• Graduate Research Conference 2015

      University of Maryland, Baltimore. Graduate Student Association (2015-03-09)
      This is the program and collection of abstracts for poster and oral presentations for the 37th Annual GRC. This conference offers researchers, be they graduate students, professional students, or postdoctoral fellows, the opportunity to present their discoveries to a diverse audience. Our unique combination of research across various professional schools and disciplines allows basic scientists, informaticists, social scientists, nurses, and policy researchers to intermingle and discuss their research in an interdisciplinary setting.
    • Exome sequencing from extreme responders to aspirin identifies a novel variant associated with platelet aggregation

      Backman, Joshua David; Ning, B.; Lou, W.; Perry, James; Shi, L.; Lewis, J.; Shuldiner, Alan R.; Yerges-Armstrong, Laura M. (2015-03-09)
      Objective: To identify novel variants that may significantly impact platelet response to aspirin and DAPT (Dual Anti-Platelet Therapy).
    • Regulators of Hematopoietic Progenitor Differentiation

      Baldeosingh, Rajkumar; Gao, Hongjuan; Wu, Xiaorong; Fossett, Nancy (2015-03-09)
      Hematopoietic stem cells (HSCs) must be capable of both self-renewal and production of progenitor cells that give rise to all of the blood cell types, the two basic principles of stem cell biology. Investigations into gene networks controlling HSC response to stress have been conducted using model organisms such as Drosophila melanogaster. One of the factors controlling vertebrate HSC multipotency and differentiation is the GATA:FOG complex. GATA:FOG complexes regulate the development of a number of blood lineages. In Drosophila, the GATA:FOG complex blocks the differentiation of hematopoietic progenitors into the stress-responsive lamellocyte lineage. Drosophila hematopoietic progenitors are strikingly similar to HSCs and are used as a model for these vertebrate stem cells. We used fly genetics to identify GATA:FOG network members that block the stress-response of hematopoietic progenitors.
    • Barriers to Providing And Receiving Adequate Services for Latinos in a New Immigrant Settlement Destination

      Goodman, Marci; Maskell, Erin; Negi, Nalini (2015-03-09)
      AIMS 1. Explore social service providers' experiences serving Latinos in the social and cultural context of Baltimore. 2. Identify service gaps in social service provision for Latino Immigrants in Baltimore BACKGROUND INFORMATION Baltimore is a new immigrant settlement destination. Latinos are the fastest rising ethnic group in Baltimore with census data indicating a doubling of the population from 11,061 in 2000 to 25,960 in 2011. While social service delivery is highly critical in the maintenance of the health of vulnerable populations, little is known about the context of social services in new immigrant settlement destinations. METHODS Social service providers who work with Latino immigrant clients were recruited using purposive theoretical sampling. In--depth qualitative interviews were then conducted and audio recorded and later transcribed. DISCUSSION AND IMPLICATIONS FOR PRACTICE Providers are stretched very thin, as few providers work with limited resources to provide support for a growing number of Latinos: Participants rely on networking and collaboration for strength; Participants report feeling a "sense of duty" to serve the Latino community. More support is needed: Recruitment, training, and retention of Spanish speakers in various health science and service oriented programs is crucial; A focus on curriculum development is needed to better prepare future providers for culturally sensitive practice with Latino immigrants. Continued outreach by Baltimore City: This will help to develop trust with the Latino immigrant community.
    • Characterization of Schu S4 delta aroD as a putative vaccine candidate against pulmonary tularemia

      Cunningham, Aimee L.; Santiago, Araceli E.; Mann, Barbara J., Ph.D.; Qin, Aiping; Grassel, Christen; Vogel, Stefanie N.; Barry, Eileen M. (2015-03-09)
      Francisella tularensis is the etiological agent of the human disease tularemia and a Tier 1 Select Agent. There is a need for an efficacious vaccine against this pathogen due to its low infectious dose, high mortality rate, and ability to be spread by aerosol. To this end, we have engineered a defined live attenuated strain derived from the highly human virulent F. tularensis WT strain Schu S4, designated Schu S4ΔaroD; this strain lacks aroD, the 3rd enzyme in the chorismate biosynthesis pathway used for synthesis of aromatic amino acids. Schu S4ΔaroD is attenuated for growth in broth cultures and in both J774 and primary murine peritoneal macrophages, with a pulmonary LD50 > 105 CFU in C57BL/6 mice (compared to WT Schu S4 LD50 < 10 CFU). Intranasal immunization with Schu S4ΔaroD protects against high-dose WT pulmonary challenge in C57BL/6 mice. A single 50 CFU dose of Schu S4ΔaroD generated 80% protection against 100 CFU challenge, and addition of a 105 CFU booster to the initial 50 CFU vaccination is 80% and 40% protective against 500 or 1000 CFU challenge, respectively. Further studies revealed that a 103 or 105 CFU priming dose followed by a 108 CFU boost is 100% protective against 1000 CFU WT Schu S4 pulmonary challenge. This level of protection has not previously been demonstrated by any tularemia vaccine candidate. Bacterial burden following i.n. vaccination found that regardless of initial dose, immunized mice show identical bacterial loads (107 CFU/g tissue in the lung and 105 CFU/g tissue in the liver) at the peak of infection. However, time to peak burden was dose-dependent, as animals receiving a higher initial inoculum (at least 5600 CFU) reach this peak at day 3, as opposed to day 7 in lower initial inoculum groups. Peak bacterial burden correlates with maximal associated histopathology in the liver and peak pro-inflammatory cytokine and chemokine production in lungs, liver, and spleen (TNF-α, IL-1β, Cox-2, KC, iNOS, MCP-1). Our study shows Schu S4ΔaroD serves as an efficacious defined live attenuated vaccine against pulmonary tularemia. We have revealed a dose-dependent response to Schu S4ΔaroD, which may help determine the protective capacity of this vaccine and assist in development of vaccine-associated correlates of protection in the mouse model.
    • Risks Factors for Colorectal Precancerous and Cancerous Lesions in HIV-infected Patients

      Yimgang, Doris; Magder, Laurence S.; Stafford, Kristen Alyce; Fisher, Lydia H.; Cullen, Nicole R.; Riedel, David J.; Kang, Minji; Innis, Ellen K.; Wang, Elizabeth W.; Riner, Andrea N.; et al. (2015-03-09)
      Although data are conflicting, some studies suggest that HIV-infected patients may have a higher risk for colorectal cancer. The purpose of this study is to analyze the relationship between known and potential HIV specific risk factors on the incidence of precancerous and cancerous lesions found on colonoscopy in HIV-infected individuals. This is a retrospective analysis of clinical data collected on 263 HIV-infected patients.
    • The Role of Residential Segregation in Disparity Research: A Case Example of ADHD Diagnosis and Treatment

      Pennap, Dinci; Burcu, Mehmet; Safer, Daniel J.; Zito, Julie Magno (2015-08-24)
    • Health Insurance Status and Unmet Medical Needs Among Injured Children: A Population-Based Study

      Alqahtani, Faisal, M.D., M.P.H.; Pennap, Dinci; Alghnam, Suliman, Ph.D. (2015-10)
    • Developing a 3D-Printed Peri-Implantium Based Plaque Assay (2016)

      Feldman, Steven G.; Kim, Jeffrey J. (2016-03-23)
      Objectives: Currently, there is no consensus of how to best maintain dental implants. With over 2 million dental implants placed annually, there is an urgent need for objective ways to measure plaque removal from peri-implant surfaces. Here, we developed a cost effective, fast and accurate way to measure the effectiveness of various oral hygiene products to maintain health of the implant and surrounding oral tissues using a 3D printer. Methods: Digitizations of dentoform teeth and jaws provided the basis for 3D-printed custom models. Simulated gingiva and genuine dental implants were incorporated to maximize clinical relevance. Fabricated model teeth were analyzed for consistency of cusp heights, inter-cusp distance and mass. Mass was remeasured following water immersion. An artificial plaque substrate (APS) was applied to 3D-printed and porcelain surfaces to ensure consistent performance. A standard by which toothbrush mediated APS removal from the interproximal and subgingival areas was developed, with varying brushing angle, force and toothbrush design. Results: The 3D-printed models had higher dimensional accuracy than the resolution of the 3D printer (X/Y<400μm, Z<100μm). Immersion in water yielded an increase in mass that was correlated linearly with time (r2 = .9365) and could be reversed upon desiccation. APS behaved similarly on the 3D-printed surface as porcelain. Conclusions: Lack of commercially available dentoforms with accurate dental implant anatomy limited the ability to simulate implant systems in vitro. However, the advent of low-priced commercial grade 3D printers enables individuals to create such models rapidly and at low cost. We developed highly accurate, anatomically correct, 3D-printed dental implant model systems, which mitigated flaws in extant designs and devised a high-throughput method for assessing in vitro plaque removal that is superior to existing methods. In the future, digital model files can be included in an electronic library for rapid manufacturing of identical models anywhere in the world.
    • Graduate Research Conference 2016

      University of Maryland, Baltimore. Graduate Student Association (2016-03-23)
    • The Effects of reactive and voluntary step training on balance recovery during lateral perturbation in individuals with chronic stroke

      Yang, Chieh-ling; Gray, Vicki L.; McCombe-Waller, Sandra; Rogers, Mark William (2016-04)
      Falls have been reported as high as 73% in community dwelling individuals following a stroke. Many falls happen while transferring weight laterally. To guard against loss of balance with this lateral weight transfer a reactive, protective step is commonly used to recover balance. Current rehabilitation practices mainly focus on intentional voluntary actions to improve balance control which may not carry-over to the development of protective stepping strategies to avoid a fall. Objective: The purpose of this study is to determine the effects of six weeks of reactive versus voluntary step training on balance recovery during lateral perturbations in individuals with chronic stroke
    • Graduate Research Conference 2017

      University of Maryland, Baltimore. Graduate Student Association (2017-04-03)
    • Graduate Research Conference 2018

      University of Maryland, Baltimore. Graduate Student Association (2018-03-15)
    • ADHD Coaching Communication Modalities: An Exploratory Mixed Methods Study

      Ahmann, Elizabeth; Saviet, Micah (2019)
      Background. Telephone is the most frequently used communication modality for coaching sessions in the U.S.; a combination of in-person and telephone coaching is also common. Coaching in person or by telephone, videoconference, or a combination of methods demonstrates positive outcomes. Studies comparing outcomes of coaching inperson with telephone or videoconference suggest varied results. To date, no study has specifically examined communication modalities in coaching for individuals having attention deficit hyperactivity disorder (ADHD). Purpose. This mixed methods exploratory study: • Reviews extant literature on ADHD coaching outcomes to identify coaching modalities used • Surveys ADHD coaches to explore (a) the frequency of use and perceived efficacy of varied modalities and (b) coaches' views of benefits and drawbacks of each
    • Graduate Research Conference 2019

      University of Maryland, Baltimore. Graduate Student Association (2019-03-15)
    • Designing Specific Inhibitors to Target S100B in Melanoma

      Vera-Rodriguez, Darex J.; Young, Brianna; Spriggs, Shardell; Yu, Wenbo; Wilder, Paul T.; MacKerell, Alexander D., Jr.; Weber, David J., Ph.D. (2020)
      Malignant melanoma (MM) is defined as the most dangerous form of skin cancer, causing a large majority of skin cancer deaths. Previous studies demonstrate S100B as a tumor marker in MM, a protein that interacts with the tumor suppressor p53, inhibiting p53 function. With the goal of blocking this interaction, three binding sites on S100B for small molecules have been identified. However, developing drugs specific for S100B over other S100-family members remains a challenge. This project aims to identify S100B-specific small molecule inhibitors and understand the basis of their specificity over other S100 family members, specifically S100A1. A 2D-[1H,15N] NMR HSQC of S100B bound to a non-specific fragment showed multiple chemical shifts perturbations (CSPs) including residues A9, L10, F43, L40, F73, and C84. Interestingly, fewer and less pronounced CSPs were observed for a S100B-specific fragment. Site-Identified Ligand Competitive Saturation (SILCS) molecular dynamics (MD) simulations were performed to determine potential S100B binding sites that could explain the CSPs. Results show a strong hydrophobic pocket at low Grid Free Energy (GFE) levels comprised by the residues that showed CSPs for compounds that bind S100B. FDA-approved compounds were tested using SILCS-Monte Carlo (MC) to determine ligand binding poses at this pocket. Specific compounds were targeted with strong hydrophobic interactions and hydrogen bonds at low Ligand GFE (GFE). These data provide important information relevant to developing S100B-specific drugs to treat MM.
    • Development of the Drude Polarizable Force Field for Small Molecules Drude General Force Field (DGenff)

      Chatterjee, Payal; MacKerell, Alexander D., Jr. (2020)
      The classical Drude oscillator polarizable force field offers an explicit treatment of induced electronic polarization presently not addressed in the commonly used additive force fields. Such an empirical approach leads to an improved and more accurate representation of electrostatic interactions in Molecular Mechanics and Molecular Dynamics (MD) simulations. The Drude Polarizable Force Field presently include topologies and parameters for biomolecules such as proteins, lipids, carbohydrates, and nucleic acids along with a limited set of small molecules. The present research is an effort to expand the existing Drude-oscillator based polarizable force field of CHARMM for general small drug like molecules – Drude General Force Field (DGenFF). A thorough development of such a force field will allow users to use polarizable force fields for drug design and other chemical fields.