Dr. S. Murugavel
Professor & Head
Department of Physics
[email protected] or [email protected]
+91-9790084145
Google scholar: https://scholar.google.co.in/citations?user=024T-qEAAAAJ&hI=en
PROFILE
Research Areas: 17 years of Research experience
The main focus of my research is to determine the accurate and reliable 3-dimensional structure of Organic compounds of biological importance, analyse the biological activity and finally finding the drug for dengue fever, asthma, cancer activities, diabetic, skin allergy problems etc.,
Research areas include:
Crystallography, Crystal Growth, Spectroscopy, Computational Studies, Drug Design and Discovery, Molecular simulation
OUTCOME OF RESEARCH ACTIVITIES
Publications : 106 |
Patent received: 03 |
Ph.D Guided : 11 |
Ph.D ongoing : 03 |
H-Index : 12 |
i10-index : 13 |
Citations : 501 |
EDUCATION
Ph.D. (Crystallography), University of Madras, August 2010.
M.Phil. (Physics), Manonmanium Sundaranar University, Thirunelvelli, 2003.
M.Sc. (Physics), Sri Ramakrishna Mission Vivekananda College, Chennai, 1998.
B.Sc. (Physics), Sri Sankara Arts & Science College, Kanchipuram, 1996.
PROFESSIONAL EXPERIENCE – 22 years
Professor, Thanthai Periyar Government Institute of Technology, Vellore, Tamil Nadu, India, since August 2017
Associate Professor, Thanthai Periyar Government Institute of Technology, Vellore, Tamil Nadu, India from August 2014 to August 2017
Assistant Professor, Thanthai Periyar Government Institute of Technology, Vellore, Tamil Nadu, India from September 2007 to August 2014
Assistant Professor, Government College of Engineering, Bargur, Tamil Nadu, India from August 2001 to September 2007
TEACHING
COURSES DEVELOPED:
Engineering Physics (UG)
Materials Science (UG)
Physics for Civil Engineering (UG)
Physics for Electronics Engineering (UG)
Physics for Information Science (UG)
COURSES TAUGHT:
Engineering Physics (UG)
Materials Science (UG)
Physics for Civil Engineering (UG)
Physics for Electronics Engineering (UG)
Physics for Information Science (UG)
Semiconducting and Opto-electronic devices (UG)
RESEARCH ACTIVITIES
RESEARCH PROJECT
Inhibition of corona Virus (Covid-19) through ecological preparation of novel anti-viral potent compounds consisting quinolone thiazole hybrids by molecular hybridization approach by TNSCST, DOTE Campus, Chennai, 2021-22 to 2022-2023
PUBLICATIONS
RESEARCH PUBLICATIONS: 106
Recent Journal Papers ( Last five years):
1.Ruchika Sharma, Mulveer Singh, Palthad Jayarama Srijana, Badiadka Narayana, Balladka Kunhanna Sarojini, Ullal Likhitha, Saminathan Murugavel, Jayakumar Mohan Raj, Rajni Kant : Synthesis, characterization, quantum chemical calculation, Hirshfeld surface analysis and antibacterial activity of a co-crystal of 4-Aminopyridine: p-Hydroxybenzoic acid with a water molecule, J. mol. struct. Volume1284, 135309, 15 July 2023 (https://doi.org/10.1016/j.molstruc.2023.135309)
2.RaviKumar Chandrasekaran, Saminathan Murugavel, Tamilselvan Silambarasan, Computer Aided Drug Design of 1,2,3-Triazole Fused Bioactive Derivative Targeting Glucosamine-6-Phosphate Synthase (GlmS) – XRD, Computational Crystallography, and Molecular Simulation Approach,
Pol. A.Comp. Vol. 43, Pag. 3223-3239,21/04/2023
3.Neha Kumari, Ruchika Sharma, Archana Akaram Yadav, Sandeep Ashok Sankpal, Jayakumar Mohan Raj, Saminathan Murugavel, Rajni Kant, Synthesis, crystal structure, DFT/HF, Hirshfeld surface, and molecular docking analysis of 4-(tert-butyl)-4-nitro-1, 1-biphenyl, Euro. J.Chem. Vol.14, Pag. 90-98, 31/3/2023
4.Ruchika Sharma, Palthad Jayarama Srijana, Mulveer Singh, Badiadka Narayana, Balladka Kunhanna Sarojini, Ullal Likhitha, Saminathan Murugavel, Jayakumar Mohan Raj, Rajni Kant, Supramolecular co-crystal of 4-dimethyl aminopyridine with Picric acid (4DMAP: PA): Synthesis, single crystal investigation, HF/DFT inspection, Hirshfeld surface and antifungal activity, J. mol. Struct. Vol. 1270, Pag.133921, 15/12/2022
5.Mulveer Singh, Saminathan Murugavel, Ravikumar Chandrasekaran, Rajni Kant, Quantum, Hirshfeld surface, crystal voids, energy framework and molecular docking analysis of two halogen-containing benzimidazole-2-thione structures, Mol.C.Liq.Cry, Vol.739, Pag.127-141, 01/09/2022
6.Ruchika Sharma, Sandeep Ashok Sankpal, Pradeep Jangonda Patil, Saminathan Murugavel, Sonachalam Sundramoorthy, Rajni Kant, Synthesis, X-ray crystal structure, DFT, Hirshfeld surfaces, energy frameworks, and molecular docking analysis of a bicyclic ortho-aminocarbonitrile derivative, Euro. J.Chem.Vol.13, Pag.135-144, 30/06/2022.
7.Saminathan Murugavel, Perumal Vasudevan, RaviKumar Chandrasekaran, Vellingiri Archana, Alagusundaram Ponnuswany, Synthesis, crystal structure elucidation, DFT analysis, drug-likeness and ADMET evaluation and molecular docking studies of triazole derivatives: Binary inhibition of spike protein and ACE2 receptor protein of COVID-19,J.Chin.Che.So. Vol.69, Pag.884-900, June 2022.
8.RaviKumar Chandrasekaran, S Murugavel, Mridula Guin, T Silambarasan, Crystal structure, Hirshfeld, computational biomolecular investigations, and MTT assay studies of amino pyrimidine derivative as EGFR kinase domain inhibitor, J. mol. Struct. Vol.1254,Pag.132416, 15/04/2022
9.Gopal Sharma, Sumati Anthal, P Akhileshwari, HM Vinusha, S Bindya, MA Sridhar, Muneera Begum, Ravikumar Chandrasekaran, Murugavel Saminathan, Rajni Kant, Synthesis, crystal structure, molecular docking, lattice energy and Hirshfeld surface analysis of an antituberculosis drug of (E)-2-methoxy-5-(((6-methoxypyridin-3yl)imino)methyl)phenol, , Mol.C.Liq.Cry, Vol.737, Pag.65-80,13/04/2022.
10.RaviKumar Chandrasekaran, Saminathan Murugavel, Tamilselvan Silambarasan, Synthesis, quantum chemical, and molecular modeling investigations of 1, 2, 3‐triazole fused dicarboxylate bioorganic derivative as angiotensin‐converting enzyme inhibitor, J.Chin.Che.So. Vol.69, Pag.569-584, March 2022.
11.C Ravikumar, Silambarasan Tamil Selvan, Murugavel Saminathan, Damir A Safin, Crystal structure, quantum computational, molecular docking and in vitro anti-proliferative investigations of 1H‐imidazole‐2‐thione analogues derivative, , J. mol. Struct. Vol. 1250, Pag.131833, 15/02/2022.
12.R Sharma, M Singh, K Kamal, N Ghatpande, M Shaikh, J Jadhav, S Murugavel, R Kant, Synthesis, crystal structure, Hirshfeld surface, crystal voids, energy frameworks, DFT and molecular docking analysis of (2, 6-dimethoxyphenyl) acetic acid, A.J.Chem. Vol.4. Pag.1-16, 2022.
13.Maria G Babashkina, Antonio Frontera, Alexander V Kertman, Yasemin Saygideger, Swaminathan Murugavel, Damir A Safin, Favipiravir: insight into the crystal structure, Hirshfeld surface analysis and computational study, J.Ir.Chem.So. Vol.19, Pag.85-94, January 2022
14.Sonachalam Sundramoorthy and Rajni Kant, Ruchika Sharma, Sumati Anthal, Nitin G. Ghatpande, Mahidansha M. Shaikh, Jagannath S. Jadhav, Saminathan Murugavel, Crystal structure, Hirshfeld surface, Energy framework and Molecular docking analysis of 4-(methoxyphenyl)acetic acid, A.J.Chem. Vol. 3, Pag.333-347, 16/12/2021
15.Mulveer Singh, Sumati Anthal, Ravikumar Chandrasekaran, Saminathan Murugavel, Sandeep S Sankpal, Madhukar B Deshmukh, Rajni Kant, Crystallographic Structure and in Silico Molecular Docking Analysis of 2-Cyclohexylidene-Hydrazine-Carbothiomide, Cry.Rep. Vol.66, Pag.1306-1310, Dec. 2022
16.R. Kant M. Singh, S. Anthal, P. Akhileshwari, M. A. Sridhar, H. M. Vinusha, S. Bindya, M. Begum, R. K. Chandrasekaran, M. Saminathan, Synthesis, Crystal Structure, Hirshfeld Surface, Energy Framework and Molecular Docking of 2-(((6-Methoxy pyridin-3-yl)imino)methyl)Phenol, T.Glo.J.Sci.Fr. Vol. 20, Pag. 9-20, 03/09/2021
17.K Saranya, S Murugavel, Synthesis of novel thiophene fused pyrazoline-thiocyanatoethanone derivative: Spectral, DFT, pharmacological, docking and in vitro antibacterial studies, J. mol. Struct. Vol.1229, Pag.129487, 005/04/2021
18.Murugavel Saminathan, Mohan Raj Jayakumar, Ravikumar Chandrasekaran, Ranganathan Raja, Jaabil George, Ponnuswamy Alagusundaram, Synthesis, spectral, crystal structure, drug-likeness, in silico, and in vitro biological screening of halogen [Cl, Br] substituted N-phenylbenzo[g]indazole derivatives as antimicrobial agents, J.Het.Chem. Vol.58, Pag. 841-863, March 2021.
19.S Murugavel, S Deepa, C Ravikumar, R Ranganathan, Ponnusamy Alagusundaram, Synthesis, structural, spectral and antibacterial activity of 3, 3a, 4, 5-tetrahydro-2H-benzo [g] indazole fused carbothioamide derivatives as antibacterial agents, J. mol. Struct. Vol.1222, Pag.128961, 15/12/2020.
20.Murugavel Saminathan, Saranya Kanagarajan, Ravikumar Chandrasekaran, Archana Sivasubramaniyan, Ranganathan Raja, Ponnusamy Alagusundaram, Synthesis, structural, DFT investigations and antibacterial activity assessment of pyrazoline‐thiocyanatoethanone derivatives as thymidylate kinase inhibitors, J.Chin.Che.So. Vol.67, Pag.1100-1112, June 2020
21.Ruchika Sharma, Sumati Anthal, Nitin G Ghatpande, Mahidansha M Shaikh, Jagannath S Jadhav, Saminathan Murugavel, Sonachalam Sundramoorthy, Rajni Kant, Crystal structure, Hirshfeld surface, Energy framework and Molecular docking analysis of 4-(methoxyphenyl) acetic acid , J.Chin.Che.So. 2020
22.C Ravikumar, S Murugavel, Structural correlation and computational quantum chemical explorations of two 1, 2, 3-triazolyl-methoxypyridine derivatives as CYP51 antifungal inhibitors, J. Str.Chem. Vol. 30, Pag. 2225-2243,Dec. 2019
23.S Murugavel, N Manikandan, C Ravikumar, K Naveen, PT Perumal, Synthesis, Structural Commentary, Supramolecular Architecture and Molecular Docking Investigations of a Novel Thiophene-Fused 1,2,3,4-Tetrahydroisoquinoline Derivative as a Potent Anti-Cancer Agent, J. Str.Chem. Vol. 60, Pag. 1143-1149, July 2019
24.S Murugavel, Chandrasekaran Ravikumar, G Jaabil, Ponnuswamy Alagusundaram, Synthesis, computational quantum chemical study, in silico ADMET and molecular docking analysis, in vitro biological evaluation of a novel sulfur heterocyclic thiophene derivative containing 1,2,3-triazole and pyridine moieties as a potential human topoisomerase IIα inhibiting anticancer agent, Comp. Bio.Chem. Vol. 79 Pag. 73-82, 01/04/2019
25.Helda Malarkodi Jesudoss, Murugavel Saminathan, Rosaline Ezhilarasi Jesudoss, Dinesh Murugan, Ponnuswamy Alagusundaram, Crystal Structure, Spectral, Electronic, NLO Studies, and Bioactivity of 3′-(1-Benzyl-5-Methyl-1H-1,2,3-Triazole-4-Carbonyl)-4′-(4-Bromophenyl)-1′-Methyl-2H-Spiro [Acenaphthylene-1,2′-Pyrrolidine]-2-One, Braz.J.Phy. Vol.49. Pag.29-43. 15/02/2019
26.S Murugavel, C Ravikumar, G Jaabil, Ponnusamy Alagusundaram, Synthesis, crystal structure analysis, spectral investigations (NMR, FT-IR, UV), DFT calculations, ADMET studies, molecular docking and anticancer activity of 2-(1-benzyl-5-methyl-1H-1,2,3-triazol-4-yl)-4-(2-chlorophenyl)-6-methoxypyridine – A novel potent human topoisomerase IIα inhibitor, J. mol. Struct. Vol. 1176, Pag.729-742, 15/01/2019
27.S Murugavel, S Sundramoorthy, R Subashini, P Pavan, Synthesis, characterization, pharmacological, molecular modeling and antimicrobial activity evaluation of novel isomer quinoline derivatives, , J. Str.Chem. Vol.29. Pag.1677-1695. Dec.2018
28.Helda Malarkodi, Murugavel Saminathan, Rosaline Ezhilarasi, Dinesh Murugan, Alagusundaram Ponnuswamy, Molecular Structure, Spectral, Electronic and Thermodynamic, First‐Order Hyperpolarizability, NBO and Molecular Docking Studies of Novel Acenaphthylene Pyrrolidine Derivative, J. Chem.Sel. Vol.3, Pag.11552-11564, 08/11/2018
29.George Jaabil, Raja Ranganathan, Alagusundaram Ponnuswamy, Perumal Suresh, Vellasamy Shanmugaiah, Chandrasekaran Ravikumar, Saminathan Murugavel A Green and Efficient Synthesis of Bioactive 1, 2, 3 ‐ Triazolyl‐Pyridine/Cyanopyridine Hybrids via One‐Pot Multicomponent Grinding Protocol, J. Chem.Sel. Vol. 3, Pag. 10388-10393. 09/10/2018
30.Raja Ranganathan, Sivasubramaniyan Archana, Murugan Dinesh, George Jaabil, Sangaraiah Nagarajan, Alagusundaram Ponnuswamy, Kanagarajan Saranya, Saminathan Murugavel, A Smart and Efficient One‐Pot Green Synthesis of Novel 1, 2, 3‐Triazolyl Pyrazoline‐/Indazolyl‐Carbothioamide Hybrids under Solvent‐Free Grinding Strategy at Room Temperature, J. Chem.Sel. Vol. 3. Pag. 10091-10095, 21/09/2018
31.Rajni Sharma Devinder Kumar, Jayashree Avvadukkam, Narayana Badiadka, Sarojini Balladka Kunhana, Ravikumar Chandrasekaran, Murugavel Saminathan, Anthal Sumati, RajniKant,Crystal structure and molecular docking studies of 1,2,4,5-tetraaryl substituted imidazoles, Hetr. Com. Vol. 24, Pag. 205-210, 23/06/2018
32.Rajni Kant, Ratika Sharma , A. Jayashree , B. Narayana , B. K. Sarojini , C. Ravikumar , S. Murugavel , Sumati Anthal, Synthesis, X-Ray Structure and Molecular Docking Analysis of Two Novel 1,2,4,5-Tetrasubstituted Imidazole Derivatives, Int. J.Bio Phy. Vol.2, Pag. 9-15, 2018
PATENTS: Received 3 Nos
1.Patent No: 42/2022, Date of filing: 16 October 2022, Grant date: 21 October 2022, An ecofriendly synthesis of novel 1,2,3 triazolylpyrazoline and Indazolyl-carbothiamide hybrids (Indian Patent Application No. 202241059027).
2.Patent No: 132618, Date of filing: 11 May 2022, Grant date: 6 April 2023, Ultrasonic flaw detector (Indian Patent Application No. 364049-001).
Contributors: Dr.S.Murugavel & Dr.J.Sreerambabu
3.Patent No: 124870, Date of filing: 11 May 2022, Grant date: 12 January 2023, Solar helmet (Indian Patent Application No. 364050-001).
Contributors: Dr.S.Murugavel & Dr.J.Sreerambabu
Ph.D STUDENTS: GRADUATED-11 NOS
Vijayakumar S (2017) X-Ray Crystallographic and Molecular Docking studies on some organic compounds of medicinal importance
Lakshmanan D (2017) X-Ray Crystal structure investigations and Molecular Docking studies on some organic compounds of biological importance
Vetrivelan V (2017) Crystal structure, Spectral, Biological activity, Molecular Docking and DFT studies of some novel benzene sulfonamide derivatives
Madhan raj R (2017) X-Ray Crystal structure analysis and Molecular Docking studies on few organic molecules of Pharmaceutical interest
Jacob Prasanna Stephen C S (2018) Structural elucidation, Spectroscopic investigations, Anioxidant studies, Calf hymus DNA Interactions and molecular docking analysis of some novel chloroquinoline derivatives
Sundramoorthy S (2019) Structural, Spectral, DFT, In silico and In vitro studies of some novel Chloroquinolone analogues
Helda Malarkodi J (2020) Characterization studies of novel 1,2,3-Thiazole derivatives containing purrolidine and acenapthalene moieties as potent antimicrobial agents
Ravikumar C (2020) Synthesis and characterization studies of some novel 1,2,3-Triazole fused methoxypyridine derivatives as potent anticancer lead compounds
Dr saranya K (2020) Synthesis, characterization, Crystal structure, Molecular Docking and Antibacterial evaluation of novel Pyrazoline fused thiocynatoethanone derivatives
Dr Deepa S (2022) Synthesis, structural characterization, In silico and In vitro Biological evaluation of novel Indazole fused Carbothiamide derivatives as Antibacterial agents
Mohan Raj J (2022) Synthesis, Spectra, Crystal Structure, Drug-likeness, In silico and In vitro biological screening of halogen [Cl, Br] substituted N-Phenylbenzo[g]indazole derivatives as Antimicrobial agents
Ph.D STUDENTS: ONGOING – 3 NOS
Manikandan.N – Reg. year (2011-JAN)- Status-Synopsis Submitted
Adhikesavan.M -Reg.year (2021-JUL)-Status- Course Work
Viswanathan.Y-Reg.year (2023-JUL)-Status Course Work
CONFERENCE PAPERS:
1.Ravikumar, S. Murugavel, V.Rajni Swamy, Investigations of crystal packing by Hirshfeld surface, energy framework methods and protein-ligand interaction analysis of the 1,2,3-triazole fused pyridine derivative as a chemotherapeutic lead compound, Conference Proceedings and Collection of the 1st National Online Conference on Advances in Functionalized Materials, 2020, 082, ISBN No. 978-93-5419-177-0
2.Ravikumar, S Aksshita, S. Murugavel, Investigating the molecular interactions and effectiveness of various drugs targeting COVID-19 main protease from CORONA virus through in-silico approach, Conference Proceedings and Collection of the 1st National Online Conference on Advances in Functionalized Materials, 2020, 089, ISBN No. 978-93-5419-177-0
3.Saranya, S. Murugavel, Significance of Thiocyanate moiety in antibacterial drug design, Conference Proceedings and Collection of the 1st National Online Conference on Advances in Functionalized Materials, 2020, 116, ISBN No. 978-93-5419-177-0
4.Mohan Raj, S. Murugavel, Synthesis, crystal structure and biological activity of novel Pyrazoline/ Indazolyl-Carbothioamide derivatives, Conference Proceedings and Collection of the 1st National Online Conference on Advances in Functionalized Materials, 2020, 121, ISBN No. 978-93-5419-177-0
5.Deepa, S. Murugavel, Synthesis, crystal structure, molecular docking and biological activity of pyrazole-Carbothiomide, Conference Proceedings and Collection of the 1st National Online Conference on Advances in Functionalized Materials, 2020, 122, ISBN No. 978-93-5419-177-0
6.Ravikumar, S. Murugavel , T. Silambarasan, Identifying vital antimalarial therapeutic nature of 1,2,3-triazolyl derivatives through in silico docking and molecular dynamics, Conference Proceedings and Collection of the 1st National Online Conference on Advances in Functionalized Materials, 2020, 126, ISBN No. 978-93-5419-177-0
BOOKS AUTHORED
S.No | Title of the Book | ISBN No | Publisher name |
1 | Materials science | 9788193788394 | VRB Publishers |
2 | Physics for Electronics Engineering | 9789389027136 | VRB Publishers |
3 | Physics for Information Science | 9789389027129 | VRB Publishers |
4 | Physics for Civil Engineering | 9789389027143 | VRB Publishers |
AWARDS
Received Radhakrishnan Gold Medal award from GEPRA organization for the intense contribution towards research and teaching in 2013.
Received APJ. Abdul Kalam award from Marina labs, Chennai for scientific excellence in 2016.
Received Outstanding Researcher and Scholar Icon award from Jupiter Scholar Award for Excellence in Research (JSAER), Chennai for research excellence in 2017.
OUTREACH ACTIVITIES
SEMINARS/WORKSHOP/CONFERENCES ORGANISED
1.Workshop Coordinator for Two-week ISTE short term Training Programme on Engineering Physics Conducted by IIT-Bombay from December 8-18, 2015
2.AICTE sponsored “Two days national level online conference on Advances in functionalized materials” [NCAFM 2020] 8th October& 9th October 2020
3.AICTE Sponsored “Two-week online Faculty Development programme on Advanced Physics for Engineers” 4th Nov 2020 to 17th Nov 2020
4.AICTE Sponsored “Two-week online Faculty Development programme on Advanced Physics for Engineers” 25th Nov 2020 to 8th Dec 2020
INVITED TALK
1.Delivered lecture on Superconductivity & its applications at ARM College of Engg & Tech, Kanchipuram on 27.02.2016.
2.Delivered lecture on Current trends in nano technology at New Prince Shri Bhavani College of Engg & Tech, Chennai on 23.04.2016
3.Delivered lecture on Quantum Physics at UCEA, Arni on 11.05.2016.
4.Delivered lecture on Recent trends in crystallography at SCSVM, Kanchipuram on 18.05.2016.
5.Delivered lecture on LASERs & its applications at ARM College of Engg & Tech, Kanchipuram on 26.11.2016.
6.Delivered lecture on Crystallography & Drug Design at P. T. Lee Chengalvaraya Naicker College of Engg & Tech, Kanchipuram on 12.04.2017
7.Delivered lecture on New Engineering Materials at Arjun College of Tech, Coimbatore on 29.04.2017.
8.Delivered lecture on Vibrational Spectroscopy at SCSVM, Kanchipuram on 12.06.2017.
9.Delivered Expert talk on Basic Physics in day to day life at SRMIST, Ramapuram, Chennai on 28.07.2022
10.Delivered Guest lecture on Concepts of Science in day to day life at SRMIST, Ramapuram, Chennai on 14.10.2022
11.Presented Invited talk on Synthesis, Crystallographic studies, Drug-likeness and ADMET evaluation and Molecular docking studies of Triazole deivatives: Binary inhibition of Spike protein and ACE2 receptor protein of COVID-19 at 49th National Seminar on Crystallography, Department of Physics, University of Jammu on 30.12.2022
12.Delivered Guest lecture on Concepts of Physics in day to day life at Easwari Engineering College, Chennai on 21.01.2023
ADMINISTRATIVE ACTIVITIES
INSTITUTE LEVEL
Chief Faculty Advisor for first year students
Nodal Officer for TNEA cum College admission
Autonomous coordinator
Chairman, Antidrug committee
Member, College level Purchase Committee
UNIVERSITY LEVEL
Member for framing Physics course Syllabus at Anna University
Member of Board of Studies of the Faculty of Science and Humanities for the Non-Autonomous Colleges affiliated to Anna University
Appointed as Anna University nominee for conducting academic council meeting at Er. Perumal Manimegalai College of Engineering, Hosur
Member of Board of Studies of Physics, Thiruvalluvar University, Vellore
Appointed as Anna University nominee for conducting academic council meeting at R M K College of Engineering and Technology, Thiruvalluvar, Chennai
Member of Board of Studies of Science and Humanities for the Veltech Hign Tech Engineering College, Chennai
Appointed as DoTE nominee for conducting academic council meeting at MOHAMMED Sathak A.J. College of Engineering, Chennai