Flow injection analysis combined with a hydrothermal flow reactor: application to kinetic determination of trace amounts of iridium using a water-soluble porphyrin

A new type of flow injection analysis (FIA) system combined with an extremely high temperature reactor, namely hydrothermal flow injection analysis (HT-FIA), has been successfully constructed for the first time. Fundamental characteristics of HT-FIA system, such as limit temperature, pressure, and flow rate, were examined as an analytical tool. To demonstrate the potential of HT-FIA, the catalytic activity of Ir(IV) for the degradation of a water-soluble porphyrin, 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid (TPPS), was applied for the determination of trace amounts of Ir(IV). Although the indicator reaction is very slow at room temperature, HT-FIA system enables to accelerate the reaction. A linear calibration curve was acquired at 10⁻⁸ M level of Ir(IV) and the interferences of platinum group metal ions were examined. The detection limit of Ir(IV) was 5.8 × 10⁻⁹ M and a fairly high-throughput analysis, of which more than 30 samples can be analyzed within 80 min, was achieved.     

Ukulactones A and B, new NADH-fumarate reductase inhibitors produced by Penicillium sp. FKI-3389

Screening for NADH-fumarate reductase inhibitors led to the isolation of the new polyketide compounds, ukulactones A and B (1 and 2, Fig. 1) from a culture broth of Penicillium sp. FKI-3389. The structure of ukulactone A was elucidated as a methylated derivative of prugosene A1, which was produced by Penicillium rugulosum and NOESY experiment revealed ukulactone B was a stereoisomer of ukulactone A. Ukulactone A showed potent inhibitory activity against NADH-fumarate reductase of the roundworm Ascaris suum in vitro.     

Rational design of photoconvertible and biphotochromic fluorescent proteins for advanced microscopy applications

Advanced fluorescence imaging, including subdiffraction microscopy, relies on fluorophores with controllable emission properties. Chief among these fluorophores are the photoactivatable fluorescent proteins capable of reversible on/off photoswitching or irreversible green-to-red photoconversion. IrisFP was recently reported as the first fluorescent protein combining these two types of phototransformations. The introduction of this protein resulted in new applications such as super-resolution pulse-chase imaging. However, the spectroscopic properties of IrisFP are far from being optimal and its tetrameric organization complicates its use as a fusion tag. Here, we demonstrate how four-state optical highlighting can be rationally introduced into photoconvertible fluorescent proteins and develop and characterize a new set of such enhanced optical highlighters derived from mEosFP and Dendra2. We present in particular NijiFP, a promising new fluorescent protein with photoconvertible and biphotochromic properties that make it ideal for advanced fluorescence-based imaging applications.     

Effect of Cement on Properties of Inverted Emulsions and Polymers from Vinyl Monomers with Acid Anhydride-Adducted Polypropylene Glycol

Abstract

Adduct polymer (PPGMA) prepared from polypropylene glycol and maleic anhydride was found to give stable inverted emulsions when mixtures of cement, water, and vinyl monomers were vigorously stirred in the presence of PPGMA. In this case, the carboxyl groups of PPGMA were neutralized with metal ions generated from the cement into neutralized PPGMA which acts as an effective W/O type emulsifier. The inverted emulsions containing cement gave a new type of polymer-cement composites by polymerization of the vinyl monomers and also by hardening of the cement. Water-free composites were easily obtained by removing evaporative water. The effect of cement on the physical properties of the water-free composites was remarkable. Further, the use of mixed fillers of cement and Al(OH)₃ was found to improve the flame-retardant properties of the composites; however, increasing the Al(OH)₃ content in the fillers resulted in a decrease in the physical properties. Generally, the composites have improved resistance to acid media in which the usual foamed hydrated cement is eroded.     

Synthesis of Polymers by Using Divalent Metal Salts of Mono(hydroxyethyl) Phthalate: Metal-Containing Three-Dimensional Polyesters from Metal Salts,Pyromellitic Dianhydride,and Epoxides

Syntheses of metal-containing three-dimensional polyesters were investigated by the reactions of divalent metal salts of mono(hydroxyethyl) phthalate-pyromellitic dianhydride-epoxide in DMF at 90° C. The metal carboxylate groups of these metal salts catalyzed the reactions. Systems with low metal salt content gelled during reaction. The yield of the products obtained by precipitating or washing with water increased with decreasing metal salt content in the feed. The products were metal-containing, three-dimensional polyesters containing ionic links; they were slightly yellow powdery materials. Hydroxyl values of the products were much higher than the values of acidity. Inherent viscosities (in DMF at 30° C) of the products obtained from the systems which did not gel were low, ranging from 0.031 to 0.083. The thermal stability of the products showed a tendency to increase with decreasing metal salt content in the feed.     

Water-Containing Cured Resin from Inverted Emulsion of Unsaturated Polyester Based on Divalent Metal Salt of Mono(hydroxyethyl)phthalate

Inverted emulsion, i.e., water-in-oil (W/O) type emulsion, was prepared from styrene solution of unsaturated polyester obtained from Mg salt of mono(hydroxyethyl)phthalate, ethylene glycol (EG), maleic anhydride (MA), phthalic anhydride (PA), and propylene oxide (PO). The inverted emulsion was much more stable than that of blank polyester obtained from EG, MA, PA, and PO, and further than the usual inverted emulsion prepared by treating styrene solution of commercial unsaturated polyester with triethanolamine. By polymerization, the inverted emulsion was transformed to a white solid which was dry to the touch. The water-containing cured resin obtained showed considerably higher physical and other properties than those of commercial unsaturated polyester.     

Interfacial Polycondensation in Aqueous and Non-Aqueous Systems

Abstract

Interfacial polycondensation in aqueous and non-aqueous systems has been investigated in order to synthesize various polyamides having functional groups. Rigid aromatic polyamides having pyridine moieties (PPy) were synthesized by interfacial polycondensation using an aqueous system and the solution properties of PPy in concentrated sulfuric acid were investigated in terms of solution viscosity and lyotropic behavior. Interfacial polycondensation in a non-aqueous system using two immiscible solvents was found to be useful for the synthesis of aromatic polyesters and copolyesters.     

An explicit formula of Atkinson type for the product of the Riemann zeta-function and a Dirichlet polynomial

We prove an explicit formula of Atkinson type for the error term in the asymptotic formula for the mean square of the product of the Riemann zeta-function and a Dirichlet polynomial. To deal with the case when coefficients of the Dirichlet polynomial are complex, we apply the idea of the first author in his study on mean values of Dirichlet L-functions.     

Flame structure and flame spread rate over a solid fuel in partially premixed atmospheres

We have investigated the downward flame spread over a thin solid fuel. Hydrogen, methane, or propane, included in the gaseous product of pyrolysis reaction, is added in the ambient air. The fuel concentration is kept below the lean flammability limit to observe the partially premixing effect. Both experimental and numerical studies have been conducted. Results show that, in partially premixed atmospheres, both blue flame and luminous flame regions are enlarged, and the flame spread rate is increased. Based on the flame index, a so-called triple flame is observed. The heat release rate ahead of the original diffusion flame is increased by adding the fuel, and its profile is moved upstream. Here, we focus on the heat input by adding the fuel in the opposed air, which could be a direct factor to intensify the combustion reaction. The dependence of the flame spread rate on the heat input is almost the same for methane and propane/air mixtures, but larger effect is observed for hydrogen/air mixture. Since the deficient reactant in lean mixture is fuel, the larger effect of hydrogen could be explained based on the Lewis number consideration. That is, the combustion is surely intensified for all cases, but this effect is larger for lean hydrogen/air mixture (Le < 1), because more fuel diffuses toward the lean premixed flame ahead of the original diffusion flame. Resultantly, the pyrolysis reaction is promoted to support the higher flame spread rate.     

Nonlinear ship waves and computational fluid dynamics

Research works undertaken in the first author’s laboratory at the University of Tokyo over the past 30 years are highlighted. Finding of the occurrence of nonlinear waves (named Free-Surface Shock Waves) in the vicinity of a ship advancing at constant speed provided the start-line for the progress of innovative technologies in the ship hull-form design. Based on these findings, a multitude of the Computational Fluid Dynamic (CFD) techniques have been developed over this period, and are highlighted in this paper. The TUMMAC code has been developed for wave problems, based on a rectangular grid system, while the WISDAM code treats both wave and viscous flow problems in the framework of a boundary-fitted grid system. These two techniques are able to cope with almost all fluid dynamical problems relating to ships, including the resistance, ship’s motion and ride-comfort issues. Consequently, the two codes have contributed significantly to the progress in the technology of ship design, and now form an integral part of the ship-designing process.