The development of new methods for regio‐ and stereoselective activation of C−O bonds in ethers holds significant promise for synthetic chemistry, offering advantages in terms of environmental ...sustainability and economic efficiency. Moreover, the C−N atropisomers represent a fascinating and crucial chiral system, extensively found in natural products, pharmaceutical leads, and the frameworks of advanced materials. In this work, we have introduced a nickel‐catalyzed regio‐ and enantioselective carbon‐oxygen arylation reaction for atroposelective synthesis of N‐arylisoquinoline‐1,3(2H,4H)‐diones. The high regioselectivity of C−O cleavage benefits from the high stability of the in situ formed (amido)ethenolate via oxidative addition. Additionally, the self‐activation of the aryl C−O bond facilitates the reaction under mild conditions, leading to outstanding enantioselectivities. The diverse post‐functionalizations of the axially chiral isoquinoline‐1,3(2H,4H)‐diones further highlighted the utility of this protocol in preparing valuable C−N atropisomers, including the chiral phosphine ligands.
The effects of Co2O3 addition on the electromagnetic properties of NiCuZn ferrite were investigated, by considering the variation of complex permeability, complex permittivity and quasi-microwave ...absorption property in the 1–1000 MHz frequency range. Results show that the introduction of Co3+ ions in NiCuZn ferrite leads to the marked shifting of magnetic resonance towards high-frequency and a slight increase of the permittivity. These Co-related effects enhance the maximum reflection loss in NiCuZn ferrite to reach −55.1 dB with its absorption bandwidth being tunable in the frequency range 480–1000 MHz, which provides a potential absorber for the anti-electromagnetic interference applications in electronic industry.
Sulfur removal is significant for fuels used as hydrogen source for modern fuel cell applications and to avoid sulfur poisoning of therein used catalysts. Novel membranes for the polymer–zeolite ...system with well-defined transport channels are proposed for the sulfur removal. Membranes are fabricated using polyimide (PI) as matrix material and Y zeolites as adsorptive functional materials. By detailed analysis of FT-IR, morphology and adsorption performance of membranes, the process-structure-function relationship is obtained. The results show that the functional zeolites particles are incorporated into three-dimensional channels. For all cases, the inlet fuel can be desulfurized to below 0.1 mg L−1, which means that the outlet fuel can be used as sulfur-free hydrogen source for fuel cell applications. The proposed membranes adsorber may be applied as sulfur trap before the reformer for fuel cells on-board or on-site, and it may be applied in a periodically replaceable form. The desulfurization efforts by membrane are likely to play an influential role for the development of sulfur-free hydrogen source and fuel cell area.
The well architected three-dimensional membrane channels provided multiple function sites and efficient working way for metal organic frameworks, based which the high performance membrane adsorber with sulfur removal function is expected for modern fuel cell applications. Display omitted
•Membranes are proposed for sulfur-free hydrogen source of fuel cell.•Membrane performance is markedly related with three-dimensional transport channels.•Complexation force has significant influence on the adsorption behavior.
Outdoor traffic-related air pollution has negative effects on respiratory health. In this study, we aimed to explore the effect of outdoor traffic-related air pollution on chronic obstructive ...pulmonary disease (COPD) in Guangzhou.
We enrolled 1,460 residents aged 40 years or older between 21 January 2014 and 31 January 2018. We administered questionnaires and spirometry tests. The distance of participants' residences or locations of outdoor activities from busy roads (as indicators of outdoor traffic-related air pollution), indoor air pollution, and smoking history were queried in the questionnaires.
Of the 1,460 residents with valid survey and test results, 292 were diagnosed with COPD, with a detection rate of 20%. Participants who lived and did their outdoor activities near busy roads had a higher detection rate of COPD. Among residents living at distances of <50 meters, 50-199 meters, and more than 200 meters from busy roads, the detection rates were 20.6, 21.2, and 14.8%, respectively; the rates for outdoor activities at these distances were 23.8, 24.5, and 13.7%, respectively (
< 0.05). After adjusting for sex, age, smoking status, family history, and smoking index, the distance of outdoor activities from busy roads was an independent risk factor for COPD. Participants whose outdoor activities were conducted <50 meters and 50-199 meters of main roads had odds ratios of 1.54 (95% confidence interval 1.01-2.36) and 1.84 (95% interval 1.23-2.76) for the risk of COPD in comparison with a distance of more than 200 meters from busy roads.
Residents of Guangzhou whose outdoor activities were close to busy roads had a high risk of COPD. Traffic-related air pollution presents a risk to human health and a risk of COPD.
Image quality variation is a prominent cause of performance degradation for intelligent disease diagnostic models in clinical applications. Image quality issues are particularly prominent in ...infantile fundus photography due to poor patient cooperation, which poses a high risk of misdiagnosis. Here, we developed a deep learning-based image quality assessment and enhancement system (DeepQuality) for infantile fundus images to improve infant retinopathy screening. DeepQuality can accurately detect various quality defects concerning integrity, illumination, and clarity with area under the curve (AUC) values ranging from 0.933 to 0.995. It can also comprehensively score the overall quality of each fundus photograph. By analyzing 2,015,758 infantile fundus photographs from real-world settings using DeepQuality, we found that 58.3% of them had varying degrees of quality defects, and large variations were observed among different regions and categories of hospitals. Additionally, DeepQuality provides quality enhancement based on the results of quality assessment. After quality enhancement, the performance of retinopathy of prematurity (ROP) diagnosis of clinicians was significantly improved. Moreover, the integration of DeepQuality and AI diagnostic models can effectively improve the model performance for detecting ROP. This study may be an important reference for the future development of other image-based intelligent disease screening systems.
Hierarchically porous SiO
/C hollow microspheres (HPSCHMs) were synthesized by a hydrothermal and NaOH-etching combined route. The adsorption performance of the prepared HPSCHMs was investigated to ...remove Congo Red (CR) in aqueous solution. The results show that the synthesized composite possesses a hollow microspherical structure with hierarchical pores and a diameter of about 100-200 nm, and its surface area is up to 1154 m
g
. This material exhibits a remarkable adsorption performance for CR in solution, and its maximum adsorption amount for CR can reach up to 2512 mg g
. It shows faster adsorption and much higher adsorption capacity than the commercial AC and γ-Al
O
samples under the same conditions. The studies of the kinetics and thermodynamics indicate that the adsorption of CR on the PHSCHM sample obeys the pseudo-second order model well and belongs to physisorption. The adsorption activation energy is about 7.72 kJ mol
. In view of the hierarchically meso-macroporous structure, large surface area and pore volume, the HPSCHM material could be a promising adsorbent for removal of pollutants, and it could also be used as a catalyst support.
In order to investigate the effect of magnetic metal on the absorption performance of metamaterial absorber (MMA), a dual-peak MMA based on magnetic metal nickel is designed and demonstrated in the ...P-band (300–1000 MHz). Two-layer square-ring-metal resonator arrays and two-layer dielectric substrates are arranged alternately with each other to constitute the proposed dual-peak MMA backed with a reflective metal plate. The influences of copper or nickel metallic layers on the absorption coefficients are comparatively analyzed. For the nickel MMA, the dual-peak absorption coefficients of 99.82% and 99.09% are achieved at 394 MHz and 605 MHz, respectively. Moreover, the thickness of dual-peak MMA could be reduced to 9 mm by employing magnetic metal nickel. The physical mechanism of dual-peak absorption is illustrated by surface current distributions, magnetic field distributions and power loss density distributions. The relationship between the changes of geometric dimensions and the shift of peak absorption frequencies is ultimately discussed. These results could provide instructive guidance for realizing a thin dual-peak MMA in the P-band.
A multi-dimensional (1D/2D/3D) carbon/g-C
N
composite photocatalyst (CCN) was successfully prepared by a facile method with carbon from cheap absorbent cotton wool. The activities and stabilities of ...CCN were evaluated by photo-degrading Rhodamine B (RhB) under visible light irradiation. The effect of carbon content in composite on the catalytic activities was investigated. The results show that a good interfacial contact can be observed between g-C
N
and carbon materials in CCN. It reveals an enhanced photocatalytic activity in photocatalytic decomposition of RhB compared with g-C
N
. The carbon content has obvious effect on the performance of CCN, and the optimal carbon content in CCN is 1 wt% (CCN1.0). The first-order rate constant (k) of CCN1.0 is approximately 5.5 and 3.4 times those of g-C
N
and AC1.0/g-C
N
. The CCN1.0 catalyst also shows the excellent photocatalytic stability in the recycling experiments. The enhanced catalytic performance of CCN is mainly due to an increase in electron-hole pair separation efficiency and visible light adsorption after coupling carbon. The hole and •O
radicals are the main active species, and •O
plays a more important role than h
. The photocatalytic mechanism over CCN1.0 was proposed. This work will provide a new insight to prepare highly-efficient g-C
N
-based photocatalysts.
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