Explicit analytical tuning rules for digital PID controllers via the magnitude optimum criterion.

Analytical tuning rules for digital PID type-I controllers are presented regardless of the process complexity. This explicit solution allows control engineers 1) to make an accurate examination of the effect of the controller's sampling time to the control loop's performance both in the time and frequency domain 2) to decide when the control has to be I, PI and when the derivative, D, term has to be added or omitted 3) apply this control action to a series of stable benchmark processes regardless of their complexity. The former advantages are considered critical in industry applications, since 1) most of the times the choice of the digital controller's sampling time is based on heuristics and past criteria, 2) there is little a-priori knowledge of the controlled process making the choice of the type of the controller a trial and error exercise 3) model parameters change often depending on the control loop's operating point making in this way, the problem of retuning the controller's parameter a much challenging issue.

Sealing of coronary artery aneurysm by using a new stent graft.

Coronary stenting has begun to play an increasingly important role in the management of coronary artery aneurysms. A case of successful and complete sealing of a coronary aneurysm by using a new stent graft is described. Further studies in a large patient population are required to confirm the safety and efficacy of this method.

Elective intracoronary Micro-Stent II implantation without quantitative coronary angiography or intravascular ultrasound guidance and without subsequent anticoagulation: short- and long-term results.

Intracoronary stenting has been shown to reduce acute closure and restenosis rate in patients treated with coronary angioplasty. The use of high inflation pressures and intravascular ultrasound guidance allowed the substitution of anticoagulants with antiplatelet agents but increased the cost. The aim of this study was to investigate the effectiveness, safety, and long-term outcome of the elective implantation of a relatively new type of stent (Micro-Stent II), without the use of quantitative coronary angiography or intravascular ultrasound guidance and without subsequent anticoagulation.

Intracoronary stent placement proximal to a myocardial bridge: immediate and long-term results.

The intracoronary stent placement in a lesion proximal to a myocardial bridge is of special importance and is considered to be a challenge for the interventional cardiologist. In this study 4 cases of stent implantation proximal to a coronary bridged segment are described. In all cases complications were observed after the procedure.