Unlocking the chemical environment of nitrogen in perovskite-type oxides.

Nitrogen (N) doping of perovskite-type oxides is an effective method for enhancing their photocatalytic performance. Quantitative and qualitative analyses of the doped N species are essential for a deeper understanding of the catalytic activity enhancement mechanism. However, examining the N environment in perovskite-type oxides, particularly in the bulk, using conventional analytical techniques, such as X-ray photoelectron spectroscopy (XPS), is challenging. In this study, we propose a new analytical technique, advanced temperature-programmed desorption (TPD) up to 1600 °C, to complement the conventional methods. TPD can quantify all N species in bulk oxides. Moreover, it facilitates chemical speciation of N environments, such as substitutional and interstitial N species. This is verified by XPS, CHN elemental analysis, X-ray absorption spectroscopy, and in situ diffuse reflectance infrared Fourier-transform spectroscopy. This study demonstrates the feasibility of advanced TPD as a new analytical method that offers comprehensive information on the N species within N-doped oxide materials at the bulk level.

Sealing ability of various endodontic sealers with or without ethylenediaminetetraacetic acid (EDTA) treatment on bovine root canal.

This study investigated the wettability and consistency of various endodontic sealers, both inorganic and organic, and evaluated their sealing ability of root canals using the single-cone obturation technique, with and without ethylenediaminetetraacetic acid (EDTA) treatment. Bovine root canals were endodontically prepared and filled in preparation for the dye penetration test with toluidine blue solution. All sealers exhibited contact angles similar to or lower than dentin and displayed superior consistency. Among the sealers, organic sealers used without EDTA treatment showed reduced dye penetration compared to inorganic sealers. However, some inorganic and organic sealers showed dye penetration in the sealer and dentin of root canals subjected to EDTA treatment. In conclusion, the single-cone obturation technique, combined with these endodontic sealers, achieved close contact with root canal dentin due to their wettability and consistency. However, the sealing ability of certain sealers was influenced by EDTA treatment.

Effects of different bonding systems with various polymerization modes and root canal region on the bond strength of core build-up resin composite.

Purpose The aim of this study was to clarify the effects of different bonding systems (BSs) with various polymerization modes and root canal regions on the bond strength of core build-up resin composite to dentin.Methods Post cavities were prepared in the roots of 54 bovine teeth. Three types of BS with various polymerization modes (light, chemical, and dual-cure) were applied to the walls of the cavities, which were subsequently filled with core build-up resin composite, and stored in 37°C water for 7 days. Each tooth was then sectioned perpendicular to the long axis of the tooth into 9-disk from the coronal to the apical side. Bond strengths were measured on two-thirds of the disks, while dye penetration was examined in the remaining third.Results Statistical analysis revealed significant differences between the bond strengths of BSs with different polymerization modes, indicating chemical-cured BS had higher bond strength than light-cured BS. The chemical-cured BS group showed cohesive failure in both resin composite and dentin regardless of the root canal region, while adhesive failure was observed in the coronal region for dual-cured BS and in the apical region for light-cured BS. Dye penetration was significantly more at the bonding interface at the apical region of the light-cured BS.Conclusions Chemical-cured BS displayed a greater bond strength than light-cured BS. Cohesive failure was observed in both core build-up resin and dentin, indicating that the integration of tooth structure with resin composite was effective for retaining the resin core and sealing the root canal.

Effects of indole and indoxyl on the intracellular oxidation level and phagocytic activity of differentiated HL-60 human macrophage cells.

Indoxyl, a derivative of indole originating from tryptophan, may undergo phase-II sulfate-conjugation pathway, thereby forming indoxyl sulfate (IS) in vivo. We previously reported that IS, a well-known uremic toxin, can increase the intracellular oxidation level and decrease the phagocytic activity in a differentiated HL-60 human macrophage cell model. Using the same cell model, the current study aimed to investigate whether indole and indoxyl (the metabolic precursors of indoxyl and IS, respectively) may cause macrophage immune dysfunction. Results obtained indicated that intracellular oxidation level and cytotoxicity markedly increased upon treatment with indole and indoxyl, in comparison with IS. Incubation of the cells with indole and indoxyl also resulted in attenuated phagocytic activity. Human serum albumin (HSA)-binding assay confirmed that tryptophan and IS, but not indole and indoxyl, could selectively bind to the site II in HSA. Collectively, the results indicated that indole and indoxyl may strongly down-regulate the phagocytic immune function of macrophages, whereas IS, formed upon sulfate conjugation of indoxyl, may exhibit enhanced HSA-binding capability, thereby reducing the adverse effects of indoxyl.

Investigation of the effects of indoxyl sulfate, a uremic toxin, on the intracellular oxidation level and phagocytic activity using an HL-60-differentiated human macrophage cell model.

Indoxyl sulfate (IS), a uremic toxin, is a sulfate-conjugated metabolite originated from tryptophan. Accumulating uremic toxins may worsen renal diseases and further complicate related disorders including impaired immune functions under oxidative stress conditions. However, it has remained unclear whether or not IS can directly cause the cellular immune dysfunction. We investigated the effects of IS on the intracellular oxidation level and phagocytic activity in a HL-60-differantiated human macrophage cell model. Incubation of the cells in the presence of IS resulted in increasing intracellular oxidation level and decreasing phagocytic activity. In addition to inhibitors for NADH oxidase (NOX), organic anion transporting polypeptide2B1 (OATP2B1), protein kinase C (PKC), and phosphoinositide 3-kinase (PI3K), a representative antioxidant Trolox, was also shown to significantly relieve the IS-induced oxidation and restore weakened phagocytosis. Collectively, IS may directly down-regulate the phagocytic immune function of macrophages through the oxidation mechanisms including OATP2B1, PKC, PI3K, and NOX pathways. Abbreviations: CKD: Chronic kidney disease; IS: Indoxyl sulfate; ROS: Reactive oxygen species; NOX: NADH oxidase; OATP2B1: Organic anion transporting polypeptide2B1; PKC: Protein kinase C; PI3K: Phosphoinositide 3-kinase; 2-APT: 2-acetylphenothiazine.

Novel Organic-Inorganic Perovskite Compounds Having Phosphonium Groups.

Organic-inorganic perovskites are composed of organic cations and [PbX6]4- octahedra, and the properties change depending on the type of organic cations. To identify the effect of organic cations and control the properties of the perovskite, thin films were prepared using quaternary alkylammonium and quaternary alkylphosphonium cations, which have big steric effects. A big steric effect can generate the distortion of [PbX6]4- octahedra leading to changes in properties. A thin film of a Pb-based organic-inorganic perovskite having quaternary alkylphosphonium cations was prepared for the first time. An exciton absorption was observed at a lower wavelength than other perovskites prepared from primary and quaternary ammonium salts. The perovskite with phosphonium groups was thermally stable compared with ammonium groups.

Orexin A enhances food intake in bullfrog larvae.

Orexin is a potent orexigenic peptide implicated in appetite regulation in rodents. However, except for teleost fish, the involvement of orexin in the regulation of feeding in non-mammalian vertebrates has not been well studied. Anuran amphibian larvae feed and grow during the pre- and prometamorphic stages. Therefore, orexigenic factors seem to play important roles in growing larvae. Indeed, our recent studies have demonstrated that neuropeptide Y and ghrelin exert orexigenic actions in bullfrog larvae during the prometamorphic stages. In this study, we examined the effect of intracerebroventricular (ICV) administration of synthetic orexin A on food intake in bullfrog larvae at the prometamorphic stages. Food intake was significantly increased by ICV administration of orexin A (at 6 pmol/g BW) during a 15-min observation period. The orexigenic action of orexin A at 6 pmol/g BW was blocked by treatment with an orexin receptor antagonist, SB334867, at 60 pmol/g BW. These results indicate that orexin A acts as an orexigenic factor in bullfrog larvae.

Stimulatory effect of ghrelin on food intake in bullfrog larvae.

Ghrelin is a potent orexigenic peptide implicated in appetite regulation in rodents. However, except for teleost fish, the involvement of ghrelin in the regulation of feeding in non-mammalian vertebrates has not been well studied. Anuran amphibian larvae feed and grow during the pre- and prometamorphic stages, but, thereafter they stop feeding as the metamorphic climax approaches. Therefore, orexigenic factors seem to play important roles in growing larvae. In the present study, we examined the effect of intraperitoneal (IP) or intracerebroventricular (ICV) administration of synthetic bullfrog ghrelin (n-octanoylated 28-amino acid form) on food intake in larvae at the prometamorphic stages. Cumulative food intake was significantly increased by IP (8 and 16pmol/g body weight (BW)) or ICV (0.5 and 1pmol/g BW) administration of ghrelin during a 15-min observation period. The orexigenic action of ghrelin at 8pmol/g BW (IP) or at 0.5pmol/g BW (ICV) was blocked by treatment with a growth hormone secretagogue-receptor antagonist, [D-Lys(3)]GHRP-6 at 80pmol/g BW (IP) or at 5pmol/g BW (ICV). We then investigated the effect of feeding status on expression levels of the ghrelin transcript in the hypothalamus and gastrointestinal tract. Ghrelin mRNA levels in both were decreased 15 and 60min after feeding. These results indicate that ghrelin acts as an orexigenic factor in bullfrog larvae.

Effect of neuropeptide Y on food intake in bullfrog larvae.

Neuropeptide Y (NPY) is a potent orexigenic neuropeptide implicated in appetite regulation in mammals. However, except for teleost fish such as the goldfish and zebrafish, the involvement of NPY in the regulation of feeding in non-mammalian vertebrates has not been well studied. Anuran amphibian larvae feed and grow during the pre- and pro-metamorphic stages, but, thereafter they stop feeding as the metamorphic climax approaches. Therefore, orexigenic factors seem to play important roles in pre- and pro-metamorphic larvae. We investigated the role of NPY in food intake using bullfrog larvae including pre- and pro-metamorphic stages, and examined the effect of feeding status on the expression level of the NPY transcript in the hypothalamus. NPY mRNA levels in hypothalamus specimens obtained from larvae that had been fasted for 3 days were higher than those in larvae that had been fed normally. We then investigated the effect of intracerebroventricular (ICV) administration of NPY on food intake in the larvae. Cumulative food intake was significantly increased by ICV administration of NPY (5 and 10 pmol/g body weight, BW) during a 15-min observation period. The NPY-induced orexigenic action (10 pmol/g BW) was blocked by treatment with a NPY Y1 receptor antagonist, BIBP-3226 (100 pmol/g BW). These results indicate that NPY acts as an orexigenic factor in bullfrog larvae.