| 1. |
- Gram, Magnus, et al.
(författare)
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Bystander cell death and stress response is inhibited by the radical scavenger α(1)-microglobulin in irradiated cell cultures.
- 2010
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Ingår i: Radiation Research. - 0033-7587. ; 174:5, s. 590-600
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Tidskriftsartikel (refereegranskat)abstract
- Alpha-particle irradiation of cells damages not only the irradiated cells but also nontargeted bystander cells. It has been proposed that the bystander effect is caused by oxidants and free radicals generated by the radiation. Recent studies have shown that α(1)-microglobulin protects against cell damage caused by oxidants and free radicals. Using a novel experimental system that allows irradiation of 0.02% of a human hepatoma monolayer, leaving 99.98% as bystander cells, we investigated the influence of oxidative stress and the cell-protective effects of α(1)-microglobulin during α-particle irradiation. The results showed an increase in cell death in both irradiated cells and bystander cells. A significant increase in apoptosis, oxidation markers and expression of the stress response genes heme oxygenase 1, superoxide dismutase, catalase, glutathione peroxidase 1, p21 and p53 were observed. Addition of α(1)-microglobulin reduced the amount of dead cells and inhibited apoptosis, formation of oxidation markers, and up-regulation of stress response genes. The results emphasize the role of oxidative stress in promoting bystander effects. Furthermore, the results suggest that α(1)-microglobulin protects nonirradiated cells by eliminating oxidants and free radicals generated by radiation and imply that α(1)-microglobulin can be used in radiation therapy of tumors to minimize damage to surrounding tissues.
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| 2. |
- Abdel, Naseem, et al.
(författare)
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Fabrication and Characterization of Ultra-Thin PIN Silicon Detectors for Counting the Passage of MeV Ions
- 2013
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499. ; 60:2, s. 1182-1188
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the fabrication and initial characterization of an ultra-thin silicon PIN detector using a new technique in silicon nanotechnology. In collaboration with the Nuclear Physics Division and the Lund Nano Lab at Lund University, we have developed and manufactured ultra thin Delta E-detectors for spectroscopic applications. The fabrication process has been carried out using a double-polished silicon substrate n-type wafer and locally thinning by means of a 10:1 solution of 25% tetramethyl ammonium hydroxide (TMAH) with Isopropyl alcohol. More than 100 detectors of different thicknesses, down to 5 mu m with active areas ranging from 0.71 to 0.172 mm(2), have been fabricated. The main design considerations of our thin detectors were a very low leakage current below 12 nA and a low full depletion voltage at a reverse bias less than 1.5 V. Finally, most of our thin detectors offer an energy resolution (FWHM) as low as 31 keV for 5.487 MeV alpha particles from a Am-241 source.
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| 3. |
- Abdel, Naseem S., et al.
(författare)
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Characterizations of new Delta E detectors for single-ion hit facility
- 2014
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 318, s. 281-286
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the performance evaluation of new Delta E detectors to be used as pre-cell hit detectors in living cell irradiation experiments at the Lund Ion Beam Analysis facility (LIBAF). Using these detectors with a thickness down to 4.15 mu m fabricated at Lund University, an experiment was setup in which Delta E-detectors were used together with a stop E-detector in a telescope system under coincidence measurements. The characteristics of Delta E detectors were based on the optimal detection of the passage of 2.55 MeV protons. The results of these tests demonstrate that the detector telescope clearly separates the protons, this due to high signal-to-noise ratio and good energy resolution of the Delta E-detectors. The best performing detector was shown to have a detection efficiency of 95% at thickness of 9.7 mu m. This type of high-performing detector is suitable for the planned role of the Delta E-detector in the future cell irradiation experiments. (C) 2013 Elsevier B.V. All rights reserved.
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| 4. |
- Abdel, N. S., et al.
(författare)
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Efficient ultra-thin transmission silicon detectors for a single-ion irradiation system at the Lund Ion Beam Analysis Facility
- 2014
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the fabrication of efficient ultra-thin silicon transmission detectors for use as pre-cell detectors in single-ion experiments on living cells at the Lund Ion Beam Analysis Facility. More than 40 detectors of different thicknesses down to 5 mu m have been fabricated and packaged. The main design considerations were very low leakage current (below 9 nA) and low full depletion voltage at biases less than 0.5 V at room temperature. In addition, we have shown that cooling the device can reduce the leakage current to 3 nA. The experimental testing of the pre-cell detection system is based on counting the passage of ions through the transmission (Delta E) detector before hitting the stopping (E) detector placed behind it, to ensure the accurate delivery of specific doses of radiation to the sample. Optimal detection of the fabricated detectors for the passage of an external beam of 2.2 MeV protons was obtained by cooling the device to below 2 degrees C. Cooling the Delta E detectors provides up to 20% better energy resolution and up to 98% detection efficiency for 2.2 MeV protons. The development of this kind of efficient pre-cell detector enables a range of new experiments to be conducted on thick biological samples.
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| 5. |
- Abdel, Naseem S., et al.
(författare)
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Modification of spray-deposited CdO thin films by 1.5 MeV proton irradiation
- 2022
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 511, s. 57-63
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Tidskriftsartikel (refereegranskat)abstract
- Thin films of cadmium oxide (CdO) with different thicknesses in the range of 78–250 nm were prepared and deposited on glass substrates by using a spray pyrolysis technique. A microbeam facility (Lund Ion Beam Analysis facility) was used to irradiate the prepared CdO thin films with a 1.5 MeV proton beam for fluence in the range of 2 × 1012–2 × 1014 ions/cm2. The surface morphology of the CdO films was measured by atomic force microscopy, and it was observed that the grain size and surface roughness were increased as a function of ion fluence. A UV spectrophotometer was used to study the optical properties of the samples, and the results revealed that the absorbance and optical band gaps increased with an increase in the proton fluence and CdO film's thickness. This work explores the possibility of CdO material modification using low-energy proton irradiation.
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| 6. |
- Aguer, P, et al.
(författare)
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Skin morphology and layer identification using different STIM geometries
- 2005
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 231:1-4, s. 292-299
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Tidskriftsartikel (refereegranskat)abstract
- The use of on-axis geometry in scanning transmission ion microscopy (STIM) has been widely used for thin biological sample structure identification. In this configuration, the lateral resolution is optimised so that micron or submicron beam spots are easily achieved even for classic microbeam lines. Off-axis STIM was more particularly employed for rapid imaging, and also (when associated to a scattering set-up) for normalising elemental contents obtained by other ion beam analysis techniques in organic thin samples. Due to the very small beam current required, on-axis STIM is a stand-alone technique. Off-axis STIM can be advantageous as it enables the simultaneous utilisation of PIXE and RBS techniques. In this paper, the STIM images obtained with an on-axis geometry, a standard off-axis geometry and a recently developed on-off geometry are presented and discussed. Data from skin samples are used for comparison purposes aiming at studying skin permeability to sunscreens. Skin is a stratified tissue and the precise identification of skin layers is needed to ascertain the penetration depth of the physical filter from the formulation. In addition to the intrinsic difference in image quality due to the beam resolution, the influence of the detector type, implanted silicon detector versus Si pin diode, is discussed on the basis of their energy resolution.. their resistance to beam damage as well as the effect
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| 7. |
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| 8. |
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| 9. |
- Arteaga, Natalia, et al.
(författare)
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A SU-8 dish for cell irradiation
- 2007
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 263:2, s. 523-528
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Tidskriftsartikel (refereegranskat)abstract
- The objective of the CELLION project is radiation research at low doses. The main cell responses to low dose irradiation are bystander effects, genomic instability and adaptive responses. In order to study these effects it is convenient to make the cells addressable in space and time through locking the cell position. A new alternative dish has been developed for irradiation procedures at the Lund Nuclear Probe. The versatile dish can be used both to cultivate and to hold the cells during the irradiation procedure. The irradiation dish is made of an epoxy-based photopolymer named SU-8 chosen by its flexibility, non-toxicity and biological compatibility to cell attachment. It has been fabricated using a UV lithographic technique. The irradiation dish forms a 2 × 2 mm2 grid which contains 400 squares. Each square has 80 μm side and is separated from neighbouring ones by 20 μm wide walls. The location of each square is marked by a row letter and column number patterned outside the grid. The Cell Irradiation Facility at the Lund Nuclear Probe utilizes protons to irradiate living cells. A post-cell detection set up is used to control the applied dose, detecting the number of protons after passing through the targeted cell. The transmission requirement is fulfilled by our new irradiation dish. So far, the dish has been used to perform non-targeted irradiation of Hepatoma cells. The cells attach and grow easily on the SU-8 surface. In addition, the irradiation procedure can be performed routinely and faster since the cells are incubated and irradiated in the same surface.
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| 10. |
- Arteaga, Natalia, et al.
(författare)
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Applications of SU-8 in the development of a Single Ion Hit Facility
- 2009
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 267:12-13, s. 2117-2121
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Konferensbidrag (refereegranskat)abstract
- The Lund Nuclear Microprobe (LNM) has been adapted to be used as a Single Ion Hit Facility (SIHF) for proton cell irradiation experiments at low dose. In order to test the capabilities of the system, Ni dot arrays and artificial cells have been fabricated with the photopolymer SU-8 and common lithographic techniques. The primary purpose of the Ni dot arrays was to determine the targeting accuracy of the beam in vacuum and in air. Additionally, this sample was employed to evaluate the system performance during cell target irradiation experiments. The Ni dot arrays were also used for beam characterization. The artificial cells were originally fabricated to test the software for cell recognition and localization, developed and implemented at the LNM. However, this sample became very functional to make small adjustments at the irradiation chamber for cell irradiation experiments. A description of the samples, fabrication procedure and applications are presented in this paper. (C) 2009 Elsevier B.V. All rights reserved.
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