping force judgment method has good repeatability and high stability of the experimental data. At the same time, the test results of other influencing factors indicated that the manufacturer should fully consider the test material and the size of the pre-drilled hole. CONCLUSIONS An improved method for judging the self-tapping force is helpful for the repeatability and stability of the test data. This study has certain significance referring to the self-tapping performance test of self-tapping bone screws.
Biomechanical Phenomena ; Bone Screws

Left ventricular aneurysm (LVA) is a common complication of myocardial infarction. Traditional medical and surgical treatments are not effective or require high doctors' operational skills and patients' physical fitness. With the development of minimally invasive medical devices, it becomes possible for revivent TC system to treat LVA and reconstruct the left ventricle. This study introduces an existing product and its defect when used. From the perspective of clinical needs, we propose a new design of revivent TC system which realizes accurate force measurement and simplifies surgery.
Cardiac Surgical Procedures ; Heart Aneurysm ; Heart Ventricles ; Humans ; Myocardial Infarction

Biodegradable vascular stent, also known as the third generation stent, has recently been widely studied. Finite element models of three stents with the same structure and different specifications were developed. The mechanical behavior under crimping, expanding and fatigue testing were assessed by von Mises yield and Goodman convergence. The maximum stress during crimping, expanding and fatigue testing were all observed in the stent with the largest size. The results indicated that the largest stent had the highest risk of failure and also provided theoretical evidence for the worst case scenario in the fatigue testing.
Finite Element Analysis ; Polyesters ; Stents ; Stress, Mechanical

The single-use sterile vagina dilator is the common medical device mainly used for gynecological examination, and the anti-deforming capability is the key property assuring safety and efficiency. The influence factors of deformation capacity are studied and analyzed according to the testing method described in the standard YY 0336—2013.

A novel drug delivery device simulating the cardiovascular bloodfl ow pattern was introduced. The device was used to simulate the in vivo drug release in the drug-eluting stents. The results regarding the drug release rate were subject to the pattern from in vivo measurement. Therefore, the device was validated as a measurement method for in vivo drug release rate.

Two kinds of Cu-containing intrauterine contraceptive device (Cu-IUD) has been evaluated through the study on the release of copper ion and corrosion of copper surface in artificially formulated fluid. The result showed that the copper ions were released profusely from the stainless steel stents Cu-IUD in the first week of soak (25-12 microg/d), and then it became slowly and steady. The release of the copper ions from the titanium nickel shape memory alloy stents Cu-IUD were always slowly and steady in two months (0.5-5 microg/d). It obviously shows that the corrosion on copper surface of stainless steel stents Cu-IUD were more serious than titanium nickel shape memory alloy stents Cu-IUD by using 200 times microscope testing before and after soaking in formulated fluid.
Copper ; chemistry ; Corrosion ; Intrauterine Devices ; Ions ; chemistry ; Stents

OBJECTIVETo study the Cupric ion release characteristics of different copper raw materials in intrauterine device in vitro by ICP. Reveal the relationship between purity and shape of Cu-IUD copper and copper ion release.

METHODSAccording to a certain proportion, the copper raw materials were 100 times diluted into the simulated uterine solution at 37 +/- 0.5 degrees C. Replaced medium at certain time points and collected soaking liquid. Using ICP analyzed the concentration of copper ion released.

RESULTSThe largest daily release of copper ions was in the first 7 days. There was no statistically significant difference between the copper ion release amount of 99.99% and 99.95% purity copper wire (P > 0.05). The release of copper ion of the copper wire was far greater than that of the copper pipe in early stage (P < 0.01). The release amount decreased and stabilized at 56 day.

CONCLUSIONRelease characteristics of copper ion could effectively analysis by ICP. And in the same area, the release amount of copper ions of copper wire was greater than that of copper pipe.

The finite element method was used for simulating the mechanical performance and fatigue safety of three different structures of Nitinol stent. According to the actual situation, after proposing reasonable assumptions and simplification, the geometry model and finite element model establishment, material mode selection and boundary condition setting are completed. The strain and fatigue life of different stent edges wide (omega) or strut angle (theta) are computed. The result can provide a valuable reference for the optimal design of stent.
Alloys ; Finite Element Analysis ; Prosthesis Design ; Stents

The finite element method was used for simulating the mechanical performance and fatigue safety of three different structures of Nitinol stent. According to the actual situation, after proposing reasonable assumptions and simplification, the geometry model and finite element model establishment, material mode selection and boundary condition setting are completed. The strain and fatigue life of different stent edges wide (ω) or strut angle (q) are computed. The result can provide a valuable reference for the optimal design of stent.

Objective To study the Cupric ion release characteristics of dif erent copper raw materials in intrauterine device in vitro by ICP. Reveal the relationship between purity and shape of Cu-IUD copper and copper ion release. Methods According to a certain proportion, the copper raw materials were 100 times diluted into the simulated uterine solution at 37± 0.5 oC. Replaced medium at certain time points and col ected soaking liquid. Using ICP analyzed the concentration of copper ion released. Results The largest daily release of copper ions was in the first 7 days. There was no statistical y significant difference between the copper ion release amount of 99.99%and 99.95%purity copper wire ( P>0.05). The release of copper ion of the copper wire was far greater than that of the copper pipe in early stage (P<0.01).The release amount decreased and stabilized at 56 day. Conclusion Release characteristics of copper ion could effectively analysis by ICP. And in the same area, the release amount of copper ions of copper wire was greater than that of copper pipe.