Search

A simulation model was developed to better understand the mechanisms of brain injuries in sports. A three-dimensional model comprising approximately 1.22 million elements was constructed from cranial computed tomography images of adult male volunteers by the voxel method. To simulate contact sports that permit actions such as tackling, a sinusoidal wave with duration of 10 ms and maximum acceleration of 2000 m/s2 was applied to the lowest point of the model to apply rotational acceleration to the head from different directions. The von Mises stress was then observed at five points in the coronal plane of the brain: cingulate gyrus (CG), corpus callosum (CC), brain stem (BS), lateral temporal lobe (LT), and medial temporal lobe (MT). LS-DYNA universal finite element analysis software with explicit time integration was used for the analysis. Concentrations of stress started to appear in the CC and BS at 10 ms post-impact, after which they also became evident in the CG and MT. The maximum changes in stress at each location occurred 10-15 ms post-impact. The von Mises stress was 9-14 kPa in the CG, 8-24 kPa in the CC, 12-24 kPa in the BS, 7-12 kPa in the LT, and 12-18 kPa in the MT. The highest stress in every part of the brain occurred after lateral impact, followed by oblique impact and sagittal impact. Such simulations may help elucidate the mechanisms of brain injuries in sports and help develop measures to prevent chronic traumatic encephalopathy.

In this paper, a three-dimensional digital human-head model was developed and several dynamic analyses on the head trauma were conducted. This model was built up by the VOXEL approach using 433 slice CT images (512×512 pixels) and made of 1.22 million parallelepiped finite elements with 10 anatomical tissue properties such as scalp, CSF, skull, brain, dura mater and so on. The numerical analyses were conducted using a finite element code the authors have developed. The main features of the code are 1) it is based on the explicit time integration method and 2) it uses the one point integration method to evaluate the equivalent nodal forces with the hourglass control proposed by Flanagan and Belytschko(1) and 3) it utilizes the parallel computation system based on MPI. In order to verify the developed model, the head impact experiment for a cadaver by Nahum et al.(2) was simulated. The calculated results showed good agreement with the experimental ones. A front and rear impact analyses were also performed to discuss on the characteristic measure of the brain injury, in which the von-Mises stress was high in the frontal lobe in both of the analyses because of the large deformations of a frontal cranial base. This result suggests that the von-Mises stress can be a good measure of the brain injury since it is empirically well known that the frontal lobe tends to get injured regardless of the impact positions.

In this paper, a three-dimensional digital human-head model was developed and several dynamic analyses on the head trauma were conducted. This model was built up by the VOXEL approach using 433 slice CT images (512×512 pixels) and made of 1.22 million parallelepiped finite elements with 10 anatomical tissue properties such as scalp, CSF, skull, brain, dura mater and so on. The numerical analyses were conducted using a finite element code the authors have developed. The main features of the code are 1) it is based on the explicit time integration method and 2) it uses the one point integration method to evaluate the equivalent nodal forces with the hourglass control proposed by Flanagan and Belythcko and 3) it utilizes the parallel computation with the MPI. In order to verify the developed model, the head impact experiment for a cadaver by Nahum et al. was simulated. The calculated results showed good agreement with experimental ones. A front and rear impact analyses were also performed investigate the relation between the impact direction and the positions of the high measurement of pressure and stresses in brain. The obtained results represent that brain injury has a closer relation with the Mises equivalent stress rather than the pressure. At this time, the large deformation of a frontal cranial base was observed in both frontal and occipital impact analyses. We expect that it induces the brain injury in a frontal lobe regardless of the impact positions.

The brain is the most important organ for life activity and humanity and is also an organ that tends to have residual disabilities after an accident because neuron cells cannot repair themselves. Therefore, protecting the brain from serious damage should be one of the most important objectives in automotive safety design for both passengers and pedestrians. For this reason, the Seikei University Graduate School and others have examined head impacts and the subsequent responses.

A 68-year-old woman presented with an extremely rare intracranial metastasis from a gastrointestinal stromal tumor (GIST) manifesting as left hemiparesis 2 years after resection of a sacral tumor adjacent to the coccygeal bone. Magnetic resonance imaging revealed an intracranial tumor in the right parietal lobe. Craniotomy was performed to completely remove the tumor. Although the tumor was located extra-axially, only internal carotid angiography showed mass staining. Seven months after surgery, the tumor recurred. Repeat craniotomy was performed to remove the recurrent tumor. Immunohistochemical analysis showed that the tumor cells were positive for c-kit and CD34, and the tumors were identified as intracranial metastasis of GIST. Following the second intracranial surgery, the patient developed severe lower back pain caused by metastatic tumor invading the lumbar spine and ureter. To avoid surgical complications and to reduce tumor volume, imatinib mesylate (Gleevec®) was administered. The severe pain was relieved, although the tumor was not reduced. In this case, the extra-axial tumor was fed only by the internal carotid artery.

A 46-year-old woman was admitted with generalized convulsion and deep coma which occurred 3 weeks after sudden onset of severe headache and pyrexia. Initial computed tomography did not reveal any abnormal findings except for an arachnoid cyst in the right middle fossa. Three weeks later repeat computed tomography showed intracystic hematoma in the arachnoid cyst with uncal herniation. Angiography revealed a right internal carotid-posterior communicating artery aneurysm. The neck of the aneurysm was clipped successfully, but hemiparesis was persistent postoperatively. Angiography is required for investigation of intracystic hematoma of an arachnoid cyst, especially in the absence of head injury, to avoid delayed diagnosis of any ruptured aneurysm.

A rare case of central retinal artery occlusion associated with internal carotid artery stenosis due to closed head and neck injuries is reported. A five-year-old boy was hit over the head and neck in an automobile accident. On admission, he was semicomatose and had sustained a subcutaneous hematoma in the right occipital region, face and the right side of the neck. Craniograms revealed a linear skull fracture in the occipital bone. Computed tomography did not show intracranial mass lesions but mild brain swelling. Three weeks after the injury, he complained of blurred vision in the right eye. An angiogram of the right common carotid artery disclosed right internal carotid artery stenosis. It is suggested that the central retinal artery occlusion resulted from an embolism due to thrombosis of the internal carotid artery. Traumatic thrombosis of the internal carotid artery should be considered whenever a patient who has suffered a head or neck injury exhibits progressive neurological deterioration without an intracranial hematoma.

二輪車交通事故における頭部外傷のメカニズムを検討する目的で,臨床情報をふまえて事故後回収したヘルメット120例について分析を加えた。臨床データから頭部外傷の程度によって負傷者を軽症,重症,死亡に分類した。また,障害の内容も細分しそれぞれの延べ数を求めた。ヘルメットは外表の観察にとどめず,切断して衝撃吸収ライナーとして使用されている発泡スチロールの状態も検査した。この方法によりヘルメットの損傷部位と程度を評価した。ヘルメットが事故に際し脱落したもの(脱落例)では脱落しなかったもの(非脱落例)に比べ障害が重症となる傾向を示した。局所性脳損傷は脱落例で多いのに対し,びまん性脳損傷は脱落例,非脱落例で明らかな差はみられなかった。ヘルメットの分析結果から衝撃の強さと方向を推定し頭部外傷の傷害内容と比較したところ,急性硬膜下血腫ではヘルメットの辺縁部に前後方向から衝撃を受けた場合に生じやすく,びまん性軸索損傷は円蓋部に横方向から衝撃を受けた場合に生じやすかった。脳組織の損傷メカニズムとして,実験的に回転外力でびまん性脳損傷が生じやすいことが証明されている。ヘルメットの円蓋部を打ったときにびまん性軸索損傷が多かったのは,ヘルメットの円蓋部への衝撃では頭部の重心より上部に外力が加わり,辺縁部への衝撃に比べ回転外力が生じやすいためと考えられた。急性硬膜下血腫,脳挫創,びまん性軸索損傷などの重症の脳外傷はヘルメットの損傷の強い場合が多かった。ヘルメットにそのような損傷を来す外力がヘルメットを着用せず直接頭部に加わっていたならば,さらに重篤な脳損傷を来して死亡していた可能性が強いと推定された。したがって,重症度の軽減の面からはヘルメットは十分に脳保護作用を発揮していると考えられる。

Despite the relative rarity of school shootings, targeted violence, and school-associated violent deaths, any youth who presents with words, gestures, or actions of a threatening or violent nature in a school setting should be assessed and referred for further evaluation by a mental health professional and, if clinically indicated, a forensic evaluator.The request for a juvenile risk assessment for future dangerousness requires careful delineation of role and agency; confidentiality issues; a comprehensive diagnostic evaluation of the youth; and a detailed assessment of the youth's perceived threat or problematic behavior. Various protective and risk factors and consideration of other individual, family, school/peer, and situational factors should also be explored.There is still much information that is unknown when considering school violence or targeted school violence. There is clearly a need for additional research on the identification of at-risk youths, the contributions and significance of various protective and risk factors, the impact of peer relationships, and perceived rejection, socioeconomic status, subtypes of aggression, and developmental stages. Examples of future research direction might include difference by gender, presence of affective or psychotic disorders, substance abuse, emerging characterologic disturbances, and physiologic markers, such as cortisol or serotonin. Additional research regarding best practices and the development of clinical guidelines or practice parameters is also needed.

In this paper, a three-dimensional human-head model was developed using the VOXEL approach. The human-head VOXEL model is based on 433 scanned images (512 x 512 pixels) taken by CT (Computed Tomography). The precision of the head model depends on the resolution of slice images. The number of elements is then defined by the resolution and number of slice images. The maximum number of elements for a human-head VOXEL model developed from slice images is about 40.0 million. This model included the scalp, soft tissue, subarachnoid space, eyes, skull, brain, falx cerebri, dura mater, tentorium cerebelli and ventricles. All of these biological tissues were modeled as tiny cubic elements with one-point integration. To investigate the relation between CPU time and the number of elements, finite-element analysis was conducted using an original finite-element analysis code. Direct-impact analysis was conducted frontally on the human-head VOXEL model by a cylinder to simulate the cadaveric tests.

Occupational populations have become increasingly diverse, requiring novel accommodation technologies for inclusive design. Hence, further attention is required to identify potential differences in work perception between workers with varying physical limitations. The major aim of this study was to identify differences in shoulder loading and perception of effort between a control population (C) and populations affected by chronic back pain (LBP) and spinal cord injury (SCI) in one-handed seated transfer tasks to targets. The effects of the injuries, and associated pain, are likely to produce variations in movement patterns, muscle loading and perceived effort. The main results show that a) the LBP group had the highest movement time required for an exertion; significantly higher than both the SCI and C groups, while the SCI group had significantly longer exertion times than group C, b) the SCI and LBP groups had significantly higher total, maximum, and mean shoulder torques than the C group, c) the mean shoulder effort ratings for LBPs and SCIs were significantly higher than those for Cs, d) LBPs reported higher shoulder effort ratings than SCIs, e) SCIs and/or LBPs were unable to reach some of the targets; and f) the perception of effort tended to increase as a function of the linear distance between the seat and the target shelf. Differences in shoulder loading and perception were attributed to differences in movement velocities and strategies between the groups. These results suggest that workplace adaptation must take into account population specific characteristics.

This paper presents results of an investigation of evaluating the bridges health degree of 54 bridges managed by Gifu Prefecture in Gifu City. Bridge health degree is statistically calculated with periodic inspection data conducted by Gifu Prefecture. This inspection results consist of many items and evaluate the state of bridge details, but a currently index is insufficient as one used to maintenance. Accordingly, the index is required that can evaluate overall of each bridge elements or entire bridge. So, this study aims to express health degree of bridge elements by one or two overall index with principal component analysis, and grasped relationship to calculated health index, age, specification, design standard and environmental condition by multiple regression analysis.

The first step of the study was animal experiments using eighty-five monkeys in close cooperation with engineers from the Japan Automobile Research Institute (JARI).The dynamic mechanism of craniocerebral injury was investigated which resulted in development of the JARI Human Head Impact Tolerance Curve (JHTC). The second step consisted of a series of drop tests using a dummy head wearing a safety helmet. Dynamic data recorded at the moment of impact to the head were evaluated on the basis of JHTC. A crush mark left on the helmet which reflected hight of drop was investigated, too. It was concluded that an impact of approrimateley 21 Km/h was the upper limit under which a helmet could protect a human head from danger.

The case of a patient with a chronic encapsulated intracerebral hematoma associated with a cavernous angioma is reported. In spite of a huge space-occupying lesion in the frontal lobe, our patient showed no focal neurological deficit. The clinical picture suggested a slowly growing brain tumor. Intraoperative findings revealed a liquefied intracerebral hematoma with a thick capsule. Pathological investigations demonstrated a capsule rich in neovascularity with a cavernous angioma attached to it. It is presumed that initial bleeding from the cavernous angioma encouraged capsule formation similar to the membrane of chronic subdural hematomas and that repeated bleeding from the capillaries of the capsule allowed the expansion of the hematoma.