37 research outputs found

    Quantum correlated light pulses from sequential superradiance of a condensate

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    We discover an inherent mechanism for entanglement swap associated with sequential superradiance from an atomic Bose-Einstein condensate. Based on careful examinations with both analytical and numerical approaches, we conclude that as a result of the swap mechanism, Einstein-Podolsky-Rosen (EPR)-type quantum correlations can be detected among the scattered light pulses.Comment: 10 pages, 6 figure

    Quantum-measurement backaction from a Bose-Einstein condensate coupled to a mechanical oscillator

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    We study theoretically the dynamics of a hybrid optomechanical system consisting of a macroscopic mechanical membrane magnetically coupled to a spinor Bose-Einstein condensate via a nanomagnet attached at the membrane center. We demonstrate that this coupling permits us to monitor indirectly the center-of-mass position of the membrane via measurements of the spin of the condensed atoms. These measurements normally induce a significant backaction on the membrane motion, which we quantify for the cases of thermal and coherent initial states of the membrane. We discuss the possibility of measuring this quantum backaction via repeated measurements. We also investigate the potential to generate nonclassical states of the membrane, in particular Schrödinger-cat states, via such repeated measurements

    Quantum measurement backaction from a BEC coupled to a mechanical oscillator

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    We study theoretically the dynamics of a a hybrid optomechanical system consisting of a macroscopic mechanical membrane magnetically coupled to a spinor Bose-Einstein condensate via a nanomagnet attached at the membrane center. We demonstrate that this coupling permits us to monitor indirectly the center-of-mass position of the membrane via measurements of the spin of the condensed atoms. These measurements normally induce a significant backaction on the membrane motion, which we quantify for the cases of thermal and coherent initial states of the membrane. We discuss the possibility of measuring that quantum backaction via repeated measurements. We also investigate the potential to generate non-classical states of the membrane, in particular Schrodinger cat states, via such repeated measurements.Comment: 14 pages, 4 figures. Submitted to PR

    Extending the definition of modularity to directed graphs with overlapping communities

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    Complex networks topologies present interesting and surprising properties, such as community structures, which can be exploited to optimize communication, to find new efficient and context-aware routing algorithms or simply to understand the dynamics and meaning of relationships among nodes. Complex networks are gaining more and more importance as a reference model and are a powerful interpretation tool for many different kinds of natural, biological and social networks, where directed relationships and contextual belonging of nodes to many different communities is a matter of fact. This paper starts from the definition of modularity function, given by M. Newman to evaluate the goodness of network community decompositions, and extends it to the more general case of directed graphs with overlapping community structures. Interesting properties of the proposed extension are discussed, a method for finding overlapping communities is proposed and results of its application to benchmark case-studies are reported. We also propose a new dataset which could be used as a reference benchmark for overlapping community structures identification.Comment: 22 pages, 11 figure

    Purification and characterisation of laccase from lactarius volemus and its application in removal of phenolic compounds from fruit juice

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    Laccases are multicopper oxidases (EC 1.10.3.2.), widely distributed in fungi, higher plants and bacteria. In this research, a laccase from Lactarius volemus (Russulaceae) was purified by 73.08 fold using precipitate of saturation (NH4)2SO4, DEAE-cellulose and Sephacryl S200. It was shown that purified enzyme was homogeneous in term of SDS-PAGE with molecular mass estimated of 30 kDa. The pH was optimal at 4.0, enzyme was stable at pH 3.0-5.0 and optimal temperature was at 50°C. Cu2+ and Fe2+ were activated to the purified laccase enzyme, and it was partially inhibited by 5 mM concentration of some metal salts and EDTA, urea, SDS, L-cysteine, dithioeritritol and ?-mercaptoethanol. In addition, it was investigated whether the purified and characterized laccase enzyme would remove the phenolic compound of some fruit juices which are responsible for haze formation and browning during storage. Their application led to reduction of total phenolic compounds for apple, apricot, cherry and grape juice. As a result, the effect of these enzymatic treatments on total phenol content and clarity of the juice were evaluated using a central composite design. This laccase enzyme had potential application in food processing

    Collectively Induced Many-Vortices Topology Via Rotatory Dicke Quantum Phase Transition

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    We examine the superradiance of a Bose-Einstein condensate pumped with a Laguerre-Gaussian laser of high winding number, e.g., l = 7. The laser beam transfers its orbital angular momentum (OAM) to the condensate at once due to the collectivity of the superradiance. An l-fold rotational symmetric structure emerges with the rotatory superradiance. l number of single-charge vortices appear at the arms of this structure. Even though the pump and the condensate profiles initially have cylindrical symmetry, we observe that it is broken to l-fold rotational symmetry at the superradiance. Breaking of the cylindrical symmetry into the l-fold symmetry and OAM transfer to the condensate become significant after the same critical pump strength. Reorganization of the condensate resembles the ordering in the experiment by Esslinger and colleagues (2010 Nature 264 1301). We numerically verify that the critical point for the onset of the reorganization, as well as the properties of the emitted pulse, conform to the characteristics of superradiant quantum phase transition.WoSScopu

    Combined usage of testosterone and nandrolone may cause heart damag

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    The aim of this study is to determine the effects of combined application of testosterone and nandrolone on male rabbits during adolescence period for biochemical values which are indicators of damage to heart, liver and kidney. Seven male New Zealand white rabbits, 60-days old, were used in this study. Testosterone (10 mg/kg) + nandrolone deconoate (10 mg/kg) were injected simultaneously to the rabbits in an intramuscular manner once in 1 week for a period of 12 weeks. Blood samples were taken in 0, 4, 8 and 12 weeks. Serum creatine kinase-MB, lactate dehydrogenase, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl-transferase, creatinine and blood urea nitrogen were measured with an auto-analyzer. Combined use of testosterone and nandrolone caused (p < 0.05) increase in serum creatine kinase-MB activity, but no statistical changes (p > 0.05) were determined in other parameters. As a result, it can be concluded that the use of testosterone plus nandrolone simultaneously during early ages may cause heart damage.Key words: Testosterone, nandrolone, creatine kinase-MB.

    Expression of cytosolic and noncytosolic carbonic anhydrase enzymes from bovine brain membrane

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    Carbonic anhydrase is an enzyme that takes responsibility in inhalation function but, until today, carbonic anhydrase is not examined if it is present in the bovine brain membrane or not. The enzyme carbonic anhydrase was purified and separately characterized according to the bonding forms in 4 steps such as outer peripheral, cytosolic, inner peripheral and integral. Affinity chromatography was used for purification of the enzyme in all four steps. The affinity column was prepared with sepharose-4B-L-tyrosine-sulphanilamide. Purified carbonic anhydrase was obtained at each step. Enzyme activity was measured by CO 2 hydratase activity and esterase activity methods. Optimum pH and optimum temperature were defined for purified enzymes at each step. Morover molecular weight and purity were detected by gel filtration and SDS-PAGE electrophorose. In addition, the enzyme's Km and n max values were found with the Lineweaver- Burk method. The obtained results are discussed in comparison with other mammalian carbonic anhydrases. Carbonic anhydrase was shown to be exist in bovine brain membrane and this enzyme was optimized

    Purification and properties of carbonic anhydrase from bone marrow

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    In this work, the carbonic anhydrase was purified from bovine bone marrow and investigated its kinetic properties. Carbonic anhydrase was purified from bovine bone marrow using affinity chromatography by sepharose 4B-L-tyrosine sulphanilamide. During purification steps, the activity of enzyme was measured using p-nitrophenyl acetate at pH: 7.4. Optimum pH and optimum temperature values for bovine bone marrow carbonic anhydrase were determined and then K m and Vmax values for the same substrate were obtained by means of Linewearver-Burk graphics. The purification degree for bovine bone marrow was calculated. The Vmax, and Km values at optimum pH and at 20 °C for the substrate (p-nitrophenyl acetate) were 120.418 u?mol/L min and 2.409 x 103 mM, respectively. The K1 and I50 values for sulfanilamide, KSCN, NaN3 and acetazolamide were determined in bovine bone marrow carbonic anhydrase

    Experimental study to remediate acid fuchsin dye using laccase-modified zeolite from aqueous solutions

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    This paper studies, the removal of acid fuchsin dye from aqueous solutions using zeolite natural material after its modification with laccase from Russulaceae (Lactarius volemus). Batch adsorption experiments were performed as a function of pH, contact time, temperature, and adsorbent dosage. The optimum results were obtained at pH 5, contact time of 60 min, temperature of 60ºC, and an adsorbent dosage of 1.5 mg/mL. The isotherm studies show that the adsorption experimental data are fitted well by Langmuir isotherm model. The adsorption capacity found is 31 mg/g. The kinetics of AFD adsorption on LMZ is best described with the pseudo-first-order kinetics model. Thermodynamic parameters including Gibbs free energy, enthalpy, and entropy changes indicate that the adsorption of Acid Fuchsin dye onto laccase-modified zeolite is feasible, spontaneous, and exothermic. The results show that laccase-modified zeolite can be used as an alternative lowcost adsorbent for dye removal from aqueous solutions. © 2015, HARD Publishing Company. All rights reserved
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