[en] Graphical abstract: -- Highlights: •The molecularly imprinted polymer capped core–shell AuNPs (MIP-ir-AuNPs) were fabricated as a specific functional SERS substrate. •MIP-ir-AuNPs could be utilized in rapid and selective detection of BPA. •MIP-ir-AuNPs displayed good capability for determination of BPA in real samples. -- Abstract: Surface-imprinted core–shell Au nanoparticles (AuNPs) were explored for the highly selective detection of bisphenol A (BPA) by surface-enhanced Raman scattering (SERS). A triethoxysilane-template complex (BPA-Si) was synthesized and then utilized to fabricate a molecularly imprinted polymer (MIP) layer on the AuNPs via a sol–gel process. The imprinted BPA molecules were removed by a simple thermal treatment to generated the imprint-removed material, MIP-ir-AuNPs, with the desired recognition sites that could selectively rebind the BPA molecules. The morphological and polymeric characteristics of MIP-ir-AuNPs were investigated by transmission electron microscopy and Fourier-transform infrared spectroscopy. The results demonstrated that the MIP-ir-AuNPs were fabricated with a 2 nm MIP shell layer within which abundant amine groups were generated. The rebinding kinetics study showed that the MIP-ir-AuNPs could reach the equilibrium adsorption for BPA within 10 min owning to the advantage of ultrathin core–shell nanostructure. Moreover, a linear relationship between SERS intensity and the concentration of BPA on the MIP-ir-AuNPs was observed in the range of 0.5–22.8 mg L⁻¹, with a detection limit of 0.12 mg L⁻¹ (blank ± 3 × s.d.). When applied to SERS detection, the developed surface-imprinted core–shell MIP-ir-AuNPs could recognize BPA and prevent interference from the structural analogues such as hexafluorobisphenol A (BPAF) and diethylstilbestrol (DES). These results revealed that the proposed method displayed significant potential utility in rapid and selective detection of BPA in real samples

[en] Progress in electrochromic lithium ion batteries (LIBs) is reviewed, highlighting advances and possible research directions. Methods for using the LIB electrode materials’ magnetic properties are also described, using several examples. Li_4Ti_5O_1_2 (LTO) film is discussed as an electrochromic material and insertion compound. The opto-electrical properties of the LTO film have been characterized by electrical measurements and UV–Vis spectra. A prototype bi-functional electrochromic LIB, incorporating LTO as both electrochromic layer and anode, has also been characterized by charge– discharge measurements and UV–Vis transmittance. The results show that the bi-functional electrochromic LIB prototype works well. Magnetic measurement has proven to be a powerful tool to evaluate the quality of electrode materials. We introduce briefly the magnetism of solids in general, and then discuss the magnetic characteristics of layered oxides, spinel oxides, olivine phosphate LiFePO_4, and Nasicon-type Li_3Fe_2(PO_4)_3. We also discuss what kind of impurities can be detected, which will guide us to fabricate high quality films and high performance devices. (topical review)

[en] The authors report on a one-pot approach for synthesizing highly fluorescent protamine-stabilized gold nanoclusters. These are shown to be a viable nanoprobe for selective and sensitive fluorometric determination of lead(II) via quenching of fluorescence via Pb(II)-Au(I) interaction. Under optimized conditions, fluorescence measured at excitation/emission peaks of 300/599 nm drops in the 80 nM–15 μM lead(II) concentration range. The detection limit is 24 nM, and relative standard deviations (for n = 11) at concentrations of 0.10, 4.0 and 15 μM are 1.6, 2.5 and 1.9%, respectively. The relative recoveries of added lead(II) in the water samples ranged from 97.9 ± 2.29% to 101.2 ± 1.83%. .

[en] We investigate theoretically the photoassociation dynamics of ultracold "8"5Rb atoms driven by second- and third-order phase-modulated laser fields. The interplay between the second-order and third-order terms of the phase-modulated pulse has an obvious influence on photoassociation dynamics. The different combinations of the second-order and third-order phase coefficients lead to different pulse shapes. Most of the molecular population in the excited electronic state driven only by the third-order phase pulses can be distributed in a single vibrational level. The second-order term of the phase-modulated pulse can change the instantaneous frequency, and therefore the final population is distributed on several resonant vibrational levels, instead of concentrating on a single level. Although the second- and third-order phase-modulated pulse covers more resonant vibrational levels, the total population on the resonant vibrational levels is much smaller than that controlled only by the third-order phase pulse. In particular, the third-order term of the phase-modulated pulse can weaken the ‘multiple interaction’ to some degree. (paper)

[en] Anomalous transport properties of 40-nm-thick single-crystal Bi(111) films grown on Si(111)-7 × 7 substrates is investigated. The magnetoresistance (MR) of the films in perpendicular magnetic field shows a regular positive behavior in the temperature range 2–300K, the MR in parallel field (B_||) displays a series of interesting features. Specifically, we observe a change of the MR (B_||) behavior from positive to negative when the temperature is below 10K. In the range 10–170 K, the MR (B_||) is negative in the investigated field of 9T. When T > 170 K, a positive MR appears in the high field regime. The low temperature MR(B_||) behavior in the parallel field can be understood by the competition between weak localization and weak anti-localization (WAL). Furthermore, our results suggest that the WAL is dominated by the interface carriers

[en] A highly efficient and facile method has been described for the synthesis of quinoxaline derivatives in good to excellent yields (80-99%) by condensation reaction of heterocyclic as well as aliphatic 1,2-diketones (R¹COCOR¹, R¹ = Et, Ph, p-MeC₆H₅, p-MeOC₆H₅, Furyl) with 1,2-diamines (1,2-(NH₂)₂C₆H₃R², R² = H, Br, NO₂, PhCO). A systematic study was carried out to examine the influence of reaction media and electronic factors of the substrates on the reaction results. (author)

[en] We have investigated the resonant properties of a composite meander wire array, which is composed of physically connected ‘metamolecules’ each with two face-to-face hetero-connected split-ring resonators (SRRs). The hybridization of the symmetric modes and antisymmetric modes of the two hetero-connected SRRs results in four resonant modes in the isolated ‘metamolecule’. In the chain case however, only the hybridized symmetric modes, the so-called optical modes, exist, leading to the observed trapped modes. These two trapped modes show an opposite frequency shift between the chain and isolated metamolecule. Numerical simulations and a theoretical analysis based on the hybridization model are used to interpret the underlying physics of the above observation. Our results provide a further understanding of the hybridization effect in complex metamaterials. The continuous morphology of our double-chain structure may be applied tp the design of reconfigurable metamaterials and flexible devices. (paper)

[en] Various methods have been developed in recent years for the determination of uranyl ion by making use of uranyl-specific DNAzymes. However, many of them suffer from hydrolysis by nucleases present in samples such as body fluids. We report here on an uranyl-specific nuclease-resistant DNA aptamer (UApt) as the recognition element, and how gold nanoparticles (AuNPs) can be used as signal reporters in the respective assay. The presence of uranyl ion leads to a conformational change of UApt, and this results in the dispersion of AuNPs and a decrease in the intensity of resonance light scattering (RLS) at around 573.0 nm. The conformational changes were also studied by polyacrylamide gel electrophoresis, circular dichroism, and UV–vis spectroscopy. The RLS signals are linearly related to the concentration of uranyl ion in the 22 to 550 nM range, with a detection limit of 6.7 nM. This method is more simple and robust than others owing to use of a UApt without a ribonucleotide adenosine. It has been successfully applied to the determination of uranyl ion in real samples. We presume that this method may be extended to the determination of other analytes by making use of the corresponding aptamer for the target. (author)

[en] This work describes a method for the determination of 1-hydroxypyrene (OH-Py) via aggregation-induced quenching of the emission of protamine-coated gold nanoclusters using 9-hydroxyphenanthrene (OH-Phe) as a sensitizer to boost the emission efficiency of nanoprobe. Under optimum conditions, the drop in fluorescence intensity at excitation/emission wavelengths of 300/596 nm is proportional to the concentrations of OH-Py in the range from 1.0 to 65 nM. The relative standard deviations are 4.2, 2.4 and 1.9% (for n = 11) at concentration levels of 8.0, 32 and 48 nM of OH-Py, respectively. The detection limit is 0.3 nM which is much lower than that of some previously reported methods. The recoveries from urine samples spiked with OH-Py ranged between 94.4 and 98.8%.

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[en] Structures and dynamics of two-dimensional dust lattices with and without Coulomb molecules in plasmas are investigated. The experimental results show that the lattices have the crystal-like hexagonal structures, i.e. most particles have six nearest-neighboring particles. However, the lattice points can be occupied by the individual particles or by a pair of particles called Coulomb molecules. The pair correlation function is used to compare the structures between the lattices with or without the Coulomb molecules. In the experiments, the Coulomb molecules can also decompose and recombine with another individual particle to form a new molecule. (physics of gases, plasmas, and electric discharges)