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5 result(s) for "Hagar, Elsherbini"
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Temporary Right-Ventricular Assist Devices: A Systematic Review
Acute right-sided heart failure (RHF) is a complex clinical syndrome, with a wide range of clinical presentations, associated with increased mortality and morbidity, but about which there is a scarcity of evidence-based literature. A temporary right-ventricular assist device (t-RVAD) is a potential treatment option for selected patients with severe right-ventricular dysfunction as a bridge-to-recovery or as a permanent solution. We sought to conduct a systematic review to determine the safety and efficacy of t-RVAD implantation. Thirty-one studies met the inclusion criteria, from which data were extracted. Successful t-RVAD weaning ranged between 23% and 100%. Moreover, 30-day survival post-temporary RAVD implantation ranged from 46% to 100%. Bleeding, acute kidney injury, stroke, and device malfunction were the most commonly reported complications. Notwithstanding this, t-RVAD is a lifesaving option for patients with severe RHF, but the evidence stems from small non-randomized heterogeneous studies utilizing a variety of devices. Both the etiology of RHF and time of intervention might play a major role in determining the t-RVAD outcome. Standardized endpoints definitions, design and methodology for t-RVAD trials is needed. Furthermore, efforts should continue in improving the technology as well as improving the timely provision of a t-RVAD.
Intermittent levosimendan infusion in ambulatory patients with end-stage heart failure: a systematic review and meta-analysis of 984 patients
We sought to synthesize the available evidence regarding safety and efficacy of intermittent levosimendan (LEVO) infusions in ambulatory patients with end-stage heart failure (HF). Safety and efficacy of ambulatory intermittent LEVO infusion in patients with end-stage HF are yet not established. We systematically searched MEDLINE, EMBASE, SCOPUS, Web of Science, and Cochrane databases, from inception to January 30, 2021 for studies reporting outcome of adult ambulatory patients with end-stage HF treated with intermittent LEVO infusion. Fifteen studies (8 randomized and 7 observational) comprised 984 patients (LEVO [N = 727] and controls [N = 257]) met the inclusion criteria. LEVO was associated with improved New York Heart Association (NYHA) functional class (weighted mean difference [WMD] −1.04, 95%CI: −1.70 to −0.38, p < 0.001, 5 studies, I2 = 93%), improved left ventricular (LV) ejection fraction (WMD 4.0%, 95%CI: 2.8% to 5.3%, p < 0.001, 6 studies, I2 = 9%), and reduced BNP levels (WMD −549 pg/mL, 95%CI −866 to −233, p < 0001, 3 studies, I2 = 66%). All-cause death was not different (RR 0.65, 95%CI: 0.38 to 1.093, p = 0.10, 6 studies, I2 = 0), but cardiovascular death was lower on LEVO (RR 0.34, 95%CI: 0.13 to 0.87, p = 0.02, 3 studies, I2 = 0) compared to controls. Furthermore, health-related quality of life (HRQoL) was improved alongside with reduced LV size following LEVO infusions. Major adverse events were not different between LEVO and placebo. In conclusion, intermittent LEVO infusions in ambulatory patients with end-stage HF is associated with less frequent cardiovascular death alongside with improved NYHA class, quality of life, BNP levels, and LV function. However, the current evidence is limited by heterogeneous and relatively small studies.
High-precision SAW bandpass filtering at 1747.5 MHz for LTE applications using wavelet transform techniques
Recent developments in mobile communication technologies have intensified the demand for higher data rates, necessitating the use of elevated carrier frequencies and compact, high-performance, cost-effective radio frequency (RF) filters. Surface acoustic wave (SAW) filters offer notable advantages in mobile phone applications due to their low insertion loss, compact footprint, and scalable manufacturing. These attributes make them particularly well-suited to meet the growing need for affordable filtering solutions at increasingly higher operating frequencies. This paper presents the design and simulation of a wavelet transform-based surface acoustic wave (SAW) bandpass filter centered at 1747.5 MHz, optimized for GSM/LTE applications. The filter employs a multi-stage configuration enhanced by window functions such as Gaussian, Kaiser, Hanning, and Hamming to achieve precise null bandwidth control and effective side-lobe suppression. Wavelet transform integration streamlines spectral decomposition, enabling efficient frequency-domain analysis and reducing computational complexity. Finite element modeling is performed using COMSOL Multiphysics to simulate the electromechanical behavior of piezoelectric substrates, specifically quartz types. MATLAB is utilized for wavelet-domain signal processing and graphical analysis. Simulation results reveal a passband width of approximately 17.736 MHz, side-lobe attenuation below 140 dB, and stable center frequency alignment across substrate variations. FFT plots confirm strong frequency selectivity, while displacement profiles illustrate substrate-dependent acoustic wave propagation and energy confinement. The proposed wavelet-integrated SAW filter demonstrates high spectral resolution, robust frequency stability, and low-loss transmission, validating its potential for next-generation RF front-end systems.
Wavelet Transform Processor Based Surface Acoustic Wave Devices
Due to their numerous advantages, Wavelet transform processor-based acoustic wave devices constitute an interesting approach for various engineering disciplines, such as signal analysis, speech synthesis, image recognition and atmospheric and ocean wave analysis. The major aim of this paper is to review the most recent methods for implementing wavelet transform processor-based surface acoustic wave devices. Accordingly, the goal of this paper is to compare different models, and it will provide a generalized model with small insertion loss values and side lobe attenuation, making it suitable for designing multiplexer filter banks and also to ease the way for the continued evolution of device design. In this paper, a generalized framework on surface acoustic wave devices is presented in terms of mathematical equations, types of materials, crystals types, and interdigital transducer design in addition to addressing some relevant problems.