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Cyanide Assimilation in Pseudomonas Fluorescens: Characterization of Cyanide Oxygenase as a Pterin-Dependent Multicomponent Enzyme Complex

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Cyanide utilization in Pseudomonas fluorescens NCIMB 11764 occurs via oxidative conversion to carbon dioxide and ammonia, the latter satisfying the nitrogen requirement. Substrate attack is initiated by an enzyme referred to as cyanide oxygenase (CNO), previously shown to require components in both high (H) (>30 kDa) and low (L) (<10 kDa) molecular weight cell fractions. In this study, tetrahydrobiopterin (H4biopterin) was identified as a cofactor in fraction L, thus making CNO appear as a pterin- dependent hydroxylase. CNO was purified 150-fold (specific activity 0.9 U/mg) and quantitatively converted cyanide to formate and ammonia as reaction products. When coupled with formate dehydrogenase, the complete enzymatic system for cyanide oxidation to carbon dioxide and ammonia was reconstituted. CNO was found to be an aggregate of known enzymes that included NADH oxidase (Nox), NADH peroxidase (Npx), cyanide dihydratase (CynD) and carbonic anhydrase (CA). A complex multi-step reaction mechanism is proposed in which Nox generates hydrogen peroxide which in turn is utilized by Npx to catalyze the oxygenation of cyanide to formamide accompanied by the consumption of one and two molar equivalents of oxygen and NADH, respectively. The further hydrolysis of formamide to ammonia and formate is thought to be mediated by CynD. The …
Date: May 2004
Creator: Fernandez, Ruby
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Passivation effects of surface iodine layer on tantalum for the electroless copper deposition.

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The ability to passivate metallic surfaces under non-UHV conditions is not only of fundamental interests, but also of growing practical importance in catalysis and microelectronics. In this work, the passivation effect of a surface iodine layer on air-exposed Ta for the copper electroless deposition was investigated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Although the passivation effect was seriously weakened by the prolonged air exposure, iodine passivates the Ta substrate under brief air exposure conditions so that enhanced copper wetting and adhesion are observed on I-passivated Ta relative to the untreated surface.
Date: May 2004
Creator: Liu, Jian
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Pedagogical style and influence of Nadia Boulanger on music for wind symphony, an analysis of three works by her students: Copland, Bassett, and Grantham.

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An examination of the influences on twentieth-century wind music would be incomplete without the consideration of composer, organist, pianist, conductor, teacher, and critic Nadia Boulanger (1887-1979). Students from the United States began studying with Boulanger between World War I and World War II, and continued to travel to study with her for over fifty years. The respect awarded this legendary French woman was gained as a result of her effectiveness as a teacher, her influence on the development of each student's unique compositional style, and her guidance of an emerging American musical style. The correlation between the teacher's lessons and the compositional output of her students must be explored. Boulanger did not compose specifically for winds, and she did not encourage her students to compose for the wind symphony. However, this document will outline the influence that this powerful pedagogue exerted over the creation of repertoire by her students by providing insight into the pedagogical style and philosophical foundations of Boulanger as reflected in the literature and by the writings, comments, and compositions of three successful students who composed literature for the wind symphony: Aaron Copland (1900-1990), Leslie Bassett (b. 1923), and Donald Grantham (b. 1947). Three significant works for …
Date: May 2004
Creator: McCallum, Wendy M.
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Supplemental Studies for Mastering Extended Techniques in Three Late Twentieth-Century Works for Solo Trombone: Luciano Berio's Sequenza V, Folke Rabe's Basta and Mark Phillips' T. Rex, Together with Three Recitals of Selected Works by Wagenseil, Grøndahl, Gotkovsky, and Others

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Many, if not most, student trombonists have perhaps had little or no previous experience with "extended techniques"-novel or unconventional modes of sound production. To address this deficiency of experience, this document sets forth a progressive sequence of descriptive explanations and supplementary studies, which are specifically designed to assist trombonists in mastering the particular extended techniques that will prepare them to perform three of the most popular late Twentieth-Century pieces for trombone that include extended techniques-Luciano Berio's Sequenza V, Folke Rabe's Basta, and Mark Phillips' T.Rex. Following the introductory chapter, the body of the document consists of three chapters, each of which deals with one of the three solos, presenting descriptive explanations of relevant extended techniques interspersed with performance commentary (solicited from prominent trombonists) and supplementary studies (composed by the author). The studies presented in each chapter are specifically geared toward mastering the extended techniques as they relate to the music of each particular solo. They are also especially focused toward learning the more difficult passages of music in each solo.
Date: May 2004
Creator: Scott, Deb
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Richard Strauss's Duett-Concertino: A Study of the Programmatic Elements for the Performer

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Richard Strauss's Duett-Concertino for Clarinet and Bassoon with Strings and Harp, AV 147 was one of the last works written by this celebrated composer. This double concerto has been largely unrecognized by performers and scholars until a recent surge in recorded performances. Some factors that hinder performances of the Duett-Concertino include unusual scoring and difficult rhythmic passages, as well as a lack of acknowledgement or understanding of the programmatic elements represented in the music. Sketches and letters show that the Duett-Concertino was inspired by a fairytale, which may have been the popular Beauty and the Beast. The programmatic analysis in this study examines the musical gestures of the piece, which, when combined with the cues provided in the sketches and letters, construct a musical interpretation of the fairytale. Recognition of the extra-musical features of the Duett-Concertino is essential for an effective performance and, in turn, creates additional performance possibilities such as narration and choreography.
Date: May 2004
Creator: Turley, Sarah Leigh
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Synthesis of cubic boron nitride thin films on silicon substrate using electron beam evaporation.

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Cubic boron nitride (cBN) synthesis has gained lot of interest during the past decade as it offers outstanding physical and chemical properties like high hardness, high wear resistance, and chemical inertness. Despite of their excellent properties, every application of cBN is hindered by high compressive stresses and poor adhesion. The cost of equipment is also high in almost all the techniques used so far. This thesis deals with the synthesis of cubic phase of boron nitride on Si (100) wafers using electron beam evaporator, a low cost equipment that is capable of depositing films with reduced stresses. Using this process, need of ion beam employed in ion beam assisted processes can be eliminated thus reducing the surface damage and enhancing the film adhesion. Four sets of samples have been deposited by varying substrate temperature and the deposition time. scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) techniques have been used to determine the structure and composition of the films deposited. X-ray diffraction (XRD) was performed on one of the samples to determine the thickness of the film deposited for the given deposition rate. Several samples showed dendrites being formed as …
Date: May 2004
Creator: Vemuri, Prasanna
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Electrodeposition of adherent copper film on unmodified tungsten.

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Adherent Cu films were electrodeposited onto polycrystalline W foils from purged solutions of 0.05 M CuSO4 in H2SO4 supporting electrolyte and 0.025 M CuCO3∙Cu(OH)2 in 0.32 M H3BO3 and corresponding HBF4 supporting electrolyte, both at pH = 1. Films were deposited under constant potential conditions at voltages between -0.6 V and -0.2 V vs Ag/AgCl. All films produced by pulses of 10 s duration were visible to the eye, copper colored, and survived a crude test called "the Scotch tape test", which stick the scotch tape on the sample, then peel off the tape and see if the copper film peels off or not. Characterization by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray photon spectroscopy (XPS) confirmed the presence of metallic Cu, with apparent dendritic growth. No sulfur impurity was observable by XPS or EDX. Kinetics measurements indicate that the Cu nucleation process in the sulfuric bath is slower than in the borate bath. In both baths, nucleation kinetics do not correspond to either instantaneous or progressive nucleation. Films deposited from 0.05 M CuSO4/H2SO4 solution at pH > 1 at -0.2 V exhibited poor adhesion and decreased Cu reduction current. In both borate and sulfate baths, small …
Date: May 2004
Creator: Wang, Chen
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Study of Conductance Quantization by Cross-Wire Junction

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The thesis studied quantized conductance in nanocontacts formed between two thin gold wires with one of the wires coated by alkainthiol self assembly monolayers (SAM), by using the cross-wire junction. Using the Lorenz force as the driving force, we can bring the two wires in contact in a controlled manner. We observed conductance with steps of 2e2 / h. The conductance plateaus last several seconds. The stability of the junction is attributed to the fact that the coating of SAM improves the stability and capability of the formed contact.
Date: May 2004
Creator: Zheng, Tao
Object Type: Thesis or Dissertation
System: The UNT Digital Library

Carbon Nanotube/Microwave Interactions and Applications to Hydrogen Fuel Cells.

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One of the leading problems that will be carried into the 21st century is that of alternative fuels to get our planet away from the consumption of fossil fuels. There has been a growing interest in the use of nanotechnology to somehow aid in this progression. There are several unanswered questions in how to do this. It is known that carbon nanotubes will store hydrogen but it is unclear how to increase that storage capacity and how to remove this hydrogen fuel once stored. This document offers some answers to these questions. It is possible to implant more hydrogen in a nanotube sample using a technique of ion implantation at energy levels ~50keV and below. This, accompanied with the rapid removal of that stored hydrogen through the application of a microwave field, proves to be one promising avenue to solve these two unanswered questions.
Date: May 2004
Creator: Imholt, Timothy James
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Density, Distribution and Habitat Requirements for the Ozark Pocket Gopher (Geomys Bursarius Ozarkensis) (open access)

Density, Distribution and Habitat Requirements for the Ozark Pocket Gopher (Geomys Bursarius Ozarkensis)

A new subspecies of the plains pocket gopher (Geomys bursarius ozarkensis), located in the Ozark Mountains of north central Arkansas, was recently described by Elrod et al. (2000). Current range for G. b. ozarkensis was established, habitat preference was assessed by analyzing soil samples, vegetation and distance to stream and potential pocket gopher habitat within the current range was identified. A census technique was used to estimate a total density of 3, 564 pocket gophers. Through automobile and aerial survey 51 known fields of inhabitance were located extending the range slightly. Soil analyses indicated loamy sand as the most common texture with a slightly acidic pH and a broad range of values for other measured soil parameters and 21 families of vegetation were identified. All inhabited fields were located within an average of 107.2m from waterways and over 1,600 hectares of possible suitable habitat was identified.
Date: May 2004
Creator: Kershen, Audrey Allbach
Object Type: Thesis or Dissertation
System: The UNT Digital Library
IPCC Expert Meeting on The Science to Address UNFCCC Article 2 including Key Vulnerabilities (open access)

IPCC Expert Meeting on The Science to Address UNFCCC Article 2 including Key Vulnerabilities

This report contains supporting material to examine the science relating to stabilizing greenhouse gas concentrations at a level that would prevent dangerous anthropogenic interference. The report was prepared for consideration by the IPCC, but it has not been subjected to formal IPCC review processes.
Date: May 2004
Creator: Intergovernmental Panel on Climate Change
Object Type: Text
System: The UNT Digital Library
Texas Jewish Post (Fort Worth, Tex.), Vol. 58, No. 19, Ed. 1 Thursday, May 6, 2004 (open access)

Texas Jewish Post (Fort Worth, Tex.), Vol. 58, No. 19, Ed. 1 Thursday, May 6, 2004

Weekly Jewish newspaper from Fort Worth, Texas that includes local, state, and national news along with extensive advertising.
Date: May 6, 2004
Creator: Wisch, Rene & Wisch-Ray, Sharon
Object Type: Newspaper
System: The Portal to Texas History
Texas Jewish Post (Fort Worth, Tex.), Vol. 58, No. 21, Ed. 1 Thursday, May 20, 2004 (open access)

Texas Jewish Post (Fort Worth, Tex.), Vol. 58, No. 21, Ed. 1 Thursday, May 20, 2004

Weekly Jewish newspaper from Fort Worth, Texas that includes local, state, and national news along with extensive advertising.
Date: May 20, 2004
Creator: Wisch, Rene & Wisch-Ray, Sharon
Object Type: Newspaper
System: The Portal to Texas History
Texas Jewish Post (Fort Worth, Tex.), Vol. 58, No. 20, Ed. 1 Thursday, May 13, 2004 (open access)

Texas Jewish Post (Fort Worth, Tex.), Vol. 58, No. 20, Ed. 1 Thursday, May 13, 2004

Weekly Jewish newspaper from Fort Worth, Texas that includes local, state, and national news along with extensive advertising.
Date: May 13, 2004
Creator: Wisch, Rene & Wisch-Ray, Sharon
Object Type: Newspaper
System: The Portal to Texas History
Texas Jewish Post (Fort Worth, Tex.), Vol. 58, No. 22, Ed. 1 Thursday, May 27, 2004 (open access)

Texas Jewish Post (Fort Worth, Tex.), Vol. 58, No. 22, Ed. 1 Thursday, May 27, 2004

Weekly Jewish newspaper from Fort Worth, Texas that includes local, state, and national news along with extensive advertising.
Date: May 27, 2004
Creator: Wisch, Rene & Wisch-Ray, Sharon
Object Type: Newspaper
System: The Portal to Texas History
Yeah, I Found It!: Performing Web Site Usability Testing to Ensure that Off-Campus Students Can Find the Information They Need (open access)

Yeah, I Found It!: Performing Web Site Usability Testing to Ensure that Off-Campus Students Can Find the Information They Need

This paper discusses the results of the formal usability studies and focus groups that involved other libraries' web pages to to first determine what users appreciated or disliked about the current site. This article was co-published in The Eleventh Off-Campus Library Services Conference Proceedings.
Date: May 2004
Creator: Thomsett-Scott, Beth
Object Type: Article
System: The UNT Digital Library
South Texas Catholic (Corpus Christi, Tex.), Vol. 39, No. 9, Ed. 1 Friday, May 7, 2004 (open access)

South Texas Catholic (Corpus Christi, Tex.), Vol. 39, No. 9, Ed. 1 Friday, May 7, 2004

Semi-monthly newspaper from Corpus Christi, Texas published by the Diocese of Corpus Christi that includes news of interest to Diocese members along with advertising.
Date: May 7, 2004
Creator: Goldapp, Paula J.
Object Type: Newspaper
System: The Portal to Texas History
South Texas Catholic (Corpus Christi, Tex.), Vol. 39, No. 10, Ed. 1 Friday, May 21, 2004 (open access)

South Texas Catholic (Corpus Christi, Tex.), Vol. 39, No. 10, Ed. 1 Friday, May 21, 2004

Semi-monthly newspaper from Corpus Christi, Texas published by the Diocese of Corpus Christi that includes news of interest to Diocese members along with advertising.
Date: May 21, 2004
Creator: Goldapp, Paula J.
Object Type: Newspaper
System: The Portal to Texas History
Hudspeth County Herald and Dell Valley Review (Dell City, Tex.), Vol. 48, No. 39, Ed. 1 Friday, May 28, 2004 (open access)

Hudspeth County Herald and Dell Valley Review (Dell City, Tex.), Vol. 48, No. 39, Ed. 1 Friday, May 28, 2004

Weekly newspaper from Dell City, Texas that includes local, state, and national news along with advertising.
Date: May 28, 2004
Creator: Lynch, Mary Louise
Object Type: Newspaper
System: The Portal to Texas History
Hudspeth County Herald and Dell Valley Review (Dell City, Tex.), Vol. 48, No. 37, Ed. 1 Friday, May 14, 2004 (open access)

Hudspeth County Herald and Dell Valley Review (Dell City, Tex.), Vol. 48, No. 37, Ed. 1 Friday, May 14, 2004

Weekly newspaper from Dell City, Texas that includes local, state, and national news along with advertising.
Date: May 14, 2004
Creator: Lynch, Mary Louise
Object Type: Newspaper
System: The Portal to Texas History
Hudspeth County Herald and Dell Valley Review (Dell City, Tex.), Vol. 48, No. 38, Ed. 1 Friday, May 21, 2004 (open access)

Hudspeth County Herald and Dell Valley Review (Dell City, Tex.), Vol. 48, No. 38, Ed. 1 Friday, May 21, 2004

Weekly newspaper from Dell City, Texas that includes local, state, and national news along with advertising.
Date: May 21, 2004
Creator: Lynch, Mary Louise
Object Type: Newspaper
System: The Portal to Texas History
Hudspeth County Herald and Dell Valley Review (Dell City, Tex.), Vol. 48, No. 36, Ed. 1 Friday, May 7, 2004 (open access)

Hudspeth County Herald and Dell Valley Review (Dell City, Tex.), Vol. 48, No. 36, Ed. 1 Friday, May 7, 2004

Weekly newspaper from Dell City, Texas that includes local, state, and national news along with advertising.
Date: May 7, 2004
Creator: Lynch, Mary Louise
Object Type: Newspaper
System: The Portal to Texas History