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Journal of Dynamics, Monitoring and Diagnostics 2023年第2期2卷 144-154页

作者： Maarten Meire Quinten Van Baelen Ted Ooijevaar Peter Karsmakers Department of Computer Science KU LeuvenADVISE-DTAIKleinhoefstraat 4 B-2440 GeelBelgium leuven.AI–ku leuven institute for AI 3000 LeuvenBelgium Flanders Make@ku leuven 3000 LeuvenBelgium Flanders Make vzw CoreLab MotionSLeuven 3001Belgium

Anomaly detection(AD)is an important task in a broad range of domains.A popular choice for AD are Deep Support Vector Data Description *** learning such models,normal data is mapped close to and anomalous data is mapped far from a center,in some latent space,enabling the construction of a sphere to separate both types of ***,it was observed:(i)that the center and radius of such sphere largely depend on the training data and model initialization which leads to difficulties when selecting a threshold,and(ii)that the center and radius of this sphere strongly impact the model AD performance on unseen *** this work,a more robust AD solution is proposed that(i)defines a sphere with a fixed radius and margin in some latent space and(ii)enforces the encoder,which maps the input to a latent space,to encode the normal data in a small sphere and the anomalous data outside a larger sphere,with the same *** results indicate that the proposed algorithm attains higher performance compared to alternatives,and that the difference in size of the two spheres has a minor impact on the performance.

关键词： anomaly detection autoencoders deep learning

De novo serine synthesis regulates chondrocyte proliferation during bone development and repair

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Bone Research 2022年第2期10卷 274-285页

作者： Steve Stegen Shauni Loopmans Ingrid Stockmans Karen Moermans Peter Carmeliet Geert Carmeliet Laboratory of Clinical and Experimental Endocrinology Department of Chronic Diseases and MetabolismKU Leuven3000 LeuvenBelgium Laboratory of Angiogenesis and Vascular Metabolism VIB Center for Cancer Biology3000 LeuvenBelgium Laboratory of Angiogenesis and Vascular Metabolism Department of Oncology and Leuven Cancer InstituteKU Leuven3000 LeuvenBelgium State Key Laboratory of Ophthalmology Zhongshan Ophthalmic CenterSun Yat-Sen UniversityGuangzhou 510080China

The majority of the mammalian skeleton is formed through endochondral ossification starting from a cartilaginous *** cells, or chondrocytes, survive, proliferate and synthesize extracellular matrix in an avascular environment, but the metabolic requirements for these anabolic processes are not fully understood. Here, using metabolomics analysis and genetic in vivo models, we show that maintaining intracellular serine homeostasis is essential for chondrocyte function. De novo serine synthesis through phosphoglycerate dehydrogenase(PHGDH)-mediated glucose metabolism generates nucleotides that are necessary for chondrocyte proliferation and long bone growth. On the other hand, dietary serine is less crucial during endochondral bone formation, as serine-starved chondrocytes compensate by inducing PHGDH-mediated serine ***, this metabolic flexibility requires ATF4, a transcriptional regulator of amino acid metabolism and stress *** demonstrate that both serine deprivation and PHGDH inactivation enhance ATF4 signaling to stimulate de novo serine synthesis and serine uptake, respectively, and thereby prevent intracellular serine depletion and chondrocyte dysfunction. A similar metabolic adaptability between serine uptake and de novo synthesis is observed in the cartilage callus during fracture ***, the results of this study reveal a critical role for PHGDH-dependent serine synthesis in maintaining intracellular serine levels under physiological and serine-limited conditions, as adequate serine levels are necessary to support chondrocyte proliferation during endochondral ossification.

关键词： synthesis starting thereby

Heterogeneous tunable Ⅲ-Ⅴ-on-silicon-nitride mode-locked laser emitting wide optical spectra

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Photonics Research 2024年第3期12卷 I0021-I0027页

作者： MAXIMILIEN BILLET STIJN CUYVERS STIJN POELMAN ARTUR HERMANS SANDEEP SEEMA SASEENDRA TASUku NAKAMURA SHINYA OKAMOTO YASUHISA INADA KAZUYA HISADA TAku HIRASAWA JOAN RAMIREZ DELPHINE NÉEL NICOLAS VAISSIÈRE JEAN DECOBERT PHILIPPE SOUSSAN XAVIER ROTTENBERG GUNTHER ROELKENS JONØ.KJELLMAN BART kuYKEN Photonics Research Group Department of Information TechnologyGhent University-imec9052 GhentBelgium imec 3001 LeuvenBelgium Technology Division Panasonic Holdings CorporationMoriguchi-CityOsakaJapan Ⅲ-Ⅴ Lab F91767 PalaiseauFrance

We demonstrate a Ⅲ-Ⅴ-on-silicon-nitride mode-locked laser through the heterogeneous integration of a semiconductor optical amplifier on a passive silicon-nitride cavity using the technique of micro-transfer printing. In the initial phase of our study, we focus on optimizing the lasing wavelength to be centered at 1550 nm. This optimization is achieved by conducting experiments with 27 mode-locked lasers, each incorporating optical amplifiers featuring distinct multiple-quantum-well photoluminescence values. Subsequently we present a comprehensive study investigating the behavior of the mode-locking regime when the electrical driving parameters are varied. Specifically, we explore the impact of the gain voltage and saturable absorber current on the locking stability of a tunable mode-locked laser. By manipulating these parameters, we demonstrate the precise control of the optical spectrum across a wide range of wavelengths spanning from 1530 to 1580 nm. Furthermore, we implement an optimization approach based on a Monte Carlo analysis aimed at enhancing the mode overlap within the gain region. This adjustment enables the achievement of a laser emitting a 23-nm-wide spectrum while maintaining a defined 10 dB bandwidth for a pulse repetition rate of 3 GHz.

关键词： tunable amplifier mode

Upward surface movement above deep coal mines after closure and flooding of underground workings

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International Journal of Mining Science and Technology 2018年第1期28卷 53-59页

作者： André Vervoort Pierre-Yves Declercq Department of Civil Engineering KU Leuven Geological Survey of Belgium Royal Belgian Institute of Natural Sciences

After the mass closures of entire coal mine districts in Europe at the end of the last century, a new phenomenon of surface movement was observed—an upward *** most surface movement(i.e., subsidence) occurs in the months and years after mining by the longwall method, surface movement still occurs many decades after mining is *** the closure and flooding of underground excavations and surrounding rock, this movement was *** paper focuses on quantifying the upward movement in two neighboring coal mines(Winterslag and Zwartberg, Belgium).The study is based on data from a remote sensing technique: interferometry with synthetic aperture radar(INSAR).The results of the study show that the rate of upward movement in the decade after closure is about 10 mm/year on *** upward movements are not linked directly to the past exploitation directly underneath a *** amounts of subsidence at specific locations are linked mainly to their positions relative to an inverse trough shape situated over the entire mined-out areas and their immediate *** features, such as geological faults, can have a secondary effect on the local variation of the *** processes of subsidence and uplift are based on completely different *** is initiated by a caving process, while the process of uplift is clearly linked to flooding.

关键词： Coal mining Surface movement Subsidence Uplift Radar-interferometry

Cobalt-embedded 3D conductive honeycomb architecture to enable high-sulphur-loading Li-S batteries under lean electrolyte conditions

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Nano Research 2022年第9期15卷 8091-8100页

作者： Hui Pan Zhibin Cheng Jan Fransaer Jiangshui Luo Michael Wübbenhorst Laboratory for Soft Matter and Biophysics Department of Physics and AstronomyKU LeuvenLeuven 3001Belgium Fujian Key Laboratory of Polymer Materials College of Chemistry and Materials ScienceFujian Normal UniversityFuzhou 350007China Department of Materials Engineering KU LeuvenLeuven 3001Belgium Lab of Electrolytes and Phase Change Materials College of Materials Science and EngineeringSichuan UniversityChengdu 610065China

High sulphur loading and lean electrolyte conditions are important to achieve the high theoretical energy density of lithiumsulphur(Li-S)***,serious problems such as low sulphur utilization and fast capacity fade are typically experienced under low electrolyte/sulphur(E/S)ratios and high sulphur loading *** address these issues,a cobaltcontaining three-dimensional conductive honeycomb(Co@N-HPC)is proposed in this work as a material for sulphur *** good electrical conductivity and high density of catalytic sites of(Co@N-HPC)allow fast redox kinetics of lithium polysulfide(LiPS)in high-sulphur-loading *** addition,the hierarchical structure and good wettability by the electrolyte of Co@NHPC facilitates electrolyte penetration and LiPS conversion,leading to a high utilization of sulphur under lean electrolyte ***,at a current density of 0.2 C,a volumetric capacity of 1,410 mAh·cm^(−3)was attained with a sulphur loading of 5.1 mg·cm^(−2)and an E/S ratio of 5μL·mg^(−1).This work provides ideas for the development of lean electrolyte Li-S batteries with a high sulphur loading.

关键词： honeycomb architecture cobalt nanoparticles high sulphur loading lean electrolyte lithium-sulphur battery

RMA-CNN:A Residual Mixed Domain Attention CNN for Bearings Fault Diagnosis and Its Time-Frequency Domain Interpretability

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Journal of Dynamics, Monitoring and Diagnostics 2023年第2期2卷 115-132页

作者： Dandan Peng Huan Wang Wim Desmet Konstantinos Gryllias Department of Mechanical Engineering Faculty of Engineering ScienceKU LeuvenLeuvenBelgium Flanders Make@ku leuven Celestijnenlaan 300BOX 24203001 LeuvenBelgium Department of Industrial Engineering Tsinghua UniversityBeijing 100084China leuven.AI–ku leuven Institute for AI B-3000LeuvenBelgium

Early fault diagnosis of bearings is crucial for ensuring safe and reliable *** neural networks(CNNs)have achieved significant breakthroughs in machinery fault ***,complex and varying working conditions can lead to inter-class similarity and intra-class variability in datasets,making it more challenging for CNNs to learn discriminative ***,CNNs are often considered“black boxes”and lack sufficient interpretability in the fault diagnosis *** address these issues,this paper introduces a residual mixed domain attention CNN method,referred to as *** method comprises multiple residual mixed domain attention modules(RMAMs),each employing one attention mechanism to emphasize meaningful features in both time and channel *** significantly enhances the network’s ability to learn fault-related ***,we conduct an in-depth analysis of the inherent feature learning mechanism of the attention module RMAM to improve the interpretability of CNNs in fault diagnosis *** conducted on two datasets—a high-speed aeronautical bearing dataset and a motor bearing dataset—demonstrate that the RMA-CNN achieves remarkable results in diagnostic tasks.

关键词： attention interpretability CNN fault diagnosis rolling element bearings

Dendritic shrinkage after injury: a cellular killer or a necessity for axonal regeneration?

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Neural Regeneration Research 2019年第8期14卷 1313-1316页

作者： An Beckers Lieve Moons Neural Circuit Development and Regeneration Research Group Department of BiologyKU Leuven

Dendrites form an essential component of the neuronal circuit have been largely overlooked in regenerative research. Nevertheless, subtle changes in the dendritic arbors of neurons are one of the first stages of various neurodegenerative diseases, leading to dysfunctional neuronal networks and ultimately cellular death. Maintaining dendrites is therefore considered an essential neuroprotective strategy. This mini-review aims to discuss an intriguing hypothesis, which postulates that dendritic shrinkage is an important stimulant to boost axonal regeneration, and thus that preserving dendrites might not be the ideal therapeutic method to regain a full functional network upon central nervous system damage. Indeed, our study in zebrafish, a versatile animal model with robust regenerative capacity recently unraveled that dendritic retraction is evoked prior to axonal regrowth after optic nerve injury. Strikingly, inhibiting dendritic pruning upon damage perturbed axonal regeneration. This constraining effect of dendrites on axonal regrowth has sporadically been proposed in literature, as summarized in this short narrative. In addition, the review discusses a plausible underlying mechanism for the observed antagonistic axon-dendrite interplay, which is based on energy restriction inside neurons. Axonal injury indeed leads to a high local energy demand in which efficient axonal energy supply is fundamental to ensure regrowth. At the same time, axonal lesion is known to induce m让ochondrial depolarization, causing energy depletion in the axonal compartment of damaged neurons. Mitochondria, however, become mostly stationary after development, which has been proposed as a potential underlying reason for the low regenerative capacity of adult mammals. Per contra, upon reduced neuronal activity, mitochondrial mobility enhances. In this view, dendritic shrinkage after axonal injury in zebrafish could result in less synaptic input and hence, a release of mitochondria within the so

关键词： axonal regeneration dendritic remodeling retina central nervous system zebrafish mitochondrial transport mitochondrial dynamics energy supply

Motor inhibition efficiency in healthy aging: the role of γ-aminobutyric acid

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Neural Regeneration Research 2019年第5期14卷 741-744页

作者： Lisa Pauwels Celine Maes Lize Hermans Stephan P.Swinnen ku leuven Movement Control and Neuroplasticity Research Group Department of Movement Sciences Group Biomedical Sciences leuven Brain Institute (LBI)

The ability to cancel a motor response is critical for optimal functioning in various facets of daily life. Hence, efficient inhibitory motor control is a key function throughout the lifespan. Considering the fact that inhibitory motor function gradually declines with advancing age, it is not surprising that the study of motor inhibition in this age group is gaining considerable interest. In general, we can distinguish between two prominent types of motor inhibition, namely proactive and reactive inhibition. Whereas the anticipation for upcoming stops(proactive inhibition) appears readily preserved at older age, the ability to stop an already planned or initiated action(reactive inhibition) generally declines with advancing age. The differential impact of aging on proactive and reactive inhibition at the behavioral level prompts questions about the neural architecture underlying both types of inhibitory motor control. Here we will not only highlight the underlying structural brain properties of proactive and reactive inhibitory control but we will also discuss recent developments in brain-behavioral approaches, namely the registration of neurochemical compounds using magnetic resonance spectroscopy. This technique allows for the direct detection of the primary inhibitory neurotransmitter in the brain, i.e., γ-aminobutyric acid, across the broader cortical/subcortical territory, thereby opening new perspectives for better understanding the neural mechanisms mediating efficient inhibitory control in the context of healthy aging. Ultimately, these insights may contribute to the development of interventions specifically designed to counteract age-related declines in motor inhibition.

关键词： proactive inhibition reactive inhibition motor inhibition healthy aging gamma-aminobutyric acid magnetic resonance spectroscopy GABA inhibitory neurotransmitter neuroimaging

Multi-criteria decision making methods to address rural land allocation problems:A systematic review

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International Soil and Water Conservation Research 2021年第4期9卷 490-501页

作者： Sintayehu Legesse Gebre Dirk Cattrysse Esayas Alemayehu Jos Van Orshoven Department of Mechanical Engineering Center for Industrial ManagementTraffic&InfrastructureKU Leuven(University of Leuven)Celestijnenlaan 3003001LeuvenBelgium Department of Earth and Environmental Sciences Division of ForestNature and LandscapeKU Leuven(University of Leuven)Celestijnenlaan 200E3001LeuvenBelgium Department of Natural Resource Management Jimma UniversityJimmaEthiopia Department of Civil and Environmental Engineering JITJimma UniversityJimmaEthiopia

Land allocation has been an important issue in land use planning research *** allocation involves different multifunctional activities of maximizing environmental,economic and social ***-criteria decision making(MCDM)method is the most popular tool to optimize land allocation problems by considering decision variables,conflicting objectives,and ***,decision-makers face problems on how to optimize the land allocation while minimizing the conflicting trade-offs existing in the decision *** this review study,we aim at identifying and extracting information on MCDM methods to solve land allocation problems from English language articles published between 2000 and 2019 and indexed by four scientific literature databases(Web of Science,Science Direct,Scopus,Google scholar).To this end,we applied a systematic literature review approach,*** Preferred Reporting Items for Systematic Reviews and Meta-Analysis procedure(Moher et al.,2009),with a structured database search expression.120 articles were selected of which,after careful screening of title,keywords and abstract,69 were retained for detailed *** review study report compiles comprehensive information by classifying the papers into application area,optimization objectives,criteria used,decision techniques,publication year and study *** summary,we found that in the last two decades,the use of the MCDM method has increased,particularly in Europe and ***(analytical hierarchal process)is frequently used for multi-attribute land allocation problems with reference to ecotourism and ecosystem ***(linear programming)and SA(simulating annealing)methods are predominantly used to optimize multi-objectives complex agricultural and forest land allocation problems respectively.

关键词： Database Allocation Decision techniques PRISMA

Visualizing light-induced dynamic structural transformations of Au clusters-based photocatalyst via in situ TEM

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Nano Research 2021年第8期14卷 2805-2809页

作者： Bo Weng Youhong Jiang Hong-Gang Liao Maarten B.J.Roeffaers Feili Lai Haowei Huang Zichao Tang State Key Laboratory for Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy MaterialsCollege of Chemistry and Chemical Engineering Xiamen UniversityXiamen 361005China cMACS Department of Microbial and Molecular SystemsKU LeuvenCelestijnenlaan 200F3001 LeuvenBelgium Department of Chemistry KU LeuvenCelestijnenlaan 200F3001 LeuvenBelgium

Ultrasmall gold(Au)clusters have been regarded as one of the prototypes materials for solar energy conversion due to their unique strong molecular-like light absorption ***,the light-induced aggregation of Au clusters into nanoparticles is one of the most important factors that restricts its application in *** Au clusters aggregation has been widely demonstrated,the underlying mechanism for cluster fusion is still unclear due to the lack of experimental ***,we report the direct observation of Au clusters on TiO_(2) nanosheets aggregating when used as visible light photocatalysts for the reduction of *** in situ high-resolution transmission electron microscopy(TEM),the coexistence of two fusion mechanisms of Au clusters on TiO_(2) under ultraviolet-visible(UV-Vis)light irradiation in air is identified,i.e.,the migration and coalescence(MC)and Ostwald ripening(OR).Additionally,the correlation between the photostability of Au clusters and reaction atmospheres has been investigated,among which Au clusters have higher stability in an inert N_(2) atmosphere or vacuum than the oxidizing atmospheres(i.e.,air and O_(2)).These results indicate the inherent stability of Au cluster during photocatalysis,and instability comes from the consuming of ligand *** work not only discloses the underlying mechanism of Au cluster sintering but also provides guidelines for enhancing metal clusters-based photocatalysts stability.

关键词： photocatalysis dynamic structural transformation Au clusters in situ TEM