| 1. |
- Bergquist, Maria, et al.
(författare)
-
Expression of the glucocorticoid receptor is decreased in experimental Staphylococcus aureus sepsis
- 2013
-
Ingår i: Journal of Infection. - : Elsevier BV. - 0163-4453 .- 1532-2742. ; 67:6, s. 574-583
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Glucocorticoid treatment in septic shock remains controversial after recent trials. We hypothesized that failure to respond to steroid therapy may be caused by decreased expression and/or function of glucocorticoid receptors (GR) and studied this in a mouse model of Staphylococcus aureus sepsis. The impact of timing of dexamethasone treatment was also investigated. Methods: Male C57BL/6J mice were intravenously inoculated with S. aureus and GR expression and binding ability in blood, spleen and lymph nodes were analysed by means of flow cytometry. GR translocation was analysed using Image Stream. Septic mice were administered dexamethasone at 22, 26, 48, 72 and 96 h after inoculation and body weight, as a sign of dehydration, was observed. Results: GR expression was decreased in septic animals, but not the ligand binding capacity. GR translocation was decreased in septic mice compared to control animals. Early dexamethasone treatment (22 and 26 h) improved clinical outcome as studied by weight gain compared to when treatment was started at later time points (48, 72 and 96 h). Conclusion: Our data provide evidence that GR expression is progressively decreased in experimental sepsis and that dexamethasone has a decreased ability to translocate into the cell nucleus. This may explain why steroid treatment is only beneficial when administered early in sepsis and septic shock.
|
|
| 2. |
- Winges, Johan, 1987, et al.
(författare)
-
Multi-objective optimization of wireless power transfer systems with magnetically coupled resonators and nonlinear loads
- 2019
-
Ingår i: Progress in Electromagnetics Research B. - 1937-6472. ; 83:2019, s. 25-42
-
Tidskriftsartikel (refereegranskat)abstract
- © 2019 Progress In Electromagnetics Research B. We present an optimization procedure for wireless power transfer (WPT) applications and test it numerically for a WPT system design with four resonant circuits that are magnetically coupled by coaxial coils in air, where the magnetic field problem is represented by a fully populated inductance matrix that includes all magnetic interactions that occur between the coils. The magnetically coupled resonators are fed by a square-wave voltage generator and loaded by a rectifier followed by a smoothing filter and a battery. We compute Pareto fronts associated with a multi-objective optimization problem that contrasts: 1) the system efficiency; and 2) the power delivered to the battery. The optimization problem is constrained in terms of: 1) the physical construction of the system and its components; 2) the root-mean-square values of the currents and voltages in the circuit; and 3) bounds on the overtones of the currents in the coils in order assure that the WPT system mainly generates magnetic fields at the operating frequency. We present optimized results for transfer distances from 0.8 to 1.6 times the largest coil radius with a maximum power transfer from 4 kW to 9 kW at 85 kHz, which is achieved at an efficiency larger than 90%.
|
|
| 3. |
- WINGES, JOHAN, 1987, et al.
(författare)
-
System Identification and Tuning of Wireless Power Transfer Systems with Multiple Magnetically Coupled Resonators
- 2018
-
Ingår i: Transactions on Environment and Electrical Engineering. - : EEEIC International Publishing. - 2450-5730. ; 2:2, s. 86-92
-
Tidskriftsartikel (refereegranskat)abstract
- We present a procedure for system identification and tuning of a wireless power transfer (WPT) system with four magnetically coupled resonators, where each resonator consists of a coil and a capacitor bank. The system-identification procedure involves three main steps: 1) individual measurement of the capacitor banks in the system; 2) measurement of the frequency-dependent two-port impedance matrix of the magnetically coupled resonators; and 3) determining the inductance of all coils and their corresponding coupling coefficients using a Bayesian approach. The Bayesian approach involves solving an optimization problem where we minimize the mismatch between the measured and simulated impedance matrix together with a penalization term that incorporates information from a direct measurement procedure of the inductance and losses of the coils. This identification procedure yields an accurate system model which we use to tune the four capacitance values to recover high system-performance and account for, e.g., manufacturing tolerances and coil displacement. For a prototype WPT system, we achieve 3.3 kW power transfer with 91 % system efficiency over an air-gap distance of approximately 20 cm.
|
|
| 4. |
- WINGES, JOHAN, 1987, et al.
(författare)
-
System Identification and Tuning of WPT Systems
- 2017
-
Ingår i: 2017 IEEE 17th International Conference on Environment and Electrical Engineering (EEEIC).
-
Konferensbidrag (refereegranskat)abstract
- We present a procedure for system identificationand tuning of a wireless power transfer (WPT) system withfour magnetically coupled resonators, where each resonator consists of a coil and a capacitor bank. The system-identification procedure involves three main steps: 1) individual measurement of the capacitor banks in the system; 2) measurement of the frequency-dependent two-port impedance matrix of the magnetically coupled resonators; and 3) determining the inductance of all coils and their corresponding coupling coefficients using a Bayesian approach. The Bayesian approach involves solving an optimization problem where we minimize the mismatch between the measured and simulated impedance matrix together with a penalization term that incorporates information from a direct measurement procedure of the inductances and losses of the coils.This identification procedure yields an accurate system model which we use to tune the four capacitance values to recover high system-performance and account for, e.g., manufacturing tolerances and coil displacement. For a prototype WPT system, we achieve 3.3 kW power transfer with 91% system efficiency over an air-gap distance of approximately 20 cm.
|
|
