Browsing by Author "Ishwar Singh"

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Active tectonics in the Assam seismic gap between the meizoseismal zone of AD 1934 and 1950 earthquakes along eastern Himalayan front, India
(Springer, 2018) Arjun Pandey; Ishwar Singh; Rajeeb Lochan Mishra; Rao Singh Priyanka; Hari B Srivastava; R. Jayangondaperumal
The Assam Seismic Gap has witnessed a long seismic quiescence since the Mw∼ 8.4 great Assam earthquake of AD 1950. Owing to its improper connectivity over the last decades, this segment of the Himalaya has long remained inadequately explored by geoscientists. Recent geodetic measurements in the eastern Himalaya using GPS document a discrepancy between the geologic and geodetic convergence rates. West to east increase in convergence rate added with shorter time span earthquakes like the 1697 Sadiya, 1714 (Mw∼ 8) Bhutan and 1950 (Mw∼ 8.4) Tibet–Assam, makes this discrepancy more composite and crucial in terms of seismic hazard assessment. To understand the scenario of palaeoearthquake surface rupturing and deformation of youngest landforms between the meizoseismal areas of Mw∼ 8.1 1934 and 1950 earthquakes, the area between the Manas and Dhanshiri Rivers along the Himalayan Frontal Thrust (HFT) was traversed. The general deformation pattern reflects north-dipping thrust faults. However, back facing scarps were also observed in conjugation to the discontinuous scarps along the frontal thrust. Preliminary mapping along with the published literature suggests that, in the eastern Himalayan front the deformation is taking place largely by the thrust sheet translation without producing a prominent fault-related folds, unlike that of the central and western Himalayas. © 2018, Indian Academy of Sciences.
Establishing primary surface rupture evidence and magnitude of the 1697 CE Sadiya earthquake at the Eastern Himalayan Frontal thrust, India
(Nature Research, 2021) Arjun Pandey; R. Jayangondaperumal; György Hetényi; Rao Singh Priyanka; Ishwar Singh; Pradeep Srivastava; Hari B. Srivastava
Historical archives refer to often recurring earthquakes along the Eastern Himalaya for which geological evidence is lacking, raising the question of whether these events ruptured the surface or remained blind, and how do they contribute to the seismic budget of the region, which is home to millions of inhabitants. We report a first mega trench excavation at Himebasti village, Arunachal Pradesh, India, and analyze it with modern geological techniques. The study includes twenty-one radiocarbon dates to limit the timing of displacement after 1445 CE, suggesting that the area was devastated in the 1697 CE event, known as Sadiya Earthquake, with a dip-slip displacement of 15.3 ± 4.6 m. Intensity prediction equations and scaling laws for earthquake rupture size allow us to constraints a magnitude of Mw 7.7–8.1 and a minimum rupture length of ~ 100 km for the 1697 CE earthquake. © 2021, The Author(s).
Evidence of the 1950 Great Assam Earthquake Surface Break Along the Mishmi Thrust at Namche Barwa Himalayan Syntaxis
(Blackwell Publishing Ltd, 2021) Ishwar Singh; Arjun Pandey; Rajeeb Lochan Mishra; Rao Singh Priyanka; Atul Brice; R. Jayangondaperumal; Vaibhav Srivastava
Paleoseismological trenching at Kamlang Nagar along the Mishmi Thrust in the Eastern Himalayan Syntaxis, aided by radiocarbon analyses of charcoals yielding ages of 1111–914 B.C. to A.D. 1761–1968 infer primary evidences of co-seismic surface faulting. Correlation with results of an earlier paleoseismological study indicates two successive surface rupturing earthquakes at ∼1800-years interval, the most recent event very likely corresponding to the 1950 Assam earthquake (Mw 8.6). A dip-slip displacement of 24.6 ± 4.6 m was estimated along a 25 ± 5°E dipping fault during the 1950 earthquake. Our study suggests dual surface faulting by the 1950 event along two orthogonal fault systems, that is, the Himalayan Frontal Thrust and the Mishmi Thrust. It thus emphasizes that, the seismicity pattern in the Mishmi Range where the locked zone of the Main Himalayan Thrust extends beyond the suture zone, is unlike that of the western and central Himalaya. © 2021. American Geophysical Union. All Rights Reserved.
Glycine betaine modulates chromium (VI)-induced morpho-physiological and biochemical responses to mitigate chromium toxicity in chickpea (Cicer arietinum L.) cultivars
(Nature Research, 2022) Deepti Singh; Chandan Kumar Singh; Dharmendra Singh; Susheel Kumar Sarkar; Saroj Kumar Prasad; Nathi Lal Sharma; Ishwar Singh
Chromium (Cr) accumulation in crops reduces yield. Here, we grew two chickpea cultivars, Pusa 2085 (Cr-tolerant) and Pusa Green 112 (Cr-sensitive), in hydroponic and pot conditions under different Cr treatments: 0 and 120 µM Cr and 120 µM Cr + 100 mM glycine betaine (GB). For plants grown in the hydroponic media, we evaluated root morphological attributes and plasma membrane integrity via Evans blue uptake. We also estimated H+-ATPase activity in the roots and leaves of both cultivars. Plants in pots under conditions similar to those of the hydroponic setup were used to measure growth traits, oxidative stress, chlorophyll contents, enzymatic activities, proline levels, and nutrient elements at the seedling stage. Traits such as Cr uptake in different plant parts after 42 days and grain yield after 140 days of growth were also evaluated. In both cultivars, plant growth traits, chlorophyll contents, enzymatic activities, nutrient contents, and grain yield were significantly reduced under Cr stress, whereas oxidative stress and proline levels were increased compared to the control levels. Further, Cr uptake was remarkably decreased in the roots and leaves of Cr-tolerant than in Cr-sensitive cultivars. Application of GB led to improved root growth and morpho-physiological attributes and reduced oxidative stress along with reduced loss in plasma membrane integrity and subsequently increase in H+-ATPase activity. An increment in these parameters shows that the exogenous application of GB improves the Cr stress tolerance in chickpea plants. © 2022, The Author(s).
Joint neutrino oscillation analysis from the T2K and NOvA experiments
(Nature Research, 2025) Robert Miles Zwaska; Jaroslav Zalesak; S. Zadorozhnyy; Katsuya Yonehara; Alejandro Yankelevich; A. Yahaya; Barbara Yaeggy; Yiwen Xiao; Wanwei Wu; Shuai Wu; Jeremy A. Wolcott; Don Athula A. Wickremasinghe; D. W. Whittington; Matthew J. Wetstein; C. Weber; Thomas K. Warburton; Michael Wallbank; Abigail Victoria Waldron; K. J. Vockerodt; Z. Vallari; P. L. Vahle; Jon Urheim; J. Trokan-Tenorio; D. Tran; Yagmur Torun; M. Titus; Emrah Tiras; Jennifer A. Thomas; Tarak Thakore; P. Tas; N. Talukdar; Artur A. Sztuc; C. Sweeney; S. Swain; Andrew Sutton; Louise Suter; Matthew Strait; Karel Soustružník; Alexandre B. Sousa; Nickolas Solomey; Pavel V. Snopok; Jan Smolík; A. Smith; Dinesh Kumar Singha; Simranjit Singh Chhibra; Venktesh Singh; Prabhjot Singh; Ishwar Singh; Saurabh Shukla; W. Shorrock; Alexander K. Shmakov; Shivam; Andrey S. Sheshukov; P. Sharma; Peter Shanahan; S. Sánchez Falero; Mayly Calderón De La Barca Sánchez; O. B. Samoylov; P. K. Roy; Edgar E. Robles; Brian J. Rebel; Bryan J. Ramson; Miriama Rajaoalisoa; V. Raj; Aleena Rafique; L. R. Prais; J. C.C. Porter; Robert K. Plunkett; Roberto Petti; G. Pawloski; Ryan B. Patterson; Lipsarani Panda; Jonathan M. Paley; A. Pal; Mustafa Ozkaynak; T. Olson; Alexander G. Olshevskiy; H. Oh; A. Norrick; Andrew J. Norman; Evan Niner; Ryan J. Nichol; Jeffery K. Nelson; S. Nelleri; Donna L. Naples; D. Myers; Kevin Mulder; Mathew Muether; Leon Mualem; Wei Mu; A. D. Morozova; Adam Moren; Mohanta K. Rukmani; Sanjib Ratan Mishra; W. H. Miller; Ting Miao; Holger Meyer; M. D. Messier; Bhumika Mehta; Viktor A. Matveev
The landmark discovery that neutrinos have mass and can change type (or flavour) as they propagate—a process called neutrino oscillation1, 2, 3, 4, 5–6—has opened up a rich array of theoretical and experimental questions being actively pursued today. Neutrino oscillation remains the most powerful experimental tool for addressing many of these questions, including whether neutrinos violate charge-parity (CP) symmetry, which has possible connections to the unexplained preponderance of matter over antimatter in the Universe7, 8, 9, 10–11. Oscillation measurements also probe the mass-squared differences between the different neutrino mass states (Δm2), whether there are two light states and a heavier one (normal ordering) or vice versa (inverted ordering), and the structure of neutrino mass and flavour mixing12. Here we carry out the first joint analysis of datasets from NOvA13 and T2K14, the two currently operating long-baseline neutrino oscillation experiments (hundreds of kilometres of neutrino travel distance), taking advantage of our complementary experimental designs and setting new constraints on several neutrino sector parameters. This analysis provides new precision on the Δm322 mass difference, finding 2.43−0.03+0.04×10−3eV2 in the normal ordering and −2.48−0.04+0.03×10−3eV2 in the inverted ordering, as well as a 3σ interval on δCP of [−1.38π, 0.30π] in the normal ordering and [−0.92π, −0.04π] in the inverted ordering. The data show no strong preference for either mass ordering, but notably, if inverted ordering were assumed true within the three-flavour mixing model, then our results would provide evidence of CP symmetry violation in the lepton sector. © The Author(s) 2025.
Photocatalytic Anticancer Activity of Cyclometalated Ir(III) Complexes: A Mechanistic Insight
(John Wiley and Sons Ltd, 2025) Ashish Kumar Kumar Yadav; Virendra Pratap Singh; Ishwar Singh; Amit Kunwar; Biplob Koch; Samya Banerjee
Three novel cyclometalated Ir(III) complexes, Ir1–Ir3, were synthesized and thoroughly characterized. These complexes exhibited absorption in the 350–480 nm range, making them suitable candidates for visible-light-mediated photocatalytic cancer therapy. Under visible-light exposure in a DMSO:PBS (1:99 v/v) solvent system, all three photocatalysts demonstrated high efficiency in facilitating NADH oxidation, attaining turnover frequencies (TOFs) in the range of 499–698 h⁻1, exceeding the performance of most of the previously reported Ir(III)-based photocatalysts. Mechanistic studies verified the involvement of type I and type II pathways for ROS generation. Cytotoxicity studies highlighted significant photocytotoxic effects of Ir1–Ir3 in human lung adenocarcinoma cells (A549), with Ir3 emerging as the most potent under light exposure. Additionally, the negligible dark and light cytotoxicity of Ir3 against human embryonic kidney cells (HEK-293) demonstrated the safety profile of Ir3. Furthermore, the mechanistic studies in A549 cells revealed that Ir3 promoted mitochondrial membrane depolarization and activated caspase-3/7-dependent apoptotic pathways through light-triggered ROS generation and NADH oxidation. These findings highlight Ir3 as a potent dual-action cancer phototherapeutic, capable of synergistically inducing type-I and type-II anticancer activity, and efficient NADH photo-oxidation. This work presents a promising platform for developing multifunctional photocatalytic agents in cancer therapy. © 2025 Wiley-VCH GmbH.