bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparative study of convolutional neural network models for wind field downscaling
Authors: Höhlein Kevin , Kern Michael , Hewson Timothy , Westermann Rüdiger 
Published: December 2020

AbstractWe analyze the applicability of convolutional neural network (CNN) architectures for downscaling of short‐range forecasts of near‐surface winds on extended spatial domains. Short‐range wind forecasts (at the 100 m level) from European Centre for Medium Range Weather Forecasts ERA5 reanalysis initial conditions at 31 km horizontal resolution are downscaled to mimic high resolution (HRES) (deterministic) short‐range forecasts at 9 km resolution. We evaluate the downscaling quality of four exemplary CNN architectures and compare these against a multilinear regression model. We conduct a qualitative and quantitative comparison of model predictions and examine whether the predictive skill of CNNs can be enhanced by incorporating additional atmospheric variables, such as geopotential height and forecast surface roughness, or static high‐resolution fields, like land–sea mask and topography. We further propose DeepRU, a novel U‐Net‐based CNN architecture, which is able to infer situation‐dependent wind structures that cannot be reconstructed by other models. Inferring a target 9 km resolution wind field from the low‐resolution input fields over the Alpine area takes less than 10 ms on our graphics processing unit target architecture, which compares favorably to an overhead in simulation time of minutes or hours between low‐ and high‐resolution forecast simulations.
A narrow band and high selectivity half‐mode substrate integrated waveguide bandpass filter with interdigital slots
Authors: Pelluri Sambaiah , M.V. Kartikeyan 
Published: December 2020

AbstractA novel in‐line half‐mode substrate integrated waveguide (HMSIW) bandpass filter with interdigital slots has been proposed in this letter. Here, the interdigital slot shows attenuation resonance characteristics and generates a finite frequency transmission zero (TZ). The proposed filter generates two TZs without additional coupling or extra space and exhibits wide stopband characteristics. To validate this method, the in‐line two‐pole quasi‐elliptic bandpass filter is synthesized and fabricated on RT/Duroid 5880 substrate using printed circuit board technology. The experimental results show that center frequency, 3‐dB fractional bandwidth, insertion loss, and return loss are 3.6 GHz, 6.0%, 1.9 and 18 dB, respectively, and are very much similar to the simulated S‐parameters.
Free‐water DTI estimates from single b‐value data might seem plausible but must be interpreted with care
Authors: Golub Marc , Neto Henriques Rafael , Gouveia Nunes Rita 
Published: December 2020

PurposeFree‐water elimination DTI (FWE‐DTI) has been used widely to distinguish increases of free‐water partial‐volume effects from tissue’s diffusion in healthy aging and degenerative diseases. Because the FWE‐DTI fitting is only well‐posed for multishell acquisitions, a regularized gradient descent (RGD) method was proposed to enable application to single‐shell data, more common in the clinic. However, the validity of the RGD method has been poorly assessed. This study aims to quantify the specificity of FWE‐DTI procedures on single‐shell and multishell data.MethodsDifferent FWE‐DTI fitting procedures were tested on an open‐source in vivo diffusion data set and single‐shell and multishell synthetic signals, including the RGD and standard nonlinear least‐squares methods. Single‐voxel simulations were carried out to compare initialization approaches. A multivoxel phantom simulation was performed to evaluate the effect of spatial regularization when comparing between methods. To test the algorithms’ specificity, phantoms with two different types of lesions were simulated: with altered mean diffusivity or with modified free water.ResultsPlausible parameter maps were obtained with RGD from single‐shell in vivo data. The plausibility of these maps was shown to be determined by the initialization. Tests with simulated lesions inserted into the in vivo data revealed that the RGD approach cannot distinguish free water from tissue mean‐diffusivity alterations, contrarily to the nonlinear least‐squares algorithm.ConclusionThe RGD FWE‐DTI method has limited specificity; thus, its results from single‐shell data should be carefully interpreted. When possible, multishell acquisitions and the nonlinear least‐squares approach should be preferred instead.
A fast navigator (fastNAV) for prospective respiratory motion correction in first‐pass myocardial perfusion imaging
Authors: Mooiweer Ronald , Neji Radhouene , McElroy Sarah , Nazir Muhummad Sohaib , Razavi Reza , Chiribiri Amedeo , Roujol Sébastien 
Published: December 2020

PurposeTo develop and evaluate a fast respiratory navigator (fastNAV) for cardiac MR perfusion imaging with subject‐specific prospective slice tracking.MethodsA fastNAV was developed for dynamic contrast‐enhanced cardiac MR perfusion imaging by combining spatially nonselective saturation with slice‐selective tip‐up and slice‐selective excitation pulses. The excitation slice was angulated from the tip‐up slice in the transverse plane to overlap only in the right hemidiaphragm for suppression of signal outside the right hemidiaphragm. A calibration scan was developed to enable the estimation of subject‐specific tracking factors. Perfusion imaging using subject‐specific fastNAV‐based slice tracking was then compared to a conventional sequence (ie, without slice tracking) in 10 patients under free‐breathing conditions. Respiratory motion in perfusion images was quantitatively assessed by measuring the average overlap of the left ventricle across images (avDice, 0:no overlap/1:perfect overlap) and the average displacement of the center of mass of the left ventricle (avCoM). Image quality was subjectively assessed using a 4‐point scoring system (1: poor, 4: excellent).ResultsThe fastNAV calibration was successfully performed in all subjects (average tracking factor of 0.46 ± 0.13, R = 0.94 ± 0.03). Prospective motion correction using fastNAV led to higher avDice (0.94 ± 0.02 vs. 0.90 ± 0.03, P < .001) and reduced avCoM (4.03 ± 0.84 vs. 5.22 ± 1.22, P < .001). There were no statistically significant differences between the 2 sequences in terms of image quality (both sequences: median = 3 and interquartile range = 3‐4, P = 1).ConclusionfastNAV enables fast and robust right hemidiaphragm motion tracking in a perfusion sequence. In combination with subject‐specific slice tracking, fastNAV reduces the effect of respiratory motion during free‐breathing cardiac MR perfusion imaging.
Cardiac real‐time MRI using a pre‐emphasized spiral acquisition based on the gradient system transfer function
Authors: Eirich Philipp , Wech Tobias , Heidenreich Julius F. , Stich Manuel , Petri Nils , Nordbeck Peter , Bley Thorsten A. , Köstler Herbert 
Published: December 2020

PurposeSegmented Cartesian acquisition in breath hold represents the current gold standard for cardiac functional MRI. However, it is also associated with long imaging times and severe restrictions in arrhythmic or dyspneic patients. Therefore, we introduce a real‐time imaging technique based on a spoiled gradient‐echo sequence with undersampled spiral k‐space trajectories corrected by a gradient pre‐emphasis.MethodsA fully automatic gradient waveform pre‐emphasis based on the gradient system transfer function was implemented to compensate for gradient inaccuracies, to optimize fast double‐oblique spiral MRI. The framework was tested in a phantom study and subsequently transferred to compressed sensing–accelerated cardiac functional MRI in real time. Spiral acquisitions during breath hold and free breathing were compared with this reference method for healthy subjects (N = 7) as well as patients (N = 2) diagnosed with heart failure and arrhythmia. Left‐ventricular volumes and ejection fractions were determined and analyzed using a Wilcoxon signed‐rank test.ResultsThe pre‐emphasis successfully reduced typical artifacts caused by k‐space misregistrations. Dynamic cardiac imaging was possible in real time (temporal resolution < 50 ms) with high spatial resolution (1.34 × 1.34 mm2), resulting in a total scan time of less than 50 seconds for whole heart coverage. Comparable image quality, as well as similar left‐ventricular volumes and ejection fractions, were observed for the accelerated and the reference method.ConclusionThe proposed technique enables high‐resolution real‐time cardiac MRI with no need for breath holds and electrocardiogram gating, shortening the duration of an entire functional cardiac exam to less than 1 minute.
Using MRI to quantify skeletal muscle pathology in Duchenne muscular dystrophy: A systematic mapping review
Authors: Alic Lejla , Griffin John F. , Eresen Aydin , Kornegay Joe N. , Ji Jim X. 
Published: December 2020

AbstractThere is a great demand for accurate non‐invasive measures to better define the natural history of disease progression or treatment outcome in Duchenne muscular dystrophy (DMD) and to facilitate the inclusion of a large range of participants in DMD clinical trials. This review aims to investigate which MRI sequences and analysis methods have been used and to identify future needs. Medline, Embase, Scopus, Web of Science, Inspec, and Compendex databases were searched up to 2 November 2019, using keywords “magnetic resonance imaging” and “Duchenne muscular dystrophy.” The review showed the trend of using T1w and T2w MRI images for semi‐qualitative inspection of structural alterations of DMD muscle using a diversity of grading scales, with increasing use of T2map, Dixon, and MR spectroscopy (MRS). High‐field (>3T) MRI dominated the studies with animal models. The quantitative MRI techniques have allowed a more precise estimation of local or generalized disease severity. Longitudinal studies assessing the effect of an intervention have also become more prominent, in both clinical and animal model subjects. Quality assessment of the included longitudinal studies was performed using the Newcastle‐Ottawa Quality Assessment Scale adapted to comprise bias in selection, comparability, exposure, and outcome. Additional large clinical trials are needed to consolidate research using MRI as a biomarker in DMD and to validate findings against established gold standards. This future work should use a multiparametric and quantitative MRI acquisition protocol, assess the repeatability of measurements, and correlate findings to histologic parameters.
The supplement role of iron oxide and zirconium oxide nanoparticles as an advanced composite compound for enhancing the efficiency of thin‐film nanocomposite membranes
Authors: Karimi Rezvan , Homayoonfal Maryam 
Published: December 2020

AbstractIn this research, to enhance the efficiency of polyacrylonitrile, iron oxide (Fe3O4) nanoparticles were added to membrane matrix and M(0,1) (PA/FePAN) membrane was fabricated. To boost the effectiveness, the iron oxide/zirconium oxide composite nanoparticles (Zr©Fe) were added to the superficial polyamide layer to synthesize M(1,0) (Zr©FePA/PAN) membrane. In order to investigate the supplement role of Fe3O4 and Zr©Fe nanoparticles, both nanoparticles were added to PAN substrate and PA superficial layer, respectively, to fabricate M(1,1) (Zr©FePA/FePAN) membrane. The performance of nanocomposite membranes was compared with that of M(0,0) (PA/PAN) raw membrane. The results indicated that the contact angle of M(0,0), M(0,1), M(1,0), and M(1,1) membranes was 38, 32, 28, and 21, respectively. Presence of nanoparticles enhanced the membrane porosity, such that the porosity of M(0,0), M(1,0), M(0,1), and M(1,1) membranes was 24%, 27%, 30%, and 33%, respectively. MWCO for M(0,0), M(0,1), M(1,0), and M(1,1) membranes was 610, 595, 380, and 330 Dalton, respectively. Presence of nanoparticles reduced fouling from 22% for M(0,0) membrane to zero for M(1,1) membrane. Presence of Fe3O4 nanoparticles and Zr©Fe composite nanoparticles concurrently in both membrane layers eventually caused M(1,1) to have around 23% greater flux and 68% higher efficiency for cephalexin rejection compared to M(0,0).
Review on the performances, foaming and injection molding simulation of natural fiber composites
Authors: Zhan Jianghu , Li Jiao , Wang Guilong , Guan Yanjin , Zhao Guoqun , Lin Jun , Naceur Hakim , Coutellier Daniel 
Published: December 2020

AbstractRecently, natural fiber becomes an alternative to the synthetic fiber for the composites used in aerospace, automotive, sports, packaging and so on, due to its inherent characteristics like biodegradablity, renewablity, high‐specific strength and specific modulus. However, there are still many challenges in the fabrication of the natural fiber composites, including the poor compatibility between the nonpolar matrix and the polar natural fiber, relatively high‐moisture absorption and low‐thermal resistance of natural fibers, etc. Moreover, when manufacturing this type composite, the processing conditions, fiber loading and inherent properties of fiber not only affect the mechanical properties, but also cause products defects, such as warpage, volume shrinkage and weld lines, which needs a rapid numerical design for the mold and manufacturing parameters. Therefore, the properties of natural fiber composites have been widely investigated to satisfy the increasing demand in different applications. This paper intends to review the mechanical properties, flammability, durability, foaming behaviors and numerical simulation of injection molding process of natural fiber composites.
Differentiation of the binding of two ligands to a tetrameric protein with a single symmetric active site by 19F NMR
Authors: Fuente‐Gómez Gabriel J. , Kellum Creighton L. , Miranda Alexis C. , Duff Michael R. , Howell Elizabeth E. 
Published: December 2020

AbstractR67 dihydrofolate reductase (R67 DHFR) is a plasmid‐encoded enzyme that confers resistance to the antibacterial drug trimethoprim. R67 DHFR is a tetramer with a single active site that is unusual as both cofactor and substrate are recognized by symmetry‐related residues. Such promiscuity has limited our previous efforts to differentiate ligand binding by NMR. To address this problem, we incorporated fluorine at positions 4, 5, 6, or 7 of the indole rings of tryptophans 38 and 45 and characterized the spectra to determine which probe was optimal for studying ligand binding. Two resonances were observed for all apo proteins. Unexpectedly, the W45 resonance appeared broad, and truncation of the disordered N‐termini resulted in the appearance of one sharp W45 resonance. These results are consistent with interaction of the N‐terminus with W45. Binding of the cofactor broadened W38 for all fluorine probes, whereas substrate, dihydrofolate, binding resulted in the appearance of three new resonances for 4‐ and 5‐fluoroindole labeled protein and severe line broadening for 6‐ and 7‐fluoroindole R67 DHFR. W45 became slightly broader upon ligand binding. With only two peaks in the 19F NMR spectra, our data were able to differentiate cofactor and substrate binding to the single, symmetric active site of R67 DHFR and yield binding affinities.
RNAi‐based gene silencing in Phenacoccus solenopsis and its validation by in planta expression of a double‐stranded RNA
Authors: Arya Surjeet Kumar , Singh Sanchita , Upadhyay Santosh Kumar , Tiwari Vipin , Saxena Gauri , Verma Praveen C 
Published: December 2020

AbstractBACKGROUNDCotton is a cash crop majorly affected by many hemipteran pests, among them the cotton mealybug, Phenacoccus solenopsis. Cotton mealybug attack has a devastating effect on cotton production and causes huge yield losses.RESULTSIn this study, 25 potential RNA interference (RNAi) target genes were selected from the iBeetle database and a transcriptome data set for P. solenopsis. To assess the effectiveness of the selected target genes, three methods were utilized to deliver double‐stranded (ds)RNA (ingestion, artificial diet bioassay and transient gene silencing). dsRNA molecules at different concentrations were fed to insects and insect mortality was recorded for each target gene. Based on the mortality data, three genes, Krüppel homologue‐1, ADP‐ATP/Translocase and IDGF‐1, were selected for further gene expression studies using a reduced concentration of dsRNA (5 μg/ml). Of the three genes, Krüppel homologue‐1 showed significantly downregulated expression (by 70.81% and 84.33%) at two different time points (8 and 14 days). An RNAi silencing construct was designed for Krüppel homologue‐1 under control of the double enhancer CamV35S promoter in the plant binary vector. Significant downregulation of gene expression, by 66.69% and 81.80%, was found for Krüppel homologue‐1 using transient gene silencing at the same time intervals.CONCLUSIONThis work provides the first evidence for targeting the Krüppel homologue‐1 gene in a hemipteran pest, P. solenopsis, using RNAi technology through oral delivery and in planta‐based transient gene silencing methods. © 2020 Society of Chemical Industry
Long‐term effect of fumigation and a sorghum cover crop on broadleaf and grass weeds in plastic‐mulched tomato
Authors: Yu Jialin , Sharpe Shaun M , Boyd Nathan S 
Published: December 2020

AbstractBACKGROUNDBroadleaf and grass weeds can adversely affect growth and productivity of plastic‐mulched tomato (Solanum lycopersicum L.). Two, four‐year research trials were conducted in Florida to evaluate the effect of repeated fumigation and chemical fallow versus a sorghum [Sorghum bicolor S. bicolor var. sudanense (Piper) Stapf.] cover crop on broadleaf and grass weeds in tomato plasticulture.RESULTS1,3‐Dichloropropene (1,3‐D) + chloropicrin (Pic), dimethyl disulfide (DMDS) + Pic, and DMDS + metam potassium effectively controlled broadleaf weeds in‐crop and reduced densities by 79–98% compared to the non‐fumigated control but provided inconsistent control of grass weeds. DMDS + metam potassium was generally the most effective fumigant. During the fallow period, a sorghum cover crop effectively reduced broadleaf weed density than the chemical fallow, while chemical fallow effectively reduced grass weed density than the cover crop. The fallow program did not affect in‐crop densities of broadleaf and grass weeds. In some measurements, the evaluated fumigants resulted in taller tomato plants and higher yield compared to the non‐fumigated control.CONCLUSIONWe conclude that the evaluated soil fumigants effectively control broadleaf and grass weeds. Planting a sorghum cover crop effectively suppresses broadleaf weeds but not grasses during the fallow period. However, this suppression does not result in reduced weed density in‐crop despite the fact that similar weed species were observed in both time periods. © 2020 Society of Chemical Industry
Factors affecting deer pressure on forest regeneration: The roles of forest roads, visibility and forage availability
Authors: Borowski Zbigniew , Bartoń Kamil , Gil Wojciech , Wójcicki Adam , Pawlak Bogdan 
Published: December 2020

AbstractBACKGROUNDDeer pressure on forest regeneration constitutes a serious problem in commercial forests in the northern hemisphere due to the increase in deer populations. However, other drivers, such as climate, landscape structure and the level of human activity, have a strong influence on deer pressure. The direct, density‐related impacts of ungulates on forest regeneration have been well studied, but there is limited empirical evidence related to the indirect factors mentioned above. We conducted a field experiment in three forest divisions in Poland to evaluate the role of a common element of human infrastructure, i.e. small, unpaved forestry roads. Additionally, we assessed the modifying effect of visibility driven by vegetation cover and forage availability.RESULTSThe proximity of unpaved roads affected deer habitat use and foraging behaviour, and limited browsing pressure on regenerating forests. Low visibility and higher winter forage availability increased the probability of tree browsing. We observed different responses to roads in two deer species: red deer avoided roads, while roe deer browsed in the vicinity of roads.CONCLUSIONSA typical forest network of unpaved roads creates a landscape of fear for red and roe deer, and limits browsing pressure on regenerating forests due to the changes in deer habitat use, activity patterns and foraging behaviour. Knowledge of the factors influencing browsing pressure can help to spatially optimise the application of protective measures for tree seedlings.
Variational Quantum Generators: Generative Adversarial Quantum Machine Learning for Continuous Distributions
Authors: Romero Jonathan , Aspuru‐Guzik Alán 
Published: December 2020

AbstractA hybrid quantum–classical approach to model continuous classical probability distributions using a variational quantum circuit is proposed. The architecture of this quantum generator consists of a quantum circuit that encodes a classical random variable into a quantum state and a parameterized quantum circuit trained to mimic the target distribution. The model allows for easy interfacing with a classical function, such as a neural network, and is trained using an adversarial learning approach. It is shown that the quantum generator is able to learn using either a classical neural network or a variational quantum circuit as the discriminator model. This implementation takes advantage of automatic differentiation tools to perform the optimization of the variational circuits employed. The framework presented here for the design and implementation of the variational quantum generators can serve as a blueprint for designing hybrid quantum–classical models for other machine learning tasks.
Enhanced Spin Hall Effect in S‐Implanted Pt
Authors: Shashank Utkarsh , Medwal Rohit , Shibata Taiga , Nongjai Razia , Vas Joseph Vimal , Duchamp Martial , Asokan Kandasami , Rawat Rajdeep Singh , Asada Hironori , Gupta Surbhi , Fukuma Yasuhiro 
Published: December 2020

AbstractHigh efficiency of charge–spin interconversion in spin Hall materials is a prime necessity to apprehend intriguing functionalities of spin–orbit torque for magnetization switching, auto‐oscillations, and domain wall motion in energy‐efficient and high‐speed spintronic devices. To this end, innovations in fabricating advanced materials that possess not only large charge–spin conversion efficiency but also viable electrical and spin Hall conductivity are of importance. Here, a new spin Hall material designed by implanting low energy 12 keV sulfur ions in heavy metal Pt, named as Pt(S), is reported that demonstrates eight times higher conversion efficiency as compared to pristine Pt. The figure of merit, spin Hall angle (θSH), up to of 0.502 together with considerable electrical conductivity of 1.65 × 106 Ω–1 m–1 is achieved. The spin Hall conductivity increases with increasing , as , implying an intrinsic mechanism in a dirty metal conduction regime. A comparatively large of 8.32 × 105 () Ω–1 m–1 among the reported heavy‐metals‐based alloys can be useful for developing next‐generation spintronic devices using spin–orbit torque.
The Origin of Quantum Effects in Low‐Dimensional Thermoelectric Materials
Authors: Hung Nguyen T. , Saito Riichiro 
Published: December 2020

AbstractThermoelectric material, which directly converts waste heat to electricity, provides an ecofriendly power generator to reuse heat energy sources. New attempts have started for thermoelectricity of low‐dimensional materials since 1993 when the theory of confinement effect was presented by Hicks and Dresselhaus. Experimental works have been inspired by the theory of confinement to the use of low‐dimensional materials for improving thermoelectric efficiency for more than two decades. In this report, it is considered how recent theories and experiments have made progress on the quantum confinement effects. In particular, the reason is explained why the thermal de Broglie wavelength becomes a key parameter to enhance the power factor.