bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic subnuclear relocalisation of WRKY40 in response to Abscisic acid in Arabidopsis thaliana
Authors: Geilen Katja , Böhmer Maik
Published: August 2015

WRKY18, WRKY40 and WRKY60 are members of the WRKY transcription factor family and function as transcriptional regulators in ABA signal transduction in Arabidopsis thaliana. Here we show that WRKY18 and WRKY40, but not WRKY60, co-localise with PIF3, PIF4 and PHYB to Phytochrome B-containing nuclear bodies (PNBs). Localisation to the PNBs is phosphorylation-dependent and is inhibited by the general Ser/Thr-kinase inhibitor Staurosporine. Upon ABA treatment, WRKY40 relocalises from PNBs to the nucleoplasm in an OST1-dependent manner. This stimulus-induced relocalisation was not observed in response to other abiotic or biotic stimuli, including NaCl, MeJA or flg22 treatment. Bimolecular fluorescence complementation experiments indicate that while PIF3, PIF4 and PHYB physically interact in these bodies, PHYB, PIF3 and PIF4 do not interact with the two WRKY transcription factors, which may suggest a more general role for these bodies in regulation of transcriptional activity.
Exometabolom analysis of breast cancer cell lines: Metabolic signature
Authors: Willmann Lucas , Erbes Thalia , Halbach Sebastian , Brummer Tilman , Jäger Markus , Hirschfeld Marc , Fehm Tanja , Neubauer Hans , Stickeler Elmar , Kammerer Bernd
Published: August 2015

Cancer cells show characteristic effects on cellular turnover and DNA/RNA modifications leading to elevated levels of excreted modified nucleosides. We investigated the molecular signature of different subtypes of breast cancer cell lines and the breast epithelial cell line MCF-10A. Prepurification of cell culture supernatants was performed by cis-diol specific affinity chromatography using boronate-derivatized polyacrylamide gel. Samples were analyzed by application of reversed phase chromatography coupled to a triple quadrupole mass spectrometer. Collectively, we determined 23 compounds from RNA metabolism, two from purine metabolism, five from polyamine/methionine cycle, one from histidine metabolism and two from nicotinate and nicotinamide metabolism. We observed major differences of metabolite excretion pattern between the breast cancer cell lines and MCF-10A, just as well as between the different breast cancer cell lines themselves. Differences in metabolite excretion resulting from cancerous metabolism can be integrated into altered processes on the cellular level. Modified nucleosides have great potential as biomarkers in due consideration of the heterogeneity of breast cancer that is reflected by the different molecular subtypes of breast cancer. Our data suggests that the metabolic signature of breast cancer cell lines might be a more subtype-specific tool to predict breast cancer, rather than a universal approach.
Transcriptomic analysis of pancreatic cancer cells in response to metformin and aspirin: an implication of synergy
Authors: Yue Wen , Wang Tao , Zachariah Emmanuel , Lin Yong , Yang Chung S. , Xu Qing , DiPaola Robert S. , Tan Xiang-Lin
Published: August 2015

Metformin and aspirin have been studied extensively as cancer preventative and therapeutic agents. However, the underlying molecular mechanisms for the inhibitory effects of pancreatic cancer development remain undefined. To gain further insight into their biological function in pancreatic cancer, we conducted a transcriptomic analysis using RNA sequencing to assess the differential gene expression induced by metformin (5 mM) and aspirin (2 mM), alone or in combination, after treatment of PANC-1 cells for 48 hours. Compared to an untreated control, metformin down-regulated 58 genes and up-regulated 91 genes, aspirin down-regulated 12 genes only, while metformin plus aspirin down-regulated 656 genes and up-regulated 449 genes (fold-change > 2, P < 10−5). Of the top 10 genes (fold-change > 10, P < 10−10) regulated by metformin plus aspirin, PCDH18, CCL2, RASL11A, FAM111B and BMP5 were down-regulated ≥ 20-fold, while NGFR, NPTX1, C7orf57, MRPL23AS1 and UNC5B were up-regulated ≥ 10-fold. Ingenuity Pathway Analysis (IPA) revealed that the pathways, “cholesterol biosynthesis”, “cell cycle: G1/S checkpoint regulation” and “axonal guidance signaling” were the most statistically significant pathways modulated by metformin plus aspirin. Although the results need further functional validation, these data provide the first evidence for the synergistic action between metformin and aspirin in modulating the transcriptional profile of pancreatic cancer cells.
Real-time analysis of epithelial-mesenchymal transition using fluorescent single-domain antibodies
Authors: Maier Julia , Traenkle Bjoern , Rothbauer Ulrich
Published: August 2015

Vimentin has become an important biomarker for epithelial-mesenchymal transition (EMT), a highly dynamic cellular process involved in the initiation of metastasis and cancer progression. To date there is no approach available to study endogenous vimentin in a physiological context. Here, we describe the selection and targeted modification of novel single-domain antibodies, so-called nanobodies, to trace vimentin in various cellular assays. Most importantly, we generated vimentin chromobodies by combining the binding moieties of the nanobodies with fluorescent proteins. Following chromobody fluorescence in a cancer-relevant cellular model, we were able for the first time to monitor and quantify dynamic changes of endogenous vimentin upon siRNA-mediated knockdown, induction with TGF-β and modification with Withaferin A by high-content imaging. This versatile approach allows detailed studies of the spatiotemporal organization of vimentin in living cells. It enables the identification of vimentin-modulating compounds, thereby providing the basis to screen for novel therapeutics affecting EMT.
Sonorensin: A new bacteriocin with potential of an anti-biofilm agent and a food biopreservative
Authors: Chopra Lipsy , Singh Gurdeep , Kumar Jena Kautilya , Sahoo Debendra K.
Published: August 2015

The emergence of antibiotic resistant bacteria has led to exploration of alternative therapeutic agents such as ribosomally synthesized bacterial peptides known as bacteriocins. Biofilms, which are microbial communities that cause serious chronic infections, form environments that enhance antimicrobial resistance. Bacteria in biofilm can be upto thousand times more resistant to antibiotics than the same bacteria circulating in a planktonic state. In this study, sonorensin, predicted to belong to the heterocycloanthracin subfamily of bacteriocins, was found to be effectively killing active and non-multiplying cells of both Gram-positive and Gram-negative bacteria. Sonorensin showed marked inhibition activity against biofilm of Staphylococcus aureus. Fluorescence and electron microscopy suggested that growth inhibition occurred because of increased membrane permeability. Low density polyethylene film coated with sonorensin was found to effectively control the growth of food spoilage bacteria like Listeria monocytogenes and S. aureus. The biopreservative effect of sonorensin coated film showing growth inhibition of spoilage bacteria in chicken meat and tomato samples demonstrated the potential of sonorensin as an alternative to current antibiotics/ preservatives.
Chromatographic ECD fingerprints combined with a chemometric method used for the identification of three light-coloured unifloral honeys
Authors: Zhao Jing , Cheng Ni , Xue Xiaofeng , Wu Liming , Zhu Xiaohong , Cao Wei
Published: August 2015

HPLC-ECD fingerprints of linden honey samples.
Prediction of analytes' electrophoretic mobility in mixed solvent buffers using Abraham solvation parameters
Authors: Jouyban A. , Fazeli-Bakhtiyari R. , Shayanfar A. , Acree W. E.
Published: August 2015

The electrophoretic mobility of analytes in different solvent compositions of the background electrolyte was calculated using a combined version of a previously developed model with the Abraham solvation model for providing predictive equations.
Mechanism of a one-photon two-electron process in photocatalytic hydrogen evolution from ascorbic acid with a cobalt chlorin complex
Authors: Aoi Shoko , Mase Kentaro , Ohkubo Kei , Fukuzumi Shunichi
Published: August 2015

A one-photon two-electron process was made possible in photocatalytic H2 evolution from ascorbic acid with a cobalt(ii) chlorin complex via electron transfer.
A single nanoparticle-based sensor for hydrogen peroxide (H2O2) via cytochrome c-mediated plasmon resonance energy transfer
Authors: Kim Yura , Park Ji Youn , Kim Hye Young , Lee Minzae , Yi Jongheop , Choi Inhee
Published: August 2015

We report a novel method for H2O2 detection based on a single plasmonic nanoprobe via cytochrome c-mediated plasmon resonance energy transfer.
Confined chromophores in tobacco mosaic virus to mimic green fluorescent protein
Authors: Zhou Quan , Wu Fengchi , Wu Man , Tian Ye , Niu Zhongwei
Published: August 2015

Grafting green fluorescent protein-like chromophores in the 4 nm channel of tobacco mosaic virus greatly enhances its fluorescence emission.
Copper-mediated three-component synthesis of 3-cyanoimidazo[1,2-a]pyridines
Authors: Wen Qiaodong , Lu Ping , Wang Yanguang
Published: August 2015

A copper-mediated three-component approach towards the synthesis of 3-cyanoimidazo[1,2-a]pyridines from 2-aminopyridines, acetophenones and benzyl cyanide was developed. This cascade reaction proceeds through a copper-mediated oxidative release of cyanide from benzyl cyanide, a copper-mediated Ortoleva–King reaction, and a copper-catalyzed cyanation.
Copper-catalyzed oxidative decarboxylative C–H arylation of benzoxazoles with 2-nitrobenzoic acids
Authors: Chen Lijun , Ju Lin , Bustin Katelyn A. , Hoover Jessica M.
Published: August 2015

The first copper-catalyzed oxidative decarboxylative C–H arylation is reported, enabling the direct synthesis of arylated benzoxazoles from 2-nitrobenzoic acids.
Plutonium and transplutonium element trioxides: molecular structures, chemical bonding, and isomers
Authors: Zaitsevskii Andréi
Published: August 2015

The stability of the An·3O (An = Pu through Cf) lowest-energy isomers should decrease in the series Pu(vi)O3 > Am(v)O3 ≈ Bk(v)O3 > Cm(iii)O(O2) > Cf(iii)O(O2).
The onset of electron-induced proton-transfer in hydrated azabenzene cluster anions
Authors: Wang Yi , Zhang Xinxing , Lyapustina Svetlana , Nilles Michael M. , Xu Shoujun , Graham Jacob D. , Bowen Kit H. , Kelly John T. , Tschumper Gregory S. , Hammer Nathan I.
Published: August 2015

The prospect that protons from water may be transferred to N-heterocyclic molecules due to the presence of an excess electron is studied in hydrated azabenzene cluster anions using spectroscopy and computational chemistry.
Electron confinement induced by diluted hydrogen-like ad-atoms in graphene ribbons
Authors: González J. W. , Rosales L. , Pacheco M. , Ayuela A.
Published: August 2015

We report the electronic properties of two-dimensional systems, which are patterned with ad-atoms in two separated regions. By applying band-folding procedures we are able to predict the energies and the spatial distribution of those impurity-induced states.
Infrared spectra reveal box-like structures for a pentamer and hexamer of mixed carbon dioxide–acetylene clusters
Authors: Rezaei Mojtaba , Norooz Oliaee J. , Moazzen-Ahmadi N. , McKellar A. R. W.
Published: August 2015

The hexamer (CO2)4–(C2H2)2 is characterized by its high-resolution infrared spectrum.
Nucleobases tagged to gold nanoclusters cause a mechanistic crossover in the oxidation of CO
Authors: Rai Sandhya , Ehara Masahiro , Deva Priyakumar U.
Published: August 2015

A mechanistic crossover is observed upon using nucleobase tagged gold clusters as catalysts favoring the Eley–Rideal mechanism, over the conventional Langmuir–Hinshelwood pathway followed using pristine gold clusters during CO oxidation.
Simple sodium and potassium phenolates as catalysts for highly isoselective polymerization of rac-lactide
Authors: Dai Zhongran , Sun Yangyang , Xiong Jiao , Pan Xiaobo , Tang Ning , Wu Jincai
Published: August 2015

A series of simple sodium and potassium phenolates can highly isoselectively catalyze the polymerization of rac-lactide (with a high Pm value of up to 0.89).
Syntheses, structures, and1H,13C{1H} and119Sn{1H} NMR chemical shifts of a family of trimethyltin alkoxide, amide, halide and cyclopentadienyl compounds
Authors: Lichtscheidl Alejandro G. , Janicke Michael T. , Scott Brian L. , Nelson Andrew T. , Kiplinger Jaqueline L.
Published: August 2015

The synthesis and full characterization by Nuclear Magnetic Resonance (1H,13C{1H} and119Sn{1H}) of eleven Me3SnX complexes in six common organic solvents is presented.
Strategic review of secondary phases, defects and defect-complexes in kesterite CZTS–Se solar cells
Authors: Kumar Mukesh , Dubey Ashish , Adhikari Nirmal , Venkatesan Swaminathan , Qiao Qiquan
Published: August 2015

This article presents a strategic review of secondary phases, defects and defect-complexes in kesterite CZTS–Se solar cells responsible for performance gap from CIGS solar cells.
Characterization and sources of black carbon in PM2.5at a site close to a roadway in Gwangju, Korea, during winter
Authors: Park Seung Shik , Lee Kwon-Ho
Published: August 2015

Potential source contribution function maps for black carbon (BC) observed at a roadway site indicate that the BC observed during episode “A” was most likely attributed to local emissions, while local sources and regional transport of air masses contributed to the enhanced BC concentrations during episode “B”.
Research highlights: advances and challenges in developing mainstream anammox treatment
Authors: Tan David T. , Shuai Danmeng
Published: August 2015

We highlight recent studies about monitoring and promoting the growth of anammox bacteria in mainstream wastewater treatment.
Precise oxygen scission of lignin derived aryl ethers to quantitatively produce aromatic hydrocarbons in water
Authors: Luo Zhicheng , Wang Yimeng , He Mingyuan , Zhao Chen
Published: August 2015

To produce aromatic hydrocarbons from biomass, a novel route is reported for one-pot selective hydrodeoxygenation of a lignin derived aryl ether mixture to C6–C9 aromatic hydrocarbons over Ru/sulfate zirconia in the aqueous phase.
Centrifugo-pneumatic sedimentation, re-suspension and transport of microparticles
Authors: Zhao Y. , Schwemmer F. , Zehnle S. , von Stetten F. , Zengerle R. , Paust N.
Published: August 2015

The centrifugo-pneumatic particle sedimentation, re-suspension and transport do not require any auxiliary means besides rotation and can be used for magnetic or non-magnetic particles with different particle sizes and densities.
Correction: Synthesis and antibacterial activity evaluation of C-5 side chain modified analogues of FYL-66, a potential agent against methicillin-resistant Staphylococcus aureus
Authors: Yang Xiaoyan , Li Zicheng , Wang Zhenling , Sang Zitai , Long Haiyue , Tang Jianying , Yang Tao , Liu Yuanyuan , Luo Youfu
Published: August 2015

Correction for ‘Synthesis and antibacterial activity evaluation of C-5 side chain modified analogues of FYL-66, a potential agent against methicillin-resistant Staphylococcus aureus’ by Xiaoyan Yang et al., MedChemComm, 2015, 6, 1156–1172.
Targeting copper in cancer therapy: ‘Copper That Cancer’
Authors: Denoyer Delphine , Masaldan Shashank , La Fontaine Sharon , Cater Michael A.
Published: August 2015

Copper coordination compounds target copper in cancer by diverse mechanisms.
Multifaceted core–shell nanoparticles: superparamagnetism and biocompatibility
Authors: Sardar Debasmita , Neogi S. K. , Bandyopadhyay S. , Satpati Biswarup , Ahir Manisha , Adhikary Arghya , Jain Ruchi , Gopinath Chinnakonda S. , Bala Tanushree
Published: August 2015

A facile method for the synthesis of NicoreAgshell and NicoreAushell nanoparticles with suitable surface modification for the latter has been demonstrated with potential applications.
Single layer lead iodide: computational exploration of structural, electronic and optical properties, strain induced band modulation and the role of spin–orbital-coupling
Authors: Zhou Mei , Duan Wenhui , Chen Ying , Du Aijun
Published: August 2015

Graphitic like layered materials exhibit intriguing electronic structures and thus the search for new types of two-dimensional (2D) monolayer materials is of great interest for developing novel nano-devices.
A fluorescence nanosensor for lipase activity: enzyme-regulated quantum dots growth in situ
Authors: Zhang Wei , Liu Jia , Zhang Lei , Gan Jian-hong , Ding Yaqi , Huang Wei , Huo Feng-wei , Tian Danbi
Published: August 2015

A novel analytical assay to detect the lipase activity was based on the enzyme-regulated quantum dots growth in situ.
Non-aqueous template-assisted synthesis of mesoporous nanocrystalline silicon orthophosphate
Authors: Styskalik Ales , Skoda David , Moravec Zdenek , Roupcova Pavla , Barnes Craig E. , Pinkas Jiri
Published: August 2015

Mesoporous nanocrystalline silicon orthophosphate Si5P6O25 was synthesized by the non-hydrolytic sol–gel reaction in the presence of Pluronic P123 template and displays superior catalytic activity and selectivity in methylstyrene dimerization.
A facile synthesis of ZnO/CNT hierarchical microsphere composites with enhanced photocatalytic degradation of methylene blue
Authors: Zhu Guang , Wang Hongyan , Yang Gaoxia , Chen Liangwei , Guo Peijun , Zhang Li
Published: August 2015

Novel carbon nanotube (CNT) and hierarchical ZnO mircosphere composites were prepared via a facile chemical deposition route and their photocatalytic performance in the degradation of methylene blue (MB) was investigated.
A scalable formation of nano-SnO2 anode derived from tin metal–organic frameworks for lithium-ion battery
Authors: Sun Zixu , Cao Can , Han Wei-Qiang
Published: August 2015

In this work, for the first time, we synthesize a SnO2 nanomaterial through the calcination of tin metal–organic framework (MOF) precursors.
Controllable graphene coated mesoporous carbon/sulfur composite for lithium–sulfur batteries
Authors: Chen Shanliang , Tang Qunli , Chen Xiaohua , Hu Aiping , Deng Weina , Liu Zheng
Published: August 2015

We present the construction of a CMK-3/S composite which is controllably coated with grapheneviathe functionalization of the CMK-3 surface with the assistance of a bridging agent (l-lysine and PEG).
Pseudotannins self-assembled into antioxidant complexes
Authors: Cheng H. A. , Drinnan C. T. , Pleshko N. , Fisher O. Z.
Published: August 2015

The chemical structure of tannic acid and the theoretical structure of pseudotannins.
Using solution state NMR spectroscopy to probe NMR invisible gelators
Authors: Wallace Matthew , Iggo Jonathan A. , Adams Dave J.
Published: August 2015

Changes in charge, hydrophobicity and arrangement of supramolecular aggregates can be followed throughout the assembly process by measuring residual quadrupolar couplings of molecular probes.
Molecular dynamics simulations on lithium diffusion in LiFePO4: the effect of anti-site defects
Authors: Hu Boyang , Tao Guohua
Published: August 2015

MD simulations show that anti-site defect aggregation in LiFePO4allows defect recombination and inter-channel crossings, resulting in heterogeneous diffusion.
Systematic evaluation of natural scaffolds in cutaneous wound healing
Authors: Cam Cynthia , Zhu Suwei , Truong Norman F. , Scumpia Philip O. , Segura Tatiana
Published: August 2015

In this report, we show the tissue healing capacity for solely conductive scaffolds composed of fibrin and/or hyaluronic acid and compared them to scaffolds that deliver a proangiogenic protein signal.
Spontaneous helical structure formation in laminin nanofibers
Authors: Szymanski John M. , Ba Mengchen , Feinberg Adam W.
Published: August 2015

Surface-initiated assembly is used to engineer laminin nanofibers that spontaneously adopt a helical conformation.
Low-temperature grown wurtzite InxGa1−xN thin films via hollow cathode plasma-assisted atomic layer deposition
Authors: Haider Ali , Kizir Seda , Ozgit-Akgun Cagla , Goldenberg Eda , Leghari Shahid Ali , Okyay Ali Kemal , Biyikli Necmi
Published: August 2015

Hollow cathode plasma assisted atomic layer deposited InxGa1−xN alloys show successful tunability of the optical band gap by changing the In concentration in a wide range.
Generalised look‐up table concept for direct torque control in induction drives with multilevel inverters
Authors: Brando Gianluca , Dannier Adolfo , Del Pizzo Andrea , Rizzo Renato , Spina Ivan
Published: August 2015

This study deals with direct torque control (DTC) of induction motor drives when a multilevel inverter is involved. The proposed control technique is finalised to reduce the amplitude of torque oscillations and to improve the motor dynamic response regardless of operating speed conditions while assuring a satisfactory input current distortion. This is achieved by using a special look‐up‐table built with a novel approach. The control itself is based on the application in each sampling interval of one or two voltage vectors suitably selected, in order to ensure low electromagnetic torque ripple in steady‐state operations and fast dynamic behaviour in transient operations. In the algorithm, the converter voltage vectors selection is carried out by using a novel look‐up table whose entry points are computed by means of a specialised relation, starting from the outputs of multilevel hysteresis controllers. The suggested method, suitable for a generic multilevel inverter, is detailed for a neutral point clamped three‐level inverter. The proposed algorithm is validated by several numerical results, and compared with a DTC algorithm based on a traditional three‐speed range look‐up tables. Finally, some experimental results, obtained with a scale laboratory setup, are shown, discussed and compared with the numerical ones.
Rotor parameter determination for the brushless doubly fed (induction) machine
Authors: McMahon Richard , Roberts Paul , Tatlow Mark , Abdi Ehsan , Broekhof Alex , Abdi Salman
Published: August 2015

A procedure has been established for obtaining equivalent circuit parameters for the brushless doubly fed machine, also known as the brushless doubly fed induction machine, by transforming a reduced coupled‐circuit model into a sequence component form. This approach takes advantage of the model reduction procedure's ability to reduce a complex rotor structure to a single equivalent loop without significant loss of accuracy. An alternative method based on winding factors has also been developed and includes coupling via harmonic fields. Parameters determined in both ways are in close agreement with those determined from finite element analysis and experimentally. The advantages of each method are discussed in the conclusion section.
Estimating control delays at signalised intersections using low‐resolution transit bus‐based global positioning system data
Authors: Wang Hua , Zhang Guohui , Zhang Zhisong , Wang Yinhai
Published: August 2015

Intersection control delay is one of the most important performance indicators for evaluating the traffic level of service and intersection capacities. In current traffic data detection infrastructure, control delay is not directly measurable. Although video‐based detection approaches have been applied, their detection accuracy and reliability are constrained by application conditions and detection environments. Manual control delay data collection is labour‐intensive, tedious, and time‐consuming. High‐resolution global positioning system (GPS) data provide an effective means of estimating control delays at intersections, but computationally intensive algorithms and hardware support are needed to handle a large network and impede their wide applications. In this study, a computationally cost‐effective control delay estimation algorithm is developed based on low‐resolution GPS‐based transit bus trajectory data. Transit bus travelling behaviour is formulated to facilitate delay estimation. The effectiveness of the proposed algorithm is examined and verified by the field data and the results indicate that the proposed algorithm provides accurate and reliable control delay estimation at intersections under various conditions.
Dual‐segment S‐shaped aperture‐coupled cylindrical dielectric resonator antenna for X‐band applications
Authors: Majeed Asmaa H. , Abdullah Abdulkareem S. , Elmegri Fauzi , Sayidmarie Khalil Hassan , Abd‐Alhameed Raed A. , Noras James M.
Published: August 2015

A new low‐cost dual‐segmented dielectric resonator (DR) antenna design is proposed for wideband applications in the X‐band region. Two DRs coupled to an S‐shaped slot introduce interesting features. The antenna performance was characterised in terms of the reflection coefficient, gain, and radiation pattern, and detailed simulation studies indicate excellent antenna performance from 7.66 to 11.2 GHz (37.5% fractional bandwidth) with a maximum gain of 6 dBi at 10.6 GHz, whereas the fabricated prototype has a matched bandwidth from 7.8 to 11.85 GHz (41% fractional bandwidth) and maximum gain of 6 dBi. The antenna is compact, size 1 × 0.83 × 0.327 times the wavelength at 10 GHz. The two DR segments may be located on the same side or on opposite sides of the substrate, giving, respectively, improved gain or more uniform field patterns. Experimental testing of the prototype performance showed reasonable agreement with the predicted performance.
On iterative path integral calculations for a system interacting with a shifted dissipative bath
Authors: Walters Peter L. , Banerjee Tuseeta , Makri Nancy
Published: August 2015

Real-time path integral calculations for the propagation of a system in contact with a harmonic dissipative environment often employ the iterative quasi-adiabatic propagator path integral (i-QuAPI) methodology. We compare two simple ways of applying this methodology to a bath initially in equilibrium with the localized state of the system (e.g., the donor in the case of charge transfer). The first way involves modifying the phase of the system via a time-local phase given in terms of integrals of the spectral density or in terms of the coefficients entering the QuAPI-discretized influence functional. In the iterative decomposition of the path integral, this approach requires consistent memory truncation to avoid extremely slow convergence. The second, alternative approach involves shifting the coordinate of the system, to bring the donor state in equilibrium with the bath, and requires no further modification of the i-QuAPI algorithm.
Fundamental aspects of deuterium retention in tungsten at high flux plasma exposure
Authors: Ogorodnikova O. V.
Published: August 2015

An effect of enhanced trapping of deuterium in tungsten at high flux was discovered. It was shown analytically and confirmed experimentally that the deuterium trapping in a presence of high density of defects in tungsten (W) depends on the ion energy and ion flux. Newly developed analytical model explains experimentally observed discrepancy of deuterium trapping at radiation-induced defects in tungsten at different ion fluxes that significantly improves a prediction of hydrogen isotope accumulation in different plasma devices, including ITER and DEMO. The developed model can be used for many system of hydrogen in a metal in both normal and extreme environments (high fluxes, elevated temperatures, neutron irradiation, etc.). This new model allows, for the first time, to validate density function theory (DFT) predictions of multiple occupation of a defect with deuterium against experimental data that bridge the gap in length and time scale between DFT calculations and experiments. By comparing first-principle calculations based on DFT and semi-empirical “adsorption model,” it was proved that the mechanism of hydrogen isotope trapping in a vacancy cluster is similar to a chemisorption on a surface. Binding energies of deuterium with different types of defects in W were defined. Moreover, the surface barrier of deuterium to be chemisorbed on a clean W surface was found to be less than 1 eV and kinetics of deuterium release is limited by de-trapping from defects rather than to be limited by surface effects.
Facet-controlled phase separation in supersaturated Au-Ni nanoparticles upon shape equilibration
Authors: Herz A. , Friák M. , Rossberg D. , Hentschel M. , Theska F. , Wang D. , Holec D. , Šob M. , Schneeweiss O. , Schaaf P.
Published: August 2015

Solid-state dewetting is used to fabricate supersaturated, submicron-sized Au-Ni solid solution particles out of thin Au/Ni bilayers by means of a rapid thermal annealing technique. Phase separation in such particles is studied with respect to their equilibrium crystal (or Wulff) shape by subsequent annealing at elevated temperature. It is found that {100} faceting planes of the equilibrated particles are enriched with Ni and {111} faces with Au. Both phases are considered by quantum-mechanical calculations in combination with an error-reduction scheme that was developed to compensate for a missing exchange-correlation potential that would reliably describe both Au and Ni. The observed phase configuration is then related to the minimization of strongly anisotropic elastic energies of Au- and Ni-rich phases and results in a rather unique nanoparticle composite state that is characterized by nearly uniform value of elastic response to epitaxial strains all over the faceted surface. The same conclusion is yielded also by evaluating bi-axial elastic moduli when employing interpolated experimental elastic constants. This work demonstrates a useful route for studying features of physical metallurgy at the mesoscale.
Structure and dynamics of a layer of sedimented particles
Authors: Sonn-Segev Adar , Bławzdziewicz Jerzy , Wajnryb Eligiusz , Ekiel-Jeżewska Maria L. , Diamant Haim , Roichman Yael
Published: August 2015

We investigate experimentally and theoretically thin layers of colloid particles held adjacent to a solid substrate by gravity. Epifluorescence, confocal, and holographic microscopy, combined with Monte Carlo and hydrodynamic simulations, are applied to infer the height distribution function of particles above the surface, and their diffusion coefficient parallel to it. As the particle area fraction is increased, the height distribution becomes bimodal, indicating the formation of a distinct second layer. In our theory, we treat the suspension as a series of weakly coupled quasi-two-dimensional layers in equilibrium with respect to particle exchange. We experimentally, numerically, and theoretically study the changing occupancies of the layers as the area fraction is increased. The decrease of the particle diffusion coefficient with concentration is found to be weakened by the layering. We demonstrate that particle polydispersity strongly affects the properties of the sedimented layer, because of particle size segregation due to gravity.
The atomic structure of low-index surfaces of the intermetallic compound InPd
Authors: McGuirk G. M. , Ledieu J. , Gaudry É. , de Weerd M.-C. , Hahne M. , Gille P. , Ivarsson D. C. A. , Armbrüster M. , Ardini J. , Held G. , Maccherozzi F. , Bayer A. , Lowe M. , Pussi K. , Diehl R. D. , Fournée V.
Published: August 2015

The intermetallic compound InPd (CsCl type of crystal structure with a broad compositional range) is considered as a candidate catalyst for the steam reforming of methanol. Single crystals of this phase have been grown to study the structure of its three low-index surfaces under ultra-high vacuum conditions, using low energy electron diffraction (LEED), X-ray photoemission spectroscopy (XPS), and scanning tunneling microscopy (STM). During surface preparation, preferential sputtering leads to a depletion of In within the top few layers for all three surfaces. The near-surface regions remain slightly Pd-rich until annealing to ∼580 K. A transition occurs between 580 and 660 K where In segregates towards the surface and the near-surface regions become slightly In-rich above ∼660 K. This transition is accompanied by a sharpening of LEED patterns and formation of flat step-terrace morphology, as observed by STM. Several superstructures have been identified for the different surfaces associated with this process. Annealing to higher temperatures (≥750 K) leads to faceting via thermal etching as shown for the (110) surface, with a bulk In composition close to the In-rich limit of the existence domain of the cubic phase. The Pd-rich InPd(111) is found to be consistent with a Pd-terminated bulk truncation model as shown by dynamical LEED analysis while, after annealing at higher temperature, the In-rich InPd(111) is consistent with an In-terminated bulk truncation, in agreement with density functional theory (DFT) calculations of the relative surface energies. More complex surface structures are observed for the (100) surface. Additionally, individual grains of a polycrystalline sample are characterized by micro-spot XPS and LEED as well as low-energy electron microscopy. Results from both individual grains and “global” measurements are interpreted based on comparison to our single crystals findings, DFT calculations and previous literature.
Thermal-noise suppression in nano-scale Si field-effect transistors by feedback control based on single-electron detection
Authors: Chida Kensaku , Nishiguchi Katsuhiko , Yamahata Gento , Tanaka Hirotaka , Fujiwara Akira
Published: August 2015

We perform feedback (FB) control for suppressing thermal fluctuation in the number of electrons in a silicon single-electron (SE) device composed of a small transistor and capacitor. SEs enter and leave the capacitor via the transistor randomly at thermal equilibrium, which is monitored in real time using a high-charge-sensitivity detector. In order to suppress such random motion or thermal fluctuation of the electrons, SEs are injected and removed using the transistor according to the monitored change in the number of electrons in the capacitor, which is exactly the FB control. As a result, thermal fluctuation in the number of electrons in a SE device is suppressed by 60%, which corresponds to the so-called FB cooling from 300 to 110 K. Moreover, a thermodynamics analysis of this FB cooling reveals that entropy in the capacitor is reduced and the device is at non-equilibrium; i.e., the free energy of the device increases. Since this entropy reduction originates from information about the electrons' motion monitored by the detector, our results by the FB control represent one type of information-to-energy conversion.
Effective doping of low energy ions into superfluid helium droplets
Authors: Zhang Jie , Chen Lei , Freund William M. , Kong Wei
Published: August 2015

We report a facile method of doping cations from an electrospray ionization (ESI) source into superfluid helium droplets. By decelerating and stopping the ion pulse of reserpine and substance P from an ESI source in the path of the droplet beam, about 104 ion-doped droplets (one ion per droplet) can be recorded, corresponding to a pickup efficiency of nearly 1 out of 1000 ions. We attribute the success of this simple approach to the long residence time of the cations in the droplet beam. The resulting size of the doped droplets, on the order of 105/droplet, is measured using deflection and retardation methods. Our method does not require an ion trap in the doping region, which significantly simplifies the experimental setup and procedure for future spectroscopic and diffraction studies.
Electron attachment and positive ion chemistry of monohydrogenated fluorocarbon radicals
Authors: Wiens Justin P. , Shuman Nicholas S. , Miller Thomas M. , Viggiano Albert A.
Published: August 2015

Rate coefficients and product branching fractions for electron attachment and for reaction with Ar+ are measured over the temperature range 300–585 K for three monohydrogenated fluorocarbon (HFC) radicals (CF3CHF, CHF2CF2, and CF3CHFCF2), as well as their five closed-shell precursors (1-HC2F4I, 2-HC2F4I, 2-HC2F4Br, 1-HC3F6I, 2-HC3F6Br). Attachment to the HFC radicals is always fairly inefficient (between 0.1% and 10% of the Vogt–Wannier capture rate), but generally faster than attachment to analogous perfluorinated carbon radicals. The primary products in all cases are HF-loss to yield CnFm−1− anions, with only a minor branching to F− product. In all cases the temperature dependences are weak. Attachment to the precursor halocarbons is near the capture rate with a slight negative temperature dependence in all cases except for 2-HC2F4Br, which is ∼10% efficient at 300 K and becomes more efficient, approaching the capture rate at higher temperatures. All attachment kinetics are successfully reproduced using a kinetic modeling approach. Reaction of the HFC radicals with Ar+ proceeds at or near the calculated collisional rate coefficient in all cases, yielding a wide variety of product ions.
Turbulent energy density and its transport equation in scale space
Authors: Hamba Fujihiro
Published: August 2015

The energy spectrum contains information not only on the intensity but also on the scale dependence of the turbulent fluctuations; the spectrum is commonly used to describe the dynamics of homogeneous isotropic turbulence. On the other hand, one-point statistical quantities such as the turbulent kinetic energy are mainly treated for inhomogeneous turbulence. Although the energy spectrum must be useful in describing the scale dependence of inhomogeneous turbulence, the Fourier transform cannot be performed in general cases. In this work, instead of the energy spectrum in the wavenumber space, the energy density in the scale space was introduced on the basis of the two-point velocity correlation in the physical space. The transport equation for the energy density was derived for inhomogeneous turbulence. Direct numerical simulation (DNS) data of homogeneous isotropic turbulence were first used to evaluate the energy transfer in the scale space. The energy density equation was compared with the energy spectrum equation to assess the role of the energy density. DNS data of turbulent channel flow were also used to evaluate the energy density equation for inhomogeneous turbulence. The energy transport in the physical and scale spaces was examined in different regions of channel flow. It was shown that the transport equation for the energy density adequately describes the energy transfer in the scale space. The energy flux from the large to the small scales was observed for both turbulent flows in a similar manner to the conventional energy cascade in the wavenumber space.
Making sense of the conflicting magic numbers in WSin clusters
Authors: Abreu Marissa Baddick , Reber Arthur C. , Khanna Shiv N.
Published: August 2015

First principles studies on the geometric structure, stability, and electronic structure of WSin clusters, n = 6-16, have been carried out to show that the observed differing “magic sizes” for WSin clusters are associated with the nature of the growth processes. The WSi12 cluster, observed as a magic species in experiments reacting transition metal ions with silane, is not stable due to a filled shell of 18 electrons, as previously proposed, but due to its atomic structure that arrests further growth because of an endohedral transition metal site. In fact, it is found that all of these clusters, n = 6-16, have filled 5d shells except for WSi12, which has a 5d8 configuration that is caused by crystal field splitting. The stability of WSi15+, observed as highly stable in clusters generated by vaporizing silicon and metal carbonyls, is shown to be associated with a combination of geometric and electronic features. The findings are compared with previous results on CrSin clusters.
Steady state and modulated heat conduction in layered systems predicted by the analytical solution of the phonon Boltzmann transport equation
Authors: Ordonez-Miranda Jose , Yang Ronggui , Volz Sebastian , Alvarado-Gil J. J.
Published: August 2015

Based on the phonon Boltzmann transport equation under the relaxation time approximation, analytical expressions for the temperature profiles of both the steady state and modulated heat conduction inside a thin film deposited on a substrate are derived and analyzed. It is shown that these components of the temperature depend strongly on the ratio between the film thickness and the average phonon mean free path (MFP), and they exhibit the diffusive behavior as predicted by the Fourier's law of heat conduction when this ratio is much larger than unity. In contrast, in the ballistic regime when this ratio is comparable to or smaller than unity, the steady-state temperature tends to be independent of position, while the amplitude and the phase of the modulated temperature appear to be lower than those determined by the Fourier's law. Furthermore, we derive an invariant of heat conduction and a simple formula for the cross-plane thermal conductivity of dielectric thin films, which could be a useful guide for understanding and optimizing the thermal performance of the layered systems. This work represents the Boltzmann transport equation-based extension of the Rosencwaig and Gersho work [J. Appl. Phys. 47, 64 (1976)], which is based on the Fourier's law and has widely been used as the theoretical framework for the development of photoacoustic and photothermal techniques. This work might shed some light on developing a theoretical basis for the determination of the phonon MFP and relaxation time using ultrafast laser-based transient heating techniques.
Modulational instability of ion-acoustic waves in plasma with a q-nonextensive nonthermal electron velocity distribution
Authors: Bouzit Omar , Tribeche Mouloud , Bains A. S.
Published: August 2015

Modulation instability of ion-acoustic waves (IAWs) is investigated in a collisionless unmagnetized one dimensional plasma, containing positive ions and electrons following the mixed nonextensive nonthermal distribution [Tribeche et al., Phys. Rev. E 85, 037401 (2012)]. Using the reductive perturbation technique, a nonlinear Schrödinger equation which governs the modulation instability of the IAWs is obtained. Valid range of plasma parameters has been fixed and their effects on the modulational instability discussed in detail. We find that the plasma supports both bright and dark solutions. The valid domain for the wave number k where instabilities set in varies with both nonextensive parameter q as well as non thermal parameter α. Moreover, the analysis is extended for the rational solutions of IAWs in the instability regime. Present study is useful for the understanding of IAWs in the region where such mixed distribution may exist.
Ferroelectric ordering and magnetoelectric effect of pristine and Ho-doped orthorhombic DyMnO3 by dielectric studies
Authors: Magesh J. , Murugavel P. , Mangalam R. V. K. , Singh K. , Simon Ch. , Prellier W.
Published: August 2015

In this paper, the magnetoelectric coupling and ferroelectric ordering of the orthorhombic Dy1-xHoxMnO3 (x = 0 and 0.1) are studied from the magnetodielectric response of the polycrystalline samples. The dielectric study on the DyMnO3 reveals ferroelectric transition at 18 K along with an addition transition at 12 K. We suggest that the transition at 12 K could have originated from the polarization flop rather than being the rare earth magnetic ordering. The magnetodielectric study reveals a magnetoelectric coupling strength of 10%, which is stronger by two orders of magnitude in comparison to the hexagonal manganites. Surprisingly, the Ho3+ substitution in DyMnO3 suppresses the magnetoelectric coupling strength via the suppression of the spiral magnetic ordering. In addition, it also reduces the antiferromagnetic ordering and ferroelectric ordering temperatures. Overall, the studies show that the rare earth plays an important role in the magnetoelectric coupling strength through the modulation of spiral magnetic structure.
Wideband slow light in microfiber double-knot resonator with a parallel structure
Authors: Xu Yi-Ping , Ren Li-Yong , Liang Jian , Ma Cheng-Ju , Wang Ying-Li , Kong Xu-Dong , Lin Xiao
Published: August 2015

The characteristics of slow light in the microfiber double-knot resonator with a parallel structure are investigated both theoretically and experimentally. It is predicted that a wide bandwidth of about 20 GHz and flat-top group delay of about 70 ps can be generated in this resonator by changing the coupling coefficient. In the experiment, such a resonator was fabricated and the slow-light effect was demonstrated. As a result, when a pulse with a bandwidth of 3.35 GHz (equivalent to the temporal width of 299 ps) was launched into the resonator, a large group delay, whose average value was about 69.4 ps with a flat-top wavelength bandwidth of about 190 pm, was achieved.
Lateral electric-field control of giant magnetoresistance in Co/Cu/Fe/BaTiO3 multiferroic heterostructure
Authors: Savitha Pillai S. , Kojima H. , Itoh M. , Taniyama T.
Published: August 2015

We report lateral electric-field-driven sizable changes in the magnetoresistance of Co/Cu/Fe tri-layered wires on BaTiO3 single crystal. While the observed change is marginal in the tetragonal phase of BaTiO3, it reaches over 40% in the orthorhombic and rhombohedral phases with an electric field of 66 kV/cm. We attribute it to possible electric-field-induced variations of the spin-dependent electronic structures, i.e., spin polarization, of the Fe via interfacial strain transfer from BaTiO3. The contrasting results for the different phases of BaTiO3 are discussed, associated with the distinct aspects of the ferroelectric polarization switching processes in each phase.
Quantitative evaluation of inhomogeneous device operation in thin film solar cells by luminescence imaging
Authors: Seeland Marco , Kästner Christian , Hoppe Harald
Published: August 2015

We present a method for quantitative evaluation of electroluminescence images from thin film solar cells. The method called “quantitative electroluminescence imaging” (QuELI) is based on decoupling local equivalent circuit parameters and allows calculation of the local current-density as well as the local series resistance and saturation current-density. By application of this method to electroluminescence images obtained from polymer-fullerene based solar cells, we show that QuELI allows efficient separation between: (a) properties of the electrodes and their associated interfaces by the local series resistance and (b) properties of the active layer by the saturation current-density. We furthermore reveal large scale lateral phase separation via the strong variation in the saturation current-density, which delivers information on the energetic difference of thermal activation of charge carriers across the effective active band gap.
Serial femtosecond X-ray diffraction of enveloped virus microcrystals
Authors: Lawrence Robert M. , Conrad Chelsie E. , Zatsepin Nadia A. , Grant Thomas D. , Liu Haiguang , James Daniel , Nelson Garrett , Subramanian Ganesh , Aquila Andrew , Hunter Mark S. , Liang Mengning , Boutet Sébastien , Coe Jesse , Spence John C. H. , Weierstall Uwe , Liu Wei , Fromme Petra , Cherezov Vadim , Hogue Brenda G.
Published: August 2015

Serial femtosecond crystallography (SFX) using X-ray free-electron lasers has produced high-resolution, room temperature, time-resolved protein structures. We report preliminary SFX of Sindbis virus, an enveloped icosahedral RNA virus with ∼700 Å diameter. Microcrystals delivered in viscous agarose medium diffracted to ∼40 Å resolution. Small-angle diffuse X-ray scattering overlaid Bragg peaks and analysis suggests this results from molecular transforms of individual particles. Viral proteins undergo structural changes during entry and infection, which could, in principle, be studied with SFX. This is an important step toward determining room temperature structures from virus microcrystals that may enable time-resolved studies of enveloped viruses.