Search

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)

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.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.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.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.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.

Exploring the simple fabrication process to prepare CNC@HAp for biological tissues is still a challenging subject considering the wide applications of the composites for bio tissues. In this work, aiming for the fabrication of CNC@HAp composites via a simple and environment-friendly process and materials, we propose the neutralization titration in the presence of CNCs in the suspension. Core–shell structured composite of cellulose nanocrystal (CNC) and hydroxyapatite (HAp) (CNC@HAp) was successfully synthesized via simple aqueous neutralization titration. The method studied successfully hybridizes CNCs with a certain amount of HAps and easily controls the coating amounts of HAps from 9 wt% to 17 wt%. In particular, CNC@HAp pellets were easily prepared by simple compression molding from the powder of hybridized CNCs and HAps and the pellets showed high mechanical strength of over 500 N with a low strain of less than 5%. Both the process and the product of the study were environmental-friendly, no toxicity, simple and pure therefore the CNC@HAp can be easily applied to tissue engineering and medical purposes.

Polymer electrolyte fuel cells (PEFC) are expected as next energy generation systems, and their performance is strongly dependent upon the polymer electrolyte membrane (PEM). We have suggested a ne...

Proton conduction in the current polymer electrolyte membrane depends on water molecules, which necessitates high-humidity environments. On the contrary, proton conduction in low-humidity environments has been required for expanding operation conditions of polymer electrolyte fuel cells. Recently, ionic liquids (ILs) have been focused on novel proton conductive materials, however, the ILs were hard to fabricate the self-standing membrane owing to their fluidity. In this paper, we have developed composite materials composed of ILs and inorganic nanoparticles by coating ILs as polymer states (PILs) on the surface of nanoparticles. Notably, this material has obtained a powder form, and we have succeeded in suppressing the fluidity of ILs. The PILs-coated nanoparticles have achieved good proton conductivity over 10−2 S cm−1 at 95% RH, also indicated over 10−4 S cm−1 under 60% RH. In addition, we have clarified the relationship between the thickness of PILs and proton conductivities.

Polymer electrolyte membrane (PEM) fuel cells have challenges in operation under low-humidity conditions caused by a proton conduction mechanism dependent on water. We focused on polymeric ionic liquids (PILs), which are promising for high proton conductivity under a wide range of environments because they have the characteristics of polymer electrolyte liquids. However, it is difficult to fabricate self-standing membranes of PILs due to their high hygroscopicity and fluidity. In this paper, to inhibit the fluidity of the PIL in developing a self-standing PEM, the hydrophobic chain segment of styrene is inserted between the PILs of poly(vinylphosphonic acid/1-propylimidazole) (P(VPA/1PIm)) by RAFT polymerization. The synthesized sample of P(VPA/1PIm)-block-polystyrene is potentially applicable to PEM materials because it was obtained in powder state, having a high heat resistance of up to 300 °C, and exhibiting a proton-conducting property under a wide range of environments.

Viologens with linear alkyl chains from propyl to hexyl were synthesized to complete a series from methyl to octyl viologens, together with commercial samples, to study formation of their co-crystals with 1,3-bis(dicyanomethylidene)indan anion (TCNIH-). Co-crystals in a (viologen)(TCNIH)2 composition were obtained for all the viologens without inclusion of any other ions or solvent molecule. A border was clearly found between pentyl and hexyl for the evolution of charge transfer (CT) band in the absorption spectrum for electron transfer from TCNIH- donor to viologen acceptor. Strong coulombic interaction for close packing of co-crystals obviously contributes to the evolution of CT, although it is suppressed when the side chain is bulkier than hexyl to weaken the donor/acceptor interaction, as supported by drastic decrease of melting point and drastic increase of the largest crystal lattice spacing, found by DSC and PXRD, respectively. An exception was the salt with propyl viologen which did not show the CT band, in spite of the relatively strong donor/acceptor interaction.

Organic–inorganic hybrid lead halide perovskite nanocrystals (PeNCs) have received great attention as a light source for perovskite LEDs (PeLEDs) owing to the superior optical properties. However, PeNCs typically use octylamine (OAm) as capping ligands which have insulating properties. Exploring a desirable short alkylamine instead of OAm is required for the improvement of PeLEDs. Here, as one of the strategies to solve this issue, the effects of alkylamine chain length for optical properties of PeNCs and PeLED characteristics are investigated. Pentylamine is an optimal short alkylamine and precipitate luminescent PeNCs with high PLQY values of 90%. Importantly, pentylamine maintains a relatively high PLQY of 48% after spin-coating, due to the durability pentylamine has to ethyl acetate as a washing solvent. PeNCs capped with pentylamine also demonstrate an external quantum efficiency of over 1% with luminance of over 2000 cd cm−2, indicating that pentylamine has the potential to overcome the insulator properties of PeNC thin film.

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.

[Introduction] Organic charge transfer crystals (CTCs) can be interesting candidates as light absorbers of solar cells to eliminate large voltage loss inherent in dye-sensitized and bulk hetero junction types, in which carrier generation relies on the energy cascades. We have synthesized novel CTCs by forming salts between 1,3-bis(dicyanomethylidene)indan anion (TCNIH-) as a donor and viologen cations as acceptors, namely, N,N’-alkyl substituted 4,4’-bipyridiniums (Fig. 1, methyl = MV2+, ethyl = EV2+, heptyl = HV2+ and octyl = OV2+). [Experimental] Mixed salts of TCNIH- and viologens were obtained by slowly evaporating solvent at room temperature from their 2 : 1 mixed solution in ethanol. While their crystal structures were examined on powder samples and single crystals, their optical properties were studied by measuring UV-Vis and PL spectra between 77 and 298 K on a Horiba Fluorolog-3 equipped with a liq. N2 cryostat. [Results and Discussion] Colorless TCNIH2 turns into deep blue in ethanol due to deprotonation from its methylene carbon to become TCNIH- anion (Fig. 1). While its salt with Na+ was purplish black, having similar absorption features as the solution of TCNIH- with its onset around 800 nm, co-crystals with MV2+ and EV2+ were black with metallic shine to exhibit extended CT absorption in NIR up to ca. 1,000 nm (Fig. 2). On the other hand, those with HV2+ and OV2+ are quite similar to the Na+ salt with only small extension. All of the mixed crystals exhibited XRD patterns different from those of original TCNIH2 and viologen halides, indicating formation of their salts. Single crystal XRD structural analysis performed on large grains revealed monoclinic structure for MV2+ salt, while triclinic for the rest, in which TCNIH- and viologen cations are alternately stacked in 2 : 1 ratio. On increasing the length of the alkyl substituents, expansion and distortion of lattice occurs as seen from their lattice constants summarized in Table 1. The close packing of TCNIH- and MV2+/EV2+ by coulombic interaction obviously contributed to the enhancement of CT, whereas bulky HV2+ and OV2+ prohibited their intimate interaction. PL spectra were measured for the salts (Fig. 3). The Na+ salt indicates a spectrum very similar to that of the TCNIH- solution with not much enhancement and peak shift between 77 and 298 K, indicating emission from the exciton localized in a single TCNIH-. The salts with MV2+ and EV2+ exhibit broad emissions in the NIR range, which are greatly enhanced and resolved into two peaks at 77 K. Exciton-phonon coupling to delocalize exciton within CTCs explains these observations. PL spectra of HV2+ and OV2+ salts are unique, with their energy clearly smaller than that of the Na+ salt, despite of their very similar energy of excitation. Also, clear enhancement and resolution into two peaks at 77 K in case of OV2+ salt suggest relaxation of the TCNIH- localized exciton down to the CT states within these crystals. Acknowledgment The present work was supported by Program for Advancing Strategic International Networks to Accelerate the Circulation of Talented Researchers, “Advanced Next Generation Energy Leadership (R2601, FY2014-2016)” of Japan Society for the Promotion of Science (JSPS). Figure 1

A cyclic glucosyl ceramide (GlcCer) acceptor has been developed as a versatile building block for the synthesis of complex ganglioside. A macrocyclic GlcCer acceptor, which was the product of intramolecular glycosylation between glucose and ceramide, exhibited high reactivity during the coupling reactions with a variety of complex oligosaccharyl donors, thereby furnishing the corresponding ganglioside frameworks in high yields.