Properties of Dispersion Casting of Y2O3 Particles in Hypo, Hyper and Eutectic Binary Al-Cu Alloys

In the present work,the dispersion casting of Y-2O-3 particles in aluminum-copper alloy was investigated in terms of microstructural changes with respect to Cu contents of 20 （hypo）,33 （eutectic） and 40 （hyper） wt pct by scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS）.For the fabrication of Al-Cu alloy dispersed Y-2O-3 ceramic particles,stir casting method was employed.In case of Al-20 wt pct Cu alloy （hypoeutectic）,SEM images revealed that primary Al was grown up in the beginning.After that,eutectic phase with well dispersed ceramic particles was formed.In case of eutectic composition,Y-2O-3 particles were uniformly dispersed in the matrix.When the Cu is added into Al up to 40 wt pct （hypereutectic）,primary phase was grown up without any Y-2O-3 ceramic particles in the early stage of solidification.Thereafter, eutectic phase was formed with well dispersed ceramic particles.It can be concluded that Y-2O-3 ceramic particles is mostly dispersed in case of eutectic composition in Al-Cu alloy.     

Sequential hydration with anaerobic and heat treatment increases GABA (γ-aminobutyric acid) content in wheat

γ-Aminobutyric acid (GABA), which displays anti-hypertensive and diuretic effects, is known to be produced in germinated wheat. The effect of sequential hydration combined with anaerobic and heat treatment on the GABA content in wheat was investigated. The GABA content in soft white winter (SWW) and dark northern spring (DNS) wheat was 0.80 and 1.18 mg/100 g, respectively. Both the anaerobic and the heat treatment contributed to the increase of GABA in SWW and DNS wheat. The GABA contents in SWW and DNS wheat was increased by germination for 48 h after sequential hydration with anaerobic and heat treatment at a target moisture content of 35% to 45.65 and 47.40 mg/100 g, respectively. Our results suggest that combined anaerobic and heat treatment after sequential hydration may be used for the preparation of wheat with high GABA content, which can then be used as a natural resource of functional foods.     

Polynomial ARMA model identification for a continuous styrene polymerization reactor using on‐line measurements of polymer properties

The multiinput–multioutput identification for a continuous styrene polymerization reactor using a polynomial ARMA model is carried out by both simulation and experiment. The pseudorandom multilevel input signals are applied for model identification in which input variables are the jacket inlet temperature and the feed flow rate, whereas the output variables are the monomer conversion and the weight‐average molecular weight. The use of a polynomial ARMA model for identification of the multivariable polymerization reaction system is validated by simulation study. For the experimental corroboration, correlations are developed to convert the on‐line measurements of density and viscosity of the reaction mixture to the monomer conversion and the weight‐average molecular weight. The on‐line values of the conversion and weight‐average molecular weight turn out to be in good agreement with the off‐line measurements. Despite the complex and nonlinear features of the polymerization reaction system, the polynomial ARMA model is found to satisfactorily describe the dynamic behavior of the polymerization reactor. Therefore, one may apply the polynomial ARMA model to the optimization and control of polymerization reactor systems. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1889–1901, 2000     

Multiwall carbon nanotube and poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) composite films for transistor and inverter devices

Highly conductive multiwalled carbon nanotube (MWNT)/Poly(3,4-ethylenedioxythiophene) polymerized with poly(4-styrenesulfonate) (PEDOT:PSS) films were prepared by spin coating a mixture solution. The solution was prepared by dispersing MWNT in the PEDOT:PSS solution in water using ultrasonication without any oxidation process. The effect of the MWNT loading in the solution on the film properties such as surface roughness, work function, surface energy, optical transparency, and conductivity was studied. The conductivity of MWNT/PEDOT:PSS composite film was increased with higher MWNT loading and the high conductivity of MWNT/PEDOT:PSS films enabled them to be used as a source/drain electrode in organic thin film transistor (OTFT). The pentacene TFT with MWNT/PEDOT:PSS S/D electrode showed much higher performance with mobility about 0.2 cm2/(V s) and on/off ratio about 5 × 10? compared to that with PEDOT:PSS S/D electrode (～0.05 cm2/(V s), 1 × 10?). The complementary inverters exhibited excellent characteristics, including high gain value of about 30.     

Preparation of TiO<Subscript>2</Subscript> nanotube/nanoparticle composite particles and their applications in dye-sensitized solar cells

Efficiency of dye-sensitized solar cells [DSSCs] was enhanced by combining the use of TiO₂ nanotubes [TNTs] and nanoparticles. TNTs were fabricated by a sol-gel method, and TiO₂ powders were produced through an alkali hydrothermal transformation. DSSCs were constructed using TNTs and TiO₂ nanoparticles at various weight percentages. TNTs and TiO₂ nanoparticles were coated onto FTO glass by the screen printing method. The DSSCs were fabricated using ruthenium(II) (N-719) and electrolyte (I₃/I₃ ^-) dyes. The crystalline structure and morphology were characterized by X-ray diffraction and using a scanning electron microscope. The absorption spectra were measured using an UV-Vis spectrometer. The incident photocurrent conversion efficiency was measured using a solar simulator (100 mW/cm²). The DSSCs based on TNT/TiO₂ nanoparticle hybrids showed better photovoltaic performance than cells made purely of TiO₂ nanoparticles.     

A highly active Ni-Al2O3 catalyst prepared by homogeneous precipitation using urea for internal reforming in a molten carbonate fuel cell (MCFC): Effect of the synthesis temperature

Ni-Al₂O₃ catalysts for use in internal reforming in a molten carbonate fuel cell (MCFC) were prepared by homogeneous precipitation method at various synthesis temperatures. The effects of synthesis temperature on physicochemical properties and catalytic activities of the Ni-Al₂O₃ catalysts were investigated. XRD measurements exhibited that the peak intensity of NiAl₂O₄ in the calcined catalysts increased with higher synthesis temperatures. TPR measurements demonstrated that reduction peaks appeared around 670–680 °C for every synthesis temperature, indicating that the Ni particles interacted strongly with the support. Hydrogen chemisorption results showed that nickel dispersion and nickel surface area decreased in the order: K52_80C > K52_85C > K52_90C > K52_95C > K52_100C. TEM images of the reduced Ni-Al₂O₃ catalysts revealed that the average sizes of Ni particles were 13.1, 13.4 and 15.9 nm for K52_80C, K52_90C and K52_100C, respectively, which means that a higher synthesis temperature yielded a larger Ni particle. The performance of the catalysts in methane steam reforming showed that catalysts prepared at the lowest synthesis temperature (80 °C) exhibited the highest reaction rate. These results suggest that a lower synthesis temperature is favorable to prepare highly active Ni-Al₂O₃ catalysts by the homogeneous precipitation method.     

Microtubule Acetylation Controls MDA-MB-231 Breast Cancer Cell Invasion through the Modulation of Endoplasmic Reticulum Stress

During aggressive cancer progression, cancer cells adapt to unique microenvironments by withstanding various cellular stresses, including endoplasmic reticulum (ER) stress. However, the mechanism whereby cancer cells overcome the ER stress to survive remains to be elucidated. Herein, we demonstrated that microtubule acetylation in cancer cells grown on a stiff matrix promotes cancer progression by preventing excessive ER stress. Downregulation of microtubule acetylation using shRNA or CRSIPR/Cas9 techniques targeting ATAT1, which encodes α-tubulin N-acetyltransferase (αTAT1), resulted in the upregulation of ER stress markers, changes in ER morphology, and enhanced tunicamycin-induced UPR signaling in cancer cells. A set of genes involved in cancer progression, especially focal adhesion genes, were downregulated in both ATAT1-knockout and tunicamycin-treated cells, whereas ATAT1 overexpression restored the gene expression inhibited by tunicamycin. Finally, the expression of ATAT1 and ER stress marker genes were negatively correlated in various breast cancer types. Taken together, our results suggest that disruption of microtubule acetylation is a potent therapeutic tool for preventing breast cancer progression through the upregulation of ER stress. Moreover, ATAT1 and ER stress marker genes may be useful diagnostic markers in various breast cancer types.     

Effects of different Al2O3 support on HDPE gasification for enhanced hydrogen generation using Ni-based catalysts

This study examined the effects of Ni loading on different types of alumina (γ-Al₂O₃, mesoporous Al₂O₃, 13 nm-sized Al₂O₃, and <50 nm-sized Al₂O₃) for high-density polyethylene gasification for enhanced hydrogen generation. The catalytic activity of Ni loaded alumina was observed in the order of 13 nm-sized Al₂O₃> mesoporous Al₂O₃> (<50 nm-sized Al₂O₃) > γ-Al₂O₃ for the gas yield and γ-Al₂O₃> (<50 nm Al₂O₃) > mesoporous Al₂O₃ > 13 nm Al₂O₃ for the oil yield, respectively. In addition, the production of hydrogen from Ni loaded alumina showed an increasing trend in the order of (<50 nm-sized Al₂O₃) > γ-Al₂O₃> 13 nm-sized Al₂O₃.> mesoporous Al₂O₃. In contrast, CO showed the trend as Ni/mesoporous Al₂O₃> Ni/13 nm-sized Al₂O₃> Ni/γ-Al₂O₃> (Ni/<50 nm Al₂O₃). The highest level of hydrogen production from the Ni/<50 nm-sized Al₂O₃ catalyst might be because of its highest Ni dispersion and surface area. The use of Ni-loaded nm-sized alumina could be an excellent method for increased hydrogen production compared to other types of alumina available.