Catalytic activation of C-O bonds is considered as a powerful strategy for the production of aromatics from lignin. However, due to the high reduction potentials of diaryl ether 4-O-5 linkage models, their single electron reduction remains a daunting challenge. This study presents the blue light-induced bifunctional N-heterocyclic carbene (NHC)-catalyzed one-electron reduction of diaryl ether 4-O-5 linkage models for the synthesis of trivalent phosphines.
View Article and Find Full Text PDFStacking engineering in van der Waals (vdW) materials is a powerful method to control topological electronic phases for quantum device applications. Atomic intercalation into the vdW material can modulate the stacking structure at the atomic scale without a highly technical protocol. Here we report that lithium intercalation in a topologically structured graphene/buffer system on SiC(0001) drives dynamic topological domain wall (TDW) motions associated with stacking order change by using an in situ aberration-corrected low-energy electron microscope in combination with theoretical modelling.
View Article and Find Full Text PDFWe report the use of halogen bonding (XB) for the generation of aryl radicals from aryl halides under blue light irradiation and applied it in radical generation/1,5-hydrogen-atom transfer/radical cyclization cascade reactions for the synthesis of oxindoles and isoindolinones. On the basis of experimental studies, we propose that DBU can serve as a suitable XB acceptor with aryl halides for the formation of a photoactive electron donor and acceptor complex.
View Article and Find Full Text PDFWe present experimental observations of high order phase contrast in aberration corrected low energy electron microscopy (AC-LEEM). Phase contrast produced by atomic steps on a Ag (111) surface exhibits prominent high order interference fringes, which have not been reported before. These phase contrast features depend upon defocus and incident electron energy, similar to the prominent first order fringes observed previously and in agreement with Fourier optics (FO) model predictions.
View Article and Find Full Text PDFA compact setup with a planar-cathode and grid-anode plus free field drift distance configuration (momentatron) has provided a new way to measure the transverse momentum and, hence, the emittance of the electron beam from a photocathode. This method has been used for analysis of the transverse momentum and emittance of the photoemitted electron beam from the photocathode in a stepwise manner during the fabrication process. The errors caused by the lensing effect from opening holes of the grid anode and misalignments caused by tilting and curving have been systematically analyzed.
View Article and Find Full Text PDFSpin Polarized Low Energy Electron Microscopy (SPLEEM) is a powerful tool to reveal the magnetic structure of ferromagnetic surfaces on the atomic depth scale level[1-3]. With aberration corrected LEEM and a high brightness spin polarized electron gun, high spatial resolution will provide more details for ultra-thin ferromagnetic film studies. This study reports the first realization of aberration corrected SPLEEM (AC-SPLEEM).
View Article and Find Full Text PDFAim And Background: Postoperative nausea and vomiting (PONV) remains a significant clinical problem for surgical patients. Amisulpride is a well-studied DD antagonist that has the potential to be used for preventing and treating PONV. Our aim was to assess the efficacy and safety of amisulpride for prevention and treatment of PONV through a systematic review and meta-analysis.
View Article and Find Full Text PDFThe characterization and control of atomic substitution process is crucial in fabricating high-quality two-dimensional layered compound materials and tuning their physical properties. With intensity-voltage low energy electron microscopy (IV-LEEM), we found that the concentration of copper in the topmost copper silicide monolayer on Si (111) substrates varies gradually from 1.7 to 1.
View Article and Find Full Text PDFBackground: Pediatric chronic pain is relatively common in the world. Although cognitive behavior therapy (CBT) has been shown to be efficacious in children and adolescents, it is generally recognized that availability and accessibility of CBT are limited. While Internet-delivered cognitive-behavioral therapy (ICBT) performs better in these areas.
View Article and Find Full Text PDFVan der Waals (vdW) assembly of layered materials is a promising paradigm for creating electronic and optoelectronic devices with novel properties. Ferroelectricity in vdW layered materials could enable nonvolatile memory and low-power electronic and optoelectronic switches, but to date, few vdW ferroelectrics have been reported, and few in-plane vdW ferroelectrics are known. We report the discovery of in-plane ferroelectricity in a widely investigated vdW layered material, β'-InSe.
View Article and Find Full Text PDFThe effects of space charge, aberrations and relativity on temporal compression are investigated for a compact spherical electrostatic capacitor (α-SDA). By employing the three-dimensional (3D) field simulation and the 3D space charge model based on numerical General Particle Tracer and SIMION, we map the compression efficiency for a wide range of initial beam size and single-pulse electron number and determine the optimum conditions of electron pulses for the most effective compression. The results demonstrate that both space charge effects and aberrations prevent the compression of electron pulses into the sub-ps region if the electron number and the beam size are not properly optimized.
View Article and Find Full Text PDFWe describe the design and commissioning of a novel aberration-corrected low energy electron microscope (AC-LEEM). A third magnetic prism array (MPA) is added to the standard AC-LEEM with two prism arrays, allowing the incorporation of an ultrafast spin-polarized electron source alongside the standard cold field emission electron source, without degrading spatial resolution. The high degree of symmetries of the AC-LEEM are utilized while we design the electron optics of the ultrafast spin-polarized electron source, so as to minimize the deleterious effect of time broadening, while maintaining full control of electron spin.
View Article and Find Full Text PDFZhonghua Yi Xue Za Zhi
April 2012
Objective: To explore the efficacy and safety of tandospirone for adolescents with anxiety disorder.
Methods: In this multicenter open-label 12-week study, a total of 169 adolescents met the criteria of DSM-IV for anxiety disorder were treated with flexible dose of tandospirone. The effects and safety of treatment were assessed by the Hamilton anxiety scale (HAMA), state-trait anxiety inventory (STAI), clinical global impression (CGI) and side effects at baseline and Weeks 2, 4, 8 and 12.
Thioredoxin (Trx) is a member of the thioredoxin protein family and has a conserved catalytic domain (-Trp-Cys-Gly-Pro-Cys-Lys-) with reduction/oxidation (redox) activity. There are two main members in this family, Trx-1, a cytosolic and nuclear form, and Trx -2, a mitochondrial form. Trx-1 is a 104 amino acid multifunctional protein that has been extensively studied.
View Article and Find Full Text PDFBiochem Biophys Res Commun
September 2007
Different cell line with increased thioredoxin-1 (Trx-1) showed a decreased or increased sensitivity to cell killing by cisplatin. Recently, several studies found that the subcellular localization of Trx-1 is closely associated with its functions. In this study, we explored the association of the nuclear Trx-1 with the cisplatin-mediated apoptosis of breast cancer cells MCF-7.
View Article and Find Full Text PDFHybridoma (Larchmt)
June 2007
Monoclonal antibodies (MAbs) against insulin are useful for insulin assays because of their specificity and plentiful supply. We have produced four monoclonal cell strains stably secreting the monoclonal antibodies against insulin; further established subpopulation, titer, affinity; and identified the antibodies as being of subclass IgG(2b)(kappa), one strain, or IgG(1)(kappa), three strains. The smallest detectable level of human insulin by ELISA using this IgG(1) was 1.
View Article and Find Full Text PDFHybridoma (Larchmt)
April 2006
Daintain is a 17-kDa polypeptide originally purified from porcine intestine. This polypeptide is associated with insulin secretion and inflammatory responses. Daintain is highly similar in amino acid sequence to allograft inflammatory factor-1 (AIF-1).
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