Browsing by Author "Ashish Kumar Singh"

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A dihydrazone based “turn–on” fluorescent probe for selective determination of Al3+ ions in aqueous ethanol
(Elsevier B.V., 2017) Divya Pratap Singh; Romi Dwivedi; Ashish Kumar Singh; Biplob Koch; Priya Singh; Vinod Prasad Singh
An efficient and highly selective dihydrazone based fluorescent probe N′,N′–bis((2–hydroxynaphthalen–1–yl)methylene)malonohydrazide (H2nmh), has been synthesized for selective detection of Al3+ ions and characterized by different physico–chemical and spectroscopic techniques. The probe shows an enhanced fluorescence in the presence of Al3+ ions in ethanol–water (2:3 v/v) solution which is not observed in the presence of other cations (Na+, K+, Mg2+, Ca2+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Pb2+, Cd2+ and Hg2+). The binding modes of H2nmh with Al3+ were studied by UV–vis, fluorescence and 1H NMR titrations. The probe act as dibasic hexa–dentate ligand and interacts with two Al3+ ions with a binding constant KB = 5.74 × 109 M−1 and detection limit 5.78 × 10−8 M. Detailed insights of probe–metal interaction mechanism were studied by mean of density functional theory (DFT) as well as time dependent–DFT calculation. MTT assay on live MCF–7 cells has been performed to evaluate the cytotoxicity of the probe which suggests viability of the probe to MCF–7 cells even at higher concentration (100 μM) with no serious cytotoxicity in cells. Live cell imaging study clearly indicates that the accumulation of Al3+ in the cytoplasm of cells can be detected by H2nmh. © 2016 Elsevier B.V.
A pyrene-thiophene based probe for aggregation induced emission enhancement (AIEE) and naked-eye detection of fluoride ions
(Elsevier B.V., 2019) Pranjalee Yadav; Sarita Gond; Ashish Kumar Singh; Vinod P. Singh
A pyrene based probe (E)-N’-(pyren-1-ylmethylene)thiophene-2-carbohydrazide (PTH), was synthesized and characterized by IR, NMR and HRMS spectroscopic tools. The probe exhibited aggregation induced emission enhancement (AIEE) in binary solvent mixture (ACN/water) on increasing water fraction and displayed bright yellow emission in solid state. Fluorescence spectroscopy, time resolved fluorescence and DLS analysis have been exploited to gain insight into the mechanism. These results indicated an enhancement in quantum yield and average lifetime with an increase in water content. In addition to intriguing AIEE property, PTH demonstrated excellent selectivity and sensitivity for F− over various other anions. A plausible mechanism for interaction of the probe with F− has been proposed on the basis of 1H NMR titration, absorption spectra and DFT study. The recognition process was found to be driven by the high electronegativity of F− leading hydrogen bonded adduct followed by deprotonation of PTH. Instant naked eye response along with commendable detection limit (2.02 × 10−7 M) and binding constant (6.18 × 104 M−1) increased the pertinency of the probe. © 2019 Elsevier B.V.
A unified 2-D model for nanowire junctionless accumulation and inversion mode MOSFET in quasi-ballistic regime
(Elsevier Ltd, 2022) Kamalaksha Baral; Prince Kumar Singh; Sanjay Kumar; Ashish Kumar Singh; Deepak Kumar Jarwal; Satyabrata Jit
A unified 2-D continuous potential model for cylindrical nanowire junctionless accumulation mode (JAM) MOSFET and conventional inversion mode (IM) MOSFET has been presented in this manuscript. The 2-D Poisson's equation in cylindrical coordinates is solved analytically with the help of the superposition principle and evanescent mode analysis of the Fourier-Bessel series is performed. Both free and depletion charges are considered in the 2-D Poisson's equation. The model thus derived is continuous across different operation regimes (depletion and accumulation/inversion) with respect to VGS. Further, a threshold voltage model is also derived from the potential model and an expression of drain-induced barrier lowering (DIBL) is formulated. The short channel drain current model is derived from the potential-based charge model and quasi-ballistic transport velocity model. Furthermore, models for transconductance (gm) and output conductance (gd) is also formulated from the drain current model. A 3-D TCAD tool from CogendaTM has been used to numerically verify our proposed unified analytical model. © 2022 Elsevier Ltd
Adsorption behaviour of o-hydroxy acetophenone benzoyl hydrazone on mild steel/hydrochloric acid interface
(Korean Society of Industrial Engineering Chemistry, 2015) Ashish Kumar Singh; Pooja Singh
The effect of synthesised o-hydroxy acetophenone benzoyl hydrazone (HABH) on the corrosion of mild steel in 1. M HCl was investigated using potentiodynamic polarisation (PDP), electrochemical impedance spectroscopy (EIS), thermogravimetric analysis, contact angle measurement and weight loss methods. The inhibition efficiency of HABH increases with surface roughness of emery paper up to 800 grits and thereafter it decreases with additional increase in surface roughness. TGA results also indicated that the inhibitor film on the surface had a relatively good thermal stability. The adsorption behaviour of HABH is experimentally investigated by contact angle measurement of acid solution on metal surface. © 2014 The Korean Society of Industrial and Engineering Chemistry.
Antimicrobials and Antibiotic Resistance Genes in Water Bodies: Pollution, Risk, and Control
(Frontiers Media S.A., 2022) Ashish Kumar Singh; Rajinder Kaur; Shashikala Verma; Samer Singh
The manuscript endeavors to provide a perspective on the role of water bodies in the spread of antimicrobial (antibiotic) resistance (AMR), antimicrobial resistant bacteria (ARB), and antimicrobial resistance genes (ARGs) among pathogens, animals, and humans. We briefly indicate how the AMR problem is globally affecting public health, along with strategies and mechanisms to combat the dissemination of ARB and ARGs. A brief systematic survey of the literature (2015-onwards) for the presence of antimicrobial residues and the occurrence of ARGs and antimicrobial resistant microorganisms in different water bodies/sources indicates the gravity of the situation and suggests their important role in the occurrence and spread of AMR, ARB, and ARGs. The prevalent water treatment methods which tend to reduce ARB and ARGs from water resources are unable to remove them completely, allowing the problem of AMR to continue and spread to organisms of concern. In this opinion article, we attempt to underline the key role of controlling the release/discharge of antimicrobial contaminants in water bodies and their buildup in checking the development and spread of AMR. The reduction in the release of antibiotic residues in the environment, especially water bodies, combined with the development of improved surveillance means and efficacious treatment/removal/decomposition methods could help curb the menace of AMR effectively. We suggest the expansion of the ambit of ‘One Health Approach to AMR crises proposed by the World Bank, 2021 to include the ‘reduction of antimicrobial contamination of the environment’ as the ‘seventh domain’ of activity to effectively achieve its objective. Copyright © 2022 Singh, Kaur, Verma and Singh.
Arbuscular Mycorrhizal Fungi: Abundance, Interaction with Plants and Potential Biological Applications
(Springer, 2020) Manoj Parihar; Manoj Chitara; Priyanaka Khati; Asha Kumari; Pankaj Kumar Mishra; Amitava Rakshit; Kiran Rana; Vijay Singh Meena; Ashish Kumar Singh; Mahipal Choudhary; Jaideep Kumar Bisht; Hanuman Ram; Arunava Pattanayak; Gopal Tiwari; Surendra Singh Jatav
Beneficial microbes associated with plant roots play an important role to achieve higher agriculture production for burgeoning population in sustainable way. Among various microbes, arbuscular mycorrhizal (AM) fungi interaction with higher land plants is unique as they occupy position both inside and outside of roots. AM fungi as a natural symbionts of land plants provide various ecological services, in particular by improving plant water and nutrition availability, soil health and fertility, alleviating stress condition and wasteland management. Mycorrhizae as a broader group of fungi include seven types of members, i.e. arbuscular, ecto, ectendo, arbutoid, monotropoid, ericoid and orchidaceous, while arbuscular and ectomycorrhizae are the most abundant and ubiquitous. In this chapter, we focus on AM fungi and provide an overview on mycorrhizal interaction, benefits, processes, production development and potential application domain under various conditions. Along with recent advances in AM fungi role under various stress condition, reclamation of problematic wastelands and production aspects, we also discuss about the basic features of AM fungi with past developments to provide an overall glimpse of this plant-fungal interaction. In spite of its growing trends, AM fungi’s current application and market sharing are far below to full potential. Regarding this, current challenges, constraints and strategies for future road map to overcome these problems are also discussed briefly. © Springer Nature Singapore Pte Ltd. 2020.
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.
Bugs for benefits: Harnessing the nutritional and environmental potential of edible insects for human consumption
(Nova Science Publishers Inc., 2025) Ramkumar; Sunaullah Bhat; Vinay Kumar; Manisha Chaudhary; Krishna Kant Prajapati; Varun Arya; Ram Kewal; Ashish Kumar Singh
The importance of finding hygienic food became a topic of discussion after COVID-19 was classified as a worldwide pandemic by the WHO. Human beings have consumed insects as a source of food, especially protein, since ancient times, and now they're getting more attention as a possible food source. An edible insect could become an environmentally friendly, sustainable source of protein in the future. Chitosan, a polysaccharide derivative of insect chitin and silk fibroin (produced by Bombyx mori), a high-quality protein, is used in various industries, viz., agriculture and biomedicine. The natural lustrous properties of silk fibres have made it a highly valuable product in the textile industry. Honeybee workers are considered master chemists, and their products have been utilised by humans for various purposes. Honey is the best natural sweetener as well as an excellent source of energy for humans, while beeswax is used for its moisture-proof properties. Pollen and bee venom also have therapeutic properties that can be used to treat various inflammatory conditions. Lac, a natural resin produced by a type of insect, is another material that has a wide range of applications in pharmaceuticals, cosmetics, and many industrial uses for surface coatings. Lac culture, the process of cultivating these insects, is a sustainable and environmentally friendly way of obtaining this valuable material. Overall, using insect by-products and insects themselves has the potential to provide sustainable solutions to global food shortages and various industries. © 2025 Nova Science Publishers, Inc.
Classification of clinical isolates of klebsiella pneumoniae based on their in vitro biofilm forming capabilities and elucidation of the biofilm matrix chemistry with special reference to the protein content
(Frontiers Media S.A., 2019) Ashish Kumar Singh; Shivangi Yadav; Brijesh Singh Chauhan; Nabarun Nandy; Rajan Singh; Kaushik Neogi; Jagat Kumar Roy; Saripella Srikrishna; Rakesh Kumar Singh; Pradyot Prakash
Klebsiella pneumoniae is a human pathogen, capable of forming biofilms on abiotic and biotic surfaces. The limitations of the therapeutic options against Klebsiella pneumoniae is actually due to its innate capabilities to form biofilm and harboring determinants of multidrug resistance. We utilized a newer approach for classification of biofilm producing Klebsiella pneumoniae isolates and subsequently we evaluated the chemistry of its slime, more accurately its biofilm. We extracted and determined the amount of polysaccharides and proteins from representative bacterial biofilms. The spatial distribution of sugars and proteins were then investigated in the biofilm matrix using confocal laser scanning microscopy (CLSM). Thereafter, the extracted matrix components were subjected to sophisticated analysis incorporating Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, one-dimensional gel-based electrophoresis (SDS-PAGE), high performance liquid chromatography (HPLC), and MALDI MS/MS analysis. Besides, the quantification of its total proteins, total sugars, uronates, total acetyl content was also done. Results suggest sugars are not the only/major constituent of its biofilms. The proteins were harvested and subjected to SDS-PAGE which revealed various common and unique protein bands. The common band was excised and analyzed by HPLC. MALDI MS/MS results of this common protein band indicated the presence of different proteins within the biofilm. The 55 different proteins were identified including both cytosolic and membrane proteins. About 22 proteins were related to protein synthesis and processing while 15 proteins were identified related to virulence. Similarly, proteins related to energy and metabolism were 8 and those related to capsule and cell wall synthesis were 4. These results will improve our understanding of Klebsiella biofilm composition and will further help us design better strategies for controlling its biofilm such as techniques focused on weakening/targeting certain portions of the slime which is the most common building block of the biofilm matrix. Copyright © 2019 Singh, Yadav, Chauhan, Nandy, Singh, Neogi, Roy, Srikrishna, Singh and Prakash. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Clerodane and ent-halimane diterpenes from polyalthia longifolia
(1995) Noriyuki Hara; Hitomi Asaki; Yoshinori Fujimoto; Yogesh Kumar Gupta; Ashish Kumar Singh; Mahendra Sahai
A hexane extract of the stem bark of Polyalthia longifolia furnished nine new clerodane and ent-halimane diterpenes, i.e. 16-hydroxycleroda-4(18),13-dien-16,15-olide, 16-oxocleroda-4(18),13E-dien-15-oic acid, cleroda-4(18),-13-dien-16,15-olide, 16-hydroxy-ent-halima-5(10),13-dien-16,15-olide, 16-oxo-ent-halima-5(10),13E-dien-15-oic acid, ent-halima-1(10),13E-dien-16,15-olide, 16-oxo-ent-halima-5(10),13E-dien-15-oic acid, ent-halima-5(10),13-dien-16,15-olide and ent-halima-5(10),13E-dien-16,15-olide, along with five known clerodane diterpenes. The structures of these compounds were elucidated by spectroscopic methods. The 13E configuration of two of the new ent-halimanes and one of the known clerodanes was firmly established by NOE experiments. © 1995.
Click inspired synthesis of hexa and octadecavalent peripheral galactosylated glycodendrimers and their possible therapeutic applications
(Royal Society of Chemistry, 2019) Anand K. Agrahari; Anoop S. Singh; Ashish Kumar Singh; Nidhi Mishra; Mala Singh; Pradyot Prakash; Vinod K. Tiwari
A Cu(i)-catalyzed azide-alkyne 1,3-dipolar cycloaddition reaction (CuAAC) has been utilized for the synthesis of novel glycodendrimers containing a rigid hexapropargyloxy benzene centered core with 6- and 18-peripheral β-d-galactopyranosidic units. Structures of the novel glycodendrimers and intermediates were well elucidated using nuclear magnetic resonance and infrared spectroscopies, matrix assisted laser desorption/ionization mass spectrometry, and size-exclusion chromatography. The therapeutic evaluations of the developed glycodendrimers were investigated and they were found to have good potential as anti-bacterial, anti-biofilm, and anti-tumour agents. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2019.
Correction: Quantum curcumin mediated inhibition of gingipains and mixed-biofilm of Porphyromonas gingivalis causing chronic periodontitis(RSC Advances (2018) 8 (40426–40445) DOI: 10.1039/C8RA08435A)
(Royal Society of Chemistry, 2019) Ashish Kumar Singh; Shivangi Yadav; Kavyanjali Sharma; Zeba Firdaus; Prerana Aditi; Kaushik Neogi; Monika Bansal; Munesh Kumar Gupta; Asheesh Shanker; Rakesh Kumar Singh; Pradyot Prakash
The authors regret the incorrect naming of the bacterial species Actinomycetemcomitans viscosus in the published article. It should be correctly shown as Actinomyces viscosus throughout, on pages 40427 (fifth line of last paragraph), 40436 (sixth line of “Individual isolates & mixed” section), 40437 (Table 2) and 40440 (Table 3). Also, the ATCC number of A. viscosus was incorrectly given as 29522 throughout the published article and should be correctly shown as 15987 in the following places: p. 40429 (“Bacterial strains and culture conditions” section and “Minimum inhibitory concentration determination” section), p. 40430 (“Determination of antibiofilm activity using tissue culture plate assay (TCP)” section), p. 40434 (“Antimicrobial assay of quantum curcumin against clinical isolates of Porphyromonas gingivalis and select reference strains” section and “Determination of minimum inhibitory concentration” section), p. 40435 (“Growth rate analysis” section), p. 40437 (Table 2), and on p. 40438 (caption to Fig. 7 (twice), caption to Fig. 8, and sixth line of “Discussion” section). An error was also present in the published article in the co-author name spelling for K. Sharma. The correct spelling of the author names is as shown here. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers. © The Royal Society of Chemistry.
Cryptococcus neoformans var. grubii: The In Vitro Antifungal Susceptibility Pattern in Addition to the Quantification of Phospholipase and Proteinase Enzymatic Activities
(Hamadan University of Medical Sciences, 2023) Munesh K. Gupta; Ragini Tilak; Namrata Pal; Ashish Kumar Singh; Jaya Chakravarty; Bhupendra Kumar
Background: Cryptococcal meningoencephalitis is a life-threatening fungal infection in human immunodeficiency virus (HIV)-infected patients. Cryptococcus neoformans var. grubii and neoformans are the causative agents that usually respond well to fluconazole and amphotericin B. However, resistance/ non-responding cryptococcal meningitis cases to fluconazole and amphotericin B have been reported globally. Methods: The causative Cryptococcus was identified by phenotypic and singleplex polymerase chain reaction (PCR) targeting the putative sugar transporter (STR1) gene. In addition, the phospholipase and proteinase enzymatic activities of the isolates were determined by the plate method using egg yolk agar and bovine serum albumin agar plates, respectively. Finally, the in-vitro minimal inhibitory concentration (MIC) of fluconazole, voriconazole, and amphotericin B against isolated C. neoformans strains was determined by the broth microdilution method. Results: A total of 50 C. neoformans strains were isolated from the cerebrospinal fluid of HIV-infected patients, which were further identified as variety grubii by simplex polymerase chain reaction (PCR). All the isolated strains producing phospholipase and proteinase enzymes were determined by the calculation of Pz, a ratio of colony diameter and diameter of colony plus the precipitation zone. A comparative high proteinase enzyme activity was observed, and these strains produced medium to high phospholipase (mean Pz 0.3720 ± 0.082, range 0.23-0.56) and proteinase activity (Mean Pz 0.3069 ± 0.086, range 0.012-0.54). A varied antifungal MIC was detected, and voriconazole had the lowest MIC50 and MIC90 (0.03 & 0.06 µg/mL) in comparison to fluconazole and amphotericin B. Conclusion: Cryptococcus neoformans var. grubii is the commonest cause of cryptococcal meningoencephalitis in HIV-infected patients. The isolates had varied extracellular hydrolytic enzyme activities. The emergence of C. neoformans strains with higher fluconazole MIC (≥ 4 mcg/mL) could have resulted in treatment failure. © 2023 The Author(s);.
Design and Simulation of Triple Material Gate InAs/Si Heterojunction TFET on SEL-BOX Substrates: Temperature Impact Analysis
(Institute of Electrical and Electronics Engineers Inc., 2021) Ashish Kumar Singh; Manas Ranjan Tripathy; Rishibrind Kumar Upadhyay; Satyabrata Jit
In this study, we have reported TCAD assessment-based analyses of DC, RF/analog, and linearity/intermodulation distortions of a triple-material-gate (TMG) electrode-based InAs/Si hetero-junction (HJ) TFET on SEL-BOX substrate (STFET). The gate electrode consists of three different metals of work function value 4.2 eV, 4.5 eV, and 4.0 eV in a cascaded manner. The gate dielectric consists of HfO2/SiO2 in a vertically stacked form in the proposed TMG-HJ-STFET structure. The electrical parameters of the proposed STFET structure have been shown to be better than those of the double-material-gate (DMG) and single-material-gate (SMG) based HJ-STFET structures. Numbers of electrical performance parameters such as the electric field, ION, IOFF, ION/IOFF ratio, subthreshold swing (SS), transconductance (gm), parasitic capacitances, and transit frequency (fT) have been investigated for all three HJ-STFETs structures under study. Linearity/intermodulation distortion investigation has been done by analysing of some important linearity parameters such as gm2, VIP2, gm3, VIP3, IIP3, IMD3 and 1-dB compression point. In Addition, we have successfully checked the temperature variation impact on some electrical parameters of the proposed structure, TGM-HJ-STFET. © 2021 IEEE.
Detection of a Neurotoxin Quinolinic Acid at Ultra-Trace Amount: SERS and DFT Study
(John Wiley and Sons Ltd, 2025) Monalisha Nayak; Chandan Bhai Patel; Om Prakash; Ashish Kumar Singh; Ranjan Kumar Singh
The presence of quinolinic acid (QA) below 100 nM is a normal condition while its increased amount may cause variety of neurodegenerative diseases. The precise detection of QA in trace amounts (nanomolar) is crucial to control its toxic effects. In the present study, the SERS-based detection of QA and its interaction at varying concentrations in human serum is carried out using silver nanoparticle substrates. The analysis of conformational dynamics of QA across different concentrations ranging from 10−3 to 10−9 M has been done. The adsorption mechanism between QA and silver nanoparticles has been studied using DFT, and the detection of QA up to nanomolar concentration is achieved. A significant shift in the SERS spectra of QA is observed between 10−4 and 10−5 M concentration, attributed to changes in adsorption geometry with varying pH and conformational change from zwitterionic QA → neutral QA. These findings are supported by UV–visible spectra, pH measurements, and DFT calculations. © 2025 John Wiley & Sons Ltd.
Dielectric modulated TFET on SELBOX substrate as a label-free biosensor applications: analytical modeling study and sensitivity analysis
(Institute of Physics, 2024) Ashish Kumar Singh; Ramesh Kumar; Satyabrata Jit
The manuscript proposes a ferroelectric heterojunction TFET (BG-FE-HJ-STFET) on SELBOX substrates with a back gate to create an ultra-sensitive label-free biosensor with dielectric modulation for the detection of neutral and charged biomolecules. Within the proposed device, four cavities have been carved out for the biomolecules’ immobilization under the front and rear gate dielectrics. By using a ferroelectric (FE) material as a gate stack, the low gate voltage is increased to be more effective by causing a negative capacitance phenomenon. The response of the proposed biosensor to four impartial biomolecules with different dielectric constants: protein (k = 8), biotin (k = 2.63), 3-Aminopropyl-triethoxysilane (APTES) (k = 3.57), and streptavidin (k = 0.1) has been investigated. Deoxyribonucleic acid (DNA), a charged biomolecule, is also examined for the dielectric constant of k = 6 concerning both charge (negative and positive) densities. The device is simulated with the commercially available SILVACO ATLASTM TCAD tool. The performance analysis relies on several figures of merit (FOMs) such as DC/RF and sensitivity (including drain current, I ON /I OFF ratio, and subthreshold swing) for both neutral and charged biomolecules. The optimized cavity structure demonstrates a notable sensitivity in drain current (2.7 × 108) and a significant I ON /I OFF sensitivity (1.42 × 1011). One of the main problems with current biosensors is the difficulty and expense of production in the nanoscale realm. © 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Distribution of Antibiotic-Resistant Enterobacteriaceae Pathogens in Potable Spring Water of Eastern Indian Himalayas: Emphasis on Virulence Gene and Antibiotic Resistance Genes in Escherichia coli
(Frontiers Media S.A., 2020) Ashish Kumar Singh; Saurav Das; Santosh Kumar; Varsha Rani Gajamer; Ishfaq Nabi Najar; Yangchen D. Lepcha; Hare Krishna Tiwari; Samer Singh
Every year millions of people die due to fatal waterborne diseases around the world especially in developing countries like India. Sikkim, a northeastern state of India, greatly depends on natural water sources. About 80% of the population of Sikkim depends on natural spring water for domestic as well as agricultural use. Recent waterborne disease outbreaks in the state raises a concerning question on water quality. In this study, we analyzed water quality especially for the detection of Enterobacteriaceae members from four districts of the state. Isolation with selective culture media techniques and taxonomic characterization of Enterobacteriaceae bacteria with 16S rRNA gene showed the prevalence of Escherichia coli (37.50%), Escherichia fergusonii (29.41%), Klebsiella oxytoca (36.93%), Citrobacter freundii (37.92%), Citrobacter amalonaticus (43.82%), Enterobacter sp. (43.82%), Morganella morganii (43.82%), Hafnia alvei (32.42%), Hafnia paralvei (38.74%), and Shigella flexneri (30.47%) in the spring water of Sikkim. Antibiotic susceptibility test (AST) showed resistance of the isolates to common antibiotics like ampicillin, amoxicillin as well as to third generation antibiotics like ceftazidime and carbapenem. None of the isolates showed resistance to chloramphenicol. E. coli isolated from spring water of Sikkim showed presence of different virulence genes such as stx1 (81.81%), elt (86.66%), and eae (66.66%) along with resistance gene for ampicillin (CITM) (80%), quinolones (qnrB) (44.44%), tetracycline (tetO) (66.66%), and streptomycin (aadA1) (66.66%). The data indicates a high incidence rate of multiple antibiotic resistant enteric bacteria in the spring water of Sikkim. Additionally, the presence of enteric bacteria in the water samples indicates widespread fecal contamination of the spring water. © Copyright © 2020 Singh, Das, Kumar, Gajamer, Najar, Lepcha, Tiwari and Singh.
Effect of Humidity on Pest and Disease Incidence in Crops
(Apple Academic Press, 2025) Ramkumar; Manisha Chaudhary; Prince Sahu; Kartikey Singh; Ravi Kumar; Anju Shukla; Chander Singh; Vishal Dinkar; Ashish Kumar Singh; Niharika Singh; Ram Keval; Anshuman Semwal; Rishi Nath Pandey
Humidity is a term used to describe how much moisture or water vapor is present in an atmosphere. It is a crucial environmental factor in the emergence, growth, and development of diseases and pests. Insects have a greater ability for reproduction, and high humidity has an impact on their physiology. There are several differences in how ambient moisture affects an insect’s metabolic rate. It may have an impact on insect behavior such as post-diapause egg hatching, molting, mating, and pest movement. Dry environments trigger diapause, but moist ones promote the growth and pupation of insect pests. With a maximal rate of disease progress at intermediate RHs (50–56%), disease development is often faster at close to room temperature. Low RH levels speed up host tissue death, inhibit disease progression, and limit spore germination and lesion growth. Within a range of suitable temperatures, intermediate RH levels enhance disease progression by increasing spore germination. Although prolonged exposure to these conditions seems to be detrimental for the development of disease, high RH enhances spore germination. Epidemics of disease, the prevalence of pests, and the use of pesticides are all influenced by weather conditions, especially high ambient humidity. Soil moisture and temperature have a considerable impact on the emergence and spread of nematodes and plant diseases. The population growth, survival, and incidence of nematodes are influenced by humidity. When egg-laying in a dry environment, mites produce more eggs more quickly and live longer than when doing so in a nearly saturated environment. In a moist environment, newly hatched mites have a limited chance of survival. At higher RH levels (>96%) with a well-defined incubation period, entomopathogenic agents exhibit their highest infection potential and mortality rates. © 2025 by Apple Academic Press, Inc.
Effect of pH and hydrocolloids on the thermal stability of whey proteins in model beverage system
(2005) Sudhir Singh; Ashish Kumar Singh; Abhay Kumar
In the preparation of whey-based beverages denatured whey proteins adversely affect the aesthetic quality of product. It was envisaged to stabilize cheese-whey and paneer-whey beverage systems at different adjusted pH (3.5-4.5) using hydrocolloids such as carboxymethyl cellulose (CMC), pectin, guargum and carrageenan at 0.1 to 0.25% levels. All the stabilizers had a significant (p<0.01, CD-0.061) influence on stabilization of whey proteins. CMC at 0.15% level and pH of 3.5 afforded maximum stabilization of cheese-whey proteins whereas, 0.25% of CMC at pH 3.5 exerted maximum stabilization to paneer-whey proteins. The stabilization effect of stabilizer on whey system was maximum at pH 3.5, which decreased with increase in pH to 4.5. Carrageenan (0.2%) at pH 4.5 and 0.1% carrageenan at pH 4.5 afforded least stability to cheese and paneer-whey systems, respectively. The stabilizing effect of stabilizer usually showed progressive increase with increase in the level of addition from 0.1 to 0.2%; at 0.25% level carrageenan and pectin showed maximum stability. Guargum, however, did not show a specific trend. The overall sensory score of both the whey systems containing stabilizers decreased in the order: CMC, pectin, guargum and carrageenan. CMC at 0.15-0.25% level and pH of 3.5 successfully stabilizes cheese and paneer-whey systems.
Evaluating the efficacy of insecticides against major insect pest threats on pigeonpea in Eastern Plain Zone of Uttar Pradesh
(Malhotra Publishing House, 2025) Krishna Kant Prajapati; Ramkumar Niranjan; Ram Keval; Ashish Kumar Singh
The efficacy of seven insecticides was evaluated against major insect pests on long-duration pigeonpea crop. The results showed that Thiamethoxam 25 WG was the most effective against tur pod fly with the lowest maggot population, pod damage (23.33%), and grain damage (11.94%). Flubendiamide 480 SC resulted in the lowest larval population of gram pod borer, with the least pod and grain damage (0.67% and 0.21%, respectively). Thiamethoxam 25 WG also recorded the lowest bug population, pod damage, and grain damage in the case of tur pod bugs. The highest grain yield (1065.63 kg/ha) was achieved with Thiamethoxam 25 WG, followed by Flubendiamide 480 SC (1038.67 kg/ha). Thiamethoxam 25 WG also had the highest incremental cost-benefit ratio (1:7.04), followed by Flubendiamide 480 SC (1:5.06). Based on these results, Thiamethoxam 25 WG and Flubendiamide 480 SC can be recommended for controlling the key insect pests of pigeonpea in Eastern Plain Zone of Uttar Pradesh. © 2025, Malhotra Publishing House. All rights reserved.