11,379 research outputs found

    An in-host model of HIV incorporating latent infection and viral mutation

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    We construct a seven-component model of the in-host dynamics of the Human Immunodeficiency Virus Type-1 (i.e, HIV) that accounts for latent infection and the propensity of viral mutation. A dynamical analysis is conducted and a theorem is presented which characterizes the long time behavior of the model. Finally, we study the effects of an antiretroviral drug and treatment implications.Comment: 10 pages, 7 figures, Proceedings of AIMS Conference on Differential Equations and Dynamical Systems (2015

    Preparation of productive and highly purified mogrosides from Siraitia grosvenorii

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    The mogrosides of Siraitia grosvenorii are natural sweetener and potential chemopreventive agents. In order to obtain high-yield and good-quality mogrosides, the flash extraction method was employed to extract mogrosides from S. grosvenorii. The extraction parameters were optimized by Taguchi’s experimental design, and the total yield of mogrosides was 8.6% under the optimum conditions. After purification by the chromatography column, the purity of mogrosides was greater than 92%. The separation technique described here may be applicable to commercial production of high-quality mogrosides.Key words: Flash extraction, mogrosides, mogroside V, purification, Taguchi’s experimental design

    Evolving small-world networks with geographical attachment preference

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    We introduce a minimal extended evolving model for small-world networks which is controlled by a parameter. In this model the network growth is determined by the attachment of new nodes to already existing nodes that are geographically close. We analyze several topological properties for our model both analytically and by numerical simulations. The resulting network shows some important characteristics of real-life networks such as the small-world effect and a high clustering.Comment: 11 pages, 4 figure

    High Dimensional Apollonian Networks

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    We propose a simple algorithm which produces high dimensional Apollonian networks with both small-world and scale-free characteristics. We derive analytical expressions for the degree distribution, the clustering coefficient and the diameter of the networks, which are determined by their dimension

    The development of ovary in quail’s embryo

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    The experiment was conducted to study the development of ovary in quails’ embryos which were incubated for 4 to 17 days and incubated out for 1 day. The quails’ embryos or gonads were cut out and HE staining was carried out. The results showed that when embryo was hatched for 4 days, lots of primordial germ cells (PGCs) clustered in the region where gonad would be formed. On the 5th day of hatching, the gonad of the embryo began to be formed and exhibited the feature of ovary or testis. On the 7th hatching day, the right ovary began to degenerate, just a few PGCs began to differentiate into oogonia. On the 10th day, there were many oogonia in the ovary, some of which were surrounded by some other cells distributed like circles. On the 11th day, there were more oogonia, the skinniness became thicker while the medulla was thinner. On the 13th day, the division between skinniness and medulla was obvious and the ovary formed the early original ovum. On the 14th day, more original ovums were seen in the skinniness. On the 17th hatching day and on the 1st day of hatching out, the shape of ovary tended to be mature, also the ovum was clear and more; the medulla was full of vessels. On the 5th hatching day, gonad began to differentiate. On the 7th hatching day and later, thedifferentiation of gonad was obvious; the right ovary began to degenerate. On the 13th hatching day, early original ovum began to be formed in the skinniness of ovary. The results established groundwork for the research of the development of gonads of quail and other poultry.Key words: Quail, embryo, gonad, ovary

    Generalized Misner-Sharp Energy in f(R) Gravity

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    We study generalized Misner-Sharp energy in f(R)f(R) gravity in a spherically symmetric spacetime. We find that unlike the cases of Einstein gravity and Gauss-Bonnet gravity, the existence of the generalized Misner-Sharp energy depends on a constraint condition in the f(R)f(R) gravity. When the constraint condition is satisfied, one can define a generalized Misner-Sharp energy, but it cannot always be written in an explicit quasi-local form. However, such a form can be obtained in a FRW universe and for static spherically symmetric solutions with constant scalar curvature. In the FRW universe, the generalized Misner-Sharp energy is nothing but the total matter energy inside a sphere with radius rr, which acts as the boundary of a finite region under consideration. The case of scalar-tensor gravity is also briefly discussed.Comment: Revtex, 17 pages, v2: some references added, to appear in PR

    Ricci Flat Black Holes and Hawking-Page Phase Transition in Gauss-Bonnet Gravity and Dilaton Gravity

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    It is well-known that there exists a Hawking-Page phase transition between a spherical AdS black hole and a thermal AdS space. The phase transition does not happen between a Ricci flat AdS black hole whose horizon is a Ricci flat space and a thermal AdS space in the Poincare coordinates. However, the Hawking-Page phase transition occurs between a Ricci flat AdS black hole and an AdS soliton if at least one of horizon coordinates for the Ricci flat black hole is compact. We show a similar phase transition betwen the Ricci flat black holes and deformed AdS solitons in the Gauss-Bonnet gravity and the dilaton gravity with a Liouville-type potential including the gauged supergravity coming from the spherical reduction of Dp-branes in type II supergravity. In contrast to Einstein gravity, we find that the high temperature phase can be dominated either by black holes or deformed AdS solitons depending on parameters.Comment: Latex, 17 pages without figure

    Compensation effect analysis in DIE method for through-casing measuring formation resistivity

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    The measuring technique based on Double-Injection-Electrodes (DIE) and its compensation arithmetic method have been proven to be very useful for eliminating the errors caused by electrode-scale mechanical tolerances in formation resistivity measurement through metal case. In this paper, we found that even minor casing joint or casing corrosion may deteriorate the measurement accuracy. Based on theoretical analysis and self-adaptive goal oriented hp-Finite Element (FE) simulations, the compensation effects of DIE measurement technique were estimated. The calculated results from this measuring method are always close to the real formation resistivity, regardless of whether the metal casing is ideal or not. Meanwhile, large errors occur when recording measurements based on Single-Injection-Electrodes (SIE), since the calculated formation resistivity may provide negative values when casing joint or casing corrosion exists. The Double-Injection-Electrode (DIE) measurement technique is predicted to have good compensation effects in many non-ideal situations with uneven metal casing besides electrode-scale mechanical tolerances.MTM2010 1651

    Solving the subset-sum problem with a light-based device

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    We propose a special computational device which uses light rays for solving the subset-sum problem. The device has a graph-like representation and the light is traversing it by following the routes given by the connections between nodes. The nodes are connected by arcs in a special way which lets us to generate all possible subsets of the given set. To each arc we assign either a number from the given set or a predefined constant. When the light is passing through an arc it is delayed by the amount of time indicated by the number placed in that arc. At the destination node we will check if there is a ray whose total delay is equal to the target value of the subset sum problem (plus some constants).Comment: 14 pages, 6 figures, Natural Computing, 200

    Phonon-assisted Kondo Effect in a Single-Molecule Transistor out of Equilibrium

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    The joint effect of the electron-phonon interaction and Kondo effect on the nonequilibrium transport through the single molecule transistor is investigated by using the improved canonical transformation scheme and extended equation of motion approach. Two types of Kondo phonon-satellites with different asymmetric shapes are fully confirmed in the spectral function, and are related to the electron spin singlet or hole spin singlet, respectively. Moreover, when a moderate Zeeman splitting is caused by a local magnetic field, the Kondo satellites in the spin resolved spectral function are found disappeared on one side of the main peak, which is opposite for different spin component. All these peculiar signatures that manifest themselves in the nonlinear differential conductance, are explained with a clear physics picture.Comment: 12 pages, 6 figure
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