Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

Theses and Dissertations

Discipline
Institution
Keyword
Publication Year
File Type

Articles 4261 - 4290 of 5010

Full-Text Articles in Life Sciences

An Acyl Radical Cascade Model For The Total Synthesis Of Lyconadin A, Seth W. Grant Sep 2005

An Acyl Radical Cascade Model For The Total Synthesis Of Lyconadin A, Seth W. Grant

Theses and Dissertations

Lyconadin A (1) is a structurally unique Lycopodium alkaloid with antitumor properties, isolated from the club moss Lycopodium complanatum. We are developing a synthetic route to 1 based on a novel 7-exo-trig/6-exo-trig acyl radical cascade cyclization. The synthesis of model acyl radical cascade precursor 23 will be presented. Key features of this synthesis include the suppression of competing elimination during the alkylation of a hindered phenethyl bromide and the use of a lactone as a precursor to a compound bearing two differentially protected primary alcohols. An account of our studies on the model acyl radical cascade cyclization (23 to 24 …


Effect Of Melatonin And Dopamine In Site Specific Phosphorylation Of Phosducin In Intact Retina, Arinzechukwu Okere Nkemdirim Aug 2005

Effect Of Melatonin And Dopamine In Site Specific Phosphorylation Of Phosducin In Intact Retina, Arinzechukwu Okere Nkemdirim

Theses and Dissertations

Phosducin (Pdc) is a 28 kDa binding partner for the G protein beta gamma subunit dimer (G-beta-gamma) found abundantly in the photoreceptor cells of the retina and pineal gland. In the retina, light-dependent changes in cAMP and Ca2+ control the phosphorylation of Pdc at serine 73 and 54, respectively, which in turn controls the binding of Pdc to G protein beta gamma subunit dimer . G protein beta gamma subunit dimer binding has been proposed to facilitate light-driven transport of G protein beta gamma subunit dimer from the site of phototransduction in the outer segment of the photoreceptor cell to …


The Effect Of Leisure-Based Screen Time On Physical Activity, Mary Dawn Sperry Jul 2005

The Effect Of Leisure-Based Screen Time On Physical Activity, Mary Dawn Sperry

Theses and Dissertations

The purpose of this study was to determine the effect of leisure-based screen time on physical activity. Ninety-four families participated in this six-week study. Each family was randomly assigned to one of three screen time groups: (1) control group (2) 2-hour-limit group or (3) one-hour-limit group. Family members wore a Walk4Life LS 2505® pedometer to measure steps. Daily screen time logs were filled out each night and leisure-based screen time and steps were recorded. Analysis of variance (steps x group) was used to determine differences among the groups. Univariate tests showed there were no significant differences among any of the …


Reaction Of Tardigrades (Hypsibius) To Physical And Chemical Extremes, Limor Raz Jul 2005

Reaction Of Tardigrades (Hypsibius) To Physical And Chemical Extremes, Limor Raz

Theses and Dissertations

The process of cryptobiosis is characterized by a complete state of body water dehydration and undetectable metabolic activity, which allows tardigrades {Hypsibius) to escape environmental stress when conditions become unfavorable. In our research, Hypsibius was tested in a laboratory under pH levels of 3 to 10 and a salinity concentration gradient. In the pH experiment, we placed tardigrades in petri dishes with agar solution in an experimental pH and measured the average distance traveled. We expected them to respond favorably to a neutral pH of 7 which is common in most living organisms by showing increased movement. In the salinity …


The Perceptions Of High School Physical Educators On The Benefits Of Block Scheduling In The State Of Utah, Marilyn Miller Jul 2005

The Perceptions Of High School Physical Educators On The Benefits Of Block Scheduling In The State Of Utah, Marilyn Miller

Theses and Dissertations

The purpose of this research was to examine the extent to which the block schedule is being used in Utah high school physical education, and determine teacher's perceptions of block scheduling in teaching physical education. Block scheduling is a new and more efficient way of organizing the school day. NASPE has found the following positive effects in block scheduling: a better learning environment, more access to stronger curriculum, detailed instruction and demonstrations, and more variety in assessment (NASPE, 2000). Although there were several different forms of the block schedule reported, it appears that a majority of physical educators have discovered …


Development Of A Model For The Kinetics And Mechanism Of Nitrogenase, Phillip E. Wilson Jul 2005

Development Of A Model For The Kinetics And Mechanism Of Nitrogenase, Phillip E. Wilson

Theses and Dissertations

Nitrogenase has a central role in the global nitrogen cycle as the enzyme that catalyzes the reduction of atmospheric N2 to NH3. Fixed nitrogen is generally limiting in the environment and in agriculture, so nitrogenase has received much attention as an alternative to nitrogen fertilizers. Characterizing the mechanism of nitrogenase is the goal of this work. The molybdenum nitrogenase enzyme system is comprised of the MoFe protein and the Fe protein. Interactions between these proteins and nucleotides are crucial to catalysis. An important approach to characterize these interactions is to correlate the kinetics of nitrogenase catalysis to a mechanism based …


Angiotensin Ii-Mediated Regulation Of The Human Angiotensin Ii Type 1 Receptor Gene, Xylophone Vijai Aasee Victor Jul 2005

Angiotensin Ii-Mediated Regulation Of The Human Angiotensin Ii Type 1 Receptor Gene, Xylophone Vijai Aasee Victor

Theses and Dissertations

The physiological responses of angiotensin II (Ang II) are mediated across the cell membrane through the angiotensin II type 1 receptor (AT1R), a heptahelical membrane protein coupled to trimeric G-proteins on the cytosolic side. AT1R on binding its ligand, Ang II, leads to downregulation of cell-surface receptor and also its mRNA. We have investigated whether the 3'- and 5'-untranslated regions of the human AT1R mRNA mediate the degradation of hAT1R mRNA by post-transcriptional mechanisms in human adrenocortical carcinoma cell line (H295R cells). Protein kinase C (PKC) activator, phorbol-12-myristate-13-acetate (PMA), showed that the downregulation of hAT1R mRNA is mediated by the …


Homologous Strand Exchange And Dna Helicase Activities In Plant Mitochondria, Daqing Song Jul 2005

Homologous Strand Exchange And Dna Helicase Activities In Plant Mitochondria, Daqing Song

Theses and Dissertations

Homologous recombination is critical for generating genetic variation in living organisms by exchange and rearrangement of DNA. Most of our knowledge about homologous recombination is limited to processes in bacteria or in eukaryotic nuclei. In E. coli, homologous recombination is dependent on the RecA protein. Higher plant chloroplasts have RecA-like strand exchange activity. However, little is known about these mechanisms in higher plant mitochondria. I have detected a RecA-like strand exchange activity in soybean mitochondria. This activity forms joint molecules in the presence of ATP, Mg2+, and homologous DNA substrates. In addition, the E. coli single-stranded DNA binding (SSB) protein …


Genetic Analysis Of Conserved Residues In Phou Of Escherichia Coli, Stewart G. Gardner Jul 2005

Genetic Analysis Of Conserved Residues In Phou Of Escherichia Coli, Stewart G. Gardner

Theses and Dissertations

The Pho regulon is controlled by the PstSCAB transporter, PhoU, and the two-component proteins, PhoB and PhoR. PhoU is a negative regulator of the Pho regulon under phosphate-replete conditions. How PhoU functions is unknown. Many PhoU homologues are found widely throughout prokaryotic domains. There are several conserved amino acid residues in the PhoU protein. It is hypothesized that these residues play an important role in the function of PhoU. To test this hypothesis, several site directed mutations in the phoU gene have been produced with single amino acid changes in conserved residues. After testing these mutants, it was found that …


Time Efficiency In Computer Assisted Direct Observation Of Physical Activity Using Sofit, Trisha Anderson Jul 2005

Time Efficiency In Computer Assisted Direct Observation Of Physical Activity Using Sofit, Trisha Anderson

Theses and Dissertations

Having valid and reliable methods for assessing physical activity levels is critical to understanding physical activity patterns. Direct observation is a widely used technique for obtaining contextually rich data on physical activity levels in physical education classes. One major limitation of direct observation is that it is time intensive. The use of digital video editing software programs may lessen the amount of time needed to gather the data. The purpose of this study was to compare the amount of time needed to obtain SOFIT (System for Observing Fitness Instruction Time) physical activity data using the traditional paper and pencil method …


The Association Between Changes In Body Fat, Body Weight And Serum C-Reactive Protein: A Prospective Study, Benjamin Thomas Bikman Jul 2005

The Association Between Changes In Body Fat, Body Weight And Serum C-Reactive Protein: A Prospective Study, Benjamin Thomas Bikman

Theses and Dissertations

Objective- To investigate the extent to which changes in body fat percentage (BF%) and weight (BW) relate to changes in C-reactive protein (CRP) in women, while statistically controlling for possible confounders, such as age, initial body weight, and menopause status.

Methods and Results- A cohort of 150 free-living subjects was followed prospectively over a 2½-year period. BF% was measured using dual energy X-ray absorptiometry (DEXA), while BW was determined with a calibrated, electronic scale. There was no significant relationship between changes in BF% and CRP, regardless of age, initial BW, and menopause status. However, changes in BW were predictive of …


Soft Drink Consumption And Changes In Body Composition In 170 Women: A 4-Year Prospective Study, Jared Michael Tucker Jul 2005

Soft Drink Consumption And Changes In Body Composition In 170 Women: A 4-Year Prospective Study, Jared Michael Tucker

Theses and Dissertations

Background: In recent history, there have been significant increases in both soft drink consumption and the prevalence of obesity throughout the developed world. To help curb the obesity epidemic, a better understanding of the behaviors contributing to weight and fat gain is vital.

Objective: To examine the extent to which soft drink consumption is predictive of changes in body composition in middle-aged women over a 4-year period, while statistically controlling for age, energy intake, physical activity, and menopause status.

Design: A prospective cohort design over 48 months with no intervention. Self-reported soft drink consumption was used to predict changes in …


Investigation Of The Mechanisms Of Ozone-Mediated Viral Inactivation, Seiga Ohmine Jul 2005

Investigation Of The Mechanisms Of Ozone-Mediated Viral Inactivation, Seiga Ohmine

Theses and Dissertations

Previous studies have established that ozone-oxygen mixtures can be used to inactivate a variety of microorganisms including bacteria, fungi and viruses. Ozone is a potent reactive oxygen species (ROS) that rapidly decays into a variety of additional short half-life ROS which have been shown to cause oxidative damage to biological molecules. I hypothesize that controlled ozone exposure and the subsequent generation of additional ROS would reduce viral infectivity by lipid and/or protein peroxidation. A proprietary ozone-oxygen delivery system was used to inactivate a series of enveloped [herpes simplex virus type-1 strain McIntyre (HSV-1), vaccinia strain Elstree (VAC), vesicular stomatitis virus …


Microbial And Chemical Affects On Leachate From Calcareous Soils Treated With Wastewater Effluent, Craig M. Paul Jul 2005

Microbial And Chemical Affects On Leachate From Calcareous Soils Treated With Wastewater Effluent, Craig M. Paul

Theses and Dissertations

Increasing human populations are placing greater strain on water resources, prompting the use of treated wastewater effluent for irrigation in some areas, including the desert regions of the Western United States. To determine the potential effects of using secondary effluent for irrigation, we applied wastewater effluent and irrigation waters to natural and artificially constructed calcareous soils in greenhouse and field lysimeters, and in soil columns. The leachate from one field lysimeter contained increased fecal coliform counts than the effluent. Leachate coliform counts were decreased or not significantly changed in two field lysimeters. Electrical conductivity (EC), sodium adsorption ratio (SAR), chloride …


Whole-Body Vibration And Its Effects On Electromechanical Delay And Vertical Jump Performance, Deja Lee Stevenson Jun 2005

Whole-Body Vibration And Its Effects On Electromechanical Delay And Vertical Jump Performance, Deja Lee Stevenson

Theses and Dissertations

The purpose of this study was to determine the effects of whole-body vibration on electromechanical delay and vertical jump performance. Twenty college aged subjects participated in 10 intervals of whole-body vibration (WBV) at a frequency of 26 Hz and amplitude of 5 mm. Each interval consisted of 60 s of WBV in a half-squat followed by 60 s of rest. After 5 intervals, subjects had 6 min of rest before the final 5 intervals. Each subject also participated in the control which included the same 10 intervals in a half-squat without the WBV. Tests were conducted to assess electromechanical delay …


Phylogeny And Biogeography Of Ice Crawlers (Insecta: Grylloblattodea): Evidence From Six Molecular Loci, Karl J. Jarvis Jun 2005

Phylogeny And Biogeography Of Ice Crawlers (Insecta: Grylloblattodea): Evidence From Six Molecular Loci, Karl J. Jarvis

Theses and Dissertations

Ice crawlers (Insecta: Grylloblattodea) are rarely encountered insects that consist of five genera representing 26 species from North America and Asia. Asian grylloblattids are the most diverse, but North American ice crawlers (genus Grylloblatta) are known for their adaptation to cold conditions. Phylogenetic relationships among grylloblattid species and genera are not known. Late Pleistocene glaciations had a major effect on the current Grylloblatta distribution, because their specific habitat requirements restrict them to small geographical areas. Six genes were sampled in 37 individuals for 18S rRNA, 28S rRNA, histone 3, 12S rRNA, 16S rRNA, and cytochrome oxidase II (COII) from 27 …


Crustacean Phylogenetic Systematics And Opsin Evolution, Megan L. Porter Jun 2005

Crustacean Phylogenetic Systematics And Opsin Evolution, Megan L. Porter

Theses and Dissertations

Composed of a chromophore bound to an integral membrane protein (opsin), visual pigments are phenotypically characterized by the wavelength of maximal absorption (λmax). The underlying molecular mechanism controlling λmax is the interaction between the opsin amino acid sequence and the chromophore. While a plethora of studies have looked at structure/function relationships in vertebrate opsins, fewer studies have investigated similar issues in invertebrates. Furthermore, those few studies undertaken in invertebrate systems suggest different mechanisms of spectral tuning and photoactivation compared to vertebrate systems. This dissertation research is focused on expanding our knowledge of opsin evolution in invertebrate systems, particularly from non-insect …


Assessment Of Cell Death Parameters In Bovine Parvovirus-Infected Ebtr Cells, Lubna Salah Eldin Abdel Latif Jun 2005

Assessment Of Cell Death Parameters In Bovine Parvovirus-Infected Ebtr Cells, Lubna Salah Eldin Abdel Latif

Theses and Dissertations

Bovine parvovirus (BPV) is a helper-independent parvovirus. It has a small icosahedral capsid with a single stranded DNA genome. It is a highly stable virus with a narrow host range. It causes acute gastroenteritis in calves. It is considered to be a cytolytic virus because it kills the host cells. However, the mechanism by which the virus causes cell death is not known. The work described in this thesis assessed different parameters of cell death in BPV infected embryonic bovine tracheal (EBTr) cells. There are several ways for viruses to induce cell death. Viruses can induce apoptosis in the infected …


The Effect Of Teaching With Acoustical Guidance (Tag) On The Mastery Of A Grand Rond De Jambe (En Dehors) And A Ballotte, Heidi Dutch Schneider May 2005

The Effect Of Teaching With Acoustical Guidance (Tag) On The Mastery Of A Grand Rond De Jambe (En Dehors) And A Ballotte, Heidi Dutch Schneider

Theses and Dissertations

This study examined the effect of Teaching with Acoustical Guidance (TAG) on the mastery of two ballet skills, the Grand Rond de Jambe (en dehors) and a Ballotte'. Dance technique classes still follow traditional methods of teaching and mastering skills without much integration of motor learning concepts. TAG Teach is a method that uses positive reinforcement, shaping, and a hand held device that produces an acoustic sound to mark correct behaviors at the moment they occur. The purpose of this study was to determine if TAG was a faster and more effective technique to aid in the mastery of two …


Digestibility, Nitrogen Balance, And Blood Metabolites In Llama And Alpaca Fed Barley And Barley Alfalfa Forages., Heather Loree Davies Apr 2005

Digestibility, Nitrogen Balance, And Blood Metabolites In Llama And Alpaca Fed Barley And Barley Alfalfa Forages., Heather Loree Davies

Theses and Dissertations

These projects were conducted to determine the digestibility of forage diets with differing CP levels in llamas and alpacas. The Utah study was designed to compare llama and alpaca nutritional parameters to determine if nutritional recommendations for llamas can be directly extrapolated to alpacas. The first study evaluated the effects of forage quality on blood metabolites and nitrogen balance in mature, intact male llamas (n = 4, 36 ± 4.4 months, 87 ± 17 kg) at high altitude in Letanias, Bolivia (4,267 m = aprox.14,000 ft above sea level). A second experiment was conducted with eight adult gelded camelids (n …


Alterations In Uterine And Placental Sodium Pump Abundance May Contribute To The Onset Of Mouse Labor, Carlos Jacob Vance Mar 2005

Alterations In Uterine And Placental Sodium Pump Abundance May Contribute To The Onset Of Mouse Labor, Carlos Jacob Vance

Theses and Dissertations

Objective: Reductions in sodium pump (SP) abundance can give rise to increases in contractile force in uterine and vascular smooth muscle as well as an increased secretion in secretory cells, including potentially those of the placenta. To determine whether the mouse might serve as a model for human pregnancy in terms of the SP and to determine whether changes in SP abundance anticipate or follow labor, we studied pregnant mice over the final trimester of their pregnancy.

Study Design: C57Bl6 dams (n=46) were bred and studied during their pregnancy. Animals (n=4) were sacrificed at specific gestational time points. Other mice …


Ion Transmission In The First Vacuum Stage Of An Inductively Coupled Plasma Mass Spectrometer, Jeffrey Harris Macedone Mar 2005

Ion Transmission In The First Vacuum Stage Of An Inductively Coupled Plasma Mass Spectrometer, Jeffrey Harris Macedone

Theses and Dissertations

The inductively coupled plasma mass spectrometer (ICP-MS) is the instrument of choice for trace and ultra-trace elemental analysis. However, the ICP-MS suffers from matrix effects. Matrix effects occur when instrument response varies as the composition of the sample matrix is changed. Matrix effects, or non-spectroscopic interferences, limit the accuracy of routine analysis. Identification of the sources of matrix effects provide a basis for reducing or eliminating them. As inaccuracies in the ICP-MS are more severe than those in the ICP atomic emission spectrometer, the problem may be due, at least in part, to the vacuum interface used to couple the …


Phylogenetic Relationship Of Forest Spiny Pocket Mice (Genus Heteromys) Inferred From Mitochondrial And Nuclear Markers With Implications For Species Boundaries, Malinda Wallentine Gonzalez Mar 2005

Phylogenetic Relationship Of Forest Spiny Pocket Mice (Genus Heteromys) Inferred From Mitochondrial And Nuclear Markers With Implications For Species Boundaries, Malinda Wallentine Gonzalez

Theses and Dissertations

I constructed a best estimate phylogeny based on congruence of multiple data sources. In recent years molecular data has been used both to construct phylogenies of taxonomic groups and to aid in the delimitation of new species. I generated and analyzed sequence data for forest spiny pocket mice (Genus Heteromys) for the mitochondrial gene cyt b (1143 bp) and two nuclear gene segments MYH2 (252 bp) and EN2 (189 bp). I used maximum parsimony and Bayesian analyses to infer relationships among species and to provide a framework for using a species delimitation method to investigate the possibility of multiple …


The Difference In Hr Response Between Track And Treadmill Running At A Pre-Determined, Self-Selected Pace, Marisha Corey Mar 2005

The Difference In Hr Response Between Track And Treadmill Running At A Pre-Determined, Self-Selected Pace, Marisha Corey

Theses and Dissertations

The purpose of this study was to determine whether or not differences exist in heart rate (HR) between jogging on the track and jogging on the treadmill at the same speed. Twenty-four college-age (19-31 years old) male (n = 12) and female (n = 12) recreational runners volunteered to participate in this study. Each participant performed a maximal graded exercise test (GXT) and four exercise sessions. During the first exercise session, participants completed a 1-mile steady-state jog on either the track or treadmill at a self-selected submaximal pace that could be maintained for 30 minutes. The following three exercise sessions …


Differences In Maximal Speed Running Between Baseball Players And Sprinters, Erin Kathleen Robinson Mar 2005

Differences In Maximal Speed Running Between Baseball Players And Sprinters, Erin Kathleen Robinson

Theses and Dissertations

The purpose of this study was to examine the differences in technique between sprinters and baseball players while running at maximal speeds. 20 male NCAA Division I athletes participated; ten members of the track and field team specializing in the 100 m or 200 m sprint or the 100 m hurdles and ten members of the baseball team. Each subject performed a maximal effort 80 m sprint while their sprint times were recorded every 10 m starting at the 20 m mark. Each subject was filmed at they ran through a set10 m marking that included where they reached their …


Effects Of Same-Day Strength Training On Serve Performance In Female Collegiate Tennis Players, Staci Kayleen Reynolds Mar 2005

Effects Of Same-Day Strength Training On Serve Performance In Female Collegiate Tennis Players, Staci Kayleen Reynolds

Theses and Dissertations

The purpose of this study was to evaluate the effects of same-day strength training on velocity and accuracy of a tennis serve among five female Division I intercollegiate athletes at the second and sixth week of a strength training program. Velocity and accuracy of 20 tennis serves were measured approximately four hours after a morning split-body (lower legs and trunk) strength training session termed the lift-day (LD) and were compared to measures taken on days that no lifting took place, termed the non-lift day (NLD). For each test day, velocity was multiplied by accuracy to provide an overall serve performance …


The Effects Of Choice On Student Motivation And Physical Activity Behavior In Physical Education, Jillian Ward Mar 2005

The Effects Of Choice On Student Motivation And Physical Activity Behavior In Physical Education, Jillian Ward

Theses and Dissertations

Public school physical educators have the opportunity to help students understand the importance of engaging in regular physical activity in order to combat America's obesity problem. However, students are often unmotivated to participate in their physical education classes. Providing students with an autonomy supportive environment increases intrinsic motivation. Self-determination theory states that higher levels of intrinsic motivation should lead to an increase in behavior, or higher activity levels in a physical education class. This study examined (a) the effects of increased autonomy on self-determination, and (b) the effects of increased autonomy on physical activity levels. Seventh and eighth grade girls …


Effects Of Neuromuscular Training On The Dynamic Restraint Characteristics Of The Ankle, Christena Linford Mar 2005

Effects Of Neuromuscular Training On The Dynamic Restraint Characteristics Of The Ankle, Christena Linford

Theses and Dissertations

Objective: To examine the influence of a 6-week training program on the electromechanical delay (EMD) and reaction time of the peroneus longus muscle.

Design and Setting: The study was guided by a 2 x 2 factorial design with repeated measures on the time factor. The independent variables for this study were group (training and control) and time (pre- and post-training). Dependent variables for this study were muscle reaction time and electromechanical delay of the peroneus longus muscle.

Subjects: Thirty-six healthy, physically active, college-age (21.8 ± 2.3 yr) male and female (M = 14, F = 28, height = 173.7 ± …


The Impact Of A University Wellness Requirement On Student Nutrition And Physical Activity Behavior, Lisa Marie Blaser Mar 2005

The Impact Of A University Wellness Requirement On Student Nutrition And Physical Activity Behavior, Lisa Marie Blaser

Theses and Dissertations

Purpose: The Brigham Young University General Education Wellness Program has three options available to students to fulfill the programs requirement. The purpose of this study was to assess the impact of these three wellness options. Specifically we wanted to know; does the university wellness requirement affect student nutrition and physical activity behaviors and do the various options available differ in their abilities to impact student nutrition and physical activity behaviors?

Methods: A three-group pretest/posttest design was used and a survey was administered, at both the beginning and end of the semester, to all students enrolled in HEPE 129, live and …


Vegetation Response Of A Wyoming Big Sagebrush (Artemisia Tridentata Ssp. Wyomingensis) Community To 6 Mechanical Treatments In Rich County, Utah, Daniel David Summers Mar 2005

Vegetation Response Of A Wyoming Big Sagebrush (Artemisia Tridentata Ssp. Wyomingensis) Community To 6 Mechanical Treatments In Rich County, Utah, Daniel David Summers

Theses and Dissertations

In recent years, the importance of sagebrush to shrub-steppe ecosystems and associated plant and animal species has been recognized. The historical removal of herbaceous species by excessive and uncontrolled livestock grazing on many of our sagebrush ecosystems has resulted in a stagnant state where dense, competitive stands of sagebrush prevent herbaceous species from recovering. Most early research on sagebrush control was directed toward eradication to increase herbaceous forage for livestock production, rather than sagebrush thinning to improve shrub vigor and understory production for wildlife habitat and community diversity. Mechanical treatments have the ability to retain shrub and herbaceous components, while …