2,194 research outputs found
Isospin violation in via hadronic loops
In this work, we study the isospin-violating decay of
and quantify the electromagnetic (EM) transitions and intermediate meson
exchanges as two major sources of the decay mechanisms. In the EM decays, the
present datum status allows a good constraint on the EM decay form factor in
the vector meson dominance (VMD) model, and it turns out that the EM transition
can only account for about of the branching ratio for . The intermediate meson exchanges, (intermediate
interaction via exchanges), (intermediate
rescattering via kaon exchanges), and
(intermediate rescattering via exchanges), which evade the
naive Okubo-Zweig-Iizuka (OZI) rule, serve as another important contribution to
the isospin violations. They are evaluated with effective Lagrangians where
explicit constraints from experiment can be applied. Combining these three
contributions, we obtain results in good agreement with the experimental data.
This approach is also extended to , where
we find contributions from the , and
loops are negligibly small, and the isospin violation is
likely to be dominated by the EM transition.Comment: Revised version resubmitted to PRD; Additional loop contributions
included; Conclusion unchange
Intersite Coulomb repulsion driven quadrupole instability and magnetic ordering in the orbital frustrated BaMgReO
We develop an unrestricted Hartree-Fock mean-field method including Coulomb
repulsion U, V and spin-orbital coupling selfconsistently to
investigate the mechanism of structural instability and magnetic ordering in
BaMgReO. A comprehensive quadrupole phase diagram versus U and V with
=0.28eV is calculated. Our results demonstrate that, while U and
mainly lead to the onsite quadrupole and
with orbital frustration, the easy-plane anisotropy or the intersite Coulomb
repulsion V can remove the frustration. Finally, the V10meV would arrange
antiparallelly, accompanied with small parallel ,
and stabilize BaMgReO into the body centered tetragonal structure. Such
antiparallel provides a new mechanism of Dzyaloshinskii-Moriya
interaction, and gives rise to the canted antiferromagnetic (CAF) state along
[110] axis. Moreover, sizable octupoles such as , ,
and are discovered for the first time in CAF
states. Our study not only provides a comprehensive understanding of the nature
and exotic properties in BaMgReO, but also reveals some commonality of
5d compounds
Controlled Levofloxacin Release and Antibacterial Properties of Ξ²-Cyclodextrins-Grafted Polypropylene Mesh Devices for Hernia Repair.
Mesh infection is a major complication of hernia repair. After knitted mesh implantation, bacteria can grow within textile structures causing infection. In this work, polypropylene (PP) mesh devices were two-step grafted with hexamethylene diisocyanate (HDI) and Ξ²β»cyclodexrins (CD) and then loaded with suitable antimicrobial levofloxacin HCL for hernia mesh-infection prevention. First, oxygen plasma was able to create surface roughness, then HDI was successfully grafted onto PP fiber surfaces. Afterwards, CD was covalently grafted onto the HDI treated PP meshes, and levofloxacin HCL (LVFX) was loaded into the CD cavity of the modified meshes. The modified devices were evaluated for sustained antibiotic properties and drug-release profiles in a phosphate buffer, and sustained drug release was observed between interfaces of meshes and aqueous environment. The antibiotic-loaded PP mesh samples demonstrated sustained antibacterial properties for 7 and 10 days, respectively, against both Gram-negative and Gram-positive bacteria. The CD-captured levofloxacin HCL showed burst release after 6 h but later exhibited sustained release for the next 48 h. Among all samples, the modified mesh LVFX-6 was more stable and showed more sustained drug release and could be employed in future clinical applications
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