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A theory of self-healing (SH) in metallized film capacitors (MFCs) is introduced. The interruption of the filamentary breakdown (BD) current in the thin dielectric insulation occurs when the thermally driven increase of the series impedance in the electrode metallization destabilizes the BD plasma arc. The interruption process can be described as a switching process which is self-induced by feedback via Joule heating. The theory is illustrated with an electric arc-like model for the BD current, coupled to the 2-D temperature-dependent RC transmission plane defined by the two metallization electrodes. A specific model realization is implemented in a multiphysics finite element method (FEM) simulation tool (COMSOL) and illustrated with a few results for electrodes with and without segmentation.

A theory to predict the reliability evolution and remaining useful lifetime (RUL) of technical devices in the framework of Fokker–Planck equations (FPE) is discussed and illustrated with examples. The FPE is a partial differential equation for the probability density in the space of aging model variables. This stochastic physics approach to prognostics is based on the mathematical equivalence of the FPE and Langevin equations covering, e.g., Brownian motion (BM) models with drift. Given an aging model, the FPE is an efficient framework for simulating the time dependent reliability, which is obtained from integration of the probability density in the acceptance region in condition space. Wear-out failures are associated with the probability flux out of the acceptance region through boundaries defined by end-of-life conditions. Chance failures can be included with sink terms in the FPE. Additional information gain by, e.g., condition monitoring (CM), can be considered by updating the probability density via Bayesian inference. The concept is useful if the deterministic part of the aging model can be formulated in terms of ordinary differential equations for aging variables, which requires a certain understanding of the physics of degradation and failure. To illustrate the concept, simulation results with own or commercial (here COMSOL Multiphysics) solvers for partial differential equations are presented for simple examples, including BM models with drift, stress–strength reliability, and battery aging.

High blood pressure (BP) is a major risk factor for cardiovascular disease (CVD). Consumption of dark chocolate, which is high in flavonoids that may reduce CVD risk, is an attractive intervention to reduce to BP. Additionally, the use of mobile health (mHealth) technologies (eg, telehealth, smartphones, and wearable devices) can improve outcomes in patients with CVD.

AbstractIn resting-state functional MRI (rs-fMRI), functional networks are assessed utilizing the temporal correlation between spontaneous blood oxygen level-dependent signal fluctuations of spatially remote brain regions. Recently, several groups have shown that temporal shifts are present in rs-fMRI maps in patients with cerebrovascular disease due to spatial differences in arterial arrival times, and that this can be exploited to map arrival times in the brain. This suggests that rs-fMRI connectivity mapping may be similarly sensitive to such temporal shifts, and that standard rs-fMRI analysis methods may fail to identify functional connectivity networks. To investigate this, we studied the default mode network (DMN) in Moyamoya disease patients and compared it with normal healthy volunteers. Our results show that using standard independent component analysis (ICA) and seed-based approaches, arterial arrival delays lead to inaccurate incomplete characterization of functional connectivity within the DMN in Moyamoya disease patients. Furthermore, we propose two techniques to correct these errors, for seed-based and ICA methods, respectively. Using these methods, we demonstrate that it is possible to mitigate the deleterious effects of arterial arrival time on the assessment of functional connectivity of the DMN. As these corrections have not been applied to the vast majority of >200 prior rs-fMRI studies in patients with cerebrovascular disease, we suggest that they be interpreted with great caution. Correction methods should be applied in any rs-fMRI connectivity study of subjects expected to have abnormally delayed arterial arrival times.

Introduction:Female sex is an established, non-modifiable risk factor for adverse outcomes in atrial fibrillation (AF) patients. Left atrial appendage occlusion (LAAO) has been shown to be generally safe and effective for stroke prevention in patients with AF. Data on sex-based outcomes with WATCHMAN FLX is lacking.Methods:WATCHMAN FLX patients from the National Cardiovascular Data Registry LAAO Registry between August 5th 2020 and March 31st 2021 were analyzed.Results:Women at baseline had a higher average CHA2DS2-VASc score, were more likely to have a history of transient ischemic attack, thromboembolic event, peripheral or carotid artery disease, fall risk, and chronic lung disease than men. Conversely, history of congestive heart failure, left ventricular dysfunction, hypertension, diabetes, vascular disease, abnormal renal function, cardiomyopathy, non-paroxysmal atrial fibrillation, myocardial infarction, prior cardiac interventions, alcohol use, antiplatelet medication use and non-steroidal anti-inflammatory drug use were all reduced in women compared to men. The early safety endpoint was similar between women and men (Table). At 45 days, unadjusted rates of major adverse events were higher in women than men mainly due to differences in major bleeding and pericardial effusion (Table). The risk of death was lower in women than men at 45 days. Rates of stroke, major vascular complications, systemic thromboembolism, myocardial infarction, and device-related thrombus were not significantly different between sexes. Adjusted outcomes will be available at the time of the presentation.Conclusions:In this national unselected cohort, there are significant sex-based differences in baseline characteristics and comorbidity burden. Women experienced more major adverse events after LAAO than men. Additional research to determine the underlying mechanisms of the increased risk in women and strategies for closing the gap between sexes are needed.

The popularity of fourth generation (4G) cellular communication technology, and the concurrent predominance of second (2G) and third generation (3G) systems have made multi-standard wireless transceivers a necessity. This paper describes the system level planning, the architectural design, and the VLSI implementation of a reconfigurable discrete-time ΔΣ ADC for a multi-standard 2G/3G/4G wireless receiver. We present an optimized switched-capacitor loop filter implementation that maximizes the achievable sampling rate by deploying an early regeneration of the quantizer. Reconfigurability is mainly realized at the architectural level by adapting the oversampling ratio and the quantizer resolution, depending on the mode, to achieve the required dynamic range. Implemented in a 130 nm CMOS technology, and occupying an area of 0.31 mm2, the modulator runs at a maximum sampling rate of 450 MHz. The ADC achieves 87 dB and 63 dB DR in a 100 kHz and 25 MHz bandwidth, respectively. The effective resolution ranges from 13.2 bit to 9.7 bit at a scalable power consumption between 3.4 mW and 56.7 mW from a single 1.2 V supply. An open loop reference buffer is embedded on-chip to generate the required reference voltage levels (without the need for external components) making the modulator suitable for fully integrated cellular transceivers.

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Macrophages predominate among the inflammatory cells in rejecting allografts. These innate immune cells, in addition to allospecific T cells, can damage cardiomyocytes directly.

Low levels of plasma adiponectin, an adipocytokine that possesses anti-inflammatory and antiatherogenic properties, frequently observed among obese subjects correlate with higher prevalence of several cardiovascular diseases. This study investigated whether adiponectin modulates allograft rejection in major histocompatibility complex class II-mismatched cardiac transplants.

Objective:Previous studies demonstrating a correlation between low shear stress (τ = 5-15 dyne/cm2) and experimental vein graft neointimal thickening (NIT) support the role of low τ in vein graft failure. However, a simple linear relationship between low τ and NIT would underestimate the degree of NIT evident in high-grade occlusive lesions of failing human vein grafts. In this study we used a new experimental model that maintains patency at low τ (< 2 dyne/cm2), to delineate possible deviations from linearity in the low τ → NIT hypothesis. Methods:Thirty-two New Zealand White rabbits underwent creation of a common carotid vein patch with a segment of ipsilateral external jugular vein. Very low τ was created in 13 patches by ligation of the distal common carotid artery, leaving the only outflow through a small muscular branch. Normal τ was created in 11 patches by leaving the common carotid artery outflow intact. High τ was created in eight patches by ligation of the contralateral common carotid artery. Six patches were harvested after 2 weeks for measurement of cell cycle entry by proliferating cell nuclear antigen (PCNA) immunohistochemistry. The remaining 26 patches were harvested after 4 weeks, perfusion fixed, and excised for morphometric analysis. Results:Mean blood flow and τ at implantation ranged from 0.5 to 41 mL/min and 0.07 to 15 dyne/cm2, respectively. At the time of harvest, 30 of 32 patches remained patent, and the artificially created aberrations in blood flow were maintained (range, 0.7-41 mL/min). After 2 weeks PCNA immunohistochemistry showed a significantly higher level of cell cycling in patches exposed to low τ (40 ± 5 vs 1.6 ± 0.3 PCNA-positive cells per high-power field; P<.001), which is equivalent to approximately 20% of the total cells present. In patches harvested after 4 weeks, NIT ranged from 42 to 328 μm and significantly correlated with mean τ at implantation. Patches with very low τ exhibited histologic characteristics similar to those of failing human bypass grafts, including laminar thrombus and flow-limiting luminal stenosis. The relationship between τ and NIT was nonlinear in that extremely low τ (< 2 dyne/cm2) resulted in NIT beyond that predicted by a simple linear correlation (P=.003). Conclusion:Extremely low τ (< 2 dyne/cm2) stimulates high rates of smooth muscle cellular proliferation in arterialized vein patches. NIT is accelerated in these regions of low τ far beyond that predicted by a simple linear model. The nonlinear nature of the cellular proliferative response and NIT at τ less than 2 dyne/cm2may explain the rapid progression of neointimal lesions in failing bypass grafts. (J Vasc Surg 2001;34:90-7.)

We investigate the statics, nucleation, and dynamics of stable kink-antikink pairs (KAP) in a one-dimensional, one-component reaction-diffusion equation with a piecewise linear nonlinearity. The stabilization of the KAP is due to the presence of a strongly nonlocal inhibitor. We find a saddle-node bifurcation of a metastable KAP with a separation proportional to In L, where L is the length of the sample. The KAP becomes globally stable at a characteristic separation proportional to √L. The nucleation of a KAP from the metastable uniform state differs from the case without nonlocality mainly by a change of the activation energy induced by the nonlocality. Furthermore, we investigate the dynamics of the stable KAP in the presence of an external driving force and a diluted density of pointlike impurities; in particular, we derive expressions for the mobility and the average elongation of the KAP.

Selective Laser Melting (SLM) was used to produce 3D-printed net shape NdFeB (Neodymium Iron Boron) permanent magnets that exhibit relatively large internal permanent magnetization structures, without exposure to any external magnetizing field. The macroscopic magnetization, M→(r→), does not create a significant magnetic stray field outside the as-produced sample, and is pole avoiding and solenoidal. The permanent magnetization can be detected via the stray field that appears after cutting the sample into pieces. From the field measurements it can be concluded that the magnetization is mainly in the 3D-printing planes which are parallel to M→(r→). Maximum magnetic flux densities of almost 80 mT are recorded 1 mm above the cut surfaces in the air. Dependencies of the effect on SLM process parameters, as well as on the sample size and shape are discussed. Although a deep understanding is still missing, a possible mechanism that may partly explain the formation of these self-organized macroscopic magnetization structures is proposed. The discovered effect may offer new routes for producing magnetized rare earth-transition metal (RE-TM) permanent magnets without using a magnetizer, and it shows that the SLM 3D-printing process can lead to new material behavior.

•Analytical expressions for Ragone plots (energy-power relations) and discharge efficiency-power relations are derived in the framework of endoreversible thermodynamics for ideal electrical and thermal energy storage systems.•The Ragone plots are equal to the efficiency-power relations for battery and for latent heat storage, but different for capacitor and sensible heat storage due to their limited intrinsic depth of discharge at constant power.•The discharge efficiency of the ideal sensible heat storage device has a local maximum at a finite power value.

Due to their excellent electrical insulation properties and processability, polymer materials are used in many electrical products. It is widely believed that space charge plays an important role for the electric field distribution, conduction, ageing, and electric breakdown of polymeric insulation. This paper reviews measurements and characteristics of space charge behavior which mainly determined by the pulsed electro-acoustic (PEA) measurement technique. Particular interests are the effects of the applied voltage, the electrodes, temperature, humidity, microstructure, additives, and filler materials on accumulation, distribution, transport, and the decay of space charge in polymeric materials. This review paper is to provide an overview on various space charge effects under different conditions, and also to summarize the information for polymeric materials with suppressed space charge and improved electrical behavior.

Drug eluting stents with durable polymers may be associated with hypersensitivity, delayed healing, and incomplete endothelialization, which may contribute to latevery late stent thrombosis and the need for prolonged dual antiplatelet therapy. Bioabsorbable polymers may facilitate stent healing, thus enhancing clinical safety. The SYNERGY stent is a thin-strut, platinum chromium metal alloy platform with an ultrathin bioabsorbable Poly(D,L-lactide-co-glycolide) abluminal everolimus-eluting polymer. We performed a multicenter, randomized controlled trial for regulatory approval to determine noninferiority of the SYNERGY stent to the durable polymer PROMUS Element Plus everolimus-eluting stent.