| 1. |
- Bergemalm, Daniel, 1977-, et al.
(författare)
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Systemic Inflammation in Preclinical Ulcerative Colitis
- 2021
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Ingår i: Gastroenterology. - : AGA Institute. - 0016-5085 .- 1528-0012. ; 161:5, s. 1526-1539.e9
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Preclinical ulcerative colitis is poorly defined. We aimed to characterize the preclinical systemic inflammation in ulcerative colitis, using a comprehensive set of proteins.Methods: We obtained plasma samples biobanked from individuals who developed ulcerative colitis later in life (n = 72) and matched healthy controls (n = 140) within a population-based screening cohort. We measured 92 proteins related to inflammation using a proximity extension assay. The biologic relevance of these findings was validated in an inception cohort of patients with ulcerative colitis (n = 101) and healthy controls (n = 50). To examine the influence of genetic and environmental factors on these markers, a cohort of healthy twin siblings of patients with ulcerative colitis (n = 41) and matched healthy controls (n = 37) were explored.Results: Six proteins (MMP10, CXCL9, CCL11, SLAMF1, CXCL11 and MCP-1) were up-regulated (P < .05) in preclinical ulcerative colitis compared with controls based on both univariate and multivariable models. Ingenuity Pathway Analyses identified several potential key regulators, including interleukin-1β, tumor necrosis factor, interferon-gamma, oncostatin M, nuclear factor-κB, interleukin-6, and interleukin-4. For validation, we built a multivariable model to predict disease in the inception cohort. The model discriminated treatment-naïve patients with ulcerative colitis from controls with leave-one-out cross-validation (area under the curve = 0.92). Consistently, MMP10, CXCL9, CXCL11, and MCP-1, but not CCL11 and SLAMF1, were significantly up-regulated among the healthy twin siblings, even though their relative abundances seemed higher in incident ulcerative colitis.Conclusions: A set of inflammatory proteins are up-regulated several years before a diagnosis of ulcerative colitis. These proteins were highly predictive of an ulcerative colitis diagnosis, and some seemed to be up-regulated already at exposure to genetic and environmental risk factors.
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| 2. |
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| 3. |
- Georen, P., et al.
(författare)
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An electrochemical impedance spectroscopy method applied to porous LiMn2O4 and metal hydride battery electrodes
- 2003
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 150:2, s. A234-A241
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Tidskriftsartikel (refereegranskat)abstract
- An electrochemical impedance spectroscopy method utilizing the signals from reference electrodes positioned in front of and behind a porous electrode is investigated. The basis for the method is illustrated theoretically, and limiting values under different assumptions are presented. The method was applied to a porous metal hydride and a LiMn2O4 battery electrode. It was concluded that the method facilitates the separation of local impedance effects from the effects of the potential distribution in the porous electrode. Consequently, a more accurate determination of local kinetic parameters and the effective conductivity in the pore electrolyte could be obtained.
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| 4. |
- Hjelm, A. K., et al.
(författare)
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Investigation of LiMn2O4 cathodes for use in rechargeable lithium batteries by linear sweep voltammetry (LSV) Part II. Experimental study using thin films, single particles and composite electrodes
- 2001
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Ingår i: Journal of Electroanalytical Chemistry. - 0022-0728 .- 1873-2569. ; 509:2, s. 139-147
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Tidskriftsartikel (refereegranskat)abstract
- Thin films, single particles and a composite electrode of the cathode material LiMn2O4 in the lithium battery system were investigated by linear sweep voltammetry (LSV) in 1 M LiClO4 + PC:EC. The experimental data were compared to and analysed by mathematical models described in Part I of this work. Analysis of the measured peak potential. E-p, showed clearly that the larger the characteristic length, the larger is the potential peak shift., at a given sweep rate. From the observations of the measured peak current behaviour, I-p, it seems that the composite electrode and the single particles are semi-infinite diffusion limited at all sweep rates applied. For the thin films, when increasing the sweep rate, a transition from finite to semi-infinite mass transfer limitation is indicated. A model based on solid-phase diffusion, interfacial charge transfer and an external IR-drop could fairly well be fitted to the experimental data measured on a single electrode system at a given sweep rate. It was found that the determined parameter values. i.e. solid-phase diffusion coefficient and the IR-drop, vary greatly with sweep rate and characteristic length. These results indicate that the physical description used is an oversimplification for describing the reaction mechanism in LiMn2O4.
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| 5. |
- Hjelm, A. K., et al.
(författare)
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Investigation of LiMn2O4 cathodes for use in rechargeable lithium batteries by linear sweep voltammetry Part I. Theoretical study
- 2001
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Ingår i: Journal of Electroanalytical Chemistry. - 0022-0728 .- 1873-2569. ; 506:2, s. 82-91
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Tidskriftsartikel (refereegranskat)abstract
- Linear sweep voltammetry (LSV) is a well-known tool for electrochemical investigations. Different aspects on the use of LSV in the study of an intercalation electrode in the rechargeable lithium battery system have been studied. Mathematical models were used to simulate voltammetry responses for an intercalation material influenced by solid phase diffusion, charge transfer and IR-drop. It was shown how the peak potential and the peak current density vary with sweep rate for different rate determining processes. The simulations show that finite and semi-infinite diffusion is relatively easy to distinguish and also, these two processes behave differently from processes influenced by charge transfer and an external IR-drop. However, the separation of charge transfer and IR-drop is difficult. The use of the convolution sweep voltammetry method was also investigated. It was found that finite diffusion and a non-zero initial concentration limit the applicability in these systems.
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| 6. |
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| 7. |
- Brannvall, K, et al.
(författare)
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Cystatin-B is expressed by neural stem cells and by differentiated neurons and astrocytes
- 2003
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 0006-291X .- 1090-2104. ; 308:2, s. 369-374
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Tidskriftsartikel (refereegranskat)abstract
- Mutation in the gene encoding cystatin-B (CSTB) has been shown to cause progressive myoclonus epilepsy. Mice with a gene deletion of CSTB exhibit increased apoptosis of specific neurons but the physiological role of CSTB in brain cells is not fully understood. In the present study, we have examined the expression of CSTB in neural stem cells (NSC) and in differentiating mature brain cells. The results show that CSTB is present in embryonic and adult NSC and in the neuroepithelium. CSTB was expressed by both neurons and glial cells differentiated from NSC and in hippocampal cultures. CSTB localized mainly to the nucleus in NSC and in neurons, whilst in astrocytes CSTB was also in the cytoplasm. Double labeling showed that CSTB was present in the lysosomes in glial cells. The results demonstrate a nuclear expression of CSTB in NSC and in neurons, suggesting novel function for this molecule. (C) 2003 Elsevier Inc. All rights reserved.
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| 8. |
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| 9. |
- Eriksson, T., et al.
(författare)
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Kinetic study of LiMn2O4 cathodes by in situ XRD with constant-current cycling and potential stepping
- 2002
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 149:9, s. A1164-A1170
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Tidskriftsartikel (refereegranskat)abstract
- The structure and kinetics of LiMn2O4 electrodes have been investigated by in situ X-ray diffraction (XRD) measurements using a novel three-electrode in situ XRD cell, where the reference electrode is sited on the reverse side of the working electrode to facilitate accurate determination of the electrode potential. The use of ballmilling during electrode preparation resulted in a high level of utilization at high charge/discharge rates of LiMn2O4-based electrodes in both structural and electrochemical studies. No evidence of Li concentration gradients in the solid material could be observed from XRD, thus excluding solid-phase diffusion and also phase boundary movement, as described by Fick's law, as the rate-limiting step.
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| 10. |
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| 11. |
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| 13. |
- Hjelm, A. K., et al.
(författare)
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Electrochemical investigation of LiMn2O4 cathodes in gel electrolyte at various temperatures
- 2002
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Ingår i: Electrochimica Acta. - 0013-4686 .- 1873-3859. ; 48:2, s. 171-179
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Tidskriftsartikel (refereegranskat)abstract
- A composite lithium battery electrode of LiMn2O4 in combination with a gel electrolyte (1 M LiBF4/24 wt% PMMA/1:1 EC:DEC) has been investigated by galvanostatic cycling experiments and electrochemical impedance spectroscopy (EIS) at various temperatures, i.e. -3 < T < 56 degreesC, For analysis of EIS data, a mathematical model taking into account local kinetics and potential distribution in the liquid phase within the porous electrode structure was used. Reasonable values of the double-layer capacitance, the exchange-current density and the solid phase diffusion were found as a function of temperature. The apparent activation energy of the charge-transfer ( similar to 65 kJ mol(-1)), the solid phase transfer ( similar to 45 kJ mol(-1)) and of the ionic bulk and effective conductance in the gel phase ( similar to 34 kJ mol(-1)), respectively, were also determined, The kinetic results related to ambient temperature were compared to those obtained in the corresponding liquid electrolyte. The incorporated PMMA was found to reduce the ionic conductivity of the free electrolyte, and it was concluded that the presence of 24 wt% PMMA does not have a significant influence on the kinetic properties of LiMn2O4.
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| 14. |
- Hjelm, A. K., et al.
(författare)
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Experimental and theoretical analysis of LiMn2O4 cathodes for use in rechargeable lithium batteries by electrochemical impedance spectroscopy (EIS)
- 2002
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Ingår i: Electrochimica Acta. - 0013-4686 .- 1873-3859. ; 47:11, s. 1747-1759
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Tidskriftsartikel (refereegranskat)abstract
- A comparative study of the impedance response measured with composite electrodes and thin film electrodes of LiMn2O4 was conducted. The electrodes were prepared on different current collectors (i.e. aluminium, carbonised aluminium and gold) and the experiments were run at various state-of-discharge (SOD) and liquid electrolyte compositions. The impedance response was shown to be strongly dependent on the current collector used. It was demonstrated that the high-to-medium frequency semicircle can be attributed to the contact resistance between the current collector and the active electrode material and that the medium-to-low frequency semicircle can be ascribed to the active electrode material. For the analysis, a mathematical model based on a resistance between the current collector and the active electrode material, interfacial-charge transfer coupled to the double-layer charging and solid-phase diffusion was developed. Potential distribution due to porous electrode effects was also considered, Fitting the model to experimental data enabled reasonable values of the exchange-current density, the double-layer capacitance and the solid-phase diffusion coefficient. However, the very low fitted value of the effective conductivity in the liquid phase indicates that this model does not give a satisfying description of the intercalation process of LiMn2O4.
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| 15. |
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| 17. |
- Hjelm, Mats, et al.
(författare)
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Monte Carlo study of high-field carrier transport in 4H-SiC including band-to-band tunneling
- 2003
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 93:2, s. 1099-1107
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Tidskriftsartikel (refereegranskat)abstract
- A full-band ensemble Monte Carlo simulation has been used to study the high-field carrier transport properties of 4H-SiC. The complicated band structure of 4H-SiC requires the consideration of band-to-band tunneling at high electric fields. We have used two models for the band-to-band tunneling; one is based on the overlap test and the other on the solution of the multiband Schrodinger equations. The latter simulations have only been performed for holes in the c-axis direction, since the computer capacity requirement are exceedingly high. Impact-ionization transition rates and phonon scattering rates have been calculated numerically directly from the full band structure. Coupling constants for the phonon interaction have been deduced by fitting of the simulated low-field mobility as a function of lattice temperature to experimental data. Secondary hot electrons generated as a consequence of hole-initiated impact ionization are considered in the study for both models of band-to-band tunneling. When the multiband Schrodinger equation model is used for holes in the c-axis direction, a significant change in the electron energy distribution is found, since the hole impact-ionization rate is very much increased with this model. The secondary electrons increase the average energy of the electron distribution leading to a significant increase in the electron-initiated impact-ionization coefficients. Our simulation results clearly show that both electrons and holes have to be considered in order to understand electron-initiated impact ionization in 4H-SiC
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| 18. |
- Nilsson, Hans-Erik, et al.
(författare)
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Monte Carlo simulation of high field hole transport in 4H-SiC including band to band tunneling and optical interband transisitons
- 2002
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 314:1-4, s. 68-71
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Tidskriftsartikel (refereegranskat)abstract
- The high field hole transport in 4H-SiC has been studied using a full band Monte Carlo (MC) simulation model that includes band to band tunneling and allows mixing of the band states during carrier drift. Impact ionization coefficients along the c-axis direction have been extracted and compared with experimental data. It is shown that the band to band tunneling mechanism is crucial in order to explain experimental results. The carrier distribution function obtained from the MC simulations has been used to determine the breakdown luminescence spectra coming from interband transitions. Our results are in good agreement with the available experimental luminescence spectra for SiC polytypes, and the importance of including interband tunneling is clearly demonstrated.
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| 19. |
- Nilsson, Hans-Erik, et al.
(författare)
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Monte Carlo simulation of multi-band carrier transport in semiconductor materials with complex unit cells
- 2001
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Ingår i: SISPAD 2001, International conference on Simulation of Semiconductor Processes and devices, september 5-7, 2001, Athens, Greece. - 3211837086 ; , s. 214-217
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In a traditional Monte Carlo (MC) model the carrier preserves its band identity during the free flight between scatterings. However, this assumption may not be valid in semiconductor materials with complex unit cell. A new model is needed where the traditional way to use classical equations during the free flight between scattering is replaced by a fully quantum mechanical model of the Bloch carrier dynamics between scattering events. In this work we present such a model along with simulated results of the hole initiated impact ionization coefficients of 4H-SiC
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| 20. |
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| 21. |
- Ullen, A., et al.
(författare)
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Additive/synergistic antitumoral effects on prostate cancer cells in vitro following treatment with a combination of docetaxel and zoledronic acid
- 2005
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Ingår i: Acta Oncol. - : Informa UK Limited. - 0284-186X .- 1651-226X. ; 44:6, s. 644-50
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Tidskriftsartikel (refereegranskat)abstract
- Once bone metastasized and androgen independent, prostate cancer is often associated with skeletal morbidity and disability. New treatment modalities that can palliate symptoms from the skeleton and inhibit further progression are warranted. In this study, the antitumoral effects following treatment with a combination of docetaxel and the new generation bisphosphonate, zoledronic acid, were investigated on two hormone-refractory prostate cancer cell lines: PC3 and DU145. The prostate cancer cells were treated with increasing concentrations of zoledronic acid in the absence or presence of docetaxel. Toxicity was measured using fluorometric microculture cytotoxic assay technique. A concentration of 25 microM, zoledronic acid reduced the viable cell number to 68% and 98% for PC3 and DU145 cells respectively. Docetaxel, on the other hand, at a concentration of 0.1 ng/ml, had no effect on the viability. However, a combination of zoledronic acid and docetaxel reduced the cell number to 60% and 81% respectively. Furthermore, zoledronic acid in the concentration range 12.5 microM-50 microM enhanced the antitumoral effects of docetaxel (0.01-1 ng/ml) in an additive and/or synergistic manner for both cell lines. These data support the hypothesis that zoledronic acid, in addition to having bone resorption inhibiting properties, also exhibits anti-tumoral effects. It also appears that combined treatment with docetaxel causes additive and/or synergistic cytostatic effects on prostate cancer cells.
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