Browsing by Author "Prashant Kumar"

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Assessing L. donovani Skin Parasite Load: A Proof of Concept Study of a Microbiopsy Device in an Indian Setting
(Frontiers Media S.A., 2021) Kristien Cloots; Om Prakash Singh; Abhishek Kumar Singh; Gert Van der Auwera; Prashant Kumar; Mallikarjuna Rao Gedda; Tulika Kumari Rai; Epco Hasker; Shyam Sundar; Marleen Boelaert
Background: In the endgame of the elimination initiative of visceral leishmaniasis (VL) on the Indian subcontinent, one of the main questions remaining is whether asymptomatically infected individuals also contribute to transmission. We piloted a minimally invasive microbiopsy device that could help answer this question. While the potential of this device has been previously illustrated in Ethiopia, no such information is available for the setting of the Indian subcontinent. In this proof of concept study we aimed to assess 1) to what extent skin parasite load obtained with the new microbiopsy device correlates with disease status, 2) to what extent skin parasite load correlates with blood parasite load in the same subject, and 3) to what extent the skin parasite load obtained from different sampling sites on the body correlates with one another. Methods: We performed a pilot study in Bihar, India, including 29 VL patients, 28 PKDL patients, 94 asymptomatically infected individuals, 22 endemic controls (EC), and 28 non-endemic controls (NEC). Presence of infection with L. donovani in the blood was assessed using Direct Agglutination Test, rK39 ELISA, Whole Blood Analysis measuring IFN-γ and qPCR. A skin sample was collected with the microbiopsy device on two different locations on the body. PKDL patients provided a third skin sample from the edge of a PKDL lesion. Parasite load in the skin was measured by qPCR. Findings: We found a clear correlation between the skin parasite load obtained with the microbiopsy device and disease status, with both higher skin parasite loads and higher proportions of positive skin samples in VL and PKDL patients compared to asymptomatics, EC, and NEC. No clear correlation between skin parasite load and blood parasite load was found, but a moderate correlation was present between the skin parasite load in arm and neck samples. In addition, we found four positive skin samples among asymptomatic individuals, and 85% of PKDL lesions tested positive using this microbiopsy device. Conclusions: In line with previous pilot studies, our results from an Indian setting suggest that the microbiopsy device provides a promising tool to measure skin parasite load, and – if validated by xenodiagnosis studies – could facilitate much needed larger scale studies on infectiousness of human subgroups. In addition, we advocate further evaluation of this device as a diagnostic tool for PKDL. © Copyright © 2021 Cloots, Singh, Singh, Van der Auwera, Kumar, Gedda, Rai, Hasker, Sundar and Boelaert.
Bio-catalysts and catalysts based on ruthenium(II) polypyridyl complexes imparting diphenyl-(2-pyridyl)-phosphine as a co-ligand
(2011) Prashant Kumar; Ashish Kumar Singh; Rampal Pandey; Daya Shankar Pandey
Reactions of the ruthenium complexes [Ru(κ3-tpy)(PPh 3)Cl2, [Ru(κ3-tptz)(PPh 3)Cl2 and [Ru(κ3-tpy)Cl3 [tpy = 2,2′:6′,2′′-terpyridine; tptz = 2,4,6-tris(2-pyridyl)- 1,3,5-triazine with diphenyl-(2-pyridyl)-phosphine (PPh2Py) have been investigated. The complexes [Ru(κ3-tpy)(PPh 3)Cl2 and [Ru(κ3-tptz)(PPh 3)Cl2 reacted with PPh2Py to afford [Ru(κ3-tpy)(κ1-P-PPh2Py) 2Cl+ (1) and [Ru(κ3-tptz) (κ1-P-PPh2Py)2Cl+ (2), which were isolated as their tetrafluoroborate salts. Under analogous conditions, [Ru(κ3-tpy)Cl3 gave a neutral complex [Ru(κ3-tpy)(κ1-PPh2Py)Cl 2 (3). Upon treatment with an excess of NH4PF6 in methanol, 1 and 2 gave [Ru(κ3-tpy)(κ1-P- PPh2Py)(κ2-P,N-PPh2Py)(PF 6)2 (4) and [Ru(κ3-tptz) (κ1-P-PPh2Py)(κ2-P,N-PPh 2Py)(PF6)2 (5) containing both monodentate and chelated PPh2Py. Further, 4 and 5 reacted with an excess of NaCN and CH3CN to afford [Ru(κ3-tpy)(κ1-P- PPh2Py)2(CN)(PF6) (6), [Ru(κ3- tpy)(κ1-P-PPh2Py)2(NCCH 3)(PF6)2 (7), [Ru(κ3-tptz) (κ1-P-PPh2Py)2(CN)PF6 (8) and [Ru(κ3-tptz)(κ1-P-PPh2Py) 2(NCCH3)(PF6)2 (9) supporting hemi labile nature of the coordinated PPh2Py. The complexes have been characterized by elemental analyses, spectral (IR, NMR, electronic absorption, FAB-MS), electrochemical studies and structures of 1, 2 and 3 determined by X-ray single crystal analyses. At higher concentration level (40 μM) the complexes under investigation exhibit inhibitory activity against DNA-Topo II of the filarial parasite S. cervi and 3 catalyses rearrangement of aldoximes to amide under aerobic conditions. © 2011 Elsevier B.V. All rights reserved.
Coordination polymers and monomers based on new aminocarboxylate ligands: A cadmium(II) polymer containing dimeric aqua-bridged cadmium complex governed by polymeric chain
(Elsevier S.A., 2011) Rampal Pandey; Mahendra Yadav; Prashant Kumar; Pei-Zhou Li; Sanjay Kumar Singh; Qiang Xu; Daya Shankar Pandey
The synthesis and characterization of novel coordination polymers [Co(HCCB)(H2O)2]n (1), [Zn(HCCB)(H 2O)2]n (2), {[Cd(HCCB)2]·0. 5[Cd(μ-H2O)(H2O)4]2}n (3) and [Cu(HCCB)(H2O)2]n (4) based on 3-(carboxymethylamino)-4-chlorobenzoic acid (H3CCB) and mononuclear complexes [Cu(HBCCB)(H2O)]·H2O (5), [Co(HBCCB)(H2O)]·H2O (6), [Zn(HBCCB)(H 2O)] (7) and [Cd(HBCCB)(H2O)] (8) containing 3-bis(carboxymethylamino)-4-chlorobenzoic acid (H3BCCB) have been described. The compounds under investigation have been characterized by elemental analyses, spectral studies and structures of 1-3 and 5 determined crystallographically. Structural data of 1 and 2 revealed that the deprotonated HCCB2- bridges metal centers leading to a double stranded 1D chain. On the other hand, the HCCB2- coordinated thorough carboxylate oxygen and amino nitrogen in 3 to afford a 1D chain whose charge neutrality is maintained by inclusion of aqua-bridged dimer [{Cd(μ-H2O)(H 2O)4}2]4+. Strong Cu⋯Cl interaction (2.754 ) in 5 imposes a coordination geometry that is half-way between the square planar and square pyramidal. The H3CCB, H 3BCCB and 1-3 and 5 are fluorescent at rt. Thermal studies (TG and DSC) on 1-3 suggested higher stability of 2 relative to 1 and 3 [ΔH f (kcal/mol), ΔSf = 152.17, 0.60, 1; 195.56: 0.86, 2; 69.33:0.36, 3]. © 2011 Elsevier B.V. All rights reserved.
Delineation of groundwater potential zones and its extent of contamination from the hard rock aquifers in west-Bengal, India
(Academic Press Inc., 2024) Prashant Kumar; Dev Sen Gupta; Khushwant Rao; Arkoprovo Biswas; Parthapratim Ghosh
This study evaluates the groundwater potential and quality in the parts of Chhotanagpur Gneissic Complex situated in the East Indian Shield. The region has faced groundwater development challenges for several decades. Therefore, in the study area, it is crucial to address the depletion of both groundwater quality and quantity, as this facilitates the identification of potential uncontaminated groundwater zones. The present study interprets the groundwater potential zones (GWPZ) utilizing an analytical hierarchical process (AHP) integrated with hydrogeochemical analysis. Several thematic maps were prepared to delineate the GPWZ. It has been found that ∼0.6% of the study area has a very good potential zone, 14.4% has good, 52% has moderate, and approximately 32% and 0.9% have low to very low prospective groundwater resources, respectively. The authentication of results was found to be excellent (91.4%) with the Area Under Curve (AUC). Analysis of hydrogeochemical data suggests that Mixed Ca–Na–HCO3, Mixed Ca–Mg–Cl, Ca–HCO3, and Na–Cl are the dominant water types in the study area. The principal component analysis suggests that Na+, Mg2+, Cl−, NO3−, and SO42− significantly contribute to groundwater chemistry. The K-means clustering and hierarchical cluster analysis classified groundwater samples into three clusters based on the hydrogeochemical characteristics. It is inferred that silicate weathering and reverse ion reactions through rock-water interaction control geogenic processes for groundwater chemistry. It is also inferred that regions with poor to unsuitable water quality indexes also have low GWPZ. Further, groundwater for irrigation is also accessed and found unsuitable at some locations. This research contributes to comprehending groundwater characteristics in analogous geological regions globally. Additionally, it assists in implementing preventive actions to mitigate groundwater contamination, consequently lowering health risks and formulating sustainable plans for the future. © 2024 Elsevier Inc.
Effect of environmental factors on the communal roosting behavior of House crow (Corvus splendens)
(Triveni Enterprises, 2025) Prashant Kumar; Ajit Kumar Sharma; Kavita Pal; Awadhesh Kumar Shukla
Aim: To observe the effect of environmental factors influenced by the anthropogenic activities on various events of roosting behavior of House crow (Corvus splendens) . Methodology: All Roost sites were located in the vicinity of highly urbanized settlements with ample anthropogenic light and sound. Correlation analysis was carried out to work out how environmental factors affect various roosting events. Multiple regression analysis suggested best fitted model to explain the variability observed in roosting events. Sunset time, temperature, humidity, illumination and sound intensitywere recorded. Four principal events viz., time of first arrival, time of half arrival, time of last arrival and mean time of last vocal were observed. In addition, three derived events viz. duration between sunset time to first arrival, first arrival to last arrival and last vocal were also studied. Results: It was found that sunset time, temperature, humidity, illumination and sound intensity in part were correlated and predictors for different principle and derived roosting events. Anthropogenic light and sound affected roosting events via altering intensity and duration of light and sound. An extended duration of derived events were observed on comparing our findings with previously available record. It was proposed that in addition to altered abiotic conditions, interplay of various other complex cognitive processes while roosting may be a contributor to these times lapsed. Interpretation: Environmental factors along with anthropogenic light and sound affect roosting events. Therefore, anthropogenic activities should be managed to avoid adverse consequences on roosting behavior and thus, the survival of birds. © Triveni Enterprises, Lucknow (India).
Electrical Resistivity and Induced Polarization signatures to delineate the near-surface aquifers contaminated with seawater invasion in Digha, West-Bengal, India
(Elsevier B.V., 2021) Prashant Kumar; Prarabdh Tiwari; Anand Singh; Arkoprovo Biswas; Tapas Acharya
The Digha-Shankarur-Tajpur-Mandarmani (DSTM) area in West-Bengal is well known for seawater invasion in shallow aquifers. In the present work, geophysical investigations such as Electrical Resistivity Imaging (ERI) and Induced Polarization (IP) data were used to delineate the possible zones of shallow aquifers contaminated with seawater. Smoothness-constrained least square and unstructured grid-based finite element methods were applied to interpret ERI data. The finite element method based inversion technique adopted in this study is better in terms of the final resolution of interpretation. Furthermore, the resistivity imaging survey showed low resistive zones (0–5 Ωm) in shallow aquifers. Subsequently, the IP data with low chargeability indicates probable zones of seawater invasion. These affected zones are associated mostly with clay and sandy layers up to a depth of 30 m. Moreover, the geophysical data suggests that the seawater invasion zones do not show any linear relationship throughout the area. This is mainly because the anthropogenic activities have overshadow geogenic activities. Hence, human-induced activities should be restricted in the present study area on the landward side to reduce the hazards related to seawater invasion in the groundwater aquifers in the region. © 2021 Elsevier B.V.
First examples of homo-/heteroleptic bi-/tri-nuclear complexes containing 5-ferrocenyldipyrromethene
(2009) Mahendra Yadav; Prashant Kumar; Ashish Kumar Singh; Joan Ribas; Daya Shankar Pandey
The first examples of homo- and heteroleptic complexes containing 5-ferrocenyldipyrromethene (fcdpm) [Cu(fcdpm)2] (1) [Cu(fcdpm)(acac)] (2), [Ni(fcdpm)(acac)] (3) and [Zn(fcdpm)2] (4) (acac = acetylacetonato) are described. Formation of the asymmetric metal complexes has been followed by electronic absorption and infrared spectroscopy. The complexes have been characterised by elemental analyses and spectral studies. Structures of [Cu(fcdpm)2] (1), [Cu(fcdpm)(acac)] (2) and [Ni(fcdpm)(acac)] (3) have been determined crystallographically. Structural data revealed that the metal centre in the copper complexes [Cu(fcdpm)2] (1), [Cu(fcdpm)(acac)] (2) and the nickel complex [Ni(fcdpm)(acac)] (3) adopts a distorted square planar geometry. © The Royal Society of Chemistry 2009.
Fluorescent zinc(II) complex exhibiting "onóffón" switching toward Cu2+ and Ag+ ions
(2011) Rampal Pandey; Prashant Kumar; Ashish Kumar Singh; Mohammad Shahid; Pei-Zhou Li; Sanjay Kumar Singh; Qiang Xu; Arvind Misra; Daya Shankar Pandey
Binuclear zinc(II) and copper(II) complexes based on a new Schiff base ligand N,N0-bis(2-hydroxybenzilidene)- 2,4,6-trimethylbenzene-1,3-diamine (H2L) have been synthesized. The ligand H2L and complexes under investigation have been characterized by elemental analyses, spectral (FT-IR, 1H, 13C NMR, ESI-MS, electronic absorption, emission), and electrochemical studies. The structures of H2L and complexes [{Zn(C23H18N2O2)} 2] (1) and [{Cu(C23H18N2O 2)}2] .H2O (2) have been determined crystallographically. Selective "Onóff- On" switching behavior of the fluorescent complex 1 has been studied. The fluorescence intensity of 1 quenches (turnsóff) upon addition of Cu2+, while enhances (turnsón) inthepresence of Ag+ ions. The mechanisms of "Onóffón" signaling have been supported by 1H NMR, ESI-MS, electronic absorption, and emission spectral studies. Job's plot analysis supported 1:1 and 1:2 stoichiometries for Cu2+ and Ag + ions, respectively. Association and quenching constants have been estimated by the Benesi-Hildebrand method and Stern-Volmer plot. Moreover, 1 mimics a molecular keypad lock that follows correct chemical input order to give maximum output signal. © 2011 American Chemical Society. © 2011 American Chemical Society. © 2011 American Chemical Society.
Geophysical and hydrogeological investigation for the saline water invasion in the coastal aquifers of West Bengal, India: a critical insight in the coastal saline clay–sand sediment system
(Springer, 2020) Prashant Kumar; Prarabdh Tiwari; Arkoprovo Biswas; Tapas Acharya
The Digha–Shankarpur area in West Bengal suffers from the problem of saline water intrusion in the near-surface to shallow subsurface aquifers. In the present study, geophysical surveys were conducted and integrated with measured hydrogeological parameters to delineate the possible locations of saline water–invaded zones in the shallow aquifers. One hundred eighty-eight groundwater samples were collected, and parameters like salinity, EC, total dissolved solids (TDS), pH, temperature, and water level were measured. The geophysical survey, such as resistivity profiling, self-potential, and electrical resistivity imaging techniques, was applied. High TDS, salinity, and EC were observed in various places. Resistivity profiling survey indicates a low resistivity zone (< 10 Ωm), self-potential anomaly indicates a positive anomaly and resistivity imaging survey indicated very low resistivity zones (0–3 Ωm) in near-surface to shallow subsurface locations which are concurrent with the other coastal aquifers in the eastern part of India. These low resistivity zones are interpreted as saline water intrusion zone mixed with clay/sand layers up to a depth of 15 m possibly due to the ingression of seawater and also due to anthropogenic activities. Hence, protection from seawater intrusion from the canals into the coastal aquifers (shallow and deep) and human-made activities should be restricted to minimize the effect of saline water pollution. © 2020, Springer Nature Switzerland AG.
Geophysical investigation for seawater intrusion in the high-quality coastal aquifers of India: a review
(Springer Science and Business Media Deutschland GmbH, 2023) Prashant Kumar; Prarabdh Tiwari; Arkoprovo Biswas; Tapas Acharya
Around the globe, seawater intrusion in the coastal aquifer is a significant problem. Excessive groundwater extraction because of population growth, industrialization, tourism, and other anthropogenic activities and geogenic processes initiates and accelerates this problem. The contaminated groundwater impacts the health, economic activities, and social and cultural development of coastal regions. This work aims to explore the current status and a holistic comprehending review of geophysical studies applied to delineate the seawater intrusion in the high-quality coastal aquifers in India, as well as its origin and causes, mitigation strategies, and recent advancements in geophysical techniques to access the qualitative and quantitative properties of the complex aquifer system. In the future, it is recommended to do a detailed subsurface imaging of the entire coastal belt of India to decipher the lateral and vertical variation of the lithological conditions and seawater intrusion in space and time with improved/advanced geophysical techniques, which can lead toward sustainable development. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Half-sandwich arene ruthenium complexes: Synthetic strategies and relevance in catalysis
(Royal Society of Chemistry, 2014) Prashant Kumar; Rakesh Kumar Gupta; Daya Shankar Pandey
Half-sandwich arene ruthenium complexes exhibit versatile chemistry, serve as excellent precursors and find potential applications in many organic transformations. This review mainly focuses on the chemistry of piano-stool ruthenium complexes with special emphasis on the achiral or chiral-at-ruthenium center. Also, it deals with the synthesis, nomenclature and stereochemistry of arene ruthenium complexes along with mechanistic insights into the epimerization reactions and their applications in catalytic organic transformations with some selected examples. © The Royal Society of Chemistry.
Half-sandwich ruthenium, rhodium and iridium complexes containing dipyridyl amine based ligands
(2010) Daya Shankar Pandey; Ashish Kumar Singh; Mahendra Yadav; Rampal Pandey; Prashant Kumar
Compounds derived from the reactions of dimeric arene ruthenium [{(η6-arene)Ru(μ-Cl)Cl}2] (arene = benzene and p-cymene) and structurally analogous rhodium and iridium complexes [{(η5-C5Me5)M(μ-Cl)Cl}2] (M = Rh or Ir) with 2-chloro-4,6-(di-2-pyridylamino)-1,3,5-triazine (cddt) and 2,4,6-tris(di-2-pyridylamino)-1,3,5-triazine (tdat) are reported. Compounds under investigation have been characterized by elemental analyses, NMR ( 1H and 13C), electronic absorption, emission spectral and electrochemical studies. Structures of the dinuclear compounds [{(η6-C10H14)RuCl}2(cddt)] (PF6)2, [{(η5-C5Me 5)RhCl}2(cddt)]Cl2·6H2O and trinuclear compound [{(η6-C6H6)RuCl} 3(tdat)]Cl3·4H2O have been determined crystallographically. Among cddt containing compounds the {(η6- C10H14)RuCl}- units in [{(η6-C 10H14)RuCl}2(cddt)](PF6) 2 are anti, while {(η5-C5Me 5)RhCl}- in the rhodium compound [{(η5-C 5Me5)RhCl}2(cddt)]Cl2·6H 2O are syn with respect to triazine ring. Cyclic voltammetric studies on the compounds suggested lack of communication between the metal centres. Furthermore, although tdat is luminescent at room temperature compounds under investigation containing this ligand are non-luminescent in acetonitrile. Compounds derived from the reactions of dimeric arene ruthenium [{(η6-arene)Ru(μ-Cl)Cl}2] (arene = benzene and p-cymene) and structurally analogous rhodium and iridium complexes [{(η5-C5Me5)M(μ-Cl)Cl}2] (M = Rh or Ir) with 2-chloro-4,6-(di-2-pyridylamino)-1,3,5-triazine (cddt) and 2,4,6-tris(di-2-pyridylamino)-1,3,5-triazine (tdat) are described. Compounds under study have been fully characterized by analytical, spectral and electrochemical studies and structures of [{(η6-C 10H14)RuCl}2(cddt)](PF6) 2, [{(η5-C5Me5)RhCl} 2(cddt)]Cl2·6H2O, and [{(η6-C6H6)RuCl}3(tdat)]Cl 3·4H2O have been authenticated crystallographically. © 2010 Elsevier B.V. All rights reserved.
Heteroleptic rhodium complexes containing both the dipyrrin/cyclooctadiene ligands and application of [(η4-C8H12)Rh(4-pyrdpm)] in the construction of homo-/hetero-bimetallic complexes
(Elsevier Ltd, 2010) Mahendra Yadav; Prashant Kumar; Daya Shankar Pandey
Heteroleptic rhodium(I) complexes with the general formulations [(η4-C8H12)Rh(L)] [η4-C8H12 = 1,5-cyclooctadiene; L = 5-(4-cyanophenyl)dipyrromethene, cydpm; 5-(4-nitrophenyl)dipyrromethene, ndpm; and 5-(4-benzyloxyphenyl)dipyrromethene, bdpm; 5-(4-pyridyl)dipyrromethene, 4-pyrdpm; 5-(3-pyridyl)dipyrromethene, 3-pyrdpm] have been synthesized. The complex [(η4-C8H12)Rh(4-pyrdpm)] have been used as a synthon in the construction of homo-bimetallic complex [(η4-C8H12)Rh(μ-4-pyrdpm)Rh(η5-C5Me5)Cl2] and hetero-bimetallic complexes [(η4-C8H12)Rh(μ-4-pyrdpm)Ir(η5-C5Me5)Cl2], [(η4-C8H12)Rh(μ-4-pyrdpm)Ru(η6-C10H14)Cl2] and [(η4-C8H12)Rh(μ-4-pyrdpm)Ru(η6-C6H6)Cl2]. Resulting complexes have been characterized by elemental analyses and spectral studies. Molecular structures of the representative mononuclear complexes [(η4-C8H12)Rh(ndpm)] and [(η4-C8H12)Rh(4-pyrdpm)] have been authenticated crystallographically. © 2009 Elsevier Ltd. All rights reserved.
Integrating magnetic susceptibility, hydrogeochemical, and isotopic data to assess the seawater invasion in coastal aquifers of Digha, West Bengal, India
(Springer Science and Business Media Deutschland GmbH, 2022) Prashant Kumar; Arkoprovo Biswas; Sayandeep Banerjee; Sanny Rathore; Virendra Rana; Kirpa Ram; Tapas Acharya
Seawater intrusion in coastal aquifers is a major concern due to geogenic and anthropogenic activities leading to declining groundwater quality. The present study focuses on deciphering the sea water intruded zones and its extent in the Quaternary alluvial aquifer system in the coastal belt of Digha, West Bengal, India. In this study, 36 groundwater samples were collected during pre-monsoon (2020). Subsequently, an integrated approach of hydrogeological, hydrogeochemistry, bulk magnetic susceptibility, isotopic, multivariate statistical, and geochemical modeling is adopted. Spatial distribution maps of hydrological parameters (salinity, conductivity, TDS) and major ion concentration (Na+, K+, Ca2+, Mg2+, Cl−, SO42−, F−, and Br−) suggest that the northern, south-west, and eastern parts of the study area are largely affected by saltwater intrusion and are corroborated with seawater mixing index (SMI). Based on sodium adsorption ratio (SAR), sodium percentage (Na%), and Permeability index (PI) distribution maps, the same locations are identified under critical condition for the suitability of groundwater for irrigation. The order of concentration of cations and anions in the water samples are Na+ > Ca2+ > Mg2+ > K+ and HCO3− > SO4− > Cl− > Br− > F− respectively. Piper diagram shows three principal hydrochemical water types with water composition changes from fresh (86%) to saline water mix (14%). The hydrochemical facies evolution diagram depicts 81% of water samples are in the freshening phase, and 19% are in the intrusion phase. The various bivariate plots revealed that ion exchange, reverse ion exchange, silicate weathering, seawater mixing, and anthropogenic inputs are the governing factors that control groundwater evolution. R-mode factor analysis, principal component analysis (PCA), and agglomerative hierarchical cluster (AHC) also indicate the influence on groundwater from seawater mixing and/or seawater intrusion. The superlativeness of bulk magnetic susceptibility (χ) analysis of water samples in delineating seawater intruded zones is elaborated. Saturation index (SI) shows that groundwater is saturated (> 0) with calcite, dolomite, and aragonite, plausibly due to seawater ingression. Stable isotopic analysis of δ2H (− 53.979 to − 16.9578‰) and δ18O (− 7.00183 to − 1.37 ‰) suggests precipitation recharge/paleo-water at some locations and evaporation enrichment of groundwater. It is recommended to increase groundwater recharge, reduce groundwater extraction at critically affected locations, and have regular monitoring and management to control seawater intrusion. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Magnetic susceptibility investigation of the saline water intrusion problem: The LAMP-BHU protocol
(Springer, 2021) Virendra Rana; Prashant Kumar; Sayandeep Banerjee; Arkoprovo Biswas
Abstract: A protocol is presented to perform bulk magnetic susceptibility (BMS) analysis of simulated seawater/saline water using MFK2-FA Multi-Function Kappabridge instrument at Laboratory for Analyses of Magnetic and Petrofabric (LAMP), BHU to obtain a correlation between BMS and hydrogeological data such as salinity and conductivity. This LAMP-BHU Protocol involves the preparation of simulated saline water. It has been developed after BMS measurement of 20 simulated seawater samples in different frequencies, i.e., F1 (976 Hz), F2 (3904 Hz), and F3 (15616 Hz) to prepare a standard data. This standard data is further validated with field data. Fourteen water samples are collected from the field, and hydrogeological data (salinity and conductivity) and BMS at three different frequencies were measured. Further linear regression analysis is performed on the measured data. This protocol yields efficient results with F3, followed by F1 and F2 having an R2 value of 0.84, 0.60, and 0.54, respectively, for salinity, and 0.79, 0.51, and 0.40, respectively, for conductivity. Salinity and conductivity are showing a negative trend with all the frequencies. This protocol enables to delineate saline water intruded zone or extent of saline intrusion using BMS analysis. The proposed protocol is a rapid and efficient mode of determination of the saline water intruded zones in the coastal aquifers for prioritisation of groundwater assets facilitating freshwater availability in coastal areas. Research highlights: Protocol is developed for Saline water intrusion studies using magnetic susceptibility measurements.Magnetic susceptibility, salinity and conductivity was measured for simulated and field samples.Inverse relationship observed between magnetic susceptibility w.r.t. salinity and conductivity.High frequency magnetic susceptibility provides better results for gradual increase in salinity. © 2021, Indian Academy of Sciences.
Microbial consortia in biotechnology: applications and challenges in industrial processes
(Springer Science and Business Media Deutschland GmbH, 2025) Prashant Kumar; Dheeraj Chitara; Sourodip Sengupta; Paromita Banerjee; Sachchida Nand Rai
Microbial consortia, dynamic communities of interacting microorganisms, outperform single-species cultures in industrial biotechnology by overcoming metabolic bottlenecks and degrading complex compounds. These consortia are vital in bioremediation, bioenergy, bioproduction, agriculture, and wastewater treatment. In bioremediation, they efficiently break down persistent pollutants like polycyclic aromatic hydrocarbons. For bioenergy, they convert organic waste into biofuels such as methane and ethanol through multi-step metabolic processes unachievable by single microbes. They also enable sustainable synthesis of bioplastics, antibiotics, and other high-value compounds while enhancing agricultural productivity through improved nutrient availability and biocontrol of plant pathogens. Consortia degrade complex organic contaminants in wastewater treatment, ensuring cleaner effluents and environmental protection. The industrial application faces challenges, including ensuring microbial community stability, optimising performance, and scaling processes from laboratory to industrial scale. The intricate interactions within consortia complicate control, predictability, and real-time monitoring, while intellectual property and regulatory frameworks pose additional barriers. Limitations include gaps in understanding long-term ecological impacts and scalability in diverse environments. Advancements in microbial ecology, systems biology, and bioprocess engineering are crucial to address these issues. Prospects involve using CRISPR and AI to design robust consortia, improve predictive modelling, and foster interdisciplinary collaborations for sustainable applications. Overcoming these challenges will unlock the full potential of microbial consortia, revolutionise industrial processes, and advance sustainable biotechnology. © King Abdulaziz City for Science and Technology 2025.
Novel structures based on 1-(4-cyanophenyl)-imidazole resulting from weak bonding interactions
(2009) Ashish Kumar Singh; Mahendra Yadav; Prashant Kumar; Sanjay Kumar Singh; Sailaja Sunkari; Daya Shankar Pandey
Mono-nuclear complexes [M(CPI)6](X)2 (M = Co, X = NO3- 1; M = Ni, X = NO3- 2; M = Cu, X = ClO4- 3) and [Cu(CPI)4(H2O)2](NO3)2 4, based on novel bridging ligand 1-(4-cyanophenyl)-imidazole (CPI) are reported. The complexes have been characterized by elemental analyses, spectral studies and their molecular structures have been authenticated by single crystal X-ray diffraction analyses. In molecular species 1-3 metal centers are coordinated octahedrally by six CPI ligands wherein cyanophenyl rings of six ligands about the complex cations are involved in face-to-face π-π interaction with six co-planar molecules to afford unprecedented 2D sheet. Along 'c'-axis it gives a beautiful rim like motif. In complex 4, coordination about metal center Cu is distorted octahedral with four CPI ligands in the equatorial position and two water molecules occupying axial positions. In this complex hydrogen bonding interactions between the coordinated water molecules and nitrate anions results in a 1D straight chain along 'a'-axis and 2D sheets having hexagonal cavity filled by nitrate ions. The complexes upon excitation at 275-285 nm exhibit luminescences with emission maxima centered at 438-445 nm attributable to the ligand CPI at room temperature. © 2009 Elsevier B.V. All rights reserved.
Peculiar Endosymbiosis in the Cyanobiont Nostoc azollae 0708: An In Silico Approach
(Springer Nature, 2024) Minu Kesheri; Swarna Kanchan; Amit Kumar; Upasna Srivastava; Shivani Sharda; Bhagwan Malik; Tarun Mishra; Poonam Kaithal; Jitendra Narayan; Prashant Kumar; Prerna Priya; Rajeshwar P. Sinha
Nostoc azollae 0708 exhibits peculiar endosymbiosis owing to the unique commitment of cyanobiont’s association with fern throughout its life cycle. This chapter elaborates various in silico approaches adopted for intriguing proteomics aspects of Fe and Mn superoxide dismutase in the cyanobiont Nostoc azollae 0708. Prediction of physicochemical parameters elucidating molecular weight, isoelectric point (pI), instability index, aliphatic index, total no. of negatively charged residues (Asp + Glu), total no. of positively charged residues (Arg + Lys), extinction coefficient, and GRAVY are discussed in detail. Generating good quality 3D structural models for Fe-SOD and Mn-SOD by homology modeling and validation by Prosa-web, verify-3D, and PROCHECK is elaborately explained. Conservation of metal binding positions, domains, and motifs suggesting functional conservation, highly conserved exposed as well as buried amino acid residues advocating their structural and functional importance is also discussed. Generation of protein–protein interaction network using STRING illustrating the physical and functional interaction of superoxide dismutase with other proteins and biological cascade of these proteins in Nostoc azollae has been described. The NJ phylogenetic tree for Fe-SOD depicts Nostoc sp. PCC 7524 as the nearest evolutionary homolog, whereas Nostoc sp. PCC 7107 and Nostoc piscinale CENA 21 as evolutionary close homologs of Mn-SOD in Nostoc azollae. The present in silico methodologies discussed in this chapter may pave the way for further experimental validation aiding in exploring the biochemical, biotechnological, and biofertilizer potential of the cyanobiont recruited by the fern Azolla. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
Solution-Processed, Highly-Efficient Organic Field-Effect Transistor Based Hydrogen Sulfide Gas Sensor at Sub-ppm Regime
(Institute of Electrical and Electronics Engineers Inc., 2023) Varun Kumar Singh; Ankit Verma; Prashant Kumar; V.N. Mishra
In the current article, we have investigated a highly selective, sensitive, low-power, and cost-efficient hydrogen sulfide (H2S) gas sensor utilizing the thin film of conjugated organic polymer poly[2,6-(4,4-bis-(2-ethylhexyl)- 4H-cyclopenta [2,1-b; 3,4-b'] dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) as an active sensing layer. The organic thin film of PCPDTBT polymer is developed using a cost-effective, facile solution-processed floating film transfer method (FTM). In addition, the state-of-the-art technique used for annealing named 'solvent vapor annealing' offers enhanced crystallinity and excellent charge transfer along the polymer chain which significantly improves sensitivity. The fabricated organic field effect transistor (OFET) with top contact bottom gate (TCBG) configuration is thoroughly explored to investigate the thin film's electrical and gas sensing performance for toxic and hazardous H2S gas. The fabricated device worked at room temperature (RT-25 °C) and was highly sensitive to the presence of H2S gas at concentrations even lower than 1 ppm. The fabricated OFET device has excellent air stability, good response-recovery behavior (response/recovery time of 8/250 s, respectively), exceptional gas response reproducibility, and a high sensor response of 71.3% at 1 ppm H2S gas exposure. © 2001-2012 IEEE.
Spatio-temporal assessment of soil salinization utilizing remote sensing derivatives, and prediction modeling: Implications for sustainable development
(Elsevier B.V., 2024) Prashant Kumar; Prasoon Tiwari; Arkoprovo Biswas; Prashant Kumar Srivastava
This study aims to investigate the combined use of multi-sensor datasets (Landsat 4–5 & 8 OLI satellite imagery, spatial resolution = 30 m) coupled with field studies to evaluate spatio-temporal dynamics of soil salinization along the coastal belt in West Bengal, India. This study assesses soil salinization by mapping the salinity and electrical conductivity of saturation extract (ECe) and utilizing spectral signatures for estimating soil salinity. The SI change (%) was analyzed (2021–1995), categorizing increases in salinity levels into 5%, 10%, and 50% changes possibly due to salt encrustation on the soil layers. The land use land cover (LULC) change map (2021–1995) demonstrates that the study area is continuously evolving in terms of urbanization. Moreover, in the study area, soil salinity ranges from 0.03 ppt to 3.87 ppt, and ECe varies from 0.35 dSm−1 to 52.85 dSm−1. Additionally, vulnerable saline soil locations were further identified. Classification of soil salinity based on ECe reveals that 26% of samples fall into the non-saline category, while the rest belong to the saline category. The Spectral signatures of the soil samples (n = 19) acquired from FieldSpec hand spectrometer show significant absorption features around 1400, 1900, and 2250 nm and indicate salt minerals. The results of reflectance spectroscopy were cross-validated using X-ray fluorescence and scanning electron microscopy. This study also employed partial least square regression (PLSR) approach to predict ECe (r2 = 0.79, RMSE = 3.29) and salinity parameters (r2 = 0.75, RMSE = 0.51), suggesting PLSR applicability in monitoring salt-affected soils globally. This study's conclusion emphasizes that remote sensing data and multivariate analysis can be crucial tools for mapping spatial variations and predicting soil salinity. It has also been concluded that saline groundwater used for irrigation and aqua-cultural activities exacerbates soil salinization. The study will help policymakers/farmers identify the salt degradation problem more effectively and adopt immediate mitigation measures. © 2024 China University of Geosciences (Beijing) and Peking University