Chemical Modification of Novel Alkyne-Containing Polymers Obtained by Radical Polymerization of Conjugated Enynes

Summary Alkyne-containing polymers, obtained by the radical polymerization of 4-substituted conjugated enynes (CH₂=CH—CC—R: R—= Ph— and n-Bu—), were subjected to polymer reactions through their alkyne moieties. That is, the radical addition of a thiol fragment, the hydrosilylation, and reduction via the hydroalumination were carried out to give polymers bearing alkenyl sulfide, alkenylsilane, and alkene moieties, respectively.     

Development of novel Ru catalyst of preferential CO oxidation for residential polymer electrolyte fuel cell systems

CO preferential oxidation on a novel Ru catalyst greatly improved in activity and selectivity over a wide temperature range by the pre-treatment of H₂ reduction was characterized. The high performance was obtained by increasing the population of surface Ru(0) which improved O₂ activation at low temperatures. Methanation of CO on the catalyst can also contribute to the final CO clean-up from ca. 100 to <1 ppm at low temperatures where the influence of CO₂ methanation can be ignored.     

Cell-Based Odorant Sensor Array for Odor Discrimination Based on Insect Odorant Receptors

The olfactory system of living organisms can accurately discriminate numerous odors by recognizing the pattern of activation of several odorant receptors (ORs). Thus, development of an odorant sensor array based on multiple ORs presents the possibility of mimicking biological odor discrimination mechanisms. Recently, we developed novel odorant sensor elements with high sensitivity and selectivity based on insect OR-expressing Sf21 cells that respond to target odorants by displaying increased fluorescence intensity. Here we introduce the development of an odorant sensor array composed of several Sf21 cell lines expressing different ORs. In this study, an array pattern of four cell lines expressing Or13a, Or56a, BmOR1, and BmOR3 was successfully created using a patterned polydimethylsiloxane film template and cell-immobilizing reagents, termed biocompatible anchor for membrane (BAM). We demonstrated that BAM could create a clear pattern of Sf21 sensor cells without impacting their odorant-sensing performance. Our sensor array showed odorant-specific response patterns toward both odorant mixtures and single odorant stimuli, allowing us to visualize the presence of 1-octen-3-ol, geosmin, bombykol, and bombykal as an increased fluorescence intensity in the region of Or13a, Or56a, BmOR1, and BmOR3 cell lines, respectively. Therefore, we successfully developed a new methodology for creating a cell-based odorant sensor array that enables us to discriminate multiple target odorants. Our method might be expanded into the development of an odorant sensor capable of detecting a large range of environmental odorants that might become a promising tool used in various applications including the study of insect semiochemicals and food contamination.     

Electrochemical oxidation of ethylene glycol on Pt-based catalysts in alkaline solutions and quantitative analysis of intermediate products

Electrocatalytic activities of Pt/C, Pt-Ru/C, and Pt-Ni/C for the oxidation of ethylene glycol in a basic solution are evaluated by cyclic voltammetry and quasi-steady state polarization. Based on the results of Tafel slopes from quasi-steady state polarization, the catalytic activities for ethylene glycol oxidation are in the order of Pt-Ru/C > Pt-Ni/C > Pt/C. The analysis of intermediate products for ethylene glycol oxidation by higher performance liquid chromatograph (HPLC) demonstrates that the degree of ethylene glycol oxidation is dependent on catalysts. Pt-Ru/C shows the highest current densities for ethylene glycol oxidation, but shows lower fuel utilization. On the other hand, Pt-Ni/C shows higher ability to cleavage C–C bonds, but is suffered from catalyst poisoning. To improve the tolerance for catalyst poisoning, we construct a novel Pt-Ni-SnO₂/C catalyst, compare its catalytic activities, and evaluate the intermediates. Pt-Ni-SnO₂/C shows superior catalytic activities for ethylene glycol oxidation, resulting in the highest degree of complete electro-oxidation of ethylene glycol to CO₂.     

Structural aspects of the LCST phase behavior of poly(benzyl methacrylate) in room-temperature ionic liquid

The structure and lower critical solution temperature (LCST) phase behavior of well-defined poly(benzyl methacrylate) (PBnMA) solution using 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide, [C₂mim][NTf₂] ionic liquid (IL) as a solvent have been studied by dynamic light scattering (DLS) and small-angle neutron scattering (SANS) at various temperatures. The SANS profiles observed for fully deuterated IL ([C₂mim]-d₁₁[NTf₂]) containing PBnMA were kept practically unchanged in the temperature range between 298 and 363 K, while they suddenly changed at 363 K. This indicates that the LCST behavior of PBnMA-IL solution is a first-order phase transition, which is consistent with the DLS results. The SANS profiles below 363 K were well represented by the theoretical Debye scattering function with inter-molecular interaction and the radius of gyration, R_g was estimated to be almost constant, i.e., ∼45 Å. The SANS result obtained here was compared with those in aqueous PNIPAm solutions as a typical LCST system, and some differences between IL and aqueous solution systems are pointed out. It is found that thermodynamic quantities (ΔH_demix, ΔS_demix and ΔG_demix) from the homogeneous solution to the phase separation states strongly depend on the solvation of the PBnMA polymer by the IL ([C₂mim] cation and [NTf₂] anion). We propose an LCST phase separation mechanism in the polymer-IL solution.     

Protein adsorption on spark plasma sintered 2d‐, 3d‐ and lamellar type mesoporous silicate compacts

The preparation of lamellar type mesoporous silica (MPS) compact through the spark plasma sintering (SPS) and the adsorption/desorption of protein onto MPS compact are reported to be compared with those onto 2d‐hexagonal and 3d‐cubic type MPS compacts. A lamellar‐type MPS powder (MPS‐la) was prepared using triblock copolymer, PEO₅ PPO₆₈ PEO₅, and was compacted in a carbon die and heated at 500°C for 5 min under uniaxial pressure. The products are referred to as MPS‐la‐500. The MPS compacts keep the lamellar type mesoporous configuration. The adsorbed amount of protein onto MPS‐la‐500 was 100 mg/g, while that on MPS‐la was 130 mg/g, and the former decreased by 23%. However, its decreasing ratio of the protein adsorption on MPS‐la‐500 was less than those of 2d‐hexagonal and 3d‐cubic type MPS compacts, which were 73 and 34%, respectively. The released amount of protein into PBS solution from MPS‐la‐500, which was soaked in the protein solution for 48 h, increased with the soaking time, while those from 2d‐ and 3d‐type MPS compacts reached to plateau for 4 h of soaking. The lamellar type MPS compact was found to be easier to absorb and release proteins, which may be due to the large aperture of the mesoporous configuration.Inspec keywords: silicon compounds, polymer blends, mesoporous materials, adsorption, plasma materials processing, proteins, sintering, powders, desorption, compaction, molecular biophysicsOther keywords: lamellar‐type MPS powder, PEO5PPO68PEO5, MPS‐la‐500, protein adsorption, lamellar type MPS compact, 3d‐cubic type MPS compact, spark plasma sintering, 2d‐hexagonal type MPS compacts, lamellar type mesoporous silicate compacts, lamellar type mesoporous silica compact, desorption, triblock copolymer, uniaxial pressure, PBS solution, protein solution, soaking time, temperature 500.0 degC, time 5.0 min, time 48.0 hour, time 4.0 hour, SiO₂      

High-bit-rate low-power decision circuit using InP-InGaAs HBT technology

We have successfully designed and fabricated a high-bit-rate low-power decision circuit using InP-InGaAs heterojunction bipolar transistors (HBTs). Its main design feature is the use of a novel master-slave D-type flip-flop (MS-DFF) as the decision circuit core to boost the operating speed. We achieved error-free operation at a data rate of up to 60 Gb/s using an undoped-emitter InP-InGaAs HBT with a cutoff frequency f/sub T/ of approximately 150 GHz and a maximum oscillation frequency f/sub max/ of approximately 200 GHz. Our decision circuit operates approximately 15% faster than one with a conventional MS-DFF core. We also achieved 90-Gb/s operation with low power consumption of 0.5 W using an InP-InGaAs DHBT exhibiting f/sub T/ and f/sub max/ of 232 and 360 GHz, respectively. These results demonstrate that InP-based HBTs and our novel MS-DFF are attractive for making ultrahigh-performance ICs for future optical communications systems operating at bit rates of 100 Gb/s or more.     

The fabrication method of unsubstituted planar phthalocyanine thin films by a spin-coating technique

We have successfully obtained spin-coated films of unsubstituted planar phthalocyanines (free-base and copper phthalocyanine) from trifluoroacetic acid and chlorobenzene mixed solutions for the first time. The pre-annealed films did not consist of pure phthalocyanines; these films contained the solvent molecules. However, the residual solvent molecules could be removed by annealing at 425 K for 2 h in vacuum. This technique is useful for fabricating unsubstituted planar phthalocyanine thin films.     

An exact method for solving logical loops in reliability analysis

This paper presents an exact method for solving logical loops in reliability analysis. The systems that include logical loops are usually described by simultaneous Boolean equations. First, present a basic rule of solving simultaneous Boolean equations. Next, show the analysis procedures for three-component system with external supports. Third, more detailed discussions are given for the establishment of logical loop relation. Finally, take up two typical structures which include more than one logical loop. Their analysis results and corresponding GO-FLOW charts are given. The proposed analytical method is applicable to loop structures that can be described by simultaneous Boolean equations, and it is very useful in evaluating the reliability of complex engineering systems.