Cannanore, India
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Thomas N.,Nirmalagiri College | Jithin P.V.,Nirmalagiri College | Sudheesh V.D.,Nirmalagiri College | Sebastian V.,Nirmalagiri College
Ceramics International | Year: 2017

Magnesium substituted cobalt ferrite samples were prepared using solution combustion synthesis without any post-heat treatment. Structural characterization confirms the pure spinel phase with high crystallinity. The cation distribution of the samples was calculated using the value of lattice parameter obtained from Rietveld refinement. Hard to soft magnetic transition was observed as magnesium progressively replaces cobalt in spinel phase. Dielectric properties exhibit a behaviour which is similar to what has been reported for spinel ferrite family. This behaviour could be explained by a Maxwell–Wagner interfacial type polarization. © 2017 Elsevier Ltd and Techna Group S.r.l.


Rakesh K.E.,Nirmalagiri College | Babu A.T.,Nirmalagiri College | Antony R.,Nirmalagiri College
Asian Journal of Chemistry | Year: 2017

Modified chicken feather has been used as a low cost biosorbent for the studies of isotherm and kinetics of methylene blue dye adsorption from aqueous solution. Modified chicken feather was characterized by XRD and FTIR. Effects of pH, initial concentration of the dye, biosorbent dosage and contact time have been studied. Equilibrium studies showed that data fits better with Freundlich isotherm. The kinetics of adsorption has been best described by pseudo-first-order model. © 2017, Chemical Publishing Co. All rights reserved.


Sebastian S.,Nirmalagiri College | Ramakrishnan T.V.,SES College
Journal of Intelligent and Fuzzy Systems | Year: 2013

This paper introduces the concept of Atanassov intuitionistic fuzzy sets generating map (AIFSGM) on L-fuzzy spaces. AIFSGMs produce intuitionistic fuzzy sets from lattice valued fuzzy sets. © 2009 - IOS Press and the authors.


PubMed | Mangalore University, Nirmalagiri College, Indian Institute of Science and Flat L
Type: Journal Article | Journal: Zootaxa | Year: 2016

There has been much confusion around the identity of Hypselobarbus pulchellus, an endemic large barb of the Western Ghats. Recent works highlighted the fact that it is likely that two similar-looking species have been considered as H. pulchellus. A genetic analysis helps differentiate the two forms: viz., H. pulchellus and a new species, here described as H. bicolor sp. nov. Hypselobarbus bicolor can be distinguished from all other species of Hypselobarbus based on a combination of the following characters: two pairs of barbels, lateral line complete, with 34-36+1-2 pored scales, 6/1/3 scales in the transverse row; 11-12 predorsal scales; last simple dorsal ray weak, dorsal fin with 9 branched rays, gill rakers short and simple, 4-6+11-12 on first gill arch; proximal end of fifth ceratobranchial slightly curved, with 5+3+2 teeth; overall coloration dark grey with an ill-defined silver- or bronze-coloured band running along length of body, two scales high, on lateral-line scale-row and row above it; fins devoid of any markings; and small, closely-placed tubercles restricted to the tip of the snout in large males.


Schumann J.,Fritz Haber Institute | Eichelbaum M.,Fritz Haber Institute | Lunkenbein T.,Fritz Haber Institute | Thomas N.,Fritz Haber Institute | And 7 more authors.
ACS Catalysis | Year: 2015

The promoting effect of Al, Ga, and Mg on the support in Cu/ZnO catalysts for methanol synthesis has been investigated. Different unpromoted and promoted ZnO supports were synthesized and impregnated with Cu metal in a subsequent step. All materials, supports, and calcined and activated catalysts were characterized by various methods, including contactless (microwave) conductivity measurements under different gas atmospheres. Small amounts of promoters were found to exhibit a significant influence on the properties of the oxide support, concerning textural as well as electronic properties. We found correlations between the conductivity of the ZnO support and the activity of the catalyst in the reverse water-gas shift reaction (rWGS) as well as in methanol synthesis. In rWGS the activation energy and reaction order in H2 are decreased upon promotion of the ZnO support with the trivalent promoters Al3+ and Ga3+, indicating an electronic promotion. In methanol synthesis, results point to a structural promotion by Al3+ and Ga3+. A detrimental effect of Mg2+ doping was observed in both reactions. This effect is discussed in the context of the reducibility of ZnO under reaction conditions, which can be tuned by the promoter in different ways. The reducibility is seen as a critical property for the dynamic metal support interaction of the Cu/ZnO system. © 2015 American Chemical Society.


Raghavan R.,Kerala University of Fisheries and Ocean Studies | Philip S.,Nirmalagiri College | Ali A.,Kerala University of Fisheries and Ocean Studies | Katwate U.,Bombay Natural History Society BNHS | Dahanukar N.,Indian Institute of Science
Reviews in Fish Biology and Fisheries | Year: 2016

We summarize the research on Asian Sun catfish, Horabagrus brachysoma (Günther), an endemic and threatened freshwater catfish from Western Ghats of India, and provide a comprehensive review of its taxonomy, distribution, biology, population, conservation and aquaculture. Although described in 1864, the taxonomy of H. brachysoma, particularly its familial affinities, continues to be in flux. The species, originally described from the erstwhile ‘state of Cochin’ in present day Kerala State, India, has a current distribution ranging from southern Kerala (8°N) to southern Maharashtra (16°N), where they are found in lowland westward-flowing rivers, as well as natural freshwater lakes and backwaters. As a much relished food fish, H. brachysoma is exploited throughout its range, predominantly through an unmanaged artisanal fishery. Although there are no scientific estimates of either the status or trends in overall population of this endemic catfish, anecdotal evidence and fisher-knowledge suggests drastic declines of several local populations. The fishery for H. brachysoma in the Periyar and Achenkovil rivers in the State of Kerala has been documented to be unsustainable. As a result of an overall population decline of 35 % due to overharvest and habitat loss, H. brachysoma is assessed as ‘Vulnerable’ on the IUCN Red List of Threatened Species™. Primary research on various aspects of feeding, reproductive biology and demography has generated a wealth of information on the species, but this knowledge is yet to be utilized for the development and implementation of in situ conservation or management plans. In view of its high consumer demand, efficient biological and eco-physiological characteristics, as well as the availability of a captive breeding technology, H. brachysoma is considered an emerging species for small-scale aquaculture. Priorities for scientific research to address knowledge-gaps, as well as strategies for effective conservation of this threatened freshwater catfish are discussed. © 2016 Springer International Publishing Switzerland


Sudheesh V.D.,Mohanlal Sukhadia University | Nehra J.,Mohanlal Sukhadia University | Vinesh A.,Mohanlal Sukhadia University | Sebastian V.,Nirmalagiri College | And 5 more authors.
Materials Research Bulletin | Year: 2013

Nano powders of Ni0.5Zn0.5Fe2O4 have been synthesized by the self-combustion method at a relatively low temperature of 473 K under conditions of non-uniform and uniform heating. Rietveld fitting of X-ray diffractograms confirm the formation of the pure spinel phase in both samples. Transmission electron microscopy indicates that the sample prepared under non-uniform heating has a bimodal particle size distribution (average values 16 nm and 6 nm) while the one prepared under uniform heating has a very narrow particle size distribution (average size 4 nm). Low temperature, in-field Mössbauer spectroscopic studies clearly show surface spin contributions. The hyperfine fields and Curie temperature of the non-uniformly heated sample are in good agreement with those reported for the corresponding bulk samples. Despite having a very narrow particle size distribution, the uniformly heated sample has a large anisotropy distribution which is evident in the broad transition visible in the temperature dependent magnetization curve. It is also corroborated by the fact that the experimental magnetization curve at room temperature requires two Langevin functions for satisfactory reproduction. © 2012 Elsevier Ltd.


Raghavan R.,Outreach | Raghavan R.,Conservation Research Group CRG | Dahanukar N.,Outreach | Dahanukar N.,Indian Institute of Science | And 6 more authors.
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2015

Freshwater invertebrates receive relatively little publicity and conservation attention, in spite of their key role in aquatic food webs and ecosystem functioning. Decapod crustaceans such as caridean shrimps and gecarcinucid freshwater crabs comprise some of the most poorly known aquatic taxa, even in exceptional regions of freshwater biodiversity and endemism, such as the Western Ghats mountains of peninsular India. An analysis was carried out to understand distribution patterns and identify priority areas for decapod crustacean conservation in the Western Ghats region based on conservation status data retrieved from the IUCN Red List of Threatened Species. The Western Ghats region is home to 49 species and six sub-species of caridean shrimps (69% endemism) in four genera and two families, and 39 species of gecarcinucid crabs (92% endemism) in 14 genera. This diversity is probably an underestimate given the lack of biotic surveys and taxonomic research carried out on these groups. Three species (3%) of decapod crustaceans from the Western Ghats region are threatened with extinction, while more than half (51%; 48 species) are Data Deficient. The uncertainty regarding the true extinction risk of such a high number of Data Deficient species could hamper conservation efforts as well as policy development and implementation. Forty sites in the Western Ghats region are priorities for the conservation of decapod crustaceans, of which only seven lie within the existing network of protected areas. The specialized natural history and point endemic nature of many species of freshwater decapods, together with escalating human impacts on their aquatic ecosystems in the Western Ghats, makes conservation and management of these threatened and poorly-known species an immediate and urgent challenge. © 2014 John Wiley & Sons, Ltd.


Nabipour H.,Shahid Madani University of Azarbaijan | Hosaini Sadr M.,Shahid Madani University of Azarbaijan | Thomas N.,Nirmalagiri College
Journal of Experimental Nanoscience | Year: 2015

The intercalation of amoxicillin trihydrate (AMOX) into layered zinc hydroxide (LZH) has been achieved via ion-exchange method. The resulted nanocomposite (AMOX-LZH) has been thoroughly characterised by a number of techniques including powder X-ray diffraction (PXRD), FT-IR spectroscopy, TGA/DTG analysis and scanning electron microscopy (SEM). The PXRD results showed that the gallery height of LZH was expanded from 9.57 to 11.97 Å, indicating that the AMOX anions were successfully intercalated into the interlayer space of LZHs. The increased thermal stability of nanocomposite was confirmed by TGA/DTG analyses. Improved antibacterial activity and minimum inhibitory concentration of AMOX-LZH nanocomposite was evaluated against Gram-positive bacteria Staphylococcus aureus, Klebsiella pneumonia and Gram- negative Escherichia coli using the disk diffusion technique. The sustained release of amoxicillin drug from the AMOX-LZH nanocomposite was also verified. © 2015 Taylor & Francis.


Nabipour H.,Shahid Madani University of Azarbaijan | Sadr M.H.,Shahid Madani University of Azarbaijan | Thomas N.,Nirmalagiri College
New Journal of Chemistry | Year: 2016

Nalidixic acid (NA) was intercalated into zinc hydroxide nitrate (ZHN) by an ion exchange method. The resultant nanocomposite showed a basal spacing of 11.74 Å that corresponds to a pure phase, confirmed by powder X-ray diffraction (PXRD) studies. The arrangement of NA in the interlayer of ZHN was in a monolayer form. A FTIR spectroscopy study showed that the intercalation took place without any change in the structure of NA and the thermal analysis results showed that NA is stabilized in the interlayers by electrostatic interactions. Biocompatible NA-ZHN/chitosan nanocomposites were prepared by coating of the NA-ZHN nanocomposite with chitosan and the drug release behavior in vitro was studied. The antibacterial activities of the nanocomposite were tested against microorganisms. The results showed that the synthesized nanocomposites show good inhibition against two Gram-positive and Gram-negative species. NA-ZHN can prevent the growth of harmful bacteria more effectively than the NA drug. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016.

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