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Ashokkumar P, Kabilan R, Sathish Aravindh M, Venkatesan A, Lakshmanan M. Harnessing vibrational resonance to identify and enhance input signals. Chaos 2024; 34:013129. [PMID: 38252785 DOI: 10.1063/5.0169195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 12/21/2023] [Indexed: 01/24/2024]
Abstract
We report the occurrence of vibrational resonance and the underlying mechanism in a simple piecewise linear electronic circuit, namely, the Murali-Lakshmanan-Chua circuit, driven by an additional biharmonic signal with widely different frequencies. When the amplitude of the high-frequency force is tuned, the resultant vibrational resonance is used to detect the low-frequency signal and also to enhance it into a high-frequency signal. Further, we also show that even when the low-frequency signal is changed from sine wave to square and sawtooth waves, vibrational resonance can be used to detect and enhance them into high-frequency signals. These behaviors, confirmed by experimental results, are illustrated with appropriate analytical and numerical solutions of the corresponding circuit equations describing the system. Finally, we also verify the signal detection in the above circuit even with the addition of noise.
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Affiliation(s)
- P Ashokkumar
- PG & Research Department of Physics, Nehru Memorial College (Autonomous), Affiliated to Bharathidasan University, Puthanampatti, Tiruchirappalli 621 007, India
- Department of Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620 024, India
| | - R Kabilan
- PG & Research Department of Physics, Nehru Memorial College (Autonomous), Affiliated to Bharathidasan University, Puthanampatti, Tiruchirappalli 621 007, India
| | - M Sathish Aravindh
- Department of Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620 024, India
| | - A Venkatesan
- PG & Research Department of Physics, Nehru Memorial College (Autonomous), Affiliated to Bharathidasan University, Puthanampatti, Tiruchirappalli 621 007, India
| | - M Lakshmanan
- Department of Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620 024, India
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Venkatesan A, Chouhan U, Suryawanshi SK, Choudhari JK. An in silico approach for prediction of B cell and T cell epitope candidates against Chikungunya virus. Immunol Med 2023; 46:163-174. [PMID: 37078425 DOI: 10.1080/25785826.2023.2202038] [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: 11/11/2022] [Accepted: 04/08/2023] [Indexed: 04/21/2023] Open
Abstract
Several outbreaks of Chikungunya virus (CHIKV) had been reported since 1952 when mankind had his first encounter against the virus in Tanzania. Although these reports designate the CHIKV to be rarely fatal, cases of outbreaks in the last decade accompanied by severe complications and death poses a challenge to the development of effective treatment methods. Several attempts to vaccine development against CHIKV still remains unsuccessful. In this study, we aimed at the prediction of B-cell and T cell epitopes against CHIKV by using immunoinformatics. This, in turn, can contribute to development of an epitope based vaccine against CHIKV. Both linear and discontinuous B-cell epitopes, as well as Cytotoxic T-lymphocyte epitopes, were predicted for the CHIKV Envelope (E1 and E2) glycoproteins and (NS2). The antigenic CTL epitopes with highest binding affinities with type-1 MHC were selected and the peptides were docked to them. Docking followed by molecular dynamics simulations were performed to assess the stability of the docked complexes.
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Affiliation(s)
- Amrit Venkatesan
- Department of Mathematics, Bioinformatics & Computer Applications, Maulana Azad National Institute of Technology, Bhopal, Madhya Pradesh, India
| | - Usha Chouhan
- Department of Mathematics, Bioinformatics & Computer Applications, Maulana Azad National Institute of Technology, Bhopal, Madhya Pradesh, India
| | - Sunil Kumar Suryawanshi
- Department of Mathematics, Bioinformatics & Computer Applications, Maulana Azad National Institute of Technology, Bhopal, Madhya Pradesh, India
| | - Jyoti Kant Choudhari
- Department of Mathematics, Bioinformatics & Computer Applications, Maulana Azad National Institute of Technology, Bhopal, Madhya Pradesh, India
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Seo A, Xiao W, Gjyshi O, Court K, Napravnik TC, Venkatesan A, Lynn EJ, Sammouri J, Colbert L, Jhingran A, Joyner MM, Lin LL, Gillison M, Klopp AH. HPV Circulating Cell-Free DNA Kinetics in Cervical Cancer Patients Undergoing Definitive Chemoradiation. Int J Radiat Oncol Biol Phys 2023; 117:S8-S9. [PMID: 37784579 DOI: 10.1016/j.ijrobp.2023.06.218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) The human papilloma virus (HPV) is a significant cause of cervical cancer and viral DNA can be detected in the blood of patients with cervical cancer (cfHPV-DNA). We hypothesized that detecting HPV cfDNA before, during and after chemoradiation (CRT) could provide insights into disease extent, clinical staging, and treatment response. MATERIALS/METHODS Forty-seven patients with cervical cancer were enrolled on this study between 2017 and 2022, either as part of a standard-of-care (SOC) treatment banking protocol (33 patients) or as part of a clinical trial combining a therapeutic HPV vaccine (PDS0101; Immunocerv, 14 patients). Longitudinal plasma samples were collected from each patient as baseline, during week 1, 3 or 5 of CRT. cfHPV-DNA was quantified using droplet digital PCR targeting the HPV E6/E7 oncogenes of 13 high-risk types based on analysis of cervical tumor genotype (AmpFire). Clinical covariates, including FIGO stage, primary tumor size, and treatment response were studied using appropriate statistical tests. RESULTS All 47 patients had detectable HPV cfDNA during CRT with 38 out of 47 having HPV type 16 detected. The median cfDNA at baseline was 24.5 copies/mL, with a range of 0 to 157,638 copies/mL. Of the 35 patients with at least three measurements, 20 (57%) had peak cfDNA counts at week 3, and 30 out of 35 showed a decline in cfDNA counts at week 5 compared to week 3. The proportion of patients who cleared cfDNA (<16 copies/mL) increased with each week of CRT, reaching 75% at week 5. Baseline cfDNA counts were associated with para-aortic nodal involvement (p<0.0001) but not with FIGO stage or gross tumor volume. A greater proportion of patients treated with therapeutic HPV-directed vaccine had clearance of cfDNA counts as compared to those treated with SOC (at week 3, 38% vs 5%, P = 0.02 and week 5, 79% vs 22%, P = 0.0054) CONCLUSION: HPV cfDNA levels change dynamically throughout definitive CRT and peak during the first 3 weeks for the majority of patients. Treatment with a therapeutic HPV vaccine was associated with a more rapid decline in cfHPV DNA. Further analysis of cfDNA kinetics could provide valuable information on the relationship between cfDNA levels, treatment response, and clinical outcomes.
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Affiliation(s)
- A Seo
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - W Xiao
- The University of Texas MD Anderson Cancer Center, Houston, TX
| | - O Gjyshi
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - K Court
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - T Cisneros Napravnik
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - A Venkatesan
- Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - E J Lynn
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - J Sammouri
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - L Colbert
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - A Jhingran
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - M M Joyner
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - L L Lin
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - M Gillison
- The University of Texas MD Anderson Cancer Center, Houston, TX
| | - A H Klopp
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
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Devi VK, Venkatesan A, Bharathi AN, Parvathy G, Kaliammal R, Kumar MK, Sudhahar S. Third Order Nonlinear Optical Properties of Bis (Creatininium 2,4-Dichlorobenzoate) Monohydrate Organic New Single Crystal. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2022.134115] [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]
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Venkatesan A, Al-Onazi WA, Elshikh MS, Pham TH, Suganya S, Boobas S, Priyadharsan A. Study of synergistic effect of cobalt and carbon codoped with TiO 2 photocatalyst for visible light induced degradation of phenol. Chemosphere 2022; 305:135333. [PMID: 35709834 DOI: 10.1016/j.chemosphere.2022.135333] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/30/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
In this work, we reported synthesis of cobalt and carbon codoped TiO2 (Co-C-TiO2) nanoparticles were prepared using co-precipitation technique. The synthesized catalysts are analyzed by various methods. The powder XRD pattern confirmed that all the samples were polycrystalline of anatase phase and particle size of resultant nanoparticle was reduced correlated with bare TiO2 sample. FTIR measurements exhibit the identification of functional groups present at the surface of TiO2. FESEM micrograph showed that the shape of codoped TiO2 nanoparticles are approximately sphere. The attained energy gap of Co doped and C codoping of TiO2 modifies to a level below the energy gap of TiO2 anatase specifying a high capability to absorb visible light. The recombination rate of photo-induced electrons and holes for Co-C codoped TiO2 nanoparticles is significantly reduced. The synthesized samples are assessed in degradation of phenol by the illumination of visible light. The results confirmed that photocatalytic activity enhanced due to doping and codoping of Co and C. As a result, Co-C codoped TiO2 nanoparticles exhibited a higher visible-light photocatalytic activity in compared with Co-TiO2 and bare TiO2 with the maximum degradation efficiency of 98, 75 and 15%, respectively. And also, the reusability of the catalyst was proved when 95% degradation could be achieved after consecutive batches. It is predictable that this work will provide new insights to increase the visible light active photocatalysts for environmental problems.
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Affiliation(s)
- A Venkatesan
- Department of Physics, Annai College of Arts and Sciences (Affiliated to Bharthidasan University), Trichy, Kovilacheri, Kumbakonam, 612503, Tamilnadu, India
| | - Wedad A Al-Onazi
- Department of Chemistry, College of Science, King Saud University, P.O. Box 22452, Riyadh, 11495, Saudi Arabia
| | - Mohamed S Elshikh
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Thi Huong Pham
- Department of Materials Science and Engineering, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam, 13120, South Korea
| | - S Suganya
- Department of Physics, NKR Government Arts College for Women, Namakkal, 637001, Tamilnadu, India
| | - S Boobas
- Department of Physics, Sri Vasavi College, Bhavani, 638301, Tamilnadu, India.
| | - A Priyadharsan
- Department of Physics, E.R.K Arts and Science College, Dharmapuri, 636905, Tamilnadu, India.
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Sanders J, Mok H, Tang C, Hanania A, Venkatesan A, Bruno T, Kudchadker R, Thames H, Frank S. Benchmarking Automatic Segmentation Algorithms Against Human Interobserver Variability of Prostate and Organs at Risk Delineation on Prostate MRI. Int J Radiat Oncol Biol Phys 2021. [DOI: 10.1016/j.ijrobp.2021.07.926] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kim J, Venkatesan A, Kim H, Kim Y, Whang D, Kim G. Improved Contact Resistance by a Single Atomic Layer Tunneling Effect in WS 2 /MoTe 2 Heterostructures. Adv Sci (Weinh) 2021; 8:e2100102. [PMID: 34105270 PMCID: PMC8188188 DOI: 10.1002/advs.202100102] [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: 01/12/2021] [Revised: 02/01/2021] [Indexed: 06/12/2023]
Abstract
Manipulation of Ohmic contacts in 2D transition metal dichalcogenides for enhancing the transport properties and enabling its application as a practical device has been a long-sought goal. In this study, n-type tungsten disulfide (WS2 ) single atomic layer to improve the Ohmic contacts of the p-type molybdenum ditelluride (MoTe2 ) material is covered. The Ohmic properties, based on the lowering of Schottky barrier height (SBH) owing to the tunneling barrier effect of the WS2 monolayer, are found to be unexpectedly excellent at room temperature and even at 100 K. The improved SBH and contact resistances are 3 meV and 1 MΩ µm, respectively. The reduction in SBH and contact resistance is confirmed with temperature-dependent transport measurements. This study further demonstrates the selective carrier transport across the MoTe2 and WS2 layers by modulating the applied gate voltage. This WS2 /MoTe2 heterostructure exhibits excellent gate control over the currents of both channels (n-type and p-type). The on/off ratios for both the electron and hole channels are calculated as 107 and 106 , respectively, indicating good carrier type modulation by the electric field of the gate electrode. The Ohmic contact resistance using the tunneling of the atomic layer can be applied to heterojunction combinations of various materials.
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Affiliation(s)
- Jihoon Kim
- School of Electronic and Electrical EngineeringSungkyunkwan University (SKKU)Suwon16419Republic of Korea
| | - A. Venkatesan
- School of Electronic and Electrical EngineeringSungkyunkwan University (SKKU)Suwon16419Republic of Korea
| | - Hanul Kim
- Samsung‐SKKU Graphene CentreSungkyunkwan Advanced Institute of Nanotechnology (SAINT)Sungkyunkwan University (SKKU)Suwon16419Republic of Korea
| | - Yewon Kim
- School of Electronic and Electrical EngineeringSungkyunkwan University (SKKU)Suwon16419Republic of Korea
| | - Dongmok Whang
- Samsung‐SKKU Graphene CentreSungkyunkwan Advanced Institute of Nanotechnology (SAINT)Sungkyunkwan University (SKKU)Suwon16419Republic of Korea
- School of Advanced Materials Science and EngineeringSungkyunkwan University (SKKU)Suwon16419Republic of Korea
| | - Gil‐Ho Kim
- School of Electronic and Electrical EngineeringSungkyunkwan University (SKKU)Suwon16419Republic of Korea
- Samsung‐SKKU Graphene CentreSungkyunkwan Advanced Institute of Nanotechnology (SAINT)Sungkyunkwan University (SKKU)Suwon16419Republic of Korea
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Ashokkumar P, Sathish Aravindh M, Venkatesan A, Lakshmanan M. Realization of all logic gates and memory latch in the SC-CNN cell of the simple nonlinear MLC circuit. Chaos 2021; 31:063119. [PMID: 34241282 DOI: 10.1063/5.0046968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 05/28/2021] [Indexed: 06/13/2023]
Abstract
We investigate the State-Controlled Cellular Neural Network framework of Murali-Lakshmanan-Chua circuit system subjected to two logical signals. By exploiting the attractors generated by this circuit in different regions of phase space, we show that the nonlinear circuit is capable of producing all the logic gates, namely, or, and, nor, nand, Ex-or, and Ex-nor gates, available in digital systems. Further, the circuit system emulates three-input gates and Set-Reset flip-flop logic as well. Moreover, all these logical elements and flip-flop are found to be tolerant to noise. These phenomena are also experimentally demonstrated. Thus, our investigation to realize all logic gates and memory latch in a nonlinear circuit system paves the way to replace or complement the existing technology with a limited number of hardware.
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Affiliation(s)
- P Ashokkumar
- PG & Research Department of Physics, Nehru Memorial College (Autonomous), Affiliated to Bharathidasan University, Puthanampatti, Tiruchirappalli 621 007, India
| | - M Sathish Aravindh
- PG & Research Department of Physics, Nehru Memorial College (Autonomous), Affiliated to Bharathidasan University, Puthanampatti, Tiruchirappalli 621 007, India
| | - A Venkatesan
- PG & Research Department of Physics, Nehru Memorial College (Autonomous), Affiliated to Bharathidasan University, Puthanampatti, Tiruchirappalli 621 007, India
| | - M Lakshmanan
- Department of Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620 024, India
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Le Thi HY, Khan MA, Venkatesan A, Watanabe K, Taniguchi T, Kim GH. High-performance ambipolar MoS 2transistor enabled by indium edge contacts. Nanotechnology 2021; 32:215701. [PMID: 33556924 DOI: 10.1088/1361-6528/abe438] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
The integration of electrical contact into 2D heterostructure is an essential approach to high-quality electronic nano-devices, especially field-effect transistors. However, high contact resistance with transition metal dichalcogenides such as molybdenum disulphide (MoS2)-based devices has been a significant fabrication impediment to their potential applications. Here, we have demonstrated the advantage of 1D indium metal contact with fully encapsulated MoS2within hexagonal boron nitride. The electrical measurements of the device exhibit ambipolar transport with an on/off ratio of102for holes and107for electrons. The device exhibits high field-effect mobility of40.7cm2V-1s-1at liquid nitrogen temperature. Furthermore, we have also analysed the charge-transport mechanism at the interface and have calculated the Schottky barrier height from the temperature-dependent measurement. These results are highly promising for the use of air-sensitive material heterostructure and large-scale design of trending flexible, transparent electronic wearable devices.
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Affiliation(s)
- Hai Yen Le Thi
- Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Muhammad Atif Khan
- Department of Electrical and Computer Engineering, Air University, Sector E-9, Islamabad, Pakistan
| | - A Venkatesan
- School of Electronic and Electrical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Material Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Gil-Ho Kim
- Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
- School of Electronic and Electrical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
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Ankaiah D, Mitra S, Srivastava D, Sivagnanavelmurugan M, Ayyanna R, Jha N, Venkatesan A. Probiotic characterization of bacterial strains from fermented South Indian tomato pickle and country chicken intestine having antioxidative and antiproliferative activities. J Appl Microbiol 2021; 131:949-963. [PMID: 33404172 DOI: 10.1111/jam.14991] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/07/2020] [Accepted: 12/28/2020] [Indexed: 12/31/2022]
Abstract
AIM The present study aims to evaluate the potential antioxidant and antiproliferative properties of probiotic bacterial isolates Weissella cibaria p3B, Bacillus subtilis CS, and Bacillus tequilensis CL, isolated from South Indian fermented tomato pickle (homemade) and gut content of indigenous country chicken. METHODS AND RESULTS The bacterial isolates exhibited antimicrobial activity against food-borne, human pathogenic bacteria, along with better survival under different bile and acidic conditions, hydrophobicity towards several hydrocarbons, and adherence to intestinal epithelial cells (INT-407 cells). Also, the intact cell (IC) mixture of the three species showed better DPPH, ABTS, and Fe2+ chelating activity as compared to the individual IC or cell extract (CE) activity. Among the three bacterial species, W. cibaria p3B revealed maximum antiproliferative activity against HeLa and Caco-2 cancer cells, all of which were nontoxic to INT-407 cells. Apart from being non-hemolytic, the bacterial isolates did not display any necrotic inhibition in HeLa and Caco-2 cells. The cell free supernatant (CFS) of the three bacterial isolates were tested for the production of antimicrobial peptides or bacteriocins. It found that the CFS of bacterial isolates was stable at various temperature, pH and sensitive to proteolytic enzymes confirms protenoius in nature of the antimicrobil peptides or bacteriocins. CONCLUSION The bacterial isolates showed promising antimicrobial, antioxidant as well as antiproliferative activities with better survival ability at different pH and bile concentrations. The three bacterial isolates were able to produce potential antimicrobial peptides or bacteriocins. SIGNIFICANCE AND IMPACT OF THE STUDY These results indicate better compatibility of our bacterial isolates against synthetic drugs to avoid adverse side effects and can be processed as dietary supplements against food and human pathogens. They can also provide antioxidative and antiproliferative benefits to humans and animals.
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Affiliation(s)
- D Ankaiah
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - S Mitra
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - D Srivastava
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - M Sivagnanavelmurugan
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - R Ayyanna
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - N Jha
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - A Venkatesan
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry, India
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Sanders J, Venkatesan A, Davis J, Kudchadker R, Tang C, Bruno T, Ma J, Frank S. OC-1040: Computer aided brachytherapy: assisting the practice of prostate brachytherapy with machine learning. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(21)01977-0] [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]
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De B, Venkatesan A, Msaouel P, Ghia A, Li J, Yeboa D, Nguyen Q, Bishop A, Jonasch E, Shah A, Campbell M, Wang J, Zurita-Saavedra A, Karam J, Wood C, Matin S, Tannir N, Tang C. Definitive Radiotherapy for Oligoprogressive Metastatic Renal Cell Carcinoma as a Strategy to Defer Systemic Therapy Escalation. Int J Radiat Oncol Biol Phys 2020. [DOI: 10.1016/j.ijrobp.2020.07.450] [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]
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Sanders J, Frank S, Venkatesan A, Bathala T, Tang C, Kudchadker R, Bruno T, Pagel M, Ma J. OC-1034: Parallel imaging compressed sensing for prostate MRI without an endorectal coil: a prospective study. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(21)01973-3] [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: 10/22/2022]
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14
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Rigaud B, Anderson B, Cazoulat G, Yu Z, Soderberg J, Samuelsson E, Ward C, Svensson S, Taku N, Lofman F, Venkatesan A, Klopp A, Brock K. Automatic Segmentation Using Deep Learning for Online Dose Optimization During Adaptive Radiotherapy of Cervical Cancer. Int J Radiat Oncol Biol Phys 2020. [DOI: 10.1016/j.ijrobp.2020.07.2573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Sathish Aravindh M, Venkatesan A, Lakshmanan M. Route to logical strange nonchaotic attractors with single periodic force and noise. Chaos 2020; 30:093137. [PMID: 33003915 DOI: 10.1063/5.0017725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/04/2020] [Indexed: 06/11/2023]
Abstract
Strange nonchaotic attractors (SNAs) have been identified and studied in the literature exclusively in quasiperiodically driven nonlinear dynamical systems. It is an interesting question to ask whether they can be identified with other types of forcings as well, which still remains an open problem. Here, we show that robust SNAs can be created by a small amount of noise in periodically driven nonlinear dynamical systems by a single force. The robustness of these attractors is tested by perturbing the system with logical signals, leading to the emulation of different logical elements in the SNA regions.
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Affiliation(s)
- M Sathish Aravindh
- PG & Research Department of Physics, Nehru Memorial College (Autonomous), Affiliated to Bharathidasan University, Puthanampatti, Tiruchirappalli 621 007, India
| | - A Venkatesan
- PG & Research Department of Physics, Nehru Memorial College (Autonomous), Affiliated to Bharathidasan University, Puthanampatti, Tiruchirappalli 621 007, India
| | - M Lakshmanan
- Department of Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620 024, India
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Venkatesan A. Influence of Tannery Effluents on Morphological Characters of Ipomoea pes-caprae (L.) Sweet and Clerodendron inerme (L.) Gaertn. NEPT 2020. [DOI: 10.46488/nept.2020.v19i02.032] [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: 11/20/2022] Open
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Rigaud B, Klopp A, Vedam S, Venkatesan A, Taku N, Simon A, Haigron P, de Crevoisier R, Brock KK, Cazoulat G. Deformable image registration for dose mapping between external beam radiotherapy and brachytherapy images of cervical cancer. Phys Med Biol 2019; 64:115023. [PMID: 30913542 DOI: 10.1088/1361-6560/ab1378] [Citation(s) in RCA: 12] [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] [Indexed: 02/07/2023]
Abstract
For locally advanced cervical cancer (LACC), anatomy correspondence with and without BT applicator needs to be quantified to merge the delivered doses of external beam radiation therapy (EBRT) and brachytherapy (BT). This study proposed and evaluated different deformable image registration (DIR) methods for this application. Twenty patients who underwent EBRT and BT for LACC were retrospectively analyzed. Each patient had a pre-BT CT at EBRT boost (without applicator) and a CT and MRI at BT (with applicator). The evaluated DIR methods were the diffeomorphic Demons, commercial intensity and hybrid methods, and three different biomechanical models. The biomechanical models considered different boundary conditions (BCs). The impact of the BT devices insertion on the anatomy was quantified. DIR method performances were quantified using geometric criteria between the original and deformed contours. The BT dose was deformed toward the pre-CT BT by each DIR method. The impact of boundary conditions to drive the biomechanical model was evaluated based on the deformation vector field and dose differences. The GEC-ESTRO guideline dose indices were reported. Large organ displacements, deformations, and volume variations were observed between the pre-BT and BT anatomies. Rigid registration and intensity-based DIR resulted in poor geometric accuracy with mean Dice similarity coefficient (DSC) inferior to 0.57, 0.63, 0.42, 0.32, and 0.43 for the rectum, bladder, vagina, cervix and uterus, respectively. Biomechanical models provided a mean DSC of 0.96 for all the organs. By considering the cervix-uterus as one single structure, biomechanical models provided a mean DSC of 0.88 and 0.94 for the cervix and uterus, respectively. The deformed doses were represented for each DIR method. Caution should be used when performing DIR for this application as standard techniques may have unacceptable results. The biomechanical model with the cervix-uterus as one structure provided the most realistic deformations to propagate the BT dose toward the EBRT boost anatomy.
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Affiliation(s)
- B Rigaud
- Univ Rennes, CLCC Eugène Marquis, Inserm, LTSI-UMR 1099, F-35000 Rennes, France. Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America. Author to whom any correspondence should be addressed
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18
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Cherupanakkal C, Samadanam DM, Muthuraman KR, Ramesh S, Venkatesan A, Balakrishna Pillai AK, Rajendiran S. Lipid peroxidation, DNA damage, and apoptosis in dengue fever. IUBMB Life 2018; 70:1133-1143. [DOI: 10.1002/iub.1925] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 07/04/2018] [Accepted: 07/07/2018] [Indexed: 01/06/2023]
Affiliation(s)
- Cleetus Cherupanakkal
- Department of Biochemistry; Jawaharlal Institute of Postgraduate Medicine and Research; Puducherry India
| | - Daisy Mariya Samadanam
- Department of Biochemistry; Jawaharlal Institute of Postgraduate Medicine and Research; Puducherry India
| | - Krishna Raja Muthuraman
- Department of Biochemistry; Jawaharlal Institute of Postgraduate Medicine and Research; Puducherry India
| | - Surya Ramesh
- School of Chemical and Biotechnology; SASTRA University; Thanjavur Tamil Nadu India
| | - Amrit Venkatesan
- Central Inter-Disciplinary Research Facility (CIDRF); A Unit of Sri Balaji Vidyapeeth (Deemed to-be University) Educational and Charitable Public Trust; Puducherry India
| | - Agiesh Kumar Balakrishna Pillai
- Central Inter-Disciplinary Research Facility (CIDRF); A Unit of Sri Balaji Vidyapeeth (Deemed to-be University) Educational and Charitable Public Trust; Puducherry India
| | - Soundravally Rajendiran
- Department of Biochemistry; Jawaharlal Institute of Postgraduate Medicine and Research; Puducherry India
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19
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Abstract
We investigate the response of quasiperiodically driven nonlinear systems exhibiting strange nonchaotic attractors (SNAs) to deterministic input signals. We show that if one uses two square waves in an aperiodic manner as input to a quasiperiodically driven double-well Duffing oscillator system, the response of the system can produce logical output controlled by such a forcing. Changing the threshold or biasing of the system changes the output to another logic operation and memory latch. The interplay of nonlinearity and quasiperiodic forcing yields logical behavior, and the emergent outcome of such a system is a logic gate. It is further shown that the logical behaviors persist even for an experimental noise floor. Thus the SNA turns out to be an efficient tool for computation.
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Affiliation(s)
- M Sathish Aravindh
- PG and Research Department of Physics, Nehru Memorial College (Autonomous), Puthanampatti, Tiruchirappalli 621 007, India
- Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620 024, India
| | - A Venkatesan
- PG and Research Department of Physics, Nehru Memorial College (Autonomous), Puthanampatti, Tiruchirappalli 621 007, India
| | - M Lakshmanan
- Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620 024, India
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20
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Venkatesan A, Rathi S, Lee IY, Park J, Lim D, Kang M, Joh HI, Kim GH, Kannan ES. Molybdenum disulfide nanoparticles decorated reduced graphene oxide: highly sensitive and selective hydrogen sensor. Nanotechnology 2017; 28:365501. [PMID: 28675152 DOI: 10.1088/1361-6528/aa7d66] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this work, we report on the hydrogen (H2) sensing behavior of reduced graphene oxide (RGO)/molybdenum disulfide (MoS2) nano particles (NPs) based composite film. The RGO/MoS2 composite exhibited a highly enhanced H2 response (∼15.6%) for 200 ppm at an operating temperature of 60 °C. Furthermore, the RGO/MoS2 composite showed excellent selectivity to H2 with respect to ammonia (NH3) and nitric oxide (NO) which are highly reactive gas species. The composite's response to H2 is 2.9 times higher than that of NH3 whereas for NO it is 3.5. This highly improved H2 sensing response and selectivity of RGO/MoS2 at low operating temperatures were attributed to the structural integration of MoS2 nanoparticles in the nanochannels and pores in the RGO layer.
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Affiliation(s)
- A Venkatesan
- Department of Physics, BITS-Pilani, K. K. Birla Goa Campus, Zuarinagar, Goa 403726, India
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21
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Venkatesh PR, Venkatesan A, Lakshmanan M. Implementation of dynamic dual input multiple output logic gate via resonance in globally coupled Duffing oscillators. Chaos 2017; 27:083106. [PMID: 28863500 DOI: 10.1063/1.4997758] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We have used a system of globally coupled double-well Duffing oscillators under an enhanced resonance condition to design and implement Dual Input Multiple Output (DIMO) logic gates. In order to enhance the resonance, the first oscillator in the globally coupled system alone is excited by two forces out of which one acts as a driving force and the other will be either sub-harmonic or super-harmonic in nature. We report that for an appropriate coupling strength, the second force coherently drives and enhances not only the amplitude of the weak first force to all the coupled systems but also drives and propagates the digital signals if any given to the first system. We then numerically confirm the propagation of any digital signal or square wave without any attenuation under an enhanced resonance condition for an amplitude greater than a threshold value. Further, we extend this idea for computing various logical operations and succeed in designing theoretically DIMO logic gates such as AND/NAND, OR/NOR gates with globally coupled systems.
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Affiliation(s)
- P R Venkatesh
- PG & Research Department of Physics, Nehru Memorial College (Autonomous), Puthanampatti, Tiruchirapalli 621 007, India
| | - A Venkatesan
- PG & Research Department of Physics, Nehru Memorial College (Autonomous), Puthanampatti, Tiruchirapalli 621 007, India
| | - M Lakshmanan
- Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620 024, India
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22
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Bomila R, Srinivasan S, Venkatesan A, Bharath B, Perinbam K. Structural, optical and antibacterial activity studies of Ce-doped ZnO nanoparticles prepared by wet-chemical method. ACTA ACUST UNITED AC 2017. [DOI: 10.1080/14328917.2017.1324379] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- R. Bomila
- Department of Physics, Presidency College, Chennai, India
| | - S. Srinivasan
- Department of Physics, Presidency College, Chennai, India
| | - A. Venkatesan
- Department of Physics, Panimalar Engineering College, Chennai, India
| | - B. Bharath
- Department of Botany, Govt. Arts College for Men, Chennai, India
| | - K. Perinbam
- Department of Botany, Govt. Arts College for Men, Chennai, India
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23
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Venkatesh PR, Venkatesan A, Lakshmanan M. Design and implementation of dynamic logic gates and R-S flip-flop using quasiperiodically driven Murali-Lakshmanan-Chua circuit. Chaos 2017; 27:033105. [PMID: 28364764 DOI: 10.1063/1.4977977] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report the propagation of a square wave signal in a quasi-periodically driven Murali-Lakshmanan-Chua (QPDMLC) circuit system. It is observed that signal propagation is possible only above a certain threshold strength of the square wave or digital signal and all the values above the threshold amplitude are termed as "region of signal propagation." Then, we extend this region of signal propagation to perform various logical operations like AND/NAND/OR/NOR and hence it is also designated as the "region of logical operation." Based on this region, we propose implementing the dynamic logic gates, namely, AND/NAND/OR/NOR, which can be decided by the asymmetrical input square waves without altering the system parameters. Further, we show that a single QPDMLC system will produce simultaneously two outputs which are complementary to each other. As a result, a single QPDMLC system yields either AND as well as NAND or OR as well as NOR gates simultaneously. Then, we combine the corresponding two QPDMLC systems in a cross-coupled way and report that its dynamics mimics that of fundamental R-S flip-flop circuit. All these phenomena have been explained with analytical solutions of the circuit equations characterizing the system and finally, the results are compared with the corresponding numerical and experimental analysis.
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Affiliation(s)
- P R Venkatesh
- PG & Research Department of Physics, Nehru Memorial College (Autonomous), Puthanampatti, Tiruchirapalli 621 007, India
| | - A Venkatesan
- PG & Research Department of Physics, Nehru Memorial College (Autonomous), Puthanampatti, Tiruchirapalli 621 007, India
| | - M Lakshmanan
- Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620 024, India
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24
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Koelman DLH, Benkeser DC, Xu Y, Neo SX, Tan K, Katsuno M, Sobue G, Natsume J, Chahin S, Mar SS, Venkatesan A, Chitnis T, Hoganson GM, Yeshokumar AK, Barreras P, Majmudar B, Carone M, Mateen FJ. Acute disseminated encephalomyelitis in China, Singapore and Japan: a comparison with the USA. Eur J Neurol 2016; 24:391-396. [DOI: 10.1111/ene.13220] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/25/2016] [Indexed: 10/20/2022]
Affiliation(s)
- D. L. H. Koelman
- Department of Neurology; Massachusetts General Hospital; Boston MA USA
- Academic Medical Center - University of Amsterdam; Amsterdam The Netherlands
| | - D. C. Benkeser
- Group in Biostatistics; University of California, Berkeley; Berkeley CA USA
| | - Y. Xu
- Department of Neurology; Peking Union Medical College Hospital; Beijing China
| | - S. X. Neo
- Department of Neurology; National Neuroscience Institute; Singapore Singapore
| | - K. Tan
- Department of Neurology; National Neuroscience Institute; Singapore Singapore
| | - M. Katsuno
- Department of Neurology; Nagoya University Graduate School of Medicine; Nagoya Japan
| | - G. Sobue
- Department of Neurology; Nagoya University Graduate School of Medicine; Nagoya Japan
| | - J. Natsume
- Department of Developmental Disability Medicine; Nagoya University Graduate School of Medicine; Nagoya Japan
| | - S. Chahin
- Department of Neurology; University of Pennsylvania; Philadelphia PA USA
| | - S. S. Mar
- Department of Neurology; Washington University School of Medicine; St Louis MO USA
| | - A. Venkatesan
- Department of Neurology; Johns Hopkins University School of Medicine; Baltimore MD USA
| | - T. Chitnis
- Department of Neurology; Brigham and Women's Hospital; Boston MA USA
- Department of Pediatric Neurology; Massachusetts General Hospital; Boston MA USA
| | - G. M. Hoganson
- Department of Neurology; Washington University School of Medicine; St Louis MO USA
| | - A. K. Yeshokumar
- Department of Neurology; Johns Hopkins University School of Medicine; Baltimore MD USA
| | - P. Barreras
- Department of Neurology; Johns Hopkins University School of Medicine; Baltimore MD USA
| | - B. Majmudar
- Department of Neurology; Washington University School of Medicine; St Louis MO USA
| | - M. Carone
- Department of Biostatistics; University of Washington; Seattle WA USA
| | - F. J. Mateen
- Department of Neurology; Massachusetts General Hospital; Boston MA USA
- Harvard Medical School; Boston MA USA
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25
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Sivakumar S, Venkatesan A, Soundhirarajan P, Khatiwada CP. Thermal, structural, functional, optical and magnetic studies of pure and Ba doped CdO nanoparticles. Spectrochim Acta A Mol Biomol Spectrosc 2015; 151:760-772. [PMID: 26172463 DOI: 10.1016/j.saa.2015.06.105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [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: 11/25/2014] [Revised: 06/25/2015] [Accepted: 06/26/2015] [Indexed: 06/04/2023]
Abstract
In this research, a chemical precipitation method was used to synthesize undoped and doped cadmium oxide nanoparticles and studied by TG-DTA, XRD, FT-IR, SEM, with EDX and antibacterial activities, respectively. The melting points, thermal stability and the kinetic parameters like entropy (ΔS), enthalpy (ΔH), Gibb's energy (ΔG), activation energy (E), frequency factor (A) were evaluated from TG-DTA measurements. X-ray diffraction analysis (XRD) brought out the information about the synthesized products exist in spherical in shape with cubic structure. The functional groups and band area of the samples were established by Fourier transform infrared (FT-IR) spectroscopy. The direct and indirect band gap energy of pure and doped samples were determined by UV-Vis-DRS. The surface morphological, elemental compositions and particles sizes were evaluated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Finally, antibacterial activities indicated the Gram-positive and Gram-negative bacteria are more active in transporter, dehydrogenize and periplasmic enzymatic activities of pure and doped samples.
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Affiliation(s)
- S Sivakumar
- Department of Physics, Annamalai University, Annamalai Nagar, Tamil Nadu 608 002, India.
| | - A Venkatesan
- Department of Physics, Annamalai University, Annamalai Nagar, Tamil Nadu 608 002, India
| | - P Soundhirarajan
- Department of Physics, Annamalai University, Annamalai Nagar, Tamil Nadu 608 002, India
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26
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Sivakumar S, Soundhirarajan P, Venkatesan A, Khatiwada CP. Spectroscopic studies and antibacterial activities of pure and various levels of Cu-doped BaSO₄ nanoparticles. Spectrochim Acta A Mol Biomol Spectrosc 2015; 151:895-907. [PMID: 26184475 DOI: 10.1016/j.saa.2015.07.048] [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] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 07/03/2015] [Accepted: 07/08/2015] [Indexed: 05/16/2023]
Abstract
The present study was made to design the pure and various levels of Cu doped (0.025 M, 0.05 M and 0.075 M) BaSO4 NPs synthesized by chemical precipitation method. The synthesized products have been characterised by X-ray Diffractometer (XRD), Fourier transform infrared (FT-IR) spectrometer, thermogravimetric and differential thermal analysis (TG-DTA), UV-Vis-diffused reflectance spectroscopy (UV-Vis-DRS), field emission-scanning electron microscopy with energy dispersive spectroscopy (FE-SEM with EDS), transmission electron microscopy (TEM) and application oriented study like antibacterial activity also reported. The result determined from XRD was affirmed by the results obtained from electron microscopic measurements. XRD study revealed that the synthesized products were composed of orthorhombic structure and highly crystalline in nature. Furthermore, flaky like morphology of pure and Cu-BaSO4 nanoparticles have been observed from the images obtained from these studies. The existence of Cu(2+) was confirmed by EDS analysis. The functional groups of the synthesized samples were analysed by FT-IR study. The band gap energies of pure and doped samples were accomplished using UV-Vis-DRS analysis. Also, the kinetic parameters were evaluated and reported from the thermal stability of nanoparticles. Eventually, gram-negative bacteria shows the less antibacterial activities compared to gram-positive bacteria due to adsorption of BaSO4 nanoparticles on the surface of the used bacteria.
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Affiliation(s)
- S Sivakumar
- Department of Physics, Annamalai University, Annamalai Nagar 608 002, Tamil Nadu, India.
| | - P Soundhirarajan
- Department of Physics, Annamalai University, Annamalai Nagar 608 002, Tamil Nadu, India
| | - A Venkatesan
- Department of Physics, Annamalai University, Annamalai Nagar 608 002, Tamil Nadu, India
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27
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Gopal R, Chandrasekar VK, Senthilkumar DV, Venkatesan A, Lakshmanan M. Effect of asymmetry parameter on the dynamical states of nonlocally coupled nonlinear oscillators. Phys Rev E Stat Nonlin Soft Matter Phys 2015; 91:062916. [PMID: 26172781 DOI: 10.1103/physreve.91.062916] [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] [Received: 02/17/2015] [Indexed: 06/04/2023]
Abstract
We show that coexisting domains of coherent and incoherent oscillations can be induced in an ensemble of any identical nonlinear dynamical systems using nonlocal rotational matrix coupling with an asymmetry parameter. Further, a chimera is shown to emerge in a wide range of the asymmetry parameter in contrast to near π/2 values of it employed in earlier works. We have also corroborated our results using the strength of incoherence in the frequency domain (S(ω)) and in the amplitude domain (S), thereby distinguishing the frequency and amplitude chimeras. The robust nature of the asymmetry parameter in inducing chimeras in any generic dynamical system is established using ensembles of identical Rössler oscillators, Lorenz systems, and Hindmarsh-Rose neurons in their chaotic regimes.
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Affiliation(s)
- R Gopal
- Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620 024, India
- Department of Physics, Nehru Memorial College, Puthanampatti, Tiruchirapalli 621 007, India
| | - V K Chandrasekar
- Centre for Nonlinear Science & Engineering, School of Electrical & Electronics Engineering, SASTRA University, Thanjavur 613 401, India
| | - D V Senthilkumar
- Centre for Nonlinear Science & Engineering, School of Electrical & Electronics Engineering, SASTRA University, Thanjavur 613 401, India
| | - A Venkatesan
- Department of Physics, Nehru Memorial College, Puthanampatti, Tiruchirapalli 621 007, India
| | - M Lakshmanan
- Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620 024, India
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28
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Patri S, Mohana M, Kameswari K, Kumar SS, Narmadha S, Vijayshree R, Meikandamurthy C, Venkatesan A, Palanisami K, Murthy DT, Babu B, Prakash V, Rajan K. Simplified method for measuring the response time of scram release electromagnet in a nuclear reactor. Nuclear Engineering and Design 2015. [DOI: 10.1016/j.nucengdes.2015.01.010] [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: 11/29/2022]
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Sivakumar S, Soundhirarajan P, Venkatesan A, Khatiwada CP. Synthesis, characterization and anti-bacterial activities of pure and Co-doped BaSO4 nanoparticles via chemical precipitation route. Spectrochim Acta A Mol Biomol Spectrosc 2015; 137:137-147. [PMID: 25218222 DOI: 10.1016/j.saa.2014.08.080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [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: 06/06/2014] [Revised: 08/08/2014] [Accepted: 08/23/2014] [Indexed: 06/03/2023]
Abstract
In the present study, we reported that the synthesis and characterization of pure and diverse mole Co-doped BaSO4 nanoparticles have been synthesized by chemical precipitation technique. X-ray diffraction analysis (XRD) brought out the information about the synthesized products is orthorhombic structure and highly crystalline in nature. The average grain size of the samples was determined by using the Debye-Scherer's equation. The existence of functional groups and band area of the samples were confirmed by Fourier transform infrared (FTIR) spectroscopy. The direct and indirect band gap energy of pure and doped samples was carried out using UV-VIS-DRS. The surface micrograph, morphological distribution and elemental compositions of the synthesized products were assessed by scanning electron microscopy (SEM) and Energy dispersive X-ray (EDS). Thermo gravimetric and differential thermal analysis (TG-DTA) techniques were analyzed thermal behaviour of pure and Co-doped samples. Finally, antibacterial activities found the Gram-positive and Gram-negative bacteria are more active in transporter, dehydrogenize and periplasmic enzymatic activities of pure and doped samples.
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Affiliation(s)
- S Sivakumar
- Department of Physics, Annamalai University, Annamalai Nagar, Tamil Nadu 608 002, India.
| | - P Soundhirarajan
- Department of Physics, Annamalai University, Annamalai Nagar, Tamil Nadu 608 002, India
| | - A Venkatesan
- Department of Physics, Annamalai University, Annamalai Nagar, Tamil Nadu 608 002, India
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Sivakumar S, Venkatesan A, Soundhirarajan P, Khatiwada CP. Synthesis, characterizations and anti-bacterial activities of pure and Ag doped CdO nanoparticles by chemical precipitation method. Spectrochim Acta A Mol Biomol Spectrosc 2015; 136 Pt C:1751-1759. [PMID: 25467666 DOI: 10.1016/j.saa.2014.10.078] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [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: 08/13/2014] [Revised: 10/12/2014] [Accepted: 10/19/2014] [Indexed: 06/04/2023]
Abstract
In the present study, synthesized pure and Ag (1%, 2%, and 3%) doped Cadmium Oxide (CdO) nanoparticles by chemical precipitation method. Then, the synthesized products were characterized by thermo gravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD) analysis, Fourier transform infrared (FT-IR) spectroscopy, Ultra violet-Vis diffused reflectance spectroscopy (UV-Vis-DRS), Scanning electron microscopy (SEM), Energy dispersive X-rays (EDX) spectroscopy, and anti-bacterial activities, respectively. The transition temperatures and phase transitions of Cd(OH)2 to CdO at 400°C was confirmed by TG-DTA analysis. The XRD patterns show the cubic shape and average particle sizes are 21, 40, 34, and 37nm, respectively for pure and Ag doped samples. FT-IR study confirmed the presence of CdO and Ag at 677 and 459cm(-1), respectively. UV-Vis-DRS study shows the variation on direct and indirect band gaps. The surface morphologies and elemental analysis have been confirmed from SEM and with EDX. In addition, the synthesized products have been characterized by antibacterial activities against Gram-positive and negative bacteria. Further, the present investigation suggests that CdO nanoparticles have the great potential applications on various industrial and medical fields of research.
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Affiliation(s)
- S Sivakumar
- Department of Physics, Annamalai University, Annamalai Nagar, Tamil Nadu 608 002, India.
| | - A Venkatesan
- Department of Physics, Annamalai University, Annamalai Nagar, Tamil Nadu 608 002, India
| | - P Soundhirarajan
- Department of Physics, Annamalai University, Annamalai Nagar, Tamil Nadu 608 002, India
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31
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Chandrasekar VK, Gopal R, Venkatesan A, Lakshmanan M. Mechanism for intensity-induced chimera states in globally coupled oscillators. Phys Rev E Stat Nonlin Soft Matter Phys 2014; 90:062913. [PMID: 25615170 DOI: 10.1103/physreve.90.062913] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Indexed: 06/04/2023]
Abstract
We identify the mechanism behind the existence of intensity-induced chimera states in globally coupled oscillators. We find that the effect of intensity in the system is to cause multistability by increasing the number of fixed points. This in turn increases the number of multistable attractors, and we find that their stability is determined by the strength of coupling. This causes the coexistence of different collective states in the system depending upon the initial state. We demonstrate that intensity-induced chimera is generic to both periodic and chaotic systems. We discuss possible applications of our results to real-world systems like the brain and spin torque nano-oscillators.
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Affiliation(s)
- V K Chandrasekar
- Centre for Nonlinear Science & Engineering, School of Electrical & Electronics Engineering, SASTRA University, Thanjavur 613 401, India
| | - R Gopal
- Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620 024, India and Department of Physics, Nehru Memorial College, Puthanampatti, Tiruchirapalli 621 007, India
| | - A Venkatesan
- Department of Physics, Nehru Memorial College, Puthanampatti, Tiruchirapalli 621 007, India
| | - M Lakshmanan
- Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620 024, India
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Sivakumar S, Anusuya D, Khatiwada CP, Sivasubramanian J, Venkatesan A, Soundhirarajan P. Characterizations of diverse mole of pure and Ni-doped α-Fe2O3 synthesized nanoparticles through chemical precipitation route. Spectrochim Acta A Mol Biomol Spectrosc 2014; 128:69-75. [PMID: 24681311 DOI: 10.1016/j.saa.2014.02.136] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [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: 11/06/2013] [Revised: 02/11/2014] [Accepted: 02/21/2014] [Indexed: 06/03/2023]
Abstract
In the present study, an attempt has been made for characterization and synthesis of pure and Ni-doped α-Fe2O3 (hematite) nanoparticles by chemical precipitation method. The synthesized products have been studied by X-ray diffraction (X-RD), Fourier transform infrared (FTIR) spectroscopy, UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), vibrating sample magnetometer (VSM) and scanning electron microscopy (SEM) techniques. The estimated average diameter of α-Fe2O3 nanoparticles were calculated by using the Debye-Scherrer equation and established as 31 nm. SEM micrographs showed the surface morphology as well as structures and particles distributions of synthesized samples. The UV-Vis DRS showed the indirect and direct band gap energies of pure and Ni-doped α-Fe2O3, these were reduced from 1.9847 to 1.52 eV and 2.0503 to 1.76 eV respectively. This result suggested the dopant enhanced the semiconducting behavior of iron oxide nanoparticles to an extent proportional to its nickel doped in the α-Fe2O3. Further, the magnetic properties of the pure and doped samples were investigated by vibrating sample magnetometer (VSM) and evaluated the information of pure and doped samples exhibited saturated hysteresis loop at room temperature, which is indicating that the weak ferromagnetism in nature of our synthesized samples. In addition, it has been found from the magnetization hysteresis curves of Ni-doping, resulting from increased the saturation of magnetization and reduced the coercivity of used samples. Therefore, the present study showed the reduction in band gap energies and coercive field for α-Fe2O3 nanoparticles due to nickel doped.
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Affiliation(s)
- S Sivakumar
- Department of Physics, Annamalai University, Annamalai Nagar, Tamilnadu 608 002, India.
| | - D Anusuya
- Department of Physics, Annamalai University, Annamalai Nagar, Tamilnadu 608 002, India
| | | | - J Sivasubramanian
- Department of Physics, Annamalai University, Annamalai Nagar, Tamilnadu 608 002, India
| | - A Venkatesan
- Department of Physics, Annamalai University, Annamalai Nagar, Tamilnadu 608 002, India
| | - P Soundhirarajan
- Department of Physics, Annamalai University, Annamalai Nagar, Tamilnadu 608 002, India
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Venkatesan A, Glaser CA. Reply to Tardieu et al. Clin Infect Dis 2014; 58:1493. [DOI: 10.1093/cid/ciu124] [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: 11/14/2022] Open
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Gopal R, Chandrasekar VK, Venkatesan A, Lakshmanan M. Observation and characterization of chimera states in coupled dynamical systems with nonlocal coupling. Phys Rev E Stat Nonlin Soft Matter Phys 2014; 89:052914. [PMID: 25353868 DOI: 10.1103/physreve.89.052914] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Indexed: 06/04/2023]
Abstract
By developing the concepts of strength of incoherence and discontinuity measure, we show that a distinct quantitative characterization of chimera and multichimera states which occur in networks of coupled nonlinear dynamical systems admitting nonlocal interactions of finite radius can be made. These measures also clearly distinguish between chimera or multichimera states (both stable and breathing types) and coherent and incoherent as well as cluster states. The measures provide a straightforward and precise characterization of the various dynamical states in coupled chaotic dynamical systems irrespective of the complexity of the underlying attractors.
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Affiliation(s)
- R Gopal
- Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli-620024, India
| | - V K Chandrasekar
- Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli-620024, India
| | - A Venkatesan
- Department of Physics, Nehru Memorial College, Puthanampatti, Tiruchirapalli 621 007, India
| | - M Lakshmanan
- Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli-620024, India
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Venkatesan A, Tunkel AR, Bloch KC, Lauring AS, Sejvar J, Bitnun A, Stahl JP, Mailles A, Drebot M, Rupprecht CE, Yoder J, Cope JR, Wilson MR, Whitley RJ, Sullivan J, Granerod J, Jones C, Eastwood K, Ward KN, Durrheim DN, Solbrig MV, Guo-Dong L, Glaser CA. Case definitions, diagnostic algorithms, and priorities in encephalitis: consensus statement of the international encephalitis consortium. Clin Infect Dis 2013; 57:1114-28. [PMID: 23861361 PMCID: PMC3783060 DOI: 10.1093/cid/cit458] [Citation(s) in RCA: 634] [Impact Index Per Article: 57.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/03/2013] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Encephalitis continues to result in substantial morbidity and mortality worldwide. Advances in diagnosis and management have been limited, in part, by a lack of consensus on case definitions, standardized diagnostic approaches, and priorities for research. METHODS In March 2012, the International Encephalitis Consortium, a committee begun in 2010 with members worldwide, held a meeting in Atlanta to discuss recent advances in encephalitis and to set priorities for future study. RESULTS We present a consensus document that proposes a standardized case definition and diagnostic guidelines for evaluation of adults and children with suspected encephalitis. In addition, areas of research priority, including host genetics and selected emerging infections, are discussed. CONCLUSIONS We anticipate that this document, representing a synthesis of our discussions and supported by literature, will serve as a practical aid to clinicians evaluating patients with suspected encephalitis and will identify key areas and approaches to advance our knowledge of encephalitis.
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Affiliation(s)
- A Venkatesan
- Johns Hopkins Encephalitis Center, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Abstract
We show that the recently introduced 0-1 test can successfully distinguish between strange nonchaotic attractors (SNAs) and periodic/quasiperiodic/chaotic attractors, by suitably choosing the arbitrary parameter associated with the translation variables in terms of the golden mean number which avoids resonance with the quasiperiodic force. We further characterize the transition from quasiperiodic to chaotic motion via SNAs in terms of the 0-1 test. We demonstrate that the test helps to detect different dynamical transitions to SNAs from quasiperiodic attractor or the transitions from SNAs to chaos. We illustrate the performance of the 0-1 test in detecting transitions to SNAs in quasiperiodically forced logistic map, cubic map, and Duffing oscillator.
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Affiliation(s)
- R Gopal
- Department of Physics, Nehru Memorial College (Autonomous), Puthanampatti, Tiruchirapalli 621007, India
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Abi-Jaoudeh N, Lee J, Levy E, Venkatesan A, Wood B. Prospective randomized trial comparing cone-beam CT (CBCT) navigation vs. conventional CT for biopsies. J Vasc Interv Radiol 2013. [DOI: 10.1016/j.jvir.2013.01.454] [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: 11/27/2022] Open
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Beattie GC, Glaser CA, Sheriff H, Messenger S, Preas CP, Shahkarami M, Venkatesan A. Encephalitis with thalamic and basal ganglia abnormalities: etiologies, neuroimaging, and potential role of respiratory viruses. Clin Infect Dis 2012. [PMID: 23196954 DOI: 10.1093/cid/cis990] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Encephalitis is a severe neurological syndrome with devastating consequences. Despite extensive testing, the etiology often remains unknown. Involvement of the thalamus or basal ganglia (T/BG) occurs in a subset of patients with encephalitis and may be an important etiological clue. In order to improve diagnosis of T/BG patients, we reviewed this subgroup within the California Encephalitis Project (CEP). METHODS Data from T/BG cases enrolled in CEP were retrospectively reviewed. Cases were stratified by age and grouped by etiological classification: infectious, postinfectious, and noninfectious. Neuroimaging reports were examined and compared between etiologies. RESULTS T/BG neuroimaging abnormalities were reported in 6% of 3236 CEP cases. An etiology was found in 76%: 37% infectious, 16% postinfectious, and 23% noninfectious. The most frequently identified infectious agents were respiratory viruses, accounting for 31%, predominantly in children. Other infections more common in the T/BG group included Creutzfeldt-Jakob disease, arbovirus, and Mycobacterium tuberculosis. Infectious and postinfectious cases had higher median cerebrospinal fluid white blood cell count than noninfectious etiologies. Notably, T/BG neuroimaging characteristics were associated with distinct etiologies. In particular, symmetric hemorrhagic abnormalities involving the thalamus were most frequently found within the respiratory virus group. CONCLUSIONS T/BG involvement in patients with suspected encephalitis was associated with specific etiologies. In addition to agents with established predilection for the T/BG such as M. tuberculosis and arboviruses, a surprisingly high number of cases were associated with respiratory viruses, especially in children. Neuroimaging abnormalities in such patients can aid clinicians in narrowing the etiological scope and in guiding testing.
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Affiliation(s)
- G C Beattie
- Communicable Disease and Emergency Response Branch, California Department of Public Health, Richmond, USA
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Deepak C, Venkatesan A, Ramanathan A. In Search of Mutations of MSX1 Gene in Indian Nonsyndromic Cleft Palate Patients. J Indian Orthod Soc 2012. [DOI: 10.1177/0974909820120107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- C Deepak
- Professor, Department of Orthodontics, Sree Balaji Dental College and Hospital Chennai, Tamil Nadu, India
| | - A Venkatesan
- Formerly Professor and Head, Department of Orthodontics, Tamilnadu Government Dental College and Hospital, Chennai, Tamil Nadu, India
| | - Arvind Ramanathan
- Research Scientists Department of Human Genetics Lab, Sree Balaji Dental College and Hospital, Chennai, Tamil Nadu, India
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Amalou H, Abi-Jaoudeh N, Venkatesan A, Levy E, Xu S, Kadoury S, Kruecker J, Locklin J, Gates S, Lee J, Pinto P, Wood B. Abstract No. 71: Fusion guided biopsy or ablation: clinical trial update in 461 patients. J Vasc Interv Radiol 2012. [DOI: 10.1016/j.jvir.2011.12.109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Ramesh Kumar KR, Shanta Sundari KK, Venkatesan A, Chandrasekar S. Depth of resin penetration into enamel with 3 types of enamel conditioning methods: a confocal microscopic study. Am J Orthod Dentofacial Orthop 2011; 140:479-85. [PMID: 21967934 DOI: 10.1016/j.ajodo.2010.10.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 10/01/2010] [Accepted: 10/01/2010] [Indexed: 10/15/2022]
Abstract
INTRODUCTION The clinical efficiency of a bonding material relies on its bond strength and debonding characteristics; the depth of resin penetration into enamel affects both of these factors. The depth of resin penetration has been previously studied by researchers using laborious, indirect methods, including the scanning electron microscope and the optical microscope. METHODS We used a more direct method, confocal microscopy, to visualize the resin tags in enamel. Thirty maxillary first premolars were selected and divided into 3 groups. In group A, the buccal enamel surfaces were conditioned with 37% phosphoric acid; in group B, a self-etching primer was used; and group C was treated with air abrasion. Transbond XT adhesive (3M Unitek, Monrovia, Calif) was used to bond a modified bracket. Transbond XT primer (3M Unitek) mixed with rhodamine B fluorescent dye (Chennai Chemicals, Chennai, India) was applied in groups A and C. In group B, rhodamine was mixed with self-etching primer. After curing, the brackets were debonded, and the teeth were visualized under the fluorescent channel of the confocal microscope. RESULTS Maximal resin penetration of 53.9 μm was observed in group A, followed by group B at 40.5 μm and group C at 39.9 μm. CONCLUSIONS Confocal microscope evaluation showed that enamel conditioning with 37% phosphoric acid produced greater depths of resin penetration than did self-etching primer or air abrasion.
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Affiliation(s)
- K R Ramesh Kumar
- Department of Orthodontics, Vivekanadha Dental College for Women, Triuchengode, Tamilnadu, India.
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Cettomai D, Hiremath G, Ratchford J, Venkatesan A, Greenberg BM, McGready J, Pardo CA, Kerr DA, Frohman E, Balcer LJ, McArthur JC, Calabresi PA. Associations between retinal nerve fiber layer abnormalities and optic nerve examination. Neurology 2010; 75:1318-25. [PMID: 20810997 DOI: 10.1212/wnl.0b013e3181f735bd] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Retinal nerve fiber layer (RNFL) abnormalities detected by optical coherence tomography (OCT) are useful markers for axonal loss and visual dysfunction in multiple sclerosis (MS), but their role in routine clinical management is not well-studied. METHODS Clinical and OCT examinations were performed on 240 patients attending a neurology clinic. Using OCT 5th percentile to define abnormal RNFL thickness, we compared eyes classified by neurologists as having optic atrophy to RNFL thickness, and afferent pupillary defect (APD) to RNFL thickness ratios of eye pairs. RESULTS Mean RNFL thickness was less in eyes classified by neurologists as having optic atrophy (79.4 ± 21 μm; n=63) vs those without (97.0 ± 15 μm; n=417; p < 0.001, t test) and in eyes with an APD (84.1 ± 16 μm; n=44) than without an APD (95.8 ± 17 μm; n=436; p < 0.001). Physicians' diagnostic accuracy for detecting pallor in eyes with an abnormal RNFL thickness was 79% (sensitivity=0.56; specificity=0.82). Accuracy for detecting a RAPD in patients with mean RNFL ratio (affected eye to unaffected eye) <0.90 was 73% (sensitivity=0.30; specificity=0.86). Ability to detect visual pathway injury via assessment of atrophy and APD differed between neurologists. CONCLUSIONS OCT reveals RNFL abnormality in many patients in whom eyes are not classified by neurologic examiners as having optic atrophy. Further study is needed to define the role of OCT measures in the context of examinations for optic atrophy and APD by neuroophthalmologists. OCT-measured RNFL thickness is likely to have an important future role in the clinical setting.
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Affiliation(s)
- D Cettomai
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, USA
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Klepac Pulanic T, Venkatesan A, Segars J, Partanen A, Merino M, Stratton P. Pilot study of MR-guided high intensity focused ultrasound (MRGHIFU) ablation of uterine fibroids. Fertil Steril 2010. [DOI: 10.1016/j.fertnstert.2010.07.860] [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: 11/25/2022]
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Razjouyan F, Kapoor A, Glossop N, Kruecker J, Xu S, Viswanathan A, Chiesa O, Karanian J, Pritchard W, Levy E, Venkatesan A, Solbiati L, Wood B. Abstract No. 118: A comparison of methods for tracking RFA probes and sensitivity to RF field and temperature. J Vasc Interv Radiol 2010. [DOI: 10.1016/j.jvir.2009.12.271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Frolov SM, Venkatesan A, Yu W, Folk JA, Wegscheider W. Electrical generation of pure spin currents in a two-dimensional electron gas. Phys Rev Lett 2009; 102:116802. [PMID: 19392226 DOI: 10.1103/physrevlett.102.116802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Indexed: 05/27/2023]
Abstract
Pure spin currents are generated and detected in micron-wide channels of a GaAs two-dimensional electron gas, using quantum point contacts in an in-plane magnetic field as injectors and detectors. The enhanced sensitivity to spin transport offered by a nonlocal measurement geometry enables accurate spin current measurements in this widely studied physical system. The polarization of the contacts is used to extract the quantum point contact g factor and provides a test for spontaneous polarization at 0.7 structure. The spin relaxation length in the channel is 30-50 microm over the magnetic field range 3-10 T, much longer than has been reported in GaAs two-dimensional electron gases but shorter than that expected from Dyakonov-Perel relaxation.
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Affiliation(s)
- S M Frolov
- Department of Physics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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Sharma K, Xu S, Glossop N, Dreher M, Kruecker J, Venkatesan A, Locklin J, Dromi S, Pritchard W, Karanian J, Tang T, Neeman Z, Bulow T, Wood B. Abstract No. 310: Steerable Endobronchial Navigation without a Bronchoscope or Fiberoptics. J Vasc Interv Radiol 2008. [DOI: 10.1016/j.jvir.2007.12.356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Abstract
New dentate granule cells are continuously generated from neural progenitor cells and integrated into the existing hippocampal circuitry in the adult mammalian brain through an orchestrated process termed adult neurogenesis. While the exact function remains elusive, adult neurogenesis has been suggested to play important roles in specific cognitive functions. Adult hippocampal neurogenesis is regulated by a variety of physiological and pathological stimulations. Here we review emerging evidence showing that HIV infection and several drugs of abuse result in molecular changes that may affect different aspects of adult hippocampal neurogenesis. These new findings raise the possibility that cognitive dysfunction in the setting of HIV infection or drug abuse may, in part, be related to alterations in hippocampal neurogenesis. A better understanding of how HIV and drugs of abuse affect both molecular and cellular aspects of adult neurogenesis may lead to development of more effective therapeutic interventions for these interlinked epidemics.
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Affiliation(s)
- A Venkatesan
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Venkatesan A, Hemalatha A, Bobby Z, Selvaraj N, Sathiyapriya V. Nonenzymatic glycation of plasma proteins in smokers. Indian J Physiol Pharmacol 2006; 50:403-8. [PMID: 17402271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Glycation is known to play a key role in complications of many pathophysiological processes. The present study was carried out to assess whether there are abnormalities of nonenzymatic glycation of proteins in smokers. Fourteen current smokers and 10 healthy nonsmokers were enrolled for the present study. Fasting plasma glucose, insulin, fructosamine and total plasma glycated proteins were evaluated. A significant rise in the mean levels of fructosamine and total plasma glycated proteins were found in smokers when compared with controls. Significant difference in insulin values was observed between these two groups. When Pearson's correlation analysis was performed, no significant correlation was found between fasting plasma glucose with either fructosamine or total plasma glycated protein levels. These data suggest an increased glycation of proteins in smokers independent of glucose concentration.
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Affiliation(s)
- A Venkatesan
- Department of Biochemistry, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry
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Hemalatha A, Venkatesan A, Bobby Z, Selvaraj N, Sathiyapriya V. Antioxidant response to oxidative stress induced by smoking. Indian J Physiol Pharmacol 2006; 50:416-20. [PMID: 17402273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Oxygen free radicals have been hypothesized to play a pivotal role in the deleterious effects of smoking on health. The present study was undertaken to examine the oxidant and antioxidant system among smokers and nonsmokers. Fourteen smokers and 11 nonsmokers were enrolled for this study. The protein carbonyl levels in smokers were found to be significantly higher than in nonsmokers. The levels of plasma ascorbic acid, free sulfhydryl group, and erythrocyte reduced glutathione were lower in smokers compared to nonsmokers. In smokers the erythrocyte activities of both glutathione peroxidase and catalase were decreased when compared to that in nonsmokers. The data from the study reemphasizes the presence of oxidative stress in smokers. The concomitant decrease in the activities of both catalase and glutathione peroxidase found in the erythrocytes of smokers raises rational grounds for expressing concern over the increased susceptibility towards oxidative stress in these subjects.
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Affiliation(s)
- A Hemalatha
- Department of Biochemistry, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry
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Thamilmaran K, Senthilkumar DV, Venkatesan A, Lakshmanan M. Experimental realization of strange nonchaotic attractors in a quasiperiodically forced electronic circuit. Phys Rev E Stat Nonlin Soft Matter Phys 2006; 74:036205. [PMID: 17025727 DOI: 10.1103/physreve.74.036205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Indexed: 05/12/2023]
Abstract
We have identified the three prominent routes, namely Heagy-Hammel, fractalization, and intermittency routes, and their mechanisms for the birth of strange nonchaotic attractors (SNAs) in a quasiperiodically forced electronic system constructed using a negative conductance series LCR circuit with a diode both numerically and experimentally. The birth of SNAs by these three routes is verified from both experimental and their corresponding numerical data by maximal Lyapunov exponents, and their variance, Poincaré maps, Fourier amplitude spectrum, spectral distribution function, and finite-time Lyapunov exponents. Although these three routes have been identified numerically in different dynamical systems, the experimental observation of all these mechanisms is reported here in a single second order electronic circuit.
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Affiliation(s)
- K Thamilmaran
- Center for Nonlinear Dynamics, Department of Physics, Bharathidasan University, Tiruchirapalli 620 024, India
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