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https://www.readbyqxmd.com/read/28821848/reconfiguration-of-quantum-states-in-formula-see-text-symmetric-quasi-one-dimensional-lattices
#1
Jung-Wan Ryu, Nojoon Myoung, Hee Chul Park
We demonstrate mesoscopic transport through quantum states in quasi-1D lattices maintaining the combination of parity and time-reversal symmetries by controlling energy gain and loss. We investigate the phase diagram of the non-Hermitian system where transitions take place between unbroken and broken [Formula: see text]-symmetric phases via exceptional points. Quantum transport in the lattice is measured only in the unbroken phases in the energy band-but not in the broken phases. The broken phase allows for spontaneous symmetry-broken states where the cross-stitch lattice is separated into two identical single lattices corresponding to conditionally degenerate eigenstates...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821823/highly-efficient-up-conversion-luminescence-in-er-3-yb-3-co-doped-na5lu9f32-single-crystals-by-vertical-bridgman-method
#2
Shinan He, Haiping Xia, Jianli Zhang, Yongsheng Zhu, Baojiu Chen
Er(3+)/Yb(3+) co-doped Na5Lu9F32 single crystals with different concentrations of Yb(3+) ions were prepared to investigate their phase structure, up-conversion (UC) properties and mechanism of UC luminescence by Bridgman method. Under 980 nm near-infrared (NIR) excitation, three sharp UC emission bands topping at green ~525 nm, ~548 nm and red ~669 nm were obtained in Er(3+)/Yb(3+) doped Na5Lu9F32 single crystals which are attributing to the transitions of (2)H11/2 → (4)I15/2, (4)S3/2 → (4)I15/2 and (4)F9/2 → (4)I15/2, respectively...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821785/machine-learning-quantum-phases-of-matter-beyond-the-fermion-sign-problem
#3
Peter Broecker, Juan Carrasquilla, Roger G Melko, Simon Trebst
State-of-the-art machine learning techniques promise to become a powerful tool in statistical mechanics via their capacity to distinguish different phases of matter in an automated way. Here we demonstrate that convolutional neural networks (CNN) can be optimized for quantum many-fermion systems such that they correctly identify and locate quantum phase transitions in such systems. Using auxiliary-field quantum Monte Carlo (QMC) simulations to sample the many-fermion system, we show that the Green's function holds sufficient information to allow for the distinction of different fermionic phases via a CNN...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821764/helical-edge-states-and-edge-state-transport-in-strained-armchair-graphene-nanoribbons
#4
Zheng-Fang Liu, Qing-Ping Wu, Ai-Xi Chen, Xian-Bo Xiao, Nian-Hua Liu, Guo-Xing Miao
A helical type edge state, which is generally supported only on graphene with zigzag boundaries, is found to also appear in armchair graphene nanoribbons in the presence of intrinsic spin-orbit coupling and a suitable strain. At a critical strain, there appears a quantum phase transition from a quantum spin Hall state to a trivial insulator state. Further investigation shows that the armchair graphene nanoribbons with intrinsic spin-orbit coupling, Rashba spin-orbit coupling, effective exchange fields and strains also support helical-like edge states with a unique spin texture...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821753/dynamic-reconfiguration-of-cortical-functional-connectivity-across-brain-states
#5
Iain Stitt, Karl J Hollensteiner, Edgar Galindo-Leon, Florian Pieper, Eva Fiedler, Thomas Stieglitz, Gerhard Engler, Guido Nolte, Andreas K Engel
Throughout each day, the brain displays transient changes in state, as evidenced by shifts in behavior and vigilance. While the electrophysiological correlates of brain states have been studied for some time, it remains unclear how large-scale cortico-cortical functional connectivity systematically reconfigures across states. Here, we investigate state-dependent shifts in cortical functional connectivity by recording local field potentials (LFPs) during spontaneous behavioral transitions in the ferret using chronically implanted micro-electrocorticographic (µECoG) arrays positioned over occipital, parietal, and temporal cortical regions...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28820532/topotactic-transition-of-%C3%AE-co-oh-2-to-%C3%AE-co-oh-2-anchored-on-coo-nanoparticles-during-electrochemical-water-oxidation-synergistic-electrocatalytic-effects
#6
Sumana Kundu, Bibhudatta Malik, Amrutha Prabhakaran, Deepak K Pattanayak, Vijayamohanan K Pillai
Herein, we report a single step, anionic surfactant-assisted, low temperature-hydrothermal synthetic strategy of CoO nanoparticles anchored on β-Co(OH)2 nanosheets which show a low overpotential (295 mV @ 10 mA cm(-2)) for the oxygen evolution reaction (OER). They also demonstrate much better kinetic parameters compared to the state-of-the-art RuO2. Interestingly, under the OER operational conditions (in alkaline medium), the topotactic transformation of α-Co(OH)2 to a stable Brucite-like β-Co(OH)2 phase leads to a synergistic interaction between the β-Co(OH)2 sheets on the CoO nanoparticles for enhancing the OER electrocatalytic activity...
August 18, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28820316/cell-cycle-related-metabolism-and-mitochondrial-dynamics-in-a-replication-competent-pancreatic-beta-cell-line
#7
Chiara Montemurro, Suryakiran Vadrevu, Tatyana Gurlo, Alexandra E Butler, Kenny E Vongbunyong, Anton Petcherski, Orian S Shirihai, Leslie S Satin, Daniel Braas, Peter C Butler, Slavica Tudzarova
Cell replication is a fundamental attribute of growth and repair in multicellular organisms. Pancreatic beta-cells in adults rarely enter cell cycle, hindering the capacity for regeneration in diabetes. Efforts to drive beta-cells into cell cycle have so far largely focused on regulatory molecules such as cyclins and cyclin-dependent kinases (CDKs). Investigations in cancer biology have uncovered that adaptive changes in metabolism, the mitochondrial network, and cellular Ca(2+) are critical for permitting cells to progress through the cell cycle...
August 18, 2017: Cell Cycle
https://www.readbyqxmd.com/read/28820216/criticality-of-the-phase-transition-on-stage-two-in-a-lattice-gas-model-of-a-graphite-anode-in-a-lithium-ion-battery
#8
E M Gavilán Arriazu, B A López de Mishima, O A Oviedo, E P M Leiva, O A Pinto
Herein, a Monte Carlo study within the canonical assembly has been applied to elucidate the lithium-ion phase transition order of a stage II lithium-graphite intercalation compound (LiC12) around the critical point. The results reveal a weakly first-order phase transition at 354.6 ± 0.5 K via measurements that follows the power laws with effective exponents. The graphite-lithium system was emulated within a lattice-gas model, comprising specific insertion sites arranged in four parallel planes with a triangular geometry...
August 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28819665/efficient-photoelectrochemical-water-splitting-on-ultrasmall-defect-rich-taox-nanoclusters-enhanced-by-size-selected-pt-nanocluster-promoters
#9
Saurabh Srivastava, Joseph Palathinkal Thomas, Nina Heinig, Marwa Abd-Ellah, Md Anisur Rahman, Kam Tong Leung
Formation of nanoclusters has attracted a lot of attention in recent years because of their distinct properties from isolated atoms and bulk solids. Here, we focus on the catalytic properties of supported transition metal oxide nanoclusters, such as TaO2, with a well-defined size distribution below 10 nm. We show that their catalytic performance can be greatly enhanced by introducing a reaction promoter such as Pt. Different combinations of precisely size-selected, defect-rich TaOx and Pt nanoclusters are produced by a gas-phase aggregation technique in a special DC magnetron sputtering system...
August 18, 2017: Nanoscale
https://www.readbyqxmd.com/read/28819662/chiral-amplification-of-disodium-cromoglycate-chromonics-induced-by-a-codeine-derivative
#10
F Berride, E Troche-Pesqueira, G Feio, E J Cabrita, T Sierra, A Navarro-Vázquez, M M Cid
Chromonic liquid crystals (CLC) are lyotropic phases formed by discotic mesogens in water. Simple chiral dopants such as amino acids have been reported to turn chromonic liquid crystals into their cholesteric counterparts. Here we report a chirality amplification effect in the nematic phase of a 9 wt% disodium cromoglycate (DSCG) lyotropic liquid crystal (LLC) upon doping with a water-soluble codeine derivative. The transition on cooling the isotropic to the nematic phase showed the presence of homochiral spindle-shaped droplets (tactoids)...
August 18, 2017: Soft Matter
https://www.readbyqxmd.com/read/28819640/slow-dynamics-of-electrons-at-a-metal-mott-insulator-boundary-in-an-organic-system-with-disorder
#11
Tetsuaki Itou, Eri Watanabe, Satoru Maegawa, Akiko Tajima, Naoya Tajima, Kazuya Kubo, Reizo Kato, Kazushi Kanoda
The Mott transition-a metal-insulator transition caused by repulsive Coulomb interactions between electrons-is a central issue in condensed matter physics because it is the mother earth of various attractive phenomena. Outstanding examples are high-Tc (critical temperature) cuprates and manganites exhibiting colossal magnetoresistance. Furthermore, spin liquid states, which are quantum-fluctuation-driven disordered ground states in antiferromagnets, have recently been found in magnetic systems very near the Mott transition...
August 2017: Science Advances
https://www.readbyqxmd.com/read/28819262/three-dimensional-imaging-of-vortex-structure-in-a-ferroelectric-nanoparticle-driven-by-an-electric-field
#12
D Karpov, Z Liu, T Dos Santos Rolo, R Harder, P V Balachandran, D Xue, T Lookman, E Fohtung
Topological defects of spontaneous polarization are extensively studied as templates for unique physical phenomena and in the design of reconfigurable electronic devices. Experimental investigations of the complex topologies of polarization have been limited to surface phenomena, which has restricted the probing of the dynamic volumetric domain morphology in operando. Here, we utilize Bragg coherent diffractive imaging of a single BaTiO3 nanoparticle in a composite polymer/ferroelectric capacitor to study the behavior of a three-dimensional vortex formed due to competing interactions involving ferroelectric domains...
August 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28819244/light-scattering-by-optically-trapped-vesicles-affords-unprecedented-temporal-resolution-of-lipid-raft-dynamics
#13
Liam Collard, David Perez-Guaita, Bayan H A Faraj, Bayden R Wood, Russell Wallis, Peter W Andrew, Andrew J Hudson
A spectroscopic technique is presented that is able to identify rapid changes in the bending modulus and fluidity of vesicle lipid bilayers on the micrometer scale, and distinguish between the presence and absence of heterogeneities in lipid-packing order. Individual unilamellar vesicles have been isolated using laser tweezers and, by measuring the intensity modulation of elastic back-scattered light, changes in the biophysical properties of lipid bilayers were revealed. Our approach offers unprecedented temporal resolution and, uniquely, physical transformations of lipid bilayers can be monitored on a length scale of micrometers...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28819172/suppression-for-an-intermediate-phase-in-znsb-films-by-nio-doping
#14
Chao Li, Guoxiang Wang, Dongfeng Qi, Daotian Shi, Xianghua Zhang, Hui Wang
The structural evolution and phase-change kinetics of NiO-doped ZnSb films are investigated. NiO-doped ZnSb films exhibit a single-step crystallization process, which is different from that of undoped ZnSb. NiO-doped ZnSb can directly crystallize into a stable ZnSb phase at temperatures greater than 320 °C with suppression of a metastable ZnSb phase. These characteristics enlarge the amorphous/crystalline resistance ratio by approximately five orders of magnitude. Moreover, NiO doping of ZnSb films increases crystallization temperature from 260 to 275 °C, improves data retention temperature from 201...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28818973/mutations-in-the-promoter-of-the-telomerase-gene-tert-contribute-to-tumorigenesis-by-a-two-step-mechanism
#15
Kunitoshi Chiba, Franziska K Lorbeer, A Hunter Shain, David T McSwiggen, Eva Schruf, Areum Oh, Jekwan Ryu, Xavier Darzacq, Boris C Bastian, Dirk Hockemeyer
TERT promoter mutations (TPMs) are the most common non-coding mutations in cancer. The timing and consequences of TPMs have not been fully established. Here we show that TPMs acquired at the transition from benign nevus to malignant melanoma do not support telomere maintenance. In vitro experiments revealed that TPMs do not prevent telomere attrition, resulting in cells with critically short and unprotected telomeres. Immortalization by TPMs requires a gradual upregulation of telomerase, coinciding with telomere fusions...
August 17, 2017: Science
https://www.readbyqxmd.com/read/28818940/two-dimensional-sp-2-carbon-conjugated-covalent-organic-frameworks
#16
Enquan Jin, Mizue Asada, Qing Xu, Sasanka Dalapati, Matthew A Addicoat, Michael A Brady, Hong Xu, Toshikazu Nakamura, Thomas Heine, Qiuhong Chen, Donglin Jiang
We synthesized a two-dimensional (2D) crystalline covalent organic framework (sp(2)c-COF) that was designed to be fully π-conjugated and constructed from all sp(2) carbons by C=C condensation reactions of tetrakis(4-formylphenyl)pyrene and 1,4-phenylenediacetonitrile. The C=C linkages topologically connect pyrene knots at regular intervals into a 2D lattice with π conjugations extended along both x and y directions and develop an eclipsed layer framework rather than the more conventionally obtained disordered structures...
August 18, 2017: Science
https://www.readbyqxmd.com/read/28818025/improvement-of-transition-metal-modified-activated-carbon-regeneration-by-h2o2-promoted-catalytic-wet-air-oxidation
#17
Imane Benhamed, Laurie Barthe, Rachid Kessas, Henri Delmas, Carine Julcour
Oxidative regeneration of activated carbon exhausted with phenolic compounds is still a challenging issue due to the frequent porosity loss. Addition of low H2O2 amount is investigated as a way to promote catalytic wet air oxidation (CWAO) of adsorbed pollutants and thereby to recover absorbent properties. Commercial activated carbon and transition metal (iron or copper) modified counterparts are tested in repeated adsorption / batch peroxide-promoted CWAO of phenol. Cycles are operated in both fixed bed and slurry reactors to vary the initial pollutant distribution in between the two phases...
August 18, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28817800/tia1-mutations-in-amyotrophic-lateral-sclerosis-and-frontotemporal-dementia-promote-phase-separation-and-alter-stress-granule-dynamics
#18
Ian R Mackenzie, Alexandra M Nicholson, Mohona Sarkar, James Messing, Maria D Purice, Cyril Pottier, Kavya Annu, Matt Baker, Ralph B Perkerson, Aishe Kurti, Billie J Matchett, Tanja Mittag, Jamshid Temirov, Ging-Yuek R Hsiung, Charles Krieger, Melissa E Murray, Masato Kato, John D Fryer, Leonard Petrucelli, Lorne Zinman, Sandra Weintraub, Marsel Mesulam, Julia Keith, Sasha A Zivkovic, Veronica Hirsch-Reinshagen, Raymond P Roos, Stephan Züchner, Neill R Graff-Radford, Ronald C Petersen, Richard J Caselli, Zbigniew K Wszolek, Elizabeth Finger, Carol Lippa, David Lacomis, Heather Stewart, Dennis W Dickson, Hong Joo Kim, Ekaterina Rogaeva, Eileen Bigio, Kevin B Boylan, J Paul Taylor, Rosa Rademakers
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are age-related neurodegenerative disorders with shared genetic etiologies and overlapping clinical and pathological features. Here we studied a novel ALS/FTD family and identified the P362L mutation in the low-complexity domain (LCD) of T cell-restricted intracellular antigen-1 (TIA1). Subsequent genetic association analyses showed an increased burden of TIA1 LCD mutations in ALS patients compared to controls (p = 8.7 × 10(-6)). Postmortem neuropathology of five TIA1 mutations carriers showed a consistent pathological signature with numerous round, hyaline, TAR DNA-binding protein 43 (TDP-43)-positive inclusions...
August 16, 2017: Neuron
https://www.readbyqxmd.com/read/28817711/on-chip-detection-of-gel-transition-temperature-using-a-novel-micro-thermomechanical-method
#19
Tsenguun Byambadorj, Erfan Dashtimoghadam, Mohamadali Malakoutian, Benyamin Davaji, Lobat Tayebi, James E Richie, Chung Hoon Lee
We present a new thermomechanical method and a platform to measure the phase transition temperature at microscale. A thin film metal sensor on a membrane simultaneously measures both temperature and mechanical strain of the sample during heating and cooling cycles. This thermomechanical principle of operation is described in detail. Physical hydrogel samples are prepared as a disc-shaped gels (200 μm thick and 1 mm diameter) and placed between an on-chip heater and sensor devices. The sol-gel transition temperature of gelatin solution at various concentrations, used as a model physical hydrogel, shows less than 3% deviation from in-depth rheological results...
2017: PloS One
https://www.readbyqxmd.com/read/28817580/criticality-predicts-maximum-irregularity-in-recurrent-networks-of-excitatory-nodes
#20
Yahya Karimipanah, Zhengyu Ma, Ralf Wessel
A rigorous understanding of brain dynamics and function requires a conceptual bridge between multiple levels of organization, including neural spiking and network-level population activity. Mounting evidence suggests that neural networks of cerebral cortex operate at a critical regime, which is defined as a transition point between two phases of short lasting and chaotic activity. However, despite the fact that criticality brings about certain functional advantages for information processing, its supporting evidence is still far from conclusive, as it has been mostly based on power law scaling of size and durations of cascades of activity...
2017: PloS One
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