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- Engdahl, Ulrica, 1970-
(author)
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Att vara som/den ’en’ är : En etisk diskussion om begreppen rättvisa, erkännande och identitet i en trans*kontext
- 2011
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Doctoral thesis (other academic/artistic)abstract
- I denna avhandling pekar jag på misserkännande av könsvariation och orättvisor som följer av detta som en viktig orättvise- och misserkännandeproblematik. Den övergripande ambitionen är att diskutera en möjlig(görande) etik. Det innebär att den är möjlig att formulera och att intentionen är människors möjliggörande. Målet är att förstå begreppen rättvisa och erkännande i relation till identitet och identitetspolitik, genom en tankefigur som jag har kallat ’att vara som/den en är.’ I syfte att konkretisera den teoretiska diskussionen är den placerad i en trans*kontext. Denna exemplifieras av ett transbiografiskt och ett transpolitiskt kapitel, vilka presenterar identitetserfarenheter och politiska och moraliska ståndpunkter som relateras till dessa. Genom att studera transpolitiken blir det möjligt att identifiera uttryck för moraliska brister vad gäller rättvisa och erkännande, vad Iris Marion Young förstår som ’normativa möjligheter.’ I det transbiografiska materialet framkommer erfarenheter av osynlighet och dess ontologiska konsekvenser som en sådan moralisk brist. Det visar på vikten av synlighet och lyssnande som moraliska nödvändigheter för att möjliggöra könsvarierade identiteter och existenser genom att begreppsliggöra föreställningar om könsvariation. Figuren ’att vara som/den en är’ är tänkt att ge utrymme för en diskussion om vardagliga identitetserfarenheter och dess konsekvenser utan att iscensätta begreppets problematiska epistemologiska och ontologiskt begränsande konsekvenser. Avhandlingen resulterar i ett förslag på en möjlig(görande) etik med öppna och flexibla erkännandeprinciper samt en specificering av dessa så att de kan fungera som en transmöjliggörande etisk vägledning.
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| 2. |
- Fakhrzadeh, Azadeh, 1981-
(author)
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Computerized Cell and Tissue Analysis
- 2015
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Doctoral thesis (other academic/artistic)abstract
- The latest advances in digital cameras combined with powerful computer software enable us to store high-quality microscopy images of specimen. Studying hundreds of images manually is very time consuming and has the problem of human subjectivity and inconsistency. Quantitative image analysis is an emerging field and has found its way into analysis of microscopy images for clinical and research purposes. When developing a pipeline, it is important that its components are simple enough to be generalized and have predictive value. This thesis addresses the automation of quantitative analysis of tissue in two different fields: pathology and plant biology.Testicular tissue is a complex structure consisting of seminiferous tubules. The epithelial layer of a seminiferous tubule contains cells that differentiate from primitive germ cells to spermatozoa in a number of steps. These steps are combined in 12 stages in the cycle of the seminiferous epithelium in the mink. The society of toxicological pathology recommends classifying the testicular epithelial into different stages when assessing tissue damage to determine if the dynamics in the spermatogenic cycle have been disturbed. This thesis presents two automated methods for fast and robust segmentation of tubules, and an automated method of staging them. For better accuracy and statistical analysis, we proposed to pool stages into 5 groups. This pooling is suggested based on the morphology of tubules. In the 5 stage case, the overall number of correctly classified tubules is 79.6%.Contextual information on the localization of fluorescence in microscopy images of plant specimen help us to better understand differentiation and maturation of stem cells into tissues. We propose a pipeline for automated segmentation and classification of the cells in a whole cross-section of Arabidopsis hypocotyl, stem, or root. As proof-of-concept that the classification provides a meaningful basis to group cells for fluorescence characterization, we probed tissues with an antibody specific to xylem vessels in the secondary cell wall. Fluorescence intensity in different classes of cells is measured by the pipeline. The measurement results clearly show that the xylem vessels are the dominant cell type that exhibit a fluorescence signal.
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| 4. |
- Zhang, Liyan, 1964-
(author)
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Lipoprotein lipase-unstable on purpose?
- 2007
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Doctoral thesis (other academic/artistic)abstract
- Lipoprotein lipase (LPL) is a central enzyme in lipid metabolism. It is a non-covalent, homodimeric and N-glycosylated protein, which is regulated in a tissue-specific manner and is dependent on an activator protein, apolipoprotein CII. Dissociation of active LPL dimers to monomers leads to loss of activity. This was previously found to be an important event in the rapid regulation of LPL in tissues. The mechanisms involved in the processing of LPL to active dimers, as well as in LPL inactivation through monomerization, were unknown. We have investigated the folding properties of the LPL protein, in particular the requirements for LPL to attain its active quaternary structure and to remain in the native conformation. On expression of LPL in insect cells we found that most of the LPL protein was synthesized in an inactive monomeric form. By co-expression of LPL with human molecular haperones, especially with calreticulin (CRT), the activity of LPL increased greatly, both in the cells and in the media. The effect of CRT on LPL activity was not due to increased levels of the LPL protein, but was due to an increased proportion of active dimeric LPL. Co-immunoprecipitation experiments showed direct interaction between LPL and CRT supporting the idea that this ER-based molecular chaperone supports the formation of active LPL dimers. We showed that, bis-ANS, the aromatic hydrophobic probe 1,1.-bis(aniline)-4,4.- bis(naphthalene)-8,8.disulfonate, can be used to obtain specific information about the interaction of LPL with lipid substrates and with apoCII. Bis-Ans was found to be a potent inhibitor of LPL activity, but apoCII prevented the inhibition. Our results suggest that bis-Ans binds to three exposed hydrophobic sites, of which one is at or close to the binding site(s) for apoCII. In studies of the mechanisms responsible for the spontaneous inactivation of LPL, we showed that active LPL is a dynamic dimer in which the subunits rapidly exchange partners. The rapid equilibrium between dimers and monomers exists even under conditions where LPL is relatively stable. This supports the idea that the dimer is in equilibrium with dimerization-competent, possibly active monomers. This dimerization-competent intermediate was also implicated in studies of the inactivation kinetics. The inactive LPL monomer was found to have a stable, defined conformation irrespective of how it was formed. The main differences in conformation between the inactive monomer and the active dimer were located in the middle part of the LPL subunit. Experiments with bis-Ans demonstrated that more hydrophobic regions were exposed in the inactive monomer, indicating a molten globule conformation. We concluded that the middle part of the LPL subunit is most likely engaged in the formation of the active LPL dimer. The dimerization-competent LPL monomer is a hypothetical conformational state, because it has not been possible to isolate it. To study complete refolding of LPL we used fully denatured LPL and were able to demonstrate that the recovery of LPL activity was about 40% when the denaturant was diluted by a buffer containing 20% human serum and 2M NaCl. Further studies identified calcium as the component in serum that was crucial for the reactivation of LPL. The refolding of LPL was shown to involve at least two steps, of which the first one was rapid and resulted in folded, but inactive monomers. The second step, from inactive monomers to active dimers, was slow and calcium-dependent. Also inactive monomers isolated from human tissue were able to recover activity under the influence of calcium. We proposed that calcium-dependent control of LPL dimerization might be involved in the normal post-translational regulation of LPL activity. In conclusion, LPL is a relatively unstable enzyme under physiological conditions due to its noncovalent dimeric structure. The energy barrier for folding to the active dimer is high and requires the presence of calcium ions and molecular chaperones to be overcome. The dimeric arrangement is probably essential to accomplish rapid down-regulation of LPL activity according to metabolic demand, e.g. in adipose tissue on fasting.
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