•Enhances reconstruction of turbulentmean flows by assimilating disparate data•Proposes a regularized ensemble DA method to assimilate disparate data sources•Presents the equivalence of REnKF and ...EnKF for disparate data assimilation•Demonstrates merits of the proposed method for near-wall flow reconstruction
Reconstruction of turbulent flow based on data assimilation methods is of significant importance for improving the estimation of flow characteristics by incorporating limited observations. Existing works mainly focus on using only one observation data source, e.g., velocity, wall pressure, lift or drag force, to reconstruct the flow. In practical applications observations are disparate data sources that often vary in dimension and quality. Simultaneously incorporating these disparate data is worth investigation to improve the flow reconstruction. In this work, we investigate the disparate data assimilation with ensemble methods to enhance the reconstruction of turbulent mean flows. Specifically, a regularized ensemble Kalman method is employed to incorporate the observation of velocity and different sources of wall quantities (e.g., wall shear stress, wall pressure distribution, lift and drag force). Three numerical examples are used to demonstrate the capability of the proposed framework for assimilating disparate observation data. The first two cases, i.e., a one-dimensional planar channel flow and a two-dimensional transitional flow over plate, are used to incorporate both the sparse velocity and wall friction. In the third case of the flow over periodic hills, the wall pressure distribution and the lift and drag force are regarded as observation in addition to velocity, to recover the flow fields. The results demonstrate the merits of incorporating various disparate data sources to improve the accuracy of the flow-field estimation. The ensemble-based method can assimilate disparate data non-intrusively and robustly without requiring significant changes to the model simulation codes. The method demonstrated here opens up possibilities for assimilating realistic experimental data, which are often disparate.
The triglyceride-glucose (TyG) index could serve as a convenient substitute of insulin resistance (IR), but epidemiological evidence on its relationship with the long-term risk of mortality is ...limited.
Participants from the National Health and Nutrition Examination Survey during 1999-2014 were grouped according to TyG index (<8, 8-9, 9-10, >10). Cox regression was conducted to compute the hazard ratios (HRs) and 95% confidence interval (CI). Restricted cubic spline and piecewise linear regression were performed to detect the shape of the relationship between TyG index and mortality.
A total of 19,420 participants (48.9% men) were included. On average, participants were followed-up for 98.2 months, and 2,238 (11.5%) and 445 (2.3%) cases of mortality due to all-cause or cardiovascular disease were observed. After adjusting for confounders, TyG index was independently associated with an elevated risk of all-cause (HR, 1.10; 95% CI, 1.00-1.20) and cardiovascular death (HR, 1.29; 95% CI, 1.05-1.57). Spline analyses showed that the relationship of TyG index with mortality was non-linear (All non-linear
< 0.001), and the threshold value were 9.36 for all-cause and 9.52 for cardiovascular death, respectively. The HRs above the threshold point were 1.50 (95% CI, 1.29-1.75) and 2.35 (95% CI, 1.73-3.19) for all-cause and cardiovascular death. No significant difference was found below the threshold points (All
> 0.05).
Elevated TyG index reflected a more severe IR and was associated with mortality due to all-cause and cardiovascular disease in a non-linear manner.
Ventricular septal defect (VSD) is the most common congenital heart defect. Previous studies have reported genetic variations in the encoding region of CITED2 highly associated with cardiac ...malformation but the role of CITED2 gene promoter variations in VSD patients has not yet been explored. We investigated the variation of CITED2 gene promoter and its impacts on gene promoter activity in the DNA of paediatric VSD patients. A total of seven variations were identified by Sanger sequencing in the CITED2 gene promoter region in 400 subjects, including 200 isolated and sporadic VSD patients and 200 healthy controls. Using dual‐luciferase reporter assay, we found four of the 7 variations identified significantly decreased the transcriptional activity of the CITED2 gene promoter in HEK‐293 cells (P < .05). Further, a bioinformatic analysis with the JASPAR databases was performed and a cluster of putative binding sites for transcription factors was created or disrupted by these variations, leading to low expression of CITED2 protein and development of VSD. Our study for the first time demonstrates genetic variations in the CITED2 gene promoter in the Han Chinese population and the role of these variations in the development of VSD, providing new insights into the aetiology of CHD.
The benefits and adverse effects of corticosteroids in the treatment of severe community-acquired pneumonia (CAP) have not been well assessed. The aim of this systematic review of the literature and ...meta-analysis was to evaluate the clinical efficacy of adjuvant corticosteroid therapy in patients with severe CAP.
The following databases were searched: PubMed, the Cochrane database, Embase, Wanfang, the China National Knowledge Infrastructure (CNKI), and the WeiPu (VIP) database in Chinese. Published randomized controlled clinical trial results were identified that compared corticosteroid therapy with conventional therapy for patients with severe CAP, up to November 2016. The relative risk (RR), weighted mean difference (WMD), and 95% confidence interval (CI) were evaluated. Statistical analysis was performed using STATA 10.0. The quality of the published studies was evaluated using the Oxford quality scoring system (Jadad scale).
Ten randomized controlled trials (RCTs) were identified that included 729 patients with severe CAP. Data analysis showed that corticosteroid therapy did not have a statistically significant clinical effect in patients with severe CAP (RR: 1.19; 95% CI: 0.99–1.42), mechanical ventilation time (WMD: −2.30; 95% CI: −6.09–1.49). However, corticosteroids treatment was significantly associated with reduced in-hospital mortality (RR: 0.49; 95% CI: 0.29–0.85), reduced length of hospital stay (WMD: −4.21; 95% CI: −6.61 to −1.81).
Corticosteroids adjuvant therapy in patients with severe CAP may reduce the rate of in-hospital mortality, reduce the length of hospital stay, and reduce CRP levels.
In practical scenarios, digital predistortion (DPD) systems are typically deployed on hardware platforms. However, the current time delay alignment algorithm, a critical component of DPD processing, ...requires substantial hardware resource allocation. Consequently, this brief introduces a novel delay estimation algorithm aimed at simplifying the time alignment segment, including both integer and fractional elements. The integer alignment method is established on an adaptive filter framework, while the fractional component leverages a recursive least square (RLS) algorithm, based on a Farrow structure, to circumvent extensive matrix calculations. The complexity analysis, coupled with experimental results show that the proposed methods not only preserve high accuracy but also substantially diminish computational resource demands by 88.7% and 87.8%, respectively, when compared with two prevailing delay estimation techniques. This enhancement notably augments the performance of hardware-based DPD systems.
In this study, Large Eddy Simulation (LES) of supersonic turbulent mixing and combustion adopting a Partially Stirred Reactor (PaSR) sub-grid combustion model is performed for a hydrogen fueled model ...scramjet combustor. The compressible LES solver, which adopts a skeleton of 27 steps and 9 species hydrogen chemical kinetics model, is used to simulate the flowing and combustion processes based on structured hexahedral grids. The code is implemented in an Open Source Field Operation and Manipulation (OpenFOAM) solver, and validated against experimental data in terms of mean axial velocity and static temperature at different cross-sections, all show good predictions. An analysis of the flow field is carried out to investigate the supersonic turbulent flame structure and combustion mode in the combustor. Mixture fraction is extracted to indicate the reaction progress at different sites, which donates the most likely flame locations when at stoichiometric. Comparison of combustion parameters including OH mass fraction, scalar dissipation rate, flame index and heat release rate spatial distribution reveals that the supersonic combustion has the characteristics of a turbulent diffusion flame, where combustion is held at non-premixed mode controlled by turbulent mixing in the shear layers. A time scale analysis, the Damköhler Number is performed to examine these reactive zones in more detail. The role of auto-ignition in flame stabilization and lift-off is revealed.
•A skeleton of 27 steps with 9 species chemical kinetics for hydrogen is applied.•Stoichiometrical flame locations and different combustion modes are recognized.•The Damköhler number is extracted to indicate auto-ignition or flame extinction.•Species concentration and heat release rate is plotted in mixture fraction space.
N-doped porous carbons of C(N)-n were prepared for remarkable rate capacitive properties and excellent CO2 capture performance using Chitosan as both carbon and nitrogen sources. At the edge of ...amorphous C(N)-n materials, a part of atoms are arranged ordered on account of the graphitization. Besides, the optimal ID/IG ratio is 1.02. In the optimized sample of C(N)-700, N element exists in the framework as pyridinic N, pyrrodic N, quaternary N, oxidized N and the proportion is 7.3%. Moreover, the specific surface area and pore volume reach 243 m2/g and 0.633 cm3/g, respectively. In 6 M KOH, the C(N)-700 material generates a pseudocapacitance along with the double-layer capacitance (EDLC). When the current density is 0.2 A/g, the discharge capacity and energy density are 502 F/g and 6.5 Wh/kg, respectively. Compared with the discharge capacity at 0.2 A/g, it still keeps 61.7% at 40 A/g. The superior electrochemical performance has a closely connection with the huge pore volume, surface area and the doping of N species, which afford rapid ions migration, abundant residence sites and outstanding pseudocapacitance properties. CO2 capture behavior on the N-doped carbons complie with Bangham mode. When the system temperature is 25 °C, the C(N)-700 material achieves an appreciable capture amount of 4.25 mmol/g in a stream of 40 mL/min. At room temperature, the adsorption capacity ratios of CO2/N2 and CO2/O2 are 2.6 and 3.7, respectively. The superior CO2 adsorption performance is also closely in connection with the unique pore structure and plentiful N affinity places.
•Porous N-doped carbon materials of C(N)-n were synthesized through chemical bonds between N heteroatoms and carbon skeleton.•The optimal N-doped C(N)-700 is a porous material with a large pore volume of 0.633 cm3/g and a high N content of 7.3%.•At 40 A/g, the discharge capacity is 61.7% of that at 0.2 A/g. At 25 °C, a great CO2 uptake of 4.25 mmol/g is achieved.
Objectives
Lysine 2‐hydroxyisobutyrylation (Khib) is a novel acylation that regulates glycolysis. Little has been done in human diseases regarding the role of Khib. The present study was designed to ...reveal the role of Khib in the development of atrial fibrillation (AF) associated with heart valve disease.
Methods
Discarded right atrial appendage tissues during the cannulation procedure were collected from AF and sinus rhythm (SR) patients with rheumatic heart valve disease. The protein profiles and Khib sites were identified and qualified by Tandem Mass Tag labeling and liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) technology. Bioinformatic tools, including Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and protein‐protein interaction, were also used to explore the biological function between AF and SR.
Results
A total of 6,523 matched spectrum, 3,234 peptides, 2,867 modified peptides, corresponding to 579 proteins and 2,900 sites from LC‐MS/MS analysis were identified. Of these identified proteins and sites, 480 proteins and 2,275 sites were quantifiable. The length of most peptides distributed between 7 and 22, which was consistent with the length of tryptic peptides. Differentially expressed Khib sites analysis showed that there were 35 and 48 Khib sites related to 124 and 67 proteins exhibited upregulation and downregulation in AF compared to SR. Subcellular location analysis of Khib ‐related proteins revealed that cytoplasm, nucleus, and extracellular accounted for the most proportion. Bioinformatic analysis demonstrated that proteins with Khib were significantly enriched in different biological approach, such as cysteine and methionine metabolism, cGMP‐PKG signaling pathway, and glucose‐responsive energy metabolism.
Conclusions
The present study for the first time revealed larger number of differentially expressed Khib sites between AF and SR in patients with rheumatic valve disease. The proteins related to these sites are involved in diverse cellular processes including energy metabolism. These results indicate that Khib modification might be a key factor in occurrence of AF in patients with rheumatic heart valve disease.
Inflammation plays a vital role in the occurrence and progression of atrial fibrillation (AF). The association between pericoronary adipose tissue attenuation (PCATA) and AF recurrence following ...ablation has not been fully clarified.
We aimed to evaluate the association between PCATA and AF recurrence after radiofrequency catheter ablation (RFCA).
Patients who underwent the first RFCA for AF and performed coronary computed tomography angiography before ablation between 2018 and 2021 were enrolled. The predictive values of PCATA for AF recurrence after ablation were investigated. The area under curve (AUC), relative integrated discrimination improvement (IDI), and categorical free net reclassification improvement (NRI) were used to assess the discrimination ability of different models for AF recurrence.
During 1-year follow-up, 34.1% patients experienced AF recurrence. The multivariable analysis model revealed that PCATA of the right coronary artery (RCA) was an independent risk factor for AF recurrence. Patients with a high level of RCA-PCATA had a high risk of recurrence, after adjusting for other risk factors by restricted cubic splines. The performance in predicting AF recurrence was significantly improved by adding the marker of RCA-PCATA to the clinical model (AUC: 0.724 vs. 0.686, p = .024), with a relative IDI of 0.043 (p = .006) and continuous NRI of 0.521 (p < .001).
PCATA of RCA was independently associated with AF recurrence after ablation. PCATA may be helpful for risk classification for AF ablation patients.
This paper numerically investigated the dynamic characteristics of combustion in a model scramjet. Three-dimensional compressible large eddy simulation was performed on a hydrogen fueled combustor ...and pressure fluctuations were recorded. The analysis of pressure data showed that the combustion processes are intrinsically unstable under supersonic air inflow conditions. Flame dynamics were convinced by the fluctuations in flame lift-off distance away from the strut base. Combined with the corresponding time interval, instantaneous flame speed was calculated. Results indicated that pressure oscillations at different locations show difference in amplitude, frequency, and the underlying control mechanism. Flame front oscillation analysis showed that the flame–shock interaction in the strut recirculation zone was responsible for the combustion instability. Flame dynamics were compared with low-speed turbulent lifted flames. The transition between flame propagation just after the strut and shock-induced combustion in the subsonic bubble at the intersection of two wall-reflected oblique shocks made for the flame stabilization.
•The reasons for pressure oscillation at different locations are distinguished.•Flame lift-off distance and the instantaneous flame speed are quantified.•Intermittent formation of subsonic bubble controls the combustion oscillation.•Flame propagation and shock-induced combustion jointly stabilize the flame.
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