| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Gravestijn, Bob, 1974-
(författare)
-
Importance of radial profiles in spectroscopic diagnostics applied to the EXTRAP-T2R reversed-field pinch
- 2003
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The determination of the plasma confinement propertiesdemand data as the electron temperature, the ionic and electrondensity profiles and the radiative emissivity profiles. Thefocus of this thesis is the importance of radial profiles inspectroscopic diagnostics applied to the EXTRAP-T2Rreversed-field pinch.EXTRAP-T2R is a resistive shell reversed-field pinch with amagnetic field shell penetration time much longer than therelaxation cycle time scale. Significant improvements inconfinement properties derived by quantitative plasmaspectroscopy in the vacuum ultraviolet are observed compared tothe previous device EXTRAP-T2. The low level of magneticturbulence and the good magnetic surfaces in the edge regionexplain this observed improvement. A current profile controlexperiment reduces the stochastic transport, which is connectedto the dynamo, and improves the confinement in EXTRAP-T2R evenmore.A comparison of the electron temperature estimated by usinga ratio of line intensities from the same ionization stage ofoxygen and the Thomson scattering system shows that thedifference is explained by the different spatial dependence ofthe excited state populations and the corresponding emissivityof these spectral lines. A collisional radiative model givesestimates for radial profiles of impurities which are notmeasured in EXTRAP-T2R. The estimated profiles can in turn beused to determine the radial profile of the effective ioncharge, the emissivity and finally the radiative power. Asinput, the model uses radial profiles.Neutral hydrogen is predominantly present in the boundaryregion of the plasma. Spectroscopic investigations in this areashow very asymmetric spectral lines of hydrogen due to themovement of atoms. The velocity of the hydrogen atoms dependson the type of plasma-wall interaction and their measurementhelps to identify the different interaction processes. Theexistence of hydrogen molecules in the edge complicates theinterpretation of the line shapes and on the determination ofthe particle confinement time.Keywords:Reversed-field pinch, EXTRAP-T2R, quantitativeplasma spectroscopy, VUV spectroscopy, line-integrated electrontemperature, oxygen, profiles, confinement properties, powerbalance, hydrogen, particle confinement time.
|
|
| 7. |
- Melander, Bob, 1971-
(författare)
-
Probing-Based Approaches to Bandwidth Measurements and Network Path Emulation
- 2003
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The current Internet design is based on a number of principles and paradigms. A central theme of these is that the interior of the network should provide a very simple but generic (and optimized) service, namely best-effort packet forwarding. For the users, a consequence of this design is that performance properties and the behavior of the network can typically only be determined by performing probing-based measurements. Probing means that special packets are injected into the network by one computer while another one receives and collects statistics about those packets. Using this statistical information, it is possible to make inferences about the network and its characteristics. One important characteristic is the bandwidth that is available on the network path between two computers in the Internet. When communicating with each other, the computers should not persistently send data at a higher rate than the available bandwidth since that will eventually lead to packet loss due to the overload. This thesis considers the problem of measuring the available bandwidth of a network path using probing-based methods. To that end, we propose a new method called TOPP. It is designed to probe the network non-intrusively so that the measurements do not jeopardize the stability of the network. In addition to estimating the available bandwidth, TOPP also provides an estimate of the link capacity of the link that limits the available bandwidth. In the second part of this thesis we propose and evaluate different models for trace-driven network path emulation. We also investigate how to probe a network path for the purpose of trace-driven emulation. We show that relatively simple trace-driven models work well for non-responsive UDP-based flows. However, for adaptive TCP flows, these simple models do not seem to perform well. We also find that for the trace-driven models studied, strongly bursty probing schemes (which includes probing by TCP) have undesirable properties and should be avoided.
|
|
| 8. |
- Olsson, Bob, 1969, et al.
(författare)
-
T-cell-mediated cytotoxicity toward platelets in chronic idiopathic thrombocytopenic purpura.
- 2003
-
Ingår i: Nature medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 9:9, s. 1123-4
-
Tidskriftsartikel (refereegranskat)abstract
- Chronic idiopathic thrombocytopenic purpura (ITP) is a bleeding disorder that is characterized by increased platelet destruction and is believed to be autoantibody mediated. In this study, CD3+ T cells from ITP patients had increased expression of genes involved in cell-mediated cytotoxicity. In addition, cytotoxic cell-mediated lysis of autologous platelets was shown in active ITP. Our data suggest that T-cell-mediated cytotoxicity is an alternative mechanism for platelet destruction in ITP.
|
|
| 9. |
- Olsson, Bob, 1969
(författare)
-
The role of GH in the regulation of energy homeostasis, lipid metabolism and cardiovascular function in transgenic mice
- 2001
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was, using two transgenic models, to investigate some metabolic diseases associated with acromegaly e.g. hypertension and alterations in lipid and lipoprotein metabolism. We also studied the positive effect of Growth Hormone (GH), and possible molecular causes, on body composition and energy homeostasis using these GH transgenic models.We have used two different GH transgenic mouse models, one model overexpressing GH generally, controlled by the metallothionine promoter (Mt-bGH), and one model where the GH overexpression is restricted to the CNS, using the glial fibrillary acidic protein promoter (GFAP-bGH).Using telemetric technique, we have found that Mt-bGH transgenic mice have a salt-insensitive hypertension. Furthermore, the Mt-bGH transgenic mice have altered lipoprotein profiles and serum lipids, hyperinsulinemia and hyperglycaemia. Moreover, the hepatic gene expression profiles analysed by micro-array, revealed decreased gene expression of PPARa and SREBP-1 together with decreased expression of genes involved in fatty acid activation, b-oxidation, ketone body formation, lipogenesis, cholesterol metabolism, gluconeogenesis and amino acid catabolism. When analysed by indirect calorimetry, the Mt-bGH transgenic mice also had an increased resting metabolic rate on a normal diet that was enhanced by a Western diet, increased body temperature and increased hepatic gene expression of UCP2. Furthermore, the Mt-bGH transgenic mice had an increased respiratory exchange rate and food intake on both diets but still a lean body composition.The GFAP-bGH mice had an increased food intake resulting in massive obesity along with an increased expression of AGRP and NPY. These mice also had alterations in lipid and lipoprotein metabolism, hyperinsulinemia and pancreatic islet hypertrophy but normal blood glucose levels.GH stimulates food intake by increasing the hypothalamic gene expression of AGRP and NPY. This results in obesity in the GFAP-bGH transgenic mice but the high circulating levels of GH in the Mt-bGH mice, resulting in elevated RMR, body temperature, and T3 levels prevent obesity and result in a lean body composition. We have also found several risk factors for cardiovascular disease in these two GH transgenic models, such as high LDL cholesterol, insulin resistance, hypertension and indications of a decreased reverse cholesterol transport. These models may be useful tools in understanding the underlying mechanisms for cardiovascular disease in patients with acromegaly.
|
|
| 10. |
|
|
