| 1. |
- Antona, Jacobo, 1981, et al.
(författare)
-
Rat brain kinematics and tissue strains associated to Diffuse Axonal Injuries induced by head rotational acceleration
- 2013
-
Ingår i: Proceedings of Computational Engineering Conference JSCES. ; 18
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An anatomically detailed finite element model of a rat head-neck complex has been developed from medical images. The model incorporates material properties from tissue indentation test data captured in the coronal plane from seven brain regions to account for non-homogeneity. The local brain-skull relative displacement has been validated against local brain-slip experimental data in which a thin pin was entered the cortex and rigidly attached to the skull prior to impact. The model is being used to improve the understanding of brain rotational kinematics and to develop brain tissue injury thresholds for Diffuse Axonal Injuries as detected through immuno-histology.
|
|
| 2. |
- Antona, Jacobo, 1981, et al.
(författare)
-
Traumatic Brain Injuries in Motor Vehicles Crashes
- 2017
-
Ingår i: JSAE Annual Congress, Yokohama, Japan, May 24 to 26, 2017. ; 20175258
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study estimates, by means of an analysis of accident data from the US, the incidence and risk of car crash related traumatic brain injuries for occupants in Japanese brand cars. The study incorporated crash type, crash severity, belt use and the victim's age and sex. Concussion risk was the highest among all traumatic brain injuries categories for all crash types and severities; females were at higher risks than males. When concussions were excluded, Subdural Haemorrhages, Intracranial Haemorrhages and Sub-Arachnoid Haemorrhages comprised the most frequent injury categories. Elderly occupants were at considerably higher risks than non-elderly for these bleeding injuries.
|
|
| 3. |
- Antona, Jacobo, 1981, et al.
(författare)
-
Validation of local brain kinematics of a novel rat brain finite element model under rotational acceleration and its application towards the clarification of Diffuse Axonal Injury mechanisms
- 2013
-
Ingår i: Proceeding of JSAE Annual Congress, Yokohama, Japan.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Relative brain-skull displacement under head rotational acceleration in rats was evaluated experimentally. For this, a thin pin was entered the cortex and rigidly attached to the skull prior to impact. For peak rotational accelerations of 1.7 Mrad/s2, the pin scarred the brain cortex; 1.2 mm superficially and less centrally. These measurements were used to validate the brain kinematics of a new anatomically detailed FE model of the head-neck complex of a rat. This model is intended to be used to clarify brain loading mechanisms and to develop brain tissue injury threshold for Diffuse Axonal Injuries as detected through immune-histology.
|
|
| 4. |
- Brolin, Karin, 1974, et al.
(författare)
-
Finite Element Musculoskeletal Model with Feedback Control to Simulate Spinal Postural Responses
- 2014
-
Ingår i: 7th World Congress of Biomechanics. ; July 6-11, Boston, USA:18-14
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Today, most Finite Element (FE) Human Body Models (HBMs) are intended for crash simulations and not for pre-crash events, due to the lack of active muscles. To study combined pre- and in crash events, muscle activity is essential. Therefore, this work presents a method to implement postural muscle responses in an FE HBM.The Total HUman Model for Safety (THUMS®) AM50 version 3.0 (Toyota Central Labs Inc, Nagakute, Japan) was chosen and a model of active musculature was added (Östh et al. 2012). The trunk, neck, upper and lower extremities were represented by 394 Hill-type line elements. Muscle activation levels were generated by seven proportional, integrative, and derivative feedback controllers for the controlled angles of the spine and upper extremities, Figure 1. For each controller, the deviation from the initial angle was used to generate correcting moment requests to the flexors and extensor muscles in the respective body region. Neural delay was implemented by a time offset for the controlled angle. The request was scaled with the maximum strength of the muscles and then passed through a muscle activation dynamics model.The model response was compared to an experimental volunteer study that measured muscle activity, kinematics, and boundary conditions for drivers and passengers, riding on rural roads in a passenger car, subjected to autonomous and driver braking. The experimental braking pulse was applied to the model seated in an FE model of the front seat and restrained with seat belts. The results show that postural feedback control can be utilized to model driver and passenger responses to autonomous braking interventions in the sagittal plane. However, the model overestimated head rotation for driver braking events. Volunteer muscle activity occurred prior to deceleration onset, which cannot be captured by the feedback control model. Therefore, a hypothesized anticipatory postural response was implemented by modifying the reference value of the feedback controllers based on the volunteer data. The result was earlier onset of muscle activity and a kinematic response that was within one standard deviation of the corresponding test data from volunteers performing maximum braking.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Brolin, Karin, 1974, et al.
(författare)
-
Towards omni-directional active human body models
- 2016
-
Ingår i: 6th International Symposium on Human Modeling and Simulation in Automotive Engineering, Heidelberg, GERMANY, October 20-21.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 8. |
|
|
| 9. |
- Cutcliffe, Hattie, et al.
(författare)
-
Gender Differences in Occupant Posture and Muscle Activity with Motorized Seat Belts
- 2015
-
Ingår i: The 24th ESV Conference Proceedings.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this study was to assess gender differences in the posture and muscular activity of occupants in response to pretension from motorized seatbelts. Male and female vehicle occupants were tested in both front seat positions during normal driving and autonomous braking. This data is useful for the development of human body models (HBM), and increases the understanding of the effects of motorized belts.Kinematics and electromyography (EMG) were analyzed for 18 volunteers (9 male, 9 female) subjected to autonomous braking (11 m/s2 deceleration) during real driving on rural roads. Two restraint configurations were tested: a standard belt and a motorized belt, activated 240 ms before the initiation of braking. Statistical comparison of volunteers’ posture and normalized EMG amplitudes was performed to understand differences incurred by the motorized belts, as well as to compare response across gender and role (occupant position within the vehicle). Data was analyzed both prior to and at vehicle deceleration, which occurred 240 ms after motorized belt onset.Motorized belts significantly affected all postural metrics, and significantly elevated the activity of all muscles compared to typical riding. Though increases in muscle activity were small at deceleration onset compared with typical riding for male occupants and female passengers, female drivers demonstrated significantly larger increases in muscular activity: between 5 and 13% of the maximum voluntary contraction (MVC). At deceleration onset, standard belts showed little change in posture or muscle activation, with the median changes being well within the ranges exhibited during typical riding for all groups (i.e. not distinguishable from typical riding). Typical riding postures of males and females were similar, as were muscular activation levels—generally less than 5% of the MVC. However, drivers exhibited significantly higher muscular activity in the arm and shoulder muscles than passengers.Limitations include the repeated nature of the testing, as prior work has shown that habituation across trials alters occupant response compared to that of unaware occupants. However, randomization of the trial order helped mitigate potential habituation effects. Another limitation is the sample size of 18 volunteers.An important finding of this study is that the increase in occupant muscular activation seen with motorized belts was gender-specific: at deceleration, the change in activation of most muscles was significantly different across gender and belt type, with female drivers exhibiting larger increases in muscular activation than male drivers or passengers of either gender, particularly in the arm muscles. These activations appeared to be startle responses, and may have implications for interactions with the steering wheel and motion during a braking or crash event. This warrants further studies and stresses the importance of quantifying male and female subjects separately in future studies of pre-crash systems.
|
|
| 10. |
- Davidsson, Johan, 1967, et al.
(författare)
-
A Model for Research on Penetrating Traumatic Brain Injuries
- 2019
-
Ingår i: Neuromethods. - New York, NY : Springer New York. - 1940-6045 .- 0893-2336. ; , s. 47-59
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The animal model presented here produces high-speed penetrating traumatic brain injuries (pen-TBI) to simulate a form of neurotrauma that is severe and is the prevailing TBI in warzones and in areas with high incidence of violence. Commonly, these neurotraumas involve laceration of brain tissue, accompanying hemorrhage, edema, and inflammation. This also occurs in the pen-TBI model designed for rats that is presented here. During trauma, a probe, constructed in one single unit in aluminum and guided by a probe holder, is propelled by a lead bullet and penetrates at high speed into the brain parenchyma of the anesthetized animal. The animal’s head is held in position in a purposely built stereotactic frame. This frame can be adjusted in position relative the tip of the probe so that the tip of the probe is positioned on the exposed dura, using three orthogonally arranged horizontal slides. This procedure will facilitate high similarity in probe penetration location. By adjusting the air pressure in the air-driven accelerator used to accelerate the lead bullet, a large range of probe velocities can be achieved; 110 m/s probe velocity is commonly used. Several probe tip shapes are available for use in the pen-TBI model; pointy, blunt, and flat. The distance the probe penetrates the brain can be controlled. A typical distance is 5.5 mm, and this distance has been found to be almost independent of probe velocity and probe tip shape. After the probe has penetrated the animal, the pen-TBI device facilitates removal of the probe without causing additional brain damage. To do so, the animal is removed using the horizontal slider on the device that moves the animal’s head away from the probe in the direction of probe travel. The pen-TBI device is easy to operate and requires limited pre-trauma and post-trauma surgery. The device induces a small cavity, primary injury in a greater volume of the brain than the cavity and secondary injuries in an even greater volume that is several times that of the primary injury volume. The model appears to produce identical injuries in terms of appearance and dimensions in-between animals of same sex and body mass. The device also produces substantial but short-lived intracranial brain pressure changes, some 8-bar overpressure in the contralateral ventricle has been recorded, with high repeatability.
|
|
