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Inactin is a long lasting anesthetic agent commonly used in rat studies, but is also shown to exert physiological effects such as reducing renal blood flow, glomerular filtration rate and depressing tubular transport capacity. The effect of inactin on isolated kidney mitochondria is unknown and may be important when studying related topics in anaesthetized animals. The aim of this study was to determine whether inactin exerts effects on mitochondrial function and production of reactive oxygen species. Kidney mitochondrial function and production of reactive oxygen after acutely (5 min) or longer (1.5 hour) anesthetizing rats with inactin was evaluated using high-resolution respirometry. The results demonstrate that inactin significantly improves respiratory control ratio, inhibits complex I in the mitochondrial respiratory chain, reduce both unregulated proton leak and time dependently reduce the regulated proton leak via uncoupling protein-2 and adenine nucleotide translocase. Inactin also contributes to increased mitochondrial hydrogen peroxide production. In conclusion, inactin exerts persistent effects on mitochondrial function and these profound effects on mitochondrial function should to be considered when studying mitochondria isolated from animals anesthesized with inactin. Funding Agencies|Swedish Research Council; Swedish Diabetes Foundation; Ake Wiberg Foundation; Family Ernfors Foundation; Swedish Society for Medical Research; Lundbeck Foundation; Danish Diabetes Academy - Novo Nordisk Foundation

PURPOSE: Vulnerable atherosclerotic plaques are structurally weak and prone to rupture, presumably due to local oxidative stress. Redox active iron is linked to oxidative stress and the aim of this study was to investigate the distribution of Fe(III) in carotid plaques and its relation to vulnerability for rupture. METHODS: Atherosclerotic plaques from 10 patients (three asymptomatic and seven symptomatic) were investigated. Plaque vulnerability was classified using ultrasound and immunohistochemistry and correlated to Fe(III) measured by electron paramagnetic resonance spectroscopy. RESULTS: Large intra-plaque Fe(III) variations were found. Plaques from symptomatic patients had a higher Fe(III) concentration as compared with asymptomatic plaques (0.36 ± 0.21 vs. 0.06 ± 0.04 nmol Fe(III)/mg tissue, P

Den här uppsatsen handlar om de sovjetiska psykologerna Vygotskij och Leontjevs teoretiska perspektiv på lek, så som Vygotkji presenterar sin teori i förläsningen Lekens roll i barnets psykiska utveckling 1933 (1981) och så som Leontjev presenterar sin teori i artikeln Lekens psykologiska grundvalar i förskoleåldern 1944 (1982). Den här uppsatsen bygger på en kvalitativ hermeneutisk textanalys av dessa två källor, och ställer sig frågan vad Vygotskijs och Leontjevs teorier betyder? Analysen anlägger dels ett hermeneutiskt historiskt perspektiv och dels ett nutids historiskt pedagogiskt perspektiv. För det nutidspedagogiska perspektivet använder jag mig av det skandinaviska forskningsfältet lekpedagogik, framför allt Birgitta Knutsdotter Olofsson, Fredrik Ole Lillemyr och Gunilla Lindqvist. För det hermeneutiskt historiska perspektivet använder jag mig av en kvalitativ textanalys där jag har systematiserat de två texterna i vardera tre analysteman. Vygotskijs föreläsning har jag sammanfattat och tolkat utifrån följande analysteman: förändrade handlingsmotiv, separationen mellan det visuella fältet och betydelsefältet och sambandet mellan rollek och regellek. Leontjevs artikel har jag sammanfattat och tolkat utifrån analystemana förändrade handlingsmotiv, leken som reproduktion och sambandet mellan rollek och regellek. Samtliga av analystemana är hermeneutiska delar av respektive texters helheter. Temana har jag analyserat dels som bryt- och beröringspunkter mellan Vygotskij och Leontjev och dels utifrån de begrepp som ligger till grund för den kulturhistoriska teorin.I analysen kommer jag fram till att förändrade handlingsmotiv ligger till grund för både Vygotskij och Leontjevs teorier, även om de skiljer sig åt något i sina respektive definitioner. Vidare kommer jag fram till att både Vygotskij och Leontjev baserar sin syn på utvecklingen av barns lek från rollek till regellek på en liknande historiegenetisk analys. Den stora skillnaden, som jag har funnit i min analys, är att Leontjev behandlar leken som ett yttre fenomen, som en verksamhet, medan Vygotskij behandlar leken som ett inre-yttre fenomen. Alltså som en verksamhet men också som en inre process där barnets idéer, emotioner och fantasi driver leken. This essay discusses the theories on children’s play of two sovjetic psychologists: Lev S. Vygotsky and Aleksei N. Leontiev. It focuses specifically on Vygotsky’s lecture Play and its role in the Mental Development of the Child from 1933, and on Leontiev’s article The Psychological Principles of Preschool Play from 1944. Through a qualitative hermeneutic textual analysis of these two sources, the essay explores the meaning of Vygotsky’s and Leontiev’s theories, both from a hermeneutical, historical perspective, and a contemporary historical, educational perspective. The contemporary pedagogical perspective is based primarily on the Scandinavian research field of “play pedagogy”, and the research of Birgitta Knutsdotter Olofsson, Fredrik Ole Lillemyr and Gunilla Lindqvist. The hermeneutical, historical perspective is present through a qualitative text analysis. In this analysis, the contents of the two texts are systematized and interpreted with the use of three analytical themes. In Vygotsky’s lecture, the following themes are identified: changing motives of action, the separation between the visual field and the meaning field and the relationship between role play and rule play. In Leontiev’s article, these three themes are found: changing motives of action, play as reproduction, and the relationship between role play and rule play. All of the analytical themes are hermeneutic parts of the texts as a whole. The themes are analyzed both as differences and similarities between Vygotsky and Leontiev, and also as concepts that form the basis for the cultural-historical theory. The analysis show that the theme of changing action motives is at the base of both Vygotsky’s and Leontiev’s theories, although their definitions of this theme differ somewhat. The study also found that both Vygotsky and Leontiev based their theories on the development of children's play from role play to rule play on a similar historical genetic analysis. The major difference found between Vygotsky and Leontiev is that Leontjev treats play primarily as an external phenomenon and as an external activity, whereas Vygotsky treats play both as an external activity, like Leontiev, and as an internal process, in which the child's ideas, emotions and imagination drives play forward.

Syftet med uppsatsen är att studera sambandet mellan länders utdelningsmönster och corporate governance system samt förklara varför denna koppling ser ut som den gör med hjälp av den teoribildning som finns på området. Till undersökningen har tre EU länder valts. För att kartlägga ländernas utdelningsmönster har finansiell data insamlats för respektive lands samtliga noterade företag. Dessa data har sammanställts till tre nyckeltal gällande utdelningsnivå för varje land och år mellan år 1989 till år 2007. Det finns skillnader mellan länderna både beträffande corporate governance system och beträffande utdelningsmönster. De viktigaste faktorerna inom corporate governance som i uppsatsen visat sig haft störst betydelse för utdelningsmönstrets utseende är ägarstrukturen samt kapitalmarknadens struktur. Störst andel spritt ägande och starkast inflytande från aktiemarknaden återfinns i Storbritannien, följt av Sverige och sist Tyskland som tvärtom kännetecknas av ett mycket koncentrerat ägande och lägre påverkan från aktiemarknaden. Utdelningsmönstret har samma ordningsföljd, med Storbritannien som det land med högst utdelningsnivå. Kopplingen mellan corporate governance system och utdelningsmönster kan enligt uppsatsens resultat förklaras med hjälp av principal-agentteorin och bird in the hand teorin samt till viss del av signaleringsteorin. Däremot kunde inte skattepreferensteorin förklara sambandet.

A dosimetry system using lithium formate monohydrate (HCO2Li center dot H2O) as detector material and electron paramagnetic resonance (EPR) spectroscopy for readout has been used to measure absorbed dose distributions around clinical Ir-192 sources. Cylindrical tablets with diameter of 4.5 mm, height of 4.8 mm, and density of 1.26 g/cm(3) were manufactured. Homogeneity test and calibration of the dosimeters were performed in a 6 MV photon beam. Ir-192 irradiations were performed in a PMMA phantom using two different source models, the GammaMed Plus HDR and the microSelectron PDR-v1 model. Measured absorbed doses to water in the PMMA phantom were converted to the corresponding absorbed doses to water in water phantoms of dimensions used by the treatment planning systems (TPSs) using correction factors explicitly derived for this experiment. Experimentally determined absorbed doses agreed with the absorbed doses to water calculated by the TPS to within +/- 2.9%. Relative standard uncertainties in the experimentally determined absorbed doses were estimated to be within the range of 1.7%-1.3% depending on the radial distance from the source, the type of source (HDR or PDR), and the particular absorbed doses used. This work shows that a lithium formate dosimetry system is well suited for measurements of absorbed dose to water around clinical HDR and PDR Ir-192 sources. Being less energy dependent than the commonly used thermoluminescent lithium fluoride (LiF) dosimeters, lithium formate monohydrate dosimeters are well suited to measure absorbed doses in situations where the energy dependence cannot easily be accounted for such as in multiple-source irradiations to verify treatment plans. Their wide dynamic range and linear dose response over the dose interval of 0.2-1000 Gy make them suitable for measurements on sources of the strengths used in clinical applications. The dosimeter size needs, however, to be reduced for application to single-source dosimetry. Original Publication: Laura Antonovic, Håkan Gustafsson, Gudrun Alm Carlsson and Åsa Carlsson Tedgren, Evaluation of a lithium formate EPR dosimetry system for dose measurements around Ir-192 brachytherapy sources, 2009, MEDICAL PHYSICS, (36), 6, 2236-2247. http://dx.doi.org/10.1118/1.3110068 Copyright: American Institute of Physics http://www.aip.org/

Electron paramagnetic resonance (EPR) dosimetry using the well established dosimeter material alanine is a generally accepted dosimetric method for measurements of high absorbed doses. Alanine EPR dosimetry is however not sensitive enough for high precision measurements of low (< 5 Gy) absorbed doses using reasonably measurement times and small dosimeters. It has therefore not been possible to fully exploit the benefits of EPR dosimetry for applications in radiation therapy. The aim of this thesis was to show that sensitive EPR dosimetry is a competitive method for applications in radiation therapy fulfilling the requirements of measurement precision. Our strategy for reaching this goal was to search for new, more sensitive, EPR dosimeter materials fulfilling the criteria of being tissue equivalent, having a high radical yield and having a narrow EPR spectrum suitable for dosimetry. The best materials were found among formates and dithionates. Doping with small amounts of metal ions and recrystallisation in D2O were tested to further increase the sensitivity. Four promising candidate materials were tested regarding radical stability and dose response and among them lithium formate was chosen for dosimetry in radiation therapy applications. A high precision EPR dosimetry method was developed using lithium formate. The method included the development of a production method for EPR dosimeters with very homogenous shape, mass and composition. A read-out process was developed with maximal measurement precision for reasonably short measurement times. The method also included a dosimeter quality control before actual dose measurements. Measurement accuracy was controlled for every new dosimeter batch. This high precision lithium formate EPR dosimetry method was evaluated for pretreatment verifications of intensity modulated radiation therapy (IMRT) treatment plans. The precision and accuracy was shown to be sufficient (< 5 %) for measurements of doses above 1.5 Gy using one single dosimeter and a measurement time of 15 minutes. The described evaluation is therefore a demonstration of the improved precision at low dose determinations that is available with our sensitive EPR dosimeter materials. While the EPR signal intensity is proportional to absorbed dose, the signal shape is in some cases dependent on the radiation quality. A new method is presented for simultaneous measurements of beam LET (linear energy transfer) and absorbed dose in heavy charged particle beams using potassium dithionate EPR dosimetry. The study shows that when irradiating a dosimeter with 35 MeV carbon ions, the ratio of the signal amplitudes from two radicals in potassium dithionate vary along the track indicating a dependence on linear energy transfer, LET. Potassium dithionate may therefore be a promising EPR dosimeter material for simultaneous measurements of absorbed dose and LET in heavy charged particle radiation fields.