Boston University Theses & Dissertations

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This is the master collection of contemporary BU theses and dissertations. We plan to consolidate school- and college-specific collections into this one, and add school- and college-specific metadata to enable users to browse appropriately.

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Sample PROQUEST SWORD Deposit with Embargo
(2015) Student, Graduate Middle; Carroll, Test C; Simon, User R
Description for Sample Dissertation.
Sample PROQUEST SWORD Deposit with Embargo
(2015) Student, Graduate Middle; Carroll, Test C; Simon, User R
Description for Sample Dissertation.
Comparison of language and somatic experiences between reports of trauma and trauma-related dreams & personality features of trauma-exposed persons reporting trauma-related dreams
(2024) Hickey, Kimberly Lynn; Trinkaus-Randall, Vickery; Pace-Schott, Edward
INTRODUCTION: (Study A) Trauma-Related Nightmares (TRNs) are a core feature of Post- Traumatic Stress Disorder (PTSD). We explored linguistic and somatic-experience differences between self-reports of trauma and those of nightmares related to the trauma. (Study B) Neurotic personality features are associated with many psychological disorders, including PTSD. Based on this relationship, we explored whether neuroticism predicts the rate of nightmares and bad dreams as well as the number of replicative nightmares (TRNs similar or exactly like their traumatic experience), above and beyond PTSD severity. METHODS: (Study A) Seventeen participants with varying severity of PTSD symptoms reporting recurring TRNs (mean age 27.47 years, SD = 10.33, 14 females) recalled a traumatic experience and nightmares related to that trauma. Trauma reports were written by participants, while nightmare reports were transcribed from audio recordings made as they were recalled following nightmares. Following both types of reports, participants indicated co-occurring somatic experiences by choosing from a list of 51 selections. Choices were later grouped into cardiovascular, respiratory, interoceptive, and tension categories. Linguistic content was measured using the Linguistic Inquiry and Word Count (LIWC) program and positive emotion, negative emotion, and somatosensory category words were totaled. Since trauma reports had significantly higher word counts than TRNs (p=0.0495), LIWC categories were normalized for total word count. Total and symptom- cluster severities of PTSD were assessed using the PTSD Checklist for DSM-5 (PCL-5). Wilcoxon Signed-Rank Tests and Spearman Correlations were used for statistical analysis, as Shapiro-Wilk tests showed that data were non-normally distributed. (Study B) 126 participants who had experienced a traumatic event within the past two years were recruited (mean age 24.13 years, SD = 4.994, 69% female) and, for an average of 14.89 nights, completed a dream questionnaire on which occurrence of nightmares (causing awakening) and bad dreams were reported and ranked based on their similarity to their recent traumatic experience. PTSD symptoms were assessed using the PCL-5 and personality features such as neuroticism were measured using the NEO Personality Inventory Revised (NEO PI-R), a questionnaire based on the Five Factor Model of personality. The combined number of nightmares and bad dreams was divided by the total number of nights reported and expressed as a rate, while a replicative nightmare count was generated by summing “similar to traumatic experience” and “exactly like traumatic experience” ratings. Hierarchical regressions were used to determine whether neuroticism predicted the rate of nightmare and bad dreams as well as the number of replicative nightmares above and beyond PTSD severity. Pearson correlations were used to check for relationships between variables and possible collinearity. RESULTS: (Study A) There were significantly more somatic experiences of interoception (p=0.0084) and tension (p=0.024) in trauma vs nightmare reports. The intrusion cluster of the PCL-5 was associated with cardiovascular (rho=0.592, p=0.0156) and respiratory (rho=0.619, p=0.0109) experiences in trauma reports, and interoception (rho=0.718, p=0.0033) and tension (rho=0.556, p=0.0224) experiences in nightmare reports. (Study B) In two hierarchical regression models, neuroticism predicted neither nightmare and bad dream rate nor number of replicative nightmares over and above total or PTSD symptom cluster severity (p=0.596; p=0.886). Collinearity checks did demonstrate a moderate positive relationship between these variables (r=0.317, p<0.001). CONCLUSION: (Study A) More somatic experiences of interoception and tension were recalled from traumas than TRNs. Because the brain is deafferented from sensory input during dreaming, we expected, but did not find, state differences in other somatic experiences. Word categories in narratives also did not show state differences. Only the intrusion symptoms of PTSD predicted bodily sensations in trauma as well as TRN reports. (Study B) We found that neuroticism did not predict either nightmare and bad dream rate or the number of replicative nightmares above and beyond PTSD severity, when taking demographic factors into account. The positive correlation between PTSD and neuroticism could explain this lack of significance. SUPPORT: R21MH128619
The world “In Search of its Soul”: UNESCO, America, and the struggle to build a postcolonial world
(2016) Olson, David; Keylor, William R.
This dissertation traces the international, intellectual, and institutional history of the United Nations Educational, Scientific, and Cultural Organization (UNESCO). This organization became the intellectual branch of the United Nations and was able to mobilize intellectual resources from around the world. Historians, educators, economists, and communications theorists used the organization’s conferences, roundtables, and meetings to forge transnational networks. American and European statesmen exploited these networks to encourage postwar peace and promote their own visions of international society. Third World diplomats and intellectuals embraced the organization but campaigned against its Eurocentric priorities. They pushed it to focus on discrediting the set of ideas and assumptions that underpinned the imperial world order. American diplomats and intellectuals championed UNESCO’s anticolonial agenda for decades and assisted such global campaigns as the fight against illiteracy, the preservation of ancient monuments, and the transfer of communications technology. By the 1970s, however, intellectual disagreements about the international economic system sparked a war of ideas and instigated a diplomatic crisis that led to American withdrawal from the organization. The decline of European imperialism and the rise of the Third World led to decades of economic, diplomatic, and military tension. This dissertation concludes that this sea change in world history also led to profound confrontation in the international realm of information and ideas. UNESCO was not the only forum devoted to the international exchange of information and ideas. But its authority as the intellectual arm of the United Nations made it one of the major battlegrounds in the struggle to create a postcolonial world.
Digital music consumption and social capital shifts within the Cape Breton diaspora in Boston
(2015) Berman, Amanda Elaine Daly; Heimarck, Brita R.
While ethnomusicological scholarship has begun to address Internet studies, the field has yet to amply consider digital diaspora theory. Arguing that the increasing digital aspect of social capital – defined as “the benefits individuals derive from their social relationships and interactions” (Ellison, Steinfeld, and Lampe 2010, 873) -- affects social, cultural, and musical capital in diasporic community groups, I discuss the pivotal role that social media, videosharing sites, and other Internet platforms play in connecting diasporic communities. I develop a hybrid ethnographic fieldwork model for examining contemporary diasporas’ music consumption and production that builds upon Putnam’s (2000) work on social capital, Song’s (2009) analysis of virtual communities, Brinkerhoff’s (2009) conceptualization of digital diaspora, Turkle’s (2011) fieldwork on technology’s impact on social interaction, Sparling’s (2006) conception of cultural capital in Gaelic Cape Breton, and O’Hara and Brown’s (2006) examination of music consumption. To address the high value of music production and consumption in Cape Breton culture, I introduce the concept of musical capital. I define this as arts currency, both tangible and intangible, which can be procured, acquired, or shared, as a more specific way to discuss the shifts in participation and consumption documented in my fieldwork in 2014-15, conducted both online and at the Canadian-American Club in Watertown, Massachusetts. Forms of musical capital analyzed include Skype music lessons, songs of diasporic longing, fiddle sessions, online videos, and in-person performances. I conclude that the online availability of one’s culture has long-range effects for community participation by non-musicians. While artists still gather in person to practice and perform, the greater diasporic community can now interact with other members online and virtually experience their culture, though the personal social capital benefits are not equal to in-person interactions. These changes reflect a larger social capital shift within contemporary American society and acknowledge the impact of the increased use of, and reliance upon, Internet platforms as a means for creating, consuming, and disseminating musical and cultural capital.
Quantitative studies of mycobacterial single cell dynamics using a synthetic gene oscillator
(2014) Yu, Wen-Han; Galagan, James E.
The gene regulatory interaction network of Mycobacterium tuberculosis (Mtb) has been mostly reconstructed, resulting in a huge step towards revealing complicated interconnections between the network and cellular responses. Nevertheless, the temporal dynamics of gene expression in the regulatory network still remain unclear. Such information importantly provides further understandings in cellular behaviors underlying the system in the presence of external stresses such as those from the host immune system and drug treatments. Here I applied an engineering-based approach to the new context of studying the Mtb temporal dynamical system by adding a synthetic perturbation system. To do so, I developed the first synthetic gene oscillator functioning as a circadian clock in mycobacteria based on a transcriptional control circuit. The circuit encodes differentially-activated positive and negative feedback regulators, which enable autonomous, self-sustained oscillatory gene expression with an average period of 4.5 hours. I modeled robustness and tunability of oscillation period and amplitude computationally and verified them experimentally. I also used this oscillatory circuit transcriptionally to regulate one of the transcription factors (KstR), and profiled in vivo temporal dynamics of KstR and KstR-regulated gene targets by dual-color fluorescence intensities in single Mycobacterium smegmatics cells. I observed bifunctionality (activation and repression) of KstR-regulated gene expression, and different gene targets exhibited differential, characteristic response times. This constituted a proof-of-concept that one can utilize a genetic oscillator to characterize dynamical regulation of transcription factors underlying a complex regulatory system. Additionally, it presents a potential new strategy for using dynamical system modeling to guide genetic engineering of mycobacteria for future therapeutic applications.
Suffering masculinity like an illness: gender fictions and cultural traumas, 1880-1950
(2013) Champion, Jared Neil; Chodat, Robert; Moore, William
My dissertation uses an interdisciplinary American Studies approach that blends literary and historical analysis to investigate social mechanisms that position white, straight, affluent men atop the American social hierarchy. Each chapter complicates myths about white American manhood, namely that hegemonic masculinity is (or ever was) a stable marker of privilege. Instead, I treat masculinity as a form of anxiety–creating panic. The project examines a series of historical moments when myths of manhood collapse. Chapter One situates the writing of William Dean Howells as the product of anxious manhood following the Civil War. Previous models of manhood, specifically those of Thomas Jefferson, exclude African-American men from manhood by denying citizenship. Rather than citizenship, Howells turns to Darwinian evolution to argue that white American men are an entirely new species. In Chapter Two, I discuss Theodore Roosevelt's oscillation between Darwinian evolution-"survival of the fittest" - and Lamarkian evolution, which contends that characteristics shaped by individual experience can be passed down from one generation to the next. Chapter Three examines the rhetoric of Benton Mackaye, the founder of the Appalachian Trail, and Stephen Mather, first director of the National Park Service, to show two distinctly different attempts to salvage agrarian manhood during American urbanization. Mackaye suggested a "barbarian invasion" of cities, and Mather paved the way for spiritually restorative auto-tours of the national parks. Chapter Four juxtaposes John Steinbeck's The Grapes of Wrath with Dorothea Lange's photograph, "Migrant Mother". While Congress debated whether Steinbeck's Depression-era novel was true, Lange's photograph was immediately placed in the national archives as an example of documented reality, despite its having been carefully staged. Steinbeck's novel undercuts patriarchal authority while Lange's renders it temporarily short-circuited, a dynamic that accounts for drastic differences in reception. Finally, Chapter Five places John Cheever's satirical take on 1950s gender in the short story, "The Country Husband", against the iconic post-WWII photograph, "War's End Kiss". The story challenges white American male authority and shows manhood as inherently contradictory and unstable in the post-war period, while the photograph seeks to restabilize masculinity.
Network-based methods to identify mechanisms of action in disease and drug perturbation profiles using high-throughput genomic data
(2013) Pham, Lisa M.; Kolaczyk, Eric
In the past decade it has become increasingly clear that a biological response is rarely caused by a single gene or protein. Rather, it is a result of a myriad of biological factors, constituting a systematic network of biological variables that span multiple granularities of biology from gene transcription to cell metabolism. Therefore it has become a significant challenge in the field of bioinformatics to integrate different levels of biology and to think of biological problems from a network perspective. In my thesis, I will discuss three projects that address this challenge. First, I will introduce two novel methods that integrate quantitative and qualitative biological data in a network approach. My aim in chapters two and three is to combine high-throughput data with biological databases to identify the causal mechanisms of action (MoA), in the form of canonical biological pathways, underlying the data for a given phenotype. In the second chapter, I will introduce an algorithm called Latent Pathway Identification Analysis (LPIA). This algorithm looks for statistically significant evidence of dysregulation in a network of pathways constructed in a manner that explicitly links pathways through their common function in the cell. In chapter three, I will introduce a new method that focuses on the identification of perturbed pathways from high-throughput gene expression data, which we approach as a task in statistical modeling and inference. We develop a two-level statistical model, where (i) the first level captures the relationship between high-throughput gene expression and biological pathways, and (ii) the second level models the behavior within an underlying network of pathways induced by an unknown perturbation. In the fourth chapter, I will focus on the integration of high throughput data on two distinct levels of biology to elucidate associations and causal relationships amongst genotype, gene expression and glycemic traits relevant to Type 2 Diabetes. I use the Framingham heart study as well as its extension, the SABRe initiative, to identify genes whose expression may be causally linked to fasting glucose.
Innovation in dynamic oligopoly and corporate taxation with financial frictions
(2013) Kim, Myongjin; Rysman, Marc
This dissertation consists of three essays that study the strategic responses to used-goods markets in the aircraft manufacturing industry and the corporate taxation with financial frictions. The first chapter examines the relationship between innovation, production, and used-good markets. This study sheds new light on the crucial role of innovation as a competitive tool against used-good markets. I estimate heterogeneous consumer demand and production and innovation decisions of oligopolistic firms using a unique data set covering the wide-body aircraft manufacturing industry from 1969 to 2011. My main finding predicts that firms develop new products more frequently and produce less quantity in the presence of active used-good markets. The second chapter estimates a dynamic structural model of Airbus, Boeing and the used airplane market, and then evaluates government subsidies to Airbus and Boeing, which have recently been ruled illegal by the WTO. I first recover dynamic production costs for each product and dynamic innovation costs. Using the estimates of the dynamic structural model, I find that a production or R&D (research and development) subsidy reduction leads to a delay in firms' innovation; in the aircraft manufacturing industry, a production subsidy reduction has a bigger negative impact on innovation than a subsidy reduction in research and development. I further find that, though it reduces innovation and production, the cut in the government subsidies has a minor effect on consumer welfare due to the presence of active used-goods markets. The third chapter examines corporate taxation in the presence of financial friction. The financial crisis of 2007-2009 demonstrated that excessive debt financing by firms makes the economy as a whole vulnerable in a crisis. I develop a model that includes informational friction between borrowers and lenders as well as tax advantages of debt. This allows me to quantify the impact of a removal of the tax advantage of debt. I find that abolishing the tax deductibility of debt reduces aggregate debt holding by about 15-20% in the long run. This reduces corporate default rates and thus mitigates the economy's sensitivity to financial shocks.
Non-parametric Bayesian prediction of landmark times for analysis of failure-time data
(2013) Lustgarten, Stephanie; Doros, Gheorghe
In clinical trials with failure-time primary outcomes, also known as "event-driven" designs, the statistical information is determined by total observed events. Examples of failure-time clinical trial endpoints include: time to death and time to disease progression. In trials with event-driven designs, the interim and final analyses are performed after a pre-specified number of events have been observed, based on a priori design considerations, rather than after observing patients for a pre-specified period of time. The timing of these analyses represent important milestones in the conduct of the study. In particular, if a trial requires review of interim analyses by a Data Monitoring Committee (DMC), convening the DMC members requires much advance planning and effort. In addition, advanced knowledge of when these milestones will occur can allow trial sponsors to make informed decisions regarding resources and financial planning. It is therefore of interest to predict when a pre-specified number of events will be observed based on accumulating data. Parametric and semi-parametric methods have been proposed for event prediction when data are right censored. In cases when the underlying failure time distribution is unknown or accumulated events are relatively sparse, these methods may not provide accurate or efficient prediction. We propose a method to predict the number of events that is a fully Bayesian non-parametric approach in modeling the survival probabilities that is more flexible and generalizes to interval censored data. We use a Gibbs sampler to sample from the posterior of the survival distribution to obtain point and interval estimates for the specified number of events. We compare the accuracy and precision of this approach to proposed parametric and semi-parametric methods under a variety of data generating mechanisms, beginning with right-censored data. We then extend the study to interval-censored data, comparing the methods under data generated from varying assessment intervals. Finally we consider the scenario in which we are blinded to treatment assignment, incorporating a Bayesian approach to determine the probability of membership to a particular treatment group. We demonstrate the proposed method offers greater flexibility and has the ability to match or outperform existing methods under multiple clinical trial scenarios.
Characterization of an Arabidopsis aminotransferase that participates in tryptophan metabolism and auxin homeostasis
(2013) Pieck, Michael L.; Celenza, John L., Jr.
The phytohormone indole-3-acetic acid (IAA) plays a critical role in regulating numerous aspects of plant growth and development. Biochemical evidence indicates that IAA can be synthesized both from tryptophan [Trp; Trp-dependent (D) pathways] and from an indolic precursor of Trp [Trp-independent (I) pathways]. At the genetic level, there is much support for Trp-D pathways, but there is little genetic evidence for Trp-I pathways. Mutants with altered Trp-I IAA synthesis were identified from genetic screens using the model plant Arabidopsis thaliana. From these screens, the allelic iss1-1 and iss1-2 mutants were identified that displayed an indole-dependent IAA overproduction phenotype consisting of fused leaves and increased lateral and adventitious root growth. iss1 mutants appear wild type (WT) when grown on medium supplemented with Trp. Using stable isotope labeling studies, iss1 and WT were both found to use primarily Trp-D synthesis when grown on unsupplemented medium. In contrast, iss1, but not WT, used primarily Trp-I synthesis, when grown on indole-supplemented medium. Surprisingly, iss1 seedlings also have a 170-fold increase in Trp when grown on indole, indicating that the increase in Trp-I IAA is not due to a loss of indole to Trp conversion but is suggestive of a role for ISS1 in Trp catabolism. Using map-based cloning, ISS1 was identified as an uncharacterized aminotransferase that is distantly related to aromatic aminotransferase (AroATs). ISS1 is highly conserved across the plant kingdom; however none of these ISS-related genes have been characterized. To demonstrate that ISS1 is an AroAT, heterologous expression of the ISS1 cDNA was found to fully rescue the yeast aro8 aro9 double mutant that is defective in redundant AroATs needed for the production of phenylalanine (Phe) and tyrosine (Tyr) in yeast. Based on the data presented in this thesis, the most likely role for ISS1 in planta is in Trp catabolism. However, the iss1 mutant also showed a decrease in the Phe-derived metabolite, coniferin, suggesting an additional role (either direct or indirect) for ISS1 in Phe metabolism. Although the precise role of ISS1 remains to be determined, these results presented provide genetic evidence for the existence of the Trp-I IAA pathway.
Essays on employment dynamics and asset prices
(2013) Siemer, Michael; Gourio, François
This dissertation consists of three essays that examine the importance of financial constraints and uncertainty for employment outcomes and asset prices. The first chapter documents that the recession of 2007-2009 has been characterized by: (1) a large drop in employment concentrated in small firms, (2) an unprecedented decline in the number of firms, and (3) a slow recovery. I study if these observations can be reconciled in a theoretical model. I develop a heterogeneous firm model with labor adjustment cost, endogenous firm entry, and financial constraints that generates these key facts. The model further predicts that a large financial shock results in a long-lasting recession when the model is calibrated to match the firm size distribution. The second chapter provides empirical evidence that financial constraints affected employment growth most strongly in young small firms during the 2007-2009 recession. I use a confidential firm-level employment data from the Bureau of Labor Statistics and financial data from Compustat to construct a sector level external financial dependence measure. I find that in the period of 2007-2009, small and young firms in sectors with high external finance dependence exhibited lower employment growth than those in low external finance dependent sectors. The effect of external finance dependence on employment growth in small and young firms is largely driven by firm entry and exit. For large firms I do not find a significant difference between sectors of difference external financial dependence. The third chapter studies the asset pricing implications of learning about economic uncertainty in an endowment economy. This work is motived by the widely held belief at the beginning of the 2007-2009 financial crisis that the economy might be at the onset of another Great Depression. Economic uncertainty in the model takes the form of rare events that are not directly observed. We show that when agents employ Bayesian learning rules, learning endogenously introduces a time-varying risk premium. The theoretical model is able to match several empirical asset-pricing facts including the risk premium and the predictability of returns.
The p-adic Shintani cocycle and p-adic L-functions
(2013) Steele IV, George Alexander; Stevens, Glenn
The Shintani cocycle on GL_n(Q), as constructed by Hill, gives a cohomological interpretation of special values of Shintani zeta functions. We interpret this cocycle as taking values in a module, introduced by Stevens, of locally polynomial p-adic distributions localized with rational poles. Our first theorem shows that the Shintani cocycle takes values in the sub-module of locally analytic distributions with rational poles. Next, we give a simple criterion for the Shintani cocycle to specialize to true p-adic distributions. The theorem shows that such specializations are automatically p-adic measures. We give two applications of these theorems: First, we recover the p-adic L-functions of totally real fields. Our construction greatly simplifies the original constructions of Deligne-Ribet, Cassou-Nogues, and Barsky, and we anticipate the methods will be useful for studying refinements of the Gross-Stark conjecture. Second, we give a simple construction of the p-adic L-function of critical slope Eisenstein series, proving a conjecture of Pasol and Stevens. The results of this construction were recently and independently proven by Bellaiche and Dasgupta, but our methods side-step many of the technical hurdles present in their construction.
In vitro evaluation of optical coherence tomography in the detection of intact dentin and various anomalies within root canal systems
(2024) Dhaliwal, Gagan; Chogle, Sami M.
Optical Coherence Tomography (OCT) is a non-invasive diagnostic technique that utilizes near infrared light to image biological tissue microstructures. Previous research by current authors has shown the potential of OCT as an instrument to provide detailed information about the internal root canal without exposure to radiation. This study was set up to confirm the efficacy of the OCT using a catheter-based imaging probe for detection of intact dentin and modifications within root canals. Dental anomalies or areas of interest for imaging were selected to be internal resorption, vertical root fracture, horizontal root fracture, lateral canal, and bifurcation. This project used the St. Jude/Abbott OPTIS Integrated System, Dragonfly OPTIS Imaging Catheter, dental microscope, extracted teeth with single canals, a vacuum base vise, and handfiles. 11 teeth were selected via inclusion criteria and underwent preparation to simulate anomalies, followed by root canal analysis using OCT. This study determined (1) the minimal apical diameter of 0.9mm needed to fit the OCT catheter to the apex (2) confirmed consistency of method with repeated use, (3) verified presence of simulated anomalies, and (4) established continued functionality after alteration of catheter. In conclusion, OCT has the potential to be a viable diagnostic tool in endodontics.
Measuring the effect of sensory information alterations on robotically assisted dental implant accuracy in a novel 3D printed model
(2024) Johnson, Ryan David Patrick; Price, Albert
Sense of touch is a crucial component of successful dental implant surgery. The ability to differentiate internal bone microstructure during the drilling process allows clinicians to make needed adjustments to “drift” during the implant osteotomy preparation. As dentists have increasingly employed computer-assisted placement with surgical guides, the neural feedback to the surgeon’s hand has decreased. The Yomi dental robot provides replacement guidance using substitutes for this haptic feedback in addition to enhanced sensory input (visual and auditory). How this combined sensory information affects the executed implant position in comparison to the planned position is the subject of this study. The goal was to design a 3D printed practice model to be used for training in Yomi robot assisted implant placement and then to evaluate how altering combinations of sensory information might affect final implant position. A printed model was created after several prototypes were tested. However, before experimental implant placement could begin, it was found that the available printing process was inconsistent. Models could not be replicated due to errors in printing. The progress in study design, process for model design and creation and technical limitations are described in this paper.
Pet ownership and its association with the oral health of older adults
(2024) AlMugbel, Khuloud Khalid S.; Scott, Thayer
OBJECTIVE: To explore the effect of pet ownership (PO) on the oral health of older adults. METHODS: NHANES data 2005-06 was analyzed (logistic/linear regression), restricted to aged 65 years and older. The outcomes of interest were the presence/absence of untreated dental caries, the presence/absence of dental restorations, and mean number of teeth. The primary independent variable was PO status within the past year. Potential confounders included demographic data (age, gender, race, marital status, poverty income ratio, education), smoking status, depression, physical activities, and mean sugar intake, taking into account NHANES complex sampling. RESULTS: Individuals aged 65-69 were more likely to own pets than those older than 70 years, with dogs being the most popular pet (62%) followed by cats (31%). After adjusting for potential confounders, there was no association between pet ownership in seniors and the outcomes of interest. Non-Hispanic blacks reported the highest tooth loss (-6.42 teeth) among the racial groups and were 40% less likely to have a dental restoration. In the unadjusted model Mexican Americans have 2.83 times the odds of untreated dental caries compared to Non-Hispanic whites, while current smokers had 7 fewer teeth than those who never smoked. CONCLUSIONS: Pet ownership was not associated with improved oral health for older adults. Despite the lack of oral health protection, pet ownership provides companionship, reduces loneliness, and increases socialization among older adults.
The role of TNFAIP1 in regulation of LPS/TNF-ɑ-induced signaling pathway
(2024) Tangkham, Thanarut; Tang, Xiaoren
INTRODUCTION: Porphyromonas gingivalis (P.g), a gram-negative anaerobe, is the major bacterium in the red complex (Socransky et al. 1998) and responsible for the onset and progression of severe periodontal disease. P. gingivalis is currently considered the ‘keystone’ pathogen of periodontal disease. It can produce several virulence factors, such as cysteine proteinases (gingipains), lipopolysaccharide (LPS), capsule and fimbriae. The LPS plays an important role in periodontal disease by inducing inflammation via stimulation of some cytokines such as TNF-ɑ. TNF-ɑ can activate expression of early response genes in macrophages, including Tumor Necrosis Factor-?-Induced Protein 1 (TNFAIP1). However, the role of TNFAIP1 in LPS-induced inflammation is largely unknown. OBJECTIVE: 1. Identification of TNFAIP1 biological functions in response to LPS/TNF-ɑ; 2. Identification of the TNFAIP1 mediated signaling pathway; 3. Determination of factors involved in the TNFAIP-dependent signaling pathway; 4. Analysis of TNFAIP1 promoter activity. MATERIALS AND METHODS: Mouse RAW cells, human THP-1 cells or MC3T3 cells were cultured in RPMI or ɑ-MEM media with 10% FBS at 37°C in 5% CO2. For DNA construction of TNFAIP1 cDNA or its promoter, DNAs were generated by polymerase chain reaction (PCR) with specific primers and templates. The cloned DNA sequences were confirmed by sequencing. Experiments to identify the biological function of TNFAIP1 and its promoter activity, utilized ELISA, DNA recovery, western blot, protein array, and promoter assay. RESULTS: 1. LPS-induced the activation of p-MARK or p-PI3K (but not p-JAK), the production of TNF-ɑ, NFĸB or TNFAIP1 was confirmed by ELISA and western blot analysis; 2. Transfection of TNFAIP1 cDNA for 1-10 hours stimulated TNF-ɑ production in macrophage cells but not after longer exposure; 3. Caspase 1 and 3 were induced by TNFAIP1 after transfection of TNFAIP1 for 20 hours; 4. Overexpression of TNFAIP1 induced apoptotic proteins, such as Bcl-x, Caspase 3, Catalase, Claspin, Cytochromic, HO-1/HMOX1/HSP32, MCL-1, P27/Kip1, or SMAC/Diablo; 5. TNFAIP1 promoter DNA was cloned into pGL3 basic plasmid DNA to determine promoter activity. TNFAIP1 promoter activity was tested via its potential protein-protein interaction using luciferase gene expression. With a MAPK inhibitor, TNFAIP1 promoter activity was increased. In contrast, with an ATK inhibitor, TNFAIP1 promoter activity was reduced. CONCLUSIONS: 1. TNFAIP1 is an important factor of the LPS/TNF-ɑ-dependent pathway; 2. MAPK or PI3K functions as an upstream factor of TNFAIP1, and LITAF is downstream factor of TNFAIP1-mediated signaling pathway in response to LPS; 3. Transfection of TNFAIP1 cDNA stimulated TNF-ɑ production for 1-10 hours exposure but reduced it for 10 - 20 hours exposure; 4. Overexpression of TNFAIP1 can increase expression of apoptotic proteins, Bcl-x, Caspase 3, Catalase, Claspin, Cytochromic, HO-1/HMOX1/HSP32, MCL-1, P27/Kip1, or SMAC/Diablo; 5. AKT and MAPK may act as transcriptional regulators of TNFAIP1 gene by binding to the promoter region. AKT upregulates TNFAIP1 gene expression and MAPK downregulates TNFAIP1 gene expression.
Early marginal bone loss around dental implants: a retrospective cohort
(2024) Alyaeesh, Abdulaziz; Dibart, Serge, DMD, DDS; Price, Albert M., DMD
AIM: To evaluate marginal bone loss around dental implants at the 2nd stage abutment surgery and retrospectively evaluate the association of pre-surgical variables. MATERIAL AND METHODS: Eighty-seven subjects (41 Males and 46 females) were enrolled in this cohort. The subjects' ages ranged from 23 to 80 years. Two endosseous implant brands were utilized: Nobel Biocare and Straumann Bone Level . Clinical measurements (mesial, distal, buccal, and lingual) were recorded from the coronal margin of the implant platform to the bone margin with a periodontal probe (Williams periodontal probe, Hu-Friedy) at the time of implant placement and at the 2nd stage abutment surgery. The pre-surgical variables (medication intake, implant site, bone graft volume, membrane type, and smoking) were evaluated using Chi-square test. RESULTS: The marginal bone loss (MBL) difference was calculated. The Mean clinical MBL: Mesial = 0.71 mm, Distal = 0.56mm, Buccal/Labial = 0.65 mm, and Lingual/Palatal = 0.56 mm. The test showed no statistically significant difference between test and control subjects in each of the variables, with the exception of thyroid medication. A statistically significant (P value = 0.011) association was found between levothyroxine and MBL at the mesial measurement. CONCLUSION: This limited cohort study suggests that medication-controlled hypothyroidism patients may experience an increased risk of marginal alveolar bone loss around dental implants at the 2nd stage abutment surgery. The final determination will be recalculated when the study population reaches the estimated requirement of 200 subjects.
The use of KRAS and CDK inhibitors in the treatment of brain metastases in pre-clinical models
(2024) Sadeh, Yinon; Offner, Gwynneth D.; Wakimoto, Hiroaki
Brain metastases (BMs) present a formidable obstacle across various primary cancer types, notably small cell lung cancer (SCLC), non-small cell lung cancer (NSCLC), melanomas, and breast cancers. In this investigation, we aim to evaluate the potential of genotype-guided targeted therapy while addressing the challenges of co-existing genomic alterations frequently encountered in BMs. This research explores the efficacy of adagrasib (MRTX849), a KRAS G12C inhibitor, and abemaciclib, a CDK 4/6 inhibitor, both individually and in combination against BMs originating from NSCLC cell lines harboring KRAS G12C and CDKN2A mutations. Utilizing a diverse array of methodologies encompassing cell viability assays, cell death assays, western blot analyses, and in vivo xenograft models, we elucidate both the therapeutic potential and underlying mechanisms. Distinct responses to adagrasib and abemaciclib monotherapies were observed across two different cell lines, underscoring the necessity for tailored treatment strategies. While adagrasib exhibited variable efficacy, abemaciclib consistently inhibited CDK 4/6 activity. Notably, the combination therapy demonstrated synergistic effects, suggesting a promising approach for enhanced therapeutic outcomes. Our findings from both in vitro assays and western blot analyses corroborate targeted pathway inhibition, although the observed pathway reactivation underscores the importance of optimizing dosing strategies. In vivo studies further support our in vitro findings, demonstrating efficacy but also raising concerns regarding toxicity with combination therapy. Pharmacokinetic / pharmacodynamic (PK/PD) analyses underscore potential advantages of combination therapy in terms of systemic exposure and brain penetration. Despite histological evidence of therapeutic effects, discrepancies between in vivo and in vitro caspase-dependent apoptosis results highlight the complexity of tumor biology and the challenges of translation. By Focusing on personalized treatment approaches and addressing therapeutic hurdles, this work establishes the foundation for clinical investigation in advancing the management of BMs and improving treatment outcomes in NSCLC patients.
“The point is intimidation”: learning from practicing U.S. secondary history teachers about teaching in politically turbulent times and contexts
(2024) Funk, Lauren; Martinelle, Robert
Polarization in the United States and controversy over the teaching of content some deem “divisive” has resulted in the enactment of restrictive legislation in many states. Such constraints contribute to a fraught environment in schools today and significantly impact the work of teaching. Utilizing frameworks of ambitious teaching and principled resistance, this dissertation sought to understand the experiences of three secondary social studies teachers in Florida, Tennessee, and Texas as they navigated and resisted these constraints. Through an analysis of interview data, the study found that teachers engaged in ambitious teaching and principled resistance by enacting their political clarity and legal literacy. Additionally, data supported the importance of teachers building solidarity and support systems within schools and beyond their walls. Their stories illuminate some of these teachers' obstacles, including informal conflict and more formal challenges to their curricula and instruction. Teacher narratives help to better understand the impact of mandates and policies that can be harmful. However, as these participants demonstrate, they also present opportunities for teachers to be agentic and resist efforts to constrain their practice. These findings offer implications for theory, policy, practice, and teacher preparation. While the policymaking around “divisive concept” legislation has not been made in good faith and has purposefully sowed fear and uncertainty for educators and school communities nationwide, understanding teachers’ reactions to these laws and policies can pull back the curtain on the in-school impact and the reality of social studies instruction.

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