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[en] To determine Z-score equations and reference ranges for Doppler flow velocity indices of cardiac outflow tracts in normal fetuses. A prospective cross-sectional echocardiographic study was performed in 506 normal singleton fetuses from 18 to 40 weeks. Twelve pulsed-wave Doppler (PWD) measurements were derived from fetal echocardiography. The regression analysis of the mean and the standard deviation (SD) for each parameter were performed against estimated fetal weight (EFW) and gestational age (GA), in order to construct Z-score models. The correlation between these variables and fetal heart rate were also investigated. Strong positive correlations were found between the twelve PWD indices and the independent variables. A linear-quadratic regression model was the best description of the mean and SD of most parameters, with the exception of the velocity time interval (VTI) of ascending aorta against EFW, which was best fitted by a fractional polynomial. Z-score equations and reference values for PWD indices of fetal cardiac outflow tracts were proposed against GA and EFW, which may be useful for quantitative assessment of potential hemodynamic alternations, particularly in cases of intrauterine growth retardation and structural cardiac defects.
[en] Dynamic F-fluorodeoxyglucose (FDG) PET can be used to quantitatively assess the rate of myocardial glucose uptake (MRGlu). The aim of this study was to evaluate the clinical significance and prognostic value of right ventricular (RV) MRGlu in patients with coronary artery disease and heart failure with reduced ejection fraction. Patients with left ventricular ejection fraction (LVEF) ≤ 40% were consecutively enrolled for FDG PET between November 2012 and May 2017. Global LV and RV MRGlu (μmol/min/100 g) were analyzed. Outcome events were independently assessed using electronic medical records to determine hospitalization for revascularization, new-onset ischemic events, heart failure, cardiovascular, and all-cause death. Differences between LV and RV MRGlu and associations with clinical characteristics and echocardiographic data were evaluated. Associations among FDG PET findings and outcomes were analyzed using Kaplan-Meier survival analysis. Seventy-five patients (mean age 62.2 ± 12.7 years, male 85.3%, LVEF 19.3 ± 8.6%) were included for analysis. The mean glucose utilization ratio of RV-to-LV (RV/LV MRGlu) was 89.5 ± 264.9% (r = 0.77, p < 0.001). Positive correlations between RV MRGlu and maximal tricuspid regurgitation peak gradient (r = 0.28, p = 0.033) and peak tricuspid regurgitation jet velocity (r = 0.29, p = 0.021) were noted. LVEF was positively correlated with LV MRGlu (r = 0.27, p = 0.018), but negatively correlated with end-diastolic volume (r = − 0.37, p = 0.001), end-systolic volume (r = − 0.54, p < 0.001), and RV/LV MRGlu (r = − 0.40, p < 0.001). However, RV MRGlu was not well correlated with LVEF. Forty-three patients received revascularization procedures after FDG PET, and 13 patients died in a mean follow-up period of 496 ± 453 days (1–1788 days), including nine cardiovascular deaths. Higher RV and LV MRGlu values, LVEF ≤ 16% and LV end-diastolic volume ≥ 209 ml of gated-PET were associated with poor overall survival and cardiac outcomes. In patients with coronary artery disease and ischemic cardiomyopathy, RV glucose utilization was positively correlated with RV pressure overload, but not LVEF. Global LV and RV MRGlu, LVEF, and LV end-diastolic volume showed significant prognostic value.
[en] Supernovae (SNe) are the most brilliant optical stellar-class explosions. Over the past two decades, several optical transient survey projects discovered more than ∼ 100 so-called superluminous supernovae (SLSNe) whose peak luminosities and radiated energy are ≳ 7 × 1043 erg s−1 and ≳ 1051 erg respectively, at least an order of magnitude larger than those of normal SNe. According to their optical spectra features, SLSNe have been split into two broad categories of type I that are hydrogen-deficient and type II that are hydrogen-rich. Investigating and determining the energy sources of SLSNe would be of outstanding importance for understanding their stellar evolution and explosion mechanisms. The energy sources of SLSNe can be determined by analyzing their light curves (LCs) and spectra. The most prevailing models accounting for the SLSN LCs are the 56Ni cascade decay model, the magnetar spin-down model, the ejecta-circumstellar medium interaction model and the jet-ejecta interaction model. In this review, we present several energy-source models and their different combinations. (invited reviews)
[en] Daphniopsis tibetana Sars lives in elevation, usually with strong solar UV radiation. We speculate that UV may have an effect on the ecology and evolutionary biology of this species. However, the regulatory effect and mechanism of UV on D. tibetana have not been studied previously. Here, our results showed that UVB could act as a positive factor in the relative body lengths, reproductive parameters, and population growth parameters of D. tibetana when UVB radiation is 20–170 mJ cm−2, compared with the control group. Strikingly, these parameters were highest at 120 mJ cm−2. To explore the mechanism underlying the UVB irradiation effects, we conducted a transcriptome analysis using the Trinity platform. The results indicated that differentially regulated genes were mostly enriched in lipid transport and lipid localization by Gene Ontology (GO) enrichment analysis of 146 differentially expressed genes (83 upregulated and 63 downregulated). This is the first study of UVB radiation of D. tibetana to reveal genes that may have crucial roles in survival, growth, and reproduction and could be candidates for future functional studies. Additionally, the study could supply a substantial resource for investigating and elucidating lipids that could play important roles in a physiological context.
[en] Ni@Ag core shell nanowires (NWs) were prepared by in situ chemical reduction of Ag+ around NiNWs as the inner core. Different Ni@Ag NWs with controllable morphologies were achieved through the layer-plus-island growth mode and this mechanism was confirmed by scanning electron microscopy, X-ray fluorescence, and X-ray photoelectron spectroscopy analyses. When used as a catalyst, the synthesized Ni@Ag NWs exhibited high reduction efficiency by showing a high reaction rate constant k of 0.408 s−1 in reducing 4-nitrophenol at room temperature. Besides, combining the magnetic property, including high saturation magnetization and low coercivity, the magnetic NiNW core contributes to excellent recyclability and long-term stability with only a 2.2% performance loss after 10 recycles by magnets. The Ni@Ag NWs proposed here show unprecedentedly high potential in applications requiring high efficiency and a recyclable catalyst. (paper)
[en] Highlights: • Mode 4 has the highest exergy efficiency. • Mode 2 has the largest exergy density. • Second heat exchanger has the largest exergy destruction. - Abstract: Advanced adiabatic compressed air energy storage system plays an important role in smoothing out the fluctuated power from renewable energy. Under different operation modes of charge-discharge process, thermodynamic behavior of system will vary. In order to optimize system performance, four operation modes of charge-discharge process are proposed in this paper. The performance difference of four modes is compared with each other based on energy analysis and exergy analysis. The results show that exergy efficiency of mode 4 is the highest, 55.71%, and exergy density of mode 2 is the largest, 8.09 × 106 J m−3, when design parameters of system are identical. The second heat exchanger has the most improvement potential in elevating system performance. In addition, a parametric analysis and multi-objective optimization are also carried out to assess the effects of several key parameters on system performance.
[en] Large-scale exfoliation of defect-free and few-layer graphene by an inexpensive and environmentally-friendly route has been a significant challenge for a long time. Here we show that high-quality, few-layer graphene with high stability and low defect content can be obtained from natural graphite via a simple stirring process in urea/glycerol, with yields of up to 12 wt.%. We also demonstrate that this facile method can be applied to the exfoliation of other two-dimensional materials, such as molybdenum disulfide and boron nitride. The as-prepared graphene was further composited with polyvinylidene fluoride (PVDF) and the composite exhibited a low percolation threshold of 0.05 vol.%. The incorporation of low (4.5 vol.%) graphene amounts led to a significant increase in the thermal conductivity of the graphene–PVDF composites. .
[en] Transverse localization of the optical Tamm plasmon (OTP) is studied in a metal-distributed Bragg reflector (DBR) structure with a one-dimensional disordered layer embedded at the interface between the metal and the DBR. The embedded disordered layer induces multiple scattering and interference of light, forming the light localization in the transverse direction. This together with the formation of Tamm plasmonic modes at the metal-DBR interface (i.e., the confinement of light in the longitudinal direction), gives birth to the so called transverse-localized Tamm plasmon. It is shown that for both transverse electric (TE) and transverse magnetic (TM) polarized light injection, the excited transverse-localized Tamm plasmon broadens and splits the dispersion curve due to spatial incoherence in the transverse direction, thus proving the stronger light confinement especially in the TE polarized injection. By adding the gain medium, specific random lasing modes are observed. The proposed study could be an efficient way of trapping and locally enhancing light on a subwavelength scale, which is useful in applications of random lasers, optical sensing, and imaging. (special topic)
[en] The simultaneous generation of random lasing and a supercontinuum is demonstrated, where random lasing emission is realized in a completely-opened fiber structure without any resonance, and its wavelength lies in the anomalous dispersion region of a nonlinear fiber. As a result, a forward supercontinuum with a 20 dB bandwidth of ∼200 nm is obtained experimentally. This study provides the simplest structure for the simultaneous generation of pump lasing (random lasing acts as a pump for supercontinuum generation) and a supercontinuum, benefiting from the natural simplicity of completely-opened random fiber laser, and may result in novel supercontinuum sources with excellent reliability and lifetime. (letter)
[en] Highlights: • A chemical bath deposition method was used for synthesis of CdS/BiOI composite. • The removal rate of EE2 over CdS/BiOI composite could approach 100% after 12 min under visible light irradiation. • The Z-scheme mechanism of EE2 degradation by CdS/BiOI was proposed. - Abstract: A novel CdS/BiOI composite has been prepared via a chemical bath deposition method. The physical and chemical properties of as-prepared composites were characterized by XRD, SEM, TEM, EDS, XPS, UV–vis DRS, and PL. The synthesized CdS/BiOI composites exhibited superior photocatalytic activity in photodegrading of 17α-ethinyl estradiol (EE2) compared to pure CdS and pure BiOI, and the removal rate of EE2 could approach 100% after only 12 min of visible light irradiation using 3:1 CdS/BiOI composite as photocatalyst. The reaction rate constant over 3:1 CdS/BiOI composite was 6.3, 7.1 and 70.9 times higher than that of pure CdS, pure BiOI and P25 respectively. In addition, a Z-scheme charge separation mechanism was proposed on the basis of the experimental results and the theoretical calculation. Moreover, the prepared composite showed good stability and recyclability which are beneficial for its practical application.