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On the calibration of a shear stress criterion for rock joints to represent the full stress-strain profile

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 379-392页

作者： Akram deiminiat Jonathan d.Aubertin Yannic Ethier department of Construction Engineering École de Technologie Supérieure(ÉTS)MontréalCanada

Conventional numerical solutions developed to describe the geomechanical behavior of rock interfaces subjected to differential load emphasize peak and residual shear *** detailed analysis of preand post-peak shear stress-displacement behavior is central to various time-dependent and dynamic rock mechanic problems such as rockbursts and structural instabilities in highly stressed *** complete stress-displacement surface(CSdS)model was developed to describe analytically the pre-and post-peak behavior of rock interfaces under differential *** formulations of the CSdS model required extensive curve-fitting iterations which limited its practical applicability and transparent integration into engineering *** present work proposes modifications to the CSdS model aimed at developing a comprehensive and modern calibration protocol to describe the complete shear stressdisplacement behavior of rock interfaces under differential *** proposed update to the CSdS model incorporates the concept of mobilized shear strength to enhance the post-peak ***’s concepts of joint roughness coefficient(JRC)and joint compressive strength(JCS)are incorporated to facilitate empirical estimations for peak shear stress and normal closure ***/uniaxial compression test and direct shear test results are used to validate the updated model and exemplify the proposed calibration *** results illustrate that the revised model successfully predicts the post-peak and complete axial stressestrain and shear stressedisplacement curves for rock joints.

关键词： Full shear profile Post-peak shear behavior Rock joint Joint roughness coefficient(JRC) Axial stress-strain curve

Connecting cellular mechanisms and extracellular vesicle cargo in traumatic brain injury

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Neural Regeneration Research 2024年第10期19卷 2119-2131页

作者： Nikita Ollen-Bittle Austyn d.Roseborough Wenxuan Wang Jeng-liang d.Wu Shawn N.Whitehead department of Anatomy and Cell Biology Western UniversityLondonONCanada Schulich School of Medicine and dentistry Western UniversityLondonONCanada deparment of Clinical Neurological Sciences Western UniversityLondonONCanada

Traumatic brain injury is followed by a cascade of dynamic and complex events occurring at the cellular level. These events include: diffuse axonal injury, neuronal cell death, blood-brain barrier break down, glial activation and neuroinflammation, edema, ischemia, vascular injury, energy failure, and peripheral immune cell infiltration. The timing of these events post injury has been linked to injury severity and functional outcome. Extracellular vesicles are membrane bound secretory vesicles that contain markers and cargo pertaining to their cell of origin and can cross the blood-brain barrier. These qualities make extracellular vesicles intriguing candidates for a liquid biopsy into the pathophysiologic changes occurring at the cellular level post traumatic brain injury. Herein, we review the most commonly reported cargo changes in extracellular vesicles from clinical traumatic brain injury samples. We then use knowledge from animal and in vitro models to help infer what these changes may indicate regrading cellular responses post traumatic brain injury. Future research should prioritize labeling extracellular vesicles with markers for distinct cell types across a range of timepoints post traumatic brain injury.

关键词： axonal injury biomarkers blood-brain barrier chronic traumatic encephalopathy extracellular vesicles glial activation neuroinflammation traumatic brain injury

Sex differences in Alzheimer's disease:an urgent research venue to follow

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Neural Regeneration Research 2024年第12期19卷 2569-2570页

作者： Raquel Jiménez-Herrera Ana Contreras Juan d.Navarro-López Lydia Jiménez-díaz Neurophysiology&Behavior Lab University of Castilla-La ManchaSchool of Medicine of Ciudad RealCiudad RealSpain

due to increasing life expectancy,the amount of people with dementia worldwide is expected to experience a substantial rise,with estimates indicating a growth from 55 million in 2019 to a staggering 139 million by the... 详细信息

关键词： Alzheimer predominant estimates

MART(Splitting-Merging Assisted Reliable)Independent Component Analysis for Extracting Accurate Brain Functional Networks

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Neuroscience Bulletin 2024年第7期40卷 905-920页

作者： Xingyu He Vince d.Calhoun Yuhui du School of Computer and Information Technology Shanxi UniversityTaiyuan 030006China Tri-Institutional Center for Translational Research in Neuroimaging and data Science Georgia State UniversityGeorgia Institute of TechnologyEmory UniversityAtlanta 30303USA

Functional networks(FNs)hold significant promise in understanding brain *** component analysis(ICA)has been applied in estimating FNs from functional magnetic resonance imaging(fMRI).However,determining an optimal model order for ICA remains challenging,leading to criticism about the reliability of FN ***,we propose a SMART(splitting-merging assisted reliable)ICA method that automatically extracts reliable FNs by clustering independent components(ICs)obtained from multi-model-order ICA using a simplified graph while providing linkages among FNs deduced from different-model *** extend SMART ICA to multi-subject fMRI analysis,validating its effectiveness using simulated and real fMRI *** on simulated data,the method accurately estimates both group-common and group-unique components and demonstrates robustness to *** two age-matched cohorts of resting fMRI data comprising 1,950 healthy subjects,the resulting reliable group-level FNs are greatly similar between the two cohorts,and interestingly the subject-specific FNs show progressive changes while age ***,both small-scale and large-scale brain FN templates are provided as benchmarks for future *** together,SMART ICA can automatically obtain reliable FNs in analyzing multi-subject fMRI data,while also providing linkages between different FNs.

关键词： Independent component analysis Functional magnetic resonance imaging-Brain functional networks Clustering Multi-model-order

Are population cycles recovering?

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Integrative Zoology 2024年第3期19卷 538-547页

作者： Vasily d.YAKUSHOV Boris I.SHEFTEL A.N.Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences MoscowRussia

The dynamics of populations of small mammals of Central Siberia was *** studies were carried out at the Yenisei ecological station“Mirnoye”of the *** Institute of Ecology and Evolution,Russian Academy of *** time series analysis was performed by the wavelet transform using the statistical data processing language *** the 20th century,the dynamics of the population of the community and some of its constituent species(Sorex araneus;***;***;***;***;Craseomys rufocanus;Clethrionomys rutilus;Microtus oeconomus;***)were characterized by a 4-year *** type of dynamics changed to noncyclic by the nineties,but by 2022,four species(***,***,***,and ***)and the community as a whole showed a tendency toward recovery of population *** remaining species were characterized by consistently low numbers with irregular low amplitude fluctuations.

关键词： population cycles small mammals time-series analysis wavelet transform

Highly toxic Aβ begets more Aβ

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Neural Regeneration Research 2024年第9期19卷 1871-1872页

作者： Merc M.Kemeh Noel d.Lazo Gustaf H.Carlson School of Chemistry and Biochemistry Clark UniversityWorcesterMAUSA

Alzheimer’s disease(Ad)is the most common form of dementia-the 7th leading cause of death *** the tissue level,Ad is characterized by the presence of extracellular amyloid plaques that are comprised primarily of the amyloid-βpeptide(Aβ),and by intraneuronal neurofibrillary tangles composed of *** genetics of early-onset Ad and longitudinal brain-imaging studies of late-onset Ad indicate that extracellular Aβdeposition,in general,precedes neurofibrillary tangle formation in neurons(Hampel et al.,2021;Young-Pearse et al.,2023).

关键词： Aβ tau Alzheimer death

The multi-impurity system in CdSe nanoplatelets:electronic structure and thermodynamic properties

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Communications in Theoretical Physics 2024年第3期76卷 165-173页

作者： d A Baghdasaryan V A Harutynyan E M Kazaryan H A Sarkisyan Russian-Armenian University H Emin 1230051YerevanArmenia Institute of Applied Problems of Physics 25 Nersisyan St0014YerevanArmenia

This paper theoretically studies the impurity states and the effects of impurity concentration and configuration on the optical,electrical,and statistical properties of CdSe nanoplatelets(NPLs).An image charge-based model of electron-impurity interaction is *** charge-carrier energy spectra and corresponding wave functions depending on the impurity number and configuration are *** electron binding energies are calculated for different NPL *** is shown that the image charge-based interaction potential that arises due to the dielectric constants mismatch is much stronger than the interaction potential that does not take such a mismatch into ***,it is demonstrated that the binding energies are increasing with the number of *** calculate the canonical partition function using the energy levels of the electron,which in turn is used to obtain the mean energy,heat capacity,and entropy of the non-interacting electron *** thermodynamic properties of the non-interacting electron gas that depend on the geometric parameters of the NPL,impurity number,configuration,and temperature are studied.

关键词： nanoplateletes thermodynamic properties impurity states

Near resonance vibration isolation on a levered-dual response(LEdAR)Coulomb-damped system by differential preloads/offsets in linear springs

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1033-1050页

作者： T.I.TOLUWALOJU C.K.THEIN d.HALIM department of Mechanical Materials and Manufacturing EngineeringUniversity of Nottingham Ningbo ChinaNingbo 315100Zhejiang ProvinceChina Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute University of Nottingham Ningbo ChinaNingbo 315048Zhejiang ProvinceChina

The levered-dual response(LEdAR)Coulomb-damped system attains near resonant vibration isolation by differential preloads/offsets in linear *** takes the advantages of both the preloads/offsets in linear springs and the guiderail friction for realizing different levels of vibration *** isolation capacities are investigated on the strategies with both the horizontal and vertical guiderails,with the horizontal rail only,and without *** compressive preloads generally result in the consumption of most of the initial excitation energy so as to overcome the potential *** isolation onsets at the frequency ratio of 1∓0.095 on the left-hand side(LHS)and the right-hand side(RHS)of the lever are relative to the load plate *** observed near resonant isolation thus makes the LEdAR system a candidate for the isolation of the mechanical systems about resonance while opening a path for simultaneous harvesterisolation functions and passive functions at extreme frequencies.

关键词： lever ratio Coulomb damping preload tension/compression isolation band/depth offset potential

Application of flame-formed carbon nanoparticle films for ethanol sensing Author links open overlay panel

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Particuology 2024年第8期91卷 202-210页

作者： Pegah darvehi Luca Basta Mario Commodo Patrizia Minutolo Andrea d'Anna Istituto di Scienze e Tecnologie per l’Energia e la MobilitàSostenibili Consiglio Nazionale delle RicercheP.le Tecchio 8080125NapoliItaly dipartimento di Ingegneria Chimica dei Materiali e della Produzione IndustrialeUniversitàdegli Studi di Napoli Federico IIP.le Tecchio 8080125NapoliItaly

Carbon nanoparticles(CNPs)have received considerable attention due to their exceptional qualities and *** unique physical and chemical characteristics make them extremely intriguing as materials for numerous high-potential applications,such as electronics and gas *** study focused on producing carbon-based nanomaterial devices by deposition of flame-formed carbon nanoparticles on a suitable substrate and investigating their gas-sensing *** were produced in a fuel-rich laminar premixed ethylene/air flame and the collected CNP film was morphologically and electrically *** electrical conductivity of the film was investigated as a function of ethanol concentration and amount of deposited ***,CNP films exhibited high sensitivity to ambient ethanol gas concentrations,and rapid recovery times at room temperature,and showed a sensitivity increasing with the amount of deposited material and the surface *** findings demonstrate the high potential of combustion-generated CNPs as building materials for low-cost and portable ethanol sensors.

关键词： Flame synthesis Carbon nanoparticles Soot Nanostructured thin film Optical and electrical characterization Atomic force microscopy Sensors