UNT Theses and Dissertations - 857 Matching Results

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The Incidence of Escherichia Coli and other Coliform Organisms on Seventy-One Samples of Fresh Fruits and Vegetables Purchased from Eight Grocery Stores in Denton, Texas

Description: This investigation has for its aim the explanation of the incidence of colon bacteria on a number of food samples purchased in grocery stores of Denton, Texas, by an analysis of correlative sanitary factors.
Date: 1945
Creator: Scoggin, Frances Grammar
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Incubation humidity as an environmental stressor on the osmoregulatory developmental program of the chicken, Gallus gallus domesticus.

Description: Fetal programming results from stressors during fetal development and may influence the occurrence of disease later in life. Maternal nutritional status and/or environment can affect renal development by inducing limited nephron endowment at birth, which results in diseases such as hypertension and coronary heart disease in mammals. Birds are likely to be effective models for this process because, like mammals, they have high pressure cardiovascular systems, mammalian-type nephrons and are ho… more
Date: August 2009
Creator: Bolin, Greta M.
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Individual, Social, and Seasonal Behavior of the Thirteen-Lined Ground Squirrel (Spermophilus tridecemlineatus)

Description: The purpose of this study is to provide a qualitative, detailed description of individual and social behavior in a free-living population of thirteen-lined ground squirrels. Behavioral differences in relation to various periods of the annual cycle are also evaluated.
Date: January 1970
Creator: Wistrand, Harry E.
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Induced Bradycardia Effects on Angiogenesis, Growth and Development in Early Development in Chicken Embryos, Gallus Domesticus

Description: Cardiac performance, angiogenesis and growth was investigated during early chicken development. Heart rate, and thus arterial pulse pressure and cardiac output, were altered with the bradycardic drug ZD7288. Heart rates at 72 h of development of control embryos and those dosed with chicken Ringer were not different at 171 bpm. Acute and chronic application of ZD7288 caused significant bradycardia. Chronic dosing of Ringer and ZD7288 changed neither eye diameter nor development rate. Chronic dos… more
Date: December 2010
Creator: Ruck, Sylvia A.
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Induction of 16α Hydroxylase in Human Cultured Lymphocytes

Description: A method is presented for 160hydroxylase (SAH) induction in cultured human lymphocytes. SAH, a microsomal-associated enzyme, effects the oxidative conversion of 17pestradiol to estriol, which competes for cytoplasmic binding sites. 17,-estradiol and estrone are known mammary carcinogens, while estriol and its epimers have been suggested to have anticarcinogenic properties. To substantiate genetic variations of hydroxylase activity, an analysis of estrogen-induced cultured human lymphocytes was … more
Date: December 1975
Creator: Muijsson, Ingrid E.
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Induction of Aryl Hydrocarbon Hydroxylase in Ambystoma tigrinum

Description: Aryl hydrocarbon hydroxylase (AHH) was induced 15-fold in Ambystoma tigrinum by intraperitoneal injection of 3-methylcholanthrene in corn oil, or 10-fold by addition of aromatic polycyclic hydrocarbons to the aqueous environment of the neotene animal. The cytochrome P-450-associated microsomal enzyme is similar to the inducible, one-gene, autosomal-dominant system typical in the laboratory mouse and man. Differences in optimal temperature for enzyme induction and activity were noted in organ cu… more
Date: December 1974
Creator: Colvin, David P.
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Induction of Visible Mutations in Mormoniella by Use of Low Frequency Ultrasonic Energy

Description: Low-frequency ultrasonic energy was utilized in an attempt to induce visible mutations in the parasitoid wasp Mormoniella vitripennis. This study demonstrates that low frequency ultrasound may be used as an effective mutagenic agent in this organism, and suggests that it may have applications to other genetic systems.
Date: August 1972
Creator: Grubbs, Steven C.
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Inferring a Network of Horizontal Gene Flow among Prokaryotes Using Complementary Approaches

Description: Horizontal gene transfer (HGT), a mechanism that facilitates exchange of genetic material between organisms from different lineages, has a profound impact on prokaryotic evolution. To infer HGT, we first developed a comparative genomics-based tool, APP, which can perform phyletic pattern analysis using completely sequenced genomes to identify genes are unique to a genome or have sporadic distribution in its close relatives. Performance assessment against currently available tools on a manually … more
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Date: August 2022
Creator: Sengupta, Soham
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The Influence of a Return of Native Grasslands upon the Ecology and Distribution of Small Rodents in Big Bend National Park

Description: In the southwestern United States there is a delicate balance between the existing grasslands and the rodent fauna. The purpose of this investigation was to determine the influence of secondary succession of native grasslands upon the ecology and distribution of small rodents. Two methods of determining the rodent species were plot quadrates and trap lines using Sherman live traps.
Date: August 1971
Creator: Baccus, John T.
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Influence of copper on resistance of Lumbricus terrestris to bacterial challenge

Description: Earthworms, Lumbricus terrestris, were challenged orally and intracoelomically with two bacterial species, Aeromonas hydrophila and Pseudomonas aeruginosa, and mortality rates were observed. Neither were found to be particularly pathogenic at injected doses of up to 108 bacteria per earthworm. The influence of Cu++ (as CuSO4) on the earthworm's response to bacterial challenge was investigated by exposing earthworms to sublethal levels of Cu++ prior to bacterial challenge. Exposure at subletha… more
Date: August 2000
Creator: Simmons, Carla Stull
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Influence of Hypoxia on Acute Lead Toxicity and Calcium Homeostasis in Early Life Stage Zebrafish (Danio rerio)

Description: The purpose of this study was to investigate the effects of Pb and hypoxia co-exposure on Pb toxicity and Ca homeostasis in early life stage (ELS) zebrafish (Danio rerio). Previous evidence indicates that exposure of ELS zebrafish to hypoxia (~20% air saturation) reduces Ca uptake, likely through down-regulation of the apical epithelial Ca channel (ECaC). Considering that Pb and Ca are known antagonists and compete for uptake pathways, it was hypothesized that co-exposure of Pb with hypoxia wou… more
Date: December 2021
Creator: Moghimi, Mehrnaz
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The Influence of in Vitro Gill and Liver Metabolism of Xenobiotics on Fish Bioconcentration

Description: This dissertation examines the ability of in vitro biotransformation assays to provide an indication of metabolic potential. The potential for xenobiotic compounds to bioconcentrate in aquatic organisms is expressed through the bioconcentration factor (BCF). The metabolic loss of ibuprofen, norethindrone and propranolol was measured using rainbow trout (Oncorhynchus mykiss) and channel catfish (Ictalurus punctatus) gill and liver S9 fractions, microsomes and cell suspensions. Metabolic trans… more
Date: August 2010
Creator: Gomez, Cristi Frasier
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Influence of parental swimming stamina on the cardiac and metabolic performance of larval zebrafish (Danio rerio).

Description: Superior swimming stamina in adult fish is presumably passed on to their offspring, but the ontogeny of the appearance of superior stamina and the requisite enhanced cardio-respiratory support for locomotion in larval fishes has not been determined. Is the expression of the suite of parental traits enabling superior swimming stamina in their offspring dependent upon their achieving juvenile/adult morphology, or does it appear earlier in their larvae? To answer this, adults were classified int… more
Date: May 2007
Creator: Gore, Matthew R.
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Influence of stormwater drainage facilities on mosquito communities within the city of Denton, Texas.

Description: Weekly collections were conducted from May to December, 2007 (153 trap nights, total) in Denton, Texas, in and around large storm drains and overpass drainage facilities in residential and non-residential areas, using Centers for Disease Control (CDC) light traps and gravid traps. A total of 1964 mosquitoes were collected, representing 24 species within 6 genera: Aedes, Anopheles, Culiseta, Culex, Psorophora, and Uranotaenia. Culex was the most abundant genus, representing 75% of all mosquitoes… more
Date: December 2008
Creator: Kavanaugh, Michael David
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The Influence of Stream Regulation on Genic Differentiation and Thermal Tolerance in the Red Shiner, Notropis Lutrensis

Description: Genetic variation and thermal tolerance were surveyed for variation attributed to nonuniform selection pressures for five populations of the red shiner, Notropis lutrensis, collected from regulated and unregulated portions of a Texas river. Populations within 30 km of a hypolimnion-release dam that experience large thermal perturbations were found to have higher levels of heterozygosity, higher levels of polymorphism, significantly depressed levels of upper thermal tolerance endpoints, and grea… more
Date: December 1982
Creator: King, Timothy L. (Timothy Lee)
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The Inheritance of Serum Alkaline Phosphatase in the Pigeon (Columba livia)

Description: The purpose of this work was to determine the manner of inheritance of serum alkaline phosphatase in the racing pigeon, (Columba livia). The evidence indicates that the electrophoretic patterns of serum alkaline phosphatase in the pigeon are inherited as codominant genes.
Date: August 1968
Creator: Manley, James H., Jr.
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The Inhibition of Fungal Contaminants in Cultures of Mycobacterium Tuberculosis

Description: The problem of conatmination in culture media for Mycobacterium tuberculosis has not been solved completely, and for this reason the work herein presented was carried out. In this work experiments were made testing the effect of actidione in inhibiting certain ones of the higher fungi.
Date: 1951
Creator: Wright, Noble M.
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Inquiry-based science for high school students: a forensic unit

Description: This project constitutes an instructional unit for honors biology that involves the use of science in the field of criminal investigation and forensics. Before beginning the unit, the learners should have mastered basic laboratory skills, including use of the microscope. They should also have an understanding of the basic structure and function of DNA and its role in heredity and protein synthesis. The standard time frame is 24 days with 70-minute periods, but can be easily adjusted to meet cla… more
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Date: August 2000
Creator: Apple, Kendra Kea
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Integrating Concepts in Modern Molecular Biology into a High School Biology Curriculum

Description: More so than any other science in the past several decades, Biology has seen an explosion of new information and monumental discoveries that have had a profound impact on much more than the science itself. Much of this has occurred at the molecular level. Many of these modern concepts, ideas, and technologies, as well as their historical context, can be easily understood and appreciated at the high school level. Moreover, it is argued here that the integration of this is critical for making bio… more
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Date: August 2003
Creator: Parker, Timothy P.
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Interactions among Temperature, pH, and Cyfluthrin on Survival of the Fathead Minnow Pimephales promelas

Description: The 96-hr LC50 of cyfluthrin in Pimephales promelas ata temperature of 23*C and a pH of 8 was 1.08 g/L. The toxicity of cyfluthrin was inversely related to temperature and pH. A temperature of 10*C and a pH of 6 significantly decreased the 96-hr LC50 to 0.009 gg/L. Likewise, sublethal exposures to cyfluthrin significantly affected the fathead minnow's ability to tolerate high and low temperatures. Cyfluthrin compromised the fathead minnow's lower temperature tolerance (CTMin) by 60C and the upp… more
Date: December 1991
Creator: Heath, Susan M.
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Interactions between Carotid and Cardiopulmonary Baroreceptor Populations during Dynamic Exercise in Man

Description: During dynamic exercise the arterial baroreflexes have been thought to reset to the prevailing level of systemic pressure in order to modulate transient changes in blood pressure with the same sensitivity (gain) as at rest. To test this hypothesis, cardiovascular responses to dynamic exercise and carotid baroreflex responses to graded neck suction and neck pressure (NS/NP) were examined in seven men of moderate fitness (V02 = 41.4±3.6 ml O2*kg^-1*min^-1) during two levels (20% and 40% of peak o… more
Date: May 1993
Creator: Potts, Jeffrey Thomas
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Interactions between Carotid and Cardiopulmonary Baroreceptor Populations in Men with Varied Levels of Maximal Aerobic Power

Description: Reductions in baroreflex responsiveness have been thought to increase the prevalence of orthostatic hypotension in endurance trained athletes. To test this hypothesis, cardiovascular responses to orthostatic stress, cardiopulmonary and carotid baroreflex responsiveness, and the effect of cardiopulmonary receptor deactivation on carotid baroreflex responses were examined in 24 men categorized by maximal aerobic power (V02max) into one of three groups: high fit (HF, V0-2max=67.0±1.9 ml•kg^-1•min^… more
Date: August 1989
Creator: Pawelczyk, James A. (James Anthony)
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An Interpretation of Archaic Medical Treatises

Description: Ancient peoples did not distinguish between philosophy, religion, and science. Scientific truth did not exist apart from divine truth. Any new idea, finding, or theory was assimilated into a monolithic mythological structure. This is one of the causes of the underestimation of ancient science: it is always packaged in a myth - the method of preserving information in an oral culture. The mythological medium allowed the preservation and dissemination of hard-won, empirical, scientific knowledge t… more
Date: May 1993
Creator: Wagers, William D. (William Delbert)
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