Regenerative engineering represents a new multidisciplinary paradigm to engineer complex tissues, organs, or organ systems through the integration of tissue engineering with advanced materials science, stem cell science and developmental biology. While possessing elements of tissue engineering, regenerative medicine, and morphogenesis, regenerative engineering is distinct from these individual disciplines since it specifically focuses on the integration and subsequent response of stem cells to biomaterials. One goal of regenerative engineering is the design of materials capable of inducing associated cells toward highly specialized functions. For example, the interaction of cells with calcium phosphate surfaces has proven to be an important signaling modality in promoting osteogenic differentiation. A biodegradable polymer-ceramic composite system has been developed from poly(lactide-co-glycolide) and in situ synthesized hydroxyapatite based on the three-dimensional sintered microsphere matrix platform. We have systematically optimized scaffold physico-chemical, mechanical, and structural properties for bone tissue regeneration applications by varying several parameters such as solution pH, polymer:ceramic ratio, sintering time and sintering temperature. The bioactivity of composite scaffolds is attributed to their ability to deliver calcium ions to surrounding medium and allow for reprecipitation of calcium phosphate on the scaffold surface. Furthermore, the composite scaffolds have demonstrated increased loading capacity of osteoinductive growth factor (BMP-2) and a more sustained release profile due to a greater number of adsorption sites provided by the ionic calcium and phosphate groups as well as a larger matrix surface area. In vitro cell studies were performed to investigate the efficacy of this composite system to induce osteogenic differentiation of human adipose-derived stem cells. Cells cultured on the ceramic containing scaffolds exhibited significantly higher expression of osteoblastic markers and greater extracellular matrix mineralization than non-ceramic containing scaffolds, indicating the potential for the ceramic phase to promote osteogenic differentiation. In addition, loaded BMP-2 retained its bioactivity as a mitogen and osteoinductive agent during the differentiation of adipose-derived stem cells into mature osteoblasts. In vivo evaluation using a critical-sized ulnar defect model in New Zealand white rabbits demonstrated the ability of composite scaffolds to support cellular infiltration throughout the scaffold pore structure and vascularization of new tissue, as well as facilitate formation of newly mineralized bone tissue. The work described herein provides strong evidence for the potential of polymer-ceramic composite scaffolds to function as osteoinductive bone graft substitutes, and paves the way for future development of advanced tissue-inducing materials.

We present a new type of device to separate biochemical compounds wherein carbon nanotubes (CNTs) are integrated as chromatographic stationary phase. The CNTs were directly grown on the bottom of microfluidic channels on Si/SiO2 substrate by chemical vapor deposition (CVD). Acetylene was used as carbon source and Ni was employed as catalyst. For electrokinetic separations, higher electrical field strength is usually required; therefore, the CNTs were constructed in pillar-array-form by patterning Ni catalyst layer. Electrical field strength of 2.0 kV/cm has been realized, which is more than one order of magnitude higher than the one reported so far. The microfluidic chips integrated with CNTs were successfully used to separate a compound containing two Coumarin dyes, 240 mM C460 and 270 mM C480.

The purpose of this study is to develop new transparent conducting oxide (TCO) films by using combinatorial approach and to apply them for organic light emitting diodes (OLED) and/or thin film photovoltaic devices. For this, we have explored several TCO films with multi-components and optimized their properties by employing combinatorial sputtering system. For the first, we have fabricated combinatorial libraries composed Zn-In-Sn-O (ZITO) to reduce In content comparing with Sn-doped indium oxide (ITO). The ZITO films showed amorphous structure at the substrate temperature ranged RT∼ 350 °C, high transmittance over 85% at the visible range wavelength, and resistivity as low as 3x10-4∼10-3Ωcm. These results reveal that the ZITO films have indium composition as low as 30∼40% comparing with equivalent ITO films. Furthermore, we have fabricated OLED on glass substrates by using the amorphous ZITO anode. OLED fabricated on amorphous ZITO-coated glasses have exhibited good characteristics comparable to OLED on ITO films. Besides OLED, the amorphous ZITO TCO can be applied for other optoelectronic devices like electronic paper, thin film photovoltaic, and smart window.

Many metallic actinide systems host partially filled 5f electrons in the low-energy spectrum. Consequently, they exhibit diverse quantum mechanical phenomena such as magnetism, superconductivity, a mysterious hidden-order phase, or heavy-fermion behavior. Here we present results of a unified theoretical method based on the self-consistent GW formalism for the electronic many-body self-energy. We calculate the dynamic electronic correlation spectra starting from materials specific first-principles electronic band-structure. In particular, we present results for four isostructural intermetallic actinides PuCoIn5, PuCoGa5, PuRhGa5, and UCoGa5. A common underlying property of these materials is a strong spin–orbit coupling split band structure that enables substantial spin fluctuations. In a feedback effect on the electronic structure they create electronic ‘hot spots’, where the single-particle spectral weight is maximum, resulting in a universal peak-dip-hump feature. These results are in good agreement with experiments, suggesting that actinides are adequately described by the intermediate Coulomb interaction regime, where both itinerant (peak) and localized (hump) features coexist.

Combining Bisphophonates (BPs) and Calcium Phosphate Cement (CPC) to form a new medical device for the local treatment of Osteoporosis is a promising challenge. Our formulation was optimized from an apatitic-type CPC and we have shown that the best solution consists in introducing the bisphosphonate (Alendronate) in the calcium deficient apatite (CDA), a solid component of the cement, through a chemical exchange reaction. The cement obtained was characterized by 31 P NMR and high frequency impedance for monitoring the CPC setting. The presence of Alendronate in the cement was also demonstrated by 31 P NMR which has been also used to characterize the chemical transformation of α-TCP (main component of the apatitic cement) during the setting process. BP absorption/desorption experiments have been realized on cement blocks, under continuous flow condition, to model the release profile of the Alendronate. In vivo experiments showed promising results in terms of resorbability of the Alendronate–loaded cement while promoting new bone formation. The same methodology is considered to introduce gallium, a potential inhibitor of osteoclastic resorption, in a CPC formulation. First experiments have shown that gallium can be incorporated in calcium phosphate ceramics (i.e. β-TCP) where gallium is part of the network.

Proton exchange membrane with interconnected H+-transfer channels in submicron scale has been synthesized by means of pore filling polymerization. Polysulfone (PSU) membrane containing densely distributed pores is synthesized using the phase inversion approach. The membrane is then filled up with a designed formula consisting of monomers (e.g. 2-acrylamido-2-methylpropane sulphonic acid and N, N’-Methylenebisacrylamide) and a binary solvent. It is undertaken through solution diffusion of the monomer formula into the pores impregnated with the bore liquid. When the PSU matrix loaded with monomers is subjected to polymerization, a uniform distribution of interconnected H+-transfer channels is realized. This special membrane structure gives rise to a maximum ionic exchange capacity of 2.43 meq/g and the highest proton conductivity of 0.2 S/cm. Compared to the commercial Nafion® membrane, the pore-filled membrane significantly enhances the power output of H2-PEM fuel cell.

Inx Ga1-x N-based LED structures were grown on digital Alx Ga1-x N/GaN DBR substrate to enhance emission extraction. Same LED structure was grown on sapphire substrate as a comparison. LEDs grown on DBR substrate exhibited similar IV characteristics to that grown on sapphire substrate but emission-angle-dependent EL spectra were observed. Also, the resonant vertical cavity modes were observed in EL spectra of LEDs with DBR structure and compared to simulated results. Image processing analysis results show that light extraction of LEDs is enhanced with use of DBR substrate.

Alloy 22 has been extensively studied regarding its crevice corrosion (CC) resistance both in pure chloride solutions and in solutions containing different oxyanions that may act as inhibitors of crevice corrosion. The scope of this work was to study the general and localized corrosion behavior of Alloy 22 when phosphate ions were added to a 1 M NaCl solution at 90°C. Results from the electrochemical tests indicate that the size of the passive potential range and the localized corrosion repassivation potential value increased in the presence of phosphate ions. Results from creviced specimens showed a strong inhibition effect of phosphate ions on the chloride induced crevice corrosion of Alloy 22. The critical molar concentration ratio (RCRIT = [phosphate]/[Cl]) to inhibit crevice corrosion was 0.3.

Superconducting NMR pickup coils have to have a low surface resistance (Rs) under a high magnetic field. One way of reducing the Rs of superconducting thin films is adding artificial pins to the films. We examined the hetero-epitaxial growth of MgB2and YBCO thin films on decorated sapphire and MgO substrates while using nano-wires and nano-particles to add pins to the films.

We used ZnO nano-wire to add artificial grain boundary pins to MgB2 films. The tilted c-plane sapphire substrate with nano-step edges was used for these substrates. The terrace width with one lattice step edge can be controlled by changing the tilt angle. AFM images showed that the tilted c-plane sapphire substrate had straight nano-step edges. ZnO nono-wires were decorated on the nano-step edges by MOCVD, and then deposited on MgB2 films by sputtering. The Rs of the films was then measured with a sapphire rod resonator. The Rs of MgB2 thin films fabricated on the tilted c-plane sapphire substrate with ZnO nano-wires was lower than that of MgB2thin films on a conventional sapphire substrate under a high magnetic field.

We used BaZrO3(BZO) nano-particles to add the artificial pins to YBCO thin films. The BZO particles on the MgO substrates were fabricated by laser deposition. The size and density of these particles were controlled with a pulse number of laser shot. YBCO thin films were formed on decorated MgO substrate by laser deposition. The Rs of YBCO thin films on the decorated MgO substrate was lower than that of the YBCO films formed on a conventional MgO substrate under a high magnetic field.

We clarified that artificial pins in MgB2and YBCO thin films are useful for decreasing the Rs under a high magnetic field.

In the present paper, strain measurements based on second harmonic generation (SHG) and electron backscatter diffraction (EBSD) is demonstrated via two illustrative applications. While SHG gains access to strains in buried interfaces, EBSD can be used to measure strains in crystalline thin films with high spatial resolution on the order of tens of nanometers and high surface sensitivity. In addition, target preparation using low-voltage ion beam milling is demonstrated, gaining access to unstrained sample positions in strained silicon on insulator (sSOI) systems which are necessary for common “pattern-shift” methodologies.

Single-crystalline films of superconducting Sr1-x Kx Fe2As and Ba1-x Kx Fe2As2 were grown by molecular beam epitaxy (MBE). The most crucial problem in MBE growth of these compounds is the high volatility of elemental K. The key to incorporating K into films is low-temperature growth (≤ 350 ºC) in reduced As flux. We performed a systematic study of the doping dependence of T c in Ba1-x Kx Fe2As2 for x = 0.0 to 1.0. The highest T c on (T c end) so far attained for Ba1-x Kx Fe2As2 is 38.3 K (35.5 K) at x ~ 0.3.

In this study Ruthenium (II) tris (2, 2’-bipyridyl) complex in nonaqueous solution was studied by cyclic voltammetry and also its kinetic parameters were calculated. The redox reaction of ruthenium (II) trisbipyridyl complex is totally quasi-reversible and it can be described as a diffusion-controlled process. As a result of the redox reaction, the kinetic parameters of the electrode process such as diffusion coefficient (D), and heterogeneous rate constant (ks ) were calculated. In addition, the different thermodynamic parameters such as standard free energy (ΔG# ), enthalpy change (∆H# ), and entropy change (∆S# ) were determined and enthalpy change revealed the exothermic behavior of the electrode reaction. Both oxidation and reduction onset potentials of the ruthenium (II) trisbipyridyl complex was determined under the same experimental conditions to estimate the low ionization potential and electron affinity. The electrochemical and optical band gaps of the ruthenium (II) complex were compared.

A clear PL spectrum was observed from β-FeSi2 grains on gold (Au)-coated (100)Si substrates, and indicated the formation of crystal with the same high quality level as the β-FeSi2 on a copper (Cu)-coated Si substrate. Moreover, the temperature dependence of photoluminescence peak intensities showed lower density of the nonradiative recombination center in β-FeSi2 grains on Au-coated Si substrates than that of β-FeSi2 film on Cu-coated Si. Au was not detected in β-FeSi2 grains by STEM-EDX observation, while Cu was observed in the grains and grain boundaries of β-FeSi2 and rolled as non-radiative recombination center.

The photovoltaic characteristics of all polymer bulk heterojunction solar cells made of P3HT and a perylene diimide-based copolymer (PEK3) have been studied. Thermal annealing is needed to improve the performances. Annealing optimization induces an enhancement of the power conversion efficiency from 0.06 to 1%, Jsc from 0.24 to 2.9 mA/cm2 and FF from 0.32 to 0.59. The origin of such improvements has been investigated by studying the P3HT:PEK3 blend morphology, by means of absorption and emission spectroscopy and charge transport, from single carrier measurements on P3HT:PEK3 diodes. Upon annealing we have observed an increase in phase segregation and a 100-fold enhancement of the hole and electron mobilities, that favor the dissociation of bound electron-hole pairs and their transport to the electrodes. This explains the high FF of the annealed P3HT:PEK3 solar cell.

Resistive switches are being explored as a candidate for ultra-dense memory as well as logic circuits. The advantages of the resistive switches include high switching speed and excellent scaling potential. Here, we report for the first time the switching behavior of anti-parallel connected resistive switches (APS), which is a composite device exhibiting bi-directional switching properties. Under the opposite voltage biases, the two anti-parallel cells are alternatively set and reset, rendering the APS switched in both directions. For appropriate ON resistance values and set and reset voltages the two anti-parallel switches can be both set in conductive states. An APS device can be realized in a single switch by two coexisting Cu and oxygen vacancy nanofilaments which are formed and ruptured under opposite voltage polarities. The described APS behavior is of interest to logic applications and in neural networks.

Determining the redox conditions in the near field of deep underground radioactive waste disposal cells is a key question regarding the performance of metallic components (e.g. waste overpack), which may undergo drastic corrosion processes in oxic conditions. This oxic transient is supposed to be short due notably to the oxygen consumption by corrosion and pyrite oxidation. However, the observed precipitation of Fe(III)-minerals as well as localized corrosion patterns on steel coupons placed during 6 years in a borehole drilled in the Toarcian argillite of Tournemire (France) may suggest that in-situ oxic conditions lasted several years, which is not consistent with reactive transport simulations performed with usual hypotheses (perfect contact between materials, high pyrite accessibility, water saturated conditions). Multicomponent reactive transport simulations considering gas diffusion were performed with the code HYTEC and reproduce correctly the observations made in Tournemire while considering imperfect interfaces and resaturation processes. The model was then applied to a disposal cell for high-level waste (HLW) representative of the design developed in France, putting into evidence the possibility of a redox contrast between the front and back of a disposal cell in an argillaceous medium, as well as a duration of the oxic stage within the cell as long as the ventilation of handling drifts is maintained.

Metal/high-k dielectric core-shell nanocrystal (NC) memory capacitors were demonstrated by e-beam evaporation process. This kind of metal oxide semiconductor (MOS) memory shows good performance in charge storage, programming and erasing speeds. Compared to Co NC memory, Co/Al2O3 core-shell NC memory shows improved retention performance since the additional Al2O3 shell layer acts as a barrier, which prevent the leakage.

IV-VI semiconductor structures grown by molecular beam epitaxy (MBE) have been used to measure the cross-plane thermal conductivity of PbSe and PbSe/PbSnSe/PbSe multiperiod superlattice (SL) materials. Continuous wave photoluminescence (PL) measurements were used to determine epilayer temperatures localized to multiple quantum well (MQW) light emitting layers on top of various IV-VI materials structures. These data combined with finite element analysis (FEA) were used to extract cross-plane thermal conductivity values for different materials designs. Structures consisting of PbSe/PbSnSe/PbSe SL materials with multiple periodicities exhibited cross-plane lattice thermal conductivity values as low as 0.30 W/mK, a significant reduction relative to the 1.9 W/mK value for bulk PbSe. This work shows that lattice thermal conductivity reduction offers a highly viable approach for improving thermoelectric materials performance.

Colloidal sol-gel is a common method used for the preparation of stable and homogeneous nanoparticulate sols. In this work, TiO2 and Er3+ doped-TiO2 sols (1, 2 and 3 mole % Er3+) have been prepared. The peptization time, viscosity and isoelectric point increase at higher Er3+ concentration indicating that erbium (III) delays the peptization process, increases the viscosity and adsorbs onto the surface of the TiO2 nanoparticles. When the sols of TiO2 are doped with Er3+ lower values of the band gap are obtained. After drying, in all cases, anatase was obtained as major phase although traces of brookite are also detected. The microstructure was observed by TEM and shows direct evidence that the xerogels are polycrystalline.