Micro-PIXE investigation of bean seeds to assist micronutrient biofortification

This study compares the distribution and concentrations of micro- and macronutrients in different bean cultivars with the aim of optimizing the biofortification, a sustainable approach towards improving dietary quality. Micro-PIXE was used to reveal the distribution of Fe, Zn, Mn, Ca, P, S in seeds of common beans (Phaseolus vulgaris) and runner beans (Phaseolus coccineus). Average concentrations of elements in different tissues were obtained using ICP-AES. The highest concentrations of Zn in the studied beans were found in the embryonic axis, but an increased concentration of this element was also detected in the provascular bundles of the cotyledons. The first layer of cells surrounding provascular bundles accumulated high concentrations of Fe, while the next cell layer had an increased concentration of Mn. The analysis showed that the provascular bundles and the first cell layers surrounding them could have a significant role in the storage of important seed micronutrients - Zn, Fe, and Mn. This information has important implications for molecular biology studies aimed at seed biofortification.     

Application of micro-PIXE,MRI and light microscopy for research in wood science and dendroecology

Beech (Fagus sylvatica L.) branches were topped and after five months the wound response was analyzed by PIXE, 3D-MRI and light microscopy. From freshly cut and deeply frozen sample 30 μm thick longitudinal-radial tissue sections were prepared for anatomical investigations and micro-PIXE analysis. Light microscopy revealed the structural response to wounding, i.e. occurrence of the reaction zone between the exposed and dehydrated dead tissue and healthy sound wood. The reaction zone was characterized by tylosis in vessels and accumulation of colored deposits in parenchyma cells, fibres and vessels. 3D MRI of a parallel sample showed that the moisture content in the reaction zone was three times higher than in normal healthy wood. Micro-PIXE mapping at margins of compromised wood in beech revealed an increased concentration of potassium in the reaction zone. The increase in the calcium concentration was associated with the dehydrated tissue adjacent to reaction zones.In addition, micro-PIXE was used to determine the elemental distribution in annual tree rings. This may be relevant for retrospective assessment of environmental pollution in wood by measuring yearly increments as a biomonitoring tool. The analysis of European larch (Larix decidua Mill.) wood revealed a high similarity between optical characteristics (i.e. late versus earlywood) and elemental (e.g. Cl, K, Ca, Mn, Zn) distribution.     

Elemental analysis of edible grains by micro-PIXE: Common buckwheat case study

The aim of this study was the adaptation of the micro-PIXE method for analysis of nutritionally relevant heavy elements in different tissues of the grain of common buckwheat (Fagopyrum esculentum), as a representative nutritionally interesting grain food source. At 57% of the buckwheat grain biomass, the endosperm was a modest nutrient source when compared to the cotyledons, at 17% of the biomass. These latter contained high concentrations of trace elements, representing 91% of the total grain Zn, 87% for P, 70% for S, 62% for Mg, 60% for K, 54% for Cu, 53% for Mn and 35% for Fe. The husk provided storage for 85% of the total Ca, 84% for Al, 83% for Si, 76% for Cl, 69% for Ti and 46% for Fe. Knowledge on these preferential elemental constitutions of the different grain tissues makes the possibility of designing target products with nutritionally optimal constitution more feasible. These data represent a basis for a more targeted approach to nutritional improvement of grains intended for human consumption.     

Evaluation of elemental status of ancient human bone samples from Northeastern Hungary dated to the 10th century AD by XRF

The present study is a multielemental analysis of bone samples belonging to skeletal individuals originating from two contemporaneous (10th century AD) cemeteries (Tiszavasvári Nagy-Gyepáros and Nagycserkesz-Nádasibokor sites) in Northeastern Hungary, using the XRF analytical technique. Emitted X-rays were detected in order to determine the elemental composition of bones and to appreciate the possible influence of the burial environment on the elemental content of the human skeletal remains. Lumbar vertebral bodies were used for analysis. Applying the ED(P)XRF technique concentration of the following elements were determined: P, Ca, K, Na, Mg, Al, Cl, Mn, Fe, Zn, Br and Sr. The results indicated post mortem mineral exchange between the burial environment (soil) and bones (e.g. the enhanced levels of Fe and Mn) and referred to diagenetic alteration processes during burials. However, other elements such as Zn, Sr and Br seemed to be accumulated during the past life. On the basis of statistical analysis, clear separation could not be observed between the two excavation sites in their bone elemental concentrations which denoted similar diagenetic influences, environmental conditions. The enhanced levels of Sr might be connected with the past dietary habits, especially consumption of plant food.     

Evaluation of specimen preparation techniques for micro-PIXE localisation of elements in hyperaccumulating plants

Hybanthus floribundus subsp. floribundus, a rare Australian Ni-hyperaccumulating shrub and Pityrogramma calomelanos var. austroamericana, an Australian naturalized As-hyperaccumulating fern are promising species for use in phytoremediation of contaminated sites. Micro-proton-induced X-ray emission (μ-PIXE) spectroscopy was used to map the elemental distribution of the accumulated metal(loid)s, Ca and K in leaf or pinnule tissues of the two plant species. Samples were prepared by two contrasting specimen preparation techniques: freeze-substitution in tetrahydrofuran (THF) and freeze-drying. The specimens were analysed to compare the suitability of each technique in preserving (i) the spatial elemental distribution and (ii) the tissue structure of the specimens. Further, the μ-PIXE results were compared with concentration of elements in the bulk tissue obtained by ICP-AES analysis.In H. floribundus subsp. floribundus, μ-PIXE analysis revealed Ni, Ca and K concentrations in freeze-dried leaf tissues were at par with bulk tissue concentrations. Elemental distribution maps illustrated that Ni was preferentially localised in the adaxial epidermal tissues (1% DW) and least concentration was found in spongy mesophyll tissues (0.53% DW). Conversely, elemental distribution maps of THF freeze-substituted tissues indicated significantly lower Ni, Ca and K concentrations than freeze-dried specimens and bulk tissue concentrations. Moreover, Ni concentrations were uniform across the whole specimen and no localisation was observed.In P. calomelanos var. austroamericana freeze-dried pinnule tissues, μ-PIXE revealed statistically similar As, Ca and K concentrations as compared to bulk tissue concentrations. Elemental distribution maps showed that As localisation was relatively uniform across the whole specimen. Once again, THF freeze-substituted tissues revealed a significant loss of As compared to freeze-dried specimens and the concentrations obtained by bulk tissue analysis.The results demonstrate that freeze-drying is a suitable sample preparation technique to study elemental distribution of ions in H. floribundus and P. calomelanos plant tissues using μ-PIXE spectroscopy. Furthermore, cellular structure was preserved in samples prepared using this technique.     

3D Micro-PIXE at atmospheric pressure: A new tool for the investigation of art and archaeological objects

The paper describes a novel experiment characterized by the development of a confocal geometry in an external Micro-PIXE set-up. The position of X-ray optics in front of the X-ray detector and its proper alignment with respect to the proton micro-beam focus provided the possibility of carrying out 3D Micro-PIXE analysis. As a first application, depth intensity profiles of the major elements that compose the patina layer of a quaternary bronze alloy were measured. A simulation approach of the 3D Micro-PIXE data deduced elemental concentration profiles in rather good agreement with corresponding results obtained by electron probe micro-analysis from a cross-sectioned patina sample. With its non-destructive and depth-resolving properties, as well as its feasibility in atmospheric pressure, 3D Micro-PIXE seems especially suited for investigations in the field of cultural heritage.     

Analysis of blood and tissue in gallbladder cancer

Particle induced X-ray emission, particle induced γ-ray emission studies has been carried out to analyse normal and carcinoma tissues and blood samples of gallbladder of both sexes and seventeen trace elements namely Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br and Pb were estimated in the tissue and blood samples. In the present study, concentration of Zn in the carcinoma gallbladder tissue is less than that of the normal gallbladder tissue. Tobacco habit could be one of the important factors to decrease the elemental concentrations in blood and tissue samples.     

Wilson‘s病人和正常人发,粪便中微量元素的中子活化分析

用ＮＡＡ方法测定人发和粪便样品中Ｃｕ、Ｚｎ、Ｃａ、Ｍｎ、Ａｌ和Ｍｇ等六种微量元素，分析比较了病人和正常人样品中微量元素含量的差异。并对病人治疗前后微量元素的变化进行了探讨。     

DISTRIBUTION OF SOME ELEMENTS IN HUMAN HAIR AND ORGANS DETERMINED BY NAA

Twenty four male autopsies were obtained from Shanghai. The samples of liver, lung, kidney cortex, brain and scalp hair were collected from the autopsies. The elements As, Br, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, Mg, Mn, Na, Rb, 8, Se and Zn were determined by neutron activation analysis (NAA). The present study provides the elemental levels of different tissues for normal male adults. The distribution pattern of elements was discussed. Great difference on distribution of some elements in different tissues was observed.     

Biomonitoring study of seasonal anthropogenic influence at the Itamambuca beach (SP, Brazil)

The present work is focused on the study of a seasonal anthropogenic influence on the beach of Itamambuca (Ubatuba, SP, Brazil) carried out using Atherinella brasiliensis as biomonitor. In total 84 fish were caught between July 2004 and February 2005 in different locations at the beach and inside the Itamambuca river. The fish were pooled according to catch and their musculature was analyzed by Particle-Induced X-ray Emission (PIXE) and Rutherford Backscattering (RBS) techniques. While the concentration of light (matrix) elements like C and O were obtained using the RBS technique, major (Na, Mg, P, S, Cl, K and Ca) and trace (Si, Al, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br and Sr) elements were measured by PIXE. The results show that differences were observed for several elemental concentrations of fish tissue between high season (spring-summer) and low season (winter-fall), indicating that increased human activity in the beach during high season may have some impact on the beach ecosystem. The role of the water salinity in the results is also discussed.     

Internal elemental imaging by scanning X-ray fluorescence microtomography at the hard X-ray microprobe beamline of the SSRF: Preliminary experimental results

Synchrotron-based X-ray micro-fluorescence (μ-SXRF) is a non-destructive analytical technique and has been widely used to detect and quantify the elemental composition of samples in their natural state. To determine the internal elemental distributions within samples, X-ray fluorescence microtomography has been developed based on the hard X-ray microprobe at beamline BL15U1 of the Shanghai Synchrotron Radiation Facility (SSRF) in Shanghai, China. This technique was applied to image the cross-sectional distributions of multiple elements within a single human hair, and its validity was evaluated by comparing the results with the elemental maps of a thin hair section obtained using the well-established μ-SXRF mapping method. Elemental images of S, Ca, Mn, Fe, Cu, and Zn within a virtual slice of the hair were reconstructed after the tomographic measurements. The tomographic images of heavy elements like Fe, Cu, and Zn were found to be in good agreement with the corresponding μ-SXRF maps. Light elements, such as S, however, represented different patterns due to non-negligible self-absorption in the sample, and sophisticated correction algorithms accounting for such effects are required for obtaining qualitatively and quantitatively more accurate images. Compared to μ-SXRF mapping, X-ray fluorescence microtomography reduces the sample preparation requirements and has been demonstrated in this work as being a more ideal and effective imaging modality to non-destructively mapping out the internal distribution of heavy elements within samples at the micrometer scale at the SSRF.     

大米中矿质元素含量测定及分析

采用粉末压片制样,用波长色散X射线荧光光谱法对湖北、四川和黑龙江产地大米中Mn、Fe、Cu、Zn、Mg、P、S、K、Ca 9种元素含量进行测定,并用主成分和聚类分析对结果进行分析。讨论了各目标元素测量条件,运用经验系数法和散射射线作内标对基体效应进行校正,通过测量国家生物标准物质建立了工作曲线。分析结果表明,该方法检出限较低、精密度较好、准确度较高,不同产地大米样品中目标元素含量差异显著。前4个主成分的累计方差贡献率为89.3%,30份大米样品分布在三个区域,分别来自三个产地。聚类分析在阈值为9时,将大米样品分成三类,与主成分分析结果一致。因此矿质元素可作为大米产地溯源的指标。     

Soil-to-Plant Transfer Factors of Stable Elements and Naturally Occurring Radionuclides: (2) Rice Collected in Japan

The critical paths of radionuclides and the critical foods in Japan are different from those in European and North American countries because agricultural products and food customs are different. Consequently, safety assessment in Japan is required to consider rice and vegetables as the critical foods. In this study, we measured soil-to-plant transfer factors (TFs) for rice using naturally existing elements as analogues of radionuclides under equilibrium conditions. Rice and associated soil samples were collected from 50 sampling sites throughout Japan and TFs of 36 and 34 elements for brown rice and white rice, respectively, were calculated on dry weight basis.

Probability distributions of TFs of elements for brown rice and white rice were a log normal type. Except for As and Mo, the TFs for brown rice were usually lower than those for wheat and barley especially for K, Fe, Sr (t-test: p < 0:05) and slightly lower than those for Ba, rare earth elements, Th and U. When the TFs of brown rice were compared with those of white rice, TFs of Th and U were higher in white rice, but, for many other elements, the TFs were lower in white rice than those in brown rice. Comparison of the data with previously reported values for Sr and Cs showed that the TFs of stable Sr and Cs were close to the respective values of fallout ⁹⁰Sr and ¹³⁷Cs observed in field experiments. Thus, the TFs of naturally existing elements can be used as TFs of those radionuclides which have been in contact with the environment for a long time and have reached equilibrium conditions.     

Elemental investigation of Syrian medicinal plants using PIXE analysis

Particle induced X-ray emission (PIXE) technique has been employed to perform elemental analysis of K, Ca, Mn, Fe, Cu, Zn, Br and Sr for Syrian medicinal plants used traditionally to enhance the body immunity. Plant samples were prepared in a simple dried base. The results were verified by comparing with those obtained from both IAEA-359 and IAEA–V10 reference materials. Relative standard deviations are mostly within ±5–10% suggest good precision. A correlation between the elemental content in each medicinal plant with its traditional remedial usage has been proposed. Both K and Ca are found to be the major elements in the samples. Fe, Mn and Zn have been detected in good levels in most of these plants clarifying their possible contribution to keep the body immune system in good condition. The contribution of the elements in these plants to the dietary recommended intakes (DRI) has been evaluated. Advantages and limitations of PIXE analytical technique in this investigation have been reviewed.     

In situ analysis of human teeth by external PIXE

The elemental profiles of the enamel, cementum and caries of human teeth were analysed by the external proton induced X-ray emission studies. Ten elements namely P, Ca, V, Mn, Fe, Cu, Zn, As, Sr and Pb were estimated in the present study. P and Ca were found to be the major elements whereas all other elements were found in trace level. It was observed that the respective concentrations of elements namely P, Ca, Fe, Zn and Pb in enamel are more than those in cementum. Concentration of P ranged between 6.37% and 25% whereas Ca ranged between 12.94% and 43.36%.     

PIXE analysis of trace elements in northern fur seal teeth

Trace elements in teeth of northern fur seal Collorhinus ursinus were analyzed by PIXE and micro-PIXE (μ-PIXE). Trace elements such as Mn, Fe, Zn, Cu, As, Br, Sr, and Pb were detected in the teeth, which were composed of hydroxyapatite crystals. Among these elements, the concentrations of Fe and Zn were relatively higher in winter and lower in summer and also Zn varied along with growth of individuals. These elemental fluctuation seems to correspond to the life history of the northern fur seal. It suggests that the PIXE analysis will make a powerful tool to reconstruct the life history.     

Micro-ERDA,micro-RBS and micro-PIXE techniques in the investigation of fish otoliths

Elemental distribution in the otolith of the fresh water fish burbot (Lota lota L.) collected in Hungary was measured with Elastic Recoil Detection Analysis (ERDA), Rutherford Backscattering Spectrometry (RBS) and as a complementary technique, Particle-Induced X-ray Emission (PIXE) with a focussed ion beam of 1.5 × 1.5 μm² spot size. The organic- and inorganic-rich regions of the otolith are distinguished and they are presented as hydrogen and calcium maps at depth regions of 0–70, 70–140 and 140–210 nm. The textured surface of the sample and its porosity were characterized from the effect on the RBS spectra. The oxygen and carbon PIXE elemental maps can also be used to identify the organic- and inorganic-rich regions of the otolith. The calcium map was found to be more homogeneous because the otolith structure is averaged in a larger depth. The trace elements Fe, Zn and Sr were detected only in very low concentration by micro-PIXE.     

Investigation on the stability of water-soluble ZnO quantum dots in KB cells by X-ray fluorescence and absorption methods

The structural stability of water-soluble ZnO quantum dots (QDs) in oral epidermoid carcinoma (KB) cells was studied by the External Micro Proton Induced X-ray Emission (External Micro-PIXE) technique and the X-ray absorption fine structure (XAFS) measurement. The External Micro-PIXE and XAFS experiments were respectively performed at the JAEA and the Shanghai Synchrotron Radiation Facility. The elements’ distributions were detected by the External Micro-PIXE technique. The XAFS method was applied to obtain information about zinc (Zn) K-edge spectra. The fits of the XAFS data showed that the Zn-O bond structure of water-soluble ZnO QDs was stable after being absorbed by KB cells. Its local structural parameters were almost identical with those of the standard wurtzite structure. Water-soluble ZnO QDs had good structural stability in KB cells.     

Role of trace elements in somatic embryogenesis - A PIXE study

Proton induced X-ray emission was used to study the trace elemental profiles of embryogenic and non-embryogenic callus of an important cash crop of India - Plantago ovata. Somatic embryogenesis, a well-known process for plant regeneration and crop improvement is modulated by various factors such as ionizing radiation and micro nutrients in the growth media. The present work reports the trace element variation in normal and irradiated callus tissue of P. ovata. Embryogenic and non-embryogenic callus tissues were exposed to gamma rays from a ⁶⁰Co gamma source. The absorbed dose ranged from 10 to 100 Gy. Subsequent experiments showed significant dose dependent alterations in K, Ca, Mn, Fe, Ni, Cu, Zn, Br, Sr in both the embryogenic and non-embryogenic callus. The precise involvement of these elements has been discussed in light of somatic embryogenesis of the selected medicinal plant.     

糖尿病大鼠组织中微量元素的仪器中子活化分析

使用链脲佐菌素诱导出大鼠的Ｉ型糖尿病（ＩＤＤＭ）模型,以正常大鼠作对照。用仪器中子活化分析法测定了大鼠的肝、肾和胰腺组织中Ａｓ、Ｂｒ、Ｃａ、Ｃｏ、Ｃｌ、Ｃｕ、Ｆｅ、Ｈｇ、Ｍｇ、Ｍｎ、Ｎａ、Ｒｂ、Ｓ、Ｓｅ和Ｚｎ等元素的含量。结果表明,ＩＤＤＭ大鼠模型的这３种组织中的一些微量元素含量发生了明显改变。并对这些元素含量发生变化的原因和意义作了讨论。