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Antioxidant activity of cyclolinopeptides2013 June 1900 (has links)
Cyclolinopeptides (CLs) are hydrophobic cyclic peptides found in flaxseed. They show immunosuppressive activity, but the biological function of these compounds is largely unknown. This thesis presents the results of studies that were conducted to determine whether CLs could act as antioxidants. In the first study, flaxseed oil was passed over a silica adsorbent column to remove polar compounds. The polar compounds were then eluted from the silica absorbant using a series of increasingly polar solvents. Individual polar fractions were then added back to the silica-treated flaxseed oil and the oxidative stability index of these samples was determined at 100 °C. A polar fraction containing mainly CLA, β/γ- and δ-tocopherol increased the induction time of silica-treated flaxseed oil from 2.3 ± 0.28 h to 3.2 ± 0.41 h. A positive effect of the polar fraction containing a mixture of CLA and CLD-CLG on the oxidative stability of oil was also observed. The antioxidant mechanism of CLs was investigated in several model systems using electron spin resonance spectroscopy. The concentration of radicals in a DMPO (5,5-dimethyl-1-pyrroline-N-oxide) radical-CLs reaction mixture was monitored. All CLs exhibited dose dependent scavenging activities. CLA–CLC reactions with DMPO-OH at a concentration of 5 mM resulted in a 24–30% decrease in electron paramagnetic resonance (EPR) signal intensity. The reaction of CLs and the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH•) revealed a more complex interaction than simple radical scavenging. Peptides (CLG and CLG") that contained both tryptophan and methionine showed stronger radical scavenging activity than did CLs containing methionine or methionine sulfoxide but not tryptophan (CLB and CLC). Irradiation of the reaction mixture of DPPH• and peptide with UV light also affected the radical scavenging behaviour. Scavenging activities of DPPH• by CLB, CLC and CLA were enhanced by light, whereas scavenging of DPPH• by the tryptophan containing peptides CLG and CLG″ was not affected. High-performance liquid chromatography with mass spectrometry (HPLC-MS) analysis of the reaction mixtures after a radical scavenging reaction was used to determine the impact of radical scavenging on the peptides. These reactions revealed new masses that were identified and characterized. It was established that DPPH• reacted with the methionine of CLB and with tryptophan in CLG and CLG, by formation of a new covalently-bonded species. Covalent linkages between these amino acids (alone or in peptides) and DPPH• have not been reported previously.
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Gender Representation in the Media : A Critical Analysis of the Construction of Female Sexuality in Men's Pornographic and Non-Pornographic MagazinesTognela, Jennifer 29 March 2011 (has links)
This thesis applies the radical feminist perspective set out by MacKinnon (1993) and Dworkin (1995), to analyze the construction of female sexuality within popular Canadian men’s pornographic magazines and non-pornographic magazines. A mixed methods approach was used to analyze the images and text within the feature articles of the selected magazines. Results revealed that women continue to be constructed as sexual objects within both categories of magazines, but the earlier link identified by MacKinnon and Dworkin between violence and sexuality was on longer apparent. Instead, women were a sexual puzzle that the magazines attempted to unpack. Rather than a strict dichotomy between pornographic and non-pornographic magazines, a continuum of grey emerged whereby the level of explicitness between the two magazines increased as the continuum progressed from left to right, thereby demonstrating the pornographication of mainstream media, as per McNair (2002).
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Interactions of Metals and Radicals: A Biochemical Perspective in Tryptophan DioxygenaseDornevil, Kednerlin 07 July 2011 (has links)
An intriguing mystery about tryptophan 2, 3-dioxygenase is its hydrogen peroxide-triggered enzyme reactivation from the resting ferric oxidation state to the catalytically active ferrous form. In this study, we found that such an odd Fe(III) reduction by an oxidant depends on the presence of L-Trp, which ultimately serves as the reductant for the enzyme. In the peroxide reaction with tryptophan 2, 3-dioxygenase, a previously unknown catalase-like activity was detected. A ferryl species (δ = 0.055 mm/s and ΔEQ = 1.755 mm/s) and a protein-based free radical (g = 2.0028 and 1.72 millitesla linewidth) were characterized by Mössbauer and EPR spectroscopy, respectively. This is the first compound ES-type of ferryl intermediate from a heme-based dioxygenase characterized by EPR and Mössbauer spectroscopy. Density functional theory calculations revealed the contribution of secondary ligand sphere to the spectroscopic properties of the ferryl species. A Trp-Trp dimer and a monooxygenated L-Trp were both observed as the enzyme reactivation by-products by mass spectrometry. Together, these results lead to the unraveling of an over 60-year old mystery of peroxide reactivation mechanism.
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Gender Representation in the Media : A Critical Analysis of the Construction of Female Sexuality in Men's Pornographic and Non-Pornographic MagazinesTognela, Jennifer 29 March 2011 (has links)
This thesis applies the radical feminist perspective set out by MacKinnon (1993) and Dworkin (1995), to analyze the construction of female sexuality within popular Canadian men’s pornographic magazines and non-pornographic magazines. A mixed methods approach was used to analyze the images and text within the feature articles of the selected magazines. Results revealed that women continue to be constructed as sexual objects within both categories of magazines, but the earlier link identified by MacKinnon and Dworkin between violence and sexuality was on longer apparent. Instead, women were a sexual puzzle that the magazines attempted to unpack. Rather than a strict dichotomy between pornographic and non-pornographic magazines, a continuum of grey emerged whereby the level of explicitness between the two magazines increased as the continuum progressed from left to right, thereby demonstrating the pornographication of mainstream media, as per McNair (2002).
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Investigation of Kinetics of Nitroxide Mediated Radical Polymerization of Styrene with a Unimolecular InitiatorZhou, Mingxiao January 2009 (has links)
This thesis presents the results of a study on the kinetics of nitroxide-mediated radical polymerization of styrene with a unimolecular initiator. The primary objective was to obtain a more comprehensive understanding of how a unimolecular-initiating system controls the polymerization process and to clarify the effects of various reaction parameters.
Previous work in this field has met with some difficulties in the initiator synthesis, such as low yield and inconsistency of molecular weight. These problems were overcome by adjusting reaction conditions and procedures. Better yields of initiator with consistent molecular weight were produced by the improved methods.
Control of polymerization rate and polymer molecular weight in unimolecular nitroxide-mediated radical polymerization was studied by looking at the effects of the three main factors: initiator concentration, temperature, and the initiator molecular weight on polymerization rate, molecular weight and polydispersity. Results indicated that increasing the initiator concentration had no effect on polymerization rate at low conversion, but led to lower polymerization rate at high conversion; higher initiator concentration led to lower molecular weight of the resulting polymer. It was also found that temperature significantly increased the polymerization rate, yet had no effect on number-average molecular weight, Mn, at low conversion, while it caused a plateau at high conversion levels; there was no effect on weight-average molecular weight, Mw, through the whole conversion range. In addition, increasing initiator molecular weight was found to have no effect on either polymerization rate or molecular weight.
The experimental molecular weights of the unimolecular system were compared to theoretical molecular weights based on ideal controlled radical polymerization (CRP). The results were found to be close to the theoretical values. This confirmed the advantages of the unimolecular system, namely, the degree of control over molecular weight was nearly ideal (for certain conditions); and molecular weights could thus be predicted by simply following general rules relating to CRP mechanisms.
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Balthasar Hubmaier's Sword: A Circumstantial DevelopmentWiens, Rudolph Henry January 2010 (has links)
The sixteenth century Bavarian Anabaptist, Balthasar Hubmaier (ca. 1480-1528), has had a disputed role in Anabaptist historiography ever since his martyrdom in March, 1528. On the one hand he is known as the most erudite and prolific writer of the early Anabaptists, and on the other he has been separated from the original Zurich Brethren by his rejection of two major principles, total separation from the world and absolute non-resistance, that were supposedly held unanimously by the Zurich Brethren. Today Hubmaier’s reputation for militancy has been endorsed by most writers, but this militancy is not expressed in any of his writings except On the Sword, the last tract written before his death. Using the well-documented biography of Hubmaier by Bergsten and his own writings collected and translated by Pipkin and Yoder, the thesis explores the question of the extent to which Hubmaier was willing to advocate the use of lethal force by government or against government. It is found that only one source, Johann Faber, accused Hubmaier of inciting peasant revolt , and that witness would seem dubious by any modern standard. Arguments that Hubmaier was ostracized by the Zurich Brethren are found to be conjectural and dependent upon anachronism. Thus in the critical years 1524-26, Hubmaier was a veritable Swiss Brethren. On the Sword indicates a major change in Hubmaier’s thinking, and the reasons for that change are explored.
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Designing Innovation of Meanings - A Competitive AdvantageMagnusson, Jonas, Nilsson, Johan January 2011 (has links)
Design is a resource that could be better utilized by companies in order to create growth and sustainable innovation in the future. Numerous scholars have therefore stressed the importance of forward-looking executives and designers in today’s organizations that realize the importance of design as a differentiator. This research intends to illustrate how innovation of meanings is a future competitive advantage and to show how companies can benefit from design as an innovation tool. New product meanings can be pushed upon the market through proposals, something that is being compared to the traditional user-centred methods where user needs are being scrutinized. The theoretical framework identifies four factors that can be set in relation to any company in order to investigate its stance towards innovation of new meanings. The research is limited to focus on two case companies and complemented by information from Jönköping School of Engineering, being their mutual external source of novel design ideas. The case studies show how the four factors all rely on a vision that supports design and affects the firms’ ability to capitalize on novel ideas found among external sources. This study concludes that a co-occurring search of novel design interpretations and market pull innovations is of highest importance. It further discusses how to interact with external sources in a way that does not block their potential to explore new product meanings.
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Analyses of the Production System Development Process in Manufacturing Industries - A Comparative Analysis study on Manufacturing Industries in Sweden and IndiaRanganathan, Nandakumar January 2012 (has links)
In the competitive world of manufacturing, the companies would like to produce their products at reduced price and superior quality. In the production system, the company faces many problems during the production of their products. Over the past years the manufacturing industry follows suitable techniques in their production system for the improvements in production. Still, companies are in search for new technology or techniques to improve their production in radical ways during a short period of time. Many researchers have discussed the development of production system through continuous improvements. Techniques like lean, kaizen etc are implemented in the production system but the effect of these techniques is realized in production unit only after many years. Kaikaku is another technique in lean production which occurs in a radical way to eliminate waste to provide a greater value. It is a radical process improvement which takes place in short period of time. Kaikaku is normally used when Kaizen techniques are not providing enough positive results to keep an organization effective. Still, radical improvements often need capital investment. It is often focused on introducing new technology, new strategies, or completely new production system. This main objective of this thesis is to understand and analyze the production system development process in manufacturing industries and suggest how it is effective to keep an organization competitive. The basic conception and research aid of various authors are explained in the theoretical framework, and is done for the enhanced understanding of the reader and also a new conceptual theory structure framework is done to introduce the new concept of process innovation for radical improvements in the company. The proposed structure framework can help companies to practice the process innovation in the production system for development in short period of time. Based on the conceptual structure and relevant theoretical understandings, the interview questions are framed and case companies are analyzed for the process improvements and process innovation performance in the production system. The empirical data is collected from case companies through interviews. With the help of empirical results and the related theoretical results, an analysis and discussion is made which clearly explains about the problems faced in the production system and how they can be solved through in a radical way.
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Memory, Modernity, and the City: An Interpretive Analysis of Montreal and Toronto's Respective Moves From Their Historic Professional Hockey ArenasGunderson, Lisa January 2004 (has links)
This thesis seeks to understand how and if the popular claims that hockey is an integral part of the culture in Toronto and Montreal are referenced, oriented to, and/or negotiated in everyday life. Taking the cases of the moves of the Toronto Maple Leafs and the Montreal Canadiens from Maple Leaf Gardens and the Montreal Forum, respectively, the thesis asks: What can these similar cases tell us about the culture of the cities in which they occurred and, if it is possible, in what ways can the culture of the cities (as a shaping force) be made recognizable in the discourse generated in, around, and by the moves? The perspective taken is a 'radical interpretive' approach, involving a critical blend of interpretive theories and methodologies - including semiology, phenomenology, hermeneutics, and dialectical analysis - that aim to reflexively question the themes that the cases themselves bring to light. The thesis thus concerns itself with issues of cosmopolitanism, globalization, and modernity as well as the concomitant questions of identify, commitment to place, and practical social action in the modern city.
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Investigation of Kinetics of Nitroxide Mediated Radical Polymerization of Styrene with a Unimolecular InitiatorZhou, Mingxiao January 2009 (has links)
This thesis presents the results of a study on the kinetics of nitroxide-mediated radical polymerization of styrene with a unimolecular initiator. The primary objective was to obtain a more comprehensive understanding of how a unimolecular-initiating system controls the polymerization process and to clarify the effects of various reaction parameters.
Previous work in this field has met with some difficulties in the initiator synthesis, such as low yield and inconsistency of molecular weight. These problems were overcome by adjusting reaction conditions and procedures. Better yields of initiator with consistent molecular weight were produced by the improved methods.
Control of polymerization rate and polymer molecular weight in unimolecular nitroxide-mediated radical polymerization was studied by looking at the effects of the three main factors: initiator concentration, temperature, and the initiator molecular weight on polymerization rate, molecular weight and polydispersity. Results indicated that increasing the initiator concentration had no effect on polymerization rate at low conversion, but led to lower polymerization rate at high conversion; higher initiator concentration led to lower molecular weight of the resulting polymer. It was also found that temperature significantly increased the polymerization rate, yet had no effect on number-average molecular weight, Mn, at low conversion, while it caused a plateau at high conversion levels; there was no effect on weight-average molecular weight, Mw, through the whole conversion range. In addition, increasing initiator molecular weight was found to have no effect on either polymerization rate or molecular weight.
The experimental molecular weights of the unimolecular system were compared to theoretical molecular weights based on ideal controlled radical polymerization (CRP). The results were found to be close to the theoretical values. This confirmed the advantages of the unimolecular system, namely, the degree of control over molecular weight was nearly ideal (for certain conditions); and molecular weights could thus be predicted by simply following general rules relating to CRP mechanisms.
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