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.

&nbsp;

IIT Palakkad

We report the anisotropic magnetic properties of the ternary compound ErAl2Ge2. Single crystals of this compound were grown by high temperature solution growth technique,using Al:Ge eutectic composition as flux. From the powder x-ray diffraction we confirmed that ErAl2Ge2 crystallizes in the trigonal CaAl2Si2-type crystal structure. The anisotropic magnetic properties of a single crystal were investigated by measuring the magnetic susceptibility, magnetization, heat capacity and electrical resistivity. A bulk antiferromagnetic ordering occurs around 4 K as inferred from the magnetic susceptibility and the heat capacity. The susceptibility is larger along the ab-plane and flattens out below the magnetic transition temperature and the magnetization in the ordered state increases more rapidly along the ab-plane than along the c-axis suggesting that the moments are inclined more towards the ab-plane. The magnetic susceptibility, magnetization and the 4f -derived part of the heat capacity in the paramagnetic regime analysed based on the point charge model of the crystalline electric field (CEF) indicate a relatively low CEF energy level splitting. © 2020 IOP Publishing Ltd.

World University root node

Fulltext

Journal of Physics Condensed Matter

Anisotropic magnetic properties of trigonal ErAl2Ge2 single crystal

We revisit the issue of Lagrangian irreversibility in the context of recent results [H. Xu, Proc. Natl. Acad. Sci. USA 111, 7558 (2014)PNASA60027-842410.1073/pnas.1321682111] on flight-crash events in turbulent flows and show how extreme events in the Eulerian dissipation statistics are related to the statistics of power fluctuations for tracer trajectories. Surprisingly, we find that particle trajectories in intense dissipation zones are dominated by energy gains sharper than energy losses, contrary to flight crashes, through a pressure-gradient driven take-off phenomenon. Our conclusions are rationalized by analyzing data from simulations of three-dimensional intermittent turbulence, as well as from nonintermittent decimated flows. Lagrangian irreversibility is found to persist even in the latter case, wherein fluctuations of the dissipation rate are shown to be relatively mild and to follow probability distribution functions with exponential tails. © 2020 American Physical Society. ©2020 American Physical Society.

Physical Review Fluids

Lagrangian irreversibility and Eulerian dissipation in fully developed turbulence

We explore correlations between dynamics of different microtubules in a bundle, via numerical simulations, using a one-dimensional stochastic model of a microtubule. The guanosine triphosphate (GTP)-bound tubulins undergo diffusion-limited binding to the tip. Random hydrolysis events take place along the microtubule and converts the bound GTP in tubulin to guanosine diphosphate (GDP). The microtubule starts depolymerising when the monomer at the tip becomes GDP-bound; in this case, detachment of GDP-tubulin ensues and continues until either GTP-bound tubulin is exposed or complete depolymerisation is achieved. In the latter case, the microtubule is defined to have undergone a “catastrophe”. Our results show that, in general, the dynamics of growth and catastrophe in different microtubules are coupled to each other; the closer the microtubules are, the stronger the coupling. In particular, all microtubules grow slower, on average, when brought closer together. The reduction in growth velocity also leads to more frequent catastrophes. More dramatically, catastrophe events in the different microtubules forming a bundle are found to be correlated; a catastrophe event in one microtubule is more likely to be followed by a similar event in the same microtubule. This propensity of bunching disappears when the microtubules move farther apart. © 2020, European Biophysical Societies' Association.

European Biophysics Journal

Spatio-temporal correlations between catastrophe events in a microtubule bundle: a computational study

Normal thermal fluctuations of the cell membrane have been studied extensively using high resolution microscopy and focused light, particularly at the peripheral regions of a cell. We use a single probe particle attached non-specifically to the cell-membrane to determine that the power spectral density is proportional to (frequency)-5/3 in the range of 5 Hz to 1 kHz. We also use a new technique to simultaneously ascertain the slope fluctuations of the membrane by relying upon the determination of pitch motion of the birefringent probe particle trapped in linearly polarized optical tweezers. In the process, we also develop the technique to identify pitch rotation to a high resolution using optical tweezers. We find that the power spectrum of slope fluctuations is proportional to (frequency)-1, which we also explain theoretically. We find that we can extract parameters like bending rigidity directly from the coefficient of the power spectrum particularly at high frequencies, instead of being convoluted with other parameters, thereby improving the accuracy of estimation. We anticipate this technique for determination of the pitch angle in spherical particles to high resolution as a starting point for many interesting studies using the optical tweezers. This journal is © The Royal Society of Chemistry.

Soft Matter

Detection of sub-degree angular fluctuations of the local cell membrane slope using optical tweezers

Nanocomposite made of La0.7Sr0.3MnO3 (LSMO) and reduced graphene oxide (rGO) is a promising candidate for non-volatile memory application in oxide electronics. Here, we report bipolar resistive switching (RS) behaviour in (1-x)LSMO.(x)rGO nanocomposite system, for 0.001 ≤x≤ 0.010. The structural characterization revealed the presence of individual constituent phases. The switching behaviour is observed to be very stable over 1000 switching cycles and robust against different voltage sweeping rates with a minimum switching speed of 1.1 μs. An oxygen vacancy induced conduction filament based model is proposed to understand the origin of the switching phenomenon and similar observation is made through high-resolution transmission electron microscopy (HRTEM) measurements. © 2019

Journal of Alloys and Compounds

Structural and resistive switching behaviour in lanthanum strontium manganite - Reduced graphene oxide nanocomposite system

Introduction: Rifabutin (RFB) is a lipophilic, semi-synthetic antibiotic given for the treatment of atypical mycobacterial infections along with drug susceptible tuberculosis infections. The major challenges in its usage include low oral bioavailability (similar to 20\%) mainly due to its low solubility and extensive first pass metabolism. Aim: The present study aims to explore the pharmacokinetics, biodistribution and toxicity of nanocarrier of RFB. Materials and Methods: An experimental animal study was carried out in Institute for Industrial Research and Toxicology, Ghaziabad, Uttar Pradesh, India. RFB nanocarriers were formulated by using solvent diffusion evaporation method with minor modifications and characterised for its physicochemical properties by using various techniques like Field Emission Scanning Electron Microscopy (FESEM), Dynamic Light Scattering (DLS) method, High-Performance Liquid Chromatography (HPLC), X-ray Diffractometry (XRD), in-vitro release study etc. Further nanocarriers were also studied for in-vivo analysis using pharmacokinetics, biodistribution and toxicity studies. GraphPad Prism Software (Version 5.02) was used for the statistical analysis. Results: Nanocarriers of RFB were developed and evaluated for its safety and efficacy. The results of evaluation of nanocarrier for physical and chemical attributes revealed that its particle size obtained was 305-325 nm with low Poly Dispersity Index (PDI) of 0.26-0.36 and the high drug encapsulation efficiency (62.45-70.15\%). The nanocarrier formulation showed a sustained release pattern in Simulated Intestinal Fluid (SIF) upto 48 hours and in Physiological Buffer System (PBS) upto 7 days. The invivo study showed that the nano-lipoidal drug has significant higher Tmax and Cmax plasma value with higher t(1/2)(h) values in comparison to plain drug, Moreover, the slow elimination rate (Kel) resulted in significant (p<0.001) prolonged half-life (t(1/2)), which was many fold higher than the plain drug. No significant change was observed in haematological and liver enzyme profile of rats in plain drug and drug with nano-lipoidal carrier. Nanocarriers showed that there was an increase cell survival rate in MTT assay as compared to normal drug. Conclusion: By using nanotechnology based formulations, dose and dosing frequency of drug administration can be reduced. Thus, RFB drug can be administered in more efficacious manner reducing its toxic side effects, which ultimately improves patient compliance.

JOURNAL OF CLINICAL AND DIAGNOSTIC RESEARCH

Pharmacokinetics, Biodistribution and Toxicity Studies for Nanocarrier of Antitubercular Agent-Rifabutin

In three-dimensional computer simulations of model non-Brownian jammed suspensions, we compute the time required to reach homogeneous flow upon yielding, by analyzing stresses and particle packing at different shear rates, with and without confinement. We show that the stress overshoot and persistent shear banding preceding the complete fluidization are controlled by the presence of overconstrained microscopic domains in the initial solids. Such domains, identifiable with icosahedrally packed regions in the model used, allow for stress accumulation during the shear startup. Their structural reorganization under deformation controls the emergence and the persistence of the shear banding. © 2020 American Physical Society.

Physical Review E

Emergence and persistence of flow inhomogeneities in the yielding and fluidization of dense soft solids

We study the non-equilibrium dynamics caused by slowly taking a quasiperiodic Hamiltonian across its quantum critical point. The special quasiperiodic Hamiltonian that we study here has two different types of critical lines belonging to two different universality classes, one of them being the well known quantum Ising universality class. In this paper, we verify the Kibble Zurek scaling which predicts a power law scaling of the density of defects generated as a function of the rate of variation of the Hamiltonian. The exponent of this power law is related to the equilibrium critical exponents associated with the critical point crossed. We show that the power-law behavior is indeed obeyed when the two types of critical lines are crossed, with the exponents that are correctly predicted by Kibble Zurek scaling. © 2020 IOP Publishing Ltd and SISSA Medialab srl.

Journal of Statistical Mechanics: Theory and Experiment

Adiabatic dynamics of quasiperiodic transverse Ising model

Malaria is a parasitic disease which takes approximately half a million lives every year. The unicellular parasites are transmitted by mosquitoes and mainly affect vascular blood flow by invading red blood cells (RBCs). The pathogenicity of malaria primarily results from substantial changes in the stiffness of infected RBCs and their ability to adhere to endothelial cells and other circulating blood cells, leading to a substantial disruption of normal blood circulation and inflammation of the vascular endothelium. Multiscale modeling of malaria has proved to contribute significantly to the understanding of this devastating disease. In particular, modeling on the level of single infected RBCs allows quantification of their mechanics, cytoadherence, and individual as well as collective behavior in blood flow. Recent modeling advances in this direction are discussed.We show how computational models inmalaria are validated and used for the interpretation of experimental observations or the establishment of new physical hypotheses. Such computational models have a strong potential to elucidate a number of physical mechanisms relevant for malaria and to aid in the development of novel diagnostic tools and treatment strategies. © Springer Nature Switzerland AG 2020.

Handbook of Materials Modeling: Applications: Current and Emerging Materials, Second Edition

Multiscale Modeling of Malaria-Infected Red Blood Cells

Quantum error correction procedures have the potential to enable faithful operation of large-scale quantum computers. They protect information from environmental decoherence by storing it in logical qubits, built from ensembles of entangled physical qubits according to suitably tailored quantum error correcting encodings. To date, no generally accepted framework to characterise the behaviour of logical qubits as quantum memories has been developed. In this work, we show that generalisations of well-established figures of merit of physical qubits, such as relaxation times, to logical qubits fail and do not capture dynamics of logical qubits. We experimentally illustrate that, in particular, spatial noise correlations can give rise to rich and counter-intuitive dynamical behavior of logical qubits. We show that a suitable set of observables, formed by code space population and logical operators within the code space, allows one to track and characterize the dynamical behaviour of logical qubits. Awareness of these effects and the efficient characterisation tools used in this work will help to guide and benchmark experimental implementations of logical qubits.