Study of normal and modified nucleosides in serum by RP-HPLC

Modified nucleosides derived predominantly from transfer ribonucleic acid (tRNA) have been studied as possible tumor markers. In this paper a reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been applied to study 15 normal and modified nucleosides in serum. The nucleoside levels in normal human serum were established, and the concentrations of 15 nucleosides in serum from 19 cancer patients were determined, it was found that the concentrations of modified nucleosides were significantly higher in patient sera. Based on 15 nucleoside concentrations in serum, factor analysis could classify correctly 90% of cancer patients from the normal humans Further work showed that urine was slightly better than serum when determining nucleosides as biological marker candidates. More work is ongoing to determine the clinical usefulness of modified nucleosides as tumor markers.

Excretion pattern investigation of urinary normal and modified nucleosides of breast cancer patients by RP-HPLC and factor analysis method

Modified nucleosides, formed post-transcriptionally in RNA by a number of modification enzymes, are excreted in abnormal levels in the urine of patients with malignant tumors. To test their usefulness as tumor markers, and to compare them with the conventional tumor markers, a reversed-phase high-performance liquid chromatographic (RP-HPLC) method and a factor analysis method have been used to study the excretion pattern of nucleosides of breast cancer patients. A clear cut differentiation of the breast cancer group and the healthy individuals in two clusters without overlapping was obtained. Copyright (C) 2000 John Wiley & Sons, Ltd.

Degradation products formed during UV-irradiation of humic waters

Natural humic lake water and aqueous solutions of humic substances were treated with ultraviolet (UV) radiation (λ = 254 nm). The effects on the dissolved organic carbon content (DOC) and the absorbance at 254 nm (Abs254) and 460 nm (Abs460) were monitored and the identity and concentrations of gas chromatographable organic degradation products were determined. The DOC content and the (Abs254) of the humic solutions decreased continuously with increasing UV-dose. Several aromatic and aliphatic degradation products were identified and roughly quantified The concentrations of aromatic hydroxy carboxylic acids and hydroxy aldehydes increased when relatively low UV-doses were used, but declined following further irradiation. The concentrations of aliphatic dibasic acids increased over the full range of UV-doses

UV-photooxidation as pretreatment step in inorganic analysis of environmental samples

Many laboratories deal with the determination of heavy metals, carbon, nitrogen and phosphorus. The first step in chemical analysis is a proper preparation of the investigated samples. The presence of organic substances can cause problems in many analytical methods. This paper describes the application of UV irradiation as a method of destruction of organic matter in the investigated samples.

水和土壤中LAS的提取及HPLC测定

<正> 1 引言合成洗涤剂中直链烷基苯磺酸盐(LAS)是目前生产和使用量最大的表面活性剂[1],同时也是环境中最常见、分布最广的有机污染物[2,3]。它可通过生活污水、垃圾及工业废水废渣等多种途径进入水体和土壤,造成了不同程度的环境污染[4,5]。准确、快速、经济地提取和测定环境样品中的LAS含量,是防治其污染的必要手段。目前水样中LAS的提取方法多为液-液提取法,土壤样品中LAS的提取多用索氏提取法。但这些方法步骤繁琐、费时,试剂消耗量大,且重现性不好[1]。本研究旨在建立一个快捷、准确、经济的水和土壤中LAS的提取和测定方法。 2 材料与方法

水质对UV/H_2O_2降解邻苯二甲酸二甲酯反应动力学的影响

研究了不同初始pH值、浊度与常见阴离子浓度等水质条件对UV/H2O2工艺降解邻苯二甲酸二甲酯(DMP)反应速率的影响,并进一步比较了去离子水和自来水中DMP的降解速率。结果表明,UV/H2O2对DMP的光降解过程符合一级反应动力学模型,不同水质条件对降解速率有不同程度的影响。酸性条件较碱性条件更有利于DMP降解;水的浊度大于7NTU时,光降解速率常数迅速下降;NO3-、Cl-、HCO3-等阴离子对DMP降解有抑制作用,且随离子浓度增大,抑制作用增强,3种离子对DMP光降解的抑制程度顺序为HCO3->NO3->Cl-。在5个30W低压汞灯照射下,当H2O2的浓度为20mg.L-1时,DMP在去离子水和自来水中光降解速率常数分别为0.0428min-1和0.0315min-1,自来水中的光降解速率常数较去离子水中的低,这可能是水中多种离子影响的结果。

水中无机阴离子对UV/H_2O_2降解LAS的影响及机理

研究了UV/H2O2工艺对直链烷基苯磺酸钠(LAS)的去除效果以及水中常见无机阴离子对LAS降解的影响和机理.结果表明,UV/H2O2工艺可以有效的去除水中LAS,光降解过程符合一级反应动力学模型.在H2O2投加量为8 mg.L-1,14 W低压汞灯照射下,LAS在蒸馏水和自来水中光降解速率常数分别为0.0180 min-1和0.0122 min-1;NO3-、Cl-、SO42-和HCO3-对LAS光降解有抑制作用,4种离子在浓度分别为5、10、15 mmol.L-1时,对LAS光降解的抑制程度均为HCO3->NO3->Cl->SO42-;随着离子浓度增大,抑制作用增强;自来水中的光降解速率常数低于蒸馏水中的光降解速率常数是由于水中多种离子影响的结果.

脱落酸对UV-C胁迫下小麦幼苗光合特性及抗氧化酶活性的影响

研究了UV-C辐射下短期和长期脱落酸(ABA)处理对小麦幼苗CO2同化作用、羧化效率、光合CO2响应以及抗氧化酶活性等的影响.结果表明,在无UV-C辐射情况下,短期和长期ABA处理能提高光合速率,比对照增加14·69%和20·46%,降低气孔导度,比对照降低14·74%和17·31%,但对胞间CO2浓度和羧化效率影响不大.当受到UV-C辐射时,光合速率、羧化效率、气孔导度和胞间CO2浓度逐渐降低.长期ABA处理变化最小,其次为ABA短期处理,对照降低最大.ABA处理能够提高小麦光合对CO2的响应,UV-C辐射抑制光合对CO2的响应.ABA处理能够提高小麦抗氧化酶(CAT、SOD、POD)活性而降低MDA含量.在UV-C辐射下,CAT活性先升高随后降低,在辐射处理1h时活性达最大值,ABA处理的SOD和POD活性先升高后降低,且ABA长期处理比短期处理增加明显,对照则逐渐降低.ABA处理可能通过提高小麦CO2同化作用和抗氧化酶活性增强对UV-C胁迫的抗性,且ABA长期处理比短期处理效果更明显.

增强UV-C辐射作用下小麦和豌豆幼苗光合响应及其相对抗性

以小麦和豌豆为材料,研究了UV-C辐射(波长<280nm)对叶片光合特性及抗氧化酶活性的影响.结果表明:UV-C辐射增强,可使豌豆叶片光合速率减弱,气孔导度、胞间CO2浓度、蒸腾速率和羧化效率明显降低,而对小麦叶片上述各项指标的影响则是先增加、后降低;在UV-C辐射下,豌豆的CO2补偿点逐渐升高,而小麦的CO2补偿点先降低、后升高.UV-C辐射除了使豌豆的POD活性和小麦的SOD活性逐渐降低外,其他抗氧化酶活性则呈先升高、后降低的变化趋势.小麦对短时间UV-C辐射的抗性比豌豆强,但随着UV-C辐射时间的延长,小麦和豌豆的抗氧化酶活性均降低,光合作用减弱.

1.54 mu m near-infrared photoluminescent and electroluminescent properties of a new Erbium (111) organic complex

The crystal structure of Er(PM)(3)(TP)(2) [PM = 1-Phenyl-3-methyl-4-isobutyryl-5-pyrazoloiie, TP = triphenyl phosphine oxide] was reported and its photoluminescence properties were studied by UV-vis absorption, excited, and emission spectra. The Judd-ofelt theory was introduced to calculate the radiative transition rate and the radiative decay time of 3.65 ms for the I-4(13/2) -> I-4(15/2) transition of Er3+ ion in this complex.

北五味子不同炮制品中的木脂素类成分

研究北五味子炮制前后其中木脂素类成分的变化。采用电喷雾质谱(ESI-MS)以及高效液相色谱(HPLC)分别对经过不同方法炮制后的北五味子中木脂素类成分进行研究。北五味子经过不同方法炮制后,并没有新成分的生成,只是木脂素类成分含量有不同程度的变化。并对不同的炮制方法进行了比较。该方法准确、可靠,为北五味子不同炮制品的质量评价提供了一定的科学依据。

麻黄炮制条件的ESI-MS法优化

ESI-MS was used to optimize the Ephedra sinica refinement. The ratio of honey to drug is 20/100, and the ratio of water to honey is 1/2. The toast temperature is 80 ℃, and the toast time is 2 h. The change of Ephedra sinica after processing was given.