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 Department: Department of Biological Sciences
 Degree Discipline: Biology
 Collection: UNT Theses and Dissertations
Classification of toolmark surfaces on zipper teeth

Classification of toolmark surfaces on zipper teeth

Date: December 1999
Creator: Jacobsen, Dawn
Description: This study proposes the classification of the toolmark under the heads of zipper teeth as a subclass characteristic as outlined by the Association of Firearm and Toolmark Examiners (AFTE). Two separate cases in which zipper teeth were found at crime scenes prompted this study. Brass zipper teeth manufactured by YKK were taken from 20 pairs of jeans and studied using a Reichert comparison microscope at 4X power. Photographs were taken and over 750 comparisons made. It was found that the toolmarks on each side on the 20 zippers were unique and independent of all other sides. The observations made in this study indicate that classifying zipper teeth toolmarks as a subclass characteristic is valid.
Contributing Partner: UNT Libraries
Clustering Algorithms for Time Series Gene Expression in Microarray Data

Clustering Algorithms for Time Series Gene Expression in Microarray Data

Date: August 2012
Creator: Zhang, Guilin
Description: Clustering techniques are important for gene expression data analysis. However, efficient computational algorithms for clustering time-series data are still lacking. This work documents two improvements on an existing profile-based greedy algorithm for short time-series data; the first one is implementation of a scaling method on the pre-processing of the raw data to handle some extreme cases; the second improvement is modifying the strategy to generate better clusters. Simulation data and real microarray data were used to evaluate these improvements; this approach could efficiently generate more accurate clusters. A new feature-based algorithm was also developed in which steady state value; overshoot, rise time, settling time and peak time are generated by the 2nd order control system for the clustering purpose. This feature-based approach is much faster and more accurate than the existing profile-based algorithm for long time-series data.
Contributing Partner: UNT Libraries
Coelomic fluid protein profile in earthworms (Lumbricus terrestris) following bacterial challenge.

Coelomic fluid protein profile in earthworms (Lumbricus terrestris) following bacterial challenge.

Date: December 2006
Creator: Brooks, Geoffrey Lance
Description: Proteomic techniques were used to evaluate the protein profile of the earthworm, (Lumbricus terrestris), following a bacterial challenge. One control group received no injection; a second control group received injections of phosphate buffer solution (PBS). The experimental group received injections of PBS containing (Aeromonas hydrophila). After incubation for 12 hours at 20°C, coelomic fluid was collected from each group for analysis by 2-D electrophoresis. There were significant differences in spot appearance and density between control and experimental groups. Sixteen spots showed a two-fold increase in density and 63 showed at least a two-fold decrease in density between samples from control and bacteria-challenged earthworms, respectively, suggesting up- and down-modulation of proteins potentially involved in the earthworm's response to bacterial challenge.
Contributing Partner: UNT Libraries
College Freshman Biology Two Semester Course: Integrating Deep Processing Teaching Techniques

College Freshman Biology Two Semester Course: Integrating Deep Processing Teaching Techniques

Date: May 2002
Creator: Blevins, Mary Jean
Description: Development of a college level freshman biology course was undertaken in response to government reports that American students have fallen behind students of other countries in the area of the sciences. Teaching strategies were investigated to accomplish two objectives, to define essential academic material to include in the course and to investigate teaching techniques that would increase deep processing of the information. An active process that consisted of applying the cognitive information to solving problems or developing answers to questions was defined as critical thinking. Critical thinking was incorporated into the course by the use of case studies.
Contributing Partner: UNT Libraries
Comparative biochemistry and genetic analysis of nucleoside hydrolase in  Escherichia coli,  Pseudomonas aeruginosa, and  Pseudomonas fluorescens.

Comparative biochemistry and genetic analysis of nucleoside hydrolase in Escherichia coli, Pseudomonas aeruginosa, and Pseudomonas fluorescens.

Date: December 2002
Creator: Fields, Christopher J.
Description: The pyrimidine salvage enzyme, nucleoside hydrolase, is catalyzes the irreversible hydrolysis of nucleosides into the free nucleic acid base and D-ribose. Nucleoside hydrolases have varying degrees of specificity towards purine and pyrimidine nucleosides. In E. coli, three genes were found that encode homologues of several known nucleoside hydrolases in protozoa. All three genes (designated yaaF, yeiK, and ybeK) were amplified by PCR and cloned. Two of the gene products (yeiK and ybeK) encode pyrimidine-specific nucleoside hydrolases, while the third (yaaF) encodes a nonspecific nucleoside hydrolase. All three were expressed at low levels and had different modes of regulation. As a comparative analysis, the homologous genes of Pseudomonas aeruginosa and P. fluorescens (designated nuh) were cloned. Both were determined to encode nonspecific nucleoside hydrolases. The nucleoside hydrolases of the pseudomonads exhibited markedly different modes of regulation. Both have unique promoter structures and genetic organization. Furthermore, both pseudomonad nucleoside hydrolase were found to contain an N-terminal extension of 30-35 amino acids that is shown to act as a periplasmic-signaling sequence. These are the first two nucleoside hydrolases, to date,that have been conclusively demonstrated to be exported to the periplasmic space. The physiological relevance of this is explained.
Contributing Partner: UNT Libraries
Comparative morphology of sensilla styloconica on the proboscis of North American Nymphalidae and other selected taxa (Lepidoptera): systematic and ecological considerations.

Comparative morphology of sensilla styloconica on the proboscis of North American Nymphalidae and other selected taxa (Lepidoptera): systematic and ecological considerations.

Access: Use of this item is restricted to the UNT Community.
Date: December 2001
Creator: Petr, Daniel
Description: Sensilla styloconica on the proboscis of 107 species of North American and tropical butterflies were comparatively studied using the scanning electron microscope. Focus was on 76 species of North American Nymphalidae representing 45 genera and 11 subfamilies. Nomenclature for generalized and specific types of nymphalid sensilla is proposed. Written descriptions and micrographs are presented for each species studied. Morphological features were generally consistent for all or most species within genera and sometimes within subfamilies, with specified exceptions. Statistical analysis revealed significant differences for six of eight variables tested between two distinct feeding guilds of North American Nymphalidae. Average number, density, extent of proboscis coverage with sensilla, their total length, and shoulder spine length were all significantly greater in the non-nectar feeding guild than in nectar feeders, and may indicate adaptation for greater efficiency in feeding on flat surfaces. The greater frequency of apical shoulder spines in non-nectar feeders may represent adaptation for protection of sensory pegs from mechanical abrasion during feeding, or for anchoring the flexible proboscis tip to the surface. Correlation analysis revealed 9 out of 28 positive correlations in nectar feeders and 5 out of 28 in non-nectar feeders. Results of preliminary cladistic analysis were not considered to ...
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A Comparative Study of Passive Transfer Mechanisms of Tuberculin and Chemical Contact Delayed Hypersensitivities in the Guiea Pig

A Comparative Study of Passive Transfer Mechanisms of Tuberculin and Chemical Contact Delayed Hypersensitivities in the Guiea Pig

Date: June 1970
Creator: Nunez, William Joseph
Description: This study is concerned with a critical comparison of the passive transfer mechanisms of tuberculin and chemical contact hypersensitivities in the guinea pig by use of a four phase experimental approach.
Contributing Partner: UNT Libraries
Comparison of Heteranthera Dubia (Jacq.) MacM.-associated Macroinvertebrates Between Georgraphical Regions in the United States

Comparison of Heteranthera Dubia (Jacq.) MacM.-associated Macroinvertebrates Between Georgraphical Regions in the United States

Date: May 2010
Creator: Harms, Nathan Earl
Description: Macroinvertebrates associated with the aquatic plant, water stargrass (Heteranthera dubia), were sampled from 12 waterbodies in four regions of the United States from June to August 2005. Taxa richness, evenness, and diversity were lowest in the Lower Midwest (LMW) region, and higher in Northern sites, especially the Upper Midwest (UMW), and Northeast (NE). While relative abundance varied from site to site and region to region, utilization of the plant by functional groups remained fairly constant. Collector-gatherers consistently comprised the largest portion of invertebrates sampled. The shredder/ herbivore functional group comprised an average of 17 % of total groups. Through an exhaustive literature review, it was found that shredder/ herbivores of water stargrass have not been reported in the literature. Because of this, the herbivore group was analyzed separately and consisted of 2,383 specimens representing 23 species. The most common groups were Rhopalosiphum sp., Nectopsyche spp. and chironomids. No differences were found in herbivore diversity or evenness between sampling regions, but species richness was significantly different.
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Comparison of Remediation Methods in Different Hydrogeologic Settings Using Bioplume II

Comparison of Remediation Methods in Different Hydrogeologic Settings Using Bioplume II

Date: May 1996
Creator: White, Sherry A. (Sherry Anne)
Description: A contaminant fate and transport computer model, Bioplume II, which allows simulation of bioremediation in ground water systems, was used to compare the effects of 11 remediation scenarios on a benzene plume. The plume was created in three different hydrogeologic settings from the simulation of an underground gasoline storage tank leak.
Contributing Partner: UNT Libraries
Concentration-dependent Effects of D-Methylphenidate on Frontal Cortex and Spinal Cord Networks in vitro

Concentration-dependent Effects of D-Methylphenidate on Frontal Cortex and Spinal Cord Networks in vitro

Date: December 2004
Creator: Miller, Benjamin R.
Description: Spontaneously active frontal cortex and spinal cord networks grown on microelectrode arrays were used to study effects of D-methylphenidate. These central nervous system tissues have relatively low concentrations of dopaminergic and noradrenergic neurons compared to the richly populated loci, yet exhibit similar neurophysiological responses to methylphenidate. The spontaneous spike activity of both tissues was inhibited in a concentration-dependent manner by serial additions of 1-500 µM methylphenidate. Methylphenidate is non-toxic as spike inhibition was recovered following washes. The average concentrations for 50% spike rate inhibition (IC50 ± SD) were 118 ± 52 (n= 6) and 57 ± 43 (n = 11) for frontal cortex and spinal cord networks, respectively. A 3 hour exposure of a network to 1 mM methylphenidate was nontoxic. The effective concentrations described in this study are within the therapeutic dosage range. Therefore, the platform may be used for further investigations of drug mechanisms.
Contributing Partner: UNT Libraries