Interventional radiology workers job involves exposure to ionizing radiation. In Sweden monitoring the accumulated dose to the personnel in professions, which involves with ionizing radiation, is mandatory. There are many applications that can visualize and measure the accumulated dose of the personnel.  The DoseAware system is distributed commercially by Philips. This device is mainly developed, designed and made by Unfors Instrument AB in Gothenburg, Sweden with a commercial name Unfors Raysafe i2. It is real time dose visualizer system which uses mostly to increases personnel’s awareness.   This system consists of a number of PDM(personnel dose meters) which detects radiation, and transfers it wirelessly to a monitor that can visualize dose rate. Transferred Data will be analyzed by two softwares, the Dose manager and the DoseView.   This study concerns about Unfors Raysafe i2's functionality, performance and usability of this system as a dosimeter for the staff of an interventional radiology lab. To examine differences to other systems and to validate it against traditional TLD measurement.   The aim of the project is to control how to use the system for training of personnel working in environments with ionizing radiation. The more specific aim is to investigate if it is possible to reduce the accumulated dose by using the device during an interventional procedure.   In this study, the dose aware system was installed At IR-lab of Umeå hospital. The first measurement session was a blind measurement, i.e. the personnel were not able to see their dose. Prior to the second measurement some hints was given them and explanations about working radiation hygiene and after that another measurement session was held, called an ‘’open measurement’’ when they could see the Dose aware system’s monitor that displayed their individual doses.   Comparison between acquired results from both weeks shows a decrease in accumulated dose to the radiologist by almost 20 % (using the workflow ratio between week 1 and 2 as a normalizing factor).

In this thesis we consider the following two fundamental problems for semigroup presentations: 1. Given a semigroup find a presentation defining it. 2. Given a presentation describe the semigroup defined by it. We also establish other related results. After an introduction in Chapter 1, we consider the first problem in Chapter 2, and establish a presentation for the commutative semigroup of integers Zpt. Dually, in Chapter 3 we consider the second problem and study presentations of semigroups related to the direct product of cyclic groups. In Chapter 4 we study presentations of semigroups related to dihedral groups and establish their V-classes structure in Chapter 5. In Chapter 6 we establish some results related to the Schutzenberger group which were suggested by our studies of the semigroup presentations in Chapters 3 and 4. Finally, in Chapter 7 we define and study new classes of semigroups which we call R, L-semi-commutative and semi-commutative semigroups and they were also suggested by our studies of the semigroup presentations in Chapters 3 and 4.

Steven A. [sic] Freeman. / Series title and numbering from publisher's list. / Includes bibliographical references (p. [1]-[3]). / Fellowship support provided by the Organization Studies dept. of the Sloan School of Management, research sponsored by the International Motor Vehicle Project.

<p>Essay 1 (with Tanja Kirjavainen and Roope Uusitalo) analyzes the effects of changes in school spending on changes in student performance. We use a large sample of matriculation examination scores of Finnish senior secondary school students from the years 1990–1998. We estimate fixed-effect panel data models that use the dramatic changes in the school spending caused by the 1990s' recession as identifying variation. According to the results, changes in teaching expenditure did not have a significant effect on the test scores. The grade point average in comprehensive school and the parents’ education are the strongest explanatory variables for student achievement.</p><p>Essay 2 examines which factors predict academic performance at university and compares the predictive values of subject-related entrance exams and indicators of past school performance. The results show that a large fraction of students would be admitted whether the admission was based on entrance exams, past performance or a combination of these, which is the current system. In the fields of engineering, social sciences and sport sciences entrance exams predict both graduation and the number of study credits after four years better than past school performance. In education past school performance is a better predictor of graduation. Changing the admission rule to school grades would affect the average student performance negatively in engineering and social sciences but positively in education. Using only entrance exams would not signifi-cantly change the average student performance in any field.</p><p>Essay 3 (with Roope Uusitalo) evaluates the changes in the times-to-degree at the Finnish universities in the 1990s. In particular, the study evaluates the effect of the 1992 student aid reform that was intended to shorten the duration of university studies. We find that the student aid reform had only a modest effect, and that this effect was limited to the fields with long median durations. Most of the decline in the observed times-to-degree can be explained by an increase in the unemployment rate that reduced student employment opportunities.</p><p>Essay 4 examines how university students' employment decisions affect their labor market success after graduation. The study is based on individual level panel data of Finnish university students from the years 1987–1998. The OLS estimates show that in-school work experience is associated with higher earnings and employment after graduation. Local unemployment rate during enrollment is used as an instrument for endogenous work experience acquisition. Comparing graduates with equal times-to-degree, the IV estimates show that work experience increases earnings considerably one year after graduation. The effect is smaller and statistically insignificant in later years. Taking into account that working usually leads to longer times-to-degree, IV estimates show no significant returns to student employment. </p>

Essay 1 (with Tanja Kirjavainen and Roope Uusitalo) analyzes the effects of changes in school spending on changes in student performance. We use a large sample of matriculation examination scores of Finnish senior secondary school students from the years 1990–1998. We estimate fixed-effect panel data models that use the dramatic changes in the school spending caused by the 1990s' recession as identifying variation. According to the results, changes in teaching expenditure did not have a significant effect on the test scores. The grade point average in comprehensive school and the parents’ education are the strongest explanatory variables for student achievement. Essay 2 examines which factors predict academic performance at university and compares the predictive values of subject-related entrance exams and indicators of past school performance. The results show that a large fraction of students would be admitted whether the admission was based on entrance exams, past performance or a combination of these, which is the current system. In the fields of engineering, social sciences and sport sciences entrance exams predict both graduation and the number of study credits after four years better than past school performance. In education past school performance is a better predictor of graduation. Changing the admission rule to school grades would affect the average student performance negatively in engineering and social sciences but positively in education. Using only entrance exams would not signifi-cantly change the average student performance in any field. Essay 3 (with Roope Uusitalo) evaluates the changes in the times-to-degree at the Finnish universities in the 1990s. In particular, the study evaluates the effect of the 1992 student aid reform that was intended to shorten the duration of university studies. We find that the student aid reform had only a modest effect, and that this effect was limited to the fields with long median durations. Most of the decline in the observed times-to-degree can be explained by an increase in the unemployment rate that reduced student employment opportunities. Essay 4 examines how university students' employment decisions affect their labor market success after graduation. The study is based on individual level panel data of Finnish university students from the years 1987–1998. The OLS estimates show that in-school work experience is associated with higher earnings and employment after graduation. Local unemployment rate during enrollment is used as an instrument for endogenous work experience acquisition. Comparing graduates with equal times-to-degree, the IV estimates show that work experience increases earnings considerably one year after graduation. The effect is smaller and statistically insignificant in later years. Taking into account that working usually leads to longer times-to-degree, IV estimates show no significant returns to student employment.

The fact that nutrition affects education outcomes is accepted by researchers and by policy makers. It is simple. Children cannot learn if they are hungry. The validity of the empirical approaches used to show a causal relationship from nutrition to education is an issue of debate. The presence of unobserved characteristics that influence both variables is the main concern of researchers. The goal of this paper is to study the possibility of overcoming these difficulties using the NHANES III (1988-1994), a cross-section data set with national representation in the US. A set of school outcomes and a dummy that accounts for the "food-insecurity" condition of each child's family are the central variables here. Based on a IVs procedure, it looks for variables that can be used as instruments for the "food-insecurity" condition. The preliminary results indicate that child's height and mother's body mass index are no good instruments to do so. Further research in needed to construct other variables that might turn to be good instruments for food-insecurity.

OBJECTIVE: Previous studies have shown the significant contribution of sympathoinhibition in response to sodium loading to prevent increases in mean arterial blood pressure in salt resistant phenotypes. It has also been shown that brain Gαi2 protein gated signal transduction plays a major role in this pathway, however, the specific mechanisms through which this pathway is activated remain less well understood. The purpose of this study was to elucidate the relative contribution of increased sodium in either the plasma or the cerebrospinal fluid (CSF) to the regulation of mean arterial pressure and natriuresis. Additionally we explored the potential for using the novel CLARITY Imaging technique to identify the relative activity of neurons in areas of the brain thought to play a major role in body fluid homeostasis in response to salt. METHODS: Rats that were pre-treated with either scrambled or Gαi2 oligodeoxynucleotides (ODN), to selectively down regulate brain Gαi2 proteins, were challenged either peripherally or centrally with sodium. Upon sodium loading physiological parameters were measured for two hours after which the animal's brains were recovered for immunohistochemical (IHC) analysis of the paraventricular nucleus, a known regulatory center for body fluid homeostasis and blood pressure regulation. Additionally we adapted a version of the published CLARITY Imaging protocols for optically clearing tissue through application of electrophoretic tissue clearing (ETC) to a larger rat model. RESULTS: In scrambled ODN pre-treated rats we observed a temporary increase in MAP in response to both the peripheral and central sodium challenge. In the Gαi2 ODN pre-treated animals we saw some form of attenuation to this response in both studies, however, where in the peripheral challenge there was an increase in the amount of time that it took the rats to return to normotension with no alteration in natriuresis, in the central challenge there was a large attenuation in natriuresis with no differences in the time to return to baseline MAP. Our IHC analysis also showed a decrease in neuronal activation of paraventricular medial parvocellular neurons in Gαi2 pre-treated rats that were challenged peripherally vs their SCR pre-treated counterparts. No such difference was observed in either of the pre-treatment groups from the central sodium challenge study. In the CLARITY study we found that it is possible to adapt the method for optically clearing tissue to the larger model, however, we encountered several issues related to tissue swelling and peripheral tissue damage. CONCLUSION: Based on our current results it seems evident that there are at least two different mechanisms that activate the cardiovascular regulatory control centers in the brain that prevent long term increases in mean arterial pressure in response to increased salt. It also appears that these two different mechanisms are triggered either by increases in plasma or CSF salinity, though which of these two mechanisms may be directly responsible for the development of salt sensitive hypertension requires further investigation. While we had some success at optically clearing larger tissue volumes through ETC, problems we encountered with maintaining tissue integrity for investigations of intact neural networks prevented us from applying this technique, in its current form, to our investigation of salt sensitive hypertension.

The purpose of these studies was to determine if an immunomodulator was present in caprine serum. Controlled studies demonstrated that CSF-I, material fractionated from caprine serum possessed an immunomodulatory compound. Caprine serum was further fractionated into it?s peptidic components and a small contaminant of immunoglobulin G and albumin (Caprine serum fraction - immunomodulator 2, or CSF-I2). This was refined to a three peptidic isolate collectively identified as tri-peptidic immunostimulant or TPI. CSF-I2 does not possess antibacterial capabilities (as typically characteristic of a cationic peptide or defensin), does not contain a level of endotoxin sufficient to promote a pyrogenic response, and its functional ability to improve animal survival after an infectious challenge does not reside with molecular weight components greater than 10 kilodaltons, effectively excluding the immunoglobins, albumin, cytokines, and collectins. CSF-I2 was able to significantly reduce the mortality observed in chickens (from 80% to 13%) infected with Pasteurella multocida (Willeford et al., 2000), in mice (from 83% to 13.3%) infected with Salmonella typhimurium, and in canines (from 50% to 9.8%) diagnosed with parvovirus. CSF-I2 may well prove to provide prophylactic and therapeutic health benefits to humans. CSF-I2 may effectively combat pathogenesis when used as either an adjunct with conventional therapy (e.g., antibiotics) or when provided as the primary medicant.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Monoamine oxidase (MAO) is a flavin adenine dinucleotide (FAD)-containing enzyme attached to the mitochondrial outer membrane of neurons, glia, and other cells. Its roles include regulation of the levels of biogenic and xenobiotic amines in the brain and peripheral tissues by catalyzing their oxidative deamination. On the basis of their substrate and inhibitor specificities, two isoforms of MAO have been described (A and B). Due to their role in the metabolism of catecholamines neurotransmitters, MAO-A and MAO-B have long been of pharmacological interest. Accordingly, and reversible and irreversible inhibitors of MAO-A and MAO-B have been used in the clinics to treat neurological disorders including depression and Parkinson´s disease. Since the demonstration that I2- imidazoline sites are associated with mitochondrial membranes 15 years ago, several studies have provided evidence that these sites represent regions on MAOs. In line with this view, it has been demonstrated that imidazoline derivatives inhibit MAO activity. This effect has been attributed to a high affinity I2 binding site on MAO-B (I2B) and to a similar lower affinity site on MAO-A (I2A). This study investigated the effect of 4,5-dihydro-1H-imidazole-2-substituted compounds on MAO activity in vitro by spectrophotometric and fluorimetric methods using kynuramine as substrate. Among the compounds that inhibited MAO-A (3c-e, 3j), compound 3d was 73-fold more selective towards MAO-A than MAO-B. Among the compounds that selectively inhibited MAO-B (3g-I, 3k, 3o), imidazoline 3g was shown to be potent with Ki value of 5,3 μM. Some of compounds that selectively bind to I2-sites, such as 3l (benazoline), 3n (2-BFI), and 3p (BU224) showed good inhibitory activity especially against MAO-B. Imidazolines inhibited MAO-A and MAO-B activities in liver with less selectively than in rat brain. The compounds 3d and 3g reversibly inhibited MAO, and kinetics studies showed that compound 3d and 3g inhibited MAO in a mixed manner (decreased Vmax and increased Km values). These results confirm that imidazolines inhibit MAO activity and suggest a relationship between I2 binding site and modulation of central MAO / A monoamina oxidase (MAO) é uma enzima que contém o dinucleotídeo adenina-flavina (FAD) e que está presente na membrana externa da mitocôndria de células neuronais, glia e outras células. Seu papel inclui a regulação dos níveis de aminas biogênicas e xenobióticas no cérebro e em tecidos periféricos pela desaminação oxidativa. Com base na especificidade a substrato e inibidores, são descritas duas isoformas da MAO (A e B). Devido aos seus papéis no metabolismo das catecolaminas neurotransmissoras, a MAO-A e a MAO-B são consideradas farmacologicamente interessantes, e inibidores reversíveis e irreversíveis destas isoformas são usados clinicamente para tratar doenças neurológicas incluindo depressão e doença de Parkinson. Nos últimos 15 anos, desde a demonstração que sítios I2 estão associados com frações da membrana mitocondrial, muitos estudos provem evidências de que estes sítios representam regiões da MAO. Além disso, alguns estudos têm demonstrado que derivados imidazolínicos são capazes de inibir a atividade da MAO. Este efeito tem sido atribuído a sítios I2 de alta afinidade na MAO-B (I2B) e a um sítio similar de baixa afinidade na MAO-A (I2A). Assim, este estudo teve como objetivo investigar o efeito in vitro de compostos 4,5-diidro-1H-imidazol-2-substituídos sobre a atividade da enzima monoamina oxidase através de métodos espectrofotométricos e fluorimétricos usando quinuramina como substrato. Entre os compostos estudados que inibiram preferencialmente a MAO-A (3c-e, 3j) apenas o composto 3d foi seletivo, apresentando um Ki para a MAO-A de aproximadamente 73 vezes menor do que seu Ki para MAO-B. Entre os compostos obtidos que seletivamente inibiram MAO-B (3g-l, 3K, 3o), apenas a imidazolina 3g mostrou ser potente, com valores de Ki de 5,3 μM. Alguns compostos que exercem ligação potente e seletiva à sítios I2, como o 3l (benazolina), 3n (2-BFI) e 3p (BU224) mostraram boa atividade inibitória especialmente contra MAO-B. Em fígado de ratos, as imidazolinas inibiram com menos seletividade a MAO-A e MAO-B quando comparado com cérebro de ratos. Os compostos 3d e 3g inibiram a MAO de maneira reversível e apresentaram inibição de natureza mista (diminuindo o valor de Vmáx e aumentando o valor de Km) sobre a enzima MAO. Estes resultados confirmam que drogas imidazolinas podem inibir a atividade da MAO e sugerem uma relação entre sítios I2 e a modulação da atividade da enzima.

Fundação de Amparo a Pesquisa no Estado do Rio Grande do Sul / Depression is a complex, chronic and disabling psychiatric disease that carries a high social cost. Among the various classes of antidepressants are the monoamine oxidase A (MAO-A) inhibitors that reduce monoamine metabolism. An important site of MAO-A regulation is the imidazoline-2 binding site (I2). In fact, it was recently shown that 2-imidazoline derivatives, such as 2-(2-benzofuranyl)-2-imidazoline (2- BFI), showed good potency and selectivity in inhibiting in vitro the activity of MAO-A, but the antidepressant potential of this compound and its mechanism of action have not been well defined. Therefore, in this study we investigated the antidepressant-like effect of 2-BFI in mice. For this purpose, we evaluated the effects of 2-BFI in two predictive tests of antidepressant-like activity in animals, the tail suspension test (TST) and forced swimming test (FST). The TSC was utilized after the use of specific antagonists of different receptors involved in depression. 2-BFI (100 and 300 μmol/kg, s.c.) significantly reduced the immobility time on the tail suspension test (TST) without changing locomotion in the open field test. The reduced the immobility time of 2-BFI (100 μmol/kg, s.c.) was confirmed with the forced swimming test (FST). The antidepressant-like effect of 2-BFI (100 μmol/kg, s.c.) in the TST was prevented by pretreatment with idazoxan (0.4 μmol/kg, i.p., a I2 site antagonist), methysergide (4 μmol/kg, i.p., a non-selective serotonergic receptor antagonist) and haloperidol (0.1 μmol/kg, i.p., a non-selective dopaminergic receptor antagonist). The anxiolytic effect of 2-BFI was also evaluated, using the elevated plus-maze test. 2-BFI (300 μmol/kg, s.c.) was able to significantly increase the % of number of entries and the % of time spent in the open arms, indicating that it possesses an anxiolytic effect at high doses. In conclusion, these results suggest that the antidepressant-like effect of 2- BFI might involve serotonergic, dopaminergic and imidazoline systems, and then the imidazoline site could represent a new pharmacological target for the treatment of depression. / A depressão é uma doença psiquiátrica complexa, crônica e incapacitante, que acarreta um alto custo social. Dentre as diversas classes de antidepressivos encontram-se os inibidores da monoamina oxidase-A (MAO-A), que reduzem o metabolismo das monoaminas. Um sítio importante para a regulação da MAO-A é o sítio imidazolínico I2. Recentemente, foi demonstrado que derivados 2- imidazolínicos, como o 2-BFI, mostram boa potência e seletividade em inibir a atividade in vitro da MAO em cérebro de ratos, porém o potencial antidepressivo deste composto e seu mecanismo de ação não foram bem definidos. Com base nisso, o objetivo desse trabalho consiste em investigar o efeito tipo-antidepressivo do 2-BFI em camundongos. Para este propósito, foram avaliados os efeitos do 2-BFI em dois testes preditivos de atividade antidepressiva em animais, o teste de suspensão da cauda (TSC) e o teste do nado forçado (TNF). O TSC também foi empregado após o uso de antagonistas específicos de diferentes receptores envolvidos na depressão. O 2-BFI (100 e 300 μmol/kg, s.c.) reduziu significativamente o tempo de imobilidade no TSC, sem alterar a atividade locomotora no teste de campo aberto. A redução do tempo de imobilidade de 2-BFI (100 μmol/kg, s.c.) foi confirmada com o TNF. O efeito tipo-antidepressivo do 2-BFI (100 μmol/kg, s.c.) no TSC foi prevenido pelo pré-tratamento com idazoxan (0,4 μmol/kg, i.p., um antagonista do sítio I2), metisergida (4 μmol/kg, i.p., um antagonista não-seletivo dos receptores serotoninérgicos) e haloperidol (0,1 μmol/kg, i.p., um antagonista não-seletivo dos receptores dopaminérgicos). O efeito ansiolítico do 2- BFI também foi avaliado, utilizando o teste de labirinto em cruz elevado. O 2-BFI (300 μmol/kg, s.c.) aumentou significativamente a % do número de entradas e a % do tempo gasto nos braços abertos, indicando que ele possui um efeito ansiolítico em altas doses. Em conclusão, estes resultados sugerem que o efeito tipoantidepressivo de 2-BFI pode estar envolvido com os sistemas serotoninérgico, dopaminérgico e imidazolínico, e assim o sítio imidazolínico poderia representar um novo alvo farmacológico para o tratamento da depressão.