基于带缺失PISA数据对中国学生科学素养的诊断分析

利用DINA模型(Deterministic inputs,noisy and gate model)对PISA2015中国学生科学素养数据进行建模,使用贝叶斯M CMC算法实现对缺失数据的自动填补和模型参数的估计.     

Changes in polyphenol fractions and bacterial composition after in vitrofermentation of apple peel polyphenol by gut microbiota

The changes in polyphenol fractions after in vitro fermentation of apple peel polyphenol (APP) by gut microbiota as well as the effects of APP on the growth, pH value, short-chain fatty acids (SCFAs) production and intestinal flora composition of gut microbiota fermentation were firstly explored in this study. The relative abundance of Lactobacillus in the APP group was 49.55% with an increment of 49.40% compared with the blank group, while that of Bifidobacterium was 13.32%. Moreover, the flora produced 37.093 ± 0.478 mM of SCFAs including acetic acid, propionic acid, butyric acid and valeric acid during the process of fermentation, thus reduced the environmental pH value. In addition, polyphenol fractions in APP were altered by gut microbiota fermentation to some extent, for example, glycosides were hydrolysed to aglycones. These findings suggested APP as a potential prebiotic agent to alleviate the disorder of intestinal flora.     

Investigation into adsorption equilibrium and thermodynamics for water vapor on montmorillonite clay

The isothermal adsorption curves for water vapor on montmorillonite were measured by a gravimetric adsorption system. Dent's model was employed to estimate the adsorption behaviors of water vapor on primary adsorption sites and secondary adsorption sites. The thermodynamics analysis of water vapor adsorption was performed. At low vapor pressure region, primary adsorption predominates, and with increasing vapor pressure, secondary adsorption becomes notable. Primary adsorption sites have an evidently stronger adsorption affinity than secondary adsorption sites. With increasing vapor pressure, Gibbs free energy variation rapidly increases and then reduces slowly. Although increasing vapor pressure raises adsorption spontaneity on primary adsorption sites, the enhancement in vapor pressure decreases the spontaneity of water vapor adsorption on secondary adsorption sites. As adsorbed loading increases, isosteric heat of adsorption and entropy loss decrease first and then increase quickly. The gradually growing water clusters are responsible for the increase of entropy loss at late stage.     

Changes in the content and antioxidative activity of β-carotene and its metabolite vitamin A during gastrointestinal digestion and absorption and optimisation of HPLC-based detection

The β-Carotene (BC), an important precursor of vitamin A (VA), possesses antioxidant activity but is fat-soluble and has low bioavailability. In previous in-vitro assays evaluating antioxidant and 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) free radical scavenging, both BC and VA showed a strong ability to scavenge radicals and protected cells from oxidative stress. Here, we used artificially simulated gastrointestinal digestion and Caco-2 cell absorption models to evaluate the bioavailability of the BC during gastrointestinal digestion and absorption using high-performance liquid chromatography (HPLC) analysis. We observed high absorptive and transfer rates of BC and detected retinol metabolites (Vitamin A). Therefore, BC can be detected in the acidic gastrointestinal environment using HPLC. Optimised method provided better separation of BC and VA in the column, improving the accuracy of the test results.     

Neoagarooligosaccharide Protects against Hepatic Fibrosis via Inhibition of TGF-β/Smad Signaling Pathway

Hepatic fibrosis occurs when liver tissue becomes scarred from repetitive liver injury and inflammatory responses; it can progress to cirrhosis and eventually to hepatocellular carcinoma. Previously, we reported that neoagarooligosaccharides (NAOs), produced by the hydrolysis of agar by β-agarases, have hepatoprotective effects against acetaminophen overdose-induced acute liver injury. However, the effect of NAOs on chronic liver injury, including hepatic fibrosis, has not yet been elucidated. Therefore, we examined whether NAOs protect against fibrogenesis in vitro and in vivo. NAOs ameliorated PAI-1, α-SMA, CTGF and fibronectin protein expression and decreased mRNA levels of fibrogenic genes in TGF-β-treated LX-2 cells. Furthermore, downstream of TGF-β, the Smad signaling pathway was inhibited by NAOs in LX-2 cells. Treatment with NAOs diminished the severity of hepatic injury, as evidenced by reduction in serum alanine aminotransferase and aspartate aminotransferase levels, in carbon tetrachloride (CCl₄)-induced liver fibrosis mouse models. Moreover, NAOs markedly blocked histopathological changes and collagen accumulation, as shown by H&E and Sirius red staining, respectively. Finally, NAOs antagonized the CCl₄-induced upregulation of the protein and mRNA levels of fibrogenic genes in the liver. In conclusion, our findings suggest that NAOs may be a promising candidate for the prevention and treatment of chronic liver injury via inhibition of the TGF-β/Smad signaling pathway.     

玻璃轻石吸附亚甲基蓝的研究

主要研究了玻璃轻石对水中亚甲基蓝的吸附性能,研究了吸附平衡时间、酸碱度(pH值)、玻璃轻石的用量、水相中亚甲基蓝的起始浓度等因素对吸附能力的影响.实验结果显示,吸附在60 min内可达到吸附平衡,吸附过程的动力学方程用准二级动力学模型能更好地进行线形拟合,当水体中pH>2时吸附效果最好.水样中亚甲基蓝的起始浓度减少,亚甲基蓝的吸附率略有上升,吸附过程能用弗罗因德利希(Freundlich)吸附等温方程描述.     

Molecular Characteristics of Amyloid Precursor Protein (APP) and Its Effects in Cancer

Amyloid precursor protein (APP) is a type 1 transmembrane glycoprotein, and its homologs amyloid precursor-like protein 1 (APLP1) and amyloid precursor-like protein 2 (APLP2) are highly conserved in mammals. APP and APLP are known to be intimately involved in the pathogenesis and progression of Alzheimer’s disease and to play important roles in neuronal homeostasis and development and neural transmission. APP and APLP are also expressed in non-neuronal tissues and are overexpressed in cancer cells. Furthermore, research indicates they are involved in several cancers. In this review, we examine the biological characteristics of APP-related family members and their roles in cancer.