Surajit Sengupta

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Chromosomes within eukaryotic cell nuclei at interphase are not positioned at random, since gene-rich chromosomes are predominantly found towards the interior of the cell nucleus across a number of cell types. The physical mechanisms that could drive and maintain the spatial segregation of chromosomes based on gene density are unknown. Here, we identify a(More)
A crystalline solid exhibits thermally induced localised non-affine droplets in the absence of external stress. Here we show that upon an imposed shear, the size of these droplets grow until they percolate at a critical strain, well below the value at which the solid begins to yield. This critical point does not manifest in most thermodynamic or mechanical(More)
A systematic coarse graining of microscopic atomic displacements generates a local elastic deformation tensor D as well as a positive definite scalar χ measuring nonaffinity, i.e., the extent to which the displacements are not representable as affine deformations of a reference crystal. We perform an exact calculation of the statistics of χ and D and their(More)
We show, using molecular-dynamics simulations, that a two-dimensional Lennard-Jones solid exhibits droplet fluctuations characterized by nonaffine deviations from local crystallinity. The fraction of particles in these droplets increases as the mean density of the solid decreases and approaches ≈20% of the total number in the vicinity of the fluid-solid(More)
We study the phenomenon of evaporation-driven self-assembly of a colloid suspension of silica microspheres in the interior region and away from the rim of the droplet on a glass plate. In view of the importance of achieving a large-area, monolayer assembly, we first realize a suitable choice of experimental conditions, minimizing the influence of many other(More)
We report computer simulation studies of the kinetics of ordering of a two-dimensional system of particles on a template with a one-dimensional periodic pattern. In equilibrium, one obtains a reentrant liquid-solid-liquid phase transition as the strength of the substrate potential is varied. We show that domains of crystalline order grow as ~t(1/z), with(More)
Elastic moduli and dislocation core energy of the triangular solid of hard disks of diameter σ are obtained in the limit of vanishing dislocation-an-tidislocation pair density, from Monte Carlo simulations which incorporates a constraint, namely that all moves altering the local connectivity away from that of the ideal triangular lattice are rejected. In(More)
We show that a small crystal trapped within a potential well and in contact with its own fluid responds to large compressive stresses by a novel mechanism--the transfer of complete lattice layers across the solid-fluid interface. Further, when the solid is impacted by a momentum impulse set up in the fluid, a coherently ejected lattice layer carries away a(More)
We describe a phase transition that gives rise to structurally non-trivial states in a two-dimensional ordered network of particles connected by harmonic bonds. Monte Carlo simulations reveal that the network supports, apart from the homogeneous phase, a number of heterogeneous "pleated" phases, which can be stabilised by an external field. This field is(More)