Fabrication of Highly Crystalline SnNb₂O₆ Shell with a Visible-Light Response on a NaNbO₃ Nanowire Core

A visible-light-absorbing SnNb₂O₆ shell with high crystallinity was successfully fabricated on a NaNbO₃ nanowire through a molten salt treatment of the NaNbO₃ nanowire of the starting material with SnCl₂, whereas the fabrication was not successful on the TT phase of a niobia nanowire. The difference will come from the formation processes of SnNb₂O₆ crystals (ion-exchange reaction vs thermally induced crystallization reaction). The core/shell nanowire obtained from NaNbO₃ showed photocatalytic activity comparable to that of H₂ evolution in the presence of an electron donor under visible-light irradiation (λ > 420 nm), compared with the corresponding bulky counterpart

[Co(bpy)₃]^3+/2+ and [Co(phen)₃]^3+/2+ Electron Mediators for Overall Water Splitting under Sunlight Irradiation Using Z‑Scheme Photocatalyst System

[Co­(bpy)₃]^3+/2+ and [Co­(phen)₃]^3+/2+ redox couples were revealed to play as electron mediators for Z-scheme photocatalyst systems composed of Ru/SrTiO₃:Rh and BiVO₄ powders for overall water splitting under visible light irradiation. These electron mediators were effective for only the combination of SrTiO₃:Rh with BiVO₄. They did not work when nondoped SrTiO₃ and TiO₂ of H₂-evolving photocatalysts and WO₃ of O₂-evolving photocatalysts were employed. These results indicated that the affinity between photocatalysts and the Co-complex electron mediators was important. The photocatalytic activity depended on pH. Neutral pH conditions gave the highest activity for overall water splitting. Overall water splitting by the present system steadily proceeded for a long time. The Z-scheme photocatalyst system was also confirmed to split water under sunlight irradiation at the rates depending on weather. Moreover, overall water splitting by the Z-scheme photocatalyst system with the Co-complex electron mediator using a reaction cell in which the Ru/SrTiO₃:Rh suspension was divided from BiVO₄ suspension by a membrane filter resulted in H₂ evolution separated from that of O₂

Photocatalytic Properties of Layered Metal Oxides Substituted with Silver by a Molten AgNO₃ Treatment

K₄Nb₆O₁₇ (BG: 3.67 eV) and Na₂W₄O₁₃ (BG: 3.12 eV) layered oxide photocatalysts with wide band gaps were treated with a molten AgNO₃ to substitute K⁺ and Na⁺ with Ag⁺, resulting in red-shifts of absorption edges in diffuse reflectance spectra. A part of Na⁺ ions in the interlayer of Na₂W₄O₁₃ was substituted with Ag⁺ ions by the molten AgNO₃ treatment with keeping the layered structure. Both Ag­(I)-substituted K₄Nb₆O₁₇ and Na₂W₄O₁₃ showed photocatalytic activities for O₂ evolution from aqueous solutions containing a sacrificial reagent utilizing the absorption bands newly formed by the Ag­(I)-substitution. Notably, the Ag­(I)-substituted Na₂W₄O₁₃ produced O₂ under visible light irradiation. When ball-milled Na₂W₄O₁₃ was treated with a molten AgNO₃, the Ag­(I)-substitution rate increased. The Ag­(I)-substituted Na₂W₄O₁₃ with ball-milling showed higher photocatalytic activity for O₂ evolution than that without ball-milling. Z-schematic water splitting proceeded under visible light irradiation by combining the Ag­(I)-substituted Na₂W₄O₁₃ of an O₂-evolving photocatalyst with Ru-loaded SrTiO₃ doped with Rh of a H₂-evolving photocatalyst

Reducing Graphene Oxide on a Visible-Light BiVO₄ Photocatalyst for an Enhanced Photoelectrochemical Water Splitting

Bismuth vanadate (BiVO₄) is incorporated with reduced graphene oxide (RGO) using a facile single-step photocatalytic reaction to improve its photoresponse in visible light. Remarkable 10-fold enhancement in photoelectrochemical water splitting reaction is observed on BiVO₄−RGO composite compared with pure BiVO₄ under visible illumination. This improvement is attributed to the longer electron lifetime of excited BiVO₄ as the electrons are injected to RGO instantly at the site of generation, leading to a minimized charge recombination. Improved contact between BiVO₄ particles with transparent conducting electrode using RGO scaffold also contributes to this photoresponse enhancement

Epidermal Neuromedin U Attenuates IgE-Mediated Allergic Skin Inflammation

<div><p>Although keratinocyte-derived neuropeptide neuromedin U (NMU) mediates the proinflammatory effects of innate-type mast cell activation, no information is available on the physiological roles. Here, to investigate the effects of NMU on IgE-mediated allergic skin inflammation, we determined whether IgE-mediated inflammation associated with severe scratching was induced in <i>Nmu</i>^<i>-/-</i> mice administered repeated hapten applications to the ear or footpad. Dry skin was induced by targeted deletion of <i>Nmu</i>. Mice administered repeated hapten application developed IgE-mediated allergic inflammation characterized by severe scratching and increased serum IgE levels only when the ear, and not the footpad, was subjected to scratching, indicating that depletion of NMU from the epidermis alone does not drive such allergic inflammation. Thus, the susceptibility of <i>Nmu</i>^<i>-/-</i> mice to allergic inflammation depends primarily on scratching dry skin. Further, allergic skin inflammation mediated by FcεRI cross-linking in <i>Nmu</i>^<i>-/-</i>mice was inhibited by prior injection of NMU. These results indicate that NMU plays an important physiological role as a negative regulator during the late stage of IgE-mediated allergic skin inflammation.</p></div

Differences in the responses of mice after repeated hapten application to the ear or footpad.

<p>(A) A hapten-specific ITH reaction is indicated by rapid ear swelling 0.5 h after each elicitation (n = 10). (B) Ear thickness (n = 10). (C) Number of mast cells in the ear (n = 5). (D) Serum IgE levels of mice after repeated hapten application to the ear (n = 10). (E) Serum IgE levels of mice after repeated hapten application to the footpad (n = 10). (F) Total number of scratching episodes from 7:00 PM–7:00 AM (n = 10). (A–F) Data are expressed as the mean ± SEM. *<i>P</i> < 0.05, ** <i>P</i> < 0.01.</p

Histological analyses of the ears of B6 and <i>Nmu</i>^-/- mice after repeated hapten exposure.

<p>(A) Hematoxylin-eosin (HE) staining of B6 and (B) <i>Nmu</i>^-/- mice on day 28 (n = 5). Original magnification, ×100. (C), Numbers of histologically identifiable dermal mast cells (MC), eosinophils (Eo), and neutrophils (Ne) in the ears of B6 and <i>Nmu</i>^-/- mice (n = 5). *<i>P</i> < 0.05, **<i>P</i> < 0.01.</p

Effects of NMU on ITH mediated by two types of FcεRI cross-linking.

<p>(A) ITH responses were induced by TNCB application to the footpad of B6 or <i>Nmu</i>^-/- mice previously injected with TNP-specific IgE (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160122#pone.0160122.s001" target="_blank">S1A Fig</a>). Different concentrations of TNP-specific IgE (0.01–1.0 μg in 20 μl of PBS per footpad) were injected 3 days before applying TNCB as follows: 0.05 μg to 0.2 μg of IgE achieved concentrations equivalent to that achieved in the serum of these mice after repeated hapten exposure on days 7–21 (2.5–10 μg/ml). (B) ITH was induced by injecting 0.2 μg of TNP-specific IgE into the footpads of B6 or <i>Nmu</i>^-/- mice followed by the injection of 25 ng of anti-mouse IgE. NMU (50 pmol) or vehicle (PBS) was injected one day before injection of mice with an anti-mouse IgE (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160122#pone.0160122.s001" target="_blank">S1B Fig</a>). In B6 mice, ITH was decreased by NMU released from keratinocytes upon injection compared with that of similarly treated <i>Nmu</i>^-/- mice. (C) Numbers of histologically identifiable dermal mast cells (MC), eosinophils (Eo), and neutrophils (Ne) in the footpads of B6 and <i>Nmu</i>^-/- mice (n = 4). Data are expressed as the mean ± SEM (n = 10), *<i>P</i> < 0.05, **<i>P</i> < 0.01.</p

Photocatalytic Reduction of Carbon Dioxide over Ag Cocatalyst-Loaded ALa₄Ti₄O₁₅ (A = Ca, Sr, and Ba) Using Water as a Reducing Reagent

Ag cocatalyst-loaded ALa₄Ti₄O₁₅ (A = Ca, Sr, and Ba) photocatalysts with 3.79–3.85 eV of band gaps and layered perovskite structures showed activities for CO₂ reduction to form CO and HCOOH by bubbling CO₂ gas into the aqueous suspension of the photocatalyst powder without any sacrificial reagents. Ag cocatalyst-loaded BaLa₄Ti₄O₁₅ was the most active photocatalyst. A liquid-phase chemical reduction method was better than impregnation and in situ photodeposition methods for the loading of the Ag cocatalyst. The Ag cocatalyst prepared by the liquid-phase chemical reduction method was loaded as fine particles with the size smaller than 10 nm on the edge of the BaLa₄Ti₄O₁₅ photocatalyst powder with a plate shape during the CO₂ reduction. CO was the main reduction product rather than H₂ even in an aqueous medium on the optimized Ag/BaLa₄Ti₄O₁₅ photocatalyst. Evolution of O₂ in a stoichiometric ratio (H₂+CO:O₂ = 2:1 in a molar ratio) indicated that water was consumed as a reducing reagent (an electron donor) for the CO₂ reduction. Thus, an uphill reaction of CO₂ reduction accompanied with water oxidation was achieved using the Ag/BaLa₄Ti₄O₁₅ photocatalyst

Cytokine mRNA expression in the ears of B6 and <i>Nmu</i>^-/- mice after repeated hapten application.

<p>Results are expressed as fold-increase in expression in the ears of each mouse before hapten application, as assessed by the value of the mean ± SEM (n = 4–6). <i>P</i> < 0.05, * <i>P</i> < 0.01.</p