| 1. |
- Gahn, C, et al.
(författare)
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Generating positrons with femtosecond-laser pulses
- 2000
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 77:17, s. 2662-2664
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Tidskriftsartikel (refereegranskat)abstract
- Utilizing a femtosecond table-top laser system, we have succeeded in converting via electron acceleration in a plasma channel, low-energy photons into antiparticles, namely positrons. The average intensity of this source of positrons is estimated to be equivalent to 2x10(8) Bq and it exhibits a very favorable scaling for higher laser intensities. The advent of positron production utilizing femtosecond laser pulses may be the forerunner to a table-top positron source appropriate for applications in material science, and fundamental physics research like positronium spectroscopy. (C) 2000 American Institute of Physics. [S0003-6951(00)00143-1].
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| 2. |
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| 3. |
- Sorensen, S. L., et al.
(författare)
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Femtosecond pump-probe photoelectron spectroscopy of predissociative Rydberg states in acetylene
- 2000
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 112:18, s. 8038-8042
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Tidskriftsartikel (refereegranskat)abstract
- We employ a pump-probe approach to molecular photoionization to study fast dissociation of Rydberg states in acetylene. By using time-resolved photoelectron spectroscopy to study the electronic state of the resulting ions we are able to monitor the system continuously during dissociation or rearrangement. We find that the predissociative lifetime for the 3R‴ (v′2 = 1) Rydberg state is about 150 fs. We demonstrate a powerful new technique using time-correlated femtosecond harmonic generation and laser light pulses to study the time evolution of ultrafast dynamic processes in molecules.
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| 4. |
- Bauer, Hjärtcentrum, et al.
(författare)
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Monitoring referral and treatment in soft tissue sarcoma : Study based on 1,851 patients from the Scandinavian Sarcoma Group Register
- 2001
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Ingår i: Acta Orthopaedica Scandinavica. - : Medical Journals Sweden AB. - 0001-6470. ; 72:2, s. 150-159
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Tidskriftsartikel (refereegranskat)abstract
- This report is based on 1.851 adult patients with soft tissue sarcoma (STS) of the extremities or trunk wall diagnosed between 1986 and 1997 and reported from all tertiary referral centers in Norway and Sweden. The median age at diagnosis was 65 years and the male-to-female ratio was 1.1:1. One third of the tumors were subcutaneous, one third deep, intramuscular and one third deep, extramuscular. The median size was 7 (1-35) cm and 75% were high grade (III-IV). Metastases at presentation were diagnosed in 8% of the patients. Two thirds of STS patients were referred before surgery and the referral practices have improved during the study. The preoperative morphologic diagnosis was made with fine-needle aspiration cytology in 81%, core-needle biopsy in 9% and incisional biopsy in 10%. The frequency of amputations has decreased from 15% in 1986-88 to 9% in 1995-1997. A wide surgical margin was achieved in 77% of subcutaneous and 60% of deep-seated lesions. Overall, 24% of operated STS patients had adjuvant radiotherapy. The use of such therapy at sarcoma centers increased from 20% 1986-88 to 30% in 1995-97. Follow-up has been reported in 96% of the patients. The cumulative local recurrence rate was 0.20 at 5 years and 0.24 at 10 years. The 5-year metastasis-free survival rate was 0.70.
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| 5. |
- Bergman, Jan, et al.
(författare)
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Synthesis of indolocarbazole quinones; potent aryl hydrocarbon receptor ligands
- 2002
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Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:7, s. 1443-1452
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Tidskriftsartikel (refereegranskat)abstract
- Syntheses of indolo[2,3-b]carbazole-6,12-dione and the isomeric indolo[3,2-b]carbazole-6,12-dione, an extremely efficient inducer of the aryl hydrocarbon (Ah) receptor are described. Initial oxidation of the parent indolo[3,2-b]carbazole followed by several different ring-closing strategies produced the latter compound. Entries into syntheses of unsymmetrical 6,12-disubstituted indolo[2,3-b]carbazoles are also described.
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| 6. |
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| 7. |
- Einbeigi, Z., et al.
(författare)
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A founder mutation of the BRCA1 gene in Western Sweden associated with a high incidence of breast and ovarian cancer
- 2001
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Ingår i: European Journal of Cancer. - : Elsevier. - 0959-8049 .- 1879-0852. ; 37:15, s. 1904-1909
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to describe and characterise a founder mutation of the BRCA1 gene in western Sweden. Of 62 families screened for BRCA mutations, 24 had BRCA1 mutations and two had BRCA2 mutations. Tumours that occurred in family members were histologically reviewed and mutational status was analysed using archival paraffin-embedded tissues. The same BRCA1 mutation, 3171ins5, was found in 16 families who were clustered along the western coast of Sweden. Mutation analysis revealed a maternal linkage in 13 families and a paternal linkage in 3. There was complete agreement between mutation analysis results obtained from blood and archival tissues. The penetrance of breast or ovarian cancer by age 70 years was estimated to be between 59 and 93%. There were no differences in survivals between breast or ovarian cancer patients with the mutation and age-matched controls. Thus, a predominant BRCA1 gene founder mutation associated with a high risk of breast and ovarian cancer has been identified and found to occur in a restricted geographical area, thereby allowing timely and cost-effective mutation screening using blood samples or archival histological material.
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| 8. |
- Gahn, C, et al.
(författare)
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Generation of MeV electrons and positrons with femtosecond pulses from a table-top laser system
- 2002
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 9:3, s. 987-999
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Tidskriftsartikel (refereegranskat)abstract
- In experiments, the feasibility was demonstrated of generating multi-MeV electrons in a form of a collimated beam utilizing a table-top laser system delivering 200 fs pulses with P-L=1.2 TW and 10 Hz capability. The method uses the process of relativistic self-channeling in a high-density gas jet producing electron densities in the range of 3x10(19)-6x10(20) cm(-3). In a thorough investigation, angularly resolved and absolutely calibrated electron spectra were measured and their dependence on the plasma density, laser intensity, and gas medium was studied. For the optimum electron density of n(e)=2x10(20) cm(-3) the effective temperature of the electron energy distribution and the channel length exhibit a maximum of 5 MeV and 400 mum respectively. The laser-energy to-MeV-electron efficiency is estimated to be 5%. In a second step, utilizing the multi-MeV electron beam anti-particles, namely positrons, were successfully generated in a 2 mm Pb converter. The average intensity of this new source of positrons is estimated to be equivalent to a radioactivity of 2x10(8) Bq and it exhibits a very favorable scaling for higher laser intensities. (C) 2002 American Institute of Physics.
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| 9. |
- Gedda, Hans, et al.
(författare)
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Energy redistribution during CO2 laser cladding
- 2001
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Ingår i: Congress proceedings. - Orlando, Fla : Laser institute of America. - 912035730 ; , s. 549-558
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Konferensbidrag (refereegranskat)abstract
- This paper examines the factors that effect the efficiency of the CO sub 2 -laser powder cladding process. By theoretical calculation and experimental work it has been possible to identify how much of the original laser energy contributes to the cladding process and how much is lost to the surrounding environment by reflection, radiation, convection etc. Every aspect of energy redistribution has been analysed and quantified and this has lead to a deeper understanding of the process. The paper concludes with a number of suggestions for improving the efficiency of blown powder laser cladding
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| 10. |
- Gedda, Hans, et al.
(författare)
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Energy redistribution during CO2 laser cladding
- 2002
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Ingår i: Journal of laser applications. - : Laser Institute of America. - 1042-346X .- 1938-1387. ; 14:2, s. 78-82
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Tidskriftsartikel (refereegranskat)abstract
- This article examines the factors that effect the efficiency of the CO sub 2 -laser powder cladding process. By theoretical calculation and experimental work it has been possible to identify how much of the original laser energy contributes to the cladding process and how much is lost to the surrounding environment by reflection, radiation, convection, etc. Every aspect of energy redistribution has been analyzed and quantified and this has led to a deeper understanding of the process. The article concludes with a number of suggestions for improving the efficiency of blown powder laser cladding.
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