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Phospholipid membrane remodeling through exogenous fatty acid incorporation in certain bacterial species
Get PDFMulti-drug resistant bacteria have become problematic in healthcare settings. Recent studies have documented the ability of some bacteria, such as Vibrio species, to assimilate exogenous fatty acids into their membrane phospholipids. Therefore, the current research was performed to determine whether the three virulent, multi-drug resistant bacteria Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli can remodel their cell membranes following exposure to a range of exogenous polyunsaturated fatty acids (PUFAs). Furthermore, we hypothesized that PUFAs would influence phenotypes associated with growth and virulence. Extracted phospholipids were examined by UPLC/MS analysis to confirm assimilation of exogenous PUFAs into the bacterial phospholipids. A. baumanii, K. pneumoniae, and E. coli were found to incorporate all exogenous PUFAs into their cell membranes, with the exception of docosahexaenoic acid (22:6) for E. coli. Membrane permeability assays were performed using Crystal violet (CV) and ethidium bromide (EtBr). Notably, E. coli samples exposed to 22:6 or arachidonic acid (20:4) took up approximately 35% or 60% more CV than the control sample, respectively. All PUFA-exposed E. coli samples demonstrated higher uptake of EtBr than the control sample, suggesting that every fatty acid tested increased membrane permeability. An assay for biofilm formation revealed that α-linolenic acid (18:3α), γ-linolenic acid (18:3γ), 20:4, and 22:6 significantly (p \u3c 0.002) increased biofilm production in E. coli. Strikingly, 18:3 γ and 20:4 tripled biofilm formation when compared to the control sample. Similar phenotypic shifts were observed in A. baumannii and K. pneumoniae. Motility assays and minimum inhibitory concentration (MIC) assays using membrane-active cyclic peptide antibiotics were also performed. Taken together, the results of the experiments presented in this thesis suggest that exogenous PUFAs may be utilized in the future as combatants of multi-drug resistant bacteria in conjunction with antibiotics
A meta-analysis of interventions to reduce repeat pregnancy and birth among teenagers
Get PDFAlmost 20% of teen mothers have more than one child before age 20. Researchers have implemented many interventions to prevent subsequent births. The purpose of this study was to examine their effectiveness in preventing repeat pregnancy/birth. We searched nine electronic databases for eligible studies conducted through September, 2014; 47 primary studies met our criteria and provided 52 comparisons. We coded the primary studies for characteristics related to study source, participants, interventions, methods, and outcomes. Using meta-analytic techniques, we calculated intervention effect sizes (ESs) on repeat pregnancy/birth within three time periods: \u3c15 months after the first\u3ebirth, 15-35 months, and after 36-60 months. Primary studies included 219,086 teen mothers with a mean age of 16.9 years. Interventions had a medium effect in reducing repeat pregnancy/birth for each time period. Teen mothers who received an intervention had 36-60% lower rates of repeat pregnancy/birth than control/comparison mothers. Of the many moderators examined for each time period, only a few explained additional variance. Our results indicate that interventions are moderately effective for as long as 60 months after a prior teen birth. It remains unclear which interventions are most effective, for which teens, and under what circumstances
Evaluation of the performance of polyurethane foams in rigid pavement preservation
Get PDFAfter several years of service, concrete pavement slabs tend to settle due to weak subgrade or erosion of the subgrade soil. Different treatment techniques have been used to rectify the problem. In recent years, high-density polyurethane (HDP) foams were introduced on concrete pavements after their success in leveling settled sidewalks and building bases/foundations. Compared to other traditional slabs jacking/stabilization material, HDP foams are cost-effective, their installation requires shorter lane closure times and protects the subgrade from subsurface water infiltration by filling the voids. In 2015 and 2016, the Tennessee DOT applied HDP material on sections of Interstate I-24 and I-75 in Chattanooga, Tennessee to lift and level settled concrete pavement slabs. Longitudinal profiles data were collected using a standard high-speed inertial profiler before and after application of the material to assess the performance of the treated sections over time. These data were evaluated by using the profile viewing and analyzing (ProVAL) software to compute the international roughness index (IRI) and the transverse joint faulting. Results show that application of HDP foams did neither improve nor retrogress the pavement condition but maintained it in its state before application of the material. This study recommends an in-depth ground investigation to be carried out before injection of the material, establishment of a standardized protocol for selecting pavement sections suitable for HDP foam injection, and contractors to use sophisticated leveling equipment, instead of the adjacent slab as a reference, to avoid accumulation of errors due to over correction
Racial Differences in the Impact of Adolescent Depression on Families in TADS
Get PDFThis manuscript examines racial differences in the impact of adolescent depression between White, African American, and Latino families. Findings are from the Treatment for Adolescents with Depression Study (TADS), a multi-site clinical research study evaluating the efficacy of CBT and Fluoxetine for treating adolescents with major depressive disorder. Primary caretakers of 439 adolescents with depression were interviewed. Results demonstrated that compared to White families, African American and Latino families were more likely to report increased feelings of tiredness or anergia (p\u3c.05) and more physical health problems (p\u3c.01) associated with caring for a depressed teen. The conclusion suggests the need for a better understanding of depression in people and families of color and offers recommendations for further research
Quantifying and qualifying the links that bind
Get PDFEmployees’ links to organizations and coworkers represent an important factor related to many work-related constructs in the Industrial-Organizational (I-O) Psychology literature. Often, I-O researchers conceptualize these employee links through either the number of workplace links or an employee’s perceived social support. However, these conceptualizations are potentially limited. Research into Social Network Analysis has investigated different quality dimensions in links (e.g., link strength and valence) which can significantly influence outcomes in social, workplace, and general well-being contexts. Thus, the present thesis project was undertaken to explore whether incorporating these quality dimensions of link strength and link valence adds any incremental utility to our understanding of workplace constructs. Bivariate and partial correlation analyses were used to test hypotheses. Results indicated partial support for both link strength and link valence as new constructs for measuring links
Using Past Surveys of Attitudes to Predict Current U.S. Military Retention
Get PDFRetaining qualified active duty members in the military is an essential mission for DoD. This research presents findings on the relationship between an active duty member’s plans to stay on active duty (as indicated on a survey) and the member\u27s actual retention behavior in the U.S. military two and four years later. Retention plans, as measured on the DoD’s Status of Forces Surveys, have often been interpreted as an indicator of subsequent retention behavior, but the relationship between survey responses and actual retention behavior has not been verified using actual retention data. This study seeks to examine this relationship. Further, in cases in which a service member indicated high retention plans, but did not remain in the Military, it may be valuable to explore factors that have led to this change. Recent transactional data of U.S. military separation codes was restructured among time dimensions and military rank criteria and compared against prior survey data measuring retention plans. Employing weighted logistic regression analyses, retention plans were used to predict a dichotomous outcome of actual retention behavior (i.e., “retained” or “left”). Moreover, predicted probabilities were used to show how actual retention behavior varies as members indicate higher and lower levels of plans to remain on active duty. Analyses showed that an active duty member’s plans to stay on active duty had a positive relationship with actual retention behavior two years later and a stronger relationship four years later. Chief among the findings were that Marine Corps members and junior enlisted member were less likely than members in other Services and paygrades to remain in the Military after two and four years. However, the relationship between retention plans and actual retention behavior was stronger among these subpopulations (Marines, junior enlisted) than members in other Service and paygrades. This research is part of a larger body of on-going research that seeks to implement data wrangling techniques to merge survey data with transactional administrative data, augmenting the use of survey items in predicting retention outcomes. Future research will focus on identifying factors related to a Service member indicating high retention plans but separating from the Military (i.e., those who, at one point, intended to stay, but separated 2-4 years later). Findings may support the Department of Defense in tailoring its policies and programs (i.e., promotional opportunities, family policy, etc.) to better support retention
Organizational Alignment through Leadership Proficiency and Human System Interventions
Get PDFAcross many organizations, agencies and programs have been tasked with building, training, and retaining the workforce needed. Yet, only few organizations have succeeded in their efforts by creating a culture in which workforce preferences align and overarching leadership support is provided. Such a cultural transformation requires not only a behavioral shift from employees, but especially from those in leadership positions, in order to break from the typical way that organizations have long encouraged them to behave. Although the importance of leadership has been emphasized in previous literature, no consistent description of leadership attributes or promising application of human system interventions currently exist to tackle those challenges. To understand leadership attributes and its accompanied behaviors within organizational settings, we hypothesized certain leader attributes in form of personality and communication behaviors to have a greater effect on organizational alignment and overall performance. Further, we hypothesized human system interventions in the form of leadership or group coaching to have a greater effect on leadership proficiency and ultimately on organizational alignment. The foundation of this research, here the conceptual model of leadership traits is based on a comprehensive literature review to specify leadership attributes into high-level categories of leadership communication and behaviors to align with employee preferences, thus improving cultural growth, and retention. Through a simulation-based platform the leadership proficiency attributes will be observed during a dynamic design team task. Students from the University of Alabama in Huntsville will be recruited to participate in this study. Both qualitative and quantitative data will be gathered about leader proficiency, efficiency and efficacy during the simulation. Leader qualities may be inevitable in fostering organizational alignment and cultural growth resulting in higher retention and lesser turnover rates. The data obtained will be analyzed to identify a) leadership attributes that support aligning employee preferences and b) the effect of potentially fruitful human system interventions as means for leadership, cultural and performance growth. Moreover, obtained results will be used to develop agent-based models with a focus on the representation of personality dependent attributes in models of agent interactions to display emergent agent behavior. The proposed research will identify attributes of leadership proficiency through experimental design as well as demonstrate how leadership interactions and attributes can be simulated in agent-based modeling. The goal of this research is to provide a state of the art overview of identified leadership attributes supportive towards organizational alignment and cultural growth. This is performed to advance leadership and cultural growth within organizations; and using results of the empirical and theoretical groundwork to develop in the field applications
Finding the early talent: Factors predicting early advanced math enrollment
Get PDFEarly exposure to advanced math classes have shown higher levels of college readiness for students. However, there is evidence of a discriminatory gap among students of marginalized backgrounds in placement of these advanced courses. To examine this, three years of data from approximately 10,500 student will be used to develop and validate predictive models that examines both enrollment and performance in advanced math courses in the eighth grade. Data will come from a longitudinal study taking place in rural North Carolina. This research will use the predictive models to determine which students will be selected for eighth grade advanced math and if there is a selection bias for which eighth grade students are chosen to begin advanced math classes
Design of a pneumatic conveying test loop for laboratory testing
Get PDFPneumatic conveying is the transportation of material through a closed conveying line in a gas medium via a pressure differential. In industry, pneumatic conveying is used extensively to handle materials: specifically, bulk solids and powders. 80% of all transported materials are bulk solids and pneumatic conveying is currently experiencing industry growth at a rate of 6.4% annually. Industrial pneumatic conveyor suppliers use specialized testing systems to make design decisions regarding specific applications, taking into account the conveyed material, the structure of the plant in which the system will be installed, and desired system characteristics such as necessary filtering or safety requirements. As interest in material conveying characteristics grows so does the demand for small-scale testing facilities. This paper explores the development of a highly versatile pneumatic conveying test loop for small-scale materials conveying characterization. This system is equipped with instrumentation which allows for data to be gathered regarding the velocity of particles in the flow, the pressure differential across the system, and the mass flow rate of air and material through the system. This allows for the change in material properties as well as system damage due to conveying to be analyzed. A pipeline with a 53 mm bore and a 41 m equivalent length, including 9 long radii 90° elbows, is specified. Additional system components discussed include a rotary air compressor, feeding hopper, rotary air lock feeder and filters for material separation. Instrumentation applied to this system includes a laser Doppler velicometer, which allows for particle velocities to be determined, a sight glass, which allows for flow phase to be determined, a pressure transducer, which allows for pressure changes in the system to be determined, a Coulombmeter, which allows for electrostatic charge build up in a system test section to be determined, and a hot wire anemometer, which allows for the velocity of air in the system to be measured before the introduction of conveyed material
Experiences of health communication within the family: Parent and adolescent perspectives
Get PDFBackground: Adolescence is a critical period for the development of health and well-being and is a pivotal time for transition toward independent health decision making. Family health communication patterns, can influence behaviors and attitudes of adolescents. Health literacy is a pre-requisite for acquiring and comprehending health information. However, minimal research exists examining the connection between health literacy and family communication. Purpose: To examine the risk of limited health literacy and explore the experiences of health communication among families. Methods: 9 Adolescents and 8 parents completed demographic questionnaires, the Newest Vital Sign and private semi-structured qualitative interviews. Glazer’s grounded theory approach was used to identify thematic categories and theoretic cores of the qualitative data. Results: Limited health literacy risk was 12.5% for parents and 22/2% for adolescents. Narrow definitions of health, evaluation methods of information, opportunity and interpretation were the identified themes. Conclusions: Results from our study suggest that within families who are not at risk for limited health literacy, health communication is occurring related to topics of interest to adolescents. These conversations persist despite parental perceptions of these conversations being negative. Further research should investigate parent motivation related to health communication and the role that health literacy may play in motivation toward and ability to engage in family health communication