bluuebunny/crossref_metadata_2025 huggingface dataset:
Hybridization of graphene sheets with polyethylene terephthalate through the process of in situ polymerization aided by ultrasound
Authors: González Morones Pablo , Fernández Tavizón Salvador , Hernández Hernández Ernesto , Alberto Gallardo Vega Carlos , De León Santillán Arxel
Published: February 2016

A new methodology to prepare hybrid graphene–polyethylenterephthalate nanocomposites by ultrasonication is reported.
Design and development of a nanoemulsion system containing copper peptide by D-optimal mixture design and evaluation of its physicochemical properties
Authors: Samson Shazwani , Basri Mahiran , Fard Masoumi Hamid Reza , Abedi Karjiban Roghayeh , Abdul Malek Emilia
Published: February 2016

The particle size of Virgin coconut oil nanoemulsions was optimized using D-optimal mixture design and the optimum formulation was physicochemically characterized.
Influence of physical ageing on rim instability during solvent-induced dewetting of a thin polymer film
Authors: Xu Lin , Zhang Huanhuan , Ding Mingming , Lai Yuqing , Shi Tongfei
Published: February 2016

Combining experiments with molecular dynamic simulation to examine the influence of physical ageing on rim instability during solvent-induced dewetting.
Synthesis and characterization of protic ionic liquids as thermoelectrochemical materials
Authors: Siddique T. A. , Balamurugan S. , Said S. M. , Sairi N. A. , Normazlan W. M. D. W.
Published: February 2016

PILs have been designed and synthesized for energy harvesting applications. The module exhibited a maximum Se value of 420 μV K−1 which is the highest reported for PILs with the I−/I3− redox couple.
One-step preparation of graphene oxide–poly(3,4 ethylenedioxythiophene) composite films for nonvolatile rewritable memory devices
Authors: Li Yongming , Ni Xiuyuan
Published: February 2016

A nonvolatile rewritable memory composite film consisting of PEDOT and GO has been prepared by using GO-initiated photopolymerization.
A facile self-assembly strategy towards naphthalene diimide/graphene hybrids as high performance organic cathodes for lithium-ion batteries
Authors: Chen Miao , Yang Chongqing , Xu Zhixiao , Tang Yanping , Jiang Jianzhong , Liu Ping , Su Yuezeng , Wu Dongqing
Published: February 2016

A hybrid of naphthalene diimide and reduced graphene oxide (NDI–RGO) has been constructed by a facile self-assembly strategy. As the cathode material in lithium ion batteries, NDI–RGO manifests a capacity of 170 mA h g−1 at 25 mA g−1 for 260 cycles.
Entrapment and characterization of functional allosteric conformers of hemocyanin in sol–gel matrices
Authors: Minute Fabrizio , Hellmann Nadja , Spinozzi Francesco , Ortore Maria Grazia , Di Muro Paolo , Bubacco Luigi , Beltramini Mariano
Published: February 2016

Entrapment of hemocyanin in sol–gel stabilizes conformations scarcely populated in solution, allowing for their structural and functional analysis.
Atorvastatin calcium loaded PCL nanoparticles: development, optimization, in vitro and in vivo assessments
Authors: Kumar Nagendra , Chaurasia Sundeep , Patel Ravi R. , Khan Gayasuddin , Kumar Vikas , Mishra Brahmeshwar
Published: February 2016

The aim of the present study was to prepare atorvastatin calcium (ATR) loaded poly(ε-caprolactone) nanoparticles (ALPNs) to enhance the oral bioavailability, efficacy and safety profile of drugs.
Li-doped graphene for spintronic applications
Authors: Kheirabadi Narjes
Published: February 2016

For spintronic purposes, the proposed graphene based SMMs could be used as spin amplifiers, spin on/off switches and memory devices for room temperature applications.
The nature of students' chemical reasoning employed in scientific argumentation in physical chemistry
Authors: Moon A. , Stanford C. , Cole R. , Towns M.
Published: February 2016

Recent science education reform efforts have emphasized scientific practices in addition to scientific knowledge. Less work has been done at the tertiary level to consider students' engagement in scientific practices. In this work, we consider physical chemistry students' engagement in argumentation and construction of causal explanations. Students in two POGIL physical chemistry classrooms were videotaped as they engaged in discourse while solving thermodynamics problems. Videos were transcribed and transcripts were analyzed using the Toulmin Argument Pattern (TAP). Arguments were then characterized using the modes of reasoning in a learning progression on chemical thinking (CTLP) (Sevian and Talanquer, 2014). Results showed that students used primarily relational reasoning, in which no causal explanation is generated, rather a single relationship between variables was used to justify a claim. We discuss all types of reasoning present in students' arguments.
When do students recognize relationships between molecular structure and properties? A longitudinal comparison of the impact of traditional and transformed curricula
Authors: Underwood Sonia M. , Reyes-Gastelum David , Cooper Melanie M.
Published: February 2016

The ability to use a chemical structure to predict and explain phenomenon is essential to a robust understanding of chemistry; however, previous research has shown that students find it difficult to make the connection between structure and properties. In this study we examine how student recognition of the connections between structure and properties evolves during the first two years of college chemistry courses. In addition, we investigate how an alternative general chemistry curriculum (Chemistry, Life, the Universe and Everything (CLUE)) impacts students' understanding during these first two-years. Using discrete-time survival analysis to analyze student responses to the Implicit Information from Lewis Structures Instrument (IILSI), we found that it takes multiple semesters for students enrolled in a traditional curriculum to recognize that chemical structures can be used as models to predict chemical and physical properties. Students in the CLUE curriculum, however, tend to make this connection earlier than a matched cohort of students from a traditional curriculum, and this advantage is maintained throughout the two semesters of organic chemistry. In general, the control group takes an additional year of organic chemistry to reach the same level as the CLUE students after a year of general chemistry.
Polymer coordination promotes selective CO2reduction by cobalt phthalocyanine
Authors: Kramer W. W. , McCrory C. C. L.
Published: February 2016

We present a study of the mechanistic factors that transform cobalt phthalocyanine from a catalyst that shows modest performance for the electrocatalytic reduction of CO2to CO production into one of the most active and selective molecular catalyst reported in aqueous media when immobilized in a poly-4-vinylpyridine membrane
Construction of spirocarbocycles via gold-catalyzed intramolecular dearomatization of naphthols
Authors: Wu Wen-Ting , Xu Ren-Qi , Zhang Liming , You Shu-Li
Published: February 2016

A highly efficient, gold-catalyzed intramolecular dearomatization reaction of naphtholsvia5-endo-digcyclization is described. This facile and direct approach furnishes spirocarbocycles in excellent yields under mild conditions.
Evaluation of the coordination preferences and catalytic pathways of heteroaxial cobalt oximes towards hydrogen generation
Authors: Basu Debashis , Mazumder Shivnath , Niklas Jens , Baydoun Habib , Wanniarachchi Dakshika , Shi Xuetao , Staples Richard J. , Poluektov Oleg , Schlegel H. Bernhard , Verani Cláudio N.
Published: February 2016

A mechanistic investigation of the changes associated with distinct oxidation states of cobalt oximes and relevant for catalytic hydrogen generation.
Synthesis, structure, spectroscopy and reactivity of new heterotrinuclear water oxidation catalysts
Authors: Mognon Lorenzo , Mandal Sukanta , Castillo Carmen E. , Fortage Jérôme , Molton Florian , Aromí Guillem , Benet-Buchhlolz Jordi , Collomb Marie-Noëlle , Llobet Antoni
Published: February 2016

Four heterotrinuclear complexes containing the ligands 3,5-bis(2-pyridyl)pyrazolate (bpp−) and 2,2′:6′,2′′-terpyridine (trpy) of the general formula {[RuII(trpy)]2(μ-[M(X)2(bpp)2])}(PF6)2 have been prepared for the first time.
On-demand, magnetic hyperthermia-triggered drug delivery: optimisation for the GI tract
Authors: Che Rose Laili , Bear Joseph C. , Southern Paul , McNaughter Paul D. , Piggott R. Ben , Parkin Ivan P. , Qi Sheng , Hills Brian P. , Mayes Andrew G.
Published: February 2016

An orally-administered vehicle for targeted on-demand delivery to the gastrointestinal tract is presented. Hyperthermia is induced from an external AC magnetic field to melt a super paramagnetic iron oxide nanoparticle wax composite coating and hence release the capsule content.
Highly transparent quantum-dot light-emitting diodes with sputtered indium-tin-oxide electrodes
Authors: Wang Weigao , Peng Huiren , Chen Shuming
Published: February 2016

Highly transparent QD-LEDs have been demonstrated by using a ZnO buffer layer and sputtered ITO electrodes.
Comment on “Promising blood-derived biomarkers for estimation of the postmortem interval” by I. Costa, F. Carvalho, T. Magalhães, P. G. de Pinho, R. Silvestre & R. J. Dinis-Oliveira. (Toxicol. Res., 2015, 4, 1443–1452)
Authors: Meurs Joris , Szykuła Katarzyna M.
Published: February 2016

Recently, Costa et al. published an article about promising biomarkers for estimating the postmortem interval. Instead of postmortem blood, antemortem blood was putrefied in vitro by exposing the blood to a temperature gradient. However, in this way several other influencing factors were excluded, hence, the accuracy of the proposed model is doubtful. Therefore, the aim of this comment is to discuss the methodology, results and shortcomings of the study of Costa et al.
Stepwise isolation of an unprecedented silylene supported dinuclear gold(i) cation with aurophilic interaction
Authors: Khan Shabana , Pal Shiv , Kathewad Neha , Purushothaman Indu , De Susmita , Parameswaran Pattiyil
Published: February 2016

Isolation of the first Si(ii) supported dinuclear Au(i) cation with an intramolecular Au⋯Au interaction of 2.875(1) Å has been realized.
Correction: Catenane-based mechanically-linked block copolymers
Authors: Nisar Ahamed B. , Duchêne Roland , Robeyns Koen , Fustin Charles-André
Published: February 2016

Correction for ‘Catenane-based mechanically-linked block copolymers’ by B. Nisar Ahamed et al., Chem. Commun., 2016, DOI: 10.1039/c5cc09775d.
Equilibrium analysis of methylbenzene intermediates for a methanol-to-olefins process
Authors: Cai Dali , Wang Qi , Jia Zhao , Ma Yunhai , Cui Yu , Muhammad Usman , Wang Yao , Qian Weizhong , Wei Fei
Published: February 2016

An Anderson–Schulz–Flory distribution in an MTO process comes from a thermodynamic equilibrium.
Selective direct conversion of C5 and C6 sugars to high added-value chemicals by a bifunctional, single catalytic body
Authors: Barbaro Pierluigi , Liguori Francesca , Moreno-Marrodan Carmen
Published: February 2016

The selective multi-step conversion of monosaccharides to anhydro-sugar alcohols was achieved in one-pot, one-stage by a bifunctional Ru catalyst.
Signatures of protein thermal denaturation and local hydrophobicity in domain specific hydration behavior: a comparative molecular dynamics study
Authors: Chatterjee Prathit , Sengupta Neelanjana
Published: February 2016

We investigate, using atomistic molecular dynamics simulations, the association of surface hydration accompanying local unfolding in the mesophilic protein Yfh1 under a series of thermal conditions spanning its cold and heat denaturation temperatures.
Correction: Chemistry of aromatic polythioesters and polydithioesters
Authors: Abe Daisuke , Fukuda Yuichiro , Sasanuma Yuji
Published: February 2016

Correction for ‘Chemistry of aromatic polythioesters and polydithioesters’ by Daisuke Abe, et al., Polym. Chem., 2015, 6, 3131–3142.
Application of group V polyoxometalate as an efficient base catalyst: a case study of decaniobate clusters
Authors: Hayashi Shun , Yamazoe Seiji , Koyasu Kiichirou , Tsukuda Tatsuya
Published: February 2016

We demonstrated for the first time that [Nb10O28]6− exhibited base catalytic activity for aldol-type condensation reactions including Knoevenagel and Claisen–Schmidt condensation reactions.
Effect of polyethylene glycol on the antibacterial properties of polyurethane/carbon nanotube electrospun nanofibers
Authors: Shi Hengchong , Liu Haiyu , Luan Shifang , Shi Dean , Yan Shunjie , Liu Chunmei , Li Robert K. Y. , Yin Jinghua
Published: February 2016

The as-prepared nanofibers have better antibacterial properties. Incorporating PEG effectively reduced the CNT toxicity to human cells and also decreased the attachment of bacteria.
Stability of Li2CO3 in cathode of lithium ion battery and its influence on electrochemical performance
Authors: Bi Yujing , Wang Tao , Liu Meng , Du Rui , Yang Wenchao , Liu Zixuan , Peng Zhe , Liu Yang , Wang Deyu , Sun Xueliang
Published: February 2016

Lithium carbonate is an unavoidable impurity at the cathode side.
Dimerization and ligand binding in tyrosylprotein sulfotransferase-2 are influenced by molecular motions
Authors: Singh Warispreet , Karabencheva-Christova Tatyana G. , Sparagano Olivier , Black Gary W. , Petrov Petar Y. , Christov Christo Z.
Published: February 2016

Tyrosylprotein sulfotransferase-2 catalyses important, but a less explored posttranslational modification of proteins.
Correction: Study of the enhanced electronic and thermoelectric (TE) properties of ZrxHf1−x−yTayNiSn: a first principles study
Authors: Rai D. P. , Shankar A. , Sandeep Sandeep , Ghimire M. P. , Khenata R. , Thapa R. K.
Published: February 2016

Correction for ‘Study of the enhanced electronic and thermoelectric (TE) properties of ZrxHf1−x−yTayNiSn: a first principles study’ by D. P. Rai et al., RSC Adv., 2015, 5, 95353–95359.
Paper-based all-solid-state flexible micro-supercapacitors with ultra-high rate and rapid frequency response capabilities
Authors: Liu Wenwen , Lu Congxiang , Li Hongling , Tay Roland Yingjie , Sun Leimeng , Wang Xinghui , Chow Wai Leong , Wang Xingli , Tay Beng Kang , Chen Zhongwei , Yan Ji , Feng Kun , Lui Gregory , Tjandra Ricky , Rasenthiram Lathankan , Chiu Gordon , Yu Aiping
Published: February 2016

Novel micro-supercapacitors with excellent rate capability, response frequency, and cycle stability are designed.
A systematic evaluation of sorting motifs in the sodium–iodide symporter (NIS)
Authors: Darrouzet Elisabeth , Graslin Fanny , Marcellin Didier , Tcheremisinova Iulia , Marchetti Charles , Salleron Lisa , Pognonec Philippe , Pourcher Thierry
Published: February 2016

The sodium–iodide symporter (NIS) is an integral membrane protein that plays a crucial role in iodide accumulation, especially in the thyroid. As for many other membrane proteins, its intracellular sorting and distribution have a tremendous effect on its function, and constitute an important aspect of its regulation. Many short sequences have been shown to contribute to protein trafficking along the sorting or endocytic pathways. Using bioinformatics tools, we identified such potential sites on human NIS [tyrosine-based motifs, SH2-(Src homology 2), SH3- and PDZ (post-synaptic density-95/discs large tumour suppressor/zonula occludens-1)-binding motifs, and diacidic, dibasic and dileucine motifs] and analysed their roles using mutagenesis. We found that several of these sites play a role in protein stability and/or targeting to the membrane. Aside from the mutation at position 178 (SH2 plus tyrosine-based motif) that affects iodide uptake, the most drastic effect is associated with the mutation of an internal PDZ-binding motif at position 121 that completely abolishes NIS expression at the plasma membrane. Mutating the sites located on the C-terminal domain of the protein has no effect except for the creation of a diacidic motif that decreases the total NIS protein level without affecting its expression at the plasma membrane.
Power factor‐based scheduling of distributed battery energy storage units optimally allocated in bulk power systems for mitigating marginal losses
Authors: Moeini Ali , Kamwa Innocent , de Montigny Martin
Published: February 2016

This study addresses the problem of multi‐objective optimal allocation and management of multiple battery energy storage (BES) units. The multi‐objective genetic algorithm is first used to find the so‐called Pareto front while minimisation of power losses and the total installed capacity of the BES units are simultaneous objective functions. A number of solutions are chosen and developed over one year to find the best schedule for BES utilisation taking into account the power factor (PF) of the charge and discharge modes. Results of studies on the IEEE reliability test system 1996 confirm the existence of an optimal solution for loss reduction. Optimal tuning of the charge and discharge PFs has also proven effective for marginal loss reduction and saving energy every day of the year. Finally, it is shown that the power loss would decrease, even during charge hours, if PFs of BESs are optimally tuned.
Impacts of direct cyber‐power interdependencies on smart grid reliability under various penetration levels of microturbine/wind/solar distributed generations
Authors: Hashemi‐Dezaki Hamed , Askarian‐Abyaneh Hossein , Haeri‐Khiavi Homayoun
Published: February 2016

One of the major challenges in reliability evaluation of smart grid is the direct cyber‐power interdependencies (DCPIs) impacts. The less effort has been devoted in the literature to investigate the DCPIs impacts, particularly in stochastic simulating space. This study proposed a novel methodology to determine the risk assessment of smart grid due to DCPIs under various distributed generation (DG) technology scenarios. The presented method is applied to a realistic distribution grid. The several sensitivity studies are performed to investigate the pattern of DCPIs impacts as DG penetration level in various scenarios. The test results show that regardless of the DG technology scenario, the DCPIs impacts gradually increase while the DG penetration increases, and it saturates when the penetration exceeds a certain level. The numerical result implies that the scenarios having more effective performance from the reliability improvement perspective such as those consist of dispatchable DG units such as microturbine are more affected due to DCPIs.
Robust frequency‐locked loop algorithm for grid synchronisation of single‐phase applications under distorted grid conditions
Authors: Bei Tai‐Zhou , Wang Ping
Published: February 2016

The distributed power generation networks and smart grids are characterised by a high penetration of renewable energies. For purposes of improving the power quality of the distributed generation and achieving a reliable, efficient and safe operation of the grid, on the basis of the synchronisation techniques, this study proposes a robust frequency‐locked loop (FLL) algorithm for grid synchronisation of single‐phase applications under distorted grid conditions. The algorithm mainly includes a frequency‐adjustable quadrature signal generator (QSG) and a cascaded adaptive complex filter (ACF), as well as a robust frequency adaptive controller. The suggested QSG can generate two‐phase orthogonal voltages with the same attenuation ratio. In the proposed scheme, the normalised blocks and the cascaded ACF are introduced, for purposes of eliminating the influence of voltage fluctuation and the harmonics on the frequency adaptive adjustment effectively. Theoretical analysis indicates that the proposed FLL algorithm has good performance in aspects of rapidity and robustness even in the hostile envelopments caused by frequency variation, voltage fluctuation and harmonic distortion. Simulations and experimental results are provided at the end of this study to validate the good performance of the proposed algorithm.
Timed arrays of spiral antennas for circularly polarised UWB scanned patterns with low side lobes
Authors: Reyna Alberto , Panduro Marco A. , Méndez Aldo L. , Romero Gerardo
Published: February 2016

This research presents a novel design of a timed antenna array of two‐arm log spiral antennas. The design consists in optimising the non‐uniform antenna positions in order to obtain a scanned energy pattern with low side lobes in time domain. It is utilised the well‐known sequential quadratic programming for the optimisation. The non‐uniform array is compared with conventional geometries, such as square array and concentric ring array. The resulted timed antenna array is also analysed in frequency domain after the optimisation in time domain. The results revealed good performance of the non‐uniform timed antenna array for ultra wide band, circular polarisation, beam scanning and low side lobes.
Information filters with reduced data storage for out‐of‐sequence measurements update
Authors: Kim Tae Han , Song Taek Lyul , Kim Hyung June
Published: February 2016

In target tracking/fusion applications, the measurements often do not become available in the order of measurement times. Out of sequence measurements (OOSMs) are used to update state estimates for the ‘current’ time, using measurements from previous measurement times. The authors propose information filter‐based OOSM update solution(s), which forward propagate the OOSMs information filter state. This allows tradeoffs between estimation performance and storage requirements.
First‐order bistatic high‐frequency radar ocean surface cross‐section for an antenna on a floating platform
Authors: Ma Yue , Gill Eric W. , Huang Weimin
Published: February 2016

The first‐order bistatic high‐frequency radar cross‐section of ocean surface is derived for the case of a fixed receiver and a floating, but tethered, transmitter. A general expression for the bistatically received first‐order electric field is obtained from earlier work based on fixed antennas. A small displacement caused by the platform motion is added in the source term to modify the stationary antenna model. Based on the assumption that the ocean surface can be described as a Fourier series with coefficients being random variables, the first‐order bistatic radar cross‐section is derived. The effect of the platform motion is found to produce a sum of Bessel functions in the final cross‐section result, varying in order from zero to infinity. Under appropriately specified conditions, the bistatic model with antenna motion is verified to reduce to the monostatic model with antenna motion and the bistatic stationary model, respectively. Assuming a simple model in which the platform motion is caused by the dominant ocean wave, simulations are made to show the effect of platform motion on the radar cross‐section under a variety of sea states and operating frequencies.
Using an information‐theoretic measure to inform distributed radar placement for automatic target recognition
Authors: Wilcher John S. , Lanterman Aaron D. , Melvin William L.
Published: February 2016

The authors derive a measure suitable for identifying sensor placements that yield high target classification rates in a distributed radar environment. A distance measure is derived as an approximation lower bound of the Kullback–Leibler (KL) divergence between two probable target classes. A relationship between the KL divergence approximation and probability of correct classification (PCC) is demonstrated and used to identify sensor placements likely to yield higher PCC values. Two algorithms are proposed, optimal and approximate, for identifying good placements of a single transmitter and two receivers. A physics‐based scattering model is employed to generate reflectivity data suitable for multi‐sensor, multi‐static classification analysis. KL and PCC data sets are analysed to demonstrate the effectiveness of the proposed distance measure and algorithms.
Detection and parameter estimation of ground moving targets in multichannel wide‐area surveillance system based on iterative adaptive approach
Authors: Qi Lijuan , Yu Weidong , Zheng Mingjie , Hou Lili
Published: February 2016

Clutter suppression and motion parameter estimation are two of the essential issues of the signal processing in wide‐area surveillance ground moving‐target indication (WAS‐GMTI) system. In this study, the authors propose and show how the iterative adaptive approach, which is a recently proposed non‐parametric, weighted least‐squares‐based iterative adaptive processing approach, can be extended into multichannel WAS‐GMTI system, in both ground clutter suppression and target parameter estimation. Since the proposed method does not need to estimate the interference covariance matrix from the secondary data, it has a major advantage when processing the data from non‐homogeneous environments. The effectiveness of the proposed method is validated by both simulated experiments and real data processing.
How much can we trust life tables? Sensitivity of mortality measures to right-censoring treatment
Authors: Missov Trifon I , Németh László , Dańko Maciej J
Published: February 2016

International organizations, research institutions, insurance companies, pension funds and health policymakers calculate human mortality measures from life tables. Life-table data, though, are usually right-censored; that is, the last open-end age group does not contain information about the exact ages at death of individuals there, and mortality measures are sensitive to the way censoring is addressed. The standard way of “closing” the life table assumes a constant hazard of death for the last age group. This might lead to erroneous conclusions about mortality measures, especially when the open-end age interval contains a large proportion of the study population. In this article, we propose, instead, fitting a parametric model that well describes human mortality patterns, the gamma-Gompertz-Makeham, accounting for censoring, and constructing model-based equivalents of five mortality measures: life expectancy, the modal age at death, life disparity, entropy and the Gini coefficient. We show that, in comparison to conventional life-table measures, model-based measures are less sensitive to the age at censoring or, equivalently, to the proportion of censored individuals, and can be only slightly distorted even if the age at censoring is low. This study also compares life-table and model-based mortality measures for a non-human population with an underlying Gompertz mortality schedule in which a fixed proportion of the population is censored. Using model-based mortality measures is essential when studying the mortality of populations subjected to substantial censoring; for instance, many life tables for developing countries contain an open-end interval that contains more than 10% of the population. In this study, we show that life expectancy at birth for Brazilian females in 2007, calculated by standard life-table algebra, exceeds by almost 3 years the gamma-Gompertz-Makeham model-based life expectancy. This article might serve as a basis for recalculation of mortality measures for all populations subjected to substantial censoring.
GaAs/Ge crystals grown on Si substrates patterned down to the micron scale
Authors: Taboada A. G. , Meduňa M. , Salvalaglio M. , Isa F. , Kreiliger T. , Falub C. V. , Barthazy Meier E. , Müller E. , Miglio L. , Isella G. , von Känel H.
Published: February 2016

Monolithic integration of III-V compounds into high density Si integrated circuits is a key technological challenge for the next generation of optoelectronic devices. In this work, we report on the metal organic vapor phase epitaxy growth of strain-free GaAs crystals on Si substrates patterned down to the micron scale. The differences in thermal expansion coefficient and lattice parameter are adapted by a 2-μm-thick intermediate Ge layer grown by low-energy plasma enhanced chemical vapor deposition. The GaAs crystals evolve during growth towards a pyramidal shape, with lateral facets composed of {111} planes and an apex formed by {137} and (001) surfaces. The influence of the anisotropic GaAs growth kinetics on the final morphology is highlighted by means of scanning and transmission electron microscopy measurements. The effect of the Si pattern geometry, substrate orientation, and crystal aspect ratio on the GaAs structural properties was investigated by means of high resolution X-ray diffraction. The thermal strain relaxation process of GaAs crystals with different aspect ratio is discussed within the framework of linear elasticity theory by Finite Element Method simulations based on realistic geometries extracted from cross-sectional scanning electron microscopy images.
Lab-on-a-chip workshop activities for secondary school students
Authors: Esfahani Mohammad M. N. , Tarn Mark D. , Choudhury Tahmina A. , Hewitt Laura C. , Mayo Ashley J. , Rubin Theodore A. , Waller Mathew R. , Christensen Martin G. , Dawson Amy , Pamme Nicole
Published: February 2016

The ability to engage and inspire younger generations in novel areas of science is important for bringing new researchers into a burgeoning field, such as lab-on-a-chip. We recently held a lab-on-a-chip workshop for secondary school students, for which we developed a number of hands-on activities that explained various aspects of microfluidic technology, including fabrication (milling and moulding of microfluidic devices, and wax printing of microfluidic paper-based analytical devices, so-called μPADs), flow regimes (gradient formation via diffusive mixing), and applications (tissue analysis and μPADs). Questionnaires completed by the students indicated that they found the workshop both interesting and informative, with all activities proving successful, while providing feedback that could be incorporated into later iterations of the event.
Application of photon Doppler velocimetry to direct impact Hopkinson pressure bars
Authors: Lea Lewis J. , Jardine Andrew P.
Published: February 2016

Direct impact Hopkinson pressure bar systems offer many potential advantages over split Hopkinson pressure bars, including access to higher strain rates, higher strains for equivalent striker velocity and system length, lower dispersion, and faster achievement of force equilibrium. Currently, these advantages are gained at the expense of all information about the striker impacted specimen face, preventing the experimental determination of force equilibrium, and requiring approximations to be made on the sample deformation history. In this paper, we discuss an experimental method and complementary data analysis for using photon Doppler velocimetry to measure surface velocities of the striker and output bars in a direct impact bar experiment, allowing similar data to be recorded as in a split bar system. We discuss extracting velocity and force measurements, and the precision of measurements. Results obtained using the technique are compared to equivalent split bar tests, showing improved stress measurements for the lowest and highest strains in fully dense metals, and improvement for all strains in slow and non-equilibrating materials.
Angular distribution of plasma luminescence emission during filamentation in air
Authors: Li Suyu , Sui Laizhi , Chen Anmin , Jiang Yuanfei , Liu Dunli , Shi Zhe , Jin Mingxing
Published: February 2016

We experimentally measure the angular distribution of plasma luminescence emission during the filamentation of linearly polarized femtosecond laser pulses. It is found that the luminescence from N2 shares the same intensity in all directions, while that from N2+ is more intense in the direction parallel to that of the laser polarization. The isotropic emission behavior of luminescence from N2 illustrates that the formation of excited N2(C3Πu+) does not result from the dissociative recombination; on the other hand, the linear increase of the strength of 337 nm signal with pressure indicates that the collision plays a negligible role, excluding the collision assisted intersystem crossing scheme. However, the intersystem crossing does not rely on the collision, making it a possible scheme. This study will be helpful to the understanding of mechanism of plasma luminescence emission during femtosecond filamentation.
Factors affecting the f × Q product of 3C-SiC microstrings: What is the upper limit for sensitivity?
Authors: Kermany Atieh R. , Bennett James S. , Brawley George A. , Bowen Warwick P. , Iacopi Francesca
Published: February 2016

The fn × Q (Hz) is a crucial sensitivity parameter for micro-electro-mechanical sensing. We have recently shown a fn × Q product of ∼1012 Hz for microstrings made of cubic silicon carbide on silicon, establishing a new state-of-the-art and opening new frontiers for mass sensing applications. In this work, we analyse the main parameters influencing the frequency and quality factor of silicon carbide microstrings (material properties, microstring geometry, clamping condition, and environmental pressure) and investigate the potential for approaching the theoretical upper limit. We indicate that our previous result is only about a factor 2 lower than the thermoelastic dissipation limit. For fully reaching this upper limit, a substantial reduction of the defects in the silicon carbide thin film would be required, while maintaining a high residual tensile stress in the perfect-clamped strings.
In situ photoluminescence study of plasma-induced damage at the a-Si:H/c-Si interface
Authors: Lebreton F. , Abolmasov S. N. , Silva F. , Roca i Cabarrocas P.
Published: February 2016

In situ photoluminescence combined with optical emission spectroscopy, effective carrier lifetime, radio-frequency (RF) and self-bias potential measurements has been used to study plasma-induced damage at the a-Si:H/c-Si interface. Passivated crystalline silicon wafers were exposed to Ar, H2, and Ar-H2 RF plasmas using the same value of RF power and pressure in the range of 80–100 mTorr. The substrate temperature during the plasma exposure was room temperature or 200 °C. It is found that Ar-H2 plasma has the most detrimental effect on the photoluminescence intensity/effective carrier lifetime which correlates well with its UV spectrum. After plasma exposure, surface passivation can be recovered by thermal annealing—an effect similar to that observed in the case of light-induced degradation of a-Si:H.
Cubic to tetragonal phase transition of Tm3+ doped nanocrystals in oxyfluoride glass ceramics
Authors: Li Yiming , Zhao Lijuan , Fu Yuting , Shi Yahui , Zhang Xiaoyu , Yu Hua
Published: February 2016

Tm3+ ions doped β-PbF2 nanocrystals in oxyfluoride glass ceramics with different doping concentrations and thermal temperatures are prepared by a traditional melt-quenching and thermal treatment method to investigate the structure and the phase transition of Tm3+ doped nanocrystals. The structures are characterized by X-ray diffraction Rietveld analysis and confirmed with numerical simulation. The phase transitions are proved further by the emission spectra. Both of the doping concentration and thermal temperature can induce an Oh to D4h site symmetry distortion and a cubic to tetragonal phase transition. The luminescence of Tm3+ doped nanocrystals at 800 nm was modulated by the phase transition of the surrounding crystal field.
Defect reduction in overgrown semi-polar (11-22) GaN on a regularly arrayed micro-rod array template
Authors: Zhang Y. , Bai J. , Hou Y. , Smith R. M. , Yu X. , Gong Y. , Wang T.
Published: February 2016

We demonstrate a great improvement in the crystal quality of our semi-polar (11-22) GaN overgrown on regularly arrayed micro-rod templates fabricated using a combination of industry-matched photolithography and dry-etching techniques. As a result of our micro-rod configuration specially designed, an intrinsic issue on the anisotropic growth rate which is a great challenge in conventional overgrowth technique for semi-polar GaN has been resolved. Transmission electron microscopy measurements show a different mechanism of defect reduction from conventional overgrowth techniques and also demonstrate major advantages of our approach. The dislocations existing in the GaN micro-rods are effectively blocked by both a SiO2 mask on the top of each GaN micro-rod and lateral growth along the c-direction, where the growth rate along the c-direction is faster than that along any other direction. Basal stacking faults (BSFs) are also effectively impeded, leading to a distribution of BSF-free regions periodically spaced by BSF regions along the [-1-123] direction, in which high and low BSF density areas further show a periodic distribution along the [1-100] direction. Furthermore, a defect reduction model is proposed for further improvement in the crystalline quality of overgrown (11-22) GaN on sapphire.
Regional aspects of modelling burned areas in Europe
Authors: Krasovskii Andrey , Khabarov Nikolay , Migliavacca Mirco , Kraxner Florian , Obersteiner Michael
Published: February 2016

This paper presents a series of improvements to the quantitative modelling of burned areas in Europe under historical climate. The Standalone Fire Model (SFM) based on a state-of-the-art large scale mechanistic fire modelling algorithm is used to reproduce historical burned areas reported in the two publicly available datasets – European Forest Fire Information System (EFFIS) and Global Fire Emissions Database (GFED). The most recent versions of these sources allow a broader validation of SFM’s modelled burned areas at a country level. Our analysis is carried out for the years 2000–2008 for 17 European countries utilising both EFFIS and GFED datasets for model benchmarking. We suggest improving the original model by modifying the fire probability function reflecting fuel moisture. This modification allows for a dramatic improvement of accuracy in modelled burned areas for a range of European countries. We also explore in detail a pixel-level parametrisation of firefighting efficiency in SFM along with modifications of the biomass map. In comparison with the aggregated country-level approach, the advantages of the finer calibration are quite minor for the most recent version of the GFED dataset. Overall, the annual burned areas modelled by this improved SFM version are in good agreement with historical observations.
Policy impacts of ecosystem services knowledge
Authors: Posner Stephen M. , McKenzie Emily , Ricketts Taylor H.
Published: February 2016

Significance

Our study introduces a conceptual framework and empirical approach to explore how knowledge impacts decision-making. We illustrate this approach with knowledge about ecosystem services (ES), but the approach itself can be applied broadly. Our results indicate that the legitimacy of knowledge (i.e., perceived as unbiased and representative of multiple points of view) is of paramount importance for impact. More surprisingly, we found that credibility of knowledge is not a significant predictor of impact. To enhance legitimacy, ES researchers must engage meaningfully with decision-makers and stakeholders in processes of knowledge coproduction that incorporate diverse perspectives transparently. Our results indicate how research can be designed and carried out to maximize the potential impact on real-world decisions.
Regional specialization within the human striatum for diverse psychological functions
Authors: Pauli Wolfgang M. , O’Reilly Randall C. , Yarkoni Tal , Wager Tor D.
Published: February 2016

Significance

The subcortical striatum is critical for the planning and execution of motor behavior, and its dysfunction is associated with disorders such as Parkinson’s disease. More recently, the human striatum has also been reported to be involved in heterogeneous nonmotor psychological functions. However, detailed functional mappings of human psychological processes to striatal regions have been bound by theoretical and methodological limitations, including a strong focus on experimental paradigms derived from animal research, and the tendency to infer function from anatomical connectivity, rather than task-related activation. To overcome these limitations, we used a large-scale, unbiased, data-driven approach, and generated a precise, comprehensive functional map, directly associating striatal zones with the broadest range of psychological processes to date.
Brain responses in humans reveal ideal observer-like sensitivity to complex acoustic patterns
Authors: Barascud Nicolas , Pearce Marcus T. , Griffiths Timothy D. , Friston Karl J. , Chait Maria
Published: February 2016

Significance

We reveal the temporal dynamics and underlying neural sources of the process by which the brain discovers complex temporal patterns in rapidly unfolding sound sequences. We demonstrate that the auditory system, supported by a network of auditory cortical, hippocampal, and frontal sources, continually scans the environment, efficiently represents complex stimulus statistics, and rapidly (close to the bounds implied by an ideal observer model) responds to emergence of regular patterns, even when these are not behaviorally relevant. Neuronal activity correlated with the predictability of ongoing auditory input, both in terms of deterministic structure and the entropy of random sequences, providing clear neurophysiological evidence of the brain's capacity to automatically encode high-order statistics in sensory input.
Functional malignant cell heterogeneity in pancreatic neuroendocrine tumors revealed by targeting of PDGF-DD
Authors: Cortez Eliane , Gladh Hanna , Braun Sebastian , Bocci Matteo , Cordero Eugenia , Björkström Niklas K. , Miyazaki Hideki , Michael Iacovos P. , Eriksson Ulf , Folestad Erika , Pietras Kristian
Published: February 2016

Significance

Emerging evidence suggest that the cellular composition of tumors is highly heterogeneous. Subclonal species of malignant cells may account for variability in therapeutic responses and for relapse following treatments. However, little is known about the molecular drivers of specific subsets of cancer cells. Herein, we identify expression of platelet-derived growth factor receptor beta (PDGFRβ) as a previously unrecognized feature of a minor malignant cell population in pancreatic neuroendocrine tumors. By the use of mice genetically deficient for
Pdgfd
, we reveal a crucial and nonredundant function for signaling by platelet-derived growth factor (PDGF)-DD in promoting functional tumor heterogeneity by providing growth-stimulatory cues. Taken together, the use of drugs targeting PDGFRβ signaling, such as the approved targeted therapy sunitinib, may affect the functional intratumoral cross talk in pancreatic neuroendocrine tumors.
Stigmergic construction and topochemical information shape ant nest architecture
Authors: Khuong Anaïs , Gautrais Jacques , Perna Andrea , Sbaï Chaker , Combe Maud , Kuntz Pascale , Jost Christian , Theraulaz Guy
Published: February 2016

Significance

Social insects build some of the most complex nests found in the animal kingdom. Here, we use experiments and modeling to decipher the mechanisms involved in the coordination of nest building in the ant
Lasius niger
: we first characterize nest architecture and its growth with 3D imaging techniques; then, we test the building responses of individual ants to artificial stimuli. A model entirely based on experimental data confirms that the individual level interactions and building rules are sufficient to reproduce the nest growth dynamics and the spatial patterns observed for real ant nests. Our results show that a pheromone added by ants to the building material is a key factor that controls the growth and form of nest architecture.
Evolution and convergence of the patterns of international scientific collaboration
Authors: Coccia Mario , Wang Lili
Published: February 2016

Significance

The evolution of the patterns of international scientific collaboration plays an important role in the social construction of science to design efficient research policies and to support the production of knowledge. However, in studies of science, little is known about how patterns of international research collaboration for fields of science have evolved in the past four decades. This study shows, for the first time to our knowledge, starting from pioneering results described by literature in the 1970s and 1990s, that the long-run patterns of international scientific collaboration are generating a convergence between applied and basic fields. This convergence of collaboration patterns across research fields might be one of contributing factors that supports the evolution of scientific disciplines.
New approaches to quantifying aerosol influence on the cloud radiative effect
Authors: Feingold Graham , McComiskey Allison , Yamaguchi Takanobu , Johnson Jill S. , Carslaw Kenneth S. , Schmidt K. Sebastian
Published: February 2016

The topic of cloud radiative forcing associated with the atmospheric aerosol has been the focus of intense scrutiny for decades. The enormity of the problem is reflected in the need to understand aspects such as aerosol composition, optical properties, cloud condensation, and ice nucleation potential, along with the global distribution of these properties, controlled by emissions, transport, transformation, and sinks. Equally daunting is that clouds themselves are complex, turbulent, microphysical entities and, by their very nature, ephemeral and hard to predict. Atmospheric general circulation models represent aerosol−cloud interactions at ever-increasing levels of detail, but these models lack the resolution to represent clouds and aerosol−cloud interactions adequately. There is a dearth of observational constraints on aerosol−cloud interactions. We develop a conceptual approach to systematically constrain the aerosol−cloud radiative effect in shallow clouds through a combination of routine process modeling and satellite and surface-based shortwave radiation measurements. We heed the call to merge Darwinian and Newtonian strategies by balancing microphysical detail with scaling and emergent properties of the aerosol−cloud radiation system.
Ribbon curling via stress relaxation in thin polymer films
Authors: Prior Chris , Moussou Julien , Chakrabarti Buddhapriya , Jensen Oliver E. , Juel Anne
Published: February 2016

Significance

The forming of thin film structures through differential stress relaxation is an important engineering design tool to create flexible objects such as rolls, spirals, and origamis. We exploit the everyday process inspired from gift wrapping of curling an initially straight ribbon by pulling it over a blade to probe the mechanical shear response of thin polymer sheets. Experiments show that curling occurs over a limited range of loads applied to the ribbon, with the curl radius reaching a maximum at intermediate loads. A theoretical model reveals several patterns of irreversible yielding across the ribbon, and the dependence of curl radius on pulling speed shows that stress relaxes dynamically as the ribbon passes over the blade.
Charge of a quasiparticle in a superconductor
Authors: Ronen Yuval , Cohen Yonatan , Kang Jung-Hyun , Haim Arbel , Rieder Maria-Theresa , Heiblum Moty , Mahalu Diana , Shtrikman Hadas
Published: February 2016

Significance

The charge of the quasiparticles in superconductors was never, to our knowledge, directly measured. Here, we used our experience and sensitive techniques in measuring the fractional excitations in the fractional quantum Hall effect via quantum shot noise, to measure the tunneling quasiparticles in a 1D superconductor–insulator–superconductor Josephson junction, and find their charge to be significantly less than that of an electron.