Topological properties of tetratomic Su-Schrieffer-Heeger chains with hierarchical long-range hopping

We propose a new generalized Su–Schrieffer–Heeger model with hierarchical long-range hopping based on a onedimensional tetratomic chain. The properties of the topological states and phase transition, which depend on the cointeraction of the intracell and intercell hoppings, are investigated using the phase diagram of the winding number. It is shown that topological states with large positive/negative winding numbers can readily be generated in this system. The properties of the topological states can be verified by the ring-type structures in the trajectory diagram of the complex plane. The topological phase transition is strongly related to the opening(closure) of an energy bandgap at the center(boundaries) of the Brillouin zone. Finally, the non-zero-energy edge states at the ends of the finite system are revealed and matched with the bulk–boundary correspondence.

A Brief Introduction to Organic Electrodeposition and a Review of the Fabrication of OLEDs based on Electrodeposition Technology

Electrodeposition is an old and effective method for the fabrication of organic films.Though electrodeposited organic films have been widely used in various applications,highly luminescent films have been a great challenge because the electrochemically doped state may strongly quench the fluorescence.In the first part of this review,the organic electrodeposition techniques,along with general electropolymerization and other special electrodepositions are introduced.In the second part of the review,we describe how to electrochemically fabricate luminescent films for organic light-emitting diodes(OLEDs).With the rational molecular design and well-controlled electrodeposition process,we have not only demonstrated high-performance OLEDs,but also paved a promising way to practice active-matrix OLEDs(AMOLEDs)and super-resolution OLEDs.In particular,RGB 3×3 array OLEDs based on active-matrix substrates,RGB passive-matrix OLEDs(PMOLEDs)with a resolution of 210 ppi,and monochromatic OLEDs with a super-resolution of 2822 ppi have been successfully fabricated.It is highly anticipated that the organic electrodeposition technology is of comparable or perhaps even higher contenders in manufacturing and downscaling OLEDs and AMOLEDs with low-cost and high-resolution for the human-computer interaction fields such as augmented reality(AR),virtual reality(VR),etc.

Caffeine Suppresses Apoptosis of Bladder Cancer RT4 Cells in Response to Ionizing Radiation by Inhibiting Ataxia Telangiectasia Mutated-Chk2-p53 Axis

Background： Caffeine suppresses ataxia telangiectasia and Rad3 related and ataxia telangiectasia mutated （ATM） activities; ATM is the major kinase for DNA damage detection. This study aimed to investigate the effects of caffeine on DNA damage responses in cells from the bladder cancer cell line RT4 those were exposed to ionizing radiation （IR）. Methods： Immunofluorescent staining was performed to investigate changes in the proteins involved in DNA damage responses with or without caffeine. A mouse xenograft model was used to study the effects of caffeine on the DNA damage responses. Western blotting was used to investigate the effects of caffeine pretreatment on the ATM-Chk2-p53-Puma axis, while real-time polymerase chain reaction （RT-PCR） assessed changes in messenger RNA levels of p53 and downstream targets responding to IR. Finally, terminal deoxynucleotidyl transferase-dUTP nick end labeling assay. Western blotting and colony formation assay were used to measure the effects of caffeine on radiation-related apoptosis. All of the data were analyzed with a two-tailed Student＇s t-test. Results： lmmunofluorescent staining showed that caffeine pretreatment profoundly suppressed the formation ofyH2AXand p53-binding protein 1 foci in RT4 cells in response to irradiation. Cellular and animal experiments suggested that this suppression was mediated by suppression of the ATM-Chk2-p53-Puma DNA damage-signaling axis. RT-PCR indicated caffeine also attenuated transactivation of p53 and p53-inducible genes. The colony formation assay revealed that caffeine displayed radioprotective effects on RT4 cells in response to low-dose radiation compared to the radiosensitization effects on T24 cells. Conclusion： Caffeine may inhibit IR-related apoptosis of bladder cancer RT4 cells by suppressing activation of the ATM-Chk2-p53-Puma axis.