Studies of a cyanine-based biosensor and light-induced antibacterial activities of oligo(phenylene ethynylene)s

This dissertation has been focusing on two subjects: biosensor development and light-activated antimicrobials. A cyanine-based fluorescent biosensor is developed with high sensitivity to detect the presence and activity of caspase-3/7. We demonstrated that supramolecular self-assembly can be useful for designing biosensors. A series of p-Phenylene Ethynylenes (OPEs) have been synthesized. Further photophysical studies show that these molecules have good singlet oxygen yields. The antimicrobial capability increases dramatically when exposed to UV-365 radiation, though dark biocidal activity can be obtained as well. This phenomenon is probably due to the high yields of singlet oxygen of these OPEs, which oxidizes unsaturated membrane and inner components of bacteria, such as protein, DNA, etc. viii Coupled with our previous work about the interactions of EO-OPE-1s with DOPC/cholesterol vesicles, we believe the biocidal process involves (1) EO-OPE-1s penetrate the bacterial membrane, (2) EO-OPE-1s photosensitize the generation of singlet oxygen and other reactive oxygen species and (3) singlet oxygen and/or reactive oxygen species trigger the cytotoxicity

A Generalized Two-Component Camassa-Holm System with Complex Nonlinear Terms and Waltzing Peakons

In this paper, we deal with the Cauchy problem for a generalized two-component Camassa-Holm system with waltzing peakons and complex higher-order nonlinear terms. By the classical Friedrichs regularization method and the transport equation theory, the local well-posedness of solutions for the generalized coupled Camassa-Holm system in nonhomogeneous Besov spaces and the critical Besov space B5/22,1×B5/22,1 was obtained. Besides the propagation behaviors of compactly supported solutions, the global existence and precise blow-up mechanism for the strong solutions of this system are determined. In addition to wave breaking, the another one of the most essential property of this equation is the existence of waltzing peakons and multi-peaked solitray was also obtained

In-fiber linear polarizer based on UV-inscribed 45° tilted grating in polarization maintaining fiber

We report an in-fiber linear polarizer structured by UV-inscribing a 45° tilted fiber grating (TFG) into polarization maintaining (PM) fiber along its principal axis. The polarization extinction ratio (PER) achieved by a 48 mm long 45° TFG has reached 46 dB at 1550 nm and the overall PER is >40 dB over a 50 nm wavelength range. Such 45° TFG based polarizers have many advantages over conventional products, including low loss, low cost, simple fabrication process, and no physical modification to the fiber, thus offering high stability and capable of handling high power