Determination of 16 Species of OCPs in Water by Liquid-liquid Extraction-GC

[Objective] The research aimed to study the determination of 16 kinds of OCPs in water by liquid-liquid extraction -GC. [Method] The new method for determining 16 kinds of OCPs in water by liquid-liquid extraction -GC was established, and the influencing factors such as nitrogen pressure and water bath temperature were discussed. [ Result] Detection limit of the method was from 3.2 to 14.1 ng/L, the relative standard deviation was between 4.0% and 9.6%, and the average recovery ranged from 80.8% to 106.0%. By optimizing nitrogen pressure and water bath temperature in the sample pretreatment process, when nitrogen pressure was ＋0.087 kPa, and water bath temperature was ±36 ℃, recovery effect of this method was better. [ Conclusion] The determination method had accurate qualitative and quantitative results, and met detection requirement of 16 kinds of OCPs in water.

Comparison of Two Methods for Measuring Flavonoid Content of Fagopyrum megaspartanium Leaves

[Objective] The aim was to study the flavonoid content of Fagopyrum megaspartanium leaves by water bath and ultrasonic extractions.[Method] By using water bath extraction and ultrasonic extraction,the total flavonoid content in buckwheat leaves was measured with UV spectrophotometer.[Result] The optimum wavelength for determination of the content of flavonoid extracted from buckwheat leaves was 420 nm;the content of total flavonoid extracted by ultrasonic extraction and water bath extraction from buckwheat were 5.26% and 5.40% respectively;and the average total flavonoid content by water bath extraction was significantly higher than that by ultrasonic extraction.[Conclusion] The result is significant for the improvement of flavonoid content measurement of buckwheat.

Optimization of Extraction Process of Yingshan Cloud Tea Polysaccharides by Response Surface Methodology

[Objectives] This study was conducted to explore the optimal process conditions for hot water extraction of polysaccharides from Yingshan cloud tea. [Methods] Based on single factor experiments, with the extraction rate of polysaccharides as the response value and liquid-to-solid ratio, extraction temperature and extraction time as investigation factors, the optimum extraction process for tea polysaccharides from Yingshan cloud tea was determined by Box-Behnken central componse design and response surface analysis method. [Results] Under the conditions of the liquid-to-solid ratio of 50∶1(ml/g), the extraction temperature at 94 ℃ and the extraction time of 210 min, the extraction rate of polysaccharides from Yingshan cloud tea reached 2.16%. [Conclusions] This study will provide theoretical basis and reference for subsequent related research.

Habitat use and space preferences of Eurasian Bullfinches(Pyrrhula pyrrhula)in northwestern Iberia throughout the year

Background:For all vertebrates in general,a concerted effort to move beyond single season research is vital to improve our understanding of species ecology.Knowledge of habitat use and selection by Eurasian Bullfinches(Pyrrhula pyrrhula)is limited with regard to the non-breeding season.To date,research on the habitat of the Iberian subspecies iberiae consists of very general descriptions.In relation to space use,only broad features are available for the entire distribution range of Eurasian Bullfinches,including Iberia.Methods:In this study,seasonal preferences regarding habitat and space in a population of Eurasian Bullfinches are examined for the first time in the Iberian Peninsula,through direct observation during a six-year period.The essential habitat components,substrate selection and perch height were assessed.Results:Hedgerows were the key essential habitat component for bullfinches during all seasons.Nevertheless,small poplar plantations became increasingly important from winter to summer-autumn.Bullfinches perched mostly in shrubs/trees throughout the year,but there were significant seasonal changes in substrate use,ground and herbs being of considerable importance during spring-summer.Throughout the year,over half of the records corresponded to feeding,reaching almost 90%in winter.Generally,bullfinches perched noticeably lower while feeding.Male bullfinches perched markedly higher than females,notably singing males in spring-summer.Juveniles perched at a height not much lower than that of males.In all seasons,males tended to feed at greater heights than females.Bullfinches of different ages and sexes were seen bathing in all seasons except winter.Conclusions:Hedgerow habitat in general appeared to be valuable for bullfinches throughout the year.In summer and autumn,they selected sites with an abundance of food and shade,as well as shelter,a much-needed requirement for fledglings and moulting individuals.There was usually a close link between the most used and most consumed plant species in each season.Males appeared to assume a more important role in vigilance,and often they accompanied dependent young in June and July.Bullfinch conservation strategies should consider seasonal demand for habitat and space.

The Influence of Drying Temperature and Extraction Methods on a-Mangostin in Mangosteen Pericarp

The effects of drying temperature and extraction methods on α-mangostin content in mangosteen pericarp （Garcinia mangostana L.） powder were investigated. In the first part of experiment suitable drying temperature for retention α-mangostin content was determined. Three levels of drying temperatures （55, 65 and 75 ℃） were used in this study. The drying rates were increased with drying temperature. Room temperature extraction method was performed to investigate the effect of drying temperature on retention α-mangostin content in mangosteen pericarp. The α-mangostin content extracted at three different drying temperatures （55, 65 and 75 ℃） was 35.98 ± 0.49%, 40.32 ± 0.24%, and 37.79±0.34% w/w, respectively. The results showed that the suitable temperature for drying mangosteen pericarp was 65 ℃ that gave the highest of α-mangostin content. The second part of experiment was the comparison between extraction methods, such as shaking water bath extraction （SWE）, soxhlet extraction （SE） and microwave-assisted extraction （MAE）. The results show that MAE gave the highest extraction rate and α-mangostin content as compare to SWE and SE. The α-mangostin content extraction from SWE, SE and MAE are 45.83 ± 0.02, 34.82± 0.17 and 49.79 ± 0.15% w/w of crude extract, respectively.

Sliding wear behaviors of Nomex fabric/phenolic composite under dry and water-bathed sliding conditions

A Nomex fabric/phenolic composite was prepared,and its tribological properties were evaluated under dry and water‐bathed sliding conditions by a pin‐on‐disk tribometer.The resulting size of the friction coefficient for the Nomex fabric/phenolic composite in the study occurred in the following order:dry sliding condition>distilled water‐bathed sliding condition>sea water‐bathed sliding condition.The fabric composite’s wear rate from high to low was as follows:distilled water‐bathed sliding condition>sea water‐bathed sliding condition>dry sliding condition.Under water‐bathed sliding conditions,penetration of water into the cracks accelerated the composite’s invalidation process,resulting in a higher wear rate.We also found that the extent of corrosion and transfer film formed on the counterpart pin significantly influenced the wear rate of the Nomex fabric composite.Discussion of the Nomex fabric composite’s wear mechanisms under the sliding conditions investigated is provided on the basis of the characterization results.

Showering in Flint, MI: Is there a DBP problem?

Lead contamination in the City of Flint, MI has been well documented over the past two years, with lead levels above the EPA Action Level until summer 2016. This resulted from an ill-fated decision to switch from Detroit water（Lake Huron） with corrosion control, to Flint River water without corrosion control. Although lead levels are now closer to normal,reports of skin rashes have sparked questions surrounding tap water in some Flint homes.This study investigated the presence of contaminants, including disinfection by-products（DBPs）, in the hot tap water used for showering in the homes of residents in Flint. Extensive quantitative analysis of 61 regulated and priority unregulated DBPs was conducted in Flint hot and cold tap water, along with the analysis of 50 volatile organic compounds and a nontarget comprehensive, broadscreen analysis, to identify a possible source for the reported skin rashes. For comparison, chlorinated hot and cold waters from three other cities were also sampled, including Detroit, which also uses Lake Huron as its source water.Results showed that hot water samples generally contained elevated levels of regulated and priority unregulated DBPs compared to cold water samples, but trihalomethanes were still within regulatory limits. Overall, hot shower water from Flint was similar to waters sampled from the three other cities and did not have unusually high levels of DBPs or other organic chemicals that could be responsible for the skin rashes observed by residents. It is possible that an inorganic chemical or microbial contaminant may be responsible.