Protein coverage on polymer nanolayers leading to mesenchymal stem cell patterning

Interactions of gelatin and albumin with a photo-reactive diphenylamino-s-triazine bridged p-phenylene vinylene polymer (DTOPV) were examined by using surface plasmon resonance (SPR) spectroscopy to explore the effect of the polymer structure on protein coverage of DTOPV nanofilms. The SPR data revealed a significant increase of gelatin adsorption on UV-DTOPV nanofilms, while the adsorption of albumin was decreased by UV exposure in the time frame of the experiment. We also found that the selective adsorption of these proteins was highly dependent on the protein concentration; the highest selectivity of protein adsorption was obtained at the lowest concentration (3.5 μg ml(-1)), while no selective adsorption was confirmed at high concentrations (350 and 1000 μg ml(-1)). The selective attachment of mesenchymal stem cells (MSCs) was directly correlated with the selective adsorption of these proteins onto DTOPV nanofilms. The MSCs attachment onto UV-DTOPV films was promoted with only small mass coverage of gelatin, which led to MSC patterning onto the patterned DTOPV nanofilms successfully. The role of cell adhesion proteins that we found in this study will be a clue to elucidate the complex response of biomolecules on functional polymer nanolayers, and contribute to build up biocompatible surfaces on various advanced materials for the sake of cell engineering and medical implants.     

Optimization of an inclined elliptic impinging jet with cross flow for enhancing heat transfer

This work presents a parametric study and optimization of a single impinging jet with cross flow to enhance heat transfer with two design variables. The fluid flow and heat transfer have been analyzed using three-dimensional compressible Reynolds-averaged Navier–Stokes equations with a uniform heat flux condition being applied to the impingement plate. The aspect ratio of the elliptic jet hole and the angle of inclination of the jet nozzle are chosen as the two design variables, and the area-averaged Nusselt number on a limited target plate is set as the objective function. The effects of the design variables on the heat transfer performance have been evaluated, and the objective function has been found to be more sensitive to the angle of inclination of the jet nozzle than to the aspect ratio of the elliptic jet hole. The optimization has been performed by using the radial basis neural network model. Through the optimization, the area-averaged Nusselt number increased by 7.89% compared to that under the reference geometry.     

Copper-catalyzed, one-pot, three-component synthesis of benzimidazoles by condensation and C-N bond formation

Benzimidazoles were synthesized by the copper-catalyzed, one-pot, three-component reaction of 2-haloanilines, aldehydes, and NaN(3). The reaction was optimized when 2-iodo- or 2-bromoanilines (1.0 equiv), aldehydes (1.2 equiv), NaN(3) (2.0 equiv), 5 mol% of CuCl, and 5 mol % of TMEDA were reacted in DMSO at 120 °C for 12 h. Good yields resulted, and the reaction showed tolerance toward functional groups such as ester, nitro, and chloro. Aliphatic and heteroaromatic aldehydes also afforded the desired products in moderate to good yields.     

Electric dipole moment of Dirac fermionic dark matter

The direct limit of electric dipole moment and direct searches for dark matter by electric dipole interaction are investigated with including the electromagnetic nuclear form factor, in case that the dark matter candidate is a Dirac particle. The electric dipole moment of dark matter constrained by direct searches must be lower than 7×¹⁰−22e cm for dark matter mass of 100 GeV to satisfy the current experimental exclusion limits at XENON10 and CDMS II. The CP violation of electric dipole moment and the dark matter discovery by electric dipole interaction in the future are considered.     

Spinodal twinning of a deformed crystal

We propose the possibility of a spinodal mechanism for deformation twinning in addition to the nucleation and growth mechanism assumed in all existing studies of twinning, using the thermodynamic stability analysis of a homogeneously deformed crystal by examining its energy landscape as a function of strain along the twinning direction obtained from first-principles calculations. Twinning occurs continuously owing to thermodynamic instability with respect to twinning at large shear strains, whereas it can only take place through the nucleation and growth mechanism at small shear strains.     

Hybrid polymer/inorganic nanoparticle blended ternary solar cells

Hybrid polymer/inorganic nanoparticle blended ternary solar cells are reported. These solar cells have an active layer consisting of PbS colloidal quantum dots (CQDs), poly (3‐hexylthiophene) (P3HT), and [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM). Power conversion efficiency (PCE) was improved by incorporating PbS CQDs in the active layer of P3HT:PCBM‐based organic solar cells. As the concentration of PbS CQDs in the hybrid solar cells was increased, PCE was also increased. This improvement resulted from improved charge transfer and also extended light absorption into the near‐infrared. The PCE of the hybrid solar cells was 47% higher than that for reference organic solar cells on average under air mass 1.5 global illumination. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Ge and Ga K-edge EXAFS analyses on the structure of Ge-Ga-S-CsBr glasses

The local structure of Ge and Ga ions in (1 − x)(Ge_0.25Ga_0.10S_0.65)-xCsBr glasses (x = 0.00, 0.05, 0.10 and 0.12) were investigated using extended X-ray absorption fine structure (EXAFS) spectroscopy. CsBr formed [GaS_3/2Br]⁻ structural units in glass while Ge ions remained in GeS_4/2 tetrahedra, unaffected by CsBr addition. Rare-earth ions can be surrounded by Br ions only when CsBr/Ga ratio in glass became larger than unity.     

Measurements of spectral responses for developing fiber-optic pH sensor

In this study, we have fabricated a fiber-optic pH sensor, which is composed of a light source, a pH-sensing probe, plastic optical fibers and a spectrometer, for determining the degree of infection by Helicobacter pylori in the stomach. As pH indicators, phenol red and m-cresol purple are used, and pH liquid solutions are prepared by mixing phenol red or m-cresol purple solutions and various kinds of pH buffer solutions. The light emitted by a light source is guided by plastic optical fibers to the pH liquid solution, and the optical characteristic of a reflected light is changed according to the color variations of the pH indicator in the pH-sensing probe. Therefore, we have measured the intensities and wavelength shifts of the reflected lights, which change according to the color variations of indicators at different pH values, by using a spectrometer for spectral analysis. Also, the relationships between the pH values of liquid solutions and the optical properties of the modulated lights are obtained on the basis of the changes of the colors of indicators.