| 1. |
- Andersson, Mike, et al.
(författare)
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Development of a ChemFET sensor with molecular films of porphyrins as sensitive layer
- 2001
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Ingår i: Sensors and actuators. B, Chemical. - 0925-4005 .- 1873-3077. ; 77:1-2, s. 567-571
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Tidskriftsartikel (refereegranskat)abstract
- The interaction of chemical species with molecular films of porphyrins causes variations of the work function of the film itself, as it has been recently demonstrated by using the Kelvin probe technique. This characteristic makes porphyrins films suitable to be used as sensitive layers in ChemFET sensors. In this paper, we present a preliminary report about the fabrication and testing of such gas sensitive devices. The technological solutions towards an optimised device are also illustrated and discussed. © 2001 Elsevier Science B.V.
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| 2. |
- Andersson, M, et al.
(författare)
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Isospin resolved double pion production in the reaction p+d -> He-3+2 pi
- 2000
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Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 485:4, s. 327-333
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Tidskriftsartikel (refereegranskat)abstract
- Neutral and charged two-pion production in p + d --> He-3 + 2 pi reactions has been studied at CELSIUS at a proton beam energy of 477 MeV. The total cross section for double pion production is 0.22 +/- 0.03 mu b. The ratio of the cross sections for the pr
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| 3. |
- Andersson, M, et al.
(författare)
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Pionic fusion close to threshold: d+alpha -> Li-6*+pi(0) at CELSIUS
- 2000
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Ingår i: ACTA PHYSICA POLONICA B. - : ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS. - 0587-4254. ; 31:10-11, s. 2343-2347
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Tidskriftsartikel (refereegranskat)abstract
- The isobaric analogue state of the ground state of the halo nucleus He-6 in Li-6 has been studied in a pionic fusion experiment at the CELSIUS storage ring facility in Uppsala, Sweden. The Li-6 ions were detected in a zero-degree spectrometer situated in
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| 4. |
- Andersson, M, et al.
(författare)
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Pionic fusion to a halo state, the d(alpha, Li-6*)pi(0) reaction studied close to threshold
- 2000
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Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 481:2-4, s. 165-170
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Tidskriftsartikel (refereegranskat)abstract
- The d(alpha,Li-6(3.56)*)pi(0) reaction has been studied at E-c.m. = 1.2 and 1.9 MeV above threshold with an alpha-particle beam incident on a deuterium cluster-jet target in CELSIUS. Complete differential cross sections were measured at both energies, int
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| 5. |
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| 6. |
- Andersson, M, et al.
(författare)
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The exclusive p plus d -> He-3+2 pi reaction at CELSIUS
- 2000
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Ingår i: ACTA PHYSICA POLONICA B. - : ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS. ; , s. 2123-2126
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Konferensbidrag (refereegranskat)abstract
- Neutral and charged two-pion production in p + d --> He-3 --> 2 pi reactions has been studied at a proton beam energy of 477 MeV. The total cross section for double pion production is 0.22 +/- 0.03 mub. The ratio of the cross sections for the production o
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| 7. |
- Bargholtz, C, et al.
(författare)
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Using a CdTe detector for Te-125 Mossbauer Spectroscopy: Application to the f-factor in Mg3TeO6
- 2000
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Ingår i: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS. - : ELSEVIER SCIENCE BV. - 0168-583X. ; 170:1-2, s. 239-244
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Tidskriftsartikel (refereegranskat)abstract
- An apparatus for Mossbauer spectroscopy has been developed with a cadmium telluride (CdTe) gamma-ray detector. Complete data regarding gamma-ray energy, source velocity, temperature and real time are stored for off-line analysis. The apparatus has been us
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| 8. |
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| 9. |
- Johansson, A., et al.
(författare)
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Synthesis and photophysics of one mononuclear Mn(III) and one dinuclear Mn(III,III) complex covalently linked to a ruthenium(II) tris(bipyridyl) complex
- 2003
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 42, s. 7502-7511
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Tidskriftsartikel (refereegranskat)abstract
- The preparation of donor (D)-photosensitizer (S) arrays, consisting of a manganese complex as D and a ruthenium tris(bipyridyl) complex as S has been pursued. Two new ruthenium complexes containing coordinating sites for one (2a) and two manganese ions (3a) were prepared in order to provide models for the donor side of photosystem II in green plants. The manganese coordinating site consists of bridging and terminal phenolate as well as terminal pyridyl ligands. The corresponding ruthenium-manganese complexes, a manganese monomer 2b and dimer 3b, were obtained. For the dimer 3b, our data suggest that intramolecular electron transfer from manganese to photogenerated ruthenium(III) is fast, k(ET) > 5 x 10(7) s(-1).
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| 10. |
- Licence, S, et al.
(författare)
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The VpreB1 enhancer drives developmental stage-specific gene expression in vivo
- 2003
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Ingår i: European Journal of Immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 33:4, s. 1117-1126
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Tidskriftsartikel (refereegranskat)abstract
- In adult mice, the VpreB genes are expressed in bone marrow progenitor (pro-) and precursor (pre-) B cells. As part of the pre-B cell receptor, the proteins are crucial for the proliferation of these cells and consequently normal B lymphocyte development. Using cell lines, we identified a lineage- and developmental-stage-specific VpreB1 enhancer. Here, we analyze its specificity in vivo by generating transgenic mice in which expression of a reporter gene (human CD122) is regulated by the VpreB1 enhancer in the context of its own promoter. All transgenic lines expressed the reporter gene in the bone marrow in a copy number-independent manner, whereas expression levels were integration site-dependent. While the enhancer is not tissue specific, within the B cell lineage the expression pattern of human CID122 mimicked that of endogenous VpreB1. Thus, low levels were detected in pro-B cells, high levels in pre-BI and slightly lower levels in pre-BII cells; no expression was detected in immature/mature B cells. Furthermore, when in vitro cultured transgenic pre-B cells differentiated into immature B cells there was concomitant down-regulation of human CD122 and endogenous VpreB1. Thus the VpreB1 enhancer is sufficient to ensure developmental stage-specific expression of a reporter gene in B lymphocytes in vivo.
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| 11. |
- Lloyd-Spets, Anita, et al.
(författare)
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SiC based field effect gas sensors for industrial applications
- 2001
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Ingår i: Physica status solidi. A, Applied research. - 0031-8965 .- 1521-396X. ; 185:1, s. 15-25
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Tidskriftsartikel (refereegranskat)abstract
- The development and field-testing of high-temperature sensors based on silicon carbide devices have shown promising results in several application areas. Silicon carbide based field-effect sensors can be operated over a large temperature range, 100-600 degreesC, and since silicon carbide is a chemically very inert material these sensors can be used in environments like exhaust gases and flue gases from boilers. The sensors respond to reducing gases like hydrogen, hydrocarbons and carbon monoxide. The use of different temperatures, different catalytic metals and different structures of the gate metal gives selectivity to different gases and arrays of sensors can be used to identify and monitor several components in gas mixtures. MOSFET sensors based on SIC combine the advantage of simple circuitry with a thicker insulator, which increases the long term stability of the devices. In this paper we describe silicon carbide MOSFET sensors and their performance and give: examples of industrial applications such as monitoring of car exhausts and flue gases. Chemometric methods have been used for the evaluation of the data.
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| 12. |
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| 13. |
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| 14. |
- O'Shea, J. N., et al.
(författare)
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Hydrogen-bond induced surface core-level shift in isonicotinic acid
- 2001
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1089-5647 .- 1520-6106 .- 1520-5207. ; 105:10, s. 1917-1920
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Tidskriftsartikel (refereegranskat)abstract
- Intermolecular hydrogen-bonding in thick films of isonicotinic acid evaporated onto rutile TiO2(110) has been investigated with X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The rate of deposition is found to be a key factor in overcoming the kinetic barriers to extensive hydrogen-bond formation, which, when present, gives rise to large energy shifts between bulk and surface in both the N1s XPS and XAS. The origin of the surface core-level shift is attributed to the presence of non-hydrogen-bonded nitrogen atoms in the surface layer.
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| 15. |
- Puglia, C, et al.
(författare)
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XPS and XAS study of oxygen coadsorbed with a dispersed phase of K on graphite
- 2001
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Ingår i: SURFACE SCIENCE. - : ELSEVIER SCIENCE BV. ; 488:1-2
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The adsorption of O-2 onto a dispersed (low coverage) phase of K on graphite has been characterized by X-ray photoemission and X-ray absorption spectroscopy. We identify two oxygen adsorption phases before physisorbed oxygen appears. The first species dom
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| 16. |
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| 17. |
- Schmitt, H., et al.
(författare)
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Synthesis, redox properties, and EPR spectroscopy of manganese(III) complexes of the ligand N,N-bis(2-hydroxybenzyl)-N '-2-hdroxybenzylidene-1,2-diaminoethane : Formation of mononuclear, dinuclear, and even higher nuclearity complexes
- 2002
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Ingår i: Chemistry - A European Journal. - 0947-6539 .- 1521-3765. ; 8:16, s. 3757-3768
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis and characterization of the title trisphenolate ligand are described. From its reaction with manganese(iii) three complexes were isolated. The crystal structures revealed one pentacoordinate monomer and two similar dimers with different solvents of crystallization. In the dimers the metal ions are hexacoordinate and connected through bridging of two phenolates. A combination of electrochemistry and EPR spectroscopy showed that, in acetonitrile, the isolated batches were all identical and mainly monomeric, indicating that the mononuclear complex is in equilibrium with the dimer and perhaps also with complexes of higher nuclearity, as suggested by the detection of both the trimer and the tetramer by electrospray ionization mass spectrometry (ESI-MS). The successful use of the monomer batch as an epoxidation catalyst indicated that a high-valent manganese-oxo species can be formed, although it is probably short-lived. This is also suggested by EPR studies of the species formed by electrochemical oxidation of the complex. Upon one-electron oxidation, a manganese(iv) species was formed, which was at least partly converted to another species containing a phenoxy radical.
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| 18. |
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| 19. |
- Sun, Licheng C., et al.
(författare)
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Towards an artificial model for Photosystem II : a manganese(II,II) dimer covalently linked to ruthenium(II) tris-bipyridine via a tyrosine derivative
- 2000
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Ingår i: Journal of Inorganic Biochemistry. - 0162-0134 .- 1873-3344. ; 78:1, s. 15-22
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Tidskriftsartikel (refereegranskat)abstract
- In order to model the individual electron transfer steps from the manganese cluster to the photooxidized sensitizer P-680(+) in Photosystem II (PS II) in green plants, the supramolecular complex 4 has been synthesized. In this complex, a ruthenium(II) tris-bipyridine type photosensitizer has been linked to a manganese(II) dimer via a substituted L-tyrosine, which bridges the manganese ions. The trinuclear complex 4 was characterized by electron paramagnetic resonance (EPR) and electrospray ionization mass spectrometry (ESI-MS). The excited state lifetime of the ruthenium tris-bipyridine moiety in 4 was found to be about 110 ns in acetonitrile, Using flash photolysis in the presence of an electron acceptor (methylviologen), it was demonstrated that in the supramolecular complex 4 an electron was transferred from the excited state of the ruthenium tris-bipyridine moiety to methylviologen, forming a methylviologen radical and a ruthenium(III) tris-bipyridine moiety. Next, the Ru(III) species retrieved the electron from the manganese(II/II) dimer in an intramolecular electron transfer reaction with a rate constant k(ET)>1.0X10(7) s(-1), generating a manganese(II/III) oxidation state and regenerating the ruthenium(II) photosensitizer. This is the first example of intramolecular electron transfer in a supramolecular complex, in which a manganese dimer is covalently linked to a photosensitizer via a tyrosine unit, in a process which mimics the electron transfer on the donor side of PS II.
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