Research Cafe: Parameshwaran Pasupathy, Rebecca Risman & Haydee Pacheco
Research Cafe: January 24, 2024
3:00 - 4:00pm
The Hatchery Innovation Studio, Alexander Library
169 College Ave., New Brunswick
Zoom option available.
~Snacks & coffee provided!~
1.) "On The Micromechanics of Onset and Evolution of Damage in Brain White Matter: A Computational Primer" by Parameshwaran Pasupathy
Abstract: Axonal nerve damage in the central nervous system (CNS) white matter is among the factors responsible for the deterioration in brain tissue's mechanical and functional performance during trauma-like events. The onset and evolution of mechanical, and consequently functional, axonal damage are attributed to the magnitude, frequency, and repetitiveness of large loads, deformations, or a combination of the above factors. In this study, we develop a microstructural model of CNS brain white matter (BWM) that characterizes the onset and evolution of damage in axons surrounding the ECM. Representative elemental volumes (REV) of axons of varying diameters and tortuosity are embedded in ECM. A hyperelastic strain energy density function describes the material behavior of the axons and ECM. Damage is described as a progressive softening of the material model due to repeated displacement loading boundary conditions. The softening of the material is characterized by introducing a damage criterion within the strain energy density function. The effects of axon tortuosity, volume fraction, and number of loading cycles are analyzed in a parametric study. The model seeks to discern the micromechanics of cumulative axonal damage in mTBI due to repeated head impacts, as seen in contact sports, domestic abuse, and military training and service scenarios.
Speaker Bio: Parameshwaran Pasupathy is a 4th year PhD student at the Department of Mechanical and Aerospace Engineering. His dissertation is on the multi-scale modeling of brain tissue, which is at the intersection of mechanobiology, computational solid mechanics, and interfacial mechanics. His interdisciplinary research on micro-scale modeling of white matter seeks to develop a fundamental understanding of brain injury and its relevance in detecting mTBI (mild-Traumatic Brain Injury), which is currently undetectable by standard diagnostic tools (such as MRI and DTI.). Paramesh has a Masters degree in Aerospace Engineering from the University of Michigan. Prior to beginning his PhD at Rutgers, Paramesh worked as an Senior Technical Engineer for Siemens PLM as a part of their HEEDS multi-disciplinary design optimization team.
2.) "Internal fibrinolysis of fibrin clots is driven by pore expansion" by Rebecca Risman
Abstract: Blood clots are critical in cessation of bleeding following injury. However, their action is transient and after performing their physiological function they must be resolved through a process known as fibrinolysis. Fibrin-bound tissue plasminogen activator (tPA) converts nearby plasminogen into active plasmin, which is bound to the fibrin network, breaking it down into fibrin degradation products and releasing the entrapped blood cells. It is poorly understood how changes in the fibrin structure and molecular interactions influence the biochemical regulation and behavior of internal fibrinolysis. We used a combination of experiments and mathematical modeling to study fibrin structure and molecular interactions that restrict internal fibrinolysis. Analysis of simulations and experiments indicate that fibrinolysis is driven by pore expansion of the fibrin network. We show that this effect is strongly influenced by the ratio of fibrin:lytic enzyme when compared to absolute enzyme concentration. It is essential to consider the molecular interactions when studying internal fibrinolysis both experimentally and in the clinic. An improved understanding of effective internal lysis can aid in development of better monitoring techniques to avoid thrombotic or bleeding risk, as well as in the design of novel enzymatic treatments to overcome the innate challenges with internal lysis.
Speaker Bio: Rebecca Risman is a 4th year PhD student in the Biomechanics of Blood Lab working under the guidance of Dr. Valerie Tutwiler. She graduated from Rutgers in 2019 with a bachelor’s in biomedical engineering. Her current research focuses on the mechanisms of blood clot resistance to break down (fibrinolytic resistance) due to diseased conditions. Rebecca was awarded a two-year pre-doctoral fellowship from the New Jersey Commission for Cancer Research to probe the mechanisms of cancer-associated thrombosis. She is a trainee in the Rutgers NIH Biotechnology Training Program and a fellow in the PreDoctoral Leadership Develop Academy. Rebecca enjoys scientific communication to general and niche communities and thanks the School of Graduate Studies for providing the Research Café for this platform.
3.) "Intermittent luminescence of silver nanoparticles" by Haydee Pacheco
Abstract: We investigate the intrinsic luminescence blinking behavior of AgNPs using single-particle spectroscopy. We specifically investigate the blinking behavior of AgNPs at green and red wavelengths. In addition, we investigate the shifts in crystal structure, binding energy of silver and fermi level of AgNPs to understand how various shapes, sizes and compositions affect the electronic structure of AgNPs. Our results indicate that crystallization-induced changes in interparticle distance, surface composition, electronic structure, and crystal structure are associated with alterations in blinking characteristics at red and green wavelengths. Our work highlights the wavelength-dependent nature of AgNP blinking and the complexity of the underlying mechanisms. These findings also provide new insights into the underlying mechanisms of blinking behavior in plasmonic nanostructures and have implications for the design of plasmonic devices for sensing, imaging, and other applications.
Speaker Bio: Materials science graduate student working in plasmonics, expertise in nanofabrication techniques and optoelectronic devices
About Research Cafe
Research Café brings together the entire graduate student community of Rutgers University-New Brunswick/Piscataway campus to strengthen scholarly literacy and interdisciplinary research communication by providing a platform for budding researchers to connect, share their in-progress research or scholarship, and benefit from peer feedback in a friendly and low-stakes setting.
Research Café is a monthly, one-hour event to occur at rotating locations across the Rutgers New Brunswick/Piscataway campus (a Zoom option will be available, too). Each event will feature:
- Presentations (10-12 min. each) from two graduate students from across disciplinary areas ranging from engineering and biology to history and anthropology.
- A Q&A dialogue with peers and attendees.
- Conversational time over refreshments and snacks.
Sign up to attend in person or on Zoom at https://grad.rutgers.edu/research-cafe.
Questions? Contact the program coordinators: