Hiroyuki Iso

RUBIDIUM DISTRIBUTION IN KIDNEYS OF IMMATURE RATS

Synchrotron radiation X-ray fluorescence (SR-XRF) using high energy incident X-rays was combined with micro-PIXE to analyze the renal distribution of Rb and essential elements in immature rats. The Rb concentrations in the kidneys of newborn (1 week old) and young (3 weeks old) rats were 4.19 ± 0.71 and 4.13 ± 0.30 µg/g, respectively, similar to those of adult rats. Rubidium as well as Zn was detected more in the cortex than the medulla, while Fe was concentrated in the outermost areas of the medulla of newborn rats. The renal structures of young rats achieved adult zonation into the cortex, the outer medulla and the inner medulla. Rubidium was high in the outer stripe of the outer medulla. Further analysis at higher resolution revealed Rb in the proximal tubules in the innermost part of the cortex. These results indicated that Rb was distributed downstream of the proximal tubules. This profile was similar to that of potassium, an Rb congener.

APPLICATION OF MICRO-PIXE ANALYSIS FOR A MIGRATION HISTORY STUDY OF HUCHO PERRYI FOCUSED ON STRONTIUM DISTRIBUTION IN FISH SCALES

Sakhalin taimen, Hucho perryi, is one of the largest freshwater fish in Japan, where it is close to extinction because of indiscriminate fishing, water pollution, and river construction. Interpretable ecological information about the species, however, is scarce. We examined the migration history of H. perryi by analysis of strontium (Sr) content in fish scales using inductively coupled plasma mass spectrometry and Sr distributions associated with ridges (growth lines) in the scales, with micro-beam scanning PIXE (micro-PIXE) analyses. Sr levels in the scales of H. perryi collected along the Sarufutsu coast were higher than those of salmonid collected at Shumarinai, a freshwater lake. Micro-PIXE line analyses showed that the scale Sr values of the Shumarinai Lake samples remained consistently low from the edge toward the core of the scales. The Sr values from the Sarufutsu coast samples remained relatively high from the edge toward the core; Sr levels from second to fourth position from the edge were about ten times higher than the mean levels of Shumarinai Lake samples. These results suggested that H. perryi from the Sarufutsu Coast had experienced the marine environment.

DEVELOPMENT OF DROPLET-PIXE SYSTEM FOR ENVIRONMENTAL MONITORING SAMPLES

PIXE is a trace analytical method. During the sample preparation process for PIXE analysis, there may be loss of element due to sublimation or evaporation that must be considered for quantitative analysis. To avoid such problems, suitable droplet PIXE system has been developed for determination of elemental abundances of liquid samples in atmospheric condition. The system has several dripping modes in order to enhance advantage of dripping method over static liquid target method. The droplet-PIXE system has been applied to a few case studies. Its advantages over other PIXE system will be discussed in this paper.

DIAGNOSIS OF SPATIAL RESOLUTION FOR MICROBEAM SCANNING PIXE USING STIM METHOD AND CR-39 TRACK DETECTOR IN PASTA

In PIXE analysis system and Tandem Accelerator facility (PASTA) of NIRS, we are using Scanning Transmission Ion Microscopy (STIM) method and solid track detector to diagnose the spatial resolution of scanning microbeam PIXE analysis system. These methods are widely used by many microbeam facilities.

EVALUATION OF PRESSED POWDERS AND THIN SECTION STANDARDS FOR MULTI-ELEMENTAL ANALYSIS BY CONVENTIONAL AND MICRO-PIXE ANALYSIS

For muti-elemental analysis, various standards are used to quantify the elements consists of environmental and biological samples. In this paper two different configuration standards, pressed powders and thin section standards, were assessed for their purpose as standards by conventional and micro-PIXE analysis. Homogeneity of manganese, iron, zinc (Zn), copper and yttrium added to pressed powder standard materials were validated and the relative standard deviation (RSD) of the X-ray intensity of the standards was <10% within the range, 62.5–250 µg/g. We established linear relationships between the metal concentration and the specific X-ray intensity of standards containing up to 250 µg/g of these metals. A homogenous distribution of Zn added to thin section standard materials was also confirmed by 10-µm-step scanning of the standard within the range, 50–250 µg/g (RSD ~ 10%). The calibration line between the X-ray intensity obtained from a 10-µm2 area and the metal concentration was acceptable.

ELEMENTAL IMAGING IN PANCREAS OF IMMATURE RATS BY MICRO PIXE ANALYSIS

The pancreas is a large gland capable of both exocrine and endocrine functions; it releases digestive enzymes into the duodenum and hormones into the bloodstream. It is known that Zn plays a key role in the synthesis and action of insulin, one of the pancreatic hormones. However, elemental profiles of the pancreas are not well understood. Here, we examined precise distributions of elements in the pancreas of newborn and young rats by scanning microbeam particle induced X-ray emission (micro PIXE) analysis and compared the results to those of adult animals. Micro PIXE analysis revealed a site-specific distribution of elements in the two major compartments of the pancreas, the exocrine (acinar tissue) and the endocrine portions (islets of Langerhans). The Zn concentrations in the pancreas of the newborn (six days), young (three weeks), and adult rats (ten weeks) were 11.3 ± 2.5 μg/g wet weight, 7.26 ± 0.36 μg/g wet weight, and 10.8 ± 1.1 μg/g wet weight, respectively. In newborn and young rats, Zn was detected mainly in the islets of Langerhans, while K and P were distributed more to the acinar tissues than the islet cells. The site-specific distributions of K, P, and Zn were more obvious in the adult animals.

EVALUATION OF THIN SECTION STANDARDS FOR LOCAL ANALYSIS OF LIGHT ELEMENTS BY MICRO-PIXE ANALYSIS

For quantitative measurements of light elements by micro-PIXE (particle-induced X-ray emission) analysis, suitable external standards have been expected. In this paper thin sections of polyvinyl alcohol solution containing phosphorus (P) and potassium (K) were assessed for their purpose as standards by micro-PIXE analysis. Homogeneity of P and K added to the standard materials were validated by 1 μm and 10 μm-step scanning of the standard. The relative standard deviations of the X-ray intensity of the standards P and K were < 25% and <16%, respectively. The calibration line between the X-ray intensity obtained from a 100 × 100 μm2 area and the elements concentration was also acceptable, indicating that the thin section standards are adequate for an external standard of micro-PIXE measurements for light elements.

PIXE ANALYSIS ON PREDOMINANT ELEMENTAL ACCUMULATION ON THE MANDIBLE OF VARIOUS TERMITES

Information concerning the metallic component of termite mandibles may provide a significant clue for solving the evolutionary theory of termite species. Micro-beam scanning PIXE analysis was used, which is a power tool for detecting elemental components, along with two-dimensional information about the elemental distribution in the analyzed area. The distribution of three specific elements (Mn, Zn and Cl) is the focus of this paper. Especially, Mn and Zn are known to be distinctive factors in taxonomic studies of termite mandibles. In this study, mandibles of 12 species from 5 families were analyzed. Mn was detected in all the termites, except for Mastotermes darwiniensis. On the other hand, only kalotermitid termites had Zn as a predominant metal in the cutting edges. The elemental analysis of these mandibles showed significant information to solve the uncertainty of the phylogenetic relation of termites.

LOCAL ANALYSIS OF STRONTIUM USING FISH SCALE BY MICRO-PIXE WITH A CdTe X-RAY DETECTOR

Sr is an indicator used in studies on fish migration. In this study, the Sr profiles of ridges, which are growth lines in fish scales, in Sakhalin taimen (Hucho perryi) were examined by micro-PIXE analysis. Sakhalin taimen were reared under freshwater conditions for six months. The ridges that formed during the rearing experiment were subjected to PIXE spot analysis. This analysis was performed in a 5 X 5 μm2 area in the center region of each ridge of the scale section, and the Sr levels were calculated using the thin-section standard. The mean Sr concentration in the ridges was 428± 48 μg/g. The quantitative PIXE spot analysis successfully provided Sr profiles for the scale corresponding to ridge formation.

ELEMENTAL ANALYSIS OF ATMOSPHERIC PARTICLES COLLECTED ON POLYTETRAFLUOROETYLENE (PTFE) FILTER USING IN-AIR HELIUM ION INDUCED X-RAY EMISSION METHOD

In order to confirm the availability of an in-air Helium ion induced X-ray emission method for multi-elemental analysis of polytetrafluoroetylene (PTFE) filter sample containing atmospheric particles, NIST urban particulate matter (SRM 1648) collected on PTFE filter using a special small chamber was analyzed by an in-air PIXE method with Helium ions and a proton beam. In addition, we analyzed 10 elements, mixing a standard solution with different concentrations to confirm detection sensitivity of characteristic X-ray peaks. As a result, it is suggested that 1) elements that are lighter than Zn and Pb can be satisfactorily measured using the in-air Helium ion induced X-ray emission method if the amount contained in the filter sample is at least 0.1 mg/L, i.e., 15 ng/cm2, 2) the in-air Helium ion induced X-ray emission method is useful as a method for quantitatively analyzing the light elements such as Mg, Al, Si, S and Cl that are important for identifying the behavior and characteristics of atmospheric particles from the PTFE filter sample containing atmospheric particles, and 3) in the case of the PTFE filter sample containing atmospheric particles, it is possible to measure elements from Mg to Pb by means of analysis using Helium ions and protons.