Reena Mary, A P; Narayanan, T N; Vijutha, Sunny; Sakthi Kumar, D; Yasuhiko, Yoshida; Joy, P A; Anantharaman, M R(Springer, 2010)
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Abstract:
Bio-compatible magnetic fluids having high
saturation magnetization find immense applications in
various biomedical fields. Aqueous ferrofluids of superparamagnetic
iron oxide nanoparticles with narrow size
distribution, high shelf life and good stability is realized by
controlled chemical co-precipitation process. The crystal
structure is verified by X-ray diffraction technique. Particle
sizes are evaluated by employing Transmission electron
microscopy. Room temperature and low-temperature magnetic
measurements were carried out with Superconducting
Quantum Interference Device. The fluid exhibits good
magnetic response even at very high dilution (6.28 mg/cc).
This is an advantage for biomedical applications, since only
a small amount of iron is to be metabolised by body organs.
Magnetic field induced transmission measurements carried
out at photon energy of diode laser (670 nm) exhibited
excellent linear dichroism. Based on the structural and
magnetic measurements, the power loss for the magnetic nanoparticles under study is evaluated over a range of
radiofrequencies.
Bejoy, Thomas; Prathapan, Sreedharan; Sugunan, Sankaran(Elsevier, May , 2005)
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Abstract:
The synthesis of dimethyl acetals of carbonyl compounds such as cyclohexanone, acetophenone, and benzophenone has successfully been carried out by the reaction between ketones and methanol using different solid acid catalysts. The strong influence of the textural properties of the catalysts such as acid amount and adsorption properties (surface area and pore volume) determine the catalytic activity. The molecular size of the reactants and products determine the acetalization ability of a particular ketone. The hydrophobicity of the various rare earth exchanged Mg–Y zeolites, K-10 montmorillonite clay, and cerium exchanged montmorillonite (which shows maximum activity) is more determinant than the number of active sites present on the catalyst. The optimum number of acidic sites as well as dehydrating ability of Ce3+-montmorillonite and K-10 montmorillonite clays and various rare earth exchanged Mg–Y zeolites seem to work well in shifting the equilibrium to the product side.
Anantharaman, M R; Suchand Sandeep, C S; Narayanan, T N; Shaijumon, M M; Ajayan, P M; Reji, Philip(IOP Publishing LTD, June 24, 2009)
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Abstract:
Magnetic heterostructures with carbon nanotubes having multiple functionalities are fascinating
materials which can be manipulated by means of an external magnetic field. In this paper we
report our investigations on the synthesis and optical limiting properties of pristine cobalt
nanotubes and high coercivity cobalt-in-carbon nanotubes (a new nanosystem where carbon
nanotubes are filled with cobalt nanotubes). A general mobility assisted growth mechanism for
the formation of one-dimensional nanostructures inside nanopores is verified in the case of
carbon nanotubes. The open-aperture z-scan technique is employed for the optical limiting
measurements in which nanosecond laser pulses at 532 nm have been used for optical
excitation. Compared to the benchmark pristine carbon nanotubes these materials show an
enhanced nonlinear optical absorption, and the nonlinear optical parameters calculated from the
data show that these materials are efficient optical limiters. To the best of our knowledge this is
the first report where the optical limiting properties of metal nanotubes are compared to those of
carbon nanotubes
Anantharaman, M R; Narayanan, T N; Shaijumon, M M; Ajayan, P M(American Chemical Society, July 3, 2008)
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Abstract:
Cobalt nanotubes (CoNTs) with very high longitudinal coercivity were prepared by electrodeposition of cobalt
acetate for the first time by using anodized alumina (AAO) template. They were then characterized with
X-ray diffraction (XRD), a field emission scanning electron microscope (FESEM), and a transmission electron
microscope (TEM). Formation of a highly ordered hexagonal cobalt phase is observed. Room temperature
SQUID (superconducting quantum interference device) magnetometer measurements indicate that the easy
axis of magnetization is parallel to the nanotube axis. These CoNTs exhibit very high longitudinal coercivity
of ∼820 Oe. A very high intertubular interaction resulting from magnetostatic dipolar interaction between
nanotubes is observed. Thick-walled nanotubes were also fabricated by using cobalt acetate tetrahydrate
precursors. A plausible mechanism for the formation of CoNTs based on mobility assisted growth is proposed.
The role of the hydration layer and the mobility of metal ions are elucidated in the case of the growth mechanism
of one-dimensional geometry
Anantharaman, M R; Shaijumon, M M; Ajayan, P M; Narayanan, T N(Springer, October 21, 2009)
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Abstract:
Hybrid magnetic nanostructures with high
coercivity have immense application potential in various
fields. Nickel (Ni) electrodeposited inside Cobalt (Co)
nanotubes (a new system named Ni @ Co nanorods) were
fabricated using a two-step potentiostatic electrodeposition
method. Ni @ Co nanorods were crystalline, and they have
an average diameter of 150 nm and length of *15 lm.
The X-ray diffraction studies revealed the existence of two
separate phases corresponding to Ni and Co. Ni @ Co
nanorods exhibited a very high longitudinal coercivity. The
general mobility-assisted growth mechanism proposed for
the growth of one-dimensional nanostructures inside nano
porous alumina during potentiostatic electrodeposition is
found to be valid in this case too
Muhammad, Abdul Jamal E; Joy, P A; Anantharaman, M R; Philip, Kurian(Elsevier, January , 2009)
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Abstract:
Nanocomposites based on natural rubber and nano-sized nickelwere synthesized by incorporating nickel
nanoparticles in a natural rubber matrix for various loadings of the filler. Structural, morphological, magnetic
and mechanical properties of the compositeswere evaluated along with a detailed study of dielectric
properties. Itwas found that nickel particleswere uniformly distributed in the matrix without agglomeration
resulting in a magnetic nanocomposite. The elastic properties showed an improvement with increase
in filler content but breaking stress and breaking strain were found to decrease. Dielectric permittivity
was found to decrease with increase in frequency, and found to increase with increase in nickel loading.
The decrease in permittivity with temperature is attributed to the high volume expansivity of rubber at
elevated temperatures. Dielectric loss of blank rubber as well as the composites was found to increase
with temperature.
Eby Thomas, Thachil; Unnikrishnan, K P; Benny Cherian, A; Jenish, Paul(Universal Research Publications, December , 2011)
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Abstract:
In this study, pendant epoxy functional poly dimethyl siloxanes were synthesized by the hydrosilylation reaction of pendant silyl hydride functional polydimethyl siloxane with allyl glycidyl ether. The hydrosilylation reaction was characterized by spectroscopic techniques. Samples of pendant epoxy functional poly dimethyl siloxanes and pendant silyl hydride functional polydimethyl siloxane were blended with commercial epoxy resin, diglycidyl ether of bis-phenol A, at various ratios using a polyamine as curing agent. The results show that the addition of functionalised poly dimethyl siloxanes increases the flexibility of the cross linked network and also the thermal stability and water resistance
Description:
Advances in Polymer Science and Technology: An International Journal 2011; 1 (2): 22-29
Stable, OH free zinc oxide (ZnO) nanoparticles were synthesized by hydrothermal method by varying the
growth temperature and concentration of the precursors. The formation of ZnO nanoparticles were confirmed by x-ray
diffraction (XRD), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) studies. The
average particle size have been found to be about 7-24 nm and the compositional analysis is done with inductively
coupled plasma atomic emission spectroscopy (ICP-AES). Diffuse reflectance spectroscopy (DRS) results shows that the
band gap of ZnO nanoparticles is blue shifted with decrease in particle size. Photoluminescence properties of ZnO
nanoparticles at room temperature were studied and the green photoluminescent emission from ZnO nanoparticles can
originate from the oxygen vacancy or ZnO interstitial related defects.
Prathapachandra Kurup, M R; Reena, T A(Springer, May 30, 2010)
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Abstract:
A new semicarbazone, HL has been synthesized
from quinoline-2-carboxaldehyde and N4-phenyl-3-
semicarbazide and structurally and spectrochemically
characterized. 1H NMR, 13C NMR, IR and electronic
spectra of the compound are studied. The existence of keto
form in the solid state is supported by the crystal structure
and IR data. The compound crystallizes into an orthorhombic
space group P212121. Intra and intermolecular
hydrogen bonding interactions facilitates unit cell packing
in the crystal lattice
Description:
J Chem Crystallogr (2010) 40:927–932
DOI 10.1007/s10870-010-9765-z
Prathapachandra Kurup, M R; Seena, E B; Leji, Latheef(Elsevier, November 1, 2008)
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Abstract:
A novel binuclear Ni(II) complex of salicylaldehyde 3-azacyclothiosemicarbazone (H2L) has been synthesized
and characterized by elemental analysis, IR and UV–Vis spectroscopy. The single crystal X-ray structure
of the complex shows that bridging occurs through thiolato sulfur and phenolic oxygen atoms.
Nickel centers in the complex have square planar and octahedral geometries
Prathapachandra Kurup, M R; Seena, E B; Mini, Kuriakose(Springer, February 9, 2010)
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Abstract:
Oxovanadium(IV/V) complexes of 2-hydroxyacetophenone-
3-hydroxy-2-naphthoylhydrazone (H2L)
have been synthesized and characterized. The complexes
were characterized by elemental analyses, IR, electronic
and EPR spectra. The oxovanadium(V) complex [VOL
(OCH3)] is crystallized in two polymorphic forms, denoted
by 1a and 1b, with space groups Pn21a and P 1, respectively.
Both have distorted square pyramidal structures.
Description:
Struct Chem (2010) 21:599–605
DOI 10.1007/s11224-010-9589-7
Binu, Varghese; Dr.Prathapachandra Kurup,M R(Cochin University of Science & Technology, February , 2009)
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Abstract:
The thesis is an introduction to our attempts to evaluate
the coordination behaviour of a few compounds of our interest.
Semicarbazones and their metal complexes have been an active area of
research during the past years because of the beneficial biological activities
of these substances. Tridentate NNO semicarbazone systems formed from
heterocyclic and aromatic carbonyl compounds and their transition metal
complexes are well-authenticated compounds in this field and their
synthesis and characterization are well desirable. Hence, we decided to
develop a research program aimed at the synthesis and characterization of
novel semicarbazones derived from 2-benzoylpyridine and 2-acetylpyridine
and their transition metal complexes. In addition to various physicochemical
methods of analysis, single crystal X—Ray diffraction studies were
also used for the characterization of the complexes.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Prathapachandra Kurup, M R; Binu, Varghese; Sithambaresan, M; Suja, Krishnan; Sheeja, S R; Eringathodi, Suresh(Elsevier, 2011)
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Abstract:
An interesting series of nine new copper(II) complexes [Cu2L2(OAc)2] H2O (1), [CuLNCS] ½H2O (2), [CuLNO3]
½H2O (3), [Cu(HL)Cl2] H2O (4), [Cu2(HL)2(SO4)2] 4H2O (5), [CuLClO4] ½H2O (6), [CuLBr] 2H2O (7),
[CuL2] H2O (8) and [CuLN3] CH3OH (9) of 2-benzoylpyridine-N(4)-phenyl semicarbazone (HL) have been
synthesized and physico-chemically characterized. The tridentate character of the semicarbazone is
inferred from IR spectra. Based on the EPR studies, spin Hamiltonian and bonding parameters have been
calculated. The g values, calculated for all the complexes in frozen DMF, indicate the presence of the
unpaired electron in the dx2 y2 orbital. The structure of the compound, [Cu2L2(OAc)2] (1a) has been
resolved using single crystal X-ray diffraction studies. The crystal structure revealed monoclinic space
group P21/n. The coordination geometry about the copper(II) in 1a is distorted square pyramidal with
one pyridine nitrogen atom, the imino nitrogen, enolate oxygen and acetate oxygen in the basal plane,
an acetate oxygen form adjacent moiety occupies the apical position, serving as a bridge to form a centrosymmetric
dimeric structure
Sreeja,P B; Prathapachandra Kurup, M R(Department of Applied Chemistry,Faculty of Science, 2004)
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Abstract:
This study concentrates the chemical properties of hydrazones due to its chelating capability and their pharmacological applications. Studies cover the preparation of different acid hydrazones and their structural studies and studies on their antimicrobial activity, synthesis and spectral characterization of different complexes of copper oxovanadium, manganese, nickel etc. Effect of incorporation of heterocyclic bases to the coordination sphere, change in the biological activity of acid hydrazones upon coordination, development of X-ray quality single crystals and its X-ray diffraction studies, studies on the redox behavior of the coordinated metal ions and correlation between the stereochemistry and biological activities.
Aleyamma, Saji Varghese; Dr. Kuruvila, Mathew(Cochin University of Science and Technology, May 19, 2005)
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Abstract:
This overall focus of the thesis involves the systematics and biology of fishes of the family hemiramphidae of cochin coast.India is one of the leading fish producing nations in the world with an average annual production of 6.1 million tonnes of fish and shell fish from capture and culture fisheries in 2001 (Ayyappan and Biradar, 2002).Fisheries play a very significant role in the Indian economy by providing employment to nearly 7 million people directly or indirectly, supplying rich protein food and earning valued foreign exchange.Fishes of the family Hemiramphidae are commonly called ‘half beaks‘.In India, studies on hemiramphids commenced with the work of Day (1878,1889) who recorded thirteen species of hemiramphids from the Indian waters.The study area, which is part of Cochin coast is located between Lat.9°28’ and 10° N and Long.76° 13’ and 76° 31 E. Lying parallel to it is an estuary which is commonly called the Cochin backwaters which has a total area of about 200 sq.miles.The study area is subjected to wide variations in salinity from place to place, season and surface to bottom.The Cochin coast and the adjacent back water system of Kerala has a rich and diversified fish fauna. The hemiramphid fishes constitute a minor fishery of this area.The study on the distribution and availability of hemiramphid fishes present in the Cochin coast shows that they evince different patterns of distribution.In the present study it is noticed that fecundity has high correlation with weight than length of the fish.Histological studies revealed that the spermatogenesis in both H. (H) limbatus and H.(H) xanthopterus, consists of spermatogonia, primary spermatocytes secondary, spermatocytes, spermatids and spermatozoa whereas in the oogenesis of both the species.biological study will be useful in implementation of proper measures of conservation and management so that further devastation of the hemiramphids of Cochin Coast can be controlled.
Description:
School of Industrial fisheries, Cochin University of Science and Technology
Sarita,G Bhat; Dr.Bright Singh,I S(Cochin University Of Science And Technology, May 4, 1998)
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Abstract:
Even though Bergey '5 Manual has been recognized globally as the guide to
bacterial systematics, it has to be emphasized that descriptions given to a large extent
are based on studies made with temperate isolates This leads one to conclude that
any attempt to identify the tropical isolates with identification keys and tables
generated from this information may lead to erroneous conclusions. And there is
every possibility of the existence of genotypic and phenotypic variants or even nev.
species in this part ofthe aquatic ecosystem. Applications ofa polythetic scheme of
classification based on the principles of Numerical Taxonomy opens up exciting
avenues for bringing to light, this possibility which otherwise would have been
masked by the unidirectional approach as in monothetic schemes.
Another added advantage of clustering a ‘natural’ bacterial population by
numerical taxonomy, is the ease by which genotypic characterization could be
performed on the clusters by selecting a representative from each cluster This helps
overcome the practical impossibility of analyzing all the isolates in a pani:'_lar
cluster. The genotypic characteizarion would either be mole °/o G-'rC. DNA-D.\_-X
hybridization, DNA-RNA hybridization or DNA fingerprinting. Considering the requirement creating a broad base in the understanding of the family Vibrionaceae associated with the larvae ofM rosenbergii, the present work was undertaken to channelize every new information generated for developing appropriate managerial measures to protect the larvae from vibriosis during the unusually prolonged larval phase.
Description:
School of Environmental Studies.
Cochin University of Science and Technology