Protective effects of corni fructus extract in mice with potassium oxonate-induced hyperuricemia.

Corni fructus is consumed as food and herbal medicine in Chinese culture. Studies have revealed that corni fructus exhibits potent antioxidant activity; however, few studies have investigated the ability of corni fructus to lower uric acid concentrations. In this study, the xanthine oxidase (XO) inhibition and uric acid-lowering effect of corni fructus extract (CFE) were evaluated in mice with potassium oxonate-induced hyperuricemia. Hyperuricemia is a chronic disease prevalent worldwide and is associated with high recurrence rates. In addition, drugs used to treat hyperuricemia induce side effects that discourage patient compliance. Hyperuricemia induces metabolic imbalances resulting in accumulative uric acid deposition in the joints and soft tissues. Hyperuricemia not only induces gout but also interrupts hepatic and renal function, thereby trigging severe inflammation and various complications, including obesity, nonalcoholic fatty liver disease, diabetes, and metabolic diseases. In this study, the ethyl acetate fraction (EAF) of CFE resulted in yields of antioxidant photochemical components significantly higher than those of CFEs formed using other substances. The EAF of CFE exhibited high free radical scavenging activity and XO inhibition and effectively lowered uric acid concentrations in the animal model of chemically induced hyperuricemia. The results of this study can serve as a reference for the prevention of preclinical gout as well as for functional food research.

[Research on the Time-Histories of Exited Radicals during the Combustion of Methylcyclohexane by Emission Spectroscopy].

By using three monochromator! detecting systems, the light emissions of excited-state OH*, CH* and C* radicals during the transient combustion of methylcyclohexane at high temperatures behind the reflected shock wave have been measured. The dependence of the time-history and the relative intensity of excited radicals on the temperature have been obtained. The reflected shock temperatures are 1 200-1 700 K, the shock pressure is 1.5 atm, the mole fraction of methylcyclohexane is 0.1% and the equivalence ratio is 1.0. At the beginning of the combustion process, these three radicals were produced at the same time. The durations of these radicals became shorter when the temperature increases. At the same ignition temperature, the durations of CH* and OH* are longer than that of C2*. The C2* signal disappears below 1 400 K. The emission intensities of OH* and CH* are not sensitive to the temperature at T < 1 400 K. However, at high temperature (T > 1 400 K), the peak intensity of CH* increases rapidly as temperature increases, while C2* and OH* increase slowly. Current results were compared to the simulation results of corresponding chemical reaction mechanism. The obtained time-history of OH* radical matches well with the prediction of mechanism at low temperatures, but shows difference at high temperatures. The time-history of CH* radical matches well between experimental and simulated results at high temperatures, however, the simulated durations of CH* are longer than the experimental results at low temperatures. Current work provides experimental data to validate and optimize corresponding chemical reaction mechanism containing excited-state species.

[Measurement of Soot Yield from the Pyrolysis of Toluene at High Temperatures by Laser Extinction Method].

The measurement system for the detection of soot production as high-temperature pyrolysis of hydrocarbon fuels behind the reflected shock wave was established. By using the laser extinction method, the soot yields of toluene/argon mixtures were measured at high temperatures. The mole fractions of toluene were 0.25% and 0.5% while the pressures were approximate 2 and 4 atm. The temperatures ranged from 1 630 to 2 273 K. The dependence of soot yield on the temperature, pressure and fuel concentration was obtained. With the changes of temperature, the soot yield is a Gauss distribution. The soot yield increases as the pressure or fuel concentration increases. The maximum of soot yield was as high as 55%. The peak temperature of soot yield was not changed dramatically with the pressure. However, it changed from 1 852 to 1 921 K as the concentration of toluene increase from 0.25% to 0.5%. Moreover, we compared the soot yield between toluene and methylcyclohexane at pressure of 4 atm with fuel concertation of 0.5%. During the pyrolysis of methylcyclohexane, the peak temperature of soot yield was 2 045 K, which is about 135 K higher than that of toluene. However, the maximum soot yield of methylcyclohexane is only 1/8 of toluene. This work provides experimental reference for the research of soot particle emission in the engines and the mechanism of soot formation.

Modification of chitosan membrane with poly(vinyl alcohol) and biocompatibility evaluation.

This work aimed to overcome chitosan (CS) membrane' drawbacks: mainly stiffness and hydrophobic surface by adding poly(vinyl alcohol) (PVA) and evaluate their biocompatibility. The chemical structure, crystalline and thermal properties were studied by FT-IR, XRD and DSC. The mechanical properties and wettability of CS/PVA membranes were studied by tensile test and static contact angle measurement. In vitro biocompatibility was also evaluated by MTS cytotoxicity assay and SEM examination. The results suggest that adding PVA into CS membrane could greatly improve CS membrane's flexibility and wettability. All the membranes prepared were biocompatible and have potential applications in GTR technology.

[Experimental study on p53 gene mutation in keloid fibroblasts].

OBJECTIVE: To explore the significance and the role of the p53 gene mutation in the exon 4 to 8 in keloid fibroblasts. METHODS: Tissue samples from twelve patients with keloid and twelve hyperplastic scar respectively were harvested for in vitro culture of fibroblasts, and normal skin samples from the same patients were employed as the control. Polymerase chain reaction-based single-strained conformational polymorphism (PCR-SSCP) and DNA sequencing were employed to detect p53 gene mutations of the fibroblasts. RESULTS: The points and frameshift mutations in the exon 4, 5, 6, 7 of p53 gene were identified in 9 of the 12 keloid tissue samples. No p53 gene mutation was detected in all hyperplastic scar and normal skin samples. CONCLUSION: p53 gene mutation might play an important role in the formation and development of keloids.