Biomedical subjects
Publications and source records attributed to Ching-Yao Lin.
UV-visible absorption and AFM studies suggest that carboxyphenylethynyl zinc porphyrins aggregate on nanocrystalline TiO2 surfaces in an H-type fashion.
The excited-state relaxation dynamics of a synthetic porphyrin, ZnCAPEBPP, in solution, coated on a glass substrate as solid films, mixed with PMMA and coated on a glass substrate as solid films, and sensitized on nanocrystalline TiO2 films were investigated by using femtosecond fluorescence up-conversion spectroscopy with excitation in the Soret band, S2. We found that the S2--> S1 electronic relaxation of ZnCAPEBPP in solution and on PMMA films occurs in 910 and 690 fs, respectively, but it becomes extremely rapid, <100 fs, in solid films and TiO2 films due to formation of porphyrin aggregates. When probed in the S1 state of porphyrin, the fluorescence transients of the solid films show a biphasic kinetic feature with the rapid and slow components decaying in 1.9-2.4 and 19-26 ps, respectively. The transients in ZnCAPEBPP/TiO2 films also feature two relaxation processes but they occur on different time scales, 100-300 fs and 0.8-4.1 ps, and contain a small offset. According to the variation of relaxation period as a function of molecular density on a TiO2 surface, we assigned the femtosecond component of the TiO2 films as due to indirect interfacial electron transfer through a phenylethynyl bridge attached to one of four meso positions of the porphyrin ring, and the picosecond component arising from intermolecular energy transfer among porphyrins. The observed variation of aggregate-induced relaxation periods between solid and TiO2 films is due mainly to aggregation of two types: J-type aggregation is dominant in the former case whereas H-type aggregation prevails in the latter case.
The goal of our project is to build a system which could utilize the Virtual Reality (VR) techniques for the pre-operative planning of craniosynostosis. The system includes different modules. We use the tetrahedral volume meshes for the basic structure for the models which surgery is planning on. This paper will describe the procedures of above stages, from the processing of 2D image slices, 3D modeling, smoothing, simplification, and visibility ordering, to volume meshes generation. We have demonstrated the initial results on a variety of stereo devices. The testing results show the processing time is acceptable and the rendering effect is pretty well.
Free-base, nickel(II), zinc(II) and iron(III) mono(4-aniline-ethynyl)biphenylporphines (AEBPPs) were synthesized and their electro-polymerization reactions were studied. Electrochemical and UV-Visible experiments showed that AEBPPs were electro-polymerized onto Pt and indium tin oxide (ITO) surfaces without significantly changing their redox and spectral properties. This suggests that the pi-conjugations of these porphyrins were not greatly affected upon electro-polymerization. SEM images indicated the formation of porphyrin films on the electrode surfaces, while EDS spectra of the metallo-AEBPP films confirmed deposits of the corresponding metals. Upon closer inspection, the AFM images revealed nano-scale fine structure of these porphyrin films. Both SEM and AFM images of the porphyrin films showed similar trends of porphyrin accumulation.
A series of nickel N-methyl-pyridylethynylporphines were synthesized and their electrochemical and absorption properties were studied. UV-visible spectra of these complexes show that the absorption red-shifts of the nickel porphyrins are as significant as the zinc analogues. Although the reduction potential shifts caused by the electron-withdrawing substituents are not as large as the zinc complexes, the first reduction potentials of the nickel porphyrins are more positive than those of the zinc counterparts. In addition, the redox behaviors of these nickel porphyrins are similar to those of the zinc analogues.
A new series of electron-deficient porphyrins were prepared by attaching one or two N-methylated 2-, 3- or 4-pyridylethynyl groups to the 10,20-meso positions of (5,15-biphenylporphinato)zinc(II). Electrochemical studies showed significant changes in the reduction potentials of these porphyrins, and N-methyl-2-pyridylethyne is the strongest electron-withdrawing substituent in the series. UV-visible spectra demonstrated largely red-shifted absorptions, and N-methyl-4-pyridylethyne has the greatest impact to the porphyrin absorptions. Electrochemical, UV-visible and EPR results concluded that porphyrins Zn2 and Zn6 reversibly undergo two one-electron porphyrin-ring reductions to their anion radicals then dianions. The first reductions of porphyrins Zn1, Zn3, Zn4 and Zn5 were irreversible one-electron transfer processes. The instability of these reduction products was suggested to result from the eletrophilic attacks at the substituents.
The mortality associated with undrained intra-abdominal abscesses is high. Computed tomography-guided percutaneous drainage (CT-PD), a minimally invasive technique, allows a drainage catheter to be inserted into fluid collections throughout the body with minimal risk. We described two neutropenic patients with intra-abdominal abscesses treated with CT-PD after they failed to respond to antimicrobial therapy. With this modality, the surgery was successfully avoided or delayed. We are of an opinion that CT-PD is an efficient and simple urgent radiology procedure.