Browsing by Author "Gaurav Sharma"

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A cross-sectional study to assess the quality of life, depression, anxiety and stress levels after 45 days covid-19 lockdown
(Radiance Research Academy, 2020) Kashif Ali; Umamah Mufti; Gaurav Sharma; Aliya Mufti
Rationale: The COVID-19 or the coronavirus is a highly contagious viral disease which spread from humans to humans through small droplets via Nose, Mouth, Cough, or exhales infected more than 3.76 million peopleacross 185 countries. Objective: We aim to assess the Quality of life, depression, anxiety, stress levels in the Indian population due to COVID-19 and to find out the demographic groups which need more attention for the prevention of mental illness. Methods: Participants were recruited through proliferative approach with aid of social media platforms and an online survey was conducted to assess knowledge about covid-19, Quality of life (WHQOL), Depression, Anxiety and Stress Scale (DASS-21). Statistical analysis by SPSS-2 was done and unpaired t-test was used to analyse the influence of lockdown on quality of life, depression and anxiety in the participants. Results: 847 participants filled the questionnaire 64.1% participants have some knowledge and 35.9% have full knowledge about COVID-19. We found a significant difference in the WHOQOL & DASS-21 between the male and female participants (p=0.0001) and age (18-39 years & 40-64 years) (p=0.0001). There was significant difference in the WHOQOL(p= 0.0002)& DASS-21(p=0.0001)with education level (bachelors and above or without bachelors) and occupation (government job/ private job) WHOQOL (p=0.0001) DASS-21(0.0001). There was no significant difference between the average monthly family income groups (p > 0.05). Participants of majority and other religious groups showed a significant difference in WHOQOL (p=0.0001) and DASS-21 score (p=0.0001). Conclusion: The government should focus on encouraging people for stress-free lifestyle by taking care of their livelihood, daily needs and social messages focusing on family support. Necessary measures need to be taken to increase awareness about covid-19 prevention and removing misconception regarding the association of the disease with any community. © IJCRR.
A novel tunable metal-clad planar waveguide with 0.62PMN-0.38PT material for detection of cancer cells
(John Wiley and Sons Inc, 2023) Rajiv Maurya; Ankit Mishra; Chandan Singh Yadav; Abhishek Upadhyay; Gaurav Sharma; Sushil Kumar; Vivek Singh
A dynamically tunable metal clad planar waveguide having 0.62PMN-0.38PT material is simulated and optimized for detection of cancer cells. Angular interrogation of the TE0 mode of waveguide shows that critical angle increases greater than the resonance angle with increasing of cover refractive index, which limits the detection range of waveguide. To overcome this limitation, proposed waveguide applies a potential on the PMN-PT adlayer. Although a sensitivity of 105.42 degree/RIU was achieved at 70 Volts in testing the proposed waveguide, it was found that the optimal performance parameters were obtained at 60 Volts. At this voltage, the waveguide demonstrated detection range 1.3330–1.5030, a detection accuracy 2393.33, and a figure of merit 2243.59 RIU−1, which enabled the detection of the entire range of the targeted cancer cells. Therefore, it is recommended to apply a potential of 60 Volts to achieve the best performance from the proposed waveguide. (Figure presented.). © 2023 Wiley-VCH GmbH.
Acoustically induced forbidden electromagnetic band gaps
(Springer, 2023) Suraj Prakash; Souryadipta Maiti; Gaurav Sharma; Vivek Singh
Lamb wave’s perturbation effect on electromagnetic modes propagating in Y − X lithium niobate slab is theoretically investigated. Rayleigh Lamb dispersion curves are estimated to investigate the behaviour of Lamb waves in micrometer order thick slab. Utilizing the information obtained from dispersion curves, acoustic displacement patterns and strain generated along the plate are evaluated. The modification caused to the refractive index of lithium niobate due to Lamb wave induced strain with photoelastic effect is determined. Further, the features of acoustically modified refractive index are examined using the transfer matrix method. It is found that an acoustically modified refractive index offers forbidden electromagnetic band gaps that can be adjusted by tuning the frequency of Lamb waves and by changing the incidence angle of electromagnetic waves. Hence proposed structure is used as a dynamically tunable photonic crystal for various applications like optical filters and optical switches. © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Acoustically tunable photonic band gap generation in MgO doped Lithium Niobate micro-dimension plate
(Academic Press, 2018) Suraj Prakash; Gaurav Sharma; Gulab Chand Yadav; Vivek Singh
Refractive index contrast generation in MgO doped LiNbO3 plate via Lamb wave perturbation for induction of acoustically tunable photonic band gap is theoretically studied. Fundamental symmetric Lamb mode is excited in micro dimension thin plate structure to produce symmetric disturbance for periodic contraction and rarefaction along the length of plate. Effect of contraction and rarefaction on production of refractive index contrast is studied using photo–elastic effect. The generated quasi static low–high optical index region in plate modifies electromagnetic wave propagation and provides photonic band gaps, which are investigated using Bloch's theorem and transfer matrix method. The induced photonic band gap shows great dependency on optical contrast and unit cell dimension created by acoustic frequencies. These acoustically tunable photonic band gaps have rewarding applications in acousto optical devices, laser and sophisticated sensing. © 2018 Elsevier Ltd
Common path interferometeric analysis of a planar polymer optical waveguide having adlayer of 2D materials for biosensing applications
(Springer, 2021) Abhishek Upadhyay; Chandan Singh Yadav; Gaurav Sharma; Sushil Kumar; Vivek Singh
Sensitivity of a planar polymer optical waveguide having adlayer of MoS2, WS2, MoSe2, WSe2 are estimated using common path Mach-Zehnder interferometer analyses. Dispersion relation and reflectivity equation of proposed waveguide is obtained by matching the electric and magnetic field at various boundaries. The obtained cutoff film thickness of the waveguide is approximately same in the presence of monolayer thickness of transition metal dichalcogenides materials. The cutoff film thickness 84.2 nm of this waveguide is approximately same for TE0, TM0 mode at wavelength 300 nm, these cutoff film thicknesses increases and become 304.6 nm at 1200 nm wavelength. In the proposed common path interferometer analysis, the superposition of TE0 and TM0 modes is considered as sensing signal. It is observed that the difference of their propagation constant is slightly decreased with increase of cover refractive index. Further the maximum phase change is obtained near the propagation constant maxima value hence around this value the output interference signal shows maximum shift with cover refractive index. In the considered wavelength range the maximum sensitivity 0.019 is obtained at wavelength 936nm, when a monolayer of WSe2 material is used as adlayer. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Comparison of contrasts in rainfall and drought characteristics in the Chambal basin in Madhya Pradesh and Rajasthan
(IWA Publishing, 2021) Gaurav Sharma; T. Thomas; R.M. Singh
The availability of water resources is under stress due to its unsustainable exploitation. The Chambal basin is located in the water-scarce region in India with average annual rainfall varying between 687.1 mm in the Rajasthan (RJ) region and 938.2 mm in the Madhya Pradesh (MP) region. On average, there are 48 rainy days in the MP region and 39 rainy days in the RJ region of the Chambal basin. Fourteen drought years have been identified during the period spanning 34 years (1985–2018). 44% of basin area located in the MP region and 54% of basin area located in the RJ are found to be drought-prone. The Standardized Precipitation Index-based evaluation of drought characteristics indicated higher drought frequency in the RJ region varying between 1 in 3 years and 1 in 4 years and between 1 in 3 years and 1 in 5 years in the MP region, which has also been substantiated by the Relative Departure Index (RDI), namely average RDI for RJ (0.69) and MP (0.58). The understanding of the contrasts in rainfall and drought characteristics in upper reaches (MP region) and lower reaches (RJ region) of the Chambal basin will help in holistic management and sharing of water resources based on these contrasts and constraints. © 2021 by the authors.
Controlling the band structures and electromagnetic density of modes in one-dimensional photonic crystals with Lamb wave
(Taylor and Francis Ltd., 2022) Ayush Aman; Surendra Prasad; Suraj Prakash; Gaurav Sharma; Vivek Singh
We have modeled and investigated band structures and the electromagnetic density of modes in one-dimensional photonic crystal whose refractive index is modulated by the excitation of the fundamental symmetric mode of Lamb wave using the Wigner phase time approach and transfer matrix method. The Rayleigh–Lamb dispersion curves are plotted to select the proper thickness of each sub-layer of considered photonic crystal structure which is comprised of silica (SiO2) and rutile (TiO2) layers as sub-layers of unit cell. The propagation of Lamb wave into the considered structures produced phononic band gaps in gigahertz frequency for acoustic waves. Also, the propagation of Lamb wave into the considered structures causes compression in SiO2 and dilation in TiO2 or vice versa, which can further increase or decrease the refractive index of both layers. Thus, there can be three combinations of change in refractive indices: case 1 (both layers have an unperturbed refractive index), case 2 (maximum change of the refractive index in SiO2 and minimum change in the refractive layer of TiO2), and case 3 (minimum change of the refractive index in SiO2 and maximum change in the refractive layer of TiO2). The band gap structures of considered structures are plotted for both polarized electromagnetic waves. © 2020 Informa UK Limited, trading as Taylor & Francis Group.
Coupled mode surface plasmon resonance sensor: in situ detection of humidity with starch biofilm
(Springer New York LLC, 2018) Gulab Chand Yadav; Gaurav Sharma; Vivek Singh; Manindra Kumar; Neelam Srivastava; Sushil Kumar; Vinay Gupta
An environment friendly coupled mode surface plasmon resonance sensor structure with starch biofilm as sensing element for humidity detection of environment is fabricated and demonstrated. The surface plasmon resonances were created using PVC layer fabricated between silver and starch biofilm on a rectangular prism. The analyses of fabricated sensor have been done by both wavelength and angular interrogation methods. The proposed sensor has maximum sensitivity 0.45 nm/%RH in wavelength interrogation method and 0.09°/%RH in angular interrogation method. Here the variations in humidity of environment, changes the refractive index of starch biofilm and hence in the surface plasmon resonances. Also, the proposed sensor shows a linear variation in resonance wavelength and resonance angle with respect to the variation in humidity of environment. © 2017, Springer Science+Business Media, LLC, part of Springer Nature.
Design of Si–SiO2 phoxonic crystal having defect layer for simultaneous sensing of biodiesel in a binary mixture of diesel through optical and acoustic waves
(Maik Nauka-Interperiodica Publishing, 2017) Gaurav Sharma; Sushil Kumar; Vivek Singh
The potentiality of a phoxonic crystal for sensing of biodiesel in a binary mixture of diesel and biodiesel is theoretically investigated. Using the transfer matrix method, the transmission of acoustic and optical waves through a periodic one-dimensional crystal of Si–SiO2 layers is studied. A pass band is created in the band gap region by introducing a cavity in the considered one-dimensional crystal structure. This pass band can also be considered as a defect mode, and it is found that its position is highly dependent on mole concentration of binary mixture of biodiesel and diesel present in the cavity. The sensitivity of the sensor for a binary mixture of biodiesel and diesel in the cavity with various mole concentrations is estimated. Simulated results provide a valuable guidance for designing a phoxonic crystal sensor consisting of a defect layer. © 2017, Pleiades Publishing, Ltd.
Detection of aqueous nitro explosives using SPR sensors integrated with D-shaped optical fibers
(Springer, 2025) Abhishek Upadhyay; Gaurav Sharma; Rajiv Maurya; Ankit Mishra; Vivek B. Singh
This study presents an optimization and simulation of a surface plasmon resonance-based optical fiber sensor with a D-shaped configuration, for the precise detection of aqueous nitro explosive. The proposed sensor undergoes simulation and analysis using finite element techniques. Optimization of the Au layer thickness, with a 30 nm layer identified for maximum SPR curve reflection, Subsequently, a polyaniline layer was applied to enable selective detection. Varying sample concentrations interact uniquely with the polyaniline sensing surface, as concentration increases, the SPR dip shifts toward longer wavelengths like red-shift in the spectra. Simulating sensor lengths ranging from 1 to 5 mm provides valuable insights into sensor responses, showing improved detection accuracy and figure of merit as the sensor length decreases. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.
Detection of kerosene adulteration in automobile fuel with a novel metal clad planar waveguide
(Elsevier Ltd, 2019) Gulab Chand Yadav; Suraj Prakash; Gaurav Sharma; Sushil Kumar; Vivek Singh
A metal clad planar waveguide having hollow prism filled with adulterated petrol and diesel is fabricated and studied. The confinement of electromagnetic radiation in the film region of proposed structure under resonance condition is large. Observed variation in refractive index of considered automobile fuel is linear with change of percentage concentration of kerosene. Estimated sensitivity of proposed sensor is compared with fabricated sensor for both adulterated automobile fuel. The experimentally obtained maximum sensitivity 105.24 degree/RIU for adulterated petrol and 182.68 degree/RIU for diesel are in good agreement with their respective theoretically obtained maximum sensitivity 105.88 degree/RIU and 190.00 degree/RIU. Also, this study shows that the stability of present approach is high. © 2019 Elsevier Ltd
DRESS Syndrome with Cold Agglutinins: An Unusual Immune Response to Anticonvulsants
(Bentham Science Publishers, 2025) Sumit Jaiswal; Sourabh Pathania; Gaurav Sharma; Ankur Singh; Upinder Kaur; Anup P. Singh; Sankha Shubhra Chakrabarti
Introduction: DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms) is a rare adverse drug reaction characterized by cutaneous and systemic manifestations, with a mortality rate of up to 10%. In this study, we describe the case of a 77-year-old man who developed DRESS syndrome with cold agglutination. Case Presentation: A 77-year-old man prescribed phenytoin and carbamazepine for suspected cranial neuralgia after a tooth extraction developed high-grade fever and hemorrhagic crusting on the upper and lower lips and oral mucosa, morbilliform rashes over the chest, abdomen, and back along with facial edema, all occurring over 2 weeks. Clinically significant right-sided submandibular, cervical, and axillary lymphadenopathy was observed. Additional findings, including peripheral blood eosinophilia, hepatitis, and coagulopathy, helped us make a provisional diagnosis of DRESS syndrome. The peripheral blood smear showed an incidental finding of cold agglutination phenomenon at room temperature (16 °C; winter months in North India), which disappeared under warmer conditions. However, gross hemolysis was not confirmed. The patient showed significant response in both clinical and hematological parameters within 24 hours of initiating intravenous dexamethasone, which was continued and gradually tapered over 14 days. Follow-up at one month showed the disappearance of the cold agglutination phenomenon. Conclusion: Cold agglutination in DRESS syndrome has not been documented in detail in the past. One hypothesis is the agglutination of red blood cells (RBCs) due to the effect of the pathogenetic antibodies in DRESS syndrome directed against RBC antigens. Further molecular research may elucidate the pathways of this rare clinical finding. © 2025 Bentham Science Publishers.
Dynamic modulation of refractive index in Y-X LiNbO3 slab through lamb wave
(Institute of Electrical and Electronics Engineers Inc., 2018) Suraj Prakash; Gaurav Sharma; Gulab Chand Yadav; Vivek Singh
Refractive index contrast generation, due to induced modulation of refractive index in Y-X LiNbO3 slab by Lamb wave has been studied theoretically. Acoustic frequency and corresponding wavelength is chosen to excite S0 Lamb mode in 400nm thick slab using Rayleigh-Lamb frequency relations. Propagation of Lamb wave produces strain in the slab and modulates refractive index. This modulation is responsible to produce refractive index contrast. Sinusoidal variation of refractive index has been found in slab with a period equals to wavelength of excited Lamb mode. The obtained maximum variation in refractive index along X is of order 0.0166 with respect to unperturbed value 2.28 in 400nm thick Y-X LiNbO3 slab at 5GHz Lamb wave frequency. These contrast variations along both X and Y directions decrease with increase in slab thickness. © 2017 IEEE.
Effect of a graded optical layer on surface plasmon resonance sensor
(2014) Sushil Kumar; Gaurav Sharma; Vivek Singh
The sensitivity, detection accuracy and quality parameter of a surface plasmon resonance sensor containing a graded optical layer are studied. The reflectivity of exponential graded profile and Gaussian graded profile optical layers are derived using the transfer matrix method. The obtained results of the considered graded profiles are compared with each other and it is found that the exponential graded profile gives better results than the Gaussian graded profile. Also, by comparing these results with a uniform surface plasmon resonance sensor, it is observed that the overall performance of the sensor is improved by introducing graded optical layers. © 2013 Published by Elsevier B.V.
Enhancement of Photonic Band Gap in a Si- SiO2 Phoxonic Crystal Through a Lamb Wave
(Springer Netherlands, 2017) Gaurav Sharma; Sushil Kumar; Vivek Singh
The occurrence of a photonic band gap modulation in the periodic arrangement of a Si-SiO2 layer, in the presence of in-plane acoustic plate symmetric modes is studied. The proposed structure shows simultaneous existence of photonic band gaps in the infrared region and phononic band gaps in the GHz frequency range. Due to the presence of photonic band gaps and phononic band gaps, this arrangement is called a phoxonic crystal. The optical forbidden band shifted towards lower frequency by acoustooptic interaction. It is also found that the optical forbidden band is increased through an acoustic plate symmetric mode of submicron wavelength in the proposed Si-SiO2 structure. © 2015, Springer Science+Business Media Dordrecht.
Estimation of acoustically induced refractive index perturbation in silicon and germanium slab for optical applications
(Technical University of Wroclaw, 2015) Gaurav Sharma; Sushil Kumar; Dinesh Kumar; Vivek Singh
In-plane displacement field and refractive index variation for silicon and germanium in the presence of Lamb wave is estimated for optical applications. The required dispersion equation in a thin silicon and germanium plates is obtained using the method of potentials with boundary conditions involving the bulk and surface stress of the materials considered. The eigen-values thus obtained are used to compute the Lamb wave modes for the slab of silicon and germanium at same thickness. The fundamental anti-symmetric and symmetric plate modes and their overtones are observed due to confinement of acoustic energy within the slab thickness. In addition, the excited symmetric modes in silicon have longer wavelengths than those of germanium at a fixed frequency. Therefore, the refractive index modulation through the Lamb wave in silicon is always larger as compared to that of germanium. This refractive index modulation can be treated as periodic sinusoidal refractive index variation and may be considered as a tunable one-dimensional photonics crystal.
Estimation of cover sensitivity of a planar polymer waveguide through double path broadband difference interferometeric analysis
(Elsevier GmbH, 2020) Abhishek Upadhyay; Chandan Singh Yadav; Gaurav Sharma; Vivek Singh
Broadband difference interferometeric analysis of a double path planar polymer optical waveguide is presented for bio-sensing applications. Mathematical formulation of intensity of output signal is obtained using interferometeric analysis. Further, the dispersion equation is obtained by matching the field at core cladding interface that gives the cutoff film thickness for TE0 and TM0 modes in considered spectral range. The waveguide is analyzed by propagating either same polarized (TE[sbnd]TE or TM[sbnd]TM) modes or unlike polarized (TE[sbnd]TM) modes in the reference arm and sensing arm. It is observed that difference of propagation constant for same polarized mode increases with increase of wavelength while for unlike polarized modes it first increases up to a maximum value and then decreases in the considered wavelength range. The maxima of output interference signal shifted prominently with the cover refractive index for the wavelength range near the maximum value of propagation constant difference. The obtained sensitivity 9.226 for unlike polarized modes in arms is much larger than the sensitivity 0.071 of same polarized modes in arms. © 2020 Elsevier GmbH
Estimation of photonic band gap in silicon crystal waveguide through acousto-optic interaction
(Springer Science and Business Media, LLC, 2015) Gaurav Sharma; Sushil Kumar; Surendra Prasad; Vivek Singh
The photonic band gap through acousto-optic interaction in a face-centred cubic silicon crystal is theoretically studied. The dispersion relation for acoustic wave is obtained using method of potentials with boundary conditions involving the bulk and surface stress of considered materials. The dispersion relation for optical wave is derived by transfer matrix method and boundary conditions based on electromagnetic theory. Observation shows that the central frequency of photonic band gap in silicon crystal can be chosen in any desired infrared optical frequency range by adjusting the frequency of acoustic wave. Also, the size of these band gaps in chosen optical frequency range can be further tuned through incident angle of light wave. This study may provide an efficient method to obtain tuneable photonic crystal. © Springer Science+Business Media New York 2015.
Experimental detection of chlorpyrifos by MoS2 coated planar polymer waveguide sensor utilizing common path interferometric principle
(Elsevier GmbH, 2023) Abhishek Upadhyay; Chandan Singh Yadav; Rajiv Maurya; Gaurav Sharma; T. Sonamani Singh; Sushil Kumar; Vivek Singh
A common path Mach-Zehnder interferometer is fabricated using a planer polymer waveguide having MoS2 as an adlayer for chlorpyrifos detection. The dispersion characteristic and cutoff condition of proposed waveguide are obtained theoretically and hence the cutoff film thickness is optimized to get TE0 and TM0 propagating modes. Variations between the phase shift of propagating modes with the concentration of pure chlorpyrifos and its commercial sample are obtained. A good linear variation between phase shift and concentration of chlorpyrifos is obtained in our fabricated waveguide for all considered temperatures. The obtained maximum sensitivity, minimum limit of detection, and limit of quantification of chlorpyrifos are 5.66 degree/μM, 1.57 μM, and 5.24 μM respectively, at 45° C. The capability of the fabricated sensor to generate distinct response for a pure and commercial sample of chlorpyrifos at different concentration and temperature were confirmed by principal component analysis. Since the response of sensor is better for commercial samples at a lower temperature, therefore it is recommended that the concentration of chlorpyrifos in commercial samples should be measured at low temperatures. © 2023 Elsevier GmbH
Expression analysis of hormonal pathways and defense associated genes in gamma-rays mutagenized wheat genotypes against combined stresses of spot blotch and terminal heat
(Elsevier B.V., 2022) G Mahendra Singh; SrinathaReddy S; Gaurav Sharma; Suman Bakshi; Uttam Kumar; Pradeep Bhati; Sanjay J. Jambhulkar; Ramesh Chand; Arun K. Joshi; Vinod K. Mishra; Sandeep Sharma
Wheat (Tritium aestivum L.) productivity is severely hampered by various pathogens and changing climatic conditions. Spot blotch and terminal heat stress are the major constraints of wheat production in the eastern Gangetic plains of India. To identify novel breeding sources and to understand underlying resistance mechanisms, forty-four gamma rays mutagenized wheat genotypes, derived from three different parents were screened under favourable agro-ecological conditions for spot blotch and terminal heat stress. Ten mutants showed reduced spot blotch infection calculated based on Area Under Disease Progress Curve (AUDPC), than their respective parents. The mutant TAW41 had the least infection (AUDPC: 354.32), significantly lower than its parent HD2967 (AUDPC: 675.51) and other checks. TAW41 also had a higher Normalized Difference Vegetation Index (NDVI) and chlorophyll content than the parent. Gene expression analysis of TAW41 showed differential accumulation of transcripts involved in hormonal pathways (Salicylic acid, Jasmonic acid, and ethylene) and other defense-associated genes, indicating that TAW41 might have unique resistance mechanism that facilitates this genotype to perform better against the combined stress of spot blotch and terminal heat. Hence, mutant TAW41 has been identified as a novel source of resistance that could be exploited in wheat improvement programmes to enhance tolerance to spot blotch and terminal heat stress. © 2021 The Authors