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

Mammalian SIRT7 is a member of the sirtuin family that regulates multiple biological processes including genome stability, metabolic pathways, stress responses, and tumorigenesis. SIRT7 has been shown to be important for ribosome biogenesis and transcriptional regulation. SIRT7 knockout mice exhibit complications associated with fatty liver and increased aging in hematopoietic stem cells. However, the molecular basis for its biological function remains unclear, in part due to the lack of efficient enzymatic activity in vitro. Previously, we have demonstrated that double-stranded DNA could activate SIRT7's deacetylase activity in vitro, allowing it to deacetylate H3K18 in the context of chromatin. Here, we show that RNA can increase the catalytic efficiency of SIRT7 even better and that SIRT7 can remove long chain fatty acyl groups more efficiently than removing acetyl groups. Truncation and mutagenesis studies revealed residues at both the amino and carboxyl termini of SIRT7 that are involved in RNA-binding and important for activity. RNA immunoprecipitation-sequencing (RIP-seq) identified ribosomal RNA (rRNA) as the predominant RNA binding partner of SIRT7. The associated RNA was able to effectively activate the deacetylase and defatty-acylase activities of SIRT7. Knockdown of SIRT7 increased the lysine fatty acylation of several nuclear proteins based on metabolic labeling with an alkyne-tagged fatty acid analog, supporting that the defatty-acylase activity of SIRT7 is physiologically relevant. These findings provide important insights into the biological functions of SIRT7, as well as an improved platform to develop SIRT7 modulators. © 2016 American Chemical Society.

World University root node

Department of Chemistry

ACS Chemical Biology

SIRT7 is an RNA-activated protein lysine deacylase

Prion-like misfolding of superoxide dismutase 1 (SOD1) is associated with the disease ALS, but the mechanism of misfolding remains unclear, partly because misfolding is difficult to observe directly. Here we study the most misfolding-prone form of SOD1, reduced un-metallated monomers, using optical tweezers to measure unfolding and refolding of single molecules. We find that the folding is more complex than suspected, resolving numerous previously undetected intermediate states consistent with the formation of individual β-strands in the native structure. We identify a stable core of the protein that unfolds last and refolds first, and directly observe several distinct misfolded states that branch off from the native folding pathways at specific points after the formation of the stable core. Partially folded intermediates thus play a crucial role mediating between native and non-native folding. These results suggest an explanation for SOD1's propensity for prion-like misfolding and point to possible targets for therapeutic intervention. © 2017 The Author(s).

Fulltext

Nature Communications

Partially native intermediates mediate misfolding of SOD1 in single-molecule folding trajectories

The reduction of disulfides has a broad importance in chemistry, biochemistry and materials science, particularly those methods that use mechanochemical activation. Here we show, using isotensional simulations, that strikingly different mechanisms govern disulfide cleavage depending on the external force. Desolvation and resolvation processes are found to be crucial, as they have a direct impact on activation free energies. The preferred pathway at moderate forces, a bimolecular SN2 attack of OH- at sulfur, competes with unimolecular C-S bond rupture at about 2 nN, and the latter even becomes barrierless at greater applied forces. Moreover, our study unveils a surprisingly rich reactivity scenario that also includes the transformation of concerted SN2 reactions into pure bond-breaking processes at specific forces. Given that these forces are easily reached in experiments, these insights will fundamentally change our understanding of mechanochemical activation in general, which is now expected to be considerably more intricate than previously thought. © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.

Nature Chemistry

Unexpected mechanochemical complexity in the mechanistic scenarios of disulfide bond reduction in alkaline solution

In orthogonal frequency division multiplexing systems, reduced feedback schemes provide essential channel state information from the users to the base station (BS) without overwhelming the uplink. For the practically important best-M scheme, in which each user feeds back only its M strongest subchannels and their indices to the BS, we derive a novel, throughput-optimal scheduling and rate adaptation policy that enables the BS to schedule the best user and its data rate for all the subchannels. The policy exploits the structure of the information fed back by the best-M scheme and the correlation among subchannel gains. We present it in closed-form for the widely studied exponential correlation model. Using insights gleaned from the optimal policy, we propose a novel, low-complexity two subchannel reduction approach, which is seen empirically to be near-optimal and easily handles practically important general channel correlation models, quantized feedback, and co-channel interference in multi-cell scenarios. Compared with several ad hoc approaches, the proposed approaches improve the cell throughput without any additional feedback. A modified gradient-based opportunistic scheduler is also proposed to ensure user fairness. © 2017 IEEE.

Department of Electrical Engineering

IEEE Transactions on Communications

Throughput-Optimal Scheduling and Rate Adaptation for Reduced Feedback Best-$M$ Scheme in OFDM Systems

Visualization of work surface topography through simulations is very challenging task in grinding process due to the complexity of wheel-work interactions with a very high number of cutting points (grits). Kinematic mapping of abrasive grits on a three-dimensional wheel topography enables the evaluation of ground surface topography through simulations. In this paper, a method for generating the ground surface topography based on wheel specifications is presented. Abrasive grits size, abrasives volume percentage and their nature of distribution on the wheel surface are considered in the modeling and visualization of wheel topography. The simulation results of ground surface topographies prove the feasibility of the developed method.

Department of Mechanical Engineering

Applied Mechanics and Materials

A Method to Predict and Visualize the Wheel and Work Surface Topography in Surface Grinding

Low frequency switching of voltage source inverters generates low order harmonic voltages in the output causing torque and speed ripple. In this paper, a multilevel space vector diagram formed by nine-concentric octadecagons (polygons with 18 sides) using a single DC source is presented which eliminates lower order harmonics till seventeenth order from the phase voltage output over the entire modulation range including overmodulation. The topology consists of a flying capacitor (FC) inverter followed by a capacitor fed cascaded H-bridge (CHB) inverter. Single DC source permits easy four quadrant operation. The PWM scheme implemented results in quasi-square waveform operation of the FC inverter resulting in low switching losses. The CHB inverter switching removes the harmonics generated by FC inverter, but operates at a lower voltage. Hence the switching loss is low in the CHB inverter also. The power circuit topology, the formation of the space vector structure and the steady state and transient simulation results are presented in this paper. © 2016 IEEE.

IEEE International Conference on Power Electronics, Drives and Energy Systems, PEDES 2016

A multilevel nine-concentric octadecagonal space vector structure for induction motor drives using a single DC source

This paper proposes a novel six-phase stacked multilevel inverter drive with only one dc source for a six-phase IM with symmetrically placed windings (60° apart). Using one dc source allows direct ac-ac conversion and the inverter can feed the power back to the grid at any power factor. This paper presents a systematic approach to use one dc source for the six-phase stacked multilevel inverter fed symmetric IM drive. Here the individual dc supply is realized by series connected (split) capacitors with inherent balancing of the neutral point (dc link capacitor mid point) current within a switching cycle. This also helps in reducing the dc-link capacitor size. To verify the concept experimentally, a six-phase stacked nine-level inverter is developed in the laboratory for a symmetric six-phase IM and it is run with V/f control. Detailed experimental results are presented to validate the concept. © 2016 IEEE.

IEEE Transactions on Industrial Electronics

Novel Symmetric Six-Phase Induction Motor Drive Using Stacked Multilevel Inverters With a Single DC Link and Neutral Point Voltage Balancing

This paper presents a new wide-area backup protection scheme based on the phase angle of positive-sequence integrated impedance (PAPSII). The proposed scheme uses phasor measurement units (PMUs) that comply with standard C37.118.1-2011 for retrieving the phasor information. The PMUs provide the positive-sequence phasor information of the voltage and current signals at each and every bus of a system to a phasor data concentrator (PDC). The positive-sequence integrated impedance of each line of the system is extracted, and the PAPSII of each line is continuously monitored at the PDC. The values of the PAPSII help in identifying the faulted line of the power transmission system. The proposed scheme is extensively tested for different types of fault scenarios on a three-machine nine-bus power transmission network on a real-time digital simulator platform. Critical issues such as voltage inversion, current inversion, load encroachment, and the power swing are addressed in the proposed scheme. The test results indicate that the proposed scheme can overcome the limitations of existing backup protection schemes and can provide a reliable protection measure. © 2007-2012 IEEE.

IEEE Systems Journal

A new wide-area backup protection scheme for series-compensated transmission system

This paper considers a stochastic model predictive control of linear parameter-varying (LPV) systems described by affine parameter dependent state-space representations with additive stochastic uncertainties and probabilistic state constraints. In computing the prediction dynamics for LPV systems, the scheduling signal is given a stochastic description during the prediction horizon, which aims to overcome the shortcomings of the existing approaches where the scheduling signal is assumed to be constant or allowed to vary in a convex set. The above representation leads to LPV system dynamics consisting of additive and multiplicative uncertain stochastic terms up to second order. The prediction dynamics are reposed in an augmented form, which facilitates the feasibility of probabilistic constraints and closed-loop stability in the presence of stochastic uncertainties. © 2017 American Automatic Control Council (AACC).

Proceedings of the American Control Conference

Stochastic model predictive control for LPV systems

This work reports the photocatalytic activity of undoped tin oxide (TO) and F doped tin oxide (FTO) thin films for MB dye degradation under visible light irradiation. A facile homemade jet nebulizer spray pyrolysis technique was employed to prepare these samples. The results indicate that FTO film exhibits superior photocatalytic activity compared to TO film. Dye degradation of nearly 95\% is achieved using FTO film at 90 min whereas TO film degrades only 78\% of dye molecules in the same time interval. This enhancement for FTO films might be due to the generation of large number of free electrons caused by the fluorine incorporation. The mechanism behind the enhancement of photocatalytic activity of FTO films is discussed elaborately with the aid of optical and PL studies. The structure, composition and morphology of the samples were analyzed using XRD, XPS, FTIR, FESEM and AFM. The incorporation of F into SnO2 lattice is confirmed through FTIR analysis. (C) 2017 Elsevier Ltd. All rights reserved.