薄膜样品的制作与均匀度测定

液滴法[1]是制作薄膜样品的最简单方法,本文介绍了使用该方法制作薄膜样品的具体步骤.由于样品在自然蒸发过程中具有结晶效应,使得最终形成的样品极不均匀.如果使用这种样品刻度系统的灵敏度曲线,样品的不均匀性会引起严重的实验误差.利用使用X光会聚透镜的XRF系统[2]形成的小束斑,可对样品的均匀度进行分析.另外文中给出了在使用此种样品刻度系统灵敏度曲线时,消除样品不均匀性引起误差的方法.     

生物矿化合成木材-SiO2复合材料的XPS分析

利用生物矿化原理制备木材—SiO2复合材料,采用溶胶—凝胶法制备硅溶液,用不同质量分数的硅溶液对喜树进行浇灌和滴注试验。经过1个月的试验得到样品,利用光电子能谱仪(XPS)分析素材和SiO2复合材样品中硅、碳的质量比,证实喜树成功吸收硅元素,并且存活,植株根茎附近生长较好,枝叶较多,顶部附近枝叶较少。比较浇灌、滴注2种方法:①浇灌过程相对简单,树木对硅的吸收相对较少;使用质量分数越高的药品对树木进行浇灌,树木对硅的吸收越好。②滴注过程相对复杂,树木对硅的吸收相对较多;使用质量分数越高的药品进行滴注,树木对硅的吸收越好;但吸收不均匀,呈滴注孔口附近往树梢方向减少趋势。前期研究结果表明,对树木进行浇灌和滴注,药品硅的质量分数过高树木会死亡,过低则达不到要求,因此,最佳质量分数配制还有待于进一步研究确定。总的来说,利用生物矿化原理模拟木材—SiO复合材是可行的。     

X射线荧光光谱法快速检测原料公干鱼中的镉

旨在建立一种基于X射线荧光光谱法快速检测原料公干鱼(原料鱼)中镉的方法。应用X射线荧光光谱法快速检测原料鱼初始样及干燥样中的镉含量,对快速检测与标准检测结果的相关性进行了分析;考察了对原料鱼进行快速干燥处理的可行性;采用原料鱼的标准测定值对X射线荧光光谱仪进行校正后,考察了快速检测方法的精密度、检测限、准确度等性能参数。结果表明:X射线荧光光谱法能准确测定原料鱼干燥样中的镉,检测限达0.088 mg/kg,线性范围为0.088~1.286 mg/kg,相对标准偏差低于10%。该快速检测方法测定单个样品只需40 min左右,可满足现场对原料鱼中镉的快速测定要求,为防控原料鱼食品中镉超标风险提供了一种高效的筛查手段。     

A pollen extender medium technology for seedless watermelon production by pollination with soft X-ray irradiated pollen

The inactivation of pollen by soft X-ray irradiation and subsequent artificial pollination are time-intensive practices used in the production of seedless watermelons (Citrullus lanatus L.). Watermelon generally has a lot of staminate flowers; however, they only have a small amount of pollen. Watermelon pollen cannot be used in pollination under the present situation. Therefore, the objective of this study was to determine which is the most effective pollen extender medium for cultivation of watermelon with soft X-ray irradiated pollen. In this experiment, ‘Agar,’ ‘Marriage powder,’ and ‘Sekishoshi’ (Lycopodium dyed red with safflower pigment) were used as extender media with soft X-ray irradiated pollen at equal or twice the weight of the pollen. When ‘Sekishoshi’ was used as an extender medium, fruit set was very low. A lot of deformed fruit was produced when agar was used with the pollen. On the other hand, when ‘Marriage powder’ was used in equal proportions with the pollen, fruit set was about 70% and, moreover, Brix was high. Thus, the mixture of ‘Marriage powder’ with an equal amount of pollen was the best for use in actual cultivation. We conclude, then, that soft X-ray irradiated pollen in an extender medium can be effectively adapted for producing seedless watermelons.     

X射线无损检测技术在农产品品质评价中的应用

近年来,无损检测技术在农业中得到了广泛的应用.X射线检测作为无损检测的重要技术手段,在农产品品质检测与评价中发挥了重要的作用.为此,综述了国内外在X射线检测技术应用于农产品品质检测方面的研究进展;阐明了X射线检测技术测定的基本原理;介绍了其在果品水分测定、农产品内部病虫害检测、外观品质检测以及异物检测等方面的典型应用实例;并展望了X射线检测技术在农产品检测中的应用前景.     

报废汽车回收X射线分选技术研究进展与应用

介绍了X射线分选的具体原理,指出了目前X射线分选存在的问题,综述了国内外报废汽车回收X射线分选的研究进展与相关设备应用现状,展望了X射线分选技术的发展趋势.     

In Vitro Anticancer and Cancer-Preventive Activity of New Triterpene Glycosides from the Far Eastern Starfish Solaster pacificus

Sea stars or starfish (class Asteroidea) and holothurians or sea cucumbers (class Holothuroidea), belonging to the phylum Echinodermata (echinoderms), are characterized by different sets of glycosidic metabolites: the steroid type in starfish and the triterpene type in holothurians. However, herein we report the isolation of eight new triterpene glycosides, pacificusosides D–K (1–3, 5–9) along with the known cucumarioside D (4), from the alcoholic extract of the Far Eastern starfish Solaster pacificus. The isolated new compounds are closely related to the metabolites of sea cucumbers, and their structures of 1–3 and 5–9 were determined by extensive NMR and ESIMS techniques. Compounds 2, 5, and 8 have a new type of tetrasaccharide chain with a terminal non-methylated monosaccharide unit. Compounds 3, 6, and 9 contain another new type of tetrasaccharide chain, having 6-O-SO₃-Glc as one of the sugar units. The cytotoxic activity of 1–9 against non-cancerous mouse epidermal cells JB6 Cl41 and human melanoma cell lines SK-MEL-2, SK-MEL-28, and RPMI-7951 was determined by MTS assay. Compounds 1, 3, 4, 6, and 9 showed potent cytotoxicity against these cell lines, but the cancer selectivity (SI > 9) was observed only against the SK-MEL-2 cell line. Compounds 1, 3, 4, 6, and 9 at the non-toxic concentration of 0.1 μM significantly inhibited neoplastic cell transformation of JB6 Cl41 cells induced by chemical carcinogens (EGF, TPA) or ionizing radiation (X-rays and UVB). Moreover, compounds 1 and 4 at the non-toxic concentration of 0.1 µM possessed the highest inhibiting activity on colony formation among the investigated compounds and decreased the colonies number of SK-MEL-2 cells by 64% and 70%, respectively. Thus, triterpene glycosides 1 and 4 can be considered as prospective cancer-preventive and anticancer-compound leaders.     

Quantifying the impact of microbes on soil structural development and behaviour in wet soils

There is evidence that microbial populations play an important role in altering soil pore geometry, but a full understanding of how this affects subsequent soil behaviour and function is still unclear. In particular the role of microorganisms in soil structural evolution and its consequence for pore morphological development is lacking. Using a combination of bio-chemical measurements and X-ray Computed Tomography (CT) imaging, a temporal comparison of microscale soil structural development in contrasting soil environments was made. The aim was to quantify the effect of microbial activity in the absence of other features likely to cause soil deformation (e.g. earthworms, roots etc.) on soil structural development in wet soils, defined by changes in the soil porous architecture i.e. pore connectivity, pore shape and pore volume during a 24 week period. Three contrasting soil textures were examined and changes compared between field soil, sterilised soil and a glucose enhanced soil treatment. Our results indicate that soil biota can significantly alter their microhabitat by changing soil pore geometry and connectivity, primarily through localised gaseous release. This demonstrates the ability of microorganisms to modify soil structure, and may help reveal the scope by which the microbial-rich rhizosphere can locally influence water and nutrient delivery to plant roots.     

犬结肠双重造影术

对20只本地成年犬进行了结肠双重造影试验.建立了犬结肠双重造影的实施方法.造影剂的剂量以60%(w/v)硫酸钡浆100～200mL、空气100～150mL为宜.利用X线摄片记录了结肠双重造影像,并描述和分析了影像效果.