Purification,structural data and biological properties of polysaccharide from Prunus amygdalus gum

This work demonstrates the efficiency of almond gum polysaccharides (AGPs) as bioactive compounds. AGPs were first extracted using H₂O₂, in the presence of NaOH, at different times and temperatures. The optimal extraction conditions were 4% H₂O₂ and 2 N NaOH, for 7 h at 50 °C, leading to an extraction yield of 58.2% (w/w). After a purification step, the retained AGPs were characterised using high‐performance liquid chromatography showing a molecular weight of 99.3 kDa. The monosaccharide composition of AGPs were assessed using gas chromatography–mass spectrometry. AGPs were found to be a complex heteropolysaccharide with a repeating unit mainly composed of galactose, arabinose, xylose, mannose, rhamnose, and glucuronic acid with the respective ratios: 45:26:7:10:1:11. The acidic nature of the polysaccharide is due to the presence of glucuronic acid. Total antioxidant activity, free radical‐scavenging activity and reducing power assay of AGPs were investigated. The obtained results showed high antioxidant activities of AGPs. Furthermore, beyond 60 mg mL^?1, AGPs exhibited bacterial growth inhibition for five pathogenic strains: Escherichia coli, Staphylococcus aureus, Enterococcus feacalis, Pseudomonas aeruginosa and Salmonella typhimurium.     

Alleviation Effect of Lanthanum on Cadmium Stress in Seedling Hydroponic Culture of Kidney Bean and Corn

Since1970s,rare earths(RE)have been exten-sively used as micro-fertilizers for crops in China.Ithas already been proved that REcani mprove the pro-duction and quality of crops.However,there havebeen a fewinvestigations about using RE as regulatorin pollution ecology.For example,An et al[1]studiedthe effects of O3on wheat growth and the protectiveeffect of RE.Yan and Zhou et al[2,3]discussed theprotective effect of RE on plants under acid rainstress.Jia et al[4]and Hu et al[5]reported th…     

离子束混合工艺对材料抗蚀性能的影响

本文介绍了离子束混合工艺方法。与直接注入相比较,离子束混合所使用的设备造价低1/4—1/2,而生产效率可提高1—2个数量级,因而使生产成本大幅度降低,这无疑对离子束工艺的实际应用将产生巨大的促进作用。 通过对轴承材料(GCr15和Cr4Mo4V)经Cr、N、Ta不同元素的混合处理后,在0.5M H_2SO_4和0.1M NaCl的缓冲溶液中的阳极极化曲线表明经混合处理后的两种材料试样,其抗蚀能力和抗点蚀能力均大大提高,这与直接注入的试样效果是一致的。 通过俄歇谱仪和透射电镜的分析结果表明混合是成功的,且在一定的条件下,形成非晶组织。 本文的结论是,无论是离子的直接注入还是离子束混合,对提高轴承材料的抗腐蚀性能都是有效的方法,特别是离子束混合技术具有更大的应用前景。     

Nutritional response of mature rats to kidney bean (Phaseolus vulgaris) lectins

In a series of 10-day pair feeding experiments it was found that the nutritional value of diets containing beans was essentially the same for rats aged between 30 and 123 days. Thus net protein utilisation (NPU) values of 25–39 on diets containing Processor bean (35 g protein kg^?1) + egg albumin (65g protein kg^?1) were obtained. As food intakes were considerably reduced when rats were fed diets containing more than 35g protein kg^?1 of Processor bean, the measurement of protein utilisation became increasingly more difficult. The severe disruption of the brush borders of duodenal and jejunal enterocytes, originally observed when bean-containing diets were fed to young (30-day-old) rats was also found with rats up to the age of 120 days on similar diets. Similarly, the development of circulating anti-lectin antibodies in the animals showed no age dependence within the age limits investigated. It was also shown that oral immunisation did not protect the rats from the effects of toxicity and that the immune response was a result of continuous absorption of lectin throughout the feeding period. Thus the extent and the mechanism of toxicity of Phaseolus vulgaris bean lectins were found not to be dependent on the age or maturity of the animal.     

Rapid determination of chlorophylls in vegetable oils by laser-based fluorometry

The presence of chlorophylls in vegetable oils is considered undesirable due to their adverse effects on oxidative deterioration, bleachability and hydrogenation. The usual methods for determination of chlorophylls in vegetable oils are absorption spectrophotometry, fluorometry and liquid chromatography using fluorescence detectors. This paper outlines a fluorometric method using a laser as the excitation source. The chlorophylls in crude palm oil, rapeseed oil, soya bean oil and olive oil were determined directly by laser-based fluorometry using (a) a helium-neon laser (632-8 nm, 5 mW) as the excitation source and an optical-multichannel analyser (OMA) with an intensified diode array as the detector, and (b) a helium-neon laser and a photomultiplier tube as the detector. The method is especially suitable for the detection of chlorophylls in crude palm oil since no pre-extraction step is required. The levels of chlorophylls measured in vegetable oils using the laser technique was also compared against values obtained by conventional spectrophotometric methods. The simplicity and rapid quantification of laser based fluorometry suggest that this technique can be readily applied to the detection or a wide variety of fluorescing species in vegetable oils.     

绿豆纤维功能饮料的工艺研究

探讨了新型保健绿豆纤维功能饮料的生产工艺,对影响产品品质的几个主要因素进行了较为深入的探讨,提出了生产绿豆纤维功能饮料的最佳工艺条件。     

The emulsifying properties of a polysaccharide isolated from the fruit of Cordia abyssinica

Polysaccharide was isolated from Cordia abyssinica and its effect, at differing concentrations, on its emulsifying ability was determined. Emulsions of vegetable oil containing up to 1% of the polysaccharide in phosphate pH 7.4 buffer, were prepared by using a hand piston homogenizer. Emulsification was assessed by diluting samples of the emulsions in sodium dodecyl sulphate and measuring absorbance at 500 nm. Addition of increasing concentrations of the polysaccharide up to 1% enhanced emulsification and emulsion stability. Above 1% concentration the polysaccharide solutions were too viscous for making emulsions conveniently. At a constant concentration of the polysaccharide, addition of up to a 1% concentration of salt enhanced emulsion formation. Further addition of salt above 1% resulted in no further changes in emulsifying ability, but the stability of the emulsions formed decreased on increasing the concentration of salt above 1%. The effect of pH on emulsifying ability was investigated by preparing emulsions using buffers of different pH, from pH 3 to pH 13. The polysaccharide had poor emulsifying ability below pH 7. Emulsifying ability increased with pH between pH 7 and 11. At pH above 11 there was a decrease in emulsifying ability.     

黄原胶接枝共聚物降滤失剂应用性能评价

黄原胶（XG）具有优良的耐盐性和增稠降滤失性能，但耐温性较差。对XG分子结构的分析认为，可利用XG链上的活泼基团接枝丙烯酰胺等乙烯基单体，增强其耐温性能，用作耐温抗盐钻井液处理剂。对比了合成的黄原胶丙烯酰胺等接枝共聚物（XGG）降滤失剂与XG在淡水、4％盐水和饱和盐水钻井液中的增粘降滤失性能和抗温性能，并通过岩心膨胀试验对比了XGG、XG和KCl对页岩的抑制性能。试验结果表明，在淡水钻井液中XGG具有极强的增粘效果和降滤失能力，远远超过XG1随着钻井液矿化度的提高，XGG的性能有一定下降，但XGG在各种钻井液中均具有比XG更好的高温增稠和控制失水的能力；XG已具有优良的抑制性，XGG的抑制性得到进一步提高。     

户外像素管软质灌注胶的研制与应用

采用脂环族环氧树脂、柔韧性环氧树脂、改性脂环胺类固化剂为主要原料，研制出户外像素管灌注软胶，产品具有耐紫外线辐照、耐冷热冲击、粘接性好等特点。介绍其制备方法、性能及用。     

酰胺类除草剂对红小豆的安全性

针对当前红小豆农业生产中大量应用的酰胺类除草剂并丙草胺、并丙甲草胺，研究其对红小豆苗期的安全性。研究表明，在低温、土壤墒情好的条件下两种药剂均对红小豆不安全，主要表现在影响出苗率、抑制生长、根体积明显减少、真叶叶片皱缩扭曲、严重的叶缘开始发黄、根瘤减少、逐渐枯死。两种药剂药害程度相近、随剂量增加症状明显加重，高用量时拱土期施药比播后立即施药的药害相对较轻，随有机质含量的降低而药害加重。