A ratiometric luminescence sensing platform based on lanthanide-based silica nanoparticles for selective and sensitive detection of Fe3+ and Cu2+ ions.

Detection of Fe(III) and Cu(II) in water is highly desirable because their abnormal levels can cause serious harm to human health and environmental safety. In this work, a ratiometric luminescence sensing platform based on lanthanide-based silica nanoparticles was constructed for the detection of Fe3+ and Cu2+ ions. The terbium-silica nanoparticles (named SiO2@Tb) with dual-emission signals were successfully prepared by grafting Tb3+ ions onto trimellitic anhydride (TMA) functionalized silica nanospheres. It can serve as a ratiometric fluorescent probe for the detection of Fe3+ and Cu2+ ions in water with the green emission of Tb3+ ions as a response signal and the blue emission of silica nanospheres as the reference signal. Significantly, an easy-to-differentiate color change for visual detection was also realized. SiO2@Tb shows high sensitivity even in very low concentration regions towards the sensing of Fe3+ and Cu2+ with low detection limits of 0.75 µM and 0.91 µM, respectively. Moreover, the mechanism for the luminescence quenching of SiO2@Tb was systematically investigated, and was attributed to the synergetic effect of the absorption competition quenching (ACQ) mechanism and cation exchange. This study demonstrates that SiO2@Tb can be employed as a promising fluorescent probe for the detection of Fe3+ and Cu2+ ions, and the combination of lanthanide ions with silica nanoparticles is an effective strategy to construct a ratiometric fluorescent sensing platform for the determination of analytes in environmental detection.

An europium(III) metal-organic framework as a multi-responsive luminescent sensor for highly sensitive and selective detection of 4-nitrophenol and I- and Fe3+ ions in water.

A luminescence sensor based on an europium(III)-based lanthanide-organic framework, [Eu(BCB)(DMF)]·(DMF)1.5(H2O)2 (1), was synthesized via a solvothermal method using 4,4',4''-benzenetricarbonyltribenzoic acid (H3BCB) as a bridging ligand. Single-crystal X-ray diffraction indicates that Eu centers are eight-coordinated with a trigonal dodecahedron and a square antiprismatic configuration, and adjacent Eu atoms are bridged by BCB organic linkers to form a 3D rod-packing structure. Photoluminescence studies show that compound 1 emits bright red luminescence and behaves as a multi-responsive luminescent sensor toward 4-nitrophenol (4-NP) and I- and Fe3+ ions in water with high sensitivity, selectivity and low detection limits. Furthermore, the possible luminescence sensing mechanisms were also investigated by PXRD analysis, UV-vis spectroscopy and X-ray photoelectron spectroscopy (XPS). The recognition mechanism for 4-NP and I- ions can be attributed to the competition absorption and that for Fe3+ ions is considered to be a multi-quenching mechanism dominated by competition absorption. This study demonstrates that the lanthanide-based MOF might be a promising candidate for the detection of 4-NP and I- and Fe3+ ions in aqueous medium.

A terbium(III) lanthanide-organic framework as a selective and sensitive iodide/bromide sensor in aqueous medium.

A potent luminescent sensor for the detection of iodide ions was developed based on a terbium(iii)-based lanthanide-organic framework [Tb(cpia)(H2O)2]n·nH2O (1), which was prepared under hydrothermal conditions using the 5-(4-carboxyphenoxy)isophthalic acid (H3cpia) bridging ligand. Compound 1 exhibits superior luminescence quenching behavior towards I- with high sensitivity and selectivity among various anions and shows real-time response. Moreover, the mechanism of the selective luminescence quenching response for I- can be mainly explained by the absorption competition between 1 and I-. According to this quenching mechanism, we find that compound 1 can also detect Br- by adjusting the excitation wavelength. Significantly, this work could serve as a general guidance for the design and synthesis of pollutant sensors.

Intense pulsed light treatment for Becker's nevus.

BACKGROUND: Becker's Nevus (BN) is a benign hamartoma with an esthetically troublesome condition secondary to hyperpigmentation and hypertrichosis. Many treatment modalities have been utilized with variable outcomes. OBJECTIVES: To evaluate the efficacy and safety of intense pulsed light (IPL) in the treatment of BN. PATIENTS AND METHODS: IPL was used at filter of 590 nm, fluence of 18-22 J/cm2, double-pulse mode (pulse width of 3-10 ms, pulse delay of 20-30 ms) at 3-month intervals. Final evaluations were performed by physician global assessment and patient satisfaction. Side effects were monitored at each treatment session and follow-up visit. RESULTS: Twenty-four patients (9 females, 15 males) with BN (16 hypertrichotic, 8 atrichotic) completed the study. The mean number of treatment sessions was 5 ± 2.17. The improvement in atrichotic BN group (4.87 ± 0.35) was significantly greater than that observed in hypertrichotic BN group (3.63 ± 0.89) (p = .001). Hair density simultaneously decreased with treatment in hypertrichotic BN. The mean satisfaction score was 5.75 ± 2.05 and 8 ± 0.93 in hypertrichotic and atrichotic BN groups respectively (p = .002). No repigmentation was noted during the follow-up period. No permanent side effects were observed. CONCLUSIONS: IPL is an effective and well-tolerated treatment option for patients with hypertrichotic and atrichotic BN.

Research on the evaluation of the resilience of subway station projects to waterlogging disasters based on the projection pursuit model.

To improve sustainable development, increasingly more attention has been paid to the evaluation of the resilience to waterlogging disasters. This paper proposed a projection pursuit model (PPM) improved by quantum particle swarm optimization (QPSO) for the evaluation of the resilience of subway station projects to waterlogging disasters. In view of the lack of research results related to the evaluation of the resilience of subway station projects to waterlogging disasters, 16 secondary indicators that affected the ability of subway station projects to recover from waterlogging disasters were identified from defense, recovery, and adaptability, for the first time. A PPM improved by QPSO was then proposed to effectively deal with the high-dimensional data about the resilience of subway station projects to waterlogging disasters. The QPSO was used to solve the best projection vector of the PPM, and interpolation algorithm was used to construct the mathematical model of evaluation. Finally, four station projects of Chengdu Metro Line 11 in China were selected for a case study analysis. The case study revealed that, among the secondary indicators, the emergency plan of construction order, the exercise frequency of emergency plans, and relief supplies had the greatest weights. The recovery was found to be the most important in the primary indicators. The values of the resilience of Lushan Avenue Station, Miaoeryan Station, Shenyang Road Station, and Tianfu CBD North Station to waterlogging disasters were found to be 2, 1.6571, 2.8318, and 3 respectively. This resilience ranking was consistent with the actual disaster situation in the flood season of 2019. In addition, the case study results showed that QPSO had the advantages of fewer parameter settings and a faster convergence speed as compared with PSO and the genetic algorithm.

Guided Bloch surface wave resonance for biosensor designs.

A guided Bloch surface wave resonance (GBR) configuration is introduced for label-free biosensing. The GBR is realized by coupling the first-order diffraction of a subwavelength grating with the Bloch surface wave at the interface between a 1D photonic crystal slab and bio-solution. In addition to sustaining the Bloch surface mode, the photonic crystal provides the design freedom of simultaneously increasing the quality and decreasing the sideband transmissions of the resonance spectrum. The low sideband and high-quality features along with the large sensitivity rising from the strong overlap between the Bloch surface mode and the bio-solution make the GBR suitable for the design of biosensors. Biosensors with a high figure of merit are realized by the compact configurations.

Efficient production of type 2 porcine circovirus-like particles by a recombinant baculovirus.

The capsid protein of PCV2 was expressed by using a recombinant baculovirus with insect Tn5 cells. A large amount of 28-kDa protein was released into the culture medium and self-assembled into PCV2-like particles (PCV2-LPs) with a buoyant density of 1.365 g/cm(3) and a diameter of 20 nm. PCV2-LPs were efficiently expressed, yielding 1 mg of purified particles per 10(7) Tn5 cells. The PCV2-LPs have antigenicity similar to that of authentic PCV2 particles, allowing us to develop a method for sensitively detecting PCV2-specific IgG antibodies. In addition, the PCV2-LPs appeared to be the most promising PCV2 vaccine candidate, by virtue of their potent immunogenicity.