Quantum key distribution (QKD)1,2 offers a long-term solution to secure key exchange. Due to photon loss in transmission, it was believed that the repeaterless key rate is bounded by a linear ...function of the transmittance, O(η) (refs. 3,4), limiting the maximal secure transmission distance5,6. Recently, a novel type of QKD scheme has been shown to beat the linear bound and achieve a key rate performance of O(η) (refs. 7–9). Here, by employing the laser injection technique and the phase post-compensation method, we match the modes of two independent lasers and overcome the phase fluctuation. As a result, the key rate surpasses the linear bound via 302 km and 402 km commercial-fibre channels, over four orders of magnitude higher than existing results5. Furthermore, our system yields a secret key rate of 0.118 bps with a 502 km ultralow-loss fibre. This new type of QKD pushes forward long-distance quantum communication for the future quantum internet.Phase-matching quantum key distribution is implemented with a 502 km ultralow-loss optical fibre. The fluctuations of the laser initial phases and frequencies are suppressed by the laser injection technique and the phase post-compensation method.
Background
Accurate glioma grading plays an important role in the clinical management of patients and is also the basis of molecular stratification nowadays.
Purpose/Hypothesis
To verify the ...superiority of radiomics features extracted from multiparametric MRI to glioma grading and evaluate the grading potential of different MRI sequences or parametric maps.
Study Type
Retrospective; radiomics.
Population
A total of 153 patients including 42, 33, and 78 patients with Grades II, III, and IV gliomas, respectively.
Field Strength/Sequence
3.0T MRI/T1‐weighted images before and after contrast‐enhanced, T2‐weighted, multi‐b‐value diffusion‐weighted and 3D arterial spin labeling images.
Assessment
After multiparametric MRI preprocessing, high‐throughput features were derived from patients' volumes of interests (VOIs). The support vector machine‐based recursive feature elimination was adopted to find the optimal features for low‐grade glioma (LGG) vs. high‐grade glioma (HGG), and Grade III vs. IV glioma classification tasks. Then support vector machine (SVM) classifiers were established using the optimal features. The accuracy and area under the curve (AUC) was used to assess the grading efficiency.
Statistical Tests
Student's t‐test or a chi‐square test were applied on different clinical characteristics to confirm whether intergroup significant differences exist.
Results
Patients' ages between LGG and HGG groups were significantly different (P < 0.01). For each patient, 420 texture and 90 histogram parameters were derived from 10 VOIs of multiparametric MRI. SVM models were established using 30 and 28 optimal features for classifying LGGs from HGGs and grades III from IV, respectively. The accuracies/AUCs were 96.8%/0.987 for classifying LGGs from HGGs, and 98.1%/0.992 for classifying grades III from IV, which were more promising than using histogram parameters or using the single sequence MRI.
Data Conclusion
Texture features were more effective for noninvasively grading gliomas than histogram parameters. The combined application of multiparametric MRI provided a higher grading efficiency. The proposed radiomic strategy could facilitate clinical decision‐making for patients with varied glioma grades.
Level of Evidence: 3
Technical Efficacy: Stage 2
J. Magn. Reson. Imaging 2018;48:1518–1528
The authors describe transmission of the novel coronavirus from a woman who had been living for several months in Wuhan, China, to her husband, after her return to their home in Taiwan in January ...2020. No secondary case from this couple has been identified.
The activity and accessibility of MoS2 edge sites are critical to deliver high hydrogen evolution reaction (HER) efficiency. Here, a porous carbon network confining ultrasmall N-doped MoS2 ...nanocrystals (N-MoS2/CN) is fabricated by a self-templating strategy, which realizes synergistically structural and electronic modulations of MoS2 edges. Experiments and density functional theory calculations demonstrate that the N dopants could activate MoS2 edges for HER, while the porous carbon network could deliver high accessibility of the active sites from N-MoS2 nanocrystals. Consequently, N-MoS2/CN possesses superior HER activity with an overpotential of 114 mV at 10 mA cm–2 and excellent stability over 10 h, delivering one of best MoS2-based HER electrocatalysts. Moreover, this study opens a new venue for optimizing materials with enhanced accessible catalytic sites for energy-related applications.
Two‐dimensional (2D) metal–organic framework nanosheets (MOF NSs) play a vital role in catalysis, but the most preparation is ultrasonication or solvothermal. Herein, a liquid–liquid interfacial ...synthesis method has been developed for the efficient fabrication of a series of 2D Ni MOF NSs. The active sites could be modulated by readily tuning the ratios of metal precursors and organic linkers (RM/L). The Ni MOF NSs display highly RM/L dependent activities towards 2e oxygen reduction reaction (ORR) to hydrogen peroxide (H2O2), where the Ni MOF NSs with the RM/L of 6 exhibit the optimal near‐zero overpotential, ca. 98 % H2O2 selectivity and production rate of ca. 80 mmol gcat−1 h−1 in 0.1 M KOH. As evidenced by X‐ray absorption fine structure spectroscopy, the coordination environment of active sites changed from saturation to unsaturation, and the partially unsaturated metal atoms are crucial to create optimal sites for enhancing the electrocatalysis.
2D Ni metal–organic framework nanosheets (MOF NSs) with controlled coordination mode were carefully created through a liquid‐liquid interfacial synthesis strategy for the first time and adopted as efficient electrocatalysts for hydrogen peroxide (H2O2) synthesis. The optimized partially unsaturated Ni MOF NSs‐6 exhibits near‐zero overpotential as well as ca. 98 % H2O2 selectivity in 0.1 M KOH, exceeding most electrocatalysts up to date.
Abstract Disruption of the circadian rhythm contributes to obesity. This study tested the hypothesis that time-restricted feeding (TRF) reduces high-fat diet-induced increase in adiposity. Male ...C57BL/6 mice were fed the AIN93G or the high-fat diet ad libitum (ad lib); TRF of the high-fat diet for 12 or 8 hours during the dark cycle was initiated when high-fat diet-fed mice exhibited significant increases in body weight. Energy intake of TRF 12-hour group was not different from, while that of TRF 8-hour group was slightly but significantly lower than, that of the high-fat ad lib group. Restricted feeding of the high-fat diet reduced body fat mass and body weight compared to mice fed the high-fat diet ad lib . There were no differences in respiratory exchange ratio (RER) among TRF and high-fat ad lib groups, but the RER of these groups were lower than the AIN93G group. Energy expenditure of the TRF groups was slightly but significantly lower than that of the high-fat ad lib group. Plasma concentrations of ghrelin were increased in TRF groups compared to both AIN93G and high-fat ad lib groups. Elevations of plasma concentrations of insulin, leptin, monocyte chemoattractant protein-1 and tissue inhibitor metalloproteinase-1 by high-fat ad lib feeding were reduced by TRF to the levels of mice fed the AIN93G diet. In conclusion, TRF during the dark cycle reduces high-fat diet-induced increases in adiposity and pro-inflammatory cytokines. These results indicate that circadian timing of food intake may prevent obesity and abate obesity-related metabolic disturbance.
Herein, interfacial engineering is demonstrated to improve the thermal stability of non‐fullerene bulk‐heterojunction (BHJ) OPVs to a practical level. An amphiphilic dendritic block copolymer (DBC) ...is developed through a facile coupling method and employed as the surface modifier of ZnO electron‐transporting layer in inverted OPVs. Besides showing distinct self‐assembly behavior, the synthesized DBC possesses high compatibility with plasmonic gold nanoparticles (NPs) due to the constituent malonamide and ethylene oxide units. The hybrid DBC@AuNPs interlayer is shown to improve device's performance from 14.0% to 15.4% because it enables better energy‐level alignment and improves interfacial compatibility at the ZnO/BHJ interface. Moreover, the DBC@AuNPs interlayer not only improves the interfacial thermal stability at the ZnO/BHJ interface but also endows a more ideal BHJ morphology with an enhanced thermal robustness. The derived device reserves 77% of initial PCE after thermal aging at 65 °C for 3000 h and yields an extended T80 lifetime of >1100 h when stored at a constant thermal condition at 65 °C, outperforming the control device. Finally, the device is evaluated to possess a T80 lifetime of over 1.79 years at room temperature (298 K) when stored in an inert condition, showing great potential for commercialization.
An amphiphilic dendritic block copolymer is developed to serve as an efficient surface modifier of ZnO electron‐transporting layer in an organic photovoltaic device. When using an interlayer based on its hybridization with gold nanoparticles, the device can deliver improved performance and possess a lifetime of over 1.79 years when stored at room temperature in inert conditions.
As urbanization accelerates, urban areas play a leading role in energy consumption and CO2 emissions in China. The existing research is extensively concerned with the relationships between ...urbanization, energy consumption and CO2 emissions in recent years, but little attention has been paid to the regional differences. This paper is an analysis of the impact of urbanization on energy consumption and CO2 emissions at the national and regional levels using the STIRPAT model and provincial panel data from 1995 to 2010 in China. The results showed that urbanization increases energy consumption and CO2 emissions in China. The effects of urbanization on energy consumption vary across regions and decline continuously from the western region to the central and eastern regions. The impact of urbanization on CO2 emissions in the central region is greater than that in the eastern region. The impact of urbanization on energy consumption is greater than the impact on CO2 emissions in the eastern region. And some evidences support the argument of compact city theory. These results not only contribute to advancing the existing literature, but also merit particular attention from policy makers and urban planners in China.
► We analyze the impact of urbanization on energy use and CO2 emissions in China. ► Urbanization increases energy consumption and CO2 emissions in China. ► The effects of urbanization on energy use and CO2 emissions vary across regions.
The global existence of smooth solution and the long-time asymptotic stability of the equilibrium to vacuum free boundary problem of the spherically symmetric Euler equations with damping and solid ...core have been obtained for arbitrary finite positive gas constant A in the state equation p=Aργ with p being the pressure and ρ the density, provided that γ>4/3, initial perturbation is small and the radius of the equilibrium R is suitably larger than the radius of the solid core r0. Moreover, we obtain the pointwise convergence from the smooth solution to the equilibrium in a surprisingly exponential time-decay rate. The proof is mainly based on weighted energy method in Lagrangian coordinate.
PDF
