AUC工艺特点及应用

综合论述了AUC工艺的特点;阐述了AUC工艺的净化机制,列出了部分杂质的净化效率计算的百分值;认证了AUC的化学组成为(NH4)4[UO2(CO3)3];介绍了AUC工艺在铀水冶、纯化和转化过程中的应用。     

Assessment of the antioxidant capacity of a fermented grain food product,Antioxidant Biofactor (AOB), by using pyranine and pyrogallol red as a combined probe

The role of antioxidants contained in foods, beverages, and supplements against oxidative stress has received much attention. The capacity of antioxidants has been assessed by various methods. In this study, the antioxidant capacity of a complex mixture of fermented grains has been assessed by using two probes, pyranine and pyrogallol red (PGR). A supplement commercialised as Antioxidant Biofactor, AOB, was used as a substrate. The extracts from AOB obtained with water and dimethylsulphoxide (DMSO) inhibited the free radical-induced consumption of pyranine and PGR in a concentration-dependent manner. They also suppressed the free radical-induced oxidation of human plasma. It was estimated that 1 g of AOB contained, as Trolox equivalent, roughly 0.13 and 0.24 mmol (2.5 and 4.7 wt%) antioxidants, which could be extracted by water and DMSO, respectively. This study shows that the combination of the above two probes is useful for assessing the total content and activity of antioxidants contained in complex mixtures.     

抗菌药物药效学研究的若干进展

应用药效学特点并根据抗生素的作用机制可以把抗菌药物分为浓度依赖性和非浓度依赖性两类, 不同类抗菌药物具有不同的抗生素后效应(PAE)。临床应根据各种抗菌药物的药效学特点, 制定给药间隔, 以取得理想的抗菌疗效并防止细菌产生耐药性。     

The antioxidant properties of the cherimoya (Annona cherimola) fruit

Annona cherimola is an exotic fruit from the genus Annona, native to the Andean highlands in western South America. The cherimoya skin, flesh and juice were isolated and analyzed for antioxidant content using the oxygen radical absorbance capacity (ORAC) assay. The juice showed the highest antioxidant activity, while the flesh exhibited the lowest. The cherimoya skin, flesh and juice extracts were also incubated with Raji (Burkitt's Lymphoma) and HT-29 (colon cancer) cell lines, and the antioxidant uptake of cells was measured. Both cell lines, when subjected to cherimoya juice, showed the highest antioxidant uptake. The cells were then exposed to AAPH, a radical initiator, to simulate the conditions of cells under oxidative stress, and then subjected to cherimoya skin, flesh and juice extracts. Both cell lines absorbed more antioxidants after being pre-exposed to AAPH, indicating that cells under stress have the ability to import antioxidants.     

Correlation between plasma antioxidant capacity and verbascoside levels in rats after oral administration of lemon verbena extract

Phenylpropanoids are the main class of compounds from lemon verbena which have shown a wide biological activity, verbascoside being the most abundant one. In this work, the composition of a lemon verbena extract was elucidated by HPLC-ESI-MS/MS and one flavone and one methoxylated phenylpropanoid were found in this source for the first time. The antioxidant activity of the lemon verbena extract was fully characterised by several methodologies. Unexpectedly, the extract was especially active in lipophilic environments and lipid peroxidation inhibition assay, as it was found for pure verbascoside. The lemon verbena extract, containing verbascoside as its major bioactive compound, was acutely administered to rats and verbascoside was the only metabolite detected in plasma samples as measured by HPLC mass spectrometry. The correlation between the highest verbascoside concentration in plasma and maximum plasma antioxidant capacity was observed at 20 min as measured by different techniques, i.e. minimum malondialdehyde (MDA) generation, highest ferric-reducing ability of plasma (FRAP value) and maximum superoxide dismutase activity (SOD). Therefore, the in vitro measurements of the antioxidant activity of lemon verbena extract may significantly support the antioxidant activity observed in vivo in this work. Moreover, neither evidence of acute oral toxicity nor adverse effects were observed in mice when the lemon verbena extract containing 25% verbascoside was used at a dosage of 2000 mg/kg.     

反加料方式制备AUC的工艺研究

介绍了用NH3和CO2气作为沉淀剂,以反加料方式制备(NH4)4[UO2(CO3)3](AUC)的工艺研究.具体研究了反应温度、料液铀浓度、UF6水解液的加入速度等参数对反加料工艺制备AUC晶体的影响.试验表明:控制反应温度在60～70℃、料液铀浓度在200g/L、UF6水解液流量在40 L/h的条件下制得的AUC晶体氟含量低于1000 μg/g,松装密度在0.8g/cm3～1.0g/cm3之间,具有很好的流动性.     

K-S检验与mRMR相结合的基因选择算法

为了解决基因数据集的基因选择难题,提出一种基于K-S检验与最小冗余最大相关（Minimum Redundancy-Maximum Relevance,mRMR）原则的基因选择算法。该算法先采用K-S检验选择出具有一定区分能力的基因,然后对选择到的基因进行mRMR判断,保留与类别高度相关而其间相关性较小的基因构成最终被选基因子集。以SVM为分类器,以F1_measure、分类准确率和AUC为评价指标对本文算法选择的基因子集进行评估,并将本文算法与K-S检验、mRMR,以及经典的RELIEF和FAST算法进行比较。5个经典基因数据集上的平均实验结果揭示：本文算法的运行时间远低于mRMR算法,且其各项评价指标值优于其他比较算法。因此,本文提出的K-S检验与mRMR结合的基因选择算法能选择到非常有效的基因子集。     

基于图像处理的铁谱覆盖面积回归分析

首先阐述了利用计算机图像处理计算铁谱覆盖面积，进而计算铁谱定量参数的方法，然后介绍了回归分析的基本原理及其在定量分析中的应用。通过计算东风公司柴油机1000h疲劳试验油样铁谱图像覆盖面积，得到了该批油样的定量参数，经过回归分析得到了定量参数之间的回归曲线。结合机械的实际磨损情况确定了利用回归曲线进行磨损状态判断的方法，最后结合磨粒分析和油样PQP分析数据对回归分析的结果进行验证。研究表明结合多个定量参数的回归分析能够对柴油机的磨损状态进行正确的判断。     

Metabolic profile and biological activities of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco: Studies on the essential oil and polar extracts

We investigated the metabolic profile and biological activities of the essential oil and polar extracts of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco collected in south Portugal. Gas chromatography–mass spectrometry (GC–MS) analysis revealed that oxygen-containing monoterpenes was the principal group of compounds identified in the essential oil. Camphor (40.6%) and fenchone (38.0%) were found as the major constituents. High-performance liquid chromatography with diode array detection (HPLC–DAD) analysis allowed the identification of hydroxycinnamic acids (3-O-caffeoylquinic, 4-O-caffeoylquinic, 5-O-caffeoylquinic and rosmarinic acids) and flavones (luteolin and apigenin) in the polar extracts, with rosmarinic acid being the main compound in most of them. The bioactive compounds from L. pedunculata polar extracts were the most efficient free-radical scavengers, Fe²⁺ chelators and inhibitors of malondialdehyde production, while the essential oil was the most active against acetylcholinesterase. Our results reveal that the subspecies of L. pedunculata studied is a potential source of active metabolites with a positive effect on human health.