bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical simulation and wind tunnel experiment on aerodynamic characteristics of an electric aircraft
Authors: Wang Kaijing 
Published: October 2023

Abstract
Taking an electric aircraft with high aspect ratio as the object of research, the CFD numerical simulation based on Navier-Stokes calculation and Spalart-Allmaras onflow pattern is conducted to verify the aerodynamic design and evaluate the flight property and quality of aircraft. With the aim of verifying the reasonability of the CFD calculation, a wind tunnel experiment was conducted for evaluation. The results indicate that the simulation information coincide well with wind tunnel test data, indicating that the simulation method could provide a guidance for the aerodynamic design of electric aircrafts, especially those with high aspect ratio.
Research on microstructure and properties of 3D plasma spray welding repair layer of continuous casting segmented rollers
Authors: Li Yuxiang , Zhou Ying , Meng Zhengbing , Liu Xiao , Zhang Xin , Chen Yuanyu , Shen Jialong , Liao Jiachi 
Published: October 2023

Abstract
In this paper, the Fe-Cr-Ni-Si powder was used in a 3D plasma spray welding machine to perform spray welding repair tests on continuous casting segmented rollers for service life improvement. The phase composition, hardness distribution, abrasion resistance and thermal stability of the spray welding layer were analyzed. Results indicated that the spray welding layer produced by 160 A welding current was more uniform and was with finer organization. The main phase zone was a single γ-Fe and the fusion zone was metallurgically combined with the base metal in a planar grain manner. The hardness of the spray welding layer was the maximum when the welding current was 160 A. The abrasion resistance for each position of the spray welding layer was uniform. The γ-Fe phase zone decreased and the α-Fe phase zone increased with reduction of average hardness after the thermal stability test. In industrial tests, the optimum spray welding parameters were verified and the service life of the continuous casting segmented rollers with spray welding was 2 longer than rollers using surfacing welding process.
Analysing active power reserve strategies for photovoltaic systems under varying shading scenarios: a comparative study
Authors: Verma Pankaj , Katal Nitish 
Published: October 2023

Abstract
The installed capacity of grid-connected solar photovoltaic (PV) systems is increasing rapidly; therefore, in the near future, the total system inertia may possibly decrease. Reserving some active power in PV systems is crucial to manage the problem of low inertia. In this paper, we critically analyse and compare the performances of several active power reserve and frequency regulation techniques for PV systems. The discussed techniques do not use energy storage devices and are aimed at enabling the inertial capabilities of PV systems. These techniques are broadly classified according to the shading conditions and methodologies adopted for reserve generation. In this paper, we closely investigate different deloading techniques used in PV systems. In deloading, PV systems are operated at a voltage distant from the maximum power point. Further, we also address the effectiveness and suitability of the aforementioned techniques under different operating conditions. Through this review paper, we aim to provide a one-stop reference for PV researchers to select appropriately from the available reserve techniques for designing flexible DC–DC controls for PV systems.
Enhanced independent component analysis and fuzzy C-mean clustering based on novel bat algorithm for noisy image segmentation
Authors: Chetih Nabil , Thelaidjia Tawfik , Boudani Fatma Zohra 
Published: October 2023

Abstract
Fuzzy c-means clustering is widely recognized as one of the most effective methods for image segmentation and achieving accurate classification. However, this method has two significant drawbacks: its sensitivity to noise and its convergence to local minimum clusters’ centroids. In this paper, we proposed a novel model called EIFCMNB, which incorporates enhanced independent component analysis (EICA), fuzzy c-means clustering (FCMC) and novel bat algorithm (NBA) for noise image segmentation. The suggested model consists of two main phases: image denoising and extraction of the regions of interest (ROIs). In the first phase, the enhanced independent component analysis (EICA) algorithm is used for recovering a good quality image, from a noisy image of poor quality. Several noisy images, with noise variances ranging from 5 to 20, were filtered. The resulting images were then evaluated based on several criteria viz: Peak Signal to Noise Ratio (PSNR), Relative Norm Error (RE), Normalized Cross-Correlation (NCC), and Structural Similarity index measure (SSIM). In the second phase, the fuzzy c-means clustering based on a novel bat algorithm is adopted to calculate optimal clusters’ centroids and extract the ROIs. By incorporating the new bat algorithm, we aim to overcome the problem of converging to local minimums and achieve improved segmentation accuracy. Promising experimental results have been obtained by applying the proposed model to MRI brain images and x-ray welding images. Two criteria viz: VPE end VPC have been employed to evaluate the suggested approach. The experiments clearly demonstrate that our suggested model effectively addresses the sensitivity to noise problem and provides optimal clusters’ centroids. Moreover, it outperforms several FCMC-based algorithms, exhibiting superior performance in terms of image segmentation and classification.
Governing equation discovery based on causal graph for nonlinear dynamic systems
Authors: Jia Dongni , Zhou Xiaofeng , Li Shuai , Liu Shurui , Shi Haibo 
Published: October 2023

Abstract
The governing equations of nonlinear dynamic systems is of great significance for understanding the internal physical characteristics. In order to learn the governing equations of nonlinear systems from noisy observed data, we propose a novel method named governing equation discovery based on causal graph that combines spatio-temporal graph convolution network with governing equation modeling. The essence of our method is to first devise the causal graph encoding based on transfer entropy to obtain the adjacency matrix with causal significance between variables. Then, the spatio-temporal graph convolutional network is used to obtain approximate solutions for the system variables. On this basis, automatic differentiation is applied to obtain basic derivatives and form a dictionary of candidate algebraic terms. Finally, sparse regression is used to obtain the coefficient matrix and determine the explicit formulation of the governing equations. We also design a novel cross-combinatorial optimization strategy to learn the heterogeneous parameters that include neural network parameters and control equation coefficients. We conduct extensive experiments on seven datasets from different physical fields. The experimental results demonstrate the proposed method can automatically discover the underlying governing equation of the systems, and has great robustness.
Invasive macroalgae in native seagrass beds: vectors of spread and impacts
Authors: Firth Louise B , Foggo Andy , Watts Thomas , Knights Antony M , deAmicis Stacey 
Published: October 2023

Abstract

Background and Aims
Worldwide, invasive species are spreading through marine systems at an unprecedented rate with both positive and negative consequences for ecosystems and the biological functioning of organisms. Human activities from shipping to habitat damage and modification are known vectors of spread, although biological interactions including epibiosis are increasingly recognized as potentially important to introduction into susceptible habitats.

Methods
We assessed a novel mechanism of spread – limpets as transporters of an invasive alga, Sargassum muticum, into beds of the seagrass Zostera marina – and the physiological impact of its invasion. The association of S. muticum with three limpet species and other habitats was assessed using intertidal surveys on rocky shores and snorkelling at two seagrass sites in the UK. A 4-year field study tested the effect of S. muticum on Z. marina shoot density, dry weight and phenolic compounds (caffeic and tannic acid) content, and a laboratory experiment tested the impact of S. muticum on nutrient partitioning (C/H/N/P/Si), photosynthetic efficiency (Fv/Fm) and growth of Z. marina.

Results
On rocky shores 15 % of S. muticum occurrences were attached to the shells of live limpets. In seagrass beds 5 % of S. muticum occurrences were attached to the shells of dead limpets. The remainder were attached to rock, to cobblestones, to the seagrass matrix or embedded within the sand. Z. marina density and phenolics content was lower when S. muticum co-occurred with it. Over 3 years, photosynthetic responses of Z. marina to S. muticum were idiosyncratic, and S. muticum had no effect on nutrient partitioning in Z. marina.

Conclusions
Our results show limpets support S. muticum as an epibiont and may act as a previously unreported transport mechanism introducing invaders into sensitive habitats. S. muticum reduced production of phenolics in Z. marina, which may weaken its defensive capabilities and facilitate proliferation of S. muticum. The effect of S. muticum on Z. marina photosynthesis requires further work but having no effect on the capacity of Z. marina to sequester nutrients suggests a degree of resilience to this invader.
Noradrenergic alterations in Parkinson’s disease: a combined 11C-yohimbine PET/neuromelanin MRI study
Authors: Laurencin Chloé , Lancelot Sophie , Brosse Sarah , Mérida Inés , Redouté Jérôme , Greusard Elise , Lamberet Ludovic , Liotier Véronique , Le Bars Didier , Costes Nicolas , Thobois Stéphane , Boulinguez Philippe , Ballanger Bénédicte 
Published: October 2023

Abstract
Degeneration of the noradrenergic system is now considered a pathological hallmark of Parkinson’s disease, but little is known about its consequences in terms of parkinsonian manifestations. Here, we evaluated two aspects of the noradrenergic system using multimodal in vivo imaging in patients with Parkinson’s disease and healthy controls: the pigmented cell bodies of the locus coeruleus with neuromelanin sensitive MRI; and the density of α2-adrenergic receptors (ARs) with PET using 11C-yohimbine.
Thirty patients with Parkinson’s disease and 30 age- and sex-matched healthy control subjects were included. The characteristics of the patients’ symptoms were assessed using the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS). Patients showed reduced neuromelanin signal intensity in the locus coeruleus compared with controls and diminished 11C-yohimbine binding in widespread cortical regions, including the motor cortex, as well as in the insula, thalamus and putamen. Clinically, locus coeruleus neuronal loss was correlated with motor (bradykinesia, motor fluctuations, tremor) and non-motor (fatigue, apathy, constipation) symptoms. A reduction of α2-AR availability in the thalamus was associated with tremor, while a reduction in the putamen, the insula and the superior temporal gyrus was associated with anxiety.
These results highlight a multifaceted alteration of the noradrenergic system in Parkinson’s disease since locus coeruleus and α2-AR degeneration were found to be partly uncoupled. These findings raise important issues about noradrenergic dysfunction that may encourage the search for new drugs targeting this system, including α2-ARs, for the treatment of Parkinson’s disease.
Unravelling the genomic features, phylogeny and genetic basis of tooth ontogenesis in Characiformes through analysis of four genomes
Authors: Yang Xianwei , Song Yue , Zhang Rui , Yu Mengjun , Guo Xinyu , Guo Haobing , Du Xiao , Sun Shuai , Li Chunhua , Mao Xuebin , Fan Guangyi , Liu Xin 
Published: October 2023

Abstract
Characiformes is a diverse and evolutionarily significant order of freshwater fish encompassing over 2,300 species. Despite its diversity, our understanding of Characiformes’ evolutionary relationships and adaptive mechanisms is limited due to insufficient genome sequences. In this study, we sequenced and assembled the genomes of four Characiformes species, three of which were chromosome-level assemblies. Our analyses revealed dynamic changes in gene family evolution, repeat sequences and variations in chromosomal collinearity within these genomes. With the assembled genomes, we were not only able to elucidate the evolutionary relationship of the four main orders in Otophysi but also indicated Characiformes as the paraphyletic group. Comparative genomic analysis with other available fish genomes shed light on the evolution of genes related to tooth development in Characiformes. Notably, variations in the copy number of secretory calcium-binding phosphoproteins (SCPP) genes were observed among different orders of Otophysi, indicating their potential contribution to the diversity of tooth types. Our study offers invaluable genome sequences and novel insights into Characiformes’ evolution, paving the way for further genomic and evolutionary research in fish.
A preoperative computed tomography radiomics model to predict disease-free survival in patients with pancreatic neuroendocrine tumors
Authors: Homps Margaux , Soyer Philippe , Coriat Romain , Dermine Solène , Pellat Anna , Fuks David , Marchese Ugo , terris Benoit , Groussin Lionel , Dohan Anthony , Barat Maxime 
Published: October 2023

Abstract

Importance
Imaging has demonstrated capabilities in the diagnosis of pancreatic neuroendocrine tumors (pNETs), but its utility for prognostic prediction has not been elucidated yet.

Objective
The aim of this study was to build a radiomics model using preoperative computed tomography (CT) data that may help predict recurrence-free survival (RFS) or OS in patients with pNET.

Design
We performed a retrospective observational study in a cohort of French patients with pNETs.

Participants
Patients with surgically resected pNET and available CT examinations were included.

Interventions
Radiomics features of preoperative CT data were extracted using 3D-Slicer® software with manual segmentation. Discriminant features were selected with penalized regression using least absolute shrinkage and selection operator method with training on the tumor Ki67 rate (≤2 or &gt;2). Selected features were used to build a radiomics index ranging from 0 to 1.

Outcome and measure
A receiving operator curve was built to select an optimal cutoff value of the radiomics index to predict patient RFS and OS. Recurrence-free survival and OS were assessed using Kaplan–Meier analysis.

Results
Thirty-seven patients (median age, 61 years; 20 men) with 37 pNETs (grade 1, 21/37 [57%]; grade 2, 12/37 [32%]; grade 3, 4/37 [11%]) were included. Patients with a radiomics index &gt;0.4 had a shorter median RFS (36 months; range: 1-133) than those with a radiomics index ≤0.4 (84 months; range: 9-148; P = .013). No associations were found between the radiomics index and OS (P = .86).
Dynamic changes of left atrial substrate over time following pulmonary vein isolation: the Progress-AF study
Authors: Marcon Lorenzo , Bergonti Marco , Spera Francesco , Saenen Johan , Huybrechts Wim , Miljoen Hielko , Van Leuven Olivier , Vandaele Lien , Wittock Anouk , Heidbuchel Hein , Sarkozy Andrea 
Published: October 2023

Abstract

Aims
Little is known about dynamic changes of the left atrial (LA) substrate over time in patients with atrial fibrillation (AF). This study aims to evaluate substrate changes following pulmonary vein isolation (PVI).

Methods and results
In our prospective observational study, consecutive patients undergoing first PVI-only and redo ablation were included. High-density maps of the two procedures were compared. Progression or regression was diagnosed if a significant concordant decrease or increase in bipolar voltages in ≥2 segments was observed, respectively. In 28 patients (61.2 ± 9.5 years, 39% female, 53.5% persistent AF), 111.013 voltage points from 56 high-density LA maps (1.982 points/patient) were analysed. Comparing the high-density maps of the first and second procedures, in the progression group (17 patients, 61%), there was a decrease in global (−35%, P &lt; 0.001) and all regional voltages. In the regression group (11 patients, 39%), there was an increase in global (+43%, P &lt; 0.001) and regional voltages. Comparing the progression with the regression group, the area of low-voltage zone (LVZ) increased (+3.5 vs. −4.5 cm2, P &lt; 0.001) and LA activation time prolonged (+8.0 vs. −9.1 ms, P = 0.005). Baseline clinical parameters did not predict progression or regression. In patients with substrate progression, pulmonary veins (PVs) were more frequently isolated (P = 0.02) and the AF pattern at recurrence was more frequently persistent (P = 0.005).

Conclusion
Our study describes bidirectional dynamic properties of the LA substrate with concordant either progressive or regressive changes. Regression occurs with reduced AF burden after the first procedure, while progression is associated with persistent AF recurrence despite durable PV isolation. The dynamic nature of LA substrate poses questions about LVZ-based ablation strategies.
Orthologs of the Caenorhabditis elegans heterochronic genes have divergent functions in Caenorhabditis briggsae
Authors: Ivanova Maria , Moss Eric G 
Published: October 2023

Abstract
The heterochronic genes of Caenorhabditis elegans comprise the best-studied pathway controlling the timing of tissue and organ formation in an animal. To begin to understand the evolution of this pathway and the significance of the relationships among its components, we characterized 11 Caenorhabditis briggsae orthologs of C. elegans heterochronic genes. Using CRISPR/Cas9, we made a variety of alleles and found that several mutant phenotypes differ in significant ways from those of C. elegans. Although most mutant orthologs displayed defects in developmental timing, their phenotypes could differ in which stages were affected, the penetrance and expressivity of the phenotypes, or by having additional pleiotropies that were not obviously connected to developmental timing. However, when examining pairwise epistasis and synergistic relationships, we found those paralleled the known relationships between their C. elegans orthologs, suggesting that the arrangements of these genes in functional modules are conserved, but the modules’ relationships to each other and/or to their targets has drifted since the time of the species’ last common ancestor. Furthermore, our investigation has revealed a relationship between this pathway to other aspects of the animal's growth and development, including gonad development, which is relevant to both species.
Construction and analysis of the chromosome-level haplotype-resolved genomes of two Crassostrea oyster congeners: Crassostrea angulata and Crassostrea gigas
Authors: Qi Haigang , Cong Rihao , Wang Yanjun , Li Li , Zhang Guofan 
Published: October 2023

Abstract

Background
The Portuguese oyster Crassostrea angulata and the Pacific oyster C. gigas are two major Crassostrea species that are naturally distributed along the Northwest Pacific coast and possess great ecological and economic value. Here, we report the construction and comparative analysis of the chromosome-level haplotype-resolved genomes of the two oyster congeners.

Findings
Based on a trio-binning strategy, the PacBio high-fidelity and Illumina Hi-C reads of the offspring of the hybrid cross C. angulata (♂) × C. gigas (♀) were partitioned and independently assembled to construct two chromosome-level fully phased genomes. The assembly size (contig N50 size, BUSCO completeness) of the two genomes were 582.4 M (12.8 M, 99.1%) and 606.4 M (5.46 M, 98.9%) for C. angulata and C. gigas, respectively, ranking at the top of mollusk genomes with high contiguity and integrity. The general features of the two genomes were highly similar, and 15,475 highly conserved ortholog gene pairs shared identical gene structures and similar genomic locations. Highly similar sequences can be primarily identified in the coding regions, whereas most noncoding regions and introns of genes in the same ortholog group contain substantial small genomic and/or structural variations. Based on population resequencing analysis, a total of 2,756 species-specific single-nucleotide polymorphisms and 1,088 genes possibly under selection were identified.

Conclusions
This is the first report of trio-binned fully phased chromosome-level genomes in marine invertebrates. The study provides fundamental resources for the research on mollusk genetics, comparative genomics, and molecular evolution.
Distributed model predictive control of vehicle platoons under switching communication topologies
Authors: Chen Liang , Zhan Jingyuan , Zhang Liguo 
Published: October 2023

Abstract
This paper studies the control problem for vehicle platoons under switching communication topologies, where the Predecessor-Following (PF)-failure topology is allowed. Firstly, we design a local optimization problem for each vehicle by using the state information of itself and its neighbouring vehicles, and then present Algorithm 1 based on Distributed Model Predictive Control (DMPC). By constructing a common Lyapunov function defined by the joint neighbourhood set, we derive sufficient conditions with respect to the weight matrices in the open-loop optimization problem and the switching topologies for ensuring the stability of the closed-loop system under Algorithm 1. Furthermore, we propose Algorithm 2 by introducing novel constraints into the local optimization problem for each vehicle, which utilize shrinking historical position errors to cope with PF-link failures, such that the string stability of the vehicle platoon is ensured. Finally, numerical examples are presented to demonstrate the effectiveness of the proposed DMPC algorithms for the vehicel platoon under switching communication topologies.
Artificial Intelligence and Infectious Disease Imaging
Authors: Chu Winston T , Reza Syed M S , Anibal James T , Landa Adam , Crozier Ian , Bağci Ulaş , Wood Bradford J , Solomon Jeffrey 
Published: October 2023

AbstractThe mass production of the graphics processing unit and the coronavirus disease 2019 (COVID-19) pandemic have provided the means and the motivation, respectively, for rapid developments in artificial intelligence (AI) and medical imaging techniques. This has led to new opportunities to improve patient care but also new challenges that must be overcome before these techniques are put into practice. In particular, early AI models reported high performances but failed to perform as well on new data. However, these mistakes motivated further innovation focused on developing models that were not only accurate but also stable and generalizable to new data. The recent developments in AI in response to the COVID-19 pandemic will reap future dividends by facilitating, expediting, and informing other medical AI applications and educating the broad academic audience on the topic. Furthermore, AI research on imaging animal models of infectious diseases offers a unique problem space that can fill in evidence gaps that exist in clinical infectious disease research. Here, we aim to provide a focused assessment of the AI techniques leveraged in the infectious disease imaging research space, highlight the unique challenges, and discuss burgeoning solutions.