bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Transmitting Power Control Method without Signal Communication for Wireless Power Transfer via Magnetic Resonance Coupling
Authors: GUNJI DAISUKE , IMURA TAKEHIRO , FUJIMOTO HIROSHI 
Published: January 2017

SUMMARYWireless power transfer (WPT) via magnetic resonance coupling has been widely studied for vehicle applications, particularly the stationary and dynamic charging of electric vehicles. Our research group previously proposed a wireless in‐wheel motor to improve the reliability and safety of in‐wheel motors. Transmit power control is necessary to achieve stable WPT. We proposed a control method that uses a feedforward controller on the primary side and a feedback controller on the secondary side. However, the control method may cause shortfalls in the transmission power owing to modeling error, coupling coefficient variation, and signal communication delay. In this paper, we propose a novel feedback control method for the primary side based on conversion ratio estimation. The effectiveness of the proposed method was verified by simulations and experiments on the load current control of a constant voltage load and load voltage control of a constant power load.
Estimation and Kinetic Modeling of Human Arm using Wearable Robot Arm
Authors: YAMAZAKI TAKAHIRO , SAKAINO SHO , TSUJI TOSHIAKI 
Published: January 2017

SUMMARYThis paper describes an estimation method for the physical parameters of human arms. The parameters are used in the medical and kinematic analysis fields. Personal differences are important, but some of the conventional methods do not consider personal differences pertaining to inertia in viscoelasticity muscular strength measurements. The remaining conventional methods that consider personal differences require precise measurement devices. The proposed method realizes kinetics modeling and identification of the friction and inertia including the off‐diagonal parameters of human arms by using wearable robots. First, wearable robots are multi‐input devices. In addition, the actuators of wearable robots can be located near human joints and can input M‐sequence torque. Therefore, wearable robots can input signals having a high signal‐to‐noise ratio and ensuring persistently exciting characteristics in each human joint. By employing multi‐input characteristics, the proposed method can reduce patients’ burden by shortening the amount of time for estimation. In addition, we verify the accuracy of the estimated parameters by comparing the responses of the actual machine with those obtained by simulation.
Rectification Methods to Increase Harvested Energy in Vibration Generation Using Piezoelectric Elements
Authors: TANAKA TORU , AONUMA TOMOYA , NATORI KENJI , SATO YUKIHIKO 
Published: January 2017

SUMMARYWe studied vibration power generation using piezoelectric elements in order to determine effective rectification methods to increase harvested energy from vibration power generation systems. First, we experimentally clarified the output characteristics of two kinds of passive rectification methods for vibration power generation systems. Then, an appropriate rectification method for various kinds of loads was studied. In order to increase the harvested power from an integrated vibration power generation system with multiple piezoelectric elements, we considered an appropriate circuit structure for connecting multiple piezoelectric elements. The effectiveness was verified experimentally.
Cathodic Stripping Voltammetric Determination of Cerium Using Indium Tin Oxide (ITO)
Authors: Ojo Kolade , Zhao Daoli , Rusinek Cory A. , Pixley Sarah K. , Heineman William R. 
Published: January 2017

AbstractDue to its numerous applications in the field of metallurgy and its role as an alloying element for slowing down the biodegradation of pure magnesium typically known to have very low corrosion resistance, the need to develop simple and inexpensive methods for determination of cerium is important. Ce3+ was determined by cathodic stripping voltammetry (CSV) using Osteryoung square‐wave voltammetry (OSWV) for the stripping step. Indium tin oxide (ITO) was used as the working electrode because of its very good positive potential range with smooth background current. Under optimized conditions, the calibration plot was linear in the concentration range of 100 nM to 700 nM Ce3+. A calculated detection limit of 5.8 nM was found for a 5 min deposition time at ITO based on the 3σ method. Interference from selected metal ions was also examined, and no significant interferences were observed. The good selectivity of this sensor makes it a good candidate for practical applications such as monitoring Ce3+ released into solution during the biodegradation of Mg−Ce alloys being developed for resorbable biomedical implants.
Very Small Inverted Hysteresis in Vacuum‐Deposited Mixed Organic–Inorganic Hybrid Perovskite Solar Cells
Authors: Erdenebileg Enkhtur , Scholz Lauren E. , Hofacker Andreas , Koerner Christian , Leo Karl 
Published: January 2017

AbstractPerovskite solar cells (PSCs) have attracted great interest over the past few years due to their outstanding power conversion efficiencies. However, operational stability still needs to be improved for broad commercial application. A commonly observed phenomenon for PSCs is hysteresis in their current–voltage characteristics, which has been suggested to be related to issues with long‐term stability. A thorough understanding of the processes involved in hysteresis may also guide the way to further improving the cells’ efficiencies. We fabricate planar p–i–n organic–inorganic hybrid PSCs using three different organic transport layer architectures by vacuum deposition and measured their hysteresis and long‐term stability behavior. Our results show that vacuum‐deposited PSCs show much weaker hysteresis than in previous studies, where many types of PSCs were involved. For our devices, we also report an inverted hysteresis, where efficiency is somewhat higher for a voltage sweep from short circuit to forward‐bias conditions than for the reverse sweep at lower scan rates, which has not commonly been observed in previous studies of PSCs. Finally, we observe that up to 94 % of the initial power conversion efficiency of the encapsulated devices remained after storage in the dark for two months.
Performance Improvement of an Inhomogeneous Cathode by Infiltration
Authors: Seyed‐Vakili S. V. , Graves C. R. , Babaei A. , Heshmati‐Manesh S. , Mogensen M. B. 
Published: January 2017

AbstractThe performance of solid oxide fuel cells (SOFCs) is considerably influenced by the microstructure and chemical composition of cathode materials. Porous La0.85Sr0.15FeO3–Ce0.9Gd0.1O2 composite electrodes were infiltrated by La0.6Sr0.4CoO3 and La0.6Sr0.4FeO3. The effects of infiltration loading, calcination temperature of infiltrated material and co‐infiltration of LSC and LSF were investigated using electrochemical impedance measurement, microstructural analysis, and high‐temperature X‐ray diffraction (HT‐XRD). A symmetrical cell two‐electrode configuration was used to examine the electrochemical performance of the electrodes. The electrochemical results revealed that the polarization resistance of the cathodes significantly was decreased by infiltration from 2.59 to 0.034 Ω cm2 measured at 670 °C. The best electrode performance was achieved at a calcination temperature of 770 °C. It was also found that infiltration of LSC improved the stability of the electrodes during 145 h of testing at 620 °C in air at open circuit voltage (OCV).
The use of instructional design guidelines to increase effectiveness of postpartum hemorrhage simulation training
Authors: de Melo Brena C.P. , Falbo Ana R. , Muijtjens Arno M.M. , van der Vleuten Cees P.M. , van Merriënboer Jeroen J.G. 
Published: January 2017

AbstractObjectiveTo compare learning outcomes of postpartum hemorrhage simulation training based on either instructional design guidelines or best practice.MethodsA pretest–post‐test non‐equivalent groups study was conducted among obstetrics and gynecology residents in Recife, Brazil, from June 8 to August 30, 2013. The instructional design group included 13 teams, whereas the best practice group included seven teams. A standardized task checklist was used for scenario analysis and the proportion of correctly executed tasks compared (post‐test minus pretest).ResultsThe instructional design group scored higher than the best practice group for total number of tasks completed (median difference 0.46 vs 0.17; P<0.001; effect size [r]=0.72). Similar results were observed for communication (median difference 0.56 vs 0.22; P=0.004; r=0.58), laboratory evaluation (median difference 0.83 vs 0.00; P<0.001; r=0.76), and mechanical management (median difference 0.25 vs –0.15; P=0.048; r=0.39). Speed of learning was also increased. The median differences were 0.20 for the instructional design group compared with 0.05 for the best practice group at 60 seconds (P=0.015; r=0.49), and 0.49 versus 0.26 (P=0.001; r=0.65) at 360 seconds.ConclusionThe use of simulation training for postpartum hemorrhage that was based on instructional design guidelines yielded better learning outcomes than did training based on best practice.
Similar but not consistent: Revisiting the pitfalls of measuring IgG subclasses with different assays
Authors: Ludwig‐Kraus Beatrice , Kraus Frank Bernhard 
Published: January 2017

BackgroundLaboratory quantification of IgG subclasses (IgGSc) is a well‐established second‐line tool for differential diagnosis of immune deficiencies. However, so far there is still no internationally approved standard available for IgGSc, and different assays are prone to produce divergent results. In this study, we evaluated the comparability and equivalence of two commercially available IgGSc assays, one being the Siemens IgGSc assay on a BN ProSpec analyzer and the other being The Binding Site (TBS) IgGSc assay on a Roche cobas c502 analyzer.MethodsWe analyzed a total of 50 patient plasma samples obtained over a 3‐month period with both IgGSc assays and compared the resulting data based and the CLSI EP09‐A3 method comparison guideline.ResultsDepending on the analyzed IgGSc type, the average relative differences in IgGSc concentration (g/L) between the two assays were considerable, starting with −13.5% for IgG1 and 11.3% for IgG2, over −47.3% for IgG4, and up to 52.9% for IgG3. Applying the assay‐specific reference intervals, the classification agreement (below, within, or above the reference range) ranged from 88% to 90% for the individual subclasses. However, only 68% of samples showed an overall classification agreement.ConclusionThe comparability of the two IgGSc assays proved to be limited and might be considered similar at best on the diagnostic level. Laboratory specialists as well as clinicians therefore should be cautious when using and interpreting IgGSc measurements obtained with different assays or analyzers.
Sleep‐disordered breathing in pediatric head and neck vascular malformations
Authors: Durr Megan L. , Meyer Anna K. , Kezirian Eric J. , Mamlouk Mark D. , Frieden Ilona J. , Rosbe Kristina W. 
Published: January 2017

ObjectivesTo determine the prevalence of sleep‐disordered breathing (SDB) symptoms among children with head and neck vascular malformations and to compare obstructive sleep apnea (OSA)‐18 scores between children with head and neck vascular malformations and children with non‐head and neck vascular malformations.Study DesignRetrospective cohort and prospective cross‐sectional studiesMethodsForty‐three pediatric subjects with head and neck vascular malformations evaluated at a tertiary‐care multidisciplinary vascular anomalies center were included in a retrospective cohort study. Eighty‐three consecutive pediatric subjects with vascular malformations evaluated at the same center were included in the prospective cross‐sectional study.ResultsIn the retrospective cohort study, 20 (47%) subjects with head and neck malformations had documented SDB symptoms. Of those with SDB symptoms, five (25%) required long‐term tracheotomy. The children with SDB symptoms had greater vascular malformation size, more extensive pharyngeal involvement, greater vascular malformation mass effect on airway, and closer proximity of malformation to airway when compared to children without SDB symptoms.For the prospective cross‐sectional study, 23% of pediatric subjects had malformations of the head and neck. Those with head and neck malformations had a higher OSA‐18 score and a lower overall quality of life (QOL) score when compared to subjects with non‐head and neck malformations.ConclusionNearly half of children with head and neck vascular malformations have SDB symptoms. Children with head and neck vascular malformations have a higher OSA‐18 score and lower overall QOL score when compared to children with non‐head and neck vascular malformations.Level of Evidence4. Laryngoscope, 127:2159–2164, 2017
Analysis of the effects of noise, DWI sampling, and value of assumed parameters in diffusion MRI models
Authors: Hutchinson Elizabeth B. , Avram Alexandru V. , Irfanoglu M. Okan , Koay C. Guan , Barnett Alan S. , Komlosh Michal E. , Özarslan Evren , Schwerin Susan C. , Juliano Sharon L. , Pierpaoli Carlo 
Published: January 2017

PurposeThis study was a systematic evaluation across different and prominent diffusion MRI models to better understand the ways in which scalar metrics are influenced by experimental factors, including experimental design (diffusion‐weighted imaging [DWI] sampling) and noise.MethodsFour diffusion MRI models—diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), mean apparent propagator MRI (MAP‐MRI), and neurite orientation dispersion and density imaging (NODDI)—were evaluated by comparing maps and histogram values of the scalar metrics generated using DWI datasets obtained in fixed mouse brain with different noise levels and DWI sampling complexity. Additionally, models were fit with different input parameters or constraints to examine the consequences of model fitting procedures.ResultsExperimental factors affected all models and metrics to varying degrees. Model complexity influenced sensitivity to DWI sampling and noise, especially for metrics reporting non‐Gaussian information. DKI metrics were highly susceptible to noise and experimental design. The influence of fixed parameter selection for the NODDI model was found to be considerable, as was the impact of initial tensor fitting in the MAP‐MRI model.ConclusionAcross DTI, DKI, MAP‐MRI, and NODDI, a wide range of dependence on experimental factors was observed that elucidate principles and practical implications for advanced diffusion MRI. Magn Reson Med 78:1767–1780, 2017. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Can Patel's τ accurately estimate directionality of connections in brain networks from fMRI?
Authors: Wang Yunzhi , David Olivier , Hu Xiaoping , Deshpande Gopikrishna 
Published: January 2017

PurposeInvestigating directional interactions between brain regions plays a critical role in fully understanding brain function. Consequently, multiple methods have been developed for noninvasively inferring directional connectivity in human brain networks using functional MRI (fMRI). Recent simulations by Smith et al. showed that Patel's τ, a method based on higher‐order statistics, was the best approach for inferring directional interactions from fMRI. Because simulations make restrictive assumptions about reality, we set out to verify this finding using experimental fMRI data obtained from a three‐region network in a rat model with electrophysiological validation.MethodsPrevious studies have shown that dynamic causal modeling can correctly estimate the directionality of this three‐region network; Granger causality can also work after the deconvolution of the hemodynamic response. Therefore, we set out to test the hypothesis that Patel's τ obtained from either raw or deconvolved fMRI data should correctly estimate the directionality of neuronal influences obtained from intracerebral electroencephalogram in this network.ResultsOur results indicate that the accuracy of network directionality estimated using Patel's τ was not better than chance.ConclusionFirst, our results highlight the necessity of experimental validation of simulation results. Second, it is unclear which brain mechanism is modeled by a directionality inferred from Patel's τ. Third, this study shows that a directional connection ascertained by different methods may mean different things and more experimental studies are needed for investigating the neuronal mechanisms underlying the direction of a connection in the brain ascertained by fMRI using different methods. M Magn Reson Med 78:2003–2010, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
Real‐time monitoring of tissue displacement and temperature changes during MR‐guided high intensity focused ultrasound
Authors: Bour Pierre , Marquet Fabrice , Ozenne Valéry , Toupin Solenn , Dumont Erik , Aubry Jean‐François , Lepetit‐Coiffe Matthieu , Quesson Bruno 
Published: January 2017

PurposeThe therapy endpoint most commonly used in MR‐guided high intensity focused ultrasound is the thermal dose. Although namely correlated with nonviable tissue, it does not account for changes in mechanical properties of tissue during ablation. This study presents a new acquisition sequence for multislice, subsecond and simultaneous imaging of tissue temperature and displacement during ablation.MethodsA single‐shot echo planar imaging sequence was implemented using a pair of motion‐encoding gradients, with alternated polarities. A first ultrasound pulse was synchronized on the second lobe of the motion‐encoding gradients and followed by continuous sonication to induce a local temperature increase in ex vivo muscle and in vivo on pig liver. Lastly, the method was evaluated in the brain of two volunteers to assess method's precision.ResultsFor thermal doses higher than the lethal threshold, displacement amplitude was reduced by 21% and 28% at the focal point in muscle and liver, respectively. Displacement value remained nearly constant for nonlethal thermal doses values. The mean standard deviation of temperature and displacement in the brain of volunteers remained below 0.8 °C and 2.5 µm.ConclusionThis new fast imaging sequence provides real‐time measurement of temperature distribution and displacement at the focus during HIFU ablation. Magn Reson Med 78:1911–1921, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
Quantitative ultrashort echo time imaging for assessment of massive iron overload at 1.5 and 3 Tesla
Authors: Krafft Axel J. , Loeffler Ralf B. , Song Ruitian , Tipirneni‐Sajja Aaryani , McCarville M. Beth , Robson Matthew D. , Hankins Jane S. , Hillenbrand Claudia M. 
Published: January 2017

PurposeHepatic iron content (HIC) quantification via transverse relaxation rate (R2*)‐MRI using multi‐gradient echo (mGRE) imaging is compromised toward high HIC or at higher fields due to the rapid signal decay. Our study aims at presenting an optimized 2D ultrashort echo time (UTE) sequence for R2* quantification to overcome these limitations.MethodsTwo‐dimensional UTE imaging was realized via half‐pulse excitation and radial center‐out sampling. The sequence includes chemically selective saturation pulses to reduce streaking artifacts from subcutaneous fat, and spatial saturation (sSAT) bands to suppress out‐of‐slice signals. The sequence employs interleaved multi‐echo readout trains to achieve dense temporal sampling of rapid signal decays. Evaluation was done at 1.5 Tesla (T) and 3T in phantoms, and clinical applicability was demonstrated in five patients with biopsy‐confirmed massively high HIC levels (>25 mg Fe/g dry weight liver tissue).ResultsIn phantoms, the sSAT pulses were found to remove out‐of‐slice contamination, and R2* results were in excellent agreement to reference mGRE R2* results (slope of linear regression: 1.02/1.00 for 1.5/3T). UTE‐based R2* quantification in patients with massive iron overload proved successful at both field strengths and was consistent with biopsy HIC values.ConclusionThe UTE sequence provides a means to measure R2* in patients with massive iron overload, both at 1.5T and 3T. Magn Reson Med 78:1839–1851, 2017. © 2017 Wiley Periodicals, Inc.
Extremal eigenvalue intervals of symmetric tridiagonal interval matrices
Authors: Jian Yuan 
Published: January 2017

SummaryComputing the extremal eigenvalue bounds of interval matrices is non‐deterministic polynomial‐time (NP)‐hard. We investigate bounds on real eigenvalues of real symmetric tridiagonal interval matrices and prove that for a given real symmetric tridiagonal interval matrices, we can achieve its exact range of the smallest and largest eigenvalues just by computing extremal eigenvalues of four symmetric tridiagonal matrices.
Optimal control strategy–based AGC of electrical power systems: A comparative performance analysis
Authors: Arya Yogendra , Kumar Narendra 
Published: January 2017

SummaryThis study extensively addresses the application of optimal control approach to the automatic generation control (AGC) of electrical power systems. Proportional‐integral structured optimal controllers are designed using full‐state feedback control strategy employing performance index minimization criterion. Some traditional single/multiarea and restructured multiarea power system models from the literature are explored deliberately in the present study. The dynamic performance of optimal controllers is observed superior in comparison to integral/proportional‐integral controllers tuned using some recently published modern heuristic optimization techniques. It is observed that optimal controllers show better system results in terms of minimum value of settling time, peak overshoot/undershoot, various performance indices, and oscillations corresponding to change in area frequencies and tie‐line powers along with maximum value of minimum damping ratio in comparison to other controllers. The results are displayed in the form of tables for ease of comparison. Sensitivity analysis affirms the robustness of the optimal feedback controller gains to wide variations in some system parameters from their nominal values.