Breaking the RET barrier using Metamaterials

by Rahul Deshmukh (CUNY, USA)
21st December (Thursday) @ 5:00 PM

 

Phase Behavior and Dielectric Relaxation of Binary Mixtures of RDC

by Girish Chandra (SPS, JNU)
22nd December (Friday) @ 5:00 PM

 

Dewetting of solid films: Triple line kinetics and mass shedding

15th December (Friday) @ 5:00 PM
By Dr. Ashwani K. Tripathi(SPS, JNU)

 

Topological Order in Quantum Matter

by Prof. Subir Sachdev
(Harvard University, Cambridge)

20th November (Monday) @ 3:00 PM

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Welcome to SPS Journal Club

22nd Dec (5:00 PM) : Journal Club Physics Talk

'Phase Behavior and Dielectric Relaxation of Binary Mixtures of Rotationally Disordered Crystals'

Speaker: Girish Chandra

Position: Doctoral Student

Affiliation: SPS, JNU

Date: 22nd Dec, 2017 Time: 5:00 PM
Venue: Seminar Hall, SPS

Abstract : An especially challenging problem is the understanding of the glass transition with its tremendous but continuous slowdown of molecular dynamics when approaching the glass state. For that, the study of relaxation processes and phase behavior of orientationally disordered (or plastic) crystals is very advantageous since these materials involve only rotational degree of freedom. This makes much simpler to treat in theoretical and simulation approaches of the glass transition, and therefore these materials are often considered as model systems for structural glass formers. In this talk, we will discuss the Differential Scanning Calorimetry (DSC), Dielectric spectroscopy and X-ray results for binary mixtures of Neopentanol (NPOH) with tert-Butyl chloride (TBC) and Carbon tetrachloride (CTC), and try to understand the relaxation behavior of NPOH. The experimental results indicate the formation of the solid solutions. The crystalline solid thus formed is found to be orientationally disordered and supercools easily to form glassy crystal for mole fraction of NPOH in the range of 0.7 – 0.9. In the dielectric study, a primary α-process and two sub-T g processes are found for TBC-NPOH binary system, whereas for CTC-NPOH binary system only one sub-T g process is found.

 

 

 

21st Dec (5:00 PM) : Journal Club Physics Talk

'Breaking the RET barrier using Metamaterials'

Speaker: Rahul Deshmukh

Position: Doctoral Student

Affiliation: The Graduate Center, City University New York, USA

Date: 21st Dec, 2017 Time: 5:00 PM
Venue: Seminar Hall, SPS

Abstract : Resonance Energy Transfer (RET) between molecules is perhaps most famously known for its use in determining molecular structures. It is a direct interaction between two dipoles/molecules and its efficiency is governed by the distance between the molecules. This precise distance dependence makes it a very convenient ‘ruler’ for biologists but it’s useful in measuring distances of only up to 12-15 nm. Extending this range would be great, not only from the point of view of being able to study supermolecular assemblies, but also in photovoltaics where increased RET efficiency can greatly improve artificial light harvesting and energy storage. I will discuss our work in breaking this barrier using metamaterials – a class of composite man-made materials with novel properties that can be easily tuned to suit our requirements. We exploit this tunability and show RET between a donor-acceptor pair separated by a distance of 160 nm.

 

 

18th Dec (5:00 PM) : Journal Club Chemistry Talk

'Biophysical insight into the heparin‐peptide interaction and its modulation by a small molecule'

Speaker: Neha Tiwari

Position: PhD Student

Affiliation: SPS, JNU

Date: 18th Dec, 2017 Time: 5:00 PM
Venue: Seminar Hall, SPS

Abstract : The heparin‐protein interaction plays a vital role in numerous physiological and pathological processes. Not only is the binding mechanism of these interactions poorly understood, studies concerning their therapeutic targeting are also limited. Here, we have studied the interaction of the heparin interacting peptide (HIP) from Tat (which plays important role in HIV infections) with heparin. Isothermal titration calorimetry binding exhibits distinct biphasic isotherm with two different affinities in the HIP‐heparin complex formation. Overall, the binding was mainly driven by the nonionic interactions with a small contribution from ionic interactions. The stoichiometric analysis suggested that the minimal site for a single HIP molecule is a chain of 4 to 5 saccharide molecules, also supported by docking studies. The investigation was also focused on exploiting the possibility of using a small molecule as an inhibitor of the HIP‐heparin complex. Quinacrine, because of its ability to mimic the HIP interactions with heparin, was shown to successfully modulate the HIP‐heparin interactions. This result demonstrates the feasibility of inhibiting the disease relevant heparin‐protein interactions by a small molecule, which could be an effective strategy for the development of future therapeutic agents.

 

 

Recent Publications from SPS

 

 

Finite-Range Coulomb Gas Models of Banded Random Matrices and Quantum Kicked rotors.

A. Pandey*, Avanish Kumar*, S. Puri*

Phys. Rev. E 96, 052211 – Published 16 November 2017

 

 

Experimental study of relaxation dynamics in solid solutions of benzene, hexa-substituted benzenes. I

Abhishek K. Singh*, S.S.N. Murthy*

Thermochimica Acta, 657,  98-103 – Published 10 Nov 2017

 

 

Experimental study of relaxation dynamics in solid solutions of benzene, hexa-substituted benzenes. II

Abhishek K. Singh*, S.S.N. Murthy*

Thermochimica Acta, 657,  86-97– Published 10 Nov 2017

 

 

Appending Diverse p-Extended Acceptors with TTF Donors: Multistate Redox, Radical Ion Generation and Mid-IR Absorbing Mixed-Valence States

Sudhir Kumar Keshri*, Deepak Asthana*, Sonam Chorol*, Yogendra Kumar*, P. Mukhopadhyay*

Chemistry – A Europian Journal, Accepted online: 27 Oct 2017

 

 

Effect of Cu2+ substitution in spin-orbit coupled Sr2Ir1−xCuxO4: Structure, magnetism, and electronic properties

Imtiaz Noor Bhatti*, R. S. Dhaka, A. K. Pramanik*

PHYSICAL REVIEW B 96, 144433 (2017) – Published 26 Oct 2017

 

 

First graphene oxide promoted metal-free nitrene insertion into olefins in water: towards facile synthesis of activated aziridines

Prashant Shukla*, S. Mahata, A. Sahu, M.  Singh, V.K. Rai, A. Rai*

RSC Adv., 2017,7, 48723-48729 -Published 17 Oct 2017

 

 

Ordering kinetics in the random-bond XY model

Manoj Kumar*, S. Chatterjee, R. Paul, and Sanjay Puri*

Phys. Rev. E 96, 042127 – Published 16 October 2017

 

 

Biophysical insight into the heparin-peptide interaction and its modulation by a small molecule

Neha Tiwari*, Ankit Srivastava*, Bishwajit Kundu, M. Munde*

J. Mol. Reco. - Published 29 September 2017

 

 

Effect of T·T Mismatch on DNA Dynamics Probed by Minor Groove Binders: Comparison of Dynamic Stokes Shifts of Hoechst and DAPI

Him Shweta*, M. K. Singh*, Kavita Yadav*, Sachin D. Verma*, Nibedita Pal*, Sobhan Sen*

J. Phys. Chem. B, Article ASAP - Published 18 Sept 2017

* Authors from SPS