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Identifying the Neurorehabilitation Paradigm Closest to the Natural Voluntary Gait in Healthy Mice
No full textAccording to National Institute of Health (NIH) (Spinal cord injury: hope through research, 2013), 12,000 spinal cord injuries occur in United States every year. More than a quarter of a million Americans are currently living with spinal cord injuries. There are currently no effective means to promote repair of injured spinal cord tissue. However, the neuronal structures necessary to allow standing and stepping are located below the site of SCI, and can be reactivated with training. In patients with chronic spinal cord injury, activity-based therapy has been seen to improve walking performance in adults. The general rehabilitation strategy to regain locomotor ability after SCI has been based on the principles of motor learning, including task-specificity, task-variability, feedback information and the intensity of training provided. Therefore, this study aimed to identify rehabilitation strategies that closely resemble the natural gait pattern of the lower limbs during locomotion in mice. Healthy mice were trained for several weeks before kinematic recordings were acquired for four neurorehabilitation paradigms: runway quadrupedal, runway bipedal (with the neurorehabilitation robot), treadmill quadrupedal and treadmill bipedal. Two different data analysis strategies provided converging results indicating that the treadmill quadrupedal paradigm was the closest to the runway quadrupedal or natural gait of the mice. Additionally, runway bipedal (with neurorehabilitation robot) appeared to be the furthest away from the natural gait of the mice. However, in contrast to these results, the findings from studies with injured mice showed significant improvement through the runway bipedal paradigm (with the neurorehabilitation robot) because it pushed the mice to perform voluntary locomotion as opposed to the treadmill bipedal or treadmill quadrupedal paradigm. It will be interesting to look at the neuronal circuits involved in healthy mice and injured mice for all the four paradigms along with the kinematic analysis to understand the functional mechanisms of neurorehabilitation after spinal cord injury in detail.Ph.D., Biomedical Engineering -- Drexel University, 201
New understanding of the effects of microtubule-associated proteins on dynamic instability, including the role of tau in neuronal function and disease
No full textAs morphologically complex and polarized structures, neurons are critically dependent on cytoskeletal function. Neuronal processes are formed and maintained on a backbone of microtubules, which not only act as a structural support for axonal growth and formation, but also play important roles through their dynamic instability. Proper microtubule function, and by extension axonal function, relies upon distinct sub-populations of highly dynamic and highly stable microtubules. The functional difference between these domains has increasingly been shown to play a role in how microtubules promote axonal growth and interact with microtubule-associated proteins. Current dogma suggests that microtubule degeneration in neurological disease may best be averted by using microtubule-stabilizing drugs. In contrast, we demonstrate how siRNA knockdown of Fidgetin, a protein that specifically severs unstable microtubules, can promote neuronal growth by enhancing labile microtubule mass. We also investigate the role of tau in microtubule dynamics, demonstrating that tau does not act as a stabilizer of microtubules but rather promotes the growth and retention of dynamic microtubules, while MAP6, another microtubule-associated protein with true stabilizing characteristics, acts in opposite fashion. These findings open a new path for research into the mechanisms of tau and the possibilities of using labile microtubule manipulation to treat disease.Ph.D., Neuroscience -- Drexel University, 201
Computational Modeling of Fracture and Associated Wave Propagation in Precipitate-Hardened Aluminum Alloys
No full textThe identification of early stages of damage is an important consideration for determining remaining useful life in critical structures such as aircrafts. In this context, previous experimental investigations on precipitate-hardened aluminum alloys, which is a widely used class of aerospace materials, confirmed the acoustic emission resulting from fracture of second phase particles, which in fact occurs early in the deformation process so that it can be considered a damage precursor. The experiments also identified correlations between crystallographic (e.g. grain boundaries) and property mismatches (e.g. of elastic modulus and hardness) at the microscale with fracture initiation sites. Motivated by these findings, the research work presented in this thesis develops a computational modeling approach targeting the investigation of fracture at the microscale of aluminum alloys. In addition, the resulting wave propagation occurring because of the acoustic emission following the fracture events at that scale, is explicitly modeled using the finite element method. Specifically, a crystal plasticity model is employed to model strain localizations near particles in the aluminum matrix. Then a numerical approach is developed to transfer the crystal plasticity results to an enriched continuum domain. Finally, the resulting wave propagation is investigated by linking implicit and explicit analysis. The results from this investigation confirmed the effect of the fracture initiation sites on the resulting wave characteristics while they also provide theoretical validation on the related experimental investigations of recording acoustic emission at the microscale.M.S., Mechanical Engineering and Mechanics -- Drexel University, 201
Using the voices of k-4 teachers to explore a reformed professional learning model: a qualitative case study
No full textThis qualitative case study explored K-4 teachers’ perceptions of and experiences with a reformed professional learning model. The ineffectiveness of former professional learning models for teachers in public school settings has led to a surge in reformed models for teacher professional learning and development. The prevalence of these innovative learning models created a need to explore and to measure the effectiveness of these reformed models for teacher learning. This study intended to capture teachers’ perceptions of a reformed professional learning model and its impact on their professional practices through the use of one central research question and two sub-questions focused on the features and descriptions of the new model. Teachers described the positive features of and the challenging experiences within the reformed model in order to inform future professional learning designs and components. A review of artifacts from two professional learning day evaluations of the reformed professional learning model, two four-person focus groups, and four individual interviews were utilized in order to explore teachers’ perceptions of the reformed model. The findings from this study communicated that the participants’ perceptions of the reformed model were influenced by the descriptions, experiences, impact, and constructive feedback of the reformed professional learning model. The themes which surfaced after analysis of the data identified essential features of effective professional learning models through the lens of the K-4 teachers: professional learning models should have a purpose and utilize collaborative design features; include choice and the presence of individualized options; incorporate active learning and engaging experiences with opportunities to reflect; and, finally, demonstrate coherence and continuity within professional learning options. The increase of reformed professional learning models in the field of education should coincide with the use of collaborative structures that consider the perceptions of teachers when measuring the effectiveness of reformed professional learning models.Ed.D., Educational Leadership and Management -- Drexel University, 201
Decreasing Wait Time and Increasing Satisfaction in Outpatient Endoscopy Procedures
No full textOutpatient procedures account for a vast number of medical procedures performed in the United States. The United States healthcare system seeks to provide services which are of the highest quality. Patient satisfaction is a major driver of services protocol. Hospital and outpatient facilities are highly motivated to provide care that meets or exceeds patient expectations. Efficient use of resources is necessary for continued solvency and provision of quality care. Patients expect to be treated in a timely manner by personnel who are well trained. Outpatient endoscopy unit time is resource dependent and delays can be a major source of patient frustration. This quality improvement project proposed that increasing efficiency through the utilization of daily pre-procedure huddles and scheduling of patients, based on actual procedure length versus standard thirty-minute interval arrival times would decrease wait time and increase patient satisfaction in outpatient endoscopy procedures. Retrospective analysis of preoperative wait time data and post procedure patient satisfaction survey data, for a two-week period, was performed and compared to data received during the two-week project implementation period. Descriptive statics analysis exploring trends of the patient satisfaction survey revealed no drastic change in the proportion of responses from pre-implementation to post-implementation. Analysis using a repeated measures ANOVA indicated that there were not differences in average pre-op time between pre-implementation and post-implementation. Keywords: Wait times, Patient Satisfaction, Wait Time and Patient Satisfaction, Safety huddlesD.N.P., Nursing Practice -- Drexel University, 201
The Application of a Standardized Handoff Approach in a Community Hospital Setting
No full textHandoffs are the transfer of care, involving communication of important clinical information, transfer of responsibility, and collaboration between clinicians, assuring safe transfer of care from one clinician or department to another. Inadequate handoffs may result in serious events that compromise patient outcomes and influence care provider’s perceptions of handoff processes. Handoff communication stood as a critical patient safety issue and was identified as being an area of risk at the project organization. This risk was associated with inconsistent phone report processes and low scores concerning handoffs on the AHRQ Hospital Survey on Patient Safety Culture. Using the Plan, Do, Study, Act quality improvement cycle, this project focused on the implementation of an evidenced-based standardized handoff tool to provide consistency in information transfer from the Emergency Department to the Medical Unit or Surgical Unit; and the Post Anesthesia Care Unit to the Surgical Unit. The goal of this project was to streamline processes, reduce waste. and promote quality communication of essential care elements to improve nurse’s perceptions of handoff transitions. As a part of this process, direct care nurses were involved in developing and implementing the handoff tool, with the goal of improving staff perceptions of handoff processes using the AHRQ Hospital Survey on Patient Safety Culture handoff and transition survey questions to evaluate the outcomes of quality improvement project. Results reflected no statistical change in any of the four handoff questions, although qualitative feedback did suggest positive implications associated with the implementation of the new handoff standard work. Keywords: patient handoff, clinical competence, quality of care, nurse perceptionsD.N.P., Nursing Practice -- Drexel University, 201
Sustained proinflammatory signaling contributes to neurodegeneration in Parkinson’s disease
No full textCurrent evidence suggests a causal role of inflammation in the pathogenesis of Parkinson’s Disease (PD). PD is a progressive neurodegenerative disorder that is associated with loss of dopaminergic neurons and the aberrant accumulation of alpha-synuclein fibrils called Lewy bodies (LBs) within the substantia nigra (SN) as part of its pathology. Importantly, alpha-synuclein fibrils are capable of interacting with toll-like receptor 2 (TLR2) on both neurons and microglia to induce an inflammatory response. Previous work has investigated the effects pre-existing inflammation on neurodegeneration, however the relationship between pre-existing peripheral inflammation on alpha-synuclein fibril induced brain pathology in an animal model of PD is not known. Our study thus sought to understand the downstream signaling effects of activating two known pro-inflammatory receptors TLR2 and IL-1R1 in vitro and the effects of peripheral inflammation preceding alpha-synuclein-induced PD pathology in vivo. Our preliminary studies demonstrated the expression and functionality of IL-1R1 in SH-SY5Y cells. Activation of either TLR2 by PAM3CSK4 or IL-1R1 by IL-1[beta] caused a decrease in expression of phosphorylated ERK1/2 and promoted cell death in SH-SY5Y cells. We also observed that activation of either TLR2 or IL-1RI induced an increase in IL-1RI expression in SH-SY5Y cells. Taken together, these results suggest a crosstalk between TLR2 and IL-1RI that we infer may be essential in the degeneration of the dopaminergic neurons in the SN. Moreover, prior exposure to a low dose of lipopolysaccharide (LPS) systemically increased the expression of IL-1[beta], phosphorylated-ERK1/2, and nuclear factor of kappa light polypeptide gene enhancer in B-cells, alpha (I[gamma]B[alpha]) compared to animals that received saline. Animals that received both LPS and alpha-synuclein pre-formed fibrils (PFFs) exhibited increased phosphorylated-ERK1/2 and I[gamma]B[alpha] expression compared to animals that received either LPS or PFFs only. These findings suggest crosstalk between TLR2 and IL-1R1 signaling via altered ERK1/2 and NF-[gamma]B activity, increased IL-1[beta] expression that collectively lead to exacerbation of the inflammatory response during PD pathogenesis.M.S., Pharmacology and Physiology -- Drexel University, 201
African American Parents' Involvement in their Adolescent Children's Urban High School Experiences: A Narrative Inquiry
No full textThe myth of low to no African American parent involvement can be attributed, in part, to a perception of their limited presence in schools, especially at the high school level (Barton, Drake, Gustavo-Perez, St. Louis & George, 2004). Often, teachers declare that African American parents' do not care about their children's education (Archer-Banks & Behar-Horenstein, 2008). African American parents counter this stereotype by arguing that schools are unwelcoming spaces (Henderson, Mapp, Johnson, & Davies, 2007). Moreover, scholars suggest that the ways African American families support the academic achievement of their teenage children often go unnoticed by teachers who are more accustomed to middle class approaches to parent involvement (Kim, 2009; Hornby & Lafaele, 2011). Scholarship reveals that both individual and institutional barriers contribute to the perceived lack or low involvement of African American parents in their teenage children's urban high schools. The purpose of this dissertation research is to explore how the parents of African American high school students identify and negotiate the individual and institutional barriers to their active involvement in their teenage children's schools. The guiding research questions reads: How do African American parents identify and negotiate the individual and institutional barriers to their active participation in their adolescent children's urban high schools? This narrative inquiry consists of interviews with twelve African American parents and grandparents across different urban high schools, including public and charter schools, in Philadelphia, PA. Analysis of the interview data reveals three findings: 1) Contrary to common misperceptions, African American parents are involved in their children's education in ways that are consistent with traditional forms of parent involvement; 2) African American parents identify and negotiate barriers to their children's education by way of their culture; and 3) African American parents identify and negotiate barriers to their children's education by choosing to enroll their adolescents in charter schools. These findings are largely consistent with previous studies, and serve to further advance research on African American family involvement with adolescent children in urban high schools. Recommendations for future research and practices offer direction on how to recognize and support African American family involvement.Ed.D., Educational Leadership and Management -- Drexel University, 201
When Physical Activity Fails to Protect Against Weight Gain: The Relation of Weight Change to Behavioral and Psychological Processes in Active Young Adults
No full textYoung adulthood is a particularly high risk time for excess weight gain, yet factors related to weight gain prevention in this population are poorly understood. Although moderate-to-vigorous physical activity (MVPA) is a primary component of many prevention efforts, recent research suggests that it may be insufficient to protect against weight gain for many individuals, likely because other physical activity and eating-related factors also influence weight. This study aimed to examine whether key eating- and physical activity related behavioral and psychological factors were associated with weight change among young adults meeting national physical activity guidelines. Young adults (ages 21-30; N=69) in the normal weight-range who met national physical activity recommendations had their weight measured by research staff, wore an accelerometer for one week, and completed self-report and interview-based measures of their weight history and key eating- and physical activity related behavioral and psychological factors. Participants gained an average of .91 kg over the past three years and engaged in an average of 274.04 minutes/week of accelerometer-measured bouted MVPA. Higher frequency of eating out was associated with greater weight gain, such that individuals above the median for weight gain ate out 7% more often than those below the median. Calorie, fat, and added-sugar intake, as well as sedentary behavior, light activity, and unbouted MVPA were unrelated to weight change. Greater hedonic hunger, dietary disinhibition, and food cravings, and lower self-efficacy for healthy eating were related to greater weight loss in those who had lost weight over the past three years, but were unrelated to weight change in those who were weight stable or who had gained weight. This study provides a preliminary investigation into factors associated with weight gain in active young adults and suggests that eating out may be a particularly useful target for weight gain prevention efforts in this population. Future research should address some of the limitations of this study, including using a longitudinal design, objectively assessing all weights, and recruiting a larger sample.M.S., Psychology -- Drexel University, 201
Understanding the role of slurry electrode components on electrochemical performance
No full textThis thesis addresses how different components of flowable electrodes (e.g. carbon slurry) affect electrochemical performance. Due to their scalability, flowable electrode systems, such as electrochemical flow capacitors (EFCs), have attracted significant attention in recent years as a result of the increasing need for efficient and reliable grid scale energy storage, load-leveling, and deionization systems. EFCs use a flowable carbon slurry electrode that comprises of an active (charge storage) material and conductive additive material suspended in liquid electrolyte. Past literature details extensive research into electrochemical optimization of the active material of carbon slurries, but the effects of the conductive additive and electrolyte compositions are still not well understood. This work focuses on a systematic, experimental approach in a static EFC configuration to build a foundation for understanding the electrochemical properties of different conductive additives and electrolytes. Specifically, different conductive additive morphologies (0D, 1D, and 2D nanoparticles) and loadings are examined through electrochemical and rheological lenses to relate electrochemical performance (rate-dependence, slurry conductivity, efficiency) to pumping losses (viscosity). Meanwhile, different electrolyte species (varying ion valency, size, and pH) at different ionic strengths (concentrations) are investigated through electrochemical testing to determine relationships between intrinsic electrolyte parameters and ionic strength of the electrolyte relative to the overall rate-dependence, resistivity, and efficiency of the slurry. This work provides a foundation for future work regarding flowable electrode optimization by demonstrating the drastic changes that these components (conductive additives, electrolytes) can have on electrochemical performance.M.S., Mechanical Engineering and Mechanics -- Drexel University, 201