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In vitro Antioxidant Activity of Ethanolic Extract of Chlorophytum borivilianum
R. Govindarajan1,,N. Sreevidya1,,M. Vijayakumar1,,M. Thakur2,,V.K. Dixit2,,S. Mehrotra*1,,P. Pushpangadan1 한국생약학회 2005 Natural Product Sciences Vol.11 No.3
Chlorophytum borivilianum Baker (Antharicaceae) comonly referred as ‘Safed Musli’ has beenwidely used in the Indian traditional systems of medicine to treat various diseases like rheumatism apart fromaphordisiac properties. C. borivilianum was screened for the first time to determine its antioxidant activity,isolation of the sapogenins and standardization of the isolated sapogenin fraction using HPTLC. Potent antioxidantactivity of ethanolic extract was found by their ability to scavenge DPPH (84.51%), hydroxyl radical (48.95 %),feryl bi-pyridyl complex (84.53%) along with the inhibition of lipid peroxidation (67.17%) at 100g/mlconcentration. The ethanolic extract also exhibited significant inhibition of superoxide anion radical generated byplant in the traditional system especially its use as a Rasayana drug.
A Novel Jamming Detection Technique for Wireless Sensor Networks
( K. P. Vijayakumar ),( P. Ganeshkumar ),( M. Anandaraj ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.10
A novel jamming detection technique to detect the presence of jamming in the downstream direction for cluster based wireless sensor networks is proposed in this paper. The proposed technique is deployed in base station and in cluster heads. The proposed technique is novel in two aspects: Firstly, whenever a cluster head receives a packet it verifies whether the source node is legitimate node or new node. Secondly if a source node is declared as new node in the first step, then this technique observes the behavior of the new node to find whether the new node is legitimate node or jammed node. In order to monitor the behavior of the existing node and new node, the second step uses two metrics namely packet delivery ratio (PDR) and received signal strength indicator (RSSI). The rationality of using PDR and RSSI is presented by performing statistical test. PDR and RSSI of every member in the cluster is measured and assessed by the cluster head. And finally the cluster head determines whether the members of the cluster are jammed or not. The CH can detect the presence of jamming in the cluster at member level. The base station can detect the presence of jamming in the wireless sensor network at CH level. The simulation result shows that the proposed technique performs extremely well and achieves jamming detection rate as high as 99.85%.
( Vijayakumar M. Malathi ),( Ravi P. More ),( Rangasamy Anandham ),( Gandhi R. Gracy ),( Muthugounder Mohan ),( Thiruvengadam Venkatesan ),( Sandipan Samaddar ),( Sushil K. Jalali ),( Tongmin Sa ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.6
Knowledge about the gut bacterial communities associated with insects is essential to understand their roles in the physiology of the host. In the present study, the gut bacterial communities of a laboratory-reared insecticide-susceptible (IS), and a field-collected insecticide-resistant (IR) population of a major rice pest, the brown planthopper Nilaparvata lugens, were evaluated. The deep-sequencing analysis of the V3 hypervariable region of the 16S rRNA gene was performed using Illumina and the sequence data were processed using QIIME. The toxicological bioassays showed that compared with the IS population, IR population exhibited 7.9-, 6.7-, 14.8-, and 18.7-fold resistance to acephate, imidacloprid, thiamethoxam, and buprofezin, respectively. The analysis of the alpha diversity indicated a higher bacterial diversity and richness associated with the IR population. The dominant phylum in the IS population was Proteobacteria (99.86%), whereas the IR population consisted of Firmicutes (46.06%), followed by Bacteroidetes (30.8%) and Proteobacteria (15.49%). Morganella, Weissella, and Enterococcus were among the genera shared between the two populations and might form the core bacteria associated with N. lugens. The taxonomic-tophenotypic mapping revealed the presence of ammonia oxidizers, nitrogen fixers, sulfur oxidizers and reducers, xylan degraders, and aromatic hydrocarbon degraders in the metagenome of N. lugens. Interestingly, the IR population was found to be enriched with bacteria involved in detoxification functions. The results obtained in this study provide a basis for future studies elucidating the roles of the gut bacteria in the insecticide resistance-associated symbiotic relationship and on the design of novel strategies for the management of N. lugens.
K.N. Sharafudeen,A. Adithya,S. Vijayakumar,P. Sudheesh,B. Kalluraya,K. Chandrasekharan 한국물리학회 2011 Current Applied Physics Vol.11 No.4
The nonlinear optical characteristics of some organic materials namely coumarin derivatives [3-[(2E)-3-phenylprop-2-enoyl]-2H-chromen-2-one(Cm1) and 3-{(2E)-3-[4-(dimethylamino)phenyl]prop-2-enoyl}-2H-chromen-2-one (Cm2)] doped in a polymer matrix of polymethylmethacrylate (PMMA) have been studied. The Z-scan study on these composite films reveals that the compounds exhibit a self-focusing effect at 532 nm. The nonlinear absorption coefficient, nonlinear refractive index and second-order molecular hyperpolarizability are measured. The optical power limiting experiment is carried out and it is attributed to reverse saturable absorption due to excited state absorption in the samples. This article also reports the enhancement of third-order nonlinearity by substituting with an electron donor group and hence establishes the electronic nature of nonlinearity.
Paulsamy, S.,Vijayakumar, K.K.,Kil, Bong-Seop,Senthilkumar, P. The Ecological Society of Korea 2009 Journal of Ecology and Environment Vol.32 No.4
The rare endemic plant, Smilax wightii, is generally distributed in shola forests at high altitudes in Nilgiri Biosphere Reserve, the Western Ghats, southern India. To determine the ecological status of the species, we surveyed 11 major shola forests in that region. S. wightii has a limited distribution in all sholas (frequency value of < 13%). The density of the species is generally around $15/100\;m^2$ in the sholas except in Thiashola where it occurred at a density of 40 individuals/$100\;m^2$. The density of S. wightii was generally greater in the margins of the shoals, while the interior forests contained fewer individuals per unit area. The basal cover occupied by this species ranged between 2246 and $3144\;mm^2/100\;m^2$. The importance value index for S. wightii was >2 in all shoals, which indicates that the species occupies an important position in the lower stratum of shola forests of Nilgiri Biosphere Reserve.
S. Paulsamy,길봉섭,K.K. Vijayakumar,P. Senthilkumar 한국생태학회 2009 Journal of Ecology and Environment Vol.32 No.4
The rare endemic plant, Smilax wightii, is generally distributed in shola forests at high altitudes in Nilgiri Biosphere Reserve, the Western Ghats, southern India. To determine the ecological status of the species, we surveyed 11 major shola forests in that region. S. wightii has a limited distribution in all sholas (frequency value of <13%). The density of the species is generally around 15/100 m² in the sholas except in Thiashola where it occurred at a density of 40 individuals/100 m². The density of S. wightii was generally greater in the margins of the shoals, while the interior forests contained fewer individuals per unit area. The basal cover occupied by this species ranged between 2246 and 3144 mm²/100 m². The importance value index for S. wightii was >2 in all shoals, which indicates that the species occupies an important position in the lower stratum of shola forests of Nilgiri Biosphere Reserve.