Archive-Mashelkar Endowment Lectures (May 2011-Jan 2015) Sr No. Date Speaker Name Title and Abstract 1 30-May-11 Prof. Biman Bagchi Title: Single Molecular View of Biological Processes : Protein-DNAInteraction, Enzyme Kinetics and Kinetic Proof Reading Abstract : Complexity of biological processes often does not allow a molecular level understanding of important dynamical events. However, recent single molecule spectroscopic studies have revealed new and fascinating aspects of several age-old problems that motivated new theoretical developments. In this talk I shall discuss our recent work on several such important biological processes, namely (a) the mechanism of diffusion of a non-specifically bound protein along DNA in its search for the specific binding site, and (b) the role of enzyme fluctuations in enzyme catalysis and, (c) explicit role of water in enzyme kinetics, and (d) theory of kinetic proof reading or, theory of lack of errors in biological synthesis within cells. 2 16-Jun-11 Prof Yamuna Krishnan Title: Molecular DNA devices in Living Systems Abstract : DNA has attractive physicochemical characteristics such as robust thermal and hydrolytic stability. It also has desirable structural characteristics stemming from predictable and specific recognition properties that give rise to a highly regular helical structure which behaves as a rigid rod on length scales upto ~50 nm. Since these rigid rods may be welded together by complementary base-pairing, DNA is now taking on a new aspect where it is finding use as a construction element to build exquisitely complex architectures on the nanoscale. This field is called structural DNA nanotechnology. We have been interested in architecturally simple, yet functional DNA-based molecular devices. Using two examples, one of a rigid, DNA polyhedron and another that functions as a pH sensor I will illustrate the potential of DNA based molecular devices as unique tools with which to interrogate living systems. 3 18-Jul-11 Prof. Kalobaran Maiti Title: Novel magnetism in magnetic and non magnetic materials Abstract: Magnetism of a material depends on two objects; (i) magnetic moment and (ii) mediators that couple them. Almost all the magnetic materials consist of elements possessing partially filled f (rare-earths: Eu, Gd, Tb, Dy etc.) or d (transition metals: Fe, Co, Ni etc.) bands among the highest occupied energy bands. Small radial extension of f-orbitals in rare-earths makes them highly localized leading to finite magnetic moment and coupling occurs via the interaction of these moments with the conduction electrons. The d electrons have both; magnetic moment due to strong electron-electron Coulomb repulsion and itineracy that mediates magnetic coupling. Recently some materials found those exhibit ferromagnetism (Curie temperature ~ 600 K) although they do not contain magnetic elements. On the other hand, conduction electrons screen local moment in a magnetic material making it non-magnetic. I will present some of our high resolution photoemission results that help to explore the origin of such unusual effects. It appears that low density of vacancies/defects in small band gap semiconductors can lead to high temperature ferromagnetism due to disorder induced effects. In the reverse case, Kondo effect compensates the magnetic moment leading to the absence of magnetic order - this seems to be an universal effect in correlated electron systems. 4 19-Aug-11 Prof. Ashutosh Sharma Title: Self-organized Meso-Fabrication and Functionalities in Highly Confined Soft Materials Abstract : This talk will summarize the underlying physics and some of the challenges in selfassembly and self-organization on micro/nano scales in soft materials based on understanding and control of instabilities in small scale systems. I will illustrate the basic principles from our recent results on novel meso-fabrication techniques and the resultant functionalities in soft polymer films and surfaces. These techniques and functionalities include: (1) A novel microfluidic reusable adhesive where the energy of adhesion is increased by two orders, (2) Elastic Contact Instability of a soft solid film, where a variety of structures such as arrays of femto-liter beakers, pillars and channels can be formed, aligned and modulated in-situ by controlled movements of a stamp, (3) Controlled Dewetting of thin (5 nm-100 nm) polymer films under an optimal water-organix mix to produce arrays of nanolenses of tunable curvature, (4) Electric Field Modulation of Interfaces where a visco-elastic film can be patterned on a hierarchy of length scales by spatio-temporal modulation of the field, and (5) Electrospinning, Micro-molding and photolithography combined to produce multiscale carbon-MEMS structures. The major emphasis in all these techniques is to produce functional structures and interfaces with wide ranging applications. 5 16-Sep-11 Prof. Sandeep Verma Title: Structural Consequences of Defined Organization in Solution and in Solid State Abstract : Biological superstructures are conventionally generated via recruitment of nanoscopic components in a “bottom-up” approach. In this context, essential biological macromolecules such as proteins, nucleic acids, lipids and their constituents, have received considerable attention for the construction of self-organized ensembles, owing their potential to form hydrogen bonds and support other non-covalent interactions. We have been working in the area of structural signatures of metal-nucleobase interactions in the solid state and bioinspired aggregation of peptide/protein conjugates in solution. In this lecture, we will discuss the approaches adopted by us in studying organization of molecules and conjugates with help of crystallography as well as microscopic techniques or a combination of both. The application of such conjugates and self-organized structures will also be addressed. 6 14-Oct-11 Prof. Dhananjai Pandey Title: Isostructural Phase Transitions in Multiferroic Solid Solutions of BiFeO3 Abstract : The phenomena of magnetic and ferroelectric orderings have been generally regarded as “mutually exclusive” in oxide perovskites. The coexistence of the two phenomena with a coupling between the magnetic and ferroelectric order parameters in some magnetoelectric multiferroics has therefore evoked tremendous interest in recent years because of the interesting underlying physics and also the possibility of designing new generation sensor, actuator and memory devices. Amongst the various magnetoelectric multiferroics, BiFeO is the only compound which exhibits multiferroicity at room 3 temperature suitable for device applications. The purpose of this talk is to present some of our recent results on the occurrence of rare isostructural phase transitions in solid solutions of BiFeO with BaTiO and PbTiO that are responsible for two different exotic phenomena, 3 3 3 namely the magnetoelectric coupling and unusually large tetragonal distortion of the ferroelectric phase. 7 15-Nov-11 Prof. Dr. Peter H. Seeberger Title: Carbohydrate-based Nanotechnology Abstract: Carbohydrates in form of glycoconjugates decorate the surface of cells and are key to many important biological recognition events. The placement of well-defined, synthetic glycans on surfaces can be used for delivery, molecular imaging and sensing applications. Described is a host of nanostructures equipped with synthetic cell-surface carbohydrates. Nanoparticles, surfaces, metallo-dendrimers and supramolecular assemblies not only possess interesting structural but also electrochemical and fluorescent properties. These novel structures were applied to diagnostic and imaging applications in vitro and in vivo. Reported are also molecular logic operations using such nanostructures. In addition, the use of continuous flow reactors to produce large quantities of nanoparticles will be discussed. 8 28-Dec-11 Prof. Sanjay Rastogi Title: Disentangled ultra high molecular weight polyethylene from fundamental to technological development Abstract : Ultra High Molecular Weight Polyethylene (UHMWPE) having average molar mass greater than a million g/mol is an engineering polymer. Due to its light-weight, high abrasion resistance and biocompatibility it is used for demanding applications such as body armour, prostheses etc. At present, because of its high melt viscosity to achieve the uniaxial/biaxial properties in the form of fibers/films the polymer is processed via solution route where solvent is used to process 5-10 wt% of the polymer. In past several attempts have been made to process the polymer without using any solvent. However, compared to the solvent processing route the achieved mechanical properties were rather poor. Here we show that by controlled synthesis it is feasible to obtain UHMWPE that could be processed free of solvent to make uniaxial tapes and biaxial films having unprecedented mechanical properties, exceeding that of the solution spun fibers. We address some of the fundamental aspects of chemistry, physics, rheology and processing for the development of desired morphological features to achieve the ultimate mechanical properties in tapes and films in the polymer processed via solid-state, free of solvent. 9 16-01-2012 Prof. Devang. V. Khakhar Title: Dense Granular Flows: Rheology and Segregation Abstract : Granular materials (e.g., sand, gravel, cement, food grains, coal, fertilizer, catalyst pellets, pharmaceutical powders, etc.) flow in a liquid-like state under some conditions. The rheology of such flows is complex