Virtual-Reality Simulator System for Double Interventional Cardiac Catheterization Using Fractional-Order Vascular Access Tracker and Haptic Force Producer.

This study proposes virtual-reality (VR) simulator system for double interventional cardiac catheterization (ICC) using fractional-order vascular access tracker and haptic force producer. An endoscope or a catheter for diagnosis and surgery of cardiovascular disease has been commonly used in minimally invasive surgery. It needs specific skills and experiences for young surgeons or postgraduate year (PGY) students to operate a Berman catheter and a pigtail catheter in the inside of the human body and requires avoiding damaging vessels. To improve the training in inserting catheters, a double-catheter mechanism is designed for the ICC procedures. A fractional-order vascular access tracker is used to trace the senior surgeons' consoled trajectories and transmit the frictional feedback and visual feedback during the insertion of catheters. Based on the clinical feeling through the aortic arch, vein into the ventricle, or tortuous blood vessels, haptic force producer is used to mock the elasticity of the vessel wall using voice coil motors (VCMs). The VR establishment with surgeons' consoled vessel trajectories and hand feeling is achieved, and the experimental results show the effectiveness for the double ICC procedures.

[Left ventricular function in newborn infants of mothers with gestational diabetes mellitus].

OBJECTIVE: To evaluate left ventricular function in newborn infants of mothers with gestational diabetes mellitus (GDM). METHODS: Forty newborn infants of mother with GDM (GDM group) and forty normal newborn infants (control group) were enrolled in this study. Two-dimensional speckle tracking imaging was used to measure interventricular septal thickness, posterior left ventricular wall thickness and left ventricular ejection fraction in both groups. Left ventricular rotation and torsion were evaluated for all participants. RESULTS: Interventricular septal thickness in the GDM group was much higher than in the control group (0.45±0.06 mm vs 0.34±0.05 mm; P<0.05). Posterior left ventricular wall thickness in the GDM group was also higher than in the control group (0.45±0.17 mm vs 0.31±0.02 mm; P<0.05). There was no difference in the left ventricular ejection fraction between the two groups (P>0.05). Peak subendocardial rotation, peak subepicardial rotation, peak bulk rotation and peak mural torsion were higher in the GDM group than in the control group (P<0.05). CONCLUSIONS: Cardiac function may be impaired in newborn infants of mothers with GDM, with changes in left ventricular shape and abnormalities of left ventricular rotation and torsion. However, infants have a normal ventricular blood ejection under the cardiac compensation. Two-dimensional speckle tracking imaging technique can be used for early detection of left ventricular function.

Activity enhancement and stabilization of lipase from Pseudomonas cepacia in polyallylamine-mediated biomimetic silica.

Triacylglycerol lipase from Pseudomonas cepacia and Fe(3)O(4) magnetic nanoparticles were encapsulated simultaneously within biomimetic silica through the catalysis of polyallylamine. The encapsulation efficiency reached 96% with an activity recovery of 51%. After 5 h at 37°C, the activities of the free and encapsulated lipases decreased by 77 and 16%, respectively. Addition of 10 and 15 mol% trimethylmethoxysilane to tetramethoxysilane during encapsulation doubled the lipase activity while inclusion of 50 and 60 mol% γ-(methacryloxypropyl)-trimethoxysilane tripled the activity. Thus, such encapsulation not only stabilized P. cepacia lipase but also could enhance the activity by varying silane additives.

Peripheral arterial disease screening for hemodialysis patients using a fractional-order integrator and transition probability decision-making model.

Atherosclerosis and resultant peripheral arterial disease (PAD) are common complications in patients with type 2 diabetes mellitus or end-stage renal disease and in elderly patients. The prevalence of PAD is higher in patients receiving haemodialysis therapy. For early assessment of arterial occlusion using bilateral photoplethysmography (PPG), such as changes in pulse transit time and pulse shape, bilateral timing differences could be used to identify the risk level of PAD. Hence, the authors propose a discrete fractional-order integrator to calculate the bilateral area under the systolic peak (AUSP). These indices indicated the differences in both rise-timing and amplitudes of PPG signals. The dexter and sinister AUSP ratios were preliminarily used to separate the normal condition from low/high risk of PAD. Then, transition probability-based decision-making model was employed to evaluate the risk levels. The joint probability could be specified as a critical threshold, < 0.81, to identify the true positive for screening low or high risk level of PAD, referring to the patients' health records. In contrast to the bilateral timing differences and traditional methods, the proposed model showed better efficiency in PAD assessments and provided a promising strategy to be implemented in an embedded system.

Bilateral photoplethysmography for arterial steal detection in arteriovenous fistula using a fractional-order decision-making quantizer.

As inflow and outflow stenoses worsen, both flow resistance and pressure increase in the stenotic vascular access. During dialysis, when blood flow decreases, it may retrograde from the peripheral artery through the palmar arch to the arterial anastomosis site. Arterial steal syndrome (ASS) causes distal hypoperfusion, resulting in hand ischemia or extremity pain and edema. Hence, this study proposes the bilateral photoplethysmography (PPG) for ASS detection in arteriovenous fistulas. The decision-making quantizer utilizes the fractional-order feature extraction method and a non-cooperative game (NCG) framework to evaluate the ASS risk level. Bilateral asynchronous PPG signals have significant differences in the rise time and amplitude in relation to the degree of stenosis. The fractional-order self-synchronization error formulation is a feature extraction method used to quantify bilateral differences in blood flow changes between the dexter and sinister PPG signals. The NCG model as a method of decision-making is then employed to evaluate the ASS risk level. Using an acoustic Doppler measurement, the resistive (Res) index is also used to evaluate the vascular access stenosis at the arterial anastomosis site. In contrast with alternative methods including the high-sensitivity C-reactive protein level or Res index, our experimental results indicate that the proposed decision-making quantizer is more efficient in preventing ASS during hemodialysis treatment.

[Left versus right ventricular Tei index for evaluating third-trimester fetal cardiac function in pregnancy-induced hypertension syndrome].

OBJECTIVE: To investigate the value of Tei index and the sensitivity of left versus right ventricular Tei index in evaluating the fetal cardiac function in pregnancy-induced hypertension syndrome in the third trimester. METHODS: Fetal echocardiograms were performed in 30 women with pregnancy-induced hypertension (PIH) syndrome and 55 with normal pregnancy of the third trimester. Tei index was obtained by calculating the ratio of the isovolumic time (isovolumic contraction and relaxation time) to the ejection time of the left and right ventricle. Comparisons of the Tei index were made between the PIH group and control group, and also between the left and right ventricles in each group. RESULTS: Significant difference was found in the left and right ventricular Tei index between PIH group and control group. No difference was noted between the left and right ventricular Tei index in the PIH group. CONCLUSIONS: Tei index is a useful indicator in evaluating fetal global cardiac function, for which purpose the left ventricular Tei index can be as sensitive as the right ventricular Tei index.