21 research outputs found

    AI-based investigation and mitigation of rain effect on channel performance with aid of a novel 3D slot array antenna design for high throughput satellite system

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    Rain attenuation poses a significant challenge for high-throughput communication systems. In response, this paper introduces an artificial intelligence (AI) model designed for predicting and mitigating rain-induced impairments in high-throughput satellite (HTS) to land channels. The model is based on three AI algorithms developed using 3D antenna design to characterize, analyze, and mitigate rain induced attenuation, optimizing channel quality specifically in the United Arab Emirates (UAE). The study evaluates various parameters, including rain-specific attenuation, effective slant path through rain, rain induced attenuation, signal carrier-to-noise ratio, and symbol error rate, for five conventional modulation schemes: Quadrature Phase-Shift Keying (QPSK), 8-Phase Shift Keying (8-PSK), 16-Quadrature Amplitude Modulation (16-QAM), 32-QAM, and 64-QAM. Additionally, the paper introduces a new database detailing rain-induced attenuation in HTS channels in the UAE at different frequencies using measured rainfall intensities. The paper concludes by proposing a smart antenna design with a frequency diversity technique for fade mitigation. Results indicate that rain-induced attenuation varies significantly based on rainfall rate and frequency. Specifically, at 25 GHz and a rainfall rate of 100 mm/h, the rain-induced attenuation can reach as high as 15 dB, resulting in a significant decline in signal quality and link performance. The proposed AI model demonstrates the ability to intelligently predict rain-induced attenuation and channel quality for various rainfall rates and frequencies. This information can be valuable for optimizing satellite link design and operation, ultimately enhancing the reliability and quality of satellite communications. The proposed two-slot smart antenna design utilizes frequency diversity to effectively mitigate rain attenuation, contributing to the overall improvement of link reliability and quality

    The Tpeak – Tend interval as an electrocardiographic risk marker of arrhythmic and mortality outcomes: a systematic review and meta-analysis

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    Background: The Tpeak – Tend interval, an electrocardiographic marker reflecting transmural dispersion of repolarization, has been used to predict ventricular tachycardia/fibrillation (VT/VF) and sudden cardiac death (SCD) in different clinical settings. Objective: This systematic review and meta-analysis evaluated the significance of Tpeak – Tend interval in predicting arrhythmic and/or mortality endpoints. Methods: PubMed, Embase, Cochrane Library and CINAHL Plus databases were searched through 30th November 2016.Results: Of the 854 studies identified initially, 33 observational studies involving 155856 patients were included in our meta-analysis. Tpeak – Tend interval prolongation (mean cut-off: 103.3 ± 17.4 ms) was a significant predictor of the arrhythmic or mortality outcomes (odds ratio (OR): 1.14, 95% CI: 1.11 to 1.17, p < 0.001). When different end-points were analyzed, the ORs are as follows: VT/VF (1.10, 95% CI: 1.06 to 1.13, p < 0.0001), SCD (1.27, 95% CI 1.17 to 1.39, p < 0.0001), cardiovascular death (1.40, 95% CI 1.19 to 1.64, p < 0.0001), and all-cause mortality (4.56, 95% CI 0.62 to 33.68, p < 0.0001). Subgroup analysis for each disease revealed that the risk of VT/VF or death was highest for Brugada syndrome (OR: 5.68, 95% CI: 1.57 to 20.53, p < 0.01), followed by hypertension (OR: 1.52, 95% CI: 1.26 to 1.85, p < .0001), heart failure (OR: 1.07, 95% CI: 1.04 to 1.11, p < .0001) and ischemic heart disease (OR: 1.06, 95% CI: 1.02 to 1.10, p = 0.001). In the general population, a prolonged Tpeak – Tend interval also predicted arrhythmic or mortality outcomes (OR: 1.59, 95% CI: 1.21 to 2.09, p < 0.001).Conclusion: The Tpeak – Tend interval is useful risk stratification tool in different diseases and in the general population

    Channel measurements, characterization, and modeling for land mobile satellite terminals in tropical regions at Ku-band

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    Severe tropical weather dynamics impairments on the earth-sky signal quality at the Ku-band relative to temperate weather increase the demand for land mobile satellite (LMS) channel characterization and modeling specific to tropical regions. Variation in weather dynamics decreases the accuracy of the existing LMS channel models if applied to the tropics. This paper presents a tropical weather-aware LMS channel model that can be applied at areas with diverse atmospheric (rain, clouds, and tropospheric scintillation) and mobility impairments. The proposed tropical-LMS channel (TRO-LMSC) model is designed based on actual experimental measurements conducted in a tropical area. The TRO-LMSC model involves multipath design, mobility model, rain impairment model, cloud impairment model, tropospheric scintillation model, and link budget module (LBM). The proposed model shows improved channel modeling accuracy and comprehensiveness with relatively less root mean square error (rmse), compared with existing models. Consequently, this improvement enhances the identification of the type and performance of the fade mitigation technique, the management of available communication resources, and the reliability and efficiency of the communication services

    On-the-move measurement analysis for Ka-band high throughput satellite and LiFi communication networks in tropical region

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    With the point in evaluating the performance of the On-the-Move (OTM) Satellite Communication and Light Fidelity (SatCom-LiFi), an extensive study of measurement has been conducted to give a wide vision of the SatCom-LiFi potential under a tropical region. As the interest for OTM network connectivity to offload the C-band capacity arises due to frequency spectrum scarcity, satellite networks offer to balance topographical requirements under tropical environment as the Next Generation Networks (NGN) trend for OTM communication system solutions. To date, mobile satellite terminal propagation model was carried out at temperate regions where further experimental measurement is needed under the OTM scenario in tropical region. This paper discusses on the areas where there are limited real-time data under the OTM scenario (e.g. rain attenuation, power arch) at Ka-band frequency. Integration infers, to be specific, the use of new elements capable in providing performance analysis of all systems involved and to take possible decision, in determining the need for a technically feasible solution. Measurement results reveal that, throughput data rate of 15 Mbps were able to be delivered for more than 80% of the time under the speed of 150 km/h with shielded mesh antenna. In addition to that, this paper reveals the favorable circumstances and inadequacies of OTM network quality, in which the measurement presented plays an important role for future researchers in distinguishing highly accurate predictions

    LHFPL5 mutation: A rare cause of non-syndromic autosomal recessive hearing loss

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    Hearing loss is a debilitating disorder that impairs language acquisition, resulting in disability in children and potential isolation in adulthood. Its onset can have a genetic basis, though environmental factors, which are often preventable, can also cause the condition. The genetic forms are highly heterogeneous, and early detection is necessary to arrange appropriate patient support. Here we report the molecular basis of hereditary hearing loss in a consanguineous family with multiple affected members from Oman. Combining homozygosity mapping with whole exome sequencing identified a novel homozygous nucleotide substitution c.575T > C in the lipoma HMGIC fusion partner-like 5 gene (LHFPL5), that converted the 192nd amino acid residue in the protein from a leucine to a proline, p.(Leu192Pro). Sanger sequencing confirmed segregation with the disease phenotype as expected for a recessive condition and the variant was absent in 123,490 subjects from various disease-specific and population genetic studies as well as 150 unrelated individuals and 35 deaf patients of Omani ethnicity. This study, which describes a novel LHFPL5 mutation in a family of Omani origin with hereditary hearing loss, supports previous clinical descriptions of the condition and contributes to the genetic spectrum of mutations in this form of deafness

    AI-Based Investigation and Mitigation of Rain Effect on Channel Performance With Aid of a Novel 3D Slot Array Antenna Design for High Throughput Satellite System

    No full text
    Rain attenuation poses a significant challenge for high-throughput communication systems. In response, this paper introduces an artificial intelligence (AI) model designed for predicting and mitigating rain-induced impairments in high-throughput satellite (HTS) to land channels. The model is based on three AI algorithms developed using 3D antenna design to characterize, analyze, and mitigate rain-induced attenuation, optimizing channel quality specifically in the United Arab Emirates (UAE). The study evaluates various parameters, including rain-specific attenuation, effective slant path through rain, rain-induced attenuation, signal carrier-to-noise ratio, and symbol error rate, for five conventional modulation schemes: Quadrature Phase-Shift Keying (QPSK), 8-Phase Shift Keying (8-PSK), 16-Quadrature Amplitude Modulation (16-QAM), 32-QAM, and 64-QAM. Additionally, the paper introduces a new database detailing rain-induced attenuation in HTS channels in the UAE at different frequencies using measured rainfall intensities. The paper concludes by proposing a smart antenna design with a frequency diversity technique for fade mitigation. Results indicate that rain-induced attenuation varies significantly based on rainfall rate and frequency. Specifically, at 25 GHz and a rainfall rate of 100 mm/h, the rain-induced attenuation can reach as high as 15 dB, resulting in a significant decline in signal quality and link performance. The proposed AI model demonstrates the ability to intelligently predict rain-induced attenuation and channel quality for various rainfall rates and frequencies. This information can be valuable for optimizing satellite link design and operation, ultimately enhancing the reliability and quality of satellite communications. The proposed two-slot smart antenna design utilizes frequency diversity to effectively mitigate rain attenuation, contributing to the overall improvement of link reliability and quality

    Predictive Role of Coagulation, Fibrinolytic, and Endothelial Markers in Patients with Atrial Fibrillation, Stroke, and Thromboembolism: A Meta-Analysis, Meta-Regression, and Systematic Review

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    Background: The pathophysiological mechanism associated with the higher prothrombotic tendency in atrial fibrillation (AF) is complex and multifactorial. However, the role of prothrombotic markers in AF remains inconclusive. Material/Methods: We conducted a meta-analysis of observational studies evaluating the association of coagulation activation, fibrinolytic, and endothelial function with occurrence of AF and clinical adverse events. A comprehensive subgroup analysis and meta-regression was performed to explore potential sources of heterogeneity. Results: A literature search of major databases retrieved 1703 studies. After screening, a total of 71 studies were identified. Pooled analysis showed the association of coagulation markers (D-dimer (weighted mean difference (WMD)=197.67 and p<0.001), fibrinogen (WMD=0.43 and p<0.001), prothrombin fragment 1-2 (WMD=0.53 and p<0.001), antithrombin III (WMD=23.90 and p=0.004), thrombin-antithrombin (WMD=5.47 and p=0.004)); fibrinolytic markers (tissue-type plasminogen activator (t-PA) (WMD=2.13 and p<0.001), plasminogen activator inhibitor (WMD=11.44 and p<0.001), fibrinopeptide-A (WMD=4.13 and p=0.01)); and endothelial markers (von Willebrand factor (WMD=27.01 and p<0.001) and soluble thrombomodulin (WMD=3.92 and p<0.001)) with AF. Conclusions: The levels of coagulation, fibrinolytic, and endothelial markers have been reported to be significantly higher in AF patients than in SR patients

    Statins in adult patients with HIV

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    Background: Patients with HIV have been found to suffer from lipid abnormalities, including elevated levels of total and LDLcholesterol as well as triglyceride levels. Abnormal lipid levels are associated with an increased risk of developing cardiovascular diseases, which are significant causes of mortality among the general population. Therefore, the objective of the current study is to conduct a systematic review with network meta-analysis to compare the effects of statins classes on HIV patients. Methods: Randomized clinical trials (RCTs) and observational studies published in English up to 31 December 2017, and which include direct and/or indirect evidence, will be included. Studies will be retrieved by searching four electronic databases and crossreferencing. Dual selection and abstraction of data will occur. The primary outcome will all-cause mortality, new event of acute myocardial infarction, stroke (hemorrhagic and ischemic), hospitalization for acute coronary syndrome and urgent revascularization procedures and cardiovascular mortality. Secondary outcomes will be assessment of the differences in change of total cholesterol (TC), low-density lipoprotein (LDL-C), apolipoprotein B (ApoB), high density lipoprotein (HDL-C). Risk of bias will be assessed using the Cochrane Risk of Bias assessment instrument for RCTs and the Strengthening the Reporting of Observational Studies in Epidemiology instrument for observational studies. Network meta-analysis will be performed using multivariate random-effects meta-regression models. The surface under the cumulative ranking curve will be used to provide a hierarchy of statins that reduce cardiovascular mortality in HIV patients. A revised version of the Cochrane Risk of Bias tool (RoB 2.0) will be used to assess the risk of bias in eligible RCTs. Results will be synthesized and analyzed using network meta-analysis (NMA). Overall strength of the evidence and publication bias will be evaluated. Subgroup and sensitivity analysis will also be performed. ResultsandConclusion: Ethics approval was not required for this study because it was based on published studies. The results and findings of this study will be submitted and published in a scientific peer-reviewed journal. The evidence will determine which combination of interventions are most promising for current practice and further investigation. Trial registration number: PROSPERO (CRD42017072996). Abbreviations: AMI = acute myocardial infarction, ART = antiretroviral therapy, CIs = confidence intervals, CV cardiovascular, HDL = high-density lipoprotein, HIV = human immunodeficiency virus, LDL = low-density lipoprotein, MD = mean difference, RCT = randomized clinical trials, RR = risk ratio, WC = waist circumference

    Platelets Cellular and Functional Characteristics in Patients with Atrial Fibrillation: A Comprehensive Meta-Analysis and Systematic Review

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    Background: This systematic review with meta-analysis aimed to determine the strength of evidence for evaluating the association of platelet cellular and functional characteristics including platelet count (PC), MPV, platelet distribution width (PDW), platelet factor 4, beta thromboglobulin (BTG), and p-selectin with the occurrence of atrial fibrillation (AF) and consequent stroke. Material/Methods: We conducted a meta-analysis of observational studies evaluating platelet characteristics in patients with paroxysmal, persistent and permanent atrial fibrillations. A comprehensive subgroup analysis was performed to explore potential sources of heterogeneity. Results: Literature search of all major databases retrieved 1,676 studies. After screening, a total of 73 studies were identified. Pooled analysis showed significant differences in PC (weighted mean difference (WMD)=-26.93 and p<0.001), MPV (WMD=0.61 and p<0.001), PDW (WMD=-0.22 and p=0.002), BTG (WMD=24.69 and p<0.001), PF4 (WMD=4.59 and p<0.001), and p-selectin (WMD=4.90 and p<0.001). Conclusions: Platelets play a critical and precipitating role in the occurrence of AF. Whereas distribution width of platelets as well as factors of platelet activity was significantly greater in AF patients compared to SR patients, platelet count was significantly lower in AF patients
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