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

Surgical suture is a common medical device made extensive use of hold body tissues together after an injury or surgery. Suture sizes are associated with the requirement of diameter and tensile strength in standard. They correspond with one by one. Suture sizes should be unified, standardized and correctly marked for correct and convenient selection in surgery. Using the average diameter of single suture is more scientific and reasonable than that of multiple sutures in marking.
Suture Techniques ; Sutures ; Tensile Strength

Vickers hardness is widely used in the performance testing of the metallic medical devices. It discusses the relationship between different test force and the uncertainty by mathematical simulation and experiment. With the increase of test force its uncertainty becomes smaller at 400 times magnification. If you can, you should try to choose a large test force, in order to improve the accuracy and repeatability. In the actual testing process, it is best not to use the micro vickers hardness test.
Equipment and Supplies ; Hardness Tests ; Materials Testing