arXiv subjects

Mamta Yadav

Publications and source records attributed to Mamta Yadav.

11 recordsLinked to original sources

arXiv2026

A mechanistic modeling framework to interpret ACTH stimulation tests across HPA axis adaptation states and glucocorticoid feedback dynamics

The hypothalamic pituitary adrenal (HPA) axis is a key regulatory system coordinating endocrine responses to physiological and psychological stress. While the ACTH stimulation test remains a cornerstone of adrenal function assessment, its interpretation is complicated by the dynamic and adaptive nature of the HPA axis under chronic stress exposure. In particular, prolonged stress induces glandular remodeling, glucocorticoid receptor (GR) resistance and delayed feedback recovery, all of which may alter test outcomes without indicating primary adrenal failure. In this study, we present a mechanistic modeling framework that integrates hormonal kinetics, feedback inhibition and functional mass adaptation of the corticotroph and adrenal compartments. We simulate the HPA axis over $180$ days encompassing three phases - baseline, chronic stress and recovery, while introducing a time varying GR resistance function to mimic feedback desensitization and its resolution. Using this framework, we evaluate both low dose ($1 \mu g)$ and high dose ($250 \mu g)$ ACTH stimulation tests across physiological phases. Our simulations show that cortisol responses are highly sensitive to both the magnitude and timing of stress exposure and that ACTH responsiveness is phase dependent and often blunted during recovery due to persistent feedback resistance. Low dose ACTH testing more reliably reflects partial adrenal adaptation, while high dose tests risks masking dysfunction due to supraphysiological drive. These results highlight the limitations of static testing paradigms and suggest that accounting for glandular plasticity and GR feedback dynamics is essential for effective endocrine diagnosis particularly in stress related or treatment induced adrenal disorders.

q-bio.QM↗

arXiv2026

Exploring Self-Organization of Charged Dust Dimers in Plasma

We investigate the self-organization of charged dust dimers in plasma using Molecular Dynamics (MD) simulations, with emphasis on both positional and orientational ordering. For a finite number of dimers confined by a radial electric field, the system evolves from simple arrangements to ring-like structures as the particle number increases. These rings exhibit diverse orientational states, including radial, transverse, and mixed alignments of the dimer axis, reflecting a strong coupling between spatial confinement and orientational degrees of freedom. For larger systems studied under periodic boundary conditions, bulk-like behavior emerges with coupled positional and orientational correlations. The results highlight the significance of anisotropy in determining equilibrium structures and demonstrate that orientational order plays a crucial role alongside positional ordering in complex plasmas with shaped particles. This work provides motivation for experimental studies involving shaped dust particles to explore orientational ordering phenomena beyond conventional spherical dust particle systems.

physics.plasm-ph↗

arXiv2026

A Boosted Energy Extraction from the CapMix Process by Grafting with Titratable Polymers

Salinity gradient energy offers a sustainable route to convert ionic chemical potential differences into usable power. Capacitive mixing enables this conversion without membranes, but suffers from limited ion regulation at electrode interfaces. Here we show that by grafting electrode surfaces with titrating polymers, the performance can be substantially improved. Using Grand Canonical Monte Carlo simulations with exact image-charge Ewald summations, we demonstrate how the coupled effects of ion adsorption and charge regulation in response to an external potential can be harnessed. Grafted electrodes are shown to deliver substantially more energy relative to bare surfaces, driven by charge regulation effects that exploit the pH difference that typically exists between rivers and the ocean. While the effect is in principle maximized at high grafting densities and moderate chain lengths, the performance is fairly robust to variations of these parameters, within reasonable bounds. Complementary classical polymer Density Functional Theory calculations confirm these trends, validating the mechanistic framework. This work also establishes a practical approach to harvest electrical energy during wastewater neutralization, where acidic (or alkaline) effluents serve as complementary reservoirs, and offers a promising strategy to couple environmental remediation with renewable energy recovery.

cond-mat.soft↗

arXiv2026

Improved Desalination by Polymer Grafting

Freshwater scarcity demands desalination technologies that are efficient, scalable, and sustainable. Capacitive deionisation (CDI) is promising but remains limited by inefficient ion adsorption and poor charge utilisation. Here, we show that suitably chosen polyampholytic block copolymer grafting can substantially enhance CDI performance, via a combination of dipolar response and steric effects. Using mean-field classical density functional theory and grand-canonical Monte Carlo simulations, we demonstrate that such polymer grafted electrodes enable strongly improved desalination performance, without altering the pore architecture. Even an electrode grafting by simple neutral polymers can generate an improvement, although a suitably designed block polymer architecture offers an additional performance gain. These results establish interfacial block copolymer grafting as a powerful route toward high-performance, membrane-free desalination.

cond-mat.soft↗

arXiv2024

Bulk and surface dominated phenomena and the formation of pentagonal structures in 2-D strongly coupled finite dust clusters

This paper explores the prevalence of size-dependent aspects in the context of dust clusters with the help of Molecular Dynamics (MD) simulations in two dimensions. The transition from macroscale (identified by the dominance of the number of dust particles in bulk) to microscale (where the number of particles on the surface dominates) is explored systematically. The dust particles organize in a multi-ringed structure under transverse confinement. The ring size and the number of rings increase with increasing number of dust particles. Interestingly, the formation of an additional ring is always preceded by structures with a pentagonal symmetry in the core. A detailed study of this formation has been investigated under various symmetries of the boundary condition and different values of the shielding potential.

physics.plasm-ph↗

arXiv2024

Game-Based Discovery: Harnessing Mini-Games within Primary Games for Scientific Data Collection and Problem Solving

In the popular video game Batman: Arkham Knight, produced by Rocksteady Studios and released in 2015, the primary protagonist of the game is Batman, a vigilante dressed as a bat, fighting crime from the shadows in the fictitious city of Gotham. The game involves a real-world player who takes up the role of Batman to solve a peculiar side mission wherein they have to reconstruct the clean DNA sequence of a human and separate it from mutant DNA to manufacture an antidote to cure the villain. Although this is undoubtedly a fascinating part of the game, one that was absent in previous Batman games, it showcases an interesting notion of using mini-games embedded within primary games to achieve a particular real-world research objective. Although the DNA data used in this case was not real, there are multiple such instances in video games where mini-games have been used for an underlying motive besides entertainment. Based on popular case studies incorporating a similar method, this study characterizes the methodology of designing mini-games within primary games for research purposes into a descriptive framework, highlighting the process's advantages and limitations. It is concluded that these mini-games not only facilitate a deeper understanding of complex scientific concepts but also accelerate data processing and analysis by leveraging crowd-sourced human intuition and pattern recognition capabilities. This paper argues for strategically incorporating miniaturized, gamified elements into established video games that are mainly intended for recreational purposes.

cs.HC↗

arXiv2024

Evolution of Shielding Cloud Under Oscillatory External Forcing in Strongly Coupled Ultracold Neutral Plasma

This paper investigates the dynamics of crystalline clusters observed in Molecular Dynamics (MD) studies conducted earlier [Yadav, M., et al. Physical Review E, 107(5), 055214(2023)] for ultra-cold neutral plasmas. An external oscillatory forcing is applied for this purpose and the evolution is tracked with the help of MD simulations using the open source LAMMPS software. Interesting observations relating to cluster dynamics are presented. The formation of a pentagonal arrangement of particles is also reported.

physics.plasm-ph↗

arXiv2022

Structure formation by electrostatic interactions in strongly coupled medium

The formation of correlated structures is of importance in many diverse contexts such as strongly coupled plasmas, soft matter, and even biological mediums. In all these contexts the dynamics are mainly governed by electrostatic interactions and result in the formation of a variety of structures. In this study, the process of formation of structures is investigated with the help of Molecular (MD) simulations in 2 and 3 dimensions. The overall medium has been modelled with an equal number of positive and negatively charged particles interacting via long-range pair Coulomb potential. A repulsive short-range Lennard-Jones (LJ) potential is added to take care of the blowing up of attractive Coulomb interaction between unlike charges. In the strongly coupled regime, a variety of classical bound states form. However, complete crystallization of the system, as typically observed in the context of one component strongly coupled plasmas, does not occur. The influence of localized perturbation in the system has also been studied. The formation of a crystalline pattern of shielding clouds around this disturbance is observed. The spatial properties of the shielding structure have been analyzed using the radial distribution function and Voronoi diagram. The process of accumulation of oppositely charged particles around the disturbance triggers a lot of dynamical activity in the bulk of the medium, wherein close encounters between widely separated particles occur. This leads to the formation of a larger number of bigger clusters. There are, however, also instances when bound pairs break up to provide the appropriate signed charge to the shielding cloud. A detailed discussion of these features has been provided in the manuscript.

physics.plasm-ph↗

arXiv2021

Chaotic dynamics of small sized charged Yukawa Dust Clusters

In a recent work, [1] the equilibrium of a cluster of charged dust particles mutually interacting with screened Coulomb force and radially confined by an externally applied electric field in a 2-D configuration was studied. It was shown that the particles arranged themselves on discrete radial rings forming a lattice structure. In some cases with the specific number of particles, no static equilibrium was observed; instead, angular rotation of particles positioned at various rings was observed. In a two-ringed structure, it was shown that the direction of rotation was opposite. The direction of rotation was also observed to change apparently at random time intervals. A detailed characterization of the dynamics of small-sized Yukawa clusters has been carried out in the present work. In particular, it has been shown that the dynamical time reversal of angular rotation exhibits chaotic behavior.

physics.plasm-ph↗

arXiv2020

The solvent mediated interaction potential between solute particles: Theory and applications

In this paper we develop a theory to calculate the solvent mediated interaction potential between solute particles dispersed in a solvent. The potential is a functional of the instantaneous distribution of solute particles and is expressed in terms of the solute-solvent direct pair correlation function and the density-density correlation function of the bulk solvent. The dependence of the direct pair correlation function on multi-point correlations of the solute distribution is simplified with a mean field approximation. A self consistent approach is developed to calculate the effective potential between solute particles, the solute-solvent and the solute-solute correlation functions. The significance of the solvent fluctuations on the range of the effective potential is elucidated. The theory is applied to calculate equilibrium properties of the Asakura-Oosawa (AO) model for several values of solute and solvent densities and for several values of the particles size ratio. The results give a quantitative description of many-body effect on the effective potential and on the pair correlation functions.

cond-mat.soft↗

arXiv2020

Dynamical states in two-dimensional charged dust particle clusters in plasma medium

The formation of novel dynamical states for a collection of dust particles in two dimensions has been shown with the help of Molecular Dynamics (MD) simulation. The charged dust particles interact with each other with Yukawa pair potential mimicking the screening due to plasma. Additionally, an external radial confining force has also been applied to the dust particles to keep them radially confined. When the particle number is low ( say a few), they get arranged on the radial location corresponding to multiple rings/shells. For specific numbers, such an arrangement of particles is stationary. However, for several cases, the cluster of dust particles relaxes to a state for which the dust particles on rings display inter-shell rotation. For a larger number of dust particles ( a few hundred for instance ) a novel equilibrium state with coherent rigid body displaying angular oscillation of the entire cluster is observed. A detailed characterization of the formation of these states in terms of particle number, coupling parameter, etc., has been provided.

physics.plasm-ph↗