1,250 research outputs found
Possible S-wave Dibaryons in SU(3) Chiral Quark Model
In the framework of the SU(3) chiral quark model, the wave baryon-baryon
bound states are investigated. It is found that according to the symmetry
character of the system and the contributions from chiral fields, there are
three types of bound states. The states of the first type, such as
and are deeply bound
dibaryon with narrow widths. The second type states, ,,
and are also bound states, but with broad widths.
, , and are third type states. They, like {\em d}, are weakly bound
only if the chiral fields can provide attraction between baryons.Comment: Latex files, 1 figur
Electrodeposition of Ni-Si Schottky barriers
Electrodeposition is being used to fabricate magnetic microstructures directly on patterned n-type Si wafers of various substrate resistivities. The Ni-Si Schottky barrier is characterized and found to be of high quality for relatively low Si resistivities (1-2 Omega(.)cm), with extremely low reverse leakage. It is shown that a direct correlation exists among the electrodeposition potential, the roughness, and the coercivity of the films. A conductive seed layer or a back contact is not compulsory for electrodeposition on Si with resistivities up to 15 Omega(.)cm. This shows that electrodeposition of magnetic materials on Si might be a viable fabrication technique for magnetoresistance and spintronics applications
Laminin and Heparan Sulfate Proteoglycan Mediate Epithelial Cell Polarization in Organotypic Cultures of Embryonic Lung Cells: Evidence Implicating Involvement of the Inner Globular Region of Laminin β 1 Chain and the Heparan Sulfate Groups of Heparan Sulfate Proteoglycan
AbstractThe extracellular matrix and in particular the basement membrane (BM) play an important role in the induction of organotypic rearrangement of cells in culture. This process involves cell aggregation, sorting into epithelial and mesenchymal components, epithelial cell polarization, and lumen formation. In this study, a combination of laminin (LM) and heparan sulfate proteoglycan (HSPG), two major BM constituents, induced organotypic rearrangement of embryonic mouse lung cells. In the absence of LM/HSPG supplementation, the cells sorted into epithelial and mesenchymal compartments but epithelial cell polarization and lumen formation did not occur. Neither LM nor HSPG alone could trigger this process. Synthetic peptide F-9, representing an amino acid sequence from the inner globular region of the laminin β1 chain (RYVVLPRPVCFEKGMNYTVR) induced organotypic cell rearrangement when substituted for LM. Exogenous LM as well as peptide F-9 were localized at the epithelial–mesenchymal interface of organotypic cultures, where a BM-like structure is formedde novo.Organotypic cell rearrangement was blocked by heparin, heparan sulfate, or antibodies against peptide F-9. Binding assays indicated that peptide F-9 interacts with HSPG but not with LM or type IV collagen. Preincubation of embryonic lung cells with peptide F-9 resulted in a significant increase in cell attachment to HSPG but not to other major BM constituents. These findings suggest that the interaction between LM and BM HSPG is critical for the development of epithelial cell polarization and lumen formation. This interaction occurs at the epithelial–mesenchymal interface and is mediated by a site in the LM molecule represented by peptide F-9 and the heparan sulfate groups of HSPG
Shape-induced anisotropy in antidot arrays from self-assembled templates
Using self-assembly of polystyrene spheres, well-ordered templates have been prepared on glass and silicon substrates. Strong guiding of self-assembly is obtained on photolithographically structured silicon substrates. Magnetic antidot arrays with three-dimensional architecture have been prepared by electrodeposition in the pores of these templates. The shape anisotropy demonstrates a crucial impact on magnetization reversal processes
Possible Dibaryons with Strangeness s=-5
In the framework of , the binding energy of the six quark system with
strangeness s=-5 is systematically investigated under the SU(3) chiral
constituent quark model. The single channel calculation with
spins S=0 and 3 and the coupled and channel
calculation with spins S=1 and 2 are considered, respectively. The results show
following observations: In the spin=0 case, is a bound dibaryon
with the binding energy being . In the S=1 case,
is also a bound dibaryon. Its binding energy is ranged from to . In the S=2 and S=3 cases, no evidence of bound dibaryons
are found. The phase shifts and scattering lengths in the S=0 and S=1 cases are
also given.Comment: 10 pages, late
Electrothermal Icing Protection of Aerosurfaces Using Conductive Polymer Nanocomposites
Ice protection systems (IPS) are critical components for many aerospace flight vehicles, including commercial transports and unmanned aerial systems (UAS), and can include anti-icing, de-icing, ice sensing, etc. Here, an IPS is created using nanomaterials to create a surface-modified external layer on an aerosurface based on observations that polymer nanocomposites have tailorable and attractive heating properties. The IPS uses Joule heating of aligned carbon nanotube (CNT) arrays to create highly efficient de-icing and anti-icing of aerosurfaces. An ice wind tunnel test of a CNT enhanced aerosurface is performed to demonstrate the system under a range of operating regimes (temperature, wind speed, water content in air) including operation down to -20.6°C (-5°F) at 55.9 m/s (125 mph) under heavy icing. Manufacturing, design considerations, and further improvements to the materials and systems are discussed.United States. Dept. of the Navy. Small Business Innovation Research (Contract N68335-11-C-0424)National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (Grant DMR-0819762
Nonperturbative Corrections to One Gluon Exchange Quark Potentials
The leading nonperturbative QCD corrections to the one gluon exchange
quark-quark, quark-antiquark and pair-excitation potentials are
derived by using a covariant form of nonlocal two-quark and two-gluon vacuum
expectation values. Our numerical calculation indicates that the correction of
quark and gluon condensates to the quark-antiquark potential improves the heavy
quarkonium spectra to some degree.Comment: LaTex, 16 pages, three figures, to appear in Nucl. Phys.
Genome-wide association study for Atopy and Allergic Rhinitis in a Singapore Chinese population
10.1371/journal.pone.0019719PLoS ONE65
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