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2018

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An Approach To Improve Single Photon Detectors For Highly Sensitive Applications, Ahmed Chyad Kadhim Dec 2018

An Approach To Improve Single Photon Detectors For Highly Sensitive Applications, Ahmed Chyad Kadhim

Theses and Dissertations

The problem of detecting a single photon is receiving considerable attention with the development of new single photon detectors in biophotonics, stressed free-space optical communication, low probability of intercept (LPI) optical communication, quantum communication, and remote sensing. The theoretical modeling of the waveforms of the single photon detector output produced in particular systems will expedite the search for and analysis of detected signals. Since SNSPDs require cooling to very low temperature, 4K, and PMTs work on the visible wavelength, current photon detection focus on research developing SPADs and using InGaAs/InP materials. However, SPADs can work over the infrared range of …

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Floxed-Cassette Allelic Exchange Mutagenesis Enables Markerless Gene Deletion In Chlamydia Trachomatis And Can Reverse Cassette-Induced Polar Effects, Gabrielle Keb, Robert Hayman, Kenneth A. Fields Dec 2018

Floxed-Cassette Allelic Exchange Mutagenesis Enables Markerless Gene Deletion In Chlamydia Trachomatis And Can Reverse Cassette-Induced Polar Effects, Gabrielle Keb, Robert Hayman, Kenneth A. Fields

Microbiology, Immunology, and Molecular Genetics Faculty Publications

As obligate intracellular bacteria, Chlamydia spp. have evolved numerous, likely intricate, mechanisms to create and maintain a privileged intracellular niche. Recent progress in elucidating and characterizing these processes has been bolstered by the development of techniques enabling basic genetic tractability. Florescence-reported allelic exchange mutagenesis (FRAEM) couples chromosomal gene deletion with the insertion of a selection cassette encoding antibiotic resistance and green fluorescent protein (GFP). Similar to other bacteria, many chlamydial genes exist within polycistronic operons, raising the possibility of polar effects mediated by insertion cassettes. Indeed, FRAEM-mediated deletion of Chlamydia trachomatis tmeA negatively impacts the expression of tmeB. We …

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Empirical Research On The Evaluation Model And Method Of Sustainability Of The Open Source Ecosystem, Zhifang Liao, Libing Deng, Xiaoping Fan, Yan Zhang, Hui Liu, Xiaofei Qi, Yun Zhou Dec 2018

Empirical Research On The Evaluation Model And Method Of Sustainability Of The Open Source Ecosystem, Zhifang Liao, Libing Deng, Xiaoping Fan, Yan Zhang, Hui Liu, Xiaofei Qi, Yun Zhou

College of Natural and Applied Sciences

The development of open source brings new thinking and production modes to software engineering and computer science, and establishes a software development method and ecological environment in which groups participate. Regardless of investors, developers, participants, and managers, they are most concerned about whether the Open Source Ecosystem can be sustainable to ensure that the ecosystem they choose will serve users for a long time. Moreover, the most important quality of the software ecosystem is sustainability, and it is also a research area in Symmetry. Therefore, it is significant to assess the sustainability of the Open Source Ecosystem. However, the current …

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Effect Of Reinforcement Selection On Mate Selection Rates Of Gambusia Affinis And Gambusia Holbrooki, Molly Stephens Dec 2018

Effect Of Reinforcement Selection On Mate Selection Rates Of Gambusia Affinis And Gambusia Holbrooki, Molly Stephens

Honors Theses

This study was conducted in order to investigate the effects that reinforcement selection has on non-hybridized and hybridized populations of two separate species of Gambusia (G. affinis and G. holbrooki). In order to examine if organisms from a population that had been previously exposed to hybridization would choose mates so as to not produce species hybrid offspring, 29 trials consisting of 9 different mate preference combinations and 87 individuals were recorded and analyzed. Once mate preference was determined for each female used in each trial, the effect that reproductive isolation had on reinforcement in hybrid zones was analyzed. The results …

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Quality Improvement For The Jeffmd Clinical Experience Program, Chloe Virgil, Emily Romano, Sara Goldstein, Msw, Lsw, Rhea E. Powell, Md, Mph Dec 2018

Quality Improvement For The Jeffmd Clinical Experience Program, Chloe Virgil, Emily Romano, Sara Goldstein, Msw, Lsw, Rhea E. Powell, Md, Mph

Phase 1

Introduction: The JeffMD curriculum at Sidney Kimmel Medical College, which completed its inaugural year in the spring of 2018, aims to prepare future physicians to “thrive in the landscape of modern healthcare.” The curriculum is based upon the knowledge that human health exists interdependently with all aspects of life, including but not limited to social, health care system, behavioral, and biological factors. The JeffMD Clinical Experience Program (CE) is a mandatory, experiential, value-added component of the curriculum. Through the CE course, which spans the 21-month preclinical period, students work with a Community Health Worker to screen patients for social …

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A Comparison Of Screening, Prevention, And Management For Hepatitis B Patients Between The Us And Chinese Healthcare Systems, Thomas Chen, James D. Plumb, Md Dec 2018

A Comparison Of Screening, Prevention, And Management For Hepatitis B Patients Between The Us And Chinese Healthcare Systems, Thomas Chen, James D. Plumb, Md

Phase 1

Introduction: Hepatitis B (HBV) is a complex disease entity with potentially serious outcomes, including developing hepatocellular carcinoma (HCC). HBV is estimated to be responsible for about 50-80% of HCC cases worldwide, and 75-95% of HCC cases in HBV endemic regions.1 HBV and HCC are great concerns especially in East Asian countries like China. In China, HCC ranks as the 2nd most common cancer and 2nd in cancer mortality, both behind only lung cancer.1 China is considered an endemic HBV region, with about 100-150 million people infected. In comparison, only an estimated 550,000-2 million people are chronically …

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High-Energy Laser Weapons: Overpromising Readiness, Ash Rossiter Dec 2018

High-Energy Laser Weapons: Overpromising Readiness, Ash Rossiter

The US Army War College Quarterly: Parameters

No abstract provided.

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Conformable Derivative Operator In Modelling Neuronal Dynamics, Mehmet Yavuz, Burcu Yaşkıran Dec 2018

Conformable Derivative Operator In Modelling Neuronal Dynamics, Mehmet Yavuz, Burcu Yaşkıran

Applications and Applied Mathematics: An International Journal (AAM)

This study presents two new numerical techniques for solving time-fractional one-dimensional cable differential equation (FCE) modeling neuronal dynamics. We have introduced new formulations for the approximate-analytical solution of the FCE by using modified homotopy perturbation method defined with conformable operator (MHPMC) and reduced differential transform method defined with conformable operator (RDTMC), which are derived the solutions for linear-nonlinear fractional PDEs. In order to show the efficiencies of these methods, we have compared the numerical and exact solutions of fractional neuronal dynamics problem. Moreover, we have declared that the proposed models are very accurate and illustrative techniques in determining to approximate-analytical …

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Parameter Estimation And Optimal Control Of The Dynamics Of Transmission Of Tuberculosis With Application To Cameroon, A. Temgoua, Y. Malong, J. Mbang, S. Bowong Dec 2018

Parameter Estimation And Optimal Control Of The Dynamics Of Transmission Of Tuberculosis With Application To Cameroon, A. Temgoua, Y. Malong, J. Mbang, S. Bowong

Applications and Applied Mathematics: An International Journal (AAM)

This paper deals with the problem of parameter estimation and optimal control of a tuberculosis (TB) model with seasonal fluctuations. We first present a uncontrolled TB model with seasonal fluctuations. We present the theoretical analysis of the uncontrolled TB model without seasonal fluctuations. After, we propose a numerical study to estimate the unknown parameters of the TB model with seasonal fluctuations according to demographic and epidemiological data from Cameroon. Simulation results are in good accordance with the seasonal variation of the new active reported cases of TB in Cameroon. Using this TB model with seasonality, the tuberculosis control is formulated …

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Evaluation Of Presage® As A 3d Dose Verification To Ol In Proton Beams, Mitchell Carroll Dec 2018

Evaluation Of Presage® As A 3d Dose Verification To Ol In Proton Beams, Mitchell Carroll

Dissertations and Theses (Open Access)

Radiotherapy techniques have advanced and radiation dose plans have become much more complex over the last decade. This is especially true in proton therapy, which involves extremely steep dose gradients as a result of positioning the Bragg peak to cover the volumes to be treated. The Bragg peak can be shifted significantly in the patient as a result of nonuniformities in the tissue composition in its path, which can result in treatment complications. Some traditional dose verification tools used in proton beam commissioning and treatment plan verification are film, TLD, and ionization chambers. Such 0D and 2D dosimeters are incapable …

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High-Frequency Temperature Variability Mirrors Fixed Differences In Thermal Limits Of The Massive Coral Porites Lobata, Daniel J. Barshis, Charles Birkeland, Robert J. Toonen, Ruth D. Gates, Jonathon H. Stillman Dec 2018

High-Frequency Temperature Variability Mirrors Fixed Differences In Thermal Limits Of The Massive Coral Porites Lobata, Daniel J. Barshis, Charles Birkeland, Robert J. Toonen, Ruth D. Gates, Jonathon H. Stillman

Biological Sciences Faculty Publications

Spatial heterogeneity in environmental characteristics can drive adaptive differentiation when contrasting environments exert divergent selection pressures. This environmental and genetic heterogeneity can substantially influence population and community resilience to disturbance events. Here, we investigated corals from the highly variable back-reef habitats of Ofu Island in American Samoa that thrive in thermal conditions known to elicit widespread bleaching and mortality elsewhere. To investigate the relative importance of acclimation versus site of origin in shaping previously observed differences in coral tolerance limits at Ofu Island, specimens of the common Indo-Pacific coral Porites lobata from locations with differing levels of thermal variability were …

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Vitality Of Water/Vitalidad Del Agua: Our Sacred Connection To Water And How We Can Interpret The Importance Of Water Through Artistic Inquiry, Jenifer Fogarty Dec 2018

Vitality Of Water/Vitalidad Del Agua: Our Sacred Connection To Water And How We Can Interpret The Importance Of Water Through Artistic Inquiry, Jenifer Fogarty

Master's Theses

Water has appeared in the work and study of artists for centuries. There are countless aspects of water to be explored, from the sheer physical qualities of water to the spiritual, political, and practical associations with water. Water is what gives us life, and yet the vitality of this precious resource has been threatened over time. This exploration highlights important aspects of the study of water through art-making. My exploration began in the studio while making my own work. I sought to create a multi-sensory environment where viewers could participate and be immersed in the work itself. The site-specific installation …

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Postpartum Depression In The News Media, Lauren Michelle Mcdonald Dec 2018

Postpartum Depression In The News Media, Lauren Michelle Mcdonald

Master's Theses

The current study analyzed the relationship between gender constructs and the construction of illness in the news media. Drawing on Entman’s (1993) framing analysis, the present study assessed if postpartum depression was constructed in the news media differently for men and women. Using LexisNexis, 153 news media articles were collected from major United States news sources between 1994-2016 using keywords such as, postpartum depression and paternal depression. The content analysis indicated that the definition of postpartum depression, the cause of the illness, the moral evaluations and the prescribed treatments were related to gender constructs. Overall, these findings enhance our understanding …

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Patterns Of Authorship In Ecology And Evolution: First, Last, And Corresponding Authorship Vary With Gender And Geography, Charles W. Fox, Josiah P. Ritchey, C. E. Timothy Paine Dec 2018

Patterns Of Authorship In Ecology And Evolution: First, Last, And Corresponding Authorship Vary With Gender And Geography, Charles W. Fox, Josiah P. Ritchey, C. E. Timothy Paine

Entomology Faculty Publications

The position of an author on the byline of a paper affects the inferences readers make about their contributions to the research. We examine gender differences in authorship in the ecology literature using two datasets: submissions to six journals between 2010 and 2015 (regardless of whether they were accepted), and manuscripts published by 151 journals between 2009 and 2015. Women were less likely to be last (i.e., “senior”) authors (averaging ~23% across journals, years, and datasets) and sole authors (~24%), but more likely to be first author (~38%), relative to their overall frequency of authorship (~31%). However, the proportion of …

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Legal Principles And Seminal Legal Cases In Oocyte Donation, Jody L. Madeira, Susan L. Crockin Dec 2018

Legal Principles And Seminal Legal Cases In Oocyte Donation, Jody L. Madeira, Susan L. Crockin

Articles by Maurer Faculty

Oocyte donation has played an increasingly important role in assisted reproductive technologies since the early 1980s. Over the past 30 years, unique legal standards have evolved to address issues in the oocyte donation procedure itself as well as the disputes over issues, such as parentage, that inevitably arise with new technologies, particularly for individuals seeking to build nontraditional families. This essay will explore oocyte donation's legal aspects as well as seminal law concerning the procedure, including statutory law (uniform and model provisions and enacted state laws) and selected judicial opinions concerning surrogacy and parentage, testing of oocyte donors, mix-ups of …

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The Intersection Of Literacy And Digital Literacy: Incorporating Writing Standards With Computer Technology Standards, Grace Mcpherson Dec 2018

The Intersection Of Literacy And Digital Literacy: Incorporating Writing Standards With Computer Technology Standards, Grace Mcpherson

Honors Theses

This project aims to increase access to computer science/computer technology education by providing teachers resources to enable them to teach computer science/computer technology. A survey was taken to discover the interests and needs of teachers in Hamilton County, Tennessee. The project resulted in the creation of several lesson plans that integrate English and computer science through hands-on web development exercises, computational thinking opportunities, and critical thinking.

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Use Of Stereolithographic 3d Printing For Fabrication Of Micro And Millifluidic Devices For Undergraduate Engineering Studies, Cooper Thome Dec 2018

Use Of Stereolithographic 3d Printing For Fabrication Of Micro And Millifluidic Devices For Undergraduate Engineering Studies, Cooper Thome

Honors Theses

Undergraduate STEM student performance is greatly benefited by supplementary, hands-on laboratory experience. Micro and millifluidic devices provide a multitude of opportunities for interactive study of concepts and phenomena encountered in nearly every field of engineering, as well as in chemistry, biology, and other disciplines. Unfortunately, due to the cost and difficulty of standard micro and millifluidic device fabrication methods, many undergraduate students do not have access to these versatile educational tools. Luckily, 3D printing offers an inexpensive and simple solution to this issue. This work aims to demonstrate the capability of stereolithographic (SLA) 3D printing for the fabrication of micro …

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The Grotesque Self: Finding Identity Through The Grotesque In The Works Of Carson Mccullers, Colton Greganti Dec 2018

The Grotesque Self: Finding Identity Through The Grotesque In The Works Of Carson Mccullers, Colton Greganti

Honors Theses

Historically speaking, the South has maintained rigid, male dominated constructions of gender, which have manifested themselves in almost every aspect of the southern individual’s actions, sense of self, and appearance. While much of southern culture has been centered on this rigid identity, the southern gothic literary tradition strays from this stark binary, especially in its depiction of female characters. Through the use of grotesque representations, these characters are able to form a unique identity and deviate from the phallocentric social norms, though it often comes at the cost of social alienation. However, even when tragedies strike these gothic heroines, their …

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Investigation Of Electrolytic Flocculation For Microalga Scenedesmus Sp Using Aluminum And Graphite Electrodes, Shihong Liu, Husam A. Abu Hajar, Guy Riefler, Ben J. Stuart Dec 2018

Investigation Of Electrolytic Flocculation For Microalga Scenedesmus Sp Using Aluminum And Graphite Electrodes, Shihong Liu, Husam A. Abu Hajar, Guy Riefler, Ben J. Stuart

Civil & Environmental Engineering Faculty Publications

Electrolytic flocculation using non-sacrificial electrodes with flocculants added was studied on harvesting Scenedesmus sp. In order to optimize the operating conditions of the electrolytic flocculation process and to quantify the amount of flocculants added, aluminum electrodes were first used in the process. It was found that under optimal conditions, the microalgae removal efficiency using aluminum electrodes could reach 98.5%, while 34.2 mg L-1 of aluminum ions were released during the process. Different metal electrodes were also studied, but high microalgae removal efficiency was witnessed only using aluminum electrodes, indicating the influence of the aluminum ion in flocculation. When non-sacrificial …

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Process-Property-Microstructure Relationships In Laser-Powder Bed Fusion Of 420 Stainless Steel., Subrata Deb Nath Dec 2018

Process-Property-Microstructure Relationships In Laser-Powder Bed Fusion Of 420 Stainless Steel., Subrata Deb Nath

Electronic Theses and Dissertations

Laser-powder bed fusion (L-PBF) is an additive manufacturing technique for fabricating metal components with complex design and customized features. However, only a limited number of materials have been widely studied using L-PBF. AISI 420 stainless steel, an alloy with a useful combination of high strength, hardness, and corrosion resistance, is an example of one such material where few L-PBF investigations have emerged to date. In this dissertation, L-PBF experiments were conducted using 420 stainless steel powders to understand the effects of chemical composition, particle size distribution and processing parameters on ensuing physical, mechanical and corrosion properties and microstructure in comparison …

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Characterization Of Microreactor And Analysis Of Carbonyl Compounds In Exhaled Breath., Qi Li Dec 2018

Characterization Of Microreactor And Analysis Of Carbonyl Compounds In Exhaled Breath., Qi Li

Electronic Theses and Dissertations

Analysis of trace volatile organic compounds at parts per billion (ppbv) to parts per trillion (pptv) level has become an important research frontier because of the applicability for environmental monitoring and noninvasive diagnosis of diseases. The methods of preconcentration for detection of trace aldehydes and ketones both in ambient air and human exhaled breath have increased considerably over the last decade. However, the majority of these methods are not efficient. In this dissertation, we have improved an innovative microreactor that is suitable for quantitative analysis of volatile carbonyl compounds (VOCs) in ambient air as well as in human exhaled breath. …

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Coagulation Factor Xiiia: Biochemical Properties Underlying Physiological Function., Boris Anokhin Dec 2018

Coagulation Factor Xiiia: Biochemical Properties Underlying Physiological Function., Boris Anokhin

Electronic Theses and Dissertations

Factor XIIIA (FXIIIA) is a transglutaminase that crosslinks intra- and extracellular protein substrates. The oligomeric state of active FXIIIA remains controversial, and the present work commenced with addressing this issue. The results of size exclusion chromatography and analytical ultracentrifugation confirmed a dimeric state for zymogen and, for the first time, indicated a monomeric state for the active FXIIIA in solution. Comparing sedimentation properties of proteolytically and nonproteolytically activated FXIIIA suggested conformational and functional differences between the two forms. Those differences were further assessed in a series of catalytic activity studies. Kinetic analysis revealed affinity for the glutamine substrate was higher …

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Evaluation Of The Predictive Ability Of A Screening Instrument Used To Diagnose Co-Occurrence Of Anxiety In Children With High-Functioning Autism., Austin Zachary Dec 2018

Evaluation Of The Predictive Ability Of A Screening Instrument Used To Diagnose Co-Occurrence Of Anxiety In Children With High-Functioning Autism., Austin Zachary

Electronic Theses and Dissertations

Anxiety has shown to have a high co-occurrence in children with Autism Spectrum Disorder (ASD), but has been difficult to co-diagnose. This study analyzed the ability of the Screen for Child Anxiety-Related Emotional Disorders (SCARED) to predict positive ASD screenings of the Social Responsiveness Scale (SRS). Parents and children ages 8 to 18 years (N = 100) were screened for anxiety using the SCARED and autism using the SRS. Moderate correlation was found between parent-reported SCARED and positive screening of the SRS (r = .579), with weak correlation found in the child-reported SCARED (r = .105). LASSO regression was conducted …

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Effect Of Grape Components On Periodontal Disease., Juili Subodh Shivde Dec 2018

Effect Of Grape Components On Periodontal Disease., Juili Subodh Shivde

Electronic Theses and Dissertations

Background: Half of the adult American population (47 %) are victims of periodontitis, a chronic inflammatory disease which leads to destruction of the tissues supporting the tooth. Periodontitis is initiated by periodontal pathogens and caused by excessive or prolonged host mediated inflammation. Porphyromonas gingivalisis one important agent implicated in the etiopathogenesis of chronic periodontitis. Pro-inflammatory cytokines induced by periodontal pathogens can cause alveolar bone loss and periodontitis. Bone loss is caused by the imbalance of bone formation and bone resorption. Osteoclasts are major cells that cause bone resorption. Moreover, periodontal inflammation also leads to bone resorption. Grapes are rich …

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Adolescent Sexual And Reproductive Health In The Gambia., Sandhya Lohani Dec 2018

Adolescent Sexual And Reproductive Health In The Gambia., Sandhya Lohani

Electronic Theses and Dissertations

Adolescence is a crucial period in human development. Knowledge and awareness about when to have children, when to have sex, and use of contraceptives impacts the chances of teenage pregnancy and risk of sexually transmitted diseases. The objective of this study is to determine the prevalence and associated risk factors related to age of sexual debut, teenage pregnancy, and use of contraceptives in the Gambia. This study also compares the data with 2014 survey research conducted in the Gambia. The total study population were 50 adolescents aged 13-21 years from Bafuluto and surrounding communities in the Gambia. Among 50 respondents, …

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Student Engagement In Post-Soviet Higher Education: Coping With Academic Quality Problems., J. L. Mettille Dec 2018

Student Engagement In Post-Soviet Higher Education: Coping With Academic Quality Problems., J. L. Mettille

Electronic Theses and Dissertations

This dissertation investigates the experiences of administrators, instructional faculty, and students within a post-Soviet higher education institution in the Kyrgyz Republic using qualitative field research and case study methods. This study identifies the perceived potential of Western benchmarks of effective educational practice to evince positive change in the institution as well as their propriety and relevance in this context. In addition, the propositions underlying the student engagement construct and overarching the benchmarks are evaluated based upon participant responses and classroom observation data. Twenty higher education practitioners and twenty students participated in semi-structured interviews preceding and following seven classroom observations. The …

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Epidermal Growth Factor-Like Ligands Regulate Dimer Selection., Jamie S. Rush Dec 2018

Epidermal Growth Factor-Like Ligands Regulate Dimer Selection., Jamie S. Rush

Electronic Theses and Dissertations

There are thirteen known endogenous EGF-like ligands. We previously reported that Betacellulin (BTC) increases ligand-mediated corneal wound healing more than Epidermal Growth Factor (EGF) [Peterson et al. (2014) IOVS 55(5):2870-80], although the molecular reason for this is unknown. Despite being better at promoting wound healing via enhanced cell migration, BTC has reduced receptor affinity and weaker induction of EGFR phosphorylation. These data indicate that BTC’s response is not due to enhanced affinity or EGFR-kinase activity. Receptor phosphorylation and proximity ligation assays indicate that BTC treatment significantly increases ErbB3 phosphorylation and EGFR:ErbB3 heterodimers. BTC traffics EGFR at a faster rate than …

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Synthesis And Characterization Of Targeted Bar Encapsulated Polylactic-Co-Glycolic Acid Nanoparticles To Inhibit Porphyromonas Gingivalis Biofilm Formation., Ranjith Radha Krishnan Dec 2018

Synthesis And Characterization Of Targeted Bar Encapsulated Polylactic-Co-Glycolic Acid Nanoparticles To Inhibit Porphyromonas Gingivalis Biofilm Formation., Ranjith Radha Krishnan

Electronic Theses and Dissertations

Periodontal disease is one of the most prevalent infectious diseases worldwide. Between 30-50% of the global adult population suffers from periodontal disease. Some form of periodontitis is present in 46% of American adults, corresponding to annual expenditures in excess of 14 billion dollars for treatment and prevention. Current treatments for periodontal diseases involve mechanical removal of plaque, correction of risk factors, gingival surgery and/or antibiotic therapy. To our knowledge there is no effective therapeutic approach that aims to limit pathogen colonization of the oral biofilm or re-colonization after treatment. Interaction of the pathogen Porphyromonas gingivalis with oral streptococci is critical …

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Particulate Hexavalent Chromium Does Not Induce Centrosome Amplification In Sperm Whale And Bowhead Whale Cells., Jennifer Haruka Toyoda Dec 2018

Particulate Hexavalent Chromium Does Not Induce Centrosome Amplification In Sperm Whale And Bowhead Whale Cells., Jennifer Haruka Toyoda

Electronic Theses and Dissertations

Hexavalent chromium [Cr(VI)] is a widespread environmental and occupational carcinogen. The mechanism of carcinogenesis remains poorly understood, but chromosome instability (CIN) is the dominant theory. How numerical CIN arises is unclear, but it correlates with centrosome amplification. Both phenotypes are hallmarks of cancers, early events in carcinogenesis, and have been shown to occur after Cr(VI) exposure to human skin and lung fibroblasts. In this study, we investigate numerical CIN and centrosome amplification in whale cells. Whales are our closest marine relatives, have long lifespans, and are exposed to environmental Cr(VI). Importantly, they have low cancer rates and cell culture studies …

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Structure Of Native Lens Connexin 46/50 Intercellular Channels By Cryo-Em, Janette B. Myers, Bassam G. Haddad, Susan E. O'Neill, Dror S. Chorev, Craig C. Yashioka, Carol V. Robinson, Daniel M. Zuckerman, Steve L. Reichow Dec 2018

Structure Of Native Lens Connexin 46/50 Intercellular Channels By Cryo-Em, Janette B. Myers, Bassam G. Haddad, Susan E. O'Neill, Dror S. Chorev, Craig C. Yashioka, Carol V. Robinson, Daniel M. Zuckerman, Steve L. Reichow

Chemistry Faculty Publications and Presentations

Gap junctions establish direct pathways for cell-to-cell communication through the assembly of twelve connexin subunits that form intercellular channels connecting neighbouring cells. Co-assembly of different connexin isoforms produces channels with unique properties and enables communication across cell types. Here we used single-particle cryo-electron microscopy to investigate the structural basis of connexin co-assembly in native lens gap junction channels composed of connexin 46 and connexin 50 (Cx46/50). We provide the first comparative analysis to connexin 26 (Cx26), which—together with computational studies—elucidates key energetic features governing gap junction permselectivity. Cx46/50 adopts an open-state conformation that is distinct from the Cx26 crystal structure, …

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