bluuebunny/crossref_metadata_2025 huggingface dataset:
Raptor abundance and northern bobwhite survival and habitat use
Authors: Turner Joshua W. , Hernández Fidel , Boal Clint W. , Ballard Bart M. , Bryant Fred C. , Wester David B.
Published: September 2014

Predation risk has a profound influence on prey behavior and habitat use. The Rio Grande Plains ecoregion of Texas, USA, provides a unique opportunity to investigate changes in prey behavior because the ecoregion experiences a high influx of raptors every year during autumn migration. We used an 8‐year data set (2000–2008) of radiocollared northern bobwhites (Colinus virginianus) and raptor abundance to test the hypothesis that bobwhites responded to increased raptor abundance via changes in woody‐cover use at the home‐range scale. Bobwhite survival was negatively correlated with raptor abundance, with red‐tailed hawks (Buteo jamaicensis), and northern harriers (Circus cyaneus) accounting for 51% of the variability in bobwhite survival (P < 0.010). However, we documented no change in the amount of woody cover used by bobwhites in their home range between the raptor migration (6.6% ± 0.5%; n = 73 bobwhites) and non‐migration periods (7.1% ± 0.4%; n = 105 bobwhites; P = 0.490). In addition, bobwhites that survived the raptor migration period used similar amounts of woody cover within their home range (6.3% ± 0.6%, n = 58 bobwhites) compared with those dying during the migration period (6.8% ± 0.4%, n = 100 bobwhites; P = 0.530). Our data suggest that bobwhites do not alter their use of woody cover at the home‐range scale in response to increasing raptor abundance, but this does not preclude increased use of woody cover at the point‐of‐use scale. © 2014 The Wildlife Society.
Identification of appropriate reference genes for human mesenchymal stem cell analysis by quantitative real-time PCR
Authors: Li Xiuying , Yang Qiwei , Bai Jinping , Xuan Yali , Wang Yimin
Published: September 2014

Normalization to a reference gene is the method of choice for quantitative reverse transcription-PCR (RT-qPCR) analysis. The stability of reference genes is critical for accurate experimental results and conclusions. We have evaluated the expression stability of eight commonly used reference genes found in four different human mesenchymal stem cells (MSC). Using geNorm, NormFinder and BestKeeper algorithms, we show that beta-2-microglobulin and peptidyl-prolylisomerase A were the optimal reference genes for normalizing RT-qPCR data obtained from MSC, whereas the TATA box binding protein was not suitable due to its extensive variability in expression. Our findings emphasize the significance of validating reference genes for qPCR analyses. We offer a short list of reference genes to use for normalization and recommend some commercially-available software programs as a rapid approach to validate reference genes. We also demonstrate that the two reference genes, β-actin and glyceraldehyde-3-phosphate dehydrogenase, are frequently used are not always successful in many cases.
Segregation in dense sheared flows: gravity, temperature gradients, and stress partitioning
Authors: Hill K. M. , Tan Danielle S.
Published: September 2014

It is well-known that in a dense, gravity-driven flow, large particles typically rise to the top relative to smaller equal-density particles. In dense flows, this has historically been attributed to gravity alone. However, recently kinetic stress gradients have been shown to segregate large particles to regions with higher granular temperature, in contrast to sparse energetic granular mixtures where the large particles segregate to regions with lower granular temperature. We present a segregation theory for dense gravity-driven granular flows that explicitly accounts for the effects of both gravity and kinetic stress gradients involving a separate partitioning of contact and kinetic stresses among the mixture constituents. We use discrete-element-method (DEM) simulations of different-sized particles in a rotated drum to validate the model and determine diffusion, drag, and stress partition coefficients. The model and simulations together indicate, surprisingly, that gravity-driven kinetic sieving is not active in these flows. Rather, a gradient in kinetic stress is the key segregation driving mechanism, while gravity plays primarily an implicit role through the kinetic stress gradients. Finally, we demonstrate that this framework captures the experimentally observed segregation reversal of larger particles downward in particle mixtures where the larger particles are sufficiently denser than their smaller counterparts.
Pressure Hessian and viscous contributions to velocity gradient statistics based on Gaussian random fields
Authors: Wilczek Michael , Meneveau Charles
Published: September 2014

Understanding the non-local pressure contributions and viscous effects on the small-scale statistics remains one of the central challenges in the study of homogeneous isotropic turbulence. Here we address this issue by studying the impact of the pressure Hessian as well as viscous diffusion on the statistics of the velocity gradient tensor in the framework of an exact statistical evolution equation. This evolution equation shares similarities with earlier phenomenological models for the Lagrangian velocity gradient tensor evolution, yet constitutes the starting point for a systematic study of the unclosed pressure Hessian and viscous diffusion terms. Based on the assumption of incompressible Gaussian velocity fields, closed expressions are obtained as the results of an evaluation of the characteristic functionals. The benefits and shortcomings of this Gaussian closure are discussed, and a generalization is proposed based on results from direct numerical simulations. This enhanced Gaussian closure yields, for example, insights on how the pressure Hessian prevents the finite-time singularity induced by the local self-amplification and how its interaction with viscous effects leads to the characteristic strain skewness phenomenon.
The effectiveness of an air curtain in the doorway of a ventilated building
Authors: Frank D. , Linden P. F.
Published: September 2014

Air curtains are used to reduce the heat and mass exchange across open doorways. Their sealing ability is assessed in terms of the effectiveness $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}E$, the fraction of the exchange flow prevented by the air curtain compared to an unobstructed open door. Previous work has studied air-curtain effectiveness when the doorway is the only means of ventilating a space. In this paper, we examine the effects of additional displacement ventilation on the dynamics of the air curtain and the resulting changes in its effectiveness. The main controlling parameter is the deflection modulus $D_{m}$, which is the ratio between the momentum flux of the air curtain and the transverse forces due to the displacement ventilation. For a relatively warm interior, we find that, for small values of $D_{m}$, the air curtain is drawn inside the space by the ventilation flow. For large values of $D_{m}$, the flow through the doorway is controlled by the air curtain. A smooth transition occurs between these two regimes, and we estimate the $D_{m}$ value for the onset of this transition. Our model provides a quantitative prediction of $E(D_{m})$ in the ventilation-driven regime, and gives a qualitative description of the other two regimes. Laboratory experiments were conducted to test the proposed model. The experimental data were compared to theoretical predictions, and good agreement was found.
Fluid flow analysis of a shark-inspired microstructure
Authors: Martin Samuel , Bhushan Bharat
Published: September 2014

The scales of fast-swimming sharks contain riblet structures with microgrooves, aligned in the direction of fluid flow, that result in water moving efficiently over the surface. In previous studies, these riblet structures have shown a drag reduction of up to 10 % when compared with a smooth, flat surface. These studies have suggested two prevalent drag-reduction mechanisms which involve the effect of vortices and turbulence fluctuations. To further explore relevant mechanisms and study the effect of riblet geometry and flow properties on drag, vortices and turbulence fluctuations, various shark-skin-inspired riblet structures were created using computational models in which velocity, viscosity, spacing, height and thickness parameters were independently modified. A relevant mechanism of drag reduction is discussed to relate riblet parameters and flow properties to drag change and vortex size. Modelling information will lead to a better understanding of riblets and allow for optimum drag-reducing designs for applications in marine, medical and industrial fields.
Evolution of the velocity-gradient tensor in a spatially developing turbulent flow
Authors: Gomes-Fernandes R. , Ganapathisubramani B. , Vassilicos J. C.
Published: September 2014

An experimental study of turbulence generated by a low-blockage space-filling fractal square grid was performed using cinematographic stereoscopic particle image velocimetry in a water tunnel. All fluctuating velocity gradients were measured and their statistics were computed at three different stations along the streamwise direction downstream of the grid: in the production region, at the location of peak turbulence intensity and in the non-equilibrium decay region. The usual signatures of these statistics are only found in the decay region, where a well-defined$\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}2/3$power-law dependence of the second-order structure function on two-point distance is also present. However, this$2/3$exponent is well defined over a wide range of scales even at the peak location, where the statistics of the fluctuating velocity-gradient tensor are very unusual. There, as at the production region station, the$Q\text {--}R$teardrop shape is not yet fully developed, vortex stretching only slightly dominates over compression and they both fluctuate very widely, reaching very high low-probability values. In these two stations, there is also only marginal preference between sheet-like and tube-like velocity-gradient structures as seen by the sign of the second eigenvalue of the strain-rate tensor. Yet, there are subregions of the flow in the production region where the$2/3$exponent is present and where the$Q\text {--}R$teardrop shape is as undeveloped as for the entire data set at this station.
A run-time representation of scheme record types
Authors: KEEP ANDREW W. , DYBVIG R. KENT
Published: September 2014

The Revised6Report on the Algorithmic Language Scheme added a mechanism to the Scheme programming language for creating new record types procedurally. While many programming languages support user defined, structured data types, these are usually handled syntactically, so that the compiler can make choices at compile time about the memory layout of these data types. The procedural record types in Scheme, however, can be constructed at run time, making the efficient run-time representation of record types important to ensure good run-time performance. The run-time representation used in our implementation provides an extended model for record types allowing record types to represent foreign scalar data types, e.g., machine word integers, and allows the base record type to be extended to create non-R6RS record-type systems. This article describes our run-time representation for record types, how the garbage collector handles foreign scalar data types, and includes extended record type systems both for an object-oriented programming model and a representation of foreign structured data types.
Particle Verbs in the Surinamese Creoles
Authors: Borges Robert
Published: September 2014

This paper shows that Dutch verb-particle constructions have been transferred into the Surinamese creole languages as a result of pervasive multilingualism and intensive contact. Particle-verb structures are, at most, marginal in the native grammar of Surinamese creoles. However, recent data show that verb-particle constructions of the Dutch sort are becoming productive and are used with some homogeneity in the creole language context.
A robust SNP barcode for typing Mycobacterium tuberculosis complex strains
Authors: Coll Francesc , McNerney Ruth , Guerra-Assunção José Afonso , Glynn Judith R. , Perdigão João , Viveiros Miguel , Portugal Isabel , Pain Arnab , Martin Nigel , Clark Taane G.
Published: September 2014

Strain-specific genomic diversity in the Mycobacterium tuberculosis complex (MTBC) is an important factor in pathogenesis that may affect virulence, transmissibility, host response and emergence of drug resistance. Several systems have been proposed to classify MTBC strains into distinct lineages and families. Here, we investigate single-nucleotide polymorphisms (SNPs) as robust (stable) markers of genetic variation for phylogenetic analysis. We identify ~92k SNP across a global collection of 1,601 genomes. The SNP-based phylogeny is consistent with the gold-standard regions of difference (RD) classification system. Of the ~7k strain-specific SNPs identified, 62 markers are proposed to discriminate known circulating strains. This SNP-based barcode is the first to cover all main lineages, and classifies a greater number of sublineages than current alternatives. It may be used to classify clinical isolates to evaluate tools to control the disease, including therapeutics and vaccines whose effectiveness may vary by strain type.
Effective connectivity during animacy perception – dynamic causal modelling of Human Connectome Project data
Authors: Hillebrandt Hauke , Friston Karl J. , Blakemore Sarah-Jayne
Published: September 2014

Biological agents are the most complex systems humans have to model and predict. In predictive coding, high-level cortical areas inform sensory cortex about incoming sensory signals, a comparison between the predicted and actual sensory feedback is made and information about unpredicted sensory information is passed forward to higher-level areas. Predictions about animate motion – relative to inanimate motion – should result in prediction error and increase signal passing from lower level sensory area MT+/V5, which is responsive to all motion, to higher-order posterior superior temporal sulcus (pSTS), which is selectively activated by animate motion. We tested this hypothesis by investigating effective connectivity in a large-scale fMRI dataset from the Human Connectome Project. 132 participants viewed animations of triangles that were designed to move in a way that appeared animate (moving intentionally), or inanimate (moving in a mechanical way). We found that forward connectivity from V5 to the pSTS increased and inhibitory self-connection in the pSTS decreased, when viewing intentional motion versus inanimate motion. These prediction errors associated with animate motion may be the cause for increased attention to animate stimuli found in previous studies.
Detection of Volatile Organic Compounds by Weight-Detectable Sensors coated with Metal-Organic Frameworks
Authors: Yamagiwa Hiroki , Sato Seiko , Fukawa Tadashi , Ikehara Tsuyoshi , Maeda Ryutaro , Mihara Takashi , Kimura Mutsumi
Published: September 2014

Detection of volatile organic compounds (VOCs) using weight-detectable quartz microbalance and silicon-based microcantilever sensors coated with crystalline metal-organic framework (MOF) thin films is described in this paper. The thin films of two MOFs were grown from COOH-terminated self-assembled monolayers onto the gold electrodes of sensor platforms. The MOF layers worked as the effective concentrators of VOC gases and the adsorption/desorption processes of the VOCs could be monitored by the frequency changes of weight-detectable sensors. Moreover, the MOF layers provided VOC sensing selectivity to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs.
Surfactant-free nanoparticle–DNA complexes with ultrahigh stability against salt for environmental and biological sensing
Authors: Heo Jun Hyuk , Cho Hui Hun , Lee Jung Heon
Published: September 2014

A AuNP–DNA complex highly stable in extremely high ionic strength media, such as seawater, was obtained by inserting a few thymine bases into the DNA strands.
Elastomeric nanocomposite scaffolds made from poly(glycerol sebacate) chemically crosslinked with carbon nanotubes
Authors: Gaharwar Akhilesh K. , Patel Alpesh , Dolatshahi-Pirouz Alireza , Zhang Hongbin , Rangarajan Kaushik , Iviglia Giorgio , Shin Su-Ryon , Hussain Mohammad Asif , Khademhosseini Ali
Published: September 2014

We report fabrication of stiff, elastomeric nanocomposites by covalently crosslinking poly(glycerol sebacate) (PGS) and CNTs for biomedical applications.
A turn-on fluorogenic Zn(ii) chemoprobe based on a terpyridine derivative with aggregation-induced emission (AIE) effects through nanofiber aggregation into spherical aggregates
Authors: Jung Sung Ho , Kwon Ki-Young , Jung Jong Hwa
Published: September 2014

The self-assembly of the terpyridine-based ligand exhibited strong emission in the presence of Zn2+ due to the formation of coordination bonds between the terpyridine moieties and the Zn2+ by the aggregation-induced emission effect.
Isolation of stable non cyclic 1,2-disulfoxides. Revisiting the thermolysis of S-aryl sulfinimines
Authors: Souto José A. , Lewis Willian , Stockman Robert A.
Published: September 2014

The thermolysis of S-aryl sulfinimines is shown to generate 1,2-disulfoxides and disulfides via initial Cope elimination, dimerisation of the produced sulfenic acid to a thiosulfinate, and subsequent disproportionation of the thiosulfinate.
Synthesis of clickable amphiphilic polysaccharides as nanoscopic assemblies
Authors: Fu Liye , Li Lingyao , Wang Jun , Knickelbein Kyle , Zhang Lin , Milligan Ian , Xu Yi , O'Hara Kylie , Bitterman Lindsay , Du Wenjun
Published: September 2014

Amphiphilic polysaccharides were synthesized to construct carbohydrate-based nanoparticles, which exhibited no toxicity to cells.
Proof-of-principle direct double cyclisation of a linear C15-precursor to a dibrominated bicyclic medium-ring ether relevant toLaurenciaspecies
Authors: Braddock D. Christopher , Sbircea Dan-Tiberiu
Published: September 2014

Bicyclic medium ring ethers of relevance toLaurenciaspecies have been obtained by direct double brominative cyclisation of an acyclic precursor.
Fluorescence visualization of the molecular assembly processes during solvent evaporation via aggregation-induced emission in a cyanostilbene derivative
Authors: Ito Fuyuki , Fujimori Jun-ichi
Published: September 2014

We applied AIEE to the visualization of crystal formation processes. We found that J-aggregates act as precursors for crystal nuclei, and that the growth from J-aggregates to crystal nuclei is the rate-determining step in the nucleation process.
Hollow structured and flower-like C@MnCo2O4composite for high electrochemical performance in a supercapacitor
Authors: Li Lei , He Fei , Gai Shili , Zhang Shenghuan , Gao Peng , Zhang Milin , Chen Yujin , Yang Piaoping
Published: September 2014

A flower-like C@MnCo2O4composite with a hollow structure was synthesized through a hydrothermal method followed by a calcination process, which shows enhanced rate capability and an excellent cycling stability of 95.9% retention after 1000 cycles.
Anion-templated assembly of three indium–organic frameworks with diverse topologies
Authors: Wang Jing , Luo Jiahuan , Zhi Bo , Li Guanghua , Huo Qisheng , Liu Yunling
Published: September 2014

Three novel In-MOFs with ung, crb and cbo networks based on the H2bpydc ligand have been prepared under solvothermal conditions. Structural analyses reveal that these three compounds possess monomeric indium inorganic building units and they are obtained using different anion templates such as NO3−, HCOO− and Cl−.
Hydrogen bond architecture in crystal structures of N-alkylated hydrophobic amino acids
Authors: Görbitz C. H. , Leirvåg A. B. , Jacobsen Ø.
Published: September 2014

The crystal structures of N-alkylated hydrophobic amino acids, including five new compounds, show robust and characteristic hydrogen bond patterns.
Car–Parrinello and path integral molecular dynamics study of the intramolecular hydrogen bonds in the crystals of benzoylacetone and dideuterobenzoylacetone
Authors: Durlak Piotr , Latajka Zdzisław
Published: September 2014

The dynamics of the intramolecular short hydrogen bond in the molecular crystal of benzoylacetone and its deuterated analogue are investigated usingab initiomolecular dynamics simulations.
A theoretical study of three gas-phase reactions involving the production or loss of methane cations
Authors: Baptista Leonardo , da Silveira Enio F.
Published: September 2014

Three reactions paths involving methane cation were studied by multiconfigurational methods and the rate coefficients and Arrhenius parameters were obtained.
Conducting behavior of chalcopyrite-type CuGaS2 crystals under visible light
Authors: Cholula-Díaz Jorge L. , Barzola-Quiquia José , Kranert Christian , Michalsky Tom , Esquinazi Pablo , Grundmann Marius , Krautscheid Harald
Published: September 2014

The dynamic electrical properties of chalcopyrite-type CuGaS2 crystals investigated by transient alternating current photoresistance measurements reveal a negative or positive photoresistance effect depending on the a.c. frequency.
A DFT + U computational study on stoichiometric and oxygen deficient M–CeO2 systems (M = Pd1, Rh1, Rh10, Pd10 and Rh4Pd6)
Authors: Choi YongMan , Scott M. , Söhnel T. , Idriss Hicham
Published: September 2014

Molecular and dissociative adsorption processes of ethanol on stoichiometric and O-defected CeO2(111) surfaces alone as well as in the presence of one metal atom (Pd or Rh) are studied using spin-polarized density functional theory (DFT) with the GGA + U method (Ueff = 5.0 eV).
Infrared detection of (H2O)20 isomers of exceptional stability: a drop-like and a face-sharing pentagonal prism cluster
Authors: Pradzynski Christoph C. , Dierking Christoph W. , Zurheide Florian , Forck Richard M. , Buck Udo , Zeuch Thomas , Xantheas Sotiris S.
Published: September 2014

The exceptionally stable isomers A and B of (H2O)20 have been detected by their characteristic OH stretch absorption patterns.
A shuttle effect free lithium sulfur battery based on a hybrid electrolyte
Authors: Wang Qingsong , Jin Jun , Wu Xiangwei , Ma Guoqiang , Yang Jianhua , Wen Zhaoyin
Published: September 2014

A room temperature hybrid electrolyte based lithium–sulfur cell was successfully cycled with an excellent coulombic efficiency of 100%.
Stability enhancement of fluorophores for lighting up practical application in bioimaging
Authors: Wu Xumeng , Zhu Weihong
Published: September 2014

In this Highlight, we emphasize some representative strategies including nanoparticle-encapsulating dyes, dye-doped nanoparticles and molecular engineering for stabilizing fluorophores.
Surface modification and characterization of photon-upconverting nanoparticles for bioanalytical applications
Authors: Sedlmeier Andreas , Gorris Hans H.
Published: September 2014

A well-defined surface architecture is essential to generate water-dispersible UCNPs that are long-term stable and enable a wealth of bioanalytical applications.
Synergistic effect of PtSe2 and graphene sheets supported by TiO2 as cocatalysts synthesized via microwave techniques for improved photocatalytic activity
Authors: Ullah Kefayat , Ye Shu , Lei Zhu , Cho Kwang-Yeon , Oh Won-Chun
Published: September 2014

Here we report a new composite material consisting of TiO2 nanoparticles grown in the presence of a layered PtSe2/graphene hybrid as a high-performance photocatalytic material.
Thin-coated water soluble CdTeS alloyed quantum dots as energy donors for highly efficient FRET
Authors: Yahia-Ammar Akram , Nonat Aline M. , Boos Anne , Rehspringer Jean-Luc , Asfari Zouhair , Charbonnière Loïc J.
Published: September 2014

A model for the determination of the chemical composition and the size of CdTeS QDs is proposed and confirmed by FRET experiments.
Bis(acetylacetonato)bis(pyrazolato)ruthenate(iii) as a redox-active scorpionate ligand
Authors: Yoshida Jun , Sugawara Keisuke , Yuge Hidetaka , Okabayashi Jun
Published: September 2014

The octahedral Ru(iii) complex acts as a redox-active scorpionate ligand.
Doping and electronic properties of GaAs grown by close-spaced vapor transport from powder sources for scalable III–V photovoltaics
Authors: Ritenour Andrew J. , Boucher Jason W. , DeLancey Robert , Greenaway Ann L. , Aloni Shaul , Boettcher Shannon W.
Published: September 2014

We report the use of a simple close-spaced vapor transport technique for the growth of high-quality epitaxial GaAs films using potentially inexpensive GaAs powders as precursors.
Can Suillus granulatus (L.) Roussel be classified as a functional food?
Authors: Reis Filipa S. , Stojković Dejan , Barros Lillian , Glamočlija Jasmina , Ćirić Ana , Soković Marina , Martins Anabela , Vasconcelos M. Helena , Morales Patricia , Ferreira Isabel C. F. R.
Published: September 2014

Suillus granulatusproved to be a source of nutraceuticals and bioactive compounds.
The relationship between oxidation and hydrolysis in the conversion of cellulose in NaVO3–H2SO4 aqueous solution with O2
Authors: Niu Muge , Hou Yucui , Ren Shuhang , Wang Wenhua , Zheng Qitian , Wu Weize
Published: September 2014

Conversion of cellulose in NaVO3–H2SO4 aqueous solution with O2 is subject to competitive relationship between oxidation and hydrolysis.
Lignin: a nature-inspired sun blocker for broad-spectrum sunscreens
Authors: Qian Yong , Qiu Xueqing , Zhu Shiping
Published: September 2014

Lignin is evaluated as a nature-inspired broad-spectrum sun blocker in sunscreen lotions.
miRNA-1: functional roles and dysregulation in heart disease
Authors: Duan Lian , Xiong Xingjiang , Liu Yongmei , Wang Jie
Published: September 2014

microRNAs (miRNAs) are a class of small non-coding RNA molecules consisting of 19–22 nucleotides that play an important role in a variety of biological processes, including development, differentiation, apoptosis, cell proliferation and cellular senescence.
Bile acid amphiphiles with tunable head groups as highly selective antitubercular agents
Authors: Bansal Sandhya , Singh Manish , Kidwai Saqib , Bhargava Priyanshu , Singh Ashima , Sreekanth Vedagopuram , Singh Ramandeep , Bajaj Avinash
Published: September 2014

Hard-charged amphiphiles are highly selective against mycobacteria, whereas soft-charged amphiphiles are active against Gram-positive and Gram-negative bacteria.
Homologous 1,3,5-triarylpyrazolines: synthesis, CH⋯π interactions guided self-assembly and effect of alkyloxy chain length on DNA binding properties
Authors: Anam Faiza , Abbas Asghar , Lo Kong Mun , Zia-ur-Rehman Zia-ur-Rehman , Hameed Shahid , Naseer Muhammad Moazzam
Published: September 2014

The synthesis, CH⋯π interactions-driven self-assembled structure and DNA binding properties (105–106M−1binding constants) of new homologous 1,3,5-triaryl-2-pyrazolines are reported.
Mechanistic insights into B–H bond activation with the high-valent oxo-molybdenum complex MoO2Cl2
Authors: Huang Liangfang , Wei Haiyan
Published: September 2014

The ionic mechanistic model involving the heterolytic cleavage of the B–H bond is slightly energetically favorable than the [2+2] addition mechanism for the high-valent oxo-molybdenum complex MoO2Cl2activating the B–H bond.
Molybdenum disulfide (MoS2) nanoflakes as inherently electroactive labels for DNA hybridization detection
Authors: Loo Adeline Huiling , Bonanni Alessandra , Ambrosi Adriano , Pumera Martin
Published: September 2014

Herein, we propose a novel approach of employing molybdenum disulfide nanoflakes as inherently electroactive labels for the detection of DNA hybridization.
A general Pd/Cu-catalyzed C–H heteroarylation of 3-bromoquinolin-2(1H)-ones
Authors: Bruneau Alexandre , Brion Jean-Daniel , Messaoudi Samir , Alami Mouad
Published: September 2014

The Pd(OAc)2/CuI system effectively catalyzes the coupling of 3-bromoquinolin-2(1H)-ones with a series of azoles to give 3-(heteroaryl)quinolin-2(1H)-ones in good yields.
Enantioselective total syntheses of the proposed structures of prevezol B and evaluation of anti-cancer activity
Authors: Leung Anna E. , Rubbiani Riccardo , Gasser Gilles , Tuck Kellie L.
Published: September 2014

The first enantioselective total syntheses of the proposed structures of the natural product prevezol B are reported. This work has shown that the proposed structures of prevezol B are incorrect.
Role of carbon coating in improving electrochemical performance of Li-rich Li(Li0.2Mn0.54Ni0.13Co0.13)O2cathode
Authors: Song Bohang , Zhou Cuifeng , Chen Yu , Liu Zongwen , Lai Man On , Xue Junmin , Lu Li
Published: September 2014

Li-rich Li(Li0.2Mn0.54Ni0.13Co0.13)O2cathode coated with carbon layer has been prepared by a hydrothermal approach. The enhanced performance is attributed to the carbon layer and surface spinels on particles.
Restoration of the genuine electronic properties of functionalized single-walled carbon nanotubes
Authors: Um Jo-Eun , Chung Chan-Hwa , Lee Doh C. , Yoo Pil J. , Kim Woo-Jae
Published: September 2014

Annealing functionalized single-walled carbon nanotubes (SWNTs) at high temperatures, that is, above 400°C, effectively removes functional groups from the sidewalls of SWNTs and recovers their original optical and electrical properties.
Optimizing supercapacitor electrode density: achieving the energy of organic electrolytes with the power of aqueous electrolytes
Authors: Merrill M. D. , Montalvo E. , Campbell P. G. , Wang Y. M. , Stadermann M. , Baumann T. F. , Biener J. , Worsley M. A.
Published: September 2014

High-density electrodes allow aqueous-based supercapacitors to attain energy densities comparable to those of commercially-available organic-based supercapacitors with 10–100× greater power.
Hybrid hydrogel sheets that undergo pre-programmed shape transformations
Authors: Wei Zengjiang , Jia Zheng , Athas Jasmin , Wang Chaoyang , Raghavan Srinivasa R. , Li Teng , Nie Zhihong
Published: September 2014

This communication describes a novel strategy to achieve programmable shape transformation of hybrid hydrogel sheets by modulating both the in-plane and out-of-plane mismatches in mechanical properties.
High electrochemical performance in asymmetric supercapacitors using MWCNT/nickel sulfide composite and graphene nanoplatelets as electrodes
Authors: Singh Arvinder , Roberts Alexander J. , Slade Robert C. T. , Chandra Amreesh
Published: September 2014

A high-performance asymmetric supercapacitor was fabricated using MWCNTs/NiS composite and GNPs as electrodes, exhibiting high specific capacitance of ∼181 F g−1 at 1 A g−1 current density and excellent cyclic stability with 92% retention after 1000 cycles at 2 A g−1 current density.
Surface engineered angstrom thick ZnO-sheathed TiO2 nanowires as photoanodes for performance enhanced dye-sensitized solar cells
Authors: Ulusoy T. G. , Ghobadi A. , Okyay A. K.
Published: September 2014

This paper presents a systematic study on the effects of angstrom-thick atomic layer deposited (ALD) ZnO sheaths on hydrothermally-grown TiO2 nanowires (NWs) used as photoanodes in dye-sensitized solar cells (DSSCs).
Panchromatic Ru(ii) sensitizers bearing single thiocyanate for high efficiency dye sensitized solar cells
Authors: Wang Sheng-Wei , Chou Chun-Cheng , Hu Fa-Chun , Wu Kuan-Lin , Chi Yun , Clifford John N. , Palomares Emilio , Liu Shih-Hung , Chou Pi-Tai , Wei Tzu-Chien , Hsiao Ting-Yun
Published: September 2014

We report on a new series of Ru(ii) sensitizers PRT-21–PRT-24 suitable for high performance dye sensitized solar cells (DSCs).
Ultrasonic splicing of polymer optical fibres
Authors: Mizuno Y. , Ohara S. , Hayashi N. , Nakamura K.
Published: September 2014

A new method of splicing polymer optical fibres by irradiation of megahertz ultrasonic waves is demonstrated. The lowest connection loss of 1.5 dB is obtained at 2 MHz, and a high mechanical strength of 59 N (close to the strength of the base polymer) is achieved at 1 MHz. It is shown that the loss and strength are in a trade‐off relationship, and that the duration of ultrasonic irradiation has a certain optimal value of ∼1 s.
Broadband right‐angle transition from substrate‐integrated waveguide to rectangular waveguide
Authors: Li Teng , Dou Wenbin
Published: September 2014

A broadband right‐angle transition from a substrate‐integrated waveguide (SIW) to a rectangular waveguide (RWG) is proposed. A coupling aperture etched on the broad wall of the SIW and two stepped ridges embedded in the RWG flange are designed for good matching between both waveguides. A Ka‐band prototype is designed and fabricated. Good agreement between the measured and simulated results is obtained. The measured results show an insertion loss <0.55 dB and a return loss below −15 dB from 31.3 to 38.35 GHz. This broadband transition may be used in microwave and millimetre‐wave circuits and systems.
On‐chip integration of laser‐ablated zone plates for detection enhancement of InGaAs bow‐tie terahertz detectors
Authors: Minkevičius L. , Tamošiūnas V. , Madeikis K. , Voisiat B. , Kašalynas I. , Valušis G.
Published: September 2014

One order of magnitude detection enhancement of bow‐tie‐shaped InGaAs‐based terahertz detectors by on‐chip incorporation of the secondary diffractive optics is reported. Zone plates were produced directly on the bottom surface of 500 µm‐thick InP substrate using the direct laser write technique after an array of InGaAs detectors was formed on the front surface of the wafer. Measurements of detected signal dependence on the angle of the incident wave were performed at 0.76 THz and compared with finite‐difference time‐domain simulation results. Good correlation of the results shows that the observed enhancement is indeed caused by the focusing performance of the zone plate rather than by the exceptional sensitivity of the single detector.
High‐power VHF tunable filters with high selectivity
Authors: Zhao Zhi‐Yuan , Chen Jiang , Yang Lin , Chen Kun‐He
Published: September 2014

A tunable helical bandpass filter with high selectivity designed for 30–88 MHz operation is presented. The two‐pole tunable filter is discretely tuned by connecting PIN switched capacitor banks at the terminal ends of the helix. The filter schematic provides two finite transmission zeros located in the lower and upper stopbands, respectively. The experimental filter has an insertion loss between 1.65 and 2.75 dB with its return loss better than 13 dB. The 3‐dB fractional bandwidth of the filter is 3.3%–3.7% and the shape factor (BW30 dB/BW3 dB) is smaller than 5.5 over the entire tuning range. The input power handling capability is greater than 45 dBm. The measured results show good agreement with the simulated ones.
64 × 48 TOF sensor in 0.35 µm CMOS with high ambient light immunity
Authors: Davidovic M. , Seiter J. , Hofbauer M. , Gaberl W. , Schidl S. , Zimmermann H.
Published: September 2014

A multi‐pixel 64 × 48 time‐of‐flight (TOF) range sensor whose speciality is high immunity against ambient light is presented. The chip was fabricated in a 0.35 µm 1P4M CMOS process, whereby a single pixel occupies an area of 45 × 60 µm2 achieving a fill factor of 50%. The measured distance shows a 1σ deviation below 3.7 mm in the optimum operating range for the sensor. The measurement results show that the sensor successfully acquires the distance even when some parts of the scenery are illuminated with 180 klx ambient light. Furthermore, the most accurate method to characterise particular pixels in a multi‐pixel array is for the first time used in a multi‐pixel TOF sensor.
5 Gbit/s 2‐tap low‐swing voltage‐mode transmitter with least segmented voltage‐mode equalisation
Authors: Kwak Kang‐Sub , Hong Seong‐Kwan , Kwon Oh‐Kyong
Published: September 2014

A 2‐tap low‐swing voltage‐mode transmitter which compensates the loss of channel at high frequency is proposed. The output driver of the proposed 2‐tap transmitter consists of only two voltage‐mode drivers, and thereby the design complexity of the pre‐driver is greatly reduced compared with that of conventional 2N‐segmented voltage‐mode drivers, where N is the number of equalisation control bits. The output impedance of each voltage‐mode driver is adjusted not only to make the overall output impedance matched with the characteristic impedance of the channel, but also to achieve the desired equalisation coefficient by adopting the proposed calibration circuitry. With a high equalisation coefficient, the proposed output driver consumes less power compared with the hybrid voltage‐mode driver with current‐mode equalisation. The proposed transmitter is implemented using a 90 nm low‐power CMOS process technology and achieves 0.79 pJ/bit without equalisation and 0.98 pJ/bit with 6 dB equalisation, at the data rate of 5 Gbit/s.
Miniaturisation of artificial magnetic conductors: comparison methodology and realisation of compact unit cell
Authors: Grau M. , Serra R. , Parrón J.
Published: September 2014

A novel artificial magnetic conductor based on a low‐profile implementation of a capacitively loaded resonant structure is presented, with increased performance in terms of miniaturisation. In addition, a comprehensive analysis of all the parameters involved in downsizing is provided, establishing a fair methodology for comparing the performance of different size reduction strategies.
Multi‐scale saliency detection via inter‐regional shortest colour path
Authors: Guo Wenzhong , Sun Xiaolong , Niu Yuzhen
Published: September 2014

Saliency detection has attracted considerable attention, and numerous approaches aimed at locating meaningful regions in images have been presented. Nevertheless, accurate saliency detection algorithms remain in urgent demand. Many algorithms work well when dealing with simple images, but work poorly with complex images that contain small‐scale and high‐contrast structures. Moreover, most existing local and global regional saliency detection methods measure image saliency through region contrast. Such measurement is achieved by directly computing the difference between non‐adjacent regions. In this study, the authors introduce a new perspective for evaluating region contrast. We propose a novel multi‐scale saliency region detection method by optimising the shortest path of two non‐adjacent regions in the colour space and by measuring the region contrast from different scales. The final saliency maps indicate that the proposed method can work well with images containing small patches, but with high contrast. The proposed approach can also make the foreground significantly more uniform. Experimental results on three public benchmark datasets show that the proposed method achieves better precision–recall curve than some state‐of‐the‐art methods.
Image compression and encryption scheme using fractal dictionary and Julia set
Authors: Sun Yuanyuan , Xu Rudan , Chen Lina , Hu Xiaopeng
Published: September 2014

An efficient and secure environment is necessary for data transmission and storage, especially for large‐column multimedia data. In this study, a novel compression–encryption scheme is presented using a fractal dictionary and Julia set. For the compression in this scheme, fractal dictionary encoding not only reduces time consumption, but also gives good quality image reconstruction. For the encryption in the scheme, the key has large key space and high sensitivity, even to tiny perturbation. Besides, the stream cipher encryption and the diffusion process adopted in this study help spread perturbation in the plaintext, achieving high plain sensitivity and giving an effective resistance to chosen‐plaintext attacks.
Centralised model predictive controller design for wave energy converter arrays
Authors: Oetinger Daniela , Magaña Mario E. , Sawodny Oliver
Published: September 2014

Many recent works on wave energy conversion use a form of model predictive control (MPC) to maximise energy harvest. This active control strategy is generally used because it permits the inclusion of constraints that represent the physical limits of wave energy conversion devices in the optimisation algorithm. In this study, the authors present a centralised MPC design for an array configuration of wave energy converters. Its performance is evaluated via computer simulation and is compared against that of decentralised MPC and linear damping controller for several values of damping in both regular and irregular waves.
Detection performance analysis of recurrence quantification analysis measures for low observable target within sea clutter under different sea conditions
Authors: Feng Chen , Zheng Haiyong , Zhou Lijian , Cheng Junna
Published: September 2014

An approach based on recurrence quantification analysis (RQA) measures is proposed to detect the low observable target within sea clutter in this study. Based on the criterion named the fixed amount of nearest neighbours, recurrence plots (RPs) are constructed. RQA measures are used to describe the line structures of the RPs. According to the differences between the RQA measures of sea clutter with and without a target, the low observable target within sea clutter can be detected. Four sea clutter datasets under different sea conditions in the IPIX OHGR database are selected to analyse the target detection performance of RQA measures. Compared with the multifractal correlation spectrum approach and the cell average constant false alarm rate detector, the author's approach can achieve a higher detection probability. Furthermore, the authors analyse the receiver operating characteristic curves of RQA measures in all of polarisations under different sea conditions. The experimental results show that the horizontal–horizontal polarisation dataset and one of the horizontal–vertical and vertical–horizontal polarisation datasets should be selected for the target detection, and the significant wave height has a greater influence on the target detection performance than the wind speed does.
Wideband receiver with I/Q channels for multiple Nyquist zone coverage
Authors: Cheng Chi‐Hao
Published: September 2014

A digital wideband receiver signal processing technique using two I/Q channel‐based receivers with a sampling timing offset is proposed. With I/Q imbalance compensation, the proposed receiver can maintain high instantaneous dynamic range and cover multiple Nyquist zones thus reducing the receiver's sampling rate requirement. Simulation results are presented to verify validity of the proposed method. The limitations of the proposed method and possible solutions are also discussed.
Three‐dimensional inverse synthetic aperture radar imaging based on compressive sensing
Authors: Qiu Wei , Martorella Marco , Zhou Jianxiong , Zhao Hongzhong , Fu Qiang
Published: September 2014

Inverse synthetic aperture radar (ISAR) can form two‐dimensional (2D) electromagnetic images of a target, but it cannot provide the third dimensional information about the target. Conventional 3D turntable ISAR imaging requires data collection over densely azimuth‐elevation samples, which needs a large amount of data storage. In this study, an effective 3D ISAR imaging algorithm for turntable model based on compressive sensing is proposed, which exploits the sparsity in the image domain to achieve 3D reconstruction by using a limited number of measurements. Firstly, the 3D data tensor is converted into a 2D matrix by stacking slices of data along one specific dimension; then a 2D optimisation reconstruction approach is applied to solve a sparsity‐driven optimisation problem to obtain the 2D distribution of the scatterers. Lastly, 3D ISAR images are generated by rearranging the scatterer distribution in the 2D map into a 3D volume. This imaging scheme only needs a small number of measurements, and reduces the required memory and computational burden significantly. Simulation results are finally shown to validate the proposed algorithm.
Robust direction of arrival estimate method in FM‐based passive bistatic radar with a four‐element Adcock antenna array
Authors: Xiao‐Yong Lv , Jun Wang , Jue Wang
Published: September 2014

This study examines the problem of direction of arrival (DOA) estimation in FM‐based passive bistatic radar using a four‐element Adcock antenna array. The authors investigate the influence of the target echo, involved in the reference signal, on the DOA estimation of the corresponding target considered. Analysis shows that, unlike the pure reference signal case, a weak target echo involved in the reference signal may not affect the detection of the corresponding target. It can often have a significant impact on the estimation of a target's DOA; thus typical DOA estimate methods degrade heavily. A robust method is proposed to cope with this problem. Simulation and experimental results demonstrate the effectiveness of the method.
Fast Si (100) etching with a smooth surface near the boiling temperature in surfactant‐modified tetramethylammonium hydroxide solutions
Authors: Tang Bin , Sato Kazuo , Zhang De , Cheng Yongsheng
Published: September 2014

The etching characteristics of the commonly utilised Si (100) facet at high temperatures near the boiling point in surfactant‐modified tetramethylammonium hydroxide (TMAH) solutions are investigated. Solutions of 25 wt% TMAH are selected because of the etching stability and the rate of addition of the surfactant Triton‐X‐100 [C14H22O(C2H4O)n, n = 9–10] ranges from 0.01 to 1% v/v. The etching rates of Si (100) facets close to the boiling point are three to four times higher than those at 80°C in the surfactant‐modified 25 wt% TMAH solutions. In particular, at 115°C, the very near temperature of the boiling point, the silicon sample possessing a high etching rate of 1.45 μm/min and the smooth etched Si (100) surface with an average roughness of about 1 nm is obtained. Moreover, the samples do not demonstrate much undercut difference at the etched convex corners near the boiling point. These results are useful for the fabrication of microelectromechanical systems and indeed provide an efficient etching method for industry products.
Extinction coefficient of water‐based multi‐walled carbon nanotube nanofluids for application in direct‐absorption solar collectors
Authors: Lee Seung‐Hyun , Kim Hyun Jin , Kim Kyu Han , Jang Seok Pil
Published: September 2014

In this reported work, the extinction coefficient of water‐based nanofluids containing multi‐walled carbon nanotubes (MWNCTs) has been experimentally measured. The MWCNTs were dispersed in deionised water with a surfactant, hexadecyltrimethyl‐ammonium bromide, and they were homogenised by a bath‐type ultrasonicator and a mechanical stirrer. The characteristics of MWCNTs suspended in the nanofluids were examined by transmission electron microscopy and scanning electron microscopy images and their hydrodynamic particle size was measured by a particle size analyser. The extinction coefficient of nanofluids was measured by an in‐house developed apparatus at a single wavelength (632.8 nm) based on the Lambert‐Beer principle. With the experimentally obtained extinction coefficient, the efficiency of a flat‐plate type direct‐absorption solar collector (DASC) was theoretically estimated. For this purpose, a modified analytical solution of the DASC efficiency is presented by assuming that the extinction coefficient is not a function of the wavelength. Finally, the efficiency of DASC is demonstrated according to the nanotube volume fractions. The results show that the DASC concept can further improve the efficiency of the conventional flat‐plate type solar collectors.