bluuebunny/crossref_metadata_2025 huggingface dataset:
Strong association of the polymorphisms in PBEF1 and knee OA risk: a two-stage population-based study in China
Authors: Chu Minjie , Rong Jiesheng , Wang Yidan , Zhu Lin , Xing Baifen , Tao Yuchun , Zhuang Xun , Zhao Yashuang , Jiang Liying
Published: January 2016

The association of Pre-B cell colony enhancing factor 1 (PBEF1) with obesity, together with its pro-inflammatory properties suggests that PBEF1 might be another crucial mediator that links inflammation with obesity and primary osteoarthritis (OA). We hypothesized that polymorphisms in PBEF1 may modify the risk of developing OA. Thus we systematically screened 4 tagging polymorphisms (rs4730153, rs2058540, rs3801267 and rs16872158) in PBEF1 and evaluated the association between the genetic variants and OA risk in a two-stage case-control study including 196 cases and 442 controls in the first stage and 143 cases and 238 controls in the second stage. In the first stage, two SNPs (rs4730153 and rs16872158) were found to be potentially associated with OA risk (P < 0.05), which were further confirmed in the second stage with similar effects. After combining the two stages, we found that rs4730153 was significantly associated with decreased risk of OA in an additive genetic model (P < 0.05), while rs16872158 showed increased risk of developing OA (P < 0.05). Combined analysis of these 2 SNPs showed a significant allele-dosage association between the number of risk alleles and OA risk (Ptrend = 5.25 × 10−5). These findings indicate that genetic variants in PBEF1 gene may modify individual susceptibility to OA in the Chinese population.
Correction: Corrigendum: IL-1α is a DNA damage sensor linking genotoxic stress signaling to sterile inflammation and innate immunity
Authors: Cohen Idan , Rider Peleg , Vornov Elena , Tomas Martin , Tudor Cicerone , Wegner Mareike , Brondani Lydia , Freudenberg Marina , Mittler Gerhard , Ferrando-May Elisa , Dinarello Charles A. , Apte Ron N. , Schneider Robert
Published: January 2016

Environmental signals can be translated into chromatin changes, which alter gene expression. Here we report a novel concept that cells can signal chromatin damage from the nucleus back to the surrounding tissue through the cytokine interleukin-1alpha (IL-1α). Thus, in addition to its role as a danger signal, which occurs when the cytokine is passively released by cell necrosis, IL-1α could directly sense DNA damage and act as signal for genotoxic stress without loss of cell integrity. Here we demonstrate localization of the cytokine to DNA-damage sites and its subsequent secretion. Interestingly, its nucleo-cytosolic shuttling after DNA damage sensing is regulated by histone deacetylases (HDAC) and IL-1α acetylation. To demonstrate the physiological significance of this newly discovered mechanism, we used IL-1α knockout mice and show that IL-1α signaling after UV skin irradiation and DNA damage is important for triggering a sterile inflammatory cascade in vivo that contributes to efficient tissue repair and wound healing.
3D tumor spheroid models for in vitro therapeutic screening: a systematic approach to enhance the biological relevance of data obtained
Authors: Zanoni Michele , Piccinini Filippo , Arienti Chiara , Zamagni Alice , Santi Spartaco , Polico Rolando , Bevilacqua Alessandro , Tesei Anna
Published: January 2016

The potential of a spheroid tumor model composed of cells in different proliferative and metabolic states for the development of new anticancer strategies has been amply demonstrated. However, there is little or no information in the literature on the problems of reproducibility of data originating from experiments using 3D models. Our analyses, carried out using a novel open source software capable of performing an automatic image analysis of 3D tumor colonies, showed that a number of morphology parameters affect the response of large spheroids to treatment. In particular, we found that both spheroid volume and shape may be a source of variability. We also compared some commercially available viability assays specifically designed for 3D models. In conclusion, our data indicate the need for a pre-selection of tumor spheroids of homogeneous volume and shape to reduce data variability to a minimum before use in a cytotoxicity test. In addition, we identified and validated a cytotoxicity test capable of providing meaningful data on the damage induced in large tumor spheroids of up to diameter in 650 μm by different kinds of treatments.
Future Warming Patterns Linked to Today’s Climate Variability
Authors: Dai Aiguo
Published: January 2016

The reliability of model projections of greenhouse gas (GHG)-induced future climate change is often assessed based on models’ ability to simulate the current climate, but there has been little evidence that connects the two. In fact, this practice has been questioned because the GHG-induced future climate change may involve additional physical processes that are not important for the current climate. Here I show that the spatial patterns of the GHG-induced future warming in the 21st century is highly correlated with the patterns of the year-to-year variations of surface air temperature for today’s climate, with areas of larger variations during 1950–1979 having more GHG-induced warming in the 21st century in all climate models. Such a relationship also exists in other climate fields such as atmospheric water vapor and it is evident in observed temperatures from 1950–2010. The results suggest that many physical processes may work similarly in producing the year-to-year climate variations in the current climate and the GHG-induced long-term changes in the 21st century in models and in the real world. They support the notion that models that simulate present-day climate variability better are likely to make more reliable predictions of future climate change.
REPLACR-mutagenesis, a one-step method for site-directed mutagenesis by recombineering
Authors: Trehan Ashutosh , Kiełbus Michał , Czapinski Jakub , Stepulak Andrzej , Huhtaniemi Ilpo , Rivero-Müller Adolfo
Published: January 2016

Mutagenesis is an important tool to study gene regulation, model disease-causing mutations and for functional characterisation of proteins. Most of the current methods for mutagenesis involve multiple step procedures. One of the most accurate methods for genetically altering DNA is recombineering, which uses bacteria expressing viral recombination proteins. Recently, the use of in vitro seamless assembly systems using purified enzymes for multiple-fragment cloning as well as mutagenesis is gaining ground. Although these in vitro isothermal reactions are useful when cloning multiple fragments, for site-directed mutagenesis it is unnecessary. Moreover, the use of purified enzymes in vitro is not only expensive but also more inaccurate than the high-fidelity recombination inside bacteria. Here we present a single-step method, named REPLACR-mutagenesis (Recombineering of Ends of linearised PLAsmids after PCR), for creating mutations (deletions, substitutions and additions) in plasmids by in vivo recombineering. REPLACR-mutagenesis only involves transformation of PCR products in bacteria expressing Red/ET recombineering proteins. Modifications in a variety of plasmids up to bacterial artificial chromosomes (BACs; 144 kb deletion) have been achieved by this method. The presented method is more robust, involves fewer steps and is cost-efficient.
Picosecond x-ray strain rosette reveals direct laser excitation of coherent transverse acoustic phonons
Authors: Lee Sooheyong , Williams G. Jackson , Campana Maria I. , Walko Donald A. , Landahl Eric C.
Published: January 2016

Using a strain-rosette, we demonstrate the existence of transverse strain using time-resolved x-ray diffraction from multiple Bragg reflections in laser-excited bulk gallium arsenide. We find that anisotropic strain is responsible for a considerable fraction of the total lattice motion at early times before thermal equilibrium is achieved. Our measurements are described by a new model where the Poisson ratio drives transverse motion, resulting in the creation of shear waves without the need for an indirect process such as mode conversion at an interface. Using the same excitation geometry with the narrow-gap semiconductor indium antimonide, we detected coherent transverse acoustic oscillations at frequencies of several GHz.
Nutritional conditions regulate transcriptional activity of SF-1 by controlling sumoylation and ubiquitination
Authors: Lee Jiwon , Yang Dong Joo , Lee Syann , Hammer Gary D. , Kim Ki Woo , Elmquist Joel K.
Published: January 2016

Steroidogenic factor 1 (SF-1) is a transcription factor expressed in the ventral medial nucleus of the hypothalamus that regulates energy homeostasis. However, the molecular mechanisms of SF-1 in the control of energy balance are largely unknown. Here, we show that nutritional conditions, such as the presence or absence of serum, affect SF-1 action. Serum starvation significantly decreased hypothalamic SF-1 levels by promoting ubiquitin-dependent degradation and sumoylation was required for this process. SF-1 transcriptional activity was also differentially regulated by nutritional status. Under normal conditions, the transcriptional activity of hypothalamic SF-1 was activated by SUMO, but this was attenuated during starvation. Taken together, these results indicate that sumoylation and ubiquitination play crucial roles in the regulation of SF-1 function and that these effects are dependent on nutritional conditions, further supporting the importance of SF-1 in the control of energy homeostasis.
Forests as a natural seismic metamaterial: Rayleigh wave bandgaps induced by local resonances
Authors: Colombi Andrea , Roux Philippe , Guenneau Sebastien , Gueguen Philippe , Craster Richard V.
Published: January 2016

We explore the thesis that resonances in trees result in forests acting as locally resonant metamaterials for Rayleigh surface waves in the geophysics context. A geophysical experiment demonstrates that a Rayleigh wave, propagating in soft sedimentary soil at frequencies lower than 150 Hz, experiences strong attenuation, when interacting with a forest, over two separate large frequency bands. This experiment is interpreted using finite element simulations that demonstrate the observed attenuation is due to bandgaps when the trees are arranged at the sub-wavelength scale with respect to the incident Rayleigh wave. The repetitive bandgaps are generated by the coupling of the successive longitudinal resonances of trees with the vertical component of the Rayleigh wave. For wavelengths down to 5 meters, the resulting bandgaps are remarkably large and strongly attenuating when the acoustic impedance of the trees matches the impedance of the soil. Since longitudinal resonances of a vertical resonator are inversely proportional to its length, a man-made engineered array of resonators that attenuates Rayleigh waves at frequency ≤10 Hz could be designed starting from vertical pillars coupled to the ground with longitudinal resonance ≤10 Hz.
Polarization-sensitive optical projection tomography for muscle fiber imaging
Authors: Fang Mengjie , Dong Di , Zeng Chaoting , Liang Xiao , Yang Xin , Arranz Alicia , Ripoll Jorge , Hui Hui , Tian Jie
Published: January 2016

Optical projection tomography (OPT) is a tool used for three-dimensional imaging of millimeter-scale biological samples, with the advantage of exhibiting isotropic resolution typically in the micron range. OPT can be divided into two types: transmission OPT (tOPT) and emission OPT (eOPT). Compared with eOPT, tOPT discriminates different tissues based on their absorption coefficient, either intrinsic or after specific staining. However, it fails to distinguish muscle fibers whose absorption coefficients are similar to surrounding tissues. To circumvent this problem, in this article we demonstrate a polarization sensitive OPT system which improves the detection and 3D imaging of muscle fibers by using polarized light. We also developed image acquisition and processing protocols that, together with the system, enable the clear visualization of muscles. Experimental results show that the muscle fibers of diaphragm and stomach, difficult to be distinguished in regular tOPT, were clearly displayed in our system, proving its potential use. Moreover, polarization sensitive OPT was fused with tOPT to investigate the stomach tissue comprehensively. Future applications of polarization sensitive OPT could be imaging other fiber-like structures such as myocardium or other tissues presenting high optical anisotropy.
A rapid and novel method for predicting nicotine alkaloids in tobacco through electronic nose and partial least-squares regression analysis
Authors: Lin Shunshun , Zhang Xiaoming
Published: January 2016

Alkaloid levels in tobacco are of great concern owing to nicotine addiction and associated diseases.
Seedless growth of ZnO nanorods on TiO2 fibers by chemical bath deposition
Authors: Liu Benxue , Feng Cong , Zhang Xingshuang , Zhu Luyi , Wang Xinqiang , Zhang Guanghui , Xu Dong
Published: January 2016

Seedless growth of ZnO nanorods on TiO2 microfibers was reported, and the growth mechanism was demonstrated.
Fast and efficient synthesis of a host guest system: a mechanochemical approach
Authors: Wilke Manuel , Klimakow Maria , Rademann Klaus , Emmerling Franziska
Published: January 2016

In situ investigation and elucidation of the formation of a POM@MOF host guest system obtained by mechanosynthesis.
On the stability of manganese tris(β-diketonate) complexes as redox mediators in DSSCs
Authors: Carli Stefano , Benazzi Elisabetta , Casarin Laura , Bernardi Tatiana , Bertolasi Valerio , Argazzi Roberto , Caramori Stefano , Bignozzi Carlo Alberto
Published: January 2016

Mn(iii)(β-diketonato)3 complexes lead to trans-coordinated species in the presence of TBP. An alternative passivation strategy was explored.
Electrochemistry of ferrocene derivatives on highly oriented pyrolytic graphite (HOPG): quantification and impacts of surface adsorption
Authors: Cuharuc Anatolii S. , Zhang Guohui , Unwin Patrick R.
Published: January 2016

The adsorption of three ferrocene derivatives on graphite surfaces can be detected and quantified by cyclic voltammetry.
Shape selective properties of the Al-fumarate metal–organic framework in the adsorption and separation of n-alkanes, iso-alkanes, cyclo-alkanes and aromatic hydrocarbons
Authors: Bozbiyik Belgin , Lannoeye Jeroen , De Vos Dirk E. , Baron Gino V. , Denayer Joeri F. M.
Published: January 2016

Adsorption properties of a wide range of hydrocarbon adsorbates in the Al-fumarate metal–organic framework are reported. Trends in adsorption behaviour are related to the sorbate's molecular properties and as well as the properties of this MOF.
Distinct structural and dynamical difference between supercooled and normal liquids of hydrogen molecules
Authors: Hyeon-Deuk Kim , Ando Koji
Published: January 2016

The recently developed quantum molecular dynamics method including nuclear quantum effects demonstrated that supercooled hydrogens exhibit intrinsic properties including a precursor of superfluidity which neither normal hydrogen liquid nor solid possesses.
CPh3 as a functional group in P-heterocyclic chemistry: elimination of HCPh3 in the reaction of P-CPh3 substituted Li/Cl phosphinidenoid complexes with Ph2CO
Authors: García C. Murcia , Ferao A. Espinosa , Schnakenburg G. , Streubel R.
Published: January 2016

Li/Cl phosphinidenoid complexes 2a–c react with benzaldehyde to give 3a–c, but with benzophenone formation of complexes 4 and 5 was observed, the latter revealing the elimination of HCPh3.
Impact of chemical composition of ecotoxicological test media on the stability and aggregation status of silver nanoparticles
Authors: Metreveli George , Frombold Bianca , Seitz Frank , Grün Alexandra , Philippe Allan , Rosenfeldt Ricki R. , Bundschuh Mirco , Schulz Ralf , Manz Werner , Schaumann Gabriele E.
Published: January 2016

Aggregation status of Ag NPs in ecotoxicological test media is controlled by the Ca2+/Mg2+ ratio, presence of Cl− and Br− and NOM quality.
Sheath flow SERS for chemical profiling in urine
Authors: Riordan Colleen M. , Jacobs Kevin T. , Negri Pierre , Schultz Zachary D.
Published: January 2016

The molecular specificity and sensitivity of surface enhanced Raman scattering (SERS) makes it an attractive method for biomedical diagnostics. Here we present results demonstrating the utility and complications for SERS characterization in urine. The chemical fingerprint characteristics of Raman spectra suggest its use as a label free diagnostic; however, the complex composition of biological fluids presents a tremendous challenge. In particular, the limited number of surface sites and competing absorption tend to mask the presence of analytes in solution, particularly when the solution contains multiple analytes. To address these problems and characterize biological fluids we have demonstrated a sheath-flow interface for SERS detection. This sheath-flow SERS interface uses hydrodynamic focusing to confine analyte molecules eluting out of a column onto a planar SERS substrate where the molecules are detected by their intrinsic SERS signal. In this report we compare the direct detection of benzoylecgonine in urine using DSERS with chemical profiling by capillary zone electrophoresis and sheath-flow SERS detection. The SERS spectrum from the observed migration peaks can identify benzoylecgonine and other distinct spectra are also observed, suggesting improved chemical diagnostics in urine. With over 2000 reported compounds in urine, identification of each of the detected species is an enormous task. Nonetheless, these samples provide a benchmark to establish the potential clinical utility of sheath-flow SERS detection.
Stabilization of bacterially expressed erythropoietin by single site-specific introduction of short branched PEG chains at naturally occurring glycosylation sites
Authors: Hoffmann E. , Streichert K. , Nischan N. , Seitz C. , Brunner T. , Schwagerus S. , Hackenberger C. P. R. , Rubini M.
Published: January 2016

Erythropoietin (EPO) with single small branched PEG chains installed by the Staudinger-phosphite reaction leads to enhanced solubility, stability and intactin vitrobioactivity.
Boron-doped diamond as a sensor for the classification of carbamate pesticides using a chemometric approach
Authors: Selva Thiago Matheus Guimarães , Paixão Thiago Regis Longo Cesar da
Published: January 2016

Electrochemical sensor for the classification of carbamate pesticides.
Tuning Ag29 nanocluster light emission from red to blue with one and two-photon excitation
Authors: Russier-Antoine Isabelle , Bertorelle Franck , Hamouda Ramzi , Rayane Driss , Dugourd Philippe , Sanader Željka , Bonačić-Koutecký Vlasta , Brevet Pierre-François , Antoine Rodolphe
Published: January 2016

We demonstrate that the tuning of the light emission from red to blue in dihydrolipoic acid (DHLA) capped Ag29 nanoclusters can be trigged with one and two photon excitations.
Size-controllable synthesis of Bi/Bi2O3heterojunction nanoparticles using pulsed Nd:YAG laser deposition and metal–semiconductor-heterojunction-assisted photoluminescence
Authors: Patil Ranjit A. , Wei Mao-Kuo , Yeh P.-H. , Liang Jyun-Bo , Gao Wan-Ting , Lin Jin-Han , Liou Yung , Ma Yuan-Ron
Published: January 2016

The PL spectra of Bi/Bi2O3heterojunction nanoparticles, and the PL emission-enhanced mechanism in metal–semiconductor heterojunctions.
Improving the cold flow properties of high-proportional waste cooking oil biodiesel blends with mixed cold flow improvers
Authors: Zhao Weina , Xue Yuan , Ma Peng , Ma Wenfei , Wang Jieni , Lu Deli , Han Sheng
Published: January 2016

This study was conducted to improve the cold flow properties of biodiesel obtained from waste cooking oil.
Enhancement of the rate performance of plasma-treated platelet carbon nanofiber anodes in lithium-ion batteries
Authors: Han Yu-Jin , Lee Choonghyeon , Seo Young Deok , Nakabayashi Koji , Miyawaki Jin , Santamaría Ricardo , Menéndez Rosa , Jang Jyongsik , Yoon Seong-Ho
Published: January 2016

Brief C4F8plasma exposure on platelet carbon nanofibers can lead to fabrication of novel LIB anodes with enhanced rate performances.
Design, synthesis and RAFT polymerisation of a quinoline-based monomer for use in metal-binding composite microfibers
Authors: Isakova Anna , Efremova Olga , Pullan Nikki , Lüer Larry , Topham Paul D.
Published: January 2016

Metal-binding polymer fibres have attracted major attention for diverse applications in membranes for metal sequestration from waste waters, non-woven wound dressings, matrices for photocatalysis, and many more.
A review of research on the teaching and learning of chemical kinetics
Authors: Bain Kinsey , Towns Marcy H.
Published: January 2016

We review literature on the teaching and learning of chemical kinetics at both the secondary and tertiary levels. Our aim in doing so is to summarize research literature, synthesize recommendations for future research, and suggest implications for practitioners. Two main bodies of literature emerged from the chemical kinetics education research: student understanding and instructional approaches to teaching. The student understanding findings are discussed in light of the anchoring concepts content map for general chemistry. We also review relevant literature about research on undergraduate mathematics education, as mathematics is often used as the primary language of communicating chemical kinetics. Finally, we discuss directions for future research and implications for practice.
Design and synthesis of biphenyl and biphenyl ether inhibitors of sulfatases
Authors: Reuillon Tristan , Alhasan Sari F. , Beale Gary S. , Bertoli Annalisa , Brennan Alfie , Cano Celine , Reeves Helen L. , Newell David R. , Golding Bernard T. , Miller Duncan C. , Griffin Roger J.
Published: January 2016

Two series of inhibitors of sulfatase 2, ARSA and ARSB were designed based on biphenyl and biphenyl ether scaffolds substituted with e.g. sulfamate and carboxylate groups.
A visible-light-promoted radical reaction system for azidation and halogenation of tertiary aliphatic C–H bonds
Authors: Wang Yaxin , Li Guo-Xing , Yang Guohui , He Gang , Chen Gong
Published: January 2016

A highly tunable visible-light-promoted reaction system for the radical-mediated functionalization of tertiary aliphatic C–H bonds of complex substrates has been developed.
Coupling the folding of a β-hairpin with chelation-enhanced luminescence of Tb(iii) and Eu(iii) ions for specific sensing of a viral RNA
Authors: Penas Cristina , Mascareñas José L. , Vázquez M. Eugenio
Published: January 2016

Rational modification of a natural RNA-binding peptide with a lanthanide EDTA chelator, and a phenanthroline ligand yields a highly selective luminescent sensor.
Toward high performance indacenodithiophene-based small-molecule organic solar cells: investigation of the effect of fused aromatic bridges on the device performance
Authors: Wang Jin-Liang , Xiao Fei , Yan Jun , Liu Kai-Kai , Chang Zheng-Feng , Zhang Ru-Bo , Wu Hong-Bin , Cao Yong
Published: January 2016

Here we report the synthesis of a pair of D1–A-bridge–D2-bridge–A–D1 type small molecules, which have different π-conjugated bridges and investigated the effects on their photovoltaic properties.
Enhanced charge transfer with Ag grids at electrolyte/electrode interfaces in solid oxide fuel cells
Authors: Choi Mingi , Hwang Sangyeon , Byun Doyoung , Lee Wonyoung
Published: January 2016

This paper demonstrated the effect of Ag grids at the electrolyte/electrode interfaces on the electrochemical performance of solid oxide fuel cells (SOFCs).
Biodegradable PEI modified complex micelles as gene carriers with tunable gene transfection efficiency for ECs
Authors: Lv Juan , Yang Jing , Hao Xuefang , Ren Xiangkui , Feng Yakai , Zhang Wencheng
Published: January 2016

In recent years, gene therapy has evoked an increasing interest in clinical treatments of coronary diseases because it is a potential strategy to realize rapid endothelialization of artificial vascular grafts.
Impedance‐compensated grid synchronisation for extending the stability range of weak grids with voltage source converters
Authors: Suul Jon Are , D'Arco Salvatore , Rodríguez Pedro , Molinas Marta
Published: January 2016

This paper demonstrates how the range of stable power transfer in weak grids with voltage source converters (VSCs) can be extended by modifying the grid synchronisation mechanism of a conventional synchronous reference frame phase locked loop (PLL). By introducing an impedance‐conditioning term in the PLL, the VSC control system can be virtually synchronised to a stronger point in the grid to counteract the instability effects caused by high grid impedance. To verify the effectiveness of the proposed approach, the maximum static power transfer capability and the small‐signal stability range of a system with a VSC HVDC terminal connected to a weak grid are calculated from an analytical model with different levels of impedance‐conditioning in the PLL. Such calculations are presented for two different configurations of the VSC control system, showing how both the static power transfer capability and the small‐signal stability range can be significantly improved. The validity of the stability assessment is verified by time‐domain simulations in the Matlab/Simulink environment.
Design of a four‐element multiple‐input–multiple‐output antenna for compact long‐term evolution small‐cell base stations
Authors: Chen Yen‐Sheng , Chang Cheng‐Pang
Published: January 2016

This study presents a multiple‐input–multiple‐output (MIMO) antenna for compact small‐cell base stations operating in the long‐term evolution (LTE) standard. This MIMO antenna comprises four unit antenna elements, targeted at the frequency band of LTE700/850/900 (698–960 MHz). In comparison with the state‐of‐the‐art MIMO antennas covering these frequency bands, the proposed design enables the maximum number of antenna elements, yet it occupies a compact volume of only π × 802 × 50 mm3 (π × 0.182 × 0.11 λ3), which is the most miniature electrical configuration to date. The unit antenna element consists of a monopole antenna with a sleeve attached to each side, fed by a coaxial cable. Since the spacing between antenna elements is so small (0.24 λ), this work uses four miniature and wideband defected ground structures (DGSs) to reduce the mutual coupling; moreover, although the DGSs adversely alter the impedance matching of unit element, the authors applied multi‐objective fractional factorial design to achieve isolation enhancement and bandwidth preservation simultaneously. Accordingly, the optimised MIMO antenna shows desired –10 dB impedance bandwidth and sufficient isolation in the targeted frequency band. In addition, the radiation patterns, antenna efficiency, and the signal correlation coefficients are measured and evaluated.
Experimental study on performance assessment of Savonius rotor type wave energy converter in an experimental wave flume
Authors: Tutar Mustafa , Veci Inaki
Published: January 2016

The power generation of regular water waves from a horizontal‐axis single Savonius rotor is experimentally investigated in an experimental wave flume in the context of the performance assessment of the rotor in intermediate‐to‐shallow water depths for different parametric conditions. A number of prototypes with multiple blades of 3–5 with the same diameter and blade curvature angle are fabricated in‐house and tested to measure both the long‐term average torque and power generated at different submergence levels, wave heights and wave periods. The experiments are performed in the wave‐current flume equipped with a piston‐type wave maker with an active wave absorption capability. The energy performance of the rotor is comparatively assessed for each experimental test case based on quantitative comparison of obtained wave‐to‐mechanical energy conversion efficiency (ECE) to suggest a possible optimum blade number, positioning and wave physical conditions for the investigated range of wave flow characteristics. It is found that higher ECE values can be achieved at higher wave heights and blade numbers for the lower wave periods when the rotor is placed at the water surface and/or just below the surface. This study provides a proper guideline for performance analysis of such device(s) for further studies.
Resonance effects in elastic cross sections for electron scattering on pyrimidine: Experiment and theory
Authors: Regeta Khrystyna , Allan Michael , Winstead Carl , McKoy Vincent , Mašín Zdeněk , Gorfinkiel Jimena D.
Published: January 2016

We measured differential cross sections for elastic (rotationally integrated) electron scattering on pyrimidine, both as a function of angle up to 180∘ at electron energies of 1, 5, 10, and 20 eV and as a function of electron energy in the range 0.1–14 eV. The experimental results are compared to the results of the fixed-nuclei Schwinger variational and R-matrix theoretical methods, which reproduce satisfactorily the magnitudes and shapes of the experimental cross sections. The emphasis of the present work is on recording detailed excitation functions revealing resonances in the excitation process. Resonant structures are observed at 0.2, 0.7, and 4.35 eV and calculations for different symmetries confirm their assignment as the X̃2A2, Ã2B1, and B̃2B1 shape resonances. As a consequence of superposition of coherent resonant amplitudes with background scattering the B̃2B1 shape resonance appears as a peak, a dip, or a step function in the cross sections recorded as a function of energy at different scattering angles and this effect is satisfactorily reproduced by theory. The dip and peak contributions at different scattering angles partially compensate, making the resonance nearly invisible in the integral cross section. Vibrationally integrated cross sections were also measured at 1, 5, 10 and 20 eV and the question of whether the fixed-nuclei cross sections should be compared to vibrationally elastic or vibrationally integrated cross section is discussed.
Experimental study on interaction and coalescence of synchronized multiple bubbles
Authors: Cui P. , Wang Q. X. , Wang S. P. , Zhang A. M.
Published: January 2016

Experiments are carried out on the interaction and coalescence of two, three, and four bubbles with approximately the same sizes, distributed evenly and symmetrically. The bubbles are generated simultaneously by electric discharges, using an in-house designed series circuit, and their interaction is captured using a high-speed camera. Particular attentions are paid to if/when coalescence of bubbles happens and the motion of the joined bubbles. Some new features are observed, which depend mainly on the dimensionless distance γbb = dbb/Rmax, where dbb is the inter-bubble distance and Rmax is the maximum bubble radius. For γbb > 2, a jet forms and penetrates each side bubble, directed to the center of the configuration, resulting in a protrusion. Towards the end of collapse, a large portion of bubble gases is compressed into the protrusion from the main part of the toroidal bubble. For γbb < 2, the bubbles coalesce during expansion, and the part of the joined bubble’s surface distal from the center of the configuration collapses faster than elsewhere. The experiments show that the oscillation period of multi-bubbles does not change appreciably without coalescence but increases significantly with coalescence. For three bubbles initiated at collinear positions with γbb > 2, the jets that form from the side bubbles are towards the middle, and the middle bubble splits into two parts, moving towards the two side bubbles. For γbb < 2, the side bubbles merge with the middle bubble during expansion, forming an ellipsoid bubble; the joined bubble collapses predominantly from two sides, where two inward jets form towards the end of collapse.
New method of plasma immersion ion implantation and also deposition of industrial components using tubular fixture and plasma generated inside the tube by high voltage pulses
Authors: Ueda Mario , Silva Ataide Ribeiro da , Pillaca Elver J. D. M. , Mariano Samantha F. M. , Oliveira Rogério de Moraes , Rossi José Osvaldo , Lepienski Carlos Mauricio , Pichon Luc
Published: January 2016

A new method of Plasma Immersion Ion Implantation (PIII) and deposition (PIII and D) for treating industrial components in the batch mode has been developed. A metal tubular fixture is used to allocate the components inside, around, and along the tube, exposing only the parts of each component that are to be ion implanted to the plasma. Hollow cathode-like plasma is generated only inside the tube filled with the desired gas, by applying high negative voltage pulses to the hollow cylindrical fixture which is insulated from the vacuum chamber walls. This is a very convenient method of batch processing of industrial parts by ion implantation, in which a large number of small to medium sized components can be treated by PIII and PIII and D, very quickly, efficiently, and also at low cost.
Absolute cross sections for electronic excitation of pyrimidine by electron impact
Authors: Regeta Khrystyna , Allan Michael , Mašín Zdeněk , Gorfinkiel Jimena D.
Published: January 2016

We measured differential cross sections for electron-impact electronic excitation of pyrimidine, both as a function of electron energy up to 18 eV, and of scattering angle up to 180°. The emphasis of the present work is on recording detailed excitation functions revealing resonances in the excitation process. The differential cross sections were summed to obtain integral cross sections. These are compared to results of R-matrix calculations, which successfully reproduce both the magnitude of the cross section and the major resonant features. Comparison of the experiment to the calculated contributions of different symmetries to the integral cross section permitted assignment of several features to specific core-excited resonances. Comparison of the resonant structure of pyrimidine with that of benzene revealed pronounced similarities and thus a dominant role of π–π∗ excited states and resonances. Electron energy loss spectra were measured as a preparation for the cross section measurements and vibrational structure was observed for some of the triplet states. A detailed analysis of the electronic excited states of pyrimidine is also presented.
Snap-off in constricted capillary with elastic interface
Authors: Hoyer P. , Alvarado V. , Carvalho M. S.
Published: January 2016

Snap-off of bubbles and drops in constricted capillaries occurs in many different situations, from bio-fluid to multiphase flow in porous media. The breakup process has been extensively analyzed both by theory and experiments, but most work has been limited to pure interfaces, at which the surface stress is isotropic and fully defined by the interfacial tension and interface curvature. Complex interfaces may present viscous and elastic behavior leading to a complex stress state that may change the dynamics of the interface deformation and breakup. We extend the available asymptotic model based on lubrication approximation to include elastic interfacial stress. Drop breakup time is determined as a function of the capillary geometry and liquid properties, including the interfacial elastic modulus. Results show that the interfacial elasticity has a stabilizing effect by slowing down the growth of the liquid collar, leading to a larger break-up time. This stabilizing effect has been observed experimentally in different, but related flows [Alvarado et al., “Interfacial visco-elasticity of crude oil-brine: An alternative EOR mechanism in smart waterflooding,” in SPE-169127 Improved Oil Recovery Symposium (Society of Petroleum Engineers, 2014)].
High-resolution error detection in the capture process of a single-electron pump
Authors: Giblin S. P. , See P. , Petrie A. , Janssen T. J. B. M. , Farrer I. , Griffiths J. P. , Jones G. A. C. , Ritchie D. A. , Kataoka M.
Published: January 2016

The dynamic capture of electrons in a semiconductor quantum dot (QD) by raising a potential barrier is a crucial stage in metrological quantized charge pumping. In this work, we use a quantum point contact (QPC) charge sensor to study errors in the electron capture process of a QD formed in a GaAs heterostructure. Using a two-step measurement protocol to compensate for 1/f noise in the QPC current, and repeating the protocol more than 106 times, we are able to resolve errors with probabilities of order 10−6. For the studied sample, one-electron capture is affected by errors in ∼30 out of every million cycles, while two-electron capture was performed more than 106 times with only one error. For errors in one-electron capture, we detect both failure to capture an electron and capture of two electrons. Electron counting measurements are a valuable tool for investigating non-equilibrium charge capture dynamics, and necessary for validating the metrological accuracy of semiconductor electron pumps.
Calibration procedures for quantitative multiple wavelengths reflectance microscopy
Authors: Fedala Yasmina , Munteanu Sorin , Kanoufi Frédéric , Tessier Gilles , Roger Jean Paul , Wu Chang , Amiot Fabien
Published: January 2016

In order to characterize surface chemo-mechanical phenomena driving micro-electro-mechanical systems (MEMSs) behavior, it has been previously proposed to use reflected intensity fields obtained from a standard microscope for different illumination wavelengths. Wavelength-dependent and -independent reflectivity fields are obtained from these images, provided the relative reflectance sensitivities ratio can be identified. This contribution focuses on the necessary calibration procedures and mathematical methods allowing for a quantitative conversion from a mechanically induced reflectivity field to a surface rotation field, therefore paving the way for a quantitative mechanical analysis of MEMS under chemical loading.
Instability of stationary two-dimensional mixed convection across a vertical porous layer
Authors: Barletta Antonio
Published: January 2016

The two-dimensional and stationary mixed convection in a vertical porous layer is studied. This mixed convection flow is caused by the pressure and temperature difference between the parallel boundaries of the porous layer. In the limiting case where the boundary pressure difference is zero, the two-dimensional flow actually becomes the one-dimensional conduction regime of natural convection. On the other hand, when the boundary temperature difference tends to zero, the two-dimensional flow becomes a simple uniform horizontal through flow. The linear stability of the basic two-dimensional mixed convection is analysed. The growth rate and the angular frequency of the perturbations are evaluated numerically. The neutral stability curves are obtained by plotting the Rayleigh number versus the wave number, for different values of the Péclet number associated with the boundary pressure difference. The effect of the dynamic boundary conditions on the onset of the convective instability is discussed.
Sensitivity and noise of micro-Hall magnetic sensors based on InGaAs quantum wells
Authors: Chenaud B. , Segovia-Mera A. , Delgard A. , Feltin N. , Hoffmann A. , Pascal F. , Zawadzki W. , Mailly D. , Chaubet C.
Published: January 2016

We study the room-temperature performance of micro-Hall magnetic sensors based on pseudomorphic InGaAs quantum wells. Active areas of our sensors range from 1 to 80 μm. We focus on the smallest detectable magnetic fields in small sensors and perform a systematic study of noise at room temperature in the frequency range between 1 Hz and 100 kHz. Our data are interpreted by the mobility fluctuation model. The Hooge parameter is determined for the applied technology. We show that, independently of the experimental frequency, the ratio of sensitivity to noise is proportional to characteristic length of the sensor. The resolution of 1 mG/Hz is achievable in a 3μm sensor at room temperature.
Non-destructive measurement of in-operando lithium concentration in batteries via x-ray Compton scattering
Authors: Suzuki K. , Barbiellini B. , Orikasa Y. , Kaprzyk S. , Itou M. , Yamamoto K. , Wang Yung Jui , Hafiz H. , Uchimoto Y. , Bansil A. , Sakurai Y. , Sakurai H.
Published: January 2016

Non-destructive determination of lithium distribution in a working battery is key for addressing both efficiency and safety issues. Although various techniques have been developed to map the lithium distribution in electrodes, these methods are mostly applicable to test cells. Here, we propose the use of high-energy x-ray Compton scattering spectroscopy to measure the local lithium concentration in closed electrochemical cells. A combination of experimental measurements and parallel first-principles computations is used to show that the shape parameter S of the Compton profile is linearly proportional to lithium concentration and thus provides a viable descriptor for this important quantity. The merits and applicability of our method are demonstrated with illustrative examples of LixMn2O4 cathodes and a working commercial lithium coin battery CR2032.
A cryogenic rotation stage with a large clear aperture for the half-wave plates in the Spider instrument
Authors: Bryan Sean , Ade Peter , Amiri Mandana , Benton Steven , Bihary Richard , Bock James , Bond J. Richard , Chiang H. Cynthia , Contaldi Carlo , Crill Brendan , Dore Olivier , Elder Benjamin , Filippini Jeffrey , Fraisse Aurelien , Gambrel Anne , Gandilo Natalie , Gudmundsson Jon , Hasselfield Matthew , Halpern Mark , Hilton Gene , Holmes Warren , Hristov Viktor , Irwin Kent , Jones William , Kermish Zigmund , Lawrie Craig , MacTavish Carrie , Mason Peter , Megerian Krikor , Moncelsi Lorenzo , Montroy Thomas , Morford Tracy , Nagy Johanna , Netterfield C. Barth , Padilla Ivan , Rahlin Alexandra S. , Reintsema Carl , Riley Daniel C. , Ruhl John , Runyan Marcus , Saliwanchik Benjamin , Shariff Jamil , Soler Juan , Trangsrud Amy , Tucker Carole , Tucker Rebecca , Turner Anthony , Wen Shyang , Wiebe Donald , Young Edward
Published: January 2016

We describe the cryogenic half-wave plate rotation mechanisms built for and used in Spider, a polarization-sensitive balloon-borne telescope array that observed the cosmic microwave background at 95 GHz and 150 GHz during a stratospheric balloon flight from Antarctica in January 2015. The mechanisms operate at liquid helium temperature in flight. A three-point contact design keeps the mechanical bearings relatively small but allows for a large (305 mm) diameter clear aperture. A worm gear driven by a cryogenic stepper motor allows for precise positioning and prevents undesired rotation when the motors are depowered. A custom-built optical encoder system monitors the bearing angle to an absolute accuracy of ±0.1∘. The system performed well in Spider during its successful 16 day flight.
Study of ion-ion plasma formation in negative ion sources by a three-dimensional in real space and three-dimensional in velocity space particle in cell model
Authors: Nishioka S. , Goto I. , Miyamoto K. , Hatayama A. , Fukano A.
Published: January 2016

Recently, in large-scale hydrogen negative ion sources, the experimental results have shown that ion-ion plasma is formed in the vicinity of the extraction hole under the surface negative ion production case. The purpose of this paper is to clarify the mechanism of the ion-ion plasma formation by our three dimensional particle-in-cell simulation. In the present model, the electron loss along the magnetic filter field is taken into account by the “τ///τ⊥ model.” The simulation results show that the ion-ion plasma formation is due to the electron loss along the magnetic filter field. Moreover, the potential profile for the ion-ion plasma case has been looked into carefully in order to discuss the ion-ion plasma formation. Our present results show that the potential drop of the virtual cathode in front of the plasma grid is large when the ion-ion plasma is formed. This tendency has been explained by a relationship between the virtual cathode depth and the net particle flux density at the virtual cathode.
Voltage band based improved particle swarm optimization technique for maximum power point tracking in solar photovoltaic system
Authors: Sudhakar Babu T. , Sangeetha K. , Rajasekar N.
Published: January 2016

The extraction of maximum power from solar photovoltaic (PV) using Maximum Power Point Tracking (MPPT) methods is a promising research area in the recent past. Many methods including conventional methods, such as Hill Climbing and Incremental Conductance, and methods based on neural network, Fuzzy logic and bio-inspired algorithms, were proposed for MPPT application. However, all these methods suffer from drawbacks such as slower convergence, reduced power output, predominant steady state oscillations, larger memory requirement, and complex structure. Hence, in this paper an attempt is made to enhance existing Particle Swarm Optimization technique by emphasizing proper initial value selection. The key features of this method include the ability to track the global peak power accurately under partial shading conditions with almost zero steady state oscillations, faster dynamic response, and easy implementation. Simulations are carried out for different shading patterns and the results obtained are compared with existing methods. Further, simulation results are validated via experimental values.
Stabilization of sawteeth with third harmonic deuterium ICRF-accelerated beam in JET plasmas
Authors: Girardo Jean-Baptiste , Sharapov Sergei , Boom Jurrian , Dumont Rémi , Eriksson Jacob , Fitzgerald Michael , Garbet Xavier , Hawkes Nick , Kiptily Vasily , Lupelli Ivan , Mantsinen Mervi , Sarazin Yanick , Schneider Mireille ,   JET Contributors
Published: January 2016

Sawtooth stabilisation by fast ions is investigated in deuterium (D) and D-helium 3 (He3) plasmas of JET heated by deuterium Neutral Beam Injection combined in synergy with Ion Cyclotron Resonance Heating (ICRH) applied on-axis at 3rd beam cyclotron harmonic. A very significant increase in the sawtooth period is observed, caused by the ICRH-acceleration of the beam ions born at 100 keV to the MeV energy range. Four representative sawteeth from four different discharges are compared with Porcelli's model. In two discharges, the sawtooth crash appears to be triggered by core-localized Toroidal Alfvén Eigenmodes inside the q = 1 surface (also called “tornado” modes) which expel the fast ions from within the q = 1 surface, over time scales comparable with the sawtooth period. Two other discharges did not exhibit fast ion-driven instabilities in the plasma core, and no degradation of fast ion confinement was found in both modelling and direct measurements of fast ion profile with the neutron camera. The developed sawtooth scenario without fast ion-driven instabilities in the plasma core is of high interest for the burning plasmas. Possible causes of the sawtooth crashes on JET are discussed.
Maximum time-dependent space-charge limited diode currents
Authors: Griswold M. E. , Fisch N. J.
Published: January 2016

Recent papers claim that a one dimensional (1D) diode with a time-varying voltage drop can transmit current densities that exceed the Child-Langmuir (CL) limit on average, apparently contradicting a previous conjecture that there is a hard limit on the average current density across any 1D diode, as t → ∞, that is equal to the CL limit. However, these claims rest on a different definition of the CL limit, namely, a comparison between the time-averaged diode current and the adiabatic average of the expression for the stationary CL limit. If the current were considered as a function of the maximum applied voltage, rather than the average applied voltage, then the original conjecture would not have been refuted.