8,858 research outputs found

    Development and application of rice starch based edible coating to improve the postharvest storage potential and quality of plum fruit (<i>Prunus salicina</i>)

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    The study investigated the possibility of enhancing the shelf life of plum fruit coated with rice starch-ι-carrageenan (RS-ι-car) composite coating blended with sucrose fatty acid esters (FAEs). Film solution (starch 3%, carrageenan 1.5% and FAEs 2%) was prepared by mixing the ingredients and properties of stand-alone films (physical, mechanical, barrier and surface morphology) were studied before applying the coating on fruit surface. Fruit were stored at 20 °C for 3 weeks and analyzed for weight loss, ethylene production, respiration rate, color change, firmness, and titratable acidity (TA) and soluble solid content (SSC). Surface morphology of stand-alone film and fruit surface (after applying on the plum fruit) was studied using scanning electron microscopy (SEM). Phytochemical analysis was performed during the storage period and total phenolic content (TPC), total antioxidant capacity (TAC), flavonoid content (FC) and free radical scavenging activity were determined. The rice starch composite coating was shown to be effective in reducing both weight loss (WL) and respiration rate and inhibiting the endogenous ethylene production when compared to the uncoated control fruit stored at room temperature (p &lt; 0.05). TPC, TAC, FC and free radical scavenging activity was unaffected in the coated fruit throughout the storage period (p &lt; 0.05). The findings reported in this study indicate that the RS-ι-car-FAEs coating prolongs the shelf life and maintains the overall quality of plum fruit during storage and could potentially be commercialized as a new edible coating for the plum fruit industry

    Bumper catch of Pampus chinensis (Euphrasen, 1788) landed at New Ferry Wharf, Mumbai

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    Pomfrets are considered a valuable seafood delicacy and enjoy great market demand in Maharashtra. An unprecedented high catch (Plate 1) of Pampus chinensis commonly known as ‘Chinese pomfret was landed by trawlers at New Ferry Wharf on 20-10-07. The fishing ground was towards northwest at a depth of 30-40 m

    Exchange bias in GeMn nanocolumns: the role of surface oxidation

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    We report on the exchange biasing of self-assembled ferromagnetic GeMn nanocolumns by GeMn-oxide caps. The x-ray absorption spectroscopy analysis of this surface oxide shows a multiplet fine structure that is typical of the Mn2+ valence state in MnO. A magnetization hysteresis shift |HE|~100 Oe and a coercivity enhancement of about 70 Oe have been obtained upon cooling (300-5 K) in a magnetic field as low as 0.25 T. This exchange bias is attributed to the interface coupling between the ferromagnetic nanocolumns and the antiferromagnetic MnO-like caps. The effect enhancement is achieved by depositing a MnO layer on the GeMn nanocolumns.Comment: 7 pages, 5 figure

    On the optical properties of Ag^{+15} ion-beam irradiated TiO_{2} and SnO_{2} thin films

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    The effects of 200-MeV Ag^{+15} ion irradiation on the optical properties of TiO_{2} and SnO_{2} thin films prepared by using the RF magnetron sputtering technique were investigated. These films were characterized by using UV-vis spectroscopy, and with increasing irradiation fluence, the transmittance for the TiO_{2} films was observed to increase systematically while that for SnO_{2} was observed to decrease. Absorption spectra of the irradiated samples showed minor changes in the indirect bandgap from 3.44 to 3.59 eV with increasing irradiation fluence for TiO_{2} while significant changes in the direct bandgap from 3.92 to 3.6 eV were observed for SnO_{2}. The observed modifications in the optical properties of both the TiO_{2} and the SnO_{2} systems with irradiation can be attributed to controlled structural disorder/defects in the system.Comment: 6 pages, ICAMD-201

    Evolution of magnetic phases and orbital occupation in (SrMnO3)n/(LaMnO3)2n superlattices

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    The magnetic and electronic modifications induced at the interfaces in (SrMnO3_{3})n_{n}/(LaMnO3_{3})2n_{2n} superlattices have been investigated by linear and circular magnetic dichroism in the Mn L2,3_{2,3} x-ray absorption spectra. Together with theoretical calculations, our data demonstrate that the charge redistribution across interfaces favors in-plane ferromagnetic (FM) order and eg(x2y2)e_{g}(x^{2}-y^{2}) orbital occupation, in agreement with the average strain. Far from interfaces, inside LaMnO3_3, electron localization and local strain favor antiferromagnetism (AFM) and eg(3z2r2)e_{g}(3z^{2}-r^{2}) orbital occupation. For n=1n=1 the high density of interfacial planes ultimately leads to dominant FM order forcing the residual AFM phase to be in-plane too, while for n5n \geq 5 the FM layers are separated by AFM regions having out-of-plane spin orientation.Comment: accepted for publication as a Rapid Communication in Physical Review

    A method for measuring the Neel relaxation time in a frozen ferrofluid

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    We report a novel method of determining the average Neel relaxation time and its temperature dependence by calculating derivatives of the measured time dependence of temperature for a frozen ferrofluid exposed to an alternating magnetic field. The ferrofluid, composed of dextran-coated Fe3O4 nanoparticles (diameter 13.7 nm +/- 4.7 nm), was synthesized via wet chemical precipitation and characterized by x-ray diffraction and transmission electron microscopy. An alternating magnetic field of constant amplitude (H0 = 20 kA/m) driven at frequencies of 171 kHz, 232 kHz and 343 kHz was used to determine the temperature dependent magnetic energy absorption rate in the temperature range from 160 K to 210 K. We found that the specific absorption rate of the ferrofluid decreased monotonically with temperature over this range at the given frequencies. From these measured data, we determined the temperature dependence of the Neel relaxation time and estimate a room-temperature magnetocrystalline anisotropy constant of 40 kJ/m3, in agreement with previously published results
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