Intrinsic Conduction Research Articles

Excellent energy storage properties with ultrahigh Wrec in lead-free relaxor ferroelectrics of ternary Bi0.5Na0.5TiO3-SrTiO3-Bi0.5Li0.5TiO3 via multiple synergistic optimization

Advanced energy storage capacitors play important roles in modern power systems and electronic devices. Next-generation high/pulsed power capacitors will rely heavily on eco-friendly dielectric ceramics with high energy storage density (Wrec), high efficiency (η), wide work temperature range and stable charge-discharge ability, etc. Lead-free Bi0.5Na0.5TiO3 (BNT) based relaxor ferroelectric (RFE) ceramics are considered as one of the most promising candidates for energy storage capacitors. However, the application fields of them are greatly limited by their relatively low Wrec (generally <5 J/cm3). In this paper, excellent energy storage properties characterized by a great breakthrough in Wrec are achieved in a novel BNT system, (1-x)BNT-x(0.7SrTiO3-0.3Bi0.5Li0.5TiO3)+0.5 at.%Nb2O5 (x = 0, 0.1, 0.2, 0.3, 0.4), by synergistically constructing highly dynamic polar nanoregions (PNRs) and nanodomains, ultrafine grains (submicron size) and intrinsic conduction. Of great importance, the x = 0.4 ceramic exhibits an ultrahigh Wrec of 8.63 J/cm3 as well as a high efficiency (ƞ) of 89.6 % under a giant electric field of 520 kV/cm, due to coexistence of ultrahigh polarization difference (ΔP=Pmax −Pr) and high dielectric breakdown electric strength (Eb). Furthermore, excellent temperature stability (20−180 °C), frequency stability (1 − 500 Hz), and cycling stability (1 − 105 times) with the variation of Wrec < ±4 % and η < ±3 % are also found in the x = 0.4 ceramic. These results demonstrate that it is a very promising lead-free dielectric capacitor with enormous energy storage applications.

High frame rate speckle tracking echocardiography to visualize the mechanical activation sequence of the left ventricle

Abstract Background Cardiac arrhythmias are a known cause of morbidity and mortality, with catheter ablation being an effective treatment. In order to detect the focal source or the re-entrant circuit of the arrhythmia, i.e. the ablation target, current practice includes performing an electrophysiological study. This technique is invasive, with increased patient related risk and variable success rate. Conversely, echocardiography could be used to determine the correct ablation target. High frame rate (HFR) ultrasound has a temporal resolution adequately high to detect the onset of myocardial deformation and could assist the accurate localisation of the arrhythmia source. Purpose To test whether HFR speckle tracking echocardiography (STE) can be used to create cardiac mechanical activation maps. Methods 18 healthy volunteers (HV) (age 30±6y; 69 %males) and 12 heart failure patients treated with cardiac resynchronisation therapy (CRT) (age 69±10y; 75 %males) were included. All participants were scanned with a research HFR ultrasound scanner (∼849fps) and the 3 standard apical views were acquired. Patients were scanned with CRT on and after turning CRT off, in order to allow intrinsic ventricular conduction. Data from one CRT patient were acquired by temporarily altering the pacing pole of the CRT LV lead. All patients had a left bundle branch block (LBBB) pattern of native activation on the surface ECG. For each view, a manually placed contour was tracked during the cardiac cycle by a custom-made 2D HFR STE algorithm; the contours were divided in a standard 16 segment model and segmental strain rate (SR) curves were computed and used to measure the temporal distance between electrical and mechanical activation (i.e. distance between the beginning of QRS and the first positive to negative zero crossing in the SR curve). Finally, an activation map for each subject was created by placing the extracted timings in the middle of the corresponding segment of a bull’s-eye plot and interpolating values between them. Results Tracking was feasible in 94% of the segments; SR curves showed a physiological pattern (Fig. 1A). For the HV, mechanical activation started from mid anteroseptal (72%) or mid inferoseptal (28%) segment at 23±5ms, spreading to basal posterolateral segment at 49±8ms from the start of QRS, in all but one case, where activation ended at basal inferoseptal segment (Fig. 1B). During CRT off, septal wall was activated 31±9ms and lateral wall 74±20ms after the beginning of QRS (p&amp;lt;0.01) (Fig. 1C), whereas during CRT on, septal wall was activated 41±11ms and lateral wall 38±7ms after the beginning of QRS (p=0.3) (Fig. 1D). Changing the pacing pole of the LV lead in one CRT patient also changed the start of mechanical activation in the lateral wall (Fig. 2). Conclusion Our findings comply with left ventricular activation as described in the literature and show that HFR STE could be a useful tool in defining the ablation target for arrhythmia treatment.

Clinical outcomes of left bundle branch area pacing compared with biventricular pacing in patients with heart failure requiring cardiac resynchronization therapy: systematic review and meta-analysis

Abstract Background Biventricular pacing (BVP) is recommended from the most recent ESC guidelines as the first line pacing strategy in patients with heart failure (HF) that require cardiac resynchronization therapy (CRT). (1) Many studies have shown its beneficial effects regarding morbidity and mortality in this population. (2, 3) However, 10% of patients cannot be treated by BVP due to unsuitable coronary sinus vein, while 30-40% are non-responders to BVP and experience no benefit from this treatment.(4) Left bundle branch area pacing (LBBAP) is a new pacing modality (5) that can achieve narrow QRS and improve left ventricular function in patients with HF, by engaging the intrinsic conduction pathway of the heart. Also, it appears to have better results in electrical and mechanical synchrony compared with BVP. Purpose We conducted a systematic review and meta-analysis to compare the two pacing modalities in terms of hard clinical outcomes, in patients with heart failure that require CRT. Methods Medline, Embase, Cochrane Central Register of Controlled Trials and Web of Science databases were systematically searched for studies comparing LBBAP with BVP for CRT in patients with HF. Outcomes of interest were all-cause mortality, Heart Failure Hospitalizations (HFH) and New York Heart Association (NYHA) class improvement. Two independent investigators identified studies, extracted data, and assessed the risk of bias using the Cochrane Risk of Bias 2 tool for randomized clinical trials and the Newcastle-Ottawa-Scale for observational studies. Pairwise meta-analysis was conducted using random and fixed effects models. Risk Ratios (RRs) and weighted mean difference (WMD) with 95% confidence intervals (CIs) were used to report dichotomous and continuous variables respectively. Heterogeneity was assessed with the I² statistic. Results In total, 764 studies were retrieved and finally 9 trials with 992 individuals (365 in LBBAP and 627 in BVP group) were included in the analysis. The mean follow-up duration was 13 ± 5.82 months and the average procedural success rate in the LBBAP group was 89.8%. The baseline characteristics were similar between the two groups. Pooled analysis showed that the two methods had no difference in terms of all-cause mortality (RR:0.87 CI 95%:0.38 to 2.02; I²=0%; p=0.750, Figure 1) with 8 (2.4%) vs 17 (2.9%) events occurring in LBBAP and BVP group respectively. However, LBBAP was found to have significantly lower risk for HFH (RR:0.58 CI 95%:0.38 to 0.91; I²=0%; p=0.020, Figure 2A) and to achieve more improvement in NYHA class compared with BVP (WMD: -0.40, CI 95%: -0.68 to -0.12; I²=72%; p=0.005; Figure 2B). Conclusions To the best of our knowledge this is the first meta-analysis that assesses exclusively the clinical outcomes of LBBAP compared to BVP in such an important number of patients. LBBAP presents better outcomes in HFH and NYHA class improvement, but it has no difference in all-cause mortality in comparison with BVP.Figure 1.All-cause mortalityFigure 2.A.HFH B.NYHA class improvement

Linear and symmetric synaptic weight update characteristics in van der Waals heterostructure transistors based on 2D In4/3P2Se6 barrier layer

Two-dimensional van der Waals heterostructures with fast-switching speed and ultra-low power consumption are promising building blocks for artificial synaptic devices (ASD) that aim to solve problems faced by traditional computing. However, the nonlinearity and asymmetry of synaptic weight updates in artificial synapses have hindered the achievement of high image classification accuracy in most reported neuromorphic networks. Here, we develop a nonvolatile MoS2/In4/3P2Se6/graphene ASD with excellent performance. Due to the intrinsic low conduction band offset (0.86 eV) of MoS2/In4/3P2Se6, the vdW heterostructure device exhibits an ultra-large storage window of 71.2 V at ±40 V back-gate sweep, a low nonlinear factor of 0.014/0.042, and a low asymmetry factor at 0.028. Additionally, the device exhibits synaptic behaviors including excitatory postsynaptic current, pair-pulse facilitation, and important “learning-experience” synaptic function under electrical and optical stimulation. This work indicates that In4/3P2Se6 provides remarkable opportunities for band alignment-related applications and can facilitate ongoing research of neuromorphic functional electronics.

Catheter-induced right bundle branch block: Practical implications for the cardiac electrophysiologist.

The right bundle branch (RBB), due to its endocardial course, is susceptible to traumatic block caused by "bumping" during right-heart catheterization. In the era of cardiac electrophysiology, catheter-induced RBB block (CI-RBBB) has become a common phenomenon observed during electrophysiological studies and catheter ablation procedures. While typically transient, it may persist for the entire procedure time. Compared to pre-existing RBBB, the transient nature of CI-RBBB allows for comparative analysis relative to the baseline rhythm. Furthermore, unlike functional RBBB, it occurs at similar heart rates, making the comparison of conduction intervals more reliable. While CI-RBBB can provide valuable diagnostic information in various conditions, it is often overlooked by cardiac electrophysiologists. Though it is usually a benign and self-limiting conduction defect, it may occasionally lead to diagnostic difficulties, pitfalls, or undesired consequences. Avoidance of CI-RBBB is advised in the presence of baseline complete left bundle branch block and when approaching arrhythmic substrates linked to the right His-Purkinje-System, such as fasciculo-ventricular pathways, bundle branch reentry, and right-Purkinje focal ventricular arrhythmias. This article aims to provide a comprehensive practical review of the electrophysiological phenomena related to CI-RBBB and its impact on the intrinsic conduction system and various arrhythmic substrates.

Adaptive versus conventional cardiac resynchronisation therapy in patients with heart failure (AdaptResponse): a global, prospective, randomised controlled trial

Continuous automatic optimisation of cardiac resynchronisation therapy (CRT), stimulating only the left ventricle to fuse with intrinsic right bundle conduction (synchronised left ventricular stimulation), might offer better outcomes than conventional CRT in patients with heart failure, left bundle branch block, and normal atrioventricular conduction. This study aimed to compare clinical outcomes of adaptive CRT versus conventional CRT in patients with heart failure with intact atrioventricular conduction and left bundle branch block. This global, prospective, randomised controlled trial was done in 227 hospitals in 27 countries across Asia, Australia, Europe, and North America. Eligible patients were aged 18 years or older with class 2-4 heart failure, an ejection fraction of 35% or less, left bundle branch block with QRS duration of 140 ms or more (male patients) or 130 ms or more (female patients), and a baseline PR interval 200 ms or less. Patients were randomly assigned (1:1) via block permutation to adaptive CRT (an algorithm providing synchronised left ventricular stimulation) or conventional biventricular CRT using a device programmer. All patients received device programming but were masked until procedures were completed. Site staff were not masked to group assignment. The primary outcome was a composite of all-cause death or intervention for heart failure decompensation and was assessed in the intention-to-treat population. Safety events were collected and reported in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT02205359, and is closed to accrual. Between Aug 5, 2014, and Jan 31, 2019, of 3797 patients enrolled, 3617 (95·3%) were randomly assigned (1810 to adaptive CRT and 1807 to conventional CRT). The futility boundary was crossed at the third interim analysis on June 23, 2022, when the decision was made to stop the trial early. 1568 (43·4%) of 3617 patients were female and 2049 (56·6%) were male. Median follow-up was 59·0 months (IQR 45-72). A primary outcome event occurred in 430 of 1810 patients (Kaplan-Meier occurrence rate 23·5% [95% CI 21·3-25·5] at 60 months) in the adaptive CRT group and in 470 of 1807 patients (25·7% [23·5-27·8] at 60 months) in the conventional CRT group (hazard ratio 0·89, 95% CI 0·78-1·01; p=0·077). System-related adverse events were reported in 452 (25·0%) of 1810 patients in the adaptive CRT group and 440 (24·3%) of 1807 patients in the conventional CRT group. Compared with conventional CRT, adaptive CRT did not significantly reduce the incidence of all-cause death or intervention for heart failure decompensation in the included population of patients with heart failure, left bundle branch block, and intact AV conduction. Death and heart failure decompensation rates were low with both CRT therapies, suggesting a greater response to CRT occurred in this population than in patients in previous trials. Medtronic.

Electrical Synchrony Optimization for Left Bundle Branch Area Pacing in Patients With Bradycardia and Heart Failure

Left bundle branch area pacing (LBBAP) has emerged as a promising physiological pacing modality. This study was designed to investigate the acute impact of the atrioventricular delay (AVD) on cardiac electrical characteristics and identify an optimal range of AVDs for LBBAP to achieve electrical atrioventricular and interventricular synchrony. Patients indicated for ventricular or biventricular pacing were studied during routine follow-ups at least 3months after LBBAP implantation. Patients were excluded if they had a complete AV block or persistent atrial fibrillation. AVD was programed from 40 to 240ms or until intrinsic conduction occurred. Optimal AVD was determined by the electrocardiography criteria, including QRS duration, reduced R-wave in lead V1, reduced notching or slurring in lateral leads, and more desirable precordial QRS transition. A total of 38 patients (age 68.7 ± 10.3years; 16 male (42%); 18 dual-chamber pacemakers and 20 cardiac resynchronization therapy devices; average follow-up period 15.1 ± 10.2months) were included. The fusion of LBBAP and intrinsic right ventricular conduction occurred in 21 patients with corresponding optimal AVD determined. A great proportion (∼85%) of the optimal AVDs ranged from 50% to 80% of the observed atrium-to-left bundle branch-sensing (A-LBBS) intervals. The linear correlation between the optimal AVD and corresponding A-LBBS interval (optimal AVD=0.84×[A-LBSs interval] - 36ms) produced R=0.86 and p <0.0001. In conclusion, AVD selection during LBBAP greatly impacted the ventricular electrical characteristics and the optimal AVD was linearly correlated with the corresponding A-LBBS interval.

Effects of Cu, Zn Doping on the Structural, Electronic, and Optical Properties of α-Ga2O3: First-Principles Calculations.

The intrinsic n-type conduction in Gallium oxides (Ga2O3) seriously hinders its potential optoelectronic applications. Pursuing p-type conductivity is of longstanding research interest for Ga2O3, where the Cu- and Zn-dopants serve as promising candidates in monoclinic β-Ga2O3. However, the theoretical band structure calculations of Cu- and Zn-doped in the allotrope α-Ga2O3 phase are rare, which is of focus in the present study based on first-principles density functional theory calculations with the Perdew-Burke-Ernzerhof functional under the generalized gradient approximation. Our results unfold the predominant Cu1+ and Zn2+ oxidation states as well as the type and locations of impurity bands that promote the p-type conductivity therein. Furthermore, the optical calculations of absorption coefficients demonstrate that foreign Cu and Zn dopants induce the migration of ultraviolet light to the visible-infrared region, which can be associated with the induced impurity 3d orbitals of Cu- and Zn-doped α-Ga2O3 near the Fermi level observed from electronic structure. Our work may provide theoretical guidance for designing p-type conductivity and innovative α-Ga2O3-based optoelectronic devices.

Enhanced thermoelectric performance of MoS2-Bi2S3 nanocomposites via low energy carrier filtering effect

Layered MoS2 (Molybdenum disulphide), an important transition metal dichalcogenide for energy conversion application due to intrinsic low thermal conduction and attractive functional properties. Here, we report on the hydrothermally prepared MoS2/Bi2S3 nanocomposites for mid-temperature thermoelectric applications. X-ray photo electron Spectroscopy reveals the change in fermi level of nanocomposites with Bi incorporation and oxidation states of the elements. High-Resolution Transmission Electron Microscope (HR-TEM) clearly indicates the formation of MoS2 nanosheets and Bi2S3 nano wires with the presence of interfaces. The interfacial effect greatly improved the thermoelectric power factor of 900 nW/mK2, which is nearly 8 times higher than pure MoS2.

Simultaneously realizing ultrahigh energy storage density and efficiency in BaTiO3-based dielectric ceramics by creating highly dynamic polar nanoregions and intrinsic conduction

Nowadays, it is urgent to explore advanced and eco-friendly energy storage capacitors based on lead-free relaxor ferroelectric (RFE) ceramics in order to meet the ever-increasing requirements in pulsed power systems. BaTiO3 (BT)-based RFE ceramics are considered as ones of the best high-temperature energy storage materials due to their good thermal stability. However, relatively low recoverable energy storage density (Wrec<5 J/cm3) has been a key bottleneck restricting the practical applications of them. Here, a novel strategy is proposed to create highly dynamic PNRs and the intrinsic conduction by introducing Bi(M1-0.015xTa0.015x)O3+0.015x (BMO-Ta, M=Mg2/3Ta1/3) to BT matrix. As a consequence, the designed (1-x)BT-x(BMO-Ta) ceramics exhibit dramatically enhanced energy storage properties including ultrahigh Wrec and efficiency (η), because of the coexistence of very slim polarization hysteresis (P-E) loops, large polarization difference (ΔP) and giant dielectric breakdown electric strength (Eb). Wrec and η of the x=0.25 ceramic reach up to 9.03 J/cm3 and 95.2% under 720 kV/cm, respectively. Furthermore, it shows excellent temperature/frequency/cycling stability over a wide range of 20−200 °C, 1−500 Hz and 1−3.3 × 105 cycles, respectively (the variations of Wrec and η are < 3% and < 4%, respectively). The findings in this paper not only indicate excellent comprehensive properties achieved in the novel (1-x)BT-x(BMO-Ta) system, but also provide an effective approach to explore advanced energy storage capacitors in other lead-free ceramic systems.

Conduction characteristics of n-InAs/n-GaAs heterojunctions with misfit dislocations

We investigated the transport properties of an n-InAs/n-GaAs heterojunction, where misfit dislocations are confined at the hetero-interface by forming a misfit dislocation network. The electric current I across the interface from n-InAs to n-GaAs was measured as a function of applied voltage V a. I is strongly suppressed at up to V a ∼ 1.0 V which is larger than the intrinsic conduction band offset between InAs and GaAs.I increases exponentially at low and high V a (=0.0–0.5 and 1.0–1.2 V), while the increase of I is relatively moderate at intermediate voltage V a (=0.5–1.0 V). We theoretically evaluated the I–V a characteristics of the n-InAs/n-GaAs heterojunction by using the thermionic-field emission model and examined the effects of the interface states due to the misfit dislocations. The comparison of the calculated results with the experimental data indicates the existence of acceptor-like interface states in the band gap of GaAs.

Long term conservation of electrical synchrony by multipoint pacing with dynamic atrioventricular delays

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Abbott. Introduction Automatic adjustment of atrioventricular delay (AVD) with SyncAV has been shown to improve electrical synchronization. However, the long term effects of SyncAV optimization on electrical synchrony are unknown. Purpose Evaluate the effect of SyncAV programming on 6-month (6mo) QRS duration during biventricular (BiV) and left ventricle only MultiPoint Pacing (MPP). Methods Patients with LBBB and QRS duration (QRSd) ≥ 150 ms scheduled for CRT-P/D device implantation with quadripolar LV lead were enrolled in this prospective study. QRSd was measured post-implant from 12-lead surface ECG by blinded experts during the following pacing modes: intrinsic conduction, MPP (MPP=RV+LV1+LV2) and LV-only MPP (LVMPP=LV1+LV2). For each mode, SyncAV was enabled (e.g. MPP+SyncAV) with the patient-tailored SyncAV offset that minimized QRSd. Patients were then randomized 1:1 to receive MPP+SyncAV or LVMPP+SyncAV with the optimal offset identified at implant, and QRSd was re-evaluated at the 6mo follow-up. Results Fifty-nine patients (72% male, 41% ischemic, 26% ejection fraction, 166 ms intrinsic QRSd) completed device implant and QRSd assessment. Relative to intrinsic conduction at implant, the MPP+SyncAV group (n=30) had a QRSd reduction of 26% at implant (162 to 122 ms, p&amp;lt;0.001), and 20% at 6mo (162 to 130 ms, p&amp;lt;0.001). The LVMPP+SyncAV group (n=29) had a QRSd reduction of 24% at implant (165 to 128 ms, p&amp;lt;0.001), and 15% at 6mo (165 to 140 ms, p&amp;lt;0.001). In the MPP+SyncAV group, 28/30 (93%) of patients had more than 10% reduction in QRSd with respect to intrinsic at implant, with 27/30 (90%) maintaining this trend at 6 mo follow up. With LVMPP+SyncAV pacing, only 25/29 (86%) of patients had more than 10% reduction in QRSd with respect to intrinsic at implant, and this reduced to 18/29 (62%) maintaining this trend at 6 mo follow up. Conclusion MPP combined with SyncAV significantly improved acute electrical synchrony at implant in CRT patients with LBBB, as assessed by QRSd reduction. Significant QRSd reduction was maintained at 6 months post-implant by both biventricular and LV-only MPP configurations.

Left bundle brunch pacing versus conventional right ventricular pacing in patients with bradycardia and conduction system disorders: a systematic review and meta-analysis

Abstract Funding Acknowledgements Type of funding sources: None. Background Right Ventricular Pacing (RVP) is well established as the widely accepted pacing method. However, its effects in ventricular function can be detrimental, causing electrical and mechanical dysynchrony and potential LVEF impairment. Left Bundle Branch Pacing (LBBP) is a new pacing strategy that appears to have better results preserving left ventricular function, by directly engaging the intrinsic conduction pathway of the heart. Purpose The aim of this systematic review and meta-analysis is to compare the safety and efficacy of the two pacing methods (LBBP and RVP) in patients suffering from bradyarrhythmia and conduction system disorders. Methods Medline, Embase and Pubmed databases were searched for studies comparing LBBP with RVP. Outcomes were QRSd (QRS duration), ventricular mechanical synchrony, LVEF changes, and Heart Failure Hospitalizations (HFH) to assess the efficacy, lead properties and complications to assess the safety. Two independent reviewers identified studies, extracted data, and assessed the risk of bias using the Cochrane Risk of Bias 2 tool for randomized clinical trials and the Newcastle-Ottawa-Scale for observational studies. Pairwise meta-analysis was conducted using random and fixed effects models. Risk Ratios (RRs) and weighted and standard mean difference (WMD, SMD) with 95% confidence intervals (CIs) were used to report dichotomous and continuous variables respectively. Heterogeneity was assessed with the I² statistic. Results 1318 articles were identified, and finally 25 trials with 4250 patients (2127 LBBP and 2123 RVP) were included in the analysis. Pooled analyses verified that QRSd is shorter in LBBP group both at implantation (WMD:-32.32, CI 95%:-35.18 to -29.45; I²=88%; P&amp;lt;.001) and at Follow Up (WMD: -32.20, CI 95%: -40.70 to -23.71; I²=92%; P&amp;lt;.001) and LBBP succeeded better interventricular mechanical synchrony (SMD:-2.04, CI 95%:-2.32 to -1.76; I²=21%; P&amp;lt;.001) than RVP. Intraventricular mechanical synchrony was also significantly better in LBBP vs RVP independently of the way of measurement in each study (SMD:-1.77, CI 95%:-2.45 to -1.09; I²=90%; P&amp;lt;.001) and in the subgroup analysis of the studies that implemented the same way of measurement (P&amp;lt;.001; I²=26%). LVEF alteration was not significant in the LBBP compared to native (P=.68; I²=52%), while in the RVP group showed a significant reduction (P&amp;lt;.001; I²=51%). LBBP showed, significantly better results in HFH (P&amp;lt;.001; I²=0%) and achieved similar pacing thresholds (P=.86) and higher R wave amplitudes (P&amp;lt;.05) than RVP while lead related complications had no difference between the two groups (LBBP=1.90% vs RVP=1.72%; P=0.71). Conclusions To our knowledge this is the first meta-analysis that assess the safety and efficacy of LBBP in such an important number of patients. LBBP preserves ventricular electrical and mechanical synchrony, shows a reduction in HFH compared to RVP and has excellent pacing parameters, without compromising safety.

Investigation of the Effect of Double-Filler Atoms on the Thermoelectric Properties of Ce-YbCo4Sb12.

Skutterudite compounds have been studied as potential thermoelectric materials due to their high thermoelectric efficiency, which makes them attractive candidates for applications in thermoelectric power generation. In this study, the effects of double-filling on the thermoelectric properties of the CexYb0.2-xCo4Sb12 skutterudite material system were investigated through the process of melt spinning and spark plasma sintering (SPS). By replacing Yb with Ce, the carrier concentration was compensated for by the extra electron from Ce donors, leading to optimized electrical conductivity, Seebeck coefficient, and power factor of the CexYb0.2-xCo4Sb12 system. However, at high temperatures, the power factor showed a downturn due to bipolar conduction in the intrinsic conduction regime. The lattice thermal conductivity of the CexYb0.2-xCo4Sb12 skutterudite system was clearly suppressed in the range between 0.025 and 0.1 for Ce content, due to the introduction of the dual phonon scattering center from Ce and Yb fillers. The highest ZT value of 1.15 at 750 K was achieved for the Ce0.05Yb0.15Co4Sb12 sample. The thermoelectric properties could be further improved by controlling the secondary phase formation of CoSb2 in this double-filled skutterudite system.

The influence of S[sbnd]O anion groups of organic/inorganic additives in rechargeability of zinc-air batteries

A number of difficulties on the zinc surface, including dendrites, passivation, shape change, and corrosion, result in insufficient electrochemical performance. Additives having an SO anion group incorporated into organic/inorganic atoms offer varied charge distributions of molecules that may be effective in resolving problems. Four additives containing the SO anion group, such as 4-Morpholinepropanesulfonic acid (MOPS, organic) and Na2S2O3, Na2SO3, and Na2SO4 (inorganic), reveal that 0.33 % (v/v) 1 M Na2SO4/6 M KOH is the most effective electrolyte due to its good Zn-deposition/dissolution. The maximal specific capacity of 818 mAhg−1 at 50 mAcm−2 (material utilization of 99.8 % based on the value of 820 mAhg−1) is compared to 806 mAhg−1 for the electrolyte-free additive. The galvanostatic charge-discharge cycles demonstrate excellent and stable performance without any fluctuations with the lower voltage gap (1.07 V) for Na2SO4/KOH at 50 mAcm−2 for >100 h, which is significantly lower than 6 M KOH at around 1.2 V. (1.4 V). DFT analyses demonstrate that Na2SO4 with the minimum energy gap (higher intrinsic conduction) are effective additives. As an organic additive, MOPS/KOH demonstrates an exceptional discharge capacity, but weak Zn-deposition/dissolution was seen due to the greatest energy gap, which resulted in less charge transfer interaction within the molecule.

PO-02-014 IMPACT OF RIGHT VENTRICULAR ELECTRICAL ACTIVATION (INTRINSIC AND PACED) IN HEART FAILURE PATIENTS WITH LBBB

The appropriately timed incorporation of the intrinsic right bundle branch (RBB) conduction during biventricular (RV & LV) pacing – “triple fusion”- may improve electrical resynchronization and response to CRT. However, the relative contribution of these wavefronts, optimal programming, and impact upon left ventricular activation remains poorly understood. To characterize intrinsic RBB and paced RV activation in heart failure patients with LBBB. CRT Patients with Strauss-type LBBB were studied. Right ventricular electrical activation was estimated from the onset of the r wave to the nadir of the S wave (rS interval) in leads V1 and V2. QRS duration was taken as the earliest onset to the terminal deflection in any lead. Paced QRS was measured during RV only pacing and nominal BiV (BiVNom; paced and sensed AV delay of 140/110 ms). The optimal AV delay was determined by the narrowest QRS duration achieved during simultaneous BiV pacing (BiVOpt) while adjusting the paced AV delay from 60% to 95% of the PR interval (in increments of 5%). This protocol was repeated while withholding RV pacing (LV-onlyOpt). All measurements were performed in each patient. Thirty patients (53% Male, 33% ICM, 68±8 yrs, EF 24±7%, qRV 25±8 ms, qLV 123±21 ms, and QRSd 170±18 ms) were evaluated. The PR interval was 208±39 ms (range 117-328 ms). The qlV/ QRS was 73±9%, indicating optimized LV lead position. Compared to BiVNom, BiVOpt was achieved at longer AVD (80±7% vs 56±7% of PR interval) but resulted in more rapid RBB electrical activation (59±14 ms vs 90±20 ms) and narrower QRS duration (130±13 ms vs 146±16 ms); all P < 0.05 vs BiVNom. Withholding RV pacing (LV-onlyOpt) did not impact RBB activation or AV delay programming compared to BiVOpt, but still reduced QRS duration compared to BiVNom (139±14 ms vs 146±16 ms; P<0.05). Incorporation of RV pacing during biventricular pacing with longer AVD programming facilitates intrinsic RBB conduction to improve electrical resynchronization without committing the LV to this wavefront.

Structural, elemental, and electrical conduction properties of corundum-type Mg2Co2Nb2O9

ABSTRACT is a new member of the corundum-type family. Its crystal structure is trigonal with space group . and ions share the A-site with fifty-fifty occupancy. In , exhibits a 2 + oxidation state, whereas shows a reduction in the charge state from 5 + to 4 + due to the presence of vacancy-trapped electrons in dimmer. The conductivity spectra analysis in view of various transport models states that overlapping large polaron tunneling is the predominant transport process (polaron radius 10.65 Å) in the low-temperature range (303-473 K), while for the high-temperature range (573-673 K), the conduction is intrinsic, and the carriers are primarily small polarons. The proximity between optical bandgap (∼1.60 eV) and conduction activation energy (1.64 eV) is due to the formation of intermediate energy bands near the Fermi level and their participation in high-temperature intrinsic conduction.

Ventricular conduction abnormality in patients with mild to moderate cardiomyopathy.

In mild-to-moderate cardiomyopathy, cardiac resynchronization therapy (CRT) is indicated in patients with high burden of right ventricular pacing but not in those with intrinsic ventricular conduction abnormalities. We hypothesized that CRT positively impacts outcomes of patients with intrinsic ventricular conduction delay and left ventricular ejection fraction (LVEF) of 36%-50%. Of 18 003 patients with LVEF ≤ 50%, 5966 (33%) patients had mild-to-moderate cardiomyopathy, of whom 1741 (29%) have a QRS duration ≥120 ms. Patients were followed to the endpoints of death and heart failure (HF) hospitalization. Outcomes were compared between patients with narrow versus wide QRS. Of the 1741 patients with mild-to-moderate cardiomyopathy and wide QRS duration, only 68 (4%) were implanted with a CRT device. Over a median follow-up of 3.35 years, 849 (51%) died and 1004 (58%) had a HF hospitalization. The adjusted risk of death (hazard ratio (HR) = 1.11, p = 0.046) and of death or HF hospitalization (HR = 1.10, p = 0.037) were significantly higher in patients with wide versus narrow QRS duration. In patients with wide QRS complex, CRT was associated with reduction in the adjusted risk of death (HR = 0.47, p = 0.020) and of death or HF hospitalization (HR = 0.58, p = 0.008). Patients with mild-to-moderate cardiomyopathy and wide QRS duration are rarely implanted with CRT devices and have worse outcomes compared to those with narrow QRS. Randomized trials are needed to examine if CRT has salutary effects in this population.

Sulfonic-Pendent Vinylene-Linked Covalent Organic Frameworks Enabling Benchmark Potential in Advanced Energy.

Both proton exchange membrane fuel cells and uranium-based nuclear techniques represent two green and advanced energies. However, both of them still face some intractable scientific and industrial problems. For the former, established proton-conduction materials always suffer one or another defect such as low proton conductivity, high activation energy, bad durability, or just small-scale product; while for the later, there still lacks available adsorbent to selectively recover of UO2 2+ from concentrated nitric acid (>1M) during the spent fuel reprocessing due to the deactivation of the adsorption site or the decomposition of adsorbent under such rigorous conditions. It is found that the above two issues can be well solved by the construction of sulfonic-pendent vinylene-linked covalent organic frameworks (COFs), since these COFs contain abundant sulfonic units for both intrinsic proton conduction and UO2 2+ capture through strong coordination fixation and vinylene linkage that enhances the stability up to 12M nitric acid (one of the best materials surviving in 12M HNO3 ).

Differences in Electrical Delay Between the Mid-septum and Apex with the Right Ventricular Lead: Novel Implications for Pacemaker Sensing.

Ventricular sensing relies on the analysis of a local intracardiac electrogram in reference to the QRS on the surface electrocardiogram. If both signals do not coincide in time, there is a delay in sensing intrinsic ventricular activity. We evaluated possible differences in the electrical delay between the mid-septum and apex as determined by the right ventricular (RV) lead position using a pacing system analyzer (PSA) during conventional pacemaker implantation. Patients without significant heart disease and intrinsic atrioventricular conduction underwent their first Medtronic (Minneapolis, MN, USA) or Abbott (Chicago, IL, USA) dual-chamber pacemaker implantation with the RV lead first positioned at the apex and then subsequently at the mid-septum. Real-time ventricular sensing data were obtained through PSA to determine the electrical delay Q-VS value as the time difference between the QRS and the released RV-sensed event marker "VS." Among 212 patients, 139 had narrow QRS and 73 had complete right bundle branch block (RBBB). Overall, both narrow QRS and RBBB patients exhibited shorter Q-VS lengths at the mid-septum compared to the apex (50.4 ± 24.2 ms and 66.7 ± 32.3 ms vs. 63.9 ± 27.6 ms and 71.7 ± 32.2 ms; P < .0001 and P < .001, respectively). The Q-VS in patients with Abbott devices was significantly shorter compared to that in patients with Medtronic devices at both the mid-septum and the apex in both patient groups (P < .0001). In conclusion, RV lead positioning at the mid-septum is associated with a shorter electrical delay compared to positioning at the apex in both narrow QRS and RBBB patients.