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Garcia G.J.M.,Medical College of Wisconsin | Schroeter J.D.,Applied Research Assoc. Inc. | Kimbell J.S.,University of North Carolina at Chapel Hill
Inhalation Toxicology | Year: 2015

Context: Inhaled nanoparticles can migrate to the brain via the olfactory bulb, as demonstrated in experiments in several animal species. This route of exposure may be the mechanism behind the correlation between air pollution and human neurodegenerative diseases, including Alzheimers disease and Parkinsons disease.Objectives: This article aims to (i) estimate the dose of inhaled nanoparticles that deposit in the human olfactory epithelium during nasal breathing at rest and (ii) compare the olfactory dose in humans with our earlier dose estimates for rats.Materials and methods: An anatomically-accurate model of the human nasal cavity was developed based on computed tomography scans. The deposition of 1-100 nm particles in the whole nasal cavity and its olfactory region were estimated via computational fluid dynamics (CFD) simulations. Our CFD methods were validated by comparing our numerical predictions for whole-nose deposition with experimental data and previous CFD studies in the literature.Results: In humans, olfactory dose of inhaled nanoparticles is highest for 1-2 nm particles with ∼1% of inhaled particles depositing in the olfactory region. As particle size grows to 100 nm, olfactory deposition decreases to 0.01% of inhaled particles.Discussion and conclusion: Our results suggest that the percentage of inhaled particles that deposit in the olfactory region is lower in humans than in rats. However, olfactory dose per unit surface area is estimated to be higher in humans in the 1-7 nm size range due to the larger inhalation rate in humans. These dose estimates are important for risk assessment and dose-response studies investigating the neurotoxicity of inhaled nanoparticles. © 2015 Informa Healthcare USA, Inc. All rights reserved: reproduction in whole or part not permitted.


Young L.A.,Physical Sciences, Inc | Rule G.T.,Physical Sciences, Inc | Bocchieri R.T.,Applied Research Assoc. Inc. | Burns J.M.,Physical Sciences, Inc
Seminars in Neurology | Year: 2015

Despite years of effort to prevent traumatic brain injuries (TBIs), the occurrence of TBI in the United States alone has reached epidemic proportions. When an external force is applied to the head, it is converted into stresses that must be absorbed into the brain or redirected by a helmet or other protective equipment. Complex interactions of the head, neck, and jaw kinematics result in strains in the brain. Even relatively mild mechanical trauma to these tissues can initiate a neurochemical cascade that leads to TBI. Civilians and warfighters can experience head injuries in both combat and noncombat situations from a variety of threats, including ballistic and blunt impact, acceleration, and blast. It is critical to understand the physics created by these threats to develop meaningful improvements to clinical care, injury prevention, and mitigation. Here the authors review the current state of understanding of the complex loading conditions that lead to TBI and characterize how these loads are transmitted through soft tissue, the skull and into the brain, resulting in TBI. In addition, gaps in knowledge and injury thresholds are reviewed, as these must be addressed to better design strategies that reduce TBI incidence and severity. © Georg Thieme Verlag KG Stuttgart New York.


Darquenne C.,University of California at San Diego | Fleming J.S.,National Health Research Institute | Fleming J.S.,University of Southampton | Katz I.,Air Liquide | And 7 more authors.
Journal of Aerosol Medicine and Pulmonary Drug Delivery | Year: 2016

Development of a new drug for the treatment of lung disease is a complex and time consuming process involving numerous disciplines of basic and applied sciences. During the 2015 Congress of the International Society for Aerosols in Medicine, a group of experts including aerosol scientists, physiologists, modelers, imagers, and clinicians participated in a workshop aiming at bridging the gap between basic research and clinical efficacy of inhaled drugs. This publication summarizes the current consensus on the topic. It begins with a short description of basic concepts of aerosol transport and a discussion on targeting strategies of inhaled aerosols to the lungs. It is followed by a description of both computational and biological lung models, and the use of imaging techniques to determine aerosol deposition distribution (ADD) in the lung. Finally, the importance of ADD to clinical efficacy is discussed. Several gaps were identified between basic science and clinical efficacy. One gap between scientific research aimed at predicting, controlling, and measuring ADD and the clinical use of inhaled aerosols is the considerable challenge of obtaining, in a single study, accurate information describing the optimal lung regions to be targeted, the effectiveness of targeting determined from ADD, and some measure of the drug's effectiveness. Other identified gaps were the language and methodology barriers that exist among disciplines, along with the significant regulatory hurdles that need to be overcome for novel drugs and/or therapies to reach the marketplace and benefit the patient. Despite these gaps, much progress has been made in recent years to improve clinical efficacy of inhaled drugs. Also, the recent efforts by many funding agencies and industry to support multidisciplinary networks including basic science researchers, R&D scientists, and clinicians will go a long way to further reduce the gap between science and clinical efficacy. Copyright © 2016 Mary Ann Liebert, Inc.


Brown A.D.,Aurora University | Beemer B.T.,University of Colorado at Boulder | Greene N.T.,Aurora University | Argo T.,Applied Research Assoc. Inc. | And 2 more authors.
PLoS ONE | Year: 2015

Hearing protection devices (HPDs) such as earplugs offer to mitigate noise exposure and reduce the incidence of hearing loss among persons frequently exposed to intense sound. However, distortions of spatial acoustic information and reduced audibility of low-intensity sounds caused by many existing HPDs can make their use untenable in high-risk (e.g., military or law enforcement) environments where auditory situational awareness is imperative. Here we assessed (1) sound source localization accuracy using a head-turning paradigm, (2) speech-in-noise recognition using a modified version of the QuickSIN test, and (3) tone detection thresholds using a two-alternative forced-choice task. Subjects were 10 young normal-hearing males. Four different HPDs were tested (two active, two passive), including two new and previously untested devices. Relative to unoccluded (control) performance, all tested HPDs significantly degraded performance across tasks, although one active HPD slightly improved high-frequency tone detection thresholds and did not degrade speech recognition. Behavioral data were examined with respect to head-related transfer functions measured using a binaural manikin with and without tested HPDs in place. Data reinforce previous reports that HPDs significantly compromise a variety of auditory perceptual facilities, particularly sound localization due to distortions of high-frequency spectral cues that are important for the avoidance of front-back confusions. © 2015 Brown et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Harrell M.J.,Applied Research Assoc. Inc. | Gillen S.L.,Illinois Tollway | Yaede J.,Applied Research Assoc. Inc.
Transportation Research Record | Year: 2016

In 2005, the Illinois Tollway staff rehabilitated a 33-mi-long segment of Interstate Highway 88 in Illinois by rubblizing deteriorated jointed plain concrete pavement (JPCP) and placing a hot-mix asphalt (HMA) overlay on the rubblized JPCP. The pavement design called for the ultimate pavement structure to be constructed in two stages: the first at the time of rubblization, when at least 6.0 in. of HMA would be placed, and the second 10 years later, when 2.0 in. of HMA would be cold milled and 6.0 in. of HMA placed back. The pavement design called on the tollway staff's experience with rubblization and research surrounding the fatigue endurance limit to develop a staged construction strategy. The strategy would reduce up-front construction costs by placing a minimum of 6.0 in. of HMA at initial construction. The tollway staff was confident that the strategy would work, but the pavement performance was monitored annually for verification. Annual monitoring included pavement distress condition surveys, deflection testing and deflection data analysis, and pavement coring. In particular, the tollway staff desired confirmation that the staged construction strategy would yield a perpetual asphalt pavement by controlling the amount of bottom-up fatigue cracking that would develop in the asphalt mat. After 9 years of observations and data analysis, the staff has confirmed the pavement is exhibiting the properties of a perpetual pavement and the staged construction strategy should ultimately prove successful.


Wang K.,University of North Carolina at Chapel Hill | Stutts C.,Applied Research Assoc. Inc. | Dunn E.,University of North Carolina at Chapel Hill | Frahm J.-M.,University of North Carolina at Chapel Hill
2016 IEEE Winter Conference on Applications of Computer Vision, WACV 2016 | Year: 2016

We propose an efficient algorithm to jointly estimate geometry and semantics for a given geographical region observed by multiple satellite images. Our joint estimation leverages an efficient PatchMatch inference framework defined over lattice discretization of the environment. Our cost function relies on the local planarity assumption to model scene geometry and neural network classification to determine semantic (e.g. land use) labels for geometric structures. By utilizing the commonly available direct (i.e. space to image) rational polynomial coefficients (RPC) satellite camera models, our approach effectively circumvents the need for estimating or refining inverse RPC models. Experiments illustrate both the computational efficiency and high quality scene geometry estimates attained by our approach for satellite imagery. To further illustrate the generality of our representation and inference framework, experiments on standard benchmarks for ground-level imagery are also included. © 2016 IEEE.


Nemeth C.P.,Applied Research Assoc. Inc. | Herrera I.,Sintef
Reliability Engineering and System Safety | Year: 2015

Resilience Engineering (RE) has developed theories, methods, and tools to deliberately manage the adaptive ability of organizations in order to function effectively and safely. As the first peer-reviewed journal publication in the field, this special issue has three purposes: to provide the scientific and industrial communities with the opportunity to present current work in RE, to critically view REs progress and contributions to research and practice, and to pose questions to stimulate thinking about REs future. We propose three values for the RE field of practice: observation, analysis, and design and development. The special issues content and viewpoints are not intended to provide conclusive answers, but rather to stimulate further inquiry and growth. © 2015 Elsevier Ltd. All rights reserved.


Vickery P.J.,Applied Research Assoc. Inc.
Proceedings of the Annual Offshore Technology Conference | Year: 2014

This effort represents a critical examination of the suitability of the models for atmospheric turbulence used in the draft API RP 2MET for describing the characteristics of hurricane winds offshore, using data collected from recent (post-2000) hurricanes. The preliminary results indicate that the current provisions are not suitable for describing hurricane winds, and hence wind loads associated with hurricanes. Using wind speed measurements obtained from Gulf of Mexico hurricanes from a number of sources, the models for mean velocity profiles, gust factors and turbulence intensities given in the draft API RP 2MET were tested against these data. The wind speed data sources include: 1.0 Vertical variation of wind speed with height using NOAA dropwindsonde data 2.0 Gust factor data from NOAA data buoys and C-MAN stations 3.0 Time series of wind speeds from a number of production facilities located in the Gulf of Mexico The investigation found that the provisions of API RP 2MET do not provide a good representation of the structure of the hurricane boundary layer. A major reason that the provisions of API RP 2MET do not model the hurricane boundary layer well is that the models were developed using North Sea data, coupled with an assumption that the surface drag coefficient increases with wind speed. The net result is that at high wind speeds the API RP 2MET relations yield a mean velocity profile that increases too rapidly with height, overestimating wind speeds at typical deck height. For typical design wind speeds for structures located in the Gulf of Mexico the error associated with the API RP 2MET representation of the gust factor varies with height, overestimating the gust factor near the surface (10 m elevation or less), and underestimating it at higher elevations. Copyright 2014, Offshore Technology Conference.


Hein D.K.,Applied Research Assoc. Inc.
T and DI Congress 2014: Planes, Trains, and Automobiles - Proceedings of the 2nd Transportation and Development Institute Congress | Year: 2014

While many agencies responsible for the management of airport infrastructure are working towards holistic infrastructure management, there is currently no standard in place in Canada and the United States. An international standards organization 55000 series of standards is currently under development. This standard uses the British Standards Institute Publicly Available Specification PAS 55 as a foundation for the standard development which is due for completion in late 2013. In 2011, the Transportation Research Board (TRB) Airport Cooperative Research Program (ACRP), sponsored a study to develop a guidebook and primer for airport asset managers in Canada and the United States. This paper, outlines the results of asset management best appropriate practices gleaned from surveys and interviews of over 50 airports of various sizes across North America. The paper outlines a 10 step process for successful asset management implementation and provides details on policy, objectives, strategies and plans for implementing an asset management framework. Specific best practices are described and highlighted along with the keys to their successful implementation. © 2014 American Society of Civil Engineers.


Wilke P.W.,Applied Research Assoc. Inc.
T and DI Congress 2014: Planes, Trains, and Automobiles - Proceedings of the 2nd Transportation and Development Institute Congress | Year: 2014

The Rolling Wheel Deflectometer (RWD) is an innovative device developed for the efficient, high-speed measurement of pavement structural response over a broad network of roads. It uses a series of lasers mounted beneath the bed of a custom-built 16-meter semi-trailer to measure a continuous profile of pavement deflections produced by the trailer's 8,164 kilogram (kg) single axle load. The RWD has recently moved from a research prototype to a production tool that has been used for network level pavement structural evaluation. This paper presents the results of a study that evaluated the structural capacity of 463 kilometers (km) of Pennsylvania Department of Transportation's (PennDOT's) local and arterial roads using the RWD and a Falling Weight Deflectometer (FWD) and comparison of the results to the estimated structural capacity stored in PennDOT's Roadway Management System (RMS). The structural capacity determinations from RWD data were based on a methodology developed by the Asphalt Institute (AI) that correlated deflections from a Benkleman Beam testing device to remaining pavement life. The structural capacity estimates from the FWD were based on conventional techniques described in the 1993 AASHTO Pavement Design Guide. The RMS estimates are based on pavement composition and age data. The results of the study indicated a good correlation between the estimates of remaining pavement life from the three methods, although significant scatter was observed in the data. All three methods clearly distinguished between the structural capacities of three groups of roads with known differences in pavement strength. The study verifies that the RWD is a useful tool for network level pavement evaluation for planning purposes. © 2014 American Society of Civil Engineers.

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