Abstract: Photonic crystals have proven their ability to control the propagation of light in low-loss media. These are artificial periodic optical structures in which scattering from periodic media can strongly modify the dispersion of light. The fundamental property   of photonic crystals is their photonic bandgap, which is frequency-dependent and inhibits the propagation of light in that region. Realization of these properties is applicable in many optical devices such as low loss Bragg mirrors, optical filters, and optical switches. Due to the technological challenges in fabrication, they are suffering from backscattering and localization phenomena which occurred due to the unwanted impurities and defects in the fabricated samples. Recently, the topological phase of matter from solid-state physics has been adopted in photonic crystals, which may describe a new state of light propagation. It provides a robust path for it by reducing the effects of backscattering, unwanted impurities, and defects, etc. This presentation will explain the foundation of photonic crystals from one-dimension to higher-order, and also introduces the topological ideas in photonic crystals.

Speaker: Ankit Singh (RSS2018505, PhD Student)

Speaker: Anju Sharma (RSS2017504, PhD Student)

Date: 9th Sept 2021

Title: Insight into mystery of smell Sub-title: DeepOlf for predicting odorants and their interacting receptors.

Abstract: Sense of smell, governed by olfactory system, performs variety of functions like detection and perception of odors, building an illustration of our environment, avoidance of danger, inter-individual non-verbal communications, governs behavioural and emotional output. Olfaction transduction mechanism is triggered by the binding of odorants to the specific olfactory receptors (OR’s) present in the nasal cavity. Different odorants stimulate different OR’s due to the difference in shape, physical and chemical properties. We have developed, a deep neural network architecture DeepOlf, based on molecular features and fingerprints of odorants and ORs, to predict whether a chemical compound is a potential odorant or not along with its interacting OR is proposed. Odorant identification and Odorant-OR interaction was modelled as a binary classification through multiple classifiers. The evaluation of these classifier’s performance showed that the deep-neural network framework not only fits data with better accuracy in comparison to other classical methods (SVM, RF, k-NN) but also able to predict odorant-OR interactions more accurately. To our knowledge, this study is the first realization of deep learning ideas for the problem of odorant and interacting OR prediction. The accuracy of DeepOlf was found to be 94.83% and 99.92 % for the prediction of odorants and Odorant- OR interactions respectively. Comparison of DeepOlf prediction with the existing SVM based prediction server, ODORactor, showed that better performance can be achieved with the proposed deep learning approach.

Speaker: Subhodeep Sarkar (RSS2019005, PhD Student)

Title: The Fascinating Physics of Black Holes

Date: 9th Sept 2021

Abstract: In this talk, I shall try to convey some of the key ideas underlying the general theory of relativity and highlight one of its most astounding consequences, the existence of black holes. I shall retrace some of the major milestones that have shaped our understanding of black holes and touch upon some of the key issues that continue to be an area of active investigation. In particular, I shall talk about the internal structure of black holes and also address questions related to the detection of astrophysical signatures of black holes. Along the way, I will also mention some of the humble efforts made by workers here at IIITA towards addressing these problems.

Speaker: Pankaj Warbal (RSS2018502, PhD Student)

Title: Photoacoustic Tomography: A relatively new imaging modality.

Date: 16th Sept 2021

Abstract: In this talk, I will introduce the basic concepts of biomedical imaging. And then I will tell about photoacoustic tomography (PAT) which is my area of research. It is one of the recent imaging modalities still in the pre-clinical stage. PAT combines the advantages of optical (high contrast) and ultrasound imaging (penetration depth) techniques in a single modality. In photoacoustic (PA) imaging, the chromophores present inside the tissue absorb the light energy when irradiated by short laser pulses and results in the generation of wide-band acoustic waves. This is because of the rapid thermo-elastic expansion of the illuminated region. This is known as the PA effect. These acoustic waves (or PA signals) are captured using ultrasound detectors placed around the illuminated tissue. The recorded signals are then processed to generate the map of the initial pressure distribution. This is called image reconstruction. The algorithms used for image reconstruction can be analytical (like back-projection, time-reversal) as well as model-based (like Tikhonov regularization). With the help of IIIT-A administration and the Department of Applied Sciences, we have established a Biomedical Imaging Laboratory (BMIL). The laboratory has the facility of PAT imaging and other experiments of PA signal calculation and characterization. We also have a separate room for biology experiments where sample preparation and storage will take place. I will show some of the experimental results generated in our laboratory.

Speaker: Amar Dhwaj (RSS2018007, PhD Student)

Title: Biomimetics and 3D printing in Tissue Engineering

Date: 16th Sept 2021

Abstract: Rapid prototyping in the tissue engineering field has now become the important integral part which is used to develop various biomaterial based tissue scaffolds. Unlike the conventional methods, the rapid prototyping is based on 2D/3D Computer Numeric Control (CNC) based systems. Nowadays the most prevailing challenge is to find an organ Donor for the patients with the specific organ type in order to eliminate histocompatibility issues with the donated organs. Other than complete organ donation, patients with third degree burns require immediate skin transplant. Several remedies for severe burn patients are available in the market which are artificially derived skin grafts. Conventional methods involve Solvent casting and particulate leaching, melt molding, gas foaming, freeze drying and fiber bonding etc. Steps involved in the fabrication of tissue scaffolds with the conventional methods are very lengthy and time taking and also requires expertise and experience to achieve a desired microstructure. Rapid Prototyping on the other hand requires the Computer Aided Designing (CAD) skills to fabricate a tissue scaffold and microstructures. The parameters like Porosity, scaffold morphology, scaffold topography and Bioactivity, etc. can be easily adjusted during the CAD modeling itself. Here we are going to develop a versatile 2D/3D (CNC) based build platform which can perform multiple 2D/3D(CNC) based operation like Laser based ablation/engraving, Laser based patterning, Liquid polymer patterning, milling based operations, 3D patterning on a single platform with different Biomaterials in order to fabricate 2D/3D tissue scaffolds. Fabrication process will be done using different biocompatible polymers like PLA (Poly Lactic acid), PCL (Poly Caprolactone), PEG (Poly-ethylene Glycol), Collagen, and Chitosan, etc. and will be subjected to further biological testing using different mammalian cell lines including Hepatic cell lines, Cardiomyocytes, and Epithelial Skin cells, etc.