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Find video protocols related to scientific articles indexed in Pubmed.
Observation of valley-dependent beams in photonic graphene.
Opt Express
PUBLISHED: 10-17-2014
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Valley-dependent propagation of light in an artificial photonic hexagonal lattice, akin to electrons in graphene, is investigated in microwave regime. Both numerical and experimental results show that the valley degeneracy in the photonic graphene is broken when the frequency is away from the Dirac point. The peculiar anisotropic wave transport property due to distinct valleys is analyzed using the equifrequency contours. More interestingly, the valley-dependent self-collimation and beam splitting phenomena are experimentally demonstrated with the armchair and zigzag interfaces, respectively. Our results confirm that there are two inequivalent Dirac points that lead to two distinct valleys in photonic graphene, which could be used to control the flow of light and might be used to carry information in valley polarized beam splitter, collimator or guiding device.
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Broadband metasurfaces with simultaneous control of phase and amplitude.
Adv. Mater. Weinheim
PUBLISHED: 04-02-2014
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By combining the freedom of both the structural design and the orientation of split ring resonator antennas, we demonstrate terahertz metasurfaces that are capable of controlling both the phase and amplitude profiles over a very broad bandwidth. As an example, we show that the phase-amplitude metasurfaces can be engineered to control the diffraction orders arbitrarily.
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Biosynthesis of catechin components is differentially regulated in dark-treated tea (Camellia sinensis L.).
Plant Physiol. Biochem.
PUBLISHED: 02-22-2014
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Tea (Camellia sinensis L.) is a crop with both commercial and medicinal value with remarkably high polyphenol content in the form of catechins. To understand the molecular regulation of catechin biosynthesis in tea, we treated the tea plants with darkness. We used qRT-PCR to validate the expression of genes involved in catechin biosynthesis. It indicated that dark treatment displayed different effects on the genes participating in tea flavonoid (FL) pathway. The early genes of FL biosynthesis pathway, CHSI, F3H and DFR, remained at steady expression levels when treated by darkness. It is noteworthy that the expression level of LAR increased and the level of ANS decreased under dark conditions. The vanillin assay showed that the dark-treated plants contained lower levels of total catechins than those grown under normal conditions. The HPLC analysis further demonstrated the changes in biosynthesis of catechins under these conditions. In accordance with the gene expression pattern, the content of epicatechins (ECs) declined and that of catechins (Cs) was elevated in response to the darkness. Our study uncovered the molecular mechanisms and biochemical changes of shading in tea cultivation.
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An efficient synthesis of 2,5-dihydrofuran-fused bicyclic skeletons via the Pd(II)-catalyzed tandem-cyclization reaction of 1,omega-bisallenols.
Org. Lett.
PUBLISHED: 02-17-2009
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A palladium(II)-catalyzed tandem double-cyclization reaction of 1,omega-bisallenols was developed to form 2,5-dihydrofuran-fused bicyclic skeletons. With "unsymmetric" substrates, the reaction may also be realized with one hydroxyl group being protected as the acetate. Optically active bicyclic products were prepared by applying the Novozym-435 catalyzed kinetic resolution and the tandem double cyclization of these optically active allenol-allenyl acetates. The reaction may proceed via an oxypalladation, insertion, and elimination process.
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Electromagnetic tunneling in a sandwich structure containing single negative media.
Phys Rev E Stat Nonlin Soft Matter Phys
PUBLISHED: 02-02-2009
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In this paper, the electromagnetic (EM) tunneling phenomenon in a sandwich structure consisting of an mu-negative (MNG) medium, air, and an epsilon-negative (ENG) medium is investigated by means of the transfer-matrix method and microwave experiments. Both results demonstrate that by properly choosing parameters, EM waves can efficiently tunnel through a long distance over several hundreds times the length of the device. Unlike in the ENG-MNG slabs, the electric and the magnetic field of the tunneling mode is interestingly separated and localized at the interface of MNG-air and ENG-air, respectively. Therefore, this structure may be important for potential applications in wireless information and energy transmission, for its high efficiency, security, and health.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.