1,675 research outputs found

    On the Usage of the Faraday Effect as an Authentication Technique for Vegetable Oils

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    In this study we report on the measurements of the Verdet constant for olive and other vegetable oils. Study of samples stored for different periods at different storage conditions showed that each olive oil sample has a Verdet constant value depending on: production year, history of the sample (i.e. storage conditions) and geographical region. Photo and auto oxidations are found to have reverse effects on the value of the measured Verdet constant, on the one hand, photo-oxi- dation tends to decrease the Verdet constant, but on the other hand auto-oxidation tends to increase it. It is known that oils stored in room light had significantly lower tocopherol, carotenoid, and chlorophyll contents than did the same oils kept in the dark. For other vegetable oil samples, each vegetable oil was found to have a distinct Verdet constant value. Thus it is possible to differentiate vegetable oils making use of their respective Verdet constants. Preliminary results indicated the possibility to detect olive oil adulteration using the Faraday Effect, i.e. the effect could be suggested as a food authentication technique if calibration curves and standard Verdet constants values could be prepared for com-parison with those of samples under investigation

    Reconnection and acoustic emission of quantized vortices in superfluid by the numerical analysis of the Gross-Pitaevskii equation

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    We study numerically the reconnection of quantized vortices and the concurrent acoustic emission by the analysis of the Gross-Pitaevskii equation. Two quantized vortices reconnect following the process similar to classical vortices; they approach, twist themselves locally so that they become anti-parallel at the closest place, reconnect and leave separately.The investigation of the motion of the singular lines where the amplitude of the wave function vanishes in the vortex cores confirms that they follow the above scenario by reconnecting at a point. This reconnection is not contradictory to the Kelvin's circulation theorem, because the potential of the superflow field becomes undefined at the reconnection point. When the locally anti-parallel part of the vortices becomes closer than the healing length, it moves with the velocity comparable to the sound velocity, emits the sound waves and leads to the pair annihilation or reconnection; this phenomena is concerned with the Cherenkov resonance. The vortices are broken up to smaller vortex loops through a series of reconnection, eventually disappearing with the acoustic emission. This may correspond to the final stage of the vortex cascade process proposed by Feynman. The change in energy components, such as the quantum, the compressible and incompressible kinetic energy is analyzed for each dynamics. The propagation of the sound waves not only appears in the profile of the amplitude of the wave function but also affects the field of its phase, transforming the quantum energy due to the vortex cores to the kinetic energy of the phase field.Comment: 11 pages, 16 figures, LaTe

    Synthesis, Characterization and Antimicrobial Investigations of (Ag, Cu, Ni, Co,Mn andHg)Complexes With Schiff Base Derived From PVA andErythro-Ascorbic Acid Derivative

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    The aim of this work is the synthesis of new Schiff base derived from PVA and Erythro-ascorbic acid derivative (pentulosono-?-lactone-2,3-enedianisoate) and its metal complexes of biological significance. All synthesized compounds were characterized by Thin layer chromatography (TLC) and FTIR spectra and aldehyde was also characterized by (U.V-Vis), 1HNMR, 13CNMR and mass spectra. The synthesized Schiff base & its metal complexes were screened for theirinvitro antimicrobial activity against five pathogenic bacteria (Escherichia coli, Shigella dysentery,Klebsiellapneumonae,Staphylococcusaureus, Staphylococcus Albus) and two fungal (Aspergillus Niger,Yeast).The biological activity ofall complexes is higher than free Schiff base ligand andfollows the order: polymer < pol-Mn< pol-Ni< pol- Co ? pol-Cu ? pol-Ag ? pol-Hg.This means that metal chelation significantly affects the antimicrobial behavior of the organic ligand. Keywords: Schiff base, polymer metal complexes, antibacterial, antifungal, activity

    Interaction of Nonlinear Schr\"odinger Solitons with an External Potential

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    Employing a particularly suitable higher order symplectic integration algorithm, we integrate the 1-dd nonlinear Schr\"odinger equation numerically for solitons moving in external potentials. In particular, we study the scattering off an interface separating two regions of constant potential. We find that the soliton can break up into two solitons, eventually accompanied by radiation of non-solitary waves. Reflection coefficients and inelasticities are computed as functions of the height of the potential step and of its steepness.Comment: 14 pages, uuencoded PS-file including 10 figure

    The effect of Pomegranate Peels Aqueous Extract against Streptococcus Mutans and the Adherence to tooth surface in Comparison to Chlorhexidine Gluconate (in Vitro Study)

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    For centuries, nature has been an enormous source of agents of medical importance and this study was conducted to evaluate the antibacterial activity of aqueous extract of pomegranate peels against Streptococcus mutans by using agar diffusion technique and the adherence to tooth surface in comparison to chlorhexidine gluconate in vitro was also studied. This study revealed that pomegranate peels exhibit good antibacterial activity and this activity was found to be increased as the concentration of extract increased and the result also showed that the pomegranate peels aqueous extract was effective in inhibiting the adherence of Streptococcus mutans to tooth surface Keywords: pomegranate peels, streptococcus mutans, adherenc

    Spectroscopic approach of the interaction study of Ceftriaxone and human serum albumin

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    Under physiological conditions, interaction between ceftriaxone and human serum albumin was investigated by using fluorescence spectroscopy and ultra violet (UV) absorption spectrum. From spectral analysis, ceftriaxone showed a strong ability to quench the intrinsic fluorescence of human serum albumin (HSA) through a static quenching procedure. The binding constant (k) is estimated as K=1.02× 103 M-1 at 298 K. Fourier transform infrared spectroscopy (FT-IR) spectroscopy with Fourier self-deconvolution technique was used to determine the protein secondary structure and drug binding mechanisms. The observed spectral changes indicated the formation of H-bonding between ceftriaxone and HSA molecules at higher percentage for -helix than for the -sheets.This work was supported by the German Research Foundation DFG Grant No. DR228/24-2

    Synthesis and Charactrization of New Schiff Base Derived from PVA and Erythroascorbic Acid Derivative and Study Its Effect on the Activity of ACh Enzyme (In Vitro)

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    Schiff base derived from PVA and Erythroascorbic acid derivative (pentulosono-?-lactone-2, 3-enedianisoate) was synthesized and characterized by Thin Layer Chromatography (TLC) and FTIR spectra, aldehyde was also characterized by (U.V-Vis), 1HNMR, 13CNMR and mass spectra. The inhibitory effect of prepared polymer on the activity of human serum Cholinesrerase has been studied in vitro. The polymer showed a remarkable activity at low concentration (4.5*10-3 – 4.5*10-8 M). Keywords: Schiff base, PVA, Acetylcholinesterase

    Biochemical Evaluation of some Natural Feed Additives against Dexamethasone-induced Metabolic Alterations in Rabbits

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    Glucocorticoid therapy is limited by numerous metabolic adverse effects associated with long term exposure to excess doses. Therefore, the present study aims to determine the possible protective effects of date palm and/or Saccharomyces cerevisiae probiotics on dexamethasone-induced metabolic changes in rabbits. 25 healthy male white New Zealand rabbits were grouped into group 1 (control), group 2 (2 mg/kg bw/day dexamethasone I/M), group 3 (0.5 g/kg/day date palm flesh+2 mg/kg bw/day dexamethasone I/M), group 4 (1g/kg/day S. cerevisiae probiotic + 2 mg/kg bw/day dexamethasone I/M), group 5 (date palm flesh + S. cerevisiae probiotic + dexamethasone at the aforementioned doses). Dexamethasone injection resulted in marked increases (p≤0.05) in hepatic MDA concentration and catalase activity, as well as significant decreases in hepatic GSH concentration and body weight gain. The serum levels of glucose, lipid profile (TG, cholesterol, VLDL, LDL/HDL risk ratio), and liver function biomarkers (serum total proteins, albumin, ALT, ALP) showed significant variations (P≤0.05) between control and dexamethasone treated group. The ameliorative effect of date palm fruit and/or probiotics (S. cerevisiae) was markedly indicated by restoration of these tested parameters to near normalcy. Therefore, the co-treatment with date or S. cerevisiae could be considered of great interest as potential feed additives for reduction of the adverse metabolic effects induced by dexamethasone in rabbits
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