Dynamic Response of Brain Subjected to Blast Loadings: Influence of Frequency Ranges

Blast wave induced a frequency spectrum and large deformation of the brain tissue. In this study, new material parameters for the brain material are determined from the experimental data pertaining to these large strain amplitudes and wide frequencies ranging (from 0.01 Hz to 10 MHz) using genetic algorithms. Both hyperelastic and viscoelastic behavior of the brain are implemented into 2D finite element models and the dynamic responses of brain are evaluated. The head, composed of triple layers of the skull, including two cortical layers and a middle dipole sponge-like layer, the dura, cerebrospinal fluid (CSF), the pia mater and the brain, is utilized to assess the effects of material model. The results elucidated that frequency ranges of the material play an important role in the dynamic response of the brain under blast loading conditions. An appropriate material model of the brain is essential to predict the blast-induced brain injury

Dynamic Response of Brain Subjected to Blast Loadings: Influence of Frequency Ranges

Blast wave induced a frequency spectrum and large deformation of the brain tissue. In this study, new material parameters for the brain material are determined from the experimental data pertaining to these large strain amplitudes and wide frequencies ranging (from 0.01 Hz to 10 MHz) using genetic algorithms. Both hyperelastic and viscoelastic behavior of the brain are implemented into 2D finite element models and the dynamic responses of brain are evaluated. The head, composed of triple layers of the skull, including two cortical layers and a middle dipole sponge-like layer, the dura, cerebrospinal fluid (CSF), the pia mater and the brain, is utilized to assess the effects of material model. The results elucidated that frequency ranges of the material play an important role in the dynamic response of the brain under blast loading conditions. An appropriate material model of the brain is essential to predict the blast-induced brain injury

Role of helmet in the mechanics of shock wave propagation under blast loading conditions

The effectiveness of helmets in extenuating the primary shock waves generated by the explosions of improvised explosive devices is not clearly understood. In this work, the role of helmet on the overpressurization and impulse experienced by the head were examined. The shock wave–head interactions were studied under three different cases: (i) unprotected head, (ii) head with helmet but with varying head–helmet gaps and (iii) head covered with helmet and tightly fitting foam pads. The intensification effect was discussed by examining the shock wave flow pattern and verified with experiments. A helmet with a better protection against shock wave is suggested

Case Report: Kikuchi-Fujimoto disease: a diagnostic and therapeutic dilemma following pretransplant nephrectomy for a 2.35 Kg kidney [version 1; referees: 2 approved]

Kikuchi-Fujimoto disease (KFD) is an extremely rare disease with a worldwide distribution and higher prevalence in Asians. It is a benign and self-limiting disorder, characterized by regional cervical lymphadenopathy accompanied with mild fever and night sweats. Lymph node histopathology is diagnostic and treating physicians should be aware of this entity as it may mimic other systemic diseases like systemic lupus erythematosus, tuberculosis, malignant lymphoma, and more rarely adenocarcinoma. Key features on lymph node biopsy are fragmentation, necrosis and karyorrhexis. Treatment includes symptomatic care, analgesics-antipyretics, corticosteroids and spontaneous recovery occurs in 1 to 4 months. We report a case of adult polycystic kidney disease (ADPKD) with end stage renal disease and episodes of fever and cervical lymphadenopathy. The infectious screen was negative and on extensive workup, the patient was found to have histiocytic-necrotizing lymphadenitis, which clinched the diagnosis of KFD