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3D finite element modelling of multilateral junction wellbore stability

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Petroleum Science 2018年第4期15卷 801-814页

作者： Assef Mohamad-Hussein Juliane heiland Schlumberger Geomechanics Center of ExcellenceBuckingham Gate

Wellbore failure can occur at different stages of operations. For example, wellbore collapse might happen during drilling and/or during production. The drilling process results in the removal of an already stressed rock material. If the induced stresses near the wellbore exceed the strength of rock, wellbore failure occurs. The production process also changes the effective stresses around the wellbore. Such changes in stresses can be significant for high drawdown pressures and can trigger wellbore failure. In this paper, the Mohr–Coulomb failure criterion with a hyperbolic hardening is used. The model parameters are identified from triaxial compression tests. The numerical simulations of laboratory tests showed that the model can reproduce the mechanical behaviour of sandstone. In addition, the simulations of multilateral junction stability experiments showed that the model was able to reproduce yielding and failure at the multilateral junction for different levels of applied stresses. Finally, a numerical example examining multilateral junction stability in an open borehole during drilling and production is presented. The results illustrate the development of a localized failure zone proximate to the area where two wellbore tracks join, particularly on the side with a sharp approaching angle, which would significantly increase the risk of wellbore collapse at the junction.

关键词： Multilateral junction Numerical modelling Stability

Machine Learning Techniques in Predicting Hot Deformation Behavior of Metallic Materials

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 713-732页

作者： Petr Opela Josef Walek Jaromír Kopecek Department of Metallurgical Technologies Faculty of Materials Science and TechnologyVSB–Technical University of OstravaOstrava70800Czech Republic FZU—Institute of Physics of the Czech Academy of Sciences Prague18200Czech Republic

In engineering practice,it is often necessary to determine functional relationships between dependent and independent *** relationships can be highly nonlinear,and classical regression approaches cannot always provide sufficiently reliable ***,Machine Learning(ML)techniques,which offer advanced regression tools to address complicated engineering issues,have been developed and widely *** study investigates the selected ML techniques to evaluate their suitability for application in the hot deformation behavior of metallic *** ML-based regression methods of Artificial Neural Networks(ANNs),Support Vector Machine(SVM),Decision Tree regression(DTr),and Gaussian Process regression(GPr)are applied to mathematically describe hot flow stress curve datasets acquired experimentally for a medium-carbon *** the GPr method has not been used for such a regression task before,the results showed that its performance is the most favorable and practically unrivaled;neither the ANN method nor the other studied ML techniques provide such precise results of the solved regression analysis.

关键词： Machine learning Gaussian process regression artificial neural networks support vector machine hot deformation behavior

Emerging potential of progranulin-dependent SorCS2 signaling in healthy and diseased nervous systems

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Neural regeneration research 2025年第9期20卷 2591-2593页

作者： Alena Salasova Anders Nykjær Danish research Institute of Translational Neuroscience DANDrITE-Nordic EMBL Partnership for Molecular Medicine and Centre of Excellence PROMEMODepartment of BiomedicineAarhus UniversityAarhusDenmark

The formation of the mammalian nervous system and its maturation into sensory,motor,cognitive,and behavioral circuits is a complex process that begins during early embryogenesis and lasts until young *** neurodevelopm... 详细信息

关键词： progr jointly CS2

A comprehensive investigation on nonlinear vibration and bending characteristics of bio-inspired helicoidal laminated composite structures

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 81-100页

作者： S.SAUrABH r.KIrAN D.SINGH r.VAISH V.S.CHAUHAN School of Mechanical and Materials Engineering Indian Institute of Technology Mandi

Bio-inspired helicoidal composite laminates, inspired by the intricate helical structures found in nature, present a promising frontier for enhancing the mechanical properties of structural designs. Hence, this study provides a comprehensive investigation into the nonlinear free vibration and nonlinear bending behavior of bio-inspired composite plates. The inverse hyperbolic shear deformation theory(IHSDT) of plates is employed to characterize the displacement field, with the incorporation of Green-Lagrange nonlinearity. The problem is modeled using the C0finite element method(FEM), and an in-house code is developed in the MATLAB environment to solve it numerically. Various helicoidal layup configurations including helicoidal recursive(Hr), helicoidal exponential(HE), helicoidal semi-circular(HS), linear helicoidal(LH), and Fibonacci helicoidal(FH)with different layup sequences and quasi-isotropic configurations are studied. The model is validated, and parametric studies are conducted. These studies investigate the effects of layup configurations, side-to-thickness ratio, modulus ratios, boundary conditions, and loading conditions at different load amplitudes on the nonlinear vibration and nonlinear bending behaviors of bio-inspired composite plates. The results show that the laminate sequence exerts a substantial impact on both nonlinear natural frequencies and nonlinear bending behaviors. Moreover, this influence varies across different side-to-thickness ratios and boundary conditions of the bio-inspired composite plate.

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Antisense oligonucleotides provide optimism to the therapeutic landscape for tauopathies

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Neural regeneration research 2025年第3期20卷 803-804页

作者： Glenn A.Harris Lauren r.Hirschfeld rainwater Charitable Foundation Fort WorthTXUSA

Tauopathies are a group of neurodegenerative diseases characterized by abnormal metabolism of the misfolded tau protein. Tau is encoded by the microtubule-associated protein tau gene(MAPT) and can be classified as either 3-repeat(3r) or 4-repeat(4r) based on the number of repeat domains from alternative splicing of exon 10 of the MAPT gene.

关键词： tau metabolism diseases

Differentiation of periapical granulomas and cysts by using dental MrI: a pilot study

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International Journal of Oral Science 2018年第3期10卷 152-159页

作者： Alexander Juerchott Thorsten Pfefferle Christa Flechtenmacher Johannes Mente Martin Bendszus Sabine heiland Tim Hilgenfeld Department of Neuroradiology Heidelberg University Hospital Division of Endodontics and Dental Traumatology Department of Conservative Dentistry Heidelberg University Hospital Institute of Pathology Heidelberg University Hospital Division of Experimental radiology Department of Neuroradiology Heidelberg University Hospital

The purpose of this pilot study was to evaluate whether periapical granulomas can be differentiated from periapical cysts in vivo by using dental magnetic resonance imaging(MrI). Prior to apicoectomy, 11 patients with radiographically confirmed periapical lesions underwent dental MrI, including fat-saturated T2-weighted(T2 wFS) images, non-contrast-enhanced T1-weighted images with and without fat saturation(T1 w/T1 wFS), and contrast-enhanced fat-saturated T1-weighted(T1 wFS+C) images. Two independent observers performed structured image analysis of MrI datasets twice. A total of 15 diagnostic MrI criteria were evaluated, and histopathological results(6 granulomas and 5 cysts) were compared with MrI characteristics. Statistical analysis was performed using intraclass correlation coefficient(ICC), Cohen’s kappa(κ), Mann–Whitney U-test and Fisher’s exact test. Lesion identification and consecutive structured image analysis was possible on T2 wFS and T1 wFS+C MrI images. A high reproducibility was shown for MrI measurements of the maximum lesion diameter(intraobserver ICC = 0.996/0.998; interobserver ICC = 0.997), for the "peripheral rim" thickness(intraobserver ICC = 0.988/0.984; interobserver ICC = 0.970), and for all non-quantitative MrI criteria(intraobserver-κ = 0.990/0.995; interobserver-κ = 0.988). In accordance with histopathological results, six MrI criteria allowed for a clear differentiation between cysts and granulomas:(1) outer margin of lesion,(2) texture of "peripheral rim" in T1 wFS+C,(3)texture of "lesion center" in T2 wFS,(4) surrounding tissue involvement in T2 wFS,(5) surrounding tissue involvement in T1 wFS+C and(6) maximum "peripheral rim" thickness(all: P radiation-free dental MrI enables a reliable differentiation between periapical cysts and granulomas in vivo. Thus, MrI may substantially improve treatment strategies and help to avoid unnecessary surgery in apical periodontitis.

关键词： Differentiation of periapical granulomas and cysts by using dental MrI a pilot study

Heterogeneity of mature oligodendrocytes in the central nervous system

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Neural regeneration research 2025年第5期20卷 1336-1349页

作者： Chao Weng Adam M.r.Groh Moein Yaqubi Qiao-Ling Cui Jo Anne Stratton G.r.Wayne Moore Jack P.Antel Neuroimmunology Unit Montreal Neurological Institute-HospitalDepartment of Neurology and NeurosurgeryMcGill UniversityMontrealQCCanada Department of Neurology Renmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina

Mature oligodendrocytes form myelin sheaths that are crucial for the insulation of axons and efficient signal transmission in the central nervous *** evidence has challenged the classical view of the functionally static mature oligodendrocyte and revealed a gamut of dynamic functions such as the ability to modulate neuronal circuitry and provide metabolic support to *** the recognition of potential heterogeneity in mature oligodendrocyte function,a comprehensive summary of mature oligodendrocyte diversity is *** delve into early 20th-century studies by robertson and río-Hortega that laid the foundation for the modern identification of regional and morphological heterogeneity in mature ***,recent morphologic and functional studies call into question the long-assumed homogeneity of mature oligodendrocyte function through the identification of distinct subtypes with varying myelination ***,modern molecular investigations,employing techniques such as single cell/nucleus rNA sequencing,consistently unveil at least six mature oligodendrocyte subpopulations in the human central nervous system that are highly transcriptomically diverse and vary with central nervous system *** and disease related mature oligodendrocyte variation denotes the impact of pathological conditions such as multiple sclerosis,Alzheimer's disease,and psychiatric ***,caution is warranted when subclassifying mature oligodendrocytes because of the simplification needed to make conclusions about cell identity from temporally confined *** studies leveraging advanced techniques like spatial transcriptomics and single-cell proteomics promise a more nuanced understanding of mature oligodendrocyte *** research avenues that precisely evaluate mature oligodendrocyte heterogeneity with care to understand the mitigating influence of species,sex,central nervous system region,age,and disease,

关键词： aging central nervous system diseases electron microscopy heterogeneity immunohistochemistry myelin sheath natural history neuroglia oligodendroglia single-cell gene expression analysis

real-world evidence for improved outcomes with histamine antagonists and aspirin in 22,560 COVID-19 patients

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Signal Transduction and Targeted Therapy 2021年第8期6卷 2297-2299页

作者： Cameron Mura Saskia Preissner Susanne Nahles Max heiland Philip E.Bourne robert Preissner School of Data Science and Deportment of Biomedical Engineering University of VirginiaCharlottesvilleVAUSA Department Oral and Maxillofacial Surgery Charite-Universitatsmedizin Berlincorporate member of Freie Universitat BerlinHumboldt-Universitat zu Berlinand Berlin Institute of HealthBerlinGermany Institute of Physiology and Science-IT Charite-Universitatsmedizin Berlincorporate member of Freie Universitat BerlinHumboldt-Universitat zu Berlinand Berlin Institute of HealthBerlinGermany

Dear Editor,The COVID-19 pandemic has driven great interest in the therapeutic potential of repurposed drugs with well-established benefits and safety profiles(toxicity,bioavailability,etc.),many of which act via sign... 详细信息

关键词： drugs category COV

Spastin and alsin protein interactome analyses begin to reveal key canonical pathways and suggest novel druggable targets

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Neural regeneration research 2025年第3期20卷 725-739页

作者： Benjamin r.Helmold Angela Ahrens Zachary Fitzgerald P.Hande Ozdinler Department of Neurology Feinberg School of MedicineNorthwestern UniversityChicagoILUSA Center for Molecular Innovation and Drug Discovery Center for Developmental TherapeuticsChemistry of Life Processes InstituteNorthwestern UniversityEvanstonILUSA Mesulam Center for Cognitive Neurology and Alzheimer’s Disease Feinberg School of MedicineNorthwestern UniversityChicagoILUSA Feinberg School of Medicine Les Turner ALS Center at Northwestern UniversityChicagoILUSA

Developing effective and long-term treatment strategies for rare and complex neurodegenerative diseases is challenging. One of the major roadblocks is the extensive heterogeneity among patients. This hinders understanding the underlying disease-causing mechanisms and building solutions that have implications for a broad spectrum of patients. One potential solution is to develop personalized medicine approaches based on strategies that target the most prevalent cellular events that are perturbed in patients. Especially in patients with a known genetic mutation, it may be possible to understand how these mutations contribute to problems that lead to neurodegeneration. Protein–protein interaction analyses offer great advantages for revealing how proteins interact, which cellular events are primarily involved in these interactions, and how they become affected when key genes are mutated in patients. This line of investigation also suggests novel druggable targets for patients with different mutations. Here, we focus on alsin and spastin, two proteins that are identified as “causative” for amyotrophic lateral sclerosis and hereditary spastic paraplegia, respectively, when mutated. Our review analyzes the protein interactome for alsin and spastin, the canonical pathways that are primarily important for each protein domain, as well as compounds that are either Food and Drug Administration–approved or are in active clinical trials concerning the affected cellular pathways. This line of research begins to pave the way for personalized medicine approaches that are desperately needed for rare neurodegenerative diseases that are complex and heterogeneous.

关键词： ALS2 alsin amyotrophic lateral sclerosis hereditary spastic paraplegia neurodegenerative diseases personalized medicine precision medicine protein interactome protein-protein interactions SPAST spastin