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| 7. |
- Hammarstrom, L, et al.
(författare)
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Mimicking photosystem II reactions in artificial photosynthesis
- 1999
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Ingår i: ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS. - : R OLDENBOURG VERLAG. - 0942-9352. ; 213, s. 157-163
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Tidskriftsartikel (refereegranskat)abstract
- The paper describes a project aiming at the construction of functional mimics of the oxygen evolving complex of Photosystem II, coupled to photoinduced charge separation. Biomimetic electron donors - manganese complexes and tyrosine - have been linked to
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| 12. |
- Ahlstrand, Elisabeth, 1947-, et al.
(författare)
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Teacher Knowledge Development in a Social and Individual Context
- 1996
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Ingår i: Changing Research and Practice. Teachers' Professionalism, Identities and Knowledge. - London, Washington : Falmer Press. - 075070585X - 0750705868
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 17. |
- Bäck, S A, et al.
(författare)
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Verification of single beam treatment planning using a ferrous dosimeter gel and MRI (FeMRI)
- 1998
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Ingår i: Acta Oncologica. - 0284-186X. ; 37:6, s. 6-561
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Tidskriftsartikel (refereegranskat)abstract
- A method for analysing and comparing treatment planning system (TPS) data and ferrous dosimeter gel measurements evaluated with MRI (FeMRI) was developed, including image processing to final absorbed dose images. Measurements were analysed according to this method and FeMRI data were thereby compared with the TPS-calculated dose distribution. For photons, differences between FeMRI- and TPS dose data were mainly within +/- 2%. Minor shortcomings found in both the FeMRI system and the TPS are explained and discussed. For electron beams, there was an overall good agreement. It was found that the TPS underestimates the lateral scattering dose outside the primary beam, but the reported dose difference corresponds to a small spatial deviation (less than 2 mm). It is important to consider this single beam data comparison when the method is extended to more complicated situations, for example when using several beams.
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| 18. |
- Bäck, Sven, et al.
(författare)
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Improvements in absorbed dose measurements for external radiation therapy using ferrous dosimeter gel and MR imaging (FeMRI)
- 1998
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 43, s. 261-
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Tidskriftsartikel (refereegranskat)abstract
- A ferrous gel, based on ferrous (Fe) sulphate and agarose, was used with a clinical magnetic resonance imaging (MRI) scanner to obtain relative dose distribution data from therapeutic photon and electron beams. The FeMRI gel was scanned using a new MRI acquisition protocol optimized for T1 measurements. Thorough comparisons with silicon semiconductor detector and ionization chamber measurements, as well as with Monte Carlo calculations, were performed in order to quantify the improvements obtained using FeMRI for dose estimations. Most of the relative doses measured with FeMRI were within 2% of the doses measured with other methods. The larger discrepancies (2-4%) found at shallow depths are discussed. The uncertainty in relative dose measurements using FeMRI was significantly improved compared with previously reported results (5-10%, one standard deviation, 1 SD), and is today between 1.6% and 3.3% (depending on dose level, 2 SD). This corresponds to an improvement in the minimum detectable dose (3 SD above background) from approximately 2 Gy to better than 0.6 Gy. The results obtained in this study emphasize the importance of obtaining basic FeMRI dose data before the method is extended to complicated treatment regimes.
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| 21. |
- Eriksson, Britt-Marie, et al.
(författare)
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A prospective study of rapid methods of detecting cytomegalovirus in the blood of renal transplant recipients in relation to patient and graft survival
- 1996
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Ingår i: Clinical Transplantation. - 0902-0063 .- 1399-0012. ; 10:6 Pt 1, s. 494-502
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Tidskriftsartikel (refereegranskat)abstract
- Eighty-five renal transplant recipients were prospectively monitored for CMV infection up to 4 months post-transplantation by virus isolation from leukocytes, CMV antigen detection (pp65) in peripheral blood leukocytes (PBL), polymerase chain reaction (PCR) of alkaline treated plasma (P-PCR), PCR of extracted DNA from PBL (L-PCR) and serology. Additionally univariate and multivariate analyses of risk factors for patient and graft survival up to 4 yr post-transplantation were performed. The incidence of CMV infection was 78% and of CMV disease 33%. Antigen detection in PBL was positive before or at onset of symptoms in 23/24 (96%) evaluable patients with CMV disease. The corresponding figures for virus isolation were 22/24 (92%), P-PCR 21/24 (88%) and for L-PCR 18/24 (75%). The percentage of negative samples in patients without CMV disease was 89% for the antigen test, 92% for L-PCR and 83% for virus isolation and P-PCR. One rapid test (antigen test, P-PCR or L-PCR) was positive at a median of 16 d before the onset of symptoms. The antigen test was generally the first rapid test to become positive. CMV disease did not affect graft survival in the multivariate analysis but was associated with decreased patient survival.
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| 22. |
- GHANDOUR, AM, et al.
(författare)
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MOSSBAUER STUDY OF FE-57 DOPED YBA2CU4O8 AND Y2BA4CU7O15-Y SUPERCONDUCTORS
- 1995
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Ingår i: PHYSICA SCRIPTA. - : ROYAL SWEDISH ACAD SCIENCES. - 0281-1847. ; 52:4, s. 395-402
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The effect of Fe doping in high temperature superconductors (YBa2Cu4-xFexO8)-Fe-57 (x = 0.02, 0.04, 0.06, 0.08) and (Y2B4Cu6.86Fe0.14O14.9)-Fe-57 have been studied by Fe-57 Mossbauer spectroscopy at various temperatures. All room temperature spectra for t
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| 23. |
- GUDMUNDSSON, GH, et al.
(författare)
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Structure of the gene for porcine peptide antibiotic PR-39, a cathelin gene family member: comparative mapping of the locus for the human peptide antibiotic FALL-39
- 1995
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 92:15, s. 7085-7089
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Tidskriftsartikel (refereegranskat)abstract
- PR-39 is a porcine 39-aa peptide antibiotic composed of 49% proline and 24% arginine, with an activity against Gram-negative bacteria comparable to that of tetracycline. In Escherichia coli, it inhibits DNA and protein synthesis. PR-39 was originally isolated from pig small intestine, but subsequent cDNA cloning showed that the gene is expressed in the bone marrow. The open reading frame of the clone showed that PR-39 is made as 173-aa precursor whose proregion belongs to the cathelin family. The PR39 gene, which is rather compact and spans only 1784 bp has now been sequenced. The coding information is split into four exons. The first exon contains the signal sequence of 29 residues and the first 37 residues of the cathelin propart. Exons 2 and 3 contain only cathelin information, while exon 4 codes for the four C-terminal cathelin residues and the mature PR-39 peptide extended by three residues. The sequenced upstream region (1183 bp) contains four potential recognition sites for NF-IL6 and three for APRF, transcription factors known to regulate genes for both cytokines and acute phase response factors. Genomic hybridizations revealed a fairly high level of restriction fragment length polymorphism and indicated that there are at least two copies of the PR39 gene in the pig genome. PR39 was mapped to pig chromosome 13 by linkage and in situ hybridization mapping. The gene for the human peptide antibiotic FALL-39 (also a member of the cathelin family) was mapped to human chromosome 3, which is homologous to pig chromosome 13.
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| 24. |
- Ivarson, A., et al.
(författare)
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Reflection phenomena in Co2 laser cutting
- 1997
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Ingår i: Proceedings of the 6th Nordic Laser Material Processing Conference, Luleå, Sweden, August 27-29, 1997. - Luleå : Luleå tekniska universitet. ; , s. 16-24
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Konferensbidrag (refereegranskat)
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| 26. |
- Johansson, S A, et al.
(författare)
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Dosimeter gel and MR imaging for verification of calculated dose distributions in clinical radiation therapy
- 1997
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Ingår i: Acta Oncologica. - 0284-186X. ; 36:3, s. 90-283
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Tidskriftsartikel (refereegranskat)abstract
- A dosimeter gel, based on an agarose gel infused with a ferrous sulphate solution and evaluated in a magnetic resonance scanner, was used for complete verification of calculated dose distributions. Two standard treatment procedures, treatment of cancer in the urinary bladder and treatment of breast cancer after modified radical mastectomy, were examined using pixel-by-pixel and dose volume histogram comparison. The dose distributions calculated with the dose planning system was in very good agreement with the measured ones. However, in the case of the more complicated breast cancer treatment, some discrepancies were found, mainly at the beam abutment region. This may be explained by field displacements errors and by a small limitation of the dose planning utilising small electron beams in this region. The dosimeter gel system have proven to be a useful tool for dosimetry in clinical radiation therapy applications.
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| 28. |
- LAGERKVIST, CI, et al.
(författare)
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PHYSICAL STUDIES OF ASTEROIDS .29. PHOTOMETRY AND ANALYSIS OF 27 ASTEROIDS
- 1995
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Ingår i: ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES. - : EDITIONS PHYSIQUE. - 0365-0138. ; 113:1, s. 115-129
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Tidskriftsartikel (refereegranskat)abstract
- In this paper photometry and analysis of 27 asteroids are presented. For the asteroids 21 Lutetia, 23 Thalia, 250 Bettina and 135 Hertha spin vector determinations were made. For asteroid 99 Dike we derived a rotation period of 10.35 hours and for 1280 Ba
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| 35. |
- MAGNUSSON, J, et al.
(författare)
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TIME-DEPENDENCE OF THE MAGNETIZATION OF BI2SR2CACU2O8 DISPLAYING THE PARAMAGNETIC MEISSNER EFFECT
- 1995
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Ingår i: PHYSICAL REVIEW B-CONDENSED MATTER. - : AMER INST PHYSICS. - 0163-1829. ; 52:10, s. 7675-7681
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Tidskriftsartikel (refereegranskat)abstract
- The time dependence of the magnetization of a Bi2Sr2CaCu2O8 sample displaying the paramagnetic Meissner effect has been studied as a function of field, temperature, and age of the system using superconducting quantum interference device magnetometry. The
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| 36. |
- Magnusson, Kerstin, 1957, et al.
(författare)
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Contamination and correlation with toxicity of sediment samples from the Skiagerrak and Kattegat
- 1996
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Ingår i: Journal of Sea Research. - 1385-1101. ; 35:1-3, s. 223-234
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Tidskriftsartikel (refereegranskat)abstract
- The pollution state in the Skagerrak and Kattegat was investigated by determination of pollutant concentrations and toxicity of sediment samples from 11 stations in the area. A comparison was made with the sediment from a reference site near the Faroe Islands. Polycyclic aromatic hydrocarbons (PAH) and organochlorines were determined in whole sediment and heavy metals and ammonia were analysed in filtered pore water. Toxicity was bioassayed in whole sediment with Nitocra spinipes and Daphnia magna, in pore water with Mytilus edulis larvae and in solvent extracts from sediment with tests measuring etoxyresorufin-O-deethylase (EROD) activity in Oncorhyncus mykiss and rate of denitrification. Sites close to Goteborg and in an area from the Oslo fjord to the Norwegian Trench were most polluted. Sediment from the Faroe Islands was least polluted and also least toxic. Multivariate statistical analysis indicates that the different tests were sensitive to different kinds of pollutants. Effects on mussel larvae correlated strongest with the occurrence of ammonia, manganese, cadmium and PAHs, Nitocra with alpha-hexachlorocyclohexane (HCH) and p,p'-DDD, Daphnia with arsenic and gamma-HCH, fish EROD activity with benzo[ghi]perylene and unknown compounds associated with organic carbon, and denitrification with chlordanes, dieldrin and a few PAHs. The results indicate that sampling sites close to Goteborg are so polluted that harmful effects on the ecosystem probably occur.
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| 43. |
- Magnusson, Peter, et al.
(författare)
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MRI image plane nonuniformity in evaluation of ferrous sulphate dosimeter gel (FeGel) by means of T1-relaxation time
- 1999
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Ingår i: Magnetic Resonance Imaging. - 0730-725X. ; 17:9, s. 70-1357
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Tidskriftsartikel (refereegranskat)abstract
- MR image nonuniformity can vary significantly with the spin-echo pulse sequence repetition time. When MR images with different nonuniformity shapes are used in a T1-calculation the resulting T1-image becomes nonuniform. As shown in this work the uniformity TR-dependence of the spin-echo pulse sequence is a critical property for T1 measurements in general and for ferrous sulfate dosimeter gel (FeGel) applications in particular. The purpose was to study the characteristics of the MR image plane nonuniformity in FeGel evaluation. This included studies of the possibility of decreasing nonuniformities by selecting uniformity optimized repetition times, studies of the transmitted and received RF-fields and studies of the effectiveness of the correction methods background subtraction and quotient correction. A pronounced MR image nonuniformity variation with repetition and T1 relaxation time was observed, and was found to originate from nonuniform RF-transmission in combination with the inherent differences in T1 relaxation for different repetition times. The T1 calculation itself, the uniformity optimized repetition times, nor none of the correction methods studied could sufficiently correct the nonuniformities observed in the T1 images. The nonuniformities were found to vary considerably less with inversion time for the inversion-recovery pulse sequence, than with repetition time for the spin-echo pulse sequence, resulting in considerably lower T1 image nonuniformity levels.
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| 44. |
- Magnusson, P, et al.
(författare)
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Photometric observations and modeling of asteroid 1620 Geographos
- 1996
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Ingår i: ICARUS. - : ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS. - 0019-1035. ; 123:1, s. 227-244
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Photometric observations of 1620 Geographos in 1993 and 1993 are presented and, in combination with previously published data, are used to derive models of Geographos, We estimate that the sidereal period of rotation is 0.21763860 +/- 0.00000003 days (5(h
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| 45. |
- Magnusson, Stefan, et al.
(författare)
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Soluble saccharides block the inhibition of agonist-induced human platelet aggregation observed after in vitro incubation of human platelet-rich plasma with porcine aortic endothelial cells.
- 1998
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Ingår i: Transplant international : official journal of the European Society for Organ Transplantation. - 0934-0874. ; 11:5, s. 345-52
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Tidskriftsartikel (refereegranskat)abstract
- Platelet aggregation is a prominent feature in the hyperacute process of vascularized allografts and xenografts. In a study of extracorporeal connection of pig kidneys to the blood circulation of human volunteers, we observed in one case considerable destruction of human platelets in the pig kidney without signs of hyperacute rejection or microthrombi formation. In the present study, we have investigated the agonist-induced aggregation of human platelets in mixtures with porcine aortic endothelial cells (PAEC). In vitro incubation of human platelet-rich plasma (PRP) with PAEC inhibited platelet aggregation induced by ADP, collagen and arachidonic acid in a time-dependent manner and partially inhibited adrenalin-induced aggregation. Aggregation of the human platelets could not be induced by high concentrations of ADP (20 microM) to overcome the inhibition capacity of the PAEC. The PAEC inhibiting effect could be transferred by the supernatants of PAEC/PRP and PAEC/PPP incubation mixtures. Preincubation of the PAEC with aspirin, but not with NG-methyl-L-Arg, reduced the aggregation inhibitory effect. Control experiments mixing human umbilical vein endothelial cells (HUVEC) and human PRP or mixing porcine PRP and PAEC did not elicit any inhibition of ADP-induced platelet aggregation. The aggregation inhibition effect could partially be blocked by preincubation of PRP with soluble Gal alpha 1-3Gal, Gal alpha 1-3 beta 1-4GlcNAc, lactose, galactose, and glucose, but not by lactosamine, galactosamine, or glucosamine. The Gal alpha 1-3Gal disaccharide was most effective in blocking aggregation inhibition, and to a similar extent as its ability to block the human anti-pig lymphocytotoxicity reaction. In conclusion, the data indicate that PAEC, upon stimulation by human anti-pig xenoantibodies in a nondynamic system, inhibits agonist-induced human platelet aggregation, and that this effect is probably at least partially caused by prostacyclin released from the PAEC.
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| 46. |
- Nilsson, Annika, et al.
(författare)
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Finite-element simulation of V-die bending: A comparison with experimental results
- 1997
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Ingår i: Journal of Materials Processing Technology. - : Elsevier BV. - 0924-0136 .- 1873-4774. ; 65, s. 52-58
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Forskningsöversikt (refereegranskat)abstract
- A major problem in sheet bending is to compensate for springback. Analytical descriptions are not sufficiently general to accommodate influences from the material and the geometry due to the simplifications that have to be made. Practical experiments are still needed to be able to compensate for springback. The aim of this work has been to test the finite-element method on its abilities to predict springback for free bending in a V-die. The work shows that the finite-element method can be used to predict springback off-line. The true stress-true strain curve from a tensile test is used as the material description. Springback has been studied for eight different materials of varying thickness. The process has been simulated with the code Nike2d and the results from the simulations compared with those from experiments, good correlation between the simulations and the experiments being achieved. © 1997 Elsevier Science S.A.
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