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Long-term training leads experts to develop a focused and efficient organization of task-related neural networks. \"Neural efficiency\" hypothesis posits that neural activity is reduced in experts. Here we tested the following working hypotheses: compared to non-athletes, athletes showed lower cortical activation in task-sensitive brain areas during the processing of sports related and sports unrelated visuo-spatial tasks. To address this issue, cortical activation was examined with fMRI in 14 table tennis athletes and 14 non-athletes while performing the visuo-spatial tasks. Behavioral results showed that athletes reacted faster than non-athletes during both types of the tasks, and no accuracy difference was found between athletes and non-athletes. fMRI data showed that, athletes exhibited less brain activation than non-athletes in the bilateral middle frontal gyrus, right middle orbitofrontal area, right supplementary motor area, right paracentral lobule, right precuneus, left supramarginal gyrus, right angular gyrus, left inferior temporal gyrus, left middle temporal gyrus, bilateral lingual gyrus and left cerebellum crus. No region was significantly more activated in the athletes than in the non-athletes. These findings possibly suggest that long-standing training prompt athletes develop a focused and efficient organization of task-related neural networks, as a possible index of \"neural efficiency\" in athletes engaged in visuo-spatial tasks, and this functional reorganization is possibly task-specific.

The combustion characteristics of micro-combustors significantly impact the performance of micro-thermophotovoltaic (MTPV) systems. This study aims to investigate the effects of sinusoidal-shaped walls and catalyst segmentation on flame stability and combustion performance in a micro-combustor by using numerical methods. The numerical simulation with detailed gas-phase and surface reaction mechanisms is reliable, as the results of numerical simulation align with experimental data. The results show that the interplay between flame stability and sinusoidal-shaped walls is crucial, particularly because of the cavities formed by the sinusoidal-shaped walls of the micro-combustor. The gas-phase ignition position of the sinusoidal-shaped wall combustor moves upstream by 0.050 m compared to the planar-wall combustor, but the flame is stretched. The catalyst segments coated on the crest can shorten the flame length and increase the average temperature by a maximum 62 K, but delay the gas-phase ignition. Conversely, catalyst segments coated on the trough can advance ignition, but this results in flame elongation and a decrease in the average temperature. The rational combination of catalyst segmentation and sinusoidal-shaped walls facilitates moving the ignition position upstream by a maximum of 0.065 m while substantially reducing the length of the combustor required for complete fuel conversion by more than 60%. These attributes are highly beneficial for improving efficiency and minimizing the length of the micro-combustor for MTPV application.

Introduction:At different times, China has pursued different carbon emission reduction targets, so it is crucial to develop a reasonable and flexible allocation scheme for Chinese carbon emissions quotas, referred to as Chinese Emission Allowance (CEA), in order to achieve carbon reduction goals. As important responsible entities for carbon reduction, each province needs to rely on a well-designed CEA allocation scheme to help achieve their emission reduction goals.Methods:Therefore, based on the utility perspective, this paper constructs allocation principles and methods to formulate the inter-provincial CEA allocation scheme for China in 2030. Specifically, the entropy method, SBM model, improved variable weight function, and ARIMA time series model are sequentially adopted to simulate the re-allocation scheme, examine its rationality, and develop CEA allocation schemes under different principles.Results and Discussion:The following conclusions are drawn: 1) The allocation scheme formulated based on historical emission simulation methods, industry benchmark methods, and other current CEA allocation methods has certain irrationality, and future CEA allocation should not follow the original methods; 2) The improved variable weight function is better suited for allocation in CEA than the current original allocation method. The allocation scheme developed under this method, which balances fairness and efficiency principles, is more appropriate for the actual reduction of carbon emissions in China.

The aims of the study were to identify subclinical global systolic function abnormalities and evaluate influencing factors associated with left ventricular (LV) strain parameters in hypertensive subjects using cardiovascular magnetic resonance imaging feature tracking (CMR-FT). The study enrolled 57 patients with essential hypertension (mean age: 43.04 ± 10.90 years; 35 males) and 26 healthy volunteers (mean age: 38.69 ± 10.44 years; 11 males) who underwent clinical evaluation and CMR examination. Compared with controls, hypertensive patients had significantly impaired myocardial strain values while ejection fraction (EF) did not differ. After multivariate regression analyses adjustment for confounders, the global radial strains (GRS) was independently associated with the mean arterial pressure (MAP) and left ventricular mass index (LVMI) ( β = −0.219, p = 0.009 and β = −0.224, p = 0.015, respectively; Adjusted R 2  = 0.4); the global circumferential strains (GCS) was also independently associated with the MAP and LVMI ( β = 0.084, p = 0.002 and β = 0.073, p = 0.01, respectively; Adjusted R 2 = 0.439); the global longitudinal strains (GLS) was independently associated with the Age and MAP ( β  = 0.065, p  = 0.021 and β  = 0.077, p  = 0.009, respectively; Adjusted R 2  = 0.289). Myocardial strain can early detect the myocardial damage and may be an appropriate target for preventive strategies before abnormalities of EF.

The compressive mechanical properties of a Ti–29Nb–13Ta–4.6Zr alloy were investigated at room temperature under various strain rates. The parameters of a modified Johnson–Cook constitutive equation were determined to describe the strain softening behavior under dynamic conditions. The testing results under compression show yield strength evidently increases with the increase of the strain rate. Moreover, it was found that the strain-rate effect of the yield strength upon dynamic deformation is more significant than that upon quasi-static deformation. In order to characterize the impact-initiated reaction behavior of Ti–29Nb–13Ta–4.6Zr alloy, the quasi-sealed test chamber was used to measure the pressure caused by energy released of fragments. It was obviously shown that the exothermic chemical reaction was more intense with the increase of impact velocity.Graphic Abstract

Background Healthy lifestyle behaviors (LBs) have been widely recommended for the prevention and management of cardiovascular disease (CVD). Despite a large number of studies exploring the association between combined LBs and CVD, a notable gap exists in integration of relevant literatures. We conducted a systematic review and meta-analysis of prospective cohort studies to analyze the correlation between combined LBs and the occurrence of CVD, as well as to estimate the risk of various health complications in individuals already diagnosed with CVD. Methods Articles published up to February 10, 2023 were sourced through PubMed, EMBASE and Web of Science. Eligible prospective cohort studies that reported the relations of combined LBs with pre-determined outcomes were included. Summary relative risks (RRs) and 95% confidence intervals (CIs) were estimated using either a fixed or random-effects model. Subgroup analysis, meta-regression, publication bias, and sensitivity analysis were as well performed. Results In the general population, individuals with the healthiest combination of LBs exhibited a significant risk reduction of 58% for CVD and 55% for CVD mortality. For individuals diagnosed with CVD, adherence to the healthiest combination of LBs corresponded to a significant risk reduction of 62% for CVD recurrence and 67% for all-cause mortality, when compared to those with the least-healthy combination of LBs. In the analysis of dose-response relationship, for each increment of 1 healthy LB, there was a corresponding decrease in risk of 17% for CVD and 19% for CVD mortality within the general population. Similarly, among individuals diagnosed with CVD, each additional healthy LB was associated with a risk reduction of 27% for CVD recurrence and 27% for all-cause mortality. Conclusions Adopting healthy LBs is associated with substantial risk reduction in CVD, CVD mortality, and adverse outcomes among individuals diagnosed with CVD. Rather than focusing solely on individual healthy LB, it is advisable to advocate for the adoption of multiple LBs for the prevention and management of CVD. Trial registration PROSPERO: CRD42023431731. Significance The meta-analysis examined the quantitative correlation between lifestyle behaviors (LBs) and the incidence of cardiovascular disease (CVD) and CVD mortality in the general population, as well as adverse outcomes in CVD patients. The results suggest that healthy LBs are associated with substantial risk reduction in these 3 outcomes. Multiple LBs, instead of tackling one certain LB, should be recommended for the prevention and management of CVD.

Wind velocity distribution and the vortex around the wind turbine present a significant challenge in the development of straight-bladed vertical axis wind turbines (VAWTs). This paper is intended to investigate influence of tip vortex on wind turbine wake by Computational Fluid Dynamics (CFD) simulations. In this study, the number of blades is two and the airfoil is a NACA0021 with chord length of c = 0.265 m. To capture the tip vortex characteristics, the velocity fields are investigated by the Q-criterion iso-surface (Q = 100) with shear-stress transport (SST) k-ω turbulence model at different tip speed ratios (TSRs). Then, mean velocity, velocity deficit and torque coefficient acting on the blade in the different spanwise positions are compared. The wind velocities obtained by CFD simulations are also compared with the experimental data from wind tunnel experiments. As a result, we can state that the wind velocity curves calculated by CFD simulations are consistent with Laser Doppler Velocity (LDV) measurements. The distribution of the vortex structure along the spanwise direction is more complex at a lower TSR and the tip vortex has a longer dissipation distance at a high TSR. In addition, the mean wind velocity shows a large value near the blade tip and a small value near the blade due to the vortex effect.

Background The relationship between high-normal blood pressure (BP) and mortality lacks high-quality evidence based on large population cohorts. This study aims to comprehensively investigate the association of high-normal BP and its trajectory with all-cause and cause-specific mortality. Methods In this community-based population cohort from the China Health Evaluation And risk Reduction Through nationwide teamwork (ChinaHEART) project, 3,598,940 participants aged 35–75 years with data for baseline BP were included. High-normal BP was defined as a systolic BP (SBP) of 130–139 mmHg and/or a diastolic BP (DBP) of 85–89 mmHg at baseline. Overall, 78,130 participants with three or more BP measurements were included in the trajectory pattern analysis during the follow-up. Four BP change trajectory patterns were identified. Results For the baseline BP analysis, compared with the optimal BP group (SBP < 120 mmHg and DBP < 80 mmHg [18.1%]), participants with high-normal BP (18.7%) had an increase of 4% in all-cause mortality risk (hazard ratio [HR] 1.04, 95% confidence interval [CI] 1.01–1.07) and an increase of 28% in cardiovascular disease (CVD) mortality risk (HR 1.28, 95% CI 1.21–1.34), with the greatest increase in mortality risk observed for hemorrhagic stroke (HR 1.75, 95% CI 1.55–1.98). Among the BP trajectory patterns, compared with participants with optimal-stable BP, those with high-normal-increasing BP had an increase of 35% in all-cause mortality risk (HR 1.35, 95% CI 1.07–1.70) and an increase in CVD mortality risk of 57% (HR 1.57, 95% CI 1.11–2.24), with the greatest increase in mortality risk also observed for hemorrhagic stroke (HR 3.75, 95% CI 1.50–9.34). Approximately 0.7% and 1.6% of all-cause mortality was attributable to high-normal BP at baseline and the high-normal-increasing BP trajectory pattern, respectively. Conclusions Individuals with high-normal BP at baseline exhibited a significantly elevated mortality risk and especially for risk of hemorrhagic stroke mortality during the follow-up. This positive association may be mainly attributed to the “high-normal-increasing” BP change over time.

The blade pitch angle has a significant influence on the aerodynamic characteristics of horizontal axis wind turbines. However, few research results have revealed its impact on the straight-bladed vertical axis wind turbine (Sb-VAWT). In this paper, wind tunnel experiments and CFD simulations were performed at the Sb-VAWT to investigate the effect of different blade pitch angles on the pressure distribution on the blade surface, the torque coefficient, and the power coefficient. In this study, the airfoil type was NACA0021 with two blades. The Sb-VAWT had a rotor radius of 1.0 m with a spanwise length of 1.2 m. The simulations were based on the k-ω Shear Stress Transport (SST) turbulence model and the wind tunnel experiments were carried out using a high-speed multiport pressure device. As a result, it was found that the maximum pressure difference on the blade surface was obtained at the blade pitch angle of β = 6° in the upstream region. However, the maximum pressure coefficient was shown at the blade pitch angle of β = 8° in the downstream region. The torque coefficient acting on a single blade reached its maximum value at the blade pitch angle of β = 6°. As the tip speed ratio increased, the power coefficient became higher and reached the optimum level. Subsequently, further increase of the tip speed ratio only led to a quick reversion of the power coefficient. In addition, the results from CFD simulations had also a good agreement with the results from the wind tunnel experiments. As a result, the blade pitch angle did not have a significant influence on the aerodynamic characteristics of the Sb-VAWT.

To investigate the association between preoperative nutritional scores and moderate-to-severe acute kidney injury (AKI) after coronary artery bypass graft (CABG) surgery and the predictive significance of nutritional indices for moderate to severe AKI. This study retrospectively included older patients underwent CABG surgery from the Medical Information Mart for Intensive Care (MIMIC) database. Nutritional scores were calculated by the Geriatric Nutritional Risk Index (GNRI) and the Prognostic Nutritional Index (PNI), respectively. Moderate-to-severe injury was determined by KDIGO criteria. Logistic regression, subgroup analysis, and restricted cubic splines were utilized to investigate the association. The predictive value was also assessed by the area under the curve (AUC), net reclassification index (NRI), and integrated discrimination improvement (IDI). A total of 1,007 patients were retrospectively included, of which 100 (9.9%) and 380 (37.7%) had malnutrition calculated by GNRI and PNI scores. The incidence of moderate-to-severe AKI was 524 (52.0%). After adjustment for selected risk factors, worse nutritional scores were associated with a higher incidence of moderate-to-severe AKI ( <0.001; =0.001). Integrating these indices into different base models improves their performance, as manifested by significant improvements in AUCs and NRIs (  < 0.05). Worse preoperative nutritional status was associated with an elevated risk of postoperative moderate-to-severe AKI. Integrating these indices into base models improve their predictive performance. These results highlight the importance of assessing nutritional status among older patients had CABG surgery.