bluuebunny/crossref_metadata_2025 huggingface dataset:
Radio and Gamma-ray emission in nearby BL Lacs
Authors: Giovannini G. , Liuzzo E. , Boccardi B. , Giroletti M.
Published: July 2014

The advent of Fermi is changing our understanding on the radio and γ-ray emission in active galactic nuclei. Unlike pre-Fermi ideas, BL Lac objects are found to be the most abundant emitters in the γ-ray band. However, since they are relatively weak radio sources, most of their parsec-scale structure and their multifrequency properties are poorly understood and/or have not been investigated in a systematic fashion. Here we are analyzing the radio and γ-ray emission properties of a sample of 42 BL Lacs selected with no constraint on their radio and γ-ray emission. Thanks to new Very Long Baseline Array observations at 8 and 15 GHz for the whole sample, we discuss their parsec-scale structure. Parsec-scale radio emission is observed in the majority of the sources at both frequencies. The comparison between our results in radio and gamma-ray bands points out the presence of a large number of faint BL Lacs showing “non-classical” properties such as low source compactness, low core dominance, no gamma-ray emission.
Knowledge Discovery workflows for the classification of AGNs in multiwavelength spaces: the Blazars case
Authors: D'Abrusco Raffaele , Massaro F. , Paggi A. , Fabbiano G.
Published: July 2014

The development of new AGNs selection techniques based on the massive multi-wavelength datasets that are becoming more and more frequent in astronomy is a crucial task to gather statistically significant samples and shed light on the physical nature of this diverse class of extragalactic sources. Novel characterizations of specific classes of sources from unexplored region of their spectrum and unusual combinations of the observational parameters can translate into new classification criteria. In this innovative data environment, the whole process ranging from the discovery of new patterns to the application of such patters to the selection of new AGNs, has to be tackled using a Knowledge Discovery (KD) workflow. A KD workflows is a combination of different KD methods that automatically extract the more interesting patters from data, reduce the complexity of the dataset and provide astronomers with the simplest possible amount of information to be interpreted. In this talk, I will describe an original KD workflow which, in one of its first applications, has led to the discovery of a previously unknown peculiar pattern followed by blazars in the mid-Infrared color space (the blazars WISE locus), and the development of a new classification criterion based on this pattern and useful to tackle different problems. The comprehensive KD workflow used to derive these results encompasses unsupervised methods for the exploration of the multi-dimensional observable spaces, and supervised method for the training and optimization of classifiers based on the patterns determined in the observable spaces. In particular, I will describe the new methods for the association of unidentified gamma-ray sources and the extraction of candidate blazars from mid-Infrared photometric catalog based on the WISE blazars locus.
The central pc-scale region in blazars: insights from multi-band observations
Authors: Arshakian Tigran G. , Chavushyan Vahram
Published: July 2014

The empirical relations in the black hole-accretion disk-relativistic jet system and physical processes behind these relations are still poorly understood, partly because they operate close to the black hole within the central light year. Very long baseline array (VLBA) provides unparalleled resolution at 15 GHz with which to observe the jet components at sub-milliarcsecond scales, corresponding to sub-pc-scales for local blazars. We discuss the jet inner structure of blazars, location and radiation mechanisms operating in the innermost parsec-scale region of blazars, and evidence for jet-excited broad-line region (BLR) ouflowing downstream the jet. Outflowing BLR can provide necessary conditions for production of high energy emission along the jet between the base of the jet and the BLR and far beyond the BLR as evidenced by recent observations. Flat spectrum quasars and low synchrotron peaked sources are the most likely objects to host the outfllowing BLR. From the γ-ray absorption arguments, we propose that the jet-excited region of the outflowing BLR in quasars is small and/or gas filling factor is low, and that the orientation and opening angle of the outflowing BLR can lead to relevant γ-ray absorption features observed in quasars.
230 years of AGN monitoring: Frequency of cloud occultation events in AGN & constraints for clumpy torus models
Authors: Krumpe Mirko , Markowitz A. , Nikutta R.
Published: July 2014

We systematically search for discrete absorption events in the vast archive of the Rossi X-ray Timing Explorer. This includes dozens of nearby type I and Compton-thin type II AGN and covers timescales from days to over a decade for individual objects. We are sensitive to discrete absorption events due to clouds of full-covering, neutral or mildly-ionized gas with columns 1022−25 cm−2 transiting the line of sight. We detect 13 eclipse events in 8 objects, roughly tripling the number of previously published events from this archive. Despite sensitivity to events with NH up to 1024−25 cm−2, we measured no Compton-thick eclipses in our sample. Peak column densities span 2.5–19 × 1022 cm−2. Event durations span hours to months. We infer the clouds distances from the black hole, assuming Keplerian motion, to span 0.2–80 × 104 Schwarzschild radii. We find no statistically significant difference between the individual cloud properties of type I and II objects. The presence of eclipses in both type Is and IIs argues against sharp-edged cloud distributions. The type II AGN show a level of “base-line” X-ray absorption that is consistent with being constant over timescales from 0.6 to 8.4 yr. This can either be explained by a homogeneous medium, or by X-ray-absorbing clouds that each have NH ≪ 1022 cm−2. Considering the “selection function” of the monitoring, we derive the probability of cloud occultation events. Finally, we derive the first X-ray statistical constraints for clumpy-torus models.
The kinematically decoupled core of MCG–6-30-15
Authors: Raimundo Sandra I.
Published: July 2014

The Seyfert galaxy MCG–6-30-15 has recently been observed in the infrared using SINFONI on the VLT, reaching a very high spatial resolution of 0.1 arcsec. This allowed us for the first time to detect a stellar kinematically decoupled core in the inner r < 125 pc of the galaxy. Here we summarise the main theories for the formation of the decoupled core and the implications on the study of this galaxy.
The nature of LINER galaxies: Ubiquitous hot old stars and rare accreting black holes
Authors: Singh R. , van de Ven G. , Jahnke K. ,   the CALIFA collaboration
Published: July 2014

Galaxies, which often contain ionised gas, sometimes also exhibit a so-called low-ionisation nuclear emission line region (LINER). For 30 years, this was attributed to a central mass-accreting supermassive black hole (more commonly known as active galactic nucleus or AGN) of low luminosity, making LINER galaxies the largest AGN sub-population, which dominate in numbers over higher AGN-luminosity Seyfert galaxies and quasars. This, however, poses a serious problem. While the inferred energy balance is plausible, many LINERs clearly do not contain any other independent signatures of an AGN. Using integral field spectroscopic data from the CALIFA survey, we compare the observed radial surface brightness profiles with what is expected from illumination by an AGN. For 48 galaxies with LINER-like emission we show, that the radial emission-line surface brightness profiles are inconsistent with ionisation by a central point-source and hence cannot be due to an AGN alone. The most probable explanation for the excess LINER-like emission is ionisation by evolved stars during the short but very hot and energetic phase known as post-AGB. This leads us to an entirely new interpretation. Post-AGB stars are ubiquitous and their ionising effect should be potentially observable in every galaxy with gas present and with stars older than ~1 Gyr, unless a stronger radiation field from young hot stars or an AGN outshines them. This means, that galaxies with LINER-like emission are not a class defined by a property but rather by the absence of a property. It also explains why LINER emission is observed mostly in massive galaxies with old stars and little star formation.
Study of Spectral Energy Distributions of low-luminosity radio galaxies at z ~ 1–3: a high-z view of the host/AGN connection
Authors: Baldi Ranieri D. , Chiaberge Marco , Capetti Alessandro
Published: July 2014

Low-luminosity radio galaxies, common in the local Universe, are associated with giant elliptical galaxies and typically with a FR I radio morphology. However, they are rare in flux-limited samples of distant radio-loud (RL) AGN due to a selection bias. Chiaberge et al. (2009) selected the first sizeable sample of FRI candidates at 1<z<3, in the COSMOS field. We study the Spectral Energy Distributions (SEDs) of this low radio power sample from the far-UV to the Mid-IR wavelengths. Our results show that the hosts of these high-z low-luminosity radio sources are old massive galaxies, similar to the local FR Is. However, for half of the sample the UV and MIR excesses indicate the possible significant contribution from star formation and/or nuclear activity, not seen in low-z FR Is. Our sources display a wide variety of properties: from possible quasars at the highest luminosities, to low-luminosity old galaxies.
X-ray variability in LINERs
Authors: Masegosa Josefa , Hernández-García Lorena , Márquez Isabel , González-Martín Omaira
Published: July 2014

One of the most important features in active galactic nuclei (AGN) is the variability of their emission. Variability has been discovered at X-ray, UV, and radio frequencies on time scales from hours to years. Among the AGN family and according to theoretical studies, Low-Ionization Nuclear Emission Line Region (LINER) nuclei would be variable objects on long time scales. Our purpose is to investigate spectral X-ray variability in LINERs and to understand the nature of these kinds of objects, as well as their accretion mechanism.ChandraandXMM–Newton public archives were used to compile X-ray spectra of LINER nuclei at different epochs with time scales of years. To search for variability we fit all the spectra from the same object with a set of models, in order to identify the parameters responsible for the variability pattern. We found that long term spectral variability is very common, with variations mostly related to hard energies (2-10 keV). These variations are due to changes in the soft excess, and/or changes in the absorber, and/or intrinsic variations of the source.
Showing the path to path dependence: the habitual path
Authors: Sarigil Zeki
Published: July 2014

This article investigates the conceptual and theoretical implications of the logic of habit for the path-dependence approach. In the existing literature, we see two different logics of action associated with two distinct models of path dependence: the logic of consequences (instrumental rationality) is linked with utilitarian paths (i.e. increasing returns) and the logic of appropriateness (normative rationality) constitutes normative paths (normative lock-in). However, this study suggests that despite its popularity, the path-dependence approach remains underspecified owing to its exclusion or neglect of the logic of habit, which constitutes a distinct mechanism of reproduction or self-reinforcement in the institutional world. This article, therefore, introduces the notion of the ‘habitual path’ as a different model of path dependence. Although the idea of the habitual path is complementary with the existing models, owing to its distinctive notions of agency and mechanisms of path reproduction, it offers a different interpretation of continuity or regularity. Thus, by enriching the path-dependence approach, the notion of the habitual path would contribute to our comprehension of continuities and discontinuities in the political world.
Multiband-coupled sectoral antenna using high and low dielectric constant substrates
Authors: Kandwal Abhishek , Chauhan Jai Verdhan , Khah Sunil Kumar
Published: July 2014

Design analysis of multiband-coupled stacked sectoral antenna array with finite ground plane using high low dielectric constant substrates is proposed in this paper for modern communication systems and applied physics. Multiband planar antennas have been extensively developed due to demands for integration of wireless communication systems. In this paper, we present the design and development of a multiband microstrip antenna array with parasitic coupling and stacking using two different substrates. The stacked designed antenna resonates at three different frequencies: 3.8, 5.4, and 10 GHz; therefore, showing a multiband property with good radiation (far-field) characteristics. A significant comparison study is also presented considering different dielectric constant substrates. The proposed antenna is an attractive solution for different wireless communication systems such as mobile systems, satellite systems, etc.
Factorial Invariance of the DASS-21 Among Adolescents in Four Countries
Authors: Mellor David , Vinet Eugenia V. , Xu Xiaoyan , Hidayah Bt Mamat Norul , Richardson Ben , Román Francisca
Published: July 2014

The use of scales to measure constructs in populations or contexts other than that in which they were established is highly controversial. Despite this, the use of scales without reference to “local” psychometric data is still widespread. In this study we examined the factor structure of the short 21-item form of the Depression, Anxiety, and Stress Scales (DASS-21), when it was applied to adolescent samples recruited from high schools in Australia (N = 371), Chile (N = 448), China (N = 558), and Malaysia (N = 388). Multigroup confirmatory factor analyses revealed that the purported three-factor structure of the DASS-21 was supported in each location with structural invariance across locations. While convergent and divergent validity studies are required to support this finding, the DASS-21 appears to be suitable for use with adolescents in these locations.
Mind Reading Using Neuroimaging
Authors: Gamer Matthias
Published: July 2014

Traditional lie detection tools, such as the polygraph, voice stress analysis, or special interrogation techniques, rely on behavioral or psychophysiological manifestations of deception. With the advent of neuroimaging techniques, the question emerged whether it would be possible to directly identify deceit in the part of the body where it is generated: the brain. After a few promising studies, these techniques became soon commercially available and there have been attempts to use such results in the court in recent years. The current article reviews the development of neuroimaging techniques in the field of deception detection and critically discusses the potential but also the shortcomings of such methods. Unfortunately, the majority of research in this field was rather unsystematic and neglected the accumulated knowledge regarding methodological pitfalls that were extensively discussed in the scientific community in conjunction with the polygraph. Therefore, neuroimaging studies on deception largely differ with respect to the experimental paradigm (the interrogation technique), the methods for analyzing the data, and the procedures to obtain individual diagnoses. Moreover, most studies used artificial laboratory settings that differ considerably from real-life applications. As a consequence, neuroimaging techniques are not applicable for detecting deception in individual field cases at the moment. However, recent advantages such as multivariate pattern analysis might yield novel neuroimaging applications in the near future that are capable of improving established techniques for detecting deception or concealed knowledge.
Quantifying separation and similarity in a Saccharomyces cerevisiae metapopulation
Authors: Knight Sarah , Goddard Matthew R
Published: July 2014

Eukaryotic microbes are key ecosystem drivers; however, we have little theory and few data elucidating the processes influencing their observed population patterns. Here we provide an in-depth quantitative analysis of population separation and similarity in the yeast Saccharomyces cerevisiae with the aim of providing a more detailed account of the population processes occurring in microbes. Over 10 000 individual isolates were collected from native plants, vineyards and spontaneous ferments of fruit from six major regions spanning 1000 km across New Zealand. From these, hundreds of S. cerevisiae genotypes were obtained, and using a suite of analytical methods we provide comprehensive quantitative estimates for both population structure and rates of gene flow or migration. No genetic differentiation was detected within geographic regions, even between populations inhabiting native forests and vineyards. We do, however, reveal a picture of national population structure at scales above ∼100 km with distinctive populations in the more remote Nelson and Central Otago regions primarily contributing to this. In addition, differential degrees of connectivity between regional populations are observed and correlate with the movement of fruit by the New Zealand wine industry. This suggests some anthropogenic influence on these observed population patterns.
A DNA-templated synthesis of encoded small molecules by DNA self-assembly
Authors: Cao Cheng , Zhao Peng , Li Ze , Chen Zitian , Huang Yanyi , Bai Yu , Li Xiaoyu
Published: July 2014

Encoded libraries can be prepared by DNA-templated synthesis without any DNA template.
Measuring whole genome methylation via oxygen channelling chemistry
Authors: Wee Eugene J. H. , Trau Matt
Published: July 2014

Successful use of demethylating drugs in cancers underscores the need for new approaches to analyze whole genome methylation. MBD enrichment coupled to oxygen channeling chemistry-based detection may offer a simple and rapid solution with low sample requirement.
Controllable atmospheric pressure growth of mono-layer, bi-layer and tri-layer graphene
Authors: Li Jing , Ji Hengxing , Zhang Xing , Wang Xuanyun , Jin Zhi , Wang Dong , Wan Li-Jun
Published: July 2014

A coherent three-step growth method has been developed for mono-, bi- and tri-layer graphene with coverage of ∼90% at atmospheric pressure on Cu foil.
Live imaging of cellular dynamics using a multi-imaging vector in single cells
Authors: Park Kyoungsook , Jeong Jinyoung , Chung Bong Hyun
Published: July 2014

A multi-imaging vector system based on 2A peptides is developed for real-time monitoring of cellular dynamics.
Melting point–solubility–structure correlations in multicomponent crystals containing fumaric or adipic acid
Authors: Batisai Eustina , Ayamine Alban , Kilinkissa Ornella E. Y. , Báthori Nikoletta B.
Published: July 2014

The relationships between the melting point, solubility and structure was investigated in a series of multicomponent crystals of fumaric and adipic acid.
Electronic structure study of Ce1−xAxO2 (A = Zr & Hf) nanoparticles: NEXAFS and EXAFS investigations
Authors: Sharma Aditya , Varshney Mayora , Shin Hyun-Joon , Park Yong Jun , Kim Min-Gyu , Ha Tae-Kyun , Chae Keun Hwa , Gautam Sanjeev
Published: July 2014

4f-occupation, Ce+3/Ce+4 ratio and grain-size effects in Zr- and Hf-substituted CeO2 nanoparticles are investigated by NEAXFS and EXAFS.
Connecting carbon nanotubes to polyoxometalate clusters for engineering high-performance anode materials
Authors: Chen Wei , Huang Lujiang , Hu Jun , Li Tengfei , Jia Feifei , Song Yu-Fei
Published: July 2014

Carbon nanotubes (CNTs) possess excellent structural and electronic properties and have been widely investigated as anode materials. Covalent modification of carbon nanotubes (CNTs) with organosilica-containing polyoxometalate (POM) leads to the formation of the nanocomposite CNTs–SiW11 with high discharge capacity, good capacity retention and cycling stability.
A facile and rapid route for the synthesis of Cu/Cu2O nanoparticles and their application in the Sonogashira coupling reaction of acyl chlorides with terminal alkynes
Authors: Bhosale Manohar A. , Sasaki Takehiko , Bhanage Bhalchandra M.
Published: July 2014

This work reports a simple, rapid and efficient protocol for synthesis of Cu/Cu2O nanoparticles. The prepared Cu/Cu2O nanoparticles were effectively utilized for Sonogashira coupling reaction of acyl chlorides with terminal alkynes.
Novel approach for a cerium-based highly-efficient catalyst with excellent NH3-SCR performance
Authors: Huang Haili , Shan Wenpo , Yang Shijian , Zhang Jinhua
Published: July 2014

A highly-efficient NH3-SCR catalyst, CeO2/WO3–TiO2, was prepared by a novel stepwise precipitation approach. This catalyst showed excellent catalytic performance with superior low-temperature activity, high N2 selectivity and a broad operational temperature window.
A simple and convenient approach for preparing core–shell-like silica@nickel species nanoparticles: highly efficient and stable catalyst for the dehydrogenation of 1,2-cyclohexanediol to catechol
Authors: Chen Bao-Hui , Liu Wei , Li An , Liu Ya-Juan , Chao Zi-Sheng
Published: July 2014

A simple and convenient approach for the preparation of core–shell-like silica@nickel species nanoparticles.
Grape seed extract improves epithelial structure and suppresses inflammation in ileum of IL-10-deficient mice
Authors: Yang Guan , Wang Hui , Kang Yifei , Zhu Mei-Jun
Published: July 2014

Defect in intestinal epithelial structure is a critical etiological factor of several intestinal diseases such as inflammatory bowel disease.
Field-flow fractionation with inductively coupled plasma mass spectrometry: past, present, and future
Authors: M-M Pornwilard , Siripinyanond Atitaya
Published: July 2014

Historical background, recent applications, and the future trends of field-flow fractionation-inductively coupled plasma mass spectrometry.
Chemical-assisted femtosecond laser writing of lab-in-fibers
Authors: Haque Moez , Lee Kenneth K. C. , Ho Stephen , Fernandes Luís A. , Herman Peter R.
Published: July 2014

Femtosecond laser writing followed by chemical etching enabled integrated optofluidic devices to form inside and connect to optical fiber waveguides, underlying a new “lab-in-fiber” platform.
Discovery of novel guanidinophenylpyrazole human acrosin inhibitors by molecular hybridization
Authors: Zhao Juntao , Sun Nannan , Gao Yue , Lv Diya , Liu Yang , Jiang Yan , Dong Guoqiang , Chen Qianqian , Li Wei , Zhou Youjun , Zhu Ju , Sheng Chunquan , Lv Jiaguo
Published: July 2014

Novel human acrosin inhibitor F3 was rationally designed by molecular hybridization of the phenylpyrazole and guanidinobenzoate inhibitors.
Facile hydroxyl-assisted synthesis of morphological Cu2O architectures and their shape-dependent photocatalytic performances
Authors: Tang Linli , Lv Jian , Sun Shaodong , Zhang Xiaozhe , Kong Chuncai , Song Xiaoping , Yang Zhimao
Published: July 2014

A facile hydroxyl-assisted synthesis of morphological Cu2O architectures has been demonstrated, and these polyhedral Cu2O manifest shape-dependent properties.
Synthesis and properties of hybrid core–shell poly(alkyltrialkoxysiloxane) latex
Authors: Liu Bo , Huang Shiqiang , Xu Zushun , Gao Feng , Zhu Jie
Published: July 2014

We discuss the nucleation mechanism and process of hybrid core–shell poly(alkyltrialkoxysiloxane) latex particles’ formation.
Probing nanoscale graphene–liquid interfacial interactions via ultrasonic force spectroscopy
Authors: Robinson Benjamin J. , Kolosov Oleg V.
Published: July 2014

The study of interfacial forces in graphene–air and graphene–liquid environments with nanoscale resolution by experimental and theoretical development of novel ultrasonic force spectroscopy (UFS).
The use of atomic layer deposition in advanced nanopatterning
Authors: Mackus A. J. M. , Bol A. A. , Kessels W. M. M.
Published: July 2014

This article reviews the patterning of films deposited by atomic layer deposition (ALD), as well as the use of ALD as an enabling technology in advanced nanopatterning schemes.
Vacancy patterning and patterning vacancies: controlled self-assembly of fullerenes on metal surfaces
Authors: Kaiser Alexander , Viñes Francesc , Illas Francesc , Ritter Marcel , Hagelberg Frank , Probst Michael
Published: July 2014

A density functional theory study accounting for van der Waals interactions reveals the potential of either using metal surface vacancies as anchor points for the design of 2D patterns of adsorbate molecules or vice versa using adsorbate monolayers to design vacancy patterns.
Anion dependent self-assembly of 56-metal Cd–Ln nanoclusters with enhanced near-infrared luminescence properties
Authors: Yang Xiaoping , Schipper Desmond , Zhang Lijie , Yang Keqin , Huang Shaoming , Jiang Jijun , Su Chengyong , Jones Richard A.
Published: July 2014

Two luminescent 56-metal Cd–Ln nanoclusters with unusual nano-double-drum-like structures were prepared using a flexible Schiff base ligand which contains two aryl-Br groups.
A cancer-targeted drug delivery system developed with gold nanoparticle mediated DNA–doxorubicin conjugates
Authors: Du Yu Qing , Yang Xiao Xi , Li Wen Long , Wang Jian , Huang Cheng Zhi
Published: July 2014

A targeted drug delivery system based on AuNPs and DNA was developed to treat neuroblastoma cancer. This system exhibits excellent specificity in delivering and releasing doxorubicin, and has great prospects in clinical applications.
Sandwich-like graphene nanosheets decorated with superparamagnetic CoFe2O4 nanocrystals and their application as an enhanced electromagnetic wave absorber
Authors: Li Xinghua , Feng Juan , Zhu Hao , Qu Chunhao , Bai Jintao , Zheng Xinliang
Published: July 2014

Sandwich-structured CoFe2O4/graphene hybrids are fabricated through a facile one-pot polyol route, and the electromagnetic wave absorption properties are investigated.
Nucleophilic radiofluorination at room temperature via aziridinium intermediates
Authors: Médoc M. , Sobrio F.
Published: July 2014

2-Fluoroamines were synthesized at RT from alcohols with different sources of nucleophilic [18F]- or [19F]-fluoride.
Formation and rupture of Ca2+ induced pectin biopolymer gels
Authors: Basak Rajib , Bandyopadhyay Ranjini
Published: July 2014

Flocs of pectin biomacromolecules, whose sizes and size polydispersities increase with added salt, aggregate to form a gel that lies in the strong link regime.
Photo-directed growth of Au nanowires on ZnO arrays for enhancing photoelectrochemical performances
Authors: Wang Teng , Jin Bingjun , Jiao Zhengbo , Lu Gongxuan , Ye Jinhua , Bi Yingpu
Published: July 2014

Herein, we demonstrate that ZnO nanowire arrays could be rationally connected with each other by thin Au nanowires to construct a novel cross-linked hetero-structure by a simple photo-directed growth strategy, which exhibit much higher visible light photocurrent density than traditional Au nanoparticle/ZnO nanowire heterostructures.
A facile preparation of ZnGa2O4photonic crystals with enhanced light absorption and photocatalytic activity
Authors: Li Xiaofang , Zhang Xiaoyun , Zheng Xiuzhen , Shao Yu , He Miao , Wang Peng , Fu Xianzhi , Li Danzhen
Published: July 2014

A facile method to prepare ZnGa2O4photonic crystals with enhanced electronic band absorption and photocatalytic activity.
Open-circuit voltage shifted by the bending effect for flexible organic solar cells
Authors: Chou Wei-Yang , Yen Chia-Te , Wu Fu-Chiao , Cheng Horng-Long , Liu Shyh-Jiun , Tang Fu-Ching
Published: July 2014

A bending effect induced open-circuit voltage shift in flexible OSCs plays important roles in driving the loading devices on flexible circuits.
Iron oxide nanostructures as highly efficient heterogeneous catalysts for mesoscopic photovoltaics
Authors: Wang Liang , Shi Yantao , Zhang Hong , Bai Xiaogong , Wang Yanxiang , Ma Tingli
Published: July 2014

Fe3O4 with hierarchical structures was successfully synthesized and introduced into dye-sensitized solar cells as the counter electrode.
In vitro investigation of the mutagenic potential of Aloe vera extracts
Authors: Guo Xiaoqing , Zhang Suhui , Dial Stacey L. , Boudreau Mary D. , Xia Qingsu , Fu Peter P. , Levy Dan D. , Moore Martha M. , Mei Nan
Published: July 2014

Both theAloe verawhole leaf extract and decolorized whole leaf extract were mutagenic in cultured cells with different genetic damage.
Selective induction and subcellular distribution of ACONITASE 3 reveal the importance of cytosolic citrate metabolism during lipid mobilization in Arabidopsis
Authors: Hooks Mark A. , Allwood J. William , Harrison Joanna K. D. , Kopka Joachim , Erban Alexander , Goodacre Royston , Balk Janneke
Published: July 2014

Arabidopsis thaliana has three genes that encode distinct aconitases (ACO), but little is known about the function of each isoenzyme during plant development. In newly emerged seedlings of Arabidopsis, transcript and protein levels for ACO3 were selectively induced to yield more than 80% of total aconitase activity. Characterization of knockout mutants for each of the three ACOs suggests a major role for only ACO3 in citrate metabolism. The aco3 mutant showed delayed early seedling growth, altered assimilation of [14C]acetate feeding and elevated citrate levels, which were nearly 4-fold greater than in wild-type, aco1 or aco2. However, both ACO1 and ACO2 are active in seedlings as shown by inhibition of aco3 growth by the toxin monofluoroacetate, and altered [14C]acetate assimilation and metabolite levels in aco1 and aco2. Relative levels of fumarate and malate differed between aco2 and aco3, indicating metabolically isolated pools of these metabolites in seedlings. Our inability to enrich ACO protein through mitochondria isolation, and the reduced cytosolic ACO activity of the iron–sulfur centre assembly mutant atm3-1, indicated a cytosolic localization of ACO3 in 3-day-old seedlings. Subsequently, we determined that more than 90% of ACO3 was cytosolic. We conclude that ACO3 is cytosolic in young seedlings and functions in citrate catabolism consistent with the operation of the classic glyoxylate and not direct catabolism of citrate within mitochondria.
Novel potential targets for prevention of arterial restenosis: insights from the pre-clinical research
Authors: Forte Amalia , Rinaldi Barbara , Berrino Liberato , Rossi Francesco , Galderisi Umberto , Cipollaro Marilena
Published: July 2014

Restenosis is the pathophysiological process occurring in 10–15% of patients submitted to revascularization procedures of coronary, carotid and peripheral arteries. It can be considered as an excessive healing reaction of the vascular wall subjected to arterial/venous bypass graft interposition, endarterectomy or angioplasty. The advent of bare metal stents, drug-eluting stents and of the more recent drug-eluting balloons, have significantly reduced, but not eliminated, the incidence of restenosis, which remains a clinically relevant problem. Biomedical research in pre-clinical animal models of (re)stenosis, despite its limitations, has contributed enormously to the identification of processes involved in restenosis progression, going well beyond the initial dogma of a primarily proliferative disease. Although the main molecular and cellular mechanisms underlying restenosis have been well described, new signalling molecules and cell types controlling the progress of restenosis are continuously being discovered. In particular, microRNAs and vascular progenitor cells have recently been shown to play a key role in this pathophysiological process. In addition, the advanced highly sensitive high-throughput analyses of molecular alterations at the transcriptome, proteome and metabolome levels occurring in injured vessels in animal models of disease and in human specimens serve as a basis to identify novel potential therapeutic targets for restenosis. Molecular analyses are also contributing to the identification of reliable circulating biomarkers predictive of post-interventional restenosis in patients, which could be potentially helpful in the establishment of an early diagnosis and therapy. The present review summarizes the most recent and promising therapeutic strategies identified in experimental models of (re)stenosis and potentially translatable to patients subjected to revascularization procedures.
One‐step model extraction method for direct learning digital predistortion
Authors: Yang Guang , Wang Haoyu , Li Lingli , Liu Falin
Published: July 2014

A one‐step model extraction method is proposed for direct learning (DL) digital predistortion (DPD) system. The expected predistortion signal of the training sequence is first derived by iterative injection of the baseband distortion components, which enables one‐step model extraction of the DPD model by least squares estimation afterwards. Compared with the conventional model extraction method for DL DPD, the proposed method yields comparable linearisation performance but has much lower computational complexity.
Fast decoding for RaptorQ codes using matrix dimensionality reduction
Authors: Guo Xiao , Zhang Geng‐Xin , Tian Chang , Zhang Lei , Zhao Weng‐Dong
Published: July 2014

A very fast decoding algorithm using matrix dimensionality reduction for RaptorQ codes is proposed. The algorithm exploits a pre‐calculated inverse matrix to achieve dimensionality reduction for the received code constraint matrix. As a result, the decoding complexity is decreased significantly, whereas the failure‐overhead curve is still identical to that of conventional approaches. Simulations show that the decoding speed of the proposed algorithm can be as fast as 17.5 times the state‐of‐the‐art algorithm when the erasure probability is relatively low.
Magnetic current formulation for periodically loaded slots
Authors: Mias C. , Freni A.
Published: July 2014

A novel adaptation of the Wait‐Hill formulation is proposed for the analysis of plane wave scattering from periodically loaded orthogonal slots. For the case of vertical slots loaded with infinitesimal lumped elements, the formulation leads to a novel exact analytical expression for the fundamental harmonic current amplitude. In addition, the formulation is shown to provide insight into lumped‐element loaded slot miniaturised frequency selective surfaces.
Dual‐band bandpass filter with wide upper stopband using quad‐mode stepped impedance stub‐loaded resonator
Authors: Lin Lei , Sun Shou‐Jia , Wu Bian , Liang Chang‐Hong
Published: July 2014

A novel quad‐mode stepped impedance stub‐loaded resonator is presented. The even–odd‐mode method is applied twice to analyse the modal resonance characteristics due to its symmetry. All the four modes' equivalent circuits are quarter‐wavelength stepped impedance resonators, so the proposed resonator has a compact size and higher harmonic frequencies. Stub‐to‐stub coupling is introduced to split two identical modes and produce two transmission zeros. A dual‐band bandpass filter operating at 1.5 and 2.4 GHz is designed using the proposed resonator. The centre frequency and bandwidth of each passband can be controlled by tuning the corresponding physical dimensions, and a wide upper stopband is achieved. Finally, the designed filter was fabricated and measured, and the measured results have good agreement with the simulated ones.
Iterative receiver with soft‐input‐based‐channel estimation for orthogonal frequency division multiplexing‐interleave division multiple access systems
Authors: Oyerinde Olutayo O. , Mneney Stanley H.
Published: July 2014

This article presents two sets of channel estimation methods that employ soft input from the decoder to enhance channel estimation process for orthogonal frequency division multiplexing ‐interleave division multiple access (OFDM‐IDMA) system. The first channel estimation scheme exploits both time and frequency domains for channel estimation and prediction. The estimator exploits turbo principle while using iterative based sequential linear minimum mean square error (ISLMMSE) for channel transfer function (CTF) estimation, and regularised variable step size normalised least mean square (ℓ1‐VSSNLMS) algorithm for channel impulse response (CIR) prediction. The channel estimation scheme exchanges information with the Multi‐User Detector (MUD), and also employs soft information feedback from the decoder for the enhancement of channel estimation. The second iterative channel estimation scheme, in time domain, is based on regularised noise power estimate‐based variable forgetting factor recursive least square (ℓ1‐NPEVFF‐RLS)‐based CIR estimator. The performances of the proposed estimators are documented through computer simulation. Their comparative performances with other schemes in the literature are presented in this article. From the simulation results, the two proposed channel estimators exhibit better performance in comparison with other schemes in the literature, but with higher computational complexities. However, of the two proposed methods, the ℓ1‐NPEVFF‐RLS‐based CIR estimator that exhibits almost the same performance as the combined ISLMMSE‐based CTF estimator and ℓ1‐VSSNLMS‐based predictor exhibits lower computational complexity.
Multi‐loop PI/PID controllers design for disturbance rejection based on non‐parametric effective model and non‐convex optimisation
Authors: Jin Qibing , Liu Qie
Published: July 2014

In this study, the authors address the design of the multi‐loop controllers for multi‐input and multi‐output (MIMO) processes for disturbance rejection. Three types of disturbance rejection are analysed, and they demonstrate that those disturbance responses are directly related to the integral terms of the controllers. A concept of non‐parametric effective model is introduced here to decompose a MIMO control system into several equivalent single‐input and single‐output control systems. Based on the effective model in each loop, a non‐convex optimisation problem is established to obtain the optimal controller parameters with certain robustness indices. Considering the drawbacks of using random search algorithm, they develop a numerical algorithm to solve this non‐convex optimisation problem. Simulation studies demonstrate that the proposed method improves the disturbance rejection compared with other decentralised controllers.
Stabilisation of a class of two‐dimensional nonlinear systems with intermittent measurements
Authors: Xuhui Bu , Hongqi Wang , Zhongsheng Hou , Wei Qian
Published: July 2014

This study is concerned with the problem of stabilisation for a class of two‐dimensional (2D) nonlinear systems with intermittent measurements and sector nonlinearities. The intermittent measurement is modelled by a stochastic variable satisfying the Bernoulli random binary distribution. Our attention is focused on the design of a state feedback controller for such 2D stochastic system described by the Roesser model, such that the closed‐loop system is mean‐square asymptotically stable. A sufficient condition is established by means of linear matrix inequalities technique, and formulae can be given for the control law design. The result is also extended to more general cases where the system matrices contain uncertain parameters. Numerical examples are also given to illustrate the effectiveness of proposed approach.
Robust extended Kalman filter for attitude estimation with multiplicative noises and unknown external disturbances
Authors: Hua‐ming Qian , Wei Huang , Lin‐chen Qian , Chen Shen
Published: July 2014

This study is concerned with the robust extended Kalman filtering problem for non‐linear attitude estimation systems with multiplicative noises and unknown external disturbances. The multiplicative noises are modelled by random variables with bounded variance. The unknown external disturbances are described to lie in bounded set. The objective of the addressed attitude estimation problem is to design a filter such that, in the presence of both the multiplicative noises and unknown external disturbances, an optimised upper bound on the state estimation error variance can be guaranteed. Thus, a robust extended Kalman filter (REKF) is presented for attitude estimation with multiplicative noises and unknown external disturbances. Compared with the traditional extended Kalman filter in attitude estimation, the proposed algorithm takes into consideration the effects of multiplicative noises and unknown external disturbances. Moreover, the stability of the proposed REKF can be proved under certain conditions by utilising the stochastic stability theory. Finally, the simulation results demonstrate the effectiveness of the proposed REKF.
Sampling‐based learning control of quantum systems via path planning
Authors: Chen Chunlin , Long Ruixing , Qi Bo , Dong Daoyi
Published: July 2014

Robust control design is a central problem for quantum systems in practical implementation and applications. In this study, the authors present a systematic methodology of sampling‐based learning control via path planning for state transfer of quantum systems with uncertainties and bounded controls. The authors formulate the control problem of a quantum system with bounded uncertainties as the problem of steering this system to a target state with bounded controls via an optimised evolution path to achieve a satisfactory level of fidelity. To find the optimised path (controls), the authors present a combined design method of sampling‐based learning control and path planning. The numerical results on an example of a four‐level quantum system show the effectiveness of the proposed learning control design method. The method provides a useful design approach for learning control of quantum systems with uncertainties.
Enhancement of electric arc furnace reactive power compensation using Grey–Markov prediction method
Authors: Samet Haidar , Mojallal Aslan
Published: July 2014

The time varying nature of electric arc furnace (EAF) gives rise to voltage fluctuations, which produces the effect known as flicker. Employing reactive power compensation devices such as static VAr compensator (SVC) is one of the main approaches to mitigate this phenomenon. By utilising prediction methods to forecast EAFs reactive power consumption for a half‐cycle ahead, performance of SVC can be enhanced substantially. This study proposes a rolling Grey model and a Grey–Markov method to predict the actual reactive power of Mobarakeh Steel Company, Isfahan/Iran. To investigate the efficiency of the proposed methods the results are compared with the results of EAFs reactive power compensation when no prediction method is employed. Furthermore, autoregressive moving average (ARMA) models with updating coefficients, which are studied in the literature are used to predict EAF reactive power. Various methods for updating ARMA coefficients including normalised least mean square, recursive least square method and an online genetic algorithm are used. By comparing the indices which are defined using the concept of flicker frequency and power spectral density, the superiority of Grey–Markov and rolling Grey model over the aforementioned prediction methods is investigated.
Characterisation of gas turbine dynamics during frequency excursions in power networks
Authors: Meegahapola Lasantha
Published: July 2014

Gas turbines inherently depict unique frequency response characteristics compared with other conventional synchronous generation technologies as their active power output is not entirely determined by the governor response during frequency deviations of the power network. Thus, gas turbine dynamics significantly influence on system stability during frequency events in power networks. Power system and power plant operators require improved understanding of the gas turbine characteristics during various frequency events in order to mitigate adverse impact on power system. Therefore a comparative analysis has been performed between combined‐cycle gas turbines (CCGTs) and open‐cycle gas turbines (OCGTs) in order to characterise the dynamic behaviour considering different types of frequency events in power networks. Study has shown that CCGTs result in significant frequency variations in power networks in comparison with OCGTs because of the temperature control action performed by the fast acting inlet guide vanes at the combustor. In particular, they are susceptible to lean blowout during large frequency increase events such as short‐circuit faults in power networks. Furthermore, a case study was developed based on the New England‐39 bus system in order to illustrate the impact of gas turbine dynamics on network frequency during short‐circuit events in power networks.
Transmission expansion planning using AC‐based differential evolution algorithm
Authors: Alhamrouni Ibrahim , Khairuddin Azhar , Ferdavani Ali Khorasani , Salem Mohamed
Published: July 2014

The rapid growth of the transmission networks has brought more uncertainties and new requirements in the transmission expansion planning (TEP) to the planners. The existing methods of solving TEP problem have a drawback since the DC load flow and the relaxed load flow models have been utilized to solve TEP problem. In this work, the TEP problem is solved based on mixed integer nonlinear non‐convex programming model. A meta‐heuristic algorithm by the means of differential evolution algorithm (DEA) is employed as an optimisation tool. An AC load flow model is used in solving the TEP problem, where accurate and realistic results can be obtained. Furthermore, the work considers the constraints checking and system violation such as real and power generation limits, possible number of lines added and bus voltage limits. The proposed technique is tested on Garver's 6 bus system and IEEE 24 bus system and has shown high capability in considering the active and reactive power in the same manner and solving the TEP problem. The method produced improved results for the test systems. In terms of minimising the cost and the solution quality, the proposed method obtained good and challenging results comparing to the previous works.
Reliability analysis of phasor measurement unit incorporating hardware and software interaction failures
Authors: Roy Diptendu Sinha , Murthy Cherukuri , Mohanta Dusmanta Kumar
Published: July 2014

As the electrical power system has increased in its geographical sprawl, adequate measures for reliability analysis for the wide area measurement system (WAMS) and phasor measurement units (PMUs) have become necessary. However, existing PMU reliability models are constrained by the assumption that PMU failures may be encountered either because of hardware failures or because of software failures only. Most modem safety critical systems, like the PMU are characterised by close proximity of hardware and software operations which leads to correlated failures. This is referred to as hardware–software interaction failure and is disregarded by contemporary PMU reliability models. In this paper, a modelling framework has been developed using Markov process that captures hardware–software interaction failures, apart from the hardware specific and software specific failures, and presents a Markov model‐based unified PMU reliability model. This paper also offers a novel Monte Carlo simulation (MCS) technique to estimate PMU failure data to account for scanty PMU failure data from field installations. The novel algorithms for MCS based PMU failure estimation are expounded along with detailed methodologies for fitting the simulated failure data to the unified reliability model. The results presented herein demonstrate the improved accuracy of the proposed method.