Latest ArticlesHere, a new designed core/satellite gold nanoprobe was developed for detecting trace mount of benzoyl peroxide (BPO) based on its deboronation. This gold nanoassembly (the BE-AuNPs12/65) was constructed via borate ester formation between large 4-mercaptophenylboronic acid (MPBA) modified AuNPs (the MPBA-AuNPs65, as cores)and smalldopamine modifiedAuNPs (theDPA-AuNPs12, assatellites).Particularly, upon addition of BPO, it would trigger the deboronation for the BE-AuNPs12/65 probes accompanying with distinct color changes from blue, purple to wine red, which implied the disassembly of the core/satellite nanostructure after the breakage of carbon to boron chemical bond. By measuring the absorbance ratio at 665 nm and 545 nm, quantification of BPO was achieved in the range of 10.0-100.0 nmol/L, which could also be easilyobserved bynaked eyes. The nanoprobeutilized a boronate deprotection mechanism and the LSPR properties of AuNPs to provide high selectivity for detecting BPO over similar ROS/RNS with the limit of detection as low as 7.2 nmol/L. The practical applicability of this assay was verified through successful determining BPO in flour samples, which demonstrated its great potentials in food safety field.
A series of structurally novel 1, 3, 4-oxadiazole thioether derivatives (6a-6z) containing a 6-fluoroquinazolinylpiperidinyl moiety were designed and synthesized using pharmacophore hybrid approach, and their structures were fully characterized by 1H NMR, 13C NMR and HRMS spectra. Among them, the structure of compound 6d was further corroborated via single-crystal X-ray diffraction analysis. In vitro antibacterial bioassays showed that compounds 6a, 6g, 6u and 6v possessed EC50 values of 30.4, 30.6, 27.5 and 26.0 μg/mL against phytopathogenic bacterium Xanthomonas oryzae pv. oryzae, respectively, which were significantly superior to that of commercially-available bactericide Bismerthiazol (85.1 μg/mL). Moreover, in vitro antifungal bioassays indicated that seven compounds demonstrated broad-spectrum fungicidal acitivties against six types of phytopathogenic fungi at 50 μg/mL. The present work showed the potential of 1, 3, 4-oxadiazole thioether derivatives carrying a 6-fluoroquinazolinylpiperidinyl moiety as effective antimicrobial agents for crop protection, deserving further investigations in the future.
A novel meroterpenoid, euphoractone (1), was isolated from the extracts of the roots of Euphorbia fischeriana Steud. Its structure was determined by spectroscopic methods and X-ray crystallography. 1 possesses an unusual ent-abietane-phloroglucinol skeleton. The plausible biosynthetic pathway for 1 was proposed.1 showed inhibitory activities against human lung cancer H23 and H460 cells with the IC50 values of 21.07±3.54 and 20.91±4.07 μmol/L.
Developing low-cost and high performance catalysts to replace precious metal based catalysts for oxygen reduction reaction (ORR) is one of the most feasible ways to promote the commercial application of fuel cells. In this work, flower-like CoS and octahedral CoS2 are synthesized by a facile one-pot hydrothermal method without any adjunction of surfactants or follow-up thermolysis, their catalytic performance towards ORR in alkaline electrolyte are comparatively investigated. The results reveal that CoS2 outperforms CoS owing to the higher electron density around S-S bond of S22- in the crystal structure, which promotes the adsorption of oxygen on catalyst surface and facilitates the breakage of O-O bond in oxygen, leading to direct 4-electron transfer ORR. When CoS2 particles are dispersed on the surface of rGO with large surface area, their ORR performance could be further improved.
Lung cancer is the most malignant tumor disease with the highest diagnosis and mortality rate in China. The development of therapeutic drugs is the current research focus. Dai-Bai-Jie is a traditional medicine of the Dai nationality, which is commonly used in the treatment of decreasing swelling, alleviating pain and detoxification. Most of the current researches focused on the component analysis of Dai-Bai-Jie, but few researches studied on its antitumor and pharmacological effect. In this study, we incubated A549 cells with different concentrations of Dai-Bai-Jie. The cell proliferation experiment showed that the DaiBai-Jie solution inhibited the proliferation of A549 cells and caused cell apoptosis. In this work, we confirmed that Dai-Bai-Jie had an inhibitory effect on the proliferation and migration of non-small cell lung cancer A549, which may be used as a novel candidate of anti-tumor therapy for lung cancer patients.
An organocatalytic asymmetric [3+2] cycloaddition of trifluoromethyl-containing azomethine ylides with cyclic 2, 4-dienones was developed. The process enables efficient incorporation of CF3 groups into functionalized spiro[pyrrolidin-3, 2'-oxindoles] in high yields with good to excellent enantio-and diastereoselectivities.
Polymyxin B (PB), as the last-line of defense against multidrug-resistant Gram-negative bacteria, has caused resistance to P. aeruginosa recently. Fortunately, synergistic treatment could preserve the last class of antibiotics and reduce the emergency of drug resistance. Here, we performed a screen of 970 approved drugs synergized with PB against the P. aeruginosa DK2, which is severely resistant to PB, MIC = 512 μg/mL. Encouragingly, we found fluoroquinolones could synergy with PB and achieved an obvious reduction in MIC of PB below the clinical susceptible breakpoint (2 μg/mL). Especially, gemifloxacin achieved the highest synergistic effect with PB, leading to a 4096-fold MIC reduction (reduced from 512 μg/mL to 0.125 μg/mL). Furthermore, synergistic effect was also observed in the combination of gemifloxacin and colistin. Finally, outer membrane permeabilization assay showed that gemifloxacin could increase the permeability of bacterial cell membranes for P. aeruginosa which partly explained the synergy mechanism. These results indicate that fluoroquinolones represent attractive synergists to address the emerging threat of polymyxin-resistant infections.
As an emerging 2D conjugated material, graphitic carbon nitride (CN) has attracted great research attention as important catalytic medium for transforming solar energy. Nanostructure modulation of CN is an effective way to improve catalytic activities and has been extensively investigated, but remains challenging due to complex processes, time consuming or low yield. Here, taking advantage of recent discovered good solvents for CN, a nanoprecipitation approach using poor solvents is proposed for preparation of CN nanoparticles (CN NPs). With simple processes of CN dissolution and precipitation, we can quickly synthesize CN NPs (~40 nm) with a yield of up to 50%, the highest one to the best of our knowledge. As an example of potential applications, the as-prepared CN NPs were applied to photocatalytic degradation of dyes with an evident boosted performance up to 2.5 times. This work would open a new way for batch preparation of nanostructured CN and pave its large-scale industrial applications.
Nowadays, tremendous researches have been focused on the core-shell lipid-polymer nanoparticles (LPNs) due to the advantages of both liposomes and polymer nanoparticles. In this work, LPNs were applied to encapsulate brinzolamide (Brz-LPNs) for achieving sustained drug release, improving drug corneal permeation and enhancing drug topical therapeutic effect. The structure of Brz-LPNs was composed of poly(lactic-co-glycolic) acid (PLGA) nanocore which encapsulated Brz (Brz-NPs) and lipid shell around the core. Brz-LPNs were prepared by a modified thin-film dispersion method. With the parameters optimization of Brz-LPNs, optimal Brz-LPNs showed an average particle size of 151.23±1.64 nm with a high encapsulation efficiency (EE) of 86.7%±2.28%. The core-shell structure of Brz-LPNs were confirmed by transmission electronic microscopy (TEM). Fourier transformed infrared spectra (FTIR) analysis proved that Brz was successfully entrapped into Brz-LPNs. Brz-LPNs exhibited obvious sustained release of Brz, compared with AZOPT® and Brz-LPs. Furthermore, the corneal accumulative permeability of Brz-LPNs significantly increased compared to the commercial available formulation (AZOPT®) in vitro. Moreover, Brz-LPNs (1 mg/mL Brz) showed a more sustained and effective intraocular pressure (IOP) reduction than Brz-LPs (1 mg/mL) and AZOPT® (10 mg/mL Brz) in vivo. In conclusion, Brz-LPNs, as promising ocular drug delivery systems, are well worth developing in the future for glaucoma treatment.
Biomass-derived carbon materials have obtained great attention due to their sustainability, easy availability, low cost and environmentally benign. In this work, bamboo leaves derived nitrogen doped hierarchically porous carbon have been efficiently synthesized via an annealing approach, followed by an etching process in HF solution. Electrochemical measurements demonstrate that the unique porous structure, together with the inherent high nitrogen content, endow the as-derived carbon with excellent lithium/sodium storage performance. The porous carbon annealed at 700 ℃ presents outstanding rate capability and remarkable long-term stability as anodes for both lithium-ion batteries and sodium-ion batteries. The optimized carbon delivers a high discharge capacity of 450 mAh/g after 500 cycles at the current density of 0.2 A/g for LIBs, and a discharge capacity of 180 mAh/g after 300 cycles at the current density of 0.1 A/g for SIBs
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