Viscoelastic Properties of Injured and Uninjured Rat Brain Tissue

2007 ◽  
Author(s):  
Mehdi Shafieian ◽  
Kurosh Darvish
Keyword(s):  
Brain Stem ◽  
Rat Brain ◽  
Brain Tissue ◽  
Viscoelastic Material ◽  
Material Properties ◽  
Computational Models ◽  
Diffuse Axonal Injury ◽  
Elastic Response ◽  
Quasilinear Theory ◽  
The Impact

In this study, changes in the viscoelastic material properties of brain tissue due to traumatic diffuse axonal injury (DAI) were investigated. The impact acceleration model was used to generate DAI in rat brain stem. The viscoelastic material properties of brain tissue along the corticospinal (CSpT) tract in the brain stem were characterized using an indentation technique and a quasilinear theory. The results show significant reduction in the elastic response of brain tissue due to injury. In regions with significantly more DAI, larger changes in the elastic shear modulus and relaxation function were observed. These findings can improve the injury predictability of computational models of brain injury.

Changes in Viscoelastic Properties of Brain Tissue Due to Traumatic Injury

2004 ◽  
Author(s):  
Kurosh Darvish ◽  
James Stone
Keyword(s):  
Brain Tissue ◽  
Material Properties ◽  
Computational Models ◽  
Axonal Injury ◽  
Traumatic Injury ◽  
Diffuse Axonal Injury ◽  
Elastic Response ◽  
Tissue Properties ◽  
The Impact ◽  
The Brain

In this study, changes in viscoelastic material properties of brain tissue due to traumatic axonal injury (TAI) were investigated. The impact acceleration model was used to generate diffuse axonal injury in rat brain. TAI in the corticospinal (CSpT) tract in the brain stem was quantified using amyloid precursor protein immunostaining. Material properties along the CSpT were determined using an indentation technique. The results showed that the number of injured axons at the pyramidal decussation (PDx) was approximated 10 times higher than in the ponto-medullary junction (PmJ). The instantaneous elastic response was reduced approximately 70% at PDx compared to 40% at PmJ and the relaxation was uniformly reduced approximately 30%, which were attributed to the effect of injury on tissue properties. Application of a visco-elastic-plastic model that changes due to TAI can significantly alter the results of computational models of brain injury.

Validation Studies for the Dual Optimization of Indentation Creep and Stress Relaxation of Biological Soft Tissues Using Biphasic Poroviscoelasticity: Potential Method for Brain Tissue

2004 ◽  
Author(s):  
Joseph E. Olberding ◽  
Jun-Kyo Francis Suh
Keyword(s):  
Stress Relaxation ◽  
Brain Tissue ◽  
Material Properties ◽  
Computational Models ◽  
Soft Tissues ◽  
Optimization Technique ◽  
Biomechanical Testing ◽  
Potential Method ◽  
Indentation Creep ◽  
Creep And Stress Relaxation

Traumatic brain injury (TBI) is highly fatal and has profound physical and psychological repercussions for survivors. Knowledge of the precise material properties of brain tissue is crucial in developing holistic computational models to predict and prevent TBI. Despite the recent proliferation of material models of brain tissue, none have utilized porous media theory to explicitly include the significant fluid component of the hydrated soft tissue. Furthermore, the delicate composition of brain tissue limits the number of suitable biomechanical testing methodologies. In order to incorporate these considerations, in situ indentation creep and stress relaxation tests and linear biphasic poroviscoelasticity (BPVE) [1] were proposed to characterize the material properties of cerebral brain tissue. The objective of the present study was to evaluate these experimental and computational protocols in which the data from indentation creep and stress relaxation tests were simultaneously curve-fitted using a dual-optimization technique to determine the material parameters of the linear BPVE model.

Biomechanics Injury Analysis of Brain White Matter Using Cohesive Zone Method

2009 ◽  
Author(s):  
N. Abolfathi ◽  
A. R. Syed ◽  
G. Karami ◽  
M. Ziejewski
Keyword(s):  
White Matter ◽  
Brain Tissue ◽  
Cohesive Zone ◽  
Axonal Injury ◽  
Diffuse Axonal Injury ◽  
Severe Disabilities ◽  
Cohesive Zone Modeling ◽  
Zone Method ◽  
Brain White Matter ◽  
The Impact

Diffuse Axonal Injury (DAI) can happen due to sudden motion of the head and loading and is a major cause of fatality and severe disabilities. This injury can be biomechanically translated in terms of change in axon geometry and its separation and distortion from the surrounding cells and the extra cellular matrix (ECM). To study DAI, a microscale biomechanical modeling of tissue is forwarded. This modeling benefits from the studies on fibrous composite modeling procedure to examine the tissue and the fibrous axonal injury. Employing a developed micromechanics failure analysis for fibrous composites, the white mater of the brain is assumed as the composite with axon as the fiber and ECM as the matrix. The focus here is on the interface and adhesion of the axon and ECM on the material characteristics of the tissue. The cohesive zone modeling (CZM) is employed to model the interface. The impact due to interface is studied in detail on the characteristics of the white matter tissue. This modeling method enhances the previously proposed micromechanics modeling of brain tissue and enable one to predict the impact due to sliding, and separation of the axons and ECM on the load transfer, stress and strain distribution of axon, ECM and tissue for a microstructural examination of DAI and tissue failure. This can improve the understanding of injury from mechanical perspective and help in detail predicting of any injuries in cellular level in brain tissue.

Liquid Chromatography Analysis of Clozapine in Rat Brain Tissue, Using its Molecularly Imprinted Polymer after Administration of Toxic Dose of Drug and Lipid Emulsion Therapy

2019 ◽  
Vol 15 (3) ◽  
pp. 251-257
Author(s):  
Bahareh Sadat Yousefsani ◽  
Seyed Ahmad Mohajeri ◽  
Mohammad Moshiri ◽  
Hossein Hosseinzadeh
Keyword(s):  
Rat Brain ◽  
Brain Tissue ◽  
Molecularly Imprinted Polymer ◽  
Lipid Emulsion ◽  
Limit Of Detection ◽  
Imprinted Polymer ◽  
Toxic Dose ◽  
Molecularly Imprinted ◽  
The Brain ◽  
Rat Brain Tissue

Background:Molecularly imprinted polymers (MIPs) are synthetic polymers that have a selective site for a given analyte, or a group of structurally related compounds, that make them ideal polymers to be used in separation processes.Objective:An optimized molecularly imprinted polymer was selected and applied for selective extraction and analysis of clozapine in rat brain tissue.Methods:A molecularly imprinted solid-phase extraction (MISPE) method was developed for preconcentration and cleanup of clozapine in rat brain samples before HPLC-UV analysis. The extraction and analytical process was calibrated in the range of 0.025-100 ppm. Clozapine recovery in this MISPE process was calculated between 99.40 and 102.96%. The limit of detection (LOD) and the limit of quantification (LOQ) of the assay were 0.003 and 0.025 ppm, respectively. Intra-day precision values for clozapine concentrations of 0.125 and 0.025 ppm were 5.30 and 3.55%, whereas inter-day precision values of these concentrations were 9.23 and 6.15%, respectively. In this study, the effect of lipid emulsion infusion in reducing the brain concentration of drug was also evaluated.Results:The data indicated that calibrated method was successfully applied for the analysis of clozapine in the real rat brain samples after administration of a toxic dose to animal. Finally, the efficacy of lipid emulsion therapy in reducing the brain tissue concentration of clozapine after toxic administration of drug was determined.Conclusion:The proposed MISPE method could be applied in the extraction and preconcentration before HPLC-UV analysis of clozapine in rat brain tissue.

scholarly journals Evaluation of the impact of compliance of precast discs of overlapping on the work of the frame of a multi-storey building

2019 ◽  
Vol 97 ◽  
pp. 04022
Author(s):  
Nikolay Trekin ◽  
Emil Kodysh ◽  
Alexander Bybka ◽  
Alexander Yamalov ◽  
Nikita Konkov
Keyword(s):  
Economic Performance ◽  
Computational Models ◽  
Precast Concrete ◽  
Building Frames ◽  
Frame Building ◽  
Numerical Studies ◽  
Frame Buildings ◽  
The Impact ◽  
Structural Solutions ◽  
Storey Building

The article provides an analysis and justification of the need to take into account the compliance of discs of overlapping and coatings when calculating frames from precast concrete structures. Previously conducted full-scale experiments showed that the rigidity of the precast overlapping with full filling of the seams, in comparison with the monolithic overlapping, decreases by 3-15 times due to the ductility of the joints. The use of refined computational models of structural solutions for frames, which take into account the compliance of the conjugations of elements, makes it possible to trace possible redistribution of efforts. Such an approach when reconstructing, it is possible to optimally select and calculate the enforcement of structure, and on new designing, to increase reliability and / or improve the economic performance of frame buildings. According to the results of analytical studies, formulas were adopted for the parameters that allow one to take into account the overall compliance of overlapping disks and coatings in computational models of building frames. Numerical studies on the computational model of a frame building made it possible to evaluate the effect of accounting for compliance on the stress-strain state of a multi-storey frame.

scholarly journals The Biosynthesis of a Disialylganglioside by Galactosyltransferase from Rat Brain Tissue

1972 ◽  
Vol 247 (8) ◽  
pp. 2322-2327
Author(s):  
Frederico A. Cumar ◽  
John F. Tallman ◽  
Roscoe O. Brady
Keyword(s):  
Rat Brain ◽  
Brain Tissue ◽  
Rat Brain Tissue
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