Physical Sciences and Mathematics Commons^™

Synthesis And Antifungal Evaluation Of Spirostane Saponins, Sunil Upadhyay

University of New Orleans Theses and Dissertations

Methods for the preparation of novel antifungal saponins have been investigated in

order to further explore their medicinal utility and provide the opportunity to synthesize

their derivatives.

Through this work, several partially protected stereoisomers of Cholestane,

Androstane and Spirostane have been prepared which could be used for the synthesis of

various saponin derivatives in order to discover novel saponin based antifungal agent.

Various mono and disaccharide derivatives of these steroids have been synthesized and

evaluated for their antifungal activity against four pathogenic fungal strains. Among the

various derivatives maltose derivatives were found to have the best antifungal activity.

However there …

Crystal Lattice Desolvation Effects On The Magnetic Quantum Tunneling Of Single-Molecule Magnets, G Redler, Christos Lampropoulos, S Datta, C Koo, T C. Stamatatos, N E. Chakov, G Christou, S Hill

Christos Lampropoulos

High-frequency electron paramagnetic resonance (HFEPR) and alternating current (ac) susceptibility measurements are reported for a new high-symmetry Mn12 complex, [Mn12O12(O2CCH3)16(CH3OH)4]⋅CH3OH. The results are compared to those of other high-symmetry spin S=10 Mn12 single-molecule magnets (SMMs), including the original acetate, [Mn12(O2CCH3)16(H2O)4]⋅2CH3CO2H⋅4H2O, and the [Mn12O12(O2CCH2Br)16(H2O)4]⋅4CH2Cl2 and [Mn12O12(O2CCH2But)16(CH3OH)4]⋅CH3OH complexes. These comparisons reveal important insights into the factors that influence the values of the effective barrier to magnetization reversal, Ueff, deduced on the basis of ac susceptibility measurements. In particular, we find that variations in Ueff can be correlated with the degree of disorder in a crystal which can be controlled by desolvating (drying) …

Spin Dynamics In Single-Molecule Magnets Combining Surface Acoustic Waves And High-Frequency Electron Paramagnetic Resonance, F Macià, J Lawrence, S Hill, J M. Hernandez, J Tejada, P V. Santos, Christos Lampropoulos, G Christou

Christos Lampropoulos

We report an experimental technique that integrates high-frequency surface acoustic waves (SAWs) with high-frequency electron paramagnetic resonance (HFEPR) spectroscopy in order to measure spin dynamics on fast time scales in single-molecule magnets. After the system is driven out of equilibrium by triggering magnetic avalanches, or simply by heating with short SAW pulses, the evolution of the spin populations within fixed energy levels is measured using HFEPR spectroscopy.

Alignment Of Magnetic Anisotropy Axes In Crystals Of Mn12 Acetate And Mn12-Tbuac Molecular Nanomagnets: Angle-Dependent Ac Susceptibility Study, E Burzurí, Ch Carbonera, F Luis, D Ruiz-Molina, Christos Lampropoulos, G Christou

Christos Lampropoulos

We report the results of angular-dependent ac susceptibility experiments performed on two derivatives of Mn12 single-molecular magnets: the well-known Mn12 acetate, which contains disordered acetic acid molecules in interstitial sites of the crystal structure and Mn12-tBuAc, for which solvent molecules are very well ordered in the structure. Our results show (a) that the angular variation is very similar in the two compounds investigated and compatible with a maximum misalignment of the anisotropy axes of less than 3° and (b) that the tunneling rate is faster for the better ordered Mn12-tBuAc compound. These experiments question interstitial disorder as the dominant origin …

Realization Of Random-Field Ising Ferromagnetism In A Molecular Magnet, Bo Wen, P Subedi, Lin Bo, Y Yeshurun, M P. Sarachik, A D. Kent, A J. Millis, Christos Lampropoulos, G Christou

Christos Lampropoulos

The longitudinal magnetic susceptibility of single crystals of the molecular magnet Mn12-acetate obeys a Curie-Weiss law, indicating a transition to a ferromagnetic phase at ∼0.9 K. With increasing magnetic field applied transverse to the easy axis, a marked change is observed in the temperature dependence of the susceptibility, and the suppression of ferromagnetism is considerably more rapid than predicted by mean-field theory for an ordered single crystal. Our results can instead be fit by a Hamiltonian for a random-field Ising ferromagnet in a transverse magnetic field, where the randomness derives from the intrinsic distribution of locally tilted magnetic easy axes …

Effects Of Quantum Mechanics On The Deflagration Threshold In The Molecular Magnet Mn12 Acetate, F Macià, J M. Hernandez, J Tejada, S Datta, S Hill, Christos Lampropoulos, G Christou

Christos Lampropoulos

We report experimental studies of the stability of a Mn12-Ac crystal against magnetic avalanches as a function of the magnitude and direction of the magnetic field, as well as a function of temperature. Strong evidence for quantum effects associated with this phenomenon is seen in the (Hz,Hx) metastability diagram. The data provide further support to the theory of magnetic deflagration.

Experimental Determination Of The Weiss Temperature Of Mn12-Ac And Mn12-Ac-Meoh, Christos Lampropoulos, Shiqi Li, Lin Bo, Bo Wen, M P. Sarachik, P Subedi, A D. Kent, Y Yeshurun, A J. Millis, S Mukherjee, G Christou

Christos Lampropoulos

We report measurements of the susceptibility in the temperature range from 3.5 to 6.0 K of a series of Mn12-ac and Mn12-ac-MeOH samples in the shape of rectangular prisms of length lc and square cross section of side la. The susceptibility obeys a Curie-Weiss law, χ=C/(T−θ), where θ varies systematically with sample aspect ratio. Using published demagnetization factors, we obtain θ for an infinitely long sample corresponding to intrinsic ordering temperatures Tc≈0.85 K and ≈0.74 K for Mn12-ac and Mn12-ac-MeOH, respectively. The difference in Tc for two materials that have nearly identical unit cell volumes and lattice constant ratios suggests …

Evaluation Of Pgaa Data For Provenance Of Lithic Artifacts, Otis N. Crandell

Studia UBB Geologia

The objectives of the study were to determine whether Prompt Gamma Activation Analyses (PGAA) could be successfully used to trace the source(s) of various Neolithic artifacts made of microcrystaline quartz. Two macroscopically identical sources of jasper from central and western Romania were analyzed by PGAA along with five Neolithic artifacts from the Limba site (Alba County). Due to the limited number of trace elements, which can be measured by PGAA, this method when used alone might produce inconclusive results for discriminating between jaspers from different sources. The interpretation of the data may be used for general assessments of provenance involving …

Quantitative Field Testing Rotylenchulus Reniformis Dna From Metagenomic Samples Isolated Directly From Soil., Kurt Showmaker, Gary W. Lawrence, Shien Lu, Clarissa Balbalian, Vincent P. Klink

College of Agriculture & Life Sciences Publications and Scholarship

A quantitative PCR procedure targeting the ?-tubulin gene determined the number of Rotylenchulus reniformis Linford & Oliveira 1940 in metagenomic DNA samples isolated from soil. Of note, this outcome was in the presence of other soil-dwelling plant parasitic nematodes including its sister genus Helicotylenchus Steiner, 1945. The methodology provides a framework for molecular diagnostics of nematodes from metagenomic DNA isolated directly from soil.

3-D Transient Hydraulic Tomography In Unconfined Aquifers With Fast Drainage Response, Michael Cardiff, Warren Barrash

CGISS Publications and Presentations

We investigate, through numerical experiments, the viability of three-dimensional transient hydraulic tomography (3DTHT) for identifying the spatial distribution of groundwater flow parameters (primarily, hydraulic conductivity K) in permeable, unconfined aquifers. To invert the large amount of transient data collected from 3DTHT surveys, we utilize an iterative geostatistical inversion strategy in which outer iterations progressively increase the number of data points fitted and inner iterations solve the quasi-linear geostatistical formulas of Kitanidis. In order to base our numerical experiments around realistic scenarios, we utilize pumping rates, geometries, and test lengths similar to those attainable during 3DTHT field campaigns performed at …

Roman: Routing And Opportunistic Management Of Airborne Networks, Hemanth Meka, Lekshmi Manian Chidambaram, Sanjay K. Madria, Mark Linderman, Mohan Kumar, Sharma Chakravarthy

Computer Science Faculty Research & Creative Works

Most of the routing and replication algorithms for Mobile Peer to Peer (M-P2P) networks assume the network to be large and therefore, the architecture and algorithms are designed to be scalable. These algorithms however may not perform well with limited number of nodes in a network such as of UAVs. Thus, it is better to design algorithms to increase the efficiency of a small network if scalability is no longer an issue. for such small networks, we design and simulate an effective two layered graph-based routing algorithm using store/forward concept. We also take into account UAVs orientation and configuration of …

Reactions With Platinum (Ll) Complexes And Selenium-Containing Amino Acids, Stephanie Robey

Mahurin Honors College Capstone Experience/Thesis Projects

We have reacted [Pt(Me₄en)(D₂O)₂]²⁺ [Me₄En=N,N,N’N’-tetramethylethylenediamine] with Selenomethionine (SeMet), Methionine (Met), and Methylselenocysteine (MeSeCys). When MeSeCys was reacted with [Pt(Me₄en)(D₂O)₂]²⁺, we observed both stereoisomers of Se,N chelates, as well as [Pt(Me₄en)(MeSeCys)Cl]⁺ from ­¹­H NMR Spectroscopy; the latter formed due to the presence of Cl^- in the solution. Both isomers of the chelate seemed to form proportionally to one another, not favoring a specific stereoisomer. Eventually the [Pt(Me₄en)(MeSeCys)Cl]⁺ products became Se,N chelates. We incubated SeMet with …

Influence Of Weak Interactions On Supramolecular Binding: Characterization Of Cucurbituril Complexes With Alkylmonoammonium Ions Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, Ruijan Shi

Theses and Dissertations

This thesis focuses on using mass spectrometry-based techniques for characterizing the structure and behavior of cucurbituril complexes in the gas phase. Both solvent and counter ion effects can be completely eliminated in the gas phase and the intrinsic interactions in the system are directly shown in the experimental results. Chapter 1 introduces the structures, properties and host-guest chemistry of cucurbituril, and FTICR mass spectrometry including instrumentation, performance and working principles. Two mass spectrometry-based methods for supramolecular characterization, sustained off-resonance irradiation collision induced dissociation (SORI CID) and ion molecule equilibrium measurements, are also discussed in this chapter. Chapter 2 characterizes the …

Nonparametric Copula Density Estimation In Sensor Networks, Leming Qu, Hao Chen, Yicheng Tu

Mathematics Faculty Publications and Presentations

Statistical and machine learning is a fundamental task in sensor networks. Real world data almost always exhibit dependence among different features. Copulas are full measures of statistical dependence among random variables. Estimating the underlying copula density function from distributed data is an important aspect of statistical learning in sensor networks. With limited communication capacities or privacy concerns, centralization of the data is often impossible. By only collecting the ranks of the data observed by different sensors, we estimate and evaluate the copula density on an equally spaced grid after binning the standardized ranks at the fusion center. Without assuming any …

Study Of The Vaporization Enthalpies By Correlation-Gas Chromatography, Dmitry Lipkind

Dissertations

The focus of this thesis is on the measurement and collection of thermodynamic and physical property data, including vaporization, fusion, and sublimation enthalpies and vapor pressures of large n-alkanes, nitrogen heterocycles and related compounds by a technique developed in our laboratory referred to as correlation-gas chromatography (C-GC). These thermodynamic data are of importance to several disciplines that include chemical engineering, as well as the pharmaceutical and the petrochemical industries. Vapor pressures of large hydrocarbons are fundamental data required in the petroleum industry to develop thermodynamic models for dealing with crude oil. Environmental chemists and engineers use vapor pressures and vaporization …

The Vulnerability Assessment And Penetration Testing Of Two Networks, Steven L. Simpson

Regis University Student Publications (comprehensive collection)

Vulnerability assessments and penetration testing are two approaches available for use by internet security practitioners to determine the security posture of information networks. By assessing network vulnerabilities and attempting to exploit found vulnerabilities through penetration testing security professionals are able to evaluate the effectiveness of their network defenses by identifying defense weaknesses, affirming the defense mechanisms in place, or some combination of the two. This project is a discussion of the methods and tools used during the vulnerability assessment and penetration testing, and the respective test results of two varied and unique networks. The assessment and testing of the first …

Nonparametric Copula Density Estimation In Sensor Networks, Leming Qu, Hao Chen, Yicheng Tu

Leming Qu

Statistical and machine learning is a fundamental task in sensor networks. Real world data almost always exhibit dependence among different features. Copulas are full measures of statistical dependence among random variables. Estimating the underlying copula density function from distributed data is an important aspect of statistical learning in sensor networks. With limited communication capacities or privacy concerns, centralization of the data is often impossible. By only collecting the ranks of the data observed by different sensors, we estimate and evaluate the copula density on an equally spaced grid after binning the standardized ranks at the fusion center. Without assuming any …

Technology Enhanced Learning: Students' Views, Eileen O'Donnell, Mary Sharp

Eileen O'Donnell

User feedback is very important in all areas of computer science especially in the development of computer applications. Hence, student feedback on the use of technology enhanced learning in higher education in Ireland is relevant to the quality of the learning resources to be created by learning designers and academics in the future. The book “Student Reactions to Learning with Technologies: Perceptions and Outcomes” (Moyle & Wijngaards, 2012) was published by IGI Global in October 2011. This book includes contributions from various authors who are interested in students’ feedback regarding how technology has impacted on their educational experience. This book …

Identification And Efficient Estimation Of The Natural Direct Effect Among The Untreated, Samuel D. Lendle, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

The natural direct effect (NDE), or the effect of an exposure on an outcome if an intermediate variable was set to the level it would have been in the absence of the exposure, is often of interest to investigators. In general, the statistical parameter associated with the NDE is difficult to estimate in the non-parametric model, particularly when the intermediate variable is continuous or high dimensional. In this paper we introduce a new causal parameter called the natural direct effect among the untreated, discus identifiability assumptions, and show that this new parameter is equivalent to the NDE in a randomized …

Absolute Quantification Of Gene Expression In Individual Bacterial Cells Using Two-Photon Fluctuation Microscopy, Matthew L. Ferguson, Dominique Le Coq, Matthieu Jules, Stéphane Aymerich, Nathalie Declerck, Catherine A. Royer

Matthew L. Ferguson

Quantification of promoter activity or protein expression in gene regulatory networks is generally achieved via measurement of fluorescent protein (FP) intensity, which is related to the true FP concentration by an unknown scaling factor, thereby limiting analysis and interpretation. Here, using approaches originally developed for eukaryotic cells, we show that two-photon (2p) fluorescence fluctuation microscopy, specifically scanning number and brightness (sN&B) analysis, can be applied to determine the absolute concentrations of diffusing FPs in live bacterial cells. First, we demonstrate the validity of the approach, despite the small size of the bacteria, using the central pixels and spatial averaging. We …

Hydrological Parameter Estimations From A Conservative Tracer Test With Variable-Density Effects At The Boise Hydrogeophysical Research Site, B. Dafflon, Warren Barrash, Michael Cardiff, T. C. Johnson

CGISS Publications and Presentations

Reliable predictions of groundwater flow and solute transport require an estimation of the detailed distribution of the parameters (e.g., hydraulic conductivity, effective porosity) controlling these processes. However, such parameters are difficult to estimate because of the inaccessibility and complexity of the subsurface. In this regard, developments in parameter estimation techniques and investigations of field experiments are still challenging and necessary to improve our understanding and the prediction of hydrological processes. Here we analyze a conservative tracer test conducted at the Boise Hydrogeophysical Research Site in 2001 in a heterogeneous unconfined fluvial aquifer. Some relevant characteristics of this test include: variable-density …

Empirical Study Of An Intelligent Argumentation System In Mcdm, Xiaoqing Liu, Rubal Wanchoo, Ravi Santosh Arvapally

Computer Science Faculty Research & Creative Works

Intelligent argumentation based collaborative decision-making system assists stakeholders in a decision-making group to assess various alternatives under different criterion based on the argumentation. a performance score of each alternative under every criterion in Multi-Criteria Decision Making (MCDM) is represented in a decision matrix and it denotes satisfaction of the criteria by that alternative. the process of determining the performance scores of alternatives in a decision matrix for criterion could be controversial sometimes because of the subjective nature of criterion. We developed a framework for acquiring performance scores in a decision matrix for multi-criteria decision making using an intelligent argumentation and …

Lagrange's Theory Of Analytical Functions And His Ideal Of Purity Of Method, Giovanni Ferraro, Marco Panza

MPP Published Research

We reconstruct essential features of Lagrange’s theory of analytical functions by exhibiting its structure and basic assumptions, as well as its main shortcomings. We explain Lagrange’s notions of function and algebraic quantity, and we concentrate on power-series expansions, on the algorithm for derivative functions, and the remainder theorem—especially on the role this theorem has in solving geometric and mechanical problems. We thus aim to provide a better understanding of Enlightenment mathematics and to show that the foundations of mathematics did not, for Lagrange, concern the solidity of its ultimate bases, but rather purity of method—the generality and internal organization of …

Lesson Not Learned: Deepwater Horizon Research And Media Coverage Exposes Gaps In Knowledge And Risky Protocol Within The Oil Industry, Lauren Haller

Honors Theses

An insatiable thirst for oil has led poorly coordinated, risk-prone megasystems deeper into the ocean in search of new oil reserves. Profit-driven agendas at the corporate level have a top-down effect within these megasystems. Cost-cutting and risk-downplaying leaves the field employees unprepared to handle emergencies. A series of costly mistakes led to the 2010 BP Deepwater Horizon oil spill, which caused extensive damage to an already fragile ecosystem in the Gulf of Mexico. The wealth and political influence of the oil industry overpowers lax regulatory agencies and legislation-even though media and research has exposed frustrating parallels between the Deepwater Horizon …

Photocatalytic Activity Of Zinc Oxide Thin Films Prepared By Dc Sputter Deposition And Thermal Oxidation, Robert Louder

Honors Theses

Zinc oxide (ZnO) is a wide-bandgap semiconductor with a broad range of applications, such as photocatalysis. The photocatalytic properties of ZnO result from the highly oxidizing holes and reducing electrons that are induced on the ZnO surface by ultraviolet (UV) light. The efficiency of electron-hole pair formation is therefore critical for photocatalysis, and thus the optical quality of the films in the UV region is of critical importance. ZnO thin films have been fabricated using DC sputter deposition of Zn-metal films followed by thermal oxidation at different temperatures (300, 600, and 900°C). Characterization of the optical properties of the resulting …

Multimessenger Astronomy: Modeling Gravitational And Electromagnetic Radiation From A Stellar Binary System, Kevin Kern

Honors Theses

Our Solar System is one of roughly 100 billion other stars that make up the Milky Way Galaxy. Two-thirds of all stars are paired off, forming a gravitational bond between one another. Such systems are known as stellar binaries. Although these binaries are prevalent there is much yet to be learned about their formation, evolution, and interactions. The approach taken in this thesis is to produce simulated data representing the expected measurements that an observational astronomer would collect. Specifically, we have simulated the data from an eclipsing binary light curve, spectroscopic velocity curve, and the gravitational wave times series form …

2011 Fall Engr333 Project Final Report, Fall 2011 Engr333

ENGR 333

Analysis of the Bunker Interpretive Center (BIC) began during the spring of 2011 with the Engineering 382 Instrumentation Lab. To determine the energy use at the BIC, sensing equipment was placed on 44 different energy consuming devices, ranging from pumps to lights to heating and ventilation (HVAC) equipment. These data were collected over the spring and summer and then analyzed by the Engineering 333 Thermal Systems Design class during the fall of 2011. The class was tasked with determining whether or not the BIC was eligible for Energy Star certification. While the building was built to be LEED Gold certified, …

Molecular Dynamics Studies Of Interactions Of Phospholipid Membranes With Dehydroergosterol And Penetrating Peptides, Amir Mohsen Pourmousa Abkenar

Electronic Thesis and Dissertation Repository

We have performed molecular modeling of membrane and peptide systems by employing the classical molecular dynamics method and force field parameterizations. In this thesis, our main interest is the interaction of sterols as well as peptides with membranes. The thesis consists of three related projects. The first project focuses on cholesterol (CHOL) and dehydroergosterol (DHE) interacting with palmitoyl-oleoyl phosphatidylcholine (POPC) lipid bilayers. We study the effects of both sterols on the bilayer and compare them with each other. We first study the condensing and ordering effect of these sterols. Then, we study their orientations within the bilayer and relate them …

Fragile Binary Candidates In The Sdss Dr8 Spectroscopic Archive, J. K. Zhao, Terry D. Oswalt, G. Zhao

Publications

We present a catalog of 80 very wide fragile binary candidates (projected separations >10,000 AU) from the Sloan Digital Sky Survey Data Release Eight spectral archive. The pairs were selected based on proper motion, radial velocity, metallicity, and photometric parallax criteria. The angular separations of these pairs range from 3'' to 250''. The peak in the metallicity distribution of these pairs is about −0.5 dex of solar metallicity. Space motions and reduced proper motion diagrams indicate that all these pairs are members of the disk. The chromospheric activity index S_HK of each component in 38 binary candidates having spectra …

A General Model For Continuous Noninvasive Pulmonary Artery Pressure Estimation, Robert Anthony Smith

Theses and Dissertations

Elevated pulmonary artery pressure (PAP) is a significant healthcare risk. Continuous monitoring for patients with elevated PAP is crucial for effective treatment, yet the most accurate method is invasive and expensive, and cannot be performed repeatedly. Noninvasive methods exist but are inaccurate, expensive, and cannot be used for continuous monitoring. We present a machine learning model based on heart sounds that estimates pulmonary artery pressure with enough accuracy to exclude an invasive diagnostic operation, allowing for consistent monitoring of heart condition in suspect patients without the cost and risk of invasive monitoring. We conduct a greedy search through 38 possible …