Search results for "frequency [modulation]"
showing 10 items of 569 documents
Minimally invasive techniques in the treatment of saphenous varicose veins.
2008
Lower extremity venous insufficiency is common and increases with age. In addition to classical symptoms, it may result in skin changes and venous ulcers. Chronic venous insufficiency has a great impact on patients' health-related quality of life and is associated with considerable health care costs. Surgical ligation Of the junction with or without stripping has been the standard of care in the treatment of insufficient great and small saphenous veins. However, the recurrence rates are relatively high and surgery may be associated with serious adverse events and considerable down time; it is also cosmetically Suboptimal. To improve efficacy, patients' health-related quality of life and tre…
Does the origin of ablated premature ventricular contractions determine the level of left ventricular function improvement?
2020
Background: Premature ventricular contractions (PVCs) are associated with tachycardiomyopathy and high mortality rate. The treatment depends on the engaged ventricle. For PVCs originating from the right outflow tract (OT), radiofrequency catheter ablation (RFCA) is recommended (class IB‑R recommendation) in preference to pharmacotherapy. In those originating from the left ventricle, ablation is a class IIa B‑NR recommendation. Aims: The aim of the study was to assess the success of RFCA of PVCs based on arrhythmia origin. Methods: A total of 110 consecutive patients with monomorphic PVCs referred for ablation were enrolled and divided according to the site of ablation to the OT group and th…
Ultrasound-induced blood clot dissolution without a thrombolytic drug is more effective with lower frequencies.
2004
<i>Background and Purpose:</i> Therapeutic ultrasound as stand-alone therapy or in combination with rt-PA has proven to be an effective measure for recanalisation of acute vessel occlusion in different in vitro and in vivo studies. Uncertainty still exists concerning the optimal frequency and intensity with regard to the thrombolytic efficacy of ultrasound. The purpose of this study was a direct comparison of different ultrasound frequencies, when otherwise using identical measurement settings and parameters. <i>Methods:</i> Ultrasound-induced dissolution of fresh human blood clots was studied in a flow system using low-frequency continuous wave ultrasound of 20, 40 …
Enhancing the performance of HSDPA communication with multipoint transmission techniques
2015
The evolution of mobile phones, tablets and other mobile communication devices has led to a significant increase in the amount of data delivered over mobile networks. In order to satisfy the climbing data rate demands of customers, existing mobile broadband networks are being expanded with new features that allow ubiquitous and consistent networking experience. This research presents three multipoint transmission techniques for Wideband Code Division Multiple Access (WCDMA) based High-Speed Downlink Packet Access (HSDPA) communication protocol. Multiflow, High-Speed Single-Frequency Network (HS-SFN) and Multipoint-to-Point Single-Frequency Network (M2P-SFN) enable transmission of user-dedicat…
Electrocatheter-mediated High-voltage Pulsed Radiofrequency of the Dorsal Root Ganglion in the Treatment of Chronic Lumbosacral Neuropathic Pain
2019
Objectives: Despite the interest in scientific community, there is still poor evidence about pulsed radiofrequency (PRF) efficacy in the treatment of neuropathic pain. In order to determine whether high-voltage PRF and epidural adhesiolysis (PRF-EA) showed better results than epidural adhesiolysis alone (EA), a randomized, double-blind, comparative-effectiveness study was conducted in patients with chronic lumbosacral radiating pain and neuropathic features. Materials and Methods: A total of 41 patients were randomly allocated to 2 groups. Twenty-one patients were randomized to receive 2 cycles of 240 seconds high-voltage PRF followed by the injection of local anesthetics, hyaluronidase, an…
Noise effect in a sine-Gordon Lattice
2013
International audience; This paper is devoted to the influence of internal noise in a sine-Gordon chain exhibiting the well known nonlinear supratransmission phenomenon. It is shown that spatiotemporal noise can trigger breather modes with a given probability in a range of parameters where they do not occur without noise. A frequency analysis is carried out to quantify the degree of coherence of the emitted breather. It is shown that there exists an appropriate amount of noise which ensures the existence of breather modes with the best coherence.
Modification of a commercial atomic force microscopy for low-noise, high-resolution frequency-modulation imaging in liquid environment.
2011
A key issue for high-resolution frequency-modulation atomic force microscopy imaging in liquids is minimizing the frequency noise, which requires a detailed analysis of the corresponding noise contributions. In this paper, we present a detailed description for modifying a commercial atomic force microscope (Bruker MultiMode V with Nanoscope V controller), aiming at atomic-resolution frequency-modulation imaging in ambient and in liquid environment. Care was taken to maintain the AFMs original stability and ease of operation. The new system builds upon an optimized light source, a new photodiode and an entirely new amplifier. Moreover, we introduce a home-built liquid cell and sample holder …
Wiener-Granger Causality in Network Physiology with Applications to Cardiovascular Control and Neuroscience
2016
Since the operative definition given by C. W. J. Granger of an idea expressed by N. Wiener, the Wiener–Granger causality (WGC) has been one of the most relevant concepts exploited by modern time series analysis. Indeed, in networks formed by multiple components, working according to the notion of segregation and interacting with each other according to the principle of integration, inferring causality has opened a window on the effective connectivity of the network and has linked experimental evidences to functions and mechanisms. This tutorial reviews predictability improvement, information-based and frequency domain methods for inferring WGC among physiological processes from multivariate…
Even harmonic pulse train generation by cross-polarization-modulation seeded instability in optical fibers
2012
International audience; We show that, by properly adjusting the relative state of polarization of the pump and of a weak modulation, with a frequency such that at least one of its even harmonics falls within the band of modulation instability, one obtains a fully modulated wave at the second or higher even harmonic of the initial modulation. An application of this principle to the generation of a 80-GHz optical pulse train with high extinction ratio from a 40-GHz weakly modulated pump is experimentally demonstrated using a nonzero dispersion shifted fiber in the telecom C band.
The Palliative Care in the Metastatic Spinal Tumors. A Systematic Review on the Radiotherapy and Surgical Perspective
2022
Spine represents the most common site for metastatic disease involvement. Due to the close relationship between the spinal cord and critical structures, therapeutic management of spinal metastases remains challenging. Spinal localization can lead to neurological sequelae, which can significantly affect the quality of life in patients with a limited life expectancy. The authors conducted a systematic literature review according to PRISMA guidelines in order to determine the impact of the most updated palliative care on spinal metastases. The initial literature search retrieved 2526 articles, manually screened based on detailed exclusion criteria. Finally, 65 studies met the inclusion criteri…