Khurana P.,Kc College |
Khurana P.,Banasthali University |
Thatai S.,Banasthali University |
Thatai S.,Amity University |
And 3 more authors.
Microchemical Journal | Year: 2016
This study reports the synthesized core-shell bimetallic nanocomposites of silver and gold, respectively by varying the thickness of Au shell and studying its role in enhancing the Raman scattering of the molecule. The crystal violet (CV) was chosen as the target analyte molecule and the surface enhanced Raman scattering (SERS) enhancement of this molecule was studied as a function of Au shell thickness. The appropriate thickness of Au nanoshell, deposited on the Ag nanoparticles to obtain the maximum SERS enhancement, was identified and further increase in thickness of Au showed a decrease in intensity of the SERS signals. Among all the fabricated Ag@Au specimens ~30nm of Ag seed with 8nm of Au nanoshell showed the maximum enhancement of the SERS signals of CV. The close proximity of discontinuous Au shell acts as SERS hot spots by creating molecular level gap that accommodates the CV molecules responsible for the SERS enhancement up to the order of 1013 which is highly reproducible. © 2015.
Vyas C.K.,Sungkyunkwan University |
Joshirao P.M.,Sungkyunkwan University |
Bagla H.,Kc College |
Manchanda V.K.,Sungkyunkwan University
Journal of Radioanalytical and Nuclear Chemistry | Year: 2013
An attempt has been made in the present work to investigate the role of anion for the uptake of Am(III)/Eu(III)/U(VI) by extraction chromatography (EXC) resin incorporating tetra-n-octyl-3-oxapentanediamide, commonly referred to as tetra-octyl diglycolamide (TODGA). In contrast to the nitric acid, perchloric acid medium favors extraction of trivalent metal ions even at low acidity (pH 2) and is almost insensitive to the acidity up to 5 M. Exceptionally large distribution coefficients (105-106) in the wide range of perchlorate concentration (10-2-5 M) is quite unusual and is by far the largest reported in the literature for Am(III)/Eu(III). Thermodynamic data suggests the possibility of inner sphere/cation exchange mechanism involving TODGA aggregates at higher acidity but outer sphere/cation exchange mechanism at low acidity for Eu(III). There is a possibility of employing TODGA based EXC resin for the remediation of liquid waste (contaminated with long lived transuranics like 241/243Am and 245Cm) in the wide range of acidity. © 2013 Akadémiai Kiadó, Budapest, Hungary.
Sastry M.D.,Gemmological Institute of India |
Gaonkar M.P.,Gemmological Institute of India |
Nagar Y.C.,Physical Research Laboratory |
Mane S.N.,Gemmological Institute of India |
And 4 more authors.
Diamond and Related Materials | Year: 2011
We report the first optically stimulated luminescence (OSL; blue light stimulated luminescence (BLSL) and infrared light stimulated luminescence (IRSL)) results on colored diamonds and present experimental evidence that electron beam treatment (EBT) increases the radiation sensitivity of diamonds to a level that makes them suitable for low level radiation dosimetry. A suite of seven samples was examined. These comprise a white, three brown and three yellow diamond pieces. The FT-IR spectra of these diamonds revealed the nature and concentration of nitrogen impurity. The white diamond was kept as a control. The brown and yellow (with varied saturation) diamonds were irradiated by a 1.7 MeV electron beam. These turned blue/dark green; three of them were then heated in vacuum in the temperature range of 850-900 °C for two hours. Heating turned the irradiated diamonds to lemon yellow, pink, and purple colors. The irradiated and unheated blue samples were designated as 2C and 2D. The control sample, an un-irradiated white type Ia diamond, did not yield any significant IRSL/BLSL with doses up to 100 Gy. The BLSL/IRSL sensitivity of irradiated and heat treated diamonds was very poor, and depended on the heat cycle and hence were not pursued. Sample 2C exhibited significant BLSL and negligible IRSL sensitivity. Sample 2D gave an intense orange red emission under IR excitation as also responded to BLSL. The dose response of the BLSL signal in 2C suggested a minimum detectable dose of ~ 0.1 Gy and its use as a tissue equivalent dosimeter. Based on supporting experiments such as laser excited photoluminescence, we suggest that the BLSL process in 2C is primarily driven by carbon vacancies, which release a mobile hole when excited by GR2 band in the blue region. BLSL intensity exhibited a maximum around 285 °C. Given that TL glow peak also occurs near this temperature and that the nitrogen-interstitial carbon (N-Ci) complex also forms at this temperature (as reported in the literature), and it appears that the e-h recombination at sites with N-Ci complex could be involved in BLSL production. Laser excited photoluminescence (PL) at wavelengths 325, 514 and 785 nm and absorption spectra in UV-Visible range gave insights into the contrasting BLSL/IRSL responses of 2C and 2D. These differences were due to differences in nitrogen impurity complexes and the concentration of carbon vacancies produced by EBT in 2C and 2D. In 2D, the presence of Ni as NE8 center (four nitrogens coordinated to Ni) giving 800 nm emission on 785 nm excitation, appeared to suppress BLSL and sensitize IRSL in the orange window. © 2011 Elsevier B.V. All rights reserved.
Thite A.H.,Kc College |
Menon G.S.,Rk Talreja College
Pakistan Journal of Biological Sciences | Year: 2012
The effect of sewage water irrigation along with the N-fertilizers on NO 3 accumulation and on the in vivo NR assay in three leafy vegetable crops were studied. It was found that the NO 3 content in the leaves from the experimental sites were around two fold than the control and the NR enzyme activity was comparatively more in the control samples. The in vivo NRA with NaCl treatment increased at low level of NaCl where as with high level of NaCl, the enzyme activity decreased considerably. This is suggestive of the fact that NO 3 accumulation may be due to antagonistic effect of chloride ions. © 2012 Asian Network for Scientific Information.
Maiti M.,Saha Institute of Nuclear Physics |
Tiwari S.R.,Kc College |
Dubey N.B.,Kc College |
Bagla H.,Kc College |
Lahiri S.,Saha Institute of Nuclear Physics
Journal of Radioanalytical and Nuclear Chemistry | Year: 2013
We have measured 7Be activity in moss samples collected from in and around Mumbai, India. The use of heavily shielded Compton suppressor system is more efficient than the conventional gamma spectroscopic system for detection of 7Be. The 7Be accumulation capacities of mosses are more than other plant samples. Therefore monitoring of young moss samples by Compton suppressor system is an excellent tool for determination of atmospheric fallout of 7Be. A positive bias in the high altitude samples has been observed which might be due to any of the two reasons (i) higher cosmic ray flux in the high altitude or (ii) high pollution in the lower altitude area ultimately inhibits uptake of 7Be. © 2012 Akadémiai Kiadó, Budapest, Hungary.
Shastri J.P.,Kc College |
Rupani M.G.,Kc College |
Jain R.L.,Kc College
Journal of the Textile Institute | Year: 2012
Nanotechnology can be used in engineering-desired textile attributes, such as fabric softness and durability in fibres, yarns and fabrics. Nanocoating the surface of socks is one approach to the production of highly active surfaces with UV blocking, antimicrobial and self-cleaning properties. Synthesis of silver nanoparticles in this project was carried out chemically by wet reduction method (Ag-chem) and biologically by using neem (Azadirachta indica) leaves (Ag-neem). The formation of silver nanoparticles was monitored by UV-visible spectroscopy, which revealed the surface plasmon resonance peak at 420 nm for Ag-chem and 430 nm for Ag-neem, and transmission electron microscopy, which showed nanoparticles of various shapes and sizes (~5-50 nm). Quantification of the prepared silver nanoparticles was done by atomic absorption spectroscopy, which revealed 0.044 M Ag + and 0.042 M Ag + ions in Ag-chem and Ag-neem, respectively. Coating of the socks fabrics (nylon and cotton) was carried out by exposing these fabrics to the prepared nanoparticle solutions on a gyratory shaker overnight. Antimicrobial activity of the Ag-chem and Ag-neem was carried out by performing minimum inhibitory concentration (MIC) and disc diffusion test against Sarcina lutea, an odour-producing organism, Klebsiella pnuemoniae, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus and Candida albicans, organisms causing foot infections. P. aeruginosa and S. lutea were found to be most sensitive to either of the above preparations. Ag-chem was found to be more effective than Ag-neem. Nylon and cotton socks fabrics were coated with each of the above preparations. The antibacterial efficacy of the nanosilver-finished fabrics was checked by zone inhibition test, antibacterial test and wash fastness test. In both cases, coated nylon fabrics showed better antimicrobial activity than coated cotton fabrics. S. lutea and K. pneumoniae showed greater zones of inhibition than the other test organisms. Nylon fabric coated with Ag-chem and Ag-neem gave maximum reduction in viable count of all test organisms as compared to cotton fabrics. Higher reduction in the viable count of all test organisms was observed with Ag-chem-coated nylon fabrics. Thus, coating of the nylon socks fabric with silver nanoparticles can be used as an effective way to combat foot-borne pathogens and thereby reducing discomforts like foot odour, perspiration, complications due to diabetes, athlete's foot, etc. © 2012 Copyright The Textile Institute.
Dabholkar V.V.,Kc College |
Bhusari N.V.,Kc College
Indian Journal of Heterocyclic Chemistry | Year: 2011
2-Ethoxy carbonylcyclopentanone (1) has been brominated to yield 2-bromo-2-ethoxy carbonylcyclopentanone (2) which on further reaction with substituted thiosemicarbazones, thiocarbohydrazones, thiocarbamides and carbamides has furnished l-thia-3,4-diaza-5,7-dioxo-2-[(substituted benzyiidene)-amino]-spiro [4.5] dec-2-enes, (3a-e), 1-thia-3,4-diaza-5,7-dioxo- 2-[(substituted benzylidene)-hydrazino] spiro [4.5]dec-2-enes, (4a-e), 1-thia-3-aza-2-imino-4,6-dioxo-spiro(4.4] nonanes, (5a-f)and 1-oxa-3-aza-2-imino-4,6-dioxo-spiro [4.4] nonanes (6a-g) respectively The structures of the compounds have been elucidated on the basis of spectral analysis.
PubMed | Kc College
Type: Journal Article | Journal: Pakistan journal of biological sciences : PJBS | Year: 2012
The effect of sewage water irrigation along with the N-fertilizers on NO3 accumulation and on the in vivo NR assay in three leafy vegetable crops were studied. It was found that the NO3 content in the leaves from the experimental sites were around two fold than the control and the NR enzyme activity was comparatively more in the control samples. The in vivo NRA with NaCl treatment increased at low level of NaCl where as with high level of NaCl, the enzyme activity decreased considerably. This is suggestive of the fact that NO3 accumulation may be due to antagonistic effect of chloride ions.