huangzandong

Liver-specific ATP-citrate lyase inhibition by bempedoic acid decreases LDL-C and attenuates atherosclerosis

Nature Communications, Published online: 28 November 2016; doi:10.1038/ncomms13457

Statins are lipid-lowering drugs that prevent cardiovascular disease but tolerability is limited by severe side effects in muscles. Here the authors elucidate a liver-specific activation mechanism for bempedoic acid, a novel cholesterol-lowering drug, and show how it effectively reduces LDL-C and atherosclerotic burden in mice, but does not cause myotoxicty.

11.4% Efficiency non-fullerene polymer solar cells with trialkylsilyl substituted 2D-conjugated polymer as donor

Nature Communications, Published online: 1 December 2016; doi:10.1038/ncomms13651

In organic photovoltaics, non-fullerene acceptors relax matching rules and allow for the development of new donor polymers. Here, Bin et al. design a donor polymer and obtain high photoconversion efficiencies despite the low energy offset for hole transfer between the acceptor and the donor.

Nature Nanotechnology 10, 389 (2015). doi:10.1038/nnano.2015.94

Authors: Jiangtan Yuan & Jun Lou

A single layer of MoS2 can be used to fabricate a memristor by exploiting structural defects in the crystal.

Nature Nanotechnology 10, 682 (2015). doi:10.1038/nnano.2015.131

Authors: S. Dai, Q. Ma, M. K. Liu, T. Andersen, Z. Fei, M. D. Goldflam, M. Wagner, K. Watanabe, T. Taniguchi, M. Thiemens, F. Keilmann, G. C. A. M. Janssen, S-E. Zhu, P. Jarillo-Herrero, M. M. Fogler & D. N. Basov

Hexagonal boron nitride (h-BN) is a natural hyperbolic material, in which the dielectric constants are the same in the basal plane (εt ≡ εx = εy) but have opposite signs (εtεz < 0) in the normal plane (εz). Owing to this property, finite-thickness slabs of h-BN act as multimode waveguides for the propagation of hyperbolic phonon polaritons—collective modes that originate from the coupling between photons and electric dipoles in phonons. However, control of these hyperbolic phonon polaritons modes has remained challenging, mostly because their electrodynamic properties are dictated by the crystal lattice of h-BN. Here we show, by direct nano-infrared imaging, that these hyperbolic polaritons can be effectively modulated in a van der Waals heterostructure composed of monolayer graphene on h-BN. Tunability originates from the hybridization of surface plasmon polaritons in graphene with hyperbolic phonon polaritons in h-BN, so that the eigenmodes of the graphene/h-BN heterostructure are hyperbolic plasmon–phonon polaritons. The hyperbolic plasmon–phonon polaritons in graphene/h-BN suffer little from ohmic losses, making their propagation length 1.5–2.0 times greater than that of hyperbolic phonon polaritons in h-BN. The hyperbolic plasmon–phonon polaritons possess the combined virtues of surface plasmon polaritons in graphene and hyperbolic phonon polaritons in h-BN. Therefore, graphene/h-BN can be classified as an electromagnetic metamaterial as the resulting properties of these devices are not present in its constituent elements alone.

Nature Nanotechnology 10, 569 (2015). doi:10.1038/nnano.2015.142

Authors: Masayuki Endo & Hiroshi Sugiyama

A nucleic acid-based chloride sensor is used to image and quantify spatiotemporal chloride transport in the living cell.

Negative refractive index and acoustic superlens from multiple scattering in single negative metamaterials

Nature 525, 7567 (2015). doi:10.1038/nature14678

Authors: Nadège Kaina, Fabrice Lemoult, Mathias Fink & Geoffroy Lerosey

Metamaterials, man-made composite media structured on a scale much smaller than a wavelength, offer surprising possibilities for engineering the propagation of waves. One of the most interesting of these is the ability to achieve superlensing—that is, to focus or image beyond the diffraction limit. This originates from the left-handed behaviour—the property of refracting waves negatively—that is typical of negative index metamaterials. Yet reaching this goal requires the design of ‘double negative’ metamaterials, which act simultaneously on the permittivity and permeability in electromagnetics, or on the density and compressibility in acoustics; this generally implies the use of two different kinds of building blocks or specific particles presenting multiple overlapping resonances. Such a requirement limits the applicability of double negative metamaterials, and has, for example, hampered any demonstration of subwavelength focusing using left-handed acoustic metamaterials. Here we show that these strict conditions can be largely relaxed by relying on media that consist of only one type of single resonant unit cell. Specifically, we show with a simple yet general semi-analytical model that judiciously breaking the symmetry of a single negative metamaterial is sufficient to turn it into a double negative one. We then demonstrate that this occurs solely because of multiple scattering of waves off the metamaterial resonant elements, a phenomenon often disregarded in these media owing to their subwavelength patterning. We apply our approach to acoustics and verify through numerical simulations that it allows the realization of negative index acoustic metamaterials based on Helmholtz resonators only. Finally, we demonstrate the operation of a negative index acoustic superlens, achieving subwavelength focusing and imaging with spot width and resolution 7 and 3.5 times better than the diffraction limit, respectively. Our findings have profound implications for the physics of metamaterials, highlighting the role of their subwavelength crystalline structure, and hence entering the realm of metamaterial crystals. This widens the scope of possibilities for designing composite media with novel properties in a much simpler way than has been possible so far.

Title: Band-gap calculations of anisotropic phononic crystals in a square lattice
Author(s): Li, Feng-Lian
Source: PROCEEDINGS OF THE 3RD INTERNATIONAL CONFERENCE ON MECHATRONICS, ROBOTICS AND AUTOMATION (ICMRA 2015), 15: 131-134 2015
Document Type: Proceedings Paper

Title: Flexural vibration band gaps in a double-side phononic crystal plate
Author(s): Zhao, Hao-Jiang; Guo, Hong-Wei; Li, Bing-Yan; et al.
Source: JOURNAL OF APPLIED PHYSICS, 118 (4): JUL 28 2015
Document Type: Article

Title: Hypersonic phononic stopbands at small angles of wave incidence in porous silicon multilayers
Author(s): Aliev, Gazi N.; Goller, Bernhard
Source: JOURNAL OF PHYSICS D-APPLIED PHYSICS, 48 (32): AUG 19 2015
Document Type: Article

Title: Review of magnetostrictive patch transducers and applications in ultrasonic nondestructive testing of waveguides
Author(s): Kim, Yoon Young; Kwon, Young Eui
Source: ULTRASONICS, 62: 3-19 SEP 2015
Document Type: Article

Title: Adhesion-induced instabilities and pattern formation in thin films of elastomers and gels
Author(s): Chaudhury, Manoj K.; Chakrabarti, Aditi; Ghatak, Animangsu
Source: EUROPEAN PHYSICAL JOURNAL E, 38 (7): JUL 31 2015
Document Type: Article

Review

There is currently intensive research underway into the development of non-layer structured two dimensional nanomaterials. Here, Zhang et al. review the research progress on the most promising wet-chemical synthesis methods as well as a wide range of applications of this unique class of materials.

Nature Communications doi: 10.1038/ncomms8873

Authors: Chaoliang Tan, Hua Zhang

Article

Super-resolution imaging is based on the restoration of evanescent and propagative waves. Here, the authors present an acoustic metamaterial that transmits only components of the acoustic field equal to or smaller than the operating wavelength, which can be used to provide sharp images of the edge of an object.

Nature Communications doi: 10.1038/ncomms9037

Authors: Miguel Molerón, Chiara Daraio