Zugl.: Düsseldorf, Univ., Diss., 2007

O presente trabalho busca analisar alguns elementos estéticos presentes na criação da obra O Guesa, do poeta maranhense Joaquim de Sousa Andrade, mais conhecido como Sousândrade. Procura-se demonstrar que a forma de sua poesia não consiste apenas em um capricho da subjetividade romântica, carente de programa estético definido. A partir da liberdade das formas conquistada no romantismo, o poeta demonstra lucidez em sua criação poética, utilizando a \"reflexão\", a \"imaginação\" e a \"fragmentação\" para criar uma forma de objetivação homóloga à natureza selvagem da lenda do muísca do Guesa. Além disso, tal forma poética estabelece-se como meio de expressão de seus conflitos internos e da sua visão acerca dos conflitos sociais de sua época. / This paper seeks examine some of the aesthetic elements present in the creation of O Guesa, of maranhense poet Joaquim de Sousa Andrade, better known as Sousândrade. Looking up show that the form of his poetry not just in a romantic whim of subjectivity, lacking in aesthetic programme defined. From the freedom of forms conquered in romanticism, the poet demonstrates clarity in his poetic creation, using the \"reflection\", the \"imagination\" and the \"fragmentation\" to create a form of objetivation counterpart to the wild nature of the muísca legend of Guesa. Moreover, such a poetic establishes itself as a means of expression of their internal conflicts and their vision about the social conflicts of his time.

DNA replication is one of the most fundamental processes in all living organisms. Its semi-discontinuous nature dictates that the lagging strand is synthesized in short fragments called Okazaki fragments. In eukaryotes, each Okazaki fragment is initiated by an ~ 30-40 nucleotide-long RNA-DNA hybrid primer that is synthesized by Pol α-primase complex. To ensure genomic stability, the RNA primer has to be excised, any misincorporations by Pol α have to be corrected for and finally the resulting nick has to be sealed generating a contiguous strand. This feat is accomplished by a highly coordinated and regulated process called Okazaki fragment maturation. At the center of this process are 5’ nucleases, which are structure-specific nucleases that catalyze the incision of phosphodiester bonds one nucleotide into the 5’ end of ssDNA/dsDNA junctions. Previous structural and biochemical studies have shed some light on the mechanism of FEN1 substrate recognition, its catalysis and regulation. However, many gaps in our understanding of this remarkable nuclease still persist. Moreover, the choice between the short- and long-flap pathways is still elusive. Finally, the mechanism of the coordination among the different enzymatic activities of the polymerase, the nuclease and the ligase during Okazaki fragment maturation is still debatable. In this work, we set out to study FEN1 substrate recognition, catalysis and regulation using single molecule techniques. We show that FEN1 employs a sophisticated substrate recognition mechanism through which it actively distorts the DNA to ~100˚ bent angle. It also displays a remarkable selectivity towards its cognate substrate and avoids off-target substrate by a lock-down mechanism that commits the enzyme for catalysis on cognate substrates while promoting the dissociation of non-cognate substrates. We further characterized FEN1 reaction from substrate binding/bending to product handoff and built a comprehensive kinetic scheme that shows FEN1 releasing its product in two steps. Finally, we uncovered an unprecedented role of FEN1 in the choice between short- and long-flap pathways.

No description available.

This dissertation describes the benzylation of adenine under basic conditions, the unequivocal determination of the identity of the products of this reaction, an exploration of the effect of solvent on the reaction, a thorough computational study of the reaction mechanism and an investigation into the hydrogen-deuterium exchange reaction of the N-benzyladenine products and related compounds. The preferential sites of alkylation of adenine under basic conditions in DMSO were proven to be the N9 and N3 positions. X-ray crystal structures were obtained for both compounds. Formation of the N9-benzyladenine product is the most favoured in polar aprotic solvents, such as DMSO, and as the proportion of polar protic solvents, such as water, increases, so does the formation of the N3-benzyladenine product. Characteristic 1H NMR  chemical shifts of the purine ring protons and HMBC 1H-13C correlation NMR spectroscopy were useful tools to assign the 1H and 13C NMR spectra chemical shifts and confirm that the solution structures were the same as the isolated crystals. Simulating the SN2 mechanism for the N1-, N3-, N7- and N9-pathways computationally, employing DMSO as the simulated solvent, resulted in ambiguous results when considering the electronic energies of initial, TS and final products alone. However, a novel approach was developed (employing IQA-defined energy terms) to study fragment interactions along the reaction paths. It provided a full explanation of the reaction mechanism and yielded results which supported the N3/N9 positions of alkylation over the N1/N7 sites. The preference for the sites of alkylation occurs after the transition state, in which the N1/N7 reaction paths fail to proceed favourably to the end product, N1- and N7-benzyladenine, respectively. The N9-pathway dominates the N3-pathway at the product formation step, which corresponds to the N9- benzyladenine being the major product, as shown in Figure 1, and the N3-benzyladenine being the minor product from the benzylation of adenine. The faster rate of deuteration at the C8 position of N9-benzyladenine as compared to the deuteration rates at the C2 and the C8 of N3-benzyladenine, have shown support for a sp3 mediated mechanism and a carbene mediated mechanism of deuteration based on the “push” and “pull” mechanisms proposed for the C8 proton transfer of ATP in kinase enzymes. The deuteration of the C8 proton of 2,6-dichloropurine derivatives supports the existence of the carbene mediated mechanism since these compounds lack the amine moiety necessary for the sp3 mediated mechanism. These results demonstrate how experimentation and computation have led to greater insights into the reactivity of adenine and its derivatives. This strategy provides a useful platform for future research into adenine reaction mechanisms and the role adenine plays in kinase catalysis. / Dissertation (MSc)--University of Pretoria, 2015. / National Research Foundation (NRF) / Chemistry / MSc / Unrestricted

This thesis takes its starting point in four Stockholm locations; a self-service laundromat, a residential townhouse, a pedestrian tunnel and a public bath. They have emerged during different times but are brought together by their habitual and mundane character. They possess qualities that may not be seen at first glance, but becomes visible at a second or third viewing. The aim for this thesis has been to find what lies slightly out of sight – hidden yet visible. Through several steps of translations and fragmentation new scenarios have emerged.

Coherence is not unity alone, but rather expressing the same cause. How can I form a common expression between a diverse selection of fragments? I have treated the characters as fragments - something that is ripped out of its context and doesn’t belong to a system. They are individuals. The act of collecting characters relates to what the swedish author Torgny Lindgren says about his figures of projection. They are people and places he have encountered in real life, that made a strong impression on him. They have followed him through the years, reoccurring in his authorship in slightly different shapes. This is perhaps what I have been looking for, my own figures of projection within the field of architecture. Along the work with the characters, I have been reading A scientific autobiography by Aldo Rossi. Searching for my own figures of projection, Rossis description of his architectural practice has been to useful help. There is a clear connection between his sources of inspiration and his works, not only in physical resemblance, but also in strong ideas connecting different fragments with each other. The architectural method of this semester could be described as that of still life painting, were seemingly disparate fragments have been carefully joined together. The ambition was to make this diverse selection of characters come together in one building, forming a common voice. / Samstämighet handlar om mer än enighet, det är att uttrycka en gemensam sak. Hur kan en rad, till synes olika fragment, forma ett gemensamt uttryck? Jag har behandlat mina karaktärer som fragment - något som är ryckt ur sitt sammanhang och inte tillhör ett system. De är individer. Samlandet av karaktärer anknyter till vad Torgny Lindgren berättar om sina projektionsgestalter. Det är människor och platser som han har mött i verkliga livet,som har gjort så starkt intryck på honom att de har rotat sig i hans författarskap. Där återkommer de, i olika skepnader och olika berättelser.I mitt examensarbete har jag letat efter mina egna projektionsgestalter, i arkitekturen. Samtidigt som arbetet med karaktärerna har framskridit, har jag läst A Scientific Autobiography av Aldo Rossi.I sökandet efter mina egna projektionsgestalter, har Rossis beskrivning av hans praktik varit användbar. Det finns ett tydligt samband mellan de inspirationskällor han nämner, och hans egna verk. Inte bara i fysisk tappning, utan även i tydliga idéer, som kopplar samman fragment med varandra. Den arkitektoniska metoden denna termin kan enklast liknas vid stilleben-målning, där till synes helt olika fragment omsorgsfullt fogas samman till en väl avvägd helhet. Ambitionen var att låta karaktärerna samsas i en byggnad och förena sig i samma språk.

<p> Five pyroclastic breccia rock samples from a felsic volcanic sequence at Kakagi Lake, Northwestern Ontario, have been analysed for eight major elements using X-Ray Fluorescence to study the fragment-matrix relationships. The salic fragments represent a rhyodacitic composition and the matrices are of andesitic composition showing Fe and Mg enrichment and Si deficiency compared to the fragment. </p> <p> Four matrix and four fragment samples were obtained from one rock,and a triplicate analysis of one of these matrices,compared to the average of the four matrices, showed that the variability of the composition throughout the rock was not due to the analytical procedure. </p> <p> These results agree reasonably well with the trends found in previous work by Goodwin (1968) and Baragar and Goodwin (1969) considering the matrices only. The fragment-matrix study for this area is unique and has been carried out in conjunction with Smith (1971). </p> / Thesis / Bachelor of Science (BSc)

The mass spectra of some monomethylquinolines, dimethylquinolines, monoethylquinolines and monopropylquinolines have been determined. In addition, the spectra of 1,2,3,4-tetrahydroquinoline, 5,6,7,8-tetrahydroquinoline and some monomethyl-1,2,3,4-tetrahydroquinolines have also been studied. Fragmentation mechanisms are proposed to account for the most important peaks in the spectra of these compounds. Deuterium labelled analogues of many of the compounds have been prepared and their spectra support the proposed fragmentation mechanisms. / Thesis / Doctor of Philosophy (PhD)

No description available.