Thalassery, India
Thalassery, India

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Antony J.V.,Cochin University of Science and Technology | Antony J.V.,Government Brennen College | Chandran P.,Cochin University of Science and Technology | Kurian P.,Cochin University of Science and Technology | And 2 more authors.
Journal of Physical Chemistry C | Year: 2015

A simple aqueous method has been used for the direct synthesis of water-soluble sulfonated polystyrene (SPS) encapsulated CdS quantum dots (QDs). The aqueous solution of the QDs, stabilized by two SPSs of different sulfonation level, shows a blue shift in ultraviolet-visible (UV-vis) absorption and band edge emission. High resolution transmission electron microscope (HR-TEM) establishes the presence of quantum confined CdS particles. The sulfonation level of SPS influences the size of QDs and strongly affects the photoluminescence (PL). The CdS QDs passivated by SPS with less sulfonation level exhibit only band edge emission (463 nm), while QDs in aqueous solution of SPS with high sulfonic acid content emits predominantly defect state emission (610 nm) against the band edge emission (463 nm). The PL of the SPS-CdS nanocomposites demonstrates an interesting variation in emission spectra and quantum yield via the change in sulfonation level, the change in pH and on keeping in aqueous solution. In addition, the z-scan measurements show negative nonlinear refraction coefficient, indicating self-defocusing phenomena. The absolute value of the third order nonlinear refractive index and nonlinear absorption are decided by the CdS QDs surface chemistry. © 2015 American Chemical Society.


Antony J.V.,Cochin University of Science and Technology | Antony J.V.,Government Brennen College | Kurian P.,Cochin University of Science and Technology | Vadakkedathu N.P.N.,Cochin University of Science and Technology | Kochimoolayil G.E.,Cochin University of Science and Technology
Industrial and Engineering Chemistry Research | Year: 2014

A simple, direct method for generating a nanohybrid of CdS quantum dots (QDs) in functionalized waste polymer shows good optical properties combined with photocatalytic activities. Homogeneous sulfonation of expanded polystyrene waste (EPS) forms partially sulfonated polystyrene (PSS). Hydrogelation of the PSS facilitates the attachment of CdS QDs through sulfonic acid groups by ion-exchange mechanism, followed by trapping within the polymer network, ultimately generating an organic/inoganic nanohybrid. X-ray diffraction verifies the existence of the CdS nanocrystals and defines their cubic crystalline structure and crystallite size. High resolution transmission electron microscopy shows the formation of QDs in the nanohybrid. A blue shift in ultraviolet-visible absorption and photoluminescence confirm the QDs formation. The polymer chains effectively passivate the surface of CdS nanocrystals that exhibit exciton emission (455-471 nm) with less surface defect state emission (540 nm). In addition, the photocatalytic activity of the composite in degrading an organic dye is demonstrated. © 2014 American Chemical Society.


Nishanth T.,Sree Krishna College Guruvayur | Praseed K.M.,Sir Syed College | Satheesh Kumar M.K.,Government Brennen College | Valsaraj K.T.,Louisiana State University
Aerosol and Air Quality Research | Year: 2014

This paper presents the results of measurements of the surface ozone (O3), oxides of nitrogen (NOx), methane (CH4) and total non-methane hydrocarbons (TNMHCs) in a rural coastal location at Kannur (11.9°N, 75.4°E, 5 m asl), India from November 2009 to December 2011. The diurnal cycle for surface O3 had a peak in the afternoon and declined during nighttime. The maximum and minimum mixing ratio of surface O3 was observed in winter and monsoon seasons respectively. NOx concentration was high during mid-night to early morning and low during noontime. The diurnal variations of mixing ratios for NOx and O3 were anti-correlated. Monthly average maximum (2.26 ± 0.44 ppmv) and minimum (0.43 ± 0.19 ppmv) CH4 concentrations were observed in December and August respectively. The diurnal variations of CH4 were similar to that of NOx. A CH4 buildup was observed during early morning hours throughout the observational period. On an annual basis, the maximum, minimum and average total NMHCs were (25.45 ± 6.58 ppbv), (13.84 ± 4.31 ppbv), and (19.23 ± 5.56 ppbv) respectively at the observational site. Analysis of O3, NO, NO2, CH4 and NMHC have been carried out and the correlation between O3 and its precursors is discussed detailed. Further, the diurnal variation of O3 over a free tropospheric region at Ooty, a hill station lying in the Western Ghats region of south India on clear sky days in February 2011 is also reported for a comparison. © Taiwan Association for Aerosol Research.


Nishanth T.,Kannur University | Nishanth T.,Government Brennen College | Satheesh Kumar M.K.,Kannur University | Satheesh Kumar M.K.,Government Brennen College | Valsaraj K.T.,Louisiana State University
Journal of Atmospheric Chemistry | Year: 2012

Continuous measurements of surface ozone (O3), NOx (NO + NO 2) and meteorological parameters have been made in Kannur (11.9 °N, 75.4 °E, 5 m asl), India from November 2009 to October 2010. It was observed that O3 and NOx showed distinct diurnal and seasonal variabilities at this site. The annual average diurnal profile of O3 showed a peak of (30.3±10.4) ppbv in the late afternoon and a minimum of (3.2±0.7) ppbv in the early morning. The maximum value of O3 mixing ratio was observed in winter (44±3.1) ppbv and minimum during monsoon (18.46±3.5) ppbv. The rate of production of O3 was found to be higher in December (10.1 ppbv/h) and lower in July (1.8 ppbv/h) during the time interval 0800-1000 h. A correlation coefficient of 0.52 for the relationship between O3 and [NO2]/[NO] reveals the role of NO2 photolysis that generates O3 at this site. The correlation between O3 and meteorological parameters indicate the influence of seasonal changes on O3 production. Investigations were further extended to explore the week day weekend variations in O3 mixing ratio at an urban site reveals the enhancement of O3. The variations of O3 mixing ratio with seasonal air mass flows were elucidated with the aid of backward air trajectories. This study also indicates how vapor phase organic species present in the ambient air at this location may influence the complex chemistry involving (VOCs) that enhances the production of O3 at this location. © Springer Science+Business Media B.V. 2012.


Nishanth T.,Sree Krishna College Guruvayur | Praseed K.M.,Sir Syed College | Kumar M.K.S.,Government Brennen College | Valsaraj K.T.,Louisiana State University
Atmospheric Research | Year: 2014

This paper presents the results of the continuous measurements of surface ozone (O3), oxides of nitrogen (NOx) and methane (CH4) in a rural coastal location at Kannur (11.9°N, 75.4°E, 5m AMSL), India from November 2009 to December 2012. The maximum and minimum mixing ratios of surface O3 were observed in winter and monsoon seasons respectively. NOx concentration was high during mid-night to early morning and low during noontime. The diurnal variations of mixing ratios for NOx and O3 were anti-correlated. Monthly average maximum and minimum CH4 concentrations were observed in December and August respectively. The diurnal variations of CH4 were quite similar to that of NOx. A gradual build up of CH4 was observed during early morning hours of all days throughout the observational period. Further, the analyses of O3, NO, NO2 and NOx have been carried out and the correlation between O3 and its precursors is discussed in detail. The chemical analysis of air samples conducted to identify the main inorganic species present in air and their significance is presented. An attempt has been made to investigate the impact of concentration of Particulate Matter (PM10) present in the ambient air on the production of surface O3 at this location to explore the influence of PM10 on surface O3. © 2013 Elsevier B.V.


Mathew S.,Government Brennen College | Sunitha M.S.,National Institute of Technology Calicut
Information Sciences | Year: 2010

The fuzzy graph approach is more powerful in cluster analysis than the usual graph - theoretic approach due to its ability to handle the strengths of arcs effectively. The concept of node-strength sequence is introduced and is studied in a complete fuzzy graph. Two new connectivity parameters in fuzzy graphs namely, fuzzy node connectivity (κ) and fuzzy arc connectivity (κ′) are introduced and obtained the fuzzy analogue of Whitney's theorem. Fuzzy node cut, fuzzy arc cut and fuzzy bond are defined. Fuzzy bond is a special type of a fuzzy bridge. It is proved that at least one of the end nodes of a fuzzy bond is a fuzzy cutnode. It is shown that κ = κ′ for a fuzzy tree and it is the minimum of the strengths of its strong arcs. The relationships of the new parameters with already existing vertex and edge connectivity parameters are studied and is shown that the value of all these parameters are equal in a compete fuzzy graph. Also a new clustering technique based on fuzzy arc connectivity is introduced. © 2009 Elsevier Inc. All rights reserved.


Pradeep A.K.,University of Calicut | Pramod C.,Government Brennen College
Candollea | Year: 2013

Parasopubia hofmannii Pradeep & Pramod and Parasopubia hofmannii var. albiflora Pradeep & Pramod (Orobanchaceae) are two new taxa described from South India. They are compared with the Indian species Parasopubia delphinifolia (L.) H.-P. Hofm. & Eb. Fisch. Detailed descriptions, illustrations and taxonomical note are provided. A key for the identification of the Indian species of Parasopubia H.-P. Hofm. & Eb. Fisch. is also provided. © CONSERVATOIRE ET JARDIN BOTANIQUES DE GENÈVE 2013.


Venugopalan Nambiar M.,Government Brennen College
Journal of Advanced Zoology | Year: 2012

Monthal, is one of the tributary of Mane river. It forms an extensive system of small streams and rivulets when it closes to the point culminating with sea. it is rich with both mangrove flora and fauna. Due to extensive destruction of mangrove vegetation or land filling, depending fauna, more precisely the fishes were found severely affected and majority of the fishes are in endangered condition at least with respect to Mahe river system. The surrounding paddy fields, the breeding centre of many freshwater fishes, also filled for housing and other human activities and deposition of waste materials. Once, this area is popularly known for both freshwater and estuarine edible fishes. The present study forms status study of ichthyo-fauna of this river. There 13 edible fish species are identified and reported in the present study. It stresses the importance of urgent measure to conserve that ichthyo-fauna of this region which are vulnerable at present. Further the shelled fishes also seen depleted in its average landings. The water qualities of the river, such as, salinity, pH, biological parameters and presence of toxic heavy metals were examined by means of standard methods. The accumulation of toxic heavy metals leads the destruction of ichthyo-fauna and they enter into human body through food chain causes severe hazardous problems to human health.


Krishnan A.,Rajiv Gandhi Center for Biotechnology | Mahadevan C.,Rajiv Gandhi Center for Biotechnology | Mani T.,Government Brennen College | Sakuntala M.,Rajiv Gandhi Center for Biotechnology
Plant Cell, Tissue and Organ Culture | Year: 2015

Piper colubrinum Link., an exotic species, is a wild relative of cultivated black pepper (Piper nigrum L.), and shows high degree of resistance to the oomycete pathogen Phytophthora capsici, which causes the devastating ‘quick wilt’ disease in P. nigrum. Serine/threonine protein kinase (PcSTPK) is a prospective candidate gene identified from P. colubrinum for future genetic improvement of P. nigrum. RACE PCR amplified a full-length PcSTPK of 1.7 kbp which encodes 575 amino acid residues with a calculated molecular weight of 64.45 kDa. PcSTPK forms a part of a distinct clade in phylogeny analysis, sharing higher similarity to receptor-like protein kinase class of Ser/Thr protein kinases. Real-time qRT-PCR showed the enhanced expression of PcSTPK gene upon P. capsici inoculation and the maximum accumulation of STPK transcripts was observed at 12 h post inoculation. A Tobacco rattle virus (TRV)-based virus-induced gene silencing (VIGS) was established using Phytoene desaturase endogenous gene as a reporter. TRV:PcSTPK VIGS vector was infiltrated into young leaves of P. colubrinum. A time course study revealed that STPK transcript levels were significantly downregulated. Knock down of PcSTPK by VIGS increased the susceptibility to P. capsici infection, as evidenced by the appearance of foliar necrotic lesions and increased proliferation and sporulation of P. capsici on the leaf surface. We report the successful implementation of VIGS as a systemic strategy for defense gene functional validation in P. colubrinum and our data provide direct evidence for the possible role of PcSTPK in modulating antifungal defense response in the plant. © 2015, Springer Science+Business Media Dordrecht.


Josekutty E.J.,Government Brennen College | Josekutty E.J.,Thomas College | Biju P.,Government College | Biju P.,Thomas College | Augustine J.,Thomas College
Webbia | Year: 2016

Strobilanthes malabarica a new species of Strobilanthes from the South Western Ghats is described and illustrated. It is similar to S. aurita with its elliptic to lanceolate leaves, its inflorescences with basal involucral bracts, its bracts and bracteoles bearing glandular hairs, the calyx divided close to the base, a tubular ventricose corolla and the ellipsoidal pollen. It differs in having sparsely hispid leaves with setaceous margins, smaller oblanceolate bracts, a calyx with equal lobes that bear glandular hairs, and in the elliptic to lanceolate capsules with glabrous, areolate seeds. Notes on ecology and conservation status are also provided. © 2016 Dipartimento di Biologia, Università di Firenze

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