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Science Advances

Zi-Xiang Li, Abolhassan Vaezi, Christian B Mendl, Hong Yao
No definitive evidence of spacetime supersymmetry (SUSY) that transmutes fermions into bosons and vice versa has been revealed in nature so far. Moreover, the question of whether spacetime SUSY in 2 + 1 and higher dimensions can emerge in generic lattice microscopic models remains open. Here, we introduce a lattice realization of a single Dirac fermion in 2 + 1 dimensions with attractive interactions that preserves both time-reversal and chiral symmetries. By performing sign problem-free determinant quantum Monte Carlo simulations, we show that an interacting single Dirac fermion in 2 + 1 dimensions features a superconducting quantum critical point (QCP)...
November 2018: Science Advances
Kewang Nan, Stephen Dongmin Kang, Kan Li, Ki Jun Yu, Feng Zhu, Juntong Wang, Alison C Dunn, Chaoqun Zhou, Zhaoqian Xie, Matthias T Agne, Heling Wang, Haiwen Luan, Yihui Zhang, Yonggang Huang, G Jeffrey Snyder, John A Rogers
With accelerating trends in miniaturization of semiconductor devices, techniques for energy harvesting become increasingly important, especially in wearable technologies and sensors for the internet of things. Although thermoelectric systems have many attractive attributes in this context, maintaining large temperature differences across the device terminals and achieving low-thermal impedance interfaces to the surrounding environment become increasingly difficult to achieve as the characteristic dimensions decrease...
November 2018: Science Advances
P-Q Elias, N Severac, J-M Luyssen, Y-B André, I Doudet, B Wattellier, J-P Tobeli, S Albert, B Mahieu, R Bur, A Mysyrowicz, A Houard
When a flying object becomes supersonic, a concomitant increase in drag leads to a considerable rise in fuel consumption. We show experimentally that an embarked terawatt femtosecond laser can significantly decrease this drag. We measured a 50% transient reduction of drag on a test model placed in a supersonic wind tunnel at Mach 3. This effect was initiated by the thin hot air column created in front of the supersonic object by filamentation of the laser pulse. We also show that this technique offers possibilities for steering...
November 2018: Science Advances
Huichao Wang, Haiwen Liu, Yanan Li, Yongjie Liu, Junfeng Wang, Jun Liu, Ji-Yan Dai, Yong Wang, Liang Li, Jiaqiang Yan, David Mandrus, X C Xie, Jian Wang
Quantum oscillations are usually the manifestation of the underlying physical nature in condensed matter systems. Here, we report a new type of log-periodic quantum oscillations in ultraquantum three-dimensional topological materials. Beyond the quantum limit (QL), we observe the log-periodic oscillations involving up to five oscillating cycles (five peaks and five dips) on the magnetoresistance of high-quality single-crystal ZrTe5 , virtually showing the clearest feature of discrete scale invariance (DSI)...
November 2018: Science Advances
Junjing Deng, Yuan Hung Lo, Marcus Gallagher-Jones, Si Chen, Alan Pryor, Qiaoling Jin, Young Pyo Hong, Youssef S G Nashed, Stefan Vogt, Jianwei Miao, Chris Jacobsen
Accurate knowledge of elemental distributions within biological organisms is critical for understanding their cellular roles. The ability to couple this knowledge with overall cellular architecture in three dimensions (3D) deepens our understanding of cellular chemistry. Using a whole, frozen-hydrated Chlamydomonas reinhardtii cell as an example, we report the development of 3D correlative microscopy through a combination of simultaneous cryogenic x-ray ptychography and x-ray fluorescence microscopy. By taking advantage of a recently developed tomographic reconstruction algorithm, termed GENeralized Fourier Iterative REconstruction (GENFIRE), we produce high-quality 3D maps of the unlabeled alga's cellular ultrastructure and elemental distributions within the cell...
November 2018: Science Advances
Enduo Feng, Tingting Zheng, Xiaoxiao He, Jinquan Chen, Yang Tian
Surface-enhanced Raman scattering (SERS) probes based on a charge transfer (CT) process with high stability and reproducibility are powerful tools under open-air conditions. However, the key problem ahead of practical usage of CT-based SERS technology is how to effectively improve sensitivity. Here, a novel ternary heterostructure SERS substrate, Fe3 O4 @GO@TiO2 , with a significant enhancement factor of 8.08 × 106 was first synthesized. We found the remarkable enhanced effect of SERS signal to be attributed to the resonance effect of CuPc, CT between GO and TiO2 , and enrichment from a porous TiO2 shell...
November 2018: Science Advances
H Park, K H Lee, Y B Kim, S B Ambade, S H Noh, W Eom, J Y Hwang, W J Lee, J Huang, T H Han
Colloidal dispersions with liquid crystallinity hold great promise for fabricating their superstructures. As an example, when graphene oxide (GO) sheets are assembled in the liquid crystalline state, they can turn into ordered macroscopic forms of GO such as fibers via the wet spinning process. Here, we report that by reinforcing intersheet interactions, GO liquid crystals (LCs) turn into mechanically robust hydrogels that can be readily drawn into highly aligned fibrillar structures. GO hydrogel fibers with highly aligned sheets (orientation factor, f = 0...
November 2018: Science Advances
Zhiguang Wu, Jonas Troll, Hyeon-Ho Jeong, Qiang Wei, Marius Stang, Focke Ziemssen, Zegao Wang, Mingdong Dong, Sven Schnichels, Tian Qiu, Peer Fischer
The intravitreal delivery of therapeutic agents promises major benefits in the field of ocular medicine. Traditional delivery methods rely on the random, passive diffusion of molecules, which do not allow for the rapid delivery of a concentrated cargo to a defined region at the posterior pole of the eye. The use of particles promises targeted delivery but faces the challenge that most tissues including the vitreous have a tight macromolecular matrix that acts as a barrier and prevents its penetration. Here, we demonstrate novel intravitreal delivery microvehicles-slippery micropropellers-that can be actively propelled through the vitreous humor to reach the retina...
November 2018: Science Advances
Sheng Zhou, Yanying Wei, Libo Li, Yifan Duan, Qianqian Hou, Lili Zhang, Liang-Xin Ding, Jian Xue, Haihui Wang, Jürgen Caro
Metal-organic framework (MOF) membranes show great promise for propene/propane separation, yet a sharp molecular sieving has not been achieved due to their inherent linker mobility. Here, zeolitic imidazolate framework ZIF-8-type membranes with suppressed linker mobility are prepared by a fast current-driven synthesis (FCDS) strategy within 20 min, showing sharpened molecular sieving for propene/propane separation with a separation factor above 300. During membrane synthesis, the direct current promotes the metal ions and ligands to assemble into inborn-distorted and stiffer frameworks with ZIF-8_Cm (a newly discovered polymorph of ZIF-8) accounting for 60 to 70% of the membrane composition...
October 2018: Science Advances
Josua Jordi, Drago Guggiana-Nilo, Andrew D Bolton, Srishti Prabha, Kaitlyn Ballotti, Kristian Herrera, Andrew J Rennekamp, Randall T Peterson, Thomas A Lutz, Florian Engert
How appetite is modulated by physiological, contextual, or pharmacological influence is still unclear. Specifically, the discovery of appetite modulators is compromised by the abundance of side effects that usually limit in vivo drug action. We set out to identify neuroactive drugs that trigger only their intended single behavioral change, which would provide great therapeutic advantages. To identify these ideal bioactive small molecules, we quantified the impact of more than 10,000 compounds on an extended series of different larval zebrafish behaviors using an in vivo imaging strategy...
October 2018: Science Advances
Tanya M Smith, Christine Austin, Daniel R Green, Renaud Joannes-Boyau, Shara Bailey, Dani Dumitriu, Stewart Fallon, Rainer Grün, Hannah F James, Marie-Hélène Moncel, Ian S Williams, Rachel Wood, Manish Arora
Scholars endeavor to understand the relationship between human evolution and climate change. This is particularly germane for Neanderthals, who survived extreme Eurasian environmental variation and glaciations, mysteriously going extinct during a cool interglacial stage. Here, we integrate weekly records of climate, tooth growth, and metal exposure in two Neanderthals and one modern human from southeastern France. The Neanderthals inhabited cooler and more seasonal periods than the modern human, evincing childhood developmental stress during wintertime...
October 2018: Science Advances
James M Stafford, Chul-Hwan Lee, Philipp Voigt, Nicolas Descostes, Ricardo Saldaña-Meyer, Jia-Ray Yu, Gary Leroy, Ozgur Oksuz, Jessica R Chapman, Fernando Suarez, Aram S Modrek, N Sumru Bayin, Dimitris G Placantonakis, Matthias A Karajannis, Matija Snuderl, Beatrix Ueberheide, Danny Reinberg
A methionine substitution at lysine-27 on histone H3 variants (H3K27M) characterizes ~80% of diffuse intrinsic pontine gliomas (DIPG) and inhibits polycomb repressive complex 2 (PRC2) in a dominant-negative fashion. Yet, the mechanisms for this inhibition and abnormal epigenomic landscape have not been resolved. Using quantitative proteomics, we discovered that robust PRC2 inhibition requires levels of H3K27M greatly exceeding those of PRC2, seen in DIPG. While PRC2 inhibition requires interaction with H3K27M, we found that this interaction on chromatin is transient, with PRC2 largely being released from H3K27M...
October 2018: Science Advances
Hemant Suryawanshi, Pavel Morozov, Alexander Straus, Nicole Sahasrabudhe, Klaas E A Max, Aitor Garzia, Manjunath Kustagi, Thomas Tuschl, Zev Williams
The placenta and decidua interact dynamically to enable embryonic and fetal development. Here, we report single-cell RNA sequencing of 14,341 and 6754 cells from first-trimester human placental villous and decidual tissues, respectively. Bioinformatic analysis identified major cell types, many known and some subtypes previously unknown in placental villi and decidual context. Further detailed analysis revealed proliferating subpopulations, enrichment of cell type-specific transcription factors, and putative intercellular communication in the fetomaternal microenvironment...
October 2018: Science Advances
Jinjuan Xue, Huihui Liu, Suming Chen, Caiqiao Xiong, Lingpeng Zhan, Jie Sun, Zongxiu Nie
It is crucial but of a great challenge to study in vivo and in situ drug release of nanocarriers when developing a nanomaterial-based drug delivery platform. We developed a new label-free laser desorption/ionization mass spectrometry (MS) imaging strategy that enabled visualization and quantification of the in situ drug release in tissues by monitoring intrinsic MS signal intensity ratio of loaded drug over the nanocarriers. The proof of concept was demonstrated by investigating the doxorubicin (DOX)/polyethylene glycol-MoS2 nanosheets drug delivery system in tumor mouse models...
October 2018: Science Advances
N Voss, T H Dixon, Z Liu, R Malservisi, M Protti, S Schwartz
Slow slip events have been suggested to trigger subduction earthquakes. However, examples to date have been poorly recorded, occurring offshore, where data are sparse. Better understanding of slow slip events and their influence on subsequent earthquakes is critical for hazard forecasts. We analyze a well-recorded event beginning 6 months before the 2012 M w (moment magnitude) 7.6 earthquake in Costa Rica. The event migrates to the eventual megathrust rupture. Peak slip rate reached a maximum of 5 mm/day, 43 days before the earthquake, remaining high until the earthquake...
October 2018: Science Advances
Y Cao, H Chen, R Qiu, M Hanna, E Ma, M Hjort, A Zhang, R S Lewis, J C Wu, N A Melosh
Intracellular delivery of mRNA, DNA, and other large macromolecules into cells plays an essential role in an array of biological research and clinical therapies. However, current methods yield a wide variation in the amount of material delivered, as well as limitations on the cell types and cargoes possible. Here, we demonstrate quantitatively controlled delivery into a range of primary cells and cell lines with a tight dosage distribution using a nanostraw-electroporation system (NES). In NES, cells are cultured onto track-etched membranes with protruding nanostraws that connect to the fluidic environment beneath the membrane...
October 2018: Science Advances
A Steele, L G Benning, R Wirth, S Siljeström, M D Fries, E Hauri, P G Conrad, K Rogers, J Eigenbrode, A Schreiber, A Needham, J H Wang, F M McCubbin, D Kilcoyne, Juan Diego Rodriguez Blanco
The sources and nature of organic carbon on Mars have been a subject of intense research. Steele et al. (2012) showed that 10 martian meteorites contain macromolecular carbon phases contained within pyroxene- and olivine-hosted melt inclusions. Here, we show that martian meteorites Tissint, Nakhla, and NWA 1950 have an inventory of organic carbon species associated with fluid-mineral reactions that are remarkably consistent with those detected by the Mars Science Laboratory (MSL) mission. We advance the hypothesis that interactions among spinel-group minerals, sulfides, and a brine enable the electrochemical reduction of aqueous CO2 to organic molecules...
October 2018: Science Advances
Michael E Mann, Stefan Rahmstorf, Kai Kornhuber, Byron A Steinman, Sonya K Miller, Stefan Petri, Dim Coumou
Persistent episodes of extreme weather in the Northern Hemisphere summer have been associated with high-amplitude quasi-stationary atmospheric Rossby waves, with zonal wave numbers 6 to 8 resulting from the phenomenon of quasi-resonant amplification (QRA). A fingerprint for the occurrence of QRA can be defined in terms of the zonally averaged surface temperature field. Examining state-of-the-art [Coupled Model Intercomparison Project Phase 5 (CMIP5)] climate model projections, we find that QRA events are likely to increase by ~50% this century under business-as-usual carbon emissions, but there is considerable variation among climate models...
October 2018: Science Advances
Nasrollah Moradi, Bo Liu, Morten Iversen, Marcel M Kuypers, Helle Ploug, Arzhang Khalili
N2 -fixing colonies of cyanobacteria and aggregates of phytoplankton and detritus sinking hundreds of meters per day are instrumental for the ocean's sequestration of CO2 from the atmosphere. Understanding of small-scale microbial processes associated with phytoplankton colonies and aggregates is therefore crucial for understanding large-scale biogeochemical processes in the ocean. Phytoplankton colonies and sinking aggregates are characterized by steep concentration gradients of gases and nutrients in their interior...
October 2018: Science Advances
Jade d'Alpoim Guedes, R Kyle Bocinsky
Ancient farmers experienced climate change at the local level through variations in the yields of their staple crops. However, archaeologists have had difficulty in determining where, when, and how changes in climate affected ancient farmers. We model how several key transitions in temperature affected the productivity of six grain crops across Eurasia. Cooling events between 3750 and 3000 cal. BP lead humans in parts of the Tibetan Plateau and in Central Asia to diversify their crops. A second event at 2000 cal...
October 2018: Science Advances
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