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Antifungal Activity of Methanolic of Centella asiatica and Andrographis panicuiata
Singh, Pratibha,Singh, U. P.,Singh, J. S. 한국균학회 2000 韓國菌學會誌 Vol.28 No.4
The antifungal activity of methanolic extracts of Centella asiatica and Andrographis panicullata leaves was observed against fourteen fungi, viz., Alternaria alternata, A. brassicae, A. brassicicola, A. solani, A. tenuissima, Cercospora blumae, Curvularia lunata, C. penniseti, and Drechslera monocems, D. oryzae, D. turitica, Fusarium albizziae and F. udum. Different concentrations of the methanolic extract (1000, 2000, 3000, 5000, 7000, 10000ppm) were used. The effect of mixed leaf extract (1500 ppm of C. asiatica + 1500 ppm of A. paniculada) and its 1:2 ad 1:4 dilutions were also studied. The individual extracts of both the plants showed significant inhibitory effect on spore germination of all the fungi tested. F. udum, F. albizzae, D. oryzae, D. turtica, and D. monocems were particularly sensitive to these extracts. In general, the extract of C. asiatica showed a higher inhibitory effect in all concentrations against all the fungi as compared to A. paniculata, except for A. brassicae A. solani, D. oryzae, D. penniseti and Curvularia sp. The inhibitory effect of extracts increased when they were used in combination with or without dilutions against A. brassicicola, A. solani A. brassicae, A. alternata, A. tenussima, C blumae, C. lunata, C. penniseti and Curvularia species. Higher efficacy of active ingredient of these extracts under field condition is envisaged against plant pathogens.
Singh, J.,Lee, B.K. Academic Press 2016 Journal of environmental management Vol.170 No.-
<P>Phytoremediation is a highly efficient technique for the elimination of trace elements from contaminated soils through the shoots and roots of plants. This study was carried out to investigate the effects of nano titanium dioxide (TiO2) on Cd uptake by soybean plants. The objective of the present research was to examine the potential to improve the phytoextraction of Cd by the application of nano-TiO2 particles. The results showed that an addition of Cd to the soil significantly decreased plant growth and the biomass, pigment and protein contents. Increases in the proline content and malondialdehyde (MDA) indicate that Cd toxicity stresses the plants. Fourier transform infrared spectroscopy (FTIR) was used to determine variations in functional groups due to the Cd taken up into the shoot and root tissues of plants. An application of nano TiO2 particles restricts Cd toxicity by increasing the photosynthetic rate and growth parameters of the plants. The uptake of Cd was also increased from 128.5 to 507.6 mu g/plant with an increase in the nano TiO2 concentration from 100 to 300 mg/kg in the soil. The application of nano TiO2 significantly enhanced Cd uptake in the plants. The results of this study thus demonstrate that an application of nano-TiO2 can increase Cd uptake and minimize Cd stress in soybean plants. (C) 2016 Elsevier Ltd. All rights reserved.</P>
Singh, Vijay,Seshadri, M.,Singh, N.,Pathak, M.S.,Kumaran, R. Senthil,Choi, Yong-Keun,Singh, Pramod K.,Dhoble, S.J.,Srivastava, Anoop K. Elsevier 2016 Journal of luminescence Vol.176 No.-
<P><B>Abstract</B></P> <P>Combustion derived In<SUB>2</SUB>O<SUB>3</SUB>:Er<SUP>3+</SUP>, co-doped with Yb<SUP>3+</SUP>phosphor powders have been prepared. Powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray and Fourier transform infrared spectroscopy methods are used to characterize the prepared phosphor powders. The intensity parameters (<I>Ω<SUB>λ</SUB> </I>, <I>λ</I>=2, 4 and 6), radiative transition probabilities (<I>A<SUB>R</SUB> </I>), radiative lifetime (<I>τ<SUB>R</SUB> </I>) and branching ratios (<I>β</I>) of certain emission transition of Er<SUP>3+</SUP>ions for In<SUB>2</SUB>O<SUB>3</SUB>:Er<SUP>3+</SUP>and In<SUB>2</SUB>O<SUB>3</SUB>:Er<SUP>3+</SUP>/Yb<SUP>3+</SUP>phosphors have been estimated in the framework of the model given by Judd–Ofelt. Upon excitation at 978nm, upconversion luminescence properties of Er<SUP>3+</SUP>and Er<SUP>3+</SUP>/Yb<SUP>3+</SUP>doped In<SUB>2</SUB>O<SUB>3</SUB> phosphors are investigated. The results obtained from optical study confirm the existence of an effective Yb<SUP>3+</SUP>to Er<SUP>3+</SUP>energy transfer process and it also predict possible mechanisms to populate the <SUP>4</SUP>S<SUB>3/2</SUB> and <SUP>4</SUP>F<SUB>9/2</SUB> levels. The possible upconversion mechanisms are discussed for Er<SUP>3+</SUP>and Yb<SUP>3+</SUP>ions with energy level diagram.</P>
Singh, J.P.,Gautam, S.,Srivastava, R.C.,Asokan, K.,Kanjilal, D.,Chae, K.H. Academic Press 2015 Superlattices and microstructures Vol.86 No.-
Present work investigates the crossover from paramagnetism to superparamagnetism as a function of crystallite size in zinc ferrite nanoparticles using near edge X-ray absorption spectroscopy. Synthesized paramagnetic and superparamagnetic nanoparticles exhibit presence of Fe<SUP>2+</SUP> and Fe<SUP>3+</SUP> ions with dominant concentration of Fe<SUP>3+</SUP> ions. Fe L- and O K-edges spectra of paramagnetic nanoparticles consist of more intense spectral features compared to that of superparamagnetic nanoparticles. This reflects enhanced t<SUB>2g</SUB> and e<SUB>g</SUB> symmetry states of Fe-O hybridized states in paramagnetic nanoparticles induced by increased degree of crystallization.
Investigation of ultraviolet emitting Gd doped Sr<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub> phosphors
Singh, Vijay,Sivaramaiah, G.,Singh, N.,Pathak, M.S.,Rao, J.L.,Jirimali, H.D.,Natarajan, V. Elsevier 2018 Optik Vol.169 No.-
<P><B>Abstract</B></P> <P>This article deals with the ultraviolet (UV)-emitting gadolinium (Gd)-doped strontium magnesium disilicate (Sr<SUB>2</SUB>MgSi<SUB>2</SUB>O<SUB>7</SUB>) phosphors. A series of the Gd-doped Sr<SUB>2</SUB>MgSi<SUB>2</SUB>O<SUB>7</SUB> phosphors were prepared using a sol-gel method. The powders were well characterized using the X-ray powder diffraction (XRPD) and scanning electron microscope (SEM) techniques. The emission measurements upon a specific UV-light excitation (273 nm) showed the emission characteristics of the Gd<SUP>3+</SUP> that are due to the <SUP>6</SUP>P<SUB>J/2</SUB> → <SUP>8</SUP>S<SUB>7/2</SUB> transition. EPR spectra of the prepared samples indicated the presence of Gd<SUP>3+</SUP> ions in low symmetry sites in this sample.</P>
J. S. Dureja,Ranjit Singh,Talwinder Singh,Pargat Singh,Manu Dogra,Manpreet S. Bhatti 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.2 No.2
The benefits of cutting fluids in machining are well known, but their use is accompanied by health and environment hazards. Moreover, strict environmental regulations make the manufacturers to switch over to dry turning, which is not feasible during machining of sticky material like stainless steel and Inconel etc. Therefore, the use of minimal quantities of lubricant (MQL) can be regarded as an alternative solution and a step towards green machining. In the present investigation an attempt has been made to explore the potential of MQL turning of stainless steel with coated carbide cutting tool. Turning under MQL conditions has shown superior results (in terms of flank wear and machined surface roughness) over wet and dry turning. Signal to noise (S/N) ratio as per Taguchi design revealed speed and MQL as significant parameters for minimizing flank wear and surface roughness, whereas feed can be set within range. The optimum combination of parameters are cutting speed (58 m/min), feed rate (0.06 mm/rev.) and MQL flow rate (100 mL/h) for flank wear and cutting speed (23 m/min), feed rate (0.07 mm/rev.) and MQL flow rate (150 mL/h) for surface roughness. Taguchi optimized conditions were validated through multiple response optimization using desirability function.
Singh, B.,Kim, J.H.,Parkash, O.,Song, S.J. Ceramurgica ; Elsevier Science Ltd 2016 CERAMICS INTERNATIONAL Vol.42 No.2
The poor sintering-ability of tetravalent metal pyrophosphates MP<SUB>2</SUB>O<SUB>7</SUB> (M=Sn, Zr, Ce) has restricted their application as electrolyte in proton-conducting ceramic-electrolyte fuel cells (PCFCs). In this work, the effect of doping of MnO on the sinterability and ionic conductivity of MP<SUB>2</SUB>O<SUB>7</SUB> is analyzed. MnO-doped MP<SUB>2</SUB>O<SUB>7</SUB> is synthesized via a solid state reaction method. The phase composition and microstructure of MnO-doped MP<SUB>2</SUB>O<SUB>7</SUB> are studied with X-ray diffraction (XRD) and scanning electron microscopy (SEM) and the ionic conductivity of the sintered sample is measured by electrochemical impedance spectroscopy (EIS). It is observed that, compared to the undoped sintered samples, the porosity of the MnO-doped sintered samples is greatly decreased and the ionic conductivity is significantly improved.
Singh, N.,Sivaramaiah, G.,Rao, J.L.,Watanabe, S.,Rao, T.K. Gundu,Patel, R.V.,Singh, Vijay Elsevier 2017 Journal of luminescence Vol.188 No.-
<P><B>Abstract</B></P> <P>Gadolinium activated UV-emitting ZrO<SUB>2</SUB> phosphor has been prepared by combustion synthesis. The prepared phosphor was characterized using X-ray diffraction, scanning electron microscopy and energy dispersive X-ray techniques. The optical absorption spectrum in the 200−500nm region and excitation spectrum corresponding to the emission at 314nm for ZrO<SUB>2</SUB>:Gd<SUP>3+</SUP> phosphor has been recorded. Gd<SUP>3+</SUP> doped ZrO<SUB>2</SUB> displays electron spin resonance signals with effective g values at <I>g</I>≈1.9, 2.4 and 4.1. Low field signals are attributed to Gd<SUP>3+</SUP> ion located in distorted surroundings experiencing a relatively strong crystal field due to the proximity of charge compensator oxygen vacancies.</P>
Singh, Vijay,Sivaramaiah, G.,Singh, N.,Rao, J. L.,Dubey, Vikas,Singh, Pramod K. Springer-Verlag 2018 Journal of materials science. Materials in electro Vol.29 No.8
<P>Fe-doped CaAl12O19 was prepared via a simple combustion route. The formation of the as-prepared and post-heated combustion products was confirmed using an XRD analysis. The EPR spectrum of this sample exhibited a number of resonance signals. The paramagnetic centers have been quantified at different g factors in the range of 19.3-1.14. These resonance signals are attributed to pairs of Fe3+ ions. The resonance signal at a g value of similar to 4.2 is attributed to the axial-symmetry tetrahedral site. The resonance signal at a g value of similar to 2.0 is attributed to the presence of Fe3+ ions in an axial-symmetry octahedral site. The EPR parameters of the post-heated CaAl12O19:Fe3+ sample at room temperature and 110 K were calculated and compared.</P>
Singh, N.,Singh, V.,Sivaramaiah, G.,Rao, J.L.,Singh, P.K.,Pathak, M.S.,Dhoble, S.J.,Mohapatra, M. Elsevier [etc.] 2016 Journal of luminescence Vol.178 No.-
<P>Strong blue-green light emitting MgSrAl10O17:Eu2+,Mn2+ phosphor was synthesized by a low temperature initiated, self-propagating and gas producing combustion process in a very short time (< 5 min). Structural characterization of the luminescent material was studied with X-ray diffraction analysis and energy-dispersive X-ray analysis. The absorption spectrum exhibits bands due to Eu2+ and Mn3+ ions. The excitation spectrum shows a peak at 337 nm. Upon excitation at 337 nm, the emission spectrum exhibits an intense band centered at 462 nm due to transitions from the 4f(6)5d(1) to the 4f(7) configuration of the Eu2+ ions, whereas sharp peak at 513 nm attributed to T-4(1) -> (6)A(1) transition of Mn2+ ions. The X-band EPR spectra of MgSrAl10O17:Eu2+,Mn2+ showed the presence of Eu2+ and Mn2+ ions. (C) 2016 Elsevier B.V. All rights reserved.</P>