WorldWideScience

Sample records for chemical health modeling

  1. Indoor Air Nuclear, Biological, and Chemical Health Modeling and Assessment System

    Energy Technology Data Exchange (ETDEWEB)

    Stenner, Robert D.; Hadley, Donald L.; Armstrong, Peter R.; Buck, John W.; Hoopes, Bonnie L.; Janus, Michael C.

    2001-03-01

    Indoor air quality effects on human health are of increasing concern to public health agencies and building owners. The prevention and treatment of 'sick building' syndrome and the spread of air-borne diseases in hospitals, for example, are well known priorities. However, increasing attention is being directed to the vulnerability of our public buildings/places, public security and national defense facilities to terrorist attack or the accidental release of air-borne biological pathogens, harmful chemicals, or radioactive contaminants. The Indoor Air Nuclear, Biological, and Chemical Health Modeling and Assessment System (IA-NBC-HMAS) was developed to serve as a health impact analysis tool for use in addressing these concerns. The overall goal was to develop a user-friendly fully functional prototype Health Modeling and Assessment system, which will operate under the PNNL FRAMES system for ease of use and to maximize its integration with other modeling and assessment capabilities accessible within the FRAMES system (e.g., ambient air fate and transport models, water borne fate and transport models, Physiologically Based Pharmacokinetic models, etc.). The prototype IA-NBC-HMAS is designed to serve as a functional Health Modeling and Assessment system that can be easily tailored to meet specific building analysis needs of a customer. The prototype system was developed and tested using an actual building (i.e., the Churchville Building located at the Aberdeen Proving Ground) and release scenario (i.e., the release and measurement of tracer materials within the building) to ensure realism and practicality in the design and development of the prototype system. A user-friendly "demo" accompanies this report to allow the reader the opportunity for a "hands on" review of the prototype system's capability.

  2. CHEMICALS AND REPRODUCTIVE HEALTH

    Directory of Open Access Journals (Sweden)

    Omer Faruk TEKBAS

    2006-02-01

    Full Text Available However a lot of chemicals had been used in our daily life, we have enough knowledge about the effects of only for a small portion of them on reproductive health. Our knowledge had been arisen from epidemiologic and experimental studies. In order to protect ourselves from chemicals in the environment it should be concentrate on experimental studies and the results of them should be carefully studied during epidemiological researches. It would be tried to tell about the main chemicals which had been known as effective on reproductive health on the following review. [TAF Prev Med Bull 2006; 5(1.000: 50-59

  3. Dose-response modeling : Evaluation, application, and development of procedures for benchmark dose analysis in health risk assessment of chemical substances

    OpenAIRE

    Sand, Salomon

    2005-01-01

    In this thesis, dose-response modeling and procedures for benchmark dose (BMD) analysis in health risk assessment of chemical substances have been investigated. The BMD method has been proposed as an alternative to the NOAEL (no-observedadverse- effect-level) approach in health risk assessment of non-genotoxic agents. According to the BMD concept, a dose-response model is fitted to data and the BMD is defined as the dose causing a predetermined change in response. A lowe...

  4. A model for probabilistic health impact assessment of exposure to food chemicals.

    NARCIS (Netherlands)

    van der Voet, H.; van der Heijden, G.W.; Bos, P.M.J.; Bosgra, S.; Boon, P.E.; Muri, S.D.; Bruschweiler, B.J.

    2010-01-01

    A statistical model is presented extending the integrated probabilistic risk assessment (IPRA) model of van der Voet and Slob [van der Voet, H., Slob, W., 2007. Integration of probabilistic exposure assessment and probabilistic hazard characterisation. Risk Analysis, 27, 351-371]. The aim is to char

  5. A model for probabilistic health impact assessment of exposure to food chemicals

    NARCIS (Netherlands)

    Voet, van der H.; Heijden, van der G.W.A.M.; Bos, P.M.J.; Bosgra, S.; Boon, P.E.; Muri, S.D.; Brüschweiler, B.J.

    2009-01-01

    A statistical model is presented extending the integrated probabilistic risk assessment (IPRA) model of van der Voet and Slob [van der Voet, H., Slob, W., 2007. Integration of probabilistic exposure assessment and probabilistic hazard characterisation. Risk Analysis, 27, 351–371]. The aim is to char

  6. Chemical kinetics modeling

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C.K.; Pitz, W.J. [Lawrence Livermore National Laboratory, CA (United States)

    1993-12-01

    This project emphasizes numerical modeling of chemical kinetics of combustion, including applications in both practical combustion systems and in controlled laboratory experiments. Elementary reaction rate parameters are combined into mechanisms which then describe the overall reaction of the fuels being studied. Detailed sensitivity analyses are used to identify those reaction rates and product species distributions to which the results are most sensitive and therefore warrant the greatest attention from other experimental and theoretical research programs. Experimental data from a variety of environments are combined together to validate the reaction mechanisms, including results from laminar flames, shock tubes, flow systems, detonations, and even internal combustion engines.

  7. Reduction of chemical reaction models

    Science.gov (United States)

    Frenklach, Michael

    1991-01-01

    An attempt is made to reconcile the different terminologies pertaining to reduction of chemical reaction models. The approaches considered include global modeling, response modeling, detailed reduction, chemical lumping, and statistical lumping. The advantages and drawbacks of each of these methods are pointed out.

  8. Environmentally-Induced Malignancies: An In Vivo Model to Evaluate the Health Impact of Chemicals in Mixed Waste

    Energy Technology Data Exchange (ETDEWEB)

    Maria Pallavicini

    2001-05-04

    Occupational and environmental exposure to organic ligands, solvents, fuel hydrocarbons, and polychlorinated biphenyls are linked with increased risk of hematologic malignancies. DOE facilities and waste sites in the U.S. are contaminated with mixtures of potentially hazardous chemicals such as metals, organic ligands, solvents, fuel hydrocarbons, polychlorinated biphenyls and radioactive isotopes. A major goal of this project was to establish linkage between chemical/radiation exposure and induction of genomic damage in target populations with the capability to undergo transformation.

  9. Modeling of turbulent chemical reaction

    Science.gov (United States)

    Chen, J.-Y.

    1995-01-01

    Viewgraphs are presented on modeling turbulent reacting flows, regimes of turbulent combustion, regimes of premixed and regimes of non-premixed turbulent combustion, chemical closure models, flamelet model, conditional moment closure (CMC), NO(x) emissions from turbulent H2 jet flames, probability density function (PDF), departures from chemical equilibrium, mixing models for PDF methods, comparison of predicted and measured H2O mass fractions in turbulent nonpremixed jet flames, experimental evidence of preferential diffusion in turbulent jet flames, and computation of turbulent reacting flows.

  10. Development of regionalized multimedia chemical fate models for China

    OpenAIRE

    Zhu, Ying; Jones, Kevin; Sweetman, Andrew; Price, Oliver; Tao, Shu

    2016-01-01

    To balance the economic development with environmental safety and human health, China has released chemicals management legislation for which chemical prioritization and risk assessment are key issues. To support these ambitions two versions of an environmental fate and behaviour model SESAMe (Sino Evaluative Simplebox-MAMI models), have been developed with different resolutions and structures in this thesis. SESAMe is applied to hypothetical chemicals to investigate the influence of environm...

  11. Chemical kinetics and combustion modeling

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The goal of this program is to gain qualitative insight into how pollutants are formed in combustion systems and to develop quantitative mathematical models to predict their formation rates. The approach is an integrated one, combining low-pressure flame experiments, chemical kinetics modeling, theory, and kinetics experiments to gain as clear a picture as possible of the process in question. These efforts are focused on problems involved with the nitrogen chemistry of combustion systems and on the formation of soot and PAH in flames.

  12. Health effects assessment of chemical exposures: ARIES methodology

    Energy Technology Data Exchange (ETDEWEB)

    Sierra, L; Montero, M.; Rabago, I.; Vidania, R.

    1995-07-01

    In this work, we present ARIES* update: a system designed in order to facilitate the human health effects assessment produced by accidental release of toxic chemicals. The first version of ARIES was developed in relation to 82/501/EEC Directive about mayor accidents in the chemical industry. So, the first aim was the support of the effects assessment derived for the chemicals included into this directive. From this establishment, it was considered acute exposures for high concentrations. In this report, we present the actual methodology for considering other type of exposures, such as environmental and occupational. Likewise other versions, the methodology comprises two approaches: quantitative and qualitative assessments. Quantitative assessment incorporates the mathematical algorithms useful to evaluate the effects produced by the most important routes of exposure: inhalation, ingestion, eye contact and skin absorption, in a short, medium and long term. It has been included models that realizes an accurate quantification of doses, effects,... and so on, such as simple approaches when the available information is not enough. Qualitative assessment, designed in order to complement or replace the previous one, is incorporated into an informatics system, developed in Clipper. It executes and displays outstanding and important toxicological information of about 100 chemicals. This information comes from ECDIN (Environmental Chemicals Data and Information Network) database through a collaboration with JRC-ISPRA working group. (Author) 24 refs.

  13. Chemical leasing business models: a contribution to the effective risk management of chemical substances.

    Science.gov (United States)

    Ohl, Cornelia; Moser, Frank

    2007-08-01

    Chemicals indisputably contribute greatly to the well-being of modern societies. Apart from such benefits, however, chemicals often pose serious threats to human health and the environment when improperly handled. Therefore, the European Commission has proposed a regulatory framework for the Registration, Evaluation and Authorization of Chemicals (REACH) that requires companies using chemicals to gather pertinent information on the properties of these substances. In this article, we argue that the crucial aspect of this information management may be the honesty and accuracy of the transfer of relevant knowledge from the producer of a chemical to its user. This may be particularly true if the application of potentially hazardous chemicals is not part of the user's core competency. Against this background, we maintain that the traditional sales concept provides no incentives for transferring this knowledge. The reason is that increased user knowledge of a chemical's properties may raise the efficiency of its application. That is, excessive and unnecessary usage will be eliminated. This, in turn, would lower the amount of chemicals sold and in competitive markets directly decrease profits of the producer. Through the introduction of chemical leasing business models, we attempt to present a strategy to overcome the incentive structure of classical sales models, which is counterproductive for the transfer of knowledge. By introducing two models (a Model A that differs least and a Model B that differs most from traditional sales concepts), we demonstrate that chemical leasing business models are capable of accomplishing the goal of Registration, Evaluation and Authorization of Chemicals: to effectively manage the risk of chemicals by reducing the total quantity of chemicals used, either by a transfer of applicable knowledge from the lessor to the lessee (Model A) or by efficient application of the chemical by the lessor him/herself (Model B).

  14. Health risk assessment for chemical exposures of military interest

    NARCIS (Netherlands)

    Langenberg, J.P.; Polhuijs, M.; Sijbranda, T.

    2016-01-01

    Participation in military operations is accompanied by health hazards resulting from exposure to chemical substances from natural and anthropogenic sources. Historically, focus on toxicological risks has been on the health effects of exposure to chemical warfare agents (CW A). In recent years the aw

  15. Chemical modeling of exoplanet atmospheres

    CERN Document Server

    Venot, Olivia

    2014-01-01

    The past twenty years have revealed the diversity of planets that exist in the Universe. It turned out that most of exoplanets are different from the planets of our Solar System and thus, everything about them needs to be explored. Thanks to current observational technologies, we are able to determine some information about the atmospheric composition, the thermal structure and the dynamics of these exoplanets, but many questions remain still unanswered. To improve our knowledge about exoplanetary systems, more accurate observations are needed and that is why the Exoplanet Characterisation Observatory (EChO) is an essential space mission. Thanks to its large spectral coverage and high spectral resolution, EChO will provide exoplanetary spectra with an unprecedented accuracy, allowing to improve our understanding of exoplanets. In this work, we review what has been done to date concerning the chemical modeling of exoplanet atmospheres and what are the main characteristics of warm exoplanet atmospheres, which a...

  16. Chemical Leasing business models and corporate social responsibility.

    Science.gov (United States)

    Moser, Frank; Jakl, Thomas; Joas, Reihard; Dondi, Francesco

    2014-11-01

    Chemical Leasing is a service-oriented business model that shifts the focus from increasing sales volume of chemicals towards a value-added approach. Recent pilot projects have shown the economic benefits of introducing Chemical Leasing business models in a broad range of sectors. A decade after its introduction, the promotion of Chemical Leasing is still predominantly done by the public sector and international organizations. We show in this paper that awareness-raising activities to disseminate information on this innovative business model mainly focus on the economic benefits. We argue that selling Chemical Leasing business models solely on the grounds of economic and ecological considerations falls short of branding it as a corporate social responsibility initiative, which, for this paper, is defined as a stakeholder-oriented concept that extends beyond the organization's boundaries and is driven by an ethical understanding of the organization's responsibility for the impact of its business activities. For the analysis of Chemical Leasing business models, we introduce two case studies from the water purification and metal degreasing fields, focusing on employees and local communities as two specific stakeholder groups of the company introducing Chemical Leasing. The paper seeks to demonstrate that Chemical Leasing business models can be branded as a corporate social responsibility initiative by outlining the vast potential of Chemical Leasing to improve occupational health and safety and to strengthen the ability of companies to protect the environment from the adverse effects of the chemicals they apply.

  17. Chemical composition and health effects of Tartary buckwheat.

    Science.gov (United States)

    Zhu, Fan

    2016-07-15

    Tartary buckwheat (Fagopyrum tataricum) contains a range of nutrients including bioactive carbohydrates and proteins, polyphenols, phytosterols, vitamins, carotenoids, and minerals. The unique composition of Tartary buckwheat contributes to their various health benefits such as anti-oxidative, anti-cancer, anti-hypertension, anti-diabetic, cholesterol-lowering, and cognition-improving. Compared with the more widely cultivated and utilised common buckwheat (F. esculentum), Tartary buckwheat tends to contain higher amounts of certain bioactive components such as rutin, therefore, showing higher efficiency in preventing/treating various disorders. This review summarises the current knowledge of the chemical composition of Tartary buckwheat, and their bio-functions as studied by both in vitro and in vivo models. Tartary buckwheat can be further developed as a sustainable crop for functional food production to improve human health.

  18. A Chemical Engineer's Perspective on Health and Disease.

    Science.gov (United States)

    Androulakis, Ioannis P

    2014-12-04

    Chemical process systems engineering considers complex supply chains which are coupled networks of dynamically interacting systems. The quest to optimize the supply chain while meeting robustness and flexibility constraints in the face of ever changing environments necessitated the development of theoretical and computational tools for the analysis, synthesis and design of such complex engineered architectures. However, it was realized early on that optimality is a complex characteristic required to achieve proper balance between multiple, often competing, objectives. As we begin to unravel life's intricate complexities, we realize that that living systems share similar structural and dynamic characteristics; hence much can be learned about biological complexity from engineered systems. In this article, we draw analogies between concepts in process systems engineering and conceptual models of health and disease; establish connections between these concepts and physiologic modeling; and describe how these mirror onto the physiological counterparts of engineered systems.

  19. Mathematical Modeling of Chemical Stoichiometry

    Science.gov (United States)

    Croteau, Joshua; Fox, William P.; Varazo, Kristofoland

    2007-01-01

    In beginning chemistry classes, students are taught a variety of techniques for balancing chemical equations. The most common method is inspection. This paper addresses using a system of linear mathematical equations to solve for the stoichiometric coefficients. Many linear algebra books carry the standard balancing of chemical equations as an…

  20. Chemical reactor modeling multiphase reactive flows

    CERN Document Server

    Jakobsen, Hugo A

    2014-01-01

    Chemical Reactor Modeling closes the gap between Chemical Reaction Engineering and Fluid Mechanics.  The second edition consists of two volumes: Volume 1: Fundamentals. Volume 2: Chemical Engineering Applications In volume 1 most of the fundamental theory is presented. A few numerical model simulation application examples are given to elucidate the link between theory and applications. In volume 2 the chemical reactor equipment to be modeled are described. Several engineering models are introduced and discussed. A survey of the frequently used numerical methods, algorithms and schemes is provided. A few practical engineering applications of the modeling tools are presented and discussed. The working principles of several experimental techniques employed in order to get data for model validation are outlined. The monograph is based on lectures regularly taught in the fourth and fifth years graduate courses in transport phenomena and chemical reactor modeling, and in a post graduate course in modern reactor m...

  1. Modeling Microscopic Chemical Sensors in Capillaries

    CERN Document Server

    Hogg, Tad

    2008-01-01

    Nanotechnology-based microscopic robots could provide accurate in vivo measurement of chemicals in the bloodstream for detailed biological research and as an aid to medical treatment. Quantitative performance estimates of such devices require models of how chemicals in the blood diffuse to the devices. This paper models microscopic robots and red blood cells (erythrocytes) in capillaries using realistic distorted cell shapes. The models evaluate two sensing scenarios: robots moving with the cells past a chemical source on the vessel wall, and robots attached to the wall for longer-term chemical monitoring. Using axial symmetric geometry with realistic flow speeds and diffusion coefficients, we compare detection performance with a simpler model that does not include the cells. The average chemical absorption is quantitatively similar in both models, indicating the simpler model is an adequate design guide to sensor performance in capillaries. However, determining the variation in forces and absorption as cells...

  2. Classification of Chemical Substances and Adverse Effects of Chemical Substances on Human Health

    OpenAIRE

    Söyleriz, Yüksel

    2015-01-01

    In this study, classification of chemical substances and adverse effects of chemical substances on human health in European Union and Turkey are assessed. Method In this study, national and international legislation and practices in the countries of the European Union are reviewed.

  3. Coulombic Models in Chemical Bonding.

    Science.gov (United States)

    Sacks, Lawrence J.

    1986-01-01

    Compares the coulumbic point charge model for hydrogen chloride with the valence bond model. It is not possible to assign either a nonpolar or ionic canonical form of the valence bond model, while the covalent-ionic bond distribution does conform to the point charge model. (JM)

  4. Chemical equilibrium modeling of detonation

    Energy Technology Data Exchange (ETDEWEB)

    Fried, Laurence E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bastea, Sorin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2010-05-19

    Energetic materials are unique for having a strong exothermic reactivity, which has made them desirable for both military and commercial applications. Energetic materials are commonly divided into high explosives, propellants, and pyrotechnics. We will focus on high explosive (HE) materials here, although there is a great deal of commonality between the classes of energetic materials. Furthermore the history of HE materials is long, their condensed-phase chemical properties are poorly understood.

  5. Chemical Kinetic Modeling of Biofuel Combustion

    Science.gov (United States)

    Sarathy, Subram Maniam

    Bioalcohols, such as bioethanol and biobutanol, are suitable replacements for gasoline, while biodiesel can replace petroleum diesel. Improving biofuel engine performance requires understanding its fundamental combustion properties and the pathways of combustion. This study's contribution is experimentally validated chemical kinetic combustion mechanisms for biobutanol and biodiesel. Fundamental combustion data and chemical kinetic mechanisms are presented and discussed to improve our understanding of biofuel combustion. The net environmental impact of biobutanol (i.e., n-butanol) has not been studied extensively, so this study first assesses the sustainability of n-butanol derived from corn. The results indicate that technical advances in fuel production are required before commercializing biobutanol. The primary contribution of this research is new experimental data and a novel chemical kinetic mechanism for n-butanol combustion. The results indicate that under the given experimental conditions, n-butanol is consumed primarily via abstraction of hydrogen atoms to produce fuel radical molecules, which subsequently decompose to smaller hydrocarbon and oxygenated species. The hydroxyl moiety in n-butanol results in the direct production of the oxygenated species such as butanal, acetaldehyde, and formaldehyde. The formation of these compounds sequesters carbon from forming soot precursors, but they may introduce other adverse environmental and health effects. Biodiesel is a mixture of long chain fatty acid methyl esters derived from fats and oils. This research study presents high quality experimental data for one large fatty acid methyl ester, methyl decanoate, and models its combustion using an improved skeletal mechanism. The results indicate that methyl decanoate is consumed via abstraction of hydrogen atoms to produce fuel radicals, which ultimately lead to the production of alkenes. The ester moiety in methyl decanoate leads to the formation of low molecular

  6. Health and environmental effects of complex chemical mixtures: proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    The Office of Health and Environmental Research (OHER) of the Department of Energy supports a broad long-term research program on human health and environmental effects from potential exposure to energy-related complex chemical mixtures. The program seeks basic mechanistic data on the effects of complex mixtures at the cellular, molecular, and whole animal levels to aid in predicting human health effects and seeks ecological data on biological and physical transformations in the mixtures, concentrations of the mixtures in various compartments of the environment, and potential routes for human exposure to these mixtures (e.g., food chain). On June 17-18, 1985, OHER held its First Annual Technical Meeting on the Complex Chemical Mixtures Program in Chicago, IL. The primary purpose of the meeting was to enable principal investigators to report the research status and accomplishments of ongoing complex chemical mixture studies supported by OHER. To help focus future research directions round table discussions were conducted.

  7. Error estimation and adaptive chemical transport modeling

    Directory of Open Access Journals (Sweden)

    Malte Braack

    2014-09-01

    Full Text Available We present a numerical method to use several chemical transport models of increasing accuracy and complexity in an adaptive way. In largest parts of the domain, a simplified chemical model may be used, whereas in certain regions a more complex model is needed for accuracy reasons. A mathematically derived error estimator measures the modeling error and provides information where to use more accurate models. The error is measured in terms of output functionals. Therefore, one has to consider adjoint problems which carry sensitivity information. This concept is demonstrated by means of ozone formation and pollution emission.

  8. New Source Model for Chemical Explosions

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaoning [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-03

    With sophisticated inversion scheme, we recover characteristics of SPE explosions such as corner frequency fc and moment M0, which are used to develop a new source model for chemical explosions.

  9. Uptake of chemicals from indoor air: Pathways and health effects

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2016-01-01

    Building occupants are exposed to manufactured chemicals. Exposure in the indoor environment can occur via non-dietary ingestion (e.g. indoor dust), inhalation and dermal absorption including dermal uptake directly from air. The extent of dermal uptake from air has been previously studied...... intake from inhalation. Further experiments have been conducted with nicotine and the results are similar. Some of the SVOCs present indoors may have adverse health effects or are categorized as potential endocrine-disrupting compounds. It has been suggested that the health effects of a chemical may...

  10. Chemical Kinetic Modeling of Advanced Transportation Fuels

    Energy Technology Data Exchange (ETDEWEB)

    PItz, W J; Westbrook, C K; Herbinet, O

    2009-01-20

    Development of detailed chemical kinetic models for advanced petroleum-based and nonpetroleum based fuels is a difficult challenge because of the hundreds to thousands of different components in these fuels and because some of these fuels contain components that have not been considered in the past. It is important to develop detailed chemical kinetic models for these fuels since the models can be put into engine simulation codes used for optimizing engine design for maximum efficiency and minimal pollutant emissions. For example, these chemistry-enabled engine codes can be used to optimize combustion chamber shape and fuel injection timing. They also allow insight into how the composition of advanced petroleum-based and non-petroleum based fuels affect engine performance characteristics. Additionally, chemical kinetic models can be used separately to interpret important in-cylinder experimental data and gain insight into advanced engine combustion processes such as HCCI and lean burn engines. The objectives are: (1) Develop detailed chemical kinetic reaction models for components of advanced petroleum-based and non-petroleum based fuels. These fuels models include components from vegetable-oil-derived biodiesel, oil-sand derived fuel, alcohol fuels and other advanced bio-based and alternative fuels. (2) Develop detailed chemical kinetic reaction models for mixtures of non-petroleum and petroleum-based components to represent real fuels and lead to efficient reduced combustion models needed for engine modeling codes. (3) Characterize the role of fuel composition on efficiency and pollutant emissions from practical automotive engines.

  11. Reduced Chemical Kinetic Model for Titan Entries

    Directory of Open Access Journals (Sweden)

    Romain Savajano

    2011-01-01

    Full Text Available A reduced chemical kinetic model for Titan's atmosphere has been developed. This new model with 18 species and 28 reactions includes the mainfeatures of a more complete scheme, respecting the radiative fluxes. It has been verified against three key elements: a sensitivity analysis, the equilibrium chemical composition using shock tube simulations in CHEMKIN, and the results of computational fluid dynamics (CFDs simulations.

  12. Modelling Chemical Reasoning to Predict Reactions

    OpenAIRE

    Segler, Marwin H. S.; Waller, Mark P.

    2016-01-01

    The ability to reason beyond established knowledge allows Organic Chemists to solve synthetic problems and to invent novel transformations. Here, we propose a model which mimics chemical reasoning and formalises reaction prediction as finding missing links in a knowledge graph. We have constructed a knowledge graph containing 14.4 million molecules and 8.2 million binary reactions, which represents the bulk of all chemical reactions ever published in the scientific literature. Our model outpe...

  13. Public Health Risk Conditioned by Chemical Composition of Ground Water

    Science.gov (United States)

    Yankovich, E.; Osipova, N.; Yankovich, K.; Matveenko, I.

    2016-03-01

    The article studies the public health potential risk originated from water consumption and estimated on the basis of the groundwater chemical composition. We have processed the results of chemical groundwater analysis in different aquifers of Tomsk district (Tomsk Oblast, Russia). More than 8400 samples of chemical groundwater analyses were taken during long-term observation period. Human health risk assessment of exposure to contaminants in drinking water was performed in accordance with the risk assessment guidance for public health concerning chemical pollution of the environment (Russian reference number: 2.1.10.1920-04-M, 2004). Identified potential risks were estimated for consuming water of each aquifer. The comparative analysis of water quality of different aquifers was performed on the basis of the risk coefficient of the total non-carcinogenic effects. The non-carcinogenic risk for the health of the Tomsk district population due to groundwater consumption without prior sanitary treatment was admitted acceptable. A rather similar picture is observed for all aquifers, although deeper aquifers show lower hazard coefficients.

  14. Modeling chlorine dioxide bleaching of chemical pulp

    OpenAIRE

    Tarvo, Ville

    2010-01-01

    This doctoral thesis deals with the phenomenon-based modeling of pulp bleaching. Previous bleaching models typically utilize one or two empirical correlations to predict the kinetics in kappa number development. Empirical correlations are simple to develop, but their parameters are often tied to the validation system. A major benefit of physico-chemical phenomenon models is that they are valid regardless of the reaction environment. Furthermore, modeling the bleaching processes at molecular l...

  15. Chemical Kinetic Models for Advanced Engine Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Pitz, William J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mehl, Marco [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Westbrook, Charles K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-10-22

    The objectives for this project are as follows: Develop detailed chemical kinetic models for fuel components used in surrogate fuels for compression ignition (CI), homogeneous charge compression ignition (HCCI) and reactivity-controlled compression-ignition (RCCI) engines; and Combine component models into surrogate fuel models to represent real transportation fuels. Use them to model low-temperature combustion strategies in HCCI, RCCI, and CI engines that lead to low emissions and high efficiency.

  16. Exposure to Endocrine Disrupting Chemicals and Male Reproductive Health

    Directory of Open Access Journals (Sweden)

    Hueiwang Anna Jeng

    2014-06-01

    Full Text Available Endocrine disrupting chemicals (EDCs can interfere with normal hormonal balance and may exert adverse consequences on humans. The male reproductive system may be susceptible to the effects of such environmental toxicants. This review discusses the recent progress in scientific data mainly from epidemiology studies on the associations between EDCs and male reproductive health and our understanding of possible mechanisms associated with the effects of EDCs on male reproductive health. Finally, the review provides recommendations on future research to enhance our understanding of EDCs and male reproductive health. The review highlights the need for 1 well-defined longitudinal epidemiology studies, with appropriately designed exposure assessment to determine potential causal relationships; 2 chemical and biochemical approaches aimed at a better understanding of the mechanism of action of xenoestrogens with regard to low-dose effects, and assessment of identify genetic susceptibility factors associated with the risk of adverse effects following exposure to EDCs.

  17. Mathematical modeling a chemical engineer's perspective

    CERN Document Server

    Rutherford, Aris

    1999-01-01

    Mathematical modeling is the art and craft of building a system of equations that is both sufficiently complex to do justice to physical reality and sufficiently simple to give real insight into the situation. Mathematical Modeling: A Chemical Engineer's Perspective provides an elementary introduction to the craft by one of the century's most distinguished practitioners.Though the book is written from a chemical engineering viewpoint, the principles and pitfalls are common to all mathematical modeling of physical systems. Seventeen of the author's frequently cited papers are reprinted to illus

  18. Consequence and Resilience Modeling for Chemical Supply Chains

    Science.gov (United States)

    Stamber, Kevin L.; Vugrin, Eric D.; Ehlen, Mark A.; Sun, Amy C.; Warren, Drake E.; Welk, Margaret E.

    2011-01-01

    The U.S. chemical sector produces more than 70,000 chemicals that are essential material inputs to critical infrastructure systems, such as the energy, public health, and food and agriculture sectors. Disruptions to the chemical sector can potentially cascade to other dependent sectors, resulting in serious national consequences. To address this concern, the U.S. Department of Homeland Security (DHS) tasked Sandia National Laboratories to develop a predictive consequence modeling and simulation capability for global chemical supply chains. This paper describes that capability , which includes a dynamic supply chain simulation platform called N_ABLE(tm). The paper also presents results from a case study that simulates the consequences of a Gulf Coast hurricane on selected segments of the U.S. chemical sector. The case study identified consequences that include impacted chemical facilities, cascading impacts to other parts of the chemical sector. and estimates of the lengths of chemical shortages and recovery . Overall. these simulation results can DHS prepare for and respond to actual disruptions.

  19. Communication models in environmental health.

    Science.gov (United States)

    Guidotti, Tee L

    2013-01-01

    Communication models common in environmental health are not well represented in the literature on health communication. Risk communication is a systematic approach to conveying essential information about a specific environmental issue and a framework for thinking about community risk and the alternatives for dealing with it. Crisis communication is intended to provide essential information to people facing an emergency in order to mitigate its effects and to enable them to make appropriate decisions, and it is primarily used in emergency management. Corporate communication is intended to achieve a change in attitude or perception of an organization, and its role in environmental health is usually public relations or to rehabilitate a damaged reputation. Environmental health education is a more didactic approach to science education with respect to health and the environment. Social marketing uses conventional marketing methods to achieve a socially desirable purpose but is more heavily used in health promotion generally. Communication models and styles in environmental health are specialized to serve the needs of the field in communicating with the community. They are highly structured and executed in different ways but have in common a relative lack of emphasis on changing personal or lifestyle behavior compared with health promotion and public health in general and a tendency to emphasize content on specific environmental issues and decision frameworks for protecting oneself or the community through collective action.

  20. Chemical Evolution models of Local Group galaxies

    CERN Document Server

    Tosi, M P

    2003-01-01

    Status quo and perspectives of standard chemical evolution models of Local Group galaxies are summarized, discussing what we have learnt from them, what we know we have not learnt yet, and what I think we will learn in the near future. It is described how Galactic chemical evolution models have helped showing that: i) stringent constraints on primordial nucleosynthesis can be derived from the observed Galactic abundances of the light elements, ii) the Milky Way has been accreting external gas from early epochs to the present time, iii) the vast majority of Galactic halo stars have formed quite rapidly at early epochs. Chemical evolution models for the closest dwarf galaxies, although still uncertain so far, are expected to become extremely reliable in the nearest future, thanks to the quality of new generation photometric and spectroscopic data which are currently being acquired.

  1. Health insurance basic actuarial models

    CERN Document Server

    Pitacco, Ermanno

    2014-01-01

    Health Insurance aims at filling a gap in actuarial literature, attempting to solve the frequent misunderstanding in regards to both the purpose and the contents of health insurance products (and ‘protection products’, more generally) on the one hand, and the relevant actuarial structures on the other. In order to cover the basic principles regarding health insurance techniques, the first few chapters in this book are mainly devoted to the need for health insurance and a description of insurance products in this area (sickness insurance, accident insurance, critical illness covers, income protection, long-term care insurance, health-related benefits as riders to life insurance policies). An introduction to general actuarial and risk-management issues follows. Basic actuarial models are presented for sickness insurance and income protection (i.e. disability annuities). Several numerical examples help the reader understand the main features of pricing and reserving in the health insurance area. A short int...

  2. Radiative transfer modeling of surface chemical deposits

    Science.gov (United States)

    Reichardt, Thomas A.; Kulp, Thomas J.

    2016-05-01

    Remote detection of a surface-bound chemical relies on the recognition of a pattern, or "signature," that is distinct from the background. Such signatures are a function of a chemical's fundamental optical properties, but also depend upon its specific morphology. Importantly, the same chemical can exhibit vastly different signatures depending on the size of particles composing the deposit. We present a parameterized model to account for such morphological effects on surface-deposited chemical signatures. This model leverages computational tools developed within the planetary and atmospheric science communities, beginning with T-matrix and ray-tracing approaches for evaluating the scattering and extinction properties of individual particles based on their size and shape, and the complex refractive index of the material itself. These individual-particle properties then serve as input to the Ambartsumian invariant imbedding solution for the reflectance of a particulate surface composed of these particles. The inputs to the model include parameters associated with a functionalized form of the particle size distribution (PSD) as well as parameters associated with the particle packing density and surface roughness. The model is numerically inverted via Sandia's Dakota package, optimizing agreement between modeled and measured reflectance spectra, which we demonstrate on data acquired on five size-selected silica powders over the 4-16 μm wavelength range. Agreements between modeled and measured reflectance spectra are assessed, while the optimized PSDs resulting from the spectral fitting are then compared to PSD data acquired from independent particle size measurements.

  3. Chemical-reaction model for Mexican wave

    Science.gov (United States)

    Nagatani, Takashi

    2003-05-01

    We present a chemical-reaction model to describe the Mexican wave ( La Ola) in football stadia. The spectator's action is described in terms of chemical reactions. The model is governed by three reaction rates k 1, k 2, and k3. We study the nonlinear waves on one- and two-dimensional lattices. The Mexican wave is formulated as a clockwise forwardly propagating wave. Waves are growing or disappear, depending on the values of reaction rates. In the specific case of k1= k2= k3=1, the nonlinear-wave equation produces a propagating pulse like soliton.

  4. Chemical Kinetic Modeling of 2-Methylhexane Combustion

    KAUST Repository

    Mohamed, Samah Y.

    2015-03-30

    Accurate chemical kinetic combustion models of lightly branched alkanes (e.g., 2-methylalkanes) are important for investigating the combustion behavior of diesel, gasoline, and aviation fuels. Improving the fidelity of existing kinetic models is a necessity, as new experiments and advanced theories show inaccuracy in certain portions of the models. This study focuses on updating thermodynamic data and kinetic model for a gasoline surrogate fuel, 2-methylhexane, with recently published group values and rate rules. These update provides a better agreement with rapid compression machine measurements of ignition delay time, while also strengthening the fundamental basis of the model.

  5. International issues on human health effects of exposure to chemical mixtures.

    Science.gov (United States)

    Feron, Victor J; Cassee, Flemming R; Groten, John P; van Vliet, Petronella W; van Zorge, Job A

    2002-12-01

    In this article, we highlight new developments and recent studies concerning adverse human health effects related to chemical mixtures. One group of activities comprises the development of a new computer program for analyzing mixture studies and a mathematical model as a basis for combination rules that predict the toxicity of mixtures. Other new activities in the area of experimental studies are the application of gene expression technologies in mixture research, and pattern recognition as a tool in safety evaluation of complex mixtures. A "bottom-up" approach for chemosensory detection of mixtures has recently been presented. Other topics include a method for the safety evaluation of natural flavoring complexes, and an evaluation of the possible health effects of the simultaneous intake of food additives. Examples of issues related to mixtures of airborne chemicals are potential interaction of fine particles and gaseous pollutants in ambient air, nasal cancer associated with inhaled chemical mixtures, and the recommendation of a limit value for volatile organic compounds. Topics of a more strategic nature include studies concerning the public health effects of large airports, and the development of criteria for a harmonized classification of chemical mixtures. This overview illustrates that strategies to tackle the safety evaluation of combined exposures and complex mixtures as well as models facilitating the interpretation of findings in the context of risk assessment of mixtures have become increasingly important. It is true that exposure of humans to chemical mixtures is the rule rather than the exception, and therefore health risk assessments should focus on mixtures and not on single chemicals. It is also true, however, that humans have learned to cope with exposure to huge numbers of chemicals simultaneously (food, water, air, soil, and consumer products). Therefore, in view of limited resources for toxicological research, the focus in toxicology should be

  6. Synergistic health effects between chemical pollutants and electromagnetic fields.

    Science.gov (United States)

    Ledoigt, Gérard; Sta, Chaima; Goujon, Eric; Souguir, Dalila; El Ferjani, Ezzeddine

    2015-01-01

    Humans and ecosystems are exposed to highly variable and unknown cocktail of chemicals and radiations. Although individual chemicals are typically present at low concentrations, they can interact with each other resulting in additive or potentially synergistic mixture effects. This was also observed with products obtained by radiation actions such as sunlight or electromagnetic fields that can change the effects of chemicals, such as pesticides, and metal trace elements on health. Concomitant presence of various pesticides and their transformation products adds further complexity to chemical risk assessment since chronic inflammation is a key step for cancer promotion. Degradation of a parent molecule can produce several by-products which can trigger various toxic effects with different impacts on health and environment. For instance, the cocktail of sunlight irradiated sulcotrione pesticide has a greater cytotoxicity and genotoxicity than parent molecule, sulcotrione, and questions about the impact of photochemical process on environment. Adjuvants were shown to modify the biological features of pesticides. Addition of other elements, metals or biological products, can differently enhance cell toxicity of pesticides or electromagnetic radiations suggesting a synergy in living organisms. Electromagnetic fields spreading, pesticide by-products and mixtures monitoring become greater for environmental contamination evaluations.

  7. Chemical Evolution Model of M33

    Science.gov (United States)

    Robles-Valdez, F.; Carigi, L.

    2011-10-01

    We present a chemical evolution model (CEM) of M33 and we find that M33, which is smaller than both M31 and MW, shows a lower gas infall rate, SFR efficiency, and IMF M_{up}. Therefore the CEMs for large spiral galaxies (Carigi et al. 2005; Meneses-Goytia et al. 2011) can be scaled to a smaller galaxy.

  8. Modelling Chemical Reasoning to Predict Reactions

    CERN Document Server

    Segler, Marwin H S

    2016-01-01

    The ability to reason beyond established knowledge allows Organic Chemists to solve synthetic problems and to invent novel transformations. Here, we propose a model which mimics chemical reasoning and formalises reaction prediction as finding missing links in a knowledge graph. We have constructed a knowledge graph containing 14.4 million molecules and 8.2 million binary reactions, which represents the bulk of all chemical reactions ever published in the scientific literature. Our model outperforms a rule-based expert system in the reaction prediction task for 180,000 randomly selected binary reactions. We show that our data-driven model generalises even beyond known reaction types, and is thus capable of effectively (re-) discovering novel transformations (even including transition-metal catalysed reactions). Our model enables computers to infer hypotheses about reactivity and reactions by only considering the intrinsic local structure of the graph, and because each single reaction prediction is typically ac...

  9. Modeling heterogeneous chemical processes on aerosol surface

    Institute of Scientific and Technical Information of China (English)

    Junjun Deng; Tijian Wang; Li Liu; Fei Jiang

    2010-01-01

    To explore the possible impact of heterogeneous chemical processes on atmospheric trace components,a coupled box model including gas-phase chemical processes,aerosol thermodynamic equilibrium processes,and heterogeneous chemical processes on the surface of dust,black carbon(BC)and sea salt is set up to simulate the effects of heterogeneous chemistry on the aerosol surface,and analyze the primary factors affecting the heterogeneous processes.Results indicate that heterogeneous chemical processes on the aerosol surface in the atmosphere will affect the concentrations of trace gases such as H2O2,HO2,O3,NO2,NO3,HNO3 and SO2,and aerosols such as SO42-,NO3-and NH4+.Sensitivity tests suggest that the magnitude of the impact of heterogeneous processes strongly depends on aerosol concentration and the surface uptake coefficients used in the box model.However,the impact of temperature on heterogeneous chemical processes is considerably less.The"renoxification"of HNO3 will affect the components of the troposphere such as nitrogen oxide and ozone.

  10. Models and Modelling Tools for Chemical Product and Process Design

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    2016-01-01

    The design, development and reliability of a chemical product and the process to manufacture it, need to be consistent with the end-use characteristics of the desired product. One of the common ways to match the desired product-process characteristics is through trial and error based experiments......-based framework is that in the design, development and/or manufacturing of a chemical product-process, the knowledge of the applied phenomena together with the product-process design details can be provided with diverse degrees of abstractions and details. This would allow the experimental resources......, are the needed models for such a framework available? Or, are modelling tools that can help to develop the needed models available? Can such a model-based framework provide the needed model-based work-flows matching the requirements of the specific chemical product-process design problems? What types of models...

  11. Multidimensional chemical modelling, II. Irradiated outflow walls

    CERN Document Server

    Bruderer, Simon; Doty, Steven D; van Dishoeck, Ewine F; Bourke, Tyler L

    2009-01-01

    Observations of the high-mass star forming region AFGL 2591 reveal a large abundance of CO+, a molecule known to be enhanced by far UV (FUV) and X-ray irradiation. In chemical models assuming a spherically symmetric envelope, the volume of gas irradiated by protostellar FUV radiation is very small due to the high extinction by dust. The abundance of CO+ is thus underpredicted by orders of magnitude. In a more realistic model, FUV photons can escape through an outflow region and irradiate gas at the border to the envelope. Thus, we introduce the first 2D axi-symmetric chemical model of the envelope of a high-mass star forming region to explain the CO+ observations as a prototypical FUV tracer. The model assumes an axi-symmetric power-law density structure with a cavity due to the outflow. The local FUV flux is calculated by a Monte Carlo radiative transfer code taking scattering on dust into account. A grid of precalculated chemical abundances, introduced in the first part of this series of papers, is used to ...

  12. 75 FR 4402 - Notice of National Conversation on Public Health and Chemical Exposures Leadership Council...

    Science.gov (United States)

    2010-01-27

    ... Health and Chemical Exposures Leadership Council Conference Call Time and Date: 1 p.m.-3 p.m., Friday... National Conversation on Public Health and Chemical Exposures Leadership Council. The National Conversation... protecting the public's health from harmful chemical exposures. The Leadership Council provides...

  13. A grand model for chemical product design

    DEFF Research Database (Denmark)

    Fung, Ka Y.; Ng, Ka M.; Zhang, Lei;

    2016-01-01

    Chemical engineering has been expanding its focus from primarily business-to-business products (B2B) to business-to-consumer (B2C) products. The production of B2B products generally emphasizes on process design and optimization, whereas the production of B2C products focuses on product quality......, ingredients and structure. Market and competitive analysis, government policies and regulations have to be explicitly considered in product design. All these considerations are accounted for in the Grand Product Design Model, which consists of a process model, a property model, a quality model, a cost model...... product composition changes with market conditions. Another is a hand lotion that illustrates how product quality affects the profit.(C) 2016 Elsevier Ltd. All rights reserved....

  14. Impact of environmental chemicals, sociodemographic variables, depression, and clinical indicators of health and nutrition on self-reported health status

    Science.gov (United States)

    Public health researchers ideally integrate social, environmental, and clinical measures to identify predictors of poor health. Chemicals measured in human tissues are often evaluated in relation to intangible or rare health outcomes, or are studied one chemical at a time. Using ...

  15. Thermal, chemical, and mechanical cookoff modeling

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, M.L.; Baer, M.R.; Gross, R.J.

    1994-08-01

    A Thermally Reactive, Elastic-plastic eXplosive code, TREX, has been developed to analyze coupled thermal, chemical and mechanical effects associated with cookoff simulation of confined or unconfined energetic materials. In confined systems, pressure buildup precedes thermal runaway, and unconfined energetic material expands to relieve high stress. The model was developed based on nucleation, decomposition chemistry, and elastic/plastic mechanical behavior of a material with a distribution of internal defects represented as clusters of spherical inclusions. A local force balance, with mass continuity constraints, forms the basis of the model requiring input of temperature and reacted gas fraction. This constitutive material model has been incorporated into a quasistatic mechanics code SANTOS as a material module which predicts stress history associated with a given strain history. The thermal-chemical solver XCHEM has been coupled to SANTOS to provide temperature and reacted gas fraction. Predicted spatial history variables include temperature, chemical species, solid/gas pressure, solid/gas density, local yield stress, and gas volume fraction. One-Dimensional Time to explosion (ODTX) experiments for TATB and PBX 9404 (HMX and NC) are simulated using global multistep kinetic mechanisms and the reactive elastic-plastic constitutive model. Pressure explosions, rather than thermal runaway, result in modeling slow cookoff experiments of confined conventional energetic materials such as TATB. For PBX 9404, pressure explosions also occur at fast cookoff conditions because of low temperature reactions of nitrocellulose resulting in substantial pressurization. A demonstrative calculation is also presented for reactive heat flow in a hollow, propellant-filled, stainless steel cylinder, representing a rocket motor. This example simulation show

  16. Chemically amplified resist modeling in OPC

    Science.gov (United States)

    Zheng, Xin; Huang, Jason; Kuo, Fred; Kazarian, Aram; Chin, Fook; Fan, Yongfa

    2009-03-01

    The mechanism of chemically amplified resist plays a critical role in the modeling of the latent image. To achieve a practical model which can fit into the time frame of OPC, some simplifications and assumptions have to be made. We introduced regression kernels that take into account best exposure focus difference between isotropic pitch, dense, and line end features for the evaluation of image intensity. It compares the image intensity (signal) over small changes above and/or below the regressed "nominal" image position, which in principle corresponds to evaluating the intensity signal at various depths of a fixed resist profile thus can also be regressed for optimization during model development. Our calibration has shown that the model brought a great improvement in prediction for difficult structures such as dense features at or near the optical resolution limit and 2-dimensional features, which are the limiter of the overall model fitting accuracy for 45nm node and below. By replacing other existing techniques, total number of output kernels used for OPC operation is actually reduced with improvement of model accuracy. This model is proven to be a very effective yet accurate addition to the current OPC technology.

  17. ACE-Asia Chemical Transport Modeling Overview

    Science.gov (United States)

    UNO, I.; Chin, M.; Collins, W.; Ginoux, P.; Rasch, P.; Carmichael, G. R.; Yienger, J. J.

    2001-12-01

    ACE-Asia (Asia Pacific Regional Aerosol Characterization Experiment) was designed to increase our understanding of how atmospheric aerosol particles affect the Earth?s climate system. The intensive observation period was carried out during March to May, 2001, and more than 100 researchers from several countries (United States, Japan, Korea, China, and many other Asian countries) participated using aircraft, a research vessel, surface stations and numerical models. Aerosol transport forecast activities played an important role during the ACE-Asia intensive observation period. Three independent modeling groups operated chemical transport models in forecast mode and participated in flight planning activities at the operations center. These models were: MATCH (Model of Atmospheric Transport and Chemistry; Rasch and Collins); GOCART (Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport model; Chin and Ginour) and CFORS (Research Institute for Applied Mechanics, Kyushu University + University of Iowa - Chemical weather FORecast System; Uno, Carmichael and Yienger). The MATCH model used in ACE-Asia was a transport model applied for the Asia region, driven by NCEP forecast meteorology. A unique feature of this model was that it assimilated satellite derived optical depths into its forecast algorithm. The GOCART model provided global aerosol forecast using forecast meteorological fields provided by the Goddard Earth Observing System Data Assimilation System (GEOS DAS). The CFORS model provided regional forecasts using a limited area transport model coupled with Regional Meteorological Modeling System (RAMS), initialized by NCEP and JMA forecasts. All models produced 3-d aerosol forecast products consisting of aerosol mass distributions and optical depths for sulfate, black carbon, organic carbon, sea salt, and dust. In the field these model products were made available to all participating scientists via the Web, and were also presented during the

  18. Pool chemical-associated health events in public and residential settings - United States, 2003-2012, and Minnesota, 2013.

    Science.gov (United States)

    Hlavsa, Michele C; Robinson, Trisha J; Collier, Sarah A; Beach, Michael J

    2014-05-16

    Pool chemicals are added to treated recreational water venues (e.g., pools, hot tubs/spas, and interactive fountains) primarily to protect public health by inactivating pathogens and maximizing the effectiveness of disinfection by controlling pH. However, pool chemicals also can cause injuries when handled or stored improperly. To estimate the number of emergency department (ED) visits for injuries associated with pool chemicals in the United States per year during 2003-2012, CDC analyzed data from the U.S. Consumer Product Safety Commission's National Electronic Injury Surveillance System (NEISS). This report summarizes the results of that analysis. In 2012 alone, an estimated 4,876 persons (95% confidence interval [CI] = 2,821-6,930) visited an ED for injuries associated with pool chemicals. Almost half of the patients were aged pool chemical-associated health event that occurred in Minnesota in 2013, which sent seven children and one adult to an ED. An investigation by the Minnesota Department of Health (MDH) determined the cause to be poor monitoring of or response to pool chemistry. Pool chemical-associated health events are preventable. CDC's Model Aquatic Health Code (MAHC) (1) is a resource that state and local agencies can use to optimize prevention of injuries and illnesses associated with public treated recreational water venues, including pool chemical-associated health events.

  19. Status of dental health in chemical warfare victims: The case of Isfahan, Iran

    Directory of Open Access Journals (Sweden)

    Ahmad Mottaghi

    2012-01-01

    Conclusion: Chemical warfare victims have relatively poor dental/oral health. Chemical injury might cause a dysfunction in saliva secretion, with decrease in saliva secretion increasing the risk for tooth decay and periodontal disorders. Further research is required to find out the exact underlying mechanisms and the factors associated with poor dental/oral health in chemical warfare victims.

  20. Chemically induced mouse models of intestinal inflammation.

    Science.gov (United States)

    Wirtz, Stefan; Neufert, Clemens; Weigmann, Benno; Neurath, Markus F

    2007-01-01

    Animal models of intestinal inflammation are indispensable for our understanding of the pathogenesis of Crohn disease and ulcerative colitis, the two major forms of inflammatory bowel disease in humans. Here, we provide protocols for establishing murine 2,4,6-trinitro benzene sulfonic acid (TNBS)-, oxazolone- and both acute and chronic dextran sodium sulfate (DSS) colitis, the most widely used chemically induced models of intestinal inflammation. In the former two models, colitis is induced by intrarectal administration of the covalently reactive reagents TNBS/oxazolone, which are believed to induce a T-cell-mediated response against hapten-modified autologous proteins/luminal antigens. In the DSS model, mice are subjected several days to drinking water supplemented with DSS, which seems to be directly toxic to colonic epithelial cells of the basal crypts. The procedures for the hapten models of colitis and acute DSS colitis can be accomplished in about 2 weeks but the protocol for chronic DSS colitis takes about 2 months.

  1. Navigating public health chemicals policy in Australia: a policy maker's and practitioner's guide.

    Science.gov (United States)

    Capon, Adam; Smith, Wayne; Gillespie, James A

    2013-03-01

    Chemicals are ubiquitous in everyday life. Environmental health practitioners rely on a complex web of regulators and policy bodies to ensure the protection of public health, yet few understand the full extent of this web. A lack of understanding can hamper public health response and impede policy development. In this paper we map the public health chemicals policy landscape in Australia and conclude that an understanding of this system is essential for effective environmental health responses and policy development.

  2. Cleaner combustion developing detailed chemical kinetic models

    CERN Document Server

    Battin-Leclerc, Frédérique; Blurock, Edward

    2013-01-01

    This overview compiles the on-going research in Europe to enlarge and deepen the understanding of the reaction mechanisms and pathways associated with the combustion of an increased range of fuels. Focus is given to the formation of a large number of hazardous minor pollutants and the inability of current combustion models to predict the  formation of minor products such as alkenes, dienes, aromatics, aldehydes and soot nano-particles which have a deleterious impact on both the environment and on human health. Cleaner Combustion describes, at a fundamental level, the reactive chemistry of min

  3. Chemicals in the air of the work environment and health risks

    Directory of Open Access Journals (Sweden)

    Karin reinhold

    2010-07-01

    Full Text Available The study focuses on indoor air quality (microclimate andchemicals in industrial premises. The health risk is determined.The model is presented for taking into consideration theconcentration of chemicals in the air of the work environment andpossible negative health effects. Practical examples and the resultsof measurements of microclimate and chemicals concentration inthe workplace air in five industries (mechanical, printing, wood,plastic and clothing industries are presented. The microclimate isunder control except during very hot climate in summer. Thechemicals are under control in printing, mechanical (exceptwelding in closed workrooms, and clothing industry. Thechemicals are often over the limits in wood processing industryand in some of the premises of plastic (manufacturing of rubberdetails industry.

  4. Application of Health Promotion Theories and Models for Environmental Health

    Science.gov (United States)

    Parker, Edith A.; Baldwin, Grant T.; Israel, Barbara; Salinas, Maria A.

    2004-01-01

    The field of environmental health promotion gained new prominence in recent years as awareness of physical environmental stressors and exposures increased in communities across the country and the world. Although many theories and conceptual models are used routinely to guide health promotion and health education interventions, they are rarely…

  5. Epigenome: A Biomarker or Screening Tool to Evaluate Health Impact of Cumulative Exposure to Chemical and Non-Chemical Stressors.

    Science.gov (United States)

    Olden, Kenneth; Lin, Yu-Sheng; Bussard, David

    2016-06-01

    Current risk assessment practices and toxicity information are hard to utilize for assessing the health impact of combined or cumulative exposure to multiple chemical and non-chemical stressors encountered in the "real world" environment. Non-chemical stressors such as heat, radiation, noise, humidity, bacterial and viral agents, and social factors, like stress related to violence and socioeconomic position generally cannot be currently incorporated into the risk assessment paradigm. The Science and Decisions report released by the National Research Council (NRC) in 2009 emphasized the need to characterize the effects of multiple stressors, both chemical and non-chemical exposures. One impediment to developing information relating such non-chemical stressors to health effects and incorporating them into cumulative assessment has been the lack of analytical tools to easily and quantitatively monitor the cumulative exposure to combined effects of stressors over the life course.

  6. The Impact of Modeling Assumptions in Galactic Chemical Evolution Models

    CERN Document Server

    Côté, Benoit; Ritter, Christian; Herwig, Falk; Venn, Kim A

    2016-01-01

    We use the OMEGA galactic chemical evolution code to investigate how the assumptions used for the treatment of galactic inflows and outflows impact numerical predictions. The goal is to determine how our capacity to reproduce the chemical evolution trends of a galaxy is affected by the choice of implementation used to include those physical processes. In pursuit of this goal, we experiment with three different prescriptions for galactic inflows and outflows and use OMEGA within a Markov Chain Monte Carlo code to recover the set of input parameters that best reproduces the chemical evolution of nine elements in the dwarf spheroidal galaxy Sculptor. Despite their different degrees of intended physical realism, we found that all three prescriptions can reproduce in an almost identical way the stellar abundance trends observed in Sculptor. While the three models have the same capacity to fit the data, the best values recovered for the parameters controlling the number of Type Ia supernovae and the strength of gal...

  7. THE USE OF CHEMICALS IN THE FIELD OF FARM ANIMAL HEALTH (NUTRITION, ENTOMOLOGY, PATHOLOGY). AGRICULTURAL CHEMICALS TECHNOLOGY, NUMBER 7.

    Science.gov (United States)

    Ohio State Univ., Columbus. Center for Vocational and Technical Education.

    DEVELOPED BY A NATIONAL TASK FORCE ON THE BASIS OF STATE STUDIES, THIS MODULE IS ONE OF A SERIES DESIGNED TO ASSIST TEACHERS IN PREPARING POST-SECONDARY STUDENTS FOR AGRICULTURAL CHEMICAL OCCUPATIONS. THE SPECIFIC OBJECTIVE OF THIS MODULE IS TO PREPARE TECHNICIANS IN THE FIELD OF THE USE OF CHEMICALS FOR ANIMAL HEALTH. SECTIONS INCLUDE -- (1)…

  8. Pender's health promotion model in medical research.

    Science.gov (United States)

    Heydari, Abbas; Khorashadizadeh, Fatemeh

    2014-09-01

    This review shows how researchers use pander's health promotion model. We included all articles in which Pender's health promotion has been used for theoretical framework. Eligible articles were selected according to review of abstracts. Search was conducted using the electronic database from 1990 to 2012. Based on our search, 74 articles with various methodologies were relevant for review. Their aims of these studies were to predict effective factors/barriers in health promotion behaviours, to detect effects of intervention programme for improving health promotion behaviours, test the model, identify quality of life and health promotion behaviour, predict stage of change in related factors that affect health promotion behaviour, prevent the events that interfere with health promotion behaviour, develop another model similar to this model, compare this model with another model, determine the relationship of variables associated to health promotion behaviours.

  9. A kinetic model for chemical neurotransmission

    Science.gov (United States)

    Ramirez-Santiago, Guillermo; Martinez-Valencia, Alejandro; Fernandez de Miguel, Francisco

    Recent experimental observations in presynaptic terminals at the neuromuscular junction indicate that there are stereotyped patterns of cooperativeness in the fusion of adjacent vesicles. That is, a vesicle in hemifusion process appears on the side of a fused vesicle and which is followed by another vesicle in a priming state while the next one is in a docking state. In this talk we present a kinetic model for this morphological pattern in which each vesicle state previous to the exocytosis is represented by a kinetic state. This chain states kinetic model can be analyzed by means of a Master equation whose solution is simulated with the stochastic Gillespie algorithm. With this approach we have reproduced the responses to the basal release in the absence of stimulation evoked by the electrical activity and the phenomena of facilitation and depression of neuromuscular synapses. This model offers new perspectives to understand the underlying phenomena in chemical neurotransmission based on molecular interactions that result in the cooperativity between vesicles during neurotransmitter release. DGAPA Grants IN118410 and IN200914 and Conacyt Grant 130031.

  10. Chemical Mechanism Solvers in Air Quality Models

    Directory of Open Access Journals (Sweden)

    John C. Linford

    2011-09-01

    Full Text Available The solution of chemical kinetics is one of the most computationally intensivetasks in atmospheric chemical transport simulations. Due to the stiff nature of the system,implicit time stepping algorithms which repeatedly solve linear systems of equations arenecessary. This paper reviews the issues and challenges associated with the construction ofefficient chemical solvers, discusses several families of algorithms, presents strategies forincreasing computational efficiency, and gives insight into implementing chemical solverson accelerated computer architectures.

  11. A mesoscale chemical transport model (MEDIUM) nested in a global chemical transport model (MEDIANTE)

    Energy Technology Data Exchange (ETDEWEB)

    Claveau, J.; Ramaroson, R. [Office National d`Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France)

    1997-12-31

    The lower stratosphere and upper troposphere (UT-LS) are frequently subject to mesoscale or local scale exchange of air masses occurring along discontinuities. This exchange (e.g. downward) can constitute one of the most important source of ozone from the stratosphere down to the middle troposphere where strong mixing dilutes the air mass and competing the non-linear chemistry. The distribution of the chemical species in the troposphere and the lower stratosphere depends upon various source emissions, e.g. from polluted boundary layer or from aircraft emissions. Global models, as well as chemical transport models describe the climatological state of the atmosphere and are not able to describe correctly the stratosphere and troposphere exchange. Mesoscale models go further in the description of smaller scales and can reasonably include a rather detailed chemistry. They can be used to assess the budget of NO{sub x} from aircraft emissions in a mesoscale domain. (author) 4 refs.

  12. The Impact of Modeling Assumptions in Galactic Chemical Evolution Models

    Science.gov (United States)

    Côté, Benoit; O’Shea, Brian W.; Ritter, Christian; Herwig, Falk; Venn, Kim A.

    2017-02-01

    We use the OMEGA galactic chemical evolution code to investigate how the assumptions used for the treatment of galactic inflows and outflows impact numerical predictions. The goal is to determine how our capacity to reproduce the chemical evolution trends of a galaxy is affected by the choice of implementation used to include those physical processes. In pursuit of this goal, we experiment with three different prescriptions for galactic inflows and outflows and use OMEGA within a Markov Chain Monte Carlo code to recover the set of input parameters that best reproduces the chemical evolution of nine elements in the dwarf spheroidal galaxy Sculptor. This provides a consistent framework for comparing the best-fit solutions generated by our different models. Despite their different degrees of intended physical realism, we found that all three prescriptions can reproduce in an almost identical way the stellar abundance trends observed in Sculptor. This result supports the similar conclusions originally claimed by Romano & Starkenburg for Sculptor. While the three models have the same capacity to fit the data, the best values recovered for the parameters controlling the number of SNe Ia and the strength of galactic outflows, are substantially different and in fact mutually exclusive from one model to another. For the purpose of understanding how a galaxy evolves, we conclude that only reproducing the evolution of a limited number of elements is insufficient and can lead to misleading conclusions. More elements or additional constraints such as the Galaxy’s star-formation efficiency and the gas fraction are needed in order to break the degeneracy between the different modeling assumptions. Our results show that the successes and failures of chemical evolution models are predominantly driven by the input stellar yields, rather than by the complexity of the Galaxy model itself. Simple models such as OMEGA are therefore sufficient to test and validate stellar yields. OMEGA

  13. In situ models, physico-chemical aspects.

    Science.gov (United States)

    ten Cate, J M

    1994-07-01

    In situ (intra-oral) caries models are used for two purposes. First, they provide information about oral physiological processes. Such information helps to detail our knowledge of the oral ecosystem and to verify conclusions from in vitro experiments. Second, in situ models are utilized to test preventive agents in the phase between laboratory testing and clinical trials. Most investigations involving enamel inserts have been aimed at testing new dentifrices. The experimental designs of such studies usually do not allow one to draw conclusions on physico-chemical processes, e.g., because of single point measurements. Studies of model parameters (lesion type, lesion severity, and de/remineralization in time) constitute only a minority of the research reports. The most striking observation obtained with in situ models has been the significant differences in de/remineralization observed among individuals and, more importantly, within one individual during different time periods and between different sites in the same mouth (for review, see ten Cate et al., 1992). Regardless of this, some general findings can be inferred: During in situ demineralization, up to 62 vol% microns/day may be removed from enamel. For dentin specimens, this value may be as high as 89 vol% microns/day. For remineralization, during fluoride dentifrice treatment, a median deposition rate of 0.7%/day (for lesions with integrated mineral loss values between 2000 and 4000 vol% microns) is found. The rate of deposition seems to be correlated with the extent of the pre-formed lesion. This suggests that the number of sites (crystallite surface) available for calcium phosphate precipitation is an important parameter.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Comparative dynamics in a health investment model.

    Science.gov (United States)

    Eisenring, C

    1999-10-01

    The method of comparative dynamics fully exploits the inter-temporal structure of optimal control models. I derive comparative dynamic results in a simplified demand for health model. The effect of a change in the depreciation rate on the optimal paths for health capital and investment in health is studied by use of a phase diagram.

  15. A generalized physiologically-based toxicokinetic modeling system for chemical mixtures containing metals

    Directory of Open Access Journals (Sweden)

    Isukapalli Sastry S

    2010-06-01

    -to-dose-to-effect" framework for modeling population health risks from environmental contaminants. As new data become available on interactions of multiple chemicals, the GTMM can be iteratively parameterized to improve mechanistic understanding of human health risks from exposures to complex mixtures of chemicals.

  16. Modeling Complex Chemical Systems: Problems and Solutions

    Science.gov (United States)

    van Dijk, Jan

    2016-09-01

    Non-equilibrium plasmas in complex gas mixtures are at the heart of numerous contemporary technologies. They typically contain dozens to hundreds of species, involved in hundreds to thousands of reactions. Chemists and physicists have always been interested in what are now called chemical reduction techniques (CRT's). The idea of such CRT's is that they reduce the number of species that need to be considered explicitly without compromising the validity of the model. This is usually achieved on the basis of an analysis of the reaction time scales of the system under study, which identifies species that are in partial equilibrium after a given time span. The first such CRT that has been widely used in plasma physics was developed in the 1960's and resulted in the concept of effective ionization and recombination rates. It was later generalized to systems in which multiple levels are effected by transport. In recent years there has been a renewed interest in tools for chemical reduction and reaction pathway analysis. An example of the latter is the PumpKin tool. Another trend is that techniques that have previously been developed in other fields of science are adapted as to be able to handle the plasma state of matter. Examples are the Intrinsic Low Dimension Manifold (ILDM) method and its derivatives, which originate from combustion engineering, and the general-purpose Principle Component Analysis (PCA) technique. In this contribution we will provide an overview of the most common reduction techniques, then critically assess the pros and cons of the methods that have gained most popularity in recent years. Examples will be provided for plasmas in argon and carbon dioxide.

  17. Modeling Per Capita State Health Expenditure Variat...

    Data.gov (United States)

    U.S. Department of Health & Human Services — Modeling Per Capita State Health Expenditure Variation State-Level Characteristics Matter, published in Volume 3, Issue 4, of the Medicare and Medicaid Research...

  18. Addressing Human Variability in Next-Generation Human Health Risk Assessments of Environmental Chemicals

    Science.gov (United States)

    Bois, Frederic Y.; Chiu, Weihsueh A.; Hattis, Dale; Rusyn, Ivan; Guyton, Kathryn Z.

    2012-01-01

    Background: Characterizing variability in the extent and nature of responses to environmental exposures is a critical aspect of human health risk assessment. Objective: Our goal was to explore how next-generation human health risk assessments may better characterize variability in the context of the conceptual framework for the source-to-outcome continuum. Methods: This review was informed by a National Research Council workshop titled “Biological Factors that Underlie Individual Susceptibility to Environmental Stressors and Their Implications for Decision-Making.” We considered current experimental and in silico approaches, and emerging data streams (such as genetically defined human cells lines, genetically diverse rodent models, human omic profiling, and genome-wide association studies) that are providing new types of information and models relevant for assessing interindividual variability for application to human health risk assessments of environmental chemicals. Discussion: One challenge for characterizing variability is the wide range of sources of inherent biological variability (e.g., genetic and epigenetic variants) among individuals. A second challenge is that each particular pair of health outcomes and chemical exposures involves combinations of these sources, which may be further compounded by extrinsic factors (e.g., diet, psychosocial stressors, other exogenous chemical exposures). A third challenge is that different decision contexts present distinct needs regarding the identification—and extent of characterization—of interindividual variability in the human population. Conclusions: Despite these inherent challenges, opportunities exist to incorporate evidence from emerging data streams for addressing interindividual variability in a range of decision-making contexts. PMID:23086705

  19. GREENSCOPE: A Method for Modeling Chemical Process ...

    Science.gov (United States)

    Current work within the U.S. Environmental Protection Agency’s National Risk Management Research Laboratory is focused on the development of a method for modeling chemical process sustainability. The GREENSCOPE methodology, defined for the four bases of Environment, Economics, Efficiency, and Energy, can evaluate processes with over a hundred different indicators. These indicators provide a means for realizing the principles of green chemistry and green engineering in the context of sustainability. Development of the methodology has centered around three focal points. One is a taxonomy of impacts that describe the indicators and provide absolute scales for their evaluation. The setting of best and worst limits for the indicators allows the user to know the status of the process under study in relation to understood values. Thus, existing or imagined processes can be evaluated according to their relative indicator scores, and process modifications can strive towards realizable targets. A second area of focus is in advancing definitions of data needs for the many indicators of the taxonomy. Each of the indicators has specific data that is necessary for their calculation. Values needed and data sources have been identified. These needs can be mapped according to the information source (e.g., input stream, output stream, external data, etc.) for each of the bases. The user can visualize data-indicator relationships on the way to choosing selected ones for evalua

  20. Multidimensional thermal-chemical cookoff modeling

    Energy Technology Data Exchange (ETDEWEB)

    Baer, M.R.; Gross, R.J.; Gartling, D.K.; Hobbs, M.L.

    1994-08-01

    Multidimensional thermal/chemical modeling is an essential step in the development of a predictive capability for cookoff of energetic materials in systems subjected to abnormal thermal environments. COYOTE II is a state-of-the-art two- and three-dimensional finite element code for the solution of heat conduction problems including surface-to-surface thermal radiation heat transfer and decomposition chemistry. Multistep finite rate chemistry is incorporated into COYOTE II using an operator-splitting methodology; rate equations are solved element-by-element with a modified matrix-free stiff solver, CHEMEQ. COYOTE II is purposely designed with a user-oriented input structure compatible with the database, the pre-processing mesh generation, and the post-processing tools for data visualization shared with other engineering analysis codes available at Sandia National Laboratories. As demonstrated in a companion paper, decomposition during cookoff in a confined or semi-confined system leads to significant mechanical behavior. Although mechanical effect are not presently considered in COYOTE II, the formalism for including mechanics in multidimensions is under development.

  1. Health behaviors of people with hypertension: health belief model

    OpenAIRE

    Ariane Alves Barros; Maria Vilaní Cavalcante Guedes; Denizielle de Jesus Moreira Moura; Luciana Catunda Gomes de Menezes; Letícia Lima Aguiar; Gleudson Alves Xavier

    2014-01-01

    This study aimed to identify the lifestyle of hypertensive patients, focusing on their health behaviors in light of the Health Belief Model. This is a descriptive cross-sectional study with a sample of 133 patients over 18 years old, with hypertension, registered in the Clinical Management System for Hypertension and Diabetes Mellitus in Primary Care, and monitored in five health centers in Fortaleza, CE, Brazil, chosen randomly and probabilistically. Data collection happened through a struct...

  2. The chemical transport model Oslo CTM3

    Directory of Open Access Journals (Sweden)

    O. A. Søvde

    2012-06-01

    Full Text Available We present here the global chemical transport model Oslo CTM3, an update of the Oslo CTM2. The update comprises a faster transport scheme, an improved wet scavenging scheme for large scale rain, updated photolysis rates and a new lightning parameterization. Oslo CTM3 is better parallelized and allows for stable, large time steps for advection, enabling more complex or high resolution simulations. Thorough comparisons between the Oslo CTM3, Oslo CTM2 and measurements are performed, and in general the Oslo CTM3 is found to reproduce measurements well. Inclusion of tropospheric sulfur chemistry and nitrate aerosols in CTM3 is shown to be important to reproduce tropospheric O3, OH and the CH4 lifetime well. Using the same meteorology to drive the two models, shows that some features related to transport are better resolved by the CTM3, such as polar cap transport, while features like transport close to the vortex edge are resolved better in the Oslo CTM2 due to its required shorter transport time step. The longer transport time steps in CTM3 result in larger errors e.g. near the jets, and when necessary, this can be remedied by using a shorter time step. An additional, more accurate and time consuming, treatment of polar cap transport is presented, however, both perform acceptably. A new treatment of the horizontal distribution of lightning is presented and found to compare well with measurements. Vertical distributions of lighting are updated, and tested against the old vertical distribution. The new profiles are found to produce more NOx in the tropical middle troposphere, and less at the surface and at high altitudes.

  3. Modeling release of chemicals from multilayer materials into food

    Directory of Open Access Journals (Sweden)

    Huang Xiu-Ling

    2016-01-01

    Full Text Available The migration of chemicals from materials into food is predictable by various mathematical models. In this article, a general mathematical model is developed to quantify the release of chemicals through multilayer packaging films based on Fick's diffusion. The model is solved numerically to elucidate the effects of different diffusivity values of different layers, distribution of chemical between two adjacent layers and between material and food, mass transfer at the interface of material and food on the migration process.

  4. Modeling Electric Double-Layers Including Chemical Reaction Effects

    DEFF Research Database (Denmark)

    Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

    2014-01-01

    A physicochemical and numerical model for the transient formation of an electric double-layer between an electrolyte and a chemically-active flat surface is presented, based on a finite elements integration of the nonlinear Nernst-Planck-Poisson model including chemical reactions. The model works...

  5. Children's vulnerability to toxic chemicals: a challenge and opportunity to strengthen health and environmental policy.

    Science.gov (United States)

    Landrigan, Philip J; Goldman, Lynn R

    2011-05-01

    A key policy breakthrough occurred nearly twenty years ago with the discovery that children are far more sensitive than adults to toxic chemicals in the environment. This finding led to the recognition that chemical exposures early in life are significant and preventable causes of disease in children and adults. We review this knowledge and recommend a new policy to regulate industrial and consumer chemicals that will protect the health of children and all Americans, prevent disease, and reduce health care costs. The linchpins of a new US chemical policy will be: first, a legally mandated requirement to test the toxicity of chemicals already in commerce, prioritizing chemicals in the widest use, and incorporating new assessment technologies; second, a tiered approach to premarket evaluation of new chemicals; and third, epidemiologic monitoring and focused health studies of exposed populations.

  6. Incorporating Health Impacts from Exposure to Chemicals in Food Packaging in LCA

    OpenAIRE

    Ernstoff, Alexi; Trier, Xenia; JOLLIET Oliver; Fantke, Peter

    2014-01-01

    Life cycle assessments (LCA) on the environmental and public health impacts of food and beverage packaging materials have found some advantages to plastic over glass. Entirely missing from these evaluations are the health impacts of possible chemical, e.g. endocrine dis-ruptor, exposure through migration of chemicals from the packaging into the food product. We build a framework based on a life cycle perspective to predict which chemicals may be in a package that are not intentionally added i...

  7. Health behaviors of people with hypertension: health belief model

    Directory of Open Access Journals (Sweden)

    Ariane Alves Barros

    2014-09-01

    Full Text Available This study aimed to identify the lifestyle of hypertensive patients, focusing on their health behaviors in light of the Health Belief Model. This is a descriptive cross-sectional study with a sample of 133 patients over 18 years old, with hypertension, registered in the Clinical Management System for Hypertension and Diabetes Mellitus in Primary Care, and monitored in five health centers in Fortaleza, CE, Brazil, chosen randomly and probabilistically. Data collection happened through a structured interview that was designed based on the Health Belief Model, from March to December 2013. Participants perceived the disease’s severity and felt susceptible to develop complications from hypertension. They reported receiving treatment correctly; however, the values ​​of blood pressure, waist-hip ratio, and body mass index were high. Thus, it is necessary that health professionals implement strategies that favor hypertensive patients who are undergoing treatment to have healthy behavior.

  8. A chemical model of meteoric ablation

    Directory of Open Access Journals (Sweden)

    T. Vondrak

    2008-07-01

    Full Text Available Most of the extraterrestrial dust entering the Earth's atmosphere ablates to produce metal vapours, which have significant effects on the aeronomy of the upper mesosphere and lower thermosphere. A new Chemical Ablation Model (CAMOD is described which treats the physics and chemistry of ablation, by including the following processes: sputtering by inelastic collisions with air molecules before the meteoroid melts; evaporation of atoms and oxides from the molten particle; diffusion-controlled migration of the volatile constituents (Na and K through the molten particle; and impact ionization of the ablated fragments by hyperthermal collisions with air molecules. Evaporation is based on thermodynamic equilibrium in the molten meteoroid (treated as a melt of metal oxides, and between the particle and surrounding vapour phase. The loss rate of each element is then determined assuming Langmuir evaporation. CAMOD successfully predicts the meteor head echo appearance heights, observed from incoherent scatter radars, over a wide range of meteoroid velocities. The model also confirms that differential ablation explains common-volume lidar observations of K, Ca and Ca+ in fresh meteor trails. CAMOD is then used to calculate the injection rates into the atmosphere of a variety of elements as a function of altitude, integrated over the meteoroid mass and velocity distributions. The most abundant elements (Fe, Mg and Si have peak injection rates around 85 km, with Na and K about 8 km higher. The more refractory element Ca ablates around 82 km with a Na:Ca ratio of 4:1, which does therefore not explain the depletion of atomic Ca to Na, by more than 2 orders of magnitude, in the upper mesosphere. Diffusion of the most volatile elements (Na and K does not appear to be rate-limiting except in the fastest meteoroids. Non-thermal sputtering causes ~35% mass loss from the fastest (~60–70 km s−1 and smallest (10−17–10

  9. A chemical model of meteoric ablation

    Directory of Open Access Journals (Sweden)

    T. Vondrak

    2008-12-01

    Full Text Available Most of the extraterrestrial dust entering the Earth's atmosphere ablates to produce metal vapours, which have significant effects on the aeronomy of the upper mesosphere and lower thermosphere. A new Chemical Ablation Model (CAMOD is described which treats the physics and chemistry of ablation, by including the following processes: sputtering by inelastic collisions with air molecules before the meteoroid melts; evaporation of atoms and oxides from the molten particle; diffusion-controlled migration of the volatile constituents (Na and K through the molten particle; and impact ionization of the ablated fragments by hyperthermal collisions with air molecules. Evaporation is based on thermodynamic equilibrium in the molten meteoroid (treated as a melt of metal oxides, and between the particle and surrounding vapour phase. The loss rate of each element is then determined assuming Langmuir evaporation. CAMOD successfully predicts the meteor head echo appearance heights, observed from incoherent scatter radars, over a wide range of meteoroid velocities. The model also confirms that differential ablation explains common-volume lidar observations of K, Ca and Ca+ in fresh meteor trails. CAMOD is then used to calculate the injection rates into the atmosphere of a variety of elements as a function of altitude, integrated over the meteoroid mass and velocity distributions. The most abundant elements (Fe, Mg and Si have peak injection rates around 85 km, with Na and K about 8 km higher. The more refractory element Ca ablates around 82 km with a Na:Ca ratio of 4:1, which does therefore not explain the depletion of atomic Ca to Na, by more than 2 orders of magnitude, in the upper mesosphere. Diffusion of the most volatile elements (Na and K does not appear to be rate-limiting except in the fastest meteoroids. Non-thermal sputtering causes ~35% mass loss from the fastest (~60–70 km s−1 and smallest (10−17–10

  10. The Consumer Health Information System Adoption Model.

    Science.gov (United States)

    Monkman, Helen; Kushniruk, Andre W

    2015-01-01

    Derived from overlapping concepts in consumer health, a consumer health information system refers to any of the broad range of applications, tools, and educational resources developed to empower consumers with knowledge, techniques, and strategies, to manage their own health. As consumer health information systems become increasingly popular, it is important to explore the factors that impact their adoption and success. Accumulating evidence indicates a relationship between usability and consumers' eHealth Literacy skills and the demands consumer HISs place on their skills. Here, we present a new model called the Consumer Health Information System Adoption Model, which depicts both consumer eHealth literacy skills and system demands on eHealth literacy as moderators with the potential to affect the strength of relationship between usefulness and usability (predictors of usage) and adoption, value, and successful use (actual usage outcomes). Strategies for aligning these two moderating factors are described.

  11. Using Physiologically-Based Pharmacokinetic Models to Incorporate Chemical and Non-Chemical Stressors into Cumulative Risk Assessment: A Case Study of Pesticide Exposures

    Directory of Open Access Journals (Sweden)

    Jonathan I. Levy

    2012-05-01

    Full Text Available Cumulative risk assessment has been proposed as an approach to evaluate the health risks associated with simultaneous exposure to multiple chemical and non-chemical stressors. Physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD models can allow for the inclusion and evaluation of multiple stressors, including non-chemical stressors, but studies have not leveraged PBPK/PD models to jointly consider these disparate exposures in a cumulative risk context. In this study, we focused on exposures to organophosphate (OP pesticides for children in urban low-income environments, where these children would be simultaneously exposed to other pesticides (including pyrethroids and non-chemical stressors that may modify the effects of these exposures (including diet. We developed a methodological framework to evaluate chemical and non-chemical stressor impacts on OPs, utilizing an existing PBPK/PD model for chlorpyrifos. We evaluated population-specific stressors that would influence OP doses or acetylcholinesterase (AChE inhibition, the relevant PD outcome. We incorporated the impact of simultaneous exposure to pyrethroids and dietary factors on OP dose through the compartments of metabolism and PD outcome within the PBPK model, and simulated combinations of stressors across multiple exposure ranges and potential body weights. Our analyses demonstrated that both chemical and non-chemical stressors can influence the health implications of OP exposures, with up to 5-fold variability in AChE inhibition across combinations of stressor values for a given OP dose. We demonstrate an approach for modeling OP risks in the presence of other population-specific environmental stressors, providing insight about co-exposures and variability factors that most impact OP health risks and contribute to children’s cumulative health risk from pesticides. More generally, this framework can be used to inform cumulative risk assessment for any compound impacted by

  12. Fate modelling of chemical compounds with incomplete data sets

    DEFF Research Database (Denmark)

    Birkved, Morten; Heijungs, Reinout

    2011-01-01

    Impact assessment of chemical compounds in Life Cycle Impact Assessment (LCIA) and Environmental Risk Assessment (ERA) requires a vast amount of data on the properties of the chemical compounds being assessed. These data are used in multi-media fate and exposure models, to calculate risk levels...... in an approximate way. The idea is that not all data needed in a multi-media fate and exposure model are completely independent and equally important, but that there are physical-chemical and biological relationships between sets of chemical properties. A statistical model is constructed to underpin this assumption...

  13. Formal modeling of a system of chemical reactions under uncertainty.

    Science.gov (United States)

    Ghosh, Krishnendu; Schlipf, John

    2014-10-01

    We describe a novel formalism representing a system of chemical reactions, with imprecise rates of reactions and concentrations of chemicals, and describe a model reduction method, pruning, based on the chemical properties. We present two algorithms, midpoint approximation and interval approximation, for construction of efficient model abstractions with uncertainty in data. We evaluate computational feasibility by posing queries in computation tree logic (CTL) on a prototype of extracellular-signal-regulated kinase (ERK) pathway.

  14. Voltammetry as a Model for Teaching Chemical Instrumentation.

    Science.gov (United States)

    Gunasingham, H.; Ang, K. P.

    1985-01-01

    Voltammetry is used as a model for teaching chemical instrumentation to chemistry undergraduates at the National University of Singapore. Lists six criteria used to select a successful teaching model and shows how voltammetry satisfies each criterion. (JN)

  15. Occupational Health Impacts Due to Exposure to Organic Chemicals over an Entire Product Life Cycle.

    Science.gov (United States)

    Kijko, Gaël; Jolliet, Olivier; Margni, Manuele

    2016-12-06

    This article presents an innovative approach to include occupational exposures to organic chemicals in life cycle impact assessment (LCIA) by building on the characterization factors set out in Kijko et al. (2015) to calculate the potential impact of occupational exposure over the entire supply chain of product or service. Based on an economic input-output model and labor and economic data, the total impacts per dollar of production are provided for 430 commodity categories and range from 0.025 to 6.6 disability-adjusted life years (DALY) per million dollar of final economic demand. The approach is applied on a case study assessing human health impacts over the life cycle of a piece of office furniture. It illustrates how to combine monitoring data collected at the manufacturing facility and averaged sector specific data to model the entire supply chain. This paper makes the inclusion of occupational exposure to chemicals fully compatible with the LCA framework by including the supply chain of a given production process and will help industries focus on the leading causes of human health impacts and prevent impact shifting.

  16. Modeling Chemical Reactors I: Quiescent Reactors

    CERN Document Server

    Michoski, C E; Schmitz, P G

    2010-01-01

    We introduce a fully generalized quiescent chemical reactor system in arbitrary space $\\vdim =1,2$ or 3, with $n\\in\\mathbb{N}$ chemical constituents $\\alpha_{i}$, where the character of the numerical solution is strongly determined by the relative scaling between the local reactivity of species $\\alpha_{i}$ and the local functional diffusivity $\\mathscr{D}_{ij}(\\alpha)$ of the reaction mixture. We develop an operator time-splitting predictor multi-corrector RK--LDG scheme, and utilize $hp$-adaptivity relying only on the entropy $\\mathscr{S}_{\\mathfrak{R}}$ of the reactive system $\\mathfrak{R}$. This condition preserves these bounded nonlinear entropy functionals as a necessarily enforced stability condition on the coupled system. We apply this scheme to a number of application problems in chemical kinetics; including a difficult classical problem arising in nonequilibrium thermodynamics known as the Belousov-Zhabotinskii reaction where we utilize a concentration-dependent diffusivity tensor $\\mathscr{D}_{ij}(...

  17. The Implications of Death for Health: A Terror Management Health Model for Behavioral Health Promotion

    Science.gov (United States)

    Goldenberg, Jamie L.; Arndt, Jamie

    2008-01-01

    This article introduces a terror management health model (TMHM). The model integrates disparate health and social psychology literatures to elucidate how the conscious and nonconscious awareness of death can influence the motivational orientation that is most operative in the context of health decisions. Three formal propositions are presented.…

  18. [Evaluation model for municipal health planning management].

    Science.gov (United States)

    Berretta, Isabel Quint; Lacerda, Josimari Telino de; Calvo, Maria Cristina Marino

    2011-11-01

    This article presents an evaluation model for municipal health planning management. The basis was a methodological study using the health planning theoretical framework to construct the evaluation matrix, in addition to an understanding of the organization and functioning designed by the Planning System of the Unified National Health System (PlanejaSUS) and definition of responsibilities for the municipal level under the Health Management Pact. The indicators and measures were validated using the consensus technique with specialists in planning and evaluation. The applicability was tested in 271 municipalities (counties) in the State of Santa Catarina, Brazil, based on population size. The proposed model features two evaluative dimensions which reflect the municipal health administrator's commitment to planning: the guarantee of resources and the internal and external relations needed for developing the activities. The data were analyzed using indicators, sub-dimensions, and dimensions. The study concludes that the model is feasible and appropriate for evaluating municipal performance in health planning management.

  19. Modelling Human Exposure to Chemicals in Food

    NARCIS (Netherlands)

    Slob W

    1993-01-01

    Exposure to foodborne chemicals is often estimated using the average consumption pattern in the human population. To protect the human population instead of the average individual, however, interindividual variability in consumption behaviour must be taken into account. This report shows how food

  20. Occupational safety and health guidelines for chemical hazards. Supplement IV-OHG

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    This document is the fourth in a seris of supplements to the 1981 Publication NIOSH/OSHA Occupational Health Guidelines for Chemical Hazards. The 62 guidelines presented here in the fourth supplement include 11 revisions of previously issued guidelines and 51 new guidelines. The 62 occupational safety and health guidelines presented here are being published to disseminate technical information about chemical hazards to workers, employers, and occupational safety and health professionals. Each guideline includes (1) data on the chemical name and synonyms, cemnical and physical properties, exposure limits, and signs and symptoms of exposure, personal protective equipment, and control procedures.

  1. Environmental and health hazard ranking and assessment of plastic polymers based on chemical composition

    Energy Technology Data Exchange (ETDEWEB)

    Lithner, Delilah, E-mail: delilah.lithner@gmail.com; Larsson, Ake; Dave, Goeran

    2011-08-15

    Plastics constitute a large material group with a global annual production that has doubled in 15 years (245 million tonnes in 2008). Plastics are present everywhere in society and the environment, especially the marine environment, where large amounts of plastic waste accumulate. The knowledge of human and environmental hazards and risks from chemicals associated with the diversity of plastic products is very limited. Most chemicals used for producing plastic polymers are derived from non-renewable crude oil, and several are hazardous. These may be released during the production, use and disposal of the plastic product. In this study the environmental and health hazards of chemicals used in 55 thermoplastic and thermosetting polymers were identified and compiled. A hazard ranking model was developed for the hazard classes and categories in the EU classification and labelling (CLP) regulation which is based on the UN Globally Harmonized System. The polymers were ranked based on monomer hazard classifications, and initial assessments were made. The polymers that ranked as most hazardous are made of monomers classified as mutagenic and/or carcinogenic (category 1A or 1B). These belong to the polymer families of polyurethanes, polyacrylonitriles, polyvinyl chloride, epoxy resins, and styrenic copolymers. All have a large global annual production (1-37 million tonnes). A considerable number of polymers (31 out of 55) are made of monomers that belong to the two worst of the ranking model's five hazard levels, i.e. levels IV-V. The polymers that are made of level IV monomers and have a large global annual production (1-5 million tonnes) are phenol formaldehyde resins, unsaturated polyesters, polycarbonate, polymethyl methacrylate, and urea-formaldehyde resins. This study has identified hazardous substances used in polymer production for which the risks should be evaluated for decisions on the need for risk reduction measures, substitution, or even phase out

  2. Hierarchical dose-response modeling for high-throughput toxicity screening of environmental chemicals.

    Science.gov (United States)

    Wilson, Ander; Reif, David M; Reich, Brian J

    2014-03-01

    High-throughput screening (HTS) of environmental chemicals is used to identify chemicals with high potential for adverse human health and environmental effects from among the thousands of untested chemicals. Predicting physiologically relevant activity with HTS data requires estimating the response of a large number of chemicals across a battery of screening assays based on sparse dose-response data for each chemical-assay combination. Many standard dose-response methods are inadequate because they treat each curve separately and under-perform when there are as few as 6-10 observations per curve. We propose a semiparametric Bayesian model that borrows strength across chemicals and assays. Our method directly parametrizes the efficacy and potency of the chemicals as well as the probability of response. We use the ToxCast data from the U.S. Environmental Protection Agency (EPA) as motivation. We demonstrate that our hierarchical method provides more accurate estimates of the probability of response, efficacy, and potency than separate curve estimation in a simulation study. We use our semiparametric method to compare the efficacy of chemicals in the ToxCast data to well-characterized reference chemicals on estrogen receptor α (ERα) and peroxisome proliferator-activated receptor γ (PPARγ) assays, then estimate the probability that other chemicals are active at lower concentrations than the reference chemicals.

  3. Global Health Innovation Technology Models

    Directory of Open Access Journals (Sweden)

    Kimberly Harding

    2016-04-01

    Full Text Available Chronic technology and business process disparities between High Income, Low Middle Income and Low Income (HIC, LMIC, LIC research collaborators directly prevent the growth of sustainable Global Health innova‐ tion for infectious and rare diseases. There is a need for an Open Source-Open Science Architecture Framework to bridge this divide. We are proposing such a framework for consideration by the Global Health community, by utiliz‐ ing a hybrid approach of integrating agnostic Open Source technology and healthcare interoperability standards and Total Quality Management principles. We will validate this architecture framework through our programme called Project Orchid. Project Orchid is a conceptual Clinical Intelligence Exchange and Virtual Innovation platform utilizing this approach to support clinical innovation efforts for multi-national collaboration that can be locally sustainable for LIC and LMIC research cohorts. The goal is to enable LIC and LMIC research organizations to acceler‐ ate their clinical trial process maturity in the field of drug discovery, population health innovation initiatives and public domain knowledge networks. When sponsored, this concept will be tested by 12 confirmed clinical research and public health organizations in six countries. The potential impact of this platform is reduced drug discovery and public health innovation lag time and improved clinical trial interventions, due to reliable clinical intelligence and bio-surveillance across all phases of the clinical innovation process.

  4. Studies of Trace Gas Chemical Cycles Using Observations, Inverse Methods and Global Chemical Transport Models

    Science.gov (United States)

    Prinn, Ronald G.

    2001-01-01

    For interpreting observational data, and in particular for use in inverse methods, accurate and realistic chemical transport models are essential. Toward this end we have, in recent years, helped develop and utilize a number of three-dimensional models including the Model for Atmospheric Transport and Chemistry (MATCH).

  5. Endocrine-disrupting chemicals and public health protection

    DEFF Research Database (Denmark)

    Zoeller, R Thomas; Brown, T R; Doan, L L

    2012-01-01

    exposures to have potent and irreversible effects. Finally, with regard to the current program designed to detect putative EDC, namely, the Endocrine Disruptor Screening Program, we offer recommendations for strengthening this program through the incorporation of basic endocrine principles to promote......An endocrine-disrupting chemical (EDC) is an exogenous chemical, or mixture of chemicals, that can interfere with any aspect of hormone action. The potential for deleterious effects of EDC must be considered relative to the regulation of hormone synthesis, secretion, and actions and the variability...... in regulation of these events across the life cycle. The developmental age at which EDC exposures occur is a critical consideration in understanding their effects. Because endocrine systems exhibit tissue-, cell-, and receptor-specific actions during the life cycle, EDC can produce complex, mosaic effects...

  6. New trajectory-driven aerosol and chemical process model Chemical and Aerosol Lagrangian Model (CALM

    Directory of Open Access Journals (Sweden)

    P. Tunved

    2010-11-01

    Full Text Available A new Chemical and Aerosol Lagrangian Model (CALM has been developed and tested. The model incorporates all central aerosol dynamical processes, from nucleation, condensation, coagulation and deposition to cloud formation and in-cloud processing. The model is tested and evaluated against observations performed at the SMEAR II station located at Hyytiälä (61° 51' N, 24° 17' E over a time period of two years, 2000–2001. The model shows good agreement with measurements throughout most of the year, but fails in reproducing the aerosol properties during the winter season, resulting in poor agreement between model and measurements especially during December–January. Nevertheless, through the rest of the year both trends and magnitude of modal concentrations show good agreement with observation, as do the monthly average size distribution properties. The model is also shown to capture individual nucleation events to a certain degree. This indicates that nucleation largely is controlled by the availability of nucleating material (as prescribed by the [H2SO4], availability of condensing material (in this model 15% of primary reactions of monoterpenes (MT are assumed to produce low volatile species and the properties of the size distribution (more specifically, the condensation sink. This is further demonstrated by the fact that the model captures the annual trend in nuclei mode concentration. The model is also used, alongside sensitivity tests, to examine which processes dominate the aerosol size distribution physical properties. It is shown, in agreement with previous studies, that nucleation governs the number concentration during transport from clean areas. It is also shown that primary number emissions almost exclusively govern the CN concentration when air from Central Europe is advected north over Scandinavia. We also show that biogenic emissions have a large influence on the amount of potential CCN observed

  7. 75 FR 52355 - Draft National Conversation on Public Health and Chemical Exposures Work Group Reports...

    Science.gov (United States)

    2010-08-25

    ... Prevention Draft National Conversation on Public Health and Chemical Exposures Work Group Reports... exposures. This notice announces the availability of draft National Conversation work group reports for... National Conversation Leadership Council and facilitating the work group process. DATES: Draft work...

  8. Chemically induced intestinal damage models in zebrafish larvae.

    Science.gov (United States)

    Oehlers, Stefan H; Flores, Maria Vega; Hall, Christopher J; Okuda, Kazuhide S; Sison, John Oliver; Crosier, Kathryn E; Crosier, Philip S

    2013-06-01

    Several intestinal damage models have been developed using zebrafish, with the aim of recapitulating aspects of human inflammatory bowel disease (IBD). These experimentally induced inflammation models have utilized immersion exposure to an array of colitogenic agents (including live bacteria, bacterial products, and chemicals) to induce varying severity of inflammation. This technical report describes methods used to generate two chemically induced intestinal damage models using either dextran sodium sulfate (DSS) or trinitrobenzene sulfonic acid (TNBS). Methods to monitor intestinal damage and inflammatory processes, and chemical-genetic methods to manipulate the host response to injury are also described.

  9. Upper Secondary Teachers' Knowledge for Teaching Chemical Bonding Models

    Science.gov (United States)

    Bergqvist, Anna; Drechsler, Michal; Chang Rundgren, Shu-Nu

    2016-01-01

    Researchers have shown a growing interest in science teachers' professional knowledge in recent decades. The article focuses on how chemistry teachers impart chemical bonding, one of the most important topics covered in upper secondary school chemistry courses. Chemical bonding is primarily taught using models, which are key for understanding…

  10. THEORETICAL CHEMICAL ENGINEERING - Modeling and Simulation by Christo Boyadjiev

    Directory of Open Access Journals (Sweden)

    Simeon Oka

    2010-01-01

    Full Text Available Book Title: THEORETICAL CHEMICAL ENGINEERING - Modeling and Simulation Author(s: Christo Boyadjiev Institute of Chemical Engineering, Bulgarian Academy of Science, Sofia Publisher: Springer, 2010 ISBN: 978-3-642-10777-1 Review by: Prof. Simeon Oka, Ph. D., Scientific advisor - retired

  11. Reevaluation of 1999 Health-Based Environmental Screening Levels (HBESLs) for Chemical Warfare Agents

    Energy Technology Data Exchange (ETDEWEB)

    Watson, Annetta Paule [ORNL; Dolislager, Fredrick G [ORNL

    2007-05-01

    This report evaluates whether new information and updated scientific models require that changes be made to previously published health-based environmental soil screening levels (HBESLs) and associated environmental fate/breakdown information for chemical warfare agents (USACHPPM 1999). Specifically, the present evaluation describes and compares changes that have been made since 1999 to U.S. Environmental Protection Agency (EPA) risk assessment models, EPA exposure assumptions, as well as to specific chemical warfare agent parameters (e.g., toxicity values). Comparison was made between screening value estimates recalculated with current assumptions and earlier health-based environmental screening levels presented in 1999. The chemical warfare agents evaluated include the G-series and VX nerve agents and the vesicants sulfur mustard (agent HD) and Lewisite (agent L). In addition, key degradation products of these agents were also evaluated. Study findings indicate that the combined effect of updates and/or changes to EPA risk models, EPA default exposure parameters, and certain chemical warfare agent toxicity criteria does not result in significant alteration to the USACHPPM (1999) health-based environmental screening level estimates for the G-series and VX nerve agents or the vesicant agents HD and L. Given that EPA's final position on separate Tier 1 screening levels for indoor and outdoor worker screening assessments has not yet been released as of May 2007, the study authors find that the 1999 screening level estimates (see Table ES.1) are still appropriate and protective for screening residential as well as nonresidential sites. As such, risk management decisions made on the basis of USACHPPM (1999) recommendations do not require reconsideration. While the 1999 HBESL values are appropriate for continued use as general screening criteria, the updated '2007' estimates (presented below) that follow the new EPA protocols currently under development

  12. Psychosocial environment: a health promotion model.

    Science.gov (United States)

    Kar, S B

    1983-01-01

    This article presents a multidimensional model of psychosocial determinants of health behavior for health promotion research and policy analysis. Frequently, health promotion focuses almost exclusively on intrapsychic determinants and on individual level behavior. Based upon Field Theory and attitude theories, this proposed model holds that in populations with comparable sociodemographic and biological status (exogenous variables) a health behavior is a function of direct and interaction effects of five key intrapsychic and external variables. These are: behavioral intentions, social support, accessibility of means for action, personal autonomy, and action situation. Empirical tests with cross-cultural studies in Venezuela, Kenya, and the Philippines provide substantial support for the model. The findings suggest that while health promotion strategies should deal with intrapsychic determinants of behavior, key extrapsychic factors (such as social support, quality and accessibility of health care measures, and situational factors) all have direct and independent effects on health behavior as well. Health promotion research and interventions which aim exclusively at intrapsychic determinants would thus have rather limited overall value. The article discusses key research and policy implications of the model presented.

  13. Psychoneuroimmunology and health psychology: an integrative model.

    Science.gov (United States)

    Lutgendorf, Susan K; Costanzo, Erin S

    2003-08-01

    The biopsychosocial model describes interactions between psychosocial and biological factors in the etiology and progression of disease. How an individual interprets and responds to the environment determines responses to stress, influences health behaviors, contributes to the neuroendocrine and immune response, and may ultimately affect health outcomes. Health psychology interventions are designed to modulate the stress response and improve health behaviors by teaching individuals more adaptive methods of interpreting life challenges and more effective coping responses. These interactions are discussed in the context of aging.

  14. Comparison of Family Clinic Community Health Service Model with State-owned Community Health Service Model

    Institute of Scientific and Technical Information of China (English)

    万方荣; 卢祖洵; 张金隆

    2002-01-01

    Summary: Based on a survey of community health service organization in several cities, communi-ty health service model based on the family clinic was compared with state-owned communityhealth service model, and status quo, advantages and problems of family community health serviceorganization were analyzed. Furthermore, policies for the management of community health ser-vice organization based on the family clinic were put forward.

  15. Potts Flux Tube Model at Nonzero Chemical Potential

    CERN Document Server

    Condella, J; Condella, Jac; Tar, Carleton De

    2000-01-01

    We model the deconfinement phase transition in quantum chromodynamics at nonzero baryon number density and large quark mass by extending the flux tube model (three-state, three-dimensional Potts model) to nonzero chemical potential. In a direct numerical simulation we confirm mean-field-theory predictions that the deconfinement transition does not occur in a baryon-rich environment.

  16. NONLINEAR MODEL PREDICTIVE CONTROL OF CHEMICAL PROCESSES

    Directory of Open Access Journals (Sweden)

    R. G. SILVA

    1999-03-01

    Full Text Available A new algorithm for model predictive control is presented. The algorithm utilizes a simultaneous solution and optimization strategy to solve the model's differential equations. The equations are discretized by equidistant collocation, and along with the algebraic model equations are included as constraints in a nonlinear programming (NLP problem. This algorithm is compared with the algorithm that uses orthogonal collocation on finite elements. The equidistant collocation algorithm results in simpler equations, providing a decrease in computation time for the control moves. Simulation results are presented and show a satisfactory performance of this algorithm.

  17. The need for better public health decisions on chemicals released into our environment.

    Science.gov (United States)

    Woodruff, Tracey J; Burke, Thomas A; Zeise, Lauren

    2011-05-01

    Protecting the health of the public-particularly the most vulnerable groups, such as children-requires rethinking current approaches to reducing environmental risks. We review the evolving understanding of the relationship between exposure to chemicals in the environment and disease, as well as the current state of managing those chemicals. We present recommendations to improve current approaches, including changing the burden of proof so that chemicals are not presumed safe in the absence of scientific data. We also propose modernizing approaches to assessing health risks.

  18. Soil ecosystem health and services – Evaluation of ecological indicators susceptible to chemical stressors

    NARCIS (Netherlands)

    Thomsen, M.; Faber, J.H.; Sorensen, P.B.

    2012-01-01

    The paper presents a methodological framework for quantifying soil ecosystem health with special focus on chemical stressors and ecological integrity as determinant for biological productivity of soil ecosystems. Ecological risk assessment is needed to facilitate the assessment of soil health and th

  19. Center for Integrated Nanotechnologies (CINT) Chemical Release Modeling Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Stirrup, Timothy Scott [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-12-20

    This evaluation documents the methodology and results of chemical release modeling for operations at Building 518, Center for Integrated Nanotechnologies (CINT) Core Facility. This evaluation is intended to supplement an update to the CINT [Standalone] Hazards Analysis (SHA). This evaluation also updates the original [Design] Hazards Analysis (DHA) completed in 2003 during the design and construction of the facility; since the original DHA, additional toxic materials have been evaluated and modeled to confirm the continued low hazard classification of the CINT facility and operations. This evaluation addresses the potential catastrophic release of the current inventory of toxic chemicals at Building 518 based on a standard query in the Chemical Information System (CIS).

  20. Towards consensus in chemical characterization modeling for LCA:

    DEFF Research Database (Denmark)

    Rosenbaum, Ralf; Hauschild, Michael Zwicky; Bachmann, Till;

    2006-01-01

    A comprehensive LCIA characterization model comparison is being undertaken in the UNEP/SETAC Life Cycle Initiative, focusing on toxicity impacts and directly involving the developers of all models included. The main objective is to identify where differences come from, what indispensable model...... components are and if there can be a consensus model built from them, leading towards recommended practice in chemical characterization for LCIA. The models were selected in an open process inviting all models identified to be capable of characterizing a chemical in terms of environmental fate, human...... exposure, human toxicity and ecotoxicity. The invitation was accepted by the developers of CalTOX, IMPACT 2002, USES-LCA, EDIP, WATSON, and EcoSense. A consistent chemical test set comprising 66 organic (generic, amphiphilic and dissociating) and inorganic (metals, salts) compounds was selected...

  1. Chemical Kinetic Models for HCCI and Diesel Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Pitz, W J; Westbrook, C K; Mehl, M; Sarathy, S M

    2010-11-15

    Predictive engine simulation models are needed to make rapid progress towards DOE's goals of increasing combustion engine efficiency and reducing pollutant emissions. These engine simulation models require chemical kinetic submodels to allow the prediction of the effect of fuel composition on engine performance and emissions. Chemical kinetic models for conventional and next-generation transportation fuels need to be developed so that engine simulation tools can predict fuel effects. The objectives are to: (1) Develop detailed chemical kinetic models for fuel components used in surrogate fuels for diesel and HCCI engines; (2) Develop surrogate fuel models to represent real fuels and model low temperature combustion strategies in HCCI and diesel engines that lead to low emissions and high efficiency; and (3) Characterize the role of fuel composition on low temperature combustion modes of advanced combustion engines.

  2. Thermodynamically consistent model calibration in chemical kinetics

    Directory of Open Access Journals (Sweden)

    Goutsias John

    2011-05-01

    Full Text Available Abstract Background The dynamics of biochemical reaction systems are constrained by the fundamental laws of thermodynamics, which impose well-defined relationships among the reaction rate constants characterizing these systems. Constructing biochemical reaction systems from experimental observations often leads to parameter values that do not satisfy the necessary thermodynamic constraints. This can result in models that are not physically realizable and may lead to inaccurate, or even erroneous, descriptions of cellular function. Results We introduce a thermodynamically consistent model calibration (TCMC method that can be effectively used to provide thermodynamically feasible values for the parameters of an open biochemical reaction system. The proposed method formulates the model calibration problem as a constrained optimization problem that takes thermodynamic constraints (and, if desired, additional non-thermodynamic constraints into account. By calculating thermodynamically feasible values for the kinetic parameters of a well-known model of the EGF/ERK signaling cascade, we demonstrate the qualitative and quantitative significance of imposing thermodynamic constraints on these parameters and the effectiveness of our method for accomplishing this important task. MATLAB software, using the Systems Biology Toolbox 2.1, can be accessed from http://www.cis.jhu.edu/~goutsias/CSS lab/software.html. An SBML file containing the thermodynamically feasible EGF/ERK signaling cascade model can be found in the BioModels database. Conclusions TCMC is a simple and flexible method for obtaining physically plausible values for the kinetic parameters of open biochemical reaction systems. It can be effectively used to recalculate a thermodynamically consistent set of parameter values for existing thermodynamically infeasible biochemical reaction models of cellular function as well as to estimate thermodynamically feasible values for the parameters of new

  3. Incorporating Health Impacts from Exposure to Chemicals in Food Packaging in LCA

    DEFF Research Database (Denmark)

    Ernstoff, Alexi; Trier, Xenia; Jolliet, Oliver

    2014-01-01

    Life cycle assessments (LCA) on the environmental and public health impacts of food and beverage packaging materials have found some advantages to plastic over glass. Entirely missing from these evaluations are the health impacts of possible chemical, e.g. endocrine dis-ruptor, exposure through...... within the CPCAT database related to food-contact materials; out of these 107 are potential endocrine disruptors according to the TEDX list of endocrine disruptors. We also build a framework in an effort to begin harmonizing LCA to include health impacts of chemical exposure related to food packaging...

  4. In silico screening of estrogen-like chemicals based on different nonlinear classification models.

    Science.gov (United States)

    Liu, Huanxiang; Papa, Ester; Walker, John D; Gramatica, Paola

    2007-07-01

    Increasing concern is being shown by the scientific community, government regulators, and the public about endocrine-disrupting chemicals that are adversely affecting human and wildlife health through a variety of mechanisms. There is a great need for an effective means of rapidly assessing endocrine-disrupting activity, especially estrogen-simulating activity, because of the large number of such chemicals in the environment. In this study, quantitative structure activity relationship (QSAR) models were developed to quickly and effectively identify possible estrogen-like chemicals based on 232 structurally-diverse chemicals (training set) by using several nonlinear classification methodologies (least-square support vector machine (LS-SVM), counter-propagation artificial neural network (CP-ANN), and k nearest neighbour (kNN)) based on molecular structural descriptors. The models were externally validated by 87 chemicals (prediction set) not included in the training set. All three methods can give satisfactory prediction results both for training and prediction sets, and the most accurate model was obtained by the LS-SVM approach through the comparison of performance. In addition, our model was also applied to about 58,000 discrete organic chemicals; about 76% were predicted not to bind to Estrogen Receptor. The obtained results indicate that the proposed QSAR models are robust, widely applicable and could provide a feasible and practical tool for the rapid screening of potential estrogens.

  5. Grape Seed Oil Compounds: Biological and Chemical Actions for Health

    Science.gov (United States)

    Garavaglia, Juliano; Markoski, Melissa M.; Oliveira, Aline; Marcadenti, Aline

    2016-01-01

    Grape seed oil is rich in phenolic compounds, fatty acids, and vitamins, with economic importance to pharmaceutical, cosmetic, and food industry. Its use as an edible oil has also been suggested, especially due to its pleasant sensory characteristics. Grape seed oil has beneficial properties for health that are mainly detected by in vitro studies, such as anti-inflammatory, cardioprotective, antimicrobial, and anticancer properties, and may interact with cellular and molecular pathways. These effects have been related to grape seed oil constituents, mainly tocopherol, linolenic acid, resveratrol, quercetin, procyanidins, carotenoids, and phytosterols. The aim of this article was to briefly review the composition and nutritional aspects of grape seed oil, the interactions of its compounds with molecular and cellular pathways, and its possible beneficial effects on health. PMID:27559299

  6. Engineered Barrier System: Physical and Chemical Environment Model

    Energy Technology Data Exchange (ETDEWEB)

    D. M. Jolley; R. Jarek; P. Mariner

    2004-02-09

    The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports.

  7. Walnuts (Juglans regia) Chemical Composition and Research in Human Health.

    Science.gov (United States)

    Hayes, David; Angove, Michael J; Tucci, Joe; Dennis, Christina

    2016-06-10

    Walnuts are among the most widely consumed commercially grown tree nuts in the world. Many health benefits have been claimed for the consumption of these, including reduced risk of cardiovascular disease, coronary heart disease, type II diabetes treatment, and prevention and treatment of certain cancers, and the lessening of symptoms attributed to age-related and other neurological disorders. The health-promoting benefits of walnut consumption are ascribed to its fatty acid profile, which is rich in polyunsaturated fatty acids with a particularly high ω3:ω6 ratio-the highest among all the tree nuts. The content of polyphenols and other phytochemicals in walnuts, with their claimed cytotoxic properties, also make them an attractive candidate for research for the prevention of free radical-induced nucleic acid damage. Research of walnut consumption in humans and animals employing a range of data sets and statistical methods suggest that walnuts may be considered a safe potential nutraceutical or possibly pharmaceutical substance. Nevertheless, few reviews of scientific research on the proposed benefits of these nuts exist, in spite of the numerous claims attributed to them in the lay media. This brief review article attempts to disseminate much of the information surrounding walnut consumption, and human health benefits, to other scientists and the interested general reader.

  8. Implementation and evaluation of an array of chemical solvers in a global chemical transport model

    Directory of Open Access Journals (Sweden)

    M. Lee

    2009-03-01

    Full Text Available This paper discusses the implementation and performance of an array of gas-phase chemistry solvers for the state-of-the-science GEOS-Chem global chemical transport model. The implementation is based on the Kinetic PreProcessor (KPP. Two perl parsers automatically generate the needed interfaces between GEOS-Chem and KPP, and allow access to the chemical simulation code without any additional programming effort. This work illustrates the potential of KPP to positively impact global chemical transport modeling by providing additional functionality as follows. (1 The user can select a highly efficient numerical integration method from an array of solvers available in the KPP library. (2 KPP offers extreme flexibility for studies that involve changing the chemical mechanism (e.g., a set of additional reactions is automatically translated into efficient code and incorporated into a modified global model. (3 This work provides immediate access to tangent linear, continuous adjoint, and discrete adjoint chemical models, with applications to sensitivity analysis and data assimilation.

  9. Environmental and health hazard ranking and assessment of plastic polymers based on chemical composition.

    Science.gov (United States)

    Lithner, Delilah; Larsson, Ake; Dave, Göran

    2011-08-15

    Plastics constitute a large material group with a global annual production that has doubled in 15 years (245 million tonnes in 2008). Plastics are present everywhere in society and the environment, especially the marine environment, where large amounts of plastic waste accumulate. The knowledge of human and environmental hazards and risks from chemicals associated with the diversity of plastic products is very limited. Most chemicals used for producing plastic polymers are derived from non-renewable crude oil, and several are hazardous. These may be released during the production, use and disposal of the plastic product. In this study the environmental and health hazards of chemicals used in 55 thermoplastic and thermosetting polymers were identified and compiled. A hazard ranking model was developed for the hazard classes and categories in the EU classification and labelling (CLP) regulation which is based on the UN Globally Harmonized System. The polymers were ranked based on monomer hazard classifications, and initial assessments were made. The polymers that ranked as most hazardous are made of monomers classified as mutagenic and/or carcinogenic (category 1A or 1B). These belong to the polymer families of polyurethanes, polyacrylonitriles, polyvinyl chloride, epoxy resins, and styrenic copolymers. All have a large global annual production (1-37 million tonnes). A considerable number of polymers (31 out of 55) are made of monomers that belong to the two worst of the ranking model's five hazard levels, i.e. levels IV-V. The polymers that are made of level IV monomers and have a large global annual production (1-5 million tonnes) are phenol formaldehyde resins, unsaturated polyesters, polycarbonate, polymethyl methacrylate, and urea-formaldehyde resins. This study has identified hazardous substances used in polymer production for which the risks should be evaluated for decisions on the need for risk reduction measures, substitution, or even phase out.

  10. Conceptual model of communications in public health

    Directory of Open Access Journals (Sweden)

    Марія Андріївна Знаменська

    2015-07-01

    Full Text Available Actuality. The role of communications in effective reform of public health in the country is discovered in scientific literature last time. But there are no works that fully present the system of communications in public health; this fact defined actuality of the given research.Methods. The next scientific methods are used in this work: structural and logical analysis, conceptual modeling. The systematic approach became a base of research. Results. There was elaborated conceptual model of the system of communications in public health its node idea is a consistent solution of the priority problem of supply the population of the country in whole and the separate task groups of communicative impact with complex objective information in the system of public health. At constructing of the model there were separated the next groups of problems: structural construction of the system of communication; supply of the system with resources; methods and means of communication; monitoring and assessment of efficiency of communication.Conclusions. The use of this model allows at optimal costs to eliminate the organizational and administrative defects and increase an awareness of the people in organization of public health, in maintenance and improvement of personal health

  11. Extension of association models to complex chemicals

    DEFF Research Database (Denmark)

    Avlund, Ane Søgaard

    Summary of “Extension of association models to complex chemicals”. Ph.D. thesis by Ane Søgaard Avlund The subject of this thesis is application of SAFT type equations of state (EoS). Accurate and predictive thermodynamic models are important in many industries including the petroleum industry....... The SAFT EoS was developed 20 years ago, and a large number of papers on the subject has been published since, but many issues still remain unsolved. These issues are both theoretical and practical. The SAFT theory does not account for intramolecular association, it can only treat flexible chains, and does...... not account for steric self-hindrance for tree-like structures. An important practical problem is how to obtain optimal and consistent parameters. Moreover, multifunctional associating molecules represent a special challenge. In this work two equations of state using the SAFT theory for association are used...

  12. Monks' Health: Holistic Health Care Model by Community Participation

    Directory of Open Access Journals (Sweden)

    Decha Buates

    2010-01-01

    Full Text Available Problem statement: Monks’ health tended to be a continuous increased problem. They were groups who had limitations to access health services due to their monastic disciplines and their most importance for Buddhist institution. Without urgent solution, their normal way of life would have been affected. Approach: This research aimed to study current conditions and to develop monks’ holistic health care models by community participation in central region of Thailand. The study was a qualitative research conducted in 9 temples; 3 temples in urban area, 3 in semi-urban area and 3 in rural area. Samples were 224 persons; consisted of monks, public health officers from Department of Religious Affairs, local administrative organizations and people; selected by purposive sampling method. Observation form, survey form, interview form, focus group discussion and workshop were used as research tools while data was analyzed by descriptive research. Results: The result founded that in former time culture of monks’ health care was leaned on community, social, culture and tradition. People spoke in style of central Thai language and were in agricultural sector as well as had their belief in merit, sin and elder respect. Relation in communities was in form of generosity and living as similar as relatives. When some monk got sick, they would visit, take care and give foods and medicines. Most of medicines were household remedy and Thai herbal medicine that bought from drug stores in local market or grocery stores in village and monks were sent to hospital in case of severe illness. Temple was a part of community, so they had close relation. Nowadays people increasingly worked in manufactories that caused conflicts and alienations among them. Monks leaned on local markets for receiving foods offering and most of foods were cooked from flour, sugar, coconut milk and fat. These caused three-fourth of monks having chronic disease as diabetes

  13. Bayesian molecular design with a chemical language model.

    Science.gov (United States)

    Ikebata, Hisaki; Hongo, Kenta; Isomura, Tetsu; Maezono, Ryo; Yoshida, Ryo

    2017-03-09

    The aim of computational molecular design is the identification of promising hypothetical molecules with a predefined set of desired properties. We address the issue of accelerating the material discovery with state-of-the-art machine learning techniques. The method involves two different types of prediction; the forward and backward predictions. The objective of the forward prediction is to create a set of machine learning models on various properties of a given molecule. Inverting the trained forward models through Bayes' law, we derive a posterior distribution for the backward prediction, which is conditioned by a desired property requirement. Exploring high-probability regions of the posterior with a sequential Monte Carlo technique, molecules that exhibit the desired properties can computationally be created. One major difficulty in the computational creation of molecules is the exclusion of the occurrence of chemically unfavorable structures. To circumvent this issue, we derive a chemical language model that acquires commonly occurring patterns of chemical fragments through natural language processing of ASCII strings of existing compounds, which follow the SMILES chemical language notation. In the backward prediction, the trained language model is used to refine chemical strings such that the properties of the resulting structures fall within the desired property region while chemically unfavorable structures are successfully removed. The present method is demonstrated through the design of small organic molecules with the property requirements on HOMO-LUMO gap and internal energy. The R package iqspr is available at the CRAN repository.

  14. Visual Basic and Excel in Chemical Modeling

    Science.gov (United States)

    Kaess, Michael; Easter, Jesse; Cohn, Kim

    1998-05-01

    A series of modules were prepared to model some topics in molecular mechanics and computational chemistry. In order to make modules that would be useful in personal, academic or professional situations and to make them easy to use on both IBM and Macintosh compatible computers as well as require little or no computational, advanced mathematical or programming skills we settled on Microsoft Excel as the program of choice. The release of Excel 5.0 incorporates Visual Basic. This allows the use of custom commands, menus, dialog boxes, buttons and custom on-line help.

  15. A Coupled Chemical and Mass Transport Model for Concrete Durability

    DEFF Research Database (Denmark)

    Jensen, Mads Mønster; Johannesson, Björn; Geiker, Mette Rica

    2012-01-01

    curves which is established from a set of mathematical criteria. The chemical degradation is modelled with the geochemical code iphreeqc, which provides a general tool for evaluating different paste compositions. The governing system of equations is solved by the finite element method with a Newton......-Raphson iteration scheme arising from the non-linearity. The overall model is a transient problem, solved using a single parameter formulation. The sorption hysteresis and chemical equilibrium is included as source or sink terms. The advantages with this formulation is that each node in the discrete system has......In this paper a general continuum theory is used to evaluate the service life of cement based materials, in terms of mass transport processes and chemical degradation of the solid matrix. The model established is a reactive mass transport model, based on an extended version of the Poisson...

  16. Two-Compartment Pharmacokinetic Models for Chemical Engineers

    Science.gov (United States)

    Kanneganti, Kumud; Simon, Laurent

    2011-01-01

    The transport of potassium permanganate between two continuous-stirred vessels was investigated to help chemical and biomedical engineering students understand two-compartment pharmacokinetic models. Concepts of modeling, mass balance, parameter estimation and Laplace transform were applied to the two-unit process. A good agreement was achieved…

  17. Identification of Chemical Reactor Plant’s Mathematical Model

    Directory of Open Access Journals (Sweden)

    Pyakillya Boris

    2015-01-01

    Full Text Available This work presents a solution of the identification problem of chemical reactor plant’s mathematical model. The main goal is to obtain a mathematical description of a chemical reactor plant from experimental data, which based on plant’s time response measurements. This data consists sequence of measurements for water jacket temperature and information about control input signal, which is used to govern plant’s behavior.

  18. Hydrogeochemical modeling of groundwater chemical environmental evolution in Hebei Plain

    Institute of Scientific and Technical Information of China (English)

    郭永海; 沈照理; 钟佐燊

    1997-01-01

    Using the hydrogeochemical modeling method, the groundwater chemical environmental problems of the Hebei Plain which involve increasing of hardness and total dissolved solids in piedmont area and mixing of saline water with fresh water in middle-eastern area are studied. The water-rock interactions and mass transfer along a ground-water flow path and in mixing processes are calculated. Thus the evolution mechanisms of the groundwater chemical environment are brought to light.

  19. Application of Detailed Chemical Kinetics to Combustion Instability Modeling

    Science.gov (United States)

    2016-01-04

    under two different conditions corresponding to marginally stable and unstable operation in order to evaluate the performance of the chemical kinetics...instability is a complex interaction between acoustics and the heat release due to combustion.In rocket engines, which are acoustically compact, there is...and amplitudes remains a challenge. The present article is an attempt towards addressing such discrepancies by enhancing the chemical kinetics model

  20. Implications of global climate change for the assessment and management of human health risks of chemicals in the natural environment.

    Science.gov (United States)

    Balbus, John M; Boxall, Alistair B A; Fenske, Richard A; McKone, Thomas E; Zeise, Lauren

    2013-01-01

    Global climate change (GCC) is likely to alter the degree of human exposure to pollutants and the response of human populations to these exposures, meaning that risks of pollutants could change in the future. The present study, therefore, explores how GCC might affect the different steps in the pathway from a chemical source in the environment through to impacts on human health and evaluates the implications for existing risk-assessment and management practices. In certain parts of the world, GCC is predicted to increase the level of exposure of many environmental pollutants due to direct and indirect effects on the use patterns and transport and fate of chemicals. Changes in human behavior will also affect how humans come into contact with contaminated air, water, and food. Dietary changes, psychosocial stress, and coexposure to stressors such as high temperatures are likely to increase the vulnerability of humans to chemicals. These changes are likely to have significant implications for current practices for chemical assessment. Assumptions used in current exposure-assessment models may no longer apply, and existing monitoring methods may not be robust enough to detect adverse episodic changes in exposures. Organizations responsible for the assessment and management of health risks of chemicals therefore need to be more proactive and consider the implications of GCC for their procedures and processes.

  1. Sensitivity of chemical tracers to meteorological parameters in the MOZART-3 chemical transport model

    Science.gov (United States)

    Kinnison, D. E.; Brasseur, G. P.; Walters, S.; Garcia, R. R.; Marsh, D. R.; Sassi, F.; Harvey, V. L.; Randall, C. E.; Emmons, L.; Lamarque, J. F.; Hess, P.; Orlando, J. J.; Tie, X. X.; Randel, W.; Pan, L. L.; Gettelman, A.; Granier, C.; Diehl, T.; Niemeier, U.; Simmons, A. J.

    2007-10-01

    The Model for Ozone and Related Chemical Tracers, version 3 (MOZART-3), which represents the chemical and physical processes from the troposphere through the lower mesosphere, was used to evaluate the representation of long-lived tracers and ozone using three different meteorological fields. The meteorological fields are based on (1) the Whole Atmosphere Community Climate Model, version 1b (WACCM1b), (2) the European Centre for Medium-Range Weather Forecasts (ECMWF) operational analysis, and (3) a new reanalysis for year 2000 from ECMWF called EXP471. Model-derived tracers (methane, water vapor, and total inorganic nitrogen) and ozone are compared to data climatologies from satellites. Model mean age of air was also derived and compared to in situ CO2 and SF6 data. A detailed analysis of the chemical fields simulated by MOZART-3 shows that even though the general features characterizing the three dynamical sets are rather similar, slight differences in winds and temperature can produce substantial differences in the calculated distributions of chemical tracers. The MOZART-3 simulations that use meteorological fields from WACCM1b and ECMWF EXP471 represented best the distribution of long-lived tracers and mean age of air in the stratosphere. There was a significant improvement using the ECMWF EXP471 reanalysis data product over the ECMWF operational data product. The effect of the quasi-biennial oscillation circulation on long-lived tracers and ozone is examined.

  2. A multimedia fate and chemical transport modeling system for pesticides: II. Model evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Li Rong; Yang Fuquan; Sloan, James J [Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON, N2L 3G1 (Canada); Trevor Scholtz, M, E-mail: sloanj@connect.uwaterloo.ca [ORTECH Environmental, 2395 Speakman Drive, Mississauga, ON, L5K 1B3 (Canada)

    2011-07-15

    Pesticides have adverse health effects and can be transported over long distances to contaminate sensitive ecosystems. To address problems caused by environmental pesticides we developed a multimedia multi-pollutant modeling system, and here we present an evaluation of the model by comparing modeled results against measurements. The modeled toxaphene air concentrations for two sites, in Louisiana (LA) and Michigan (MI), are in good agreement with measurements (average concentrations agree to within a factor of 2). Because the residue inventory showed no soil residues at these two sites, resulting in no emissions, the concentrations must be caused by transport; the good agreement between the modeled and measured concentrations suggests that the model simulates atmospheric transport accurately. Compared to the LA and MI sites, the measured air concentrations at two other sites having toxaphene soil residues leading to emissions, in Indiana and Arkansas, showed more pronounced seasonal variability (higher in warmer months); this pattern was also captured by the model. The model-predicted toxaphene concentration fraction on particles (0.5-5%) agrees well with measurement-based estimates (3% or 6%). There is also good agreement between modeled and measured dry (1:1) and wet (within a factor of less than 2) depositions in Lake Ontario. Additionally this study identified erroneous soil residue data around a site in Texas in a published US toxaphene residue inventory, which led to very low modeled air concentrations at this site. Except for the erroneous soil residue data around this site, the good agreement between the modeled and observed results implies that both the US and Mexican toxaphene soil residue inventories are reasonably good. This agreement also suggests that the modeling system is capable of simulating the important physical and chemical processes in the multimedia compartments.

  3. Understanding Business Models in Health Care.

    Science.gov (United States)

    Sharan, Alok D; Schroeder, Gregory D; West, Michael E; Vaccaro, Alexander R

    2016-05-01

    The increasing focus on the costs of care is forcing health care organizations to critically look at their basic set of processes and activities, to determine what type of value they can deliver. A business model describes the resources, processes, and cost assumptions that an organization makes that will lead to the delivery of a unique value proposition to a customer. As health care organizations are beginning to transform their structure in preparation for a value-based delivery system, understanding business model theory can help in the redesign process.

  4. Modelling of variability of the chemically peculiar star phi Draconis

    CERN Document Server

    Prvák, Milan; Krtička, Jiří; Mikulášek, Zdeněk; Lüftinger, T

    2015-01-01

    Context: The presence of heavier chemical elements in stellar atmospheres influences the spectral energy distribution (SED) of stars. An uneven surface distribution of these elements, together with flux redistribution and stellar rotation, are commonly believed to be the primary causes of the variability of chemically peculiar (CP) stars. Aims: We aim to model the photometric variability of the CP star PHI Dra based on the assumption of inhomogeneous surface distribution of heavier elements and compare it to the observed variability of the star. We also intend to identify the processes that contribute most significantly to its photometric variability. Methods: We use a grid of TLUSTY model atmospheres and the SYNSPEC code to model the radiative flux emerging from the individual surface elements of PHI Dra with different chemical compositions. We integrate the emerging flux over the visible surface of the star at different phases throughout the entire rotational period to synthesise theoretical light curves of...

  5. CHEMICAL REACTIONS SIMULATED BY GROUND-WATER-QUALITY MODELS.

    Science.gov (United States)

    Grove, David B.; Stollenwerk, Kenneth G.

    1987-01-01

    Recent literature concerning the modeling of chemical reactions during transport in ground water is examined with emphasis on sorption reactions. The theory of transport and reactions in porous media has been well documented. Numerous equations have been developed from this theory, to provide both continuous and sequential or multistep models, with the water phase considered for both mobile and immobile phases. Chemical reactions can be either equilibrium or non-equilibrium, and can be quantified in linear or non-linear mathematical forms. Non-equilibrium reactions can be separated into kinetic and diffusional rate-limiting mechanisms. Solutions to the equations are available by either analytical expressions or numerical techniques. Saturated and unsaturated batch, column, and field studies are discussed with one-dimensional, laboratory-column experiments predominating. A summary table is presented that references the various kinds of models studied and their applications in predicting chemical concentrations in ground waters.

  6. Asian Implications of Aflatoxin and Dioxin Foodborne Chemical Exposures Based on World Health Organization Estimates

    Directory of Open Access Journals (Sweden)

    Herman Gibb

    2015-12-01

    Full Text Available All people need food. Unsafe foods; however, may cause diseases ranging from diarrhea to cancer. Chemicals in food are a worldwide health concern. In 2006, the World Health Organization (WHO organized a consultation on the global burden of foodborne diseases. Work to estimate this burden began in 2007 and was carried out by the WHO Foodborne Disease Burden Epidemiology Reference Group (FERG, which included a Chemical and Toxins Disease Task Force. The results of 8 years of work were released in December 2015.

  7. Nahoon: Time-dependent gas-phase chemical model

    Science.gov (United States)

    Wakelam, V.

    2014-09-01

    Nahoon is a gas-phase chemical model that computes the chemical evolution in a 1D temperature and density structure. It uses chemical networks downloaded from the KInetic Database for Astrochemistry (KIDA) but the model can be adapted to any network. The program is written in Fortran 90 and uses the DLSODES (double precision) solver from the ODEPACK package to solve the coupled stiff differential equations. The solver computes the chemical evolution of gas-phase species at a fixed temperature and density and can be used in one dimension (1D) if a grid of temperature, density, and visual extinction is provided. Grains, both neutral and negatively charged, and electrons are considered as chemical species and their concentrations are computed at the same time as those of the other species. Nahoon contains a test to check the temperature range of the validity of the rate coefficients and avoid extrapolations outside this range. A test is also included to check for duplication of chemical reactions, defined over complementary ranges of temperature.

  8. A model for chemically-induced mechanical loading on MEMS

    DEFF Research Database (Denmark)

    Amiot, Fabien

    2007-01-01

    The development of full displacement field measurements as an alternative to the optical lever technique to measure the mechanical response for microelectro-mechanical systems components in their environment calls for a modeling of chemically-induced mechanical fields (stress, strain, and displac......The development of full displacement field measurements as an alternative to the optical lever technique to measure the mechanical response for microelectro-mechanical systems components in their environment calls for a modeling of chemically-induced mechanical fields (stress, strain...

  9. Combined physical and chemical nonequilibrium transport model for solution conduits.

    Science.gov (United States)

    Field, Malcolm S; Leij, Feike J

    2014-02-01

    Solute transport in karst aquifers is primarily constrained to relatively complex and inaccessible solution conduits where transport is often rapid, turbulent, and at times constrictive. Breakthrough curves generated from tracer tests in solution conduits are typically positively-skewed with long tails evident. Physical nonequilibrium models to fit breakthrough curves for tracer tests in solution conduits are now routinely employed. Chemical nonequilibrium processes are likely important interactions, however. In addition to partitioning between different flow domains, there may also be equilibrium and nonequilibrium partitioning between the aqueous and solid phases. A combined physical and chemical nonequilibrium (PCNE) model was developed for an instantaneous release similar to that developed by Leij and Bradford (2009) for a pulse release. The PCNE model allows for partitioning open space in solution conduits into mobile and immobile flow regions with first-order mass transfer between the two regions to represent physical nonequilibrium in the conduit. Partitioning between the aqueous and solid phases proceeds either as an equilibrium process or as a first-order process and represents chemical nonequilibrium for both the mobile and immobile regions. Application of the model to three example breakthrough curves demonstrates the applicability of the combined physical and chemical nonequilibrium model to tracer tests conducted in karst aquifers, with exceptionally good model fits to the data. The three models, each from a different state in the United States, exhibit very different velocities, dispersions, and other transport properties with most of the transport occurring via the fraction of mobile water. Fitting the model suggests the potentially important interaction of physical and chemical nonequilibrium processes.

  10. Towards validating use of self reported health (SRH) for community-based studies: Impact of environmental chemicals, sociodemographic variables, depression, and clinical indicators of health and nutrition

    Science.gov (United States)

    Environmental health impact assessment (HIA) studies, should consider social, behavioral, nutritional, dietary, environmental exposure and health risk factors at both the individual and community levels. Chemicals measured in blood or urine are often evaluated in relation to one ...

  11. Co-Exposure with Fullerene May Strengthen Health Effects of Organic Industrial Chemicals

    DEFF Research Database (Denmark)

    Lehto, M.; Karilainen, T.; Rog, T.;

    2014-01-01

    In vitro toxicological studies together with atomistic molecular dynamics simulations show that occupational co-exposure with C-60 fullerene may strengthen the health effects of organic industrial chemicals. The chemicals studied are acetophenone, benzaldehyde, benzyl alcohol, m-cresol, and toluene...... which can be used with fullerene as reagents or solvents in industrial processes. Potential co-exposure scenarios include a fullerene dust and organic chemical vapor, or a fullerene solution aerosolized in workplace air. Unfiltered and filtered mixtures of C-60 and organic chemicals represent different...... co-exposure scenarios in in vitro studies where acute cytotoxicity and immunotoxicity of C-60 and organic chemicals are tested together and alone by using human THP-1-derived macrophages. Statistically significant co-effects are observed for an unfiltered mixture of benzaldehyde and C-60 that is more...

  12. Upper Secondary Teachers' Knowledge for Teaching Chemical Bonding Models

    Science.gov (United States)

    Bergqvist, Anna; Drechsler, Michal; Rundgren, Shu-Nu Chang

    2016-01-01

    Researchers have shown a growing interest in science teachers' professional knowledge in recent decades. The article focuses on how chemistry teachers impart chemical bonding, one of the most important topics covered in upper secondary school chemistry courses. Chemical bonding is primarily taught using models, which are key for understanding science. However, many studies have determined that the use of models in science education can contribute to students' difficulties understanding the topic, and that students generally find chemical bonding a challenging topic. The aim of this study is to investigate teachers' knowledge of teaching chemical bonding. The study focuses on three essential components of pedagogical content knowledge (PCK): (1) the students' understanding, (2) representations, and (3) instructional strategies. We analyzed lesson plans about chemical bonding generated by 10 chemistry teachers with whom we also conducted semi-structured interviews about their teaching. Our results revealed that the teachers were generally unaware of how the representations of models they used affected student comprehension. The teachers had trouble specifying students' difficulties in understanding. Moreover, most of the instructional strategies described were generic and insufficient for promoting student understanding. Additionally, the teachers' rationale for choosing a specific representation or activity was seldom directed at addressing students' understanding. Our results indicate that both PCK components require improvement, and suggest that the two components should be connected. Implications for the professional development of pre-service and in-service teachers are discussed.

  13. Multilevel modelling and public health policy

    NARCIS (Netherlands)

    Leyland, Alastair H.; Groenewegen, Peter P.

    2003-01-01

    Background: Multilevel modelling is a statistical technique that extends ordinary regression analysis to the situation where the data are hierarchical. Such data form an increasingly common evidence base for public health policy, and as such it is important that policy makers should be aware of this

  14. Multilevel modelling and public health policy.

    NARCIS (Netherlands)

    Leyland, A.H.; Groenewegen, P.P.

    2003-01-01

    BACKGROUND: Multilevel modelling is a statistical technique that extends ordinary regression analysis to the situation where the data are hierarchical. Such data form an increasingly common evidence base for public health policy, and as such it is important that policy makers should be aware of this

  15. Modeling Exposure to Persistent Chemicals in Hazard and Risk Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Cowan-Ellsberry, Christina E.; McLachlan, Michael S.; Arnot, Jon A.; MacLeod, Matthew; McKone, Thomas E.; Wania, Frank

    2008-11-01

    Fate and exposure modeling has not thus far been explicitly used in the risk profile documents prepared to evaluate significant adverse effect of candidate chemicals for either the Stockholm Convention or the Convention on Long-Range Transboundary Air Pollution. However, we believe models have considerable potential to improve the risk profiles. Fate and exposure models are already used routinely in other similar regulatory applications to inform decisions, and they have been instrumental in building our current understanding of the fate of POP and PBT chemicals in the environment. The goal of this paper is to motivate the use of fate and exposure models in preparing risk profiles in the POP assessment procedure by providing strategies for incorporating and using models. The ways that fate and exposure models can be used to improve and inform the development of risk profiles include: (1) Benchmarking the ratio of exposure and emissions of candidate chemicals to the same ratio for known POPs, thereby opening the possibility of combining this ratio with the relative emissions and relative toxicity to arrive at a measure of relative risk. (2) Directly estimating the exposure of the environment, biota and humans to provide information to complement measurements, or where measurements are not available or are limited. (3) To identify the key processes and chemical and/or environmental parameters that determine the exposure; thereby allowing the effective prioritization of research or measurements to improve the risk profile. (4) Predicting future time trends including how quickly exposure levels in remote areas would respond to reductions in emissions. Currently there is no standardized consensus model for use in the risk profile context. Therefore, to choose the appropriate model the risk profile developer must evaluate how appropriate an existing model is for a specific setting and whether the assumptions and input data are relevant in the context of the application

  16. On matrix model partition functions for QCD with chemical potential

    CERN Document Server

    Akemann, G; Vernizzi, G

    2004-01-01

    Partition functions of two different matrix models for QCD with chemical potential are computed for an arbitrary number of quark and complex conjugate anti-quark flavors. In the large-N limit of weak nonhermiticity complete agreement is found between the two models. This supports the universality of such fermionic partition functions, that is of products of characteristic polynomials in the complex plane. In the strong nonhermiticity limit agreement is found for an equal number of quark and conjugate flavours. For a general flavor content the equality of partition functions holds only for small chemical potential. The chiral phase transition is analyzed for an arbitrary number of quarks, where the free energy presents a discontinuity of first order at a critical chemical potential. In the case of nondegenerate flavors there is first order phase transition for each separate mass scale.

  17. Bayesian inference of chemical kinetic models from proposed reactions

    KAUST Repository

    Galagali, Nikhil

    2015-02-01

    © 2014 Elsevier Ltd. Bayesian inference provides a natural framework for combining experimental data with prior knowledge to develop chemical kinetic models and quantify the associated uncertainties, not only in parameter values but also in model structure. Most existing applications of Bayesian model selection methods to chemical kinetics have been limited to comparisons among a small set of models, however. The significant computational cost of evaluating posterior model probabilities renders traditional Bayesian methods infeasible when the model space becomes large. We present a new framework for tractable Bayesian model inference and uncertainty quantification using a large number of systematically generated model hypotheses. The approach involves imposing point-mass mixture priors over rate constants and exploring the resulting posterior distribution using an adaptive Markov chain Monte Carlo method. The posterior samples are used to identify plausible models, to quantify rate constant uncertainties, and to extract key diagnostic information about model structure-such as the reactions and operating pathways most strongly supported by the data. We provide numerical demonstrations of the proposed framework by inferring kinetic models for catalytic steam and dry reforming of methane using available experimental data.

  18. A Rat α-Fetoprotein Binding Activity Prediction Model to Facilitate Assessment of the Endocrine Disruption Potential of Environmental Chemicals

    Directory of Open Access Journals (Sweden)

    Huixiao Hong

    2016-03-01

    Full Text Available Endocrine disruptors such as polychlorinated biphenyls (PCBs, diethylstilbestrol (DES and dichlorodiphenyltrichloroethane (DDT are agents that interfere with the endocrine system and cause adverse health effects. Huge public health concern about endocrine disruptors has arisen. One of the mechanisms of endocrine disruption is through binding of endocrine disruptors with the hormone receptors in the target cells. Entrance of endocrine disruptors into target cells is the precondition of endocrine disruption. The binding capability of a chemical with proteins in the blood affects its entrance into the target cells and, thus, is very informative for the assessment of potential endocrine disruption of chemicals. α-fetoprotein is one of the major serum proteins that binds to a variety of chemicals such as estrogens. To better facilitate assessment of endocrine disruption of environmental chemicals, we developed a model for α-fetoprotein binding activity prediction using the novel pattern recognition method (Decision Forest and the molecular descriptors calculated from two-dimensional structures by Mold2 software. The predictive capability of the model has been evaluated through internal validation using 125 training chemicals (average balanced accuracy of 69% and external validations using 22 chemicals (balanced accuracy of 71%. Prediction confidence analysis revealed the model performed much better at high prediction confidence. Our results indicate that the model is useful (when predictions are in high confidence in endocrine disruption risk assessment of environmental chemicals though improvement by increasing number of training chemicals is needed.

  19. A Rat α-Fetoprotein Binding Activity Prediction Model to Facilitate Assessment of the Endocrine Disruption Potential of Environmental Chemicals.

    Science.gov (United States)

    Hong, Huixiao; Shen, Jie; Ng, Hui Wen; Sakkiah, Sugunadevi; Ye, Hao; Ge, Weigong; Gong, Ping; Xiao, Wenming; Tong, Weida

    2016-03-25

    Endocrine disruptors such as polychlorinated biphenyls (PCBs), diethylstilbestrol (DES) and dichlorodiphenyltrichloroethane (DDT) are agents that interfere with the endocrine system and cause adverse health effects. Huge public health concern about endocrine disruptors has arisen. One of the mechanisms of endocrine disruption is through binding of endocrine disruptors with the hormone receptors in the target cells. Entrance of endocrine disruptors into target cells is the precondition of endocrine disruption. The binding capability of a chemical with proteins in the blood affects its entrance into the target cells and, thus, is very informative for the assessment of potential endocrine disruption of chemicals. α-fetoprotein is one of the major serum proteins that binds to a variety of chemicals such as estrogens. To better facilitate assessment of endocrine disruption of environmental chemicals, we developed a model for α-fetoprotein binding activity prediction using the novel pattern recognition method (Decision Forest) and the molecular descriptors calculated from two-dimensional structures by Mold² software. The predictive capability of the model has been evaluated through internal validation using 125 training chemicals (average balanced accuracy of 69%) and external validations using 22 chemicals (balanced accuracy of 71%). Prediction confidence analysis revealed the model performed much better at high prediction confidence. Our results indicate that the model is useful (when predictions are in high confidence) in endocrine disruption risk assessment of environmental chemicals though improvement by increasing number of training chemicals is needed.

  20. Model Based Monitoring and Control of Chemical and Biochemical Processes

    DEFF Research Database (Denmark)

    Huusom, Jakob Kjøbsted

    This presentation will give an overview of the work performed at the department of Chemical and Biochemical Engineering related to process control. A research vision is formulated and related to a number of active projects at the department. In more detail a project describing model estimation...

  1. Automated Physico-Chemical Cell Model Development through Information Theory

    Energy Technology Data Exchange (ETDEWEB)

    Peter J. Ortoleva

    2005-11-29

    The objective of this project was to develop predictive models of the chemical responses of microbial cells to variations in their surroundings. The application of these models is optimization of environmental remediation and energy-producing biotechnical processes.The principles on which our project is based are as follows: chemical thermodynamics and kinetics; automation of calibration through information theory; integration of multiplex data (e.g. cDNA microarrays, NMR, proteomics), cell modeling, and bifurcation theory to overcome cellular complexity; and the use of multiplex data and information theory to calibrate and run an incomplete model. In this report we review four papers summarizing key findings and a web-enabled, multiple module workflow we have implemented that consists of a set of interoperable systems biology computational modules.

  2. The Coupled Chemical and Physical Dynamics Model of MALDI

    Science.gov (United States)

    Knochenmuss, Richard

    2016-06-01

    The coupled physical and chemical dynamics model of ultraviolet matrix-assisted laser desorption/ionization (MALDI) has reproduced and explained a wide variety of MALDI phenomena. The rationale behind and elements of the model are reviewed, including the photophysics, kinetics, and thermodynamics of primary and secondary reaction steps. Experimental results are compared with model predictions to illustrate the foundations of the model, coupling of ablation and ionization, differences between and commonalities of matrices, secondary charge transfer reactions, ionization in both polarities, fluence and concentration dependencies, and suppression and enhancement effects.

  3. Influence of environmental chemicals on epigenetic programming and its applicability in human health risk assessment.

    Science.gov (United States)

    The field of epigenetics is rapidly evolving in response to the growing concern that heritable changes in gene expression may be involved in chemically-mediated adverse health outcomes, such as cancer. Although human and animal studies have shown a strong involvement of epigeneti...

  4. Computer-Aided Multiscale Modelling for Chemical Process Engineering

    DEFF Research Database (Denmark)

    Morales Rodriguez, Ricardo; Gani, Rafiqul

    2007-01-01

    T) for model translation, analysis and solution. The integration of ModDev, MoT and ICAS or any other external software or process simulator (using COM-Objects) permits the generation of different models and/or process configurations for purposes of simulation, design and analysis. Consequently, it is possible......Chemical processes are generally modeled through monoscale approaches, which, while not adequate, satisfy a useful role in product-process design. In this case, use of a multi-dimensional and multi-scale model-based approach has importance in product-process development. A computer-aided framework...... for model generation, analysis, solution and implementation is necessary for the development and application of the desired model-based approach for product-centric process design/analysis. This goal is achieved through the combination of a system for model development (ModDev), and a modelling tool (Mo...

  5. Evaluation of Artificial Intelligence Based Models for Chemical Biodegradability Prediction

    Directory of Open Access Journals (Sweden)

    Aleksandar Sabljic

    2004-12-01

    Full Text Available This study presents a review of biodegradability modeling efforts including a detailed assessment of two models developed using an artificial intelligence based methodology. Validation results for these models using an independent, quality reviewed database, demonstrate that the models perform well when compared to another commonly used biodegradability model, against the same data. The ability of models induced by an artificial intelligence methodology to accommodate complex interactions in detailed systems, and the demonstrated reliability of the approach evaluated by this study, indicate that the methodology may have application in broadening the scope of biodegradability models. Given adequate data for biodegradability of chemicals under environmental conditions, this may allow for the development of future models that include such things as surface interface impacts on biodegradability for example.

  6. Co-exposure with fullerene may strengthen health effects of organic industrial chemicals.

    Directory of Open Access Journals (Sweden)

    Maili Lehto

    Full Text Available In vitro toxicological studies together with atomistic molecular dynamics simulations show that occupational co-exposure with C60 fullerene may strengthen the health effects of organic industrial chemicals. The chemicals studied are acetophenone, benzaldehyde, benzyl alcohol, m-cresol, and toluene which can be used with fullerene as reagents or solvents in industrial processes. Potential co-exposure scenarios include a fullerene dust and organic chemical vapor, or a fullerene solution aerosolized in workplace air. Unfiltered and filtered mixtures of C60 and organic chemicals represent different co-exposure scenarios in in vitro studies where acute cytotoxicity and immunotoxicity of C60 and organic chemicals are tested together and alone by using human THP-1-derived macrophages. Statistically significant co-effects are observed for an unfiltered mixture of benzaldehyde and C60 that is more cytotoxic than benzaldehyde alone, and for a filtered mixture of m-cresol and C60 that is slightly less cytotoxic than m-cresol. Hydrophobicity of chemicals correlates with co-effects when secretion of pro-inflammatory cytokines IL-1β and TNF-α is considered. Complementary atomistic molecular dynamics simulations reveal that C60 co-aggregates with all chemicals in aqueous environment. Stable aggregates have a fullerene-rich core and a chemical-rich surface layer, and while essentially all C60 molecules aggregate together, a portion of organic molecules remains in water.

  7. Bridging the gap between academic research and regulatory health risk assessment of Endocrine Disrupting Chemicals.

    Science.gov (United States)

    Beronius, Anna; Hanberg, Annika; Zilliacus, Johanna; Rudén, Christina

    2014-12-01

    Regulatory risk assessment is traditionally based primarily on toxicity studies conducted according to standardized and internationally validated test guidelines. However, health risk assessment of endocrine disrupting chemicals (EDCs) is argued to rely on the efficient integration of findings from academic research. The aim of this review was to provide an overview of current developments to facilitate the use of academic research in regulatory risk assessment of chemicals and how certain aspects of study design and reporting are particularly important for the risk assessment process. By bridging the gap between academic research and regulatory health risk assessment of EDCs, scientific uncertainty in risk assessment conclusions can be reduced, allowing for better targeted policy decisions for chemical risk reduction.

  8. Hydration of Portoguese cements, measurement and modelling of chemical shrinkage

    DEFF Research Database (Denmark)

    Maia, Lino; Geiker, Mette Rica; Figueiras, Joaquim A.

    2008-01-01

    form of the dispersion model. The development of hydration varied between the investigated cements; based on the measured data the degree of hydration after 24 h hydration at 20 C varied between 40 and 50%. This should be taken into account when comparing properties of concrete made from the different......Development of cement hydration was studied by measuring the chemical shrinkage of pastes. Five types of Portuguese Portland cement were used in cement pastes with . Chemical shrinkage was measured by gravimetry and dilatometry. In gravimeters results were recorded automatically during at least...

  9. Improving Global Health Education: Development of a Global Health Competency Model

    Science.gov (United States)

    Ablah, Elizabeth; Biberman, Dorothy A.; Weist, Elizabeth M.; Buekens, Pierre; Bentley, Margaret E.; Burke, Donald; Finnegan, John R.; Flahault, Antoine; Frenk, Julio; Gotsch, Audrey R.; Klag, Michael J.; Lopez, Mario Henry Rodriguez; Nasca, Philip; Shortell, Stephen; Spencer, Harrison C.

    2014-01-01

    Although global health is a recommended content area for the future of education in public health, no standardized global health competency model existed for master-level public health students. Without such a competency model, academic institutions are challenged to ensure that students are able to demonstrate the knowledge, skills, and attitudes (KSAs) needed for successful performance in today's global health workforce. The Association of Schools of Public Health (ASPH) sought to address this need by facilitating the development of a global health competency model through a multistage modified-Delphi process. Practitioners and academic global health experts provided leadership and guidance throughout the competency development process. The resulting product, the Global Health Competency Model 1.1, includes seven domains and 36 competencies. The Global Health Competency Model 1.1 provides a platform for engaging educators, students, and global health employers in discussion of the KSAs needed to improve human health on a global scale. PMID:24445206

  10. Review of existing terrestrial bioaccumulation models and terrestrial bioaccumulation modeling needs for organic chemicals

    Science.gov (United States)

    Protocols for terrestrial bioaccumulation assessments are far less-developed than for aquatic systems. This manuscript reviews modeling approaches that can be used to assess the terrestrial bioaccumulation potential of commercial organic chemicals. Models exist for plant, inver...

  11. Modeling Warfare in Social Animals: A "Chemical" Approach

    Science.gov (United States)

    Santarlasci, Alisa; Martelloni, Gianluca; Frizzi, Filippo; Santini, Giacomo; Bagnoli, Franco

    2014-01-01

    We present here a general method for modelling the dynamics of battles among social animals. The proposed method exploits the procedures widely used to model chemical reactions, but still uncommon in behavioural studies. We applied this methodology to the interpretation of experimental observations of battles between two species of ants (Lasius neglectus and Lasius paralienus), but this scheme may have a wider applicability and can be extended to other species as well. We performed two types of experiment labelled as interaction and mortality. The interaction experiments are designed to obtain information on the combat dynamics and lasted one hour. The mortality ones provide information on the casualty rates of the two species and lasted five hours. We modelled the interactions among ants using a chemical model which considers the single ant individuals and fighting groups analogously to atoms and molecules. The mean-field behaviour of the model is described by a set of non-linear differential equations. We also performed stochastic simulations of the corresponding agent-based model by means of the Gillespie event-driven integration scheme. By fitting the stochastic trajectories with the deterministic model, we obtained the probability distribution of the reaction parameters. The main result that we obtained is a dominance phase diagram, that gives the average trajectory of a generic battle, for an arbitrary number of opponents. This phase diagram was validated with some extra experiments. With respect to other war models (e.g., Lanchester's ones), our chemical model considers all phases of the battle and not only casualties. This allows a more detailed description of the battle (with a larger number of parameters), allowing the development of more sophisticated models (e.g., spatial ones), with the goal of distinguishing collective effects from the strategic ones. PMID:25369269

  12. SDG-based Model Validation in Chemical Process Simulation

    Institute of Scientific and Technical Information of China (English)

    张贝克; 许欣; 马昕; 吴重光

    2013-01-01

    Signed direct graph (SDG) theory provides algorithms and methods that can be applied directly to chemical process modeling and analysis to validate simulation models, and is a basis for the development of a soft-ware environment that can automate the validation activity. This paper is concentrated on the pretreatment of the model validation. We use the validation scenarios and standard sequences generated by well-established SDG model to validate the trends fitted from the simulation model. The results are helpful to find potential problems, as-sess possible bugs in the simulation model and solve the problem effectively. A case study on a simulation model of boiler is presented to demonstrate the effectiveness of this method.

  13. Property Modelling for Applications in Chemical Product and Process Design

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    , polymers, mixtures as well as separation processes. The presentation will highlight the framework (ICAS software) for property modeling, the property models and issues such as prediction accuracy, flexibility, maintenance and updating of the database. Also, application issues related to the use of property......, they are not always available. Also, it may be too expensive to measure them or it may take too much time. In these situations and when repetitive calculations are involved (as in process simulation), it is useful to have appropriate models to reliably predict the needed properties. A collection of methods tools...... such as database, property model library, model parameter regression, and, property-model based product-process design will be presented. The database contains pure component and mixture data for a wide range of organic chemicals. The property models are based on the combined group contribution and atom...

  14. Nonlocal Nambu-Jona-Lasinio model and chiral chemical potential

    CERN Document Server

    Frasca, Marco

    2016-01-01

    We derive the critical temperature in a nonlocal Nambu-Jona-Lasinio model with the presence of a chiral chemical potential. The model we consider uses a form factor derived from recent studies of the gluon propagator in Yang-Mills theory and has the property to fit in excellent way the form factor arising from the instanton liquid picture for the vacuum of the theory. Nambu-Jona-Lasinio model is derived form quantum chromodynamics providing all the constants of the theory without any need for fits. We show that the critical temperature in this case always exists and increases as the square of the chiral chemical potential. The expression we obtain for the critical temperature depends on the mass gap that naturally arises from Yang-Mills theory at low-energy as also confirmed by lattice computations.

  15. The chemical bond in inorganic chemistry the bond valence model

    CERN Document Server

    Brown, I David

    2016-01-01

    The bond valence model is a version of the ionic model in which the chemical constraints are expressed in terms of localized chemical bonds formed by the valence charge of the atoms. Theorems derived from the properties of the electrostatic flux predict the rules obeyed by both ionic and covalent bonds. They make quantitative predictions of coordination number, crystal structure, bond lengths and bond angles. Bond stability depends on the matching of the bonding strengths of the atoms, while the conflicting requirements of chemistry and space lead to the structural instabilities responsible for the unusual physical properties displayed by some materials. The model has applications in many fields ranging from mineralogy to molecular biology.

  16. Aesthetics of Chemical Products: Materials, Molecules, and Molecular Models

    Directory of Open Access Journals (Sweden)

    Joachim Schummer

    2003-03-01

    Full Text Available By comparing chemistry to art, chemists have recently made claims to the aesthetic value, even beauty, of some of their products. This paper takes these claims seriously and turns them into a systematic investigation of the aesthetics of chemical products. I distinguish three types of chemical products - materials, molecules, and molecular models - and use a wide variety of aesthetic theories suitable for an investigation of the corresponding sorts of objects. These include aesthetics of materials, idealistic aesthetics from Plato to Kant and Schopenhauer, psychological approaches of Ernst Gombrich and Rudolf Arnheim, and semiotic aesthetics of Nelson Goodman and Umberto Eco. Although the investigation does not support recent claims, I point out where aesthetics does and can play an import role in chemistry. Particularly, Eco's approach helps us understand that and how aesthetic experience can be a driving force in chemical research.

  17. [Indoor air and human health--sick house syndrome and multiple chemical sensitivity].

    Science.gov (United States)

    Ando, Masanori

    2002-01-01

    The number of complaints about the quality of indoor air has increased during the past two decades. These complaints have been frequent enough that the term "Sick House Syndrome or Sick Building Syndrome" and "Multiple Chemical Sensitivity" has been coined. Complaints are likely related to the increased use of synthetic organic materials in house, furnishing, and consumer products; and the buildings, furnishings, and consumer products; and the decreased ventilation for energy conservation in homes. Approximately thousand volatile chemicals have been identified in indoor air. The main sources of these chemicals are house materials, combustion fumes, cleaning compounds, and paints or stains. Exposure to high levels of these emissions and to others, coupled with the fact that most people spend more time indoors than outdoors, raises the possibility that the risk to human health from indoor air pollution may be potentially greater than the risk posed from outdoor pollutants. The complaints most frequently voiced with respect to Sick House Syndrome are irritations of the eye, nose, and throat; cough and hoarseness of voice; headache and mental fatigue. The syndrome of multiple chemical sensitivities is controversial subject with increasing impact on the field of indoor air quality. The controversy surrounding Multiple Chemical Sensitivity includes its definition, theories of etiology and pathogenesis, diagnostic, and life style. Multiple Chemical Sensitivity is considered the hypothesis that is a disease caused by exposure to many chemically distinct environmental substances at very low.

  18. Chemical speciation of trace metals emitted from Indonesian peat fires for health risk assessment

    Science.gov (United States)

    Betha, Raghu; Pradani, Maharani; Lestari, Puji; Joshi, Umid Man; Reid, Jeffrey S.; Balasubramanian, Rajasekhar

    2013-03-01

    Regional smoke-induced haze in Southeast Asia, caused by uncontrolled forest and peat fires in Indonesia, is of major environmental and health concern. In this study, we estimated carcinogenic and non-carcinogenic health risk due to exposure to fine particles (PM2.5) as emitted from peat fires at Kalimantan, Indonesia. For the health risk analysis, chemical speciation (exchangeable, reducible, oxidizable, and residual fractions) of 12 trace metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Ti, V and Zn) in PM2.5 was studied. Results indicate that Al, Fe and Ti together accounted for a major fraction of total metal concentrations (~ 83%) in PM2.5 emissions in the immediate vicinity of peat fires. Chemical speciation reveals that a major proportion of most of the metals, with the exception of Cr, Mn, Fe, Ni and Cd, was present in the residual fraction. The exchangeable fraction of metals, which represents their bioavailability, could play a major role in inducing human health effects of PM2.5. This fraction contained carcinogenic metals such as Cd (39.2 ng m- 3) and Ni (249.3 ng m- 3) that exceeded their WHO guideline values by several factors. Health risk estimates suggest that exposure to PM2.5 emissions in the vicinity of peat fires poses serious health threats.

  19. Chemical domain of QSAR models from atom-centered fragments.

    Science.gov (United States)

    Kühne, Ralph; Ebert, Ralf-Uwe; Schüürmann, Gerrit

    2009-12-01

    A methodology to characterize the chemical domain of qualitative and quantitative structure-activity relationship (QSAR) models based on the atom-centered fragment (ACF) approach is introduced. ACFs decompose the molecule into structural pieces, with each non-hydrogen atom of the molecule acting as an ACF center. ACFs vary with respect to their size in terms of the path length covered in each bonding direction starting from a given central atom and how comprehensively the neighbor atoms (including hydrogen) are described in terms of element type and bonding environment. In addition to these different levels of ACF definitions, the ACF match mode as degree of strictness of the ACF comparison between a test compound and a given ACF pool (such as from a training set) has to be specified. Analyses of the prediction statistics of three QSAR models with their training sets as well as with external test sets and associated subsets demonstrate a clear relationship between the prediction performance and the levels of ACF definition and match mode. The findings suggest that second-order ACFs combined with a borderline match mode may serve as a generic and at the same time a mechanistically sound tool to define and evaluate the chemical domain of QSAR models. Moreover, four standard categories of the ACF-based membership to a given chemical domain (outside, borderline outside, borderline inside, inside) are introduced that provide more specific information about the expected QSAR prediction performance. As such, the ACF-based characterization of the chemical domain appears to be particularly useful for QSAR applications in the context of REACH and other regulatory schemes addressing the safety evaluation of chemical compounds.

  20. Modeling reservoir density underflow and interflow from a chemical spill

    Science.gov (United States)

    Gu, R.; McCutcheon, S.C.; Wang, P.-F.

    1996-01-01

    An integral simulation model has been developed for understanding and simulating the process of a density current and the transport of spilled chemicals in a stratified reservoir. The model is capable of describing flow behavior and mixing mechanisms in different flow regimes (plunging flow, underflow, and interflow). It computes flow rate, velocity, flow thickness, mixing parameterized by entrainment and dilution, depths of plunging, separation and intrusion, and time of travel. The model was applied to the Shasta Reservoir in northern California during the July 1991 Sacramento River chemical spill. The simulations were used to assist in the emergency response, confirm remediation measures, and guide data collection. Spill data that were available after the emergency response are used to conduct a postaudit of the model results. Predicted flow parameters are presented and compared with observed interflow intrusion depth, travel time, and measured concentrations of spilled chemicals. In the reservoir, temperature difference between incoming river flow and ambient lake water played a dominant role during the processes of flow plunging, separation, and intrusion. With the integral approach, the gross flow behavior can be adequately described and information useful in the analysis of contaminated flow in a reservoir after a spill is provided.

  1. 2-D Chemical-Dynamical Modeling of Venus's Sulfur Variability

    Science.gov (United States)

    Bierson, Carver J.; Zhang, Xi

    2016-10-01

    Over the last decade a combination of ground based and Venus Express observations have been made of the concentration of sulfur species in Venus's atmosphere, both above [1, 2] and below the clouds [3, 4]. These observations put constraints on both the vertical and meridional variations of the major sulfur species in Venus's atmosphere.. It has also been observed that SO2 concentrations varies on both timescales of hours and years [1,4]. The spatial and temporal distribution of tracer species is owing to two possibilities: mutual chemical interaction and dynamical tracer transport.Previous Chemical modeling of Venus's middle atmosphere has only been explored in 1-D. We will present the first 2-D (altitude and latitude) chemical-dynamical model for Venus's middle atmosphere. The sulfur chemistry is based on of the 1D model of Zhang et al. 2012 [5]. We do model runs over multiple Venus decades testing two scenarios: first one with varying sulfur fluxes from below, and second with secular dynamical perturbations in the atmosphere [6]. By comparing to Venus Express and ground based observations, we put constraints on the dynamics of Venus's middle atmosphere.References: [1] Belyaev et al. Icarus 2012 [2] Marcq et al. Nature geoscience, 2013 [3] Marcq et al. JGR:Planets, 2008 [4] Arney et al. JGR:Planets, 2014 [5] Zhang et al. Icarus 2012 [6] Parish et al. Icarus 2012

  2. Comparison of modeling approaches to prioritize chemicals based on estimates of exposure and exposure potential

    Science.gov (United States)

    Mitchell, Jade; Arnot, Jon A.; Jolliet, Olivier; Georgopoulos, Panos G.; Isukapalli, Sastry; Dasgupta, Surajit; Pandian, Muhilan; Wambaugh, John; Egeghy, Peter; Cohen Hubal, Elaine A.; Vallero, Daniel A.

    2014-01-01

    While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecological health outcomes. Recent improvements and advances such as high throughput data gathering, high performance computational capabilities, and predictive chemical inherency methodology make this an opportune time to develop an exposure-based prioritization approach that can systematically utilize and link the asymmetrical bodies of knowledge for hazard and exposure. In response to the US EPA’s need to develop novel approaches and tools for rapidly prioritizing chemicals, a “Challenge” was issued to several exposure model developers to aid the understanding of current systems in a broader sense and to assist the US EPA’s effort to develop an approach comparable to other international efforts. A common set of chemicals were prioritized under each current approach. The results are presented herein along with a comparative analysis of the rankings of the chemicals based on metrics of exposure potential or actual exposure estimates. The analysis illustrates the similarities and differences across the domains of information incorporated in each modeling approach. The overall findings indicate a need to reconcile exposures from diffuse, indirect sources (far-field) with exposures from directly, applied chemicals in consumer products or resulting from the presence of a chemical in a microenvironment like a home or vehicle. Additionally, the exposure scenario, including the mode of entry into the environment (i.e. through air, water or sediment) appears to be an important determinant of the level of agreement between modeling approaches. PMID:23707726

  3. Economic model predictive control theory, formulations and chemical process applications

    CERN Document Server

    Ellis, Matthew; Christofides, Panagiotis D

    2017-01-01

    This book presents general methods for the design of economic model predictive control (EMPC) systems for broad classes of nonlinear systems that address key theoretical and practical considerations including recursive feasibility, closed-loop stability, closed-loop performance, and computational efficiency. Specifically, the book proposes: Lyapunov-based EMPC methods for nonlinear systems; two-tier EMPC architectures that are highly computationally efficient; and EMPC schemes handling explicitly uncertainty, time-varying cost functions, time-delays and multiple-time-scale dynamics. The proposed methods employ a variety of tools ranging from nonlinear systems analysis, through Lyapunov-based control techniques to nonlinear dynamic optimization. The applicability and performance of the proposed methods are demonstrated through a number of chemical process examples. The book presents state-of-the-art methods for the design of economic model predictive control systems for chemical processes. In addition to being...

  4. Computer-Aided Construction of Chemical Kinetic Models

    Energy Technology Data Exchange (ETDEWEB)

    Green, William H. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2014-12-31

    The combustion chemistry of even simple fuels can be extremely complex, involving hundreds or thousands of kinetically significant species. The most reasonable way to deal with this complexity is to use a computer not only to numerically solve the kinetic model, but also to construct the kinetic model in the first place. Because these large models contain so many numerical parameters (e.g. rate coefficients, thermochemistry) one never has sufficient data to uniquely determine them all experimentally. Instead one must work in “predictive” mode, using theoretical rather than experimental values for many of the numbers in the model, and as appropriate refining the most sensitive numbers through experiments. Predictive chemical kinetics is exactly what is needed for computer-aided design of combustion systems based on proposed alternative fuels, particularly for early assessment of the value and viability of proposed new fuels before those fuels are commercially available. This project was aimed at making accurate predictive chemical kinetics practical; this is a challenging goal which requires a range of science advances. The project spanned a wide range from quantum chemical calculations on individual molecules and elementary-step reactions, through the development of improved rate/thermo calculation procedures, the creation of algorithms and software for constructing and solving kinetic simulations, the invention of methods for model-reduction while maintaining error control, and finally comparisons with experiment. Many of the parameters in the models were derived from quantum chemistry calculations, and the models were compared with experimental data measured in our lab or in collaboration with others.

  5. Combinatorial QSAR modeling of chemical toxicants tested against Tetrahymena pyriformis.

    Science.gov (United States)

    Zhu, Hao; Tropsha, Alexander; Fourches, Denis; Varnek, Alexandre; Papa, Ester; Gramatica, Paola; Oberg, Tomas; Dao, Phuong; Cherkasov, Artem; Tetko, Igor V

    2008-04-01

    Selecting most rigorous quantitative structure-activity relationship (QSAR) approaches is of great importance in the development of robust and predictive models of chemical toxicity. To address this issue in a systematic way, we have formed an international virtual collaboratory consisting of six independent groups with shared interests in computational chemical toxicology. We have compiled an aqueous toxicity data set containing 983 unique compounds tested in the same laboratory over a decade against Tetrahymena pyriformis. A modeling set including 644 compounds was selected randomly from the original set and distributed to all groups that used their own QSAR tools for model development. The remaining 339 compounds in the original set (external set I) as well as 110 additional compounds (external set II) published recently by the same laboratory (after this computational study was already in progress) were used as two independent validation sets to assess the external predictive power of individual models. In total, our virtual collaboratory has developed 15 different types of QSAR models of aquatic toxicity for the training set. The internal prediction accuracy for the modeling set ranged from 0.76 to 0.93 as measured by the leave-one-out cross-validation correlation coefficient ( Q abs2). The prediction accuracy for the external validation sets I and II ranged from 0.71 to 0.85 (linear regression coefficient R absI2) and from 0.38 to 0.83 (linear regression coefficient R absII2), respectively. The use of an applicability domain threshold implemented in most models generally improved the external prediction accuracy but at the same time led to a decrease in chemical space coverage. Finally, several consensus models were developed by averaging the predicted aquatic toxicity for every compound using all 15 models, with or without taking into account their respective applicability domains. We find that consensus models afford higher prediction accuracy for the

  6. Studies on modelling of bubble driven flows in chemical reactors

    Energy Technology Data Exchange (ETDEWEB)

    Grevskott, Sverre

    1997-12-31

    Multiphase reactors are widely used in the process industry, especially in the petrochemical industry. They very often are characterized by very good thermal control and high heat transfer coefficients against heating and cooling surfaces. This thesis first reviews recent advances in bubble column modelling, focusing on the fundamental flow equations, drag forces, transversal forces and added mass forces. The mathematical equations for the bubble column reactor are developed, using an Eulerian description for the continuous and dispersed phase in tensor notation. Conservation equations for mass, momentum, energy and chemical species are given, and the k-{epsilon} and Rice-Geary models for turbulence are described. The different algebraic solvers used in the model are described, as are relaxation procedures. Simulation results are presented and compared with experimental values. Attention is focused on the modelling of void fractions and gas velocities in the column. The energy conservation equation has been included in the bubble column model in order to model temperature distributions in a heated reactor. The conservation equation of chemical species has been included to simulate absorption of CO{sub 2}. Simulated axial and radial mass fraction profiles for CO{sub 2} in the gas phase are compared with measured values. Simulations of the dynamic behaviour of the column are also presented. 189 refs., 124 figs., 1 tab.

  7. Chemical modeling of water deuteration in IRAS16293-2422

    CERN Document Server

    Wakelam, V; Aikawa, Y; Coutens, A; Bottinelli, S; Caux, E

    2014-01-01

    IRAS 16293-2422 is a well studied low-mass protostar characterized by a strong level of deuterium fractionation. In the line of sight of the protostellar envelope, an additional absorption layer, rich in singly and doubly deuterated water has been discovered by a detailed multiline analysis of HDO. To model the chemistry in this source, the gas-grain chemical code Nautilus has been used with an extended deuterium network. For the protostellar envelope, we solve the chemical reaction network in infalling fluid parcels in a protostellar core model. For the foreground cloud, we explored several physical conditions (density, cosmic ionization rate, C/O ratio). The main results of the paper are that gas-phase abundances of H2O, HDO and D2O observed in the inner regions of IRAS16293-2422 are lower than those predicted by a 1D dynamical/chemical (hot corino) model in which the ices are fully evaporated. The abundance in the outer part of the envelope present chaotic profiles due to adsorption/evaporation competition...

  8. Probabilistic consequence model of accidenal or intentional chemical releases.

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Y.-S.; Samsa, M. E.; Folga, S. M.; Hartmann, H. M.

    2008-06-02

    In this work, general methodologies for evaluating the impacts of large-scale toxic chemical releases are proposed. The potential numbers of injuries and fatalities, the numbers of hospital beds, and the geographical areas rendered unusable during and some time after the occurrence and passage of a toxic plume are estimated on a probabilistic basis. To arrive at these estimates, historical accidental release data, maximum stored volumes, and meteorological data were used as inputs into the SLAB accidental chemical release model. Toxic gas footprints from the model were overlaid onto detailed population and hospital distribution data for a given region to estimate potential impacts. Output results are in the form of a generic statistical distribution of injuries and fatalities associated with specific toxic chemicals and regions of the United States. In addition, indoor hazards were estimated, so the model can provide contingency plans for either shelter-in-place or evacuation when an accident occurs. The stochastic distributions of injuries and fatalities are being used in a U.S. Department of Homeland Security-sponsored decision support system as source terms for a Monte Carlo simulation that evaluates potential measures for mitigating terrorist threats. This information can also be used to support the formulation of evacuation plans and to estimate damage and cleanup costs.

  9. Ensuring Adequate Health and Safety Information for Decision Makers during Large-Scale Chemical Releases

    Science.gov (United States)

    Petropoulos, Z.; Clavin, C.; Zuckerman, B.

    2015-12-01

    The 2014 4-Methylcyclohexanemethanol (MCHM) spill in the Elk River of West Virginia highlighted existing gaps in emergency planning for, and response to, large-scale chemical releases in the United States. The Emergency Planning and Community Right-to-Know Act requires that facilities with hazardous substances provide Material Safety Data Sheets (MSDSs), which contain health and safety information on the hazardous substances. The MSDS produced by Eastman Chemical Company, the manufacturer of MCHM, listed "no data available" for various human toxicity subcategories, such as reproductive toxicity and carcinogenicity. As a result of incomplete toxicity data, the public and media received conflicting messages on the safety of the contaminated water from government officials, industry, and the public health community. Two days after the governor lifted the ban on water use, the health department partially retracted the ban by warning pregnant women to continue avoiding the contaminated water, which the Centers for Disease Control and Prevention deemed safe three weeks later. The response in West Virginia represents a failure in risk communication and calls to question if government officials have sufficient information to support evidence-based decisions during future incidents. Research capabilities, like the National Science Foundation RAPID funding, can provide a solution to some of the data gaps, such as information on environmental fate in the case of the MCHM spill. In order to inform policy discussions on this issue, a methodology for assessing the outcomes of RAPID and similar National Institutes of Health grants in the context of emergency response is employed to examine the efficacy of research-based capabilities in enhancing public health decision making capacity. The results of this assessment highlight potential roles rapid scientific research can fill in ensuring adequate health and safety data is readily available for decision makers during large

  10. Regimes of chemical reaction waves initiated by nonuniform initial conditions for detailed chemical reaction models.

    Science.gov (United States)

    Liberman, M A; Kiverin, A D; Ivanov, M F

    2012-05-01

    Regimes of chemical reaction wave propagation initiated by initial temperature nonuniformity in gaseous mixtures, whose chemistry is governed by chain-branching kinetics, are studied using a multispecies transport model and a detailed chemical model. Possible regimes of reaction wave propagation are identified for stoichiometric hydrogen-oxygen and hydrogen-air mixtures in a wide range of initial pressures and temperature levels, depending on the initial non-uniformity steepness. The limits of the regimes of reaction wave propagation depend upon the values of the spontaneous wave speed and the characteristic velocities of the problem. It is shown that one-step kinetics cannot reproduce either quantitative neither qualitative features of the ignition process in real gaseous mixtures because the difference between the induction time and the time when the exothermic reaction begins significantly affects the ignition, evolution, and coupling of the spontaneous reaction wave and the pressure wave, especially at lower temperatures. We show that all the regimes initiated by the temperature gradient occur for much shallower temperature gradients than predicted by a one-step model. The difference is very large for lower initial pressures and for slowly reacting mixtures. In this way the paper provides an answer to questions, important in practice, about the ignition energy, its distribution, and the scale of the initial nonuniformity required for ignition in one or another regime of combustion wave propagation.

  11. The Instanton-Dyon Liquid Model III: Finite Chemical Potential

    CERN Document Server

    Liu, Yizhuang; Zahed, Ismail

    2016-01-01

    We discuss an extension of the instanton-dyon liquid model that includes light quarks at finite chemical potential in the center symmetric phase. We develop the model in details for the case of SU_c(2)\\times SU_f(2) by mapping the theory on a 3-dimensional quantum effective theory. We analyze the different phases in the mean-field approximation. We extend this analysis to the general case of SU_c(N_c)\\times SU_f(N_f) and note that the chiral and diquark pairings are always comparable.

  12. Multi-scale modeling for sustainable chemical production

    DEFF Research Database (Denmark)

    Zhuang, Kai; Bakshi, Bhavik R.; Herrgard, Markus

    2013-01-01

    With recent advances in metabolic engineering, it is now technically possible to produce a wide portfolio of existing petrochemical products from biomass feedstock. In recent years, a number of modeling approaches have been developed to support the engineering and decision-making processes......, chemical industry, economy, and ecosystem. In addition, we propose a multi-scale approach for integrating the existing models into a cohesive framework. The major benefit of this proposed framework is that the design and decision-making at each scale can be informed, guided, and constrained by simulations...

  13. Health Insurance, Medical Care, and Health Outcomes: A Model of Elderly Health Dynamics

    Science.gov (United States)

    Yang, Zhou; Gilleskie, Donna B.; Norton, Edward C.

    2009-01-01

    Prescription drug coverage creates a change in medical care consumption, beyond standard moral hazard, arising both from the differential cost-sharing and the relative effectiveness of different types of care. We model the dynamic supplemental health insurance decisions of Medicare beneficiaries, their medical care demand, and subsequent health…

  14. Modeling thermal/chemical/mechanical response of energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Baer, M.R.; Hobbs, M.L.; Gross, R.J. [and others

    1995-07-01

    An overview of modeling at Sandia National Laboratories is presented which describes coupled thermal, chemical and mechanical response of energetic materials. This modeling addresses cookoff scenarios for safety assessment studies in systems containing energetic materials. Foundation work is discussed which establishes a method for incorporating chemistry and mechanics into multidimensional analysis. Finite element analysis offers the capabilities to simultaneously resolve reactive heat transfer and structural mechanics in complex geometries. Nonlinear conduction heat transfer, with multiple step finite-rate chemistry, is resolved using a thermal finite element code. Rate equations are solved element-by-element using a modified matrix-free stiff solver This finite element software was developed for the simulation of systems requiring large numbers of finite elements. An iterative implicit scheme, based on the conjugate gradient method, is used and a hemi-cube algorithm is employed for the determination of view factors in surface-to-surface radiation transfer The critical link between the reactive heat transfer and mechanics is the introduction of an appropriate constitutive material model providing a stress-strain relationship for quasi-static mechanics analysis. This model is formally derived from bubble nucleation theory, and parameter variations of critical model parameters indicate that a small degree of decomposition leads to significant mechanical response. Coupled thermal/chemical/mechanical analysis is presented which simulates experiments designed to probe cookoff thermal-mechanical response of energetic materials.

  15. Modelling Chemical Reasoning to Predict and Invent Reactions.

    Science.gov (United States)

    Segler, Marwin H S; Waller, Mark P

    2016-11-11

    The ability to reason beyond established knowledge allows organic chemists to solve synthetic problems and invent novel transformations. Herein, we propose a model that mimics chemical reasoning, and formalises reaction prediction as finding missing links in a knowledge graph. We have constructed a knowledge graph containing 14.4 million molecules and 8.2 million binary reactions, which represents the bulk of all chemical reactions ever published in the scientific literature. Our model outperforms a rule-based expert system in the reaction prediction task for 180 000 randomly selected binary reactions. The data-driven model generalises even beyond known reaction types, and is thus capable of effectively (re-)discovering novel transformations (even including transition metal-catalysed reactions). Our model enables computers to infer hypotheses about reactivity and reactions by only considering the intrinsic local structure of the graph and because each single reaction prediction is typically achieved in a sub-second time frame, the model can be used as a high-throughput generator of reaction hypotheses for reaction discovery.

  16. Predictive Modeling of Chemical Hazard by Integrating Numerical Descriptors of Chemical Structures and Short-term Toxicity Assay Data

    Science.gov (United States)

    Rusyn, Ivan; Sedykh, Alexander; Guyton, Kathryn Z.; Tropsha, Alexander

    2012-01-01

    Quantitative structure-activity relationship (QSAR) models are widely used for in silico prediction of in vivo toxicity of drug candidates or environmental chemicals, adding value to candidate selection in drug development or in a search for less hazardous and more sustainable alternatives for chemicals in commerce. The development of traditional QSAR models is enabled by numerical descriptors representing the inherent chemical properties that can be easily defined for any number of molecules; however, traditional QSAR models often have limited predictive power due to the lack of data and complexity of in vivo endpoints. Although it has been indeed difficult to obtain experimentally derived toxicity data on a large number of chemicals in the past, the results of quantitative in vitro screening of thousands of environmental chemicals in hundreds of experimental systems are now available and continue to accumulate. In addition, publicly accessible toxicogenomics data collected on hundreds of chemicals provide another dimension of molecular information that is potentially useful for predictive toxicity modeling. These new characteristics of molecular bioactivity arising from short-term biological assays, i.e., in vitro screening and/or in vivo toxicogenomics data can now be exploited in combination with chemical structural information to generate hybrid QSAR–like quantitative models to predict human toxicity and carcinogenicity. Using several case studies, we illustrate the benefits of a hybrid modeling approach, namely improvements in the accuracy of models, enhanced interpretation of the most predictive features, and expanded applicability domain for wider chemical space coverage. PMID:22387746

  17. Overview of human health and chemical mixtures: problems facing developing countries.

    OpenAIRE

    2002-01-01

    In developing countries, chemical mixtures within the vicinity of small-scale enterprises, smelters, mines, agricultural areas, toxic waste disposal sites, etc., often present a health hazard to the populations within those vicinities. Therefore, in these countries, there is a need to study the toxicological effects of mixtures of metals, pesticides, and organic compounds. However, the study of mixtures containing substances such as DDT (dichlorodiphenyltrichloroethane, an insecticide banned ...

  18. Risk managment of complex aquifers contaminated by chemical mixtures : numerical tools and human health risk assessment

    OpenAIRE

    Henri, Christopher

    2015-01-01

    Human impact on groundwater resources has led to a rapid growth of social concerns worldwide owing to an increasing presence of toxic chemicals released in the subsurface. Risk assessment provides the scientific tool needed to quantify the actual thread that these potential hazards pose to human health. Specifically, risk analysis enables decision makers to answer: What can happen? How likely is it to happen? What can be the consequences? Risk assessment is in this context essential. However,...

  19. Modeling turbulence structure. Chemical kinetics interaction in turbulent reactive flows

    Energy Technology Data Exchange (ETDEWEB)

    Magnussen, B.F. [The Norwegian Univ. of Science and Technology, Trondheim (Norway)

    1997-12-31

    The challenge of the mathematical modelling is to transfer basic physical knowledge into a mathematical formulation such that this knowledge can be utilized in computational simulation of practical problems. The combustion phenomena can be subdivided into a large set of interconnected phenomena like flow, turbulence, thermodynamics, chemical kinetics, radiation, extinction, ignition etc. Combustion in one application differs from combustion in another area by the relative importance of the various phenomena. The difference in fuel, geometry and operational conditions often causes the differences. The computer offers the opportunity to treat the individual phenomena and their interactions by models with wide operational domains. The relative magnitude of the various phenomena therefore becomes the consequence of operational conditions and geometry and need not to be specified on the basis of experience for the given problem. In mathematical modelling of turbulent combustion, one of the big challenges is how to treat the interaction between the chemical reactions and the fluid flow i.e. the turbulence. Different scientists adhere to different concepts like the laminar flamelet approach, the pdf approach of the Eddy Dissipation Concept. Each of these approaches offers different opportunities and problems. All these models are based on a sound physical basis, however none of these have general validity in taking into consideration all detail of the physical chemical interaction. The merits of the models can only be judged by their ability to reproduce physical reality and consequences of operational and geometric conditions in a combustion system. The presentation demonstrates and discusses the development of a coherent combustion technology for energy conversion and safety based on the Eddy Dissipation Concept by Magnussen. (author) 30 refs.

  20. Modeling the chemical evolution of nitrogen oxides near roadways

    Science.gov (United States)

    Wang, Yan Jason; DenBleyker, Allison; McDonald-Buller, Elena; Allen, David; Zhang, K. Max

    2011-01-01

    The chemical evolution of nitrogen dioxide (NO 2) and nitrogen monoxide (NO) in the vicinity of roadways is numerically investigated using a computational fluid dynamics model, CFD-VIT-RIT and a Gaussian-based model, CALINE4. CFD-VIT-RIT couples a standard k- ɛ turbulence model for turbulent mixing and the Finite-Rate model for chemical reactions. CALINE4 employs a discrete parcel method, assuming that chemical reactions are independent of the dilution process. The modeling results are compared to the field measurement data collected near two roadways in Austin, Texas, State Highway 71 (SH-71) and Farm to Market Road 973 (FM-973), under parallel and perpendicular wind conditions during the summer of 2007. In addition to ozone (O 3), other oxidants and reactive species including hydroperoxyl radical (HO 2), organic peroxyl radical (RO 2), formaldehyde (HCHO) and acetaldehyde (CH 3CHO) are considered in the transformation from NO to NO 2. CFD-VIT-RIT is shown to be capable of predicting both NO x and NO 2 profiles downwind. CALINE4 is able to capture the NO x profiles, but underpredicts NO 2 concentrations under high wind velocity. Our study suggests that the initial NO 2/NO x ratios have to be carefully selected based on traffic conditions in order to assess NO 2 concentrations near roadways. The commonly assumed NO 2/NO x ratio by volume of 5% may not be suitable for most roadways, especially those with a high fraction of heavy-duty truck traffic. In addition, high O 3 concentrations and high traffic volumes would lead to the peak NO 2 concentration occurring near roadways with elevated concentrations persistent over a long distance downwind.

  1. Structural Equation Model of Health Promoting Behaviors for Health Information Seekers with Mobile.

    Science.gov (United States)

    Choi, Hanna; Kim, Jeongeun; Byun, Ahjung

    2016-01-01

    This study was conducted on verifying whether variables such as prior health related behaviors, health literacy, interpersonal influence, perceived ease of use and usefulness of health information, and behavioral intention could predict actual health promoting behaviors of consumers using health information with mobile in the future. The research model was based on Technology Acceptance Model. Data were collected from 199 mobile health information seekers. Participants' actual health promoting behaviors were checked after 3 months from pre-data collection. The final modified model had good fit indices.

  2. Strongly Interacting Matter at Finite Chemical Potential: Hybrid Model Approach

    Science.gov (United States)

    Srivastava, P. K.; Singh, C. P.

    2013-06-01

    Search for a proper and realistic equation of state (EOS) for strongly interacting matter used in the study of the QCD phase diagram still appears as a challenging problem. Recently, we constructed a hybrid model description for the quark-gluon plasma (QGP) as well as hadron gas (HG) phases where we used an excluded volume model for HG and a thermodynamically consistent quasiparticle model for the QGP phase. The hybrid model suitably describes the recent lattice results of various thermodynamical as well as transport properties of the QCD matter at zero baryon chemical potential (μB). In this paper, we extend our investigations further in obtaining the properties of QCD matter at finite value of μB and compare our results with the most recent results of lattice QCD calculation.

  3. Unified Ion-chemical Model for the Middle Atmosphere

    Science.gov (United States)

    Kamsali, Nagaraja; Kamsali, Nagaraja; Datta, Jayati; Prasad, Bsn

    The importance of ion-chemical model studies in our understanding of middle atmospheric regions needs no special emphasis. Present day knowledge of middle atmosphere (0-100 km) has come from two distinct experimental developments: first, in situ measurements of ion composition by balloons and sounding rockets and second, laboratory investigations on ionchemical reactions of importance at these heights, determination of reaction rate coefficients and their temperature dependence. Model studies act as an interface between these, to generate theoretical estimates of ion composition and their derivatives (e.g. electrical conductivity) by using as input the laboratory data on reaction rate coefficients and the data on neutral species density, ionization flux, temperature etc. Free electrons exist only in the mesosphere. Positive molecular ions dominate the upper mesospheric heights and heavy positive and negative cluster ions appearing at the lower mesospheric heights continue to dominate in strato and troposphere. The equilibrium density of electrons and ionic species is governed by: a) ionization of the atmospheric constituents producing electron-positive ion pair b)gas-phase ion-chemical reactions that convert the electrons and primary positive ions into heavy cluster ions of both polarity c)heterogeneous ion-chemical reactions for producing aerosol ions and d) loss mechanisms for small ions and aerosol ions through recombination of oppositely charged species. Physical entities that control the ion production and loss processes are not the same and vary vastly both in nature and magnitude in the middle atmosphere X-rays, Lymann-alpha and precipitating electrons are the dominant ionizing agents at the mesospheric heights. Cosmic ray ionization that is not so significant in the mesosphere is the sole ionizing agent at stratosphere and troposphere. At the ground level and up to a few tens of meters above the earth's surface, natural radioactivity induced ionization is

  4. Program Models for Mental Health Treatment of Refugees.

    Science.gov (United States)

    Jaranson, James M.; Bamford, Pauline

    This paper presents the approach used by the Technical Assistance Center (TAC) of the University of Minnesota's Refugee Assistance Program in Mental Health for identifying successful and culturally sensitive mental health service delivery models. It divides these into four categories: the psychiatric model; the community mental health model; the…

  5. Modeling Nonlinear Adsorption with a Single Chemical Parameter: Predicting Chemical Median Langmuir Binding Constants.

    Science.gov (United States)

    Davis, Craig Warren; Di Toro, Dominic M

    2015-07-07

    Procedures for accurately predicting linear partition coefficients onto various sorbents (e.g., organic carbon, soils, clay) are reliable and well established. However, similar procedures for the prediction of sorption parameters of nonlinear isotherm models are not. The purpose of this paper is to present a procedure for predicting nonlinear isotherm parameters, specifically the median Langmuir binding constants, K̃L, obtained utilizing the single-chemical parameter log-normal Langmuir isotherm developed in the accompanying work. A reduced poly parameter linear free energy relationship (pp-LFER) is able to predict median Langmuir binding constants for graphite, charcoal, and Darco granular activated carbon (GAC) adsorption data. For the larger F400 GAC data set, a single pp-LFER model was insufficient, as a plateau is observed for the median Langmuir binding constants of larger molecular volume sorbates. This volumetric cutoff occurs in proximity to the median pore diameter for F400 GAC. A log-linear relationship exists between the aqueous solubility of these large compounds and their median Langmuir binding constants. Using this relationship for the chemicals above the volumetric cutoff and the pp-LFER below the cutoff, the median Langmuir binding constants can be predicted with a root-mean square error for graphite (n = 13), charcoal (n = 11), Darco GAC (n = 14), and F400 GAC (n = 44) of 0.129, 0.307, 0.407, and 0.424, respectively.

  6. Health literacy and public health: A systematic review and integration of definitions and models

    Directory of Open Access Journals (Sweden)

    Sørensen Kristine

    2012-01-01

    Full Text Available Abstract Background Health literacy concerns the knowledge and competences of persons to meet the complex demands of health in modern society. Although its importance is increasingly recognised, there is no consensus about the definition of health literacy or about its conceptual dimensions, which limits the possibilities for measurement and comparison. The aim of the study is to review definitions and models on health literacy to develop an integrated definition and conceptual model capturing the most comprehensive evidence-based dimensions of health literacy. Methods A systematic literature review was performed to identify definitions and conceptual frameworks of health literacy. A content analysis of the definitions and conceptual frameworks was carried out to identify the central dimensions of health literacy and develop an integrated model. Results The review resulted in 17 definitions of health literacy and 12 conceptual models. Based on the content analysis, an integrative conceptual model was developed containing 12 dimensions referring to the knowledge, motivation and competencies of accessing, understanding, appraising and applying health-related information within the healthcare, disease prevention and health promotion setting, respectively. Conclusions Based upon this review, a model is proposed integrating medical and public health views of health literacy. The model can serve as a basis for developing health literacy enhancing interventions and provide a conceptual basis for the development and validation of measurement tools, capturing the different dimensions of health literacy within the healthcare, disease prevention and health promotion settings.

  7. Health literacy and public health: A systematic review and integration of definitions and models

    LENUS (Irish Health Repository)

    Sorensen, Kristine

    2012-01-25

    Abstract Background Health literacy concerns the knowledge and competences of persons to meet the complex demands of health in modern society. Although its importance is increasingly recognised, there is no consensus about the definition of health literacy or about its conceptual dimensions, which limits the possibilities for measurement and comparison. The aim of the study is to review definitions and models on health literacy to develop an integrated definition and conceptual model capturing the most comprehensive evidence-based dimensions of health literacy. Methods A systematic literature review was performed to identify definitions and conceptual frameworks of health literacy. A content analysis of the definitions and conceptual frameworks was carried out to identify the central dimensions of health literacy and develop an integrated model. Results The review resulted in 17 definitions of health literacy and 12 conceptual models. Based on the content analysis, an integrative conceptual model was developed containing 12 dimensions referring to the knowledge, motivation and competencies of accessing, understanding, appraising and applying health-related information within the healthcare, disease prevention and health promotion setting, respectively. Conclusions Based upon this review, a model is proposed integrating medical and public health views of health literacy. The model can serve as a basis for developing health literacy enhancing interventions and provide a conceptual basis for the development and validation of measurement tools, capturing the different dimensions of health literacy within the healthcare, disease prevention and health promotion settings.

  8. Gompertz kinetics model of fast chemical neurotransmission currents.

    Science.gov (United States)

    Easton, Dexter M

    2005-10-01

    At a chemical synapse, transmitter molecules ejected from presynaptic terminal(s) bind reversibly with postsynaptic receptors and trigger an increase in channel conductance to specific ions. This paper describes a simple but accurate predictive model for the time course of the synaptic conductance transient, based on Gompertz kinetics. In the model, two simple exponential decay terms set the rates of development and decline of transmitter action. The first, r, triggering conductance activation, is surrogate for the decelerated rate of growth of conductance, G. The second, r', responsible for Y, deactivation of the conductance, is surrogate for the decelerated rate of decline of transmitter action. Therefore, the differential equation for the net conductance change, g, triggered by the transmitter is dg/dt=g(r-r'). The solution of that equation yields the product of G(t), representing activation, and Y(t), which defines the proportional decline (deactivation) of the current. The model fits, over their full-time course, published records of macroscopic ionic current associated with fast chemical transmission. The Gompertz model is a convenient and accurate method for routine analysis and comparison of records of synaptic current and putative transmitter time course. A Gompertz fit requiring only three independent rate constants plus initial current appears indistinguishable from a Markov fit using seven rate constants.

  9. Chemical kinetic modeling of H{sub 2} applications

    Energy Technology Data Exchange (ETDEWEB)

    Marinov, N.M.; Westbrook, C.K.; Cloutman, L.D. [Lawrence Livermore National Lab., CA (United States)] [and others

    1995-09-01

    Work being carried out at LLNL has concentrated on studies of the role of chemical kinetics in a variety of problems related to hydrogen combustion in practical combustion systems, with an emphasis on vehicle propulsion. Use of hydrogen offers significant advantages over fossil fuels, and computer modeling provides advantages when used in concert with experimental studies. Many numerical {open_quotes}experiments{close_quotes} can be carried out quickly and efficiently, reducing the cost and time of system development, and many new and speculative concepts can be screened to identify those with sufficient promise to pursue experimentally. This project uses chemical kinetic and fluid dynamic computational modeling to examine the combustion characteristics of systems burning hydrogen, either as the only fuel or mixed with natural gas. Oxidation kinetics are combined with pollutant formation kinetics, including formation of oxides of nitrogen but also including air toxics in natural gas combustion. We have refined many of the elementary kinetic reaction steps in the detailed reaction mechanism for hydrogen oxidation. To extend the model to pressures characteristic of internal combustion engines, it was necessary to apply theoretical pressure falloff formalisms for several key steps in the reaction mechanism. We have continued development of simplified reaction mechanisms for hydrogen oxidation, we have implemented those mechanisms into multidimensional computational fluid dynamics models, and we have used models of chemistry and fluid dynamics to address selected application problems. At the present time, we are using computed high pressure flame, and auto-ignition data to further refine the simplified kinetics models that are then to be used in multidimensional fluid mechanics models. Detailed kinetics studies have investigated hydrogen flames and ignition of hydrogen behind shock waves, intended to refine the detailed reactions mechanisms.

  10. Chemical composition and potential health risks of raw Arabian incense (Bakhour

    Directory of Open Access Journals (Sweden)

    Yehya Elsayed

    2016-07-01

    Full Text Available Burning Arabian incense (Bakhour is a common indoor practice in the Middle East and the Arabian Gulf region. However, the chemical composition of this substance has never been studied. Three different Bakhour brands were selected for this study. A complete chemical profile for the raw samples was determined using carbon, hydrogen, and nitrogen elemental analysis, inductively coupled plasma optical emission spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and gas chromatography mass spectrometry techniques. A wide range of elements and compounds were identified, many of which are hazardous to health. Nitrogen was found in all samples which should raise concerns due to the known health implications of amines, nitrogen oxides and nitrites. In addition toxic metals such as cobalt, copper, iron, nickel, lead, and zinc were also determined in all samples. The amounts of these metals are equivalent to those in raw tobacco, where they are known to pose health risks. Three types of solvents (acetone, dichloromethane and toluene were used for the extraction of organic compounds. Carcinogens, toxins and irritants were found along others of different health implications. Isolation of these compounds provides preliminary evidence on the harmful consequences of being exposed to Bakhour.

  11. Gastrointestinal tract modelling in health and disease

    Institute of Scientific and Technical Information of China (English)

    Dong-Hua Liao; Jing-Bo Zhao; Hans Gregersen

    2009-01-01

    The gastrointestinal (GI) tract is the system of organs within multi-cellular animals that takes in food, digests it to extract energy and nutrients, and expels the remaining waste. The various patterns of GI tract function are generated by the integrated behaviour of multiple tissues and cell types. A thorough study of the GI tract requires understanding of the interactions between cells, tissues and gastrointestinal organs in health and disease. This depends on knowledge, not only of numerous cellular ionic current mechanisms and signal transduction pathways, but also of large scale GI tissue structures and the special distribution of the nervous network. A unique way of coping with this explosion in complexity is mathematical and computational modelling; providing a computational framework for the multilevel modelling and simulation of the human gastrointestinal anatomy and physiology. The aim of this review is to describe the current status of biomechanical modelling work of the GI tract in humans and animals, which can be further used to integrate the physiological, anatomical and medical knowledge of the GI system. Such modelling will aid research and ensure that medical professionals benefit, through the provision of relevant and precise information about the patient's condition and GI remodelling in animal disease models. It will also improve the accuracy and efficiency of medical procedures, which could result in reduced cost for diagnosis and treatment.

  12. The applications of machine learning algorithms in the modeling of estrogen-like chemicals.

    Science.gov (United States)

    Liu, Huanxiang; Yao, Xiaojun; Gramatica, Paola

    2009-06-01

    Increasing concern is being shown by the scientific community, government regulators, and the public about endocrine-disrupting chemicals that, in the environment, are adversely affecting human and wildlife health through a variety of mechanisms, mainly estrogen receptor-mediated mechanisms of toxicity. Because of the large number of such chemicals in the environment, there is a great need for an effective means of rapidly assessing endocrine-disrupting activity in the toxicology assessment process. When faced with the challenging task of screening large libraries of molecules for biological activity, the benefits of computational predictive models based on quantitative structure-activity relationships to identify possible estrogens become immediately obvious. Recently, in order to improve the accuracy of prediction, some machine learning techniques were introduced to build more effective predictive models. In this review we will focus our attention on some recent advances in the use of these methods in modeling estrogen-like chemicals. The advantages and disadvantages of the machine learning algorithms used in solving this problem, the importance of the validation and performance assessment of the built models as well as their applicability domains will be discussed.

  13. Model Organisms Fact Sheet: Using Model Organisms to Study Health and Disease

    Science.gov (United States)

    ... Model Organisms to Study Health and Disease Using Model Organisms to Study Health and Disease Tagline (Optional) ... and treating disease in humans. What is a model? The word model has many meanings, but in ...

  14. Toward a New U.S. Chemicals Policy: Rebuilding the Foundation to Advance New Science, Green Chemistry, and Environmental Health

    Science.gov (United States)

    Wilson, Michael P.; Schwarzman, Megan R.

    2009-01-01

    Objective We describe fundamental weaknesses in U.S. chemicals policy, present principles of chemicals policy reform, and articulate interdisciplinary research questions that should be addressed. With global chemical production projected to double over the next 24 years, federal policies that shape the priorities of the U.S. chemical enterprise will be a cornerstone of sustainability. To date, these policies have largely failed to adequately protect public health or the environment or motivate investment in or scientific exploration of cleaner chemical technologies, known collectively as green chemistry. On this trajectory, the United States will face growing health, environmental, and economic problems related to chemical exposures and pollution. Conclusions Existing policies have produced a U.S. chemicals market in which the safety of chemicals for human health and the environment is undervalued relative to chemical function, price, and performance. This market barrier to green chemistry is primarily a consequence of weaknesses in the Toxic Substances Control Act. These weaknesses have produced a chemical data gap, because producers are not required to investigate and disclose sufficient information on chemicals’ hazard traits to government, businesses that use chemicals, or the public; a safety gap, because government lacks the legal tools it needs to efficiently identify, prioritize, and take action to mitigate the potential health and environmental effects of hazardous chemicals; and a technology gap, because industry and government have invested only marginally in green chemistry research, development, and education. Policy reforms that close the three gaps—creating transparency and accountability in the market—are crucial for improving public and environmental health and reducing the barriers to green chemistry. The European Union’s REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulation has opened an opportunity for

  15. A new extension of the polarizable continuum model: Toward a quantum chemical description of chemical reactions at extreme high pressure.

    Science.gov (United States)

    Cammi, Roberto

    2015-11-15

    A quantum chemical method for studying potential energy surfaces of reactive molecular systems at extreme high pressures is presented. The method is an extension of the standard Polarizable Continuum Model that is usually used for Quantum Chemical study of chemical reactions at a standard condition of pressure. The physical basis of the method and the corresponding computational protocol are described in necessary detail, and an application of the method to the dimerization of cyclopentadiene (up to 20 GPa) is reported.

  16. Modelling of structural effects on chemical reactions in turbulent flows

    Energy Technology Data Exchange (ETDEWEB)

    Gammelsaeter, H.R.

    1997-12-31

    Turbulence-chemistry interactions are analysed using algebraic moment closure for the chemical reaction term. The coupling between turbulence and chemical length and time scales generate a complex interaction process. This interaction process is called structural effects in this work. The structural effects are shown to take place on all scales between the largest scale of turbulence and the scales of the molecular motions. The set of equations describing turbulent correlations involved in turbulent reacting flows are derived. Interactions are shown schematically using interaction charts. Algebraic equations for the turbulent correlations in the reaction rate are given using the interaction charts to include the most significant couplings. In the frame of fundamental combustion physics, the structural effects appearing on the small scales of turbulence are proposed modelled using a discrete spectrum of turbulent scales. The well-known problem of averaging the Arrhenius law, the specific reaction rate, is proposed solved using a presumed single variable probability density function and a sub scale model for the reaction volume. Although some uncertainties are expected, the principles are addressed. Fast chemistry modelling is shown to be consistent in the frame of algebraic moment closure when the turbulence-chemistry interaction is accounted for in the turbulent diffusion. The modelling proposed in this thesis is compared with experimental data for an laboratory methane flame and advanced probability density function modelling. The results show promising features. Finally it is shown a comparison with full scale measurements for an industrial burner. All features of the burner are captured with the model. 41 refs., 33 figs.

  17. Meteorological and Chemical Urban Scale Modelling for Shanghai Metropolitan Area

    Science.gov (United States)

    Mahura, Alexander; Nuterman, Roman; Gonzalez-Aparicio, Iratxe; Amstrup, Bjarne; Yang, Xiaohua; Baklanov, Alexander

    2016-04-01

    Urban air pollution is a serious problem in megacities and major industrial agglomerations of China. Therefore, air quality information is important for public. In particular, the Shanghai metropolitan area is well known as megacity having severe air pollution episodes. The Enviro-HIRLAM (Environment - HIgh Resolution Limited Area Model) is applied for on-line integrated meteorology and atmospheric composition forecasting for the Shanghai region of China. The model setup includes the urban Building Effects Parameterization module, describing different types of urban districts with its own morphological and aerodynamical characteristics. The model is running in downscaling chain from regional-to-urban scales for selected periods in summer and winter having both elevated pollution levels as well as unfavorable meteorological conditions. For these periods, the effects of urbanization are analyzed for spatio-temporal variability of atmospheric and chemical/aerosols patterns. The formation and development of meteorological (air and surface temperature, relative humidity, wind speed, cloud cover, boundary layer height) and chemical/aerosol patterns (concentration and deposition) due to influence of the metropolitan area is evaluated. The impact of Shanghai region on regional-to-urban scales as well as relationship between air pollution and meteorology are estimated.

  18. Mathematical models of thermal and chemical transport in geologic media

    Energy Technology Data Exchange (ETDEWEB)

    Lai, C.-H.

    1985-12-01

    Semi-analytical and numerical methods are used to investigate thermal and chemical transport processes in geologic media. The work is divided into two parts: (1) development of semi-analytical models for the analysis of uncoupled isothermal and nonisothermal fluid flow in naturally fractured media, and (2) development of a high resolution numerical code to address coupled nonisothermal chemical transport in geologic media. A semi-analytical model is developed for well test data analysis in naturally fractured reservoirs. A simple approximate analytical solution for pressure buildup and drawdown tests is developed. Methods based on the approximate solution are developed for the evaluation of important reservoir properties. Type curves for nonisothermal fluid flow in naturally fractured media are developed to design injection systems for maximum energy in hydrothermal systems. An accurate finite difference method for the solution of a convection-diffusion type equation is developed. The method is incorporated in a two-dimensional code to investigate free convection in a porous slab and kinetic silica-water reactions in geothermal systems. A multicomponent model considering the variations of pressure, temperature and silica concentration is developed to interpret the evolution of geothermal systems during exploitation.

  19. Chemical kinetics and combustion modelling with CFX 4

    Energy Technology Data Exchange (ETDEWEB)

    Stopford, P. [AEA Technology, Computational Fluid Dynamics Services Harwell, Oxfordshire (United Kingdom)

    1997-12-31

    The presentation describes some recent developments in combustion and kinetics models used in the CFX software of AEA Technology. Three topics are highlighted: the development of coupled solvers in a traditional `SIMPLE`-based CFD code, the use of detailed chemical kinetics mechanism via `look-up` tables and the application of CFD to large-scale multi-burner combustion plant. The aim is identify those physical approximations and numerical methods that are likely to be most useful in the future and those areas where further developments are required. (author) 6 refs.

  20. Analytical model of plasma-chemical etching in planar reactor

    Science.gov (United States)

    Veselov, D. S.; Bakun, A. D.; Voronov, Yu A.; Kireev, V. Yu; Vasileva, O. V.

    2016-09-01

    The paper discusses an analytical model of plasma-chemical etching in planar diode- type reactor. Analytical expressions of etch rate and etch anisotropy were obtained. It is shown that etch anisotropy increases with increasing the ion current and ion energy. At the same time, etch selectivity of processed material decreases as compared with the mask. Etch rate decreases with the distance from the centre axis of the reactor. To decrease the loading effect, it is necessary to reduce the wafer temperature and pressure in the reactor, as well as increase the gas flow rate through the reactor.

  1. Tribo-chemical mechanisms of copper chemical mechanical planarization (CMP) - Fundamental investigations and integrated modeling

    Science.gov (United States)

    Tripathi, Shantanu

    In this work, copper Chemical Mechanical Planarization is identified primarily as a wear enhanced corrosion process (as opposed to the corrosion enhanced wear process assumed in existing modeling work), where intermittent abrasive action enhances the local oxidation rate, and is followed by time-dependant passivation of copper. Based on this mechanism, an integrated tribo-chemical model of material removal at the abrasive scale was developed based on oxidation of copper. This considers abrasive and pad properties, process parameters, and slurry chemistry. Three important components of this model -- the passivation kinetics of copper in CMP slurry chemicals; the mechanical properties of passive films on copper; and the interaction frequency of copper and abrasives -- are introduced. The first two components, in particular the passivation kinetics of copper, are extensively studied experimentally, while the third component is addressed theoretically. The passivation kinetics of copper (i.e. decrease in oxidation currents as passive films form on bare copper) were investigated by potential step chronoamperometry. Low cost microelectrodes were developed (first of its kind for studying copper CMP) to reduce many of the problems of traditional macroelectrodes, such as interference from capacitive charging, IR drops and low diffusion limited current. Electrochemical impedance spectroscopy (EIS) was used on copper microelectrodes in CMP slurry constituents to obtain equivalent circuit elements associated with different electrochemical phenomena (capacitive, kinetics, diffusion etc.) at different polarization potentials. The circuit elements were used to simulate chronoamperometry in a system where copper actively corrodes at anodic potentials; from the simulation and the experimental results, the current decay in this system was attributed entirely to capacitive charging. The circuit elements were also used to explain the chronoamperometry results in passivating and

  2. Modeling drug- and chemical- induced hepatotoxicity with systems biology approaches

    Directory of Open Access Journals (Sweden)

    Sudin eBhattacharya

    2012-12-01

    Full Text Available We provide an overview of computational systems biology approaches as applied to the study of chemical- and drug-induced toxicity. The concept of ‘toxicity pathways’ is described in the context of the 2007 US National Academies of Science report, Toxicity testing in the 21st Century: A Vision and A Strategy. Pathway mapping and modeling based on network biology concepts are a key component of the vision laid out in this report for a more biologically-based analysis of dose-response behavior and the safety of chemicals and drugs. We focus on toxicity of the liver (hepatotoxicity – a complex phenotypic response with contributions from a number of different cell types and biological processes. We describe three case studies of complementary multi-scale computational modeling approaches to understand perturbation of toxicity pathways in the human liver as a result of exposure to environmental contaminants and specific drugs. One approach involves development of a spatial, multicellular virtual tissue model of the liver lobule that combines molecular circuits in individual hepatocytes with cell-cell interactions and blood-mediated transport of toxicants through hepatic sinusoids, to enable quantitative, mechanistic prediction of hepatic dose-response for activation of the AhR toxicity pathway. Simultaneously, methods are being developing to extract quantitative maps of intracellular signaling and transcriptional regulatory networks perturbed by environmental contaminants, using a combination of gene expression and genome-wide protein-DNA interaction data. A predictive physiological model (DILIsymTM to understand drug-induced liver injury (DILI, the most common adverse event leading to termination of clinical development programs and regulatory actions on drugs, is also described. The model initially focuses on reactive metabolite-induced DILI in response to administration of acetaminophen, and spans multiple biological scales.

  3. Two-dimensional numerical and eco-toxicological modeling of chemical spills

    Institute of Scientific and Technical Information of China (English)

    Suiliang HUANG; Yafei JIA; Sam S. Y. WANG

    2009-01-01

    The effects of chemical spills on aquatic nontarget organisms were evaluated in this study. Based on a review of three types of current eco-toxicological models of chemicals, i.e., ACQUATOX model of the US-EPA, Hudson River Model of PCBs, and critical body residual (CBR) model and dynamic energy budget (DEBtox)model, this paper presents an uncoupled numerical ecotoxicological model. The transport and transformation of spilled chemicals were simulated by a chemical transport model (including flow and sediment transport), and the mortalities of an organism caused by the chemicals were simulated by the extended threshold damage model,separately. Due to extreme scarcity of data, this model was applied to two hypothetical cases of chemical spills happening upstream of a lake. Theoretical analysis and simulated results indicated that this model is capable of reasonably predicting the acute effects of chemical spills on aquatic ecosystems or organism killings.

  4. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  5. Integration Strategies for Efficient Multizone Chemical Kinetics Models

    Energy Technology Data Exchange (ETDEWEB)

    McNenly, M J; Havstad, M A; Aceves, S M; Pitz, W J

    2009-10-15

    Three integration strategies are developed and tested for the stiff, ordinary differential equation (ODE) integrators used to solve the fully coupled multizone chemical kinetics model. Two of the strategies tested are found to provide more than an order of magnitude of improvement over the original, basic level of usage for the stiff ODE solver. One of the faster strategies uses a decoupled, or segregated, multizone model to generate an approximate Jacobian. This approach yields a 35-fold reduction in the computational cost for a 20 zone model. Using the same approximate Jacobian as a preconditioner for an iterative Krylov-type linear system solver, the second improved strategy achieves a 75-fold reduction in the computational cost for a 20 zone model. The faster strategies achieve their cost savings with no significant loss of accuracy. The pressure, temperature and major species mass fractions agree with the solution from the original integration approach to within six significant digits; and the radical mass fractions agree with the original solution to within four significant digits. The faster strategies effectively change the cost scaling of the multizone model from cubic to quadratic, with respect to the number of zones. As a consequence of the improved scaling, the 40 zone model offers more than a 250-fold cost savings over the basic calculation.

  6. The Healthy Ageing Model: health behaviour change for older adults.

    Science.gov (United States)

    Potempa, Kathleen M; Butterworth, Susan W; Flaherty-Robb, Marna K; Gaynor, William L

    2010-01-01

    Proposed is a model of primary care for older adults with chronic health conditions that focuses on active engagement in health care. The Healthy Ageing Model is anchored in established theory on motivation and health behaviour change. The model draws on empirical and applied clinical underpinnings in such diverse areas as health promotion and education, treatment of addictions or obesity, management of chronic diseases, goal-setting, and coaching techniques. The conceptual foundation for the Healthy Ageing Model is described first, followed by a brief description of the key characteristics of the model. In conclusion, suggestions are offered for the clinical application and for further developing the model.

  7. Chemical Emergencies

    Science.gov (United States)

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  8. Uncertainty quantification for quantum chemical models of complex reaction networks.

    Science.gov (United States)

    Proppe, Jonny; Husch, Tamara; Simm, Gregor N; Reiher, Markus

    2016-12-22

    For the quantitative understanding of complex chemical reaction mechanisms, it is, in general, necessary to accurately determine the corresponding free energy surface and to solve the resulting continuous-time reaction rate equations for a continuous state space. For a general (complex) reaction network, it is computationally hard to fulfill these two requirements. However, it is possible to approximately address these challenges in a physically consistent way. On the one hand, it may be sufficient to consider approximate free energies if a reliable uncertainty measure can be provided. On the other hand, a highly resolved time evolution may not be necessary to still determine quantitative fluxes in a reaction network if one is interested in specific time scales. In this paper, we present discrete-time kinetic simulations in discrete state space taking free energy uncertainties into account. The method builds upon thermo-chemical data obtained from electronic structure calculations in a condensed-phase model. Our kinetic approach supports the analysis of general reaction networks spanning multiple time scales, which is here demonstrated for the example of the formose reaction. An important application of our approach is the detection of regions in a reaction network which require further investigation, given the uncertainties introduced by both approximate electronic structure methods and kinetic models. Such cases can then be studied in greater detail with more sophisticated first-principles calculations and kinetic simulations.

  9. Modelling the chemical evolution in galaxies with KROME

    CERN Document Server

    Bovino, Stefano; Capelo, Pedro R; Schleicher, Dominik R G; Banerjee, R

    2015-01-01

    In this paper we present and test chemical models for three-dimensional hydrodynamical simulations of galaxy evolution. The microphysics is modelled by employing the public chemistry package KROME and the chemical networks have been tested to work in a wide range of densities and temperatures. We describe a simple H/He network following the formation of H2, and a more sophisticated network which includes metals. Photochemistry, thermal processes, and different prescriptions for the H2 catalysis on dust are presented and tested within a simple one-zone framework. We explore the effect of changing some of the key parameters such as metallicity, radiation and non-equilibrium versus equilibrium metal cooling approximations on the transition between the different gas phases. We find that employing an accurate treatment of the dust-related processes induces a faster HI-H2 transition. In addition, we show when the equilibrium assumption for metal cooling holds, and how a non-equilibrium approach affects the thermal ...

  10. High Temperature Chemical Kinetic Combustion Modeling of Lightly Methylated Alkanes

    Energy Technology Data Exchange (ETDEWEB)

    Sarathy, S M; Westbrook, C K; Pitz, W J; Mehl, M

    2011-03-01

    Conventional petroleum jet and diesel fuels, as well as alternative Fischer-Tropsch (FT) fuels and hydrotreated renewable jet (HRJ) fuels, contain high molecular weight lightly branched alkanes (i.e., methylalkanes) and straight chain alkanes (n-alkanes). Improving the combustion of these fuels in practical applications requires a fundamental understanding of large hydrocarbon combustion chemistry. This research project presents a detailed high temperature chemical kinetic mechanism for n-octane and three lightly branched isomers octane (i.e., 2-methylheptane, 3-methylheptane, and 2,5-dimethylhexane). The model is validated against experimental data from a variety of fundamental combustion devices. This new model is used to show how the location and number of methyl branches affects fuel reactivity including laminar flame speed and species formation.

  11. Reaction Networks For Interstellar Chemical Modelling: Improvements and Challenges

    CERN Document Server

    Wakelam, V; Herbst, E; Troe, J; Geppert, W; Linnartz, H; Oberg, K; Roueff, E; Agundez, M; Pernot, P; Cuppen, H M; Loison, J C; Talbi, D

    2010-01-01

    We survey the current situation regarding chemical modelling of the synthesis of molecules in the interstellar medium. The present state of knowledge concerning the rate coefficients and their uncertainties for the major gas-phase processes -- ion-neutral reactions, neutral-neutral reactions, radiative association, and dissociative recombination -- is reviewed. Emphasis is placed on those reactions that have been identified, by sensitivity analyses, as 'crucial' in determining the predicted abundances of the species observed in the interstellar medium. These sensitivity analyses have been carried out for gas-phase models of three representative, molecule-rich, astronomical sources: the cold dense molecular clouds TMC-1 and L134N, and the expanding circumstellar envelope IRC +10216. Our review has led to the proposal of new values and uncertainties for the rate coefficients of many of the key reactions. The impact of these new data on the predicted abundances in TMC-1 and L134N is reported. Interstellar dust p...

  12. Mass transport measurements and modeling for chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

    Starr, T.L.; Chiang, D.Y.; Fiadzo, O.G.; Hablutzel, N. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Materials Science and Engineering

    1997-12-01

    This project involves experimental and modeling investigation of densification behavior and mass transport in fiber preforms and partially densified composites, and application of these results to chemical vapor infiltration (CVI) process modeling. This supports work on-going at ORNL in process development for fabrication of ceramic matrix composite (CMC) tubes. Tube-shaped composite preforms are fabricated at ORNL with Nextel{trademark} 312 fiber (3M Corporation, St. Paul, MN) by placing and compressing several layers of braided sleeve on a tubular mandrel. In terms of fiber architecture these preforms are significantly different than those made previously with Nicalon{trademark} fiber (Nippon Carbon Corp., Tokyo, Japan) square weave cloth. The authors have made microstructure and permeability measurements on several of these preforms and a few partially densified composites so as to better understand their densification behavior during CVI.

  13. REPRESENTING AEROSOL DYNAMICS AND PROPERTIES IN CHEMICAL TRANSPORT MODELS BY THE METHOD OF MOMENTS.

    Energy Technology Data Exchange (ETDEWEB)

    SCHWARTZ, S.E.; MCGRAW, R.; BENKOVITZ, C.M.; WRIGHT, D.L.

    2001-04-01

    Atmospheric aerosols, suspensions of solid or liquid particles, are an important multi-phase system. Aerosols scatter and absorb shortwave (solar) radiation, affecting climate (Charlson et al., 1992; Schwartz, 1996) and visibility; nucleate cloud droplet formation, modifying the reflectivity of clouds (Twomey et al., 1984; Schwartz and Slingo, 1996) as well as contributing to composition of cloudwater and to wet deposition (Seinfeld and Pandis, 1998); and affect human health through inhalation (NRC, 1998). Existing and prospective air quality regulations impose standards on concentrations of atmospheric aerosols to protect human health and welfare (EPA, 1998). Chemical transport and transformation models representing the loading and geographical distribution of aerosols and precursor gases are needed to permit development of effective and efficient strategies for meeting air quality standards, and for examining aerosol effects on climate retrospectively and prospectively for different emissions scenarios. Important aerosol properties and processes depend on their size distribution: light scattering, cloud nucleating properties, dry deposition, and penetration into airways of lungs. The evolution of the mass loading itself depends on particle size because of the size dependence of growth and removal processes. For these reasons it is increasingly recognized that chemical transport and transformation models must represent not just the mass loading of atmospheric particulate matter but also the aerosol microphysical properties and the evolution of these properties if aerosols are to be accurately represented in these models. If the size distribution of the aerosol is known, a given property can be evaluated as the integral of the appropriate kernel function over the size distribution. This has motivated the approach of determining aerosol size distribution, and of explicitly representing this distribution and its evolution in chemical transport models.

  14. Overview of chemical modeling of nuclear waste glass dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Bourcier, W.L.

    1991-02-01

    Glass dissolution takes place through metal leaching and hydration of the glass surface accompanied by development of alternation layers of varying crystallinity. The reaction which controls the long-term glass dissolution rate appears to be surface layer dissolution. This reaction is reversible because the buildup of dissolved species in solution slows the dissolution rate due to a decreased dissolution affinity. Glass dissolution rates are therefore highly dependent on silica concentrations in solution because silica is the major component of the alteration layer. Chemical modeling of glass dissolution using reaction path computer codes has successfully been applied to short term experimental tests and used to predict long-term repository performance. Current problems and limitations of the models include a poorly defined long-term glass dissolution mechanism, the use of model parameters determined from the same experiments that the model is used to predict, and the lack of sufficient validation of key assumptions in the modeling approach. Work is in progress that addresses these issues. 41 refs., 7 figs., 2 tabs.

  15. Quality of life in chemical warfare survivors with ophthalmologic injuries: the first results form Iran Chemical Warfare Victims Health Assessment Study

    Directory of Open Access Journals (Sweden)

    Soroush Mohammad

    2009-01-01

    Full Text Available Abstract Background Iraq used chemical weapons extensively against the Iranians during the Iran-Iraq war (1980–1988. The aim of this study was to assess the health related quality of life (HRQOL in people who had ophthalmologic complications due to the sulfur mustard gas exposure during the war. Methods The Veterans and Martyrs Affair Foundation (VMAF database indicated that there were 196 patients with severe ophthalmologic complications due to chemical weapons exposure. Of these, those who gave consent (n = 147 entered into the study. Quality of life was measured using the 36-item Short Form Health Survey (SF-36 and scores were compared to those of the general public. In addition logistic regression analysis was performed to indicate variables that contribute to physical and mental health related quality of life. Results The mean age of the patients was 44.8 (SD = 8.7 ranging from 21 to 75 years. About one-third of the cases (n= 50 reported exposure to chemical weapons more than once. The mean exposure duration to sulfur mustard gas was 21.6 years (SD = 1.2. The lowest scores on the SF-36 subscales were found to be: the role physical and the general health. Quality of life in chemical warfare victims who had ophthalmologic problems was significantly lower than the general public (P Conclusion The study findings suggest that chemical warfare victims with ophthalmologic complications suffer from poor health related quality of life. It seems that the need for provision of health and support for this population is urgent. In addition, further research is necessary to measure health related quality of life in victims with different types of disabilities in order to support and enhance quality of life among this population.

  16. Models of cortical malformation--Chemical and physical.

    Science.gov (United States)

    Luhmann, Heiko J

    2016-02-15

    Pharmaco-resistant epilepsies, and also some neuropsychiatric disorders, are often associated with malformations in hippocampal and neocortical structures. The mechanisms leading to these cortical malformations causing an imbalance between the excitatory and inhibitory system are largely unknown. Animal models using chemical or physical manipulations reproduce different human pathologies by interfering with cell generation and neuronal migration. The model of in utero injection of methylazoxymethanol (MAM) acetate mimics periventricular nodular heterotopia. The freeze lesion model reproduces (poly)microgyria, focal heterotopia and schizencephaly. The in utero irradiation model causes microgyria and heterotopia. Intraperitoneal injections of carmustine 1-3-bis-chloroethyl-nitrosurea (BCNU) to pregnant rats produces laminar disorganization, heterotopias and cytomegalic neurons. The ibotenic acid model induces focal cortical malformations, which resemble human microgyria and ulegyria. Cortical dysplasia can be also observed following prenatal exposure to ethanol, cocaine or antiepileptic drugs. All these models of cortical malformations are characterized by a pronounced hyperexcitability, few of them also produce spontaneous epileptic seizures. This dysfunction results from an impairment in GABAergic inhibition and/or an increase in glutamatergic synaptic transmission. The cortical region initiating or contributing to this hyperexcitability may not necessarily correspond to the site of the focal malformation. In some models wide-spread molecular and functional changes can be observed in remote regions of the brain, where they cause pathophysiological activities. This paper gives an overview on different animal models of cortical malformations, which are mostly used in rodents and which mimic the pathology and to some extent the pathophysiology of neuronal migration disorders associated with epilepsy in humans.

  17. Overview of human health and chemical mixtures: problems facing developing countries.

    Science.gov (United States)

    Yáñ ez, Leticia; Ortiz, Deogracias; Calderón, Jaqueline; Batres, Lilia; Carrizales, Leticia; Mejía, Jesús; Martínez, Lourdes; García-Nieto, Edelmira; Díaz-Barriga, Fernando

    2002-01-01

    In developing countries, chemical mixtures within the vicinity of small-scale enterprises, smelters, mines, agricultural areas, toxic waste disposal sites, etc., often present a health hazard to the populations within those vicinities. Therefore, in these countries, there is a need to study the toxicological effects of mixtures of metals, pesticides, and organic compounds. However, the study of mixtures containing substances such as DDT (dichlorodiphenyltrichloroethane, an insecticide banned in developed nations), and mixtures containing contaminants such as fluoride (of concern only in developing countries) merit special attention. Although the studies may have to take into account simultaneous exposures to metals and organic compounds, there is also a need to consider the interaction between chemicals and other specific factors such as nutritional conditions, alcoholism, smoking, infectious diseases, and ethnicity. PMID:12634117

  18. The application of computer modeling to health effect research

    Energy Technology Data Exchange (ETDEWEB)

    Yang, R.S.H. [Colorado State Univ., Ft. Collins, CO (United States)

    1996-12-31

    In the United States, estimates show that more than 30,000 hazardous waste disposal sites exist, not including military installations, U.S. Department of Energy nuclear facilities, and hundreds and thousands of underground fuel storage tanks; these sites undoubtedly have their own respective hazardous waste chemical problems. When so many sites contain hazardous chemicals, how does one study the health effects of the chemicals at these sites? There could be many different answers, but none would be perfect. For an area as complex and difficult as the study of chemical mixtures associated with hazardous waste disposal sites, there are no perfect approaches and protocols. Human exposure to chemicals, be it environmental or occupational, is rarely, if ever, limited to a single chemical. Therefore, it is essential that we consider multiple chemical effects and interactions in our risk assessment process. Systematic toxicity testing of chemical mixtures in the environment or workplace that uses conventional toxicology methodologies is highly impractical because of the immense numbers of mixtures involved. For example, about 600,000 chemicals are being used in our society. Just considering binary chemical mixtures, this means that there could be 600,000 x 599,999/2 = 359,999,400,000 pairs of chemicals. Assuming that only one in a million of these pairs of chemicals acts synergistically or has other toxicologic interactions, there would still be 359,999 binary chemical mixtures possessing toxicologic interactions. Moreover, toxicologic interactions undoubtedly exist among chemical mixtures with three or more component chemicals; the number of possible combinations for these latter mixtures is almost infinite. These are astronomically large numbers with respect to systematic toxicity testing. 22 refs., 5 figs., 1 tab.

  19. OSIRIS, a quest for proof of principle for integrated testing strategies of chemicals for four human health endpoints.

    Science.gov (United States)

    Vermeire, Theo; Aldenberg, Tom; Buist, Harrie; Escher, Sylvia; Mangelsdorf, Inge; Pauné, Eduard; Rorije, Emiel; Kroese, Dinant

    2013-11-01

    Chemical substances policies in Europe are aiming towards chemical safety and at the same time a reduction in animal testing. These goals are alleged to be reachable by mining as many relevant data as possible, evaluate these data with regard to validity, reliability and relevance, and use of these data in so-called Integrated Testing Strategies (ITS). This paper offers an overview of four human health endpoints that were part of the EU-funded OSIRIS project, aiming to develop ITS fit for the EU chemicals legislation REACH. The endpoints considered cover their categorical as well as continuous characteristics: skin sensitisation, repeated dose toxicity, mutagenicity and carcinogenicity. Detailed papers are published elsewhere in this volume. The stepwise ITS approach developed takes advantage of existing information, groups information about similar substances and integrates exposure considerations. The different and possibly contradictory information is weighted and the respective uncertainties taken into account in a weight of evidence (WoE) approach. In case of data gaps, the ITS proposes the most appropriate method to acquire the missing information. Each building block for the ITS, i.e. each in vivo test, in vitro test, (Q)SAR model or human evidence, is evaluated with regard to quality.

  20. Prioritization of chemicals in the aquatic environment based on risk assessment: analytical, modeling and regulatory perspective.

    Science.gov (United States)

    Guillén, D; Ginebreda, A; Farré, M; Darbra, R M; Petrovic, M; Gros, M; Barceló, D

    2012-12-01

    The extensive and intensive use of chemicals in our developed, highly technological society includes more than 100,000 chemical substances. Significant scientific evidence has lead to the recognition that their improper use and release may result in undesirable and harmful side-effects on both the human and ecosystem health. To cope with them, appropriate risk assessment processes and related prioritization schemes have been developed in order to provide the necessary scientific support for regulatory procedures. In the present paper, two of the elements that constitute the core of risk assessment, namely occurrence and hazard effects, have been discussed. Recent advances in analytical chemistry (sample pre-treatment and instrumental equipment, etc.) have allowed for more comprehensive monitoring of environmental pollution reaching limits of detection up to sub ng L(-1). Alternative to analytical measurements, occurrence models can provide risk managers with a very interesting approach for estimating environmental concentrations from real or hypothetical scenarios. The most representative prioritization schemes used for issuing lists of concerning chemicals have also been examined and put in the context of existing environmental policies for protection strategies and regulations. Finally, new challenges in the field of risk-assessment have been outlined, including those posed by new materials (i.e., nanomaterials), transformation products, multi-chemical exposure, or extension of the risk assessment process to the whole ecosystem.

  1. Health care models guiding mental health policy in Kenya 1965 - 1997

    Directory of Open Access Journals (Sweden)

    Jenkins Rachel

    2010-04-01

    Full Text Available Abstract Background Mental health policy is needed to set the strategy and direction for the provision of mental health services in a country. Policy formulation does not occur in a vacuum, however, but is influenced by local and international factors in the health sector and other sectors. Methods This study was carried out in 1997 to examine the evolution of mental health policy in Kenya between 1965 and 1997 in the context of changing international concepts of health and development. Qualitative content analysis of policy documents was combined with interviews of key policy makers. Results The study showed that during the period 1965-1997 the generic health policy in Kenya changed from one based on the Medical Model in the 1960s and 1970s to one based on the Primary Health Care Model in the late 1970s and the 1980s and finally to one based on the Market Model of health care in the 1990s. The mental health policy, on the other hand, evolved from one based on the Medical Model in the 1960s to one based on the Primary Health Care Model in the 1990s, but did not embrace the Market Model of health care. This resulted in a situation in the 1990s where the mental health policy was rooted in a different conceptual model from that of the generic health policy under which it was supposed to be implemented. This "Model Muddlement" may have impeded the implementation of the mental health policy in Kenya. Conclusions Integration of the national mental health policy with the general health policy and other sector policies would be appropriate and is now underway.

  2. Modelling and implementing electronic health records in Denmark

    DEFF Research Database (Denmark)

    Bernstein, Knut; Rasmussen, Morten Bruun; Vingtoft, Søren;

    2003-01-01

    The Danish Health IT strategy points out that integration between electronic health records (EHR) systems has a high priority. This paper reporst reports new tendencies in modelling and integration platforms globally and how this is reflected in the natinal development.......The Danish Health IT strategy points out that integration between electronic health records (EHR) systems has a high priority. This paper reporst reports new tendencies in modelling and integration platforms globally and how this is reflected in the natinal development....

  3. A Critique of Grossman's Canonical Model of Health Capital.

    Science.gov (United States)

    Sepehri, Ardeshir

    2015-01-01

    In the health economics literature, the demand for health and market health inputs is dominated by adaptations of Grossman's health capital model. The model has been widely used to explore a wide range of issues related to health, socioeconomic inequalities in health, demand for medical care, health preventions, occupational choice, and retirement decisions. The commodity of health is viewed as a durable capital stock that yields a flow of healthy time or illness-free time, that depreciates with age, and that can be augmented with the help of market health inputs and own time. The purpose of this article is to provide a comprehensive critical review of the model. Underlying Grossman's model are a faulty conceptual framework and assumptions that tend to exaggerate the degree of control consumers/patients may have over their state of health and survival. The assumption of full information about one's state of health and the efficacy of various health inputs abstracts away from the problems posed by the agency relationship under uncertainty and informational asymmetry. Grossman's individualistic and mechanistic view of health strips health capital and its production of much of their biological/physiological content and their interactions with the individual's social and physical environment.

  4. How Subchronic and Chronic Health Effects can be Neglected for GMOs, Pesticides or Chemicals

    Directory of Open Access Journals (Sweden)

    Gilles-Eric Séralini, Joël Spiroux de Vendômois, Dominique Cellier, Charles Sultan, Marcello Buiatti, Lou Gallagher, Michael Antoniou, Krishna R. Dronamraju

    2009-01-01

    Full Text Available Chronic health effects are increasing in the world such as cancers, hormonal, reproductive, nervous, or immune diseases, even in young people. During regulatory toxicological subchronic tests to prevent these on mammalian health, prior commercialization of chemicals, including pesticides and drugs, or GMOs, some statistically significant findings may be revealed. This discussion is about the need to investigate the relevant criteria to consider those as biologically significant. The sex differences and the non linear dose or time related effects should be considered in contrast to the claims of a Monsanto-supported expert panel about a GMO, the MON 863 Bt maize, but also for pesticides or drugs, in particular to reveal hormone-dependent diseases and first signs of toxicities.

  5. [HEALTH STATUS OF ELECTROTECHNICAL PERSONNEL EXPOSED TO THE COMBINED IMPACT OF ELECTROMAGNETIC FIELDS OF 50 HZ AND CHEMICALS].

    Science.gov (United States)

    Rusin, M N; Amirov, N Kh; Sibgatullin, A S; Krasnoshchekova, V N

    2015-01-01

    There was performed an analysis of the working conditions and health status of workers of the chemical enterprise. In male electrical staff exposed to electromagnetic fields (EMF) of 50 Hz and chemicals, according to data of periodic medical examinations there was revealed statistically higher incidence of cardiovascular diseases and autonomic disorders. The obtained preliminary results allow to suggest the upsurge of the involvement of the autonomic nervous system in response to the combined effects of EMF of 50 Hz and chemicals.

  6. A microscopic model for chemically-powered Janus motors.

    Science.gov (United States)

    Huang, Mu-Jie; Schofield, Jeremy; Kapral, Raymond

    2016-07-07

    Very small synthetic motors that make use of chemical reactions to propel themselves in solution hold promise for new applications in the development of new materials, science and medicine. The prospect of such potential applications, along with the fact that systems with many motors or active elements display interesting cooperative phenomena of fundamental interest, has made the study of synthetic motors an active research area. Janus motors, comprising catalytic and noncatalytic hemispheres, figure prominently in experimental and theoretical studies of these systems. While continuum models of Janus motor systems are often used to describe motor dynamics, microscopic models that are able to account for intermolecular interactions, many-body concentration gradients, fluid flows and thermal fluctuations provide a way to explore the dynamical behavior of these complex out-of-equilibrium systems that does not rely on approximations that are often made in continuum theories. The analysis of microscopic models from first principles provides a foundation from which the range of validity and limitations of approximate theories of the dynamics may be assessed. In this paper, a microscopic model for the diffusiophoretic propulsion of Janus motors, where motor interactions with the environment occur only through hard collisions, is constructed, analyzed and compared to theoretical predictions. Microscopic simulations of both single-motor and many-motor systems are carried out to illustrate the results.

  7. Guidance on health effects of toxic chemicals. Safety Analysis Report Update Program

    Energy Technology Data Exchange (ETDEWEB)

    Foust, C.B.; Griffin, G.D.; Munro, N.B.; Socolof, M.L.

    1994-02-01

    Martin Marietta Energy Systems, Inc. (MMES), and Martin Marietta Utility Services, Inc. (MMUS), are engaged in phased programs to update the safety documentation for the existing US Department of Energy (DOE)-owned facilities. The safety analysis of potential toxic hazards requires a methodology for evaluating human health effects of predicted toxic exposures. This report provides a consistent set of health effects and documents toxicity estimates corresponding to these health effects for some of the more important chemicals found within MMES and MMUS. The estimates are based on published toxicity information and apply to acute exposures for an ``average`` individual. The health effects (toxicological endpoints) used in this report are (1) the detection threshold; (2) the no-observed adverse effect level; (3) the onset of irritation/reversible effects; (4) the onset of irreversible effects; and (5) a lethal exposure, defined to be the 50% lethal level. An irreversible effect is defined as a significant effect on a person`s quality of life, e.g., serious injury. Predicted consequences are evaluated on the basis of concentration and exposure time.

  8. Reduced Models in Chemical Kinetics via Nonlinear Data-Mining

    Directory of Open Access Journals (Sweden)

    Eliodoro Chiavazzo

    2014-01-01

    Full Text Available The adoption of detailed mechanisms for chemical kinetics often poses two types of severe challenges: First, the number of degrees of freedom is large; and second, the dynamics is characterized by widely disparate time scales. As a result, reactive flow solvers with detailed chemistry often become intractable even for large clusters of CPUs, especially when dealing with direct numerical simulation (DNS of turbulent combustion problems. This has motivated the development of several techniques for reducing the complexity of such kinetics models, where, eventually, only a few variables are considered in the development of the simplified model. Unfortunately, no generally applicable a priori recipe for selecting suitable parameterizations of the reduced model is available, and the choice of slow variables often relies upon intuition and experience. We present an automated approach to this task, consisting of three main steps. First, the low dimensional manifold of slow motions is (approximately sampled by brief simulations of the detailed model, starting from a rich enough ensemble of admissible initial conditions. Second, a global parametrization of the manifold is obtained through the Diffusion Map (DMAP approach, which has recently emerged as a powerful tool in data analysis/machine learning. Finally, a simplified model is constructed and solved on the fly in terms of the above reduced (slow variables. Clearly, closing this latter model requires nontrivial interpolation calculations, enabling restriction (mapping from the full ambient space to the reduced one and lifting (mapping from the reduced space to the ambient one. This is a key step in our approach, and a variety of interpolation schemes are reported and compared. The scope of the proposed procedure is presented and discussed by means of an illustrative combustion example.

  9. Upper D region chemical kinetic modeling of LORE relaxation times

    Science.gov (United States)

    Gordillo-Vázquez, F. J.; Luque, A.; Haldoupis, C.

    2016-04-01

    The recovery times of upper D region electron density elevations, caused by lightning-induced electromagnetic pulses (EMP), are modeled. The work was motivated from the need to understand a recently identified narrowband VLF perturbation named LOREs, an acronym for LOng Recovery Early VLF events. LOREs associate with long-living electron density perturbations in the upper D region ionosphere; they are generated by strong EMP radiated from large peak current intensities of ±CG (cloud to ground) lightning discharges, known also to be capable of producing elves. Relaxation model scenarios are considered first for a weak enhancement in electron density and then for a much stronger one caused by an intense lightning EMP acting as an impulsive ionization source. The full nonequilibrium kinetic modeling of the perturbed mesosphere in the 76 to 92 km range during LORE-occurring conditions predicts that the electron density relaxation time is controlled by electron attachment at lower altitudes, whereas above 79 km attachment is balanced totally by associative electron detachment so that electron loss at these higher altitudes is controlled mainly by electron recombination with hydrated positive clusters H+(H2O)n and secondarily by dissociative recombination with NO+ ions, a process which gradually dominates at altitudes >88 km. The calculated recovery times agree fairly well with LORE observations. In addition, a simplified (quasi-analytic) model build for the key charged species and chemical reactions is applied, which arrives at similar results with those of the full kinetic model. Finally, the modeled recovery estimates for lower altitudes, that is <79 km, are in good agreement with the observed short recovery times of typical early VLF events, which are known to be associated with sprites.

  10. Towards a Unified Theory of Health-Disease: I. Health as a complex model-object

    Directory of Open Access Journals (Sweden)

    Naomar Almeida-Filho

    2013-06-01

    Full Text Available Theory building is one of the most crucial challenges faced by basic, clinical and population research, which form the scientific foundations of health practices in contemporary societies. The objective of the study is to propose a Unified Theory of Health-Disease as a conceptual tool for modeling health-disease-care in the light of complexity approaches. With this aim, the epistemological basis of theoretical work in the health field and concepts related to complexity theory as concerned to health problems are discussed. Secondly, the concepts of model-object, multi-planes of occurrence, modes of health and disease-illness-sickness complex are introduced and integrated into a unified theoretical framework. Finally, in the light of recent epistemological developments, the concept of Health-Disease-Care Integrals is updated as a complex reference object fit for modeling health-related processes and phenomena.

  11. Towards a unified theory of health-disease: I. Health as a complex model-object.

    Science.gov (United States)

    Almeida-Filho, Naomar

    2013-06-01

    Theory building is one of the most crucial challenges faced by basic, clinical and population research, which form the scientific foundations of health practices in contemporary societies. The objective of the study is to propose a Unified Theory of Health-Disease as a conceptual tool for modeling health-disease-care in the light of complexity approaches. With this aim, the epistemological basis of theoretical work in the health field and concepts related to complexity theory as concerned to health problems are discussed. Secondly, the concepts of model-object, multi-planes of occurrence, modes of health and disease-illness-sickness complex are introduced and integrated into a unified theoretical framework. Finally, in the light of recent epistemological developments, the concept of Health-Disease-Care Integrals is updated as a complex reference object fit for modeling health-related processes and phenomena.

  12. Towards an improved modeling of chemical weathering in the SoilGen soil evolution model

    Science.gov (United States)

    Opolot, Emmanuel; Finke, Peter

    2014-05-01

    As the need for soil information particularly in the fields of agriculture, land evaluation, hydrology, biogeochemistry and climate change keeps increasing, models for soil evolution are increasingly becoming valuable tools to provide such soil information. Although still limited, such models are progressively being developed. The SoilGen model is one of such models with capabilities to provide soil information such as soil texture, pH, base saturation, organic carbon, CEC, etc over multi-millennia time scale. SoilGen is a mechanistic water flow driven pedogenetic model describing soil forming processes such as carbon cycling, clay migration, decalcification, bioturbation, physical weathering and chemical weathering. The model has been calibrated and confronted with field measurements in a number of case studies, giving plausible results. Discrepancies between measured and simulated soil properties as concluded from case studies have been mainly attributed to (i) the simple chemical weathering system (ii) poor estimates of initial data inputs such as bulk density and element fluxes, and (iii) incorrect values of variables that describe boundary conditions such as precipitation and potential evapotranspiration. This study focuses on extending the chemical weathering system, such that it can deal with a more heterogeneous composition of primary minerals and includes more elements such as Fe and Si. We propose and discuss here an extended description of chemical weathering in the model that is based on more primary minerals, taking into account the role of the specific area of these minerals, and the effect of physical weathering on these specific areas over time. In the initial stage, the proposed chemical weathering mechanism is also implemented in PHREEQC (a widely applied geochemical code with capabilities to simulate equilibrium reactions involving water and minerals, surface complexes and ion exchangers, etc.) to facilitate comparison with the model results

  13. The Development of a Secondary School Health Assessment Model

    Science.gov (United States)

    Sriring, Srinual; Erawan, Prawit; Sriwarom, Monoon

    2015-01-01

    The objective of this research was to: 1) involved a survey of information relating to secondary school health, 2) involved the construction of a model of health assessment and a handbook for using the model in secondary school, 3) develop an assessment model for secondary school. The research included 3 phases. (1) involved a survey of…

  14. Modeling Chemical Mechanical Polishing with Couple Stress Fluids

    Institute of Scientific and Technical Information of China (English)

    张朝辉; 雒建斌; 温诗铸

    2004-01-01

    Chemical mechanical polishing (CMP) is a manufacturing process used to achieve high levels of global and local planarity.Currently, the slurries used in CMP usually contain nanoscale particles to accelerate the removal ratio and to optimize the planarity, whose rheological properties can no longer be accurately modeled with Newtonian fluids.The Reynolds equation, including the couple stress effects, was derived in this paper.The equation describes the mechanism to solve the CMP lubrication equation with the couple stress effects.The effects on load and moments resulting from the various parameters, such as pivot height, roll angle, and pitch angle, were subsequently simulated.The results show that the couple stress can provide higher load and angular moments.This study sheds some lights into the mechanism of the CMP process.

  15. VARIOUS PHARMACEUTICALS INCLUDING DRUGS AND INDUSTRIAL CHEMICALS AS ENVIRONMENTAL HEALTH HAZARDS

    Directory of Open Access Journals (Sweden)

    Anita Kirrolia and Vikas Nehra*

    2012-11-01

    Full Text Available This review describes the potential and, in particular, some relevant hazards associated with the use of veterinary drugs, various pharmaceuticals and industrial chemicals that have produced serious environmental risks and affected the life of people along with other animals by posing great health risks. Risk analysis regarding these problems has also been discussed with the measures to handle the problem at global level. The most contentious residues which occur in meat, milk and eggs along with the environment are antibacterial drugs, hormonal growth promoters, heavy metals and industrial chemicals that are producing potential toxic health effects that include systemic toxicity, mutations, cancer, birth defects and reproductive disorders. Systemic toxicity involves changes in the structure and function of organs and organ systems: weight change, structural alterations and changes in organ system or whole animal function. Functional effects may include changes in the lungs, liver, kidneys, cardiovascular function, brain, nervous system activity, behavior and in production of resistance to disease. Furthermore, continued monitoring and periodic reassessment of risks posed by these contaminants is needed to detect or anticipate new problems so that appropriate action can be taken in the interests of public safety.

  16. Evidence of Coal-Fly-Ash Toxic Chemical Geoengineering in the Troposphere: Consequences for Public Health.

    Science.gov (United States)

    Herndon, J Marvin

    2015-08-11

    The widespread, intentional and increasingly frequent chemical emplacement in the troposphere has gone unidentified and unremarked in the scientific literature for years. The author presents evidence that toxic coal combustion fly ash is the most likely aerosolized particulate sprayed by tanker-jets for geoengineering, weather-modification and climate-modification purposes and describes some of the multifold consequences on public health. Two methods are employed: (1) Comparison of 8 elements analyzed in rainwater, leached from aerosolized particulates, with corresponding elements leached into water from coal fly ash in published laboratory experiments, and (2) Comparison of 14 elements analyzed in dust collected outdoors on a high-efficiency particulate air (HEPA) filter with corresponding elements analyzed in un-leached coal fly ash material. The results show: (1) the assemblage of elements in rainwater and in the corresponding experimental leachate are essentially identical. At a 99% confidence interval, they have identical means (T-test) and identical variances (F-test); and (2) the assemblage of elements in the HEPA dust and in the corresponding average un-leached coal fly ash are likewise essentially identical. The consequences on public health are profound, including exposure to a variety of toxic heavy metals, radioactive elements, and neurologically-implicated chemically mobile aluminum released by body moisture in situ after inhalation or through transdermal induction.

  17. Evidence of Coal-Fly-Ash Toxic Chemical Geoengineering in the Troposphere: Consequences for Public Health

    Directory of Open Access Journals (Sweden)

    J. Marvin Herndon

    2015-08-01

    Full Text Available The widespread, intentional and increasingly frequent chemical emplacement in the troposphere has gone unidentified and unremarked in the scientific literature for years. The author presents evidence that toxic coal combustion fly ash is the most likely aerosolized particulate sprayed by tanker-jets for geoengineering, weather-modification and climate-modification purposes and describes some of the multifold consequences on public health. Two methods are employed: (1 Comparison of 8 elements analyzed in rainwater, leached from aerosolized particulates, with corresponding elements leached into water from coal fly ash in published laboratory experiments, and (2 Comparison of 14 elements analyzed in dust collected outdoors on a high-efficiency particulate air (HEPA filter with corresponding elements analyzed in un-leached coal fly ash material. The results show: (1 the assemblage of elements in rainwater and in the corresponding experimental leachate are essentially identical. At a 99% confidence interval, they have identical means (T-test and identical variances (F-test; and (2 the assemblage of elements in the HEPA dust and in the corresponding average un-leached coal fly ash are likewise essentially identical. The consequences on public health are profound, including exposure to a variety of toxic heavy metals, radioactive elements, and neurologically-implicated chemically mobile aluminum released by body moisture in situ after inhalation or through transdermal induction.

  18. Material removal model for non-contact chemical mechanical polishing

    Institute of Scientific and Technical Information of China (English)

    ZHANG JianQun; ZHANG ChaoHui

    2008-01-01

    Material removal mechanism under non-contact condition between the pad and the wafer in the chemical mechanical polishing (CMP) process is investigated. Based on the assumption that almost all effective material removals take place due to the active abrasives which cut material through the plowing effects. A novel model is developed to predict the material removal rate (MRR) under non-contact condition between the pad and the wafer in CMP. Validated by the experimental data, the model is proved to be able to predict the change of MRR under non-contact condition. Numerical simulation of the model shows: the relative velocity u between the pad and the wafer and fluid viscosity η are the most important factors which impact MRR under non-contact condition; load changes of wafer also affects the MRR, but the effect is not as obvious as the relative velocity and fluid viscosity;when the radius of abrasive is not less than 50nm, the impact of MRR alone with the changes in the size of the abrasive can be ignored.

  19. Modelling stratospheric chemistry in a global three-dimensional chemical transport model

    Energy Technology Data Exchange (ETDEWEB)

    Rummukainen, M. [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

    1995-12-31

    Numerical modelling of atmospheric chemistry aims to increase the understanding of the characteristics, the behavior and the evolution of atmospheric composition. These topics are of utmost importance in the study of climate change. The multitude of gases and particulates making up the atmosphere and the complicated interactions between them affect radiation transfer, atmospheric dynamics, and the impacts of anthropogenic and natural emissions. Chemical processes are fundamental factors in global warming, ozone depletion and atmospheric pollution problems in general. Much of the prevailing work on modelling stratospheric chemistry has so far been done with 1- and 2-dimensional models. Carrying an extensive chemistry parameterisation in a model with high spatial and temporal resolution is computationally heavy. Today, computers are becoming powerful enough to allow going over to 3-dimensional models. In order to concentrate on the chemistry, many Chemical Transport Models (CTM) are still run off-line, i.e. with precalculated and archived meteorology and radiation. In chemistry simulations, the archived values drive the model forward in time, without interacting with the chemical evolution. This is an approach that has been adopted in stratospheric chemistry modelling studies at the Finnish Meteorological Institute. In collaboration with the University of Oslo, a development project was initiated in 1993 to prepare a stratospheric chemistry parameterisation, fit for global 3-dimensional modelling. This article presents the parameterisation approach. Selected results are shown from basic photochemical simulations

  20. Chemical Reaction and Flow Modeling in Fullerene and Nanotube Production

    Science.gov (United States)

    Scott, Carl D.; Farhat, Samir; Greendyke, Robert B.

    2004-01-01

    The development of processes to produce fullerenes and carbon nanotubes has largely been empirical. Fullerenes were first discovered in the soot produced by laser ablation of graphite [1]and then in the soot of electric arc evaporated carbon. Techniques and conditions for producing larger and larger quantities of fullerenes depended mainly on trial and error empirical variations of these processes, with attempts to scale them up by using larger electrodes and targets and higher power. Various concepts of how fullerenes and carbon nanotubes were formed were put forth, but very little was done based on chemical kinetics of the reactions. This was mainly due to the complex mixture of species and complex nature of conditions in the reactors. Temperatures in the reactors varied from several thousand degrees Kelvin down to near room temperature. There are hundreds of species possible, ranging from atomic carbon to large clusters of carbonaceous soot, and metallic catalyst atoms to metal clusters, to complexes of metals and carbon. Most of the chemical kinetics of the reactions and the thermodynamic properties of clusters and complexes have only been approximated. In addition, flow conditions in the reactors are transient or unsteady, and three dimensional, with steep spatial gradients of temperature and species concentrations. All these factors make computational simulations of reactors very complex and challenging. This article addresses the development of the chemical reaction involved in fullerene production and extends this to production of carbon nanotubes by the laser ablation/oven process and by the electric arc evaporation process. In addition, the high-pressure carbon monoxide (HiPco) process is discussed. The article is in several parts. The first one addresses the thermochemical aspects of modeling; and considers the development of chemical rate equations, estimates of reaction rates, and thermodynamic properties where they are available. The second part

  1. Modeling and optimization of a sequence of chemical cleaning cycles in dead-end ultrafiltration

    NARCIS (Netherlands)

    Zondervan, Edwin; Betlem, Ben H.L.; Blankert, Bastiaan; Roffel, Brian

    2008-01-01

    In this paper a chemical cleaning sequence model is proposed that can be used to predict the fouling status of a membrane during multiple chemical cleaning cycles. The proposed model is used to minimize the overall operating costs – based on chemicals consumption, energy consumption and investment c

  2. Iceland as a Model for Chemical Alteration on Mars

    Science.gov (United States)

    Bishop, J. L.; Schiffman, P.; Murad, E.; Southard, R.

    2001-03-01

    Subglacial volcanic activity on Iceland has led to the formation of a variety of silicate and iron oxide-rich alteration products that may ressemble chemical alteration on Mars. The spectral and chemical properties of Icelandic samples are presented.

  3. Access and use of information resources in assessing health risks from chemical exposure: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-31

    Health risk assessment is based on access to comprehensive information about potentially hazardous agents in question. Relevant information is scattered throughout the literature, and often is not readily accessible. To be useful in assessment efforts, emerging scientific findings, risk assess parameters, and associated data must be compiled and evaluated systemically. The US Environmental Protection Agency (EPA) and Oak Ridge National Laboratory (ORNL) are among the federal agencies heavily involved in this effort. This symposium was a direct response by EPA and ORNL to the expressed needs of individuals involved in assessing risks from chemical exposure. In an effort to examine the state of the risk assessment process, the availability of toxicological information, and the future development and transfer of this information, the symposium provided an excellent cadre of speakers and participants from state and federal agencies, academia and research laboratories to address these topics. This stimulating and productive gathering discussed concerns associated with (1) environmental contamination by chemicals; (2) laws regulating chemicals; (3) information needs and resources; (4) applications; (5) challenges and priorities; and (6)future issues. Individual reports are processed separately for the data bases.

  4. Occupational risks for health of the workers of the chemical complex

    Directory of Open Access Journals (Sweden)

    E.T. Valeyeva

    2016-09-01

    Full Text Available The article summarizes the materials of long-term studies to assess the working conditions, state of health in workers of the chemical industry - mainly manufacturers of ethylbenzene, styrene, olefin oxides, rocket fuel. It was found that the most adverse working conditions are typical for the production of heptyl, rubber and fiberglass. The causal relationships of working conditions in the form of an increased incidence of early (pre-clinical stages of occupational diseases, as well as major chronic non-communicable diseases, are identified. It is shown that depending on the tropism, mechanism of action and intensity of the chemical factor a clear staging of the development of pathological changes in the body is recorded. A very high degree of professional conditionality of early toxic hepatitis stages (biliary dyskinesia in a heptyl production operator was determined, as well as initial manifestations of autonomic-sensory polyneuropathy in hands of the workers splicing rubber products, specific changes of the hand skin in glass production operators. Production-related diseases with a high degree of conditionality in certain categories of workers include diseases of the musculoskeletal system; hypertension had an average degree of conditionality. During in-depth medical examination of 2411 workers it was found that the largest number of healthy individuals were identified in the bulk manufacture of ethylbenzene – styrene (54.7 %, and olefin oxide (35,0 % of the number of inspected workers, the least number (12 % – in the manufacture of rubber products. The remaining workers demonstrated the pathology of various organs and systems. Based on the results of risk assessment and professional damage to the workers’ health the chemical productions are ranked according to their degree of danger, a system of preventive measures and risk management principles has been developed. The programme implementation resulted in the positive effect of more

  5. Review of existing terrestrial bioaccumulation models and terrestrial bioaccumulation modeling needs for organic chemicals.

    Science.gov (United States)

    Gobas, Frank A P C; Burkhard, Lawrence P; Doucette, William J; Sappington, Keith G; Verbruggen, Eric M J; Hope, Bruce K; Bonnell, Mark A; Arnot, Jon A; Tarazona, Jose V

    2016-01-01

    Protocols for terrestrial bioaccumulation assessments are far less-developed than for aquatic systems. This article reviews modeling approaches that can be used to assess the terrestrial bioaccumulation potential of commercial organic chemicals. Models exist for plant, invertebrate, mammal, and avian species and for entire terrestrial food webs, including some that consider spatial factors. Limitations and gaps in terrestrial bioaccumulation modeling include the lack of QSARs for biotransformation and dietary assimilation efficiencies for terrestrial species; the lack of models and QSARs for important terrestrial species such as insects, amphibians and reptiles; the lack of standardized testing protocols for plants with limited development of plant models; and the limited chemical domain of existing bioaccumulation models and QSARs (e.g., primarily applicable to nonionic organic chemicals). There is an urgent need for high-quality field data sets for validating models and assessing their performance. There is a need to improve coordination among laboratory, field, and modeling efforts on bioaccumulative substances in order to improve the state of the science for challenging substances.

  6. The Humanistic Approach: A Model For Dental Health Curriculums.

    Science.gov (United States)

    Beall, Sue; Hurley, Robert S.

    1982-01-01

    A special dental health curriculum, called the Tattletooth Curriculum, demonstrates the use of the humanistic model in health education and its concern for the learner as a total person. The main concept in the development of this curriculum is that the prospect for changing behavior is unlikely unless the health information is personally…

  7. [Citizen constitution and social representations: reflecting about health care models].

    Science.gov (United States)

    da Silva, Sílvio Eder Dias; Ramos, Flávia Regina Souza; Martins, Cleusa Rios; Padilha, Maria Itayra; Vasconcelos, Esleane Vilela

    2010-12-01

    This article presents a reflection on the meaning of the terms citizenship and health, addressing the Theory of Social Representations as a strategy for implementing and evaluating health care models in Brazil. First, a brief history about the concept of citizenship is presented; then the article addresses the principles of freedom and equality according to Kant; the third section of the article shows that health is as a right of the citizen and a duty of the state. Finally, the Theory of Social Representations is emphasized as a strategy to evaluate and implement the health services provided to citizens by the current health care models in Brazil.

  8. Designing a health equity audit model for Iran in 2010

    Directory of Open Access Journals (Sweden)

    Saeed Karimi

    2011-01-01

    Full Text Available Background: Health equity audit, as an alternative solution, is a process by which local partners systematically review inequalities in the patients` health, their access to appropriate services and health system outputs. Then, necessary activities needed in order to have more equitable services are agreed on and these concurrences become the executive scheme and action initiates. Therefore, it is pivotal for health care organizations to pay special attention to this important topic. The objective of the current study was to review the health equity audit model in different countries to gather viewpoints of various involved groups in health sector, particularly health experts, and to offer a practical and appropriate model for health equity audit in Iran. Methods: This study adopted applied research approach in two phases. In the first step, this study conducted theoretical health equity audit models in the texts; the experiences of other countries were studied and the most appropriate model for Iranian health system was selected. In the second step, this study employed the Delphi technique. According to the Delphi technique the questionnaire applied in order to gather data and then, the final model was extracted. Results: Agreeable topics, performing agencies, 6 equity audit stages, and equity indicators under 3 main parts with 16 sub-sections were elaborated and viewpoints of Iranian experts in the above fields were gathered and presented as the proposed health equity audit model for Iran. Conclusions: This study reviewed the model of health equity audit for UK and provided a comparative model for health system of Iran with respect to the opinions of academic experts.

  9. Implementation of a vibrationally linked chemical reaction model for DSMC

    Science.gov (United States)

    Carlson, A. B.; Bird, Graeme A.

    1994-01-01

    A new procedure closely linking dissociation and exchange reactions in air to the vibrational levels of the diatomic molecules has been implemented in both one- and two-dimensional versions of Direct Simulation Monte Carlo (DSMC) programs. The previous modeling of chemical reactions with DSMC was based on the continuum reaction rates for the various possible reactions. The new method is more closely related to the actual physics of dissociation and is more appropriate to the particle nature of DSMC. Two cases are presented: the relaxation to equilibrium of undissociated air initially at 10,000 K, and the axisymmetric calculation of shuttle forebody heating during reentry at 92.35 km and 7500 m/s. Although reaction rates are not used in determining the dissociations or exchange reactions, the new method produces rates which agree astonishingly well with the published rates derived from experiment. The results for gas properties and surface properties also agree well with the results produced by earlier DSMC models, equilibrium air calculations, and experiment.

  10. A Chemical Evolution Model for the Fornax Dwarf Spheroidal Galaxy

    CERN Document Server

    Yuan, Zhen; Jing, Y P

    2015-01-01

    Fornax is the brightest Milky Way (MW) dwarf spheroidal galaxy and its star formation history (SFH) has been derived from observations. We estimate the time evolution of its gas mass and net inflow and outflow rates from the SFH using a simple star formation law that relates the star formation rate to the gas mass. We present a chemical evolution model on a 2D mass grid with supernovae (SNe) as sources of metal enrichment. We find that a key parameter controlling the enrichment is the mass M_x of the gas to mix with the ejecta from each SN. The choice of M_x depends on the evolution of SN remnants and on the global gas dynamics. It differs between the two types of SNe involved and between the periods before and after Fornax became an MW satellite at time t = t_sat . Our results indicate that due to the global gas outflow at t > t_sat , part of the ejecta from each SN may directly escape from Fornax. Sample results from our model are presented and compared with data.

  11. On The Stability Of Model Flows For Chemical Vapour Deposition

    Science.gov (United States)

    Miller, Robert

    2016-11-01

    The flow in a chemical vapour deposition (CVD) reactor is assessed. The reactor is modelled as a flow over an infinite-radius rotating disk, where the mean flow and convective instability of the disk boundary layer are measured. Temperature-dependent viscosity and enforced axial flow are used to model the steep temperature gradients present in CVD reactors and the pumping of the gas towards the disk, respectively. Increasing the temperature-dependence parameter of the fluid viscosity (ɛ) results in an overall narrowing of the fluid boundary layer. Increasing the axial flow strength parameter (Ts) accelerates the fluid both radially and axially, while also narrowing the thermal boundary layer. It is seen that when both effects are imposed, the effects of axial flow generally dominate those of the viscosity temperature dependence. A local stability analysis is performed and the linearized stability equations are solved using a Galerkin projection in terms of Chebyshev polynomials. The neutral stability curves are then plotted for a range of ɛ and Ts values. Preliminary results suggest that increasing Ts has a stabilising effect on both type I and type II stationary instabilities, while small increases in ɛ results in a significant reduction to the critical Reynolds number.

  12. A Chemical Evolution Model for the Fornax Dwarf Spheroidal Galaxy

    Directory of Open Access Journals (Sweden)

    Yuan Zhen

    2016-01-01

    Full Text Available Fornax is the brightest Milky Way (MW dwarf spheroidal galaxy and its star formation history (SFH has been derived from observations. We estimate the time evolution of its gas mass and net inflow and outflow rates from the SFH usinga simple star formation law that relates the star formation rate to the gas mass. We present a chemical evolution model on a 2D mass grid with supernovae (SNe as sources of metal enrichment. We find that a key parameter controlling the enrichment is the mass Mx of the gas to mix with the ejecta from each SN. The choice of Mx depends on the evolution of SN remnants and on the global gas dynamics. It differs between the two types of SNe involved and between the periods before and after Fornax became an MW satellite at time t = tsat. Our results indicate that due to the global gas outflow at t > tsat, part of the ejecta from each SN may directly escape from Fornax. Sample results from our model are presented and compared with data.

  13. ACTINIDE REMOVAL PROCESS SAMPLE ANALYSIS, CHEMICAL MODELING, AND FILTRATION EVALUATION

    Energy Technology Data Exchange (ETDEWEB)

    Martino, C.; Herman, D.; Pike, J.; Peters, T.

    2014-06-05

    Filtration within the Actinide Removal Process (ARP) currently limits the throughput in interim salt processing at the Savannah River Site. In this process, batches of salt solution with Monosodium Titanate (MST) sorbent are concentrated by crossflow filtration. The filtrate is subsequently processed to remove cesium in the Modular Caustic Side Solvent Extraction Unit (MCU) followed by disposal in saltstone grout. The concentrated MST slurry is washed and sent to the Defense Waste Processing Facility (DWPF) for vitrification. During recent ARP processing, there has been a degradation of filter performance manifested as the inability to maintain high filtrate flux throughout a multi-batch cycle. The objectives of this effort were to characterize the feed streams, to determine if solids (in addition to MST) are precipitating and causing the degraded performance of the filters, and to assess the particle size and rheological data to address potential filtration impacts. Equilibrium modelling with OLI Analyzer{sup TM} and OLI ESP{sup TM} was performed to determine chemical components at risk of precipitation and to simulate the ARP process. The performance of ARP filtration was evaluated to review potential causes of the observed filter behavior. Task activities for this study included extensive physical and chemical analysis of samples from the Late Wash Pump Tank (LWPT) and the Late Wash Hold Tank (LWHT) within ARP as well as samples of the tank farm feed from Tank 49H. The samples from the LWPT and LWHT were obtained from several stages of processing of Salt Batch 6D, Cycle 6, Batch 16.

  14. Frequency Modulation Spectroscopy Modeling for Remote Chemical Detection

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, David M.

    2000-09-30

    Frequency modulation (FM) spectroscopy techniques show promise for active infrared remote chemical sensing. FM spectroscopy techniques have reduced sensitivity to optical and electronic noise, and are relatively immune to the effects of various electronic and mechanical drifts. FM systems are responsive to sharp spectral features and can therefore reduce the effects of spectral clutter due to interfering chemicals in the plume or in the atmosphere. The relatively high modulation frequencies used for FM also reduces the effects of albedo (reflectance) and plume variations. Conventional differential absorption lidar (DIAL) systems are performance limited by the noise induced by speckle. Analysis presented in this report shows that FM based sensors may reduce the effects of speckle by one to two orders of magnitude. This can result in reduced dwell times and faster area searches, as well as reducing various forms of spatial clutter. FM systems will require a laser system that is continuously tunable at relatively high frequencies (0.1 to 20 MHz). One promising candidate is the quantum-cascade (QC) laser [1, 2]. The QC laser is potentially capable of power levels on the order of 1 Watt and frequency tuning on the order of 3 - 6 GHz, which is the performance level required for FM spectroscopy based remote sensing. In this report we describe a high-level numerical model for an FM spectroscopy based remote sensing system, and application to two unmanned airborne vehicle (UAV) scenarios. A Predator scenario operating at a slant range of 6.5 km with a 10 cm diameter telescope, and a Global Hawk scenario operating at a range of 30 km with a 20 cm diameter telescope, has been assumed to allow estimation of the performance of potential FM systems.

  15. Tailored Educational Approaches for Consumer Health (TEACH): a model system for addressing health communication.

    Science.gov (United States)

    Cohn, Wendy F; Pannone, Aaron; Schubart, Jane; Lyman, Jason; Kinzie, Mable; Broshek, Donna K; Guterbock, Thomas M; Hartman, David; Mick, David; Bolmey, Armando; Garson, Arthur T

    2006-01-01

    The Consumer Health Education Institute (CHEDI) has developed a model system to improve the quality and effectiveness of patient education and health communication. Through assessment of characteristics and preferences, segmentation into groups and matching with the appropriate materials, we have demonstrated that patients and health consumers have different health information needs and preferences which show promise as a basis for selecting or designing the most appropriate materials or programs.

  16. Sri Lanka's Health Unit Program: A Model of "Selective" Primary Health Care

    Directory of Open Access Journals (Sweden)

    Soma Hewa

    2011-12-01

    Full Text Available This paper argues that the health unit program developed in Sri Lanka in the early twentieth century was an earlier model of selective primary health care promoted by the Rockefeller Foundation in the 1980s in opposition to comprehensive primary health care advocated by the Alma-Ata Declaration of the World Health Organization. A key strategy of the health unit program was to identify the most common and serious infectious diseases in each health unit area and control them through improved sanitation, health education, immunization and treatment with the help of local communities. The health unit program was later introduced to other countries in South and Southeast Asia as part of the Rockefeller Foundation's global campaign to promote public health.

  17. Developing of National Accreditation Model for Rural Health Centers in Iran Health System.

    Directory of Open Access Journals (Sweden)

    Jafar Sadegh Tabrizi

    2013-12-01

    Full Text Available The primary health care has notable effects on community health and accreditation is one of the appropriate evaluation methods that led to health system performance improvement, therefore, this study aims to developing of national accreditation model for rural health centers in Iran Health System.Firstly the suitable accreditation models selected to benchmarking worldwide via systematic review, the related books and medical university's web site surveyed and some interviews hold with experts. Then the obtain standards surveyed from the experts' perspectives via Delphi technique. Finally, the obtainedmodel assessedvia the experts' perspective and pilot study.The researchers identified JCAHO and CCHSA as the most excellent models. The obtained standards and their quality accepted from experts' perspective and pilot study, and finally the number of 55 standards acquired.The designed model has standards with acceptable quality and quantity, and researchers' hopeful that its application in rural health centers led to continues quality improvement.

  18. PNe as observational constraints in chemical evolution models for NGC 6822

    CERN Document Server

    Hernandez-Martinez, Liliana; Peña, Miriam; Peimbert, Manuel

    2011-01-01

    Chemical evolution models are useful for understanding the formation and evolution of stars and galaxies. Model predictions will be more robust as more observational constraints are used. We present chemical evolution models for the dwarf irregular galaxy NGC 6822 using chemical abundances of old and young Planetary Nebulae (PNe) and \\ion{H}{ii} regions as observational constraints. Two sets of chemical abundances, one derived from collisionally excited lines (CELs) and one, from recombination lines (RLs), are used. We try to use our models as a tool to discriminate between both procedures for abundance determinations. In our chemical evolution code, the chemical contribution of low and intermediate mass stars is time delayed, while for the massive stars the chemical contribution follows the instantaneous recycling approximation. Our models have two main free parameters: the mass-loss rate of a well-mixed outflow and the upper mass limit, $M_{up}$, of the initial mass function (IMF). To reproduce the gaseous ...

  19. Introductory lecture: atmospheric organic aerosols: insights from the combination of measurements and chemical transport models.

    Science.gov (United States)

    Pandis, Spyros N; Donahue, Neil M; Murphy, Benjamin N; Riipinen, Ilona; Fountoukis, Christos; Karnezi, Eleni; Patoulias, David; Skyllakou, Ksakousti

    2013-01-01

    The formation, atmospheric evolution, properties, and removal of organic particulate matter remain some of the least understood aspects of atmospheric chemistry despite the importance of organic aerosol (OA) for both human health and climate change. Here, we summarize our recent efforts to deal with the chemical complexity of the tens of thousands of organic compounds in the atmosphere using the volatility-oxygen content framework (often called the 2D-Volatility Basis Set, 2D-VBS). Our current ability to measure the ambient OA concentration as a function of its volatility and oxygen to carbon (O:C) ratio is evaluated. The combination of a thermodenuder, isothermal dilution and Aerosol Mass Spectrometry (AMS) together with a mathematical aerosol dynamics model is a promising approach. The development of computational modules based on the 2D-VBS that can be used in chemical transport models (CTMs) is described. Approaches of different complexity are tested against ambient observations, showing the challenge of simulating the complex chemical evolution of atmospheric OA. The results of the simplest approach describing the net change due to functionalization and fragmentation are quite encouraging, reproducing both the observed OA levels and O : C in a variety of conditions. The same CTM coupled with source-apportionment algorithms can be used to gain insights into the travel distances and age of atmospheric OA. We estimate that the average age of OA near the ground in continental locations is 1-2 days and most of it was emitted (either as precursor vapors or particles) hundreds of kilometers away. Condensation of organic vapors on fresh particles is critical for the growth of these new particles to larger sizes and eventually to cloud condensation nuclei (CCN) sizes. The semivolatile organics currently simulated by CTMs are too volatile to condense on these tiny particles with high curvature. We show that chemical aging reactions converting these semivolatile

  20. A survey of financial planning models for health care organizations.

    Science.gov (United States)

    Coleman, J R; Kaminsky, F C; McGee, F

    1978-01-01

    This paper describes "what if?" financial planning models developed for health care administrators and financial managers to study and evaluate the economic impact of changes in a health care organization's charge structure, operating policies, reimbursement plans, and services and resources. Models for inpatient and outpatient care systems are presented. The models are described in terms of input, output, and application. An assessment of the state of the art of financial planning and prospects for the future of what if?models are given.

  1. Standard Model of Particle Physics--a health physics perspective.

    Science.gov (United States)

    Bevelacqua, J J

    2010-11-01

    The Standard Model of Particle Physics is reviewed with an emphasis on its relationship to the physics supporting the health physics profession. Concepts important to health physics are emphasized and specific applications are presented. The capability of the Standard Model to provide health physics relevant information is illustrated with application of conservation laws to neutron and muon decay and in the calculation of the neutron mean lifetime.

  2. Transtheoretical Model of Health Behavior Change Applied to Voice Therapy

    OpenAIRE

    2007-01-01

    Studies of patient adherence to health behavior programs, such as physical exercise, smoking cessation, and diet, have resulted in the formulation and validation of the Transtheoretical Model (TTM) of behavior change. Although widely accepted as a guide for the development of health behavior interventions, this model has not been applied to vocal rehabilitation. Because resolution of vocal difficulties frequently depends on a patient’s ability to make changes in vocal and health behaviors, th...

  3. National Built Environment Health Impact Assessment Model ...

    Science.gov (United States)

    Behavioral (activity, diet, social interaction) and exposure (air pollution, traffic injury, and noise) related health impacts of land use and transportation investment decisions are becoming better understood and quantified. Research has shown relationships between density, mix, street connectivity, access to parks, shops, transit, presence of sidewalks and bikeways, and healthy food with physical activity, obesity, cardiovascular disease, type II diabetes, and some mental health outcomes. This session demonstrates successful integration of health impact assessment into multiple scenario planning tool platforms. Detailed evidence on chronic disease and related costs associated with contrasting land use and transportation investments are built into a general-purpose module that can be accessed by multiple platforms. Funders, researchers, and end users of the tool will present a detailed description of the key elements of the approach, how it has been applied, and how will evolve. A critical focus will be placed on equity and social justice inherent within the assessment of health disparities that will be featured in the session. Health impacts of community design have significant cost benefit implications. Recent research is now extending relationships between community design features and chronic disease to health care costs. This session will demonstrate the recent application of this evidence on health impacts to the newly adopted Los Angeles Regional Transpo

  4. Simulation Models for Socioeconomic Inequalities in Health: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Niko Speybroeck

    2013-11-01

    Full Text Available Background: The emergence and evolution of socioeconomic inequalities in health involves multiple factors interacting with each other at different levels. Simulation models are suitable for studying such complex and dynamic systems and have the ability to test the impact of policy interventions in silico. Objective: To explore how simulation models were used in the field of socioeconomic inequalities in health. Methods: An electronic search of studies assessing socioeconomic inequalities in health using a simulation model was conducted. Characteristics of the simulation models were extracted and distinct simulation approaches were identified. As an illustration, a simple agent-based model of the emergence of socioeconomic differences in alcohol abuse was developed. Results: We found 61 studies published between 1989 and 2013. Ten different simulation approaches were identified. The agent-based model illustration showed that multilevel, reciprocal and indirect effects of social determinants on health can be modeled flexibly. Discussion and Conclusions: Based on the review, we discuss the utility of using simulation models for studying health inequalities, and refer to good modeling practices for developing such models. The review and the simulation model example suggest that the use of simulation models may enhance the understanding and debate about existing and new socioeconomic inequalities of health frameworks.

  5. E-health stakeholders experiences with clinical modelling and standardizations.

    Science.gov (United States)

    Gøeg, Kirstine Rosenbeck; Elberg, Pia Britt; Højen, Anne Randorff

    2015-01-01

    Stakeholders in e-health such as governance officials, health IT-implementers and vendors have to co-operate to achieve the goal of a future-proof interoperable e-health infrastructure. Co-operation requires knowledge on the responsibility and competences of stakeholder groups. To increase awareness on clinical modeling and standardization we conducted a workshop for Danish and a few Norwegian e-health stakeholders' and made them discuss their views on different aspects of clinical modeling using a theoretical model as a point of departure. Based on the model, we traced stakeholders' experiences. Our results showed there was a tendency that stakeholders were more familiar with e-health requirements than with design methods, clinical information models and clinical terminology as they are described in the scientific literature. The workshop made it possible for stakeholders to discuss their roles and expectations to each other.

  6. Modelling the chemical evolution of star forming filaments

    Science.gov (United States)

    Seifried, D.; Walch, S.

    2016-05-01

    We present simulations of star forming filaments incorporating - to our knowledge - the largest chemical network used to date on-the-fly in a 3D-MHD simulation. The network contains 37 chemical species and about 300 selected reaction rates. For this we use the newly developed package KROME (Grassi et al. [4]). Our results demonstrate the feasibility of using such a complex chemical network in 3D-MHD simulations on modern supercomputers. We perform simulations with different strengths of the interstellar radiation field and the cosmic ray ionisation rate and find chemical and physical results in accordance with observations and other recent numerical work.

  7. Modelling the chemical evolution of star forming filaments

    CERN Document Server

    Seifried, D

    2015-01-01

    We present simulations of star forming filaments incorporating - to our knowledge - the largest chemical network used to date on-the-fly in a 3D-MHD simulation. The network contains 37 chemical species and about 300 selected reaction rates. For this we use the newly developed package KROME (Grassi et al. 2014). Our results demonstrate the feasibility of using such a complex chemical network in 3D-MHD simulations on modern supercomputers. We perform simulations with different strengths of the interstellar radiation field and the cosmic ray ionisation rate and find chemical and physical results in accordance with observations and other recent numerical work.

  8. Information resources for assessing health effects from chemical exposure: Challenges, priorities, and future issues

    Energy Technology Data Exchange (ETDEWEB)

    Seigel, S. [National Library of Medicine, Bethesda, MD (United States)

    1990-12-31

    Issues related to developing information resources for assessing the health effects from chemical exposure include the question of how to address the individual political issues relevant to identifying and determining the timeliness, scientific credibility, and completeness of such kinds of information resources. One of the important ways for agencies to share information is through connection tables. This type of software is presently being used to build information products for some DHHS agencies. One of the challenges will be to convince vendors of data of the importance of trying to make data files available to communities that need them. In the future, information processing will be conducted with neural networks, object-oriented database management systems, and fuzzy-set technologies, and meta analysis techniques.

  9. Human and animal health risk assessments of chemicals in the food chain: Comparative aspects and future perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Dorne, J.L.C.M., E-mail: jean-lou.dorne@efsa.europa.eu [Emerging Risk Unit, Via Carlo Magno 1A, 43126 Parma (Italy); Fink-Gremmels, J. [Utrecht University, Faculty of Veterinary Medicine, Institute for Risk Assessment Sciences, Yalelaan 104, 3584 CM Utrecht (Netherlands)

    2013-08-01

    Chemicals from anthropogenic and natural origins enter animal feed, human food and water either as undesirable contaminants or as part of the components of a diet. Over the last five decades, considerable efforts and progress to develop methodologies to protect humans and animals against potential risks associated with exposure to such potentially toxic chemicals have been made. This special issue presents relevant methodological developments and examples of risk assessments of undesirable substances in the food chain integrating the animal health and the human health perspective and refers to recent Opinions of the Scientific Panel on Contaminants in the Food Chain (CONTAM) of the European Food Safety Authority (EFSA). This introductory review aims to give a comparative account of the risk assessment steps used in human health and animal health risk assessments for chemicals in the food chain and provides a critical view of the data gaps and future perspectives for this cross-disciplinary field. - Highlights: ► Principles of human and animal health risk assessment. ► Data gaps for each step of animal health risk assessment. ► Implications of animal risk assessment on human risk assessment. ► Future perspectives on chemical risk assessment.

  10. In situ chemical sensing for hydrothermal plume mapping and modeling

    Science.gov (United States)

    Fukuba, T.; Kusunoki, T.; Maeda, Y.; Shitashima, K.; Kyo, M.; Fujii, T.; Noguchi, T.; Sunamura, M.

    2012-12-01

    Detection, monitoring, and mapping of biogeochemical anomalies in seawater such as temperature, salinity, turbidity, oxidation-reduction potential, and pH are essential missions to explore undiscovered hydrothermal sites and to understand distribution and behavior of hydrothermal plumes. Utilization of reliable and useful in situ sensors has been widely accepted as a promised approach to realize a spatiotemporally resolved mapping of anomalies without water sampling operations. Due to remarkable progresses of sensor technologies and its relatives, a number of highly miniaturized and robust chemical sensors have been proposed and developed. We have been developed, evaluated, and operated a compact ISFET (Ion-Sensitive Field-Effect Transistor)-based chemical sensors for ocean environmental sensing purposes. An ISFET has advantages against conventional glass-based electrodes on its faster response, robustness, and potential on miniaturization, and thus variety of chemical sensors has been already on the market. In this study, ISFET-based standalone pH sensors with a solid-state Cl-ISE as a reference electrode were mounted on various platforms and operated to monitor the pH anomalies in deep-sea environment at the Kairei, Edmond, and surrounding hydrothermal sites in the southern Central Indian Ridge area during KH10-06 scientific cruise (Nov. 2010), supported by project TAIGA (Trans-crustal Advection and In situ biogeochemical processes of Global sub-seafloor Aquifer). Up to three pH sensors were mounted on a wire-lined CTD/RMS (Rosette Multiple Sampler), dredge sampler, a series of MTD plankton nets, and VMPS (Vertical Multiple-operating Plankton Sampler). A standalone temperature sensor was bundled and operated with the pH sensor when they were mounted on the dredge sampler, MTD plankton nets, and VMPS. An AUV equipped with the pH sensor was also operated for hydrothermal activity survey operations. As a result of Tow-Yo intersect operations of the CTD

  11. Embedded Fragments from U.S. Military Personnel—Chemical Analysis and Potential Health Implications

    Directory of Open Access Journals (Sweden)

    José A. Centeno

    2014-01-01

    Full Text Available Background: The majority of modern war wounds are characterized by high-energy blast injuries containing a wide range of retained foreign materials of a metallic or composite nature. Health effects of retained fragments range from local or systemic toxicities to foreign body reactions or malignancies, and dependent on the chemical composition and corrosiveness of the fragments in vivo. Information obtained by chemical analysis of excised fragments can be used to guide clinical decisions regarding the need for fragment removal, to develop therapeutic interventions, and to better anticipate future medical problems from retained fragment related injuries. In response to this need, a new U.S Department of Defense (DoD directive has been issued requiring characterization of all removed fragments to provide a database of fragment types occurring in combat injuries. Objectives: The objective of this study is to determine the chemical composition of retained embedded fragments removed from injured military personnel, and to relate results to histological findings in tissue adjacent to fragment material. Methods: We describe an approach for the chemical analysis and characterization of retained fragments and adjacent tissues, and include case examples describing fragments containing depleted uranium (DU, tungsten (W, lead (Pb, and non-metal foreign bodies composed of natural and composite materials. Fragments obtained from four patients with penetrating blast wounds to the limbs were studied employing a wide range of chemical and microscopy techniques. Available adjacent tissues from three of the cases were histologically, microscopically, and chemically examined. The physical and compositional properties of the removed foreign material surfaces were examined with energy dispersive x-ray fluorescence spectrometry (EDXRF, scanning electron microscopy (SEM, laser ablation inductively-coupled plasma mass-spectrometry (LA-ICP-MS, and confocal laser Raman

  12. The shifting landscape of health care: toward a model of health care empowerment.

    Science.gov (United States)

    Johnson, Mallory O

    2011-02-01

    In a rapidly changing world of health care information access and patients' rights, there is limited conceptual infrastructure available to understand how people approach and engage in treatment of medical conditions. The construct of health care empowerment is defined as the process and state of being engaged, informed, collaborative, committed, and tolerant of uncertainty regarding health care. I present a model in which health care empowerment is influenced by an interplay of cultural, social, and environmental factors; personal resources; and intrapersonal factors. The model offers a framework to understand patient and provider roles in facilitating health care empowerment and presents opportunities for investigation into the role of health care empowerment in multiple outcomes across populations and settings, including inquiries into the sources and consequences of health disparities.

  13. The Relationship between Spiritual Health and other Dimensions of Health: Presentation of a Model

    Directory of Open Access Journals (Sweden)

    Akram Heidari

    2016-06-01

    Full Text Available Attitudes to humankind will have different effects on health service delivery. Health might used to be intended to provide physical health in the past; today, however, many researchers and clinicians consider the concept health to be beyond physical health. In support of this claim, it is enough to indicate that the bio-psycho-social model has for years been held by scientific communities to be a fully admitted model. However, the missing ring in this model, as suggested by many, is the spiritual health. In recent years, the relationship between spirituality and clinical interventions with a comprehensive focus on health has been under increasing scrutiny. Although different models have been presented for investigation of the relationship between spiritual health and other dimensions, the fundamental challenge in this regard is the actual place of spiritual health compared with other dimensions. In this article, attempts are made to address the position and weight of spiritual health from the Islam’s point of view.

  14. Mental health triage: towards a model for nursing practice.

    Science.gov (United States)

    Sands, N

    2007-05-01

    Mental health triage/duty services play a pivotal role in the current framework for mental health service delivery in Victoria and other states of Australia. Australia is not alone in its increasing reliance on mental health triage as a model of psychiatric service provision; at a global level, there appears to be an emerging trend to utilize mental health triage services staffed by nurses as a cost-effective means of providing mental health care to large populations. At present, nurses comprise the greater proportion of the mental health triage workforce in Victoria and, as such, are performing the majority of point-of-entry mental health assessment across the state. Although mental health triage/duty services have been operational for nearly a decade in some regional healthcare sectors of Victoria, there is little local or international research on the topic, and therefore a paucity of established theory to inform and guide mental health triage practice and professional development. The discussion in this paper draws on the findings and recommendations of PhD research into mental health triage nursing in Victoria, to raise discussion on the need to develop theoretical models to inform and guide nursing practice. The paper concludes by presenting a provisional model for mental health triage nursing practice.

  15. Sustainable Organic Farming For Environmental Health A Social Development Model

    Directory of Open Access Journals (Sweden)

    Ijun Rijwan Susanto

    2015-05-01

    Full Text Available ABSTRACT In this study the researcher attempted 1 to understand the basic features of organic farming in The Paguyuban Pasundans Cianjur 2 to describe and understand how the stakeholders were are able to internalize the challenges of organic farming on their lived experiences in the community 3 to describe and understand how the stakeholders were are able to internalize and applied the values of benefits of organic farming in support of environmental health on their lived experiences in the community 4 The purpose was to describe and understand how the stakeholders who are able to articulate their ideas regarding the model of sustainable organic farming 5 The Policy Recommendation for Organic Farming. The researcher employed triangulation thorough finding that provides breadth and depth to an investigation offering researchers a more accurate picture of the phenomenon. In the implementation of triangulation researchers conducted several interviews to get saturation. After completion of the interview results are written compiled and shown to the participants to check every statement by every participant. In addition researchers also checked the relevant documents and direct observation in the field The participants of this study were the stakeholders namely 1 The leader of Paguyuban Pasundans Organic Farmer Cianjur PPOFC 2 Members of Paguyuban Pasundans Organic FarmersCianjur 3 Leader of NGO 4 Government officials of agriculture 5 Business of organic food 6 and Consumer of organic food. Generally the findings of the study revealed the following 1 PPOFC began to see the reality as the impact of modern agriculture showed in fertility problems due to contaminated soil by residues of agricultural chemicals such as chemical fertilizers and chemical pesticides. So he wants to restore the soil fertility through environmentally friendly of farming practices 2 the challenges of organic farming on their lived experiences in the community farmers did not

  16. Modeling regional secondary organic aerosol using the Master Chemical Mechanism

    Science.gov (United States)

    Li, Jingyi; Cleveland, Meredith; Ziemba, Luke D.; Griffin, Robert J.; Barsanti, Kelley C.; Pankow, James F.; Ying, Qi

    2015-02-01

    A modified near-explicit Master Chemical Mechanism (MCM, version 3.2) with 5727 species and 16,930 reactions and an equilibrium partitioning module was incorporated into the Community Air Quality Model (CMAQ) to predict the regional concentrations of secondary organic aerosol (SOA) from volatile organic compounds (VOCs) in the eastern United States (US). In addition to the semi-volatile SOA from equilibrium partitioning, reactive surface uptake processes were used to simulate SOA formation due to isoprene epoxydiol, glyoxal and methylglyoxal. The CMAQ-MCM-SOA model was applied to simulate SOA formation during a two-week episode from August 28 to September 7, 2006. The southeastern US has the highest SOA, with a maximum episode-averaged concentration of ∼12 μg m-3. Primary organic aerosol (POA) and SOA concentrations predicted by CMAQ-MCM-SOA agree well with AMS-derived hydrocarbon-like organic aerosol (HOA) and oxygenated organic aerosol (OOA) urban concentrations at the Moody Tower at the University of Houston. Predicted molecular properties of SOA (O/C, H/C, N/C and OM/OC ratios) at the site are similar to those reported in other urban areas, and O/C values agree with measured O/C at the same site. Isoprene epoxydiol is predicted to be the largest contributor to total SOA concentration in the southeast US, followed by methylglyoxal and glyoxal. The semi-volatile SOA components are dominated by products from β-caryophyllene oxidation, but the major species and their concentrations are sensitive to errors in saturation vapor pressure estimation. A uniform decrease of saturation vapor pressure by a factor of 100 for all condensable compounds can lead to a 150% increase in total SOA. A sensitivity simulation with UNIFAC-calculated activity coefficients (ignoring phase separation and water molecule partitioning into the organic phase) led to a 10% change in the predicted semi-volatile SOA concentrations.

  17. Marketing guidelines for providers of mental health and chemical dependency services--responding to changes in the packaging and purchase of behavioral health benefits.

    Science.gov (United States)

    Oss, M E

    1993-01-01

    In summary, the mental health and chemical dependency market has changed to the point that providers and programs of any type can no longer survey financially without well-developed marketing strategies--including a conscious decision about target markets and niches within those markets. Behavioral health providers and programs need to thoroughly evaluate their internal resources, along with possible market niches, in order to develop these strategies.

  18. Leadership models in health care - a case for servant leadership.

    Science.gov (United States)

    Trastek, Victor F; Hamilton, Neil W; Niles, Emily E

    2014-03-01

    Our current health care system is broken and unsustainable. Patients desire the highest quality care, and it needs to cost less. To regain public trust, the health care system must change and adapt to the current needs of patients. The diverse group of stakeholders in the health care system creates challenges for improving the value of care. Health care providers are in the best position to determine effective ways of improving the value of care. To create change, health care providers must learn how to effectively lead patients, those within health care organizations, and other stakeholders. This article presents servant leadership as the best model for health care organizations because it focuses on the strength of the team, developing trust and serving the needs of patients. As servant leaders, health care providers may be best equipped to make changes in the organization and in the provider-patient relationship to improve the value of care for patients.

  19. Models for risk assessment of reactive chemicals in aquatic toxicology

    NARCIS (Netherlands)

    Freidig, Andreas Peter

    2001-01-01

    A quantitative structure property relationship (QSPR) for a,b-unsaturated carboxylates (mainly acrylates and methacrylates) was established in chapter 2. Chemical reaction rate constants were measured for 12 different chemicals with three different nucleophiles, namely H 2 O, OH - and glutathione (G

  20. Health assessment for Pasley Solvents and Chemical, Garden City, New York, Region 2. CERCLIS No. NYD991292004. Preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    1989-06-01

    The Pasley Solvents and Chemicals site, a National Priorities List site, is located in the Town of Hempstead, immediately east of the Village of Garden City in Nassau County, New York. Between 1969 and 1982, Pasley operated a chemical distribution facility on the lot, occasionally storing waste chemicals. Prior to this, Commander Oil used the site for gasoline storage and fuel oil distribution. The Nassau County Health Department (NCHD) investigated the site in 1981 and found the on-site soil and ground water to be contaminated with organic solvents and petroleum products. On-site sampling by NCHD and the owner has revealed organic chemicals and petroleum products in both soil and ground water. Six chlorinated solvents and four aromatic compounds are in ground water above the part per million. The site is a potential threat to public health.

  1. 3 Lectures: "Lagrangian Models", "Numerical Transport Schemes", and "Chemical and Transport Models"

    Science.gov (United States)

    Douglass, A.

    2005-01-01

    The topics for the three lectures for the Canadian Summer School are Lagrangian Models, numerical transport schemes, and chemical and transport models. In the first lecture I will explain the basic components of the Lagrangian model (a trajectory code and a photochemical code), the difficulties in using such a model (initialization) and show some applications in interpretation of aircraft and satellite data. If time permits I will show some results concerning inverse modeling which is being used to evaluate sources of tropospheric pollutants. In the second lecture I will discuss one of the core components of any grid point model, the numerical transport scheme. I will explain the basics of shock capturing schemes, and performance criteria. I will include an example of the importance of horizontal resolution to polar processes. We have learned from NASA's global modeling initiative that horizontal resolution matters for predictions of the future evolution of the ozone hole. The numerical scheme will be evaluated using performance metrics based on satellite observations of long-lived tracers. The final lecture will discuss the evolution of chemical transport models over the last decade. Some of the problems with assimilated winds will be demonstrated, using satellite data to evaluate the simulations.

  2. AB159. Endocrine disrupting chemicals: toxicological risk assessment in vivo and in vitro models

    Science.gov (United States)

    Thuy, Vo Thi Bich; Nguyen Binh, Le Thi; Phuong Oanh, Kim Thi; Van Hai, Nong

    2015-01-01

    In several studies, scientists asserted that many of endocrine disruptors (EDs), which have been involved in developmental, reproductive, neural, immunological, and other problems in wildlife and laboratory animals. Some environmental EDs, such as di-(2-ethylhexyl) phthalate (DEHP), flutamide (Flu), parabens, are used in many products in life and environment. However, the adverse effects caused by EDs can be temporary or permanent and the mechanism(s) through which these chemicals elicit their effects on biological systems of human and animal health is not clearly understood. The specific aim of this study is to evaluate endocrine disrupting chemicals-induced impact on the male or female reproductive system. An attempt is also made to elucidate the impact of these EDs in an in vitro model, i.e., GH3 rat pituitary cell line. A great deal of work has been carried out on the toxicity of phthalate, Flu, parabens in vivo and in vitro models. In brief, studies have been indicated that long-term and short-term exposure to various endocrine disrupting compounds (i.e., DEHP, Flu, parabens) during development stage (i.e., gestation, neonatal, immature, peripubertal) were done to find alternative dysfunctions later in animal life. The development and function of male or female reproductive tract showed many abnormalities, e.g., menstrual cycle irregularities; impaired fertility, endometriosis, and polycystic ovarian syndrome in female or morphological and functional gonadal dysfunction, e.g., infertility and decreased libido, congenital malformations (altered embryonic and fetal intrauterine development) and testicular dysgenesis syndrome in male. In addition, the differential gene expression patterns by microarray analysis following EDs exposure were found, particularly in steroid hormone synthesis, androgen and/or estrogen synthesis, and sex determination-related gene. On the other hand, studies revealed that parabens, a weak estrogenic chemical, exerted their actions on

  3. [Empowering the family-center health model: the toy library as a health promotion platform].

    Science.gov (United States)

    Huang, Yu-Chu; Tsai, Yen-Chih

    2011-02-01

    Facing the lowest birth rates in its history, Taiwan is increasingly recognizing the centrality of children's healthcare needs to effective family care. The World Health Organization's goal of health for all emphasizes health promotion. However, little research attention has been given to how families actively promote personal health in everyday life. This article considers 'family-centric' healthcare, with a particular emphasis on children's health and well-being and the mother health promotion model. Authors employ a 'toy library' as the health promotion platform to build community interaction and empower the health enhancement process. Results suggested the following: 1. The fixed-point type toy library may be an effective tool in a health promotion strategy; 2. A model may be developed for rural institution agencies; 3. Cooperation may be facilitated using a medical service vehicle; 4. The love bag program can serve extended purposes. The authors found that the empowerment and growth of tribal mothers is a key element to facilitate the successful development of their children. Based on findings, the implementation of a toy library as the platform to build community-based health promotion model is suggested.

  4. Thermochemical model for shock-induced chemical reactions in porous thermite: The heat detonation model

    Energy Technology Data Exchange (ETDEWEB)

    Boslough, M.B.

    1989-01-01

    A thermochemical model has been developed that treats a shock-induced solid state chemical reaction as a special type of detonation, called a ''heat detonation'' to distinguish it from an ordinary explosive detonation and describe the final form that the chemical energy takes. According to shock temperature measurements, chemical energy can be released from porous reactive solids on a time scale shorter than shock-transit times in laboratory samples. By comparing the experimental shock temperature for porous thermite to that calculated by the model, the amount of thermite reacted when shocked to about 4 GPa was estimated to be between 60 and 70%. Calculated shock temperatures are extremely strong functions of the extent of reaction, but are relatively insensitive to the initial porosity and amount of volatile impurities. Thus, shock temperature measurements are the most useful for real-time studies of shock-induced exothermic chemical reactions in solids. 11 refs., 5 figs., 1 tab.

  5. World Health Organization estimates of the global and regional disease burden of four foodborne chemical toxins, 2010: a data synthesis.

    Science.gov (United States)

    Gibb, Herman; Devleesschauwer, Brecht; Bolger, P Michael; Wu, Felicia; Ezendam, Janine; Cliff, Julie; Zeilmaker, Marco; Verger, Philippe; Pitt, John; Baines, Janis; Adegoke, Gabriel; Afshari, Reza; Liu, Yan; Bokkers, Bas; van Loveren, Henk; Mengelers, Marcel; Brandon, Esther; Havelaar, Arie H; Bellinger, David

    2015-01-01

    Background Chemical exposures have been associated with a variety of health effects; however, little is known about the global disease burden from foodborne chemicals. Food can be a major pathway for the general population's exposure to chemicals, and for some chemicals, it accounts for almost 100% of exposure.  Methods and Findings Groups of foodborne chemicals, both natural and anthropogenic, were evaluated for their ability to contribute to the burden of disease.  The results of the analyses on four chemicals are presented here - cyanide in cassava, peanut allergen, aflatoxin, and dioxin.  Systematic reviews of the literature were conducted to develop age- and sex-specific disease incidence and mortality estimates due to these chemicals.  From these estimates, the numbers of cases, deaths and disability adjusted life years (DALYs) were calculated.  For these four chemicals combined, the total number of illnesses, deaths, and DALYs in 2010 is estimated to be 339,000 (95% uncertainty interval [UI]: 186,000-1,239,000); 20,000 (95% UI: 8,000-52,000); and 1,012,000 (95% UI: 562,000-2,822,000), respectively.  Both cyanide in cassava and aflatoxin are associated with diseases with high case-fatality ratios.  Virtually all human exposure to these four chemicals is through the food supply.  Conclusion Chemicals in the food supply, as evidenced by the results for only four chemicals, can have a significant impact on the global burden of disease. The case-fatality rates for these four chemicals range from low (e.g., peanut allergen) to extremely high (aflatoxin and liver cancer).  The effects associated with these four chemicals are neurologic (cyanide in cassava), cancer (aflatoxin), allergic response (peanut allergen), endocrine (dioxin), and reproductive (dioxin).

  6. A gandhian model of health: Looking at Alzheimer's disease.

    Science.gov (United States)

    Weaver, R C

    1987-03-01

    Mahatma Gandhi was often criticized for mixing religion, politics, economics, and health. However, it was his very insistence on the fundamental interrelationship of all aspects of life that gives his ideas such relevance for today's problems. This paper focuses on his views on health and attempts to develop a Gandhian model of health that has relevance for us today. This model is then specifically applied to the vexing problem of Alzheimer's disease, and an ongoing therapeutic trial that is based on this model is described.

  7. A review of operational, regional-scale, chemical weather forecasting models in Europe

    Directory of Open Access Journals (Sweden)

    J. Kukkonen

    2012-01-01

    Full Text Available Numerical models that combine weather forecasting and atmospheric chemistry are here referred to as chemical weather forecasting models. Eighteen operational chemical weather forecasting models on regional and continental scales in Europe are described and compared in this article. Topics discussed in this article include how weather forecasting and atmospheric chemistry models are integrated into chemical weather forecasting systems, how physical processes are incorporated into the models through parameterization schemes, how the model architecture affects the predicted variables, and how air chemistry and aerosol processes are formulated. In addition, we discuss sensitivity analysis and evaluation of the models, user operational requirements, such as model availability and documentation, and output availability and dissemination. In this manner, this article allows for the evaluation of the relative strengths and weaknesses of the various modelling systems and modelling approaches. Finally, this article highlights the most prominent gaps of knowledge for chemical weather forecasting models and suggests potential priorities for future research directions, for the following selected focus areas: emission inventories, the integration of numerical weather prediction and atmospheric chemical transport models, boundary conditions and nesting of models, data assimilation of the various chemical species, improved understanding and parameterization of physical processes, better evaluation of models against data and the construction of model ensembles.

  8. Fate Model for Organic Chemicals in Sewage Treatment Plants

    DEFF Research Database (Denmark)

    Mikkelsen, J.

    Miljøprojekt, 308; I tilknytning til hovedrapporten Environmental Exposure Assessment of Chemicals (Miljøprojekt, 306) er udgivet i alt 5 tekniske bilagsrapporter, alle i serien Miljøprojekt.......Miljøprojekt, 308; I tilknytning til hovedrapporten Environmental Exposure Assessment of Chemicals (Miljøprojekt, 306) er udgivet i alt 5 tekniske bilagsrapporter, alle i serien Miljøprojekt....

  9. Model reduction for stochastic chemical systems with abundant species

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Stephen; Cianci, Claudia; Grima, Ramon [School of Biological Sciences, University of Edinburgh, Mayfield Road, Edinburgh EH93JR, Scotland (United Kingdom)

    2015-12-07

    Biochemical processes typically involve many chemical species, some in abundance and some in low molecule numbers. We first identify the rate constant limits under which the concentrations of a given set of species will tend to infinity (the abundant species) while the concentrations of all other species remains constant (the non-abundant species). Subsequently, we prove that, in this limit, the fluctuations in the molecule numbers of non-abundant species are accurately described by a hybrid stochastic description consisting of a chemical master equation coupled to deterministic rate equations. This is a reduced description when compared to the conventional chemical master equation which describes the fluctuations in both abundant and non-abundant species. We show that the reduced master equation can be solved exactly for a number of biochemical networks involving gene expression and enzyme catalysis, whose conventional chemical master equation description is analytically impenetrable. We use the linear noise approximation to obtain approximate expressions for the difference between the variance of fluctuations in the non-abundant species as predicted by the hybrid approach and by the conventional chemical master equation. Furthermore, we show that surprisingly, irrespective of any separation in the mean molecule numbers of various species, the conventional and hybrid master equations exactly agree for a class of chemical systems.

  10. A simple model for the distribution and fate of organic chemicals in a landfill: MOCLA

    DEFF Research Database (Denmark)

    Kjeldsen, Peter; Christensen, Thomas Højlund

    2001-01-01

    of degradation and transformation in the landfill. Local equilibrium is assumed for the distribution of the chemicals in the landfill as expressed by Henry’s Law for the leachate-gas interface, and by the linear partition coefficient based on the waste solid organic carbon content for the waste......A simple mathematical model (MOCLA: Model for Organic Chemicals in Landfills) is presented, describing the distribution of organic chemicals between leachate, gas and solid waste. The model also predicts the fate of the chemicals in terms of emissions with leachate and landfill gas and in terms......-leachate interface. Degradation of the chemicals is expressed as a first order reaction. Annual specific leachate and gas generation data in combination with data on landfill area and volume allow for prediction of main emission routes. Model simulations involving two landfill scenarios for a number of chemicals...

  11. Models of education in medicine, public health, and engineering.

    Science.gov (United States)

    Garcia, Patricia; Armstrong, Robert; Zaman, Muhammad H

    2014-09-12

    Discussion on global health in both the academic and the public domain has focused largely on research, capacity building, and service delivery. Although these efforts along with financial commitments from public and private partners have contributed to a broader appreciation and understanding of global health challenges, the reflection of global health in academic training has largely been lacking. However, integrative models are beginning to appear.

  12. Discovering health topics in social media using topic models.

    Directory of Open Access Journals (Sweden)

    Michael J Paul

    Full Text Available By aggregating self-reported health statuses across millions of users, we seek to characterize the variety of health information discussed in Twitter. We describe a topic modeling framework for discovering health topics in Twitter, a social media website. This is an exploratory approach with the goal of understanding what health topics are commonly discussed in social media. This paper describes in detail a statistical topic model created for this purpose, the Ailment Topic Aspect Model (ATAM, as well as our system for filtering general Twitter data based on health keywords and supervised classification. We show how ATAM and other topic models can automatically infer health topics in 144 million Twitter messages from 2011 to 2013. ATAM discovered 13 coherent clusters of Twitter messages, some of which correlate with seasonal influenza (r = 0.689 and allergies (r = 0.810 temporal surveillance data, as well as exercise (r =  .534 and obesity (r =  -.631 related geographic survey data in the United States. These results demonstrate that it is possible to automatically discover topics that attain statistically significant correlations with ground truth data, despite using minimal human supervision and no historical data to train the model, in contrast to prior work. Additionally, these results demonstrate that a single general-purpose model can identify many different health topics in social media.

  13. QSAR modeling of toxicity of diverse organic chemicals to Daphnia magna using 2D and 3D descriptors

    Energy Technology Data Exchange (ETDEWEB)

    Kar, Supratik [Drug Theoretics and Cheminformatics Laboratory, Department of Pharmaceutical Technology, Jadavpur University, Raja S C Mullick Road, Kolkata 700032 (India); Roy, Kunal, E-mail: kunalroy_in@yahoo.com [Drug Theoretics and Cheminformatics Laboratory, Department of Pharmaceutical Technology, Jadavpur University, Raja S C Mullick Road, Kolkata 700032 (India)

    2010-05-15

    One of the major economic alternatives to experimental toxicity testing is the use of quantitative structure-activity relationships (QSARs) which are used in formulating regulatory decisions of environmental protection agencies. In this background, we have modeled a large diverse group of 297 chemicals for their toxicity to Daphnia magna using mechanistically interpretable descriptors. Three-dimensional (3D) (electronic and spatial) and two-dimensional (2D) (topological and information content indices) descriptors along with physicochemical parameter log K{sub o/w} (n-octanol/water partition coefficient) and structural descriptors were used as predictor variables. The QSAR models were developed by stepwise multiple linear regression (MLR), partial least squares (PLS), genetic function approximation (GFA), and genetic PLS (G/PLS). All the models were validated internally and externally. Among several models developed using different chemometric tools, the best model based on both internal and external validation characteristics was a PLS equation with 7 descriptors and three latent variables explaining 67.8% leave-one-out predicted variance and 74.1% external predicted variance. The PLS model suggests that higher lipophilicity and electrophilicity, less negative charge surface area and presence of ether linkage, hydrogen bond donor groups and acetylenic carbons are responsible for greater toxicity of chemicals. The developed model may be used for prediction of toxicity, safety and risk assessment of chemicals to achieve better ecotoxicological management and prevent adverse health consequences.

  14. The Culture-Work-Health Model and Work Stress.

    Science.gov (United States)

    Peterson, Michael; Wilson, John F.

    2002-01-01

    Examines the role of organizational culture in the etiology of workplace stress through the framework of the Culture-Work- Health model. A review of relevant business and health literature indicates that culture is an important component of work stress and may be a key to creating effective organizational stress interventions. (SM)

  15. Dental Health Care Models of Southwest Cultures. Final Report.

    Science.gov (United States)

    Pettibone, Timothy J.; Solis, Enrique, Jr.

    The major goal of this research was the development and validation of cultural models of dental health practices. The specific objectives were to determine if 3 cultural groups (American Indians, Mexican Americans, and Anglo Americans) differ in the dental health hygiene indices, characteristics, psychological factors, or social factors; to…

  16. Developing explanatory models of health inequalities in childhood dental caries

    DEFF Research Database (Denmark)

    Pine, Cynthia M; Adair, Pauline M; Petersen, Poul Erik

    2004-01-01

    OBJECTIVE: Long-term aim is to determine optimum interventions to reduce dental caries in children in disadvantaged communities and minimise the effects of exclusion from health care systems, of ethnic diversity, and health inequalities. DESIGN: Generation of initial explanatory models, study pro...

  17. Six challenges in modelling for public health policy

    Directory of Open Access Journals (Sweden)

    C.J.E. Metcalf

    2015-03-01

    Full Text Available The World Health Organisation's definition of public health refers to all organized measures to prevent disease, promote health, and prolong life among the population as a whole (World Health Organization, 2014. Mathematical modelling plays an increasingly important role in helping to guide the most high impact and cost-effective means of achieving these goals. Public health programmes are usually implemented over a long period of time with broad benefits to many in the community. Clinical trials are seldom large enough to capture these effects. Observational data may be used to evaluate a programme after it is underway, but have limited value in helping to predict the future impact of a proposed policy. Furthermore, public health practitioners are often required to respond to new threats, for which there is little or no previous data on which to assess the threat. Computational and mathematical models can help to assess potential threats and impacts early in the process, and later aid in interpreting data from complex and multifactorial systems. As such, these models can be critical tools in guiding public health action. However, there are a number of challenges in achieving a successful interface between modelling and public health. Here, we discuss some of these challenges.

  18. A new model for health care delivery

    Directory of Open Access Journals (Sweden)

    Kepros John P

    2009-04-01

    Full Text Available Abstract Background The health care delivery system in the United States is facing cost and quality pressures that will require fundamental changes to remain viable. The optimal structures of the relationships between the hospital, medical school, and physicians have not been determined but are likely to have a large impact on the future of healthcare delivery. Because it is generally agreed that academic medical centers will play a role in the sustainability of this future system, a fundamental understanding of the relative contributions of the stakeholders is important as well as creativity in developing novel strategies to achieve a shared vision. Discussion Core competencies of each of the stakeholders (the hospital, the medical school and the physicians must complement the others and should act synergistically. At the same time, the stakeholders should determine the common core values and should be able to make a meaningful contribution to the delivery of health care. Summary Health care needs to achieve higher quality and lower cost. Therefore, in order for physicians, medical schools, and hospitals to serve the needs of society in a gratifying way, there will need to be change. There needs to be more scientific and social advances. It is obvious that there is a real and urgent need for relationship building among the professionals whose duty it is to provide these services.

  19. A mathematical model and simulation results of plasma enhanced chemical vapor deposition of silicon nitride films

    NARCIS (Netherlands)

    Konakov, S.A.; Krzhizhanovskaya, V.V.

    2015-01-01

    We developed a mathematical model of Plasma Enhanced Chemical Vapor Deposition (PECVD) of silicon nitride thin films from SiH4-NH3-N2-Ar mixture, an important application in modern materials science. Our multiphysics model describes gas dynamics, chemical physics, plasma physics and electrodynamics.

  20. CONSISTENT USE OF THE KALMAN FILTER IN CHEMICAL TRANSPORT MODELS (CTMS) FOR DEDUCING EMISSIONS

    Science.gov (United States)

    Past research has shown that emissions can be deduced using observed concentrations of a chemical, a Chemical Transport Model (CTM), and the Kalman filter in an inverse modeling application. An expression was derived for the relationship between the "observable" (i.e., the con...

  1. Organism and population-level ecological models for chemical risk assessment

    Science.gov (United States)

    Ecological risk assessment typically focuses on animal populations as endpoints for regulatory ecotoxicology. Scientists at USEPA are developing models for animal populations exposed to a wide range of chemicals from pesticides to emerging contaminants. Modeled taxa include aquat...

  2. Probabilistic Health Risk Assessment of Chemical Mixtures: Importance of Travel Times and Connectivity

    Science.gov (United States)

    Henri, Christopher V.; Fernàndez-Garcia, Daniel; de Barros, Felipe P. J.

    2014-05-01

    Subsurface contamination cases giving rise to groundwater pollutions are extensively found in all industrialized countries. Under this pressure, risk assessment methods play an important role in population protection by (1) quantifying the potential impact on human health of an aquifer contamination and (2) helping and driving decisions of groundwater-resource managers. Many reactive components such as chlorinated solvents or nitrates potentially experience attenuation processes under common geochemical conditions. This represents an attractive and extensively used remediation solution but leads often to the production of by-products before to reach a harmless chemical form. This renders mixtures of contaminants a common issue for groundwater resources managers. In this case, the threat posed by these contaminants to human health at a given sensitive location greatly depends on the competition between reactive and advective-dispersive characteristic times. However, hydraulic properties of the aquifer are known to be spatially variable, which can lead to the formation of preferential flow channels and fast contamination pathways. Therefore, the uncertainty on the spatial distribution of the aquifer properties controlling the plume travel time may then play a particular role in the human health risk assessment of chemical mixtures. We investigate here the risk related to a multispecies system in response to different degrees of heterogeneity of the hydraulic conductivity (K or Y =ln(K)). This work focuses on a Perchloroethylene (PCE) contamination problem followed by the sequential first-order production/biodegradation of its daughter species Trichloroethylene (TCE), Dichloroethylene (DCE) and Vinyl Chlorine (VC). For this specific case, VC is known to be a highly toxic contaminant. By performing numerical experiments, we evaluate transport through three-dimensional mildly (σY 2=1.0) and highly (σY 2=4.0) heterogeneous aquifers. Uncertainty on the hydraulic

  3. A multimedia fate and chemical transport modeling system for pesticides: I. Model development and implementation

    Energy Technology Data Exchange (ETDEWEB)

    Li Rong; Yang Fuquan; Sloan, James J [Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Scholtz, M Trevor, E-mail: sloanj@connect.uwaterloo.ca [ORTECH Environmental, 2395 Speakman Drive, Mississauga, ON L5K 1B3 (Canada)

    2011-07-15

    We have combined the US EPA MM5/MCIP/SMOKE/CMAQ modeling system with a dynamic soil model, the pesticide emission model (PEM), to create a multimedia chemical transport model capable of describing the important physical and chemical processes involving pesticides in the soil, in the atmosphere, and on the surface of vegetation. These processes include: agricultural practices (e.g. soil tilling and pesticide application mode); advection and diffusion of pesticides, moisture, and heat in the soil; partitioning of pesticides between soil organic carbon and interstitial water and air; emissions from the soil to the atmosphere; gas-particle partitioning and transport in the atmosphere; and atmospheric chemistry and dry and wet deposition of pesticides to terrestrial and water surfaces. The modeling system was tested by simulating toxaphene in a domain that covers most of North America for the period from 1 January 2000 to 31 December 2000. The results show obvious transport of the pesticide from the heavily contaminated soils in the southern United States and Mexico to water bodies including the Atlantic Ocean, the Gulf of Mexico and the Great Lakes, leading to significant dry and wet deposition into these ecosystems. The spatial distributions of dry and wet depositions differ because of their different physical mechanisms; the former follows the distribution of air concentrations whereas the latter is more biased to the North East due to the effect of precipitation.

  4. A multimedia fate and chemical transport modeling system for pesticides: I. Model development and implementation

    Science.gov (United States)

    Li, Rong; Scholtz, M. Trevor; Yang, Fuquan; Sloan, James J.

    2011-07-01

    We have combined the US EPA MM5/MCIP/SMOKE/CMAQ modeling system with a dynamic soil model, the pesticide emission model (PEM), to create a multimedia chemical transport model capable of describing the important physical and chemical processes involving pesticides in the soil, in the atmosphere, and on the surface of vegetation. These processes include: agricultural practices (e.g. soil tilling and pesticide application mode); advection and diffusion of pesticides, moisture, and heat in the soil; partitioning of pesticides between soil organic carbon and interstitial water and air; emissions from the soil to the atmosphere; gas-particle partitioning and transport in the atmosphere; and atmospheric chemistry and dry and wet deposition of pesticides to terrestrial and water surfaces. The modeling system was tested by simulating toxaphene in a domain that covers most of North America for the period from 1 January 2000 to 31 December 2000. The results show obvious transport of the pesticide from the heavily contaminated soils in the southern United States and Mexico to water bodies including the Atlantic Ocean, the Gulf of Mexico and the Great Lakes, leading to significant dry and wet deposition into these ecosystems. The spatial distributions of dry and wet depositions differ because of their different physical mechanisms; the former follows the distribution of air concentrations whereas the latter is more biased to the North East due to the effect of precipitation.

  5. Semi-gas kinetics model for performance modeling of flowing chemical oxygen-iodine lasers (COIL)

    Institute of Scientific and Technical Information of China (English)

    GAO Zhi; HU Limin; SHEN Yiqing

    2004-01-01

    A semi-gas kinetics (SGK) model for performance analyses of flowing chemical oxygen-iodine laser (COIL) is presented. In this model, the oxygen-iodine reaction gas flow is treated as a continuous medium, and the effect of thermal motions of particles of different laser energy levels on the performances of the COIL is included and the velocity distribution function equations are solved by using the double-parameter perturbational method. For a premixed flow, effects of different chemical reaction systems, different gain saturation models and temperature, pressure, yield of excited oxygen, iodine concentration and frequency-shift on the performances of the COIL are computed, and the calculated output power agrees well with the experimental data. The results indicate that the power extraction of the SGK model considering 21 reactions is close to those when only the reversible pumping reaction is considered, while different gain saturation models and adjustable parameters greatly affect the output power, the optimal threshold gain range, and the length of power extraction.

  6. A standard telemental health evaluation model: the time is now.

    Science.gov (United States)

    Kramer, Greg M; Shore, Jay H; Mishkind, Matt C; Friedl, Karl E; Poropatich, Ronald K; Gahm, Gregory A

    2012-05-01

    The telehealth field has advanced historic promises to improve access, cost, and quality of care. However, the extent to which it is delivering on its promises is unclear as the scientific evidence needed to justify success is still emerging. Many have identified the need to advance the scientific knowledge base to better quantify success. One method for advancing that knowledge base is a standard telemental health evaluation model. Telemental health is defined here as the provision of mental health services using live, interactive video-teleconferencing technology. Evaluation in the telemental health field largely consists of descriptive and small pilot studies, is often defined by the individual goals of the specific programs, and is typically focused on only one outcome. The field should adopt new evaluation methods that consider the co-adaptive interaction between users (patients and providers), healthcare costs and savings, and the rapid evolution in communication technologies. Acceptance of a standard evaluation model will improve perceptions of telemental health as an established field, promote development of a sounder empirical base, promote interagency collaboration, and provide a framework for more multidisciplinary research that integrates measuring the impact of the technology and the overall healthcare aspect. We suggest that consideration of a standard model is timely given where telemental health is at in terms of its stage of scientific progress. We will broadly recommend some elements of what such a standard evaluation model might include for telemental health and suggest a way forward for adopting such a model.

  7. Assessing exposure and health consequences of chemicals in drinking water : Current state of knowledge and research needs

    NARCIS (Netherlands)

    Villanueva, Cristina M.; Kogevinas, Manolis; Cordier, Sylvaine; Templeton, Michael R.; Vermeulen, Roel; Nuckols, John R.; Nieuwenhuijsen, Mark J.; Levallois, Patrick

    2014-01-01

    Background: Safe drinking water is essential for well-being. Although microbiological contamination remains the largest cause of water-related morbidity and mortality globally, chemicals in water supplies may also cause disease, and evidence of the human health consequences is limited or lacking for

  8. Endocrine-Disrupting Activity of Hydraulic Fracturing Chemicals and Adverse Health Outcomes After Prenatal Exposure in Male Mice.

    Science.gov (United States)

    Kassotis, Christopher D; Klemp, Kara C; Vu, Danh C; Lin, Chung-Ho; Meng, Chun-Xia; Besch-Williford, Cynthia L; Pinatti, Lisa; Zoeller, R Thomas; Drobnis, Erma Z; Balise, Victoria D; Isiguzo, Chiamaka J; Williams, Michelle A; Tillitt, Donald E; Nagel, Susan C

    2015-12-01

    Oil and natural gas operations have been shown to contaminate surface and ground water with endocrine-disrupting chemicals. In the current study, we fill several gaps in our understanding of the potential environmental impacts related to this process. We measured the endocrine-disrupting activities of 24 chemicals used and/or produced by oil and gas operations for five nuclear receptors using a reporter gene assay in human endometrial cancer cells. We also quantified the concentration of 16 of these chemicals in oil and gas wastewater samples. Finally, we assessed reproductive and developmental outcomes in male C57BL/6J mice after the prenatal exposure to a mixture of these chemicals. We found that 23 commonly used oil and natural gas operation chemicals can activate or inhibit the estrogen, androgen, glucocorticoid, progesterone, and/or thyroid receptors, and mixtures of these chemicals can behave synergistically, additively, or antagonistically in vitro. Prenatal exposure to a mixture of 23 oil and gas operation chemicals at 3, 30, and 300 μg/kg · d caused decreased sperm counts and increased testes, body, heart, and thymus weights and increased serum testosterone in male mice, suggesting multiple organ system impacts. Our results suggest possible adverse developmental and reproductive health outcomes in humans and animals exposed to potential environmentally relevant levels of oil and gas operation chemicals.

  9. Some sensitivity studies of chemical transport simulated in models of the soil-plant-litter system

    Energy Technology Data Exchange (ETDEWEB)

    Begovich, C.L.; Luxmoore, R.J.

    1979-09-01

    Fifteen parameters in a set of five coupled models describing carbon, water, and chemical dynamics in the soil-plant-litter system were varied in a sensitivity analysis of model response. Results are presented for chemical distribution in the components of soil, plants, and litter along with selected responses of biomass, internal chemical transport (xylem and phloem pathways), and chemical uptake. Response and sensitivity coefficients are presented for up to 102 model outputs in an appendix. Two soil properties (chemical distribution coefficient and chemical solubility) and three plant properties (leaf chemical permeability, cuticle thickness, and root chemical conductivity) had the greatest influence on chemical transport in the soil-plant-litter system under the conditions examined. Pollutant gas uptake (SO/sub 2/) increased with change in plant properties that increased plant growth. Heavy metal dynamics in litter responded to plant properties (phloem resistance, respiration characteristics) which induced changes in the chemical cycling to the litter system. Some of the SO/sub 2/ and heavy metal responses were not expected but became apparent through the modeling analysis.

  10. Some Sensitivity Studies of Chemical Transport Simulated in Models of the Soil-Plant-Litter System

    Energy Technology Data Exchange (ETDEWEB)

    Begovich, C.L.

    2002-10-28

    Fifteen parameters in a set of five coupled models describing carbon, water, and chemical dynamics in the soil-plant-litter system were varied in a sensitivity analysis of model response. Results are presented for chemical distribution in the components of soil, plants, and litter along with selected responses of biomass, internal chemical transport (xylem and phloem pathways), and chemical uptake. Response and sensitivity coefficients are presented for up to 102 model outputs in an appendix. Two soil properties (chemical distribution coefficient and chemical solubility) and three plant properties (leaf chemical permeability, cuticle thickness, and root chemical conductivity) had the greatest influence on chemical transport in the soil-plant-litter system under the conditions examined. Pollutant gas uptake (SO{sub 2}) increased with change in plant properties that increased plant growth. Heavy metal dynamics in litter responded to plant properties (phloem resistance, respiration characteristics) which induced changes in the chemical cycling to the litter system. Some of the SO{sub 2} and heavy metal responses were not expected but became apparent through the modeling analysis.

  11. A review of models for near-field exposure pathways of chemicals in consumer products

    DEFF Research Database (Denmark)

    Huang, Lei; Ernstoff, Alexi; Fantke, Peter;

    2017-01-01

    Exposure to chemicals in consumer products has been gaining increasing attention, with multiple studies showing that near-field exposures from products is high compared to far-field exposures. Regarding the numerous chemical-product combinations, there is a need for an overarching review of models...... able to quantify the multiple transfers of chemicals from products used near-field to humans. The present review therefore aims at an in-depth overview of modeling approaches for near-field chemical release and human exposure pathways associated with consumer products. It focuses on lower...... in a “human receptor compartment”. We first focus on models of physical mass transfers from the product to ‘near-field’ compartments. For transfers of chemicals from article interior, adequate modeling of in-article diffusion and of partitioning between article surface and air/skin/food is key. Modeling...

  12. A model of health education and management for osteoporosis prevention

    OpenAIRE

    Wang, Liang; Xu, Xiaowen; Hao, Hongxia; Chen, Liying; Su, Tianjiao; Zhang, Yan; Ma, Weifeng; XIE, YUANYUAN; Wang, Tiantian; Yang, Fan; He, Li; Wang, Wenjiao; Fu, Xuemei; Ma, Yuanzheng

    2016-01-01

    Osteoporosis, a chronic disease with no therapeutic cure, affects a growing number of people as the aging population in China rapidly increases. Therefore, developing an evidence-based model of health education and management for osteoporosis prevention is required. In the present study, an osteoporosis club was established, which is a novel model of health education and management for osteoporosis prevention. A unified management of membership was used based on a digitized database. A total ...

  13. Sustaining librarian vitality: embedded librarianship model for health sciences libraries.

    Science.gov (United States)

    Wu, Lin; Mi, Misa

    2013-01-01

    With biomedical information widely accessible from anywhere at any time, health sciences libraries have become less centralized, and they are challenged to stay relevant and vital to the mission and strategic goals of their home institution. One solution is to embed librarians at strategic points in health professions' education, research, and patient care. This article discusses a proposed five-level model of embedded librarianship within the context of health sciences libraries and describes different roles, knowledge, and skills desirable for health sciences librarians working as embedded librarians.

  14. Latent variable modelling of personality-health associations: measures, models and extensions

    OpenAIRE

    Hagger-Johnson, Gareth

    2008-01-01

    Functional health status, morbidity and mortality are determined partly by health behaviours (World Health Organization, 2002), which have determinants of their own. Personality traits, such as Conscientiousness, have a strong association with health behaviours (Bogg & Roberts, 2004). There is a less consistent and generally weaker association between traits and health outcomes (e.g. Neuroticism and mortality). The central problem in this thesis is how to measure, model, max...

  15. Health Care Utilisation and Attitudes towards Health Care in Subjects Reporting Environmental Annoyance from Electricity and Chemicals

    Directory of Open Access Journals (Sweden)

    Frida Eek

    2009-01-01

    Full Text Available Environmentally intolerant persons report decreased self-rated health and daily functioning. However, it remains unclear whether this condition also results in increased health care costs. The aim of this study was to describe the health care consumption and attitudes towards health care in subjects presenting subjective environmental annoyance in relation to the general population, as well as to a group with a well-known disorder as treated hypertension (HT. Methods. Postal questionnaire (n = 13 604 and record linkage with population-based register on health care costs. Results. Despite significantly lower subjective well being and health than both the general population and HT group, the environmentally annoyed subjects had lower health care costs than the hypertension group. In contrast to the hypertension group, the environmentally annoyed subjects expressed more negative attitudes toward the health care than the general population. Conclusions. Despite their impaired subjective health and functional capacity, health care utilisation costs were not much increased for the environmentally annoyed group. This may partly depend on negative attitudes towards the health care in this group.

  16. Supporting frail seniors through a family physician and Home Health integrated care model in Fraser Health

    Directory of Open Access Journals (Sweden)

    Grace Haeson Park

    2014-03-01

    Full Text Available Background: A major effort is underway to integrate primary and community care in Canada's western province of British Columbia and in Fraser Health, its largest health authority. Integrated care is a critical component of Fraser Health's planning, to meet the challenges of caring for a growing, elderly population that is presenting more complex and chronic medical conditions. Description of integrated practice: An integrated care model partners family physicians with community-based home health case managers to support frail elderly patients who live at home. It is resulting in faster response times to patient needs, more informed assessments of a patient's state of health and pro-active identification of emerging patient issues. Early results: The model is intended to improve the quality of patient care and maintain the patients’ health status, to help them live at home confidently and safely, as long as possible. Preliminary pilot data measuring changes in home care services is showing positive trends when it comes to extending the length of a person's survival/tenure in the community (living in their home vs. admitted to residential care or deceased. Conclusion: Fraser Health's case manager–general practitioner partnership model is showing promising results including higher quality, appropriate, coordinated and efficient care; improved patient, caregiver and physician interactions with the system; improved health and prevention of acute care visits by senior adult patients.

  17. Supporting frail seniors through a family physician and Home Health integrated care model in Fraser Health

    Directory of Open Access Journals (Sweden)

    Grace Haeson Park

    2014-03-01

    Full Text Available Background: A major effort is underway to integrate primary and community care in Canada's western province of British Columbia and in Fraser Health, its largest health authority. Integrated care is a critical component of Fraser Health's planning, to meet the challenges of caring for a growing, elderly population that is presenting more complex and chronic medical conditions.Description of integrated practice: An integrated care model partners family physicians with community-based home health case managers to support frail elderly patients who live at home. It is resulting in faster response times to patient needs, more informed assessments of a patient's state of health and pro-active identification of emerging patient issues.Early results: The model is intended to improve the quality of patient care and maintain the patients’ health status, to help them live at home confidently and safely, as long as possible. Preliminary pilot data measuring changes in home care services is showing positive trends when it comes to extending the length of a person's survival/tenure in the community (living in their home vs. admitted to residential care or deceased.Conclusion: Fraser Health's case manager–general practitioner partnership model is showing promising results including higher quality, appropriate, coordinated and efficient care; improved patient, caregiver and physician interactions with the system; improved health and prevention of acute care visits by senior adult patients.

  18. Evidence for the credibility of health economic models for health policy decision-making

    DEFF Research Database (Denmark)

    Søgaard, Rikke; Lindholt, Jes S.

    2012-01-01

    extracted and the models were assessed for quality against guidelines for best practice by a multidisciplinary team. RESULTS: Seven models were identified and found to provide divergent guidance. Only three reports met 10 of the 15 quality criteria. CONCLUSIONS: Researchers in the field seem to have...... benefited from general advances in health economic modelling and some improvements in reporting were noted. However, the low level of agreement between studies in model structures and assumptions, and difficulty in justifying these (convergent validity), remain a threat to the credibility of health economic...

  19. Quantum origins of the Iczkowski-Margrave model of chemical potential

    Energy Technology Data Exchange (ETDEWEB)

    Valone, Steven M [Los Alamos National Laboratory

    2010-01-01

    Charge flow in materials is controlled at the atomistic level through some model of the chemical potential, such as the Iczkowski-Margrave (IM) model. This model is built largely on heuristic arguments. Here a model Hamiltonian is constructed at the atomistic level commensurate with the IM model. Essential properties of the model Hamiltonian are presented, including a possible revision of the charge dependence in the IM model. Transitional properties of the model are shown to be central to regulating charge flow.

  20. Postdeployment evaluation of health risk communication after exposure to a toxic industrial chemical.

    Science.gov (United States)

    Mancuso, James D; Ostafin, Margaret; Lovell, Mark

    2008-04-01

    Increasing emphasis is being placed on the appropriate communication of deployment-related risks among military service members. This report validates risk communication on the postdeployment health assessment (PDHA), in the context of a known, low-level exposure to a toxic industrial chemical. In late 2003, 245 soldiers were exposed to hexavalent chromium at an industrial site in Iraq; of those, 227 had completed PDHAs on file for review. Despite being directed to document this exposure upon redeployment, only 55 soldiers (24.2%) specifically reported chromium exposure. Increasing age and time at the industrial site were associated with increased reporting of exposure. Although providers documented deployment exposure concerns for only 65.4% of this population, this was much more often than for other redeploying service members. The PDHA is a risk assessment and risk communication tool that has sources of misclassification, and results must be interpreted with caution when individual or population occupational and environmental risks resulting from deployment are assessed.

  1. Bridging gaps in discovery and development: chemical and biological sciences for affordable health, wellness and sustainability.

    Science.gov (United States)

    Chauhan, Prem Man Singh

    2011-05-01

    To commemorate 2011 as the International Year of Chemistry, the Indian Society of Chemists and Biologists organized its 15th International Conference on 'Bridging Gaps in Discovery and Development: Chemical and Biological Sciences for Affordable Health, Wellness and Sustainability' at Hotel Grand Bhagwati, in association with Saurashtra University, Rajkot, India. Anamik Shah, President of the Indian Society of Chemists and Biologists, was organizing secretary of the conference. Nicole Moreau, President of the International Union of Pure and Applied Chemistry and Secretary General of the Comité National de la Chimie, National Centre for Scientific Research France, was chief guest of the function. The four-day scientific program included 52 plenary lectures, 24 invited lectures by eminent scientists in the field and 12 oral presentations. A total of 317 posters were presented by young scientists and PhD students in three different poster sessions. Approximately 750 delegates from India, the USA, UK, France, Switzerland, Germany, Austria, Belgium, Sweden, Japan and other countries attended the conference. The majority of the speakers gave presentations related to their current projects and areas of interest and many of the talks covered synthesis, structure-activity relationships, current trends in medicinal chemistry and drug research.

  2. Bio-antioxidants - a chemical base of their antioxidant activity and beneficial effect on human health.

    Science.gov (United States)

    Kancheva, V D; Kasaikina, O T

    2013-01-01

    The paradox of aerobic life is that higher eukaryotic organisms cannot exist without oxygen, yet oxygen is inherently dangerous to their existence. Autoxidation of organic substances frequently occurs via free radical mechanism which generates different active radicals and peroxides OH(•), O2 (•-), LO2 (•), HOOH, LOOH, so called reactive oxygen species (ROS), which appear to be responsible for oxygen toxicity. To survive in such an unfriendly oxygen environment, living organisms generate - or obtain from food - a variety of water- and lipid-soluble antioxidant compounds. Biologically active compounds with antioxidant potential, i.e. bio-antioxidants (natural and their synthetic analogues) have a wide range of applications. They are important drugs, antibiotics, agrochemical substitutes, and food preservatives. Many of the drugs today are synthetic modifications of naturally obtained substances. This review presents information about the chemical base of antioxidant activities and beneficial effects on human health of known and new bio-antioxidants. There is abundant literature on the phenolic antioxidants and tocopherols in particular. In this review the following bio-antioxidants are considered: A) Carotenoids, B) Cathecholamines, C) Phospholipids, D) Chalcones, E) Coumarins, F) Phenolic acids, G) Flavonoids, H) Lignans, and I) Tannins.

  3. Revitalising the evidence base for public health: an assets model.

    Science.gov (United States)

    Morgan, Antony; Ziglio, Erio

    2007-01-01

    Historically, approaches to the promotion of population health have been based on a deficit model. That is, they tend to focus on identifying the problems and needs of populations that require professional resources and high levels of dependence on hospital and welfare services. These deficit models are important and necessary to identify levels of needs and priorities. But they need to be complemented by some other perspectives as they have some drawbacks. Deficit models tend to define communities and individuals in negative terms, disregarding what is positive and works well in particular populations. In contrast 'assets' models tend to accentuate positive capability to identify problems and activate solutions. They focus on promoting salutogenic resources that promote the self esteem and coping abilities of individuals and communities, eventually leading to less dependency on professional services. Much of the evidence available to policy makers to inform decisions about the most effective approaches to promoting health and to tackling health inequities is based on a deficit model and this may disproportionately lead to policies and practices which disempower the populations and communities who are supposed to benefit from them. An assets approach to health and development embraces a 'salutogenic' notion of health creation and in doing so encourages the full participation of local communities in the health development process. The asset model presented here aims to revitalise how policy makers, researchers and practitioners think and act to promote a more resourceful approach to tackling health inequities. The model outlines a systematic approach to asset based public health which can provide scientific evidence and best practice on how to maximise the stock of key assets necessary for promoting health. Redressing the balance between the assets and deficit models for evidence based public health could help us to unlock some of the existing barriers to effective

  4. A generalized measurement model to quantify health: the multi-attribute preference response model.

    Directory of Open Access Journals (Sweden)

    Paul F M Krabbe

    Full Text Available After 40 years of deriving metric values for health status or health-related quality of life, the effective quantification of subjective health outcomes is still a challenge. Here, two of the best measurement tools, the discrete choice and the Rasch model, are combined to create a new model for deriving health values. First, existing techniques to value health states are briefly discussed followed by a reflection on the recent revival of interest in patients' experience with regard to their possible role in health measurement. Subsequently, three basic principles for valid health measurement are reviewed, namely unidimensionality, interval level, and invariance. In the main section, the basic operation of measurement is then discussed in the framework of probabilistic discrete choice analysis (random utility model and the psychometric Rasch model. It is then shown how combining the main features of these two models yields an integrated measurement model, called the multi-attribute preference response (MAPR model, which is introduced here. This new model transforms subjective individual rank data into a metric scale using responses from patients who have experienced certain health states. Its measurement mechanism largely prevents biases such as adaptation and coping. Several extensions of the MAPR model are presented. The MAPR model can be applied to a wide range of research problems. If extended with the self-selection of relevant health domains for the individual patient, this model will be more valid than existing valuation techniques.

  5. Improving Latino Youths' Environmental Health Literacy and Leadership Skills Through Participatory Research on Chemical Exposures in Cosmetics: The HERMOSA Study.

    Science.gov (United States)

    Madrigal, Daniel S; Minkler, Meredith; Parra, Kimberly L; Mundo, Carolina; Gonzalez, Jesus Enrique Cardenas; Jimenez, Ramon; Vera, Carlos; Harley, Kim G

    2016-07-18

    To increase environmental health literacy (EHL) and leadership skills in Latino youth in Salinas, CA., we worked from 2012-2015 with 15 members of the CHAMACOS Youth Community Council (YCC), an outreach arm of a longitudinal study of impacts of environmental chemicals on children's health. The YCC program provided hands-on research experiences related to Endocrine Disrupting Chemicals (EDCs) in cosmetics and their possible health effects. We use participatory research principles and Bloom's Taxonomy of Educational Objectives to describe the development of EHC and leadership in the youth co-researchers. Using data from multiple qualitative sources, we explore the youths' engagement in a wide range of research and action processes. Promising outcomes, including perceptions of improved youth self-esteem, EHL, leadership, and career orientation are discussed, as are challenges, such as time constraints and high priority youth concerns not addressed by the study. Implications for other youth-engaged participatory science and leadership programs are presented.

  6. Approaches to advancing quantitative human health risk assessment of environmental chemicals in the post-genomic era

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Weihsueh A., E-mail: chiu.weihsueh@epa.gov [National Center for Environmental Assessment, U.S. Environmental Protection Agency, Washington DC, 20460 (United States); Euling, Susan Y.; Scott, Cheryl Siegel; Subramaniam, Ravi P. [National Center for Environmental Assessment, U.S. Environmental Protection Agency, Washington DC, 20460 (United States)

    2013-09-15

    The contribution of genomics and associated technologies to human health risk assessment for environmental chemicals has focused largely on elucidating mechanisms of toxicity, as discussed in other articles in this issue. However, there is interest in moving beyond hazard characterization to making more direct impacts on quantitative risk assessment (QRA) — i.e., the determination of toxicity values for setting exposure standards and cleanup values. We propose that the evolution of QRA of environmental chemicals in the post-genomic era will involve three, somewhat overlapping phases in which different types of approaches begin to mature. The initial focus (in Phase I) has been and continues to be on “augmentation” of weight of evidence — using genomic and related technologies qualitatively to increase the confidence in and scientific basis of the results of QRA. Efforts aimed towards “integration” of these data with traditional animal-based approaches, in particular quantitative predictors, or surrogates, for the in vivo toxicity data to which they have been anchored are just beginning to be explored now (in Phase II). In parallel, there is a recognized need for “expansion” of the use of established biomarkers of susceptibility or risk of human diseases and disorders for QRA, particularly for addressing the issues of cumulative assessment and population risk. Ultimately (in Phase III), substantial further advances could be realized by the development of novel molecular and pathway-based biomarkers and statistical and in silico models that build on anticipated progress in understanding the pathways of human diseases and disorders. Such efforts would facilitate a gradual “reorientation” of QRA towards approaches that more directly link environmental exposures to human outcomes.

  7. A Model of Health for Family Caregivers of Elders

    Directory of Open Access Journals (Sweden)

    Florence M. Weierbach

    2016-12-01

    Full Text Available Family members who provide care to their loved ones experience changes in their own health. The caregiver health model (CGHM is a new model that identifies health holistically and identifies four determinant(s that contribute to the health status of the family caregiver. The purpose is to introduce the CGHM: Hypothesis 1: the determinants of health in the CGHM contribute to the health of the Caregiver, Hypothesis 2: the determinants of health contribute to changes in the caregivers’ health at 8 and 16 weeks, and Hypothesis 3: a change in health occurs from baseline to 8 and 16 weeks. Methods: A descriptive, longitudinal design used three data collection points and five survey instruments. Community recruitment (N = 90 occurred through word of mouth and newspapers. Inclusion criteria consisted of being a family caregiver, living in a rural residence, and providing care to elders with necessary activities of daily living (ADLs and/or instrumental ADLs (IADLs. Following a participant generated phone call to provide consent, caregivers received an initial study packet, additional packets were sent upon return of the previous packet. Analysis for the three hypotheses included multiple backwards stepwise linear regression, generalized estimating equations (GEE, and analysis of variance (ANOVA α = 0.05. Results: A significant decrease in mental (p < 0.01 but not physical health at 8 weeks (p = 0.38 and 16 weeks (p = 0.29 occurred over time. Two determinants displayed significant (p < 0.05 or less changes in mental and/or physical health at one or more time points. Study limitations include caregiver entry at varying times and self-report of elder nursing needs and medical conditions. Conclusions: Findings support two of the four determinants contributing to caregiver health.

  8. A detailed chemical kinetic model for pyrolysis of the lignin model compound chroman

    Directory of Open Access Journals (Sweden)

    James Bland

    2013-12-01

    Full Text Available The pyrolysis of woody biomass, including the lignin component, is emerging as a potential technology for the production of renewable fuels and commodity chemicals. Here we describe the construction and implementation of an elementary chemical kinetic model for pyrolysis of the lignin model compound chroman and its reaction intermediate ortho-quinone methide (o-QM. The model is developed using both experimental and theoretical data, and represents a hybrid approach to kinetic modeling that has the potential to provide molecular level insight into reaction pathways and intermediates while accurately describing reaction rates and product formation. The kinetic model developed here can replicate all known aspects of chroman pyrolysis, and provides new information on elementary reaction steps. Chroman pyrolysis is found to proceed via an initial retro-Diels–Alder reaction to form o-QM + ethene (C2H4, followed by dissociation of o-QM to the C6H6 isomers benzene and fulvene (+ CO. At temperatures of around 1000–1200 K and above fulvene rapidly isomerizes to benzene, where an activation energy of around 270 kJ mol-1 is required to reproduce experimental observations. A new G3SX level energy surface for the isomerization of fulvene to benzene supports this result. Our modeling also suggests that thermal decomposition of fulvene may be important at around 950 K and above. This study demonstrates that theoretical protocols can provide a significant contribution to the development of kinetic models for biomass pyrolysis by elucidating reaction mechanisms, intermediates, and products, and also by supplying realistic rate coefficients and thermochemical properties.

  9. Evaluation of QSAR models for predicting the partition coefficient (log P) of chemicals under the REACH regulation.

    Science.gov (United States)

    Cappelli, Claudia Ileana; Benfenati, Emilio; Cester, Josep

    2015-11-01

    The partition coefficient (log P) is a physicochemical parameter widely used in environmental and health sciences and is important in REACH and CLP regulations. In this regulatory context, the number of existing experimental data on log P is negligible compared to the number of chemicals for which it is necessary. There are many models to predict log P and we have selected a number of free programs to examine how they predict the log P of chemicals registered for REACH and to evaluate wheter they can be used in place of experimental data. Some results are good, especially if the information on the applicability domain of the models is considered, with R(2) values from 0.7 to 0.8 and root mean square error (RMSE) from 0.8 to 1.5.

  10. A model for training public health workers in health policy: the Nebraska Health Policy Academy.

    Science.gov (United States)

    Brandert, Kathleen; McCarthy, Claudine; Grimm, Brandon; Svoboda, Colleen; Palm, David; Stimpson, Jim P

    2014-05-15

    There is growing recognition that health goals are more likely to be achieved and sustained if programs are complemented by appropriate changes in the policies, systems, and environments that shape their communities. However, the knowledge, skills, and abilities needed to create and implement policy are among the major needs identified by practitioners at both the state and local levels. This article describes the structure and content of the Nebraska Health Policy Academy (the Academy), a 9-month program developed to meet the demand for this training. The Academy is a competency-based training program that aims to increase the capacity of Nebraska's state and local public health staff and their community partners to use public health policy and law as a public health tool. Our initiative allows for participation across a large, sparsely populated state; is grounded in adult learning theory; introduces the key principles and practices of policy, systems, and environmental change; and is offered free of charge to the state's public health workforce. Challenges and lessons learned when offering workforce development on public health policy efforts are discussed.

  11. 77 FR 76419 - Health and Safety Data Reporting; Addition of Certain Chemicals; Withdrawal of Final Rule

    Science.gov (United States)

    2012-12-28

    ... technical information contact: Mark Seltzer, Chemical Control Division (7405M), Office of Pollution...; telephone number: (202) 564-2901; email address: seltzer.mark@epa.gov or Mike Mattheisen, Chemical...

  12. Contemporary models of change in the health professions.

    Science.gov (United States)

    Schneller, E S; Ott, J B

    1996-01-01

    This article reviews the special position that health professionals have occupied and the ways in which changes threaten the foundations of professional work. The application of modern management principles to health care runs the risk of overriding the "action orientation" that is a defining component of professional work. One goal of health workforce design should be the engineering of opportunities for the preservation of "professional voice" as a countervailing force to ensure high quality health care. Contemporary models of change applied to health care workforce include: (1) the system of professions models in which securing and maintaining jurisdiction are the mechanisms that professions employ to sustain their position, (2) a strategic adaptation model by which professions attempt to adjust to changing environments, (3) a model of redesigning patient care which applies Total Quality Management (TQM) and other "industrial techniques" to the health care workplace, and, (4) model of "consumer sovereignty" in which groups of citizens come together to determine the nature of care services and professional work, with the participation of the organizations and providers.

  13. Social learning theory and the Health Belief Model.

    Science.gov (United States)

    Rosenstock, I M; Strecher, V J; Becker, M H

    1988-01-01

    The Health Belief Model, social learning theory (recently relabelled social cognitive theory), self-efficacy, and locus of control have all been applied with varying success to problems of explaining, predicting, and influencing behavior. Yet, there is conceptual confusion among researchers and practitioners about the interrelationships of these theories and variables. This article attempts to show how these explanatory factors may be related, and in so doing, posits a revised explanatory model which incorporates self-efficacy into the Health Belief Model. Specifically, self-efficacy is proposed as a separate independent variable along with the traditional health belief variables of perceived susceptibility, severity, benefits, and barriers. Incentive to behave (health motivation) is also a component of the model. Locus of control is not included explicitly because it is believed to be incorporated within other elements of the model. It is predicted that the new formulation will more fully account for health-related behavior than did earlier formulations, and will suggest more effective behavioral interventions than have hitherto been available to health educators.

  14. A discussion of regulatory requirements and air dispersion modeling approaches applicable to U.S. chemical demilitarization facilities.

    Science.gov (United States)

    Higgins, B W; Robbins, L B; Litynski, J

    1998-09-01

    Owners of hazardous waste treatment, storage, and disposal facilities, and certain major air pollution sources, must conduct several separate ambient air dispersion modeling analyses before beginning construction of new facilities or modifying existing facilities. These analyses are critical components of the environmental permitting and facility certification processes and must be completed to the satisfaction of federal, state, and local regulatory authorities. The U.S. Army has conducted air dispersion modeling for its proposed chemical agent disposal facilities to fulfill the following environmental regulatory and risk management requirements: (1) Resource Conservation and Recovery Act human health and ecological risk assessment analysis for the hazardous waste treatment and storage permit applications, (2) Quantitative Risk Assessment to support the site-specific risk management programs, and (3) Prevention of Significant Deterioration ambient air impact analysis for the air permit applications. The purpose of these air dispersion modeling studies is to show that the potential impacts on human health and the environment, due to operation of the chemical agent disposal facilities, are acceptable. This paper describes and compares the types of air dispersion models, modeling input data requirements, modeling algorithms, and approaches used to satisfy the three environmental regulatory and risk management requirements listed above. Although this paper discusses only one industry (i.e., chemical demilitarization), the information it contains could help those in other industries who need to communicate to the public the purpose and objectives of each modeling analysis. It may also be useful in integrating the results of each analysis into an overarching summary of compliance and potential risks.

  15. Population health improvement: a community health business model that engages partners in all sectors.

    Science.gov (United States)

    Kindig, David A; Isham, George

    2014-01-01

    Because population health improvement requires action on multiple determinants--including medical care, health behaviors, and the social and physical environments--no single entity can be held accountable for achieving improved outcomes. Medical organizations, government, schools, businesses, and community organizations all need to make substantial changes in how they approach health and how they allocate resources. To this end, we suggest the development of multisectoral community health business partnership models. Such collaborative efforts are needed by sectors and actors not accustomed to working together. Healthcare executives can play important leadership roles in fostering or supporting such partnerships in local and national arenas where they have influence. In this article, we develop the following components of this argument: defining a community health business model; defining population health and the Triple Aim concept; reaching beyond core mission to help create the model; discussing the shift for care delivery beyond healthcare organizations to other community sectors; examining who should lead in developing the community business model; discussing where the resources for a community business model might come from; identifying that better evidence is needed to inform where to make cost-effective investments; and proposing some next steps. The approach we have outlined is a departure from much current policy and management practice. But new models are needed as a road map to drive action--not just thinking--to address the enormous challenge of improving population health. While we applaud continuing calls to improve health and reduce disparities, progress will require more robust incentives, strategies, and action than have been in practice to date. Our hope is that ideas presented here will help to catalyze a collective, multisectoral response to this critical social and economic challenge.

  16. Developing a Semi-Quantitative Occupational Risk Prediction Model for Chemical Exposures and Its Application to a National Chemical Exposure Databank

    Directory of Open Access Journals (Sweden)

    Chiu-Ying Chen

    2013-07-01

    Full Text Available In this study, a semi-quantitative occupational chemical exposure risk prediction model, based on the calculation of exposure hazard indexes, was proposed, corrected, and applied to a national chemical exposure databank. The model comprises one factor used to describe toxicity (i.e., the toxicity index, and two factors used to reflect the exposure potential (i.e., the exposure index and protection deficiency index of workers exposed to chemicals. An expert system was used to correct the above proposed model. By applying the corrected model to data obtained from a national occupational chemical hazard survey program, chemical exposure risks of various manufacturing industries were determined and a national control strategy for the abatement of occupational chemical exposures was proposed. The results of the present study would provide useful information for governmental agencies to allocate their limited resources effectively for reducing chemical exposures of workers.

  17. Grouping chemicals for health risk assessment: A text mining-based case study of polychlorinated biphenyls (PCBs).

    Science.gov (United States)

    Ali, Imran; Guo, Yufan; Silins, Ilona; Högberg, Johan; Stenius, Ulla; Korhonen, Anna

    2016-01-22

    As many chemicals act as carcinogens, chemical health risk assessment is critically important. A notoriously time consuming process, risk assessment could be greatly supported by classifying chemicals with similar toxicological profiles so that they can be assessed in groups rather than individually. We have previously developed a text mining (TM)-based tool that can automatically identify the mode of action (MOA) of a carcinogen based on the scientific evidence in literature, and it can measure the MOA similarity between chemicals on the basis of their literature profiles (Korhonen et al., 2009, 2012). A new version of the tool (2.0) was recently released and here we apply this tool for the first time to investigate and identify meaningful groups of chemicals for risk assessment. We used published literature on polychlorinated biphenyls (PCBs)-persistent, widely spread toxic organic compounds comprising of 209 different congeners. Although chemically similar, these compounds are heterogeneous in terms of MOA. We show that our TM tool, when applied to 1648 PubMed abstracts, produces a MOA profile for a subgroup of dioxin-like PCBs (DL-PCBs) which differs clearly from that for the rest of PCBs. This suggests that the tool could be used to effectively identify homogenous groups of chemicals and, when integrated in real-life risk assessment, could help and significantly improve the efficiency of the process.

  18. MODELING DISPERSION FROM CHEMICALS RELEASED AFTER A TRAIN COLLISION IN GRANITEVILLE, SOUTH CAROLINA

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R; Chuck Hunter, C; Robert Addis, R; Matt Parker, M

    2006-08-07

    The Savannah River National Laboratory's (SRNL) Weather INformation and Display (WIND) System was used to provide meteorological and atmospheric modeling/consequence assessment support to state and local agencies following the collision of two Norfolk Southern freight trains on the morning of January 6, 2005. This collision resulted in the release of several toxic chemicals to the environment, including chlorine. The dense and highly toxic cloud of chlorine gas that formed in the vicinity of the accident was responsible for nine fatalities, and caused injuries to more than five hundred others. Transport model results depicting the forecast path of the ongoing release were made available to emergency managers in the county's Unified Command Center shortly after SRNL received a request for assistance. Support continued over the ensuing two days of the active response. The SRNL also provided weather briefings and transport/consequence assessment model results to responders from South Carolina Department of Health and Environmental Control (SCDHEC), the Savannah River Site's (SRS) Emergency Operations Center (EOC), Department of Energy Headquarters, and hazmat teams dispatched from the SRS. Although model-generated forecast winds used in consequence assessments conducted during the incident were provided at 2-km horizontal grid spacing during the accident response, a high-resolution Regional Atmospheric Modeling System (RAMS, version 4.3.0) simulation was later performed to examine potential influences of local topography on plume migration. The detailed RAMS simulation was used to determine meteorology using multiple grids with an innermost grid spacing of 125 meters. Results from the two simulations are shown to generally agree with meteorological observations at the time; consequently, local topography did not significantly affect wind in the area. Use of a dense gas dispersion model to simulate localized plume behavior using the higher resolution

  19. Business Models for Successfully Maintaining Games for Health.

    Science.gov (United States)

    Baranowski, Moderator Tom; Isaac, Participants Fikry; Ashford, Chris; Goldman, Ron; Lenihan, David J; Poole, Brent; Buday, Richard; van Rijswijk, Jurriaan

    2013-04-01

    Videogames for health provide innovative, exciting, and possibly highly effective new media for helping players change their behaviors or otherwise benefit their health. Getting the right videogames into the hands of players who can benefit most in a way that pays for the continued innovation and creation of such games is a current challenge. Entertainment videogame companies, which create games primarily to enhance players' enjoyment, have used the general business marketplace (e.g., online stores, walk-in stores, app stores) to deliver their products directly to consumers and earn enough capital to invest in making new products. No one believes, however, that enough kids or adults would use the general business marketplace to purchase games for health in sufficient volume to provide the down payment for the innovation and creation of new games for health. A successful business model is critical to the financial future of games for health. We asked members of our Editorial Board who are in health-related companies (Fikry Isaac, MD, MPH), in several game development companies (Chris Ashford, Ron Goldman, David J. Lenihan, Brent Poole, and Richard Buday, FAIA), and the head of the Games for Health Europe Foundation (Jurriaan van Rijswijk, MSc) to address questions in a roundtable about the current and possible future business models for games for health.

  20. Nutritional models for space travel from chemically defined diets

    Science.gov (United States)

    Dufour, P. A.

    1984-01-01

    Human nutritional requirements are summarized, including recommended daily intake and maximum safe chronic intake of nutrients. The biomedical literature on various types of chemically defined diets (CDD's), which are liquid, formulated diets for enteral and total parenteral nutrition, is reviewed. The chemical forms of the nutrients in CDD's are detailed, and the compositions and sources of representative commercial CDD's are tabulated. Reported effects of CDD's in medical patients, healthy volunteers, and laboratory animals are discussed. The effects include gastrointestinal side effects, metabolic imbalances, nutrient deficiencies and excesses, and psychological problems. Dietary factors contributing to the side effects are examined. Certain human nutrient requirements have been specified more precisely as a result of long-term use of CDD's, and related studies are included. CDD's are the most restricted yet nutritionally complete diets available.

  1. Models of chemical biosignatures - a vibrational spectroscopic study

    Science.gov (United States)

    Bödeker, B.; Böttger, U.; Hübers, H.-W.; deVera, J.-P.; Fox, S.; Strasdeit, H.

    2013-09-01

    Investigating possible biosignatures is of central interest in the search for the oldest traces of terrestrial life. Possible biosignatures are: (i) physical structures, such as fossilized single-celled or colonyforming microorganisms; (ii) biomolecules and their altered residues (chemical biosignatures); (iii) altered element, isotope and mineral compositions in former microbial habitats and related effects caused by metabolic activity [1]. New insights in this field of research are also important in the search for life on other planets and moons, especially Mars. However, abiotically formed organic compounds are widely distributed in the universe. Therefore, in future Mars missions, it will be essential to know whether organic molecules are actually of biological origin. Here, we describe the syntheses and spectroscopic (Raman and infrared) properties of artificial chemical biosignatures that might help answering this question.

  2. The role of mathematical modelling in chemical and food engineering studies

    OpenAIRE

    Brandão, Teresa R. S.; Silva, Cristina L. M.

    2003-01-01

    The role of mathematical modelling in chemical and food engineering studies is briefly and consistently presented. The main goal was to give a short global overview of the relevant aspects involved in modelling processes. Food engineering problems are generally highlighted. It must be emphasised that the following matter should not be analysed in a narrow perspective. The mathematical modelling field, in chemical and food engineering subjects, is very wide and this paper just presents the ...

  3. Extending Social Cognition Models of Health Behaviour

    Science.gov (United States)

    Abraham, Charles; Sheeran, Paschal; Henderson, Marion

    2011-01-01

    A cross-sectional study assessed the extent to which indices of social structure, including family socio-economic status (SES), social deprivation, gender and educational/lifestyle aspirations correlated with adolescent condom use and added to the predictive utility of a theory of planned behaviour model. Analyses of survey data from 824 sexually…

  4. Chemical Analysis of Whale Breath Volatiles: A Case Study for Non-Invasive Field Health Diagnostics of Marine Mammals

    Directory of Open Access Journals (Sweden)

    Raquel Cumeras

    2014-09-01

    Full Text Available We explored the feasibility of collecting exhaled breath from a moribund gray whale (Eschrichtius robustus for potential non-invasive health monitoring of marine mammals. Biogenic volatile organic compound (VOC profiling is a relatively new field of research, in which the chemical composition of breath is used to non-invasively assess the health and physiological processes on-going within an animal or human. In this study, two telescopic sampling poles were designed and tested with the primary aim of collecting whale breath exhalations (WBEs. Once the WBEs were successfully collected, they were immediately transferred onto a stable matrix sorbent through a custom manifold system. A total of two large volume WBEs were successfully captured and pre-concentrated onto two Tenax®-TA traps (one exhalation per trap. The samples were then returned to the laboratory where they were analyzed using solid phase micro extraction (SPME and gas chromatography/mass spectrometry (GC/MS. A total of 70 chemicals were identified (58 positively identified in the whale breath samples. These chemicals were also matched against a database of VOCs found in humans, and 44% of chemicals found in the whale breath are also released by healthy humans. The exhaled gray whale breath showed a rich diversity of chemicals, indicating the analysis of whale breath exhalations is a promising new field of research.

  5. Using the Health Belief Model for Bulimia Prevention.

    Science.gov (United States)

    Grodner, Michele

    1991-01-01

    Discusses application of the Health Belief Model to the prevention of bulimia, describing each model component. The article considers the individual's beliefs about bulimia and bulimic-like behaviors as a means of predicting the likelihood of behavior change to prevent clinically diagnosable bulimia. (SM)

  6. River Health Assessment Based on Fuzzy Matter-element Model

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The study aimed to assess the health state of rivers by using fuzzy matter-element model.[Method] Based on fuzzy matter-element analysis theory,the assessment model of river health was established,then a modified method to calculate the superior subordinate degree was put forward according to Hamming distance.Afterwards,a multi-level evaluation model,which contained the assessment indicators about hydrological features,ecological characteristics,environmental traits and service function,was set ...

  7. Health Impacts Estimation of Mineralogical and Chemical Characterization of Suspended Atmospheric Particles over the East Desert

    Directory of Open Access Journals (Sweden)

    U. A. Rahoma

    2010-01-01

    Full Text Available Problem statement: The small size fraction of aerosols, measured as PM10 and PM2.5, rather than the larger particles, is considered to be responsible for most of the health effects. Such particles have a relatively long residence time in the atmosphere and can therefore travel over long distances. Hence, a large portion of ambient concentrations of PM10 and in particular of particles with an aerodynamic diameter less than 2.5 µm (PM2.5, can be attributed to long range trans boundary air pollution or to other remote sources. The estimates of exposure and of health effects are based on a number of uncertain assumptions and data sets, as described in previous article. Approach: In industrialized Middle East countries, the daily deposition of PM10 particles in the lungs is roughly 250 µg day-1, which represents a small dose in terms of traditional toxicology studies. Studies of PM10 have considered this total material but have not asked how much its chemical or physical characteristics contribute to its total toxicity. Results: This article focuses on the description of the present knowledge on PM10 concentration fields and predominant sources contributing to PM10 from long range transport of pollution. PM10 is a complex mixture of many known and unknown components; therefore, a short introduction on the composition of PM10 is given. The studies denote to the African dust from mean PM10 levels background levels are still 5-10 mg m3 higher in the Eastern Basin (EMB when compared with those in the Western (WMB, mainly due to the higher anthropogenic and sea spray loads. Conclusion: As regards for the seasonal trends, these are largely driven by the occurrence of African dust events, resulting in a spring-early summer maximum over the EMB and a clear summer maximum in the WMB, although in this later region the recirculation of aged air masses play an important role. Furthermore, a marked seasonal trend is still evident when subtracting the African

  8. A Participatory Model for Multi-Document Health Information Summarisation

    Directory of Open Access Journals (Sweden)

    Dinithi Nallaperuma

    2017-03-01

    Full Text Available Increasing availability and access to health information has been a paradigm shift in healthcare provision as it empowers both patients and practitioners alike. Besides awareness, significant time savings and process efficiencies can be achieved through effective summarisation of healthcare information. Relevance and accuracy are key concerns when generating summaries for such documents. Despite advances in automated summarisation approaches, the role of participation has not been explored. In this paper, we propose a new model for multi-document health information summarisation that takes into account the role of participation. The updated IS user participation theory was extended to explicate these roles. The proposed model integrates both extractive and abstractive summarisation processes with continuous participatory inputs to each phase. The model was implemented as a client-server application and evaluated by both domain experts and health information consumers. Results from the evaluation phase indicates the model is successful in generating relevant and accurate summaries for diverse audiences.

  9. Sexual-Reproductive Health Belief Model of college students

    Directory of Open Access Journals (Sweden)

    Masoomeh Simbar

    2004-09-01

    Full Text Available Sexual- reproductive health of youth is one of the most unknown aspects of our community, while the world, including our country is faced with the risk of AIDS spreading. The aim of this study was to describe Health Belief Model (HBM of the students about sexual-reproductive health behaviors and evaluate the ability of the model in predicting related behaviors. By using quota sampling, 1117 male and female students of Qazvin Medical Science and International universities were included in the study in 1991. A self-completed questionnaire was prepared containing close questions based on HBM components including perceived threats (susceptibility and severity of related diseases, perceived reproductive benefits and barriers and self efficacy of youth about reproductive health. A total of 645 of participants were female and 457 were male (Mean age 21.4±2.4 and 22.7±3.5, respectively. The Health Belief Model of the students showed that they perceived a moderate threat for AIDS and venereal diseases and their health outcomes. Most of them perceived the benefits of reproductive health behaviors. They believed that the ability of youth in considering reproductive health is low or moderate. However, they noted to some barriers for spreading of reproductive health in youth including inadequacy of services. Boys felt a higher level of threat for acquiring the AIDS and venereal diseases in compare to girls, but girls had a higher knowledge about these diseases and their complications. The Health Belief Model of the students with premarital intercourse behavior was not significantly different with the students without this behavior (Mann-Withney, P<0.05. Female students and the students without the history of premarital intercourse had significantly more positive attitude towards abstinence, comparing to male students and students with the history of premarital intercourse, respectively (Mann-Withney, P<0.05. Seventy five percent of students believed in

  10. Effect of health belief model and health promotion model on breast cancer early diagnosis behavior: a systematic review.

    Science.gov (United States)

    Ersin, Fatma; Bahar, Zuhal

    2011-01-01

    Breast cancer is an important public health problem on the grounds that it is frequently seen and it is a fatal disease. The objective of this systematic analysis is to indicate the effects of interventions performed by nurses by using the Health Belief Model (HBM) and Health Promotion Model (HPM) on the breast cancer early diagnosis behaviors and on the components of the Health Belief Model and Health Promotion Model. The reveiw was created in line with the Centre for Reviews and Dissemination guide dated 2009 (CRD) and developed by York University National Institute of Health Researches. Review was conducted by using PUBMED, OVID, EBSCO and COCHRANE databases. Six hundred seventy eight studies (PUBMED: 236, OVID: 162, EBSCO: 175, COCHRANE:105) were found in total at the end of the review. Abstracts and full texts of these six hundred seventy eight studies were evaluated in terms of inclusion and exclusion criteria and 9 studies were determined to meet the criteria. Samplings of the studies varied between ninety four and one thousand six hundred fifty five. It was detected in the studies that educations provided by taking the theories as basis became effective on the breast cancer early diagnosis behaviors. When the literature is examined, it is observed that the experimental researches which compare the concepts of Health Belief Model (HBM) and Health Promotion Model (HPM) preoperatively and postoperatively and show the effect of these concepts on education and are conducted by nurses are limited in number. Randomized controlled studies which compare HBM and HPM concepts preoperatively and postoperatively and show the efficiency of the interventions can be useful in evaluating the efficiency of the interventions.

  11. The Application of the Health Belief Model in Oral Health Education

    Directory of Open Access Journals (Sweden)

    M Solhi

    2010-12-01

    Full Text Available "nBackground: The goal of this study was to determine the application of health belief model in oral health education for 12-year-old children and its effect on oral health behaviors and indexes. "nMethods: A quasi- experimental study was carried out on twelve-year-old girl students (n-291 in the first grade of secon­dary school, in the central district of Tehran, Iran. Research sample was selected by a multistage cluster sampling. The data was obtained by using a valid reliable questionnaire for measuring the perceptions, a checklist for observing the quality of brush­ing and dental flossing and health files and clinical observation. First, a descriptive study was applied to individual percep­tions, oral behaviors, Oral Hygiene Index (OHI and Decayed, Missing and Filled Teeth Index (DMFTI. Then an educa­tional planning based on the results and Health Belief Model (HBM was applied. The procedure was repeated after six months. "nResults: After education, based on HBM, all the oral health perceptions increased (P<.05. Correct brushing and flossing are influenced by increased perceptions. A low correlation between the reduction of DMFTI and increased perceived sever­ity and increased perceived barriers are found (r= -0.28, r = 0.43 respectively. In addition, there was a limited correlation be­tween OHI and increased perceived benefits (r = -0.26. "nConclusion: Using health belief model in oral health education for increasing the likelihood of taking preventive oral health be­haviors is applicable.  

  12. Consideration of an applied model of public health program infrastructure.

    Science.gov (United States)

    Lavinghouze, René; Snyder, Kimberly; Rieker, Patricia; Ottoson, Judith

    2013-01-01

    Systemic infrastructure is key to public health achievements. Individual public health program infrastructure feeds into this larger system. Although program infrastructure is rarely defined, it needs to be operationalized for effective implementation and evaluation. The Ecological Model of Infrastructure (EMI) is one approach to defining program infrastructure. The EMI consists of 5 core (Leadership, Partnerships, State Plans, Engaged Data, and Managed Resources) and 2 supporting (Strategic Understanding and Tactical Action) elements that are enveloped in a program's context. We conducted a literature search across public health programs to determine support for the EMI. Four of the core elements were consistently addressed, and the other EMI elements were intermittently addressed. The EMI provides an initial and partial model for understanding program infrastructure, but additional work is needed to identify evidence-based indicators of infrastructure elements that can be used to measure success and link infrastructure to public health outcomes, capacity, and sustainability.

  13. A probabilistic model for secondary structure prediction from protein chemical shifts.

    Science.gov (United States)

    Mechelke, Martin; Habeck, Michael

    2013-06-01

    Protein chemical shifts encode detailed structural information that is difficult and computationally costly to describe at a fundamental level. Statistical and machine learning approaches have been used to infer correlations between chemical shifts and secondary structure from experimental chemical shifts. These methods range from simple statistics such as the chemical shift index to complex methods using neural networks. Notwithstanding their higher accuracy, more complex approaches tend to obscure the relationship between secondary structure and chemical shift and often involve many parameters that need to be trained. We present hidden Markov models (HMMs) with Gaussian emission probabilities to model the dependence between protein chemical shifts and secondary structure. The continuous emission probabilities are modeled as conditional probabilities for a given amino acid and secondary structure type. Using these distributions as outputs of first- and second-order HMMs, we achieve a prediction accuracy of 82.3%, which is competitive with existing methods for predicting secondary structure from protein chemical shifts. Incorporation of sequence-based secondary structure prediction into our HMM improves the prediction accuracy to 84.0%. Our findings suggest that an HMM with correlated Gaussian distributions conditioned on the secondary structure provides an adequate generative model of chemical shifts.

  14. High-throughput exposure modeling to support prioritization of chemicals in personal care products

    DEFF Research Database (Denmark)

    Csiszar, Susan A.; Ernstoff, Alexi; Fantke, Peter

    2016-01-01

    We demonstrate the application of a high-throughput modeling framework to estimate exposure to chemicals used in personal care products (PCPs). As a basis for estimating exposure, we use the product intake fraction (PiF), defined as the mass of chemical taken by an individual or population per mass...

  15. A Conceptual Framework for Predicting the Toxicity of Reactive Chemicals: Modeling Soft Electrophilicity

    Science.gov (United States)

    Although the literature is replete with QSAR models developed for many toxic effects caused by reversible chemical interactions, the development of QSARs for the toxic effects of reactive chemicals lacks a consistent approach. While limitations exit, an appropriate starting-point...

  16. Numerical modeling of chemical spills and assessment of their environmental impacts

    Science.gov (United States)

    Chemical spills in surface water bodies often occur in modern societies, which cause significant impacts on water quality, eco-environment and drinking water safety. In this paper, chemical spill contamination in water resources was studied using a depth-integrated computational model, CCHE2D, for p...

  17. Analyzing Sexual Health-Related Beliefs Among Couples in Marriage Based on the Health Belief Model

    Directory of Open Access Journals (Sweden)

    Majid Barati

    2014-06-01

    Full Text Available Introduction: Sexual health is the integrity between mind, emotions, and body, and any disorder leading to discoordination, can be associated with sexual dysfunction. The aim of this study was to investigate the beliefs of couples attending marriage counseling centers toward sexual health based on the health belief model. Materials and Methods: This cross sectional descriptive study was performed on 400 couples referring to marriage counseling centers of Hamadan recruited with a random sampling method. The participants completed a self-administered questionnaire including demographic characteristics, knowledge and health belief model constructs. Data analysis was performed using SPSS-16 software, by Pearson’s coefficient correlation, independent T-test, and one-way ANOVA. Results: Couples had a moderate knowledge of sexual health. In addition, perceived susceptibility and severity of the consequences of unsafe sexual behavior among couples were not satisfactory however, perceived benefits and barriers were reported in a relatively good level. Internet and friends were the most important sources for sexual health information. Conclusion: Promoting knowledge and beliefs toward sexual health by preparing training packages based on the needs of couples and removing obstacles to have normal sexual behavior are necessary.

  18. Potential chemical and microbiological risks on human health from urban wastewater reuse in agriculture. Case study of wastewater effluents in Spain.

    Science.gov (United States)

    Muñoz, Ivan; Tomàs, Núria; Mas, Jordi; García-Reyes, Juan Fracisco; Molina-Díaz, Antonio; Fernández-Alba, Amadeo R

    2010-05-01

    Potential health risks derived from wastewater reuse in agriculture have been evaluated with Risk Assessment modelling techniques, in a case study involving the effluents of two Spanish wastewater treatment plants. One of the plants applies primary and secondary treatment, and the other one applies an additional tertiary treatment. Health risks were assessed on the basis of ingesting contaminated food, due to exposure to: (i) 22 chemical pollutants, namely pharmaceuticals and personal care products (PPCPs), and priority pollutants included in the European Framework Directive, and (ii) microorganisms, namely enterovirus. Chemical Risk Assessment has been carried out following the European Commission's technical guidelines, while risks from exposure to viruses have been evaluated by means of Quantitative Microbial Risk Assessment, assuming a virus to coliform ratio of 1:10(5). The results of the chemical assessment show that there is a margin of safety above 100 for all substances, with the exception of gemfibrozil, for which the mean margin of safety (MOS) is above 100, but the lower bound of MOS with a 95 % confidence interval lies in the 3-4 range. A MOS under 100 was also found for 2,3,7,8-TCDD in one of the effluents. The assessment of risks from viruses shows a very low probability of infection. The overall results show that risks are lower for the plant applying tertiary treatment, especially concerning microbiological parameters.

  19. CHILDREN'S MENTAL HEALTH SERVICE USE AND MATERNAL MENTAL HEALTH: A PATH ANALYTIC MODEL.

    Science.gov (United States)

    Pfefferle, Susan G; Spitznagel, Edward L

    2009-03-01

    OBJECTIVE: This observational study explores pathways towards any past year use of child mental health services. METHODS: Data from the 2002 National Survey of American Families were used to explore the relationship between past month maternal mental health and past year child mental health services use. Observations were limited to the 8072 most knowledgeable adults who were the mothers of target children aged 6-11. Logistic regressions were performed to determine the odds of any child mental health service use followed by path analyses using Maximum Likelihood estimation with robust standard errors. RESULTS: Multiple factors were associated with odds of any child mental health service use. In the path analytic model poor past month maternal mental health was associated with increased aggravation which in turn was associated with increased use of mental health visits. Negative child behaviors as reported by the mother were also associated with increased maternal aggravation and increased service use. CONCLUSIONS: Parental perception of child behaviors influences treatment seeking, both directly and indirectly through parental aggravation. Parental mental health influences tolerance for child behaviors. Findings are consistent with other studies. Interventions should address the entire family and their psychosocial circumstances through collaboration between multiple service sectors.

  20. Theoretical Modeling of 99 Tc NMR Chemical Shifts

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Gabriel B.; Andersen, Amity; Washton, Nancy M.; Chatterjee, Sayandev; Levitskaia, Tatiana G.

    2016-09-06

    Technetium (Tc) displays a rich chemistry due to the wide range of oxidation states (from -I to +VII) and ability to form coordination compounds. Determination of Tc speciation in complex mixtures is a major challenge, and 99Tc NMR spec-troscopy is widely used to probe chemical environments of Tc in odd oxidation states. However interpretation of the 99Tc NMR data is hindered by the lack of reference compounds. DFT computations can help fill this gap, but to date few com-putational studies have focused on 99Tc NMR of compounds and complexes. This work systematically evaluates the inclu-sion small percentages of Hartree-Fock exchange correlation and relativistic effects in DFT computations to support in-terpretation of the 99Tc NMR spectra. Hybrid functionals are found to perform better than their pure GGA counterparts, and non-relativistic calculations have been found to generally show a lower mean absolute deviation from experiment. Overall non-relativistic PBE0 and B3PW91 calculations are found to most accurately predict 99Tc NMR chemical shifts.

  1. Smart health monitoring systems: an overview of design and modeling.

    Science.gov (United States)

    Baig, Mirza Mansoor; Gholamhosseini, Hamid

    2013-04-01

    Health monitoring systems have rapidly evolved during the past two decades and have the potential to change the way health care is currently delivered. Although smart health monitoring systems automate patient monitoring tasks and, thereby improve the patient workflow management, their efficiency in clinical settings is still debatable. This paper presents a review of smart health monitoring systems and an overview of their design and modeling. Furthermore, a critical analysis of the efficiency, clinical acceptability, strategies and recommendations on improving current health monitoring systems will be presented. The main aim is to review current state of the art monitoring systems and to perform extensive and an in-depth analysis of the findings in the area of smart health monitoring systems. In order to achieve this, over fifty different monitoring systems have been selected, categorized, classified and compared. Finally, major advances in the system design level have been discussed, current issues facing health care providers, as well as the potential challenges to health monitoring field will be identified and compared to other similar systems.

  2. How Iranian women conceptualize mental health: an explanatory model.

    Directory of Open Access Journals (Sweden)

    Arash Mirabzadeh

    2014-03-01

    Full Text Available In Iran, more than 25% of women suffer from mental disorders. Mental disorders and subclinical problems are associated with socioeconomic problem. At the community level, mental health promotion can reduce social damage. The aim of this study as a part of community based mental health promotion intervention was to explore how mental health in Iranian women is viewed.According to a qualitative method in 2012, participants were selected by purposeful sampling from married women 18 to 65 years who are residents in Tehran. Fifteen in depth individual interviews were conducted with regard to the concept of mental health, causal pathway and help-seeking behavior according to explanatory model.Mental health was perceived as the same of emotional well-being. It conceptualized not only lack of mental disorder but also sense of satisfaction and healthy functioning. According to participant's view, the causal pathway of mental health problems were classified to individual, familial and social factors. Physical and behavioral problems were related to individual factor, Lack of marital adjustment was one of the most important issues in familial item and in social factor, cultural context and socio-economic problems were extracted. In help seeking process, all of the participants believed that the religion has important effect in mental health.Marital adjustment is an important stage in process of mental health in women.

  3. Evaluation of the Component Chemical Potentials in Analytical Models for Ordered Alloy Phases

    Directory of Open Access Journals (Sweden)

    W. A. Oates

    2011-01-01

    Full Text Available The component chemical potentials in models of solution phases with a fixed number of sites can be evaluated easily when the Helmholtz energy is known as an analytical function of composition. In the case of ordered phases, however, the situation is less straightforward, because the Helmholtz energy is a functional involving internal order parameters. Because of this, the chemical potentials are usually obtained numerically from the calculated integral Helmholtz energy. In this paper, we show how the component chemical potentials can be obtained analytically in ordered phases via the use of virtual cluster chemical potentials. Some examples are given which illustrate the simplicity of the method.

  4. High-throughput exposure modeling to support prioritization of chemicals in personal care products

    DEFF Research Database (Denmark)

    Csiszar, Susan A.; Ernstoff, Alexi; Fantke, Peter;

    2016-01-01

    We demonstrate the application of a high-throughput modeling framework to estimate exposure to chemicals used in personal care products (PCPs). As a basis for estimating exposure, we use the product intake fraction (PiF), defined as the mass of chemical taken by an individual or population per mass...... intakes were associated with body lotion. Bioactive doses derived from high-throughput in vitro toxicity data were combined with the estimated PiFs to demonstrate an approach to estimate bioactive equivalent chemical content and to screen chemicals for risk....

  5. Simulation and visualization of coupled hydrodynamical, chemical and biological models

    Directory of Open Access Journals (Sweden)

    Dag Slagstad

    1997-04-01

    Full Text Available This paper briefly describes the principles of hydrodynamical and ecological modelling of marine systems and how model results are presented by use of MATLAB. Two application examples are shown. One refers to modelling and simulation of the carbon vertical transport in the Greenland Sea and the other is a study on the effect of wind pattern for the invasion success of zooplankton from the Norwegian Sea into the North Sea by use of particle tracking.

  6. Modelling biological and chemically induced precipitation of calcium phosphate in enhanced biological phosphorus removal systems.

    Science.gov (United States)

    Barat, R; Montoya, T; Seco, A; Ferrer, J

    2011-06-01

    The biologically induced precipitation processes can be important in wastewater treatment, in particular treating raw wastewater with high calcium concentration combined with Enhanced Biological Phosphorus Removal. Currently, there is little information and experience in modelling jointly biological and chemical processes. This paper presents a calcium phosphate precipitation model and its inclusion in the Activated Sludge Model No 2d (ASM2d). The proposed precipitation model considers that aqueous phase reactions quickly achieve the chemical equilibrium and that aqueous-solid change is kinetically governed. The model was calibrated using data from four experiments in a Sequencing Batch Reactor (SBR) operated for EBPR and finally validated with two experiments. The precipitation model proposed was able to reproduce the dynamics of amorphous calcium phosphate (ACP) formation and later crystallization to hydroxyapatite (HAP) under different scenarios. The model successfully characterised the EBPR performance of the SBR, including the biological, physical and chemical processes.

  7. Budget of tropospheric ozone during TOPSE from two chemical transport models

    Science.gov (United States)

    Emmons, L. K.; Hess, P.; Klonecki, A.; Tie, X.; Horowitz, L.; Lamarque, J.-F.; Kinnison, D.; Brasseur, G.; Atlas, E.; Browell, E.; Cantrell, C.; Eisele, F.; Mauldin, R. L.; Merrill, J.; Ridley, B.; Shetter, R.

    2003-04-01

    The tropospheric ozone budget during the Tropospheric Ozone Production about the Spring Equinox (TOPSE) campaign has been studied using two chemical transport models (CTMs): HANK and the Model of Ozone and Related chemical Tracers, version 2 (MOZART-2). The two models have similar chemical schemes but use different meteorological fields, with HANK using MM5 (Pennsylvania State University, National Center for Atmospheric Research Mesoscale Modeling System) and MOZART-2 driven by European Centre for Medium-Range Weather Forecasts (ECMWF) fields. Both models simulate ozone in good agreement with the observations but underestimate NOx. The models indicate that in the troposphere, averaged over the northern middle and high latitudes, chemical production of ozone drives the increase of ozone seen in the spring. Both ozone gross chemical production and loss increase greatly over the spring months. The in situ production is much larger than the net stratospheric input, and the deposition and horizontal fluxes are relatively small in comparison to chemical destruction. The net production depends sensitively on the concentrations of H2O, HO2 and NO, which differ slightly in the two models. Both models underestimate the chemical production calculated in a steady state model using TOPSE measurements, but the chemical loss rates agree well. Measures of the stratospheric influence on tropospheric ozone in relation to in situ ozone production are discussed. Two different estimates of the stratospheric fraction of O3 in the Northern Hemisphere troposphere indicate it decreases from 30-50% in February to 15-30% in June. A sensitivity study of the effect of a perturbation in the vertical flux on tropospheric ozone indicates the contribution from the stratosphere is approximately 15%.

  8. 77 FR 71561 - Health and Safety Data Reporting; Addition of Certain Chemicals

    Science.gov (United States)

    2012-12-03

    ... organic dyes and pigments, gum and wood chemicals, cyclic crudes and intermediates, and ethyl alcohol... recordkeeping requirements. Dated: November 20, 2012. Wendy C. Hamnett, Director, Office of Pollution...

  9. A mathematical model and simulation results of plasma enhanced chemical vapor deposition of silicon nitride films

    Science.gov (United States)

    Konakov, S. A.; Krzhizhanovskaya, V. V.

    2015-01-01

    We developed a mathematical model of Plasma Enhanced Chemical Vapor Deposition (PECVD) of silicon nitride thin films from SiH4-NH3-N2-Ar mixture, an important application in modern materials science. Our multiphysics model describes gas dynamics, chemical physics, plasma physics and electrodynamics. The PECVD technology is inherently multiscale, from macroscale processes in the chemical reactor to atomic-scale surface chemistry. Our macroscale model is based on Navier-Stokes equations for a transient laminar flow of a compressible chemically reacting gas mixture, together with the mass transfer and energy balance equations, Poisson equation for electric potential, electrons and ions balance equations. The chemical kinetics model includes 24 species and 58 reactions: 37 in the gas phase and 21 on the surface. A deposition model consists of three stages: adsorption to the surface, diffusion along the surface and embedding of products into the substrate. A new model has been validated on experimental results obtained with the "Plasmalab System 100" reactor. We present the mathematical model and simulation results investigating the influence of flow rate and source gas proportion on silicon nitride film growth rate and chemical composition.

  10. Organizational models of emerging academic health science centers in England.

    Science.gov (United States)

    Ovseiko, Pavel V; Davies, Stephen M; Buchan, Alastair M

    2010-08-01

    Recent government policy initiatives to foster medical innovation and high-quality care in England have prompted academic and clinical leaders to develop new organizational models to support the tripartite Flexnerian mission of academic medicine. Medical schools and health care providers have responded by aligning their missions and creating integrated governance structures that strengthen their partnerships. In March 2009, the government officially designated five academic-clinical partnerships as England's first academic health science centers (AHSCs). As academic-clinical integration is likely to continue, future AHSC leaders could benefit from an analysis of models for organizing medical school-clinical enterprise relationships in England's emerging AHSCs. In addition, as the United States ponders health systems reform and universal coverage, U.S. medical leaders may benefit from insight into the workings of academic medicine in England's universal health system. In this article, the authors briefly characterize the organization and financing of the National Health Service and how it supports academic medicine. They review the policy behind the designation of AHSCs. Then, the authors describe contrasting organizational models adopted in two of the newly designated AHSCs and analyze these models using a framework derived from U.S. literature. The authors conclude by outlining the major challenges facing academic medicine in England and offer suggestions for future research collaborations between leaders of AHSCs in the United States and England.

  11. A Chemically Relevant Model for Teaching the Second Law of Thermodynamics.

    Science.gov (United States)

    Williamson, Bryce E.; Morikawa, Tetsuo

    2002-01-01

    Introduces a chemical model illustrating the aspects of the second law of thermodynamics which explains concepts such as reversibility, path dependence, and extrapolation in terms of electrochemistry and calorimetry. Presents a thought experiment using an ideal galvanic electrochemical cell. (YDS)

  12. A Hierarchical Model Architecture for Enterprise Integration in Chemical Industries

    Institute of Scientific and Technical Information of China (English)

    华贲; 周章玉; 成思危

    2001-01-01

    Towards integration of supply chain, manufacturing/production and investment decision making, this paper presents a hierarchical model architecture which contains six sub-models covering the areas of manufacturing control, production operation, design and revamp, production management, supply chain and investment decision making. Six types of flow, material, energy, information, humanware, partsware and capital are ciasified. These flows connect enterprise components/subsystems to formulate system topology and logical structure. Enterprise components/subsystems are abstracted to generic elementary and composite classes. Finally, the model architecture is applied to a management system of an integrated suply chain, and suggestion are made on the usage of the model architecture and further development of the model as well as imvlementation issues.

  13. Piecewise linear and Boolean models of chemical reaction networks.

    Science.gov (United States)

    Veliz-Cuba, Alan; Kumar, Ajit; Josić, Krešimir

    2014-12-01

    Models of biochemical networks are frequently complex and high-dimensional. Reduction methods that preserve important dynamical properties are therefore essential for their study. Interactions in biochemical networks are frequently modeled using Hill functions ([Formula: see text]). Reduced ODEs and Boolean approximations of such model networks have been studied extensively when the exponent [Formula: see text] is large. However, while the case of small constant [Formula: see text] appears in practice, it is not well understood. We provide a mathematical analysis of this limit and show that a reduction to a set of piecewise linear ODEs and Boolean networks can be mathematically justified. The piecewise linear systems have closed-form solutions that closely track those of the fully nonlinear model. The simpler, Boolean network can be used to study the qualitative behavior of the original system. We justify the reduction using geometric singular perturbation theory and compact convergence, and illustrate the results in network models of a toggle switch and an oscillator.

  14. Piecewise linear and Boolean models of chemical reaction networks

    Science.gov (United States)

    Veliz-Cuba, Alan; Kumar, Ajit; Josić, Krešimir

    2014-01-01

    Models of biochemical networks are frequently complex and high-dimensional. Reduction methods that preserve important dynamical properties are therefore essential for their study. Interactions in biochemical networks are frequently modeled using Hill functions (xn/(Jn + xn)). Reduced ODEs and Boolean approximations of such model networks have been studied extensively when the exponent n is large. However, while the case of small constant J appears in practice, it is not well understood. We provide a mathematical analysis of this limit, and show that a reduction to a set of piecewise linear ODEs and Boolean networks can be mathematically justified. The piecewise linear systems have closed form solutions that closely track those of the fully nonlinear model. The simpler, Boolean network can be used to study the qualitative behavior of the original system. We justify the reduction using geometric singular perturbation theory and compact convergence, and illustrate the results in network models of a toggle switch and an oscillator. PMID:25412739

  15. Oral health in Brazil: the challenges for dental health care models.

    Science.gov (United States)

    Chaves, Sônia Cristina Lima

    2012-01-01

    This paper discusses adult oral health in Brazil according to three perspectives: 1) the available epidemiological evidence about the population's oral-health-related epidemiological situation, especially adults and the elderly population, in relation to two high prevalence oral injuries (dental caries and tooth loss), 2) the main health care models for dealing with this situation, by analyzing the related historical processes in order to reveal the likely social, political and epidemiological implications of the different models, and 3) lastly, the possible challenges to Brazilian dentistry or collective oral health in overcoming these obstacles. The main results of the study indicate that, from an epidemiological point of view, Brazil is undergoing a transition in dental caries and tooth loss, which is not yet reflected in the profile of the elderly, but which is tentatively evidenced in young adults. Tooth loss remains high. Certain aspects of society's economic and political superstructure have an important impact on oral health indicators and existing inequalities. Oral health care models have a relative importance and must not be neglected. Vestiges of ideological movements, like preventive medicine, may explain the current impasse in collective oral health practices, such as the preeminence of Finalized Treatment (FT) in clinics and of preventive care in schools fostered by community-based programs. It is therefore important to develop conceptual, theoretical reflections and to increase the objects of intervention, their purposes and their modus operandi. The practice of dentistry according to these alternative models is still being constructed. New studies related to the different formats of these new practices are recommended.

  16. Chemical kinetic modeling of H{sub 2} applications

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C.K.; Marinov, N.; Pitz, W.J.; Curran, H. [Lawrence Livermore National Lab., CA (United States)

    1996-10-01

    This project is intended to develop detailed and simplified kinetic reaction mechanisms for the combustion of practical systems fueled by hydrogen, and then to use those mechanisms to examine the performance, efficiency, pollutant emissions, and other characteristics of those systems. During the last year, a H2/NOx mechanism has been developed that gives much improved predictions of NOx emissions compared to experimental data. Preliminary chemical kinetic and equilibrium calculations have been performed in support of Br2-H2O experiments to be conducted at NREL. Hydrogen, hydrogen/methane and hydrogen/natural gas mixtures have been investigated in a knock-rating engine to assess their automotive knock characteristics. The authors are currently developing the simplified analog reaction mechanisms that are computationally simple, yet still reproduce many of the macroscopic features of flame propagation.

  17. Modeling contact angle hysteresis on chemically patterned and superhydrophobic surfaces.

    Science.gov (United States)

    Kusumaatmaja, H; Yeomans, J M

    2007-05-22

    We investigate contact angle hysteresis on chemically patterned and superhydrophobic surfaces, as the drop volume is quasistatically increased and decreased. We consider both two (cylindrical drops) and three (spherical drops) dimensions using analytical and numerical approaches to minimize the free energy of the drop. In two dimensions, we find, in agreement with other authors, a slip, jump, stick motion of the contact line. In three dimensions, this behavior persists, but the position and magnitude of the contact line jumps are sensitive to the details of the surface patterning. In two dimensions, we identify analytically the advancing and receding contact angles on the different surfaces, and we use numerical insights to argue that these provide bounds for the three-dimensional cases. We present explicit simulations to show that a simple average over the disorder is not sufficient to predict the details of the contact angle hysteresis and to support an explanation for the low contact angle hysteresis of suspended drops on superhydrophobic surfaces.

  18. State of chemical modeling modules for the degradation of concrete and cements

    Energy Technology Data Exchange (ETDEWEB)

    Meike, A.

    1997-04-15

    This report describes the conceptual framework upon which modeling activities will be needed to predict the chemistry of water in contact with concrete and its degradation products cover a broad area, from developing databases for existing abiotic codes, to developing codes that can simulate the chemical impact of microbial activities at a level of sophistication equivalent to that of the abiotic modeling codes, and ultimately, to simulating drift-scale chemical systems in support of hydrological, geochemical,a nd engineering efforts.

  19. Mass Casualties and Health Care Following the Release of Toxic Chemicals or Radioactive Material—Contribution of Modern Biotechnology

    Science.gov (United States)

    Göransson Nyberg, Ann; Stricklin, Daniela; Sellström, Åke

    2011-01-01

    Catastrophic chemical or radiological events can cause thousands of casualties. Such disasters require triage procedures to identify the development of health consequences requiring medical intervention. Our objective is to analyze recent advancements in biotechnology for triage in mass emergency situations. In addition to identifying persons “at risk” of developing health problems, these technologies can aid in securing the unaffected or “worried well”. We also highlight the need for public/private partnerships to engage in some of the underpinning sciences, such as patho-physiological mechanisms of chemical and radiological hazards, and for the necessary investment in the development of rapid assessment tools through identification of biochemical, molecular, and genetic biomarkers to predict health effects. For chemical agents, biomarkers of neurotoxicity, lung damage, and clinical and epidemiological databases are needed to assess acute and chronic effects of exposures. For radiological exposures, development of rapid, sensitive biomarkers using advanced biotechnologies are needed to sort exposed persons at risk of life-threatening effects from persons with long-term risk or no risk. The final implementation of rapid and portable diagnostics tools suitable for emergency care providers to guide triage and medical countermeasures use will need public support, since commercial incentives are lacking. PMID:22408587

  20. Chemical pollution of environment in the cities of Central Siberia: risk for the health of the population

    Directory of Open Access Journals (Sweden)

    Ludmila Klimatskaya

    2015-03-01

    Full Text Available pollution in cities including the problem of risk assessment. The aim of the study is to determine carcinogenic and non-carcinogenic risks for the health of the population due to chemical contamination of air, water and food in the cities of the Krasnoyarsk region. Material and methods. The research was conducted in the Center of Hygiene and Epidemiology in the Krasnoyarsk region. 5122 samples of air, 4863 samples of water and 6915 samples of food stuff have been analyzed. Concentration of chemical substances was the base on which individual carcinogenesis risk (ICR and population carcinogenic conventional risks (PCCR and non carcinogenic risks [1] have been calculated. In the industrial cities chemical pollution of air, water and food stuff including carcinogenic substances creates carcinogenic and non-carcinogenic risks of morbidity of the population with the reinforcement of the complex impact, “with” which greatly exceeds the maximum acceptable risks. Results. Chemical pollution of environmental facilities in cities of the Krasnoyarsk region produce complex carcinogenic and non-carcinogenic risks which exceed maximum limit. The greatest shares in structure of complex carcinogenic risks are made in food stuff and water consumption in structure of complex non-carcinogenic risks as a result of air pollution and food stuff pollution. Conclusions. Obtained data could be used to set priorities in preventive measures to preserve health of the population in industrial cities of the Krasnoyarsk region.

  1. Developing health-based pre-planning clearance goals for airport remediation following chemical terrorist attack: Introduction and key assessment considerations

    Energy Technology Data Exchange (ETDEWEB)

    Watson, Annetta Paule [ORNL; Raber, Ellen [Lawrence Livermore National Laboratory (LLNL); Dolislager, Frederick [University of Tennessee, Knoxville (UTK); Hauschild, Veronique [U.S. Army Center for Health Promotion and Preventive Medicine; Hall, Dr. Linda [ENVIRON International Corporation; Love, Dr. Adam [Johnson Wright, Inc.

    2011-01-01

    In the event of a chemical terrorist attack on a transportation hub, post-event remediation and restoration activities necessary to attain unrestricted facility re-use and re-entry could require hours to multiple days. While restoration timeframes are dependent on numerous variables, a primary controlling factor is the level of pre-planning and decision-making completed prior to chemical terrorist release. What follows is the first of a two-part analysis identifying key considerations, critical information, and decision criteria to facilitate post-attack and post-decontamination consequence management activities. A conceptual site model and human health-based exposure guidelines are developed and reported as an aid to site-specific pre-planning in the current absence of U.S. state or Federal values designated as compound-specific remediation or re-entry concentrations, and to safely expedite facility recovery to full operational status. Chemicals of concern include chemical warfare nerve and vesicant agents and the toxic industrial compounds phosgene, hydrogen cyanide, and cyanogen chloride. This work has been performed as a national case study conducted in partnership with the Los Angeles International Airport and The Bradley International Terminal. All recommended guidelines have been selected for consistency with airport scenario release parameters of a one-time, short-duration, finite airborne release from a single source followed by compound-specific decontamination.

  2. Developing Health-Based Pre-Planning Clearance Goals for Airport Remediation Following Chemical Terrorist Attack: Introduction and Key Assessment Considerations

    Science.gov (United States)

    Watson, Annetta; Hall, Linda; Raber, Ellen; Hauschild, Veronique D.; Dolislager, Fredrick; Love, Adam H.; Hanna, M. Leslie

    2011-01-01

    In the event of a chemical terrorist attack on a transportation hub, post-event remediation and restoration activities necessary to attain unrestricted facility reuse and re-entry could require hours to multiple days. While restoration timeframes are dependent on numerous variables, a primary controlling factor is the level of pre-planning and decision-making completed prior to chemical terrorist release. What follows is the first of a two-part analysis identifying key considerations, critical information, and decision criteria to facilitate post-attack and post-decontamination consequence management activities. A conceptual site model and human health-based exposure guidelines are developed and reported as an aid to site-specific pre-planning in the current absence of U.S. state or Federal values designated as compound-specific remediation or re-entry concentrations, and to safely expedite facility recovery to full operational status. Chemicals of concern include chemical warfare nerve and vesicant agents and the toxic industrial compounds phosgene, hydrogen cyanide, and cyanogen chloride. This work has been performed as a national case study conducted in partnership with the Los Angeles International Airport and The Bradley International Terminal. All recommended guidelines have been selected for consistency with airport scenario release parameters of a one-time, short-duration, finite airborne release from a single source followed by compound-specific decontamination. PMID:21390292

  3. Information resources for assessing health effects from chemical exposure: Office of pesticides programs

    Energy Technology Data Exchange (ETDEWEB)

    Fenner-Crisp, P. [Environmental Protection Agency, Washington, DC (United States)

    1990-12-31

    The US Environmental Protection Agency (EPA) Office of Pesticide Programs is trying to develop a complete picture of a chemical`s toxicity and exposure profile. It is also important to share information in the office`s files because of pesticides, particularly as a consequence of agricultural use, find their way into places not necessarily intended.

  4. The Competence of Modelling in Learning Chemical Change: A Study with Secondary School Students

    Science.gov (United States)

    Oliva, José Mª; del Mar Aragón, María; Cuesta, Josefa

    2015-01-01

    The competence of modelling as part of learning about chemical change is analysed in a sample of 35 secondary students, ages 14-15 years, during their study of a curricular unit on this topic. The teaching approach followed is model based, with frequent use of analogies and mechanical models (fruits and bowls, Lego pieces, balls of plasticine,…

  5. A Review of Equation of State Models, Chemical Equilibrium Calculations and CERV Code Requirements for SHS Detonation Modelling

    Science.gov (United States)

    2009-10-01

    Beattie - Bridgeman Virial expansion The above equations are suitable for moderate pressures and are usually based on either empirical constants...CR 2010-013 October 2009 A Review of Equation of State Models, Chemical Equilibrium Calculations and CERV Code Requirements for SHS Detonation...Defence R&D Canada. A Review of Equation of State Models, Chemical Equilibrium Calculations and CERV Code Requirements for SHS Detonation

  6. A model linking clinical workforce skill mix planning to health and health care dynamics

    Directory of Open Access Journals (Sweden)

    McDonnell Geoff

    2010-04-01

    Full Text Available Abstract Background In an attempt to devise a simpler computable tool to assist workforce planners in determining what might be an appropriate mix of health service skills, our discussion led us to consider the implications of skill mixing and workforce composition beyond the 'stock and flow' approach of much workforce planning activity. Methods Taking a dynamic systems approach, we were able to address the interactions, delays and feedbacks that influence the balance between the major components of health and health care. Results We linked clinical workforce requirements to clinical workforce workload, taking into account the requisite facilities, technologies, other material resources and their funding to support clinical care microsystems; gave recognition to productivity and quality issues; took cognisance of policies, governance and power concerns in the establishment and operation of the health care system; and, going back to the individual, gave due attention to personal behaviour and biology within the socio-political family environment. Conclusion We have produced the broad endogenous systems model of health and health care which will enable human resource planners to operate within real world variables. We are now considering the development of simple, computable national versions of this model.

  7. Rules and recent trends for setting health-based occupational exposure limits for chemicals

    Directory of Open Access Journals (Sweden)

    Jolanta Skowroń

    2015-04-01

    Full Text Available The working environment is the special case of the non-natural environment created by man in which the increased production activity brings about the concentration of stimulators particularly aggressive to the human organism, such as chemical hazards, noise, vibration, extreme temperatures, and finally, intensified psychological and emotional stress. Depending on the nature and intensity, working environment factors have been classified into dangerous, harmful and annoying. The workers are more and more frequently exposed to dangerous chemicals in the working environment. The chemicals cause many diseases including, in the 1st place, respiratory insufficiency, inflammatory skin conditions, psychoneurological disorders and neoplastic diseases. Occupational exposure limit values (OELs, the main criteria for occupational exposure assessment, constitute an important factor for the safe use of chemicals in the working environment. In Poland, to date there are 524 chemical substances and 19 dusts for which maximum admissible concentrations (MAC have been established.

  8. Molecular modeling for the design of novel performance chemicals and materials

    CERN Document Server

    Rai, Beena

    2012-01-01

    Molecular modeling (MM) tools offer significant benefits in the design of industrial chemical plants and material processing operations. While the role of MM in biological fields is well established, in most cases MM works as an accessory in novel products/materials development rather than a tool for direct innovation. As a result, MM engineers and practitioners are often seized with the question: ""How do I leverage these tools to develop novel materials or chemicals in my industry?"" Molecular Modeling for the Design of Novel Performance Chemicals and Materials answers this important questio

  9. Toxicokinetic models and related tools in environmental risk assessment of chemicals.

    Science.gov (United States)

    Grech, Audrey; Brochot, Céline; Dorne, Jean-Lou; Quignot, Nadia; Bois, Frédéric Y; Beaudouin, Rémy

    2017-02-01

    Environmental risk assessment of chemicals for the protection of ecosystems integrity is a key regulatory and scientific research field which is undergoing constant development in modelling approaches and harmonisation with human risk assessment. This review focuses on state-of-the-art toxicokinetic tools and models that have been applied to terrestrial and aquatic species relevant to environmental risk assessment of chemicals. Both empirical and mechanistic toxicokinetic models are discussed using the results of extensive literature searches together with tools and software for their calibration and an overview of applications in environmental risk assessment. These include simple tools such as one-compartment models, multi-compartment models to physiologically-based toxicokinetic (PBTK) models, mostly available for aquatic species such as fish species and a number of chemical classes including plant protection products, metals, persistent organic pollutants, nanoparticles. Data gaps and further research needs are highlighted.

  10. Predicting carcinogenicity of diverse chemicals using probabilistic neural network modeling approaches

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Kunwar P., E-mail: kpsingh_52@yahoo.com [Academy of Scientific and Innovative Research, Council of Scientific and Industrial Research, New Delhi (India); Environmental Chemistry Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow 226 001 (India); Gupta, Shikha; Rai, Premanjali [Academy of Scientific and Innovative Research, Council of Scientific and Industrial Research, New Delhi (India); Environmental Chemistry Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow 226 001 (India)

    2013-10-15

    Robust global models capable of discriminating positive and non-positive carcinogens; and predicting carcinogenic potency of chemicals in rodents were developed. The dataset of 834 structurally diverse chemicals extracted from Carcinogenic Potency Database (CPDB) was used which contained 466 positive and 368 non-positive carcinogens. Twelve non-quantum mechanical molecular descriptors were derived. Structural diversity of the chemicals and nonlinearity in the data were evaluated using Tanimoto similarity index and Brock–Dechert–Scheinkman statistics. Probabilistic neural network (PNN) and generalized regression neural network (GRNN) models were constructed for classification and function optimization problems using the carcinogenicity end point in rat. Validation of the models was performed using the internal and external procedures employing a wide series of statistical checks. PNN constructed using five descriptors rendered classification accuracy of 92.09% in complete rat data. The PNN model rendered classification accuracies of 91.77%, 80.70% and 92.08% in mouse, hamster and pesticide data, respectively. The GRNN constructed with nine descriptors yielded correlation coefficient of 0.896 between the measured and predicted carcinogenic potency with mean squared error (MSE) of 0.44 in complete rat data. The rat carcinogenicity model (GRNN) applied to the mouse and hamster data yielded correlation coefficient and MSE of 0.758, 0.71 and 0.760, 0.46, respectively. The results suggest for wide applicability of the inter-species models in predicting carcinogenic potency of chemicals. Both the PNN and GRNN (inter-species) models constructed here can be useful tools in predicting the carcinogenicity of new chemicals for regulatory purposes. - Graphical abstract: Figure (a) shows classification accuracies (positive and non-positive carcinogens) in rat, mouse, hamster, and pesticide data yielded by optimal PNN model. Figure (b) shows generalization and predictive

  11. A chemical and petrological model of the lunar crust

    Science.gov (United States)

    Spudis, Paul D.; Davis, Philip A.

    1987-01-01

    Information is given on the composition and structure of the lunar crust. A lunar model is illustrated, indicating that it has essentially two layers, anorthositic mixed rocks overlaying a generally noritic crystalline basement. Implications relative to lunar evolution are discussed.

  12. SewageLCI 1.0 - A first generation inventory model for quantification of chemical emissions via sewage systems. Application on chemicals of concern

    DEFF Research Database (Denmark)

    Gallice, Aurélie; Birkved, Morten; Kech, Sébastien

    Lack of inventory data on chemical emissions often forces life cycle assessors to rely on crude emissions estimates (e.g. 100 % of the applied chemical mass is assumed emitted) or in the worst case to omit chemical emissions due to lack of emission data. The inventory model SewageLCI 1.0, provides...... a mean for assessors to obtain fractions of chemicals emitted to the environment via waste water collection and treatment systems. SewageLCI 1.0 is based on existing models capable of estimating chemical degradation in waste water collection and treatment systems and also on national European statistics...... concerning waste water treatment systems. By combining readily available statistics and models stemming from environmental chemistry and waste water treatment science, the SewageLCI 1.0 model was built to simulate national specific average waste water collection and treatment systems and the model is hence...

  13. Building a sustainable Academic Health Department: the South Carolina model.

    Science.gov (United States)

    Smith, Lillian Upton; Waddell, Lisa; Kyle, Joseph; Hand, Gregory A

    2014-01-01

    Given the limited resources available to public health, it is critical that university programs complement the development needs of agencies. Unfortunately, academic and practice public health entities have long been challenged in building sustainable collaborations that support practice-based research, teaching, and service. The academic health department concept offers a promising solution. In South Carolina, the partners started their academic health department program with a small grant that expanded into a dynamic infrastructure that supports innovative professional exchange and development programs. This article provides a background and describes the key elements of the South Carolina model: joint leadership, a multicomponent memorandum of agreement, and a shared professional development mission. The combination of these elements allows the partners to leverage resources and deftly respond to challenges and opportunities, ultimately fostering the sustainability of the collaboration.

  14. A consumer involvement model for health technology assessment in Canada.

    Science.gov (United States)

    Pivik, Jayne; Rode, Elisabeth; Ward, Christopher

    2004-08-01

    Similar to other health policy initiatives, there is a growing movement to involve consumers in decisions affecting their treatment options. Access to treatments can be impacted by decisions made during a health technology assessment (HTA), i.e., the rigorous assessment of medical interventions such as drugs, vaccines, devices, materials, medical and surgical procedures and systems. The purpose of this paper was to empirically assess the interest and potential mechanisms for consumer involvement in HTA by identifying what health consumer organizations consider meaningful involvement, examining current practices internationally and developing a model for involvement based on identified priorities and needs. Canadian health consumer groups representing the largest disease or illness conditions reported a desire for involvement in HTA and provided feedback on mechanisms for facilitating their involvement.

  15. Modeling the elution of organic chemicals from a melting homogeneous snow pack.

    Science.gov (United States)

    Meyer, Torsten; Wania, Frank

    2011-06-01

    Organic chemicals are often released in peak concentrations from melting snow packs. A simple, mechanistic snowmelt model was developed to simulate and predict the elution of organic substances from melting, homogeneous snow, as influenced by chemical properties and snow pack characteristics. The model calculates stepwise the chemical transport along with the melt water flow in a multi-layered snow pack, based on chemical equilibrium partitioning between the individual bulk snow phases. The model succeeds in reproducing the elution behavior of several organic contaminants observed in previously conducted cold room experiments. The model aided in identifying four different types of enrichment of organic substances during snowmelt. Water soluble substances experience peak releases early during a melt period (type 1), whereas chemicals that strongly sorb to particulate matter (PM) or snow grain surfaces elute at the end of melting (type 2). Substances that are somewhat water soluble and at the same time have a high affinity for snow grain surfaces may exhibit increasing concentrations in the melt water (type 3). Finally, elution sequences involving peak loads both at the beginning and the end of melting are simulated for chemicals that are partially dissolved in the aqueous melt water phase and partially sorbed to PM (type 4). The extent of type 1 enrichment mainly depends on the snow depth, whereby deeper snow generates more pronounced concentration peaks. PM influences the elution behavior of organic chemicals strongly because of the very large natural variability in the type and amount of particles present in snow. Urban and road-side snow rich in PM can generate type 2 concentration peaks at the end of the melt period for even relatively water soluble substances. From a clean, melting snow pack typical for remote regions, even fairly hydrophobic chemicals can be released in type 1 mode while being almost completely dissolved in the aqueous melt water phase. The

  16. A model for planning the chemical integrated system under uncertainty by the grey programming approach

    DEFF Research Database (Denmark)

    Ren, Jingzheng; Tan, Shiyu; Dong, Lichun

    2013-01-01

    A model to optimize the planning of the chemical integrated system comprised by multi-devices and multi-products has been proposed in this paper. With the objective to make more profits, the traditional model for optimizing production planning has been proposed. The price of chemicals, the market...... demand, and the production capacity have been considered as mutative variables, then an improved model in which some parameters are not constant has been developed and a new method to solve the grey linear programming has been proposed. In the grey programming model, the value of credibility can...

  17. Mathematical Modeling of Tin-Free Chemically-Active Antifouling Paint Behavior

    DEFF Research Database (Denmark)

    Yebra, Diego Meseguer; Kiil, Søren; Dam-Johansen, Kim

    2006-01-01

    Mathematical modeling has been used to characterize and validate the working mechanisms of tin-free, chemically-active antifouling (AF) paints. The model-based analysis of performance data from lab-scale rotary experiments has shown significant differences between antifouling technologies...... as regards the biocide leaching and the surface polishing processes. Hence, the modeling framework developed in this work is built so as to describe any generic, chemically-active AF paint through model parameters, the values of which can be obtained or adjusted from relatively fast measurements...

  18. An insight into chemical kinetics and turbulence-chemistry interaction modeling in flameless combustion

    Directory of Open Access Journals (Sweden)

    Amir Azimi, Javad Aminian

    2015-01-01

    Full Text Available Computational Fluid Dynamics (CFD study of flameless combustion condition is carried out by solving the Reynolds-Averaged Navier-Stokes (RANS equations in the open-source CFD package of OpenFOAM 2.1.0. Particular attention is devoted to the comparison of three global and detailed chemical mechanisms using the Partially Stirred Reactor (PaSR combustion model for the turbulence-chemistry interaction treatment. The OpenFOAM simulations are assessed against previously published CFD results using the Eddy Dissipation Concept (EDC combustion model as well as the experimental data available in the literature. Results show that global chemical mechanisms provide acceptable predictions of temperature and major species fields in flameless mode with much lower computational costs comparing with the detailed chemical mechanisms. However, incorporation of detailed chemical mechanisms with proper combustion models is crucial to account for finite-rate chemistry effects and accurately predict net production of minor species.

  19. Chemical genetics and drug screening in Drosophila cancer models

    Institute of Scientific and Technical Information of China (English)

    Mara Gladstone; Tin Tin Su

    2011-01-01

    Drug candidates often fail in preclinical and clinical testing because of reasons of efficacy and/or safety.It would be time- and cost-efficient to have screening models that reduce the rate of such false positive candidates that appear promising at first but fail later.In this regard,it would be particularly useful to have a rapid and inexpensive whole animal model that can pre-select hits from high-throughput screens but before testing in costly rodent assays.Drosophila melanogaster has emerged as a potential whole animal model for drug screening.Of particular interest have been drugs that must act in the context of multi-cellularity such as those for neurological disorders and cancer.A recent review provides a comprehensive summary of drug screening in Drosophila,but with an emphasis on neurodegenerative disorders.Here,we review Drosophila screens in the literature aimed at cancer therapeutics.

  20. [Science, health and education: a priority and a model].

    Science.gov (United States)

    Fúster, Valentin

    2010-01-01

    Myocardial infarction and brain infarction are personally dramatic events. However, these cardiovascular events are also globally dramatic not just for being the first cause of death all over the world. In addition, their prevalence is increasing and the high economic cost of treatment - technological and pharmacological - is already inaccessible in many regions of the world. In light of the above, we have established an international foundation under the priority concept "Science, Health and Education" (SHE). This fundation is based in a new Spanish research and funding model, the "Nacional Cardiovascular Research Center (CNIC). The research aspect is geared towards promoting cardiovascular health and disease management both individually and among the population. Funding is public and private, excluding the fharmaceutical industry, wich thus prevents conflicts of interest. In the cardiovascular setting, the entity SHE as conceptual priority, and the CNIC as Scientific basis or model can be pilot or applicable to other health and disease issues in general.

  1. Distributed Data Storage Model for Cattle Health Monitoring Using WSN

    Directory of Open Access Journals (Sweden)

    Ankit R. Bhavsar

    2013-05-01

    Full Text Available Now a day, wireless sensor networks (WSN are being deployed in various applications like industrial, environmental, health care, societal monitoring. The sensor networks have tendency to generate huge amount of data. Hence data storage techniques become a critical issue for the success of these applications. In this paper, we have proposed a distributed data storage model used for WSN based cattle health monitoring. We have also defined the structure for the same. We have divided this model into two levels namely a local level and a central level. The main aim of storing data locally is to get quick response for any query raised by the user. The second level where the data is centralized is used to make long term decision, planning and policy for the cattle health monitoring.

  2. Physical/chemical modeling for photovoltaic module life prediction

    Science.gov (United States)

    Moacanin, J.; Carroll, W. F.; Gupta, A.

    1979-01-01

    The paper presents a generalized methodology for identification and evaluation of potential degradation and failure of terrestrial photovoltaic encapsulation. Failure progression modeling and an interaction matrix are utilized to complement the conventional approach to failure degradation mode identification. Comparison of the predicted performance based on these models can produce: (1) constraints on system or component design, materials or operating conditions, (2) qualification (predicted satisfactory function), and (3) uncertainty. The approach has been applied to an investigation of an unexpected delamination failure; it is being used to evaluate thermomechanical interactions in photovoltaic modules and to study corrosion of contacts and interconnects.

  3. Managing Dog Waste: Campaign Insights from the Health Belief Model

    Science.gov (United States)

    Typhina, Eli; Yan, Changmin

    2014-01-01

    Aiming to help municipalities develop effective education and outreach campaigns to reduce stormwater pollutants, such as pet waste, this study applied the Health Belief Model (HBM) to identify perceptions of dog waste and corresponding collection behaviors from dog owners living in a small U.S. city. Results of 455 online survey responses…

  4. Models and Methods for Assessing Refugee Mental Health Needs.

    Science.gov (United States)

    Deinard, Amos S.; And Others

    This background paper on refugee needs assessment discusses the assumptions, goals, objectives, strategies, models, and methods that the state refugee programs can consider in designing their strategies for assessing the mental health needs of refugees. It begins with a set of background assumptions about the ethnic profile of recent refugee…

  5. Permitted Suicide: Model Roles for Mental Health Counseling.

    Science.gov (United States)

    Cohen, Elliot D.

    2001-01-01

    In mental health practice, no explicit provisions have been made for existing law and codes of ethics to protect freedom and confidences of clients who rationally desire to end their lives. Makes a case for permitting suicide by providing an analysis of permitted suicide, the legal background for applying this concept, and ten model rules for…

  6. Optimization of a Reduced Chemical Kinetic Model for HCCI Engine Simulations by Micro-Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A reduced chemical kinetic model (44 species and 72 reactions) for the homogeneous charge compression ignition (HCCI) combustion of n-heptane was optimized to improve its autoignition predictions under different engine operating conditions. The seven kinetic parameters of the optimized model were determined by using the combination of a micro-genetic algorithm optimization methodology and the SENKIN program of CHEMKIN chemical kinetics software package. The optimization was performed within the range of equivalence ratios 0.2-1.2, initial temperature 310-375 K and initial pressure 0.1-0.3 MPa. The engine simulations show that the optimized model agrees better with the detailed chemical kinetic model (544 species and 2 446 reactions) than the original model does.

  7. A Chemical Model of Micrometeorite Impact into Olivine

    Science.gov (United States)

    Sheffer, A. A.; Melosh, H. J.

    2005-01-01

    Laboratory simulations of space weathering using laser irradiation have been successful in reproducing space weathering characteristics such as the reduction of olivine to form nanophase iron particles. However, the chemistry of the reduction of Fe2+ in olivine to Fe metal has not been fully explored. We present a thermodynamic model of olivine undergoing post-impact cooling and decompression.

  8. Natural products--a simple model to explain chemical diversity.

    Science.gov (United States)

    Firn, Richard D; Jones, Clive G

    2003-08-01

    A simple evolutionary model is presented which explains why organisms produce so many natural products, why so many have low biological activity, why enzymes involved in natural product synthesis have the properties they do and why natural product metabolism is shaped as it is.

  9. Thermo-Chemical Modelling Strategies for the Pultrusion Process

    DEFF Research Database (Denmark)

    Baran, Ismet; Hattel, Jesper Henri; Tutum, Cem Celal

    2013-01-01

    In the present study, three dimensional (3D) numerical modeling strategies of a thermosetting pultrusion process are investigated considering both transient and steady state approaches. For the transient solution, an unconditionally stable alternating direction implicit Douglas-Gunn (ADI-DG) sche...

  10. Prediction of aged red wine aroma properties from aroma chemical composition. Partial least squares regression models.

    Science.gov (United States)

    Aznar, Margarita; López, Ricardo; Cacho, Juan; Ferreira, Vicente

    2003-04-23

    Partial least squares regression (PLSR) models able to predict some of the wine aroma nuances from its chemical composition have been developed. The aromatic sensory characteristics of 57 Spanish aged red wines were determined by 51 experts from the wine industry. The individual descriptions given by the experts were recorded, and the frequency with which a sensory term was used to define a given wine was taken as a measurement of its intensity. The aromatic chemical composition of the wines was determined by already published gas chromatography (GC)-flame ionization detector and GC-mass spectrometry methods. In the whole, 69 odorants were analyzed. Both matrixes, the sensory and chemical data, were simplified by grouping and rearranging correlated sensory terms or chemical compounds and by the exclusion of secondary aroma terms or of weak aroma chemicals. Finally, models were developed for 18 sensory terms and 27 chemicals or groups of chemicals. Satisfactory models, explaining more than 45% of the original variance, could be found for nine of the most important sensory terms (wood-vanillin-cinnamon, animal-leather-phenolic, toasted-coffee, old wood-reduction, vegetal-pepper, raisin-flowery, sweet-candy-cacao, fruity, and berry fruit). For this set of terms, the correlation coefficients between the measured and predicted Y (determined by cross-validation) ranged from 0.62 to 0.81. Models confirmed the existence of complex multivariate relationships between chemicals and odors. In general, pleasant descriptors were positively correlated to chemicals with pleasant aroma, such as vanillin, beta damascenone, or (E)-beta-methyl-gamma-octalactone, and negatively correlated to compounds showing less favorable odor properties, such as 4-ethyl and vinyl phenols, 3-(methylthio)-1-propanol, or phenylacetaldehyde.

  11. A path forward in the debate over health impacts of endocrine disrupting chemicals

    DEFF Research Database (Denmark)

    Zoeller, Robert T; Bergmann, Åke; Becher, Georg;

    2014-01-01

    Several recent publications reflect debate on the issue of "endocrine disrupting chemicals" (EDCs), indicating that two seemingly mutually exclusive perspectives are being articulated separately and independently. Considering this, a group of scientists with expertise in basic science, medicine...

  12. Technical Report on chemicals, particulate matter and human health, air quality and noise

    NARCIS (Netherlands)

    Smeets W; Pull A van; Eerens H; Sluyter R; Hollander G de; MNV

    2001-01-01

    The economic assessment of priorities for a European environmental policy plan focuses on twelve identified Prominent European Environmental Problems such as climate change, chemical risks and biodiversity. The study, commissioned by the European Commission (DG Environment) to a European consortium

  13. Development of chemical kinetic models for lean NOx traps.

    Energy Technology Data Exchange (ETDEWEB)

    Larson, Richard S.

    2010-04-01

    Overall project goal: Obtain the fundamental surface chemistry knowledge needed for the design and optimal utilization of NOx trap catalysts, thereby helping to speed the widespread adoption of this technology. Relevance to VT Program goals: Effective, durable advanced aftertreatment systems for lean-burn engines must be available if the fuel economy advantages of these engines are to be realized. Specific current year objective: Identify and correct any deficiencies in the previously developed reaction mechanism describing normal storage/regeneration cycles, and complete development of a supplementary mechanism accounting for the effects of sulfation. A fundamental understanding of LNT chemistry is needed to realize the full potential of this aftertreatment technology, which could lead to greater use of fuel-efficient lean-burn engines. We have used a multi-tiered approach to developing an elementary chemical mechanism benchmarked against experimental data: (1) Simulate a set of steady flow experiments, with storage effects minimized, to infer a tentative mechanism for chemistry on precious metal sites (completed). (2) Simulate a set of long cycle experiments to infer a mechanism for NOx and oxygen storage sites while simultaneously finalizing precious metal chemistry (completed). (3) Simulate a simplified sulfation/desulfation protocol to obtain a supplementary set of reactions involving sulfur on all three kinds of sites (nearly completed). (4) Investigate the potential role of reductants other than CO and H{sub 2}. While simulation of isothermal experiments is the preferred way to extract kinetic parameters, simulation of realistic storage/regeneration cycles requires that exotherms be considered. Our ultimate goal is to facilitate improved designs for LNT-based aftertreatment systems and to assist in the development of improved catalysts.

  14. Multispecies QSAR modeling for predicting the aquatic toxicity of diverse organic chemicals for regulatory toxicology.

    Science.gov (United States)

    Singh, Kunwar P; Gupta, Shikha; Kumar, Anuj; Mohan, Dinesh

    2014-05-19

    The research aims to develop multispecies quantitative structure-activity relationships (QSARs) modeling tools capable of predicting the acute toxicity of diverse chemicals in various Organization for Economic Co-operation and Development (OECD) recommended test species of different trophic levels for regulatory toxicology. Accordingly, the ensemble learning (EL) approach based classification and regression QSAR models, such as decision treeboost (DTB) and decision tree forest (DTF) implementing stochastic gradient boosting and bagging algorithms were developed using the algae (P. subcapitata) experimental toxicity data for chemicals. The EL-QSAR models were successfully applied to predict toxicities of wide groups of chemicals in other test species including algae (S. obliguue), daphnia, fish, and bacteria. Structural diversity of the selected chemicals and those of the end-point toxicity data of five different test species were tested using the Tanimoto similarity index and Kruskal-Wallis (K-W) statistics. Predictive and generalization abilities of the constructed QSAR models were compared using statistical parameters. The developed QSAR models (DTB and DTF) yielded a considerably high classification accuracy in complete data of model building (algae) species (97.82%, 99.01%) and ranged between 92.50%-94.26% and 92.14%-94.12% in four test species, respectively, whereas regression QSAR models (DTB and DTF) rendered high correlation (R(2)) between the measured and model predicted toxicity end-point values and low mean-squared error in model building (algae) species (0.918, 0.15; 0.905, 0.21) and ranged between 0.575 and 0.672, 0.18-0.51 and 0.605-0.689 and 0.20-0.45 in four different test species. The developed QSAR models exhibited good predictive and generalization abilities in different test species of varied trophic levels and can be used for predicting the toxicities of new chemicals for screening and prioritization of chemicals for regulation.

  15. Fundamental modeling issues on benchmark structure for structural health monitoring

    Institute of Scientific and Technical Information of China (English)

    LI HuaJun; ZHANG Min; WANG JunRong; HU Sau-Lon James

    2009-01-01

    The IASC-ASCE Structural Health Monitoring Task Group developed a series of benchmark problems,and participants of the benchmark study were charged with using a 12-degree-of-freedom (DOF) shear building as their identification model. The present article addresses improperness, including the parameter and modeling errors, of using this particular model for the intended purpose of damage detection, while the measurements of damaged structures are synthesized from a full-order finite-element model. In addressing parameter errors, a model calibration procedure is utilized to tune the mass and stiffness matrices of the baseline identification model, and a 12-DOF shear building model that preserves the first three modes of the full-order model is obtained. Sequentially, this calibrated model is employed as the baseline model while performing the damage detection under various damage scenarios. Numerical results indicate that the 12-DOF shear building model is an over-simplified identification model, through which only idealized damage situations for the benchmark structure can be detected. It is suggested that a more sophisticated 3-dimensional frame structure model should be adopted as the identification model, if one intends to detect local member damages correctly.

  16. Fundamental modeling issues on benchmark structure for structural health monitoring

    Institute of Scientific and Technical Information of China (English)

    HU; Sau-Lon; James

    2009-01-01

    The IASC-ASCE Structural Health Monitoring Task Group developed a series of benchmark problems, and participants of the benchmark study were charged with using a 12-degree-of-freedom (DOF) shear building as their identification model. The present article addresses improperness, including the parameter and modeling errors, of using this particular model for the intended purpose of damage detec- tion, while the measurements of damaged structures are synthesized from a full-order finite-element model. In addressing parameter errors, a model calibration procedure is utilized to tune the mass and stiffness matrices of the baseline identification model, and a 12-DOF shear building model that preserves the first three modes of the full-order model is obtained. Sequentially, this calibrated model is employed as the baseline model while performing the damage detection under various damage scenarios. Numerical results indicate that the 12-DOF shear building model is an over-simplified identification model, through which only idealized damage situations for the benchmark structure can be detected. It is suggested that a more sophisticated 3-dimensional frame structure model should be adopted as the identification model, if one intends to detect local member damages correctly.

  17. Electronic Health Record Patient Portal Adoption by Health Care Consumers: An Acceptance Model and Survey

    Science.gov (United States)

    2016-01-01

    Background The future of health care delivery is becoming more citizen centered, as today’s user is more active, better informed, and more demanding. Worldwide governments are promoting online health services, such as electronic health record (EHR) patient portals and, as a result, the deployment and use of these services. Overall, this makes the adoption of patient-accessible EHR portals an important field to study and understand. Objective The aim of this study is to understand the factors that drive individuals to adopt EHR portals. Methods We applied a new adoption model using, as a starting point, Ventkatesh's Unified Theory of Acceptance and Use of Technology in a consumer context (UTAUT2) by integrating a new construct specific to health care, a new moderator, and new relationships. To test the research model, we used the partial least squares (PLS) causal modelling approach. An online questionnaire was administrated. We collected 360 valid responses. Results The statistically significant drivers of behavioral intention are performance expectancy (beta=.200; t=3.619), effort expectancy (beta=.185; t=2.907), habit (beta=.388; t=7.320), and self-perception (beta=.098; t=2.285). The predictors of use behavior are habit (beta=0.206; t=2.752) and behavioral intention (beta=0.258; t=4.036). The model explained 49.7% of the variance in behavioral intention and 26.8% of the variance in use behavior. Conclusions Our research helps to understand the desired technology characteristics of EHR portals. By testing an information technology acceptance model, we are able to determine what is more valued by patients when it comes to deciding whether to adopt EHR portals or not. The inclusion of specific constructs and relationships related to the health care consumer area also had a significant impact on understanding the adoption of EHR portals. PMID:26935646

  18. Health benefit modelling and optimization of vehicular pollution control strategies

    Science.gov (United States)

    Sonawane, Nayan V.; Patil, Rashmi S.; Sethi, Virendra

    2012-12-01

    This study asserts that the evaluation of pollution reduction strategies should be approached on the basis of health benefits. The framework presented could be used for decision making on the basis of cost effectiveness when the strategies are applied concurrently. Several vehicular pollution control strategies have been proposed in literature for effective management of urban air pollution. The effectiveness of these strategies has been mostly studied as a one at a time approach on the basis of change in pollution concentration. The adequacy and practicality of such an approach is studied in the present work. Also, the assessment of respective benefits of these strategies has been carried out when they are implemented simultaneously. An integrated model has been developed which can be used as a tool for optimal prioritization of various pollution management strategies. The model estimates health benefits associated with specific control strategies. ISC-AERMOD View has been used to provide the cause-effect relation between control options and change in ambient air quality. BenMAP, developed by U.S. EPA, has been applied for estimation of health and economic benefits associated with various management strategies. Valuation of health benefits has been done for impact indicators of premature mortality, hospital admissions and respiratory syndrome. An optimization model has been developed to maximize overall social benefits with determination of optimized percentage implementations for multiple strategies. The model has been applied for sub-urban region of Mumbai city for vehicular sector. Several control scenarios have been considered like revised emission standards, electric, CNG, LPG and hybrid vehicles. Reduction in concentration and resultant health benefits for the pollutants CO, NOx and particulate matter are estimated for different control scenarios. Finally, an optimization model has been applied to determine optimized percentage implementation of specific

  19. Assessing the Physical Activity of Health Volunteers Based on the Pender’s Health Promotion Model

    Directory of Open Access Journals (Sweden)

    Rahimian M.* MSc,

    2015-12-01

    Full Text Available Aims Physical inactivity has been identified as the 4th leading risk factor for global mortality causing an estimated of 3.2million deaths per year. This study aimed to assess the physical activity of health volunteers with Pender’s Health Promotion Model. Instrument & Methods This cross-sectional analytical study was performed on 80 health volunteers in Torbat-e-Jam City, Iran, in 2015. A researcher-made questionnaire with the following sections was used to gather data; perceived benefits, perceived barriers, selfefficacy, interpersonal influences, positive emotion, commitment, modeling and competing preferences. SPSS 16 sofware was used to analyze data by independent T, Pearson’s correlation coefficient and linear regression tests. Findings There was no significant difference between the scores according to educational levels, age groups, BMI score, marital status, habitat and experience as a health volunteer duration. Physical activity had positive correlation with perceived benefits, self-efficacy, commitment, positive emotion and situational influences and a negative correlation with perceived barriers. Situational influences, as the strongest predictor of the physical activity, predicted 35.1% of it and then positive emotions predicted 34.7% and self-efficacy predicted 23.4% of physical activity. Conclusion The level of physical activity in health volunteers of Torbat-e-Jam City, Iran, is not appropriate and is less than moderate.

  20. A Chemical Containment Model for the General Purpose Work Station

    Science.gov (United States)

    Flippen, Alexis A.; Schmidt, Gregory K.

    1994-01-01

    Contamination control is a critical safety requirement imposed on experiments flying on board the Spacelab. The General Purpose Work Station, a Spacelab support facility used for life sciences space flight experiments, is designed to remove volatile compounds from its internal airpath and thereby minimize contamination of the Spacelab. This is accomplished through the use of a large, multi-stage filter known as the Trace Contaminant Control System. Many experiments planned for the Spacelab require the use of toxic, volatile fixatives in order to preserve specimens prior to postflight analysis. The NASA-Ames Research Center SLS-2 payload, in particular, necessitated the use of several toxic, volatile compounds in order to accomplish the many inflight experiment objectives of this mission. A model was developed based on earlier theories and calculations which provides conservative predictions of the resultant concentrations of these compounds given various spill scenarios. This paper describes the development and application of this model.

  1. Personality is of central concern to understand health: towards a theoretical model for health psychology.

    Science.gov (United States)

    Ferguson, Eamonn

    2013-05-01

    This paper sets out the case that personality traits are central to health psychology. To achieve this, three aims need to be addressed. First, it is necessary to show that personality influences a broad range of health outcomes and mechanisms. Second, the simple descriptive account of Aim 1 is not sufficient, and a theoretical specification needs to be developed to explain the personality-health link and allow for future hypothesis generation. Third, once Aims 1 and 2 are met, it is necessary to demonstrate the clinical utility of personality. In this review I make the case that all three Aims are met. I develop a theoretical framework to understand the links between personality and health drawing on current theorising in the biology, evolution, and neuroscience of personality. I identify traits (i.e., alexithymia, Type D, hypochondriasis, and empathy) that are of particular concern to health psychology and set these within evolutionary cost-benefit analysis. The literature is reviewed within a three-level hierarchical model (individual, group, and organisational) and it is argued that health psychology needs to move from its traditional focus on the individual level to engage group and organisational levels.

  2. The evolution of the Fenway Community Health model.

    Science.gov (United States)

    Mayer, K; Appelbaum, J; Rogers, T; Lo, W; Bradford, J; Boswell, S

    2001-06-01

    Fenway Community Health was founded by community activists in 1971 in the Fenway neighborhood of Boston, Mass, and within a decade had rapidly expanded its medical services for gay men in response to the AIDS epidemic. Increased expertise and cultural competence in lesbian, gay, bisexual, and transgender (LGBT) care led to expansion of medical services to address broader community concerns, ranging from substance use to parenting issues to domestic and homophobic violence, as well as specialized programs for lesbians, bisexuals, and transgendered individuals. Fenway began as a grassroots neighborhood clinic. In 1975, the center recorded 5000 patient care visits; in 2000, Fenway's clinical departments recorded 50,850 visits by 8361 individuals, including more than 1100 individuals receiving HIV-associated care. The center now has more than 170 staff people responsible for clinical programs, community education, research, administration, planning, and development. Over the past few years, Fenway's annual budget has exceeded $10 million. Fenway has established standards for improved cultural competence about LGBT health issues for other health providers and has developed programs to educate the general community about specific LGBT health concerns. This health center may provide a model of comprehensive LGBT health services that have a local impact.

  3. Dynamic modeling of chemical fate and transport in multimedia environments at watershed scale-I: theoretical considerations and model implementation.

    Science.gov (United States)

    Luo, Yuzhou; Gao, Qiong; Yang, Xiusheng

    2007-04-01

    A geo-referenced environmental fate model was developed for analyzing unsteady-state dispersion and distribution of chemicals in multimedia environmental systems. Chemical transport processes were formulated in seven environmental compartments of air, canopy, surface soil, root-zone soil, vadose-zone soil, surface water, and sediment. The model assumed that the compartments were completely mixed and chemical equilibrium was established instantaneously between the sub-compartments within each compartment. A fugacity approach was utilized to formulate the mechanisms of diffusion, advection, physical interfacial transport, and transformation reactions. The governing equations of chemical mass balances in the environmental compartments were solved simultaneously to reflect the interactions between the compartments. A geographic information system (GIS) database and geospatial analysis were integrated into the chemical transport simulation to provide spatially explicit estimations of model parameters at watershed scale. Temporal variations of the environmental properties and source emissions were also considered in the parameter estimations. The outputs of the model included time-dependent chemical concentrations in each compartment and its sub-compartments, and inter-media mass fluxes between adjacent compartments at daily time steps.

  4. Improved Chemical Structure-Activity Modeling Through Data Augmentation.

    Science.gov (United States)

    Cortes-Ciriano, Isidro; Bender, Andreas

    2015-12-28

    Extending the original training data with simulated unobserved data points has proven powerful to increase both the generalization ability of predictive models and their robustness against changes in the structure of data (e.g., systematic drifts in the response variable) in diverse areas such as the analysis of spectroscopic data or the detection of conserved domains in protein sequences. In this contribution, we explore the effect of data augmentation in the predictive power of QSAR models, quantified by the RMSE values on the test set. We collected 8 diverse data sets from the literature and ChEMBL version 19 reporting compound activity as pIC50 values. The original training data were replicated (i.e., augmented) N times (N ∈ 0, 1, 2, 4, 6, 8, 10), and these replications were perturbed with Gaussian noise (μ = 0, σ = σnoise) on either (i) the pIC50 values, (ii) the compound descriptors, (iii) both the compound descriptors and the pIC50 values, or (iv) none of them. The effect of data augmentation was evaluated across three different algorithms (RF, GBM, and SVM radial) and two descriptor types (Morgan fingerprints and physicochemical-property-based descriptors). The influence of all factor levels was analyzed with a balanced fixed-effect full-factorial experiment. Overall, data augmentation constantly led to increased predictive power on the test set by 10-15%. Injecting noise on (i) compound descriptors or on (ii) both compound descriptors and pIC50 values led to the highest drop of RMSEtest values (from 0.67-0.72 to 0.60-0.63 pIC50 units). The maximum increase in predictive power provided by data augmentation is reached when the training data is replicated one time. Therefore, extending the original training data with one perturbed repetition thereof represents a reasonable trade-off between the increased performance of the models and the computational cost of data augmentation, namely increase of (i) model complexity due to the need for optimizing

  5. MODEL OF HEALTH TOURISM DEVELOPMENT - SPA TOURISM CLUSTER IN ROMANIA

    Directory of Open Access Journals (Sweden)

    Daniela FUNDEANU

    2015-06-01

    Full Text Available Health tourism occupies an important place in the preferences of tourists and represents one of the major sources of revenue for Romania, a country rich in resources spas. Romania holds spas with tourism potential, but which require investments in infrastructure, to work to the standards required of a modern tourism. The need of valorization of balneology potential of the regions to increase regional competitiveness, global and national, has led to the appearance of PPP forms adapted to the particularities of the tourist industry. We develop a collaborative model in which the balneology destinations can become leaders of European health tourism.

  6. Numerical aspects of modelling of coupled chemical reactions and fluid flow in sedimentary basins

    Energy Technology Data Exchange (ETDEWEB)

    Holstad, Astrid

    1998-01-01

    Simulation of coupled chemical reactions and fluid flow in porous sedimentary basins, through long time periods, is a numerical challenge. In most models available today the equations representing such a physical problem are solved as PDEs (Partial Differential Equation) where efficient time-stepping with controlled error is very difficult. The DAE (Differential Algebraic Equation) system approach is used where robust adaptive time-stepping algorithms are available in solvers. In this report mathematical and numerical models are derived for coupled chemical reactions and fluid flow. The models have several interesting properties which are discussed. The performance of code is tested. 20 refs., 6 figs., 2 tabs.

  7. Modelling counter-current chromatography: a chemical engineering perspective.

    Science.gov (United States)

    Kostanian, A E

    2002-10-11

    In conventional chromatography, a solute is usually viewed to be longitudinally transported only in the mobile phase, remaining longitudinally motionless in the stationary phase. In counter-current chromatography, both phases undergo intense mixing in the variable force field of a coil planet centrifuge and longitudinal dispersion of matter in the stationary phase is not to be excluded. To take into account longitudinal mixing in both phases, a cell model of chromatographic process is proposed in which the number of perfectly mixed cells n is determined by the rates of mixing in stationary (Ds) and mobile (Dm) phases by the equation n = LF/(2ADc)/(1 + Sf(lambda - 1)) with A = K(D)D(S)/Dm (F, L, Ac and KD are the mobile phase flow-rate, column length, column cross-section and distribution ratio, respectively). This equation has been derived by comparing the discontinuous cell model with continuous diffusion assuming equilibrium conditions. Parameter determination and their relationships are discussed.

  8. Chemical kinetic modeling of a methane opposed flow diffusion flame and comparison to experiments

    Energy Technology Data Exchange (ETDEWEB)

    Marinov, N.M., Pitz, W.J.; Westbrook, C.K. [Lawrence Livermore National Lab., CA (United States); Vincitore, A.M.; Senka, S.M. [Univ. of California, Los Angeles, CA (United States); Lutz, A.E. [Sandia National Labs., Livermore, CA (United States)

    1998-01-01

    The chemical structure of an opposed flow, methane diffusion flame is studied using a chemical kinetic model and the results are compared to experimental measurements. The chemical kinetic paths leading to aromatics and polycyclic aromatics hydrocarbons (PAHs) in the diffusion flame are identified. These paths all involve resonantly stabilized radicals which include propargyl, allyl, cyclopentadienyl, and benzyl radicals. The modeling results show reasonable agreement with the experimental measurements for the large hydrocarbon aliphatic compounds, aromatics, and PAHs. the benzene was predicted to be formed primarily by the reaction sequence of Allyl plus Propargyl equals Fulvene plus H plus H followed by fulvene isomerization to benzene. Naphthalene was modeled using the reaction of benzyl with propargyl, while the combination of cyclopentadienyl radicals were shown to be a minor contributor in the diffusion flame. The agreement between the model and experiment for the four-ring PAHs was poor.

  9. Amoeba-like motion of an oil droplet. Chemical model of self-motile organisms

    Science.gov (United States)

    Sumino, Y.; Yoshikawa, K.

    2014-06-01

    In this paper, we demonstrate our recent attempt to construct a chemical model system of amoeboid motion. The system is intended to mimic biological motility based on the generation and collapse of an elastic aggregate; it is composed of oil, water, and surfactants. In this chemical system, the oil-water interface shows extension and retreat of spherical extrusions accompanied by the generation of aggregate on the interface. This instability of the oil-water interface can cause autonomous splitting and motion of a floating oil droplet. The current mathematical model based on the generation of a passive elastic gel is explained, as well as the discrepancy between the model and the experiments. We further describe recently observed microscopic characteristics of the aggregate formation process that might cause the interfacial instability. Finally, we discuss the disadvantage of a chemical model system compared with active colloid and in vitro biological systems, and also mention its potential advantages.

  10. The health belief model and consumer information searches: toward an integrated model.

    Science.gov (United States)

    Risker, D C

    1996-01-01

    Some health data organizations (HDOs) are producing consumer-level health services information. National reform proposals would suggest that competition between health plans will be developed through the use of outcome information. Policy makers have paid little attention to how consumers might use that information or how that information might be most effectively packaged for consumer use. This paper argues that marketing literature developed over the last ten to fifteen years could prove to be an informative resource for policy makers and the health services provider community alike. This paper suggests that combining a consumer decision model (CDM) with the health belief model (HBM) will provide an important step toward an increased understanding of consumer information search behavior. This integrated model could form the basis of future research in this important area.

  11. Lamb wave propagation modeling for structure health monitoring

    Institute of Scientific and Technical Information of China (English)

    Xiaoyue ZHANG; Shenfang YUAN; Tong HAO

    2009-01-01

    This study aims to model the propagation of Lamb waves used in structure health monitoring. A number of different numerical computational techniques have been developed for wave propagation studies. The local interaction simulation approach, used for modeling sharp interfaces and discontinuities in complex media (LISA/SIM theory), has been effectively applied to numerical simulations of elastic wave interaction. This modeling is based on the local interaction simulation approach theory and is finally accomplished through the finite elements software Ansys11. In this paper, the Lamb waves propagating characteristics and the LISA/SIM theory are introduced. The finite difference equations describing wave propagation used in the LISA/SIM theory are obtained. Then, an anisotropic metallic plate model is modeled and a simulating Lamb waves signal is loaded on. Finally, the Lamb waves propagation modeling is implemented.

  12. On modeling of the evaporation of chemical warfare agents on the ground

    NARCIS (Netherlands)

    Westin, S.N.; Winter, S.; Karlsson, E.; Hin, A.; Oeseburg, F.

    1998-01-01

    A model for evaporation of chemical warfare agents on the ground has been developed. The process of evaporation is described in three steps: (1) the immediate drop enlargement due to impact momentum is modeled using an empirical correlation from technical literature; (2) further enlargement caused b

  13. Modelling of the Absorption and Desorption Process of Chemical Heat Pumps

    Institute of Scientific and Technical Information of China (English)

    Gui-PingLin; Xiu-GanYuan

    1993-01-01

    A simple model for the desorption and absorption process of the chemical heat pump is presented in this paper .It is based on the assumption of a definite reaction front.The results from this model are compared with those obtained by finite difference method and it is observed that there is almost no difference between them.

  14. Building a model based on scientific consensus for Life Cycle Impact Assessment of chemicals:

    DEFF Research Database (Denmark)

    Hauschild, Michael Zwicky; Huijbregts, Mark; Jolliet, Olivier

    2008-01-01

    Achieving consensus among scientists is often a challenge - particularly in model development. In this article we describe a recent scientific consensus-building process for Life Cycle Impact Assessment (LCIA) models applied to chemical emissions - including the strategy, execution, and results...

  15. Medicinal plants recommended by the world health organization: DNA barcode identification associated with chemical analyses guarantees their quality.

    Directory of Open Access Journals (Sweden)

    Rafael Melo Palhares

    Full Text Available Medicinal plants are used throughout the world, and the regulations defining their proper use, such as identification of the correct species and verification of the presence, purity and concentration of the required chemical compounds, are widely recognized. Herbal medicines are made from vegetal drugs, the processed products of medicinal species. These processed materials present a number of challenges in terms of botanical identification, and according to the World Health Organization (WHO, the use of incorrect species is a threat to consumer safety. The samples used in this study consisted of the dried leaves, flowers and roots of 257 samples from 8 distinct species approved by the WHO for the production of medicinal herbs and sold in Brazilian markets. Identification of the samples in this study using DNA barcoding (matK, rbcL and ITS2 regions revealed that the level of substitutions may be as high as 71%. Using qualitative and quantitative chemical analyses, this study identified situations in which the correct species was being sold, but the chemical compounds were not present. Even more troubling, some samples identified as substitutions using DNA barcoding contained the chemical compounds from the correct species at the minimum required concentration. This last situation may lead to the use of unknown species or species whose safety for human consumption remains unknown. This study concludes that DNA barcoding should be used in a complementary manner for species identification with chemical analyses to detect and quantify the required chemical compounds, thus improving the quality of this class of medicines.

  16. Conservation equations and physical models for hypersonic air flows in thermal and chemical nonequilibrium

    Science.gov (United States)

    Gnoffo, Peter A.; Gupta, Roop N.; Shinn, Judy L.

    1989-01-01

    The conservation equations for simulating hypersonic flows in thermal and chemical nonequilibrium and details of the associated physical models are presented. These details include the curve fits used for defining thermodynamic properties of the 11 species air model, curve fits for collision cross sections, expressions for transport properties, the chemical kinetics models, and the vibrational and electronic energy relaxation models. The expressions are formulated in the context of either a two or three temperature model. Greater emphasis is placed on the two temperature model in which it is assumed that the translational and rotational energy models are in equilibrium at the translational temperature, T, and the vibrational, electronic, and electron translational energy modes are in equilibrium at the vibrational temperature, T sub v. The eigenvalues and eigenvectors associated with the Jacobian of the flux vector are also presented in order to accommodate the upwind based numerical solutions of the complete equation set.

  17. Linear Sigma Model at Finite Temperature and Baryonic Chemical Potential Using the N-Midpoint Technique

    Directory of Open Access Journals (Sweden)

    M. Abu-Shady

    2014-01-01

    Full Text Available A baryonic chemical potential (μb is included in the linear sigma model at finite temperature. The effective mesonic potential is numerically calculated using the N-midpoint rule. The meson masses are investigated as functions of the temperature (T at fixed value of baryonic chemical potential. The pressure and energy density are investigated as functions of temperature at fi…xed value of μb. The obtained results are in good agreement in comparison with other techniques. We conclude that the calculated effective potential successfully predicts the meson properties and thermodynamic properties at finite baryonic chemical potential.

  18. Modeling of thermodynamic and chemical changes in low-temperature geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, A.L.

    1986-12-01

    A method was developed to incorporate the transport of several chemical components into a model of the transport of fluid mass and heat within a geothermal system. It was demonstrated that the use of coupled hydrological, thermal and chemical data allows for the determination of field porosities, amounts and regions of cool recharge into the system as well as field permeabilities and the hot reservoir volume. With the additional information a reliable prediction of the long-term cooling rate can be made.

  19. Multi-pathway exposure modelling of chemicals in cosmetics with application to shampoo

    DEFF Research Database (Denmark)

    Ernstoff, Alexi S.; Fantke, Peter; Csiszar, Susan A.

    2016-01-01

    We present a novel multi-pathway, mass balance based, fate and exposure model compatible with life cycle and high-throughput screening assessments of chemicals in cosmetic products. The exposures through product use as well as post-use emissions and environmental media were quantified based...... and critical advancement for life cycle assessments and high-throughput exposure screening of chemicals in cosmetic products demonstrating the importance of consistent consideration of near- and far-field multi-pathway exposures....

  20. Acid-Base Chemistry of White Wine: Analytical Characterisation and Chemical Modelling

    OpenAIRE

    Enrico Prenesti; Silvia Berto; Simona Toso; Pier Giuseppe Daniele

    2012-01-01

    A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria). Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of car...

  1. Predictive models for the assessment of occupational exposure to chemicals: A new challenge for employers

    OpenAIRE

    Jan Piotr Gromiec; Małgorzata Kupczewska-Dobecka; Agnieszka Jankowska; Sławomir Czerczak

    2013-01-01

    Employers are obliged to carry out and document the risk associated with the use of chemical substances. The best but the most expensive method is to measure workplace concentrations of chemicals. At present no "measureless" method for risk assessment is available in Poland, but predictive models for such assessments have been developed in some countries. The purpose of this work is to review and evaluate the applicability of selected predictive methods for assessing occupational inhalation e...

  2. Phase Characterization of Cucumber Growth: A Chemical Gel Model

    Directory of Open Access Journals (Sweden)

    Bo Li

    2016-01-01

    Full Text Available Cucumber grows with complex phenomena by changing its volume and shape, which is not fully investigated and challenges agriculture and food safety industry. In order to understand the mechanism and to characterize the growth process, the cucumber is modeled as a hydrogel in swelling and its development is studied in both preharvest and postharvest stages. Based on thermodynamics, constitutive equations, incorporating biological quantities, are established. The growth behavior of cucumber follows the classic theory of continuous or discontinuous phase transition. The mechanism of bulged tail in cucumber is interpreted by phase coexistence and characterized by critical conditions. Conclusions are given for advances in food engineering and novel fabrication techniques in mechanical biology.

  3. Modelling system level health information exchange: an ontological approach.

    Science.gov (United States)

    McMurray, J; Zhu, L; McKillop, I; Chen, H

    2015-01-01

    Investment of resources to purposively improve the movement of information between health system providers is currently made with imperfect information. No inventories of system-level digital information flows currently exist, nor do measures of inter-organizational electronic information. exchange (HIE). Using Protégé 4, an open-source OWL Web ontology language editor and knowledge-based framework we formalized a model that decomposes inter-organizational electronic health information flow into derivative concepts such as diversity, breadth, volume, structure, standardization and connectivity. Self-reported data from a regional health system is used to measure HIE; the ontology identifies providers with low and high HIE, useful for planners, and using a related database is used to monitor data quality.

  4. Towards an Integrated Model of Earth's Thermo-Chemical Evolution and Plate Tectonics

    Science.gov (United States)

    Tackley, P. J.; Xie, S.

    2001-05-01

    It has long been a challenge for geodynamicists, who have typically modeled homogeneous mantles, to explain the geochemical evidence for the existence of several distinct chemical reservoirs, in terms of a dynamically and chemically self-consistent model. While the mixing behavior of generalized tracers has received much attention in the modeling community, a recent trend has been towards mantle convection models that track the evolution of specific chemical species, both major and minor, and can thus be related to geochemical observations. However, obtaining realistic chemical evolution in such models is dependent on their having a reasonable representation of plate tectonic behavior since the recycling of oceanic crust and complementary depleted residuum is a key process in Earth that other terrestrial planets may lack. In general, this has required inserting plate motions by hand in models. In recent years, however, we have learned how to perform numerical simulations of mantle convection in which plate tectonic behavior is introduced self-consistently through plastic yielding of the lithosphere. In this presentation, models of mantle convection that combine a treatment of geochemical evolution with self-consistently generated plate tectonics, will be presented. Preliminary results indicate that the system can self-consistently evolve regions which have a HIMU-like signature as well as regions with a high He3/He4 ratio.

  5. A coupled physical-biological-chemical model for the Indian Ocean

    Indian Academy of Sciences (India)

    P S Swathi; M K Sharada; K S Yajnik

    2000-12-01

    A coupled physical-biological-chemical model has been developed at C-MMACS. for studying the time- variation of primary productivity and air-sea carbon-dioxide exchange in the Indian Ocean. The physical model is based on the Modular Ocean Model, Version 2 (MOM2) and the biological model describes the nonlinear dynamics of a 7-component marine ecosystem. The chemical model includes dynamical equation for the evolution of dissolved inorganic carbon and total alkalinity. The interaction between the biological and chemical model is through the Redfield ratio. The partial pressure of carbon dioxide pCO2 of the surface layer is obtained from the chemical equilibrium equations of Peng et al 1987. Transfer coefficients for air-sea exchange of CO2 are computed dynamically based on the wind speeds. The coupled model reproduces the high productivity observed in the Arabian Sea off the Somali and Omani coasts during the Southwest (SW) monsoon. The entire Arabian Sea is an outgassing region for CO2 in spite of high productivity with transfer rates as high as 80 m-mol C/m2/day during SW monsoon near the Somali Coast on account of strong winds.

  6. Managing the health of the elite athlete: a new integrated performance health management and coaching model

    Science.gov (United States)

    Dijkstra, H Paul; Pollock, N; Chakraverty, R; Alonso, J M

    2014-01-01

    Elite athletes endeavour to train and compete even when ill or injured. Their motivation may be intrinsic or due to coach and team pressures. The sports medicine physician plays an important role to risk-manage the health of the competing athlete in partnership with the coach and other members of the support team. The sports medicine physician needs to strike the right ethical and operational balance between health management and optimising performance. It is necessary to revisit the popular delivery model of sports medicine and science services to elite athletes based on the current reductionist multispecialist system lacking in practice an integrated approach and effective communication. Athlete and coach in isolation or with a member of the multidisciplinary support team, often not qualified or experienced to do so, decide on the utilisation of services and how to apply the recommendations. We propose a new Integrated Performance Health Management and Coaching model based on the UK Athletics experience in preparation for the London Olympic and Paralympic Games. The Medical and Coaching Teams are managed by qualified and experienced individuals operating in synergy towards a common performance goal, accountable to a Performance Director and ultimately to the Board of Directors. We describe the systems, processes and implementation strategies to assist the athlete, coach and support teams to continuously monitor and manage athlete health and performance. These systems facilitate a balanced approach to training and competing decisions, especially while the athlete is ill or injured. They take into account the best medical advice and athlete preference. This Integrated Performance Health Management and Coaching model underpinned the Track and Field Gold Medal performances at the London Olympic and Paralympic Games. PMID:24620040

  7. Managing the health of the elite athlete: a new integrated performance health management and coaching model.

    Science.gov (United States)

    Dijkstra, H Paul; Pollock, N; Chakraverty, R; Alonso, J M

    2014-04-01

    Elite athletes endeavour to train and compete even when ill or injured. Their motivation may be intrinsic or due to coach and team pressures. The sports medicine physician plays an important role to risk-manage the health of the competing athlete in partnership with the coach and other members of the support team. The sports medicine physician needs to strike the right ethical and operational balance between health management and optimising performance. It is necessary to revisit the popular delivery model of sports medicine and science services to elite athletes based on the current reductionist multispecialist system lacking in practice an integrated approach and effective communication. Athlete and coach in isolation or with a member of the multidisciplinary support team, often not qualified or experienced to do so, decide on the utilisation of services and how to apply the recommendations. We propose a new Integrated Performance Health Management and Coaching model based on the UK Athletics experience in preparation for the London Olympic and Paralympic Games. The Medical and Coaching Teams are managed by qualified and experienced individuals operating in synergy towards a common performance goal, accountable to a Performance Director and ultimately to the Board of Directors. We describe the systems, processes and implementation strategies to assist the athlete, coach and support teams to continuously monitor and manage athlete health and performance. These systems facilitate a balanced approach to training and competing decisions, especially while the athlete is ill or injured. They take into account the best medical advice and athlete preference. This Integrated Performance Health Management and Coaching model underpinned the Track and Field Gold Medal performances at the London Olympic and Paralympic Games.

  8. Requirements model for an e-Health awareness portal

    Science.gov (United States)

    Hussain, Azham; Mkpojiogu, Emmanuel O. C.; Nawi, Mohd Nasrun M.

    2016-08-01

    Requirements engineering is at the heart and foundation of software engineering process. Poor quality requirements inevitably lead to poor quality software solutions. Also, poor requirement modeling is tantamount to designing a poor quality product. So, quality assured requirements development collaborates fine with usable products in giving the software product the needed quality it demands. In the light of the foregoing, the requirements for an e-Ebola Awareness Portal were modeled with a good attention given to these software engineering concerns. The requirements for the e-Health Awareness Portal are modeled as a contribution to the fight against Ebola and helps in the fulfillment of the United Nation's Millennium Development Goal No. 6. In this study requirements were modeled using UML 2.0 modeling technique.

  9. Transferring Chemical Research to a Spin-Off Initiative in Health Care: The Lipidomic Approach

    Science.gov (United States)

    Ferreri, Carla; Chatgilialoglu, Chryssostomos; Ferreri, Rosaria

    2008-01-01

    Lipidomics is an emerging discipline in life sciences related to the lipid metabolism of living organisms. In the last decade chemical and biological research has attributed very important roles to membrane phospholipids in relationship to free radical stress and metabolic situations. An entrepreneurial initiative for diagnostic tools and health…

  10. 75 FR 29754 - Claims of Confidentiality of Certain Chemical Identities Contained in Health and Safety Studies...

    Science.gov (United States)

    2010-05-27

    ... comment that is placed in the docket and made available on the Internet. If you submit an electronic... difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic... by oxidizing methanol. In contrast, the names of some chemical substances -- especially polymers...

  11. The Developing Brain: A Largely Overlooked Health Endpoint in Risk Assessments for Synthetic Chemical Substances

    Science.gov (United States)

    McElgunn, Barbara

    2010-01-01

    A large body of experimental animal research on the neurotoxic effects of certain environmental chemicals provides evidence of a cascade of neurobehavioural effects including learning deficits, hyperactivity, anxiety, depression, lack of motivation, increased aggressiveness, altered maternal care and bonding, and an over-reaction to small…

  12. Access and use of information resources in assessing health risks from chemicals in food

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, W.A. [Department of Agriculture, Beltsville, MD (United States)

    1990-12-31

    The Food Safety and Inspection Service (FSIS) is responsible for the wholesomeness, safety, and adulteration-free status of meat and poultry. The agency developed the National Residue Program (NRP) to monitor these products for residue of drugs, pesticides, and environmental contaminants. Today, few chemical residues are detected in meat and poultry because of the success of the NRP. 3 figs.

  13. The Relationship between Odour Annoyance Scores and Modelled Ambient Air Pollution in Sarnia, “Chemical Valley”, Ontario

    Directory of Open Access Journals (Sweden)

    Dominic Odwa Atari

    2009-10-01

    Full Text Available This study aimed at establishing the relationship between annoyance scores and modelled air pollution in “Chemical Valley”, Sarnia, Ontario (Canada. Annoyance scores were taken from a community health survey (N = 774; and respondents’ exposure to nitrogen dioxide (NO2 and sulphur dioxide (SO2 were estimated using land use regression (LUR models. The associations were examined by univariate analysis while multivariate logistic regression was used to examine the determinants of odour annoyance. The results showed that odour annoyance was significantly correlated to modelled pollutants at the individual (NO2, r = 0.15; SO2, r = 0.13 and census tract (NO2, r = 0.56; SO2, r = 0.67 levels. The exposure-response relationships show that residents of Sarnia react to very low pollution concentrations levels even if they are within the Ontario ambient air quality criteria. The study found that exposure to high NO2 and SO2 concentrations, gender, and perception of health effects were significant determinants of individual odour annoyance reporting. The observed association between odour annoyance and modelled ambient pollution suggest that individual and census tract level annoyance scores may serve as proxies for air quality in exposed communities because they capture the within area spatial variability of pollution. However, questionnaire-based odour annoyance scores need to be validated longitudinally and across different scales if they are to be adopted for use at the national level.

  14. Zebrafish as a model system for environmental health studies in the grade 9-12 classroom.

    Science.gov (United States)

    Tomasiewicz, Henry G; Hesselbach, Renee; Carvan, Michael John; Goldberg, Barbara; Berg, Craig A; Petering, David H

    2014-08-01

    Developing zebrafish embryos were used as a model system for high school students to conduct scientific investigations that reveal features of normal development and to test how different environmental toxicants impact the developmental process. The primary goal of the module was to engage students from a wide range of socio-economic backgrounds, with particular focus on underserved inner-city high schools, in inquiry-based learning and hands-on experimentation. In addition, the module served as a platform for both teachers and students to design additional inquiry-based experiments. In this module, students spawned adult zebrafish to generate developing embryos, exposed the embryos to various toxicants, then gathered, and analyzed data obtained from control and experimental embryos. The module provided a flexible, experimental framework for students to test the effects of numerous environmental toxicants, such as ethanol, caffeine, and nicotine, on the development of a model vertebrate organism. Students also observed the effects of dose on experimental outcomes. From observations of the effects of the chemical agents on vertebrate embryos, students drew conclusions on how these chemicals could impact human development and health. Results of pre-tests and post-tests completed by participating students indicate statistically significant changes in awareness of the impact of environmental agents on fish and human beings In addition, the program's evaluator concluded that participation in the module resulted in significant changes in the attitude of students and teachers toward science in general and environmental health in particular.

  15. Multi-pathway exposure modeling of chemicals in cosmetics with application to shampoo.

    Science.gov (United States)

    Ernstoff, Alexi S; Fantke, Peter; Csiszar, Susan A; Henderson, Andrew D; Chung, Susie; Jolliet, Olivier

    2016-01-01

    We present a novel multi-pathway, mass balance based, fate and exposure model compatible with life cycle and high-throughput screening assessments of chemicals in cosmetic products. The exposures through product use as well as post-use emissions and environmental media were quantified based on the chemical mass originally applied via a product, multiplied by the product intake fractions (PiF, the fraction of a chemical in a product that is taken in by exposed persons) to yield intake rates. The average PiFs for the evaluated chemicals in shampoo ranged from 3×10(-4) up to 0.3 for rapidly absorbed ingredients. Average intake rates ranged between nano- and micrograms per kilogram bodyweight per day; the order of chemical prioritization was strongly affected by the ingredient concentration in shampoo. Dermal intake and inhalation (for 20% of the evaluated chemicals) during use dominated exposure, while the skin permeation coefficient dominated the estimated uncertainties. The fraction of chemical taken in by a shampoo user often exceeded, by orders of magnitude, the aggregated fraction taken in by the population through post-use environmental emissions. Chemicals with relatively high octanol-water partitioning and/or volatility, and low molecular weight tended to have higher use stage exposure. Chemicals with low intakes during use (<1%) and subsequent high post-use emissions, however, may yield comparable intake for a member of the general population. The presented PiF based framework offers a novel and critical advancement for life cycle assessments and high-throughput exposure screening of chemicals in cosmetic products demonstrating the importance of consistent consideration of near- and far-field multi-pathway exposures.

  16. Mineral Bionization - Surface Chemical Modeling of the Emergence of Life

    Science.gov (United States)

    Arrhenius, G.

    2001-12-01

    The earliest stages in entering an RNA-world require natural mechanisms that are capable of selective concentration of simple aldehydes from dilute solution in the environment (4), furthermore phosphorylation of the sequestered aldehydes (2) and their catalytic condensation to form, selectively, tetrose- (threose) or pentose- (ribose) phosphate (3); the latter representing the R in RNA. A variety of common positively charged sheet structure minerals (mixed valence double layer metal hydroxide minerals such as hydrotalcite and green rust) have proven to be remarkably capable of performing these crucial tasks under simplified natural conditions (1). These prebiotic model reactions have demonstrated plausible closure of the gap, previously thought to preclude the natural formation of nucleoside phosphates, the backbone components of the information carrying genetic material. Pioneering research by other workers (5) has demonstrated the feasibility of necessary further steps in the chain toward functional RNA; mineral (montmorillonite) catalyzed oligomerization of nucleotides, the formation of complementary RNA strands (6) and the enzymatic activity of RNA (ribozymes). These contributions have placed the initially conjectural concept of an initial RNA-world on an experimental footing. Remaining problems include the initial transfer of information to spontaneously forming RNA, sufficient to convey biofunctionallity (7). Also in this central problem mineral surface interactions may be speculated to play a natural role; a question that is open to experimental verification. References. 1. Pitsch, S.; Eschenmoser, A.; Gedulin, B.; Hui, S. and Arrhenius, G. Origins Life Evol. Biosphere, 1994, 24 (5), 389. 2. Kolb, V.; Zhang, S.; Xu, Y.; Arrhenius, G. Origins Life Evol. Biosphere, 1997, 27, 485. 3. Krishnamurthy, R.; Pitsch, S.; Arrhenius, G. Origins Life Evol. Biosphere, Origins Life Evol. Biosphere 1999, 29, 139 4. Pitsch, S.; Krishnamurthy, R.; Arrhenius, G. Helv. Chim

  17. Description and evaluation of the Model for Ozone and Related chemical Tracers, version 4 (MOZART-4

    Directory of Open Access Journals (Sweden)

    L. K. Emmons

    2010-01-01

    Full Text Available The Model for Ozone and Related chemical Tracers, version 4 (MOZART-4 is an offline global chemical transport model particularly suited for studies of the troposphere. The updates of the model from its previous version MOZART-2 are described, including an expansion of the chemical mechanism to include more detailed hydrocarbon chemistry and bulk aerosols. Online calculations of a number of processes, such as dry deposition, emissions of isoprene and monoterpenes and photolysis frequencies, are now included. Results from an eight-year simulation (2000–2007 are presented and evaluated. The MOZART-4 source code and standard input files are available for download from the NCAR Community Data Portal (http://cdp.ucar.edu.

  18. Development and Analysis of Group Contribution Plus Models for Property Prediction of Organic Chemical Systems

    DEFF Research Database (Denmark)

    Mustaffa, Azizul Azri

    Prediction of properties is important in chemical process-product design. Reliable property models are needed for increasingly complex and wider range of chemicals. Group-contribution methods provide useful tool but there is a need to validate them and improve their accuracy when complex chemicals...... are present in the mixtures. In accordance with that, a combined group-contribution and atom connectivity approach that is able to extend the application range of property models has been developed for mixture properties. This so-called Group-ContributionPlus (GCPlus) approach is a hybrid model which combines...... group contribution and molecular descriptor theories (such as connectivity indices – CI). Connectivity indices are formalisms defined via graph theoretical concepts intended to describe the topological characteristics of molecular structures. The main idea is the use of connectivity indices to describe...

  19. Reduced-form modeling of public health impacts of inorganic PM2.5 and precursor emissions

    Science.gov (United States)

    Heo, Jinhyok; Adams, Peter J.; Gao, H. Oliver

    2016-07-01

    It is challenging to estimate the public health costs of fine particulate matter (PM2.5) and its precursor emissions accurately and quickly for policy research because of their complex physical and chemical processes occurring over a large downwind area. We developed a method for building statistical regressions that estimate public health cost of emissions accurately like a state-of-the-art chemical transport model (CTM) but without its high computational cost. This method achieves detailed spatial resolution according to the location of the emission source, accounting for differences in the exposed population downwind. Using tagged CTM simulations, our method builds a large dataset of air quality public health costs from marginal emissions throughout the United States. Two methods were developed to describe exposed population, one that assumes a generic downwind plume concentration profile derived from CTM outputs and a simpler method that uses the size of population within certain distances as variables. Using the former method, we parameterized marginal public health cost [/t] and intake fraction [ppm] as a function of exposed population and key atmospheric variables. We derived models for elemental carbon, sulfur dioxide, nitrogen oxides, and ammonia. Compared to estimates calculated directly using CTM outputs, our models generally show mean fractional errors of only 10%-30% and up to 50% for NOx in some seasons, which are generally similar to or less than CTM's performance. Our results show that the public health costs of emissions can be efficiently parameterized for policy analyses based on state-of-the-art CTMs.

  20. Health-aware Model Predictive Control of Pasteurization Plant

    Science.gov (United States)

    Karimi Pour, Fatemeh; Puig, Vicenç; Ocampo-Martinez, Carlos

    2017-01-01

    In order to optimize the trade-off between components life and energy consumption, the integration of a system health management and control modules is required. This paper proposes the integration of model predictive control (MPC) with a fatigue estimation approach that minimizes the damage of the components of a pasteurization plant. The fatigue estimation is assessed with the rainflow counting algorithm. Using data from this algorithm, a simplified model that characterizes the health of the system is developed and integrated with MPC. The MPC controller objective is modified by adding an extra criterion that takes into account the accumulated damage. But, a steady-state offset is created by adding this extra criterion. Finally, by including an integral action in the MPC controller, the steady-state error for regulation purpose is eliminated. The proposed control scheme is validated in simulation using a simulator of a utility-scale pasteurization plant.

  1. Constructing and visualizing chemical reaction networks from pi-calculus models

    OpenAIRE

    M. John; H.-J. Schulz; H. Schumann; A. M. Uhrmacher; Andrea Unger

    2013-01-01

    International audience; The pi-calculus, in particular its stochastic version the stochastic pi-calculus, is a common modeling formalism to concisely describe the chemical reactions occurring in biochemical systems. However, it remains largely unexplored how to transform a biochemical model expressed in the stochastic pi-calculus back into a set of meaningful reactions. To this end, we present a two step approach of first translating model states to reaction sets and then visualizing sequence...

  2. An integrated fluid-chemical model towards modeling the formation of intra-luminal thrombus in abdominal aortic aneurysms

    Directory of Open Access Journals (Sweden)

    Jacopo eBiasetti

    2012-07-01

    Full Text Available Abdominal Aortic Aneurysms (AAAs are frequently characterized by the presenceof an Intra-Luminal Thrombus (ILT known to influence biochemically and biomechanicallytheir evolution. ILT progression mechanism is still unclear and little is known regardingthe impact on this mechanism of the chemical species transported by blood flow.Chemical agonists and antagonists of platelets activation, aggregation, and adhesion andthe proteins involved in the coagulation cascade (CC may play an important role in ILTdevelopment. Starting from this assumption, the evolution of chemical species involvedin the CC, their relation to coherent vortical structures (VSs and their possible effect onILT evolution have been studied. To this end a fluido-chemical model that simulates theCC through a series of convection-diffusion-reaction (CDR equations has been developed.The model involves plasma-phase and surface bound enzymes and zymogens, and includesboth plasma-phase and membrane-phase reactions. Blood is modeled as a non-Newtonianincompressible fluid. VSs convect thrombin in the domain and lead to the high concentration observed in the distal portion of the AAA. This finding is in line with the clinicalobservations showing that the thickest ILT is usually seen in the distal AAA region. Theproposed model, due to its ability to couple the fluid and chemical domains, provides anintegrated mechanochemical picture that potentially could help unveil mechanisms of ILTformation and development.

  3. A priori modeling of chemical reactions on computational grid platforms: Workflows and data models

    Energy Technology Data Exchange (ETDEWEB)

    Rampino, S., E-mail: ser_ram@dyn.unipg.it [Dipartimento di Chimica, Universita degli Studi di Perugia, Via Elce di Sotto 8, 06123 Perugia (Italy); Monari, A. [SRSMC-Equipe de Chimie et Biochimie Theoriques, Nancy-Universite et CNRS, Bp70239 Boulevard des Aiguilettes, 54506 Vandoeuvre-les-Nancy Cedex (France); Rossi, E. [CINECA, Via Manganelli 6/3, 40033 Casalecchio di Reno, Bologna (Italy); Evangelisti, S. [Laboratoire de Chimie et de Physique Quantiques, Universite Paul Sabatier Toulouse III et CNRS, 118 Route de Narbonne, 31062 Toulouse Cedex 4 (France); Lagana, A. [Dipartimento di Chimica, Universita degli Studi di Perugia, Via Elce di Sotto 8, 06123 Perugia (Italy)

    2012-04-04

    Graphical abstract: The quantum framework of the Grid Empowered Molecular Simulator GEMS assembled on the European Grid allows the ab initio evaluation of the dynamics of small systems starting from the calculation of the electronic properties. Highlights: Black-Right-Pointing-Pointer The grid based GEMS simulator accurately models small chemical systems. Black-Right-Pointing-Pointer Q5Cost and D5Cost file formats provide interoperability in the workflow. Black-Right-Pointing-Pointer Benchmark runs on H + H{sub 2} highlight the Grid empowering. Black-Right-Pointing-Pointer O + O{sub 2} and N + N{sub 2} calculated k (T)'s fall within the error bars of the experiment. - Abstract: The quantum framework of the Grid Empowered Molecular Simulator GEMS has been assembled on the segment of the European Grid devoted to the Computational Chemistry Virtual Organization. The related grid based workflow allows the ab initio evaluation of the dynamics of small systems starting from the calculation of the electronic properties. Interoperability between computational codes across the different stages of the workflow was made possible by the use of the common data formats Q5Cost and D5Cost. Illustrative benchmark runs have been performed on the prototype H + H{sub 2}, N + N{sub 2} and O + O{sub 2} gas phase exchange reactions and thermal rate coefficients have been calculated for the last two. Results are discussed in terms of the modeling of the interaction and advantages of using the Grid is highlighted.

  4. Photochemical modeling in California with two chemical mechanisms: model intercomparison and response to emission reductions.

    Science.gov (United States)

    Cai, Chenxia; Kelly, James T; Avise, Jeremy C; Kaduwela, Ajith P; Stockwell, William R

    2011-05-01

    An updated version of the Statewide Air Pollution Research Center (SAPRC) chemical mechanism (SAPRC07C) was implemented into the Community Multiscale Air Quality (CMAQ) version 4.6. CMAQ simulations using SAPRC07C and the previously released version, SAPRC99, were performed and compared for an episode during July-August, 2000. Ozone (O3) predictions of the SAPRC07C simulation are generally lower than those of the SAPRC99 simulation in the key areas of central and southern California, especially in areas where modeled concentrations are greater than the federal 8-hr O3 standard of 75 parts per billion (ppb) and/or when the volatile organic compound (VOC)/nitrogen oxides (NOx) ratio is less than 13. The relative changes of ozone production efficiency (OPE) against the VOC/NOx ratio at 46 sites indicate that the OPE is reduced in SAPRC07C compared with SAPRC99 at most sites by as much as approximately 22%. The SAPRC99 and SAPRC07C mechanisms respond similarly to 20% reductions in anthropogenic VOC emissions. The response of the mechanisms to 20% NOx emissions reductions can be grouped into three cases. In case 1, in which both mechanisms show a decrease in daily maximum 8-hr O3 concentration with decreasing NOx emissions, the O3 decrease in SAPRC07C is smaller. In case 2, in which both mechanisms show an increase in O3 with decreasing NOx emissions, the O3 increase is larger in SAPRC07C. In case 3, SAPRC07C simulates an increase in O3 in response to reduced NOx emissions whereas SAPRC99 simulates a decrease in O3 for the same region. As a result, the areas where NOx controls would be disbeneficial are spatially expanded in SAPRC07C. Although the results presented here are valuable for understanding differences in predictions and model response for SAPRC99 and SAPRC07C, the study did not evaluate the impact of mechanism differences in the context of the U.S. Environmental Protection Agency's guidance for using numerical models in demonstrating air quality attainment

  5. Predictive Toxicology: Modeling Chemical Induced Toxicological Response Combining Circular Fingerprints with Random Forest and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Alexios eKoutsoukas

    2016-03-01

    Full Text Available Modern drug discovery and toxicological research are under pressure, as the cost of developing and testing new chemicals for potential toxicological risk is rising. Extensive evaluation of chemical products for potential adverse effects is a challenging task, due to the large number of chemicals and the possible hazardous effects on human health. Safety regulatory agencies around the world are dealing with two major challenges. First, the growth of chemicals introduced every year in household products and medicines that need to be tested, and second the need to protect public welfare. Hence, alternative and more efficient toxicological risk assessment methods are in high demand. The Toxicology in the 21st Century (Tox21 consortium a collaborative effort was formed to develop and investigate alternative assessment methods. A collection of 10,000 compounds composed of environmental chemicals and approved drugs were screened for interference in biochemical pathways and released for crowdsourcing data analysis. The physicochemical space covered by Tox21 library was explored, measured by Molecular Weight (MW and the octanol/water partition coefficient (cLogP. It was found that on average chemical structures had MW of 272.6 Daltons. In case of cLogP the average value was 2.476. Next relationships between assays were examined based on compounds activity profiles across the assays utilizing the Pearson correlation coefficient r. A cluster was observed between the Androgen and Estrogen Receptors and their ligand bind domains accordingly indicating presence of cross talks among the receptors. The highest correlations observed were between NR.AR and NR.AR_LBD, where it was r=0.66 and between NR.ER and NR.ER_LBD, where it was r=0.5.Our approach to model the Tox21 data consisted of utilizing circular molecular fingerprints combined with Random Forest and Support Vector Machine by modeling each assay independently. In all of the 12 sub-challenges our modeling

  6. A model for 'reverse innovation' in health care.

    Science.gov (United States)

    Depasse, Jacqueline W; Lee, Patrick T

    2013-08-30

    'Reverse innovation,' a principle well established in the business world, describes the flow of ideas from emerging to more developed economies. There is strong and growing interest in applying this concept to health care, yet there is currently no framework for describing the stages of reverse innovation or identifying opportunities to accelerate the development process. This paper combines the business concept of reverse innovation with diffusion of innovation theory to propose a model for reverse innovation as a way to innovate in health care. Our model includes the following steps: (1) identifying a problem common to lower- and higher-income countries; (2) innovation and spread in the low-income country (LIC); (3) crossover to the higher-income country (HIC); and (4) innovation and spread in the HIC. The crucial populations in this pathway, drawing from diffusion of innovation theory, are LIC innovators, LIC early adopters, and HIC innovators. We illustrate the model with three examples of current reverse innovations. We then propose four sets of specific actions that forward-looking policymakers, entrepreneurs, health system leaders, and researchers may take to accelerate the movement of promising solutions through the reverse innovation pipeline: (1) identify high-priority problems shared by HICs and LICs; (2) create slack for change, especially for LIC innovators, LIC early adopters, and HIC innovators; (3) create spannable social distances between LIC early adopters and HIC innovators; and (4) measure reverse innovation activity globally.

  7. Theory and model use in social marketing health interventions.

    Science.gov (United States)

    Luca, Nadina Raluca; Suggs, L Suzanne

    2013-01-01

    The existing literature suggests that theories and models can serve as valuable frameworks for the design and evaluation of health interventions. However, evidence on the use of theories and models in social marketing interventions is sparse. The purpose of this systematic review is to identify to what extent papers about social marketing health interventions report using theory, which theories are most commonly used, and how theory was used. A systematic search was conducted for articles that reported social marketing interventions for the prevention or management of cancer, diabetes, heart disease, HIV, STDs, and tobacco use, and behaviors related to reproductive health, physical activity, nutrition, and smoking cessation. Articles were published in English, after 1990, reported an evaluation, and met the 6 social marketing benchmarks criteria (behavior change, consumer research, segmentation and targeting, exchange, competition and marketing mix). Twenty-four articles, describing 17 interventions, met the inclusion criteria. Of these 17 interventions, 8 reported using theory and 7 stated how it was used. The transtheoretical model/stages of change was used more often than other theories. Findings highlight an ongoing lack of use or underreporting of the use of theory in social marketing campaigns and reinforce the call to action for applying and reporting theory to guide and evaluate interventions.

  8. Developing a Total Quality Management Model for Health Care Systems

    Directory of Open Access Journals (Sweden)

    AM Mosadegh Rad

    2005-10-01

    Full Text Available Background: Total quality management (TQM is a managerial practice to improve the effectiveness, efficiency, flexibility, and competitiveness of a business as a whole. However, in practice, these TQM benefits are not easy to achieve. Despite its theoretical promise and the enthusiastic response to TQM, recent evidence suggests that attempts to implement it are often unsuccessful. Many of these TQM programmes have been cancelled, or are in the process of being cancelled, as a result of the negative impact on profits. Therefore, there is a pressing need for a clinical approach to establishing TQM. Method: The aim of this article is therefore: “To identify the strengths and weakness of TQM, the logical steps towards TQM, and to develop a model so that health care organizations aiming at using TQM to achieve excellence can follow through easily”. Based on the research questions proposed in this study, the research strategies of a literature review, a questionnaire survey, semi-structured interviews, and a participatory action research were adopted in this study. For determining the success and barriers of TQM in health care organizations, a questionnaire survey has done in 90 health acre organizations in Isfahan Province, which implement TQM. The results of this survey were used for introducing a new model of TQM. This model will be developed via a semi-structured interview with at minimum 10 health care and quality managers. Then, through a participatory action research, this model will be implemented in 3 sites. At this time, the questionnaire survey has done and the model is introduced. Therefore, developing the model and its implementation will be done later. Results: In this survey, the mean score of TQM success was 3.48±0.68 (medium from 5 credits. Implementation of TQM was very low, low, medium, high and very high successful respectively in 3.6, 10.9, 21.8, 56.4 and 7.3 percent of health care organizations. TQM had the most effect on

  9. Determinants of puberty health among female adolescents residing in boarding welfare centers in Tehran: An application of health belief model.

    Science.gov (United States)

    Shirzadi, Shayesteh; Asghari Jafarabadi, Mohammad; Nadrian, Haidar; Mahmoodi, Hassan

    2016-01-01

    Background: Adolescence is a critical stage of growth and development. That is associated with changes in body shape and appearance. Issues such as irregular menstrual periods, amenorrhea, and menstrual cycle are major issues in women's health. The purpose of this study was to examine the determinants of physical puberty health based on the Health Belief Model (HBM) among female adolescents. Methods: This analytical cross sectional study was conducted in welfare boarding centers in Tehran, Iran. Data were collected in 2011 by a structured and valid questionnaire. Total 61 female adolescents (age range: 12-19 yrs) participated in this study from welfare boarding centers in Iran, Tehran, by using convenience sampling method. The questionnaire consisted of demographic characteristics, health belief model constructs and physical puberty health behaviors gathered by using interview. A series of univariate general linear models were used to assess the relationship between puberty health and health belief model constructs. Results: According to the results of this study there were positive significant relationships between perceived susceptibility, perceived benefits, perceived barriers, cues to action and increased puberty health in female adolescents (phealth behaviors. Conclusion: Based on the results of the study to improve the physical Puberty health behaviors of female adolescents should make them aware of the benefits of health behaviors, and remove or reform the perceived barriers of health behaviors. Also, the appropriate information resources should be introduced for obtaining information about puberty health.

  10. The Health Professional as Writer: Two Models for Integrating Writing into the Curricula of Baccalaureate Health Programs.

    Science.gov (United States)

    Haneline, Douglas

    Current changes in health care professions requiring practitioners to have more and better communications skills are necessitating the integration of writing into the health curricula of higher education programs. At Ferris State University, a number of models (in Optometry, Dental Hygiene, Health Systems Management, Nursing, Pharmacy, Medical…

  11. Tests of the higher order turbulence model for atmospheric circulations (HOTMAC) at Deseret Chemical Depot

    Energy Technology Data Exchange (ETDEWEB)

    Costigan, K.R.

    1998-11-01

    Deseret Chemical Depot is one of the US Army`s storage facilities for its stockpile of chemical weapon agents. Congress has directed the Department of Defense to eliminate the aging stockpiles, which have existed since the end of World War II, and the US Army is destroying these lethal chemical munitions. Although the danger is slight, accurate predictions of the wind field in the valley are necessary for dispersion calculations in the event of an accident involving toxic chemicals at the depot. There are several small communities in Rush and Tooele valleys, including the town of Tooele, and Salt Lake City is located 65 km to the Northeast of Deseret Chemical Depot South area, at 1,300 m MSL and beyond the Oquirrh Mountains. The purpose of this report is to carry out three-dimensional numerical simulations of the atmospheric circulations in the region around Deseret Chemical Depot with the Higher Order Turbulence Model for Atmospheric Circulations (HOTMAC) and to evaluate the performance of the model. The code had been modified to assimilate local meteorological observations through the use of Newtonian nudging. The nudging scheme takes advantage of the extensive network of local observations in the valley.

  12. Chemical Compass Model for Avian Magnetoreception as a Quantum Coherent Device

    Science.gov (United States)

    Cai, Jianming; Plenio, Martin B.

    2013-12-01

    It is known that more than 50 species use the Earth’s magnetic field for orientation and navigation. Intensive studies, particularly behavior experiments with birds, provide support for a chemical compass based on magnetically sensitive free radical reactions as a source of this sense. However, the fundamental question of how quantum coherence plays an essential role in such a chemical compass model of avian magnetoreception yet remains controversial. Here, we show that the essence of the chemical compass model can be understood in analogy to a quantum interferometer exploiting global quantum coherence rather than any subsystem coherence. Within the framework of quantum metrology, we quantify global quantum coherence and correlate it with the function of chemical magnetoreception. Our results allow us to understand and predict how various factors can affect the performance of a chemical compass from the unique perspective of quantum coherence assisted metrology. This represents a crucial step to affirm a direct connection between quantum coherence and the function of a chemical compass.

  13. Modelling of associating mixtures for applications in the oil & gas and chemical industries

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios; Folas, Georgios; Muro Sunè, Nuria

    2007-01-01

    -alcohol (glycol)-alkanes and certain acid and amine-containing mixtures. Recent results include glycol-aromatic hydrocarbons including multiphase, multicomponent equilibria and gas hydrate calculations in combination with the van der Waals-Platteeuw model. This article will outline some new applications...... of the model of relevance to the petroleum and chemical industries: high pressure vapor-liquid and liquid-liquid equilibrium in alcohol-containing mixtures, mixtures with gas hydrate inhibitors and mixtures with polar and hydrogen bonding chemicals including organic acids. Some comparisons with conventional...

  14. Modeling the binding affinity of structurally diverse industrial chemicals to carbon using the artificial intelligence approaches.

    Science.gov (United States)

    Gupta, Shikha; Basant, Nikita; Rai, Premanjali; Singh, Kunwar P

    2015-11-01

    Binding affinity of chemical to carbon is an important characteristic as it finds vast industrial applications. Experimental determination of the adsorption capacity of diverse chemicals onto carbon is both time and resource intensive, and development of computational approaches has widely been advocated. In this study, artificial intelligence (AI)-based ten different qualitative and quantitative structure-property relationship (QSPR) models (MLPN, RBFN, PNN/GRNN, CCN, SVM, GEP, GMDH, SDT, DTF, DTB) were established for the prediction of the adsorption capacity of structurally diverse chemicals to activated carbon following the OECD guidelines. Structural diversity of the chemicals and nonlinear dependence in the data were evaluated using the Tanimoto similarity index and Brock-Dechert-Scheinkman statistics. The generalization and prediction abilities of the constructed models were established through rigorous internal and external validation procedures performed employing a wide series of statistical checks. In complete dataset, the qualitative models rendered classification accuracies between 97.04 and 99.93%, while the quantitative models yielded correlation (R(2)) values of 0.877-0.977 between the measured and the predicted endpoint values. The quantitative prediction accuracies for the higher molecular weight (MW) compounds (class 4) were relatively better than those for the low MW compounds. Both in the qualitative and quantitative models, the Polarizability was the most influential descriptor. Structural alerts responsible for the extreme adsorption behavior of the compounds were identified. Higher number of carbon and presence of higher halogens in a molecule rendered higher binding affinity. Proposed QSPR models performed well and outperformed the previous reports. A relatively better performance of the ensemble learning models (DTF, DTB) may be attributed to the strengths of the bagging and boosting algorithms which enhance the predictive accuracies. The

  15. Research of the influence of air chemical pollutions on the health of urban population

    Energy Technology Data Exchange (ETDEWEB)

    Naumenko, T.; Smirnov, M.; Amvrosiev, P.; Kurganskaya, G.; Gritsenko, T. [The Byelorussian Sanitation and Hygiene Research Inst., Minsk (Russian Federation)

    1995-12-31

    The main problem of environmental hygiene in the Republic of Belarus is ecological situation health effects extent determination and risk assessment. The different epidemiological studies of ecological risk for public health due to atmosphere industry emissions, directed to hygiene standards correction and epidemiological and ecological situation management were conducted by the Belarussian Sanitation and Hygiene Research Institute. Atmosphere pollution of heavy industry enterprises, pharmaceutical production, the electric power stations and its impact on people morbidity in adjacent and sanitary protection areas was studied. The objective of the research is hygienic assessment and determination of public health changes, caused by atmosphere pollution, and preventive measures programs elaboration in such industrial cities as Brest, Gomel, Minsk, Grodno, Mogilev, Novopolotsk. (author)

  16. Health care policy development: a critical analysis model.

    Science.gov (United States)

    Logan, Jean E; Pauling, Carolyn D; Franzen, Debra B

    2011-01-01

    This article describes a phased approach for teaching baccalaureate nursing students critical analysis of health care policy, including refinement of existing policy or the foundation to create new policy. Central to this approach is the application of an innovative framework, the Grand View Critical Analysis Model, which was designed to provide a conceptual base for the authentic learning experience. Students come to know the interconnectedness and the importance of the model, which includes issue selection and four phases: policy focus, colleagueship analysis, evidence-based practice analysis, and policy analysis and development.

  17. Screening of 397 chemicals and development of a quantitative structure-activity relationship model for androgen receptor antagonism

    DEFF Research Database (Denmark)

    Vinggaard, Annemarie; Niemelä, Jay Russell; Wedebye, Eva Bay;

    2008-01-01

    We have screened 397 chemicals for human androgen receptor (AR) antagonism by a sensitive reporter gene assay to generate data for the development of a quantitative structure-activity relationship (QSAR) model. A total of 523 chemicals comprising data on 292 chemicals from our laboratory and data...... by the synthetic androgen R1881. The MultiCASE expert system was used to construct a QSAR model for AR antagonizing potential. A "5 Times, 2-Fold 50% Cross Validation" of the model showed a sensitivity of 64%, a specificity of 84%, and a concordance of 76%. Data for 102 chemicals were generated for an external...... validation of the model resulting in a sensitivity of 57%, a specificity of 98%, and a concordance of 92% of the model. The model was run on a set of 176103 chemicals, and 47% were within the domain of the model. Approximately 8% of chemicals was predicted active for AR antagonism. We conclude...

  18. Modeling chemical interaction profiles: I. Spectral data-activity relationship and structure-activity relationship models for inhibitors and non-inhibitors of cytochrome P450 CYP3A4 and CYP2D6 isozymes.

    Science.gov (United States)

    McPhail, Brooks; Tie, Yunfeng; Hong, Huixiao; Pearce, Bruce A; Schnackenberg, Laura K; Ge, Weigong; Valerio, Luis G; Fuscoe, James C; Tong, Weida; Buzatu, Dan A; Wilkes, Jon G; Fowler, Bruce A; Demchuk, Eugene; Beger, Richard D

    2012-03-15

    An interagency collaboration was established to model chemical interactions that may cause adverse health effects when an exposure to a mixture of chemicals occurs. Many of these chemicals--drugs, pesticides, and environmental pollutants--interact at the level of metabolic biotransformations mediated by cytochrome P450 (CYP) enzymes. In the present work, spectral data-activity relationship (SDAR) and structure-activity relationship (SAR) approaches were used to develop machine-learning classifiers of inhibitors and non-inhibitors of the CYP3A4 and CYP2D6 isozymes. The models were built upon 602 reference pharmaceutical compounds whose interactions have been deduced from clinical data, and 100 additional chemicals that were used to evaluate model performance in an external validation (EV) test. SDAR is an innovative modeling approach that relies on discriminant analysis applied to binned nuclear magnetic resonance (NMR) spectral descriptors. In the present work, both 1D ¹³C and 1D ¹⁵N-NMR spectra were used together in a novel implementation of the SDAR technique. It was found that increasing the binning size of 1D ¹³C-NMR and ¹⁵N-NMR spectra caused an increase in the tenfold cross-validation (CV) performance in terms of both the rate of correct classification and sensitivity. The results of SDAR modeling were verified using SAR. For SAR modeling, a decision forest approach involving from 6 to 17 Mold2 descriptors in a tree was used. Average rates of correct classification of SDAR and SAR models in a hundred CV tests were 60% and 61% for CYP3A4, and 62% and 70% for CYP2D6, respectively. The rates of correct classification of SDAR and SAR models in the EV test were 73% and 86% for CYP3A4, and 76% and 90% for CYP2D6, respectively. Thus, both SDAR and SAR methods demonstrated a comparable performance in modeling a large set of structurally diverse data. Based on unique NMR structural descriptors, the new SDAR modeling method complements the existing SAR

  19. Improved ADM1 model for anaerobic digestion process considering physico-chemical reactions.

    Science.gov (United States)

    Zhang, Yang; Piccard, Sarah; Zhou, Wen

    2015-11-01

    The "Anaerobic Digestion Model No. 1" (ADM1) was modified in the study by improving the bio-chemical framework and integrating a more detailed physico-chemical framework. Inorganic carbon and nitrogen balance terms were introduced to resolve the discrepancies in the original bio-chemical framework between the carbon and nitrogen contents in the degraders and substrates. More inorganic components and solids precipitation processes were included in the physico-chemical framework of ADM1. The modified ADM1 was validated with the experimental data and used to investigate the effects of calcium ions, magnesium ions, inorganic phosphorus and inorganic nitrogen on anaerobic digestion in batch reactor. It was found that the entire anaerobic digestion process might exist an optimal initial concentration of inorganic nitrogen for methane gas production in the presence of calcium ions, magnesium ions and inorganic phosphorus.

  20. Microscopic model for chemical etchability along radiation damage paths in solids

    Institute of Scientific and Technical Information of China (English)

    Mukhtar Ahmed RANA

    2008-01-01

    It would be very interesting to develop a picture about removal of atoms from the radiation damaged paths or latent nuclear tracks and undamaged bulk material in track detectors. Here, theory of chemical etching is described briefly and a new model for chemical etching along radiation damaged paths in solids is developed based on basic scientific facts and valid assumptions. Dependence of chemical etching on radiation damage intensity and etching conditions is discussed. A new parameter for etching along radiation damaged paths is introduced, which is useful for investigation of relationship between chemical etchability and radiation damage in a solid. Results and discussion presented here are also useful for further development of nuclear waste immobilization.