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Aspiration tests in aqueous foam using a breathing simulator

Description: Non-toxic aqueous foams are being developed by Sandia National Laboratories (SNL) for the National Institute of Justice (NIJ) for use in crowd control, cell extractions, and group disturbances in the criminal justice prison systems. The potential for aspiration of aqueous foam during its use and the resulting adverse effects associated with complete immersion in aqueous foam is of major concern to the NIJ when examining the effectiveness and safety of using this technology as a Less-Than-Lethal weapon. This preliminary study was designed to evaluate the maximum quantity of foam that might be aspirated by an individual following total immersion in an SNL-developed aqueous foam. A.T.W. Reed Breathing simulator equipped with a 622 Silverman cam was used to simulate the aspiration of an ammonium laureth sulfate aqueous foam developed by SNL and generated at expansion ratios in the range of 500:1 to 1000:1. Although the natural instinct of an individual immersed in foam is to cover their nose and mouth with a hand or cloth, thus breaking the bubbles and decreasing the potential for aspiration, this study was performed to examine a worst case scenario where mouth breathing only was examined, and no attempt was made to block foam entry into the breathing port. Two breathing rates were examined: one that simulated a sedentary individual with a mean breathing rate of 6.27 breaths/minute, and one that simulated an agitated or heavily breathing individual with a mean breathing rate of 23.7 breaths/minute. The results of this study indicate that, if breathing in aqueous foam without movement, an air pocket forms around the nose and mouth within one minute of immersion.
Date: December 1, 1995
Creator: Archuleta, M.M.
Partner: UNT Libraries Government Documents Department

Measurement of ''closing volume'' as affected by lung volume at tracer bolus inspiration, breath holding, and expiratory flow rate

Description: From international symposium on regional lung function and closing volumes; Malmo, Sweden (14 Sep 1973). The measurement of closing volume is of great interest in the early detection of diseases of the small airways, especially if this technique can be used for mass screening with mobile equipment. The basis undenlying the closing volume measurement involves either the inspiration of a tracer gas bolus, such as radioactive /sup 133/Xe or /sup 13/N or stable argon or helium, followed by measurement of the tracer concentration in the expirate, or analysis of the expirate for nitrogen, following a vital capacity (VC) inspiration of pure oxygen. The point (expired volume) at which the alveolar gas concentration changes discretely from the alveolar plateau, Phase III, to Phase IV is denoted as the closing volume, and is believed to represent the onset of closure of the dependent airways. The mechanisms involved were studied in four healthy young human volunteers following the inhalation of a 1-ml bolus of helium. (CH)
Date: January 1, 1973
Creator: Susskind, H.; Richards, P. & Atkins, H.L.
Partner: UNT Libraries Government Documents Department

Regional Neonatal Associates for cooperative study of platelet-activating factor (PAF). Summary report

Description: Lipid inflammatory mediators are thought to play an important role in the pathogenesis of the respiratory distress syndrome, including neonatal lung injury and bronchopulmonary dysplasia (BPD). One such mediator is platelet-activating factor (PAF), a potent bioactive phospholipid that induces adverse airway, vascular, and microcirculatory responses. To study the role of PAF in neonatal lung disease, we used an {sup 125}I-radioimmunoassay to measure PAF in whole blood and tracheal lavage in very low birthweight infants at 1, 3, 5, 9, 21 and 28 days after birth. PAF was found in the pulmonary lavagate and blood of ventilated infants as early as one day after birth. Lavagate levels of PAF increased with acute injury (pneumothorax, pneumonia) but were not associated with BPD. Our results indicate PAF could be associated with the pathogenesis of BPD. We suggest that as a consequence of the pathophysiologic processes associated with BPD, PAF is released by pulmonary cells. Our preliminary data indicate that low birthweight infants also have lower PAF acetylhydrolase levels in cord blood and tracheal lavagate as compared to adults. Therefore, it is possible the increased levels of PAF in the blood of low birthweight infants might be due to persistent transient increases in PAF alveolar levels coupled with lower blood acetylhydrolase activities and could be important in the development of symptoms associated with BPD. Future plans for this project call for completing the enzymatic study of acetylhydrolase activity in pulmonary lavage of the BPD infants.
Date: November 1, 1992
Creator: Snyder, F.
Partner: UNT Libraries Government Documents Department

Lung cancer risk of low-level exposures to alpha emitters: critical reappraisal and experiments based on a new cytodynamic model

Description: Ecologic U.S. county data suggest negative associations between residential radon exposure and lung cancer mortality (LCM)-inconsistent with clearly positive associations revealed by occupational data on individual miners, but perhaps explained by competing effects of cell killing vs. mutations in alpha-exposed bronchial epithelium. To assess the latter possibility, a biologically based �cytodynamic 2-stage� (CD2) cancer-risk model was fit to combined 1950-54 age- specific person-year data on lung cancer mortality (LCM) in white females of age 40+ y in 2,821 U.S. counties (-90% never-smokers), and in 5 cohorts of underground miners who never smoked. New estimates of household annual average radon exposure in U.S. counties were used, which were found to have a significant negative ecologic association with 1950-54 LCM in U.S. white females, adjusted for age and all subsets of two among 21 socioeconomic, climatic and other factors considered. A good CD2 fit was obtained to the combined residential/miner data, using biologically plausible parameter values. Without further optimization, the fit also predicted independent inverse dose-rate effects shown (for the first time) to occur in nonsmoking miners. Using the same U.S. county-level LCM data, a separate study revealed a positive ecologic association between LCM and bituminous coal use in the U.S., in agreement with epidemiological data on LCM in women in China. The modeling results obtained are consistent with the CD2-based hypothesis that residential radon exposure has a nonlinear U-shaped relation to LCM risk, and that current linear no-threshold extrapolation models substantially overestimate such risk. A U-shaped dose-response corresponds to a CD2-model prediction that alpha radiation kills more premalignant cells than it generates at low exposure levels, but not at higher levels. To test this hypothesis, groups of Japanese medaka (ricefish minnows) were exposed for 10 to 14 weeks to different concentrations of aqueous radon; histological and quantitative-morphometry analysis of proliferative (premalignant) ...
Date: February 20, 1999
Creator: Bogen, K T
Partner: UNT Libraries Government Documents Department

Viscoelastic Model for Lung Parenchyma for Multi-Scale Modeling of Respiratory System, Phase II: Dodecahedral Micro-Model

Description: In the first year of this contractual effort a hypo-elastic constitutive model was developed and shown to have great potential in modeling the elastic response of parenchyma. This model resides at the macroscopic level of the continuum. In this, the second year of our support, an isotropic dodecahedron is employed as an alveolar model. This is a microscopic model for parenchyma. A hopeful outcome is that the linkage between these two scales of modeling will be a source of insight and inspiration that will aid us in the final year's activity: creating a viscoelastic model for parenchyma.
Date: March 1, 2012
Creator: Freed, Alan D.; Einstein, Daniel R.; Carson, James P. & Jacob, Rick E.
Partner: UNT Libraries Government Documents Department

Particulate air pollution and increased mortality: Biological plausibility for causal relationship

Description: Recently, a number of epidemiological studies have concluded that ambient particulate exposure is associated with increased mortality and morbidity at PM concentrations well below those previously thought to affect human health. These studies have been conducted in several different geographical locations and have involved a range of populations. While the consistency of the findings and the presence of an apparent concentration response relationship provide a strong argument for causality, epidemiological studies can only conclude this based upon inference from statistical associations. The biological plausibility of a causal relationship between low concentrations of PM and daily mortality and morbidity rates is neither intuitively obvious nor expected based on past experimental studies on the toxicity of inhaled particles. Chronic toxicity from inhaled, poorly soluble particles has been observed based on the slow accumulation of large lung burdens of particles, not on small daily fluctuations in PM levels. Acute toxicity from inhaled particles is associated mainly with acidic particles and is observed at much higher concentrations than those observed in the epidemiology studies reporting an association between PM concentrations and morbidity/mortality. To approach the difficult problem of determining if the association between PM concentrations and daily morbidity and mortality is biologically plausible and causal, one must consider (1) the chemical and physical characteristics of the particles in the inhaled atmospheres, (2) the characteristics of the morbidity/mortality observed and the people who are affected, and (3) potential mechanisms that might link the two.
Date: February 1, 1995
Creator: Henderson, R.F.
Partner: UNT Libraries Government Documents Department

Virtual Human Project

Description: This paper describes the development of a comprehensive human modeling environment, the Virtual Human, which will be used initially to model the human respiratory system for purposes of predicting pulmonary disease or injury using lung sounds. The details of the computational environment, including the development of a Virtual Human Thorax, a database for storing models, model parameters, and experimental data, and a Virtual Human web interface are outlined. Preliminary progress in developing this environment will be presented. A separate paper at the conference describes the modeling of sound generation using computational fluid dynamics and the modeling of sound propagation in the human respiratory system.
Date: June 12, 2001
Creator: Ward, RD
Partner: UNT Libraries Government Documents Department

Comparison of old and new ICRP models for respiratory tract dosimetry

Description: This paper examines the historical development and application of respiratory tract dosimetry models by the International Commission for Radiological Protection, ICRP, for health protection from inhaled radioactive aerosols. Three different models are discussed, those that were included in ICRP recommendations published in 1960 and 1979, and the new ICRP Publication 66. Basic features of these models are compared and contrasted. These features include model structure, sites and frequencies of particle deposition, processes and rates of clearance of the deposited material from the respiratory tract, and consideration of the parameters involved in these processes and how various factors can influence these parameters. All three models lead to the calculation of absorbed radiation doses with differing degrees of regional and local specificity. These calculations are achieved using different tools ranging from quick hand calculations to sophisticated computerized modeling approaches. A side-by-side review of these models indicates several important trends in respiratory tract dosimetry models, the most obvious of which is the increased complexity of each new model over the past 30+ years. These increases reflect both the increasing size of the knowledge base derived from studies in laboratory animals and in human subjects and the need for models more broadly applicable for both occupational and environmental exposures. It is likely that future research will be directed to those key aspects of the new model having the largest uncertainties. The detailed design of the new model and its associated software provide excellent means of identifying useful research areas and using the resulting new information in organized and productive ways.
Date: December 31, 1993
Creator: Boecker, B.B.
Partner: UNT Libraries Government Documents Department

Pathways and barriers to genetic testing and screening: Molecular genetics meets the high-risk family. Final report

Description: The proliferation of genetic screening and testing is requiring increasing numbers of Americans to integrate genetic knowledge and interventions into their family life and personal experience. This study examines the social processes that occur as families at risk for two of the most common autosomal recessive diseases, sickle cell disease (SC) and cystic fibrosis (CF), encounter genetic testing. Each of these diseases is found primarily in a different ethnic/racial group (CF in Americans of North European descent and SC in Americans of West African descent). This has permitted them to have a certain additional lens on the role of culture in integrating genetic testing into family life and reproductive planning. A third type of genetic disorder, the thalassemias was added to the sample in order to extent the comparative frame and to include other ethnic and racial groups.
Date: November 1, 1998
Creator: Duster, T.
Partner: UNT Libraries Government Documents Department

Indoor air and human health revisited: A recent IAQ symposium

Description: Indoor Air and Human Health Revisited was a speciality symposium examining the scientific underpinnings of sensory and sensitivity effects, allergy and respiratory disease, neurotoxicity and cancer. An organizing committee selected four persons to chain the sessions and invite experts to give state-of-the-art presentations that will be published as a book. A summary of the presentations is made and some critical issues identified.
Date: December 31, 1994
Creator: Gammage, R.B.
Partner: UNT Libraries Government Documents Department

Associations of indoor carbon dioxide concentrations, VOCS, environmental susceptibilities with mucous membrane and lower respiratory sick building syndrome symptoms in the BASE study: Analyses of the 100 building dataset

Description: Using the 100 office-building Building Assessment Survey and Evaluation (BASE) Study dataset, we performed multivariate logistic regression analyses to quantify the associations between indoor minus outdoor CO{sub 2} (dCO{sub 2}) concentrations and mucous membrane (MM) and lower respiratory system (Lresp) Sick Building Syndrome (SBS) symptoms, adjusting for age, sex, smoking status, presence of carpet in workspace, thermal exposure, relative humidity, and a marker for entrained automobile exhaust. Using principal components analysis we identified a number of possible sources of 73 measured volatile organic compounds in the office buildings, and assessed the impact of these VOCs on the probability of presenting the SBS symptoms. Additionally we included analysis adjusting for the risks for predisposition of having SBS symptoms associated with the allergic, asthmatic, and environmentally sensitive subpopulations within the office buildings. Adjusted odds ratios (ORs) for statistically significant, dose-dependant associations (p<0.05) for dry eyes, sore throat, nose/sinus congestion, and wheeze symptoms with 100-ppm increases in dCO{sub 2} ranged from 1.1 to 1.2. These results suggest that increases in the ventilation rates per person among typical office buildings will, on average significantly reduce the prevalence of several SBS symptoms, up to 80%, even when these buildings meet the existing ASHRAE ventilation standards for office buildings. VOC sources were observed to play an role in direct association with mucous membrane and lower respiratory irritation, and possibly to be indirectly involved in indoor chemical reactions with ozone that produce irritating compounds associated with SBS symptoms. O-xylene, possibly emitted from furniture coatings was associated with shortness of breath (OR at the maximum concentration = 8, p < 0.05). The environmental sensitivities of a large subset of the office building population add to the overall risk of SBS symptoms (ORs ranging from 2 to above 11) within the buildings.
Date: October 1, 2002
Creator: Apte, M.G. & Erdmann, C.A.
Partner: UNT Libraries Government Documents Department

Associations of indoor carbon dioxide concentrations and environmental susceptibilities with mucous membrane and lower respiratory building related symptoms in the BASE study: Analyses of the 100 building dataset

Description: Using the US EPA 100 office-building BASE Study dataset, they conducted multivariate logistic regression analyses to quantify the relationship between indoor CO{sub 2} concentrations (dCO{sub 2}) and mucous membrane (MM) and lower respiratory system (LResp) building related symptoms, adjusting for age, sex, smoking status, presence of carpet in workspace, thermal exposure, relative humidity, and a marker for entrained automobile exhaust. In addition, they tested the hypothesis that certain environmentally-mediated health conditions (e.g., allergies and asthma) confer increased susceptibility to building related symptoms within office buildings. Adjusted odds ratios (ORs) for statistically significant, dose-dependent associations (p < 0.05) for dry eyes, sore throat, nose/sinus congestion, and wheeze symptoms with 100 ppm increases in dCO{sub 2} ranged from 1.1 to 1.2. These results suggest that increases in the ventilation rates per person among typical office buildings will, on average, reduce the prevalence of several building related symptoms by up to 70%, even when these buildings meet the existing ASHRAE ventilation standards for office buildings. Building occupants with certain environmentally-mediated health conditions are more likely to experience building related symptoms than those without these conditions (statistically significant ORs ranged from 2 to 11).
Date: September 1, 2003
Creator: Erdmann, Christine A. & Apte, Michael G.
Partner: UNT Libraries Government Documents Department

Viscoelastic Model for Lung Parenchyma for Multi-Scale Modeling of Respiratory System Phase I: Hypo-Elastic Model for CFD Implementation

Description: An isotropic constitutive model for the parenchyma of lung has been derived from the theory of hypo-elasticity. The intent is to use it to represent the mechanical response of this soft tissue in sophisticated, computational, fluid-dynamic models of the lung. This demands that the continuum model be accurate, yet simple and effcient. An objective algorithm for its numeric integration is provided. The response of the model is determined for several boundary-value problems whose experiments are used for material characterization. The effective elastic, bulk, and shear moduli, and Poisson’s ratio, as tangent functions, are also derived. The model is characterized against published experimental data for lung. A bridge between this continuum model and a dodecahedral model of alveolar geometry is investigated, with preliminary findings being reported.
Date: April 14, 2011
Creator: Freed, Alan D. & Einstein, Daniel R.
Partner: UNT Libraries Government Documents Department

The development of a Compton lung densitometer

Description: A field instrument is being developed for the non-invasive determination of absolute lung density using unique Compton backscattering techniques. A system consisting of a monoenergetic gamma-ray beam and a shielded high resolution high-purity-germanium (HPGe) detector in a close-coupled geometry is designed to minimize errors due to multiple scattering and uncontrollable attenuation in the chestwall. Results of studies on system performance with phantoms, the optimization of detectors, and the fabrication of a practical gamma-ray source are presented. 3 refs., 6 figs., 2 tabs.
Date: November 1, 1988
Creator: Loo, B.W.; Goulding, F.S.; Madden, N.W. & Simon, D.S.
Partner: UNT Libraries Government Documents Department

Estimating population health risk from low-level environmental radon

Description: Although incidence of respiratory cancer is directly related to inhalation of radon and radon daughters, the magnitude of the actual risk is uncertain for members of the general population exposed for long periods to low-level concentrations. Currently, any such estimate of the risk must rely on data obtained through previous studies of underground-miner populations. Several methods of risk analysis have resulted from these studies. Since the breathing atmospheres, smoking patterns, and physiology are different between miners and the general public, overestimates of lung cancer risk to the latter may have resulted. Strong evidence exists to support the theory of synergistic action between alpha radiation and other agents, and therefore a modified relative risk model was developed to predict lung cancer risks to the general public. The model considers latent period, observation period, age dependency, and inherent risks from smoking or geographical location. A test of the model showed excellent agreement with results of the study of Czechoslovakian uranium miners, for which the necessary time factors were available. The risk model was also used to predict lung cancer incidence among residents of homes on reclaimed Florida phosphate lands, and results of this analysis indicate that over the space of many years, the increased incidence of lung cancer due to elevated radon levels may be indisgtinguishable from those due to other causes.
Date: January 1, 1980
Creator: Fisher, D.R.
Partner: UNT Libraries Government Documents Department

Automatic detection of alternations in pulmonary venous pressure

Description: Image processing and pattern recognition techniques are useful in radiology to aid in the decision making process involving disease patterns in radiographs. The long range goal of this study is to develop a completely automated computer controlled optical system for early detection and classification of prepulmonary edema. This is achieved from chest x-rays by observing and measuring certain patterns of lung vascularity which enable us to characterize the presence and severity of the disease. The lung vascularity patterns were extracted using the Fraunhofer diffraction pattern sampling unit which samples the Fourier transform and obtains the spatial frequency measurements. A laser is used to illuminate certain zones of the lung, and by passing the image through a thin convex lens the diffraction pattern is produced. This pattern impinges on a sensor composed of 32 annular rings and 32 angular wedges which sample the squared modulus of the diffraction pattern and produces the annular ring and wedge regions of the transform space. It has been shown that with an increase in pulmonary venous pressure there is a redistribution of blood flow in the lungs. This redistribution will affect the number of vessels in the upper zone as compared to the number of vessels in the lower zones of the lung and thus change the ring and wedge signatures. Measurements of the ring and wedge signatures have been made on a number of chest radiographs which had been classified by the Turner method as to the presence and extent of pulmonary edema. The measurements were used to train a linear classifier program, i.e., to calculate coefficients which allow the program to automatically classify new cases. Preliminary results indicate a classification accuracy on the training data of 90 percent.
Date: January 1, 1977
Creator: Strand, T. C.; Turner, A. F.; Meyers, H. I. & Kruger, R. P.
Partner: UNT Libraries Government Documents Department

Consistency of reported health effects of air pollution

Description: Three different studies have considered the relation between various mortality rates and air pollution levels. this paper evaluates the consistency of these studies and finds some evidence of a constant proportional effect on both males and females. Two of the studies indicate a relation between air pollution and total mortality rate but differ in the estimate of the effect by a factor of fifteen. The studies generally find little relation between pollution and lung diseases and lung cancer; they disagree on heart disease and total cancer findings.
Date: unknown
Creator: Finch, S J & Morris, S C
Partner: UNT Libraries Government Documents Department

Ambient air pollution exposure and the incidence of related health effects among racial/ethnic minorities

Description: Differences among racial and ethnic groups in morbidity and mortality rates for diseases, including diseases with environmental causes, have been extensively documented. However, documenting the linkages between environmental contaminants, individual exposures, and disease incidence has been hindered by difficulties in measuring exposure for the population in general and for minority populations in particular. After briefly discussing research findings on associations of common air pollutants with disease incidence, the authors summarize recent studies of radial/ethnic subgroup differences in incidence of these diseases in the US. They then present evidence of both historic and current patterns of disproportionate minority group exposure to air pollution as measured by residence in areas where ambient air quality standards are violated. The current indications of disproportionate potential exposures of minority and low-income populations to air pollutants represent the continuation of a historical trend. The evidence of linkage between disproportionate exposure to air pollution of racial/ethnic minorities and low-income groups and their higher rates of some air pollution-related diseases is largely circumstantial. Differences in disease incidence and mortality rates among racial/ethnic groups are discussed for respiratory diseases, cancers, and lead poisoning. Pollutants of concern include CO, Pb, SO{sub 2}, O{sub 3}, and particulates.
Date: February 1, 1997
Creator: Nieves, L.A. & Wernette, D.R.
Partner: UNT Libraries Government Documents Department

Metropolitan New York in the greenhouse: Air quality and health effects

Description: A variety of potential effects on human health resulting from climate change have been identified in several assessments. According to an international panel{sup 1} they include direct effects of extreme temperatures on cardiovascular deaths, secondary effects due to vector-borne diseases or crop yields, and tertiary effects such as those that might arise from conflicts over freshwater supplies. To this fist we add the secondary effects of increased air pollution, which may result either directly from climate change or indirectly from increased air conditioning loads and the corresponding pollutant emissions from electric utilities. Higher ozone concentrations have been linked to increased ambient temperatures by both theory and observations of monitoring data. A similar association with particulate matter has been limited to observations, thus far. The pollution-heat linkage has been recognized before` but health effects have not been evaluated in terms of predictions of the joint effects of both agents. This paper has been prepared in two sections. First, we discuss the ozone situation with special reference to the Northeast Corridor and New York. In the second section, we present estimates of the health effects of climate change on New York and discuss some mitigation options.
Date: January 1, 1996
Creator: Kleinman, L.I. & Lipfert, F.
Partner: UNT Libraries Government Documents Department