Browsing by Author "Sharma S."

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Detection and prevention of de-authentication attack in real-time scenario
(Blue Eyes Intelligence Engineering and Sciences Publication, 2019) Sharma S.; Mittal M.
Wireless Local Area Network (WLAN) is an infrastructure network in which nodes are connected to a centralized system to provide Internet access to mobile users by radio waves. But WLANs are vulnerable to Medium Access Control (MAC) layer Denial of Service (DoS) attacks due to the susceptibility of the management frames. An attacker can spoof the MAC address of the legitimate client and perform de-authentication attack to disconnect WLANs users from the access point. Many free tools are available in Kali Linux Operating System (OS) by which this attack can be performed and cause a security threat to WLAN users. The consequences of de-authentication DoS attack are frequent disconnection from Internet, traffic redirection, man-in-the-middle attack, and congestion. Despite enormous efforts in combating de-authentication DoS attack in the past decade, this attack is still a serious threat to the security of the cyber world. Medium Access Control Spoof Detection and Prevention (MAC SDP) DoS algorithm performs detection and prevention of de-authentication attack caused by spoofing MAC address. This algorithm is modified to make it more immune to the de-authentication attack and implemented in real-time scenario. The results show that the proposed technique increases the packet flow rate by 20.36%, reduces the packet loss by 95.71%, and reduces the down time and recovery time by 0.39 sec and 0.9 sec respectively as compared to MAC SDP DoS algorithm.
E-pharmacophore guided discovery of pyrazolo[1,5-c]quinazolines as dual inhibitors of topoisomerase-I and histone deacetylase
(Academic Press Inc., 2020) Joshi G.; Kalra S.; Yadav U.P.; Sharma P.; Singh P.K.; Amrutkar S.; Ansari A.J.; Kumar S.; Sharon A.; Sharma S.; Sawant D.M.; Banerjee U.C.; Singh S.; Kumar R.
In the quest to ameliorate the camptothecin (CPT) downsides, we expedite to search for stable non-CPT analogues among 11 motifs of pyrazoloquinazolines reported. E-pharmacophore drug design approach helped filtering out pyrazolo[1,5-c]quinazolines as Topoisomerase I (TopoI) 'interfacial' inhibitors. Three compounds, 3c, 3e, and 3l were shown to be potent non-intercalating inhibitors of TopoI specifically and showed cancer cell-specific cytotoxicity in lung, breast and colon cancer cell lines. The compounds induced cell cycle arrest at S-phase, mitochondrial cell death pathway and modulated oxidative stress in cancer cells. Furthermore, a preliminary study was conducted to explore the feasibility of these compounds to be developed as dual TopoI-HDAC1 (histone deacetylase 1) inhibitors (4a) to combat resistance. Compound 4a was found to possess dual inhibitory capabilities in-vitro. Cytotoxic potential of 4a was found to be significantly higher than parent compound in 2D as well as 3D cancer cell models. Probable binding modes of 4a with TopoI and HDAC1 active sites were examined by molecular modelling.
Geochemical relationship and translocation mechanism of arsenic in rice plants: A case study from health prone south west Punjab, India
(Elsevier B.V., 2020) Sharma S.; Kumar R.; Sahoo P.K.; Mittal S.
Rice is a recognised hyperaccumulator of arsenic (As) and is a serious concern for rice varieties grown in As contaminated soil-water systems. In this regard, groundwater, soil and rice-plant samples (two varieties: PR122 and PUSA1121) collected from 10 sites of district Bathinda were studied for their physicochemical characteristics and As concentration. In vitro studies were carried out to study the role of antioxidant enzymes in As uptake and translocation mechanism. The results showed that the As concentration in water and soil samples ranged from 54 to 132 ?g/L and 6.62–19.56 mg/kg, respectively. The As in rice roots, straw, husk and grains of PR122 ranged from 1.89 to 8.56, 0.20–5.3, 0.12–1.42, 0–0.12 mg/kg, respectively and 1.24–8.16, 0.54–5.11, 0.11–1.06 mg/kg and below detection limit (BDL), respectively for PUSA1121. Although a moderate correlation (r = 0.37) was observed between As in groundwater and soil, the higher As concentration found in both media in Behman and Teona areas indicates that we cannot ignore the role of groundwater in As contamination. Spearman correlation analysis indicates the positive impact of As from groundwater and soil in aerial parts of both rice varieties except grains. In vitro studies showed an increase in antioxidant enzyme activities with the increase in As toxicity (15–60 ?M), which indicates As tolerant behaviour in both rice varieties. The hazard quotient (HQ) for both rice varieties is < 1, which suggest no potential non-cancer health risk, however the cancer risk (CR) for PR122 variety exceeded (2.06 – 10?4) the acceptable limit of 1 × 10?4 (USEPA). Based on the present study, it can be concluded that both the rice varieties are tolerant to As and their grains are safe for human consumption.
Molecular phylogeography of Ficus benghalensis Linnaeus using nrDNA ITS 1, cpDNA trnL and cpDNA rps16 from the Indian subcontinent
(Indian Academy of Sciences, 2019) Sharma S.; Mehra R.; Bast F.
Ficus benghalensis Linnaeus (Moraceae) is the national tree of India and is well known for its pharmacolo-gical properties. The present study was aimed to determine the genetic diversity of F. benghalensis from the Indian subcontinent using sequence-based multi-locus phylogeography. A total of 20 geograph-ical isolates were collected from different regions, cov-ering major parts of its species range within the country. Sequence data from nuclear-encoded internal transcribed spacer region (ITS1), plastid-encoded trnL-F spacer region (trnL) and ribosomal intron re-gion (rps16) were generated. The trnL-based maxi-mum likelihood phylogram revealed the existence of two haplotypes, whereas ITS1 and rps16-based maxi-mum likelihood analysis did not reveal much variation for this species distributed in the Indian subcontinent. These results depict long-distance random gene flow across the subcontinent, and support the post-glacial population contraction events. To validate the impact of palaeo-historic climatic events on current geo-graphic and genetic distribution, species distribution modelling-coupled phylogeography is suggested.