Kavita Kumari - Academia.edu (original) (raw)

Papers by Kavita Kumari

Magnetochemistry

In this study, our aim is to investigate the structural, magnetic, and magnetocaloric properties ... more In this study, our aim is to investigate the structural, magnetic, and magnetocaloric properties of the FeNi binary alloy. The FeNi alloy with Fe65Ni35 composition was prepared by ball milling followed by the annealing and quenching processes. A Rietveld refinement analysis of structural results reveals that this system has coexisting cubic structural phases with a dominant face-centered cubic phase (Fm-3m;γ-FeNi). Magnetization results of this compound indicate the presence of ferromagnetic ordering and the magnetic transition observed around 100 K. Moreover, an Arrott plot study provides information about the order of phase transition, which is found in the second-order near the ordering temperature, whereas first-order nature is also noted in the low-temperature region. The significant magnetocaloric parameters, i.e., magnetic entropy change (ΔSM~0.495 J/kg-K) and relative cooling power (88 J/kg), are noted over a wide temperature range. The power law dependency of magnetic entro...

Frontiers in Microbiology, 2021

The ultimate role of prokaryote (bacteria and archaea), the decomposer of the wetland ecosystem, ... more The ultimate role of prokaryote (bacteria and archaea), the decomposer of the wetland ecosystem, depends on its community structure and its interaction with the environment. The present study has used three universal prokaryote primers to compare prokaryote community structure and diversity of three distinctly different wetlands. The study results revealed that α-diversity indices and phylogenetic differential abundance patterns did not differ significantly among primers, but they did differ significantly across wetlands. Microbial community composition revealed a distinct pattern for each primer in each wetland. Overall comparison of prokaryote communities in sediments of three wetlands revealed the highest prokaryote richness and diversity in Bhomra (freshwater wetland) followed by Malencho (brackish-water wetland) and East Kolkata wetland (EKW) (sewage-fed wetland). Indicator genus analysis identified 21, 4, and 29 unique indicator genera, having preferential abode for Bhomra, EK...

Advances in Fisheries Biotechnology, 2021

Molecular Biology Reports, 2021

In the present study, an integrated taxonomic approach has been applied to clarify the taxonomic ... more In the present study, an integrated taxonomic approach has been applied to clarify the taxonomic status, identity and distribution of bagrid cat sh, Mystus tengara. Comparative morphometric evaluation of M. tengara identi ed in the present study from distant geographical location revealed variations of the traits in response to body length and environment, without signi cant genetic distance. The observed morphometric traits of M. tengara were found to be overlapping with available morphometric traits of M. tengara, M. carcio and M. vittatus. Maximum likelihood phylogenetic analysis based on mitochondrial cytochrome c oxidase (COI) gene also could not resolve their identity, and ve paraphyletic clades comprising of M. tengara, M. vittatus and M. carcio from India, Nepal and Bangladeshwere observed. Morphological and genetic evidence along withcomparative evaluation of M. tengara, from its type locality, we consider M. tengara identi ed in the present study to be true, with its distribution extending from North East India to West Bengal, North India, Central India, Northern peninsular India and Bangladesh. The observation of paraphyletic subclade and evaluation of genetic distance between subclades reveals, there could be at least four cryptic species in this group. Further con rmation on the identity of M. vittatus and M. carcio, by integrated taxonomic approach based on fresh specimens collected from type locality, is required.

Journal of Electron Spectroscopy and Related Phenomena, 2021

Abstract In the present work, the effect of the oxygen partial pressure (OPP) has been studied on... more Abstract In the present work, the effect of the oxygen partial pressure (OPP) has been studied on the electronic structure of the Ce0.95Fe0.05O2-δ thin film (TF) through Raman spectroscopy, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The varying OPP, from 200 mTorr to 1 mTorr, was observed to vary the oxidation conditions during TF deposition. The oxygen valency was estimated to be reduced along with the generation of oxygen vacancies as determined via Raman analysis. The AFM analysis revealed the lowered values of the roughness parameters which indicated that reduction in OPP is associated with the smoothness of the film surface. The film surface was found to be reduced, as characterized by XPS investigation, as a result of the change in valency of Ce from +4 to +3 due to reduced OPP. The concentration of Ce3+ state was estimated to increase from 19.5% to 33% with reducing OPP. This evidently supports the formation of oxygen vacancies since the reduction of the valence state of Ce is known to be accompanied by the generation of oxygen vacancies. The O1 s spectra confirmed the oxygen non-stoichiometry as a function of OPP, whereas, Fe 2p suggested the mixed-valence state of Fe (Fe2+/Fe3+) in Ce0.95Fe0.05O2-δ (TF). To put in brief, the variation in OPP affects the chemical composition of the material by modifying its electronic structure via controlling the exchange interactions in the core structure of the compound.

Journal of Applied Ichthyology, 2017

Ten indigenous freshwater fish species belonging to nine genera and seven families were collected... more Ten indigenous freshwater fish species belonging to nine genera and seven families were collected from Gandak River, Bihar, India during December, 2014 to September, 2016. Fishes were caught using Cast nets, Gill nets, Drag nets with mesh size of 15-20 mm, 25-30 mm and 5-10 mm respectively along with Traps. Sampling was done during dry and wet seasons and a total of 682 fish were collected for analysis of their Length-Weight Relationships (LWRs). Analyses included seven species for which no previous LWRs information were available in FishBase, and new maximum lengths were recorded for three species.

Ceramics International, 2021

The electronic structure and magnetic properties of Ce 0⋅95 Fe 0⋅05 O 2 thin film (Fe-CeO 2 TF) w... more The electronic structure and magnetic properties of Ce 0⋅95 Fe 0⋅05 O 2 thin film (Fe-CeO 2 TF) were studied in the present work. The fabrication of 5% Fe-CeO 2 TF on the LaAlO 3 (LAO) (h00) substrate was performed using pulsed laser deposition (PLD) technique at 200mTorr oxygen partial pressure. Carefully deposited films were characterized through x-ray diffraction (XRD), atomic force microscopy (AFM), near edge x-ray absorption fine structure (NEXAFS) spectroscopy, and dc-magnetization measurements. XRD results indicated the polycrystalline nature of the film and showed that the film was grown along (220) preferred orientation. The AFM analysis revealed that the average surface roughness was found to increase for Fe-CeO 2 TF as compared with undoped CeO 2 TF. The NEXAFS spectral analysis revealed the formation of oxygen vacancies and reduction in valence state of Ce from +4 to +3. These outcomes evidently supported the formation of oxygen vacancies because the reduction of valence state of Ce is known to be accompanied with generation of oxygen vacancies. The dcmagnetization measurements showed room-temperature ferromagnetism in the doped films with Tc =~300 K.

SEPARATION SCIENCE PLUS, 2021

Archives of Environmental Contamination and Toxicology, 2020

Personal care product (PCP) chemicals have a greater chance of accumulation in the aquatic enviro... more Personal care product (PCP) chemicals have a greater chance of accumulation in the aquatic environments because of their volume of use. PCPs are biologically active substances that can exert an adverse effect on the ecology and food safety. Information on the status of these substances in Indian open water ecosystems is scarce. In this paper, we report the incidence of two synthetic antimicrobials, triclosan (TCS), including its metabolite methyl-triclosan (Me-TCS) and triclocarban (TCC) in Torsa, a transboundary river flowing through India. In water TCS and TCC were detected at levels exceeding their respective PNEC (Predictive No Effect Concentration). Both the compounds were found to be bioaccumulative in fish. TCS concentration (91.1-589 µg/kg) in fish was higher than that of TCC (29.1-285.5 µg/kg). The accumulation of residues of the biocides varied widely among fishes of different species, ecological niche, and feeding habits. Me-TCS could be detected in fishes and not in water. The environmental hazard quotient of both TCS and TCC in water indicated a moderate risk. However, the health risk analysis revealed that fishes of the river would not pose any direct hazard to human when consumed. This is the first report of the occurrence of these PCP chemicals in a torrential river system of the eastern Himalayan region. The rising population, industrialization, and urbanization have led to increasing demand and consumption of personal care products (PCP) used mainly in our daily life. There are many antimicrobial chemical compounds incorporated with the PCPs to increase their spectrum and efficiency (Brausch and Rand 2011; Zhang et al. 2019). Triclosan (TCS), a chlorinated diphenyl ether, and triclocarban (TCC), chlorinated diphenyl urea are two of such important synthetic antimicrobial compounds used in many personal care, hygiene, and consumer products, such as cosmetics, sanitizers, soaps, detergents, toothpaste, disinfectants, surgical scrubs, and even in textiles, shoes, etc. (Singer et al. 2002).

Tropical Ecology, 2019

This present study was conducted to extend our understanding on the relationship between Chloroph... more This present study was conducted to extend our understanding on the relationship between Chlorophyll a (Chl a) concentration and hydrological parameters typically flow velocity, environmental variables and trophic state conditions using lotic water as experimental system. River Mahanadi, India was selected as a model for the present study. Based on elevation from mean sea level, twelve sampling sites from Sambalpur to Naraj were grouped into three zones viz. upper zone (71 km), middle zone (142 km) and lower zone (103 km). Carlson Trophic State Index (CTSI) revealed eutrophic state in middle and lower zone and with mesotrophic condition in the upper zone. Along the river stretch, a negative correlation was observed between Chl a concentration and flow velocity at all three zones during post monsoon (r = − 0.15) and monsoon (r = − 0.31). Seasonal study revealed higher Chl a concentration (16.16–283.85 µg l−1) in post-monsoon with recorded mean flow velocity (0.28 ± 0.19 ms−1) as compared to monsoon season with lower Chl a (18.68–232.24 µg l−1) and mean flow velocity (0.54 ± 0.21 ms−1). Among environmental variables, water temperature and pH showed a positive correlation with Chl a. Overall, the findings of this study illustrated the occurrence of higher phytoplankton biomass (quantified as Chl a) during post-monsoon season coincides with low water velocity. The dataset of this work can be implicated for the hydrological and the ecological framework of the tropical river Mahanadi in the Indian Territory.

Journal of Electron Spectroscopy and Related Phenomena, 2019

Nanostructure of CeO2 doped with Fe ions were synthesized through co-precipitation method.  Rama... more Nanostructure of CeO2 doped with Fe ions were synthesized through co-precipitation method.  Raman Spectroscopy and NEXAFS at O K edge reveals the formation of oxygen vacancies which is further increases with Fe doping.  Fe L3,2 edge NEXAFS infers that Fe ions are in mixed valence state. The Ov at the surfaces is believed to activate the FM signals.  TheCeO2/Ce2O3 core/shell structures were used to interpret the magnetic phase at high magnetic field.  The photocatalyst activity increases as the Fe doping increase that may be related to Fe 2+ /Fe 3+ redox cycle which causes increase the degradation of MB dye.

Journal of Materials Science: Materials in Electronics, 2019

In cerium dioxide (CeO 2) as semiconductor compound, the tuning of band gap energy is a pivotal f... more In cerium dioxide (CeO 2) as semiconductor compound, the tuning of band gap energy is a pivotal feature for visible light applications. In this report, nanoparticles (NPs) of Ce 1 − x Ni x O 2 (0.0 ≤ x ≤ 0.10) were synthesized through co-precipitation route. The structural, electronic state and optical band gap were investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), near edge X-ray absorption fine structure (NEXAFS) spectroscopy, Raman scattering and UV-Vis spectroscopy. XRD results revealed the single-phase nanocrystalline behavior of CeO 2 with cubic fluorite structure. The electronic configuration of the samples, probed via NEXAFS spectra at Ce M 5, 4 edges, demonstrated that the cerium exists in Ce 4+ and Ce 3+ mixed valence states. The formation of Ce 3+ ions in the vicinity of oxygen vacancies (Ov) were assessed also via Raman scattering and XANES spectra at Ce L 3 edge. The estimated concentrations of Ce 3+ were increased from 6 to 13% as the Ni content increase from 0 to 10% respectively. Here, the inclusion of Ni 2+ ions into CeO 2 network induced additional Ov and simultaneously reduced the optical band gap from 3.9 eV for pure CeO 2 to 2.6 eV for 10% Ni doped CeO 2 NPs. Therefore, the oxygen loss population seem to be responsible for the band gap reduction. The role of Ov for creating profound donor band near the conduction band and narrowing the band gap energy were discussed.

Journal of Materials Science: Materials in Electronics, 2018

In this study, Ti 0.95 Mn 0.05 O 2−δ nanostructured thin films were fabricated by pulsed laser de... more In this study, Ti 0.95 Mn 0.05 O 2−δ nanostructured thin films were fabricated by pulsed laser deposition technique followed by rapid thermal annealing (RTA) in pure O 2 and N 2 atmospheres. The RTA process induced a substantial change in the surfaces morphology and local atomic structure around Ti 4+ cation that have been studied by means of atomic force microscopy, Raman scattering and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Raman spectra of the films were resembled to that of TiO 2 rutile phase, and the change in the width of E g (434 cm −1) Raman active modes has been attributed to oxygen non-stoichiometry. NEXAFS spectra were carried out in synchrotron facility at Ti/Mn L 3,2 edges and O-K edge. The ligand-field splitting, estimated from the energy difference between t 2g and e g features in O K-edge spectra were ~ 2.81 eV for pristine and annealed film, which is a characteristic of the TiO 2 rutile structure, and the asymmetry of t 2g and e g bands at the O-K edge has been ascribed to oxygen vacancy (Vo 2+). The annealing of film in O 2 gas optimized the surface structure and healed the Vo 2+ bridging, while the RTA in N 2 gas introduced Vo and reduced the valence state of Ti 4+ (TiO 2) into Ti 3+ (Ti 2 O 3) that have been probed by comparing the NEXAFS spectra of N 2 annealed film with the reference spectra of Ti 2 O 3. Experimental and atomic multiplet calculations revealed that the Mn ions exist in 2+ valence state.

Dalton Transactions, 2018

Eight novel luminescent and semiconducting Tl(i) β-oxodithioester complexes forming 1D/2D coordin... more Eight novel luminescent and semiconducting Tl(i) β-oxodithioester complexes forming 1D/2D coordination polymeric structures were investigated using single crystal X-ray diffraction.

Fish Physiology and Biochemistry, 2017

In the present study, full-length CYP1A cDNA from Catla catla (Catla) has been identified, and it... more In the present study, full-length CYP1A cDNA from Catla catla (Catla) has been identified, and its real-time quantitative reverse transcription PCR (qRT-PCR) expression has been evaluated in different tissues, developmental stages (0, 3, 6, 12 and 24 h and 5, 7 and 9 days post-fertilization) and copper sulphate and benzo(a)pyrene (BaP)-treated 5-day post-fertilization (dpf) larvae (6 to 6.5 mm). Various structural, comparative and phylogenetic analyses of the deduced amino acid sequence revealed that the identified gene of Catla belongs to the CYP1A1 subfamily. Among different tissues of Catla, the highest CYP1A expression was observed in the kidney followed by the liver, muscle, gill, intestine and brain. CYP1A mRNA expression was detected during all the larval developmental stages, including the unfertilized egg with the highest expression on 9 dpf. BaP (3.5 ppb) and copper sulphate (sublethal dose 0.516 ppm) challenge test for 96 h to Catla larvae revealed the highest CYP1A1 expression at 48 h post-challenge. CYP1A1 transcript also showed a concentration-dependent increase in expression following exposure at 1.75 and 3.5 ppb of BaP for 48 h. Its expression profiling indicates that it is functional at early developmental stages. It can also be used to develop a specific biomarker tool for monitoring environmental pollution.

ChemistrySelect, 2016

New ferrocenyl/pyridyl functionalized dithiocarbamate complexes, [Tl(dtc)] 1 (dtc = (N-ferrocenyl... more New ferrocenyl/pyridyl functionalized dithiocarbamate complexes, [Tl(dtc)] 1 (dtc = (N-ferrocenyl-N-2-methylpyridyl) dithiocarbamate (L1) 1, (N-ferrocenyl-N-methyl) dithiocarbamate (L2) 2, (N-methylthiophene-N-3-methylpyridyl) dithiocarbamate (L3) 3, (N-4-chlorobenzyl-N-3-methylpyridyl) dithiocarbamate (L4) 4 and (N-4-methylbenzyl-N-3-methylpyridyl) dithiocarbamate (L5) 5) have been synthesized and characterized by elemental analyses, IR, UV-Vis., 1 H and 13 C { 1 H} NMR spectroscopy. Their crystal structures revealed polymeric structures based on dimeric [Tl(dtc)] 2 scaffolds which are linked via Tl•••Tl, Tl-N(Py) and Tl•••S bonds and rare CÀH•••Tl anagostic, C-S•••Tl, Tl•••N(dtc), Tl•••C and Tl•••p(arene) intermolecular bonding interactions which have been assessed by theoretical calculations.The supramolecular structures in these complexes have been sustained by weak CÀH•••S, CÀH•••N, CÀH•••Cl, CÀH•••p, p••• p and H•••H interactions. Except for 1 and 2 having ferrocene groups as quenchers, all the complexes show luminescent characteristics in the solid phase. Complexes 1-5 are weakly conducting (s rt ,10 À4-10 À7 S cm À1 , Ea= 0.89-1.00 eV) but show semiconducting behavior in the solid state. The TGA decomposition products of 1-5 revealed formation of binary TlS and ternary Fe 2 Tl 4 S 5 and Fe 3 Tl 2 S 4 sulfide materials.

Advances in Intelligent Systems and Computing, 2016

The network density, energy consumption, and connectivity are the most important design parameter... more The network density, energy consumption, and connectivity are the most important design parameters for a self-organizing wireless sensor network. This paper presents a social impact theory-based multi-objective strategy for optimizing these parameters. The proposed strategy optimizes the clustering schemes and signal strengths along with the operational modes of the sensor nodes. The algorithm has been implemented in MATLAB using an open source social impact theory Optimization toolbox (http://mloss.org/software/view/457/). The suggested algorithm offers the achievement of optimal designs and satisfies the different design parameters.

Fungal Biology, 2016

Leaf binding symptoms accompanied with necrosis of the leaves was recorded on sugarcane cv. CoS 0... more Leaf binding symptoms accompanied with necrosis of the leaves was recorded on sugarcane cv. CoS 07250, CoS 98259, CoSe 01434 at Sugarcane Research Institute Shahjahanpur, Uttar Pradesh, India during last week of June to September, 2011–2012. Early death of infected shoots, dwarfing and fascination was also noticed in affected clumps. Incidence of disease varied from variety to variety (8–15 %). The growth of affected plants was checked. Association of a fungus, Fusarium moniliforme was identified (By Dr Atul Singh and further confirmed by ARI Pune) and confirmed based on biological, microscopic and molecular detection with ITS specific primers set (ITS 1 and ITS 4). BLAST analysis of submitted sequence (KM382420) revealed maximum identity of 97–98 % with Fusarium sp. Foliar spray of Carbendazim during the grand growth period (6–8 month old crop) at fortnightly interval (@0.1 % w/v) was found to be most effective in controlling the incidence of the disease followed by Copper oxychloride.

Journal of Evolution of Medical and Dental Sciences, 2014

Bilateral primary non-Hodgkin's lymphoma of breast is a rare entity because incidence wise it com... more Bilateral primary non-Hodgkin's lymphoma of breast is a rare entity because incidence wise it comprises less than 10% of all primary breast lymphoma. Here a case of bilateral breast lump is reported and reviewed, who had bilateral axillary node involvement and which trucut biopsy showed evidence of primary non-Hodgkin's lymphoma and responded satisfactory to chemotherapy.

Phytopathogenic Mollicutes, 2015