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Chen H.-L.,Chinese Culture University | Su C.-H.,Institute for Translational Research in Biomedicine | Ju S.-P.,National Sun Yat - sen University | Ju S.-P.,Kaohsiung Medical University | And 2 more authors.
RSC Advances | Year: 2015

The mechanical and thermal properties of Fe54C18Cr16Mo12 bulk metallic glasses (BMGs) were investigated by a molecular dynamics simulation with the 2NN modified embedded-atom method (MEAM) potential. The fitting process of the cross-element parameters of 2NN MEAM (Fe-C, Fe-Cr, Fe-Mo, C-Cr, C-Mo, and Cr-Mo) was carried out first by the force matching method (FMM) on the basis of the reference data from density functional theory (DFT) calculations. With these fitted parameters, the structure of Fe54C18Cr16Mo12 BMG was constructed by the simulated-annealing basin-hopping (SABH) method, and the angle distribution range of the X-ray diffraction profile of the predicted Fe54C18Cr16Mo12 BMG closely matches that of the experiment profile, indicating the fitted 2NN MEAM parameters can accurately reflect the interatomic interactions of Fe54C18Cr16Mo12 BMG. The Honeycutt-Andersen (HA) index analysis results show a significant percentage of icosahedral-like structures within Fe54C18Cr16Mo12 BMG, which suggests an amorphous state. According to the tensile test results, the estimated Young's modulus of Fe54Cr16Mo12C18 bulk metallic glass is about 139 GPa and the large plastic region of the stress-strain curve shows that the Fe54C18Cr16Mo12 BMG possesses good ductility. Local strain distribution was used to analyze the deformation mechanism, and the results show that a shear band develops homogeneously with the tensile fracture angle (T) at about 50 degrees, in agreement with experimental results 45° < T < 90°. For the temperature elevation results, the discontinuity of the enthalpy-temperature profile indicates the melting point of Fe54Cr16Mo12C18 BMG is about 1310 K. The diffusion coefficients near the melting point were derived by the Einstein equation from the mean-square-displacement (MSD) profiles between 800-1400 K. On the basis of diffusion coefficients at different temperatures, the diffusion barriers of Fe54Cr16Mo12C18 can be determined by the Arrhenius equation. The diffusion barriers of total for Fe, Cr, Mo, C are 31.88, 24.68, 35.26, 22.50 and 31.79 kJ mol-1, respectively. The diffusion barriers of Fe and Cr atoms are relatively lower, indicating Fe and Cr atoms more easily diffuse with the increasing temperature. © The Royal Society of Chemistry 2015. Source


Hsiao M.-K.,Chinese Culture University | Su C.-H.,Institute for Translational Research in Biomedicine | Liu C.-Y.,Chinese Culture University | Chen H.-L.,Chinese Culture University
Physical Chemistry Chemical Physics | Year: 2015

Hydrogen gas will play an important role in the future since it could be a replacement for gasoline, heating oil, natural gas, and other fuels. In previous reports ammonia (NH3), which has a high hydrogen content, provides a promising mode for the transferring and storing of hydrogen for its on-site generation. Therefore, the dehydrogenation of NH3 on a metal surface has been studied widely in the last few decades. In our study, we employed monolayer tungsten metal to modify the Fe(111) surface, denoted as W@Fe(111), and calculated the adsorption and dehydrogenation behaviors of NH3 on W@Fe(111) surface via first-principles calculations based on density functional theory (DFT). The three adsorption sites of the surface, top (T), 3-fold-shallow (S), and 3-fold-deep (D) were considered. The most stable structure of the NHx (x = 0-3) species on the surface of W@Fe(111) have been predicted. The calculated activation energies for NHx (x = 1-3) dehydrogenations are 19.29 kcal mol-1 (for H2N-H bond activation), 29.17 kcal mol-1 (for HN-H bond activation) and 27.94 kcal mol-1 (for N-H bond activation), and the entire process is exothermic by 33.05 kcal mol-1. To gain detailed knowledge of the catalytic processes of the NH3 molecule on the W@Fe(111) surface, the physical insights between the adsorbate/substrate interaction and interface morphology were subjected to a detailed electronic analysis. © the Owner Societies. Source


Su C.-H.,Institute for Translational Research in Biomedicine | Su C.-H.,National Yang Ming University | Cheng F.-Y.,National Cheng Kung University
RSC Advances | Year: 2015

Nanocomposites composed of highly biocompatible and safe alginate and iron oxide nanoparticles have been employed to encapsulate doxorubicine for brain tumor therapy. The antitumor activity of nanocomposites was demonstrated using in vitro and in vivo tests. The results significantly indicated that the nanocomposites had great safety and potential for brain tumor therapy. © The Royal Society of Chemistry. Source


Huang Y.-K.,National Cheng Kung University | Su C.-H.,Institute for Translational Research in Biomedicine | Chen J.-J.,National Cheng Kung University | Chang C.-T.,National Cheng Kung University | And 4 more authors.
ACS Applied Materials and Interfaces | Year: 2016

Iron oxide nanoparticles (IONPs)-carbon (C) hybrid zero-dimensional nanostructures normally can be categorized into core-shell and yolk-shell architectures. Although IONP-C is a promising theranostic nanoagent, the in vivo study has surprisingly been less described. In addition, little effort has strived toward the fabrication of yolk-shell compared to the core-shell structures. In this context, we synthesized a yolk-shell type of the silica-coated hollow carbon nanospheres encapsulating IONPs cluster, which can be dispersed in aqueous solution for systemic studies in vivo, via the preparation involving the mixed micellization, polymerization/hollowing, sol-gel (hydration-condensation), and pyrolysis processes. Through a surface modification of the polyethylenimine followed by the sol-gel process, the silica shell coating was able to escape from condensing and sintering courses resulting in aggregation, due to the annealing. Not limited to the well-known functionalities in magnetical targeting and magnetic resonance (MR) imaging for IONP-C hybrid structures, we expanded this yolk-shell NPs as a near-infrared (NIR) light-responsive echogenic nanoagent giving an enhanced ultrasound imaging. Overall, we fabricated the NIR sensitive yolk-shell IONP-C to activate ultrasound imaging and photothermal ablation under magnetically and MR imaging guided therapy. © 2016 American Chemical Society. Source


Luo C.-H.,National Cheng Kung University | Huang C.-T.,National Cheng Kung University | Su C.-H.,Institute for Translational Research in Biomedicine | Yeh C.-S.,National Cheng Kung University
Nano Letters | Year: 2016

The hypoxia region in a solid tumor has been recognized as a complex microenvironment revealing very low oxygen concentration and deficient nutrients. The hypoxic environment reduces the susceptibility of the cancer cells to anticancer drugs, low response of free radicals, and less proliferation of cancer cells in the center of the solid tumors. However, the reduced oxygen surroundings provide an appreciable habitat for anaerobic bacteria to colonize. Here, we present the bacteria-mediated targeting hypoxia to offer the expandable spectra for diagnosis and therapy in cancer diseases. Two delivery approaches involving a cargo-carrying method and an antibody-directed method were designed to deliver upconversion nanorods for imaging and Au nanorods for photothermal ablation upon near-infrared light excitation for two forms of the anaerobic Bifidobacterium breve and Clostridium difficile. The antibody-directed strategy shows the most effective treatment giving stronger imaging and longer retention period and effective therapy to completely remove tumors. © 2016 American Chemical Society. Source

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