Experimental autoimmune uveoretinitis (EAU) is an animal model of non-infectious uveitis and is developed by immunization with retinal antigen, interphotoreceptor retinoid-binding protein (IRBP). ...Nuclear factor erythroid 2- (NF-E2-) related factor 2 (Nrf2) is responsible for regulating antioxidant and inflammatory responses. In this study, we investigated the role of Nrf2 on the development of EAU. Clinical and pathological examination demonstrated that retinal inflammation was exacerbated in Nrf2 knockout (Nrf2 KO) mice compared to wild type (WT) mice, and the expression of inflammatory cytokines (IFN-γ, IL-6, and IL-17) in the retina was significantly elevated in Nrf2 KO mice. GFAP positive cells (astrocytes) and Iba-1 positive cells (microglia cells) in the retina were more numerous in Nrf2 KO mice compared to WT mice. Furthermore, we examined the suppressive effect of the Nrf2 activator CDDO-Im (2-cyano-3,12 dioxooleana-1,9 dien-28-oyl imidazoline) on the development of EAU. The treatment with CDDO-Im significantly reduced the clinical and pathological score of EAU compared to those of vehicle-treated mice. These findings suggest that Nrf2 plays a regulatory role in the pathogenesis of autoimmune uveoretinitis and the activation of the Nrf2 system may have therapeutic potential for protecting vision from autoimmune neuroinflammation.
This critical review shows the basis of photocatalytic water splitting and experimental points, and surveys heterogeneous photocatalyst materials for water splitting into H2 and O2, and H2 or O2 ...evolution from an aqueous solution containing a sacrificial reagent. Many oxides consisting of metal cations with d0 and d10 configurations, metal (oxy)sulfide and metal (oxy)nitride photocatalysts have been reported, especially during the latest decade. The fruitful photocatalyst library gives important information on factors affecting photocatalytic performances and design of new materials. Photocatalytic water splitting and H2 evolution using abundant compounds as electron donors are expected to contribute to construction of a clean and simple system for solar hydrogen production, and a solution of global energy and environmental issues in the future (361 references).
Bismuth vanadate (BiVO4) is an effective visible-light-driven photocatalyst for oxygen evolution from water. To understand the mechanism of photocatalytic oxidation of water, it is important to ...detect and characterize holes at the surfaces of powdered catalysts. Here, we report the transient absorption of BiVO4 in a wide time range from subpicosecond to 200 μs upon the excitation across the band gap with 400 nm femtosecond pulses. The effect of electron scavenger (Fe3+) on transient absorption decays indicates that the transitions at λ < 700 nm are mainly contributed by holes at the surfaces. While the transient absorption at λ > 700 nm rises almost instantaneously, the absorption λ < 700 nm has a slower rise component of τ ∼ 15 ps due to filling of surface traps with holes. Moreover, the rise component is modulated with strongly oscillating signals caused by coherent excitation of an external phonon mode between Bi3+ and VO4 3–. Thus, the transitions at λ < 700 nm associated with surface-trapped holes are strongly coupled to the external phonon mode. This study demonstrates that the time-domain spectroscopy is useful for characterizing the vibrational structure specific to the surface charge trap sites of powdered photocatalysts.
BiVO4 photocatalysts for O2 evolution, which work under visible light irradiation, were prepared by an aqueous process. The BiVO4 photocatalysts were obtained by the reaction of layered potassium ...vanadate powder (KV3O8 and K3V5O14) with Bi(NO3)3 for 3 days in aqueous media at room temperature. Highly crystalline monoclinic and tetragonal BiVO4 were selectively synthesized by changing the ratio of vanadium to bismuth in the starting materials. X-ray diffraction and scanning electron microscopy measurements showed that the monoclinic BiVO4 was formed via a tetragonal BiVO4 intermediate. Tetragonal BiVO4 with a 2.9 eV band gap mainly possessed an ultraviolet absorption band while monoclinic BiVO4 with a 2.4 eV band gap had a characteristic visible light absorption band in addition to the UV band. The UV bands observed in the tetragonal and monoclinic BiVO4 were assigned to the band transition from O2p to V3d whereas the visible light absorption was due to the transition from a valence band formed by Bi6s or a hybrid orbital of Bi6s and O2p to a conduction band of V3d. The photocatalytic activity for O2 evolution from an aqueous silver nitrate solution under UV irradiation (300 < λ < 380 nm) on the tetragonal BiVO4 was comparable to that on the monoclinic BiVO4. The monoclinic BiVO4 also showed the high photocatalytic activity for the O2 evolution under visible light irradiation (λ > 420 nm). When the monoclinic BiVO4 was calcined at 700−800 K the activity was increased. The activity of this monoclinic BiVO4 was much higher than that of BiVO4 prepared by a conventional solid-state reaction. The quantum yield at 450 nm for the O2 evolution on the monoclinic BiVO4 was 9%.
Abstract
IL-17A and IL-17F are both involved in the pathogenesis of neutrophilic inflammation observed in COPD and severe asthma. To explore this, mice deficient in both
Il17a
and
Il17f
and wild type ...(WT) mice were exposed to cigarette smoke or environmental air for 5 to 28 days and changes in inflammatory cells in bronchoalveolar lavage (BAL) fluid were determined. We also measured the mRNA expression of keratinocyte derived chemokine (
Kc
), macrophage inflammatory protein-2 (
Mip2)
, granulocyte–macrophage colony stimulating factor (
Gmcsf)
and matrix metalloproteinase-9 (
Mmp9
) in lung tissue after 8 days, and lung morphometric changes after 24 weeks of exposure to cigarette smoke compared to air-exposed control animals. Macrophage counts in BAL fluid initially peaked at day 8 and again on day 28, while neutrophil counts peaked between day 8 and 12 in WT mice. Mice dual deficient with
Il17a and 1l17f
showed similar kinetics with macrophages and neutrophils, but cell numbers at day 8 and mRNA expression of
Kc
,
Gmcsf
and
Mmp9
were significantly reduced. Furthermore, airspaces in WT mice became larger after cigarette smoke exposure for 24 weeks, whereas this was not seen dual
Il17a and 1l17f
deficient mice. Combined
Il17a
and
Il17f
deficiency resulted in significant attenuation of neutrophilic inflammatory response and protection against structural lung changes after long term cigarette smoke exposure compared with WT mice. Dual IL-17A/F signalling plays an important role in pro-inflammatory responses associated with histological changes induced by cigarette smoke exposure.
Molecule-based preparation of lithium niobate nanowires was achieved by proper combination of a niobium oxooxalate complex, a structure-directing reagent, and a lithium source. Structural and ...photophysical properties of the nanowires obtained were characterized by several microscopic and spectroscopic techniques. The nanowire was employed as a photocatalyst for overall water splitting, and H(2) or O(2) evolution reaction from an aqueous solution containing a sacrificial reagent under UV light irradiation to show enhanced photocatalytic properties as compared with a bulky counterpart prepared by a solid state reaction. The factors contributing to the enhancement of the photocatalytic performance were suggested to be an increase in active sites for the photocatalytic reaction in conjunction with a large surface area and a small particle size.
Photocatalyst sheets consisting of H2 evolution photocatalyst (HEP) and O2 evolution photocatalyst (OEP) particles applied to an underlying conductive layer show promise with regard to promoting ...efficient and scalable water splitting. One of the most important challenges in enhancing the performance of such systems is establishing efficient charge transfer between photocatalyst particles that are often thickly stacked on the conductive layer. In this study, reduced graphene oxide (RGO) is investigated as an additional solid mediator to the conductive layer to bridge particulate photocatalysts and thus ensure effective charge transfer. Photocatalyst sheets made of RhCrOx/LaMg1/3Ta2/3O2N as the HEP and BiVO4:Mo as the OEP are applied to an Au layer together with RGO. The activity of this system is 3.5 times greater following the incorporation of the RGO. Charaterization analyses reveal that RhCrOx/LaMg1/3Ta2/3O2N particles tens of nanometers in size are fixed on larger, micrometer‐sized, BiVO4:Mo particles by RGO photoreduced from GO in situ. The RGO facilitates charge transfer between particles that are distant from the underlying Au layer and thus involves more photocatalyst particles in the water splitting reaction. It is concluded that the incorporation of conductive materials into the photocatalyst particle layer can effectively enhance the water splitting activity of photocatalyst sheets.
Reduced graphene oxide incorporated into the photocatalyst sheet, composed of RhCrOx/LaMg1/3Ta2/3O2N as a hydrogen evolution photocatalyst and BiVO4:Mo as an oxygen evolution photocatalyst embeded in an Au layer, effectively facilitates charge transfer between particles that are distant from the underlying Au layer and enhances the activity for Z‐scheme water splitting by 3.5 times.
Cu(i)-substituted metal oxide photocatalysts were prepared using molten CuCl treatment of wide band gap photocatalysts. The Cu(i)-substituted metal oxide photocatalysts possessed a new absorption ...band in the visible light region and showed photocatalytic activity for hydrogen evolution from an aqueous solution containing sulfur sacrificial reagents under visible light irradiation. Notably, the Cu(i)-K
La
Ti
O
and Cu(i)-NaTaO
photocatalysts showed relatively high activities for hydrogen evolution and gave apparent quantum yields of 0.18% at 420 nm. These photocatalysts responded up to 620 nm. Thus, Cu(i)-substitution using a molten CuCl treatment was an effective strategy for sensitizing a metal oxide photocatalyst with a wide band gap to visible light.
Z-Scheme water splitting by photocatalyst sheets is a promising approach for efficient and scalable H2 production. One of the most important challenges in developing such photocatalyst sheets is the ...application of photocatalysts with long absorption edges. In this study, RhCrO x -loaded LaMg1/3Ta2/3O2N (RhCrO x /LaMg1/3Ta2/3O2N) and Mo-doped BiVO4 (BiVO4:Mo), with absorption edges at 600 and 540 nm, are investigated as the hydrogen evolution photocatalyst and oxygen evolution photocatalyst in photocatalyst sheets, respectively. The (RhCrO x /LaMg1/3Ta2/3O2N)/Au/BiVO4:Mo sheet exhibits water splitting activity that is ∼5 times higher than that of corresponding powder suspensions. Stable water splitting is achieved under visible light using the (RhCrO x /LaMg1/3Ta2/3O2N)/Au/BiVO4:Mo sheet coated with an amorphous TiO2 protective layer. However, the results show the low H2 evolution activity of the RhCrO x /LaMg1/3Ta2/3O2N imposes a ceiling on the activity of the photocatalyst sheet. The surface modification of LaMg1/3Ta2/3O2N with ZrO2 effectively enhances its H2 evolution activity by reducing the density of defects on the surface of LaMg1/3Ta2/3O2N. Accordingly, the activity of the photocatalyst sheet is almost doubled when ZrO2-modified LaMg1/3Ta2/3O2N is used. The solar-to-hydrogen energy conversion efficiency is still low (1 × 10–3%), although this work expands the possibility for the development of photocatalyst sheets capable of functioning under irradiation by long-wavelength photons.
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