Antioxidative activities of bran extracts from twenty one pigmented rice cultivars

Ethanol–water (70:30, v/v) extracts from the bran of rice seeds from twenty one pigmented and one nonpigmented rice cultivars were evaluated for antioxidative activities using the following tests: inhibition of peroxidation of linoleic acid; inhibition of peroxidation of rabbit lipid erythrocyte membranes; reduction of potassium ferricyanide, and scavenging of superoxide anions and hydroxyl radicals. With some exceptions, extracts from the pigmented rice seeds had higher antioxidative activity than did the nonpigmented variety. The following pigmented cultivars had the highest antioxidative activities in all tests: Jumlalocal-1, Parnkhari 203, DZ78, LK1-3-6-12-1-1, and Elwee. A significant correlation was also noted between reducing power, inhibition of erythrocyte ghost membrane peroxidation, and superoxide anion and hydroxyl radical scavenging. The results suggest that: (a) ferricyanide reducing power might be a useful and simple index for large-scale evaluation of antioxidative potencies of natural products present in rice; (b) pigmented rice varieties with high antioxidative activities provide a source of antioxidants and a genetic resource to develop new health-promoting rice cultivars.     

Behaviour of Dietary Fibre Supplements During Bread Dough Development Evaluated Using Novel Farinograph Curve Analysis

A regression model composed of two sigmoid functions with variable asymptotes was developed and used to analyse the dietary fibre supplement behaviour during bread dough mixing. Using eight commercial dietary fibres of different botanical origin and model wheat starch-gluten flour, farinograph curves for fibre-flour blends and for the flour only were performed. After smoothing of the curves with the regression model, difference farinograms as the fibre supplementation effects were determined. The results showed that the difference farinograms had two peaks, whose shape was strongly differentiated by the studied supplements. The presence of both peaks allowed distinguishing two kinds of the rheological activity of each fibre supplement: weakening and strengthening of the consistency of bread dough during its development. The carrot, oat, cranberry, and cacao fibres exhibited dominance of strengthening over weakening action. While chokeberry, carob, apple, and flax fibres were characterised by dominance of weakening over strengthening action. The analysis of both position and height of the peaks in the difference farinogram can be also helpful for determination of hydration kinetics of the fibres used for bread supplementation.     

尿石素A对巨噬细胞极化及巨噬-泡沫细胞形成的作用

旨在探究尿石素A对巨噬细胞极化及对巨噬-泡沫细胞形成的影响及相关的分子机制。结果发现,尿石素A通过调控不同标志基因的表达,不仅能够抑制RAW264.7小鼠巨噬细胞向促炎的M1型巨噬细胞极化,还能促进自然状态巨噬细胞向M2型巨噬细胞极化;油红O染色发现尿石素A能够显著抑制巨噬-泡沫细胞形成,实时荧光定量聚合酶链式反应检测说明尿石素A能够抑制胆固醇合成基因羟甲基戊二酸单酰辅酶A还原酶和脂肪酸合成酶基因的转录;此外,尿石素A显著上调三磷酸腺苷结合盒转运蛋白A1和G1基因的表达,该两个基因表达与促进了胆固醇的排出相关。本研究证明了尿石素A对巨噬细胞极化具有调控作用,同时尿石素A能够抑制巨噬-泡沫细胞形成和胆固醇合成。这些结果揭示了尿石素A具有潜在的抗动脉粥样硬化的作用,为之后深入研究提供了理论参考。     

中国母乳中低聚糖组分及含量变化——以中国广东江门地区为例

密集收取22位中国母亲共163个母乳样品,采用高效阴离子色谱法监测在不同泌乳期中22种母乳低聚糖(human milk oligosaccharides,HMOs)的组成和含量变化。结果表明,15种中性低聚糖含量在泌乳初期(初乳)达到最高值后逐渐减少(成熟乳),但是3-岩藻糖乳糖的含量在整个取样阶段均在持续增加。6种酸性低聚糖在泌乳初期稳定但后期随时间延长逐渐减少,其中唾液酸化-乳糖-N-四糖a只在部分样本中检出。基于Lewis血型类型,可将母亲分为分泌型组和非分泌型组。分泌型母亲的母乳中富含α-1-2-L-岩藻糖基化低聚糖(如2’-岩藻糖乳糖、乳酰-N-岩藻五糖Ⅰ、二岩藻糖基乳糖、乳酰-N-二岩藻六糖Ⅰ)。在分泌型与非分泌型母乳中,α-1-2-L-岩藻糖基化低聚糖的质量浓度范围分别为1 211~7 272 mg/L和100~920 mg/L;然而α-1-3/4-L-岩藻糖基化低聚糖(如乳酰-N-二岩藻六糖Ⅱ、乳糖-N-二岩藻糖基-八糖、3-岩藻糖乳糖、乳酰-N-岩藻五糖Ⅱ)的质量浓度范围则分别为181~2 722 mg/L和476~4 931 mg/L。总体表明,分泌型和非分泌型母亲在泌乳期内的HMOs的组成和含量均在不断变化且差异明显。     

钙化—碳化法连续化处理一水硬铝石拜耳法赤泥

提出了"钙化—碳化法"低成本、大规模综合利用拜耳法赤泥新工艺。为简化工艺流程,将钙化与碳化两个过程做了连续化的尝试,即在钙化后不进行固液分离直接进行碳化,钙化碳化两个过程可在同一反应器进行,减少了设备需求和能源损耗。对比试验结果表明,传统处理法和连续处理法的溶铝渣中Na_2O含量分别为0.17%和0.23%,氧化铝提取率分别为35.6%和34.6%,初步证明了连续化的可行性。     

基于广义可扩展 RPCA 滤波的超快超声脑血流与功能成像方法研究

开发高分辨和高灵敏度的小血管可视化技术,对相关组织病变的早期诊断和治疗监测具有重要的临床意义。 不同于传统聚焦超声,超快超声多普勒(μDoppler)成像技术凭借数千帧的成像帧率,可检测到小血流的瞬时变化。 组织杂波滤除和噪声抑制对于 μDoppler 的成像质量至关重要。 常用的杂波滤除方法为奇异值分解(SVD)方法,该方法利用信号时空相干性差异可快速实现组织杂波和血流信号分离,然而无法有效抑制噪声。 本研究创新性提出了一种基于广义可扩展的鲁棒主成分分析(GSRPCA)的杂波滤除方法,使用 Schatten p 范数和 lq 范数来加强鲁棒主成分分析(RPCA)模型的低秩约束和稀疏约束,增强了小血流信号的提取能力。 大鼠脑血流成像结果表明,GSRPCA 能够提升功率多普勒成像中血管的成像质量,相较 SVD 提高信噪比约 20 dB,且提高对比噪声比约 10 dB。 大鼠超声脑功能成像结果表明,GSRPCA 能够提升小血管血容量动态检测的灵敏度。 相关方法对超快超声成像杂波滤除的研究具有一定借鉴意义。     

一种基于北斗的珍稀濒危植物保护技术框架

针对珍稀濒危植物迁地保护中存在的环境差异和植物适应性难题,本文提出一种利用北斗高精准时空技术构建的植物迁地保护框架。该框架以精准农业技术和平行系统理论为依据,以珍稀濒危植物生态环境及其自身状态变化等信息的动态监测与数据采集为基础,通过构建人工生态系统和平行种植,解决迁地保护与自然生态环境的差异性问题,以及植物自然回归的适应性问题。本文提出的框架有利于提高迁地保护成功率,从而提升珍稀濒危植物迁地保护的效益。     

聚苯乙烯微球固定化海洋脂肪酶YS2071及其性能研究

采用6种不同孔径和亲疏水性的聚苯乙烯微球,通过吸附法固定化脂肪酶YS2071,筛选得到最佳载体,对固定化条件进行了优化并对其性能进行了研究。结果表明:粒径范围0. 6～1μm的氨基聚苯乙烯微球B具有最佳的固定化效果,在酶质量浓度5 mg/m L、p H 10、固定化温度20℃、振荡转速250 r/min、吸附时间6 h条件下,酶活回收率达到42. 82%;与YS2071脂肪酶游离酶相比,经固定化后的载体脂肪酶的温度稳定性、金属离子稳定性、有机溶剂稳定性、pH稳定性均明显增强; 25℃存储30 d后,固定化酶酶活保留率比游离酶酶活保留率提高了15. 09个百分点;固定化酶重复使用5次后,酶活保留率为63. 77%。