Computational electromagnetic solutions for large-scale conductors, left-handed metamaterials and plasmonic nanostructures

2011 ◽  
Author(s):  
F. Obelleiro ◽  
J. M. Taboada ◽  
M. G. Araujo ◽  
L. Landesa
Keyword(s):  
Large Scale ◽  
Plasmonic Nanostructures ◽  
Left Handed

Microsurgically generated discontinuities provoke heritable changes in cellular handedness of a ciliate, Stylonychia mytilus

Development ◽  
1991 ◽  
Vol 111 (2) ◽  
pp. 337-356
Author(s):  
X.B. Shi ◽  
Z.I. Qiu ◽  
W. He ◽  
J. Frankel
Keyword(s):  
Large Scale ◽  
Mirror Image ◽  
The Other ◽  
Left Edge ◽  
Left Handed ◽  
Specific Manner ◽  
The Right ◽  
Anteroposterior Polarity ◽  
Posterior Anterior ◽  
Stylonychia Mytilus

Stylonychia mytilus is a dorsoventrally flattened ciliate with compound ciliary structures arranged in a specific manner on the cell surface. In mirror-image (MI) doublets of this ciliate, two nearly complete sets of ciliary structures are arrayed side-by-side, one in a normal or ‘right-handed’ (RH) arrangement, the other in a reversed or ‘left-handed’ (LH) arrangement. MI-doublets exist in two forms, one with the RH component on the right, the LH component on the left, and feeding structures near the center (‘buccal-adjoining MI-doublet’); the other with the RH component on the left, the LH component on the right, and feeding structures on the lateral edges (‘buccal-opposing MI-doublet’). We describe an operation that can generate either type of MI-doublet. This operation interchanges large anterior and posterior regions of the cell, transposing the original posterior region anteriorly (P—A) and the original anterior region posteriorly (A—P), while retaining the original anteroposterior polarity of each region. Two sets of new ciliary structures then are formed in mirror-image arrangement, with the set in the P—A region oriented normally and the set in the A—P region undergoing a reversal of polarity along its anteroposterior axis. This sometimes creates end-to-end MI forms, but more commonly produces side-by-side MI-doublets through a folding together of the P—A and A—P regions. This folding occurs because one lateral edge of the cell had been removed during the operation; if the left edge was removed, the complex folds to the left and forms a buccal-adjoining MI-doublet, whereas if the right edge was removed, the complex folds to the right and forms a buccal-opposing MI-doublet. Both types can reorganize and later divide true-to-type, although the ‘buccal-opposing’ type is by far the more stable of the two. The generation of mirror-image forms is dependent on the prior abnormal juxtaposition of regions from opposite ends of the cell, and involves a coordinated respecification of large-scale organization. We interpret this response to be a consequence of intercalation of missing intervening positional values in the zone of posterior-anterior abutment.

scholarly journals Is there a left-handed magnetic field in the solar neighborhood?

2019 ◽  
Vol 621 ◽  
pp. A97 ◽  
Author(s):  
A. Bracco ◽  
S. Candelaresi ◽  
F. Del Sordo ◽  
A. Brandenburg
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Large Scale ◽  
Power Spectra ◽  
Field Structure ◽  
Solar Neighborhood ◽  
Galactic Magnetic Field ◽  
Polarization Data ◽  
Left Handed ◽  
Cross Correlations

Context. The analysis of the full-sky Planck polarization data at 850 μm revealed unexpected properties of the E- and B-mode power spectra of dust emission in the interstellar medium (ISM). The positive cross-correlations over a wide range of angular scales between the total dust intensity, T, and both E and (most of all) B modes has raised new questions about the physical mechanisms that affect dust polarization, such as the Galactic magnetic field structure. This is key both to better understanding ISM dynamics and to accurately describing Galactic foregrounds to the polarization of the cosmic microwave background (CMB). In particular, in the quest to find primordial B modes of the CMB, the observed positive cross-correlation between T and B for interstellar dust requires further investigation towards parity-violating processes in the ISM. Aims. In this theoretical paper we investigate the possibility that the observed cross-correlations in the dust polarization power spectra, and specifically the one between T and B, can be related to a parity-odd quantity in the ISM such as the magnetic helicity. Methods. We produce synthetic dust polarization data, derived from 3D analytical toy models of density structures and helical magnetic fields, to compare with the E and B modes of observations. We present several models. The first is an ideal fully helical isotropic case, such as the Arnold-Beltrami-Childress field. Second, following the nowadays favored interpretation of the T–E signal in terms of the observed alignment between the magnetic field morphology and the filamentary density structure of the diffuse ISM, we design models for helical magnetic fields wrapped around cylindrical interstellar filaments. Lastly, focusing on the observed T–B correlation, we propose a new line of interpretation of the Planck observations advocating the presence of a large-scale helical component of the Galactic magnetic field in the solar neighborhood. Results. Our analysis shows that: I) the sign of magnetic helicity does not affect E and B modes for isotropic magnetic-field configurations; II) helical magnetic fields threading interstellar filaments cannot reproduce the Planck results; and III) a weak helical left-handed magnetic field structure in the solar neighborhood may explain the T–B correlation seen in the Planck data. Such a magnetic-field configuration would also account for the observed large-scale T–E correlation. Conclusions. This work suggests a new perspective for the interpretation of the dust polarization power spectra that supports the imprint of a large-scale structure of the Galactic magnetic field in the solar neighborhood.

scholarly journals Localized Surface Plasmons Enhanced Light Transmission into c-Silicon Solar Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Y. Premkumar Singh ◽  
Amit Jain ◽  
Avinashi Kapoor
Keyword(s):  
Solar Cells ◽  
Metallic Nanoparticles ◽  
Large Scale ◽  
Light Transmission ◽  
Low Cost ◽  
Incident Light ◽  
Solar Spectrum ◽  
Localized Surface Plasmon ◽  
Plasmonic Nanostructures ◽  
Al Nanoparticles

The paper investigates the light incoupling into c-Si solar cells due to the excitation of localized surface plasmon resonances in periodic metallic nanoparticles by finite-difference time-domain (FDTD) technique. A significant enhancement of AM1.5G solar radiation transmission has been demonstrated by depositing nanoparticles of various metals on the upper surface of a semi-infinite Si substrate. Plasmonic nanostructures located close to the cell surface can scatter incident light efficiently into the cell. Al nanoparticles were found to be superior to Ag, Cu, and Au nanoparticles due to the improved transmission of light over almost the entire solar spectrum and, thus, can be a potential low-cost plasmonic metal for large-scale implementation of solar cells.

scholarly journals Large-scale dynamic assembly of metal nanostructures in plasmofluidic field

2016 ◽  
Vol 186 ◽  
pp. 95-106 ◽  
Author(s):  
Partha Pratim Patra ◽  
Rohit Chikkaraddy ◽  
Sreeja Thampi ◽  
Ravi P. N. Tripathi ◽  
G. V. Pavan Kumar
Keyword(s):  
Evanescent Wave ◽  
Large Scale ◽  
Metal Nanostructures ◽  
Plasmonic Nanostructures ◽  
Wave Excitation ◽  
Fluid Interface ◽  
Test Bed ◽  
Ag Nanowires ◽  
Dynamic Assembly ◽  
Evanescent Wave Excitation

We discuss two aspects of the plasmofluidic assembly of plasmonic nanostructures at the metal–fluid interface. First, we experimentally show how three and four spot evanescent-wave excitation can lead to unconventional assembly of plasmonic nanoparticles at the metal–fluid interface. We observed that the pattern of assembly was mainly governed by the plasmon interference pattern at the metal–fluid interface, and further led to interesting dynamic effects within the assembly. The interference patterns were corroborated by 3D finite-difference time-domain simulations. Secondly, we show how anisotropic geometry, such as Ag nanowires, can be assembled and aligned in unstructured and structured plasmofluidic fields. We found that by structuring the metal-film, Ag nanowires can be aligned at the metal–fluid interface with a single evanescent-wave excitation, thus highlighting the prospect of assembling plasmonic circuits in a fluid. An interesting aspect of our method is that we obtain the assembly at locations away from the excitation points, thus leading to remote assembly of nanostructures. The results discussed herein may have implications in realizing a platform for reconfigurable plasmonic metamaterials, and a test-bed to understand the effect of plasmon interference on assembly of nanostructures in fluids.

scholarly journals A large-scale estimate on the relationship between language and motor lateralization

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Julian Packheiser ◽  
Judith Schmitz ◽  
Larissa Arning ◽  
Christian Beste ◽  
Onur Güntürkün ◽  
...  
Keyword(s):  
Language Processing ◽  
Dichotic Listening ◽  
Large Scale ◽  
Accurate Estimate ◽  
Language Lateralization ◽  
Left Handed ◽  
Right Ear Advantage ◽  
Motor Asymmetries ◽  
Continuous Measures ◽  
Scale Estimate

AbstractHuman language is dominantly processed in the left cerebral hemisphere in most of the population. While several studies have suggested that there are higher rates of atypical right-hemispheric language lateralization in left-/mixed-handers, an accurate estimate of this association from a large sample is still missing. In this study, we comprised data from 1,554 individuals sampled in three previous studies in which language lateralization measured via dichotic listening, handedness and footedness were assessed. Overall, we found a right ear advantage indicating typical left-hemispheric language lateralization in 82.1% of the participants. While we found significantly more left-handed individuals with atypical language lateralization on the categorical level, we only detected a very weak positive correlation between dichotic listening lateralization quotients (LQs) and handedness LQs using continuous measures. Here, only 0.4% of the variance in language lateralization were explained by handedness. We complemented these analyses with Bayesian statistics and found no evidence in favor of the hypothesis that language lateralization and handedness are related. Footedness LQs were not correlated with dichotic listening LQs, but individuals with atypical language lateralization also exhibited higher rates of atypical footedness on the categorical level. We also found differences in the extent of language lateralization between males and females with males exhibiting higher dichotic listening LQs indicating more left-hemispheric language processing. Overall, these findings indicate that the direct associations between language lateralization and motor asymmetries are much weaker than previously assumed with Bayesian correlation analyses even suggesting that they do not exist at all. Furthermore, sex differences seem to be present in language lateralization when the power of the study is adequate suggesting that endocrinological processes might influence this phenotype.

scholarly journals Large scale self-assembly of plasmonic nanoparticles on deformed graphene templates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matthew T. Gole ◽  
Zhewen Yin ◽  
Michael Cai Wang ◽  
Wayne Lin ◽  
Ziran Zhou ◽  
...  
Keyword(s):  
Self Assembly ◽  
Polymer Brushes ◽  
Large Scale ◽  
2D Materials ◽  
Plasmonic Nanoparticles ◽  
Plasmonic Nanostructures ◽  
Plasmonic Coupling ◽  
Lithographic Patterning ◽  
Assembly Method ◽  
2D Nanomaterials

AbstractHierarchical heterostructures of two-dimensional (2D) nanomaterials are versatile platforms for nanoscale optoelectronics. Further coupling of these 2D materials with plasmonic nanostructures, especially in non-close-packed morphologies, imparts new metastructural properties such as increased photosensitivity as well as spectral selectivity and range. However, the integration of plasmonic nanoparticles with 2D materials has largely been limited to lithographic patterning and/or undefined deposition of metallic structures. Here we show that colloidally synthesized zero-dimensional (0D) gold nanoparticles of various sizes can be deterministically self-assembled in highly-ordered, anisotropic, non-close-packed, multi-scale morphologies with templates designed from instability-driven, deformed 2D nanomaterials. The anisotropic plasmonic coupling of the particle arrays exhibits emergent polarization-dependent absorbance in the visible to near-IR regions. Additionally, controllable metasurface arrays of nanoparticles by functionalization with varying polymer brushes modulate the plasmonic coupling between polarization dependent and independent assemblies. This self-assembly method shows potential for bottom-up nanomanufacturing of diverse optoelectronic components and can potentially be adapted to a wide array of nanoscale 0D, 1D, and 2D materials.

scholarly journals Large area metasurfaces made with spherical silicon resonators

Nanophotonics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 943-951
Author(s):  
Pau Molet ◽  
Luz Karimé Gil-Herrera ◽  
Juan Luis Garcia-Pomar ◽  
Niccolò Caselli ◽  
Álvaro Blanco ◽  
...  
Keyword(s):  
Large Scale ◽  
Light Emission ◽  
Low Cost ◽  
Chemical Vapor ◽  
High Refractive Index ◽  
Dielectric Substrate ◽  
Design Parameters ◽  
Plasmonic Nanostructures ◽  
Large Area ◽  
Silicon Resonators

AbstractHigh-index dielectric nanostructures have emerged as an appealing complement to plasmonic nanostructures, offering similar light management capabilities at the nanoscale but free from the inherent optical losses. Despite the great interest in these all-dielectric architectures, their fabrication still requires cumbersome fabrication techniques that limit their implementation in many applications. Hence, the great interest in alternative scalable procedures. Among those, the fabrication of silicon spheres is at the forefront, with several routes available in the literature. However, the exploitation of the Mie modes sustained by these silicon resonators is limited over large areas by polydispersity or a lack of long-range order. Here, we present an all-dielectric metamaterial fabricated with a low cost and highly scalable technique: a combination of soft imprinting nanolithography and chemical vapor deposition. The resulting all-dielectric metasurface is composed of an array of silicon hemispheres on top of a high refractive index dielectric substrate. This architecture allows the exploitation of high-quality Mie resonances at a large scale due to the high monodispersity of the hemispheres organized in a single crystal two-dimensional lattice. The optical response of the metasurface can be engineered by the design parameters of the nanoimprinted structure. We further demonstrate the potential of this platform to enhance light emission by coupling dye molecules to the sustained Mie resonances and measuring both an eight-fold amplified signal and a triple lifetime reduction.

scholarly journals 'Tiny numbers' are actually tiny: Evidence from gestures in the TV News Archive

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242142
Author(s):  
Greg Woodin ◽  
Bodo Winter ◽  
Marcus Perlman ◽  
Jeannette Littlemore ◽  
Teenie Matlock
Keyword(s):  
Large Scale ◽  
English Language ◽  
Real Life ◽  
Huge Number ◽  
Left Handed ◽  
News Broadcasts ◽  
Tv News ◽  
Numerical Magnitudes ◽  
Open Versus ◽  
Work Supports

We report a large-scale, quantitative investigation of manual gestures that speakers perform when speaking metaphorically about numerical quantities. We used the TV News Archive–an online database of over 2 million English language news broadcasts–to examine 681 videos in which 584 speakers used the phrase 'tiny number', 'small number', 'large number', or 'huge number', which metaphorically frame numerical quantity in terms of physical size. We found that the gestures speakers used reflect a number of different strategies to express the metaphoric size of quantities. When referring to greater versus lesser quantities, speakers were far more likely to gesture (1) with an open versus closed hand configuration, (2) with an outward versus inward movement, and (3) with a wider distance between the gesturing hands. These patterns were often more pronounced for the phrases containing more extreme adjectives ('tiny/huge number'). However, we did not find that speakers performed two-handed versus one-handed gestures. Nor did we find that speakers performed right-handed versus left-handed gestures, when referring to greater versus lesser quantities. Overall, this work supports the claim that metaphoric thought is involved in the production of verbal metaphors that describe numerical magnitudes. It demonstrates that size-based numerical associations observed in previous lab experiments are active in real-life communication outside the lab.

scholarly journals Prediction of polyproline II secondary structure propensity in proteins

2020 ◽  
Vol 7 (1) ◽  
pp. 191239 ◽  
Author(s):  
Kevin T. O’Brien ◽  
Catherine Mooney ◽  
Cyril Lopez ◽  
Gianluca Pollastri ◽  
Denis C. Shields
Keyword(s):  
Secondary Structure ◽  
Large Scale ◽  
External Validation ◽  
Three Dimensional ◽  
Binding Domains ◽  
Left Handed ◽  
Polyproline Ii ◽  
Polyproline Ii Helix ◽  
Binding Peptides ◽  
Validation Set

Background: The polyproline II helix (PPIIH) is an extended protein left-handed secondary structure that usually but not necessarily involves prolines. Short PPIIHs are frequently, but not exclusively, found in disordered protein regions, where they may interact with peptide-binding domains. However, no readily usable software is available to predict this state. Results: We developed PPIIPRED to predict polyproline II helix secondary structure from protein sequences, using bidirectional recurrent neural networks trained on known three-dimensional structures with dihedral angle filtering. The performance of the method was evaluated in an external validation set. In addition to proline, PPIIPRED favours amino acids whose side chains extend from the backbone (Leu, Met, Lys, Arg, Glu, Gln), as well as Ala and Val. Utility for individual residue predictions is restricted by the rarity of the PPIIH feature compared to structurally common features. Conclusion: The software, available at http://bioware.ucd.ie/PPIIPRED , is useful in large-scale studies, such as evolutionary analyses of PPIIH, or computationally reducing large datasets of candidate binding peptides for further experimental validation.

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