Computational chemistry studies of UV induced processes in human skin

This thesis presents and uses the techniques of computational chemistry to explore two different processes induced in human skin by ultraviolet light. The first is the transformation of urocanic acid into a immunosuppressing agent, and the other is the enzymatic action of the 8-oxoguanine glycosylase enzyme. The photochemistry of urocanic acid is investigated by time-dependent density functional theory. Vertical absorption spectra of the molecule in different forms and environments is assigned and candidate states for the photochemistry at different wavelengths are identified. Molecular dynamics simulations of urocanic acid in gas phase and aqueous solution reveals considerable flexibility under experimental conditions, particularly for for the cis isomer where competition between intra- and inter-molecular interactions increases flexibility. A model to explain the observed gas phase photochemistry of urocanic acid is developed and it is shown that a reinterpretation in terms of a mixture between isomers significantly enhances the agreement between theory and experiment , and resolves several peculiarities in the spectrum. A model for the photochemistry in the aqueous phase of urocanic acid is then developed, in which two excited states governs the efficiency of photoisomerization. The point of entrance into a conical intersection seam is shown to explain the wavelength dependence of photoisomerization quantum yield. Finally some mechanistic aspects of the DNA repair enzyme 8-oxoguanine glycosylase is investigated with density functional theory. It is found that the critical amino acid of the active site can provide catalytic power in several different manners, and that a recent proposal involving a SN1 type of mechanism seems the most efficient one.

Illuminating Inner Life : A Comparison of Virginia Woolf's To the Lighthouse and Arthur Schnitzler's Fräulein Else

In the early 20th century, authors increasingly experimented with literary techniques striving towards two common aims: to illumine the inner life of their protagonists and to diverge from conventional forms of literary representations of reality. This shared endeavour was sparked by changes in society: industrialisation, developments in psychology, and the gradual decay of empires, such as the Victorian (1837–1901) and the Austro-Hungarian (1867–1918). Those developments yielded a sense of uncertainty and disorientation, which led to a so-called “turn [inwards]” in the arts (Micale 2). In this context, this essay examines Virginia Woolf’s (1882–1941) development of her literary technique by comparing To the Lighthouse (1927), written in free indirect discourse, with Arthur Schnitzler’s (1862–1932) Fräulein Else (1924), written in interior monologue. Instead of applying Freud’s theories of consciousness, I will demonstrate how empiricist psychology informed and partly helped shape the two narrative techniques by referring to Ernst Mach’s (1838–1916) idea of the unstable self, and William James’ (1842–1910) concept of the stream of consciousness. Furthermore, I will show that there is a continuous progression of literary ideas from Schnitzler’s Viennese fin-de-siècle connected to impressionism, towards Woolf’s Bloomsbury aesthetics connected to Paul Cézanne’s post-impressionist logic of sensations. In addition to that, I address how the women’s movement, starting in the end of the 19th century, inspired Woolf and Schnitzler to utilise their techniques as a means of revealing women’s restricted position in society. Methodologically, I will analyse the two novels’ narrative techniques applying close reading and by that point out their differences and similarities in connection to the above-mentioned theories as well as the two author’s literary approaches. I argue that this comparison demonstrates that modernist literary techniques of representing interiority evolved from interior monologue towards free indirect discourse. This progression also implicates that modernism can be seen as a continuum reaching back to the fin-de-siècle and culminating in the 1920s.