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Systems Microbiology and Biomanufacturing 2021年第3期1卷 356-361页

作者： Bharti Mishra archana tiwari Diatom Research Laboratory Amity Institute of BiotechnologyAmity UniversityNoidaUttar Pradesh201313India

The pigments are vital parts of photosynthetic machinery in algae and exhibit a myriad of applications as nutraceuticals,cosmetics,colorants,which find huge applications in many industires,including the paint industry and paper *** antimicrobial,antioxidative,anti-inflammatory,and anti-cancer potential of microalgal pigments contribute towards their varied industrial *** this study,pigments(Fucoxanthin,C-phycocyanin,and C-phycoerythrin),extracted from microalgae were investigated to check the antimicrobial efficacy using agar well diffusion and disc diffusion methods against pathogenic bacteria:Staphylococcus aureus and Escherichia *** fucoxanthin pigment isolated from diatom Thalassiosira *** the highest antibacterial activity against Staphylococcus aureus(17±1.53 mm)and in contrast fucoxanthin pigment isolated from Chaetoceroes *** the highest bactericidal activity against Escherichia coli(18±1).The pigment extract of Spirulina plantesis showed the highest antibacterial activity against ***(41±0.3)and *** also exhibited high antibacterial activity against ***(32±0.5)while Anabaena variabilis showed the highest antibacterial activity against Staphylococcus aureus(34±0.5).The potential of microalgal pigments is highly valuable and further extensive studies can elaborate the underlying mechanisms.

关键词： Antimicrobial efficacy Fucoxanthin Microalgae Phycocyanin Phycoerythrin

Correlation between bioactive lipids and novel coronavirus:constructive role of biolipids in curbing infectivity by enveloped viruses,centralizing on EPA and DHA

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Systems Microbiology and Biomanufacturing 2021年第2期1卷 186-192页

作者： Himani Aryan Abhishek Saxena archana tiwari Diatoms Research Laboratory Amity Institute of BiotechnologyAmity UniversityNoidaUttar Pradesh 201301India

Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)belongs to the family *** is spherical and possesses proteins called spikes,which can clamp onto the human *** in close interaction with the human cells,these viruses undergo structural change and can fuse with the cell *** virus enters the host and starts the process of translation and transcription in the cells and uncoated genome,*** to the rapid transmittable nature of the virus,extant actions should be *** fatty acids administrated orally,or intravenously,could help us gear things up in providing resistance and preventing ***,the multiplication of the virus could be hindered by arachidonic acid,eicosapentaenoic acid(EPA),and docosahexaenoic acid(DHA).In that context,the current review highlights the role of these unsaturated fatty acids and their derivatives such as lipoxins and resolvins in the inactivation of the enveloped coro-navirus disease 2019(COVID-19).

关键词： Coronavirus 2 Severe acute respiratory syndrome coronavirus Middle East respiratory syndrome Biolipids Angiotensin-converting enzyme 2 receptor Docosahexaenoic acid Eicosapentaenoic acid

Effect of Iron on Growth, Pigmentation and Antioxidative Activity of Bloom Forming Cyanobacteria

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Journal of Environmental Science and Engineering 2010年第11期4卷 55-64页

作者： archana tiwari Anjana Pandey Nanotechnology and Molecular Biology Laboratory Department of Biotechnology University of AllahabadAllahabad 211002 India

Cyanobacterial blooms are ubiquitous in fresh and brackish eutrophic waters in India. The cyanotoxins produced by many bloom forming cyanobacteria severely affect the health of animals, fishes, birds and human beings. Different physical and chemical factors contribute towards bloom formation. Ten bloom forming cyanobacteria were isolated from natural blooms of northern India. The strains were purified and enriched in the laboratory. The aim of this study was to understand the influence of iron on growth, pigmentation and antioxidative activity of enzymes-catalase and ascorbate peroxidase of bloom forming cyanobacteria. Results show that different strains of bloom forming cyanobacteria attain optimum growth at varied concentration of iron. The cyanobacterial strains like Synechocystis aquatalis, Merismopedia glauca, Anabaena variabilis and Anabaena iyengarii exhibit maximum growth at low iron concentration （2 pM） while some species require higher concentration of iron for their optimum growth namely, Arthrospira platensis show optimum growth at 10uM, and Nostocpaludosum shows maximum growth at 100uM concentration of iron. It was also noticed that chlorophyll and phycobiliprotein content also varies with change in iron concentration. The activity of antioxidative enzymescatalase and ascorbate peroxidase was noticed in all ten cyanobacterial strains. In the light of the findings, it seems that Arthrospira platensis possess maximum catalase and ascorbate peroxidase activity. Increment in concentration beyond optimum value leads to deterioration in the growth, pigment content and enzymatic activity of the cyanobacterial strains. Knowledge about the factors influencing growth of bloom forming cyanobacteria will help to work out ways for eradication of hazardous cyanobacterial blooms.

关键词： Cyanobacterial blooms cyanotoxins phycobiliprotein catalase ascorbate peroxidase.

Comparative Evaluation of Semi Fragile Watermarking Algorithms for Image Authentication

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Journal of Information Security 2012年第3期3卷 189-195页

作者： archana tiwari Manisha Sharma Bhilai Institute of Technology Durg India Chhatrapati Shivaji Institute of Technology Durg India

Technology has no limits today;we have lots of software available in the market by which we can alter any image. People usually copies image from the internet and after some changes they claim that these are their own properties. Insuring digital image integrity has therefore become a major issue. Over the past few years, watermarking has emerged as the leading candidate to solve problems of ownership and content authentications for digital multimedia documents. To protect authenticity of images semi fragile watermarking is very concerned by researchers because of its important function in multimedia content authentication. The aim of this paper is to present a survey and a comparison of emerging techniques for image authentication using semifragile watermarking. In present paper comprehensive overview of insertion and extraction methods used in different semi fragile water marking algorithm are studied using image parameters, potential application, different algorithms are described and focus is on their comparison according to the properties cited above and future directions for developing a better image authentication algorithm are suggested.

关键词： Image Authentication Selective Authentication Content Recovery Robustness Semifragile Watermarking Tamper Detection PSNR

FRIOS Parameters, Key to Reduce Feto-Maternal Mortality in Pre-Eclampsia

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Open Journal of Obstetrics and Gynecology 2014年第6期4卷 321-325页

作者： Amita Sharma archana tiwari Pandey Kiran Agnihotri Meera Department of Biochemistry Amity University Noida India Department of Obstetrics and Gynecology GSVM Kanpur India Department of Obstetrics and Gynecology V. C. S. G. Govt Institute of Medical Sciences & Research Srinagar Garhwal Uttarakhand

Objective(s): To evaluate the role of free radical induced oxidative stress in predicting, prevent and prompt management of pre-eclampsia. Method(s): This prospective study was conducted on 320 pregnant women of which 240 women with pregnancy induced hypertension taken as study group and 80 normal pregnant women were taken as control. Free radical status was evaluated by estimating lipid peroxidation product malonyladehyde and antioxidants-superoxide dismutase, catalase, glutathione reductase. Statistical analysis was done by using SPSS software. Result(s): Pre-eclampsia is significantly associated with free radical induced oxidative stress. Serum level of lipid peroxidation product malondialdehyde increased in pre-eclamptic women. Serum level of antioxidants SuperOxide Dismutase, Catalase level, Glutathione Reductase were reduced. Results are statistically significant. Conclusion(s): Free radical induced oxidative stress is increasing in pre-eclampsia and plays a critical role in etiopathogenesis of pre-eclampsia.

关键词： Free Radical Induced Oxidative Stress (FRIOS) Pre-Eclampsia Malondialdehyde Superoxide Dismutase Catalase Glutathione Reductase

Influence of Three Diatom Aldehydes against the Dengue Vector <i>Aedes aegypti</i>(Diptera: Culicidae)

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American Journal of Plant Sciences 2019年第10期10卷 1749-1762页

作者： Raunak Dhanker archana tiwari Hans-Uwe Dahms Ram Kumar Jiang-Shiou Hwang School of Basic and Applied Sciences GD Goenka University Gurugram India Diatom Research Laboratory Amity University Noida India Department of Biomedical Science and Environmental Biology Kaohsiung Medical University Taiwan Centre for Environmental Sciences Central University of Bihar Patna India Institute of Marine Biology National Taiwan Ocean University Taiwan

Larvae of several mosquito species being vectors of infectious diseases as adults feed on algae in their natural habitat. Algal food comes along with bioactive compounds providing important chemical defenses against predators, competitors, and pathogens. Aedes aegypti (Linnaeus in Hasselquist, 1762) is commonly called yellow fever mosquito, being a vector of several fatal diseases such as dengue fever, zika fever, chikungunya, and yellow fever. In this study, we have investigated the susceptibility of larvae of A. aegypti mosquitos to three most commonly studied diatom aldehydes-2-trans, 4-trans heptadienal (HD), 2-trans, 4-trans octadienal (OD), and 2-trans, 4-trans-decadienal (DD). In the experiments, instar-I and -IV larvae of Ae. aegypti were exposed to above PUAs for different time intervals. Both mosquito instars were susceptible to HD, OD and DD. Instar-I larvae were more susceptible compared to instar-IV. The percentage of mortality of both instar larvae was higher with greater concentrations of each tested PUA. Furthermore, mosquito larvae, tested on DD applied medium was estimated to be more susceptible followed by OD and then by HD. After 24 h observation, LC 50 value was the lowest for DD (0.64 μL/40mL), followed by OD (0.88 μL/40mL) and HD (1.47 μL/40mL) respectively. In current scenarios, our results suggest that natural aldehydes from diatoms could provide promising public health benefits by controlling mosquito vector populations. Furthermore, an in-depth study of the interaction between primary producers and mosquito immatures in nature could provide several advancements in vector control research and management.

关键词： Mosquito Larvicidal Compounds Mosquito Control Diatom Bioactive Compounds Aldehydes Public Health Management

Electromagnetic Expansion and Fragmentation of Hollow Aluminium 5052 Tube

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Journal of Minerals and Materials Characterization and Engineering 2020年第6期8卷 421-439页

作者： Hitesh Choudhary Chiradeep Gupta Nirupama tiwari Tanmay Kolge Rajeev Kapoor archana Sharma Homi Bhabha National Institute Anushaktinagar Mumbai India Accelerator & Pulse Power Division Bhabha Atomic Research Centre Mumbai India Mechanical Metallurgy Division Bhabha Atomic Research Centre Mumbai India Laser & Plasma Technology Division Bhabha Atomic Research Centre Mumbai India

Electromagnetic forming is a high-speed forming technology by which hollow profiles can be compressed or expanded. It is done with a pulsed magnetic field to apply Lorentz’ forces at electrically conductive material. Electromagnetic hollow tube expansion is limited by the fragmentation tendency. This work attempts to use a combination of analytical and computational approach to compute the net tangential stress during tube expansion. A simplified analytical framework to estimate the temporal evolution of plastic stresses present in aluminium alloy AA5052 at low and high applied magnetic pressures is developed based upon dynamic imaging. The time resolved images captured using current synchronised high speed camera record the overall dimensional changes of the tube that is validated by multi-physics simulation of expansion process. Imaging of hollow tube expansions at two selected peak currents has been carried out at various current levels in the range 76 - 160 kA. The direct visualisation of the increase in the tube diameter at two current levels provided a comparison of the developing net tangential stresses in the hollow tube during the undamaged and fragmented expansion. Imaging of tube expansion also facilitates the estimation of the strain rate experienced by the tube and was in the range of ~1700 s-1 to ~1200 s-1. The propensity of fragmentation was found to be due to the level and duration of generated tangential stresses above the yield stress during expansion of the aluminium tubes. Presented study provides a mean of exploiting the enhanced formability of aluminium alloys using electromagnetic forming.

关键词： Electromagnetic Forming Aluminium Alloys High-Speed Imaging