| 1. |
- Panaccione, G., et al.
(författare)
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Coherent peaks and minimal probing depth in photoemission spectroscopy of Mott-Hubbard systems
- 2006
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 97:11
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Tidskriftsartikel (refereegranskat)abstract
- We have measured hard x-ray photoemission spectra of pure vanadium sesquioxide (V2O3) across its metal-insulator transition. We show that, in the metallic phase, a clear correlation exists between the shakedown satellites observed in the vanadium 2p and 3p core-level spectra and the coherent peak measured at the Fermi level. Comparing experimental results and dynamical mean-field theory calculations, we estimate the Hubbard energy U in V2O3 (4.20 +/- 0.05 eV). From our bulk-sensitive photoemission spectra we infer the existence of a critical probing depth for investigating electronic properties in strongly correlated solids.
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| 2. |
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| 3. |
- Secin, Fernando P, et al.
(författare)
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Multi-institutional Study of Symptomatic Deep Venous Thrombosis and Pulmonary Embolism in Prostate Cancer Patients Undergoing Laparoscopic or Robot-Assisted Laparoscopic Radical Prostatectomy
- 2008
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Ingår i: European Urology. - : Elsevier BV. - 1873-7560 .- 0302-2838. ; 53:1, s. 134-145
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The true incidence of symptomatic deep venous thrombosis (DVT) and pulmonary embolism (PE) in patients undergoing laparoscopic radical prostatectomy is unknown. Our aim was to determine the incidence of symptomatic DVT and PE and the risk factors for these complications. METHODS: Fourteen surgeons from 13 referral institutions from both Europe and the United States provided retrospective data for all 5951 patients treated with laparoscopic radical prostatectomy (LRP), with or without robotic assistance, since the start of their institution's experience. Symptomatic DVT and PE within 90 d of surgery were regarded as venous thromboembolism (VTE). DVT was diagnosed mostly by Doppler ultrasound or contrast venography and PE by lung ventilation/perfusion scan or chest computed tomography or both. Statistical analysis included evaluation of incidence of symptomatic DVT and PE and risk factors as determined by exact methods and logistic regression. RESULTS: Of 5951 patients in the study, 31 developed symptomatic VTE (0.5%; 95% confidence interval [CI], 0.4%, 0.7%). Among patients with an event, 22 (71%) had DVT only, 4 had PE without identified DVT, and 5 had both. Two patients died of PE. Prior DVT (odds ratio [OR]=13.5; 95%CI, 1.4, 61.3), current tobacco smoking (OR=2.8; 95%CI, 1.0, 7.3), larger prostate volume (OR=1.18; 95%CI, 1.09, 1.28), patient re-exploration (OR=20.6; 95%CI, 6.6, 54.0), longer operative time (OR=1.05; 95%CI, 1.02, 1.09), and longer hospital stay (OR=1.05; 95%CI, 1.01, 1.09) were associated with VTE in univariate analysis. Neoadjuvant therapy, body mass index, surgical experience, surgical approach, pathologic stage, perioperative transfusion, and heparin administration were not significant predictors. CONCLUSIONS: The incidence of symptomatic VTE after LRP is low. These data do not support the administration of prophylactic heparin to all patients undergoing LRP, especially those without risk factors for VTE.
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| 4. |
- Baghaei Nejad, Majid, et al.
(författare)
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Impulse UWB Antenna size reduction due to Transmitter-Antenna Co-design
- 2008
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Ingår i: 2008 IEEE INTERNATIONAL CONFERENCE ON ULTRA-WIDEBAND. - New York : IEEE. - 9781424422166 ; , s. 37-40
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Konferensbidrag (refereegranskat)abstract
- In this paper, the benefit of a co-design between a modified small-size Printed Tapered Monopole Antenna (PTMA) and an Impulse Ultra Wideband transmitter Is Investigated for the 3.1-10.6GHz bond. A comparison is given between a 50 Omega design and a co-designed version. The simulation results show that with the co-design method the tunable UWB transmitter can reach the bandwidth regulation for a much smaller antenna.
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| 5. |
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| 6. |
- Massey, Philip, et al.
(författare)
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RED SUPERGIANTS IN THE ANDROMEDA GALAXY (M31)
- 2009
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 703:1, s. 420-440
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Tidskriftsartikel (refereegranskat)abstract
- Red supergiants (RSGs) are a short-lived stage in the evolution of moderately massive stars (10-25 M-circle dot), and as such their location in the H-R diagram provides an exacting test of stellar evolutionary models. Since massive star evolution is strongly affected by the amount of mass loss a star suffers, and since the mass-loss rates depend upon metallicity, it is highly desirable to study the physical properties of these stars in galaxies of various metallicities. Here we identify a sample of RSGs in M31, the most metal-rich of the Local Group galaxies. We determine the physical properties of these stars using both moderate resolution spectroscopy and broadband V-K photometry. We find that on average the RSGs of our sample are variable in V by 0.5 mag, smaller but comparable to the 0.9 mag found for Magellanic Cloud (MC) RSGs. No such variability is seen at K, also in accord with what we know of Galactic and MC RSGs. We find that there is a saturation effect in the model TiO band strengths with metallicities higher than solar. The physical properties we derive for the RSGs from our analysis with stellar atmosphere models agree well with the current evolutionary tracks, a truly remarkable achievement given the complex physics involved in each. We do not confirm an earlier result that the upper luminosities of RSGs depend upon metallicity; instead, the most luminous RSGs have log L/L-circle dot similar to 5.2-5.3, broadly consistent but slightly larger than that recently observed by Smartt et al. as the upper luminosity limit to Type II-P supernovae, believed to have come from RSGs. We find that, on average, the RSGs are considerably more reddened than O and B stars, suggesting that circumstellar dust is adding a significant amount of extra extinction, similar to 0.5 mag, on average. This is in accord with our earlier findings on Milky Way and Magellanic Cloud stars. Finally, we call attention to a peculiar star whose spectrum appears to be heavily veiled, possibly due to scattering by an expanding dust shell.
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| 7. |
- Radiom, Soheil, et al.
(författare)
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Antenna Miniaturization Influence on the Performance of Impulse Radio UWB system
- 2008
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Ingår i: Proceedings of the 1st European Wireless Technology Conference, EuWiT 2008. - NEW YORK : IEEE. - 9781424437931 ; , s. 362-365
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper the effect of antenna miniaturization in a UWB system is presented. Modified small-size printed tapered monopole antennas are designed in different scaling sizes. In order to evaluate the antennas performance and their functionality, the performance of three kinds of UWB systems, Correlation Detection, Energy Detection and Transmitted Reference UWB, is studied in the presence of each antenna in the AWGN channel. The simulation results show that our designed antenna and its miniaturized geometries are suitable for UWB applications.
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| 8. |
- Strömstedt, Adam A, 1977-
(författare)
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Antimicrobial Peptide Interactions with Phospholipid Membranes : Effects of Peptide and Lipid Composition on Membrane Adsorption and Disruption
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The interactions between antimicrobial peptides and phospholipid membranes were investigated, in terms of lipid headgroup variations and the role of cholesterol, as well as peptide composition and structure. Also strategies for increasing proteolytic stability were evaluated. The interactions were studied on model membranes in the form of liposomes and supported bilayers, through a combination of ellipsometry, fluorescence spectroscopy, circular dichroism, dynamic light scattering, electrophoresis, electron cryomicroscopy, and bacterial/cell culture experiments. The findings showed that membrane tolerance against the lytic activity of melittin, was increased on anionic membranes by electrostatic arrest in the headgroup region, and was reduced by hydration repulsion. The presence of cholesterol caused a reduction in melittin adsorption, while at the same time reducing membrane tolerance per adsorbed peptide. Differences in membrane leakage mechanisms were also attributed to cholesterol, where large scale structural effects contributed to the leakage, while other membranes followed the pore formation model. Substituting specific amino acids for tryptophan on an LL-37 derivative, was shown to increase stability against bacterial proteases, while at the same time significantly increasing antibacterial properties. These substitutions, as well as terminal modifications, increased adsorption and membrane lytic properties in a way that was less dependent on electrostatics. Furthermore, by comparing short cationic peptides with oligotryptophan end-tagged versions, the lytic mechanism of end-tagged peptides, and the different contributions of arginine and lysine to membrane adsorption and disruption were demonstrated. This thesis is a contribution to the development of antimicrobial peptides as therapeutic alternatives to conventional antibiotics.
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