An analysis of the spillover effects based on patents and inter-industrial transactions for an emerging blockchain technology

Scientometrics - A simple and robust approach to predict the spillover effects of emerging technologies enables proper formulation of investment strategies. In this study, we propose the method in...     

Fabrication of silica/platinum core-shell particles by electroless metal plating

An electroless metal plating method was used to form Pt shells on sub-micrometer-sized silica (SiO₂) particles fabricated by a sol-gel method. The electroless metal plating method was comprised of three steps: (1) surface-modification of SiO₂ particles with polyvinylpyrrolidone (PVP) (SiO₂/PVP) or poly-diallyldimethylammonium chloride (PDADMAC) (SiO₂/PDADMAC), (2) pre-deposition of Pt nuclei or Pt fine particles on the SiO₂ particles by reducing Pt ions in the presence of SiO₂/PVP particles (SiO₂/PVP-Pt) or SiO₂/PDADMAC particles (SiO₂/PDADMAC-Pt), and (3) growth of the pre-deposited Pt by immersing the SiO₂/PVP-Pt or SiO₂/PDADMAC-Pt particles in a Pt-plating solution. The pre-deposition of Pt nanoparticles was successfully performed for the surface-modified SiO₂ particles since the surface modification possibly strengthened the affinity between the SiO₂ particle surfaces and Pt ions. The Pt nanoparticles were pre-deposited more uniformly in the case of PVP because the pre-deposition took place more slowly for the PVP, which provided uniform surface-modification followed by the uniform pre-deposition of Pt nanoparticles. The formation of Pt shells was successfully performed on the SiO₂/PVP-Pt particles in the electroless metal plating process because Pt nuclei were generated by the reduction of H₂PtCl₆ and then further deposited on the Pt particle surfaces on the SiO₂/PVP-Pt particles.     

Relationship between structure and physical strength of silk fibroin nanofiber sheet depending on insolubilization treatment

Materials such as expanded polytetrafluoroethylene and glutaraldehyde‐fixed bovine pericardium are currently used for cardiac tissue regeneration. However, patches made from these materials remain permanently without being absorbed by the body and must be replaced overtime because of degeneration or lack of growth. To improve the long‐term outcomes for cardiac tissue regeneration, biocompatible and biodegradable materials must be used. In this study, we used two biocompatible polymers, silk fibroin (SF), which is biodegradable and segmented polyurethane, to prepare nonwoven sheets that were then insolubilized by water vapor or methanol treatment. The tensile stress increased significantly on adding segmented polyurethane to pure SF and the water vapor processed sheets showed higher extension on strain than the methanol‐processed sheets. The different insolubilization treatments also resulted in different SF structures. Our results show that it is possible to obtain the physical properties required for cardiac tissue repair patch by varying the insolubilization treatment. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45560.     

Difference in environmental degradability between poly(ethylene succinate) and poly(3-hydroxybutyrate)

A chemosynthetic aliphatic polyester, poly(ethylene succinate) (PESu), was degraded by a poly(3-hydroxybutyrate) (P(3HB)) depolymerase in vitro. While P(3HB) exhibited good biodegradability in all environments, PESu hardly underwent biodegradation in a marine environment. To understand the difference in environmental degradability between PESu and P(3HB), we investigated the distribution of P(3HB)- and PESu-degrading microbes in various environments. PESu-degrading microbes were never detected in marine environments. PESu-degrading bacteria isolated from various environments in this study belonged to the phyla Firmicutes and Proteobacteria. Most PESu-degrading bacterial isolates could not degrade P(3HB), suggesting that PESu was not degraded by P(3HB) depolymerase in actual environments. In addition, all bacterial isolates that were screened for P(3HB) degrading activity from various environments in this study did not degrade PESu, suggesting that PESu does not induce P(3HB) depolymerase in their bacteria and P(3HB)-degrading bacteria are not involved in biodegradation of PESu in actual environments. Taken together, these results could be related with the low biodegradability of PESu in marine environments.     

Controlled exposure chamber study of uptake and clearance of airborne polycyclic aromatic hydrocarbons by wheat grain

Polycyclic aromatic hydrocarbons (PAHs) can partition from the atmosphere into agricultural crops, contributing to exposure through the dietary pathway. In this study, controlled environmental chamber experiments were conducted to investigate the transfer of PAHs from air into wheat grain, which is a major food staple. A series of PAHs ranging in size from naphthalene to pyrene were maintained at elevated gas-phase concentrations in the chamber housing mature and dry wheat grain both on the plant and with the husk removed. The PAHs did not achieve equilibrium between the air and grain over the 6.5 month monitoring period used in this study. Therefore, PAH uptake under field conditions is expected to be kinetically limited. A clearance study conducted for the grain showed the half-life of clearance was approximately 20 days for all compounds studied. The results suggest that atmospheric contaminants that partition into grain may remain in the grain long enough to contribute to dietary exposure for humans. Mass transfer across the air/grain interface appeared to be limited by grain-side resistance. The grain may act as a multicompartment system with rapid exchange at the surface followed by slower transfer into the grain. A grain/air concentration relationship was derived for the uptake time that is relevant to field conditions.     

Four-point probe resistance measurements using PtIr-coated carbon nanotube tips

We performed four-terminal conductivity measurements on a CoSi2 nanowire (NW) at room temperature by using PtIr-coated carbon nanotube (CNT) tips in a four-tip scanning tunneling microscope. The physical stability and high aspect ratio of the CNT tips made it possible to reduce the probe spacing down to ca. 30 nm. The probe-spacing dependence of resistance showed diffusive transport even at 30 nm and no current leakage to the Si substrate.     

Faradaic impedance of dye-sensitized solar cells

Theoretical equations of the Faradaic impedance of the photoelectrode and the counter electrode of dye-sensitized solar cell (DSC) were derived. The Faradaic impedance is the frequency dependent resistance related to the time constants of elementary electrode processes like photoexcitation, electron transfer, charge transfer reaction and diffusion. The typical cell impedance spectrum describes the locus of three semicircles on the Nyquist plane. The locus of three semicircles is generally analyzed by using the equivalent circuit composed of charge transfer resistance (R_ct,1) and capacitance (C_dl,1) of counter electrode, charge transfer resistance (R_ct,2) and capacitance (C_dl,2) of photoelectrode, the finite diffusion impedance due to the diffusion of I₃⁻ on the counter electrode (Z_w), and total resistance of the substrate and solution (R_s). The physical meanings of R_ct,1 and R_ct,2 can be elucidated by the interpretations of Faradaic impedance derived in the present paper. The R_ct,1 is represented as the function of the potential-dependent rate constants of I₃⁻ reduction and I⁻ oxidation. On the other hand, the R_ct,2 is the function of the photoelectrode potential, the surface concentration of I₃⁻ and the potential-independent rate constant of the back electron transfer reaction. The theoretical expressions of the current-voltage (I-V) curve of the DSC can be also derived. In the present paper, the relations between the impedance and I-V curve of the DSC are discussed.     

Catalytic performance and characterization of Pt-Ni bimetallic catalysts for oxidative steam reforming of methane

Effects of methane oxygen mixture addition to steam reforming of methane and subsequent removal of the methane oxygen mixture from the oxidative steam reforming of methane on catalytic performance were investigated using monometallic Ni and Pt catalysts and two Pt-Ni bimetallic catalysts. Hysteresis with respect to the addition and removal of the methane oxygen mixture was observed clearly on a Pt-Ni bimetallic catalyst prepared by co-impregnation method and the Ni catalyst. In contrast, no hysteresis was observed for a Pt-Ni catalyst that was prepared by sequential impregnation method. Combined with characterization results obtained using EXAFS analysis and FTIR of CO adsorption, Pt-Ni catalyst was prepared by sequential impregnation is formed Pt-Ni alloy particles, where Pt atoms are segregated on the surface, enhances the reducibility of Ni drastically and this is related to the behavior without hysteresis.