DSpace Repository :: Browsing by Author "Kaur, S"

Browsing by Author "Kaur, S"

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The Alienated Self: Ashima in Jhumpa Lahiri’s The Namesake
(2014) Kaur, S; Sen, R.K.; Pahuja P.
Appraisal of immediate and late effects of mobile phone radiations at 2100 MHz on mitotic activity and DNA integrity in root meristems of Allium cepa
(Springer, 2019) Chandel, S; Kaur, S; Issa, M; Singh, H.P; Batish, D.R; Kohli, R.K.
The present study evaluated the potential of 2100 MHz radiofrequency radiations to act as cytotoxic and genotoxic agent. Fresh onion (Allium cepa L.) roots were exposed to electromagnetic field radiations (EMF-r) for different durations (1 h and 4 h) and evaluated for mitotic index (MI), phase index, chromosomal aberrations, and DNA damage. DNA damage was investigated with the help of the comet assay by assessing various parameters like % head DNA (HDNA), % tail DNA (TDNA), tail moment (TM), and olive tail moment (OTM). Effects of EMF-r exposure were also compared with that of methyl methanesulfonate (MMS; 90 μM), which acted as a positive control. The post-exposure effects of EMF-r after providing the test plants with an acclimatization period of 24 h were also evaluated. Compared to the control, a significant increase in the MI and aberration percentage was recorded upon 4 h of exposure. However, no specific trend of phase index in response to exposure was detected. EMF-r exposure incited DNA damage with a significant decrease in HDNA accompanied by an increase in TDNA upon exposure of 4 h. However, TM and OTM did not change significantly upon exposure as compared to that of control. Analysis of the post-exposure effects of EMF-r did not show any significant change/recovery. Our data, thus, suggest the potential cytotoxic and genotoxic nature of 2100 MHz EMF-r. Our study bears great significance in view of the swiftly emergent EMF-r in the surrounding environment and their potential for inciting aberrations at the chromosomal level, thus posing a genetic hazard. © 2019, Springer-Verlag GmbH Austria, part of Springer Nature.
Energetics and electronic structure of novel hybrid dumbbell monolayers
(American Institute of Physics, 2019) Kaur, S; Singh, J; Kumar, Ashok; Srivastava, S; Tankeshwar, K.
We report three new hybrid monolayers (C6P4, C6N4 and N6P4) of group-IV and group-V elements in dumbbell structure using density functional theory calculations. C6P4, C6N4 possess sp2 as well as sp3 hybridization in their honeycomb dumbbell structure while N6P4 possess only the sp3 hybridization in its non-honeycomb but dumbbell structure. The magnitude of cohesive energy of these hybrid monolayers suggests that C6N4 is the most favorable monolayer to be formed. We found that C6P4 is metallic while C6N4 and N6P4 are semiconductors. Also, we report as a representative case, the systematic structural phase transition from LHD-C to a new phosphorous allotrope which has been suggested to exists in our cohesive energy calculations. The reported monolayers join the family of two dimensional materials and may possess application in nanoelectronic devices. © 2019 Author(s).
Exposure to mobile phone radiations at 2350 MHz incites cyto- and genotoxic effects in root meristems of Allium cepa
(BioMed Central Ltd., 2019) Chandel, S; Kaur, S; Issa, M; Singh, H.P; Batish, D.R; Kohli, R.K.
Background: The exponential increase of electromagnetic field radiations (EMF-r) in the natural environment has raked up the controversies regarding their biological effects. Concern regarding the putative capacity of EMF-r to affect living beings has been growing due to the ongoing elevation in the use of high frequency EMF-r in communication systems, e.g. Mobile phones. Methods: In the present study, we tried to examine the cyto- and genotoxic potential of mobile phone EMF-r at 2350 MHz using onions (Allium cepa L.). Fresh adventitious onion roots were exposed to continuous EMF-r at 2350 MHz for different time periods (1 h, 2 h and 4 h). The evaluation of cytotoxicity was done in terms of mitotic index (MI), phase index and chromosomal aberrations. Genotoxicity was investigated employing comet assay in terms of changes in % HDNA (head DNA) and % TDNA (tail DNA), TM (tail moment) and OTM (olive tail moment). Data were analyzed using one-way ANOVA and mean values were separated using post hoc Tukey's test. Results: The results manifested a significant increase of MI and chromosomal aberrations (%) upon 4 h, and ≥ 2 h of exposure, respectively, as compared to the control. No specific changes in phase index in response to EMF-r exposure were observed. The % HDNA and % TDNA values exhibited significant changes in contrast to that of control upon 2 h and 4 h of exposure, respectively. However, TM and OTM did not change significantly. Conclusions: Our results infer that continuous exposures of radiofrequency EMF-r (2350 MHz) for long durations have a potential of inciting cyto- and genotoxic effects in onion root meristems. © 2019 Springer Nature Switzerland AG.
Indian herbs and their therapeutic potential against Alzheimer’s disease: What makes them special? Neuroprotective Effects of Phytochemicals in Neurological Disorders.
(2016) Kaur, Navrattan; Sarkar, Bibekananda; Gill, Iqbal; Kaur, S; Mittal, Sunil; Dhiman, Monisha; Padala, Prasad R; Perez-Polo ,Regino; Mantha, Anil K.
Land acquisition in Punjab: Jeopardising livelihoods through inefficient implementation
(Economic and Political Weekly, 2020) Kaur, S; Singh, G; Kaur, J; Singh, H.
Analysing a case of development-induced displacement through a survey of land dispossession in Punjab reveals how displacement for development projects adversely affects farmers economically, socially and culturally. Fertile land acquired for a thermal power plant remains unused, depriving villagers of their livelihoods as well as the benefits that could have accrued had the project materialised. Large-scale land acquisition for the establishment of thermal power plants causes irreversible changes in the lives of local communities that are deprived of their source of livelihood by land acquisition and also gives rise to other social, economic, political and ecological changes. To avert the crisis resulting from the acquisition of agricultural land for developmental purposes, "long-term livelihood opportunities" for dispossessed farmers should be rebuilt, as compensation acts as wealth, and not income, for agrarian societies. - 2020 Economic and Political Weekly. All rights reserved.
Novel phosphorus-based 2D allotropes with ultra-high mobility
(Institute of Physics Publishing, 2020) Kaur, S; Kumar, A; Srivastava, S; Tankeshwar, K; Pandey, R.
Electronic structure calculations based on density functional theory were performed to investigate structural, mechanical, and electronic properties of phosphorene-based large honeycomb dumbbell (LHD) hybrid structures and a new phosphorene allotrope, referred to as ??-P. The LHD hybrids (i.e., X6P4; X being C or Si or Ge or Sn) and ??-P have significantly higher bandgaps than the corresponding pristine LHD structures, except the case of C6P4, which is metallic. ??-P is found to be a highly flexible p-type material which shows strain-engineered photocatalytic activity in a highly alkaline medium. The carrier mobility of the considered systems is as high as 105 cm2 V-1 s-1 (specifically the electron mobility of LHD structures). The calculated STM images display the surface morphologies of the LHD hybrids and ??-P. The predicted phosphorus-based 2D structures with novel electronic properties may be candidate materials for nanoscale devices. - 2020 IOP Publishing Ltd.
Phenotypic variations alter the ecological impact of invasive alien species: Lessons from Parthenium hysterophorus
(Academic Press, 2019) Kaur, A; Kaur, S; Singh, H.P; Batish, D.R; Kohli, R.K.
Invasive plant species constantly adjust their behavior with ecological shifts by virtue of phenotypic plasticity and/or local adaptations. Changes in the phenotype of an invasive species may also trigger variations in its community level impacts, which is an acceptable, yet unexplored aspect of invasion biology. Our study attempts to fill important knowledge gaps on the basic behavior and ecological interactions of invasive species. Parthenium hysterophorus, a widely distributed invasive alien species of tropical and sub-tropical regions, was evaluated for variations in its morpho-functional traits and ecological performance at a common spatial and temporal scale. Field surveys were conducted in Chandigarh, India, in five sites identified as invaded with P. hysterophorus. Individuals of P. hysterophorus randomly sampled from these sites, showed from trait analyses that the population is differentiated into two morphotypes, P A and P B . Morphotype P B exhibits traits comparable to the shrub life-form in terms of woody stem (with higher stem circumference [+32.26%], stem specific density [+128.57%], twig dry matter content [+25.15%]); profuse branching (+46.38%); larger canopy (+91.16%); and better reproductive output (+190.29%) compared to P A. P A , on the other hand, reflected herbaceous characteristics with greater leaf area (+67.58%) and higher content of chlorophyll (+21.92%) compared to P B . Based on these morphotypes, the plots were divided into three invasion categories: areas invaded by P A [IP A ], areas invaded by P B [IP B ] and uninvaded areas [UI]. Ecological indices and soil chemical properties were compared across IP A , IP B and UI. Shannon's index (p < 0.001), evenness index (p = 0.008), and richness index (p < 0.001) were significantly lower in IP B compared to IP A . UI areas were found to have higher soil pH, phenolics, organic matter, and concentrations of N, P and K, compared to IP A and IP B , but lower Ca and Mg. Results suggest that phenotypic variations within population of P. hysterophorus regulate its ecological impact on associated vegetation. Conservation managers would benefit from studying its invasion patterns and identifying the morphotype with higher ecological impact to prioritize management efforts. Monitoring these behavioral and ecological patterns in P. hysterophorus over the long-term may also help in anticipating challenges to preventive measures. © 2019 Elsevier Ltd
Phytochemical ginkgolide b protects cultured neuroblastoma SH-SY5Y cells against a?(25-35) induced oxidative stress responses by maintaining the mitochondrial integrity
(Rasayan Journal of Chemistry, c/o Dr. Pratima Sharma, 2020) Kaur, N; Kaur, S; Saini, M; Dhiman, M; Mantha, A.K.
Alzheimer�s disease is associated with oxidative stress induced by accumulation of A? peptide, by disrupting the mitochondrial function. In this study, the oxidative stress responses induced by A?(25-35) and protective effects of diterpenoid phytochemical Ginkgolide B (GB) were evaluated by the determination of cellular oxidant/antioxidant status, oxidative DNA base damage and repair capacity of cells through evaluation of mitochondrial BER pathway status and the multifunctional enzyme APE1 in human neuroblastoma SH-SY5Y cells, and evaluation of mitochondrial membrane potential and changes in apoptotic pathway. It was found that A?(25-35) treatment increased ROS/RNS production, increased the activities of antioxidant SOD and Catalase enzymes, decreased the expression of mitochondrial SOD (SOD2), induced oxidative DNA base damage, might be altered the repair capacity as analyzed by the transcriptional and translational expression of APE1 and other BER pathway enzymes in the mitochondria, disrupted the mitochondrial membrane potential and induced apoptosis as a result of these responses. Phytochemical modulation by the pre-treatment of GB for 3 hr followed by the treatment of A?(25-35) for a period of 24 hr caused decrease in ROS/RNS, increase in activities of antioxidant enzymes and expression of SOD2, decreased oxidative DNA base damage and increased transcriptional and translational expression of APE1, increased/restored expression of APE1 and polymerase gamma (?) in the mitochondria, restored mitochondrial membrane potential and rescued the SH-SY5Y cells from mitochondrial-mediated apoptosis against A?(25-35) induced oxidative stress responses. Taken together, GB showed neuroprotection by restoring cellular antioxidant defense system, repair capacity of cells and restoring mitochondrial integrity (genome and membrane potential), thus rescuing the SH-SY5Y cells from A?(25-35) induced oxidative stress responses. � RAS?YAN. All rights reserved.
Stability and tunable electronic structure of planar phosphorus nanotubes
(American Institute of Physics, 2019) Singh, S; Kaur, S; Gupta, S.K; Kumar, Ashok; Srivastava, S.
The stability and electronic properties of planar phosphorous nanotubes with different chirality are investigated within the formulation of density functional theory. Armchair phosphorous nanotube (APNT) is found to be energetically most favorable with very small formation energy (0.08 eV). APNT also possess highest tensile strength (∼2 GPa), among the considered nanotubes. Armchair and helical PNTs are semiconducting while zigzag PNT is metallic in nature. We found that the application of strain and external electric field greatly modifies the electronic band structure of given PNTs. We believe that planar APNT can be realized and its tunable electronic properties may be useful for nanoelectronics. © 2019 Author(s).
β-Pinene moderates Cr(VI) phytotoxicity by quenching reactive oxygen species and altering antioxidant machinery in maize
(Springer, 2019) Mahajan, P; Singh, H.P; Kaur, S; Batish, D.R; Kohli, R.K.
We examined the possible role of monoterpene β-pinene in providing protection against Cr(VI) toxicity in maize (Zea mays). Treatment with β-pinene (10 μM) significantly alleviated Cr(VI) accumulation and recuperated Cr(VI) caused decline in root and coleoptile growth in maize. β-Pinene addition caused a decline in Cr(VI)-induced accumulation of superoxide anion, hydroxyl ion, hydrogen peroxide and confirmed by in-situ detection of ROS using histochemical localization. It suggested that the β-pinene quenches/neutralizes enhanced ROS generated under Cr(VI) exposure. β-Pinene also reduced Cr(VI)-induced electrolyte leakage, thereby suggesting its role in membrane stabilization. Further, β-pinene regulated the activity of scavenging enzymes, thereby suggesting a role in modulating Cr(VI)-induced oxidative damage. In conclusion, our results suggest that the addition of β-pinene has a protective role against Cr(VI) stress and provides resistance to maize against Cr(VI) toxicity. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.

Browsing by Author "Kaur, S"

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