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Particuology 2009年第6期7卷 438-444页

作者： Dario T.Beruto alberto lagazzo Rodolfo Botter Roberto Grillo Department of Civil Environmental and Architectural Engineering (DICAT)University of GenoaP.le Kennedy (Fiera del Mare)Pad. D16129-GenoaItaly Artigo S.p.A. loc.Carpeneto17014-Cairo Montenotte (SV)Italy

Rheologicat measurements of four colloidal kaolin powders dispersed in water, paraffinic oil and liquid rubber have been done at solid concentration （9 （VS/VL） in the range 8-33%. In quasi-static conditions the yield stress τ° values were derived. An S-shaped relationship between τ° and （9 exists, that allows to evaluate the percolation threshold θc values. In water θc ranges between 29% and 33%, while it is between 17% and 21% in oil and in liquid rubber. In water the microstructure units, i.e. the primary clusters among kaolin crystallites, are denser and bigger than the ones in the two other liquids. Furthermore, in quasistatic condition, the aqueous microstructure units have less tendency to cling together to form a network that can span all over the liquid phase. The different kaolin dispersions at θ equal to 22% are characterized by yield stress ranging between 7.S Pa and 59 Pa in water, 66-250 Pa in oil and 230-770 Pa in liquid rubber. It has been found that for any kaolin types the log τ°/ θ evaluated near to the percolation threshold is a conservative parameter of the three different liquids. These results are useful to design colloidal dispersions with selected microstructure.

关键词： Yield stress Colloid Dispersions Microstructure units Cluster Kaolin Rheology

An experimental model of vitreous motion induced by eye rotations

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Eye and Vision 2015年第1期2卷 85-94页

作者： Andrea Bonfiglio alberto lagazzo Rodolfo Repetto Alessandro Stocchino Department of Civil Chemical and Environmental EngineeringUniversity of GenoaItalyVia Montallegro 116145 GenoaItaly

Background:During eye rotations the vitreous humour moves with respect to the eye *** relative motion has been suggested to possibly have an important role in inducing degradation of the gel structure,which might lead to vitreous liquefaction and/or posterior vitreous *** of the present work is to study the characteristics of vitreous motion induced by eye ***:We use an experimental setup,consisting of a Perspex model of the vitreous chamber that,for simplicity,is taken to have a spherical *** model is filled with an artificial vitreous humour,prepared as a solution of agar powder and hyaluronic acid sodium salt in deionised water,which has viscoelastic mechanical properties similar to those of the real *** model rotates about an axis passing through the centre of the sphere and velocity measurements are taken on the equatorial plane orthogonal to the axis of rotation,using an optical ***:The results show that fluid viscoelasticity has a strong influence on flow *** particular,at certain frequencies of oscillation of the eye model,fluid motion can be resonantly *** means that fluid velocity within the domain can be significantly larger than that of the ***:The frequencies for which resonant excitation occurs are within the range of possible eye rotations ***,the present results suggest that resonant excitation of vitreous motion is likely to occur in ***,in turn,implies that eye rotations produce large stresses on the retina and within the vitreous that may contribute to the disruption of the vitreous gel *** present results also have implications for the choice of the ideal properties for vitreous substitute fluids.

关键词： Vitreous motion Vitreous dynamics Retinal detachment Viscoelasticity

A rheological method for selecting nano-kaolin powder as filler in SBR rubber

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Particuology 2010年第3期8卷 245-250页

作者： alberto lagazzo Sergio Lenzi Rodolfo Botter Paolo Cirillo Fabrizio Demicheli Dario T. Beruto Department of Civil Environmental and Architectural Engineering (DICAT) University of Genoa P.le Kennedy (Fiera del Mare) Pad. D 16129 Genoa Italy Artigo S.p.A. loc. Carpeneto 17014 Cairo Montenotte (SV) Italy

This paper shows that the stiffness ofstyrene-butadiene solid rubber with added kaolin powder is related to the yield stress of kaolin dispersion in liquid polybutadiene rubber up to the percolation threshold. For five kinds of kaolin powder, the value of τ° spans the range of 100-430 Pa, while the corresponding compressive elastic constant of SBR varies from 12 to 21 MPa. A relationship between τ° and △E^i^＊/ER^＊ is proposed. Critical examination of these data infers that kaolin powder dispersed in solid rubber matrix acts as an additive which decreases the random movement of the polybutadiene chains. Consequently, dispersions of nano-particles in liquid and in solid SBR are considered to be related, thus leading to a theological method for selecting nano-particles as fillers in solid SBR.

关键词： Yield stress Kaolin Filler dispersion Stiffness Styrene-butadiene rubber (SBR)Liquid polybutadieneRheology

Astrocytes, reactive astrogliosis, and glial scar formation in traumatic brain injury

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Neural Regeneration Research 2025年第4期20卷 973-989页

作者： María Belén Cieri alberto Javier Ramos Laboratorio de Neuropatología Molecular IBCN UBA-CONICETFacultad de MedicinaUniversidad de Buenos AiresBuenos AiresArgentina

Traumatic brain injury is a global health crisis,causing significant death and disability *** that follows traumatic brain injury has serious consequences for neuronal survival and cognitive impairments,with astrocytes involved in this *** traumatic brain injury,astrocytes rapidly become reactive,and astrogliosis propagates from the injury core to distant brain *** astroglial proteins are downregulated near the traumatic brain injury core,while pro-inflammatory astroglial genes are *** altered gene expression is considered a pathological remodeling of astrocytes that produces serious consequences for neuronal survival and cognitive *** addition,glial scar formed by reactive astrocytes is initially necessary to limit immune cell infiltration,but in the long term impedes axonal reconnection and functional *** therapeutic strategies for traumatic brain injury are focused on preventing acute ***,cannabinoids,progesterone,beta-blockers,and cerebrolysin demonstrate neuroprotective benefits but most of them have not been studied in the context of *** this review,we discuss the cell signaling pathways activated in reactive astrocytes following traumatic brain injury and we discuss some of the potential new strategies aimed to modulate astroglial responses in traumatic brain injury,especially using cell-targeted strategies with miRNAs or lncRNA,viral vectors,and repurposed drugs.

关键词： astrocyte glial scar innate immunity neuroinflammation stab injury Toll-like receptors

PLANNING OF DYNAMICALLY FEASIBLE TRAJECTORIES FOR TRANSLATIONAL,PLANAR,AND UNDERCONSTRAINED CABLE-DRIVEN ROBOTS

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Journal of Systems Science & Complexity 2013年第5期26卷 695-717页

作者： TREVISANI alberto Department of Management and Engineering(DTG) Universita degli Studi di PadovaStradella S.Nicola 336100 VicenzaItaly

Extensively studied since the early nineties,cable-driven robots have attracted the growing interest of the industrial and scientific community due to their desirable and peculiar *** particular,underconstrained and planar cable robots can find application in several fields,and specifically,in the packaging *** planning of dynamically feasible trajectories(i.e.,trajectories along which cable slackness and excessive tensions are avoided) is particularly challenging when dealing with such a topology of cable robots,which rely on gravity to maintain their cables in *** paper,after stressing the current relevance of cable robots,presents an extension and a generalization of a model-based method developed to translate typical cable tension bilateral bounds into intuitive limits on the velocity and acceleration of the robot end effector along a prescribed *** a new formulation of the method is based on a parametric expression of cable *** computed kinematic limits can then be incorporated into any trajectory planning *** method is developed with reference to a hybrid multi-body cable robot topology which can be functionally advantageous but worsen the problem of keeping feasible tensions in the cables both in static and dynamic *** definition of statically feasible workspace is also introduced to identify the positions where static equilibrium can be maintained with feasible ***,some aspects related to the practical implementation of the method are discussed.

关键词： Cable robot dynamically feasible trajectories statically feasible workspace trajectoryplanning.