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Search Results: 1 - 10 of 401646 matches for " M. Behera "
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Inquiring the mechanism of formation, encapsulation, and stabilization of gold nanoparticles by poly(vinyl pyrrolidone) molecules in 1-butanol
M. Behera,S. Ram
Applied Nanoscience , 2013, DOI: 10.1007/s13204-013-0198-9
Abstract: We present a plausible mechanism of formation, encapsulation, and stabilization of gold nanoparticles (GNPs) in presence of poly(vinyl pyrrolidone) (PVP) in 1-butanol in support of UV–visible, Raman, Fourier transform infrared spectroscopy (FTIR), zetapotential, X-ray photoelectron spectrum (XPS), and transmission electron microscopy. A surface plasmon resonance band at 533 nm in the UV–visible spectrum reveals formation of ~20 nm spherical GNPs in the non-hydrocolloid. In the FTIR spectrum, selective enhancement in the intensity of C–H stretching and red-shift in the C=O band suggests that PVP encapsulate GNP by an interaction between PVP and GNP that occurs via O-atom of pyrrolidone ring. Raman and XPS spectrum well supports the findings of FTIR spectrum. Zeta potential of 15.22 mV at 7.5 pH found in PVP-capped GNP strongly recommends the role of electrosteric effect towards the observed colloidal stability. Microscopic image demonstrates a thin coating of amorphous PVP layer around GNPs in a core–shell structure. Probing the mechanism of formation, encapsulation, and stabilization of GNP could provide essential information for development of bimetallic NPs for catalytic applications.
Synthesis and characterization of core–shell gold nanoparticles with poly(vinyl pyrrolidone) from a new precursor salt
M. Behera,S. Ram
Applied Nanoscience , 2013, DOI: 10.1007/s13204-012-0076-x
Abstract: In this article, we report a facile one-step chemical synthesis of gold (Au) nanoparticles (GNPs) from a new precursor salt i.e., gold hydroxide in the presence of poly(vinyl pyrrolidone) (PVP) polymer. The non-aqueous dispersion of GNPs was comprehensively characterized by UV–Visible, FTIR, zeta potential, and transmission electron microscope (TEM). A strong surface plasmon resonance band at 529 nm in the UV–Visible spectrum confirms the formation of GNPs in the Au colloid. The FTIR spectroscopic results showed that PVP molecules get chemisorbed onto the surface of GNP via O-atom of carbonyl group. A negative zeta potential of ( )16 mV reveals accumulation of nonbonding electrons of O-atom of carbonyl group of PVP molecules on the nanosurface of GNP. TEM images demonstrate a core–shell nanostructure with an Au-crystalline core covered by a thin amorphous PVP-shell. PVP-capped GNPs could be a potential candidate for bio-sensing, catalysis, and other applications.
Intense quenching of fluorescence intensity of poly(vinyl pyrrolidone) molecules in presence of gold nanoparticles
M. Behera,S. Ram
Applied Nanoscience , 2013, DOI: 10.1007/s13204-012-0159-8
Abstract: We study the quenching of fluorescence intensity of 40 g/L poly(vinyl pyrrolidone) PVP molecules by varying the content of gold nanoparticles (GNPs) from 1 to 5 μM in 1-butanol. A profound exponential decay of the emission band intensity in the π ← nπ* band of the PVP molecules at ~392 nm upon gradual addition of the GNPs demonstrates an existence of an excited state interaction of NPs with the PVP molecules in a gold colloid in 1-butanol. Such quenching is caused by the non-bonding electron transfer from the O-atom of carbonyl group of the PVP molecules to the surface of the GNP. X-ray photoemission spectroscopy (XPS) study corroborates the spectroscopic results. A linear Stern–Volmer plot with a quenching constant of 2.23 × 106 M 1 reveals dynamic quenching in a non-aqueous NF. A mechanism of fluorescence quenching was proposed in support of XPS and images taken from hybrid nanostructure using transmission electron microscope. Study on quenching of fluorescence intensity of PVP fluorophore in the presence of GNPs is useful for optoelectronic devices and biosensors.
Synthesis, Characterization, and Biological Activity of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) Complexes of N-Thiophenoyl-N′-Phenylthiocarbohydrazide
M. Yadav,Debasis Behera
Journal of Chemistry , 2013, DOI: 10.1155/2013/721397
Abstract:
Gentiana kurroo Royle – A critically endangered bitter herb
M.C. BEHERA,R. RAINA
International Journal of Medicinal and Aromatic Plants , 2012,
Abstract: Gentiana kurroo Royle is a critically endangered bitter drug plant of western and northwestern Himalaya. The secondary plant metabolites present in the root and rhizome of this plant are valued as bitter tonic, antiperiodic, expectorant, antibilious, astringent, stomachic, anthelmintic, blood purifier, carminative, antipsychotic, anti-inflammatory, anti-bacterial and sedative. It is also medicated for curing skin diseases, leucoderma, leprosy, bronchial asthma, dyspepsia, flatulence, colic, anorexia, helminthiosis, inflammations, amenorrhea, dysmenorrheal, strangury, hemorrhoids, constipation and urinary infections. The drug plant is heavily extracted for root and rhizome. Because of restricted distribution and widespread extraction from its natural habitats coupled with nil cultivation, this species is in high risk category as far as its survival is concerned. The paper presents a comprehensive review on its morphophenology, ethnopharmacy, regeneration techniques and phytochemistry in a lieu to assist further research in chemical screening for elite genotype, developing agrotechniques of cultivation, varietal development and byproduct extraction and thereby protecting the miracle plant from extinction.
Inhibition Effect of Substituted Thiadiazoles on Corrosion Activity of N80 Steel in HCl Solution
M. Yadav,Sumit Kumar,Debasis Behera
Journal of Metallurgy , 2013, DOI: 10.1155/2013/256403
Abstract: The inhibition effect of some prepared compounds, namely, thiadiazole derivatives, on N80 steel corrosion in 15% HCl solutions has been studied by using the weight loss, electrochemical polarization, and electrochemical impedance spectroscopy techniques. It was found that the inhibition efficiency of the thiadiazole derivatives, namely, 2-amino-5-(4-methoxyphenyl)-1,3,4-thiazole (AMPT), 2-amino-5-phenyl-1,3,4-thiazole (APT), and 2-amino-5-(4-chlorophenyl)-1,3,4-thiazole (ACPT), increases with the increase in concentration. Inhibition efficiency follows the order AMPT > APT > ACPT. The effect of temperature on the corrosion was investigated by the weight loss method, and some thermodynamic parameters were calculated. The inhibitive action may be attributed to the adsorption of inhibitor molecules on the active sites of the metal surface following Langmuir adsorption isotherm. Polarization measurements indicated that thiadiazole derivatives act as mixed-type corrosion inhibitor. The adsorption of thiadiazole derivatives on N80 surface exposed to inhibitor-containing solutions was confirmed using SEM and FT-IR spectra. 1. Introduction N80 carbon steel has been generally used as the main construction material for down hole tubular, flow lines, and transmission pipelines in petroleum industry. In most industrial processes, acidic solutions are commonly used for pickling, industrial acid cleaning, acid descaling, oil well acidifying, and so forth [1–5]. It is commonly noticed that 15–28% of hydrochloric acid is used for the acidization of petroleum oil wells [6, 7]. Because of their aggressiveness, iron and its alloys get corrodes during these acidic applications particularly with the use of hydrochloric acid and sulphuric acid, which results in terrible waste of both resources and money [8]. Addition of inhibitor remains the necessary procedure to secure the metal against acid attack. Therefore, corrosion inhibitors for HCl solutions have attracted more attention. Most of the well-known corrosion inhibitors are organic compounds containing polar groups having nitrogen, sulphur, and/or oxygen atoms and heterocyclic compounds with polar functional groups and conjugated double bonds [9, 10]. These compounds can adsorb on the metal surface and partially blocking the active sites on the surface, thereby reducing the corrosion rate. Among different nitrogen- and sulphur-containing compounds, thiosemicarbazide has been reported to be a potential inhibitor for different metals [11, 12]. Most of the investigation is related to the application of common inhibitors
Computational Analysis of POL Gene of Human Immunodeficiency Virus Type 1 (HIV-1)
Pabitra M. BEHERA,Bijay K. SETHI,Kambaska K. BEHERA,Debashrita PANI
Notulae Botanicae Horti Agrobotanici Cluj-Napoca , 2009,
Abstract: AIDS results from an infection with HIV-1 virus. It is a class of retrovirus whose genome contains the genes for reverse transcriptase. The gene that codes for reverse transcriptase in HIV-1 is the POL gene. POL genes are found in many retroviruses, including a number that are harbored by human populations. In this paper POL genes of HIV-1 virus were studied using bioinformatics tools. It was observed that there exists a close resemblance among various strains endemic in Africa, China and India. In addition, they express a wide range of functional proteins after infection.
Stratigraphic Control of Petrography and Chemical Composition of the Lower Gondwana Coals, Ib-Valley Coalfield, Odisha, India  [PDF]
Alokranjan Senapaty, P. Behera
Journal of Geoscience and Environment Protection (GEP) , 2015, DOI: 10.4236/gep.2015.34007
Abstract: The Ib-valley coalfield of Odisha, India contains five coal seams viz. Ib-seam at the bottom overlain successively by Rampur seam, Lajkura seam, Parkhani seam and Belpahar seam. Twenty one representative samples were collected from three major seams (Ib, Rampur and Lajkura) and their petrography and chemical studies were carried out. Samples were not collected from the Parkhani and Belpahar seams as these are very small seams exposed locally having no regional correlation. The macroscopic study shows the dominance of durain which imparts a dull appearance to these coals. The maceral analysis reveals that vitrinite percentage varies from 4.5% to 80.2%, the exinite from 3.30% to 22.2% and the inertinite from 12.5% to 92.2% in different samples of the Ib valley coalfield. The very high proportion of inertinite suggests a shallower water deposition of plant materials followed by prolonged period of exposure and repeated cycle of weathering. The proximate analysis results show that the top Lajkura seam is comparatively lower in rank than the underlying Ib and the Rampur seam. The ultimate analysis exhibites that the percentage of variation in C is found from 77.88 to 85.79, H from 4, 4 to 5.91 and O from 7.26 to 15.3. H/C and O/C ratio including C.V. in this coalfield showing distinct variations from the bottom to top seam. The analyses results indicate that the petrographic and chemical characters of the ib valley coals are stratigraphically controlled.
Synthesis, Analgesic, Anti-inflammatory and Antimicrobial Activities of Some Novel Pyrazoline Derivatives
SK Sahu, M Banerjee, A Samantray, C Behera, MA Azam
Tropical Journal of Pharmaceutical Research , 2008,
Abstract: Purpose: Microbial infections often produce pain and inflammation. Chemotherapeutic, analgesic and anti-inflammatory drugs are prescribed simultaneously in normal practice. The compound possessing all three activities is not common.The purpose of the present study was to examine whether molecular modification might result in detection of new potential antirheumatic drugs having antimicrobial activities. Method: A series of novel 4-(5′-substituted aryl-4′, 5′-dihydropyrazole-3′-yl-amino) phenols 2a-f have been synthesized by treating substituted aryl-N-chalconyl amino phenols 1a-f with hydrazine hydrate. The starting materials were synthesized from p-aminoacetophenone. Their structures were confirmed by IR, 1H NMR spectral data. The synthesized compounds were investigated for analgesic, ant-inflammatory and antimicrobial activities. Result: The data reported in Tables 2, 3 & 4 shows that effect of variation in chemical structure on activity was rather unpredictable. Seldom did a particular structural modification lead to uniform alteration in activity in all tests. The substitution which appeared to be most important for high order of activity in the greatest number of test was the p-choloroaryl group. The introduction of p-nitro and p-hydroxy group in aryl moiety of the pyrazole analogs 2c and 2e produce compounds with potent analgesic, anti-inflamatory and, in a few cases, antimicrobial properties. Conclusion: The observed increase in analgesic, anti-inflammatory and antimicrobial activities are attributed to the presence of 4-NO2, 2-OH and 4-Cl in phenyl ring at 5-position of pyrazoline ring of synthesized compounds. In some cases their activities are equal or more potent than the standard drugs.
Becker′s nevus with ipsilateral breast hypoplasia
Sirka C,Puhan M,Behera S,Mohanty P
Indian Journal of Dermatology, Venereology and Leprology , 2009,
Abstract:
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