Physical Sciences and Mathematics Commons^™

Investigating The Allosteric Behavior Of Malate Dehydrogenase From Escherichia Coli, Eman M. Ghanem

Masters Theses

Regulatory mechanisms of malate dehydrogenase from E.coli (eMDH) involving NADH as an allosteric effector were investigated. The reaction was studied in both directions: malate oxidation and oxaloacetate reduction. When malate was the variable substrate, a plot of rate against substrate concentration was sigmoidal in the presence of 0.065 mM NADH, which indicates the presence of an allosteric site for NADH on the enzyme. Binding of NADH at the allosteric site causes conformational changes in the active site and, thereby, changes the catalytic activity of the enzyme. An increase in K_m value, from 1.3 to 3.9 mM malate was observed, …

Optimization Of The Reaction Of Hexamethyldisilazane On A Fumed Silica Surface, Frederick R. Jones

Masters Theses

Hexamethyldisilazane (HMDS) is commonly used to transfer trimethylsilyl (TMS) groups to silica surfaces. While studies have been done examining individual factors that influence the reaction, no investigations have reported how these factors affect each other. The factors examined in this study include temperature, presence of catalyst (butylamine), pretreatment, time, concentration, solvent, and presence of water in the solvent. The purpose of this study is to examine potential factors and two-way interactions to determine which significantly affect the yield and produce an optimum set of conditions.

The HMDS reactions occurred in an organic solvent slurry under nitrogen. Using statistical experimental design, …

The Cytotoxicity And Mode Of Action Of 2,3,4-Trisubstituted Pyrroles And Related Derivatives In Human Tmolt4 Leukemia Cells, John T. Gupton, B. S. Burham, B. D. Byrd, K. E. Krumpe, C. Stokes, J. Shuford, S. Winkle, T. Webb, A. E. Warren, C. R. Barnes, J. Henry, I. H. Hall

Chemistry Faculty Publications

4-Carbechoxy-l-methyl-2-phenacyl-3-phenylpyrrole (9), 4-carbethoxy-2-(4-methoxybcnzoyl)-3-(4-methoxyphcnyl)pyrrole (10) and 2-(4-methoxybenzoyl)-3,4-bis-(4-methoxyphenyl)pyrrole (11) proved to be potent cytotoxic agents against the growth of murine and human leukemias and lymphomas. Selective toxicity was demonstrated against the growth of solid tumors, e.g. human adenocarcinoma of the colon SW480 and ileum HCT-8, glioma U-87-MG, and rat UMR-106 osteosarcoma. A mode of action study in Tmolt₄ leukemia cells demonstrated that the agents inhibited de novo purine synthesis at the regulatory sites PRPP-amido transferase, IMP dehydrogenase as well as dihydrofolate reductase resulting in significant inhibition of DNA synthesis in 60 min. Other biochemical sites …

Assessment Of The Availability And Exploitation Of Hydric Resources In The Choquenaira Community, Luis Lizardo Iturry Urquizo

Theses and Dissertations

The precipitation data of the El Alto, Tambillo and Comanche stations are homogenous and consistent. The meteorological data from Irpa Chico, Collana and Viacha are consistent, but heterogeneous. The monthly precipitation in Viacha in December, January, March and April are better examples of a normal distribution in comparison to the months of October, November and February. The average annual precipitation in Viacha, in a thirty-four year time period, is 559 mm. Some 76% of this precipitation occurs in November to March. The minimum precipitation in Viacha, with an 80% probability of absence for the vegetative period, from October to April …

How Do Judges Think About Risk?, W. Kip Viscusi

Vanderbilt Law School Faculty Publications

A sample of almost 100 judges exhibited well-known patterns of biases in risk beliefs and reasonable implicit values of life. These biases and personal preferences largely do not affect attitudes toward judicial risk decisions, though there are some exceptions, such as ambiguity aversion, misinterpretation of negligence rules, and retrospective risk assessments in accident cases, which is a form of hindsight bias. Although judges avoided many pitfalls exhibited by jurors and the population at large, they nevertheless exhibited systematic errors, particularly for small probability-large loss events. These findings highlighted the importance of judicial review and the input of expert risk analysts …

Vitamin Effect On The Aerobic Biodegradation Of Phenanthrene, Antracene, Fluoranthene, And Pyrene In A Contaminated Soil From An Industrial Site, Ilkay Cam

Theses

Bioremediation of organic wastes is often a cost-effective technology for the in situ treatment of contaminated soils. In this study, the possibility of increasing the rate and extent of biodegradation for phenathrene, anthracene, fluoranthene, and pyrene in an industrial PAH contaminated soil via vitamin mixture supplementation was explored.

Soil contained with PAHs was obtainecl from the Bayway refinery site formerly owned by Exxon (Linden, NJ). Experiments were conducted in which the contaminated soil was amended with a mixtures of four vitamins (niacin, biotin, folic acid, and panthothenic acid). Peat moss, a common soil amendment, was also added in some experiments. …

Late-Time Optical And Ultraviolet Spectra Of Sn 1979c And Sn 1980k, Robert A. Fesen, Christopher L. Gerardy, Alexei V. Filippenko, Thomas Matheson, Roger A. Chevalier, Robert P. Kirshner, Brian P. Schmidt, Peter Challis, Claes Fransson, Bruno Leibundgut, Schuyler D. Van Dyk

Dartmouth Scholarship

A low-dispersion Keck I spectrum of SN 1980K taken in 1995 August (t = 14.8 yr after explosion) and a spectrum taken in 1997 November (t = 17.0 yr) at the MDM Observatory show broad 5500 km s^-1 emission lines of Hα, [O I] 6300, 6364 Å, and [O II] 7319, 7330 Å. Weaker but similarly broad lines detected include [Fe II] 7155 Å, [S II] 4068, 4072 Å, and a blend of [Fe II] lines at 5050–5400 Å. The presence of strong [S II] 4068, 4072 Å emission but a lack of [S II] 6716, 6731 …

Uneconomic Growth: In Theory, In Fact, In History, And In Relation To Globalization, Herman E. Daly

Clemens Lecture Series

No abstract provided.

Critical Adsorption Near Edges, Andreas Hanke, M. Krech, F. Schlesener, S. Dietrich

Physics & Astronomy Faculty Publications

Symmetry breaking surface fields give rise to nontrivial and long-ranged order parameter profiles for critical systems such as fluids, alloys, or magnets confined to wedges. We discuss the properties of the corresponding universal scaling functions of the order parameter profile and the two-point correlation function, and determine the critical exponents η∥ and η⊥ for the so-called normal transition.

Apex: Cross-Platform Analysis Program For Exafs, Nicholas Dimakis, Grant Bunker

Physics & Astronomy Faculty Publications

We have developed version 1.0 of a freely available (including source code) suite of basic X-Ray Absorption Fine Structure (XAFS) data analysis programs for data reduction and single scattering analysis. This package is based on the University of Washington (UW/NRL) Fortran 77 programs that are available on the International XAFS Society (IXS) database, complemented by a graphical TCL/TK scripting language based user interface which runs virtually unchanged between platforms, using the native look and feel of the corresponding platform. The package has been tested on MacOS 8.1, Linux, IRIX, Windows95 and NT. Particular emphasis is placed on simplicity, reliability, and …

Polymer Depletion Effects Near Mesoscopic Particles, Andreas Hanke, E. Eisenriegler, S. Dietrich

Physics & Astronomy Faculty Publications

The behavior of mesoscopic particles dissolved in a dilute solution of long, flexible, and nonadsorbing polymer chains is studied by field-theoretic methods. For spherical and cylindrical particles the solvation free energy for immersing a single particle in the solution is calculated explicitly. Important features are qualitatively different for self-avoiding polymer chains as compared with ideal chains. The results corroborate the validity of the Helfrich-type curvature expansion for general particle shapes and allow for quantitative experimental tests. For the effective interactions between a small sphere and a wall, between a thin rod and a wall, and between two small spheres, quantitative …

Regional Ecology Of The St. Elias Mountain Parks: A Synthesis With Management Implications (British Columbia, Yukon, Alaska), Ryan Kenneth Danby

Theses and Dissertations (Comprehensive)

The St. Elias region of North America occupies portions of British Columbia, Alaska, and the Yukon Territory and comprises a network of public lands and protected areas managed by a variety of agencies. This thesis characterizes and analyzes the broad- scale, or regional, ecology of these lands and provides an assessment of the implications this has for ecosystem-based management—particularly as it relates to intergovernmental cooperation. A multi-stage, map-based, multidisciplinary process is used to synthesize information on the region’s physical, biological, and institutional environments. The fields of conservation biology and landscape ecology provide theoretical foundations for analysis. The ecological synthesis and …

Efficient Dynamic Unstructured Methods And Applications For Transonic Flows And Hypersonic Stage Separation, Xiaobing Luo

Mechanical & Aerospace Engineering Theses & Dissertations

Relative-moving boundary problems have a wide variety of applications. They appear in staging during a launch process, store separation from a military aircraft, rotor-stator interaction in turbomachinery, and dynamic aeroelasticity.

The dynamic unstructured technology (DUT) is potentially a strong approach to simulate unsteady flows around relative-moving bodies, by solving time-dependent governing equations. The dual-time stepping scheme is implemented to improve its efficiency while not compromising the accuracy of solutions. The validation of the implicit scheme is performed on a pitching NACA0012 airfoil and a rectangular wing with low reduced frequencies in transonic flows. All the matured accelerating techniques, including the …

Decision Analytic Approach To Severe Head Injury Management., Harmanec D., Tze-Yun Leong, Sundaresh S., Poh K., Yeo T., Ng I., Lew T.

Research Collection School Of Computing and Information Systems

Severe head injury management in the intensive care unit is extremely challenging due to the complex domain, the uncertain intervention efficacies, and the time-critical setting. We adopt a decision analytic approach to automate the management process. We document our experience in building a simplified influence diagram that involves about 3000 numerical parameters. We identify the inherent problems in structuring a model with unclear domain relationships, numerous interacting variables, and real-time multiple inputs. We analyze the effectiveness and limitations of the decision analytic approach and present a set of desiderata for effective knowledge acquisition in this setting. We also propose a …

Determination Of The Lep Centre-Of-Mass Energy From Zγ Events, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A study of events with photons and missing energy has been performed with the data sample obtained with the ALEPH detector at centre-of-mass energies from 161 to 184 GeV, corresponding to a total integrated luminosity of about 80 pb−1. The measured distributions are in agreement with Standard Model predictions, leading to constraints on WWγ gauge coupling parameters ∆κγ and λγ. The results from the fit to the cross sections and to the energy and angular distributions of the photons are: ∆κγ = 0.05+1.15 −1.10(stat)±0.25(syst) λγ = −0.05+1.55 −1.45(stat)±0.30(syst).

Measurement Of W-Pair Production In E+E- Collisions At 183 Gev, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

The production of W+W− pairs is analysed in a data sample collected by ALEPH at a mean centre-of-mass energy of 182.7 GeV, corresponding to an integrated luminosity of 57 pb−1 . Cross sections are given for different topologies of W decays into leptons or hadrons. Under Standard Model assumptions for the W-pair production and decay, the W-pair cross section is measured to be 15.57 ± 0.62(stat.) ± 0.29(syst.) pb. Using also the W-pair data samples collected by ALEPH at lower centre-of-mass energies, the decay branching ratio of the W boson into hadrons is measured to be B(W → hadrons) = …

Monitoring The Stability Of The Aleph Vertex Detector, G. Sguazzoni, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

The ALEPH Silicon Vertex Detector features an optical fibre laser system to monitor its mechanical stability. The operating principle and the general performance of the laser system are described. The experience obtained during 1997 and 1998 operations confirms the important role that such a system can have with respect to the detector alignment requirements. In particular, the laser system has been used to monitor short-term temperature-related effects and long-term movements. These results and a description of the laser-based alignment correction applied to the 1998 data are presented.

Search For Invisible Higgs Boson Decays In E+E- Collisions At Centre-Of-Mass Energies Up To 184 Gev, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

In a data sample of 78.3 pb−1 collected in 1996 and 1997 by the ALEPH detector at centre-of-mass energies from 161 to 184 GeV, invisible decays of a Higgs boson have been searched for in the reaction e+e− → hZ, where the Z can decay into e+e−, µ+µ− or q¯q. No evidence for a signal is found and limits on the production cross section are derived as a function of the Higgs boson mass. These results are combined with those obtained in an update of the analyses of the ALEPH data taken at LEP 1. For a production cross section …

Measurement Of The Hadronic Photon Structure Function At Lep 1 For 〈Q2〉 Values Between 9.9 And 284 Gev2, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

Inclusive γ∗γ interactions to hadronic final states where one scattered electron or positron is detected in the electromagnetic calorimeters have been studied in the LEP 1 data taken by ALEPH from 1991 to 1995. The event sample has been used to measure the hadronic structure function of the photon F2γ in three bins with 〈Q2〉 of 9.9, 20.7 and 284 GeV2.

Search For The Standard Model Higgs Boson At The Lep2 Collider Near √S = 183 Gev, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

During 1997 the ALEPH experiment at LEP gathered 57pb−1 of data at centre-of-mass energies near 183 GeV. These data are used to look for possible signals from the production of the Standard Model Higgs boson in the reaction e+e−→HZ. No evidence of a signal is found in the data; seven events are selected, in agreement with the expectation of 7.2 events from background processes. This observation results in an improved lower limit on the mass of the Higgs boson: mH>87.9GeV/c2 at 95% confidence level.

Determination Of |Vub| From The Measurement Of The Inclusive Charmless Semileptonic Branching Ratio Of B Hadrons, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

From a study of the kinematic properties of the final state produced in the semileptonic decays b→Xℓνℓb→Xℓνℓ, the inclusive charmless semileptonic branching ratio of b hadrons is measured. With a sample of 3.6 million hadronic Z decays recorded between 1992 and 1995 with the ALEPH detector at LEP, the value Br(b→Xuℓνℓ)Br(b→Xuℓνℓ) is determined to be (1.73±0.55stat±0.55syst)×10−3(1.73±0.55stat±0.55syst)×10−3, where XuXu represents any charmless hadronic state and b is a mixture of b hadrons weighted by their production rates. This measurement yields the result|Vub|2=(18.68±5.94stat±5.94syst±1.45HQE)×10−6,|Vub|2=(18.68±5.94stat±5.94syst±1.45HQE)×10−6,where the last error comes from the conversion of the branching ratio to the CKM matrix element squared.

One-Prong Τ Decays With Kaons, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

One-prong ττ decays into final states involving kaons are studied with about 161 000 τ+τ−τ+τ− events collected by the ALEPH detector from 1991 to 1995. Charged kaons are identified by dE/dx measurement, while K0LKL0's are detected through their interaction in calorimeters. Branching ratios are measured for the inclusive mode, B(τ−→K−Xντ)=(1.52±0.04±0.04)%B(τ−→K−Xντ)=(1.52±0.04±0.04)%, where X can be any system of neutral particles, and for the exclusive modesB(τ−→K−ντ)=(6.96±0.25±0.14)×10−3,B(τ−→K−π0ντ)=(4.44±0.26±0.24)×10−3,B(τ−→K−π0π0ντ)=(0.56±0.20±0.15)×10−3,B(τ−→K−π0π0π0ντ)=(0.37±0.21±0.11)×10−3,B(τ−→K−K0ντ)=(1.62±0.21±0.11)×10−3,B(τ−→K−K0π0ντ)=(1.43±0.25±0.15)×10−3,B(τ−→K0¯¯¯¯¯¯¯π−ντ)=(9.28±0.45±0.34)×10−3,B(τ−→K0¯¯¯¯¯¯¯π−π0ντ)=(3.47±0.53±0.37)×10−3,B(τ−→K−ντ)=(6.96±0.25±0.14)×10−3,B(τ−→K−π0ντ)=(4.44±0.26±0.24)×10−3,B(τ−→K−π0π0ντ)=(0.56±0.20±0.15)×10−3,B(τ−→K−π0π0π0ντ)=(0.37±0.21±0.11)×10−3,B(τ−→K−K0ντ)=(1.62±0.21±0.11)×10−3,B(τ−→K−K0π0ντ)=(1.43±0.25±0.15)×10−3,B(τ−→K0¯π−ντ)=(9.28±0.45±0.34)×10−3,B(τ−→K0¯π−π0ντ)=(3.47±0.53±0.37)×10−3,where the first error is statistical and the second is systematical. Upper limits for B(τ−→K0¯¯¯¯¯¯¯π−π0π0ντ)B(τ−→K0¯π−π0π0ντ) and B(τ−→K−K0π0π0ντ)B(τ−→K−K0π0π0ντ) are also obtained. Mass spectra in the final states are investigated in order to study the relevant dynamics.

Search For Bs0 Oscillations Using Inclusive Lepton Events, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

A search for B0sBs0 oscillations is performed using a sample of semileptonic b-hadron decays collected by the ALEPH experiment during 1991–95. Compared to previous inclusive lepton analyses, the proper time resolution and b-flavour mistag rate are significantly improved. Additional sensitivity to B0sBs0 mixing is obtained by identifying subsamples of events having a B0sBs0 purity which is higher than the average for the whole data sample. Unbinned maximum likelihood amplitude fits are performed to derive a lower limit of Δms>9.5ps−1Δms>9.5ps−1 at the 95% confidence limit (95% CL). Combining with the ALEPH D−sDs−-based analyses yields Δms>9.6ps−1Δms>9.6ps−1 at 95% …

Search For Supersymmetry With A Dominant R-Parity Violating Lqd̄ Coupling In E+E- Collisions At Centre-Of-Mass Energies Of 130 Gev To 172 Gev, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

A search for pair-production of supersymmetric particles under the assumption that R-parity is violated via a dominant LQD¯LQD¯ coupling has been performed using the data collected by ALEPH at centre-of-mass energies of 130–172 GeV. The observed candidate events in the data are in agreement with the Standard Model expectation. This result is translated into lower limits on the masses of charginos, neutralinos, sleptons, sneutrinos and squarks. For instance, for m0=500m0=500 GeV/c2/c2 and tanβ=2–√tan⁡β=2 charginos with masses smaller than 81 GeV/c2/c2 and neutralinos with masses smaller than 29 GeV/c2/c2 are excluded at the 95% confidence level for any generation structure of …

Study Of T Decays Involving Kaons, Spectral Functions And Determination Of The Strange Quark Mass, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

All ALEPH measurements of branching ratios of ττ decays involving kaons are summarized including a combination of results obtained with K0SKS0 and K0LKL0 detection. The decay dynamics are studied, leading to the determination of contributions from vector K∗(892)K∗(892) and K∗(1410)K∗(1410), and axial-vector K1(1270)K1(1270) and K1(1400)K1(1400) resonances. Agreement with isospin symmetry is observed among the different final states. Under the hypothesis of the conserved vector current, the spectral function for the KK¯¯¯¯¯πKK¯π mode is compared with the corresponding cross section for low energy e+e−e+e− annihilation, yielding an axial-vector fraction of (94+6−8)%(94−8+6)% for this mode. The branching ratio for ττ decay into …

Developing Database Applications By Using Software Components, Nusret Conk

College of Graduate Studies: Theses & Dissertations (1964–2006)

Today, the software application development process is more assembly work than a "build from scratch" approach. By placing pre-existing software components together, it is possible to create a complete application. Such components provide interfaces so that programs use them for their intended purposes. The objective of this thesis is to illustrate how software components work together to make a complete application. To illustrate the ideas and the components, this project presents a three-tiered web database application. This application, as a whole, is made up of the client side web browser, a database and the actual application programs which are Java …

Web-Based Interlibrary Loan System, Ee Peng Lim, Schubert Foo, Cheng Hai Tan, Kwang-Yong Tan

Research Collection School Of Computing and Information Systems

Interlibrary loan (ILL) system is one of the important library services provided by most public libraries. Through ILL, public libraries share their collections of reading material and library users are able to access library resources beyond their affiliated libraries. However, the present manual ILL process is inconvenient, inefficient and error-prone. In this project, we developed a system that automated many tedious procedures in the existing ILL system. The new ILL system is realized by a number of Java applets customized for librarians and library users. The new ILL system allows library users to submit ILL requests at any time using …

Investigations Of A Phenanthroline-Based Azo Dye Ligand And Of Re(I) And Ru(Ii) Complexes Based On This Ligand, Yan Zhang

Masters Theses

A 1,10-phenanthroline based azo dye ligand, phen-azo-phenol, produced by diazotizing 5-amino-1,10-phenanthroline (5-NH₂-phen) and then coupling to phenol, and several transition metal complexes containing this ligand, have been synthesized and characterized. The phen-azo-phenol ligands attach to Re(I) and Ru(II) through the phenanthroline linkage to form stable polypyridyl complexes. These complexes show greatly enhanced absorption properties in the visible region when compared to the well-known analogous bipyridine and phenanthroline containing complexes. The visible light absorption of the free ligand and the complexes containing this ligand are greatly affected by the position of the deprotonation equilibrium of the -OH group on …

Canonical Framings For 3 -Manifolds, Rob Kirby, Paul Melvin

Turkish Journal of Mathematics

No abstract provided.

Seiberg-Witten Invariants Of Mapping Tori,Symplectic Fixed Points, And Lefschetz Numbers, Dietmar A. Salamon

Turkish Journal of Mathematics

No abstract provided.