Browsing by Author "S.P. Singh"

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2.45-GHz microwave irradiation adversely affects reproductive function in male mouse, Mus musculus by inducing oxidative and nitrosative stress
(Informa Healthcare, 2014) S. Shahin; V. Mishra; S.P. Singh; C.M. Chaturvedi
Electromagnetic radiations are reported to produce long-term and short-term biological effects, which are of great concern to human health due to increasing use of devices emitting EMR especially microwave (MW) radiation in our daily life. In view of the unavoidable use of MW emitting devices (microwaves oven, mobile phones, Wi-Fi, etc.) and their harmful effects on biological system, it was thought worthwhile to investigate the long-term effects of low-level MW irradiation on the reproductive function of male Swiss strain mice and its mechanism of action. Twelve-week-old mice were exposed to non-thermal low-level 2.45-GHz MW radiation (CW for 2 h/day for 30 days, power density = 0.029812 mW/cm2 and SAR = 0.018 W/Kg). Sperm count and sperm viability test were done as well as vital organs were processed to study different stress parameters. Plasma was used for testosterone and testis for 3β HSD assay. Immunohistochemistry of 3β HSD and nitric oxide synthase (i-NOS) was also performed in testis. We observed that MW irradiation induced a significant decrease in sperm count and sperm viability along with the decrease in seminiferous tubule diameter and degeneration of seminiferous tubules. Reduction in testicular 3β HSD activity and plasma testosterone levels was also noted in the exposed group of mice. Increased expression of testicular i-NOS was observed in the MW-irradiated group of mice. Further, these adverse reproductive effects suggest that chronic exposure to nonionizing MW radiation may lead to infertility via free radical species-mediated pathway. © 2014 Informa UK, Ltd.
2.45GHz (CW) Microwave irradiation alters circadian organization, spatial memory, DNA structure in the brain cells and blood cell counts of male mice, mus musculus
(Electromagnetics Academy, 2011) Chandra Mohini Chaturvedi; V.P. Singh; P. Singh; P. Basu; M. Singaravel; R.K. Shukla; A. Dhawan; A.K. Pati; R.K. Gangwar; S.P. Singh
Present study examines biological effects of 2.45 GHz microwave radiation in Parkes strain mice. Forty-day-old mice were exposed to CW (continuous wave) microwave radiation (2 h/day for 30 days). Locomotor activity was recorded on running wheel for 12 days prior to microwave exposure (pre-exposure), 7 days during the first week of exposure (short-term exposure) and another 7-day spell during the last week of the 30-day exposure period (long-term exposure). Morris water maze test was performed from 17th to 22nd day of exposure. At the termination of the exposure, blood was processed for hematological parameters, brain for comet assay, epididymis for sperm count and motility and serum for SGOT (serum glutamate oxaloacetate transaminase) and SGPT (serum glutamate pyruvate transaminase). The results show that long-term radiation-exposed group exhibited a positive ψ (phase angle difference) for the onset of activity with reference to lights-off timing and most of the activity occurred within the light fraction of the LD (light: dark) cycle. Microwave radiation caused an increase in erythrocyte and leukocyte counts, a significant DNA strand break in brain cells and the loss of spatial memory in mice. This report for the first time provides experimental evidence that continuous exposure to low intensity microwave radiation may have an adverse effect on the brain function by altering circadian system and rate of DNA damage.
A comparison of proline, thiol levels and GAPDH activity in cyanobacteria of different origins facing temperature-stress
(2005) A.P. Singh; R.K. Asthana; Arvind M. Kayastha; S.P. Singh
Three cyanobacterial strains originating from different habitats were subjected to temperature shift exposures and monitored for levels of proline, thiol and activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Thermophile Mastigocladus laminosus (growth optimum, 40°C), raised the proline level 4.2-fold at low temperature (20deg;C), for the psychrophile Nostoc 593 (growth optimum, 20°C), it was raised 8-fold at 40°C while in the mesophile Nostoc muscorum (growth optimum, 30°C), the imino acid level increased 2.3-fold during temperature 'shiftdown' to 20°C or 3.5-fold in sets facing 'shiftup' (40°C). Alterations in thiol levels in the above strains were in line with proline. It is suggested that such fluctuations reflect metabolic shifts as a response to stress. Interestingly, GAPDH activity was maximum at the respective growth temperature optimum of M. laminosus (122 nmol NADPH oxidized min-1 mg-1 protein) and Nostoc 593 (141 nmol NADPH oxidized min-1 mg-1 protein) while in N. muscorum, it increased at 40°C (101 nmol NADPH oxidized min-1 mg-1 protein) and to 93.3 nmol NADPH oxidized min-1 mg-1 protein (20°C) relative to 86 nmol NADPH oxidized min -1 mg-1 protein at 30°C. It seems that extremophiles maintain the GAPDH activity/level during growth at their respective temperatures optimal while the mesophile increases it in order to cope up with temperature-stress.
A proteomic approach to understand the tripartite interactions between plant-trichoderma-pathogen: Investigating the potential for efficient biological control
(Springer International Publishing, 2016) Chetan Keswani; Kartikay Bisen; S.P. Singh; B.K. Sarma; H.B. Singh
Efficient biological control of plant diseases involves successful interactions among plant, biocontrol agents, and pathogens. Trichoderma spp. being the most popular and successful biocontrol agents are predominantly used to protect plants against a broad range of phytopathogens. However, a better understanding of the tripartite relationship established among Trichoderma-plant-pathogen is necessary in order to advance the practical applicability in agroecosystems and to unveil the cross talk involved in this beneficial association. Moreover, comprehensive knowledge of this three-way association is also required to identify the effective strain of Trichoderma to be used for efficient plant disease control. In this regard, several approaches have been adapted to study these tripartite interactions at molecular level such as transcriptomics, proteomics, and metabolomics. Although transcriptomic approach generates huge data, the study is incomplete without involving proteomic aspect, as it is directly responsible for cellular activity. Therefore, implication of proteomics in studying plant-pathogen interaction is now gaining noteworthy attention. Recently, proteomic approach has been found to contribute successfully in recognizing and characterizing the major proteins playing key role in inducing the defense mechanism in plants against pathogen attack. Nevertheless, empathizing proteomics of Trichoderma spp. can be used to discover novel determinants that would be helpful in developing new biocontrol formulation with enhanced biocontrol potential. Moreover, strain improvement using such determinants could also be achieved. In addition, proteomic study of the pathogen in this interaction is of great interest, as it would give insight into two aspects: firstly, the major factors contributing to the pathogenicity and secondly, targeting such factors for diminishing the pathogenicity. Therefore, in this chapter we focus our attention on highlighting the recent advances and findings regarding the proteomic approach used to study tripartite interaction between Trichoderma-plant-pathogen. © Springer International Publishing Switzerland 2016.
A technique for preparing mechanically strong ohmic contacts on glass slides
(1981) U.K. Chaturvedi; S.K. Agrawal; A.K. Nigam; S.P. Singh
[No abstract available]
A technique to improve the convergence of fdlf for systems with high r/x lines
(Institute of Electrical and Electronics Engineers Inc., 1991) S.P. Singh; G.S. Raju; V.S. Subba Rao
A technique to improve the convergence of FDLF for systems with high R/X lines has been suggested in this paper. It is proposed that a slack bus which has the minimum sum of the squares of deviations of bus voltage angles will give the better convergence properties of FDLF compared to any other bus as the slack node. This is demonstrated by taking examples of variety of systems. This technique is implemented on BX version of FDLF. © 1991 IEEE.
Absorption spectrum of Mn3+ and redox equilibria of iron and manganese in sodium silicate glass
(1992) S.P. Singh; A. Kumar
The absorption characteristics of the manganic ion in a 30Na2O, 70SiO2 glass were investigated and the molar extinction coefficient of the Mn3+ ion was calculated to determine accurately the intensity of its band for the first time in a silicate glass. The value of εMn(3+) was found to be of the order of around 140 g mole l-1 cm-1 at its wavelength maximum of approximately 500 nm in the glass, which is within the range ε ≈ 1 × 10-2-2 × 102 g.mole l-1 cm-1 as expected for the ligand field transition. The concentration of Mn3+ ions as measured by optical spectroscopy agreed well with that determined chemically within an experimental error of ±5%. The Mn2+: Mn3+ and Fe2+: Fe3+ equilibria in a sodium silicate glass containing equimolar concentrations of total manganese and iron were established optically and chemically in a Pt-1%Rh crucible in air at 1250 and 1400°C, respectively. The loss of total iron from the glass melt at these temperatures was observed and discussed. The redox equilibria were found thermodynamically to shift more towards the reduced states in the molten glass with increasing temperature. The [ferric]: [ferrous] equilibrium ratios were found to be around 80 and 70 times greater than the [manganic]: [manganous] ratios at 1250 and 1400°C, respectively under identical conditions. The results were attributed to the various properties of redox ions such as ionisation potential, ionic radius, electronic configuration, redox potential, and stereochemistry of the metal ions as well as to the polarisability of the oxygen ligands and the nature of the glass.
Accumulation in Wood: A Nutrient-conserving Strategy of Tropical Forests
(1985) S.P. Singh; R.K. Khanna; J.S. Singh
[No abstract available]
Action of heavy metals on hill activity and O2 evolution in Anacystis nidulans
(1987) D.P. Singh; S.P. Singh
Addition of 5 micromolar Cu2+, Cd2+, and Zn2+ was inhibitory to 10 micromolar H2O2-supported Hill activity (dichlorophenolindophenol reduction) and O2 evolution in membrane preparation from Anacystis nidulans. The reversal of Cd2+ and Zn2+ inhibition, in contrast to Cu2+, by exogenously added catalase (EC 1.11.1.6) suggested that the former cations were inhibitory to H2O2 degradation. Ascorbic acid (20 micromolar) supported 27% of the Hill activity which was intensitive to DCMU (10 micromolar) and the remaining activity, attributable to the DMCU sensitive process, was sensitive to inhibition by Cu2+ only. It is suggestive that the action site of Cd2+ and Zn2+ is located between the electron donation sites of H2O2 and ascorbic acid, while that of Cu2+ is located beyond it. Electron donation by reduced glutathione was insensitive to DCMU and Cu2+, indicating that the action site of Cu2+ is prior to its electron donation site. Further, the phenanthroline (10 micromolar) reversal of Cu2+ inhibition of Hill activity suggested a tentative action site of Cu2+ at the level of cytochrome.
ADAPTIVE CONTROL OF GENERATOR EXCITATION.
(IEEE, 1987) S.K. Panda; S.P. Singh; V.V. Chalam
The application of an adaptive self-tuning regulator for generator excitation is discussed. Terminal voltage error and speed error are combined, using variable weighting factors, to obtain a single signal. This signal is fed simultaneously to the regulator and the identification block. The algorithm used for the regulator is based on minimum-variance control strategy and is computed from an online estimated model of the generating unit using recursive-least-squares identification. Experimental results show that the regulator provides excellent damping for varying operating conditions and various types of disturbances such as step change in prime-mover speed, sudden loss of a transmission line, step change in reference voltage, sudden change in large loads, among others. 4 refs.
Additional evidence of stable EMF-induced changes in water revealed by fungal spore germination
(1994) S. Rai; U.P. Singh; G.D. Mishra; S.P. Singh; Samarketu
[No abstract available]
Additional evidence of stable EMF-induced changes in water revealed by fungal spore germination
(Informa Healthcare, 1994) Subas Rai; U.P. Singh; G.D. Mishra; S.P. Singh; Samarketu
Spore germination of some fungi was studied in EMF-tieated water samples. Water samples were exposed to 9.575 GHz microwave modulated with square waves of different pulse repetition frequencies. The study indicates varying inhibitory effects of different modulation frequencies on spore germination of Alternaria alternata, A. tenuissima, Fusarium udum, Helminthosorium oryzae, H. turcicumand Ustilago cynodontis. The pulse repetition frequency-dependent variation in spore germination caused by irradiated water illustrates that water may have the capability to store EMF frequency effects. EMF-treated water might have caused the effect by either changing the activities of and/or deactivating the spore enzymes. © 1994 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.
Agro-morphological diversity in wild rice accessions of Eastern Indo-Gangetic region of India
(Bangladesh Botanical Society, 2014) S.K. Chouhan; A.K. Singh; Aparajita Singh; S.P. Singh; N.K. Singh; P.K. Singh
Thirty five wild rice germplasm accessions collected from natural habitat of Eastern Indo-Gangetic region of India were evaluated to estimate their extent of genetic variability, agro-morphological divergence and relationship among themselves for 14 traits. The accessions showed significant genotypic coefficient of variation for all traits analyzed. The accessions were clustered into six groups, the cluster III contained the highest 12 accessions, and clusters I and IV comprised 11 and 7 accessions, respectively; while cluster II and VI have two accessions each, and clusters V was monogenotypic. The maximum intra-cluster distance was observed in cluster VI followed by clusters IV and II while in inter-cluster distance was observed between clusters V and VI followed by clusters II and V indicates wider genetic diversity between germplasm accessions. High heritability coupled with high genetic advance as per cent of mean was found in the traits filled grains per panicle, total number of grains per panicle and grain yield per plant. The result suggested that these accessions are valuable resource and can be utilized for yield and yield traits besides disease and pest. Therefore, these accessions should be conserved to utilize in transgressive segregation breeding programme of cultivated indica rice.
Agro-techniques for baby corn production
(Springer Singapore, 2019) M.K. Singh; S.P. Singh; B. Singh
Baby corn (Zea mays L.) is a high-value crop, gaining popularity fast, and relatively recently introduced in India. Baby corn may be raised year-round, has short duration, and is fast growing and thus opens avenues for crop diversification. Baby corn is a suitable crop for cultivation under diverse agroclimatic conditions. The agro-techniques for baby corn are different from maize, viz., varieties, seed rate, plant density, detasseling, fertilizer management, and harvesting schedule. Higher plant densities with optimum geometry are essential to harness the yield potential. Intercropping with short-duration legumes and vegetables during winters gave profitable response. Removal of tassel with its emergence considerably enhances the yield of baby corn. Combined approach (soil application followed by foliar) in nitrogen management improves yield and quality of winter baby corn. Adoption of staggered planting will be helpful for continued supply for a longer period and in reducing the labor requirement during peak period. Standardization of the improved agro-techniques for diverse farming situations is required for wider popularization of the baby corn cultivation in India. © Springer Nature Singapore Pte Ltd. 2019.
Amphotericin B treatment for Indian visceral leishmaniasis: Response to 15 daily versus alternate-day infusions
(2007) Shyam Sundar; J. Chakravarty; V.K. Rai; N. Agrawal; S.P. Singh; V. Chauhan; Henry W. Murray
Background. For patients with Indian visceral leishmaniasis, amphotericin B deoxycholate is usually given as 15 alternate-day infusions of 1 mg/kg over 30 days (total dose, 15 mg/kg); daily treatment with 1 mg/kg for 20 days (total dose, 20 mg/kg) is also used. This study was done to address the unsettled therapeutic questions of administration schedule (alternate-day vs. daily administration) and dose (1 vs. 0.75 mg/kg) and to determine whether the duration of amphotericin B treatment in Bihar, India, can be shortened to 15 days. Methods. To compare alternate-day versus daily administration and 1-mg/kg versus 0.75-mg/kg doses and to determine whether the duration of treatment could be abbreviated, Indian subjects randomly received 15 infusions of 1 mg/kg (group A; 245 patients) or 0.75 mg/kg (group B; 244 patients) on alternate days or 1 mg/kg (group C; 500 patients) or 0.75 mg/kg (group D; 496 patients) daily. Noninferiority testing compared 6-month cure rates using a 5% margin. Results. Overall, 1439 of the 1485 subjects completed treatment and responded. Treatment interruptions (nephrotoxicity) but not infusion-associated reactions or study removals were more common with daily administration. Final cure rates at 6 months were similar: group A, 234 patients (96%; 95% confidence interval [CI], 92%-98%); group B, 225 patients (92%; 95% CI, 88%-95%); group C, 483 patients (97%; 95% CI, 95%-98%); and group D, 476 patients (96%; 95% CI, 94%-97%; P > .05). Conclusions. Provided that the serum creatinine level is repeated once, daily treatment with amphotericin B, 0.75 mg/kg for 15 days (total dose, 11.25 mg/kg), is efficient and effective for visceral leishmaniasis in India. Trial registration. ClinicalTrials.gov identifier: NCT00310505. © 2007 by the Infectious Diseases Society of America. All rights reserved.
An analytical study of a doubly clad compressed ellipse optical waveguide
(2014) S.P. Singh; R. Jatan; R. Janma; B.D. Singh; Vivek Singh; M.P.S. Rao
Using an analytical method based on boundary matching technique, the modal behavior and cutoff frequencies of a compressed ellipse doubly clad optical waveguide is studied. The proposed waveguide consists of a core region of higher refractive index with two cladding regions: one is inner cladding and the other is outer cladding. We take appropriate orthogonal coordinates for the proposed structure and impose the boundary conditions to obtain the characteristic equation. The effect of the width of inner cladding layer on the dispersion characteristic is observed. It is found that the width of inner cladding is able to tailor the dispersion characteristic and cutoff condition of the waveguide up to a certain limit. © 2013 Elsevier GmbH.
An electron gas model for the lattice dynamics of thallium and zirconium
(Società Italiana di Fisica, 1975) S.P. Singh; J.R. Maurya; S.S. Kushwaha
Metallic lattice is visualized as a series of point ions immersed in an electron gas. The total interaction with the metal is supposed to consist of ion-ion central interaction and ion-electron interaction. The former has been incorporated along the lines of Born-Karman and the latter has been accounted for by considering the ionic charge as smeared over the metal. The force corresponding to the strain developed within the Wigner-Seitz sphere is averaged over the whole sphere. The phonon dispersion relations along the symmetry direction and the (θ-T)-curve have been plotted for zirconium (Zr) and thallium (Tl) with force constants effective up to fourth neighbour only. The theoretical values are found to be closer to the experimental data. © 1975 Società Italiana di Fisica.
An Indian community-based epidemiological study of wounds.
(2004) N. Gupta; S.K. Gupta; V.K. Shukla; S.P. Singh
OBJECTIVE: To establish the prevalence of wounds in a community, with an emphasis on chronic lower extremity wounds, and to identify the various aetiological factors involved. METHOD: A cross-sectional study was conducted to screen the population of two nearby communities (one urban and one rural) in India for wounds. This involved conducting a door-to-door survey between July 2001 and February 2003. RESULTS: The prevalence of wounds in the population studied (n = 6917) was 15.03 per 1000.The prevalences of acute and chronic wounds were 10.55 and 4.48 per 1000 of the population respectively. CONCLUSION:The most common site for both acute and chronic wounds was the lower extremity. In contrast to Western studies, the most common aetiology for a chronic lower extremity wound was an untreated acute traumatic wound. This in turn highlights the need to establish community-based wound-care teams in India.
Analysis of a sheath helix in coaxially multi-layered dielectric environment
(IETE, 1995) S.K. Pathak; S.P. Singh; R.K. Jha
The EM power deposition in the biological tissue layers (bone/muscle/fat/skin) of rat's thigh/limb placed within a sheath helix in coaxially multilayered dielectric environment has been analyzed theoretically by both field and equivalent circuit approaches. For this, high frequency slow wave assumption has been made. Employing field analysis approach, dispersion relation is obtained by substituting field expressions (in different layers) into forty proper boundary conditions. To solve for the complex propagation constant, an iterative algorithm has been developed by applying Muller's procedure. The complex axial propagation constant, axial depth, and electromagnetic fields inside every tissue layer within each of the three wire helices of radii equal to 0.50, 0.60, and 0.70 cm and respective pitches 0.165, 0.197, and 0.231 cm, are then determined and patterns of specific absorption rate (SAR) at 2.45, 2.70, and 3.00 GHz are computed and presented. The results of an equivalent circuit analysis has also been reported. It is found that the dispersion relation in the absence of dielectric losses, obtained using this approach is identical with that of field analysis. The numerical values of phase and attenuation constants obtained using the two analysis approaches for each of three helices at 2.45, 2.70, and 3.00 GHz are in agreement with each other.
Analysis of H-plane sectoral dielectric horn antennas
(Publ by IEEE, 1993) T. Tiwari; S.P. Singh; A.R. Bayat; R.K. Jha; Banmali S. Rawat
The plane wave approach has been used to analyze the radiation from H-plane hollow sectoral dielectric horn antennas. Theoretical and experimental radiation patterns at x-band for 20°, 30°, and 40° flare angles, dielectric thickness of 0.30 cm and 0.44 cm and axial length of one γ have been obtained.