Anantharaman, M R; Soumya, Jose; Narayanan, T N; Senoy, Thomas; Al-Harthi, S H(IOP Publishing LTD, July 31, 2009)
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Abstract:
Two-dimensional electronic systems play a crucial role in modern electronics and offer a
multitude of opportunities to study the fundamental phenomena at low dimensional physics.
A quantum well heterostructure based on polyaniline (P) and iodine doped polyaniline (I) thin
films were fabricated using radio frequency plasma polymerization on indium tin oxide coated
glass plate. Scanning probe microscopy and scanning electron microscopy studies were
employed to study the morphology and roughness of the polymer thin films. Local electronic
density of states (LDOS) of the P–I–P heterostructures is probed using scanning tunnelling
spectroscopy (STS). A step like LDOS is observed in the P–I–P heterostructure and is
attributed to the quantum well confinement of electrons in the polymer heterostructure.
Sareena, John; Dr.Girish Kumar, K(Cochin University of Science and Technology, December , 2007)
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Abstract:
Potentiometric chemical sensors,an important class of electro-chemical sensors are widely used in pharmaceutical analysis because of its inherent advantages.The present study was aimed at fabrication of potentiometric sensors for the drugs mebendazole,pefloxacin,ambroxol,sildenafil citrate,dextro-methorphan and tetracycline.A total of 18 sensors have been developed for the determination of theses drugs.The major step in the fabrication of the sensor was the preparation of the ion association.Two types of sensors viz:PVC membrane sensor and carbon paste electode (CPE) were fabricated.The response characteristics of the different sensors fabricated were studied.Various response parameters studied include response time,selectivity and the effect of pH.The developed sensors were also employed for the determination of the drugs in pharmaceutical formulations and also for the recovery of the drug from urine samples.The selectivity studies reveal that the developed sensors are highly selective to the drug even in prescence of foreign ions.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Sindhu, Issac; Dr.Girish Kumar, K(Cochin University of Science & Technology, February , 2011)
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Abstract:
Voltammetric sensors are an important class of electrochemical sensors in which the analytical information is obtained from the measurement of current obtained as a result of electrochemical oxidation/reduction.This current is proportional to the concentration of the analyte.Chemically modified electrodes(CMEs) have great significance as important analytical tools for the electrochemical determination of pharmaceuticals.The modification of electrode results in efficient determination of electro-active biomolecules at very lower potential without its major interferences.The operation mechanism of CMEs depends on the properties of the modifier materials that are used to promote selectivity towards the target analytes.Modified electrodes can be prepared by deposition of various compounds such as organic compounds ,conducting polymers,metal oxides,etc. on the various electrode surfaces.The thesis presents the development ,electrochemical characterization and analytical application studies of eight voltammetric sensors developed for six drugs viz.,Ambroxol,Sulfamethoxazole,PAM Chloride, Lamivudine,Metronidazole and Nimesulide.The modification techniques adopted as part of the present work include Multiwalled Carbon Nanotube(MWCNT) based modification.Electropolymerisation and Gold Nanoparticle (AuNP) based modifications.
Description:
Dept.of Applied Chemistry,Cochin University of Science & Technology
Remalakshmy,Poduval; Girish Kumar,K(Department of applied chemistry, 2006)
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Abstract:
In this study Fabrication of Potentiometric sensors for the determination of certain metal ions, presents the synthesis and characterization of seven ionophores, their use in the fabrication of potentiometric sensors and the results and discussion of fourteen sensors developed for the determination of five transition metal ions. As part of the present investigations a total of fourteen potentiometric sensors have been developed and fabricated. A three fold approach has been taken in developing he sensors, PVC plasticized membrane sensor, carbon paste electrode and chemically modified carbon paste electrode. All the sensors are highly useful in the determination of metal ions such as manganese, nickel, copper, mercury and lead. A through analytical study has been carried out with respect to each other developed. Based on these studies, optimum conditions have been developed for the quantitative determinations of the selected metal ions using the sensors. Systematic application studies have also been carried out for all the developed sensors and the results revealed that the presently developed sensors are far superior than most of the sensors reported.
Beena, S; Dr.Girish Kumar, K(Cochin University of Science and Technology, May , 2010)
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Abstract:
In many fields such as earth science biology, environment and electronics, the knowledge about elemental distributions and chemical speciation is important. The determination of metal levels especially the toxic ones both in the environment and in biological materials are increasingly demanded by the society.Ion selective sensors have become one of the most effective ad powerful means for analytical scientists for the trace level monitoring of metal ions. The wide range of applications ,low material requirements and simplicity of analytical procedure have not only brought ion-selective electrodes in to the lime light of analytical chemistry,but have promoted their use as tools for physiologists,medical researchers,biologists,geologists,environmental protection specialists etc.Potentiometric ion-selective sensors have been developed for the determination of lanthanide ions such as La3+,Nd3+,Pr3+,Sm3+, and Gd3+.The sensors fabricated include both PVC membrane sensor and chemically modified carbon paste sensor. A set of 10 sensors have been developed. The response parameters of all the sensors have been studied and the sensors were applied as an indicator electrode in the potentiometric titration and for the determination of metal ions in real samples.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
The fabrication and analytical applications of two types of potentiometric
sensors for the determination of ketoconazole (KET) are described. The
sensors are based on the use of KET-molybdophosphoric acid (MPA) ion pair
as electroactive material. The fabricated sensors include both polymer membrane
and carbon paste electrodes. Both sensors showed a linear, stable and near
Nernstian slope of 57.8mV=decade and 55.2mV=decade for PVC membrane
and carbon paste sensors respectively over a relatively wide range of KET concentration
(1×10-2-5×10-5 and 1×10-2-1×10-6). The sensors showed a fast
response time of <30 sec and <45 sec. A useful pH range of 3–6 was obtained
for both types of sensors. A detection limit of 2.96 10 5M was obtained for
PVC membrane sensor and 6.91 10 6M was obtained for carbon paste sensor.
The proposed sensors proved to have a good selectivity for KET with respect to a
large number of ions. The proposed sensors were successfully applied for the
determination of KET in pharmaceutical formulations. The results obtained
are in good agreement with the values obtained by the standard method.
Sunitha, Sabastin; Dr. M. Kailasnath(Cochin University of Science and Technology, June 12, 2015)
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Abstract:
Polymer Optical Fibers have occupied historically a place for large core flexible fibers operating in short distances. In addition to their practical passive application in short-haul communication they constitute a potential research field as active devices with organic dopants. Organic dyes are preferred as dopants over organic semiconductors due to their higher optical cross section. Thus organic dyes as gain media in a polymer fiber is used to develop efficient and narrow laser sources with a tunability throughout the visible region or optical amplifier with high gain. Dyes incorporated in fiber form has added advantage over other solid state forms such as films since the pump power required to excite the molecules in the core of the fiber is less thereby utilising the pump power effectively. In 1987, Muto et.al investigated a dye doped step index polymer fiber laser. Afterwards, numerous researches have been carried out in this area demonstrating laser emission from step index, graded index and hollow optical fibers incorporating various dyes. Among various dyes, Rhodamine6G is the most widely and commonly used laser dye for the last four decades. Rhodamine6G has many desirable optical properties which make it preferable over other organic dyes such as Coumarin, Nile Blue, Curcumin etc. The research focus on the implementation of efficient fiber lasers and amplifiers for short fiber distances. Developing efficient plastic lasers with electrical pumping can be a new proposal in this field which demands lowest possible threshold pump energy of the gain medium in the cavity as an important parameter. One way of improving the efficiency of the lasers, through low threshold pump energy, is by modifying the gain of the amplifiers in the resonator/cavity. Success in the field of Radiative Decay Engineering can pave way to this problem. Laser gain media consisting of dye-nanoparticle composites can improve the efficiency by lowering the lasing threshold and enhancing the photostability. The electric field confined near the surface of metal nanoparticles due to Localized Surface Plasmon Resonance can be very effective for the excitation of active centers to impart high optical gain for lasing. Since the Surface Plasmon Resonance of nanoparticles of gold and silver lies in the visible range, it can affect the spectral emission characteristics of organic dyes such as Rhodamine6G through plasmon field generated by the particles. The change in emission of the dye placed near metal nanoparticles depend on plasmon field strength which in turn depends on the type of metal, size of nanoparticle, surface modification of the particle and the wavelength of incident light. Progress in fabrication of different types of nanostructures lead to the advent of nanospheres, nanoalloys, core-shell and nanowires to name a few. The thesis deals with the fabrication and characterisation of polymer optical fibers with various metallic and bimetallic nanostructures incorporated in the gain media for efficient fiber lasers with low threshold and improved photostability.
In this paper we address the problem of face
detection and recognition of grey scale frontal view images. We
propose a face recognition system based on probabilistic neural
networks (PNN) architecture. The system is implemented using
voronoi/ delaunay tessellations and template matching. Images
are segmented successfully into homogeneous regions by virtue
of voronoi diagram properties. Face verification is achieved
using matching scores computed by correlating edge gradients
of reference images. The advantage of classification using PNN
models is its short training time. The correlation based
template matching guarantees good classification results
Description:
Nature & Biologically Inspired Computing, 2009. NaBIC 2009. World Congress on
n this paper we address the problem of face
detection and recognition of grey scale frontal view images. We
propose a face recognition system based on probabilistic neural
networks (PNN) architecture. The system is implemented using
voronoi/ delaunay tessellations and template matching. Images
are segmented successfully into homogeneous regions by virtue
of voronoi diagram properties. Face verification is achieved
using matching scores computed by correlating edge gradients
of reference images. The advantage of classification using PNN
models is its short training time. The correlation based
template matching guarantees good classification results.
A series of novel naphthyridine derivatives 3
and 4 was prepared from substituted pyridine 2 and ketones
using ZnCl2 as catalyst under microwave irradiation conditions.
All the compounds were evaluated for AChE
inhibitory activity and promising compounds 3d, 3e, 4b,
and 4g was identified. Representative compounds 3d and
3e were found to show insignificant THLE-2 liver cell
viability/toxicity. The binding mode between X-ray crystal
structure of human AChE and compounds was studied
using molecular docking method and fitness scores were
found to be in good correlation with the activity data.
Description:
Med Chem Res (2012) 21:1785–1795
DOI 10.1007/s00044-011-9695-0
A simple and facile strategy for the synthesis of highly substituted
imidazoles has been developed by multi-component condensation of 1,2-diketone,
aldehyde, amine, and ammonium acetate in presence of tetrabutyl ammonium
bromide as catalyst
Description:
Res Chem Intermed (2012) 38:359–365
DOI 10.1007/s11164-011-0352-5