10,772 research outputs found
Nanoscale magnetophotonics
This Perspective surveys the state-of-the-art and future prospects of science
and technology employing the nanoconfined light (nanophotonics and
nanoplasmonics) in combination with magnetism. We denote this field broadly as
nanoscale magnetophotonics. We include a general introduction to the field and
describe the emerging magneto-optical effects in magnetoplasmonic and
magnetophotonic nanostructures supporting localized and propagating plasmons.
Special attention is given to magnetoplasmonic crystals with transverse
magnetization and the associated nanophotonic non-reciprocal effects, and to
magneto-optical effects in periodic arrays of nanostructures. We give also an
overview of the applications of these systems in biological and chemical
sensing, as well as in light polarization and phase control. We further review
the area of nonlinear magnetophotonics, the semiconductor spin-plasmonics, and
the general principles and applications of opto-magnetism and nano-optical
ultrafast control of magnetism and spintronics
Spatial and spatiotemporal variation in metapopulation structure affects population dynamics in a passively dispersing arthropod
The spatial and temporal variation in the availability of suitable habitat within metapopulations determines colonization-extinction events, regulates local population sizes and eventually affects local population and metapopulation stability. Insights into the impact of such a spatiotemporal variation on the local population and metapopulation dynamics are principally derived from classical metapopulation theory and have not been experimentally validated. By manipulating spatial structure in artificial metapopulations of the spider mite Tetranychus urticae, we test to which degree spatial (mainland-island metapopulations) and spatiotemporal variation (classical metapopulations) in habitat availability affects the dynamics of the metapopulations relative to systems where habitat is constantly available in time and space (patchy metapopulations). Our experiment demonstrates that (i) spatial variation in habitat availability decreases variance in metapopulation size and decreases density-dependent dispersal at the metapopulation level, while (ii) spatiotemporal variation in habitat availability increases patch extinction rates, decreases local population and metapopulation sizes and decreases density dependence in population growth rates. We found dispersal to be negatively density dependent and overall low in the spatial variable mainland-island metapopulation. This demographic variation subsequently impacts local and regional population dynamics and determines patterns of metapopulation stability. Both local and metapopulation-level variabilities are minimized in mainland-island metapopulations relative to classical and patchy ones
Bionanomedicine: A “Panacea” In Medicine?
Recent advances in nanotechnology, biotechnology, bioinformatics, and materials science have prompted novel developments in the field of nanomedicine. Enhancements in the theranostics, computational information, and management of diseases/disorders are desperately required. It may now be conceivable to accomplish checked improvements in both of these areas utilising nanomedicine. This scientific and concise review concentrates on the fundamentals and potential of nanomedicine, particularly nanoparticles and their advantages, nanoparticles for siRNA conveyance, nanopores, nanodots, nanotheragnostics, nanodrugs and targeting mechanisms, and aptamer nanomedicine. The combination of various scientific fields is quickening these improvements, and these interdisciplinary endeavours to have significant progressively outstretching influences on different fields of research. The capacities of nanomedicine are immense, and nanotechnology could give medicine a completely new standpoint
Nanoantennas for visible and infrared radiation
Nanoantennas for visible and infrared radiation can strongly enhance the
interaction of light with nanoscale matter by their ability to efficiently link
propagating and spatially localized optical fields. This ability unlocks an
enormous potential for applications ranging from nanoscale optical microscopy
and spectroscopy over solar energy conversion, integrated optical
nanocircuitry, opto-electronics and density-ofstates engineering to
ultra-sensing as well as enhancement of optical nonlinearities. Here we review
the current understanding of optical antennas based on the background of both
well-developed radiowave antenna engineering and the emerging field of
plasmonics. In particular, we address the plasmonic behavior that emerges due
to the very high optical frequencies involved and the limitations in the choice
of antenna materials and geometrical parameters imposed by nanofabrication.
Finally, we give a brief account of the current status of the field and the
major established and emerging lines of investigation in this vivid area of
research.Comment: Review article with 76 pages, 21 figure
Reorientation kinetics of superparamagnetic nanostructured rods
The attractive interactions between oppositely charged species (colloids,
macromolecules etc) dispersed in water are strong, and the direct mixing of
solutions containing such species generally yields to a precipitation, or to a
phase separation. We have recently developed means to control the
electrostatically-driven attractions between nanoparticles and polymers in
water, and at the same time to preserve the stability of the dispersions. We
give here an account of the formation of supracolloidal aggregates obtained by
co-assembly of 7 nm particles with copolymers. Nanostructured rods of length
comprised between 5 and 50 microns and diameter 500 nm were investigated. By
application of a magnetic field, the rods were found to reorient along with the
magnetic field lines. The kinetics of reorientation was investigated using step
changes of the magnetic field of amplitude 90 degrees. From the various results
obtained, among which an exponential decay of the tangent of the angle made
between the rod and the field, we concluded that the rods are
superparamagnetic.Comment: 12 pages - 452kB 7 - figures - 1 Table will be published in Journal
of Physics : Condensed Matte
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