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  • 1.
    Aldahan, Ala Adin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Morad, Sadoon
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Sturesson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    ElSaiy, A.
    10Be in rhodochrosite nodules from Neogene sediments along the Galapagos Ridge, equatorial Pacific2010In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 268, no 7-8, p. 1253-1256Article in journal (Refereed)
    Abstract [en]

    Microcrystalline, calcian rhodochrosite occurs as nodules around burrows in late Neogene pelagic sediments from the Galapagos Ridge in the Guatemala Basin, eastern equatorial Pacific (DSDP Leg 68; Site 503). Be-10 isotope revealed that the rhodochrosite nodules have formed under growth conditions much faster than those reported for Fe-Mn nodules. The overall REE patterns of the nodules and host pelagic sediments indicate element derivation mainly from marine pore water. However, variations in the shale normalised Eu values suggest influx of hydrothermal fluids into mounds area at Galapagos, which is also evidenced by the similar minor and major element contents in the nodules and host sediments.

  • 2.
    Aldahan, Ala
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Scherer, Reed
    Sjunneskog, C
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Berggren, A-M
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Cosmogenic 10Be as an environmental tracer in subglacial Antarctic Lake2006In: SALE advanced Science and Technology Workshop, 24-26 April, Grenoble, France,, 2006, p. 2-3Conference paper (Refereed)
  • 3.
    Audren, Auregane
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Linnarsson, M. K.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Damage recovery in ZnO by post-implantation annealing2010In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 268, no 11-12, p. 1842-1846Article in journal (Refereed)
    Abstract [en]

    ZnO bulk samples were implanted with 200 key-Co ions at room temperature with two fluences, 1 x 10(16) and 8 x 10(16) cm(-2), and then annealed in air for 30 min at different temperatures up to 900 degrees C. After the implantation and each annealing step, the samples were analyzed by Rutherford backscattering spectrometry (RBS) in random and channeling directions to follow the evolution of the disorder profile. The RBS spectra reveal that disorder is created during implantation in proportion to the Co fluence. The thermal treatments induce a disorder recovery, which is however, not complete after annealing at 900 degrees C, where about 15% of the damage remains. To study the Co profile evolution during annealing, the samples were, in addition to RBS, characterized by secondary ion mass spectrometry (SIMS). The results show that Co diffusion starts at 800 degrees C, but also that a very different behavior is seen for Co concentrations below and above the solubility limit.

  • 4.
    Berggren, Ann-Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    10Be in ice - four decades, two ice sheets, 15 deep coring sites2010Conference paper (Other academic)
  • 5.
    Berggren, Ann-Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Haltia-Hovi, Eeva
    Saarinen, Timo
    Six centuries of annually resolved 10Be in varved lake sediments and its relation to production rates2010Conference paper (Other academic)
  • 6.
    Berggren, Ann-Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Haltia-Hovi, Eeva
    University of Turku, Finland.
    Saarinen, Timo
    University of Turku, Finland.
    Solar cycle variations reflected in 10Be in varved lake sediments, 1900-2006 AD2009Manuscript (preprint) (Other academic)
  • 7.
    Berggren, Ann-Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Sturevik Storm, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Surface and snow pit 10Be from the NEEM drill site, Greenland2010Conference paper (Other academic)
  • 8.
    Berggren, Ann-Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Beer, Juerg
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Kubik, Peter
    ETH, Zurich, Switzerland.
    Christl, Marcus
    ETH, Zurich, Switzerland.
    Johnsen, Sigfús J.
    Niels Bohr Institute, Copenhagen, Denmark.
    Abreu, José
    Eawag, Zurich, Switzerland.
    Vinter, Bo M.
    Niels Bohr Institute, Copenhagen, Denmark.
    A 600-year annual 10Be record from the NGRIP ice core, Greenland2009In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 36, p. L11801-Article in journal (Refereed)
    Abstract [en]

    Despite the extensive use of 10Be as the most significant information source on past solar activity, there has been only one record (Dye-3, Greenland) providing annual resolution over several centuries. Here we report a new annual resolution 10Be record spanning the period 1389-1994 AD, measured in an ice core from the NGRIP site in Greenland. NGRIP and Dye-3 10Be exhibits similar long-term variability, although occasional short term differences between the two sites indicate that at least two high resolution 10Be records are needed to assess local variations and to confidently reconstruct past solar activity. A comparison with sunspot and neutron records confirms that ice core 10Be reflects solar Schwabe cycle variations, and continued 10Be variability suggests cyclic solar activity throughout the Maunder and Spörer grand solar activity minima. Recent 10Be values are low; however, they do not indicate unusually high recent solar activity compared to the last 600 years.

  • 9.
    Palmblad, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Ramström, Margareta
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Bailey, Christopher G
    Chemistry and Materials Science, Lawrence Livermore National Laboratory, USA.
    McCutchen-Maloney, Sandra L
    Biology and Biotechnology Research Program, Lawrence Livermore National Laboratory, USA.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Zeller, Loreen C
    Chemistry and Materials Science, Lawrence Livermore National Laboratory, Livermore, CA 94551-0808, USA.
    Protein identification by liquid chromatography-mass spectrometry using retention time prediction2004In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 803, no 1, p. 131-135Article in journal (Refereed)
    Abstract [en]

    Liquid chromatography has been coupled with mass spectrometry to improve the dynamic range and to reduce the complexity of sample introduced to the mass spectrometer at any given time. The chromatographic separation also provides information on the analytes, such as peptides in enzymatic digests of proteins; information that can be used when identifying the proteins by peptide mass fingerprinting. This paper discusses a recently introduced method based on retention time prediction to extract information from chromatographic separations and the applications of this method to protein identification in organisms with small and large genomes.

  • 10.
    Petersson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Ion Beam Analysis of First Wall Materials Exposed to Plasma in Fusion Devices2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    One major step needed for fusion to become a reliable energy source is the development of materials for the extreme conditions (high temperature, radioactivity and erosion) caused by hot plasmas. The main goal of the present study is to use and optimise ion beam methods (lateral resolution and sensitivity) to characterise the distribution of hydrogen isotopes that act as fuel. Materials from the test reactors JET (Joint European Torus), TEXTOR (Tokamak Experiment for Technology Oriented Research) and Tore Supra have been investigated.

    Deuterium, beryllium and carbon were measured by elastic recoil detection analysis (ERDA) and nuclear reaction analysis (NRA). To ensure high 3D spatial resolution a nuclear microbeam (spot size <10 µm) was used with 3He and 28Si beams. The release of hydrogen caused by the primary ion beam was monitored and accounted for.

    Large variations in surface (top 10 µm) deuterium concentrations in carbon fibre composites (CFC) from Tore Supra and TEXTOR was found, pointing out the importance of small pits and local fibre structure in understanding fuel retention. At deeper depths into the CFC limiter tiles from Tore Supra, deuterium rich bands were observed confirming the correlation between the internal material structure and fuel storage in the bulk.

    Sample cross sections from thick deposits on the JET divertor showed elemental distributions that were dominantly laminar although more complex structures also were observed. Depth profiles of this kind elucidate the plasma-wall interaction and material erosion/deposition processes in the reactor vessel.

    The information gained in this thesis will improve the knowledge of first wall material for the next generation fusion reactors, concerning the fuel retention and the lifetime of the plasma facing materials which is important for safety as well as economical reasons.

    List of papers
    1. Measurement of hydrogen isotopes by nuclear microprobe
    Open this publication in new window or tab >>Measurement of hydrogen isotopes by nuclear microprobe
    2008 (English)In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 100, no 6, p. 062029-Article in journal (Refereed) Published
    National Category
    Subatomic Physics Engineering and Technology
    Research subject
    Ion Physics
    Identifiers
    urn:nbn:se:uu:diva-111090 (URN)10.1088/1742-6596/100/6/062029 (DOI)000275655200225 ()
    Available from: 2009-12-03 Created: 2009-12-03 Last updated: 2018-12-10Bibliographically approved
    2. Mapping of hydrogen isotopes with a scanning nuclear microprobe
    Open this publication in new window or tab >>Mapping of hydrogen isotopes with a scanning nuclear microprobe
    Show others...
    2008 (English)In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 266, no 10, p. 2429-2432Article in journal (Refereed) Published
    Abstract [en]

    Elastic recoil detection analysis using heavy ions with a scanning nuclear microprobe was applied to determine the content of hydrogen isotopes in carbon material facing fusion plasma in the JET fusion reactor. The hydrogen and deuterium concentrations in re-deposited material were obtained by mapping a cross sectional cut of a wall sample. De-trapping and hydrogen release caused by the primary ion beam were investigated. For both the deuterium and hydrogen concentration a drop of similar to 75% was observed from an extrapolated initial value to a final steady state region. A procedure was used to determine the initial concentration. In this way a mapping of the initial deuterium concentration could be obtained.

    National Category
    Physical Sciences Subatomic Physics Engineering and Technology
    Research subject
    Ion Physics
    Identifiers
    urn:nbn:se:uu:diva-111087 (URN)10.1016/j.nimb.2008.03.059 (DOI)000257185600075 ()
    Available from: 2009-12-03 Created: 2009-12-03 Last updated: 2018-12-10Bibliographically approved
    3. Ion beam micro analysis of deposits at tokamak divertor surfaces
    Open this publication in new window or tab >>Ion beam micro analysis of deposits at tokamak divertor surfaces
    Show others...
    2010 (English)In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 268, no 11-12, p. 1838-1841Article in journal (Refereed) Published
    Place, publisher, year, edition, pages
    Amsterdam: Elsevier, 2010
    Keywords
    Nuclear reaction analysis; Micro-beam; Deuterium; Beryllium
    National Category
    Other Engineering and Technologies not elsewhere specified
    Identifiers
    urn:nbn:se:uu:diva-128871 (URN)10.1016/j.nimb.2010.02.025 (DOI)000278702300032 ()
    Available from: 2010-07-29 Created: 2010-07-29 Last updated: 2017-12-12Bibliographically approved
    4. Nuclear reaction analysis with ion microbeam of cross sections of surface layers deposited in tokamak divertor
    Open this publication in new window or tab >>Nuclear reaction analysis with ion microbeam of cross sections of surface layers deposited in tokamak divertor
    Show others...
    2007 (English)In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 362, no 2-3, p. 215-221Article in journal (Refereed) Published
    Abstract [en]

    Ion micro beam analysis has been applied to the investigation of plasma deposited layers covering the divertor tiles in the JET tokamak. Since the layers are about 100 μm thick they are too thick to be completely investigated by ordinary ion beam analysis. Cross sections of the layers were prepared by cutting and polishing. Elemental depth profiles were determined from the two dimensional images that could be derived by nuclear reaction analysis and resonant backscattering spectrometry, using ion beams focused to a few μm spot size. A combination of analysis methods are shown, which allow measurements of the concentration profiles of carbon, beryllium, deuterium, oxygen and stainless steel components at levels of a few percent, with an accuracy better than 10%.

    Keywords
    Divertor, Nuclear fusion reactor, Tokamak, Plasma deposition, Cross section (collision), Nuclear reaction
    National Category
    Physical Sciences Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-26270 (URN)10.1016/j.jnucmat.2007.01.046 (DOI)000246895400013 ()
    Available from: 2007-02-15 Created: 2007-02-15 Last updated: 2017-12-07Bibliographically approved
    5. Cross sections of deposited layers investigated by micro nuclear reaction analysis
    Open this publication in new window or tab >>Cross sections of deposited layers investigated by micro nuclear reaction analysis
    (English)Article in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-128874 (URN)
    Available from: 2010-07-29 Created: 2010-07-29 Last updated: 2010-08-19Bibliographically approved
    6. Nuclear micro-beam analysis of deuterium distribution in carbon fibre composites for controlled fusion devices
    Open this publication in new window or tab >>Nuclear micro-beam analysis of deuterium distribution in carbon fibre composites for controlled fusion devices
    2010 (English)In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 268, no 11-12, p. 1833-1837Article in journal (Refereed) Published
    Abstract [en]

    Probes made of carbon fibre composite NB41 were exposed to deuterium plasmas in the TEXTOR tokamak and in a simulator of plasma-wall interactions, PISCES. The aim was to assess the deuterium retention and its lateral and depth distribution. The analysis was performed by means of D(He-3, p)4He and C-12(He-3, p)14N nuclear reactions analysis using a standard (1 mm spot) and micro-beam (20 mu m resolution). The measurements have revealed non uniform distribution of deuterium atoms in micro-regions: differences by a factor of 3 between the maximum and minimum deuterium concentrations. The differences were associated with the orientation and type of fibres for samples exposed in PICSES. For surface structure in the erosion zone of samples exposed to a tokamak plasma the micro-regions were more complex. Depth profiling has indicated migration of fuel into the bulk of materials.

    Place, publisher, year, edition, pages
    Amsterdam: Elsevier, 2010
    Keywords
    Nuclear reaction analysis, Micro-beam, Deuterium, Tokamak, Carbon composites
    National Category
    Fusion, Plasma and Space Physics
    Identifiers
    urn:nbn:se:uu:diva-128872 (URN)10.1016/j.nimb.2010.02.024 (DOI)000278702300031 ()
    Available from: 2010-07-29 Created: 2010-07-29 Last updated: 2017-12-12Bibliographically approved
    7. An Overview of Nuclear Micro beam Analysis of Surface and Bulk Fuel Retention in Carbon-Fibre Composites from Tore Supra
    Open this publication in new window or tab >>An Overview of Nuclear Micro beam Analysis of Surface and Bulk Fuel Retention in Carbon-Fibre Composites from Tore Supra
    Show others...
    2011 (English)In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 451, no 1, p. s764-s764Article in journal (Refereed) Published
    Abstract [en]

    Surface and bulk retention of deuterium in tiles of the pump limiter from Tore Supra was examined with nuclear reaction analysis using both standard and micro-beam techniques. The aim was to determine the variations in the content and distribution of fuel species in carbon-fibre composites. On plasma-facing surfaces from the deposition zone, the D content reaches 2.5 × 1019 cm−2 in about 8 μm thick top layer, but lateral differences reach even more than one order of magnitude. This is also measured in the erosion zone: 6.6 × 1017 cm−2 to 7.7 × 1018 cm−2 D atoms. Bulk content was examined on cross-sections opened by fracturing the tiles. Fuel is detected up to the depth of 1–1.5 mm beneath the plasma-facing surface in tiles from both the erosion and deposition zones. It occurs in bands, about 100 μm wide and several mm long, roughly parallel to the original plasma-facing surface.

    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-128873 (URN)10.1016/j.jnucmat.2010.10.044 (DOI)000298128100173 ()
    Available from: 2010-07-29 Created: 2010-07-29 Last updated: 2017-12-12Bibliographically approved
  • 11.
    Petersson, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Bergsåker, H.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Coad, J. P.
    Koivuranta, S.
    Likonen, J.
    Ion beam micro analysis of deposits at tokamak divertor surfaces2010In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 268, no 11-12, p. 1838-1841Article in journal (Refereed)
  • 12.
    Petersson, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Kreter, A.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Rubel, M.
    Nuclear micro-beam analysis of deuterium distribution in carbon fibre composites for controlled fusion devices2010In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 268, no 11-12, p. 1833-1837Article in journal (Refereed)
    Abstract [en]

    Probes made of carbon fibre composite NB41 were exposed to deuterium plasmas in the TEXTOR tokamak and in a simulator of plasma-wall interactions, PISCES. The aim was to assess the deuterium retention and its lateral and depth distribution. The analysis was performed by means of D(He-3, p)4He and C-12(He-3, p)14N nuclear reactions analysis using a standard (1 mm spot) and micro-beam (20 mu m resolution). The measurements have revealed non uniform distribution of deuterium atoms in micro-regions: differences by a factor of 3 between the maximum and minimum deuterium concentrations. The differences were associated with the orientation and type of fibres for samples exposed in PICSES. For surface structure in the erosion zone of samples exposed to a tokamak plasma the micro-regions were more complex. Depth profiling has indicated migration of fuel into the bulk of materials.

  • 13.
    Petersson, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Cross sections of deposited layers investigated by micro nuclear reaction analysisArticle in journal (Refereed)
  • 14.
    Ramström, Margareta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Hagman, Charlotte
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Tsybin, Youri O
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Markides, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Håkansson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Salehi, Albert
    Department of Pharmacology, Institute of Physiological Sciences, Lund University.
    Lundquist, Ingmar
    Department of Pharmacology, Institute of Physiological Sciences, Lund University.
    Håkanson, Rolf
    Department of Pharmacology, Institute of Physiological Sciences, Lund University.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    A novel mass spectrometric approach to the analysis of hormonal peptides in extracts of mouse pancreatic islets2003In: European Journal of Biochemistry, ISSN 0014-2956, E-ISSN 1432-1033, Vol. 270, no 15, p. 3146-3152Article in journal (Refereed)
    Abstract [en]

    Liquid chromatography mass spectrometry (LC-MS) is a valuable tool in the analysis of proteins and peptides. The combination of LC-MS with different fragmentation methods provides sequence information on components in complex mixtures. In this work, on-line packed capillary LC electrospray ionization Fourier transform ion cyclotron resonance MS was combined with two complementary fragmentation techniques, i.e. nozzle-skimmer fragmentation and electron capture dissociation, for the determination of hormonal peptides in an acid ethanol extract of mouse pancreatic islets. The most abundant peptides, those derived from proinsulin and proglucagon, were identified by their masses and additional sequence-tag information established their identities. Interestingly, the experiments demonstrated the presence of truncated C-peptides, des-(25-29)-C-peptide and des-(27-31)-C-peptide. These novel findings clearly illustrate the potential usefulness of the described technique for on-line sequencing and characterization of peptides in tissue extracts.

  • 15.
    Sadiq, Muhammad Waqas
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Salehpour, Mehran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Forsgård, Niklas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Hammarlund-Udenaes, Margareta
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences.
    Morphine brain pharmacokinetics at very low concentrations studied with Accelerator Mass Spectrometry and Liquid Chromatography-tandem Mass Spectrometry2011In: Drug Metabolism And Disposition, ISSN 0090-9556, E-ISSN 1521-009X, Vol. 39, no 2, p. 174-179Article in journal (Refereed)
    Abstract [en]

    Morphine has been predicted to show nonlinear blood-brain barrier (BBB) transport at lower concentrations. Present study investigated the possibility of separating active influx of morphine from its efflux by using very low morphine concentrations, and to compare AMS with LC-MS/MS as method for analysing microdialysis samples. A 10-min bolus infusion of morphine, followed by a constant-rate infusion, was given to male rats (n=6) to achieve high (250 ng.ml(-1)), medium (50 ng.ml(-1)) and low (10 ng.ml(-1)) steady-state plasma concentrations (C(ss)). An additional rat received infusions to achieve low (10 ng.ml(-1)), very low (2 ng.ml(-1)) and ultra low (0.4 ng.ml(-1)) concentrations. Unbound morphine concentrations from brain extracellular fluid and blood were sampled with microdialysis and analysed by LC-MS/MS and AMS. The average K(p,uu) for the low and medium steady-state levels were 0.22±0.08 and 0.21±0.05, when measured with AMS (NS; p=0.5). For the medium and high steady-state levels, K(p,uu) values were 0.24±0.05 and 0.26±0.05, measured with LC-MS/MS (NS; p=0.2). For the low, very low and ultra low levels, K(p,uu) values were 0.16±0.01, 0.16±0.02 and 0.18±0.03, respectively, measured with AMS. The medium-concentration K(p,uu) values were, on average, 16% lower with AMS than with LC-MS/MS. There were no significant changes in K(p,uu) over a 625-fold concentration range (0.4-250 ng.ml(-1)). It was not possible to separate active uptake transport from active efflux using these low concentrations. The two analytical methods provided indistinguishable results for blood plasma concentrations, but differed by up to 38% for microdialysis samples; however, this did not affect our conclusions.

  • 16.
    Salehpour, Mehran
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Ekblom, Jonas
    Sabetsky, Vladimir
    Håkansson, Karl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Accelerator mass spectrometry offers new opportunities for microdosing of peptide and protein pharmaceuticals2010In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 24, no 10, p. 1481-1489Article in journal (Refereed)
    Abstract [en]

    Accelerator Mass Spectrometry (AMS) is an ultra-sensitive analytical method which has been instrumental in developing microdosing as a strategic tool in early drug development. Considerable data is available for AMS microdosing using typical pharmaceutical drugs with a molecular weight of a few hundred Daltons. The so-called biopharmaceuticals such as proteins offer interesting possibilities as drug candidates; however, experimental data for protein microdosing and AMS is scarce. The analysis of proteins in conjunction with early drug development and microdosing is overviewed and three case studies are presented on the topic. In the first case study AMS experimental data is presented, for the measured concentration of orally administered recombinant insulin in the blood stream of laboratory rabbits. Case study 2 concerns minimum sample size requirements. AMS samples normally require about 1 mg of carbon (10 mu L of blood) which makes AMS analysis unsuitable in some applications due to the limited availability of samples such as human biopsies or DNA from specific cells. Experimental results are presented where the sample size requirements have been reduced by about two orders of magnitude. The third case study concerns low concentration studies. It is generally accepted that protein pharmaceuticals may be potentially more hazardous than smaller molecules because of immunological reactions. Therefore, future first-in-man microdosing studies might require even lower exposure concentrations than is feasible today, in order to increase the safety margin. This issue is discussed based on the current available analytical capabilities.

  • 17.
    Salehpour, Mehran
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Forsgard, Niklas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Biological AMS at Uppsala University: Status report2010In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 268, no 7-8, p. 884-886Article in journal (Refereed)
    Abstract [en]

    In January 2007 a new research program was initiated at Uppsala University focusing on the biological applications of AMS. We have used a 5 MV Pelletron Tandem accelerator to study biological samples. With Microdosing applications in mind, a variety of measurements have been performed on human blood, plasma and urine that have been labeled with a C-14-labeled pharmaceutical drug covering a concentration range, spanning 3 orders of magnitude. Furthermore, by studying small sample amounts and low concentrations, we have demonstrated sensitivity in the hundred zeptomole range for a small pharmaceutical substance in human blood. Another application of interest, based on the enhanced C-14 activity from the cold war bomb-peak, is dating of DNA molecules providing fundamental data for the regenerative medicine and stem cell research community. We show data on a sensitive carrier method for measuring the isotopic ratio of small biological sample in the few mu gC range.

  • 18.
    Yeung, Maggie
    et al.
    Karolinska Insitutet, CMB.
    Sofia, Zdunek
    Karolinska Insitutet, CMB.
    Bergmann, Olaf
    Karolinska Insitutet, CMB.
    Bernard, Samuel
    Salehpour, Mehran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Alkass, Kanar
    Perl, Shira
    Tisdale, John
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Brundin, Lou
    Druid, Henrik
    Karolinska Insitutet, CMB.
    Frisén, Jonas
    Karolinska Insitutet, CMB.
    Dynamics of Oligodendrocyte Generation and Myelination in the Human Brain2014In: Cell, ISSN 0092-8674, E-ISSN 1097-4172, Vol. 159, no 4, p. 766-774Article in journal (Refereed)
    Abstract [en]

    The myelination of axons by oligodendrocytes has been suggested to be modulated by experience, which could mediate neural plasticity by optimizing the performance of the circuitry. We have assessed the dynamics of oligodendrocyte generation and myelination in the human brain. The number of oligodendrocytes in the corpus callosum is established in childhood and remains stable after that. Analysis of the integration of nuclear bomb test-derived 14C revealed that myelin is exchanged at a high rate, whereas the oligodendrocyte population in white matter is remarkably stable in humans, with an annual exchange of 1/300 oligodendrocytes. We conclude that oligodendrocyte turnover contributes minimally to myelin remodeling in human white matter and that this instead may be carried out by mature oligodendrocytes, which may facilitate rapid neural plasticity.

1 - 18 of 18
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