A Mechanistic End-to-End Concussion Model That Translates Head Kinematics to Neurologic Injury.

Past concussion studies have focused on understanding the injury processes occurring on discrete length scales (e.g., tissue-level stresses and strains, cell-level stresses and strains, or injury-induced cellular pathology).

A model for predicting primary blast lung injury.

Background: This article presents a model-based method for predicting primary blast injury. On the basis of the normalized work injury mechanism from previous work, this method presents a new model that accounts for the effects of blast orientation and species difference.

Methods: The analysis used test data from a series of extensive experimental studies sponsored by the US Army Medical Research and Materiel Command.

Assessing the application of acute toxic gas standards.

Objective: In this paper, we compare acute toxic gas standards developed for occupational, military, and civilian use that predict or establish guidelines for limiting exposure to inhaled toxic gases.

Context: Large disparities between guidelines exist for similar exposure scenarios, raising questions about why differences exist, as well as the applicability of each standard. The motivation and rationale behind the development of the standards is explored with emphasis on the experimental data used to set the standards.

An integrated exercise response and muscle fatigue model for performance decrement estimates of workloads in oxygen-limiting environments.

The performance dynamic physiology model (DPM-PE) integrates a modified muscle fatigue model with an exercise physiology model that calculates the transport and delivery of oxygen to working muscles during exposures of oxygen-limiting environments. This mathematical model implements a number of physiologic processes (respiration, circulation, tissue metabolism, diffusion-limited gas transfer at the blood/gas lung interface, and ventilatory control with afferent feedback, central command and humoral chemoreceptor feedback) to replicate the three phases of ventilatory response to a variety of exertion patterns, predict the delivery and transport of oxygen and carbon dioxide from the lungs to tissues, and calculate the amount of aerobic and anaerobic work performed. The ventilatory patterns from passive leg movement, unloaded work, and stepped and ramping loaded work compare well against data.

Development and validation of subject-specific finite element models for blunt trauma study.

This study developed and validated finite element (FE) models of swine and human thoraxes and abdomens that had subject-specific anatomies and could accurately and efficiently predict body responses to blunt impacts. Anatomies of the rib cage, torso walls, thoracic, and abdominal organs were reconstructed from X-ray computed tomography (CT) images and extracted into geometries to build FE meshes. The rib cage was modeled as an inhomogeneous beam structure with geometry and bone material parameters determined directly from CT images.

Incorporation of acute dynamic ventilation changes into a standardized physiologically based pharmacokinetic model.

A seven-compartment physiologically based pharmacokinetic (PBPK) model incorporating a dynamic ventilation response has been developed to predict normalized internal dose from inhalation exposure to a large range of volatile gases. The model uses a common set of physiologic parameters, including standardized ventilation rates and cardiac outputs for rat and human. This standardized model is validated against experimentally measured blood and tissue concentrations for 21 gases.

Finite element models of rib as an inhomogeneous beam structure under high-speed impacts.

Fracture of ribs commonly occurs during blunt impacts and can lead to serious injuries or even fatality. The finite element (FE) modeling of ribs under impacts, however, is difficult due to the complex geometry, the difficulty in determining material parameters, and the amount of the computational time required. This study develops a method of modeling ribs as inhomogeneous beam structures.

An internal dose model of incapacitation and lethality risk from inhalation of fire gases.

A mathematical model for estimating the likelihood of incapacitation and lethality from the inhalation of toxic gases is presented. The model computes an internal dose, equal to retained toxic gas per body mass, which is used to extrapolate outcomes across species. Account is taken for ventilation changes due to species, activity, and chemical response.

Biomechanically based criteria for rib fractures induced by high-speed impact.

Biomechanically based correlations for rib fractures induced by high-speed impact were developed from animal studies, finite-element simulations, and statistical analysis. Using subject-specific finite-element models of swine thorax developed from medical images and customized for each animal subject, simulations were conducted for animal tests. The peak motions, internal forces, stresses, and strains were calculated for individual ribs.

A mathematical model of ventilation response to inhaled carbon monoxide.

A comprehensive mathematical model, describing the respiration, circulation, oxygen metabolism, and ventilatory control, is assembled for the purpose of predicting acute ventilation changes from exposure to carbon monoxide in both humans and animals. This Dynamic Physiological Model is based on previously published work, reformulated, extended, and combined into a single model. Model parameters are determined from literature values, fitted to experimental data, or allometrically scaled between species.

The metabolic cost of force generation.

Introduction: The purpose of this study was to provide support, based on a review of existing data, for a general relationship between metabolic cost and force generated. There are confounding factors that can affect metabolic cost, including muscle contraction type (isometric, eccentric, or concentric), length, and speed as well as fiber type (e.g.

An internal dose model for interspecies extrapolation of immediate incapacitation risk from inhalation of fire gases.

A quantitative mathematical model assesses incapacitation risk in humans from toxic gas inhalation. A body-mass-normalized internal dose for each gas is calculated from an inhalation equation in which ventilation is a function of species, activity, and the gases inhaled. Uptake in the dead space considers U.