This letter presents a regression-based speech enhancement framework using deep neural networks (DNNs) with a multiple-layer deep architecture. In the DNN learning process, a large training set ...ensures a powerful modeling capability to estimate the complicated nonlinear mapping from observed noisy speech to desired clean signals. Acoustic context was found to improve the continuity of speech to be separated from the background noises successfully without the annoying musical artifact commonly observed in conventional speech enhancement algorithms. A series of pilot experiments were conducted under multi-condition training with more than 100 hours of simulated speech data, resulting in a good generalization capability even in mismatched testing conditions. When compared with the logarithmic minimum mean square error approach, the proposed DNN-based algorithm tends to achieve significant improvements in terms of various objective quality measures. Furthermore, in a subjective preference evaluation with 10 listeners, 76.35% of the subjects were found to prefer DNN-based enhanced speech to that obtained with other conventional technique.
The layered transition‐metal‐oxide materials are one type of promising cathode materials for sodium‐ion batteries, which typically include P2, P3, and O3 phases, and each has its own advantages and ...challenges. Taking into account the complementarity of each single‐phase structure, constructing the composite structures is an efficient pathway to stabilize the structure and improve the electrochemical performance. Herein, three composite cathode materials owning the phase structures of P3/P2, P2/O3, and P3/P2/O3 are prepared by changing the calcinating conditions without introducing any doping element. Among them, the composite of P3/P2/O3 shows the best capacity retention of 80 mAh g–1 after 200 cycles and the highest rate performance of 100 mAh g–1 at a current density of 750 mA g–1. The improved electrochemical performance can be attributed to the staggered arrangement of different phase structures and the gradient Na‐extraction/intercalation voltages of different phases. The slip of the transition metal layer is subjected to the constraint of the adjacent phase structure, thus inhibiting the phase transformation for capacity fading. This work provides an easy way for the preparation of composite cathode structures and brings a clear case for understanding the advantage of composite structures on electrochemical performance.
Undoped bi‐phase and tri‐phase cathode materials for sodium‐ion batteries are prepared to investigate the exclusive contributions of the multi‐phase structure on electrochemical performance, in which, the tri‐phase cathode show better performance than the bi‐phase cathode and then single‐phase cathode, owing to a structural constraint effect during Na+‐extraction/intercalation and the resulting restricted phase transformations.
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The aim of this study was to identify factors associated with the death of patients with COVID-19 pneumonia caused by the novel coronavirus SARS-CoV-2.All clinical and laboratory parameters were ...collected prospectively from a cohort of patients with COVID-19 pneumonia who were hospitalised to Wuhan Pulmonary Hospital (Wuhan City, Hubei Province, China) between 25 December 2019 and 7 February 2020. Univariate and multivariate logistic regression analysis revealed that age ≥65 years (OR 3.765, 95% CI 1.146–17.394; p=0.023), pre-existing concurrent cardiovascular or cerebrovascular diseases (OR 2.464, 95% CI 0.755–8.044; p=0.007), CD3+CD8+ T-cells ≤75 cells·μL−1 (OR 3.982, 95% CI 1.132–14.006; p<0.001) and cardiac troponin I ≥0.05 ng·mL−1 (OR 4.077, 95% CI 1.166–14.253; p<0.001) were associated with an increase in risk of mortality from COVID-19 pneumonia.” has been corrected to: “Univariate and multivariate logistic regression analysis revealed that age ≥65 years (OR 3.765, 95% CI 1.201−11.803; p=0.023), pre-existing concurrent cardiovascular or cerebrovascular diseases (OR 2.464, 95% CI 1.279−4.747; p=0.007), CD3+CD8+ T-cells ≤75 cells·μL−1 (OR 3.982, 95% CI 1.761–9.004; p<0.001) and cardiac troponin I ≥0.05 ng·mL−1 (OR 4.077, 95% CI 1.778–9.349; p<0.001) were associated with an increase in risk of mortality from COVID-19 pneumonia. In a sex-, age- and comorbid illness-matched case-control study, CD3
CD8
T-cells ≤75 cells·μL
and cardiac troponin I ≥0.05 ng·mL
remained as predictors for high mortality from COVID-19 pneumonia.We identified four risk factors: age ≥65 years, pre-existing concurrent cardiovascular or cerebrovascular diseases, CD3
CD8
T-cells ≤75 cells·μL
and cardiac troponin I ≥0.05 ng·mL
The latter two factors, especially, were predictors for mortality of COVID-19 pneumonia patients.
Despite numerous inherent merits of metal–organic frameworks (MOFs), structural fragility has imposed great restrictions on their wider involvement in many applications, such as in catalysis. Herein, ...a strategy for enhancing stability and enabling functionality in a labile Zr(IV)‐MOF has been proposed by in situ porphyrin substitution. A size‐ and geometry‐matched robust linear porphyrin ligand 4,4′‐(porphyrin‐5,15‐diyl)dibenzolate (DCPP2−) is selected to replace the 4,4′‐(1,3,6,8‐tetraoxobenzolmn3,8phenanthroline‐2,7(1H,3H,6H,8H)‐diyl)dibenzoate (NDIDB2−) ligand in the synthesis of BUT‐109(Zr), affording BUT‐110 with varied porphyrin contents. Compared to BUT‐109(Zr), the chemical stability of BUT‐110 series is greatly improved. Metalloporphyrin incorporation endows BUT‐110 MOFs with high catalytic activity in the photoreduction of CO2, in the absence of photosensitizers. By tuning the metal species and porphyrin contents in BUT‐110, the resulting BUT‐110‐50%‐Co is demonstrated to be a good photocatalyst for selective CO2‐to‐CO reduction, via balancing the chemical stability, photocatalytic efficiency, and synthetic cost. This work highlights the advantages of in situ ligand substitution for MOF modification, by which uniform distribution and high content of the incoming ligand are accessible in the resulting MOFs. More importantly, it provides a promising approach to convert unstable MOFs, which mainly constitute the vast MOF database but have always been neglected, into robust functional materials.
The in situ porphyrin substitution strategy is developed for modifying labile interpenetrated BUT‐109(Zr), affording BUT‐110 with enhanced chemical stability and photocatalytic activity. By tuning the species and contents of metalloporphyrin in BUT‐110, some of the BUT‐110 MOFs may serve as potential photocatalysts for selective CO2‐to‐CO reduction, in the absence of photosensitizer.
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Polychlorinated dibenzo-p-dioxins (PCDDs), as a class of persistent and highly toxic organic pollutants, have been posing a great threat to human health and the environment. The sensing of these ...compounds is important but challenging. Here, we report a highly stable zirconium-based metal-organic framework (MOF), Zr
O
(OH)
(HCOO)
(CPTTA)
(BUT-17) with one-dimensional hexagonal channels and phenyl-rich pore surfaces for the recognition and sensing of two representative PCDDs, 2,3-dichlorodibenzo-p-dioxin (BCDD) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), based on the fluorescence quenching. BUT-17 exhibits high sensing ability with the detection limits as low as 27 and 57 part per billion toward BCDD and TCDD, respectively, and is very selective as well without the interference of similar compounds. The recognition of BUT-17 toward BCDD is demonstrated by single-crystal structure of its guest-loaded phase, in which the fluorescence-quenched complexes form between the adsorbed BCDD molecules and the MOF host through π-π stacking and hydrogen bonding interactions.
As a widely recognized standard regimen, R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone) is able to cure two-thirds patients with diffuse large B cell lymphoma ...(DLBCL), and the remaining patients suffer from refractory or relapsed disease due to resistance to R-CHOP and fare poorly. Unsatisfied outcomes for those relapsed/refractory patients prompted efforts to discover new treatment approaches for DLBCL, including chimeric antigen receptor T cells, bispecific T cell engagers, immunomodulatory drugs, immune checkpoint inhibitors, monoclonal antibodies, antibody-drug conjugates, molecular pathway inhibitors, and epigenetic-modifying drugs. Herein, up-to-date data about the most promising treatment approaches for DLBCL are recapitulated, and novel genetic classification systems are introduced to guide individualized treatment for DLBCL.
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The VIIRS instrument (Visible Infrared Imaging Radiometer Suite) on board the SNPP (Suomi National Polar-orbiting Partnership) satellite contains 11 narrow channels (M1-M11) in the 0.4-2.5 μm solar ...spectral region. The M9 channel is specifically designed for detecting thin cirrus clouds. It is centered at 1.378 μm with a width of 15 nm, which is located within a strong atmospheric water vapor band absorption region. In comparison with the corresponding MODIS Channel 26, the VIIRS M9 channel is narrower and more sensitive for cirrus detections. Because the radiances of the M9 channel over cirrus pixels are subjected to absorption by atmospheric water vapor molecules above and within the cirrus clouds, the water vapor absorption effect needs to be properly taken into consideration when using the M9 channel for quantitative removal of cirrus effects in other VIIRS channels in the 0.4-2.5 μm spectral range. In this article, we describe in detail an empirical technique for the retrieval of cirrus reflectances in the visible and near-IR (VNIR, 0.4-1.0 μm), where ice particles within cirrus clouds have negligible absorption effects, and in shortwave IR (SWIR, 1.0-2.5 μm) where ice particles' absorption effects are observed. The descriptions include all elements leading to the development of the operational VIIRS cirrus reflectance algorithm, the journal literature backing up the approach, theoretical descriptions of the algorithm's physics and mathematical background, and sample retrieval results from the VIIRS data. The SNPP VIIRS cirrus reflectance data products from 1 March 2012 to the present are available from a NASA data center.
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Drawing on the componential model of creativity (Amabile), we examined how shared leadership and a formally appointed leader's transformational leadership jointly cultivate team creativity in two ...studies. We conducted an experiment with a sample of 109 undergraduate students (32 teams) enrolled in a business plan competition (Study 1) and a field survey based on multisource, time‐lagged data collected from 251 full‐time employees working on 64 research and development teams (Study 2). The results from both studies revealed that shared leadership enhanced team members’ individual creative self‐efficacy and individual creativity, which in turn improved team creativity. Moreover, the results from Study 2 showed that a formally appointed leader's use of different transformational leadership behaviors had different impacts on individual and team creativity. Individual‐focused transformational leadership strengthened the positive effect of shared leadership on team members’ average individual creativity, whereas group‐focused transformational leadership facilitated the translation of teams with high average individual creativity into teams with high levels of team creativity. The theoretical and practical implications of the findings are discussed.
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Single‐atom catalysts have demonstrated their superiority over other types of catalysts for various reactions. However, the reported nitrogen reduction reaction single‐atom electrocatalysts for the ...nitrogen reduction reaction exclusively utilize metal–nitrogen or metal–carbon coordination configurations as catalytic active sites. Here, we report a Fe single‐atom electrocatalyst supported on low‐cost, nitrogen‐free lignocellulose‐derived carbon. The extended X‐ray absorption fine structure spectra confirm that Fe atoms are anchored to the support via the Fe‐(O‐C2)4 coordination configuration. Density functional theory calculations identify Fe‐(O‐C2)4 as the active site for the nitrogen reduction reaction. An electrode consisting of the electrocatalyst loaded on carbon cloth can afford a NH3 yield rate and faradaic efficiency of 32.1 μg h−1 mgcat.−1 (5350 μg h−1 mgFe−1) and 29.3 %, respectively. An exceptional NH3 yield rate of 307.7 μg h−1 mgcat.−1 (51 283 μg h−1 mgFe−1) with a near record faradaic efficiency of 51.0 % can be achieved with the electrocatalyst immobilized on a glassy carbon electrode.
Effects of distribution on performance: A single‐atom Fe electrocatalyst supported on nitrogen‐free lignocellulose‐derived graphitic carbon with Fe‐(O‐C2)4 active sites was synthesized and exceptional catalytic activity for N2 reduction to NH3 was demonstrated. The results indicate that the performance of a given catalyst is strongly influenced by factors other than its intrinsic electrocatalytic activity.
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Conjugated microporous polymers (CMPs) have been heralded as promising energy‐storage materials with advantages such as chemical flexibility, porous structure, and environmentally friendliness. ...Herein, a novel conjugated microporous polymer was synthesized by integrating triazine, thiophene, and benzothiadiazole into a polymer skeleton, and the Li+‐storage performance for the as‐synthesized polymer anode in Li‐ion batteries (LIBs) was investigated. Benefiting from the inherent large surface area, plentiful redox‐active units, and hierarchical porous structure, the polymer anode delivered a high Li+ storage capacity up to 1599 mAh g−1 at a current rate of 50 mA g−1 with an excellent rate behavior (363 mAh g−1 at 5 A g−1) and a long‐term cyclability of 326 mAh g−1 over 1500 cycles at 5 A g−1, implying that the newly developed polymer anode offers a great prospect for next‐generation LIBs.
Three for one: A conjugated microporous polymer consisting of triazine, thiophene, and benzothiadiazole, as anode for lithium‐ion batteries shows a high Li+ storage capacity of 1599 mAh g−1 and excellent rate performance as well as long‐term cyclability.
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