Dendritic cells (DCs) are the most important antigen-presenting cells able to sense any change in... more Dendritic cells (DCs) are the most important antigen-presenting cells able to sense any change in the environment and to respond by stimulating or suppressing the whole immune system. Such cells are potentially powerful tool for the cell-based anti-tumour therapy. A potential anti-tumour strategy includes the co-delivery of tumour antigens and specific activators into DCs in vivo via gold nanoparticles (GNPs) as carriers. However, many details related to the GNPs’ cytotoxicity, immunomodulatory properties and mechanisms of internalization by DCs remains to be investigated. Using the light microscopy and flow cytometry, we showed that GNPs of different sizes (10nm, 50nm and 90nm) are internalized easily by immature (i)DC, which represent a good target for DC-based vaccines, in contrast to mature (m)DC. State-of-the-art confocal microscopy, focused ion beam/scanning electron microscopy (FIB/SEM) and TEM revealed that GNPs within iDC are distributed predominantly in the endosomal vesic...
ABSTRACT In in-beam {gamma}-ray spectroscopy experiments, we often look for coincident detection ... more ABSTRACT In in-beam {gamma}-ray spectroscopy experiments, we often look for coincident detection events. Among every N events detected, coincidence search is naively of principal complexity O(N{sup 2}). When we limit the approximate width of the coincidence search window, the complexity can be reduced to O(N), permitting the implementation of the algorithm into real-time measurements, carried out indefinitely. We have built an algorithm to find simultaneous events between two detection channels. The algorithm was tested in an experiment where coincidences between X and {gamma} rays detected in two HPGe detectors were observed in the decay of {sup 61}Cu. Functioning of the algorithm was validated by comparing calculated experimental branching ratio for EC decay and theoretical calculation for 3 selected {gamma}-ray energies for {sup 61}Cu decay. Our research opened a question on the validity of the adopted value of total angular momentum of the 656 keV state (J{sup {pi}} = 1/2{sup -}) in {sup 61}Ni.
Assessing the physico-elemental traits of coffee beans may assist in determining its nutritional ... more Assessing the physico-elemental traits of coffee beans may assist in determining its nutritional and commercial value as well as geographical origin. Although a number of studies exist describing the physico-chemical traits of coffee, there are no studies describing the physico-elemental profile of organically produced roasted coffee beans. In this study, the levels of trace and toxic metals in organically produced roasted coffee beans from four top coffee production regions (Ethiopia, Colombia, Honduras, and Mexico) that are commercially available in South Africa were compared using in-air particle induced X-ray emission (PIXE). In addition, physical traits of the roasted coffee beans from the selected regions were compared using microscopy. In-air PIXE analysis revealed the presence of P, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Br, Rb, and Sr in samples. Physical trait data showed that coffee beans from Mexico weighed more than beans from other regions, whilst coffee beans from Honduras had the highest width. In conclusion, physico-elemental analysis using in-air PIXE and microscopy may be promising tools in guiding the nutritional and commercial value as well as geographical origin of coffee.
Page 1. 10th International Conference on Particle Induced X-ray Emission and its Analytical Appli... more Page 1. 10th International Conference on Particle Induced X-ray Emission and its Analytical Applications PIXE 2004, Portoro, Slovenia, June 4-8, 2004 http://pixe2004. ijs.si/ 305.1 Analysis of Slovenian historic materials . mit1 ...
We present the results of our systematic research into moderate temperature diffusion technologie... more We present the results of our systematic research into moderate temperature diffusion technologies of fabrication of optical waveguides in X- and Z-cuts of lithium niobate, i.e. annealed proton exchange (APE) and diffusion doping of erbium from melts containing erbium salts. Our experiments proved, that the X-cuts always contained much more incorporated dopants than the Z-cuts, indicating thus, that the incorporation
Determination of proton charge during in-air PIXE experiments can be hampered when analysing thic... more Determination of proton charge during in-air PIXE experiments can be hampered when analysing thick non-conductive samples. Several arrangements may be used for overcoming this problem, while in studies of historical documents a variant employing X-ray yield measurements on Ar in air is often used. At compact geometry, with a small distance from the exit foil to the sample (10 mm or less), and also with close location of the X-ray detector to the sample to increase the detector solid angle, the uncertainties in the experimental geometry directly influence the accuracy of the PIXE analysis. The factors affecting the accuracy when using Ar yields are estimated. The advantage of the other technique, measuring X-ray radiation from the exit foil, is elaborated.
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, Apr 1, 2002
For fitting PIXE spectra with a computer program the detector response function should be known w... more For fitting PIXE spectra with a computer program the detector response function should be known with good enough precision to guarantee accurate determination of the elemental yields. The response of a semiconductor detector to monochromatic X-ray radiation does not have a simple dependence on energy. Normally, it can be described by a linear combination of several analytical functions: Gaussian or
Elemental concentrations of Sr , Fe , Zn and Cr have been measured by in-air and microbeam PIXE t... more Elemental concentrations of Sr , Fe , Zn and Cr have been measured by in-air and microbeam PIXE to track the changes during the stalagmite growth. The objective was to find the optimal parameters for the measurements of available isotope-dated stalagmite cuts from Slovenian Karst. Significant concentration fluctuations of Fe , Sr and Cr at the scale of several millimetres have been observed by in-air PIXE. Fluctuations of trace elements observed by microbeam PIXE are contributed to the sub annual periods of growth. As demonstrated, a two-dimensional Ca , Sr , Fe and secondary electron mapping is required to avoid regions with mineral inclusions and surface irregularities during line scans over the speleothems. Optimal measuring parameters for microbeam PIXE mapping of large stalagmite cuts already mapped by isotope dating are given. These measurements would account for sub-annual growth fluctuations.
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, Mar 1, 2003
A new type of time detector in annular geometry for time-of-flight (TOF) telescope was designed a... more A new type of time detector in annular geometry for time-of-flight (TOF) telescope was designed and constructed. The start signal is triggered by the secondary electrons emitted from a thin carbon foil placed perpendicularly to the path of the fast ions. The secondary electrons are accelerated through the central hole of the microsphere plate (MSP) by the electric field between
The human neocortex has a cytoarchitecture composed of six layers with an intrinsic organization ... more The human neocortex has a cytoarchitecture composed of six layers with an intrinsic organization that relates to afferent and efferent pathways for a high functional specialization. Various histological, neurochemical, and connectional techniques have been used to study these cortical layers. Here, we explore the additional possibilities of swift ion beam and synchrotron radiation techniques to distinguish cellular layers based on the elemental distributions and areal density pattern in the human neocortex. Temporal cortex samples were obtained from two neurologically normal adult men (postmortem interval: 6-12 h). A cortical area of 500 × 500 μm2 was scanned by a 3 MeV proton beam for elemental composition and areal density measurements using particle induced x-ray emission (PIXE) and scanning transmission ion microscopy (STIM), respectively. Zinc showed higher values in cortical layers II and V, which needs a critical discussion. Furthermore, the areal density decreased in regions with a higher density of pyramidal neurons in layers III and V. Scanning transmission X-ray microscopy (STXM) revealed the cellular density with higher lateral resolution than STIM, but not enough to distinguish each cortical lamination border. Our data describe the practical results of these approaches employing both X-ray and ion-beam based techniques for the human cerebral cortex and its heterogeneous layers. These results add to the potential approaches and knowledge of the human neocortical gray matter in normal tissue to develop improvements and address further studies on pathological conditions.
The application of MeV-SIMS is presented for the detection and mapping of lithium in chemically u... more The application of MeV-SIMS is presented for the detection and mapping of lithium in chemically unprocessed, longitudinally sectioned scalp hair.
Dendritic cells (DCs) are the most important antigen-presenting cells able to sense any change in... more Dendritic cells (DCs) are the most important antigen-presenting cells able to sense any change in the environment and to respond by stimulating or suppressing the whole immune system. Such cells are potentially powerful tool for the cell-based anti-tumour therapy. A potential anti-tumour strategy includes the co-delivery of tumour antigens and specific activators into DCs in vivo via gold nanoparticles (GNPs) as carriers. However, many details related to the GNPs’ cytotoxicity, immunomodulatory properties and mechanisms of internalization by DCs remains to be investigated. Using the light microscopy and flow cytometry, we showed that GNPs of different sizes (10nm, 50nm and 90nm) are internalized easily by immature (i)DC, which represent a good target for DC-based vaccines, in contrast to mature (m)DC. State-of-the-art confocal microscopy, focused ion beam/scanning electron microscopy (FIB/SEM) and TEM revealed that GNPs within iDC are distributed predominantly in the endosomal vesic...
ABSTRACT In in-beam {gamma}-ray spectroscopy experiments, we often look for coincident detection ... more ABSTRACT In in-beam {gamma}-ray spectroscopy experiments, we often look for coincident detection events. Among every N events detected, coincidence search is naively of principal complexity O(N{sup 2}). When we limit the approximate width of the coincidence search window, the complexity can be reduced to O(N), permitting the implementation of the algorithm into real-time measurements, carried out indefinitely. We have built an algorithm to find simultaneous events between two detection channels. The algorithm was tested in an experiment where coincidences between X and {gamma} rays detected in two HPGe detectors were observed in the decay of {sup 61}Cu. Functioning of the algorithm was validated by comparing calculated experimental branching ratio for EC decay and theoretical calculation for 3 selected {gamma}-ray energies for {sup 61}Cu decay. Our research opened a question on the validity of the adopted value of total angular momentum of the 656 keV state (J{sup {pi}} = 1/2{sup -}) in {sup 61}Ni.
Assessing the physico-elemental traits of coffee beans may assist in determining its nutritional ... more Assessing the physico-elemental traits of coffee beans may assist in determining its nutritional and commercial value as well as geographical origin. Although a number of studies exist describing the physico-chemical traits of coffee, there are no studies describing the physico-elemental profile of organically produced roasted coffee beans. In this study, the levels of trace and toxic metals in organically produced roasted coffee beans from four top coffee production regions (Ethiopia, Colombia, Honduras, and Mexico) that are commercially available in South Africa were compared using in-air particle induced X-ray emission (PIXE). In addition, physical traits of the roasted coffee beans from the selected regions were compared using microscopy. In-air PIXE analysis revealed the presence of P, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Br, Rb, and Sr in samples. Physical trait data showed that coffee beans from Mexico weighed more than beans from other regions, whilst coffee beans from Honduras had the highest width. In conclusion, physico-elemental analysis using in-air PIXE and microscopy may be promising tools in guiding the nutritional and commercial value as well as geographical origin of coffee.
Page 1. 10th International Conference on Particle Induced X-ray Emission and its Analytical Appli... more Page 1. 10th International Conference on Particle Induced X-ray Emission and its Analytical Applications PIXE 2004, Portoro, Slovenia, June 4-8, 2004 http://pixe2004. ijs.si/ 305.1 Analysis of Slovenian historic materials . mit1 ...
We present the results of our systematic research into moderate temperature diffusion technologie... more We present the results of our systematic research into moderate temperature diffusion technologies of fabrication of optical waveguides in X- and Z-cuts of lithium niobate, i.e. annealed proton exchange (APE) and diffusion doping of erbium from melts containing erbium salts. Our experiments proved, that the X-cuts always contained much more incorporated dopants than the Z-cuts, indicating thus, that the incorporation
Determination of proton charge during in-air PIXE experiments can be hampered when analysing thic... more Determination of proton charge during in-air PIXE experiments can be hampered when analysing thick non-conductive samples. Several arrangements may be used for overcoming this problem, while in studies of historical documents a variant employing X-ray yield measurements on Ar in air is often used. At compact geometry, with a small distance from the exit foil to the sample (10 mm or less), and also with close location of the X-ray detector to the sample to increase the detector solid angle, the uncertainties in the experimental geometry directly influence the accuracy of the PIXE analysis. The factors affecting the accuracy when using Ar yields are estimated. The advantage of the other technique, measuring X-ray radiation from the exit foil, is elaborated.
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, Apr 1, 2002
For fitting PIXE spectra with a computer program the detector response function should be known w... more For fitting PIXE spectra with a computer program the detector response function should be known with good enough precision to guarantee accurate determination of the elemental yields. The response of a semiconductor detector to monochromatic X-ray radiation does not have a simple dependence on energy. Normally, it can be described by a linear combination of several analytical functions: Gaussian or
Elemental concentrations of Sr , Fe , Zn and Cr have been measured by in-air and microbeam PIXE t... more Elemental concentrations of Sr , Fe , Zn and Cr have been measured by in-air and microbeam PIXE to track the changes during the stalagmite growth. The objective was to find the optimal parameters for the measurements of available isotope-dated stalagmite cuts from Slovenian Karst. Significant concentration fluctuations of Fe , Sr and Cr at the scale of several millimetres have been observed by in-air PIXE. Fluctuations of trace elements observed by microbeam PIXE are contributed to the sub annual periods of growth. As demonstrated, a two-dimensional Ca , Sr , Fe and secondary electron mapping is required to avoid regions with mineral inclusions and surface irregularities during line scans over the speleothems. Optimal measuring parameters for microbeam PIXE mapping of large stalagmite cuts already mapped by isotope dating are given. These measurements would account for sub-annual growth fluctuations.
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, Mar 1, 2003
A new type of time detector in annular geometry for time-of-flight (TOF) telescope was designed a... more A new type of time detector in annular geometry for time-of-flight (TOF) telescope was designed and constructed. The start signal is triggered by the secondary electrons emitted from a thin carbon foil placed perpendicularly to the path of the fast ions. The secondary electrons are accelerated through the central hole of the microsphere plate (MSP) by the electric field between
The human neocortex has a cytoarchitecture composed of six layers with an intrinsic organization ... more The human neocortex has a cytoarchitecture composed of six layers with an intrinsic organization that relates to afferent and efferent pathways for a high functional specialization. Various histological, neurochemical, and connectional techniques have been used to study these cortical layers. Here, we explore the additional possibilities of swift ion beam and synchrotron radiation techniques to distinguish cellular layers based on the elemental distributions and areal density pattern in the human neocortex. Temporal cortex samples were obtained from two neurologically normal adult men (postmortem interval: 6-12 h). A cortical area of 500 × 500 μm2 was scanned by a 3 MeV proton beam for elemental composition and areal density measurements using particle induced x-ray emission (PIXE) and scanning transmission ion microscopy (STIM), respectively. Zinc showed higher values in cortical layers II and V, which needs a critical discussion. Furthermore, the areal density decreased in regions with a higher density of pyramidal neurons in layers III and V. Scanning transmission X-ray microscopy (STXM) revealed the cellular density with higher lateral resolution than STIM, but not enough to distinguish each cortical lamination border. Our data describe the practical results of these approaches employing both X-ray and ion-beam based techniques for the human cerebral cortex and its heterogeneous layers. These results add to the potential approaches and knowledge of the human neocortical gray matter in normal tissue to develop improvements and address further studies on pathological conditions.
The application of MeV-SIMS is presented for the detection and mapping of lithium in chemically u... more The application of MeV-SIMS is presented for the detection and mapping of lithium in chemically unprocessed, longitudinally sectioned scalp hair.
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