Accumulation of Co in Yeast Cells under Metabolically Active Condition—Implication for Role of Yeast in Migration of Radioactive Co—

The accumulation and change in the chemical states of Co have been studied to elucidate the role of the yeast Saccharomyces cerevisiae in the migration of radioactive cobalt in the environment. The yeast was grown in a solution containing Co(II) ions, a carbon source, and essential elements (metabolically active condition). For comparison, an adsorption experiment of Co(II) ions on the yeast cells under resting condition without essential elements was performed. Time courses of Co concentration in the solution, in the cells, and chemical states of the accumulated Co were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), particle-induced X-ray emission (PIXE), and X-ray absorption fine structure (XAFS) analyses. The time courses of Co concentration in the solution showed that a higher amount of Co was accumulated by the yeast cells under the metabolically active condition than under the resting one. PIXE analyses showed the concurrent accumulation of Fe with Co accumulation under the metabolically active condition, suggesting the intracellular accumulation of Co. XAFS analyses showed that the k³-weighted extended-XAFS functions and the radial structural function of Co accumulated by the yeast cells under the metabolically active condition are similar to those under the resting condition, indicating that the chemical states of the accumulated Co were nearly the same between both conditions. These results indicate that the yeast performs better retardation of the migration of Co under the metabolically active condition than under the resting one.     

核分析相关技术用于上海市大气污染特征研究

本文研究了近年来上海市区和郊区大气气溶胶颗粒物的污染状况,采用的多种核分析方法及相关技术有质子激发X荧光分析(PIXE)、激光粒径谱仪(LPS)、同步辐射X射线吸收精细结构(XAFS)和扩展X射线吸收谱精细结构(EXAFS)分析等先进技术.充分发挥核分析技术高灵敏度、快速无损、多元素微量微区同时分析的优势,从大气颗粒物的形貌特征、粒径分布、质量浓度、元素浓度、化学价态等入手,对上海大气可吸入颗粒物PM23和PM1o展开多方位的综合研究.     

Chronological studies of tree-rings from the Amazon Basin using thick target PIXE and proton backscattering analysis

A tree-core sample (Aspidosperma obscurinervium, popular name: “pequiá marfim”) about 161 years old (cut in 1990), from the Ducke Reserve at the Amazon Basin, Manaus, Brazil was analyzed by PIXE (Particle Induced X-ray Emission) and proton backscattering in 136 different spots along its life. Twenty-two elements plus the density of the wood were measured (C, O, H, Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Co, Rb, W and Pb). Average C, O, and H results (49.77% ± 0.15%, 44.29% ± 0.14% and 5.95% ± 0.12%, respectively) compare well with literature values for the biomass in the Amazon region. The variability of trace elements along the tree rings showed important features that could be caused by modifications in the environment during the life of the tree. The well behaved variability of some trace elements (like K, P, Mn, Ca, etc.) seems to reflect the physiological response of the tree to external changes in the environment. The concentration of K varied from about 4 up to 2000 ppm in a given period of the life of the tree. The same period also shows important changes in the bulk composition and structure of the rings (e.g. C and density series). Multivariate statistical methods (cluster and factor analyses) were used for data interpretation, helping in the separation of periods of important transformations in the tree. The elemental time series is compared with historical records of regional development and with some global events that could possibly affect the tree. The period of maximum variation in the elemental concentrations appears to be related to the Brazilian rubber boom (1859–1912), responsible for several transformations in the Amazon region. In particular in the Manaus region, large development has occurred in the beginning of the 20th century, which are reflected in the results of this tree-core analysis.     

Analysis of atmospheric aerosols by particle-induced X-ray emission, instrumental neutron activation analysis, and ion chromatography

Particle-induced X-ray emission (PIXE), ion chromatography (IC), and occasionally also instrumental neutron activation analysis (INAA) were used in combination for the analysis of atmospheric aerosol samples that were collected on Nuclepore polycarbonate filters. A comparison of the results enabled us to evaluate the matrix effects (i.e., particle size effects) of the PIXE analysis for the light elements and to assess the water-solubility and/or speciation of a number of elements (e.g., S, K, Ca). Results are presented from several measurement campaigns at urban and forested sites in Europe, whereby PM10 or PM2.5 filter samples were taken. From the PIXE and IC results for a 2003 summer campaign at the K-puszta site in Hungary, it was estimated that organosulphates could be responsible for 20% of the total sulphur concentration and 30% of the organic aerosol in PM10. The comparison of the IC and PIXE data for K and Ca from the various sites indicated that most of the Ca was water-soluble (the mineral dust Ca was presumably mostly present as calcite, and perhaps also in part as gypsum); in contrast, for K, only half of it was typically water-soluble, indicating that it was to a large extent associated with insoluble mineral dust. Exceptions, with almost fully water-soluble K, were found for samples that were substantially impacted by biomass burning.     

全反射X荧光分析技术的应用

简要地介绍了全反射Ｘ荧光分析技术和一台小型全反射Ｘ荧光分析装置，这台装置的最低检出限对于Ｃｏ元素和Ｃｕ靶Ｘ光管激发下是７ｐｇ，对Ｓｒ元素，Ｍｏ靶是３０ｐｇ，对自来水、海洋动物、头发等进行了应用分析实验。     

乳腺肿瘤组织中的微量元素分析

用同步辐射X射线荧光(SR-XRF)技术分析了正常乳腺组织、良性乳腺肿瘤组织和乳腺癌组织中微量元素的种类、相对含量等.根据SR-XRF的结果,在这三种组织中微量元素的种类是相同的,但相对含量是不相同的,特别是正常组织和肿瘤组织中的Ca、Fe和Zn的差异相当明显.肿瘤组织中S、Cr、Mn、Ni、Cu和Se的相对含量与正常组织中含量具有正相关性,即肿瘤组织的含量相对于正常组织是增加的,而K和Ca则是负相关性.P在正常乳腺组织和良性乳腺肿瘤组织中的含量基本不变,但在癌变组织中略有下降.恶性肿瘤中的Fe和Zn是正相关性,而在良性肿瘤中则是负相关性.可见:正常、良性和癌变的乳腺组织中微量元素的相对含量是不同的,可以为乳腺癌的诊断提供有用信息.     

Trace element load in cancer and normal lung tissue

Samples of malignant and benign human lung tissues were analysed by two complementary methods, i.e., particle induced X-ray emission (PIXE) and total reflection X-ray fluorescence (TRXRF). The concentration of trace elements of P, S, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Se, Sr, Hg and Pb was determined in squamous cancer of lung tissue from 65 people and in the benign lung tumour tissue from 5 people. Several elements shows enhancement in cancerous lung tissue of women in comparison to men, i.e., titanium show maximum enhancement by 48% followed by Cr (20%) and Mn (36%). At the same time trace element concentration of Sr and Pb are declaimed by 30% and 20% in women population. Physical basis of used analytical methods, experimental set-up and the procedure of sample preparation are described.     

核分析技术在基础医学研究中的若干应用

应用同步辐射Ｘ荧光微探针（ＳＲ－ＸＭＦ）和扫描质子微探针（ＳＰＭ）技术研究了基础医学领域中与微量元素有关的几个课题。初步实验结果表明，具有高灵敏度、高分辨率和对样品损伤小的ＳＲ－ＸＭＦ和ＳＰＭ技术特别适合于元素含量低的细胞和生物组织样品，这些技术是研究元素的细胞生理学，从细胞水平探讨微量元素的生物学作用机理以及从微观角度阐明疾病的致病机理等方面有独特作用的新手段。     

Some aspects of statistical distribution of trace element concentrations in biomedical samples

Concentrations of trace elements in biomedical samples were studied using X-ray fluorescence (XRF), total reflection X-ray fluorescence (TRXRF) and particle-induced X-ray emission (PIXE) methods. Used analytical methods were compared in terms of their detection limits and applicability for studying the trace elements in large populations of biomedical samples. In a result, the XRF and TRXRF methods were selected to be used for the trace element concentration measurements in the urine and woman full-term placenta samples. The measured trace element concentration distributions were found to be strongly asymmetric and described by the logarithmic–normal distribution. Such a distribution is expected for the random sequential process, which realistically models a level of trace elements in studied biomedical samples. The importance and consequences of this finding are discussed, especially in the context of comparison of the concentration measurements in different populations of biomedical samples.     

脱氮硫杆菌的筛选及其对锶离子的矿化作用

放射性污染日益严重,其中锶污染作为土壤典型污染之一成为研究热点。土壤中存在着一些矿化菌,能够对锶离子进行矿化固定。本实验对从土壤中分离的3株脱氮硫杆菌的特性及其对Sr~(2+)的矿化行为进行了研究,发现该菌对1.0g/L模拟Sr~(2+)污染的去除率可达80%。扫描电子显微镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)等结果显示,矿化产物为硫酸锶。可见,利用脱氮硫杆菌治理土壤中Sr~(2+)污染具有可行性,该方法将会有一定应用前景。     

Element localisation in polymorphic fungi using the oxford scanning proton microprobe

Elemental concentrations and their distribution in different cell types of Ophiostoma ulmi were determined using the Oxford scanning proton microprobe. In all cell types i.e. germ-tubes and hyphae, K, P and S were major constituents and these, and other elements, were not distributed uniformly throughout the cells. In many cases, and especially for K and P, patterns of localisation could be correlated with vacuolation and/or a high cell solids content e.g. at germ-tube or hyphal tips. Other elements e.g. Cu and Fe appeared to be mainly located in the cytoplasm. Glutaraldehyde fixation appeared to induce some K loss from the cells although regions of K localisation were unaffected.     

Neutronic analysis of silicon carbide cladding accident-tolerant fuel assemblies in pressurized water reactors

In pursuit of a fully coherent X-ray free-electron laser(FEL), highly reflective Bragg crystals are used and will be used as a highly selective spectral filter in hard X-ray self-seeding FELs and X-ray FEL oscillators(XFELO), respectively. However, currently, when simulating self-seeding and XFELO, the three-dimensional effect of Bragg diffraction is not fully considered. In this paper, we derive a comprehensive solution for the response function of the crystal in Bragg diffraction. A three-dimensional X-ray crystal Bragg diffraction code, named BRIGHT, is introduced, which can be combined with other FEL-related codes, e.g., GENESIS and OPC. Performance and feasibility are assessed using two numerical examples,namely a self-seeding experiment for the linac coherent light source and XFELO options for Shanghai high repetition rate XFEL. The results indicate that BRIGHT provides a new and useful tool for three-dimensional modeling of FEL.     

源激发X射线荧光测定头发中Ca、Fe、Cu、Zn、Pb的方法优化

同位素源激发X射线荧光（XRF）已广泛应用于头发中的微量元素测定。中国原子能科学研究院曾经建立了源激发X射线荧光分析技术分析头发样品,Pb的检测限（LLD）约10μg/g。本工作在原来工作的基础上优化仪器参数,降低背景信号强度,提高了灵敏度,尤其是对Pb的灵敏度,使Ca、Fe、Cu、Zn、Pb的检测限分别达到19、1.2、1.1、0.62、1.1μg。首次采用V做内标元素,取样量为0.5g,仪器的短期稳定性相对标准偏差（RSD）为0.38%,长期稳定性相对标准偏差为0.98%。     

Accelerator-based trace element analysis of foods and agriculture products

An accelerator-based analytical method for measuring trace elements in foods and agricultural products was developed, optimized, validated and compared using reference standards. The method’s initial phase is a new, rapid and effective digestion process of a small mass analyte in an aqueous media containing H₂O₂. Digestion is initiated by radicals formed in water with pulsed UV (PUV) induced (laser) photolysis, which rapidly react with organic matter. After digestion, trace metals are pre-concentrated as carbamates and deposited as thin targets onto Teflon filters. Conventional particle induced X-ray emission (PIXE) or X-ray fluorescence (XRF) methods are then used to analyze elements in the sample. When foods and other agricultural commodities (i.e., soils, feeds) are analyzed, the combined method named pulsed UV (PUV)/PIXE results in enhanced detection of trace elements such as Fe, Co, Ni, Cu, Zn and Pb at ∼1 mg/kg (1 ppm) levels, without lengthy, acid-based digestions. It provides improvements in digestion kinetics and processing time enhancing analytical sensitivity and element recovery. Precision and recovery yields were confirmed with food reference standards. The analysis of edible foods from contaminated agricultural areas is also reported.     

Quantitative PIXE analyses of ferromanganese oxide deposits from different locations of the Indian Ocean and a deposit from the Pacific Ocean

The present studies on ferromanganese nodules and encrustations from the Indian Ocean and a sediment from the Pacific ocean, were carried out to investigate the role of Mn and Fe in the uptaking of various trace elements from seawater. The Indian Ocean samples comprised eight iron rich ferromanganese nodules and four ferromanganese encrustations, out of which two are from Mid Indian Ocean Ridge (MIOR) and one each from Afanasiy Nikitin seamount and topographically elevated region. The Pacific Ocean sample was a metalliferrous sediment from Lau Basin. The Proton Induced X-ray Emission (PIXE) measurements were carried out on all the samples using 3 MeV proton beam from a 3 MV Pelletron accelerator for quantitative multielemental analysis. The spectral data were analysed using GUPIX software. Quantitative estimate of nearly 21 elements, e.g., K, Ca, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Sr, Y, Zr, Nb, Mo, Ba, Tl, Pb, and Bi have been made. The classification of the deposits into hydrogenous and hydrothermal types was carried out on the basis of their Mn/Fe ratios and subsequently, the distribution of various minor and trace elements were studied. The growth rate of these deposits are estimated. The findings show that, the concentrations of various elements in hydrogenous deposits are higher compared to that in hydrothermal ones. The reason for this behaviour is attributed to suitable physico-chemical oceanic conditions prevailing at the depositional sites and the growth rate of these deposits. The variation in the concentrations of Co, Ni and Cu is shown to be dependent on ocean depth. It was found that the Co content is significantly high for the deposit from the Afanasiy Nikitin seamount. It has also been shown and discussed that the hydrothermal processes seem to be more controlling in the uptake of V and As than the hydrogenous processes.     

On some “pseudosilicides” having the cubic AB5 structure

X-ray and metallographic investigations indicated that in the binary intermetallic compounds UNi₅ and ZrNi₅ one nickel atom may be substituted by combinations of some elements of the IIIa-Va and IIb-VIa groups, i.e. that “pseudosilicon” can play the role of a substituent in some AB₅ phases. Single phase alloys were obtained in the systems of the general formula UNi₄Y (Y = In + As, In + Sb, Zn + Te, Cd + Te) and ZrNi₄Y (Y = In + As, In + Bi, Zn + Te, Cd + Te). The homogeneity regions (ratio of the constituent elements of the Y component) were also determined. In all the systems investigated so far, at the equiatomic compositions of the substituents (VEC = 4), contraction of the unit cell parameters and an increase of microhardness values were observed. Intensity calculations showed that the substitution takes place in positions 4(c) in the space group F4̄3m. The resulting structures may also be considered as superlattice of the MgSnCu₄ type. The stability of these phases is discussed in terms of relative atomic sizes and valence electrons concentrations.     

A spray technique for preparing uniform large-area PIXE calibration standards from aqueous solutions

We describe a procedure for preparing reference standards that can be used to calibrate PIXE spectra of aerosol deposits collected on suitable backing films made, for example, of synthesised polymers (polypropylene, polycarbonate etc.) or chemically modified biopolymers (e.g., cellulose actetate). Aqueous solutions of well defined concentration were prepared from metal salts. The solutions were spray-deposited on cellulose acetate backings using a nebuliser. Lateral uniformity of the deposited layer over areas ranging from several mm to several cm was accomplished by raster scanning the table on which the backing was mounted. By optimising the experimental parameters, deposition could be accomplished without any detectable wetting of delicate substrates like paper. The areal density of the deposited material was calculated from the concentration of the solute, the volume of the consumed solution and the raster scanned area. The reference standards were analysed by PIXE using an external beam chamber backfilled with helium. The Si(Li) based detection system contained a thin funny filter so that X-ray spectra could be measured down to 1 keV. The proton energy on impact was 1.1 MeV. This relatively low probe energy has the advantage of producing favourable elemental X-ray peak heights relative to the bremsstrahlung-background, notably at energies between 2 and 7 keV. Under the same conditions sufficiently high X-ray yields were achieved for heavy elements like Zn and Pb. Using large area beams, bombardment-induced stress in the backing films could be kept at a low level so that very reproducible background spectra were obtained. Hence a straightforward background subtraction routine could be employed. Sensitivities were determined for 23 elements ranging from Na to Pb. Advantages and problems associated with the different metal salts are discussed briefly.     

用质子激发X荧光分析技术鉴别玉器种类

质子激发Ｘ荧光分析中以测定玉器的主量、次量及微量元素的成分和含量,因而可以将那些外形及颜色相近的玉器因其化学组分的不同而清楚地分开,并得知其真实的材料种类。对于主要化学组分一致的同类玉器,如果产于不同的地方,则由于其成矿地区地球化学环境的不同,它们的微量元素种类及含量也将有所不同,因而这一方法也可用来判定玉器的产地。     

Analysis of metal alloys by Rayleigh to Compton ratios and X-ray fluorescence peaks in the 50 to 122 keV energy range

A method for nondestructive analysis of metal alloys able to explore inner strata of material up to ? 100 μm is described. The method employs two or more low-energy γ-ray radioactive sources in a backscattering geometry (Θ = 135°). The ratio $\text{R}\text{C}$ between elastic (R) and inelastic (C) scattered components together with the ratio $\text{I}\text{C}$ between the X-ray fluorescence intensity lin higher-Z elements (e.g. Pb in a bronze matrix or Au in a gold matrix) and the Compton (C) is taken into account in order to evaluate the main element weight fractions of the alloy.The calibration coefficients for a four component bronze alloy were determined by multivariate analysis on standard bronze samples.The precision on each of the weight fraction obtained was equal or better than some percent in a measuring time of ? 1000 s.     

Synchrotron radiation X-ray fluorescence analysis on altered mineral muscovite in gold deposit

Synchrotron radiation X-ray fluorescence (SRXRF) microprobe was used to ananlyse altered mineral muscovite and its surrounding feldspar in Yuerya gold deposit. The major, minor and trace elements of the two minerals were detected and analyzed. SRXRF analysis showed that the Yuerya muscovite had a complex chemical composition. containing K, Fe, Ca, Ti, Cr, Mn, Co, Cu, Zn and many trace or ultra-trace elements. Since muscovite resulted from the alteration of hydrothermal ore fluid acting on feldspar (plagioclase), the difference of chemical composition between the two minerals shows the components of ore fluid, which are characterized by the enrichment of alkaline and alkaline-earth metal elements K, Ca and ore-associated elements Fe, Cu, Zn. And gold. silver and platinum, invisible under microscope, were detected in some areas of muscovite but not found in feldspar. Especially platinum, a mantle material is rarely seen in the earth crust but now found in the gold deposit of magmatic sources; its appearance approves the idea of mantle flux participating in the gold mineralization, which suggests that the tectonic event controlling gold mineralization in the Yuerya district is a mantle phenomenon.