New Methylene Blue Covalently Functionalized Graphene Oxide Nanocomposite as Interfacial Material for the Electroanalysis of Hydrogen Peroxide.

New methylene blue (NMB), a phenothiazine dye, was covalently bonded to graphene oxide (GO) using glutaraldehyde as a crosslinking agent, which was characterized by spectroscopic techniques and electrochemistry. The obtained GO-NMB nanocomposite was used as interface material to construct a novel electrochemical sensor for the determination of hydrogen peroxide (H2O2). The electrochemical sensor based on GO-NMB nanocomposite exhibited excellent electrocatalytic activity for the reduction of hydrogen peroxide (H2O2), which was also enhanced by GO within the GO-NMB nanocomposite. With the optimized experimental conditions, the developed sensor showed high sensitivity (79.4 µA mM-1 cm-2) for electrocatalytic determination of H2O2 at the applied potential of -0.50 V in the concentration range of 0.000333 to 2.28 mΜ. The low limit of detection (1.35 µM), good reproducibility, and high stability of the sensor suggests that the electrochemical sensor based on the GO-NMB nanocomposite possesses obvious advantages, which paves a new avenue to functionalize GO for obtaining electrode interface materials.

Mechanism of upconversion luminescence enhancement in Yb3+/Er3+ co-doped Y2O3 through Li+ incorporation.

Li+ doping is a well-known, simple, yet efficient strategy to optimize the properties of upconverting materials. Nonetheless, the position of Li+ in the lattice and the mechanism of upconversion enhancement are still controversial, especially in Yb3+/Er3+ co-doped Y2O3. This paper presents a comprehensive investigation of the above issues (i.e. the position occupied by Li+ in the lattice and the mechanism of luminescence enhancement, in terms of decreased defects) by studying (Y0.78-XYb0.20Er0.02LiX)2O3 powders. Neutron powder diffraction was employed for the first time in the literature to show that Li+ ions are accommodated in Y sites of YO6 octahedra, confirmed also by the content of oxygen defects, which was increased with the increase of Li+ concentration. FT-IR showed that there was a small change in the amount and the type of the surface-absorbed groups with the increase in the Li+ content, thus not supporting the prevailing conclusion that the quenching groups are decreased by doping Li+. Positron annihilation lifetime (PLAS) experiments showed that the total defect concentration and the large defect clusters, which are considered as quenching centers, are decreased with increasing Li+-content, resulting in the enhancement of the emission intensity in Yb3+/Er3+ co-doped Y2O3.

First-in-man implantation of the retrievable and repositionable VenusA-Plus valve.

BACKGROUND: No retrievable and repositionable second generation transcatheter aortic valve is available in China. Here, we report the first-in-man implantation of the retrievable and repositionable VenusA-Plus valve. METHODS: A 76-year-old patient with symptomatic severe aortic stenosis and high surgical risk (STS 13.8%) was recommended for transcatheter aortic valve replacement (TAVR) by heart valve team. Type 0 bicuspid aortic valve with asymmetric calcification was identified by dual source computed tomography, and the unfavorable anatomies increased the possibility of malposition and paravalvular leakage during TAVR. Therefore, we used the retrievable and repositionable VenusA-Plus valve for the patient. RESULTS: Transfemoral TAVR was performed under local anesthesia with sedation, and a 26mm VenusA-Plus valve was successfully implanted. No transvalvular pressure gradient and trace paravalvular leakage were found. CONCLUSION: The successful first-in-man implantation indicates the retrievable and repositionable VenusA-Plus valve is feasible in complicated TAVR cases such as bicuspid aortic valve.

Intrinsic multiferroics in an individual single-crystalline Bi5Fe0.9Co0.1Ti3O15 nanoplate.

In recent years, much attention has been paid to layer-structured Bi4Bim-3Fem-3-xMxTi3O3m+3 (BFMTO, M = Co, Mn) compounds due to their potential as high temperature single phase multiferroic materials. However, BFMTO single crystals have been rarely reported in the past, though they are better candidates for studying the corresponding intrinsic multiferroics as well as the platform for making future devices, due to their structural complexity and difficulties in fabrication. In this article, Bi5Fe0.9Co0.1Ti3O15 single-crystalline nanoplates were synthesized by the hydrothermal method. The ferromagnetic domain structure of the nanoplate was investigated by electron holography. Denser phase contours were observed and the closed magnetic flux lines indicated a significant magnetic interaction between the neighboring nanoplates, which proved the ferromagnetic nature of the sample. Furthermore, M-H loops of the sample were also measured, in which the ferromagnetic Curie temperature reached ∼730.2 K. Besides, ferroelectric domains were also detected by using a piezoresponse force microscope. All the above-mentioned results indicate the first verification of the room temperature (RT) multiferroic behaviour in such single crystals, which will be useful for both future devices and understanding the underlining physics.

[Synthesis of thienopyridine derivatives and its anti-platelet activity in vivo].

To explore novel ADP receptor inhibitors with anti-thrombotic activity, eighteen compounds were synthesized and their structures were confirmed by 1H NMR and MS. The results showed that the activity of compound C1 was superior to ticlopidine in platelet aggregation inhibition tests in vivo and worthy for further investigation. Compounds A4, B2, C4 and C7 possessed moderate platelet aggregation inhibitory activities.

3-Bromo-propyl 2-(2-chloro-phen-yl)-2-(4,5,6,7-tetra-hydro-thieno[3,2-c]pyridin-5-yl)acetate.

In the crystal structure of the title compound, C(18)H(19)BrClNO(2)S, weak C-H⋯O inter-actions help to establish the packing.

2-Chloro-ethyl 2-(2-chloro-phen-yl)-2-(4,5,6,7-tetrahydro-thieno[3,2-c]pyridin-5-yl)acetate.

The mol-ecular packing of the title compound, C(17)H(17)Cl(2)NO(2)S, is stabilized by weak C-H⋯O and C-H⋯Cl inter-actions. The ester chain is almost planar with a mean deviation of 0.0605 Šand makes dihedral angles of 71.60 (4) and 74.70 (8)° with the benzene ring and the thio-phene ring, respectively. The benzene and thio-phene rings make a dihedral angle of 84.22 (7)°.