Browsing by Author "Ashutosh Pandey"

Now showing 1 - 20 of 36

A Narrative Thematic Analysis of the perceived psychological distress and health outcomes in Indian adults during the early phase of the COVID-19 pandemic
(National Documentation Centre, 2023) Gyanesh Kumar Tiwari; Pramod Kumar Rai; Abhigyan Dwivedi; Bablu Ray; Ashutosh Pandey; Rakesh Pandey
COVID-19 represents a severe, novel, and harmful disease that posed worldwide new challenges to the well-being of people and culminated in negative life outcomes. The current study explored the perceived psychological distress and consequent health outcomes caused by COVID-19. The Narrative Thematic Analysis design was employed. Eighteen participants comprising 12 males and 6 females responded about their experiences of the recent outbreak of COVID-19. The data were collected through a telephonic semi-structured interview which was analyzed through the Thematic Analysis Method. Four themes were generated: maladaptive psychological outcomes of COVID-19, perceived poor social support, increased religious practices, and the development of physical health symptoms. Extreme anxiety, panic experiences, insecurity, helplessness, hyper-vigilance, and negative attributions represented the psychological distress, while decreased social interactions and imposed social distancing characterized the perceived social support. Increased reliance on myths, divine interpretations, and faith in God showed religious practices. Decreased hunger, insomnia, headache, breathing problems, and palpitation were some ill-health outcomes. The pandemic shaped the nature and extent of perceived psychological distress, social support, and religious practices. The first two may have caused negative health and well-being outcomes while the religious practices maintained equilibrium among the rest three. Immediate trans-disciplinary efforts for the effective prevention, treatment, and promotion of the affected people are recommended. Positive health practices embedded in different socio-cultural systems may also be explored to help people facing the negative consequences of the recent and future pandemics. The implications and limitations of the study have been discussed. © 2023, Gyanesh Kumar Tiwari, Pramod Kumar Rai, Abhigyan Dwivedi, Bablu Ray, Ashutosh Pandey, Rakesh Pandey Licence CC-BY-SA 4.0.
Alkaline rocks and their economic and geodynamic significance through geological time
(Geological Society of London, 2025) Rohit Pandey; Lukáš Krmíček; Daniel Müller; Ashutosh Pandey; Ciro Cucciniello
Alkaline igneous rocks have a relative excess of alkalis over silica. Most are silica undersaturated and contain normative nepheline and real feldspathoids (nepheline, leucite). Although alkaline rocks make up only about 1% of total igneous rocks by volume, their diverse mineralogy accounts for 90% of all igneous rock names proposed by the IUGS. They occur in all tectonic settings; in the ocean basins and on the continents, along mid-ocean ridges (rare), on oceanic islands, in subduction zones in the oceans and along continental margins, as well as along rift zones. Alkaline rocks commonly include alkali basalts and foidites, tephrites, phonolites, trachytes and their intrusive equivalents, including lamprophyres and carbonatites. In the literature, a plethora of local names for alkaline rocks from different localities have been created and many geoscientists still consider them as petrological curiosities. However, their study can significantly aid the interpretation of mantle evolution, ancient terranes and their geodynamic settings. Additionally, alkaline rocks may host world-class precious- and rare-metal mineralization. During recent years, the exploration interest in critical and rare metal deposits (Nb, rare earth elements (REEs) and Th) has increased dramatically as they represent vital resources for the so-called ‘green energy transition’. This Special Publication presents new comprehensive data, results and findings on alkaline rocks from different terranes worldwide and uses their mineralogy and geochemical fingerprints in order to elucidate their petrogenesis, tectonic settings and mineralization potential. This volume is not only of interest for igneous petrologists, but also for exploration geologists prospecting for precious- and rare-metal mineralization worldwide. © 2025 The Author(s). Published by The Geological Society of London. All rights, including for text and data mining (TDM), artificial intelligence (AI) training, and similar technologies, are reserved. For permissions: https://www.lyellcollection.org/publishing-hub/permissions-policy. Publishing disclaimer: https://www.lyellcollection.org/publishing-hub/publishing-ethics.
Cellular internalization and stress response of ingested amorphous silica nanoparticles in the midgut of Drosophila melanogaster
(2013) Ashutosh Pandey; Swati Chandra; Lalit Kumar Singh Chauhan; Gopeshwar Narayan; Debapratim Kar Chowdhuri
Background: Amorphous silica nanoparticles (aSNPs) are used for various applications including food industry. However, limited in vivo studies are available on absorption/internalization of ingested aSNPs in the midgut cells of an organism. The study aims to examine cellular uptake of aSNPs (< 30 nm) in the midgut of Drosophila melanogaster (Oregon R+) owing to similarities between the midgut tissue of this organism and human and subsequently cellular stress response generated by these nanoparticles. Methods: Third instar larvae of D. melanogaster were exposed orally to 1-100 μg/mL of aSNPs for 12-36 h and oxidative stress (OS), heat shock genes (hsgs), membrane destabilization (Acridine orange/Ethidium Bromide staining), cellular internalization (TEM) and apoptosis endpoints. Results: A significant increase was observed in OS endpoints in the midgut cells of exposed Drosophila in a concentration- and time-dependent manner. Significantly increased expression of hsp70 and hsp22 along with caspases activation, membrane destabilization and mitochondrial membrane potential loss was also observed. TEM analysis showed aSNPs-uptake in the midgut cells of exposed Drosophila via endocytic vesicles and by direct membrane penetration. Conclusion: aSNPs after their internalization in the midgut cells of exposed Drosophila larvae show membrane destabilization along with increased cellular stress and cell death. General significance: Ingested aSNPs show adverse effects on the cells of GI tract of the exposed organism thus their industrial use as a food-additive may raise concern to human health. © 2012 Elsevier B.V. © 2012 Elsevier B.V. All rights reserved.
Coupled Assimilation and Fractional Crystallization (AFC) and Mantle Plume Source(s) Contribution in the Generation of Paleoproterozoic Mafic Dykes of the Eastern Dharwar Craton, Southern India
(Geological Society of India, 2019) Ashutosh Pandey; N.V. Chalapathi Rao
The eastern Dharwar craton (EDC) of the southern Indian Shield hosts five geochronologically distinct Paleoproterozoic mafic dyke swarms emplaced at 2.37, 2.21, 2.18, 2.08 and 1.89 Ga. Trace element geochemical data available for these dykes display the ‘arc signals’ viz., negative Nb-Ta anomalies and elevated Zr/Nb, Th/Yb and Th/Ta values, which are conventionally interpreted to represent involvement of subduction in their genesis. It is shown that these ‘arc signals’ resulted from coupled assimilation and fractional crystallization (AFC) processes that modified these mantle-derived melts. Since, mafic dykes under study are highly evolved, an attempt has been made to estimate (using PRIMELTS2.xls software) the composition of the primary magma from the most primitive sample available from the 2.21 and 2.37 Ga swarms. The mantle potential temperature derived from the estimated primary magma compositions revealed anomalously hot mantle source regions compared to the known ambient upper mantle temperatures during Paleoproterozoic, thus implying the possible involvement of thermal plumes in their genesis. © 2019, Geological Society of India.
Dimensionality and cross-language invariance of Pittsburgh Sleep Quality Index among Indian adolescents and adults
(John Wiley and Sons Inc, 2025) Ashutosh Pandey; Vishnukant Tripathi; Meenakshi Shukla; Rakesh Pandey
Sleep quality, key to physical and mental health, requires regular assessment in clinical and non-clinical settings. Despite widespread use, the dimensionality of the Pittsburgh Sleep Quality Index (PSQI) is debated, and its Hindi version's factor structure remains unexplored. Our study evaluates the PSQI's dimensionality among Indian adolescents and adults aiming to demonstrate cross-language (Hindi and English) invariance of its factor structure. The PSQI showed satisfactory item reliability, and a best-fitting two-factor model: “sleep efficiency” (comprising sleep duration and habitual sleep efficiency), and “perceived sleep quality” (comprising remaining five PSQI components). This model showed configural invariance across age groups, sexes, and languages. Metric invariance was noted across age groups, but a partial metric non-invariance was observed across languages and sexes as reflected by differences in factor loadings. The second-order factor structure model had an excellent fit indicating the usefulness of aggregate scores of the two factors as a single index of sleep quality. Our findings better support a two-factor structure of sleep quality (both for English and Hindi versions of PSQI) in India. However, further validation in diverse clinical and non-clinical samples is warranted. © 2024 European Sleep Research Society.
Efficacy of methuselah gene mutation toward tolerance of dichlorvos exposure in Drosophila melanogaster
(Elsevier Inc., 2015) Ashutosh Pandey; Rehana Khatoon; Sanjay Saini; Divya Vimal; Devendra Kumar Patel; Gopeshwar Narayan; Debapratim Kar Chowdhuri
Adverse reports on the exposure of organisms to dichlorvos (DDVP; an organophosphate insecticide) necessitate studies of organismal resistance/tolerance by way of pharmacological or genetic means. In the context of genetic modulation, a mutation in methuselah (mth; encodes a class II G-protein-coupled receptor (GPCR)) is reported to extend (~35%) the life span of Drosophila melanogaster and enhance their resistance to oxidative stress induced by paraquat exposure (short term, high level). A lack of studies on organismal tolerance of DDVP by genetic modulation prompted us to examine the protective efficacy of mth mutation in exposed Drosophila. Flies were exposed to 1.5 and 15.0 ng/ml DDVP for 12-48 h to examine oxidative stress endpoints and chemical resistance. After prolonged exposure of flies to DDVP, antioxidant enzyme activities, oxidative stress, glutathione content, and locomotor performance were assayed at various days (0, 10, 20, 30, 40, 50) of age. Flies with the mth mutation (mth1) showed improved chemical resistance and rescued redox impairment after acute DDVP exposure. Exposed mth1 flies exhibited improved life span along with enhanced antioxidant enzyme activities and rescued oxidative perturbations and locomotor insufficiency up to middle age (~20 days) over similarly exposed w1118 flies. However, at late (=30 days) age, these benefits were undermined. Further, similarly exposed mth-knockdown flies showed effects similar to those observed in mth1 flies. This study provides evidence of tolerance in organisms carrying a mth mutation against prolonged DDVP exposure and further warrants examination of similar class II GPCR signaling facets toward better organismal health. © 2015 Elsevier Inc.
Endophytic Burkholderia: Multifunctional roles in plant growth promotion and stress tolerance
(Elsevier GmbH, 2022) Gaurav Pal; Samiksha Saxena; Kanchan Kumar; Anand Verma; Pramod K. Sahu; Ashutosh Pandey; James F. White; Satish K. Verma
The genus Burkholderia has proven potential in improving plant performance. In recent decades, a huge diversity of Burkholderia spp. have been reported with diverse capabilities of plant symbiosis which could be harnessed to enhance plant growth and development. Colonization of endophytic Burkholderia spp. have been extensively studied through techniques like advanced microscopy, fluorescent labelling, PCR based assays, etc., and found to be systemically distributed in plants. Thus, use of these biostimulant microbes holds the promise of improving quality and quantity of crops. The endophytic Burkholderia spp. have been found to support plant functions along with boosting nutrient availability, especially under stress. Endophytic Burkholderia spp. improve plant survival against deadly pathogens via mechanisms like competition, induced systemic resistance, and antibiosis. At the same time, they are reported to extend plant tolerance towards multiple abiotic stresses especially drought, salinity, and cold. Several attempts have been made to decipher the potential of Burkholderia spp. by genome mining, and these bacteria have been found to harbour genes for plant symbiosis and for providing multiple benefits to host plants. Characteristics specific for host recognition and nutrient acquisition were confirmed in endophytic Burkholderia by genomics and proteomics-based studies. This could pave the way for harnessing Burkholderia spp. for biotechnological applications like biotransformation, phytoremediation, insecticidal activity, antimicrobials, etc. All these make Burkholderia spp. a promising microbial agent in improving plant performance under multiple adversities. Thus, the present review highlights critical roles of endophytic Burkholderia spp., their colonization, alleviation of biotic and abiotic stresses, biotechnological applications and genomic insights. © 2022 Elsevier GmbH
Enhancing Self-Esteem: Evaluating the Effects of a Self-Affirmation Intervention Among Indian Adults With Subclinical Depression
(John Wiley and Sons Inc, 2025) Gyanesh Kumar Tiwari; Archna Choudhary; Archana Singh; Anurag Shukla; Amit Kumar Macorya; Ashutosh Pandey; Ajit Kumar Singh
Objectives: Previous research reports self-affirmation interventions to be efficacious in enhancing many life outcomes of normal individuals, but limited research has assessed its restorative and preserving capacities to enhance and maintain the self-esteem of individuals with subclinical depressive tendencies. Methods: This study employed an experimental research design. Eighty participants (age range = 22–27 years) with subclinical depression were chosen using purposive sampling and were randomly assigned in equal numbers to the experimental and control conditions and their self-esteem was measured at pre-intervention, post-intervention and follow-up intervals. Results: Results showed that the experimental group participants evoked significantly higher mean scores (F(1, 76) = 29.20, p < 0.001, η2 = 0.28) on self-esteem as compared to the control group at post-intervention (Control: Mean (SD) = 17.48 (2.73); Experimental: Mean (SD) = 51.43 (3.29)) and follow-up (Control: Mean (SD) = 18.28 (2.72); Experimental: Mean (SD) = 48.65 (3.74)). There was a significant difference in the mean scores of the self-esteem of the experimental group participants during post-intervention and follow-up (F(2, 152) = 6.50, p = 0.002, η2 = 0.08). These findings were evident in the conditions' (experimental, control) and intervals' (pre-intervention, post-intervention, follow-up) main and interaction effects: F(2, 152) = 6.54, p < 0.002, η2 = 0.08; and F(2, 152) = 3.87, p < 0.023, η2 = 0.05. The size of these effects ranged from very low, low, to medium (η2). Conclusion: The findings revealed the restorative and preserving capacities of this self-affirmation intervention for self-esteem. The positive outcomes of the self-affirmation intervention may have been produced as result of the activation of meaning, positive cognitions and positive relationships. © 2025 British Association for Counselling and Psychotherapy.
Forgiveness in Later Life: Attributes and Consequences for Older Adults in Indian Families
(Routledge, 2025) Gyanesh Kumar Tiwari; Archana Singh; Archna Choudhary; Anurag Shukla; Amit Kumar Macorya; Ashutosh Pandey; Ajit Kumar Singh
The study explored the nature, attributes, and consequences of forgiveness for the Indian older adults living with their families. Using a qualitative research design, 12 older adults were recruited. The interview transcriptions were analyzed using the thematic analysis method. Results revealed seven themes: forgiveness as a complex process, the significance of the nature of transgressions, the relationship and role of the transgressor, the role of perceived transgressions in the apprehension of conflict, the role of small punishment in forgiveness, the significance of belongingness and good relationship, and role of isolation, withdrawal, and guilt in forgiveness. Participants expressed that forgiveness is reparative and strengthening underlying many positive intrapersonal, interpersonal, and health outcomes. Findings suggested that forgiveness can potentially explicate and uphold relationships and well-being for older adults. © 2025 Taylor & Francis Group, LLC.
Forgiveness of Older Indian Adults Living in Shelter Homes: A Qualitative Study
(Turkish Psychological Counseling and Guidance Association, 2025) Gyanesh Kumar Tiwari; Amit Kumar Macorya; Anurag Shukla; Archna Choudhary; Archana Singh; Ashutosh Pandey; Ajit Kumar Singh
This qualitative study examines the complexities of forgiveness among older Indian adults residing in shelter homes. Using a qualitative design, 18 older adults (10 males and 8 females) with varied educational levels (6 graduates, 10 with higher secondary education, and 2 with secondary education) were recruited through purposive sampling. They responded to semi-structured interview questions. The interviews were audiotaped, transcribed verbatim, and analysed using the thematic analysis method. The thematic analysis revealed seven key themes: the multifaceted nature of forgiveness, the role of severe transgressions, negative cognitions and lack of support, guilt and frequent negative emotional experiences, hindering behaviour patterns, fear of losing respect, and strong adherence to desirable social and religious values in guiding forgiveness practices. Serious offences require significant cognitive and emotional effort, with the nature of the relationship with the perpetrator and their intentions playing crucial roles. Emotional wounds from severe transgressions often create complex barriers to forgiveness, exacerbated by negative cognitions and inadequate support. Loneliness and perceived vulnerability further complicate forgiveness, while ingrained maladaptive behavioural patterns and the fear of losing social respect also impact forgiveness decisions. Strong adherence to social norms and religious beliefs emerged as guiding forces in navigating forgiveness. Encouraging emotional support programmes, cognitive reframing, and community engagement may foster forgiveness among institutionalised older adults. The findings offer a significant understanding of forgiveness in this unique context, emphasising the interplay of cognitive, emotional, social, and cultural factors. © 2025 The Authors. Turkish Journal of Counseling Psychology and Guidance is published by Turkish Psychological Counselling and Guidance Association. This is an article under the terms of the Creative Commons Attribution License. As the original work is properly cited, reproduction in any medium is permitted.
GABA mediated reduction of arsenite toxicity in rice seedling through modulation of fatty acids, stress responsive amino acids and polyamines biosynthesis
(Academic Press, 2019) Navin Kumar; Ambedkar Gautam; Arvind Kumar Dubey; Ruma Ranjan; Ashutosh Pandey; Babita Kumari; Gayatri Singh; Sachin Mandotra; Puneet Singh Chauhan; Saripella Srikrishna; Venkatesh Dutta; Shekhar Mallick
γ-aminobutyric acid (GABA) is a free amino acid, which helps to counteract biotic and abiotic stresses in plants. In the present study, two concentrations of GABA, i.e., 0.5 mM and 1 mM were applied to examine the tolerance of rice seedlings against As(III) (25 µM) toxicity, through the modulations of fatty acids (FAs), stress responsive amino acids (AAs) and polyamines (PAs) biosynthesis. Exogenous GABA (0.5 mM) application significantly reduced the H 2 O 2 and TBARS levels and recovered the growth parameters against As(III) stressed rice seedlings. Simultaneously, co-application of GABA (0.5 and 1 mM) and As(III), consistently enhanced the level of unsaturated fatty acids (USFA) (cis-10-pentadecanoic acid, oleic acid, α-linolenic acid and γ-linolenic acid), which was higher than saturated fatty acid (SFA). Among the USFAs, level of linolenic acid was found to be always higher with GABA application. Similarly, elevated level of AAs (proline, methionine, glutamic acid and cysteine) was also observed with the application of GABA (0.5 and 1 mM) in As(III) stressed seedlings. GABA also enhanced the expression of genes involved in the polyamine synthesis pathway namely arginine decarboxylase (AD), spermine (SPM) and spermidine (SPD) synthase against As(III) treatments, which was higher in roots than in shoots, resulting in enhanced root PAs level. Contrarily, the expression of S-adenosylmethionine decarboxylase (S-AMD) was significantly higher in shoots. Among all the PAs, level of putrescine (PUT) was found to be highest with GABA application. Overall, the study demonstrates that GABA (0.5 mM) at lower concentration plays a vital role in As(III) tolerance by enhancing the biosynthesis of USFA, AA and PA, reducing the level of TBARS and H 2 O 2 in rice seedlings. © 2019 Elsevier Inc.
Kimberlites, lamproites and lamprophyres from the indian shield: Highlights of researches during 2016-2019
(Indian National Science Academy, 2020) N.V. Chalapathi Rao; Rohit K. Giri; Ashutosh Pandey
Highlights of researches on kimberlites, lamproites and lamprophyres (and their entrained xenoliths) during 2016-2019 from the Indian context are presented. A few previously unknown occurrences have been brought to light, and a wealth of petrological, geochemical and isotopic data on these rocks became available. All these studies provided new insights into the nomenclatural as well as geodynamic aspects such as subduction-tectonics, mantle metasomatism, lithospheric thickness, supercontinent amalgamation, and break-up and nature of the sub-continental lithospheric mantle from the Indian shield. © 2020 Indian National Science Academy. All rights reserved.
Lamprophyres from the Indian shield: A review of their occurrence, petrology, tectonomagmatic significance and relationship with the Kimberlites and related rocks
(International Union of Geological Sciences, 2020) N.V. Chalapathi Rao; Rohit Kumar Giri; Abhinay Sharma; Ashutosh Pandey
Lamprophyres are some of the oldest recognized alkaline rocks and have been studied for almost the last 150 years. Known for hosting economic minerals such as gold, diamond and base metals, they are also significant in our understanding of the deep-mantle processes (viz., mantle metasomatism and mantleplume- lithosphere interactions) as well as large-scale geodynamic processes (viz., subduction-tectonics, supercontinent amalgamation and break-up). The Indian shield is a collage of distinct cratonic blocks margined by the mobile belts and manifested by large igneous provinces (LIPs) such as the Deccan. A plethora of lamprophyres, varying in age from the Archaean to the Eocene, with diverse mineralogical and geochemical compositions, are recorded from the Indian shield and played a key role in clarifying the tectonic processes, especially during the Paleo- and Mesoproterozoic and the Late Cretaceous. A comprehensive review of the occurrence, petrology, geochemistry and origin of the Indian lamprophyres is provided here highlighting their tectonomagmatic significance. The relationship of the lamprophyres to the Kimberlite clan rocks (KCRs), focusing on the Indian examples, is also critically examined. © 2020 International Union of Geological Sciences. All rights reserved.
Lithium isotopes in kimberlites, lamproites and lamprophyres as tracers of source components and processes related to supercontinent cycles
(Geological Society of London, 2022) Lukáš Krmícěk; Tomáš Magna; Ashutosh Pandey; N.V. Chalapathi Rao; Jindrǐch Kynický
Our pilot study reveals potential Li isotope fingerprints recorded in the Mesoproterozoic (c. 1.4– 1.1 Ga) kimberlites, lamproites and lamprophyres from the Eastern Dharwar Craton and Paleocene (62 Ma) orangeite from the Bastar Craton in India. The new data are interpreted in the context of available Li isotope composition of lamproitic to lamprophyric rocks occurring in Variscan (Bohemian Massif ) and Alpine–Himalayan (SW Tibet) orogenic belts formed in response to Gondwana–Pangea amalgamation and break-up. As a result of the development of supercontinents, kimberlites from the Eastern Dharwar Craton and ‘orangeite’ from the Bastar Craton show clear presence of a component with a heavy Li isotope signature (δ7 Li up to 9.7‰) similar to ancient altered oceanic crust, whereas the Eastern Dharwar Craton lamproites (2.3–6.3‰) and lamprophyres (3.3–6.7‰) show Li isotope signatures indicative of a dominant contribution from heterogeneous lithospheric mantle. Variscan lamprophyric to lamproitic rocks and post-collisional mantle-derived (ultra)potassic volcanic rocks from SW Tibet, i.e. rocks from the orogenic belts outside the cratonic areas, are characterized by a clear Li isotope shift towards an isotopically lighter component (δ7Li as low as – 9.5‰) comparable with the involvement of evolved continental crust and high-pressure metamorphic rocks in their orogenic mantle source. Such components with isotopically light Li are strikingly missing in the source of cratonic kimberlites, lamproites and lamprophyres. © 2021 The Author(s). Published by The Geological Society of London. All rights reserved.
Lithosphere–asthenosphere interaction and carbonatite metasomatism in the genesis of Mesoproterozoic shoshonitic lamprophyres at Korakkodu, Wajrakarur kimberlite field, Eastern Dharwar Craton, southern India
(John Wiley and Sons Ltd, 2019) Sneha Raghuvanshi; Ashutosh Pandey; Praveer Pankaj; N.V. Chalapathi Rao; Ramananda Chakrabarti; Dinesh Pandit; Rohit Pandey
The spatial and temporal association between lamprophyres and kimberlites provides unique opportunities to explore their genetic relationships. This paper explores such a relationship by detailing mineralogical and geochemical aspects of Korakkodu lamprophyre dykes located within the well-known Mesoproterozoic diamondiferous Wajrakarur Kimberlite field (WKF), towards the south-western margin of Paleo–Mesoproterozoic Cuddapah Basin, Eastern Dharwar Craton, southern India. Mineralogy reveals that these dykes belong to calc-alkaline variety of lamprophyres, but their geochemistry display mixed signals of both alkaline and calc-alkaline lamprophyres. These lamprophyres are highly potassic, and their high Al2O3 and low-TiO2 content implies a shoshonitic character. Low Mg#, Ni, and Cr concentration highlight their evolved nature. High (La/Yb)N and (Gd/Yb)N content is consistent with their derivation from low degrees of partial melting, whereas highly fractionated nature suggests the presence of garnet in their source. Absence of prominent Nb-Ta anomaly implies to the dilution of lithospheric mantle source by melts rich in HFSEs and low La/Nb ratio compared to those of the calc-alkaline island arc volcanics and suggests an asthenospheric overprint on lithospheric mantle source. Carbonatite metasomatism in the source region of these lamprophyres is apparent from conspicuously high-Zr/Hf ratio, and the HFSE budget of these lamprophyres are principally controlled by the presence of phlogopite veins in their lithospheric source. An extremely heterogeneous and layered lithospheric mantle beneath Eastern Dharwar Craton has been inferred from the divergent genetic history of Mesoproterozoic lamprophyres and kimberlites in the Wajrakarur field. © 2019 John Wiley & Sons, Ltd.
Long-term dietary exposure to low concentration of dichloroacetic acid promoted longevity and attenuated cellular and functional declines in aged Drosophila melanogaster
(Kluwer Academic Publishers, 2014) Ashutosh Pandey; Divya Vimal; Swati Chandra; Sanjay Saini; Gopeshwar Narayan; Debapratim Kar Chowdhuri
Dichloroacetic acid (DCA), a water disinfection by-product, has attained emphasis due to its prospect for clinical use against different diseases including cancer along with negative impact on organisms. However, these reports are based on the toxicological as well clinical data using comparatively higher concentrations of DCA without much of environmental relevance. Here, we evaluate cellular as well as organismal effects of DCA at environmentally and mild clinically relevant concentrations (0.02-20.0 μg/ml) using an established model organism, Drosophila melanogaster. Flies were fed on food mixed with test concentrations of DCA for 12-48 h to examine the induction of reactive oxygen species (ROS) generation, oxidative stress (OS), heat shock genes (hsps) and cell death along with organismal responses. We also examined locomotor performance, ROS generation, glutathione (GSH) depletion, expression of GSH-synthesizing genes (gclc and gclm), and hsps at different days (0, 10, 20, 30, 40, 50) of the age in flies after prolonged DCA exposure. We observed mild OS and induction of antioxidant defense system in 20.0 μg/ml DCA-exposed organism after 24 h. After prolonged exposure to DCA, exposed organism exhibited improved survival, elevated expression of hsp27, gclc, and gclm concomitant with lower ROS generation and GSH depletion and improved locomotor performance. Conversely, hsp27 knockdown flies exhibited reversal of the above end points. The study provides evidence for the attenuation of cellular and functional decline in aged Drosophila after prolonged DCA exposure and the effect of hsp27 modulation which further incites studies towards the therapeutic application of DCA. © 2014 American Aging Association.
Mantle transition zone-derived eclogite xenolith entrained in a diamondiferous Mesoproterozoic (∼1.1 Ga) kimberlite from the Eastern Dharwar Craton, India: evidence from a coesite, K-omphacite, and majoritic garnet assemblage
(Cambridge University Press, 2023) Amitava Chatterjee; N.V. Chalapathi Rao; Rohit Pandey; Ashutosh Pandey
Subduction-related kimberlite-borne eclogite xenoliths of the Precambrian age may provide significant information about the evolution and recycling of a subducting crust as exhumed/orogenic eclogites of the pre-Mesoproterozoic time-frame are globally rare. In this paper, we report a kimberlite-borne eclogite xenolith from the diamondiferous Kalyandurg kimberlite cluster of the Eastern Dharwar Craton, India, which contains a plethora of ultra-high-pressure minerals such as coesite, majoritic garnet, and supersilicic K-rich omphacite. The presence of these ultra-high-pressure minerals is confirmed by in situ X-ray diffractometry, laser Raman spectra and electron probe microanalysis. The presence of coesite undisputedly pinpoints a subduction origin for the eclogite at ∼2.8 GPa pressure, which corresponds to ∼100 km depth. The geothermobarometric estimations involving garnet-omphacite-kyanite-coesite reveal that such an eclogitic assemblage equilibrated at ∼5-8 GPa (∼175-280 km) pressure during ultra-deep subduction. The textural relationship between omphacite, coarse-grained garnet and majoritic garnet coupled with the laser Raman spectra and geobarometric estimations obtained from the majoritic garnet demonstrate that the majoritic garnet formed at ∼8-19 GPa (∼280-660 km) owing to disassociation of omphacite and coarse-grained garnet to majoritic garnet during increment of pressure up to the mantle transition zone. Thus, the mineralogical and geothermobarometric data suggest that the studied eclogite possibly travelled down to the mantle transition zone before it was rapidly carried up by a pre-Mesoproterozoic mantle plume, and subsequently entrained as a xenolith by the Mesoproterozoic (∼1.1 Ga) kimberlite. © The Author(s), 2023. Published by Cambridge University Press.
Mesoproterozoic 40Ar/39Ar age and Sr-Nd isotopic geochemistry of calc-alkaline lamprophyre from the Mudigubba area, Eastern Dharwar Craton, India
(Indian Academy of Sciences, 2020) Ashutosh Pandey; N.V. Chalapathi Rao; Ramananda Chakrabarti
We report a 40Ar/39Ar Mesoproterozoic radiometric age for a calc-alkaline lamprophyre dyke from the Mudigubba area towards the western margin of the Cuddapah Basin, Eastern Dharwar Craton (EDC), Southern India. Amphibole phenocryst separates from this lamprophyre yielded a plateau age of 1169 ± 8 Ma (2σ), which is almost 50 million years older than the majority of radiometric dates available for the Wajra-karur field kimberlites which are proximal to this dyke. Bulk-rock Sr-Nd isotopic analyses of the Mudi-gubba lamprophyre dykes (εNd(t) between -13.3 and -12.4) reveal their derivation from an old, enriched, continental lithospheric mantle unlike the kimberlites (bulk-rock and perovskite in situ εNd(t) between -0.77 and +7.93), which originated either from a chondritic or depleted mantle source. This study provides further evidence for emplacement of compositionally distinct, mantle-derived Mesoproterozoic alkaline magmas in the EDC and highlights the extremely heterogeneous character of the lithospheric mantle beneath this craton. © 2020. All rights reserved.
Mineralogical constraints on petrogenesis and tectonic affiliation of Karnaprayag-Rudraprayag metamafics, Garhwal Lesser Himalaya
(Edizioni Nuova Cultura, 2022) Ashutosh Pandey; Deepak Kumar; H.K. Sachan
Widespread Paleoproterozoic metamafic magmatic rocks penecontemporaneous with orthoquartzites occur in the Lesser Himalayan Sequence (LHS). Previous comprehensive geochemical studies on these rocks have highlighted their origin from an enriched continental lithospheric mantle. We present a mineralogical investigation on the metabasalts and metagabbros from the Karnaprayag-Rudraprayag area of the Garhwal LHS to understand substitution mechanisms within various intra-crystalline sites and assess the role of primary magmatic versus post-magmatic processes in their origin. Relict clinopyroxene composition is used to infer the magmatic and tectonic affiliation of these rocks. The silica saturated nature of low-Ti augites is consistent with a calc-alkaline nature and shows compositional resemblance to clinopyroxenes from island arc and mid-oceanic ridge basalts. Edenite exchange is the most dominant substitution mechanism in calcic-amphiboles consistent with their secondary origin. Biotite stoichiometry reveals the predominance of Ti-Tschermak’s and Ferri-Tschermak’s substitutions and their high Fe3+/Fetotal similar to those originated from crustal-derived melts highlight their secondary origin. Anhedral titanites with high Al/Fe (>1.5) mantle ilmenites, which is common in low-grade metamafics. Re-equilibration of ilmenite and Ti-magnetite is interpreted to be a result of oxy-exsolution of primary high temperature ulvӧspinel-magnetite solid solution. Estimated equilibration temperature and logƒO2 of ilmenite-titanomagnetite assemblage range between 436 and 626 °C, and -31.9 to -19.5, respectively approaching FMQ buffer. Such large variation in estimated temperature and logƒO2 is attributed to hydrothermal alteration and low-grade metamorphism. © 2022 Edizioni Nuova Cultura. All rights reserved.
Multi-stage enrichment in the mantle source region of cratonic lamproites: Geochemical and Sr-Nd-Hf-Os isotopic insights from the Mesoproterozoic lamproites of Bastar Craton, India
(Elsevier B.V., 2025) Rohit Pandey; Mahendra Kumar Singh; Ashutosh Pandey; Nittala V. Chalapathi Rao; Boris V. Belyatsky
Deep cratonic mantle-derived magmatic rocks such as lamproites provide significant insights into the composition and evolution of the sub-continental and sub-lithospheric mantle. This study presents SHRIMP U-Pb geochronology of rutile and bulk-rock geochemistry including Sr-Nd-Hf-Os isotopes on lamproite dykes from the diamondiferous Nuapada Lamproite Field (NLF) at the tectonic contact between Bastar Craton and Eastern Ghat Mobile Belt, India. The lamproites sampled from the Darlimunda cluster of NLF exhibit inequigranular-porphyritic texture with phenocrysts of olivine pseudomorphs in a groundmass rich in phlogopite. The abundance of low-temperature secondary phases such as vermiculite, chlorite, and carbonates in these rocks indicate significant post-magmatic alteration. The presence of quartz crystals and micro-veins along with zircon megacrysts indicate crustal assimilation to some extent but a strong enrichment in high-field strength elements buffers against significant crustal contamination. Rutile U-Pb geochronology reveals an emplacement age of 1009 ± 121 Ma, which is consistent with the (i) previously reported whole-rock 40Ar/39Ar age of lamproites from the NLF, and (ii) widespread ∼1.05 Gyr lamproite, kimberlite, and ultramafic lamprophyre magmatism in the Eastern Dharwar and Bastar Cratons, India. Moderate initial 87Sr/86Sr (0.703–0.706) and unradiogenic initial Nd-Hf isotopic (ƐNd of −5.96 to −8.08 and ƐHf of −7.25 to −9.02) composition is similar to the global cratonic lamproites and enriched mantle (EM I type) mantle reservoir. Moderately radiogenic and restricted initial 187Os/188Os (0.189–0.257) with low Os content, unlike that of the kimberlites and sub-continental lithospheric peridotites, show similarity to the Carboniferous orogenic Variscan lamproites from Bohemian massif and Neogene to Quaternary orogenic ultrapotassic mafic rocks from Italian peninsula. Based on the Sr-Nd-Hf-Os isotopic results, we propose that the cratonic lithospheric mantle source of these rocks record the evidence of a long-term enrichment in lithophile elements as a result of an ancient recycled crustal component. Elevated high-field strength elements in the lamproites and kamafugites of the NLF, similar to those of the global cratonic lamproites and ocean island basalts, represent an overprinting of ancient subduction-related metasomatized deep sub-continental lithospheric mantle sources by small-scale carbonatitic melts derived from the convecting sub-lithospheric mantle prior to their melting. Vein-plus-wall-rock mantle as a result of multi-stage mantle enrichment appears to play an important role in the origin of cratonic lamproites. © 2025 Elsevier B.V.