Department of Physics

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

Matrix rigidity sensing regulates a large variety of cellular processes and has important implications for tissue development and disease. However, how cells probe matrix rigidity, and hence respond to it, remains unclear. Here, we show that rigidity sensing and adaptation emerge naturally from actin cytoskeleton remodelling. Our in vitro experiments and theoretical modelling demonstrate a biphasic rheology of the actin cytoskeleton, which transitions from fluid on soft substrates to solid on stiffer ones. Furthermore, we find that increasing substrate stiffness correlates with the emergence of an orientational order in actin stress fibres, which exhibit an isotropic to nematic transition that we characterize quantitatively in the framework of active matter theory. These findings imply mechanisms mediated by a large-scale reinforcement of actin structures under stress, which could be the mechanical drivers of substrate stiffness-dependent cell shape changes and cell polarity.

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Nature Communications

Adaptive rheology and ordering of cell cytoskeleton govern matrix rigidity sensing

(Graph Presented) The production of large amounts of hydrogen bubbles, typical of electrochemical delamination methods based on the electrolysis of water, results in mechanical damage to graphene during the delamination, transfer, and drying steps. Here a novel 'bubble-free' delamination method is introduced which exploits the electrochemical dissolution of native copper oxide at a potential lower than that required for the formation of hydrogen bubbles, enabling the production of defect-free graphene stack. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA.

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'Bubble-free' electrochemical delamination of CVD graphene films

Increasing evidence has shown that mechanical cues from the environment play an important role in cell biology. Mechanotransduction or the study of how cells can sense these mechanical cues, and respond to them, is an active field of research. However, it is still not clear how cells sense and respond to mechanical cues. Thus, new tools are being rapidly developed to quantitatively study cell mechanobiology. Particularly, force measurement tools such as micropillar substrates have provided new insights into the underlying mechanisms of mechanosensing. In this chapter, we provide detailed protocol for fabrication, characterization, functionalization, and use of the micropillar substrates. © 2015 Elsevier Inc.

Methods in Cell Biology

Micropillar substrates: A tool for studying cell mechanobiology

Magnesium reinforced with 0.7 volume percentage of yttria is considered to be one of the most promising light weight structural nanocomposite materials, whose performance was further enhanced with incorporation of 0.3 volume percentage of nano copper particles. Elongation-to-fracture tensile test revealed that the nano copper particle effectively maintained strengthening effect on magnesium-yttria nanocomposite at up to 100 °C and gradually diminished with further increase in test temperature used in this study. Nano copper particle induced impressive enhancement in magnesium-yttria nanocomposite and led to their potential near net shape fabrication in to intricate shaped objects at a substantially low temperature.

Metals and Materials International

Effect of copper nano particles on high temperature tensile behavior of Mg-Y2O3 nanocomposite

Physical Review E - Statistical, Nonlinear, and Soft Matter Physics

Erratum: Effects of aging in catastrophe on the steady state and dynamics of a microtubule population (Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 91, 052704 (2015))

Several independent observations have suggested that the catastrophe transition in microtubules is not a first-order process, as is usually assumed. Recent in vitro observations by Gardner et al. [M. K. Gardner, Cell 147, 1092 (2011)CELLB50092-867410.1016/j.cell.2011.10.037] showed that microtubule catastrophe takes place via multiple steps and the frequency increases with the age of the filament. Here we investigate, via numerical simulations and mathematical calculations, some of the consequences of the age dependence of catastrophe on the dynamics of microtubules as a function of the aging rate, for two different models of aging: exponential growth, but saturating asymptotically, and purely linear growth. The boundary demarcating the steady-state and non-steady-state regimes in the dynamics is derived analytically in both cases. Numerical simulations, supported by analytical calculations in the linear model, show that aging leads to nonexponential length distributions in steady state. More importantly, oscillations ensue in microtubule length and velocity. The regularity of oscillations, as characterized by the negative dip in the autocorrelation function, is reduced by increasing the frequency of rescue events. Our study shows that the age dependence of catastrophe could function as an intrinsic mechanism to generate oscillatory dynamics in a microtubule population, distinct from hitherto identified ones. © 2015 American Physical Society.

Effects of aging in catastrophe on the steady state and dynamics of a microtubule population

Applied Physics Letters

Electronic transport in graphene-based heterostructures

Force-dependent binding of vinculin to alpha-catenin constitutes the core mechanosensing machinery of cadherin adhesions.

Simultaneous mapping of intra-and extracellular forces at the focal adhesion sites.

Iridates have attracted considerable interest in the last few years due to their potential to host novel electronic and magnetic phases mediated by the combination of strong spin orbit coupling and electronic correlations. Layered honeycomb lattice iridates A_2IrO_3 (A =Na, Li) have been proposed as candidate materials for the realization of the highly frustrated Kitaev interaction as well as correlated topological insulator phases. &nbsp;In this thesis honeycomb iridates and rhodate (Li_2RhO_3) are experimentally investigated. Firstly, synthesis procedure, structural, magnetic, electrical and thermodynamic properties of the very well ordered honeycomb iridates and rhodate are reported including challenges faced due to disorder. Magnetic and electronic structures are also reported which were investigated using different scattering experiments and band structure calculations with the help of different international collaborators. Though both honeycomb iridates were proposed for Kitaev spin liquid state, bulk and microscopic investigation confirmed long range magnetic ordering below 15 K having zigzag and spiral magnetic structure for Na- and Li-system respectively. They also show novel spin-orbit Mott insulting state as proposed for iridates. Experimental investigations of honeycomb iridates raise many questions on the proposed spin Hamiltonians for these systems. &nbsp;To understand magnetic exchange in honeycomb iridates isoelectronic doping at A-site and nonmagnetic dilution at magnetic Ir-site were performed which clearly suggested very different magnetic exchanges in both the systems. Possible spin models for both of these systems are suggested from the comparison of the different proposed models with the experimental evidences. The Honeycomb rhodate Li_2RhO_3 which shows spin glass freezing at low temperature, hints degenerate magnetic ground state and possibility to find a spin liquid state. This thesis is one of the earliest investigations of the proposed Honeycomb lattice spin-orbit materials which can host Kitaev physics.&nbsp;