| 31. |
- Annerbrink, Kristina, 1974, et al.
(författare)
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Associations between the angiotensin-converting enzyme insertion/deletion polymorphism and monoamine metabolite concentrations in cerebrospinal fluid
- 2010
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Ingår i: Psychiatry Research. - : Elsevier BV. - 1872-7123 .- 0165-1781. ; 179:2, s. 231-234
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Tidskriftsartikel (refereegranskat)abstract
- Angiotensin II has been suggested to influence central dopamine and serotonin turnover. Since the angiotensin-converting enzyme (ACE) plays a key role in angiotensin regulation by converting inactive angiotensin 1 to active angiotensin II, we hypothesised that the functional insertion/deletion (I/D) polymorphism in the ACE gene, which has previously been suggested to be associated with, depression and panic disorder, may influence monoamine activity. A well-established technique for assessing brain monoamine turnover in humans is to measure concentrations of monoamine metabolites in the cerebrospinal fluid (CSF). We thus investigated possible associations between the ACE I/D polymorphism and CSF monoamine metabolite concentrations in a population of healthy male subjects. After having found such an association between the ACE I/D polymorphism and CSF levels of the dopamine metabolite homovanillic acid and the serotonin metabolite 5-hydroxyindoleacetic acid in this sample, I carriers displaying lower levels, we tried to replicate this observation in a population of violent male offenders from which also both CSF and DNA were available. Also in this sample, the same associations were found. Our results suggest that the ACE I/D polymorphism may play a role in the modulation of serotonergic and dopaminergic turnover in men. (C) 2009 Elsevier Ireland Ltd. All rights reserved.
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| 32. |
- Arkeryd, Leif, 1940
(författare)
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A quantum Boltzmann equation for Haldane statistics and hard forces; the space-homogeneous initial value problem
- 2010
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Ingår i: Communications in mathematical physics. - : Springer Science and Business Media LLC. - 0010-3616 .- 1432-0916. ; 298:2, s. 573-583
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Tidskriftsartikel (refereegranskat)abstract
- The paper considers equations of Boltzmann type for Haldane exclusion statistics. Existence and some basic properties of the solutions are studied for the space homogeneous initial value problem with hard forces and angular cut-off. The approach uses strong L-1 compactness. Some of the technical estimates are based on L-infinity decay properties, and the control of the filling factor on range estimates for the solutions.
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| 33. |
- Arkeryd, Leif, 1940, et al.
(författare)
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Stability for Rayleigh-Benard convective solutions of the Boltzmann equation
- 2010
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Ingår i: Archive for rational mechanics and analysis. - : Springer Science and Business Media LLC. - 0003-9527 .- 1432-0673. ; 198:1, s. 125-187
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Tidskriftsartikel (refereegranskat)abstract
- We consider the Boltzmann equation for a gas in a horizontal slab, subject to a gravitational force. The boundary conditions are of diffusive type, specifying the wall temperatures, so that the top temperature is lower than the bottom one (Benard setup). We consider a 2-dimensional convective stationary solution, which for small Knudsen numbers is close to the convective stationary solution of the Oberbeck-Boussinesq equations, near and above the bifurcation point, and prove its stability under 2-d small perturbations, for Rayleigh numbers above and close to the bifurcation point and for small Knudsen numbers.
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| 34. |
- Arvidsson, Yvonne, 1960, et al.
(författare)
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Hypoxia stimulates CXCR4 signalling in ileal carcinoids.
- 2010
-
Ingår i: Endocrine-related cancer. - 1479-6821. ; 17:2, s. 303-316
-
Tidskriftsartikel (refereegranskat)abstract
- Tumour hypoxia is associated with increased metastatic potential and resistance to radiotherapy and chemotherapy. Ileal carcinoids are usually metastatic at the time of diagnosis and respond poorly to chemotherapy. The aim of this study was to investigate the extent of hypoxia in ileal carcinoids and the response of tumour cells to induced hypoxia. VEGF, CA-IX, HIF-1alpha and HIF-2alpha were studied by immunohistochemistry in biopsies from 24 patients with ileal carcinoids. All hypoxic markers were shown to be highly expressed in localized areas of the tumours irrespective of tumour location or stage. However, HIF-2alpha expression was significantly higher in distant metastases compared to primary tumours in the same patient. Global gene expression profiling of GOT1 carcinoid cells revealed a marked response to hypoxia. Expression of genes related to epithelial-to-mesenchymal transition (EMT) and development was altered including increased expression of the chemokine receptor CXCR4, an important regulator of invasive growth and metastasis formation. High expression of CXCR4 was confirmed by immunohistochemistry in tumour biopsies. Stimulation of GOT1 cells by the CXCR4 ligand CXCL12 (SDF-1) activated the MAPK p42/44 signalling pathway and increased tumour cell migration. We conclude that ileal carcinoids contain hypoxic areas expressing HIF-1alpha, and HIF-2alpha and CXCR4. Signalling through the CXCL12-CXCR4 axis may contribute to the metastatic potential of ileal carcinoids. Targeting of HIFs and/or the CXCR4 signalling pathway may offer new therapeutic strategies for this carcinoid tumour disease.
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| 35. |
- Asadzadeh, Mohammad, 1952, et al.
(författare)
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A posteriori error estimates in a globally convergent FEM for a hyperbolic coefficient inverse problem
- 2010
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Ingår i: Inverse Problems. - : IOP Publishing. - 0266-5611 .- 1361-6420. ; 26:11
-
Tidskriftsartikel (refereegranskat)abstract
- This study concerns a posteriori error estimates in a globally convergent numerical method for a hyperbolic coefficient inverse problem. Using the Laplace transform the model problem is reduced to a nonlinear elliptic equation with a gradient dependent nonlinearity. We investigate the behavior of the nonlinear term in both a priori and a posteriori settings and derive optimal a posteriori error estimates for a finite-element approximation of this problem. Numerical experiments justify the efficiency of a posteriori estimates in the globally convergent approach.
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| 36. |
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| 37. |
- Asadzadeh, Mohammad, 1952, et al.
(författare)
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Asymptotic error expansions for the finite element method for second order elliptic problems in R_N, N>=2, I: Local interior expansions
- 2010
-
Ingår i: SIAM Journal on Numerical Analysis. - : Society for Industrial & Applied Mathematics (SIAM). - 0036-1429 .- 1095-7170. ; 48:5, s. 2000-2017
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Tidskriftsartikel (refereegranskat)abstract
- Our aim here is to give sufficient conditions on the finite element spaces near a point so that the error in the finite element method for the function and its derivatives at the point have exact asymptotic expansions in terms of the mesh parameter h, valid for h sufficiently small. Such expansions are obtained from the so-called asymptotic expansion inequalities valid in RN for N ≥ 2, studies by Schatz in [Math. Comp., 67 (1998), pp. 877-899] and [SIAM J. Numer. Anal., 38 (2000), pp. 1269-1293].
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| 38. |
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| 39. |
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| 40. |
- Asadzadeh, Mohammad, 1952, et al.
(författare)
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Galerkin methods for primary ion transport in inhomogeneous media
- 2010
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Ingår i: Kinetic and Related Models. - : American Institute of Mathematical Sciences (AIMS). - 1937-5093 .- 1937-5077. ; 3:3, s. 373-394
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Tidskriftsartikel (refereegranskat)abstract
- This paper concerns the energy deposition of high-energy (e.g., approximate to 50 - 500 MeV) proton and carbon ions and high-energy electrons (of approximate to 50 MeV), in inhomogeneous media. Our goal is to develop a flexible model incorporated with the analytic theory for ions based on bipartition and Fokker-Planck developments. Both procedures are leading to convection dominated convection diffusion equations. We study convergence for semi-discrete and fully discrete approximations of a such obtained equation, for abroad beam model, using the standard Galerkin and streamline diffusion finite element methods. The analytic broad beam model of the light ion absorbed dose were compared with the results of the modified Monte Carlo (MC) code SHIELD-HIT+ and those of Galerkin streamline diffusion approach.
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