二甲基二烯丙基氯化铵/丙烯酸共聚凝胶的辐射合成与性质研究

采用γ辐射溶液聚合法合成了几种二甲基二烯丙基氯化铵 丙烯酸 (DADMAC AA)共聚凝胶 .实验结果表明单位体积溶液中二组分单体总摩尔数和丙烯酸 (AA)相对含量的增加使共聚凝胶力学强度明显增高 .在两种单体等摩尔比的情况下共聚体的凝胶含量随剂量增加而增加 ,且明显高于聚N ,N′ 二甲基二烯丙基氯化铵 (PolyDADMAC)凝胶 .体系中少量κ 卡拉胶 (KC)的加入可增强共聚凝胶韧性但对凝胶含量和强度影响甚微 .共聚凝胶溶胀性能测定结果表明DADMAC与AA摩尔比为 1∶2时凝胶溶胀比与体系pH值的关系呈现聚两性电解质性质 ,等电点pH值接近 4 5 .这种聚两性电解质性质在对铼Re(Ⅶ )离子浓集中也有所表现     

“两面神”型金纳米粒子比色检测铁离子的新方法

制备了一种聚乙二醇(PEG)和柠檬酸根不对称修饰的"两面神"型金纳米粒子(Janus AuNPs)比色传感器,并基于此建立了铁离子(Fe~(3+))比色检测的新方法。首先,利用柠檬酸钠还原法制备了粒径相对较大的金纳米粒子,随后,以玻片为基底,将大粒径金纳米粒子修饰在玻片上,利用玻片掩蔽部分柠檬酸根位点,并进一步在金纳米粒子非接触区域上修饰大量PEG链,得到柠檬酸根和PEG不对称修饰的Janus AuNPs。引入Fe~(3+)后,有限区域内的柠檬酸根诱导Janus AuNPs发生定向聚集,形成金纳米粒子寡聚体并在水溶液中保持稳定。Janus AuNPs溶液吸光度比值与Fe~(3+)浓度在1μmol/L～10 mmol/L范围内呈线性变化(y=0.129x+0.317),检出限为715 nmol/L。与同类方法相比,该方法操作简便、灵敏度高,且可极大拓宽检测的线性范围。     

光引发N-乙烯基吡咯烷酮在嵌段聚醚聚氨酯膜上接枝聚合的研究

本文研究了在碱性介质中,氮气氛下 N-乙烯基吡咯烷酮(N-VP)在嵌段聚醚聚氨酯(SPEU)膜上的接枝聚合。测定了接枝率与接枝液中 N-VP单体浓度、光照时间、催化剂浓度等条件的关系。测定了接枝后 SPEU 膜的吸水性,并用扫描电镜对膜表面进行了观察。对碱性介质中的接枝机理进行了初步探讨。     

Wound Healing Assay Using Microfluidic Channels

An approach was described to produce a wound area in vitro using laminar flow technique to selectively remove cells in microfluidic channels. Cell migration which plays an important role in the process of wound healing can be observed dynamically by this method. In order to prove our system, we have studied its properties by injecting NIH-3T3 cells into main channel and added several reagents to observe the mediatory influence. The results reveal that fibroblast growth factor-2(FGF-2), insulin-like growth factor 1(IGF-I), platelet-derived growth factor BB(PDGF-BB) and ascorbic acid(Vc) groups can promote cell migration compared with the control group. But the average migration distance was diminished in dexamethasone group. It can be concluded that this system can be used to analyze the process of wound healing.     

比色法测定蒙药铜灰体系中产生的*OH自由基

根据细胞色素C的氧化特性,采用比色法测定蒙药铜灰体系中产生的·OH自由基。实验证明,以盐酸羟胺为还原剂,在磷酸二氢钾缓冲溶液中测定,效果较好。该体系不受β-胡萝卜素的抑制,仅受硫脲的抑制,说明蒙药铜灰可作为筛选抗·OH自由基的消除剂,并具有“燥脓、清肺、肝之热”等功能。     

二元单体在棉纤维上的γ辐射接枝

在氮气气氛下用γ射线辐照的方法在棉纤维上接枝苯乙烯/马来酸酐、苯乙烯/甲基丙烯酸二甲胺乙酯、苯乙烯/醋酸乙烯酯二元单体. 研究了溶液中单体的浓度和二元单体的摩尔比等条件对接枝率的影响, 并探讨了两种单体的竞聚率对接枝率、接枝膜的组成及性能的影响. 结果表明决定二元接枝生成物结构比例的是二元单体的比例及其竞聚率. 接枝产物的红外、热重分析进一步佐证了竞聚率对不同二元单体体系接枝生成物结构的影响. X射线衍射结果表明棉纤维素上接枝不同的二元单体后均引起结晶度的下降, 而且结晶度随接枝率的增加而降低, 证明二元接枝反应是从纤维素无定型区通过第三相向结晶区逐步扩展的.     

松香产品中重质松节油成分的气相色谱/质谱法分析

利用水汽蒸馏提取法富集了松香产品中残留的重质松节油,经气相色谱／质谱联机分析,发现其主要由１９种单萜和倍半萜化合物组成,全部为香味物质（未知物除外）。为提高松香产品的品质和开发利用松香重质松节油提供了依据。     

布里渊放大器中Stokes光的高增益放大

微小Stokes信号光在布里渊放大器中得到放大,当Stokes信号光强度为015mj时,增益系数达到67。Stokes光增益决定于Stokes信号光强度及放大池中泵光与Stokes光的耦合程度,小信号Stokes光将得到较大的增益,并能得到较好的相位共轭效果     

Identification of wheat varieties using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry and an artificial neural network

A novel tool for variety identification of wheat (Triticum aestivum L.) has been developed: an artificial neural network (ANN) is used to classify the gliadin fraction analysed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS). The robustness of this novel method with respect to various experimental parameters has been tested. The results can be summarised: (i) With this approach 97% of the wheat varieties can be classified correctly with a corresponding correlation coefficient of 1.0, (ii) The method is fast since the time of extracting gliadins from flour can be reduced to 20 min without significant decrease in overall performance, (iii) The storage of flour or extracts under standard conditions does not influence the classification ability (i. e. the generalisation ability) of the method, and (iv) The classification obtained is not influenced by the identity of the operator making the analysis. This study demonstrates that a combination of an ANN and MALDI-TOFMS analysis of the gliadin fraction provides a fast and reliable tool for the variety identification of wheat. Copyright 1999 John Wiley & Sons, Ltd.     

Motion of Solitons in Deoxyribonucleic Acid (DNA) Double Helices with Dissipation

Under the first-order approximation, the general soliton solution of the plane base rotator model is obtained using the direct perturbation method, when taking the dissipation interaction in the DNA double helices dynamics into consideration. The stability condition of system leads to a relation among the soliton velocity, the coupling constants and the damping factor. It imposes limits to the maximum value of the soliton velocity and energy. An estimation of the value of the dissipation factor is given using recently published experimental data. Some practical problems such as the energy transmission and the semiconservative replication of B-DNA are discussed in detail.