| 1. |
- Rasmussen, Rasmus V, et al.
(författare)
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One-year mortality in coagulase-negative Staphylococcus and Staphylococcus aureus infective endocarditis.
- 2009
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Ingår i: Scandinavian journal of infectious diseases. - : Informa UK Limited. - 1651-1980 .- 0036-5548. ; 41:6-7, s. 456-61
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate in-hospital mortality and 12-month mortality in patients with coagulase-negative Staphylococcus (CoNS) compared to Staphylococcus aureus (S. aureus) infective endocarditis (IE). We used a prospective cohort study of 66 consecutive CoNS and 170 S. aureus IE patients, collected at 2 tertiary university hospitals in Copenhagen (Denmark) and at 1 tertiary university hospital in Gothenburg (Sweden). Median (range) C-reactive protein at admission was higher in patients with S. aureus IE (150 mg/l (1-521) vs 94 mg/l (6-303); p<0.001), which may suggest a more serous infection. CoNS was associated with prosthetic valve IE (49% vs 24%; p<0.001) and median diagnostic delay was longer in CoNS IE patients (20 d (0-232) vs 9 d (0-132); p<0.001). In-hospital mortality was equally high in both groups but 25% of the CoNS IE patients had died after 1 y compared to 39% of patients with S. aureus IE (p =0.05). In conclusion, CoNS IE was associated with a long diagnostic delay and high in-hospital mortality, whereas post-discharge prognosis was better in this group of patients compared to patients with IE due to S. aureus.
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| 2. |
- Abrahamsson, Maria, et al.
(författare)
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Steric influence on the excited-state lifetimes of ruthenium complexes with bipyridyl-alkanylene-pyridyl ligands.
- 2008
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Ingår i: Inorganic Chemistry. - : ACS. - 0020-1669 .- 1520-510X. ; 47:9, s. 3540-3548
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Tidskriftsartikel (refereegranskat)abstract
- The structural effect on the metal-to-ligand charge transfer (MLCT) excited-state lifetime has been investigated in bis-tridentate Ru(II)-polypyridyl complexes based on the terpyridine-like ligands [6-(2,2'-bipyridyl)](2-pyridyl)methane (1) and 2-[6-(2,2'-bipyridyl)]-2-(2-pyridyl)propane (2). A homoleptic ([Ru(2)(2)](2+)) and a heteroleptic complex ([Ru(ttpy)(2)](2+)) based on the new ligand 2 have been prepared and their photophysical and structural properties studied experimentally and theoretically and compared to the results for the previously reported [Ru(1)(2)](2+). The excited-state lifetime of the homoleptic Ru-II complex with the isopropylene-bridged ligand 2 was found to be 50 times shorter than that of the corresponding homoleptic Ru-II complex of ligand 1, containing a methylene bridge. A comparison of the ground-state geometries of the two homoleptic complexes shows that steric interactions involving the isopropylene bridges make the coordination to the central Ru-II ion less octahedral in [Ru(2)(2)](2+) than in [Ru(1)(2))(2+). Calculations indicate that the structural differences in these complexes influence their ligand field splittings as well as the relative stabilities of the triplet metal-to-ligand charge transfer ((MLCT)-M-3) and metal-centered ((MC)-M-3) excited states. The large difference in measured excited-state lifetimes for the two homoleptic Ru-II complexes is attributed to a strong influence of steric interactions on the ligand field strength, which in turn affects the activation barriers for thermal conversion from (MLCT)-M-3 states to short-lived (MC)-M-3 states.
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| 3. |
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| 4. |
- Bergenfelz, Anders, et al.
(författare)
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Impact of modern techniques on short-term outcome after surgery for primary hyperparathyroidism: a multicenter study comprising 2,708 patients.
- 2009
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Ingår i: Langenbeck's archives of surgery / Deutsche Gesellschaft für Chirurgie. - : Springer Science and Business Media LLC. - 1435-2451 .- 1435-2443. ; 394:5, s. 851-60
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Tidskriftsartikel (refereegranskat)abstract
- Preoperative localization procedures and the use of intraoperative parathyroidism (iOPTH) have led to a shift of paradigm from bilateral neck exploration to focused parathyroidectomy in primary hyperparathyroidism (pHPT). However, only a small number of randomized trials from specialized centers have been published. The main purpose of the study was to analyze the impact of localization procedures and iOPTH on short-term outcome after pHPT surgery in a multi-institutional setting.
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| 5. |
- Brännström, Fredrik, 1974, et al.
(författare)
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A general structure for rate-compatible concatenated codes
- 2007
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Ingår i: IEEE Communications Letters. - 1558-2558 .- 1089-7798. ; 11:5, s. 437-439
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Tidskriftsartikel (refereegranskat)abstract
- In this letter, a general concatenated code structure is presented, encompassing both parallel and serially concatenated codes as special cases. The structure provides a unifying framework for the analysis of concatenated codes and offers new degrees of freedom for code design. Performance analysis based on error bounds in the error floor region and suggestions for suitable design criteria are provided, together with a design approach for the waterfall region. The proposed structure allows for constructing very high-rate codes with no penalty in the error floor region and good performance in the waterfall region.
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| 6. |
- Brännström, Fredrik, 1974, et al.
(författare)
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Analysis and Design of Concatenated Codes
- 2006
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Ingår i: NEWCOM-ACoRN Joint Workshop, Vienna, Austria, Sept. 2006.
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Konferensbidrag (refereegranskat)abstract
- A new general concatenated code structure, containing bothparallel and serially concatenated codes as special cases, ispresented. The structure provides a unified framework forthe analysis of concatenated codes and offers new degreesof freedom for code design. Performance analysis based onbounds on the error probability in the error floor region andsuggestions for suitable design criteria are provided, togetherwith a design approach for the waterfall region. In contrast toparallel concatenated codes and traditional serially concatenatedcodes, the proposed structure allows for constructingvery high-rate codes with no penalty in the error floor regionand good performance in the waterfall region.
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| 7. |
- Brännström, Fredrik, 1974, et al.
(författare)
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Classification of 8PSK mappings for BICM
- 2007
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Ingår i: IEEE International Symposium on Information Theory. ; , s. 2136-2140, s. 2136-2140
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Konferensbidrag (refereegranskat)abstract
- The performance of bit-interleaved coded modulation with iterative decoding is significantly influenced by the mapping of bits to the symbol constellation. A range of mappers have been suggested in the literature, however, no attempt has been made to systematically enumerate all unique mappers for a given signal constellation. In this paper, we classify 8PSK mappers based on bit-wise distance spectra for no prior information, and full prior information, respectively.
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| 8. |
- Brännström, Fredrik, 1974, et al.
(författare)
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Classification of Unique Mappings for 8PSK Based on Bit-Wise Distance Spectra
- 2009
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448 .- 1557-9654. ; 55:3, s. 1131-1145
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Tidskriftsartikel (refereegranskat)abstract
- The performance of bit-interleaved coded modulation (BICM) with (or without) iterative decoding (ID) is significantly influenced by the mapping of bits to the symbol constellation. Our main objective in this paper is to develop a systematic design approach for BICM-ID schemes, ensuring the best possible performance with iterative decoding. Although useful mappings for BICM-ID have been found based on various search strategies, no attempt has been made to systematically enumerate and classify all unique mappers for a given constellation. As the basis for a systematic enumeration and classification, we define the average bit-wise distance spectrum for a mapping from bits to symbols. Different bit-wise distance spectra are derived assuming no prior information or full prior information, respectively. The bit-wise distance spectra determine corresponding bit-wise error probability and bit-wise mutual information. The latter allows us to use the classification of mappings with unique bit-wise distance spectra to also classify mappings with unique extremal points in the corresponding extrinsic information transfer (EXIT) curves. As an example of our approach, we classify 8PSK mappings into 86 classes of unique mappings according to bit-wise distance spectra. The classification can be used to significantly reduce the complexity of the search for suitable mappers for BICM-ID. For 8PSK and a given encoder, only 86 different mappings need to be, investigated. As examples of the systematic design approach, the best 8PSK mappings for minimizing the convergence threshold are found for concatenation with the rate 1/2 (5, 7)(8) and (133, 171)(8) convolutional codes, and the rate 1/2 UMTS turbo code with identical constituent convolutional codes (15/13)(8).
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| 9. |
- Brännström, Fredrik, 1974, et al.
(författare)
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Convergence analysis and optimal scheduling for multiple concatenated codes
- 2005
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448 .- 1557-9654. ; 51:9, s. 3354-3364
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Tidskriftsartikel (refereegranskat)abstract
- An interesting practical consideration for decoding of serial or parallel concatenated codes with more than two components is the determination of the lowest complexity component decoder schedule which results in convergence. This correspondence presents an algorithm that finds such an optimal decoder schedule. A technique is also given for combining and projecting a series of three-dimensional extrinsic information transfer (EXIT) functions onto a single two-dimensional EXIT chart. This is a useful technique for visualizing the convergence threshold for multiple concatenated codes and provides a design tool for concatenated codes with more than two components.
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| 10. |
- Brännström, Fredrik, 1974, et al.
(författare)
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Multiple parallel concatenated codes with optimal puncturing and energy distribution
- 2005
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Ingår i: IEEE International Conference on Communications. - 0780389387 ; , s. 622-626, s. 622–-626
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Konferensbidrag (refereegranskat)abstract
- In this paper we show how to find optimal energy distribution together with optimalpuncturing ratios for parallel concatenated codes with two or more constituent codes. The energy distribution and the puncturing ratios are optimal in terms of minimizing the average signal-to-noise ratio convergence threshold. The extrinsic information transfer functions of the constituent codes are used for the optimization. Using this technique we obtain additional degrees of freedom for constructing codes with low convergence thresholds over a large range of code rates.
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