Designing of Transition Metal Oxide and Chalcogenide Nanostructures for Potential applications in Photoelectrochemical Devices

Supriya Ankush Patil 한양대학교 대학원 2016 국내박사

Abstract Designing of Transition Metal Oxide and Chalcogenide Nanostructures for Potential applications in Photoelectrochemical Devices Supriya Ankush Patil Dept. of Chemistry The Graduate School Hanyang University The growing need for energy by the human society and depletion of conventional energy sources demands a renewable, safe, infinite, low-cost and omnipresent energy source. One of the most suitable ways to solve the foreseeable world’s energy crisis is to use the power of the sun. Photovoltaic devices are especially based on metal oxides and chalcogenides of wide interest as they can convert solar energy to electricity. Among different types of nanomaterials, metal oxides and transition metal chalcogenide semiconductor nanostructures exhibit unique electronic, chemical and physical properties. The inherent properties of metal chalcogenide nanostructures can be further tuned depending upon their application to particular energy conversion device applications.The development of very simple, cost-effective and environment friendly methods, suitable for the large-scale synthesis of these, is therefore of great demand. Using metal oxdies (MOs) and transition metal chalcogenides (TMCs) nanostructurs, this thesis describe a methodology for improved power conversion efficiency of solar to electrical energy conversion devices. Chapter 1: This introduces the innovative, novel simple developed methodologies for metal oxides and metal chalcogenides nanostructure. Additionaly, a brief history of research plan on the clean energy demand and the goal of this research.Furthermore, discussion about historical background of photoelectrochemical cell and dye sensitized solar cell (DSCs), with structure and operating principle of DSCs for understanding the important aspects of energy conversion and storage. Chapter 2: We demonstrate an extremely simple but highly effective strategy for the synthesis of various functional metal oxides (MOs) such as ZnO, In2O3, Bi2O3, and SnO2 nanoparticles with various distinct shapes at room temperature via a solid-state reaction method. The method involves only mixing and stirring of the corresponding metal salt and base together in the solid phase, which yields highly crystalline metal oxides within 5-10 min of reaction time. The obtained paste can be directly doctor bladed onto a variety of substrates for photoelectrochemical applications. The proposed method does not require a sophisticated instrumental setup or harsh conditions, and the method is easily scalable. Hence, it can be applied for the cost-effective and large-scale production of MOs nanoparticles with high crystallinity. This method is easily scalable and can be employed for large scale production of crystalline metal oxide powders. As an example for potential applications of these metal oxides, we demonstrated the application of ZnO nanoplates as a photoanode in DSCs. Photoanodes composed of small nanoplates were spongy in nature, ensuring better connections among the nanostructures for the electron transport in the ZnO photoanode, and for the diffusion of redox couples in the electrolyte. We systematically studied the mechanism and the effect of the annealing temperature on DSCs. The device with the low-temperature treated ZnO photoanode obtained using the solid-state reaction has demonstrated a power conversion efficiency of 5%, which is certainly non-ignorable. Chapter 3: In the next part of the thesis, based on a coordination chemistry approach, the present work reports on the synthesis of thin films of various cobalt hydroxycarbonate nanostructures such as nanobeams, nanoneedles, and bending nanorods using three different cobalt precursors viz. Cl-, NO3- and CH3COO-. After pyrolysis in air, the hydroxycarbonate nanostructures are transferred into 1-D arrays of Co3O4 nanorods. The obtained 1-D Co3O4 nanostructures are then transformed into the corresponding analogous shaped 1-D arrays of porous cobalt sulfide (CoS1.0365) nanostructures using a wet chemical transformation method based on an ion exchange approach. As a proof-of-concept demonstration for the application, various shaped CoS1.0365 nanorod films synthesized are investigated as a Pt-free counter electrode in dye-sensitized-solar cells (DSCs). Among the various nanostructures, the thicker nanorod film synthesized using a chloride precursor has demonstrated the best electrocatalytic behavior toward triiodide reduction, which led to a short circuit current density of 18.04 mA cm-2 and energy conversion efficiency of 7.4% of the DSC. This photovoltaic performance is highly competitive to a current density of 18.26 mA cm-2 and energy. Conversion efficiency of 7.7% exhibited by the standard Pt counter electrode. This finding suggests the present strategy as a low cost deposition method to facilitate the application of non-precious metal-free counter electrodes in high performance DSCs. Chapter 4: Additionally, we have developed a novel, low-temperature, and general solution-based protocol, which works equally for deposition of most of the Metal sulfides (MS) nanostructured thin films.We present for the first time, the use of a general solution-based protocol chemically synthesized pristine MoS2 counter electrode (CE) in DSCs. DSCs based on a mechanically robust MoS2 CE with a molybdenite mineral-type structure exhibited a competitive power conversion efficiency of 7.01%, which is largely comparable to DSCs with Pt CEs (PCE = 7.31%). The MoS2 CE presented in this work is quite promising and is a prospective candidate to replace highly expensive Pt as a CE, owing to its comparable catalytic properties and most importantly, the ease of fabrication at extremely low temperatures. The films obtained by this protocol were crystalline and highly uniform. The films can be deposited on any desirable conductive as well as non-conductive substrates. Chapter 5: Furthermore, development of solution based anion exchange transformation mehods for 1-D nanotubes of Cobalt telluride nanostructures.Basically, tellurization is performed at high temperature in inert gas atmosphere, which is an expensive and complicated process. In an effort to develop an alternative strategy of tellurization, herein we report a thin film formation of self-standing cobalt telluride nanotubes on various conducting and non-conducting substrates using a simple binder-free synthetic strategy based on anion exchange transformation from a thin film of cobalt hydroxycarbonate nanostructures in aqueous solution at room temperature.After the ion exchange transformation of nanostructures, the film shows conversion from insulator to highly electrical conductive semimetallic characteristic. When used as a counter electrode in I3-/I- redox electrolyte based dye sensitized solar cells, the telluride film exhibits an electrocatalytic reduction activity for I3- with a demonstration of solar-light to electrical power conversion efficiency of 8.10%, which is highly competitive to the efficiency of 8.20% exhibited by a Pt-film counter electrode.It is believed that the ability of the proposed aqueous solution phase anion exchanged transformation strategy to generate 1-D nano-scaled structures of cobalt telluride offers new opportunities to synthesize various metal telluride nanostructures, and thus opens new prospects to extend their potential applications in various fields.

A study on advanced memristive devices for neuromorphic computing and artificial sensory memory Harshada Satish Patil

PATIL HARSHADA SATISH 세종대학교 대학원 2024 국내박사

Traditional computer architectures, optimized for deterministic information processing, struggle with natural, unstructured, and noisy data. In contrast, the human brain excels at recognizing patterns and filtering relevant information in complex environments. The desire to endow electronic systems with similar capabilities drives research in neuromorphic computing, which seeks to emulate brain functions using artificial circuits. A crucial component in this field is the memristor, a nanoscale electronic device. This work focuses on developing advanced memristors using organic, ferroelectric, and perovskite materials for data storage and bio-inspired applications. In the pursuit of advancing organic memristive devices, the devices need to address challenges related to environmental sensitivity, stability, and reproducibility of organic materials. To overcome challenges such as environmental sensitivity, stability, and reproducibility in organic memristive devices, incorporating inorganic nanoparticles as a protective layer is proposed. This approach enhances control over filament formation and rupture, improving device performance. We successfully fabricated a low-cost, solution-processed organic bulk heterojunction (P3HT-PCBM) with an inorganic (ZnO) capping layer, demonstrating reliable bipolar resistive switching and multilevel resistive switching up to four levels, suitable for efficient multilevel data storage. Memristor-based crossbar structure faces challenges such as crosstalk and sneak path currents, causing writing disturbances, reading inaccuracies, and increased power consumption. Traditional solutions using selection components complicate fabrication, necessitating non-linear I-V characteristics for selector- free devices. Metal oxide semiconductor memristors require high current levels, increasing sneak currents. Ferroelectric tunneling junctions (FTJs) offer lower current levels but are hindered by ultrathin layer depolarization fields. We propose a ferroelectric-semiconductor heterostructure device to address these issues. In BaTiO3-based heterojunctions, resistive switching properties are optimized at a BaTiO3 growth temperature of 550°C. These devices exhibit nonvolatile and synaptic behaviors with self-rectifying properties, reducing crosstalk without selectors. Dynamic polarization switching in BaTiO3 achieves linear conductance changes and a 91% recognition accuracy in artificial synapses, advancing neuromorphic computing applications. The advancement of AI technology requires biomimetic functions for complex tasks and challenging environments. Artificial nociceptors are crucial for enhancing humanoid robots' sensory responses to adverse conditions. CMOS-based sensors have limitations, prompting the exploration of organic- inorganic halide perovskites (OHPs) for flexible and scalable solutions. OHP- based diffusive memristors show exceptional threshold switching, high ION/IOFF ratios (104), and bending endurance over 102 cycles. These devices mimic biological nociceptor functions, making them essential for AI and robotics. These innovations highlight the potential of memristors in developing low- power, high-density crossbar arrays and neuromorphic computing platforms, advancing their integration into sophisticated AI systems. Keywords: Organic memristors, Inorganic protective layer, Ferroelectric/semiconductor heterostructure, Self-rectification, Artificial synapse, Flexible diffusive memristor, Organic-inorganic perovskite, Artificial nociceptor

I. Discovery of Orally Bioavailable BTK PROTACs to Overcome Drug Resistance in Haematological Cancers II. Novel Tetrahydroquinoline-Based Tricyclic CRBN Binders for Targeted Protein Degradation Vineetkumar B Patil : No subtitle

Vineetkumar B Patil 과학기술연합대학원대학교 한국화학연구원(KRICT) 2024 국내박사

I. 혈액암에서의 약물 내성 극복을 위한 경구 투여 가능 BTK PROTACs 개발 Bruton's Tyrosine Kinase (BTK)는 kinase 의 테크 그룹에 속하는 비수용체 tyrosine kinase 이다. BTK 는 B-세포와 관련된 악성 질환의 치료에 유효한 표적이므로 BCR 경로를 통해 B-세포의 발전에 중요한 역할을 한다. 이브루티닙은 BTK 표적 최초의 비가역 소분자 억제제로, 2013 년에 USFDA 에서 CLL, MCL, WM 치료를 위해 승인되었다. 초기 성공에도 불구하고, 이브루티닙 치료를 받는 환자의 약 3 분의 1 은 C481S 돌연변이로 인한 내성을 겪는다. 또한, 이브루티닙 치료는 출혈, 설사, 부정맥과 같은 부작용과 관련이 있으며, 이것은 EGFR, TEC, SRC 및 JAK 에 대한 off-target 의 빈번한 억제로 인해 발생한다. 선택성 문제는 2 세대 아칼라브루티닙와 자노브루티닙으로 조금은 해결되었지만, 약물 내성의 문제는 여전히 남아있다. 피토브루티닙은 USFDA 에 의해 승인된 3 세대 및 최초의 비공유성 억제제이다. 피토브루티닙은 성공적으로 C481S 돌연변이를 표적하지만, L528W 와 같은 C481 과 관련이 없는 돌연변이가 임상 시험 중 상당히 발생했다. PROTAC 과 같은 새로운 기술은 이러한 문제를 극복하기 위한 유망한 전략이며, 그에 따라 BTK PROTAC 은 산업 및 학문 연구에서 많이 쓰이고 있다. 따라서 앞서 언급한 문제를 극복하기 위해 경구 투여 가능한 BTK PROTAC 을 발견하고자 하였다. 우리는 in vitro 및 in vivo 에서 MT-802, ARQ-351, 및 이브루티닙보다 우수한 화합물 21 (UBX-382)의 발견을 이끌었다. 게다가 화합물 21 은 T474I 를 제외한 모든 알려진 BTK 돌연변이에 효과적이었다. 또한, 화합물 21 은 경구 투여시 WT 및 VI 이브루티닙 내성 C481S 돌연변이 BTK 를 모두 발현하는 쥐 이종이식 모델에서 탁월한 항종양 효과를 보여주었다. 이 연구은 새로운 BTK PROTAC 시리즈의 발견 전략, 화학적 합성 및 엄격한 생물학적 평가에 대한 강력하고 확고한 탐구를 제시한다. 주요단어(Key words): BCR, BTK, PROTACs, C481S 돌연변이, 경구 이용 가능, CLL, MCL, DLBCL, 약물 저항성 II. Novel Tetrahydroquinoline-Based Tricyclic CRBN Binders for Targeted Protein Degradation Targeted Protein Degradation (TPD) has emerged as a transformative strategy for addressing challenges related to small molecule inhibitors. Key TPD methodologies, including molecular glues (MG) and Proteolysis Targeting Chimera (PROTAC), leverage the function of E3 ligases, such as CRBN, VHL, MDM2, and so on. The pivotal role of CRBN is exemplified by its interaction with immunomodulatory imide drugs (IMiDs) like thalidomide, lenalidomide, and pomalidomide, which have demonstrated remarkable immunomodulatory effects. By incorporating these IMiDs as E3 motifs, PROTACs such as ARV-110, ARV-471, and NX-2127, have advanced their application in various cancer treatments, underscoring the critical significance of CRBN modulators (CELMoDs) in TPD technology. However, challenges related to drug resistance, CRBN downregulation, and teratogenicity have impeded the effectiveness of IMiD-based therapies, which can be extended to PROTAC technology as well. In response, our research endeavors have focused on the design of novel tetrahydroquinoline (THQ)-based tricyclic CRBN binders. Notably, the newly designed CRBN binders, KMG-1206-1208, exhibited a binding affinity to CRBN akin to that of lenalidomide. Remarkably, these binders demonstrated a non-degrading nature towards known neosubstrates including SALL4, thereby offering potential solutions to teratogenicity concerns. Integration into KBTP-04, a PROTAC incorporating our synthesized CRBN binder, facilitated the degradation of BTK in TMD8 cells. These findings significantly contribute to the ongoing advancements in TPD methodologies, laying a robust foundation for the development of VIII next-generation therapeutics and the improved management of complex disease states. Keywords: CRBN, degradation, ubiquitin proteasome system, immunomodulatory imide, thalidomide, molecular glue, neosubstrate II. 표적 단 백질 분해를 위한 Tetrahydroquinolin 기반 신규 Triicyclic CRBN 리간드 개발. Targeted Protein Degradation (TPD)는 소분자 억제제와 관련된 문제를 해결하기 위한 혁신적인 전략으로 나타났다. Molecular glue (MG) 및 Proteolysis Targeting Chimera (PROTAC)를 비롯한 주요한 TPD 기술은 CRBN, VHL, MDM2 등과 같은 E3 ligase 의 기능을 활용한다. CRBN 의 핵심 역할은 탈리도마이드, 레날리도마이드, 포말리도마이드와 같은 면역 조절제 약물 (IMiDs)와의 상호 작용으로 예시되며, 이 약물은 놀라운 면역조절 효과를 보여준다. 이러한 IMiD 를 E3 ligase motif 로 통합함으로써 ARV-110, ARV-471 및 NX-2127 과 같은 PROTAC 이 다양한 암 치료에 적용되었으며, TPD 기술에서 CRBN 모듈러(CELMoD)의 중요성을 강조했다. 그러나 약물 내성, CRBN 하향조절 및 최기형성과 관련된 문제는 IMiD 기반 치료의 효과를 방해했으며, 이는 PROTAC 기술에도 확장될 수 있다. 이에 대응하여, 우리는 새로운 tetrahydroquinoline (THQ) 기반의 삼환식 CRBN 바인더의 설계에 초점을 맞추었다. 특히, 새로 설계된 CRBN 바인더인 KMG-1206-1208 은 레날리도마이드와 유사한 CRBN 에 대한 결합 친화성을 나타냈다. 놀랍게도, 이러한 바인더는 SALL4 를 포함한 알려진 신기질에 대한 분해되지 않는 특성을 입증하여 최기형성 문제에 대한 잠재적인 해결책을 제공했다. 합성된 CRBN 바인더를 통합한 PROTAC 인 KBTP-04 에 통합하면 TMD8 세포에서 BTK 분해가 촉진되었다. 이러한 결과는 TPD 기술의 지속적인 발전에 크게 기여하며, X 차세대 치료법의 개발과 질병 상태의 향상된 관리에 대한 견고한 기초를 마련한다. I. Discovery of Orally Bioavailable BTK PROTACs to Overcome Drug Resistance in Haematological Cancers Bruton’s Tyrosine Kinase (BTK) is a non-receptor tyrosine kinase which belongs to the Tec family of kinases. BTK plays an important role in the development of B-cells via the BCR pathway, hence BTK is a valid target for the treatment of B-cell related malignancies. Ibrutinib is a first-inclass irreversible small molecule inhibitor of BTK, which was approved by the USFDA for the treatment of CLL, MCL, and WM in 2013. Despite early success, around one-third of the patients undergoing treatment with ibrutinib develop resistance due to C481S mutation. In addition, ibrutinib treatment is associated with side effects like bleeding, diarrhoea, haemorrhages, atrial fibrillation etc, this is due to promiscuous off-target inhibitions towards EGFR, TEC, SRC, and JAK. Although the selectivity issue was addressed to some extent by second-generation acalabrutinib and zanubrutinib, the problem of drug resistance is still prevalent. Pirtobrutinib is the third generation and the first non-covalent inhibitor approved by the USFDA. Pirtobrutinib successfully targeted the mutant C481S however, reports of mutations unrelating to C481 like L528W have occurred significantly during its clinical trials. Novel technologies like PROTACs have emerged as a promising strategy to overcome such issues, hence BTK PROTACs are the most sought-after in industrial and academic research. Hence, we initiated the discovery of orally available BTK PROTACs to overcome the aforementioned issues. Our drug discovery efforts led to compound 21 (UBX-382), which outperformed MT-802, ARQ-351, and ibrutinib in both IV in vitro and in vivo settings. Moreover, 21 was effective against all of the known BTK mutants except for T474I. In addition, compound 21 exhibited remarkable anti-tumor efficacy in murine xenograft models expressing both WT and ibrutinib-resistant C481S mutant BTKs when administered orally. This work presents a robust and assertive exploration of the discovery strategy, chemical synthesis, and rigorous biological evaluation of a series of novel BTK PROTACs

Anti-bacterial and Anti-cancer Activities of Silver and Gold Nanoparticles Synthesized using Sasa borealis and Agrimonia pilosa

PATIL MAHESHKUMAR PRAKASH Pukyong National University 2017 국내박사

Nanobiotechnology is emerging as a cutting-edge technology involving many academic disciplines like biology, chemistry, physics, material science and medicines. The word “nano” is derived from the Greek word nanos, which means “dwarf”. The size of a nanoparticle (NPs) is one billionth of a meter (10-9m), and materials with nanodimensions (1-100 nm) have significant activity compared to the same material in bulk form. Novel strategies are needed to improve efficiency of biomedicines. Presumptions are directed towards Nanobiotechnology-based applications in microbiology and cell biology. We have developed a green and eco-friendly route for synthesis of silver-silver chloride (Ag-AgCl) and gold (Au) NPs using medicinal plants (Sasa borealis, and Agrimonia pilosa). The visual observation indicates color change of reaction solution is the first sign of NPs formation, and confirmed by UV-visible spectroscopy. The shape, size and morphology of NPs were observed by transmission electron microscopy and field emission-scanning electron microscopy. The elemental composition and crystalline nature of synthesized NPs were analyzed by energy dispersive X-ray spectroscopy and X-ray diffraction spectroscopy, respectively. The synthesized NPs stability was determined by zeta potential study. The biomolecules present in plant extract and their interaction in NPs synthesis were studied by Fourier transform-infrared spectroscopy and gas chromatography-mass spectrometry. S. borealis leaves extract-mediated Ag-AgCl NPs were spherical, oval shape with particle size around 10-30 nm and -12.95 mV zeta potential value indicates NPs covered with negative charged material and which is responsible to prevent aggregation of NPs by electrostatic repulsion. The synthesized Ag-AgCl NPs were tested for antibacterial activity against Gram-positive (Listeria monocytogenes, Staphylococcus aureus, Staphylococcus saprophyticus) and Gram-negative bacteria (Escherichia coli, Pseudomonas putida). Among tested bacteria, Gram-positive bacteria (S. saprophyticus) show more sensitivity, and Gram-negative (P. putida) shows less sensitivity to the synthesized Ag-AgCl NPs. The cytotoxic activity was observed on gastric adenocarcinoma AGS cells. The concentration dependent cytotoxicity was observed and IC50 at 10 µg ml-1 recorded; same concentration was applied to check nuclear morphological observation by DAPI staining. A fragmentation and condensation is the characteristic of apoptosis which were observed in AGS cell. Likewise, S. borealis extract-mediated Au NPs were observed a spherical, oval shape with about 10-30 nm particle size. The toxic effect against embryonic kidney HEK293 cells and cytotoxic activity against gastric adenocarcinoma AGS cells were perform; upto 300 µg ml-1 of Au NPs were nontoxic to HEK293 cells and concentration dependent cell viability was observed on AGS cells. In DAPI staining, fragmentation and concensation of nuclear material were observed in treated AGS cells with IC50 concentration (120 µg ml-1). In next studies, A. pilosa aerial part extract was used to synthesize Ag-AgCl NPs from reduction of silver nitrate; small size of particles around 10-20 nm with a spherical and oval shapes were observed. The zeta potential value (-3.84 mV) indicates synthesized Ag-AgCl NPs carried negative charges. The antibacterial activity of synthesized Ag-AgCl NPs indicates, Gram-positive bacteria were more sensitive compared to Gram-negative bacteria. An FE-SEM study of Ag-AgCl NPs with and without treated bacterial samples indicates the possible mechanism behind bacterial growth inhibition is changes in cell wall morphology. Overall for the first time, these findings showed that S. borealis leaves extract-mediate Ag-AgCl NPs, Au NPs and A. pilosa aerial parts extract-mediated Ag-AgCl NPs have antibacterial and anticancer activity. This study will provide significant information for finding molecular mechanism behind bacterial and cancer cells death.

Oligo-Oleyl-Spermine Oligonucleotide Conjugate, Cationic-Amphiphiles, and Low-Molecular-Weight-Hydrogelators for Development of siRNA Delivery Systems : siRNA 전달 시스템 개발을 위한 올리고-올레일-스퍼민 올리고 뉴클레오타이드 결합체, 양이온성 지질 그리고 저

Patil, Sachin Prakash Pohang University of Science and Technology 2013 국내박사

Small interfering RNA (siRNA) represents the latest entry into the oligonucleotides therapeutics class. This technology is based on post- transcriptional gene silencing, more commonly referred to as RNAi, an endogenous, evolutionarily conserved, common pathway for regulation of gene expression. In the 1990s it was discovered that RNAi can be tapped artificially by addition of exogenous synthetic double-stranded small RNA sequences which, when exhibiting perfect complementarity to the mRNA sequence, lead to efficient mRNA cleavage (siRNA effect). Since this Nobel Prize-winning discovery, RNAi has become a widely used tool to probe gene function, routinely applied to cell culture systems and lower-organism models. However, siRNA itself cannot cross the cell membrane due to its inherent instability, large molecular weight and anionic nature. For this reason, a carrier that protects, delivers and unloads siRNA is required for successful gene silencing. The goal of this research was to develop potential siRNA delivery systems for their in vitro and in vivo applications based on cationic amphiphiles. Furthermore the delivery systems were constructed in three different ways (i) Oligo-oleyl-spermine oligonucleotide conjugate (ii) Cationic amphiphiles from nucleoside and phosphorylethanolamine (iii) Low molecular weight hydrogelators (LMWGs) from vitamins and nucleosides.

Design synthesis of double-decker silsesquioxane (DDSQ), perfluoroalkylation and γ- Amino acid

Patil, Kalpesh Changwon National University 2018 국내박사

Elucidating how bacteria sense phenols through structural analysis of transcription activators

Patil Vinod Vikas University of Science and Technology 2017 국내박사

Some bacteria are well equipped to utilize phenol as a carbon and energy source. Positive phenol-degradative gene regulators such as PoxR from Ralstonia eutropha and DmpR (CapR) from Pseudomonas putida are σ54-dependent AAA+ ATPase transcription activators that regulate the catabolism of phenols. The PoxR sensory domain detect phenols and relays signals for the activation of transcription. My thesis deals with understanding the structure and function of phenol responsive transcription activators. Based on function, these transcription activators can be divided into three domains viz. sensory domain, ATPase domain and DNA binding domain. The analysis of sensory domain revealed that it exists as a tightly intertwined homodimer with a ligand binding pocket buried inside, placing two Carboxyl termini on the same side of the dimer. Whereas the whole protein exists as a tetramer upon binding of phenol. H102 and W130 in case of PoxR and H100 and W128 in case of DmpR interact with the hydroxyl group of the phenols in a cavity surrounded by rigid hydrophobic residues on one side and a flexible region on the other. Each monomer has a V4R fold with a unique zinc-binding site. Upon binding of ligand, a shift at the Carboxyl terminal helix suggests that there is a possible conformational change. The linker region that connects sensory domain to central ATPase domain is helical. The first half of linker region (~225 residues) is quite rigid made up of helix that run parallel making slanting angles in a dimer. The latter half of linker is quite flexible having higher B-factor. The structural analysis shows that these residues are very critical for nucleotide binding. The binding of phenol produces shifts in the linker region causing Y233 and Q232 to make space for accommodation of nucleotide. The pi-pi stacking interaction of aromatic ring of tyrosine in nucleotide helps in binding of nucleotide in cleft. The phenol unbound form would not make any space for stable binding of nucleotide thus lowering overall ATPase activity and oligomerization. In absence of phenol the DmpR is in dynamic state of dimer and tetramer. The addition of phenol promotes the tetramer formation from dimers. The sensory domain interacts with ATPase domain from another dimer thus giving it a stability. The arrangement of ATPase domain in a tetramer is different from typical NTRC family proteins although the ATP binding cavity and key residues are quite similar. The AAA+ domains have the characteristic Walker A and Walker B motifs. The GAFTGA motif is located at the α/β subdomain surface at the tip of loop. ATPase domain exists as a monomer independently. The ATPase domain physically interacts with sensory domain. The GAFTGA (310-315) loop of ATPase domain interacts with the VNTLGI (53-58) R50 and D140 of sensory domain. The orientation of ATPase domain is different from the arrangement of reported ligand bound ATPases from NTRC family. There are other important residues of ATPase domain that have interaction with sensory domain (Sensory domain: N54, IL58, E59, D140, N145, D146, D194, 195, S198, N201, Y202, K204, and D206. ATPase domain: D298, A311, F312, P341, R342, A343, S346, R349, G360, N362, T364, R389). Sensory domain is critical for ATPase activity. Elimination of DNA binding domain adversely affects the ATPase activity. This thesis work is the first report about the structural arrangement of phenol-responsive transcription activator that can provide a structural basis of chemical effector binding for transcriptional regulation with broad implications for protein engineering, strain improvement and biosensor development.

(A) framework for secure smart greenhouse farming based on blockchain

Patil, Akash Suresh Pukyong National University 2018 국내석사

최근 다양한 분야에서 사물인터넷(IoT)이 광범위하게 사용되며 전통적인 농업 방법을 개선하여 품질과 수량 및 재정적인 부분을 효과적으로 향상시켰다. IoT의 개발은 농업과 농사 분야에서 새로운 방향을 제시하였으며 IoT에 기반하여 원격 모니터링 및 자동화 농업 분야 중 온실 농업 기술을 빠르게발전시켰다. 그러나 네트워크의 대규모 확장으로 인해 보안성 및 개인 정보보호에 대한 우려가 발생하였다. 이러한 보안 문제를 극복하기 위해 분산성,익명성, 보안성을 갖춘 블록체인 기술을 채택하여 본 논문에서는 IoT 및 블록체인 기술을 함께 사용하는 시스템 모델을 제안하였다. 제안하는 시스템 모델은 스마트 온실 농장을 기반으로 농가가 원격으로 데이터에 접근하고 스마트 온실을 모니터링 할 수 있는 시스템 모델이다. 시스템에서는 블록체인 기술을 사용하여 IoT 네트워크의 모든 참여 노드 간에 공유되는 트랜잭션의 분산 디지털 원장을 생성하였으며 IoT 장비들은 중앙에서 관리되는 Private 블록체인의 원장으로부터 이익을 얻을 수 있다. 한편 Public 블록체인은 공개적으로 접근 할 수 있는 분산 원장으로써 높은 리소스를 가지는 장치로 구현된 오버레이 네트워크에서 종단 간 보안 및 개인 정보의 안전성을 보장 하지만 계산 비용이 많이 들고 높은 에너지 사용이 필요하였다. 이에 따라 Contiki 기반 Cooja 시뮬레이터를 사용하여 시뮬레이션을 수행방법을 통해 제안하는 시스템 모델에서의 에너지 소비 및 시간 오버 헤드를 기반으로 결과를 평가하였다. In recent times, The Internet of Things are widely applied in various agricultural fields to improve the traditional method of farming, which enables effective results in terms of quality, quantity and financially. The development of the Internet of Things triggered a new direction of research in agriculture and farming domain. Simultaneously, the emerging greenhouse farming technology in agriculture based on Internet of Things used for remote monitoring and automation has been rapidly developed. But it still has a major concern about security and privacy, due to the large scale of disseminating nature of the network. To overcome from this security challenges we adopt the blockchain technology having attractive security features such as decentralization anonymity and security. In this thesis, we proposed a system model which shows the collaboration of IoT and blockchain technology. Our system model based on smart greenhouse farming, where farmer can remotely access data and monitor smart greenhouse. We use blockchain technology, which allows the creation of a distributed digital ledger of transactions that is shared among all participate nodes in IoT network. IoT devices benefits from a private blockchain, i.e. immutable ledgers, which is managed centrally in smart greenhouse. A Public blockchain is publicly accessible distributed ledgers which guarantee the end-to-end security and privacy implemented on an overlay network, created with high resource devices. Blockchain technologies are computationally expensive and required high energy resource. Lastly, we conduct our simulation using Contiki based Cooja simulator, where we approach our system model and evaluate the result based on energy consumption and time overhead.

Oxidative transformations of alkynes and allenes for cyclizations and cross-couplings

Patil, Dilip Vitthal 한양대학교 대학원 2017 국내박사

Efficient visualization and recognition of the cylinder in 3D point cloud

Rekhax, Patil 중앙대학교 첨단영상대학원 2017 국내석사