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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Optimization of in vitro transcription/translation conditions for in vitro compartmentalization studies and synthesis of 4-fluorohistidine

Ring, Christine 01 January 2017 (has links)
Genetic code expansion allows the incorporation of non-canonical amino acids with a variety of new functional groups: fluorescent amino acids,1-3 azides,4-6 alkynes,5-10 and photocrosslinkers.4,11,12 This incorporation requires the evolution of new tRNA/aminoacyl tRNA sythetase pairs. Traditionally screenings of novel tRNA/aminoacyl tRNA synthetase pairs have been done in vivo. While these in vivo screenings have proven robust, they are limited in multiple ways: non-canonical amino acids (ncAAs) must be nontoxic and bioavailable. Furthermore, library size is limited by transformation efficiency. Lastly, in vivo screenings require substantial amounts of the target ncAA, which is often not available in large masses. In vitro screenings bypass these limitations: toxicity and bioavailibilty are no longer concerns. Library size can be expanded by several orders of magnitude as we are no longer limited by transformation efficiency. Lastly, because in vitro transcription/translation reactions are routinely conducted on the μL scale, ncAA usage can be minimized. We set out to use in vitro compartmentalization to further expand the code. In an in vitro compartmentalization screening, the water droplets in a water-in-oil emulsion serve as separate reaction chambers in which individual library members are transcribed and translated. Here we report optimization of S30 transcription/translation reactions. Optimizations include cell lysis method, reaction temperature, template amount, and T7 RNA polymerase amounts. Yields remained low and we transistioned into the use of PURExpress. Fluorohistidines are isosteric with histidine, but not isoelectronic.13 This change in environment results in a reduction of pKa. We set out to synthesize 4-fluorohistidine to use as a pH probe in several target proteins. A synthesis of 4-fluorohistidine was published in 1973.14,15 We were able to improve upon this synthesis by reducing cost and improving yield of a key step in the reaction. Next, small peptides with polyhistidine tags were translated in vitro using our 4-fluorohistidine. We are calling this polyhistidine tag incorporating 4-fluorohistidine our “hexafluorohistag.” Because of the reduced pKa of the 4-fluorohistidine, the hexafluorohistag showed affinity to Nickel-NTA resin even at reduced pH. This allowed for the purification of hexafluorohistagged peptides in the presence of traditional polyhistidine-tagged peptides.
2

Hur påverkas aktiemarknaden av räntan, valuta- och obligationsmarknaden? : En empirisk studie under perioden 2005-2009

Agaev, Orhan, Basit, Husnain January 2010 (has links)
<p><strong>Introduction:</strong> Interplay between all the different subsystems of the financial markets is currently considered as an important internal force in the market. In a financially liberalized economy exchange rate stability is a basis for a wellbeing stock market. If these interactions between all the different subsystems of the financial markets are not detected, this means that there is information inefficiency in the markets.</p><p><strong>Problem:</strong> Can we find any correlation between changes in currency, interest rate and bonds with the stock market index? If so, how do these changes affect the Stockholm Stock Exchange?</p><p><strong>Purpose:</strong> The purpose of this study is to examine if there is any linkage between the interest rate, currency and bonds with the stock market. The researchers wanted to find out how these variables affect the stock market index OMX S30 which consists of the 30 largest companies on the Stockholm Stock Exchange.</p><p><strong>Method:</strong> This research has been based on a quantitative approach. Three variables were selected to determine their possible linkage with the stock market index. We have collected the quantitative data from the CMC Markets and Swedish central bank in order to obtain the necessary statistical information. We have then examined the information in SPSS and Excel.</p><p><strong>Empirical and analytical:</strong> The result shows that the government bonds which are one of the independent variables are significant explanatory variable for OMX S30. Interest rate contributes significantly to the model and is a significant explanatory variable for stock market. However, the currency has a weak contribution to the model which means that the currency is not a significant explanatory variable for OMX S30.</p>
3

Hur påverkas aktiemarknaden av räntan, valuta- och obligationsmarknaden? : En empirisk studie under perioden 2005-2009

Agaev, Orhan, Basit, Husnain January 2010 (has links)
Introduction: Interplay between all the different subsystems of the financial markets is currently considered as an important internal force in the market. In a financially liberalized economy exchange rate stability is a basis for a wellbeing stock market. If these interactions between all the different subsystems of the financial markets are not detected, this means that there is information inefficiency in the markets. Problem: Can we find any correlation between changes in currency, interest rate and bonds with the stock market index? If so, how do these changes affect the Stockholm Stock Exchange? Purpose: The purpose of this study is to examine if there is any linkage between the interest rate, currency and bonds with the stock market. The researchers wanted to find out how these variables affect the stock market index OMX S30 which consists of the 30 largest companies on the Stockholm Stock Exchange. Method: This research has been based on a quantitative approach. Three variables were selected to determine their possible linkage with the stock market index. We have collected the quantitative data from the CMC Markets and Swedish central bank in order to obtain the necessary statistical information. We have then examined the information in SPSS and Excel. Empirical and analytical: The result shows that the government bonds which are one of the independent variables are significant explanatory variable for OMX S30. Interest rate contributes significantly to the model and is a significant explanatory variable for stock market. However, the currency has a weak contribution to the model which means that the currency is not a significant explanatory variable for OMX S30.

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