scholarly journals Mechanism of Coup and Contrecoup Injuries Induced by a Knock-Out Punch

2020 ◽  
Vol 25 (2) ◽  
pp. 22 ◽  
Author(s):  
Milan Toma ◽  
Rosalyn Chan-Akeley ◽  
Christopher Lipari ◽  
Sheng-Han Kuo
Keyword(s):  
Cerebrospinal Fluid ◽  
Interaction Model ◽  
Brain Parenchyma ◽  
Primary Objective ◽  
Element Analysis ◽  
Knock Out ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact ◽  
The Brain

Primary Objective: The interaction of cerebrospinal fluid with the brain parenchyma in an impact scenario is studied. Research Design: A computational fluid-structure interaction model is used to simulate the interaction of cerebrospinal fluid with a comprehensive brain model. Methods and Procedures: The method of smoothed particle hydrodynamics is used to simulate the fluid flow, induced by the impact, simultaneously with finite element analysis to solve the large deformations in the brain model. Main Outcomes and Results: Mechanism of injury resulting in concussion is demonstrated. The locations with the highest stress values on the brain parenchyma are shown. Conclusions: Our simulations found that the damage to the brain resulting from the contrecoup injury is more severe than that resulting from the coup injury. Additionally, we show that the contrecoup injury does not always appear on the side opposite from where impact occurs.

Cerebrospinal Fluid Interaction with Cerebral Cortex during Pediatric Abusive Head Trauma

2020 ◽  
Vol 18 (05) ◽  
pp. 223-230 ◽  
Author(s):  
Milan Toma ◽  
Alfonso Dehesa-Baeza ◽  
Rosalyn Chan-Akaley ◽  
Paul D. H. Nguyen ◽  
Hallie Zwibel
Keyword(s):  
Cerebrospinal Fluid ◽  
Head Trauma ◽  
Brain Injuries ◽  
Abusive Head Trauma ◽  
Severe Form ◽  
Long Term Effects ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Brain

AbstractAbusive head trauma is the leading cause of fatal brain injuries in children younger than 2 years. It is a preventable and severe form of physical child abuse often linked to the forceful shaking of an infant or toddler. Victims of abusive head trauma can suffer permanent neurological damage, resulting in developmental delay and disability. The long-term effects of abusive head trauma are difficult to diagnose and predict. In this model, we use a high-order finite element method paired with the most comprehensive and current head/brain model and next-generation smoothed particle hydrodynamics. This is one of the first fluid–structure interaction frameworks that uses fluid material properties to represent the cerebrospinal fluid (CSF) while including all major anatomical features of the brain. The interaction of CSF with the brain cortex during abusive head trauma is demonstrated during multiple shaking cycles. A comprehensive and precise model that calculates for the role of CSF in neurological trauma will be useful both in the prevention and treatment of abusive head trauma and the determination of prognosis and patient outcomes.

scholarly journals Numerical Simulation of Non-Homogeneous Viscous Debris-Flows Based on the Smoothed Particle Hydrodynamics (SPH) Method

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2314 ◽  
Author(s):  
Shu Wang ◽  
Anping Shu ◽  
Matteo Rubinato ◽  
Mengyao Wang ◽  
Jiping Qin
Keyword(s):  
Debris Flow ◽  
Water Content ◽  
Smoothed Particle Hydrodynamics ◽  
Debris Flows ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
The Impact ◽  
Kinetic And Potential Energies

Non-homogeneous viscous debris flows are characterized by high density, impact force and destructiveness, and the complexity of the materials they are made of. This has always made these flows challenging to simulate numerically, and to reproduce experimentally debris flow processes. In this study, the formation-movement process of non-homogeneous debris flow under three different soil configurations was simulated numerically by modifying the formulation of collision, friction, and yield stresses for the existing Smoothed Particle Hydrodynamics (SPH) method. The results obtained by applying this modification to the SPH model clearly demonstrated that the configuration where fine and coarse particles are fully mixed, with no specific layering, produces more fluctuations and instability of the debris flow. The kinetic and potential energies of the fluctuating particles calculated for each scenario have been shown to be affected by the water content by focusing on small local areas. Therefore, this study provides a better understanding and new insights regarding intermittent debris flows, and explains the impact of the water content on their formation and movement processes.

Sensitivity Analysis of Smoothed Particle Hydrodynamics in PAM-CRASH for Modeling of Soft Soils

2013 ◽  
Author(s):  
Ranvir Dhillon ◽  
Moustafa El-Gindy ◽  
Rustam Ali ◽  
David Philipps ◽  
Fredrik Öijer ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Soft Soil ◽  
Strength Criterion ◽  
Model Parameters ◽  
Rapid Progression ◽  
Element Analysis ◽  
Particle Modeling ◽  
Modeling Techniques ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

The rapid progression of computational power and development of non-mesh particle modeling techniques provides solutions to problems which are not accurately modeled using traditional finite element analysis techniques. The field of soft soil modeling has been pressing on in recent years and the smoothed particle hydrodynamics (SPH) modeling method in PAM-CRASH provides opportunity for further advancement in accuracy. This research focuses on the development of soft soil models using SPH with verification using pressure-sinkage and shear strength criterion. Soil model parameters such as geometry and contact model are varied to determine the effect of the parameters on the behaviour of the soft soil and relationships are developed. The developed virtual soil models are compared against existing soils to determine which soils are accurately modeled and further refinements are made to validate the models with existing empirical data.

scholarly journals The Potential Roles of Blood–Brain Barrier and Blood–Cerebrospinal Fluid Barrier in Maintaining Brain Manganese Homeostasis

Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1833
Author(s):  
Shannon Morgan McCabe ◽  
Ningning Zhao
Keyword(s):  
Cerebrospinal Fluid ◽  
Blood Brain Barrier ◽  
Blood Circulation ◽  
Critical Role ◽  
Systemic Circulation ◽  
Brain Parenchyma ◽  
Brain Barrier ◽  
Blood Brain ◽  
The Brain

Manganese (Mn) is a trace nutrient necessary for life but becomes neurotoxic at high concentrations in the brain. The brain is a “privileged” organ that is separated from systemic blood circulation mainly by two barriers. Endothelial cells within the brain form tight junctions and act as the blood–brain barrier (BBB), which physically separates circulating blood from the brain parenchyma. Between the blood and the cerebrospinal fluid (CSF) is the choroid plexus (CP), which is a tissue that acts as the blood–CSF barrier (BCB). Pharmaceuticals, proteins, and metals in the systemic circulation are unable to reach the brain and spinal cord unless transported through either of the two brain barriers. The BBB and the BCB consist of tightly connected cells that fulfill the critical role of neuroprotection and control the exchange of materials between the brain environment and blood circulation. Many recent publications provide insights into Mn transport in vivo or in cell models. In this review, we will focus on the current research regarding Mn metabolism in the brain and discuss the potential roles of the BBB and BCB in maintaining brain Mn homeostasis.

scholarly journals Impact and Fire Modeling Considerations Employing SPH Coupling to a Dilute Spray Fire Code

2009 ◽  
Author(s):  
Alexander L. Brown
Keyword(s):  
High Speed ◽  
Good Method ◽  
Predictive Tool ◽  
Surface Deposition ◽  
Impact Surface ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Model Inadequacy ◽  
The Impact ◽  
Adequate Method

Transportation accidents and the subsequent fire present a concern. Particularly energetic accidents like an aircraft impact or a high speed highway accident can be quite violent. We would like to develop and maintain a capability at Sandia National Laboratories to model these very challenging events. We have identified Smoothed Particle Hydrodynamics (SPH) as a good method to employ for the impact dynamics of the fluid for severe impacts. SPH is capable of modeling viscous and inertial effects for these impacts for short times. We have also identified our fire code Lagrangian/Eulerian (L/E) particle capability as an adequate method for fuel transport and spray modeling. A fire code can also model the subsequent fire for a fuel impact. Surface deposition of the liquid may also be acceptably predicted with the same code. These two methods (SPH and L/E) typically employ complimentary length and timescales for the calculation, and are potentially suited for coupling given adequate attention to relevant details. Length and timescale interactions are important considerations when joining the two capabilities. Additionally, there are physical model inadequacy considerations that contribute to the accuracy of the methodology. These models and methods are presented and evaluated. Some of these concerns are detailed for a verification type scenario used to show the work in progress of this coupling capability. The importance of validation methods and their appropriate application to the genesis of this class of predictive tool are also discussed.

Modeling Hypervelocity Impacts Using Smoothed Particle Hydrodynamics

2018 ◽  
Author(s):  
M. Ganser ◽  
B. van der Linden ◽  
C. G. Giannopapa
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Large Deformations ◽  
Hypervelocity Impact ◽  
Density Fluctuations ◽  
Computational Domain ◽  
Simulation Tool ◽  
Hypervelocity Impacts ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

Hypervelocity impacts occur in outer space where debris and micrometeorites with a velocity of 2 km/s endanger spacecraft and satellites. A proper shield design, e.g. a laminated structure, is necessary to increase the protection capabilities. High velocities result in massive damages. The resulting large deformations can hardly be tackled with mesh based discretization methods. Smoothed Particle Hydrodynamics (SPH), a Lagrangian meshless scheme, can resolve large topological changes whereas it still follows the continuous formulation. Derived by variational principles, SPH is able to capture large density fluctuations associated with hypervelocity impacts correctly. Although the impact region is locally limited, a much bigger domain has to be discretized because of strong outgoing pressure waves. A truncation of the computational domain is preferable to save computational power, but this leads to artificial reflections which influence the real physics. In this paper, hypervelocity impact (HVI) is modelled by means of basic conservation assumptions leading to the Euler equations of fluid dynamics accompanied by the Mie-Grueneisen equation of state. The newly developed simulation tool SPHlab presented in this work utilizes the discretization method smoothed particle hydrodynamics (SPH) to capture large deformations. The model is validated through a number of test cases. Different approaches are presented for non-reflecting boundaries in order to tackle artificial reflections on a computational truncated domain. To simulate an HVI, the leading continuous equations are derived and the simulation tool SPHlab is developed. The method of characteristics allows to define proper boundary fluxes by removing the inwards travelling information. One- and two-dimensional model problems are examined which show excellent absorption behaviour. An hypervelocity impact into a laminated shield is simulated and analysed and a simple damage model is introduced to model a spallation failure mode.

scholarly journals Application of Smoothed Particle Hydrodynamics (SPH) for the Simulation of Flow-like Landslides on 3D Terrains

2022 ◽  
Author(s):  
Binghui Cui ◽  
Liaojun Zhang
Keyword(s):  
Risk Assessment ◽  
Smoothed Particle Hydrodynamics ◽  
Disaster Mitigation ◽  
Sph Method ◽  
Landslide Event ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Simulation Results ◽  
Mitigation Design ◽  
The Impact

Abstract Flow-type landslide is one type of landslide that generally exhibits characteristics of high flow velocities, long jump distances, and poor predictability. Simulation of it facilitates propagation analysis and provides solutions for risk assessment and mitigation design. The smoothed particle hydrodynamics (SPH) method has been successfully applied to the simulation of two-dimensional (2D) and three-dimensional (3D) flow-like landslides. However, the influence of boundary resistance on the whole process of landslide failure is rarely discussed. In this study, a boundary algorithm considering the friction is proposed, and integrated into the boundary condition of the SPH method, and its accuracy is verified. Moreover, the Navier-Stokes equation combined with the non-Newtonian fluid rheology model was utilized to solve the dynamic behavior of the flow-like landslide. To verify its performance, the Shuicheng landslide event, which occurred in Guizhou, China, was taken as a case study. In the 2D simulation, a sensitivity analysis was conducted, and the results showed that the shearing strength parameters have more influence on the computation accuracy in comparison with the coefficient of viscosity. Afterwards, the dynamic characteristics of the landslide, such as the velocity and the impact area, were analyzed in the 3D simulation. The simulation results are in good agreement with the field investigations. The simulation results demonstrate that the SPH method performs well in reproducing the landslide process, and facilitates the analysis of landslide characteristics as well as the affected areas, which provides a scientific basis for conducting the risk assessment and disaster mitigation design.

scholarly journals Microglia motility depends on neuronal activity and promotes structural plasticity in the hippocampus

2019 ◽  
Author(s):  
Felix C. Nebeling ◽  
Stefanie Poll ◽  
Lena C. Schmid ◽  
Manuel Mittag ◽  
Julia Steffen ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Dendritic Spines ◽  
Synapse Formation ◽  
Brain Parenchyma ◽  
Two Photon ◽  
Contact Rates ◽  
Health And Disease ◽  
The Impact ◽  
The Brain

AbstractMicroglia, the resident immune cells of the brain, play a complex role in health and disease. They actively survey the brain parenchyma by physically interacting with other cells and structurally shaping the brain. Yet, the mechanisms underlying microglia motility and their significance for synapse stability, especially during adulthood, remain widely unresolved. Here we investigated the impact of neuronal activity on microglia motility and its implication for synapse formation and survival. We used repetitive two-photon in vivo imaging in the hippocampus of awake mice to simultaneously study microglia motility and their interaction with synapses. We found that microglia process motility depended on neuronal activity. Simultaneously, more dendritic spines emerged in awake compared to anesthetized mice. Interestingly, microglia contact rates with individual dendritic spines were associated with their stability. These results suggest that microglia are not only sensing neuronal activity, but participate in synaptic rewiring of the hippocampus during adulthood, which has profound relevance for learning and memory processes.

Cranioplasty Reverses Dysfunction of the Solutes Distribution in the Brain Parenchyma After Decompressive Craniectomy

Neurosurgery ◽  
2020 ◽  
Vol 87 (5) ◽  
pp. 1064-1069 ◽  
Author(s):  
Alin Borha ◽  
Audrey Chagnot ◽  
Romain Goulay ◽  
Evelyne Emery ◽  
Denis Vivien ◽  
...  
Keyword(s):  
Decompressive Craniectomy ◽  
Early Time ◽  
Brain Parenchyma ◽  
Late Time ◽  
Perivascular Spaces ◽  
Early Time Point ◽  
The Impact ◽  
The Brain ◽  
Brain Homeostasis ◽  
Time Point

Abstract Background Solutes distribution by the intracranial cerebrospinal fluid (CSF) fluxes along perivascular spaces and through interstitial fluid (ISF) play a key role in the clearance of brain metabolites, with essential functions in maintaining brain homeostasis. Objective To investigate the impact of decompressive craniectomy (DC) and cranioplasty (CP) on the efficacy of solutes distribution by the intracranial CSF and ISF flux. Methods Mice were allocated in 3 groups: sham surgery, DC, and DC followed by CP. The solutes distribution in the brain parenchyma was assessed using T1 magnetic resonance imaging after injection of DOTA-Gadolinium in the cisterna magna. This evaluation was performed at an early time point following DC (after 2 d) and at a later time point (after 15 d). We evaluated the solutes distribution in the whole brain and in the region underneath the DC area. Results Our results demonstrate that the global solutes distribution in the brain parenchyma is impaired after DC in mice, both at early and late time-points. However, there was no impact of DC on the solutes distribution just under the craniectomy. We then provide evidence that this impairment was reversed by CP. Conclusion The solute distribution in the brain parenchyma by the CSF and ISF is impaired by DC, a phenomenon reversed by CP.

Numerical Simulations of Regular Wave Impact on Horizontal Plate Based on SPH Methods

2013 ◽  
Vol 353-356 ◽  
pp. 3531-3536
Author(s):  
Kun Zheng ◽  
Zhao Chen Sun ◽  
Chang Ping Chen ◽  
Feng Zhou
Keyword(s):  
Estimation Method ◽  
Impact Pressure ◽  
Horizontal Plate ◽  
Regular Waves ◽  
Wave Impact ◽  
Numerical Wave Flume ◽  
Wave Flume ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
The Impact

The numerical wave flume was established for simulating the impact effects of regular waves on horizontal plate by adopting the method of Smoothed Particle Hydrodynamics (SPH).The impact process of regular waves on horizontal plate was analyzed, and the impact pressure-time curves were gotten using a new estimation method. The comparison of numerical results and experimental results shows that the new estimation method can predict the peak impact pressure more accurately.

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