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Trait Mindfulness, Social Problem-solving, and Post-trauma Symptoms
No full textA sizeable portion of the population has experienced at least one potentially traumatic event in their lifetime. In the U.S., researchers have found that 89.7% of a representative sample had experienced at least one lifetime trauma (Kilpatrick et al., 2013). While some individuals may be resilient, it is possible for one to develop post-trauma symptoms (PTS) in the wake of such events. In psychological research, as mindfulness theories have gained more attention, a significant connection between mindfulness and PTS has been observed. Mindfulness-based treatments have also amassed empirical support for successfully alleviating PTS (Vujanovic, Niles, & Abrams, 2016). Social problem-solving (SPS), a process whereby an individual identifies and overcomes barriers to goals, is a small but growing body of research concerning PTS. Lack of problem-solving construct definition consistency, mixed results of problem-solving inspired therapeutic outcomes, and a general dearth of correlational studies warrant further research investigating SPS and PTS. SPS and mindfulness share conceptual similarities, but investigating their differential associations with PTS is necessary, as both show promise in providing alternative theories relating to, and interventions for, PTSD and similar disorders. The current study recruited participants using Amazon Mechanical Turk, a crowdsourcing tool with which participants were able to remotely complete self-report measures of demographic information, the Social Problem-Solving Inventory: Revised – Short Form (SPSI:R-S), the Five Facet Mindfulness Questionnaire (FFMQ-15), the Life Events Checklist (LEC-5), and PTSD Checklist for the DSM-5 (PCL-5). Using data collected from these self-report measures, the current study demonstrated that scores of trait mindfulness and PTS are correlated, SPS and PTS are correlated, and trait mindfulness and SPS are correlated through Pearson product-moment correlations. The present study also utilized hierarchical regression modeling to demonstrate that trait mindfulness predicted PTS severity, SPS predicted PTS severity, and SPS adds to the predictive ability of trait mindfulness on PTS severity above what was achieved by trait mindfulness alone. Results show that trait mindfulness and social problem-solving subscales predict unique variance in PTS severity in trauma-exposed individuals. Future studies are necessary to uncover more about the relationship between specific symptom clusters of PTSD symptoms, specific social problem-solving domains, and individual facets of trait mindfulness. Results from the current study my help to contribute to developing more integrated and comprehensive intervention strategies aimed at treating individuals suffering from PTS.M.S., Psychology -- Drexel University, 201
Synthesis and Characterization of the MAB Phases: Ternary, Nanolayered Transition Metal Borides
No full textThe MAB phases are atomically laminated, ternary transition metal borides whose crystal structures are comprised of stacked M-B layers (M = transition metal) interleaved by monolayers of Al or Zn, or bilayers of Al atoms. This name stems from the fact that their nanolaminated atomic structures resemble the nanolaminated MAX phases. Structurally, the MAB phases are highly anisotropic because the M-B layers contain parallel, covalently bonded B-B chains and the M-B layers themselves are separated by relatively weaker M-Al bonds. Though nearly all the MAB phase compounds were discovered prior to the 1990s, their properties had remained largely unknown, in part, because of the unavailability of bulk, high purity, polycrystalline samples. In this thesis, three MAB phases are synthesized as high-purity, fully dense ceramics and five as powders using reactive powder metallurgy with the goal of systematically characterizing their fundamental physical properties. Some of these compounds were synthesized in bulk for the first time, while many of these properties were never characterized for polycrystalline samples. The MAB phases MoAlB, Mn2AlB2, and Fe2AlB2, like their binary boride counterparts, are found to be good conductors of electricity (0.3-5 m) and highly dependent on the transition metal. From low-temperature heat capacity studies, the high conductivities are found to be related to high densities of states at the Fermi level. In turn, the high electrical conductivity of MoAlB translates to good thermal conductivities (28 Wm-1K-1 at room temperature), wherein a majority of the heat is transported by electrons. In terms of mechanical properties, the Young's and shear moduli ranged from 250-370 GPa and 100-150 GPa, respectively, and showed a weak temperature dependence up to 1000 oC. Among these three MAB phases, the hardness ranged between 8-11 GPa, and illustrate that they are significantly lower than the 16-23 GPa range found for the corresponding MoB, MnB, and FeB compounds. From an in-depth study of the oxidation resistance of MoAlB in ambient air, it was clear that it is the first transition metal compound to be highly oxidation resistant in air and performs comparably to state-of-the-art alumina-forming alloys and compounds. Because the unidirectional B-B chains and the face-sharing BM6 trigonal prism building blocks in the MAB phases are also characteristic of the binary transition metal monoborides, this work endeavored to gain insights on how the Al layers distinguish these two families of solids. The relatively weakly bonded nature of the Al layers was evidenced in several ways: (1) the thermal decomposition of the MAB phases into the corresponding MB phase and elemental Al at high temperatures, (2) the formation of protective aluminum oxide scales on MoAlB when heated in ambient air to high temperatures, (3) considerably lower Vickers hardness and elastic moduli than the corresponding binary borides, and (4) the occurrence of intralayer delamination during indentation. However, there are similarities between the two as well. Both the binary monoborides and MAB phases of the 3d transition metals were found to have their lowest thermal expansion coefficients parallel to the B-B chains, which reflects the high strength of the covalent B-B bonds. Moreover, the insertion of Al into CrB and Cr3B4, to form Cr2AlB2 and Cr3AlB4, respectively, did not alter the magnetic ground state from paramagnetism.Ph.D., Materials Science and Engineering -- Drexel University, 201
Designing a novel immunomodulatory surface modification to promote biomaterial-tissue integration
No full textThe foreign body response (FBR) to implanted biomaterials provides a major challenge for successful biomaterial-tissue integration in the body. During the FBR, biomaterials are encapsulated in a collagenous, scar-like capsule that prevents the material from interacting with the surrounding tissue. Ultimately, the biomaterial will fail due to degradation and encapsulation, resulting in the removal and replacement of the implant. The primary culprit of the FBR is macrophages, the primary cell type of the inflammatory response. Macrophages exist on a spectrum of behaviors, typically transitioning from an "M1" pro-inflammatory to "M2" pro-healing phenotype in healthy wound healing. The M2 phenotype can be further broken down into interleukin-4 (IL4) stimulated "M2a" and IL10 stimulated "M2c" macrophages, although the differences between these phenotypes in biomaterial-tissue integration have not been fully elucidated. During the FBR, this phenotypic transition is halted, and macrophages exhibit chronic M1 behavior leading to fibrous capsule formation. While many biomaterial strategies to inhibit chronic M1 behavior and promote the natural M1-to-M2 phenotype switch have been investigated, there is currently no method to inhibit the FBR. Furthermore, methods to temporally control macrophage behavior to prevent chronic responses in either direction have not been successfully implemented. Therefore, the overarching goals of this work were to (1) design an affinity-based cytokine release system to modulate macrophage phenotype over time and (2) test the ability of the drug delivery system using biotin-avidin to temporally modulate macrophage phenotype both in vitro and in vivo. First, an investigation into the M2c phenotype revealed that this phenotype may act at early stages of wound healing, primarily contributing to matrix remodeling. M2c macrophages were found to secrete high quantities of matrix degrading enzymes suggesting that this phenotype may not be beneficial in biomaterial-tissue integration. Comparatively, M2a macrophages have been previously shown to inhibit fibrous capsule formation and promote angiogenesis in the context of biomaterial-tissue integration. Therefore, the M2a polarizing cytokine IL4 was bound to Gelfoam scaffolds, used as a model biomaterial throughout, via the biotin-avidin affinity conjugation system. The biotin avidin system has been previously shown to release proteins over time and has the potential for creating a loadable protein drug delivery system in vitro. However, the ability to modulate macrophage activation by controlling the parameters of the system over time have not been thoroughly investigated. The effects of modulating both the fold molar excess of biotin on the scaffold surface and altering the avidin variants were investigated. Increasing the fold molar excess (FME) of biotin on the scaffold conjugated with CaptAvidin, and not Streptavidin, was shown to decrease IL4 release over time. Additionally, in a similar manner, increasing the FME of biotin on the scaffold with CaptAvidin and IL4 decreased M2a activation in vitro. Scaffolds with low levels of biotinylation in vivo were shown to have the highest reduction in fibrous capsule formation compared to groups with no IL4, adsorbed IL4 or a high degree of biotinylation. However, differences in gene expression signatures of explants were minimal. A more thorough investigation is required to determine the in vivo effects of modified scaffolds on fibrosis and angiogenesis. Overall, modifying scaffolds with biotin-avidin shows great potential in designing immunomodulatory drug delivery systems to control macrophage activation over time. Future studies should focus on utilizing the biotin-avidin system as a loadable cytokine release system to control the M1-to-M2 phenotypic transition which would have significant impact on treating pathologies where this transition is halted, like fibrosis and chronic wounds.Ph.D., Biomedical Engineering -- Drexel University, 201
Urban High School Educators' Perceptions of the Effects of Trauma on Students Identified with Disabilities that Require Learning Support: A Grounded Theory Study
No full textThe effects of complex trauma on students diagnosed with disabilities from low socioeconomic urban schools have become increasingly recognized as a serious issue involving students' academic and behavioral performance. Research is lacking at the educator level for what the perceived effects are on these students and how they may be better served with supports additional to special education learning supports. The specific purpose of this grounded theory study was to explore the perspectives of urban educators on the academic and behavioral challenges of students diagnosed with disabilities who receive learning support. Of particular interest was whether these deficits may indicate a prevalence of symptomology associated with complex trauma, and if the diagnosis of learning disability or related diagnosis provides these students with adequate supports to meet their academic and social-emotional needs. The ultimate study goal was to use grounded theory to generate a substantive theory from the data collected and analyzed. For this study, 14 urban special educators as well as the school psychologist, a counselor, the climate manager, and the school dean were interviewed and subsequent data were collected and analyzed. The key assertion derived from the data was that the majority of urban students diagnosed with disabilities requiring learning support are suffering from multiple traumatic experiences that require additional mental health supports. As reported by the educators in this study, these students have learning, attention, memory, and behavioral problems that are seriously impeding their academic progress and socioemotional development. All the educators interviewed in this study recommended additional, school-based mental health supports to help mitigate these problems.Ed.D., Educational Leadership and Management -- Drexel University, 201
Exploring the Impact of Comprehensive Civic Engagement on Adolescent Growth: A Qualitative Case Study
No full textAdolescence, which begins with the onset of puberty and ends with social and economic independence, is a critical time in identity formation. The purpose of this qualitative case study was to explore the impact of the experience gained from participation in a year-long comprehensive civic engagement program on the conscientization of the adolescent and its impact on their identity development, their self-knowledge and their civic responsibility. While there is increasing research on the positive impact of civic engagement programs on high school and college level students, research was needed specifically on civic engagement programs within middle school to assess whether they have a similar impact on younger adolescents. This study examined the impact of the Tzedek Program, a comprehensive civic engagement program for seventh graders, on its alumni one year, two years and three years after completion. The research was guided by the following central question: What is the impact of a year-long comprehensive civic engagement program on the identity development of the adolescent? And its sub-questions: (1) How do adolescent participants in a year-long comprehensive civic engagement program in an independent day school describe the essence of their experiences? (2) How do the alumni adolescent participants from a year-long comprehensive civic engagement program in an independent day school describe their ongoing interest in or commitment to community engagement? (3) How do parents of alumni adolescent participants from a year-long comprehensive civic engagement program in an independent day school describe their child's ongoing interest in or commitment to community engagement? Results of this study suggest grassroots civic engagement both within the classroom and within the community at large help adolescents to learn more about themselves, and to feel more connected to their larger community and to their peers who undergo the civic engagement with them. This study also suggests adolescents who undergo civic engagement feel a sense of gratitude, are empowered to become change-makers, and continue serving their community in the future. Further research needs to be conducted to see if the long-term impact of the Tzedek Program continues into the second half of high school and beyond.Ed.D., Educational Leadership and Management -- Drexel University, 201
The role of evaporation and particle self-assembly on deposition morphologies of inkjet-printed drops
No full textInkjet printing is a powerful tool in various applications from printable electronics to biomaterials due to its low-cost, compatibility with a wide range of ink materials, and accurate deposition of droplets in the micron diameter range. In this work, the dynamics of the contact line and deposition of inkjet-printed drops are investigated to develop the fundamental understandings of the transport phenomena and improve inkjet printing techniques by controlling final deposition morphologies. Compared to their spherical counterparts, ellipsoidal particles experience stronger adsorption energy to the drop surface where the anisotropy-induced deformation of the liquid-air interface leads to much greater capillary attractions between particles. Using inkjet-printed colloidal drops of varying drop size, particle concentration, and particle aspect ratio, we demonstrate how the suppression of the coffee-ring is not only a function of the particle anisotropy, but rather a competition between the propensity for particles to assemble at the drop surface via capillary interactions and the evaporation-driven particle motion to the contact line. When the capillary force / the hydrodynamic force >1, ellipsoids on the drop surface form a coherent network inhibiting their migration to the drop contact line and the coffee-ring effect is suppressed, whereas when the capillary force / the hydrodynamic force <1, the ellipsoids move to the contact line resulting in coffee-ring deposition. Moreover, contact line dynamics is crucial in determining the deposition patterns of evaporating colloidal droplets. Using high-speed interferometry, we directly observe the stick-slip motion of the contact line in situ and are able to resolve the instantaneous shape of the inkjet-printed, evaporating pico-liter drops containing nanoparticles of varying wettability. The results show that the stick-slip motion of the contact line is a strong function of the particle wettability. While the stick-slip motion is observed for nanoparticles that are less hydrophilic (i.e., particle contact angle θ ≈ 74° at the water-air interface) which results in a multi-ring deposition, a continuous receding of the contact line is observed for more hydrophilic nanoparticles (i.e., θ ≈ 34°) which leaves a single-ring pattern. A three-fold increase in the number of particles required to pinning is predicted from our model when the particle wettability increases from the wetting angle of θ ≈ 74° to θ ≈ 34°. This finding explains why particles with greater wettability form a single-ring pattern and those with lower wettability form a multi-ring pattern. Finally, due to the instantaneous change in viscosity and surface tension of an evaporating biopolymer ink, solvent evaporation and polymer deposition dynamics of biopolymer drops are complex and not well understood. Using high-speed interferometry, we directly observe in real time the instantaneous drop shape of inkjet-printed pico-liter gelatin carboxyl drops containing glycerol and water. Stagnation zone due to accumulation of gelatin and glycerol driven by the evaporation-driven outward flow and surface tension-driven Marangoni flow dictates the final deposition of bi-solvent polymer droplets from a spherical cap to a volcano shape during evaporation. The results reveal new insight into the complex role surfactant plays during polymer drop evaporation and deposition processes.Ph.D., Mechanical Engineering and Mechanics -- Drexel University, 201
The Relationship Between Perceived Stress, Personality, and Performance in Professional Soccer Players
No full textThe purpose of this study was to investigate the relationships between stress, performance, and personality variables (conscientiousness and neuroticism) in professional athletes. Data from a first division professional soccer team in Brazil were used for the purposes of this study. Game performance was measured by Instat Index (Instat). Stress was measured by the Perceived Stress Scale, a scale given to players after every game in the league. Personality factors were measured by the NEO-Five Factor Inventory-Revised. A positive relationship between stress and performance was observed. Neither conscientiousness nor neuroticism mediated that relationship. Post-hoc exploratory analyses revealed significant relationships between other personality factors (extraversion, openness to experience, and neuroticism) and stress scores.M.S., Psychology -- Drexel University, 201
Behavioral and biochemical studies of novel allosteric modulators of the dopamine transporter with therapeutic potential
No full textCocaine is a highly abused drug used recreationally for social purposes. The intense sensation of euphoria induced by cocaine is the root cause of its high abuse potential. Cocaine inhibits the dopamine transporter (DAT), a membrane bound protein responsible for the clearance of dopamine (DA) neurotransmitter from the synaptic cleft. Cocaine binding to the DAT blocks DA reuptake leading to an increase extracellular DA concentration, resulting in enhanced neurotransmission causing euphoria. Currently, there are no Food and Drug Administration approved treatments for cocaine abuse and addiction. Many attempts have been made to prevent the cocaine-DAT interaction, but have largely failed due to lack of efficacy, leading to an urgent need for clinically efficacious therapeutics to treat cocaine addiction. Previously, our lab found that psychostimulants such as cocaine and amphetamines have low affinity towards the monoamine transporters (SmMATs) of the parasite, Schistosoma mansoni as compared to the human MATs (hMAT) even though both transport their respective neurotransmitters with equal or comparable efficacies. By comparing the structure of SmMATs to the hMATs, secondary allosteric sites were discovered in the human serotonin transporter (hSERT) and subsequently in the human DAT. A database of several molecules was virtually screened for binding to this site, resulting in KM822 as one of the hits which showed promising results in reducing the effects of cocaine in preliminary in vitro experiments. To improve solubility and other drug-like properties, a series of analogs of KM822 were synthesized including NP-1-152. Our current study focuses on the pharmacological characterization of NP-1-152 and to test if this compound has therapeutic potential for the treatment of cocaine addiction. We employed biochemical experiments such as substituted cysteine accessibility method (SCAM) to explore the binding site of KM822 and NP-1-152, and compared the results with two known DAT inhibitors, Modafinil and Sydnocarb. In addition, two behavior models were used to assess NP-1-152’s effect on cocaine-induced behaviors like hyperactivity and reward association in Long Evans male rats: locomotor behavior paradigm and conditioned placed preference. We found that NP-1-152 decreased cocaine-induced locomotion which was dose and time dependent. During the active wake-cycle period, NP-1-152 alone decreased locomotion at varying doses suggesting off-target effects. NP-1-152 alone did not promote place preference but did significantly decrease cocaine conditioned place preference. Modeling of this novel allosteric site using NP-1-152 might suggest a viable mechanism for the prevention and treatment of cocaine addiction.M.S., Pharmacology and Physiology -- Drexel University, 201
Exploring the Relationship of Rape Myth Acceptance with Psychopathy and Gender
No full textSexual assault has become a highly discussed topic in recent years, especially in the wake of social phenomena such as the #MeToo movement. This study seeks to explore and discuss the role that psychopathic personality traits, gender, and the manner of presentation for the sexual assault has on the perception of that assault. 432 participants across the continental United States were recruited via Amazon Mechanical Turk to take a survey through Qualtrics. This survey contained two self-report measures: The Levenson Self-Report Psychopathy Scale (LSRP), and the Illinois Rape Myth Acceptance Scale (IRMA). The IRMA was given after the participant read a vignette describing a sexual assault, and was modified to ask specific questions regarding said assault. The each participant received one vignette at random, differing on the gender of the victim (Male/Female), the gender of the assailant (male/female), and the severity of the description (Low/High). Results found significant correlation between LSRP scores and IRMA scores, but no significant main or interaction effects from either gender manipulation or the severity manipulation. Interpretations and possible follow-up studies are discussed.M.S., Psychology -- Drexel University, 201
Development of Deformity Specific Finite Element Models for Surgical Simulation of Anterior Vertebral Body Tether for Treating Scoliosis in Pediatric Subjects
No full textAdolescent Idiopathic Scoliosis (AIS) is a three - dimensional (3D) deformity which is characterized by lateral bending and axial rotation of the spine. Severe cases of AIS deformity (Cobb angle>45°) undergo surgical intervention. Recently growth friendly interventions for skeletally immature AIS subjects have shown promising results. Anterior Vertebral Body Tethering (AVBT) is one such growth friendly intervention that provides 3D correction of the deformity along with restoration of range of motion (ROM) of the spine. However, various parameters affect the outcome of this surgery, such as curve location, number of screws and amount of tether tension. Therefore, the objective of this study was to develop and validate a 10-year-old normative pediatric thoracic and lumbar spine Finite Element (FE) model with pelvis that can be used to create deformity-specific AIS FE models to simulate and optimize surgical intervention using AVBT. Chest and abdominal Computed Tomography (CT) scans were used to create a normative 10-year-old thoracic and lumbar spine FE model with pelvis with age-, and level-appropriate material properties for vertebrae, intervertebral discs and spinal ligaments. This normative FE model was morphed to a 16-year-old Lenke 1AN deformity-specific AIS FE model using dual kriging and used to simulate AVBT surgeries. A total of 48 AVBT simulations were performed with various parametric combinations of number of instrumented levels (2: all and alternate), screw placement (2: lateral and anterior-lateral), applied force levels (3: all, ends only, and apex±1) and tether force (4: 100, 200, 300 and 400 N). Clinical parameters of interest such as Cobb angle, thoracic kyphosis, lumbar lordosis and axial vertebral rotation were computed, and optimal parameter combinations for surgical planning were identified. Such FE models could serve as valuable preoperative clinical tools to aid in patient-specific surgical planning and interventional prognosis for AIS spine deformity treatment along with the potential to optimize surgical parameters and reduce surgery times, and thereby minimize the risk to pediatric patients.M.S., Biomedical Engineering -- Drexel University, 201