An Analytical Investigation of the Cavitation Hypothesis of Brain Damage

1970 ◽  
Vol 92 (3) ◽  
pp. 597-603 ◽  
Author(s):  
J. V. Benedict ◽  
E. H. Harris ◽  
D. U. von Rosenberg
Keyword(s):  
Shell Theory ◽  
Impact Load ◽  
Analytical Investigation ◽  
Variable Coefficients ◽  
Reduced Pressure ◽  
Linear Partial Differential Equations ◽  
The Impact ◽  
Acoustic Fluid ◽  
The Brain ◽  
Finite Difference Techniques

An analytic investigation of the cavitation hypothesis of brain injury is performed by designing a mathematical model of the skull and brain subjected to an impact load. The skull is characterized as a thin, homogeneous, isotropic, elastic spherical shell, and the brain is assumed to be an ideal acoustic fluid. Using extensional shell theory, the skull-brain system is described by three coupled, simultaneous, linear partial differential equations with variable coefficients. The equations are solved by finite difference techniques. Results demonstrate that two prime focal points of reduced pressure occur within the fluid shortly after the onset of impact. These are located at the impact pole and at the counter pole or “contrecoup” site.

The Effect of SAS Materials and Modeling in Transferring Impact Loads to the Brain

2010 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Brain Injuries ◽  
Impact Load ◽  
Compressive Load ◽  
Impact Loads ◽  
Modeling Methodology ◽  
Wide Range ◽  
The Impact ◽  
The Brain

While subarachnoid space (SAS) trabeculae play an important role in damping and reducing the relative movement of the brain with respect to the skull, thereby reducing traumatic brain injuries, their mechanical properties and modeling are not well established in the literature. A few studies, e.g., Zhang et al. (2002) and Xin Jin et al. (2008) have reported a wide range the elastic modulus of the trabeculae up to three orders of magnitudes. The histology of the trabeculae reveals a collagen based structure. Thus, a few investigators have estimated the mechanical properties of trabeculae based on collagen’s properties. The objective of this study is to determine the stress/strain changes in the brain as a function of the mechanical properties and modeling methodology of the trabeculae, when the loading and the boundary conditions of the model are kept the same. This study was performed through several modeling steps. A wide range of the mechanical properties of the trabeculae was employed and the transductions of blunt impact loads from the skull to the brain were determined. The mechanical properties of the SAS trabeculae were determined based on the validation of the models with experimental results of Sabet et al. (2009). The result indicated that when we use softer material properties for the trabeculae the meningeal layers absorb and damp the impact load. It is also concluded that the material properties of the trabeculae can be simulated by only tension element since the trabeculae buckles with minimal compressive load. Finally, an optimum material property of SAS was proposed.

Histology and Trabecular Architecture of the Brain for Modeling of Subarachnoid Space

2010 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Subarachnoid Space ◽  
Impact Load ◽  
Angular Acceleration ◽  
Trabecular Architecture ◽  
Solid Materials ◽  
Complex Architecture ◽  
The Impact ◽  
The Brain

Subarachnoid space (SAS) plays an important role in transferring and or damping the impact load or angular acceleration to the brain (Zoghi Sadegh 2009). Previous investigations have over simplified the complex architecture of the trabeculae of SAS and employed soft solid materials. The goal of this study is to investigate the histology, architecture and mechanotransduction of subarachnoid space and in particular the trabeculae. The results of this study facilitate future modeling of the brain and thereby better understanding of the TBI.

Evaluation of Drop Impact Load for Thin Cone-Shaped Structures

2007 ◽  
Vol 353-358 ◽  
pp. 2648-2651
Author(s):  
Takahiro Omori ◽  
Hirotsugu Inoue ◽  
Noriyasu Kawamura ◽  
Minoru Mukai ◽  
Kikuo Kishimoto ◽  
...  
Keyword(s):  
Shell Theory ◽  
Impact Load ◽  
Contact Stiffness ◽  
Drop Impact ◽  
Hertzian Contact ◽  
Contact Theory ◽  
Load Prediction ◽  
Stiffness Model ◽  
The Impact ◽  
Hertzian Contact Theory

A method to predict impact load caused by drop impact of thin cone-shaped structures is investigated. The Hertzian contact theory and the spherical shell theory are applied for modeling the contact stiffness of the impact tip of the cone. Experiments and finite element simulations are performed for several cones to evaluate the accuracy of impact load prediction. It is shown that appropriate choice of contact stiffness model depending on the curvature and thickness of impact tip of the cone is necessary in order to predict the impact load accurately.

Impact Load Buffering Method Based on Stress Wave Attenuation Principle

2019 ◽  
Vol 11 (02) ◽  
pp. 1950019 ◽  
Author(s):  
Lin Gan ◽  
He Zhang ◽  
Cheng Zhou ◽  
Lin Liu
Keyword(s):  
Stress Wave ◽  
Wave Attenuation ◽  
Impact Load ◽  
Dynamics Simulation ◽  
Scanning System ◽  
Isolation Method ◽  
Element Analysis ◽  
System A ◽  
High Emission ◽  
The Impact

Rotating scanning motor is the important component of synchronous scanning laser fuze. High emission overload environment in the conventional ammunition has a serious impact on the reliability of the motor. Based on the theory that the buffer pad can attenuate the impact stress wave, a new motor buffering Isolation Method is proposed. The dynamical model of the new buffering isolation structure is established by ANSYS infinite element analysis software to do the nonlinear impact dynamics simulation of rotating scanning motor. The effectiveness of Buffering Isolation using different materials is comparatively analyzed. Finally, the Macht hammer impact experiment is done, the results show that in the experience of the 70,000[Formula: see text]g impact acceleration, the new buffering Isolation method can reduce the impact load about 15 times, which can effectively alleviate the plastic deformation of rotational scanning motor and improve the reliability of synchronization scanning system. A new method and theoretical basis of anti-high overload research for Laser Fuze is presented.

scholarly journals A Rational Numerical Method for Simulation of Drop-Impact Dynamics of Oleo-Pneumatic Landing Gear

2021 ◽  
Vol 11 (9) ◽  
pp. 4136
Author(s):  
Rosario Pecora
Keyword(s):  
Numerical Method ◽  
Initial Conditions ◽  
Impact Load ◽  
Numerical Models ◽  
Landing Gear ◽  
Design Stage ◽  
Impact Dynamics ◽  
State Variables ◽  
Adopted Model ◽  
The Impact

Oleo-pneumatic landing gear is a complex mechanical system conceived to efficiently absorb and dissipate an aircraft’s kinetic energy at touchdown, thus reducing the impact load and acceleration transmitted to the airframe. Due to its significant influence on ground loads, this system is generally designed in parallel with the main structural components of the aircraft, such as the fuselage and wings. Robust numerical models for simulating landing gear impact dynamics are essential from the preliminary design stage in order to properly assess aircraft configuration and structural arrangements. Finite element (FE) analysis is a viable solution for supporting the design. However, regarding the oleo-pneumatic struts, FE-based simulation may become unpractical, since detailed models are required to obtain reliable results. Moreover, FE models could not be very versatile for accommodating the many design updates that usually occur at the beginning of the landing gear project or during the layout optimization process. In this work, a numerical method for simulating oleo-pneumatic landing gear drop dynamics is presented. To effectively support both the preliminary and advanced design of landing gear units, the proposed simulation approach rationally balances the level of sophistication of the adopted model with the need for accurate results. Although based on a formulation assuming only four state variables for the description of landing gear dynamics, the approach successfully accounts for all the relevant forces that arise during the drop and their influence on landing gear motion. A set of intercommunicating routines was implemented in MATLAB® environment to integrate the dynamic impact equations, starting from user-defined initial conditions and general parameters related to the geometric and structural configuration of the landing gear. The tool was then used to simulate a drop test of a reference landing gear, and the obtained results were successfully validated against available experimental data.

scholarly journals Miniaturization and Automation of a Human In Vitro Blood–Brain Barrier Model for the High-Throughput Screening of Compounds in the Early Stage of Drug Discovery

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 892
Author(s):  
Elisa L. J. Moya ◽  
Elodie Vandenhaute ◽  
Eleonora Rizzi ◽  
Marie-Christine Boucau ◽  
Johan Hachani ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Blood Brain Barrier ◽  
Early Stage ◽  
Molecular Transport ◽  
Brain Barrier ◽  
Blood Brain ◽  
Cns Drugs ◽  
The Impact ◽  
The Brain

Central nervous system (CNS) diseases are one of the top causes of death worldwide. As there is a difficulty of drug penetration into the brain due to the blood–brain barrier (BBB), many CNS drugs treatments fail in clinical trials. Hence, there is a need to develop effective CNS drugs following strategies for delivery to the brain by better selecting them as early as possible during the drug discovery process. The use of in vitro BBB models has proved useful to evaluate the impact of drugs/compounds toxicity, BBB permeation rates and molecular transport mechanisms within the brain cells in academic research and early-stage drug discovery. However, these studies that require biological material (animal brain or human cells) are time-consuming and involve costly amounts of materials and plastic wastes due to the format of the models. Hence, to adapt to the high yields needed in early-stage drug discoveries for compound screenings, a patented well-established human in vitro BBB model was miniaturized and automated into a 96-well format. This replicate met all the BBB model reliability criteria to get predictive results, allowing a significant reduction in biological materials, waste and a higher screening capacity for being extensively used during early-stage drug discovery studies.

scholarly journals The Impact of Bone on the Biology of Aging

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 740-740
Author(s):  
Gerard Karsenty
Keyword(s):  
Muscle Function ◽  
Male Fertility ◽  
Leydig Cells ◽  
Memory Loss ◽  
Age Related ◽  
Systematic Exploration ◽  
Biology Of Aging ◽  
The Impact ◽  
The Brain ◽  
Regulate Energy Metabolism

Abstract We hypothesized that bone may secrete hormones that regulate energy metabolism and reproduction. Testing this hypothesis revealed that the osteoblast-specific secreted protein osteocalcin is a hormone regulating glucose homeostasis and male fertility by signaling through a GPCR, Gprc6a, expressed in pancreatic β bells and Leydig cells of the testes. The systematic exploration of osteocalcin biology, revealed that it regulates an unexpectedly large spectrum of physiological functions in the brain and peripheral organs and that it has most features of an antigeromic molecule. As will be presented at the meeting, this body of work suggests that harnessing osteocalcin for therapeutic purposes may be beneficial in the treatment of age-related diseases such as depression, age-related memory loss and the decline in muscle function seen in sarcopenia.

scholarly journals Crosstalk between Existential Phenomenological Psychotherapy and Neurological Sciences in Mood and Anxiety Disorders

Biomedicines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 340
Author(s):  
Lehel Balogh ◽  
Masaru Tanaka ◽  
Nóra Török ◽  
László Vécsei ◽  
Shigeru Taguchi
Keyword(s):  
Anxiety Disorders ◽  
Biological Treatment ◽  
Sense Of Self ◽  
Phenomenological Approach ◽  
Neurological Damage ◽  
Mood And Anxiety Disorders ◽  
New Interpretation ◽  
And Behavior ◽  
The Impact ◽  
The Brain

Psychotherapy is a comprehensive biological treatment modifying complex underlying cognitive, emotional, behavioral, and regulatory responses in the brain, leading patients with mental illness to a new interpretation of the sense of self and others. Psychotherapy is an art of science integrated with psychology and/or philosophy. Neurological sciences study the neurological basis of cognition, memory, and behavior as well as the impact of neurological damage and disease on these functions, and their treatment. Both psychotherapy and neurological sciences deal with the brain; nevertheless, they continue to stay polarized. Existential phenomenological psychotherapy (EPP) has been in the forefront of meaning-centered counseling for almost a century. The phenomenological approach in psychotherapy originated in the works of Martin Heidegger, Ludwig Binswanger, Medard Boss, and Viktor Frankl, and it has been committed to accounting for the existential possibilities and limitations of one’s life. EPP provides philosophically rich interpretations and empowers counseling techniques to assist mentally suffering individuals by finding meaning and purpose to life. The approach has proven to be effective in treating mood and anxiety disorders. This narrative review article demonstrates the development of EPP, the therapeutic methodology, evidence-based accounts of its curative techniques, current understanding of mood and anxiety disorders in neurological sciences, and a possible converging path to translate and integrate meaning-centered psychotherapy and neuroscience, concluding that the EPP may potentially play a synergistic role with the currently prevailing medication-based approaches for the treatment of mood and anxiety disorders.

scholarly journals Analysis on Force Transmission Characteristics of Two-Legged Shield Support under Impact Loading

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Qing-liang Zeng ◽  
Zhao-sheng Meng ◽  
Li-rong Wan ◽  
Cheng-long Wang
Keyword(s):  
Structural Design ◽  
Load Transfer ◽  
Impact Load ◽  
Force Transmission ◽  
Full Account ◽  
Flexible Bodies ◽  
Powered Support ◽  
Structural Design Optimization ◽  
Hinge Points ◽  
The Impact

To study the load transfer characteristics of a two-legged shield powered support, a numerical simulation model of the support was established using the multibody dynamics software ADAMS. The model took full account of the hydraulic-elastic deformation characteristics of the support, as a series spring-damper system was used to replace the leg and the equilibrium jack. The canopy, goaf shield, lemniscate bars, and equilibrium jack are equivalent to flexible bodies. The setting force of the leg was provided by the preload of the equivalent spring, the static roof load was simulated using a slope signal, and the impact load was simulated using a step signal. Using the model, the impact and excitation effects of each hinge joint of the support were analyzed under different impact load conditions across the canopy. The results show that the location of the impact load affects the force transmissions of all hinge points of the support. Both the impact effect and the excitation effect are at a minimum when the impact force is located near the leg action line. These results are useful for the adaptive control and structural design optimization of the support.

scholarly journals The influence of advance speed on overburden movement characteristics in longwall coal mining: insight from theoretical analysis and physical simulation

2021 ◽  
Vol 18 (1) ◽  
pp. 163-176
Author(s):  
Penghua Han ◽  
Cun Zhang ◽  
Zhaopeng Ren ◽  
Xiang He ◽  
Sheng Jia
Keyword(s):  
Physical Simulation ◽  
Impact Load ◽  
Main Roof ◽  
Longwall Face ◽  
Mine Safety ◽  
Efficient Production ◽  
Time Space ◽  
Mining Pressure ◽  
The Impact ◽  
Advance Speed

Abstract The advance speed of a longwall face is an essential factor affecting the mining pressure and overburden movement, and an effective approach for choosing a reasonable advance speed to realise coal mine safety and efficient production is needed. To clarify the influence of advance speed on the overburden movement law of a fully mechanised longwall face, a time-space subsidence model of overburden movement is established by the continuous medium analysis method. The movement law of overburden in terms of the advance speed is obtained, and mining stress characteristics at different advance speeds are reasonably explained. The theoretical results of this model are further verified by a physical simulation experiment. The results support the following conclusions. (i) With increasing advance speed of the longwall face, the first (periodic) rupture interval of the main roof and the key stratum increase, while the subsidence of the roof, the fracture angle and the rotation angle of the roof decrease. (ii) With increasing advance speed, the roof displacement range decreases gradually, and the influence range of the advance speed on the roof subsidence is 75 m behind the longwall face. (iii) An increase in the advance speed of the longwall face from 4.89 to 15.23 m/d (daily advancing of the longwall face) results in a 3.28% increase in the impact load caused by the sliding instability of the fractured rock of the main roof and a 5.79% decrease in the additional load caused by the rotation of the main roof, ultimately resulting in a 9.63% increase in the average dynamic load coefficient of the support. The roof subsidence model based on advance speed is proposed to provide theoretical support for rational mining design and mining-pressure-control early warning for a fully mechanised longwall face.

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