bluuebunny/crossref_metadata_2025 huggingface dataset:
Sorption of arsenate onto magnetic iron–manganese (Fe–Mn) biochar composites
Authors: Wang Shengsen , Gao Bin , Li Yuncong , Wan Yongshan , Creamer Anne Elise
Published: July 2015

Bimetal-biochar composites for arsenate (As(v)) removal.
Surfactant-free aqueous preparation from a star polymer of size-controlled nanoparticles with encapsulated functional molecules
Authors: Shibata Yuka , Santa Tomofumi , Kato Masaru
Published: July 2015

A simple preparation method for size-controlled nanoparticles with encapsulated functional molecules in a surfactant-free aqueous condition.
Ordered intermetallic PtFe@Pt core–shell nanoparticles supported on carbon nanotubes with superior activity and durability as oxygen reduction reaction electrocatalysts
Authors: Liu Haijing , Dou Meiling , Wang Feng , Liu Jingjun , Ji Jing , Li Zhilin
Published: July 2015

PtFe@Pt nanoparticles with ordered intermetallic cores and Pt shells were supported on CNTs and developed as an ORR electrocatalyst.
The mechanisms of flavonoids inhibiting conformational transition of amyloid-β42monomer: a comparative molecular dynamics simulation study
Authors: Wang Ling , Zeng Ranran , Pang Xiaoqian , Gu Qiong , Tan Wen
Published: July 2015

Flavonoids can bind Aβ42to inhibit the aggregation of Aβ42monomer.
Ultra-long SiC nanowires synthesized by a simple method
Authors: Hu Ping , Dong Shun , Gui Kaixuan , Deng Xianzhu , Zhang Xinghong
Published: July 2015

Ultra-long SiC nanowires synthesized by alumina-assisted growth of the vapor–solid (VS) mechanism.
Enhancement of thermoelectric efficiency of doped PCDTBT polymer films
Authors: Maiz Jon , Muñoz Rojo Miguel , Abad Begoña , Wilson Adam Andrew , Nogales Aurora , Borca-Tasciuc Diana-Andra , Borca-Tasciuc Theodorian , Martín-González Marisol
Published: July 2015

PCDTBT films doped with FeCl3 present a large power factor of 24 μW m−1 K−2 at 150 °C and a thermal conductivity of 1 W m−1 K−1 for the same film. This improvement is mainly achieved by up to 9 orders of magnitude increased in the electric conduction.
Microwave-assisted synthesis of pyrite FeS2 microspheres with strong absorption performance
Authors: Wu Jian , Liang Yuxuan , Bai Pengpeng , Zheng Shuqi , Chen Liqiang
Published: July 2015

Pyrite FeS2 microspheres with an average size of approximately 1.1 μm were successfully synthesised in high yield via a facile and efficient microwave-assisted method.
Correction: Magnetic g-C3N4/NiFe2O4 hybrids with enhanced photocatalytic activity
Authors: Ji Haiyan , Jing Xiaocui , Xu Yuanguo , Yan Jia , Li Hongping , Li Yeping , Huang Liying , Zhang Qi , Xu Hui , Li Huaming
Published: July 2015

Correction for ‘Magnetic g-C3N4/NiFe2O4 hybrids with enhanced photocatalytic activity’ by Haiyan Ji et al., RSC Adv., 2015, 5, 57960–57967.
Bridging cells of three colors with two bio-orthogonal click reactions
Authors: Yuan Yue , Li Di , Zhang Jia , Chen Xianmin , Zhang Chi , Ding Zhanling , Wang Lin , Zhang Xueqian , Yuan Junhua , Li Yinmei , Kang Yanbiao , Liang Gaolin
Published: July 2015

Two bio-orthogonal click reactions were employed to bridge prokaryotic E. coli or eukaryotic HEK 293T cells of three colors successfully.
Design rationale of thermally responsive microgel particle films that reversibly absorb large amounts of CO2: fine tuning the pKa of ammonium ions in the particles
Authors: Yue Mengchen , Hoshino Yu , Miura Yoshiko
Published: July 2015

Fine-tuning of pKa value of ammonium ions at both CO2 capture and release temperature is found to be crucial for the design of the thermally responsive gel particle films that reversibly capture large amounts of CO2.
Time scales for drainage and imbibition in gellified foams: application to decontamination processes
Authors: Deleurence Rémi , Saison Tamar , Lequeux François , Monteux Cécile
Published: July 2015

We probe the drainage and imbibition dynamics of foams in which the continuous aqueous phase is a transient polymer gel-like network. We find that these foams are unusually stable, as the drainage flow of the aqueous phase is extremely slow – several weeks. However they can quickly absorb liquids, in a few seconds. These foams could therefore be used to decontaminate surfaces.
Porous imine-based networks with protonated imine linkages for carbon dioxide separation from mixtures with nitrogen and methane
Authors: Popp Nadine , Homburg Thomas , Stock Norbert , Senker Jürgen
Published: July 2015

Porous imine-linked networks with protonated imine linkages and an ionic structure were synthesized. They exhibit good carbon dioxide uptakes and CO2/N2 as well as CO2/CH4 separation coefficients.
A single-step room-temperature electrochemical synthesis of nitrogen-doped graphene nanoribbons from carbon nanotubes
Authors: Jaison M. J. , Narayanan Tharangattu N. , Prem Kumar T. , Pillai Vijayamohanan K.
Published: July 2015

Multiwalled carbon nanotubes (MWCNTs) were transformed into nitrogen-doped graphene/graphitic nanoribbons (N-doped GNRs) in a single-step electrochemical process at room temperature in formamide, which acts as a solvent and a source of nitrogen.
Oxygen permeation and stability of Mo-substituted BSCF membranes
Authors: Gasparyan H. , Claridge J. B. , Rosseinsky M. J.
Published: July 2015

During 200 h of operation at 750 °C the performance of the Ba0.5Sr0.5Co0.8Fe0.2O3-δ membrane decays by 35%, while Ba0.5Sr0.5Co0.5Fe0.125Mo0.375O3-δ shows steady-state permeation and Ba0.5Sr0.5Co0.78Fe0.195Mo0.025O3-δ slows the decay by a factor of two.
Synthesis and characterization of (Ga1−xZnx)(N1−xOx) nanocrystals with a wide range of compositions
Authors: Lee Kyureon , Lu Ying-Gang , Chuang Chi-Hung , Ciston Jim , Dukovic Gordana
Published: July 2015

(Ga1−xZnx)(N1−xOx) nanocrystals with a wide range of compositions and band gaps are formed by topotactic nucleation at ZnO/ZnGa2O4 interfaces.
WSe2 and W(SexS1−x)2 nanoflakes grown on carbon nanofibers for the electrocatalytic hydrogen evolution reaction
Authors: Zou MeiLing , Chen JiaDong , Xiao LongFei , Zhu Han , Yang TingTing , Zhang Ming , Du MingLiang
Published: July 2015

Triangular W(SexS1−x)2 nanoflakes uniformly dispersed on the surface of electrospun carbon nanofiber mats were synthesized. The hybrid catalyst mats were directly used as hydrogen evolution cathodes and exhibit excellent HER performances.
A dual templating route to three-dimensionally ordered mesoporous carbon nanonetworks: tuning the mesopore type for electrochemical performance optimization
Authors: Wang Kaixi , Zhang Jianan , Xia Wei , Zou Ruqiang , Guo Junhui , Gao Zhongmin , Yan Wenfu , Guo Shaojun , Xu Qun
Published: July 2015

Ordered mesoporous carbon nanonetworks with a tunable mesopore type were synthesized by a dual-templating route for their electrochemical performance optimization.
Facile self-templating large scale preparation of biomass-derived 3D hierarchical porous carbon for advanced supercapacitors
Authors: Song Shijiao , Ma Fangwei , Wu Guang , Ma Di , Geng Weidan , Wan Jiafeng
Published: July 2015

Corn husk, a renewable biomass, has been successfully explored as a low-cost crude carbon source to prepare advanced higher-value 3D HPCs by means of KOH pre-treatment and direct pyrolysis, the synthesis route is simple, self-templating and easy to scale-up for industrialization.
Side chain modification: an effective approach to modulate the energy level of benzodithiophene based polymers for high-performance solar cells
Authors: Wu Haimei , Zhao Baofeng , Wang Weiping , Guo Zhaoqi , Wei Wei , An Zhongwei , Gao Chao , Chen Hui , Xiao Biao , Xie Yuan , Wu Hongbin , Cao Yong
Published: July 2015

Over the past few years, it has been proven that deepening the highest occupied molecular orbital (HOMO) levels of conjugated polymers is one of the most successful strategies to develop novel materials for high performance bulk heterojunction polymer solar cells.
Engineering 2D multi-layer graphene-like Co3O4 thin sheets with vertically aligned nanosheets as basic building units for advanced pseudocapacitor materials
Authors: Xuan Liying , Chen Lingyun , Yang Qingqing , Chen Weifan , Hou Xiaohuan , Jiang Yuqian , Zhang Qing , Yuan Yuan
Published: July 2015

Olivaceous 2D multi-layer graphene-like Co3O4 thin sheets (CQU-Chen-Co-O-1) with vertically aligned nanosheets as basic building units were first prepared and they exhibited excellent pseudocapacitive performance.
Light blue and green thermally activated delayed fluorescence from 10H-phenoxaborin-derivatives and their application to organic light-emitting diodes
Authors: Kitamoto Yuichi , Namikawa Taketo , Ikemizu Dai , Miyata Yasuo , Suzuki Takatsugu , Kita Hiroshi , Sato Tetsuo , Oi Shuichi
Published: July 2015

New luminescent compounds consisting of 10H-phenoxaboryl groups show excellent PLQYs and EQEs.
Recent progress in the applications of graphene in surface-enhanced Raman scattering and plasmon-induced catalytic reactions
Authors: Kang Leilei , Chu Jiayu , Zhao Hongtao , Xu Ping , Sun Mengtao
Published: July 2015

In this review, the advances in informative Raman spectra of graphene are firstly reviewed. Then, the graphene related SERS substrates are summarized. We finally highlight the catalytic reactions occurring on graphene itself and molecules adsorbed onto graphene upon laser irradiation.
Structural phase transitions coupled with prominent dielectric anomalies and dielectric relaxation in a one-dimensional organic–inorganic hybrid compound [C3H4NS][CdCl3]
Authors: Mei Guang-Quan , Liao Wei-Qiang
Published: July 2015

A one-dimensional organic–inorganic hybrid exhibits two phase transitions at 288 and 215 K, coupled with remarkable dielectric performances.
Role of miRNA-146 in proliferation and differentiation of mouse neural stem cells
Authors: Xiao Wei-Zhong , Lu An-Qing , Liu Xin-Wei , Li Zhe , Zi Ying , Wang Zhi-Wei
Published: July 2015

Neural stem cells (NSCs) have been defined as neural cells with the potential to self-renew and eventually generate all cell types of the nervous system. NSCs serve as an ideal cell type for nervous system repair. In the present study, miR-146 overexpression and predicted target (notch 1) were used to study proliferation and differentiation of mouse NSCs. shRNA were used to demonstrate the function of Notch 1 in proliferation of mouse NSCs and luciferase reporter assay was used to assess and confirm the binding sequence of 3′-UTR between Notch 1 and miR-146. Results showed that miR-146 overexpression and knockdown of notch 1 inhibited proliferation of mouse NSCs under serum-free cultural conditions and promoted spontaneous differentiation of mouse NSCs under contained serum cultural conditions respectively. Mouse NSCs spontaneously underwent differentiation into neurogenic cells with contained serum medium. However, when miR-146 was overexpressed, differentiation efficiency of glial cells from NSCs was increased, suggesting that Notch1 promoted NSC proliferation and repressed spontaneous differentiation of NSC in serum-free medium. In conclusion, our results demonstrate that miR-146 promoted spontaneous differentiation of NSCs, and this mechanism was influenced by miR-146, as well as its target (notch 1) and downstream gene.
Direct binding of hepatocyte growth factor and vascular endothelial growth factor to CD44v6
Authors: Volz Yvonne , Koschut David , Matzke-Ogi Alexandra , Dietz Marina S. , Karathanasis Christos , Richert Ludovic , Wagner Moritz G. , Mély Yves , Heilemann Mike , Niemann Hartmut H. , Orian-Rousseau Véronique
Published: July 2015

CD44v6, a member of the CD44 family of transmembrane glycoproteins is a co-receptor for two receptor tyrosine kinases (RTKs), Met and VEGFR-2 (vascular endothelial growth factor receptor 2). CD44v6 is not only required for the activation of these RTKs but also for signalling. In order to understand the role of CD44v6 in Met and VEGFR-2 activation and signalling we tested whether CD44v6 binds to their ligands, HGF (hepatocyte growth factor) and VEGF (vascular endothelial growth factor), respectively. FACS analysis and cellular ELISA showed binding of HGF and VEGF only to cells expressing CD44v6. Direct binding of CD44v6 to HGF and VEGF was demonstrated in pull-down assays and the binding affinities were determined using MicroScale Thermophoresis, fluorescence correlation spectroscopy and fluorescence anisotropy. The binding affinity of CD44v6 to HGF is in the micromolar range in contrast with the high-affinity binding measured in the case of VEGF and CD44v6, which is in the nanomolar range. These data reveal a heparan sulfate-independent direct binding of CD44v6 to the ligands of Met and VEGFR-2 and suggest different roles of CD44v6 for these RTKs.
Stress-mediated Sin3B activation leads to negative regulation of subset of p53 target genes
Authors: Kadamb Rama , Mittal Shilpi , Bansal Nidhi , Saluja Daman
Published: July 2015

The multiprotein SWI-independent 3 (Sin3)–HDAC (histone deacetylase) corepressor complex mediates gene repression through its interaction with DNA-binding factors and recruitment of chromatin-modifying proteins on to the promoters of target gene. Previously, an increased expression of Sin3B and tumour suppressor protein, p53 has been established upon adriamycin treatment. We, now provide evidence that Sin3B expression is significantly up-regulated under variety of stress conditions and this response is not stress-type specific. We observed that Sin3B expression is significantly up-regulated both at transcript and at protein level upon DNA damage induced by bleomycin drug, a radiomimetic agent. This increase in Sin3B expression upon stress is found to be p53-dependent and is associated with enhanced interaction of Sin3B with Ser15 phosphorylated p53. Binding of Sin3–HDAC repressor complex on to the promoters of p53 target genes influences gene regulation by altering histone modifications (H3K9me3 and H3K27me3) at target genes. Furthermore, knockdown of Sin3B by shRNA severely compromises p53-mediated gene repression under stress conditions. Taken together, these results suggest that stress-induced Sin3B activation is p53-dependent and is essential for p53-mediated repression of its selective target genes. The present study has an implication in understanding the transrepression mechanism of p53 under DNA damaging conditions.
Adenylylsulfate–ammonia adenylyltransferase activity is another inherent property of Fhit proteins
Authors: Wojdyła-Mamoń Anna M. , Guranowski Andrzej
Published: July 2015

Fhits (fragile histidine triad proteins) occur in eukaryotes but their function is largely unknown, although human Fhit is believed to act as a tumour suppressor. Fhits also exhibit dinucleoside triphosphatase, adenylylsulfatase and nucleoside phosphoramidase activities that in each case yield nucleoside 5′-monophosphate as a product. Due to the dinucleoside triphosphatase activity, Fhits may also be involved in mRNA decapping. In the present study, we demonstrate Fhit-catalysed ammonolysis of adenosine 5′-phosphosulfate, which results in the formation of adenosine 5′-phosphoramidate. This reaction has previously been associated with adenylylsulfate–ammonia adenylyltransferase (EC 2.7.7.51). Our finding shows that the capacity to catalyse ammonolysis is another inherent property of Fhits. Basic kinetic parameters and substrate specificity of this reaction catalysed by human Fhit are presented.
Decreased Bioenergetic Health Index in monocytes isolated from the pericardial fluid and blood of post-operative cardiac surgery patients
Authors: Kramer Philip A. , Chacko Balu K. , George David J. , Zhi Degui , Wei Chih-Cheng , Dell'Italia Louis J. , Melby Spencer J. , George James F. , Darley-Usmar Victor M.
Published: July 2015

Monitoring the bioenergetics of leucocytes is now emerging as an important approach in translational research to detect mitochondrial dysfunction in blood or other patient samples. Using the mitochondrial stress test, which involves the sequential addition of mitochondrial inhibitors to adherent leucocytes, we have calculated a single value, the Bioenergetic Health Index (BHI), which represents the mitochondrial function in cells isolated from patients. In the present report, we assess the BHI of monocytes isolated from the post-operative blood and post-operative pericardial fluid (PO-PCF) from patients undergoing cardiac surgery. Analysis of the bioenergetics of monocytes isolated from patients’ PO-PCF revealed a profound decrease in mitochondrial function compared with monocytes isolated from their blood or from healthy controls. Further, patient blood monocytes showed no significant difference in the individual energetic parameters from the mitochondrial stress test but, when integrated into the BHI evaluation, there was a significant decrease in BHI compared with healthy control monocytes. These data support the utility of BHI measurements in integrating the individual parameters from the mitochondrial stress test into a single value. Supporting our previous finding that the PO-PCF is pro-oxidant, we found that exposure of rat cardiomyocytes to PO-PCF caused a significant loss of mitochondrial membrane potential and increased reactive oxygen species (ROS). These findings support the hypothesis that integrated measures of bioenergetic health could have prognostic and diagnostic value in translational bioenergetics.
Energy efficient relay selection and power allocation for cooperative cognitive radio networks
Authors: Chen Jian , Lv Lu , Liu Yiyang , Kuo Yonghong , Ren Chao
Published: July 2015

Owing to environmental, financial and quality of service (QoS) considerations, energy efficient wireless communications have been paid increasing attention under the background of limited energy resource. This study considers a spectrum sharing cognitive radio network, where the primary system leases its radio spectrum to the secondary system for a fraction of time in exchange for secondary users served as relays to assist the transmission of the primary traffic. Based on the cooperative spectrum leasing protocol, the authors formulate a joint optimisation of relay selection and power allocation under QoS requirements to improve energy efficiency (EE). By employing a greedy spectrum sharing (GSS) algorithm, the optimal relay selection, power and sharing time allocation are readily obtained. Monte–Carlo simulations are performed to demonstrate that significant EE improvement is achieved by the proposed GSS algorithm, and that the network performance is enhanced.
Selective cooperative decoding based on a hard‐decision‐aided log‐likelihood ratio approximation
Authors: Le Duong Long , Baek Jong‐Hyen , Lee Kyungchun
Published: July 2015

This study presents novel strategies to improve the decoding performance through base‐station cooperation. In the proposed schemes, the soft output of the demapper at a serving base station (SBS) is replaced by a combination of log‐likelihood ratio information, which is generated through demodulation by neighbouring base stations (NBSs) as well as the SBS. For the information used in the cooperation, soft information is first considered. Combining the soft information transmitted from all NBSs provides close‐to‐optimal performance, but it still requires a high amount of overhead to be passed over the backhaul links. In the proposed schemes, the SBS only cooperates with the reliable NBSs, which are identified on the basis of the magnitude of the metrics transmitted from the NBSs, to achieve a trade‐off between performance and overhead. In addition, the use of hard information instead of soft information is also proposed to further reduce the backhaul overhead. In this scheme, the metric values as well as the hard information are exploited to generate the updated soft information for the channel decoder. In the simulation results, it is shown that the proposed schemes provide better error performance compared with the conventional schemes under limited backhaul capacities.
Fuel consumption in empirical synchronised flow in urban traffic
Authors: Hemmerle Peter , Koller Micha , Rehborn Hubert , Kerner Boris S. , Schreckenberg Michael
Published: July 2015

Based on an empirical study of real field global positioning system data obtained from navigation devices in vehicles, the authors analyse fuel consumption of vehicles in city traffic. They show that synchronised flow patterns, revealed recently in real field oversaturated city traffic, exhibit considerable impact on fuel consumption. In particular, they have found out that fuel consumption in oversaturated city traffic can decrease considerably when oversaturated city traffic consists of synchronised flow patterns rather than consisting of moving queues of the classical traffic flow theory at traffic signals. Using empirical data from two different road sections in the city of Düsseldorf, Germany, the authors show that synchronised flow patterns and moving queues differ in their cumulated vehicle acceleration (a sum of positive speed differences along a vehicle trajectory) despite similar mean vehicle speeds. Fuel consumption in return is dependent on the cumulated vehicle acceleration. This latter dependency is obtained by means of a macroscopic consumption matrix based on empirical field trial consumption data and simulated speed and acceleration profiles. The authors sketch out the application of the study results to route guidance by demonstrating that the most energy‐efficient route in a road network can differ from the fastest route.
Revisited reaction-diffusion model of thermal desorption spectroscopy experiments on hydrogen retention in material
Authors: Guterl Jerome , Smirnov R. D. , Krasheninnikov S. I.
Published: July 2015

Desorption phase of thermal desorption spectroscopy (TDS) experiments performed on tungsten samples exposed to flux of hydrogen isotopes in fusion relevant conditions is analyzed using a reaction-diffusion model describing hydrogen retention in material bulk. Two regimes of hydrogen desorption are identified depending on whether hydrogen trapping rate is faster than hydrogen diffusion rate in material during TDS experiments. In both regimes, a majority of hydrogen released from material defects is immediately outgassed instead of diffusing deeply in material bulk when the evolution of hydrogen concentration in material is quasi-static, which is the case during TDS experiments performed with tungsten samples exposed to flux of hydrogen isotopes in fusion related conditions. In this context, analytical expressions of the hydrogen outgassing flux as a function of the material temperature are obtained with sufficient accuracy to describe main features of thermal desorption spectra (TDSP). These expressions are then used to highlight how characteristic temperatures of TDSP depend on hydrogen retention parameters, such as trap concentration or activation energy of detrapping processes. The use of Arrhenius plots to characterize retention processes is then revisited when hydrogen trapping takes place during TDS experiments. Retention processes are also characterized using the shape of desorption peaks in TDSP, and it is shown that diffusion of hydrogen in material during TDS experiment can induce long desorption tails visible aside desorption peaks at high temperature in TDSP. These desorption tails can be used to estimate activation energy of diffusion of hydrogen in material.
Separation of DNA by length in rotational flow: Lattice-Boltzmann-based simulations
Authors: Alfahani Faihan , Antonelli Michael , Kreft Pearce Jennifer
Published: July 2015

We use a lattice-Boltzmann based Brownian dynamics simulation to investigate the separation of different lengths of DNA through the combination of a trapping force and the microflow created by counter-rotating vortices. We can separate most long DNA molecules from shorter chains that have lengths differing by as little as 30%. The sensitivity of this technique is determined by the flow rate, size of the trapping region, and the trapping strength. We expect that this technique can be used in microfluidic devices to separate long DNA fragments that result from techniques such as restriction enzyme digests of genomic DNA.
Graphene oxide as an optimal candidate material for methane storage
Authors: Chouhan Rajiv K. , Ulman Kanchan , Narasimhan Shobhana
Published: July 2015

Methane, the primary constituent of natural gas, binds too weakly to nanostructured carbons to meet the targets set for on-board vehicular storage to be viable. We show, using density functional theory calculations, that replacing graphene by graphene oxide increases the adsorption energy of methane by 50%. This enhancement is sufficient to achieve the optimal binding strength. In order to gain insight into the sources of this increased binding, that could also be used to formulate design principles for novel storage materials, we consider a sequence of model systems that progressively take us from graphene to graphene oxide. A careful analysis of the various contributions to the weak binding between the methane molecule and the graphene oxide shows that the enhancement has important contributions from London dispersion interactions as well as electrostatic interactions such as Debye interactions, aided by geometric curvature induced primarily by the presence of epoxy groups.
Desktop aligner for fabrication of multilayer microfluidic devices
Authors: Li Xiang , Yu Zeta Tak For , Geraldo Dalton , Weng Shinuo , Alve Nitesh , Dun Wu , Kini Akshay , Patel Karan , Shu Roberto , Zhang Feng , Li Gang , Jin Qinghui , Fu Jianping
Published: July 2015

Multilayer assembly is a commonly used technique to construct multilayer polydimethylsiloxane (PDMS)-based microfluidic devices with complex 3D architecture and connectivity for large-scale microfluidic integration. Accurate alignment of structure features on different PDMS layers before their permanent bonding is critical in determining the yield and quality of assembled multilayer microfluidic devices. Herein, we report a custom-built desktop aligner capable of both local and global alignments of PDMS layers covering a broad size range. Two digital microscopes were incorporated into the aligner design to allow accurate global alignment of PDMS structures up to 4 in. in diameter. Both local and global alignment accuracies of the desktop aligner were determined to be about 20 μm cm−1. To demonstrate its utility for fabrication of integrated multilayer PDMS microfluidic devices, we applied the desktop aligner to achieve accurate alignment of different functional PDMS layers in multilayer microfluidics including an organs-on-chips device as well as a microfluidic device integrated with vertical passages connecting channels located in different PDMS layers. Owing to its convenient operation, high accuracy, low cost, light weight, and portability, the desktop aligner is useful for microfluidic researchers to achieve rapid and accurate alignment for generating multilayer PDMS microfluidic devices.
Analysis of the correlation dimension for inertial particles
Authors: Gustavsson Kristian , Mehlig Bernhard , Wilkinson Michael
Published: July 2015

We obtain an implicit equation for the correlation dimension which describes clustering of inertial particles in a complex flow onto a fractal measure. Our general equation involves a propagator of a nonlinear stochastic process in which the velocity gradient of the fluid appears as additive noise. When the long-time limit of the propagator is considered our equation reduces to an existing large-deviation formalism from which it is difficult to extract concrete results. In the short-time limit, however, our equation reduces to a solvability condition on a partial differential equation. In the case where the inertial particles are much denser than the fluid, we show how this approach leads to a perturbative expansion of the correlation dimension, for which the coefficients can be obtained exactly and in principle to any order. We derive the perturbation series for the correlation dimension of inertial particles suspended in three-dimensional spatially smooth random flows with white-noise time correlations, obtaining the first 33 non-zero coefficients exactly.
Analytical gradients of the state-average complete active space self-consistent field method with density fitting
Authors: Delcey Mickaël G. , Pedersen Thomas Bondo , Aquilante Francesco , Lindh Roland
Published: July 2015

An efficient implementation of the state-averaged complete active space self-consistent field (SA-CASSCF) gradients employing density fitting (DF) is presented. The DF allows a reduction both in scaling and prefactors of the different steps involved. The performance of the algorithm is demonstrated on a set of molecules ranging up to an iron-Heme b complex which with its 79 atoms and 811 basis functions is to our knowledge the largest SA-CASSCF gradient computed. For smaller systems where the conventional code could still be used as a reference, both the linear response calculation and the gradient formation showed a clear timing reduction and the overall cost of a geometry optimization is typically reduced by more than one order of magnitude while the accuracy loss is negligible.
Time-dependent q-deformed bi-coherent states for generalized uncertainty relations
Authors: Gouba Laure
Published: July 2015

We consider the time-dependent bi-coherent states that are essentially the Gazeau-Klauder coherent states for the two dimensional noncommutative harmonic oscillator. Starting from some q-deformations of the oscillator algebra for which the entire deformed Fock space can be constructed explicitly, we define the q-deformed bi-coherent states. We verify the generalized Heisenberg’s uncertainty relations projected onto these states. For the initial value in time, the states are shown to satisfy a generalized version of Heisenberg’s uncertainty relations. For the initial value in time and for the parameter of noncommutativity θ = 0, the inequalities are saturated for the simultaneous measurement of the position-momentum observables. When the time evolves, the uncertainty products are different from their values at the initial time and do not always respect the generalized uncertainty relations.
Thermal-history dependent magnetoelastic transition in (Mn,Fe)2(P,Si)
Authors: Miao X. F. , Caron L. , Gercsi Z. , Daoud-Aladine A. , van Dijk N. H. , Brück E.
Published: July 2015

The thermal-history dependence of the magnetoelastic transition in (Mn,Fe)2(P,Si) compounds has been investigated using high-resolution neutron diffraction. As-prepared samples display a large difference in paramagnetic-ferromagnetic (PM-FM) transition temperature compared to cycled samples. The initial metastable state transforms into a lower-energy stable state when the as-prepared sample crosses the PM-FM transition for the first time. This additional transformation is irreversible around the transition temperature and increases the energy barrier which needs to be overcome through the PM-FM transition. Consequently, the transition temperature on first cooling is found to be lower than on subsequent cycles characterizing the so-called “virgin effect.” High-temperature annealing can restore the cycled sample to the high-temperature metastable state, which leads to the recovery of the virgin effect. A model is proposed to interpret the formation and recovery of the virgin effect.
Waveguide-coupled detector in zero-change complementary metal–oxide–semiconductor
Authors: Alloatti L. , Srinivasan S. A. , Orcutt J. S. , Ram R. J.
Published: July 2015

We report a waveguide-coupled photodetector realized in a standard CMOS foundry without requiring changes to the process flow (zero-change CMOS). The photodetector exploits carrier generation in the silicon-germanium normally utilized as stressor in pFETs. The measured responsivity and 3 dB bandwidth are of 0.023 A/W at a wavelength of 1180 nm and 32 GHz at −1 V bias (18 GHz at 0 V bias). The dark current is less than 10 pA and the dynamic range is larger than 60 dB.
Phases, phase equilibria, and phase rules in low-dimensional systems
Authors: Frolov T. , Mishin Y.
Published: July 2015

We present a unified approach to thermodynamic description of one, two, and three dimensional phases and phase transformations among them. The approach is based on a rigorous definition of a phase applicable to thermodynamic systems of any dimensionality. Within this approach, the same thermodynamic formalism can be applied for the description of phase transformations in bulk systems, interfaces, and line defects separating interface phases. For both lines and interfaces, we rigorously derive an adsorption equation, the phase coexistence equations, and other thermodynamic relations expressed in terms of generalized line and interface excess quantities. As a generalization of the Gibbs phase rule for bulk phases, we derive phase rules for lines and interfaces and predict the maximum number of phases than may coexist in systems of the respective dimensionality.
Single-photon emission at a rate of 143 MHz from a deterministic quantum-dot microlens triggered by a mode-locked vertical-external-cavity surface-emitting laser
Authors: Schlehahn A. , Gaafar M. , Vaupel M. , Gschrey M. , Schnauber P. , Schulze J.-H. , Rodt S. , Strittmatter A. , Stolz W. , Rahimi-Iman A. , Heindel T. , Koch M. , Reitzenstein S.
Published: July 2015

We report on the realization of a quantum dot (QD) based single-photon source with a record-high single-photon emission rate. The quantum light source consists of an InGaAs QD which is deterministically integrated within a monolithic microlens with a distributed Bragg reflector as back-side mirror, which is triggered using the frequency-doubled emission of a mode-locked vertical-external-cavity surface-emitting laser (ML-VECSEL). The utilized compact and stable laser system allows us to excite the single-QD microlens at a wavelength of 508 nm with a pulse repetition rate close to 500 MHz at a pulse width of 4.2 ps. Probing the photon statistics of the emission from a single QD state at saturation, we demonstrate single-photon emission of the QD-microlens chip with g(2)(0) < 0.03 at a record-high single-photon flux of (143 ± 16) MHz collected by the first lens of the detection system. Our approach is fully compatible with resonant excitation schemes using wavelength tunable ML-VECSELs, which will optimize the quantum optical properties of the single-photon emission in terms of photon indistinguishability.
Finite-time braiding exponents
Authors: Budišić Marko , Thiffeault Jean-Luc
Published: July 2015

Topological entropy of a dynamical system is an upper bound for the sum of positive Lyapunov exponents; in practice, it is strongly indicative of the presence of mixing in a subset of the domain. Topological entropy can be computed by partition methods, by estimating the maximal growth rate of material lines or other material elements, or by counting the unstable periodic orbits of the flow. All these methods require detailed knowledge of the velocity field that is not always available, for example, when ocean flows are measured using a small number of floating sensors. We propose an alternative calculation, applicable to two-dimensional flows, that uses only a sparse set of flow trajectories as its input. To represent the sparse set of trajectories, we use braids, algebraic objects that record how trajectories exchange positions with respect to a projection axis. Material curves advected by the flow are represented as simplified loop coordinates. The exponential rate at which a braid stretches loops over a finite time interval is the Finite-Time Braiding Exponent (FTBE). We study FTBEs through numerical simulations of the Aref Blinking Vortex flow, as a representative of a general class of flows having a single invariant component with positive topological entropy. The FTBEs approach the value of the topological entropy from below as the length and number of trajectories is increased; we conjecture that this result holds for a general class of ergodic, mixing systems. Furthermore, FTBEs are computed robustly with respect to the numerical time step, details of braid representation, and choice of initial conditions. We find that, in the class of systems we describe, trajectories can be re-used to form different braids, which greatly reduces the amount of data needed to assess the complexity of the flow.
Landau damping of Gardner solitons in a dusty bi-ion plasma
Authors: Misra A. P. , Barman Arnab
Published: July 2015

The effects of linear Landau damping on the nonlinear propagation of dust-acoustic solitary waves (DASWs) are studied in a collisionless unmagnetized dusty plasma with two species of positive ions. The extremely massive, micron-seized, cold, and negatively charged dust particles are described by fluid equations, whereas the two species of positive ions, namely, the cold (heavy) and hot (light) ions are described by the kinetic Vlasov equations. Following Ott and Sudan [Phys. Fluids 12, 2388 (1969)], and by considering lower and higher-order perturbations, the evolution of DASWs with Landau damping is shown to be governed by Korteweg-de Vries (KdV), modified KdV (mKdV), or Gardner (KdV-mKdV)-like equations. The properties of the phase velocity and the Landau damping rate of DASWs are studied for different values of the ratios of the temperatures (σ) and the number densities (μ) of hot and cold ions as well as the cold to hot ion mass ratio m. The distinctive features of the decay rates of the amplitudes of the KdV, mKdV, and Gardner solitons with a small effect of Landau damping are also studied in different parameter regimes. It is found that the Gardner soliton points to lower wave amplitudes than the KdV and mKdV solitons. The results may be useful for understanding the localization of solitary pulses and associated wave damping (collisionless) in laboratory and space plasmas (e.g., the F-ring of Saturn), in which the number density of free electrons is much smaller than that of ions and the heavy, micron seized dust grains are highly charged.
Communication: UV photoionization of cytosine catalyzed by Ag+
Authors: Taccone Martín I. , Féraud Geraldine , Berdakin Matías , Dedonder-Lardeux Claude , Jouvet Christophe , Pino Gustavo A.
Published: July 2015

The photo-induced damages of DNA in interaction with metal cations, which are found in various environments, still remain to be characterized. In this paper, we show how the complexation of a DNA base (cytosine (Cyt)) with a metal cation (Ag+) changes its electronic properties. By means of UV photofragment spectroscopy of cold ions, it was found that the photoexcitation of the CytAg+ complex at low energy (315-282) nm efficiently leads to ionized cytosine (Cyt+) as the single product. This occurs through a charge transfer state in which an electron from the p orbital of Cyt is promoted to Ag+, as confirmed by ab initio calculations at the TD-DFT/B3LYP and RI-ADC(2) theory level using the SV(P) basis set. The low ionization energy of Cyt in the presence of Ag+ could have important implications as point mutation of DNA upon sunlight exposition.
Switching microwaves via semiconductor-isolator reversible transition in a thin-film of MoS2
Authors: Dragoman Mircea , Cismaru Alina , Aldrigo Martino , Radoi Antonio , Dragoman Daniela
Published: July 2015

In this paper, we show that a thin-film of MoS2 is able to switch microwave signals due to a reversible semiconductor-insulator transition displaying an ON/OFF ratio greater than 104. This switching occurs in the range of 4–16 GHz, which encompasses the C, X, and K bands. In this respect, the current-voltage dependence and the microwave properties of the MoS2 thin-film are investigated. An integrated microwave switch device and a single pole double throw switch circuit are then implemented based on this unique property.
Determination of g-tensors of low-symmetry Nd3+ centers in LiNbO3 by rectification of angular dependence of electron paramagnetic resonance spectra
Authors: Grachev V. , Munro M. , Kokanyan E. , Malovichko G.
Published: July 2015

Two procedures for facilitation of line tracing and deciphering of complicated spectra of electron paramagnetic resonance (EPR) were developed: a correction of microwave frequencies for every orientation of external magnetic field on the base of known values of g-tensor components for a reference paramagnetic center and followed rectification of measured angular dependences using plots of effective deviation of g2-factors of observed lines from effective g2-factors of the reference center versus angles or squared cosines of angles describing magnetic field orientations. Their application to EPR spectra of nearly stoichiometric lithium niobate crystals doped with neodymium allowed identifying two axial and six different low-symmetry Nd3+ centers, to determine all components of their g-tensors, and to propose common divacancy models for a whole family of Nd3+ centers.
An ab-initio density functional theory investigation of fullerene/Zn-phthalocyanine (C60/ZnPc) interface with face-on orientation
Authors: Javaid Saqib , Javed Akhtar M.
Published: July 2015

We have employed density functional theory to study the C60/ZnPc interface with face-on orientation, which has recently been tailored experimentally. For this purpose, adsorption of ZnPc on C60 has been studied, while taking into account different orientations of C60. Out of various adsorption sites investigated, 6:6 C-C bridge position in apex configuration of C60 has been found energetically the most favourable one with C60-ZnPc adsorption distance of ∼2.77 Å. The adsorption of ZnPc on C60 ensues both charge re-organization and charge transfer at the interface, resulting in the formation of interface dipole. Moreover, by comparing results with that of C60/CuPc interface, we show that the direction of interface dipole can be tuned by the change of the central atom of the phthalocyanine molecule. These results highlight the complexity of electronic interactions present at the C60/Phthalocyanine interface.
Defect-dependent carrier transport behavior of polymer:ZnO composites/electrodeposited CdS/indium tin oxide devices
Authors: Lin Yow-Jon , You C. F.
Published: July 2015

Currents through the poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) and ZnO nanoparticles (PEDOT:PSS:ZnO)/CdS/indium tin oxide (ITO) hetero-structures are studied. The authors introduced the electrodeposition technique with sulfide treatment to improve the film quality of CdS. It is shown that sulfide treatment leads to a reduction in the number of donor-like defects (that is, sulfur vacancies and cadmium interstitials) in the CdS films, which leads to the conversion of carrier transport behavior from Poole-Frenkel emission to thermionic emission-diffusion for PEDOT:PSS:ZnO/CdS/ITO devices. A correlation is identified for providing a guide to control the current transport behavior of PEDOT:PSS:ZnO/CdS/ITO devices.
Note: Improved technique for ultrashort lasers pulse width stabilization
Authors: Shelestov Dmitriy , Lazarev Vladimir , Karasik Valeriy , Koshelev Kirill , Pnev Alexey , Grudinin Anatoly
Published: July 2015

We have developed an improved pulse width stabilization method based on the second harmonic generation (SHG) technique using the relationship between pulse width, input intensity, and SHG intensity. On the basis of an analysis of the improved method accuracy, we then proposed a novel processing algorithm, which allowed us to increase the accuracy of pulse width stabilization to 1.2%. We applied this method to a picosecond Yb-doped fiber laser, which offers pulse widths ranging from 10 to 14 ps. We have demonstrated, for what is believed to be the first time, pulse width stabilization of this laser with an absolute error of less than 200 fs.
Fluorene- and benzofluorene-cored oligomers as low threshold and high gain amplifying media
Authors: Kazlauskas Karolis , Kreiza Gediminas , Bobrovas Olegas , Adomėnienė Ona , Adomėnas Povilas , Jankauskas Vygintas , Juršėnas Saulius
Published: July 2015

Deliberate control of intermolecular interactions in fluorene- and benzofluorene-cored oligomers was attempted via introduction of different-length alkyl moieties to attain high emission amplification and low amplified spontaneous emission (ASE) threshold at high oligomer concentrations. Containing fluorenyl peripheral groups decorated with different-length alkyl moieties, the oligomers were found to express weak concentration quenching of emission, yet excellent carrier drift mobilities (close to 10−2 cm2/V/s) in the amorphous films. Owing to the larger radiative decay rates (>1.0 × 109 s−1) and smaller concentration quenching, fluorene-cored oligomers exhibited down to one order of magnitude lower ASE thresholds at higher concentrations as compared to those of benzofluorene counterparts. The lowest threshold (300 W/cm2) obtained for the fluorene-cored oligomers at the concentration of 50 wt % in polymer matrix is among the lowest reported for solution-processed amorphous films in ambient conditions, what makes the oligomers promising for lasing application. Great potential in emission amplification was confirmed by high maximum net gain (77 cm−1) revealed for these compounds. Although the photostability of the oligomers was affected by photo-oxidation, it was found to be comparable to that of various organic lasing materials including some commercial laser dyes evaluated under similar excitation conditions.
Direct observation of closure domain wall mediated spin waves
Authors: Mozooni Babak , McCord Jeffrey
Published: July 2015

The generation and guiding of spin waves from and by magnetic domain walls are demonstrated. The spin waves radiate from pinned and oscillating magnetic closure domain walls and propagate linearly along a narrow path formed by the surrounding 180° asymmetric Bloch domain walls. The propagating spin wave modes are directly visualized by time-resolved magneto-optical Kerr microscopy with picosecond temporal resolution. A linear relationship between excitation frequency, wavelength, and number of spin waves per domain exists. Independent of the field excitation frequency, a constant phase velocity of spin waves propagation is obtained. Spin waves characteristics can be tuned by varying the magnetic domain dynamics, allowing for variable spin wave characteristics with magnetic field characteristics and histories.
Insight on the ferroelectric properties in a (BiFeO3)2(SrTiO3)4 superlattice from experiment and ab initio calculations
Authors: Bruyer E. , Sayede A. , Ferri A. , Desfeux R. , Mangalam R. V. K. , Ranjith R. , Prellier W.
Published: July 2015

Ferroelectric domain properties of a (BiFeO3)2(SrTiO3)4 superlattice were studied by means of piezoresponse force microscopy and density functional theory calculations. A combination of out-of-plane and in-plane piezoresponse force imaging confirms that the ferroelectric domains are oriented along the out-of-plane [001] direction of the film. Density functional theory calculations evidence that this orientation is due to the tetragonal-like structure adopted by the BiFeO3 units inside the superlattice in response to the interfacial strains. In addition, antiferrodistortive rotations of the BO2 planes within both types of ABO3 blocks (i.e., SrTiO3 as well as BiFeO3 units) are highlighted. Besides, a much lower coercive voltage is measured on superlattices compared to BiFeO3 single layers, suggesting a more reliable switching capability. The results are expected to enable the design of promising multifunctional oxide superlattices.