The xerographic properties of dual-layer photoreceptors having different molecular structure, are described with respect to their photosensitivities. A correlation between the absorption wavelength and the photosensitivity was found. A study on device optimization of 3,4,9,10-perylenetetracarboxylic diimides was carried out. The dual-layer photoreceptor device exhibited low dark decay and flat spectral response from 450-750 nm. The spectral sensitivity of the dual-layer photoreceptor extends to the near-IR region.

A newly synthesized nitroxide radical,4-ferrocenecarboxyI-2,2,6,6-tetramethyI piperidine-1-oxyl(FC-TEMPO), was firstly encapsulated in the poly(DL-Lactic acid) (PLA) nanoparticles by the modified spontancous emulsification solvent diffusion method. The formation of the nanoparticles with diameters of 120

Novel smart materials can be synthesized and designed at the molecular level by attaching well characterized and tailored functionalities to be used in in vitro and in vivo oximetry. A series of porphyrins and metalloporphyrins were synthesized and their EPR and UV-vis spectra studied. The steric hindrance and electronic effects of the substituted groups and the characteristics of different metal ions were the major contributors in influencing the properties of the compounds. As a result, their EPR and UV-vis spectra changed. Through studying the EPR spectroscopic properties of these compounds, we hope that novel EPR oximetry materials can be found and this will help to extend the applications of EPR oximetry in vivo.

New electron paramagnetic resonance (EPR) oximetry probes were identified in the class of carbon black materials. These compounds exhibit very high oxygen sensitivity and favorable EPR characteristics for biological applications. At low pO2, the linewidth is particularly sensitive to changes in oxygen tension (sensitivity of 750 mG/mmHg). The application of the probes for oximetry was demonstrated in vivo: the pO2 was measured in muscle in which the blood flow was temporarily restricted as well as in tumor-bearing mice during a carbogen breathing challenge. The responsiveness to pO2 was stable in muscle for at least 3 months. No toxicity was observed using these materials in cellular experiments and in histological studies performed 2, 7, and 28 days after implantation. In view of their EPR characteristics (high sensitivity) as well as the well-characterized production procedure that make them available on a large scale, these probes can be considered as very promising tools for future developments in EPR oximetry. Magn Reson Med 51:1272-1278, 2004.

Low molecular weight nitroxides are widely used as electron paramagentic resonance(EPR)-detectable spin labels in the biological and pathological areas. A novel nitroxide derivative, 4-ferrocenecarboxyl-2,2,6,6-tetramethyl piperidine-1-oxyl(FC-TEMPO), was synthesized for evaluating the effects of spin label compounds on tumor cells and firstly its biological effects on tumor and normal cells were evaluated. The cytotoxicity of FC-TEMPO in the hige metastatic lung carcinoma cells(95-D) showed that it markedly inhibited the viabillity of cancer cells in a dose-dependent manner, while it was less toxic to a normal human cell line. Further studies found that FC-TEMPO suppressed the growth of tumor cells by induced apoptosis through activating caspase-3 but not caspase-8 which was proved by caspase inhibitors, and the cell cycle arrest at G; phase. Moreover, the concomitant increase of superoxide dismutase(SOD) and catalase (CAT) activity was boserved. Taken together, these resluts right provide a base for further anticancer investigations of nitroxides and their potential pharmacologicalapplications