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A photochemical synthesis of enol ethers and furan-3(2H)-ones from 1,3-dicarbonyl compounds and aryl diazoacetates has been developed. Significantly, 1,4-dioxane promoted O-alkylation of various 1,3-dicarbonyl compounds beyond previous carbene insertion into C–H and C–C bonds has been disclosed. [ABSTRACT FROM AUTHOR]

Three-dimensional nitrogen-doped graphene (3D-NG) networks, yielded by hydrothermal reaction and freeze-drying treatment, were used as building blocks to construct a metal-free quadruplet electrochemical sensor for simultaneous detection of ascorbic acid (AA), dopamine (DA), uric acid (UA), and acetaminophen (AP). The introduced 3D-NG materials with a 3D porous structure and a nitrogen doping effect were beneficial for the generation of multidimensional electron transfer pathways and the improvement of electrocatalytic activities by modulating their electronic properties, which could contribute to the effective differentiation of the four analytes in their quaternary mixture. Well-resolved oxidation peaks and enhanced response currents of AA, DA, UA, and AP were obtained from the 3D-NG-based electrodes. For the individual determination of one analyte, the linear concentration ranges of AA, DA, UA, and AP were 20–10 000, 1–1000, 0.5–1000, and 0.1–600 μM with detection limits of 3.91, 0.26, 0.12, and 0.02 μM (S/N = 3), respectively. After the synchronous change of the concentrations of AA, DA, UA, and AP, desirable linear relationships were observed in the ranges of 100–7000, 2–600, 1–800, and 10–550 μM with detection limits of 24.33, 0.37, 0.21, and 1.87 μM (S/N = 3), respectively. This sensitive sensing platform was successfully used to monitor AA, DA, UA, and AP in human urine samples, which indicated that 3D-NG could become a promising electrode material for the simultaneous monitoring of multiple electroactive species. [ABSTRACT FROM AUTHOR]

Perylene-bisimide (PDI)-based small molecules (PDI-Ph, PDI-PhCN, PDI-PhCN-2Br and PDI-PhCN-4Br) were synthesized via imidization of perylene bisanhydride and core-bromided perylene bisanhydride. The physical, optical and electronic properties of these molecules were characterized by thermogravimetric analysis (TGA), UV-Vis, X-ray diffraction (XRD), cyclic voltammetry and space charge-limited current (SCLC). PDI-Ph, PDI-PhCN and PDI-PhCN-2Br show excellent thermal stability with decomposition temperatures above 400 °C (610 °C for PDI-PhCN) and high crystallinity with strong π–π stacking. The three molecules also exhibit high electron mobility with average values of 0.169 cm2 V−1 s−1 for PDI-Ph, 0.212 cm2 V−1 s−1 for PDI-PhCN and 0.119 cm2 V−1 s−1 for PDI-PhCN-2Br. Utilizing these molecules as the single electron-transporting layer (ETL), inverted perovskite solar cells with a configuration of ITO/NiOx/MAPbClxI3−x/ETL/Ag were fabricated. A power conversion efficiency of 14.6% was achieved from the device using PDI-PhCN as ETL. Furthermore, when BCP was used as the hole-blocking layer, the identical structured perovskite device achieved a high efficiency of 18.8% for the PDI-PhCN/BCP combination, which was better than the standard cell (17.4%) using C60/BCP as ETL. The superior performance of PDI-PhCN compared to PDI-Ph, PDI-PhCN-2Br and PDI-PhCN-4Br comes from its higher electron mobility and better matched energy levels with that of the absorber MAPbClxI3−x. Our results demonstrate that PDI-based small molecules are very promising electron-transporting materials for highly efficient, low-cost perovskite solar cells. [ABSTRACT FROM AUTHOR]

A split-type photoelectrochemical immunosensor was designed for the ultrasensitive monitoring of prostate-specific antigen (PSA) based on a Cu2+-mediated catalytic reaction for inhibiting the in situ generation of CdS quantum dots (QDs) coupled with the enhancement of the CdS/MoS2 heterojunction; it was constructed by the stepwise modification of MoS2 QDs and CdS QDs onto an ITO electrode surface. In the presence of PSA, CuO NP-labeled anti-PSA antibodies were immobilized onto an anti-PSA antibody-modified 96-well plate via a sandwich immunoreaction and dissolution by hydrochloric acid to obtain a large number of Cu2+ ions. As the Cu2+-triggered catalytic oxidization of glutathione occurred, the in situ growth of CdS QDs as a signal indicator was significantly suppressed, resulting in reduction in the photocurrent response. Under optimal conditions, the biosensor exhibited desirable linearity in the range from 0.5 pg mL−1 to 10 ng mL−1, low detection limit of 0.29 pg mL−1, satisfactory selectivity, and good stability. It was applied to PSA detection in human serum, suggesting a great potential for early diagnostics of some cancers. [ABSTRACT FROM AUTHOR]

Multi-component reactions for the synthesis of polysubstituted thiazoles from simple chemicals are described. Under metal-free reaction conditions, cheap and easily available ketones, aldehydes, ammonium salt, and elemental sulfur are self-assembled to provide entries to three thiazoles in moderate to good yield with a range of functionalities tolerated. [ABSTRACT FROM AUTHOR]

Based on enzymatic biocatalytic precipitation to quench the amplified photocurrent response generated from WS2 nanosheets-sensitized CdS quantum dots heterostructure, a novel photoelectrochemical immunosensor was constructed for sensitive alpha-fetoprotein (AFP) monitoring. The immunosensor comprised an anti-AFP antibody and a horseradish peroxidase-tagged anti-AFP antibody (HRP-Ab2), which served as a capture unit and a signal indicator, respectively. In the presence of AFP, HRP-Ab2 was immobilized on the electrode surface for establishing a sandwich-type immunocomplex via antigen–antibody interaction, and subsequently catalyzed 4-chloro-1-naphthol to form the nonconductive and insoluble precipitate. This precipitation effectively impeded the diffusion and electron transfer of the electron donor, thus achieving decreased photocurrent. Under optimized conditions, excellent linearity range (1 pg mL−1–20 ng mL−1), satisfactory detection limit (0.43 pg mL−1), desirable selectivity and good stability were obtained for the as-designed immunosensor. Moreover, the application of AFP determination in human serum allowed the immunosensor to hold great potential for early diagnostics of some cancer diseases. [ABSTRACT FROM AUTHOR]

An anode catalytic layer for direct methanol fuel cells (DMFCs) with decreased PtRu loading as low as 1.0 mg cm−2 has been prepared by an electrospray method. The morphology of the electrosprayed composite of PtRu/C/Nafion/polyethylene oxide (PEO) is altered from irregular particles to porous microspheres and to nanofibers by adjusting the PEO content. A hybrid structure is assembled using the porous microspheres as the anode catalytic layer for DMFCs, leading to a remarkable enhancement in the maximum power density of 35.4 mW cm−2, which is ∼50% higher than that of the conventional one at the same PtRu loading of 1.0 mg cm−2 and is even comparable to that (31.5 mW cm−2) of the conventional one at a higher PtRu loading of 2.0 mg cm−2. Further investigation reveals that the improved performance is mainly attributed to its hierarchical factual structure. In the primary structure, a single microsphere is with well-distributed PtRu/C and is fully rich in nano-pores and nano-channels, resulting in an increase in the electrochemical active surface area and higher catalyst utilization. In the secondary structure, micro-sized pathways are formed by the stereoscopic microspheres, resulting in enhanced mass transport, higher current density and power density. [ABSTRACT FROM AUTHOR]

A (3,6)-connected metal–organic framework with a fit-3 topology, [CuL(NO3)]·2DMF·H2O (NJU-Bai16), has been synthesized by self-assembly of binuclear [Cu2(COO)2N4] building blocks and heterofunctional ligand 3,5-di(pyridin-4-yl) benzoic acid (HL). The small pores within the framework have enabled their strong interactions with CH4 molecules. NJU-Bai16 was thereby found to exhibit high isosteric heats of CH4 adsorption (23.3 kJ mol−1) and uptake capacity (50.3 cm3 g−1 at 1 bar and 273 K). Additionally, NJU-Bai16 demonstrates high CO2 uptake (22.4 wt% at 1 bar) with excellent selectivity for CO2 over N2 (29.7) at 273 K. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases have threatened human health, amongst which coronary heart disease (CHD) is the third most common cause of death. CHD is considered to be a metabolic disease; however, there is little research on the CHD metabolism. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has enabled the development of a suitable nanomaterial that can be used to obtain considerable high-quality metabolic information without complex pretreatment of biological fluid samples. This study combines SiO 2 @Au nanoshells with minute plasma to obtain metabolic fingerprints of CHD. The thickness of the SiO 2 @Au shell was also optimized to maximize the laser desorption/ionization effect. The results demonstrated 84% sensitivity at 85% specificity for distinguishing CHD patients from controls in the validation cohort.

Phloretin is a dihydrochalcone flavonoid from natural plants, which has protective activities against oxidative stress and inflammation. To date, its effect on diabetic nephropathy (DN) has not been investigated. In this study, we examined the potential role of phloretin in diabetes-induced renal damage and associated mechanisms in a type 2 diabetes mellitus (T2DM) model induced by streptozotocin (STZ) and high-fat diet (HFD) in Apolipoprotein E knockout ( ApoE -/- ) mice. We found that daily treatment with a low dose (20 mg kg -1 ) of phloretin, as a dietary supplement, significantly alleviated polyuria, proteinuria, and glomerular histopathological changes in the T2DM mice, indicating a protective effect of phloretin on diabetic renal dysfunction. In the phloretin-treated T2DM mice, major metabolic parameters, including blood glucose levels, were not altered significantly, suggesting that the observed beneficial effects of phloretin may be due to a mechanism independent of blood glucose control. Further experiments revealed that phloretin had a protective effect on glomerular podocytes as indicated by ameliorated glomerular basement membrane (GBM) thickening and podocyte foot process effacement. Moreover, phloretin treatment restored levels of nephrin and podocin, two podocyte slit diaphragm proteins that were decreased in T2DM mice. Our results indicate that low-dose phloretin treatment has a protective effect on podocytes in DN via a non-hypoglycemic mechanism in preserving nephrin and podocin expression levels. These data suggest that phloretin may be exploited as a novel therapeutic agent for DN.

A split-type photoelectrochemical immunosensor was designed for the ultrasensitive monitoring of prostate-specific antigen (PSA) based on a Cu 2+ -mediated catalytic reaction for inhibiting the in situ generation of CdS quantum dots (QDs) coupled with the enhancement of the CdS/MoS 2 heterojunction; it was constructed by the stepwise modification of MoS 2 QDs and CdS QDs onto an ITO electrode surface. In the presence of PSA, CuO NP-labeled anti-PSA antibodies were immobilized onto an anti-PSA antibody-modified 96-well plate via a sandwich immunoreaction and dissolution by hydrochloric acid to obtain a large number of Cu 2+ ions. As the Cu 2+ -triggered catalytic oxidization of glutathione occurred, the in situ growth of CdS QDs as a signal indicator was significantly suppressed, resulting in reduction in the photocurrent response. Under optimal conditions, the biosensor exhibited desirable linearity in the range from 0.5 pg mL -1 to 10 ng mL -1 , low detection limit of 0.29 pg mL -1 , satisfactory selectivity, and good stability. It was applied to PSA detection in human serum, suggesting a great potential for early diagnostics of some cancers.

Based on enzymatic biocatalytic precipitation to quench the amplified photocurrent response generated from WS2 nanosheets-sensitized CdS quantum dots heterostructure, a novel photoelectrochemical immunosensor was constructed for sensitive alpha-fetoprotein (AFP) monitoring. The immunosensor comprised an anti-AFP antibody and a horseradish peroxidase-tagged anti-AFP antibody (HRP-Ab2), which served as a capture unit and a signal indicator, respectively. In the presence of AFP, HRP-Ab2 was immobilized on the electrode surface for establishing a sandwich-type immunocomplex via antigen-antibody interaction, and subsequently catalyzed 4-chloro-1-naphthol to form the nonconductive and insoluble precipitate. This precipitation effectively impeded the diffusion and electron transfer of the electron donor, thus achieving decreased photocurrent. Under optimized conditions, excellent linearity range (1 pg mL-1-20 ng mL-1), satisfactory detection limit (0.43 pg mL-1), desirable selectivity and good stability were obtained for the as-designed immunosensor. Moreover, the application of AFP determination in human serum allowed the immunosensor to hold great potential for early diagnostics of some cancer diseases.