| 1. |
- Kressner, Marit, et al.
(författare)
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The impact of hospital volume on surgical outcome in patients with rectal cancer.
- 2009
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Ingår i: Diseases of the colon and rectum. - 1530-0358 .- 0012-3706. ; 52:9, s. 1542-9
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: This study was designed to investigate, in a population-based setting, the surgical outcome in patients with rectal cancer according to the hospital volume. METHODS: Since 1995 all patients with rectal cancer have been registered in the Swedish Rectal Cancer Registry. Hospitals were classified, according to number treated per year, as low-volume, intermediate-volume, or high-volume hospitals (<11, 11-25, or >25 procedures per year). Postoperative mortality, reoperation rate within 30 days, local recurrence rate, and overall five-year survival were studied. For postoperative morbidity and mortality the whole cohort from 1995 to 2003 (n = 10,425) was used. For cancer-related outcome only, those with five-year follow-ups, from 1995 to 1998, were used (n = 4,355). RESULTS: In this registry setting the postoperative mortality rate was 3.6% in low-volume hospitals, and 2.2% in intermediate-volume and high-volume hospitals (P = 0.002). The reoperation rate was 10%, with no differences according to volume. The overall local recurrence rates were 9.4%, 9.3%, and 7.5%, respectively (P = 0.06). Significant difference was found among the nonirradiated patients (P = 0.004), but not among the irradiated patients (P = 0.45). No differences were found according to volume in the absolute five-year survival. CONCLUSION: Postoperative mortality and local recurrence in nonirradiated patients were lower in high-volume hospitals. No difference was seen between volumes in reoperation rates, overall local recurrence, or absolute five-year survival.
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| 2. |
- Mowlér, Marc, et al.
(författare)
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Capacity and Gain Analysis of a Reconfigurable MEMS Antenna
- 2008
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Ingår i: Nordic Conference on Radio Science and Communications (RVK).
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents the investigation results on therecon¯gurable properties of an antenna array compris-ing of four feed elements and four parasitic elementsplaced on a ¯nite ground plane. This antenna is in-tended to improve the diversity gain for a Multiple In-put Multiple Output (MIMO) communication system.We intend to use a recon¯gurable antenna to com-bat the problem of signal deterioration in a handhelddevice so that it can get optimum signal strength inany orientation. With our presented antenna, we canachieve up to sixteen di®erent con¯gurations depend-ing on the requirement. The di®erent con¯gurationsare controlled with the help of RF switches which areimplemented using micro-electromechanical systems(MEMS). The recon¯gurable antenna was fabricatedand tested for its impedance and radiation character-istics and the results were found to be in reasonable agreement with the simulations. Channel measure-ments were made with the help of a MIMO test setup.
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| 3. |
- Mowlér, Marc, et al.
(författare)
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Joint estimation of mutual coupling, element factor, and phase center in antenna arrays
- 2007
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Ingår i: EURASIP Journal on Wireless Communications and Networking. - : Springer Science and Business Media LLC. - 1687-1472 .- 1687-1499. ; 2007:1, s. 030684-
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Tidskriftsartikel (refereegranskat)abstract
- A novel method is proposed for estimation of the mutual coupling matrix of an antenna array. The method extends previous work by incorporating an unknown phase center and the element factor (antenna radiation pattern) in the model, and treating them as nuisance parameters during the estimation of coupling. To facilitate this, a parametrization of the element factor based on a truncated Fourier series is proposed. The performance of the proposed estimator is illustrated and compared to other methods using data from simulations and measurements, respectively. The Cramer-Rao bound (CRB) for the estimation problem is derived and used to analyze how the required amount of measurement data increases when introducing additional degrees of freedom in the element factor model. We find that the penalty in SNR is 2.5 dB when introducing a model with two degrees of freedom relative to having zero degrees of freedom. Finally, the tradeoff between the number of degrees of freedom and the accuracy of the estimate is studied. A linear array is treated in more detail and the analysis provides a specific design tradeoff.
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| 4. |
- Mowlér, Marc, et al.
(författare)
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Methods and bounds for antenna array coupling matrix estimation
- 2007
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Ingår i: 2007 IEEE International Conference on Acoustics, Speech, and Signal Processing. - : IEEE. - 1424407273 - 1424407281 ; , s. 881-884
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Konferensbidrag (refereegranskat)abstract
- A novel method is proposed for estimation of the mutual coupling matrix of an antenna array. The method extends previous work by incorporating an unknown phase center and the element factor (antenna radiation pattern) in the model, and treating these as nuisance parameters during the estimation of coupling. To facilitate this, a parametrization of the element factor based on a truncated Fourier series is proposed. The Cramer-Rao bound (CRB) for the estimation problem is derived and used to analyze how the required amount of measurement data increases when introducing a more and more flexible model for the element factor. Finally, the performance of the proposed estimator is illustrated using data from measurements on an 8-element antenna array.
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| 5. |
- Mowlér, Marc, 1979-
(författare)
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On Reconfigurable MEMS Antennas and Coupling Matrix Estimation
- 2006
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, two different topics are treated related to wireless communication. Part I presents three different reconfigurable MEMS integrated antennas for MIMO applications. Simulation and measurement results are presented along with brief discussions on the topic of antenna selection with reconfigurable antenna elements. Part II presents an estimator for the coupling matrix of an antenna array with two slightly different approaches. CRB is derived and discussed in terms of parameter cost.
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| 6. |
- Mowlér, Marc, et al.
(författare)
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Switched MEMS Antenna for Handheld Devices
- 2008
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Ingår i: ICT-MobileSummit 2008.
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Konferensbidrag (refereegranskat)abstract
- This paper presents the investigation results on the reconfigurableproperties of a monopole antenna array. The antenna array comprises of four feedelements and four parasitic elements on a finite ground plane. This antenna isintended to improve the diversity gain for a Multiple Input Multiple Output (MIMO)communication system. We intend to combat the problem of signal deterioration inhandheld devices by the use of reconfigurable antenna. A common communicationproblem seen in the handheld devices is the change in strength of radio signal whenthe orientation of the device is changed. Reconfigurable antennas can be used get ridof this nuisance so that what ever be the orientation, the handheld device still gets thebest possible signal level. With our presented antenna, we can achieve up to sixteendifferent configurations depending upon the requirement. The differentconfigurations are controlled with the help of RF switches which are implementedusing micro-electromechanical systems (MEMS). The reconfigurable antenna wasfabricated and tested for its impedance and radiation characteristics and the resultswere found to be in reasonable agreement with the simulations.
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| 7. |
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| 8. |
- Becker, K., et al.
(författare)
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Antibacterial activity of apramycin at acidic pH warrants wide therapeutic window in the treatment of complicated urinary tract infections and acute pyelonephritis
- 2021
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Ingår i: EBioMedicine. - : Elsevier B.V.. - 2352-3964. ; 73
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Tidskriftsartikel (refereegranskat)abstract
- Background: The clinical-stage drug candidate EBL-1003 (apramycin) represents a distinct new subclass of aminoglycoside antibiotics for the treatment of drug-resistant infections. It has demonstrated best-in-class coverage of resistant isolates, and preclinical efficacy in lung infection models. However, preclinical evidence for its utility in other disease indications has yet to be provided. Here we studied the therapeutic potential of EBL-1003 in the treatment of complicated urinary tract infection and acute pyelonephritis (cUTI/AP). Methods: A combination of data-base mining, antimicrobial susceptibility testing, time-kill experiments, and four murine infection models was used in a comprehensive assessment of the microbiological coverage and efficacy of EBL-1003 against Gram-negative uropathogens. The pharmacokinetics and renal toxicology of EBL-1003 in rats was studied to assess the therapeutic window of EBL-1003 in the treatment of cUTI/AP. Findings: EBL-1003 demonstrated broad-spectrum activity and rapid multi-log CFU reduction against a phenotypic variety of bacterial uropathogens including aminoglycoside-resistant clinical isolates. The basicity of amines in the apramycin molecule suggested a higher increase in positive charge at urinary pH when compared to gentamicin or amikacin, resulting in sustained drug uptake and bactericidal activity, and consequently in potent efficacy in mouse infection models. Renal pharmacokinetics, biomarkers for toxicity, and kidney histopathology in adult rats all indicated a significantly lower nephrotoxicity of EBL-1003 than of gentamicin. Interpretation: This study provides preclinical proof-of-concept for the efficacy of EBL-1003 in cUTI/AP. Similar efficacy but lower nephrotoxicity of EBL-1003 in comparison to gentamicin may thus translate into a higher safety margin and a wider therapeutic window in the treatment of cUTI/API. Funding: A full list of funding bodies that contributed to this study can be found in the Acknowledgements section. © 2021 The Author(s)
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| 9. |
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| 10. |
- Beckman, Claes, 1962-, et al.
(författare)
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Base station antennas for mobile communications
- 2007
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Ingår i: 2007 IEEE International Symposium on Antennas and Propagation.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This course gives the participants a general overview of the application, implementation and design of current and future base station antennas for mobile communications. It is aimed at microwave, RF- and antenna engineers in the wireless area, but also useful for researchers looking for relevant research topics and system engineers needing a deeper understanding of the antenna component of their system. The course explains underlying theoretical and practical implementation aspects of base station antennas in mobile communication networks of today and the future. The course is divided into three main parts: (i) System Aspects, (ii) BTS Antenna Design, (iii) Diversity and MIMO In the first part the fundamental parameters of a base station antenna are discussed in the context of radio network design. In particular we discuss parameters such as gain, radiation patterns, frequency bands and power handling and put them in the context of cell planning, propagation and capacity. In the second part a general overview of base station antenna design is given. In particular the design aspects of radiators, feed networks and reflectors are discussed. Furthermore, a general discussion of array synthesis for base station antennas is given. In the final part of the course we give an overview of the underlying theory of diversity and MIMO systems. In particular we discuss the requirements that these systems put on the base station antennas in order to be able to deliver the data rates expected from WiMAX and the long term evolution of 3G systems.
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