ABSTRACT
A kind of active catheter used for minimally invasive surgery and actuated by shape memory alloy (SMA) was developed in this paper. The outer diameter of the catheter is 1.25 mm. The catheter was designed to consist of several bending units for achieving a large bending angle, but at the same time not increasing the outer diameter too much. It was considered that the deflection curve of axis of the catheter is determined by the output force of the SMA actuators. Based on large deflection theory, the deflection curve equation of the axis of the catheter was set up using precise form of the curvature. Through integral transform, the length and output force of each SMA actuator under the anticipative attitude of the tip of the active catheter were obtained, and the accurate coordinate of the center of the joint was givein. This study has provided great convenience to get control of the catheter, and has improved, to a certain extent, the design philosophy of problems such as active catheter.
Subject(s)
Humans , Alloys , Blood Vessels , Catheterization , Computer-Aided Design , Elasticity , Equipment Design , Minimally Invasive Surgical Procedures , Models, TheoreticalABSTRACT
Objective: To explore the effects of puerarin on insulin resistance (IR) and abormal lipid and fibrinolytic activity in patients with type 2 diabetes mellitus (DM). Methods: Eighty patients with type 2 DM were divided randomly into two groups: 40 cases in the puerarin group and 40 cases in the routine treatment group. The conventional treatment of the two groups were the same. Additionally, patients in the puerarin group were given puerarin 500 mg in 250 ml of normal saline for intravenous dripping, once a day with a therapeutic course of 3 weeks. The changes of fast blood glucose (FBG), lipid, insulin and plasminogen activator inhibitorCD*21 (PAICD*21) activity were measured before and after treatment,and the insulin sensitivity index (ISI) was calculated. Forty healthy subjects were taken as controls. Results: ①After 3 weeks of treatment , compared with the control group, in type 2 DM patients, FBG, fast insulin (FINS), total cholesterol (TC), triglyerides (TG), low-density lipoprotein cholesterol (LDLCD*2C) levels and PAICD*21 activity were higher, ISI and HDLCD*2C were lower than those of the healthy controls. FINS and ISI were well correlated with lipid and fibrinolytic abnormality. ②After puerarin treatment, FINS, TC, TG, LDLCD*2C level , and PAICD*21 activity decreased and ISI, HDLCD*2C increased significantly (all P