610 research outputs found
A combinatorial approach to metamaterials discovery
Some fifteen years ago a paper reporting a combinatorial approach to materials discoveries revolutionized materials research and other disciplines such as chemistry and pharmacology [1]. Here we report on how a combinatorial approach combined with advanced nanofabrication helps to discover photonic metamaterials optimized for prescribed functionalities
Three-dimensional conceptual model for service-oriented simulation
In this letter, we propose a novel three-dimensional conceptual model for an
emerging service-oriented simulation paradigm. The model can be used as a
guideline or an analytic means to find the potential and possible future
directions of the current simulation frameworks. In particular, the model
inspects the crossover between the disciplines of modeling and simulation,
service-orientation, and software/systems engineering. Finally, two specific
simulation frameworks are studied as examples.Comment: 7 pages, 1 figures, 3 table, Journal of Zhejiang University SCIENCE
A, 2009, 10(8): 1075-108
A combinatorial approach to metamaterials discovery
We report a high throughput combinatorial approach to photonic metamaterial optimization. The new approach is based on parallel synthesis and subsequent optical characterization of large numbers of spatially addressable nanofabricated metamaterial samples (libraries) with quasi-continuous variation of design parameters under real manufacturing conditions. We illustrate this method for Fano-resonance plasmonic nanostructures, arriving at explicit recipes for high quality factors needed for switching and sensing applications
A new type of optical activity in a toroidal metamaterial
We demonstrate experimentally and numerically the first ever observation of optical activity in a chiral metamaterial that is underpinned by the exotic resonant combination of an electric quadrupole and the elusive toroidal dipole
Toroidal circular dichroism
We demonstrate that the induced toroidal dipole, represented by currents flowing on the surface of a torus, makes a distinct and indispensable contribution to circular dichroism. We show that toroidal circular dichroism supplements the well-known mechanism involving electric dipole and magnetic dipole transitions. We illustrate this with rigorous analysis of the experimentally measured, polarization-sensitive transmission spectra of an artificial metamaterial, constructed from elements of toroidal symmetry. We argue that toroidal circular dichroism shall be found in large biomolecules with elements of toroidal symmetry and should be taken into account in the interpretation of circular dichroism spectra of organics
Tunable plasmonic luminescence in reconfigurable metamaterials
We show that new intense luminescence lines associated with transitions from collective plasmonic states below the Fermi level can be artificially created by metamaterial nanostructuring of plasmonic metals and tuned by nanoscale reconfiguration of metamaterial. We report on the experimental demonstration of a new radiation phenomenon on the nanoscale and its engineering into a reconfigurable metadevice: luminescence emission lines within the Fermi sea can be created by nanopatterning metal surfaces and controlled by external electrical inputs. Luminescence emission lines are associated with the decay of plasmonic excitation and are spectrally linked to the plasmonic absorption lines. Wavelength, polarization and intensity of metallic luminescence can be flexibly and independently adjusted by tweaking the geometric parameters of the metamaterial design similar to the way nanostructuring helps engineering semiconductor multiple quantum well and quantum dot luminescence
Probing For New Physics and Detecting non linear vacuum QED effects using gravitational wave interferometer antennas
Low energy non linear QED effects in vacuum have been predicted since 1936
and have been subject of research for many decades. Two main schemes have been
proposed for such a 'first' detection: measurements of ellipticity acquired by
a linearly polarized beam of light passing through a magnetic field and direct
light-light scattering. The study of the propagation of light through an
external field can also be used to probe for new physics such as the existence
of axion-like particles and millicharged particles. Their existence in nature
would cause the index of refraction of vacuum to be different from unity in the
presence of an external field and dependent of the polarization direction of
the light propagating. The major achievement of reaching the project
sensitivities in gravitational wave interferometers such as LIGO an VIRGO has
opened the possibility of using such instruments for the detection of QED
corrections in electrodynamics and for probing new physics at very low
energies. In this paper we discuss the difference between direct birefringence
measurements and index of refraction measurements. We propose an almost
parasitic implementation of an external magnetic field along the arms of the
VIRGO interferometer and discuss the advantage of this choice in comparison to
a previously proposed configuration based on shorter prototype interferometers
which we believe is inadequate. Considering the design sensitivity in the
strain, for the near future VIRGO+ interferometer, of in the range 40 Hz Hz leads to a variable
dipole magnet configuration at a frequency above 20 Hz such that Tm/ for a `first' vacuum non linear QED detection
Sorption properties of activated carbons obtained from corn cobs by chemical and physical activation
Transient Polycomb activity represses developmental genes in growing oocytes
Published online: 21 December 2022BACKGROUND: Non-genetic disease inheritance and offspring phenotype are substantially influenced by germline epigenetic programming, including genomic imprinting. Loss of Polycomb Repressive Complex 2 (PRC2) function in oocytes causes non-genetically inherited effects on offspring, including embryonic growth restriction followed by post-natal offspring overgrowth. While PRC2-dependent non-canonical imprinting is likely to contribute, less is known about germline epigenetic programming of non-imprinted genes during oocyte growth. In addition, de novo germline mutations in genes encoding PRC2 lead to overgrowth syndromes in human patients, but the extent to which PRC2 activity is conserved in human oocytes is poorly understood. RESULTS: In this study, we identify a discrete period of early oocyte growth during which PRC2 is expressed in mouse growing oocytes. Deletion of Eed during this window led to the de-repression of 343 genes. A high proportion of these were developmental regulators, and the vast majority were not imprinted genes. Many of the de-repressed genes were also marked by the PRC2-dependent epigenetic modification histone 3 lysine 27 trimethylation (H3K27me3) in primary-secondary mouse oocytes, at a time concurrent with PRC2 expression. In addition, we found H3K27me3 was also enriched on many of these genes by the germinal vesicle (GV) stage in human oocytes, strongly indicating that this PRC2 function is conserved in the human germline. However, while the 343 genes were de-repressed in mouse oocytes lacking EED, they were not de-repressed in pre-implantation embryos and lost H3K27me3 during pre-implantation development. This implies that H3K27me3 is a transient feature that represses a wide range of genes in oocytes. CONCLUSIONS: Together, these data indicate that EED has spatially and temporally distinct functions in the female germline to repress a wide range of developmentally important genes and that this activity is conserved in the mouse and human germlines.Ellen G. Jarred, Zhipeng Qu, Tesha Tsai, Ruby Oberin, Sigrid Petautschnig, Heidi Bildsoe, Stephen Pederson, Qing, hua Zhang, Jessica M. Stringer, John Carroll, David K. Gardner, Maarten Van den Buuse, Natalie A. Sims, William T. Gibson, David L. Adelson and Patrick S. Wester
Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at GeV
Identified mid-rapidity particle spectra of , , and
from 200 GeV p+p and d+Au collisions are reported. A
time-of-flight detector based on multi-gap resistive plate chamber technology
is used for particle identification. The particle-species dependence of the
Cronin effect is observed to be significantly smaller than that at lower
energies. The ratio of the nuclear modification factor () between
protons and charged hadrons () in the transverse momentum
range GeV/c is measured to be
(stat)(syst) in minimum-bias collisions and shows little
centrality dependence. The yield ratio of in minimum-bias d+Au
collisions is found to be a factor of 2 lower than that in Au+Au collisions,
indicating that the Cronin effect alone is not enough to account for the
relative baryon enhancement observed in heavy ion collisions at RHIC.Comment: 6 pages, 4 figures, 1 table. We extended the pion spectra from
transverse momentum 1.8 GeV/c to 3. GeV/
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