大气中氟污染对牡丹影响的调查分析

对大气氟污染与观赏植物牡丹叶片中的含氟量之间的关系进行了分析。结果表明：(1)一定时间内牡丹叶片的吸氟量和积累量成正相关。(2)牡丹叶片中的含氟量与测定点距污染源的距离呈负相关。(3)牡丹叶尖枯病是因大气氟污染所致，并非病理原因。     

Bubble-point measurements for the system CO2 + aqueous ethanol solutions of boldo leaf antioxidant components (boldine and catechin) at high pressures

The bubble-points pressures of solute(s) + ethanol + water + CO₂ mixtures were determined visually using a synthetic method in an experimental apparatus that included a variable-volume equilibrium cell. Tested solutes included boldo leaf tincture, a boldine + catechin mixture, pure boldine, and pure catechin. Uncertainties in bubble-point pressures were estimated to be <5%, based on comparisons with literature values and replicate measurements. The largest effect we observed was an average increase of 205% in the bubble-point pressure when decreasing the ethanol-to-water ratio from 63:37 to 37:63 (w/w). The bubble-point pressure increased 11% when increasing the temperature from 313 to 343 K, and decreased 8.2% when increasing the concentration of solids from 400 to 1500 ppm. The bubble-point pressure was higher for boldo leaf tincture than for a boldine + catechin mixture having the same boldine-to-catechin weight ratio, but this was partially due to a lower content of solids in the tincture. On the other hand, bubble-point pressures of the boldine + catechin mixture were marginally (0.33%) higher than the weighed average of the bubble-point pressures for pure boldine and pure catechin.     

Separation,quantification, spectral properties and stability of photosynthetic pigments on CN-coated HPTLC plates

Summary Chlorophylls, phaeophytins a and b, -carotene, lutein, violaxanthin and neoxanthin can be separated in 15 min on HPTLC, CN-coated sheets using chloroform-hexane-methanol (25-70-05 v/v). The algebraic characteristics of calibration curves and of the absorbance decay with time have been determined for each component. Solid phase spectra have been established from 370 to 700 nm and their variations have been examined with respect to the amounts of pigments spotted on the plates and to the storage time of chromatograms in the dark at 4°C.Pigments extracted with chloroform from barley leaves were analysed using the described method. A 5% accuracy is normally to be expected, and the sensitivity ranges from 0.5 pmol (-carotene) or 1 pmol (chlorophylls a and b) to 12 pmols (lutein) in quantitative determinations at 425 nm.     

Phytochemical profiles,antioxidant and anti-acetylcholinesterasic activities of the leaf extracts of Rhamnus lycioides subsp. oleoides (L.) Jahand. & Maire in different solvents

In this work, the extracts obtained with different solvents from the leaves of Rhamnus lycioides subsp. oleoides (L.) Jahand. & Maire were studied for their phytochemical profile and then for their antioxidant and acetylcholinesterase inhibitory activities. The phytochemical profiles of the extracts in n-hexane, dichloromethane, ethyl acetate, methanol, anthraquinone rich and water, showed the presence of different compounds belonging to several classes of natural products such as flavonoids, anthraquinones, saccharides and fatty acids. For what concerns the biological tests, the ethyl acetate, methanol and anthraquinone rich extracts showed the highest activities in both assays due to the high amount of compounds possessing those properties such as flavonoids and anthraquinones. By consequence, these specific extracts of the species may be considered to be potential sources of natural antioxidant and anti-acetylcholinesterasic compounds.     

The stability of foliations of orientable 3-manifolds covered by a product

We examine the relationship between codimension one foliations that are covered by a trivial product of hyperplanes and the branched surfaces that can be constructed from them. We present a sufficient condition on a branched surface constructed from a foliation to guarantee that all perturbations of the foliation are covered by a trivial product of hyperplanes. We also show that a branched surface admits a strictly positive weight system if and only if it can be constructed from a fibration over .

     

Transport behavior of ellagic acid of pomegranate leaf tannins and its correlation with total cholesterol alteration in HepG2 cells

The aim of this study was to investigate whether ellagic acid in pomegranate leaf tannins could be transported into HepG2 cells and its transport behavior. High‐performance liquid chromatography coupled with a 996 photodiode array detector at 254 nm was applied. The mobile phase was an acetonitrile–water solution (containing 0.1% triethylamine, pH 3.0; 16:64, v/v, for determining ellagic acid in cells). The flow rate was 0.8 mL/min. Cells were incubated with pomegranate leaf tannins with 100 and 50 µg/mL (containing 1.71 and 0.85 µg/mL of ellagic acid, respectively) for a specific time, then lysed and sonicated in methanol to extract intracellular ellagic acid. A 10 µL aliquot of sample was injected into the HPLC system to determine ellagic acid concentration. The results showed that ellagic acid in pomegranate leaf tannins could be transported into the cells, which was in correlation with total cholesterol alteration in the cells. This is the first time that the transport behavior of ellagic acid through HepG2 cells in vitro has been comprehensively demonstrated. Copyright © 2008 John Wiley & Sons, Ltd.     

An investigation of the structural aspects of the tomato fruit by means of quantitative nuclear magnetic resonance imaging

In this study, magnetic resonance imaging (MRI) was applied to study the structural aspects of the tomato fruit. The main study was performed on tomatoes (cv. Tradiro) using a 0.2-T electromagnet scanner. Spin-echo images were acquired to visualize the tomato macrostructure. The air bubble content in tissues was evaluated by exploiting susceptibility effects using multiple gradient echo images. The microstructure was further studied by measuring spin–spin (T₂) and spin–lattice (T₁) relaxation time distributions. Nuclear magnetic resonance relaxometry, macro vision imaging and chemical analysis were used as complementary and independent experimental methods in order to emphasize the MRI results. MRI images showed that the air bubble content varied between tissues. The presence of gas was attested by macro vision images. Quantitative imaging showed that T₂ and T₁ maps obtained by MRI reflected the structural differences between tomato tissues and made it possible to distinguish between them. The results indicated that cell size and chemical composition contribute to the relaxation mechanism.     

基于光谱技术的航天育种番茄品种鉴别方法的研究

为了实现航天育种番茄不同品种的快速光谱鉴别,采用主成分分析法对光谱数据进行聚类分析,并将小波变换用于对大量光谱数据的压缩,同时结合神经网络建立了番茄品种鉴别模型.该模型将压缩后的数据作为神经网络的输入,加速了神经网络的训练速度.通过对太空育种突变株M1和M2及其亲本番茄品种的共105个番茄叶片样本建立训练模型,并用每个品种15个样本,共45个番茄叶片的样本进行预测.结果表明,用该方法对航天育种番茄不同品种的鉴别正确率达到97.8%.说明文章提出的方法具有很好的分类和鉴别作用,为航天育种番茄不同品种的快速鉴别提供了一种新方法.     

基于烟叶近红外光谱主成分数据的投影方法研究及其在复烤配方中的应用

对近红外技术在烟草中的应用作了简要的概述,报道了两种基于近红外光谱主成分的投影矢量求解方法,分别简称为PPF_PCA和PPF_Eig,并对两种方法在复烤配方中的应用与评价做了比较研究.对9类烟叶工业分级样品光谱进行一维投影分析的结果表明:PPF_PCA方法得到的一维投影值的类间差异性和类内差异性均大于PPF_Eig方法,其中各类间投影均值的平均绝对偏差前者约为后者的1.26倍.同时应用第一维投影值所占贡献率的情况对此结果进行了解释,PPF_PCA方法一维投影值所占贡献率为93%,PPF_Eig方法一维投影值所占贡献率为77%,前者约为后者的1.21倍,因此,PPF_PCA方法得到的一维投影值中包含更多类间和类内的差异性信息.应用烟叶各类工业分级样品的一维投影图能客观的评价各类样品之间的相似性及各类内样品之间的差异性,可方便的作为烟叶复烤配方的参考依据,同时在其他农产品(如中药等)配方中也具有较好的应用前景.