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Chandrasekaran J, Elumalai S, Murugesan V, Kunjiappan S, Pavadai P, Theivendren P. Computational design of PD-L1 small molecule inhibitors for cancer therapy. Mol Divers 2023; 27:1633-1644. [PMID: 36006501 DOI: 10.1007/s11030-022-10516-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 08/14/2022] [Indexed: 10/15/2022]
Abstract
Drug repurposing opens new avenues in cancer therapy. Drug repurposing, or finding new uses for existing drugs, can substantially reduce drug discovery time and costs. Cheminformatics, genetics, and systems biology advances enable repositioning drugs. Clinical usage of PD-1/PD-L1 blocking has been approved because of its efficacy in improving prognosis in select groups. The PD-1/PD-L1 axis was considered to represent a mechanism for tumour evasion of host tumour antigen-specific T-cell immunity in early preclinical research. The expression of PD-L1 in cancer cells causes T lymphocytes to become exhausted by transmitting a co-inhibitory signal. A better understanding of how PD-L1 is regulated in cancer cells could lead to new therapeutic options. In this view, the study was aimed to repurpose the existing FDA-approved drugs as a potential PD-L1 inhibitor through e-Pharmacophore modelling, molecular docking and dynamic simulation. e-Pharmacophore screening retrieved 324 FDA-approved medications with the fitness score ≥ 1. The top 10-docked FDA candidates were compared with IN-35 (Clinical trial candidate) for its interaction pattern with critical amino acid residues. Mirabegron and Indacaterol exhibited a greater affinity for PD-L1 with docking scores of - 9.213 kcal mol-1 and - 8.023 kcal mol-1, respectively. Mirabegron retain interactions at all three major hotspots in the PD-L1 dimer interface similar to IN-35. MM-GBSA analyses indicated that Mirabegron uses less energy to create a more stable complex and retains all of the inhibitor's positive interactions found in clinical trial ligand IN-35. Molecular dynamics simulation analysis of the Mirabegron complex showed a similar pattern of deviation in correlation with IN-35, and it retains the interaction with the active key amino acids throughout the simulation time. Our present study has shown Mirabegron as a powerful inhibitor of PD-L1 expression in cancer cells using a drug-repurposing screen.
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Affiliation(s)
- Jaikanth Chandrasekaran
- Department of Pharmacology, School of Pharmacy & Technology Management, SVKM'S NMIMS University, Secunderabad, 500017, India.
| | - Senthilkumar Elumalai
- Department of Pharmacology, PSG College of Pharmacy, Peelamedu, Coimbatore, 641004, India
| | - Vidya Murugesan
- Department of Chemistry and Biochemistry, Science and Commerce, M S Ramaiah College of Arts, Bengaluru, 560054, India
| | - Selvaraj Kunjiappan
- Department of Biotechnology, Kalasalingam Academy of Research and Education, Krishnankoil, 626126, India
| | - Parasuraman Pavadai
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, M.S. Ramaiah University of Applied Sciences, Bengaluru, 560054, India
| | - Panneerselvam Theivendren
- Department of Pharmaceutical Chemistry, Swamy Vivekanandha College of Pharmacy, Tiruchengodu, 637205, India
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V S J, Shaji S, Natarajan G, Sulthan Alavudeen S, Balasubramanian C, Senthilkumaran G, Rajarathinam V, Devaraju P, Murugesan V. POS-100 AN UNUSUAL SITE FOR A COMMON DISEASE IN A RENAL TRANSPLANT RECIPIENT. Kidney Int Rep 2022. [DOI: 10.1016/j.ekir.2022.07.118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Rajarathinam V, Gopalakrishnan N, Senthilkumaran G, Vs J, Murugesan V, Balasubramanian C, Devaraju P, Thanigachalam D, Solomon D, Moses Lamech T, Palaniselvam S. POS-021 COVID VACCINE ASSOCIATED GLOMERULAR DISEASES- A CASE SERIES. Kidney Int Rep 2022. [DOI: 10.1016/j.ekir.2022.07.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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Venkatachalam N, Palanichamy M, Arabindoo B, Murugesan V. Retraction notice to Enhanced photocatalytic degradation of 4-chlorophenol by Zr4+ doped nano TiO2 Journal of Molecular Catalysis A: Chemical Volume 266, Issues 1–2, 2 April 2007, Pages 158-165. Molecular Catalysis 2022. [DOI: 10.1016/j.mcat.2022.112616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Balasubramanian C, Natarajan G, Senthilkumaran G, Devaraju P, Murugesan V, Vs J, Rajarathinam V, Lamech T, Thanikachalam D, Kamalakannan G, Shaji S, Kannan B, Rajendran M, Rajendran P. POS-102 INCIDENCE, MICROBIOLOGICAL SPECTRUM AND OUTCOME OF ACUTE PERITONITIS IN CONTINUOUS AMBULATORY PERITONEAL DIALYSIS PATIENTS. Kidney Int Rep 2022. [DOI: 10.1016/j.ekir.2022.07.120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Devaraju P, Murugesan V, Vs J, Balasubramanian C, Senthilkumaran G, Rajarathinam V, Natarajan G, Rajendran P, Dakshinamoorthy S, Jeyachandran D, Thanikachalam D, Arumugam V, Rajendiran A, Durai R, Solomon D. POS-101 A STUDY ON BACTERIAL INFECTIONS IN KIDNEY TRANSPLANT RECIPIENTS. Kidney Int Rep 2022. [DOI: 10.1016/j.ekir.2022.07.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Kouwenhoven K, Elwakil I, Wingerden JV, Murugesan V, Thoen DJ, Baselmans JJA, Visser PJD. Model and Measurements of an Optical Stack for Broadband Visible to Near-Infrared Absorption in TiN MKIDs. J Low Temp Phys 2022; 209:1249-1257. [PMID: 36467123 PMCID: PMC9712414 DOI: 10.1007/s10909-022-02774-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 06/17/2022] [Indexed: 06/17/2023]
Abstract
Typical materials for optical Microwave Kinetic Inductance Detetectors (MKIDs) are metals with a natural absorption of ∼ 30-50% in the visible and near-infrared. To reach high absorption efficiencies (90-100%) the KID must be embedded in an optical stack. We show an optical stack design for a 60 nm TiN film. The optical stack is modeled as sections of transmission lines, where the parameters for each section are related to the optical properties of each layer. We derive the complex permittivity of the TiN film from a spectral ellipsometry measurement. The designed optical stack is optimised for broadband absorption and consists of, from top (illumination side) to bottom: 85 nm SiO2, 60 nm TiN, 23 nm of SiO2, and a 100 nm thick Al mirror. We show the modeled absorption and reflection of this stack, which has >80% absorption from 400 to 1550 nm and near-unity absorption for 500-800 nm. We measure transmission and reflection of this stack with a commercial spectrophotometer. The results are in good agreement with the model.
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Affiliation(s)
- K. Kouwenhoven
- SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
- Department of Microelectronics, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
| | - I. Elwakil
- SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
| | - J. van Wingerden
- Else Kooi Laboratory, Delft University of Technology, Feldmannweg 17, 2628 CT Delft, The Netherlands
| | - V. Murugesan
- SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
| | - D. J. Thoen
- Department of Microelectronics, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - J. J. A. Baselmans
- SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
- Department of Microelectronics, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
| | - P. J. de Visser
- SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
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Srikakulam N, Guria A, Karanthamalai J, Murugesan V, Krishnan V, Sundaramoorthy K, Saha S, Singh R, Victorathisayam T, Rajapriya V, Sridevi G, Pandi G. An Insight Into Pentatricopeptide-Mediated Chloroplast Necrosis via microRNA395a During Rhizoctonia solani Infection. Front Genet 2022; 13:869465. [PMID: 35706449 PMCID: PMC9189367 DOI: 10.3389/fgene.2022.869465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
Sheath blight (ShB) disease, caused by Rhizoctonia solani, is one of the major biotic stress-oriented diseases that adversely affect the rice productivity worldwide. However, the regulatory mechanisms are not understood yet comprehensively. In the current study, we had investigated the potential roles of miRNAs in economically important indica rice variety Pusa Basmati-1 upon R. solani infection by carrying out in-depth, high-throughput small RNA sequencing with a total data size of 435 million paired-end raw reads from rice leaf RNA samples collected at different time points. Detailed data analysis revealed a total of 468 known mature miRNAs and 747 putative novel miRNAs across all the libraries. Target prediction and Gene Ontology functional analysis of these miRNAs were found to be unraveling various cellular, molecular, and biological functions by targeting various plant defense-related genes. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to validate the miRNAs and their putative target genes. Out of the selected miRNA-specific putative target genes, miR395a binding and its cleavage site on pentatricopeptide were determined by 5’ RACE-PCR. It might be possible that R. solani instigated chloroplast degradation by modulating the pentatricopeptide which led to increased susceptibility to fungal infection.
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Murugesan V, Amarnath DJ, Shanmugam P. Investigation on Water Hyacinth in Anaerobic Co-Digestion for Biogas Production: A measure to Reduce Kosavampatti and Phoosur Lake Municipal Solid Waste Loading. Nat Env Poll Tech 2022. [DOI: 10.46488/nept.2022.v21i01.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The main aim of this study was to evaluate the lab scale, microbe-enhanced biogas production from water hyacinth blended with poultry waste and cow dung. A mesophilic anaerobic two-stage continuous reactor was set up to study the co-digestion for enhanced biogas production. The optimized mixing ratio of cow dung, water hyacinth, and poultry litter (2:1:1; 4:3:1 and 5:2:1) was used along with the effective microbial solution in a two-stage continuous reactor. The biogas yield was maximum in the 2:1:1 blend than the blends with a mixing ratio of 4:3:1 and 5:2:1. The reactor-loading rate was 4 and 5 g.L-1.day-1 with a retention time of 30 and 60 days respectively. The two-stage anaerobic digestion helps in controlling toxicity by acidogenesis and enhances energy production, thereby proving to be a technology that prevents environmental deterioration and enhances energy recovery, both of which are twin issues that need scientific attention. Maximum specific biogas of 0.128 Nm.L.g-1 of Volatile solid reduction (VSR) in hydrolyzer and 0.205 Nm.L.g-1 of VSR in methanizer was obtained at an optimized Carbon/Nitrogen (C/N) ratio of 20.8. The co-digestion of protein-rich waste with a carbon-rich source offers a reduced acclimatization period in the hydrolyzer with an increased C/N ratio, thereby increasing the biogas yield as observed in the methanizer. Several other parameters including Ammonia level, Volatile Fatty Acids influenced by the reactor alkalinity also determine the biogas yield. With increased alkalinity, free ammonia increases and may be inhibitory for anaerobic fermentation and may be toxic for methanogenic bacteria, thereby contributing to the reduction in biogas yield. The present investigation has led to a novel biogas and power-producing clean development mechanism (CDM) for the first time from a heterogeneous mixture of animal excreta and plant waste (livestock droppings, cow dung, and water hyacinths). The waste samples have been collected from sewage and sullage polluted Kosavampatti Lake and Phoosur lake in Namakkal district of Tamilnadu, India therein ending up in a high quantity of CO2 mitigation.
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Somasundaram K, Thoppalan B, Chellaiah V, Kumar RPS, Murugesan V, Thirumavalavan S. Clinical characteristics and immunosuppression management in kidney transplant recipients infected with severe acute respiratory syndrome coronavirus 2 infection - An observational study. Indian J Transplant 2022. [DOI: 10.4103/ijot.ijot_68_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Lopez D, Sharma A, Murugesan V. Deep Learning Model to predict the outbreak of Dengue in Tamil Nadu based on human mobility. Int J Infect Dis 2020. [DOI: 10.1016/j.ijid.2020.09.948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Gopalakrishnan N, Rajasekar D, Dhanapriya J, Dineshkumar T, Sakthirajan R, Balasubramaniyan T, Murugesan V. Unusual cause of crystalline nephropathy. Saudi J Kidney Dis Transpl 2019; 29:462-465. [PMID: 29657221 DOI: 10.4103/1319-2442.229280] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Adenine phosphoribosyltransferase deficiency is a rare, inherited autosomal recessive disease presenting with 2,8-dihydroxyadenine (DHA) urolithiasis, DHA nephropathy, and chronic kidney disease. The presence of DHA crystals in urine and renal biopsy is pathognomonic of the disease. We report a 23-year-old female with acute renal failure and nephrotic proteinuria. Urinalysis showed reddish brown, round crystals with dark outline, and central spicules consistent with 2,8-DHA crystals. Renal biopsy showed membranous nephropathy and 2,8-DHA nephropathy. Our patient improved with liberal fluid intake, restriction of high adenine content foods, and oral xanthine dehydrogenase inhibitor febuxostat. Early diagnosis and initiation of treatment prevent renal complications.
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Affiliation(s)
- Natarajan Gopalakrishnan
- Institute of Nephrology, Rajiv Gandhi Government General Hospital, Madras Medical College, Chennai, Tamil Nadu, India
| | - Dhanasekaran Rajasekar
- Institute of Nephrology, Rajiv Gandhi Government General Hospital, Madras Medical College, Chennai, Tamil Nadu, India
| | - Jeyachandran Dhanapriya
- Institute of Nephrology, Rajiv Gandhi Government General Hospital, Madras Medical College, Chennai, Tamil Nadu, India
| | - Thanigachalam Dineshkumar
- Institute of Nephrology, Rajiv Gandhi Government General Hospital, Madras Medical College, Chennai, Tamil Nadu, India
| | - Ramanathan Sakthirajan
- Institute of Nephrology, Rajiv Gandhi Government General Hospital, Madras Medical College, Chennai, Tamil Nadu, India
| | - T Balasubramaniyan
- Institute of Nephrology, Rajiv Gandhi Government General Hospital, Madras Medical College, Chennai, Tamil Nadu, India
| | - V Murugesan
- Institute of Nephrology, Rajiv Gandhi Government General Hospital, Madras Medical College, Chennai, Tamil Nadu, India
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Bueno J, Murugesan V, Karatsu K, Thoen DJ, Baselmans JJA. Ultrasensitive Kilo-Pixel Imaging Array of Photon Noise-Limited Kinetic Inductance Detectors Over an Octave of Bandwidth for THz Astronomy. J Low Temp Phys 2018; 193:96-102. [PMID: 30839749 PMCID: PMC6190645 DOI: 10.1007/s10909-018-1962-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 05/10/2018] [Indexed: 06/09/2023]
Abstract
We present the development of a background-limited kilo-pixel imaging array of ultrawide bandwidth kinetic inductance detectors (KIDs) suitable for space-based THz astronomy applications. The array consists of 989 KIDs, in which the radiation is coupled to each KID via a leaky lens antenna, covering the frequency range between 1.4 and 2.8 THz. The single pixel performance is fully characterised using a representative small array in terms of sensitivity, optical efficiency, beam pattern and frequency response, matching very well its expected performance. The kilo-pixel array is characterised electrically, finding a yield larger than 90% and an averaged noise-equivalent power lower than 3 × 10 - 19 W/Hz 1 / 2 . The interaction between the kilo-pixel array and cosmic rays is studied, with an expected dead time lower than 0.6% when operated in an L2 or a similar far-Earth orbit.
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Affiliation(s)
- J. Bueno
- SRON Netherlands Institute for Space Research, Utrecht, The Netherlands
| | - V. Murugesan
- SRON Netherlands Institute for Space Research, Utrecht, The Netherlands
| | - K. Karatsu
- Terahertz Sensing Group, Delft University of Technology, Delft, The Netherlands
| | - D. J. Thoen
- Terahertz Sensing Group, Delft University of Technology, Delft, The Netherlands
| | - J. J. A Baselmans
- SRON Netherlands Institute for Space Research, Utrecht, The Netherlands
- Terahertz Sensing Group, Delft University of Technology, Delft, The Netherlands
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Myilsamy M, Mahalakshmi M, Subha N, Murugesan V. Mesoporous Ga-TiO₂: Role of Oxygen Vacancies for the Photocatalytic Degradation Under Visible Light. J Nanosci Nanotechnol 2018; 18:925-935. [PMID: 29448516 DOI: 10.1166/jnn.2018.14207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Gallium doped mesoporous TiO2 with different weight percentages were synthesized by sol-gel method using Pluronic P123 as the structure directing template. The physico-chemical properties of all the synthesized catalysts were determined by XRD, TEM, SEM-EDAX, N2 adsorption-desorption studies, XPS, UV-vis DRS, FT-IR and photoluminescence spectroscopy. 1.0 wt% Ga-TiO2 exhibited the highest photocatalytic efficiency among all the synthesized materials under visible light due to the high surface area, reduced band gap and suppressed electron-hole recombination. Ga3+ ions substitutions for Ti4+ ions in TiO2 lattice created oxygen vacancies in TiO2 lattice, which created a defect energy level below the conduction band of TiO2 and hence the band gap was reduced. The oxygen vacancy defects was playing significant role to improve the adsorption of oxygen molecules, hydroxide ions and cationic rhodamine B (RhB) on TiO2 surface in an aqueous medium. The lifetime of the charge carriers was also enhanced by trapping the photogenerated electrons in oxygen vacancies and transferring them to the adsorbed O2 to produce superoxide anion radicals (O-. 2 ). The photo-induced holes at valence band reduced the adsorbed OH- ions and produced a large number of .OH radicals, which subsequently degraded the RhB. Hence oxygen vacancies created by gallium doping on TiO2 enhanced the photocatalytic efficiency for the degradation of RhB under visible light.
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Affiliation(s)
- M Myilsamy
- Department of Chemistry, SSN College of Engineering, Kalavakkam 603110, Tamilnadu, India
| | - M Mahalakshmi
- Department of Chemistry, SSN College of Engineering, Kalavakkam 603110, Tamilnadu, India
| | - N Subha
- Department of Chemistry, SSN College of Engineering, Kalavakkam 603110, Tamilnadu, India
| | - V Murugesan
- Department of Chemistry, Abdur Rahman University, Chennai 48, Tamilnadu, India
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Subha N, M. M, Myilsamy M, Reddy NL, Shankar M, Neppolian B, Murugesan V. Influence of synthesis conditions on the photocatalytic activity of mesoporous Ni doped SrTiO3/TiO2 heterostructure for H2 production under solar light irradiation. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.03.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Endo A, Yates SJC, Bueno J, Thoen DJ, Murugesan V, Baryshev AM, Klapwijk TM, van der Werf PP, Baselmans JJA. Superconducting Coplanar Waveguide Filters for Submillimeter Wave On-Chip Filterbank Spectrometers. J Low Temp Phys 2016; 184:412-417. [PMID: 27340291 PMCID: PMC4880640 DOI: 10.1007/s10909-016-1579-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 03/02/2016] [Indexed: 06/06/2023]
Abstract
We show the first experimental results which prove that superconducting NbTiN coplanar-waveguide resonators can achieve a loaded Q factor in excess of 800 in the 350 GHz band. These resonators can be used as narrow band pass filters for on-chip filter bank spectrometers for astronomy. Moreover, the low-loss coplanar waveguide technology provides an interesting alternative to microstrip lines for constructing large scale submillimeter wave electronics in general.
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Affiliation(s)
- A. Endo
- />Department of Microelectronics, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
- />Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - S. J. C. Yates
- />SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen, The Netherlands
| | - J. Bueno
- />SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
| | - D. J. Thoen
- />Department of Microelectronics, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
| | - V. Murugesan
- />SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
| | - A. M. Baryshev
- />SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen, The Netherlands
- />Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen, The Netherlands
| | - T. M. Klapwijk
- />Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
- />Physics Department, Moscow State Pedagogical University, 119991 Moscow, Russia
| | - P. P. van der Werf
- />Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
| | - J. J. A. Baselmans
- />Department of Microelectronics, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
- />SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
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Murugesan V, Pulimamidi VK, Rajappa M, Satheesh S, Revathy G, Harichandrakumari KT. Elevated fibrinogen and lowered homocysteine-vitamin determinants and their association with left atrial thrombus in patients with rheumatic mitral stenosis. Br J Biomed Sci 2015; 72:102-6. [PMID: 26510264 DOI: 10.1080/09674845.2015.11666804] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Mitral stenosis (MS) causes stagnation of blood flow, leading to thrombus formation in the left atrium (LA), which may lead to systemic thrombo-embolic complications and stroke. We compared the alterations in echocardiographic and procoagulant parameters in patients with severe rheumatic MS with and without LA thrombus. The study was a cross-sectional study of patients with rheumatic MS, being evaluated for percutaneous mitral commisurotomy. Group 1 patients comprised of patients with rheumatic MS with LA thrombus (n=35) and Group 2 patients had rheumatic MS without LA thrombus (n = 45). Platelet aggregability, fibrinogen, homocysteine, vitamin B12 and folate; mitral valve area (MVA), mean mitral gradient and pulmonary artery pressure (PAP) were assessed in all study subjects. Significant increase in fibrinogen, homocysteine and platelet aggregation and fall in homocysteine-associated determinants were seen in Group 1, as compared with Group 2. Raised fibrinogen, lowered homocysteine-vitamin determinants and lowered mitral valve area were associated independently, with presence of LA thrombus in rheumatic MS. In this study, fibrinogen, vitamin B12 and folate were independently associated with the occurrence of thrombus in patients with rheumatic MS. Hence, our results suggest that increase in procoagulant mechanisms contribute to increased risk of thrombosis in the left atrium in patients with rheumatic MS.
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Myilsamy M, Murugesan V, Mahalakshmi M. The Effect of Synthesis Conditions on Mesoporous Structure and the Photocatalytic Activity of TiO2 Nanoparticles. J Nanosci Nanotechnol 2015; 15:4664-4675. [PMID: 26369095 DOI: 10.1166/jnn.2015.9772] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Mesoporous TiO2 nanoparticles have been synthesized by sol-gel method in different preparation conditions to investigate the effect of triblock copolymer, acetic acid and water on mesoporous structure and the photocatalytic activity. The synthesized photocatalysts were characterized by means of X-ray powder diffraction, Nitrogen adsorption/desorption studies, High resolution transmission electron microscopy, Scanning electron microscopy, Diffuse reflectance UV-Vis spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and thermogravimetric analysis. Among the various synthesized materials, mesoporous TiO2 synthesized using triblock copolymer as a structure directing template in acetic acid medium with high water ratio calcined at 400 degrees C was found to have the highest photocatalytic activity due to the enhanced band gap energy, high specific surface area and high average pore size. The large mesopores provide more pathways for the reactants to enter and products to escape and enhances the adsorption of methylene blue. The photocatalytic activity decreases with increase of solution pH. The rate of *OH formation is high at lower pH, which enhances the photocatalytic activity was revealed by photoluminescence technique. In addition, the adsorbed hydroxyl groups on the surface of mesoporous TiO2 particles can interact with photogenerated holes to produce more *OH radicals, which enhances charge transfer efficiency and enhances the rate of *OH formation.
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Devika S, Sundaravel B, Palanichamy M, Murugesan V. Vapour phase oxidation of toluene over CeAlPO-5 molecular sieves. J Nanosci Nanotechnol 2014; 14:3187-3192. [PMID: 24734753 DOI: 10.1166/jnn.2014.8571] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Single-site CeAlPO-5 with Al/Ce ratios 25, 50, 75, 100 and 125 were synthesized hydrothermally in fluoride medium. The XRD patterns of CeAlPO-5 exhibited characteristic reflections of AlPO-5. 27Al MAS-NMR of CeAIPO-5(25) showed two unusual peaks at -20.78 and -71.35 ppm due to delocalization of cerium unpaired electron. However, 31P MAS-NMR exhibited the usual characteristic peak similar to that of AlPO-5. Vapour phase oxidation of toluene in air over CeAlPO-5 yielded benzaldehyde with high toluene conversion. The time on stream study established the stability of the catalyst. This catalyst can also be used for the selective oxidation of other alkyl aromatics.
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Selvakumar E, Anandha babu G, Ramasamy P, Murugesan V, Chandramohan A. Synthesis, growth and spectroscopic investigation of an organic molecular charge transfer crystal: 8-hydroxy quinolinium 4-nitrobenzoate 4-nitrobenzoic acid. Spectrochim Acta A Mol Biomol Spectrosc 2014; 117:259-263. [PMID: 23995602 DOI: 10.1016/j.saa.2013.07.097] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 07/22/2013] [Accepted: 07/31/2013] [Indexed: 06/02/2023]
Abstract
An organic intermolecular charge transfer complex salt of 8-Hydroxy quinolinium 4-nitrobenzoate 4-nitrobenzoic acid (OPNB) has been synthesized. Single crystals of OPNB were grown by slow solvent evaporation solution growth technique at room temperature. The (1)H and (13)C NMR spectra were recorded to confirm the molecular structure of the complex salt. The crystal structure of OPNB has been determined by single crystal XRD analysis and it belongs to triclinic crystal system with space group P-1. Fourier transform infrared (FT-IR) spectral study has been carried out to identify the various functional groups present. The UV-Vis-NIR transmittance spectrum was recorded in the range 200-2500nm, to find the suitability of the single crystal for various optical applications. The thermal stability of the crystal was investigated using thermogravimetric (TG) and differential thermal analyses (DTA).
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Affiliation(s)
- E Selvakumar
- Postgraduate and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641 020, Tamilnadu, India
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Rawal RK, Murugesan V, Katti SB. Structure-activity relationship studies on clinically relevant HIV-1 NNRTIs. Curr Med Chem 2013; 19:5364-80. [PMID: 22998569 DOI: 10.2174/092986712803833326] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 08/25/2012] [Accepted: 08/29/2012] [Indexed: 11/22/2022]
Abstract
In addition to the nucleoside reverse transcriptase inhibitors (NRTIs), protease inhibitors (PIs) and integrase inhibitors (INIs), nonnucleoside reverse transcriptase inhibitors (NNRTIs) have contributed significantly in the treatment of HIV-1 infections. More than 60 structurally different classes of compounds have been identified as NNRTIs, which are specifically inhibiting HIV-1 reverse transcriptase (RT). Five NNRTIs (nevirapine, delavirdine, efavirenz, etravirine and rilpivirine) have been approved by US Food and Drug Administration (FDA) for clinical use. The NNRTIs bind with a specific 'pocket' site of HIV-1 RT (allosteric site) that is closely associated with the NRTI binding site. Due to mutations of the amino acid residues surrounding the NNRTI-binding site, NNRTIs are notorious for rapidly eliciting resistance. Though, the emergence of resistant HIV strains can be circumvented if the NNRTIs are used either alone or in combination with NRTIs (AZT, 3TC, ddI, ddC, TVD or d4T) and PIs (Indinavir, nelfinavir, saquinavir, ritonavir and lopinavir etc.) as shown by both a decrease in plasma HIV-1 RNA levels and increased CD4 T-cells. Here we are going to discuss recent advances in structure activity relationship studies on nevirapine, delavirdine, efavirenz, etravirine, rilpivirine and 4-thiazolidinones (privileged scaffold) HIV-1 NNRTIs.
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Affiliation(s)
- R K Rawal
- Medicinal and Process Chemistry Division, Central Drug Research Institute, Lucknow 226001, India
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Palanisamy B, Babu CM, Sundaravel B, Anandan S, Murugesan V. Sol-gel synthesis of mesoporous mixed Fe2O3/TiO2 photocatalyst: application for degradation of 4-chlorophenol. J Hazard Mater 2013; 252-253:233-42. [PMID: 23535564 DOI: 10.1016/j.jhazmat.2013.02.060] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 02/10/2013] [Accepted: 02/28/2013] [Indexed: 05/06/2023]
Abstract
Photosensitization of TiO2 with other transition metal oxides can extend its light absorption property in the visible region. Such materials could emerge as excellent catalysts for solar photocatalytic degradation. In the present study mesoporous Fe2O3/TiO2 (10, 30, 50, 70 and 90 wt% Fe2O3) photocatalysts were synthesized by sol-gel process and characterized using different techniques. The XRD patterns exhibited the presence of mesoporous structure and isomorphic substitution of Fe(3+) in TiO2 at low Fe(3+) loading and Ti(4+) in Fe2O3 at high Fe(3+) loading. The XPS results revealed the presence of Ti(4+) and Fe(3+) in Fe2O3/TiO2 materials. The DRS UV-vis spectra showed a shift in the band gap excitation of TiO2 to longer wavelength, thus illustrating incorporation of Fe(3+) in TiO2. In addition, free TiO2 and Fe2O3 particles were also present. Their photocatalytic activity was tested for the degradation of 4-chlorophenol in aqueous medium using sunlight. The activity of the catalysts followed the order: meso-30 wt% Fe2O3/TiO2>meso-10 wt% Fe2O3/TiO2>meso-50 wt% Fe2O3/TiO2>meso-70 Fe2O3/TiO2>meso-90 wt% Fe2O3/TiO2>meso-Fe2O3>meso-TiO2. This order concluded that mesoporous Fe2O3/TiO2 could be an active catalyst for pollutant degradation, as TiO2 with framework Fe(3+) and photosensitization with free Fe2O3 were involved in the activity.
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Affiliation(s)
- B Palanisamy
- Department of Chemistry, Anna University, Chennai 600 025, India
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Palanisamy B, Babu CM, Sundaravel B, Anandan S, Murugesan V. Visible-light active mesoporous ce incorporated TiO2 for the degradation of 4-chlorophenol in aqueous solution. J Nanosci Nanotechnol 2013; 13:2573-2581. [PMID: 23763131 DOI: 10.1166/jnn.2013.7404] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Efficient visible-light active mesoporous Ce incorporated TiO2 nanoparticles have been prepared by sol-gel method using Pluranic P123 as the structure directing agent. Low angle XRD and BET analysis revealed the mesoporous nature of the nanoparticles. The incorporation of Ce4+ into TiO2 and Ti4+ into CeO2 is evident from the slight shift in their respective XRD patterns. XPS results exhibited +4 oxidation state for Ce and Ti ions. UV-DRS analysis of Ce incorporated TiO2 demonstrated red shift in the absorbance spectrum of TiO2, which is mainly due to the formation of Ce impurity states below the conduction band edge of TiO2. The photocatalytic activity of mesoporous Ce incorporated TiO2 nanoparticles has been evaluated in the degradation of 4-chlorophenol in aqueous solution under solar light illumination. Pure mesoporous TiO2 showed poor visible-light activity due to its small absorption of sun light. Mesoporous Ce incorporated TiO2 photocatalysts exhibited the highest photocatalytic activity compared to pristine mesoporous TiO2 and CeO2. The incorporation of Ce4+ in TiO2 played a major role in the enhancement of photocatalytic activity under sun light.
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Affiliation(s)
- B Palanisamy
- Department of Chemistry, Anna University, Chennai 600025, India
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Sundaravel B, Babu CM, Palanisamy B, Palanichamy M, Shanthi K, Murugesan V. Praseodymium incorporated AIPO-5 molecular sieves for aerobic oxidation of ethylbenzene. J Nanosci Nanotechnol 2013; 13:2507-2516. [PMID: 23763124 DOI: 10.1166/jnn.2013.7415] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PrAlPO-5 with (Al + P)/Pr ratios of 25, 50, 75 and 100 molecular sieves were successfully synthesized by hydrothermal method. These molecular sieves were characterised using XPS, TPD-NH3, ex-situ pyridine adsorbed IR, TPR, TGA, 27Al and 31P MAS-NMR and ESR studies. The incorporation of praseodymium in the framework of AlPO-5 was confirmed by XRD, DRS UV-vis and 27Al and 31P MAS-NMR analysis. ESR spectrum showed the presence of adsorbed oxygen. The nature and strength of acid sites were identified by ex-situ pyridine adsorbed IR and TPD-NH3. The BET surface area was found to be in the range of 238-272 m2 g(-1). The catalytic activity of the molecular sieves was tested for the liquid phase aerobic oxidation of ethylbenzene. Acetophenone was found to be the major product with more than 90% ethylbenzene conversion. ICP-OES analysis revealed the presence of praseodymium intact in the framework of AlPO-5 up to five cycles.
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Affiliation(s)
- B Sundaravel
- Department of Chemistry, Anna University, Chennai 600025, India
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Visuvamithiran P, Sundaravel B, Palanichamy M, Murugesan V. Oxidation of alkyl aromatics over SBA-15 supported cobalt oxide. J Nanosci Nanotechnol 2013; 13:2528-2537. [PMID: 23763126 DOI: 10.1166/jnn.2013.7388] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
SBA-15 supported Co3O4 with different weight percentage have been prepared by wet impregnation method. The prepared catalysts were characterised by XRD, DRUV-vis, FT-IR, N2 adsorption-desorption, TPR, XPS, SEM and TEM. The TPR profile revealed good dispersion of active sites and interaction of Co3O4 on SBA-15 support. The catalytic activity of SBA-15 supported Co3O4 was evolved in liquid phase benzylic oxidation under mild condition using H2O2 as the oxidant. The benzylic oxidation was ascribed by hydrogen abstraction of the C-H bond. The various reaction parameters such as Co3O4 loading, solvent, temperature and reaction time on the catalytic activity were also investigated. The 5 wt% of Co3O4/SBA-15 catalyst was found to exhibit high conversion (-75%) with product selectivity of -87%.
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Babu CM, Palanisamy B, Sundaravel B, Palanichamy M, Murugesan V. A novel magnetic Fe3O4/SiO2 core-shell nanorods for the removal of arsenic. J Nanosci Nanotechnol 2013; 13:2517-2527. [PMID: 23763125 DOI: 10.1166/jnn.2013.7376] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A novel magnetic Fe3O4 core-shell nanorods (MCSNs) were synthesized by crosslinking amine functionalized Fe3O4@SiO2 core-shell nanoparticles with 1,2-bromochloroethane. These nanorods were then protonated with dilute HCl. The MCSNs nanorods were characterized using FT-IR, N2 adsorption, VSM, SEM and TEM. The surface area of MCSNs nanorods was found to be 335 m2/g, which is higher than bare iron oxide and amine functionalized Fe3O4@SiO2. These nanorods were used simultaneously as ion-exchanger and adsorbent for the removal of arsenic from aqueous solution. It exhibited high adsorption capacity for arsenic. The kinetic study revealed that adsorption equilibrium attained within five min. The adsorbed arsenic on the nanorods were removed by magnetic separation and regenerated by acid treatment. The percentage removal of arsenic was more than 99%. Such nanorods can be used to remove not only arsenic but also other anions from potable water.
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Affiliation(s)
- C M Babu
- Department of Chemistry, Anna University, Chennai 600025, India
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Visuvamithiran P, Shanthi K, Palanichamy M, Murugesan V. Direct synthesis of Mn-Ti-SBA-15 catalyst for the oxidation of ethylbenzene. Catal Sci Technol 2013. [DOI: 10.1039/c3cy00306j] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kumaresan L, Prabhu A, Palanichamy M, Arumugam E, Murugesan V. Synthesis and characterization of Zr4+, La3+ and Ce3+ doped mesoporous TiO2: evaluation of their photocatalytic activity. J Hazard Mater 2011; 186:1183-1192. [PMID: 21237564 DOI: 10.1016/j.jhazmat.2010.11.124] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 11/28/2010] [Accepted: 11/29/2010] [Indexed: 05/30/2023]
Abstract
Sol-gel method was used to synthesize Zr(4+), La(3+) and Ce(3+) doped mesoporous TiO(2) materials with different weight percentage (0.5, 1.0, 2.0 and 3.0 wt%) using triblock copolymer as the structure directing template in ethanol/water medium. Characterization revealed the isomorphic substitution of Zr(4+) ion into the lattice of TiO(2), and surface binding nature of La(3+) and Ce(3+) ions on mesoporous TiO(2). Microscopic examination confirmed the surface adsorption of foreign ion which could alter the particle morphology. The size of the particles was less than 20 nm. Photocatalytic activity of metal ions doped mesoporous TiO(2) was evaluated using aqueous alachlor as a model pollutant. It was found that 1 wt% Ce(3+) doped mesoporous TiO(2) exhibited higher activity than pure and other metal ions doped mesoporous TiO(2). The change of oxidation state of Ce(3+) is suggested to be the cause for enhanced photocatalytic activity.
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Affiliation(s)
- L Kumaresan
- Department of Chemistry, Anna University, Chennai 600 025, India
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Sivamurugan V, Deepa K, Palanichamy M, Murugesan V. [(L)Proline]2Zn Catalysed Synthesis of 1,5‐Benzodiazepine Derivatives Under Solvent‐Free Condition. SYNTHETIC COMMUN 2011. [DOI: 10.1081/scc-200034752] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- V. Sivamurugan
- a Department of Chemistry , Anna University , Chennai, 600 025, India
| | - K. Deepa
- a Department of Chemistry , Anna University , Chennai, 600 025, India
| | - M. Palanichamy
- a Department of Chemistry , Anna University , Chennai, 600 025, India
| | - V. Murugesan
- a Department of Chemistry , Anna University , Chennai, 600 025, India
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Kumaresan L, Mahalakshmi M, Palanichamy M, Murugesan V. Synthesis, Characterization, and Photocatalytic Activity of Sr2+ Doped TiO2 Nanoplates. Ind Eng Chem Res 2010. [DOI: 10.1021/ie901191z] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- L. Kumaresan
- Department of Chemistry, Anna University, Chennai 600 025, India, and Department of Chemistry, SSN College of Engineering, Kalavakkam 603 110, India
| | - M. Mahalakshmi
- Department of Chemistry, Anna University, Chennai 600 025, India, and Department of Chemistry, SSN College of Engineering, Kalavakkam 603 110, India
| | - M. Palanichamy
- Department of Chemistry, Anna University, Chennai 600 025, India, and Department of Chemistry, SSN College of Engineering, Kalavakkam 603 110, India
| | - V. Murugesan
- Department of Chemistry, Anna University, Chennai 600 025, India, and Department of Chemistry, SSN College of Engineering, Kalavakkam 603 110, India
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Anandan S, Kathiravan K, Murugesan V, Ikuma Y. Anionic (IO3-) non-metal doped TiO2 nanoparticles for the photocatalytic degradation of hazardous pollutant in water. CATAL COMMUN 2009. [DOI: 10.1016/j.catcom.2008.12.054] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Mahalakshmi M, Vishnu Priya S, Arabindoo B, Palanichamy M, Murugesan V. Photocatalytic degradation of aqueous propoxur solution using TiO2 and Hbeta zeolite-supported TiO2. J Hazard Mater 2009; 161:336-343. [PMID: 18455297 DOI: 10.1016/j.jhazmat.2008.03.098] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Revised: 03/21/2008] [Accepted: 03/24/2008] [Indexed: 05/26/2023]
Abstract
Photocatalytic activity of TiO2 and zeolites supported TiO2 were investigated using propoxur as a model pollutant. Hbeta, HY and H-ZSM-5 zeolites were examined as supports for TiO2. Hbeta was chosen as the TiO2 support based on the adsorption capacity of propoxur on these zeolites (Hbeta>HY=H-ZSM-5). TiO2/Hbeta photocatalysts with different wt.% were prepared and characterized by XRD, FT-IR and BET surface area. The progress of photocatalytic degradation of aqueous propoxur solution using TiO2 (Degussa P-25) and TiO2 supported on Hbeta zeolite was monitored using TOC analyzer, HPLC and UV-vis spectrophotometer. The degradation of propoxur was systematically studied by varying the experimental parameters in order to achieve maximum degradation efficiency. The initial rate of degradation with TiO2/Hbeta was higher than with bare TiO2. TOC results revealed that TiO2 requires 600min for complete mineralization of propoxur whereas TiO2/Hbeta requires only 480min. TiO2/Hbeta showed enhanced photodegradation due to its high adsorption capacity on which the pollutant molecules are pooled closely and hence degraded effectively.
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Affiliation(s)
- M Mahalakshmi
- Department of Chemistry, Anna University, Chennai 600025, India
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Anandan S, Vinu A, Mori T, Gokulakrishnan N, Srinivasu P, Murugesan V, Ariga K. Erratum to “Photocatalytic degradation of 2,4,6-trichlorophenol using lanthanum doped ZnO in aqueous suspension” [Catalysis Communications 8 (9) (2007) 1377–1382]. CATAL COMMUN 2008. [DOI: 10.1016/j.catcom.2008.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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35
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Sudha S, Venkatachalam K, Vishnu Priya S, Herbert Mabel J, Palanichamy M, Murugesan V. Single step synthesis of coumarin derivatives over Al-MCM-41 and its supported catalysts under solvent-free condition. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.molcata.2008.04.021] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Affiliation(s)
| | | | - V. Murugesan
- a Department of Chemistry , Anna University , Chennai , 600 025 , INDIA
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Mahalakshmi M, Arabindoo B, Palanichamy M, Murugesan V. Preparation, characterization, and photocatalytic activity of Gd3+ doped TiO2 nanoparticles. J Nanosci Nanotechnol 2007; 7:3277-3285. [PMID: 18019161 DOI: 10.1166/jnn.2007.689] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
TiO2 and Gd3+ doped TiO2 nanoparticles were prepared by sol-gel method and the materials were characterized by XRD, TEM, SEM-EDX, BET, FT-IR, UV-Vis absorption, and Raman spectral analysis. The photocatalytic activity of nano TiO2 and Gd/TiO2 nanoparticles was evaluated using a model pollutant propoxur, a carbamate pesticide, in a batch type UV photoreactor. The results revealed higher photocatalytic activity for Gd/TiO2 nanoparticles than both TiO2 nanoparticles and commercial TiO2 (Degussa P-25). The enhanced photocatalytic activity of Gd/TiO2 relative to TiO2 is attributed to its increased band gap energy as evidenced from the blue shift to shorter wavelength observed in the UV-Vis abso4ption spectra. The recombination rate of photogenerated electron-hole pair decreased due to increase in the band gap, which enhanced the charge transfer efficiency of Gd/TiO2 nanoparticles. Gd3+ with its half filled 7 f subshell facilitated rapid electron transfer at solid-liquid interface by shallowly trapping the electrons. Among the various dopant level of gadolinium, 0.3 wt% Gd/TiO2 nanoparticles showed higher activity than others due to its higher surface area.
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Affiliation(s)
- M Mahalakshmi
- Department of Chemistry, Anna University, Chennai 600025, India
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Mahalakshmi M, Arabindoo B, Palanichamy M, Murugesan V. Photocatalytic degradation of carbofuran using semiconductor oxides. J Hazard Mater 2007; 143:240-5. [PMID: 17045739 DOI: 10.1016/j.jhazmat.2006.09.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 07/02/2006] [Accepted: 09/06/2006] [Indexed: 05/12/2023]
Abstract
The photocatalytic degradation of carbofuran (2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate) was investigated in an aqueous solution using Degussa P-25 TiO2 and ZnO as photocatalysts. The progress of degradation was monitored using TOC analyzer, HPLC, GC-MS and UV-vis spectrophotometer. The effects of various experimental parameters such as initial concentration of carbofuran, pH of the solution, catalyst loading and light intensity were systematically studied in order to achieve maximum degradation efficiency. The complete mineralization of carbofuran was confirmed by TOC analyzer. The degradation with ZnO showed less efficiency than TiO2. The formation of NO(3)(-) was identified and quantified using HPLC. In addition, four different intermediates formed during the degradation process were also identified and characterized by GC-MS. The mineralization rate was compared with lamps of wavelength 254 and 365 nm under similar conditions. The rate with 254 nm was observed to be very close to that of 365 nm.
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Affiliation(s)
- M Mahalakshmi
- Department of Chemistry, Anna University, Chennai 600 025, India
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40
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Venkatachalam N, Palanichamy M, Arabindoo B, Murugesan V. Enhanced photocatalytic degradation of 4-chlorophenol by Zr4+ doped nano TiO2. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.molcata.2006.10.051] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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41
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Kumar GS, Vishnuvarthan M, Palanichamy M, Murugesan V. SBA-15 supported HPW: Effective catalytic performance in the alkylation of phenol. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.molcata.2006.07.050] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Venkatachalam N, Vinu A, Anandan S, Arabindoo B, Murugesan V. Visible light active photocatalytic degradation of bisphenol-A using nitrogen doped TiO2. J Nanosci Nanotechnol 2006; 6:2499-507. [PMID: 17037863 DOI: 10.1166/jnn.2006.531] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Nitrogen doped titania was prepared by low temperature sol-gel method using titanium precursor and nitrogen containing bases like triethylamine and tetramethyl ammonium hydroxide compounds. The materials were characterized by XRD, BET, SEM, XPS, DRS-UV, and FT-IR techniques. DRS-UV study substantially indicates shift of the absorption edge of TiO2 to lower energy region. The phase composition, crystallinity, specific surface area, and visible light activity of nitrogen doped titania depend upon the preparation conditions. Photocatalytic degradation of bisphenol-A in aqueous medium was investigated by TiO2 and nitrogen doped TiO2 under visible light irradiation in a batch photocatalytic reactor. The results indicate higher visible light activity for nitrogen doped TiO2 than commercial TiO2 (Degussa P25) for bisphenol-A degradation. The influence of various parameters such as initial concentration of bisphenol-A, catalyst loading and pH was examined for maximum degradation efficiency.
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Affiliation(s)
- N Venkatachalam
- Department of Chemistry, Anna University, Chennai 600 025, India
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44
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Shankar MV, Anandan S, Venkatachalam N, Arabindoo B, Murugesan V. Fine route for an efficient removal of 2,4-dichlorophenoxyacetic acid (2,4-D) by zeolite-supported TiO2. Chemosphere 2006; 63:1014-21. [PMID: 16289243 DOI: 10.1016/j.chemosphere.2005.08.041] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Revised: 08/16/2005] [Accepted: 08/23/2005] [Indexed: 05/05/2023]
Abstract
Zeolites HY, Hbeta and HZSM-5 with different physico-chemical properties were chosen as support for TiO2 to illustrate their adsorption, dispersion and electronic structure in photocatalysis. The extent of TiO2 loading was monitored by XRD and BET surface area measurements. The adsorption capacity of HY zeolite was found to be high and hence chosen for further modification to continue the investigation. Photodegradation kinetics were carried out with 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution. The extent of 2,4-D degradation on TiO2/HY loading revealed the importance of adsorption in photocatalysis. Mineralisation studies on all three zeolites with 1 wt.% TiO2 loading demonstrated the good dispersion properties of TiO2/HY. Its photocatalytic activity was found to be excellent with formulated 2,4-D. Comparison of relative photonic efficiencies demonstrated that supported photocatalysts exhibited higher activity than some of the commercial photocatalysts. The high activity of supported TiO2 is due to synergistic effects of improved adsorption of 2,4-D and efficient delocalisation of photogenerated electrons by zeolite support.
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Affiliation(s)
- M V Shankar
- Department of Chemistry, Anna University, Chennai, Tamil Nadu 600 025, India
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Sivamurugan V, Vinu A, Palanichamy M, Murugesan V. Rapid and cleaner synthesis of 1,4-dihydropyridines in aqueous medium. Heteroatom Chem 2006. [DOI: 10.1002/hc.20197] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Krithiga T, Vinu A, Ariga K, Arabindoo B, Palanichamy M, Murugesan V. Selective formation 2,6-diisopropyl naphthalene over mesoporous Al-MCM-48 catalysts. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.molcata.2005.05.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Vinu A, Satish Kumar G, Ariga K, Murugesan V. Preparation of highly ordered mesoporous AlSBA-15 and its application to isopropylation of m-cresol. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.molcata.2005.03.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sivamurugan V, Kumar RS, Palanichamy M, Murugesan V. Synthesis of hantzsch 1,4-dihydropyridines under solvent-free condition using zn[(L)proline]2as lewis acid catalyst. J Heterocycl Chem 2005. [DOI: 10.1002/jhet.5570420534] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Shankar M, Cheralathan K, Arabindoo B, Palanichamy M, Murugesan V. Enhanced photocatalytic activity for the destruction of monocrotophos pesticide by TiO2/Hβ. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.molcata.2004.03.059] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Nandhini KU, Arabindoo B, Palanichamy M, Murugesan V. t-Butylation of phenol over mesoporous aluminophosphate and heteropolyacid supported aluminophosphate molecular sieves. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.molcata.2004.03.060] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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