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Satheesh Kumar J, Vinoth Kumar V, Mahesh TR, Alqahtani MS, Prabhavathy P, Manikandan K, Guluwadi S. Detection of Marchiafava Bignami disease using distinct deep learning techniques in medical diagnostics. BMC Med Imaging 2024; 24:100. [PMID: 38684964 PMCID: PMC11059769 DOI: 10.1186/s12880-024-01283-8] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 04/25/2024] [Indexed: 05/02/2024] Open
Abstract
PURPOSE To detect the Marchiafava Bignami Disease (MBD) using a distinct deep learning technique. BACKGROUND Advanced deep learning methods are becoming more crucial in contemporary medical diagnostics, particularly for detecting intricate and uncommon neurological illnesses such as MBD. This rare neurodegenerative disorder, sometimes associated with persistent alcoholism, is characterized by the loss of myelin or tissue death in the corpus callosum. It poses significant diagnostic difficulties owing to its infrequency and the subtle signs it exhibits in its first stages, both clinically and on radiological scans. METHODS The novel method of Variational Autoencoders (VAEs) in conjunction with attention mechanisms is used to identify MBD peculiar diseases accurately. VAEs are well-known for their proficiency in unsupervised learning and anomaly detection. They excel at analyzing extensive brain imaging datasets to uncover subtle patterns and abnormalities that traditional diagnostic approaches may overlook, especially those related to specific diseases. The use of attention mechanisms enhances this technique, enabling the model to concentrate on the most crucial elements of the imaging data, similar to the discerning observation of a skilled radiologist. Thus, we utilized the VAE with attention mechanisms in this study to detect MBD. Such a combination enables the prompt identification of MBD and assists in formulating more customized and efficient treatment strategies. RESULTS A significant breakthrough in this field is the creation of a VAE equipped with attention mechanisms, which has shown outstanding performance by achieving accuracy rates of over 90% in accurately differentiating MBD from other neurodegenerative disorders. CONCLUSION This model, which underwent training using a diverse range of MRI images, has shown a notable level of sensitivity and specificity, significantly minimizing the frequency of false positive results and strengthening the confidence and dependability of these sophisticated automated diagnostic tools.
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Affiliation(s)
- J Satheesh Kumar
- Department of Electronics and Instrumentation Engineering, Dayananda Sagar College of Engineering, Bangalore, India
| | - V Vinoth Kumar
- School of Computer Science Engineering and Information Systems, Vellore Institute of Technology, Vellore, India
| | - T R Mahesh
- Department of Computer Science and Engineering, JAIN (Deemed-to-Be University), Bengaluru, 562112, India
| | - Mohammed S Alqahtani
- Radiological Sciences Department, College of Applied Medical Sciences, King Khalid University, 61421, Abha, Saudi Arabia
| | - P Prabhavathy
- School of Computer Science Engineering and Information Systems, Vellore Institute of Technology, Vellore, India
| | - K Manikandan
- School of Computer Science and Engineering (SCOPE), Vellore Institute of Technology (VIT), Vellore, India
| | - Suresh Guluwadi
- Adama Science and Technology University, 302120, Adama, Ethiopia.
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Kothandaraman K, Ganesan P, Nadig Ns V, Manikandan K. Prenatal diagnosis of fetal bradyarrhythmia and postnatal outcome. Indian Pacing Electrophysiol J 2024; 24:20-24. [PMID: 37838306 PMCID: PMC10928005 DOI: 10.1016/j.ipej.2023.10.003] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/31/2023] [Accepted: 10/09/2023] [Indexed: 10/16/2023] Open
Abstract
INTRODUCTION Prenatal diagnosis of Fetal bradyarrhythmia leads to parental and care provider anxiety as data on outcome is scarce. We aimed to correlate the prenatal presentation of fetal bradyarrhythmia with postnatal outcome. METHODS Retrospective analysis of case records from 2017 to 2021. All fetuses with sustained bradyarrhythmia beyond 11 weeks were included in the study. RESULTS Twenty fetuses were identified: mean gestational age at diagnosis was 23 weeks 2 days. The type of bradyarrhythmia was as follows: Complete atrioventricular block 10 (50 %), Sinus Bradycardia 7 (35 %), second degree atrioventricular block 2 (10 %), and Unclassified 1 (5 %). In 10 fetuses, cardiac and extracardiac anatomy were normal; 8 fetuses (40 %) had cardiac anomalies,1 fetus had intraventricular hemorrhage and 1 had nuchal cystic hygroma. Among the fetuses with associated anomalies, there were 5 terminations of pregnancy (TOP), 1 intrauterine fetal demise (IUD), 3 neonatal demise (NND) and 1 livebirth. Among fetuses with normal anatomy, there were 2 TOP and 8 livebirths; five of the 10 mothers (50 %) tested positive for Anti Ro/La antibodies. All the 6 liveborn fetuses with complete atrioventricular block are on conservative management: 2 on metaproterenol and 4 on clinical follow up. Nine out of the 10 cases that had a postnatal paediatric cardiology assessment had a correct prenatal diagnosis. CONCLUSION Correct prenatal identification of fetal bradyarrhythmia is feasible in about 90 % of cases. The risk of postnatal pacemaker requirement appears to be low irrespective of maternal Anti Ro/La status.
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Affiliation(s)
| | - Ponmozhi Ganesan
- The Fetal Clinic, No.8, Bajanai Madam Street, Ellaipillaichavady, Puducherry, 605005, India
| | - Vikram Nadig Ns
- The Fetal Clinic, No.8, Bajanai Madam Street, Ellaipillaichavady, Puducherry, 605005, India
| | - K Manikandan
- The Fetal Clinic, No.8, Bajanai Madam Street, Ellaipillaichavady, Puducherry, 605005, India.
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Pradeepa BR, Vijayakumar TM, Dhivya LS, Manikandan K. In-silico comparison of cytochrome P450 inhibitory and dopaminergic activity of Piperine, Curcumin and Capsaicin. Nat Prod Res 2023; 37:2888-2893. [PMID: 36255130 DOI: 10.1080/14786419.2022.2134862] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 09/14/2022] [Accepted: 10/04/2022] [Indexed: 10/24/2022]
Abstract
Psychiatric disorders are a heterogeneous group of mental disorders that manifest as abnormal mental or behavioral habits that cause the individual discomfort or disability. Dopamine imbalance plays a major role in many psychiatric disorders. Piperine, Curcumin and Capsaicin are CYP P450 3A4 & 2D6 inhibitors. The objective of this study is to determine the dopaminergic activity of Piperine, Curcumin and Capsaicin and also to compare cytochrome P450 3A4 and 2D6 inhibition activity by in-silico methods. In this in-silico study, we utilised compounds such as Piperine, Curcumin and Capsaicin were subjected to Lipinski's rule of five, and ligands were also evaluated for toxicity profile and ADMET properties. Furthermore, the ligands were performed in docking studies. All three compounds were docked with three different targeted proteins (PDB IDs: 4D7D, 4WNW and 6LUQ). According to the docking result, Piperine has higher binding energy(-8.55 kcal/mol)(-8.1 kcal/mol)(-8.57 kcal/mol) when compared with Curcumin(-7.39 kcal/mol)(-5.61 kcal/mol)(-6.57 kcal/mol) and Capsaicin (-6.86 kcal/mol)(-6.57 kcal/mol)(-5.42 kcal/mol) and also with standard drug (-8.61 kcal/mol)(-7.65 kcal/mol)(-6.16 kcal/mol). The present study concluded that the bioactive compound Piperine has a better inhibitory activity of CYP 3A4, 2D6 enzymes and dopamine D2 receptor among the three compounds and also with the standard drug thioridazine.
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Affiliation(s)
- B R Pradeepa
- Department of Pharmacy Practice, SRM College of Pharmacy, SRMIST, Kancheepuram, Tamil Nadu, India
| | - T M Vijayakumar
- Department of Pharmacy Practice, SRM College of Pharmacy, SRMIST, Kancheepuram, Tamil Nadu, India
| | - L S Dhivya
- Dr. APJ Abdul Kalam Research Lab, Department of Pharmaceutical Chemistry, SRM College of Pharmacy, SRMIST, Kancheepuram, Tamil Nadu, India
| | - K Manikandan
- Department of Pharmaceutical Analysis, SRM College of Pharmacy, SRMIST, Kancheepuram, Tamil Nadu, India
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Manikandan K, Sakkaravarthi K, Sudharsan JB, Aravinthan D. Deformation of optical solitons in a variable-coefficient nonlinear Schrödinger equation with three distinct PT-symmetric potentials and modulated nonlinearities. Chaos 2023; 33:2895997. [PMID: 37307166 DOI: 10.1063/5.0145283] [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: 02/04/2023] [Accepted: 05/22/2023] [Indexed: 06/14/2023]
Abstract
We investigate deformed/controllable characteristics of solitons in inhomogeneous parity-time (PT)-symmetric optical media. To explore this, we consider a variable-coefficient nonlinear Schrödinger equation involving modulated dispersion, nonlinearity, and tapering effect with PT-symmetric potential, which governs the dynamics of optical pulse/beam propagation in longitudinally inhomogeneous media. By incorporating three physically interesting and recently identified forms of PT-symmetric potentials, namely, rational, Jacobian periodic, and harmonic-Gaussian potentials, we construct explicit soliton solutions through similarity transformation. Importantly, we investigate the manipulation dynamics of such optical solitons due to diverse inhomogeneities in the medium by implementing step-like, periodic, and localized barrier/well-type nonlinearity modulations and revealing the underlying phenomena. Also, we corroborate the analytical results with direct numerical simulations. Our theoretical exploration will provide further impetus in engineering optical solitons and their experimental realization in nonlinear optics and other inhomogeneous physical systems.
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Affiliation(s)
- K Manikandan
- Center for Computational Modeling, Chennai Institute of Technology, Chennai 600069, Tamil Nadu, India
| | - K Sakkaravarthi
- Young Scientist Training Program, Asia-Pacific Center for Theoretical Physics (APCTP), POSTECH Campus, Pohang 37673, South Korea
| | - J B Sudharsan
- Center for Computational Modeling, Chennai Institute of Technology, Chennai 600069, Tamil Nadu, India
| | - D Aravinthan
- Center for Computational Modeling, Chennai Institute of Technology, Chennai 600069, Tamil Nadu, India
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Haridevamuthu B, Seenivasan B, Priya PS, Muthuraman S, Kumar RS, Manikandan K, Almutairi BO, Almutairi MH, Arokiyaraj S, Gopinath P, Arockiaraj J. Hepatoprotective effect of dihydroxy piperlongumine in high cholesterol-induced non-alcoholic fatty liver disease zebrafish via antioxidant activity. Eur J Pharmacol 2023; 945:175605. [PMID: 36822456 DOI: 10.1016/j.ejphar.2023.175605] [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: 11/16/2022] [Revised: 02/04/2023] [Accepted: 02/16/2023] [Indexed: 02/24/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are a growing epidemic and the most common liver diseases. Consumption of a western diet with high fats alters redox status, induces inflammation, and impairs the physiological function of hepatocytes. However, the pharmacological market lacks anti-NAFLD/NASH drugs. Long pepper (Piper longum L) is used in traditional Mongolian medicine for treating hyperlipidemia. Piperlongumine (PL) is a bioactive compound of Piper longum L, which usually possesses anticancer activities due to its ROS elevation property. However, when PL was demethylated they behave as an antioxidant. Previously, we found dihydroxy piperlongumine (DHPL) possesses high antioxidant activity among the hydroxy piperlongumines, which makes us curious to reveal the anti-NAFLD effect. A high-cholesterol diet (HCD) was chosen to induce NAFLD zebrafish model, and the antioxidant and lipid-lowering effects of DHPL were evaluated. Histological alterations of NAFLD were also scored along with gene expression to explore the molecular mechanism. DHPL reduced lipid accumulation in both short-term and long-term feeding trials. DHPL increases antioxidant activity and lipid-lowering gene expression and decreases hepatic triglyceride, oxidative stress, and lipogenic genes. In conclusion, DHPL halted the progression of HCD-induced NAFLD in the zebrafish model.
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Affiliation(s)
- B Haridevamuthu
- Department of Biotechnology, College of Science and Humanities, SRM Institute of Science and Technology, Kattankulathur, 603 203, Chennai, Tamil Nadu, India
| | - Boopathi Seenivasan
- Department of Biotechnology, College of Science and Humanities, SRM Institute of Science and Technology, Kattankulathur, 603 203, Chennai, Tamil Nadu, India
| | - P Snega Priya
- Department of Biotechnology, College of Science and Humanities, SRM Institute of Science and Technology, Kattankulathur, 603 203, Chennai, Tamil Nadu, India
| | - Subramani Muthuraman
- Chemistry Division, School of Advanced Sciences, VIT University Chennai Campus, Chennai, 600 127, Tamil Nadu, India
| | - Rajendran Saravana Kumar
- Chemistry Division, School of Advanced Sciences, VIT University Chennai Campus, Chennai, 600 127, Tamil Nadu, India
| | - K Manikandan
- Department of Pharmaceutical Analysis, SRM College of Pharmacy, SRM Institute of Science and Technology, Kattankulathur, 603 203, Chennai, Tamil Nadu, India
| | - Bader O Almutairi
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Riyadh, Saudi Arabia
| | - Mikhlid H Almutairi
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Riyadh, Saudi Arabia
| | - Selvaraj Arokiyaraj
- Department of Food Science & Biotechnology, Sejong University, Seoul, 05006, South Korea
| | - Pushparathinam Gopinath
- Department of Chemistry, College of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, 603 203, Chennai, Tamil Nadu, India.
| | - Jesu Arockiaraj
- Department of Biotechnology, College of Science and Humanities, SRM Institute of Science and Technology, Kattankulathur, 603 203, Chennai, Tamil Nadu, India.
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Vimala D, Manikandan K. PIRAP: Intelligent Hybrid Approach for Secure Data Transmission in Wireless Sensor Networks. INT J COOP INF SYST 2023. [DOI: 10.1142/s0218843023500028] [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: 01/12/2023]
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Chourasia AK, Pathak AD, Bongu C, Manikandan K, Praneeth S, Naik KM, Sharma CS. In Situ/Operando Characterization Techniques: The Guiding Tool for the Development of Li-CO 2 Battery. Small Methods 2022; 6:e2200930. [PMID: 36333232 DOI: 10.1002/smtd.202200930] [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: 07/16/2022] [Revised: 09/29/2022] [Indexed: 06/16/2023]
Abstract
In recent times, the Li-CO2 battery has gained significant importance arising from its higher gravimetric energy density (1876 Wh kg-1 ) compared to the conventional Li-ion batteries. Also, its ability to utilize the greenhouse gas CO2 to operate an energy storage system and the prospective utilization on extraterrestrial planets such as Mars motivate to practicalize it. However, it suffers from numerous challenges such as (i) the reluctant CO2 reduction/evolution; (ii) solid/liquid/gas interface blockage arising from the deposition of Li2 CO3 discharge product on the cathode; (iii) high overpotential to decompose the stable discharge product Li2 CO3 ; and (iv) instability of the electrolytes. Numerous efforts have been undertaken to tackle these challenges by developing catalysts, improving the stability of electrolytes, protecting the anode, etc. Despite these efforts, due to the lack of a decisive confirmation of the reaction mechanisms of the discharging/charging reactions occurring in the system, the progress of the Li-CO2 battery system has been slow. In situ characterization techniques help overcome ex-situ techniques' limitations by monitoring the processes with the progress of a reaction. The current review focuses on bridging the gap in the understanding of the Li-CO2 batteries by exploring the various in situ/operando characterization techniques that have been employed.
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Affiliation(s)
- Ankit K Chourasia
- Creative and Advanced Research Based On Nanomaterials (CARBON) Laboratory, Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502285, India
| | - Anil D Pathak
- Creative and Advanced Research Based On Nanomaterials (CARBON) Laboratory, Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502285, India
| | - Chandrasekhar Bongu
- Creative and Advanced Research Based On Nanomaterials (CARBON) Laboratory, Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502285, India
| | - K Manikandan
- Creative and Advanced Research Based On Nanomaterials (CARBON) Laboratory, Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502285, India
| | - Sai Praneeth
- Creative and Advanced Research Based On Nanomaterials (CARBON) Laboratory, Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502285, India
| | - Keerti M Naik
- Creative and Advanced Research Based On Nanomaterials (CARBON) Laboratory, Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502285, India
| | - Chandra S Sharma
- Creative and Advanced Research Based On Nanomaterials (CARBON) Laboratory, Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502285, India
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Thomas B, Manikandan K, Qurban M, Clardy T, Sundaramanickam A, Suarez-Morales E. First record of Caromiobenella helgolandica (Claus, 1863) (Copepoda, Monstrilloida) from the Saudi waters of the Arabian Gulf. CheckList 2022. [DOI: 10.15560/18.3.575] [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: 11/03/2022] Open
Abstract
Caromiobenella helgolandica (Claus, 1863), a presumedly widespread monstrilloid copepod, is reported for the first time from Saudi waters of the Arabian Gulf; only females were found in zooplankton samples collected from Tarut Bay in the Arabian Gulf. Caromiobenella Jeon, Lee, & Soh, 2018 is a recently described genus that is distinguished by having modified male antennules. The nauplii of monstrilloid copepods are endoparasitic on molluscs and polychaetes, while the adults are free-living reproductive forms. This study is an unprecedented record of C. helgolandica from the Arabian Gulf region.
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Meiyazhagan J, Manikandan K, Sudharsan JB, Senthilvelan M. Data driven soliton solution of the nonlinear Schrödinger equation with certain P T-symmetric potentials via deep learning. Chaos 2022; 32:053115. [PMID: 35649991 DOI: 10.1063/5.0086038] [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: 01/21/2022] [Accepted: 04/18/2022] [Indexed: 06/15/2023]
Abstract
We investigate the physics informed neural network method, a deep learning approach, to approximate soliton solution of the nonlinear Schrödinger equation with parity time symmetric potentials. We consider three different parity time symmetric potentials, namely, Gaussian, periodic, and Rosen-Morse potentials. We use the physics informed neural network to solve the considered nonlinear partial differential equation with the above three potentials. We compare the predicted result with the actual result and analyze the ability of deep learning in solving the considered partial differential equation. We check the ability of deep learning in approximating the soliton solution by taking the squared error between real and predicted values. Further, we examine the factors that affect the performance of the considered deep learning method with different activation functions, namely, ReLU, sigmoid, and tanh. We also use a new activation function, namely, sech, which is not used in the field of deep learning, and analyze whether this new activation function is suitable for the prediction of soliton solution of the nonlinear Schrödinger equation for the aforementioned parity time symmetric potentials. In addition to the above, we present how the network's structure and the size of the training data influence the performance of the physics informed neural network. Our results show that the constructed deep learning model successfully approximates the soliton solution of the considered equation with high accuracy.
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Affiliation(s)
- J Meiyazhagan
- Department of Nonlinear Dynamics, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India
| | - K Manikandan
- Centre for Nonlinear Systems, Chennai Institute of Technology, Chennai 600 069, Tamil Nadu, India
| | - J B Sudharsan
- Centre for Nonlinear Systems, Chennai Institute of Technology, Chennai 600 069, Tamil Nadu, India
| | - M Senthilvelan
- Department of Nonlinear Dynamics, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India
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Durairaj MS, Shaji Mathew J, Mallick S, Nair K, Manikandan K, Titus Varghese C, Chandran B, Amma BSPT, Balakrishnan D, Gopalakrishnan U, Menon RN, Vayoth SO, Surendran S. Middle hepatic vein reconstruction in adult living donor liver transplantation: a randomized clinical trial. Br J Surg 2021; 108:1426-1432. [PMID: 34849580 DOI: 10.1093/bjs/znab346] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/24/2021] [Accepted: 09/03/2021] [Indexed: 12/27/2022]
Abstract
BACKGROUND In adult right lobe living donor liver transplantation (LDLT), venous drainage of the anterior sector is usually reconstructed on the bench to form a neo-middle hepatic vein (MHV). Reconstruction of the MHV for drainage of the anterior sector is crucial for optimal graft function. The conduits used for reconstruction include cryopreserved allografts, synthetic grafts, or the recipient portal vein. However, the ideal choice remains a matter of debate. This study compares the efficacy of the native recipient portal vein (RPV) with PTFE grafts for reconstruction of the neo-MHV. METHODS Patients in this equivalence-controlled, parallel-group trial were randomized to either RPV (62 patients) or PTFE (60 patients) for use in the reconstruction of the neo-MHV. Primary endpoint was neo-MHV patency at 14 days and 90 days. Secondary outcomes included 90-day mortality and post-transplant parameters as scored by predefined scoring systems. RESULTS There was no statistically significant difference in the incidence of neo-MHV thrombosis at 14 days (RPV 6.5 per cent versus PTFE 10 per cent; P = 0.701) and 90 days (RPV 14.5 per cent versus PTFE 18.3 per cent; P = 0.745) between the two groups. Irrespective of the type of graft used for reconstruction, 90-day all-cause and sepsis-specific mortality was significantly higher among patients who developed neo-MHV thrombosis. Neo-MHV thrombosis and sepsis were identified as risk factors for mortality on Cox proportional hazards analysis. No harms or unintended side effects were observed in either group. CONCLUSION In adult LDLT using modified right lobe graft, use of either PTFE or RPV for neo-MHV reconstruction resulted in similar early patency rates. Irrespective of the type of conduit used for reconstruction, neo-MHV thrombosis is a significant risk factor for mortality. REGISTRATION NUMBER CTRI/2018/11/016315 (www.ctri.nic.in).
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Affiliation(s)
- Madhu Srinivasan Durairaj
- Department of Gastrointestinal Surgery & Solid Organ Transplant, Amrita Institute of Medical Sciences & Research Centre, Amrita University, Kochi, India
| | - Johns Shaji Mathew
- Department of Gastrointestinal Surgery & Solid Organ Transplant, Amrita Institute of Medical Sciences & Research Centre, Amrita University, Kochi, India
| | - Shweta Mallick
- Department of Gastrointestinal Surgery & Solid Organ Transplant, Amrita Institute of Medical Sciences & Research Centre, Amrita University, Kochi, India
| | - Krishnanunni Nair
- Department of Gastrointestinal Surgery & Solid Organ Transplant, Amrita Institute of Medical Sciences & Research Centre, Amrita University, Kochi, India
| | - K Manikandan
- Department of Gastrointestinal Surgery & Solid Organ Transplant, Amrita Institute of Medical Sciences & Research Centre, Amrita University, Kochi, India
| | - Christi Titus Varghese
- Department of Gastrointestinal Surgery & Solid Organ Transplant, Amrita Institute of Medical Sciences & Research Centre, Amrita University, Kochi, India
| | - Biju Chandran
- Department of Gastrointestinal Surgery & Solid Organ Transplant, Amrita Institute of Medical Sciences & Research Centre, Amrita University, Kochi, India
| | | | - Dinesh Balakrishnan
- Department of Gastrointestinal Surgery & Solid Organ Transplant, Amrita Institute of Medical Sciences & Research Centre, Amrita University, Kochi, India
| | - Unnikrishnan Gopalakrishnan
- Department of Gastrointestinal Surgery & Solid Organ Transplant, Amrita Institute of Medical Sciences & Research Centre, Amrita University, Kochi, India
| | - Ramachandran Narayana Menon
- Department of Gastrointestinal Surgery & Solid Organ Transplant, Amrita Institute of Medical Sciences & Research Centre, Amrita University, Kochi, India
| | - Sudheer Othiyil Vayoth
- Department of Gastrointestinal Surgery & Solid Organ Transplant, Amrita Institute of Medical Sciences & Research Centre, Amrita University, Kochi, India
| | - Sudhindran Surendran
- Department of Gastrointestinal Surgery & Solid Organ Transplant, Amrita Institute of Medical Sciences & Research Centre, Amrita University, Kochi, India
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Manikandan K, Chandra E. Speaker identification analysis for SGMM with k-means and fuzzy C-means clustering using SVM statistical technique. KES 2021. [DOI: 10.3233/kes-210073] [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: 11/15/2022]
Abstract
Speaker Identification denotes the speech samples of known speaker and it identifies the best matches of the input model. The SGMFC method is the combination of Sub Gaussian Mixture Model (SGMM) with the Mel-frequency Cepstral Coefficients (MFCC) for feature extraction. The SGMFC method minimizes the error rate, memory footprint and also computational throughput measure needs of a medium-vocabulary speaker identification system, supposed for preparation on a transportable or otherwise. Fuzzy C-means and k-means clustering are used in the SGMM method to attain the improved efficiency and their outcomes with parameters such as precision, sensitivity and specificity are compared.
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Affiliation(s)
- K. Manikandan
- Department of Computer Science, PSG College of Arts and Science, Coimbatore, India
| | - E. Chandra
- Department of Computer Science, Bharathiar University, Coimbatore, India
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Manikandan K, Kesavan MP, Thirugnanasundar A, Abdul Khader Jailani N, Jafar Ahamed A. Facile synthesis and characterization of W-doped TiO2 nanoparticles: Promising ancticancer activity with high selectivity. INORG CHEM COMMUN 2021. [DOI: 10.1016/j.inoche.2021.108855] [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: 12/31/2022]
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Manikandan K, Niveditha V. R., Sudha K., Magesh S., Radha Rammohan S.. Design and Development of Customer Relationship Management Recommendations by Clustering and Profiling of Customers Using RFM. International Journal of e-Collaboration 2021. [DOI: 10.4018/ijec.2021100108] [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] [Indexed: 11/09/2022]
Abstract
RFM (recency, frequency, monetary) examination is a method to perceive high-response customers in promoting progressions and to improve general response rates, which is remarkable and is comprehensively associated today. Less extensively understood is the estimation of applying RFM scoring to a customer database and evaluating customer advantage. A customer who has passed by an e-keeping cash site recently (R) and frequently (F) and influenced a huge amount of monetary to esteem (M) through portion and standing solicitations is presumably going to visit and make portions yet again. After appraisal of the customer's lead using specific RFM criteria, the RFM score is related to the bank excitement, with a high RFM score being more important to the bank by and by and later on.
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Affiliation(s)
| | | | - Sudha K.
- Dr. M. G. R. Educational and Research Institute, India
| | - Magesh S.
- Maruthi Technocrat E-Services, India
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Vimala D, Manikandan K. Grid Based Energy Efficient Routing Using Dual Mobile Sinks. Arab J Sci Eng 2021. [DOI: 10.1007/s13369-021-06134-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ponmozhi G, Lakshmanan A, Priya R, Manikandan K. Open Neural Tube Defect in a Fetus with MURCS Association: Value Addition of Fetal Autopsy in Counseling. J Fetal Med 2020. [DOI: 10.1007/s40556-020-00253-8] [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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Manikandan K, Pervin R, Saravanan C, Sathiskumar M, Chakraborty N, Shirage PM, Mondal S, Srihari V, Poswal HK, Arumugam S. Influence of pressure on the transport, magnetic, and structural properties of superconducting Cr 0.0009NbSe 2 single crystal. RSC Adv 2020; 10:13112-13125. [PMID: 35492110 PMCID: PMC9051428 DOI: 10.1039/c9ra09603e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/07/2020] [Indexed: 11/21/2022] Open
Abstract
We investigate the superconducting critical current density (J c), transition temperature (T c), and flux pinning properties under hydrostatic pressure (P) for Cr0.0009NbSe2 single crystal. The application of P enhances T c in both electrical resistivity (∼0.38 K GPa-1: 0 ≤ P ≤ 2.5 GPa) and magnetization (∼0.98 K GPa-1: 0 ≤ P ≤ 1 GPa) measurements, which leads to a monotonic increase in J c and flux pinning properties. The field-dependent J c at various temperatures under P is analyzed within the collecting pinning theory and it shows that δT c pinning is the crossover to δl pinning above the critical pressure (P c ∼0.3 GPa). Our systematic analysis of the flux pinning mechanism indicates that both the density of pinning centers and pinning forces greatly increase with the application of P, which leads to an enhancement in the vortex state. Structural studies using synchrotron X-ray diffraction under pressure illustrate a stable hexagonal phase without any significant impurity phase and lattice parameter reduction with P shows highly anisotropic nature.
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Affiliation(s)
- K Manikandan
- Centre for High Pressure Research, School of Physics, Bharathidasan University Tiruchirappalli-620024 India +91 431 2407045 +91 431 2407118 +91 9500910310
| | - Rukshana Pervin
- Discipline of Metallurgy Engineering and Materials Science & Physics, Indian Institute of Technology Indore Simrol Campus, Khandwa Road Indore 453552 India
| | - C Saravanan
- Centre for High Pressure Research, School of Physics, Bharathidasan University Tiruchirappalli-620024 India +91 431 2407045 +91 431 2407118 +91 9500910310
| | - M Sathiskumar
- Centre for High Pressure Research, School of Physics, Bharathidasan University Tiruchirappalli-620024 India +91 431 2407045 +91 431 2407118 +91 9500910310
| | - Nirman Chakraborty
- CSIR-Central Glass and Ceramic Research Institute Jadavpur Kolkata 700 032 India
| | - Parasharam M Shirage
- Discipline of Metallurgy Engineering and Materials Science & Physics, Indian Institute of Technology Indore Simrol Campus, Khandwa Road Indore 453552 India
| | - Swastik Mondal
- CSIR-Central Glass and Ceramic Research Institute Jadavpur Kolkata 700 032 India
| | - Velaga Srihari
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre Mumbai 400085 India
| | - Himanshu Kumar Poswal
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre Mumbai 400085 India
| | - S Arumugam
- Centre for High Pressure Research, School of Physics, Bharathidasan University Tiruchirappalli-620024 India +91 431 2407045 +91 431 2407118 +91 9500910310
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Ponmozhi G, Keepanasseril A, Mathaiyan J, Manikandan K. Nitric Oxide in the Prevention of Pre-eclampsia (NOPE): A Double-Blind Randomized Placebo-Controlled Trial Assessing the Efficacy of Isosorbide Mononitrate in the Prevention of Pre-eclampsia in High-Risk Women. J Obstet Gynaecol India 2019; 69:103-110. [PMID: 31686742 PMCID: PMC6801247 DOI: 10.1007/s13224-018-1100-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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: 05/31/2017] [Accepted: 02/22/2018] [Indexed: 10/17/2022] Open
Abstract
INTRODUCTION Pre-eclampsia contributes to maternal and fetal morbidity and mortality all over the world. Endothelial dysfunction is postulated to be the crux of the pathogenesis. Recent meta-analysis of aspirin trials showed aspirin to be effective when started early in pregnancy (at ≤ 16-week gestation). We aimed to study the effect of low-dose prophylactic isosorbide mononitrate (ISMN) 20 mg/day on the incidence of hypertensive diseases in high-risk women receiving standard aspirin prophylaxis. METHODS Design: Randomized double-blind placebo-controlled parallel-arm superiority trial. Setting: Antenatal clinic of a tertiary teaching hospital, South India. Participants and methods: One hundred women fulfilling NICE guideline criteria for aspirin prophylaxis recruited at 12-16 weeks were randomized to receive either 20 mg/day of ISMN or placebo, in addition to 75 mg/day of oral aspirin from recruitment till delivery. Main outcome measure: Rate of hypertensive disorder of pregnancy (HDP). Sample Size: One hundred women (50 in each arm) to detect a decrease of HDP from 20% in the placebo group to 5% in the ISMN group with a power of 80% and at 0.05. RESULTS One hundred women (50 in each arm) participated and completed the trial. Intention to treat analysis of these 100 women showed that the groups were comparable in terms of age, BMI, parity, and vascular indices (such as mean arterial pressure, uterine artery pulsatility index, flow-mediated vasodilatation index, brachial-ankle pulse wave velocity, Ankle-Brachial Index, brachial arterial stiffness index, and ankle arterial stiffness index). The rate of hypertensive disorders (gestational hypertension, pre-eclampsia, or superimposed pre-eclampsia) was not significantly different between the groups (14/50, 28% in ISMN vs. 12/50, 24% in placebo group; p = 0.7). The mean gestational age at diagnosis of hypertensive disease (35.4 vs. 36 weeks, ISMN vs. placebo groups, p = 0.7) or the rate of severe disease (8/50, 16% in ISMN vs. 7/50, 14% in the placebo group; p = 0.9) did not differ significantly between the two groups. Stillbirths (1 vs. 2), NICU admission rates (18 vs. 10%), and neonatal mortality (2 vs. 2) were also similar between the groups. CONCLUSION The results of the randomized controlled trial of nitric oxide in the prevention of pre-eclampsia (NOPE) showed that in high-risk women receiving standard aspirin prophylaxis from less than 16 weeks, there is no significant reduction in the incidence of hypertensive disorders of pregnancy in the ISMN group, to the desired extent. There was no significant effect on the severity of disease, gestational age at diagnosis of disease or maternal-perinatal morbidity due to low-dose isosorbide mononitrate.
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Affiliation(s)
- G. Ponmozhi
- Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
| | - Anish Keepanasseril
- Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
| | - Jayanthi Mathaiyan
- Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
| | - K. Manikandan
- Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
- Fetal Care Research Foundation and Mediscan Systems, Chennai, 197, Dr Natesan Road, Mylapore, Chennai 600004 India
- The Fetal Clinic, Pondicherry, India
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Hassan AT, Qurban M, Manikandan K, Tawabini B, Basheer C, Periyadan K. Assessment of the organotin pollution in the coastal sediments of the Western Arabian Gulf, Saudi Arabia. Mar Pollut Bull 2019; 139:174-180. [PMID: 30686416 DOI: 10.1016/j.marpolbul.2018.12.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [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: 08/22/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 06/09/2023]
Abstract
Organotin compounds (OTCs) are persistent pollutants and are considered as chemicals of environmental concern. They enter the marine environment from the antifouling paints containing organotin compounds on the hulls of ships and boats. We report the results of a study conducted in 2015 on the level of butyltins (TBT, DBT, and MBT) and phenyltins (TPhT, DPhT, and MPhT) in the sediments collected from three fishing harbors (Jubail, Khobar, and Qatif) and a reference site (Half Moon Bay). The concentrations of OTCs in the sediments vary widely among the different sampling locations. Overall, the phenyltins contribute more than the butyltins and the order of the abundance is: MPhT > DPhT > MBT > DBT > TPhT. In most stations, the concentrations of MBT are higher than DBT. The sediments from Khobar and Qatif are moderately polluted, whereas those from the Jubail are ranked as highly polluted. The concentrations of TBT at all study sites are less than the detection limit, and hence, the environmental and ecotoxicological risks are low.
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Affiliation(s)
- Akere Taiwo Hassan
- College of Petroleum Engineering & Geosciences, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia
| | - Mohammed Qurban
- College of Petroleum Engineering & Geosciences, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia.
| | - Karuppasamy Manikandan
- Center for Environment & Water, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia.
| | - Bassam Tawabini
- College of Petroleum Engineering & Geosciences, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia.
| | - Chanbasha Basheer
- College of Petroleum Engineering & Geosciences, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia.
| | - Krishnakumar Periyadan
- Center for Environment & Water, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia.
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Sundarrajan T, Velmurugan V, Manikandan K, Jothieswari D. A study of In-vitro hypoglycemic and glucose uptake activity of isolated compound from ethanolic leaf extract of Amaranthus tristis Linn. Pharmacognosy Res 2019. [DOI: 10.4103/pr.pr_119_18] [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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Manikandan K, Vishnu Priya N, Senthilvelan M, Sankaranarayanan R. Deformation of dark solitons in a PT -invariant variable coefficients nonlocal nonlinear Schrödinger equation. Chaos 2018; 28:083103. [PMID: 30180644 DOI: 10.1063/1.5039901] [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: 05/12/2018] [Accepted: 06/26/2018] [Indexed: 06/08/2023]
Abstract
We derive dark and antidark soliton solutions of a parity-time reversal (PT) -invariant variable coefficients nonlocal nonlinear Schrödinger (NNLS) equation. We map the considered equation into a defocusing PT -invariant NNLS equation with a constraint between dispersion, nonlinearity, and gain/loss parameters. We show that the considered system is PT -invariant only when the dispersion and nonlinearity coefficients are even functions and gain/loss coefficient is an odd function. The characteristics of the constructed dark soliton solutions are investigated with four different forms of dispersion parameters, namely, (1) constant, (2) periodically distributed, (3) exponentially distributed, and (4) periodically and exponentially distributed dispersion parameter. We analyze in detail how the nonlocal dark soliton profiles get deformed in the plane wave background with these dispersion parameters.
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Affiliation(s)
- K Manikandan
- Department of Physics, National Institute of Technology, Tiruchirappalli 620015, Tamil Nadu, India
| | - N Vishnu Priya
- Department of Mathematics, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - M Senthilvelan
- Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India
| | - R Sankaranarayanan
- Department of Physics, National Institute of Technology, Tiruchirappalli 620015, Tamil Nadu, India
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Shamsudeen SM, Priya RS, Sujatha G, Muruganandhan J, Manikandan K. Self-medication with antibiotics: A knowledge, attitude, and practice appraisal of 610 dental patients in Chennai, India, from 2016 to 2017. J Educ Health Promot 2018; 7:66. [PMID: 29922695 PMCID: PMC5963215 DOI: 10.4103/jehp.jehp_143_17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/09/2018] [Indexed: 06/08/2023]
Abstract
INTRODUCTION Antibiotics are considered the most commonly sold drugs in developing countries. In India, these drugs are very much accessible without a prescription. This irrational and misuse of antibiotics results not only in the emergence of resistance of bacterial strains but also leads to adverse reactions. AIM The aim of this study was to investigate the level of knowledge, attitude, and practice of antibiotics usage among dental patients. MATERIALS AND METHODS Study design: This study was a cross-sectional design; a prevalidated structured questionnaire comprising 24 questions was used. SAMPLE SIZE Six hundred and ten patients visiting a dental hospital, Chennai, Tamil Nadu, India, were included in the study. RESULTS The dental patients involved in self-medication were more than 70%. 80.2% of the study group opted selection of antibiotics from their previous prescription from dental or medical professional. Adverse effects were faced by 7.8% of patients on taking self-medication. The study group was aware of the common dental procedures such as extraction and root canal treatment in which antibiotics were commonly prescribed. Half of the patients (53.8%) do not know the term antibiotic misuse, and 43.3% of the group opted antibiotic misuse to be unacceptable. CONCLUSION The study revealed the knowledge, attitude, and practice of the patients about self-medication in the Indian scenario. There is need for health-care professionals and government bodies to enlighten the public about the harmful effects of self-medication with antibiotics to overcome the antibiotic resistance.
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Affiliation(s)
- Shaik Mohamed Shamsudeen
- Department of Oral Pathology, Sri Venkateswara Dental College and Hospital, Chennai, Tamil Nadu, India
| | - R. Shanmuga Priya
- Department of Periodontia, Sri Venkateswara Dental College and Hospital, Chennai, Tamil Nadu, India
| | - Govindarajan Sujatha
- Department of Oral Pathology, Sri Venkateswara Dental College and Hospital, Chennai, Tamil Nadu, India
| | - J. Muruganandhan
- Department of Oral Pathology, Sri Venkateswara Dental College and Hospital, Chennai, Tamil Nadu, India
| | - K. Manikandan
- Department of Public Health Dentistry, Sri Venkateswara Dental College and Hospital, Chennai, Tamil Nadu, India
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Manikandan K, Ponmozhi G, Keepanasseril A, Jayanthi M. 318: Endothelial function is unaltered by prophylactic nitric oxide donor in women at high-risk for preeclampsia. Am J Obstet Gynecol 2018. [DOI: 10.1016/j.ajog.2017.10.254] [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: 10/18/2022]
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Dhandayuthapani T, Girish M, Sivakumar R, Sanjeeviraja C, Gopalakrishnan C, Nagarajan RS, Mathew S, Jun D, Venkatesan T, Kalai Selvan G, Manikandan K, Arumugam S. γ-MnS films with 3D microarchitectures: comprehensive study of the synthesis, microstructural, optical and magnetic properties. CrystEngComm 2018. [DOI: 10.1039/c7ce01536d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A simple procedure to synthesize 3D microarchitectures of γ-MnS films at low temperature is described in the present work.
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Keepanasseril A, Maurya DK, Manikandan K, Suriya J Y, Habeebullah S, Raghavan SS. Prophylactic magnesium sulphate in prevention of eclampsia in women with severe preeclampsia: randomised controlled trial (PIPES trial). J OBSTET GYNAECOL 2017; 38:305-309. [DOI: 10.1080/01443615.2017.1351931] [Citation(s) in RCA: 7] [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] [Indexed: 10/18/2022]
Affiliation(s)
- Anish Keepanasseril
- Department of Obstetrics and Gynecology, Jawaharlal Institute of Post-graduate Medical Education and Research, Puducherry, India
| | - Dilip Kumar Maurya
- Department of Obstetrics and Gynecology, Jawaharlal Institute of Post-graduate Medical Education and Research, Puducherry, India
| | - K. Manikandan
- Department of Obstetrics and Gynecology, Jawaharlal Institute of Post-graduate Medical Education and Research, Puducherry, India
| | - Yavana Suriya J
- Department of Obstetrics and Gynecology, Jawaharlal Institute of Post-graduate Medical Education and Research, Puducherry, India
| | - Syed Habeebullah
- Department of Obstetrics and Gynecology, Jawaharlal Institute of Post-graduate Medical Education and Research, Puducherry, India
| | - S. Soundara Raghavan
- Department of Obstetrics and Gynecology, Jawaharlal Institute of Post-graduate Medical Education and Research, Puducherry, India
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Arumugam S, Ganguli C, Thiyagarajan R, Bhoi D, Selvan GK, Manikandan K, Pariari A, Mandal P, Uwatoko Y. Effect of pressure on normal and superconducting state properties of iron based superconductor PrFeAsO 0.6F y (y = 0.12, 0.14). Sci Rep 2017; 7:11731. [PMID: 28916795 PMCID: PMC5601470 DOI: 10.1038/s41598-017-11927-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 08/30/2017] [Indexed: 11/09/2022] Open
Abstract
The effect of high pressure (up to 8 GPa) on normal and superconducting state properties of PrFeAsO0.6F0.12, an 1111-type iron based superconductor close to optimal doped region, has been investigated by measuring the temperature dependence of resistivity. Initially, the superconducting transition temperature (T c ) is observed to increase slowly by about 1 K as pressure (P) increases from 0 to 1.3 GPa. With further increase in pressure above 1.3 GPa, T c decreases at the rate of ~1.5 K/GPa. The normal-state resistivity decreases monotonically up to 8 GPa. We have also measured the pressure dependence of magnetization (M) on the same piece of PrFeAsO0.6F0.12 sample up to 1.1 GPa and observed T c as well as the size of the Meissner signal to increase with pressure in this low-pressure region. In contrast, for an over-doped PrFeAsO0.6F0.14 sample, magnetization measurements up to 1.06 GPa show that both T c and the Meissner signal decrease with pressure. The present study clearly reveals two distinct regions in the dome-shaped (T c -P) phase diagram of PrFeAsO0.6F0.12.
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Affiliation(s)
- S Arumugam
- Centre for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirappalli, 620 024, India.
| | - C Ganguli
- ISSP, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8581, Japan
| | - R Thiyagarajan
- Centre for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirappalli, 620 024, India
| | - D Bhoi
- Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhannagar, Calcutta, 700 064, India
| | - G Kalai Selvan
- Centre for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirappalli, 620 024, India
| | - K Manikandan
- Centre for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirappalli, 620 024, India
| | - A Pariari
- Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhannagar, Calcutta, 700 064, India
| | - P Mandal
- Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhannagar, Calcutta, 700 064, India.
| | - Y Uwatoko
- ISSP, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8581, Japan
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Venkatachalam P, Priyanka N, Manikandan K, Ganeshbabu I, Indiraarulselvi P, Geetha N, Muralikrishna K, Bhattacharya RC, Tiwari M, Sharma N, Sahi SV. Enhanced plant growth promoting role of phycomolecules coated zinc oxide nanoparticles with P supplementation in cotton (Gossypium hirsutum L.). Plant Physiol Biochem 2017; 110:118-127. [PMID: 27622847 DOI: 10.1016/j.plaphy.2016.09.004] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [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: 04/03/2016] [Revised: 07/24/2016] [Accepted: 09/03/2016] [Indexed: 05/21/2023]
Abstract
This report focuses on application of zinc oxide nanoparticles (ZnONPs) carrying phycomolecule ligands as a novel plant growth promoter aimed at increasing the crop productivity. The present investigation examined the effect of ZnONPs on plant growth characteristics, and associated biochemical changes in cotton (Gossypium hirsutum L.) following growth in a range of concentrations (25-200 mg L-l ZnONPs) in combination with 100 mM P in a hydroponic system. Treated plants registered an increase in growth and total biomass by 130.6% and 131%, respectively, over control. Results demonstrated a significant increase in the level of chlorophyll a (141.6%), b (134.7%), carotenoids (138.6%), and total soluble protein contents (179.4%); at the same time, a significant reduction (68%) in the level of malondialdehyde (MDA) in leaves with respect to control. Interestingly, a significant increase in superoxide dismutase (SOD, 264.2%), and peroxidase (POX, 182.8%) enzyme activities followed by a decrease in the catalase (CAT) activity, in response to above treatments. These results suggest that bioengineered ZnONPs interact with meristematic cells triggering biochemical pathways conducive to an accumulation of biomass. Further investigations will map out the mode of action involved in growth promotion.
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Affiliation(s)
- P Venkatachalam
- Department of Biotechnology, Periyar University, Periyar Palkalai Nagar, Salem, 636 011, Tamil Nadu, India.
| | - N Priyanka
- Department of Biotechnology, Periyar University, Periyar Palkalai Nagar, Salem, 636 011, Tamil Nadu, India
| | - K Manikandan
- Department of Biotechnology, Periyar University, Periyar Palkalai Nagar, Salem, 636 011, Tamil Nadu, India
| | - I Ganeshbabu
- Department of Biotechnology, Periyar University, Periyar Palkalai Nagar, Salem, 636 011, Tamil Nadu, India
| | - P Indiraarulselvi
- Department of Biotechnology, Periyar University, Periyar Palkalai Nagar, Salem, 636 011, Tamil Nadu, India
| | - N Geetha
- Department of Biotechnology, Mother Teresa Women's University, Kodaikanal, 624 102, Tamil Nadu, India
| | - K Muralikrishna
- National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute, Pusa Campus, New Delhi, 110 012, India
| | - R C Bhattacharya
- National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute, Pusa Campus, New Delhi, 110 012, India
| | - M Tiwari
- Department of Biology, Western Kentucky University, Bowling Green, KY, 42101, USA
| | - N Sharma
- Department of Biology, Western Kentucky University, Bowling Green, KY, 42101, USA
| | - S V Sahi
- Department of Biology, Western Kentucky University, Bowling Green, KY, 42101, USA
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Manikandan K, Senthilvelan M. An analysis of spatiotemporal localized solutions in the variable coefficients (3 + 1)-dimensional nonlinear Schrödinger equation with six different forms of dispersion parameters. Chaos 2016; 26:073116. [PMID: 27475076 DOI: 10.1063/1.4959145] [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] [Indexed: 06/06/2023]
Abstract
We construct spatiotemporal localized envelope solutions of a (3 + 1)-dimensional nonlinear Schrödinger equation with varying coefficients such as dispersion, nonlinearity and gain parameters through similarity transformation technique. The obtained localized rational solutions can serve as prototypes of rogue waves in different branches of science. We investigate the characteristics of constructed localized solutions in detail when it propagates through six different dispersion profiles, namely, constant, linear, Gaussian, hyperbolic, logarithm, and exponential. We also obtain expressions for the hump and valleys of rogue wave intensity profiles for these six dispersion profiles and study the trajectory of it in each case. Further, we analyze how the intensity of another localized solution, namely, breather, changes when it propagates through the aforementioned six dispersion profiles. Our studies reveal that these localized solutions co-exist with the collapsing solutions which are already found in the (3 + 1)-dimensional nonlinear Schrödinger equation. The obtained results will help to understand the corresponding localized wave phenomena in related fields.
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Affiliation(s)
- K Manikandan
- Centre for Nonlinear Dynamics, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu, India
| | - M Senthilvelan
- Centre for Nonlinear Dynamics, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu, India
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Manikandan K, Muruganandam P, Senthilvelan M, Lakshmanan M. Manipulating localized matter waves in multicomponent Bose-Einstein condensates. Phys Rev E 2016; 93:032212. [PMID: 27078349 DOI: 10.1103/physreve.93.032212] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Indexed: 11/07/2022]
Abstract
We analyze vector localized solutions of two-component Bose-Einstein condensates (BECs) with variable nonlinearity parameters and external trap potentials through a similarity transformation technique which transforms the two coupled Gross-Pitaevskii equations into a pair of coupled nonlinear Schrödinger equations with constant coefficients under a specific integrability condition. In this analysis we consider three different types of external trap potentials: a time-independent trap, a time-dependent monotonic trap, and a time-dependent periodic trap. We point out the existence of different interesting localized structures; namely, rogue waves, dark- and bright-soliton rogue waves, and rogue-wave breatherlike structures for the above three cases of trap potentials. We show how the vector localized density profiles in a constant background get deformed when we tune the strength of the trap parameter. Furthermore, we investigate the nature of the trajectories of the nonautonomous rogue waves. We also construct the dark-dark rogue wave solution for the repulsive-repulsive interaction of two-component BECs and analyze the associated characteristics for the three different kinds of traps. We then deduce single-, two-, and three-composite rogue waves for three-component BECs and discuss the correlated characteristics when we tune the strength of the trap parameter for different trap potentials.
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Affiliation(s)
- K Manikandan
- Centre for Nonlinear Dynamics, Bharathidasan University, Tiruchirappalli 620024, Tamilnadu, India
| | - P Muruganandam
- Department of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamilnadu, India
| | - M Senthilvelan
- Centre for Nonlinear Dynamics, Bharathidasan University, Tiruchirappalli 620024, Tamilnadu, India
| | - M Lakshmanan
- Centre for Nonlinear Dynamics, Bharathidasan University, Tiruchirappalli 620024, Tamilnadu, India
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Manikandan K, Dhanuskodi S, Thomas AR, Maheswari N, Muralidharan G, Sastikumar D. Size–strain distribution analysis of SnO2 nanoparticles and their multifunctional applications as fiber optic gas sensors, supercapacitors and optical limiters. RSC Adv 2016. [DOI: 10.1039/c6ra20503h] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SnO2 nanoparticles (NPs) were prepared by a wet chemical method and characterized by X-ray diffraction (XRD) (rutile tetragonal), Fourier transform infrared spectroscopy (FTIR) (Sn–O, 657 cm−1) and micro Raman spectroscopy (Sn–O, 635 cm−1).
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Affiliation(s)
- K. Manikandan
- Nonlinear Optical Materials Laboratory
- School of Physics
- Bharathidasan University
- Tiruchirappalli-620 024
- India
| | - S. Dhanuskodi
- Nonlinear Optical Materials Laboratory
- School of Physics
- Bharathidasan University
- Tiruchirappalli-620 024
- India
| | - Anitta Rose Thomas
- Light and Matter Physics Group
- Raman Research Institute
- Bangalore-560 080
- India
| | - N. Maheswari
- Department of Physics
- Gandhigram Rural Institute-Deemed University
- Dindigul-624 302
- India
| | - G. Muralidharan
- Department of Physics
- Gandhigram Rural Institute-Deemed University
- Dindigul-624 302
- India
| | - D. Sastikumar
- Department of Physics
- National Institute of Technology
- Tiruchirappalli-620 015
- India
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30
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Manikandan K, Dilip CS, Mani P, Prince JJ. Deposition and Characterization of CdS Nano Thin Film with Complexing Agent Triethanolamine. ACTA ACUST UNITED AC 2015. [DOI: 10.3844/ajeassp.2015.318.327] [Citation(s) in RCA: 21] [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: 11/13/2022]
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31
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Manikandan K, Muruganandam P, Senthilvelan M, Lakshmanan M. Manipulating matter rogue waves and breathers in Bose-Einstein condensates. Phys Rev E Stat Nonlin Soft Matter Phys 2014; 90:062905. [PMID: 25615162 DOI: 10.1103/physreve.90.062905] [Citation(s) in RCA: 1] [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: 07/02/2014] [Indexed: 06/04/2023]
Abstract
We construct higher-order rogue wave solutions and breather profiles for the quasi-one-dimensional Gross-Pitaevskii equation with a time-dependent interatomic interaction and external trap through the similarity transformation technique. We consider three different forms of traps: (i) the time-independent expulsive trap, (ii) time-dependent monotonous trap, and (iii) time-dependent periodic trap. Our results show that when we change a parameter appearing in the time-independent or time-dependent trap the second- and third-order rogue waves transform into the first-order-like rogue waves. We also analyze the density profiles of breather solutions. Here we also show that the shapes of the breathers change when we tune the strength of the trap parameter. Our results may help to manage rogue waves experimentally in a BEC system.
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Affiliation(s)
- K Manikandan
- Centre for Nonlinear Dynamics, Bharathidasan University, Tiruchirappalli 620024, Tamilnadu, India
| | - P Muruganandam
- Department of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamilnadu, India
| | - M Senthilvelan
- Centre for Nonlinear Dynamics, Bharathidasan University, Tiruchirappalli 620024, Tamilnadu, India
| | - M Lakshmanan
- Centre for Nonlinear Dynamics, Bharathidasan University, Tiruchirappalli 620024, Tamilnadu, India
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33
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Manikandan K, Raghavan S. Amniotic fluid volume changes in response to frusemide induced maternal fluid shifts. J Pharmacol Pharmacother 2014; 5:153-4. [PMID: 24799818 PMCID: PMC4008913 DOI: 10.4103/0976-500x.130075] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 05/29/2013] [Accepted: 06/16/2013] [Indexed: 12/04/2022] Open
Abstract
Frusemide use in pregnancy is generally restricted to patients with cardiac decompensation. In the past, maternal administration of oral frusemide had been tried to identify non-functioning fetal kidneys by utilizing the diuretic effect of frusemide on the fetal kidneys. We report a case of primigravida with severe mitral stenosis presenting in pulmonary edema that received high dose of frusemide. This was associated with the development of transient oligohydramnios. We discuss the clinical significance of this observation and the possible explanations.
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Affiliation(s)
- K Manikandan
- Department of Obstetrics and Gynaecology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - S Raghavan
- Department of Obstetrics and Gynaecology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
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Manikandan K, Dasari P, Sagili H. Third-Trimester Uterine Rupture Following Hysteroscopic Septoplasty: The Need for Standardization of Indications. J Gynecol Surg 2014. [DOI: 10.1089/gyn.2013.0033] [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: 11/13/2022] Open
Affiliation(s)
- K Manikandan
- Department of Obstetrics and Gynecology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Papa Dasari
- Department of Obstetrics and Gynecology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Haritha Sagili
- Department of Obstetrics and Gynecology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
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Sagili H, Singh P, Manikandan K, Dasari P. Vaginal delivery after augmentation cystoplasty and Mitrofanoff's procedure for incontinence following traumatic bladder neck transection. J OBSTET GYNAECOL 2013; 33:740-1. [DOI: 10.3109/01443615.2013.817385] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Abstract
Malignancy complicating pregnancy represents one of the most challenging clinical situations. Lack of evidence and the presence of the dependent fetus contribute to the management dilemma. A 26-year-old primigravida presented at 23 weeks of gestation with a bulging substernal mass. Fine-needle aspiration was reported as mediastinal dysgerminoma. She was treated with weekly bleomycin and three weekly cisplatin and etoposide (BEP). Maternal neutropenia after 11 weeks of bleomycin required colony stimulator factor. Fetal growth restriction necessitated delivery at 31 weeks. Significant clinical and radiological tumour regression was noted after chemotherapy. Postnatally mother received external beam radiotherapy but the disease worsened two weeks after the completion of radiotherapy. Mediastinal dysgerminoma differs from the ovarian counterpart and therefore therapeutic success reports on ovarian germ cell tumours complicating pregnancy cannot be extrapolated. The safety of the BEP regimen for the fetus is yet to be established.
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Affiliation(s)
- K Manikandan
- Jawaharlal Institute of Postgraduate Medical Education and Research - Obstetrics and Gynaecology , Dhanvantari Nagar, Puducherry 605006 , India
| | - P Veena
- Jawaharlal Institute of Postgraduate Medical Education and Research - Obstetrics and Gynaecology , Dhanvantari Nagar, Puducherry 605006 , India
| | - S Elamurugan
- Jawaharlal Institute of Postgraduate Medical Education and Research - Obstetrics and Gynaecology , Dhanvantari Nagar, Puducherry 605006 , India
| | - S Soundararaghavan
- Jawaharlal Institute of Postgraduate Medical Education and Research - Obstetrics and Gynaecology , Dhanvantari Nagar, Puducherry 605006 , India
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Manikandan K, Geerlof A, Zozulya AV, Svergun DI, Weiss MS. Structural studies on the enzyme complex isopropylmalate isomerase (LeuCD) fromMycobacterium tuberculosis. Proteins 2010; 79:35-49. [DOI: 10.1002/prot.22856] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 07/08/2010] [Accepted: 07/25/2010] [Indexed: 11/10/2022]
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Merli A, Manikandan K, Gráczer É, Schuldt L, Singh RK, Závodszky P, Vas M, Weiss MS. Crystallization and preliminary X-ray diffraction analysis of various enzyme-substrate complexes of isopropylmalate dehydrogenase from Thermus thermophilus. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:738-43. [PMID: 20516614 PMCID: PMC2882784 DOI: 10.1107/s174430911001626x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 04/16/2010] [Accepted: 05/03/2010] [Indexed: 11/10/2022]
Abstract
The Thermus thermophilus 3-isopropylmalate dehydrogenase (Tt-IPMDH) enzyme catalyses the penultimate step of the leucine-biosynthesis pathway. It converts (2R,3S)-3-isopropylmalate to (2S)-2-isopropyl-3-oxosuccinate in the presence of divalent Mg(2+) or Mn(2+) and with the help of NAD(+). In order to elucidate the detailed structural and functional mode of the enzymatic reaction, crystals of Tt-IPMDH were grown in the presence of various combinations of substrate and/or cofactors. Here, the crystallization, data collection and preliminary crystallographic analyses of six such complexes are reported.
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Affiliation(s)
- Angelo Merli
- Department of Biochemistry and Molecular Biology, University of Parma, Viale G. P. Usberti 23/A, 43100 Parma, Italy
| | | | - Éva Gráczer
- Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, H1518 Budapest, PO Box 7, Hungary
| | - Linda Schuldt
- EMBL Hamburg Outstation, c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
| | | | - Péter Závodszky
- Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, H1518 Budapest, PO Box 7, Hungary
| | - Mária Vas
- Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, H1518 Budapest, PO Box 7, Hungary
| | - Manfred S. Weiss
- EMBL Hamburg Outstation, c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
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Sivasubramanian L, Manikandan K, Venkatesan M, Lakshmi KS. Quantitative analysis of manidipine dihydrochloride in bulk and synthetic mixtures by visible spectrophotometry. J Young Pharm 2009. [DOI: 10.4103/0975-1483.55752] [Citation(s) in RCA: 2] [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: 11/04/2022] Open
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Manikandan K, Pal D, Ramakumar S, Brener NE, Iyengar SS, Seetharaman G. Functionally important segments in proteins dissected using Gene Ontology and geometric clustering of peptide fragments. Genome Biol 2008; 9:R52. [PMID: 18331637 PMCID: PMC2397504 DOI: 10.1186/gb-2008-9-3-r52] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 02/24/2008] [Accepted: 03/10/2008] [Indexed: 11/25/2022] Open
Abstract
A geometric clustering algorithm has been developed to dissect protein fragments based on their relevance to function. We have developed a geometric clustering algorithm using backbone φ,ψ angles to group conformationally similar peptide fragments of any length. By labeling each fragment in the cluster with the level-specific Gene Ontology 'molecular function' term of its protein, we are able to compute statistics for molecular function-propensity and p-value of individual fragments in the cluster. Clustering-cum-statistical analysis for peptide fragments 8 residues in length and with only trans peptide bonds shows that molecular function propensities ≥20 and p-values ≤0.05 can dissect fragments within a protein linked to the molecular function.
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Manikandan K, Bhardwaj A, Gupta N, Lokanath NK, Ghosh A, Reddy VS, Ramakumar S. Crystal structures of native and xylosaccharide-bound alkali thermostable xylanase from an alkalophilic Bacillus sp. NG-27: structural insights into alkalophilicity and implications for adaptation to polyextreme conditions. Protein Sci 2006; 15:1951-60. [PMID: 16823036 PMCID: PMC2242578 DOI: 10.1110/ps.062220206] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Crystal structures are known for several glycosyl hydrolase family 10 (GH10) xylanases. However, none of them is from an alkalophilic organism that can grow in alkaline conditions. We have determined the crystal structures at 2.2 Angstroms of a GH10 extracellular endoxylanase (BSX) from an alkalophilic Bacillus sp. NG-27, for the native and the complex enzyme with xylosaccharides. The industrially important enzyme is optimally active and stable at 343 K and at a pH of 8.4. Comparison of the structure of BSX with those of other thermostable GH10 xylanases optimally active at acidic or close to neutral pH showed that the solvent-exposed acidic amino acids, Asp and Glu, are markedly enhanced in BSX, while solvent-exposed Asn was noticeably depleted. The BSX crystal structure when compared with putative three-dimensional homology models of other extracellular alkalophilic GH10 xylanases from alkalophilic organisms suggests that a protein surface rich in acidic residues may be an important feature common to these alkali thermostable enzymes. A comparison of the surface features of BSX and of halophilic proteins allowed us to predict the activity of BSX at high salt concentrations, which we verified through experiments. This offered us important lessons in the polyextremophilicity of proteins, where understanding the structural features of a protein stable in one set of extreme conditions provided clues about the activity of the protein in other extreme conditions. The work brings to the fore the role of the nature and composition of solvent-exposed residues in the adaptation of enzymes to polyextreme conditions, as in BSX.
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Manikandan K, Jagtap S, Rao M, Ramakumar S. Crystallization and preliminary X-ray characterization of a thermostable low-molecular-weight 1,4-beta-D-glucan glucohydrolase from an alkalothermophilic Thermomonospora sp. Acta Crystallogr Sect F Struct Biol Cryst Commun 2006; 62:385-7. [PMID: 16582491 PMCID: PMC2222567 DOI: 10.1107/s1744309106007949] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Accepted: 03/04/2006] [Indexed: 11/10/2022]
Abstract
Cellulases catalyze the hydrolysis of beta-1,4-glycosidic linkages within cellulose, the most abundant organic polymer on earth. The cellulase (TSC; EC 3.2.1.4) from an alkalothermophilic Thermomonospora sp. has a low molecular weight of 14.2 kDa. It is optimally active at 323 K and stable over the wide pH range of 5-9. Moreover, it has bifunctional activity against cellulose and xylan polymers. In this study, TSC was purified from the native source and crystallized by the hanging-drop vapour-diffusion method. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 49.9, b = 79.5, c = 99.7 angstroms, and diffract to better than 2.3 angstroms resolution.
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Affiliation(s)
- K. Manikandan
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
| | - S. Jagtap
- Division of Biochemical Sciences, National Chemical Laboratory, Pune 411 008, India
| | - M. Rao
- Division of Biochemical Sciences, National Chemical Laboratory, Pune 411 008, India
| | - S. Ramakumar
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
- Bioinformatics Centre, Indian Institute of Science, Bangalore 560 012, India
- Correspondence e-mail:
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Manikandan K, Bhardwaj A, Ghosh A, Reddy VS, Ramakumar S. Crystallization and preliminary X-ray study of a family 10 alkali-thermostable xylanase from alkalophilic Bacillus sp. strain NG-27. Acta Crystallogr Sect F Struct Biol Cryst Commun 2005; 61:747-9. [PMID: 16511146 PMCID: PMC1952343 DOI: 10.1107/s1744309105020518] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [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: 04/22/2005] [Accepted: 06/28/2005] [Indexed: 11/10/2022]
Abstract
Xylanases (EC 3.2.1.8) catalyze the hydrolysis of beta-1,4-glycosidic linkages within xylan, a major hemicellulose component in the biosphere. The extracellular endoxylanase (XylnA) from the alkalophilic Bacillus sp. strain NG-27 belongs to family 10 of the glycoside hydrolases. It is active at 343 K and pH 8.4. Moreover, it has attractive features from the point of view of utilization in the paper pulp, animal feed and baking industries since it is an alkali-thermostable protein. In this study, XylnA was purified from the native host source and crystallized by the hanging-drop vapour-diffusion method. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 174.5, b = 54.7, c = 131.5 A, beta = 131.2 degrees, and diffract to better than 2.2 A resolution.
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Affiliation(s)
- K. Manikandan
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
| | - Amit Bhardwaj
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India
| | - Amit Ghosh
- Institute of Microbial Technology, Sector 39-A, Chandigarh 160 036, India
| | - V. S. Reddy
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110 067, India
| | - S. Ramakumar
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
- Bioinformatics Centre, Indian Institute of Science, Bangalore 560 012, India
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Abstract
A comprehensive database analysis of C--H...O hydrogen bonds in 3124 alpha-helices and their corresponding helix termini has been carried out from a nonredundant data set of high-resolution globular protein structures resolved at better than 2.0 A in order to investigate their role in the helix, the important protein secondary structural element. The possible occurrence of 5 --> 1 C--H...O hydrogen bond between the ith residue CH group and (i - 4)th residue C==O with C...O < or = 3.8 A is studied, considering as potential donors the main-chain Calpha and the side-chain carbon atoms Cbeta, Cgamma, Cdelta and Cepsilon. Similar analysis has been carried out for 4 --> 1 C--H...O hydrogen bonds, since the C--H...O hydrogen bonds found in helices are predominantly of type 5 --> 1 or 4 --> 1. A total of 17,367 (9310 of type 5 --> 1 and 8057 of type 4 --> 1) C--H...O hydrogen bonds are found to satisfy the selected criteria. The average stereochemical parameters for the data set suggest that the observed C--H...O hydrogen bonds are attractive interactions. Our analysis reveals that the Cgamma and Cbeta hydrogen atom(s) are frequently involved in such hydrogen bonds. A marked preference is noticed for aliphatic beta-branched residue Ile to participate in 5 --> 1 C--H...O hydrogen bonds involving methylene Cgamma 1 atom as donor in alpha-helices. This may be an enthalpic compensation for the greater loss of side-chain conformational entropy for beta-branched amino acids due to the constraint on side-chain torsion angle, namely, chi1, when they occur in helices. The preference of amino acids for 4 --> 1 C--H...O hydrogen bonds is found to be more for Asp, Cys, and for aromatic residues Trp, Phe, and His. Interestingly, overall propensity for C--H...O hydrogen bonds shows that a majority of the helix favoring residues such as Met, Glu, Arg, Lys, Leu, and Gln, which also have large side-chains, prefer to be involved in such types of weak attractive interactions in helices. The amino acid side-chains that participate in C--H...O interactions are found to shield the acceptor carbonyl oxygen atom from the solvent. In addition, C--H...O hydrogen bonds are present along with helix stabilizing salt bridges. A novel helix terminating interaction motif, X-Gly with Gly at C(cap) position having 5 --> 1 Calpha--H...O, and a chain reversal structural motif having 1 --> 5 Calpha-H...O have been identified and discussed. Our analysis highlights that a multitude of local C--H...O hydrogen bonds formed by a variety of amino acid side-chains and Calpha hydrogen atoms occur in helices and more so at the helix termini. It may be surmised that the main-chain Calpha and the side-chain CH that participate in C--H...O hydrogen bonds collectively augment the cohesive energy and thereby contribute together with the classical N--H...O hydrogen bonds and other interactions to the overall stability of helix and therefore of proteins.
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Affiliation(s)
- K Manikandan
- Department of Physics, Indian Institute of Science, Bangalore, India
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Manikandan K, Misra KP, Ramachandran V. A case of massive arterio venous malformation of the scalp. Indian J Thorac Cardiovasc Surg 2003. [DOI: 10.1007/s12055-003-0005-4] [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] Open
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46
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Natesh R, Manikandan K, Bhanumoorthy P, Viswamitra MA, Ramakumar S. Thermostable xylanase from Thermoascus aurantiacus at ultrahigh resolution (0.89 A) at 100 K and atomic resolution (1.11 A) at 293 K refined anisotropically to small-molecule accuracy. Acta Crystallogr D Biol Crystallogr 2003; 59:105-17. [PMID: 12499546 DOI: 10.1107/s0907444902020164] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2002] [Accepted: 11/05/2002] [Indexed: 11/10/2022]
Abstract
Thermoascus aurantiacus xylanase is a thermostable enzyme which hydrolyses xylan, a major hemicellulose component of the biosphere. The crystal structure of this F/10 family xylanase, which has a triosephosphate isomerase (TIM) barrel (beta/alpha)(8) fold, has been solved to small-molecule accuracy at atomic resolution (1.11 A) at 293 K (RTUX) and at ultrahigh resolution (0.89 A) at 100 K (CTUX) using X-ray diffraction data sets collected on a synchrotron light source, resulting in R/R(free) values of 9.94/12.36 and 9.00/10.61% (for all data), respectively. Both structures were refined with anisotropic atomic displacement parameters. The 0.89 A structure, with 177 476 observed unique reflections, was refined without any stereochemical restraints during the final stages. The salt bridge between Arg124 and Glu232, which is bidentate in RTUX, is water-mediated in CTUX, suggesting the possibility of plasticity of ion pairs in proteins, with water molecules mediating some of the alternate arrangements. Two buried waters present inside the barrel form hydrogen-bond interactions with residues in strands beta2, beta3, beta4 and beta7 and presumably contribute to structural stability. The availability of accurate structural information at two different temperatures enabled the study of the temperature-dependent deformations of the TIM-barrel fold of the xylanase. Analysis of the deviation of corresponding C(alpha) atoms between RTUX and CTUX suggests that the interior beta-strands are less susceptible to changes as a function of temperature than are the alpha-helices, which are on the outside of the barrel. betaalpha-loops, which are longer and contribute residues to the active-site region, are more flexible than alphabeta-loops. The 0.89 A structure represents one of the highest resolution structures of a protein of such size with one monomer molecule in the asymmetric unit and also represents the highest resolution TIM-barrel fold structure to date. It may provide a useful template for theoretical modelling studies of the structure and dynamics of the ubiquitous TIM-barrel fold.
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Affiliation(s)
- R Natesh
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
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Ramakumar S, Natesh R, Manikandan K, Bhanumoothy P, Viswamitra MA. Xylanase at ultra high 0.89 Å (100 K) and atomic 1.11 Å (293 K) resolutions: evidence for salt bridge plasticity. Acta Crystallogr A 2002. [DOI: 10.1107/s0108767302085902] [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: 11/10/2022] Open
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