30 research outputs found
On the Performance of Cognitive Underlay SIMO Networks over Equally Correlated Rayleigh Fading Channels
The performance of single-input multiple-output (SIMO) cognitive spectrum sharing networks with the presence of equally correlated Rayleigh fading channels is investigated. In particular, based on the truncated infinitive series of cumulative distribution function (CDF) and probability density function (PDF) of the end-to-end signal-to-noise ratios (SNRs), close-form expressions are provided for the system outage performance, bit error rate and ergodic capacity. It is shown that the system performance merely depends on the correlation coefficient between antennas. Monte-Carlo simulations are also contributed to confirm the accuracy of our analysis
Performance analysis of multihop full-duplex NOMA systems with imperfect interference cancellation and near-field path-loss
Outage probability (OP) and potential throughput (PT) of multihop full-duplex (FD)
nonorthogonal multiple access (NOMA) systems are addressed in the present paper. More precisely,
two metrics are derived in the closed-form expressions under the impact of both imperfect successive
interference cancellation (SIC) and imperfect self-interference cancellation. Moreover, to model short
transmission distance from the transmit and receive antennae at relays, the near-field path-loss is
taken into consideration. Additionally, the impact of the total transmit power on the performance
of these metrics is rigorously derived. Furthermore, the mathematical framework of the baseline
systems is provided too. Computer-based simulations via the Monte Carlo method are given to
verify the accuracy of the proposed framework, confirm our findings, and highlight the benefits of
the proposed systems compared with the baseline one.Web of Science231art. no. 52
Kinetics of cardiovascular and inflammatory biomarkers in paediatric dengue shock syndrome
Glycocalyx disruption and hyperinflammatory responses are implicated in the pathogenesis of dengue-associated vascular leak, however little is known about their association with clinical outcomes of patients with dengue shock syndrome (DSS). We investigated the association of vascular and inflammatory biomarkers with clinical outcomes and their correlations with clinical markers of vascular leakage. We performed a prospective cohort study in Viet Nam. Children ≥5 years of age with a clinical diagnosis of DSS were enrolled into this study. Blood samples were taken daily during ICU stay and 7–10 days after hospital discharge for measurements of plasma levels of Syndecan-1, Hyaluronan, Suppression of tumourigenicity 2 (ST-2), Ferritin, N-terminal pro Brain Natriuretic Peptide (NT-proBNP), and Atrial Natriuretic Peptide (ANP). The primary outcome was recurrent shock. Ninety DSS patients were enrolled. Recurrent shock occurred in 16 patients. All biomarkers, except NT-proBNP, were elevated at presentation with shock. There were no differences between compensated and decompensated DSS patients. Glycocalyx markers were positively correlated with inflammatory biomarkers, haematocrit, percentage haemoconcentration, and negatively correlated with stroke volume index. While Syndecan-1, Hyaluronan, Ferritin, and ST-2 improved with time, ANP continued to be raised at follow-up. Enrolment Syndecan-1 levels were observed to be associated with developing recurrent shock although the association did not reach the statistical significance at the P < 0.01 (OR = 1.82, 95% CI 1.07–3.35, P = 0.038). Cardiovascular and inflammatory biomarkers are elevated in DSS, correlate with clinical vascular leakage parameters and follow different kinetics over time. Syndecan-1 may have potential utility in risk stratifying DSS patients in ICU
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Assessing the efficacy and safety of magnesium sulfate for management of autonomic nervous system dysregulation in Vietnamese children with severe hand foot and mouth disease.
BACKGROUND: Brainstem encephalitis is a serious complication of hand foot and mouth disease (HFMD) in children. Autonomic nervous system (ANS) dysregulation and hypertension may occur, sometimes progressing to cardiopulmonary failure and death. Vietnamese national guidelines recommend use of milrinone if ANS dysregulation with Stage 2 hypertension develops. We wished to investigate whether magnesium sulfate (MgSO4) improved outcomes in children with HFMD if used earlier in the evolution of the ANS dysregulation (Stage 1 hypertension). METHODS: During a regional epidemic we conducted a randomized, double-blind, placebo-controlled trial of MgSO4 in children with HFMD, ANS dysregulation and Stage 1 hypertension, at the Hospital for Tropical Diseases in Ho Chi Minh city. Study participants received an infusion of MgSO4 or matched placebo for 72 h. We also reviewed data from non-trial HFMD patients in whom milrinone failed to control hypertension, some of whom received MgSO4 as second line therapy. The primary outcome for both analyses was a composite of disease progression within 72 h - addition of milrinone (trial participants only), need for ventilation, shock, or death. RESULTS: Between June 2014 and September 2016, 14 and 12 participants received MgSO4 or placebo respectively, before the trial was stopped due to futility. Among 45 non-trial cases with poorly controlled hypertension despite high-dose milrinone, 33 received MgSO4 while 12 did not. There were no statistically significant differences in the composite outcome between the MgSO4 and the placebo/control groups in either study (adjusted relative risk (95%CI) of [6/14 (43%) vs. 6/12 (50%)], 0.84 (0.37, 1.92), p = 0.682 in the trial and [1/33 (3%) vs. 2/12 (17%)], 0.16 (0.01, 1.79), p = 0.132 in the observational cohort). The incidence of adverse events was similar between the groups. Potentially toxic magnesium levels occurred very rarely with the infusion regime used. CONCLUSION: Although we could not demonstrate efficacy in these studies, there were no safety signals associated with use of 30-50 mg/kg/hr. MgSO4 in severe HFMD. Intermittent outbreaks of HFMD are likely to continue across the region, and an adequately powered trial is still needed to evaluate use of MgSO4 in controlling hypertension in severe HFMD, potentially involving a higher dose regimen. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01940250 (Registered 22 AUG 2013). Trial sponsor: University of Oxford
Performance Evaluation of Incremental Relaying in Underlay Cognitive Radio Networks with Imperfect CSI
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The Surgical Outcomes of Diaphyseal Fractures of Radius and Ulna treated by Plate and Screws Fixation in Vietnam
Objectives: 1) Study the clinical and radiographic characteristics of both bones forearm fractures in adults. 2) Evaluate the surgical outcomes of plate and screws fixation for these fractures.Material and methods: This retrospective study included 66 cases of both bones forearm fractures who were treated by open reduction and internal fixation (ORIF) with plate and screws at Viet Duc Hospital and Hanoi Medical University Hospital between January 2010 and June 2013.Results: The average age of the patients was 34.73 ± 13.54; the ratio of men to women was 2.5/1;Traffic accident was the major mechanism of injury; fractures of middle third of radius and ulna were the most common, accounting for 48.49% of cases. Fractures in left-side were more than right. The surgical outcomes were excellent in 75.8% of cases, satisfactory in 18.2% and unsatisfactory in 6%. There were no failures.Conclusion: Plate and screws fixation of both bones forearm fractures had good results.</p