Surface gradients are materials that exhibit a variation in properties such as chemical composition, topography etc., in a continuous and/or discrete fashion. They are broadly classified as chemical and physical gradients depending upon the properties that gradient exhibits. Among those, chemical gradients on various surfaces have been a great interest in materials research for the last two decades. This is due to the applications of gradients in various fields such as biological sciences, separation science, etc. There have been several different approaches developed for the preparation of chemical gradients. Silane-based approaches are among those that are widely used because of the straightforwardness of the chemistry involved and also the availability of silanes with various chemical functionalities. A few of these silane based approaches such as the vapor-diffusion method and liquid diffusion method have been used for various applications so far. Most of these methods were only able to prepare surface chemical gradients for a specific application mainly because of their limitations in terms of gradient-length scale and chemistry involved. Hence, there is a need to develop additional procedures for the preparation of chemical gradients that can be adaptable to different substrates and use them to form gradients at various length-scales such as few hundred microns to tens of centimeters. Using 3-aminopropyltriethoxysilane (APTEOS) as the precursor, a simple method was developed to prepare surface amine gradients termed ‘controlled-rate infusion (CRI). The CRI method involves the infusion of an organoalkoxysilane solution into a container with a substrate mounted vertically so that time-based exposure along the substrate forms a gradient in chemical functionality. The most important attribute of this method is that the local steepness of the gradient can be systematically controlled by simply changing the rate of infusion. The steepness of the gradient can also be changed at predefined positions along its length by programming the rate of infusion. The ability to manipulate the gradient profile is particularly important for applications that rely on mass transport and/or those that require spatial control of gradient properties. CRI can also be used to study the reactivity of aminoalkoxysilanes that contain mono, di and tri amino groups and also amines with various substitutions (secondary and tertiary amines). The gradient profiles in each case were different and correlated to their reactivity with surface silanols. Among those aminoalkoxysilanes, ethylenediamine and diethlenetriamine were found to be very good chelating agents to bind with metal ions. Thus, gradients prepared with diamine and triamine were used as ligand density gradients for the investigation of metal-amine complex formation using two different metal ions (Cu2+ and Zn2+). The above mentioned work formed the first part of this dissertation (up to Chapter 5). The latter part concentrates on fabrication and application of surface gradients for stationary phases for chromatographic separation. For the demonstration of proof-of-principle of the application of gradient stationary phases, the CRI approach was employed to prepare continuous stationary phase gradients on HP-TLC plates for planar chromatography. The SiOH groups on the activated HP-TLC plates were reacted with 3-aminopropyltriethoxysilane (APTEOS) in a time dependent fashion by using a programmable syringe pump to control the rate of APTEOS infusion into the deposition reservoir. The shape (profile) of the gradient was controlled by the rate of infusion and the gradients were visualized by utilizing a concentration-dependent color formation reaction between amine groups and ninhydrin. The advantages of such gradients in optimizing the retention and separation of various components in different mixtures was illustrated using mixtures of (i) four weak acids and bases and (ii) three widely-used over-the-counter drugs. Thus, the gradient stationary phase was successfully fabricated and applied as a planar chromatographic support. The next step of this research was to prepare continuous amine gradients on silica capillaries as these would be useful in open-tubular capillary electrochromatography for separation of complex mixtures and also to study the retention behavior of various components. This was achieved by carefully infusing micro-volumes of APTEOS solution into the activated silica capillaries. To characterize these gradients, a unique set-up was developed to measure streaming potential and zeta potential along the gradient capillary. Since surface amine groups exist as positively charged groups at acidic and neutral pHs, the measured zeta potential increased from the low amine end to the high amine end of the capillary. In summary, this dissertation work focuses mainly on the development of a simple, rapid and cost-effective method for the preparation of surface chemical gradients. CRI has incredible flexibility and adaptability, which was confirmed by extending it to different substrates such as silica TLC plates and capillary tubes for various applications. The CRI approach is not just helpful in preparing gradients for chromatographic separations; it can be a stable platform to study the reactivity of various precursors which could be a useful tool to develop high-throughput surface modification procedures.

Immunoglobulin E (IgE)-conjugated gold nanoparticles were produced via in situ conjugation of gold nanoparticles with immunoglobulin E by laser ablation of Au in a liquid solution. The colloidal stability and the size distribution of the resulting bio-nanoconjugates were examined with UV-Visible spectroscopy (UV-Vis), dynamic light scattering (DLS), and transmission electron microscopy (TEM). These techniques showed that the Au nanoparticles in aqueous solutions were highly monodispersed spherical particles with a very narrow size distribution. The particles net diameter using TEM, was found to be D5 =3.8±0.9nm and D10 =4.7±1.3nm while the hydrodynamic diameter obtained with DLS was found to be h5 D =171±12nm , h10 D =164±18nm for 5min and 10min laser ablation time respectively. Enzyme-Linked immunosorbent Assay (ELISA) and flow cytometry measurements of the conjugates confirmed that the gold-bound protein remained biologically active, thus paving the way for the application of these nanoparticles in immuno-diagnostics, particularly in tumor-targeted drug delivery.

The Schreier families are a collection of finite subsets of N and have been used to provide refinements of the following Banach space notions: unconditional basic sequences, convergent sequences, spreading model and strictly singular operators to name a few. We use the Schreier families to study subclasses of strictly singular operators on Banach spaces. We also provide a sufficient condition on the strictly singular operators implying every operator falls into one of these subclasses.

Non-covalent interactions involving π-π stacking play an essential role in self-assembly and molecular recognition processes such as protein folding and DNA/RNA-protein selective recognition. The knowledge gained from these studies could provide insight into possible site recognition complexes, inhibiting or mimicking protein-protein or protein-DNA interactions. Based on molecular modeling as well as HOMO and LUMO energies, several chromophores were selected with a variety of ∆ε values (∆ε= |εHOMO,NAcTrp – εLUMO,chromophores|), high and low, to establish a correlating trend with the modeling and experimental data. The corresponding Pt(dien) compounds were synthesized and their ability to stack to N-acetyl tryptophan was evaluated by fluorescence quench experiments. Attaching a strong electron donating/withdrawing group or extending the π system of pyridine or thiazole by means of a benzene ring (quinoline and benzothiazole) was found to enhance the π-π interaction with N-acetyl tryptophan.

In certain experimental situations, the data observed are pseudo-proportional. By this, we observe the numerator, the number of responders, but the denominator, the total number, is random and, possibly, unobserved. In such situations, the data often exhibit "extra" variability due to the randomness of the denominator. Analysis of these data should account for this overdispersion. Several authors have proposed parametric approaches to this problem. Finney [Biometrika (1949) 36, 239-256] proposed the use of a mixture of the binomial and Poisson distributions. Anscombe [Annals of Applied Biology (1949) 36, 203-205] discussed the use of a mixture of the binomial and negative binomial distributions. Margolin et al. [Proceedings of the National Academy of Sciences (1981) 78, 3779-3783] suggested the use of a gamma mixture of Poisson distributions. While it is true that these approaches provide a means of handling overdispersion, the choice of the distributions used often is based on mathematical convenience. To avoid making full distributional assumptions, Kim [Unpublished Ph.D. dissertation (1991), UCLA] applied quasi-likelihood methodology to overdispersed binomial data. In his method, he assumed that the conditional mean and variance of the numerator was that of a binomial distribution, and that the mean of the distribution of the denominator was known, but that its variance was unknown. Using conditional arguments, he arrived at the unconditional mean and variance of the numerator. With the form of the first two moments of the numerator, Kim used quasi-likelihood method of moments estimation to get estimates of the unknown parameters. In this dissertation, Kim's results are generalized to allow the denominator to have an unknown mean and variance, and estimation is achieved using a generalized quasilikelihood method of moments technique. In addition, methodology is developed that allows for overdispersion in both the numerator and denominator. Here, extended quasilikelihood techniques are used for estimation of any unknown parameters. Properties of the estimators were studied via a simulation study which suggests the extended quasilikelihood estimates are not asymptotically normally distributed. Also, goodness-of-link testing is described for use in maximum likelihood, as well as, quasi-likelihood estimation. The methods developed here are illustrated by the analysis of data from a colony formation assay involving serial dilutions.

Bender and Boettcher explored a quantum theory based on a non-Hermitian PT­ symmetric Hamiltonian , where PT is the operator of the space-time reflection and demonstrated that the PT-symmetric Hamiltonian can possess entirely real spectra. In this thesis, we point out that in the framework of PT-symmetric quantum mechanics; the calculation of matrix elements in the Hilbert space is ill-defined. We point out the importance of using CPT inner product in PT-symmetric systems. We manifested our assessment using the CPT inner product prescription for the entangled wave function of the composite system. We show that for a composite system with a local PT-symmetry, it preserves the no-signaling condition and the orthogonality of the states.The reduced density matrix is diagonal and independent of the non-Hermitian parameter . We reaffirm the consistency of PT-symmetric quantum mechanics as a candidate for a fundamental theory .

No description available.

Polyphenols are a group of compounds found naturally in plants and they provide much of the flavor, color, and taste to fruits, vegetables, seeds, and other parts of the plants They also act as antioxidants which provide numerous health benefits by protecting cells against damage caused by free radicals. Their antibacterial, anti-inflammatory and anti-allergenic properties have also contributed to the prevention of degenerative diseases, such as cardiovascular diseases and cancers by slowing the rate of oxidative stress on cells. This study was aimed at the identification and quantitation of a specific polyphenol, quercetin, found in grapes commonly purchased at grocery stores to show their benefits toward human health. Samples of red and black grapes were collected and their polyphenolic compounds were extracted from the pulp using an organic solvent extraction method. High pressure liquid chromatography (hplc) was then used for the determination and quantitation of quercetin in each of samples. Quercetin was identified in both the red and black grape samples at retention times around five minutes. Due to technical problems with the HPLC instrument, only estimates of the amount of quercetin in each of the analyzed samples could be calculated with the highest estimated yield being 8.29 mg/mL of quercetin in black grape extract #4.

The rhodium carboxamide [Rh2(NPhCOCH3)4]L (L=axial ligand), has applications as a catalyst for carbenoid transformations. To explore the nature of the rhodium-carbene bond, studies between Rh2(NPhCOCH3)4 and nitriles were proposed. Trials of the benzonitrile, o-tolunitrile, and m-tolunitrile have been performed and characterized on the 2,2-trans [Rh2(NPhCOCH3)4] complex via NMR spectroscopy, IR spectroscopy, and X-ray crystallography.

The nonlinear Schrödinger equation is a classical field equation that describes weakly nonlinear wave-packets in one-dimensional physical systems. It is in a class of nonlinear partial differential equations that pertain to several physical and biological systems. In this project we apply a pseudo-spectral solution-estimation method to a modified version of the nonlinear Schrödinger equation as a means of searching for solutions that are solitons, where a soliton is a self-reinforcing solitary wave that maintains its shape over time. The pseudo-spectral method estimates solutions by utilizing the Fourier transform to evaluate the spatial derivative within the nonlinear Schrödinger equation. An ode solver is then applied to the resulting ordinary differential equation. We use this method to determine whether cardiac action potential states, which are perturbed solutions to the Fitzhugh-Nagumo nonlinear partial differential equation, create soliton-like solutions. After finding soliton-like solutions, we then use symmetry group properties of the nonlinear Schrödinger equation to explore these solutions. We also use a Lie algebra related to the symmetries to look for more solutions to our modified nonlinear Schrödinger equation.