Sensing of oligopeptides using localized surface plasmon resonances combined with Surface-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

Gold nanorods were fixed on an ITO plate and used for the spectroscopic sensing and Surface-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (SALDI-MS) of oligopeptides (angiotensin I). The longitudinal surface plasmon bands of the gold nanorods responded to the 10(-10) M angiotensin solution that was cast on the ITO plate. The SALDI-MS measurements had an ultra-high sensitivity to the angiotensin on the ITO plate. A very small surface density (5 × 10(-19) mol cm(-2)) of angiotensin could be detected at m/z = 1297 with a good signal/noise ratio (S/N = 11). The ITO plate, which was modified with gold nanorods, was found to be effective in collecting angiotensin molecules adjacent to the gold nanorods, and the SALDI processes that were induced by the photoabsorption of the gold nanorods efficiently contributed to the desorption and ionization of the angiotensin.     

Lanthanide selective adsorption by ion-imprinted polymer with chelidonic acid monoamide groups

Lanthanide selective adsorbent with chelidonic acid monoamide group was synthesized based on the ion-imprint method and its adsorption character was investigated. A polymerizable ligand 3 with chelidonic acid group was obtained by condensation of chelidonic acid and 4-aminostyrene. A Nd-complex monomer 7 was synthesized from the obtained ligand 3 and Nd(NO₃)₃. Copolymerization of the Nd-complex monomer, styrene and divinylbenzene afforded Nd-containing polymer 8. To obtain Nd-imprinted polymer 9, Nd ion was removed by hydrochloric acid. A non-imprinted polymer 6 composed by 3, styrene and divinylbenzene was also synthesized. Elemental analysis revealed that the content of chelidonic acid monoamide ligand in the 6 and 9 is 1.70 and 1.56 mmol·g^?1, respectively. BET method indicated that 6 and 9 has specific surface area of 14.7 and 1.51 m²·g^?1, respectively. Nd adsorption experiments revealed 9 exhibits imprinting factor (IF) 4.3 at initial concentration 0.4 mmol-Nd/L, despite 9 has 0.92-fold of ligands and 0.1-fold of specific surface area of 6. Mixed ion solution including Nd, Dy, Cu, Zn, and Co was used as a model solution for an adsorption experiment. 9 exhibits high lanthanide selectivity in a range of pH of 3.0–7.0 and a maximum adsorption amount at pH 3.75, despite 6 shows the maximum at pH 5.0. Density functional theory (DFT) calculation of a model system revealed that the ion-imprint effect and inhibition effect is cause of large adsorption amount of 9.     

Chemical modification of flexible and rigid poly(vinyl chloride) by nucleophilic substitution with thiocyanate using a phase-transfer catalyst

The purpose of this study was to examine the effect of a phase-transfer catalyst on the chemical modification of flexible and rigid poly(vinyl chloride) (PVC) by substituting chloride with thiocyanate (SCN) in order to develop a new process for recycling PVC. The effects of temperature and time on the reaction of a SCN/ethylene glycol (EG) solution on PVC were investigated in the presence and absence of tetrabutylammonium bromide (TBAB) as a phase-transfer catalyst. TBAB was found to accelerate the dehydrochlorination of both flexible and rigid PVC, thus allowing the reaction to take place over shorter reaction times. The substitution yield and substitution/dehydrochlorination ratio were higher in the presence of TBAB than in its absence. By reducing the reaction temperature, the substitution/dehydrochlorination ratio increased, and substitution occurred more rapidly when TBAB was present. The differences between flexible and rigid PVC were negligible. Together, these results indicate that the phase-transfer catalyst TBAB is effective in accelerating the substitution of chloride by SCN. This two-phase reaction allows for the easy separation of the polymer from the solvent without using other chemicals or thermal processes.     

Strengthening of cross tension strength of spot-welded lap joints by increasing the opening angle on the nugget edge

This paper deals with the strengthening of spot-welded lap joints by increasing the opening angle on the nugget edge. Based on the equation proposed by past researchers to predict the strength, the factor necessary for the strengthening was extracted. And, based on this factor, the strengthening of spot-welded lap joints was examined. First of all, in order to increase the opening angle on the nugget edge, the vicinity of the nugget edge was bent with a bending machine. Next, cross tension strength (CTS) tests were conducted into the spot-welded lap joints with various opening angles on the nugget edge. Finally, the relationship between CTS and the opening angels of the nugget edge was clarified. As a result, by increasing the opening angles on the nugget edge, we found that the CTS could be improved by 20%.     

Gas permeability of thin dense films from polymer blend of thermoplastic elastomer and polyolefin

Stretched thin films composed of a thermoplastic elastomer, a polystyrene‐block‐poly(ethylene butylene)‐block‐polystyrene triblock copolymer (SEBS), and polyolefins, poly(ethylene‐co‐ethylacrylate) and poly(ethylene‐co‐propylene), were obtained by blow‐molding, uniaxial stretching, and cooling to room temperature and the gas permeability of the stretched films was investigated. When the as‐blown annealed film was subjected to uniaxial stretching in the machine direction, P_O2 and P_N2 increased with an increase in the stretching ratio K and approached a constant value at high stretching ratios. In addition, P_O2/P_N2 decreased gradually with K and approached a value of 2.95–3.0. The reason for this unique gas permeation behavior is that the molecular mobility of poly(ethylene butylene) chains in a direction normal to the film increases and reaches an equilibrium state at around K = 4.5. The change in gas permeability of the stretched films can be explained using a deformation model for the SEBS matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39386.     

Gas permeation properties for organosilica membranes with different Si/C ratios and evaluation of microporous structures

Organosilica membranes were fabricated using bridged organoalkoxysilanes (bis(triethoxysilyl)methane (BTESM), bis(triethoxysilyl)ethane (BTESE), bis(triethoxysilyl)propane (BTESP), bis(trimethoxysilyl)hexane (BTMSH), bis(triethoxysilyl)benzene (BTESB), and bis(triethoxysilyl)octane (BTESO)) to produce highly permeable molecular sieving membranes. The effect of the organoalkoxysilanes on network pore size and microporous structure was evaluated by examining the molecular size and temperature dependence of gas permeance across a wide range of temperatures. Organosilica membranes showed H₂/N₂ and H₂/CH₄ permeance ratios that ranged from 10 to 150, corresponding to network pore size, and both H₂ selectivity decreased with an increase in the carbon number between 2 Si atoms. Organosilica membranes showed activated diffusion for He and H₂, and a slope of temperature dependence that increased approximate to the increase in the carbon number between 2 Si atoms. The relationship between activation energy and He/H₂ permeance ratio for SiO₂ and organosilica membranes suggested that the molecular sieving can dominate He and H₂ permeation properties via the rigid microporous structure, which was constructed by BTESM and BTESE. With increased in the carbon concentration in silica, polymer chain vibration in organic bridges, which is a kind of solution/diffusion mechanism, can dominate the permeation properties. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4491–4498, 2017     

Improvement of the photostability of isotactic polypropylene by the incorporation of ethylene

The effect of the incorporation of ethylene on the photostability of isotactic poly(propylene) (iPP) was studied with the aim of improving the photostability. iPP was prepared with a random ethylene sequence (ethylene–propylene random copolymer, rPP), and the photooxidative degradation behavior was compared with that of homogeneous iPP. Both samples were thermally post‐treated under vacuum to ensure the same crystallinity. The degradation behavior was studied by infrared spectroscopy (IR), gel permeation chromatography (GPC), and temperature rising elution fractionation (TREF) measurements. The rates of hydroperoxide and carbonyl formation in the irradiated iPP increased with irradiation time for > 192 h, whereas those in the irradiated rPP are almost constant after 96 h. The change in molecular weight with the irradiation time showed similar behavior, suggesting that the degradation reaction in the irradiated rPP was suppressed after 96 h. The degradation behavior of rPP was thought to be due to the dissociation of the methyl group, which leads to the termination of degradation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1863–1867, 2002     

Windowless solid hydrogen target

A windowless solid hydrogen target has been successfully developed for RI-beam-induced nuclear reactions in the RIKEN RI Beam Facility. Hydrogen crystals of high quality were grown reproducibly in a cell bored in a 10 mm thick pure copper plate which was in direct contact with a liquid helium reservoir. Normal hydrogen gas was crystallized directly on the cell wall between 4.7 and 7.3 K. The diameter of the crystal was 25 mm and the thickness was chosen to be either 5 or 10 mm. After crystallization, sidewalls of the cell were separated from both the crystal and cell plate, and removed to a remote position inside a cryostat. Thus, the crystal was self-supported in the cell without any extra material in its neighborhood. No damage was observed in the separating process. The observed hydrogen pressure indicated the crystal temperature of 4.3 K, when the liquid helium reservoir was at 4.2 K, in agreement with the temperature estimated from the heat balance in the crystal. It shows that we can put the crystal temperature close to the reservoir temperature, though we could not confirm the crystal temperature when the reservoir temperature was reduced to 3 K. Hydrogen sublimation rate was calculated from the vapor pressure and pumping condition. The sublimation loss is negligibly small if the crystal is held at 3 K.     

Roles of the Ser146, Tyr159, and Lys163 residues in the catalytic action of 7alpha-hydroxysteroid dehydrogenase from Escherichia coli

Adhesion to collagens by most cell types is mediated by the integrins alpha1beta1 and alpha2beta1. Both integrin alpha subunits belong to a group which is characterized by the presence of an I domain in the N-terminal half of the molecule, and this domain has been implicated in the ligand recognition. Since purified alpha1beta1 and alpha2beta1 differ in their binding to collagens I and IV and recognize different sites within the major cell binding domain of collagen IV, we investigated the potential role of the alpha1 and alpha2 I domains in specific collagen adhesion. We find that introducing the alpha2 I domain into alpha1 results in surface expression of a functional collagen receptor. The adhesion mediated by this chimeric receptor (alpha1-2-1beta1) is similar to the adhesion profile conferred by alpha2beta1, not alpha1beta1. The presence of alpha2 or alpha1-2-1 results in preferential binding to collagen I, whereas alpha1 expressing cells bind better to collagen IV. In addition, alpha1 containing cells bind to low amounts of a tryptic fragment of collagen IV, whereas alpha2 or alpha1-2-1 bearing cells adhere only to high concentrations of this substrate. We also find that collagen adhesion of NIH-3T3 mediated by alpha2beta1 or alpha1-2-1beta1, but not by alpha1, requires the presence of Mn2+ ions. This ion requirement was not found in CHO cells, implicating the I domain in cell type-specific activation of integrins.