bluuebunny/crossref_metadata_2025 huggingface dataset:
Gold-catalyzed allene cycloisomerization for pyrrole synthesis: towards highly fluorinated BODIPY dyes
Authors: Lempke Linda , Fischer Tobias , Bell Jérémy , Kraus Werner , Rurack Knut , Krause Norbert
Published: February 2015

A novel synthetic strategy toward highly fluorinated BODIPY dyes with exceptional photostabilities relying on sustainable gold catalysis has been developed.
Using click chemistry to dial up the modulus of doubly crosslinked microgels through precise control of microgel building block functionalisation
Authors: Farley Robert , Halacheva Silvia , Bramhill Jane , Saunders Brian R.
Published: February 2015

Vinyl functionalisation of poly(2-vinylpyridine-propargylacrylate) microgels via click chemistry gives hydrogels of inter-linked microgels with tuneable modulus values.
Crystal structure determination, spectroscopic characterization and biological profile of a tailored ionic molecular entity, Sn(iv) iminodiacetic acid–piperazinediium conjugate: in vitro DNA/RNA binding studies, Topo I inhibition activity, cytotoxic and systemic toxicity studies
Authors: Arjmand Farukh , Yousuf Imtiyaz , Zaidi Yusra , Toupet Loic
Published: February 2015

In vitro DNA/RNA binding studies and cytotoxic activity of complex 1 along with its in vivo systemic toxicity assay.
Cross-linking of poly(vinyl alcohol) with N,N′-methylene bisacrylamide via a radical reaction to prepare pervaporation membranes
Authors: Li Junjun , Zhang Lin , Gu Jin , Sun Yuping , Ji Xiaosheng
Published: February 2015

To retain the hydroxyl group of PVA, ammonium persulfate (APS) was used to initiate the polymerization of hydrogen on the PVA chain. Instead of hydroxyl-based cross-linking, the generated PVA macromolecule radicals were cross-linked with MBA to prepare PVA membranes.
Influence of porphyrin meso-attached substituent on the SMM behavior of dysprosium(iii) double-deckers with mixed tetrapyrrole ligands
Authors: Cao Wei , Zhang Yuehong , Wang Hailong , Wang Kang , Jiang Jianzhuang
Published: February 2015

Studies for mixed (phthalocyaninato)(porphyrinato) dysprosium(iii) double-decker SMMs reveal the influence of substituent of the porphyrin ligand on the magnetic properties.
Molecularly imprinted polymer nanospheres based on Mn-doped ZnS QDs via precipitation polymerization for room-temperature phosphorescence probing of 2,6-dichlorophenol
Authors: Wei Xiao , Zhou Zhiping , Hao Tongfan , Li Hongji , Yan Yongsheng
Published: February 2015

A novel MIPs-based RTP QDs with molecular recognition ability for 2,6-dichlorophenol was successfully synthesized via precipitation polymerization.
Molar ratios of therapeutic water-soluble phenothiazine·water-insoluble phospholipid adducts reveal a Fibonacci correlation and a putative link for structure–activity relationships
Authors: Keyzer Hendrik , Fey Stephen J. , Thornton Barry , Kristiansen Jette E.
Published: February 2015

The fact that non-antibiotics can sensitise microorganisms for antibiotic treatment suggests that these molecules have valuable potential to treat multiple drug resistance.
Structural characteristics of a cooperatively rearranging region during the glass transition of a polymer system
Authors: Nie Yijing , Ye Xubo , Zhou Zhiping , Hao Tongfan , Yang Wenming , Lu Haifeng
Published: February 2015

Local ordered structures are formed during glass transition. These local orders preferred to move cooperatively during relaxation. In other words, the cooperatively rearranging regions contained some local order.
Amphiphilic porous polyhedral oligomeric silsesquioxanes (POSS) incorporated polyoxometalate-paired polymeric hybrids: interfacial catalysts for epoxidation reactions
Authors: Leng Yan , Zhao Jiwei , Jiang Pingping , Wang Jun
Published: February 2015

Amphiphilic porous POSS incorporated POM-paired polymeric hybrids were demonstrated to be highly efficient interfacial catalysts for epoxidation of alkenes with H2O2.
Cooperative breakups induced by drop-to-drop interactions in one-dimensional flows of drops against micro-obstacles
Authors: Schmit Alexandre , Salkin Louis , Courbin Laurent , Panizza Pascal
Published: February 2015

We present a model describing the complex breakup dynamics of one-dimensional trains of drops against rectangular micro-obstacles.
Enhancing the stability of spontaneously self-assembled vesicles – the effect of polymer architecture
Authors: Bressel Katharina , Gradzielski Michael
Published: February 2015

The size and stability of spontaneously forming vesicles can be controlledviathere pathway of formation by amphiphilic copolymers.
Molybdenum carbide nanocrystal embedded N-doped carbon nanotubes as electrocatalysts for hydrogen generation
Authors: Zhang Kai , Zhao Yang , Fu Diyu , Chen Yujin
Published: February 2015

Highly conductive N-doped carbon nanotubes embedded with molybdenum carbide nanocrystals with a size less than 3 nm exhibit superior activity for the hydrogen evolution reaction, including small overpotential, large cathodic current density and high exchange current density.
Hybrid fullerene conjugates as vectors for DNA cell-delivery
Authors: Uritu Cristina M. , Varganici Cristian D. , Ursu Laura , Coroaba Adina , Nicolescu Alina , Dascalu Andrei I. , Peptanariu Dragos , Stan Daniela , Constantinescu Cristina A. , Simion Viorel , Calin Manuela , Maier Stelian S. , Pinteala Mariana , Barboiu Mihail
Published: February 2015

C60-PEI and C60-PEG-PEI as efficient binders of dsDNA, with good transfection up to 25%, high cytocompatibility and cell proliferation up to 200%.
Eu3+@PMO: synthesis, characterization and luminescence properties
Authors: Esquivel Dolores , Kaczmarek Anna M. , Jiménez-Sanchidrián César , Van Deun Rik , Romero-Salguero Francisco J. , Van Der Voort Pascal
Published: February 2015

Two novel organic–inorganic luminescent hybrid materials have been obtained by linking of Eu3+compounds to an ethene-PMO functionalized with dipyridyl-dihydropyridazine.
Towards the development of mechanism-based biomarkers to diagnose drug hypersensitivity
Authors: Duran-Figueroa N. , Badillo-Corona J. A. , Naisbitt D. J. , Castrejon-Flores J. L.
Published: February 2015

T-cells are activated by different mechanisms in the presence of drugs, metabolites or haptens, and they release several molecules that can be used in the diagnosis of drug hypersensitivity.
Functionalities and architectures of coordination polymers with multi-dimensionalities via transition metal–dicarboxylate ligands
Authors: Cao Xinyu , Li Ling , Li Changxia , Lv Lei , Huang Rudan
Published: February 2015

Five coordination polymers based on the flexible H2dpd ligand and different metal salts have been synthesised. The configuration of the ligand and the reaction temperature have important effects on the final structures.
Tuning the electronic properties of Ti–MoS2 contacts through introducing vacancies in monolayer MoS2
Authors: Feng Li-ping , Su Jie , Li Da-peng , Liu Zheng-tang
Published: February 2015

Ti–MoS2 top contacts with intrinsic vacancies in monolayer MoS2 show novel electronic structures and electronic properties.
Correlation of crystal structure and microwave dielectric properties of Nd1.02(Nb1−xTax)0.988O4 ceramic
Authors: Zhang Ping , Zhao Yonggui , Liu Jian , Song Zhenkun , Xiao Mi , Wang Xiuyu
Published: February 2015

We discussed the correlation of crystal structure and microwave dielectric properties for NdNbO4 which forms a monoclinic fergusonite structure.
Reactions of iodine-nitrene reagents with boranes
Authors: Postle Shawn , Stephan Douglas W.
Published: February 2015

Reactions of the boranes (C6F5)2BR (R = C6F5, Ph, H) with the nitrene-iodine reagents XC6H4SO2NIPh, X = Me, Cl and MeSO2NIPh effect the insertion of nitrene into the B–C and B–H bonds affording the species (C6F5)2BN(SO2C6H4X)R (X = Me, R = C6F51, Ph 3, H, 4, X = Cl, 5, X = NO2, 7) and (C6F5)2BN(SO2Me)H 6).
Hierarchical control of coherent gene clusters defines the molecular mechanisms of glioblastoma
Authors: Tsigelny Igor F. , Kouznetsova Valentina L. , Jiang Pengfei , Pingle Sandeep C. , Kesari Santosh
Published: February 2015

We report an integrative networks-based analysis to identify a system of coherent gene modules in primary and secondary glioblastoma.
Inhibition of insulin amyloid fibrillization by glyco-acridines: anin vitroandin silicostudy
Authors: Van Vuong Quan , Bednarikova Zuzana , Antosova Andrea , Huy Pham Dinh Quoc , Siposova Katarina , Tuan Nguyen Anh , Li Mai Suan , Gazova Zuzana
Published: February 2015

The structure of glyco-acridines determines their impact on insulin amyloid aggregation and newly introduced geometrical descriptors allow us to distinguish different binding affinities.
Hydrogen bonding promoting the controlled radical polymerization of 2-vinyl pyridine: supramonomer for better control
Authors: Wu Huaqiao , Wan Yingbo , Wang Wenxiang , Wang Yong , Zhou Nianchen , Zhang Wei , Li Xiaohong , Zhang Zhengbiao , Zhu Xiulin
Published: February 2015

Hydrogen bonding can promote the controlled radical polymerization of 2-vinyl pyridine, and the monomer activating effect is elucidated for the first time.
Optimization of a liquid chromatography-tandem mass spectrometry method for the quantification of traces of taxanes in a Corylus avellana cell suspension medium
Authors: Gallego Ana , Jáuregui Olga , Moyano Elisabeth , Palazón Javier , Casals Isidre , Bonfill Mercedes
Published: February 2015

We developed a reliable HPLC-MS/MS method to quantify five of the most commercially important taxanes in a C. avellana cell suspension medium. Its linearity, intra- and inter-day precision, recovery, accuracy, LOD/LOQ and matrix effect were evaluated.
A photoluminescent biosensor based on long-range self-assembled DNA cascades and upconversion nanoparticles for the detection of breast cancer-associated circulating microRNA in serum samples
Authors: Lan Jianming , Wen Fadi , Fu Fangmeng , Zhang Xi , Cai Shuxian , Liu Zhijing , Wu Dongzhi , Li Chunyan , Chen JingHua , Wang Chuan
Published: February 2015

A photoluminescent biosensor was developed for the detection of microRNA (miRNA) combined signal amplification of long-range self-assembled DNA cascades with upconversion nanoparticles.
Correction: Conformational transition of a non-associative fluorinated amphiphile in aqueous solution
Authors: Taraban Marc B. , Yu Li , Feng Yue , Jouravleva Elena V. , Anisimov Mikhail A. , Jiang Zhong-Xing , Yu Y. Bruce
Published: February 2015

Correction for ‘Conformational transition of a non-associative fluorinated amphiphile in aqueous solution’ by Marc B. Taraban et al., RSC Adv., 2014, 4, 54565–54575.
Non-covalent interaction cooperatively induced stretchy, tough and stimuli-responsive polyurethane–urea supramolecular (PUUS) hydrogels
Authors: Cui Yulin , Tan Mei , Zhu Aidi , Guo Mingyu
Published: February 2015

Hydrogen-bonding and hydrophobic effect cooperatively induced stretchy, tough and stimuli-responsive polyurethane–urea supramolecular hydrogels were easily prepared and studied in detail.
Wnt3a signal pathways activate MyoD expression by targeting cis-elements inside and outside its distal enhancer
Authors: Pan Yu Chih , Wang Xiao Wen , Teng Han Feng , Wu Yi Ju , Chang Hsuan Chia , Chen Shen Liang
Published: February 2015

Wnt proteins are secreted cytokines and several Wnts are expressed in the developing somites and surrounding tissues. Without proper Wnt stimulation, the organization of the dermomyotome and myotome can become defective. These Wnt signals received by somitic cells can lead to activation of Pax3/Pax7 and myogenic regulatory factors (MRFs), especially Myf5 and MyoD. However, it is currently unknown whether Wnts activate Myf5 and MyoD through direct targeting of their cis-regulatory elements or via indirect pathways. To clarify this issue, in the present study, we tested the regulation of MyoD cis-regulatory elements by Wnt3a secreted from human embryonic kidney (HEK)-293T cells. We found that Wnt3a activated the MyoD proximal 6.0k promoter (P6P) only marginally, but highly enhanced the activity of the composite P6P plus distal enhancer (DE) reporter through canonical and non-canonical pathways. Further screening of the intervening fragments between the DE and the P6P identified a strong Wnt-response element (WRE) in the upstream −8 to −9k region (L fragment) that acted independently of the DE, but was dependent on the P6P. Deletion of a Pax3/Pax7-targeted site in the L fragment significantly reduced its response to Wnt3a, implying that Wnt3a activates the L fragment partially through Pax3/Pax7 action. Binding of β-catenin and Pax7 to their target sites in the DE and the L fragment respectively was also demonstrated by ChIP. These observations demonstrated the first time that Wnt3a can directly activate MyoD expression through targeting cis-elements in the DE and the L fragment.
Individual Differences in Behavioral and Electrophysiological Measures of Binaural Processing Across the Adult Life Span
Authors: Roup Christina M. , Leigh Elizabeth D.
Published: February 2015

Purpose

The purpose of the present study was to examine individual differences in binaural processing across the adult life span.

Method

Sixty listeners (aged 23–80 years) with symmetrical hearing were tested. Binaural behavioral processing was measured by the Words-in-Noise Test, the 500-Hz masking level difference, and the Dichotic Digit Test. Electrophysiologic responses were assessed by the auditory middle latency response binaural interaction component.

Results

No correlations among binaural measures were found. Age accounted for the greatest amount of variability in speech-in-noise performance. Age was significantly correlated with the Words-in-Noise Test binaural advantage and dichotic ear advantage. Partial correlations, however, revealed that this was an effect of hearing status rather than age per se. Inspection of individual results revealed that 20% of listeners demonstrated reduced binaural performance for at least 2 of the binaural measures.

Conclusions

The lack of significant correlations among variables suggests that each is an important measurement of binaural abilities. For some listeners, binaural processing was abnormal, reflecting a binaural processing deficit not identified by monaural audiologic tests. The inclusion of a binaural test battery in the audiologic evaluation is supported given that these listeners may benefit from alternative forms of audiologic rehabilitation.
Modeling the Influence of Acoustic Coupling of Hearing Aids on FM Signal-to-Noise Ratio
Authors: Norrix Linda W. , Van Tasell Dianne , Ross Jessie , Harris Frances P. , Dean James
Published: February 2015

Purpose

A model was developed to examine variables that influence signal-to-noise ratio (SNR) at the tympanic membrane (TM) when using a hearing aid (HA) and frequency modulated (FM) system. The model was used to explore how HA coupling influences SNR.

Method

To generate the model, HA output was measured in a coupler. Known coupler to real-ear transformations and known values for vent (gain) loss as a function of coupling were also used. The model was verified by measuring sound pressure level (SPL) at the TM in 6 ears.

Results

The model predicts similar overall SNRs at the TM regardless of coupling method when HA and FM microphones are active. The primary difference in SNR is in the low frequencies and depends on the amount of low frequency insertion gain and the noise levels at the HA and FM microphones.

Conclusions

A model was developed to explore how complex variables contribute to SNR at the TM. One variable, HA coupling, is predicted to have only a minimal effect on SNR at the TM when there is HA gain. Further studies will be needed to assess the real-world effectiveness of an FM system coupled to an open- versus closed-fit HA.
Input/output selection for wide‐area power oscillation damper of hybrid multi‐terminal high‐voltage direct current to connect remotely located renewable energy resources
Authors: Nguyen Mai Huong , Saha Tapan Kumar , Eghbal Mehdi
Published: February 2015

A hybrid multi‐terminal HVDC (MTDC) scheme combines line commutated converter and voltage source converter technologies for HVDC transmission system. This study presents a comprehensive design of wide‐area power oscillation damper (POD) controller for the hybrid MTDC system. The process consists of input/output selection and parameter tuning for the POD of the hybrid MTDC based on the linearised black‐box model. The objective is to choose an effective control loop to damp the critical mode, which does not have negative impacts on the other modes in the system. For this purpose, a new index, named relative joint interaction index, is proposed for the input/output selection. Afterward, the parameter of POD is tuned using residue‐based phase compensation technique because of its practical application. Finally, non‐linear simulations are also carried out to verify the effectiveness of the designed POD in different loading conditions.
Optimal unified power flow controller application to enhance total transfer capability
Authors: Rajabi‐Ghahnavieh Abbas , Fotuhi‐Firuzabad Mahmud , Othman Muhammad
Published: February 2015

For a power transfer path, total transfer capability (TTC) represents maximum power that can be transferred over the transmission system. Unified power flow controller (UPFC) is a device that can be used to increase in TTC. This study presents a new method for optimal UPFC application to minimise power loss while enhancing TTC. Based on UPFC injection model, the solution region of UPFC parameters is first found using the proposed method to maximise TTC. It then searches the solution region to find optimal UPFC control mode and setting to minimise system power loss. The proposed method is applied to the IEEE‐Reliability Test System and the UPFC application impact are evaluated. Comparative studies are conducted between the TTC results obtained by the proposed method with those obtained using the existing approaches.
Model order reduction for transient simulation of active distribution networks
Authors: Wang Chengshan , Yu Hao , Li Peng , Wu Jianzhong , Ding Chengdi
Published: February 2015

With the increasing penetration of distributed generation, distribution networks are evolving from passive to active. New transient simulation methods are required to study the detailed dynamic characteristics of large‐scale active distribution networks. A model order reduction method based on Krylov subspace theory is introduced in this study to reduce the overall model scale of active distribution networks for transient simulations. A modified state‐space model of linear distribution networks is developed to replace the conventional models for improvement in model reduction efficiency, while guaranteeing the passivity and stability of the reduced models. The proposed model order reduction method is validated with the IEEE 123‐node test network. The results prove that the proposed method is effective for different applications to improve the simulation efficiency of large‐scale active distribution networks.
Adaptive backstepping droop controller design for multi‐terminal high‐voltage direct current systems
Authors: Zhao Xiaodong , Li Kang
Published: February 2015

Wind power is one of the most developed renewable energy resources worldwide. To integrate offshore wind farms to onshore grids, the high‐voltage direct current (HVDC) transmission cables interfaced with voltage source converters (VSCs) are considered to be a better solution than conventional approaches. Proper DC voltage indicates successive power transfer. To connect more than one onshore grid, the DC voltage droop control is one of the most popular methods to share the control burden between different terminals. However, the challenges are that small droop gains will cause voltage deviations, while higher droop gain settings will cause large oscillations. This study aims to enhance the performance of the traditional droop controller by considering the DC cable dynamics. Based on the backstepping control concept, DC cables are modelled with a series of capacitors and inductors. The final droop control law is deduced step‐by‐step from the original remote side. At each step the control error from the previous step is considered. Simulation results show that both the voltage deviations and oscillations can be effectively reduced using the proposed method. Further, power sharing between different terminals can be effectively simplified such that it correlates linearly with the droop gains, thus enabling simple yet accurate system operation and control.
Hybrid method for power system state estimation
Authors: Risso Mariano , Rubiales Aldo Jose , Lotito Pablo Andres
Published: February 2015

State estimation in power systems is classically based on the weighted least squares method. Recently, different extensions of Kalman filters have been proposed. Among them, the ‘unscented’ Kalman filter (UKF) improves the results of weighted least squares methods, when there are small changes in the system, as it considers the history of the state. The novel algorithm presented in this work combines the best of both approaches. To perform this task a new index is defined to allow the algorithm to choose in real time, and for each iteration, between a static or a dynamic estimator. This combination allows overcoming the anomalies observed when the UKF faces abrupt variations of the system state and also the lack of observability that weighted least squares could present. The proposed methodology was tested with three test cases outperforming the previously mentioned algorithms.
Dual frequency inverter configuration for multiple‐load induction cooking application
Authors: Papani Sharath Kumar , Neti Vishwanathan , Murthy Bhagwan K.
Published: February 2015

Induction cooking application with multiple loads powered by suitable power converters and appropriate control technique needs attention. This study proposes dual frequency operated full‐bridge inverter for multiple‐load induction cooking. This inverter simultaneously powers two series resonant circuits. Each series resonant circuit is for one induction cooking load. This technique provides constant switching frequency operation for individual loads with asymmetrical duty cycle control. Output power of each load is independently controlled. The proposed inverter configuration and control technique is simulated and experimentally tested for two loads. Simulation and experimental results are in good agreement. This technique can be extended to more than two loads.
Transient interference and noise suppression by complex matrix recovery with Hankel constraint
Authors: Li Mao , He Zishu , Yang Shaowei
Published: February 2015

The transient interference can dramatically degrade the performance of over‐the‐horizon radar. Traditional interference suppression methods need to detect the interferences, excise the corrupted data and reconstruct the data via interpolation. The detection is the precondition of the subsequent steps. In the cases where the interferences are weak, the traditional methods cannot efficiently detect and suppress them. In this study, the authors propose a novel interference suppression method based on matrix recovery. The proposed method formulates the interference suppression as a matrix recovery problem and solves the convex optimisation problem via the augmented Lagrange multiplier method. Unlike the traditional methods, the proposed method does not need the detection, excising and interpolation steps. The proposed algorithm can suppress not only the interferences including the weak and strong ones but also the noise. Experimental results have demonstrated the effectiveness of the proposed method.
Optically probing Al—O and O—H vibrations to characterize water adsorption and surface reconstruction on α-alumina: An experimental and theoretical study
Authors: Tong Yujin , Wirth Jonas , Kirsch Harald , Wolf Martin , Saalfrank Peter , Campen R. Kramer
Published: February 2015

Oxide/water interfaces are ubiquitous in a wide variety of applications and the environment. Despite this ubiquity, and attendant decades of study, gaining molecular level insight into water/oxide interaction has proven challenging. In part, this challenge springs from a lack of tools to concurrently characterize changes in surface structure (i.e., water/oxide interaction from the perspective of the solid) and O—H population and local environment (i.e., water/oxide interaction from the water perspective). Here, we demonstrate the application of surface specific vibrational spectroscopy to the characterization of the interaction of the paradigmatic α-Al2O3(0001) surface and water. By probing both the interfacial Al—O (surface phonon) and O—H spectral response, we characterize this interaction from both perspectives. Through electronic structure calculation, we assign the interfacial Al—O response and rationalize its changes on surface dehydroxylation and reconstruction. Because our technique is all-optical and interface specific, it is equally applicable to oxide surfaces in vacuum, ambient atmospheres and at the solid/liquid interface. Application of this approach to additional alumina surfaces and other oxides thus seems likely to significantly expand our understanding of how water meets oxide surfaces and thus the wide variety of phenomena this interaction controls.
Geometric pumping induced by shear flow in dilute liquid crystalline polymer solutions
Authors: Yabunaka Shunsuke , Hayakawa Hisao
Published: February 2015

We investigate nonlinear rheology of dilute liquid crystalline polymer solutions under time dependent two-directional shear flow. We analyze the Smoluchowski equation, which describes the dynamics of the orientation of a liquid crystalline polymer, by employing technique of the full counting statistics. In the adiabatic limit, we derive the expression for time integrated currents generated by a Berry-like curvature. Using this expression, it is shown that the expectation values of the time-integrated angular velocity of a liquid crystalline polymer and the time-integrated stress tensor are generally not zero even if the time average of the shear rate is zero. The validity of the theoretical calculations is confirmed by direct numerical simulations of the Smoluchowski equation. Nonadiabatic effects are also investigated by means of simulations and it is found that the time-integrated stress tensor depends on the speed of the modulation of the shear rate if we adopt the isotropic distribution as an initial state.
The influence of oxygen adsorption on the NEXAFS and core-level XPS spectra of the C60 derivative PCBM
Authors: Brumboiu Iulia Emilia , Ericsson Leif , Hansson Rickard , Moons Ellen , Eriksson Olle , Brena Barbara
Published: February 2015

Fullerenes have been a main focus of scientific research since their discovery due to the interesting possible applications in various fields like organic photovoltaics (OPVs). In particular, the derivative [6,6]-phenyl-C60-butyric acid methyl ester (PCBM) is currently one of the most popular choices due to its higher solubility in organic solvents compared to unsubstituted C60. One of the central issues in the field of OPVs is device stability, since modules undergo deterioration (losses in efficiency, open circuit voltage, and short circuit current) during operation. In the case of fullerenes, several possibilities have been proposed, including dimerization, oxidation, and impurity related deterioration. We have studied by means of density functional theory the possibility of oxygen adsorption on the C60 molecular moiety of PCBM. The aim is to provide guidelines for near edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) measurements which can probe the presence of atomic or molecular oxygen on the fullerene cage. By analysing several configurations of PCBM with one or more adsorbed oxygen atoms, we show that a joint core level XPS and O1s NEXAFS investigation could be effectively used not only to confirm oxygen adsorption but also to pinpoint the bonding configuration and the nature of the adsorbate.
Wave propagation of phonon and phason displacement modes in quasicrystals: Determination of wave parameters
Authors: Chellappan Vinita , Gopalakrishnan S. , Mani V.
Published: February 2015

The paper presents the study of wave propagation in quasicrystals. Our interest is in the computation of the wavenumber (kn) and group speed (cg) of the phonon and phason displacement modes of one, two, and three dimensional quasicrystals. These wave parameter expressions are derived and computed using the elasto-hydrodynamic equations for quasicrystals. For the computation of the wavenumber and group speeds, we use Fourier transform approximation of the phonon and the phason displacement modes. The characteristic equations obtained are a polynomial equation of the wavenumber (kn), with frequency as a parameter. The corresponding group speeds (cg) for different frequencies are then computed from the wavenumber kn. The variation of wavenumber and group speeds with frequency is plotted for the 1-D quasicrystal, 2-D decagonal Al-Ni-Co quasicrystals, and 3-D icosahedral Al-Pd-Mn and Zn-Mg-Sc quasicrystals. From the wavenumber and group speeds plots, we obtain the cut-off frequencies for different spatial wavenumber ηm. The results show that for 1-D, 2-D, and 3-D quasicrystals, the phonon displacement modes are non-dispersive for low values of ηm and becomes dispersive for increasing values of ηm. The cut-off frequencies are not observed for very low values of ηm, whereas the cut-off frequency starts to appear with increasing ηm. The group speeds of the phason displacement modes are orders of magnitude lower than that of the phonon displacement modes, showing that the phason modes do not propagate, and they are essentially the diffusive modes. The group speeds of the phason modes are also not influenced by ηm. The group speeds for the 2-D quasicrystal at 35 kHz is also simulated numerically using Galerkin spectral finite element methods in frequency domain and is compared with the results obtained using wave propagation analysis. The effect of the phonon and phason elastic constants on the group speeds is studied using 3-D icosahedral Al-Pd-Mn and Zn-Mg-Sc quasicrystals. It is also shown that the phason elastic constants and the coupling coefficient do not affect the group speeds of the phonon displacement modes.
Experimental study of the instability of laminar flow in a tube with deformable walls
Authors: Neelamegam R. , Shankar V.
Published: February 2015

The onset of instability of laminar flow in a tube with deformable walls is studied experimentally in order to characterize how the onset is affected by the elastic (shear) modulus of the deformable wall. To this end, rectangular blocks of polydimethylsiloxane (PDMS) gels of different shear moduli are fabricated with a cylindrical hole (of diameter 1.65 mm) in which the fluid (water) flow occurs due to an imposed pressure difference. The shear moduli of the PDMS gels were in the range of 21 - 608 kPa. When fluid flows through the deformable tube, we find that the tube radius changes slowly as a function of distance along the flow, and this change is a function of Reynolds number (Re). The pressure drop between the two ends of the tube is measured, and the friction factor is calculated from this pressure drop. The friction factor vs. Re data shows that the expected laminar flow relation (f = 64/Re) for flow in a rigid tube is seen in a deformable tube at lower Re, but there is a deviation from this relation at Re < 2000. We identify the Re at which the deviation occurs as the Reynolds number at which the laminar flow in the deformable tube becomes unstable. This transition Reynolds number is as low as 500 for the 21 kPa PDMS gel, the softest gel studied in this work, and this value is much lower than the critical Reynolds number (∼2000) for transition in a rigid tube. The onset of the transition is also independently corroborated using a dye-stream visualization method, and the transition Reynolds number obtained with this method agrees well with the Reynolds number at which there is a deviation in the friction-factor data from the laminar relation. This transition in a deformable tube which happens at Reynolds number much lower than 2000 could be potentially exploited in improving mixing in microscale devices.
Penn gap rule in phase-change memory materials: No clear evidence for resonance bonds
Authors: Shimakawa K. , Střižik L. , Wagner T. , Frumar M.
Published: February 2015

Although a proposal of resonance bonds in crystalline phase-change materials based on the GeSbTe system has been provided, we do not find any clear evidence in favor of the proposal. The ellipsometric study demonstrates that a change in the high frequency dielectric constant ε∞ between the amorphous and crystalline phases is only scaled by the average bandgap (the Penn gap rule). Even for a pure antimony film, regarded as a prototype resonance bonding material, ε∞ was found to follow the Penn gap rule. Experimentally, we did not find any evidence of a significant change in the optical transition matrix element during the phase change, which is necessary to support the idea of resonance bonds.
Temperature controlled motion of an antiferromagnet- ferromagnet interface within a dopant-graded FeRh epilayer
Authors: Le Graët C. , Charlton T. R. , McLaren M. , Loving M. , Morley S. A. , Kinane C. J. , Brydson R. M. D. , Lewis L. H. , Langridge S. , Marrows C. H.
Published: February 2015

Chemically ordered B2 FeRh exhibits a remarkable antiferromagnetic-ferromagnetic phase transition that is first order. It thus shows phase coexistence, usually by proceeding though nucleation at random defect sites followed by propagation of phase boundary domain walls. The transition occurs at a temperature that can be varied by doping other metals onto the Rh site. We have taken advantage of this to yield control over the transition process by preparing an epilayer with oppositely directed doping gradients of Pd and Ir throughout its height, yielding a gradual transition that occurs between 350 K and 500 K. As the sample is heated, a horizontal antiferromagnetic-ferromagnetic phase boundary domain wall moves gradually up through the layer, its position controlled by the temperature. This mobile magnetic domain wall affects the magnetisation and resistivity of the layer in a way that can be controlled, and hence exploited, for novel device applications.
Inverse scattering problem and generalized optical theorem
Authors: Takayanagi Kazuo , Oishi Mariko
Published: February 2015

We present a novel solution to the inverse scattering problem. Our solution is based on a generalization of the optical theorem, and applies directly in three dimensional space. First, we derive a necessary and sufficient condition for a half-on-shell T-matrix to be physically acceptable, which turns out to be a generalization of the optical theorem. Second, we show that the inverse scattering problem, which inquires underlying potential for a given on-shell T-matrix (scattering amplitude), can be solved by looking for a half-on-shell T-matrix that satisfies the generalized optical theorem with the given on-shell T-matrix being the boundary condition. At the end, we demonstrate that the present theory works nicely using simple systems.
Superlinear generation of exciton and related paramagnetism induced by forward current in a diamond p-i-n junction
Authors: Natori Kenji
Published: February 2015

The concentration of excitons generated in a high-quality diamond p-i-n junction is investigated considering the forward current characteristics of the junction. As the forward current in the junction increases, the exciton concentration increases superlinearly, contrary to the linear increases of the electron and hole concentration. This tendency suggests a superlinear increase in emission intensity due to exciton recombination. The increase rate is more radical than quadratic, in accordance with the observed increase of the integrated intensity of free exciton emission. To estimate the concentration of triplet excitons generated in the p-i-n junction, observation of the paramagnetism due to the exciton spin moment is proposed. The magnetic susceptibility superlinearly increases with the increase in the forward current, unlike any other magnetic property of the device.
Note: Ultra-stable digitally controlled oven
Authors: Vorobyev N. , Imbaud J. , Abbe P. , Sthal F.
Published: February 2015

This paper describes design and characterization of a digitally controlled double oven system. This allows setting the turnover point of crystal oscillators automatically. Developed for metrological purposes of active phase noise measurements, this type of thermostat with a crystal oscillator is an ultra-stable digitally controlled oven crystal oscillator.
Reentrant spin glass ordering in an Fe-based bulk metallic glass
Authors: Luo Qiang , Shen Jun
Published: February 2015

We report the results of the complex susceptibility, temperature, and field dependence of DC magnetization and the nonequilibrium dynamics of a bulk metallic glass Fe40Co8Cr15Mo14C15B6Er2. Solid indication of the coexistence of reentrant spin glass (SG) and ferromagnetic orderings is determined from both DC magnetization and AC susceptibility under different DC fields. Dynamics scaling of AC susceptibility indicates critical slowing down to a reentrant SG state with a static transition temperature Ts = ∼17.8 K and a dynamic exponent zv = ∼7.3. The SG nature is further corroborated from chaos and memory effects, magnetic hysteresis, and aging behavior. We discuss the results in terms of the competition among random magnetic anisotropy and exchange interactions and compare them with simulation predictions.
Coupling polariton quantum boxes in sub-wavelength grating microcavities
Authors: Zhang Bo , Brodbeck Sebastian , Wang Zhaorong , Kamp Martin , Schneider Christian , Höfling Sven , Deng Hui
Published: February 2015

We report the construction of decoupled, coupled, and quasi-one dimensional polariton systems from zero dimensional polariton quantum boxes using microcavities with sub-wavelength gratings as the top mirror. By designing the tethering patterns around the suspended sub-wavelength gratings, we control the coupling between individual quantum boxes through different optical potentials. Energy levels and real-space or momentum space distributions of the confined modes were measured, which agreed well with simulations.
Comparison of calculated and measured refractive index profiles of continuous wave ultravoilet written waveguides in LiNbO3 and its analysis by effective index based matrix method
Authors: Ghosh Tapas , Samanta Bidyut , Jana Paresh Chandra , Ganguly Pranabendu
Published: February 2015

The refractive index profiles of the continuous wave (CW) UV-written waveguides in congruent LiNbO3 crystal are theoretically computed and compared with the evaluated profiles from the measured mode intensity distributions. It has been observed that change in activation energy of Li-indiffusion affects the computed refractive index profiles to a large extent, and the computed and measured profiles match fairly well for 305 nm and 275 nm written waveguides with an activation energy equal to ∼1.3 eV. The calculated refractive index profiles are used in effective index based matrix method (EIMM) to compute the guided mode propagation constants of these waveguides at 632.8 nm transmitting wavelength. For both the writing wavelengths, the waveguides are single mode in nature, which tally with experimental results. The bending losses of the bent waveguides for different bending radii are also computed using a conformal mapping technique along with EIMM. Finally, the behavior of CW UV-written waveguides under an applied electric field is physically analyzed. Accumulated space charge for 305 nm written waveguides is identified for its comparatively low electro-optic coefficient than the waveguide written with 275 nm UV laser.
Effect of terrain heterogeneity on feeding site selection and livestock movement patterns
Authors: Bailey Derek W. , Stephenson Mitchell B. , Pittarello Marco
Published: February 2015

Feeding site selection is a critical part of livestock foraging that can constrain and/or increase the choices available during diet selection. When livestock choose new feeding sites, vegetation and nutrient profiles can differ from other areas, especially in heterogeneous environments with rugged terrain. Correspondingly, livestock should remain longer in feeding sites in rugged heterogeneous pastures than in homogeneous pastures where animals may alternate among feeding sites to facilitate diet mixing and to prevent satiation. The objective of this study was evaluate how terrain and corresponding heterogeneity may affect the sequence and pattern of feeding site selection of free-roaming livestock. Grazing patterns of mature cows were evaluated on six ranches located in Arizona, Montana and New Mexico. In total, 11–19 cows were tracked for 1–3-month periods at each ranch by using global positioning system (GPS) collars. Positions were recorded at 10- or 15-min intervals and used to identify where cows grazed during the early morning (0500 hours to 1000 hours). Pastures (336–9740 ha) at each ranch were divided into seven to nine sections (48–1082 ha) as an indicator of feeding sites. Classification was based on cattle density and topographical and vegetation types. Sequences of daily section selection were evaluated using transition matrixes. For all ranches, the sequence of section selection differed from what would be expected by chance, indicating that the section selected on the following day depended on the section selected on the previous day. For ranches with relatively gentle terrain, cattle selected different feeding sites ~70% of the tracking period. In contrast, cows at the ranch with the largest pasture and enclosing both mountainous and gentle terrain stayed in the same feeding site for over 10 successive days for 42% of the tracking period. Smaller pastures with only mountainous terrain were intermediate. Cows grazing gentle topography and relatively homogeneous vegetation alternated among feeding sites (sections in the present study) more frequently than cows grazing pastures with more rugged topography and more heterogeneous vegetation. This pattern could help livestock mix forages and select a more diverse diet.
Feeding behaviour in ruminants: a consequence of interactions between a reward system and the regulation of metabolic homeostasis
Authors: Ginane C. , Bonnet M. , Baumont R. , Revell D. K.
Published: February 2015

Feeding behaviour, through both diet selection and food intake, is the predominant way that an animal attempts to fulfil its metabolic requirements and achieve homeostasis. In domestic herbivores across the wide range of production practices, voluntary feed intake is arguably the most important factor in animal production, and a better understanding of systems involved in intake regulation can have important practical implications in terms of performance, health and welfare. In this review, we provide a conceptual framework that highlights the critical involvement and interconnections of two major regulatory systems of feeding behaviour: the reward and the homeostatic systems. A review of the literature on ruminants and rodents provides evidence that feeding behaviour is not only shaped by homeostatic needs but also by hedonic and motivational incentives associated with foods through experiences and expectations of rewards. The different brain structures and neuronal/hormonal pathways involved in these two regulatory systems is evidence of their different influences on feeding behaviours that help explain deviation from behaviour based solely on satisfying nutritional needs, and offers opportunities to influence feeding motivation to meet applied goals in livestock production. This review further highlights the key contribution of experience in the short (behavioural learning) and long term (metabolic learning), including the critical role of fetal environment in shaping feeding behaviour both directly by food cue–consequence pairings and indirectly via modifications of metabolic functioning, with cascading effects on energy balance and body reserves and, consequently, on feeding motivation.
Role of calcium-binding sites in calcium-dependent membrane association of annexin A4
Authors: Arii Yasuhiro , Butsusihta Kohei , Fukuoka Shin-Ichi
Published: February 2015

Annexin A4 (Anx4) is a cytosolic calcium-binding protein with four repeat domains, each containing one calcium-binding site (CBS). The protein interacts with the phospholipid membrane through the CBS-coordinated calcium ion, although the role of each CBS in the calcium-dependent association is unclear. To determine the role of each CBS, 15 CBS-abolished variants were produced in various combinations by substitution of a calcium-liganding residue on each CBS by Ala. Various mutant combinations produced different influences on calcium-dependent membrane-binding behavior and on the sodium-dependent dissociation of membrane-bound Anx4. Our data suggest the interaction of Anx4 with the lipid membrane consists of strong and weak interactions. CBSs I and IV mediate formation of strong interactions, while CBSs II and III are important for weak interactions. We also suggest Anx4 binds the lipid membrane through CBSs I and IV in the cytoplasmic fluids.
A putative porin gene of Burkholderia sp. NK8 involved in chemotaxis toward β-ketoadipate
Authors: Yamamoto-Tamura Kimiko , Kawagishi Ikuro , Ogawa Naoto , Fujii Takeshi
Published: February 2015

Burkholderia sp. NK8 can utilize 3-chlorobenzoate (3CB) as a sole source of carbon because it has a megaplasmid (pNK8) that carries the gene cluster (tfdT-CDEF) encoding chlorocatechol-degrading enzymes. The expression of tfdT-CDEF is induced by 3CB. In this study, we found that NK8 cells were attracted to 3CB and its degradation products, 3- and 4-chlorocatechol, and β-ketoadipate. Capillary assays revealed that a pNK8-eliminated strain (NK82) was defective in chemotaxis toward β-ketoadipate. The introduction of a plasmid carrying a putative outer membrane porin gene, which we name ompNK8, into strain NK82 restored chemotaxis toward β-ketoadipate. RT-PCR analyses demonstrated that the transcription of the ompNK8 gene was enhanced in the presence of 3CB.
Suppressing effect of cordycepin on the lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells
Authors: Imamura Kenta , Asai Momoko , Sugamoto Kazuhiro , Matsumoto Tomoko , Yamasaki Yumi , Kamei Ichiro , Hattori Takahiro , Kishimoto Masaoki , Niisaka Seiji , Kubo Masaomi , Nishiyama Kazuo , Yamasaki Masao
Published: February 2015

In this study, we focused on the anti-inflammatory effect of cordycepin, 3′-deoxyadenosine. Cordycepin potently suppressed nitric oxide production in lipopolysaccharide-stimulated RAW 264.7 cells in an adenosine receptor-independent manner. In addition, inhibitors for adenosine kinase and nucleoside transporter abrogated the action of cordycepin. Thus, we considered that intracellular metabolism cordycepin is important for the anti-inflammatory effect of cordycepin.