Honors Project--Smith College, Northampton, Mass., 2010.

Thesis (Ph. D.)--University of Wisconsin, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographies.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1973. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph.D.)--McMaster University, 2003. / Advisor: Michael J. McGlinchey. Includes bibliographical references (leaves 172-192). Also available via World Wide Web.

O grupo amida é encontrado em biomoléculas como as proteínas, ácidos nucleícos, bem como em polímeros sintéticos. A molécula mais simples que contém o grupamento amida é a formamida. Um grande número de estudos sobre essa molécula tem sido realizados no vácuo, no estado líquido e em solventes utilizando-se as mais diferentes técnicas experimentais e computacionais, mas ainda restam questões fundamentais sobre a sua estrutura eletrônica e solvatação. O conhecimento preciso da ressonância e das barreiras conformacionais desse composto é de fundamental importância para uma compreensão do comportamento conformacional de biomoléculas e polímeros sintéticos. Uma compreensão detalhada das interações dessa molécula com água é igualmente importante, pois o grupamento amida é um dos principais sítios de hidratação de proteínas. Este trabalho teve o objetivo de se estudar as interações existentes entre a formamida e água, nas formas de mínima energia e nos estados de transição do grupo amida, e as alterações na estrutura eletrônica da formamida. Constatou-se a existência de grandes diferenças entre a estrutura eletrônica da formamida na sua forma mais estável e a dos estados de transição da rotação do grupo amida. Através do método NBO (Natural Bond Orbitals), verificou-se uma diminuição nos efeitos de ressonância nos estados de transição provocada pela diminuição da interação entre o par de elétrons isolados do nitrogênio e o orbital 'pi' antiligante do grupo carbonila (nN→'pi'*CO). A hidratação provocou alterações na estrutura eletrônica da formamida planar e dos estados de transição. As interações intermoleculares entre formamida e água foram intensas, sobretudo nos casos em que o solvente interagiu simultaneamente com os grupos carbonila e amida. Nos estados de transição, a interação entre o par de elétrons isolado do nitrogênio da amida e a molécula de água se torna importante. As energias das ligações de hidrogênio entre a formamida e as moléculas de água são, de um modo geral, estabilizadoras das supermoléculas. Pode-se verificar que há cooperatividade apenas nas energias e não em outras propriedades. Com o auxílio das análises NBO (Natural Bond Orbitals) e NRT (Natural Resonance Theory), verificou-se um aumento da ressonância da formamida planar com a adição sucessiva de moléculas de água. Tal observação pode sugerir que as ligações de hidrogênio entre formamida e água possuem algum caráter covalente. O estudo da solvatação da formamida utilizando o modelo discreto/contínuo demonstrou que as moléculas de água explícitas exercem larga influência na energia livre de solvatação. Constatou-se a preferência pela solvatação no oxigênio do grupo carbonila e a validade do modelo discreto/contínuo. / The amide group is found in biomolecules such as proteins, nucleic acids, as well as synthetic polymers. The simplest molecule that contains the amide group is formamide. A large number of studies have been made on vacuum, liquid state and on various solvents, using the most different computational and experimental techniques, but there are many fundamental questions to be answered about its electronic structure and solvation. The precise knowledge about resonance and conformational barriers of this compound is of fundamental importance for the understanding of conformational behavior of biomolecules and synthetic polymers. A detailed understanding about the interactions of this molecule with water is equally important, for the amide group is one of the major sites of solvation in proteins. This work has the objective of studying the interactions of formamide and water, on the minimum energy conformation and the transition conformations of the amide group and the electronic structure of formamide. It has been found the existence of great differences between the electronic structure of formamide on its more stable conformation and the conformational transition states of the amide group rotation. Using the Natural Bond Orbital (NBO) analysis, a decrease of resonance effects on the transitions states was verified, due to the loss of interaction between the electrons of the nitrogen lone pair and the carbonyl 'pi' anti-bonding orbital (nN→'pi'*CO). The solvation of formamide has changed the electronic structure of planar formamide and the conformational transition states. The intermolecular interactions between planar formamide and water are very strong, specially when the solvent molecules interact simultaneously with the carbonyl and amide groups. Regarding the conformational transition states, the interaction between the nitrogen lone pairs of amide and the water molecule is observed. The hydrogen bond energies of formamide and water stabilizes the supermolecules. It can be verified that there is cooperativity only with energies and not in other properties. Using the NBO and the Natural Resonance Theory (NRT) methods, an increase of resonance for the planar form with the successive addition of water molecules has been verified. This observation suggests that the hydrogen bonds between formamide and water have some covalent character. The solvation study of formamide using the discrete/continuous model shows that the explicit waters influence the free energy of solvation. A preference for the solvation of carbonyl oxygen and the validity of the discret/continuous model has been verified.

Bonds are a type of debt securities, which are regulated by the Act on Bonds (the Act No. 190/2004 Coll., as amended). In the Czech Republic, bonds are used to finance especially the government is especially financed through bond issuing. Despite bonds are not widespread across private companies or territorial self-governing units at the moment, in the future they might play a bigger role and become a competitor to the traditional ways of financing (e.g. bank loans) thanks to their advantages. The purpose of this master's thesis is to introduce the legal regulation of bonds, to distinguish bonds from different ways of financing, including description of their advantages and disadvantages, to analyze particular requirements of bonds, to describe the process of bonds issuing and finally to divide bonds into categories according to various standpoints. The thesis is composed of five chapters. The first chapter focuses on the formal sources of Czech and European bond law and on the concept of a bond, including its characteristic features. The second chapter concerns with the comparison of bonds to other ways of financing. For purposes of this thesis a company was chosen as a role issuer for the comparison. This chapter also introduces the advantages and disadvantages of bonds in relation to theirs...

“Nanomaterials” is a generic term used to describe nano-sized crystals and bulk homogenous materials with a structural disorder at the nanoscale. Ancient (and modern) ceramics and glasses derive some of their properties (eg. pliability and low sintering temperature) from the fact that their raw material namely natural clay is nanosized. Furthermore the pigments used to colour ceramics and glasses need to have particle sizes <500 nm for the object to appear homogenously coloured to the human eye. Raman spectroscopy intrinsically probes chemical bonds and is therefore one of the few techniques that has been proven useful to provide information at the nanoscale. It is an excellent tool to study ceramics and glasses as a Raman spectrum can be used to identify phases, analyse amorphous domains in the silicate network and identify pigments on a nano-scale. The characteristics of a glass, ceramic or ceramic glaze derived through its Raman spectrum can then be linked to the technology used to produce an artefact and in this way provide information about its relative age and provenance. Likewise, the identification of pigments and binders in San rock art might provide information about production techniques and assist in the developement of conservation procedures. In this thesis micro-Raman spectroscopy (with X-ray fluorescence, X-ray powder diffraction, electronmicroscopy and photoluminescence as supportive techniques) was utilised to study archaeological artefacts from the Mapungubwe Collection and San rock art. It was possible to re-date celadon shards excavated on Mapungubwe hill in 1934 to the Yuan or even later Ming dynasty in stead of its original classification as Song. A profile of the glass technology used to produce the Mapungubwe oblates, small trade beads from the “royal burials” on Mapungubwe hill was determined and quite a few unique characteristics of the beads may eventually help to establish their provenance. The possible influence of the presence of rock hyraces at rock art sites on the deterioration of rock art were investigated and during the study very rare polymorphs of CaCO3 (vaterite and monohydrocalcite) were discovered in rock hyrax urine. This study was extended to analyse a San rock art fragment and another first was the identification of animal fat on the fragment, but the exact origin of the fat has to be verified by similar experiments. / Thesis (PhD)--University of Pretoria, 2009. / Physics / unrestricted

Molecular orbital calculations have been successively applied to mineralogical studies of equilibrium molecular geometry, electronic charge distributions, electronic spectra and bulk modulus calculations. To date, these studies have modelled bonding at atmospheric pressure. With the ever increasing interest in high pressure phases and mantle mineralogy, bonding studies of molecular groups at simulated high pressure can be an invaluable aid to understanding high pressure crystal chemistry, bond energetics and electronic spectra. This investigation tests the feasibility of various models to simulate pressure in ab initio SCF MO calculations on common metal-oxygen polyhedra. Pressure is simulated in the cluster, H₆Si₂O₇, by systematically stepping helium atoms directed^ along the Si-O bridging vectors toward the bridging oxygen. Changes in the Si-0 bond lengths, SiOSi angles and Si-0 force constants are monitored with increasing pressure. For an increase of 60 kbar pressure, the Si-0 bond length and SiOSi angle decrease 0.30% and 4.5%, respectively, which compares well with the 0.30% and 6.6% decrease observed in c-quartz for a similar increment of pressure. The linear correlation of Si-0 bond length and -sec(SiOSi), known to occur at one bar, holds at elevated pressure. In addition, the Si-0 stretching and SiOSi bending force constants show a percentage increase in the ratio 1:6 up to an estimated pressure of 140 kbar. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Given the prevalence of primary amines in biologically active molecules, an important area of research is devoted to creating methods to site-selectively functionalize their C(sp³)-H bonds. For simple aliphatic primary amines, many of these C-H bonds are chemically indistinguishable due to their similar electronics and sometimes, steric environments. Through strategic choice of activating group, site-selective functionalization at both α- and ẟ- positions is achieved. Exploiting inductive effect allows for a photoredox-catalyzed α-C(sp³)-H alkylation of trifluoromethanesulfonamides. In the case of trifluoroacetamides, functionalization is directed to a distal C(sp³)-H site via [1,5]-hydrogen atom transfer which results in a formal delta-aminomethylation and delta-cyanation. Lastly, by subjecting primary amines to an electron-rich benzaldehyde activating group, we leverage C-N bonds as a functional handle for deaminative radical cross-couplings.