Evaluating Osteogenic Potential of Ligamentum Flavum Cells Cultivated in Photoresponsive Hydrogel that Incorporates Bone Morphogenetic Protein-2 for Spinal Fusion

Regenerative medicine is increasingly important in clinical practice. Ligamentum flava (LF) are typically removed during spine-related surgeries. LF may be a source of cells for spinal fusion that is conducted using tissue engineering techniques. In this investigation, LF cells of rabbits were isolated and then characterized by flow cytometry, morphological observation, and immunofluorescence staining. The LF cells were also cultivated in polyethylene (glycol) diacrylate (PEGDA) hydrogels that incorporated bone morphogenetic protein-2 (BMP-2) growth factor, to evaluate their proliferation and secretion of ECM and differentiation in vitro. The experimental results thus obtained that the proliferation, ECM secretion, and differentiation of the PEGDA-BMP-2 group exceeded those of the PEGDA group during the period of cultivation. The mineralization and histological staining results differed similarly. A nude mice model was utilized to prove that LF cells on hydrogels could undergo osteogenic differentiation in vivo. These experimental results also revealed that the PEGDA-BMP-2 group had better osteogenic effects than the PEGDA group following a 12 weeks after transplantation. According to all of these experimental results, LF cells are a source of cells for spinal fusion and PEGDA-BMP-2 hydrogel is a candidate biomaterial for spinal fusion by tissue engineering.     

Rapid optimization of blast wave mitigation strategies using Quiet Direct Simulation and Genetic Algorithm

Presented is a rapid calculation tool for the optimization of blast wave related mitigation strategies. The motion of gas resulting from a blast wave (specified by the user) is solved by the Quiet Direct Simulation (QDS) method - a rapid kinetic theory-based finite volume method. The optimization routine employed is a newly developed Genetic Algorithm (GA) which is demonstrated to be similar to a Differential Evolution (DE) scheme with several modifications. In any Genetic Algorithm, individuals contain genetic information which is passed on to newly created individuals in successive generations. The results from unsteady QDS simulations are used to determine the individual's “genetic fitness” which is employed by the proposed Genetic Algorithm during the reproduction process. The combined QDS/GA algorithm is applied to various test cases and finally the optimization of a non-trivial blast wave mitigation strategy. Both QDS and the proposed GA are demonstrated to perform with minimal computational expense while accurately solving the optimization problems presented.     

Evaluation of carbon monoxide oxidation over CeO2/Co3O4 catalysts: Effect of ceria loading

Modification of cobaltic oxide (obtained from the reduction of high-valence cobalt oxide and assigned as R230, S_BET = 100 m² g⁻¹) with different loading of ceria was proceeded using the impregnation method (assigned as CeX/R230, X = 4, 12, 20, 35 and 50 wt%). The CeX/R230 catalysts were characterized by X-ray diffraction (XRD), nitrogen adsorption at −196 °C, temperature-programmed reduction (TPR) and transmission electron microscopy (TEM). Their catalytic activities towards the CO oxidation were studied in a continuous flow micro-reactor. The results revealed that the optimal modification, i.e., Ce20/R230, can increase the surface area (S_BET = 109 m² g⁻¹) of cobaltic oxide, further weaken the bond strength of CoO and lower the activation of CO oxidation among CeX/R230 catalysts due to the combined effect of cobaltic oxide and ceria. The Ce20/R230 catalyst exhibited the best catalytic activity in CO oxidation with T₅₀ (temperature for 50% CO conversion) at 88 °C.     

Efficient inverted solar cells using TiO(2) nanotube arrays

Using a vertical titania (TiO(2)) nanotube array, an inverted polymer solar cell was constructed with power conversion efficiency up to 2.71%. In this study, self-organized TiO(2) nanotubes arrays were grown by anodizing Ti metal in glycerol electrolyte containing 0.5?wt% NH(4)F and 1.0?wt% H(2)O with 20?V potential. The tube length (～100?nm) was controlled by the thickness of the sputtered titanium layer on the indium-tin oxide (ITO) substrate. The diameter of the tube was approximately 15-25?nm. After annealing in air at 500?°C for 1?h, nanotubes arrays were crystallized to the anatase phase from the initial amorphous state. Following the infiltration of polymeric semiconductor (poly(3-hexylthiophene) and (6,6)-phenyl C(60) butyric acid methyl ester, P3HT:PCBM), the filled TiO(2) layer had an optical absorption over a range from UV to visible light. The high surface-to-volume ratio of the nanotube arrays structure increased the effective area of the active region. The high efficiency of our solar cell is attributed to the vertical TiO(2) nanotube array's enhanced conduction of photo-induced current due to its charge transport capability.     

Iridium-complex-functionalized Fe3O4/SiO2 core/shell nanoparticles: a facile three-in-one system in magnetic resonance imaging, luminescence imaging, and photodynamic therapy

Highly uniform Fe3O4/SiO2 core/shell nanoparticles functionalized by phosphorescent iridium complexes (Ir) have been strategically designed and synthesized. The Fe3O4/SiO2(Ir) nanocomposite demonstrates its versatility in various applications: the magnetic core provides the capability for magnetic resonance imaging and the great enhancement of the spin-orbit coupling in the iridium complex makes it well suited for phosphorescent labeling and simultaneous singlet oxygen generation to induce apoptosis.     

Type-II CdSe/CdTe/ZnTe (core-shell-shell) quantum dots with cascade band edges: the separation of electron (at CdSe) and hole (at ZnTe) by the CdTe layer

The rational design and synthesis of CdSe/CdTe/ZnTe (core-shell-shell) type-II quantum dots are reported. Their photophysical properties are investigated via the interband CdSe-->ZnTe emission and its associated relaxation dynamics. In comparison to the strong CdSe (core only) emission (lambda(max) approximately 550 nm, Phi(f) approximately 0.28), a moderate CdSe-->CdTe emission (lambda(max) approximately 1026 nm, Phi(f) approximately 1.2 x 10(-3)) and rather weak CdSe-->ZnTe interband emission (lambda(max) approximately 1415 nm, Phi(f) approximately 1.1 x 10(-5)) are resolved for the CdSe/CdTe/ZnTe structure (3.4/1.8/1.3 nm). Capping CdSe/CdTe with ZnTe results in a distant electron-hole separation between CdSe (electron) and ZnTe (hole) via an intermediate CdTe layer. In the case of the CdSe/CdTe/ZnTe structure, a lifetime as long as 150 ns is observed for the CdSe-->ZnTe (1415 nm) emission. This result further indicates an enormously long radiative lifetime of approximately 10 ms. Upon excitation of the CdSe/CdTe/ZnTe structure, the long-lived charge separation may further serve as an excellent hole carrier for catalyzing the redox oxidation reaction.     

Max-Life Power Schedule for Connectivity and Biconnectivity in Wireless Ad Hoc Networks

Given the initial energy supplies and the maximal transmission power of the individual nodes in a wireless ad hoc network, a power schedule of duration t for a specified topological property is a scheduling of the transmission powers of the individual nodes over the period [0, t] such that (1) the total amount of energy consumed by each node during the period [0, t] does not exceed its initial energy supply, (2) the transmission power of each node at any moment in the period [0, t] does not exceed its maximal transmission power, and (3) the produced network topology at any moment in the period [0, t] satisfies the property . The problem Max-Life Power Schedule for seeks a power schedule of the maximal duration for . Let g be the golden ratio , and ε be an arbitrarily positive constant less than one. In this paper, we present a -approximation algorithm for Max-Life Power Schedule for Connectivity, a -approximation algorithm for Max-Life Power Schedule for 2-Node-Connectivity, and a -approximation algorithm for Max-Life Power Schedule for 2-Edge-Connectivity. This work is supported in part by Research Grants Council of Hong Kong under grant number CityU 9041040. Peng-Jun Wan received his Ph.D. degree from University of Minnesota, MS degree from The Chinese Academy of Science, and BS degree from Tsinghua University. He is currently an Associate Professor in Computer Science at Illinois Institute of Technology, and at City University of Hong Kong. His research interests include wireless networks, optical networks, and algorithm design and analysis. Chih-Wei Yi received his M.S. and B.S. degrees from National Taiwan University. He is currently a Ph.D. candidate at the Illinois Institute of Technology. His dissertational research focuses on wireless ad hoc networks. He is expected to graduate in 2005.     

In situ FT-IR Spectroscopic Studies on the Mechanism of the Catalytic Oxidation of Carbon Monoxide over Supported Cobalt Catalysts

Three types of supported cobalt catalysts (5% as metal Co loading on SiO₂, Al₂O₃ and TiO₂) were prepared by incipient wetness impregnation with aqueous Co(NO₃)₂·6H₂O solution. Then, all catalysts were calcined in air at 400 °C (assigned as 5Co/Si C400, 5Co/Al C400 and 5Co/Ti C400). Their catalytic activities towards the CO oxidation were studied in a continuous flow micro-reactor. Adsorption of carbon monoxide (CO) and the co-adsorption of CO/O₂ over cobalt oxide were further tested under in situ FT-IR. The results showed that both 5Co/Si C400 and 5Co/Al C400 had higher activity than 5Co/Ti C400. The T₅₀ (50% conversion) for both 5Co/Si C400 and 5Co/Al C400 was reached at temperatures as low as ambient temperature. According to the in situ FT-IR analysis, the variation in oxidation of CO was interpreted with different mechanisms, i.e., the reaction between adsorbed CO and lattice oxygen of cobalt oxide, and part of CO₂ formation via carbonates on 5Co/Si C400; both types of carbonates are formed on 5Co/Al C400 to promote the CO oxidation; while both strong adsorption of CO on TiO₂ and CO₂ on cobalt oxide for 5Co/Ti C400 leads to affect the activity.     

Integrating case-based and fuzzy reasoning to qualitatively predict risk in an environmental impact assessment review

During the preparation of environmental impact statements (EIS) and environmental impact assessment reports (EIAR) for a development proposal, developers have three concerns. First is acquiring similar proposals for reference. Second is to forecast a possible review result for a compiled EIS or EIAR: approval, conditional approval, second-stage EIA, or disapproval. Risk management in accordance with the possible review result is the third issue. With the predicted possible review result, early preparation and revision of environmental management plans can ameliorate in advance highly risky nuisances; thereby the probability of passing review is relatively enhanced. In response to the first concern, Taiwan EPA provides developers an information system to access EISs and EIARs through the Internet. Except that, there is no related system to address these concerns in Taiwan. In this paper, the following suggestions of using artificial intelligence and management science are proposed to assist developers: case-based reasoning (CBR) for retrieval of similar cases, fuzzy reasoning (FR) for qualitative risk forecast, and importance–performance analysis (IPA) for risk management. Finally, a case study is used to demonstrate the use of the proposed system.     

Structure-specified IIR filter and control design using real structured genetic algorithm

This paper develops an innovative optimization method, real structured genetic algorithm (RSGA), which combines the advantages of traditional real genetic algorithm (RGA) with structured genetic algorithm (SGA), and applies it for digital filter and control design optimization problems. For infinite impulse response (IIR) filter designs, the proposed approach fulfills all types of filters by minimizing the order of the filter and the absolute error of both passband and stopband. Both system structure and parametric variables are simultaneously optimized via the proposed chromosome scheme. The approach has also been extended to deal with robust control design problems. The approach offers an effective method for designing an optimal controller with robust stability. Simulation and experimental results conveys the excellence of the proposed algorithm over traditional approaches in convergence speed, performance, cost effectiveness, and attains simpler structure.