Novel red phosphorescent polymers bearing both ambipolar and functionalized Ir(III) phosphorescent moieties for highly efficient organic light-emitting diodes.

A series of novel red phosphorescent polymers is successfully developed through Suzuki cross-coupling among ambipolar units, functionalized Ir(III) phosphorescent blocks, and fluorene-based silane moieties. The photophysical and electrochemical investigations indicate not only highly efficient energy-transfer from the organic segments to the phosphorescent units in the polymer backbone but also the ambipolar character of the copolymers. Benefiting from all these merits, the phosphorescent polymers can furnish organic light-emitting diodes (OLEDs) with exceptional high electroluminescent (EL) efficiencies with a current efficiency (η L ) of 8.31 cd A(-1) , external quantum efficiency (η ext ) of 16.07%, and power efficiency (η P ) of 2.95 lm W(-1) , representing the state-of-the-art electroluminescent performances ever achieved by red phosphorescent polymers. This work here might represent a new pathway to design and synthesize highly efficient phosphorescent polymers.

Double knock-in pig models with elements of binary Tet-On and phiC31 integrase systems for controllable and switchable gene expression.

Inducible expression systems are indispensable for precise regulation and in-depth analysis of biological process. Binary Tet-On system has been widely employed to regulate transgenic expression by doxycycline. Previous pig models with tetracycline regulatory elements were generated through random integration. This process often resulted in uncertain expression and unpredictable phenotypes, thus hindering their applications. Here, by precise knock-in of binary Tet-On 3G elements into Rosa26 and Hipp11 locus, respectively, a double knock-in reporter pig model was generated. We characterized excellent properties of this system for controllable transgenic expression both in vitro and in vivo. Two attP sites were arranged to flank the tdTomato to switch reporter gene. Single or multiple gene replacement was efficiently and faithfully achieved in fetal fibroblasts and nuclear transfer embryos. To display the flexible application of this system, we generated a pig strain with Dox-inducing hKRASG12D expression through phiC31 integrase-mediated cassette exchange. After eight months of Dox administration, squamous cell carcinoma developed in the nose, mouth, and scrotum, which indicated this pig strain could serve as an ideal large animal model to study tumorigenesis. Overall, the established pig models with controllable and switchable transgene expression system will provide a facilitating platform for transgenic and biomedical research.

[Synthesis, characterization and photoluminescence properties of (EuxRE1-x)(beta-NTA)3phen complexes].

Two series of solid complexes of EuxRE1-x(beta-NTA)3 phen (RE = Y3+ and Tb3+, x = 0.10, 0.30, 0.50, 0.70, 0.90) were synthesized in alcohol. They were characterized by elemental analysis, IR spectra, molar conductivity, 1H NMR spectra and TG-DTA. The molar conductivity indicated that all the complexes were nonelectrolyte; and 1H NMR spectra and IR spectra showed that the ligand coordinates(double-tooth) with RE3+ ions through the oxygen negative ion of enolic form of beta-NTA and the two nitrogen atoms of phen. The fluorescence properties of these complexes were studied, the results indicated that the chemical bonds have formed by the rare earth ions with the two ligands energy can be transferred from the ligand to the RE3+, and the excited spectra was very wide showing that energy transfer was efficient, the fluorescence emission intensity of 5 D0-->7 F2 transitions in the strongest according to the emission spectra of the complexes. So the authors choose this energy transition as the research object and the results showed that the emission intensity of Eu3+ ion can be enhanced if a part of Eu3+ ions were substituted by Y3+ or Tb3+ ions. But the concentration of the Y3+ or Tb3+ ions can influence the fluorescence emission intensity of the rare earth complexes. The authors changed the concentration of Y3+ and Tb3+ in order to find the proper proportion Finally the authors found that if the x < 0.3 for the complexes EuxY1-x (beta-NTA)3 phen can get higher fluorescence intensity than pure Eu3+ system, but compared with the concentration of Y3+, the proportion of Tb3+ is different. The result showed that if x < 0.5 the authors can get higher fluorescence intensity. In all, at a proper proportion of the doping ions (Y3+ or Tb3+) the authors can get higher fluorescence intensity. This doping method not only decreases the cost of materials, but also enhances the fluorescence intensity, so it has a bright future in practical application.