Au Modified F-TiO2 for Efficient Photocatalytic Synthesis of Hydrogen Peroxide.

In this work, Au-modified F-TiO2 is developed as a simple and efficient photocatalyst for H2O2 production under ultraviolet light. The Au/F-TiO2 photocatalyst avoids the necessity of adding fluoride into the reaction medium for enhancing H2O2 synthesis, as in a pure TiO2 reaction system. The F- modification inhibits the H2O2 decomposition through the formation of the ≡Ti-F complex. Au is an active cocatalyst for photocatalytic H2O2 production. We compared the activity of TiO2 with F- modification and without F- modification in the presence of Au, and found that the H2O2 production rate over Au/F-TiO2 reaches four times that of Au/TiO2. In situ electron spin resonance studies have shown that H2O2 is produced by stepwise single-electron oxygen reduction on the Au/F-TiO2 photocatalyst.

A novel "turn-on" fluorescent sensor for hydrogen peroxide based on oxidized porous g-C3 N4 nanosheets.

An oxidized, porous graphitic carbon nitride nanosheets (CNNs) was successfully obtained via a bottom-up approach. The inner filter effect (IFE) of Fe (III) tetrakis (1-methyl-4-pyridyl) porphyrin pentachlorideporphyrin pentachloride (FeTMPyP) on the CNNs results in fluorescence quenching of the CNNs due to the overlap of FeTMPyP absorbance band and CNNs emission band. It is interesting that the quenched fluorescence could be "turned on" in response to the participation of H2 O2 , which caused by decomposition of FeMPyP. In this study, for the first time, a porous fluorescence probe based on CNNs and FeTMPyP was designed and an excellent H2 O2 detection performance with a large detection range of 0.1 ~ 100 µM and a detection limit of 0.07 µM was achieved. Furthermore, the proposed method was successfully used for H2 O2 detection in RAW 264.7 cells.

Inhibitory effect of Athelia rolfsii exopolysaccharides on organ damage in lead-exposed Kunming strain mice.

Herein, Athelia rolfsii exopolysaccharides (AEPS) were used to alleviate organ damage in lead-exposed mice. Analysis of the body weight growth rate and visceral index revealed that AEPS maintained the normal body weight growth rates in lead-exposed mice. Biochemical indicators (T-SOD, CAT, MDA) in serum revealed that AEPS increased the activity of T-SOD in the serum of lead-exposed mice. The lead concentrations in the brain, liver, kidneys, testis and faeces were measured by flame atomic absorption. The percent reductions in lead accumulation in these organs were 76.65% (brain), 60.42% (liver), 78.43% (kidneys) and 56.47% (testis). The data suggest that a significant portion of the lead was expelled in the faeces. The results proved that AEPS prevented lead accumulation in the organs of lead-exposed mice. A histological evaluation of the brain, liver, kidneys and testis also revealed that AEPS significantly alleviated liver and kidney damage caused by lead poisoning and protected neurons and sperm cells. We hypothesize that the ingested AEPS chelated the lead in the digestive system of the mice, leading to excretion through the faeces. Thus, AEPS represent a promising method of detoxification following lead poisoning.

Development and validation of a three-dimensional computational fluid dynamics model of root canal irrigation.

INTRODUCTION: Root canal irrigation plays an important role in the debridement and disinfection of the root canal system and is an integral part of root canal preparation procedures. The aim was to construct a three-dimensional computational fluid dynamics (CFD) model of root canal irrigation, with a suitable turbulence model, and validate it to provide a novel method for studying the root canal irrigation. METHODS: A camcorder was used to record the effect of irrigation in the in vitro model. An exact replica of the geometry and the physical parameters of the in vitro irrigation model were used in CFD analysis, considering four turbulent models. The in vitro irrigation model was used as the reference for the evaluation of the CFD models. RESULTS: The result showed that CFD analysis based on a shear stress transport (SST) k-omega turbulence model was in close agreement with the in vitro irrigation model. The in vitro and CFD analyses showed that the irrigant in the curved canal flushes only up to a limited distance beyond the tip of the needle. The results of the CFD analysis also showed that laminar flow exists in the needle lumen and transit the transitional and turbulent flow around the side-vent outlet of the needle and needle tip. CONCLUSIONS: The results suggested that CFD based on a SST k-omega turbulence model has the potential to serve as a platform for the study of root canal irrigation.