@article{segal_kepler_kimbell_2008, title={Effects of differences in nasal anatomy on airflow distribution: A comparison of four individuals at rest}, volume={36}, ISSN={["1573-9686"]}, DOI={10.1007/s10439-008-9556-2}, abstractNote={Differences in nasal anatomy among human subjects may cause significant differences in respiratory airflow patterns and subsequent dosimetry of inhaled gases and particles in the respiratory tract. This study used computational fluid dynamics (CFD) to study inter-individual differences in nasal airflow among four healthy individuals. Magnetic resonance imaging (MRI) scans were digitized and nasal-surface-area-to-volume ratios (SAVR) were calculated for 15 adults. Two males and two females, representative of the range of SAVR values, were selected for flow analysis. Nasal CFD models were constructed for each subject by a semi-automated process that provided input to a commercial mesh generator to generate structured hexahedral meshes (Gambit, Fluent, Inc., Lebanon, NH, USA). Steady-state inspiratory laminar airflow at 15 L/min was calculated using commercial CFD software (FIDAP, Fluent, Inc., Lebanon, NH, USA). Streamline patterns, velocities, and helicity values were compared. In all subjects, the majority of flow passed through the middle and ventral regions of the nasal passages; however, the amount and location of swirling flow differed among individuals. Cross-sectional flow allocation analysis also indicated inter-individual differences. Laboratory water-dye experiments confirmed streamlines and velocity magnitudes predicted by the computational model. These results suggest that significant inter-individual differences exist in bulk airflow patterns in the nose.}, number={11}, journal={ANNALS OF BIOMEDICAL ENGINEERING}, author={Segal, Rebecca A. and Kepler, Grace M. and Kimbell, Julia S.}, year={2008}, month={Nov}, pages={1870–1882} }
 @article{struve_wong_marshall_kimbell_schroeter_dorman_2008, title={Nasal uptake of inhaled acrolein in rats}, volume={20}, ISSN={["1091-7691"]}, DOI={10.1080/08958370701864219}, abstractNote={An improved understanding of the relationship between inspired concentration of the potent nasal toxicant acrolein and delivered dose is needed to support quantitative risk assessments. The uptake efficiency (UE) of 0.6, 1.8, or 3.6 ppm acrolein was measured in the isolated upper respiratory tract (URT) of anesthetized naive rats under constant-velocity unidirectional inspiratory flow rates of 100 or 300 ml/min for up to 80 min. An additional group of animals was exposed to 0.6 or 1.8 ppm acrolein, 6 h/day, 5 days/wk, for 14 days prior to performing nasal uptake studies (with 1.8 or 3.6 ppm acrolein) at a 100 ml/min airflow rate. Olfactory and respiratory glutathione (GSH) concentrations were also evaluated in naive and acrolein-preexposed rats. Acrolein UE in naive animals was dependent on the concentration of inspired acrolein, airflow rate, and duration of exposure, with increased UE occurring with lower acrolein exposure concentrations. A statistically significant decline in UE occurred during the exposures. Exposure to acrolein vapor resulted in reduced respiratory epithelial GSH concentrations. In acrolein-preexposed animals, URT acrolein UE was also dependent on the acrolein concentration used prior to the uptake exposure, with preexposed rats having higher UE than their naive counterparts. Despite having increased acrolein UE, GSH concentrations in the respiratory epithelium of acrolein preexposed rats were higher at the end of the 80 min acrolein uptake experiment than their in naive rat counterparts, suggesting that an adaptive response in GSH metabolism occurred following acrolein preexposure.}, number={3}, journal={INHALATION TOXICOLOGY}, author={Struve, Melanie F. and Wong, Victoria A. and Marshall, Marianne W. and Kimbell, Julia S. and Schroeter, Jeffry D. and Dorman, David C.}, year={2008}, pages={217–225} }
 @article{kepler_richardson_morgan_kimbell_1998, title={Computer simulation of inspiratory nasal airflow and inhaled gas uptake in a rhesus monkey}, volume={150}, ISSN={["0041-008X"]}, DOI={10.1006/taap.1997.8350}, abstractNote={There is increasing evidence that inspiratory airflow patterns play a major role in determining the location of nasal lesions induced in rats by reactive, water-soluble gases such as formaldehyde and chlorine. Characteristic lesion patterns have also been seen in inhalation toxicity studies conducted in rhesus monkeys, the nasal anatomy of which resembles that of humans. To examine the hypothesis that regions of high airflow-dependent uptake and lesions occur in similar nasal locations in the primate, airflow and gas uptake patterns were simulated in an anatomically accurate computer model of the right nasal airway of a rhesus monkey. The results of finite-element simulations of steady-state inspiratory nasal airflow for the full range of resting physiological flow rates are reported. Simulated airflow patterns agreed well with experimental observations, exhibiting secondary flows in the anterior nose and streamlined flow posteriorly. Simulated airflow results were used to predict gas transport to the nasal passage walls using formaldehyde as an example compound. Results from the uptake simulations were compared with published observations of formaldehyde-induced nasal lesions in rhesus monkeys and indicated a strong correspondence between airflow-dependent transport patterns and local lesion sites. This rhesus computer model will provide a means for confirming the extrapolation of toxicity data between species by extrapolating rat simulation results to monkeys and comparing these predictions with primate lesion data.}, number={1}, journal={TOXICOLOGY AND APPLIED PHARMACOLOGY}, author={Kepler, GM and Richardson, RB and Morgan, KT and Kimbell, JS}, year={1998}, month={May}, pages={1–11} }