bluuebunny/crossref_metadata_2025 huggingface dataset:
Bimetallic dimers adsorbed on a defect-free MgO(001) surface: bonding, structure and reactivity
Authors: Pašti Igor A. , Baljozović Miloš R. , Granda-Marulanda Laura P. , Skorodumova Natalia V.
Published: January 2015

Trends in bonding, electronic structure and reactivity of MgO-supported bimetallic dimers are analyzed using DFT calculations.
Influence of N-heteroaromatic π–π stacking on supramolecular assembly and coordination geometry; effect of a single-atom change in the ligand
Authors: Khavasi Hamid Reza , Mir Mohammad Sadegh Bahareh
Published: January 2015

A study on how the polarization of aromatic systems, through the introduction of a nitrogen heteroatom, affects the π–π interactions and crystal packing of mercury coordination compounds.
Inserted products of lithium silylquinolylamide dimers [{8-(2-R-C9H5N)N(Me3Si)}Li·OEt2]2 (R = H or Me) with dimethylcyanamide and their reactive derivatives with metal halides
Authors: Wang Peng , Li Haifen , Xue Xiaoyan , Chen Xia
Published: January 2015

Li, Ti, Fe and Co complexes bearing 8-quinolyl-linked guanidinate ligands have been synthesized and characterized. The structures of all complexes show various coordinative modes with the same multi-dentate ligands.
A label-free colorimetric sensor for Pb2+ detection based on the acceleration of gold leaching by graphene oxide
Authors: Shi Xinhao , Gu Wei , Zhang Cuiling , Zhao Longyun , Peng Weidong , Xian Yuezhong
Published: January 2015

In this work, we developed a novel, label-free, colorimetric sensor for Pb2+ detection based on the acceleration of gold leaching by graphene oxide (GO) at room temperature.
Amorphous calcium phosphate phase-mediated crystal nucleation kinetics and pathway
Authors: Jiang Shuqin , Pan Haihua , Chen Yan , Xu Xurong , Tang Ruikang
Published: January 2015

Generally, a solution nucleation model is used to study biomineralization kinetics. However, we found that the amorphous calcium phosphate (ACP)-mediated hydroxyapatite (HAP) nucleation in simulated body fluids (SBF) had a different profile from the linear relationship between ln J and ln−2 S (J, nucleation rate; S, supersaturation). This behaviour was alternatively explained by a developed heterogeneous nucleation theory, which indicated that HAP was nucleated at the ACP–solution interface via a polymorph transformation. Based upon this new model, we demonstrated experimentally that the embedded polymer molecules inside ACP were inert on HAP nucleation kinetics; rather, the polymers adsorbed on ACP surface could inhibit HAP nucleation from ACP. It further confirmed the heterogeneous nucleation pathway of HAP on the precursor phase. The present study provides an in-depth understanding of HAP formation for ACP-mediated crystallization.
Water corrosion of spent nuclear fuel: radiolysis driven dissolution at the UO2/water interface
Authors: Springell Ross , Rennie Sophie , Costelle Leila , Darnbrough James , Stitt Camilla , Cocklin Elizabeth , Lucas Chris , Burrows Robert , Sims Howard , Wermeille Didier , Rawle Jonathan , Nicklin Chris , Nuttall William , Scott Thomas , Lander Gerard
Published: January 2015

X-ray diffraction has been used to probe the radiolytic corrosion of uranium dioxide. Single crystal thin films of UO2 were exposed to an intense X-ray beam at a synchrotron source in the presence of water, in order to simultaneously provide radiation fields required to split the water into highly oxidising radiolytic products, and to probe the crystal structure and composition of the UO2 layer, and the morphology of the UO2/water interface. By modeling the electron density, surface roughness and layer thickness, we have been able to reproduce the observed reflectivity and diffraction profiles and detect changes in oxide composition and rate of dissolution at the Ångström level, over a timescale of several minutes. A finite element calculation of the highly oxidising hydrogen peroxide product suggests that a more complex surface interaction than simple reaction with H2O2 is responsible for an enhancement in the corrosion rate directly at the interface of water and UO2, and this may impact on models of long-term storage of spent nuclear fuel.
Single particle ICP-MS combined with a data evaluation tool as a routine technique for the analysis of nanoparticles in complex matrices
Authors: Peters Ruud , Herrera-Rivera Zahira , Undas Anna , van der Lee Martijn , Marvin Hans , Bouwmeester Hans , Weigel Stefan
Published: January 2015

spICP-MS measurement with a powerful data evaluation tool is presented as a fast, cost efficient and easy to use screening tool for metal and metal oxide NPs in complex matrices.
A cell-based sensor of fluid shear stress for microfluidics
Authors: Varma Sarvesh , Voldman Joel
Published: January 2015

We present a cell-based sensor embedded in NIH3T3 cells that fluoresces upon the application of fluid shear stress (FSS), as a simple and versatile method to assess the impact of various microsystem flow conditions on cell health.
Rhizobium leguminosarum HupE is a highly-specific diffusion facilitator for nickel uptake
Authors: Albareda Marta , Rodrigue Agnès , Brito Belén , Ruiz-Argüeso Tomás , Imperial Juan , Mandrand-Berthelot Marie-Andrée , Palacios Jose
Published: January 2015

Functional and topological analysis ofRhizobium leguminosarumHupE, the founding member of the HupE/UreJ family of nickel permeases, provides new hints on how bacteria manage nickel provision for metalloenzyme synthesis.
Ru(ii)–polypyridyl complex-grafted silica nanohybrids: versatile hybrid materials for Raman spectroscopy and photocatalysis
Authors: Vilvamani Narayanasamy , Gupta Rinkoo Devi , Awasthi Satish Kumar
Published: January 2015

Ru(ii)–polypyridyl complex-grafted silica nanohybrids were prepared with and without Ag NP cores, and these materials are demonstrated as substrates for plasmon-based on-resonance Raman scattering studies and as photocatalysts.
Microstructure and properties of carbon nanosheet/copper composites processed by particle-assisted shear exfoliation
Authors: Wang Lidong , Cui Ye , Yang Shuai , Li Bin , Liu Yuanyuan , Dong Pei , Bellah James , Fan Guohua , Vajtai Robert , Fei Weidong
Published: January 2015

Graphite was exfoliated to CNSs with the help of copper particles by going through the narrow gaps between the stator and rotor of the stator–rotor mixer.
Schisandrin A enhances the cytotoxicity of doxorubicin by the inhibition of nuclear factor-kappa B signaling in a doxorubicin-resistant human osteosarcoma cell line
Authors: Xia Yuan-Zheng , Yang Lei , Wang Zhen-Dong , Guo Chao , Zhang Chao , Geng Ya-Di , Kong Ling-Yi
Published: January 2015

Schisandrin A reversed chemoresistance in doxorubicin-induced MG-63 subline by inhibiting NF-kappaB-mediate expression of P-gp.
A highly sensitive and selective “turn-on” fluorescent probe for hypochlorous acid monitoring
Authors: Liao Ye-Xin , Wang Mao-Die , Li Kun , Yang Zhao-Xuan , Hou Ji-Ting , Wu Ming-Yu , Liu Yan-Hong , Yu Xiao-Qi
Published: January 2015

A highly sensitive and selective “turn-on” fluorescent probe was presented, which could selectively respond to hypochlorous acid over other ROS in aqueous solution.
The reaction kinetics and mechanism of crude fluoroelastomer vulcanized by direct fluorination with fluorine/nitrogen gas
Authors: Fan Cong , Li Baoyin , Ren Mengmeng , Wu Peng , Liu Yang , Chen Teng , Cheng Zheng , Qin Jiaqiang , Liu Xiangyang
Published: January 2015

The novel vulcanization of fluoroelastomer by fluorination is studied; moreover, the simultaneously accompanied fluorine content increases and tribological property is improved.
Targeted dextran-b-poly(ε-caprolactone) micelles for cancer treatments
Authors: Zhang Zhe , Chen Xiaofei , Gao Xiaoye , Yao Xuemei , Chen Li , He Chaoliang , Chen Xuesi
Published: January 2015

In this study, targeted amphiphilic dextran-b-poly(ε-caprolactone) (Dex-PCL) was synthesized and used for efficient intracellular drug delivery.
AIE-active mechanochromic materials based N-phenylcarbazol-substituted tetraarylethene for OLED applications
Authors: Zhao He , Wang Yang , Wang Yongtao , He Gufeng , Xue Mei , Guo Pingan , Dai Bin , Liu Zhiyong , Qi Yu
Published: January 2015

Well-designed AIE-active luminogens as both hole-transporting and light-emitting layer materials can be utilized to fabricate metal free and nondoped OLEDs.
Transition metal induced switch of fluorescence and absorption response of a Zn(ii)porphyrin–DNA conjugate to cysteine derivatives
Authors: Choi Jung Kyu , Sargsyan Gevorg , Johnson Breiana D. , Balaz Milan
Published: January 2015

We report a supramolecular zinc(ii)porphyrin–oligothymidine/metal ion complex as a dual highly sensitive optical probe of biothiols with switchable spectroscopic signals.
Cu(OTf)2 catalyzed three component strategy for the synthesis of thienopyridine containing spirooxindoles and their cytotoxic evaluation
Authors: Parthasarathy K. , Praveen C. , Kumar P. Senthil , Balachandran C. , Perumal P. T.
Published: January 2015

Compound 5v docked in caspase-3 (−10.5 kcal mol−1).
Pyridinyl functionalized MCM-48 supported highly active heterogeneous palladium catalyst for cross-coupling reactions
Authors: Sarkar Shaheen M. , Rahman Md. Lutfor , Yusoff Mashitah Mohd
Published: January 2015

Pyridinyl functionalized MCM-48-supported Pd-catalyst efficiently (0.013–0.025 mol%) promoted Heck, Suzuki and Sonogashira cross-coupling reactions. Moreover, the catalyst was reused five times without significant loss of its activity.
Synthesis and biological evaluation of peptidomimetics containing the tryptamine moiety as a potential antitumor agent
Authors: Wang Xiaohui , Su Haihuan , Chen Changshui , Cao Xiufang
Published: January 2015

A series of novel peptidomimetics bearing tryptamine moiety were designed, synthesized, and evaluated for their inhibition activities against cell proliferation (HepG2, Huh-7, A875 and BEL-7402/5-FU cell lines).
A facile label-free colorimetric aptasensor for ricin based on the peroxidase-like activity of gold nanoparticles
Authors: Hu Jingting , Ni Pengjuan , Dai Haichao , Sun Yujing , Wang Yilin , Jiang Shu , Li Zhuang
Published: January 2015

A facile colorimetric aptasensor for ricin based on the peroxidase-like activity of gold nanoparticles was demonstrated for the first time.
Functionalized graphene-based biomimetic microsensor interfacing with living cells to sensitively monitor nitric oxide release
Authors: Liu Yan-Ling , Wang Xue-Ying , Xu Jia-Quan , Xiao Chong , Liu Yan-Hong , Zhang Xin-Wei , Liu Jun-Tao , Huang Wei-Hua
Published: January 2015

We present a biomimetic and reusable microsensor with sub-nanomolar sensitivity by elaboratly functionalizing graphene for monitoring NO release in real-time.
Atomistic simulation for coil-to-globule transition of poly(2-dimethylaminoethyl methacrylate)
Authors: Min Sa Hoon , Kwak Sang Kyu , Kim Byeong-Su
Published: January 2015

We investigate the coil-to-globule transition of poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) in the aqueous solution through the lower critical solution temperature (LCST) by atomistic molecular dynamics (MD) simulations.
Electrochemical properties and morphological evolution of pitaya-like Sb@C microspheres as high-performance anode for sodium ion batteries
Authors: Wu Lin , Lu Haiyan , Xiao Lifen , Ai Xinping , Yang Hanxi , Cao Yuliang
Published: January 2015

Pitaya-like Sb@C microspheres are prepared successfullyviaa facile aerosol spray drying method, which present a high initial capacity, good capacity retention and high rate capability for Na-ion storage. Morphological evolution reveals that the maintenance of the pitaya-like configuration guarantees excellent electrochemical performance.
Understanding the composition and electronic structure dependent photocatalytic performance of bismuth oxyiodides
Authors: Long Mingce , Hu Peidong , Wu Haodong , Chen Yuanyuan , Tan Beihui , Cai Weimin
Published: January 2015

Iodine vacancies in bismuth oxyiodides generated by calcination contribute to the increased band gaps and more anodic valance band potentials. The efficient photocatalytic activity when calcined at 400 °C is attributed to both iodine vacancies and heterojunctions.
(100) surface-exposed CeO2nanocubes as an efficient heterogeneous catalyst in the tandem oxidation of benzyl alcohol, para-chlorobenzyl alcohol and toluene to the corresponding aldehydes selectively
Authors: Deori Kalyanjyoti , Kalita Chinmoy , Deka Sasanka
Published: January 2015

Efficient oxidation of aromatic alcohols and toluene to the corresponding aldehydes was achieved selectively by an active-surface-exposed CeO2nanocube heterogeneous catalyst.
Broadband enhanced fluorescence using zinc-oxide nanoflower arrays
Authors: Wang Tiesheng , Costan Jozerd , Centeno Anthony , Pang Jing S. , Darvill Daniel , Ryan Mary P. , Xie Fang
Published: January 2015

ZnO nanoflower arrays have significantly higher fluorescence enhancement than ZnO nanorod arrays, with broadband enhancement capability.
Iron catalyzed halogenation of benzylic aldehydes and ketones
Authors: Savela Risto , Wärnå Johan , Murzin Dmitry Yu. , Leino Reko
Published: January 2015

A simple iron-catalyzed method for halogenation of aromatic carbonyl compounds in one step has been developed, combined with mechanistic investigation.
Correction: A novel enantioselective synthesis of 6H-dibenzopyran derivatives by combined palladium/norbornene and cinchona alkaloid catalysis
Authors: Xu Di , Dai Li , Catellani Marta , Motti Elena , Della Ca’ Nicola , Zhou Zhiming
Published: January 2015

Correction for ‘A novel enantioselective synthesis of 6H-dibenzopyran derivatives by combined palladium/norbornene and cinchona alkaloid catalysis’ by Di Xu et al., Org. Biomol. Chem., 2015, DOI: 10.1039/c4ob02551b.
Phase transformations in binary colloidal monolayers
Authors: Yang Ye , Fu Lin , Marcoux Catherine , Socolar Joshua E. S. , Charbonneau Patrick , Yellen Benjamin B.
Published: January 2015

We have developed a magnetic colloidal system allowing for direct observations of crystal transformations in a binary alloy. Distinct modes for passing from a square checkerboard to a striped phase are observed for different orientations of the applied in-plane field relative to the crystal axes.
Ultrasoft, highly deformable microgels
Authors: Bachman Haylee , Brown Ashley C. , Clarke Kimberly C. , Dhada Kabir S. , Douglas Alison , Hansen Caroline E. , Herman Emily , Hyatt John S. , Kodlekere Purva , Meng Zhiyong , Saxena Shalini , Spears Jr Mark W. , Welsch Nicole , Lyon L. Andrew
Published: January 2015

PNIPAm microgels formed under crosslinker free conditions are soft and highly deformable.
Water confined in self-assembled ionic surfactant nano-structures
Authors: Hanot Samuel , Lyonnard Sandrine , Mossa Stefano
Published: January 2015

We present a coarse-grained model for ionic surfactants in explicit aqueous solutions, and study by computer simulation both the impact of water content on the morphology of the system, and the consequent effect of the formed interfaces on the structural features of the absorbed fluid.
Functionalized layered double hydroxide-based epoxy nanocomposites with improved flame retardancy and mechanical properties
Authors: Kalali Ehsan Naderi , Wang Xin , Wang De-Yi
Published: January 2015

Aiming at developing highly efficient nano fire retardants and fire retarding epoxy resins, a series of functionalized layered double hydroxides (LDHs) based on a multi-modifier system have been developed. These functionalized LDHs were used as novel nano flame-retardants for bisphenol epoxy resins and compared with unmodified LDHs.
M‐sequence‐based ultra‐wideband sensor network for vitality monitoring of elders at home
Authors: Sachs Jürgen , Herrmann Ralf
Published: January 2015

The western societies are increasingly faced with the challenges of enabling a self‐determined and safe life for a growing number of elderly people. Remote monitoring of vitality is an important tool for health risk mitigation but many of the current methods either deliver only infrequent information or require conscious cooperation of the senior. The authors propose an ultra‐wideband (UWB) radio sensor network based on M‐sequence technology specifically designed for the vitality monitoring of persons living alone. It uses the frequency band in the range from 6 to 8.5 GHz (electronic communications committee (ECC)‐band), and provides precise localisation, captures breathing motion during rests, can be used for fall detection and allows the extraction of gait features. The sensor network can be installed in common living spaces. It operates continuously in the background without any user interaction. Vitality monitoring by radar sensors is based on motion detection and tracking. This poses some challenges to radar devices because of the harsh multi‐path conditions in apartments. This study discusses these challenges, illustrates how to meet them and gives examples for vitality features which can be extracted from UWB‐radar data.
A home-made system for IPCE measurement of standard and dye-sensitized solar cells
Authors: Palma Giuseppina , Cozzarini Luca , Capria Ennio , Fraleoni-Morgera Alessandro
Published: January 2015

A home-made system for incident photon-to-electron conversion efficiency (IPCE) characterization, based on a double-beam UV-Vis spectrophotometer, has been set up. In addition to its low cost (compared to the commercially available apparatuses), the double-beam configuration gives the advantage to measure, autonomously and with no need for supplementary equipment, the lamp power in real time, compensating possible variations of the spectral emission intensity and quality, thus reducing measurement times. To manage the optical and electronic components of the system, a custom software has been developed. Validations carried out on a common silicon-based photodiode and on a dye-sensitized solar cell confirm the possibility to adopt this system for determining the IPCE of solar cells, including dye-sensitized ones.
Liquid–liquid equilibria for soft-repulsive particles: Improved equation of state and methodology for representing molecules of different sizes and chemistry in dissipative particle dynamics
Authors: Liyana-Arachchi Thilanga P. , Jamadagni Sumanth N. , Eike David , Koenig Peter H. , Siepmann J. Ilja
Published: January 2015

Three developments are presented that significantly expand the applicability of dissipative particle dynamics (DPD) simulations for symmetric and non-symmetric mixtures, where the former contain particles with equal repulsive parameter for self-interactions but a different repulsive parameter for cross-interactions, and the latter contain particles with different repulsive parameters also for the self-interactions. Monte Carlo and molecular dynamics simulations for unary phases covering a wide range of repulsive parameters and of densities for single-bead DPD particles point to deficiencies of the Groot and Warren equation of state (GW-EOS) [J. Chem. Phys. 107, 4423 (1997)]. A revised version, called rGW-EOS, is proposed here that is significantly more accurate over a wider range of parameters/densities. The second development is the generalization of the relationship between the Flory-Huggins χ parameter and the repulsive cross-interaction parameter when the two particles involved have different molecular volumes. The third aspect is an investigation of Gibbs ensemble Monte Carlo simulation protocols, which demonstrates the importance of volume fluctuations and excess volumes of mixing even for equimolar symmetric mixtures of DPD particles. As an illustrative example, the novel DPD methodology is applied to the prediction of the liquid–liquid equilibria for acetic anhydride/(n-hexane or n-octane) binary mixtures.
Energy and temperature dependent dissociation of the Na+(benzene)1,2 clusters: Importance of anharmonicity
Authors: Kolakkandy Sujitha , Paul Amit K. , Pratihar Subha , Kohale Swapnil C. , Barnes George L. , Wang Hai , Hase William L.
Published: January 2015

Chemical dynamics simulations were performed to study the unimolecular dissociation of randomly excited Na+(Bz) and Na+(Bz)2 clusters; Bz = benzene. The simulations were performed at constant energy, and temperatures in the range of 1200–2200 K relevant to combustion, using an analytic potential energy surface (PES) derived in part from MP2/6-311+G* calculations. The clusters decompose with exponential probabilities, consistent with RRKM unimolecular rate theory. Analyses show that intramolecular vibrational energy redistribution is sufficiently rapid within the clusters that their unimolecular dynamics is intrinsically RRKM. Arrhenius parameters, determined from the simulations of the clusters, are unusual in that Ea is ∼10 kcal/mol lower the Na+(Bz) → Na+ + Bz dissociation energy and the A-factor is approximately two orders-of-magnitude too small. Analyses indicate that temperature dependent anharmonicity is important for the Na+(Bz) cluster’s unimolecular rate constants k(T). This is consistent with the temperature dependent anharmonicity found for the Na+(Bz) cluster from a Monte Carlo calculation based on the analytic PES used for the simulations. Apparently temperature dependent anharmonicity is quite important for unimolecular dissociation of the Na+(Bz)1,2 clusters.
Model-free estimation of the effective correlation time for C–H bond reorientation in amphiphilic bilayers: 1H–13C solid-state NMR and MD simulations
Authors: Ferreira Tiago Mendes , Ollila O. H. Samuli , Pigliapochi Roberta , Dabkowska Aleksandra P. , Topgaard Daniel
Published: January 2015

Molecular dynamics (MD) simulations give atomically detailed information on structure and dynamics in amphiphilic bilayer systems on timescales up to about 1 μs. The reorientational dynamics of the C–H bonds is conventionally verified by measurements of 13C or 2H nuclear magnetic resonance (NMR) longitudinal relaxation rates R1, which are more sensitive to motional processes with correlation times close to the inverse Larmor frequency, typically around 1-10 ns on standard NMR instrumentation, and are thus less sensitive to the 10-1000 ns timescale motion that can be observed in the MD simulations. We propose an experimental procedure for atomically resolved model-free estimation of the C–H bond effective reorientational correlation time τe, which includes contributions from the entire range of all-atom MD timescales and that can be calculated directly from the MD trajectories. The approach is based on measurements of 13C R1 and R1ρ relaxation rates, as well as 1H−13C dipolar couplings, and is applicable to anisotropic liquid crystalline lipid or surfactant systems using a conventional solid-state NMR spectrometer and samples with natural isotopic composition. The procedure is demonstrated on a fully hydrated lamellar phase of 1-palmitoyl-2-oleoyl-phosphatidylcholine, yielding values of τe from 0.1 ns for the methyl groups in the choline moiety and at the end of the acyl chains to 3 ns for the g1 methylene group of the glycerol backbone. MD simulations performed with a widely used united-atom force-field reproduce the τe-profile of the major part of the acyl chains but underestimate the dynamics of the glycerol backbone and adjacent molecular segments. The measurement of experimental τe-profiles can be used to study subtle effects on C–H bond reorientational motions in anisotropic liquid crystals, as well as to validate the C–H bond reorientation dynamics predicted in MD simulations of amphiphilic bilayers such as lipid membranes.
Mean ionic activity coefficients in aqueous NaCl solutions from molecular dynamics simulations
Authors: Mester Zoltan , Panagiotopoulos Athanassios Z.
Published: January 2015

The mean ionic activity coefficients of aqueous NaCl solutions of varying concentrations at 298.15 K and 1 bar have been obtained from molecular dynamics simulations by gradually turning on the interactions of an ion pair inserted into the solution. Several common non-polarizable water and ion models have been used in the simulations. Gibbs-Duhem equation calculations of the thermodynamic activity of water are used to confirm the thermodynamic consistency of the mean ionic activity coefficients. While the majority of model combinations predict the correct trends in mean ionic activity coefficients, they overestimate their values at high salt concentrations. The solubility predictions also suffer from inaccuracies, with all models underpredicting the experimental values, some by large factors. These results point to the need for further ion and water model development.
Nanoscale strain distributions in embedded SiGe semiconductor devices revealed by precession electron diffraction and dual lens dark field electron holography
Authors: Wang Y. Y. , Cooper D. , Rouviere J. , Murray C. E. , Bernier N. , Bruley J.
Published: January 2015

The detailed strain distributions produced by embedded SiGe stressor structures are measured at high spatial resolution with high precision, with dual lens dark field electron holography and precession electron diffraction. Shear strain and lattice rotation within the crystalline lattice are observed at the boundaries between the SiGe and Si regions. The experimental results are compared to micromechanical modeling simulations to understand the mechanisms of elastic relaxation on all the modes of deformation at a sub-micron length scale.
The segmental and chain relaxation modes in high-cis-polyisoprene as studied by thermally stimulated currents
Authors: Mora Elsa , Brás Ana R. , Pyckhout-Hintzen Wim , Diogo Hermínio P. , Moura Ramos Joaquim J.
Published: January 2015

The technique of Thermally Stimulated Currents is used to study the slow molecular mobility in a series of poly (1,4-cis-isoprene) samples with different molecular weights, Mw, and low polydispersity. The technique revealed a high resolution power, particularly useful in the study of the lower molecular weight samples where the chain and the segmental relaxations strongly overlap. The dynamic crossover that is reported for the normal mode by varying the molecular weight is clearly revealed by the thermally stimulated depolarization currents results through the temperature location, TMn, of the normal mode peak, the values of the relaxation time at TMn, τ(TMn), and the value of the fragility index of the normal mode, mn. The kinetic features of the glass transition relaxation of polyisoprene have also been determined.
Interactions between ring polymers in dilute solution studied by Monte Carlo simulation
Authors: Suzuki Jiro , Takano Atsushi , Matsushita Yushu
Published: January 2015

The second virial coefficient, A2, for trivial-ring polymers in dilute condition was estimated from a Metropolis Monte Carlo (MC) simulation, and the temperature dependence of A2 has been discussed with their Flory’s scaling exponent, ν, in Rg ∝ Nν, where Rg is radius of gyration of a polymer molecule. A limited but not too small number of polymer molecules were employed in the simulation, and the A2 values at various temperatures were calculated from the molecular density fluctuation in the solution. In the simulation, the topology of ring polymers was kept, since chain crossing was prohibited. The excluded volume effects can be screened by the attractive force between segments, which depends on the temperature, Tα, defined in the Metropolis MC method. Linear and trivial-ring polymers have the ν value of 1/2 at Tα = 10.605 and 10.504. At Tα = 10.504, the excluded volume effects are screened by the attractive force generated between segments in a ring polymer, but the A2 value for ring polymers is positive. Thus, the temperature at A2 = 0 for a ring polymer is lower than that at ν = 1/2, and this fact can be explained with the following two reasons. (a) Rg value for a ring polymer is much smaller than that for a linear polymer at the same temperature and molecular weight, where interpenetration of a ring polymer chain into neighboring chains is apparently less than a linear chain. (b) The conformation of trivial rings can be statistically described as a closed random walk at ν = 1/2, but their topologies are kept, being produced topological constraints, which strongly relate not only to the long-distance interaction between segments in a molecule but also the inter-molecular interaction.
Stacking-dependent shear modes in trilayer graphene
Authors: Lui Chun Hung , Ye Zhipeng , Keiser Courtney , Barros Eduardo B. , He Rui
Published: January 2015

We observe distinct interlayer shear mode Raman spectra for trilayer graphene with ABA and ABC stacking order. There are two rigid-plane shear-mode phonon branches in trilayer graphene. We find that ABA trilayers exhibit pronounced Raman response from the high-frequency shear branch, without any noticeable response from the low-frequency branch. In contrast, ABC trilayers exhibit no response from the high-frequency shear branch, but significant Raman response from the low-frequency branch. Such complementary behaviors of Raman shear modes can be explained by the distinct symmetry of the two trilayer allotropes. The strong stacking-order dependence is not found in the layer-breathing modes, and thus represents a unique characteristic of the shear modes.
Large E-field tunability of magnetic anisotropy and ferromagnetic resonance frequency of co-sputtered Fe50Co50-B film
Authors: Li Shandong , Xue Qian , Du Honglei , Xu Jie , Li Qiang , Shi Zhipeng , Gao Xiaoyang , Liu Ming , Nan Tianxiang , Hu Zhongqiang , Sun Nian X. , Shao Weiquan
Published: January 2015

Fe27.45Co30.19B42.36 (referred to as FeCoB) films with 100 nm in thickness were co-sputtered on (011)-cut lead zinc niobate-lead titanate (PZN-PT) single crystal substrate under RF powers of 80 W for Fe50Co50 target and 120 W for B target, respectively. The anisotropy field HK of the FeCoB/PZN-PT multiferroic composite is increased by more than 10 times, from 56 to 663 Oe under the E-field from 0 to 7 kV/cm due to the strong magnetoelectric coupling, corresponding to a large tunability of HK of 86.7 Oe cm/kV. At the same time, the self-bias ferromagnetic resonance frequency fFMR is dramatically shifted upwards by an electric field from 2.57 to 9.02 GHz with an increment of 6.45 GHz, corresponding to E-field tunablity of fFMR 921.4 MHz.cm/kV. These features demonstrate that FeCoB/PZN-PT multiferroic laminates prepared under an integrated circuits process are promising in fabrication of E-field tunable monolithic microwave integrated circuits (MMIC) devices and their components.
Fabrication of MgAl2O4 tunnel barrier by radio frequency-sputtering method and magnetoresistance effect through it with Fe or Fe4N ferromagnetic electrode
Authors: Tsunoda Masakiyo , Chiba Ryoichi , Kabara Kazuki
Published: January 2015

Spinel MgAl2O4 thin films were deposited on MgO single-crystal substrates and epitaxial Fe (or Fe4N) thin films by RF-sputtering from a ceramic target. Epitaxial relationship was confirmed by X-ray diffraction analysis between the crystalline spinel MgAl2O4 films and the respective substrate and underlayers, while no diffraction peak was observed from the films deposited on amorphous substrates. Spin-valve type magnetic tunnel junctions (MTJs) with a stacking structure of Fe [Fe4N]/MgAl2O4/CoFeB/Ru/Fe/MnIr exhibited normal [inverse] tunnel magnetoresistance (TMR) effect, reflecting the sign of spin polarization of Fe [Fe4N]. The maximum magnitude of the TMR ratio obtained for the Fe-based and Fe4N-based MTJs was 67% and 18%, respectively. The resistance area product values of the MTJs were significantly larger than the reported values for the MTJs with a post-oxidized spinel MgAl2O4 barrier.
Hybrid absorbers composed of Fe3O4 thin film and magnetic composite sheet and enhancement of conduction noise absorption on a microstrip line
Authors: Kim Sung-Soo
Published: January 2015

In response to develop wide-band noise absorbers with an improved low-frequency performance, this study investigates hybrid absorbers that are composed of conductive Fe3O4 thin film and magnetic composite sheets. The Fe3O4 films prepared via reactive sputtering exhibit a typical value of electrical resistivity of ≃10−4 Ωm. Rubber composites with flaky Fe-Si-Al particles of a high permeability and high permittivity are used as the magnetic sheet functioning as an electromagnetic shield barrier. Microstrip lines with a characteristic impedance of 50 Ω are used to measure the noise absorbing properties. For the Fe3O4 film with a low surface resistance and covered by the magnetic sheet, approximately 80% power absorption can be obtained at 1 GHz, which is significantly higher than that of the original magnetic sheet or Fe3O4 film. The high power absorption of the hybrid absorber is attributed to the enhanced ohmic loss of the Fe3O4 film through increased electric field strength bounded by the upper magnetic composite sheet. The noise absorption is further enhanced through increasing the electrical conductivity of the film containing more conductive phase (Fe3O4 + Fe), which can be prepared in a reduced oxygen partial pressure during reactive sputtering.
Induced-charge electrokinetics in a conducting nanochannel with broken geometric symmetry: Towards a flexible control of ionic transport
Authors: Zhao Cunlu , Song Yongxin , Yang Chun
Published: January 2015

In the literature, conventional electrokinetics is widely used as a principle of operating nanofluidic devices. Different from the conventional electrokinetics involving nonpolarizable solid surfaces with fixed surface charge, induced-charge electrokinetic (ICEK) phenomena deal with polarizable surfaces with the ability of surface charge modulation through electric polarization under external electric fields. Because of several advantages, ICEK phenomena have drawn a great deal of attention in microfluidic community. Herein, we propose the first effort of extending the ICEK phenomena from microfluidics to nanofluidics. In particular, we report a numerical model for the ICEK phenomena in a tapered nanochannel with conducting (ideally polarizable) walls. It is shown that due to the broken geometric symmetry of the nanochannel, induced-charge electroosmotic flow inside the nanochannel exhibits a flow rectification such that electrolyte solution always flows from the narrow end of the nanochannel to the wide end for either a forward electric bias (electric field from the narrow to wide ends) or a reverse electric bias (electric field from the wide to narrow ends). In addition, we demonstrate that the ion selectivity of such tapered conducting nanochannel can be actively tuned to be cation-selective with a forward bias and anion-selective with a reverse bias. Promisingly, conducting nanochannels with broken geometric symmetry could be potentially used for constructing nanofluidic pumps with the unidirectional pumping capacity and ion selectors with the tuneable ionic selection.
Universal formalism of Fano resonance
Authors: Huang Liang , Lai Ying-Cheng , Luo Hong-Gang , Grebogi Celso
Published: January 2015

The phenomenon of Fano resonance is ubiquitous in a large variety of wave scattering systems, where the resonance profile is typically asymmetric. Whether the parameter characterizing the asymmetry should be complex or real is an issue of great experimental interest. Using coherent quantum transport as a paradigm and taking into account of the collective contribution from all available scattering channels, we derive a universal formula for the Fano-resonance profile. We show that our formula bridges naturally the traditional Fano formulas with complex and real asymmetry parameters, indicating that the two types of formulas are fundamentally equivalent (except for an offset). The connection also reveals a clear footprint for the conductance resonance during a dephasing process. Therefore, the emergence of complex asymmetric parameter when fitting with experimental data needs to be properly interpreted. Furthermore, we have provided a theory for the width of the resonance, which relates explicitly the width to the degree of localization of the close-by eigenstates and the corresponding coupling matrices or the self-energies caused by the leads. Our work not only resolves the issue about the nature of the asymmetry parameter, but also provides deeper physical insights into the origin of Fano resonance. Since the only assumption in our treatment is that the transport can be described by the Green’s function formalism, our results are also valid for broad disciplines including scattering problems of electromagnetic waves, acoustics, and seismology.
Response of a flexible filament in a flowing soap film subject to a forced vibration
Authors: Jia Laibing , Xiao Qing , Wu Haijun , Wu Yanfeng , Yin Xiezhen
Published: January 2015

The interactions between flexible plates and fluids are important physical phenomena. A flag in wind is one of the most simplified and classical models for studying the problem. In this paper, we investigated the response of a flag in flow with an externally forced vibration by using flexible filaments and soap film. Experiments show that for a filament that is either in oscillation or stationary, the external forced vibration leads to its oscillation. A synchronization phenomenon occurs in the experiments. A small perturbation leads to a large response of flapping amplitude in response. The insight provided here is helpful to the applications in the flow control, energy harvesting, and bionic propulsion areas.
Mushroom plasmonic metamaterial infrared absorbers
Authors: Ogawa Shinpei , Fujisawa Daisuke , Hata Hisatoshi , Uetsuki Mitsuharu , Misaki Koji , Kimata Masafumi
Published: January 2015

There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF2 etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.
High-Q silicon carbide photonic-crystal cavities
Authors: Lee Jonathan Y. , Lu Xiyuan , Lin Qiang
Published: January 2015

We demonstrate one-dimensional photonic-crystal nanobeam cavities in amorphous silicon carbide. The fundamental mode exhibits intrinsic optical quality factor as high as 7.69 × 104 with mode volume ∼0.60(λ/n)3 at wavelength 1.5 μm. A corresponding Purcell factor value of ∼104 is the highest reported to date in silicon carbide optical cavities. The device exhibits great potential for integrated nonlinear photonics and cavity nano-optomechanics.
Modeling the conductivity around the dimensionality-controlled metal-insulator transition in LaNiO3/LaAlO3 (100) superlattices
Authors: Wei Haoming , Jenderka Marcus , Bonholzer Michael , Grundmann Marius , Lorenz Michael
Published: January 2015

A dimensionality controlled metal insulator transition in epitaxial [LaNiO3 (d nm)/LaAlO3(2 nm)]10 (100) superlattices (thereafter [d/2]10 SLs) is demonstrated for decreasing LaNiO3 single layer thickness from 4 nm down to 1.2 nm. The [4/2]10 SL shows metallic behavior with positive resistivity temperature coefficient, while the [2/2]10 SL shows a metal-insulator transition with crossover from 3D to two-dimensional single-layer dimensionality. Strong localization appears for the [1.2/2]10 SL with the resistivity being dominated by two-dimensional variable range hopping with a localization length of about 0.035 nm.
Properties of a finite fully spin-polarized free homogeneous one-dimensional electron gas
Authors: Ciftja Orion
Published: January 2015

The homogeneous electron gas model has been quite successful to predict the bulk properties of systems of electrons at various densities. In many occasions, a simplified free homogeneous electron gas model represents a powerful first approximation to a real system. Despite our considerable knowledge on the bulk properties of a homogeneous electron gas, advances in nanoscience and nanotechnology call for a greater effort to understand the opposite limit of small finite systems of electrons with size-dependent properties. In this work, we provide a detailed description of the properties of a finite fully spin-polarized (spinless) free homogeneous one-dimensional electron gas, the simplest of the free homogeneous electron gases. We derive exact analytical results for various quantities such as the one-particle density function, two-particle density function, one-particle density matrix, pair correlation function and energy of finite systems with an arbitrary number of electrons. The results obtained provide a detailed view on how various quantities corresponding to a finite system approach their bulk (thermodynamic limit) value.
Treatment of Hypertensive Patients With Diabetes and Microalbuminuria With Combination Indapamide SR/Amlodipine: Retrospective Analysis of NESTOR
Authors: Hanon Olivier , Boully Clemence , Caillard Laure , Labourée Florian , Cochiello Sophie , Chaussade Edouard
Published: January 2015

BACKGROUND

Combination treatments for hypertension most often include a renin–angiotensin–aldosterone system (RAAS) inhibitor. However, systolic blood pressure (SBP) remains difficult to control. Non-RAAS-inhibiting strategies such as calcium channel blocker/thiazide-like diuretic combinations may offer effective alternatives.

METHODS

Hypertensive diabetic patients with microalbuminuria were included in this retrospective, post-hoc analysis of the Natrilix SR Versus Enalapril Study in Hypertensive Type 2 Diabetics With MicrOalbuminuRia (NESTOR) trial if they were uncontrolled on monotherapy (indapamide slow release (SR) 1.5mg or enalapril 10mg) and had been given add-on amlodipine 5mg. Patients uncontrolled with monotherapy/amlodipine 5mg were uptitrated to 10mg.

RESULTS

After 52 weeks, supine SBP/diastolic BP (DBP) decreased from baseline by 26±13/14±9mm Hg in the indapamide SR/amlodipine group (n = 135) and by 21±14/11±9mm Hg in the enalapril/amlodipine group (n = 156) (P = 0.006 for ΔSBP). In the amlodipine 10mg subgroup, SBP/DBP decreased from baseline by 26±13/13±9mm Hg in the indapamide SR/amlodipine group (n = 62) and by 20±13/12±8mm Hg in the enalapril/amlodipine group (n = 77) (P = 0.02 for ΔSBP). Treatment with indapamide SR/amlodipine was well tolerated. Few patients experienced edema, with no between-group differences. As expected with diuretics, slight changes in kalemia and in uricemia were observed in the indapamide SR/amlodipine group. Changes in fasting glucose, lipids, natremia, and creatinine clearance were similar between groups.

CONCLUSIONS

Indapamide SR/amlodipine results in superior SBP reduction with a safety profile in line with that of its components and tolerability equivalent to that of an angiotensin-converting enzyme inhibitor/amlodipine strategy.
Human regulator of telomere elongation helicase 1 (RTEL1) is required for the nuclear and cytoplasmic trafficking of pre-U2 RNA
Authors: Schertzer Michael , Jouravleva Karina , Perderiset Mylene , Dingli Florent , Loew Damarys , Le Guen Tangui , Bardoni Barbara , de Villartay Jean-Pierre , Revy Patrick , Londoño-Vallejo Arturo
Published: January 2015

Hoyeraal-Hreidarsson syndrome (HHS) is a severe form of Dyskeratosis congenita characterized by developmental defects, bone marrow failure and immunodeficiency and has been associated with telomere dysfunction. Recently, mutations in Regulator of Telomere ELongation helicase 1 (RTEL1), a helicase first identified in Mus musculus as being responsible for the maintenance of long telomeres, have been identified in several HHS patients. Here we show that RTEL1 is required for the export and the correct cytoplasmic trafficking of the small nuclear (sn) RNA pre-U2, a component of the major spliceosome complex. RTEL1-HHS cells show abnormal subcellular partitioning of pre-U2, defects in the recycling of ribonucleotide proteins (RNP) in the cytoplasm and splicing defects. While most of these phenotypes can be suppressed by re-expressing the wild-type protein in RTEL1-HHS cells, expression of RTEL1 mutated variants in immortalized cells provokes cytoplasmic mislocalizations of pre-U2 and other RNP components, as well as splicing defects, thus phenocopying RTEL1-HHS cellular defects. Strikingly, expression of a cytoplasmic form of RTEL1 is sufficient to correct RNP mislocalizations both in RTEL1–HHS cells and in cells expressing nuclear mutated forms of RTEL1. This work unravels completely unanticipated roles for RTEL1 in RNP trafficking and strongly suggests that defects in RNP biogenesis pathways contribute to the pathology of HHS.
Detecting riboSNitches with RNA folding algorithms: a genome-wide benchmark
Authors: Corley Meredith , Solem Amanda , Qu Kun , Chang Howard Y. , Laederach Alain
Published: January 2015

Ribonucleic acid (RNA) secondary structure prediction continues to be a significant challenge, in particular when attempting to model sequences with less rigidly defined structures, such as messenger and non-coding RNAs. Crucial to interpreting RNA structures as they pertain to individual phenotypes is the ability to detect RNAs with large structural disparities caused by a single nucleotide variant (SNV) or riboSNitches. A recently published human genome-wide parallel analysis of RNA structure (PARS) study identified a large number of riboSNitches as well as non-riboSNitches, providing an unprecedented set of RNA sequences against which to benchmark structure prediction algorithms. Here we evaluate 11 different RNA folding algorithms’ riboSNitch prediction performance on these data. We find that recent algorithms designed specifically to predict the effects of SNVs on RNA structure, in particular remuRNA, RNAsnp and SNPfold, perform best on the most rigorously validated subsets of the benchmark data. In addition, our benchmark indicates that general structure prediction algorithms (e.g. RNAfold and RNAstructure) have overall better performance if base pairing probabilities are considered rather than minimum free energy calculations. Although overall aggregate algorithmic performance on the full set of riboSNitches is relatively low, significant improvement is possible if the highest confidence predictions are evaluated independently.