bluuebunny/crossref_metadata_2025 huggingface dataset:
“Hot edges” in an inverse opal structure enable efficient CO2 electrochemical reduction and sensitive in situ Raman characterization
Authors: Yang Yang , Ohnoutek Lukas , Ajmal Saira , Zheng Xiuzhen , Feng Yiqing , Li Kejian , Wang Tao , Deng Yue , Liu Yangyang , Xu Dong , Valev Ventsislav K. , Zhang Liwu
Published: April 2019

“Hot edges” in a Cu–In monolayer inverse opal structure lead to ultrasensitive Raman signals of the intermediates and efficient electrochemical CO2 reduction performance.
In situ formation of LiF decoration on a Li-rich material for long-cycle life and superb low-temperature performance
Authors: Ding Xiang , Li Yi-Xuan , Chen Fei , He Xiao-Dong , Yasmin Aqsa , Hu Qiao , Wen Zhao-Yin , Chen Chun-Hua
Published: April 2019

The electrochemical properties of Li1.2Ni0.13Co0.13Mn0.54O2 (LLO) are improved by LiPF6 coating and subsequent heating.
High-performance blue fluorescent/electroactive polyamide bearing p-phenylenediamine and asymmetrical SBF/TPA-based units for electrochromic and electrofluorochromic multifunctional applications
Authors: Su Kaixin , Sun Ningwei , Tian Xuzhou , Guo Shuang , Yan Zhihua , Wang Daming , Zhou Hongwei , Zhao Xiaogang , Chen Chunhai
Published: April 2019

A novel EC/EFC polyamide is realized by introducing stably electroactive p-phenylenediamine and asymmetrical SBF/TPA-based unit to reduce packing.
Organic transistors on paper: a brief review
Authors: Zschieschang Ute , Klauk Hagen
Published: April 2019

Organic transistors for flexible electronics applications are usually fabricated on polymeric substrates, but considering the negative impact of plastic waste on the global environment and taking into account the desirable properties of paper, there are more and more efforts to use paper as a substrate for organic transistors.
Charge‐sharing bandpass filter with independent bandwidth and centre frequency adjustment
Authors: Ganji H. , Jannesari A. , Sohrabi Z.
Published: April 2019

A semi‐passive charge‐sharing complex bandpass filter employing positive feedback technique is proposed to control bandwidth at different centre frequencies. In contrast to the previous arts, bandwidth can be changed independent of centre frequency without any rise in the number of clock phases and switches. Also, insightful continuous‐time model and block diagram of the proposed filter have been presented. The results of simulation carried out with 0.18 µm CMOS technology at 200 MHz reference frequency for centre frequencies of 10 and 20 MHz and bandwidth of 1, 3 and 7 MHz indicate the filter's ability to control the quality factor excellently.
Roles of UV light strength and auxiliary electric field in the photocatalytic degradation effect of organic contaminant
Authors: YaoYu Lin , YanXiang Ma , XingMing Bian , PengCheng Sun
Published: April 2019

The accumulation of contaminants on the electrical devices could adversely affect the operation. The present work used photocatalytic functional material to coat on the surface of the electrical devices to prevent the influence of organic contamination. This kind of material was mainly composed of TiO2 that can remove the contamination by the effect of photooxidation. The photocatalysis was affected by the strength of UV light and electric field. In the experiment, methyl orange (MO) was used as the organic contaminant. The effect of UV light and auxiliary electric field were analysed based on the theoretical simulation. With the stronger UV light, more electron–hole pairs were generated, photocatalytic effect became more pronounced. With the auxiliary electric field, the recombination of electron and hole could be restrained that would increase the productive rate of hole; therefore, more hydroxyl radical will be produced to degrade MO.
Risk‐constrained demand response and wind energy systems integration to handle stochastic nature and wind power outage
Authors: Ghavidel Sahand , Rajabi Amin , Ghadi Mojtaba Jabbari , Azizivahed Ali , Li Li , Zhang Jiangfeng
Published: April 2019

Participation of wind generation in electricity markets is mainly restricted by the intermittent nature of wind and their possible outages. The great potential of flexible loads from demand response (DR) can be seen as a cost‐effective option to handle such issues. In this regard, this study investigates the operation of a virtual power plant (VPP) that is constructed by a DR aggregator and wind power aggregator to handle the inherent volatility of wind generators as well as the possible wind power outage. A stochastic programming formulation in three stages is offered for the VPP that participates in the balancing, intraday and day‐ahead markets. The model for DR is developed based on the elasticity concept, and the scenarios related to severe outages of the wind generators are considered. In order to manage the risk of the problem, conditional value‐at‐risk has also been employed in offering strategy. Case studies demonstrate that the VPP offering strategy can efficiently solve the balancing problem as well as outage risk of the wind generation while increasing the net profit in case of joint operation.
Enhanced radio frequency rectifier with a power splitting/combining topology for wireless energy transfer and harvesting
Authors: Abdallah Mahmoud , Costantine Joseph , Ramadan Ali H. , Tawk Youssef
Published: April 2019

Power splitting of the input radio frequency (RF) signal is used to improve the efficient power range of a RF rectifier. Direct current (dc) power at the output of every rectifying branch is then combined over a resistive load and thus resulting in a single dc output. The enhancement in efficient power range, over which the power conversion efficiency (PCE) remains ≥ 50%, is determined to be 2.8 dB. The article starts by a theoretical analysis that addresses the negative effects of the diode's breakdown voltage, formulates an equation that predicts the maximum output dc voltage at saturation, and introduces a method that can improve the PCE of a typical shunt‐type diode rectifier at low power levels. As a result, a rectifying system is designed and tested as a proof of concept. The proposed circuit, with the enhanced power range, is designed to operate within the power span from −10 dBm up until 10 dBm. Such system is suitable for operation in RF wireless energy transfer and energy harvesting applications.
Compact UWB FSS reflector for antenna gain enhancement
Authors: Yuan Yanning , Xi Xiaoli , Zhao Yuchen
Published: April 2019

In this study, two compact ultra‐wideband (UWB) frequency selective surface (FSS) reflectors, which combine the branch loading method with the design of the traditional FSS, are proposed for antenna gain enhancement application. The working mechanism of the proposed FSS reflectors is analysed by the equivalent circuit model. The first FSS reflector, which is a 10 × 10 array with 8.25 mm × 8.25 mm unit size, not only enhances the gain of the UWB antenna, but also guarantees a constant gain with only 0.5 dB variation across the whole operation band. To further reduce the reflector size, a more compact FSS reflector with 6.25 mm × 6.25 mm unit size is designed by printing similar patterns on both sides of a single‐layer dielectric slab. Compared to the first structure, the second reflector can realise a 25% size reduction and the same gain variation in the entire UWB frequency range. The only compromise is a 0.5 dB gain decrease. Finally, a good agreement between the measured and simulated results proves the feasibility of the authors’ design.
Vector control strategies to enable equal frequency operation of the modular multilevel matrix converter
Authors: Diaz Matias , Espinosa Mauricio , Rojas Felix , Wheeler Pat , Cardenas Roberto
Published: April 2019

The modular multilevel matrix converter (M3 C) is a power converter topology for ac to ac conversion that is suitable for high‐power applications. The control of this converter is complex, particularly if ac system frequencies are similar. In these cases, the floating capacitors can present large voltage oscillations. Therefore, this study presents a new vector control system to enable the operation of the M3 C when the frequencies at the input and output are virtually the same. The effectiveness of the proposed method has been validated using simulations and experimental results from a prototype M3 C power converter with 27 cells.
GaN‐based single‐phase bridgeless PFC boost rectifier
Authors: Jappe Tiago Kommers , Lohn Murilo Koerich , Mussa Samir Ahmad
Published: April 2019

A single‐phase GaN‐based bridgeless PFC Boost converter design is proposed regarding multi‐domain optimisation concepts. A design guideline describing elements losses are presented concerning the selected power converter topology. Experimental results are also depicted in 750 W power prototype digitally controlled by an FPGA device using switching frequency up to 500 kHz per active switch.
Evaluating suitable semiconducting materials for cryogenic power electronics
Authors: Bradley Luke , Donaghy‐Spargo Christopher , Atkinson Glynn , Horsfall Alton
Published: April 2019

The interest in hybrid electric aircraft has invigorated research into superconducting power networks and superconducting electrical machines. Underpinning this is the ability to control the flow of electrical current at cryogenic temperatures, using power electronic devices. The authors have, for the first time, directly compared the performance of technologically relevant semiconductor materials for the realisation of high‐performance cryogenic power devices using a bulk resistivity model. By validating the model using both computational and experimental results, the performance of technologically relevant semiconductors has been calculated down to a temperature of 20 K where the freeze out of dopants is shown to be the major limiting factor in determining the performance of power electronic devices. Both Ge and GaAs are predicted to have a superior conductivity in comparison to the industrial standards Si and 4H‐SiC due to greater carrier mobilities and lower dopant ionisation energies.
PWM‐based Flux linkage estimation for permanent magnet synchronous machines
Authors: Xiao Shuai , Griffo Antonio
Published: April 2019

Monitoring of rotor temperature in permanent magnet synchronous machines (PMSM) is of great importance as high temperature could cause partial or even irreversible demagnetisation of the permanent magnets (PMs). Rotor temperature measurement unfortunately is particularly difficult in practice, since it is difficult to access temperature sensors on a rotating shaft. Nevertheless, rotor temperature can be obtained indirectly with the information of rotor magnet flux linkage, as PM remanence decreases with rotor temperature. Here, a simple and relatively accurate method for online estimation of PM flux linkage is presented, based on the measurement of current response to the standard space‐vector pulse width modulation (SV‐PWM). This method uses the already‐existing PWM voltage as the excitation signal in order to avoid any form of signal injection which produces undesirable disturbance to the system. Knowledge of machine parameters, such as inductances which may vary due to saturation, is not required. The proposed methodology has been verified in real‐time simulation.
Evaluation of an un‐regulated input isolated DC–DC converter using WBG devices
Authors: Ramachandran Rakesh , Nymand Morten
Published: April 2019

The paper presents the design and analysis of an un‐regulated isolated DC–DC converter using wide band gap (WBG) devices for low‐voltage, high current applications. Un‐regulated isolated DC–DC converter uses a passive rectifier stage at the front end to connect to the utility grid. This will have a voltage stress of 480–780 V DC at the input of the isolated DC–DC converter. For the evaluation, SiC devices are used at the primary side and GaN devices at the secondary side of the converter. Later on the conclusion, a regulated isolated DC–DC converter, which uses an active PFC at the front‐end, will be recommended for having less chip area utilisation, less components and efficient magnetics as far as DC–DC converter is concerned.
Investigation of wire insulation for high‐temperature motor windings
Authors: Tshiloz Kavul , Smith Alexander Charles , Tuohy Paul Michael , Feehally Tom
Published: April 2019

There is a strong interest in the development of high‐temperature electrical machines, both from academic research and industrial consumers. Conventional electrical machines cannot operate much beyond 250° C, and this limits their application in certain sectors such as oil, gas, and aerospace. The key technology for high‐temperature operation is high‐temperature wire insulation systems for the motor windings. This study presents an experimental study on the temperature dependence of the wire insulation resistance of a standard Class H (180°C) enamel wire, a high‐temperature MAGNETEMP CA‐200 wire, a photonis glass‐coated wire, a mica‐taped VonRoll SK650 wire, a ceramic‐based CERAFIL500 wire, and a newly developed S‐2 glass‐fibre insulated wire. The results show that motor operation above ∼300°C for any length of time using conventional polymer‐based wire is difficult. It is possible, however, to operate motors up to 600°C using inorganic insulation coatings. The new wire using the S‐2 glass‐fibre insulation performed very well showing good insulation resistance up to 600°C: excellent flexibility and robustness, capable of very small bend diameters, and with packing factors almost identical to the conventional copper wire.
Robust AVR design for the synchronous generator
Authors: Ghamri Lamyaa Y. , Awadh Hamda , Al Shamsi Najla , AlKhateri Saeed , Khurram Adil , Rehman Habibur
Published: April 2019

Conventional automatic voltage regulator (AVR) schemes use thyristor‐based rectifiers in which the generator field voltage is varied by changing the thyristor's firing angle. The conventional AVR has been known to cause voltage sags and extended under‐voltages, especially under fault conditions. Several control schemes such as digital proportional–integral–derivative (PID) controllers, adaptive control schemes, and intelligent control schemes have been proposed in the literature. However, these schemes increase the complexity of the system. This work proposes a DC−DC converter‐based AVR as an alternative to the rectifier‐controlled AVR. The DC−DC converter is arranged in step‐down (buck‐type) configuration. The DC−DC converter uses metal‐oxide‐semiconductor field‐effect transistor/insulated‐gate bipolar transistors and has a faster response than the thyristors, thereby resulting in faster and precise control of the generator field voltage. The DC−DC converter is connected to the field circuit of the generator, and the terminal voltage of the generator is regulated by a PI controller by varying the converter duty cycle to control the generator field voltage. Simulation and experimental investigation has shown that the proposed scheme exhibits a better transient response and is robust under DC input voltage variation and generator load changes.
Performance of multi‐stage axial‐flux machines with MMEs
Authors: Spargo Anthony James
Published: April 2019

This study covers the investigation into the reduction of rare‐earth magnets in a permanent magnet (PM) machine via the use of multiple rotors to enable a PM generator to be comprised of mixed magnetic elements, hereafter referred to as MME, by substituting ferrite materials into some rotors. The particular machine covered in this paper featured four rotors, with two on the external sides and two inside, along with a trio of stators interlaced between the rotors. The efficiency, power, and cost of this machine are compared herein to explore available benefits of such a configuration as described. It was shown from the finite element analysis results that there was a clear benefit to using cheap ferrite materials in some rotors but not all, allowing for a huge cost decrease while only a small decrease in efficiency. The machine's purpose was for use in a low speed, direct‐drive, wind turbine. Therefore, the rated operating speed was required to be very low and was chosen to be 180 RPM which meant 40 poles were needed on the rotors to achieve 10 kVA at 60 Hz.
Impact of DC protection strategy of large HVDC network on frequency response of the connected AC system
Authors: Zhou Ding , Rahman Md Habibur , Xu Lie , Wang Yi
Published: April 2019

Integration of renewable energy generations requires the transmission of bulky power over long distance, and high‐voltage direct current (HVDC) transmission systems become a more preferable choice compared to conventional HVAC systems. For HVDC systems, one of the important concerns is the DC protection strategy which can significantly impact on the connected AC system performance, e.g. system frequency. The maximum loss‐of‐infeed for a AC network is highly dependent on the duration of the power outage, and the impacts of DC fault protection arrangements which result in different speed of power restoration on the connected AC system, on the system frequency, have not been properly understood. Different DC protection arrangements using DC disconnectors, fast and slow DC circuit breakers on frequency response of the connected AC networks are investigated. A three‐terminal meshed HVDC system is studied to demonstrate system behaviour during DC faults.
Probabilistic adaptive model predictive power pinch analysis (PoPA) energy management approach to uncertainty
Authors: Bassey Etim Nyong‐Bassey , Giaouris Damian , Patsios Haris , Gadoue Shady , Papadopoulos Athanasios I. , Seferlis Panos , Voutetakis Spyros , Papadopoulou Simira
Published: April 2019

This paper proposes a probabilistic power pinch analysis (PoPA) approach based on Monte–Carlo simulation (MCS) for energy management of hybrid energy systems uncertainty. The systems power grand composite curve is formulated with the chance constraint method to consider load stochasticity. In a predictive control horizon, the power grand composite curve is shaped based on the pinch analysis approach. The robust energy management strategy effected in a control horizon is inferred from the likelihood of a bounded predicted power grand composite curve, violating the pinch. Furthermore, the response of the system using the energy management strategies (EMS) of the proposed method is evaluated against the day‐ahead (DA) and adaptive power pinch strategy.
Continuous demagnetisation assessment for triple redundant nine‐phase fault‐tolerant permanent magnet machine
Authors: Shi Yanwen , Wang Jiabin
Published: April 2019

In this study, the risk of partial irreversible demagnetisation of a triple redundant, nine‐phase fault tolerant machine based on permanent‐magnet‐assisted synchronous reluctance machine topology has been comprehensively assessed under various faults, including the worst case scenario when the applied voltage vector is in the opposite direction of the back electromotive force due to sensing and inverter control failure, by employing a continuous demagnetisation model. The dynamic response during fault transients and the post‐demagnetisation performance, such as the demagnetisation distribution, reduction in the back EMF and torque, will also be analysed and compared.
Workforce Development for Ultra-High Performance Concrete
Authors: McMurry Grace , Weldon Brad , Newtson Craig
Published: April 2019

Ultra-high performance concrete (UHPC) is a cementitious material with a dense microstructure that contributes to high compressive strengths as well as enhanced durability properties. UHPC also possesses significant post-cracking strength and ductility due to the addition of fibers. These characteristics produce a material that provides advantages over conventional concrete; however, high costs attributed to materials and production, lack of industry familiarity and knowledge, and the absence of standardized design procedures have impeded its wide-spread use. To help disseminate knowledge on UHPC, the first of two workforce development symposiums on UHPC was held on April 17 – 18, 2018 in Las Cruces, New Mexico. The symposium consisted of presentations and hands-on demonstrations to introduce UHPC and distribute the findings of almost a decade of research conducted in New Mexico to a diverse audience including members of the New Mexico Department of Transportation, contractors, designers, researchers, and concrete suppliers.
Evaluation of Strains at the Bottom of the Asphalt Base Layer of a Semi-Rigid Pavement Under a Class 6 Vehicle
Authors: Talebsafa Mohsen , Romanoschi Stefan A. , Papagiannakis Athanassios T. , Popescu Constantin
Published: April 2019

A newly constructed pavement on US-287 near Mansfield, TX was instrumented with gauges installed at the bottom of the asphalt concrete base layer to measure the longitudinal and transverse strains developed under a test vehicle. The finite element program Abaqus was used to compute the strains at the location of the gauges; they were found in good agreement with the measured strains. The research showed that the strains under the steering axle were of similar magnitude as the strains under the rear tandem axle. The measured transverse strains were in general slightly bigger than the corresponding longitudinal strains, while the finite element model computed higher strains in the longitudinal direction. These findings suggest the need to account for the strain responses from the steering axle of trucks and to account for both the longitudinal and the transverse strains when computing the fatigue damage induced by trucks.
Versorgung von Patienten mit Kohlenmonoxidvergiftung
Authors: Lenard Daniela , Busch Hans-Jörg , Staps Enrico
Published: April 2019

Kohlenmonoxid ist ein ubiquitär vorkommendes Gas und findet weitreichend Anwendung. Kohlenmonoxidvergiftungen sind gerade im präklinischen Umfeld eine diagnostische Herausforderung, dabei mit mehreren Tausend Klinikvorstellungen im Jahr ein relevantes Krankheitsbild für den Rettungs- und Notarztdienst. Der Beitrag stellt die Versorgung von Patienten mit CO-Vergiftung anhand eines Fallbeispiels vor.
Hochintensives Intervalltraining (HIIT) und Typ-2-Diabetes mellitus
Authors: Brinkmann Christian
Published: April 2019

Hochintensives Intervalltraining (HIIT) kann eine zeitsparende Alternative zu einem Training mit moderat-intensiv kontinuierlichen Sporteinheiten für Patientinnen und Patienten mit Typ-2-Diabetes mellitus mit guten bis überlegenen Effekten auf die kardiorespiratorische Fitness, glykämische Kontrolle und andere Variablen (z. B. oxidativer Stress, Endothelfunktion) sein. Ein sportmedizinischer Check-up vor Aufnahme des Trainings sollte verpflichtend sein, um kardiovaskuläre Risiken zu reduzieren. Bei schweren Folgeerkrankungen wie fortgeschrittenen Retinopathien oder autonomen Neuropathien ist grundsätzlich von HIIT abzuraten. Es ist noch weiter zu klären, wie sicher HIIT ist und wie gut es die Typ-2-Diabetes-Patientinnen und -Patienten zum Sporttreiben motivieren kann.
Die praktische Implementierung von Hochintensivem Intervalltraining (HIIT) in sporttherapeutischen Maßnahmen bei Kindern mit Aufmerksamkeitsdefizit / Hyperaktivitätsstörung (ADHS)
Authors: Meßler Carolin Friederike
Published: April 2019

In diesem Beitrag werden praktische Umsetzungsmöglichkeiten eines (hoch-) intensiven Intervalltrainings (HIIT) für Kinder mit Aufmerksamkeitsdefizit / Hyperaktivitätsstörung (ADHS) präsentiert. Zudem wird vermittelt, welche entscheidende Rolle Sporttherapeuten durch ihr Bindungsverhalten mit Kindern einnehmen und wie sie in schwierigen Situationen problemlösend handeln können.
Das Stimmliche Selbstkonzept bei 230 Patienten nach
Kopf-Hals-Tumortherapie
Authors: Lehnert Bernhard , Balzer Jasmin , Grafmans Daniel
Published: April 2019

Einleitung Der ‚Fragebogen zur Erfassung des Stimmlichen Selbstkonzepts
(FESS)‘, von Nusseck et al 2015, untersucht das Stimmliche Selbstkonzept in 3
Skalen. Einblicke in das Stimmliche Selbstkonzept könnten helfen, den
Beratungsbedarf von Patienten hinsichtlich der Stimme besser zu beurteilen und
sowohl die Patientenberatung als auch klinische Entscheidungen in der
Tumortherapie beeinflussen. Bisher wurden aber noch keine Vergleichswerte für
die drei Skalen publiziert, die an Kopf-Hals-Tumor-Patienten erhoben wurden.

Material und Methoden 230 Patienten unserer Tumornachsorgesprechstunde
füllten den Fragebogen aus. Wir beschreiben die Verteilung der so erhobenen
Werte und untersuchen den Einfluss von Alter und Geschlecht.

Ergebnisse Die Verteilung der Skalenwerte ist gut. Der Einfluss von Alter
und Geschlecht ist allenfalls geringfügig, so dass unsere Werte als erste
Vergleichswerte unabhängig von Alter und Geschlecht verwendet werden können.

Schlussfolgerungen Der FESS ist für Patienten nach Kopf-Hals-Tumortherapie
anwendbar und erste Vergleichswerte zur Einordnung individueller Testergebnisse
liegen hiermit vor.
Sonographic Estimated Fetal Weight and Cesarean Delivery among Nulliparous Women with Obesity
Authors: Dude Annie , Davis Berkley , Delaney Katie , Yee Lynn
Published: April 2019

Objective This study was aimed to examine the association between having an ultrasound estimate of fetal weight (US-EFW) and mode of delivery among obese women.

Study Design A retrospective cohort study of nulliparous women with a body mass index of ≥ 35 kg/m2 who delivered term singleton gestations. We examined whether having had an US-EFW within 35 days of delivery, or an US-EFW ≥ 90th percentile for gestational age, was associated with intrapartum cesarean delivery.

Results Of 2,826 women, 22.5% (n = 636) had an US-EFW within 35 days of delivery. Having an US-EFW was associated with increased frequency of cesarean (43.1% for those with an US-EFW versus 30.0% for those without, p < 0.001); this finding persisted when controlling for confounders (adjusted odds ratio [aOR] 1.48, 95% confidence interval [CI] 1.21–1.81). Of the 636 women with an US-EFW, 22.5% (n = 143) had an US-EFW ≥ 90th percentile for gestational age, which was associated with increased frequency of an intrapartum cesarean (60.8% for those with an US-EFW ≥ 90th percentile vs. 37.9% for those with an US-EFW of < 90th percentile, p < 0.001), even when accounting for confounders (aOR = 1.78, 95% CI: 1.10–2.87).

Conclusion The presence of an US-EFW among nulliparous obese women was associated with undergoing intrapartum cesarean delivery.
Engineering heat transport in nanoparticle-in-alloy composites: The role of Mie scattering
Authors: Feser Joseph P.
Published: April 2019

Previous work toward engineering lower thermal conductivity of nanoparticle-in-alloy semiconductor composites have indicated that optimal nanoparticle sizes should lie between the Rayleigh and geometric phonon scattering regimes (i.e. the Mie regime); yet, phonon scattering models that are accurate in the Mie regime have never been employed to investigate the thermal transport. Here, we exploit exact solutions from continuum mechanics that separately treat longitudinal and transverse phonon scattering from nanoparticles across a wide spectrum of wavelengths, including the Rayleigh, Mie, and geometric scattering regimes. The solutions intrinsically account for material contrast effects from density and both normal and shear elastic constants. We find that consideration of Mie scattering effects drastically alters the material selection and particle sizing process for optimal nanocomposites. In particular, a previously unreported inter-relationship between density and elastic contrast is reported: in the Mie regime, a suppression of the scattering cross section is found in cases where the sound speeds of the matrix and nanoparticle are closely matched. This suppression can extend the transition wavelength to geometric scattering by more than an order-of-magnitude, with severe effects to thermal transport. We explore how these considerations change the optimal sizing of nanoparticles for metal/semiconductor composites, with specific application to the experimentally significant case of InGaAs composites.
An efficient terahertz polarization converter with highly flexible tunability over an ultra-broad bandwidth
Authors: Luo X. Q. , Tan Z. Y. , Wan W. J. , Wang C. , Cao J. C.
Published: April 2019

The polarization control and conversion of electromagnetic waves is of vital importance in many practical applications and experimental systems. For terahertz waves that cover a broad frequency range of 0.3–10 THz, an operation with high spectral tunability is essential, especially for spectroscopic applications. In this paper, we propose a very simple yet efficient experimental apparatus to convert a linearly polarized beam into a circularly polarized or even an elliptically polarized beam, with high efficiency (>90%) and ultrabroad bandwidth (0.3–10 THz) tunability in the terahertz region. The proposed polarization converter, consisting of only a wire-grid polarizer and a mirror, is convenient and flexible to use in the experimental setup in the laboratory. We expect that it can find broad applications in advanced spectroscopy systems like terahertz ellipsometry where an elliptically polarized beam is needed.
Controlling the trade-off between spikelet number and grain filling: the hierarchy of starch synthesis in spikelets of rice panicle in relation to hormone dynamics
Authors: Panigrahi Rashmi , Kariali Ekamber , Panda Binay Bhusan , Lafarge Tanguy , Mohapatra Pravat Kumar
Published: April 2019

The advent of dwarf statured rice varieties enabled a major breakthrough in yield and production, but raising the ceiling of genetically determined yield potential even further has been the breeding priority. Grain filling is asynchronous in the rice panicle; the inferior spikelets particularly on secondary branches of the basal part do not produce grains of a quality suitable for human consumption. Of the various strategies being considered, the control of ethylene production at anthesis has been a valuable route to potentially enhance genetic yield level of rice. The physiology underlying spikelet development has revealed spikelet position-specific ethylene levels determine the extent of grain filling, with higher levels resulting in ill-developed spikelet embodying poor endosperm starch content. To break the yield barrier, breeders have increased spikelet number per panicle in new large-panicle rice plants. However, the advantage of panicles with numerous spikelets has not resulted in enhanced yield because of poor filling of inferior spikelets. High spikelet number stimulates ethylene production and downgrading of starch synthesis, suggesting a trade-off between spikelet number and grain filling. High ethylene production in inferior spikelets suppresses expression of genes encoding endosperm starch synthesising enzymes. Hence, ethylene could be a retrograde signal that dictates the transcriptome dynamics for the cross talk between spikelet number and grain filling in the rice panicle, so attenuation of its activity may provide a solution to the problem of poor grain filling in large-panicle rice. This physiological linkage that reduces starch biosynthesis of inferior kernels is not genetically constitutive and amenable for modification through chemical, biotechnological, surgical and allelic manipulations. Studies on plant genotypes with different panicle architecture have opened up possibilities of selectively improving starch biosynthesis of inferior spikelets and thereby increasing grain yield through a physiological route.
Systems thinking as a pathway to global warming beliefs and attitudes through an ecological worldview
Authors: Ballew Matthew T. , Goldberg Matthew H. , Rosenthal Seth A. , Gustafson Abel , Leiserowitz Anthony
Published: April 2019

Prior research has found that systems thinking, the tendency to perceive phenomena as interconnected and dynamic, is associated with a general proenvironmental orientation. However, less is known about its relationship with public understanding of climate change and/or whether this relationship varies across people with different political views. Because climate change is a highly politicized issue, it is also important to understand the extent to which systems thinking can foster acceptance of climate science across political lines. Using an online sample of US adults (
n
= 1,058), we tested the degree to which systems thinking predicts global warming beliefs and attitudes (e.g., believing that global warming is happening, that it is human-caused, etc.), independent of an ecological worldview (i.e., the New Ecological Paradigm). We found that although systems thinking is positively related to global warming beliefs and attitudes, the relationships are almost fully explained by an ecological worldview. Indirect effects of systems thinking are consistently strong across political ideologies and party affiliations, although slightly stronger for conservatives and Republicans than for liberals and Democrats, respectively. We did not find evidence of the converse: Systems thinking does not seem to mediate the relationship between an ecological worldview and global warming beliefs and attitudes. Together, these findings suggest that systems thinking may support the adoption of global warming beliefs and attitudes indirectly by helping to develop an ecological ethic that people should take care of and not abuse the environment.
Parallel spatial channels converge at a bottleneck in anterior word-selective cortex
Authors: White Alex L. , Palmer John , Boynton Geoffrey M. , Yeatman Jason D.
Published: April 2019

In most environments, the visual system is confronted with many relevant objects simultaneously. That is especially true during reading. However, behavioral data demonstrate that a serial bottleneck prevents recognition of more than one word at a time. We used fMRI to investigate how parallel spatial channels of visual processing converge into a serial bottleneck for word recognition. Participants viewed pairs of words presented simultaneously. We found that retinotopic cortex processed the two words in parallel spatial channels, one in each contralateral hemisphere. Responses were higher for attended than for ignored words but were not reduced when attention was divided. We then analyzed two word-selective regions along the occipitotemporal sulcus (OTS) of both hemispheres (subregions of the visual word form area, VWFA). Unlike retinotopic regions, each word-selective region responded to words on both sides of fixation. Nonetheless, a single region in the left hemisphere (posterior OTS) contained spatial channels for both hemifields that were independently modulated by selective attention. Thus, the left posterior VWFA supports parallel processing of multiple words. In contrast, activity in a more anterior word-selective region in the left hemisphere (mid OTS) was consistent with a single channel, showing (
i
) limited spatial selectivity, (
ii
) no effect of spatial attention on mean response amplitudes, and (
iii
) sensitivity to lexical properties of only one attended word. Therefore, the visual system can process two words in parallel up to a late stage in the ventral stream. The transition to a single channel is consistent with the observed bottleneck in behavior.
Childhood trauma history is linked to abnormal brain connectivity in major depression
Authors: Yu Meichen , Linn Kristin A. , Shinohara Russell T. , Oathes Desmond J. , Cook Philip A. , Duprat Romain , Moore Tyler M. , Oquendo Maria A. , Phillips Mary L. , McInnis Melvin , Fava Maurizio , Trivedi Madhukar H. , McGrath Patrick , Parsey Ramin , Weissman Myrna M. , Sheline Yvette I.
Published: April 2019

Significance

The primary finding in this study was the dramatic primary association of brain resting-state network (RSN) connectivity abnormalities with a history of childhood trauma in major depressive disorder (MDD). Even though participants in this study were not selected for a history of trauma and the brain imaging took place decades after trauma occurrence, the scar of prior trauma was evident in functional dysconnectivity. In addition to childhood trauma, dimensions of MDD symptoms were related to abnormal network connectivity. Further, we found that a network model of MDD described within- and between-network connectivity differences from controls in multiple RSNs, including the default mode network, frontoparietal network, and attention and sensory systems.
Comparison of the musculoskeletal effects of different iso‐inertial resistance training modalities: Flywheel vs. electric‐motor
Authors: Maroto‐Izquierdo Sergio , Fernandez‐Gonzalo Rodrigo , Magdi Hashish R. , Manzano‐Rodriguez Saul , González‐Gallego Javier , De Paz José a.
Published: April 2019

This study aimed to analyse whether increasing the eccentric overload (EO) during resistance training, in terms of range of motion and/or velocity using an electric‐motor device, would induce different muscle adaptations than conventional flywheel‐EO resistance training. Forty physically active university students (21.7 ± 3.4 years) were randomly placed into one of the three training groups (EX1, EX2, FW) and a control group without training (n = 10 per group). Participants in the training groups completed 12 sessions (4 sets of 7 repetitions) of iso‐inertial single‐leg squat training over 6 weeks for the dominant leg. Resistance was generated either by an electric‐motor device at two different velocities for the eccentric phase; 100% (EX1) or 150% (EX2) of concentric speed, or by a conventional flywheel device (FW). Thigh lean tissue mass, unilateral leg press one‐repetition maximum (1‐RM), unilateral muscle power at different percentages of the 1‐RM and bilateral/unilateral vertical jump were assessed before and after the 6‐week training. There were significant (p < 0.05–0.001) main effects of time in the 3 training groups, indicating increased thigh lean tissue mass (2.5–5.8%), 1‐RM load (22.4–30.2%), vertical jump performance (9.1–32.9%) and muscle power (8.8–21.7%), without differences across experimental groups. Participants in the control group did not improve any of the variables measured. In addition, EX2 showed greater gains in eccentric average peak power during training than EX1 and FW (p < 0.001). Despite the different EO offered, 6 weeks of resistance training using flywheel or electric‐motor devices induced similar significant gains in muscle mass, strength, muscle power and vertical jump.
Improvement of Working Memory is a Mechanism for Reductions in Delay Discounting Among Mid-Age Individuals in an Urban Medically Underserved Area
Authors: Felton Julia W , Collado Anahi , Ingram Katherine M , Doran Kelly , Yi Richard
Published: April 2019

Background

Delay discounting, or the tendency to devalue rewards as a function of their delayed receipt, is associated with myriad negative health behaviors. Individuals from medically underserved areas are disproportionately at risk for chronic health problems. The higher rates of delay discounting and consequent adverse outcomes evidenced among low-resource and unstable environments suggest this may be an important pathway to explain health disparities among this population.

Purpose

The current study examined the effectiveness of a computerized working memory training program to decrease rates of delay discounting among residents of a traditionally underserved region.

Methods

Participants (N = 123) were recruited from a community center serving low income and homeless individuals. Subjects completed measures of delay discounting and working memory and then took part in either an active or control working memory training.

Results

Analyses indicated that participants in the active condition demonstrated significant improvement in working memory and that this improvement mediated the relation between treatment condition and reductions in delay discounting.

Conclusions

Results suggest that a computerized intervention targeting working memory may be effective in decreasing rates of delay discounting in adults from medically underserved areas (ClinicalTrials.gov number NCT03501706).
Accounting for ambiguity in ancestral sequence reconstruction
Authors: Oliva A , Pulicani S , Lefort V , Bréhélin L , Gascuel O , Guindon S
Published: April 2019

Motivation

The reconstruction of ancestral genetic sequences from the analysis of contemporaneous data is a powerful tool to improve our understanding of molecular evolution. Various statistical criteria defined in a phylogenetic framework can be used to infer nucleotide, amino-acid or codon states at internal nodes of the tree, for every position along the sequence. These criteria generally select the state that maximizes (or minimizes) a given criterion. Although it is perfectly sensible from a statistical perspective, that strategy fails to convey useful information about the level of uncertainty associated to the inference.

Results

The present study introduces a new criterion for ancestral sequence reconstruction, the minimum posterior expected error (MPEE), that selects a single state whenever the signal conveyed by the data is strong, and a combination of multiple states otherwise. We also assess the performance of a criterion based on the Brier scoring scheme which, like MPEE, does not rely on any tuning parameters. The precision and accuracy of several other criteria that involve arbitrarily set tuning parameters are also evaluated. Large scale simulations demonstrate the benefits of using the MPEE and Brier-based criteria with a substantial increase in the accuracy of the inference of past sequences compared to the standard approach and realistic compromises on the precision of the solutions returned.

Availability and implementation

The software package PhyML (https://github.com/stephaneguindon/phyml) provides an implementation of the Maximum A Posteriori (MAP) and MPEE criteria for reconstructing ancestral nucleotide and amino-acid sequences.
A learning-based framework for miRNA-disease association identification using neural networks
Authors: Peng Jiajie , Hui Weiwei , Li Qianqian , Chen Bolin , Hao Jianye , Jiang Qinghua , Shang Xuequn , Wei Zhongyu
Published: April 2019

Motivation

A microRNA (miRNA) is a type of non-coding RNA, which plays important roles in many biological processes. Lots of studies have shown that miRNAs are implicated in human diseases, indicating that miRNAs might be potential biomarkers for various types of diseases. Therefore, it is important to reveal the relationships between miRNAs and diseases/phenotypes.

Results

We propose a novel learning-based framework, MDA-CNN, for miRNA-disease association identification. The model first captures interaction features between diseases and miRNAs based on a three-layer network including disease similarity network, miRNA similarity network and protein-protein interaction network. Then, it employs an auto-encoder to identify the essential feature combination for each pair of miRNA and disease automatically. Finally, taking the reduced feature representation as input, it uses a convolutional neural network to predict the final label. The evaluation results show that the proposed framework outperforms some state-of-the-art approaches in a large margin on both tasks of miRNA-disease association prediction and miRNA-phenotype association prediction.

Availability and implementation

The source code and data are available at https://github.com/Issingjessica/MDA-CNN.

Supplementary information

Supplementary data are available at Bioinformatics online.
Biomedical image augmentation using Augmentor
Authors: Bloice Marcus D , Roth Peter M , Holzinger Andreas
Published: April 2019

Motivation

Image augmentation is a frequently used technique in computer vision and has been seeing increased interest since the popularity of deep learning. Its usefulness is becoming more and more recognized due to deep neural networks requiring larger amounts of data to train, and because in certain fields, such as biomedical imaging, large amounts of labelled data are difficult to come by or expensive to produce. In biomedical imaging, features specific to this domain need to be addressed.

Results

Here we present the Augmentor software package for image augmentation. It provides a stochastic, pipeline-based approach to image augmentation with a number of features that are relevant to biomedical imaging, such as z-stack augmentation and randomized elastic distortions. The software has been designed to be highly extensible meaning an operation that might be specific to a highly specialized task can easily be added to the library, even at runtime. Although it has been designed as a general software library, it has features that are particularly relevant to biomedical imaging and the techniques required for this domain.

Availability and implementation

Augmentor is a Python package made available under the terms of the MIT licence. Source code can be found on GitHub under https://github.com/mdbloice/Augmentor and installation is via the pip package manager (A Julia version of the package, developed in parallel by Christof Stocker, is also available under https://github.com/Evizero/Augmentor.jl).
Genetic differentiation predicts body size divergence between island and mainland populations of common wall lizards (Podarcis muralis)
Authors: Uller Tobias , Laakkonen Hanna , Michaelides Sozos , While Geoffrey M , Coulon Aurélie , Aubret Fabien
Published: April 2019

Small-bodied vertebrates sometimes evolve gigantism on islands, but there is a lack of consistent association with ecological factors or island characteristics. One possible reason is that, even if the ecological conditions are right, body size might fail to diverge on islands that were isolated recently or if there is gene flow between islands and the mainland. We studied body size, ventral colour polymorphism and genetic structure across nine islands and adjacent mainland populations of common wall lizards (Podarcis muralis) off the western coast of France. Population genetic data suggested that island populations might have maintained gene flow after their geographical isolation from the mainland. Island lizards were larger and heavier than mainland lizards on average, but the extent of gigantism varied substantially between islands. Island size and distance from the mainland were poor predictors of body size, but lizards from populations that were highly genetically differentiated from the mainland were larger than lizards from less differentiated populations. Colour morphs that were rare on the mainland tended to be more common on islands. We propose that genetic isolation or bottlenecks promote body size evolution in island lizards, which makes it challenging to identify ecological causes of island gigantism without complementary genetic information.
Sleep and risk of parkinsonism and Parkinson’s disease: a population-based study
Authors: Lysen Thom S , Darweesh Sirwan K L , Ikram M Kamran , Luik Annemarie I , Ikram M Arfan
Published: April 2019

While specific sleep disorders are known to precede Parkinson’s disease, it remains unclear how sleep disturbances in the general population affect risk. Lysen et al. report that poor sleep quality and short sleep duration, and their deterioration over time, are associated with increased risk of parkinsonism, including Parkinson’s disease.