3 resultados para experimental chemistry

em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland


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The thesis focuses on the water chemistry of the experimental test facilities and their reference VVER reactors. The main objective of the thesis is to provide recommendations for water chemistry management for laboratory facilities (VEERA, PACTEL) simulating the VVERs and for the large future facilities of the Lappeenranta University of Technology. In the beginning, the concept of nuclear power generation and the applicability of the nuclear power usage is discussed. Next, different water chemistry and water purification systems in primary and secondary circuits currently used at the power plant have been outlined. Also the construction geometry and design of test facilities PACTEL and VEERA, as well as the operation principles of their main equipment has been described. Finally, the appropriate water chemistry and water treatment system have been proposed for the existing and future experimental facilities of LUT.

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Carbohydrates are one of the most abundant classes of biomolecules on earth. In the initial stages of research on carbohydrates much effort was focused on investigation and determination of the structural aspects and complex nature of individual monosaccharides. Later on, development of protective group strategies and methods for oligosaccharide synthesis became the main topics of research. Today, the methodologies developed early on are being utilized in the production of carbohydrates for biological screening events. This multidisciplinary approach has generated the new discipline of glycobiology which focuses on research related to the appearance and biological significance of carbohydrates. In more detail, studies in glycobiology have revealed the essential roles of carbohydrates in cell-cell interactions, biological recognition events, protein folding, cell growth and tumor cell metastasis. As a result of these studies, carbohydrate derived diagnostic and therapeutic agents are likely to be of growing interest in the future. In this doctoral thesis, a journey through the fundamentals of carbohydrate synthesis is presented. The research conducted on this journey was neither limited to the study of any particular phenomena nor to the addressing of a single synthetic challenge. Instead, the focus was deliberately shifted from time to time in order to broaden the scope of the thesis, to continue the learning process and to explore new areas of carbohydrate research. Throughout the work, several previously reported synthetic protocols, especially procedures related to glycosylation reactions and protective group manipulations, were evaluated, modified and utilized or rejected. The synthetic molecules targeted within this thesis were either required for biological evaluations or utilized to study phenomena occuring in larger molecules. In addition, much effort was invested in the complete structural characterization of the synthesized compounds by a combination of NMR spectroscopic techniques and spectral simulations with the PERCH-software. This thesis provides the basics of working with carbohydrate chemistry. In more detail, synthetic strategies and experimental procedures for many different reactions and guidelines for the NMR-spectroscopic characterization of oligosaccharides and glycoconjugates are provided. Therefore, the thesis should prove valuable to researchers starting their own journeys in the ever expanding field of carbohydrate chemistry.

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This thesis is based on computational chemistry studies on lignans, focusing on the naturally occurring lignan hydroxymatairesinol (HMR) (Papers I II) and on TADDOL-like conidendrin-based chiral 1,4-diol ligands (LIGNOLs) (Papers III V). A complete quantum chemical conformational analysis on HMR was previously conducted by Dr. Antti Taskinen. In the works reported in this thesis, HMR was further studied by classical molecular dynamics (MD) simulations in aqueous solution including torsional angle analysis, quantum chemical solvation e ect study by the COnductorlike Screening MOdel (COSMO), and hydrogen bond analysis (Paper I), as well as from a catalytic point of view including protonation and deprotonation studies at di erent levels of theory (Paper II). The computational LIGNOL studies in this thesis constitute a multi-level deterministic structural optimization of the following molecules: 1,1-diphenyl (2Ph), two diastereomers of 1,1,4-triphenyl (3PhR, 3PhS), 1,1,4,4-tetraphenyl (4Ph) and 1,1,4,4-tetramethyl (4Met) 1,4-diol (Paper IV) and a conformational solvation study applying MD and COSMO (Paper V). Furthermore, a computational study on hemiketals in connection with problems in the experimental work by Docent Patrik Eklund's group synthesizing the LIGNOLs based on natural products starting from HMR, is shortly described (Paper III).