Browsing by Subject "Chemistry"

Now showing 1 - 5 of 5
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    A 24-year longitudinal study on a STEM gateway general chemistry course and the reduction of achievement disparities
    (Public Library of Science, 2025-02-26) Basu, Partha; Malik, David J.; Graunke, Steven; Chemistry and Chemical Biology, School of Science
    The "First Year Experience" is a critical component of retention of STEM majors. Often, general chemistry has been labeled as a "gatekeeper" course for STEM careers due to a high attrition rate and a course that leads to increased time for graduation when students are inadequately prepared. We demonstrate that the active learning strategy Peer-Led Team Learning (PLTL) model increases student retention (%DFW calculated from earned grades A through F plus withdrawals, W) and success (%ABC calculated from earned grades A through F). We have analyzed approximately 24 years of data in general chemistry I (~20,000 students), using Analysis of Covariance (ANCOVA), which showed progressive, significant improvement in both student success and completion metrics. A Hierarchical Linear Modeling (HLM), using a combination of course and student-level variables, demonstrated the impact of PLTL on internal exam metrics and overall course grades. Further, HLM modeling assessed the impact of PLTL controlling for various student demographics. PLTL strongly impacted URM student completion rates to a greater degree than well-represented students, reducing the URM/non-URM achievement gap.
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    Building more bonds and widening our reach: strategic expansion of chemical information skills instruction for undergraduates using the online environment
    (2021-04-08) Snajdr, Eric
    The Chemistry librarian at Indiana University-Purdue University, Indianapolis worked closely with the Department of Chemistry over many years in developing a library educational curricular plan where chemical information skills instruction was inserted into strategic points of the chemistry undergraduate degree programs. This included library instruction in various courses (first-year intro course, cornerstone, lab courses, and capstone). Prior to COVID-19, this instruction, was almost entirely provided by the librarian face-to-face. In mid 2020, the pandemic forced the transition completely to the online environment. This presented numerous challenges but led to important opportunities as well. The librarian was not only able to successfully transfer the entire curricular plan to the online environment, but the transition allowed the librarian to increase instructional involvement in places that would not have been feasible in a face-to-face setting. Additionally, during the transition to online teaching, the librarian increased the quality of specific assignments by implementing the Transparency in Learning and Teaching in Higher Education (TILT) format. This resulted in learning experiences that were clearer in purpose to the students, and more equitable for students to achieve success. The end result was a more robust curricular approach to chemical information skills instruction.
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    Chemical modification of AAV9 capsid with N-ethyl maleimide alters vector tissue tropism
    (Springer Nature, 2023-05-25) Mulcrone, Patrick L.; Lam, Anh K.; Frabutt, Dylan; Zhang, Junping; Chrzanowski, Matthew; Herzog, Roland W.; Xiao, Weidon; Pediatrics, School of Medicine
    Although more adeno-associated virus AAV-based drugs enter the clinic, vector tissue tropism remains an unresolved challenge that limits its full potential despite that the tissue tropism of naturally occurring AAV serotypes can be altered by genetic engineering capsid vie DNA shuffling, or molecular evolution. To further expand the tropism and thus potential applications of AAV vectors, we utilized an alternative approach that employs chemical modifications to covalently link small molecules to reactive exposed Lysine residues of AAV capsids. We demonstrated that AAV9 capsid modified with N-ethyl Maleimide (NEM) increased its tropism more towards murine bone marrow (osteoblast lineage) while decreased transduction of liver tissue compared to the unmodified capsid. In the bone marrow, AAV9-NEM transduced Cd31, Cd34, and Cd90 expressing cells at a higher percentage than unmodified AAV9. Moreover, AAV9-NEM localized strongly in vivo to cells lining the calcified trabecular bone and transduced primary murine osteoblasts in culture, while WT AAV9 transduced undifferentiated bone marrow stromal cells as well as osteoblasts. Our approach could provide a promising platform for expanding clinical AAV development to treat bone pathologies such as cancer and osteoporosis. Thus, chemical engineering the AAV capsid holds great potential for development of future generations of AAV vectors.
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    In-vitro evaluation of the effectiveness of polyphenols based strawberry extracts for dental bleaching
    (Springer Nature, 2023-03-13) Kohli, Shivani; Bhatia, Shekhar; Banavar, Spoorthi Ravi; Al‑Haddad, Afaf; Kandasamy, Murugesh; Bin Qasim, Syed Saad; Kit‑Kay, Mak; Pichika, Mallikarjuna Rao; Daood, Umer; Medicine, School of Medicine
    To formulate a dental bleaching agent with strawberry extract that has potent bleaching properties and antimicrobial efficacy. Enamel specimens (3 × 3 × 2 mm3) were prepared. Quaternary Ammonium Silane (CaC2 enriched) was homogenized with fresh strawberries: Group 1: supernatant strawberry (10 g) extract < Group 2: supernatant strawberry (10 g) extract + 15%HA (Hydroxyapatite) < Group 3: supernatant strawberry (10 g) extract + 15% (HA-2%k21) < Group 4: supernatant strawberry (20 g) extract only (20 g strawberries) < Group 5: supernatant strawberry (20 g) extract + 15% HA < Group 6: supernatant strawberry (20 g) extract + 15% (HA-2%K21) < Group 7: In-office Opalescence Boost 35%. Single-colony lactobacillus was examined using confocal microscopy identifying bacterial growth and inhibition in presence of bleaching agents using 300 µL aliquot of each bacterial culture. Images were analysed by illuminating with a 488 nm argon/helium laser beam. Colour difference (∆E00) was calculated using an Excel spreadsheet implementation of the CIEDE2000 colour difference formula and colour change measured between after staining and after bleaching. Scanning electron microscope was used to image specimens. Raman spectra were collected, and enamel slices were used for STEM/TEM analysis. HPLC was used for strawberry extract analysis. Nano-indentation was performed and X-ray photoelectron spectroscopy. Antioxidant activity was determined along with molecular simulation. hDPSCs were expanded for Alamar Blue Analysis and SEM. Mean colour change was significantly reduced in group 1 compared to other groups (p < 0.05). CLSM showed detrimental effects of different strawberry extracts on bioflms, especially with antimicrobial (p < 0.05). Groups 1, 2 and 3 showed flatter/irregular surfaces with condensation of anti-microbial in group 3. In strawberry specimens, bands predominate at 960 cm-1. HPLC determined the strawberry extracts content. Molecular simulation verified interaction between calcium and polyphenol components. XPS peak-fitted high-resolution corresponding results of Ca2p3/2 and Ca2p1/2 for all k21 groups. Combination of 10 g strawberry extract supernatant and 15% (hydroxyapatite 2%k21) improved the whiteness and provided additional antimicrobial potential. The novel strawberry extract and antimicrobial based dental formulation had immediate bleaching effect without promoting significant changes in enamel morphology.
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    Large-scale Top-down Proteomics Using Capillary Zone Electrophoresis Tandem Mass Spectrometry
    (MyJove Corporation, 2018-10-24) McCool, Elijah N.; Lubeckyj, Rachele; Shen, Xiaojing; Kou, Qiang; Liu, Xiaowen; Sun, Liangliang; Computer and Information Science, School of Science
    Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) has been recognized as a useful tool for top-down proteomics that aims to characterize proteoforms in complex proteomes. However, the application of CZE-MS/MS for large-scale top-down proteomics has been impeded by the low sample-loading capacity and narrow separation window of CZE. Here, a protocol is described using CZE-MS/MS with a microliter-scale sample-loading volume and a 90-min separation window for large-scale top-down proteomics. The CZE-MS/MS platform is based on a linear polyacrylamide (LPA)-coated separation capillary with extremely low electroosmotic flow, a dynamic pH-junction-based online sample concentration method with a high efficiency for protein stacking, an electro-kinetically pumped sheath flow CE-MS interface with extremely high sensitivity, and an ion trap mass spectrometer with high mass resolution and scan speed. The platform can be used for the high-resolution characterization of simple intact protein samples and the large-scale characterization of proteoforms in various complex proteomes. As an example, a highly efficient separation of a standard protein mixture and a highly sensitive detection of many impurities using the platform is demonstrated. As another example, this platform can produce over 500 proteoform and 190 protein identifications from an Escherichia coli proteome in a single CZE-MS/MS run.