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Ullattil S.G.,University of CalicutKerala | Periyat P.,University of CalicutKerala | Periyat P.,Central University of Kerala
Solar Energy | Year: 2017

A facile and rapid synthesis of randomly distributed mesoporous anatase TiO2nanoparticles for DSSC application using microwave method is reported here. Nanocrystalline anatase TiO2is achieved by a sol microwave power strategy, where low microwave power intensity (300 and 600 W) for 5 min irradiation has been implemented. As synthesized anatase TiO2nanoparticles have been characterized by a range of different techniques such as XRD, SEM, TEM and BET surface area analysis. These anatase TiO2nanoparticles possessed high surface area up to 210 m2 g−1. Nanocrystalline nature and anatase phase purity were revealed from XRD. SEM studies have shown that the anatase TiO2powder synthesized were appeared as spherical aggregates and the nano size of single particles (∼10 nm) were confirmed by TEM analysis. These anatase TiO2nanoparticles were successfully employed as the working electrode for DSSC and a systematic investigation of the performance of DSSC constructed with standard N719 dye with conventional iodide/triiodide (I−/I3 −) has demonstrated an efficiency of 6.6% under 100% sunlight with 55% of IPCE. © 2017


Janeesha A.P.,University of CalicutKerala | Nampy S.,University of CalicutKerala
Phytotaxa | Year: 2016

The genus Henckelia Sprengel (1817: 402) was re-established by Weber & Burtt (1997), with approximately 180 species, to include most of the Malesian, Sri Lankan and south Indian species of Didymocarpus Wallich (1819: 378). Weber et al. (2011) and Middleton et al. (2013) based on molecular data redefined the genus and included only 56 species. Subsequently three more species were added to the genus, H. pradeepiana Nampy, Manudev & Weber in Manudev et al. (2012: 119), H. sivagiriensis (Rajakumar et al. 2009: 481) Kumar (2014: 149) and H. bracteata Janeesha & Nampy (2015: 53) while Middleton et al. (2015) transferred H. smitinandii (Burtt 2001: 89) Middleton & Möller in Weber et al. (2011: 776) to the genus Chayamaritia Middleton & Möller (2015: 1961). At present the genus includes 58 species distributed in Sri Lanka, southern and northeastern India, Nepal, Bhutan, southern China, northern Vietnam, northern Laos and northern Thailand. © 2016 Magnolia Press.


Anju M.,University of CalicutKerala | Renuka N.K.,University of CalicutKerala
RSC Advances | Year: 2015

A magnetically separable graphene-iron oxide nanotube composite was synthesised for the first time via an adept template free hydrothermal route. The physical characterization of the material was done using XRD, FTIR, SEM, TEM and VSM analysis. A mechanism analogous to the Kirkendall effect, involving the diffusion of Fe2+ ions and consequent expansion of voids leading to the formation of hollow iron oxide nanotubes has been proposed in accordance with the results obtained from XRD and TEM analysis. The composite turned out to be an excellent adsorbent for the removal of toxic Cr(vi) ions. Adsorptive removal and magnetic separation was achieved quickly within 60 seconds which highlights the efficiency of the prepared hybrid. The isotherm analysis indicated that the adsorption data can be represented by the Langmuir isotherm model. The superior adsorptive removal efficiency of the composite can be attributed to the synergistic effect between graphene and the iron oxide nanotubes. Through this report, we have demonstrated the first attempt of a template free synthesis of iron oxide nanotubes and their incorporation on graphene sheets. Subsequently the composite's ability as an adsorbent was evaluated in its efficiency for Cr(vi) removal. © The Royal Society of Chemistry.


Ashraf K.,University of CalicutKerala | Mohamed Haneefa K.,University of CalicutKerala
Annals of Library and Information Studies | Year: 2016

The study investigates the scholarly use of social media by the doctoral students in the University of Calicut, Kerala. Structured questionnaires were used to collect data from a representative sample of 160 doctoral students. The analysis revealed that majority of the students are aware and use social media for scholarly purpose and used mainly for locating scholarly content and current awareness. Wikis and social networking sites are the most widely used social media by the students. © 2016, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.


Bhagyanathan N.K.,University of CalicutKerala | Thoppil J.E.,University of CalicutKerala
Turkish Journal of Biology | Year: 2016

The present study evaluated the genotoxic effect of aqueous extract of C. sarcomedium Meve & Liede and its protective role in chromosomal aberrations induced by 2% hydrogen peroxide (H2O2) on Allium cepa root meristem. Our results showed that the C. sarcomedium extract induced major chromosomal aberrations, viz., nuclear lesions, chromosome breaks, chromosome laggards, vagrance, stickiness, and bridges. These are irreversible in nature and indicate that the plant is a potent clastogen. Total chromosome aberrations were more frequent with increase in exposure time and concentrations of plant extract. For antigenotoxic screening, three different modes of treatment were used: pretreatment, posttreatment, and simultaneous treatment. The significant induction of a wide spectrum of chromosomal aberrations and the reduction in mitotic index effected by the aqueous extract reinforced the genotoxic potential of the plant. The modulatory effect of plant extract was expressed in terms of inhibition percentage and had an excellent effect in reversing chromosomal aberrations induced by H2O2. Dose-dependent results suggest the genotoxic and antigenotoxic effect of C. sarcomedium on onion root tips. These findings offer a useful basis for further investigations on C. sarcomedium, a shrub with a broad array of prospective therapeutic activities. © TÜBİTAK.


Narendran T.C.,University of CalicutKerala | Van Achterberg C.,Naturalis Biodiversity Center
ZooKeys | Year: 2016

A total of 16 genera and 68 species of Chalcididae of Vietnam are taxonomically treated. Thirteen new species are described; the remaining 55 species are keyed, redescribed or provided with a diagnosis. Among these 37 species and eleven genera are recorded for the first time from Vietnam. The thirteen new species are: Antrocephalus neogalleriae Narendran & van Achterberg, sp. n.; Brachymeria neowiebesina Narendran & van Achterberg, sp. n., B. semirusula Narendran & van Achterberg, sp. n., Dirhinus neoclaviger Narendran & van Achterberg, sp. n., Epitranus narendrani van Achterberg, sp. n., E. neonigriceps Narendran & van Achterberg, sp. n., Heydoniella vietnamensis Narendran & van Achterberg, sp. n., Megachalcis vietnamicus Narendran & van Achterberg, sp. n., Notaspidium vietnamicum Narendran & van Achterberg, sp. n., Oxycoryphe neotenax Narendran & van Achterberg, sp. n., Sthulapada neopadata Narendran & van Achterberg, sp. n., S. vietnamensis Narendran & van Achterberg, sp. n., and Tanycoryphus masii Narendran & van Achterberg, sp. n. The newly recorded genera are: Antrocephalus Kirby, 1883; Haltichella Spinola, 1811; Heydoniella Narendran, 2003; Hockeria Walker, 1834; Kriechbaumerella Dalla Torre, 1894; Notaspidium Dalla Torre, 1897; Oxycoryphe Kriechbaumer, 1894; Psilochalcis Kieffer, 1904; Sthulapada Narendran, 1989; Tanycorphus Cameron, 1905, and Trigonura Sichel, 1865. The following known species are recorded for the first time from Vietnam: Antrocephalus decipiens (Masi, 1929); A. lugubris (Masi, 1932); A. maculipennis (Cameron, 1905); A. nasutus (Holmgren, 1869); A. sepyra (Walker, 1846); A. validicornis (Holmgren, 1868); Brachymeria alternipes (Walker, 1871); B. aurea (Girault, 1915); B. coxodentata Joseph, Narendran & Joy, 1972; B. euploeae (Westwood, 1837); B. hime Habu, 1960; B. jambolana Gahan, 1942; B. kamijoi Habu, 1960; B. lugubris (Walker, 1871); B. marmonti (Girault, 1924); B. minuta (Linnaeus, 1767); B. scutellocarinata Joseph, Narendran & Joy, 1972; B. shansiensis Habu, 1961; B. taiwana (Matsumura, 1910); Dirhinus anthracia Walker, 1846; D. claviger Bouček & Narendran, 1981; Epitranus albipennis Walker, 1874; E. ater Bouček, 1982; E. gauldi Bouček, 1982; E. oxytelus Bouček, 1982; E. ramnathi (Mani & Dubey, 1973); Haltichella delhensis Roy & Farooqi, 1984; H. nipponensis Habu, 1960; Hockeria bangalorica Narendran, 1989; H. guptai Narendran, 1989; Kriechbaumerella ayyari (Gahan, 1919); K. cordigaster Roy & Farooqi, 1984; K. destructor (Waterston, 1922); K. nepalensis Narendran, 1989; Oxycoryphe scutellatus Narendran, 1989; Psilochalcis carinigena (Cameron, 1907), and Trigonura luzonensis Narendran, 1987. Brachymeria calopeplae Joseph, Narendran & Joy, 1972, is treated as a valid species. © 2016, Pensoft Publishers. All rights reserved.


Nikhila M.P.,University of CalicutKerala | Renuka N.K.,University of CalicutKerala
RSC Advances | Year: 2016

Hollow nanostructures have inspired curiosity for their fascinating properties that originate from the unique structure, combining their free inner nanospace and chemical functionality of boundary materials. Herein, we provide the first account on the fabrication of single crystalline multishelled titania hollow nanospheroids under mild conditions through a template free solvothermal method. Judicious control over the reaction time revealed that the synthetic stages pass through hollow spheres of various interiors, all of which are single crystalline in nature, which makes a significant advance in this field. The formation mechanism is explained by Ostwald ripening based dissolution and the recrystallization process. Evidence for secondary Ostwald ripening that leads to a multishelled metal oxide structure is presented for the first time. Another highlight of the report is the enhanced application potential of the material that the multishelled structure offers. The material was observed to be an outstanding photocatalyst than all of the titania structures previously reported under identical experimental conditions, which arises due to the multiple reflection of light from the complex interiors. © 2016 The Royal Society of Chemistry.


Dharsana M.V.,University of CalicutKerala | Sindhu S.,University of CalicutKerala
Materials Letters | Year: 2016

Nanoparticles of antimony selenide, a binary metal chalcogenide, have been synthesized hydrothermally with ethylene glycol as capping agent. In short reaction time of 1 h, uniform sized particles of approximately 200 nm with such morphology is reporting for the first time. The compound formation is confirmed using XRD, morphology and composition using SEM and EDAX. The optical property of the material is analyzed using UV–Vis absorption spectrum, which shows a panchromatic behavior, covering the entire spectrum with absorption extending from visible to near IR region. The bandgap energy (Eg) of the material obtained from Tauc plot is 1.2 eV. On account of this panchromatic nature of Sb2Se3 nanoparticles, their performance efficiency as light harvester in solar cell is analyzed from I-V measurements under 1 Sun illumination. © 2016 Elsevier B.V.


Ullattil S.G.,University of CalicutKerala | Periyat P.,University of CalicutKerala | Periyat P.,Central University of Kerala
Journal of Materials Chemistry A | Year: 2016

A one pot gel combustion synthetic strategy has been developed for the first time towards the rapid formation of self-doped black anatase TiO2-x (BAT) using titanium butoxide, diethylene glycol (DEG) and water as the only precursors. This swiftly formed nanoplatform was occupied with a high concentration of surface defect sites, especially Ti3+ and oxygen vacancy sites in excess. The in (lattice) and out (surface) defect states were confirmed by Raman, XPS and TEM analysis. These defect-enriched features enabled 33% more photocatalytic activity for BAT than the commercially available photocatalyst Degussa-P25 under solar illumination. © The Royal Society of Chemistry 2016.


Vazhangat P.,University of CalicutKerala | Thoppil J.E.,University of CalicutKerala
Turkish Journal of Biology | Year: 2016

The present study investigates the cytotoxic and genotoxic effects of two frequently employed synthetic food colorants, lemon yellow and orange red, using an Allium cepa assay. Uptake of food colorants by root cells at different concentrations and varied exposures significantly altered the cytogenetic system, membrane integrity, mitochondrial function, root growth, and cell division. The food colorants induced significant DNA damage, micronucleus formation, and other severe chromosomal aberrations at genetic level and inhibited cell division as well as root growth. Severe DNA damage, membrane damage, and metabolic inactivation observed in the result are indicative of apoptotic cell death. These results confirm the possible dose-dependent toxicity of these food colorants in plant systems. The chromosomes of plants and animals are morphologically similar and appear to respond towards mutagens in a similar way like mammals, indicating possible damage to the DNA of humans when these colorants are used indiscriminately. © TÜBİTAK.

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