Understanding the chemical mechanism behind photoinduced enhanced Raman spectroscopy

Photoinduced enhanced Raman spectroscopy (PIERS) is a new surface enhanced Raman spectroscopy (SERS) modality with a 680% Raman signal enhancement of adsorbed analytes over that of SERS. Despite the explosion in recent demonstrations, the PIERS mechanism remains undetermined. Using X-ray and time-resolved optical spectroscopies, electron microscopy, cyclic voltammetry, and density functional theory simulations, we elucidate the atomic-scale mechanism behind PIERS. Stable PIERS substrates were fabricated using self-organized arrays of TiO2 nanotubes with controlled oxygen vacancy doping and size-controlled silver nanoparticles. The key source of PIERS vs SERS enhancement is an increase in the Raman polarizability of the adsorbed analyte upon photoinduced charge transfer. A balance between improved crystallinity, which enhances charge transfer due to higher electron mobility but decreases light absorption, and increased oxygen vacancy defect concentration, which increases light absorption, is critical. This work enables the rational design of PIERS substrates for sensing

GNA11 brain somatic pathogenic variant in an individual with phacomatosis pigmentovascularis

Objective: To describe the findings of histopathology and genotyping studies in affected brain tissue from an individual with phacomatosis pigmentovascularis (PPV). / Methods: A retrospective chart review of a 2-year 10-month-old male with a clinical diagnosis of PPV cesiomarmorata (or type V) was performed. Clinical features, brain imaging and histopathology findings, and genotyping studies in his affected brain tissue are summarized. / Results: The proband had a clinically severe neurologic phenotype characterized by global developmental delay, generalized hypotonia, and recurrent episodes of cardiac asystole in the setting of status epilepticus. A somatic pathogenic variant in GNA11 (c.547C>T, p.Arg183Cys) was detected in his skin tissue but not in blood (previously published). He underwent an urgent left posterior quadrantectomy for his life-threatening seizures. Histopathology of resected brain tissue showed an increase in leptomeningeal melanocytes and abnormal vasculature, and the exact pathogenic variant in GNA11 (c.547C>T, p.Arg183Cys), previously isolated from his skin tissue but not blood, was detected in his resected brain tissue. / Conclusions: The finding of this variant in affected skin and brain tissue of our patient with PPV supports a unifying genetic diagnosis of his neurocutaneous features

Controlled synthesis of high-ortho-substitution phenol-formaldehyde resins

The relationship between the use of 19 kinds of metal catalysts and the proportion of ortho-ortho links of novolac resins was studied. The proportion of ortho-ortho links of novolac resins was characterized with Fourier transform infrared, H-1-NMR, and C-13-NMR. The effects of different catalysts and different reaction conditions, such as the molar ratio of phenol to formaldehyde, the pH value of the reaction, and the reaction time, were examined. Phenolformaldehyde resins were synthesized with a certain proportion of the ortho position through the adjustment of the reaction conditions. (c) 2005 Wiley Periodicals, Inc

The reactivity ratios of group transfer copolymerization of acrylonitrile with methacrylates

Random copolymerization have been performed for three binary systems using 1-methoxy-2-methyl-1-trimethylsilyloxy propene(initiator) and tetrabutylammonium bibenzoate(catalyst) in tetrahydrofuran solution. The copolymer compositions were determined by elementary analysis for nitrogen and the results evaluated by the Kelen-Tudos method, The monomer pairs concerned are (1) acrylonitrile(AN) and methyl methacrylate(MMA), (2) AN and ethyl methacrylate(EMA), (3) AN and butyl methacrylate(BMA), The reactivity ratios determined in this study are: (1) r(AN)=10.22, r(MMA)=0.07; (2)r(AN)= 5.68, r(EMA)=0.16; (3) r(AN)=8.59, r(BMA)=0.09

Self-propelled swimming of a flexible plunging foil near a solid wall

Numerical simulations are conducted to investigate the influences of a solid wall on the self-propelled swimming of a flexible plunging foil. It is found that the presence of a solid wall enhances the cruising speed, with the cost of increasing input power. Rigid foil can achieve high percentage increase in cruising speed when swimming near a solid wall, but the propulsive efficiency may be reduced. Foils with some flexibility can enjoy the enhancements in both cruising speed and propulsive efficiency. Another advantage of the flexible foils in near-wall swimming is that smaller averaged lateral forces are produced. The effects of wall confinement on the wake structure and the vortex dynamics are also studied in this paper. The results obtained in this study shed some light on the unsteady wall effect experienced by aquatic animals and also inform the design of bio-mimetic underwater vehicles which are capable of exploiting the wall effect

Spatial and seasonal distributions of carbonaceous aerosols over China

Author name used in this publication: S. C. LeeAuthor name used in this publication: S. H. Qi2007-2008 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Direct linearly polarized electroluminescence from perovskite nanoplatelet superlattices

Polarized light is critical for a wide range of applications, but is usually generated by filtering unpolarized light, which leads to substantial energy losses and requires additional optics. Here we demonstrate the direct emission of linearly polarized light from light-emitting diodes made of CsPbI3 perovskite nanoplatelet superlattices. The use of solvents with different vapour pressures enables the self-assembly of the nanoplatelets with fine control over their orientation (either face-up or edge-up) and therefore their transition dipole moment. As a result of the highly uniform alignment of the nanoplatelets, as well as their strong quantum and dielectric confinement, large exciton fine-structure splitting is achieved at the film level, leading to pure red light-emitting diodes with linearly polarized electroluminescence exhibiting a high degree of polarization of 74.4% without any photonic structures. This work demonstrates the potential of perovskite nanoplatelets as a promising source of linearly polarized light, opening up the development of next-generation three-dimensional displays and optical communications from a highly versatile, solution-processable system

Search for Charged Higgs Bosons in e+e- Collisions at \sqrt{s} = 189 GeV

A search for pair-produced charged Higgs bosons is performed with the L3 detector at LEP using data collected at a centre-of-mass energy of 188.6 GeV, corresponding to an integrated luminosity of 176.4 pb^-1. Higgs decays into a charm and a strange quark or into a tau lepton and its associated neutrino are considered. The observed events are consistent with the expectations from Standard Model background processes. A lower limit of 65.5 GeV on the charged Higgs mass is derived at 95 % confidence level, independent of the decay branching ratio Br(H^{+/-} -> tau nu)

Glucuronidation by UGT1A1 Is the Dominant Pathway of the Metabolic Disposition of Belinostat in Liver Cancer Patients

10.1371/journal.pone.0054522PLoS ONE81