2,601 research outputs found
Fusion pacing with biventricular, left ventricular-only and multipoint pacing in cardiac resynchronisation therapy: Latest evidence and strategies for use
Despite advances in the field of cardiac resynchronisation therapy (CRT), response rates and durability of therapy remain relatively static. Optimising device timing intervals may be the most common modifiable factor influencing CRT efficacy after implantation. This review addresses the concept of fusion pacing as a method for improving patient outcomes with CRT. Fusion pacing describes the delivery of CRT pacing with a programming strategy to preserve intrinsic atrioventricular (AV) conduction and ventricular activation via the right bundle branch. Several methods have been assessed to achieve fusion pacing. QRS complex duration (QRSd) shortening with CRT is associated with improved clinical response. Dynamic algorithm-based optimisation targeting narrowest QRSd in patients with intact AV conduction has shown promise in people with heart failure with left bundle branch block. Individualised dynamic programming achieving fusion may achieve the greatest magnitude of electrical synchrony, measured by QRSd narrowing
Wettability versus roughness of engineering surfaces
Wetting of real engineering surfaces occurs in many industrial applications (liquid coating, lubrication, printing, painting, ...). Forced and natural wetting can be beneficial in many cases, providing lubrication and therefore reducing friction and wear. However the wettability of surfaces can be strongly affected by surface roughness. This influence can be very significant for static and dynamic wetting [1]. In this paper authors experimentally investigate the roughness influence on contact angle measurements and propose a simple model combining Wenzel and Cassie-Baxter theories with simple 2D roughness profile analysis. The modelling approach is applied to real homogeneous anisotropic surfaces, manufactured on a wide range of engineering materials including aluminium alloy, iron alloy, copper, ceramic, plastic (poly-methylmethacrylate: PMMA) and titanium alloy
Noninvasive electrocardiographic imaging of dynamic atrioventricular delay programming in a patient with left bundle branch block
Introduction
The response to cardiac resynchronization therapy (CRT) is determined by various factors, including left ventricular (LV) lead location, atrioventricular (AV) delay, and inter-/intraventricular delays. Advances in quadripolar lead technology and device algorithms have improved patient response, yet selection of optimal settings remains challenging. Studies have shown acute improvement in electrical synchrony with manual AV optimization by fusion optimized intervals1,2; automated device algorithms, for example AdaptivCRT (Medtronic, Minneapolis, MN),3 SmartDelay (Boston Scientific, Marlborough, MA),4 and SyncAVTM (Abbott, Sylmar, CA)5; and pacing from multiple LV lead electrodes with MultiPoint Pacing (MPP).6,7 The aim of this clinical case report was to evaluate the acute benefits of SyncAV Plus in the new-generation, Bluetooth-enabled GallantTM CRT device (Abbott, Sylmar, CA). SyncAV Plus continually programs the paced AV delay shorter than the intrinsic PR interval by a programmable offset (% of PR duration) to synchronize intrinsic and ventricular paced activation wavefronts. Twelve-lead electrocardiogram (ECG) and noninvasive electrocardiographic imaging (ECGi) epicardial mapping analyses were performed to characterize the impact of SyncAV Plus on electrical synchrony during a range of CRT programming strategies, including biventricular (BiV) pacing, MPP, LV-only pacing, and LV-only pacing with MPP
Manifolds with almost nonnegative curvature operator and principal bundles
We study manifolds with almost nonnegative curvature operator (ANCO) and
provide first examples of closed simply connected ANCO mannifolds that do not
admit nonnegative curvature operator
Effect of nearest neighbor repulsion on the low frequency phase diagram of a quarter-filled Hubbard-Holstein chain
We have studied the influence of nearest-neighbor (NN) repulsion on the low
frequency phase diagram of a quarter-filled Hubbard-Holstein chain. The NN
repulsion term induces the apparition of two new long range ordered phases (one
CDW for positive and one CDW for
negative ) that did not exist in the V=0 phase diagram. These results
are put into perspective with the newly observed charge ordered phases in
organic conductors and an interpretation of their origin in terms of
electron-molecular vibration coupling is suggested.Comment: 10 pages, 10 figure
LDL-cholesterol lowering effect of a generic product of simvastatin compared to simvastatin (Zocor™) in Thai hypercholesterolemic subjects – a randomized crossover study, the first report from Thailand
BACKGROUND: It is commonly agreed that people with a high blood LDL-cholesterol will have a higher risk of coronary artery disease (CAD) than people with low blood LDL-cholesterol. Due to the increasingly high costs of medication in Thailand, the government has set up several measures to combat the problem. One of such strategies is to promote the utilization of locally manufactured drug products, especially those contained in the National Drug List. Simvastatin, an HMG-CoA reductase inhibitor, is listed as an essential drug for the treatment of hypercholesterolemia. Here, we reported the study on the LDL-cholesterol-lowering effect of a generic simvastatin product in comparison with the Zocor(©), in 43 healthy thai volunteers. METHOD: The generic product tested was Eucor(©), locally manufactured by Greater Pharma Ltd., Part, Thailand, and the reference product was Zocor(©) (Merck Sharp & Dohme, USA). The two products were administered as 10-mg single oral doses in a two-period crossover design. After drug administration, serial blood samples were collected every 4 weeks for 16 weeks. The major parameter monitored in this study was blood LDL-cholesterol. RESULT: After taking the drugs for the first 8 weeks, no statistically significant difference was dedected in blood LDL-cholesterol between the first (Zocor(©)-treated) and the second (Eucor(©)-treated) groups. After crossover and taking drugs for further 8 weeks, a similar result was obtained, i.e., no significant difference in blood LDL-cholesterol between the first (Eucor(©)-treated) and the second (Zocor(©)-treated) groups was observed. Upon completion of the 16-week study, there was also no statisticaly significant difference in the changes of all tested blood parameters between the two products (randomized block ANOVA, N = 37). Only minor side effects, mainly dizziness and nausea, were observed in both products. CONCLUSION: Our study demonstrated no significant differences in the therapeutic effect and safety between the generic and original simvastatin products
Association of ICAM3 genetic variant with severe acute respiratory syndrome
Genetic polymorphisms have been demonstrated to be associated with vulnerability to human infection. ICAM3, an intercellular adhesion molecule important for T cell activation, and FCER2 (CD23), an immune response gene, both located on chromosome 19p13.3, were investigated for host genetic susceptibility and association with clinical outcome. A case-control study based on 817 patients with confirmed severe acute respiratory syndrome (SARS), 307 health care worker control subjects, 290 outpatient control subjects, and 309 household control subjects unaffected by SARS from Hong Kong was conducted to test for genetic association. No significant association to susceptibility to SARS infection caused by the novel coronavirus (SARS-CoV) was found for the FCER2 and the ICAM3 single nucleotide polymorphisms. However, patients with SARS homozygous for ICAM3 Gly143 showed significant association with higher lactate dehydrogenase levels (P = .0067; odds ratio [OR], 4.31 [95% confidence interval {CI}, 1.37-13.56]) and lower total white blood cell counts (P = .022; OR, 0.30 [95% CI, 0.10-0.89]) on admission. These findings support the role of ICAM3 in the immunopathogenesis of SARS. © 2007 by the Infectious Diseases Society of America. All rights reserved.published_or_final_versio
Perturbations of Noise: The origins of Isothermal Flows
We make a detailed analysis of both phenomenological and analytic background
for the "Brownian recoil principle" hypothesis (Phys. Rev. A 46, (1992), 4634).
A corresponding theory of the isothermal Brownian motion of particle ensembles
(Smoluchowski diffusion process approximation), gives account of the
environmental recoil effects due to locally induced tiny heat flows. By means
of local expectation values we elevate the individually negligible phenomena to
a non-negligible (accumulated) recoil effect on the ensemble average. The main
technical input is a consequent exploitation of the Hamilton-Jacobi equation as
a natural substitute for the local momentum conservation law. Together with the
continuity equation (alternatively, Fokker-Planck), it forms a closed system of
partial differential equations which uniquely determines an associated
Markovian diffusion process. The third Newton law in the mean is utilised to
generate diffusion-type processes which are either anomalous (enhanced), or
generically non-dispersive.Comment: Latex fil
Academic Performance and Behavioral Patterns
Identifying the factors that influence academic performance is an essential
part of educational research. Previous studies have documented the importance
of personality traits, class attendance, and social network structure. Because
most of these analyses were based on a single behavioral aspect and/or small
sample sizes, there is currently no quantification of the interplay of these
factors. Here, we study the academic performance among a cohort of 538
undergraduate students forming a single, densely connected social network. Our
work is based on data collected using smartphones, which the students used as
their primary phones for two years. The availability of multi-channel data from
a single population allows us to directly compare the explanatory power of
individual and social characteristics. We find that the most informative
indicators of performance are based on social ties and that network indicators
result in better model performance than individual characteristics (including
both personality and class attendance). We confirm earlier findings that class
attendance is the most important predictor among individual characteristics.
Finally, our results suggest the presence of strong homophily and/or peer
effects among university students
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