INVESTIGATION OF THE CAVITATION AND PRESSURE CHANGE OF BRAIN TISSUE BASED ON A TRANSPARENT HEAD MODEL IN ITS DECELERATING IMPACT

2010 ◽  
Vol 10 (02) ◽  
pp. 361-372 ◽  
Author(s):  
SHENGXIONG LIU ◽  
ZHIYONG YIN ◽  
HUI ZHAO ◽  
GUANGYU YANG
Keyword(s):  
Brain Tissue ◽  
Normal Level ◽  
High Speed ◽  
Pressure Change ◽  
Positive Pressure ◽  
Head Model ◽  
Air Bubbles ◽  
Half Cycle ◽  
Air Bubble ◽  
The Brain

In this paper, a transparent physical head model with air bubbles to simulate the brain cavitation phenomena in head decelerating impact is presented. The transparent skull model was generated based on a real human skull through the turnover formwork technique, and a transparent gel was used to substitute the brain tissue. Air bubbles were created in the gel at the representative sites such as coup site and contrecoup site. After this, the head model was made to free fall from a position and impact on a fixed platform. The decelerating impacting process was recorded by a high-speed video camera and an accelerometer system. Through analyzing the video, the volume change of the air bubbles, namely, the mean pressure change of the air bubbles were calculated and compared. This new method has an advantage in investigating the brain cavitation phenomena using a direct and visual technique. The results showed explicitly and effectively that during the decelerating impact the contrecoup site air bubble was exposed mainly to a negative pressure which value became smaller and smaller in the first half of the impacting cycle and then came near to the normal level in the second half of the cycle; contrarily, the coup site air bubble was exposed mainly to a positive pressure which value became greater and greater in the first half of the impacting cycle and then came near to the normal level in the second half cycle. The probable biomechanics of the cavitation phenomenon is also given in this paper.

scholarly journals Effect of cannulation site on emboli travel during cardiac surgery

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Mira Puthettu ◽  
Stijn Vandenberghe ◽  
Stefanos Demertzis
Keyword(s):  
Cardiac Surgery ◽  
In Vitro Study ◽  
Blood Stream ◽  
Air Bubbles ◽  
Arterial Tree ◽  
Air Bubble ◽  
Cannulation Site ◽  
The Brain

Abstract Background During cardiac surgery, micro-air emboli regularly enter the blood stream and can cause cognitive impairment or stroke. It is not clearly understood whether the most threatening air emboli are generated by the heart-lung machine (HLM) or by the blood-air contact when opening the heart. We performed an in vitro study to assess, for the two sources, air emboli distribution in the arterial tree, especially in the brain region, during cardiac surgery with different cannulation sites. Methods A model of the arterial tree was 3D printed and included in a hydraulic circuit, divided such that flow going to the brain was separated from the rest of the circuit. Air micro-emboli were injected either in the HLM (“ECC Bubbles”) or in the mock left ventricle (“Heart Bubbles”) to simulate the two sources. Emboli distribution was measured with an ultrasonic bubble counter. Five repetitions were performed for each combination of injection site and cannulation site, where air bubble counts and volumes were recorded. Air bubbles were separated in three categories based on size. Results For both injection sites, it was possible to identify statistically significant differences between cannulation sites. For ECC Bubbles, axillary cannulation led to a higher amount of air bubbles in the brain with medium-sized bubbles. For Heart Bubbles, aortic cannulation showed a significantly bigger embolic load in the brain with large bubbles. Conclusions These preliminary in vitro findings showed that air embolic load in the brain may be dependent on the cannulation site, which deserves further in vivo exploration.

Fluid Drag Force Production and Motion Control of an Aquarobot Manipulator by Ejecting Air Bubbles

1990 ◽  
Vol 2 (5) ◽  
pp. 351-357
Author(s):  
Masakazu Ogasawara ◽  
◽  
Fumio Hara ◽  
Keyword(s):  
Drag Force ◽  
High Speed ◽  
Robot Manipulator ◽  
Force Production ◽  
Air Bubbles ◽  
Air Bubble ◽  
Fluid Forces ◽  
Fluid Drag ◽  
Force Reduction ◽  
Controlled Flow

The motion of a robot manipulator submerged in water is strongly affected by fluid forces, and it is an important technique to avoid their influence on the motion of an aquarobot manipulator to achieve high-speed, precise motion. This paper deals with extension of the technique of air bubble ejection from the manipulator surface, i.e., the mechanisms of reduction of drag force by air bubble ejection and its effects on the control of the aquarobot manipulator. Using a two-degree-of-freedom and two-joint manipulator, experiments were performed and the following major results were obtained: (1) There exists a particular pattern of air bubble ejection for reduction fluid drag force acting on the manipulator and it resulted in reduction of drag force by 25% compared to that for no air bubble ejection. (2) There exists a particular pattern of air bubble ejection that brought a 40% reduction of the control torque required for compensating the fluid drag force. (3) The major mechanisms for drag force reduction were found to be the controlled flow pattern around the manipulator formed by ejecting air bubbles. However, it is noted that these effects of air bubble ejection were dependent on the mode of manipulator motion.

A Novel Air Bubble Method to Compare the Pressure of the Brain Tissue in Head Decelerating Impact

2010 ◽  
Vol 36 (5) ◽  
pp. 5-14
Author(s):  
S.X. Liu ◽  
Z.Y. Yin ◽  
H. Zhao ◽  
G.Y. Yang
Keyword(s):  
Brain Tissue ◽  
Air Bubble ◽  
The Brain

The Research on Mechanism of Contre-Coup Injury in Brain Decelerating Impact Based on Trolley Experiment

2013 ◽  
Vol 394 ◽  
pp. 617-621
Author(s):  
Sheng Xiong Liu ◽  
Zhi Yong Yin ◽  
Zhong Min Chen ◽  
Sheng Ping Liu ◽  
Hui Zhao ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Negative Pressure ◽  
High Speed ◽  
Traffic Accidents ◽  
Head Model ◽  
High Speed Camera ◽  
Testing Method ◽  
Skull Model ◽  
The Impact

Based on the platform of trolley equipment, this paper used a liquid containing gas as a sensor to establish a new testing method in order to simulate the mechanism of contre-coup injury during head decelerating impact. After pouring the liquid containing gas into the transparent skull model, the head model was sealed and fixed to the trolley. Then the trolley was trigged to impact the counterguard as the speed of 50km/h, the impacting course was recorded by a high-speed camera at the same time. Finally, the movement of the gas in the liquid during the impact was analyzed using the sequence pictures analyzing software as to ensure the area of negative pressure which appeared during the impact. The results showed that in the head decelerating impact the negative pressure can appear at the contre-coup site. This denoted that in the traffic accidents brain tissue of driver or passengers may suffer from tension injury at the contre-coup point. This paper provides a new equipment and method to research the biomechanical mechanism of contre-coup injury in traffic accidents which is helpful to understand the distribution of negative pressure in brain tissue during head decelerating impact.

scholarly journals Study on Behind Helmet Blunt Trauma Caused by High-Speed Bullet

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhihua Cai ◽  
Xingyuan Huang ◽  
Yun Xia ◽  
Guibing Li ◽  
Zhuangqing Fan
Keyword(s):  
Brain Tissue ◽  
Blunt Trauma ◽  
Dura Mater ◽  
High Speed ◽  
Optimization Design ◽  
Reference Value ◽  
Element Model ◽  
Impact Speed ◽  
The Impact ◽  
The Brain

The mechanism of Behind Helmet Blunt Trauma (BHBT) caused by a high-speed bullet is difficult to understand. At present, there is still a lack of corresponding parameters and test methods to evaluate this damage effectively. The purpose of the current study is therefore to investigate the response of the human skull and brain tissue under the loading of a bullet impacting a bullet-proof helmet, with the effects of impact direction, impact speed, and impactor structure being considered. A human brain finite element model which can accurately reconstruct the anatomical structures of the scalp, skull, brain tissue, etc., and can realistically reflect the biomechanical response of the brain under high impact speed was employed in this study. The responses of Back Face Deformation (BFD), brain displacement, skull stress, and dura mater pressure were extracted from simulations as the parameters reflecting BHBT risk, and the relationships between BHBT and bullet-proof equipment structure and performance were also investigated. The simulation results show that the frontal impact of the skull produces the largest amount of BFD, and when the impact directions are from the side, the skull stress is about twice higher than other directions. As the impact velocity increases, BFD, brain displacement, skull stress, and dura mater pressure increase. The brain damage caused by different structural bullet bodies is different under the condition of the same kinetic energy. The skull stress caused by the handgun bullet is the largest. The findings indicate that when a bullet impacts on the bullet-proof helmet, it has a higher probability of causing brain displacement and intracranial high pressure. The research results can provide a reference value for helmet optimization design and antielasticity evaluation and provide the theoretical basis for protection and rescue.

A Photographic Study of the Effect of an Air Bubble on the Growth and Collapse of a Vapor Bubble Near a Surface

1972 ◽  
Vol 94 (4) ◽  
pp. 933-940 ◽  
Author(s):  
R. H. Smith ◽  
R. B. Mesler
Keyword(s):  
Vapor Bubble ◽  
High Speed ◽  
Room Temperature ◽  
Solid Boundary ◽  
High Speed Photography ◽  
Air Bubbles ◽  
Gas Bubble ◽  
Air Bubble ◽  
Spark Gap ◽  
Damage Prevention

Interaction of an individual vapor bubble formed by a spark gap in water at room temperature with a neighboring air bubble, such as could have significance in cavitation, was investigated using high speed photography. Air bubbles were located both on and far from boundaries. An air bubble located on the solid boundary was able to protect the surface from damage. Two effects of the interaction which appeared to be important in the damage prevention were energy transfer from the vapor bubble to the gas bubble and repulsion of the vapor bubble by the gas bubble. Gas bubbles far from boundaries absorbed less energy and had less repulsive effect than those on solid boundaries.

scholarly journals Inflow of oxygen and glucose in brain tissue induced by intravenous norepinephrine: relationships with central metabolic and peripheral vascular responses

2018 ◽  
Vol 119 (2) ◽  
pp. 499-508 ◽  
Author(s):  
R. Aaron Bola ◽  
Eugene A. Kiyatkin
Keyword(s):  
Brain Tissue ◽  
High Speed ◽  
Cardiac Activity ◽  
Sensory Nerves ◽  
Neural Activation ◽  
Glucose Levels ◽  
The Central Nervous System ◽  
Freely Moving ◽  
A Chain ◽  
The Brain

As an essential part of sympathetic activation that prepares the organism for “fight or flight,” peripheral norepinephrine (NE) plays an important role in regulating cardiac activity and the tone of blood vessels, increasing blood flow to the heart and the brain and decreasing blood flow to the organs not as necessary for immediate survival. To assess whether this effect is applicable to the brain, we used high-speed amperometry to measure the changes in nucleus accumbens (NAc) levels of oxygen and glucose induced by intravenous injections of NE in awake freely moving rats. We found that NE at low doses (2–18 μg/kg) induces correlative increases in NAc oxygen and glucose, suggesting local vasodilation and enhanced entry of these substances in brain tissue from the arterial blood. By using temperature recordings from the NAc, temporal muscle, and skin, we show that this central effect is associated with strong skin vasoconstriction and phasic increases in intrabrain heat production, indicative of metabolic neural activation. A tight direct correlation between NE-induced changes in metabolic activity and NAc levels of oxygen and glucose levels suggests that local cerebral vasodilation is triggered via a neurovascular coupling mechanism. Our data suggest that NE, by changing vascular tone and cardiac activity, triggers a visceral sensory signal that rapidly reaches the central nervous system via sensory nerves and induces neural activation. This neural activation leads to a chain of neurovascular events that promote entry of oxygen and glucose in brain tissue, thus preventing any possible metabolic deficit during functional activation. NEW & NOTEWORTHY Using high-speed amperometry and thermorecording in freely moving rats, we demonstrate that intravenous norepinephrine at physiological doses induces rapid correlative increases in nucleus accumbens oxygen and glucose levels coupled with increased intrabrain heat production. Although norepinephrine cannot cross the blood-brain barrier, by changing cardiac activity and vascular tone, it creates a sensory signal that reaches the central nervous system via sensory nerves, induces neural activation, and triggers a chain of neurovascular events that promotes intrabrain entry of oxygen and glucose.

Comparison of Brain Tissue Material Finite Element Models Based on Threshold for Traumatic Brain Injury

2016 ◽  
Author(s):  
Ashkan Eslaminejad ◽  
Hesam Sarvghad-Moghaddam ◽  
Asghar Rezaei ◽  
Mariusz Ziejewski ◽  
Ghodrat Karami
Keyword(s):  
Traumatic Brain Injury ◽  
Finite Element ◽  
Brain Injury ◽  
Dynamic Response ◽  
Brain Tissue ◽  
Head Model ◽  
Fe Modeling ◽  
Material Models ◽  
The Brain ◽  
Tissue Material

Blast traumatic brain injury (bTBI) may happen due to sudden blast and high-frequency loads. Due to the moral issues and the burden of experimental approaches, using computational methods such as finite element analysis (FEA) can be effective. Several finite element studies have focused on the effects of TBI to anticipate and understand the brain dynamic response. One of the most important factors in every FEA study of bTBI is the accurate modeling of brain tissue material properties. The main goal of this study is a comparison of different brain tissue constitutive models to understand the dynamic response of brain under an identical blast load. The multi-material FE modeling of the human head has several limitations such as its complexity and consequently high computational costs. Therefore, a spherical head model is modeled which suggests more straightforward observation/understanding of the FE modeling of skull (solid), CSF (fluid), and the brain tissue. Three different material models are considered for the brain tissue, namely hyperelastic, viscoelastic, and hyperviscoelastic. Brain dynamic responses are studied in terms of the head kinematics (linear acceleration), intracranial pressure (ICP), shear stress, and maximum mechanical strain. Our results showed that the hyperelastic model predicts larger ICP and shear than other constitutive brain tissue models. However, all material models predicted similar shear strain and head accelerations.

Experimental Study on Non-Exit Ballistic Induced Traumatic Brain Injury

2007 ◽  
Author(s):  
Jiangyue Zhang ◽  
Narayan Yoganandan ◽  
Frank A. Pintar ◽  
Yabo Guan ◽  
Thomas A. Gennarelli
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Brain Injuries ◽  
Gunshot Wounds ◽  
Pressure Change ◽  
Frame Rate ◽  
Cranial Bone ◽  
Head Model ◽  
Injury Biomechanics ◽  
The Brain

Ballistic-induced traumatic brain injury remains the most severe type of injury with the highest rate of fatality. Yet, its injury biomechanics remains the least understood. Ballistic injury biomechanics studies have been mostly focused on the trunk and extremities using large gelatin blocks with unconstrained boundaries [1, 2]. Results from these investigations are not directly applicable to brain injuries studies because the human head is smaller and the soft brain is enclosed in a relatively rigid cranium. Thali et al. developed a “skin-skull-brain” model to reproduce gunshot wounds to the head for forensic purposes [3]. These studies focused on wound morphology to the skull rather than brain injury. Watkins et al. used human dry skulls filled with gelatin and investigated temporary cavities and pressure change [4]. However, the frame rate of the cine X-ray was too slow to describe the cavity dynamics, and pressures were only quantified at the center of skull. In addition, the ordnance gelatin used in these studies is not the most suitable simulant to model brain material because of differences in dynamic moduli [5]. Sylgard gel (Dow Corning Co., Midland, MI) demonstrates similar behavior as the brain and has been used as a brain surrogate to determine brain deformations under blunt impact loading [6, 7]. Zhang et al. used the simulant for ballistic brain injury and investigated the correlation between temporary cavity pulsation and pressure change [8, 9]. However, the skulls used in these models were not as rigid as the human cranium. The presence of a stronger cranial bone may significantly decrease the projectile velocity and change the kinematics of cavity and pressure distribution in the cranium. In addition, projectiles perforated through the models in these studies. Patients with through-and-through perforating gunshot wounds to the head have a greater fatality rate than patients with non-exit penetrating wounds [10]. Therefore, it is more clinically relevant to investigate non-exit ballistic traumatic brain injuries. Consequently, the current study is designed to investigate the brain injury biomechanics from non-exit penetrating projectile using an appropriately sized and shaped physical head model.

BIOMECHANICAL ANALYSIS OF OCCUPANT’S BRAIN RESPONSE AND INJURY IN VEHICLE INTERIOR SECOND IMPACT UTILIZING A REFINED HEAD FINITE ELEMENT MODEL

2017 ◽  
Vol 17 (07) ◽  
pp. 1740018
Author(s):  
ZHENGWEI MA ◽  
LELE JING ◽  
JINLUN WANG ◽  
JIQING CHEN ◽  
FENGCHONG LAN
Keyword(s):  
Finite Element ◽  
Brain Injury ◽  
Side Impact ◽  
Positive Pressure ◽  
Head Model ◽  
Vertical Angle ◽  
Extreme Stress ◽  
Horizontal Angle ◽  
The Impact ◽  
The Brain

In vehicle side collisions, traumatic brain injury caused by the impact between occupant’s head and the interior parts of A or B pillar is a major reason of death and disability. In order to analyze the biomechanical response and injury mechanism of occupant’s brain in side collisions, a refined finite element head model representing the 50th percentile Chinese male was developed. Its improvements of biofidelity comparing to the original head model were illustrated through model simulation against the same post mortem human subjects test. Based on the refined head model, the brain biomechanical responses and injuries in the side impact with interior parts of A pillar and B pillar were analyzed according to FMVSS 201U, and the influences of different impact locations and directions were investigated. The results showed that the brain tissues on impact side sustained positive pressure and those on the opposite side experienced negative pressure. The transmission of pressure wave was easy to cause brain concussion and other diffuse brain injuries. The intracranial pressure distribution exhibited a typical pattern of contrecoup injury. The extreme stress concentration in the junction area of the cerebrum, cerebellum and brain stem could lead to focal injury such as brain contusion and laceration. Moreover, the impact injury of A pillar was more serious than that of B pillar, which was consistent with the traffic injury statistics that the head injury in oblique side collisions was more serious than that of vertical side collisions. Therefore, the interior parts of A pillar should be designed to absorb more energy than those of B pillar under the same conditions. In addition, the severity of brain injury is more sensitive to the variation of the horizontal angle than that of the vertical angle. Both the peak values of the occipital fossa pressure in effect simulations of the horizontal and vertical angles were three to four times of the peak values of the forehead pressure. When the impact horizontal angle was up to 255[Formula: see text], or the vertical angle was up to 45[Formula: see text], the head HIC(d) values would be up to 1320.45 and 1101.06, respectively, which indicated a AIS 3[Formula: see text] injury risk of the head.

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