Pradeep Srivastava | University of Allahabad (original) (raw)

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Papers by Pradeep Srivastava

Research paper thumbnail of Lycopene prevents sugar-induced morphological changes and modulates antioxidant status of human lens epithelial cells

British Journal of Nutrition, 2002

Cataract is a multifactorial disease. Osmotic stress, together with weakened antioxidant defence ... more Cataract is a multifactorial disease. Osmotic stress, together with weakened antioxidant defence mechanisms, is attributed to the changes observed in human diabetic cataract. Epidemiological studies provide evidence that nutritional antioxidants slow down the progression of cataract. The usefulness of lycopene, a dietary carotenoid, in the pathogenesis of human cataracts has not been studied so far. Since the epithelium is the metabolic unit of the lens, the effect of lycopene on galactose-induced morphological changes and antioxidant status of human lens epithelial cells (HLEC) in culture was evaluated in the present study. HLEC of fresh cadaver eyes obtained from an eye bank were cultured in medium supplemented with fetal calf serum (200 ml/l). On confluency, the cells were subcultured in medium containing either 30 m-d-galactose or 30 mM-d-galactose + lycopene (5, 10 or 20 μM) for 72 h. The cells were observed under the phase-contrast microscope and transmssion electron microscop...

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Research paper thumbnail of Combined 3D QSAR Based Virtual Screening and Molecular Docking Study of Some Selected PDK-1 Kinase Inhibitors

Journal of Computational Medicine, 2014

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Research paper thumbnail of Depositional environment and OSL chronology of the Homeb silt deposits, Kuiseb River, Namibia

Previous studies suggest that the Homeb silts of the Kuiseb valley, Namibia (i) accumulated in a ... more Previous studies suggest that the Homeb silts of the Kuiseb valley, Namibia (i) accumulated in a dune-dammed lake, (ii) are end-point deposits, (iii) represent an aggrading river bed, and (iv) are slackwater deposits. Thus, they have been used alternatively as evidence of past ...

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Research paper thumbnail of Fashion and phases of late Pleistocene aggradation and incision in the Alaknanda River Valley, western Himalaya, India

Quaternary Research, 2008

We study the aggradation and incision of the Alaknanda River Valley during the late Pleistocene a... more We study the aggradation and incision of the Alaknanda River Valley during the late Pleistocene and Holocene. The morphostratigraphy in the river valley at Deoprayag shows the active riverbed, a cut terrace, and a fill terrace. The sedimentary fabric of the fill terrace comprises four lithofacies representing 1) riverbed accretion, 2) locally derived debris fan, 3) the deposits of waning

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Research paper thumbnail of GPR and neotectonic studies in the lower Alaknanda valley-Lesser Garhwal Himalaya: Implications to Mountain building

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Research paper thumbnail of Lake Ziro: A Transient sedimentary storage and palaeoclimate archive in Lesser NE Himalaya

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Research paper thumbnail of Tectono-climatic signatures in NW Himalaya during Quaternary period in Spiti valley

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Research paper thumbnail of Geochemistry of Lesser Himalayan terraces and implication to the sediment generation processes in the Himalaya

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Research paper thumbnail of Widespread aggradation in Alaknanda River: response of Climate change and Tectonics

ABSTRACT The Alaknanda River flows orthogonally to the major and minor litho-tectonic discontinui... more ABSTRACT The Alaknanda River flows orthogonally to the major and minor litho-tectonic discontinuities of Himalaya. The drainage network of the river traverses through the climatic gradients ranging from 1200 mm/year at the foothills to ~3000 mm/year near the mountain front of Higher Himalaya. Thus these fluvial terraces preserve a composite record of 1) regional variations in climate, 2) local and regional tectonics. A morpho-tectonic navigation along Alaknanda valley between Rudraprayag and Karanprayag shows various levels of fluvial terraces, fossil valleys and epigenetic gorges that reflect the effect of past Tectono-climatic pulsations. In this segment the river runs parallel to the Alaknanda fault where the terrace configuration suggests that at least two major phases of rapid aggradation and bedrock incision/uplift are preserved. The terrace configuration at Gholtir show three levels of cut and fill fluvial terraces namely T1, T2 and T3 with bedrock being exposed at the base of T1. At Nagrasu two fossil valleys are observed at two different levels marking the two phases of rapid fluvial aggradation and bedrock incision and uplift. At Gaucher there are five levels of terraces, namely, T1 and T2, which are cut and fill type with bedrock at the base of T1. Further the older terraces T3-T5 are second set of cut and fill terrace sequence with bedrock at the base of T3 again suggesting two phases of valley aggradation and bedrock incision. Similarly at Bamoth two levels of cut and fill terraces are observed. The common observation at all location is northward shift of river channel probably linked with the activity of Alaknanda fault. Optically Stimulated Luminescence (OSL) chronology of the fluvial fill suggested that the aggradational phases were focused at Oxygen Isotope Stage- 3 (OIS-3) and during the transition of OIS-2 and OIS-1. The latest phase of incision in Alaknanda River took place in response to enhanced precipitation after the Last Glacial Phase between 12-10 ka. Similar conclusion from the studies elsewhere (Srivastava et al. 2008a and b; Choudhary et al., 2008) suggest that the phenomenon of Alaknanda aggradation responded to Global climatic changes where the activity along the local thrust and faults created accommodation space by laterally and vertically shifting the channel during the Late Pleistocene-Holocene.

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Research paper thumbnail of Last 20 ka of Himalayan Rivers: oscillations in-phase with global climatic changes

ABSTRACT Himalayan orogen, one of the highest continental relief, experiences a significant E-W r... more ABSTRACT Himalayan orogen, one of the highest continental relief, experiences a significant E-W rainfall gradient, houses several erosional hotspots, bears potential to change the chemical and sedimentary architecture of oceans globally. The river systems that drain through these mountains respond to continental scale epirogenic forces and to global climatic forcing. The resultant of this interaction decides upon the large-scale Morphotectonic development of the Himalaya and its foreland (Srivastava et al. 2003; Wobus et al. 2005). During the last 20 ka the rivers in Himalaya and adjoining continents have witnessed significant climatic changes ranging from widespread glaciation during the ~21-18 ka and followed by significant retreat and strengthened monsoon. This led to major shift in the hydrological regime of the rivers draining the Himalayas. An initiative, combining field investigations and chronological studies on the geomorphological and sedimentological archives of major Himalayan river valleys of (i) Spiti (Arid-Trans-Himalaya, rainfall ~100 mm/a), (ii) Mandakini, Alaknanda, Bhagirathi (NW Lesser Himalaya, rainfall ~1200 mm/a, Srivastava et al. 2008a), (iii) Marsyandi (Humid, Central Himalaya, Nepal, rainfall 2000 mm/a, Pratt et al. 2004), (iv) Teesta (Eastern Himalaya, Sikkim, Rainfall ~2500 mm/a, Mukul et al. 2007) (v) Kameng and Brahmaputra (NE Himalaya, rainfall ~3000 mm/a; Srivastava et al. 2008b; Srivastava and Misra 2008) indicated that: � The River valleys in terms of aggradation and incision oscillated in-phase with the changing climate during the last 20 ka. The climatic transition from the last glacial phase to rainfall Maxima of Holocene was characterized by large-scale valley aggradations. The Spiti River showed deviation conforming to present day rainfall conditions. The wetter conditions of the early Holocene led to increased stream power and river incision. � The rivers in NE Himalaya exhibit several phases of incision that are synchronous to aggradation in west. This is due to relatively high rainfall in the region that did not reduce below a threshold even during the drier phases of Last Glacial phase. This points towards relatively high erosional stress and associated deformation in the NE Himalaya. � The catchments in the Ganga plain responded asynchronously with their Himalayan counterparts where the significantly decreased stream power owes responsibility. � Complete evacuation and mass removal via Himalayan rivers occurs only during wetter conditions and therefore the spanning of the drier and wetter conditions should govern the degree and phases of deformation in the mountain chain like Himalaya.

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Research paper thumbnail of SPECIAL ISSUE Mountain Building and Climate-Tectonic Interaction (MBCT-2008) PREFACE

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Research paper thumbnail of River systems in Himalaya: looking into the past through the luminescence dating technique

Himalaya, the expression of continent-continent collision and related thrust tectonics, shows hig... more Himalaya, the expression of continent-continent collision and related thrust tectonics, shows highest continental relief, experiences a significant EW rainfall gradient and variations in surface processes. In an active orogen of such a kind, mass distribution, erosion, intensity of ...

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Research paper thumbnail of Past changes in sediment dynamics in the Himalayas inferred from uranium-series isotopes

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Research paper thumbnail of A future big one in the North-West Himalayan syntax?

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Research paper thumbnail of Response of the rivers in Himalaya to Late Pleistocene-Holocene climate and neotectonic evolution of the orogeny

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Research paper thumbnail of Climatic control on erosion in the Himalayas over the past 40 ka

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Research paper thumbnail of Elemental Behaviour in the Soil Profile of the Humid Northeastern Himalaya

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Research paper thumbnail of Late quaternary landform evolution along the Indus River, Ladakh, NW Himalaya

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Research paper thumbnail of Early Holocene monsoonal fluctuations in the Garhwal higher Himalaya as inferred from multi-proxy data from the Malari paleolake

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Research paper thumbnail of synchronicity Late Quaternary glacial advances in the Tons River Valley, Garhwal Himalaya, India and regional

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Research paper thumbnail of Lycopene prevents sugar-induced morphological changes and modulates antioxidant status of human lens epithelial cells

British Journal of Nutrition, 2002

Cataract is a multifactorial disease. Osmotic stress, together with weakened antioxidant defence ... more Cataract is a multifactorial disease. Osmotic stress, together with weakened antioxidant defence mechanisms, is attributed to the changes observed in human diabetic cataract. Epidemiological studies provide evidence that nutritional antioxidants slow down the progression of cataract. The usefulness of lycopene, a dietary carotenoid, in the pathogenesis of human cataracts has not been studied so far. Since the epithelium is the metabolic unit of the lens, the effect of lycopene on galactose-induced morphological changes and antioxidant status of human lens epithelial cells (HLEC) in culture was evaluated in the present study. HLEC of fresh cadaver eyes obtained from an eye bank were cultured in medium supplemented with fetal calf serum (200 ml/l). On confluency, the cells were subcultured in medium containing either 30 m-d-galactose or 30 mM-d-galactose + lycopene (5, 10 or 20 μM) for 72 h. The cells were observed under the phase-contrast microscope and transmssion electron microscop...

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Research paper thumbnail of Combined 3D QSAR Based Virtual Screening and Molecular Docking Study of Some Selected PDK-1 Kinase Inhibitors

Journal of Computational Medicine, 2014

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Research paper thumbnail of Depositional environment and OSL chronology of the Homeb silt deposits, Kuiseb River, Namibia

Previous studies suggest that the Homeb silts of the Kuiseb valley, Namibia (i) accumulated in a ... more Previous studies suggest that the Homeb silts of the Kuiseb valley, Namibia (i) accumulated in a dune-dammed lake, (ii) are end-point deposits, (iii) represent an aggrading river bed, and (iv) are slackwater deposits. Thus, they have been used alternatively as evidence of past ...

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Research paper thumbnail of Fashion and phases of late Pleistocene aggradation and incision in the Alaknanda River Valley, western Himalaya, India

Quaternary Research, 2008

We study the aggradation and incision of the Alaknanda River Valley during the late Pleistocene a... more We study the aggradation and incision of the Alaknanda River Valley during the late Pleistocene and Holocene. The morphostratigraphy in the river valley at Deoprayag shows the active riverbed, a cut terrace, and a fill terrace. The sedimentary fabric of the fill terrace comprises four lithofacies representing 1) riverbed accretion, 2) locally derived debris fan, 3) the deposits of waning

Bookmarks Related papers MentionsView impact

Research paper thumbnail of GPR and neotectonic studies in the lower Alaknanda valley-Lesser Garhwal Himalaya: Implications to Mountain building

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Lake Ziro: A Transient sedimentary storage and palaeoclimate archive in Lesser NE Himalaya

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Tectono-climatic signatures in NW Himalaya during Quaternary period in Spiti valley

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Geochemistry of Lesser Himalayan terraces and implication to the sediment generation processes in the Himalaya

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Widespread aggradation in Alaknanda River: response of Climate change and Tectonics

ABSTRACT The Alaknanda River flows orthogonally to the major and minor litho-tectonic discontinui... more ABSTRACT The Alaknanda River flows orthogonally to the major and minor litho-tectonic discontinuities of Himalaya. The drainage network of the river traverses through the climatic gradients ranging from 1200 mm/year at the foothills to ~3000 mm/year near the mountain front of Higher Himalaya. Thus these fluvial terraces preserve a composite record of 1) regional variations in climate, 2) local and regional tectonics. A morpho-tectonic navigation along Alaknanda valley between Rudraprayag and Karanprayag shows various levels of fluvial terraces, fossil valleys and epigenetic gorges that reflect the effect of past Tectono-climatic pulsations. In this segment the river runs parallel to the Alaknanda fault where the terrace configuration suggests that at least two major phases of rapid aggradation and bedrock incision/uplift are preserved. The terrace configuration at Gholtir show three levels of cut and fill fluvial terraces namely T1, T2 and T3 with bedrock being exposed at the base of T1. At Nagrasu two fossil valleys are observed at two different levels marking the two phases of rapid fluvial aggradation and bedrock incision and uplift. At Gaucher there are five levels of terraces, namely, T1 and T2, which are cut and fill type with bedrock at the base of T1. Further the older terraces T3-T5 are second set of cut and fill terrace sequence with bedrock at the base of T3 again suggesting two phases of valley aggradation and bedrock incision. Similarly at Bamoth two levels of cut and fill terraces are observed. The common observation at all location is northward shift of river channel probably linked with the activity of Alaknanda fault. Optically Stimulated Luminescence (OSL) chronology of the fluvial fill suggested that the aggradational phases were focused at Oxygen Isotope Stage- 3 (OIS-3) and during the transition of OIS-2 and OIS-1. The latest phase of incision in Alaknanda River took place in response to enhanced precipitation after the Last Glacial Phase between 12-10 ka. Similar conclusion from the studies elsewhere (Srivastava et al. 2008a and b; Choudhary et al., 2008) suggest that the phenomenon of Alaknanda aggradation responded to Global climatic changes where the activity along the local thrust and faults created accommodation space by laterally and vertically shifting the channel during the Late Pleistocene-Holocene.

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Research paper thumbnail of Last 20 ka of Himalayan Rivers: oscillations in-phase with global climatic changes

ABSTRACT Himalayan orogen, one of the highest continental relief, experiences a significant E-W r... more ABSTRACT Himalayan orogen, one of the highest continental relief, experiences a significant E-W rainfall gradient, houses several erosional hotspots, bears potential to change the chemical and sedimentary architecture of oceans globally. The river systems that drain through these mountains respond to continental scale epirogenic forces and to global climatic forcing. The resultant of this interaction decides upon the large-scale Morphotectonic development of the Himalaya and its foreland (Srivastava et al. 2003; Wobus et al. 2005). During the last 20 ka the rivers in Himalaya and adjoining continents have witnessed significant climatic changes ranging from widespread glaciation during the ~21-18 ka and followed by significant retreat and strengthened monsoon. This led to major shift in the hydrological regime of the rivers draining the Himalayas. An initiative, combining field investigations and chronological studies on the geomorphological and sedimentological archives of major Himalayan river valleys of (i) Spiti (Arid-Trans-Himalaya, rainfall ~100 mm/a), (ii) Mandakini, Alaknanda, Bhagirathi (NW Lesser Himalaya, rainfall ~1200 mm/a, Srivastava et al. 2008a), (iii) Marsyandi (Humid, Central Himalaya, Nepal, rainfall 2000 mm/a, Pratt et al. 2004), (iv) Teesta (Eastern Himalaya, Sikkim, Rainfall ~2500 mm/a, Mukul et al. 2007) (v) Kameng and Brahmaputra (NE Himalaya, rainfall ~3000 mm/a; Srivastava et al. 2008b; Srivastava and Misra 2008) indicated that: � The River valleys in terms of aggradation and incision oscillated in-phase with the changing climate during the last 20 ka. The climatic transition from the last glacial phase to rainfall Maxima of Holocene was characterized by large-scale valley aggradations. The Spiti River showed deviation conforming to present day rainfall conditions. The wetter conditions of the early Holocene led to increased stream power and river incision. � The rivers in NE Himalaya exhibit several phases of incision that are synchronous to aggradation in west. This is due to relatively high rainfall in the region that did not reduce below a threshold even during the drier phases of Last Glacial phase. This points towards relatively high erosional stress and associated deformation in the NE Himalaya. � The catchments in the Ganga plain responded asynchronously with their Himalayan counterparts where the significantly decreased stream power owes responsibility. � Complete evacuation and mass removal via Himalayan rivers occurs only during wetter conditions and therefore the spanning of the drier and wetter conditions should govern the degree and phases of deformation in the mountain chain like Himalaya.

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Research paper thumbnail of SPECIAL ISSUE Mountain Building and Climate-Tectonic Interaction (MBCT-2008) PREFACE

Bookmarks Related papers MentionsView impact

Research paper thumbnail of River systems in Himalaya: looking into the past through the luminescence dating technique

Himalaya, the expression of continent-continent collision and related thrust tectonics, shows hig... more Himalaya, the expression of continent-continent collision and related thrust tectonics, shows highest continental relief, experiences a significant EW rainfall gradient and variations in surface processes. In an active orogen of such a kind, mass distribution, erosion, intensity of ...

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Research paper thumbnail of Past changes in sediment dynamics in the Himalayas inferred from uranium-series isotopes

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A future big one in the North-West Himalayan syntax?

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Response of the rivers in Himalaya to Late Pleistocene-Holocene climate and neotectonic evolution of the orogeny

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Climatic control on erosion in the Himalayas over the past 40 ka

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Elemental Behaviour in the Soil Profile of the Humid Northeastern Himalaya

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Late quaternary landform evolution along the Indus River, Ladakh, NW Himalaya

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Early Holocene monsoonal fluctuations in the Garhwal higher Himalaya as inferred from multi-proxy data from the Malari paleolake

Bookmarks Related papers MentionsView impact

Research paper thumbnail of synchronicity Late Quaternary glacial advances in the Tons River Valley, Garhwal Himalaya, India and regional

Bookmarks Related papers MentionsView impact