Yi-Ru Li’s research while affiliated with Academia Sinica and other places

Data Missing is a common issue in traffic data processing. This study proposes pretime interpolation and realtime extrapolation for missed data compensation. Herein, cubic spline curve interpolation, linear interpolation, and near value method are applied for pretime operation. Mean value method, Fourier transform method, α-β-γ filter with mean value and α-β-γ filter with Fourier transform method are involved for realtime operation. According to the experiments, the practices result the linear interpolation is shown of the best way for pretime works. About realtime extrapolation, the proposed four methods present without significant difference. The paper finally conducts travel time prediction via the compensated database revealing good performance.

Vascular smooth muscle cell (VSMC) migration play a key role in the development of intimal hyperplasia and atherosclerosis. Galectin-1 (Gal-1) is a redox-sensitive β-galactoside-binding lectin expressed in VSMCs with intracellular and extracellular localizations. Here we show that VSMCs deficient in Gal-1 (Gal-1-KO) exhibited greater motility than wild type (WT) cells. Likewise, Gal-1-KO-VSMC migration was inhibited by a redox-insensitive but activity-preserved Gal-1 (CSGal-1) in a glycan-dependent manner. Gal-1-KO-VSMCs adhered slower than WT cells on fibronectin. Cell spreading and focal adhesion (FA) formation examined by phalloidin and vinculin staining were less in Gal-1-KO-VSMCs. Concomitantly, FA kinase (FAK) phosphorylation was induced to a lower extent in Gal-1-KO cells. Analysis of FA dynamics by nocodazole washout assay demonstrated that FA disassembly, correlated with FAK de-phosphorylation, was faster in Gal-1-KO-VSMCs. Surface plasmon resonance assay demonstrated that CSGal-1 interacted with α5β1integrin and fibronectin in a glycan-dependent manner. Chemical crosslinking experiment and atomic force microscopy further revealed the involvement of extracellular Gal-1 in strengthening VSMC-fibronectin interaction. In vivo experiment showed that carotid ligation-induced neointimal hyperplasia was more severe in Gal-1-KO mice than WT counterparts. Collectively, these data disclose that Gal-1 restricts VSMC migration by modulating cell-matrix interaction and focal adhesion turnover, which limits neointimal formation post vascular injury.

We developed dielectric heating-assisted nanoimprint method for rapid fabrication of ultraflexible nanostructures. Using spin-coating polyvinyl-chloride (PVC) film on the glass slide, the dielectric heating on PVC film helped the pattern transfer from the mold to PVC film in few seconds. Various kinds of nanostructures were successfully made on PVC films with about 20-μm thickness. We demonstrated the applications of ultraflexible metallic nanostructures for bending measurement using surface plasmon resonance (SPR) and surface enhanced Raman scattering (SERS) on the curved surfaces. For measuring bending angles using SPR on capped nanowire arrays, the minimum detection angle was 2.4 × 10⁻³ degree under 0.02 nm wavelength resolution. For SERS measurement, the nanorod arrays on a curved substrate can increase SERS signals for two times as compared to planar SERS substrate.

We present an electrostatic-field-tunable ferroelectric template to produce photoreduced silver nanostructures for Raman scattering enhancement. The intensity and distribution of the surface electrostatic field in the ferroelectric template determine the morphology of the photoreduced silver nanostructures and thus the degree of the Raman signal enhancement. The surface electrostatic field is produced by periodically proton-exchanged (PPE) regions in LiNbO3 and is tuned by thermal annealing to obtain the favorable photoreduced silver nanostructure. The variation of surface electrostatic properties by thermal annealing is simulated using the finite element method and measured by electrostatic force microscopy. The mechanism of silver nanostructure formation affected by the electrostatic field distribution is discussed. The formed silver nanostructures are functionalized by R6G dye to enable Raman signal measurement. The proposed method is demonstrated to be effective in tuning the surface electrostatic field distribution and produces a 4.13 times higher silver nanostructure and a 2.51 times larger Raman intensity in comparison with the conventional PPE sample.