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Assessing combined toxic effects of tetracycline and P25 titanium dioxide nanoparticles using Allium cepa bioassay

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Frontiers of Environmental Science & Engineering 2021年第1期15卷 101-112页

作者： Barsha Roy Khushboo Kadam Suresh Palamadai Krishnan Chandrasekaran natarajan Amitava Mukherjee School of Biosciences and Technology VITVellore 632014India Centre for Nanobiotechnology VITVellore 632014India

Usage of titanium dioxide nanoparticles(TiO_(2) NPs)and tetracycline(TC)has increased significantly in the present *** leads to their release and accumulation in the *** the compounds,individually,can have adverse toxic effects on the *** binary mixtures can increase this degree of *** present study aimed to evaluate the toxicity of both the contaminants in individual and binary mixtures in Allium ***,the toxicity of TiO_(2) NPs upon UVA pre-irradiation was also *** showed that UVA pre-irradiated NPs(UVA-TiO_(2) NPs)had a significant decrease in cell viability than their non-irradiated counterparts(NI-TiO_(2)),denoting an increase in photocatalytic activity upon UVA *** low concentrations of TC(EC10=0.016µmol/L)mixed with TiO2 NPs significantly increased the toxicity for both UVA-TiO_(2) and NI-TiO_(2) *** ROS generation was significantly high for UVA-TiO_(2) ***,TC did not have any effects on ROS *** the compounds exhibited genotoxic potential in *** chromosomal abnormalities like anaphase bridges,telophase bridges,laggard chromosomes,binucleate cells,*** *** binary mixture of UVA-TiO_(2) NPs and TC showed the highest chromosomal aberrations(64.0%±1.26%)than the mixture with NI-TiO_(2) or the individual *** decreased significantly after recovery(46.8%±1.92%),denoting the self-repair *** study proved that UVA-TiO2 NPs were more toxic and could be enhanced further when mixed with a sub-lethal concentration of *** work will help to assess the risk of both compounds in the environment.

关键词： Binary toxicity Cell viability Mitotic index Chromosomal aberration Reactive oxygen species Nanoparticles internalization

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Performance enhancement of futuristic airplanes by nature inspired biomimetic fish scale arrays--A design approach

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Biomimetic Intelligence & Robotics 2022年第2期2卷 32-47页

作者： Ganesh natarajan S Bruce Ralphin Rose J Department of Mechanical Engineering Anna University Regional Campus TirunelveliTamilnaduIndia

Biomimetics has an immense potential to drive the next generation of technologies forward by propounding competent solutions from *** decades,the nonsmooth topography of most living creatures has been critical to their existence and *** to human-made smooth surfaces,when adapted for fluid flow applications,nonsmooth surfaces can enhance the overall aerodynamic performance by reducing the drag ***,the bioinspired scale structure of fish has been identified as a key biomimetic derivative for improving the aerodynamic efficiency in various cross-domain *** study investigates the aerodynamics of a fish scale array(FSA)NACA 0021 model at a specific Reynolds number(Re)of approximately 2.46×105 that is meant for laminar flow conditions using Computational Fluid Dynamics(CFD)tools and a subsonic wind tunnel facility.A 3D printed biomimetic FSA film is developed and affixed on the NACA 0021 wing profile for the experimental investigation,followed by flow visualization through the smoke tunnel *** proved qualitatively under specific aerodynamic conditions,the creation of velocity streaks has a major role in the drag reduction *** obtain a clear perspective of flow across the overlapping fish scale structures,the results are focused on the central and overlapping regions of the FSA *** experiment has proved the existence of a combined formation of low and high velocity streaks in central and overlapping *** FSA 0021 model showed a maximum drag reduction of 9.57%,which was attributed to the streak formation phenomenon observed in the overlapping FSA configuration.

关键词： Biomimetics Aerodynamics Fish scale arrays Drag reduction Bioinspired design

Analysis of EMD Algorithm for Identification and Extraction of An Acoustic Signal in Underwater Channel Against Wind Driven Ambient Noise

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China Ocean Engineering 2014年第5期28卷 645-657页

作者： S.Sakthivel MURUGAN V.natarajan K.MAHESWARAN ECE Department SSN College of Engineering Instrumentation Department MIT Campus Anna University Infosys Chennai India

Sonar generated acoustic signals transmitted in underwater channel for distant communications are affected by numerous factors like ambient noise, making them nonlinear and non-stationary in nature. In recent years, the application of Empirical Mode Decomposition(EMD) technique to analyze nonlinear and non-stationary signals has gained much attention. It is an empirical approach to decompose a signal into a set of oscillatory modes known as intrinsic mode functions(IMFs). In general, Hilbert transform is used in EMD for the identification of oscillatory signals. In this paper a new EMD algorithm is proposed using FFT to identify and extract the acoustic signals available in the underwater channel that are corrupted due to various ambient noises over a range of 100 Hz to 10 kHz in a shallow water region. Data for analysis are collected at a depth of 5 m and 10 m offshore Chennai at the Bay of Bengal. The algorithm is validated for different sets of known and unknown reference signals. It is observed that the proposed EMD algorithm identifies and extracts the reference signals against various ambient noises. Significant SNR improvement is also achieved for underwater acoustic signals.

关键词： EMD IMF SNR ambient noises underwater acoustic signals FFT

Optimization of Performance and Emission Characteristics of PPCCI Engine fuelled with Ethanol and Diesel blends Using Grey-Taguchi Method

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Journal of Thermal Science 2018年第1期27卷 89-94页

作者： S.natarajan K.Pitchandi N.V.Mahalakshmi Department of Mechanical Engineering Sri Venkateswara College of EngineeringSriperumbudur-602117TamilnaduIndia. Department of Mechanical Engineering Sri Venkatcswara College of EngineeringSriperumbudur-602117TamilnaduIndia. Internal combustion Engineering Division Department of Mechanical EngineeringCollege of EngineeringAnna UniversityChennai-600025TamilnaduIndia.

The performance and emission characteristics of a PPCCI engine fuelled with ethanol and diesel blends were car- ded out on a single cylinder air cooled CI engine. In order to achieve the optimal process response with a limited number of experimental cycles, multi objective grey relational analysis had been applied for solving a multiple response optimization problem. Using grey relational grade and signal-to-noise ratio as a performance index, a combination of input parameters was prefigured so as to achieve optimum response characteristics. It was observed that 20% premixed ratio of blend was most suitable for use in a PPCCI engine without significantly affecting the engine performance and emissions characteristics.

关键词： PPCCI Biodiesel Optimization Grey-Taguchi method

In situ formation of bimetallic FeNi nanoparticles on sand through green technology:Application for tetracycline removal

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Frontiers of Environmental Science & Engineering 2020年第1期14卷 185-197页

作者： Ravikumar KVG Debayan Ghosh M rudula Pulimi Chandrasekaran natarajan Amitava Mukherjee Centre for Nanobiotechnology VITVelloreTamil NaduIndia

In this study,FeNi nanoparticles were green synthesized using Punica granatum(pomegranate)peel extract,and these nanoparticles were also formed in situ over quartz sand(GS-FeNi)for removal of tetracycline(TC).Under the optimized operating conditions,(GS-FeNi concentration:1.5%w/v;concentration of TC:20 mg/L;interaction period:180 min),99±0.2%TC removal was achieved in the batch reactor The removaT capacity was 181±1 mg/g.A detailed characterization of the sorbent and the solution before and after the interaction revealed that the removal mechanism(s)involved both the sorption and degradation of *** reusability of reactant was assessed for four cycles of operation,and 77±4%of TC removal was obtained in the *** judge the environmental sustainability of the process,residual toxicity assay of the interacted TC solution was performed with indicator bacteria(Bacillus and Pseudomonas)and algae(Chlorella sp.),which confirmed a substantial decrease in the *** continuous column studies were undertaken in the packed bed reactors using *** the optimized conditions,quite high removal efficiency(978±5 mg/g)was obtained in the *** application of GS-FeNi for antibiotic removal was further evaluated in lake water,tap water,and ground water spiked with TC,and the removal capacity achieved was found to be 781±5,712±5,and 687±3 mg/g,*** work can pave the way for treatment of antibiotics and other pollutants in the reactors using novel green composites prepared from fruit wastes.

关键词： GS-FeNi nanoparticles Tetracycline removal Re-usability Residual toxicity Column studies

Recent advances based on the synergetic effect of adsorption for removal of dyes from waste water using photocatalytic process

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Journal of Environmental Sciences 2018年第3期30卷 201-222页

作者： Subramanian natarajan Hari C.Bajaj Rajesh J.Tayade Inorganic Materials and Catalysis Division (IMCD) CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI)Council of Scientific and Industrial Research (CSIR)

The problem of textile dye pollution has been addressed by various methods,mainly physical,chemical,biological,and *** methods mainly separate and/or remove the dye present in ***,advanced oxidation processes（AOP）have been focused for removal of dye from waste water due to their advantages such as ecofriendly,economic and capable to degrade many dyes or organic pollutant present in *** is one of the advance oxidation processes,mainly carried out under irradiation of light and suitable photocatalytic *** photocatalytic activity of the photocatalytic materials mainly depends on the band gap,surface area,and generation of electron–hole pair for degradation dyes present in *** has been observed that the surface area plays a major role in photocatalytic degradation of dyes,by providing higher surface area,which leads to the higher adsorption of dye molecule on the surface of photocatalyst and enhances the photocatalytic *** present review discusses the synergic effect of adsorption of dyes on the photocatalytic efficiency of various nanostructured high surface area *** addition,it also provides the properties of the water polluting dyes,their mechanism and various photocatalytic materials;and their morphology used for the dye degradation under irradiation of light along with the future prospects of highly adsorptive photocatalytic material and their application in photocatalytic removal of dye from waste water.

关键词： Photocatalysis Dye degradation Adsorption Water pollution Advanced oxidation processes Nanomaterials

Evolution of fracture permeability due to co-colloidal bacterial transport in a coupled fracture-skin-matrix system

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Geoscience Frontiers 2012年第4期3卷 503-514页

作者： N.natarajan G.Suresh Kumar EWRE Division Department of Civil EngineeringIndian Institute of TechnologyMadrasChennai 600036India Department of Ocean Engineering Indian Institute of TechnologyMadrasChennai 600036India

A numerical model is developed for investigating the evolution of fracture permeability in a coupled fracture-matrix system in the presence of fracture-skin with simultaneous colloidal and bacte- rial transport, by taking into account the effects of thermal stress and silica precipitation/dissolution, which is computed using linear reaction kinetics. The non-linear coupled equations are numerically modeled using the fully implicit finite difference method and a constant continuous source is adopted while modeling thermal, contaminant, colloidal and bacterial transport. Due to co-colloid bacterial trans- port under non-isothermal conditions, in a coupled fracture-skin-matrix system, the fracture apertures vary spatially, with a corresponding pressure variation for a constant discharge. A series of numerical experiments were conducted for analyzing the spatial variation of fracture aperture in response to the combined effects of thermal stress, silica precipitation/dissolution, and simultaneous colloidal and bacte- rial transport in the presence of the fracture-skin. The simulation results suggest that temperature and contaminant concentration of the mobile fluid within the fracture increases with reduction in initial frac- ture aperture. The pattern of variation followed by the fracture aperture is nearly the same in the presence and absence of bacterial transport but the magnitude of the fracture aperture is low under the influence of bacterial transport. The variation in the fracture aperture resulting from precipitation-dissolution and thermoelastic stress is significant when the fracture aperture is very low and reduces with increment in fracture aperture. The variation in fracture aperture and pressure remains the same for both undersaturated and supersaturated fluid entering the fracture due to the influence of bacterial transport at the inlet of the fracture.

关键词： Bacterial transport Colloidal transport Fracture permeability Fracture skin Precipitation-dissolution

Towards enriching and isolation of uncultivated archaea from marine sediments using a refined combination of conventional microbial cultivation methods

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Marine Life Science & Technology 2021年第2期3卷 231-242页

作者： Haining Hu Vengadesh Perumal natarajan Fengping Wang State Key Laboratory of Microbial Metabolism School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghai200240China School of Oceanography Shanghai Jiao Tong UniversityShanghai200240China

The archaea that can be readily cultivated in the laboratory are only a small fraction of the total diversity that exists in *** molecular ecology methods,such as metagenomic sequencing,can provide valuable information independent of cell cultivation,it is only through cultivation-based experiments that they may be fully characterized,both for their physiological and ecological ***,we report our efforts towards enriching and isolation of uncultivated archaea from marine sediments using a refined combination of conventional microbial cultivation ***,cells were retrieved from the sediment samples through a cell extraction procedure and the sediment-free mixed cells were then divided into different size-range fractions by successive filtration through 0.8µm,0.6µm and 0.2µm *** 16S rRNA gene analyses indicated noticeable retention of different archaeal groups in different *** each fraction,supplementation with a variety of defined substrates(e.g.,methane,sulfate,and lignin)and stepwise dilutions led to highly active enrichment cultures of several archaeal groups with Bathyarchaeota most prominently ***,using a roll-bottle technique,three co-cultures consisting of Bathyarchaeota(subgroup-8)and a bacterial species affiliated with either Pseudomonas or Glutamicibacter were *** results demonstrate that a combination of cell extraction,size fractionation,and roll-bottle isolation methods could be a useful protocol for the successful enrichment and isolation of numerous slow-growing archaeal groups from marine sediments.

关键词： Microbial cultivation Marine sediments Uncultivated archaea Co-culture Bathyarchaeota

In vitro biofilm formation by uropathogenic Escherichia coli and their antimicrobial susceptibility pattern

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Asian Pacific Journal of Tropical Medicine 2012年第3期5卷 210-213页

作者： Poovendran Ponnusamy Vidhya natarajan Murugan Sevanan Department of Microbiology Dr.N.G.P Arts and Science CollegeCoimbatore-641048Tamil NaduIndia Department of Biotechnology School of Biotechnology and Health SciencesKarunya UniversityCoimbatore-641114Tamil NaduIndia

Objective:To detect in vitro biofilm formation of uropathogenic Escherichia coli(***)(UPEC) strains isolated from urine specimens and also to determine their antimicrobial susceptibility pattern using 13 commonly used ***:The present study comprised of 166 urine specimens collected from tertiary care hospitals in and around *** India. All the specimens were subjected to gram staining,bacterial culture and the *** strains were screened for biofilm formation using Tube Method(TM),Congo Red Agar(CRA) and Tissue Culture Plate method(TCP) ***,the antimicrobial susceptibility test was performed by Kirby Bauer-disk diffusion method for the biofilm and non-biofilm producing E. coli ***:Of the 100(60.2%) *** strains,72 strains displayed a biofilm positive phenotype under the optimized conditions in the Tube Method and the strains were classified as highly positive(17,23.6%),moderate positive(19.26.3%) and weakly positive(36.50.0%). similarly under the optimized conditions on Congo Red agar medium,biofilm positive phenotype strains were classified as highly positive(23,23%).moderate positive(37.37%) and weakly positive(40,40%).While in TCP method,the biofilm positive phenotype strains were also classified as highly positive(6.6%),moderate positive(80.80%) and weakly positive(14,14%),it didn’t not correlate well with the tube method for detecting biofilm formation in *** rates of antibiotic resistance of biofilm producing *** were found to be 100%for chloramphenicol and amoxyclav(amoxicillin and clavulanic acid),86%for gentamicin and cefotaxime.84%for ceftazidime,83%for cotrimoxazole and piperacillin/tazobactam,75%for tetracycline and 70% for amikacin,Conclusions:This study reveals the prevalence and antimicrobial susceptibility pattern of biofilm and non-biofilm producing uropathogenic *** strains.

关键词： Urinary tract infection Escherichia coli biofilm Multi-drug resistance