Novel Floating General Element Simulators Using CBTA

In this study, a novel floating frequency dependent negative resistor (FDNR), floating inductor, floating capacitor and floating resistor simulator circuit employing two CBTAs and three passive components is proposed. The presented circuit can realize floating FDNR, inductor, capacitor or resistor depending on the passive component selection. Since the passive elements are all grounded, this circuit is suitable for fully integrated circuit design. The circuit does not require any component matching conditions, and it has a good sensitivity performance with respect to tracking errors. Moreover, the proposed FDNR, inductance, capacitor and resistor simulator can be tuned electronically by changing the biasing current of the CBTA or can be controlled through the grounded resistor or capacitor. The high-order frequency dependent element simulator circuit is also presented. Depending on the passive component selection, it realizes high-order floating circuit defining as V(s) = snAI(s) or V(s) = s-nBI(s). The proposed floating FDNR simulator circuit and floating high-order frequency dependent element simulator circuit are demonstrated by using PSPICE simulation for 0.25 μm, level 7, TSMC CMOS technology parameters

Synthetic Transformer Design Using Commercially Available Active Components

In this study, a novel synthetic transformer (ST), namely mutually coupled circuit, using commercially available active components such as current feedback operational amplifiers (CFOAs) is proposed. The proposed ST uses four CFOAs, two grounded capacitors and five resistors. It possesses only resistors but no capacitors attached in series to W/X terminals of the CFOAs; consequently, its high-frequency performance is well. Nevertheless, it needs a single matching condition for symmetrical coupling. As an application example, a double-tuned band-pass filter is given. The validity of the proposed circuit is demonstrated through several SPICE simulations and experiments

Surgical placement of left ventricular lead for cardiac resynchronisation therapy after failure of percutaneous attempt

WOS: 000397242600006PubMed ID: 28262910Objective: Cardiac resynchronisation therapy has been shown to be an effective treatment to improve functional status and prolong survival of patients in advanced chronic heart failure. This study assessed the surgical outcomes of left anterior mini-thoracotomy for the implantation of left ventricular epicardial pacing leads in cardiac resynchronisation therapy. Methods: Our study consisted of 30 consecutive patients who underwent cardiac resynchronisation therapy with a left thoracotomy between November 2010 and April 2012 in our clinic. Postoperative follow up included the assessment of New York Heart Association (NYHA) functional class, electrocardiography and echocardiography. Results: There were 22 male and eight female patients with a mean age of 68 +/- 5.04 years. All patients were in NYHA class III or IV. Pre-procedure mean left ventricular ejection fraction was 28.1 +/- 4.5% and post-procedural ejection fraction improved to 31.7 +/- 5.1%. The pre-operative QRS duration changed from 171.7 +/- 10.8 to 156.2 +/- 4.4 ms after the operation. Also there was a significant reduction in left ventricular end-diastolic dimension from 6.98 +/- 0.8 to 6.72 +/- 0.8 mm (p < 0.05), but no change in left ventricular end-systolic dimension and severity of mitral regurgitation. All patients had successful surgical left ventricular lead placement. There was no procedure-related mortality. The mean follow-up time was 40.4 months. Conclusion: Surgical epicardial left ventricular lead placement procedure is a safe and effective technique in patients with a failed percutaneous attempt

Comparison of Renoprotective Effect of Dabigatran With Low-Molecular-Weight Heparin

WOS: 000373916700008PubMed ID: 25681331Objective: The susceptibility of tissue to ischemia-reperfusion (I/R) injury is a major obstacle to tissue regeneration and cellular survival. In this study, we investigated the possible renoprotective effect of dabigatran in an experimental renal I/R model. Method: A total of 25 rats were randomly divided into 5 equal groups. The control group was used to obtain basal values of oxidant and antioxidant biomarkers. The sham group was used to obtain renal prolidase and malondialdehyde (MDA) levels after renal ischemia (for 45 minutes) and reperfusion (for 1 hour). A standard diet was followed. Oral 15 mg/kg dabigatran etexilate was administrated to group I, intraperitoneal 250 U/kg enoxaparin sodium was administrated to group II, and intraperitoneal 250 U/kg bemiparin sodium was administrated to group III for 1 week before the renal I/R was performed. Renal tissue samples were obtained during the first hour of reperfusion to detect renal prolidase and MDA levels in these groups, after which the rats were euthanized. Results: Renal prolidase levels were significantly higher in the sham group compared with the control group (1834.2 982.3 U/g protein vs 238.8 +/- 43.6U/g protein; P = .001). Lower prolidase levels were observed in groups II (838.7 +/- 123.8 U/g protein) and III (1012.9 +/- 302.3 U/g protein), and the lowest prolidase levels occurred in group I (533.8 +/- 96.2 U/g protein; P < .05) when compared with the sham group. The MDA levels were significantly lower (P < .05) in groups I, II, and III (163.9 +/- 41.5, 185.4 +/- 51.0, and 138.2 +/- 22.6 mol/g protein, respectively) compared with the sham group. Conclusion: Dabigatran etexilate, a univalent direct thrombin inhibitor, may protect the renal tissue more effectively when compared to low-molecular-weight heparins

Angiographic evaluation of graft patency in robotic-assisted coronary artery bypass surgery: 8 year follow-up

WOS: 000333298800015PubMed ID: 24293289BackgroundRobotic telemanipulation systems have emerged as facilitating tools that enhance minimally invasive cardiac surgery.The purpose of this study was to evaluate graft patency by a combination of invasive and non-invasive coronary angiography methods in robotic-assisted coronary artery surgery(CABG) for optimal quality control. MethodsBetween April 2004 and February 2012, patients who had robotic-assisted CABG were called to have cardiac catheterization or multislice computed tomographic angiography to evaluate graft patency. ResultsOne hundred patients out of a total 250 cases were followed for graft patency for a mean period of 60.3 23.8 (range 12-94) months. Mean operative time and left internal mammary artery harvest time was 165.96 +/- 19.5 and 41.74 +/- 5.9 (range 30-55) min. Postoperative graft patency rate was 94% and freedom from target vessel re-interventions was 98%. ConclusionRobotic-assisted CABG can be accomplished with low morbidity, mortality and re-intervention rates. It is a safe procedure in selected patients and produces excellent mid-term graft patency. Copyright (c) 2013 John Wiley & Sons, Ltd