Publications by authors named "Michael Prange"

NMR relaxation and diffusion data analysis commonly uses a wide range of methods from simple exponential fitting to Laplace inversions. The pros and cons of these methods are often the subject of intense debate. We show that the ill-conditioned nature of such analysis gives rise to a range of solutions for every method resulting in uncertainty in the spectral solution.

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Pediatric cervical spine biomechanics have been under-researched due to the limited availability of pediatric post-mortem human subjects (PMHS). Scaled data based on human adult and juvenile animal studies have been utilized to augment the limited pediatric PMHS data that exists. Despite these efforts, a significant void in pediatric cervical spine biomechanics remains.

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Relaxation and diffusion data are often analyzed using a Laplace inversion algorithm that incorporates regularization. Regularization is used because Laplace inversion with finite and noisy data is an ill-conditioned problem for which many solutions exist for a given data set. This paper reports a different approach.

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The adult head has been studied extensively and computationally modeled for impact, however there have been few studies that attempt to quantify the mechanical properties of the pediatric skull. Likewise, little documentation of pediatric anthropometry exists. We hypothesize that the properties of the human pediatric skull differ from the human adult skull and exhibit viscoelastic structural properties.

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The objective of this study was to utilize tissue deformation thresholds associated with acute axonal injury in the immature brain to predict the duration of unconsciousness. Ten anesthetized 3- to 5-day-old piglets were subjected to nonimpact axial rotations (110-260 rad/s) producing graded injury, with periods of unconsciousness from 0 to 80 min. Coronal sections of the perfusion-fixed brain were immunostained with neurofilament antibody (NF-68) and examined microscopically to identify regions of swollen axons and terminal retraction balls.

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New vehicle safety standards are designed to limit the amount of neck tension and extension seen by out-of-position motor vehicle occupants during airbag deployments. The criteria used to assess airbag injury risk are currently based on volunteer data and animal studies due to a lack of bending tolerance data for the adult cervical spine. This study provides quantitative data on the flexion-extension bending properties and strength on the male cervical spine, and tests the hypothesis that the male is stronger than the female in pure bending.

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Object: Rotational loading conditions have been shown to produce subdural hemorrhage and diffuse axonal injury. No experimental data are available with which to compare the rotational response of the head of an infant during accidental and inflicted head injuries. The authors sought to compare rotational deceleration sustained by the head among free falls, from different heights onto different surfaces, with those sustained during shaking and inflicted impact.

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The large strain mechanical properties of adult porcine gray and white matter brain tissues were measured in shear and confirmed in compression. Consistent with local neuroarchitecture, gray matter showed the least amount of anisotropy, and corpus callosum exhibited the greatest degree of anisotropy. Mean regional properties were significantly distinct, demonstrating that brain tissue is inhomogeneous.

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