Detergentes y Biodetergentes en la Biorremediación de Suelo: Inconsistencias y Evidencias (open access)

Detergentes y Biodetergentes en la Biorremediación de Suelo: Inconsistencias y Evidencias

This article analyzes the bioremediation of the soil contaminated by hydrocarbons (HYCOS), the importance of biostimulation with a detergent (DEGE) or biodetergent (BIODET) and the inconsistencies generated by their application.
Date: August 28, 2020
Creator: Saucedo-Martínez, Blanca Celeste; Márquez-Benavides, Liliana; Santoyo-Pizano, Gustavo & Sánchez-Yáñez, Juan Manuel
Object Type: Article
System: The UNT Digital Library
Identification of Glycine as the Factor in Peptone Which Induces Pleomorphism in Azotobacter Vinelandii (open access)

Identification of Glycine as the Factor in Peptone Which Induces Pleomorphism in Azotobacter Vinelandii

The rigid peptidoglycan layer of the cell wall is responsible for maintaining the structural integrity of bacteria. Antibiotics such as penicillin exert their anti-bacterial effect by inhibiting synthesis of peptodoglycan, and enzymes such as lysozyme destroy cell integrity by hydrolyzing specific bonds in the interior of this macromolecule. Defective cells can no longer withstand the high turgor pressure within the cell because they are no longer protected by a rigid wall and tend to become fragile and spherical or irregular in shape. While all bacteria are pleomorphic under certain conditions which do not normally affect other bacteria. This is exemplified by the pleomorphic growth of Azotobacter in nutrient agar or peptone-containing medium. The purpose of this investigation was to study the nature of peptone-induced pleomorphism of Azotobacter. The first phase of study dealt with the effects of poptone on the growth and morphology of A. vinelandii. Many diverse froms were observed in peptone-containing media, but it was shown that all cell types were related to the "fungoid" family of pleomorphic cells. Although Azotobacter failed to accumulate detectable levels of cell-wall precursors in response to glycine treatment, it was shown that glycine acted only on metabolically active cells. In addition, incorporation …
Date: December 1972
Creator: Rosenthal, Raoul Simon
Object Type: Thesis or Dissertation
System: The UNT Digital Library
An Assay Method for Determining Extra-Cellular Lipases from Pseudomonas aeruginosa (open access)

An Assay Method for Determining Extra-Cellular Lipases from Pseudomonas aeruginosa

The applicability of an isotopically labelled assay system to determine the lipase production in Pseudomonas aeruginosa was evaluated. Supernatant from cultures of Pseudomonas aeruginosa grown in a medium containing olive oil was incubated with a substrate containing labelled trioleate. Fatty acids were isolated by means of a liquid-liquid partition system. Enzyme activity was determined by measuring the amounts of free fatty acid by liquid scintillation counting. Findings indicate that the isotopicallylabelled, liquid-liquid partitioning assay is reliable, sensitive and adaptable to rapid assay conditions. It was also determined that different strains of Pseudomonas aeruginosa produce varying amounts of lipase. Partial purification of supernatant by gel filtration produced two protein peaks showing enzymatic activity.
Date: May 1978
Creator: Christensen, John N.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Effects of an Acute Bout of Near-Maximal Intensity Exercise on the Cardiac Enzymes in Human Sera (open access)

Effects of an Acute Bout of Near-Maximal Intensity Exercise on the Cardiac Enzymes in Human Sera

The Cardiac Profile, a pattern of serum enzyme changes seen within seventy-two hours after an AMI, is diagnostic aid for detecting occurrence of infarcts. The effects of exercise stress on the Cardiac Profile aid clinicians in avoiding diagnostic errors in patients immediately after exercise. Five male volunteers ran from six to ten miles. Serum enzyme levels were monitored serially three days before and five days after stress. Enzyme activity was determined spectrophotometrically and electrophoretically. Significant increases in total CPK and LDH were seen. An LDH 'one-two flip' occurred eight hours after exercise. No MB-CPK was found following the run.
Date: May 1979
Creator: Goheen, Bernadette A.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Effect of Operant Behavior on the Metabolism of 5-Hydroxytryptamine (open access)

Effect of Operant Behavior on the Metabolism of 5-Hydroxytryptamine

The role of operant behavior in the metabolism of brain 5-hydroxytryptamine (5-HT) turnover was investigated. Two and one-half hours following the administration of 150 mg/kg of para-chlorophenylalanine (PCPA), a specific inhibitor of tryptophan hydroxylase, levels of 5-HT were compared in sedentary and performing rats. Whole brain levels of serotonin were reduced in both responding and sedentary animals; however, differences between these groups were not statistically significant. The drug induced decrease in 5-HT levels was accompanied by a significant decrease in session responding. The degree of suppressed responding could be correlated with the level of 5-HT following PCPA, suggesting that the metabolism of serotonin is in part modulated by the rate of responding as maintained by the operant schedule.
Date: August 1979
Creator: Shepard, Paul
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Physiology of Azotobacter Vinelandii Cysts (open access)

The Physiology of Azotobacter Vinelandii Cysts

The value of the adenylate energy charge [(ATP)+1/2(ADP)/(ATP)+(ADP)+(AMP)] in Azotobacter vinelandii cells was monitored during growth and germination in flask cultures. The miximal value of 0.88 was attained during mid-log phase; this declined gradually to 0.50 by late stationary phase. When these cultures were transferred to encystment media, the adenylate energy charge decreased to an average value of 0.40 as the vegetative cells encysted and remained unchanged during the next 20 days. Encystment cultures wre composed of vegetative cells, encysting cells and mature cysts but the proportionate value of the energy charge could be assigned. Viability of the total population remained 95% or higher during the entire period studied. Azotobacter vinelandii cysts cultivated on phosphate-sufficient media. Although cell protein and nucleic acids were unaffected by phosphate deficiency, cell wall structures, oxygen uptake and sncystment were significantly affected. Phosphate-limited cysts contained much larger amounts of poly-beta-hydroxybutyric acid but had a lower adenylate energy charge than did control cysts. The ATP/ADP ratio was much lower in phosophate-deficient cysts than in the control cysts. The data indicate a "substrate saving" choice of three metabolic pathways available to cells of Azotobacter under different growth conditions.
Date: December 1980
Creator: Aladegbami, Solomon L.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Some Responses of Bacillus subtilis Spores to Glutaraldehyde (open access)

Some Responses of Bacillus subtilis Spores to Glutaraldehyde

Bacillus subtilis (ATCC 19659) were damaged by exposure to various concentrations of glutaraldehyde, as shown by decreased germination rates. The damage caused was repaired or otherwise obviated by the presence of sodium lactate in the holding medium. When two different salts of lactic acid were compared for ability to overcome the effect of glutaraldehyde, it was found that calcium salt of lactate was more effective than the sodium salt. The damage repair system involved l-alanine, lactate and either the sodium or calcium ions. The study involved in determining the difference in efficiency of spore repair was due to an organic or an amino acii snowed that the presence of two carboxylic functional groups did not effectively alter the reactivity.
Date: May 1985
Creator: Crum, Morris G. (Morris Glenn)
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Radial Compression High Performance Liquid Chromatography as a Tool for The Measurement of Endogenous Nucleotides in Bacteria (open access)

Radial Compression High Performance Liquid Chromatography as a Tool for The Measurement of Endogenous Nucleotides in Bacteria

High performance liquid chromatography was used to measure ribonucleoside triphosphates in microbial samples. Anion exchange columns in a radial compression module were used to separate and quantify purine and pyrimidine ribonucleotides. Endogenous ribonucleoside triphosphates were extracted from Escherichia coli and pseudomonas aeruginosa using three different solvents, namely trifluorocetic acid (TFA; 0.5M), trichloroacetic acid (TCA; 6 per cent w/v) and formic acid (1.0M) Extracts were assayed for uridine 5'-triphosphate (ATP), and guanosine 5'-triphosphate (GTP) by using anion exchange radial compression high performance (pressure) liquid chromatography. The three extraction produres were compared for yield of triphosphates. E. coli, the TFA extraction procedure was more sensitive and reliable than TCA and formic acid extraction procedures, but , in P. aeruginosa, the best yields of ATP and GTP were obrained following extraction with TFA. Yields of UTP and CTP increased when extraction was performed in TCA. These data illustrate that different extraction produres produce different measures for different triphosphates, a point often overlooked.
Date: August 1986
Creator: Dutta, Probir Kumar
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Characterization of the Pigment-Protein and Pigment-ester of Xanthomonas Campestris Pv. Juglandis (open access)

Characterization of the Pigment-Protein and Pigment-ester of Xanthomonas Campestris Pv. Juglandis

The objectives of this project were to develop a high performance liquid chromatographic method for separating the pigment esters mixture, to determine the locations of the pigment moiety in the isolated esters using pholosiphases, and to characterize the pigment-protein complex and determine its distribution in other bacteria. Saponification of the two pigment esters 1 and 2 with aqueous KOH yielded two free pigments on TLC plates developed by two solvent systems. The fasters moving of these two free pigments co-chromatographed with the one free pigment produced from each pigment ester by phospholipase A2 treatment. This suggests that the pigment molecule is a methoxy derivative of xanthomonadin and is esterified to the 2-position of the glycerol moiety of each pigment ester. No free pigment was released from phospholipases C and D treatment of the two pigment esters, indicating that pigment is not esterified to the sorbitol or phosphate moiety of pigment esters 1 or 2.
Date: May 1987
Creator: Lawani, Leonard Olu
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Physiological Responses of Myriophyllum spicatum to Time Varying Exposures of Diquat, 2,4-D and Copper (open access)

Physiological Responses of Myriophyllum spicatum to Time Varying Exposures of Diquat, 2,4-D and Copper

The physiological responses of Myriophyllum spicatum to 2,4-D, diquat and copper were quantified using a plant tissue viability assay, and daily measures of dissolved oxygen and pH. Correlations of herbicide tissue residues to physiological response measures were determined and the relationship was used to develop exposure-response models. Diquat and copper had a greater effect on plant tissue viability than was observed for 2,4-D. Diquat produced greater reductions in dissolved oxygen concentrations and pH values than 2,4-D or copper. Copper exposure had the least effect on these parameters. Exposure-response models developed for 2,4-D predicted effective control at plant tissue residues ranging from 4000 to 4700 mg/kg. Aqueous exposure concentrations necessary to produce effective control plant tissue residues ranged from 0.20 to 0.40 mg/L. Exposure-response models developed for diquat predicted effective control at plant tissue residues ranging from 225 to 280 mg/kg. Aqueous exposure concentrations necessary to produce effective control plant tissue residues ranged from 0.113 to 0.169 mg/L. Exposure-response models developed for copper predicted effective control at plant tissue residues ranging from 680 to 790 mg/kg. Aqueous exposure concentrations necessary to produce effective control plant tissue residues ranged from 0.32 to 0.64 mg/L. Model predictions for 2,4-D, diquat and copper were …
Date: May 1988
Creator: Rocchio, Patricia Mary
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Quantitation of Endogenous Nucleotide Pools in Pseudomonas aeruginosa (open access)

Quantitation of Endogenous Nucleotide Pools in Pseudomonas aeruginosa

Nucleotide pools were extracted and quantified from Pyr^+ and Pyr^- strains of P. aerucjinosa. Strains were grown in succinate minimal medium with and without pyrimidines, and nucleotides were extracted using trichloracetic acid (TCA; 6% w/v). The pyrimidine requirement was satisfied by uracil, uridine, cytosine or cytidine. Pyr^- mutants were starved for pyrimidines for two hours before nucleotide levels were measured. This starvation depleted the nucleotide pools which were restored to wild type levels by the addition of pyrimidines to the medium. When the pyrimidine analogue, 6-azauracil, known to inhibit OMP decarboxylase, was added to cultures of the wild type strain, the uridine and cytidine nucleotides were depleted to near zero. Thus, the nucleotide pool levels of Pseudomonas strains can be manipulated.
Date: August 1988
Creator: Entezampour, Mohammad
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Degradation of Phenolic Acids by Azotobacter Species Isolated from Sorghum Fields (open access)

Degradation of Phenolic Acids by Azotobacter Species Isolated from Sorghum Fields

Sorghum plants excrete phenolic acids which reduce subsequent crop yields. These acids accumulate in field soil by combining with soil and clay particles to form stable complexes which remain until degraded by bacterial metabolism. The amount of phenolic acids in soil samples were obtained by gas chromatography measurements, while Azotobacter populations were obtained by plate counts in 40 sorghum field samples from Denton County, Texas. One can conclude that increasing the Azotobacter population in the soil increased the degradation rate of phenolic acids proportionally. It is proposed that seed inoculation will introduce selected strains of Azotobacter into the soil. The presence of Azotobacter should increase crop size in subsequent plantings.
Date: August 1989
Creator: Al-Hadhrami, Mohamed N. (Mohamed Nasser)
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Effects of Water Quality, Instream Toxicity, and Habitat Variability on Fish Assemblages in the Trinity River, Texas (open access)

Effects of Water Quality, Instream Toxicity, and Habitat Variability on Fish Assemblages in the Trinity River, Texas

The Trinity River flows through the Dallas-Ft. Worth Metroplex in north central Texas where it receives effluents from numerous point sources including seven large regional wastewater treatment facilities. Historically, the Trinity River has been impacted by massive wastewater loadings which often constitute > 80% of the total river discharge during low flow periods. Normally, high mass loadings correspond to the summer months, compounding the effects of a naturally stressful period, characterized by high temperatures and low dissolved oxygen concentrations. Samples from 12 stations were collected quarterly over an 18 month period from the Trinity River and two tributaries. Water samples were analyzed for a variety of water quality variables, including metals, priority pollutants, pesticides, and general water quality parameters. Water samples were also tested for acute and subchronic effects with several test species. Fish were collected at each station and assemblages were characterized using traditional classification techniques and the Index of Biotic Integrity. In addition, sediment samples were assessed for toxic effects which could have adversely impacted fish recruitment and in situ biomonitoring experiments were performed. Quantitative habitat characterization analyses were performed to gain additional information that could possibly explains differences in fish assemblage structure related to habitat variability. Data …
Date: December 1989
Creator: Arnold, Winfred R., 1960-
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Systematics of Coccidian Parasites (Apicomplexa) from Amphibians and Reptiles in Northcentral Texas (open access)

Systematics of Coccidian Parasites (Apicomplexa) from Amphibians and Reptiles in Northcentral Texas

Between February 1986 and October 1988, 863 amphibians and reptiles were collected in northcentral Texas and examined for coccidial parasites. Thirteen percent of amphibians <26% salamanders, 11% frogs and toads) and 28% of reptiles (54% turtles, 25% snakes) harbored 20 previously described and 16 new species of coccidia; overall prevalence of infection was 176/863 < 20%). Sixteen Ambvstoma texanum were infected with Eimeria ambystomae which represents new host and geographic locality records for the coccidium. Forty anurans were found to be passing coccidia, including Pseudacris streckeri. Bufo valliceos and Gastrophryne olivacea. Four new species of coccidia were described from anurans and include Eimeria flexuosa. E. streckeri. Isospora dellcatus and I_. fraaosum. However, oocysts found in B. v.. valliceps were determined experimentally to represent pseudoparasites. Sixty-eight turtles were infected with coccidia, including Chelvdra serpentina, Kinoeternon flavescens. Pseudemvs texana. Terrapeng ornata and Trachemvs scripta eleoans. Fourteen eimerians (5 of which are described as new species) were found in turtles. The new species from turtles include Eimeria cooteri, E. ornata, E. Btvlosa. E. texana and E. trachemvdis. Interestingly, all 96 lizards examined were negative for coccidia. Fifty-three snakes including 11 colubrids and 1 viperld harbored coccidia of the genera Caryospora. Cryptosporidium. Eimeria and …
Date: December 1989
Creator: McAllister, Chris Thomas
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Toxicological Characterization of Trinity River Sediments (open access)

Toxicological Characterization of Trinity River Sediments

Sediments in the Trinity River were chemically, physically and biologically characterized and assessed for toxicity. Laboratory bioassays were conducted to identify sediments which induced toxic responses in test organisms and to document these responses through time. Metal and organic contaminant concentrations in bottom sediments were measured. Relationships between these concentrations and biological responses observed in laboratory bioassays were determined. Toxicity identification / reduction methods were used to characterize sediment toxicants. Sediment oxygen demand was also measured in resuspended and undisturbed bottom sediments through time. The Background Sediment Chemistry Approach and the Sediment Bioassay Approach were used to assess sediment quality. Sediment toxicity was observed in whole sediment bioassays using Chironomus tentans as the test species. A relationship between sediment contaminant concentration and toxicity was observed in approximately sixty percent of the sediments. Oxygen demand of resuspended sediments was elevated in sediments at two locations on the river. Oxygen demand of undisturbed sediments was elevated at one location on the river. Characterization of sediment toxicants was conducted using EDTA, pH, and carbon treatments and manipulations of the sediments. Aeration tests were also used to evaluate the contribution of volatile organic contaminants to observed toxicity.
Date: December 1989
Creator: Hall, Jerry F. (Jerry Fowler)
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Regulation of Colony-Stimulating Factor-1 Biosynthesis (open access)

Regulation of Colony-Stimulating Factor-1 Biosynthesis

Recent studies suggest that synthesis of the Colony-stimulating factor (CSF) is a well regulated process. However, the molecular mechanisms of the signal transduction of the various inducers of CSF such as monokines and lymphokines are not well understood. Using Interleukin 1 (IL-1) stimulation of CSF-1 in the MIA PaCa-2 cell line as a model system, the involvement of G-protein has been studied. The IL-1 induction of CSF-1 synthesis can be inhibited by both Pertussis toxin and Cholera toxin, which are known to modify the Gᵢ and Gₛ proteins respectively, thus activating adenylate cyclase to release more cAMP. The toxin inactivation can be prevented by inhibitors of the ADP-ribosylation such as, benzamide and MBAMG. Addition of dibutyryl-cAMP inhibits the IL-1 induced CSF production. Both Theophylline and Forskolin which increase cAMP by inhibiting phosphodiesterase and stimulating adenylate cyclase respectively, also inhibit CSF-1 production. Results from these studies have shown that cAMP level inversely regulates the biosynthesis of CSF-1. Preincubation of MIA PaCa-2 cells with IL-1 and 5'- guanylylimidodiphosphate (GppNHp) prevents the inhibitory effect of pertussis toxin on CSF-1 production. These data are consistent with the hypothesis that IL-1 binds to its receptor and couples to Gᵢ∝ resulting in the inhibition of adenylate …
Date: May 1990
Creator: Ku, Chun-Ying
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Responses of Pristina leidyi Smith 1896 (Naididae: Oligochaeta) to Cadmium, Vanadium, and Some Environmental Factors (open access)

Responses of Pristina leidyi Smith 1896 (Naididae: Oligochaeta) to Cadmium, Vanadium, and Some Environmental Factors

Concern over sediment toxicity has increased the need for toxicity test information with organisms that inhabit sediments. Oligochaetes are exposed to toxicants through feeding and direct body contact with aquatic sediments. Chronic testing with oligochaetes has historically focused on tubificids with test lengths of one year or more to encompass several generations. Most naidid oligochaetes have generation times of three to seven days and could provide chronic information in a matter of weeks. The cosmopolitan distributed naidid, Pristina leidyi, was evaluated for use as a toxicity test organism. Results of research conducted includes culture methods, effects of temperature on reproduction, growth rates in a reference sediment, acute toxicity tests, and chronic toxicity tests.
Date: May 1990
Creator: Smith, David P. (David Paul), 1956-
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Effects of Long Term Modernate Ethanol Intake on Plasma Levels of ACTH, Beta Endorphin, and Corticosterone in Rats (open access)

The Effects of Long Term Modernate Ethanol Intake on Plasma Levels of ACTH, Beta Endorphin, and Corticosterone in Rats

The effects of single injections and daily oral administration of ethanol on plasma levels of ACTH, beta endorphin, and corticosterone in response to cold stress were examined. The long-term experimental animals were given 0.25 ml of 28% ethanol or water orally once a day, five days a week, for fourteen months. Plasma levels of ACTH, beta endorphin, and corticosterone were lower in alcohol-treated rats as compared with water-treated rats when exposed to cold stress. The effects of a single injection of ethanol significantly elevated plasma levels of all three hormones. Mortality in sham-treated males was higher than ethanol-treated.
Date: December 1990
Creator: Breedlove, Kenneth
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Comparative Toxicity of Refuse-Derived Fuel Fly Ash on Two Species of Earthworms, Lumbricus terrestris and E. foetida, Using an Artificial Soil Exposure Protocol (open access)

Comparative Toxicity of Refuse-Derived Fuel Fly Ash on Two Species of Earthworms, Lumbricus terrestris and E. foetida, Using an Artificial Soil Exposure Protocol

Research estimated toxicity of refuse-derived fuel fly ash (RDF-FA) on two earthworms species, Lumbricus terrestris and Eisenia foetida. Specific objectives were to: (1) Compare their 14-day LC50s under light and dark conditions; (2) separate toxicity due to osmotic, pH and physical factors from that of heavy metal contaminants; (3) compare relative differences of artificial soil and commercial soil as exposure media for evaluating toxicity to earthworms. The 14-d LC50s for L. terrestris in dark and light were 57.0 and 48.34 % RDF-FA, and 59.25 and 41.00 % RDF-FA for E. foetida using artificial soil. All of the toxicity resulted from heavy metals within the RDF-FA. Using L. terrestris, the LC50s for artificial soil and commercial soil were 52.30 and 64.34%.
Date: May 1991
Creator: Jahani, Aghamolla
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Characterization of Pyrimidine Biosynthesis in Pseudomonas putida Using Mutant and Wild Type Strains (open access)

Characterization of Pyrimidine Biosynthesis in Pseudomonas putida Using Mutant and Wild Type Strains

The biosynthesis of pyrimidines in Pseudomonas putida was investigated. In this study, pyrimidine requiring mutants were isolated by conventional mutagenesis and enrichment. The strains required exogenously supplied pyrimidines for growth and were found by enzyme assays to be deficient for the product of the pyrB gene encoding the enzyme aspartate transcarbamoylase. None of the intermediates of the pathway could supply the auxotrophic requirement of the strain; only preformed pyrimidines, metabolized via salvage pathways could suffice. Pyrimidine limitation in the mutant caused a slight but significant fifty per cent increase in expression of all the de novo biosynthetic enzymes. Pyrimidine starvation's effect on nucleotide pool levels was examined in the mutant and caused a marked swelling of the purine nucleotide pools.
Date: August 1991
Creator: Chang, Mingren
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Effects of Trichinella Soluble Antigens on Macrophage Subpopulations (open access)

Effects of Trichinella Soluble Antigens on Macrophage Subpopulations

The immunomodulatory effects of Trichinella spiralis or Trichinella pseudospiralis soluble antigen extracts were examined in an effort to characterize the differences in immune responses seen during these Trichinella infections. The newborn larvae extracts of either parasite exhibited similar potency for stimulating macrophage PGE production; however, the muscle larvae extracts of T. pseudospiralis stimulated greater levels of PGE than did the muscle larvae extracts of T. spiralis. These data clearly indicate that Trichinella antigens possess immunomodulatory capabilities.
Date: August 1992
Creator: Dixon, Guy Cameron, 1960-
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Cardiorespiratory Responses to Graded Levels of Lower-body Positive Pressure During Dynamic Exercise in Man (open access)

Cardiorespiratory Responses to Graded Levels of Lower-body Positive Pressure During Dynamic Exercise in Man

Cardiorespiratory responses to incremental dynamic exercise were assessed across four different levels of lower-body positive pressure (LBPP) and, as a separate study, during constant load (i.e constant work rate) exercise below and above each subject's ventilatory threshold (VT), both with and without 45 torr of LBPP.
Date: December 1992
Creator: Williamson, Jon W. (Jon Whitney)
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Evaluation of Diet, Water, and Culture Size for Ceriodaphnia Dubia Laboratory Culturing (open access)

Evaluation of Diet, Water, and Culture Size for Ceriodaphnia Dubia Laboratory Culturing

Six reagent waters, eleven diets, and two culture sizes were evaluated for culturing C. dubia. Different filtration techniques were used to prepare the reagent waters. The eleven diets were comprised of two algae augmented with eight supplements. Reproduction and growth were assessed to discern differences among C. dubia raised in mass cultures and cultured in individual cups, during which, bacterial population densities, lipid, protein, and carbohydrate concentrations of the diets were measured. Results showed that a glass-distilled, carbon filtered, deionized reagent water and a Selenastrum capricornutum- Cerophyl® diet were optimum for culturing. Mass culturing supported the highest reproduction and growth, while no correlation was found between nutritional measurements and production.
Date: December 1992
Creator: Allen, Jerry D. (Jerry Dee)
Object Type: Thesis or Dissertation
System: The UNT Digital Library
An Interpretation of Archaic Medical Treatises (open access)

An Interpretation of Archaic Medical Treatises

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 through generations of preliterate peoples. The context for mythological memorization, or simply tradition, needed to be easily and naturally acquired. The ideal context was the anthropomorphic context, the ontogenic context. This is the Grand Allegory - the anthropomorphization of information. Biomyths are essentially biological texts allegorized in esoteric language.
Date: May 1993
Creator: Wagers, William D. (William Delbert)
Object Type: Thesis or Dissertation
System: The UNT Digital Library