Sökning: "pyrimidine"

Visar resultat 1 - 5 av 53 avhandlingar innehållade ordet pyrimidine.

1. 1. Physicochemical and Structural Aspects of Nucleic Acids

   Författare :Subhrangsu Chatterjee; Adolf Gogoll; Helena Grennberg; Göran Widmalm; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; pKa; Hydrogen bonding; Stacking; NMR; MD; DNA; RNA; Pyrimidine; Organisk kemi;

   Sammanfattning : This thesis consists of seven research publications concerning (i) pKa studies of nucleobases in model nucleotides to understand why RNA duplexes are more stable than DNA duplexes (Paper I), (ii) the role of Me(T)-π interactions in the relative stability of DNA-RNA heteroduplexes (Paper II), (iii) pKa measurements in nucleotides with different 2′-substituents (paper III), (iv) a conformation study of constrained sugars and a pKa study of 1-thyminyl to reveal effect of sugar constraints on the pKa of the nucleobase (paper IV), (v) NMR and MD studies of 1′, 2′-oxetane constrained thymidine incorporated Dickerson Drew dodecamer (paper V), (vi) the sequence dependent pKa perturbation of 9-guaninyl moeity in single stranded (ss) DNA and RNA (paper VI), (vii) the non identical chemical nature of internucleotidic phosphates in (ss) RNA using 31P NMR (paper VI), and an alkaline hydrolysis study of phosphodiesters in ssRNAs (paper VII). The architecture of DNA and RNA molecules is determined by (a) hydrogen bonding (b) base stacking (c) a variety of additional non-covalent interactions. LÄS MER

3. 2. Multiconfigurational perturbation theory

   Författare :Kerstin Andersson; Karlstads universitet; []
   Nyckelord :Electron correlation; CASSCF; multiconfigurational second-order perturbation theory; CASPT2; ozone; C; N; O; F; Si; P; S; Cl; Ni; benzene; pyridine; pyrazine; pyrimidine; pyridazine; s-triazine; electric properties; excited states; spectroscopic data;

   Sammanfattning : The aim of the thesis is to analyze a method which describes the electron correlation in atoms and molecules. The method is based on Rayleigh-Schrödinger perturbation theory with a partitioning of the Hamiltonian into a fairly simple zeroth-order operator and a perturbation operator. LÄS MER

4. 3. New methods for the synthesis of N-heteroaromatics and imines

   Författare :Kenji Kopf; Belén Martín Matute; Joseph P. A. Harrity; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; heterocyclic; heteroaromatic; atropisomer; pyridine; pyrimidine; MOF; amine coupling; catalysis; benzannulation; organisk kemi; Organic Chemistry;

   Sammanfattning : This thesis is divided in four chapters, containing the work realised in two universities and has as the aim the synthesis of nitrogen-containing compounds. The first chapter describes the project realised at The University of Sheffield. LÄS MER

5. 4. Vascular Effects of P2 Receptors. Changes in Congestive Heart Failure

   Författare :Malin Malmsjö; Lund Medicin; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; congestive heart failure; pyrimidine; purine; P2 receptor; vasodilatation; vasoconstriction; hyperpolarisation; EDHF; NO; Vascular; endothelium; Cardiovascular system; Kardiovaskulära systemet;

   Sammanfattning : Extracellular nucleotides induce dilatation and constriction of blood vessels by activation of P2 receptors. In this thesis the vasomotor effects of P2 receptor activation were studied in the rat mesenteric artery, and their changes in congestive heart failure (CHF) were evaluated using in vitro pharmacology, electrophysiology and competitive RT-PCR. LÄS MER

7. 5. Structure Function Relationships in Pyrimidine Degrading and Biocatalytic Enzymes, and Their Implications for Cancer Therapy and Green Chemistry

   Författare :Dirk Maurer; Doreen Dobritzsch; Mikael Widersten; Rikkert Wierenga; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; β-Ureidopropionase; Dihydropyrimidine Dehydrogenase; Alcohol Dehydrogenase; Pyrimidine catabolism; 5-Fluorouracil; CASTing; X-ray Crystallography;

   Sammanfattning : This thesis includes the work of two separate projects, studies on pyrimidine degrading enzymes and studies on in vitro evolved enzymes. The common denominator of both projects was the use of structural information to explain functional effects, observed in the studied biocatalysts. LÄS MER