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Nanostructures have been widely employed to reduce optical refkection for various optoelectronic devices. In this work, the aligned nanostructure arrays of with desirable diameter and density were obtained. We demonstrated the potential applications of nanosphere lithography in fabrication of Si nanoholes (SiNHs) and Si nanowires (SiNWs) with excellent broadband light antirefkectance properties. Both nanostructures drastically suppress the refkection across the whole measured spectrum with wavelength above Si band gap (1.12 eV) as compared to that of planar Si wafer. The refkectance intensity of SiNHs and SiNWs is less than 6% over broad range of 400 to 1000 nm. The nanosphere lithography technique is expected to have potential applications in fabrication of nanostructures with various properties.

Lamellar nanomaterials with specific architectures and novel properties have received increasing attention from both scientific and technological fields in recent years because of their potential applications in catalysis, energy conversion, and storage devices. Bulk supercluster pellets with well-defined lamellar structures were fabricated by assembling silver clusters and mercaptoalkyl acids (MXA) to investigate the mechanical properties. The relationship between the assembled structure and pressure resistance was surveyed for the first time. The enhanced interlayer interactions were found to increase the elastic modulus of the Ag-MXA supercluster architectures.

Clustering analysis is an important method of multivariate statistical analysis. It has important applications in pattern recognition, artificial intelligence, automatic control and other fields. An iterative algorithm called uncertain means clustering is defined by analyzing the contribution of the features to the sample and calculating the degree of membership based on the weight. In this paper, we use the uncertain means clustering algorithm to cluster IRIS data to test the clustering accuracy, convergence speed and robustness of the algorithm. At the same time, compared with the traditional clustering algorithm, which K-Means clustering algorithm and KNN clustering algorithm, the experimental results show that the uncertain means clustering algorithm has good performance in the accuracy and convergence speed of the sample data sets, and is an effective unsupervised clustering algorithm.

Pressure evolution of local structure and vibrational dynamics of the perovskite-type relaxor ferroelectric single crystal of 0.935(Na0.5Bi0.5)TiO3-0.065BaTiO3 (NBT-6.5BT) is systematically investigated via in situ Raman spectroscopy. The pressure dependence of phonon modes up to 30 GPa reveals two characteristic pressures: one is at around 4.6 GPa which corresponds to the rhombohedral-to-tetragonal phase transition, showing that the pressure strongly suppresses the coupling between the off-centered A- and B-site cations; the other structural transition involving the oxygen octahedral tilt and vibration occurs at pressure ∼13–15 GPa with certain degree of order-disorder transition, evidenced by the abnormal changes of intensity and FWHM in Raman spectrum.

Highly (111) preferred oriented PbZr 0.53 Ti 0.47 O 3 /Pb(Mg 1/3 Nb 2/3 ) 0.62 Ti 0.38 O 3 /PbZr 0.53 Ti 0.47 O 3 (PZT/PMNT/PZT) trilayered ferroelectric thin films were prepared on (111)Pt/Ti/SiO 2 /Si substrates. At room temperature, the films have a dielectric constant of 2175 that decreases to 1870 and a dielectric loss of 0.05 that increases to 0.06 with increasing frequency between 10 2 and 10 5 Hz. Also, they exhibit well saturated polarization-versus-electric field hysteresis loops with a large remnant polarization of 13.4 μC/cm 2 and a low coercive field of 30 kV/cm. The leakage current density in the trilayered films is 4.1 × 10 −10 A/cm 2 , which increases to 4.0 × 10 −7 A/cm 2 with increasing electric field between 1 and 140 kV/cm. Such properties of (111) preferred oriented PZT/PMNT/PZT trilayered films lead naturally to possibilities for ferroelectric capacitors and memories.

The adsorption capacity of existing β-CD-based adsorbents is generally restrained by the limited dimension of β-CD's inherent cavity. To find an effective way to expand the inclusion/adsorption capacity of β-CD, a series of N-containing groups, amine with straight chain, imidazole with rigid five-membered ring and pyridine with rigid six-membered ring, are firstly utilized to alkylate the secondary rim of β-CD through the thiol-Michael addition. The capsulation ability of the resultant β-CD derivatives are compared and the β-CD derivatives appended with aromatic imidazole or pyridine provide extremely rich host surroundings for loading Rhodamine B (RB), which is identified by the 1H NMR titration and UV–Vis spectroscopy. The bi-functional adsorbents correlative to those β-CD derivatives are then synthesized by the polymerization of vinylated β-CD and the corresponding vinyl N-containing monomers, and applied to remove RB and Cd (II) from the aqueous condition. Governed by multiple factors such as porosity, surface charge and binding affinity, the imidazole modified β-CD adsorbent revealed the best adsorption efficiency for organic dyes and metal ions, in both single- and bi-component solutions. Our work provides effective strategy and reliable basis for the design and fabrication of β-CD-based materials with high capacity and multi-functionality.

The fundamental physical properties including density, viscosity, refractive index and relative permittivity, have been measured for binary mixtures of exo-tetrahydrodicyclopentadiene (JP-10) with four octane isomers (n-octane, 3-methylheptane, 2,4-dimethylhexane and 2,2,4-trimethylpentane) over the whole composition range at temperatures T = (293.15 to 313.15) K and pressure p = 0.1 MPa. The values of excess molar volume V m E , viscosity deviation (Δη), refractive index deviation (ΔnD) and relative permittivity deviation (Δer) are then calculated. All of the values of V m E and Δη are observed to be negative, while those of ΔnD and Δer are close to zero. The effects of temperature and composition on the variation of V m E values are discussed. The negative values of V m E and Δη are conductive to high-density and low-resistance of fuels, which is favorable for the design and preparation of advanced hydrocarbon fuels.

For a comprehensive understanding of the properties of 1,3-dimethyladamantane (1,3-DMA) as a candidate of high energy-density hydrocarbon fuels, thermal stability of 1,3-DMA under different conditions is investigated. The thermal decomposition kinetics in the batch reactor between 693 and 743 K has been determined, with the rate constants ranging from 4.00 × 10–7 s–1 at 693 K to 35.19 × 10–7 s–1 at 743 K, along with the Arrhenius parameters of A = 2.39 × 107 s–1 and activation energy Ea = 183 kJ·mol–1. The rate constants for the thermal decomposition of 1,3-DMA are observed to be smaller than those of some typical model fuels, decalin, propylcyclohexane, butylcylohexane, and n-dodecane, demonstrating that the thermal stability of 1,3-DMA is satisfactory. The thermal decomposition of 1,3-DMA in the flowing reactor at temperatures from 873 to 973 K and pressures from 0.1 to 5.0 MPa is further performed. It can be observed that the conversion of 1,3-DMA and the yield of gaseous products increase clearly with...

Hydrogenated amorphous silicon carbide (a-SiCx:H) thin films were deposited using a radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) system with methane (CH4) and silane (SiH4) as reactive precursor gases and H2 as a carrier and dilution gas. The effects of RF-PECVD deposition conditions on the optical properties and microstructural characteristics of a-SiCx:H thin films were systematically investigated. When the RF power density, deposition pressure (P) and temperature (Ts) were fixed, the refractive index (n) and the growth rate of a-SiCx:H thin films decreased with the CH4/SiH4 flow rate ratio (R), while their optical band gap (Eg) increased with R. The a-SiCx:H thin film grown at higher R was found to be smoother than that grown at lower R. When the RF power density, P and R were fixed, the growth rate of a-SiCx:H thin films decreased with Ts, while their n increased with Ts. It was found that Eg slightly increased with Ts, and the film became rough at higher Ts. When Ts, P and R were fixed, the growth rate of a-SiCx:H thin films increased with the RF power density, while their n only slightly increased and Eg slightly decreased with the RF power density. It was found that the RF power density had a large impact on the roughness of a-SiCx:H thin films.

Measurements on densities (ρ), viscosities (η), and refractive indices (nD) from (293.15 to 333.15) K and at 0.1 MPa along with the surface tensions (γ) at 298.15 K and 0.1 MPa for binary mixtures of 1,3-dimethyladamantane (1,3-DMA), 1-ethyladamantane (1-EA), and 1,3,5-trimethyladamantane (1,3,5-TMA) with 1-heptanol or cyclohexylmethanol have been carried out over the entire composition range. The experimental data are used to calculate the excess molar volumes (VmE), viscosity deviations (Δη), molar refraction deviations (ΔΦR), and surface tension deviations (Δγ). The VmE, Δη, ΔΦR, and Δγ values have been fitted to the Redlich–Kister polynomial equation. From these excess or deviation functions, the molecular interactions and nonideality of the binary systems are discussed. The results are expected to provide fundamental data for understanding the properties of adamantane derivatives as potential components and the composition optimization of new high energy-density hydrocarbon fuels.

Thermal decomposition of 1,1′-bicyclohexyl, a potential surrogate component of high-density hydrocarbon fuels, was performed in a batch-type reactor to investigate its thermal stability. A first-order kinetic equation is supposed to correlate the decomposition process, and the apparent rate constants, ranging from 0.0223 h–1 at 683 K to 0.1979 h–1 at 713 K, are determined. The Arrhenius parameters are determined with the pre-exponential factor A = 6.22 × 1020 h–1 and the activation energy Ea = 293 kJ·mol–1. Compared with four typical hydrocarbon compounds, the thermal stability trend is observed in the order of n-dodecane ≈ 1,3,5-triisopropylcyclohexane > bicyclohexyl > n-propylcyclohexane > decalin. Cyclohexane and cyclohexene are found to be the primary products due to the relatively low energy of the C–C bond connecting the two cyclohexyl rings. Bicyclohexyl decomposes into cyclohexane and cyclohexene equivalently at the beginning of the reaction. A probable mechanism on the basis of quantum calculatio...

For a comprehensive understanding of the properties of 1,3-dimethyladamantane (1,3-DMA) as a new potential candidate of high energy-density hydrocarbon fuels, densities, viscosities, surface tensions, and refractive indices for binary mixtures of 1,3-DMA with each of four C10 alkanes, n-decane, butylcyclohexane, decalin, and exo-tetrahydrodicyclopentadiene (JP-10), are determined over the whole composition range at different temperatures ranging from (293.15 to 363.15) K and atmospheric pressure (0.1 MPa). The excess molar volume (VmE), the viscosity deviation (Δη), the surface tension deviation (Δγ), and the refractive index deviation (ΔnD) for these binary systems are calculated. All of the VmE values are negative over the whole composition range for these systems, and they show slight changes against the temperature. The Δη values for the systems except 1,3-DMA + JP-10 are negative, and the absolute values decrease obviously with rising temperature. The Δγ gives clearly negative values for the system o...

The thermal stability of n-nonane and n-undecane, as the model endothermic hydrocarbon fuels, was evaluated by determining the content change of produced aromatics during the thermal cracking process. The 1H nuclear magnetic resonance spectroscopy (1H NMR), along with the high-performance liquid chromatography (HPLC) and the gas chromatography/mass spectrometry (GC/MS) analyses, is mainly considered to follow the formation of aromatics in the liquid cracking residues of the n-alkanes. The results of the aromatic contents obtained from these three analytical methods show satisfactory agreements. The 1H NMR method also gives the olefin content and the branching index of the liquid residues. The changes of the aromatics, olefins and branching index against the temperature directly reflect the thermal stability of the n-alkanes. Based on the results from 1H NMR, HPLC and GC/MS, a scheme of the formation of aromatics from the thermal cracking of n-alkanes is discussed.

While recent insights indicate that the transcription factor Krüppel-like factor 4 (KLF4) is indispensable for vascular homeostasis, its exact role in proliferation and angiogenesis and how it functions remain unresolved. Thus, the aim of the present study was to evaluate the role of KLF4 in the proliferations of endothelial and vascular smooth muscle cells, as well as the angiogenesis. The overexpression of KLF4 in endothelial cells significantly impaired tube formation. KLF4 inhibited the formation of a vascular network in implanted Matrigel plugs in nude mice. Importantly, we found that KLF4 significantly upregulated the miR-15a expression in endothelial cells and vascular smooth muscle cells, and conversely, KLF4 depletion reduced the amount of miR-15a. Furthermore, KLF4 blocked cell cycle progression and decreased cyclin D1 expression in endothelial cells and vascular smooth muscle cells through the induction of miR-15a. Intriguingly, the delivery of a miR-15a antagomir to nude mice resulted in marked attenuation of the anti-angiogenic effect of KLF4. Collectively, our present study provide the first evidence that miR-15a as a direct transcriptional target of KLF4 that mediates the anti-proliferative and anti-angiogenic actions of KLF4, which indicates that KLF4 upregulation of miR-15a may represent a therapeutic option to suppress proliferative vascular disorders.

The densities and viscosities of mixtures of a hydrocarbon fuel (JP-10) with methyl tert-butyl ether (MTBE) or ethyl tert-butyl ether (ETBE) were determined at different temperatures (293.15, 298.15, 303.15, 308.15 and 313.15) K, over the entire composition range. Excess molar volumes, viscosity deviation and excess Gibbs energies of activation of mixtures were calculated and fitted to the Redlich–Kister equation. The excess molar volumes are negative over the entire range of composition. The viscosity data have been correlated with several semi-empirical equations. The thermodynamic functions of activation were also calculated. The refractive indices of the systems were also measured for temperatures of (293.15, 303.15 and 313.15) K. The results provide important information on the research and application of JP-10 and fuel ethers as additives.

The introduction of light scattering in the photoanodes of dye-sensitized solar cells is one of the most effective approaches to enhance their photovoltaic performance. In this work, we prepared submicron SiO2/TiO2 core/shell particles and embedded these particles in the nanostructured TiO2 photoanodes for light to scatter in the dye-sensitized solar cells. Due to the large difference in the refractive index between the SiO2 core and the TiO2 shell, the embedded submicron SiO2/TiO2 core/shell particles showed strong light scattering effect. Light absorbance of the dyed photoanode with the embedded SiO2/TiO2 particles for light scattering was found to be three times stronger than the one without light scattering particles over a wide wavelength range. The power conversion efficiency of dye-sensitized solar cells was increased by about 50% after the introduction of light scattering SiO2/TiO2 core/shell particles in the photoanode. This work will provide a base for further enhancement in the photovoltaic performance of dye-sensitized solar cells by optimizing the submicron SiO2/TiO2 core/shell particles and the photoanodes.

In this work, we synthesized nonaggregated YAG:Ce3+ phosphor powders using the molten salt synthesis method. The effects of synthesis temperature and time on the crystallization process, microstructures, and luminescent properties of the YAG:Ce3+ phosphors were studied. The results indicate that pure YAG:Ce3+ phosphors can be obtained at about 400 °C using NaNO2–KNO2 as the molten flux. Optimal synthesis conditions and Ce3+ doping concentration for the best luminescent properties for YAG:Ce3+ phosphors were determined.

High manganese twinning-induced plasticity (TWIP) steel is a new kind of structural material and possesses both high strength and superior plasticity and can meet the weight-lightening requirement for manufacturing vehicle body. The excellent formability of the TWIP steel comes from the extraordinary strain hardening effect during plastic deformation. The reduction of specific weight by aluminum alloying and strain hardening effect can lead to an effective weight reduction of the steel components, and provide a better choice for materials in vehicle body design. The TWIP effect in high Mn steels is generally associated with the successive workhardening generated by twins and influenced by some factors, such as Mn content, Al addition revealed by stacking fault energy (SFE), grain size, deformation temperature and strain rate. The present review introduces some aspects of the TWIP steels relating to their physical metallurgy, influencing factors associated with their deformation mechanisms, and a prospect for the future investigation is also described. Moreover, as a potential candidate for replacing Ni-Cr austenitic stainless steel, researches on the oxidation behavior and corrosion resistance of Fe-Mn-Al-C system steels are also reviewed.

Aluminum-doped ZnO (AZO) thin films are usually used as transparent conductors. For practical applications, however, the relatively high refractive index of AZO can lead to high optical reflection. In this work, we modified the optical properties of AZO thin films by adding different amounts of SiO2 into the AZO thin films to prepare the AZO-SiO2 composite thin films. The AZO-SiO2 films were deposited on quartz substrates using a co-sputtering deposition method. It was shown that the refractive index of the AZO-SiO2 thin films consistently decreased with the amount of SiO2 contained in the films. In the meantime, the resistivity of the AZO-SiO2 thin films was found to increase with the SiO2 content in the films. The effects of the deposition conditions on the optical and electrical properties of the AZO-SiO2 thin films were systematically investigated.

Oxidative stress and impaired antioxidant defense are believed to be contributors to the cardiovascular aging process. The transcription factor nuclear factor-E2-related factor 2 (Nrf2) plays a key role in orchestrating cellular antioxidant defenses and maintaining redox homeostasis. Our previous study showed that Exendin-4, a glucagon-like peptide-1 analog, alleviates angiotensin II (ANG II)-induced vascular smooth muscle cell (VSMC) senescence by inhibiting Rac1 activation via cAMP/PKA (Zhao L, Li AQ, Zhou TF, Zhang MQ, Qin XM. Am J Physiol Cell Physiol 307: C1130–C1141, 2014). The objective of this study is to investigate if Nrf2 mediates the antisenescent effect of Exendin-4 in ANG II-induced VSMCs. Here we report that Exendin-4 triggered Nrf2 nuclear translocation, a downstream target of cAMP-responsive element-binding protein (CREB) and expressions of antioxidant genes heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase-1 (NQO-1) in a dose- and time-dependent manner. In addition, knock-down of Nrf2 attenuated the inhibitory effects of Exendin-4 on ANG II-induced superoxidant generation and VSMC senescence. PKA/CREB pathway participated in the upregulations of HO-1 and NQO-1 induced by Exendin-4. Notably, our study revealed that Exendin-4 dose-dependently increased the acetylation of Nrf2 and the recruitment of transcriptional coactivator CREB binding protein (CBP) to Nrf2. The Exendin-4-induced Nrf2 transactivation was diminished in the presence of CBP small interfering RNA. Microscope imaging of Nrf2, as well as immunoblotting for Nrf2, showed that the Exendin-4-evoked Nrf2 acetylation favored its nuclear retention. Importantly, CBP silencing attenuated the suppressing effects of Exendin-4 on ANG II-induced VSMC senescence and superoxidant production. In conclusion, these results provide a mechanistic insight into how Nrf2 signaling mediates the antisenescent and antioxidative effects induced by Exendin-4 in VSMCs.

Based on Tрновский’s displacement field, equivalent strain expression was derived. And according to the dynamic recrystallization (DRX) critical strain, DRX process was determined by equivalent strain. It was found that equivalent strain distribution in deformed specimen is inhomogeneous, and it increases with increasing true strain. Under a certain true strain, equivalent strains at the center, demisemi radius or on tangential plane just below the surface of the specimen are higher than the true strain. Thus, micrographs at those positions can not exactly reflect the true microstructures under the certain true strain. With increasing strain rate, the initial and finish time of DRX decrease. The frozen microstructures of 20Mn23AlV steel with the experimental condition validate the feasibility of predicting DRX process by equivalent strain.

The heavy plate used for offshore structure is one of the important strategic products. In recent years, there is an increasing demand for heavy shipbuilding steel plate with excellent weldability in high heat input welding. During the thermal cycle, the microstructure of the heat affected zone (HAZ) of plates was damaged, and this markedly reduced toughness of HAZ. So, how to improve the toughness of HAZ has been a key subject in the fields of steel research. Oxide metallurgy is considered as an effective way to improve toughness of HAZ, because it could be used to retard grain growth by fine particles, which are stable at the high temperature.The high strength steel plate, which satisfies the low temperature specification, has been applied to offshore structure. Excellent properties of the plates and welded joints were obtained by oxide metallurgy technology, latest controlled rolling and accelerated cooling technology using Ultra-Fast Cooling (an on-line accelerated cooling system). The 355MPa-grade high strength steel plates with normalizing condition were obtained, and the steels have excellent weldability with heat input energy of 79~287kJ/cm, and the nil ductility transition (NDT) temperature was -70°C, which can satisfy the construction of offshore structure in cold regions.

There is a strong need for cost reduction in manufacturing crystalline silicon solar cells, and one of the approaches is to merge two steps of silicon wafer processing into one step without degrading the performance of solar cells. In this work, we intended to employ the spin-on doping (SOD) method for the purpose of dual tasks, phosphorus diffusion to form n+ emitters and antireflection coating (ARC) to reduce optical reflection. Different from the commercial SOD solutions based on SiO2, we used tetraethylorthosilicate (TEOS) to prepare SOD solutions containing different concentrations of phosphorus acid as the phosphorus doping source. We first investigated the dependence of the sheet resistance of the n+ emitters on the concentration of phosphorus acid in the SOD solution as well as the thermal diffusion temperature and time. It was found that all these three factors can effectively influence the sheet resistance of the n+ emitters, suggesting a relatively easier optimization process for forming n+ emitters using the SOD method. The SOD thin films formed after the thermal diffusion process were found to be SiO2 films. We then investigated the antireflection properties of the as-grown SOD thin films, and found that they can effectively reduce the optical reflection of silicon wafers.

Microcrystalline silicon (μc-Si) thin films are widely used for silicon thin film solar cells, especially in the high performance tandem solar cells which comprise an amorphous silicon junction at the top and a μc-Si junction at the bottom. One of the major factors affecting the photovoltaic properties of μc-Si thin film solar cells of thin films is the quality of the μc-Si thin films. In this work, we investigated the effect of substrates on the crystallization characteristics and growth behaviors of μc-Si thin films grown by the plasma enhanced chemical vapor deposition method (PECVD), and found that substrates have a strong effect on the crystallization characteristics of μc-Si thin films. In addition, the growth rate of μc-Si thin films was also highly influenced by the substrates. Three types of substrates, quartz glass, single crystalline silicon and thermally oxidized single crystalline silicon, were used for growing μc-Si thin films from SiH4/H2 with a flow rate ratio 2:98 at different temperatures. Crystallization characteristics of these μc-Si thin films were studied by Raman scattering and X-ray diffraction techniques.

Amorphous silicon nitride (SiNX:H) thin films grown by the plasma enhanced chemical vapor deposition (PECVD) method are presently the most important antireflection coatings for crystalline silicon solar cells. In this work, we investigated the optical properties and chemical bonding characteristics of the amorphous SiNX:H thin films deposited by PECVD. Silane (SiH4) and ammonia (NH3) were used as the reactive precursors. The dependence of the growth rate and refractive index of the SiNX:H thin films on the SiH4/NH3 gas flow ratio was studied. The chemical bonding characteristics and the surface morphologies of the SiNX:H thin films were studied using the Fourier transform infrared spectroscopy and atomic force microscopy, respectively. We also investigated the effect of rapid thermal processing on the optical properties and surface morphologies of the SiNX:H thin films. It was found that the rapid thermal processing resulted in a decrease in the thickness, increase in the refractive index, and coarser surfaces for the SiNX:H thin films.

Anatase TiO 2 nanowires with a diameter of 5–10 nm and length of 500 nm to 2 μm have been successfully synthesized by modifying TiO 2 nanoparticles (P25) using the microwave heating method. The microwave power, reaction pressure, and reaction time for the synthesis of TiO 2 nanowires were 500 W, 0.5–3.0 MPa (corresponding to a temperature range of 175–260), and 40–70 min, respectively. X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and the BET techniques were used to investigate the phase structures, morphologies, and specific surface areas of the TiO 2 nanowires. The effects of reaction time, pressure, and different post-treatment processes on the microstructures of TiO 2 nanowires were discussed. It has been shown that the microwave heating method is efficient in transforming TiO 2 nanoparticles to anatase TiO 2 nanowires.

In the present work, (1−x)(0.935Bi0.5Na0.5TiO3–0.065BaTiO3)–xKNbO3 (BNT–BT–KN, BNT–BT–100xKN) ceramics with x ranging from 0 to 0.1 were prepared by the conventional ceramic fabrication process. A large electrostrictive coefficient of ∼10−2 m4 C−2 is obtained with the composition x ranging from 0.02 to 0.1, which is close to the well-known electrostrictive material Pb(Mg1/3Nb2/3)O3. Under an electric field of 4 kV/mm, the electrostrictive strain can reach as high as 0.08%. Besides, the electric field induced strain behavior indicates a temperature independent behavior within the temperature range of 20 to 150°C. The large electrostrictive strain is suggested to be ascribed to the formation of non-polar (NP) phase developed by the KNbO3 substitution, and the high electrostrictive coefficient of BNT–BT–KN ceramics makes them great candidates to be applied in the new solid-state actuators.

A novel technique, the pulsed-laser-induced liquid-deposition (PLLD) method, has been employed to grow nanocrystalline TiO2 films on fluorine-doped tin-oxide-coated (FTO) glass substrates at room temperature. The PLLD method was implemented by directing a pulsed laser into a liquid precursor and depositing the photosynthesized nanocrystalline TiO2 on an FTO glass substrate immersed in the liquid precursor. The as-grown nanocrystalline TiO2 films were found to have a rutile crystal structure and consist of a number of flower-like TiO2 crystal units arrayed together on the FTO glass substrate. Each of the flower-like TiO2 crystal units was composed of many nanostructured TiO2 whiskers, and their building blocks were found to be bundles of TiO2 nanorods with diameter of about 5 nm. The growth of these TiO2 nanorods is highly anisotropic, with the preferential growth direction along [001]. As-grown nanocrystalline TiO2 films were annealed at 450°C in air for 30 min for the applications of dye-sensitized solar cells, and the nanostructured characteristics with good porosity were preserved after annealing. A preliminary dye-sensitized solar cell was built based on the annealed nanocrystalline TiO2 film. The results suggest that the PLLD method is a promising technique for growing nanocrystalline TiO2 films for photovoltaic applications.

Ca1-xCuO2 contains an infinite one-dimensional edge-sharing [CuO2] chain and is readily fabricated by a solid-state reaction in a moderate oxygen atmosphere (10-12 bar). High-temperature (890-1170 degrees C) and high-pressure (3.0-5.0 GPa) sintering was used to study the stability of the Ca1-xCuO2 samples. We found that the Ca1-xCuO2 chain structure remained stable at high temperature, high pressure and high oxygen pressure. However, we found that the stoichiometry of the Ca1-xCuO2 compound is modified after high-pressure sintering, suggesting that high-pressure sintering may increase the calcium content of the Ca1-xCuO2 chain structure. (C) 2010 Elsevier B.V. All rights reserved.

Primary nonalcoholic fatty liver disease is one of the most common forms of chronic liver diseases and is associated with insulin-resistant states such as diabetes and obesity. Recent work has revealed potential implications of peroxisome proliferator-activated receptor-δ (PPARδ) in lipid homeostasis and insulin resistance. In this study, we examined the effect of PPARδ on sterol regulatory element-binding protein-1 (SREBP-1), a pivotal transcription factor controlling lipogenesis in hepatocytes. Treatment with GW0742, the PPARδ agonist, or overexpression of PPARδ markedly reduced intracellular lipid accumulation. GW0742 and PPARδ overexpression in hepatocytes induced the expression of insulin-induced gene-1 (Insig-1), an endoplasmic reticulum protein braking SREBP activation, at both the mRNA and the protein levels. PPARδ inhibited the proteolytic processing of SREBP-1 into the mature active form, thereby suppressing the expression of the lipogenic genes fatty acid synthase, stearyl CoA desaturase-1, and acetyl coenzyme A carboxylase. Our results revealed a direct binding of PPARδ to a noncanonical peroxisome proliferator responsive element motif upstream of the transcription initiation site of human Insig-1. The disruption of this site diminished the induction of Insig-1, which suggested that Insig-1 is a direct PPARδ target gene in hepatocytes. Knockdown of endogenous Insig-1 attenuated the suppressive effect of GW0742 on SREBP-1 and its target genes, indicating PPARδ inhibited SREBP-1 activation via induction of Insig-1. Furthermore, overexpression of PPARδ by intravenous infection with the PPARδ adenovirus induced the expression of Insig-1, suppressed SREBP-1 activation, and, consequently, ameliorated hepatic steatosis in obese db/db mice. Conclusion: Our study reveals a novel mechanism by which PPARδ regulates lipogenesis, suggesting potential therapeutic applications of PPARδ modulators in obesity and type 2 diabetes, as well as related steatotic liver diseases. (HEPATOLOGY 2008.)

Objective— Endothelial activation is implicated in atherogenesis and diabetes. The role of peroxisome proliferator-activated receptor-δ (PPAR-δ) in endothelial activation remains poorly understood. In this study, we investigated the anti-inflammatory effect of PPAR-δ and the mechanism involved. Methods and Results— In human umbilical vein endothelial cells (HUVECs), the synthetic PPAR-δ ligands GW0742 and GW501516 significantly inhibited tumor necrosis factor (TNF)-α–induced expression of vascular cell adhesion molecule-1 and E-selectin (assayed by real-time RT-PCR and Northern blotting), as well as the ensuing endothelial-leukocyte adhesion. Activation of PPAR-δ upregulated the expression of antioxidant genes superoxide dismutase 1, catalase, and thioredoxin and decreased reactive oxygen species production in ECs. Chromatin immunoprecipitation assays showed that GW0742 switched the association of BCL-6, a transcription repressor, from PPAR-δ to the vascular cell adhesion molecule (VCAM)-1 promoter. Small interfering RNA reduced endogenous PPAR-δ expression but potentiated the suppressive effect of GW0742 on EC activation, which suggests that the nonliganded PPAR-δ may have an opposite effect. Conclusions— We have demonstrated that ligand activation of PPAR-δ in ECs has a potent antiinflammatory effect, probably via a binary mechanism involving the induction of antioxidative genes and the release of nuclear corepressors. PPAR-δ agonists may have a potential for treating inflammatory diseases such as atherosclerosis and diabetes.

Ca 2+ sparks as the elementary intracellular Ca 2+ release events are instrumental to local control of Ca 2+ signaling in many types of cells. Here, we visualized neural Ca 2+ sparks in dorsal root ganglion (DRG) sensory neurons and investigated possible role of DRG sparks in the regulation of secretion from the somata of the cell. DRG sparks arose mainly from type 3 ryanodine receptor Ca 2+ release channels on subsurface cisternae of the endoplasmic reticulum, rendering a striking subsurface localization. Caffeine- or 3,7-dimethyl-1-(2-propynyl)xanthine-induced store Ca 2+ release, in the form of Ca 2+ sparks, triggered exocytosis, independently of membrane depolarization and external Ca 2+ . The spark-secretion coupling probability was estimated to be between 1 vesicle per 6.6 sparks and 1 vesicle per 11.4 sparks. During excitation, subsurface sparks were evoked by physiological Ca 2+ entry via the Ca 2+ -induced Ca 2+ release mechanism, and their synergistic interaction with Ca 2+ influx accounted for ≈60% of the Ca 2+ -dependent exocytosis. Furthermore, inhibition of Ca 2+ -induced Ca 2+ release abolished endotoxin-induced secretion of pain-related neuropeptides. These findings underscore an important role for Ca 2+ sparks in the amplification of surface Ca 2+ influx and regulation of neural secretion.

Nanometric ammonium aluminum carbonate hydroxide (AACH) with a particle size less than 5 nm was produced from ammonium aluminum sulfate and ammonium hydrocarbonate under an optimized adding condition, and phase transformations of the AACH on heating and the effect of α-Al 2 O 3 seeding on the transformation kinetics were investigated. The phase transformation sequence of AACH on heating was found to be AACH → amorphous Al 2 O 3 → γ-Al 2 O 3 → θ-Al 2 O 3 → α-Al 2 O 3 , where the formation temperatures of θ-Al 2 O 3 and α-Al 2 O 3 are 850° and 1050°C, respectively. The phase transformation sequence on heating of the AACH seeded with 5 wt% α-Al 2 O 3 seed crystals 100 nm in diameter was found to be AACH → amorphous Al 2 O 3 → θ-Al 2 O 3 → α-Al 2 O 3 . γ-Al 2 O 3 was not observed, and the θ-Al 2 O 3 → α-Al 2 O 3 transformation temperature was reduced to 900°C by the seeding. By calcining the γ-AlOOH, the AACH, and the seeded AACH at their lowest temperatures to transform completely to α-Al 2 O 3 (i.e., about 1200°, 1100°, and 900°C, respectively), α-Al 2 O 3 powders have been obtained with mean particle sizes of about 150, 70, and 30 nm, respectively. The α-Al 2 O 3 powder produced from the seeded AACH has the highest sintering reactivity. After sintering at 1400°C for 2 h, relative densities of the powder compacts of α-Al 2 O 3 obtained by calcining γ-AlOOH, AACH, and the seeded AACH are 74.3%, 95.0%, and 98.5%, respectively.

Magnetic ions such as Fe 3+ are usually doped into ferroelectric oxides in order to obtain multiferroic properties. Fe 3+ as an acceptor dopant (substituted for Ti 4+ ) in BaTiO 3 ceramics usually promotes the formation of the hexagonal phase of BaTiO 3 . Based on the consideration of charge compensation for the acceptor dopant Fe 3+ in Fe-doped BaTiO 3 ceramics, we introduced donor dopants into the ceramics, and investigated the effects of donor doping on the phase structures and magnetic properties of the ceramics. We demonstrated that the phase structures of the Fe-doped BaTiO 3 can be readily controlled by donor doping. In this work, we prepared Fe-doped BaTiO 3 ceramics at a doping concentration of 10 at% (or Ba(Ti 0.9 Fe 0.1 )O 3 ) as a model system, and employed Nb 5+ as the donor dopant for a charge compensation for the acceptor dopant Fe 3+ . It was found that the formation of the hexagonal phase in Ba(Ti 0.9 Fe 0.1 )O 3 was consistently suppressed by Nb 5+ donor doping. The magnetic properties of the Ba(Ti 0.9 Fe 0.1 )O 3 ceramics were strongly influenced by Nb 5+ doping.

The evolution of superconducting transition of CuBa 2 Ca 3 Cu 4 O 10+δ (i.e. Cu -1234) superconductor has been studied by using diamond anvil cell technique. The Tc of Cu -1234 can be enhanced continuously from ambient reaching to 123 K at 15 GPa. This seems the one more system besides Hg -12( n -1) n which demonstrate the positive pressure effect on Tc over a wide pressure range above 10 GPa.

The density functional theory (DFT) calculations at the M06-2X/6-31++G(d,p) level have been performed to explore the molecular structure, electronic structure, C-H bond dissociation enthalpy, and reaction enthalpies for five isodesmic reactions of a high energy-density endothermic hydrocarbon fuel JP-10. On the basis of the calculations, it is found that the carbonium ion C-6 isomer formed from the catalytic cracking at the C6 site of JP-10 has the lowest energy, and the R-5 radical generated from the thermal cracking at the C5 site of JP-10 is the most stable isomer. Furthermore, a series of hypothetical and isodesmic work reactions containing similar bond environments are used to calculate the reaction enthalpies for target compounds. For the same isodesmic reaction, the reaction enthalpy of each carbon site radical has also been calculated. The present work is of fundamental significance and strategic importance to provide some valuable insights into the component design and energy utilization of advanced endothermic fuels.

Density functional theory (DFT) calculations have been carried out to investigate the thermal cracking pathways of JP-10, a high energy density hydrocarbon fuel. Thermal cracking mechanisms are proposed, as supported by our previous experimental results (Xing et al. in Ind Eng Chem Res 47:10034–10040, 2008). Using DFT calculations, the potential energy profiles of the possible thermal cracking pathways for all of the diradicals obtained from homolytic C–C bond cleavage of JP-10 were derived and are presented here. The products of the different thermal cracking pathways are in good agreement with our previous experimental observations.

Objective : Laminar shear stress plays critical roles in vascular homeostasis and exerts various metabolic effects on endothelial cells (ECs). Stearoyl-CoA desaturase-1 (SCD1), which catalyzes the biosynthesis of monounsaturated fatty acids, affects the lipid composition and fluidity of the cell membrane. Thus, we examined the effect of laminar flow on SCD1 expression in ECs. Methods : A flow chamber was used to impose a laminar shear stress on a confluent monolayer of human vascular ECs. The expression of SCD1 was examined using real-time RT-PCR and Northern and Western blotting. Immunohistochemical staining was used to assess the expression of SCD1 in Sprague–Dawley rat arteries, including the sites of arterial bifurcation. Results : Laminar shear stress (12 dyn/cm2, 12 h) markedly increased the gene expression of SCD1 in ECs. The flow-induced SCD1 expression was attenuated by peroxisome proliferator-activated receptor (PPAR)-γ antagonists both in vitro and in vivo . Troglitazone and rosiglitazone significantly increased the gene expression of SCD1. Furthermore, overexpression of a constitutively active PPARγ induced the expression of SCD1 in ECs. Immunohistochemical study of cross-sections from rat celiac arteries revealed that endothelial expression of SCD1 was substantially higher on the medial division apex, where the shear stress is high and more laminar, than the lateral aspect, where the shear stress is low and unsteady. Conclusion : These in vitro and in vivo results demonstrate that laminar flow increased the expression of SCD1 in endothelium through a PPARγ-specific mechanism, which may contribute to the shear stress-mediated protective roles in ECs.

Chemokines are important mediators in immune responses and inflammatory processes. Calcitonin gene-related peptide (CGRP) is produced in dorsal root ganglion (DRG) neurons. In this study, CGRP radioimmunoassay was used to investigate whether the chemokines CCL2 and CXCL1 could trigger CGRP release from cultured DRG neurons of neonatal rats and, if so, which cellular signaling pathway was involved. The results showed that CCL2 and CXCL1 ( approximately 5-100 ng/ml) evoked CGRP release and intracellular calcium elevation in a pertussis toxin (PTX)-sensitive manner. The CGRP release by CCL2 and CXCL1 was significantly inhibited by EGTA, omega-conotoxin GVIA (an N-type calcium channel blocker), thapsigargin, and ryanodine. Pretreatment of DRG neurons for 30 min with the inhibitors of phospholipase C (PLC) and protein kinase C (PKC) but not mitogen-activated protein kinases (MAPKs) significantly reduced CCL2- or CXCL1-induced CGRP release and intracellular calcium elevation. Intraplantar injection of CCL2 or CXCL1 produced hyperalgesia to thermal and mechanical stimulation in rats. These data suggest that CCL2 and CXCL1 can stimulate CGRP release and intracellular calcium elevation in DRG neurons. PLC-, PKC-, and calcium-induced calcium release from ryanodine-sensitive calcium stores signaling pathways are involved in CCL2- and CXCL1-induced CGRP release from primary nociceptive neurons, in which chemokines produce painful effects via direct actions on chemokine receptors expressed by nociceptive neurons.

On the basis of two-dimensional coupled-wave theory, diffraction properties of ultrashort pulsed beams (UPBs) generated from volume holographic gratings with arbitrary boundaries are studied. The resulting differential coupled equations are solved numerically by a two-dimensional Runge–Kutta method. The effects of the grating boundaries on the intensity distributions of the diffracted and transmitted pulsed beams in spectral and temporal domains are presented, and the effects on the Bragg selectivity bandwidth, the diffracted bandwidth and the total diffraction efficiency of the gratings are also given. Simulation results show that use of a characteristic grating will result in distorted profiles for the diffracted beam and that truncated grating shapes significantly improve the output beam quality. This study presents the possibility of shaping a broadband UPB by controlling the boundaries of local volume hologram gratings.