Virtual Ring Research Articles

Sensing local field potentials with a directional and scalable depth electrode array

Objective. A variety of electrophysiology tools are available to the neurosurgeon for diagnosis, functional therapy, and neural prosthetics. However, no tool can currently address these three critical needs: (a) access to all cortical regions in a minimally invasive manner; (b) recordings with microscale, mesoscale, and macroscale resolutions simultaneously; and (c) access to spatially distant multiple brain regions that constitute distributed cognitive networks. Approach. We modeled, designed, and demonstrated a novel device for recording local field potentials (LFPs) with the form factor of a stereo-electroencephalographic electrode and combined with radially distributed microelectrodes. Main results. Electro-quasistatic models demonstrate that the lead body amplifies and shields LFP sources based on direction, enabling di rectional sensitivity and sc alability, referred to as the directional and scalable (DISC) array. In vivo, DISC demonstrated significantly improved signal-to-noise ratio, directional sensitivity, and decoding accuracy from rat barrel cortex recordings during whisker stimulation. Critical for future translation, DISC demonstrated a higher signal to noise ratio (SNR) than virtual ring electrodes and a noise floor approaching that of large ring electrodes in an unshielded environment after common average referencing. DISC also revealed independent, stereoscopic current source density measures whose direction was verified after histology. Significance. Directional sensitivity of LFPs may significantly improve brain–computer interfaces and many diagnostic procedures, including epilepsy foci detection and deep brain targeting.

Effectiveness of high implantation of SAPIEN 3 in preventing pacemaker implantation: A propensity score analysis

BackgroundIn transcatheter aortic valve implantation, high implantation on the aortic annulus may prevent conduction pathway injury, leading to a decrease in the rate of permanent pacemaker implantation. AimTo assess the impact of high implantation of SAPIEN 3 on the prevention of permanent pacemaker implantation. MethodsSince August 2020, we have performed high implantation by fluoroscopically positioning the lower part of the lucent line at the virtual basal ring line on a coplanar view before valve implantation. Patients treated before the adoption of this method were defined as the conventional group. We compared the high implantation group with the conventional group using propensity score analysis. ResultsOverall, the high implantation group (n=95) showed a significantly shorter ventricular strut length than the conventional group (n=85): median 1.3 (interquartile range 0.2–2.4) mm vs 2.8 (1.8–4.1) mm (P<0.001). The permanent pacemaker implantation rate was significantly lower in the high implantation group than in the conventional group (2.1% vs 11.8%; P=0.009). According to 100 propensity score analyses based on multiple imputation and the selection of appropriate covariates, the median P value for the comparison of permanent pacemaker implantation rates after transcatheter aortic valve implantation between the high implantation group and the conventional group ranged between 0.001 and 0.017, indicating a more significant reduction in the permanent pacemaker implantation rate in the high implantation group than in the conventional group. Neither valve dislodgement nor the need for a second valve was observed in either group. ConclusionsThe high implantation of SAPIEN 3 successfully decreases ventricular strut length, reducing the permanent pacemaker implantation rate after transcatheter aortic valve implantation.

Ultraviolet Response in Coplanar Silicon Avalanche Photodiodes with CMOS Compatibility.

Highly sensitive ultraviolet (UV) photodetectors are highly desired for industrial and scientific applications. However, the responsivity of silicon photodiodes in the UV wavelength band is relatively low due to high-density Si/SiO2 interface states. In this paper, a coplanar avalanche photodiode (APD) was developed with a virtual guard ring design. When working in Geiger mode, it exhibited a strong UV response. The responsivity of 4 × 103 A/W (corresponding to a gain of 8 × 106) at 261 nm is measured under the incident power of 0.6 μW with an excess bias of 1.5 V. To the best of our knowledge, the maximum 3-dB bandwidth of 1.4 GHz is the first report ever for a Si APD when working in the Geiger mode in spite of the absence of an integrated CMOS read-out circuit.

Update on supra-annular sizing of transcatheter aortic valve prostheses in raphe-type bicuspid aortic valve disease according to the LIRA method.

Recent evidence has shown that transcatheter heart valve (THV) anchoring in bicuspid aortic valve (BAV) patients occurs at the level of the raphe, known as the LIRA (Level of Implantation at the RAphe) plane. Our previous work in a cohort of 20 patients has shown that the delineation of the perimeter and device sizing at this level is associated with optimal procedural outcome. The goals of this study were to confirm the feasibility of this method, evaluate 30-day outcomes of LIRA sizing in a larger cohort of patients, assess interobserver variation and reproducibility of this sizing methodology, and analyse the interaction of LIRA-sized prostheses with the surrounding anatomy. The LIRA sizing method was applied to consecutive patients presenting to our centre with raphe-type BAV disease between November 2018 and October 2021. Supra-annular self-expanding THVs were sized based on baseline CT scan perimeters at the LIRA plane and the virtual basal ring. In cases where there was discrepancy between the two measurements, the plane with the smallest perimeter was considered the reference for prosthesis sizing. Post-procedural device success, defined according to Valve Academic Research Consortium-2 (VARC-2) criteria, was evaluated in the overall cohort. A total of 50 patients (mean age 80 ± 6 years, 70% male) with raphe-type BAV disease underwent transcatheter aortic valve replacement (TAVR) using different THV prostheses. The LIRA plane method appeared to be highly successful (100% VARC-2 device success) with no procedural mortality, no valve migration, no moderate-severe paravalvular leak, and low transprosthetic gradients (residual mean gradient 8.2 ± 3.4 mmHg). There were no strokes, no in-hospital or 30-day mortality, and an incidence of in-hospital pacemaker implantation of 10%. Furthermore, measurement of the LIRA plane perimeter was highly reproducible between observers (r = 0.980; P < 0.001) and predictive of the post-procedural prosthetic valve perimeter on CT scanning (r = 0.981; P < 0.001). We confirm the feasibility of supra-annular sizing using the LIRA method in a large cohort of patients with high procedural success and good clinical outcomes at 30 days. Application of the LIRA method optimizes THV prosthesis sizing in patients with raphe-type BAV disease.

C31 UPDATE ON SUPRA–ANNULAR SIZING OF TRANSCATHETER AORTIC VALVE PROSTHESES IN RAPHE–TYPE BICUSPID AORTIC VALVE DISEASE ACCORDING TO THE LIRA METHOD

Abstract Aims Recent evidences have shown that transcatheter heart valve (THV) anchoring in BAV patients might occur at the raphe–level, known as the LIRA (Level of Implantation at the RAphe) plane. A novel supra–annular sizing method based on the measurement of the perimeter at the raphe–level (LIRA–method) was shown to be safe and effective in 20 consecutive BAV patients with severe aortic stenosis. The purpose of this study was to confirm the safety and the efficacy of the LIRA method in a larger study population. Methods the LIRA plane method was applied to all consecutive patients with raphe–type BAV disease between November 2018 to October 2021 in our centre. We prospectively sized TAVI prosthesis according to the manufacture recommendations on the basis of baseline CT scan perimeters at the LIRA plane. Post–procedural device success, defined according to Valve Academic Research Consortium–2 (VARC–2) criteria, was evaluated in the overall cohort. Results 50 patients were identified as having a raphe–type BAV disease at pre–TAVI CT scans. Mean patient age was 80 ± 6.2 years. Three different BAV anatomies (47 patients with BAV type 1 and 3 patients with BAV type 2) were implanted with different types of TAVI prostheses (28 Acurate Neo/Neo 2, 21 Core Valve Evolut R/Pro,1 Lotus) sized prospectively according to the LIRA plane method. In all patients, there was a significant discrepancy between LIRA and virtual basal ring (VBR) (mean perimeter LIRA 73.1 ± 8.3 mm vs mean perimeter VBR 81.5 ± 6.6 mm; p &amp;lt; 0.001). The median prosthesis size was 26 mm (23–27). Pre–dilatation was frequently performed (88%) with a median balloon size of 20 mm (20–23), whereas post–dilatation was applied in 26% of the cases with a median balloon size of 23 mm (22–24). The LIRA plane method appeared to be highly successful (100% VARC–2 device success) with no procedural mortality, no valve migration, residual trivial/mild paravalvular leak with no cases of moderate–severe regurgitation and no cases of mean gradient &amp;gt;20 mmHg pre–discharge. The rate of new pacemaker implantation was 10%. Conclusions Supra–annular sizing according to the LIRA plane method confirmed to be safe with a high device success in a larger study population. The application of the LIRA plane method might optimize TAVI prosthesis sizing in patients with raphe–type BAV disease.

Surgical implications of variations in the anatomy of the aortic root.

Introducing their recent experience with the technically demanding valvar-sparing surgery on the aortic root, Oishi et al. [1] emphasize that ‘the surgeon must have sound knowledge of the anatomy and function of the aortic valve’. Better had they stated that knowledge was required regarding the features of the aortic root, which extends from the virtual basal ring to the sinutubular junction [2], since the valve is but 1 component of this complex structure. Discussion of its components has been hampered over recent decades by virtue of the numerous terms used for description. As was shown by the questionnaire conducted a decade ago by the German surgeons [3], it still remains problematic to reach a consensus on these issues. The surgeons from Tokyo have focussed on the complications of inadvertent perforation of the right atrium, and damage to the tricuspid valve. They have shown that, in their hands, variations in the rotation of the root relative to the base of the left ventricle influenced these complications. Such variation has been highlighted as an important feature for those undertaking transcatheter replacement of the aortic valve [4], but thus far has received little attention amongst the surgical community. From their stance, they classified the observed rotation as seen by the imager from the apex of the ventricle and clarified how this is mirror-imaged when viewed by the surgeon. As is now increasingly the case, their findings in the operating room supplemented the changes previously diagnosed using computed tomographic interrogation. This technique is rapidly establishing itself as the new ‘gold standard’ for the visualization of cardiac anatomy. It has the inestimable advantage of showing the anatomy in the setting of the heart within the chest and revealing the subtleties without the need to distort the relationships relative to neighbouring structures. As the Tokyo surgeons emphasize, however, those using computed tomography show their images as seen from the ventricular apex, whereas the cardiac surgeon views the aortic root from the atrial aspect. As long as this difference is kept in mind, there will be no problem, but it is capable of creating confusion. Rotation of the root from its normal position was observed in around one-sixth of their patients, with most having counter-clockwise rotation as defined from the perspective of the imager. Counter-clockwise rotation meant that a greater proportion of the right coronary sinus was related to the wall of the right atrium. This resulted in increased difficulty in dissecting the sinus, with an increased incidence of right atrial perforation and damage to the tricuspid valve.

Energy-Aware Routing Protocol with Fuzzy Logic in Industrial Internet of Things with Blockchain Technology

It is the expansion and use of the Industrial Internet of Things (IIoT) in various industrial sectors and applications that are referred to as the Industrial Internet of Things (IIoT). The Industrial Internet of Things includes industrial applications such as robots, medical devices, and software-defined manufacturing processes. In terms of energy conservation, routing is extremely essential. The creation of an energy effectual steering procedure leads to a substantial rise in energy consumption. To minimize network traffic and increase network life, the article presented an Industrial IoT Fuzzy Logic Energy-Aware Routing Protocol (FLEA-RPL), which decreases network traffic as well as improves network life. The most suitable parent for data transfer is selected based on, among other things, the routing parameters charge, residual energy, and expected transmission count. Since the load routing metric is taken into consideration during the construction of the route, the data traffic is spread across the network. This increases network’s lifetime while maintaining a high packet delivery ratio. The proposed work proposes a Multilayer Energy-Aware Aware RPL (MCEA-RPL) cluster for the Internet of Things to decrease network data traffic while increasing the lifetime of the network. It is split into three phases, each including the creation of network rings, intraring divisions, and intercluster routing. First and foremost, the virtual ring is created in the network. Secondly, each ring forms an identical cluster and chooses the CH node. Finally, it is responsible for the maintenance and performance of the DODAG. Data transfer from the lesser sheet to the DODAG root is known as data transfer. By using Blockchain technology, the lifetime of a network may be extended by reducing the number of identical data package transfers. This article offers Enhanced Mobility Support RPL (EM-RPL) in Industrial IoT which enhances mobility support with blockchain and spreads system generation. It comprises two processes: a collection of the parental static node and selection of the parent moving node. The static parent selection method uses routing metrics load and residual energy to identify the parent that is most suited for data transfer. Two phases of mobile parent selection must be distinguished: data transmission and route rediscovery. The mobile node utilizes furious logic to compute the hand-off value of the metric packet errors ratio and the signal strength indication received from the base station. If the hand-off value exceeds the threshold limit, the DODAG route has to be changed to work correctly. The EM-RPL thus increases the package delivery rate by reducing the amount of route interruption caused by mobility, while offering an efficient handling mechanism.

Diversity and determinants of the sigmoid septum and its impact on morphology of the outflow tract as revealed using cardiac computed tomography.

The sigmoid septum has been generally evaluated subjectively and qualitatively, without detailed examination of its diversity, impact on the morphology of the left ventricular outflow tract (LVOT), and anatomical background. We enrolled 100 patients without any background cardiac diseases (67.5 ± 12.8 years old; 43% women) who underwent cardiac computed tomography. Basal septal morphology was evaluated using antero-superior and medial bulging angles (bidirectional angulation of the basal septum relative to the LVOT). The eccentricity index of the LVOT, area narrowing ratio (LVOT/virtual basal ring area), aortic-to-left ventricular axial angle (angulation of the aortic root relative to the left ventricle), and wedged height (non-coronary aortic sinus to inferior epicardium distance) were also quantified. The antero-superior bulging, medial bulging, aortic-to-left ventricular axial angles, LVOT eccentricity index, area narrowing ratio, and wedged height were 76° ± 17°, 166° ± 27°, 127° ± 9°, 1.8 ± 0.5, 1.0 ± 0.2, and 41.2 ± 9.1mm, respectively. Both bulging angles were correlated with each other and contributed to the narrowing and deformation of the LVOT. Angulated aortic root was not correlated with either bidirectional septal bulge or LVOT narrowing. Clockwise rotation of the aortic root rotation was an independent predictor of prominent antero-superior septal bulge. Deeper aortic wedging was a common independent predictor of bidirectional septal bulge. The extent of septal bulge varies in normal hearts. Along with deep aortic wedging, the bidirectional bulge of the basal septum deforms and narrows the LVOT without affecting the virtual basal ring morphology.

467 Update on supra-annular sizing of transcatheter aortic valve prostheses in raphe-type bicuspid aortic valve disease according to the LIRA method

Abstract Aims Transcatheter Aortic Valve Replacement (TAVR) in patients with bicuspid aortic valve (BAV) still represents a challenge due to the peculiar anatomy and the lack of consensus for the optimal CT scan sizing method for prosthesis selection. Recent evidences have shown that transcatheter heart valve (THV) anchoring in BAV patients might occur at the raphe-level, known as the LIRA (Level of Implantation at the RAphe) plane. Furthermore, a novel supra-annular sizing method based on the measurement of the perimeter at the raphe-level (LIRA-method) was shown to be safe and effective in 20 consecutive BAV patients with severe aortic stenosis. The purpose of this study was to confirm the safety and the efficacy of the LIRA method in a larger study population. Methods and results the LIRA plane method was applied to all consecutive patients with raphe-type BAV disease between November 2018 to September 2021 in our centre. We prospectively sized TAVI prosthesis according to the manufacture recommendations on the basis of baseline CT scan perimeters at the LIRA plane. Post-procedural device success, defined according to Valve Academic Research Consortium-2 (VARC-2) criteria, was evaluated in the overall cohort. Forty-four patients were identified as having a raphe-type BAV disease at pre-TAVI CT scans. Mean patient age was 80 ± 6.2 years and 74% were males; median Society of Thoracic Surgeons (STS) predicted risk of mortality score was 4.3 (3.0–6.5). Three different BAV anatomies (36 patients with BAV type 1 with calcific raphe, 5 patients with BAV type 1 with fibrotic raphe, and 3 patients with BAV type 2) were implanted with different types of TAVI prostheses (6 Acurate Neo 2,16 Acurate Neo, 21 Core Valve Evolut R/Pro , 1 Lotus) sized prospectively according to the LIRA plane method. In all patients, there was a significant discrepancy between LIRA and virtual basal ring (VBR) measurements with LIRA plane perimeter smaller than VBR perimeter (mean perimeter LIRA 73.1 ± 8.3 mm vs. mean perimeter VBR 81.5 ± 6.6 mm; P &amp;lt; 0.001). The prostheses were sized according to the manufacture recommendations on the basis of the LIRA plane perimeter (diameter prosthesis implanted/diameter prosthesis according to LIRA plane = 1) (DPI/DP LIRA = 1) and significantly downsized according to the VBR perimeter (DPI/DP VBR 0.89; P &amp;lt; 0.001). The median prosthesis size was 25 mm (23–27). Pre-dilatation was frequently performed (86%) with a median balloon size of 20 mm (18–22), whereas post-dilatation was applied in 27% of the cases with a median balloon size of 23 mm (20–26). The LIRA plane method appeared to be highly successful (100% VARC-2 device success) with no procedural mortality, no valve migration, residual trivial/mild paravalvular leak with no cases of moderate-severe regurgitation and low transprosthetic gradient (residual mean gradient of 8.3 ± 3.5 mmHg) with no cases of mean gradient &amp;gt;20 mmHg pre-discharge. The rate of new pacemaker implantation was 9%. Conclusions Supra-annular sizing according to the LIRA plane method confirmed to be safe with a high device success in a larger study population. The application of the LIRA plane method might optimize TAVI prosthesis sizing in patients with raphe-type BAV disease.

701 ECMO assistance during TAVI in high-risk patient with recent COVID-19 pneumonia

Methods and resultsA 87 years old woman, with history of dyslipidemia and permanent Atrial Fibrillation, already undergone full SARS-CoV2 vaccination few months before, referred to our E.R. with complain of dyspnoea and chest pain. COVID-19 molecular test resulted positive and CT Scan of the chest confirmed the presence of several areas of ground-glass opacity and consolidation together with bilateral pleural effusion (right 6 cm with pulmonary atelectasis; left 2 cm), not requiring drainage. Moreover, it showed severe calcification of both the aortic valve and root. Transthoracic echocardiogram showed eccentric LV hypertrophy with diffuse hypokinesia (EF 20–25%), ectatic ascending aorta (45 mm) with severe LF-LG aortic stenosis (AVAi 0.19 cm2) and moderate regurgitation, moderate-severe mitral regurgitation. During hospitalization in the COVID-19 Unit, despite O2 therapy she experienced worsening of the respiratory status with concomitant pulmonary oedema, hypotension and acute kidney injury, requiring administration of i.v. dobutamine and high dose diuretics. After gradual stabilization and COVID-19 negativization on 10th molecular test, she was transferred to our Coronary Care Unit. Coronary angiography showed absence of significant stenoses in the main vessels. In the following days the patient underwent a new clinical deterioration with dyspnoea, hypotension (BP 85/50 mmHg), oliguria and ankle swelling, requiring Ventimask O2 therapy and Dobutamine infusion. Transtoracic echocardiogram confirmed EF of 25% with PASP 30 mmHg. We decided to perform a ‘Rescue’ TAVI procedure, facilitated by extra-corporeal cardiac and respiratory support. CT Angiography of the chest, performed with low-dose contrast injection under amines infusion, showed severly calcific aortic valve with large sizes of the ring (Virtual Basal Ring area 620 mm2, perimeter 91 mm), measures compatible with the largest sizes of TAVI prostheses. After Veno-Arterial Extracorporeal Membrane Oxygenation (ECMO) cannulation, we performed the implantation of a 34 mm Evolut R (Medtronic) TAVI prosthesis, post-dilated with 24 mm balloon for under-expansion due to massive calcification. During both self-expandable TAVI delivery and balloon inflation the patient underwent two phases of cardiac arrest, during which the ECMO flow provided a proper circulatory support.ConclusionsSince percutaneous valve replacement the patient’s recovery was fast with rapid ECMO removal and discontinuation of inotropic therapy. Few weeks after discharge, at first follow-up examination, the patient appeared asymptomatic, in excellent clinical conditions. 701 Figure

Pulmonary Autograft Sinus Muscular Inclusion: A Relative Contraindication for Ross Procedure

Muscular inclusion at the base of the right coronary sinus in aortic valves has previously been described by our group. It occurs due to crossing of the ventriculoaortic junction above the level of the virtual basal ring and aortic cusp insertion.1 This anatomic entity, however, has not been previously described in pulmonary valves. Herein, we are demonstrating that muscular inclusion at the base of the pulmonary valve sinus can also occur (Figure 1; blue arrows depict anterior pulmonary valve cusp; black arrows depict muscular inclusion of the anterior pulmonary valve sinus), but it is a subtle finding, and can hence be easily overlooked.

Embodiment and Performance in the Supernumerary Hand Illusion in Augmented Reality

In teleoperations, robots are generally used because related tasks are too dangerous, uncomfortable or impossible for humans to perform. When using augmented reality to control robotic limbs in such teleoperations, it is essential to understand how these extra virtual limbs are experienced. In particular, the relationship between the embodiment experience of the user and relevant outcomes such as task performance must be examined. In this article, we study the relationship between experienced embodiment of a supernumerary virtual arm that acts alongside a user’s two real arms, and their task performance in augmented reality. Specifically, we compare how well users can trace a virtual half ring placed just outside of personal space using their virtual arm in a condition where there is expected to be low embodiment (a floating disconnected hand) and a condition where there is expected to be high embodiment (a connected arm and hand). Embodiment is measured quantitatively through skin conductance response and qualitatively through ownership, agency, and self-location questionnaires. Performance is measured in terms of tracing precision. The results show positive correlations between subjective ownership and agency, and agency and performance, but no correlation between subjective or objective ownership and performance. Also, ownership ratings were low overall, while the agency ratings were significantly higher for the disconnected hand condition than the connected arm condition, as was performance. Notably, the presence of the virtual arm evoked incorrect expectations of the movement capabilities of the arm, which may have contributed to an overall preference for the unrealistic disconnected hand over the more realistic connected arm in this particular task. Our results imply that methods to increase performance in various teleoperations can indeed be found in the experience of embodiment: not necessarily directly through ownership, but through ownership mediated by agency.

Experimental and simulation study of fill-factor enhancement using a virtual guard ring in n+/p-well CMOS single-photon avalanche diodes

The use of a physical guard ring in CMOS single-photon avalanche diodes (SPADs) based on n + /(deep)p-well and p + /(deep)n-well structures is a common solution to control the electric field of the SPADs periphery and prevent the premature lateral breakdown. However, this leads to a decrease of the detection efficiency, i.e., the fill-factor, especially when the SPADs size is reduced. Our paper presents an experimental and simulation study on replacing the physical guard ring by a virtual guard ring to improve the fill-factor and the scalability of a n + / p-well SPAD implemented in 0.35-μm pin-photodiode CMOS technology. Accordingly, the optimization of the virtual guard ring and its superiority at downscaling are discussed, and the SPAD scalability in size with respect to the fill-factor is quantified in this technology.

Energy conserving ring cluster‐based routing protocol for wireless sensor network: A hybrid based model

AbstractThe recent advancement in WSNs has drawn its attentive toward number of researchers as it is supportive to the wide range of applications. During the routing mechanism in WSN, the tiny sensors powered with batteries can be expired soon. Number of solutions have been proceeded so far to resolve this issue, and the ring routing protocol is one among them. The ring routing protocol is an energy‐proficient mobile sink routing protocol that can be easily accessible and configures based on the virtual ring composition. Moreover, ring routing is a hierarchical routing protocol with a mobile sink in WSN that uses greedy geographic routing. In this research work, an energy‐aware ring routing protocol is developed based on the defined multi‐objective. Initially, the ring is constructed with a pre‐defined radius and the normal nodes now send data to the sink node via the constructed ring structure. More particularly, the nodes near the sink deplete faster than the other nodes and introduce overhead in terms of “energy consumption and packet delays.” When a ring node tends to exhaust, then its neighbor switches its role automatically, and this selection of the normal node as the ring node is accomplished optimally on the basis of the defined multi‐objectives like energy , distance between the ring node and the regular node and distance between network centers to regular node . As optimization has a key role in selecting the neighbors as the ring nodes, a new optimization model referred to as Moth Integrated Firefly Algorithm (MIFA) is introduced in this research work. The performance of the proposed model is compared over other conventional models with respect to throughput, energy dissipation, and transmission delay as well.

Aortic root anatomy after aortic valve reimplantation

ObjectiveDuring the last decade, special concerns have been raised about the anatomic relationships among the sinotubular junction, ventricular-aortic junction, and virtual basal ring to improve the results of root reconstruction. The aim of this study is to evaluate the in vivo anatomy of the aortic root after reimplantation with the Valsalva graft and the anatomic relationship between its components. MethodsWe analyzed 10 consecutive patients with tricuspid aortic valves who underwent reimplantation with the Valsalva graft between September and December 2019. Surgical clips were applied as markers at the level of proximal annular knots and at the distal reimplanted commissures on the neo-sinotubular junction. Electrocardiogram-gated computed tomography scan of the aortic root was performed. Coordinates of the markers were exported on a 3-dimensional modeling software, and the distances between the virtual basal ring and the Dacron graft basal landmarks were measured. ResultsThe mean heights of Dacron graft basal landmarks from virtual basal ring were right-left commissure 7.1 ± 5.1 mm; right sinus 4.7 ± 4.1 mm; right-noncoronary commissure 2.8 ± 2.2 mm; noncoronary sinus 1.4 ± 1.6 mm; left-noncoronary commissure 2.2 ± 2.3 mm; and left sinus 2.0 ± 0.9 mm. The mean planar distances of basal Dacron graft landmarks from virtual basal ring (thickness) were right-left commissure 5.3 ± 3.1 mm; right sinus 2.8 ± 1.4 mm; right-noncoronary commissure 2.2 ± 1.5 mm; noncoronary sinus 1.5 ± 1.5 mm; left-noncoronary commissure 1.3 ± 1.0 mm; and left sinus 3.4 ± 2.5 mm. ConclusionsAfter reimplantation, despite a complete dissection of the root, slight asymmetry of graft proximal seating exists. The inner annuloplasty is on the virtual basal ring, and the proximal edge of the Dacron graft is on the ventricular-aortic junction at a slightly different thickness and height along the annular circumference. At the level of the right sinus and left/right commissure, the Dacron graft is higher than the virtual basal ring and the relative wall thickness is increased. The annular stabilization is unaffected.

IoT Platform with Distributed Brokerson MQTT

Various wide-area Internet of Things services have been deployed. In most of these IoT services, a significant number of tiny data blocks are transferred across wide-area networks. Therefore, the transfer mechanisms should be simplified. One promising candidate for use as a transfer mechanism is MQ Telemetry Transport (MQTT). In this paper, an architecture for a distributed MQTT broker, referred to as a virtual ring approach, is proposed. This architecture complies with the IoT Data Exchange Platform, as discussed in ISO/IEC JTC 1/SC 41. The operations of this distributed broker architecture using a virtual ring network for real-time communication is also described, along with the superiority of the architecture based on a performance analysis using queuing models

Walking Speed Reliably Measures Clinically Significant Changes in Gait by Directional Deep Brain Stimulation.

Introduction: Although deep brain stimulation (DBS) often improves levodopa-responsive gait symptoms, robust therapies for gait dysfunction from Parkinson's disease (PD) remain a major unmet need. Walking speed could represent a simple, integrated tool to assess DBS efficacy but is often not examined systematically or quantitatively during DBS programming. Here we investigate the reliability and functional significance of changes in gait by directional DBS in the subthalamic nucleus.Methods: Nineteen patients underwent unilateral subthalamic nucleus DBS surgery with an eight-contact directional lead (1-3-3-1 configuration) in the most severely affected hemisphere. They arrived off dopaminergic medications >12 h preoperatively and for device activation 1 month after surgery. We measured a comfortable walking speed using an instrumented walkway with DBS off and at each of 10 stimulation configurations (six directional contacts, two virtual rings, and two circular rings) at the midpoint of the therapeutic window. Repeated measures of ANOVA contrasted preoperative vs. maximum and minimum walking speeds across DBS configurations during device activation. Intraclass correlation coefficients examined walking speed reliability across the four trials within each DBS configuration. We also investigated whether changes in walking speed related to modification of step length vs. cadence with a one-sample t-test.Results: Mean comfortable walking speed improved significantly with DBS on vs. both DBS off and minimum speeds with DBS on (p < 0.001, respectively). Pairwise comparisons showed no significant difference between DBS off and minimum comfortable walking speed with DBS on (p = 1.000). Intraclass correlations were ≥0.949 within each condition. Changes in comfortable walk speed were conferred primarily by changes in step length (p < 0.004).Conclusion: Acute assessment of walking speed is a reliable, clinically meaningful measure of gait function during DBS activation. Directional and circular unilateral subthalamic DBS in appropriate configurations elicit acute and clinically significant improvements in gait dysfunction related to PD. Next-generation directional DBS technologies have significant potential to enhance gait by individually tailoring stimulation parameters to optimize efficacy.

Harvested Energy Scavenging and Transfer capabilities in Opportunistic Ring Routing

Energy conservation has always been a prominent design goal for hierarchical routing protocols supporting sink mobility. Advertising the current position of mobile sink introduces control packet overhead which ultimately results in an increase in energy consumption and shorter network lifetime. Energy harvesting through ambient sources have enabled the utilization of rechargeable devices for Wireless Sensor Networks to perpetually remain operational. The modifications in the hierarchical structure of wireless sensor networks along with energy scavenging approaches could possibly minimize the control packet overhead and also provide a significant improvement in energy conservation. In this paper, we propose a novel Harvested Energy Scavenging and Transfer capabilities in Opportunistic Ring Routing protocol which uses a distinguishing approach of hybrid (ring + cluster) topology in which the network architecture is initially supported by the formation of a virtual ring structure and then a two-tier routing topology is used in the virtual ring as an overlay by grouping nodes into clusters. The rate of energy gain from solar harvesting and radio frequency transfer is the criterion for selecting cluster heads. The role of cluster heads is exploited to advertise the mobile sink current position as well as forward the aggregated data towards mobile sink using energy transfer based opportunistic routing. The simulation results reveal that our scheme considerably outperforms the existing benchmarks in terms of control packet overhead, energy conservation, network lifetime, packet delivery ratio and average end-end delay.

Scalable and efficient graph traversal on high-throughput cluster

Graph is one of the most important data structures in modern big data applications and is widely used in various fields. Among many graph algorithms, the Breadth-First Search (BFS) algorithm is a classic algorithm to solve the graph traversal problem and also the key kernel of Graph500 benchmark. On modern CPU architecture, the implementation of graph traversal on single-node systems has achieved significant improvement. However, due to the low resource utilization and high communications overhead, graph traversal on distributed clusters suffers from poor performance and energy inefficiency. High-throughput cluster (HTCs) adopt High-Throughput many-core architecture, which has the characteristics of high concurrency, strong real-time, and low-power consumption. In this work, we propose several techniques, including asynchronous virtual ring method, thread caching scheme and vertex ID reordering to solve above problems and improve BFS performance on HTCs. We systematically evaluate optimized BFS algorithm and achieve 249.74 giga-traversed edges per second (GTEPS) on 72 nodes (2880 cores) HTCs. Compared with results on Graph500 list, the optimized algorithm achieves the highest node efficiency under the same cluster scale and the performance shows weakly linear scalability as the number of cluster nodes increases. With regard to efficiency, the average performance on HTCs is 3.47 GTEPS/node, which is the best among CPU-based distributed systems on the November 2019 Graph500 list.

Aortic annulus rupture during transcatheter aortic valve implantation: complication prevention and management

Aortic annulus rupture is a dangerous complication of transcatheter aortic valve implantation, with an overall incidence of around 1%. Ruptures can be distinguished into supra-annular, involving injuries of the sinus of Valsalva and the sinotubular junction, annular, involving the fibrous portion of the aortic annulus, and sub-annular, located in the left ventricular outflow tract below the aortic valve cusp insertion. Annular rupture can be "contained", which usually evolves in aortic hematoma or pseudoaneurysm and rarely requires emergent cardiac surgery; or "non-contained", acutely evolving in hemopericardium with cardiac tamponade, often requiring emergent cardiac surgery and with an in-hospital mortality of 75%. Balloon-expandable oversizing and severe left ventricular outflow tract calcifications, especially under the left coronary cusp, are the most important risk factors for annular rupture. A careful computed tomography scan-based procedural planning is of paramount importance to reduce the risk of this complication. The presence and extension of left ventricular outflow tract calcifications, together with precise measurement of the virtual basal ring, should drive the operator to the right choice of prosthesis type and size in order to prevent this terrible complication.