Steered polymorphic nanodomains in TiO2 to boost visible-light photocatalytic oxidation.

A breakthrough in enhancing visible-light photocatalysis of wide-bandgap semiconductors such as prototypical titania (TiO2) via cocatalyst decoration is still challenged by insufficient heterojunctions and inevitable interfacial transport issues. Herein, we report a novel TiO2-based composite material composed of in situ generated polymorphic nanodomains including carbon nitride (C3N4) and (001)/(101)-faceted anatase nanocrystals. The introduction of ultrafine C3N4 results in the generation of many oxygen vacancies in the TiO2 lattice, and simultaneously induces the exposure and growth of anatase TiO2(001) facets with high surface energy. The photocatalytic performance of C3N4-induced TiO2 for degradation of 2,4-dichlorophenol under visible-light irradiation was tested, its apparent rate being up to 1.49 × 10-2 min-1, almost 3.8 times as high as that for the pure TiO2 nanofibers. More significantly, even under low operation temperature and after a long-term photocatalytic process, the composite still exhibits exceptional degradation efficiency and stability. The normalized degradation efficiency and effective lifespan of the composite photocatalyst are far superior to other reported modified photocatalysts.

Coenzyme Q10 Sunscreen Prevents Progression of Ultraviolet-Induced Skin Damage in Mice.

The level of sun ultraviolet ray reaching the surface of the earth is increasing severely due to the rapid development of the society and environmental destruction. Excessive exposure to ultraviolet radiation causes skin damage and photoaging. Therefore, it is emerged to develop effective sunscreen to prevent ultraviolet-induced skin damage. This study was aimed at investigating the effects of Coenzyme Q10 (CoQ10) sunscreen on the prevention of ultraviolet B radiation- (UVB-) induced mouse skin damage. Three-month-old female mice were used, and they were randomly divided into four groups: control, model, CoQ10, and titanium dioxide (TiO2; positive control) groups. Our results showed that body weight, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, and DNA (cytosine-5)-methyltransferase 1 (DNMT1) protein expression were significantly decreased, while malondialdehyde (MDA) activity and metalloproteinase-1 (MMP-1) level were increased in UVB-treated mice. Besides, the stratum corneum was shed from the skin surface in the model group compared with the control group. In contrast, CoQ10 sunscreen prevented from UVB-induced skin damage, as well as reversing SOD, GSH-Px, and MDA activities, and MMP-1 and DNMT1 levels. Taken together, the current study provided further evidence on the prevention of UVB-induced skin damage by CoQ10 and its underlying mechanisms.

Insights into Ion Occupancy Manipulation of Fe-Co Oxide Free-Standing Cathodes for Li-O2 Batteries with Enhanced Deep Charge Capability and Long-Term Capability.

The merits of Li-O2 batteries due to the huge energy density are shadowed by the sluggish kinetics of oxygen redox and massive side reactions caused by conductive carbon and a binder. Herein, Fe-Co inverse spinel oxide nanowires grown on Ni foam are fabricated as carbon-free and binder-free cathodes for Li-O2 batteries. Superior high rate cycle durability and deep charge capability are obtained. For example, 300 cycles with a low overpotential under a fixed capacity of 500 mAh g-1 are achieved at a high current density of 500 mA g-1. In the deep discharge/charge mode at 500 mA g-1, the optimized Fe-Co oxide cathode can stably work for more than 30 cycles with the capacity maintained at about 2100 mAh g-1. Owing to the appreciable incorporation of Fe3+ into the surface of stable inverse spinel oxides, the regulated Fe-Co oxide cathodes possess a more stable and higher ratio of Co3+/Co2+, which offers improved adsorption ability of reactive oxygen intermediates and thus achieves the enhanced electrocatalytic performance in the higher current density. In addition, the morphology evolution from array to pyramid-like structure of nanowires further provides assurance in the superior cycle capability. By coupling pyramid-shaped nanowires with binary inverse spinel, the obtained Fe-Co oxide becomes a promising material for practical applications in Li-O2 batteries. This work offers a general strategy to design efficient mixed metal oxide-based electrodes for the critical energy storage fields.

Targeted Double Negative Properties in Silver/Silica Random Metamaterials by Precise Control of Microstructures.

The mechanism of negative permittivity/permeability is still unclear in the random metamaterials, where the precise control of microstructure and electromagnetic properties is also a challenge due to its random characteristic. Here silver was introduced into porous SiO2 microsphere matrix by a self-assemble and template method to construct the random metamaterials. The distribution of silver was restricted among the interstices of SiO2 microspheres, which lead to the precise regulation of electrical percolation (from hoping to Drude-type conductivity) with increasing silver content. Negative permittivity came from the plasma-like behavior of silver network, and its value and frequency dispersion were further adjusted by Lorentz-type dielectric response. During this process, the frequency of epsilon-near-zero (ENZ) could be adjusted accordingly. Negative permeability was well explained by the magnetic response of eddy current in silver micronetwork. The calculation results indicated that negative permeability has a linear relation with ω 0.5, showing a relaxation-type spectrum, different from the "magnetic plasma" of periodic metamaterials. Electromagnetic simulations demonstrated that negative permittivity materials and ENZ materials, with the advantage of enhanced absorption (40dB) and intelligent frequency selection even in a thin thickness (0.1 mm), could have potentials for electromagnetic attenuation and shielding. This work provides a clear physical image for the theoretical explanation of negative permittivity and negative permeability in random metamaterials, as well as a novel strategy to precisely control the microstructure of random metamaterials.

A Chinese herbal medicine (Modified Guomin Decoction) Influences the differentiation of CD4+ T-cell subsets in OVA-induced asthmatic mice.

OBJECTIVE: Modified Guomin Decoction (MGD) is an effective Chinese herbal medicine for treatment of various allergic diseases, especially allergic asthma. Its water decoction is conventionally used for treatment of allergic bronchitis in China. Up to date, the underlying mechanisms of this herbal combination have not been fully investigated yet. METHODS: In the in vivo study, the mice were treated with Chicken egg ovalbumin (OVA) and aluminum hydroxide gel as the classic allergic asthma animal model. After treatment with MGD, the lung tissues were examined by Histological assessment. The flow cytometric analysis was used to classify the CD4+ T-cell subsets. RT-PCR, Real time fluorescence quota PCR and Western blotting were used to analyze the gene expression of IL-4, IL-5, IFN-γ T-bet/GAIA-3 and Foxp3 in lung tissues. RESULTS: MGD significantly reduced ovalbumin-specific IgE production in mouse serum and suppressed inflammatory cell infiltration, thus, improved the asthma symptoms. The mechanistic studies indicated that MGD treatment mainly modified the differentiation of CD4+ T-cell subsets and improved their functions. These included that MGD enhanced the proportion of Th1-cell, reduced Th2-cell subsets to CD4+ cell and balanced Treg/Th17 cell populations in the asthmatic mice spleen tissues. For Th1-cells, MGD upregulated the gene expression of their cytokine IFN-γ and its transcription factor T-bet while it downregulated the gene expression of their cytokines of IL-4 and IL-5. For Th2-cells, MGD mainly downregulated its transcription factor GATA-3 in lung tissues of asthmatic mice. MGD suppressed the Th17-cell subsets in CD4+ cells and upregulated the expression of Foxp3, a specific transcription factor of Treg-cell.

Generation mechanism of negative permittivity and Kramers-Kronig relations in BaTiO3/Y3Fe5O12 multiferroic composites.

Recently, negative parameters such as negative permittivity and negative permeability have been attracting extensive attention for their unique electromagnetic properties. Usually, negative permittivity is well achieved by plasma oscillation of free electrons in conductor-insulator composites or metamaterials, while some attention has been paid to attaining negative permittivity in ceramics to reduce dielectric loss. In this paper, negative permittivity in barium titanate and yttrium iron garnet composites are reported which was well fitted by the Lorentz model. Further, negative permittivity behavior was verified via Kramers-Kronig relations, and it revealed that the causal principle still valid for negative permittivity resulted from dielectric resonance. The interrelationships among negative permittivity, capacitive-inductive transition and ac conductivity are discussed.