HPLC测定河套大黄中的土大黄苷含量

从河套大黄中分离纯化出活性成分土大黄苷,作为自制的标准品,利用KromasilTM C(18)(250 mm×4.6 mm I.d.,5μm)反相色谱柱,以V(甲醇):V(乙腈):V(水)=35:5:60为流动相,以320mm为检测波长,对河套大黄中土大黄苷进行测定.土大黄苷在0.427～4.190μg范围内与峰面积呈良好线性关系(r=0.9994),平均回收率为99.12%.该方法为河套大黄的质量控制奠定了基础.     

大孔吸附树脂结合酶解法分离纯化虎杖中白藜芦醇的研究

研究了大孔吸附树脂结合酶解法提取和纯化虎杖中白藜芦醇的方法,采用HPLC法测定虎杖中白藜芦醇的含量,考查了β-糖苷酶对虎杖药材酶解前后白藜芦醇含量的变化,并经静态吸附考察了4种树脂,最后确定以H1020作为提取分离白藜芦醇的树脂.此树脂吸附量较高,脱附容易,有利于得到质量较好的白藜芦醇产品,经该树脂吸附解吸,饱和吸附量可达51.4mg/g,解吸率达92.5%.大孔树脂分离纯化白藜芦醇的含量可达71.5%,而上柱前粗提物中白藜芦醇含量为8.71%,说明采用本法分离纯化虎杖中白藜芦醇是可行的.     

Risk arbitrage in the Nikkei put warrant market of 1989–1990

This paper discusses the Nikkei put warrant market in Toronto and New York during 1989–1990. Three classes of long term American puts were traded which when evaluated in yen are ordinary, product and exchange asset puts, respectively. Type I do not involve exchange rates for yen investors. Type II, called quantos, fix in advance the exchange rate to be used on expiry in the home currency. Type III evaluate the strike and spot prices of the Nikkei Stock Average in the home currency rather than in yen. For typically observed parameters, type I are theoretically more valuable than type II which in turn are more valuable than type III. In late 1989 and early 1990 there were significant departures from fair values in various markets. This was a market with a set of complex financial instruments that even sophisticated investors needed time to learn about to price properly. Investors in Canada were willing to buy puts at far more than fair value based on historical volatility. In addition, US investors overpriced type II puts fixed in dollars rather than the type I's in yen. This led to cross border and US traded (on the same exchange) low risk hedges. The market's convergence to efficiency (that is, all puts priced within transaction cost bands) took about one month after the introduction of the US puts in early 1990 leading to significant profits for the hedgers.     

Nouveau Modele d'Electrode Modifiee a Base de Carbone et de Polymere

Abstract

A new type of modified electrode is proposed, based on the thermosealing of carbon and a polymer in different proportions. The mode of preparation and the performances of this new model of polymer electrode are described in details. The potential range is larger than with other electrodes, particularly in the anodic range. Some performances realized on the behaviour of pharmaceutical compounds are described.     

瓯柑愈伤组织的玻璃化法超低温保存研究

采用玻璃化法对瓯柑愈伤组织进行超低温保存研究.瓯柑愈伤组织在含5%二甲亚砜(DMSO)的MS培养基上预培养5 d,室温下60%PVS2预处理20 min,然后用100%PVS2于0℃处理40 min,投入液氮(LN)保存,24h后在40℃水浴中迅速化冻,再用1.2 mol/L蔗糖培养液洗涤3次.用氯化三苯四氯唑(TTC)法检测,其存活率可达85.62%.冻后的愈伤组织转移到MS+6-BA 0.5 mg/L继代培养基上,在黑暗中培养生长,存活率可达76.32%.分析讨论了瓯柑愈伤组织玻璃化法超低温保存中存在的一些问题及意义,并对其前景进行了展望.     

杨梅缺硼症状与硼肥施用技术研究

为矫治杨梅缺硼症状，采用了喷施和土施硼肥技术。调查和试验结果表明，杨梅硼元素缺乏的典型生理症状为叶小、枝梢丛生、枯梢、花量少，且不结果或很少结果。喷施0，2％硼砂液或0．2％硼砂 0．5％尿素液能明显矫治杨梅缺硼症状，改善春、夏两梢生长指标，提高坐果率，从而提高单株产量。土施硼肥也能取得较好的矫治效果，施用量以硼砂100g／株为佳；同时，土施处理在生产实际中还表现出良好的后续效应。     

Two new flavonoid diglycosides from Cephalotaxus sinensis

Two new acetylated flavonoid diglycosides, scutellarein-5-O-[a-L-rhamnopyranosyl-(1→ 4)-b-D-6-O-acetylglucopyranoside] (1), apigenin-5-O-[a-L-rhamnopyranosyl-(1→2)-b-D-3,6-di-O-acetylglucopyranoside] (2), were isolated from the leaves of Cephalotaxus sinensis. Their structures were determined by chemical and spectroscopic methods including HR-FAB-MS, 1H–1H COSY, HSQC and HMBC experiments.     

Analysis of the volatile oil from the stem of Acanthopanax Senticosus (Rupr. et Maxim.) harms with several hyphenated methods of chromatography

Gas chromatography/quadrupole mass spectrometry (GC/qMS), gas chromatography/Fourier transform infrared spectrometry (GC/FTIR) and gas chromatography/orthogonal acceleration time-of-flight mass spectrometry (GC/oaTOFMS) were applied to analyze the volatile oil from the stem of Acanthopanax Senticosus (Rupr. et Maxim.) Harms. Based on the mass spectra search function of GC/qMS with the aid of the discriminability of the geometrical isomer by GC/FTIR and the ability to determine the accurate mass charge ratio (m/z) by GC/oaTOFMS, 68 GC eluants were identified successfully. Compared with the results obtained by GC/qMS only, the analytical results obtained by these hyphenated methods of gas chromatography are more credible. __________ Translated from Chinese Journal of Chromatography, 2005, 23(2)(in Chinese)     

Structure-Activity Relationship of Insecticidal Steroids. IV. 3β-Chlorosubstituted Derivatives of Cholesterol and β-Sitosterol

The toxicity of 3-chlorosteroids 1-8 for colorado beetle (Leptinotarsa decemlineata Say.) larvae was studied by a contact-intestinal method. The most active insect growth and development regulators of the studied compounds are 3-chlorocholest-5-ene (1a), 3-chloro-5,6-diol 6-formate (3b), 3-chloro-7-hydroxy-6-ketone (4a), and 3-chloro-5-bromo-⁴-6-ketone (8).