Browse
Recent Submissions
Publication Earth Abundant Manganese Catalysed Sustainable Chemical Transformations(Indian Institute of Technology, Jodhpur, 2025) Chakraborty, SubrataThe growing interest in Earth-abundant transition metals for organometallic catalysis stems from their economic advantages, availability, and unique catalytic properties. Manganese, the third most abundant transition metal in the Earth's crust, has emerged as a promising alternative to precious metals such as platinum, palladium, and rhodium, which are commonly used in catalytic processes like (de)hydrogenation, hydroboration, hydrosilylation. While precious metal catalysts are renowned for their high activity and robustness, their high cost and limited availability pose significant challenges. In contrast, manganese offers a more sustainable and cost-effective option, though it often requires more advanced catalyst design to match the performance of precious metal-based systems. Manganese catalysts are typically designed around three key principles: metal–ligand bifunctionality, ligand hemi-lability, and redox activity. By optimizing these factors, manganese catalysts can be engineered to achieve competitive turnover numbers, although they may not always match the efficiency of precious metals in certain applications. This thesis provides a comprehensive analysis of the catalytic properties of manganese complexes, comparing their activity, versatility, and efficiency in the direction of alkylation, (de)hydrogenation, deamination and hydration reactions. It also highlights the critical challenges in manganese catalyst design, particularly in ligand optimization, and offers insights into how these catalysts can be improved for broader catalytic applications.Publication Flexible Organic Transistors with Natural Materials For Eco-friendly Electronics(Indian Institute of Technology, Jodhpur, 2025-01-08) Tiwari, Shree ParkashContinuous development of technologies over time has significantly shortened the lifespan of devices, resulting in a substantial increase in electronic waste (E-waste) causing negative impact on environment and ecology. Flexible electronics has emerged as promising technology towards offering solution to this issue by capability of incorporation of nature originated materials in device fabrication through instilling eco-friendliness and potential biodegradability. Organic field-effect transistors (OFET) have been widely investigated as crucial device component for flexible electronics due to its applicability in circuit, sensing, and memory applications. This thesis is an effort to contribute towards flexible biodegradable electronics. Specific emphasis was given on the demonstration of eco-friendly OFETs for circuit and sensing applications with multi-functionality and eventual decomposability, which are essential requirements for smart and sustainable electronics. To start with, various solution processed biocompatible or natural polymers including polyvinylpyrrolidone, silk fibroin, gelatin, chitosan, egg albumen, and cellulose derivative were explored as promising gate dielectrics in OFETs, either as single layer or in bilayer combination with other polymers or a thin high-k hafnium dioxide (HfO2). All these devices were fabricated on indium tin oxide (ITO) coated glass or polyethylene terephthalate (PET) substrate, where ITO acting as bottom electrode. Widely explored pristine TIPS-Pentacene or TIPS-Pentacene: Polystyrene (PS) blend was utilized to form active layer with gold (Au) top electrodes working as source/drain, to demonstrate p-channel transistor characteristics for -5 V operation. Low voltage operation (-3 V) in flexible OFETs was demonstrated using a pristine layer of solution processed gelatin in combination with TIPS-Pentacene: PS blend. These devices exhibited excellent electrical characteristics with extracted field-effect mobility (μ) value approaching to as high as 3.0 cm2 V-1 s-1 with near-zero threshold voltage and low subthreshold swing (SS), along with remarkable operational stability as confirmed by various stability tests including bias-stress, repeatability, cyclic, bending and long-term ambient stability. A very high environmental stability over 24 weeks was observed with almost unchanged electrical characteristics. Circuit applicability of these devices was successfully demonstrated through resistive load inverters. Multifunctionality in OFETs with gelatin/HfO2 hybrid bilayer gate dielectric and TIPS-Pentacene as semiconductor was demonstrated with multi-parameter sensing capabilities for visible/UV light and humidity, which also led to real time breath rate monitoring, a simple tool for wellness monitoring. Maximum field-effect mobility (μmax) of 2 cm2 V-1 s-1 was exhibited with low SS value of ~200 mV/dec., and high current on-off (Ion/Ioff) ratio ~104 for -5 V operation with excellent electrical, operational, and bending stability. For the enhancement of performance and stability in devices with nature originated dielectrics, a composite of gelatin and chitosan was investigated with chitosan acting as a tuning agent to modulate the gate dielectric properties through controlled crosslinking facilitated by the electrostatic interaction and strong hydrogen bonding between the functional groups of polymers. Devices fabricated with a gelatin: chitosan ratio of 10:5 exhibited better electrical stability upon bending for 100 repeated bending cycles compared to other ratios. Circuit applicability, high bias-stress stability, and shelf life for 24 months indicated overall high performance using the composite gate dielectrics. Finally, devices were fabricated on paper substrate thorough process optimization for substrate planarization with polyvinyl alcohol (PVA), silver (Ag) as gate electrode, to move towards eco-sustainable electronics. Cyanoethyl cellulose (CEC), a synthesized version of cellulose was comprehensively investigated as a potential gate dielectric in OFET devices for eco-friendliness. Transistors with CEC dielectric and paper substrate were demonstrated in an effort to produce biodegradable systems for eco-sustainable electronics. These devices exhibited high performance with excellent saturation in the output characteristics for -5 V operation along with remarkable electrical and operational stability. High bendability of devices was confirmed upon application of tensile stress through bending along the channel for the bending radii of 12, 7, and 5-mm. Moreover, high cyclic stability was achieved in devices even after keeping the device in high humid environment with relative humidity reaching to ~100 %. High decomposability in water rich soil in ~20 days was observed due to the microorganisms present in soil environment, confirming excellent biodegradability which is highly essential for eco-sustainable electronics. Due to high performance and biodegradability, these paper-based devices can offer huge potential towards the future flexible and green electronics, and can help in minimizing the impact of E-waste on environment and ecology.Publication Design and Development of Disposable Microsystems for Sensing Applications(Indian Institute of Technology, Jodhpur, 0021-09-20) Gupta, AnkurSensing and diagnostics have become essential parts for our healthcare monitoring. Disposable microsystems can be potential solution for the same which are designed for single-use while eliminating the risk of cross-contamination between patients. These devices are typically aimed to design for straightforward, one-time use, simplifying the testing process and hence, are of low initial cost. Along with this, it addresses environmental concerns associated with single-use plastics. In this context, Paper-based analytical devices (PADs) are desgined and developed which are economical, recyclable, biocompatible, and robust. They consist of a network of hydrophobic and hydrophilic micro-channels which are capable to handle and quantitatively analyze the target analyte. There is no requirement for the clean-room facility to fabricate such device, and it does not require any external pump for the movement of target analytes. Paper strips have been used for several decades for biomedical assays because they provide a low-cost platform for colorimetric testing. Previously, Müller and Clegg reported the first kind of paper-based microfluidic device in 1949. However, the Whitesides group later explored paper-based microfluidics, and it opened new pathways in this field for the use of paper to develop portable, on-site detection in bio-sensing applications. This research investigates simple fabrication strategies for cost-effective mass manufacturing of disposable microsystems for sensing applications, while utilizing a leak-proof paper-based analytical device (PAD) by creating a hydrophobic zone through the proper penetration of ink into the pores of the paper. An inexpensive disposable colorimetric sensor developed through the assistance of chemometric reaction and tested for the optimization of samples and the determination of glucose for different concentrations (0.5-20 mM and 0.1-0.5 M) with a LOD of 2.92 mML−1. To increase platform's resistance to variations in illumination and camera optics, images taken with several cellphones in various lighting conditions were used to train classifiers, with an accuracy of 72.7%. To enhance the analysis platform’s robustness and make it user-friendly, the image data set was taken at various angles of incident light with an overall accuracy of~ 93%. Further, for the multiplexed detection of the analyte, a unique trident-shaped μPAD has been fabricated on a chemically modified A4 paper, followed by the theoretical and experimental fluid flow. Three different biomarkers, glucose, lactate, and uric acid, were detected through colorimetric enzymatic reaction on the novel trident-shaped disposable PAD, with LOD and coefficient of determination of 0.28 mM, and 0.98, 0.40 mM and 0.97, and 0.22 mM and 0.99) respectively. This platform achieves a high accuracy rate of analyte detection (~ 97%) in predicting three different colorimetric findings, both quantitatively and qualitatively through an Android application. The application's integrated image processing tools autonomously identify the region of interest (ROI) and minimize human error, enhancing the platform’s user-friendliness and precision. Proceeding the work, for the exploration of electrochemical sensing, a non-enzymatic electrochemical sensor was developed for the detection of lactic acid with a sensitivity of 0.00176 mA*μM-1cm-2 and LOD of 0.76 mM, followed by computation studies of reaction molecules.Publication Next Generation Routing and Data Dissemination Techniques for Vehicular Ad-hoc Networks(Indian Institute of Technology, Jodhpur, 2024-07-23) Das, Debasis; Das, Sajal K.Consider a driver on a busy highway where their vehicle immediately receives alerts about a collision occurring three cars ahead, well before it comes into their line of sight. Or imagine a navigation system dynamically rerouting the driver to avoid a newly formed traffic jam just a few kilometers away. This is the capability offered by Vehicular Ad-hoc Networks (VANETs), which enable direct communication between vehicles and roadside infrastructure, establishing a real-time digital network that enhances road safety and optimizes traffic flow. However, deploying VANETs is complex. On actual roads, particularly in developing countries, traffic is highly heterogeneous ranging from cars and buses to motorcycles and auto-rickshaws, all traveling at varying speeds, frequently changing lanes unpredictably, and constantly joining or leaving the network. Traditional communication protocols, originally designed for relatively stable and homogeneous networks, struggle under these conditions: communication links frequently break, message flooding occurs in dense traffic scenarios (known as "broadcast storms"), and critical safety messages that require delivery within 100 milliseconds often fail to meet the stringent latency requirements. This thesis addresses these fundamental networking challenges (packet routing) by developing and validating next-generation routing and data dissemination techniques that maintain reliability despite high node mobility and diverse traffic conditions. Our contributions encompass three different directions: direction-aware forwarding mechanisms,metaheuristic-based clustering frameworks, and hypergraph-based communication models. We first propose three orientation-informed routing protocols, Cosine Similarity-Based Routing (CSBR), Orientation-Based QoS Routing (OBQR), and SDCast leveraging vehicles’movement direction and road context to improve data dissemination. Unlike conventional broadcast or shortest-path schemes, these protocols dynamically bias message forwarding along the direction of traffic flow, reducing redundant transmissions and avoiding relays on vehicles that are likely to move out of range. In CSBR, a cosine similarity metric between vehicle velocity vectors is used to select relay candidates, ensuring that only vehicles with aligned directions participate in rebroadcasting. OBQR builds on this by incorporating multi-constraint QoS metrics (link stability, transit delay, etc.) into routing decisions, using a weighted optimization to find routes that honor safety-critical latency and reliability requirements. Finally, SDCast introduces a hybrid Software-Defined Networking (SDN) architecture into the VANET: a two-tier controller system (a central controller working with local Roadside Units) that orchestrates cluster-based forwarding policies. To improve communication stability and QoS in dynamic conditions, we next develop advanced clustering and routing optimization techniques using metaheuristics. Two frameworks, i.e., MetaLearn and Multi-constraint Routing using Hybrid Metaheuristics (MRMH) are introduced to intelligently organize vehicles into semi-stable clusters and optimize multi-hop routes within and between these clusters. MetaLearn employs a hybrid learning approach: it uses meta-heuristic algorithms (Grey Wolf Optimization (GWO)) to bootstrap efficient clustering, and then applies reinforcement-learning principles (fast adaptation based on prior outcomes) to continually refine routing policies as conditions change. This enables the routing strategy to “learn” from the network’s behavior, quickly adapting to recurring traffic patterns (e.g., rush hour flows) and thereby improving long-term performance. MRMH, on the other hand, hybridizes multiple optimization techniques (GWO and Sequential Quadratic Programming (SQP)) to solve the routing problem under multiple constraints (such as latency, link durability, and bandwidth) simultaneously. By hybridizing metaheuristics methods, MRMH avoids the pitfalls of single-metaheuristic approaches (like premature convergence or high computational cost) and finds high-quality routes that satisfy all QoS requirements even as the network scales. Finally, we present an approach using Spatio-Temporal Information-Aware Hypergraph formulation that generalizes the traditional network graph model to a hypergraph structure. In a hypergraph, an edge (now called a hyperedge) can connect any number of vertices, which in our context means a communication event can directly involve multiple vehicles. This representation is paired with a deep learning-driven routing strategy that uses spatial (geographic/positional) and temporal (time-dependent) dynamics of vehicles and network conditions to make optimized decisions. By capturing higher-order relationships (beyond simple pairwise links) and feeding them into a deep learning algorithm, the network can better anticipate and adapt to changes. Further, we introduce a Software-Defined Fog Computing (SDFC) framework for VANETs,which pushes computational intelligence and control closer to the network edge (the vehicles and roadside units). This enables data processing and decision-making to occur in proximity to where data is generated. By doing so, fog computing can drastically reduce end-to-end communication delays and offload traffic from the core network. In our SDFC framework, VANET management functions (such as cluster formation,routing control, and load balancing) are distributed across a hierarchy of cloud, fog, and edge layers. This design improves scalability and reliability by avoiding single points of failure and by adapting to local conditions. To ensure experimental validations, all proposed techniques were implemented using standard VANET simulation tools and real hardware. Simulations leveraged frameworks like NS-2/NS-3 and OMNeT++ (with the Vehicle in Network Simulations (VEINS) open source library) for network-layer behavior, standard Vehicle-to-Everything (V2X) communication technology (IEEE 802.11p, Cellular-V2X) and Simulation of Urban Mobility (SUMO) for generating realistic vehicle mobility on road layouts imported from OpenStreetMap (openly-licensed data from national mapping agencies and other sources). We seeded simulations with actual city road maps and traffic patterns (including heterogeneous vehicle types, intersections and traffic lights) to closely mirror real-world conditions. Key performance metrics, end-to-end latency, packet delivery ratio, routing overhead, cluster membership time, throughput, and route discovery time were measured across a range of scenarios (urban environments, highways, varying vehicle densities from sparse to congested). Furthermore, the algorithms were tested on a physical testbed: our Duckietown setup (miniature autonomy test bed) and anedge computing platform with Raspberry Pi and JetsonNano devices (working as Onboard Units and Roadside Units) allowed us to verify that the protocols run within real-time constraints on resource-constrained hardware.Publication Xurography- Based Microfluidic Platform for Mimicking Neuronal cytoarchitecture and Exploring its Application in Neurodegenerative Disease Research(Indian Institute of Technology, Jodhpur, 2025-01-03) Ghosh, SurajitThe brain is an intricate system composed of millions of neural networks. Deciphering its overall dynamics and the underlying significance of several cues that direct neuronal development, the formation of axons, dendrites, and synapses during wiring and re-wiring remains a formidable challenge in developmental and cellular neuroscience. Although traditional in vitro macroscopic cell culture techniques are easy to perform, they often fail to mimic the complex phenomenon of brain microenvironments. Recent advancements in microfluidic device-based cell culture technologies have successfully overcome the limitations of conventional cell culture methods, enabling the reconstitution of neural cytoarchitecture through precise spatiotemporal regulation of compartmentalized cell culture microenvironments. These lab-on-chip technologies can aid in elucidating the fundamental principles of brain function and provide innovative platforms for screening neurotherapeutics. This thesis offers a succinct overview of the structural and functional aspects of the human nervous system by the reconstitution of the central and peripheral nervous systems on the chip. It highlights the neurological disorders associated with dysfunctions in both systems. It also reviews the several strategies researchers have adopted to mimic neurogenesis on a chip. Additionally, we have designed and developed an economical, innovative microfluidic device utilizing a state-of-the-art Xurography technique. Thereafter, we performed on-chip cell culture studies with primary neurons and SH-SY5Y cells to validate the cytocompatibility of the device. Furthermore, we demonstrated the application of the fabricated device as a coculture model using astrocytes and neurons. The device also served as a drug screening platform for a multi-targeted compound in the differentiated SH-SY5Y cells in the context of Lastly, we also developed a Ferroptosis model that can be linked to neurodegenerative disorders. In this regard, we also investigated the efficacy of a synthesized small molecule inside our fabricated microfluidic device. All these lead to the conclusion that our simple and cost-effective Xurography-based microfluidic device can open gateways to decipher neuronal events inside the human brain and serve as potential platforms for neurodegenerative disease modelling and screening novel therapeutic agents.Publication Studies on Beam Steerable Dipole Antenna(Indian Institute of Technology, Jodhpur, 2025-02-01) Yadav, Sandeep Kumar; Mukherjee, SoumavaHF communication using sky wave propagation through ionosphere plays a vital role for short and long distance communication specially in the fields of Defence, maritime role, police and remote sensing. For reliable and efficient HF communication various adaptive data transmission schemes have been formulated. This require selection of best channel frequency through ALE (Automatic Link Establishment) and choosing of best modulation to provide highest possible bit rate. Optimum deployment of HF antenna after predicting accurate frequency spots for real-time communication at various ranges is essential due to HF link limitation of impulsive atmospheric noise, multipath propagation, limited band width and interference. However, changes in HF dipole antenna height with respect to range and time was still needed to be addressed. Height of HF antenna above ground plays a vital role for establishing successful HF contact. Effective HF communication is dependent on accurate radiation / take off angle achieved by the transmitting antenna. The height of HF antenna to be adjusted either while variation of frequency during different time slots or variation of distance between transmitting and receiving stations. Desired radiation / take of angle can be achieved by adjusting the antenna height above ground while variation of operating frequency during different time slots i.e. Day, Night, Transition1 and Transition2. The variation in take of angle is maintained by modifying the radiation pattern of the antenna by changing the height or other critical dimensions of the antenna system. Several techniques are being adapted for variation of antenna height e.g. mechanical/physical variation of the antenna height, deployment of various height of multiple HF Antenna at different time slots etc. These methods require additional infrastructure and assets resulting in enhancement of time, cost and complexity. To address this limitation, a beam steerable inverted V HF dipole antenna has been proposed in thesis as an effective solution for beam steering of HF antenna without changing antenna height. To provide adequate beam steering a reactive circuit with parallel variable capacitor and inductor has been positioned at one end of dipole. Tilting of antenna pattern has been controlled by variable capacitor keeping fixed value of parallel inductor. Continuous beam steering of 60 degree (± 30 degree) has been achieved by changing the capacitive value from 26.6 PF to 27.7 PF at 9.3 MHz frequency by adjusting the Capacitor biasing voltage from 1.24 V to 1.10 V. The present work provides novel technique for electronically adjusting radiation beam take off angle to maximize HF coverage throughout the elevation plane with no variation in physical height of HF antenna. The steering of ± 30 degree beam takes off angle has been achieved electronically without varying physical height of HF antenna. In thesis, an efficient solution for selection of HF frequencies along with optimum deployment of antenna system for various ranges has been proposed. The optimum HF prediction presented in previous works provides contours of the probability of successful HF transmission as a function of frequency and time of day which presents means for HF spectrum utilization, giving a probability number to any assigned frequency at a given time of day. However external environment strongly influences HF communication frequencies due to variation of ionosphere layers along with variation of time as well as environmental changes. Therefore, it is not always feasible to change the height of antenna with variation in time. Present work considers different sets of frequencies at four different time slots and subsequently selection of frequencies carried out based on maximum usable frequency (MUF), frequency of optimum traffic (FOT) predicted from HF prediction software. The proposed work provides efficient solution for finding out optimum frequencies during various time slots and HF antenna height estimated accordingly for different path lengths. Based on linear approximation between effective antenna height and frequency of operation, a new set of equations has been proposed in thesis which can directly be used to calculate effective height of the HF antenna for all distances between transmitting and receiving stations during various ranges of HF communication. Various past research work with respect to HF frequency tuning focuses on either electrically small antennas or narrow band, dual band frequency tuning. However long-range wide band HF antenna frequency tuning needed to be addressed. In the thesis, a frequency tunable HF antenna with feeding network modification technique has been proposed to vary the long range inverted ‘V’ HF dipole antenna resonant frequency while maintaining the fixed dipole length. With the implementation of feeding network modification technique most of day/night frequencies can be covered in a particular time slot resulting in highly effective and accurate HF contact with least variation of antenna height. Resonance frequency shifting (3 MHz) from 7.5 MHz to 10.5 MHz has been demonstrated with gain of 5.4 dB by varying length of feeding network for 10 MHz inverted ‘V’ HF dipole antenna. Extensive trials were conducted to validate the performance results and same found as desired. Open Space radiation pattern measurement of wide band HF dipole antenna is a cumbersome process due to its long dipole length in meters and possible usage of Unmanned Arial Vehicle (UAV) or airborne object based systems for antenna measurements. This is a complex and expensive setup. To verify the concept of proposed beam steerable HF antenna, a low cost, small form factor model at ISM band has also been proposed as beam steerable printed dipole antenna. The radiation pattern of beam steerable printed dipole antenna has been measured and same concept can be extended to beam steerable HF antenna also. Hence, there was a need to study on novel approaches to design beam steerable antenna for different operating frequency with reduced complexity. Similar to design topology of inverted V HF antenna, a small form factor model as beam steerable inverted V printed dipole antenna has been proposed in thesis using single dipole integrated with a varactor diode and parallel inductor in one arm of antenna. Most of previously fabricated electrically tuned antennas requires more than one dipole and multiple tuning elements mounted on common platform for scanning between two angles / switching at different elevation angles. Proposed Planar Inverted V Dipole Antenna is capable of continuous beam steering (± 30 degree) electronically using Single Printed Dipole and single varactor diode. Hence, resistive and parasitic losses of proposed antenna is considerably low along with low design cost and the least space requirements. Steering angle for antenna radiation pattern has been controlled by gradually varying the capacitance value keeping fixed value of parallel inductance. Required biasing circuit for varactor diode is intentionally placed on substrate at back side of dipole arm to avoid losses. Antenna gain for proposed design observed to be 4.1 dB with less than 1 dB scan loss and cross-pol well below -25 dB. The antenna is capable of steering beam ± 30 degree in elevation plane at 2.35 GHz by tuning varactor diode bias voltage to achieve various capacitance values. Beam steerable printed antennas are useful for various applications e.g. mobile communication, Internet of Things (IoT) application, vehicular communication, sensor etc. For such applications large phased array or reflect array antennas are less suitable in comparison to compact planar tunable antennas. Several designs topologies have been proposed to achieve beam steering using phase shifter, varactor diode and PIN diode-based feeding network. However, such circuits have limitation of high parasitic loss, high insertion loss and space complexity. A digitally controlled beam steerable printed dipole antenna operating in Industrial, Scientific, and Medical (ISM) band has been proposed at 2.45 GHz operating frequency with 120 MHz bandwidth and 4.57 dB max gain using PIN diodes switching mechanism. The fabricated antenna provides effective solution of beam steering by establishing adequate coverage in elevation plane using a single dipole element. The beam steering of antenna has been digitally controlled by varying the effective length of one dipole arm by switching the PIN diodes integrated on it. For effective digitally controlled beam steering, the DC biasing voltage applied for switching PIN diodes is regulated by Pulse Width Modulation (PWM) signal generated from microcontroller through RC filter. Biasing elements for antenna is intentionally placed on back side of substrate through via to minimize the effect on radiation pattern. The proposed antenna is capable of steering beam up to 45 degrees in elevation plane. The present method eases the fabrication and measurement setup. However, the concept can be rescaled to other frequency of interest including HF communication for conventional HF horizontal dipole antenna. The proposed work in thesis will definitely enhance the efficiency of short and long range communication, especially in the field of HF communication to provide a novel platform for optimum deployment of HF antenna ensuring the high operational efficiency of defense and other strategic fields of national security.Publication Calix[4] arene Derived Catalysts for Asymmetric Organic Transformations(Indian Institute of Technology, Jodhpur, 2024-09-06) Sharma, Rakesh KumarThis study draws attention to supramolecular catalysts. Cram, Lehn, and Pedersen’s pioneering works evolved around the use of supramolecules for molecular recognition and catalysis. Supramolecules offer defined binding pockets and noncovalent interactions such as hydrogen bonding, van der Waals forces, and π-π interactions, thus generating a reaction microenvironment for catalysis. Moreover, macrocycles can provide a preorganized arrangement of functional groups, such as binding sites or catalytically active groups, thus enabling a defined and possibly multivalent binding and activation of substrates. Various supramolecules such as calixarene, cryptands, cucurbiturils, and COFs, have been studied for a variety of applications for environmental and catalytic applications. Among various supramolecules, calixarene is the most important molecule for constructing conformationally rigid supramolecular catalysts. The unique properties of calix[4]arene lead to a rational design of homogeneous catalysts and due to the absence of metals, these methods are attractive for the preparation of pharmaceutical compounds, and chemical reactions that are of high value in the biological, and chemical industries. With the increasing demand for chiral products, many efficient catalysts have been developed for a wide range of organic transformations. The major part of asymmetric catalysis is homogeneous catalysts as they facilitate molecular reactions in an efficient manner with high chirality transfer. Calix[4]arene appended catalysts are easily recoverable, separable, and can be purified as well and these catalysts could be recycled with a good number of recyclable cycles. Out of various studies on asymmetric homogeneous organocatalyzed reactions, asymmetric Michael addition of acetylacetone to β-nitrostyrene is one of the key reactions with wide applications in pharmaceutical industries. Mono and dicationic Cinchona alkaloid-anchored calix[4]arenes as organocatalysts were effective and gave high enantiomeric induction (∼99% yield and >99% ee). Phase Transfer catalysts (PTC) based on calixarene supramolecules offer special advantages due to their unique properties with a rigid and stable aromatic cavity. Additionally, four phenolic hydroxyl groups of calix [4] arene provide synthetic adaptability and noncovalent interactions and a new catalyst designed utilizing quaternary ammonium Cinchona-functionalized crown ether-strapped calix[4]arenes as PTCs for asymmetric α-alkylation of glycine imines to α-alkylated glycinates with remarkable selectivity under ambient conditions (∼98% yield and >99% ee). Another PTC designed a highly selective α-methylbenzylamine functionalized crown-ether-appended calix [4]arene is harnessed for asymmetric nitroaldol reaction to provide nitroaldol adducts in high yields (up to 99 % yield) with good to excellent enantioselectivities (up to 99.8 % ee). Organocatalysis has gained noteworthy attention due to its efficiency, selectivity, and gratifying results at sub-stoichiometric amounts of the chiral catalyst and calixarene-derived enantioselective organocatalytic one-pot Strecker reaction catalyzed by camphor sulfonyl functionalized crown-ether-tethered calix [4] arene and provide the desired cyano adducts in high yields up to 99.9% yield and 99.2% ee. The synthetic utility of the Strecker reaction was used in the synthesis of Clopidogrel.Publication Flexible Resistive Memory Devices for Eco_friendly Electronics: Fabrication, Modeling, and Circuit Implementation(Indian Institute of Technology, Jodhpur, 2025-06-20) Tiwari, Shree ParkashThe domain of flexible electronics has experienced an unprecedented rise in research and development activities, owing to its wide applications such as wearable devices, flexible displays, and sensors for biomedical purposes. This has motivated researchers to actively explore a suitable flexible memory device for storing the data generated or received by the flexible electronic circuit(s), to achieve monolithic integration i.e., fabrication of different flexible devices on the same substrate. Resistive random access memory (RRAM), a two terminal metal-insulator-metal structure device, with its various advantages such as ease of fabrication, low cost, high speed, ease of integration, and high scalability has emerged as a promising memory device for flexible electronic systems. Moreover, in view of ever increasing electronic waste, nature originated materials are being explored for the fabrication of different organic devices, and flexible electronics provide an added advantage of incorporating the organic materials in fabrication process, as most of these materials have properties such as solution processability and mechanical flexibility, along with non-toxicity, biocompatibility, and biodegradability which further instill eco-friendliness in devices. In this work, initially, natural proteins gelatin and egg-albumen, were investigated separately as a switching layer of RRAM devices. The prepared solutions of gelatin and albumen were deposited on the Indium-doped tin oxide coated polyethylene terephthalate substrate, and silver was used as the top electrode. The fabricated flexible RRAM devices with gelatin switching layer, have exhibited excellent switching behavior with Ion=Io f f ratio of greater than 105 and retention time of more than 104 seconds. Similarly, the albumen switching layer devices have also shown excellent resistive switching with high current on/off ratio of around 105 and memory retention time of 103 s without showing relevant degradation. The devices were then subjected to a mechanical bending of radius 7.5 mm, and it was observed that the device maintained the memory window of greater than 103 for more than 103 seconds. These results suggested that these organic proteins should further be explored for fabrication of flexible organic memory devices. Furthermore, to enhance the multiple cycle switching (endurance) of the devices, these proteins were investigated in hybrid bilayer combination with an ultrathin (5nm) layer of HfO2 as switching layer. Hybrid bilayer Ag/Gelatin/HfO2/ITO devices have shown a very high memory window of greater than 105 and data retention of 104 s without any degradation in a pristine state. Moreover, after bending the devices at a 12 mm radius followed by 7 mm, it was observed that the devices have maintained the memory window of 105 without any degradation in data retention, indicating excellent electromechanical stability of the devices. Similarly, Ag/Albumen/HfO2/ITO devices have demonstrated excellent switching characteristics with a current on/off ratio of greater than 104, stable retention of both low resistance and high resistance states, reliable multiple cycle switching, and very low switching power (with set power as 0.5 mW and reset power as 3.1 mW). The devices have also shown excellent electro-mechanical stability, with bending radii of 7.5 mm, 5 mm, and 2.5 mm. Additionally, to enable simulation based study of the fabricated device, a mathematical model of RRAM device has been studied and investigated. The model is then calibrated with the median of experimental results to extract the values of fitting parameters with less than 5% rms error. This ensures that the model can be utilized to simulate the switching characteristics of the fabricated device with greater accuracy. The model was further improved by introducing parameters for multiple layers of insulator, and multiple cycle variation parameters to make the model more robust. This improved RRAM model was then utilized to design a simple flexible hybrid electronic (FHE) circuit that is capable of generating 4 bit random numbers by utilizing intrinsic randomness of the device. The circuit is designed with 65nm technology node and the RRAM model with cyclic variation is utilized as the source of entropy. To verify the randomness of the proposed FHE circuit, the generated outputs have been test with NIST SP 800-22 test suits, a widely accepted set of tests to verify randomness of a bitstream. The outputs of this circuit have passed all the applicable tests of NIST SP 800-22, indicating the presence of randomness. This not only represents taht the output bitstreams are random in nature but also reflects that the improved model is capable of taking care of cyclic variations to a larger extent. Recently, Pectin was extracted from orange peel, and utilized as a switching layer. The fabricated flexible devices have demonstrated good resistive switching behavior with high current on/off ratio of 104 and retention time of 103 seconds. The fabricated device has then been investigated for synaptic behavior, probably for the first time, and it demonstrated depression characteristics with 10 ms input pulse, and the PPF relaxation time constants t1 = 0.3 ms and t2 = 4.1 ms are obtained. The results show a similar trend as that of a biological synapse, and thus it may be concluded that the fabricated device with pectin can be utilized for neuromorphic applications.Publication Valence, Archetypes, and Reciprocity in Wise Negotiation(Indian Institute of Technology, Jodhpur, 2025-01-03) Sharma, AnkitaNegotiation is an essential aspect of daily life and a critical tool for achieving success across various domains, from interpersonal relationships to global diplomacy. Traditionally, negotiation research and practice have focused on strategies, techniques, and achieving outcomes that benefit the immediate goals of the parties involved. Often defined by measurable successes, this approach is rooted in transactional and analytical perspectives prioritizing short-term gains or compromises. However, such strategies frequently overlook the broader implications of negotiation outcomes, particularly their sustainability, ethical alignment, and long-term impact on elationships and society. In response to these limitations, there is an emerging call within the literature to integrate the principles of wisdom into negotiation processes. Wisdom, with its emphasis on ethics, balance, and foresight, introduces a transformative dimension to negotiation, aiming not only to resolve conflicts but also to address the common good and promote enduring solutions that serve all stakeholders. This broader, holistic approach is encapsulated in the concept of "wise negotiation." Wise negotiation seeks to transcend the immediate transactional goals of traditional negotiation by integrating deeper considerations of morality, empathy, adaptability, and sustainability. It involves not only the negotiation outcome but also the attributes of the negotiator and the dynamics of the negotiation process. This approach recognizes that successful outcomes in the short term may fail to resolve underlying issues, leading to conflicts that resurface over time. Wise negotiation, on the other hand, focuses on achieving equitable, ethical, and durable agreements, benefiting not only the negotiating parties but also the broader societal context. Despite its theoretical appeal, a significant gap exists in understanding the practical application of wise negotiation and its distinguishing characteristics from traditional negotiation. The present research aims to address this gap by systematically exploring the concept, its feasibility, and the variables that influence its success. The study’s objectives include differentiating between successful and wise negotiation, investigating whether wisdom can be effectively integrated into negotiation practices, and identifying the key variables influencing wisdom and negotiation. Variables such as emotional intelligence, perspective-taking, morality, and adaptability play a pivotal role in shaping negotiation outcomes and are central to understanding the characteristics of wise negotiators. Moreover, this research seeks to develop and validate a framework for incorporating wisdom into negotiation processes, providing a practical guide for achieving sustainable and ethical agreements. The study employs implicit and explicit methods to achieve these objectives, ensuring a robust empirical foundation. The research comprises four studies designed to examine the existence and applicability of wise negotiation while identifying the factors influencing it. Study 1 explores whether wise negotiation is feasible in practice through a pre-and post-test design with a wisdom training program conducted between assessments (n = 100). The results revealed that raising awareness of wisdom-related variables significantly increased participants' application of these principles in negotiation, demonstrating the practicality of wise negotiation. These findings underscore the idea that while wisdom may be an abstract construct, its principles can be taught, understood, and applied effectively in real-world scenarios. This is a critical argument in favor of incorporating wisdom into negotiation practices, as it challenges the notion that wisdom is solely an innate quality and highlights its potential as a skill that can be cultivated. Study 2 builds on these findings by examining expert perspectives on wise negotiation. Interviews with renowned researchers specializing in negotiation, organizational behavior, and wisdom (n = 25) were analyzed using grounded theory methods. The analysis identified five clusters that define wise negotiation: emotional empathy, smooth processes, collaboration, ethical outcomes, and justice. These clusters contrast with those associated with successful negotiation, such as challenges, immediate outcomes, and implementation-focused collaboration. Experts emphasized that wise negotiation involves a heightened awareness of emotions, ethical decision-making, and a commitment to the common good—elements often absent in traditional definitions of successful negotiation. This differentiation provides a compelling argument for rethinking how negotiation success is defined, moving beyond immediate wins to include long-term sustainability and ethical integrity. Study 3 expands the scope by involving organizational participants actively engaged in workplace negotiations (n = 313). Using grounded theory analysis, this study identified that wise negotiators are characterized by flexibility, morality, long-term societal contributions, and the ability to integrate the needs of both parties. In contrast, successful negotiators often prioritize immediate gains and personal satisfaction, sometimes at the expense of broader societal interests. The analysis yielded eight clusters distinguishing wise negotiation from successful negotiation, with two clusters—emotional engagement and prioritizing the common good—unique to wise negotiation. These findings further support the argument that wise negotiation offers a more comprehensive framework for conflict resolution that addresses traditional negotiation practices' limitations. Study 4 delves into the behavior of wise negotiators, focusing on how opponent characteristics and situational factors influence negotiation outcomes. Unlike traditional studies, which manipulate negotiator behavior to assess outcomes, this study examined wise negotiators nominated by their organizations (n = 51). Using a 4X3X2 factorial design, the study manipulated opponent archetypes, reciprocity styles, and situational emotionality to assess how wise negotiators adapt their strategies. The findings revealed that situational and opponent characteristics significantly influenced negotiation outcomes, but these effects diminished when wisdom components were statistically controlled. This result underscores the central role of wisdom in shaping negotiation strategies, as wise negotiators consistently rely on their wisdom attributes to navigate complex situations. Additionally, a secondary 2X2 design examined the role of gender, revealing differences in how male and female opponents were treated. However, the gender of the wise negotiators did not influence these differences. These findings highlight the nuanced interplay between situational, opponent, and personal characteristics in wise negotiation, further supporting its practical applicability. Thus, across all four studies, the research effectively addresses the proposed questions, providing valuable insights into the concept of wise negotiation. By exploring its defining characteristics, including the pivotal role of emotion, the studies advance a nuanced understanding of how negotiation can evolve into a practice that balances relational, ethical, and outcome-focused considerations, fostering a more equitable and empathetic approach to conflict resolution. By integrating triangulation throughout the research design, this study effectively mitigated the biases and limitations inherent in relying on a single method or population. The convergence of insights from diverse participant groups and methodological approaches strengthened the validity of the proposed framework for wise negotiation. This rigorous approach highlights the framework's potential to inform practice and theory, offering a reliable model for fostering wisdom in negotiation across varied contexts. The study addresses both theoretical and practical dimensions and thus provides a holistic approach to negotiation that moves beyond the narrow focus on short-term success. It lays a foundation for achieving equitable, sustainable, and impactful solutions, offering valuable insights for scholars, practitioners, and policymakers alike. This multifaceted framework thus represents a significant step forward in bridging the gap between wisdom and negotiation literature.Publication Development Of Process Monitoring Solutions For Integrating Legacy Machine Tools to Industry 4.0 Framework(Indian Institute of Technology, Jodhpur, 2025-01-15) Desai, Kaushal A.Industry 4.0 envisages the implementation of sensors, Internet of Things (IoT)-based automation, and communication elements on shop floors to connect machine tools with networked systems and achieve "smart" functionalities. For example, product quality and productivity improvements can be accomplished effectively through real-time data acquisition and monitoring of manufacturing processes. The existing installation of legacy machines is a significant obstacle in realizing the potential benefits of smartness, as it offers no or limited adaptability to these changes. The implementation is further complicated in Small and Medium-sized Enterprises (SMEs) due to diverse manufacturing capabilities, restricted financial resources, and a scarcity of skilled human resources. Therefore, it is imperative to develop scalable and cost-effective solutions that enable SMEs to achieve process monitoring functions without significant investments. The doctoral thesis addresses these challenges by developing a digital assistant and platform-based manufacturing process monitoring architecture to integrate the legacy machine tools in the Industry 4.0 paradigm. The effectiveness of process monitoring solutions developed using these elements is corroborated by conducting a pilot study on the legacy engine lathe, drilling, and milling machines. The digital assistant acts as a decision support system to improve perceptions of legacy machine tool operators with broader skill sets in identifying process faults and monitoring component dimensions. Traditionally, machine operators monitor the process by frequently stopping the operation to verify specific characteristics, reducing productivity. The digital assistant captures the expertise of skilled operators to provide continuous monitoring and guidance during the operation. It utilizes a sensor-based system, feature extraction techniques, and a novel approach motivated by learning through demonstration for digitizing the expertise. The pilot study developed a digital assistant for component dimensions, tool wear state, and chatter onset monitoring for sample machine tools. The results demonstrated the effectiveness of a digital assistant in identifying in-process component dimensions, capturing tool wear states, and detecting chatter onset. A platform-based system, Manufacturing Process Monitoring as a Service (MPMaaS), was conceptualized to address challenges with the inaccessibility of human resources, which have technical expertise in developing and implementing process monitoring solutions. The architecture contains three layers: the user layer, the expert layer, and the hardware and software layer. It enables efficient interactions for requirement assessment and development of process monitoring solutions using technical experts of varied skill sets without ownership of hardware, software, and human resources. The pilot study on implementing MPMaaS was conducted to demonstrate experts' responsibilities and user-expert interactions while realizing a process monitoring solution. Industry 4.0 enables access to value-added services by integrating process monitoring outcomes with the enterprise network. However, a unified protocol is required to enable machine-machine, human-machine, and machine-system communications. Digital Manufacturing Infrastructure (DMI) is proposed in the thesis to integrate the digital assistant and MPMaaS at the machine, enterprise, and service-provider levels. The unified information model is developed using the Open Platform Communications Unified Architecture (OPC-UA) protocol at the machine level to transmit the data at the enterprise level for additional services such as operator performance monitoring, machine utilization, process control, and quality management through a centralized dashboard. The service provider level enables data and resource sharing for business functions at the enterprise level. A pilot study demonstrates the integration of legacy machines as connected entities in realizing digital SMEs. The thesis outcomes present various monitoring solutions facilitating the integration of vast legacy machines into the Industry 4.0 paradigm.Publication Experimental investigation on pipeline steel welds fabricated using formulated SMAW electrode coatings(Indian Institute of Technology, Jodhpur, 2025-01-02) Chhibber, RahulThe growing energy demand and advancements in pipeline steel technology necessitate the development of specialized welding consumables. This study examines X70 pipeline steel welds using formulated SMAW electrode coatings, with a focus on consumable performance, weld undermatching, hydrogen effects, and ductile fracture modeling. The flux formulation was targeted for high basicity, lower silica and rutile, substitution of CaO with BaO, low hydrogen (high CaF2). Four major constituents were selected for investigation, CaF2−CaO−Al2O3−BaO and CaO−SiO2−CaF2−BaO. Extreme vertices design approach was used for experimental design. The flux was investigated for contact angle, work of adhesion, and floatation coefficient, weight loss %, enthalpy change, thermal diffusivity, thermal conductivity, specific heat. Neural network models were developed for enhanced prediction accuracy. Increasing CaO and BaO raises the work of adhesion and lowers the flotation coefficient, while increasing Al2O3 and CaF2 decreases the work of adhesion and raises the flotation coefficient. The structural analysis of as-quenched slag was done by XRD, UV-vis, and FTIR. The CaO and BaO act as network breakers and release non-bridging oxygen O− at the expense of bridging oxygen O0. The contact angle decreases with the increase of CaO and BaO. The increase in individual constituents Al2O3 and CaF2 increases the contact angle. The Al2O3 act as a network former in the melts. The CaF2 present in the melt as Ca2+ and F− due to higher CaF2 concentration (~35%) which has positively affected the contact angle. An increase in CaF2 exhibits better thermal stability compared to the other minerals used. An increase in CaO and BaO has positive an influence, comparatively, BaO has more thermal stability. The primary cause of weight loss is due to moisture, crystallization water, calcination, and other volatile compounds present in the mineral. The thermal stability of flux while heating results in lower gaseous infiltration in the molten weld pool. Increasing alumina enhances thermal diffusivity, while an increase in calcite lowers thermal diffusivity. The solubility of water vapor in molten slag was estimated to range from 3.095 to 3.546. A series of multi-pass bead-on-plate studies were conducted using laboratory-developed electrodes. The flux composition has shown a significant effect on all the responses. An increase in Al2O3, and BaO has shown a positive influence on nickel transfer, whereas an increase in CaO reduces nickel transfer. The slag detachability was found to be good for the ratio CaF2:CaO:Al2O3:: 1.76:0.73:0.51. Selection of better-performing electrode coatings was done. Two weldments were prepared using developed welding electrodes (AF_W, SF_W), and one using a commercial electrode E8018-G (CE_W) for comparison purposes. The mechanical, metallurgical, and hydrogen charging tests were performed. Even with the same electrode rod (ER80S-Ni1), both coating compositions have shown significant effects on the weld. The AF_W and SF_W welds have shown thin grain boundaries and acicular ferrite as compared to CE_W. The results were confirmed by a thermodynamic model that shows a reduction in ferrite and pearlite. Microhardness results are in agreement with phase fraction microhardness results. Due to fine ferrite morphologies, lower hydrogen embrittlement index for AF_W was achieved. Weld strength mismatch in decreasing order is SF_W, AF_W, and CE_W. The σ𝑌𝑆/σ𝑈𝑇𝑆 ratio of weld AF_W was better than the other welds. Uniaxial tensile tests and single edge notch bend tests with ao/W=0.50 and ao/W=0.25 in-plane constraints were tested for X70 steel and weld (AF_W). The single edge notch bend pre-crack was prepared using electric-discharge machining. The test results of ao/W=0.50 were used to calibrate the GTN parameters using the design of experiment. The GTN model parameters were validated on ao/W=0.25 and flat notch tensile test experiments. The GTN model parameters were also validated on notch round bar and single edge notch tension test. The weld inhomogeneity was considered to simulate the pop-in behavior of single-edge notch bend tests. The simulations of single-edge notch bend tests with EDM-cut cracks and sharp cracks were studied, showing that the initial fracture toughness increases for EDM-cut cracks.Publication Kinetics of Phase Transitions in Multicomponent Fluid Mixtures Using Computer Simulations: Role of Surface Potential and Mixture Composition(Indian Institute of Technology, Jodhpur, 2025-06-17) Jaiswal, Parbhat K.Phase transitions are transient processes in which a thermodynamically unstable or metastable state evolves to a stable state driven by minimizing the appropriate free energy. The instability or metastability occurs due to sudden changes in external parameters such as temperature, pressure, etc. Subsequently, the system undergoing phase transition finds itself in a far-from-equilibrium unstable state characterized by complex spatiotemporal pattern formation, where the patterns account for domains enriched in the preferred states. The phase transition dynamics are subject to the nonuniformities present in the form of defects, such as domain interfaces costing free energy, and the system proceeds by annealing these defects. Such an annealing process adopts nonequilibrium dynamics in the growth and coarsening of the domains, commonly referred to as domain growth, coarsening kinetics, and phase-ordering kinetics. The objectives of my thesis comprise systems that exhibit domain growth and coarsening kinetics in phaseseparating binary mixtures (AB). In our studies, the quenched mixture is unstable to infinitesimal long-wavelength fluctuations and spontaneously decomposes into A-rich and B-rich domains demarcated by interfaces. This process is a widely used paradigm for the coarsening kinetics and is known as spinodal decomposition (SD). Phase separation is recurring in most far-from-equilibrium systems. One of the primary focuses of my work is to analyze the commonalities and distinctions in these systems. The problems we address in our thesis emerge when we add surfaces to the phaseseparating mixtures. The phase-separating mixture in contact with a surface is commonplace in metallurgy, chemical, and biological systems. For immiscible mixtures, if the surfaces preferentially attract one of the species, the surface becomes the origin of composition waves, known as surface-directed spinodal decomposition (SDSD) waves. These SDSD waves are composed of alternating segments of the wetting (rich in the preferred component) and depletion layers (lacking preferred particles). Using numerical simulations, we specifically study the wetting kinetics in the systems undergoing SDSD with functional surface properties. Our focus remains on elucidating the roles played by composition ratio (A : B), hydrodynamics in the system, and the chemical and physical heterogeneity of the surface in contact. To begin with, we add a flat wall represented by an integrated wall potential V (z) with an attractive part ⇠ z−n, where z and n denote its depth below the horizontal fluid layer and its interaction range, respectively. We find that for critical compositions (A : B = 50 : 50), the wetting-layer thickness R1(t) at very early times exhibits a potentialdependent growth regime of R1(t) ⇠ t↵ with ↵ = 1/(n + 2) being the growth exponent. The potential-dependent growth next crosses over to a universal fast-mode regime with ↵ = 3/2. In contrast, much slower logarithmic behavior in R1(t) is seen initially for a short-ranged surface potential (n ! 1). Remarkably, a similar rapid growth with ↵ = 3/2 is seen in this case too. We invoked Siggia’s arguments to explain the fast-mode kinetics, where novel long-range correlations develop in the early phase separation stage, resulting in coating mechanism. Secondly, we investigate the role of the composition ratio in the binary mixture for a similar attractive long-range potential V (z). We show that R1(t) in early times slows down if the minority component (minority wetting) wets the surface. However, the potential-dependent growth of R1(t) ⇠ t1/(n+2) is obtained when the majority component (majority wetting) wets the surface. The contrasting results corroborate a local barrier of thickness greater than the thermal correlation length above the wetting layer for minority wetting. In this case, the probability of particles crossing the barrier to feed the wetting layer is lower. We also report the recovery of the potentialdependent growth for the minority wetting by weakening the local barrier. Furthermore, we replace the flat walls with amorphous ones to investigate the latetime growth regimes of R1(t). By choosing the amorphous walls, we could avoid surfaceinduced crystallization in the mixture and examine the wetting kinetics in SDSD for times much later than previously reported by molecular simulation. Using morphological characterization, we identify relevant length scales of phase ordering in the direction parallel [L||] and perpendicular [L?] to the wetting wall. Our results on the length scales show widely accepted growth exponents of ↵ = 1/3 (Lifshitz-Slyzov (LS) law) and 1 (Siggia’s mechanism), which are also universal. However, we could not observe the fast-mode as the coating mechanism was absent due to the roughness of the amorphous wall. Furthermore, we highlight the possible orientational e↵ects of the multilayeredstructures on domain coarsening near the surface. In the end, we replaced chemically homogeneous surfaces with chemically patterned substrates. By setting the pattern’s periodicity commensurate with the mixture’s inherent length scale, we notice the transposition of surface patterns to the fluid mixture in contact. The emerging patterns are denoted as a transient surface-registry regime exhibiting a dynamical crossover from surface-driven to other universal coarsening regimes. Moreover, we provide details of the scaling behavior for the registry formation and melting times as a function of the pattern size Mx. We further assess lateral domain morphologies and examine the crossover using correlation functions, structure factors, and domain length scales. The kinetics of SDSD are of great technological and scientific importance, o↵ering a pathway to curate and design functional materials by enabling precise control over their domain morphologies. Given the above, acquiring a detailed understanding of the process is beneficial.Publication Flexible Resistive Memory Devices With Solution Processed Polymer:2D Material Composites as Switching Layer(Indian Institute of Technology, Jodhpur, 2025-01-08) Tiwari, Shree PrakashFlexible electronics has emerged as an important technology due to its versatility and potential applications in various on-body wearables, electronic skin, smart prosthetics, and various devices for health monitoring. In recent years, resistive random-access memory (RRAM) has been extensively explored as a suitable non-volatile memory device for flexible electronics owing to its simple structure, ease of fabrication, and the ability to incorporate various engineered and solution processed switching layers which are suitable for low cost, low temperature and large area processing. Though there have been continuous efforts to enhance the performance of the solution processed flexible RRAMs, there have been multiple issues such as poor endurance and cycle to cycle variability which need to be addressed. This work is an effort towards applying strategies to address the performance issues of solution processed flexible RRAM devices. More specifically, it involves comprehensive exploration of composites of solution processed polymers and 2D materials aiming to improve the performance parameters as well as shelf-life stability. Moreover, multilevel resistive switching in flexible RRAM devices is also demonstrated. To start with, resistive switching behavior of bilayer of poly(4-vinylphenol) (PVP): molybdenum disulfide (MoS2) composite and TiO2 in RRAM devices were explored on both rigid and flexible substrates. Flexible devices fabricated with this PVP:MoS2/TiO2 bilayer on polyethylene naphthalate (PEN) substrate operated on low average SET and RESET voltages (VSET & VRESET) of 1.5 V and −0.7 V with decent endurance of 200 cycles and high ION/IOFF of more than 103 at reading voltage of 0.2 V. These devices maintained decent switching upon bending up to a radius of 7 mm. The next engineered combination was poly(N-vinylcarbazole) (PVK):MoS2/TiO2. Flexible RRAM devices with this hybrid bilayer exhibited excellent switching with low VSET and VRESET of 1.2 and -1.5 V respectively, high endurance of 1000 cycles, and high stability upon bending with radii up to 7 mm for 100 cycles. A comprehensive investigation of long-term environmental stability and performance was also performed by systematically characterizing the devices for a duration of 20 months and it was found that devices were able to maintain their switching behavior with excellent retention of 104 s even after being in ambient environment for this long duration, indicating high shelf life. Moreover, effect of exposure to humidity and heating were studied confirming good stability against these. These investigations indicated suitability of PVK:MoS2/TiO2 as a switching layer candidate for environmentally stable RRAM devices for flexible electronics. Finally, composite of a rarely explored 2D material (MoSe2) with PVP (PVP:MoSe2) was demonstrated as a potential resistive switching layer for flexible RRAM devices. Fabricated flexible RRAM devices exhibited forming-free and excellent resistive switching with low VSET & VRESET (0.7 V / ~ -1 V), high DC endurance of more than 1000 cycles, and excellent retention time of 104 s with decent ION/IOFF of ~103. These devices exhibit multilevel resistive switching for 2-bit storage (four levels), by tuning the compliance current values, which can be the simplest way to achieve this functionality. This study also opens up a direction for exploration of other unique material combinations for switching layers towards application in multibit storage, as it may contribute to low cost, high density, and nonvolatile flexible RRAM devices.Publication Management of Mitochondrial Oxidative Stress and Neurogenesis Using Bioengineered Nanomedicine Platform(Indian Institute of Technology, Jodhpur, 2024-12-19) Ghosh, SurajitThis thesis entitled “Management of Mitochondrial Oxidative Stress and Neurogenesis using Bioengineered Nanomedicine Platform” talks about the development of various therapeutics for the treatment of oxidative stress in the central nervous system (CNS) and peripheral nervous system (PNS). The complex pathophysiology of traumatic brain injury (TBI) is a major obstacle, as it includes the central nervous system's (CNS) limited regenerative capacity and an overabundance of reactive oxygen species (ROS). Another challenge is the blood-brain barrier (BBB), which limits the ability to distribute therapeutic medicines to areas that are inflammatory. To address these difficulties, we developed a new approach to treatment using polydopamine (PDA)-coated mesoporous silicon nanoparticles (PDA-AMSNs) to transport a neurochemical modulator (NCM), a possible inhibitor of glycogen synthase kinase-3β (GSK- 3β). A multifunctional therapeutic matrix was created by integrating these nanoparticles with a PANAP hydrogel, which is known for its neuroprotective properties. We created a logic AND gate circuit with PDA-AMSNs and NCM as inputs and neuroprotection as output by injecting this composite system, PDA-AMSN-D, into a cryogenic brain injury (CBI) model. The results highlighted the system's potential for TBI management by demonstrating significant therapeutic efficacy, which included a reduction in infarct volume, enhancement of neurogenesis, restoration of BBB integrity, and improved neurological recovery. This thesis also talks about the design and development of novel mitochondria targeting gallic acid-derived small-molecule drugs for the alleviation of oxidative stress in LPS-induced neuroinflammation. The Overproduction of reactive oxygen species (ROS) by mitochondria, which are essential for cellular homeostasis and energetics, can cause oxidative stress. Neuroinflammation and neurodegeneration are significantly associated with mitochondrial dysfunction. In response to these concerns, we created Mito-TBA, an antioxidant that targets mitochondria and is based on gallic acid and the mitochondriotropic triphenylphosphonium (TPP) cation. Significant anti-inflammatory and antioxidative effects were shown by this new chemical, Mito-TBA-3. In vitro studies demonstrated that Mito-TBA-3 protects neurones derived from PC-12 by inhibiting mitoautophagy, attenuating the activation of lipopolysaccharide-induced toll-like receptor 4 (TLR-4), and activating the Nrf-2/ARE pathway. In a rat model of neuroinflammation caused by LPS, Mito-TBA-3 restored memory loss, reduced depressive symptoms, prevented further inflammation, and lowered levels of proinflammatory cytokines. One possible treatment possibility for neurodegenerative illnesses related to mitochondrial oxidative stress is this chemical, which outperformed aspirin, a commonly used NSAID. Debilitating neuropathies and functional deficits can result from peripheral nerve injuries, especially those that impact the sciatic nerve. Further, this thesis talks about the development of novel peptide-derived scaffolds for nerve regeneration on PNS. For nerve restoration to be successful, it is necessary to precisely align the fascicles so that the nerve sprouts and Büngner bands can reattach. Although autogenous nerve grafting is still highly recommended, it does have certain drawbacks, such as donor site morbidity and inadequate repair efficacy. There is a lack of therapeutic potential in current tissue-engineered nerve scaffolds due to their absence of electrical conductivity, fibre alignment, and components of the extracellular matrix (ECM). A nanofibrous ECMmimicking self-assembling peptide hydrogel, including neuroregenerative motifs (NAP and NAV) and a self-assembling motif (K2(SL)6K2) was devised to address these challenges. Important for directing stem cell orientation and encouraging neurite outgrowth, this hydrogel displayed topographical patterns on a nanoscale. Using morphological and histological investigations, functional assessments, and gastrocnemius muscle reinnervation, the hydrogel enabled structural healing and functional recovery within two weeks in a rat model of sciatic nerve injury. These results demonstrate that hydrogel may be a viable therapeutic option for repairing peripheral nerves. Overall, this thesis gives a glimpse where combining these three treatment modalities highlights the need for new ways to deal with central nervous system trauma, neuroinflammation, and peripheral nerve injury. Each approach takes advantage of ideas from bioinspired design to provide specific, efficient therapies for nerve and neurological disorders. They open the door to a new age of precision medicine and give patients with diseases that were thought to be incurable a glimmer of hope.Publication Exploring the Potential of Cell and Tissue Derived Extracellular Vesicle for the Development of Novel Neuro Therapeutics for Adult Neurogenesis(Indian Institute of Technology, Jodhpur, 2024-12-12) Ghosh, SurajitAging and neurodegenerative diseases significantly impair adult neurogenesis, leading to reduced neuroplasticity and neuronal regeneration. This decline in neurogenesis, specifically within the subventricular zone (SVZ) and the hippocampus, is characterized by a reduction in neural stem cell (NSC) proliferation and an increased number of quiescent NSCs. As aging progresses, neurogenic populations within the brain become increasingly depleted, contributing to cognitive decline and neurodegenerative diseases such as Alzheimers and Parkinson’s disease. While current therapies such as stem cell transplantation and neurodegeneration prevention strategies offer potential, they have limited success in reversing age-related damage or promoting effective regeneration. Therefore, novel approaches that target the enhancement of NSC proliferation and differentiation are needed to combat these challenges. Extracellular vesicles (EVs), nanosized lipid bilayer vesicles secreted by cells, have emerged as a promising platform for therapeutic delivery due to their ability to traverse the blood-brain barrier and their non-invasive, non-immunogenic, and nontumorigenic properties. In particular, exosomes derived from stem cells and other tissue sources have been identified as potential mediators of cellular communication and regeneration, capable of promoting differentiation, proliferation, and survival of NSCs. In this study, we investigate the therapeutic potential of adipose tissue stem cell-derived EVs (Exo- Pep-11) engineered with a peptide targeting EphA4 receptors on NSCs. EphA4, a receptor specifically expressed by neural stem cells, is a member of the Eph receptor tyrosine kinase family, known for its involvement in developmental processes such as cell migration and differentiation. By designing a peptide-based ligand targeting the EphA4-Ephrin-B2 interaction, we conjugated this peptide with EVs, creating Exo-Pep-11, which is capable of specifically targeting NSCs through EphA4 receptors. Our results demonstrate that Exo-Pep- 11 efficiently internalizes into NSCs in both in vitro and in vivo models, enhancing their proliferation and differentiation, with significant potential for neurogenesis. In vitro assays show that Exo-Pep-11 significantly enhances the proliferation of NSCs, with a ~1.9-fold increase in cell proliferation and a ~2.4-fold increase in the expression of the ID1 protein, a key regulator of NSC proliferation. Moreover, we observe a ~1.4-fold increase in Nestin expression, a marker of undifferentiated NSCs. Importantly, the receptor-specific uptake of Exo-Pep-11 by NSCs is confirmed through pre-treatment with an EphA4-specific antibody, which reduces the uptake by approximately 2.3-fold, suggesting that the ligand-receptor interaction is crucial for the targeted delivery of the engineered EVs. These findings highlight the effectiveness of Exo-Pep-11 in enhancing NSC rejuvenation, an essential step in mitigating age-related decline in neurogenesis. Further, we explore the potential of Exo-Pep-11 in promoting neurogenesis in aging rats, specifically in the olfactory bulb (OB), a region known for continuous neurogenesis throughout life. In aging rats, neurogenesis is impaired, and the ability of NSCs to differentiate into functional neurons is reduced. However, treatment with Exo-Pep-11 leads to significant improvements in neurogenesis, with a ~1.6-fold and ~1.5-fold increase in the expression of tyrosine hydroxylase (TH) and Tuj1, respectively, in the aging rat OB. These results suggest that Exo-Pep-11 not only targets NSCs but also enhances their differentiation into dopaminergic neuronal subtypes, which is particularly relevant in the context of age-related neurodegenerative diseases such as Parkinson’s disease. In parallel, we investigate the neurogenic potential of EVs derived from the substantia nigra (SN) of rat brains. The SN is a key brain region involved in dopaminergic neurotransmission and is particularly susceptible to neurodegeneration in Parkinson’s disease. Using an aging rat model treated with 6-hydroxydopamine (6-OHDA) to induce dopaminergic neurodegeneration, we assess the role of SN-derived EVs in promoting dopaminergic neurogenesis and mitigating neurodegeneration. Our results reveal that EVs from 1-monthold rats (SN-EV-1) show the most potent effects in inducing NSCs to differentiate into dopaminergic neurons. In vivo, SN-EV-1 treatment increases the expression of dopaminergic markers, such as TH and dopamine transporter (DAT), and enhances NSC migration to the OB, providing strong evidence of the regenerative potential of SN-derived EVs in the context of neurodegeneration. We also demonstrate that SN-EV-1 treatment improves behavioural outcomes in the aging rat model, highlighting the neuroprotective and neurogenic properties of these vesicles. The therapeutic effects of SN-EV-1 are further supported by histological analysis, which reveals enhanced NSC differentiation and migration to the OB, underscoring the ability of SN-derived EVs to rejuvenate neurogenic niches in the aging brain. These findings establish a foundation for exploring SN-derived EVs as a potential therapy for neurodegenerative diseases like Parkinson’s disease, where dopaminergic neurodegeneration is a hallmark feature. In the continuation of our previous work, we have developed an efficient protocol for isolating SN-EVs and conducting subsequent proteomic studies. This research enhances our understanding of the potential of EVs, particularly those engineered to target NSCs, in rejuvenating aging neural populations and promoting neurogenesis. Additionally, it contributes to our understanding of disease mechanisms and biomarker discovery. With further optimization and clinical testing, these EV-based therapies and studies on EV mechanisms could provide a novel and effective strategy for addressing age-related cognitive decline and neurodegenerative diseases, offering new hope for patients suffering from conditions such as Parkinson’s disease, Alzheimer’s disease, and other neurodegenerative disorders.Publication Smart-Engineered Small Molecule -Based Potential Therapeutic Development for Duchenne Muscular Dystrophy(Indian Institute of Technology, Jodhpur, 2024-12-21) Ghosh, SurajitDuchenne muscular dystrophy (DMD) is a debilitating genetic disorder characterized by progressive muscle degeneration and weakness, predominantly affecting males at a rate of approximately 1 in 3500 births. It arises from mutations in the dystrophin gene on the X chromosome, resulting in deficient or absent dystrophin protein. Current therapeutic strategies focus on specific mutations using exon skipping and stop codon read-through to restore dystrophin function, though limited to certain patient populations. Gene therapy approaches, employing viral vectors and gene editing like CRISPR/Cas9, aim to deliver functional dystrophin genes to muscle cells, yet clinical implementation remains under investigation. However, in the majority of cases, the current therapeutic paradigm for managing DMD primarily emphasizes on symptomatic treatment. Although these symptomatic and supportive treatments have shown limited success in improving the life expectancy of individuals with DMD, but there is no currently available treatment that can modify the course of the disease and treat the universal DMD population. Our research addresses these challenges with a multifaceted approach. Here, our overall goal is to design, develop and further validate small molecule and peptide based therapeutics targeting different key strategies to combat DMD and providing better life care support for global DMD population. This study presents a multi-faceted therapeutic approach addressing key challenges in DMD management, including utrophin modulation, antisense oligonucleotide (ASO) delivery, and the mitigation of secondary pathological hallmarks. Firstly, we designed and synthesized a library of seventy novel quinazoline- and quinoline-based small molecules as utrophin modulators. High-throughput In-cell ELISA screening identified SG-02 as the most promising candidate, exhibiting 2.7-fold upregulation of utrophin at a nanomolar concentration doses of 800 nM in a dose-dependent manner. Mechanistic studies performed identified SG-02 as a potent antagonist of the aryl hydrocarbon receptor (AhR). SG-02 exhibited high binding affinity to AhR, with a dissociation constant (Kd) of 41.68 nM, indicating strong target engagement. Furthermore, SG-02 enhanced myogenesis by upregulating myosin heavy chain (MyHC) expression, a key marker of muscle differentiation. These results highlight SG-02 as a promising therapeutic agent for DMD that targets utrophin upregulation through AhR antagonism, offering broad applicability to the DMD patient population. Second, to address the delivery limitations of antisense oligonucleotides (ASOs) for exon-skipping therapies, we developed a novel short non-cationic cell-penetrating peptide (CPP), ETWWK. This peptide was specifically designed by avoiding richness of positive charged amino acids to enable efficient conjugation with the negatively charged 2'-O-methyl phosphorothioate (2OMePS) ASO backbone using click chemistry. Functional studies demonstrated that the ETWWK-ASO conjugate successfully delivered ASO to the nuclear compartment, its intended site of action, achieving a 2-fold upregulation of dystrophin mRNA expression compared to untagged ASO. These findings mark a significant advancement in ASO delivery systems, addressing prior limitations such as low nuclear access, poor selectivity, and compromised cytotoxicity. Lastly, we focused on mitigating secondary pathological hallmarks of DMD progression by developing a novel therapeutic peptide, E.M.P-2. Designed with mitochondrial targeting and calcium-chelating properties, E.M.P-2 promoted myogenesis by upregulating key myogenic markers, myosin heavy chain (MyHC) and myogenic differentiation factor (MyoD), by more than 2-fold at a concentration of 150 nM. In addition, E.M.P-2 effectively mitigated fibrosis by downregulating collagen type I alpha 1 chain (COL1A1), a critical fibrosis marker, by 60%. The peptide also restored impaired calcium homeostasis within mitochondria and the cellular environment, a key factor in muscle regeneration. Furthermore, E.M.P-2 exhibited anti-inflammatory properties by significantly reducing IL-6 expression in DMD patient-derived cells, which display elevated baseline IL-6 levels. Overall, E.M.P-2 represents a first-in-class peptide therapeutic capable of addressing multiple pathological features of DMD, including fibrosis, impaired myogenesis, calcium dysregulation, and inflammation. This peptide holds the potential to replace corticosteroids, the current gold standard for DMD treatment, which are associated with significant long-term side effects. Together, these findings demonstrate a comprehensive therapeutic strategy for DMD, advancing the field through small-molecule utrophin modulators, innovative CPP-ASO conjugation systems, and peptide-based interventions targeting secondary disease hallmarks. My research endeavours provides a multifaceted therapeutic approach aimed at addressing the needs of the broader DMD population and providing cost-effective supportive care.Publication Xurography-Based Microfluidic Platform for Mimicking Neuronal cytoarchitecture and Exploring its Application in Neurodegenerative Disease Research(Indian Institute of Technology, Jodhpur, 2025-01-03) Ghosh, SurajitThe brain is an intricate system composed of millions of neural networks. Deciphering its overall dynamics and the underlying significance of several cues that direct neuronal development, the formation of axons, dendrites, and synapses during wiring and re-wiring remains a formidable challenge in developmental and cellular neuroscience. Although traditional in vitro macroscopic cell culture techniques are easy to perform, they often fail to mimic the complex phenomenon of brain microenvironments. Recent advancements in microfluidic device-based cell culture technologies have successfully overcome the limitations of conventional cell culture methods, enabling the reconstitution of neural cytoarchitecture through precise spatiotemporal regulation of compartmentalized cell culture microenvironments. These lab-on-chip technologies can aid in elucidating the fundamental principles of brain function and provide innovative platforms for screening neurotherapeutics. This thesis offers a succinct overview of the structural and functional aspects of the human nervous system by the reconstitution of the central and peripheral nervous systems on the chip. It highlights the neurological disorders associated with dysfunctions in both systems. It also reviews the several strategies researchers have adopted to mimic neurogenesis on a chip. Additionally, we have designed and developed an economical, innovative microfluidic device utilizing a state-of-the-art Xurography technique. Thereafter, we performed on-chip cell culture studies with primary neurons and SH-SY5Y cells to validate the cytocompatibility of the device. Furthermore, we demonstrated the application of the fabricated device as a coculture model using astrocytes and neurons. The device also served as a drug screening platform for a multi-targeted compound in the differentiated SH-SY5Y cells in the context of Lastly, we also developed a Ferroptosis model that can be linked to neurodegenerative disorders. In this regard, we also investigated the efficacy of a synthesized small molecule inside our fabricated microfluidic device. All these lead to the conclusion that our simple and cost-effective Xurography-based microfluidic device can open gateways to decipher neuronal events inside the human brain and serve as potential platforms for neurodegenerative disease modelling and screening novel therapeutic agents.Publication Cold Sterilization Studies Using UV Irradiation and DBD Plasma to Supplement the Current Techniques for Milk Preservation(Indian Institute of Technology, Jodhpur, 2025-01-08) Prakash, RamMilk, one of the most complete nutrition mixes for human consumption, also presents itself as the most potent nutrient medium for bacterial growth. This becomes especially pronounced for a hot country like India with highly fragmented milk production, spoiling the milk before it reaches processing plants. In recent years, the search for less expensive alternatives to cold chain preservation and heat-based shelf-life improvement has intensified. Hence, the study of the impact of Ultraviolet (UV) radiation and plasma on the physicochemical properties of various substances, including milk, has gained prominence. UV-C (200–280 nm) is also wellknown for inactivating various bacteria and spores in the aqueous solution based on its DNA absorption capacity. However, the hazardous impact of conventional UV lamps on individuals and the environment due to the presence of mercury limits their usage for sterilization purposes. Far UV-C (222 nm) treatment has emerged as a potential method to replace conventional 254 nm low-pressure mercury UV-C lamps to ensure the microbiological safety of food items. In this thesis, research focuses on utilizing dielectric barrier discharge (DBD) plasma sources and DBD based mercury-free 222 nm and 253 nm exciplex sources to investigate the microbial and physicochemical properties of milk. In the first study, we demonstrate a DBD based mercury-free 222 nm exciplex source and compare it with 253 nm and pasteurization methods. The UV dose delivered to the milk samples has been estimated using the chemical actinometry method and found to be 10.9 J/ml. The methylene blue reduction test (MBRT) of milk has been increased more than 5 h, within just 2.5 min of far UV-C treatment. Approximately 2.6 log and 2.1 log decrease in the E. coli and S. aureus have been achieved after 2.5 minutes of 222 nm treatment of whole milk. We infer that 222 nm UV light is more efficacious vis-à-vis 253 nm and pasteurization in increasing milk quality without altering its physicochemical properties, indicating its potential use as a more efficient sterilizing source for enhancing milk safety, quality, and shelf life. In a further study, we have focused on designing a continuous milk treatment annular UV reactor. The MBRT of milk has again increased more than 5 hours, within just four passes through the UV reactor. Approximately 5 log reductions in the Salmonella typhimurium and S. aureus have been achieved in three passes of whole milk. We found that the proposed UV reactor has an identical performance in inactivating the microorganisms compared to pasteurization without altering its physicochemical properties.In another study, an effort has been made to design a DBD based large volume surface plasma discharge system for direct treatment of milk. The developed system is optimized for operational parameters, and raw milk has been treated at different time intervals. The pH and color characteristics of raw milk samples have not been affected by the proposed cold plasma treatment. Nevertheless, the conductivity of the milk significantly increases with presence of charged ions assisting reduction of harmful bacteria in the milk. After continuous operation of the system for more than 30 minutes, there was no significant change in the raw milk temperature, which is a key requirement for milk decontamination without milk heating up using a cold plasma treatment in the developed DBD geometry. This thesis presents a promising potential for the use of mercury-free far UV-C irradiation as a viable and non-thermal technology in the dairy industry, food sector, and overall sterilization applications. It highlights the capabilities of dielectric barrier discharge based cold plasmas to enhance milk safety, quality, and shelf-life, presenting a more efficient alternative for improving these aspects compared to traditional methods.Publication In Silico Studies of Stress tolerance genes in non-desert and desert plants(Indian Institute of Technology, Jodhpur, 2024-12-13) Yadav, Pankaj; Sadhukhan, AyanThe global population is expected to exceed 10 billion by 2050, posing a significant challenge to the agriculture sector in fulfilling increased demands of food production. This necessitates the adoption of sustainable strategies to ensure global food security. Among staple food crops, Oryza sativa (rice) is a cornerstone of global food production, serving as a dietary staple for nearly half of the world’s population. However, its productivity is severely constrained by biotic and abiotic stresses. Biotic stress includes pathogenic bacteria, fungi, and other organisms, while abiotic stresses such as drought, such as drought, and heat can result in yield losses of up to 90-100%. To mitigate these impacts, O. sativa possesses an intrinsic defense mechanism involving stress-responsive genes and proteins. Despite this, current interventions, including the use of pesticides and conventional breeding techniques, often provide only temporary relief. In response, the integration of computational tools with advanced breeding strategies has emerged as a promising avenue to enhance the resilience and productivity of O. sativa under stress conditions. This holistic approach has the potential to address the limitations of traditional methods and contribute to sustainable food production systems. This thesis addresses the challenges posed by biotic and abiotic stresses in O. sativa by focusing on the identification, characterization, and analysis of stress-tolerant genes and proteins through computational approaches. The study has three primary objectives. First, it aims to identify novel disease-resistance proteins in O. sativa Japonica through in silico methods, targeting bacterial leaf blight (BB) and rice blast (RB) diseases, which are major biotic stressors affecting productivity of O. sativa. Second, it seeks to predict disease-resistance proteins in O. sativa and its related species by evaluating and comparing the performance of various deep learning (DL) and machine learning (ML) algorithms, thereby identifying the most effective computational frameworks for accurate protein prediction. Lastly, the research involves drought-responsive transcriptomic and genome-wide studies of Prosopis cineraria, a drought-resilient leguminous tree from the Indian Thar Desert, to uncover drought-tolerance genes that could potentially enhance drought resilience in O. sativa. Together, these objectives aim to contribute to sustainable strategies for improving the stress resilience of O. sativa. In line with the objectives outlined above, five novel disease-resistance proteins were effective against BB and RB diseases in O. sativa were identified through a comprehensive in silico approach. These proteins were characterized using gene network construction, structural modeling, functional annotation, and phylogenetic analysis. The identified proteins exhibited key roles in disease-resistance mechanisms and showed evolutionary relationships with well-established resistance proteins. Furthermore, gene expression profiling revealed their differential expression under infections by Xanthomonas oryzae pv. oryzae (Xoo) and Magnaporthe oryzae, the causative agents of BB and RB diseases, respectively. These findings offer valuable insights for the development of disease-resistant varieties of O. sativa. To extend the scope of disease-resistance protein identification in O. sativa and related species, various ML and DL models were employed. These models were rigorously trained, tested, evaluated, crossvalidated, and compared for predictive performance. Among these, the DL-based Multi-Layer Perceptron model outperformed others, demonstrating precise prediction of disease-resistance proteins. The study thus provides computational frameworks and candidate proteins that can aid in breeding novel disease-resistant varieties of O. sativa. In addition, drought-tolerance genes from P. cineraria, a resilient tree species from the Indian Thar Desert, were explored to identify robust orthologs that could enhance drought resilience in O. sativa. Transcriptomic analyses under drought, highlighted the APETALA2/Ethylene Responsive Factor (AP2/ERF) superfamily as key genes induced under drought, compelling us to conduct a genome-wide analysis of this superfamily in P. cineraria. Comparative studies revealed significant copy number variations (CNVs) of AP2/ERF genes between drought-tolerant (DT) and drought-sensitive (DS) species, such as O. sativa Japonica, Arabidopsis thaliana, and Pisum sativum. Structural analyses of P. cineraria AP2/ERF proteins indicated stronger interactions between the DNA-binding AP2 domain of P. cineraria and the target cis element GCC box/dehydration-responsive element (DRE), as compared to orthologs from DS species. Additional investigations into amino acid variations and hydrogen bonding within AP2/ERF proteins among O. sativa Japonica, O. sativa Indica, and P. cineraria demonstrated substantial differences. Notably, DT P. cineraria AP2/ERFs contained polar amino acids at the variation positions and more hydrogen bonds compared to the orthologs from DS species O. sativa and A. thaliana, suggesting stronger DNA binding by AP2/ERF orthologs of DT species. In conclusion, this thesis presents a comprehensive in silico investigation of stress-tolerant genes and proteins in O. sativa, providing breeders with novel genetic resources for developing stress-resilient varieties of O. sativa. Overall, these findings contribute to enhancing the productivity and resilience of O. sativa, thereby advancing global food security efforts.Publication Investigation of Optoelectronic and Photo-electrochemical properties of metal halide perovskites for photo-Battery Applications(Indian Institute of Technology, Jodhpur, 2025-01-09) Ahmad, SahabThe fast rise in carbon emissions from 9.4 million tons to 37 billion tons since the beginning of the industrial revolution highlights urgent requirement of sustainable energy sources as the world confronts climate change and endeavors to achieve sustainability. During daylight, the solar cells can offer constant power supply for low power residential to high power industrial usages, however the intermittent nature of solar radiation requires energy storage systems to store the solar energy into electrochemical energy for usage in nighttime or at later stage. This conventional combination of solar cell and battery reduces energy poverty, but is very bulky and expensive due to the use of complex and multiple electronic components, duplication of electrodes as well as require use of various materials for these two very different type of devices. In contrast, photo-batteries, also known as photo-rechargeable batteries (PRBs), offer a compact energy solution by integrating solar harvesting and energy storage functionalities in a single device. These PRBs are composed of either single or dual active materials which can perform solar energy harvesting like a PV device and concurrently stores it in the form of electrochemical energy like a battery. The overall performance of these PRBs highly depends upon the optoelectronic and electrochemical properties of the active materials. This thesis involves the investigation of advanced PRB systems by exploring the single active material systems based on metal halide perovskite (MHPs). Bulk (3D) MHPs of type AMX3 (formula defined below) are solution processed semiconductors and offer an ideal material system for low-cost PVs, however these materials suffer from stability issues due to degradation of their structural and optical properties under atmospheric and illumination conditions. Therefore, due to improved structural and optical properties of two-dimensional (2D) MHPs, compared to 3D MHPs, this thesis work highlights the investigation of optoelectronic, electrochemical and photo-electrochemical properties of 2D MHPs for PRB applications. Briefly, the Ruddlesden Popper (RP) phase 2D MHPs (R`)2(A)n-1MnX3n+1 (n=1-4) are studied by exploring their structural, optical, optoelectronic, electrochemical as well as photo-electrochemical properties. Here, R` is the monoammonium alkyl organic spacer cation, A is the smaller organic cation (MA=CH3NH3, FA=HC(NH2)2, Cs etc.), M is the divalent metal (Sn2+, Pb2+, Ge2+ etc.), X is the halide (Cl-, Br-, I-) and n denotes the number of inorganic layers between the organic spacer cations. In order to study these properties, a wide range of samples and devices are fabricated ranging from photodetectors, Li-Ion batteries (LIBs) to PRBs. These 2D MHPs are found to be an interesting candidate for PRB applications due to their flexible structural properties, improved stability in electrolyte medium, tunable optical properties, compatibility with carbon additives and binders, matching energy levels to the charge transport materials such as rGO, PCBM, MoS2, MXene etc. as compared to their bulk counterpart. A hybrid material using RP perovskite (BA)2(MA)n-1PbnI3n+1 (n=1-4) and a few layers of MoS2 nanoflakes is developed to investigate the optoelectronic and photo electrochemical properties. This hybrid material has shown improved transient photocurrent response than pristine material. Such improvement in the photocurrent leads to responsivity of ~ 97.7 μAW-1 and detectivity of ~ 6.93 x 108 jones at 0.0 V bias under 1 sun illumination, which are ~16 and ~10 times higher respectively as compared to pristine device. In continuation of prior work, this RP perovskite-MoS2 hybrid material based LIB exhibits an average discharge specific capacity of 129.17 mAhg-1 for 50 cycles at 294 mAg-1 current density. Whereas pristine RP perovskite LIB has shown a specific capacity of 25.60 mAhg-1 under similar conditions. Furthermore, the hybrid material-based Li-PRB has shown an average dark discharge specific capacity of 128.66 mAhg-1 at a current density of 64 mAg-1 which enhanced to 180.67 mAhg-1 (photo-enhancement: 40.42 %) under illumination. In addition, demonstrated hybrid Li-PRB has shown photo conversion and storage efficiency of 0.52 % under standard 1 Sun illumination, which outperforms other perovskite-based PRBs. An aromatic spacer cation-based RP perovskite of type (CH)2(MA)3Pb4Br13 and MXene nanoflakes based hybrid materials is fabricated and these RP perovskite-Mxene hybrid photodetector (n=4 + 1.5 mM MXene) has shown responsivity of ~1.51 x 102 AW-1 at 2.0 V bias under laser illumination (λex ~ 405 nm, Pin ~ 0.62 mWcm-2) which is ~8.39 times higher than pristine RP Perovskite photodetector. Furthermore, the effect of smaller organic cation (A = MA and FA) on the optoelectronic properties of aromatic spacer cation-based RP perovskite of type (CH)2(A)Pb2I7 is studied. Where perovskite with FA as a smaller cation has shown stable transient photocurrent response due to its high molecular weight which has resulted in responsivity of ~2.6 AW-1 and detectivity of ~3.6 × 1010 jones at 2.0 V bias under CW-laser illumination (λex ~ 405 nm, Pin ~ 5.87 mW/cm2). This thesis provides a novel approach to improve the optoelectronic, electrochemical as well as photo-electrochemical properties of 2D metal halide perovskites. ...