Al-laminated film packaged organic radical battery for high-power applications

A 100-mAh class of aluminum-laminated film packaged organic radical battery with a poly(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl methacrylate) (PTMA) composite cathode and a graphite anode has been fabricated. Its total weight was 22 g and the thickness was 4.3 mm. Because PTMA comprised only 6.2% of the total cell weight, the energy density was considerably less than that of a lithium ion battery. However, the power density per active material weight was found to be better than that of lithium ion battery. The applications which require high-power capability rather than high-energy density, such as the sub-battery in electronic devices and motor drive assistance in electric vehicles, would be appropriate for organic radical batteries in the future.     

Development of Charge Sensitive Infrared Phototransistors for the Far-Infrared Wavelength

Ultra-highly-sensitive far-infrared detectors are developed for potential application to astronomy. The detectors exploit a novel mechanism called Charge Sensitive Infrared Phototransistors (CSIPs), in which an upper quantum well (QW) in GaAs/AlGaAs double QW structures is positively charged up by photo-excitation via inter-subband transition. This causes the conductance of the lower QW channel to increase. The device is effectively a phototransistor, in which the upper QW serves as a photo-sensitive gate to the source-drain channel provided by the lower QW. Resultant extraordinary high photoconductive gain makes CSIPs so sensitive as to detect single photons. CSIPs are well established in the mid-infrared ( \(\lambda \) = 12–20  \(\upmu \) m), achieving noise equivalent power around 1.9 \(\times \) 10 \(^{-19}\) W/Hz \(^{1/2}\) with a quantum efficiency of 7 %. CSIPs have been demonstrated to work in longer wavelengths up to 45  \(\upmu \) m, but the sensitivity was not as high as in the shorter wavelengths, probably due to lower quantum efficiency. Reported here is a remarkable improvement in the performance of longer wavelength CSIPs (45  \(\upmu \) m), achieved primarily by optimizing the doping concentration in the upper QW. This work indicates that longer wavelength CSIPs are promising detectors for the astronomical application.     

Residues of total mercury and methyl mercury in eel products

Fifty-two samples of broiled eels and broiled eel liver were analyzed for total mercury (total Hg) and methyl mercury. The mean concentrations of total Hg in broiled eels and broiled eel liver were 0.21 ppm and 0.10 ppm, respectively. Meanwhile, the mean concentrations of methyl mercury in broiled eels and broiled eel liver were 0.085 ppm and 0.039 ppm, respectively. The rate of methyl mercury to total Hg mainly ranged from 60 to 80% in broiled eels and from 35 to 65% in broiled eel liver. The total Hg concentrations of 2 samples of broiled eels and one sample of broiled eel liver exceeded the provisional regulation limit (0.4 ppm) of total Hg in fish in Japan. In these samples, the rates of methyl mercury to total Hg were lower than 20%. The muscles and the skin of broiled eels were measured separately. The ratios of skin to muscle concentration of total Hg and methyl mercury were mainly in the range from 1/10 to 1/4. The mean intakes of total Hg from broiled eels and broiled eel liver per individual were 24.6 microg and 3.1 microg, respectively. The mean intakes of methyl mercury from broiled eels and broiled eel liver per individual were 10.4 microg and 1.2 microg, respectively.     

Enzyme-catalyzed poly(3-hydroxybutyrate) synthesis from acetate with CoA recycling and NADPH regeneration in Vitro

We established a novel enzyme-catalyzed poly(3-hydroxybutyrate) [P(3HB)] synthesis system capable of recycling CoA on the basis of the P(3HB) biosynthetic pathway in Ralstonia eutropha. The system includes purified beta-ketothiolase (PhaA), NADPH-dependent acetoacetyl-CoA reductase (PhaB), PHA synthase (PhaC), acetyl-CoA synthetase (Acs) and glucose dehydrogenase (GDH). In this system, acetyl-CoA was synthesized from acetate and CoA by Acs and ATP, and then two molecules of acetyl-CoA were condensed by PhaA to synthesize acetoacetyl-CoA, which was converted to (R)-3-hydroxybutyryl-CoA (3HBCoA) by PhaB and NADPH. The 3HBCoA was polymerized by PhaC and converted to P(3HB). In this system, the CoA molecules that were released during the condensation and polymerization reactions catalyzed by PhaA and PhaC, respectively, were reused successfully for the synthesis of acetyl-CoA. In addition, NADPH, which was consumed in the reduction of acetoacetyl-CoA, was regenerated by the action of GDH. In this system, the yield of P(3HB) synthesized from acetate as the substrate was 5.6 mg in a 5-ml reaction mixture, and the weight-average molecular weight and polydispersity were 6.64 x 10(6) and 1.36, respectively. Furthermore, CoA was reused at least 26 times, and NADPH was also regenerated at least 26 times during 24 h of reaction.     

Methylene blue dye test for rapid qualitative detection of hydroxyl radicals formed in a Fenton's reaction aqueous solution

A new procedure, the methylene blue dye test, qualitatively indicates the presence of hydroxyl radicals through the immediate, distinct bleaching of methylene blue dye on a paper test strip. This method employs a simple procedure requiring inexpensive materials, without the addition of competitive probe chemicals that potentially can interfere with the reaction. A Fenton's reaction with an Fe2+:H2O2 molar ratio of 1:20 generated hydroxyl radicals in Milli-Q water. The presence and absence of hydroxyl radicals were determined prior to and following quenching of the Fenton's reaction with 10% sodium sulfite, respectively. Bleaching of methylene blue dye, due to the presence of hydroxyl radicals in a sample,was indicated by a discoloration from a dark blue color to an almost white color, concentrated at the point of application, with a dark blue outline. A lack of bleaching indicated the absence of hydroxyl radicals in the sample. The presence of hydroxyl radicals was verified by benzoic acid chemical probe experiments with thin-layer chromatography (TLC) and spectrophotometric wavelength scans. The presence of hydroxyl radicals was indirectly determined by detection of hydroxylated benzoic acids on TLC plates and a violet solution color with a peak absorbance at a wavelength close to 520 nm.     

Excellent flexural properties of aminimide-cured epoxy resin as a matrix for mica-dispersed polymer composites

The flexural behaviour of mica-dispersed epoxy resin composites has been examined. The flexural strength and flexural modulus have been determined as a function of the volume fraction of mica flakes (V _f) for both aminimide-cured epoxy resin matrix and a conventional epoxy resin reference matrix. On the basis of microscopic observation of fractured surfaces, the effect of improving the particle-matrix interface has been analysed using the modulus reduction factor (MRF) in a modified form. It is found that there is a steady increase in the flexural modulus with the volume fraction of mica flake for the aminimide-cured epoxy resin matrix. In contrast, the increase in flexural modulus levels off at a high content of filler for the reference samples. It is noteworthy that the intact mica flakes without surface treatment exhibit a substantial reinforcing effect on the flexural strength in the case of aminimide-cured epoxy resin composites. A further surprise is the difference among the curing agents used. The reference epoxy resins behave just like conventional matrix resins, exhibiting 30 to 40% reduction in the flexural strength when a small fraction of mica is added. These superior properties of the matrix resin for the composites are ascribed to the characteristics of aminimide-cured epoxy resins such as hardness, toughness, and excellent adhesivity.     

Harnessing Topology and Stereochemistry of Glycidylamine-Derived Lipid Nanoparticles for in Vivo mRNA Delivery to Immune Cells in Spleen and Their Application for Cancer Vaccination

mRNA lipid nanoparticles (LNPs) have reached an inflection point and are now paving the way for a new wave of precision therapies. The design of nonhepatocyte RNA delivery systems without targeting ligands, however, remains a challenge. It is reported that the development of ligand-free glycidylamine (GA) derivatives containing LNPs (GA-LNPs) that preferentially deliver mRNA to immune cells in the spleen. Notably, it is demonstrated that the stereochemistry of GA-lipids has a significant impact on their self-assembly and in vitro and in vivo RNA delivery efficiency and tropism. This impact is dependent on the monomeric structure of GA and number of stereogenic centers. Furthermore, the nonlinear topology of GA lipid derivatives induced a sevenfold improvement in mRNA delivery efficiency. The top-performing estriol-GA05-30 LNPs elicited strong antitumor activity in a therapeutic and prophylactic cancer model and are well tolerated in mice. These results highlight the significance of the chemistry of ionizable lipids for extrahepatic RNA delivery and indicated a promising direction for the development of next-generation mRNA immunotherapies.     

Biosynthetic Gene Cluster of Linaridin Peptides Contains Epimerase Gene

Salinipeptins belong to the type-A linaridin class of ribosomally synthesized and post-translationally modified peptides (RiPPs) comprising 22 amino acid residues with multiple D -amino acids. Although chirality of other type-A linaridins, such as grisemycin and cypemycin, has not been reported, the biosynthetic gene clusters of type-A linaridins have identical gene organization. Here, we report heterologous expression of grisemycin biosynthetic gene cluster (grm) and show that grisemycin contains multiple D -amino acids, similar to salinipeptins. The heterologous expression experiments also confirm the involvement of a novel peptide epimerase in grisemycin biosynthesis. Gene-deletion experiments indicate that grmL, a single gene with unknown function, is indispensable for grisemycin production. We also show that the presence of D -amino acids is likely a common feature of linaridin natural products by analyzing two other type-A linaridin clusters.