scholarly journals Computation of history-dependent mechanical damage of axonal fiber tracts in the brain: towards tracking sub-concussive and occupational damage to the brain

2018 ◽  
Author(s):  
Jesse I. Gerber ◽  
Harsha T. Garimella ◽  
Reuben H. Kraft
Keyword(s):  
Fiber Bundle ◽  
Brain Injuries ◽  
Mechanical Response ◽  
Head Injuries ◽  
Mechanical Damage ◽  
Tissue Level ◽  
Internal Damage ◽  
Damage Models ◽  
Axonal Fiber ◽  
The Brain

ABSTRACTFinite element models are frequently used to simulate traumatic brain injuries. However, current models are unable to capture the progressive damage caused by repeated head trauma. In this work, we propose a method for computing the history-dependent mechanical damage of axonal fiber bundle tracts in the brain. Through the introduction of multiple damage models, we provide the ability to link consecutive head impact simulations, so that potential injury to the brain can be tracked over time. In addition, internal damage variables are used to degrade the mechanical response of each axonal fiber bundle element. As a result, the stiffness of the aggregate tissue decreases as damage evolves. To counteract this degenerative process, we have also introduced a preliminary healing model that reverses the accumulated damage, based on a user-specified healing duration. Using two detailed examples, we demonstrate that damage produces a significant decrease in fiber stress, which ultimately propagates to the tissue level and produces a measurable decrease in overall stiffness. These results suggest that damage modeling has the potential to enhance current brain simulation techniques and lead to new insights, especially in the study of repetitive head injuries.

scholarly journals Mitigating the Consequences of Subconcussive Head Injuries

2020 ◽  
Vol 22 (1) ◽  
pp. 387-407
Author(s):  
Eric A. Nauman ◽  
Thomas M. Talavage ◽  
Paul S. Auerbach
Keyword(s):  
Head Injury ◽  
Clinical Diagnosis ◽  
Head Injuries ◽  
Tissue Level ◽  
Clinical Neurology ◽  
Subconcussive Injury ◽  
History Of ◽  
Tissue Alteration ◽  
The Brain

Subconcussive head injury represents a pathophysiology that spans the expertise of both clinical neurology and biomechanical engineering. From both viewpoints, the terms injury and damage, presented without qualifiers, are synonymously taken to mean a tissue alteration that may be recoverable. For clinicians, concussion is evolving from a purely clinical diagnosis to one that requires objective measurement, to be achieved by biomedical engineers. Subconcussive injury is defined as subclinical pathophysiology in which underlying cellular- or tissue-level damage (here, to the brain) is not severe enough to present readily observable symptoms. Our concern is not whether an individual has a (clinically diagnosed) concussion, but rather, how much accumulative damage an individual can tolerate before they will experience long-term deficit(s) in neurological health. This concern leads us to look for the history of damage-inducing events, while evaluating multiple approaches for avoiding injury through reduction or prevention of the associated mechanically induced damage.

The Effects of Directionality of Blunt Impacts on Mechanical Response of the Brain

2014 ◽  
Author(s):  
Hesam Sarvghad-Moghaddam ◽  
Ghodrat Karami ◽  
Mariusz Ziejewski
Keyword(s):  
Shear Stress ◽  
Mechanical Response ◽  
Diffuse Axonal Injury ◽  
Linear Acceleration ◽  
Human Head ◽  
Tissue Level ◽  
Injury Criteria ◽  
Local Shear ◽  
The Brain ◽  
Local Shear Stress

The intrinsic complexity of the human head and brain lies within the non-uniformity of their constitutive components in terms of shape, material, function, and tolerance. Due to this complexity, the directionality of impact, when the head is exposed to an assault, is a major concern as different responses are anticipated based on the location of impact. The main objective of the study was to show that while most studies propose the injury criteria as based on the kinematical parameters, the tissue-level brain features are more substantiated injury indicators. Accordingly, a finite element (FE) approach was employed to elucidate the injury-related behavior of the head for front, back, and side impacts against a rigid wall. To this end, a 50th percentile FE head-neck model, including most anatomical features, was used. The kinematics of the head in terms of the linear acceleration, as well as the biomechanical response of the brain at the tissue level in terms of intracranial pressure (ICP) and maximum local shear stress, were evaluated as the main injury criteria. Ls-Dyna, a transient, nonlinear, and explicit FE code, was employed to carry out all the simulations. To verify the influence of impact directionality, identical boundary conditions were enforced in all impact scenarios. While brain responses showed similar patterns in all three directions, different peak values were predicted. The highest peak values for the local shear stress, ICP gradient, and the center mass linear acceleration of brain were observed for the frontal impact. These threshold values are of great significance in predicting injuries such as diffuse axonal injury (DAI) resulting from the shear deformation of brain axons. It is believed that directionality considerations could greatly help to improve the design of protective headgears which are considered to be the most effective tools in mitigating a TBI.

Methyl jasmonate delays the latency to anoxic convulsions by normalizing the brain levels of oxidative stress biomarkers and serum corticosterone contents in mice with repeated anoxic stress

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Abayomi Ololade Adelaja ◽  
Oluwafemi Gabriel Oluwole ◽  
Oritoke Modupe. Aluko ◽  
Solomon Umukoro
Keyword(s):  
Oxidative Stress ◽  
Blood Glucose ◽  
Methyl Jasmonate ◽  
Brain Injuries ◽  
Antioxidant Property ◽  
Oxidative Stress Biomarkers ◽  
Serum Corticosterone ◽  
Stress Agent ◽  
Cellular Antioxidants ◽  
The Brain

AbstractObjectivesRepeated exposure to anoxic stress damages the brain through cortisol-mediated increases in oxidative stress and cellular-antioxidants depletion. Thus, compounds with antioxidant property might confer protection against anoxic stress-induced brain injuries. In this study, we further examined the protective effect of methyl jasmonate (MJ), a potent anti-stress agent against anoxic stress-induced convulsions in mice.MethodsThirty-six male Swiss mice randomized into six groups (n=6) were given MJ (25, 50 and 100 mg/kg, i.p.) or vehicle (10 mL/kg, i.p.) 30 min before 15 min daily exposure to anoxic stress for 7 days. The latency(s) to anoxic convulsion was recorded on day 7. The blood glucose and serum corticosterone levels were measured afterwards. The brains were also processed for the determination of malondialdehyde, nitrite, and glutathione levels.ResultsMethyl jasmonate (MJ) delayed the latency to anoxic convulsion and reduced the blood glucose and serum corticosterone levels. The increased malondialdehyde and nitrite contents accompanied by decreased glutathione concentrations in mice with anoxic stress were significantly attenuated by MJ.ConclusionsThese findings further showed that MJ possesses anti-stress property via mechanisms relating to the reduction of serum contents of corticosterone and normalization of brain biomarker levels of oxidative stress in mice with anoxic stress.

scholarly journals Structural brain injury in sports-related concussion

2012 ◽  
Vol 33 (6) ◽  
pp. E6 ◽  
Author(s):  
Scott L. Zuckerman ◽  
Andrew Kuhn ◽  
Michael C. Dewan ◽  
Peter J. Morone ◽  
Jonathan A. Forbes ◽  
...  
Keyword(s):  
Brain Injury ◽  
Literature Review ◽  
Brain Injuries ◽  
Case Reports ◽  
Head Injuries ◽  
Health Concern ◽  
Prevalence Data ◽  
Small Series ◽  
Structural Brain

Object Sports-related concussions (SRCs) represent a significant and growing public health concern. The vast majority of SRCs produce mild symptoms that resolve within 1–2 weeks and are not associated with imaging-documented changes. On occasion, however, structural brain injury occurs, and neurosurgical management and intervention is appropriate. Methods A literature review was performed to address the epidemiology of SRC with a targeted focus on structural brain injury in the last half decade. MEDLINE and PubMed databases were searched to identify all studies pertaining to structural head injury in sports-related head injuries. Results The literature review yielded a variety of case reports, several small series, and no prospective cohort studies. Conclusions The authors conclude that reliable incidence and prevalence data related to structural brain injuries in SRC cannot be offered at present. A prospective registry collecting incidence, management, and follow-up data after structural brain injuries in the setting of SRC would be of great benefit to the neurosurgical community.

scholarly journals Evaluation of Common Concussion Tools Used in a Sport’s Setting

2021 ◽  
Vol 18 ◽  
pp. 24-31
Author(s):  
Brady Armitage ◽  
B. Sue Graves
Keyword(s):  
Sports Medicine ◽  
Diagnostic Procedure ◽  
Brain Injuries ◽  
Traumatic Brain Injuries ◽  
Diagnostic Tools ◽  
Mechanism Of Injury ◽  
Mild Traumatic Brain Injuries ◽  
The Brain

Sports medicine advancements are continuously evolving allowing professionals to utilize tools to provide for their athletes’ care. These tools have allowed clinicians to better diagnose and determine the extent of an athlete’s injury. Over the last 20 years, an emphasis has been placed on mild traumatic brain injuries (mTBI) and/or concussions. This focus on mTBI and concussions has led to an understanding of the mechanism of injury (MOI), development of grading/severity scales of injury, and diagnostic tools for properly assessing an athlete suffering from an injury to the brain. Clinicians understanding of concussion has excelled in recent years, but with advancement in technologies and diagnostic tools, all professionals need to understand the importance of incorporating tools into the diagnostic procedure. Thus, the purpose of this review is to evaluate common tools in practice, as well as newer tools, that could be utilized by sports medicine professionals.

scholarly journals The Frey Effect of Microwave Sonic Weapons

2018 ◽  
Vol 1 (2) ◽  
pp. 01-04
Author(s):  
Robert Skopec
Keyword(s):  
Brain Injuries ◽  
State Department ◽  
Health Issues ◽  
Government Employees ◽  
The Brain ◽  
The U.S

State Department evacuates a number of Americans from the U.S. consulate in Guangzhou, China after they experienced unexplained health issues. A group of U.S. diplomats stationed in China have been brought back to the states after being inflicted by a mystery illness that reportedly resembles the brain injuries previously suffered by staff in Cuba. Heather Nauert, a State Department spokeswoman, said in a statement that the individuals from the U.S. office in Guangzhou were returned home for further evaluation. It was unclear if there was any connection to last year’s situation in Cuba where 24 U.S. government employees experienced a range of ailments after hearing an unusual sound.

scholarly journals New cerebrovascular agent with hypotensive activity

2019 ◽  
Vol 5 (2) ◽  
pp. 71-77
Author(s):  
Galina A. Kim ◽  
Tamara S. Gan’shina ◽  
Elena V. Kurza ◽  
Ilya N. Kurdyumov ◽  
Denis V. Maslennikov ◽  
...  
Keyword(s):  
Blood Flow ◽  
Antihypertensive Agent ◽  
Brain Injuries ◽  
Cerebrovascular Disorders ◽  
Male Rats ◽  
Hypotensive Activity ◽  
Duration Of Action ◽  
Ischemic Brain ◽  
Cerebrovascular Activity ◽  
The Brain

Introduction: In cerebrovascular disorders, special attention is paid to a hypertensive cerebrovascular crisis, which combines a vascular injury of the brain and hypertension. The paper studies the cerebrovascular properties of the calcium channel blocker of S-Amlodipine nicotinate antihypertensive agent. Materials and methods: Tests were performed on 96 nonlinear male rats, measuring local blood flow in the cerebral cortex in 36 awake animals, using a laser Doppler flowmeter. Cerebral circulation was recorded in the animals when modeling ischemic and hemorrhagic brain injuries. Results and discussion: S-Amlodipine nicotinate (0.1 mg/kg i/v) shows a pronounced cerebrovascular activity in the models of ischemic and hemorrhagic injuries of the brain. In terms of the vasodilating effect in ischemic brain injury, the drug is comparable to mexidol, nimodipine, picamilon, but is superior to nimodipine and picamilon in terms of duration of action, and in the model of hemorrhagic stroke, S-Amlodipine nicotinate is superior to nimodipine and is comparable to picamilon and mexidol. The analysis of the mechanism of action of the agent revealed the participation of GABA A-receptors in the implementation of cerebrovascular properties of the agent. Conclusion: Significant cerebrovascular activity of S-Amlodipine nicotinate (0.1 mg/kg i/v) antihypertensive agent was revealed. The presence of GABAergic mechanism on cerebral blood flow in the agent action along with blockade of slow calcium channels ensures its high efficacy in treatment of both ischemic and hemorrhagic brain injuries.

scholarly journals Anisotropic Mechanical Response and Strain Localization of a Metallic Glassy-Fiber-Reinforced Polyethylene Terephthalate Fabric

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5619
Author(s):  
Jie Li ◽  
Bo Huang ◽  
Jun Shen ◽  
Jun Yi ◽  
Yandong Jia ◽  
...  
Keyword(s):  
Polyethylene Terephthalate ◽  
Strain Localization ◽  
Fiber Bundle ◽  
Mechanical Response ◽  
Materials Science ◽  
Image Correlation ◽  
Woven Fabric ◽  
Dominant Factor ◽  
Fracture Mechanisms ◽  
Young’S Moduli

Optimizing the mechanical properties of composites through microstructural design has been a long-standing issue in materials science. In this study, we reinforced a typical polymer, i.e., polyethylene-terephthalate-woven fabric, with a type of Fe-based metallic glassy fiber (MGF) with an extremely large Young’s moduli. The MGF-reinforced fabrics, with three different fiber bundle orientations (0°, 45°, and 90°), were investigated by in situ electron-microscopy mechanical testing techniques in conjunction with a digital image correlation (DIC) technique. The fabrics exhibited a pronounced anisotropic mechanical response, and the associated characteristics were verified to depend on the fiber bundle orientation relative to the external load. Furthermore, localized strains near the intersections of the fiber bundles were found to be much higher than the global strain. It is confirmed that the restriction from warp to weft is the dominant factor influencing strain localization during deformation. Our results are enlightening for understanding the fracture mechanisms of composites.

scholarly journals COMPLEX FORENSIC MEDICAL EVALUATION OF THE TRAUMATIC BRAIN INJURY: CASE OF PRACTICE

2021 ◽  
Vol 121 (1) ◽  
pp. 65-69
Author(s):  
Svіtlana Diachenko ◽  
Roksolana Dіduk ◽  
Nailia Kashapova ◽  
Alina Pletenetska
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Head Injuries ◽  
Medical Examination ◽  
Simultaneous Occurrence ◽  
Craniocerebral Injuries ◽  
Medical Evaluation ◽  
High Incidence ◽  
Traumatic Effect ◽  
The Brain

The problem of studying the mechanisms of the occurrence of traumatic brain injury remains a very urgent issue for forensic medicine. The high incidence and high mortality rate of head injuries underlines its importance to experts. The article presents a case from the practice of a forensic medical examination of a traumatic brain injury. This case is indicative, since it clearly demonstrates the difficulties that forensic doctors face when examining craniocerebral injuries, when determining the mechanism of damage and the severity of bodily injuries. In this case, there is damage to the head and a concussion. The cited several conclusions of the experts of the bureau of forensic medical examination and the commission examination of the Main Bureau of Forensic Medical Examination of the Ministry of Health of Ukraine regarding the forensic medical assessment in the case of traumatic brain injury with damage to the head. When conducting an investigative experiment, it was determined that the simultaneous occurrence of an abrasion and a concussion of the brain with one traumatic effect in the glabellar region is unlikely. After all, a concussion of the brain and abrasions in the glabellar area were formed by different mechanisms. The results of this assessment of the characteristics of traumatic brain injury can be useful for preventing difficulties in establishing the mechanism of damage in further expert practice.

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