Proton conductivity dependence on the surface polymer thickness of core-shell type nanoparticles in a proton exchange membrane.

The proton exchange membrane (PEM) is the main component that determines the performance of polymer electrolyte fuel cells. The construction of proton-conduction channels capable of fast proton conduction is an important topic in PEM research. In this study, we have developed poly(vinylphosphonic acid)-block-polystyrene (PVPA-b-PS)-coated core-shell type silica nanoparticles prepared by in situ polymerization and a core-shell type nanoparticle-filled PEM. In this system, two-dimensional (2D) proton-conduction channels have been constructed between PVPA and the surface of silica nanoparticles, and three-dimensional proton-conduction channels were constructed by connecting these 2D channels by filling with the core-shell type nanoparticles. The proton conductivities and activation energies of pelletized PVPA-coated core-shell type nanoparticles increased depending on the coated PVPA thickness. Additionally, pelletized PVPA-b-PS-coated silica nanoparticles showed a good proton conductivity of 1.3 × 10-2 S cm-1 at 80 °C and 95% RH. Also, the membrane state achieved 1.8 × 10-4 S cm-1 in a similar temperature and humidity environment. Although these proton conductivities were lower than those of PVPA, they have advantages such as low activation energy for proton conduction, suppression of swelling due to water absorption, and the ability to handle samples in powder form. Moreover, by using PS simultaneously, we succeeded in improving the stability of proton conductivity against changes in the temperature and humidity environment. Therefore, we have demonstrated a highly durable, tough but still enough high proton conductive material by polymer coating onto the surface of nanoparticles and also succeeded in constructing proton-conduction channels through the easy integration of core-shell type nanoparticles.

Impaired production of skin barrier lipid acylceramides and abnormal localization of PNPLA1 due to ichthyosis-causing mutations in PNPLA1.

BACKGROUND: PNPLA1 is a causative gene of autosomal recessive congenital ichthyosis. The transacylase PNPLA1 produces ω-O-acylceramides (acylceramides), lipids essential for the skin barrier function, by catalyzing the transfer of a linoleic acid from triglycerides to ω-hydroxyceramides. OBJECTIVE: We aimed to validate the involvement of PNPLA1 mutations found in ichthyosis patients in the pathogenesis and elucidate the correlation between the effects of these mutations on acylceramide-producing activity and ichthyosis pathology. METHODS: Acylceramide-producing activity of PNPLA1 mutants was investigated using a cell-based assay system, in which wild-type PNPLA1 or each PNPLA1 mutant was co-overexpressed with the enzymes involved in acylceramide synthesis. The effect of each mutation on the ABHD5-dependent lipid droplet localization of PNPLA1 was examined through indirect immunofluorescence microscopy. RESULTS: Of 16 PNPLA1 missense mutations, 15 mutations, except the C216R mutation, resulted in a complete loss of acylceramide-producing activity, while the C216R mutation weakly affected this activity. Intracellular localization of mutants with no activity varied among mutants. Two mutants (S19L and D172N) localized in lipid droplets, and eight mutants (S53L, S53W, A59V, T125N, D129E, R166C, P234S, and P235L) partially localized there. Five mutants (A34P, A34T, S53P, K141E, and P163L) localized throughout the cytosol. CONCLUSION: The PNPLA1 missense mutations examined in this study are responsible for ichthyosis pathology. The weak effect of C216R mutation on acylceramide-producing activity correlates with the mild symptoms of the ichthyosis patient. Sixteen PNPLA1 mutants were classified into four groups based on their acylceramide-producing activity and localization.

Novel Filler-Filled-Type Polymer Electrolyte Membrane for PEFC Employing Poly(vinylphosphonic acid)-b-polystyrene-Coated Cellulose Nanocrystals as a Filler.

Low-acidity polymer electrolyte membranes are essential to polymer electrolyte fuel cells (PEFCs) and water electrolysis systems, both of which are expected to be next-generation energy and hydrogen sources. We developed a new type of high-performance polymer electrolyte membrane (PEM) in which the core particles are precisely electrolyte polymer coated and filled into binder resin. Cellulose nanocrystals (CNCs), which have attracted attention as light, rigid, and sustainable materials, were selected as the core material for the filler. The CNC surface was coated with a new block copolymer containing a proton conductive polymer of poly(vinylphosphonic acid) (PVPA) and a hydrophobic polymer of polystyrene (PS) using RAFT polymerization with particles (PwP) we developed. The pelletized fillers and the filler-filled polycarbonate membranes achieved proton conductivities of over 10-2 S/cm with lower activation energies and much weaker acidity than the Nafion membrane.

Design and synthesis of a novel ganglioside ligand for influenza A viruses.

A novel ganglioside bearing Neua2-3Gal and Neua2-6Gal structures as distal sequences was designed as a ligand for influenza A viruses. The efficient synthesis of the designed ganglioside was accomplished by employing the cassette coupling approach as a key reaction, which was executed between the non-reducing end of the oligosaccharide and the cyclic glucosylceramide moiety. Examination of its binding activity to influenza A viruses revealed that the new ligand is recognized by Neua2-3 and 2-6 type viruses.