Macromolecular Substances Commons^™

Robert, Powers; Unl Chemistry; Nmr-Assisted Drug Discovery, Mark Griep, Robert Powers

UNL ORCA Interview Series

Dr. Robert Powers became a chemistry professor at the University of Nebraska-Lincoln in 2003 and is about to retire after 23 years. Prior to UNL, Bob was a drug discovery researcher for 11 years at American Cyanamid, which eventually became Wyeth and is now part of Pfizer. Bob was born in Jersey City, New Jersey. Something in his youth must have sparked an interest in chemistry because he earned a bachelor's in that subject from Rutgers University in New Brunswick. Then he traveled 1200 miles west to Purdue University in Indiana where he earned his doctorate. Next, he did postdoctoral …

Turning Zwitterions Into Toughening Agents: Salt-Activated Microdomains In Poly(Vinyl Alcohol) Double-Network Hydrogels, Louis D. Zhang, Jintao Yang, Si Yu Zheng

University Research

Zwitterionic hydrogels, although highly biocompatible, are widely regarded as mechanically fragile, with typical tensile strengths below 0.1 MPa, which restricts their use in load-bearing applications. Here, we address this limitation by integrating a polyzwitterionic network with a poly(vinyl alcohol) (PVA) network through high-speed pregelation agitation that enhances chain entanglement and induces flow orientation. By exploiting the salt-driven conformational transition of zwitterionic chains, a controlled salting-out step generates uniformly dispersed nanoscale microdomains that act as reversible energy-dissipating units. At the same time, balanced hydrogen bonding between the two networks moderates PVA crystallinity, limiting embrittlement while preserving elasticity. The resulting double-network hydrogel …

Exploring The Theoretical Foundation With Rupture And Delayed Rupture Experiments, Shi-Qing Wang, Junpeng Wang, Asal Y. Siavoshani, Cheng Liang

University Research

We carry out uniaxial continuous and step stretching of various cross-linked polymer networks to demonstrate how characteristics of rupture during continuous stretching and delayed rupture after step stretching can be used to probe the structure of the emergent kinetic activation theory of bond dissociation (KATBD) for elastomeric failure. Based on delayed rupture experiments, we show that the network lifetime tntw, taken as the incubation time tdel-rupt for delayed rupture, depends on temperature in an Arrhenius like manner and is exponentially sensitive to the degree of network stretching (depicted by the step-stretch ratio λss). Rupture at λb during continuous stretching for …

Nitroarene-Mediated Photo-Oxidative Deconstruction And Upcycling Of Unsaturated Rubber Waste, Junpeng Wang, Zefeng Wang, Roberto Obergon, Obed Fernando

University Research

Transforming waste polymers into materials with improved properties offers a compelling strategy for advancing the sustainable use of polymers, echoing the Chinese proverb: “Blue comes from indigo but surpasses it in blueness.” Herein, we report a photo-oxidative deconstruction and upcycling method for unsaturated rubber waste. Under 390 nm LED irradiation at room temperature, in the presence of a nitroarene oxidant, diverse unsaturated polymers─including natural rubber, polybutadiene, nitrile rubber, styrene–butadiene rubber, and even cross-linked nitrile gloves─are selectively converted into carbonyl-terminated oligomers. The aldehyde-functionalized products are cross-linked via dynamic imine chemistry with p-phenylenediamine to yield reprocessable elastomers with markedly improved tensile strength …

Exploring Anticholinergic Neurotoxicity: Diphenhydramine's Impact On Neuro-2a Cell Morphology, Expression, And Viability, Jordan B. Mcintyre

Honors Undergraduate Theses

Anticholinergic medications, such as diphenhydramine (commonly known as Benadryl), are increasingly recognized for their association with cognitive impairment and neurodegenerative disease. These medications, which inhibit the action of acetylcholine, a neurotransmitter essential for the formation and utilization of the central and peripheral nervous system, have been implicated in conditions such as dementia and may impact fundamental cellular processes like neurogenesis and cell proliferation. This study investigates the effects of diphenhydramine on neurogenesis when introduced to Neuro-2a cells during differentiation. For all studies cells were plated on coverslips or in 6-well plates with differentiation media containing 0 ng/mL, 50 ng/mL, …

Scalable Biosynthesis And Recovery Of Poly-3-Hydroxybutyrate Produced From Cotton-Derived Glucose By Cupriavidus Necator, Ashley M. Clark, Lucia E. Gargano, Gabriella M. Fioravanti, Hannah M. Schapiro, Ron G. Kander

School of Design and Engineering Papers

To combat the growing issue of petroleum plastic waste, alternative bio-based polymers are being developed. Many of these biopolymers are made from bio-derived materials, or are biodegradable, but the most promising polymers fall in both categories. Polyhydroxyalkanoates (PHAs) are one such class of polymers, and poly-3-hydroxybutyrate (P3HB), the most popular PHA, has shown great potential. This study utilized two types of cotton-derived glucose, alongside commercial glucose, as a feedstock for the biosynthesis of P3HB by Cupriavidus necator (also known as Ralstonia eutropha). The fermentation took place in a 2-L bioreactor, showing potential for scale-up. A single-solvent extraction method was …

Engineering Cxcr2-Ligand-Based Fusion Proteins To Modulate Myeloid Cell Trafficking In Pancreatic Cancer, Benjamin N. Christopher

MUSC Theses and Dissertations

Pancreatic ductal adenocarcinoma (PDAC) has one of the lowest 5-year survival rates of all cancers, and limited treatment options exist. Immunotherapy is effective in some cancer types, but the immunosuppressive tumor microenvironment (TME) of PDAC is a barrier to effective immunotherapy. CXCR2+ myeloid-derived suppressor cells (MDSCs) are abundant in PDAC tumors in humans and in mouse models. MDSCs suppress effector cell function, making them attractive targets for restoring anti-tumor immunity. The studies outlined in this dissertation (1) link tumor-intrinsic oncogenic signaling to dysregulated myeloid activity in PDAC, (2) describe a rationally designed fusion protein and potent inhibitor of CXCR2+ myeloid …

Detecting Early Changes In Cartilage Collagen And Proteoglycans Distribution Gradients In Mice Harboring The R992c Collagen Ii Mutant Using 2d Correlation Infrared Spectroscopy, Jolanta Fertala, Andrzej Steplewski, Andrzej Fertala

Department of Orthopaedic Surgery Faculty Papers

Collagen II is a vital structural component in developing bones and mature cartilage. Muta- tions in this protein cause spondyloepiphyseal dysplasia, a disease characterized primarily by altered skeletal growth and manifesting with a range of phenotypes, from lethal to mild. This study examined transgenic mice harboring the R992C (p.R1124C) substitution in colla- gen II. Previous research demonstrated significant growth abnormalities and disorganized growth plate structure in these mice, and histological signs of osteoarthritic changes in the knee joints of 9-month-old mice with the R992C mutation. Our study focuses on detecting early structural changes in the articular cartilage that occur before …

Computationally Assessing The Specificity Of Receptor Tyrosine Kinase Inhibitors, Htoo Say

Theses/Capstones/Creative Projects

Receptor tyrosine kinases (RTKs) are vital to cell signaling processes such as growth, survival, and differentiation. Dysregulation through mutation or overexpression often contributes to cancer, making RTKs key therapeutic targets for tyrosine kinase inhibitors (TKIs). However, the low specificity of many TKIs leads to off-target effects. This project uses molecular docking to evaluate the binding affinities and selectivity of FDA-approved TKIs across 18 RTK subtypes. The dockings conducted revealed significant variability in binding affinities, with Sorafenib exhibiting strong specificity for EphB2 (-7.6 kcal/mol) and poor compatibility with EphA7 and ErbB4 (-3.0 kcal/mol). These findings underscore the role of specific molecular …

Bilateral Carotid Body Paragangliomas With Succinate Dehydrogenase Complex Subunit D Gene Mutation, Abdul R. Khan, Kelvin Li, Neel D. Gupta, Jagan D. Gupta, Mohammed M. Ansari, Triet M. Do, Enrique Palacios

School of Medicine Faculty Publications

No abstract provided.

Synthesis Of Photocleavable Molecules For Neurological Applications, Nishal Madujith Egodawaththa Arachchilage Don

Theses and Dissertations

In recent biomedical research, the precise control of molecular dynamics through light activation has emerged as a powerful tool, particularly in the field of neurobiology. This approach involves the use of photocleavable cages or photoprotective groups (PPGs) that are chemically tethered to biologically active molecules such as neurotransmitters or calcium chelators. These cages remain inert until exposed to specific wavelengths of light, typically in the visible range, triggering the release of the active compound with high spatiotemporal precision.

For neurotransmitter systems, such as glutamate (Glu), which plays a critical role in synaptic transmission and memory formation, researchers have developed novel …

Molecular Architecture Of Chitin And Chitosan-Dominated Cell Walls In Zygomycetous Fungal Pathogens By Solid-State Nmr, Qinghui Cheng, Malitha C. Dickwella Widanage, Jayasubba Reddy Yarava, Ankur Ankur, Jean Paul Latgé, Ping Wang, Tuo Wang

School of Medicine Faculty Publications

Zygomycetous fungal infections pose an emerging medical threat among individuals with compromised immunity and metabolic abnormalities. Our pathophysiological understanding of these infections, particularly the role of fungal cell walls in growth and immune response, remains limited. Here we conducted multidimensional solid-state NMR analysis to examine cell walls in five Mucorales species, including key mucormycosis causative agents like Rhizopus and Mucor species. We show that the rigid core of the cell wall primarily comprises highly polymorphic chitin and chitosan, with minimal quantities of β-glucans linked to a specific chitin subtype. Chitosan emerges as a pivotal molecule preserving hydration and dynamics. Some …

Factors Associated With Recanalization And Reintervention Following Below Knee Polidocanol Endovenous Microfoam Ablation For Great Saphenous And Small Saphenous Veins, John Fang, Christian Fang, Andy Moyal, Enrico Ascher, Anil Hingorani, Natalie Marks

Rowan-Virtua School of Osteopathic Medicine Departmental Research

BACKGROUND: Polidocanol endovenous microfoam (PEM) has been used to treat lower extremity venous reflux for almost one decade with specific advantages for below knee (BK) truncal veins where thermal ablation poses a risk of injury to adjacent nerves. The current literature of the BK segment often examines short-term outcomes with modest sample sizes. We aim to identify factors associated with recanalization and reintervention in this subset of patients.

METHODS: We performed a retrospective study of a prospectively maintained database of patients from a single institution who underwent 1% PEM ablation for BK great saphenous vein (GSV) and small saphenous vein …

In Silico Modelling And Docking Simulation Of Egfr-Targeted Diphtheria Toxin Chimera With Various Targeting Moieties, Muhammad Afif Naufal Bmed, Benedictus Ansell Susanto Bmed, Talitha Dinda Gunawan Bmed, Azhar Ridha Lukman Bmed, Alifa Rahma Rizqina Bmed, Muhammad Misbahul Fuad Bmed

Indonesian Journal of Medical Chemistry and Bioinformatics

Introduction: Cancer is a major etiology of death worldwide due to high mortality and suboptimal medicine. However, an emerging field, targeted therapy enabled a more selective and effective therapeutic action. This article aims to analyze in-silico the hypothetical targeted therapy agent that is combinations of conjugate consisting of EGFR targeting moieties and diphtheria toxin (DT-390).

Method: Our novel peptide is a conjugate of a novel EGFR targeting peptide and DT-390, forming a chimera. The tertiary structure was predicted using AlphaFold 2.0. The best IDDT scoring and stereochemistry profiles were utilized. The HADDOCK2.4 webserver modelled the docking between our …

Methamphetamine-Induced Dna Double-Stranded Breaks: The Impact Of The Dopamine Transporter And Insights Into The Mechanisms Of Dna Damage In Mouse Neuro 2a Cells, Lizette Couto

Dissertations, Theses, and Capstone Projects

Methamphetamine (METH) abuse remains a global health concern, with emerging evidence highlighting its genotoxic potential. In the central nervous system METH enters dopaminergic cells primarily through the dopamine transporter (DAT), which controls the dynamics of dopamine (DA) neurotransmission by driving the reuptake of extracellular DA into the presynaptic neuronal cell. Additional effects of METH on the storage of DA in synaptic vesicles lead to the dysregulated cytosolic accumulation of DA. Previous studies have shown that after METH disrupts intracellular vesicular stores of DA, the excess DA in the cytosol is rapidly oxidized. This generates an abundance of reactive oxygen species …

Nanodiscs: A Novel Approach To The Study Of The Methionine Abc Transporter System, Michael T. Winslow

Master's Theses

Membrane transporter proteins play the vital role of moving compounds in and out of the cell and are essential for all living organisms. ATP Binding Cassette (ABC) family transporters function both as importers and exporters in prokaryotes. MetNI is an E. coli Type I ABC transporter responsible for the uptake of methionine into the cytosol from the cell periplasmic space through the cell membrane to maintain intracellular methionine pools. ABC transporters, like other membrane proteins, are most often mechanistically and structurally studied in vitro, solubilized by detergents. However, detergent micelles may affect the conformational changes of membrane proteins relative to …

Studying The Stability Of Collagen/Heparin Coatings To Be Used In Cell Therapy Applications, Gavin Mussino

Biological Sciences Undergraduate Honors Theses

This honors thesis aims to investigate the reusability and performance of cell coatings for cell therapy applications. Cell therapy, which involves the use of human cells to repair or replace damaged tissues, holds immense potential for medical advancements. However, ensuring the survival and functionality of transplanted cells remains a significant challenge. We focused on studying the effectiveness of coatings applied to cells for improved cell growth and viability. The research project involved the preparation of the coatings using a layer-by-layer method and the subsequent seeding of cells. The coated cells were then subjected to a series of experiments to assess …

The Developing Effects Of Potassium Ferricyanide On Tetrahymena, Katelyn Coronell

Whittier Scholars Program

Potassium Cyanide is a highly toxic chemical asphyxiant that interferes with the body's ability to use oxygen, typically by directly affecting the body by ingestion, inhalation, skin contact, or eye contact(CDC, 2011). Due to its high toxicity, the main effect that leads to the downfall of the organism begins with the cessation of aerobic metabolism; it does this by cyanide binding to the ferric ions and inhibiting cytochrome oxidase within the mitochondria (Zhang, 2015). There are no physical dangers the substance causes. Although, there are many chemical dangers. If used at temperatures higher than 70℉ The substance may produce toxic …

Second Generation Phenyloxadiazolyl Methyl Sulfones For Thiol-Specific Bioconjugations, Guillaume Dewaele-Le Roi

Dissertations, Theses, and Capstone Projects

The role of antibody-based molecular agents for diagnosis and therapy of cancer has expanded significantly over the past decades. However, most of these constructs are synthesized using traditional bioconjugation methods based on the random ligations between the molecular cargo and lysine residues within the protein. These non-specific approaches can create poorly defined conjugates with suboptimal immunoreactivity and in vivo performance while Site-specific approaches to antibody bioconjugation based on ligations between maleimides and free cysteine residues have long stood as attractive alternatives. Yet the inherent instability of the thiol-maleimide linkage has fueled the search for new, more stable thiol-reactive prosthetic groups. …

Engineered Plga Nanofibers For Drug Delivery, Andrew Mancuso

Dissertations, Theses, and Capstone Projects

Poly-lactic-co-glycolic acid (PLGA) polymers are rapidly gaining momentum as a platform for next-generation drug delivery systems due to their ease and low cost of synthesis, favorable biocompatibility and biodegradability, and lack of toxicity. In particular, the application of drug-loaded PLGA nanofibers directly to a target tissue may represent a promising alternative to traditional routes of drug administration (e.g., oral, injectable) as they offer the potential to greatly improve bioavailability, increase efficacy, and reduce off-target toxicity. Furthermore, the use of such a system may potentially allow for greater flexibility in clinical drug development, by enabling the use of compounds which have …