bluuebunny/crossref_metadata_2025 huggingface dataset:
Fringe Benefits Among US Orthopedic Residency Programs Vary Considerably: A National Survey
Authors: Clement R. Carter , Olsson Erik , Katti Prateek , Esther Robert J.
Published: March 2016

Background

Residency programs compete to attract applicants based on numerous factors. Previous research has suggested that medical students consider quality of life among the most important factors in selecting a program. One aspect of workplace quality of life is the cadre of non-monetary benefits offered to employees. However, with federal funding for graduate medical education (GME) under consideration for spending cuts, the source and continuation of such benefits may be in question.

Questions/Purposes

This study aimed to determine the level and variability of benefits beyond standard salary and insurance options available to trainees at US orthopedic residency programs and to assess the source of funding for those benefits.

Methods

A 26-question survey investigating various benefits and funding sources was circulated by email to all ACGME-accredited orthopedic residency programs.

Results

The survey was sent to 153 programs and 69 responded (45%). The majority offers their residents discretionary funds (77%) and conference funding (96%), most of which comes from the department, followed by the hospital or GME funding. Forty-one percent of respondents permit their residents to moonlight. The majority of respondents provide meal stipends (93%), free parking (71%), gym benefits (63%), surgical loupes (53%), and maternity/paternity leave beyond vacation time (55%). No statistically significant differences were found among top ranked residencies, top ranked orthopedic hospitals, or academic centers compared to their counterparts.

Conclusion

While some benefits are commonly offered, there is great variation in the availability and level of others. However, these differences were independent of program and hospital reputation as well as academic center status. Departments currently bear a substantial amount of the cost of these benefits internally.
Enhanced flagellar swimming through a compliant viscoelastic network in Stokes flow
Authors: Wróbel Jacek K. , Lynch Sabrina , Barrett Aaron , Fauci Lisa , Cortez Ricardo
Published: March 2016

In many physiological settings, microorganisms must swim through viscous fluids with suspended polymeric networks whose length scales are comparable to that of the organism. Here we present a model of a flagellar swimmer moving through a compliant viscoelastic network immersed in a three-dimensional viscous fluid. The swimmer moves with a prescribed gait, exerting forces on the fluid and the heterogeneous network. The viscoelastic structural links of this network are stretched or compressed in response to the fluid flow caused by these forces, and these elastic deformations also generate forces on the viscous fluid. Here we track the swimmer as it leaves a region of Newtonian fluid, enters and moves through a heterogeneous network and finally enters a Newtonian region again. We find that stiffer networks give a boost to the velocity of the swimmer. In addition, we find that the efficiency of swimming is dependent upon the evolution of the compliant network as the swimmer progresses through it.
Influence of tillage systems and nitrogen management on grain yield, grain protein and nitrogen-use efficiency in UK spring wheat
Authors: RIAL-LOVERA K. , DAVIES W. P. , CANNON N. D. , CONWAY J. S.
Published: March 2016

Effects of soil tillage systems and nitrogen (N) fertilizer management on spring wheat yield components, grain yield and N-use efficiency (NUE) were evaluated in contrasting weather of 2013 and 2014 on a clay soil at the Royal Agricultural University's Harnhill Manor Farm, Cirencester, UK. Three tillage systems – conventional plough tillage (CT), high intensity non-inversion tillage (HINiT) and low intensity non-inversion tillage (LINiT) for seedbed preparation – were compared at four rates of N fertilizer (0, 70, 140 and 210 kg N/ha). Responses to the effects of the management practices were strongly influenced by weather conditions and varied across seasons. Grain yields were similar between LINiT and CT in 2013, while CT produced higher yields in 2014. Nitrogen fertilization effects also varied across the years with no significant effects observed on grain yield in 2013, while in 2014 applications up to 140 kg N/ha increased yield. Grain protein ranged from 10·1 to 14·5% and increased with N rate in both years. Nitrogen-use efficiency ranged from 12·6 to 49·1 kg grain per kg N fertilizer and decreased as N fertilization rate increased in both years. There was no tillage effect on NUE in 2013, while in 2014 NUE under CT was similar to LINiT and higher than HINiT. The effect of tillage and N fertilization on soil moisture and soil mineral N (SMN) fluctuated across years. In 2013, LINiT showed significantly higher soil moisture than CT, while soil moisture did not differ between tillage systems in 2014. Conventional tillage had significantly higher SMN at harvest time in 2014, while no significant differences on SMN were observed between tillage systems in 2013. These results indicate that LINiT can be used to produce similar spring wheat yield to CT on this particular soil type, if a dry cropping season is expected. Crop response to N fertilization is limited when soil residual N is higher, while in conditions of lower residual SMN, a higher N supply is needed to increase yield and improve grain protein content.
The sound of one hand clapping: Overdetermination and the pansensory nature of communication
Authors: Aitken Kenneth John
Published: March 2016

Two substantive issues are relevant to discussions of the evolution of acoustic communication and merit further consideration here. The first is the importance of communicative ontogeny and the impact of the proximal social environment on the early development of communication and language. The second is the emerging evidence for a number of non-linguistic roles of FOXP2 and its orthologs.
Functions of the cortico-basal ganglia circuits for spoken language may extend beyond emotional-affective modulation in adults
Authors: Hanakawa Takashi , Hosoda Chihiro
Published: March 2016

We support Ackermann et al.'s proposal that the cortico-basal ganglia circuits may play essential roles in the evolution of spoken language. Here we discuss further evidence indicating that the cortico-basal ganglia circuits may contribute to various aspects of spoken language including planning, learning, and controlling of speech in adulthood.
La Documentation de l’Afrique portugaise
Authors: Chilcote Ronald H. , Duignan Peter , Presseisen E. L.
Published: March 2016

Parce que l’Angola et le Portugal se trouvent constamment dans la presse ces jours-ci, nous avons pensé qu’une étude de sources, archives, et mouvements sur les Portugais en Afrique serait précieuse pour les lecteurs. Des documents pour l’étude de l’Afrique portugaise sont éparpillés un peu partout (et ils ne constituent qu’une source fragmentaire); les endroits où cette documentation existe ne sont généralement pas connus. Nous avons done essayé de constituer une liste partielle d’instituts, bibliothèques, et des sources sous forme de périodiques ou de livres ayant trait à ce sujet. Nous voulohs aussi fournir un guide des groupes politiques luttant pour la domination de 1’empire portugais en Afrique.
Helicobacter pyloriouter membrane protein and virulence marker differences in expatriate patients
Authors: YAKOOB J. , ABBAS Z. , JAFRI W. , KHAN R. , SALIM S A. , AWAN S. , ABID S. , HAMID S. , AHMAD Z.
Published: March 2016

We studied the prevalence ofHelicobacter pylorivirulence markers, e.g. cytotoxin associated gene (cagA),cagA promoter, vacuolating associated cytotoxin A (vacA) alleles induced by contact with epithelium (iceA type), and outer membrane protein Q (hopQ) in expatriates and compared them with those in local residents. Gastric biopsies were obtained at endoscopy for culture, histology and PCR for virulence marker andhopQ. Of 309 patients, 236 (76%) were males with a mean age of 45 years. A total of 102 patients were expatriates.hopQ type 1 was present in 98 (47%) local residents compared to 88 (86%) expatriates (P< 0·001), whilehopQ type 2 was present in 176 (85%) local residents, compared to 60 (59%) expatriates (P< 0·001).H. pylorivirulence markercagA was positive in 97 (47%) local residents compared to 86 (84%) expatriates (P< 0·001) whilecagA-P was positive in 72 (35%) local residents compared to 87 (85%) expatriates (P< 0·001).iceA type 1 was positive in 157 (76%) local residents compared to 45 (44%) expatriates (P< 0·001), whileiceA type 2 was positive in 81 (39%) local residents compared to 86 (84%) expatriates (P< 0·001). Distribution ofH. pylori cagA,cagA promoter,iceA andhopQ type in local residents and expatriates was different.H. pylorivirulence markers were associated with severe pathology in expatriates.
Assessing tree germination resilience to global warming: a manipulative experiment using sugar maple (Acer saccharum)
Authors: Solarik Kevin A. , Gravel Dominique , Ameztegui Aitor , Bergeron Yves , Messier Christian
Published: March 2016

A climate warming of 2–5°C by the end of the century will impact the likelihood of seed germination of sugar maple (Acer saccharum), a dominant tree species which possesses a restricted temperature range to ensure successful reproduction. We hypothesize that seed origin affects germination due to the species' local adaptation to temperature. We tested this by experimentally investigating the effect of incubation temperature and temperature shifting on sugar maple seed germination from seven different seed sources representing the current species range. Survival analysis showed that seeds from the northern range had the highest germination percentage, while the southern range had the lowest. The mean germination percentage under constant temperatures was best when temperatures were ≤5°C, whereas germination percentages plummeted at temperatures ≥11°C (5.8%). Cool shifting increased germination by 19.1% over constant temperature treatments and by 29.3% over warm shifting treatments. Both shifting treatments caused earlier germination relative to the constant temperature treatments. A climate warming of up to +5°C is shown to severely reduce germination of seeds from the southern range. However, under a more pronounced warming of 7°C, seed germination at the northern range become more affected and now comparable to those found from the southern range. This study states that the high seed germination percentage found in sugar maple at the northern range makes it fairly resilient to the warmest projected temperature increase for the next century. These findings provide forest managers with the necessary information to make accurate projections when considering strategies for future regeneration while also considering climate warming.
BK channel inactivation gates daytime excitability in the circadian clock
Authors: Whitt Joshua P. , Montgomery Jenna R. , Meredith Andrea L.
Published: March 2016

Inactivation is an intrinsic property of several voltage-dependent ion channels, closing the conduction pathway during membrane depolarization and dynamically regulating neuronal activity. BK K+ channels undergo N-type inactivation via their β2 subunit, but the physiological significance is not clear. Here, we report that inactivating BK currents predominate during the day in the suprachiasmatic nucleus, the brain’s intrinsic clock circuit, reducing steady-state current levels. At night inactivation is diminished, resulting in larger BK currents. Loss of β2 eliminates inactivation, abolishing the diurnal variation in both BK current magnitude and SCN firing, and disrupting behavioural rhythmicity. Selective restoration of inactivation via the β2 N-terminal ‘ball-and-chain’ domain rescues BK current levels and firing rate, unexpectedly contributing to the subthreshold membrane properties that shift SCN neurons into the daytime ‘upstate’. Our study reveals the clock employs inactivation gating as a biophysical switch to set the diurnal variation in suprachiasmatic nucleus excitability that underlies circadian rhythm.
Erratum: Conformational dynamics is key to understanding loss-of-function of NQO1 cancer-associated polymorphisms and its correction by pharmacological ligands
Authors: Medina-Carmona Encarnación , Palomino-Morales Rogelio J. , Fuchs Julian E. , Padín-Gonzalez Esperanza , Mesa-Torres Noel , Salido Eduardo , Timson David J. , Pey Angel L.
Published: March 2016

Scientific Reports 6: Article number: 20331; published online: 3 February 2016; updated: 04 March 2016 The original version of this Article contained errors in the spelling of the authors Encarnación Medina-Carmona, Esperanza Padín-Gonzalez and Noel Mesa-Torres which were incorrectly given as Medina-Carmona Encarnación, Padín-Gonzalez Esperanza and Mesa-Torres Noel.
Abnormal correlation between phase transformation and cooling rate for pure metals
Authors: Han J. J. , Wang C. P. , Liu X. J. , Wang Y. , Liu Z.-K. , Zhang T.-Y. , Jiang J. Z.
Published: March 2016

This work aims to achieve deep insight into the phenomenon of phase transformation upon rapid cooling in metal systems and reveal the physical meaning of scatter in the time taken to reach crystallization. The total number of pure metals considered in this work accounts for 14. Taking pure copper as an example, the correlation between phase selection of crystal or glass and cooling rate was investigated using molecular dynamic simulations. The obtained results demonstrate that there exists a cooling rate region of 6.3 × 1011–16.6 × 1011 K/s, in which crystalline fractions largely fluctuate along with cooling rates. Glass transformation in this cooling rate region is determined by atomic structure fluctuation, which is controlled by thermodynamic factors. According to the feature of bond-orientation order at different cooling rates, we propose two mechanisms of glass formation: (i) kinetic retardation of atom rearrangement or structural relaxation at a high cooling rate; and (ii) competition of icosahedral order against crystal order near the critical cooling rate.
Probing the origin of excitonic states in monolayer WSe2
Authors: Huang Jiani , Hoang Thang B. , Mikkelsen Maiken H.
Published: March 2016

Two-dimensional transition metal dichalcogenides (TMDCs) have spurred excitement for potential applications in optoelectronic and valleytronic devices; however, the origin of the dynamics of excitons, trions and other localized states in these low dimensional materials is not well-understood. Here, we experimentally probed the dynamics of excitonic states in monolayer WSe2 by investigating the temperature and polarization dependent photoluminescence (PL) spectra. Four pronounced PL peaks were identified below a temperature of 60 K at near-resonant excitation and assigned to exciton, trion and localized states from excitation power dependence measurements. We find that the localized states vanish above 65 K, while exciton and trion emission peaks remain up to room temperature. This can be explained by a multi-level model developed for conventional semiconductors and applied to monolayer TMDCs for the first time here. From this model, we estimated a lower bound of the exciton binding energy of 198 meV for monolayer WSe2 and explained the vanishing of the localized states. Additionally, we observed a rapid decrease in the degree of circular polarization of the PL at increasing temperatures indicating a relatively strong electron-phonon coupling and impurity-related scattering. Our results reveal further insight into the excitonic states in monolayer WSe2 which is critical for future practical applications.
Enhancement of artificial magnetism via resonant bianisotropy
Authors: Markovich Dmitry , Baryshnikova Kseniia , Shalin Alexander , Samusev Anton , Krasnok Alexander , Belov Pavel , Ginzburg Pavel
Published: March 2016

All-dielectric “magnetic light” nanophotonics based on high refractive index nanoparticles allows controlling magnetic component of light at nanoscale without having high dissipative losses. The artificial magnetic optical response of such nanoparticles originates from circular displacement currents excited inside those structures and strongly depends on geometry and dispersion of optical materials. Here an approach for enhancing of magnetic response via resonant bianisotropy effect is proposed and analyzed. The key mechanism of enhancement is based on electric-magnetic interaction between two electrically and magnetically resonant nanoparticles of all-dielectric dimer. It was shown that proper geometrical arrangement of the dimer in respect to the incident illumination direction allows flexible control over all vectorial components of the magnetic moment, tailoring the latter in the dynamical range of 100% and delivering enhancement up to 36% relative to performances of standalone spherical particles. The proposed approach provides pathways for designs of all-dielectric metamaterials and metasurfaces with strong magnetic responses.
A continuous sirtuin activity assay without any coupling to enzymatic or chemical reactions
Authors: Schuster Sabine , Roessler Claudia , Meleshin Marat , Zimmermann Philipp , Simic Zeljko , Kambach Christian , Schiene-Fischer Cordelia , Steegborn Clemens , Hottiger Michael O. , Schutkowski Mike
Published: March 2016

Sirtuins are NAD+ dependent lysine deacylases involved in many regulatory processes such as control of metabolic pathways, DNA repair and stress response. Modulators of sirtuin activity are required as tools for uncovering the biological function of these enzymes and as potential therapeutic agents. Systematic discovery of such modulators is hampered by the lack of direct and continuous activity assays. The present study describes a novel continuous assay based on the increase of a fluorescence signal subsequent to sirtuin mediated removal of a fluorescent acyl chain from a modified TNFα-derived peptide. This substrate is well recognized by human sirtuins 1–6 and represents the best sirtuin 2 substrate described so far with a kcat/KM-value of 176 000 M−1s−1. These extraordinary substrate properties allow the first determination of Ki-values for the specific Sirt2 inhibitory peptide S2iL5 (600 nM) and for the quasi-universal sirtuin inhibitor peptide thioxo myristoyl TNFα (80 nM).
A liquid-crystal-based DNA biosensor for pathogen detection
Authors: Khan Mashooq , Khan Abdur Rahim , Shin Jae-Ho , Park Soo-Young
Published: March 2016

A liquid-crystal (LC)-filled transmission electron microscopy (TEM) grid cell coated with the cationic surfactant dodecyltrimethylammonium bromide (DTAB), to which a single-stranded deoxyribonucleic acid probe (ssDNAprobe) was adsorbed at the LC/aqueous interface (TEMDTAB/DNA), was applied for the highly specific detection of target DNA molecules. The DTAB-coated E7 (used LC mixture) in the TEM grid (TEMDTAB) exhibited a homeotropic orientation, and changed to a planar orientation upon adsorption of the ssDNAprobe. The TEMDTAB/DNA was then exposed to complementary (target) ssDNA, which resulted in a planar-to-homeotropic configurational change of E7 that could be observed through a polarized optical microscope under crossed polarizers. The optimum adsorption density (2 μM) of ssDNAprobe enabled the detection of ≥0.05 nM complementary ssDNA. This TEMDTAB/DNA biosensor could differentiate complementary ssDNA from mismatched ssDNA as well as double-stranded DNA. It also successfully detected the genomic DNAs of the bacterium Erwinia carotovora and the fungi Rhazictonia solani. Owe to the high specificity, sensitivity, and label-free detection, this biosensor may broaden the applications of LC-based biosensors to pathogen detection.
Reversible control of current across lipid membranes by local heating
Authors: Urban Patrick , Kirchner Silke R. , Mühlbauer Christian , Lohmüller Theobald , Feldmann Jochen
Published: March 2016

Lipid membranes are almost impermeable for charged molecules and ions that can pass the membrane barrier only with the help of specialized transport proteins. Here, we report how temperature manipulation at the nanoscale can be employed to reversibly control the electrical resistance and the amount of current that flows through a bilayer membrane with pA resolution. For this experiment, heating is achieved by irradiating gold nanoparticles that are attached to the bilayer membrane with laser light at their plasmon resonance frequency. We found that controlling the temperature on the nanoscale renders it possible to reproducibly regulate the current across a phospholipid membrane and the membrane of living cells in absence of any ion channels.
Molecular switching involving metastable states: molecular thermal hysteresis and sensing of environmental changes by chiral helicene oligomeric foldamers
Authors: Shigeno Masanori , Kushida Yo , Yamaguchi Masahiko
Published: March 2016

Molecular switching involving metastable states by chiral helicene oligomeric foldamers exhibits notable non-equilibrium thermodynamic properties, which can be used for sensing environmental changes.
Werner clathrate formation with polyaromatic hydrocarbons: comparison of different crystallisation methods
Authors: Wicht Merrill M. , Su Hong , Báthori Nikoletta B. , Nassimbeni Luigi R.
Published: March 2016

Werner clathrates of bis-isothiocyanato tetrakis-vinylpyridine nickel(ii), with polyaromatic hydrocarbons were formed by a variety of methods such as solution crystallization, grinding, slurrying and co-melting; single crystal structures and kinetic properties are discussed.
Is the boundary layer of an ionic liquid equally lubricating at higher temperature?
Authors: Hjalmarsson Nicklas , Atkin Rob , Rutland Mark W.
Published: March 2016

Atomic force microscopy has been used to study the effect of temperature on normal forces and friction for the room temperature ionic liquid (IL) ethylammonium nitrate (EAN), confined between mica and a silica colloid probe at 25 °C, 50 °C, and 80 °C.
High resolution scanning near field mapping of enhancement on SERS substrates: comparison with photoemission electron microscopy
Authors: Awada C. , Plathier J. , Dab C. , Charra F. , Douillard L. , Ruediger A.
Published: March 2016

The need for a dedicated spectroscopic technique with nanoscale resolution to characterize SERS substrates pushed us to develop a proof of concept of a functionalized tip–surface enhanced Raman scattering (FTERS) technique.
Shape dependence of the electrochemical properties of α-Fe2O3particles as anode materials for lithium ion batteries
Authors: Lu J. F. , Tsai Y. Y. , Tsai C. J.
Published: March 2016

Cyclic performance and coulombic efficiency at 0.1C for electrodes fabricated using different shapes of α-Fe2O3nanoparticles.
Triangular lattice exciton model
Authors: Gunlycke Daniel , Tseng Frank
Published: March 2016

Exciton states in monolayer WS2 on the lattice scale being neither Frenkel nor Wannier excitons.
Free energy contributions and structural characterization of stacking disordered ices
Authors: Hudait Arpa , Qiu Siwei , Lupi Laura , Molinero Valeria
Published: March 2016

Dispersion in cubicity is not sufficient to account for the broad range of stabilities of stacking disordered ices.
Correction: The thermodynamics of endosomal escape and DNA release from lipoplexes
Authors: Avital Yotam Y. , Grønbech-Jensen Niels , Farago Oded
Published: March 2016

Correction for ‘The thermodynamics of endosomal escape and DNA release from lipoplexes’ by Yotam Y. Avital et al., Phys. Chem. Chem. Phys., 2016, 18, 2591–2596.
Carbon coated porous nickel phosphides nanoplates for highly efficient oxygen evolution reaction
Authors: Yu Xin-Yao , Feng Yi , Guan Buyuan , (David) Lou Xiong Wen , Paik Ungyu
Published: March 2016

Prussian blue analogue (PBA)-derived carbon coated porous nickel phosphides nanoplates exhibit enhanced electrocatalytic activity for oxygen evolution reaction.
Microwave-assisted direct oxidative synthesis of α-ketoamides from aryl methyl ketones and amines by a water soluble Cu(i)-complex
Authors: Nekkanti Shalini , Veeramani Karuna , Praveen Kumar Niggula , Shankaraiah Nagula
Published: March 2016

A stable and isolable Cu(i) complex has been identified for the direct oxidative synthesis of α-ketoamides in water.
Construction method of BBC and its implementation
Authors: Hong Lv , Wanli Chen , Peng Qi , Quanling Sun , Zhixiang Hua
Published: March 2016

A method of constructing codes with a low jump rate, called bit‐block‐code (BBC), is presented. The BBC has the structure of BBC, in which bits constitute a block and blocks form codes. Each bit of a block has no weight and each block has weight determined completely by its position in the circuit. The modular design for the BBC generator is also proposed where blocks are basic units of the BBC generator. The generation circuit has the characteristics of being simple, modular, and extensible. The BBC can be used as test vectors to reduce the power consumption of the circuit under test, and it can also be exploited as a code for general purposes.
Photonic versatile waveform generation based on phase modulation in Sagnac loop
Authors: Gao Yongsheng , Jiang Wei , Wen Aijun , Liang Dong , Tan Qinggui
Published: March 2016

A photonic versatile waveform generator based on phase modulation in a Sagnac loop is proposed and experimentally verified. A continuous‐wave light is modulated by a sinusoidal signal in a phase modulator to generate optical sidebands. Combined with a polariser, the Sagnac loop is used to manipulate the carrier of the modulated signal. Then, a fibre Bragg grating is applied to attenuate one of the first‐order sidebands. By properly choosing the modulation index and the polarisation state of the light wave output from the Sagnac loop, versatile waveform sequences can be generated. In the demonstrating experiment, full‐duty‐cycle sawtooth, triangular and square waveform sequences are successfully generated. The proposed photonic microwave waveform generator features the advantages of a simple structure, low cost, being free from bias drift and tunability in repetition rate.
Sign algorithm for blind channel equalisation
Authors: Abrar S.
Published: March 2016

A new admissible hardware‐efficient adaptive blind sign equalisation algorithm for quadrature amplitude modulation systems is presented. The main idea is to amplify the equalised sequence while constraining it to not to exceed the largest signal amplitude. Simulation results demonstrate improved performance in terms of mean squared error and inter‐symbol interference measures.
Foetal ECG extraction by support vector regression
Authors: Wei Zheng , Xiaolong Li , Xueyun Wei , Hongxing Liu
Published: March 2016

A new method to extract the foetal electrocardiogram (ECG) using an abdominal ECG signal and a thoracic ECG signal of the mother is presented. The nonlinear mapping of the maternal ECG component from thoracic signal to an abdominal signal is approximated by the support vector regression (SVR) method. The foetal ECG signal is then extracted by subtracting the mapped thoracic signal from an abdominal signal. In an SVR algorithm, the nonlinear regression problem in an original signal space is transformed into a linear regression problem in high‐dimensional Hilbert space by kernel technology. It avoids the ‘overfitting’ problem and could obtain good results for the small sample training set. The validity of the proposed method is validated by the real ECG signals, and compared with the existing method.
Progressive algebraic Chase decoding algorithms for Reed–Solomon codes
Authors: Zhao Jiancheng , Chen Li , Ma Xiao , Johnston Martin
Published: March 2016

This study proposes a progressive algebraic Chase decoding (PACD) algorithm for Reed–Solomon (RS) codes. On the basis of the received information, 2η (η > 0) interpolation test‐vectors are constructed for the interpolation‐based algebraic Chase decoding. A test‐vector reliability function is defined to assess their potential for yielding the intended message. The algebraic Chase decoding will then be performed progressively granting priority to decode the test‐vectors that are more likely to yield the message, and is then terminated once it is found. Consequently, the decoding complexity can be adapted to the quality of the received information. An enhanced‐PACD (E‐PACD) algorithm is further proposed by coupling the PACD algorithm with the adaptive belief propagation (ABP) decoding. The ABP decoding generates new test‐vectors for the PACD algorithm by enhancing the received information. It improves the Chase decoding performance without increasing the decoding complexity exponentially. It is shown that the E‐PACD algorithm's complexity can be significantly reduced by utilising the existing interpolation information of the previous Chase decodings’. Our performance evaluations show that the two proposed decoders outperform a number of existing algebraic decoding approaches. Complexity and memory analyses of the PACD algorithm are also presented, demonstrating that this is an efficient RS decoding strategy.
Online adaptive decision fusion based torque ripple reduction in permanent magnet synchronous motor
Authors: Erken Faruk , Öksüztepe Eyyüp , Kürüm Hasan
Published: March 2016

In this paper, new methods for reducing the torque ripple in permanent magnet synchronous motor are proposed. The methods are based on injection of appropriate current harmonics to motor by using adaptive decision fusion algorithms. Three different methods are used in determining injection of current harmonics based on q‐axis current, q‐axis voltage and reference value of the q‐axis current. In these methods, the decision values are linearly combined with weights, which are updated online according to an active fusion method, based on performing orthogonal projections onto convex sets describing these values. The validity of the proposed methods is tested with experimental studies under different operating conditions.
Implementation of sensorless DC‐link capacitorless inverter‐based interior permanent magnet synchronous motor drive via measuring switching‐state current ripples
Authors: Chen Yi , Liu Tian‐Hua , Cuong Nguyen Manh
Published: March 2016

This study proposes a sensorless speed‐control system for a DC‐link capacitorless inverter‐based interior permanent magnet synchronous motor (IPMSM) drive system via measuring switching‐state current‐ripples. By measuring the current‐ripple of each pulse‐width modulation switching‐state, the rotor position of the IPMSM can be estimated. As a result, the hardware of a high‐frequency sinusoidal voltage or current source is not required. In addition, by suitably selecting the different levels of the fictitious DC‐link voltage and compensating the duty cycle of the switching interval, the estimated rotor position error can be effectively reduced to nearly 50%. A 32‐bit digital signal processor, TMS‐320LF‐2407A, is used to execute the rotor position estimation algorithm and the speed‐controller. Experimental results validate the theoretical analysis. The proposed sensorless IPMSM drive can be operated from 3 to 2000 r/min. This study proposes a method to implement a DC‐link capacitorless inverter IPMSM drive system and improve its performance without injecting any high‐frequency voltage or current.
Voltage droop control at point of common coupling with arm current and capacitor voltage analysis for distribution static synchronous compensator based on modular multilevel converter
Authors: Xu Chen , Dai Ke , Chen Xinwen , Kang Yong
Published: March 2016

This study presents a kind of three‐phase three‐wire double‐star‐type transformer‐less modular multilevel converters (MMCs) in medium‐voltage distribution static synchronous compensators (DSTATCOMs) application based on pulse‐width‐modulated cascaded half‐bridge modules. An advanced steady‐state analysis for arm current and capacitor voltage is presented to give the explicit converter performance evaluation in project installation. Two key equations based on first and second component equivalent circuits are formulated to obtain the undetermined circulating second harmonic current and actual modulation index. Based on the proposed analysis, the internal active and reactive power control and the external droop control for the voltage at the point of common coupling (PCC) are introduced for MMC‐DSTATCOM, respectively. The droop control enlarges the operation area of the converter and the PCC voltage is allowed to vary in a larger acceptable range. Experiment tests acquired from a 60 V/2 kVA prototype in a simplified downscaled power distribution system verify the accuracy of the analysis and the feasibility of the PCC voltage droop control simultaneously.
Electrolysis-induced bubbling in soft solids for elastic-wave generation
Authors: Montalescot S. , Roger B. , Zorgani A. , Souchon R. , Grasland-Mongrain P. , Ben Haj Slama R. , Bera J.-C. , Catheline S.
Published: March 2016

Water electrolysis was discovered in 1800, with the famous experiment investigated here within soft tissue from an elastic-wave point of view. Indeed, we report that the rapid formation of hydrogen bubbles after transient (10 ms) electrolysis in water-based gels produces elastic waves. These bubbles are observed using an ultrafast optical camera. As the bubbles are trapped between the rigid electrode and the soft matter, they act as a source of elastic waves that are measured in the bulk using an ultrafast ultrasound scanner. The elastic-wave amplitude is shown to be in good agreement with a simple bubble model.
Flexo-chemo effect in nanoferroics as a source of critical size disappearance at size-induced phase transitions
Authors: Morozovska Anna N. , Glinchuk Maya D.
Published: March 2016

Based on Landau-Ginzburg-Devonshire approach, we explore the critical size disappearance at size induced phase transitions and reentrant phase occurrence in nanoferroics. Our calculations have shown that the physical mechanism of the exciting phenomenon can be the flexo-chemo effect, being the synergy of the spontaneous flexoelectric stresses and the chemical pressure induced by ion vacancies via Vegard effect. The flexo-chemo effect can lead to the remarkable changes of the nanoferroics phase diagrams, such as non-monotonic increase of the transition temperature and long-range order enhancement appearing under the size decrease and fulfilment of definite conditions. Since the flexo-chemo effect should exist in any nanostructured ferroics, obtained analytical results can be predictive for many of them. As a concrete example of the primary ferroics, we consider ferroelectric nanoparticles and have shown that a commonly expected transition from the ferroelectric to paraelectric phase at some small critical size is absent, so that the critical size loses its sense. Contrarily, the stabilization of the ferroelectric phase manifests itself by the enhancement of the transition temperature and polarization with the particle size decrease (ferroelectric phase reentrance), which was observed earlier in the tetragonal BaTiO3 nanospheres of radii 5–50 nm and stayed unexplained up to now.
A potentiostat featuring an integrator transimpedance amplifier for the measurement of very low currents—Proof-of-principle application in microfluidic separations and voltammetry
Authors: Koutilellis G. D. , Economou A. , Efstathiou C. E.
Published: March 2016

This work reports the design and construction of a novel potentiostat which features an integrator transimpedance amplifier as a current-monitoring unit. The integration approach addresses the limitations of the feedback resistor approach used for current monitoring in conventional potentiostat designs. In the present design, measurement of the current is performed by a precision switched integrator transimpedance amplifier operated in the dual sampling mode which enables sub-pA resolution. The potentiostat is suitable for measuring very low currents (typical dynamic range: 5 pA–4.7 μA) with a 16 bit resolution, and it can support 2-, 3- and 4-electrode cell configurations. Its operation was assessed by using it as a detection module in a home-made capillary electrophoresis system for the separation and amperometric detection of paracetamol and p-aminophenol at a 3-electrode microfluidic chip. The potential and limitations of the proposed potentiostat to implement fast potential-scan voltammetric techniques were demonstrated for the case of cyclic voltammetry.
Deuterium z-pinch as a powerful source of multi-MeV ions and neutrons for advanced applications
Authors: Klir D. , Shishlov A. V. , Kokshenev V. A. , Kubes P. , Labetsky A. Yu. , Rezac K. , Cherdizov R. K. , Cikhardt J. , Cikhardtova B. , Dudkin G. N. , Fursov F. I. , Garapatsky A. A. , Kovalchuk B. M. , Krasa J. , Kravarik J. , Kurmaev N. E. , Orcikova H. , Padalko V. N. , Ratakhin N. A. , Sila O. , Turek K. , Varlachev V. A. , Velyhan A. , Wagner R.
Published: March 2016

A novel configuration of a deuterium z-pinch has been used to generate a nanosecond pulse of fast ions and neutrons. At a 3 MA current, the peak neutron yield of (3.6 ± 0.5) × 1012 was emitted within 20 ns implying the production rate of 1020 neutrons/s. High neutron yields resulted from the magnetization of MeV deuterons inside plasmas. Whereas deuterons were trapped in the radial direction, a lot of fast ions escaped the z-pinch along the z-axis. A large number of >25 MeV ions were emitted into a 250 mrad cone. The cut-off energy of broad energy spectra of hydrogen ions approached 40 MeV. The total number of >1 MeV and >25 MeV deuterons were 1016 and 1013, respectively. Utilizing these ions offers a real possibility of various applications, including the increase of neutron yields or the production of short-lived isotopes in samples placed in ion paths. On the basis of our experiments with various samples, we concluded that a single shot would have been sufficient to obtain GBq positron activity of 13N isotopes via the 12C(d,n)13N reaction. Furthermore, the first z-pinch generated neutron radiograph produced by ≈20 ns pulses is presented in this paper.
Deep levels in as-grown and electron-irradiated n-type GaN studied by deep level transient spectroscopy and minority carrier transient spectroscopy
Authors: Duc Tran Thien , Pozina Galia , Son Nguyen Tien , Kordina Olof , Janzén Erik , Ohshima Takeshi , Hemmingsson Carl
Published: March 2016

Development of high performance GaN-based devices is strongly dependent on the possibility to control and understand defects in material. Important information about deep level defects is obtained by deep level transient spectroscopy and minority carrier transient spectroscopy on as-grown and electron irradiated n-type bulk GaN with low threading dislocation density produced by halide vapor phase epitaxy. One hole trap labelled H1 (EV + 0.34 eV) has been detected on as-grown GaN sample. After 2 MeV electron irradiation, the concentration of H1 increases and at fluences higher than 5 × 1014 cm−2, a second hole trap labelled H2 is observed. Simultaneously, the concentration of two electron traps, labelled T1 (EC – 0.12 eV) and T2 (EC – 0.23 eV), increases. By studying the increase of the defect concentration versus electron irradiation fluence, the introduction rate of T1 and T2 using 2 MeV- electrons was determined to be 7 × 10−3 cm−1 and 0.9 cm−1, respectively. Due to the low introduction rate of T1, it is suggested that the defect is associated with a complex. The high introduction rate of trap H1 and T2 suggests that the defects are associated with primary intrinsic defects or complexes. Some deep levels previously observed in irradiated GaN layers with higher threading dislocation densities are not detected in present investigation. It is therefore suggested that the absent traps may be related to primary defects segregated around dislocations.
Charge carrier localization effects on the quantum efficiency and operating temperature range of InAsxP1−x/InP quantum well detectors
Authors: Vashisht Geetanjali , Dixit V. K. , Porwal S. , Kumar R. , Sharma T. K. , Oak S. M.
Published: March 2016

The effect of charge carrier localization resulting in “S-shaped” temperature dependence of the photoluminescence peak energy of InAsxP1−x/InP quantum wells (QWs) is distinctly revealed by the temperature dependent surface photo voltage (SPV) and photoconductivity (PC) processes. It is observed that the escape efficiency of carriers from QWs depends on the localization energy, where the carriers are unable to contribute in SPV/PC signal below a critical temperature. Below the critical temperature, carriers are strongly trapped in the localized states and are therefore unable to escape from the QW. Further, the critical temperature increases with the magnitude of localization energy of carriers. Carrier localization thus plays a pivotal role in defining the operating temperature range of InAsxP1−x/InP QW detectors.
Ultrahigh fluid diffusivity in graphene-lined nanochannels
Authors: Kumar Shishir , Pratap Rudra , Raghavan Srinivasan
Published: March 2016

Control and understanding of the flow of fluids at nanoscales is of great significance to biology, separation science, energy technology, and medical diagnostics. Nanocarbons have emerged as one of the most promising materials for this quest, both as nanochannels and nanoporous membranes. However, the fluid flow in these graphitic nanostructures is not well understood, and there is a lack of straightforward route for process integration of the nanochannels. The graphene-lined nanochannels (GNCs), reported here, are aimed at solving these problems, while displaying a useful anomaly for fluidic flow. Specifically, GNCs show a large increase in the rate of removal of sacrificial materials enclosed in them. The increase is caused by 100–1000 times enhancement in the diffusivity of etchant media in the GNCs as compared to channels without graphene lining. The enhancement increases monotonically with a decrease in the height of the GNCs, which is not seen for the non-lined channels. These properties, coupled with easy and scalable fabrication, make GNCs highly suited for innovative and efficient nanofluidic devices and also for experimental investigations. We also provide a phenomenological model which assumes enhanced diffusivity of medium only near graphene surface to explain the observed dependence of diffusivity on the dimensions of the nanochannels. This rationalization of the phenomenon using only the surface effects is a significant step towards understanding anomalous fluidics of nanocarbons.
Impact of interstitial oxygen trapped in silicon during plasma growth of silicon oxy-nitride films for silicon solar cell passivation
Authors: Saseendran Sandeep S. , Saravanan S. , Raval Mehul C. , Kottantharayil Anil
Published: March 2016

Low temperature oxidation of silicon in plasma ambient is a potential candidate for replacing thermally grown SiO2 films for surface passivation of crystalline silicon solar cells. In this work, we report the growth of silicon oxy-nitride (SiOxNy) film in N2O plasma ambient at 380 °C. However, this process results in trapping of interstitial oxygen within silicon. The impact of this trapped interstitial oxygen on the surface passivation quality is investigated. The interstitial oxygen trapped in silicon was seen to decrease for larger SiOxNy film thickness. Effective minority carrier lifetime (τeff) measurements on n-type float zone silicon wafers passivated by SiOxNy/silicon nitride (SiNv:H) stack showed a decrease in τeff from 347 μs to 68 μs, for larger SiOxNy film thickness due to degradation in interface properties. From high frequency capacitance-voltage measurements, it was concluded that the surface passivation quality was governed by the interface parameters (fixed charge density and interface state density). High temperature firing of the SiOxNy/SiNv:H stack resulted in a severe degradation in τeff due to migration of oxygen across the interface into silicon. However, on using the SiOxNy/SiNv:H stack for emitter surface passivation in screen printed p-type Si solar cells, an improvement in short wavelength response was observed in comparison to the passivation by SiNv:H alone, indicating an improvement in emitter surface passivation quality.
Efficient polymer light-emitting diode with air-stable aluminum cathode
Authors: Abbaszadeh D. , Wetzelaer G. A. H. , Doumon N. Y. , Blom P. W. M.
Published: March 2016

The fast degradation of polymer light-emitting diodes (PLEDs) in ambient conditions is primarily due to the oxidation of highly reactive metals, such as barium or calcium, which are used as cathode materials. Here, we report the fabrication of PLEDs using an air-stable partially oxidized aluminum (AlOx) cathode. Usually, the high work function of aluminum (4.2 eV) imposes a high barrier for injecting electrons into the lowest unoccupied molecular orbital (LUMO) of the emissive polymer (2.9 eV below the vacuum level). By partially oxidizing aluminum, its work function is decreased, but not sufficiently low for efficient electron injection. Efficient injection is obtained by inserting an electron transport layer of poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl)] (F8BT), which has its LUMO at 3.3 eV below vacuum, between the AlOx cathode and the emissive polymer. The intermediate F8BT layer not only serves as a hole-blocking layer but also provides an energetic staircase for electron injection from AlOx into the emissive layer. PLEDs with an AlOx cathode and F8BT interlayer exhibit a doubling of the efficiency as compared to conventional Ba/Al PLEDs, and still operate even after being kept in ambient atmosphere for one month without encapsulation.
High-frequency electromagnetic properties of soft magnetic Nd2Co17 micron flakes fractured along c crystal plane with natural resonance frequency exceeding 10 GHz
Authors: Zhang Yongbo , Wang Peng , Ma Tianyong , Wang Ying , Qiao Liang , Wang Tao
Published: March 2016

Planar anisotropy Nd2Co17 flakes fractured along c crystal plane were fabricated by surfactant-assisted high-energy ball milling technique. The magnetic flakes have a diameter range of 5–20 μm and a typical thickness of approximately 120 nm. The frequency dependence of complex permeability of Nd2Co17 epoxy resin composite has been investigated in the frequency range of 0.1–18 GHz. The measurement results show that the natural resonance frequency reaches 12.5 GHz while the initial permeability survives up to 2.26. The superior high frequency properties come from the large out-of-plane anisotropy field and the flake structure fractured along the c crystal plane of Nd2Co17. The planar anisotropic Nd2Co17 flakes have significant potential applications in the high-frequency devices working in the frequency beyond 10 GHz.
Preisach-type modeling of high-temperature superconducting hysteresis
Authors: ElBidweihy Hatem
Published: March 2016

Even though Isaak Mayergoyz described it as: “much more accurate for the description of superconducting hysteresis than for the description of hysteresis of magnetic materials”, Preisach modeling of superconducting hysteresis is not a popular investigative tool. This might be due to the complexity of identifying the Preisach distribution function or due to lack of convincing physical reasoning behind pure phenomenological versions. In this paper, a two-component Preisach-type model is presented which is computationally-efficient and physically-sound. The change in the slope of the minor hysteresis loops is incorporated in the model and is attributed to reversible fluxoid motion. The model presented is clearly capable of simulating various shapes of superconducting hysteresis loops and could be easily coupled with finite element method (FEM) numerical software.