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Aspects of the manganese nutrition of lupins : redistribution of accumulated manganese and the diagnosis, prognosis and prevention of manganese deficiencyHannam, R. J. (Robert James) January 1984 (has links) (PDF)
Mounted ill. Offprint of the author's journal article in pocket. Includes bibliographies.
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Developmental axial skeletal deformities : baseline study with a zebrafish modelHarden, Jon M. 23 September 2003 (has links)
The aim of this study was to assess sensitivity of early life stage zebrafish to
cadmium (Cd). Embryos and larva were exposed to Cd before the formation of
skeletal elements. Exposure times were selected to determine whether Cd
perturbed developmental processes that lead to skeletal deformities, and to
characterize the types of skeletal deformities that occurred. Embryo/larva were
exposed to 3μM, 10μM, 30μM, 100μM, 300μM, and 1000μM Cd at 12-36 hours
post fertilization (hpf), 36-60hpf, 60-84hpf, and 144-168hpf in one series of
experiments. This experiment was conducted at circumneutral pH. A second series
of experiments with these same Cd concentrations were also conducted at pH 6
with embryo/larva exposed at 12-36hpf, 36-60hpf, and 60-84hpf. The fish that
survived the exposures were raised for 40-60 days whereupon the surviving fish
were overdosed with MS222, and X-rayed. The later early life stage fish were
more sensitive to Cd toxicity; the chorion appeared to protect the earlier exposed
embryos (zebrafish hatch 48-72hpf). Embryo/larva were more resistant to toxicity
from dissolved Cd (pH 6) than particulate Cd (circumneutral pH); absence of
functional gills during early life stages perhaps explained resistance to dissolved
Cd. Notochord lesions (typically lethal within two weeks) occurred when embryos
were exposed 12-36hpf. There was no evidence for sensitivity of early life stage
zebrafish to Cd induced skeletal deformities that occurred within 40-60 days of Cd
exposures. / Graduation date: 2004
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Acute bioactivation and hepatotoxicity of ketoconazole in rat and the determinant presence of flavin-containing monooxygenase (FMO) isoforms in human duodenum, jejunum, ileum, and colon microsomes and Caco-2 cell lineBuckholz, Cheryl J. 19 May 2003 (has links)
Two specific goals were addressed for this dissertation. First to investigate
and identify the mechanistic profile of ketoconazole (KT)-induced hepatotoxicity
by utilizing in vivo and in vitro approaches determining the mechanism of action
for the hepatotoxicity incurred. To date, there has not been a mechanistic
determination of the hepatotoxicity associated with KT in vivo. This dissertation
evaluates the possible metabolic bioactivation of KT by cytochrome-P450 (CYP)
or flavin-containing monooxygenases (FMO) resulting in covalent binding with
hepatic macromolecules. The hypothesis of this study was to reveal whether
covalent binding by the parent compound, KT, and/or reactive metabolites
produces hepatic damage associated with increased serum alanine
aminotransaminase (ALT) release and decreased hepatic glutathione (GSH). The
first objective was determination of in vivo covalent binding in a dose-time
response comparison in Sprague-Dawley (SD) rat ALT and GSH levels. Increased
ALT and reduced hepatic GSH levels occurred. The second objective was an in
vitro comparison of covalent binding with GSH levels utilizing SD microsomal
protein with incubations of KT. Covalent binding decreased with added GSH to
microsomal incubations. Thirdly, correlate in vivo with in vitro findings. Covalent
binding of KT in vivo and in vitro occurred with increased doses and time. The
final objective was to determine the bioactivation pathway utilizing heat
inactivation and no NADPH in vitro. Covalent binding of KT decreased in the
absence of NADPH and deactivation of FMO.
The second goal was to determine and quantitate in vitro the presence of
FMO isozymes in microsomes of the human intestinal duodenum, jejunum, ileum,
and colon as well as the Caco-2 (HTB-37), epithelial intestinal (CCL-241) and
colon (CRL1790) cell lines. The presence of FMO could result in a first-pass effect
decreasing the bioavailability of soft nucleophiles or a toxicity effect due to
inhibition or modulation of the enzyme from co-administration. To date, this is the
first evaluation of FMO isoforms in human intestine and cell lines. Western blot
techniques were utilized for detection of human FMO1, FMO3, and FMO5 using
human FMO-expressed recombinant cDNA from a baculovirus system. / Graduation date: 2003
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Molecular and cellular mechanisms of aromatic hydrocarbon axonopathyKim, Min Sun 28 November 2001 (has links)
Hydrocarbon solvents are widely used in the production of paints,
adhesives, dyes, polymers, plastics, textiles, printing inks, agricultural products and
pharmaceuticals. While the neuropathic potential of aliphatic solvents was shown
in the 1970s, little is known about the neuropathic potential of aromatic solvents.
The present study examines such solvents, 1,2-diethylbenzene (DEB) and
its metabolite 1,2-diacetylbenzene (DAB), to determine (a) the neuropathological
evidence for peripheral neuropathy in rodents treated with 1,2-DAB, (b) the
neurochemical basis for the neurotoxic properties of this compound, and (c) the
structural requirements for nerve fiber damage. The properties of 1,2-DAB and 2,5-
hexanedione (HD) are also compared.
A key finding of this thesis is that 1,2-DAB induces a 2,5-HD-like pattern
of nerve damage of motor and sensory axons with focal swellings containing
neurofilaments. Whereas nerve damage begins distally in 2,5-HD intoxication,
with 1,2-DAB treatment axonal swellings begin intraspinally and in the proximal
ventral roots of motor nerve fibers.
A second key finding is the reactivity of 1,2-DAB with amino acids,
notably lysine, a property that is shared with 2,5-HD. 1,2-DAB and 2,5-HD react
with amino acids and proteins to form blue and yellow chromophores, respectively.
Relative to 2,5-HD, 1,2-DAB is three orders of magnitude more reactive in forming
high-molecular-weight species.
1,2-DAB treatment of spinal cord slices in vitro and intact sciatic nerve
in vivo showed that neurofilament proteins react more readily than beta-tubulin.
The heavy and medium subunits of neurofilament protein were more reactive than
the light subunit. The reactivity of these four axonal proteins was in proportion to
their lysine content. These data are consistent with selective accumulation of
neurofilaments in giant axonal swellings.
In summary, these studies have shown a relationship between the
chromogenic and neuropathic properties of two gamma-diketones, one aliphatic
(2,5-HD) the other aromatic (1,2-DAB). These studies are relevant to occupational
and public health for at least two reasons. First, urinary chromogens generated by
neuropathic aliphatic and aromatic hydrocarbons could serve as biological markers
of exposure to solvents with neuropathic potential, and second, other chromogenic
solvents (such as tetralin) should be considered for neuropathic potential. / Graduation date: 2002
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Effects of long-term residue management and nitrogen fertilization on availability and profile distribution of nitrogen, phosphorus, and sulfurChrist, Robert A. 30 June 1992 (has links)
Graduation date: 1993
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Sectoral Effects of Foreign Direct Investment on Host Country Economic Growth: Evidence from Emerging CountriesRahimov, Vugar January 2013 (has links)
In this paper, I study the effect of foreign direct investment (FDI) on a group of host country economic growth for the period 1994-2011. Using aggregate level FDI data for a group of five emerging countries, the paper reveals that FDI has a positive effect on economic growth. Then I use sectoral data and test whether all the sectors have positive effects on growth. The results vary across the sectors. The results seem to be positive for mining and quarrying as well as manufacturing sector, while trade and financial intermediation sectors to have a negative effect on economic growth.
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Cholinergic interneurons and synaptic reorganization within the nucleus accumbens shell and core: potential neural substrates underlying drug addictionBerlanga, Monica Lisa 29 August 2008 (has links)
Not available
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Berry phase related effects in ferromagnetic metal materialsYang, Shengyuan 08 June 2011 (has links)
The concept of Berry phase, since its proposition in 1984, has found numerous applications and appears in almost every branch of physics today. In this work, we study several physical effects in ferromagnetic metal materials
which are manifestations of the Berry phase. We first show that when a domain wall in a ferromagnetic nanowire is undergoing precessional motion, it pumps an electromotive force which follows a universal Josephson-type relation. We discover that the integral of the electromotive
force over one pumping cycle is a quantized topological invariant equal to integer multiples of h/e, which does not depend on the domain wall geometry nor its detailed dynamic evolution.
In particular, when a domain wall in a nanowire is driven by a constant magnetic field, we predict that the generated electromotive force is proportional to the applied field with a simple coefficient consisting of only fundamental constants. Our theoretical prediction has been successfully confirmed by experiments. Similar effect known as spin pumping occurs in magnetic multilayer heterostructures,
where a precessing free magnetic layer pumps a spin current into its adjacent normal metal layers. Based on this effect, we propose two magnetic nanodevices that can be useful in future spintronics applications: the magnetic
Josephson junction and the magneto-dynamic battery. The magnetic
Josephson junction has a drastic increase in resistance when the applied current exceeds a critical value determined by the magnetic anisotropy. The magneto-dynamic battery acts as a conventional charge battery in a circuit with well-defined electromotive force and internal resistance. We investigate the condition under which the power output and efficiency of the battery can be optimized. Finally we study the side jump contribution in the
anomalous Hall effect of a uniformly magnetized ferromagnetic metal. The side jump contribution, although arises from disorder scattering, was believed to be independent of both the scattering strength and the disorder density.
Nevertheless, we find that it has a sensitive dependence on the spin structure of the disorder potential. We therefore propose a classification scheme of disorder scattering according to their spin structures. When two or more classes of disorders are present, the value of side jump is no longer fixed but depends on the relative disorder strength between classes. Due to this competition, the side jump contribution could flow from one class dominated limit to another class dominated limit
when certain system control parameter changes. Our result indicates that the magnon scattering plays a role distinct from the normal impurity
scattering and the phonon scattering in the anomalous Hall effect, because they belong to different scattering classes. / text
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Effect of simulating flooding pattern on nitrogen management in rice (Oryza sativa L.) production.Mulbah, Quaqua Sumo. January 2010 (has links)
Flooding cycle in wetland rice (Oryza sativa L.) production systems is often subject to seasonal and cultural variations which may affect the availability and uptake of nitrogen in different ways. These factors may more or less influence the physiological and growth responses of the plant. In an effort to improve productivity in rice cropping systems, two controlled environment studies and a field trial were conducted to evaluate the growth and yield responses of rice to different flooding regimes and nitrogen fertilizer management strategies. In the first glasshouse trial, an upland cultivar (GM-1) was used to study the effects of four flooding regimes and three nitrogen application rates on the tillering, yield components and grain yield of rice. The field study determined the applicability of the results of the glasshouse trial to out-door environmental conditions, with the aim of gaining further insight into the impact of nitrogen application strategy on tiller and grain qualities. Two wetland cultivars (FKR-19 and N-19) and GM-1 were used to evaluate the effects of two flooding regimes and two nitrogen topdressing patterns. The second glasshouse trial determined the effect of hydro-priming on the establishment of direct seeded rice, and the effect of flooding on aerenchyma formation in rice roots. Results of the studies showed that flooding with standing water of 5 cm above the soil surface, irrespective of when it occurred, and nitrogen application increased the number of tillers and panicles, above ground dry matter, nitrogen uptake and grain yield of rice. However, late flooding and high nitrogen application rate of 220 kg ha-1 were found to encourage the production of late tillers, thereby reducing the efficiency of nitrogen use for grain production. Nitrogen application in three split doses tended to increase plant nitrogen content at heading; it slightly increased the protein content of the grains at maturity, but reduced the amylose content of the starch granules. Nitrogen application in two split doses led to increased grain yield in non-flooded plants, while the three-split treatment increased nitrogen uptake and grain yield in the flooded plants.
Flooding significantly increased aerenchyma formation in the cortical tissues of rice roots, particularly at 50 mm behind the root tips. Hydro-priming seeds for 48 h improved plant establishment by shortening the germination and emergence times, and increasing the
height and dry matter accumulation of seedlings, thereby ameliorating the susceptibility of rice to flooding stress. Overall, the thesis affirmed that controlled flooding is beneficial to rice production since it enhanced the growth and yield of the plant. It further revealed that early flooding and appropriate timing of moderate nitrogen application can ensure the conservation of water and nitrogen resources, including the quality of the environment, with no significant consequence for yield and productivity of the crop. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.
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Physical, chemical and biological factors affecting the survival of fingernail clams in pool 8, upper Mississippi RiverDePoy, Richard Mark January 1996 (has links)
1 examined the temporal and spatial distribution of total ammonia nitrogen (TAN) and un-ionized ammonia (NH,) in sediment pore water and compared the temporal and spatial patterns of TAN and NH, in overlying surface water with those in pore water, to determine if they were reaching concentrations known to be deleterious to fingernail clams. Pore water was obtained by core extraction and subsequent centrifugation. TAN and NI-I3 in pore water were measured from May through December 1994, at ninety two sites in pool 8, upper Mississippi River, to a depth of five centimeters below the sediment-water interface. TAN and NH3 in pore water were significantly different among sampling dates; with the greatest concentrations occurring in the summer months. Tan and N1-I3 in pore water was significantly greater in impounded open water and backwater side channel habitats and least in main channel border habitat. Tan and NH3 in surface water were significantly less than those in pore water from all of the habitats studied. Analysis of sediment substrate physical features, found that fingernail clam density and occupance were correlated to texture, with fingernail clams preferring silt loam and loam textures. Analysis of the data determined fingernail clams have a preference for particular water depths. It was found that a positive correlation exists between the occurrence and abundance of may flies and fingernail clams. Additionally, this study found a positive correlation between the density of dead fingernail clams (as per empty shells) and the abundance of live fingernail clams. Sites that contained a mean NI-I, concentration below 36 ug/L possessed the largest numbers of fingernail clams. When the mean un-ionized ammonia was above 36 ug/l, fingernail clam density declined precipitously-- 36 ug/L NH3 is the concentration demonstrated to inhibit growth of fingernail clams in laboratory studies. Mean concentrations of NH, in pore water at sites containing fingernail clams was 40 ug/L and ranged from 3 to 100 ug/L. At sites where fingernail clams were nonexistent, NH3 ranged from 3 to 375 ug/L with a mean of 57 ugfL. Mean un-ionized ammonia concentrations at sites containing fingernail clams were significantly different from and consistently lower than sites without fingernail clams. / Department of Natural Resources and Environmental Management
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