Speaker Abstracts
Prof. Mahesh S Tirumkudulu
Title: Fluid Mechanics of Thin Liquid Films: From Measuring Viscosity to Detecting Diseases
Abstract: We describe a unique method to measure the viscosity of liquids based on the fluid mechanics of thin films. A drop of sample is spread over a substrate by contacting a blade with the drop and moving the blade across the substrate. The thickness of the film is determined by the capillary number, which measures the competition between the viscous force that smears the liquid over the glass slide and the surface tension that resists the deformation of the interface. We show that the length of the smear for a fixed sample volume is also set by capillary number and can be used as a reliable measure of fluid viscosity. The technique is especially suitable for viscosity measurements of biological fluids where viscosities are low and sample sizes are small. The technique can detect small changes in blood viscosity, enabling it to be used as a non-specific, screening tool for diseases and therapeutic interventions.
We use the aforementioned technique to target Anemia and Sickle-cell disease. Anemia affects nearly a quarter of the world population, mostly concentrated in low-income countries, while sickle-cell (SCD) disease, which is genetically inherited, is widely prevalent in sub-Saharan Africa and central India. Existing screening devices for the diseases are often expensive and limited to single assays, requiring healthcare centers to stock multiple devices for diagnosing different diseases thereby adding costs. The proposed technique enables a rapid, cost-effective screening assay that measures blood viscosity from a single blood drop to aid in the simultaneous screening of anemia and SCD. Viscosity below a threshold due to low hematocrit indicates severe anemia, while a significant viscosity increase due to hardening of red blood cells upon blood deoxygenation signals SCD. The assay exhibits high sensitivity in screening severe anemia and SCD. We anticipate the assay to be useful in screening and monitoring various disease conditions affecting blood viscosity, such as atherosclerosis, hypertension, diabetes, and COVID-19.
References:
1. Mir, M. A., Tirumkudulu, M.S; Soft Matter, 2024, 20, 4358
Prof. Samriddhi Sankar Ray
Title: A high Reynolds number perspective on what makes dense, bacterial suspensions truly turbulent
Abstract: Active turbulence, observed for instance in dense bacterial suspensions, represents a striking example of complex flow in living matter. A long-standing question is whether such intrinsically low-Reynolds-number systems are genuinely turbulent, or instead chaotic flows that merely resemble high-Reynolds-number inertial turbulence. This distinction is subtle but fundamental, as key signatures of classical turbulence — universality, scale invariance, intermittency, and multifractality — are commonly attributed to the largeness of the Reynolds number, seemingly setting turbulence apart from other driven–dissipative systems.
References:
1. Anomalous Diffusion and Levy Walks Distinguish Active Turbulence from Inertial Turbulence, S. Mukherjee, R. K. Singh, M. James and S. S. Ray, Physical Review Letters 127 118001 (2021). [Editors’ Suggestion]
2. Lagrangian Manifestations of Anomalies in Active Turbulence, R. K. Singh, S. Mukherjee and S. S. Ray, Physical Review Fluids 7 033101 (2022).
3. Intermittency, fluctuations and maximal chaos in an emergent universal state of active turbulence, S. Mukherjee, R. K. Singh, M. James and S. S. Ray, Nature Physics 19 891 (2023).
4. The Onset of Intermittency in Active Turbulence, K. V. Kiran, K. Kumar, A. Gupta, R. Pandit and S. S. Ray, Physical Review Letters 134 088302 (2025).
5. Turbulence-Induced Fluctuating Interfaces in Heterogeneously-Active Suspensions, S. Mukherjee, K. Kumar and S. S. Ray, ArXiv:2502.16443
Dr. Shachi Gosavi
Title: A role for the transmembrane domains of class I viral fusion proteins in viral fusion
Abstract: The genomes of enveloped viruses enter the host cell by fusing the viral envelopes (membranes) with host cell membranes. The homotrimeric class I viral fusion proteins (cI-VFPs) enable this fusion. The large ectomembrane domains of cI-VFPs are anchored to the viral envelope through the transmembrane domain (TMD) which is a homotrimer of single-pass transmembrane helices (spTMHs). These ectomembrane domains undergo a large conformational transition which unfurls the fusion peptides which dock the host membrane. A supsequent conformational transition brings together the two membranes and promotes fusion. It has generally been assumed that the cI-VFP spTMHs play a passive anchoring role in the fusion process. We studied the dynamics and self-assembly of the spTMHs of the SARS-CoV-2, cI-VFP, spike, using multiscale MD simulations and found that the spike spTMH is long and has a hydrophobic mismatch with a model POPC membrane. Atomistic simulations show that this mismatch makes the spike spTMH dynamic and it bobs and tilts in the membrane. Coarse-grained trimerization simulations show diverse dimeric and trimeric populations whose structure depends on the conformation of the spTMH protomer. Of these populations, a symmetric spTMH trimer has the symmetry of the prefusion spike protein structure while the asymmetric conformations could promote membrane fusion through the stabilization of a fusion intermediate. Using bioinformatics analyses, we show that similar hydrophobic mismatches exist in other cI-VFP spTMHs and the consequent spTMH dynamics may promote membrane fusion by both enabling the pre-fusion to post-fusion conformational transition as well as by perturbing the membrane. I will then show using coarsegrained structure-based model simulations that TMD dynamics can affect the timing of the ectomembrane domain conformational conversion of the spike and further, show using all-atom simulations that the spTMH of the influenza cI-VFP, hemaglutinnin, behaves similar to that of the spike and perturbs the membrane. *Work done with Dr. Sahil Lall, Dr. Avijeet Kulshrestha, Arkadeep Banerjee, Naren C., Antony John, Prof. M. K. Mathew and Prof. P. Balaram
Prof. Prabal Maiti
Title: Molecular origin of Branch selectivity in Photosystem II
Abstract: Photosynthesis, the fundamental process sustaining life on Earth, depends on the Photosystem II (PSII) reaction center’s ability to initiate the charge transport process. Using multi-scale simulation methodologies, we have investigated this charge transport process with a focus on the dissimilarity between the two branches of the PSII reaction center, D1 and D2. Utilizing Marcus theory, we have calculated the reorganization energies and activation barriers for all the key steps involved in the charge transport process. Our analysis reveals that while both D1 and D2 branches exhibit similarities in the initial stages, the rate-determining step in the D2 branch has a significantly higher activation barrier (0.2 eV) than D1 branch (0.1 eV), suggesting a much less favorable energetic landscape. Further, the calculation of current-voltage (I-V) characteristics confirms the higher resistance in the D2 branch compared to the D1 branch, emphasizing its non-conductive nature.
References:
1. Unveiling the Charge Transport Blockade in the D2 Branch of Photosystem II Reaction Center Aditya Kumar Mandal, Shubham Basera, William A Goddard III and Prabal K Maiti (PNAS 2025)
Dr. K Ramya
Title: Proton Exchange Membrane Fuel Cells (PEMFCs)
Abstract: Proton Exchange Membrane Fuel Cells (PEMFCs) are electrochemical devices that convert hydrogen and oxygen into electricity, water, and heat. Transitioning PEMFC technology from academic research to widespread commercial adoption requires addressing several critical challenges, particularly in large-scale manufacturing. One major challenge in the automation of continuous fabrication of catalyst-coated membranes (CCMs) is the formation of surface defects during the coating process. If these defects remain unidentified during CCM fabrication, they can lead to performance degradation or failure of the PEMFC stack. Therefore, thorough inspection and accurate identification of defects in each cell prior to stack assembly are essential. This work investigates the various types of defects that occur in CCMs, examines their effects on fuel cell performance, and discusses the correlation between specific defect types and performance degradation.
Prof. Naga Phani B Aetukuri
Title: Solid State Batteries: Hope, Hype and Reality
Abstract: In this talk, we will introduce the utility and necessity of solid-state batteries and their relevance for energy transition. Next, we will discuss the broad challenges in enabling solid state batteries. We will then discuss our work on Solid State Li-ion batteries with garnet-based electrolytes. First, we will discuss the broad mechanisms that underpin lithium filamentary growth in solid-state Li-ion batteries followed by some of our early work on refractory metal interlayers. We will then discuss the role of impurities in solid state electrolytes in dictating critical densities for lithium filamentary growth; the impedance modeling approach for accurate determination of impurities and the correlation with critical current densities. Time permitting, we will touch upon expected charge transfer resistances at ‘clean’ solid-solid electrode/electrolyte interfaces and its implication for solid state batteries.
References:
1. Raj, V.; Venturi, V.; Kankanallu, V. R.; Kuiri, B.; Viswanathan, V.; Aetukuri, N. P. B. Nature Materials 2022 21, 1050-1056
Dr. Janhavi Raut
Title: SOAP: A continuing sustainability journey
Abstract: Consumer products of everyday use like soaps, shampoos, toothpastes etc. while indispensable for our health and daily hygiene, also consume a significant amount of material resources mainly owing to the high volumes consumed. These material resources can be oils like Palm used for saponification or petroleum based surfactants, both of which carry significant greenhouse gas (GHG) impact. With the emphasis on sustainability and targets to reduce of GHG emissions, there is a need to critically re-look at the role played by the various ingredients in these products and re-design them for material efficiency while maintaining the consumer functionality. This re-design of products that have undergone little change since they were first industrially produced in the late 1800’s can have massive environmental impacts while potentially providing avenues to create better products with novel benefits. We will use soap bar as an example to illustrate this journey.
Prof. Navneet Kumar Gupta
Title: Carbon Circularity through Biomass Valorization and CO₂ Utilization
Abstract: The transition toward a sustainable carbon economy requires efficient strategies for closing the carbon cycle by valorizing renewable resources and utilizing carbon dioxide as a chemical feedstock. This talk focuses on integrated approaches to carbon circularity through biomass valorization and CO₂ utilization, emphasizing catalytic pathways that enable the production of high-value chemicals and fuels.
Biomass-derived platform molecules are explored as renewable carbon sources for the synthesis of drop-in chemicals, with particular attention to the production of 1,6-hexamethylenediamine and liquid fuels using advanced catalytic systems. Strategies for maximizing carbon efficiency, selectivity, and process intensification in biomass conversion are discussed.
For effective CO₂ utilization, the talk highlights the synthesis of cyclic carbonates using biomass-derived feedstocks, demonstrating how coupling renewable substrates with CO₂ can lead to atom-efficient and industrially relevant products. These approaches highlight the potential of integrated catalytic strategies to transform renewable carbon resources into fuels and chemicals while advancing carbon circularity.
References:
1. Nayak, R.R.; Gupta, N.K., Green Chem. 2025, 27, 8055-8111.
2. Nayak, R.R.; Gupta, N.K., ACS Sustainable Chem. Eng. 2025, 27, 8055-8111.
3. Khairun, H.S.; Parveen, G.; Nayak, R.R.; Chhatria, J.; Kunnikuruvan, S.; Gupta, N.K., ACS Sustainable Chem. Eng. 2025, 27, 8055-8111.
4. Palenicek, P.; Khairun, H.S.; Gupta, N.K. et al. Molecular Catalysis. 2025, 578, 115030.
5. Reif, P.; Gupta, N.K., Rose, M. Green Chem. 2023, 25, 1588-1596.
6. Gupta, N.K.; Palenicek, P.; et al. ACS Sustain. Chem. Eng., 2022, 10, 14560.
Prof. Venugopal Santhanam
Title: Nanostructured Metallic Thin Films for Sensing Applications
Abstract: Metallic nanostructures have been at the forefront of research in nanoscience and technology, due to their unique size-dependent physico-chemical properties. Nanostructured metallic thin films (NMTFs) are emerging as excellent platforms for applications ranging from energy conversion and information storage to environmental sensing and healthcare applications. Both ordered and disordered NMTFs have been fabricated using top-down or bottom-up approaches. Our research group has focused on developing scalable and robust processes for fabricating functional metallic nanostructures. In this talk, I will highlight our process and product development efforts in two areas: (1) ordered and disordered NMTFs for molecular sensing using surface-enhanced Raman spectroscopy (SERS), and (2) the development of flexible tapes for hydrogen leak detection. Finally, I will discuss the prospects for translating these results into practical technologies.