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

Digital Commons Network™

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

Theses and Dissertations

Discipline
Institution
Keyword
Publication Year
File Type

Articles 15961 - 15990 of 19641

Full-Text Articles in Entire DC Network

Identification Of Potential Organic Contributors In Carbonaceous Aerosols: Enhanced Uv Absorption Spectra, Anand Mangu Jan 2007

Identification Of Potential Organic Contributors In Carbonaceous Aerosols: Enhanced Uv Absorption Spectra, Anand Mangu

Theses and Dissertations

Direct aerosol climate effects include light scattering and absorption that present the largest uncertainties in the assessment of radiative forcing. To estimate the overall effect of aerosols on climate the relative amounts of scattering and absorption must be known. Determination of aerosol UV-absorption spectra is the primary focus of this thesis research. Aerosol samples were collected in Mexico City in 2003 and 2006 as a part of Mexico City Metropolitan Area field study and also at Little Rock. UV-visible absorption spectra of these aerosol samples have been obtained by using an integrating sphere coupled to a UV-visible spectrometer and compared …

Go to article

Load Distribution And Channel Assignment In Ieee 802.11 Wireless Local Area Networks, Mohamad Haidar Jan 2007

Load Distribution And Channel Assignment In Ieee 802.11 Wireless Local Area Networks, Mohamad Haidar

Theses and Dissertations

Recent growth in Wireless Local Area Network (WLAN) deployment has generated considerable interest in load management and channel assignment among network designers. WLAN has become a major component of the modern telecommunication infrastructure. Load management and Channel assignment are among the critical aspects that face WLAN deployments. Well planned WLAN service environments require a network designed to provide not only radio coverage but also better load distribution and less interference across the service area, which in turn improves the Quality of Service (QoS). In this dissertation, a novel approach to the WLAN load distribution and channel assignment is proposed that …

Go to article

Mining Frequent Patterns From Sequences: Theory, Algorithm, Implementation, And Performance, Markus Petteri Turkia Jan 2007

Mining Frequent Patterns From Sequences: Theory, Algorithm, Implementation, And Performance, Markus Petteri Turkia

Theses and Dissertations

Mining frequent patterns from sequences is an important data mining problem which has direct applications in many areas. In this thesis, we make three contributions to the state-of-the-art of the sequential frequent pattern mining. First of all, we propose a fast pattern-growth mining algorithm using a novel sequence database representation called First-Occurrence Linked WAP-tree (FLWAP-tree). The pattern-growth mining algorithm using the Pre-Order Linked WAP-tree (PLWAP-tree) was reported in the literature to be faster than other algorithms. We show that our pattern-growth using our FLWAP-tree outperforms the PLWAP-tree mining significantly and consistently. Secondly, we extend the pattern-growth algorithm with partial enumeration …

Go to article

Short-Term Reliability Of A Thin Film Resistance Temperature Detector (Rtd), Julian W. Post, Jr. Jan 2007

Short-Term Reliability Of A Thin Film Resistance Temperature Detector (Rtd), Julian W. Post, Jr.

Theses and Dissertations

The primary focus of this dissertation was on the short term reliability of a thin film resistance temperature detector (RTD). As a first step, the transient and steady state temperature response of an encapsulated, thin-film RTD, which was used as a micro heater, have been characterized for a range of pressures and applied voltages, while placed on thermally insulating and conductive platforms. A user-friendly model was used to capture the three major mechanisms of heat transfer from the device (i.e. conduction, convection, and radiation). The calibration parameters of the model allowed the different modes of heat transfer to be quantified. …

Go to article

Synthesis And Characterization Of Highly Conductive Polypyrrole And Polypyrrole/Lignosulfonate/Graphite Composites, Aopeau Imvittaya Jan 2007

Synthesis And Characterization Of Highly Conductive Polypyrrole And Polypyrrole/Lignosulfonate/Graphite Composites, Aopeau Imvittaya

Theses and Dissertations

Polypyrrole (PPy) is one of the conductive polymers frequently used in commercial applications, mainly due to its long-term stability and the possibility of forming homopolymers or composites with optimal properties. Polypyrroles were prepared by the chemical polymerization of pyrrole using various methods. The effects of several parameters such as oxidant, dopant type, additives and reaction conditions on the properties of PPy were investigated. In addition, PPy/graphite composites were prepared because graphite is highly conductive and effectively incorporated into the polymer matrix during the polymerization. The amount of graphite in the composite was varied to determine the maximimum conductivity achievable in …

Go to article

The Abc's Of Early Intervention: Assessing The Arkansas Better Chance For School Success Pre -School Program, Lisa Walker Todd Jan 2007

The Abc's Of Early Intervention: Assessing The Arkansas Better Chance For School Success Pre -School Program, Lisa Walker Todd

Theses and Dissertations

Early intervention programs have long been associated with increased cognitive benefits for disadvantaged poverty children. The Arkansas Better Chance for School Success Pre-school Program (ABCSS) was implemented in select counties in Arkansas as an early intervention strategy for Arkansas' poverty children. The core rationale behind the implementation of the Arkansas Better Chance for School Success Pre-school Program was the belief that it is much easier not to be left behind if you do not start behind. The study assessed the Arkansas Better Chance for School Success Pre-school Program on the impact of sustained benefits on third grade children who previously …

Go to article

Malaria : Quantitative Analysis Of Sporozoite Production And Movement Into Mosquito Salivary Glands, Gabriel W. Garman Jan 2007

Malaria : Quantitative Analysis Of Sporozoite Production And Movement Into Mosquito Salivary Glands, Gabriel W. Garman

Theses and Dissertations

No abstract provided.

Go to article

Supporting Personhood In Dementia: Examining The Impact Of Volition On Function In Everyday Occupations, Christine L. Raber Jan 2007

Supporting Personhood In Dementia: Examining The Impact Of Volition On Function In Everyday Occupations, Christine L. Raber

Theses and Dissertations

Understanding volition and preferences for occupation is a critical underpinning of effective occupational therapy services that promote and preserve identity for persons with moderate dementia. Although it has been posited that this population has significant difficulty expressing volition for daily occupations, little research has examined the role of volition in guiding engagement in occupations. This phenomenological study provides an in-depth description and analysis of volition in eight persons with moderate dementia. Guiding questions related to understanding patterns of past life interests, outward demonstration of volition, volitional continuity. and the relationship of the social environment to volition and engagement in daily …

Go to article

Camping In The Classroom: Ridiculous Theatre As Serious Drama, John Kenneth Deboer Jan 2007

Camping In The Classroom: Ridiculous Theatre As Serious Drama, John Kenneth Deboer

Theses and Dissertations

My first semester pursuing my MFA in Voice and Speech Pedagogy I vocal-coached an openly gay student playing a straight character who would mask his sexual identity in such a manner that his performance became stiff and uninteresting. Rather than using his personal identity as an asset in the pursuit of a successful performance, his chosen vocal tactics removed any sense of theatricality from his performance. I confronted the student and suggested such extreme vocal suppression diminished the quality of his overall performance. He replied, "So you want me to get the gay out."His use of the phrase, "get the …

Go to article

Electrospun Blends Of Polydioxanone And Fibrinogen For Urological Applications, Joshua Ford Grant Jan 2007

Electrospun Blends Of Polydioxanone And Fibrinogen For Urological Applications, Joshua Ford Grant

Theses and Dissertations

The need for tissue and organ replacements cannot be satisfied by autograft and allografts alone. The purpose of this study was to investigate the feasibility of electrospinning a blend of polydioxanone and fibrinogen to produce an engineered tissue scaffold. Fiber diameter and pore size of blends were characterized, as well as mechanical strength. Cell proliferation assays for 1 and 7 day cultures were preformed, and a histological evaluation was performed to determine how favorable the various blends were to cell infiltration and proliferation. Some ratios of blends were identified that contained both acceptable mechanical properties and properties that facilitated cell …

Go to article

Design Synthesis And Evaluation Of Diterpenones As Potent Chemopreventive Agents For Aflatoxin B1 Induced Carcinogenesis In Human Liver Cells, Miguel Angel Zuniga Jan 2007

Design Synthesis And Evaluation Of Diterpenones As Potent Chemopreventive Agents For Aflatoxin B1 Induced Carcinogenesis In Human Liver Cells, Miguel Angel Zuniga

Theses and Dissertations

DESIGN, SYNTHESIS, AND EVALUATION OF DITERPENONES AS POTENT CHEMOPREVENTIVE AGENTS FOR AFB1 INDUCED CARCINOGENISIS IN HUMAN LIVER CELLS By Miguel A. Zuniga, Ph.D. A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University. Major Director: Qibing Zhou, Ph.D Assistant Professor Department of Chemistry Terpene quinone methides (TPQMs) have been isolated from a variety of plants and show broad activities against bacteria, fungi, and cancerous cell lines. The biological activity has been attributed to the reactive electrophilic QM moiety, this structural feature has long been recognized as an intermediate in organic …

Go to article

The Influence Of Parental Monitoring And Peer Deviance On Substance Use Among Middle School Students, Sally Ann Mays Jan 2007

The Influence Of Parental Monitoring And Peer Deviance On Substance Use Among Middle School Students, Sally Ann Mays

Theses and Dissertations

Substance use is a significant problem among middle school students in the United States. Research indicates that the early use of substances increases the likelihood of negative outcomes including long-term use and abuse. Both parenting and peer variables exert strong influences on children's decisions to use or abstain from substances. As children age, peers begin to exert a stronger influence, but parenting practices can significantly reduce peers' harmful influences. In this study, three waves of data (collected at the end of 6th grade, and the beginning and end of 7th grade) from a large multi-site study were used to examine …

Go to article

Sodium Hypochlorite's Effect On Nickel-Titanium Rotary Instruments And Its Effect On Resistance To Fracture, Michael Shane Smith Jan 2007

Sodium Hypochlorite's Effect On Nickel-Titanium Rotary Instruments And Its Effect On Resistance To Fracture, Michael Shane Smith

Theses and Dissertations

The purpose of this study was to examine the effect of partial and total immersion in sodium hypochlorite on nickel-titanium rotary files and to determine whether resistance to fracture was influenced by the immersion time. One hundred K3™ and 100 ProFile® rotary files were either partially or totally immersed in 5.25% sodium hypochlorite for zero, one, five, thirty, or sixty minutes. After immersion, files were subjected to cyclic fatigue testing. Time to fracture was recorded and analyzed by a two-way ANOVA. Tukey's honest significant difference was used to identify any differences in immersion times. Within all ProFile groups and partial …

Go to article

The Ksga Methyltransferase: Characterization Of A Universally Conserved Protein Involved In Robosome Biogenesis, Heather Colleen O'Farrell Jan 2007

The Ksga Methyltransferase: Characterization Of A Universally Conserved Protein Involved In Robosome Biogenesis, Heather Colleen O'Farrell

Theses and Dissertations

The KsgA enzymes comprise an ancient family of methyltransferases that are intimately involved in ribosome biogenesis. Ribosome biogenesis is a complicated process, involving numerous cleavage, base modification and assembly steps. All ribosomes share the same general architecture, with small and large subunits made up of roughly similar rRNA species and a variety of ribosomal proteins. However, the fundamental assembly process differs significantly between eukaryotes and eubacteria, not only in distribution and mechanism of modifications but also in organization of assembly steps. Despite these differences, members of the KsgA/Dim1 methyltransferase family and their resultant modification of small-subunit rRNA are found throughout …

Go to article

Immunohistochemical Study Of Phenotypes Of Dendritic Cells In Dental Pulps From Non-Carious And Carious Teeth, Melissa A. Harmon Jan 2007

Immunohistochemical Study Of Phenotypes Of Dendritic Cells In Dental Pulps From Non-Carious And Carious Teeth, Melissa A. Harmon

Theses and Dissertations

Mature dendritic cells (DCs) in inflamed tissues may promote inflammation but the status of DCs in pulpitis is not known. We hypothesized that DC maturation would correlate with carious lesion depth and that CD4+ cells would be found in association with mature DCs. Pulps were collected from teeth exhibiting: (I) no caries (n=9), (II) shallow dentinal caries (n=5), and (III) deep caries (n=9). Pulpal tissues were cryo-sectioned and positive cells were examined with immunohistochemistry, Mature DCs (CD83+) were almost exclusively restricted to pulps from deep caries. Furthermore, CD209+ DCs in deep caries were elevated over other groups and CD209+ cells …

Go to article

Pedagogical Fusion, David Maurice White Jan 2007

Pedagogical Fusion, David Maurice White

Theses and Dissertations

During the five semesters that I have been at VCU I have learned a great deal from the courses that I have been enrolled in but I have learned the most through my experiences as a Teaching Assistant. These experiences have been so valuable because of the wide range of subject areas in which I have been involved and the diverse instructors that I have assisted. Although I hesitate to use the word "problem" I feel that there is a tendency in teacher training for a student to latch onto one professor and model their teaching practices after that one …

Go to article

An Exploration Of The Influence Of Race And Gender On Sexual Beliefs And Attitudes Of Adolescents, Kristine Marie Vandenberg Jan 2007

An Exploration Of The Influence Of Race And Gender On Sexual Beliefs And Attitudes Of Adolescents, Kristine Marie Vandenberg

Theses and Dissertations

This study explores factors that influence the sexual attitudes and behaviors of adolescents specifically through an examination of social constructs that measure sexual beliefs and attitudes of adolescents and the relationships between race and gender and sexual beliefs and attitudes. As the U.S. has maintained one of the highest rates of unplanned teen pregnancy and births among industrialized nations, schools and community groups have struggled to combat teen pregnancy and worked toward designing effective prevention programs. Through an emphasis either on abstinence or safe sex practices, these programs strive to influence adolescents' sexual behavior. However, studies and reports reveal a …

Go to article

Structures And Reactivities Of Ionized And Metal Cation-Containing Acetylene Clusters, Paul O. Momoh Jan 2007

Structures And Reactivities Of Ionized And Metal Cation-Containing Acetylene Clusters, Paul O. Momoh

Theses and Dissertations

In this dissertation, the ion mobility technique is used to determine the structures of small acetylene cluster ions, (C2H2)1-3+, mass-selected from the largest ever reported ionized acetylene clusters. The technique is also used to characterize the reaction of acetylene clusters with water in an effort to elucidate thermochemistry and kinetics of some interesting ion-molecule reactions suspected to occur in interstellar clouds and other interplanetary bodies.A combination of ion mobility measurements, collision induced dissociation (CID), and theoretical calculations are used to provide the most conclusive evidence for the frequently hypothesized trimerization of ionized acetylene to form the benzene ion. The results …

Go to article

Induction Of Heme Oxygenase By A Carbon Monoxide-Releasing Molecule, Robert Andrew Kulina Jan 2007

Induction Of Heme Oxygenase By A Carbon Monoxide-Releasing Molecule, Robert Andrew Kulina

Theses and Dissertations

We have recently demonstrated that heme oxygenase is expressed in both healing wounds and in pressure ulcers. Heme oxygenase has been shown to have important cytoprotective functions in myocardial ischemia-reperfusion injury and organ allograft survival. The cytoprotective effects of heme oxygenase are multifactorial. Besides reducing levels of pro-oxidant heme, heme oxygenase products (bilirubin, carbon monoxide, and iron) have been demonstrated to possess anti-oxidant, anti-inflammatory, anti-apoptotic, and anti-proliferative properties. These properties make heme oxygenase an attractive therapeutic target for the prevention and treatment of chronic wounds. The purpose of this study was two-fold: evaluate the effects of carbon monoxide (CO) on …

Go to article

Divergent Roles Of Pi3k And Akt In Rapamycin-Induced Cardioprotection Against Ischemia-Reperfusion Injury, Shivani Kirit Desai Jan 2007

Divergent Roles Of Pi3k And Akt In Rapamycin-Induced Cardioprotection Against Ischemia-Reperfusion Injury, Shivani Kirit Desai

Theses and Dissertations

Coronary heart disease (CHD) is one of the leading causes of death every year with nearly three-fourths of all deaths caused by the disease. The challenge scientists are facing today is discovering new drugs to protect the heart against cellular damage caused by ischemia-reperfusion injury (I-R injury). Rapamycin is one such drug that has been shown to protect the heart against ischemia-induced cellular injury. Rapamycin(sirolimus) inhibits protein synthesis through inhibition of the mammalian target ofrapamycin (mTOR). This property of rapamycin has led to its current clinical applications in drug-eluting stents and in immunosuppresive treatment to organ transplant patients. The mechanism …

Go to article

Children With Special Needs Oral Health Quality Of Life Survey, Kristin Elizabeth Nelson Jan 2007

Children With Special Needs Oral Health Quality Of Life Survey, Kristin Elizabeth Nelson

Theses and Dissertations

Purpose: The purpose of this study was to asses the oral health quality of life of children with special health care needs. This study examined the effects of oral health conditions on general well-being and family life of these children. A secondary aim of the study was to investigate correlations between specific health care conditions, gender, and age of these children and their global ratings of oral health and well-being.Methods: This study was a cross-sectional design with subjects who are members of the Virginia Care Connection for Children program, based at Virginia Commonwealth University. The oral health quality of life …

Go to article

The Role Of Inhibitory Interneurons In A Model Od Developmental Epilepsy, Patrick James Wolfgang Jan 2007

The Role Of Inhibitory Interneurons In A Model Od Developmental Epilepsy, Patrick James Wolfgang

Theses and Dissertations

Epilepsy, defined by recurrent seizures, is the one of the most prevalent neurological disorders worldwide (World Health Organization 2007). While many forms of epilepsy are well-controlled by anti-epileptogenic medications, a significant portion of patients have intractable, i.e. untreatable, seizures. The etiology of these seizures is varied, but a significant cause, particularly for patients with intractable epilepsy is developmental malformation. In these cases, an error or interruption during the development of the neocortex produces a structural alteration. Such patients may have other neurological problems, but seizures are the most common symptom. The neuronal mechanisms that link malformation and cortical hyperexcitability are …

Go to article

Initial Studies On A Novel Target-Promoted Dna Alkylation System, Ting Xu Jan 2007

Initial Studies On A Novel Target-Promoted Dna Alkylation System, Ting Xu

Theses and Dissertations

A novel target-promoted DNA alkylation system was designed, which consists of a DNA intercalating/alkylating quinone methide (QM) precursor, a removable amine linker, and a sequence-specific delivery. The QM in this system was regenerated by eliminating the amino linker promoted by the hydrophobic interaction between the target DNA and the intercalating QM precursor. Three alkylation model systems (methoxyl polycyclic system, intramolecular hydrogen bonding system and biaryl system) were proposed and synthesized. The potential DNA QM alkylation was investigated by deoxyadenosine (dA) and deoxyguanosine (dG) alkylation with the biaryl system. Only one deoxynucleoside adduct was observed when dA or dG reacted with …

Go to article

Design Of An Electrospun Type Ii Collagen Scaffold For Articular Cartilage Tissue Engineering, Catherine Pemble Barnes Jan 2007

Design Of An Electrospun Type Ii Collagen Scaffold For Articular Cartilage Tissue Engineering, Catherine Pemble Barnes

Theses and Dissertations

Traumatic defects in articular cartilage can lead to joint disease and disability including osteoarthritis. Because cartilage is unable to regenerate when injured, the field of tissue engineering holds promise in restoring functional tissue. In this research, type II collagen was electrospun, cross-linked, and tested as scaffolds for supporting chondrocyte growth. The mechanical, biochemical, and histological characteristics of the engineered tissue were assessed as a function of the electrospinning solution concentration (i.e. scaffold fiber diameter and pore properties) and as a function of the time in culture (evaluated at 2, 4, and 6 weeks). Fiber diameter had a linear relationship with …

Go to article

Constraints On Breastfeeding Choices For Low Income Mothers, Carol Grace Hurst Jan 2007

Constraints On Breastfeeding Choices For Low Income Mothers, Carol Grace Hurst

Theses and Dissertations

The choice to breastfeed a baby is a woman's concern with impact reaching beyond each individual mother and child to longer term health and mental health outcomes for society. The U.S. government has made increasing breastfeeding rates one of its major public health goals for 2010. Breastfeeding is a health disparity issue with mothers who are poor, young, less educated or Black less likely to breastfeed. This project examined impacts of sexual perceptions of breastfeeding, social support, and work on breastfeeding choices made by a sample of low income mothers. A cross-sectional survey design was employed to examine potential barriers …

Go to article

Oral Health Services In A Medical Setting, Robert William Mansman Ii Jan 2007

Oral Health Services In A Medical Setting, Robert William Mansman Ii

Theses and Dissertations

Purpose: The purpose of this study is to examine the baseline oral health status of infants and the level of their caregiver's oral health knowledge for families who received preventive oral health services in a medical setting. Methods: Using a prospective cohort study, children 0-3 years of age received an oral health screening, risk assessment, caregiver education, and a fluoride varnish treatment in an ambulatory pediatric medical clinic. A 16-item oral health knowledge and socio-demographic questionnaire was delivered to the caregiver of child. This questionnaire included knowledge, behavior and opinion items on risk factors for dental diseases, care of child's …

Go to article

In Search Of The Ooey Gooey Good, Lauren Ashley Clay Jan 2007

In Search Of The Ooey Gooey Good, Lauren Ashley Clay

Theses and Dissertations

This thesis explores ideas of everydayness, the mundane, and the repetitive emptiness of consumer culture. It looks at the malaise that plagues everyday life and examines several attempts throughout history to break from its grips which revolve around a search for a more ideal state. This research includes utopias of modernism, the transcendental, the communal living of Shakers and Early Christians, ascetic monks and The Desert Fathers. These ideas have shaped my studio practice as I construct installations based on worlds which allude to the eternal, the otherworldly, and the fragility of our physical world when compared to more eternal …

Go to article

Study Of Covalent And Non-Covalent Interactions In Ternary Systems Involving: Metal/Dna-Rna/Protein, Where Metal = Platinum(Ii), Palladium(Ii), Anzellotti I. Atilio Jan 2007

Study Of Covalent And Non-Covalent Interactions In Ternary Systems Involving: Metal/Dna-Rna/Protein, Where Metal = Platinum(Ii), Palladium(Ii), Anzellotti I. Atilio

Theses and Dissertations

Ternary systems comprising DNA/RNA, proteins and one (or more) metal ion are generating increased interest due to its biological relevance. The knowledge gained from the study of these systems could provide important clues regarding the precise mechanism for transcription factors, repair proteins and metal complexes with anti-tumoral/anti-viral activities.The interactions occurring among the components of these ternary systems can be broadly grouped into covalent and non-covalent. The first kind of interactions can lead to the irreversible transformation of the components in the system, while the second is thought to be reversible leading to transient states and fluxionality. Both kinds of interaction …

Go to article

Observational Intelligence: An Overview Of Computational Actual Entities And Their Use As Agents Of Artificial Intelligence, Brandon Scot Saunders Jan 2007

Observational Intelligence: An Overview Of Computational Actual Entities And Their Use As Agents Of Artificial Intelligence, Brandon Scot Saunders

Theses and Dissertations

This thesis' focus is on the use of Alfred North Whitehead's concept of Actual Entities as a computational tool for computer science and the introduction of a novel usage of Actual Entities as learning agents. Actual Entities are vector based agents that interact within their environment through a process called prehension. It is the combined effect of multiple Actual Entities working within a Colony of Prehending Entities that produces emergent, intelligent behavior. It is not always the case that prehension functions for desired behavior are known beforehand and frequently the functions are too complex to construct by hand. Through the …

Go to article

The Role Of Sphingosine Kinase 2 In Cell Growth And Apoptosis, Heidi M. Sankala Jan 2007

The Role Of Sphingosine Kinase 2 In Cell Growth And Apoptosis, Heidi M. Sankala

Theses and Dissertations

Two isoforms of sphingosine kinase (SphK) catalyze the formation of sphingosine-1-phosphate (SIP). Whereas, SphKl stimulates cell growth and survival, it was found that when overexpressed in mouse NIH 3T3 fibroblasts SphK2 enhances caspase-dependent apoptosis in response to serum deprivation, independently of S1P receptors. Sequence analysis revealed that SphK2 contains a 9 amino acid motif similar to that present in BH3-only proteins. Studies showed that the BH3-only domain, catalytic activity, endoplasmic reticulum (ER) stress, and uptake of calcium by the mitochondria may all contribute to the apoptotic effects of overexpressed SphK2 in NIH 3T3 cells. Further studies in human carcinoma cells …

Go to article

First Prev Next Last