8,086 research outputs found
Enhancement of Recombinant Protein Production in Transgenic Nicotiana benthamiana Plant Cell Suspension Cultures with Co-Cultivation of Agrobacterium Containing Silencing Suppressors.
We have previously demonstrated that the inducible plant viral vector (CMViva) in transgenic plant cell cultures can significantly improve the productivity of extracellular functional recombinant human alpha-1-antiryspin (rAAT) compared with either a common plant constitutive promoter (Cauliflower mosaic virus (CaMV) 35S) or a chemically inducible promoter (estrogen receptor-based XVE) system. For a transgenic plant host system, however, viral or transgene-induced post-transcriptional gene silencing (PTGS) has been identified as a host response mechanism that may dramatically reduce the expression of a foreign gene. Previous studies have suggested that viral gene silencing suppressors encoded by a virus can block or interfere with the pathways of transgene-induced PTGS in plant cells. In this study, the capability of nine different viral gene silencing suppressors were evaluated for improving the production of rAAT protein in transgenic plant cell cultures (CMViva, XVE or 35S system) using an Agrobacterium-mediated transient expression co-cultivation process in which transgenic plant cells and recombinant Agrobacterium carrying the viral gene silencing suppressor were grown together in suspension cultures. Through the co-cultivation process, the impacts of gene silencing suppressors on the rAAT production were elucidated, and promising gene silencing suppressors were identified. Furthermore, the combinations of gene silencing suppressors were optimized using design of experiments methodology. The results have shown that in transgenic CMViva cell cultures, the functional rAAT as a percentage of total soluble protein is increased 5.7 fold with the expression of P19, and 17.2 fold with the co-expression of CP, P19 and P24
The scalars from the topcolor scenario and the spin correlations of the top pair production at the LHC
The topcolor scenario predicts the existences of some new scalars. In this
paper, we consider the contributions of these new particles to the observables,
which are related to the top quark pair () production at the LHC. It
is found that these new particles can generate significant corrections to the
production cross section and the spin correlations.Comment: 23 pages, 4 figures; discussions and references added; agrees with
published versio
Technique of quantum state transfer for a double Lambda atomic beam
The transfer technique of quantum states from light to collective atomic
excitations in a double type system is extended to matter waves in
this paper, as a novel scheme towards making a continuous atom laser. The
intensity of the output matter waves is found to be determined by the initial
relative phase of the two independent coherent probe lights, which may indicate
an interesting method for the measurement of initial relative phase of two
independent light sources.Comment: 5 pages, 2 figure
Finite-Time Disentanglement via Spontaneous Emission
We show that under the influence of pure vacuum noise two entangled qubits
become completely disentangled in a finite time, and in a specific example we
find the time to be given by times the
usual spontaneous lifetime.Comment: revtex, 4 pages, 2 figure
Elastodynamics of radially inhomogeneous spherically anisotropic elastic materials in the Stroh formalism
A method is presented for solving elastodynamic problems in radially
inhomogeneous elastic materials with spherical anisotropy, i.e.\ materials such
that in a spherical coordinate system
. The time harmonic displacement field is expanded in a separation of variables form with dependence on
described by vector spherical harmonics with -dependent
amplitudes. It is proved that such separation of variables solution is
generally possible only if the spherical anisotropy is restricted to transverse
isotropy with the principal axis in the radial direction, in which case the
amplitudes are determined by a first-order ordinary differential system.
Restricted forms of the displacement field, such as ,
admit this type of separation of variables solutions for certain lower material
symmetries. These results extend the Stroh formalism of elastodynamics in
rectangular and cylindrical systems to spherical coordinates.Comment: 15 page
Experimental verification of a self-consistent theory of the first-, second-, and third-order (non)linear optical response
We show that a combination of linear absorption spectroscopy, hyper-Rayleigh
scattering, and a theoretical analysis using sum rules to reduce the size of
the parameter space leads to a prediction of the two-photon absorption
cross-section of the dye AF455 that agrees with two-photon absorption
spectroscopy. Our procedure, which demands self-consistency between several
measurement techniques and does not use adjustable parameters, provides a means
for determining transition moments between the dominant excited states based
strictly on experimental characterization. This is made possible by our new
approach that uses sum rules and molecular symmetry to rigorously reduce the
number of required physical quantities.Comment: 10 pages, 9 figure
A Linux PC cluster for lattice QCD with exact chiral symmetry
A computational system for lattice QCD with exact chiral symmetry is
described. The platform is a home-made Linux PC cluster, built with
off-the-shelf components. At present this system constitutes of 64 nodes, with
each node consisting of one Pentium 4 processor (1.6/2.0/2.5 GHz), one Gbyte of
PC800/PC1066 RDRAM, one 40/80/120 Gbyte hard disk, and a network card. The
computationally intensive parts of our program are written in SSE2 codes. The
speed of this system is estimated to be 70 Gflops, and its price/performance is
better than $1.0/Mflops for 64-bit (double precision) computations in quenched
QCD. We discuss how to optimize its hardware and software for computing quark
propagators via the overlap Dirac operator.Comment: 24 pages, LaTeX, 2 eps figures, v2:a note and references added, the
version published in Int. J. Mod. Phys.
Simultaneous X-ray and Ultraviolet Observations of the SW Sextantis Star DW Ursae Majoris
We present the first pointed X-ray observation of DW Ursae Majoris, a novalike cataclysmic variable (CV) and one of the archetype members of the SW Sextantis class, obtained with the XMM-Newton satellite. These data provide the first detailed look at an SW Sex star in the X-ray regime (with previous X-ray knowledge of the SW Sex stars limited primarily to weak or non-detections in the ROSAT All Sky Survey). It is also one of only a few XMM-Newton observations (to date) of any high mass transfer rate novalike CV, and the only one in the evolutionarily important 3-4 hr orbital period range. The observed X-ray spectrum of DW UMa is very soft, with ~95% of the detected X-ray photons at energies <2 keV. The spectrum can be fit equally well by a one-component cooling flow model, with a temperature range of 0.2-3.5 keV, or a two-component, two-temperature thermal plasma model, containing hard (~5-6 keV) and soft (~0.8 keV) components. The X-ray light curve of DW UMa shows a likely partial eclipse, implying X-ray reprocessing in a vertically extended region, and an orbital modulation, implying a structural asymmetry in the X-ray reprocessing site (e.g., it cannot be a uniform corona). We also obtained a simultaneous near-ultraviolet light curve of DW UMa using the Optical Monitor on XMM-Newton. This light curve is similar in appearance to published optical-UV light curves of DW UMa and shows a prominent deep eclipse. Regardless of the exact nature of the X-ray reprocessing site in DW UMa, the lack of a prominent hard X-ray total eclipse and very low fraction of high energy X-rays point to the presence of an optically and geometrically thick accretion disk that obscures the boundary layer and modifies the X-ray spectrum emitted near the white dwarf
A survey of cost-sensitive decision tree induction algorithms
The past decade has seen a significant interest on the problem of inducing decision trees that take account of costs of misclassification and costs of acquiring the features used for decision making. This survey identifies over 50 algorithms including approaches that are direct adaptations of accuracy based methods, use genetic algorithms, use anytime methods and utilize boosting and bagging. The survey brings together these different studies and novel approaches to cost-sensitive decision tree learning, provides a useful taxonomy, a historical timeline of how the field has developed and should provide a useful reference point for future research in this field
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