Physics, General

The specificity of the conotoxin is one of the attributes that make them a valuable diagnostic tool in the characterization of neuronal mechanisms, or therapeutic agents in medicine. It appears that Nature has provided us with a pharmaceutical tool in the form of Conus peptides. Further studies will only enhance our understanding, and use, of these molecules in medicine and science. The study of three-dimensional structure in relation to the function of cone snail peptides is an area of increasing interest. The venom of a single cone snail can contain as many as 300 different chemical components. Individual cone snail venom components, or conopeptides, can have powerful neurological effects. For many interesting species, not enough venom collected from the natural origin is available for experimental investigations. After a laborious separation procedure, only nanomole quantities of these native conopeptides are able to be obtained. Therefore, several experimental applications, such as NMR spectroscopy, are difficult to carry out using traditional methods. The research was focused on using nanoNMR spectroscopy as an alternative method to the conventional NMR spectroscopy method in order to analyze small quantities of novel peptides with unknown three-dimensional conformational arrangement. The experimental results obtained using the HR-MAS NMR technique, in addition to the use of a 3mm gHCN (with 1.7mm inserts) NMR probes, proved the capability of conformational analysis of different types of natural products at sample levels down to nanomole range. Understanding the interaction between agonist or antagonist ligands and their target receptors, at a molecular level, offer promise for the development of pharmacological therapeutics for the central nervous system. Conopeptides are of great interest as ligands in neuroscience and are valuable leads in drug design, based on their specificity and potency for therapeutically relevant receptors and ion channels. For instance, the compound called Prialt (formerly known as Ziconotide), a synthetic form of a cone snail-derived peptide, is the most powerful painkiller known and has already received the Food and Drug Administration (FDA) approval. The drug is part of a new class known as the N-type calcium channel blockers, which are responsible for transmitting pain signals. Several related cone snail drugs are currently in clinical trials and could eventually be used to treat different diseases such as Alzheimer's, epilepsy and Parkinson's.

Perhaps constructing a complete theory of quantum gravity, has been one of the greatest challenges for theoretical physicists in the last few decades, a theory that would reconcile general relativity and quantum mechanics. Addressing this issue, we are drawing a parallel between the Schrodinger and Klein-Gordon equation in quantum mechanics and Schrodinger-based or Klein-Gordon based wave equation in canonical quantum gravity. In particular we analyze the quantum geometrodynamics Schrodinger equation for a homogeneous cosmological model and we study the quantum field effects for the &PHgr;6 scalar field in Kantowski-Sachs universe. In essence, we present a unified view of quantum gravity by establishing a parallel between our study and the usual quantum mechanics. Thus, the first part of this dissertation deals with the quantization of Bianchi type IX space-time where the concept of time is derived by imposing the constraints as expectation values over the true dynamical-degrees of freedom of the gravitational field. Thus, we obtained a Schrodinger type wave equation instead of the Wheeler-DeWitt which is associated with the problem of time in quantum gravity [1]. The main technical difference between our proposed equation and other quantum cosmology approaches is in our treatment of the constraints. Ordinarily, the equation cannot be solved simply by separating the coordinates variables, and only under some specific conditions imposed on the background that one may obtain exact analytical expressions. In the second part, we evaluated the one-loop renormalized effective potential for the massive self interacting &PHgr;6 theory the spatially homogenous and anisotropic Kantowki-Sachs Universe. We concluded that regularizing the theory in (3 + 1) dimensional space-time may not be possible. Finally, we looked at the time evolution of the critical temperature that is associated with our model.