EVALUATION OF ANTIDEPRESSANT ACTIVITY OF ETHANOLIC EXTRACT OF DIPTERCANTHUS PROSTRATUS NEES

Objective: The major objective of the study is to evaluate the antidepressant activity of ethanolic extract of Dipteracanthus prostratus Nees using rats. The study also aims to assess the effect of the extract on behavioural pattern of treated rats. Methods: The antidepressant activity of the ethanolic extract of Dipteracanthus prostratus was evaluated using Forced swim test (FST). The effect of the extract on the behavioral pattern was assesssed by an Open field test. The oral doses of 500 mg/kg and 250 mg/kg of the extract were fixed after conducting acute toxicity studies. Imipramine (30 mg/kg) was used as the standard. Results: It was observed from the study that the ethanolic extract of Dipteracanthus prostratus at higher concentration showed significantly (p<0.01) reduction in immobility in forced swim test model of depression after repeated administration for 14 d. The results were comparable to the standard drug Imipramine. However, the extract did not any significant activity after acute administration. Neither the ethanolic extract of Dipteracanthus prostratus nor the standard drug imipramine produced any overt behavioural change or motor dysfunction in the open field test. Conclusion: The present study demands a further detailed investigation on the antidepressant and other possible CNS activities of Dipteracanthus prostrates

Wave refraction and prediction of breaker parameters along the Kerala coast, India

128-134Numerical wave refraction study for the Kerala coast has been carried out for waves representing southwest monsoon (June - September), northeast monsoon (October - February) and fair weather period (February - May). Distribution of wave heights vary significantly from place to place due to wave refraction and shoaling. The convergence and divergence of wave energy induce non-uniform distribution of wave heights during the monsoon period. Ezhimala promontory causes waves to refract considerably along the coastline of Cannanore, Badagara and Mahe during October to February, whereas the headland at Thankasseri induces divergence of wave energy along Quilon and Varkallai. Vypin experiences convergence of wave energy almost throughout the year

The ion exchange properties of nanosized cerium molybdo iodate and cerium phospho iodate

Nanoparticles of cerium molybdo iodate and cerium phospho iodate, tetravalent metal acid (TMA) salts were prepared by chemical co-precipitation method.The protons present in the structural hydroxyl groups indicate good potential for TMA salts to exhibit solid state proton conduction. The samples in its protonated form weresubjected to ion exchange capacity studies. The data revealed that the samples act as agood ion exchanger

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Electrical conductivity and ion exchange studies of nano sized cerium (IV) tungsto iodate — A new cation exchanger

488-490Nano particles of cerium tungsto iodate, a tetravalent metal acid salt, have been prepared by chemical co-precipitation method. The particle size of the sample has been calculated from its X-ray diffraction pattern and the average grain size is found to be 25 nm. The size is further characterized by SEM, TEM and FTIR analyses. Its dielectric behaviour at various temperatures (50<span style="mso-bidi-font-family: " times="" new="" roman""="" lang="EN-GB">°-110°C) and frequencies is also investigated. The dielectric constant values increase with the decrease in frequency and the increase in temperature. Moreover, the sample in its protonated form is subjected to ion exchange capacity studies. The data reveals that the sample works as a good ion exchanger. </span

Characterization, dielectric and optical studies of nano-cerium phospho iodate synthesized by chemical co-precipitation method

299-304Nanoparticles of cerium phospho iodate belong to the class of tetravalent metal acid (TMA) salt are synthesized by chemical co-precipitation method. The particle size obtained from X-ray diffraction spectrum is found to be in the range of 30 nm. Surface morphology is studied from SEM images. The chemical composition of the sample has been verified using EDAX. The optical studies are carried out using FTIR and UV techniques. The stretching and bending frequencies of the sample are studied using the FTIR spectrum. The optical direct band gap of the material calculated using the Tauc’s relation is found to be 3.4 eV. The dielectric behaviour of the samples is studied at various temperatures and frequencies and ac electrical conductivity is also calculated. It is found that dielectric constant decreases with increase in frequency

Characterization, dielectric and optical studies of cerium molybdo tungstate nanoparticles

893-898Nanoparticles of cerium molybdo tungstate (CMT) have been prepared by chemical co-precipitation method. The average particle size is determined from X-ray diffraction studies. The nanoparticle nature of the sample is verified using SEM, TEM and AFM images. The surface morphology of the sample is studied from SEM image. The FTIR spectrum has been used to study the stretching and bending frequencies of molecular groups in the sample. Temperature and frequency dependence of the dielectric constant and ac electrical conductivity have been investigated. The dielectric permittivities of the samples are evaluated from the observed capacitance values in the frequency range 100 Hz-1 MHz and in the temperature range 50°-110°C. It has been found that with increasing frequency, the dielectric constant decreases. The high value of dielectric constant at low frequencies may mainly be due to the space charge and rotational polarization. Also, the dielectric constant increases with increase in temperature for fixed frequencies. As the temperature increases more and more dipoles will be oriented resulting in an increase in molecular dipole moment. The ac electrical conductivity is evaluated from the permittivity studies. The absorption spectra of the sample in the UV range are recorded. From the analysis of the absorption spectra, the material is found to have a direct band gap of 3.2 eV

Quantitative representation of floral colors

International audienceHuman and insect pollinator perceived floral colors of 81 species of angiosperms (flowering plants) from Trivandrum (Kerala, India) was represented using the CIE 1976 L*a*b* color space and color hexagon, respectively. The floral color difference among human perceived red, yellow, and blue-hued flowers and that of each flower from its respective pure hue was calculated using the CIE E 2000 formula. Human perceived floral color difference values were consistently higher than 3.5, indicating the uniqueness of floral colors. Flowers perceived red and yellow by humans were dominant and of comparable proportions. Insect pollinators perceive most of the flowers as blue-green. Quantitative representation of human and pollinator perceived floral colors would be invaluable to understand the information broadcasted by flowers. It can form the basis of flower grading in the floriculture industry and underpin objectivity in evolving the framework for national pollinator strategies

Chromatic exclusivity hypothesis and the physical basis of floral color

International audienceThis paper presents the results of floral spectral studies on 1275 flowers from India, Brazil, Israel, Germany, and Norway. Floral spectral reflectance from 400 to 700 nm (nm) was used to quantitatively represent ‘human-perceived’ color of flowers in Red, Green, Blue color space. Floral spectral reflectance from 350 to 600 nm was used to discern and objectively represent ‘insect pollinator-perceived’ flower colors in color hexagon. We leverage the advantage offered by ‘quantified human perception’ provided by ‘human-perceived’ floral colors to represent the distribution of floral hues and uncover the relationship between the composition of incoming solar radiation and predominant ‘human-perceived’ floral colors at the tropics and the higher latitudes. Further, the observed species-level mutual exclusivity of ‘insect pollinator-perceived’ floral colors is stated as chromatic exclusivity hypothesis. We compare ‘human-perceived’ and ‘insect pollinator-perceived’ floral colors at Trivandrum (India) and provide a physical explanation for short and long ‘wavelength triads’ of insect pollinator and human visual sensitivity respectively

Evidence for intergranular tunnelling in polyaniline passivated α-Fe nanoparticles

Nanoparticles are of immense importance both from the fundamental and application points of view. They exhibit quantum size effects which are manifested in their improved magnetic and electric properties. Mechanical attrition by high energy ball milling (HEBM) is a top down process for producing fine particles. However, fineness is associated with high surface area and hence is prone to oxidation which has a detrimental effect on the useful properties of these materials. Passivation of nanoparticles is known to inhibit surface oxidation. At the same time, coating polymer film on inorganic materials modifies the surface properties drastically. In this work a modified set-up consisting of an RF plasma polymerization technique is employed to coat a thin layer of a polymer film on Fe nanoparticles produced by HEBM. Ball-milled particles having different particle size ranges are coated with polyaniline. Their electrical properties are investigated by measuring the dc conductivity in the temperature range 10–300 K. The low temperature dc conductivity (I–V ) exhibited nonlinearity. This nonlinearity observed is explained on the basis of the critical path model. There is clear-cut evidence for the occurrence of intergranular tunnelling. The results are presented here in this paperCochin University of Science and TechnologyNanotechnology 17 (2006) 4765–477