| 1. |
- Acciari, V. A., et al.
(författare)
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Radio Imaging of the Very-High-Energy gamma-Ray Emission Region in the Central Engine of a Radio Galaxy
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 325:5939, s. 444-448
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Tidskriftsartikel (refereegranskat)abstract
- The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 10(12) electron volts and are bright sources of very-high-energy (VHE) gamma-ray emission, it is not yet known where the VHE emission originates. Here we report on radio and VHE observations of the radio galaxy Messier 87, revealing a period of extremely strong VHE gamma-ray flares accompanied by a strong increase of the radio flux from its nucleus. These results imply that charged particles are accelerated to very high energies in the immediate vicinity of the black hole.
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| 2. |
- Rosengren, Annika, 1951, et al.
(författare)
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Education and risk for acute myocardial infarction in 52 high, middle and low-income countries: INTERHEART case-control study
- 2009
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Ingår i: Heart. - 1468-201X. ; 95:24, s. 2014-22
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To determine the effect of education and other measures of socioeconomic status (SES) on risk of acute myocardial infarction (AMI) in patients and controls from countries with diverse economic circumstances (high, middle, and low income countries). DESIGN: Case-control study. SETTING: 52 countries from all inhabited regions of the world. PARTICIPANTS: 12242 cases and 14622 controls. MAIN OUTCOME MEASURES: First non-fatal AMI. RESULTS: SES was measured using education, family income, possessions in the household and occupation. Low levels of education (< or =8 years) were more common in cases compared to controls (45.0% and 38.1%; p<0.0001). The odds ratio (OR) for low education adjusted for age, sex and region was 1.56 (95% confidence interval 1.47 to 1.66). After further adjustment for psychosocial, lifestyle, other factors and mutually for other socioeconomic factors, the OR associated with education < or =8 years was 1.31 (1.20 to 1.44) (p<0.0001). Modifiable lifestyle factors (smoking, exercise, consumption of vegetables and fruits, alcohol and abdominal obesity) explained about half of the socioeconomic gradient. Family income, numbers of possessions and non-professional occupation were only weakly or not at all independently related to AMI. In high-income countries (World Bank Classification), the risk factor adjusted OR associated with low education was 1.61 (1.33 to 1.94), whereas it was substantially lower in low-income and middle-income countries: 1.25 (1.14 to 1.37) (p for interaction 0.045). CONCLUSION: Of the SES measures we studied, low education was the marker most consistently associated with increased risk for AMI globally, most markedly in high-income countries.
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| 3. |
- Aryal, M. M., et al.
(författare)
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Understanding of nuclear quadrupole interactions of Cl-35, Br-79 and I-129 and binding energies of solid halogens at first-principles level
- 2007
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Ingår i: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540. ; 176:1-3, s. 51-57
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with the understanding at a first-principles level of the nuclear quadrupole interaction (NQI) parameters of solid chlorine, bromine and iodine as well as the intermolecular binding of these molecules in the solid. The electronic structure investigations that we have carried out to study these properties of the solid halogens are based on the Hartree-Fock Cluster approach using the Roothaan variational procedure with electron correlation effects included using many-body perturbation theory with the empty orbitals used in the perturbation theory investigations for the excited states. The results of our investigations provide good agreement with the measured NQI parameters primarily from the Hartree-Fock one electron wave-functions with many-body effects making minor contributions. The binding (dissociation) energies for the molecules with the solid state environment on the other hand arises from intermolecular many body effects identified as the Van der Waals attraction with one-electron Hartree-Fock contribution being repulsive in nature.
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| 4. |
- Chow, J.M., et al.
(författare)
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Randomized benchmarking and process tomography for gate errors in a solid-state qubit
- 2009
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 102:9
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of single-qubit gate errors for a superconducting qubit. Results from quantum process tomography and randomized benchmarking are compared with gate errors obtained from a double pulse experiment. Randomized benchmarking reveals a minimum average gate error of 1.1±0.3% and a simple exponential dependence of fidelity on the number of gates. It shows that the limits on gate fidelity are primarily imposed by qubit decoherence, in agreement with theory.
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| 5. |
- Sodergren, Erica, et al.
(författare)
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The genome of the sea urchin Strongylocentrotus purpuratus.
- 2006
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 314:5801, s. 941-52
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Tidskriftsartikel (refereegranskat)abstract
- We report the sequence and analysis of the 814-megabase genome of the sea urchin Strongylocentrotus purpuratus, a model for developmental and systems biology. The sequencing strategy combined whole-genome shotgun and bacterial artificial chromosome (BAC) sequences. This use of BAC clones, aided by a pooling strategy, overcame difficulties associated with high heterozygosity of the genome. The genome encodes about 23,300 genes, including many previously thought to be vertebrate innovations or known only outside the deuterostomes. This echinoderm genome provides an evolutionary outgroup for the chordates and yields insights into the evolution of deuterostomes.
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| 6. |
- Buyanova, Irina, 1960-, et al.
(författare)
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Optical characterization of ZnMnO-based dilute magnetic semiconductor structures
- 2006
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Ingår i: Journal of Vacuum Science & Technology B. - : American Vacuum Society. - 1071-1023 .- 1520-8567. ; 24:1, s. 259-262
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Tidskriftsartikel (refereegranskat)abstract
- n -type ZnMnO spin injection layers were grown by pulsed laser deposition on top of n-ZnMgOZnOp-AlGaNp-GaN hybrid spin light-emitting diode (LED) structures synthesized by molecular-beam epitaxy. Both the ZnMnOZnMgOZnOAlGaNGaN structures and control ZnMnO samples show no or very low (up to 10% at the lowest temperatures) optical (spin) polarization at zero field or 5 T, respectively. This indicates difficulties in generating spin polarization by optical spin orientation or possible efficient spin losses. The results are similar to those found earlier for GaMnNInGaNAlGaN spin-LED structures and indicate that these wide-band-gap dilute magnetic semiconductors with weak spin-orbit interaction and hexagonal symmetry are not attractive for spin-LED applications. © 2006 American Vacuum Society.
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| 7. |
- Dubey, Archana, et al.
(författare)
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Nuclear quadrupole interactions and electronic structure of BF3 center dot H2O complex
- 2007
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Ingår i: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540. ; 176:1-3, s. 45-50
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Tidskriftsartikel (refereegranskat)abstract
- This work deals with first-principles investigation of the electronic structure of the BF3 center dot H2O complex which is important in catalysis of organic reactions and polymerization. The dissociation energy of the BF3 center dot H2O complex and the nuclear quadrupole interaction parameters for the excited nuclear state F-19* (I = 5/2) of the fluorine nuclei have been studied. Our investigation shows that the complexation bond BO between the BF3 and H2O units is strongly influenced by the larger electronegativity of Oxygen as compared to Nitrogen in BF3 center dot NH3. The quadrupole coupling constants of F-19* and the asymmetry parameter are however quite close to those for BF3 center dot NH3. The likely reasons for these features of these two important catalytic systems are suggested.
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| 8. |
- Hägerlöf, Margareta, et al.
(författare)
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More pronounced salt dependence and higher reactivity for platination of the hairpin r(CGCGUUGUUCGCG) compared with d(CGCGTTGTTCGCG)
- 2006
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Ingår i: Journal of Biological Inorganic Chemistry. - : Springer Science and Business Media LLC. - 1432-1327 .- 0949-8257. ; 11:8, s. 974-990
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Tidskriftsartikel (refereegranskat)abstract
- The DNA interference pathways exhibited by cisplatin and related anticancer active metal complexes have been extensively studied. Much less is known to what extent RNA interaction pathways may operate in parallel, and perhaps contribute to both antineoplastic activity and toxicity. The present study was designed with the aim of comparing the reactivity of two model systems comprising RNA and DNA hairpins, r(CGCGUUGUUCGCG) and d(CGC GTTGTTCGCG), towards a series of platinum(II) complexes. Three platinum complexes were used as metallation reagents; cis-[ptCl(NH3)(2)(OH2)](+) (1), cis-[PtCl(NH3)(C-C6H11NH2)(OH2)](+) (2), and trans[PtCl(NH3)(quinoline)(OH2)](+) (3). The reaction kinetics were studied at pH 6.0, 25 degrees C, and 1.0 mM < 1: 500 mM. For both types of nucleic acid targets, compound 3 was found to react about 1 order of magnitude more rapidly than compounds 1 and 2. Further, all platinum compounds exhibited a more pronounced salt dependence for the interaction with r(CGCGUUGUUCGCG). Chemical and enzymatic cleavage studies revealed similar interaction patterns with r(CGCGUUGUUCGCG) after long exposure times to 1 and 2. A substantial decrease of cleavage intensity was found at residues G4 and G7, indicative of bifunctional adduct formation. Circular dichroism studies showed that platinum adduct formation leads to a structural change of the ribonucleic acid. Thermal denaturation studies revealed platination to cause a decrease of the RNA melting temperatures by 5-10 degrees C. Our observations therefore suggest that RNA is a kinetically competitive target to DNA. Furthermore, platination causes destabilization of RNA structural elements, which may lead to deleterious intracellular effects on biologically relevant RNA targets.
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| 9. |
- Lata, K. Ramani, et al.
(författare)
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Investigation of the hyperfine properties of deoxy hemoglobin based on its electronic structure obtained by Hartree-Fock-Roothan procedure
- 2008
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Ingår i: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540. ; 181:1-3, s. 75-80
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of the heme unit of deoxyhemoglobin including the proximal imidazole has been studied using the first-principles Hartree-Fock procedure. Our results for the Fe-57m isomer shift and asymmetry parameter are in very good agreement with the values obtained from Mossbauer spectroscopy measurements. The Fe-57m nuclear quadrupole coupling constant is smaller than the experimental result and possible ways to improve the agreement in the future are discussed. Improved analysis of the Mossbauer data, removing some approximations made for deriving the magnetic hyperfine tensor for the Fe-57m nucleus, is suggested to allow quantitative comparison with our results in the future.
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| 10. |
- Mahato, Dip N., et al.
(författare)
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First principles study of nuclear quadrupole interactions in the molecular solid BF3 and the nature of binding between the molecules
- 2007
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Ingår i: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540. ; 176:1-3, s. 15-20
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structures and nuclear quadrupole interactions (NQI) of the F-19* (I= 5/2) state of F-19 nucleus in solid BF3 are studied using the first-principles Hartree-Fock-Roothaan procedure including many-body electron correlation effects. The calculated NQI parameters, F-19* quadrupole coupling constant (e(2)qQ) and asymmetry parameter eta, were found to be in satisfactory agreement with experiment for the solid state system, which gives confidence in the reliability of the calculated electronic structures in the solid and hence the factors found to influence the binding of the molecules in the solid. It was found that the intermolecular binding energy primarily arises from Van der Waals (VDW) interactions between the molecules resulting from intermolecular many-body effects, which counteract the repulsive interactions between the molecules arising from one-electron Hartree-Fock (HF) theory.
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| 11. |
- Mahato, Dip N., et al.
(författare)
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Theoretical investigation of nuclear quadrupole interactions in DNA at first-principles level
- 2008
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Ingår i: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540. ; 181:1-3, s. 81-86
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the nuclear quadrupole interactions (NQI) of the N-14, O-17 and H-2 nuclei in the nucleobases cytosine, adenine, guanine and thymine in the free state as well as when they are bonded to the sugar ring in DNA, simulated through a CH3 group attached to the nucleobases. The nucleobase uracil, which replaces thymine in RNA, has also been studied. Our results show that there are substantial indirect effects of the bonding with the sugar group in the nucleic acids on the NQI parameters e(2)qQ/h and eta. It is hoped that measurements of these NQI parameters in DNA will be available in the future to compare with our predictions. Our results provide the conclusion that for any property dependent on the electronic structures of the nucleic acids, the effects of the bonding between the nucleobases and the nucleic acid backbones have to be included.
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| 12. |
- Pink, R. H., et al.
(författare)
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Theory of electronic structure and nuclear quadrupole interactions in the BF3-NH3 complex and methyl derivatives
- 2007
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Ingår i: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540. ; 176:1-3, s. 39-44
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Tidskriftsartikel (refereegranskat)abstract
- Magnetic Hyperfine and Nuclear Quadrupole Interactions (HFI and NQI) are now important tools for characterization of systems of interest in materials research and industry. Boron-Trifluoride is an inorganic compound that is very important in this respect as a catalyst in chemical physics research and industry, forming complexes in the process with compounds like ammonia, water and methyl alcohol. The present paper deals with the BF3-NH3 complex and methyl derivatives BF3NHx(CH3)(3-x) for which we have studied the electronic structures, binding energies, and F-19* (I=5/2) nuclear quadrupole interactions using the first-principles Hartree-Fock-Roothaan procedure combined with electron correlation effects. Our results for the F-19* nuclear quadrupole coupling constant (e(2)qQ/h) in units of MHz compare well with experiment. Trends in the binding energies and NQI parameters between the complexes are discussed.
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| 13. |
- Seggewiss, R, et al.
(författare)
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Keratinocyte growth factor augments immune reconstitution after autologous hematopoietic progenitor cell transplantation in rhesus macaques
- 2007
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 110:1, s. 441-449
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Tidskriftsartikel (refereegranskat)abstract
- Opportunistic infections contribute to morbidity and mortality after peripheral blood progenitor cell (PBPC) transplantation and are related to a deficient T-cell compartment. Accelerated T-cell reconstitution may therefore be clinically beneficent. Keratinocyte growth factor (KGF) has been shown to protect thymic epithelial cells in mice. Here, we evaluated immune reconstitution after autologous CD34+ PBPC transplantation in rhesus macaques conditioned with myeloablative total body irradiation in the absence or presence of single pretotal body irradiation or repeated peritransplant KGF administration. All KGF-treated animals exhibited a well-preserved thymic architecture 12 months after graft. In contrast, thymic atrophy was observed in the majority of animals in the control group. The KGF-treated animals showed higher frequencies of naive T cells in lymph nodes after transplantation compared with the control animals. The animals given repeated doses of KGF showed the highest levels of T-cell receptor excision circles (TRECs) and the lowest frequencies of Ki67+ T cells, which suggest increased thymic-dependent reconstitution in these animals. Of note, the humoral response to a T-cell–dependent neo-antigen was significantly higher in the KGF-treated animals compared with the control animals. Thus, our findings suggest that KGF may be a useful adjuvant therapy to augment T-cell reconstitution after human PBPC transplantation.
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| 14. |
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