Nature Materials contents: April 2014 Volume 13 Number 4 pp317-426

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Advertisement Frontiers in Materials has launched! As a journal driven and directed by working scientists, for working scientists, Frontiers in Materials will be your portal to our open access publishing platform and research network, allowing you to connect and collaborate with researchers across the globe. Follow us on Facebook for more information or email us if you have any questions TABLE OF CONTENTS April 2014 Volume 13, Issue 4 Correction Editorial Commentary Interview Research Highlights News and Views Progress Article Letters Articles Subscribe   Facebook   RSS   Recommend to library   Twitter   Advertisement Download the new NatureJournals app and gain access to Nature and all Nature-branded research and review journals. All news content and open access articles are free. Subscribe to additional journals in the app for just $35.99*.  *Apple exchange rates apply. Limited time offer available on all journals except Scientific Reports. iPad, iPhone and iPod touch are trademarks of Apple Inc.   Correction Top Correction   p317 doi:10.1038/nmat3919 Editorial Top The Arabs' scientific vision   p317 doi:10.1038/nmat3940 Winds of change blow through research centres and universities operating in the Middle East. Commentary Top Dire need for a Middle Eastern science spring   pp318 - 320 Ahmed H. Zewail doi:10.1038/nmat3918 The Middle East is rich in human and natural resources, but many of its countries need a cultural and scientific transformation to reach worldwide recognition in education, research and economic productivity. Several institutions are making a positive impact, kindling hope for a successful 'science spring'. Interview Top Changing attitudes in Saudi Arabia   pp321 - 322 Luigi Martiradonna doi:10.1038/nmat3899 Jean M. J. Fréchet, vice-president for research at the King Abdullah University of Science and Technology (KAUST), talked to Nature Materials about the achievements of this institution since its foundation in 2009 and its contribution to shaping research attitudes in Saudi Arabia. Research Highlights Top Rapid current switching | Live diffraction | Intermolecular intrusions | Twisting thread | Acoustic diodes News and Views Top Liquid crystals: Electric fields line up graphene oxide   pp325 - 326 Ju Young Kim & Sang Ouk Kim doi:10.1038/nmat3929 The macroscopic alignment of dilute dispersions of graphene oxide can be controlled, with extremely large optical sensitivity, through the application of weak electric fields. See also: Article by Shen et al. Superconductivity: Squeezing out the current   pp326 - 327 Joseph V. Minervini doi:10.1038/nmat3931 In spite of their promise, practical applications of high-temperature cuprate superconductors have been hard to come by. The development of a method to fabricate round wires of the cuprate system Bi-2212 may begin to change this. See also: Article by Larbalestier et al. Material witness: Soft-hearted robots   p327 Philip Ball doi:10.1038/nmat3930 Graphene synthesis: Graphene closer to fruition   pp328 - 329 Jaime A. Torres & Richard B. Kaner doi:10.1038/nmat3925 Cracks and defects induced during the transfer of large-area graphene on insulating substrates impair its excellent electronic properties. A defect-free transfer can now be obtained thanks to capillary bridges that anchor the graphene film to the substrate while the underlying growth layer is etched away. Bioinspired materials: Boosting plant biology   pp329 - 331 Gregory D. Scholes & Edward H. Sargent doi:10.1038/nmat3926 Chloroplasts with extended photosynthetic activity beyond the visible absorption spectrum, and living leaves that perform non-biological functions, are made possible by localizing nanoparticles within plant organelles. See also: Article by Giraldo et al. Cell migration: Electrifying movement   pp331 - 332 Nir Gov doi:10.1038/nmat3928 Electric fields prompt epithelial cell populations to make coordinated movements such as U-turns. See also: Article by Cohen et al. Nature Materials JOBS of the week PhD research fellow: Computational Materials Science University of Oslo 2 PhD Soft Matter Fluid Mechanics Biophysics Aix-Marseille Université Scientist in Computational Fluid Dyanamics and HPC Science and Technology Facilities Council (STFC) Professor in Proton Conductors Technical University of Denmark (DTU) PhD Position: Quantum Optics in Integrated Structures University of Southampton More Science jobs from Nature Materials EVENT International Conference on Oxide Materials for Electronic Engineering 26.05.14 Lviv, Ukraine More science events from Progress Article Top Microimaging of transient guest profiles to monitor mass transfer in nanoporous materials   pp333 - 343 Jörg Kärger, Tomas Binder, Christian Chmelik, Florian Hibbe, Harald Krautscheid, Rajamani Krishna & Jens Weitkamp doi:10.1038/nmat3917 Microimaging techniques, such as interference and infrared microscopy, can be used as a tool to directly monitor guest profiles within nanoporous materials. Observation of the variation in these profiles leads to unprecedented insight into transport phenomena, including intracrystalline diffusion and surface permeation. Letters Top Electric-field control of magnetic order above room temperature   pp345 - 351 R. O. Cherifi, V. Ivanovskaya, L. C. Phillips, A. Zobelli, I. C. Infante, E. Jacquet, V. Garcia, S. Fusil, P. R. Briddon, N. Guiblin, A. Mougin, A. A. Ünal, F. Kronast, S. Valencia, B. Dkhil, A. Barthélémy & M. Bibes doi:10.1038/nmat3870 Electric-field-induced switching of material’s magnetization is a promising approach for achieving energy-efficient memory devices. By taking advantage of the strong magnetoelectric coupling with a BaTiO3 substrate, a small electric field is used to switch a FeRh thin film from anti- to ferromagnetic above room temperature. Three-dimensional broadband omnidirectional acoustic ground cloak   pp352 - 355 Lucian Zigoneanu, Bogdan-Ioan Popa & Steven A. Cummer doi:10.1038/nmat3901 In addition to controlling the propagation of light, metamaterials have also received attention for controlling sound. Now, a device that can act as a broadband and omnidirectional acoustic cloak is experimentally demonstrated. Articles Top Quantum criticality in a metallic spin liquid   pp356 - 359 Y. Tokiwa, J. J. Ishikawa, S. Nakatsuji & P. Gegenwart doi:10.1038/nmat3900 Quantum spin liquids are a state of magnetic order that, in analogy with ordinary liquids, is characterized by fluctuating, disordered spins. By means of specific heat measurements, the frustrated Kondo system Pr2Ir2O7 is shown to undergo a transition to such a state in zero magnetic field. Voltage tuning of thermal spin current in ferromagnetic tunnel contacts to semiconductors   pp360 - 366 Kun-Rok Jeon, Byoung-Chul Min, Aurelie Spiesser, Hidekazu Saito, Sung-Chul Shin, Shinji Yuasa & Ron Jansen Sung-Chul Shin doi:10.1038/nmat3869 Spin currents form the basis of spintronics as a viable approach for future memory and information storage devices. Now, it is shown that a thermal spin current can be induced and controlled by applying a voltage. Room-temperature antiferromagnetic memory resistor   pp367 - 374 X. Marti, I. Fina, C. Frontera, Jian Liu, P. Wadley, Q. He, R. J. Paull, J. D. Clarkson, J. Kudrnovský, I. Turek, J. Kuneš, D. Yi, J-H. Chu, C. T. Nelson, L. You, E. Arenholz, S. Salahuddin, J. Fontcuberta, T. Jungwirth & R. Ramesh doi:10.1038/nmat3861 Magnetic memory devices are typically based on ferromagnetic materials. Now, a memory resistor based on the antiferromagnetic alloy FeRh is demonstrated at room temperature. Isotropic round-wire multifilament cuprate superconductor for generation of magnetic fields above 30 T   pp375 - 381 D. C. Larbalestier, J. Jiang, U. P. Trociewitz, F. Kametani, C. Scheuerlein, M. Dalban-Canassy, M. Matras, P. Chen, N. C. Craig, P. J. Lee & E. E. Hellstrom doi:10.1038/nmat3887 Cuprate superconductors have found limited application for high-field magnets because of difficulties related to grain boundaries. Now, this issue is partially overcome and round wires suitable for magnetic coils are fabricated from Bi2Sr2CaCu2O8−x. See also: News and Views by Minervini Organo-erbium systems for optical amplification at telecommunications wavelengths   pp382 - 386 H. Q. Ye, Z. Li, Y. Peng, C. C. Wang, T. Y. Li, Y. X. Zheng, A. Sapelkin, G. Adamopoulos, I. Hernández, P. B. Wyatt & W. P. Gillin doi:10.1038/nmat3910 Optical amplifiers based on erbium ions typically require high pump power densities to produce gain. Now, an organic optical amplifier material composed of erbium ions and a zinc-based organic chromophore is demonstrated to reach population inversion using low-power visible light. Accelerating charging dynamics in subnanometre pores   pp387 - 393 Svyatoslav Kondrat, Peng Wu, Rui Qiao & Alexei A. Kornyshev doi:10.1038/nmat3916 The energy density of supercapacitors can be enhanced by using ionic liquids and electrodes with subnanometre pores, but this tends to reduce their power density. The mechanisms of charging subnanometre pores with ionic liquids are now clarified and molecular simulations suggest that charging of such ionophilic pores is a diffusive process. Electro-optical switching of graphene oxide liquid crystals with an extremely large Kerr coefficient   pp394 - 399 Tian-Zi Shen, Seung-Ho Hong & Jang-Kun Song doi:10.1038/nmat3888 Although dispersions of aligned graphene oxide flakes are particularly attractive for electro-optic devices, controlling the alignment of the flakes by using electric fields has proved difficult. It is now shown that the macroscopic alignment of graphene oxide liquid crystals can be controlled through the application of weak electric fields when interflake interactions are sufficiently small, giving rise to the largest Kerr coefficient in a molecular liquid crystal. See also: News and Views by Kim & Kim Plant nanobionics approach to augment photosynthesis and biochemical sensing   pp400 - 408 Juan Pablo Giraldo, Markita P. Landry, Sean M. Faltermeier, Thomas P. McNicholas, Nicole M. Iverson, Ardemis A. Boghossian, Nigel F. Reuel, Andrew J. Hilmer, Fatih Sen, Jacqueline A. Brew & Michael S. Strano doi:10.1038/nmat3890 Imparting non-native functions to living plants using nanoparticles opens the possibility of creating synthetic materials that can grow and repair themselves using sunlight, water and carbon dioxide. It is now shown that, both in plant extracts and living leaves, carbon nanotubes traverse and localize within the lipid envelope of plant chloroplasts, enhance their photosynthetic activity, and enable near-infrared fluorescence monitoring of nitric oxide. See also: News and Views by Scholes & Sargent Galvanotactic control of collective cell migration in epithelial monolayers   pp409 - 417 Daniel J. Cohen, W. James Nelson & Michel M. Maharbiz doi:10.1038/nmat3891 The collective migration of epithelial cells arises from the interplay between intercellular forces and cellular signalling networks. It is now shown that the migration of an epithelium can be controlled by applying electric fields that bias the signalling networks, and that such galvanotactic control can prompt cell populations to make coordinated U-turns, undergo divergent or convergent migration, or move against an obstacle. See also: News and Views by Gov The in vivo activation of persistent nanophosphors for optical imaging of vascularization, tumours and grafted cells   pp418 - 426 Thomas Maldiney, Aurélie Bessière, Johanne Seguin, Eliott Teston, Suchinder K. Sharma, Bruno Viana, Adrie J. J. Bos, Pieter Dorenbos, Michel Bessodes, Didier Gourier, Daniel Scherman & Cyrille Richard doi:10.1038/nmat3908 The use of persistent luminescence nanoparticles for in vivo optical imaging commonly requires ex vivo activation before systemic administration, hampering longer-term imaging capabilities. Now, it is shown that near-infrared emitting nanoprobes based on chromium-doped zinc gallate can be activated in vivo using low-energy red light and used for tumour-targeted imaging and cell tracking experiments. Top Advertisement They're recruiting scientists just like you! The Naturejobs Career Expo is coming to Boston, Massachusetts on May 20, 2014. Take advantage of this free opportunity to meet employers, attend workshops and further develop your career. Don't wait-register today!      Natureevents is a fully searchable, multi-disciplinary database designed to maximise exposure for events organisers. The contents of the Natureevents Directory are now live. The digital version is available here. Find the latest scientific conferences, courses, meetings and symposia on natureevents.com. For event advertising opportunities across the Nature Publishing Group portfolio please contact natureevents@nature.com More Nature Events

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