对羟基苯乙酮萃取实验研究

部分高校开设的有机化学萃取实验,采用是乙酸乙酯萃取质量分数为5%的苯酚水溶液,鉴于苯酚具有中等毒性和腐蚀性,在实验操作过程中,如萃取、有机相干燥、蒸馏溶剂回收等实验环节都会挥发,为了绿色化实验,减少指导教师和学生在实验过程中吸入有毒化合物及苯酚对环境的危害,选择了化妆品中常用添加剂对羟基苯乙酮替代苯酚作为研究对象,配制饱和水溶液,分别以乙酸乙酯和二氯甲烷为有机溶剂萃取对羟基苯乙酮,并锻炼学生萃取过程中如何破乳以及对比两种不同溶剂的萃取效果。

Viral Infections During Pregnancy:The Big Challenge Threatening Maternal and Fetal Health

Viral infections during pregnancy are associated with adverse pregnancy outcomes,including maternal and fetal mortality,pregnancy loss,premature labor,and congenital anomalies.Mammalian gestation encounters an immunological paradox wherein the placenta balances the tolerance of an allogeneic fetus with protection against pathogens.Viruses cannot easily transmit from mother to fetus due to physical and immunological barriers at the maternal-fetal interface posing a restricted threat to the fetus and newborns.Despite this,the unknown strategies utilized by certain viruses could weaken the placental barrier to trigger severe maternal and fetal health issues especially through vertical transmission,which was not fully understood until now.In this review,we summarize diverse aspects of the major viral infections relevant to pregnancy,including the characteristics of pathogenesis,related maternal-fetal complications,and the underlying molecular and cellular mechanisms of vertical transmission.We highlight the fundamental signatures of complex placental defense mechanisms,which will prepare us to fight the next emerging and re-emerging infectious disease in the pregnancy population.

Carbon sequestration benefits of the grain for Green Program in the hilly red soil region of southern China

Soil erosion disturbs not only the global carbon cycle,but it is a complex environmental problem.Revegetation could reduce carbon emission by controlling soil erosion and increase carbon sequestration and accumulation by fixing carbon in vegetation and soil.The Grain for Green Program(GFGP)of China is the largest ecological restoration program in the world closely related to land-use/land-cover change(LUCC).Systematically assessing the carbon sequestration benefit of GFGP is crucial for a better understanding of the effects of implementing GFGP and providing reasonable vegetation management.Therefore,we selected the hilly red soil region(HRSR)of southern China as a study area,which is one of the main ecologically vulnerable areas in China.We assessed the carbon sequestration in the GFGP area of the HRSR using the InVEST(Integrated Valuation of Environmental Services and Tradeoffs)model based on land-use/land-cover datasets during 2000e2015.Our results show that implementing GFGP is conducive to the enhancement of carbon sequestration services.Total carbon sequestration showed an increasing trend at a rate of 15.43%from 2000 to 2015.The most significant change mainly happened in Hunan Province with the shortest implementation time.The carbon sequestration of each carbon pool(namely aboveground biomass,belowground biomass,soil,and dead organic matter)also increased slightly.Additionally,for carbon sequestration,unused land converted to forest land is the most effective LUCC.This study can provide scientific support for the management and implementation of GFGP in the HRSR of China.

Impact and inhibitory mechanism of phenolic compounds on the formation of toxic Maillard reaction products in food

As one of the dominant reactions occurring during thermal treatment of food, the Maillard reaction not only leads to the formation of aroma, browning color and taste compounds, but also contributes to the formation of some unpleasant toxic substances including acrylamide,heterocyclic amines and advanced glycation end products.Polyphenols, one of the most abundant antioxidants in the human diet, are contained in different kinds of foods. In this review, some recent studies on the impact of dietary polyphenols on the formation of acrylamide, heterocyclic amines and advanced glycation end products formed during the Maillard reaction are summarized, including the research work conducted with both chemical model systems and real food model systems; the possible inhibitory mechanisms of different polyphenols are also summarized and discussed in this review. Basically we found that some dietary polyphenols not only scavenge free radicals, but also react with reactive carbonyl species,thus lowering the formation of toxic Maillard reaction products. This review provides a useful theoretical foundation for the application of polyphenols in food safety, and suggests some directions for further study of natural products as inhibitors against the formation of toxic substances in thermally processed food.

Antiglycative and anti-inflammatory effects of lipophilized tyrosol derivatives

To expand the application of tyrosol,a series of lipophilized tyrosol derivatives were synthesized via esterification of tyrosol with fatty acids of different chain lengths.The antiglycative activity of tyrosol esters so prepared was subsequently examined in the bovine serumalbumin/glucose system.A quasi-parabolic shape was observed when the activity was plotted against alkyl chain length.Additionally,the anti-inflammatory effects of these derivatives were evaluated against methylglyoxalinduced inflammation in RAW264.7 cells.The same trend on anti-inflammatory activity was found as in the antiglycation study.The results showed that tyrosol esters with C12:0 and C14:0 were two most efficient ones among all the tested derivatives.Thus,some lipophilized tyrosol derivatives were stronger antiglycative and anti-inflammatory agents compared to the parent compound,tyrosol.