10,117 research outputs found
Collective cell migration: Implications for wound healing and cancer invasion.
During embryonic morphogenesis, wound repair and cancer invasion, cells often migrate collectively via tight cell-cell junctions, a process named collective migration. During such migration, cells move as coherent groups, large cell sheets, strands or tubes rather than individually. One unexpected finding regarding collective cell migration is that being a "multicellular structure" enables cells to better respond to chemical and physical cues, when compared with isolated cells. This is important because epithelial cells heal wounds via the migration of large sheets of cells with tight intercellular connections. Recent studies have gained some mechanistic insights that will benefit the clinical understanding of wound healing in general. In this review, we will briefly introduce the role of collective cell migration in wound healing, regeneration and cancer invasion and discuss its underlying mechanisms as well as implications for wound healing
Actively controlling the topological transition of dispersion based on electrically controllable metamaterials
Topological transition of the iso-frequency contour (IFC) from a closed
ellipsoid to an open hyperboloid, will provide unique capabilities for
controlling the propagation of light. However, the ability to actively tune
these effects remains elusive and the related experimental observations are
highly desirable. Here, tunable electric IFC in periodic structure which is
composed of graphene/dielectric multilayers is investigated by tuning the
chemical potential of graphene layer. Specially, we present the actively
controlled transportation in two kinds of anisotropic zero-index media
containing PEC/PMC impurities. At last, by adding variable capacitance diodes
into two-dimensional transmission-line system, we present the experimental
demonstration of the actively controlled magnetic topological transition of
dispersion based on electrically controllable metamaterials. With the increase
of voltage, we measure the different emission patterns from a point source
inside the structure and observe the phase-transition process of IFCs. The
realization of actively tuned topological transition will opens up a new avenue
in the dynamical control of metamaterials.Comment: 21 pages,8 figure
Top Hypercharge
We propose a top hypercharge model with gauge symmetry SU(3)_C x SU(2)_L x
U(1)_1 x U(1)_2 where the first two families of the Standard Model (SM)
fermions are charged under U(1)_1 while the third family is charged under
U(1)_2. The U(1)_1 x U(1)_2 gauge symmetry is broken down to the U(1)_Y gauge
symmetry, when a SM singlet Higgs field acquires a vacuum expectation value. We
consider the electroweak constraints, and compare the fit to experimental
observables to that of the SM. We study the quark CKM mixing between the first
two families and the third family, the neutrino masses and mixing, the flavour
changing neutral current effects in meson mixing and decays, the Z' discovery
potential at the Large Hadron Collider, the dark matter with a gauged Z_2
symmetry, and the Higgs boson masses.Comment: 17 pages and 4 figure
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