Authors:R. Godinho, H. Wolterbeek, M. Pinheiro, L. Alves, T. Verburg, and M. Freitas
The elemental microdistributions of peripheral and central parts of the lichen Flavoparmelia caperata exposed to industrial pollution were analysed, in order to better understand the elements distribution patterns in relation
to the lichen constitution, thereby increasing our knowledge on uptake and release mechanisms. Nuclear microscopy techniques
were used to visualize elemental distributions in sample transepts and associate their concentrations to sample morphology.
The distribution data of the elements studied suggests there is biological regulation of internal concentrations. Considering
thallus parts, element-specific internal translocation should be taken into account as one more factor affecting lichen “memory
The University of Surrey Ion Beam Centre has recently installed a tandem accelerator with a new proton microprobe and the potential for sub-micron beam-spot size. The facilities for Nuclear Microscopy (NM), combining scanning transmission ion microscopy/tomography (STIM-T) and proton induced X-ray emission tomography (PIXE-T) of biological tissues are being developed. This paper will review developments in ion beam tomography of biological samples and methods in accurately producing trace-elemental maps that are meaningful. Cell composition and integrity can be seriously compromized by the preparation of the sample and by beam-induced damage, causing loss of matrix elements as well as a change in cell size. Beam-induced damage, determination of 3-dimensional X-ray attenuation and secondary fluorescence contribute to the complex nature of the reconstruction and interpretation of PIXE-tomographic data. A PIXE, STIM and Rutherford backscatter analysis of leukocytes is presented in part to test the new microprobe but also to identify areas of improvement in facilities at the university and nuclear microscopy in general, in anticipation of producing maps for more direct biological and medical research.
Rapid micron-resolution quantitative elemental mapping is possible at the University of Surrey using a combination of proton
induced X-ray emission tomography (PIXE-T) and simultaneous on/off-axis scanning transmission ion microscopy-tomography (STIM-T).
A preliminary analysis of hair was performed. However, experimental uncertainties lead to large errors in tomograms and this
work focuses on identifying and reducing the sources of error in both tomographic and 2D mapping. The STIM-T counts per pixel
are used to normalise the PIXE-T data for charge. However, the geometry of the collimator and the scattering foil affects
the detection rate since the loss of protons in the collimator increases as energy loss increases due to scattering. Errors
in the PIXE geometric efficiency are greater in mapping when the detector is close to the sample. Moreover when a ‘funny’
filter was used for PIXE-T the uncertainty in the efficiency was found to increase because the sample-filter distance changes
during the experiment.
Authors:D. Beasley, I. Gomez-Morilla, and N. Spyrou
3D quantitative elemental maps of a section of a strand of hair were produced using a combination of PIXE-Tomography and simultaneous
On/Off Axis STIM-Tomography at the University of Surrey Ion Beam Centre. The distributions of S, K, Cl, Ca, Fe and Zn were
determined using the PIXE-T reconstruction package DISRA. The results were compared with conventional bulk PIXE analysis of
tomographic data as determined using Dan32. The overall concentrations determined by PIXE were compared with elemental concentrations
held in the University of Surrey Hair Database. All the entries currently in the database were produced using INAA. The merits
and possible contributions of tomographic PIXE analysis to analysis of hair are discussed. The conclusions drawn from the
PIXE-Tomography analysis can be used to argue for more stringent procedures for hair analysis at the University of Surrey.
The nuclear microprobe enables the localization and the quantitative determination of all elements from hydrogen to uranium using atomic and/or nuclear methods: PIXE, PIGE, RBS, ERDA, NRA, STIM, etc. These methods and the apparatus required are shortly described. Three examples show that complementary information is obtained by nuclear microprobe analysis and NAA. The first example is the study of the abnormal behavior of metallic impurities during the purification of metallurgical grade silicon by directional solidification. This behavior is due to the presence of silicon carbide micro-precipitates at the bottom of the ingots. The second example concerns the determination of trace element (Ni, Mn, Rb, Sr) partition coefficients between a solid phase (mineral) and a liquid phase (lava-glass inclusions). These determinations enable the specification and modelling of the processes which govern the magma evolution in volcanological contexts. The third example deals with the study of trace elements in archeological bones. Using PIXE, PIGE, NRA and NAA, it is possible to correlate the concentrations of some elements, such as C, N, F, and Zn in the femoral diaphyse with both the age, the pathology and diagenetic mechanism of the human being at the moment of death.
Authors:D. Zhu, R. He, W. Yu, C. Li, H. Cheng, B. Zhu, and J. Yan
receptors. SOCC is accomplished by the pore-forming Ca 2+ channel subunits calcium release-activated calcium channel protein (ORAI) 1, ORAI2, and ORAI3 [ 9–11 ] as well as their regulators, stromal interaction molecule (STIM) 1 and STIM2 [ 12 , 13 ]. The
Authors:Gábor Semsey, Gábor Török, Zsófia Csáky-Pallavicini, and Katalin Horváth-Szabó
Die Verfasser haben die
Wirksamkeit der Werteübergabe
in der Gemeinschaft Regnum Marianum untersucht. In ihrer Abhandlung geben sie zunächst einen Überblick über die wichtigsten Aspekte der Werteübergabe, wobei sie sich auf die Kriterien einer erfolgreichen Wertevermittlung konzentrieren, stellen dann kurz die Geschichte der Gemeinschaft Regnum Marianum, ihre gegenwärtige Tätigkeit und die wichtigsten Merkmale ihrer Pädagogik vor. In diesem Zusammenhang erläutern sie auch, wie die Kriterien einer erfolgreichen Werteübergabe in der Regnum-Gemeinschaft erfüllt werden. Als Nächstes stellen sie einige Ergebnisse einer Untersuchung über die Wirksamkeit der Wertevermittlung in der Regnum-Gemeinschaft vor, für die die allgemein gebräuchliche Werteskala nach Rokeach verwendet wurde. Die Ergebnisse werden mit denen einer in ganz Ungarn durchgeführten Untersuchung verglichen, außerdem werden die Unterschiede zwischen den Altersgruppen innerhalb der Gemeinschaft analysiert. Sie kommen zu dem Schluss,
dass die Werteübergabe in der Regnum-Gemeinschaft als relativ erfolgreich bezeichnet werden kann
, wenn man die gesell schaftliche Situation und die ungarische Geschichte der vergangenen Jahrzehnte berücksichtigt.