| 11. |
- Abdelsalam, UM, et al.
(författare)
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Ion-acoustic solitary waves in a dense pair-ion plasma containing degenerate electrons and positrons
- 2008
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Ingår i: Physics Letters A. - Amsterdam : Elsevier. - 0375-9601 .- 1873-2429. ; 372:22, s. 4057-4061
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Tidskriftsartikel (refereegranskat)abstract
- Fully nonlinear propagation of ion-acoustic solitary waves in a collisionless dense/quantum electron-positron-ion plasma is investigated. The electrons and positrons are assumed to follow the Thomas-Fermi density distribution and the ions are described by the hydrodynamic equations. An energy balance-like equation involving a Sagdeev-type pseudo-potential is derived. Finite amplitude solutions are obtained numerically and their characteristics are discussed. The small-but finite-amplitude limit is also considered and an exact analytical solution is obtained. The present studies might be helpful to understand the excitation of nonlinear ion-acoustic solitary waves in a degenerate plasma such as in superdense white dwarfs.
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| 12. |
- Abdelsalam, UM, et al.
(författare)
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Localized electrostatic excitations in a Thomas-Fermi plasma containing degenerate electrons
- 2008
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Ingår i: Physics of Plasmas. - Melville : American Institute of Physics (AIP). - 1070-664X .- 1089-7674. ; 15:5
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Tidskriftsartikel (refereegranskat)abstract
- By using the Thomas-Fermi electron density distribution for quantum degenerate electrons, the hydrodynamic equations for ions, and the Poisson equation, planar and nonplanar ion-acoustic solitary waves in an unmagnetized collisionless plasma are investigated. The reductive perturbation method is used to derive cylindrical and spherical Korteweg-de Vries equations. Numerical solutions of the latter are presented. The present results can be useful in understanding the features of small but finite amplitude localized ion-acoustic solitary pulses in a degenerate plasma.
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| 13. |
- Abdulla, Parosh Aziz, et al.
(författare)
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Bisimulation minimization of tree automata
- 2007
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Ingår i: International Journal of Foundations of Computer Science. - 0129-0541. ; 18:4, s. 699-713
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Tidskriftsartikel (refereegranskat)abstract
- We extend an algorithm by Paige and Tarjan that solves the coarsest stable refinement problem to the domain of trees. The algorithm is used to minimize nondeterministic tree automata (NTA) with respect to bisimulation. We show that our algorithm has an overall complexity of $O(\hat{r} m \log n)$, where $\hat{r}$ is the maximum rank of any symbol in the input alphabet, m is the total size of the transition table, and n is the number of states.
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| 14. |
- Abdulla, Parosh Aziz, et al.
(författare)
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Bisimulation minimization of tree automata
- 2006
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Ingår i: Implementation and Application of Automata. ; , s. 699-713
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Konferensbidrag (refereegranskat)abstract
- We extend an algorithm by Paige and Tarjan that solves the coarsest stable refinement problem to the domain of trees. The algorithm is used to minimize nondeterministic tree automata (NTA) with respect to bisimulation. We show that our algorithm has an overall complexity of O ((r) over cap log n), where (r) over cap is the maximum rank of any symbol in the input alphabet, m is the total size of the transition table, and n is the number of states.
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| 15. |
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| 16. |
- Aberg, Carola Höglund, et al.
(författare)
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Presence of Aggregatibacter actinomycetemcomitans in young individuals : a 16-year clinical and microbiological follow-up study.
- 2009
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Ingår i: Journal of clinical periodontology. - 1600-051X. ; 36:10, s. 815-22
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To look for clinical signs of periodontal disease in young adults who exhibited radiographic bone loss and detectable numbers of Aggregatibacter actinomycetemcomitans in their primary dentition. MATERIAL AND METHODS: Periodontal status and radiographic bone loss were examined in each of the subjects 16 years after the baseline observations. Techniques for anaerobic and selective culture, and checkerboard, were used to detect periodontitis-associated bacterial species. The isolated A. actinomycetemcomitans strains were characterized by polymerase chain reaction. RESULTS: Signs of localized attachment loss were found in three out of the 13 examined subjects. A. actinomycetemcomitans was recovered from six of these subjects and two of these samples were from sites with deepened probing depths and attachment loss. Among the isolated A. actinomycetemcomitans strains, serotypes a-c and e, but not d or f, were found. None of the isolated strains belonged to the highly leucotoxic JP2 clone, and one strain lacked genes for the cytolethal distending toxin. CONCLUSIONS: This study indicates that the presence of A. actinomycetemcomitans and early bone loss in the primary dentition does not necessarily predispose the individual to periodontal attachment loss in the permanent dentition.
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| 17. |
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| 18. |
- Abou-Hamad, Edy, et al.
(författare)
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Hydrogenation of C-60 in Peapods: Physical Chemistry in Nano Vessels
- 2009
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Ingår i: The Journal of Physical Chemistry C. - WASHINGTON, DC 20036 : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 113:20, s. 8583-8587
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogenation of C-60 molecules inside SWNT was achieved by direct reaction with hydrogen gas at elevated pressure and temperature. Evidence for the C-60 hydrogenation in peapods is provided by isotopic engineering with specific enrichment of encapsulated species and high resolution C-13 and H-1 NMR spectroscopy with the observation of characteristic diamagnetic and paramagnetic shifts of the NMR lines and the appearance of sp(3) carbon resonances. We estimate that approximately 78% of the C-60 molecules inside SWNTs are hydrogenated to an average degree of 14 hydrogen atoms per C-60 molecule. As a consequence, the rotational dynamics of the encapsulated C60Hx molecules is clearly hindered. Our successful hydrogenation experiments open completely new roads to understand and control confined chemical reactions at the nano scale
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| 19. |
- Abou-Hamad, Edy, et al.
(författare)
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Molecular dynamics and phase transition in one-dimensional crystal of C60 encapsulated inside single wall carbon nanotubes
- 2009
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Ingår i: ACS Nano. - Washington, DC 20036 USA : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 3:12, s. 3878-3883
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Tidskriftsartikel (refereegranskat)abstract
- One-dimensional crystals of 25% 13C-enriched C60 encapsulated inside highly magnetically purified SWNTs were investigated by following the temperature dependence of the 13C NMR line shapes and the relaxation rates from 300 K down to 5 K. High-resolution MAS techniques reveal that 32% of the encapsulated molecules, so-called the C60α, are blocked at room temperature and 68%, labeled C60β, are shown to reversly undergo molecular reorientational dynamics. Contrary to previous NMR studies, spin−lattice relaxation time reveals a phase transition at 100 K associated with the changes in the nature of the C60β dynamics. Above the transition, the C60β exhibits continuous rotational diffusion; below the transition, C60β executes uniaxial hindered rotations most likely along the nanotubes axis and freeze out below 25 K. The associated activation energies of these two dynamical regimes are measured to be 6 times lower than in fcc-C60, suggesting a quiet smooth orientational dependence of the interaction between C60β molecules and the inner surface of the nanotubes.
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| 20. |
- Abrahamsson, Jonas, 1954, et al.
(författare)
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Improved outcome after relapse in children with acute myeloid leukaemia.
- 2007
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Ingår i: British journal of haematology. - : Wiley. - 0007-1048 .- 1365-2141. ; 136:2, s. 229-236
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Tidskriftsartikel (refereegranskat)abstract
- In the Nordic Society for Paediatric Haematology and Oncology paediatric study acute myeloid leukaemia (AML) 93, event-free survival was 50% and overall survival was 66%, indicating that many patients were cured following relapse. Factors influencing outcome in children with relapsed AML were investigated. The study included all 146 children in the Nordic countries diagnosed with AML between 1988 and 2003, who relapsed. Data on disease characteristics and relapse treatment were related to outcome. Sixty-six percentage achieved remission with survival after relapse (5 years) 34 +/- 4%. Of 122 patients who received re-induction therapy, 77% entered remission with 40 +/- 5% survival. Remission rates were similar for different re-induction regimens but fludarabine, cytarabine, granulocyte colony-stimulating factor-based therapy had low treatment-related mortality. Prognostic factors for survival were duration of first complete remission (CR1) and stem cell transplantation (SCT) in CR1. In early relapse (<1 year in CR1), survival was 21 +/- 5% compared with 48 +/- 6% in late relapse. For children receiving re-induction therapy, survival in early relapse was 29 +/- 6% and 51 +/- 6% in late. Patients treated in CR1 with SCT, autologous SCT or chemotherapy had a survival of 18 +/- 9, 5 +/- 5 and 41 +/- 5%, respectively. Survival was 62 +/- 6% in 64 children given SCT as part of their relapse therapy. A significant proportion of children with relapsed AML can be cured, even those with early relapse. Children who receive re-induction therapy, enter remission and proceed to SCT can achieve a cure rate of 60%.
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