1
|
Petrich C, Dimroth A, Kraus KM, Winter J, Matejcek C, Butzek M, Natour G, Ravichandran M, Zimmermann M, Aulenbacher K, Galek M, Wilkens J, Combs SE, Bartzsch S. Towards Clinical Translation of Microbeam Radiation Therapy (MRT) with a Compact Source. Int J Radiat Oncol Biol Phys 2023; 117:S38-S39. [PMID: 37784488 DOI: 10.1016/j.ijrobp.2023.06.308] [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) MRT is an innovative concept of spatially fractionated radiation therapy that has demonstrated substantially improved normal tissue tolerance while achieving local tumor control in a wealth of preclinical studies. In MRT a collimator shapes a few micrometers wide planar x-ray beams with a spacing of a few 100 µm. MRT has the potential to improve cancer treatment substantially. However, until now, only a few large 3rd generation synchrotrons provide beam parameters that would allow patient treatments and therefore, MRT has not yet become clinically available. For a clinical translation, compact x-ray sources are required, that produce high dose rate orthovoltage x-rays from a micrometer sized emitter. MATERIALS/METHODS We developed and built a first prototype of a line focus x-ray tube (LFxT) dedicated to preclinical MRT research. By exploiting the heat capacity limit, the LFxT can deliver dose rates above 100 Gy/s from a just 50 µm-wide focal spot without destroying the rapidly (>200 Hz) rotating x-ray target. A bespoke collimator splits the homogeneous x-ray field into 50 µm wide high-dose peaks separated by 350 µm wide low-dose troughs (valleys). While the prototype in our lab is restricted to a power of 90 kW and 10 Gy/s at 300 kVp, we have started the development of the first clinically usable LFxT-2 at 1.5 MW power and >100 Gy/s at 600 kVp beam quality. We investigated the clinical applicability of the LFxT-2 by performing retrospective treatment planning studies. In particular, we were examining, whether 600 kVp photons would suffice to meet clinical dose constraints in MRT treatments treatment scenarios for first clinical use of MRT. We coupled the open source platform 3D Slicer with an in-house developed dose calculation algorithm for MRT treatment planning. For comparability of spatially fractionated MRT doses with conventional broad beam treatments, the MRT dose was converted to equivalent uniform dose (EUD) and equivalent doses in 2-Gy-fractions (EQD2). The 3D Slicer RT toolkit enabled the dosimetric analysis based on dose volume histograms (DVHs). RESULTS We installed a preclinical prototype of the LFxT that is currently put into operation and commissioned. Simulations show the feasibility of the next generation LFxT-2 with more than 100 Gy/s peak dose rate. Planned MRT dose distributions with the LFxT-2 meet established radiotherapy dose constraints in many of the investigated clinical cases. However, treatment planning procedures are not yet optimal and require improvement. CONCLUSION In a next step, we will build the LFxT-2 and aim for first clinical MRT trials at this source. In order to further improve calculated MRT dose distributions, we will implement inverse treatment planning techniques.
Collapse
Affiliation(s)
- C Petrich
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Munich, Germany; Neutron Source Heinz Maier-Leibnitz (FRM II), Munich, Germany
| | - A Dimroth
- Research Centre Juelich, Juelich, Germany
| | - K M Kraus
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Munich, Germany; Institute of Radiation Medicine (IRM), Helmholtz Zentrum München (HMGU) GmbH German Research Center for Environmental Health, Neuherberg, Germany
| | - J Winter
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Munich, Germany; Institute for Radiation Medicine, Helmholtz Zentrum München, Neuherberg, Germany
| | - C Matejcek
- Helmholtz Institute Mainz, Mainz, Germany
| | - M Butzek
- Research Centre Juelich, Juelich, Germany
| | - G Natour
- Research Centre Juelich, Juelich, Germany
| | - M Ravichandran
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Munich, Germany; Technical University of Munich, Munich, Germany
| | | | | | - M Galek
- University of Applied Sciences Munich, Munich, Germany
| | - J Wilkens
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Munich, Germany
| | - S E Combs
- Institute for Radiation Medicine, Helmholtz Zentrum München, Neuherberg, Germany; Department of Radiation Oncology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - S Bartzsch
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Munich, Germany; Neutron Source Heinz Maier-Leibnitz (FRM II), Munich, Germany
| |
Collapse
|
2
|
Thandlam V, Rahaman H, Rutgersson A, Sahlee E, Ravichandran M, Ramakrishna SSVS. Quantifying the role of antecedent Southwestern Indian Ocean capacitance on the summer monsoon rainfall variability over homogeneous regions of India. Sci Rep 2023; 13:5553. [PMID: 37020132 PMCID: PMC10076287 DOI: 10.1038/s41598-023-32840-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 04/03/2023] [Indexed: 04/07/2023] Open
Abstract
The role of ocean variability is at a focal point in improving the weather and climate forecasts at different spatial and temporal scales. We study the effect of antecedent southwestern Indian Ocean mean sea level anomaly (MSLA) and sea surface temperature anomalies (SSTA) as a proxy to upper ocean heat capacitance on all India summer monsoon rainfall (AISMR) during 1993-2019. SSTA and MSLA over the southwestern Indian Ocean (SWIO) have been influenced by El Niño-Southern Oscillation (ENSO), the impact of ENSO-induced SWIO variability was low on rainfall variability over several homogeneous regions. Rainfall over northeast (NE) and North India (EI) has been modulated by ENSO-induced SSTA and MSLA over SWIO, thus effecting the total AISMR magnitude. The ENSO-induced changes in heat capacitance (SSTA and MSLA) over SWIO during antecedent months has less impact on west coast of India, central India and North India (NI) rainfall variability. The long-term trend in pre-monsoonal SSTA and MSLA over SWIO shows decreasing rainfall trend over NI, NE, and EI in the recent time. Furthermore, the cooler (warmer) anomaly over the western Indian Ocean affects rainfall variability adversely (favourably) due to the reversal of the wind pattern during the pre-monsoon period. While SSTA and MSLA are increasing in the SWIO, large-scale variability of these parameters during preceding winter and pre-monsoon months combined with surface winds could impact the inter-annual AISMR variability over homogeneous regions of India. Similarly, from an oceanic perspective, the antecedent heat capacitance over SWIO on an inter-annual time scale has been the key to the extreme monsoon rainfall variability.
Collapse
Affiliation(s)
- Venugopal Thandlam
- Air, Water and Landscape Science (LUVAL), Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
- The Center for Environment and Development Studies Research Forum, Uppsala University, Uppsala, Sweden.
- Centre of Natural Hazards and Disaster Science, Uppsala University, Uppsala, Sweden.
- Department of Meteorology and Oceanography, Andhra University, Visakhapatnam, India.
| | - Hasibur Rahaman
- ESSO-Indian National Centre for Ocean Information Services (INCOIS), Ministry of Earth Sciences, Hyderabad, India
| | - Anna Rutgersson
- Air, Water and Landscape Science (LUVAL), Department of Earth Sciences, Uppsala University, Uppsala, Sweden
- Centre of Natural Hazards and Disaster Science, Uppsala University, Uppsala, Sweden
| | - Erik Sahlee
- Air, Water and Landscape Science (LUVAL), Department of Earth Sciences, Uppsala University, Uppsala, Sweden
| | - M Ravichandran
- Earth System Science Organization, Ministry of Earth Sciences, New Delhi, India
| | - S S V S Ramakrishna
- Department of Meteorology and Oceanography, Andhra University, Visakhapatnam, India
| |
Collapse
|
3
|
Shantharaman P, Anandakrishnan V, Sathish S, Ravichandran M, Naveenkumar R, Jayasathyakawin S, Rajesh S. Investigations on the microstructure and properties of yttria and silicon carbide reinforced aluminium composites. Heliyon 2023; 9:e15462. [PMID: 37128332 PMCID: PMC10147978 DOI: 10.1016/j.heliyon.2023.e15462] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 03/30/2023] [Accepted: 04/10/2023] [Indexed: 05/03/2023] Open
Abstract
Powder Metallurgy (PM) was used to synthesize SiC (0, 5, 10, 15 & 20 wt%) and 1 wt% Yttria (Y2O3) reinforced aluminium (Al) metal matrix composites. The Al-SiC-Y2O3 hybrid composites samples were prepared for density (ρ), hardness (VHN), mechanical, tribological, and microstructural studies in accordance with ASTM standards. SEM images revealed an even spreading of SiC particles throughout the Al matrix and composition was verified by the characterization techniques. The addition of SiC and Y2O3 to their respective composites improved the VHN and 'ρ'. The compressive strength (CS) of Al-SiC-Y2O3 composites increased while increasing the SiC. The higher compression strength (405 MPa) was obtained for the Al - 1 wt% Y2O3-20 wt% SiC- hybrid composites. The thermal conductivity (K) of Al-SiC-Y2O3 samples diminishes, as the hard SiC particles are gradually added. Furthermore, it was observed that accumulative the wt% of SiC in the aluminium metal matrix (AMMC) results in a novel material with a decreased wear rate. The better properties was achieved for the samples contain 20 wt% of SiC content in Al - 1 wt% Y2O3 matrix.
Collapse
Affiliation(s)
- P.P. Shantharaman
- Department of Mechanical Engineering, Kings College of Engineering, Punalkulam, 613303, Tamil Nadu, India
| | - V. Anandakrishnan
- Department of Production Engineering, National Institute of Technology, Tiruchirappalli, 620 015, Tamil Nadu, India
| | - S. Sathish
- Department of Mechatronics Engineering, K.S. Rangasamy College of Technology, Tiruchengode, Namakkal, 637215, Tamil Nadu, India
| | - M. Ravichandran
- Department of Mechanical Engineering, K Ramakrishnan College of Engineering, Samayapuram, 621112, Trichy, Tamil Nadu, India
- Corresponding author.
| | - R. Naveenkumar
- Department of Mechanical Engineering, K Ramakrishnan College of Engineering, Samayapuram, 621112, Trichy, Tamil Nadu, India
| | - S. Jayasathyakawin
- Department of Mechanical Engineering, K Ramakrishnan College of Engineering, Samayapuram, 621112, Trichy, Tamil Nadu, India
| | - S. Rajesh
- Department of Mechanical Engineering, Kalasalingam Academy of Research and Education, Krishnankoil, 626126, Virudhunagar, Tamil Nadu, India
| |
Collapse
|
4
|
Sathish T, Mohanavel V, Raja T, Ravichandran M, Murugan P, Suresh Kumar S, Alqahtani S, Alshehery S, Lalvani JIJR. Hybrid MWCNT and TiO 2 Nanoparticle-Suspended Waste Tyre Oil Biodiesel for CI Engines. Bioinorg Chem Appl 2023; 2023:8626155. [PMID: 36779008 PMCID: PMC9918359 DOI: 10.1155/2023/8626155] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 10/12/2022] [Accepted: 11/25/2022] [Indexed: 02/05/2023] Open
Abstract
Nowadays, scarcity arises in almost all our basic needs, including water, fuel, and food. Recycling used and scrapped things for a valuable commodity is highly appreciable for compensating for the globally fast-growing demand. This paper aims to investigate waste tyre oil for preparing biodiesel for CI engines by enhancing their performance with hybrid nanoparticles for preparing nanofuel and hybrid nanofuel. The nanoparticles (30-40 nm) of MWCNT and TiO2 were utilized to prepare nanofuels with nanoparticle concentrations of MWCNT (300 ppm) and TiO2 (300 ppm), respectively. In the case of hybrid nanofuel, the nanoparticle concentration of MWCNT (150 ppm) and TiO2 (150 ppm) was preferred. The performance of the proposed nanofuel and hybrid nanofuel with pure diesel was evaluated. The proposed fuel performance outperforms the combustion performance, has higher engine efficiency, and has fewer emissions. The best performances were noticed in hybrid nanofuel that has 32% higher brake thermal efficiency than diesel and 24% and 4% lower BSFC and peak pressure than diesel, respectively. The emission performance is also 29%, 50%, and 13% lower in CO, HC, and CO2 emissions than that in pure diesel.
Collapse
Affiliation(s)
- T. Sathish
- Department of Mechanical Engineering, Saveetha School of Engineering, SIMATS, Chennai 602105, Tamil Nadu, India
| | - V. Mohanavel
- Centre for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Chennai 600073, Tamil Nadu, India
- Department of Mechanical Engineering, School of Technology, Glocal University, Delhi-Yamunotri Marg, Uttar Pradesh, 247121, India
| | - T. Raja
- Material Science Lab, Department of Prosthodontics, Saveetha Dental College and Hospitals, SIMATS University, Chennai 600077, Tamil Nadu, India
| | - M. Ravichandran
- Department of Mechanical Engineering, K. Ramakrishnan College of Engineering, Trichy 621112, Tamil Nadu, India
- Department of Mechanical Engineering and University Centre for Research & Development, Chandigarh University, Mohali 140413, Punjab, India
| | - P. Murugan
- Centre for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Chennai 600073, Tamil Nadu, India
| | - S. Suresh Kumar
- Centre for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Chennai 600073, Tamil Nadu, India
| | - Sultan Alqahtani
- College of Engineering Mechanical Engineering Department, King Khalid University, Abha, Saudi Arabia
| | - Sultan Alshehery
- College of Engineering Mechanical Engineering Department, King Khalid University, Abha, Saudi Arabia
| | - J. Isaac Joshua Ramesh Lalvani
- Department of Mechanical Engineering, Faculty of Mechanical and Production Engineering, AMIT, Arbaminch University, Ethiopia
| |
Collapse
|
5
|
Jayasathyakawin S, Ravichandran M. Fabrication and wear behaviour of Mg-3wt.%Al- x wt. % SiC composites. Heliyon 2023; 9:e13679. [PMID: 36852037 PMCID: PMC9957713 DOI: 10.1016/j.heliyon.2023.e13679] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 02/08/2023] [Accepted: 02/08/2023] [Indexed: 02/22/2023] Open
Abstract
In this work, Silicon Carbide (SiC) reinforced Mg/3Al matrix composite was developed via powder metallurgy (PM) method. Friction coefficient (COF) and wear rate (WR) of the composite was studied using Pin on disc wear tester. Scanning Electron Microscope (SEM) was used to investigate the microstructure of sintered samples. During the experiments, L16 orthogonal design was followed. Wear analysis was done with four wear control factors such as the reinforcement (Wt.%), the applied load ('P'), the sliding velocity ('V') and the sliding distance ('D'). In this study, the optimal combination of parameters was found using signal-to-noise (S/N) ratio analysis. Based on the analysis of variance (ANOVA), the 'P' and Wt.% of SiC are the two parameters that have the greatest influence on WR and COF. From the analysis, Mg/3Al/9SiCcomposites exhibited better wear properties among other composition tested. Worn surface analysis was conducted for the tested samples and the SEM images are reported.
Collapse
Affiliation(s)
- S Jayasathyakawin
- Department of Mechanical Engineering, K. Ramakrishnan College of Engineering, Samayapuram, Trichy, 621112, India
| | - M Ravichandran
- Department of Mechanical Engineering, K. Ramakrishnan College of Engineering, Samayapuram, Trichy, 621112, India
| |
Collapse
|
6
|
Shyamlal C, Shanmugavel R, Jappes JTW, Nair A, Ravichandran M, Abuthakeer SS, Prakash C, Dixit S, Vatin NI. Corrosion Behavior of Friction Stir Welded AA8090-T87 Aluminum Alloy. Materials (Basel) 2022; 15:ma15155165. [PMID: 35897597 PMCID: PMC9332354 DOI: 10.3390/ma15155165] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 07/20/2022] [Accepted: 07/20/2022] [Indexed: 11/25/2022]
Abstract
Aerospace alloys with reduced wall thickness but possessing higher hardness, good tensile strength and reasonable corrosion resistance are essential in manufacturing of structures such as fuselage. In this work, friction stir welding has been carried out on such an aerospace aluminum alloy AA8090 T87 which contains 2.3% lithium. Tool rotational speed of 900 rpm and traverse speeds of 90 mm/min., 110 mm/min. are the welding parameters. Hardness analysis, surface roughness analysis and corrosion analysis are conducted to analyze the suitability of the joint for the intended application. The samples were corrosion tested in acid alkali solution and they resulted in the formation of pits of varying levels which indicate the extent of surface degradation. Hardness of the samples was measured after corrosion analysis to observe the changes. The analysis suggests that the change in tool traverse speed transformed the corrosion behavior of the joint and affected both the hardness and surface roughness which mitigated the quality of the joint.
Collapse
Affiliation(s)
- Chandrasekaran Shyamlal
- Department of Mechanical Engineering, Kalasalingam Academy of Research and Education, Krishnankoil 626126, India; (C.S.); (R.S.); (J.T.W.J.); (A.N.)
| | - Rajesh Shanmugavel
- Department of Mechanical Engineering, Kalasalingam Academy of Research and Education, Krishnankoil 626126, India; (C.S.); (R.S.); (J.T.W.J.); (A.N.)
| | - J. T. Winowlin Jappes
- Department of Mechanical Engineering, Kalasalingam Academy of Research and Education, Krishnankoil 626126, India; (C.S.); (R.S.); (J.T.W.J.); (A.N.)
| | - Anish Nair
- Department of Mechanical Engineering, Kalasalingam Academy of Research and Education, Krishnankoil 626126, India; (C.S.); (R.S.); (J.T.W.J.); (A.N.)
| | - M. Ravichandran
- Department of Mechanical Engineering, K Ramakrishnan College of Engineering, Tiruchirappalli 621112, India;
| | - S. Syath Abuthakeer
- Department of Mechanical Engineering, PSG College of Technology, Coimbatore 641004, India;
| | - Chander Prakash
- School of Mechanical Engineering, Lovely Professional University, Phagwara 144411, India
- Division of Research and Development, Lovely Professional University, Phagwara 144411, India
- Correspondence: (C.P.); (S.D.)
| | - Saurav Dixit
- Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia;
- Division of Research & Innovation, Uttaranchal University, Dehradun 248007, India
- Correspondence: (C.P.); (S.D.)
| | - N. I. Vatin
- Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia;
| |
Collapse
|
7
|
Gopikrishnan C, Ravichandran M. Investigations on Mechanical and Wear Properties of Molybdenum Trioxide-Reinforced Aluminum Alloy (AA7075) Matrix Composites Produced via Stir Casting Process. Arab J Sci Eng 2022. [DOI: 10.1007/s13369-022-07059-y] [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: 11/28/2022]
|
8
|
Mohanavel V, Ravichandran M, Ashraff Ali KS, Sathish T, Karthick A, Arungalai Vendan S, Velmurugan P, Salmen SH, Alfarraj S, Sivakumar S, Gebrekidan AM. Synthesis and Workability Behavior of Cu-X wt.% TiC ( x = 0, 4, 8, and 12) Powder Metallurgy Composites. Bioinorg Chem Appl 2022; 2022:8101680. [PMID: 35637640 PMCID: PMC9148246 DOI: 10.1155/2022/8101680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 10/22/2021] [Accepted: 04/20/2022] [Indexed: 11/24/2022] Open
Abstract
In this work, copper (Cu) matrix composite reinforced with titanium carbide (TiC) was fabricated by powder metallurgy (PM) method with the varying TiC content from 0% to 12% by weight in the step of 4%. The required weight percentage of powders was milled in an indigenously developed ball milling setup. Green compacts were made using a computer-controlled hydraulic press (400 kN) and sintered in a muffle furnace at a temperature of 950°C. Scanning electron microscope (SEM) was used to analyze the distribution of TiC particles in Cu matrix in as-sintered conditions. X-ray diffraction (XRD) analysis resulted in the existence of respective phases in the produced composites. The structural characteristics such as stress, strain, dislocation density, and grain size of the milled composites were evaluated. Cold upsetting was conducted for the sintered composites at room temperature to evaluate the axial (σ z ), hoop (σ ө ), hydrostatic (σ m ), and effective (σ eff ) true stresses. These stresses were analyzed against true axial strain (ε z ). Results showed that the increase in the inclusion of weight percentage of TiC into the Cu matrix increases density, hardness, (σ z ), (σ ө ), (σ m ), (σ eff ), and stress ratio parameters such as (σ z /σ eff ), (σ θ /σ eff ), (σ m /σ eff ), and (σ z /σ θ ) of the composites.
Collapse
Affiliation(s)
- V. Mohanavel
- Centre for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Chennai, 600073 Tamil Nadu, India
- Department of Mechanical Engineering, Chandigarh University, Mohali 140413, Punjab, India
| | - M. Ravichandran
- Department of Mechanical Engineering, K. Ramakrishnan College of Engineering, Trichy-621112, Tamil Nadu, India
- Department of Mechanical Engineering and University Centre for Research & Development, Chandigarh University, Mohali 140413, Punjab, India
| | - K. S. Ashraff Ali
- Department of Mechanical Engineering, C. Abdul Hakeem College of Engineering and Technology, Vellore 632509, Tamil Nadu, India
| | - T. Sathish
- Department of Mechanical Engineering, Saveetha School of Engineering, SIMATS, Chennai 602 105, Tamil Nadu, India
| | - Alagar Karthick
- Department of Electrical and Electronics Engineering, KPR Institute of Engineering and Technology, Coimbatore 641407, Tamil Nadu, India
| | - S. Arungalai Vendan
- Department of Electronics and Communication, Dayananda Sagar University, Bengaluru, Karnataka, India
| | - Palanivel Velmurugan
- Centre for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Chennai, 600073 Tamil Nadu, India
| | - Saleh H. Salmen
- Department of Botany and Microbiology, College of Science, King Saud University, PO. Box 2455, Riyadh 11451, Saudi Arabia
| | - Saleh Alfarraj
- Zoology Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - S. Sivakumar
- Department of Bioenvironmental Energy, College of Natural Resources and Life Science, Pusan National University, Miryang-si 50463, Republic of Korea
| | - Atkilt Mulu Gebrekidan
- Department of Mechanical Engineering, Faculty of Mechanical Engineering, Arba Minch Institute of Technology (AMIT), Arba Minch University, Arba Minch, Ethiopia
| |
Collapse
|
9
|
Jena B, Bajish CC, Turner J, Ravichandran M, Kshitija S, Anilkumar N, Singh AK, Pradhan PK, Ray Y, Saini S. Mechanisms associated with the rapid decline in sea ice cover around a stranded ship in the Lazarev Sea, Antarctica. Sci Total Environ 2022; 821:153379. [PMID: 35085627 DOI: 10.1016/j.scitotenv.2022.153379] [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] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/07/2022] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
In the satellite data era starting from 1979, the extent of Antarctic sea ice increased moderately for the first 37 years. However, the extent decreased to record low levels from 2016 to 2020, with the drop being greatest in the Weddell and Lazarev Seas of the Southern Ocean. An important question for the scientific fraternity and policymakers is to understand what ocean-atmospheric processes triggered such a rapid decline in sea ice. We employ in-situ, satellite, and atmospheric reanalysis data to examine the causative mechanism of anomalous sea ice variability in the Lazarev Sea at a time of ice growth in the annual cycle (March-April 2019), when a cargo ship was stuck in extensive ice cover and freed following the unusual decline in sea ice. High-resolution Sentinel-1 synthetic aperture radar captured a distinct view of the ship location and track within extensive ice cover of fast sea ice, dense pack ice, and icebergs in the Lazarev Sea on 27 March 2019. Subsequently, the sea ice cover declined and reached the fourth lowest extent in the entire satellite record during April 2019 which was 25.6% lower than the long-term mean value of 2.65 × 106 km2. We show that the anomalous sea ice variability was due to the occurrence of eastward-moving polar cyclones, including a quasi-stationary explosive development that impacted sea ice through extreme changes in ocean-atmospheric conditions. The cyclone-induced dynamic (poleward propagation of ocean waves and ice motion) and thermodynamic (heat and moisture plumes from midlatitudes, ocean mixed layer warming) processes coupled with high tides provided a conducive environment for an exceptional decline in sea ice over the region of ship movement.
Collapse
Affiliation(s)
- B Jena
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Government of India, Vasco-da-Gama, India.
| | - C C Bajish
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Government of India, Vasco-da-Gama, India
| | - J Turner
- British Antarctic Survey, Natural Environment Research Council, Cambridge, UK
| | - M Ravichandran
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Government of India, Vasco-da-Gama, India
| | - S Kshitija
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Government of India, Vasco-da-Gama, India
| | - N Anilkumar
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Government of India, Vasco-da-Gama, India
| | - A K Singh
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Government of India, Vasco-da-Gama, India
| | - P K Pradhan
- Department of Physics, Sri Venkateswara University, Tirupati, India
| | - Y Ray
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Government of India, Vasco-da-Gama, India
| | - S Saini
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Government of India, Vasco-da-Gama, India
| |
Collapse
|
10
|
Waldman G, Ravichandran M, Clark J, Doucette M, Gerlach A, Lewis G, Fishman J. Pharmacokinetic Impact of Posaconazole Discontinuation on Tacrolimus Levels in Heart Transplant Recipients. J Heart Lung Transplant 2022. [DOI: 10.1016/j.healun.2022.01.1031] [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] Open
|
11
|
Sathish T, Mohanavel V, Velmurugan P, Saravanan R, Raja T, Ravichandran M, Alonazi WB, Sureshkumar S, Gebrekidan AM. Investigating Influences of Synthesizing Eco-Friendly Waste-Coir-Fiber Nanofiller-Based Ramie and Abaca Natural Fiber Composite Parameters on Mechanical Properties. Bioinorg Chem Appl 2022; 2022:6557817. [PMID: 35154295 PMCID: PMC8837429 DOI: 10.1155/2022/6557817] [Citation(s) in RCA: 2] [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: 10/31/2021] [Accepted: 12/20/2021] [Indexed: 11/17/2022] Open
Abstract
Clean technology-based natural fiber composite fabrication is the prime aim of this piece of research. Natural fibers highly replace metal usage in industries and automobile, marine, medical applications, and so on. Vast amounts of natural fibers are freely available in all areas. In this research, work nanofiller material such as nano form waste coir fiber is collected from used car seat. The 10 wt.% of nanofiller material is added to the preparation of natural nanocomposites (ramie and abaca fiber). Hybrid composites are fabricated with the influence of different process parameters, namely, fiber weight percentage (20 wt.%, 30 wt.%, 40 wt.%, and 50 wt.%), NaOH action % (4%, 6%, 8%, and 10%), compression pressure (9 MPa, 12 MPa, 15 MPa, and 18 MPa), and temperature (100°C, 120°C, 140°C, and 160°C). Furthermore, the strength of this hybrid composite has analyzed by conducting flexural, impact, and shore hardness tests. These tests have provided the influence of selected parameters and their effects on the results of experimental work. In the flexural analysis, 6% of NaOH action has offered maximum flexural strength of the specimens. Correspondingly in the impact test, 30 wt.% of fiber is produced higher impact strength. Finally, applying 15 Mpa of compression pressure records the maximum shore hardness.
Collapse
Affiliation(s)
- T. Sathish
- Department of Mechanical Engineering, Saveetha School of Engineering, SIMATS, Chennai 602 105, Tamil Nadu, India
| | - Vinayagam Mohanavel
- Centre for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Selaiyur, Chennai 600073, Tamil Nadu, India
| | - Palanivel Velmurugan
- Centre for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Selaiyur, Chennai 600073, Tamil Nadu, India
| | - R. Saravanan
- Department of Mechanical Engineering, Saveetha School of Engineering, SIMATS, Chennai 602 105, Tamil Nadu, India
| | - T. Raja
- Department of Mechanical Engineering, Vel Tech Rangarajan Dr. Sakunthala R&D Institute of Science and Technology, Chennai 600062, India
| | - M. Ravichandran
- Department of Mechanical Engineering, K. Ramakrishnan College of Engineering, Trichy 621112, Tamil Nadu, India
| | - Wadi B. Alonazi
- Health Administration Department, College of Business Administration, King Saud University, PO Box 71115, Riyadh 11587, Saudi Arabia
| | - Shanmugam Sureshkumar
- Department of Animal Resources Science, Dankook University, 119,Dandae-ro, Cheonan,31116, Republic of Korea
| | - Atkilt Mulu Gebrekidan
- Department of Mechanical Engineering, Faculty of Mechanical Engineering, Arba Minch Institute of Technology (AMIT), Arba Minch University, Addis Ababa, Ethiopia
| |
Collapse
|
12
|
Mohanavel V, Kumar KR, Sathish T, Velmurugan P, Karthick A, Ravichandran M, Alfarraj S, Almoallim HS, Sureshkumar S, JoshuaRamesh Lalvani JI. Investigation on Inorganic Salts K2TiF6 and KBF4 to Develop Nanoparticles Based TiB2 Reinforcement Aluminium Composites. Bioinorg Chem Appl 2022; 2022:8559402. [PMID: 35140762 PMCID: PMC8818420 DOI: 10.1155/2022/8559402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 10/25/2021] [Accepted: 01/04/2022] [Indexed: 11/17/2022] Open
Abstract
In the current research, AA6082 aluminium alloy matrix composites (AAMCs) incorporated with various weight fractions of titanium diboride (0, 3, 6, and 9 wt%) were prepared via an in situ casting technique. The exothermic reaction between inorganic powders like dipotassium hexafluorotitanate (K2TiF6) and potassium tetrafluoroborate (KBF4) in molten Al metal contributes to the development of titanium diboride content. The manufactured AA6082-TiB2 AAMCs were evaluated using a scanning electron microscope (SEM) and X-ray diffraction (XRD). The mechanical properties and wear rate (WR) of the AAMCs were investigated. XRD guarantees the creation of TiB2 phases and proves the nonappearance of reaction products in the AMCs. SEM studies depict the even dispersion of TiB2 in the matrix alloy. The mechanical and tribological properties (MTP) of the AAMCs showed improvement by the dispersion of TiB2 particles. The WR decreases steadily with TiB2 and the least WR is seen at nine weight concentrations of TiB2/AA6082 AAMCs. Fabricated composites revealed 47.9% higher flexural strength and 14.2% superior compression strength than the base AA6082 alloy.
Collapse
Affiliation(s)
- Vinayagam Mohanavel
- Centre for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Selaiyur, Chennai 600073, Tamil Nadu, India
| | - K. Ravi Kumar
- Department of Mechanical Engineering, KPR Institute of Engineering and Technology, Coimbatore-641407, Tamilnadu, India
| | - T. Sathish
- Department of Mechanical Engineering, Saveetha School of Engineering, SIMATS, Chennai 602 105, Tamil Nadu, India
| | - Palanivel Velmurugan
- Centre for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Selaiyur, Chennai 600073, Tamil Nadu, India
| | - Alagar Karthick
- Department of Electrical and Electronics Engineering, KPR Institute of Engineering and Technology, Coimbatore 641407, Tamil Nadu, India
| | - M. Ravichandran
- Department of Mechanical Engineering, K. Ramakrishnan College of Engineering, Tiruchirappalli-621112, Tamilnadu, India
| | - Saleh Alfarraj
- Zoology Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Hesham S. Almoallim
- Department of Oral and Maxillofacial Surgery, College of Dentistry, King Saud University, PO Box-60169, Riyadh-11545, Saudi Arabia
| | - Shanmugam Sureshkumar
- Department of Animal Resources Science, Dankook University, 119,Dandae-ro, Cheonan,31116, Republic of Korea
| | - J. Isaac JoshuaRamesh Lalvani
- Department of Mechanical Engineering, Faculty of Mechanical and Production Engineering, AMIT, Arbaminch University, Ethiopia
| |
Collapse
|
13
|
Shesu RV, Bhaskar TVSU, Rao EPR, Ravichandran M, Rao BV. An improved method for quality control of in situ data from Argo floats using α convex hulls. MethodsX 2021; 8:101337. [PMID: 34430242 PMCID: PMC8374363 DOI: 10.1016/j.mex.2021.101337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/31/2021] [Indexed: 12/02/2022] Open
Abstract
An improved method for detecting abnormal oceanic in situ temperature and salinity (T/S) profiles is developed. This procedure extends previous method developed by Udaya Bhaskar et al. [2017]. This method utilizes World Ocean Atlas 2013 gridded climatology which is on 0.25° x 0.25° resolution to build α convex hulls. These α shapes are then used to categorize good and bad in situ T/S data profiles. This extended method classify the entire profiles instead of data for standard depths to avoid any errors introduced by interpolation to standard depths. Like in previous method, an 'n' sided polygon (convex hull) encompassing the T/S profile data is constructed using Jarvis March algorithm and Points In Polygon (PIP) principle is employed to judge the profile as good or bad. Extensive sensitivity experiments were done for arriving at the optimal α value such that false positives and true negatives are minimized. All types of issues associated with the in situ oceanographic data are identified and quality flag assigned. Examples of this improved method as applied to few Argo floats are presented.The T/S profiles corresponding to region of interest are used to build α convex hulls. This extended method can be effectively used for quality control of entire profile and clearly demarcate the profile as good/bad. This method has the advantage of treating bulk of oceanographic in situ profiles data in a single go which filters out erroneous profile data from the good.
Collapse
Affiliation(s)
- R Venkat Shesu
- Indian National Centre for Ocean Information Services (INCOIS), Ministry of Earth Sciences (MoES), Hyderabad, Telangana 500090, India
| | - T V S Udaya Bhaskar
- Indian National Centre for Ocean Information Services (INCOIS), Ministry of Earth Sciences (MoES), Hyderabad, Telangana 500090, India
| | - E Pattabhi Rama Rao
- Indian National Centre for Ocean Information Services (INCOIS), Ministry of Earth Sciences (MoES), Hyderabad, Telangana 500090, India
| | - M Ravichandran
- National Centre for Polar and Ocean Research (NCPOR), Ministry of Earth Sciences (MoES), Headland Sada, Vasco-da-Gama, Goa 403804, India
| | - B Venkateswara Rao
- Jawaharlal Nehru Technological University (JNTU), Kukatpally, Hyderabad, Telangana 500085, India
| |
Collapse
|
14
|
Kaviarasu C, Prakash D, Ravichandran M. Minimization of nanoparticle deposition rate in a square duct with a 90° bend using taguchi technique. Appl Nanosci 2021. [DOI: 10.1007/s13204-020-01658-7] [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]
|
15
|
Ramya JE, Goldlin TJA, Kalyanaraman S, Ravichandran M. A pharmacovigilance study of covishield in a tertiary care teaching hospital in Tamil Nadu. J Pharmacol Pharmacother 2021. [DOI: 10.4103/jpp.jpp_63_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
16
|
Palla AR, Ravichandran M, Wang YX, Alexandrova L, Yang AV, Kraft P, Holbrook CA, Schürch CM, Ho ATV, Blau HM. Inhibition of prostaglandin-degrading enzyme 15-PGDH rejuvenates aged muscle mass and strength. Science 2020; 371:science.abc8059. [PMID: 33303683 DOI: 10.1126/science.abc8059] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 11/24/2020] [Indexed: 12/11/2022]
Abstract
Treatments are lacking for sarcopenia, a debilitating age-related skeletal muscle wasting syndrome. We identifed increased amounts of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), the prostaglandin E2 (PGE2)-degrading enzyme, as a hallmark of aged tissues, including skeletal muscle. The consequent reduction in PGE2 signaling contributed to muscle atrophy in aged mice and results from 15-PGDH-expressing myofibers and interstitial cells, such as macrophages, within muscle. Overexpression of 15-PGDH in young muscles induced atrophy. Inhibition of 15-PGDH, by targeted genetic depletion or a small-molecule inhibitor, increased aged muscle mass, strength, and exercise performance. These benefits arise from a physiological increase in PGE2 concentrations, which augmented mitochondrial function and autophagy and decreased transforming growth factor-β signaling and activity of ubiquitin-proteasome pathways. Thus, PGE2 signaling ameliorates muscle atrophy and rejuvenates muscle function, and 15-PGDH may be a suitable therapeutic target for countering sarcopenia.
Collapse
Affiliation(s)
- A R Palla
- Blau Laboratory, Stanford School of Medicine, Stanford, CA 94305, USA.,Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| | - M Ravichandran
- Blau Laboratory, Stanford School of Medicine, Stanford, CA 94305, USA.,Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Y X Wang
- Blau Laboratory, Stanford School of Medicine, Stanford, CA 94305, USA.,Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| | - L Alexandrova
- Vincent Coates Foundation Mass Spectrometry Laboratory, Stanford University, Stanford, CA, USA
| | - A V Yang
- Blau Laboratory, Stanford School of Medicine, Stanford, CA 94305, USA.,Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| | - P Kraft
- Blau Laboratory, Stanford School of Medicine, Stanford, CA 94305, USA.,Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| | - C A Holbrook
- Blau Laboratory, Stanford School of Medicine, Stanford, CA 94305, USA.,Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| | - C M Schürch
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford, CA 94305, USA.,Nolan Laboratory, Stanford School of Medicine, Stanford, CA 94305, USA
| | - A T V Ho
- Blau Laboratory, Stanford School of Medicine, Stanford, CA 94305, USA.,Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| | - H M Blau
- Blau Laboratory, Stanford School of Medicine, Stanford, CA 94305, USA. .,Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford, CA 94305, USA
| |
Collapse
|
17
|
Stalin B, Nagaprasad N, Vignesh V, Ravichandran M, Rajini N, Ismail SO, Mohammad F. Evaluation of mechanical, thermal and water absorption behaviors of Polyalthia longifolia seed reinforced vinyl ester composites. Carbohydr Polym 2020; 248:116748. [PMID: 32919554 DOI: 10.1016/j.carbpol.2020.116748] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [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: 04/11/2020] [Revised: 07/05/2020] [Accepted: 07/09/2020] [Indexed: 12/14/2022]
Abstract
This study presented a novel utilization of biomass solid waste, named Polyalthia longifolia (Mast tree) seed as a reinforcement in a composite, using a compression molding technique. An attempt was made to reinforce vinyl ester matrix (VE) with Polyalthia longifolia seed filler (PLSF), ranging from 5 to 50 wt% loadings. Mechanical properties of the fabricated Polyalthia longifolia seed filler/vinyl ester (PLSF-VE) composite samples were tested and analyzed. The results showed that the PLSF-VE composite exhibited optimum mechanical properties at 25 % wt of filler loading; ultimate tensile strength and modulus were approximately 32.50 MPa and 1.23 GPa, respectively. The ultimate flexural, impact strengths and hardness were observed around 125 MPa, 31.09 kJ/m2 and 36.50, respectively. The heat deflection test and thermo-gravimetric analysis depicted that the PLSF-VE composites withstood up to 66 °C and 430 °C, respectively. Furthermore, the PLSF and its various composite samples were studied, using energy-dispersive X-ray (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM).
Collapse
Affiliation(s)
- B Stalin
- Department of Mechanical Engineering, Anna University, Regional Campus Madurai, Madurai, 625 019, Tamil Nadu, India.
| | - N Nagaprasad
- Department of Mechanical Engineering, ULTRA College of Engineering and Technology, Madurai, 625107, Tamil Nadu, India
| | - V Vignesh
- Department of Mechanical Engineering, Sethu Institute of Technology, Pulloor, Kariapatti, 626 115, Tamil Nadu, India
| | - M Ravichandran
- Department of Mechanical Engineering, K. Ramakrishnan College of Engineering, Samayapuram, Tiruchirappalli, 621 112, Tamil Nadu, India
| | - Nagarajan Rajini
- Department of Mechanical Engineering, Kalasalingam University, Krishnankoil, Virudhunagar, 626 126, Tamil Nadu, India.
| | - Sikiru Oluwarotimi Ismail
- Department of Engineering, Centre for Engineering Research, School of Engineering and Computer Science, University of Hertfordshire, Hatfield, AL10 9AB, England, UK
| | - Faruq Mohammad
- Surfactants Research Chair, Department of Chemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia 11451
| |
Collapse
|
18
|
P J V, Ravichandran M, Subeesh MP, Chatterjee S, M N. Author Correction: Global warming hiatus contributed weakening of the Mascarene High in the Southern Indian Ocean. Sci Rep 2020; 10:5670. [PMID: 32205849 PMCID: PMC7089952 DOI: 10.1038/s41598-020-62006-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Vidya P J
- ESSO- National Centre for Polar and Ocean Research (NCPOR), Headland Sada, Goa, 403 804, India.
| | - M Ravichandran
- ESSO- National Centre for Polar and Ocean Research (NCPOR), Headland Sada, Goa, 403 804, India
| | - M P Subeesh
- ESSO- National Centre for Polar and Ocean Research (NCPOR), Headland Sada, Goa, 403 804, India
| | - Sourav Chatterjee
- ESSO- National Centre for Polar and Ocean Research (NCPOR), Headland Sada, Goa, 403 804, India
| | - Nuncio M
- ESSO- National Centre for Polar and Ocean Research (NCPOR), Headland Sada, Goa, 403 804, India
| |
Collapse
|
19
|
P J V, Ravichandran M, Subeesh MP, Chatterjee S, M N. Global warming hiatus contributed weakening of the Mascarene High in the Southern Indian Ocean. Sci Rep 2020; 10:3255. [PMID: 32094382 PMCID: PMC7039868 DOI: 10.1038/s41598-020-59964-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [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: 07/15/2019] [Accepted: 01/14/2020] [Indexed: 11/10/2022] Open
Abstract
The Mascarene High (MH) is a semi-permanent subtropical high-pressure zone in the South Indian Ocean. Apart from its large influence on African and Australian weather patterns, it also helps in driving the inter-hemispheric circulation between the Indian Ocean in the south and subcontinental landmass in the north. Using observations and reanalysis products, this study for the first time investigates recent warming trend observed in the MH region during the Global Warming Hiatus (GWH) period (1998–2016). Significant positive trends are observed in sea surface temperature (SST), sea surface height (SSH) and oceanic heat content (OHC) during this period in the MH region. Mixed layer heat budget analysis reveals the dominant role of heat advection in the observed warming trend. During the GWH period, stronger zonal currents advect the warm waters from the Western Pacific (WP) towards the MH region via the Indonesian Throughflow (ITF). This warming in the MH reduces the sea level pressure therein and establishes a weak pressure gradient between the MH and the northern hemisphere landmass. This in-turn weakens the cross-equatorial winds in the western Indian Ocean.
Collapse
Affiliation(s)
- Vidya P J
- ESSO- National Centre for Polar and Ocean Research (NCPOR), Headland Sada, Goa, 403 804, India.
| | - M Ravichandran
- ESSO- National Centre for Polar and Ocean Research (NCPOR), Headland Sada, Goa, 403 804, India
| | - M P Subeesh
- ESSO- National Centre for Polar and Ocean Research (NCPOR), Headland Sada, Goa, 403 804, India
| | - Sourav Chatterjee
- ESSO- National Centre for Polar and Ocean Research (NCPOR), Headland Sada, Goa, 403 804, India
| | - Nuncio M
- ESSO- National Centre for Polar and Ocean Research (NCPOR), Headland Sada, Goa, 403 804, India
| |
Collapse
|
20
|
Jayasathyakawin S, Ravichandran M, Baskar N, Anand Chairman C, Balasundaram R. Mechanical properties and applications of Magnesium alloy – Review. ACTA ACUST UNITED AC 2020. [DOI: 10.1016/j.matpr.2020.01.255] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
21
|
Dhinakaran V, Manoj Kumar K, Bupathi Ram P, Ravichandran M, Vinayagamoorthy M. A review on recent advancements in fused deposition modeling. ACTA ACUST UNITED AC 2020. [DOI: 10.1016/j.matpr.2019.12.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
22
|
Duraisamy J, Ravichandran M. Statin Induced Rhabdomyolysis. J Assoc Physicians India 2020; 68:55. [PMID: 31979607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
|
23
|
Jena B, Kumar A, Ravichandran M, Kern S. Mechanism of sea-ice expansion in the Indian Ocean sector of Antarctica: Insights from satellite observation and model reanalysis. PLoS One 2018; 13:e0203222. [PMID: 30281612 PMCID: PMC6169864 DOI: 10.1371/journal.pone.0203222] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/16/2018] [Indexed: 11/18/2022] Open
Abstract
In the backdrop of global warming, Antarctic sea-ice variability showed an overall expansion with the regional heterogeneity of increasing and decreasing patterns. Analysis of satellite derived sea-ice extent, during 1979 to 2015, in the Indian Ocean sector of Antarctica (IOA) revealed expansion of 2.4±1.2% decade-1. We find strengthening of westerly wind during the austral summer (between 50°S to 62°S) facilitated northward advection of a cool and fresh layer. Also, the strong westerly wind cools the upper ocean due to net heat loss from the ocean surface. The combined effect of northward advection of cold fresh layer and net heat loss from the surface, favours sea-ice expansion in the subsequent seasons, in the IOA region, north of 62°S. However, sea-ice retreat was observed near the Kerguelen Plateau, due to upper ocean warming, and hence a non-annular pattern of sea-ice extent in the IOA was observed.
Collapse
Affiliation(s)
- Babula Jena
- ESSO - National Centre for Antarctic and Ocean Research, Ministry of Earth Science, Government of India, Vasco-da-Gama, India
| | - Avinash Kumar
- ESSO - National Centre for Antarctic and Ocean Research, Ministry of Earth Science, Government of India, Vasco-da-Gama, India
| | - M. Ravichandran
- ESSO - National Centre for Antarctic and Ocean Research, Ministry of Earth Science, Government of India, Vasco-da-Gama, India
| | - Stefan Kern
- Integrated Climate Data Center (ICDC), Center for Earth System Research and Sustainability, University of Hamburg, Hamburg, Germany
| |
Collapse
|
24
|
Mathew S, Natesan U, Latha G, Venkatesan R, Rao RR, Ravichandran M. Observed Warming of Sea Surface Temperature in Response to Tropical Cyclone Thane in the Bay of Bengal. CURR SCI INDIA 2018. [DOI: 10.18520/cs/v114/i07/1407-1413] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
25
|
Abstract
We review here the molecular mechanisms employed by DNMTs and TET enzymes that are responsible for shaping the DNA methylation pattern of a mammalian cell.
Collapse
Affiliation(s)
| | | | - T. P. Jurkowski
- Universität Stuttgart
- Abteilung Biochemie
- Institute für Biochemie und Technische Biochemie
- Stuttgart D-70569
- Germany
| |
Collapse
|
26
|
Arivukkarasan S, Dhanalakshmi V, Stalin B, Ravichandran M. Mechanical and tribological behaviour of tungsten carbide reinforced aluminum LM4 matrix composites. Particulate Science and Technology 2017. [DOI: 10.1080/02726351.2017.1331285] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- S. Arivukkarasan
- Department of Mechanical Engineering, SACS M.A.V. M.M. Engineering College, Madurai, Tamil Nadu, India
| | - V. Dhanalakshmi
- Department of Mechanical Engineering, Thiagarajar College of Engineering, Madurai, Tamil Nadu, India
| | - B. Stalin
- Department of Mechanical Engineering, Anna University, Regional Campus Madurai, Madurai, Tamil Nadu, India
| | - M. Ravichandran
- Department of Mechanical Engineering, Chendhuran College of Engineering & Technology, Pudukkottai, Tamil Nadu, India
| |
Collapse
|
27
|
Sivareddy S, Paul A, Sluka T, Ravichandran M, Kalnay E. The pre-Argo ocean reanalyses may be seriously affected by the spatial coverage of moored buoys. Sci Rep 2017; 7:46685. [PMID: 28429748 PMCID: PMC5399374 DOI: 10.1038/srep46685] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [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: 10/05/2016] [Accepted: 03/24/2017] [Indexed: 11/09/2022] Open
Abstract
Assimilation methods, meant to constrain divergence of model trajectory from reality using observations, do not exactly satisfy the physical laws governing the model state variables. This allows mismatches in the analysis in the vicinity of observation locations where the effect of assimilation is most prominent. These mismatches are usually mitigated either by the model dynamics in between the analysis cycles and/or by assimilation at the next analysis cycle. However, if the observations coverage is limited in space, as it was in the ocean before the Argo era, these mechanisms may be insufficient to dampen the mismatches, which we call shocks, and they may remain and grow. Here we show through controlled experiments, using real and simulated observations in two different ocean models and assimilation systems, that such shocks are generated in the ocean at the lateral boundaries of the moored buoy network. They thrive and propagate westward as Rossby waves along these boundaries. However, these shocks are essentially eliminated by the assimilation of near-homogenous global Argo distribution. These findings question the fidelity of ocean reanalysis products in the pre-Argo era. For example, a reanalysis that ignores Argo floats and assimilates only moored buoys, wrongly represents 2008 as a negative Indian Ocean Dipole year.
Collapse
Affiliation(s)
- S Sivareddy
- ESSO-Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Pragathi Nagar, Hyderabad, 500090, India
| | - Arya Paul
- ESSO-Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Pragathi Nagar, Hyderabad, 500090, India
| | - Travis Sluka
- Department of Atmospheric and Oceanic Sciences, University of Maryland, College Park, Maryland, USA
| | - M Ravichandran
- ESSO-Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Pragathi Nagar, Hyderabad, 500090, India.,ESSO-National Centre for Antarctic and Ocean Research, Ministry of Earth Sciences, Headland Sada, Vasco-da-Gama, Goa 403804, India
| | - Eugenia Kalnay
- Department of Atmospheric and Oceanic Sciences, University of Maryland, College Park, Maryland, USA
| |
Collapse
|
28
|
Nayak S, Mohan R, Ravichandran M. Recent Antarctic Research in India: The National Committee Report to SCAR (2017). Proceedings of the Indian National Science Academy 2017. [DOI: 10.16943/ptinsa/2017/48943] [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: 11/13/2022]
|
29
|
|
30
|
Ravichandran M, Oza G, Velumani S, Ramirez JT, Garcia-Sierra F, Andrade NB, Vera A, Leija L, Garza-Navarro MA. Plasmonic/Magnetic Multifunctional nanoplatform for Cancer Theranostics. Sci Rep 2016; 6:34874. [PMID: 27721391 PMCID: PMC5056510 DOI: 10.1038/srep34874] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 09/09/2016] [Indexed: 12/18/2022] Open
Abstract
A multifunctional magneto-plasmonic CoFe2O4@Au core-shell nanoparticle was developed by iterative-seeding based method. This nanocargo consists of a cobalt ferrite kernel as a core (Nk) and multiple layers of gold as a functionalizable active stratum, (named as Nk@A after fifth iteration). Nk@A helps in augmenting the physiological stability and enhancing surface plasmon resonance (SPR) property. The targeted delivery of Doxorubicin using Nk@A as a nanopayload is demonstrated in this report. The drug release profile followed first order rate kinetics optimally at pH 5.4, which is considered as an endosomal pH of cells. The cellular MR imaging showed that Nk@A is an efficient T2 contrast agent for both L6 (r2-118.08 mM-1s-1) and Hep2 (r2-217.24 mM-1s-1) cells. Microwave based magnetic hyperthermia studies exhibited an augmentation in the temperature due to the transformation of radiation energy into heat at 2.45 GHz. There was an enhancement in cancer cell cytotoxicity when hyperthermia combined with chemotherapy. Hence, this single nanoplatform can deliver 3-pronged theranostic applications viz., targeted drug-delivery, T2 MR imaging and hyperthermia.
Collapse
Affiliation(s)
- M. Ravichandran
- Program on Nanoscience and Nanotechnology, Av. 2508 National Polytechnic Institute, Gustavo A. Madero, San Pedro Zacatenco, 07360 Mexico City, Mexico
| | - Goldie Oza
- Department of Genetics and Molecular Biology, Av. 2508 National Polytechnic Institute, Gustavo A. Madero, San Pedro Zacatenco, 07360 Mexico City, Mexico
| | - S. Velumani
- Department of Electrical Engineering, Av. 2508 National Polytechnic Institute, Gustavo A. Madero, San Pedro Zacatenco, 07360 Mexico City, Mexico
| | - Jose Tapia Ramirez
- Department of Genetics and Molecular Biology, Av. 2508 National Polytechnic Institute, Gustavo A. Madero, San Pedro Zacatenco, 07360 Mexico City, Mexico
| | - Francisco Garcia-Sierra
- Department of Cell Biology, Av. 2508 National Polytechnic Institute, Gustavo A. Madero, San Pedro Zacatenco, 07360 Mexico City, Mexico
| | - Norma Barragan Andrade
- Department of Cell Biology, Av. 2508 National Polytechnic Institute, Gustavo A. Madero, San Pedro Zacatenco, 07360 Mexico City, Mexico
| | - A. Vera
- Department of Electrical Engineering - Bioelectronics Section, CINVESTAV-IPN, Av. 2508 National Polytechnic Institute, Gustavo A. Madero, San Pedro Zacatenco, 07360 Mexico City
| | - L. Leija
- Department of Electrical Engineering - Bioelectronics Section, CINVESTAV-IPN, Av. 2508 National Polytechnic Institute, Gustavo A. Madero, San Pedro Zacatenco, 07360 Mexico City
| | - Marco A. Garza-Navarro
- Department of Mechanical and Electrical Engineering, Universidad Autonoma de Nuevo Leon, San Nicolás de Los Garza, Nuevo León, 66451 Mexico City, Mexico
| |
Collapse
|
31
|
Thamban M, Ravichandran M. ESSO–National Centre for Antarctic and Ocean Research. Proceedings of the Indian National Science Academy 2016. [DOI: 10.16943/ptinsa/2016/48509] [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: 11/13/2022]
|
32
|
Oza G, Ravichandran M, Merupo VI, Shinde S, Mewada A, Ramirez JT, Velumani S, Sharon M, Sharon M. Camphor-mediated synthesis of carbon nanoparticles, graphitic shell encapsulated carbon nanocubes and carbon dots for bioimaging. Sci Rep 2016; 6:21286. [PMID: 26905737 PMCID: PMC4764906 DOI: 10.1038/srep21286] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [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: 07/03/2015] [Accepted: 12/14/2015] [Indexed: 11/25/2022] Open
Abstract
A green method for an efficient synthesis of water-soluble carbon nanoparticles (CNPs), graphitic shell encapsulated carbon nanocubes (CNCs), Carbon dots (CDs) using Camphor (Cinnamomum camphora) is demonstrated. Here, we describe a competent molecular fusion and fission route for step-wise synthesis of CDs. Camphor on acidification and carbonization forms CNPs, which on alkaline hydrolysis form CNCs that are encapsulated by thick graphitic layers and on further reduction by sodium borohydride yielded CDs. Though excitation wavelength dependent photoluminescence is observed in all the three carbon nanostructures, CDs possess enhanced photoluminescent properties due to more defective carbonaceous structures. The surface hydroxyl and carboxyl functional groups make them water soluble in nature. They possess excellent photostability, higher quantum yield, increased absorption, decreased cytotoxicity and hence can be utilized as a proficient bio imaging agent.
Collapse
Affiliation(s)
- Goldie Oza
- Department of Electrical Engineering, CINVESTAV-IPN, Mexico D.F
| | - M Ravichandran
- Program on Nanoscience and Nanotechnology, CINVESTAV-IPN, Mexico D.F
| | - Victor-Ishrayelu Merupo
- Department of Electrical Engineering, CINVESTAV-IPN, Mexico D.F.,Institute of Molecules &Materials of Le Mans (IMMM) UMR CNRS 6283, Universite du Maine, 72085 Le Mans, France
| | | | - Ashmi Mewada
- Walchand Centre for Research in Nanotechnology and Bionanotechnology (wcRnb), Walchand College of Arts and Science, Walchand-Hirachand Marg, Ashok Chowk, Solapur-413006 MS, India
| | | | - S Velumani
- Department of Electrical Engineering, CINVESTAV-IPN, Mexico D.F.,Program on Nanoscience and Nanotechnology, CINVESTAV-IPN, Mexico D.F
| | - Madhuri Sharon
- Walchand Centre for Research in Nanotechnology and Bionanotechnology (wcRnb), Walchand College of Arts and Science, Walchand-Hirachand Marg, Ashok Chowk, Solapur-413006 MS, India
| | - Maheshwar Sharon
- Walchand Centre for Research in Nanotechnology and Bionanotechnology (wcRnb), Walchand College of Arts and Science, Walchand-Hirachand Marg, Ashok Chowk, Solapur-413006 MS, India
| |
Collapse
|
33
|
Ravichandran M, Oza G, Velumani S, Ramirez JT, Garcia-Sierra F, Andrade NB, Garza-Navarro MA, Garcia-Gutierrez DI, Lara-Estrada R, Sacristán-Rock E, Yi J. Cobalt ferrite nanowhiskers as T2 MRI contrast agent. RSC Adv 2015. [DOI: 10.1039/c4ra11934g] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A novel, one-step synthesis of one-dimensional cobalt ferrite nanowhiskers (CfW) is reported.
Collapse
Affiliation(s)
| | - Goldie Oza
- Department of Electrical Engineering
- México
| | - S. Velumani
- Program on Nanoscience and Nanotechnology
- México
- Department of Electrical Engineering
- México
- School of Information and Communication Engineering
| | | | - Francisco Garcia-Sierra
- Department of Cell Biology
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional
- México
| | - Norma Barragán Andrade
- Department of Cell Biology
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional
- México
| | | | | | - Rafael Lara-Estrada
- Department of Electrical Engineering
- Centro Nacional de Investigación en Imagenología e Instrumentación Médica
- Universidad Autónoma Metropolitana – Iztapalapa
- México
| | - Emilio Sacristán-Rock
- Department of Electrical Engineering
- Centro Nacional de Investigación en Imagenología e Instrumentación Médica
- Universidad Autónoma Metropolitana – Iztapalapa
- México
| | - Junsin Yi
- School of Information and Communication Engineering
- Sungkyunkwan University
- Suwon
- Korea
| |
Collapse
|
34
|
Marini M, Sasongko TH, Watihayati MS, Atif AB, Hayati F, Zabidi-Hussin ZAMH, Ravichandran M, Nishio H, Zilfalil BA. Allele-specific PCR for a cost-effective & time-efficient diagnostic screening of spinal muscular atrophy. Indian J Med Res 2012; 135:31-5. [PMID: 22382180 PMCID: PMC3307181 DOI: 10.4103/0971-5916.93421] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Background & objectives: Genetic diagnosis of spinal muscular atrophy (SMA) is complicated by the presence of SMN2 gene as majority of SMA patients show absence or deletion of SMN1 gene. PCR may amplify both the genes non selectively in presence of high amount of DNA. We evaluated whether allele-specific PCR for diagnostic screening of SMA is reliable in the presence of high amount of genomic DNA, which is commonly used when performing diagnostic screening using restriction enzymes. Methods: A total of 126 blood DNA samples were tested in amounts ranging 80-200 ng, referred for the genetic diagnosis of SMA using both conventional PCR-RFLP and allele-specific PCR. Results: The results from both methods showed agreement. Further, allele-specific PCR was found to be a time-efficient and cost-effective method. Interpretation & conclusions: Our study demonstrated the accuracy of our allele-specific PCR and the results were comparable compatible with that of PCR-RFLP, indicating its practical application in SMA diagnostic screening.
Collapse
Affiliation(s)
- M Marini
- Department of Paediatrics, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
| | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Sugumar D, Kong LX, Ismail A, Ravichandran M, Su Yin L. Rapid multi sample DNA amplification using rotary-linear polymerase chain reaction device (PCRDisc). Biomicrofluidics 2012; 6:14119-1411913. [PMID: 22685508 PMCID: PMC3370399 DOI: 10.1063/1.3690469] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 02/09/2012] [Indexed: 05/12/2023]
Abstract
Multiple sample DNA amplification was done by using a novel rotary-linear motion polymerase chain reaction (PCR) device. A simple compact disc was used to create the stationary sample chambers which are individually temperature controlled. The PCR was performed by shuttling the samples to different temperature zones by using a combined rotary-linear movement of the disc. The device was successfully used to amplify up to 12 samples in less than 30 min with a sample volume of 5 μl. A simple spring loaded heater mechanism was introduced to enable good thermal contact between the samples and the heaters. Each of the heater temperatures are controlled by using a simple proportional-integral-derivative pulse width modulation control system. The results show a good improvement in the amplification rate and duration of the samples. The reagent volume used was reduced to nearly 25% of that used in conventional method.
Collapse
|
36
|
Girishkumar MS, Ravichandran M. The influences of ENSO on tropical cyclone activity in the Bay of Bengal during October-December. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jc007417] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
37
|
McPhaden MJ, Foltz GR, Lee T, Murty VSN, Ravichandran M, Vecchi GA, Vialard J, Wiggert JD, Yu L. Ocean-Atmosphere Interactions During Cyclone Nargis. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2009eo070001] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
38
|
Chan M, Gim Cheong T, Kurunathan S, Chandrika M, Ledon T, Fando R, Lalitha P, Zainuddin Z, Ravichandran M. Construction and characterization of an auxotrophic ctxA mutant of O139 Vibrio cholerae. Microb Pathog 2010; 49:211-6. [DOI: 10.1016/j.micpath.2010.06.001] [Citation(s) in RCA: 4] [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] [Received: 03/14/2010] [Revised: 05/25/2010] [Accepted: 06/07/2010] [Indexed: 12/22/2022]
|
39
|
Parampil SR, Gera A, Ravichandran M, Sengupta D. Intraseasonal response of mixed layer temperature and salinity in the Bay of Bengal to heat and freshwater flux. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jc005790] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
40
|
Deris ZZ, Leow VM, Wan Hassan WMN, Nik Lah NAZ, Lee SY, Siti Hawa H, Siti Asma H, Ravichandran M. Non-O1, non-O139 Vibrio cholerae bacteraemia in splenectomised thalassaemic patient from Malaysia. Trop Biomed 2009; 26:320-325. [PMID: 20237446] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Vibrio cholerae infection is mainly caused acute diarrhoea disease. Bacteraemia due to non-O1 V. cholerae is rare and mainly reported in liver cirrhotic patients. We report one case of non-O1 V. cholerae bacteraemia in splenectomised thalassaemic patient who presented with septic shock secondary to abdominal sepsis. She had undergone emergency laporatomy and was managed in the intensive care unit for nine days. She was treated with meropenem and doxycyline and discharged well after fourteen days of admission. The V. cholerae was identified by API 20NE, serotype and polymerase chain reaction showed as non-O1, non-O139 strain. Besides known cholera-like toxin and El Tor hemolysin, with increasing reported cases of V. cholerae bacteraemia, there is possibility of other virulence factors that allow this organism to invade the bloodstream.
Collapse
Affiliation(s)
- Z Z Deris
- Department of Medical Microbiology and Parasitology, School of Medical Sciences, Universiti Sains Malaysia Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia.
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Asmal HS, Mustafa M, Abdullah S, Zaidah AR, Nurhaslindawati AR, Sarimah A, Chan YY, Ravichandran M. Pneumocystis pneumonia among HIV patients in Malaysia. Southeast Asian J Trop Med Public Health 2009; 40:1293-1297. [PMID: 20578464] [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: 05/29/2023]
Abstract
Pneumocystis pneumonia (PCP) has become the most common opportunistic infection in HIV/AIDS patients with a CD4 count < or = 200. The incidence of PCP has declined as a result of prophylaxis and better highly active antiretroviral therapy (HAART). The objective of this study was to review the demographic data of HIV patients diagnosed clinically as having PCP at the Hospital Raja Perempuan Zainab II (HRPZ II) in Malaysia. This was a prospective study. All HIV patients admitted to HRPZ II with respiratory symptoms were enrolled in this study after giving informed consent. Their demographic data were collected. The total number of HIV patients reviewed in this study was 107. Nearly 60% of patients were clinically diagnosed as having pneumocystis pneumonia based on their signs, symptoms and chest x-ray findings. A CD4 count was available in 83 out of 107 patients. The fifty-three percent of patients(44) had a CD4 < 200 and were clinically diagnosed as having pneumocystis pneumonia. Thirty percent had a CD4 < 200 but did not have clinical pneumocystis pneumonia. Sixteen point nine percent had a CD4 > 200 and had clinical pneumocystis pneumonia, three of whom had received HAART, four patients had received prophylaxis. Overall, 94 patients (87.8%) received prophylaxis for pneumocystis pneumonia. Thirty-three patients (30.8%) received HAART. The occurrence of pneumocystis pneumonia was common before full implementation of HAART. Pneumocystis pneumonia can occur in patients with a CD4 >200.
Collapse
Affiliation(s)
- H Siti Asmal
- Department of Medical Microbiology and Parasitology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia.
| | | | | | | | | | | | | | | |
Collapse
|
42
|
Rahman SH, Sengupta D, Ravichandran M. Variability of Indian summer monsoon rainfall in daily data from gauge and satellite. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jd011694] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
43
|
Selvam R, Maheswari P, Kavitha P, Ravichandran M, Sas B, Ramchand CN. Effect of Bacillus subtilis PB6, a natural probiotic on colon mucosal inflammation and plasma cytokines levels in inflammatory bowel disease. Indian J Biochem Biophys 2009; 46:79-85. [PMID: 19374258] [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: 05/27/2023]
Abstract
The pathophysiology of inflammatory bowel disease (IBD) involves the production of diverse lipid mediators, namely eicosanoid, lysophospholipids, and platelet-activating factor, in which phospholipase A2 (PLA2) is the key enzyme. Thus, it has been postulated that control of lipid mediators production by inhibition of PLA2 would be useful for the treatment of IBD. This hypothesis has been tested in the present study by examining the therapeutic effect of a novel natural probitic Bacillus subtilis PB6 (ATCC- PTA 6737). B. subtilis PB6 is found to secrete surfactins (cyclic lipopeptides) which have anti-bacterial potential. These surfactins inhibit PLA2, a rate-limiting enzyme involved in the arachidonic acid associated inflammatory pathway and could downregulate the inflammatory response by regulating the eicosanoid and cytokine pathways. With this concept, an experimental animal trial has been conducted in a rat model of 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. The oral administration of PB6 suppresses the colitis as measured by mortality rate, changes in the weight gain, colon morphology and the levels of plasma cytokines. The animals treated orally with PB6 at 1.5 x 10(8) CFU/kg thrice daily from day 4 to 10 significantly improve gross pathology of the colon and regain the colon weight to normal (p < 0.05), compared to TNBS-induced positive control. The plasma levels of pro-inflammatory cytokines (TNF-alpha, 1L-1beta, IL-6 and IFN-gamma) are also significantly lowered (p < 0.05) and anti-inflammatory cytokine (IL-I0 and TGF-beta) significantly (p < 0.05) increased after the oral administration of PB6 on day 11. The present study supports the concept that PB6 inhibits PLA2 by the secreting surfactins. In a clinical investigation, it is found to be well tolerated by all the healthy volunteers.
Collapse
Affiliation(s)
- R Selvam
- Kemin Industries South Asia (P) Ltd, Plot # K3, 11th Cross Street, SIPCOT Industrial complex, Gummidipoondi, 601 201, Tamil Nadu, India
| | | | | | | | | | | |
Collapse
|
44
|
Tan G, Chan L, Kurunathan S, Atif S, Tan Z, Ravichandran M, Lalitha P. Construction and Functional Evaluation of rtxC and rtxA/C Mutants of O139 Vibrio cholerae. Int J Infect Dis 2008. [DOI: 10.1016/j.ijid.2008.05.436] [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: 11/29/2022] Open
|
45
|
Chua A, Balqis K, Lim B, Ravichandran M, Lalitha P. A Rapid and Simple Dry-Reagent Biosensor for Visual Detection of Amplified DNA Using Microsphere Based Lateral Flow Technology. Int J Infect Dis 2008. [DOI: 10.1016/j.ijid.2008.05.1312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
46
|
Lee S, Chan Y, Elina H, Ravichandran M, Zainul F, Lalitha P. Development of a Thermostabilized Cholera-NASBA-ELISA Assay for the Specific Detection of Vibrio cholerae. Int J Infect Dis 2008. [DOI: 10.1016/j.ijid.2008.05.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
47
|
Chandrika M, Tan G, Nurul Ashikin M, Chan M, Nik Zuraina N, Kurunathan S, Shyamoli M, Ravichandran M, Lalitha P. Construction and Histopathological Characterization of Multiple Virulent Genes Mutant of V. cholerae: To Understand the Enteropathogenesis of Cholera. Int J Infect Dis 2008. [DOI: 10.1016/j.ijid.2008.05.441] [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] Open
|
48
|
Zuraina NN, Atif S, Nurhaslindawathy A, Chan Y, Kurunathan S, Ashikin MN, Lalitha P, Zainul F, Ravichandran M. Cloning and Characterization of hemA Gene of Vibrio cholerae O139. Int J Infect Dis 2008. [DOI: 10.1016/j.ijid.2008.05.586] [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: 10/21/2022] Open
|
49
|
Chan Y, Balqis K, Dilsat A, Lee S, Lalitha P, Ozsoz M, Ravichandran M. Design and Development of a Novel Electrochemical DNA Biosensor for Rapid Molecular Identification of Enterococcus faecium. Int J Infect Dis 2008. [DOI: 10.1016/j.ijid.2008.05.037] [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: 10/21/2022] Open
|
50
|
Gopinath V, Yoong TP, Yean CY, Ravichandran M. Identifying polymorphism in enamelin gene in amelogenesis imperfecta (AI). Arch Oral Biol 2008; 53:937-40. [DOI: 10.1016/j.archoralbio.2008.03.007] [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] [Received: 06/06/2007] [Revised: 10/31/2007] [Accepted: 03/19/2008] [Indexed: 10/22/2022]
|