Fast Detection of the Emetic Toxin Cereulide in Cooked Rice and Dairy Products by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry

A matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) method was developed for the rapid detection of the emetic toxin cereulide in cooked rice and dairy products. The splitting pattern of cereulide standard was analyzed, meanwhile, effects of matrix type, spotting methods, the type and dosage of matrix solvent, and laser intensity on the MS signal intensity of cereulide were investigated. Methodological validation and application to actual samples were conducted. As a result, α-cyano-4-hydroxycinnamic acid (HCCA) was chosen as the matrix and dispersed in a 1:1 acetonitrile-water mixture containing 0.1% trifluoroacetic acid, and the matrix and the samples were sequentially spotted. In MALDI-TOF MS screening of foods using positive ion reflectron and linear modes at 70% laser intensity, the target ion peaks of ([M + Na]+ and [M + K]+) in cereulide were detected with stable signals, high intensity and good response repeatability. The results of methodological validation showed that good linear relationship was observed between the overlapping areas of [M + Na]+ and [M + K]+ peaks and cereulide concentration in the range from 5 to 100 ng/mL, with a correlation coefficients (r) greater than 0.99. The limits of detection (LOD) of [M + Na]+ and [M + K]+ were 3.0 and 5.0 ng/g, respectively; the recoveries of spiked rice and milk samples were ranged from 73.3% to 118.2%, with relative standard deviations (RSDs) of 0.3% to 10.9% (n = 6). This method was characterized by rapidity, high accuracy, good sensitivity, and strong anti-interference ability, and was suitable for the detection of cereulide in cooked rice and dairy products without using any internal standard

Efficient tuning of electroluminescence from sky-blue to deep-blue by changing the constitution of spirobenzofluorene derivatives

Two novel benzimidazole-attached spiro[benzofluorene] derivatives, 2,2'-(spiro[benzo[c]fluorine-7,9'-fluorene]-5,9-diylbis(4,1-phenylene))bis(1-phenyl-1H-benzo[d]imidazole) and 2,2'-(spiro[benzo-[de] anthracene-7,9'-fluorene]-2',3-diylbis(4,1-phenylene))bis(1-phenyl-1H-benzo[d]imidazole), were prepared by a Suzuki coupling reaction. Their photophysical and photochemical properties were studied systemically. The fluorescent organic light-emitting diodes were fabricated by using them as the emitters, all of them showed strong blue emission. Interestingly, from the benzoanthracene derived compound a high color purity was found with Commission de L'Eclairage 1931 chromaticity coordinates of (0.15, 0.10) and an efficiency of 1.96 cd/A. To the best of our knowledge, this is the first time to obtain a deep-blue emission with spiro[benzofluorene] derivative in a nondoped device. (C) 2014 Elsevier Ltd. All rights reserved

Controllable molecular configuration for significant improvement of blue OLEDs based on novel twisted anthracene derivatives

Two novel twisted anthracene derivatives, 2-(4-(10-(phenanthren-9-yflanthracen-9-yl)phenyl)-1-phenyl-1H-phenanthro[9,10-d]-imidazole (p-PABPI) and 2-(3-(10-(phenan-thren-9-yl)anthracen-9-yl)phenyl)-1-phenyl-1H-phenanthro-[9,10-d]imidazole (m-PABPI), have been synthesized. Their photophysical and photochemical properties are also investigated systemically. The non-doped fluorescent organic light-emitting diodes are fabricated by using anthracene derivatives as the emitters. The maximum current efficiencies are achieved to be 3.98 and 132 cd A(-1) and the maximum power efficiencies are 2.80 and 1.14 Im W-1, respectively. The external quantum efficiency maximum (EQEmax) is 3.61% and 1.33% for p-PABPI and m-PABPI. Intriguingly, the efficiencies of p-PABPI are almost three times larger than that of m-PABPI with only the different molecular configuration. The results revealed a new rule of molecular design based on anthracene derivatives for obtaining high performance blue emission materials. (C) 2015 Elsevier Ltd. All rights reserved

Saturated deep-blue emitter based on a spiro[benzoanthracene-fluorene]-linked phenanthrene derivative for non-doped organic light-emitting diodes

A spiro[benzoanthracene-fluorene] derivative containing a phenanthrene moiety, 2',3-di(phenanthren-9-yl)spiro(benzo[de]anthracene-7,9'-fluorene] (DPSBAF), was prepared by a Suzuki coupling reaction. The photophysical and photochemical properties were investigated systematically. A non-doped organic light-emitting diode using DPSBAF as the emitter achieved a luminance efficiency of 2.18 cd A(-1) with Commission Internationale de l'Ectairage 1931 chromaticity coordinates of (0.15, 0.09). The synthesized spiro[benzoanthracene-fluorene] derivative with a high thermal stability, a glass transition temperature of 210 degrees C and a decomposition temperature of 410 degrees C, shows potential for application in non-doped saturated deep-blue organic light-emitting diodes

Tracking the Local Effect of Fluorine Self-Doping in Anodic TiO₂ Nanotubes

We report herein a study in which we reveal the role of F^– incorporated in the very anodic TiO₂ nanotubes prepared electrochemically from a Ti foil using a fluoride based electrolyte. X-ray absorption near edge structure (XANES), resonant X-ray emission spectroscopy (RXES), and X-ray photoelectron spectroscopy (XPS) have been used to examine the as-prepared and the annealed TiO₂ nanotubes. It is found that the additional electron resulting from the substitution of O^2– by self-doped F^– in the TiO₂ lattice is localized in the t_2g state. Consequently, a localized Ti³⁺ state can be tracked by a d–d energy loss peak with a constant energy of 1.6 eV in the RXES, in contrast to TiO₂ nanostructures where this peak is hardly noticeable when F^– is driven out of the lattice upon annealing

Additional file 1 of RegEMR: a natural language processing system to automatically identify premature ovarian decline from Chinese electronic medical records

Additional file 1

Direct Work Function Measurement by Gas Phase Photoelectron Spectroscopy and Its Application on PbS Nanoparticles

Work function is a fundamental property of a material’s surface. It is playing an ever more important role in engineering new energy materials and efficient energy devices, especially in the field of photovoltaic devices, catalysis, semiconductor heterojunctions, nanotechnology, and electrochemistry. Using ambient pressure X-ray photoelectron spectroscopy (APXPS), we have measured the binding energies of core level photoelectrons of Ar gas in the vicinity of several reference materials with known work functions (Au(111), Pt(111), graphite) and PbS nanoparticles. We demonstrate an unambiguously negative correlation between the work functions of reference samples and the binding energies of Ar 2p core level photoelectrons detected from the Ar gas near the sample surface region. Using this experimentally determined linear relationship between the surface work function and Ar gas core level photoelectron binding energy, we can measure the surface work function of different materials under different gas environments. To demonstrate the potential applications of this ambient pressure XPS technique in nanotechnology and solar energy research, we investigate the work functions of PbS nanoparticles with various capping ligands: methoxide, mercaptopropionic acid, and ethanedithiol. Significant Fermi level position changes are observed for PbS nanoparticles when the nanoparticle size and capping ligands are varied. The corresponding changes in the valence band maximum illustrate that an efficient quantum dot solar cell design has to take into account the electrochemical effect of the capping ligand as well