Nature Materials contents: October 2013 Volume 12 Number 10 pp 865-944

Advertisement See what you've been missing with NEW Agilent Cary 7000 UMS   Agilent introduces a revolution in solid sample measurement - the Cary 7000 Universal Measurement Spectrophotometer (UMS). Watch video, view webinar, receive a FREE Information Kit and learn how the NEW Cary 7000 will advance your materials analysis. TABLE OF CONTENTS October 2013 Volume 12, Issue 10 Editorial Commentary Research Highlights News and Views Letters Articles Advertisement   Protein engineering and other bio-synthetic routes for bio-based materials: Current uses and potential applications Topic Editors: Carissa M. Soto and Cherise Bernard ¦ Submission deadline: 17 Feb 2014   In this Research Topic from Frontiers in Chemistry, the topic editors aim to cover current uses and envision future applications of materials generated using protein engineering and biosynthesis techniques. Find out more on how you can contribute to this Research Topic or even host your own Subscribe   Facebook   RSS   Recommend to library   Twitter   Advertisement Nature Video in association with Scientific American present: Better living through chemistry Four debates from the 2013 Nobel Laureate Meeting in Lindau. We invited Nobel laureates and young researchers to discuss how chemistry can solve pressing world problems.  Access the videos.        Editorial Top Not so transparent   p865 doi:10.1038/nmat3773 As with the ongoing debate on the degree of wetting transparency of supported graphene, transparency in both pre- and post-publication peer review is a contentious concept. Commentary Top Wetting translucency of graphene   pp866 - 869 Chih-Jen Shih, Michael S. Strano and Daniel Blankschtein doi:10.1038/nmat3760 For the case of water on supported graphene, about 30% of the van der Waals interactions between the water and the substrate are transmitted through the one-atom-thick layer. See also: Article by Li et al. | News and Views by Xu & Heath Research Highlights Top The logic of graphene | Hyperelastic nanowires | Changing domains | Artificially cool | Plasmonic darkness News and Views Top Flexible electronics: Sophisticated skin   pp871 - 872 Siegfried Bauer doi:10.1038/nmat3759 Advances in materials science and layout design have enabled the realization of flexible and multifunctional electronic devices. Two demonstrations of electronic skins, which combine temperature and pressure sensing with integrated thermal actuators and organic displays, unveil the potential of these devices for robotics and clinical applications. See also: Article by Webb et al. | Letter by Wang et al. Wetting: Contact with what?   pp872 - 873 Ke Xu and James R. Heath doi:10.1038/nmat3763 Pristine graphitic surfaces seem to be more hydrophilic than previously assumed because of the unexpected influence of the quick adsorption of hydrocarbons from air. See also: Article by Li et al. | Commentary by Shih et al. Bilayer graphene: A little twist with big consequences   pp874 - 875 Philip Hofmann doi:10.1038/nmat3764 A study on the subtle interplay between electronic structure and structural defects now explains why the suppression of conduction in the insulating state of bilayer graphene is not as strong as might be expected. It also reveals the possibility of creating graphene-based nanoscale systems with unique electronic properties. See also: Letter by Kim et al. Interface superconductivity: Pinning the critical temperature   pp875 - 876 Dirk van der Marel doi:10.1038/nmat3761 The critical temperature of most superconductors varies with the density of charge carriers, which in turn is most easily tuned by chemical doping. The observation that a specially fabricated two-dimensional superconductor maintains the same critical temperature regardless of doping raises some important questions. See also: Letter by Wu et al. Material witness: And the winner is...   p876 Philip Ball doi:10.1038/nmat3762 Nature Materials JOBS of the week PhD in Materials / Inorganic Chemistry Curtin University Research fellow or post doctoral position in computational physics for magnetic materials Pukyong National University Assistant Professor in Inorganic Materials UC Santa Barbara More Science jobs from Nature Materials EVENT Molecules and Materials for Artificial Photosynthesis 09.02.14 Cancun, Mexico More science events from Letters Top Anomalous independence of interface superconductivity from carrier density   pp877 - 881 J. Wu, O. Pelleg, G. Logvenov, A. T. Bollinger, Y-J. Sun, G. S. Boebinger, M. Vanević, Z. Radović & I. Božović doi:10.1038/nmat3719 The emergence of superconductivity of insulating oxide interfaces has raised a number of intriguing theoretical challenges. Now, the critical temperature of strontium-doped lanthanum cuprate bilayer samples is shown to remain unchanged over a wide doping range, implying that changes in the carrier density cannot be the origin of the enhanced critical temperatures seen with respect to single-phase samples. See also: News and Views by van der Marel Speed limit of the insulator–metal transition in magnetite   pp882 - 886 S. de Jong, R. Kukreja, C. Trabant, N. Pontius, C. F. Chang, T. Kachel, M. Beye, F. Sorgenfrei, C. H. Back, B. Bräuer, W. F. Schlotter, J. J. Turner, O. Krupin, M. Doehler, D. Zhu, M. A. Hossain, A. O. Scherz, D. Fausti, F. Novelli, M. Esposito, W. S. Lee, Y. D. Chuang, D. H. Lu, R. G. Moore, M. Yi, M. Trigo, P. Kirchmann, L. Pathey, M. S. Golden, M. Buchholz, P. Metcalf, F. Parmigiani, W. Wurth, A. Fählisch, C. Schüßler-Langeheine & H. A. Dürr doi:10.1038/nmat3718 The insulator-to-metal transition occurring in magnetite is known as the Verwey transition, and its precise mechanism has recently come under renewed attention. Using pump–probe X-ray diffraction and optical reflectivity techniques, the dynamics of excitations known as trimerons are now examined, revealing the switching limits of this ubiquitous oxide material. Coexisting massive and massless Dirac fermions in symmetry-broken bilayer graphene   pp887 - 892 Keun Su Kim, Andrew L. Walter, Luca Moreschini, Thomas Seyller, Karsten Horn, Eli Rotenberg & Aaron Bostwick doi:10.1038/nmat3717 As indicated by direct band-structure measurements and calculations, tiny native imperfections in bilayer graphene are sufficient to cause the generation of coexisting massive and massless Dirac fermions. The massless spectrum is robust against strong electric fields and has a closed-arc topology consisting of a unique chiral pseudospin texture See also: News and Views by Hofmann Fabrication and deformation of three-dimensional hollow ceramic nanostructures   pp893 - 898 Dongchan Jang, Lucas R. Meza, Frank Greer and Julia R. Greer doi:10.1038/nmat3738 Hard biological materials such as diatoms and sea sponges can inspire the design of structural materials that are mechanically robust yet lightweight. Hollow titanium nitride lattices have now been fabricated that mimic the length scales (from 10 nm to 100 µm) and hierarchy of biological materials. These lattices attain tensile strengths of 1.75 GPa without failing (even after multiple deformation cycles) because of the low probability of pre-existing flaws. User-interactive electronic skin for instantaneous pressure visualization   pp899 - 904 Chuan Wang, David Hwang, Zhibin Yu, Kuniharu Takei, Junwoo Park, Teresa Chen, Biwu Ma & Ali Javey doi:10.1038/nmat3711 Flexible devices mimicking the sensitivity of human skin typically turn pressure stimuli into electronic signals, which must be further processed to be interpreted by the user. By integrating an active matrix of organic light-emitting diodes in these foldable sensors, pressure can now control the brightness of each coloured pixel, enabling the direct visualization and quantification of the applied stimulus. See also: News and Views by Bauer Articles Top Uncovering the intrinsic size dependence of hydriding phase transformations in nanocrystals   pp905 - 912 Rizia Bardhan, Lester O. Hedges, Cary L. Pint, Ali Javey, Stephen Whitelam & Jeffrey J. Urban doi:10.1038/nmat3716 Although quantitative understanding of nanocrystal phase transformations is important for efficient energy conversion and catalysis, difficulties in directly monitoring nanoscale systems in reactive environments remain. Direct quantification of hydriding transformations in palladium nanocrystals now clearly reveals that the transformation rates are governed by nanocrystal dimensions. Thermoelectric imaging of structural disorder in epitaxial graphene   pp913 - 918 Sanghee Cho, Stephen Dongmin Kang, Wondong Kim, Eui-Sup Lee, Sung-Jae Woo, Ki-Jeong Kong, Ilyou Kim, Hyeong-Do Kim, Tong Zhang, Joseph A. Stroscio, Yong-Hyun Kim & Ho-Ki Lyeo doi:10.1038/nmat3708 Heat is a form of energy that is transported from a hot to a cold region, but it is not a notion that is associated with the microscopic measurement of electronic properties. It is now shown that local thermoelectric measurements can be used for imaging structural disorder in graphene, with high sensitivity, on the atomic and nanometre scales, uncovering soliton-like domain-wall line-patterns separating different graphene regions. The effect of particle proximity on the oxygen reduction rate of size-selected platinum clusters   pp919 - 924 Markus Nesselberger, Melanie Roefzaad, R. Fayçal Hamou, P. Ulrich Biedermann, Florian F. Schweinberger, Sebastian Kunz, Katrin Schloegl, Gustav K. H. Wiberg, Sean Ashton, Ueli Heiz, Karl J. J. Mayrhofer & Matthias Arenz doi:10.1038/nmat3712 The catalytic activity of highly dispersed platinum nanoparticles is not yet well understood. Now, a unique approach that allows precise control of both the size and coverage of platinum nanoclusters reveals that particle proximity influences the oxygen reduction rate of these size-selected clusters, especially in terms of mass normalized activity. Effect of airborne contaminants on the wettability of supported graphene and graphite   pp925 - 931 Zhiting Li, Yongjin Wang, Andrew Kozbial, Ganesh Shenoy, Feng Zhou, Rebecca McGinley, Patrick Ireland, Brittni Morganstein, Alyssa Kunkel, Sumedh P. Surwade, Lei Li & Haitao Liu doi:10.1038/nmat3709 Contact-angle and spectroscopy experiments on clean supported graphene and graphite show that these surfaces become more hydrophobic as they adsorb airborne hydrocarbons. Furthermore, the water contact angle on these graphitic surfaces decreases if these contaminants are partially removed by both thermal annealing and controlled ultraviolet–ozone treatments, suggesting that graphitic surfaces are more hydrophilic than previously believed. See also: News and Views by Xu & Heath | Commentary by Shih et al. Physical hydrogels composed of polyampholytes demonstrate high toughness and viscoelasticity   pp932 - 937 Tao Lin Sun, Takayuki Kurokawa, Shinya Kuroda, Abu Bin Ihsan, Taigo Akasaki, Koshiro Sato, Md. Anamul Haque, Tasuku Nakajima & Jian Ping Gong doi:10.1038/nmat3713 Polyampholyte hydrogels synthesized from the random polymerization of oppositely charged ionic monomers are shown to be mechanically tough and highly viscoelastic. Strong ionic bonds within the gel act as permanent crosslinks and weaker ionic bonds reversibly break and re-form, enhancing the fracture resistance, shock absorbance and self-healing properties of the materials. Ultrathin conformal devices for precise and continuous thermal characterization of human skin   pp938 - 944 R. Chad Webb, Andrew P. Bonifas, Alex Behnaz, Yihui Zhang, Ki Jun Yu, Huanyu Cheng, Mingxing Shi, Zuguang Bian, Zhuangjian Liu, Yun-Soung Kim, Woon-Hong Yeo, Jae Suk Park, Jizhou Song, Yuhang Li, Yonggang Huang, Alexander M. Gorbach & John A. Rogers doi:10.1038/nmat3755 A strategy for assessing blood microcirculation and tissue hydration relies on monitoring the temperature and thermal conductivity of skin, respectively. It is now shown that arrays of micrometre-sized sensors and heaters can be integrated on stretchable substrates that conformably adhere to the skin; these devices allow spatially resolved heating and real-time temperature mapping in patients without limiting their motion. See also: News and Views by Bauer Top Advertisement Nature Publishing Index 2012 Global The Nature Publishing Index (NPI) ranks institutions and countries according to the number of primary research articles they publish in the Nature family of journals in a one-year period. 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