Purification and structural characterisation of lipid transfer protein from red wine and grapes

Lipid transfer proteins (LTP) play a major role in plant defence and are of particular interest due to their known ability to cause allergic reactions. These proteins are expressed in grapes and also remain detectable after vinification, especially in red wine. However, it remains unknown whether the protein undergoes any changes during the vinification process. Here, we present a purification method for LTPs from Dornfelder grapes and wine. By liquid-chromatography–mass spectroscopy (LC–MS/MS) we identified LTPs from two different species (Vitis vinifera and Vitis aestivalis). Additionally, the purified LTPs were characterised using spectrometric methods, confirming their high purity and structural stability during vinification. We conclude that LTPs are resistant to the alcohol content (13.5 vol%), acidic milieu of wine and other ingredients present during the vinification process, indicating that the allergenic potential of grape LTP is not diminished by the vinification process.     

无甲醛水性内墙涂料的研制

目的　以 PAM代替水性内墙涂料中的 PVF,消除 PVF中游离甲醛对环境所造成的污染 .方法以丙烯酰胺为单体 ,在无引发剂条件下进行水溶液聚合 ,合成 PAM;以 PAM为胶粘剂 ,以淀粉胶和羧甲基纤维素为增稠剂 ,添加助剂制备成内墙涂料 .结果　制备出无甲醛水性内墙涂料 .结论　性能测试证明 :PAM完全能代替现行的以 PVF为胶粘剂的水性内墙涂料     

Selective flocculation of iron oxide-kaolin mixtures using a modified polyacrylamide flocculant

High molecular weight polyacrylamides were synthesized and successfully modified to contain up to 8·3% hydroxamate functional groups. The selective flocculation tests carried out on 1:1 iron oxide/kaolin mixtures using parent polyacrylamide, polyacrylic acid and the modified polyacrylamide, confirm the possibility of enhancing selectivity through introduction of iron chelating functional groups in commercially available polymers. Starting with a feed grade of 35% iron, 92% recovery with acceptable grade of 60% iron has been achieved using the modified polyacrylamide. NCL communication No. 4415     

13C and 23Na n.m.r. studies of the interactions between cations and kryptofix (2,2) bound to soluble or gel polyacrylamide

Interactions between univalent cations (Li⁺, Na⁺, K⁺, Ag⁺) and bivalent cations (Ba²⁺, Ca²⁺) with kryptofix (2,2) substituted polyacrylamide have been investigated using ¹³C n.m.r. The tendency to form complexes involves the dimensions of both the hydrated ion and the cavity size macrocycle and for Ag⁺ the nature of the interaction site. The sensitivity of the ²³Na n.m.r. method for detecting complex formation in solution from macromolecular species has been applied to the determination of the conditional formation constants of Na⁺ and Ba²⁺ complexes.     

HPAM/AlCit胶态分散体系成胶性能评价及其对岩石润湿性的影响

以部分水解聚丙烯酰胺、柠檬酸铝为主要材料合成了可用于油藏深部调驱的新型胶态分散体系(HACDS),评价了HPAM浓度、放置时间、HPAM/AlCit质量比对HACDS成胶性能的影响,并利用自吸吸入法研究了HACDS对岩石润湿性的影响.研究表明:随HPAM浓度的增加,HACDS的成胶时间缩短;随放置时间的增加,HACDS的粘度增大;HPAM/AlCit质量比对HACDS成胶时间有一定的影响;HACDS的注入可使岩石的润湿性向亲水方向转化;HACDS的注入量对相对润湿指数有一定的影响.分析认为HACDS在岩心中形成吸附膜是导致岩心润湿性改变的主要原因.     

均匀设计和神经网络优化高固量聚丙烯酰胺的合成工艺

通过均匀设计的方法探索合成高固含量低相对分子质量的聚丙烯酰胺的合成工艺,并利用人工神经网络对实验结果进行非线性拟合,通过筛选优化得到高浓度低相对分子质量聚丙烯酰胺的合成工艺条件.结果表明:通过均匀设计与人工神经网络结合,是一种很好地实验设计和优化实验条件的方法.     

交联聚合物溶液的剪切稳定性

采用核孔膜过滤和动态光散射法,研究了高相对分子质量低浓度的部分水解聚丙烯酰胺与柠檬酸铝反应所形成的交联聚合物溶液的剪切稳定性及降解机理.结果表明,随着剪切速率的增加,交联聚合物溶液对孔径为1.2μm的核孔膜的封堵能力降低,但仍能对孔径为0.4μm的核孔膜形成有效封堵.交联聚合物溶液受剪切作用后封堵性能下降的原因是体系中的交联聚合物线团粒径和部分水解聚丙烯酰胺分子线团粒径受剪切作用后变小,不能对核孔膜形成有效封堵.     

Preparation and characterization of polyacrylamide cryogels produced from a high‐molecular‐weight precursor. I. Influence of the reaction temperature and concentration of the crosslinking agent

A new type of cryogel was prepared through a reaction of high‐molecular‐weight polyacrylamide (viscosity‐average molecular weight ≈ 3 × 10⁶ Da) with glutaraldehyde in a moderately frozen aqueous medium. The influence of the crosslinking agent concentration and temperature of the reaction on the gel fraction yield, swelling characteristics, and morphology of the cryogels was investigated. The dependence of the gel fraction yield on the reaction temperature was bell‐shaped. The recognized regularities of the formation of this new type of polyacrylamide cryogel based on a high‐molecular‐weight precursor were very similar to those observed earlier for polyacrylamide cryogels synthesized through the cryopolymerization of monomeric precursors. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Investigation of thixotropy behavior of crude oil—Polyacrylamide emulsions

This investigation focuses on the study of the thixotropy behavior of crude oil–polyacrylamide emulsions. A wide range of crude oil and polymer concentrations were covered. Crude oil concentrations of 0–75% by volume and polymer concentrations of 0–10⁴ ppm were used. Two polyacrylamides of Alcoflood polymers, AF1235 and AF1285, were examined. RheoStress RS100 rheometer from Haake was employed to study the thixotropy behavior of crude oil–polymer emulsions. Measurements of thixotropy were conducted under the controlled rate mode. The aqueous solutions of Alcoflood polymers show thixotropy behavior. AF1235 aqueous solutions show lower hysteresis rheograms and thixotropy area than the aqueous solutions of AF1285. Polymer concentration shows strong influence on the ramp‐up and ramp‐down curves. The crude oil–polymer emulsions behave in an antithixotropy response instead of thixotropy behavior experience for the polymer aqueous solutions. The yield stress values of the crude oil–polymer emulsions increase strongly with polymer concentration for ascending and descending cycles. However, for polymer concentration of less than 1000 ppm, crude oil shows strong effects on the emulsion yield stress values for the ramp‐down cycles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

聚丙烯酰胺增强砂土保水性的试验研究

该研究使用的土样是彰武县章古台的风砂土，试验设 4个处理， 3次重复。试验表明，各试筒土样含水量随时间而递减，但应用聚丙烯酰胺处理的土样含水量始终高于对照的，聚丙烯酰胺具有保水和缓释的作用。