薄荷型卷烟和主流烟气中薄荷醇分析及其转移的研究

为了考察薄荷醇在主流烟气中的转移率,对薄荷型卷烟烟丝和主流烟气中薄荷醇含量进行了分析。烟丝和主流烟气粒相物中薄荷醇的萃取用无水乙醇为溶剂,萃取液用气相色谱-质谱联用法(GC-MS)分析,并用选择离子监测(SIM)、内标(正十七烷)标准曲线法测定薄荷醇的含量及其在主流烟气中的转移率。结果表明:所建立的方法准确、可靠,所测定组分在不同样品中的回收率在99.34%~100.04%之间,相对标准偏差小于2.6%,线性相关系数大于0.999,方法检出限为0.12μg/mL。不同焦油量的卷烟其薄荷醇在主流烟气中的转移率随卷烟焦油量升高而增高,最高达47.79%左右。     

水分子配位对叶绿素a氧化还原势与红外光谱的影响

以光系统I反应中心电子传递链上的辅助叶绿素a为目标,采用密度泛函理论中的B3LYP方法,结合三种基组,系统计算了该叶绿素及其两种配位分子模型在气相、模拟蛋白质环境和水中的氧化还原势和离解能;同时计算了这三种模型在气相中的几何结构、红外光谱及其13C、15N和2H的同位素标记谱.计算及分析结果表明:水分子配位引起镁离子偏离叶绿素a的卟啉环平面中央,导致以镁原子为中心的键角减小,Mg—N键长增长;而天冬酰胺对配位的水分子施加氢键影响后,使得Mg—N键进一步增长,镁离子与水分子中氧原子的配位键Mg—O键长减小,离解能增加,合成分子的氧化还原势减少;另外,分子的氧化还原势和配位键离解能随着相对介电常数的增加以及计算基组的增大而减小;三种分子模型的羰基(C襒O)和卟啉环上C襒C键的特征振动频率差值小于7cm-1,而同位素标记引起其峰位变化量的差值小于3cm-1.该计算为研究光合反应中心电子传递链上叶绿素a的作用与功能提供理论参考依据.     

Permanganate oxidation of alkenes. Substituent and solvent effects. Difficulties with MP2 calculations

The permanganate oxidation of alkenes has been studied both experimentally and computationally. Transition state structures were located for the reaction of permanganate ion with a variety of monosubstituted alkenes at the B3LYP/6-311++G** level. Although the calculated activation energy for the reaction with ethene was reasonable, the calculated effect of substituents, based on the energies of the reactants, was much larger than that experimentally found. This was shown to be due to the formation of an intermediate charge-dipole complex which led to the transition state. Reaction field calculations found the complex to disappear in a high dielectric constant medium, and the range of activation energies for the reaction in solution became quite small. MP2 calculations were carried out in order to have a comparison with the DFT results. MP2-MP4 gave unusual results for calculations on permanganate ion as well as chromate ion and iron tetraoxide. They also gave markedly unreasonable results for the activation energy of the reaction of permanganate with ethane. CCSD/6-311++G** calculations gave satisfactory results for permanganate ion and chromate ion. At this level of theory, the reaction of permanganate with ethene was found to have a very early transition state, when the bond lengths of the reactants just began to change. The reaction was calculated to be very exothermic (-69 kcal/mol), and this was confirmed via calorimetry. The rates of permanganate oxidation of allyl alcohol and acrylonitrile were determined, and they had similar reactivities. The kinetics and the products of the reaction of permanganate with crotonate ion were examined in some detail.     

基于单克隆抗体G250修饰的肿瘤细胞靶向基因载体研究

用宫颈癌细胞Hela表面高表达G250抗原的单克隆抗体G250修饰非病毒基因载体, 获得肿瘤靶向基因载体. 通过注射G250杂交瘤细胞于小鼠腹腔, 制备富含G250mAb的腹水, 用正辛酸-硫酸铵沉淀法和Protein A Agarose分离纯化, 获得高纯度的G250mAb. 通过二硫键将PEI与G250mAb偶联, 得到修饰的基因载体G250mAb-PEI, 研究其转基因靶向性. 结果表明, G250mAb-PEI对Hela细胞的基因转染具有显著的靶向性, 对Hela细胞的转基因效率是肝癌细胞HepG2(G250阴性)的2倍; 而对正常血管平滑肌细胞(SMC)的基因转染效率比Hela低近20倍, G250mAb修饰与否对SMC没有靶向性; 对3T3细胞的毒性显著低于未修饰的PEI, 表明G250mAb-PEI是一种高效、低毒和具有靶向性的基因载体.     

氢化物发生原子荧光法测定水处理剂聚合氯化铝中砷的含量

探讨了以硫酸预处理样品,硫脲-抗坏血酸混合液将As(Ⅴ)预先还原至As(Ⅲ),氢化物发生原子荧光法测定聚合氯化铝中砷含量的方法。结果表明,回收率为92.31%~105.10%,相对标准偏差为2.37%~5.55%。     

人参皂苷Rb1在大鼠体内的药物代谢研究

人参皂苷Rb1是人参中的达玛烷型三萜皂苷类化合物, 具有多种生物活性. 对人参皂苷Rb1代谢产物的分析已有报道, 在大鼠尿液、粪便、胃和大肠中共检出了5种代谢产物. 本文采用高效液相色谱-飞行时间串联质谱进行人参皂苷Rb1的体内代谢研究, 通过口服和静脉给予药物, 在大鼠尿液中共检出了人参皂苷Rb1的14种代谢产物, 并系统分析和推断了这些代谢物的转化规律和可能结构.     

4-(7-甲氧基-2,2-二甲基-2,3-二氢苯并呋喃-5-基)-2-芳氨基噻唑的合成、晶体结构与杀虫活性

以2-(2-甲基烯丙氧基)苯酚为原料, 经Claisen重排、呋喃环化、醚化、Friedel-Crafts乙酰化、α-溴代和噻唑环化等反应合成了22种4-(7-甲氧基-2,2-二甲基-2,3-二氢苯并呋喃-5-基)-2-芳氨基噻唑化合物. 化合物的结构经质谱、1H NMR和元素分析等确证. 采用单晶X射线衍射仪测定了化合物7j的晶体结构, 该晶体属于单斜晶系, 空间群为C2/c, 晶胞参数a=2.21140(12) nm, b=0.87602(5) nm, c=2.13911(12) nm, β=115.5380(10)°; V=3.7391(4) nm3, Z=8, Dc=1.375 g/cm3, F(000)=1616, S=1.046, μ=0.333 mm-1, 最终偏差因子R1=0.0390, wR2=0.1079. 杀虫活性实验结果表明, 化合物7a, 7b, 7h和7t在浓度为500 mg/L时对蚕豆蚜死亡率分别为95.12%, 62.60%, 57.53%和59.06%.     

阳离子交换树脂脱除罗非鱼酶解液腥味的研究

通过静态吸附实验研究了5种阳离子交换树脂对罗非鱼肉酶解液腥味的脱除效果,发现阳离子树脂均有适当的脱腥作用,其中D113型树脂效果最好。在单因素实验的基础上进行正交实验设计,优化D113型树脂脱腥工艺,结果表明,在25℃下脱腥的最佳工艺参数为酶解液pH值5.0、树脂用量5.0%(m/v)、接触时间1.0h。在此工艺条件下,酶解液的腥味最低,蛋白质回收率为80.61%。本工艺可用于鱼蛋白酶解液的脱腥。     

INTERFACIAL MOLECULAR DESIGN OF A RIGID- PARTICLE TOUGHENED POLYAMIDE 6 COMPOSITE

The effects of interfacial modifier on the mechanical properties of kaolin-filled polyamide 6 (PA6) have been studied. The interracial interaction between polyamide 6 and kaolin has been character ized by means of infrared spectroscopy (IR) and scanning electron microscopy (SEM). The results show that the role of the interracial modifier lies in forming an elastic interlayer with good adhesion between kaolin and PA 6. A composite with high impact strength, high tensile strength and high elastic modulus can be obtained by inserting the elastic interfacial modifier into the rigid-particle-filled polymer system.     

EFFECTS OF COUPLING AGENTS ON THE RHEOLOGICAL BEHAVIOR OF KAOLIN FILLED POLYAMIDE 6

An experimental study was carried out to investigate the effects of coupling agents on the rheological properties of kaolin filled polyamide 6(PA6). We have investigated the state of dispersion and interfacial interaction of the filled systems, using 'h:anning electron microscopy (SEM) and Molau test, respectively. It is found that the addition of the coupling agents to the PA6/ kaolin (20 wt percent) significantly decreases the melt viscosity and the melt elasticity (first normal stress difference). Moreover, the states of dispersion and the polymer/filler interactions have significant influences on the rheological properties of kaolin/PA6 systems. The rheological behavior of KH550 kaolin /PA6 system is different from that of KH560 kaolin/PA6 system, although chemical reactions have taken place between the surface of KH550 kaolin (or KH560 kaolin) and PA6 matrix during melt processing. This is attributable, in part, to the differences in the state of dispersion of kaolins in PA6 matrix and, to a great extent, to the differences in the extent of chemical reactions that have taken place between the filler and polymer matrix.