3,574 research outputs found
STRUCTURAL AND ELECTROOPTIC PROPERTIES OF LASER ABLATED BI4TI3O12 THIN-FILMS ON SRTIO3(100) AND SRTIO3(110)
Bi4Ti3O12 thin films have been grown by laser ablation on SrTiO3(100) and SrTiO3(110) substrates. Substrate surface orientation is found to be an important growth parameter which determines crystal axis orientation, grain growth behavior, and electro-optic properties of the Bi4Ti3O12 thin films. The films grown on SrTiO3(110) shows a ferroelectric phase transition near 720-degrees-C and a large quadratic electro-optic effect with the effective coefficient 1.1 X 10(-16) m2/v 2.open1135sciescopu
Analysis of Slab and Slab Heater Cover in a Compact Endless Cast and Rolling Mill Process using Finite Element Methods
Compact Endless cast and rolling Mill (CEM) processes were developed and used to fabricate steel products such as steel slabs. However, the coiling furnace in this process was very expensive, so a new layout was suggested. As the coiling furnace was removed, the interval among the slab heaters had to be increased. This led to a temperature drop in the slab. The temperature distribution of the slab impacts quality, so new layout was developed. This paper presents a Finite Element Method (FEM) simulation of thermal behavior in the slab employing slab heater covers. All of the simulation results were verified by comparing them with experimental results. The slab moving distance at which the temperature was saturated during the process was determined to consider the steady-state and analyze the temperature distribution of the slab and slab heater. Those results revealed that the efficiency of heat conservation increased by more than 50% using the slab heater cover. Finally, a sensitivity analysis of the slab heater cover was conducted with respect to the cover design. The effects of insulator thickness, the gap distance between the slab and cover, and material parameters such as density, and specific heat were investigated to optimize the design of the slab heater cover to produce the best quality slab.11Ysciescopuskc
Crystallization and preliminary X-ray crystallographic analysis of SEDL
SEDL (known also as sedlin) is a 140 amino-acid protein with a putative role in endoplasmic reticulum-to-Golgi transport. Several missense mutations and deletion mutations in the SEDL gene, which result in protein truncation by frame shift, are responsible for spondyloepiphyseal dysplasia tarda, a progressive skeletal disorder. The protein is identical to MIP-2A, which was shown to interact physically with c-myc promotor-binding protein 1 (MBP-1) and relieve the regulatory role of MBP-1 as a general transcription repressor. In order to gain insights into the function of SEDL by structural analysis, the protein was overexpressed and crystallized as a first step. SEDL was overexpressed in Escherichia coli and crystallized using the hanging-drop vapour-diffusion method at 298 K. The crystals belong to the orthorhombic space group C2221, with unit-cell parameters a = 46.69, b = 101.30, c = 66.15 A. The unit cell is likely to contain one molecule of SEDL, with a crystal volume per protein mass (VM) of 2.36 A3 Da-1 and a solvent content of about 47.9% by volume. A native data set to 2.8 A resolution was obtained from a flash-cooled crystal using synchrotron radiation.open1
Nanoscale strain mapping in battery nanostructures
Coherent x-ray diffraction imaging is used to map the local three dimensional strain inhomogeneity and electron density distribution of two individual LiNi0.5Mn1.5O4-δ cathode nanoparticles in both ex-situ and in-situ environments. Our reconstructed images revealed a maximum strain of 0.4%. We observed different variations in strain inhomogeneity due to multiple competing effects. The compressive/tensile component of the strain is connected to the local lithium content and, on the surface, interpreted in terms of a local Jahn-Teller distortion of Mn 3+. Finally, the measured strain distributions are discussed in terms of their impact on competing theoretical models of the lithiation process. © 2014 AIP Publishing LLC
Effect of surfactant concentration variation on the thermoelectric properties of mesoporous ZnO
The electrical and thermal conductivities and the Seebeck coefficient of mesoporous ZnO thin films were investigated to determine the change of their thermoelectric properties by controlling surfactant concentration in the mesoporous ZnO films, because the thermoelectric properties of mesoporous ZnO films can be influenced by the porosity of the mesoporous structures, which is primarily determined by surfactant concentration in the films. Mesoporous ZnO thin films were successfully synthesized by using sol-gel and evaporation-induced self-assembly processes. Zinc acetate dihydrate and Brij-76 were used as the starting material and pore structure-forming template, respectively. The porosity of mesoporous ZnO thin films increased from 29% to 40% with increasing surfactant molar ratio. Porosity can be easily altered by controlling the molar ratio of surfactant/precursor. The electrical and thermal conductivity and Seebeck coefficients showed a close correlation with the porosity of the films, indicating that the thermoelectric properties of thin films can be changed by altering their porosity. Mesoporous ZnO thin films with the highest porosity had the best thermoelectric properties (the lowest thermal conductivity and the highest Seebeck coefficient) of the films examined. © 2013 Min-Hee Hong et al
Regulatory subunits of PKA define an axis of cellular proliferation/differentiation in ovarian cancer cells
<p>Abstract</p> <p>Background</p> <p>The regulatory subunit of cAMP-dependent protein kinase (PKA) exists in two isoforms, RI and RII, which distinguish the PKA isozymes, type I (PKA-I) and type II (PKA-II). Evidence obtained from a variety of different experimental approaches has shown that the relative levels of type I and type II PKA in cells can play a major role in determining the balance between cell growth and differentiation. In order to characterize the effect of PKA type I and type II regulatory subunits on gene transcription at a global level, the PKA regulatory subunit genes for RIα and RIIβ were stably transfected into cells of the ovarian cancer cell line (OVCAR8).</p> <p>Results</p> <p>RIα transfected cells exhibit hyper-proliferative growth and RIIβ transfected cells revert to a relatively quiescent state. Profiling by microarray revealed equally profound changes in gene expression between RIα, RIIβ, and parental OVCAR cells. Genes specifically up-regulated in RIα cells were highly enriched for pathways involved in cell growth while genes up-regulated in RIIβ cells were enriched for pathways involved in differentiation. A large group of genes (~3600) was regulated along an axis of proliferation/differentiation between RIα, parental, and RIIβ cells. RIα/wt and RIIβ/wt gene regulation was shown by two separate and distinct gene set analytical methods to be strongly cross-correlated with a generic model of cellular differentiation.</p> <p>Conclusion</p> <p>Overexpression of PKA regulatory subunits in an ovarian cancer cell line dramatically influences the cell phenotype. The proliferation phenotype is strongly correlated with recently identified clinical biomarkers predictive of poor prognosis in ovarian cancer suggesting a possible pivotal role for PKA regulation in disease progression.</p
Toxicity assessment of modified Cry1Ac1 proteins and genetically modified insect-resistant Agb0101 rice
Insect-resistant Agb0101 rice was recently developed by modifying the cry1ac1 gene by changing codon usage changes relative to the native truncated cry1ac1 gene. To assess the toxicity of genetically modified Agb0101 rice, we conducted bioinfomational comparisons of the amino acid sequences that are not similar to known toxic proteins. Sufficient quantities of mCry1Ac1 protein were produced in Escherichia coli for in vitro evaluation and animal study. We compared the amino acid sequences and molecular mass. There have the same amino acid sequences and molecular masses after purifying the modified Cry1Ac1 (mCry1Ac1) protein from highly expressed bacteria and genetically modified rice were identical. We also investigated the acute and 90-days oral toxicities. No adverse effects were observed in mice following acute oral exposure to 2,000 mg/ kg body weight mCry1Ac1 protein of body weight and 90 days oral exposure to Agb0101. These results indicate that mCry1Ac1 proteins and Agb0101 rice demonstrate no adverse effects in these tests when applied via gavage and feed, respectively.Key words: Modified Cry1Ac1, food safety assessment, toxicity, insect- resistant rice Agb0101
High-yield isolation of extracellular vesicles using aqueous two-phase system
Extracellular vesicles (EVs) such as exosomes and microvesicles released from cells are potential biomarkers for blood-based diagnostic applications. To exploit EVs as diagnostic biomarkers, an effective pre-analytical process is necessary. However, recent studies performed with blood-borne EVs have been hindered by the lack of effective purification strategies. In this study, an efficient EV isolation method was developed by using polyethylene glycol/dextran aqueous two phase system (ATPS). This method provides high EV recovery efficiency (similar to 70%) in a short time (similar to 15 min). Consequently, it can significantly increase the diagnostic applicability of EVs.113219Ysciescopu
Characterization of Fine Particulate Matter and Associations between Particulate Chemical Constituents and Mortality in Seoul, Korea
Background: Numerous studies have linked fine particles [≤ 2.5 µm in aerodynamic diameter (PM2.5)] and health. Most studies focused on the total mass of the particles, although the chemical composition of the particles varies substantially. Which chemical components of fine particles that are the most harmful is not well understood, and research on the chemical composition of PM2.5 and the components that are the most harmful is particularly limited in Asia
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