用于测量农药残留的小麦酯酶的选择

为研制探测农药残留的生物传感器，研究了农药乐果[O,O-二甲基S－（N－甲基胺基甲酰甲戎）二硫代磷酸酯]对各种小麦植物酯酶的抑制，从小麦中提取植物酶，以农药乐果为抑制剂，采用分光光度法研究了乐果对各种小麦酯酶活性的影响；研究显示，不同品种小麦酯酶对农药乐果的敏感度不同，在所研究的品种中，豫麦39和小麦周9对乐果较敏感，研究结果说明了选择小麦酶源的必要性。     

On the determination of crystallinity and cellulose content in plant fibres

A comparative study of cellulose crystallinity based on the sample crystallinity and the cellulose content in plant fibres was performed for samples of different origin. Strong acid hydrolysis was found superior to agricultural fibre analysis and comprehensive plant fibre analysis for a consistent determination of the cellulose content. Crystallinity determinations were based on X-ray powder diffraction methods using side-loaded samples in reflection (Bragg-Brentano) mode. Rietveld refinements based on the recently published crystal structure of cellulose Iβ followed by integration of the crystalline and amorphous (background) parts were performed. This was shown to be straightforward to use and in many ways advantageous to traditional crystallinity determinations using the Segal or the Ruland–Vonk methods. The determined cellulose crystallinities were 90–100 g/100 g cellulose in plant-based fibres and 60–70 g/100 g cellulose in wood based fibres. These findings are significant in relation to strong fibre composites and bio-ethanol production.     

10MeV 25KW industrial electron LINAC

A 10MeV 25KW plus class electron LINAC was developed for sterilisation of medical devices. The LINAC composed of a standing wave type single cavity prebuncher and a 2m electro-plated travelling wave guide uses a 5MW 2856MHz pulse klystron as an RF source and provides 25KW beam power at the Ti alloy beam window stably after the energy analysing magnet with 10MeV plus-minus 1 MeV energy slit. The practical maximum beam power reached 29 KW and this demonstrated the LINAC as one of the most powerful S-band electron LINACs in the world. The control of the LINAC is fully automated and the “One-Button Operation” is realised, which is valuable for easy operation as a plant system. 2 systems have been delivered and are being operated stably.     

Improved Extraction Method and Chromatographic Separation of Ginsenosides from Ginseng Roots,Leaves and Ginseng Drug Preparations

A new extraction method for ginsenosides from ginseng roots, ginseng leaves and ginseng drug preparations by Sep-Pak C₁₈ cartridges has been studied. Ginsenoside extraction by Sep-Pak cartridges is a rapid, efficient, reproducible method. In addition, the extracts were analyzed by high performance thin layer chromatography (HPTLC) and reverse phase high performance liquid chromatography (HPLC). The major components of ginseng saponins were effectively separated using an ODS-120T column.     

植物育种途径改善人类的铁,锌营养

概括了铁、锌与人体健康的关系，铁、锌的食物来源及生物有效性，并简要地论述了通过植物育种改善人类铁、锌营养的农业效应、经济效益以及有关这方面的研究进展。     

Analysis of non-organic elements in plant foliage using polarised X-ray fluorescence spectrometry

An X-ray fluorescence (XRF) method for the rapid and non-destructive analysis of 30 non-organic elements in plant leaves over five orders of magnitude concentration from several percentage of dry weight to sub-milligram per kilogram, is described. There is a growing need for a simple method of monitoring non-organic trace elements in plant material, especially those which accumulate in soils with application of fertilisers, both inorganic and biosolids. Earlier attempts to use XRF for the analysis of plant material suffered from sensitivity loss due to the high background of organic matrices caused by scattering of the X-ray source. We overcome this by using polarised X-ray sources in a Cartesian geometrical arrangement with sample and energy dispersive detector (EDPXRF), a configuration which can achieve an order of magnitude reduction in background compared with unpolarised sources. Further sensitivity gains are made using a high power tube as a source of primary X-rays and for some analytes employing secondary targets for near-monochromatic excitation. Sample preparation is simple involving only pulverising and briquetting of dried samples. Accuracy is evaluated by comparing data obtained for the suite of NIST plant leaf samples (NIST 1515 apple leaves, NIST 1547 peach leaves, NIST 1570a spinach leaves, NIST 1573a tomato leaves and NIST 1575a pine needles) and tobacco leaf standards CTA-OTL-1 and CTA-VTL-2. The data compare well over the whole concentration range and the method provides a rapid analytical tool for monitoring potentially toxic trace elements in all types of foliage with adequate sensitivity for many purposes.     

植物多酚在高分子材料中的应用

植物多酚类物质又叫单宁,是一类多羟基酚类化合物,具有良好的生物相容性和可降解性;由于多元酚的结构赋予了一系列独特的性质.植物多酚不但可以与醛类物质发生缩聚反应,还可以通过氢键、疏水键或者共价键与众多高分子化合物接枝、共聚或共混制备出新型的功能高分子材料.基于文献,对植物多酚在高分子材料,比如:聚氨酯、酚醛树脂、聚酯和一些天然高分子中的应用,如:增加高分子材料的抗菌、可降解以及抗氧化性等性能进行了综述.     

Optimization of selenium determination in plant samples by hydride generation and axial view inductively coupled plasma atomic emission spectrometry

The use of hydride generation coupled with axial view inductively couple plasma atomic emission spectrometry was presented for the determination of selenium in plant samples. The chemical factors affecting potentially the hydride generation efficiency (hydrochloric acid, sodium borohydride and sodium hydroxide concentrations) were assessed through investigation of chemical interference, accuracy and repeatability. The accuracy of measurements was not affected by elements present in high concentration in the plant matrix (K, Ca, Mg, and P). No interference was also observed with transition metals. Using a real sample (maize) with standard additions, decreases of recoveries were sometimes observed for 0.1% (m/v) NaOH, and attained 13.8% in the most unfavourable case. The final accuracy of the method was verified by using two certified reference materials: CRM 402 (white clover) and CRM 279 (sea lettuce). No statistically significant differences were obtained between the measured concentrations and the certified values. The optimized method was found sensitive (detection limit 0.15 μg l⁻¹), reliable and repeatable (R.S.D. between 1.3% and 4.0%).     

Glycosidases of turnip leaf tissues

Four myrosinase (β-thioglucosidase EC. 3.2.3.1) and seven disaccharase (β-fructofuranosidase, EC. 3.2.1.26) isoenzymes were isolated from turnip leaves. The most active enzymes were isolated in pure form. Myrosinase and disaccharase mol wt was 62.0 × 10³ and 69.5 × 10³ dalton, respectively, on the basis of gel filtration on Sephadex G-200. Myrosinase pH profile showed high activity between pH 5 and 7 with the optimum at pH 5.5. The purified enzyme was heat-stable for 60 min at 30°C with only loss of 24% of activity. Its activity is strongly inhibited (100%) by Pb²⁺, Ba²⁺, Cu²⁺ and Ca²⁺ ions, and activated (70%) by EDTA at 0.04M. The pure enzyme failed to hydrolyze amylose, glycogen, lactose, maltose, and sucrose. TheK _m andV _max values of myrosinase using sinigrin as specific substrate was 0.045 mM and 2.5 U, respectively. The maximal activity of disaccharase enzyme was obtained at pH 4–5 and 35–37°C. The enzyme was heat-stable at 30°C for 30 min with only 10% loss of its activity. Its activity is strongly activated (70–240%) by Ca²⁺, Ba²⁺, Cu²⁺, and EDTA at 0.01M. The enzyme activity is specific to the disaccharide sucrose and failed to hydrolyze other disaccharides (maltose and lactose). TheK _m andV _max of disaccharase were 0.123 mM and 3.33 U, respectively.