Ag-SiO₂-Er₂O₃ nanocomposites: highly effective upconversion luminescence at high power excitation and high temperature.

Rare Earth (RE) activated upconversion phosphors (UCPs), have demonstrated significant application potentials in some front fields, including solar energy conversion and bio-application. However, some bottleneck problems should be overcame, such as the lower upconversion efficiency, narrower excitation band, concentration-quenching and temperature-quenching. To solve these problems, the Ag-SiO2-Er2O3 nanocomposites were fabricated, in which the upconversion luminescence (UCL) of Er2O3 was white broadband.

[Mammalian DNA methylation and its roles during the induced re-programming of somatic cells].

The technology of induced pluripotent stem cell (iPS) provides the possibility to reverse the terminal differentiated cells to pluripotent stem cells, and is therefore of great importance in both the theoretical research of stem cells and regenerative medicine. However, the efficiency of current induced reprogramming methods is extremely low, and the incomplete reprogramming often happens. It has been reported that some epigenetic memory of the somatic cells exists in these incomplete reprogrammed iPS cells, and DNA methylation, as a relative long-term and stable epigenetic modification, is one of the important factors that influence the efficiency of reprogramming and differentiative capacity of iPS cells.

NaYF4:Yb,Tm nanocrystals and TiO2 inverse opal composite films: a novel device for upconversion enhancement and solid-based sensing of avidin.

Upconversion luminescence (UCL) detection based on rare-earth doped upconversion nanocrystals (UCNCs) as probes has been proved to exhibit a large anti-Stokes shift, no autofluorescence from biological samples, and no photobleaching. However, it is still a challenge to achieve a stable, reproducible solid-based UCL biosensor because of ineffective UCL of the UCNCs. In this work, we fabricated TiO2 inverse opal photonic crystals (IOPCs)/NaYF4:Yb(3+),Tm(3+) (Er(3+)) UCNC composite films, which can tremendously improve the overall UCL of Tm(3+) as high as 43-fold.

Zinc oxide inverse opal electrodes modified by glucose oxidase for electrochemical and photoelectrochemical biosensor.

The ZnO inverse opal photonic crystals (IOPCs) were synthesized by the sol-gel method using the polymethylmethacrylate (PMMA) as a template. For glucose detection, glucose oxidase (GOD) was further immobilized on the inwall and surface of the IOPCs. The biosensing properties toward glucose of the Nafion/GOD/ZnO IOPCs modified FTO electrodes were carefully studied and the results indicated that the sensitivity of ZnO IOPCs modified electrode was 18 times than reference electrode due to the large surface area and uniform porous structure of ZnO IOPCs.

Intense near-infrared quantum cutting emissions in LaF3:Sm3+ nanocrystals.

In this letter, visible to near-infrared (NIR) quantum cutting (QC) luminescence of -20 nm LaF3:Sm3+ (0.2-1 mol%) nanocrystals (NCs) was first studied. A number of novel NIR QC emissions (850-2000 nm) were distinguished.

Effects of reactant rotation on the dynamics of the OH + CH4 → H2O + CH3 reaction: a six-dimensional study.

The dynamics of the hydrogen abstraction reaction between methane and hydroxyl radical is investigated using an initial state selected time-dependent wave packet method within a six-dimensional model. The ab initio calibrated global potential energy surface of Espinosa-García and Corchado was used. Integral cross sections from several low-lying rotational states of both reactants have been obtained using the centrifugal sudden and J-shifting approximations.

Temperature-dependent upconversion luminescence and dynamics of NaYF4:Yb3+/Er3+ nanocrystals: influence of particle size and crystalline phase.

Oleic acid-capped NaYF4:Yb(3+)/Er(3+) upconversion nanocrystals (UCNCs) with different sizes and crystalline phases were prepared, and their temperature-dependent upconversion luminescence (UCL) and dynamics were studied. It is interesting to observe that the temperature-dependent behavior of UCL for the β-phase (25 nm, 45 nm and bulk) and α-phase (<10 nm) UCNCs is quite different. The UCL intensity of Er(3+) ions of the β-phase NaYF4 demonstrates a maximum around 100 K, while the intensity of the α-phase quenches monotonously with elevated temperature (10-400 K).

Simplified microchip electrophoresis for rapid separation of urine proteins.

Background: Urine protein test has been widely used in clinics, but to determine the type of proteinuria is usually difficult due to technical limitations.

Methods: In the current study, a rapid and simple method to separate and determine urine proteins by a microchip electrophoresis (ME) system has been developed in which only 4 min are required.

Results: Optimal separation conditions have been established by using 15 s injection time at 500 and 1,500 V separation voltage in 75 mmol/l borate buffer containing 0.

Controllable chrominance and highly improved luminescent quantum yield of YV(1-x)P(x)O4: Tm, Dy, Eu inverse opal white light phosphors.

In this work, rare earth (RE) ions tri-doped YV(1-x)P(x)O(4): RE(3+) (RE = Tm, Dy, Eu) inverse opal photonic crystals (IOPCs) were fabricated by the PMMA template method, which demonstrated efficient white light emissions under ultraviolet excitation. It is significant to observe that the chrominance of the white light could be largely modulated by the photonic stop band of the IOPCs. And more, the photoluminescence quantum yield in the IOPCs was largely improved over the grinded reference (REF) because the undesired energy transfer (ET) process was effectively restrained.

Synthesis of graphene oxide based CuO nanoparticles composite electrode for highly enhanced nonenzymatic glucose detection.

CuO nanoparticles (NPs) based graphene oxide (CuO/GO) composites with different CuO NPs loading amount as well as pure CuO NPs with different hydrothermal temperatures were synthesized using a hydrothermal method. Transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Raman spectroscopy were employed to characterize the morphology and structures of our samples. The influence of hydrothermal temperature, GO sheet, and loading amount of CuO on particle size and structure of CuO was systemically investigated.

Six-dimensional and seven-dimensional quantum dynamics study of the OH + CH4 → H2O + CH3 reaction.

The reaction dynamics of hydroxyl radical with methane has been investigated using time-dependent wave packet approach within reduced six- and seven-dimensional models. Initial state-selected total reaction probabilities and integral cross sections for the hydrogen abstraction reaction have been computed on the empirical potential energy surface developed by Espinosa-García et al. [J.

Super-intense white upconversion emission of Yb2O3 polycrystals and its application on luminescence converter of dye-sensitized solar cells.

In this Letter, we present the observation of super-intense upconversion (UC) white emission of Yb2O3 under 980 nm excitation, its evolution on excitation power density, the UC mechanism, and its application on the luminescence converter of dye-sensitized solar cells (DSSCs). It is significant to observe that Yb2O3 demonstrates at least one order more intense UC luminescence than β-phase NaYF4:Yb3+, Er3+ and Yb2O3/DSSCs exhibit much better photovoltaic performance than β-phase NaYF4:Yb3+, Er3+/DSSCs under strong excitation. This indicates that Yb2O3 would become a novel candidate of the solar energy converter, especially in the application of concentrator solar cells.

Self assembly of three-dimensional Lu2O3:Eu3+ inverse opal photonic crystals, their modified emissions and dual-functional refractive index sensing.

In this study, Lu2O3:Eu(3+) inverse-opal-photonic crystals (IOPCs) with controllable lattice constants were fabricated using a polymethylmethacrylate (PMMA) template. The modification effect of PC on the (5)D0-(7)F(J) and (5)D1-(7)F(J) (J = 1-6) transitions were systemically studied by emission spectra, luminescent dynamics and the temperature-dependence. It is significant to observe that the increase of (5)D0-(7)F(J) radiative lifetime for Eu(3+) ions (30%) in contrast to the reference sample was mainly due to modulation of the effective refractive index, rather than the density of optical states.

Amphiphilic silane modified NaYF4:Yb,Er loaded with Eu(TTA)3(TPPO)2 nanoparticles and their multi-functions: dual mode temperature sensing and cell imaging.

Rare-earth upconversion nanophosphors (UCNPs) have become one of the most promising luminescent materials for bio-applications, but their use still meets some limitations by difficulties in obtaining biocompatible UCNPs. To address this problem, we have developed a simple and versatile strategy for converting hydrophobic UCNPs into hydrophilic ones by amphiphilic silane modification with ultrathin thickness at room temperature (RT). In this strategy, the coating layers can also afford the place for loading with Eu(TTA)3(TPPO)2 complex which displays down conversion luminescence (DCL).

Glutathione modified gold nanorods with excellent biocompatibility and weak protein adsorption, targeting imaging and therapy toward tumor cells.

The non-specific interaction between the surface of gold nanorods (GNRs) and biomolecules is a significant problem in hyperthermia applications. In this work, a novel surface modification strategy was performed using zwitterionic oxidized glutathione (GSSG) to modify the GNRs through robust Au-S bond formation. The GSSG-GNRs were stable in aqueous solution over a broad range of pH and high ionic strength values.

Communication: excitation band modulation with high-order photonic band gap in PMMA:Eu(TTA)3(TPPO)2 opals.

Changes in the excitation spectra of luminescent species inserted in photorefractive crystals as a function of changes in the high-order photonic band gap (PBG) have not been previously observed. In this communication, we present our results monitoring the excitation band of Eu(TTA)3(TPPO)2 inserted in the PMMA opal photonic crystals as a function of the changes in the high-order PBG of the crystals. We find shifts in the complex excitation band and changes in the integrated emission intensity that correlates with shifts in the high-order PBG through coupling to the excitation transition.

Self-assembly, highly modified spontaneous emission and energy transfer properties of LaPO4:Ce3+, Tb3+ inverse opals.

The modification of photonic crystals (PCs) on photoluminescence of rare earth (RE) ions has attracted considerable interest, however, the modification of PCs on energy transfer (ET) processes of two separate RE centers has not been investigated yet. In this paper, three-dimensional Ce(3+), Tb(3+)-codoped LaPO4 inverse opal PCs (IOPCs) were fabricated by the PMMA colloidal template method. The modification of the photonic stop band (PSB) on emission spectra and the dynamics of the 5d-4f transition of Ce(3+) and the 4f-4f transition of Tb(3+) ions were systematically studied.

Full-dimensional quantum calculations of the vibrational states of H5(+).

Full-dimensional quantum calculations of the vibrational states of H5(+) have been performed on the accurate potential energy surface developed by Xie et al. [J. Chem.

Remarkable enhancement of upconversion fluorescence and confocal imaging of PMMA Opal/NaYF(4):Yb(3+), Tm(3+)/Er(3+) nanocrystals.

Novel PMMA opal photonic crystal/NaYF(4):Yb(3+), Tm(3+)/Er(3+) nanocrystal composites were fabricated and tremendous improvement in upconversion luminescence (UCL) was observed under infrared 980 nm excitation. They were also explored to improve brightness of cell images.

Phase transition, size control and color tuning of NaREF4:Yb3+, Er3+ (RE = Y, Lu) nanocrystals.

It is important to finely tune the upconversion (UC) properties through controlling size and structure of upconversion nanocrystals (UCNCs) and improve their efficiency. Recently, it was reported that the UC luminescence (UCL) intensity of NaLuF4:Yb(3+), Er(3+) UCNCs could be tremendously improved compared to the most efficient NaYF4:Yb(3+), Er(3+) under 980 nm excitation. In this paper, we first studied the varied size control and phase transition properties of NaREF4:Yb(3+), Er(3+) (RE = Y, Lu) UCNCs prepared by the solvothermal method.

Time-dependent wave packet state-to-state dynamics of H/D + HCl/DCl reactions.

The H/D + HCl/DCl (v(0) = 0, j(0) = 0) reactions were investigated in the gas phase using the reactant coordinate based time-dependent wave packet method on the BW2 PES [W. Bian and H.-J.

Inhibited local thermal effect in upconversion luminescence of YVO₄:Yb³⁺, Er³⁺ inverse opals.

Upconversion Luminescence (UCL) of YVO₄:Yb³⁺, Er³⁺ inverse opal photonic crystals (IOPCs) was investigated in contrast to the references under the excitation of a 980-nm laser diode. Besides the traditional modification on UCL and dynamics, it is significant to observe that in the IOPCs the temperature quenching and local thermal effect was greatly suppressed.

Multifunctional Au@mSiO2/rhodamine B isothiocyanate nanocomposites: cell imaging, photocontrolled drug release, and photothermal therapy for cancer cells.

The synthesis of Au@mesoporous SiO(2)/rhodamine B isothiocyanate (Au@mSiO(2)/RBITC) composite nanoparticles (NPs) is presented and their unique biofunctional properties are studied. The structure and morphology of the NPs are characterized by X-ray powder diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. These NPs can not only be functionalized for fluorescence imaging, but also possess well-defined mesopore structures for drug loading and strong infrared surface plasmon absorption for light-controlled drug release and photothermal therapy for cancer cells.

Ultra-broad plasma resonance enhanced multicolor emissions in an assembled Ag/NaYF4:Yb,Er nano-film.

Here, we present the preparation of a Ag/NaYF(4):Yb,Er composite film via a simple assembly method and its considerably enhanced multicolor emissions owing to the strong coupling between the 980 nm excitation light and the ultra-broad surface plasma resonance (SPR) of silver.

12P-conjugated PEG-modified gold nanorods combined with near-infrared laser for tumor targeting and photothermal therapy.

Gold nanorods have been reported as potential tumor photothermal therapy in vivo and in vitro. However, development of the safe and efficient tumor-targeting gold nanorods for in vivo localized tumor therapy is still a challenge. In our present study, we synthesized the PEG modified gold nanorods and demonstrated its negligible cytotoxicity in vitro.