Advances in Science and Technology Vol. 57

Abstract: Superelastic 0.1mm diameter Ti-Ni filaments are used to manufacture braided orthopedic cable for bone fixation. Biomechanical conditions for this application generally have a cyclic nature, and therefore it becomes important to evaluate the influence of the installation (mean) strain on the fatigue life of these filaments. Uniaxial tension cyclic testing of Ti-Ni filaments is performed in a water bath at 37°C with a 2Hz frequency of to 100 000 cycles. Strain-controlled testing conditions are as follows: alternating strain magnitude varies between 0.64 and 3.64% with mean strain range between 1.32 and 7.1%. Based on the premises that the minimum strain should be high enough to prevent any loss of tension in the tested specimen and that the maximum strain should not bring the specimen to failure during the first loading cycle, the total strain magnitude is encompassed between 0.68 and 8.94%. The results obtained provide a better understanding of the impact mean strain has on the fatigue life of superelastic Ti-Ni alloys.

Abstract: Currently, a minimally invasive surgery called stenting is extensively used to increase the lumen of partially obstructed arteries. Unfortunately, restenosis, a postoperative phenomenon in which the lumen of the artery is reduced due to a traumatism of the artery, is still a concern. The most popular solution that has been adopted by stent manufacturers comprises drug-eluting stents. This paper presents a new stent concept in which the treatment of restenosis is carried out from a completely different angle. Indeed, instead of traumatizing the artery, and then trying to control restenosis with drugs, the new stent minimizes the traumatism of the artery by expanding itself, not instantaneously, but progressively, and in a controlled manner. To achieve this, a nitinol stent over which a series of polymer rings are installed tries to reach a fully deployed configuration, but the polymer rings, which act as a retainer, become soft over time due to creeping. Thus, after the initial deployment in the artery, the stent continues its expansion autonomously over an extended period of time (a few weeks). It is believed that the artery has enough time to adapt to the expansion, leading to minimum traumatism. This paper presents the stent design.

Abstract: This paper describes the early conception and latest developments of electroactive polymer (EAP)- based sensors, actuators and power sources, implemented as wearable devices for smart electronic textiles (e-textiles). Such textiles, functioning as multifunctional wearable human interfaces, are today considered relevant promoters of progress and useful tools in several biomedical field, such as biomonitoring, rehabilitation and telemedicine. This paper presents the more performing EAPbased devices developed by our lab and other research groups for sensing, actuating and energy harvesting, with reference to their already demonstrated or potential applicability to electronic textiles.

Abstract: The commercial systems using intelligent textiles that start to appear on the market perform physiological measurements such as body temperature, electrocardiogram, respiration rate, etc. and target sport and healthcare applications. Biochemical measurements of body fluids combined with available health monitoring technology will extend these systems by addressing important health and safety issues. BIOTEX, standing for Bio-sensing Textile for Health Management, is a European project, which aims at developing dedicated biochemical sensing techniques that can be integrated into textiles. Such a system would be a major breakthrough for personalized healthcare and would allow for the first time the monitoring of body fluids with sensors distributed in a textile substrate. The potential applications include isolated people, convalescents and patients with chronic diseases, sports performance assessment and training. The project is addressing several challenges, among which: sweat collection and delivery to the sensors, high sensitivity with a wearable system, wearability issues, sensor calibration and lack of research in sweat analysis.