Megastigmane sesquiterpenoids from the pericarps of Trichosanthes kirilowii and their anti-complementary and anti-inflammatory activities.

The pericarps of Trichosanthes kirilowii Maxim. (T. kirilowi) have been traditionally used in Chinese medicine for their heat-clearing properties.

Trichosanates A-G and cucurbitacins W-Y, anticomplement monoterpenoids and cucurbitane-type triterpenoids from the pericarps of Trichosanthes kirilowii.

The pericarps of Trichosanthes kirilowii are often used to treat cough in traditional Chinese medicine, and its ethanol extract exhibited effective therapeutic effects on acute lung injury (ALI) in vivo caused by H1N1. An anticomplement activity-guided fractionation on the extract resulted in the isolation of ten new terpenoids, including seven monoterpenoids, trichosanates A-G (1-7), and three cucurbitane-type triterpenoids, cucurbitacins W-Y (8-10), as well as eleven known terpenoids (11-21). The new terpenoids' structures were determined by spectroscopic analysis, X-ray crystallographic analysis (1), electronic circular dichroism (ECD) analysis and calculations (2-10).

Improved Accuracy for Trace Element Analysis of Al and Ti in Quartz by Electron Probe Microanalysis.

The trace elements in quartz, Al and Ti, contain considerable information about mineral genesis, and determining their concentrations is of great importance in geology. Electron probe microanalysis has the advantages of non-destructive testing and high spatial resolution; however, it is a challenge to improve the accuracy and precision of trace element detection using this method. The important factors affecting accuracy include the fragility of quartz lattices at high beam currents and the methods used to determine the background.

A Mathematical Model for Determining Carbon Coating Thickness and Its Application in Electron Probe Microanalysis.

In electron probe microanalysis where materials are coated with a thin conductive carbon coat before analysis, the X-ray intensity detected from a specimen may be affected to various degrees by the thickness of the carbon coating. Differences in the carbon film thickness between specimens and standards may lead to errors in analytical results, particular for lower energy X-rays. In this study, we demonstrate that the location and the distance of the specimen relative to the carbon tip in the coating chamber can affect the thickness of the carbon film produced on the specimen surface during carbon coating.

Influence of microstructural features on thermal expansion coefficient in graphene/epoxy composites.

In this paper, theoretical calculations were conducted to determine the coefficient of thermal expansion (CTE) based on the effective medium approach using Green's function method. The influences of microstructural features were investigated, including volume fraction, aspect ratio, and the orientation of graphene fillers. Calculated results demonstrated strong anisotropy of CTE when all graphene sheets in the composite were aligned in the in-plane direction due to the large difference between the elastic moduli of the graphene and epoxy.