The first committed step in DNA biosynthesis occurs by direct reduction of
ribonucleotides. This reduction is catalyzed by ribonucleotide reductase (RNR), an
enzyme which uses a unique radical mechanism to facilitate the transformation. All four
DNA precursors are synthesized by a single enzyme. Therefore, an intricate pattern of
regulation has...
The discovery of the methylerythritol phosphate pathway (the MEP pathway) as an alternate pathway for isoprenoid biosynthesis in some organisms including most bacteria, malarial parasites and plants, but not in animals, has stimulated extensive studies in this area. Research has revealed the potential of finding novel antibacterials, antimalarial drugs, and...
This dissertation describes studies of isoprenoid biosynthesis in the
phytoflagellate Euglena gracilis. Elucidation of a novel isoprerioid pathway, the 2-Cmethyl-D-erythritol-4-phosphate (MEP) pathway, in addition to the generally known
mevalonate (MVA) pathway, led to extensive exploration of the distribution of both pathways in a variety of organisms. To date, photosynthetic eukaryotes...
The loss of all deuterium labels from previous feedings of [2-²H]-,
[3,3-²H₂]-, and [2,3,3-²H₃]arginines had indicated the possible intermediacy
of β-hydroxy- and β-ketoarginine (30 and 31, respectively) in the
biosynthesis of the streptolidine portion of streptothricin F (la).
In order to confirm or refute this evidence, D,L-[2,3,3,5,5-²H₅]-
arginine (32) was...
The testing of nuclear fuel under reactivity-initiated accident (RIA) conditions is paramount for the better understanding of the fuel’s behavior during this transient accident events. The Transient Reactor Test (TREAT) facility is a nuclear reactor that will be capable of recreating the thermal-hydraulic and neutronic boundary conditions representative of RIA...
This study was conducted in the old-growth forests of Clatsop,
Tillamook, and Lincoln counties, Oregon. The three objectives of
the research were to describe and classify the near-climax plant
communities found within the forests, to relate the associes described
by a previous study to the forest communities characterized by the...
An enhanced swing differential Colpitts VCO (ESDC-VCO) dramatically improves
the swing of a Colpitts VCO by allowing the signal to swing below ground and above the
supply voltage. Fabricated in a 1P8M 0.13 um CMOS process, the ESDC-VCO operates
at 4.9GHz with a 0.475-V supply and consumes 2.7mW. The measured...
In the highly alkaline environment of concrete, carbon steel rebar is protected against corrosion by a passive oxide/oxyhydroxide film. Understanding the characteristics of this passive film, and how it depassivates, is the key for mitigating problems associated with steel corrosion in concrete. Although a large number of electrochemical and analytical...
The purpose of this research was to determine if there were
initial differences in selected dimensions of self-actualization, as
measured by the Personal Orientation Inventory (POI), between the
freshmen who selected co-educational residence halls and those who
selected single-sex residence halls; and to determine if the type
of residence hall...
As the fifth generation of mobile communication systems (5G) is being deployed, massive multiple-input multiple-output (MIMO) serves as one of its enabling technologies where reliable and ultra low latency communications are achieved while being power and spectrum efficient. This thesis studies the security aspect of massive MIMO system from the...