2000-2019

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Open Access
1 month effect of breaking up sedentary activity on insulin sensitivity and glucose homeostasis in free-living overweight/obese adults
(Colorado State University. Libraries, 2019) Schreck, Laura M., author; Hickey, Matthew, advisor; Bergouignan, Audrey, advisor; Broussard, Josiane, committee member; Melby, Christopher, committee member
Sedentary behavior (SB) triggers an inability to adjust substrate use to substrate availability (low metabolic flexibility, MF), which may precede glucose intolerance in the pathogenesis of insulin resistance. We and others have shown that frequent interruptions in SB leads to improved glycemic control, however the underlying role of MF in this process is unknown. This study examined the effects of breaking up SB on MF and glucose metabolism in free-living overweight and obese adults. To distinguish effects of breaking up SB from being physically active, we also studied a group where participants performed a single energy matched continuous bout of exercise. Physically inactive, adults (12F/9M, mean±SD, age: 33±8 yr, BMI: 29.5±3.3 kg/m2) were randomly assigned to a 4 week intervention consisting of brisk walking for 5 min each hour for 10h, 5 d/wk (MICRO, n=10), or 4 weeks of an intervention consisting of one continuous 45 min bout of exercise per day, 5d/wk (ONE, n=9). Outcomes assessed at baseline and after each intervention included: MF (waking respiratory quotient, RQ, minus sleeping RQ as measured in a whole room calorimeter), insulin sensitivity (SI, IVGTT), 24h glycemia (continuous glucose monitor), 24h glucose oxidation (U13C glucose tracer), SB, time spent standing, time spent stepping (ActivPAL) and TEE (double labeled water). Groups were similar on all outcome variables at baseline. Linear mixed models evaluated intervention and intervention-by-group effects. MICRO and ONE decreased time sitting and increased time stepping with no significant changes in TEE. Compared to ONE, MICRO decreased 24h glycemic variability (p=0.06), improved the acute whole body insulin sensitivity (p=0.08) and acute insulin response to glucose (AIRg) (p=0.02) , maintained exogenous glucose oxidation (p<0.03) and improved MF (p=0.02). Independent of time sitting and stepping, breaking up SB improves glucose homeostasis and MF. The effects of such an intervention in persons with type 2 diabetes warrants further study.
Open Access
[1,3]-oxygen to carbon rearrangement for the construction of carbon-carbon bonds between adjacent rings and 1,3-dioxepines in synthesis
(Colorado State University. Libraries, 2007) Frein, Jeffrey Daniel, author; Rovis, Tomislav, advisor
Several methods for the stereoselective formation of carbon-carbon bonds between contiguous rings where a stereogenic center is already present have been examined. The approaches investigated were: a [1,3]-oxygen to carbon rearrangement of cyclic vinyl acetals; an intermolecular enolsilane addition into an in situ generated oxocarbenium ion; an intramolecular conjugate addition of tethered alkoxy enones; and epimerization of several Î±-pyranyl cycloalkanones. These routes have been found to be complementary in several cases and have enabled formation of both the traps: anti and cis:anti stereoisomers in good to excellent yields and varying diastereoselectivities. The C2-C2' relative stereochemistry of the carbon-carbon bond between the adjacent rings was proven via a chemical correlation. The versatility of 1,3-dioxepines as precursors to the formation of 1,4-diols and 1,2,4-triols has been examined. The rapid synthesis of unsymmetrical 1,3-dioxepines and the installation of a 4-acetoxy substituent as a synthetic handle for further functionalization has been realized. The Lewis acid mediated addition into in situ generated oxocarbenium ions has been developed for variety of different nucleophiles. Furthermore, a highly trans -diastereoselective Heck reaction has been performed on unsymmetrical 1,3-dioxepines and their synthetic utility as precursors to the formation of 2,3,4-alkyl substituted tetrahydrofurans and 2-methoxy-4,5-alkyl substituted tetrahydrofurans have been exploited.
Open Access
3-chloro-p-toluidine hydrochloride metabolism and detection of exposure in birds
(Colorado State University. Libraries, 2017) Goldade, David A., author; Marie, Legare, advisor; William, Hannemann, advisor; Gregory, Dooley, committee member; Gary, Mason, committee member
The avicide 3-chloro-4-methylanaline hydrochloride (chloro-p-toluidine hydrochloride, CPTH, DRC-1339) is used to control pest bird species that damage agricultural crops. While it is theorized that CPTH is a nephrotoxin, no definitive assessment of the mode of action has been performed. Additionally, the metabolic pathway of CPTH in birds has yet to be elucidated. Radioactively labeled [14C]-3-chloro-4-methylaniline hydrochloride (250 µg per bird) was delivered to 21 red-winged blackbirds (Agelaius phoeniceus) and 21 dark-eyed juncos (Junco hyemalis) via oral gavage, and the distribution and excretion of radioactivity were determined at 15 and 30 minutes and 1, 4, 8, 12, and 24 hours (n = 3 per time point). Direct measurement of radioactivity as well as measurement following combustion was accomplished using a liquid scintillation counter. Elimination from most tissues followed a two-compartment model, with very rapid elimination occurring between time 0 and 4 hours and a much slower elimination phase occurring after that. The average half-life of elimination for the initial phase in most tissues examined was 0.16 hours for juncos and 0.62 hours for blackbirds. The average for the slower second phase of elimination was 3.4 hours for juncos and 5.4 hours for blackbirds. The radioactivity in blackbird kidney tissues did not change significantly for the duration of the test, pointing toward the kidney as a possible site of action for this important agricultural chemical. To further explore the mechanistic toxicology of CPTH, sub-cellular preparations were made from the liver and kidney of various avian species. In-vitro metabolism experiments were performed using these preparations and the resulting metabolites were identified and quantified. Two metabolites were identified: 3-chloro-4-methylacetanilide (CAT) and N-[3-chloro-4-(hydroxymethyl)phenyl]acetamide (OH-CAT). A comparison of two methods was made for the analysis of CPTH and its metabolites. Due primarily to the solubility and volatility of the three compounds, CPTH and CAT performed well on gas chromatography tandem mass spectrometry (GC/MS/MS) and adequately on liquid chromatography tandem mass spectrometry (LC/MS/MS). Conversely, OH-CAT performed optimally on LC/MS/MS. LC/MS/MS was chosen as the technique for analysis of exposure data. Both methods generated residue values that demonstrated a high degree of variability between individuals. Despite the variability issues, the data showed that the primary chemical species present in the tissues of exposed birds was OH-CAT, and that the concentration of observed residue was related to the dose administered. In an effort to identify the target for tissue binding of CPTH or its metabolites in the kidney of exposed red-winged blackbirds, protein samples were extracted and digested with trypsin. Several chemical compounds were found to be significantly different between treated and control groups (α=0.05) and were subjected to tandem mass spectrometry to identify their chemical structure. Results from this analysis did not yield any identification of specific protein binding. Limitations of sensitivity and lack of sample enrichment likely led to this outcome.
Open Access
5-hydroxymethylcytosine and endonuclease G as regulators of homologous recombination
(Colorado State University. Libraries, 2017) Vander Zanden, Crystal M., author; Ho, P. Shing, advisor; Peersen, Olve, committee member; Di Pietro, Santiago, committee member; Fisk, Nick, committee member
Homologous recombination (HR) is a necessary biological process for all living organisms, and it is especially important for repairing damaged DNA. Improper HR results in DNA damage-related diseases, notably increased likelihood of cancer when HR regulators, such as the human BRCA1 gene, are impaired. HR is also a tool for biotechnology, giving scientists the power to easily delete or mutate genes and study the effects of those modifications. Recently, the epigenetically modified nucleotide 5-hydroxymethylcytosine (5hmC) was found to regulate vertebrate HR via interaction with the protein endonuclease G (EndoG). In this dissertation, I use biochemical/biophysical methods to elucidate the interaction between 5hmC and EndoG, thus working towards understanding their roles as regulators of recombination. I find that 5hmC forms a unique hydrogen bond to stabilize Holliday junctions, the four-stranded DNA intermediate in HR. 5hmC also induces a global structure change to the junction, increasing protein access to the junction crossover and providing potential for either direct or indirect readout of 5hmC. Further connecting EndoG with recombination, we present the first evidence that EndoG preferentially binds and cleaves Holliday junction DNA, implicating a role for EndoG as a resolvase. I demonstrate that EndoG recognizes 5hmC in the junction context and observe unique cleavage products from EndoG interaction with 5hmC-junctions. These results suggest that EndoG may have a previously unrecognized junction resolvase function and, in this way, play a more direct role in recombination than simply creating double-stranded breaks in duplex DNA to initiate the HR mechanism. Finally, I present a unique structural feature of vertebrate EndoG that we hypothesize is the basis for 5hmC recognition. I present the structure of mouse EndoG and propose that a two amino acid deletion, conserved in vertebrate EndoG sequences, is associated with unraveling of an α-helix. This structural perturbation positions amino acid side chains to confer 5hmC-sensing ability to all vertebrate EndoG. I expect that these deletion mutations and resulting structural effects co-evolved with the appearance of 5hmC in vertebrate genomes to give EndoG an additional function of recognizing 5hmC in the cell. Overall this work is building onto the understanding of 5hmC and EndoG as markers and regulators of recombination.
Open Access
5MF6255: excavations at an early archaic basin house site in the Yampa River Valley, Moffat County, Colorado
(Colorado State University. Libraries, 2010) Slaughter, Stephanie, author; LaBelle, Jason, advisor; Zeidler, James, committee member; Fiege, Mark T., committee member
Metcalf Archaeological Consultants, Inc., excavated site 5ME6255 in the late summer and early fall of 2006. The site had been discovered during the open trench inspection of Wyoming Interstate Company’s Piceance Basin Expansion Project pipeline. As observed in the trench, the site contained a dark cultural stain located about 1.6 m below bladed surface, which was identified as a possible basin house. Its stratigraphic position within a zone of heavy calcium carbonate deposits suggested an age of 7000 BP or greater, placing the site firmly within the Pioneer period of the Archaic era. Very few sites of this age have been excavated in northwestern Colorado, making 5MF6255 important for establishing basic information about this period of prehistory, regardless of whether or not it was a basin house. A total of 104 complete and partial 1 m by 1 m units were excavated in one large block to explore the contextual integrity of the feature, the nature of the stain, and search for any associated ancillary features. Results of excavation revealed the site consisted of three basin houses, one of which had two rooms, as well as 15 other pit features. A preliminary charcoal sample from the upper layers of the south end of the initially identified basin house was submitted for radiocarbon analysis and returned two intercept dates of 7935-8070 cal BP and 8084-8159 cal BP (2-sigma), dating the site to the early Pioneer Period of the Archaic Era. It is one of the oldest basin house known in the northern Colorado River basin area. Cultural material recovered from the site is described, and the research contributions resulting from these investigations are detailed, iii including its place in the chronology of northwestern Colorado, paleoenvironmental data obtained for the project as a whole is described, settlement and subsistence strategies are discussed, and finally, morphology of both the house features and pit features are detailed. A short comparison of this site to other Pioneer-era sites in the regions is also discussed, placing the site within the context of the larger early Archaic adaptive strategies of the region.
Open Access
A balance of design methodology for enterprise quality attribute consideration in System-of-Systems architecting
(Colorado State University. Libraries, 2019) Nelson, Travis J., author; Borky, John M., advisor; Sega, Ronald M., advisor; Bradley, Thomas K., committee member; Roberts, Nicholas H., committee member
An objective of System-of-Systems (SoS) engineering work in the Defense community is to ensure optimal delivery of operational capabilities to warfighters in the face of finite resources and constantly changing conditions. Assurance of enterprise-level capabilities for operational users in the Defense community presents a challenge for acquisitions in balancing multiple SoS architectures versus the more traditional system-based optimization. The problem is exacerbated by the complexity of SoS being realized by multiple, heterogeneous, independently-managed systems that interact to provide these capabilities. Furthermore, the comparison of candidate SoS architectures for selection of the design that satisfies the most enterprise-level objectives and how such decisions affect the future solution space lead to additional challenges in applying existing frameworks. As a result of the enormous challenge associated with enterprise capability development, this research proposes an enterprise architecting methodology leveraging SoS architecture data in the context of multiple enterprise-level objectives to enable the definition of candidate architectures for comparison and decision-making. In this context, architecture-based quality attributes of the enterprise (e.g., resilience, agility, changeability) must be considered. This research builds and extends previous SoS engineering work in the Department of Defense (DoD) to develop a process framework that can improve the analysis of architectural attributes within an enterprise. Certain system attributes of interest are quantified using selected Quality Attributes (QAts). The proposed process framework enables the identification of the quality attributes of interest as the desired characteristics to be balanced against performance measures. QAts are used to derive operational activities as well as design techniques for employment against an as-is SoS architecture. These activities and techniques are then mapped to metrics used to compare alternative architectures. These alternatives enable an SoS-based balance of design for performance and quality attribute optimization while employing a capability model to provide a comparison of available alternatives against overarching preferences. Approaches are then examined to analyze performance of the alternatives in meeting the enterprise capability objectives. These results are synthesized to enable an analysis of alternatives (AoA) to produce a "should-be" architecture vector based on a selected "to-be" architecture. A comparison of the vector trade space is discussed as a forward work in relation to the original enterprise level objectives for decision-making. The framework is illustrated using three case studies including a DoD Satellite Communications (SATCOM) case study; Position, Navigation, and Timing (PNT) case study; and a satellite operations "as-a-service" case study. For the SATCOM case study specifically, the question is considered of whether a certain QAt—resilience—can best be achieved through design alternatives of satellite disaggregation or diversification. The analysis shows that based on the metric mapping and design alternatives examined, diversification provides the greatest SATCOM capability improvement compared to the base architecture, while also enhancing resilience. These three separate cases studies show the framework can be extended to address multiple similar issues with system characteristics and SoS architecture questions for a wide range of enterprises.
Open Access
A bewitching semblance of something to be desired: advertising nostalgia and product involvement's relative influence on attitudes and purchase intent among young adults
(Colorado State University. Libraries, 2014) Bray, Matthew T., author; Hallahan, Kirk, advisor; Long, Marilee, committee member; Donavan, Todd, committee member
Despite the recent rise of advertisements employing nostalgia, relatively few previous studies have investigated the effectiveness of nostalgic messages, especially as they might be applied to promote high- versus low-involvement products. Previous research has broadly conceptualized nostalgia without focusing on product-related or associational claims. This research used associational nostalgia where the nostalgic themes presented in the advertisements were not directly related to previous product usage. A quasi-experiment involving a convenience sample of undergraduates (n=201) in a large classroom setting was used to compare the effects of nostalgic versus non-nostalgic messages in ads for a fictitious high involvement product (laptop computer) and a fictitious low involvement product (paper notebooks). Participants were randomly assigned to one of four experimental conditions and read a single ad. Product knowledge for laptops and notebooks (and two distractor products) were measured in a pretest questionnaire; dependent measures in the posttest results were measured in terms of three dependent measures: attitude toward the ad, attitude toward the brand, and purchase intent. Additionally, because previous research has yet to determine how nostalgic advertising is most likely to be cognitively processed, open-ended cognitive response items were also included to further investigate the type of processing that is most frequently occurring. Gender was included as a possible moderating variable. The results provide mixed support for the hypothesized relationships between product involvement and nostalgic advertising themes. Findings suggest that females are particularly responsive, in terms of attitude toward the ad and attitude toward the brand, to associational nostalgic claims for the low involvement product (notebooks). Cognitive response-thought listing results suggest that when the primary thought elicited from the advertisement was nostalgic in nature, other references to the product or the ad itself decreased. Implication and practical considerations for content creators in advertising as well as future research suggestions are also discussed.
Open Access
A binary approach to the analysis of prehistoric bison distribution and paleoecology in northern Colorado and southern Wyoming
(Colorado State University. Libraries, 2014) McKetta, Suzanne B., author; LaBelle, Jason M., advisor; Glantz, Mica, committee member; Cotrufo, Francesca, committee member
Bison exploitation is at the heart of prehistoric hunter-gatherer subsistence on the Great Plains and can reveal robust information regarding patterns of migration, chronology, and variability in paleoclimate. However, despite association with human subsistence practices, bison population and distribution patterns across time and space are unclear. This thesis presents a study of prehistoric bison distribution and population ecology in archaeological and natural contexts in northern Colorado and southern Wyoming. Two methods are used here to reconstruct the diet and distributions of prehistoric bison populations. The first method involves identifying the known distribution of bison in archaeological and natural settings in the study area through an analysis of archival documentation. Cultural chronologies based on archaeological associations have long been valuable in regional research, but can be imprecise and of insufficient resolution for constructing detailed sequences of prehistoric events. Therefore, to expand knowledge of the regional archaeological distribution of bison, this research utilized a total of 272 archaeological sites containing faunal remains. In addition, 291 calibrated radiocarbon dates were used to compile and analyze bison presence and absence through sum probability distributions and statistical analyses. The second method explores the paleoecology of bison through the use of carbon (13C/12C) and nitrogen (15N/14N) stable isotopes analysis of bone collagen from 35 prehistoric bison specimens. Stable isotopes analysis helps to characterize bison distribution and ecology through reconstruction of bison dietary forage and is compared with paleoclimate data in order to identify trends in bison migration and population patterns. This study adds significant chronological information to the regional record of bison presence in northern Colorado and southern Wyoming and helps to correlate bison distribution patterns with the paleoclimate record.
Open Access
A binding deficit: value-directed remembering for item-specific vs. associative information
(Colorado State University. Libraries, 2018) DeLozier, Sarah J., author; Rhodes, Matthew G., advisor; Davalos, Deana, committee member; Folkestad, James, committee member; Cleary, Anne, committee member
In a series of four experiments I examined whether value enhanced memory for item-specific or associative information. Value indicated the importance of an item at study (i.e., 1 point = low importance, 12 points = high importance), with memory typically being enhanced for high-value information (e.g., Castel, 2008). Utilizing the feature-conjunction paradigm, in which recognition errors for conjunction lures provide a means of examining whether value-enhanced recognition is a result of recollection or familiarity, the Pilot Experiment revealed through increased conjunction errors that value enhanced memory only for item-specific information. In Experiment 1 participants were permitted to self-pace their study and made confidence learning judgments (CLJs) after each recognition judgment. Learners spent more time studying higher-valued words yet demonstrated a similar pattern of increased conjunction errors by value. In Experiment 2, participants were instructed to use either rote repetition or interactive imagery for all words at study. Under these controlled study strategy conditions, conjunction errors were similar across values. In Experiment 3, I examined the influence of value on feature lures. When both feature lures and conjunction lures were presented at test, learners' susceptibility to lures was similar across values, yet learners correctly recognized more high-value old words. Results indicated that both encoding processes and item-based familiarity may contribute to a deficit in binding components of high-value words. These findings are discussed in terms of the negative effects of value on memory for associative information.
Open Access
A biocultural examination of trauma from the Colorado State Insane Asylum skeletal collection, 1879-1899
(Colorado State University. Libraries, 2011) Leavitt-Reynolds, Alissa Anne, author; Magennis, Ann L., advisor; Van Buren, Mary, committee member; Fiege, Mark T., committee member
This thesis uses a biocultural approach to study skeletal trauma present in the Colorado State Insane Asylum (CSIA) Skeletal Collection from 1879 to 1899. The biocultural approach utilizes both the physical remains and historic documentary material present for this collection to connect the skeletal findings with the cultural environment in which the individuals lived and died. Of the 166 individuals present (both complete and incomplete), 69% in the collection show at least one instance of trauma, while 31% show no evidence of trauma. This trauma rate includes both fractures and dislocations, or acute trauma, in addition to chronic trauma (Schmorl's Nodes). Males have the highest traumatic injury rates, with 40% of the sample having one or more fractures or dislocations. Females show a rate of 29% for acute trauma, while indeterminate sex individuals have a rate of 38%. The trauma results were then compared with contemporary, mostly Euroamerican, skeletal collections from the Albany Almshouse and the Oneida Asylum in New York to reveal that while all three institutions show similar rates of chronic trauma, the CSIA Collection has much higher rates of acute trauma -- nearly double that of the other populations. Ultimately, the analysis of trauma as undertaken in this research provides yet another line of evidence to better understand and contextualize the health and health risks of individuals and populations from the nineteenth-century American West, and more specifically, those in institutionalized care during that time.
Open Access
A bioeconomic and general equilibrium framework to address fishery management and invasive species
(Colorado State University. Libraries, 2017) Apriesnig, Jenny L., author; Goemans, Christopher, advisor; Warziniack, Travis, advisor; Manning, Dale, committee member; Thilmany, Dawn, committee member; Johnson, Brett, committee member
Fisheries management is a complex issue that involves the management of people, fish populations and habitat. There are many facets to fishery issues including ownership, regulation, and environmental change. I address all three of these facets in the following work. I develop a general equilibrium model that incorporates fish stock and present two applications of it. I evaluate the change of a fishery under a regulated open access regime to an individual transferrable quota system. I apply the model to the Lake Erie yellow perch fishery, and I account for the different allocations of the value provided by the fish stock, and the potential changes in efficiency. I find that the change to an individual transferrable quota system results in welfare improvements but only if the individual transferrable quota system induces improved catchability and efficiency in fishery effort choices. I also develop an integrated bioeconomic model with the general equilibrium framework to evaluate the joint responses of a regional economy and lake food web to an environmental shock. The model is unique in that there are feedbacks between the economy and food web. The bioeconomic model is used to evaluate a potential Lake Erie Asian carp invasion. There are two primary results from the analysis; the Asian carp invasion leads to welfare improvements, and when invasion impacts are estimated with only the ecological food web model, without the consideration of changes in human choice, the impacts to some fish populations are overestimated while others are underestimated. In both applications, I show that using a general equilibrium framework captures welfare impacts that would be missed by a partial equilibrium analysis.
Open Access
A biographical study of namesake John F. Tinker on the landmark legal case Tinker et al. v. The Des Moines Independent Community School District et al.
(Colorado State University. Libraries, 2008) Wolfe-Dawson, Leigh, author; Harbour, Clifford P., advisor
The purpose of this biographical study was to understand the effect of the case Tinker et al. v. The Des Moines Independent Community School District et al. circa 1965-1969, on namesake John F. Tinker, circa 2008. John Tinker was involved in a landmark 1969 United States Supreme Court decision nearly 40 years ago. He was 15 years old when he wore a black armband to school to protest the Vietnam War; he is 57 now. In legal and educational environments, Tinker is known as a name on a school-related legal decision, but there is a person behind that name. While there is abundant information about his legal case, not much is known about the namesake. This study attempted to understand how Tinker experienced his legal case and how he understands its effect on his life. This study centered on John Tinker's own voice. Through in-depth, open-ended, one-on-one, face-to-face, voice-to-voice, and computer-to-computer conversations, an account of his life using his own words emerged. What was discovered was that Tinker is a multi-faceted person and the Tinker legal case is only one aspect of his full and unique life. This study is important because Tinker is a living being who as a teenager was involved in an activity that culminated in a landmark decision by the United States Supreme Court. That legal decision holds today-40 years later-and affects every public school student in the United States.
Open Access
A biomechanical analysis of venous tissue in its normal, post-phlebitic, and genetically altered conditions
(Colorado State University. Libraries, 2009) McGilvray, Kirk Cameron, author; Puttlitz, Christian M., advisor
The incidence of vein disease is very high, affecting more than 2% of the hospitalized patients in the United States; a number that is expected to increase. Post phlebitic veins, the result of chronic deep vein thrombosis, is considered to be one of the most important venous disease pathologies. Unfortunately, little information is currently available on the biomechanical effects of thrombus resolution in the deep veins. The aim of this research was to characterize the biomechanical response of both healthy and diseased venous tissue using a murine model. It was hypothesized that biomechanical response parameters derived from healthy and diseased tissue would give insight into the resultant clinical complications observed in patients following thrombus resolution. Biomechanical analysis revealed that statistically significant deleterious changes in vein wall compliance were observed following thrombus resolution. Data also revealed that matrix metallopeptidase 9 expression has a statistically significant effect on the biomechanical response of the tissue. These results indicate that clinical complications following deep venous thrombosis manifest from significant decreases in the compliance of the vein wall. Finite element analyses were also performed. Biomechanical data served as input material parameters for modeling. Finite element modeling was used to evaluate the response of the inferior vena cava under physiologic loads. The results indicate that peak stresses are generated in the circumferential direction of loading during luminal pressurization. Decreased dilatation was observed following thrombus resolution. The data indicates that deep venous thrombosis lead to increased vein wall stress in correlation with decreased luminal distensability.
Open Access
A biosensor system with an integrated CMOS microelectrode array for high spatio-temporal electrochemical imaging
(Colorado State University. Libraries, 2019) Tedjo, William, author; Chen, Thomas, advisor; Tobet, Stuart, committee member; Collins, George, committee member; Wilson, Jesse, committee member
The ability to view biological events in real time has contributed significantly to research in life sciences. While optical microscopy is important to observe anatomical and morphological changes, it is equally important to capture real-time two-dimensional (2D) chemical activities that drive the bio-sample behaviors. The existing chemical sensing methods (i.e. optical photoluminescence, magnetic resonance, and scanning electrochemical), are well-established and optimized for existing ex vivo or in vitro analyses. However, such methods also present various limitations in resolution, real-time performance, and costs. Electrochemical method has been advantageous to life sciences by supporting studies and discoveries in neurotransmitter signaling and metabolic activities in biological samples. In the meantime, the integration of Microelectrode Array (MEA) and Complementary-Metal-Oxide-Semiconductor (CMOS) technology to the electrochemical method provides biosensing capabilities with high spatial and temporal resolutions. This work discusses three related subtopics in this specific order: improvements to an electrochemical imaging system with 8,192 sensing points for neurotransmitter sensing; comprehensive design processes of an electrochemical imaging system with 16,064 sensing points based on the previous system; and the application of the system for imaging oxygen concentration gradients in metabolizing bovine oocytes. The first attempt of high spatial electrochemical imaging was based on an integrated CMOS microchip with 8,192 configurable Pt surface electrodes, on-chip potentiostat, on-chip control logic, and a microfluidic device designed to support ex vivo tissue experimentation. Using norepinephrine as a target analyte for proof of concept, the system is capable of differentiating concentrations of norepinephrine as low as 8µM and up to 1,024 µM with a linear response and a spatial resolution of 25.5×30.4μm. Electrochemical imaging was performed using murine adrenal tissue as a biological model and successfully showed caffeine-stimulated release of catecholamines from live slices of adrenal tissue with desired spatial and temporal resolutions. This system demonstrates the capability of an electrochemical imaging system capable of capturing changes in chemical gradients in live tissue slices. An enhanced system was designed and implemented in a CMOS microchip based on the previous generation. The enhanced CMOS microchip has an expanded sensing area of 3.6×3.6mm containing 16,064 Pt electrodes and the associated 16,064 integrated read channels. The novel three-electrode electrochemical sensor system designed at 27.5×27.5µm pitch enables spatially dense cellular level chemical gradient imaging. The noise level of the on-chip read channels allow amperometric linear detection of neurotransmitter (norepinephrine) concentrations from 4µM to 512µM with 4.7pA/µM sensitivity (R=0.98). Electrochemical response to dissolved oxygen concentration or oxygen partial pressure (pO2) was also characterized with deoxygenated deionized water containing 10µM to 165 µM pO2 with 8.21pA/µM sensitivity (R=0.89). The enhanced biosensor system also demonstrates selectivity to different target analytes using cyclic voltammetry to simultaneously detect NE and uric acid. In addition, a custom-designed indium tin oxide and Au glass electrode is integrated into the microfluidic support system to enable pH measurement, ensuring viability of bio-samples in ex vivo experiments. Electrochemical images confirm the spatiotemporal performance at four frames per second while maintaining the sensitivity to target analytes. The overall system is controlled and continuously monitored by a custom-designed user interface, which is optimized for real-time high spatiotemporal resolution chemical bioimaging. It is well known that physiological events related to oxygen concentration gradients provide valuable information to determine the state of metabolizing biological cells. Utilizing the CMOS microchip with 16,064 Pt MEA and an improved three-electrode system configuration, the system is capable of imaging low oxygen concentration with limit of detection of 18.3µM, 0.58mg/L, or 13.8mmHg. A modified microfluidic support system allows convenient bio-sample handling and delivery to the MEA surface for sensing. In vitro oxygen imaging experiments were performed using bovine cumulus-oocytes-complexes cells with custom software algorithms to analyze its flux density and oxygen consumption rate. The imaging results are processed and presented as 2D heatmaps, representing the dissolved oxygen concentration in the immediate proximity of the cell. The 2D images and analysis of oxygen consumption provide a unique insight into the spatial and temporal dynamics of cell metabolism.
Open Access
A bricolage of narratives about teaching college in prison: interpreting through a performance text
(Colorado State University. Libraries, 2008) Spaulding, Susanna Belle, author; Harbour, Clifford P., advisor
The purpose of this narrative inquiry was to explore and understand how a selected group of educators made meaning of their experiences teaching college courses in prison. This phenomenon was framed by the tension between two contrasting conceptualizations of education: education as a means of social control and education as the practice of freedom. The data were in-depth stories collected from a small number of participants through unstructured interviews. As I identified narrative structures from my interview transcripts for analysis, three transcendent themes emerged that I used to create a coherent composite story, or bricolage, about these lived experiences. Using a feminist lens, I examined how these educators worked in a borderland, negotiated power relations within this environment, and made personal transformations. To convey an impression of these real-life experiences, I presented the data in a performance text leaving intact large segments of my participants' interview dialogue. The prison offered a rich discursive environment for this study since its hierarchical power structure that focuses on social control contrasts with the democratic classroom that the participants attempted to create. Within the stormy, dangerous, and frustrating prison setting, these educators encountered unique situations for which they were often unprepared and were caught between competing conceptualizations of education.
Open Access
A Burkean analysis of the Common Core State Standards: revealing motive by analyzing the agent-purpose ratio and critiquing the standards with a postcolonial lens
(Colorado State University. Libraries, 2014) Lemming, Megan C., author; Kiefer, Kathleen, advisor; Coke, Pamela, committee member; Aragon, Antonette, committee member
Public schooling in the United States undergoes frequent, large-scale reforms based on current political, social, and economic conditions. Such conditions influence the demand for students to master particular literacies and discourses. The Common Core State Standards, a recent educational reform measure that has been adopted by forty-six states, indicate what students need to know and be able to do at the end of each grade level in certain content areas. Examining particular aspects of the Common Core State Standards, such as the agents involved and their purpose in creating and implementing the Standards, helps to reveal implicit motives driving the implementation of the Common Core State Standards. This thesis seeks to reveal such motives in order to illuminate which literacies, literacy practices, and discourses are privileged in public schooling today. My findings indicate that the Common Core reinforces a Western, hegemonic, patriarchal discourse, which has the potential to Other non-dominant discourses and alienate students belonging to marginalized populations. Space exists, however, for teachers to employ pedagogies and methods that challenge this discourse, which ultimately can increase student agency and promote the democratic ideals of public education.
Open Access
A calcium aluminate electride hollow cathode
(Colorado State University. Libraries, 2014) Rand, Lauren Paula, author; Williams, John, advisor; Reynolds, Melissa, committee member; Sampath, Walajabad, committee member; Yalin, Azer, committee member
The development and testing of a hollow cathode utilizing C12A7 (12CaO.Al2O3) electride as an insert are presented. Hollow cathodes are an integral part of electric propulsion thrusters on satellites and ground-based plasma sources for materials engineering. The power efficiency and durability of these components are critical, especially when used in flight applications. A low work function material internal to the cathode supplies the electrons needed to create the cathode plasma. Current state-of-the- art insert materials are either susceptible to poisoning or need to be heated to temperatures that result in a shortened cathode lifetime. C12A7 electride is a ceramic in which electrons contained in sub-nanometer sized lattice cages act as a conductive medium. Due to its unique atomic structure and large size, C12A7 electride has a predicted work function much lower than traditional insert materials. A novel, one-step fabrication process was developed that produced an amorphous form of C12A7 electride that had a measured work function 0.76 eV. A single electride hollow cathode was operated on xenon for over 60 hours over a two-month period that included 20 restarts and 11 chamber vent pump-down sequences with no sign of degradation, and on iodine for over 20 hours with no apparent reactivity issues. The operations of cathodes with three different orifice sizes were compared, and their effects on the interior cathode plasma modeled in a zero- dimensional phenomenological model.
Open Access
A case study evaluation of edible plants curriculum implemented in an elementary school
(Colorado State University. Libraries, 2014) Graves, Leila, author; Hughes, Harrison, advisor; Balgopal, Meena, advisor; Bunning, Marisa, committee member; Krishnan, Sarada, committee member
The main purpose of this study was to describe elementary teachers' attitudes and perceptions toward plant science. The secondary purpose was to create an edible plant curriculum as a vehicle for integrating STEM and 21st Century skills into Common Core Content. Results indicate that teachers and STEM coordinators did find the curriculum to be effective in teaching the interdisciplinary standard-based and inquiry based content and skills targeted. Additionally, the curriculum development process produced a hybrid design framework that facilitated the creation of life science content as a vehicle for integrating STEM into common core content. However, several significant barriers will need to be overcome with regard to the teachers', STEM coordinators' and administrators' perception that plant science and nutrition literacy are "special" content activities versus important STEM content.
Open Access
A case study of a wheat-free diet on autoimmune disease progression
(Colorado State University. Libraries, 2014) Connor, Trevor, author; Cordain, Loren, advisor; Hickey, Matthew, committee member; Ryan, Elizabeth, committee member; Schenkel, Alan, committee member
Background and Aims: Autoimmune disease encompasses a broad range of over 80 conditions for which only three have an identified environmental trigger. Gliadin is the trigger in celiac disease, a condition that has been linked to other autoimmune conditions including Crohn's disease and type I diabetes (T1D). The purpose of this study was to investigate case studies of autoimmune patients who employed a wheat-free or Paleo-style diet (WFP) to manage their conditions. Methods: A descriptive case study was performed that utilized questionnaires administered online and medical records from autoimmune disease patients who had consumed a WFP diet. Results: Fifty-seven patients were evaluated in the study (mean age 37.3 yrs., SD 10.1), including 23 males and 34 females, 24 of whom provided medical records. Thirty of the 57 volunteers demonstrated signs of disease improvement while consuming a WFP. The rates varied across conditions with eight of eight Crohn's disease patients experiencing remission, while three of four T1D patients exhibited signs of improvement. Five of 15 patients with ankylosing spondylitis, rheumatoid arthritis, or undifferentiated and multiple connective tissue disorders worsened while on the diet. Conclusions: Patients with single organ autoimmune diseases previously linked to increased intestinal permeability showed the greatest improvement after consuming a WFP. The results of these case studies warrant further controlled research examining the effects of wheat consumption on Crohn's disease and T1D.
Open Access
A case study of barriers inhibiting the growth of information and communication technology (ICT) in a construction firm
(Colorado State University. Libraries, 2017) Andipakula, Thejasvi, author; Senior, Bolivar A., advisor; Nobe, Mary, committee member; Skiba, Hilla, committee member
The purpose of this research is to study barriers that inhibit the growth of ICT in a construction firm operating in the state of Nevada. This paper focusses on three research objectives. The first research objective is to identify commonly used Information and communication technology tools in the selected firm. The second objective is to highlight significant barriers that hinder the growth of ICT implementation in the selected construction firm. The third research objective is to analyze strategies used by professionals of the selected construction firm for mitigating barriers that are encountered while attempting to implement ICT. Different factors were highlighted which inhibit the growth of ICT. Literature review highlighted the most important ones as financial constraints, time constraints, lack of support from top management, lack of training, the reluctance of employees to learn new technology and lack of technical support. To mitigate the barriers to ICT adoption, literature has stated different strategies. These include support and encouragement from top management, training employees for ICT tools, motivating employees for using ICT, empowering a champion to overcome resistance from employees, learning by observation and giving employees sufficient time to learn. A case study approach was used, and one firm was the center of research, thereby data collection and analysis was limited to this particular firm. Nine interviews were conducted with employees belonging to different sectors in which firm operates. A thematic analysis of interview data was conducted using NVivo. Roger's model of Innovation Diffusion (1983) was employed as a tool for considering ICT adoption attitudes in terms of the interviewees' personal preferences. The analysis showed that all interviewees had a clear understanding of importance and scope of ICT in the selected firm. However, their understanding was congruent with their stage of Roger's model (1983). The selected firm had the financial strength to adopt ICT, and top management supported new ideas and ICT adoption. Ample training was given to employees so that they can learn new technology with ease. A persistent barrier was the time available to implement ICT, as interviewees reported that they needed more time to explore the use of new technologies. The selected firm used three strategies to facilitate ICT diffusion, i.e., training employees, motivating them and creating a culture of support. It was suggested that the selected firm should use 'learning by observation'; showing employees how ICT can help with their day-to-day work will motivate them and develop their interest in using it. Furthermore, giving employees time to explore the use of new technologies can also facilitate ICT implementation in the selected firm. The implications of findings for the selected firm and other firms in the construction sector are discussed in the thesis.